Patent ID: 8592494
Filing Date: 2013-11-26
Classification: C08F,C08J,C08L,Y10T

Abstract:
1. A method for producing an auto-part or cushioning part, comprising: dispersing 100 parts by weight of non-crosslinked linear low-density polyethylene-based resin particles which are polymerized using a metallocene compound as a catalyst and contain an inorganic nucleating agent, 30 to 300 parts by weight of a styrene-based monomer and 0.1 to 0.9 parts by weight of a polymerization initiator relative to 100 parts by weight of the styrene-based monomer into an aqueous suspension containing a dispersant; impregnating the polyethylene-based resin particles with the styrene-based monomer by heating a resulting dispersion at such a temperature that the styrene-based monomer does not substantially polymerize; performing first polymerization of the styrene-based monomer at a temperature of (T+10) to (T+35)° C., T° C. being a crystallization peak temperature of the polyethylene-based resin particles; subsequent to the first polymerization, adding a styrene-based monomer and 0.1 to 0.9 parts by weight of a polymerization initiator relative to 100 parts by weight of the styrene-based monomer and adjusting the temperature of the resulting dispersion to (T+10) to (T+35)° C., T° C. being a crystallization peak temperature of the polyethylene-based resin particles, so that impregnation ofthe polyethylene-based resin particles with the styrene-based monomer and second polymerization take place, wherein the total amount of the styrene-based monomers used in the first and second polymerization is 50 to 800 parts by weight relative to 100 parts by weight of the polyethylene-based resin particles; impregnating the styrene-modified resin particles with a volatile blowing agent to obtain expandable styrene-modified resin particles; pre-expanding the expandable styrene-modified resin particles to obtain pre-expanded styrene-modified resin particles; and heating the pre-expanded styrene-modified resin particles in a mold to obtain the auto-part or cushioning part having a falling ball impact value of 80 cm or greater and a density of 10 to 300 kg/m