Polyurethane
used in the textile industry
According to data from the Polyurethane Division of the American Plastics Industry Association, the usage of polyurethane in the U.S. anti-woven and leather industries ranks eighth in the entire industry, second only to construction, transportation, furniture, carpets, instruments, and bedding. The usage of polyurethane in other industries is showing a growing trend. The main uses of polyurethane in the textile industry are as follows:
1 Elastic fiber and its fabric
As early as 1954, DuPont of the United States had produced a polyurethane fiber called Spondex (referred to as spandex). Because it has high elasticity similar to rubber, it is also called elastic fiber. The woven, knitted or non-woven fabrics made from it have an elasticity of about 40% and a high elongation of about 150%, so they can be used to produce various bodysuits, underwear, swimwear and other sportswear, ballet and other theater costumes, Stretch stockings, shoes and hats and other human body articles and bandages, clothing and other products. In addition, it is currently being widely used with different fibers such as cotton, polyester, nylon, and silk to manufacture composite textile products, and various fabrics for clothing, shoes and hats are produced on a large scale by methods such as knitting, warp and weft knitting, and shuttle weaving. and elastic bands. Composite textiles using the above-mentioned spandex silk and other fibers have been produced at home and abroad, such as new silk/spandex-coated silk products, including silk stretch silk, silk stretch pantyhose, etc. The former can be used as new clothing materials, new fabrics for shoes and hats, or other parts or decorations with stretch properties; spandex warp elastic corduroy is a new fabric with elasticity, rich fluff, soft color, etc., and it is also a shoe with good warmth retention properties. Hat material; spandex non-woven fabric (non-woven or woven-free fabric) has the advantages of simple production, low cost, softness, waterproof, moisture permeability, etc. It can be widely used in clothing, shoes and hats, medical, industrial and mining and other industries to make Underwear, apparel, linings, bottom pads, masks, bandages, hoods, shoe covers, industrial filter cloth and other products.
2. Textile auxiliaries
Aqueous dispersions or solutions of polyurethane have been widely used as textile printing and dyeing auxiliaries and finishing agents in the textile and tanning industries.
1 Dyeing and printing auxiliaries
1.1 Dyeing auxiliaries
For example, cationic water-dispersed polyurethane can be used as a pre-dyeing treatment agent to improve the dyeability of fabrics or non-woven fabrics. In addition, some water-dispersed polyurethanes can react with a variety of fibers and dyes, thereby significantly improving the fastness of dyed goods.
1.2 Printing adhesive
For example, the domestically developed water-dispersed heat-reactive polyurethane PUT-02, which uses sodium ammonium sulfite as the end-capping agent, can be used in large-area paint printing to improve the adhesion between paint and fabrics and the wear resistance of printed fabrics. .
1.3 Special printing adhesive
Water-dispersed polyurethane can be used as a special printing adhesive, mainly used in transparent printing and matte printing. For the former, water-dispersed polyurethane with excellent permeability and non-yellowing should be used, such as Dainippon Ink Company’s E A 1005 variety, the thermal reaction product series Elastron of Japan Daiichi Pharmaceutical Industry Co., Ltd. Although they are generally used in polyester thin fabrics, they can also be used in cotton and woolen fabrics, such as transparent printing prescriptions on cotton.
2 Finishing agent
Polyurethane can be used as a finishing agent for natural fiber fabrics and synthetic fiber fabrics. It can adjust and improve the fabric’s fullness, anti-wrinkle and anti-pilling properties.
2.1 Softness and anti-wrinkle finishing agent
Water-dispersed polyurethane does not contain formaldehyde and has good film-forming and flexible properties, so it can completely or partially replace amino resin as an anti-wrinkle finishing agent or softening additive for fabrics. If cotton fabrics or polyester-cotton blended fabrics are immersed in a diluent of 2-5% concentration water-dispersed polyurethane and cured at 126°C, the softness and wrinkle resistance of the fabrics can be improved. In addition, two different types of water-based dispersion polyurethane are used.One of the elements of final performance is the film-forming properties of the dispersed particles. That is to say, it is required that a continuous film must be formed on the surface of the base fabric under dry conditions at room temperature or slightly elevated temperature. Otherwise, the gloss of the film layer will be low and the overall performance will be poor. For this, if ketones such as N-methylpyrrolidone are added, the film will be Boiling point solvents or plasticizers can improve film-forming properties.
In addition, in water-based polyurethane, thickeners, defoamers or foam generators, antifungal agents, light stabilizers, antioxidants, fillers, feel improvers, matting agents, and flame retardants should be added as appropriate. , cross-linking agent, catalyst or colorant, etc. The tape coated with synthetic leather coating agent and natural leather finishing agent is the coated fabric with the thickest coating layer. It can be mainly used as waterproof and dustproof materials and special human wear items, such as raincoats, diving suits, etc. Wading pants, fishing pants, rain hats, rain boots, swimming caps, swimming fins, work caps, protective clothing, fire suits, rafts, waterproof bags, water storage containers, small sheds, aircraft or vehicle covers, etc. In addition, polyurethane adhesive or linters can also be used in electrostatic flocking and flocking printing of rubber or plastic sheets to produce highly decorative tapestries or carpets. For example, domestic Changzhou Chemical Factory has developed a new solvent-free two-component polyurethane adhesive for electrostatic flocking. Component A is a prepolymer with isocyanate terminals, while component B is a prepolymer with hydroxyl terminals. According to the ratio After full stirring, even coating on the substrate, and then electrostatic flocking and adhesive synthesis, the heating-reactive or cross-linked water-based polyurethane can be prepared, which is more suitable for flocking dry and wet fastening. The above-mentioned products with a temperature of more than 10,000 times
Application of 4 in textile machinery and equipment
Polyurethane elastomers are also widely used in textile machinery and equipment. For example, textile rubber rollers can be used for combing, combing, and roughening
