Abstract: Disclosed is an anti-fouling agent which is superior in viscosity stability, water resistance of its film and ability of preventing a scale from depositing on the inner wall of a polymerization reactor and which can prevent the contamination of foreign substances into a polymeric product caused by exfoliation of a scale depositing on the inner wall of a polymerization reactor and exfoliation of the anti-fouling agent itself, the anti-fouling agent comprising an aqueous solution containing a polyvinyl alcohol that is obtained through saponification of a polyvinyl ester that contains monomer units having a specific silyl group and that satisfies the following formulae (I) and (II): 370<P×S<9000??(I) wherein P indicates the viscosity-average degree of polymerization of the polyvinyl alcohol, and S indicates the content (mole %) of the monomer units having a silyl group of formula (1) in the polyvinyl alcohol; 0.

Abstract: The present invention provides polyvinyl alcohol based (PVA) whose solubility in water varies with a small temperature change to a sufficiently great degree. In manufacturing a polyvinyl alcohol based polymer by: progressing a transesterification reaction of a polyvinyl ester based polymer with alcohol in a liquid reaction mixture including the polyvinyl ester based polymer, the alcohol, and a basic compound; precipitating the polyvinyl ester based polymer, at least a part of which has been transesterified with the alcohol, out of the liquid reaction mixture; and further progressing the transesterification reaction in the liquid reaction mixture including the polyvinyl ester based polymer that has precipitated, the liquid reaction mixture has a temperature of 75° C. to 150° C. when the polyvinyl ester based polymer, at least a part of which has been transesterified, starts precipitating.

Abstract: The invention provides a novel polyvinyl acetal having N-vinylamide monomer units in the molecule, and provides a binder with the novel polymer for ink or paint and for ceramic forming. Compared with conventional polyvinyl acetals, the novel polymer lowers the solution viscosity and increases the solid content (pigment content) of ink or paint in which the polymer serves as a binder. The binder with the novel polymer for ceramic molding enables production of thin and homogeneous ceramic green sheets of high strength.

Abstract: The invention provides a polyvinyl acetal having a degree of acetalization of from 45 to 80 mol %, which is obtained through acetalization of a polyvinyl alcohol having a degree of polymerization of from 30 to 1000 and a degree of hydrolysis of from 80.0 to 99.99 mol % and having a specific amount of an ionic group bonded to the terminal thereof via a sulfido bond. The polyvinyl acetal of the invention is useful for binders for ceramic forming and for binders for ink or paint.

Abstract: A ceramic-molding binder includes a vinyl alcohol polymer having an ethylene unit content of 2 to 19 mole %, a polymerization degree of 200 to 2,000, a degree of saponification of 80 to 99.99 mole %, and a carboxylic acid and lactone ring content of 0.02 to 0.4 mole %. The use of the ceramic-molding binder provides green moldings with better formability and handling properties during the formation of smaller green moldings of more complex shape, and also provides ceramic products of good quality, higher yields, and fewer ceramic cracks when obtained by sintering such green moldings.

Abstract: A polyvinyl alcohol obtained by hydrolysis of a polyvinyl ester that contains silyl group functionalized monomer units.

Abstract: The invention provides a polyvinyl acetal having a degree of acetalization of from 45 to 80 mol %, which is obtained through acetalization of a polyvinyl alcohol that contains from 1 to 15 mol % of &agr;-olefin units and has a 1,2-glycol bond content of from 1 to 3 mol %, a degree of polymerization of from 100 to 2000 and a degree of hydrolysis of from 80.0 to 99.99 mol %. The polyvinyl acetal has good waterproofness and good compatibility with plasticizer. Having the advantages, it is favorable for interlayer films for laminated glass, binders for ceramic forming, binders for ink or paint, and coating liquids for thermally-developable photographic materials.

Abstract: A polyvinyl alcohol having hydrolyzed silyl group functionalized monomer units.

Abstract: Vinyl alcohol polymers having an ethylene unit content of 2 to 19 mole %, a polymerization degree of 200 to 2,000, a degree of saponification of 80 to 99.99 mole % and a total content of carboxyl group and lactone rings of 0.02 to 0.4 mole % are excellent in thermal stability, water resistance, gas-barrier properties, water vapor-barrier property, stability of aqueous solution kept at low temperatures and biodegradability.

Abstract: A vinyl alcohol polymer with a side chain being a hydroxyalkyl group having 2 to 20 carbon atoms is disclosed. Conventional water-soluble vinyl alcohol polymers gives, where they have a high interfacial activity, an aqueous solution with much-foaming and hence a problem when used for commercial purposes. On the other hand, the vinyl alcohol polymer of the present invention gives, where it is water-soluble, an aqueous solution with less-foaming in spite of its high interfacial activity, and hence an excellent industrial applicability. The vinyl alcohol polymer of the present invention is useful as thermoplastic resin and dispersion stabilizer. In addition, the vinyl alcohol polymer of the present invention is usable for various purposes, e.g.

Abstract: Disclosed herein is a polyvinyl alcohol shaped article which comprises a polyvinyl alcohol (A) and rubber particles (B), said rubber particles (B) comprising a rubber component having a glass transition temperature of 5.degree. C. or less and an average particle diameter of 5 .mu.m or less and a polyvinyl alcohol (C) being bonded to the surface of said rubber component, with the weight ratio of said rubber component on the basis of the total weight of said polyvinyl alcohols being in the range of 0.03 to 2. The polyvinyl alcohol shaped article of the present invention has a high impact strength at low temperatures and in low humidity, and also has a high strength and Young's modulus in high humidity, and has an excellent appearance.