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
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