Textile finishing

Textile Fabric Finishing:

In order to impart the required functional properties to the fiber or fabric, it is customary to subject the material to different type of physical and chemical treatments. For example wash and wear finish for a cotton fabric is necessary to make it crease free or wrinkle free. In a similar way, mercerising, singeing, flame retardant, water repellent, water proof, antistatic finish, peach finish etc are some of the important finishes applied to textile fabric.

Functional Finishes:

The properties of synthetic fibers, most important among them being polyamide, polyester and 

polyacrilonitrile, are essentially different from those of natural cellulosic and wool fibres. Hence the sequence of finishing operations is likely to be different. While cellulosic's require a resin finishing treatment to impart easy-care properties, synthetic fibers already have these easy-care criteria and require only a heat setting operation. The use of 100% synthetic textiles has increased considerably since the arrival texurised yarns consisting of filaments and the growing production of knit goods. The use of open weave has enabled production of lighter, air permeable, fabrics to ensure better wearing comfort.

Finishes for Natural Fibers:

Mercerisation: This is a process to make cotton fiber - stronger, more lustrous and functionally to have more dye pick up, less abrasive and so on.

Crease Resist Finish: Wash-and-wear or wrinkle-free are some of the synonyms of this finish. This is a chemical resin finish that makes the fiber to quality similar to synthetic fibers.

Singeing: This is a process to remove the fine protruding fibers on the surface of the fabric. Flame singeing is the regular mean to achieve the result. The pre-wet fabric is passed through an array of gas burners at suitable distance to burn out the pills on the surface of fabric.

Peach Finish: Subjecting the fabric (either cotton or its synthetic blends) to emery wheels, makes the surface velvet like. This is a special finish mostly used in garments.

Calendaring: This is a mechanical process to make one or two surface of the fabric smooth and shining. The fabric is passed to thru hot fast moving stainless steel cylinders.

Sanforizing or Pre-shrinking: As the name suggests, this process makes the fabric to reach its optimum shrinkage level, so that it won’t shrink after making it in to a garment. This is also a mechanical finish, acquired by over feeding the fabric between a roller and rubber blanket, in such a way the rubber blanker compresses the weft threads and imparts compressive shrinkage,

Anti-microbial Finish: The basic properties of textile fibers provide suitable environment for the growth of micro organisms. The humid and warm environment in the fiber encourages the growth of the microbes. Infestation by microbes cause cross infection by pathogens and development of odor where the fabric is worn next to skin. In addition to this stains and loss of fiber quality of textile substrates would also take place. With an aim to protect the skin of the user and the textile substrate itself anti microbial finish is applied to textile materials.

Finishes for Synthetic fibers:

Heat Setting: Heat setting of synthetic fabrics eliminates the internal tensions within the fiber generated during manufacture and the new state can be fixed by rapid cooling. This heat setting fixes the fabrics in the relaxed state and thus avoids subsequent shrinkage or creasing of fabric. Presetting of goods make it possible to use higher temperature for setting without considering the sublimation properties of dyes and also has a favorable effect on dyeing behavior and running properties of goods. On the other hand, post setting can be combined with some other operations such as thermosol dyeing or optical brightening of polyester, post setting as a final finish is useful to get a high dimensional stability along with desired handle.

Stiffening and filling Process: A stiffening effect is desirable in certain polyamides and polyester materials for petticoats, collar interlinings, etc., which can be done by reducing the mutual independence of structural element of fabric by polymer deposition on coating as a fine film.

Hydrophilic Finishes: On account of lower moisture and water absorption capacity synthetic fibre materials become uncomfortable in contact with skin. Certain product based on modified (oxy-ethylated) polyamides makes the wearing more pleasant by reducing the cohesion of water so that it spreads over a larger area and thus evaporates more rapidly.

Anti-pilling finish: Pilling is an unpleasant phenomenon associated with spun yarn fabrics especially when they contain synthetics. Synthetic fibers are more readily brought to the surface of fabric due to their smooth surface and circular cross section and due to their higher tensile strength and abrasion resistance; the pills formed take a long time to be abraded by wear. With knit fabric, two more problems occur, viz., "picking" where the abrasion individual fibers work themselves out of yarn loops onto the surface when garment catches a pointed or rough object. These two effects are more predominant in the weave, is more open and yarn is bulkier.

Anti-static finish: Anti-static effective chemicals are largely chemically inert and require Thermosol or heat treatment for fixing on polyester goods. Agents of polyether type are found to be useful but should not effect the dye-equilibrium on fibre otherwise the rubbing fastness is impaired. In general Thermsolable anti-static agents also have a good soil release action which is as permanent as the anti-static effect. Anti-static finishes may also be of polyamide type being curable at moderate temperatures.

Non-slip Finishes: Synthetic warp and weft threads in loosely woven fabrics are particularly prone to slip because of their surface smoothness when the structure of fabric is disturbed and appearance is no loner attractive. To avoid this attempts are made to give the filaments a rougher surface. Silica-gel dispersions or silicic acid colloidal solutions are quite useful and they are used with advantage in combination with latex polymer or acrylates dispersions to get more permanent effect along with simultaneous improvement in resistance to pilling or snagging. These polymer finishes are also capable of imparting a soft and smooth handle to synthetic fabric without imparting water repellency.

Fire Resistant or Flame Retardant Finish: With the increasing use synthetic fibres for carpets and other materials in public places, anti-microbial finishes have assumed importance. A reduction in soiling tendency will along way in keeping textiles free from germs and usual soil repellant as well as soil release finishes are effective in some way. Products which are commonly applied are brominated phenols, quaternary ammonium compounds, organo-silver and tin compounds which can be applied as solutions or dispersions. They can also be incorporated in a polymeric film deposited on the surface to get controlled release. Some reactive systems similar to those for reactive dyes have been recently tried to incorporate anti-microbial structural features.

Enzymatic Finishes: Bio-polishing: This is a process to remove the protruding fibers of a fabric through the action an enzyme. This enzyme selectively acts on the protruding fibers and cease to work after finishing the work by a simple raise in temperature of the treatment bath.