Kolorjet Chemicals Pvt Ltd. - Manufacturer from Malad West, Mumbai, India

Kolorjet is one of the leaders among manufacturers and suppliers of a comprehensive range of quality dyestuffs, colors and chemicals for different industrial requirements. Our range of products include dyestuff, inkjetdyes, dyes for wax printing, textile auxiliaries, synthetic food colors, natural food colors, pigments, food ingredients, dyes intermediaries, fine chemicals, specialty chemicals, enzymes, optical brighteners and soap wax dies.

An ISO 9001:2008 certified company, Kolorjet continues continues to play a leading role in the manufacturing of dyestuffs in India with the intent to further strengthen its position for its quality products. With our decades of experience and extensive industry knowledge, we have been able to face the challenges of the global market place and deliver quality products in adherence with market standards and parameters.

Whatever be your specification or quantity desired, our expertise and quality of service always remains the same. Modern production and techniques and flexible processes and procedures allow us to offer efficient service for small batch as well as large orders.

Kolorjet is a customer oriented company and work with the objective of achieving maximum customer satisfaction. The company has adopted innovative procedures and practices to meet customer expectations every time they deal with us. We always welcome any feedback or suggestions from clients in order to serve them better.

Company Factsheet

Basic Information

Nature of Business: Manufacturer

Year of Establishment: 1990

Legal Status of Firm: Private Limited Company

Statutory Profile

Tan No.: MUMG0*****

GST No.: 27AABCG2863K1ZF

CIN No.: U24110MH1995PTC086546

Quality Assurance Certificates

To ensure that each product manufactured by us meets all standard parameters and norms of international market, we provide different different quality assurance certificates. The various quality assurance certificates provided by us to our clients are:

Quality assurance certificate
Shade / strength comparison
Eco-tex check list.

ISO Certification

We are ISO Certifite

Vision

We will work together to define and understand every process performed by the organization and continuously strive to improve the quality at different stages of production and supply. Our aim is to grow by providing standard and superior chemical products and support services that are always a step ahead, eco-friendly, and loved by our customers.

We will give our customers every reason to rely on us and will achieve our vision by developing win-win partnerships with our clients and open communications with our all stake holders including associates, customers and suppliers.

Mission

Our mission is to lead the industry to the front with complete commitment and dedication on standards, quality, productivity and customer satisfaction.

Our Team

Another major asset to our sophisticated production facilities and technical expertise is our team of experienced and qualified people who are committed to achieve maximum customer satisfaction by delivering superior value products. The team works under the able guidance of our Chairman Mr. Bharat J. Mehta, under whose leadership, the company has reached so far in this business. Our senor management includes:

Mr. Bharat J. Mehta (Chairman)
Mr. Mitul Mehta (Director)
Mr. Kirit. J. Shah (Technical Director)
Mr.K.P. Johnson (Export Executive)
Mr. Jignesh Pandya (Production Manager)

Why Kolorjet?

Some of our specialties that make us a reliable business partner to work with are:

Long experience and extensive industry knowledge
State-of-the-art production facilities
Superior quality color, dyes and chemicals matching industry standards and parameters
Timely deliveries
Proven record in successful of small as well as bulk orders
Cost effectiveness
Excellent after sales service

Our Business Associates

To offer products highest quality standards, we have developed business tie-ups with some of the leading names in the field of colors and dyes. Some of our business associates are:

M/s Kolorjet Chemicals Pvt Ltd. - Reactive Dyes, Acid Dyes & Inkjet Dyes
M/s Anjana Industries - Food Colors & Natural Color
M/s Vama Colour Mfg. Co. - Pigments

Social Commitment
We, at Kolorjet, understand our responsibilities towards society and environment in which we operate. We give prime consideration to health & safety, environmental protection & accident prevention in line with any other phases of operation or administration.

We are a socially conscious company and work with the policy of providing and maintaining a safe & healthy work environment. Our operating procedures and organizational policies ensure strict adherence to practices that will safeguard the interest of all stakeholders, society and the environment.

After Sales Service:
Our after sales team include trained and friendly personnels who are always ready to assist our clients regarding their various problems and requirements. Some of the services include:

Assistance regarding product technical information, features, benefits and limitations
Guidelines about about product process and application
Economical shade matching of compatible dye stuffs in order to achieve appropriate and reproducible shades
Field Technical Services - Field technical service include Visits, technical discussion, trials, laboratory scale, pilot scale and shop floor bulk analysis
Assistance regarding the identification of new products, promotion and launching
Analysis of different products, their comparison regarding cost effectiveness, limitations and weaknesses

Industries

TextilesTo cater the needs of textile industries, we manufacture a variety of products such as dyestuffs, ultramarine blue, dyes for wax printing, inkjet dyes, textile auxiliaries, enzymes, optical brighteners, specialty chemicals, menthol crystal & peppermint, laboratory reagents etc. Produced in sync with industry standards, these high quality products are useful for cellulosic textiles industries, polyester industries, cotton industries, silk industries, wool industries, nylon industries and other various industries.

Food Processing :

We manufacture a wide collection of dyes & colors, which is extensively used in food processing industries. Made from best quality material, our range includes synthetic food colors, caramel colors, natural food colors, dyes intermediates etc. These products are used in food industries, beverage industries, dairy industries, confectionery industries, ice creams industries, soft drink industries, chocolate industries, bakery industries and many other different industries.

Leather :

We produce leather dyes in a myriad of shades, which is used for dyeing the leather in leather industries.

Paint, Ink & Plastic :

We manufacture basic dyes, solvent dyes, dyestuffs, ultramarine blue, inkjet-dyes, organic pigments, inorganic pigments and laboratory reagents to fulfill the requirements of paint, ink & plastic industries.

Pharmaceutical :

Synthetic food colors and natural food colors manufactured by us are very useful for pharmaceutical industries. These are made keeping in mind international food quality standards.

Cosmetics :

To complete the needs of cosmetics industries, we manufacture synthetic food colors, natural food colors, ultramarine pigments in various shades. These products are consumed to manufacture a lot of different cosmetics products.

Plastics :

Solvent dyes, dyestuffs, ultramarine blue, menthol crystal & peppermint are some products, which are manufactured by us keeping in mind the basic requirements of plastics industries.

Paper :

We develop basic dyes, optical brighter, ultramarine blue, menthol crystal & peppermint, laboratory reagents, Which are extensively applied in paper industries.

Colour Index

Color Index is the most authoritative way to search your exact requirement of Dyes and Pigments from the vast range of colors available today. It is basically a compendium of dyes.

The chemical names of dyes can be very confusing and complicated. As a result of this, the practice of using names that are descriptive has arisen. In the U.K. the color Index was prepared by the Society of Dyers and Colorists, while in USA it is done by American Association of Textile Chemists and Colorists. With the advent of the System of Color Indexing, many of the confusions associated with the naming and colors of Dyes and Pigments have been effectively sorted out.

Generally a dye is referred to by a simple name that is comprehended by people who is working with them. Which we can say as a common name. But the problem is that it is not uncommon for a dye to have names that are more than one. For example take basic fuchsia which was earlier known as magenta. Another example: light green, has also been popularly used to refer to dye methyl green. Some of these names are historical or there can be cases where in order to sell a single compound different manufacturers gave different names, to avoid violating copyright or trademarks of each other.

What is a Color Index

Color Index is basically a compendium of dyes, that has a huge volume of data. It was prepared in the UK by the Society of Dyers and Colorists. In the USA by the American Association of Textile Chemists and Colorists. It is available both in the book form, and on CD as well. In this reference book there is a very specific system to identify individual dyes. A five digit number is assigned to each individual chemical that is used as a dye. Consequently individual dyes get identified with reference to their CI number only. For example when specifying a dye for use in any staining method the CI number must be always provided.

The color index also has a system to assign a specific name (CI Name) for each of the dyes, to avoid any confusion regarding chemicals. The name given is totally based upon the dye's mode of behavior, base color and action. This is followed by a number. To give an example, the CI name given for chromoxane cyanine R (CI 43820) is Mordant Blue 3. Thus, the CI name therefore gives a specific way to identify a dye. Although the CI name is used less often than the CI number, the CI name is as useful in identifying a dye for a particular staining method.

The following table illustrates the use of the Color Index for yellow Organic pigment

C.I. Generic Name	C.I. Number	CAS Number	Color
P.Y.17	21105	4541-49-1	Greenish Yellow
P.Y.74	11741	6358-31-2	Bright greenish yellow
P.Y.81	21127	22094-93-5	Lemon yellow shade

Features of the Color Index

Detailed record of products that can be found in the market is put under a Color Index reference. For each product name there is a listing of the manufacturer's name, principal usages, physical form, and comments to help the customers. This format has been devised after taking into confidence the coloration industry (including prominent manufacturers, users, CPMA and ETAD)
Colorants get listed in the Color Index strictly in accordance with the system of (a) Color Index Generic Names (b) Color Index Constitution Numbers
Around 27,000 individual products are listed under a total of 13,000 Color Index Generic Names
Chemical structures that are depicted is strictly in accordance with the results obtained by modern researches on molecular conformation
Popular format has been devised with an unique 'fingerprint' concept
Part 1 of the information gets freshly confirmed with suppliers and manufacturers. Part 2 of the information is either confirmed freshly with suppliers and manufacturers or is depicted as "carried over from the previous edition

Application of Color Index

Textile manufacturers
Paint manufacturers as well as suppliers
Colorant users, suppliers and manufacturers
Manufacturers and suppliers of Plastics
Testing labs, Libraries, academic institutions
Producers of Printing ink along with suppliers

Highlights of the Color Index

The following three tables highlights major information regarding the Color Index:

Part 1

Part 1 Dye Groupings:
- Acid
- Mordant
- Disperse
- Natural Dyes and pigments
- Food
- Leather
- Direct
- Vat
- Reactive
- Ingrain Dyes
- Azoic Diazo components
- Azoic Coupling components
- Oxidation Bases
- Optical Brighteners
- Intermediate Products
- Reducing agents and Developers
Each group of Dyes is subdivided into Violet, Blue, Green, Yellow, Orange, Red, Brown and Black.

Part 2

Manufacturing methods
Structural formula (if known) of Dyes
References (literature and patents)

Part 3

Indexes
- Abbreviations of manufacturers' names
- Generic names
- Commercial names
Color Index is able to provide dye or pigment with 2 reference numbers on the criteria of
Coloristic aspects
Chemical classification:
- The first one is the area of application and technique of coloration=>the C.I. Generic name.
- The second technique is the one that is known as C.I. Constitution numbers.
There is also provision of listing all the commercial names.

What is Dye

A natural or synthetic substance used to add a color or to change the color of something. Dyes are the coloring material that color commodities of our day to day use. Dyes are applied everywhere, from Plastic toys for children to that fabrics you wear, from food to wood; hardly there is any industry where dyes are not used commercially.

A dye is a colored substance that has an affinity to the substrate to which it is being applied. It is an ionising and aromatic organic compounds. The dye is generally applied in an aqueous solution, and may require a mordant to improve the fastness of the dye on the fiber.

