Kureha Corporation

Kureha Kagaku Kogyo K.k.

Kureha Kagaku K.k.

Tetsuo Ejiri

Shunzo Endo

Yasuhiro Suzuki

Yoshikatsu Satake

Kazuyuki Yamane

Mitsuhiro Matsuzaki

Genzo Asai

Kentaro Otawara

Shintaro Nomura

Naoko Kuriu

Object: To provide thermally expandable microspheres having little sag. Resolution Means: The thermally expandable microspheres have a structure in which a foaming agent is encapsulated in an outer shell formed from a polymer, wherein, the ratio (%) of (R2/R1)&#xd7;100 is at least 105%, where R1 is the expansion ratio after the thermally expandable microspheres have been heat-treated for 5 minutes at 150&#xb0; C. and then foamed by heating for 2 minutes at 200&#xb0; C., and R2 is the expansion ratio after the thermally expandable microspheres have been heat-treated for 5 minutes at 150&#xb0; C. and then foamed by heating for 4 minutes at 200&#xb0; C.

Thermally-expandable microspheres, and composition and molded article containing same

This invention aims to provide a thermally foamable microsphere which is excellent in heat resistance, has a high expansion ratio, and shows stable foaming behavior; a method of producing the thermally foamable microsphere; and suitable use thereof. This invention provides a thermally foamable microsphere in which an outer shell encapsulating a foaming agent is formed of a copolymer having a polymethacrylimide structure. In particular, this invention provides a thermally foamable microsphere in which monomers capable of forming the polymethacrylimide structure by a copolymerization reaction are methacrylonitrile and methacrylic acid. Moreover, this invention provides a method of producing the thermally foamable microsphere and use of the thermally foamable microsphere as an additive.

Thermally foamable microsphere, method of producing the same, and use thereof

A thermally foamable microsphere having a structure that a foaming agent is encapsulated in an outer shell formed from a polymer, wherein the foaming agent contains isododecane, and a production process of the thermally foamable microsphere by a suspension polymerization process using a polymerizable monomer and a foaming agent containing dodecane.

Thermally foamable microsphere, production method thereof, use thereof, composition containing the same, and article

A method of refining a crystal of a crude cyclic ester comprises the steps of supplying the crude cyclic ester to a vertically extending cylindrical refiner ( ) from an inlet ( ) provided at a lower part of the refiner ( ), agitating the crude cyclic ester by an agitator provided in the refiner ( ) to make the crude cyclic ester flow upwardly, refining the crystals of the crude cyclic ester by counterflow-contact between the upflowing crude cyclic ester and a downflowing melted liquid containing a refined crystal component, and taking out refined crystals of the crude cyclic ester from an outlet ( ) provided at an upper part of the refiner ( ).

Method for purification of cyclic ester

Foamable microspheres with a foaming agent enclosed in the shell of a polymer, wherein the average particle diameter of the microspheres is within a range of 3 to 100 &mgr;m, and the coefficient of variation of the particle diameter distribution thereof is at most 1.50%, and production process of foamable microspheres by a suspension polymerization process.

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Tokyo, Japan

Tetsuo Ejiri