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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
E N D
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
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 • PASTE DYE POWDER WITH COLD WATER. ADD HOT WATER. THEN ADD UREA • MIX DYE POWDER AND UREA. ADD HOT WATER HOT WATER TEMPERATURE • COLD BRAND DYES 60-700 C • HOT BRAND DYES 800 C
DYE FIXATION METHODS STEAMING 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 PROCESS PRINT > DRY > CURE > WASH > SOAP > WASH > DRY CURING: 140-1500 C FOR 5 MIN. SODIUM SILICATE PAD-BATCH METHOD PRINT > DRY > SODIUM SILICATE PAD-BATCH > WASH > SOAP > WASH > DRY SODIUM SILICATE 1000 TW BATCHING TIME 4-12 Hr. ROOM TEMPERATURE
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 • DYE REACTED WITH FIBRE • DYE REACTED WITH WATER (HYDROLYZED DYE) • 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