Basic dye is a stain that is cationic (+ve charged) and so will react with material that is (-ve) negatively charged. This dye is usually synthetic, that act as bases, and which are actually aniline dyes. Their color base is not water soluble but can be made so by converting the base into a salt. The basic dyes, while possessing great tinctorial strength and brightness, are not generally light-fast.

At the chemical level, basic dyes are typically cationic or positively charged. Basic dyes display cationic functional groups like -NR3+ or =NR2+. Since basic dye is a stain that is cationic or positively charged and it is the reason that it reacts well with material that is anionic or negatively charged.

Basic dyes consists of amino groups, or alkylamino groups, as their auxochromes. Synthetic dye that was discovered by Perkin incidentally was a basic dye. Few examples of basic dyes are the following, methylene blue, crystal violet, basic fuchsin safranin, etc. An example of a basic dye that has amino groups as their auxochrome is pararosanilin or basic red 9 (according to the strict color index system of classification) example of alkylamino groups is methylene blue or basic blue 9. Basic Blue 9 is a very popular dye that has vast use. Table given below provides more information about Basic Blue 9:



A basic chemical structure of Basic Blue 9

 

Advantages of Basic Dyes

• Moderate substantivity
• Relatively economical
• High Tinctorial strength
• Wide shade range
• Shows good brightness
• Includes some of the most brilliant synthetic dyes

 

Limitations of Basic Dye

• High acid content
• Colored backwaters
• Poor shade stability
• Preferential dyeing
• Very poor light fastness

 

Modified Basic DyeModified basic dyes have similar chemistry, as of basic dyes. These only show a bit longer molecular structures than the typical conventional basic dyes, thus resulting in significantly improved properties.

Key advantages over conventional basic dyes:-

• Better Lightfastness
• Clear backwaters
• Covers all fibres
• Excellent substantivity