Kaneka Corporation

Taro Kiguchi

Kenichi Senda

Kenji Yamaguchi

Masahiko Sameshima

Tomonori Iwamoto

Kirito Suzuki

Tsuyoshi Kobayashi

Takashi Hamamoto

Expandable methyl methacrylate resin particles having a narrow particle size distribution, a good yield, and excellent expandability and formability are provided. The expandable methyl methacrylate resin particles include a base resin containing, as constitutional units, a certain amount of a methyl methacrylate unit and a certain amount of acrylic ester unit, and a blowing agent. The expandable methyl methacrylate resin particles have an average particle diameter of 0.6 mm to 1.0 mm and a particle diameter variation coefficient of not more than 20%.

Expandable methyl methacrylate resin particles, methyl methacrylate resin pre-expanded particles, methyl methacrylate expansion-molded body, and method for producing expandable methyl methacrylate resin particles

The present invention provides pre-expanded polypropylene resin beads comprising (A) a glycerin monoester of a Cto Cfatty acid and/or a polyglycerin monoester of a Cto Cfatty acid and (B) a glycerin diester of a Cto Cfatty acid(s) and/or a polyglycerin diester of a Cto Cfatty acid(s), in such a manner that a weight ratio [=(A)/(B)] between (A) and (B) in the polypropylene resin particles is 1.3 or more but 10 or less, and a total content [=(A)+(B)] is 0.3 parts by weight or more but 5 parts by weight or less with respect to 100 parts by weight of the polypropylene resin. The resin particles can be excellently used in in-mold foaming, without requiring washing with a chemical like nitric acid or metaphosphate soda, and can provide a polypropylene resin in-mold foamed product with good antistatic properties.

Pre-expanded polypropylene resin beads and process for producing same

An object of the present invention is to provide an in-mold foamed article having good surface appearances and high rigidity produced by using a common molding machine that withstands a pressure of up to 0.4 MPa. The present invention provides polypropylene resin pre-expanded particles containing a base resin which is a resin having a melt flow rate of 5 g/10 min or more and 20 g/10 min or less and a melting point of 140&#xb0; C. or higher and 155&#xb0; C. or lower and satisfying the conditional formula below, and an in-mold foamed article produced from molding the pre-expanded particles:[Heat of crystal fusion (J/g)]&#x2267;1.2&#xd7;[Melting point (&#xb0; C.)]&#x2212;96.

Polypropylene resin pre-expanded particles and in-mold foamed articles prepared therefrom

Polyolefin resin pre-expanded particles having two fusion peaks on DSC curve wherein the proportion of the heat of fusion Qh of the peak appearing on the high temperature side based on the total heat of fusion of the two peaks represented by the equation: &lsqb;Qh/(Ql&plus;Qh)&rsqb;&times;100 falls within the range of 10 to 60% in which Ql is the heat of fusion of the peak appearing on the low temperature side, and the standard deviation of said proportion is not more than 1.2. The pre-expanded particles are prepared by releasing an aqueous dispersion of resin particles impregnated with a blowing agent from a vessel into an atmosphere of lower pressure than the inner pressure of the vessel to expand the particles, while stepwise or continuously raising the inner temperature or the inner pressure of the vessel at a specific rate, and can be molded with stable molding cycle to give cellular molded articles having stable dimensions.

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Settsu, Japan

Taro Kiguchi