Pre and Post Treatment on Fabrics PDF

Pre and Post Treatment on Fabrics Textile Finishes Textile finishing refers to any of a number of different processes that make manufactured textiles ready for consumers. Textile finishing enhances surface appearance and adds other qualities that make products more appealing to buyers. In or...

Pre and Post Treatment on Fabrics Textile Finishes Textile finishing refers to any of a number of different processes that make manufactured textiles ready for consumers. Textile finishing enhances surface appearance and adds other qualities that make products more appealing to buyers. 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. Mechanical Finishing Involving the application of physical principles such as friction, temperature, pressure, tension and many others. Commonly used mechanical finishes include calendaring, compressive shrinkage / Sanforizing, raising, emerizing / sueding / peaching, shearing / cropping. 1- Calendering A process of passing cloth between rollers (or “calendars”), usually under carefully controlled heat and pressure, to produce a variety of surface textures or effects in fabric such as compact, smooth, supple, flat and glazed. 2- Compacting Durable finish imparted on man-made fibers and knitted fabrics by employing heat and pressure to shrink them to produce a crepe and bulky texture. 3- Embossing This particular type of calendering process allows engraving a simple pattern on the fabric. To produce a pattern in relief by passing fabric through a calendar in which a heated metal bowl engraved with the pattern works against a relatively soft bowl, built up of compressed paper or cotton on a metal centre. 4- Sueding Sueding is a mechanical finishing process in which a fabric is abraded on one or both sides to raise or create a fibrous surface. This fibrous surface improves the fabric appearance, gives the fabric a softer, fuller hand, and can mask fabric construction and subdue coloration. 5- Raising or Napping The raising of the fiber on the face of the goods by means of teasels or rollers covered with card clothing (steel wires) that are about one inch in height. Action by either method raises the protruding fibers and causes the finished fabric to provide greater warmth to the wearer makes the cloth more compact, causes the fabric to become softer in hand or smoother in feel; increase durability and covers the minute areas between the interlacing of the warp and the filling. Napped fabrics include blankets, flannel, unfinished worsted, and several types of coatings and some dress goods. 6-Wool Glazing This is done on a special machine, which is used to perform functional finishing on wool fabrics after raising. 7-Shearing Shearing is an important preparatory stage in the processing of cotton cloth. The objective of “Shearing” is to remove fibers and loose threads from the surface of the fabric, thus improving surface finish. 8-Decating Also called Decatizing. A finishing process applied to fabrics to set the material, enhance luster and improve the hand. Fabric wound onto a perforated roller is immersed in hot water or has steam blown through it. 9-Steaming and Heat setting It is done by using high temperatures to stabilize fabrics containing polyester, nylon, or triacetate but not effective on cotton or rayon. 10-Sanforizing or Pre Shrinking Sanforizing is a process whereby the fabric is run through a sanforizer; a machine that has drums filled with hot steam. This process is done to control the shrinkage of the fabric. The fabric is given an optimum dimensional stability by applying mechanic forces and water vapor. Chemical Finishing The finishes applied by means of chemicals of different origins, a fabric can receive properties otherwise impossible to obtain with mechanical means. Commonly used chemical finishes include softening, stiffening / hand-building, easycare / wrinkle-recovery / durable-press, water / oil repellent, soil repellent, soil release, flame retardant, anti-slip, anti-static, anti-pilling, anti-microbial, elastomeric, UV protection, insect resistant / moth protection, bio-polishing, fragrance, moisture management, temperature adaptability, and finishes to improve color fastness of the dyed or printed fabrics. Requirements & Factors Suitability of the finish for all fibers in all forms Desired durability of the finishing effect No loss of desirable fabric properties, e. g. appearance, hand-feel, strength, comfort, abrasion resistance No yellowing of the white finished fabric No change in color of the dyed or printed fabric Safe to use and simple to apply on the fabric Good storage stability and shelf life Good compatibility with other ingredients of the finishing formulation Easy correction in case of faulty finish application Sustainability and no harmful impact on the environment 1-Softening Softening is carried out when the softness characteristics of a certain fabric must be improved, always carefully considering the composition and properties of the substrate. 2-Elastomeric finishes Elastomeric finishes are also referred to as stretch or elastic finishes and are particularly important for knitwear. These finishes are currently achieved only with silicone-based products. The main effect is durable elasticity, because not only must extensibility be enhanced, but recovery from deformation is of crucial importance. After all stresses and disturbing forces have been released, the fabric should return to its original shape. 3-Crease resistant Crease Resistant Finishes are applied to cellulose fibers (cotton, linen and rayon) that wrinkle easily. Permanent Press fabrics have crease resistant finishes that resist wrinkling and also help to maintain creases and pleats throughout wearing and cleaning. 