Abstract: Release paper base paper includes a substrate; and a coating agent containing a modified polyvinyl alcohol (A) and sodium acetate, the substrate coated with the coating agent, wherein the modified polyvinyl alcohol (A) has 0.005 mol % or more and less than 10 mol % of double bonds derived from unsaturated carboxylic acid or a derivative thereof (B) in side chains, has 1.4 mol % or more and 2.0 mol % or less of 1,2-glycol bond, units, and is water soluble, and a content of the sodium acetate relative to the modified polyvinyl alcohol (A) is 0.01 mass % or more and 10 mass % or less. The release paper base paper of the present invention is excellent in sealing properties for silicone. Use of the release paper base paper allows acceleration of curing of silicone in a release layer and improvement in adhesion between the substrate and the release layer.

Abstract: There is provided a composition (C) comprising a modified PVA (A) and a compound (B), wherein the modified PVA (A) contains 0.01 mol % or more and less than 2 mol % of double bonds derived from an unsaturated carboxylic acid or a derivative thereof in side chains; the compound (B) is a compound having a conjugated double bond and two or more hydroxy groups bonded to the conjugated double bond, or a salt or oxide thereof; and a content of the compound (B) in the composition (C) is 0.001 parts by mass or more and less than 5 parts by mass based on 100 parts by mass of the modified PVA (A). The composition (C) has excellent hue, contains less insolubles in water, and has excellent water solubility.

Abstract: A method for producing a vinyl polymer by suspension-polymerizing a vinyl compound in the presence of a dispersion stabilizer, wherein the dispersion stabilizer contains a polyvinyl alcohol and a composition containing a modified polyvinyl alcohol and a compound; the modified polyvinyl alcohol contains double bonds derived from an unsaturated carboxylic acid or a derivative thereof in side chains; the compound is a compound having two or more hydroxy groups bonded to a conjugated double bond; the modified polyvinyl alcohol has a saponification degree and a viscosity-average polymerization degree different from those of the polyvinyl alcohol; a content of the compound in the composition is 0.001 parts by mass or more and less than 5 parts by mass based on 100 parts by mass of the modified polyvinyl alcohol; and a mass ratio of the composition to the polyvinyl alcohol is 50/50 to 90/10.

Abstract: A modified vinyl alcohol polymer powder having a structural unit derived from a derivative of an ethylenically unsaturated dicarboxylic acid, and containing a reduced amount of methanol, and a trace amount of a component that does not dissolve in water. The present invention relates to a modified vinyl alcohol polymer powder containing a structural unit derived from a derivative (A) of an ethylenically unsaturated dicarboxylic acid in a content (X) of 0.05 mol % or more and 10 mol % or less, and having a degree of saponification of 80.0 mol % or more and 99.9 mol % or less, the modified vinyl alcohol polymer powder has a methanol content of 0.01 weight % or more and less than 3.0 weight %, the modified vinyl alcohol polymer powder contains 0.1 ppm or more and less than 2,000 ppm of a component that is insoluble in a 90° C., 5 weight % aqueous solution.

Abstract: The present invention provides an aquatic organism repellent paint composition having good dispersion stability and capable of maintaining the repellent effect on aquatic organisms over a long time. The present invention relates to an aquatic organism repellent paint composition containing: a vinyl alcohol polymer (A) having a degree of saponification of more than 65 mol % and less than 88 mol %; an inorganic oxide (B); and a solvent (C).

Abstract: A composite gel in one aspect of the present disclosure comprises a substance prepared by gelling a raw material composition that comprises, as main components, a hydroxyl group-containing organic polymer compound and one of a hydroxyl group-containing inorganic compound and an inorganic oxide. A method for manufacturing the composite gel in one aspect of the present disclosure comprises a first process of gelling a raw material composition that comprises, as main components, a hydroxyl group-containing organic polymer compound and at least one of a hydroxyl group-containing inorganic compound or an inorganic oxide; and a second process of drying and subsequently pulverizing a resulting product in the first process to thereby obtain a composite gel fine powder.

