Blow-molded foam and process for producing the same
US6432525B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 17, 2000 |
| Grant date | Aug 13, 2002 |
| Priority date | — |
| Expiry date | May 17, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/249992
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In the present invention, for the production of a blow-molded foam, there is used a base resin which is mainly composed of a polypropylene resin and has, at 230° C., a melt tension (MT) of 10 gf or over and a melt flow rate (MFR) of 0.5 g/10 minutes or over. A foaming agent is added to the base resin, followed by melt kneading by means of an extruder under high temperature and high pressure conditions to provide a foamable melt. This melt is subjected to extrusion from a circular die 5 and expanded to form a cylindrical foamed parison 4. Thereafter, molds 6, 6 are clamped, and the parison 4 in a softened condition is placed in the molds 6, 6, and a pressurized gas is blown into the parison 4 from a gas blowing port 7 for blow molding in the form of a hollow shape conforming to the mold profile to produce a blow-molded foam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.