Difference between Direct, Acid & Basic Dye

By | January 31, 2017

Difference between Direct, Acid & Basic Dye

Rana Sohel
Production Officer (Dyeing)
Sunman Textile Mills Ltd. Chittagong
Cell: +8801912-420118
Email: rsohel07tex@gmail.com

 

Direct Dye:

Direct dyes are anionic dyes having substantivity for all types of cellulosic fibers. Direct dye has strong affinity towards the fiber which can be applied directly on the fiber and which do not need any assistance.

Acid Dye:

Acid dyes are mainly sodium salts of sullphonic acid but there are a little containing Carboxylic groups. The acid dyes have a direct affinity towards protein fibers and poly amide fibers.

Basic Dye:

Basic dye is usually ionic in nature but not like as direct or acid dyes. Basic dyes generally produce two types of ionizes. They are colored cations and colored anions. The colored portion of basic dye is prepared from free of subtracted amino group. Such as, -NH2, -N (CH3)2, -N (C2H5)2 etc.

Dyeing Process

Difference between Direct, Acid & Basic Dye:

The Difference between Direct, Acid & Basic Dye are given below-

S/L
Subject
Direct Dye
Acid Dye
Basic Dye
01
Azo Group
Dye
molecules contain more than one azo group.
Dye
molecules contain only one azo group.
Dye
molecules contain no azo group but substitute amino group.
02
Size of dye molecule
Here,
size of dye molecule is big.
Here,
size of dye molecule is small.
Here,
size of dye molecule is smaller than that of direct dye.
03
Medium
Dyeing
is done in acid or alkaline or neutral medium.
Dyeing
is done in acid medium.
Dyeing
is done in neutral medium.
04
Color Forms
Forms
colored anion and colorless cation in solution.
Forms
colored anion and colorless cation in aqueous solution.
Forms
colored cations and colorless anion in aqueous solution.
05
Affinity
Direct
dye has direct affinity to cellulosic fibers.
Acid
dye has direct affinity to protein fibers.
Basic
dye has no direct affinity to cellulosic or protein fibers.
06
Washing Fastness
Here,
washing fastness is about 2-3.
Washing
fastness is about 2-5 according to leveling property.
Washing
fastness is about 4-5.

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