Abstract: A dispersion stabilizer for suspension polymerization is provided that includes a vinyl alcohol-based polymer (A), wherein a 0.1 mass % concentration aqueous solution of the polymer (A) has an absorbance (a1) of less than 0.25 at a wavelength of 280 nm, the aqueous solution has an absorbance (a2) of less than 0.030 at a wavelength of 320 nm, the polymer (A) has a degree of saponification of not less than 68 mol % and not more than 98 mol %, the polymer (A) has a viscosity-average degree of polymerization of more than 1500 and less than 4500, and the polymer (A) in powder form has a YI value of not less than 5. The dispersion stabilizer is capable of producing a vinyl-based resin that is excellent in polymerization stability, has a small particle size, and has an improved bulk density.

Abstract: A dispersion stabilizer for suspension polymerization is provided that includes a vinyl alcohol-based polymer (A), wherein a 0.1 mass % concentration aqueous solution of the polymer (A) has an absorbance (a1) of less than 0.25 at a wavelength of 280 nm, the aqueous solution has an absorbance (a2) of less than 0.030 at a wavelength of 320 nm, the polymer (A) has a degree of saponification of not less than 68 mol % and not more than 98 mol %, the polymer (A) has a viscosity-average degree of polymerization of more than 1500 and less than 4500, and the polymer (A) in powder form has a YI value of not less than 5. The dispersion stabilizer is capable of producing a vinyl-based resin that is excellent in polymerization stability, has a small particle size, and has an improved bulk density.

Abstract: A dispersion stabilizer for suspension polymerization of vinyl compounds comprising a vinyl alcohol polymer (A) which has a saponification degree of 30 mol % or more and less than 60 mol % and a viscosity-average polymerization degree (P) of more than 200 and less than 600, and has a terminal alkyl group having 6 to 18 carbon atoms, and in which a content of monomer units having an oxyalkylene group is 0.3 mol % or less and the relationship between the viscosity-average polymerization degree (P) and a modification rate (S) (mol %) of the alkyl group satisfies Formula (1). Thus, there can be provided a dispersion stabilizer for suspension polymerization with which, during suspension polymerization of vinyl compounds including vinyl chloride, even when it is used in a small amount, the absorbency of a plasticizer is high, resulting in easy processing and formation of coarse particles is little and the remaining monomer components can be easily removed. 50?S×P/1.

Abstract: A dispersion stabilizer in the present invention contains an aqueous emulsion (a) obtained by dispersing a polymer (A) having an ethylenically unsaturated monomer unit in an aqueous medium, a PVA (B) having a degree of saponification of 65 mol % or more and less than 82 mol % and a viscosity-average degree of polymerization of 250 or more and less than 1500, and a PVA (C) having a degree of saponification of 82 mol % or more and less than 98 mol % and a viscosity-average degree of polymerization of 1500 or more and less than 4000. The dispersion stabilizer contains: 7 to 51 mass % of the polymer (A); 40 to 84 mass % of the PVA (B); and 9 to 53 mass % of the PVA (C), with respect to a total amount of the polymer (A), the PVA (B), and the PVA (C). A vinyl resin satisfying required performance can be obtained using the dispersion stabilizer.

Abstract: The present invention provides a highly water-soluble and easy-to-handle dispersion stabilizer for suspension polymerization that meets the following requirements: even if the amount of the dispersion stabilizer for suspension polymerization used for suspension polymerization of a vinyl compound is small, the resulting vinyl resin has high plasticizer absorptivity and is easy to work with; it is easy to remove residual monomer components from the resulting vinyl resin; and the resulting vinyl resin contains fewer coarse particles. The present invention relates to a dispersion stabilizer for suspension polymerization of a vinyl compound. This dispersion stabilizer contains a vinyl alcohol polymer (A) having a degree of saponification of 20 mol % or more and less than 65 mol %, a viscosity average degree of polymerization (P) of 100 or more and less than 600, an aliphatic hydrocarbon group having 6 to 18 carbon atoms at its terminal, and an anionic group in its side chain.

