Textile wet processing can be thought of having three stages, pretreatment (or preparation), coloration (dyeing or printing) and finishing. Finishing is the final step in the fabric manufacturing process, the last chance to provide the properties that customers will value. It is also called the beautification process of fabric. Finishing completes the fabric’s performance and gives it special functional properties including the final ‘touch’.
Chemical finishing can be defined as the use of chemicals to achieve a desired fabric property. Chemical finishing, also referred to as ‘wet’ finishing, includes processes that change the chemical composition of the fabrics that they are applied to. In other words, an elemental analysis of a fabric treated with a chemical finish will be different from the same analysis done prior to the finishing.
The finishing processes may be broadly classified into two groups:
- Physical or mechanical finishing
- Chemical chemical finishing
In this article, I only describe on chemical finishing of textiles.
Chemical finishing or ‘wet finishing’ involves the addition of chemicals to textiles to achieve a desired result. Physical properties such as dimensional stability and chemical properties such as flame retardancy can both be improved with chemical finishing. Normally, the appearance of the textile is unchanged after chemical finishing.
The proper formulation of chemical finishes is not easy. Several important factors are to be considered before the finalisation of a formulation; a few are as follows:
- The type of textile (fibre composition of the fabric and its construction)
- The performance requirements (extent of effect and durability)
- The economics of the formulation
- Availability of machinery and associated process restrictions
- Procedure requirements
- Environmental consideration
- Compatibility and interactions of finishing components.
Chemical finishes should meet the following requirements:
- Low-cost product and process
- Stable during storage and application in terms of pH, temperature and mechanical stress
- Compatible with other finishes
- Adaptation to customer requirement and substrate variation
- Suitable for all kind of fibres and all textile forms such as yarn, woven or knit fabric, garment, nonwovens, etc.
- Satisfactory stability during washing and dry cleaning
- Should not hamper important textile qualities
- On application should be distributed evenly on the fabric and fibre surface
- No yellowing of white goods or colour change of dyed goods.
- Easy correction of finishing faults
- Nontoxic and ecofriendly
- No release of volatile organic compounds
List of chemical finishing used in textile industry:
- Stiffening / Hand-building
- Easy-care, Wrinkle Recovery and Durable Press Finishing
- Water Repellent Finishing
- Stain Resistance Finishing
- Soil Release Finishing
- Flame Retardant Finishing
- Anti-microbial Finishing
- Moisture Management Finishing
- Anti-static Finishing
- Optical Brightening
Importance of chemical finishing in textiles:
Chemical finishing has always been an important component of textile processing, but in recent years the trend to ‘high tech’ products has increased the interest and use of chemical finishes. As the use of high performance textiles has grown, the need for chemical finishes to provide the fabric properties required in these special applications has grown accordingly.
The amount of textile chemical auxiliaries sold and used globally in one year is estimated to be about one-tenth of the world’s fiber production. With fiber production currently at 60 million tonnes, about 6 million tonnes of chemical auxiliaries are consumed. The percentage of textile auxiliaries used in different process is shown in above Fig. About 40 % of textile auxiliaries are used in finishing, the largest percentage usage of all textile chemicals, followed by dyeing and printing auxiliaries and pretreatment chemicals.
- Principles of Textile Finishing by Asim Kumar Roy Choudhury
- Chemical Finishing of Textiles by Peter J. Hauser and Wolfgang D. Schindler
- Textile Engineering – An Introduction Edited by Yasir Nawab
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.