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Introduction Of Finishing And Resin Finishing By Aravin prince I M.Tech ( Textile Technology) [email protected]
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Introduction Of Finishing
And Resin Finishing
By
Aravin prince
I M.Tech ( Textile Technology)
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INTRODUCTION& IMPORTANCE OF
FINISHING
The ultimate aim of a finishing process is to develop
and or modify the fibers or finishes for conventional
synthetic fibers so that they give the comfort of
natural fibers , the richness of animal fibers
A finishing process in which a desired quality or
qualities are imparted to fabric in order to improve the
appearance, to affect stiffness, weight, elasticity, or
softness, to facilitate care, or to protect the wearer.
Examples include calendaring, durable press
finishing, water and oil repellency, and softening
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CONTD…
As the name implies, it is the last step or the process
in the method of conversion of fiber into fabric
which is in the marketable or useable form.
After finishing only the steps of inspection and
packing are left to make the fabric ready for
shipment or marketing.
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FINISHING GIVES THE FOLLOWING
ADVANTAGES:
Improved appearance – luster ,whiteness etc.,
Improved feel which depends on the handle of thefabric and its softness, suppleness, fullness etc.,
It improves the wearing qualities – Non soilinganticrease.
It gives special properties required for particularsuses – water proofing, Flame proofing etc.,
It covers the faults of the original cloth
It increases the weight of the fabric
It increases the sale value of the material.
It improves the serviceability of the fabric.
Hence finishing is essential for a textile good beforethey are put on the market.
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CLASSIFICATION
TEXTILE FINISHING
CHEMICAL MECHANICAL
REACTIVE TYPE DEPOSITION TEMPORARY PERMANENT
OF FINISH TYPE OF FINISH E.g. Calendaring Eg.Raising,
Sanforising
Parchementising TEMPORARY PERMANENT
(Stiff& Transparent) Starch E.g., Synthetic resin
Chlorination of wool China clay (Crease resistance, Wash
(Antishrink) (Stiff) & wear Durable press)
Mercerizing Oils, Fats & China clay (Stiff)
Velan Pf waxes (soft) Rubber coating
(Flame retardant) Optical (water proof)
Ethylene oxide- brightening Cellulose Acetate
Formaldehyde cellulose ether (stiff)
(Soil release)
Phosphorous&
Nitrogen compounds
(Flame retardant)
All are permanent
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Finishing Is Commonly Divided Into Two
Categories
Chemical
Mechanical.Chemical Finishing
In chemical finishing, water is used as the medium forapplying the Chemicals.
Heat is used to drive off the water and to activate thechemicals.
Resin treatment
Softener treatment
Powder Coating
Soil/Stain Resist
Fire/Flame retarding
Special Purpose
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Mechanical Finishing
It is considered a dry operation even though moisture
and chemicals are often needed to successfully
process the fabric. Calendaring
Pitching/Raising
Sanforising
Heat setting
Type Of Finish (Durability)
Finishing mainly falls into three groups;
1. Temporary finish
2. Permanent finish
3. Semi-permanent finish
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RESIN FINISHING
Cotton is mainly selected for apparel purpose because of its
durability, ability to withstand the rough laundering treatments
especially under alkaline conditions, good perspiration absorption
characteristics, and comfort during wear and ability to take up a
wide range of dyestuffs.
However, proneness to creasing under slight crushing and retention
of the crease for a long time give cotton garments a poor rating
during actual wear.
The ability of a fabric to resist the formation of crease or wrinkle
when slightly squeezed is termed as crease resistance.
The ability of a fabric to recover to a definite degree is called crease
recovery of the fabric.
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Contd…
Obviously Resin Finishing is the process of bringing out aspecial property of „crease recovery‟ to Cotton.
Resin finishing often known by various fancy terminology is animportant process of textile processing.
Resin finishing quite often called
“ Wash & wear finish”“Anti crease finish”
“Crease resistant finish”“Durable press finish”
And “ wrinkle free finish”
is gaining importance today
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Contd…
Resins are cross linking agents, which form covalentbond on reaction with –OH groups of cellulosicmaterials in acidic medium at a pH of 3-4.
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RESINS MAINLY FALL INTO TWO GROUPS
Deposition type of resins
Cross linking type of resins
Deposition type of resins
This type of resins is deposited on the fabric as
surface coating. No reaction will take place
between the fiber and resin. They include
Phenol-Formaldehyde resins
Urea formaldehyde resin
Alkyd resins
Ketone resins
Vinyl resins
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Cross Linking Type Of Resins
o These types of resins chemically react with the fiber andcross link the fibre molecules.
o The type of finish obtained is durable and much better thandeposition type.
o They are also known as N – Methylol compounds as theMethylol groups (-CH2 OH) are attached to the nitrogen.The cross linking compounds are commonly called resins,but the term pre condensate is correct. The precondensates further polymerize to form resins.
The following are some of the cross liking agents mostlyused for crease resistant finishing.
DMU (Dimethylol Urea )
DMEU (Dimethylol Ethylene Urea)
DMDHEU (Dimethylol Dihydroxy Ethylene Urea)
DMPU (Dimethylol Propylene Urea)
TMM ( Trimethylol melamine/ Melamine formaldehyde
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Objective
The main objective of resin finish Keep the fabric flat and smooth andFree from undesirable creases
Advantages
It improves the Crease Resistance and Crease Recovery property
It reduces the shrinkage of the fabric during laundering
It imparts a smooth and quick drying property
It improves Resilience, Handle and Draping quality
It improves the weight and Dimensional stability
It increases the strength of RAYONS in both wet and dry state
It gives resistance to degradation by light and laundering
It improves the fastness to Light and Washing of many dyestuffs
It prevents the Inter molecular slippage in the fiber core
It becomes partially water proof and Rot proof
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Disadvantages
It decreases the Tensile strength and Tear strength
It decreases the Abrasion resistance
It gives an unpleasant odor
It gives unwanted Harsh and Stiff feel
It turns the fabric yellow after chlorine bleaching
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WHY COTTON FORMS CREASES ?