With the help of dyes we can easily manipulate things according to our liking. At the very basic level the use of color in identifying individual components of tissue sections can be accomplished primarily with dyes. Dyes are applied to numerous substrates for example to textiles, leather, plastic, paper, food etc. The rule that we apply to other chemicals is similarly applicable to dyes also. They also get completely or atleast partially soluble in which it is being put to. For example certain kind of dyes can be toxic, carcinogenic or mutagenic and can be hazardous to health.

Evolution of Dyes

It was in 2600 BC when earliest written records of the use of dyestuffs were found in China. The preparation and application of dyestuffs is one of the oldest forms of human activities. Evidences of which were found by Excavation at archeological sites where ancient fabrics were unearthed. There is also mention of it in the Bible and other works of classical antiquity.

The real breakthroughs in the history of dyes came in 1856 when a teenager who was experimenting at his makeshift laboratory in home made a certain discovery that acted as a sort of launching pad for the modern chemicals industry.

William Perkin an 18-year-old student was working on chemical synthesis of natural products. In a classic case of serendipity, the young William Perkin chanced upon his now famous 'Aniline Mauve' dye while he was attempting to synthesize quinine, the only cure for malaria. Perkin named his color Mauveine, after the French name of non-fast color which was made of natural dyes. So "Mauve" (a basic dye) was the first synthetic dye stuff. Mauve was a derivative of coal tar. It was the first mass-produced dye, that was commercially available and the idea was born that a color could be made in the factory. It was indeed a revolution.

What makes the Dyes colored ?

Dyes are basically ionising and aromatic compounds, they have Chromophores present in them. Their structures have Aryl rings that has delocalised electron systems. These structures are said to be responsible for the absorption of electromagnetic radiation that has varying wavelengths, based upon the energy of the electron clouds.

Chomophores make the dyes proficient in their ability to absorb radiation. Chromophores act by making energy changes in the delocalised electron cloud of the dye. This alteration invariably results in the compound absorbing radiation within the visible range of colors and not outside it. Human eyes detects this absorption, and responds to the colors.

Electrons may result in loss of color, their removal may cause the rest of the electrons to revert to the local orbits. A very good example is the Schiff's reagent. As Sulphurous acid reacts with Pararosanilin, what happens is that a Sulphonic group attaches itself to the compound's central carbon atom. This hampers the conjugated double bond system of the Quinoid ring, and causes the electrons to become localised. As a consequence the ring ceases to be a Chromophore. As a result, the dye becomes colorless.

To conclude chromophores are the atomic configurations which has delocalised electrons. Generally they are represented as carbon, nitrogen, oxygen and sulphur. They can have alternate single and double bonds.

How can the color of the Dyes be altered ?

The color of the dyes are altered by the Modifiers. The Color modifiers of methyl or ethyl groups are responsible for any alteration in the dyes; they alter the energy in the delocalised electrons. There is a progressive alteration of color by adding a particular modifier. For example: Methyl Violet Series.

The following diagram explains what happens to the color of the dyes when modifiers are added.
Step A : When no methylgroup is added the original dye Pararosanil as it is called is red in colour.

Step B : As Four Methyl groups are added the reddish purple dye Methyl Violet is obtained.
Step C : With the addition of more groups a purple blue dye Crystal Violet is obtained. It has in it six such groups.
Step D : Further addition of a seventh methyl group the dye that is obtained is called Methyl green.

What gives the Dyes Solubility and Cohesiveness ?

Auxochrome, the only substance responsible for providing solubility and cohesiveness to dyes. An auxochrome is a group of atoms attached to a chromophore which modifies the ability of that chromophore to absorb light. Examples include the hydroxyl group (-OH), the amino group (-NH2), and an aldehyde group (-CHO).

The presence of an auxochrome in the chromogen molecule is essential to make a dye. However, if an auxochrome is present in the meta position to the chromophore, it does not affect the color.

Auxochrome has the ability to intensify colors. It is a group of atoms which attaches to non-ionising compounds yet has the ability to ionise. Auxochromes are of two types, positively charged or negatively charged.

Classification of Dyes

Dyes can be classified in several ways, each class has a very unique chemistry, structure and particular way of bonding. Some dyes can react chemically with the substrates forming strong bonds in the process, and others can be held by physical forces. Some of the prominent ways of classification are given below

Natural / Synthetic
Organic / Inorganic
By area and method of application
Chemical classification - Based on the nature of their respective chromophores.
By nature of the Electronic Excitation (i.e., energy transfer colorants, absorption colorants and fluorescent colorants).
According to the dyeing methods
- Anionic (for Protein fibre)
- Direct (Cellulose)
- Disperse (Polyamide fibres)

US International Trade Commission has advocated the most popular classification of dyes. This system classifies dyes into 12 types, which are given below:

Group	Application
Direct	Cotton, cellulosic and blended fibres
Vat dyes	Cotton, cellulosic and blended fibres
Sulphur	Cotton, cellulosic fibre
Organic pigments	Cotton, cellulosic, blended fabric, paper
Reactive	Cellulosic fibre and fabric
Disperse dyes	Synthetic fibres
Acid Dyes	Wool, silk, paper, synthetic fibres, leather
Azoic	Printing Inks and Pigments
Basic	Silk, wool, cotton

Type of Dyes

The Dyes are classified based on the products to which they can be applied and the chemical nature of each dye. Dyes are complex unsaturated aromatic having characteristics like solubility, intense color, substantiveness and fastness.

A dye-formulation is supposed to have approximately 10-80% pure dyestuff. It is mostly observed that dyestuffs delivered in powder form have a higher value. While a lower value is obtained for the liquid formulations.

Dyes may be classified in several ways (e.g., according to chemical constitution, application class, end-use).

Chemical classification of the Dyes

Dyes can be divided according to the nature of their Chromophore:

	Group	Uses
Category:	Acridine dyes, derivatives of acridine >C=N-and>C=C	Textiles, leather
Category:	Anthraquinone dyes, derivatives of anthraquinone >C=O and>C=C	Textiles
Category:	Arylmethane dyes Diarylmethane dyes, based on diphenyl methane Triarylmethane dyes, based on triphenyl methane
Category:	Azo dyes, based on a -N=N- azo structure
Category:	Cyanine dyes, derivatives of phthalocyanine
Category:	Diazonium dyes, based on diazonium salts
Category:	Nitro dyes, based on the -NO2 nitro functional group
Category:	Nitroso dyes, are based on a -N=O nitroso functional
Category:	Phthalocyanine dyes, derivatives of phthalocyanine >C=N	Paper
Category:	Quinone-imine dyes, derivatives of quinone	Wool and paper
Category:	Azin dyes Eurhodin dyes Safranin dyes, derivatives of safranin -C-N=C- -C-N-C	Leather and textile
Category:	Xanthene dyes, derived from xanthene -O-C6H4-0	Cotton, Silk and Wool
Category:	Indophenol dyes, derivatives of indophenol >C=N-and>C=O	Color photography
Category:	Oxazin dyes, derivatives of oxazin -C-N=C =C-O-C=	Calico printing
Category:	Oxazone dyes, derivatives of oxazone
Category:	Thiazin dyes, derivatives of thiazin
Category:	Thiazole dyes, derivatives of thiazole >C=N-and-S-0=	Intermediate
Category:	Fluorene dyes, derivatives of fluorene
Category:	Rhodamine dyes, derivatives of rhodamine
Category:	Pyronin dyes

Dyes according to the nuclear structure

According to the Nuclear Structure, dyes are categorized into two groups

Cationic Dyes
Anionic Dyes

Industrial Classification of the Dyes

Textile Industries use dyestuff in large amount, so at this level a classification can be done according to their performances in the dyeing processes. The most consumable dye is Azo dye, around 60% of the total dyestuffs of the world are based on this dyes. Major classes of dyes in textile finishing is given here:

Acid
Azoic
Basic
Direct
Disperse
Reactive
Solvent
Sulphur
Vat
Mordant

Classification based on the source of materials

Classification of dyestuff is mainly depend upon the nature of the source from which it is made. Accordingly the classification could be:

Natural Dyes
Synthetic Dyes

Other important dyes

Based on various applications, a number of other classes of dyes have also been established, that includes the following:

Optical Brighteners - Used primarily for textile fibres and paper.
Fluorescent Dyes - A very innovative dye. Used for application in sports good etc.
Leuco Dyes - Has a wide variety of applications including electronic industries and papers.
Oxidation Dyes - Used mainly for hair.
Leather Dyes - Used for leather.
Fuel Dyes - As the name suggests it is used in fuels.
Solvent Dyes - For application in wood staining and production of colored lacquers, solvent inks, waxes and coloring oils etc.
Inkjet Dyes - Writing industry including the inkjet printers.
Smoke Dyes - Used in military activities.
Sublimation Dyes - For application in textile printing.

Dye House

Dye House is a building in which dyeing is carried on.
For improving quality and fast turn around, there is a need of fully integrated dye house network that comprises of a vast range of automated system components properly synchronized to each other. With the proper integration of dyeing equipment into a sound organized network, it is quite obvious that the dyehouses can give away its valuable resources very cheaply.

A typical Dye house network should be equipped with the machines that are capable of performing a number of operations like dyeing, heat setting, compacting, stentering, hydro-extraction, brushing and washing etc. Another vital task is the control of the system. Although every single device from the color kitchen to dyeing machines these days are PC-controlled, however modern dye houses prefer to employ a Dye house automation system.
Dye house automation system ensures that the machines are able to synchronize with each other and can optimise their capacities. Apart from this the automation system facilitates linking of the order management with the necessary machine control units. This helps to complete a fully integrated dye house network. The diagram that follows next gives a perfect example of Dye house that is complete in every respect. Most modern dye houses are today following the concept of totally networked Dye House.

Benchmarks of a Dye House

A perfect dye house should meet the following criteria, that are given below:
A perfect dye house should meet the following criteria, that are given below: Computer aided Dyeing system- By implementing a Computer aided Dyeing system it has been possible to cut down on both costs and time. For example it has been found that by using the system there has been reduction in the acrylic dyeing batch time by at least 30 percent.

Modern laboratories- New formulas are first tried in the lab before implementing in production. If there is closer liquor ratio agreement between the production and laboratory, better would be the final result.

Package preparation- Latest stainless steel spacer should be used for holding the shape of package ends. This allows for smooth unwinding. Though backwinding to paper cones along with intermediate lubrication is more in vogue, but that costs money and time. Dyers must master new ways to bypass the idea of backwinding.

Package handling- Increasingly the dye houses are insisting on the technology of robotic package handling. Use of Robotics demands uniformity. Robots need the packages to be placed in a specific location.

Quality- In today's fiercely competitive market, if a manufacturer doesn't have a consistent quality, probably they just can't stay put in business. Therefore a manufacturer must insist on receiving only quality and genuine products from suppliers. In fact adhering to different International quality standards that has written down procedures and manuals is now more than just a norm. There are now various information technology companies that are into the field of operations management. If they are called for and allowed to work on a program at a dye house and follows up it through the completion, then a dye house will be equipped with a totally integrated data base system. This will offer solutions in every sphere of operations like manufacturing, production, financial, forecasting, planning, scheduling and delivery.

