Kuraray Co., Ltd.

Koji Kitayama

Kei Hirata

Mizuho Maeda

Kazushige Ishiura

Kenichi Hamada

Makoto Akai

A curable composition includes (A) a (meth)acrylate, (B) a radical polymerization initiator, (C) an epoxidized polyisoprene containing an epoxy group at 0.15 to 2.5 meq/g in the molecule and having a number-average molecular weight of 15000 to 200000, and (D) a curing accelerator. The curable composition shows high elongation and excellent rubber elasticity even in a cured state and has superior compatibility, transparency, waterproofness and flexibility, so that cracks and separation of cured products are reduced. Accordingly, the composition is suitable for use as adhesives, coating agents, encapsulating materials, inks, sealing materials and the like.

Curable composition

An epoxy resin composition includes (A) an epoxy resin, (B) a curing agent, and (C) an epoxidized polyisoprene (c-1) that contains an epoxy group at 0.15 to 2 meq/g in the molecule and has a number-average molecular weight of 15000 to 200000 or an epoxidized polybutadiene (c-2) that contains an epoxy group at 0.15 to 2 meq/g in the molecule and has a number-average molecular weight of 20000 to 200000. The epoxy resin composition has high heat resistance and reduced internal stress, and can be suitably used in applications such as electronic part materials represented by semiconductor encapsulating materials and adhesives.

Epoxy resin composition

A curable resin composition includes (A) a cationically polymerizable-compound, (B) a cationic photopolymerization initiator, and (C) an epoxidized polyisoprene containing an epoxy group at 0.15 to 2.5 meq/g in the molecule and having a number-average molecular weight of 15000 to 200000. The curable resin composition shows excellent elongation properties and high break elongation even in a cured state and can give a cured product having superior compatibility, transparency, flexibility and waterproofness. Accordingly, the composition is suitable for use as adhesives, coating agents, encapsulating materials, inks, sealing materials and the like.

Curable resin composition

A block copolymer comprising, in a main chain thereof, a crystalline polymer block A obtained by hydrogenation of at least 80% of unsaturated bonds of a butadiene-based polymer block having a 1,2-bond content less than 20%, a polymer block B having a glass transition point of 20&deg; C. or lower and a polymer block C composed mainly of a methacrylate ester unit and/or an acrylate ester unit and having a glass transition point exceeding 20&deg; C. has good elastomeric properties, excellent weather resistance, solvent resistance and heat resistance and has good affinity with each of a polar polymer and non-polar polymer. A polymer composition comprising said block copolymer effectively exhibits the above-described characteristics of the block copolymer.

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Ibaraki, Japan

Koji Kitayama