| 摘要 |
<p>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 have a large cell size (>=1.5 mm), are open or closed-cell foams, and preferably have at least one perforation per square centimeter and/or a density less than 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 weight 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.</p> |
