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

THICKENERS FOR DYES OTHER THAN REACTIVE AND PIGMENT COLOURS 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

PRINT PASTE PREPARATION

DYE FIXATION METHODS STEAMING PROCESS SODIUM SILICATE PAD-BATCH METHOD 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

PRINT PASTE COMPOSITION COMPONENT STEAM DRY HEAT PAD-BATCH DYE 10-40 gm UREA 50 gm 150-200 gm WATER 150-200 ml RESIST SALT 10-20 gm NIL SOD. ALGINATE PASTE (4%) TO MAKE 1000 gm SOD. BICARB.

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

AFTER FIXATION DYE PRESENT ON FABRIC 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