Challenges of globalisation- Over the years the supply of material has changed. Today suppliers are challenged from across globe with products of superior quality, and low cost. For example yarn suppliers continues to search for non-branded suppliers of polyester and acrylic for replacing more costlier brand names. Today's mantra is innovate or perish.

Savings in energy- Saving in energy, chemicals and water is now vital for survival of any dye house. Machine vendors are now constantly redesigning dye machines that has the lowest liquid to goods ratio. For example a high pressure dyeing machine consumes much less water for processing. The liquid to goods ratio being 1:5 (i.e. to process 1 kilogram of fabric, five litres of water are used) now compare this to traditional units that are fitted with conventional winches whose water to liquid ratio is in the range of 1:15 or even sometimes 1:20. Survival for such dye houses is impossible.

Maintenance- It is a general tendency to view maintenance time as an opportunity lost to manufacture dyed sales yarn. Preventive maintenance is clearly less expensive than unscheduled halt and a spoiled dyeing.

Dyeing Process

Dyeing is the process of adding color to textile products like fibers, yarns, and fabrics. Dyeing is normally done in a special solution containing dyes and particular chemical material..

The most widely publicised dyeing process is in the context of textile dyeing, but now the dyeing process is used in a variety of industries like: leather, plastics, paint, printing and many others.

Dyeing Process of Leather

The process of tanning and dying leather is ancient. Primitive man was a society of hunters and gatherers who used everything they caught, which meant that after an animal was eaten, its carcass, hair, skin and organs needed to be used. Animal skins quickly putrefy, so these people had to quickly discover a way to preserve them.

Adding color to cured animal skins - or simply put, dying leather - is a part of the tanning process. The dying process is usually done in the third and final stage of a tanning process, but is sometimes done in the second stage, at the same time as the actual tanning. Tanning leather is necessary to preserve an animal skin for use in making products like purses, jackets, luggage and shoes. In ancient times, leather was used on everything from battle armor to chariot wheels.

There is a lot of scope of experimenting with the dyes on the leather. You can add designs, pictures or monograms on the leather, to make it look more attractive. However, to achieve such results you need a lot of practice.

There are mainly two different types of leather, used for making leather items. One is the aniline leather that shows the natural characteristics of the hide. The other one is the nubuck leather, which is aniline leather that has been brushed and polished to obtain the texture of a velvet. The steps to dye leather have been given below:

Selecting the Right Dye- Choose the dye on the basis of the dyed leather samples that are provided by the shop owners at the time of purchase. This is because, most of the dyes, when applied on the leather, give an altogether different color than what they seem when kept in a bottle.

Preparing the Leather before Dyeing- In order to maintain its natural color, leather surfaces are often coated with a protective covering. If this coating is not removed from the leather, then you may find the leather in a dull and mutilated condition after dyeing. Clean off coatings or any other dirt present on the leather with the help of a leather deglazer.

Application of Leather Dye- Spray water on the leather or apply it with the help of a moistened sponge. Start applying the dye, when the leather is evenly wet. While dyeing, try to keep your strokes long and to ensure an even distribution of the color all over the surface of the leather. It may happen that one coat of the dye may not give you the desired shade. In that case, you have to apply more number of coats.

Drying Process- When the surface of the leather does not have a wet look that means that the dye on the leather has dried up. On an average, it takes almost one to two hours for the dyed leather to dry. To a great extent, the drying time depends on the type of the leather to be dyed. During this time, you need to flex the leather a number of times, in order to loosen up its fibers. In this way, you can prevent the leather from stiffening up.

Final Touch- Giving final touch to leather is most important. The next step that follows drying, is buffing up the leather with the help of a soft, clean cloth for removing the extra dye present on the leather. It also helps the leather to get a polished look. Finally, you have to coat the dyed leather with leather finish. Leather finishes are available in spray cans. You can directly spray it on the leather surface or apply it with the help of a wool dauber. The finish should spread on the surface evenly.

Textile Dyeing Process

Dyeing is a method which imparts beauty to the textile by applying various colors and their shades on to a fabric. Dyeing can be done at any stage of the manufacturing of textile- fiber, yarn, fabric or a finished textile product including garments and apparels. The property of color fastness depends upon two factors- selection of proper dye according to the textile material to be dyed and selection of the method for dyeing the fiber, yarn or fabric.

The following figures illustrate with process flow diagrams the whole operation of finishing processes and how the dyeing process is a part and parcel of the process of textile making.

Materials used in the Textile Dyeing Process

Materials that are used in textile dyeing process include water, fibre, yarn or cloth. Further, these include a host of process chemicals like:

Acids, e.g. acetic, formic.
Alkalis- NaOH, potassium hydroxide, sodium carbonate.
Bleaches- Hydrogen peroxide, sodium hypo chlorite, sodium chlorite etc.
Dyes, for example direct, disperse, pigment, vat.
Salts, e.g. NaCl.
Size, e.g. PVA, starch.
Stabilisers from sodium silicate, sodium nitrate also organic stabilisers.
Surfactants
Auxiliary finishes, like fire retardant, softener

Methods of Textile Dyeing

Color is applied to fabric by different methods of dyeing for different types of fiber and at different stages of the textile production process. These methods include: Direct dyeing, Stock dyeing, Top dyeing, Yarn dyeing, Piece dyeing, Solution pigmenting or dope dyeing, Garment dyeing etc.

Textile materials are generally dyed using two processes. They are the following:

Batch Dyeing Process
Continuous or Semi- Continuous Process

The following chart gives a comparison between batch dyeing and continuous dyeing

What is Pigment

Pigments are used for coloring paint, ink, plastic, fabric, cosmetics, food and other materials. Most pigments used in manufacturing and the visual arts are dry colorants, usually ground into a fine powder. This powder is added to a vehicle (or binder), a relatively neutral or colorless material that suspends the pigment and gives the paint its adhesion.

A pigment changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.

Features of the Pigments

The pigments are versatile coloring agents that comes with all round features to give credence to its suitability in a variety of mediums. Some of the striking features are given here:

Excellent solvent resistance properties
Excellent light and weather fastness
High tinting strength
Good over spray fastness when applied in paints
Gives heat stability of around 300° C in the case of Polyolefins Plastics
Easily dispersible
Consistency and uniqueness of shades
A good baking stability that makes them suitable for automotive and other industrial paints

Factors That Go In Selecting The Right Pigment

Factors in choosing right pigments are as follows:

Color
pH value
Hiding efficiency
Bulking value
Density
Hardness
Oil absorption
Refractive index

The Following Table Gives A Good Comparison Among Various Classes Of Pigments

Comparison of Pigment Families

Property Behavior	InorganicPigments	ClassicalOrganic Pigments	SpecialtyOrganic Pigments	OrganicDyestuffs
Opacity	Usually high	Translucent to Transport	Translucent to Transport	Very Transparent
Color Strength	Low to moderate	Considerably stronger than Inorganic Pigments	Considerably stronger than Inorganic Pigments	Strongest
Dispersability	Usually Good: Often Abrasive	Adequate	Poor to Good	Not required; Soluble
Heat Resistant	Usually 500⁰ F; Some 200⁰ C	150⁰ C-300⁰ C	200⁰ C- 300⁰ C	250⁰ C- 350⁰ C
Migration resistance	Excellent	Moderate -Good	Good - Outstanding	Very Poor - Good
Light Fastness (on a Blue scale)	6 to 8	2 to 6	6 to 8	2 to 7
Weather resistance	Outstanding for selection	Insufficient	Excellent for Selection	Good for Selection

Application of Dyes and Pigments

Dyes
Dyes gives jazzy colors to the t-shirt you wear or the shinning black to the leather shoes. They give colored print out from your printer. Perhaps there would be a very few applications, where there would be no use of the dyes. Constant researches done over the 20th century and there after has resulted into every imaginable form of color of dye. Modern dyes serves more than just being pretty. They have become indispensable tools for a variety of industries.

From acting as colorants for plastics, Textile dyeing industries and the highly sophisticated biotechnology industry dyes are touching our life everywhere. Dyes are also used by industries for inks and tinting. Today, a wide variety of dyes are manufactured to meet the requirements of each type of industries. Dyes are available in various forms. Example: dry powders, granules, pastes, liquids, pellets, and chips.

Other industries where dyes are used in a variety of products include paper and pulp, adhesives, art supplies, beverages, ceramics, construction, cosmetics, food, glass, paints, polymers, soap, wax biomedicine etc.

Dyes that cater to specialty industries often come with specialized properties that include:

Resistance to weather conditions
Resistance to ultraviolet light (UV)
Resistance to heat
Conducts electricity
Contain reinforcing fibers
Free from heavy metals
Some products are water soluble

Pigments

These days, the role and application of pigments have increased manifolds. There would hardly be any industries left where Pigments do not play any substantial role. The challenge is now to discover pigments that are capable of not only long-lasting applications but also are environmentally safe. A few of the important applications of Pigments is given below:

Printing inks- Pigments are used in all kinds of printing inks, that includes inks for printing metal foils, lacquers etc.

Paints- A diversified application in the whole gamut of paints that include decorative and protective coatings, in paints that are oil and resin based, automotive finishes, emulsion paints, distempers, aqueous based paints like lime etc.

Pigment finishes for leather and textiles- Coloration application for popular textiles such as polyesters, nylon etc.

Coloration of Plastics- Pigments are used in host of plastic applications that includes poly vinyl chloride(PVC), rubber and synthetic polymers, urea-formaldehyde(U-F) and melamine-formaldehyde moulding powders polystyrene, nylons, polyfins, phenol-formaldehyde(P-F), acrylonitrile-butadiene-styrene resins (ABS).
Coloration of cement glass paints
Coloration for papers
Colors for cosmetics

Cement Industry

Concrete is derived from cement. For about last one century, pigments have been using with concrete to give them different colors. When pigments are mixed with concrete, then actually, these pigments tint the color of the paste portion of the concrete.
Color Pigments used in the Cement Industry Color Pigments are used in the cement to ensure a long lasting cement color shade. But for this, the pigment must have a good quality. These pigments (color) are made from both natural and synthetic iron oxide, cobalt, titanium dioxide and chromium oxide. From iron oxide pigments, red, black and yellow color can be obtained. From cobalt pigments, blue color can be obtained. White color and green color can be obtained from titanium dioxide and chromium oxide respectively. Other colors like buffs, brown, tans, coppers, oranges, chocolates and many other colors can be obtained from the blends of the red, black and yellow colored iron oxide pigments. These colored pigments are: water- wetable, lightfast, alkali resistant and will not negatively effect the firmness and strength of the cement. But, one thing should we remember about the concentration of these pigments in the cement. This concentration should be within the range of 10% of the weight of the cementitious ingredients.
Iron Oxide Pigments Iron Oxide Pigments is one of the most commonly used pigments with concrete. These pigments are combined with concrete to protect the concrete from fading or to prevent the leaching out of concrete. The primary colors of Iron Oxide Pigments are available in red, yellow and black. With the red colored Iron Oxide pigments, shades of blue or orange can be found. To create multitude of colors, these pigments having of different colors are combined together according to a certain ratio. Still today, the use of Iron Oxide pigments is maximum. The few reasons of this popularity of this pigments in the cement industry are:

Inexpensive
Non-toxic nature
Don't fade easily

But, gradually, the use of iron oxide pigments in cement industry has been replaced by other synthetic pigments

Cobalt
Cobalt generates the blue effect in the cement. But, it is expensive one. So, it is used in some special cases.