Abstract: The present invention provides an easy-to-handle dispersion stabilizer for suspension polymerization that meets the following requirements: even if the amount of the dispersion stabilizer for suspension polymerization used for suspension polymerization of a vinyl compound is small, the resulting vinyl resin has high plasticizer absorptivity and is easy to work with; it is easy to remove residual monomer components from the resulting vinyl resin; and the resulting vinyl resin contains fewer coarse particles. The present invention relates to a dispersion stabilizer for suspension polymerization in the form of an aqueous liquid. This dispersion stabilizer contains, at a concentration of 20 mass % or more and 50 mass % or less, a PVA having a degree of saponification of 35 mol % or more and 65 mol % or less, a viscosity average degree of polymerization of 100 or more and 480 or less, a terminal aliphatic hydrocarbon group having 6 to 12 carbon atoms, and a block character of residual ester groups of 0.5 or more.

Abstract: A dispersion stabilizer in the present invention contains an aqueous emulsion (a) obtained by dispersing a polymer (A) having an ethylenically unsaturated monomer unit in an aqueous medium, a PVA (B) having a degree of saponification of 65 mol % or more and less than 82 mol % and a viscosity-average degree of polymerization of 250 or more and less than 1500, and a PVA (C) having a degree of saponification of 82 mol % or more and less than 98 mol % and a viscosity-average degree of polymerization of 1500 or more and less than 4000. The dispersion stabilizer contains: 7 to 51 mass % of the polymer (A); 40 to 84 mass % of the PVA (B); and 9 to 53 mass % of the PVA (C), with respect to a total amount of the polymer (A), the PVA (B), and the PVA (C). A vinyl resin satisfying required performance can be obtained using the dispersion stabilizer.

Abstract: Provided is a dispersion stabilizer for suspension polymerization comprising an aqueous emulsion containing a dispersant (A), a dispersoid (B), a graft polymer (C), and an aqueous medium, wherein the dispersant (A) contains a surfactant, the dispersoid (B) contains a polymer having an ethylenically unsaturated monomer unit, the graft polymer (C) is obtained by graft polymerization of the ethylenically unsaturated monomer with the dispersant (A), a mass ratio [A/(A+B+C)] is 0.001 or more and less than 0.18, a mass ratio [C/(A+B+C)] is 0 or more and less than 0.04, and the total content of the dispersant (A), the dispersoid (B), and the graft polymer (C) is 35 to 70 mass %. A vinyl polymer to be obtained by suspension polymerization of a vinyl compound using the dispersion stabilizer has good plasticizer absorption. Further, the number of fish-eyes that occur when the vinyl polymer is formed is small, and the hue deterioration is also suppressed.

Abstract: There is provided a dispersion stabilizer for suspension polymerization comprising a vinyl alcohol polymer (A), wherein the vinyl alcohol polymer (A) has a terminal anionic group and has a saponification degree of 30 to 60 mol %, a viscosity average polymerization degree of 650 or less, and a proportion of polymer molecules having a molecular weight of 8000 or less as determined by gel permeation chromatography is 9.5% by mass or less. When a vinyl compound is suspension-polymerized using the dispersion stabilizer for suspension polymerization, its higher polymerization stability allows for providing particles having a uniform size with a less amount of coarse particles, even under the conditions favorable for unstable polymerization.

