| 摘要 |
A method for reducing the aging period of foams produced using a gaseous expansion agent is disclosed which includes biaxial orientation of the thermoplastic polymer foam. The foam is cooled after it is extruded and blown up from a tubular die, the cooling being to a temperature at least 40 DEG C. below its melting point. Thereafter, the foam is biaxially oriented to a dimension at least 25% greater in both radial and axial directions than the dimensions of the extruded, blown up, cooled foam.
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