What is Textile Finishing Process?
The textile finishing process is a combination of a series of processes that are applied to gray fabric to enhance its good outer appearance, and good hand feel, possibly adding new properties. Basically, the term “finishing” includes all the treatments applied to gray fabrics such as de-sizing, scouring, bleaching, dyeing, or printing. But, the term “functional finishing” includes some mechanical or chemical process applied on dyed or printed fabric to add some new special properties (water repellency, flame retardancy).
Objectives of Textile Finishing Process
- Textile finishing process is carried out to free from hairiness of the fabric.
- Finishing process increases the attractiveness of the fabric.
- Another crucial objective is to increase the fineness and ensure smoothness of fabric.
- To increase attractiveness to the fabric paying customers.
- To ensure the softness of the fabric.
- To improve the functional finishing of the fabric.
Types of Textile Finishing Process
Mainly, there are two types of textile finishing process available used in textile industry. They are:
- Mechanical finishing process
- Dry finishing
- Calendering
- Embossing
- Sueding
- Raising
- Singing
- Wet finsing
- Wet calendaring
- Fulling
- Sanforising
- Decating
- Dry finishing
- Chemical finishing process
- Softening
- Anti-static treatment
- Anti-mildew treatment
- Flame retardant
- Water-resistant
- Antislip finishes
- Light stabilizing finishes
- Pilling resistant finishes
1. Mechanical Finishing Process
The mechanical finishing process relates to the application of physical principles( such as temperature, pressure, friction, tension, and others) on the fabric. Thus, functional properties develop on the fabric. Some important mechanical finishing process is described below.
Calendaring
Calendering is a non-permanent finishing process. it is applied to fabrics made of cellulose, protein, and synthetic fibers. Generally, the calendaring finishing process includes one or a series of couples of rollers pressed one against the other with adjustable pressure and identical or similar tip speeds. The fabric is passed through one or more couples of rollers, which exert a smoothing action, and a pressing action. A lustrous, dense, and compact appearance of fabric can be obtained by using friction, pressure, and heat.
Different effects is obtained by using different types of calendars. To cite an example:
- Sheen appearance: Sheen appearance can be obtained by using smooth cloth surfaces, that ensure a better reflection of light.
- Yarn swelling and rounding effect: they give a modest glaze finish to the fabric, a surface smoothness, and above all a full and soft hand.
- Surface patterns: This effect can be obtained using special effects (embossing). It is used for decorative purposes or to modify the surface smoothness.
- Soften hand: Soften is obtained owing to a slight ironing effect, which produces a smoother, and softer cloth surface.
Embossing:
Embossing is one kind of calendaring process. But the difference is that, in the embossing process a simple pattern is engraved on the cloth. The embossed roller is made of steel, and it is pressed against another roller coated with paper or cotton. A gear system drives the harmonized motion of the rollers, preventing them from sliding and granting a sharp engraving of the patterned design. After being engraved, the pattern can be established using an appropriate high-temperature treatment.
Sueding
Sueding operation is often carried out before the raising process to reduce the friction between the fiber making up the cloth and consequently to facilitate the extraction of the fiber end. The sueding process is carried out on both sides (face and back) of the fabric. This process modifies the appearance and final hand of the cloth, when touched it gives a soft and smooth sensation similar to the one given by a peach grain surface.
Raising or brushing
This is a very old technique. Raising operation is particularly suitable for wool and cotton fabrics, it gives a fuzzy surface by abrading the cloth and pulling the fiber end to the surface. By the using of raising process, a hairy surface can be given to both faces of the fabric. This process modifies the fabric’s appearance, softer, fuller, and bulk increase. Thus, the resistance of the textile materials to atmospheric agents is increased, by improving thermal insulation and warmth provided by the insulating air cells in the nap. The fuzzy surface is created by pulling the fiber end out of the yarns using metal needles provided with hooks shelled into the rollers that scrape the fabric surface.
Sanforizing
This process produces greater density and stability and gives the fabric a controlled compression shrinkage, which eliminates distortions that originated during the previous process. The fabric finished with this treatment keeps its shape also after repeated washing thus providing an excellent dimensional stability of the textile substrate.
