The invention relates to a polymer structure (1) formed by at least a polymer, wherein said structure (1) comprises a volume (2) and a surface (3), wherein said polymer comprises a plurality of polymer chains connected by linkings, characterized by a linking density, wherein said linking density increases, particularly monotonously, from the surface (3) into the volume (2) of the polymer structure (1).

A group of polyfunctional oxetane-based compounds having a structure as represented by general formula (I) or a product obtained by a reaction between a compound of general formula (I) and epichlorohydrin, an ester compound, or an isocyanate compound. When these polyfunctional oxetane-based compounds are used as cation polymerizable monomers in combination with an epoxy compound, the curing speed is high, and the cured product has highly excellent hardness, flexibility, adherence, and heat resistance.

A cured product of a resin composition according to the present invention includes at least silsesquioxane. When the average thermal expansion coefficient of the cured product at 30 to 200 C. is expressed as 1 [K.sup.1], at least one of requirements 1/210 and (12).sup.210.sup.80.4 is satisfied, where a reference value 2 is 35010.sup.6 [K.sup.1] or less. In the cured product, an absorbance derived from a siloxane bond, an absorbance derived from a hydrocarbon group, and an absorbance derived from a hydroxy group are respectively expressed as Ia, Ib, and Ic, the absorbances being determined by attenuated total reflection using a Fourier transform infrared spectrophotometer. In this case, requirements 0.09Ia/Ib3.0 and 0.04Ic/Ib1.0 are satisfied.

A cured product of a resin composition according to the present invention includes at least silsesquioxane. When the average thermal expansion coefficient of the cured product at 30 to 200 C. is expressed as 1 [K.sup.1], at least one of requirements 1/210 and (12).sup.210.sup.80.4 is satisfied, where a reference value 2 is 35010.sup.6 [K.sup.1] or less. In the cured product, an absorbance derived from a siloxane bond, an absorbance derived from a hydrocarbon group, and an absorbance derived from a hydroxy group are respectively expressed as Ia, Ib, and Ic, the absorbances being determined by attenuated total reflection using a Fourier transform infrared spectrophotometer. In this case, requirements 0.09Ia/Ib3.0 and 0.04Ic/Ib1.0 are satisfied.

Provided are: a core-corona polymer particle excellent in emulsion stability and feeling of use, and a raw material for a cosmetic and an oil-in-water emulsion cosmetic comprising the particle. Certain embodiments of the present invention provide a core-corona polymer particle obtained by radical-polymerizing a polyethylene oxide macromonomer represented by formula (1) and one or two or more of hydrophobic monomers represented by formulas (2) and (3) under conditions (A) to (D).

Provided are: a core-corona polymer particle excellent in emulsion stability and feeling of use, and a raw material for a cosmetic and an oil-in-water emulsion cosmetic comprising the particle. Certain embodiments of the present invention provide a core-corona polymer particle obtained by radical-polymerizing a polyethylene oxide macromonomer represented by formula (1) and one or two or more of hydrophobic monomers represented by formulas (2) and (3) under conditions (A) to (D).

Provided is a release agent for vulcanized rubber molding, the release agent exhibiting good mold releasability between a mold and a rubber after vulcanization and capable of being easily removed after production. The release agent for vulcanized rubber molding contains a polyoxyalkylene glyceryl ether (A). The polyoxyalkylene glyceryl ether (A) contains 50% to 95% by mass of oxyethylene groups in 100% by mass of oxyalkylene groups. The polyoxyalkylene glyceryl ether (A) preferably has a number-average molecular weight of 2,000 to 20,000.

Provided is a release agent for vulcanized rubber molding, the release agent exhibiting good mold releasability between a mold and a rubber after vulcanization and capable of being easily removed after production. The release agent for vulcanized rubber molding contains a polyoxyalkylene glyceryl ether (A). The polyoxyalkylene glyceryl ether (A) contains 50% to 95% by mass of oxyethylene groups in 100% by mass of oxyalkylene groups. The polyoxyalkylene glyceryl ether (A) preferably has a number-average molecular weight of 2,000 to 20,000.

To provide a polyether polyol having a high degree of freedom in the design of a polyurethane foam, and capable of providing a polyol system solution excellent in storage stability.

A polyether polyol having a polyoxyalkylene chain consisting of oxyalkylene units, and having a degree of unsaturation of at most 0.020 meq/g, a hydroxy value of from 1 to 80 mgKOH/g, a content of oxyethylene units of from 0 to 50 mass %, and a content of ultra-high molecular weight components which have molecular weights of from 12 to 46 times the number average molecular weight of at most 1,000 mass ppm. The number average molecular weight is a molecular weight as calculated as polystyrene measured by gel permeation chromatography (GPC) method, and the content of ultra-high molecular weight components is a value measured by high performance liquid chromatography (HPLC) method using a charged aerosol detector (CAD).

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.