Titanium Dioxide
Titanium dioxide produces the white color effect in the cement and other related materials.
Chromium Oxide
It generates the green effect in the cement. But, it is expensive one. So, it is used in some special cases.
Process of combination of cement & pigments Generally, the pigments don't react with cement, because pigments are inert in nature. So, pigments are not be counted as cementitious material contents. But, whenever pigments are mixed with cement then, these pigments form color of cement grains. This is possible, because pigments bond with the cement via the hydration process.

The different forms of pigments applied in cement industries The different forms of pigments are: Powdered form, Granular form and Liquid form. Pigments work well in all three different forms, but, these require different handling process and composition should be different. The most oldest form of pigments is the powder form.

Applications of Pigments in the Cement Industry

Colored Block
Block Paving
Concrete Walling
Patterned Concrete
Concrete Products

Colorants for Agriculture Industry

There are three main types of agricultural industries that uses the dye:

Crop protection industry
Fertilizer industry
Seed dressing industry

The purpose of the dye used here is for coloring of agricultural chemicals or in the identification process of agricultural chemicals. The basic selection criteria depends upon the following:-

Dye color
Color strength of the particular dye
Color stability
Compatibility of the dye with the particular agent

Fertilizer IndustryIndia has got a good rank in the fertilizer production over the world.
Fertilizers are often added with coloring to differentiate between qualities and to avoid any type of errors in application. Fertilizers are also colored for purely marketing purposes. Usually water based pigment is often used in the diluted form and is sprayed onto the fertilizer or sometimes incorporated into a melt.

Seed Dressing IndustryThe main objective of coloring the seed dressings is used for marking and for warning reference. To avoid any sort of confusion and making sure that it does not end up being used as fodder. The most important colorant used here is red with typical concentrations of 600 ppm.

Crop Protection Industry Use of colorants in crop protection agents of the type insecticide and fungicides helps to clearly demarcate treated areas from the untreated ones. In addition, the dye stuffs also help in promoting safety in the handling operations.

Coloring of pesticides or herbicides is generally done by mixing chromatic pigments with dry powder formulations of the agents. Milori blue is a very popular pigment, that goes well with viticultural fungicides, other categories of pigments include lithol rubine, heliogen blue etc. Dyes used in the crop protection industry are Solvent dyes, Acid dyes or Basic dyes.

Colorants for Security Printing

Fluorescent Dyes and Luminescent Pigments are widely used in Security Applications

Considerable research over the last decade or more on the study of fluorescence has bore fruits in the form of development of new fluorescent dyes. These security dyes are now applied increasingly in the very sensitive area of security printing. The fluorescent dyes are providing ways to create and apply effectively controlled "signatures". The USP of these dyes are that they are customized and are printed as patches on different kinds of surfaces. Each of them has a signature element that is able to identify the patch as authentic. As the different dye formulas are able to vary their fluorescence characteristics in various repeatable ways, as a result unique signatures can be achieved. A very popular Example of a dye that is used in security printing is that of Coumarin 1.

These days a new range of luminescent has been developed that are either excited by UV or IR and applied in security printing applications. Here a few specific uses of the luminescent pigments in the security printing is discussed:

Brand Protection and Security of Products- In applications that involves product security, Luminescent pigments are used in making tamper evident seals for pharmaceuticals and other products. When it comes to brand protection, luminescent pigments and fluorescent dyes are used for proprietary invisible security marks and features which gets printed on products, packaging and labels.

Security Printing and prevention of counterfeiting- Security marks and features that are not visible under normal light are made with Luminescent pigments. They cannot be duplicated even by the ultra sophisticated photocopiers. While they can be easily verified using a very simple Ultra violet light or a luminescence sensor. That is the reason for security printing of stamps, checks, credit cards, licenses etc. are done with Luminescent pigments.

Property Identification and Prevention of loss- As the invisible security marks created by luminescent dyes are not visible under normal, do not deface the property and cannot be removed they are an ideal forensic tool.
Key Features of Fluorescent Dyes

Minute changes made in the dye formula has the capacity to change the fluorescence characteristics that can noticeable, and measurable as well.
The Fluorescent Dyes are produced and subsequently modified during manufacture in an unique manner so that only one single particular image will produce the anticipated signature characteristics. Thus making duplicacy very difficult.
The Fluorescent Dyes have been developed to make them compatible with conventional inkjet printers. This capability has resulted in digital encoding of uniquely identifiable overt or covert marks. It is changed periodically thus making counterfeiting a very short term value or virtually a futile effort.

Dyes in Medicine

Dyes are an important ingredient in many of the medical tests. Many of the tests that are carried out on patients use the dye to get accurate results. One such example is that of Fluorescein angiography.

Fluorescein angiography derives its name from fluorescein, the dye that is used is very successfully for carrying out the tests. Angiogram is a very valuable test that gives information about the circulatory system.
The work process of Fluorescein angiography test: First a special dye, called fluorescein is injected into a vein in the arm. Within seconds, the dye reaches the blood vessels inside the eye. A camera with special filters that will highlight the dye is used for photographing the fluorescein as it keeps on circulating through the blood vessels in the back of the eye. The dye has the ability to detect abnormalities like circulation problems, swelling, leaking or abnormal blood vessels, which it will show in the photographs. The doctor then decides on the diagnosis, and possible treatment options.

Rubber Industry

For bringing different properties like durability, resistance against heat and light reinforcement capacity etc., in the rubber products, different types of pigments are applied. Some of the pigments that are applied/used in the rubber industry are:

Organic Pigment Powders
Used to develop other specific properties in the rubber made products.

Titanium Dioxide
Titanium Dioxide are used during the application process of rubber because these pigments have some good qualities. These good qualities are: high refractive index, consistency in the size of the particles, dispersibility, and high ultra violet ray resistance.

Carbon Black
Carbon Black is a type of pigment which is derived from the refinery process of petroleum. In tyre manufacturing process, it is used for producing high resistance, abrasion and longevity and grip.
Carbon black has wide variety of applications in different kind of rubber products. This range of rubber products starts from aerospace to ordinary household products.

Florescent Pigments
Florescent is a kind of bright pigment and its powder form i.e. called as Powder Color is used in the rubber industry. This kind of pigments may be both organic and inorganic nature. The proper color selection depends primarily upon some requirements of the manufacturers such as: light stability, heat stability, resistance to bleed, resistance to migration and required shade.

Molybdenum Pigment
Molybdenum Pigment is used in the Rubber Industry. These pigments are light, heat stable and having bright color range from bright red-orange to red-yellow. Apart of rubber products, these pigments are also used in ceramics, plastic, paints and inks. The other kind of pigments that is known as Ultramarine pigments, are also used for rubber products. These pigments have high heat resistance, light and weather resistance.

Bifunctional Organic Silicon Compounds
The pigments which are used in the rubber industry, are generally bifunctional organic silicon compounds. These compounds have two reactive groups. For high quality rubber compounds, these pigments are used. When this kind of pigments are used in the rubber industry combined with sinaloan group-carrying pigments, then the effectiveness will become more effective.

Cadmium Pigments
Cadmium pigments have no major application in rubber industry, but, for many minor purposes, these pigments are used in the rubber industry.

Zinc Oxide (Zinc White) as a Pigment Zinc Oxide is used in rubber industry since its inception.Some special properties of Zinc Oxide that make it popular for the rubber industry are:

Rubber - Metal Bonding
Zinc oxide reacts with copper oxide for the bonding of rubber to brass.

Hear Stabilization
Zinc oxide has a very high stability (resistance) of heat. So, when it is used for tyre manufacturing, then tyres become more stable and durable even at the high temperature.

Latex Gelation
It gives enough stability in the gelation of foam, when latex foam rubber product is manufactured.

Pigmentation
As zinc oxide has high brightness, high refractive index and proper particle size, so, when this pigment is mixed with rubber products, then the products will become more whitish.

Light Stabilization
Out of all other white pigments, Zinc oxide has the maximum capability to absorb the Ultra Violet rays. So, when it is used with the rubber tyres, then the rubber tyres get extra stability to the destructive sunlight.

Ceramics Industry

The applications of different pigments on ceramics are as follows:

In developing Ceramic Pigments- These special kind of ceramic pigments can be developed with the help of other pigments and ceramic powder. How much of which pigment will have to use depends upon the desire color intensity. But, the quantity of pigments that is used for these applications can vary from 1% to 10%, this variation does not make any noticeable impacts on the substances. Enamel (colorful) can be produced by coloring the melt during manufacturing. Enamel can be also generated by mixing coloring stains during the milling process.

In Coating Ceramic Materials; Ceramic Glaze; Frits- The attractive looking products with more durability and utility are obtained by formulating these coating applications of pigments on ceramics.

In Glaze development- One of the application of pigments on ceramics is to develop leading glazes for various whiteware ceramics. These include sanitary ware, tile, dinnerware etc.

In preventing Ceramics Corrosion and color fading- In this process, by applying pigment coating and protective layer with other kind of chemicals, the corrosion of the metals can be prevented. The lasting effect of colors also increase.

Coloring process of Ceramic products To color ceramic products and glass products, heavy metal oxides are either dissolved in the ionic coloration (melts) or can be incorporated into the melt like pigments or pigmentation process can be adopted.

There are several factors on which the coloring effects of the pigments and stains depend, and these are:

Nature of the raw materials
Firing temperature
Dwell time and kiln atmosphere.

For coloring the sanitary ceramics, a number of inorganic pigments are required.

Some important pigments for ceramics Cadmium, Tin-Oxide, Nickel-hydroxycarbonate, Ceramic Glaze Pigments etc., are the some other important pigments that are used for ceramics.

Tin oxide pigments are versatile materials for ceramics. The thermal stability and chemically inert nature of tin oxide enable it to generate a board palette of durable ceramic color.

Cadmium pigments provide a wide range of rich color to the ceramics, like red, orange and yellow. Cadmium pigments are highly resistance to heat and pressure and very less soluble. So, these pigments are exposed to high temperature or pressure during the application process to ceramics.

Cobalt as a pigment for ceramics As a pigment, cobalt is more famous for ceramics. The color imparting capacity of cobalt containing minerals is very old. It has been utilizing as a pigment from the ancient period. This property of cobalt has been used in glass, ceramics, paints, inks, porcelain etc. Some unique properties, that make it the most widely applicable pigment for ceramics are: solubility, stability, coloring effects etc.

