Nippon Oil Fats Co., Ltd.

Kyosuke Fukushi

Masaharu Nakayama

Yasuo Moriya

Nobuyoshi Suzuki

Kazuo Matsuyama

Norihisa Ujikawa

Kenji Nagai

A low-profile unsaturated polyester resin composition, consisting essentially of (A) an unsaturated polyester, (B) a monomer copolymerizable with the unsaturated polyester, and (C) an A-B type block copolymer comprising an A segment which is a product using vinyl acetate and butyl acrylate as raw materials and a B segment which is a product solely of styrene or a product using styrene and a monomer copolymerizable with styrene as raw materials.

Low-profile unsaturated polyester resin composition

A plastic lens which has high hardness and excellent scratch resistance and can form a transparent and uniform reflection preventing film through vacuum deposition, is produced by mixing

Method for producing a plastic lens

Disclosed herein is a low shrinkable unsaturated polyester resin composition consisting of (A) 20-70% by weight of an unsaturated polyester, (B) 28-60% by weight of a monomer polymerizable with the above unsaturated polyester, and (C) 2-20% by weight of a block copolymer mixture. The mixtures of the monomer (B) and the block copolymer mixture (C), and a mixture of the polyester (A), the monomer (B), and the block copolymer mixture (C) are in a non-aqueous dispersion state. The block copolymer mixture is obtained by polymerizing either one of the monomers defined below in (a) and (b) with a polymerization initiator a polymeric perioxide represented by the formula: ##STR1## in which R.sub.1 represents a divalent branched hydrocarbon group having 10-30 carbons, and R.sub.2 and R.sub.3 represent a hydrogen atom, a hydroxyl group or an alkali metal, and the average polymerization degree n is 2-40, and is used to obtain a first polymer having peroxy bonds in its molecule, and block-polymerizing the first polymer with the remaining monomer (a) or (b) which has not been used in the first polymerization reaction wherein, (a) is a monomer or a monomer mixture consisting of 70-100% by weight of styrene monomer and 30-0% by weight of a monomer polymerizable therewith.

Low shrinkable unsaturated polyester resin composition

An unsaturated polyester resin composition comprising an unsaturated polyester resin, a polymerizable monomer and a mixture of block copolymers having acid groups prepared by first copolymerizing in a first copolymerization reaction a polymeric peroxide with a monomer A or B, or with an unsaturated acid together with monomer A or B, thereby obtaining a copolymer having peroxy bonds in the molecule thereof, which copolymer is further copolymerized in the second copolymerization reaction with each of monomers A or B or the unsaturated acid which were excluded in the first copolymerization reaction to give the block copolymer mixture, which composition shows no segregation of the low shrinkage agent on thickening by a thickener and the said composition gives cured moldings of reduced shrinkage which are excellent in many characteristics.

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Kuwana, Japan

Kyosuke Fukushi