Basic dye application in textile industry.pptx

Brief discussion on basic dyes

1. Basic dye Submitted by Aryadip Dey University Roll no. - 1100120029 6 th Sem, Textile Technology Govt. College of Engineering & Textile Technology, Serampore

2. Introduction Basic dyes are called so since they are salts of organic bases . They are also known as cationic dyes because of the presence of positive charge in the dye molecules under dyeing conditions. During dye application, the negatively charged acrylic fiber attracts the positively charged dye cations for ionic bonding. Due to high attraction between the oppositely charged fiber and dye molecules, there is risk of unlevel dyeing because of high rate of dyeing. This risk may be reduced by careful control of dyeing temperature and used of suitable retarding agents .

3. Classification The conventional basic dyes belong to several chemical classes, such as: Diphenylmethane or ketone imine (presence of C=NH group), e.g. C.I. Basic Yellow 1. Triphenylmethane, e.g. C.I. Basic Red 9 (Para Rosaniline ), and C.I. Basic Violets 3 (Crystal violet) and 14 (Fuchsine). Thiazine (nitrogen and sulphur atoms forming a ring with benzene carbons), e.g. C.I. Basic Blue 25 (New methylene blue H) and C.I. Basic Green 5 (Methylene Green). Oxazine, similar to thiazine, but nitrogen and oxygen atoms form a ring with benzene carbons, e.g. C.I. Basic Blue 12 (Nile Blue).

4. Classification (Continued) Azine, similar to thiazine, but two nitrogen atoms form a ring with benzene carbons, e.g. C.I. Basic Red 5 (Neutral Red). Xanthene (two benzene rings linked by oxygen atom and methylene bridge) derivatives, e.g. C.I. Basic Red 3 (Rhodamine 3G). Acridine (two benzene rings linked by a nitrogen atom and –CH= group) derivatives, e.g. C.I. Basic Orange 14 (Acridine orange). Azo groups, e.g. C.I. Basic Brown 1 (Bismarck Brown).

5. Properties The outstanding characteristics of the basic are brilliance and intensity of their colors. The basic dyestuff are most commonly used for dyeing polyacryonitrile or acrylic materials. The basic dyestuff will combine with direct dyes or  sulphur dyes or some acid dyestuffs. So they cannot be used together in the same bath. But basic dyestuffs are used in after treating cotton or other materials dyed with direct colors. Here the direct dyestuff acts as mordant.

6. Properties (Continued) Many of the basic dyestuffs are sparingly soluble in water. Basic dye is readily soluble in alcohol or mentholated spirit. The basic dyestuffs are poor fastness to light and vary with regard to washing fastness from poor to moderate. Basic dye can be removed from the material by boiling it with dilute acetic acid or hydrochloric acid.

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

8. limitations Poor shade stability High acid content Colored backwaters Very poor lightfastness Preferential dyeing

9. Application of the Basic Dyes Basic dyestuffs are extensively used for dyeing of jute, cut flowers, dried flower, coir, etc. For dyeing Acrylic fibers, basic dye are used widely. Modified basic dye is used for dyeing of Acrylic fiber, because these are perfect for this material. If the reason behind the success of Basic dyes is analysed , it would be seen that the positively charged cations of the Basic dyes gets attracted towards the negatively charged anions in the acrylic fiber. Acrylic polymers have anionic groups attached to it. They are most commonly the sulphonate group, –SO3−, followed closed by the carboxylate group, –CO2−. This reaction of the cation and anion results in salt linkages.

10. Application of the Basic Dyes (Continued) Basic dye does not show absolutely any migration in acrylic fibers under normal dyeing conditions. Basic dyestuffs are also preferred to dye leather, because they can get combined easily with vegetable-tanned leather thus doing away with mordant. Basic dyes are also used in the coloring of papers. Basic dyestuffs for paper widely used in textile industries. Its application is similar to that of direct dyes but requires different and more precise controls with auxiliaries and temperature.

11. Thank You