Polyurethane used in the textile industry

Polyurethane used in the textile industry

According to the information from the Polyurethane Division of the American Society of Plastics Industry, the amount of polyurethane used in the U.S. anti-weaving and tanning industries is the eighth largest in the industry, i.e., second only to the use in the construction, transportation, furniture, carpet, instrumentation, bedding and other industries, showing a growing trend, and the main uses of polyurethane in the textile industry are as follows.

 

1 Elastic fiber and its fabric

As early as l954, the U.S. DuPont Company has produced a polyurethane fiber called Spondex (referred to as spandex), which is also called elastic fiber because it has a high elasticity similar to rubber. The woven, knitted or non-woven fabric made of it has an elasticity of about 40 and a high elongation of about 50, so it can be used to produce a variety of tight-fitting pants, underwear, sportswear such as swimwear, ballet and other theatrical wear, elastic stockings, shoes and hats and other articles for human use and bandages, clothing and other parts. In addition, at present, it is widely used with cotton, polyester, nylon, silk and other different fibers and used to manufacture composite textile products, and knitting, warp and weft knitting and shuttle weaving and other methods of large-scale production of a variety of clothing and shoes and hats with fabrics and elastic bands. At home and abroad, we have produced composite textiles using the above-mentioned spandex and other fibers, such as silk/spandex covered silk products, including silk stretch silk, silk stretch pantyhose, etc. The former can be used as new clothing, silk stretch pantyhose. The former can be used as new clothing materials, new fabrics for shoes and hats or other parts with stretch performance or decorative parts; spandex by the elastic light velvet, both elastic, rich pile, soft color and other characteristics of the new fabric, but also has good warmth performance of shoes and hats with materials; spandex non-woven fabric (non-woven or non-woven fabric), with easy production, low cost, soft, waterproof, moisture permeable and other excellent features, can be widely used in clothing, shoes and hats, medical, industrial and mining industries to Medical, industrial and mining industries to make underwear, clothing, lining, bottom cushion, mask, bandage, hood, shoe cover, industrial filter cloth and other products.

2 Second, textile auxiliaries

Polyurethane aqueous dispersion or solution has been widely used as textile printing and dyeing auxiliaries, finishing agents in the textile and tanning industry.

1 dyeing and printing auxiliaries

1.1 Dyeing auxiliaries

Such as cationic water-dispersible polyurethane can be used as a pre-dyeing agent, which can improve the dyeability of fabrics or non-woven. In addition, some water-dispersible polyurethane can react with a variety of fibers and dyestuffs, which can significantly improve the fastness of the dyed material.

1.2 Printing binder

For example, the water dissipation reactive polyurethane PUT-02 developed domestically with sodium sulfite as a capping agent can be used in large-area paint printing, which can improve the adhesion between paint and fabric and the abrasion resistance of printed fabric.

1.3 Special printing binders

Water dispersible polyurethane can be used as special printing adhesives, mainly for transparent printing and matte printing, for the former should be used with excellent permeability and non-yellowing water-dispersible polyurethane, such as Dai Nippon Ink Company’s E a 1005 varieties, Japan’s first pharmaceutical industry company’s heat reaction products Elastron, etc.. Although they are generally used for polyester thin fabrics, but can also be used in cotton and wool fabrics such as cotton transparent printing prescription.

2 Finishing agent

Polyurethane can be used as a finishing agent for natural fiber fabrics and synthetic fabrics, can adjust and improve the feel of the fabric fullness, anti-wrinkle and anti-pilling and other properties.

2.1 Soft and anti-wrinkle finishing agent

Water-dispersible polyurethane does not contain formaldehyde, and has good film and flexibility, so it can completely or partially replace the amino resin as an anti-wrinkle finishing agent or soft additive. Such as cotton fabrics or polyester-cotton blended fabrics impregnated with 2-5% concentration of water-dispersible polyurethane dilution, and cured at 126 ℃, can improve the softness and wrinkle resistance of the above fabrics. In addition, using a mixture of two different types of water-dispersible polyurethane impregnation of cotton blended fabrics, it can make it simultaneously obtain softness, wrinkle resistance and water repellency.

2.2 Waterproof and breathable finishing agent

Polyurethane can be used as the waterproof and breathable coating of the fabric, so that the fabric has the function of waterproof and breathable. If the dimethylformamide solution of polyurethane can be coated on the fabric and then immersed in water, the mutual replacement of dimethylformamide and water can form a porous film on the fabric that can be waterproof and breathable, and the above function can be obtained, but there is a tendency to use water-dispersible polyurethane. It can not only get the above functions, and non-toxic, low cost and high yield advantages.

2.3 Fabric imitation hemp finishing agent

Compared with the general imitation hemp finishing, moisture dissipation reactive polyurethane imitation hemp finishing agent is one of the most important features of strong resistance to washing, because of its low molecular weight, strong permeability to the fabric, and can react with the fiber and cross-link themselves into a film Especially with natural polysaccharides as raw materials, the synthesis of water-dispersible polyurethane, not only can improve the finishing fabric water absorption, but also does not cause fading of dyes, so it is a class of advanced imitation hemp Finishing agent.