Abstract: The present invention provides an easy-to-handle dispersion stabilizer for suspension polymerization that meets the following requirements: even if the amount of the dispersion stabilizer for suspension polymerization used for suspension polymerization of a vinyl compound is small, the resulting vinyl resin has high plasticizer absorptivity and is easy to work with; it is easy to remove residual monomer components from the resulting vinyl resin; and the resulting vinyl resin contains fewer coarse particles. The present invention relates to a dispersion stabilizer for suspension polymerization in the form of an aqueous liquid. This dispersion stabilizer contains, at a concentration of 20 mass % or more and 50 mass % or less, a PVA having a degree of saponification of 35 mol % or more and 65 mol % or less, a viscosity average degree of polymerization of 100 or more and 480 or less, a terminal aliphatic hydrocarbon group having 6 to 12 carbon atoms, and a block character of residual ester groups of 0.5 or more.

Abstract: The present invention provides a highly water-soluble and easy-to-handle dispersion stabilizer for suspension polymerization that meets the following requirements: even if the amount of the dispersion stabilizer for suspension polymerization used for suspension polymerization of a vinyl compound is small, the resulting vinyl resin has high plasticizer absorptivity and is easy to work with; it is easy to remove residual monomer components from the resulting vinyl resin; and the resulting vinyl resin contains fewer coarse particles. The present invention relates to a dispersion stabilizer for suspension polymerization of a vinyl compound. This dispersion stabilizer contains a vinyl alcohol polymer (A) having a degree of saponification of 20 mol % or more and less than 65 mol %, a viscosity average degree of polymerization (P) of 100 or more and less than 600, an aliphatic hydrocarbon group having 6 to 18 carbon atoms at its terminal, and an anionic group in its side chain.

Abstract: There is provided a dispersion stabilizer for suspension polymerization comprising a vinyl alcohol polymer (A), wherein the vinyl alcohol polymer (A) has a terminal anionic group and has a saponification degree of 30 to 60 mol %, a viscosity average polymerization degree of 650 or less, and a proportion of polymer molecules having a molecular weight of 8000 or less as determined by gel permeation chromatography is 9.5% by mass or less. When a vinyl compound is suspension-polymerized using the dispersion stabilizer for suspension polymerization, its higher polymerization stability allows for providing particles having a uniform size with a less amount of coarse particles, even under the conditions favorable for unstable polymerization.

Abstract: There is provided a dispersion stabilizer for suspension polymerization of a vinyl compound, which is composed of an aqueous emulsion, wherein the aqueous emulsion comprises a solid comprising (A) a polyvinyl alcohol, (B) a polyvinyl ester, and (C) a graft polymer produced by graft-polymerizing a vinyl ester monomer to a polyvinyl alcohol; wherein the amount of (A) the polyvinyl alcohol is 0.1 to 18% by mass based on the total amount of (A), (B) and (C); wherein the amount of (C) the graft polymer is 7 to 80% by mass based on the total amount of (A), (B) and (C); and wherein a weight-average molecular weight of the solid as determined by gel permeation chromatography is 1,100,000 or less. Such a dispersion stabilizer for suspension polymerization exhibits excellent polymerization stability and excellent handleability. In addition, a vinyl resin obtained using the dispersion stabilizer for suspension polymerization has good plasticizer absorbency.

Abstract: A dispersion stabilizer for suspension polymerization of vinyl compounds comprising a vinyl alcohol polymer (A) which has a saponification degree of 30 mol % or more and less than 60 mol % and a viscosity-average polymerization degree (P) of more than 200 and less than 600, and has a terminal alkyl group having 6 to 18 carbon atoms, and in which a content of monomer units having an oxyalkylene group is 0.3 mol % or less and the relationship between the viscosity-average polymerization degree (P) and a modification rate (S) (mol %) of the alkyl group satisfies Formula (1). Thus, there can be provided a dispersion stabilizer for suspension polymerization with which, during suspension polymerization of vinyl compounds including vinyl chloride, even when it is used in a small amount, the absorbency of a plasticizer is high, resulting in easy processing and formation of coarse particles is little and the remaining monomer components can be easily removed. 50?S×P/1.