Transcript PRINTING OF COTTON WITH REACTIVE DYES

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
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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
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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
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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 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
PRINT PASTE COMPOSITION
COMPONENT
STEAM
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
DRY HEAT
PAD-BATCH
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