Difference between Direct, Acid & Basic Dye |

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 a strong affinity towards the fiber which can be applied directly on the fiber and does not need any assistance.

Acid Dye:

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

Basic Dye:

Basic dye is usually ionic in nature but not like direct or acid dyes. Basic dyes generally produce two types of ionizers. 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 and basic Dye:

The Differences between Direct, Acid and 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 an acid or alkaline or neutral medium.	Dyeing is done in an acid medium.	Dyeing is done in a neutral medium.
04	Color Forms	Forms colored anion and colorless cation in solution.	Forms colored anion and colorless cation in an aqueous solution.	Forms colored cations and colorless anions in an aqueous solution.
05	Affinity	Direct dye has a direct affinity to cellulosic fibers.	Acid dye has a 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.

Noor Ahmed Raaz

Founder & Editor of Textile Merchandising. He is an Assistant Professor and Chairman of the Textile Engineering Department of a Reputed University in Bangladesh. He has performed numerous Research Regarding Textile Engineering. He has also received two times “Research & Development Fellowship” from the Ministry of Science & Technology in Bangladesh. For any further queries, please contact email at raju.uttara105@gmail.com or WhatsApp at +8801673758271.