A water-absorbent copolymer may include a vinyl alcohol constituent unit x and a constituent unit z other than the vinyl alcohol constituent unit x and a vinyl ester constituent unit y, wherein a ratio of a content of an average sequence of the constituent unit z to a content of the constituent unit z is 50.0 mol % or less.

A water-absorbent copolymer may include a vinyl alcohol constituent unit x and a constituent unit z other than the vinyl alcohol constituent unit x and a vinyl ester constituent unit y, wherein a ratio of a content of an average sequence of the constituent unit z to a content of the constituent unit z is 50.0 mol % or less.

A modified PVA that enables formation of a film superior in cold water solubility, mechanical strength, and chemical resistance is provided. The modified PVA comprises a monomer unit represented by formula (I), and a structural unit represented by formula (II):

##STR00001##

wherein: a content of the monomer unit (I) is from 0.05 mol % to 10 mol %, and a content of the structural unit (II) is from 0.001 mol % to 0.5 mol % with respect to the total monomer units in the modified PVA; a viscosity average degree of polymerization is from 300 to 3,000; and a degree of saponification is from 82 mol % to 99.5 mol %. In the formula (I): R.sup.1 represents a hydrogen atom, or a methyl group; and R.sup.2 represents —R.sup.3—SO.sub.3.sup.−X.sup.+, —R.sup.3—N.sup.+(R.sup.4).sub.3Cl.sup.−, or a hydrogen atom, R.sup.3 representing an alkanediyl group, X.sup.+ representing a hydrogen atom, a metal atom, or an ammonium group, and R.sup.4 representing an alkyl group.

A modified PVA that enables formation of a film superior in cold water solubility, mechanical strength, and chemical resistance is provided. The modified PVA comprises a monomer unit represented by formula (I), and a structural unit represented by formula (II):

##STR00001##

wherein: a content of the monomer unit (I) is from 0.05 mol % to 10 mol %, and a content of the structural unit (II) is from 0.001 mol % to 0.5 mol % with respect to the total monomer units in the modified PVA; a viscosity average degree of polymerization is from 300 to 3,000; and a degree of saponification is from 82 mol % to 99.5 mol %. In the formula (I): R.sup.1 represents a hydrogen atom, or a methyl group; and R.sup.2 represents —R.sup.3—SO.sub.3.sup.−X.sup.+, —R.sup.3—N.sup.+(R.sup.4).sub.3Cl.sup.−, or a hydrogen atom, R.sup.3 representing an alkanediyl group, X.sup.+ representing a hydrogen atom, a metal atom, or an ammonium group, and R.sup.4 representing an alkyl group.

Disclosed pressure sensitive adhesive compositions, having enhanced heat resistance, obtained by the emulsion polymerization of (a) one or more acrylic acid ester or (meth)acrylate acid ester(s), (b) one or more hydroxyl functional (meth)acrylic monomer and (c) one or more ureido substituted (meth)acrylate monomers(s).

Disclosed pressure sensitive adhesive compositions, having enhanced heat resistance, obtained by the emulsion polymerization of (a) one or more acrylic acid ester or (meth)acrylate acid ester(s), (b) one or more hydroxyl functional (meth)acrylic monomer and (c) one or more ureido substituted (meth)acrylate monomers(s).

An acrylic emulsion pressure-sensitive adhesive composition is provided. The pressure-sensitive composition includes a copolymer which is prepared by emulsion polymerization of a monomer mixture in the presence of a polymeric emulsifier. The pressure-sensitive adhesive composition exhibits an excellent adhesive force to both hydrophobic and hydrophilic base materials while leaving less residue is provided.

An acrylic emulsion pressure-sensitive adhesive composition is provided. The pressure-sensitive composition includes a copolymer which is prepared by emulsion polymerization of a monomer mixture in the presence of a polymeric emulsifier. The pressure-sensitive adhesive composition exhibits an excellent adhesive force to both hydrophobic and hydrophilic base materials while leaving less residue is provided.

An object of the present invention is to provide a dispersion stabilizer for suspension polymerization which satisfies various performance requirements for suspension polymerization of a vinyl-based compound such as vinyl chloride. The present invention relates a modified vinyl alcohol-based polymer having at least one monomer unit represented by a following general formula (I) and a modification rate of from 0.01 mol % to 10 mol %: general formula (1) ##STR00001##
in which BO represents an oxybutylene unit; EO represents an oxyethylene unit; and each of m and n is a number of repeating unit of the respective oxyalkylene units; 1m10; and 1n60.

An object of the present invention is to provide a dispersion stabilizer for suspension polymerization which satisfies various performance requirements for suspension polymerization of a vinyl-based compound such as vinyl chloride. The present invention relates a modified vinyl alcohol-based polymer having at least one monomer unit represented by a following general formula (I) and a modification rate of from 0.01 mol % to 10 mol %: general formula (1) ##STR00001##
in which BO represents an oxybutylene unit; EO represents an oxyethylene unit; and each of m and n is a number of repeating unit of the respective oxyalkylene units; 1m10; and 1n60.