Process for preparing biaxially oriented hollow shaped articles from thermoplastic materials
US4385089A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 4, 1980 |
| Grant date | May 24, 1983 |
| Priority date | — |
| Expiry date | Mar 4, 2000 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/1397
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A process for preparing biaxially oriented hollow shaped articles, in particular bottles of thermoplastic material, by biaxial draw- and blow-molding comprises blow-molding a preform and subsequently maintaining the thermoplastic material in close contact with the hot walls of the mold at a temperature which is in the range from about the minimum effective temperature for biaxial orientation of the thermoplastic material to about 40.degree. C. above this temperature for a period of time which is sufficient to partially reduce internal residual stresses in the hollow shaped articles. Following this partial thermo-stabilization, the hollow shaped article preferably is subjected to cooling, whereby the pressure within the article is at least partially maintained or the shaped article is cooled or allowed to shrink and subsequently subjected to a second blow-molding procedure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.