PIGMENT PRINTING

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

MERITS AND DEMERITS

• PRACTICALLY ALL TYPES OF FIBRES AND BLENDS CAN BE PRINTED

• PIGMENT COLOURS CAN BE READILY MIXED WITH EACH OTHER TO GET QUICK SHADE MATCHING

• NO AFTER TREATMENT SUCH AS WASHING, SOAPING REQUIRED

DEMERITS

• HARSH FABRIC FEEL DUE TO BINDER FILM

• LOW RUBBING FASTNESS