Method for reducing the aging period of polyethylene foams
US4272468A · kind A · utility
6Cited by
6References
9Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jun 18, 1979 |
| Grant date | Jun 9, 1981 |
| Priority date | — |
| Expiry date | Jun 18, 1999 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/15
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
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.degree. 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.