Presentation outline

INTRODUCTION

FUNCTION

MECHANISM

CHEMISTRY OF DURABLE PRESS FINISH

Formaldehyde cross linking agents or resin

Non-formaldehyde cross linking agents or resin

Miscellaneous cross linking agents or resins

METHOD OF APPLICATION

The pre cure process

The post cure process

The immersion process

garment process or product process

Metered addition process/ Vapor phase process

Durable press in wool

Durable press in silk

Coneprest process

Advantages in durable press with corresponding suitability

Disadvantages of permanent press finish with possible remedies

Major trademarks of durable or permanent press finish

Quality performance standards and care

Health hazards

Test for crease resistance in textile

Test for permanent press finish in fabric

Test for the presence of formaldehyde in sample

INTRODUCTION

Permanent press forms an essential part of easy to care finishes or resin

finishes which are anti crease finish, wash and wear finishes, durable

press finishes and soil release finishes.

Durable press or permanent press finishes are required to provide

pressed-in creases and stop formation of sharp creases during ironing.

The creases formed should last daily wash care routines

The technically correct name for such finishes is ‘cellulosic anti-swelling’

or ‘cellulosic cross linking’ or ‘resin finish’

FUNCTION

To incorporate easy care feature in cotton, linen and

regenerated cellulose materials so that they do not require

frequent ironing as this finish keeps them free from creases.

To incorporate required/necessary

crease in garments along with

crease resistance finish.

cause of formation of creases are:

Swelling due to moisture absorption

Bending

Folding

Pressing

MECHANISM

CREASE RETENTION THEORY

Crystalline and amorphous regions are bonded by hydrogen bond

hydroxyl group in amorphous region approach other hydroxyl group and when they come close to each other they get bonded by hydrogen bonds again

newly formed bonds prevent unfolding of fabric and a crease is formed

Bending, folding, pressing or swelling produces stress

some of the hydrogen bonds at the boundary of the amorphous and crystalline region breaks as such bonds are fairly weak

Hot ironing

Prevention of Hydrogen bond

Formation by blocking the

hydroxyl group

Removal of hydroxyl group

to prevent formation of

Hydrogen bond

METHODS TO REMOVE CREASES

The finish is imparted in following two ways namely:

EXTERNAL

Incorporation of polymerized

finish in the porous structure of

fiber so that water penetration

is blocked.

INTERNAL

Reaction of cross linking agent

with hydroxyl group of adjacent

cellulose molecule

CHEMISTRY OF DURABLE PRESS FINISH

CROSS LINKING AGENTS

The cross linking agents are

resins which are applied in the

form of solutions on viscose are

called precondensates.

Produce full, soft and supple hand.

Gives permanent and more

precisely durable finish.

Absorption and adsorption

Glass resin finish

Petroleum resin

Polyester resin

Polyester resin

Terpene resin

It’s never done with the help of gums or starches.

Raspberry gum Edible starches

FORMALDEHYDE RESIN

Urea-formaldehyde (U/F) Melamine-formaldehyde (M/F) N,N’-dimethylol-4,5-dihydroxyethylene

urea (DMDHEU)

NON-FORMALDEHYDE RESINS

N,N’-dimethyl-4,5-dihydroxyethylene urea

(DMeDHEU) 1,2,3,4- Butanetetracarboxylic acid

CLASSIFICATION OF CROSS LINKING AGENTS

di methylol ethylene or

propylol urea di glyoxal urea triazons urons carbamates di epoxides di so cyanates

MISCELLANEOUS CROSS LINKING AGENTS

saturated with resins, thermoplastic polymers etc..

Dried

Heat curing

The most common method for application of permanent

press finish is pad-dry-cure.

METHOD OF APPLICATION

Resin coating on fiber glass cloth

Saturate the fabric with

resin cross linking solutionDry

Cut, sew and pressCure in a curing oven to form cross links

between molecular chains.

Shirting, draperies, cotton/polyester blends.