Colorants for Cosmetics Industry

Dyes have found a wide variety of uses in the cosmetics industry. Be it the hair dyes or lipsticks or nail polish shampoo everywhere there is wide use of dyes. Let us look at hair dyes. Most of the commercial hair dye formulas available now are complex, that uses bunchful of ingredients, and the formulas also differ considerably with manufacturers. Since we are interested in the dye part let's see what kind of dyes are used in making of hair dye. The dye chemicals that are used usually consists of amino compounds, like 4-amino-2-hydroxytoluene and m-Aminophenol. Pigments of Metal oxides, like titanium dioxide and iron oxide, are also used. The process of manufacturing hair dye is illustrated in this diagram.
Types of ingredients used in the cosmetics The majority of colors used in cosmetics are pigments. It is the inorganic pigments that are popular with cosmetics but are subject to purity levels of heavy metals. The range of inorganic pigments used in cosmetics is generally made up of various chemical types. A few of the popular ones is provided in the table:

Pigments	Features and Applications
Chromium Dioxides	Shades range from dull olive green, to a blue green, or bright green, finds use in most categories of cosmetic preparations but prohibited for use in lip products in the USA.
Ultramarines	Shade range from bright blue to violet, pink and green also, not allowed for lip products in the USA.
Iron Oxides	Three basic shades: black, yellow and red, finds use in liquid foundations, face powders, and blushers.
Mica	Mica gives a natural translucence when used as face powders and powder blushers.
Manganese Violet	Shade is purple.
Iron Blue	Color is dark blue, used in a wide range of applications.
White Pigments Titanium Dioxide Zinc Oxide	White pigments have a wide use in all cosmetics, they show extremely good covering powder, are almost totally inert also extremely stable to heat and light.

In addition to this some types of organic pigments are also used along with water soluble and oil soluble dyes in the cosmetics application. Some examples of water soluble dyes are given here:

Dye	C.I. Number	Colours
Carotene PS 300	75130
Annato Hydrosouble	75120
Carmin of Cochineal	75470

Glass Industry

Now a days, the world market is flourishing with several new types of pigments that are used for coloring the glass equipments. In past, the various kind of impurities were responsible for producing colors in the glass equipments. For example, in the 17th century, in the 'black bottle glasses', the color dark brown or green was found due to the present of iron impurities. These impurities came in these glasses from two sources. One, and was used to make these glasses and second, sulphur from the smoke of the burning coal was used for melting these glasses.

But, today, the glass is colored by using various kinds of pigments (Purified metal salts). Some ancient examples of colored glass are: ruby glass (gold chloride is used as a pigment, invented in 1679), uranium glass (uranium oxide is oxide as a pigment, invented in the year 1830). It doesn't mean that, for every time, the colored glasses are useful. Sometimes, we need such glass, which is free from any color. At that time, we have to removed the unwanted color from the glass. The process of removing the color is called as Decolorizing process. Some commonly used decolorizing agents are: Manganese dioxide and Cerium Oxide.

Special Effects in Glasses By Using Pigments Special color effect can be generated in the glasses by using some pigments either individually or in the combined form with other types of pigments. For example, Iridescent glass (Iris glass) has a special coloring effect. This coloring effect in the iris glass can be generated by adding some metallic compounds (pigments). Sometimes, the coloring effect, in the iris glass can be generated by spraying its surface with lead chloride and then heating it in the present of reducing agent. Another colored glass is Dichroic glass. From different angles, the color in the glass seems to be changed. This is happened because, a very thin layer of colloidal metals (gold or silver) is applied on the surface of the glass.
Some pigments and their coloring effects in glass

Name of Pigment Compounds	Coloring Effects
Iron Oxide	Green, Brown
Manganese Oxides	Deep Amber, Amethyst, Decolorizer
Cobalt Oxide	Deep Blue
Gold Chloride	Ruby Red
Selenium Compounds	Reds
Carbon Oxides	Amber/Brown
Mix of Manganese, Cobalt, Iron Black, Antimony Oxide	White
Uranium Oxides	Glowing Yellow-Green
Sulphur Compounds	Amber/Brown
Copper Compounds	Light Blue, Red
Tin compounds	White
Lead with Antimony	Yellow

Some Usable Pigments in Glass Industry

Sodium Antimonate
Sodium Pigments are also used as a decolorizing agents in the glass industry. These pigments are used as a refining agents.

Nickel Inorganics Pigments
Nickel Inorganic Pigments are used to add colors, enhance the strength in the end glass products, and some other features in the glass products.

Cobalt Inorganics Pigments
Cobalt inorganic pigments are used in various applications. These applications vary from adding colors, increasing strength to produce finished glass products.

Antimony Trioxide (Sb₂O₃)
These pigments are also known as White Pigments. These pigments are used in the glass industry as decolorizing agents. To remove the unwanted colors from the glasses, these pigments can be used. There purification capacity is very high and free from all types of impurities.

Wire and Cable Industry

The Wire and cable industry use various types of pigments to color polyolefins. Mainly they are employed for Wire Identification Methods. As in cables, it can be seen the coloring done on the outer layer is governed by a different set of requirements as from the inner layers. Pigments that are used in the wire and cable industries can be of two types inorganic and organic. Newer alternatives that are coming in to the market are known as the "mixed-phase metal oxide" pigments. Examples: yellow nickel Titanates and blue and green cobalt Aluminates. A relatively new entrant is the brilliant yellow bismuth vanadate.
Organic pigments are also used but not as popular because they are more difficult to disperse than inorganic ones leading to possible loss in mechanical strength.

Some common examples are given in this table:

Pigment	Color	Application
Titanium dioxide	White	Used in Variety of resins
Zinc sulphide	White	Wide use
Iron oxides	Red, yellow, brown, and black	Wide use
Lead chromates and lead chromate molybdates	Colors can include bright yellow and orange	Good use
Cadmium	Comes in reds, yellows, oranges and maroons	Excellent for engineering resins
Chromium oxides	Green	Shows good heat and light fastness, variety of uses
Ultramarines	Comes in blue, pink and violet shades	Works in a wide gamut of resins

Factors in Selection of Pigments

There are various factors that govern the choice of colorants when it comes to the Wire and Cable industries:

Humidity
Thermal cycling
Sunlight
Air pollution
Light stability
Resistance to fading
Exposure (Outdoor & Indoor)

Wire Identification Methods
In modern Wire and cable industry, there is a constant need for effective wire identification.
Inkjet Marking- Inkjet technology has vastly improved over the years. With features of less maintenance and faster start-ups, Inkjet marking systems are now more reliable and user friendly. For the wire and cable industry, a dye or pigmented ink, with an Methyl Ethyl Ketone base is applied.
Hot Stamp Marking- Hot stamp marking is still among the most inexpensive techniques for wire identification and is perhaps with exception of laser the only viable option for marking of the Teflon insulated wire. Four important factors here are correct air pressure, dwell time, wheel temperature, and lastly foil. Use of pigments come in the foil part. The foil comprises of a backing and pigment. The pigment gets transferred to wire insulation through the heat emanating from the character wheels. It is vital to note here that certain types of pigments can stick to only particular substrates and would need different temperatures to transfer them.

Colorants for Plastic Industry

Color is an integral part of the plastic material and it should not be considered as an after thought. The whole system of coloring has to be deal with using what is called a total systems approach. No doubt the color enhances the functionality, but it has also the potential to degrade certain material properties like impact strength, if not applied properly.

The colorants that are used in the Plastic Industries can be both the dyes and pigments. Both dyes and pigments exhibit color through the process of visible light absorption and scattering. Typically color formulations generally have four colorants. Black and white are used basically to control the value and Chroma, while two colored pigments or dyes are applied to establish the Hue.

Dyes that are used in the plastics industry must be very strong, show good heat stability and be transparent. Typically the dyes are used to tint or shade a resin. In the plastics industry dyes are limited in use, as such they can be used for only a selected number of resins. Pigments used in this industry can be organic or inorganic. While pigments offer more choices to the manufacturers due to its opacifying ability, broader chroma range, and better heat stability for most of the resins. Pigments are generally dispersed within a resin matrix, while dyes solubilize in the resin. Titanium Dioxide is a pigment that has a wide use in Plastics industry. It is used to make the plastics more whiter, brighter and durable.

Dyes or Pigments? A base polymer dictates the choice of the colorant selected. Pigments are typically used in polyolefins as most of dyes show a tendency to migrate in polyolefins. While Dyes are often successfully used with polycarbonate, polystyrene, acrylic, and other types polymers because of their color strength and transparency. The final word is whatever be the colorant selected it must show compatibility with the base resin. This is in order to prevent a color shift occurring over time.

Have a look at the properties of few of the colorants that constitutes both dyes and pigments:

Type of Effect	Pearlescent	Metallic	Fluorescent	Phosphorescent	Thermochromic	Photochromic
Cost	Low	Low	Low-High	Medium	High	High
Polymer compatibility	All	All	Dyes: PMMS, PET, ABS, Pigments:PE, PP	PMMS, PE, PS	All	All
Durability	Excellent	Excellent	Fair	Good	Fair	Fair

Factors in selection of right colorant

End-use application requirements
Weather fastness
Colorant loading
Dispersion method
Resin type
Dimensional stability
Processing Temperature
Heat stability: A careful choice of inorganic and organic pigments from the view point of temperature is vital for maximizing color and performance
Gloss
Type of polymer(s) being used
How is the polymer(s) being processed
What kinds of functional additives are required like plasticizers, stabilizers, flame retardants, slip agents, etc.
The exact application (whether general purpose, food contact item, toy, package subject to CONEG regulation etc.)

Colorants for Printing Inks

We all use inkjet inks in our printers of various hues and application. The most vital part of the inkjet printer is the ink that we use in the cartridge. In fact the determinants of the quality of printing are the type, quality, and the quantity of ink in the cartridge. Inkjet inks are classified into the following four types of categories:

Water based
Oil-based
Solvent-based
Curing
Hybrid ink

Buying Tips
Obey the rules- First and foremost is to obey the printer manufacturer's advices.
Watch out for compatibility- The association of ink and paper is a complex one and difficult to optimize. It has been often seen that bargain-priced inks or papers leads to results that is not upto the mark.
Working ink-paper pairs- Normally the following combination has been seen to work better:

Dye/ colorant + coated paper
Pigment + nanoporous paper

Smart Choice between pigments and dyes- Remember the choice you make is some sort of a delicate balance between quality of the color and the factor of longevity. Dyes are the way to go if your criteria is good life and and color.
See the color gamut comparison charts in proper perspective- Do not hesitate to ask for direct comparison prints on exactly the type of media that you would be using.
Water based inkjet inks
Water based inkjet inks are very common inks that are used for printing. They are generally used for application in paper. Basically, the water or aqueous ink formulations comprises mainly of a carrier fluid that is able to keep the liquid in a liquid state thus acting as a sort of carrier for the fluid. They do not contain any volatile organic compounds in them and has a very low level of toxicity.
Water-based inkjet inks as a product can be broadly classified into two general categories:

Dyes for Water Based Inkjet Inks
Pigments for Water Based Inkjet Inks

The diagram given below illustrates both the type:-
This diagram makes clear that dyes get fully dissolved in the carrier fluid whereas pigments are fine powders of solid colorants and get dispersed in the color fluid.
To understand the role of dyes and pigments in Water based inkjet inks, first there is a need to look at the basic ingredients of a water based inkjet inks.

