Patent · US Expired

Process for post-expansion of pre-expanded polyolefins beads

US5830922A · kind A · utility

4Cited by

4References

14Claims

0Family size

Assignee

Huels Aktiengesellschaft · DE

Inventors

Reinhard Wirobski · Marl, DE
Bernd Guenzel · Haltern am See, DE

Key dates

Filing date	Feb 20, 1998
Grant date	Nov 3, 1998
Priority date	—
Expiry date	Feb 20, 2018

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10S264/09
WIPO fieldOther special machines
WIPO sectorMechanical engineering

Abstract

Partially expanded polyolefin granules are post-expanded by a process comprising charging a vessel containing foamed polyolefin beads having a bulk density of from 20-450 g/l with an inert gas under a pressure of from 2-25 bar and at a temperature of from T.sub.m -150.degree. C. to T.sub.m -40.degree. C. over a period of from 1-48 h, and then continuously or discontinuously transferring the pressurized foam beads into an apparatus in which a fluidized bed is created, where the beads expand further at a temperature of from T.sub.m -75.degree. C. to T.sub.m +20.degree. C. The resultant foamed beads are suitable for producing foamed moldings.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.