Polyvinyl alcohol fiber
Wikipedia business card Synthetic fiber made by spinning polyvinyl alcohol as raw material. Introduction Synthetic fiber made by spinning polyvinyl alcohol as raw material. Polyvinyl formal fiber obtained by treating this fiber with formaldehyde is known as vinylon in China, and vinylon as internationally. Fibers made by spinning low molecular weight polyvinyl alcohol as a raw material are water-soluble and are called water-soluble polyvinyl alcohol fibers. General polyvinyl alcohol fibers do not have the necessary hot water resistance and have little practical application value. Polyvinyl formal fiber is soft, warm, and other characteristics, especially the moisture absorption rate (up to 5%) in the synthetic fiber variety is relatively high, it is known as synthetic cotton; but its poor heat resistance, softening point only 120 °C. History In the early 1930s, Wacker Chemie AG first produced polyvinyl alcohol fibers. In 1939, Japanese Sakurada Ichiro, Yazawa Eunyo, and North Korea Lee Seung Gi treated this fiber with formaldehyde to obtain heat-resistant polyvinyl formal fiber. In 1950, it was made by Japan Kurashiki Rayon Co., Ltd. (now Kuraray The company) built industrial production facilities. In 1984, the world production of polyvinyl alcohol fibers was 94 kt. In the early 60s, water-soluble polyvinyl alcohol fibers produced by Japan's Vinylon and Kuraray were placed on the market. production method The polyvinyl alcohol fiber used as the raw material has an average molecular weight of 60,000 to 150,000, a thermal decomposition temperature of 200 to 220°C, and a melting point of 225 to 230°C. Polyvinyl alcohol fibers can be obtained by wet spinning and dry spinning. Polyvinyl formal fibers can be obtained by acetalizing polyvinyl alcohol fibers after heat treatment. In the acetalization process, the tow is washed with water to remove Glauber's salt (sodium sulfate), and then passed through a hydroformylation solution (formed by formaldehyde agent, diluent water, catalyst sulfuric acid, swelling agent sodium sulfate) and then washed with water. the process of. The tow can also be cut into short fibers, conveyed to a post-processing machine by air flow, and acetalized on a stainless steel mesh. In order to improve fiber properties, a solution of boric acid in a solution of boric acid in polyvinyl alcohol (16% concentration) is subjected to wet spinning. The resulting primary fiber is coagulated in an alkaline coagulation bath, neutralized, washed with water, and multistage high-strength stretched. With heat treatment, filaments with a strength of 106 to 115 cN/dtex can be obtained. This product is called boron-containing wet filaments. use Polyvinyl formal fibers can be used in the industrial field for the production of canvases, tarpaulins, filter cloths, conveyor belts, packaging materials, work clothes, fishing nets and offshore work cables. High-strength, high-modulus filaments can be used as lining materials for conveyor belts, lining materials for various hoses, tapes, and shoes, as well as bicycle tire cords. Because this fiber is resistant to the alkalinity of cement and has good adhesion and affinity with cement, it can replace asbestos as a reinforcing material for cement products. It can be blended with cotton to make a variety of clothing and interior products, as well as knitwear. However, the heat resistance is poor and the resulting fabric is not stiff and cannot be washed in hot water. In addition, it also has use value in non-woven fabrics, papermaking and other aspects. Dissolving Polyvinyl alcohol fibers can be blended with other fibers, and then dissolved after textile processing to obtain high-grade textiles for spun yarns, and also to obtain untwisted or weft-free blankets. It can also be used as a binder in papermaking to increase the strength and toughness of paper. In addition, special-purpose work clothes, surgical sutures, etc. can also be made. Modified polyvinyl alcohol fiber The important modified species is vinyl chloride-polyvinyl alcohol graft copolymer fiber, which is known as Vylon in China. It uses a low polymerization degree polyvinyl alcohol solution as a dispersion medium, and under the action of a catalyst, vinyl chloride and a polyvinyl alcohol are graft copolymerized; from the obtained copolymer emulsion, spinning is performed by an emulsion spinning method (see chemical fiber spinning). Fibers; Finished fiber products are obtained by similar post-treatment processes with polyvinyl formal fibers. It combines the advantages of polyvinyl chloride fibers and polyvinyl formal fibers. Modal Scarf,Modal Fabric Scarf,Modal Wool Scarf,Cashmere Modal Scarf Inner Mongolia Jinshitaihua Cashmere Accessories Co.,Ltd , https://www.thcashmer.com