We also understand that Elastic materials like rubber do not form
creases.
We know that rigid materials like metals do not form creases.
Cotton is not
* RIGID and therefore bends and the deformation results in as
CREASE
* ELASTIC and therefore can not regain its original shape and
position after deformation.
* It is clear that when a load is applied on cotton material, since it is
not rigid will bend and deformation that takes place results in as
CREASE and since cotton is not a elastic material it can not regain
its original shape and position and hence the deformation that
resulted remains as SET CREASE.
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MECHANISM OF CREASING
Why do some fabrics wrinkle and others don't?
Close examination of this question reveals a relationship
between moisture absorption and wrinkling. Wool and cotton
fabrics wrinkle, both fibers absorb water. Polyester and nylon
fabrics are more resistive to wrinkling, they absorb much less
than the other two.
To understand wrinkling of cellulose fibers, consider the stress
and strain forces within the cellulosic chain.
The stretching stresses a t the outer reaches of the bend
provide lateral forces to adjacent polymer chains which can
cause them to move.
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MECHANISM OF CREASING
The inner polymer chains are under compressive
stresses – also providing lateral forces.
Under stress, the hydrogen bonds between
adjacent cellulose chains can break allowing the
chains to slip past each other.
New H-bonds can form as the hydroxyl groups re-
associate with different partners.
Having done so, there are no forces to pull the
neighboring chains back to their former position.
The stressed shape of the fiber is just as stable
now as was the original shape.
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THEN HOW TO MAKE COTTON
CREASE RESISTANT ?
It is clear now that the weak Hydrogen bonds gets disturbedduring the course of washing and on drying they try torearrange and reform giving rise to creases.
From the mechanism of creasing either we have to
Prevent disortion of hydrogen bonds.
Make cotton rigid- which for obvious reasonsnot recommended.
Make cotton Elastic- which for obviousreasons not feasible.
Therefore the only way left out will be to prevent disortion ofHydrogen bonds which is being perfectly carried out bymeans of BLOCKING the Hydrogen bonds forming groupsby means of cross linking of –OH groups of cellulosicchains.
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CATALYSTS
Various Catalysts have been suggested andreported in literature which exhibits their owninfluence on the fixation of resin and in turn on theCRA.
The catalysts mainly are Acid liberating agentswhich liberates the required acid by decompositionduring curing process and thus maintains the pH. Ofthe various catalysts, Magnesium Chloride, Di-Sodium Hydrogen Phosphate, Di-Sodium Di-Hydrogen Phosphate, etc are popular. Forcommercial purposes Magnesium Chloride is onlyused from the cost point of view. Even thoughdifferences in the CRA obtained are reported withdifferent catalysts usage in the padding liquor,commercially they are not much important.
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RESIN CONCENTRATION
As the concentration of resin increases in the pad
bath the CRA of the resultant product increases.
Reagent Concentration
(Mole x 102
/ 100G Fabric)
Dry
Crease
Recover
y
(w+d)
Degress
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COMMON CATALYSTS FOR PAD-DRY-CURE AND FLASH-
CURE FINISHING PROCESSES
1.Ammonium salts : eg- NH4Cl (Ammonium Chloride)
2.Amine salts: eg- HOCH2CH2NH2.HCL
3.Organic acids : eg- HOCH2COOH (Per Acetic acid)
4.Metalic salts : eg- MgCl2 (Magnesium Chloride)
5.Dual and complex catalyst system :
eg- MgCl2 +NaBF4
(Tetra Fluoro sodium bromide)
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CONDITIONS OF APPLICATION
Padding
At Room Temperature
75-80% Wet Pick Up
Drying
Temperature - 100-1100C
Curing
1500C For 3 Min
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RECIPES
DMDHEU - 70 Gpl
Catalyst - 7 Gpl
Silicone
Emulsion - 10 Gpl
P. E - 10 Gpl
Acetic acid- 1 Gpl
Anti Stat* - 1 Gpl
DMDHEU - 125 Gpl
Catalyst - 15 Gpl
Silicone
Emulsion - 15 Gpl
P. E - 15 Gpl
Acetic acid- 1 Gpl
Anti Stat* - 1 Gpl
DMDHEU - 225 Gpl
Catalyst - 25 Gpl
Silicone
Emulsion - 25 Gpl
P. E - 25 Gpl
Acetic acid- 1 Gpl
Anti Stat* - 1 Gpl
Wash & Wear
Resin Finish Wrinkle Free
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DURABLE PRESS FINISH
Woven fabric is padded with 250 gpl resin
along with necessary additives, dried and
the fabric is converted into garment form and
actual curing is carried out followed by a
cold wash and soaping to remove the unfixed
resin.
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QUALITY CONTROL METHODS
Estimation of Wet Pick Up of Resin
Unfixed Resin content
CRA
Number of cross links formed by chromatography
Loss in Tensile Strength
Loss in Tear Strength
Breaking Load at Elongation
Effect on Whiteness Index for full bleached
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“ DREAMS MAKE THOUGHTS
THOUGHTS MAKE THINGS
THINGS MAKE WONDER ”
