Polyvinyl Alcohol PVA chemical formula is [C2H4O]n, white sheet, wool or powdered solid, odorless. Physical properties of polyvinyl alcohol effects of chemical structure, alcohol sis, degree of polymerization.
Solubility: insoluble in petroleum ether, insoluble in water. Derivatives of cellulose and starch, synthetic resins, and a variety of surfactants are miscible with each other and have good stability.
At room temperature, its aqueous solution pH value is typically at around 5-7, viscosity stability, almost independent of weak acid, weak alkali or organic solvents (esters, ketones, higher alcohols, hydrocarbons) effect, extremely high oil resistance
The use of PVA
1, The vinyl raw material: polyvinyl alcohol after dissolution, spinning, and then of the acetal with Pooh fibre, it is compatible with, such as cotton, wool, viscose blend made from vinyl textiles, widely used in clothing, tarpaulin, curtain line, fishing net rope. In General, the selected average degree of polymerization of 1750 ± 50 PVA17-99 raw materials as well as spinning.
2, Warp slurry
1) dominated by PVA modulation paste, cotton, linen, polyester and vinylon viscose has a good adhesion, smooth after filming, both robust and wear-resistant, promote well-weave of warp and warps in the weaving process friction reduction, bending. Stretch warp caused by steroid such as break, reducing machine breakage rate. Feel neat and weave cloth. Smooth and delicate, oil on canvas is not rough.
2) Polyvinyl alcohol is a water-soluble polymer , mixing , sizing , desizing are very convenient
3) General election low average degree of polymerization of polyvinyl alcohol ( eg PVA15-99 ,16-99 ,17-99) as a slurry is good.
1) cellulose, polyvinyl alcohol 1788 water solution containing material (such as paper, cloth, wood, etc) very strong adhesion, had the advantage of safe non-toxic, can be used for Board-laminated, adhesive for corrugated board and Office with glue. Packing heavy loads such as kraft paper bags for cement, fertilizer, food and other using PVA as Binder.
2) PVA modified urea-formaldehyde resin and phenolic resin can be used as floor panels and Panel adhesives.
3) PVA water solution (by adding suitable fillers, additives) is also widely used in preparation of printing and binding, paper, carton and other paper adhesive needed for the connection.
4) and polyvinyl alcohol under acid catalysis,, butyric aldehyde, Glyoxal and formaldehyde other aldehydes or condensation, can generate more water resistance, adhesion, mechanical strength of polyvinyl-formaldehyde (such as PVAF, PVB) is widely used in safety glass sandwich construction, paints, adhesives, and other fields. PVA polymerization degree increase, Acetal viscosity increases
United States the main consumption areas of adhesives and textile sizing, 76% per cent of total consumption
European consumption aggregate additives, and paper coatings, 68.7% per cent of total consumption
Japan’s major consumer areas are fibers, adhesives, 72% per cent of total consumption
2012 global polyvinyl alcohol consumption of 1.184 million tons, North American consumption of 156,000 tons, per cent of the global total of 13.18%; Western European consumption of 154,000 tonnes, ratio of 13.01%; the Asia-Pacific region is the world’s largest market for polyvinyl alcohol, annual consumption of 822,000 tons, 69.43% per cent of the global total.
In recent years, the steady growth in world consumption of polyvinyl alcohol
1, Textiles: requires less abroad with or without PVA as a paste, modified starch alternative part of the PVA, PVA textile-related needs may be gradually reduced:
2,Adhesive: basic maintenance of stability, as represented by the 24 series will gradually increase with high viscosity, 17 series as the representative of the demand will be reduced:
3,Paper: gradual reduction in global demand, but on domestic products, future varieties with low polymerization degree can earn a certain amount of market share:
4, PVB: increased demand for high quality requirements;
5, Fabric: with its unique performance of high strength, high modulus fiber, as well as alternatives, such as asbestos, their demand will rise sharply;
6, Other: includes biodegradable materials, liquid-crystal display steady growth