Decating
Decating process is mainly carried out on wool by exploiting its elastic properties in hot and wet conditions by the direct action of the steam on the fabric. Decating treatment gives the processed fabric the following characteristics:
- Pre-stabilization to autoclave dyeing
- Dimensional stability
- Decating process reduction of possible glazing effect after calendaring, thanks to the swelling caused by steam blown on fibers.
2. Chemical Finishing Process
In the chemical finishing process, some special chemicals is used to modify the functional properties of textile products. The chemical finishing process also called the functional finishing process that are applied to the fabric to enhance performance in a specific area. Some important functional finishing process is given below.
Softening
Generally, each fiber has its specific softness value, which depends on its chemical composition and physical structure ( less crystallinity = greater softness). The fineness of the fiber or the filament directly affects the softness of the yarn. There are a relation between twist ratio and softness i.e. the yarn twist ratio is inversely proportional to its softness. Softeners or enzymes are used in the softening process.
Anti-static treatment
Wool and manmade fibers (nylon, acrylic,and polyester) develop static electricity from the friction caused by wearing and general use. Therefore, the fabric attracts dirt particles, clings and climbs, and even spark. Some companies do apply antistatic treatments, sometimes in combination with other finishes that may have antistatic components in them.
Antistatic finishes work by
- Improving the surface conductivity so that excess electrons move to the atmosphere or ground.
- Attracting water molecules to increase fiber conductivity.
- The fiber’s electrostatic charge is neutralized by developing an opposite charge.
Most finishes use quaternary ammonium compounds, which are not durable and must be replaced during care. Washing aids such as fabric softeners help control static. Some trade names of antistatic nylon variants are Ultron, Antron, Staticgard, and Anso.
Anti-mildew treatment
Certain ambient conditions can permanently damage cellulose. In addition to depolymerizing cellulose or feeding on it, certain microorganisms can cause cellulose to become permanently damaged. Starch finishing agents can worsen the situation during long storage periods. If you use antiseptics or bacteria-controlling products, this damage can be prevented. Antiseptics and bacteria-controlling products contain quaternary ammonium salts and phenol derivatives.
Flame retardant treatment
Flame retardant treatment helps to reduce the flammability of fabric. Flame retardant treatment is applied to the textiles to resist fire, slow its speed, and stop burning.
Water-resistant treatment
Water resistant treatment makes the surface of fabric resistant to water by causing water to bead up and roll off instead of being absorbed.Compounds that make fabric water resistant include fluorocarbons, wax emulsion, metallic soap, and surface active agents.
Antislip finishes
Antislip finishes are used on low count , smooth surfaced fabrics. When fabrics are treated with resins, stretched, and dried under tension, the yarns are bonded at their interlacing points. Antislip finishes reduce seam slippage and fraying. Antislip finishes are also called slip resistant, or nonslip, finishes. The most effective and durable finishes are resins of urea or melamine formaldehyde.
Light stabilizing finishes
Light stabilizing finishes incorporate light-stabilizing or ultraviolet-absorbing compounds to minimize damage from light exposure. This is important for furnishings and industrial products. Products that are exposed to sunlight or interior lighting that has a high percentage of ultraviolet light may require this finish.
Pilling resistant finishes
Pilling resistant finishes minimize the possibility that tiny balls of fiber bits will accumulate on a fabric’s surface. The fabric is exposed to short wavelength ultraviolet radiation and then immersed in a mild oxidation solution. Surface fiber ends are thus weakened and much less likely to form pills. This experimental finish, Siroflash, is used on wool and cotton blends.
References
- Belal, P. D. (2016). Understanding Textiles for a Merchandiser. Dhaka: L.B Graphics and Pringing.
- Kadolph, S. J. (2006). Textiles. New Delhi: Pearson Education.
- Chawla, K. (1998). Fibrous Materials. Cambridge: Cambridge Univ. Press.
- Corbman, B. P. (1987). Textile Fiber to Fabric. Singapore: McGraw Hill Book Co.
- Hossain, M. F. (2015). Practice of Textile Coloration, Volume-I. Dhaka: Books Fair Publications.
- Hossain, M. S. (2014). Introduction to Textile Engineering. Dhaka: Books Fair Publications.