Ink component	Use	wt-%
Colorant	It gives the ink it's basic function - absorbing of light of the specific wave length band	2-8
Carrier fluid	Suspends or helps in dissolving the colorant	35-80
Surfactant	Helps to promote wetting by lowering the surface tension	0.1-2.0
Humectant	Helps in inhibiting evaporation(mixes with the carrier fluid)	10-30
Penetrant	Helps to penetrate ink in the paper surface	1-5
Dye solubilizer	Helps to promote dye solubility in the carrier fluid	2-5
Anticockle additive	Checks interaction with paper fibres that can very well lead to paper cockle	20-50

Pigment or Dye: The Great DebateThere has been a great debate regarding which medium is better whether dyes or pigments. Though there is no conclusive evidence regarding the superiority, but both Dyes and Pigment-based inks have their plus and minuses. While water based inkjet inks using dyes has been a traditionally favoured process. But with changing times pigment based inks are getting increasingly accepted as a choice.

Dyes for Water Based Inkjet Inks

It is an important fact that water based ink will accept only dyes that are water soluble. When choosing dyes for water based inkjet inks the choice is a bit limited as the vehicle restricts the types of dyes.

Dyes that are used for water based inkjet inks must provide colors that are highly saturated. Should scatter or refract only a very little amount of light. Various class of dyestuffs has been developed like reactive, direct, acid or base for application in Inkjet Inks.

Water based Ink-jet inks that has good pH stability may be made by using yellow dyes and buffers. Examples can be given of yellow dyes made from water-soluble azo and bis azo dyes. Some of the products in this category are C.I. Direct Yellow 142, C.I. Direct Yellow 86, C.I. Direct Yellow 132, C.I. Direct Yellow 173 etc.
Selecting the Right Dye for water based inkjet inks Inkjet inks are employed for very delicate purposes that requires precision, so the dyes used must be of very high standard and quality. It should show the following qualities:

Excellent tinctorial strength and brilliancy.
Light and water fastness should be high.
Fairly good surface tension.
Protection against gas fade stability.
Extremely low salt content (content with respect to Chlorine, Sulfate, Calcium, Magnesium, pH, solubility, strength and shade).
High purity: The users well understand the critical importance of high purity in inkjet printing. It is pertinent to employ purification techniques that enables to remove inorganic salts along with tracing of filter inks and organics to levels of submicrons. A combination of the following processing technology is a must:
- Reverse osmosis/Ultrafiltration- for removal of inorganic salt.
- Ion exchange - to improving solubility.
- Carbon treatment - that improves surface tension.
- Microfiltration - effective in removal of 99.9% of insolubles.
- Specialized cartridge filtration (low to the level of 0.2 micron) - that can filter out most insolubles.

Other

In water-based inkjet inks there is presence of volatile organic compounds (VOC) and they do have low level of toxicity, the dry rate is relatively slow on the non-absorbent substrates. They often require a special coated media for optimizing dot gain and drying. They also need lamination to secure water resistance. Originally they were developed for the desktop systems only but moved on to facilitate the growth of inkjet in wide-format graphics.

Pigments give environmental friendly products along with durability and better compatibility with packaging. However one thing needs to be specified here is that the colloidal properties generally associated with pigments are more complex than dyes.
Pigments for Water based inkjet printing Inorganic pigments
Inorganic pigments that are used for making printing inks are Carbon Black (very important), Titanium Oxide, Molybdenum Red Pigments and iron Blue all with medium usages while Chromate Pigments (sparingly used).

To make the white inks, the most important inorganic pigment is Titanium dioxide. Another popular inorganic pigment, calcium carbonate is used as an extender to make white inks. But, if we want to make black ink, then the most randomly used inorganic pigment is carbon black.

Organic Pigments
Now a days, the inorganic colored pigments are very rarely used because, these pigments contain very high degree of metallic toxics like chromium, cadmium and lead. In their place to create green and blue shades, phtalocyanine pigments are used. For red and yellow shades inks, Azo pigments are very preferred medium. Whether the molecules of the pigments will absorb light in the visible range or not, depends upon the presence of the conjugated system of double bonds in these molecules.

A few type of Pigments that are used for colored printing inks
Advantages-
Pigments are tiny combinations of a variety of molecules. They are much bigger in size than their dye counterparts. This size advantage translates into:

Lightfastness
Stability
Less susceptibility to environmental factors and oxidising gases.

Downside-
Particles that are found in a dried pigment ink has a surface that is very rough. As a result the light that is reflected of the prints has a predominant tendency toward scattering, giving rise to color that is less saturated and dull.
Recipe for a perfect Pigment Inkjet Ink

100% of water-fastness on any type of media
Excellent color hue and quality for that perfect imaging effect
Excellent light and weather fastness
Particle size below the level of 0.08 micron
No problem of clogging
Quick drying

Dyes in Concrete Industry

Dyes have a special affinity towards concrete, and when used they can result in spectacular effects that is not possible with any other coloring medium. There are a class of dyes that are used in concrete and are collectively known as Concrete Dyes.

They are essentially the water and solvent-based dyes that come in a wide array of colors, and comes with unique qualities. Water based dyes can produce softer hues while bolder hues are possible with solvent based ones. Concrete Dyes as they are called can achieve vibrant tones that is just not possible with stains.
How the Dyes Work Concrete dyes gets packaged in concentrated form. This allows flexibility in the end color. Depending on the nature of application. Concrete dyes can be used full strength or diluted with water or solvents.

Concrete dyes are generally translucent and penetrating color solutions. They are different from acid-based stains, as no reaction takes place between the dyes and the concrete. Instead, the concrete dyes contain minute coloring agents which actually penetrates into the concrete surface. As the image depicts when applied full strength, dyes can produce gorgeous colors, like this border stripe.

Limitations of Concrete Dyes Variations and inconsistent color- A feature that you have to cope up with, even if the dyes are applied in the same surface.

No hiding of the defects- Concrete Dyes, are meant for enhancing rather than camouflaging the surface. They are not supposed to hide cracks, blemishes, or other defects.

Buyer's guide for Concrete Dyes Dyes are more or less permanent colors so before venturing into buying dyes and applying hastily to the surface can result in some situation that could have been easily avoided if some thought was first given to. Here are a few smart tips that will help you in buying these dyes:

What sort of coloring effect that you intend?
As dyes that are used in concrete are packaged in concentrated form (liquid or powder) that gives flexibility in the end color. So you must choose whether to use it in full strength to give depth to color or dilute it with water or solvents for paler shades. There is also another option of blending different dyes to produce custom hues.

What is exactly the condition of the concrete?
Dyes are meant for enhancing the looks rather than disguising the surface. Color effects will usually show greater intensity on new concrete than older or weathered concrete. Contaminants like dirt, grease, sealers, curing compounds, that are found on the concrete surface can easily block or inhibit the penetration of dyes. This can result in washed-out color. So that is the reason why manufacturers insist on the importance of surface preparation.

Can the product be used for both interior and exterior applications?
It is must to consider a dye for an outdoor project, because some dyes are not at all suitable for exterior use because the color may fade away on being exposed to sunlight.

Is it easy for the product to mix and apply?
Dyes can reach you as liquid concentrate or powder that needs to be diluted with a suitable solvent or water before application.

Information on 'coverage rate'
Average is an operative word that is used to assess the coverage rate of a dye. Manufacturers can give you a fixed average range (in units like square feet per gallon), but there is a catch here, they will also state that the rate can change dramatically depending on situations like porosity of the concrete substrate, or the intensity of color.

Paper Industry

Paper Industries are widely using dyes form last so many decades. Seeing the growth in the paper industry it can be safely assumed that Dyes for paper industry has a very promising future. Given below is a comprehensive list of the various grades of paper that are open to dyeing:

Writing and printing paper
Tissue - Facial, toilet, towel, napkin
Copier papers
Boards/Cover papers
Decorative laminated paper
Packaging grades - corrugated case stuff
Envelope grades
Specialty papers like, label, laundry tag, posters

The dyes that are used includes sulphur dyes and cationic direct dyes. Other than these two popular options acid dyes and basic dyes are also used. Sulphur dyes are reduced alkaline solutions. For example to get the colour black, a polymer is obtained by the result of a reaction between. 2, 4 dinitrophenol and sodium polysulphide. The polymer structure is shown below:

Coming to the Cationic Direct Dye, some features which makes them suitable towards use in paper are:

A planar molecular structure
An extended conjugation
An excess of positive charge over the negatively charged surface groups

A typical structure of a cationic direct dye is given here:
Criteria for selection of the Dye

Optimum depth
Clear backwaters
Good affinity
Right shade
Show light fastness
Show bleed fastness
Provides stability to temperature and humidity
Low or no metamerism
Does not affect any other paper chemical/process or parameters
Compliant with regulations in force
Safety in Handling

New Trends appearing in paper dyeing

Trend towards new coloration techniques fueled by pressures of a clearer backwater, pressures from environmental watch dogs and cost of production.
Sophisticated high speed machines are driving the trend of reduction in the use of traditional basic dyes and increasingly giving way to specialty modified Basic and Direct Dyes.
A definite shift to continuous dyeing/size press dyeing.
Newer opportunities propelling new applications like Carbon less papers/Thermal Papers.
Turn to Eco-friendly dyes
- Dyes that are free of harmful amines.
- Dyes that are free of Heavy Metals.
- Certification from ETAD (Ecological and Toxicological Association of dyestuff).
- Dyes that are Biodegradable.

Woodworking Industry

Using dyes in woodworking industry is very common. From finishing for making the stains, to toners that is applied for blending in different species of wood, to make the unmatched colors appear uniform in the same wood. Dyes are also added in coatings for making shading stains, that results in color and coating in one operation. Dyes are also excellent for preparing color touch ups. All in all, the dyes are a versatile colorant which has the capacity to improve and enhance finishing, and restoration operations.

Diagram given below shows some of the most popular combinations of dye colors that are used in furniture:
A: Red mahogany; B: Brown mahogany; C:Dark walnut; D: Medium walnut; E: Red maple; F: Golden oak.
Tips on Selecting the Right Dye Oil Dye- Compared to others the oil dye is slow drying process. Although it allows more open time, but more longer dry time is required.

Alcohol and Lacquer Dyes- These dyes are quite similar to each other. Both has the capacity to dry exceptionally fast. This makes them very difficult to apply by brush or wiping. They give best results when sprayed. Any of of these dyes can be applied to coatings as a transparent shading stain. They do not raise the wood's grain. Generally solvents for these solubles are denatured alcohol and lacquer thinners.

