| 摘要 |
PROBLEM TO BE SOLVED: To obtain a thick low-density foam having a beautiful appearance by mixing (A) a modified PP(polypropylene) resin obtaied by reacting a PP resin with a monomer selected from among isoprene, etc., (B) a PS(polystyrene) resin, and (C) a hydrogenated styrene-butadiene block copolymer, each in a specified amount, with a blowing agent on an extruder and extruding the mixture into a low-pressure zone so as to impart specified density and closed cell content to the resultant foam. SOLUTION: A resin mixture comprising (A) 60-95 pts.wt. modified PP resin obtained by reacting a PP resin with a monomer selected from among isoprene, styrene, and l,3-butadiene in the presence of a free-radical polymerization initiator, (B) 40-5 pts.wt. PS resin, and (C) 0.5-15.0 pts.wt. (based on 100 pts.wt. sum of ingredients A and B) hydrogenated styrene-butadiene block copolyme is mixed with a blowing agent on an extruder and is extruded into a low-pressure zone to give a foam having a density of 50-10 kg/m3 and a closed cell content of 60% or higher. The resultant foam has a thickness of 20 mm or higher and an average cell size of 1.5 mm or lower. |
