PROCESS FOR MAKING ETHYLENIC POLYMER FOAM STRUCTURES

摘要

Disclosed is an ethylenic polymer foam structure comprising an ethylenic polymer material. The ethylenic polymer material contains a substantially linear ethylenic polymer having: a) a melt flow ratio, 110/12 ? 5.63; b) a molecular weight distribution, Mw/Mn, defined by the equation Mw/Mn ? (110/12)-4.63; and c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear olefin polymer having about the same 12 and Mw/Mn. The foam structures have toughness and elasticity similar to those formed from conventional LLDPE without the poor dimentional stability and foam quality associated with those structures. The foam structures have foam quality similar to those made with conventional LDPE but with enhanced toughness and elasticity. Further disclosed is a process for making the above foam structure and making it in a foam bead form. Further disclosed is a process for making an article of the foam beads.