THE PRE-CURED PROCESS

SUITABILITY:

slacks, skirts, cotton/polyester blends.

THE POST-CURED PROCESS

Saturate with resin cross linking solution

Cut and sew items

Cure the pressed item in a curing oven at 300 to 400°F

press shape with

Hot-head press

Dry

SUITABILITY:

Fashion apparel of 100% cotton.

THE IMMERSION PROCESS, GARMENT PROCESS or PRODUCT DIP PROCESS

Dry

Cure in curing oven at 300°F for 5 to 15 minutes

Press desired features into garment with special hot head press

Modify hand andperformance

Immerse product or garment in finishing

agent

SUITABILITY:

Spray product with finishing agent and continue tumbling

Modify hand and performance

Press desired features with

special hot head press.Cure in curing oven at 300°F for

5 to 15 minutes

Fashion apparel of 100% cotton.

METERED ADDITION PROCESS

SUITABILITY:

Dye and finish the productPress desired features with special

hot head press

Modify hand and performanceApply finish in vapor form to the

product in a chamber and cure it.

Cotton and other natural fibers.

VAPOR PHASE PROCESS

SUITABILITY:

APPLICATION METHED

ADVANTAGE DISADVANTAGE

Pre-cure High process productivity

Poor crease retention

Post-cure Excellent crease retention

Garment manufacturer need to keep curing equipment

Garment padding Softest handle Garment manufacturer need to keep application (padding) and curing equipment

SUMMARY

DRY CURING WET CURING

It needs less time. The time needed is comparatively more.

It requires high temperature. It require low temperature.

Loss of tear strength and abrasion resistance

Good tear strength and abrasion resistance

High dry crease recovery angle.

Lower dry crease recovery angle.

Lower wet crease recovery angle.

High wet crease recovey angle.

DURABLE PRESS IN WOOL

Durable press finish is imparted to wool to provide good resilience when it is wet and also to control shrinkage. The wool finishing process is as follows:

.

Flat fabric treated with 1 to 2 % of durable press resin

steamed for 3 to 5 minutes

sprayed with more durable press resin

pressed to achieve a permanent crease effect.

shrink resistant resin is mixed with dry cleaning solvent and dry-cleaned

resin is cured in item for 3 to 7 days before being laundered.

DURABLE PRESS SILK

Since silk wrinkles easily when wet, permanent press finish is imparted for better appearance

Poly carboxylic acid is used as resin to give the required finish.

CONEPREST PROCESS

It’s a trademark of Cone Mills which has been accepted as the name of a finish by virtue of its long use.

It’s the process by which pre cured fabrics are made into garments.

Where creases are desired a substance is sprayed to temporarily inactivate the crease

resistance finish.

After setting the crease the garment is pressed under pressure to reactivate the finish.

ADVANTAGES OF PERMANENT PRESS WITH CORRESPONDING SUITABILITY

EFFECT SUITABLE TEXTILE

Easy care and wrinkle resistance woven

Dimensional stability Knitwear

Durable press Formal and leisure wear with some

demand, plisée/pleated goods

Pile resilience – improved pile

stand by better elastic resilience

Pile fabrics

Sheen and wash permanence of

chintz

Calendared (chintzed) fabric

Permanent knitter (hand knitted) look –

retention of irregular creases and

wrinkles

Crushed fabric, a fashion trend similer

to used look

Antipilling Knitwear of 100% cellulose

Fixation of other finishes (eg –

stiffening with water soluble hand

builders)

Fabric with low warp end filling

densities, knitted dress fabric, denims,

awnings, mattress duck etc.

Fixation of dyestuff and pigments Cellulosic with direct and acid dyes,

pollycotton with reactive dyes, heat

transfer printing of cellulosics.

