| 摘要 |
<p>Disclosed is a process for making extruded, closed-cell alkenyl aromatic polymer foam structure having an average cell size of from 0.3 to 3.0 millimeters. The process comprises: (a) heating an alkenyl aromatic polymer material having greater than 50 percent by weight alkenyl aromatic monomeric units to form a melt polymer material; (b) incorporating into the melt polymer material at an elevated pressure a blowing agent comprising at least 50 percent by weight 1,1-difluoroethane (HFC-152a) based upon the total weight of the blowing agent to form a foamable gel; (c) cooling the foamable gel to an optimum foaming temperature prior to extrusion through a die; and (d) extruding the foamable gel through a die to form the foam structure. Further disclosed is a foam structure made according to the above process.</p> |
