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: 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: 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: There is provided a dispersing agent for suspension polymerization of a vinyl compound comprising a polyvinyl alcohol with a saponification degree of 65 to 90 mol % which satisfies Formulas (1) to (3). It allows for reducing the amount of coarse particles during polymerization and can thus provide a vinyl polymer with a sharp particle size distribution and higher plasticizer absorbability. 0.4?(MwUV/MwRI)?0.95??(1) 3?(MwUV/MnUV)?12??(2) 0.1?A220?0.

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: Provided by the present invention is a vinyl alcohol polymer crosslinked by a structure represented by the following formula (1) and/or a disulfide structure, in which the vinyl alcohol polymer is not completely dissolved in a mixture prepared by: adding the vinyl alcohol polymer to water so as to give a concentration of 4% by mass; and stirring at 95° C. for 3 hrs. in the formula (1), R1, R2 and R3 each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 8 or less carbon atoms. Also provided include an additive for a drilling mud containing the vinyl alcohol polymer, a drilling mud containing the vinyl alcohol polymer as an additive, an additive for a drilling cement slurry containing the vinyl alcohol polymer, and a drilling cement slurry containing the vinyl alcohol polymer as an additive.

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: The present invention addresses the problem of providing a composite paper which exhibits excellent oil resistance, water vapor permeability, and water resistance even when hot and oily food is wrapped therein. The above problem can be solved by using a composite paper comprising an oil-resistant layer formed on at least one surface of a base paper, wherein the oil-resistant layer comprises a vinyl alcohol polymer (A) having a content of ethylene units of 2 to 10 mol %, a viscosity-average degree of polymerization of 300 to 2000, a saponification degree of 95 to 99.5 mol %, a total content of carboxyl groups and lactone rings of 0.02 to 3 mol %, a melting point of 180 to 230° C., a content of 1,2-glycol bonds of 1.2 to 2 mol %, and a molar fraction of central hydroxyl groups in chains of three consecutive hydroxyls by a triad expression relative to vinyl alcohol units of 65 to 98 mol %, the base paper has an air permeability resistance of 1000 seconds or less and a bulk density of 0.5 to 1.

Abstract: Provided is a vinyl alcohol-based copolymer, obtained by saponifying a copolymer of vinyl acetate and a polyfunctional monomer, wherein the polyfunctional monomer contains two or more ethylenic double bonds in its molecule, the vinyl alcohol-based copolymer has a side chain containing an ethylenic double bond and a molar ratio (d) of the ethylenic double bond to a total of vinyl alcohol units and vinyl acetate units is from 0.05/100 to 2/100, and the vinyl alcohol-based copolymer is water soluble.

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: Provided is greaseproof paper that, when folded, shows little reduction in grease resistance at the folded portion. The greaseproof paper includes a paper base and a greaseproof layer provided on at least one surface of the paper base, wherein the greaseproof layer includes an ethylene-vinyl alcohol-vinyl ester copolymer (A) and a fatty acid derivative (B), contains 1 to 100 parts by mass of the component (B) per 100 parts by mass of the component (A), and is in an amount of 0.5 to 5.0 g/m2 in terms of dry mass. In the greaseproof paper, the ethylene-vinyl alcohol-vinyl ester copolymer (A) has a content of ethylene units of 1 to 15 mol %, has a total content of vinyl alcohol units and vinyl ester units of 85 to 99 mol %, and has a degree of polymerization of 300 to 2000. In the greaseproof paper, the fatty acid derivative (B) is a fatty acid amide compound.

Abstract: The synthesis of fluoropolyarylene ether with a high degree of polymerization is enabled, by using a copper complex catalyst with an oxidation potential in the range of −1V to 2V, for the oxidative polymerization of fluorophenols that contain at least one hydrogen atom as well as a fluorine atom bonded to the carbon atoms constituting the benzene ring.