Patent · US Expired

Molding process using gas under pressure

US5798063A · kind A · utility

7Cited by

4References

7Claims

0Family size

Assignee

E.I. DU PONT DE NEMOURS AND COMPANY · US

Inventors

Klaus Bender · Wehringen, DE
Philippe Leboeuf · Paris, FR
Georgios Topulos · Geneva, CH

Key dates

Filing date	Mar 27, 1997
Grant date	Aug 25, 1998
Priority date	—
Expiry date	Mar 27, 2017

Classification

Technology area (CPC B)Performing Operations; Transporting
CPC primaryB29C44/04
WIPO fieldOther special machines
WIPO sectorMechanical engineering

Abstract

A process for making injection molded articles having a substantially smooth outer surface and a foamed core by injecting a molten thermoplastic into a mold, and, when the outer surface has formed, injecting a gas under pressure into the mold whereby a limited amount of molten material flows back into the injection unit to create a hollow space in the core of the melt, and releasing the gas pressure to allow the core to foam.

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