DISADVANTAGES OF PERMANENT PRESS FINISH WITH POSSIBLE REMIDIES

GENERAL DISADVANTAGES POSSIBLE REMEDY

Loss of abrasion, tear and ripping

strength

Wet condensation; liquid ammonia

treatment, addition of silicones, PVA

etc.; polyurethane

Hard handling Combination with softeners

Graying during washing Combination with soil release finish

Less dilatable and elastic Combination with silicones, eg

elastomers.

CASE WISE DISADVANTAGES POSSIBLE REMEDY

Release of large amount of formaldehyde Formaldehyde-free or low formaldehyde

finish

Reduction of light fastness Selection of appropriate dyestuff, cross

linkers and catalysts

Shade change of dyed fabric Selection of appropriate dyestuff, cross

linkers and catalysts

Yellowing in case its not dyed or

fluorescent brightened

Selection of appropriate catalyst,

fluorescent brightener and application

condition.

Objectionable odours, sometimes fish

smell

Selection of catalyst (no ammonium

product), cross linkers, if necessary

washing.

Chlorine retention, causing marked

yellowing and strength loss

Selection of cross linking agents, use of

chlorine free washing

TRADEMARK MANUFACTURER

ALMI- set Amritex Div. Of United Merchants And Manufacturers,

Inc

Lifetime pressed Amritex Div. Of United Merchants And Manufacturers,

Inc.

Coneprest Cone Mills

Dan press Dan Mills

Koratron Koratron Co.

Penn Press J. C. Penny Co.

Perma Press Sears Roebuck & Co.

Press Free Cotton McGregor

MAJOR TRADEMARKS OF DURABLE OR PERMANENT PRESS FINISH

QUALITY PERFORMANCE STANDARDS AND CARE

General care guidelines are as follows for permanent press items:

Wash items frequently because resins have a strong affinity for oil and grease easily penetrates and builds up

Pretreat stains, collars, and cuffs by use a spot removal agent.

Keep wash loads small to minimize wrinkles

Avoid setting in wrinkles with heat, keep washing and drying temperatures cool.

HEALTH HAZARDS

Formaldehyde used mostly for durable press finish is not good for health because:

More than 1 ppm of formaldehyde causes a pungent odor (threshold detection level by smell is 0.5 ppm).

It irritates mucous membrane, causes teary eyes, induces cough and can lead to difficulties in breathing.

Skin contact with aqueous solution of formaldehyde or with textiles that contain a high level of formaldehyde can give rise to eczema and occasional allergic reactions.

It is a suspected human carcinogen.

TEST FOR CREASE RESISTANCE

The most common method which is as per standards and specifications is ISO2313 test.

This crease recovery test can be carried with fabric while in dry and as well as in wet stage.

The finish is called crease resistance in case the crease recovery angle is 180° or more along with a shrinkage of usually less than 5%.

Cut ten warp and weft wise samples going diagonally on fabric

Fold sample horizontally and keep pressed between two acrylic sheet templates under 1 kg

load for 5 min

Put the sample on graduated machine to measure angles of recovery of crease while maintaining required temperature and

pressure

The major steps for crease resistance test are as follows:

TEST FOR PERMANENT PRESS FINISHES IN FABRICS

It’s done with the help of AATCC 88C test method.

it tests retention of crease in fabric after repeated home laundering.

The fabric with set in crease are washed and dried by specified procedures.

The crease appearance is compared to standards on 1-5 scale.

TEST FOR PRESENCE OF FORMALDEHYDE IN FABRIC

The qualitative test method for the presence of free formaldehyde in a fabric sample is as follows:

piece of fabric added to 2-3 ml of chromotropic acid or 100 ml of 72% sulphuric acid.

solution is heated carefully to not more than 100° C for 1 min

A red or violet colour in the solution indicates the presence of formaldehyde.

BOOKS:

Finishes/ Finishing Process Understanding Fabric

Chemical Technology Of Textile Fiber

Chemical Finishing Of Textiles

Textiles- Sara J. Kadolph Anna L. Langford

Understanding Textiles- P. G. Tortora

Textile finishing- R.S. Prayag