Water type Dyes- It displays the best clarity and is the typically most transparent. Among the dyes used in woodworking it is the most colorfast. One factor that is to be considered here is that as the solvent is water, the dyeing process is very slow. Unlike Alcohol and lacquer dyes, they raises the wood grain.

Dye Color- It would be foolishness to judge dye colors when they are applied, as they are very deceiving to the eye. It is seen that both the powder and liquid stains sometimes appear as one color, but after coating, the colors look quite different.

Color strength of Dyes- It varies from manufacturer to manufacturer. Please be careful about the manufacturer's recommendation, to make sure as to what ratio of dye to the solvent is the right one.

Compatability- There are now a variety of dyes that are available in the market today. Before opting to buy any dye, it is important to determine whether it is compatible when sealed with the coatings. Also, if it can be added to the coating and used for making shading stains. It is also imperative to know how the dye is applied, what solvent is used to dissolve or dilute it and which solvent types quickens or slow down its dry time.

Powder Dyes- Can also be used along with suitable thinners.
Dyes or Pigments: The perennial dilemma

Dyes

Pigments

Dyes are very good for doing touch ups on furniture because of transparency. Dyes do not block out the natural wood, as pigmented colorants generally does if they are not thinned out.

because of transparency. Dyes do not block out the natural wood, as pigmented colorants generally does if they are not thinned out. Pigments has its plus points too, as on some finishes, pigmented colorants are better in matching opaque-colored finishes. Also, pigmented colorants come up with white colors plus a plethora of other colors that can be mixed from them. All in all, there is place in the sun for both dyes and pigments.

Dyes & Pigments in Construction Industry

The different applications of color pigments in the construction industry are as follows:
Paint Analysis
Painting or Paint Analysis is a very common maintenance project in all building, including commercial. Residential and production purposes. By applying a new coat of paint on the walls of the building, one can change the appearance of the entire building. It also brings a new touch of fashion in this regards. Thorough analysis of paint can give the knowledge about the composition of various pigments which are used in the paint.
Paint Analysis
Painting or Paint Analysis is a very common maintenance project in all building, including commercial. Residential and production purposes. By applying a new coat of paint on the walls of the building, one can change the appearance of the entire building. It also brings a new touch of fashion in this regards. Thorough analysis of paint can give the knowledge about the composition of various pigments which are used in the paint.
Increasing The Durability of Buildings When paints are used on the wall, then these paints prevent moisture from entering the walls.
Safety Passage Safety of public buildings is very important, and for this purpose, some safety-way guidance systems have been brought into existence.Under darkness, due to power failure, these materials in the system start to glow brightly. This thing helps the people to find out their rescue way. Generally, these systems are fitted in the safety passages, public buildings, factories, stations & tunnels, ships etc.
Cool Roofing Greater the solar radiation, higher will be the heat absorption by the roofs of the houses. To dissipate the heat, 'Cool Coating' technology has been invented. This new technology focuses on reflecting solar radiation.These pigments are called as Cool Pigments. These pigments are more advantageous than the traditional pigments and they absorb less infrared rays from the sun.
Coating The two type of pigments are used for coating purposes:

Organic Pigments
Inorganic Pigments

Organic pigments gives various bright colors, but, these colors are not very lightfast and opaque as compare to inorganic pigments. Inorganic pigments are used for those applications where color warranty should be there against sunlight and other natural elements. For metal roofing, a special type of pigments are used, which is called as 'Complex Inorganic Colored Pigments'.
Wood Conservation Wooden materials are frequently used in all kind of construction works, right from houses to factories, from bridges to railways. To conserve these wooden materials, some specific kinds of pigments are used.
Concrete Coloring Before the placement of the concrete, pigments are mixed with it to create color. This is the most common method of concrete colorizing. The quantity in which the pigments are mixed and the proportion of their mixing can be altered. By altering these proportion and quantity, the color varieties can be brought in the concretes.
Colored Asphalt Colored asphalt is used in the traffic direction, for sporting facilities, in gardens, at school yards and squares. The color fastness and durability will depend upon the pigments and the proportion in which they are combined with each other.
Cooler Tiles, Metal Panels, and Shingles Pigments are used in various commonly used house-roofing products. These pigments are used in tiles, metals, panels and shingles. Various cool pigments are used today for coating concrete, clay tiles and metal panels.

Dyes in Heat Transfer Printing

The process of heat transfer is faster, durable along with being profitable that is why its gaining recognition from several industries.

The apparel industry has a dedicated use of heat transfer printing technology. They use it as an alternative way for printing fabrics. In this process often the designed gets transferred from a pre-printed paper onto the necessary fabric by the method of contact heat, through which the dyes get absorbed into the fabric. Heat Transfer is good technology for having clear and well defined pictures. This process, called sublimation, needs no water unlike the water requirement in conventional dyeing processes.

The heat transfer printing technology uses dyes for carrying out the printing operations. One of the most popular dye that finds application are the disperse dyes and basic dyes. Azo dyes are also successfully used. Some of the popular disperse dye colors are yellow, orange, red, violet, blue and brown. Ideally disperse type inks that are used in the heat transfer should contain 5-20% by weight of disperse dye.
Basis of selection of the Dyes

Solubility of the dyes in Polymer.
It is very vital that the dye stuffs selected are capable of subliming under heat and pressure conditions. Ideally the dyestuffs should be able to sublime when exposed to temperatures of 140 degree F – 500 degree F for approximately around 10 to 20 seconds.

Heat transfer product applications Some of the popular usages are:

Apparel Industry- Caps, T-shirts, swimsuits, jackets, cut apparel parts, etc.
Plastics- Table tops, counter tops, gaming tables.
Sports Equipment- Snow boards, snow skis, cycling helmets, water sports equipment etc.
Decorative Industry- Ceramic tiles, wall mural, flooring and interior design etc.

Pigments in Paint Industry

Pigments are the coloring elements present in the paints and have a very special place in the paint industry. The paint industry uses specialty pigments to manufacture paints for a variety of applications. Ranging from automobiles to buildings hardware, the list is virtually endless.
The paints that employ the wide variety of pigments can be broadly classified according to application into two types. They are colorants for the industrial applications and architectural/decorative applications respectively.
Pigment Types Earth color Pigment- Derived from the natural sources and are inorganic in nature (i.e. metal oxides). Examples: ocher, umber, terra di siena, bolus, swedish red etc.

Earth pigments have properties like:-

Lightfast
Chemical
Fast weather Resistant

Mineral Pigments- Mineral pigments comprises synthetic inorganic pigments. Examples: chrome oxide green, titanium dioxide, iron oxide yellow, red, brown and black, ultramarine blue, nickel-titanium yellow etc.

One of the disadvantages of mineral pigments is the toxicity and ecological imbalance.

Plant Color Pigments- Plant colors are sourced from natural organic pigment found in plants. Examples: indigo, alizarin red, woad, reseda, alkanna violet and saffron.

Synthetic Pigments- Synthetic Pigments are the most widely used but artificial organic pigments and dyes. Examples are: azo, dioxazine and phthalocyanin.

The advantage is synthesization in almost any shade, especially in pure color tones and gives dazzling visual effects.
What's there in a can of paint? More the amount of pigment and binder, better the quality of the paint.

Paints are manufactured using 4 basic ingredient categories:

Pigments
Binders
Liquids
Additives

Color Tinting System: A New Way to Impart Colors

A total Color Tinting System consists of:

Base paints
Dispenser
Sales aid
Colorants Shaker

Glossary

A
Acid Dye- Applied to polyamide fibres from acidic solutions. Essentially synthetic dyes, they are used for silk, wool and nylon.

B
Basic Dye- Basic dyes are generally cationic dyes. Basic dyes are the dyes that is able to react with acidic groups on fibres.

C
Cation- Known as the positively charged ion. Numerous chemicals applied in textile processing are referred to as cationic.

D
Direct application- A method usually used to describe a process where a solution of dye is locally applied to different areas of fabric, like squirting, painting, spraying, stamping, etc.

E
Enzyme- Enzymes are now popularly used in textile processing. These are the type of protein that perform the role of a catalyst in a biochemical reaction.

F
FBA- Fluorescent brightening agent.

G
Gel Dyeing- A continuous type of tow-dyeing method where soluble dyes are used to wet-spun fibres in the gel state (i.e. After the processes of extrusion and coagulation, but before drying and drawing).

H
Hardness- A measurement that ascertains the content of minerals that imparts specific properties.

I
Illuminating Dye- A dye that is mixed with discharge paste in printing methods also referred to as head dyes.

J
Jet Dyeing- Used in dyeing of Polyester.

K
Kilogram- An unit of mass (weight) in the system of metric. It equals approximately 2.2 pounds avoirdupois.

L
Lake- The pigments that are produced as a result of absorption of the dye on the substrate. Most common substrate can be alumina hydrate.

M
Metal- Complex Dye- A dye that typically has co-ordinated metal atoms in its molecule.

N
Non-ionic - A chemical that does not ionize in a solution while remaining is in intact molecular form some surfactants are non-ionic.

P
pH- A perfect measure of the concentration of hydronium that is found in a solution.

R
Reactive Dye- A dye that, under proper conditions, can react chemically with a substrate for forming a covalent dye-substrate linkage.

S
Sodium Hydroxide- It is a strong base; also called caustic soda or lye, or just "caustic" in dyeing terms. Chemical Formula: NaOH.

T
Tannic Acid- A mixture of compounds derived from natural sources like oak. Tannic acid treatment, followed by a treatment of tartar emetic, has been reported to improve the wash fastness of dyed nylon or wool.

U
Ultraviolet- The light that is beyond the portion that is visible of the light spectrum at the blue end. It is the Ultraviolet light that causes fading of colors, and makes fluorescent compounds glow.

V
Ultraviolet- The light that is beyond the portion that is visible of the light spectrum at the blue end. It is the Ultraviolet light that causes fading of colors, and makes fluorescent compounds glow.

W
Washfastness- Washfastness is used to measure resistance of a dye to washing out.

Y
Yarn Dyeing- Yarn gets dyed before being woven into fabric.

Z
Zinc Formaldehyde Sulphoxylate- A Color Index Reducing Agent 6, used for application in discharge.

What are dyes?

A dye is a natural or an synthetic substance that has an affinity to the substrate to which it is to be applied. It can add a color or can change the color of any substance. The dye is generally applied in an aqueous solution and requires a mordant to improve the fastness of the dye on the fiber.

What is the difference between Dyes and Pigments? Dyes and Pigments have different properties and are used to create different effects.

Both dyes and pigments appear to be colored because they absorb some wavelengths of light more than others. In contrast with a dye, a pigment generally is insoluble, and has no affinity for the substrate. These are mixed with oil, water, etc. to make paint.

What are Natural Dyes? Natural dyes are dyes or colorants derived from plants, invertebrates, or minerals. These dyes are applied on the substances with the help of minerals or metal salts. The metal salts are alum (aluminum salt), iron or tin (called mordants).