2.4 Antistatic and hydrophilic finishing agent

Such as the above Ehstron series of W-N. Can be used as a durable antistatic and hydrophilic finishing agent for fabrics, by W-11 finishing of polyester Pallis fabric, after 10 washes can not maintain high antistatic and hydrophilic performance.

2.5 Wool anti-wrinkle finishing agent

Such as by the German company Bayer produced a reactive water-dispersible polyurethane, if mixed with polyethyleneimine, and in the role of non-ionic agglutination thorn, wool and its blends can be made to get a higher anti-shrink effect. In addition, Elastron BAP water-dispersible polyurethane can be used not only in the shrinkage prevention processing of wool, but also in the anti-felting and anti-pilling finishing of wool fabrics.

2.6 Non-iron finishing agent

If the hydroxyethyl lignin sulfonate (HELS) and aromatic isocyanate phase reaction, lignin polyurethane can be produced, with which the cotton fabric treatment, can improve the fabric’s non-iron performance.

2.7 Water- and oil-repellent finishing agent

If the oxygenated polyurethane emulsion and cyanoacrylate polymer emulsion mixed, as a finishing agent to treat the fabric, can make the fabric with water and oil repellent effect.

3 Nonwoven Binders

Polyurethane alone or in combination with rubber or resin emulsions such as natural, butyl, nitrile, acrylate, polyvinyl acetate or polyethylene can be used as a binder in the production of nonwoven fabrics. As fiber materials can be cotton, hemp, wool, viscose, synthetic, glass, asbestos and other fibers, respectively, can be manufactured clothing lining, fabric, shoe and hat lining, napkins, curtains, artificial leather base cloth, plastic or rubber products, reinforcing materials, filter cloth and other industrial materials.

3 coated fabrics and other products

Coated fabrics are uniformly coated with polyurethane continuous film on the surface of the fabric, so that the fabric changes the appearance, style, improve performance, increase the function of the secondary processing products, which is a newly developed processing technology in the textile finishing. At present, the world’s coated textiles have accounted for 20% of the total output of textiles, and 30% of the total output value in terms of value.

The fibers used in coated fabrics can be cotton, hemp, silk, wool synthetic fibers, viscose fibers and other single pure fibers, and also can be blends of the above materials. In addition, the coating process can be used dry, wet, wet and dry method, transfer, iterative and foam lamination and other methods. The coating process generally does not require washing, so it can save water and reduce the amount of sewage generation, in addition, the low-grade base cloth can be used to produce high-grade fabrics, significantly increasing the added value of the product. Since fabric coating has many advantages mentioned above, it is a promising processing technology in the world textile industry today.

Fabric coating agent has largely undergone the process of transformation from tung oil, gum, plant sap and other natural raw materials to rubber (rubber SL), plastics and other synthetic polymers. At present, polyvinyl chloride, polyurethane, polyacrylate, polysiloxane, natural rubber, synthetic rubber (such as styrene butadiene rubber, neoprene, modified neoprene, nitrile rubber, chlorosulfonated polyethylene, etc.), thermoplastic elastomers represented by styrene, polyvinyl alcohol, polyamides, ethylene, etc., are often used. Polyvinyl alcohol, polyamide, ethylene vinyl acetate and polytetrafluoroethylene thermoplastic resins. But the amount of polyvinyl chloride, polyurethane and polyacrylate is large.

3.1 Thin coating

Fabric thin coating fabric refers to the nylon spinning, polyester taffeta and other thin fabrics directly coated with coating agent on the fabric products with a thin coating generally has a light weight, soft, high strength, impervious to water and other excellent features. If the coating agent is made of polynitrite, it can improve the softness, waterproof and moisture permeability, wear-resistance and other characteristics of the products. Such as domestic Yantai Wanhua Synthetic Leather Group Technology Company’s direct coating of fabric with high water pressure polyurethane coating agent, using polyethylene-ethylene-propylene glycol polyglycol (PEPA) and polypropylene glycol for oligomer glycol, diphenylmethane diisocyanate (MDI), ethylene glycol for chain extender, phenyl salicylate for light stabilizer. rain line speed for one or two scraping, and then 120 ℃ and 160 ℃ two drying, that can be made of high strength, good elasticity, soft feel, high water pressure and non-stick thin coated fabric, suitable for making raincoat, windbreaker, sportswear, cold clothing, travel clothing and down clothing and other clothing.

In addition, in addition to the above solution-type coating agent, the domestic Yantai Chemical Research Institute has developed a series of water-emulsion coating agent: such as water-emulsion polyurethane coating agent for viscose fiber fabrics, water-emulsion polyurethane coating agent for nylon spinning and polyester spinning, water-emulsion poly-nitrogen ester coating agent for polyester canvas waterproof, silver and white water-emulsion poly-nitrogen ester coating agent, etc. The above water-emulsion polyurethane coating agent is a water-emulsion polyurethane coating agent containing carboxyl octane.