Method for injection stretch blow molding of polyethylene
US5620650A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 18, 1994 |
| Grant date | Apr 15, 1997 |
| Priority date | — |
| Expiry date | Oct 18, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2623/06
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method enabling stretch blow molding in a temperature range preferable for polyethylene and capable of releasing at a surface temperature suited to both releasing of a preform and subsequent stretch blow molding, by disconnecting the core die and the preform in advance by the use of pressure of gas. The injection molding of a predetermined preform involves filling an injection mold with molten polyethylene, releasing the preform from the cavity die and core die of the injection mold while a mouth portion of the preform is held by the lip die, and transferring the preform into a blow die to stretch blow mold into a hollow molded thin wall product. Gas forcibly enters into the boundary of the core die and the preform, before releasing the preform from the injection mold to isolate the inside wall of the preform from the core die. Releasing is effected while the inside of the preform is not completely cooled and is still at high temperature, and in a temperature range in which the surface temperature of the preform right after releasing is 80 to 90 deg. C. The step of stretch blow molding is performed within the time interval before the surface temperature of the preform which is el…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.