Foam structures of ethylenic polymer material having enhanced toughness and elasticity and process for making
US5340840A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 28, 1993 |
| Grant date | Aug 23, 1994 |
| Priority date | — |
| Expiry date | Apr 28, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S526/943
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
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, I.sub.10 I.sub.2, .gtoreq.5.63; b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-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 I.sub.2 and M.sub.w /M.sub.n. The foam structures have toughness and elasticity similar to those formed from conventional LLDPE without the poor dimensional 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.