Patent ID: 8779017
Filing Date: 2014-07-15
Classification: B29C,C08J

Abstract:
1. A method of producing a foam comprising: preparing a molten resin composition which contains resin (A) having a glass transition temperature of higher than 50° C., particulate resin (B) immiscibly dispersed in resin (A), resin (B) having a glass transition temperature of lower than the glass transition temperature of resin (A) by 50° C. or more, and a foaming agent; and producing a foam by continuous extrusion foaming of the molten resin composition with an extruder equipped with a circular die, an internal pressure and a lip clearance of the circular die being 20 MPa or higher and 0.2 mm or less, respectively, wherein, during the continuous extrusion foaming, the foaming agent is allowed to foam in particulate resin (B) to form bubbles in the particulate resin (B) and wherein the particulate resin (B) in which bubbles are formed has a particle diameter of 10 μm or less, wherein the foam has a rupture strength of 12 MPa to 55 MPa when measured at 23° C., and wherein resin (A) is cyclic polyolefin resin, and resin (B) is polypropylene resin, polyethylene resin, or elastomer.