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US 5,683,637 AGranted
Method of molding expandable styrene type resin particles
AssigneeSekisui Kaseihin Kogyo Kabushiki Kaisha
InventorsIkuo Morioka, Hiroyuki Yamagata, Mutsuhiko Shimada
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Abstract
A foamed article of styrene type resin, in which base resin particles are styrene type resin particles obtainable by a graft polymerization of a cis-rich polybutadiene with a styrene type monomer, a blowing agent contains n-pentane as its main component and the foamed article shows a density of 0.015-0.040 g/cm.sup.3, an average foam diameter of 60-300 micrometers and a closed cell foam rate of not less than 50%.
Claims3
A method of manufacturing a foamed article which comprises:
- suspending styrene resin particles having a weight average molecular weight of about 200,000 to 400,000, which have been formed by a graft polymerization of monomers comprising:
- cis-rich polybutadiene, having a cis content of at least about 80% by weight and
- a styrene monomer in an aqueous medium;
- impregnating a blowing agent comprising at least about 50% n-pentane,. into said resin particles at the temperature of 100.degree.-150.degree. C. to obtain expandable resin particles containing 3-10% by weight of the blowing agent admixed with the resin particles;
- pre-expanding the expandable particles;
- and
- molding the resulting pre-expanded particles in a mold to form said foamed article.
4 more elements
Dependencies are inferred from the claim text.