| 摘要 |
Macrocellular polyolefin foams that can withstand temperatures above 110 ~C are described for use in sound absorption and insulation applications, especially in elevated temperature and/or moist environments. These foams ha ve a large cell size (>= 1.5 mm), are open or closed-cell foams, and prefera bly have at least one perforation per square centimeter and/or a density less th an 25 kg/m3. They are obtainable by extruding a high melt strength (HMS) polypropylene resin (PP), or preferably a blend of a HMS PP resin and a free radical polymerized ethylene polymer present in the blend in a weigth ratio of at least 35:65, optionally another polymer such as a substantially random interpolymer, a cell size enlarging agent such a glycerol monostearate, an antioxidant, carbon black and/or flame retardant additives, using a volatile organic compound, e.g. isobutane, as blowing agent.
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