Introduction Of Finishing And Resin Finishing email@example.com By Aravin prince I M.Tech ( Textile Technology)
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 firstname.lastname@example.org 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
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. email@example.com After finishing only the steps of inspection and packing are left to make the fabric ready for shipment or marketing.
FINISHING GIVES THE FOLLOWING ADVANTAGES: Improved appearance – luster ,whiteness etc., Improved feel which depends on the handle of the fabric and its softness, suppleness, fullness etc., It improves the wearing qualities – Non soiling firstname.lastname@example.org anticrease. It gives special properties required for particulars uses – 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 before they are put on the market.
CLASSIFICATION TEXTILE FINISHINGCHEMICAL MECHANICAL email@example.comREACTIVE TYPE DEPOSITION TEMPORARY PERMANENTOF FINISH TYPE OF FINISH E.g. Calendaring Eg.Raising, SanforisingParchementising TEMPORARY PERMANENT(Stiff& Transparent) Starch E.g., Synthetic resinChlorination 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 AcetateFormaldehyde cellulose ether (stiff)(Soil release)Phosphorous&Nitrogen compounds(Flame retardant)All are permanent
Finishing Is Commonly Divided Into Two Categories Chemical Mechanical.Chemical FinishingIn chemical finishing, water is used as the medium for firstname.lastname@example.org applying the Chemicals.Heat is used to drive off the water and to activate the chemicals. Resin treatment Softener treatment Powder Coating Soil/Stain Resist Fire/Flame retarding Special Purpose
Mechanical FinishingIt is considered a dry operation even though moisture and chemicals are often needed to successfully process the fabric. Calendaring Pitching/Raising Sanforising email@example.com Heat settingType Of Finish (Durability) Finishing mainly falls into three groups; 1. Temporary finish 2. Permanent finish 3. Semi-permanent finish
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 firstname.lastname@example.org 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.
Contd… Obviously Resin Finishing is the process of bringing out a special property of „crease recovery‟ to Cotton. Resin finishing often known by various fancy terminology is an important process of textile processing. email@example.com 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
Contd… firstname.lastname@example.org Resins are cross linking agents, which form covalent bond on reaction with –OH groups of cellulosic materials in acidic medium at a pH of 3-4.
RESINS MAINLY FALL INTO TWO GROUPS Deposition type of resins Cross linking type of resinsDeposition type of resinsThis type of resins is deposited on the fabric as email@example.com 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
Cross Linking Type Of Resinso These types of resins chemically react with the fiber and cross link the fibre molecules.o The type of finish obtained is durable and much better than deposition type.o They are also known as N – Methylol compounds as the Methylol groups (-CH2 OH) are attached to the nitrogen. firstname.lastname@example.org The cross linking compounds are commonly called resins, but the term pre condensate is correct. The pre condensates further polymerize to form resins.The following are some of the cross liking agents mostly used 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
ObjectiveThe main objective of resin finish Keep the fabric flat and smooth and Free from undesirable creasesAdvantages It improves the Crease Resistance and Crease Recovery property email@example.com 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
Disadvantages firstname.lastname@example.org 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
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. email@example.comCotton 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.
MECHANISM OF CREASING Why do some fabrics wrinkle and others dont? 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 firstname.lastname@example.org 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.
MECHANISM OF CREASING The inner polymer chains are under compressive stresses – also providing lateral forces. Under stress, the hydrogen bonds between email@example.com 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.
THEN HOW TO MAKE COTTON CREASE RESISTANT ?It is clear now that the weak Hydrogen bonds gets disturbed during the course of washing and on drying they try to rearrange and reform giving rise to creases.From the mechanism of creasing either we have to firstname.lastname@example.org Prevent disortion of hydrogen bonds. Make cotton rigid- which for obvious reasons not recommended. Make cotton Elastic- which for obvious reasons not feasible.Therefore the only way left out will be to prevent disortion of Hydrogen bonds which is being perfectly carried out by means of BLOCKING the Hydrogen bonds forming groups by means of cross linking of –OH groups of cellulosic chains.
CATALYSTS Various Catalysts have been suggested and reported in literature which exhibits their own influence on the fixation of resin and in turn on the CRA. email@example.com The catalysts mainly are Acid liberating agents which liberates the required acid by decomposition during curing process and thus maintains the pH. Of the various catalysts, Magnesium Chloride, Di- Sodium Hydrogen Phosphate, Di-Sodium Di- Hydrogen Phosphate, etc are popular. For commercial purposes Magnesium Chloride is only used from the cost point of view. Even though differences in the CRA obtained are reported with different catalysts usage in the padding liquor, commercially they are not much important.
RESIN CONCENTRATION As the concentration of resin increases in the pad bath the CRA of the resultant product increases. firstname.lastname@example.org Dry Crease Recover y (w+d) Degress Reagent Concentration (Mole x 102 / 100G Fabric)
EFFECT ON PHYSICAL PROPERTIES email@example.com
EFFECT ON PHYSICAL PROPERTIES CRA VS CURING TEMP. & RESIN TYPE firstname.lastname@example.org
EFFECT ON PHYSICAL PROPERTIES email@example.com
COMMON CATALYSTS FOR PAD-DRY-CURE AND FLASH- CURE FINISHING PROCESSES 1.Ammonium salts : eg- NH4Cl (Ammonium Chloride) 2.Amine salts: eg- HOCH2CH2NH2.HCL firstname.lastname@example.org 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)
PROCESS SEQUENCEPad email@example.comDryCure Wash
CONDITIONS OF APPLICATIONPadding At Room Temperature 75-80% Wet Pick Up firstname.lastname@example.orgDrying Temperature - 100-1100CCuring 1500C For 3 Min
DURABLE PRESS FINISH Woven fabric is padded with 250 gpl resin along with necessary additives, dried and email@example.com 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.
QUALITY CONTROL METHODSEstimation of Wet Pick Up of ResinUnfixed Resin content firstname.lastname@example.orgCRANumber of cross links formed by chromatographyLoss in Tensile StrengthLoss in Tear StrengthBreaking Load at ElongationEffect on Whiteness Index for full bleached
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