Post on 02-Jan-2016
description
PIGMENT PRINTING
DIFFERENCE BETWEEN DYE AND PIGMENT
PIGMENT
• NO AFFINITY TO FIBRE
• INSOLUBLE IN WATER
• NEED BINDER FOR FIXATION ONTO FIBRE
DYE
• AFFININTY TO FIBRE
• WATER SOLUBLE OR CAN BE MADE WATER SOLUBLE. EXCEPTION DISPERSE DYE
• HELD ON FIBRE DYE-FIBRE INTERACTIVE FORCES
BINDER
• IT IS PRE-POLYMER AVAILABLE IN THE FORM OF AQUESOUS EMULSION
CHEMICAL NATURE
COPOLYMER OF STYRENE-BUTYL ACRYLATE-N-METHYLOL ACRYL AMIDE
MECHANISM OF BINDING
SEQUENCE
PRINT > DRY > CURE
• DURING CURING: BINDER POLYMERISES AND FORMS A STRONG FILM
• BINDER FILM EMBEDES PIGMENT COLOUR AND ALSO STRONGLY ADHARES TO THE FIBRE
CHOICE OF THICKENER
• CONVENTIONAL THICKENER USED FOR DYE PRINTING ARE NOT SUITABLE
• THEY INTERACT WITH BINDER AND REDUCE ITS INTERATION WITH FIBRE. THUS AFFECTING THE FASTNESS PROPERTIES
SUITABLE THICKENERS
• EMULSION THICKENER – ZERO SOLID CONTENT THICKENER
• SYNTHETIC THICKENER - VERY LOW SOLID CONTENT THICKENER
EMULSION THICKENER
• OBTAINED BY EMULSIFICATION OF TWO IMMISCIBLE LIQUIDS WITH THE HELP OF EMULSIFIER
TWO TYPES
• OIL-IN-WATER EMULSION
• WATER-IN-OIL EMULSION
• COMMONLY USED IS OIL-IN-WATER
PREPARATION OF OIL-IN-WATER EMULSION
BINDER 100 PARTS
WATER 100-150 PARTSEMULSIFIER 20 PARTSUREA 20 PARTSCMC (4-6% PASTE) 10 PARTSKEROSENE OIL 750-800 PARTSMINERAL TURPENTINE OIL
• VERY SLOW ADDITION OF OIL• CONTINUOUS HIGH SPEED STIRRING
• EMULSIFIER: REDUCE SURFACE ENERGY BETWEEN OIL AND WATER• UREA: HYGROSCOPIC AGENT, MINIMIZE WATER EVAPORATION IN
CONTINUOUS PHASE• CMC: PROTECTIVE COLLOID
EMULSION THICKENER
MERITS• IDEAL FOR PIGMENT PRINTING
DEMERITS• INFLAMMABLE- FIRE HAZARDS• AIR POLLUTION• HIGH COST• FABRIC SMEES DUE TO RESIDUAL k.OIL OR
MTO. NOT ACCEPTABLE IN EXPORT MARKET
SYNTHETIC THICKENER
CHEMICAL NATURE
• HIGH MOL.Wt. COPOLYMERS OF ACRYLIC OR METHACRYLIC ACID
• HAVE FREE –COOH GROUPS ON POLYMERIC CHAINS WHICH A ROLE IN VISCOSITY BUILD UP
• TRADE PRODUCTS: AQUEOUS EMULSION, ACID pH
• CONCENTRATION FOR PRINTABLE VISCOSIT 1-2%
MECHANISM OF THICKENINGSYNTHETIC THICKENER IN ACID FORM
WATER INSOLUBLE, LOW VISCOSITY, NON-IONIZED –COOH GROUPS
SYNTHETIC THICKENER IN NEUTRIZED FORM
WATER SOLUBLE, SWELLABLE, HIGH VISCOSITY
IONIZED –COOH GROUPS
SYNTHETIC THICKENER
MERITS
• NO AIR POLLUTION• NO RISK OF FIRE AND EXPLOSION• NO SPECIAL STORAGE REQUIREMENTS• NO FABRIC SMELL
DEMERITS• ELECTRLYTE SENSITIVITY• SLIGHTLY DULL PRINTS AND HARSH
FABRIC FEEL• LONGER DRYING TIME
PREPARATION OF THICKENER PASTE
BINDER 100 PARTS
WATER 80-890 PARTS
SYNTH. THICKENER 10-20 PARTS
LIQUOR AMMONIA TO pH 8
PRINT PASTE COMPOSITION
PIGMENT COLOUR X PARTS
THICKENER PASTE TO MAKE 1000 PARTS
DIAMM. PHOSPHATE 10 PARTS
MELAMINE FORMALDEHYDE 10 PARTS
SEUENCE
PRINT > DRY > CURE AT 140-1500 C FOR 4-5 MIN.
NO WASH