| 摘要 |
PROBLEM TO BE SOLVED: To provide expandable polystyrene resin particles being capable of giving an expanded molding proof against exudation of oils and coloring matters and being excellent in expandability, to provide a method for producing the same, to provide an expanded molding obtained therefrom, and to provide a packaged food prepared by packaging food in the expanded molding. SOLUTION: The expandable polystyrene resin particles are characterized in that an outer layer of a polystyrene resin formed by polymerizing a styrene monomer containing a crosslinkable monomer is formed on the surface of a polystyrene resin particle, an easily volatile blowing agent is infiltrated into the particles, the gel fraction of the polystyrene resin constituting the particles is 10 to 50 mass%, the ratio (Mw<SB>1</SB>/Mw<SB>2</SB>) lies in the range of 0.5 to 0.8 (wherein Mw<SB>1</SB>is the weight-average molecular weight of the polystyrene resin extracted with tetrahydrofuran; and Mw<SB>2</SB>is the weight-average molecular weight of the polystyrene resin extracted after splitting each particle into two; and Mw<SB>2</SB>lies in the range of 150,000 to 400,000). COPYRIGHT: (C)2007,JPO&INPIT |
