Reactive Dyes

Reactive Dyes are the most versatile and popular class of Organic Dyes for importing color on cellulosic fibres. As the name suggests, these dyes chemically react with cellulose to form a covalent bond between dye molecule and cellulose. Reactive site on dye reacts with functional group on the fibre to bind dye covalently under influence of heat and proper pH. Reactive dyes are unique as they are the only class of dyes that actually form a chemical bond with the textile fiber and this bond gives them their excellent wash fastness properties. Reactive dyes are used to cotton Rayon wool silk & Nylon.

Print Paste Recipe
10 parts	Titanium Dioxide (1.1)
10 parts	Citric Acid
1 part	Optical Whitening Agent
20 parts	Water
	Balance Thickening
100 parts

Print with resist paste-overprint with Kevizol print paste containing alkali. Dry-steam either in Rapid Ager or in Star Ager at atmospheric pressure for 5-7 minutes or 15-20 minutes respectively. Wash off in neutral detergent at boil

Cold Pad - Batch Dyeing

Pad at 20-30°C
Dyes	Titanium Dioxide (1.1)
Urea	Citric Acid
Sodium Sillicate	Optical Whitening Agent
Caustic Soda	Water
Glauber's Salt
Temperature
Batching
Wash off	Balance Thickening
Pick up
Cotton	Woven 65-80%, Knit 80-110%
Viscose Rayon	70-90%

Behaviour of Keviactive using Sodium Silicate

Keviactive Reactive	Solubility in Presence of Alkali			Stability at 30°C
Keviactive Reactive	Without Urea	With Urea	With Urea	Stability at 30°C
	g/I	100g/I	200g/I	Minutes
Yellow FG	100	-	-	30
Yellow GR	100	-	-	60
Red 58	60	-	-	120
Rubine CB	100	-	-	30
Violet 5R	75	-	-	60
Blue 3R	100			60
Blue R	100	150	150	60
Turq. Blue PG	75			120
Brown GR	100	-	-	120
Black B	100	-	-	45

Soaping

Drop Dyebath
Minutes
10	Rinse cold
10	Rinse cold
15-30	Soap at the boil
10	For heavy shades rinse warm (50°C)
15	Rinse cold until clear and soften if required drop bath and unload

Thorough wash and efficient soapping is very vital to get optimium fastness

General Properties


Light fastness (Day Light) ISO 103-B01-1998	1 to 8 increasing order
Washing and other fastness	1 to 5 increasing order
Dischargeability	A - White Discharge B -Moderaterly Dischargeable C -Non Dischargeable
Stain	Staining on adjacent White fabric

Key to Abbreviations


Y - Yellow	L - Low	Substantivity or Reactivity on unmercerised cotton
G - Greener	M - Medium
R - Redder	H - High
Br - Brighter	B1 - Blackish
D - Duller	LS - Less Suitable
Sr - Stronger	NS - Not Suitable
W - Weaker	S - Suitable

(On bleached mercerised cotton) Kevizol dyes applied by Cold Pad Batch method