Process for producing foamable polyethylene resin particles
AssigneeSekisui Kaseihin Kogyo Kabushiki Kaisha
InventorYoshiaki Kitamori
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Abstract
A process for producing foamable polyethylene resin particles which comprises suspending in an aqueous medium polyethylene resin particles having an MI value of 0.3 to 10, a density of less than 0.93 g/cm.sup.3 and a softening point below 90.degree. C., adding to the suspension 30 to 300% by weight based on the weight of the particles of a styrene monomer and a catalyst for polymerizing the monomer, polymerizing the monomer, and impregnating a blowing agent in the polyethylene resin particles containing the polymerized styrene resin to form foamable polyethylene resin particles.
Claims9
A process for producing foamable polyethylene resin particles which comprises the steps of:
- (a) suspending in an aqueous medium polyethylene resin particles having an MI value of 0.3 to 10, a density of less than 0.93 g/cm.sup.3 and a softening point below 90.degree. C.;
- (b) adding to said aqueous suspension 30 to 300% by weight based on the weight of said particles of a styrene monomer and a catalyst for polymerizing said monomer;
- (c) polymerizing said monomer in the interior of said polyethylene resin particles;
- and
- (d) impregnating, after the polymerization, a blowing agent into the resulting polyethylene resin particles which contain a polystyrene resin formed by the polymerization of said styrene monomer at a temperature below the softening point of said polyethylene resin particles, wherein said blowing agent does not substantially reduce the viscosity of the polymerization system, does not dissolve said resin particles or only slightly swells the polyethylene resin particles, said polyethylene resin particles exhibiting excellent foaming ability and blowing agent retention.
Dependencies are inferred from the claim text.