PRINTING OF COTTON WITH REACTIVE DYES

CO-VALENT BOND FORMATION BETWEEN DYE AND FIBRE

REACTIVE DYES BASED ON• SUBSTITUTION REACTION

REACTIVE DYES BASED ON SUBSTITUTION REACTION

• DEVELOPED BY ICI IN 1956• MARKETED UNDER THE TRADE NAMES• PROCION M• PROCION H• COLOURED DERIVATIVES OF 2,4,6

TRICHLORO-S-TRIAZINE OR CYNURIC CHLORIDE

PROCION DYES

• PROCION M DYES (COLD BRAND)• DICHLORO TRIZINE

• PROCION H DYES (HOT BRAND DYES)• MONOCHLORO TRIAZINE

DYES BASED ON ADDITION REACTION• DEVELOPED BY HOECHST

• MARKETED UNDER TRADE NAME REMAZOL

• REACTIVE GROUP VINYL SULPHONE

• COMMERCIALLY AVAILABLE IN THE FORM BETA SULPHATOETHYL SULPHONE

• DYE REACTIVITY

PROCION M > REMAZOL > PROCION H

DYE REACTION WITH CELLULOSE AND WATER

CHOICE OF THICKENER

THICKENERS FOR DYES OTHER THAN REACTIVE AND PIGMENT COLOURS

• CARBOHYDRATES OR MODIFIED CARBOHYDRATES HAVING PRIMARY OH GROUPS IN THEIR STRUCTURE

• NOT SUITABLE FOR PRINTING COTTON WITH REACTIVE DYES

• SELECTED THICKENER SHOULD BE FREE FROM PRIMARY OH GROUP

SODIUM ALGINATE

• MOST SATISFACTORY THICKENER• SODIUM SALT OF ALGINIC ACID

DOES NOT REACT WITH REACTIVE DYE• ABSENCE OF PRIMARY REACTIVE GROUP• REPULSION BETWEEN COO – OF

THICKENER AND SO3 - GROUP OF DYE

PRINTING

FABRIC PREPARATION• PREFERABLY MERCERIZED• SHOULD BE NEUTRAL OR SLIGHTLY

ALKALINE

DYE DISSOLUTION• PRINTING NEEDS CONCENTRATED

SOLUTION• UREA ACTS AS DYE DISSOLVING

ASSISTANT AND HYGROSCOPIC AGENT

DYE DISSOLUTION

TWO PROCEDURES

1. PASTE DYE POWDER WITH COLD WATER. ADD HOT WATER. THEN ADD UREA

2. MIX DYE POWDER AND UREA. ADD HOT WATER

HOT WATER TEMPERATURE• COLD BRAND DYES 60-700 C• HOT BRAND DYES 800 C

PRINT PASTE PREPARATION

DYE FIXATION METHODSSTEAMING PROCESS

PRINT > DRY > STEAM > WASH > SOAP > WASH > DRY• ALKALI IN PRINT PASTE

STEAMING • ATMOSPHERIC STEAMING• TEMPERATURE 1020 C• TIME : COLD BRAND 5 MIN., HOT BRAND 15 MIN.

DRY HEAT PROCESSPRINT > DRY > CURE > WASH > SOAP > WASH > DRYCURING: 140-1500 C FOR 5 MIN.

SODIUM SILICATE PAD-BATCH METHODPRINT > DRY > SODIUM SILICATE PAD-BATCH > WASH > SOAP > WASH >

DRYSODIUM SILICATE 1000 TWBATCHING TIME 4-12 Hr. ROOM TEMPERATURE

PRINT PASTE COMPOSITION

COMPONENT STEAM DRY HEAT PAD-BATCH

DYE 10-40 gm 10-40 gm 10-40 gm

UREA 50 gm 150-200 gm 50 gm

WATER 150-200 ml 150-200 ml 150-200 ml

RESIST SALT 10-20 gm 10-20 gm NIL

SOD. ALGINATE PASTE (4%)

TO MAKE 1000 gm

TO MAKE 1000 gm

TO MAKE 1000 gm

SOD. BICARB. 10-20 gm 10-20 gm NIL

ROLE OF UREA IN DRY HEAT FIXATION

• HIGH CONCENTRATION OF UREA 150-200 gm/kg OF PRINT PASTE

• WATER EVAPORATION DURING DRYING• NO WATER AT THE TIME OF FIXATION AT 1500 C• NO IONIZATION OF DYE AND CELLULOSE• NO DYE FIXATION• UREA MELTS AT 1320 C• PROVIDE MOLTEN BATH AT PRINTED PORTION AT

FIXATION TEMP.• DYE DISSOLUTION AND FIBRE SWELLING IN

MOLTEN UREA• FACILITATE DYE FIXATION

SOAPING

AFTER FIXATION DYE PRESENT ON FABRIC

1. DYE REACTED WITH FIBRE

2. DYE REACTED WITH WATER (HYDROLYZED DYE)

3. DYE STILL IN REACTIVE FORM

OPTIMUM WASH FASTNESS DEPEND ON EFFICIENT REMOVAL OF 1 AND 2

SOAPING MOST IMPORTANT OPERATION

SOAPING

• COLD WATER WASH, AMPLE WATER, 2-3 RINSES

• SOAPING AT BOIL USING 2 g/l LISSAPOL D (ANIONIC DETERGENT) FOR 15 MIN.

• HOT WATER RINSE• COLD WATER RINSE• PRECAUSTION: TO AVOID STAINING OF

WHITE, SOAPING IN OPEN WIDTH FORM ON 6-8 COMPARTMENT OPEN SOAPER