Dic Corporation

Dainippon Ink and Chemicals, Incorporated

Chikara Yoshioka

Takashi Yasumura

Yukiko Fujita

Kazutoshi Hitomi

Provided is a fiber-reinforced molding material containing a thickening substance (A) containing a vinyl ester resin (a1), an unsaturated monomer (a2), a polyisocyanate (a3), and a polymerization initiator (a4) as essential raw materials and carbon fibers (B) with a fiber length of 2.5 mm to 50 mm. The thickening substance (A) satisfies conditions (1) to (3) below as measured with a rheometer. (1) The maximum value of the rate of change in viscosity in a temperature region lower than a temperature Xa indicating the lowest melt viscosity A is 100 Pa·s/° C. to 1,500 Pa·s/° C. (2) The maximum value of the rate of change in viscosity in a temperature region higher than or equal to the temperature Xa is 1,000 Pa·s/° C. to 10,000 Pa·s/° C. (3) The lowest melt viscosity A is 10 Pa·s to 1,000 Pa·s and the temperature Xa is 70° C. to 140° C.

Fiber-reinforced molding material and molded article using same

A fiber-reinforced molding material includes: as essential raw materials, a vinyl ester (A) which is a reaction product of an epoxy resin (a1) having an epoxy equivalent in the range of 180 to 500 and a (meth)acrylic acid (a2); an unsaturated monomer (B) having a flash point of 100&#xb0; C. or higher; a thermoplastic resin (C); a polyisocyanate (D); a polymerization initiator (E); and carbon fibers (F) having a fiber length of 2.5 to 50 mm. The mass ratio ((A)/(B)) of the vinyl ester (A) to the unsaturated monomer (B) is in the range of 40/60 to 85/15. The molar ratio (NCO/OH) of the isocyanate group (NCO) of the polyisocyanate (D) to the hydroxy group (OH) of the vinyl ester (A) is in the range of 0.25 to 0.85.

A process for producing an unsaturated polyester comprising the steps of (1) (A)depolymerizing polyethylene terephthalate with a polyhydric alcohol, (B) adding maleic anhydride to the depolymerization product to allow them to react with each other, and (C) adding dicyclopentadiene to the reaction mixture to cause addition reaction and (2) adding a polyhydric alcohol and a polybasic acid to the reaction product obtained in step (1) to cause polycondensation reaction is disclosed. An unsaturated polyester resin composition comprising the unsaturated polyester and a polymerizable unsaturated monomer, and a molding compound comprising the unsaturated polyester resin composition are also disclosed.

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Osaka, Japan

Chikara Yoshioka