4-Flame retardant treatment Are applied to combustible fabrics used in children’s sleepwear, carpets and curtains and prevent highly flammable textiles from bursting into flame. 5-Anti Pilling Pilling is a phenomenon exhibited by fabrics formed from spun yarns (yarns made from staple fibers). Pills are masses of tangled fibers that appear on fabric surfaces during wear or laundering. Anti pilling finish reduces the forming of pills on fabrics and knitted products made from yarns with synthetic-fiber content, which are inclined to pilling by their considerable strength, flexibility and resistance to impact. 6-Stain and Soil resistant finishes Prevent soil and stains from being attracted to fabrics. Such finishes may be resistant to oil-boure or water-bourne soil and stains or both. Stain and soil resistant finishes can be applied to fabrics used in clothing and furniture. Scotchgard is a stain and soil resistant finish commonly applied to carpet and furniture. 7-Oil and Water proofing Waterproof Finishes -Allows no water to penetrate, but tend to be uncomfortable because they trap moisture next to the body. Recently, fabrics have been developed that are waterproof, yet are also breathable. 8-Anti static finish Reduce static electricity which may accumulate on fibers. The most common type of anti-static finishes is fabric softeners. 9-Antibacterial finish The inherent properties of textile fibers provide room for the growth of micro-organisms. Anti-microbial agents can be applied to the textile substrates by exhaust, pad-dry-cure, coating, spray and foam techniques. The application of the finish is now extended to textiles used for outdoor, healthcare sector, sports and leisure. 10-UV protection finish UV Protection Fabric treated with UV absorbers ensures that the clothes deflect the harmful ultraviolet rays of the sun, reducing a person’s UVR exposure and protecting the skin from potential damage. The extent of skin protection required by different types of human skin depends on UV radiation intensity and distribution with reference to geographical location, time of day, and season. This protection is expressed as SPF (Sun Protection Factor), higher the SPF value better is the protection against UV radiation. 11-Color Fastness improving finish Color fastness is the resistance of a material to change in any of its color characteristics, to the transfer of its colorants to adjacent materials or both. Fading means that the color changes and lightens. Bleeding is the transfer of color to a secondary, accompanying fiber material. This is often expressed as soiling or staining meaning that the accompanying material gets soiled or stained. Fabric Printing What is Textile Printing? Textile printing is the process of applying colour to fabric in definite patterns or designs. In properly printed fabrics the colour is bonded with the fibre, so as to resist washing and friction. Textile printing is related to dyeing but in dyeing properly the whole fabric is uniformly covered with one colour, whereas in printing one or more colours are applied to it in certain parts only, and in sharply defined patterns. Digital Textile Printing Digital textile printing is often referred to as direct-to-garment printing, DTG printing, or digital garment printing. It is a process of printing on textiles and garments using specialized or modified inkjet technology. Inkjet printing on fabric is also possible with an inkjet printer by using fabric sheets with a removable paper backing. Heat Transfer Heat transfer, also known as thermal printing is a method of printing that allows you to print a design onto a piece of clothing or an object. Heat transfer printing uses the process of heat to transfer an image created in wax to an object or garment. This printing method is compatible with pre-painted images on a wax sheet or can be used to create an image by layering wax dye onto an object. Sublimation Printing Sublimation printing is a digital printing process that uses heat, pressure, and time to transfer dye onto different materials. Here’s the full process: You print a design onto special transfer paper using sublimation inks Then, you place the printed paper onto a product and heat it with a heat press The heat, pressure, and time turns the inks into a gas, and the material absorbs them As a result, you get a permanent, vibrant print that won’t fade or crack over time Rotary Printing Rotary printing is a traditional textile printing method. This process differs greatly from modern digital processes. Rotary printing has unique capabilities and allows for process control that digital printing doesn’t. Rotary printing is a continuous method of printing in which a perforated cylindrical screen applies a colorant made from either pigment or dye. The colorant is forced from the interior of the cylindrical screen and onto the fabric. Screen Printing Screen Printing is a process where ink is forced through a mesh screen onto a surface. Making certain areas of the screen impervious to printing ink creates a stencil, which blocks the printing ink from passing through the screen. The ink that passes through forms the printed image. A printing screen consists of a fine mesh fabric that is tightly stretched and attached to a metal or wooden frame. Block Printing Block printing is the process of printing patterns by means of engraved wooden blocks. It is the earliest, simplest and slowest of all methods of textile printing. Block printing by hand is a slow process. It is, however, capable of yielding highly artistic results, some of which are unobtainable by any other method.