| 摘要 |
<p>Foaming by extruding, a composition of a polyethylene resin and a foaming agent, the latter comprising dichlorodifluoromethane (I) and at least one aliphatic hydrocarbon or chlorofluorohydrocarbon having bp 0 to 80 degrees C (II); or (I) and monochloropentafluoroethane and/or octofluorocyclobutane (III); or (I) and (II) and (III); that foaming agent having a saturation vapour pressure of less than 25 kg/cm2 at 100 degrees C. Foams produced are resilient; the foaming rate is high; the surface of the foamed product is smooth, without creases or hollows as there is no contraction of the foam, once produced, process is simple. Foams may be extruded to form tubes, rods, films etc.</p> |
