Finishes are applied to enhance the performance of a fabric
There are finishes applied to fabrics to enhance the look and feel of the fabric, in other ways the finishes neither strengthen the quality of the fabric nor they are done to transform the fabric for special purposes such as the fire retardant finish.
Once a fabric has been produced, it often goes through a finishing process to improve its appearance and/or properties. The main types of finishes are as follows:
- Physical – where a machine or tools is used to change the fabric
- Chemical – where chemicals are used to change the fabric
- Biological – where bacteria and enzymes are used on cellulose-based (Plant-based) fibres
- Coated – where the fabric is coated on one side with a substance (such as Teflon, to repel staining).
Why the Fabric Finish required
Finishes have been developed to improve the fabric in many ways such as:
- Enhance appearance – colour, pattern, sheen
- Change texture – embossing, brushing, smoothing
- Improve feel – softer, crisper, firmer
- Improve drape – weighted
- Modify wearing qualities – crease resistance, stain resistance, flammability, waterproof, etc.
- Modify care requirements – easy wash, quicker drying times, colourfast, less shrinkage
Finish Processes and Properties
The following gives some common fabric finishes and their properties as a guide to fabric choice.
Fabric softening is generally done together with de-sizing (de-size means to de-starch) and pre-shrinking. When de-starching is done softener is added to make the fabric soft and smooth. This process is indispensable for the fabric to be used to make garments without pre-washing. Whenever too much softener is used to finish the fabric, the stability of the colour may be weakened resulting in lower colour crocking standards.
Brush and Sanding Finish
In many cases, we may finish the fabric by brushing or sanding to give them to smooth velvet –like or suede-like surface. The difference between brushing and sanding is:
- Brushing – the hair is long and the fabric is fluffy
- Sanding – short hair feels like suede
For better results we should handle brushing in the following manner:
- For solid colour fabrics, we should brush first and then dye and brush them one more time. If we dye them first and then brush you will get a frosted effect (with a cast of white colour mixed in the solid colour) because the fibre in the centre of the yarn where the dye could not fully penetrate into may come to the surface to make the fabric to look frosted.
- For printed fabrics, we should brush first and then print because of the following reasons:
- If you print first and then brush, the printed area may not become as haired or fluffy as the white area or the un-printed area because the dye (particularly pigment-dye) covers the fabric like a shield and keeps the fibre down.
- If the fabric is printed with reactive dye making the printed area almost as soft as the unprinted area, then the above phenomenon may not appear, but the coloured hair or fibre form the printed area may overlap the un-printed side distorting or spoiling the printed design. If you brush first and then print, the above problem will not emerge.
Mercerizing and Singeing Finish
Singeing and mercerizing are in many cases related and done at the same time. Singeing is passing the fabric through a flame (fire) so that the hair and nubs of the fabric are burnt off to give it a clean surface. This is commonly done on most cotton fabrics including denim. It consists of the burning of fuzz on the fabric surface. Before singing the cloth is brushed to remove the loose fabric and also to remove the dust. The fabric is kept flat under tension and passed rapidly over an open gas flame. Later it is passed into the water to cool down.
Mercerizing means treatment by soaking the fabric into caustic soda to give a shine to it. This process is not done on denim because it will hurt the colour of indigo or sulphur. However, it is mostly done on grey goods or dying or dyed goods which have a colourfast quality.
Chintz finish is usually applied on TC CVC or cotton poplin to give it a glossy finish. Sometimes we call it oil finish. This is strictly a fashion.
Peach Skin Finish
Peach skin is a smooth finish applied to finely woven Micro Fiber fabric. The soft, suede finish are the results of sanding or chemical treatment of the fabric. This finish allows suits and dresses to flow with movement and drape beautifully. The feel of peach skin is soft, smooth and moderately wrinkle-resistant. It is a medium weight fabric that has a fuzzy, suede-like feel.
Engraved rollers create a relief pattern on the fabric. Texture and appearance change due to pattern embossed as a result.
Heavy rollers press the surface of the fabric. The fabric is smoother and has improved sheen as a result.
Presses smooth the surface of the fabric. There are improved handle and a smoother surface; pressing is often used on wool fabrics.
The fabric is steamed and placed over a vibrating conveyer belt. This reduces further shrinkage later (in use and care)
Silicone is sprayed on to the fabric surface. Droplets of water remain on the surface; air can pass through. This is not waterproofing and fabric will let water through if saturated.
Stain-resistant resins are applied to the surface of the fabric. Dirt is prevented from clinging to the surface as a result.
Resins are applied to the fabric. Fabrics become crisper but crease less as a result.
Chemicals are applied to yarn or fabric. This prevents fabric from easily igniting.
Fibre scales (found on wool) are removed with chlorine, or resins block scales. Shrinkage in washing is reduced as a result; used in wool products.