Why Use Natural Dyes? The following facts will tell you, why do we use Natural dyes:

Natural Dyes Provide Positive Working Condition:- The working environment with natural dyes is very pleasant. This good working environment is very much conducive for the workers. The non-toxic, no poisonous and pleasant environment makes the working condition positive.
Natural Dyes are no Poisonous in Nature:- Most of the dyes, except Natural dyes are severally poisonous in nature. Due to this thing, when people use these dyes, then there may be a high risk of respiration disturbance of them.
Natural Dyes are Environmental Friendly:- The various wasteful materials which produces during the applications and manufacturing process of synthetic dyes, make the environment poisonous and polluted. So, in this respect also natural dyes are environmental friendly

How do I work out how much dye I'll need? For every 100 gms of fabric weight, 5 gms of dyes should be used. There is a certain method for calculating the required quantity of dyes that has to be used.
Can dark colored items be dyed with pale colors? No, pale colored dyes can not be used for dyeing strong colored substances.

I've stained an item can I hide the stain by dyeing? Yes, one can hide the stain by dyeing because dyes can remove the stains. By coloring the stained area, the stain can be hidden, though this stained area will still look different from rest of the item.

What kinds of dyes are too unsafe to use? The most dangerous kind of dyes are the basic dyes. These dyes have excellent dyeing performance on the acrylic fibers.

What are pigments?

Pigment is the natural coloring matter of animal or plant tissue. Pigments are used for coloring paint, ink, plastic, fabric, cosmetics, food and other materials.

What are hinges? Hinges are made of special archival tape, linen, or fine Japanese paper. With pressure sensitive tapes, prints cannot be glued or taped directly to a backing and for this purpose, hinges are used.

How does particle size affect a pigment's dispersibility? he sizes and shapes of particles of pigments have great impact on the colors of these pigments. But, these pigments are available in cluster form instead of individual form.

What are the lightfast properties of the pigments? The resistance characteristic of pigment against the fading after exposure to sunlight, is called as lightfast property of the pigments.

What are Pigment Sticks? Pigment Stick is an oil stick that transform oil painting into a whole new experience. These sticks consist of linseed oil, natural beeswax, and pigments. Generally, pigment sticks are highly fluid and very smooth.

What is the meaning of Luminescence? Luminescence is emission of light by a substance not resulting from heat; it is thus a form of cold body radiation.

What is the meaning of Fluorescence? Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength.

What is the meaning of Phosphorescence? Phosphorescence is a specific type of photoluminescence related to fluorescence.

What is the meaning of Brightness? Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light.

How does TiO₂ provide opacity? When all of the visible light that falls on a surface, is scattered, then only opacity is appeared. Titanium dioxide is considered as an efficient light scatterer.

What is the relationship between Phosphorescence and Temperature? The light discharged by a phosphor, hugely depends upon the temperature.

Which chemical and physical factors affecting the light fastness of pigments and dyes? The lightfastness of the pigments and dyes do not depend upon the pigment or dye, but depends upon the whole system. These following factors affect the light fastness of pigments and dyes:

Chemical as well as physical structure of these substrates.
The concentration of dyes and pigments.
The rate of diffusion of the volatile substances in the polymer.
Distribution of wavelength of incident radiation.
The atmospheric conditions like the humidity in the atmosphere and percentage of contaminants.
Distribution of wavelength of the incident rays.

What makes one grade of TiO₂ different than another?

The particle size and surface treatment make the grade of TiO₂ different than another.

What are the prescribed directions while using dry pigments? For methods of using dry pigments (or other non-colored powdered additives) which require only as much mixing as is possible with a brush. These methods can be applied for solvent or water-based paints.

Will the organic color pigments stain the clothes or sheets? The color organic pigments are not stains nor these are dyes. So, if some stains arise in the clothes or sheets, then after some time these can be washed-out completely from any synthetic materials.
These stains can be removed very easily.

What is a mixed metal oxide (MMO)? MMO is a kind of inorganic pigment that contain more than one types iron metals in their oxide crystal structure.

Buyers Guide to Dyes

Dyeing is a very critical process and ensuring the quality of dye is also very critical. The warm and moist conditions are also an important factor that should be considered while dyeing any product.

Listed below are some of the parameters and questions that a dye manager must consider before opting for any dyeing process.

Is the process compatible with all the dyes he has opted for
If the process is exactly compatible with the machine with respect to temperature, pH, and material construction and that there is adequate control of these necessary parameters.
The chosen dye gives all the fastness requirements as specified.
Correct dye bath is chosen or not

Common Dyeing Problems
A Dyer encounters a lot of problems while dyeing the products. Here in this page a few of such common dyeing problems as faced by the dyer are discussed along with solutions.
Common Dyeing Problems Solutions Unstable dye dispersion

Select dyes that has better dispersion stability
Application of efficient dispersant

Incorrect dyeing program The answer lies in optimization of dyeing process. Which means adjustment of the process parameters in a manner so that the entire operation takes place in the shortest possible time. It should not exceed the tolerance limits with respect to reproducibility and levelness.

This effectively means quick heating in the temperature ranges where the dye exhausts slowly or is already exhausted. Controlled heating as the dye starts showing a particularly high rate of exhaustion. Poor light fastness Causes are:

Traces of carrier residues on fabric
Staining of adjacent fibre
Catalytic fading because of unsuitable dye combination

Repeat thermofixation (at high temperature)
Selection of appropriate dyes
Adjustment of dye selection

Pale areas found after dyeing is over

Proper ventilation of vapours and gases
Avoidance of contact with dangerous substances

Deviations in shades of dyeing causes can be-

Sensitivity of dyes to hydrolysis, reduction, electrolyte
Sensitivity of dyes to metal ions in the dye bath

Selection of dyes very carefully, exact control of pH
Giving attention to stability of dye with respect to electrolytes

Presence of Precipitates in the dye bath

Causes can include crystallization of dyes due to changes in temperature in the dye bath
Usage of volatile carriers

Using systems that has perfect liquor circulation
Selection of suitable carriers, usage of overhead heating in the machine

Poor dye fixation

This has been a common problem particularly with reactive dyeing when it comes to batch dyeing of cellulose fibres. This can be taken care of by the use of sophisticated molecular engineering techniques. Use of Bi-functional and low-salt reactive dyes can attain more than 95% fixation rate even for cellulosic fibres.
Application of hot rinsing methods.

System losses in continuous dyeing processes

Carrying out of the impregnation step in a nip
The capacity of the dip trough to be minimized.
Separate streams in dispensing the dyestuff and auxiliaries.

Buyer's Guide to Pigments

Pigments find enormous types of application in broad range of industries and encompasses a huge variety of Colorants.
High performance inorganic pigments offer comparatively weak color strength, but can give excellent opacity and durability. To give another example, high cost organic pigments though offer excellent color strength but comes with the limitation of poor opacity. Thus Formulators are left with very difficult choices to make.
Buying Tips
Here are few tips that are valuable in pigment selection:

Selection of Pigment generally is balancing of many types of variables, therefore changes made in the existing commercial formulations should be done judiciously considered and only after color rematching. For example a manufacturer who randomly switches colorant suppliers or reduces expenditure by adopting less costly colorants is under the risk of problems during processing and end-use.
Consideration should be given towards particle size of the Pigment as it affects light scattering, which in turn can affect shading. To cite an example, finer particles has a tendency to shift a red pigment's shade towards blue, while coarser particles tends to move it towards yellower shades.
In the case of application in plastics, adding pigments and dyes asks for matching the right mix of colorants to the shade and intensity of the required colors.
Organic pigments generally can withstand temperatures 400°F and 475°F, while inorganic pigments has been seen to withstand 550°F or even more. In case of some complex inorganic pigments, there is a greater heat stability than some polymers. In case of inorganic pigments like yellow iron oxide, a surface treatment is required to increase their heat stability above 400°F. So, it is imperative that a careful selection of inorganic and organic pigments must be done from the standpoint of temperature so as to maximize color and performance.
It has been seen that in some cases, organic pigments has a tendency to cause part warpage. This generally occurs when pigments interfere with the polymer crystallization. Now the point here is that warpage issues arises more with some kind of pigments than with others. Examples are that of green or blue phthalocyanine pigments. Resins like high-density polyethylene, are more prone to warpage due to their rapid crystallization.
The pigment that is chosen must show compatibility with the base resin so as to prevent a color shift over time.

Important Selection criteria in Pigment applications
Different applications require different sets of properties. The table given below follows some popular applications along with selection criteria for pigments:

Application	Selection Criteria
Metallic/Effect Shade	Transparency- The most significant criteria for the colored pigment in the case of a metallic/effect shade.
Coil Coating	Important criteria for selection are:- Complete hiding Heat resistance Good durability Lightfastness Chemical resistance
Powder Coating	Powder coating can involve complex procedures. Pigment selection among others include: Rheology Hiding Heat stability Dispersability Resistance to wear and tear

Global Dyestuff Industry

A multibillion dollar industry that consists of Dyes, Pigments and Intermediates.

In Global Dyestuff industry, an impressive growth has been seen over the years. This industry includes three sub-segments namely Dyes, Pigments, and Intermediates. The dye intermediates are essential derivatives of petroleum products which after further processing gets transformed into finished dyes and pigments.

The dye and dye intermediaries industry is now an integral part of a huge number of industries. Be it chemical, of which it has a substantial stake, along with that it also provides inputs to a large number of other major industries like textiles, leather, plastics, paints, paper and printing inks, pharmaceuticals to name a few. The following diagram highlights how the Dyestuff industry's interconnection with other facets of the industrial setup:

In 2005, the global market size for dyes, pigments and intermediaries was estimated at around $23 billion. If we see the total volume, then global dyestuff production is estimated to be somewhere around 34 million tonnes. The annual global sales of textile dyestuff alone is estimated approximately around $ 6 billion. One of the major factors that had emerged within the last few years is that the major production centres for dyestuff has shifted from the west to the east. The global dye manufacturing industry originally dominated by suppliers from Europe namely UK, Switzerland Germany, has shifted to Asia over the past 20 years or so. This is primarily because of two reasons. First, due to much lower costs of production in the Asia region. Secondly Asia's growing prominence as the hub for global textile industry.

Major challenges facing by the Global Dyestuff Industry Though an impressive growth has been seen in Global Dyestuff Industry, but still this industry is facing some serious challenges. And these challenges are:

Environmental Considerations- The thrust is now towards the environment friendly natural dyes.

Support of the Government and Trade Association- Any industry that moves ahead needs the back-end support of the government as well as the trade associations.

Problem of over capacity but falling margins- It is a fact that China and India now have high potential as regards production capacity is concerned.

Fierce competition- Again, because of the shift of companies from West to East has resulted in concentration of all the companies in the Asian region which has created intense competition in the global market.

Research & Development- Market demands a higher spending for innovation in products like natural dyes.

Product quality vis-a-vis competitive prices- Manufacturers should focus on the quality of products along with competitive prices for retaining market.

Classification of products and services- A decline in the growth for products has prompted the manufacturers to move to specialty products.

High cost of energy and interest- The exorbitant cost of interest can lower the investment in R&D which is at the core of product and service innovations. Also, the high energy cost has also adversely impacted the manufacturing units.

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