Forming molecularly oriented containers from reheated preforms
US4131666A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 25, 1977 |
| Grant date | Dec 26, 1978 |
| Priority date | — |
| Expiry date | Oct 25, 1997 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2633/18
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In forming containers from injection molded preforms of thermoplastic material such as nitrile-based polymers by a process which includes heating the preforms to orientation temperature followed by distension to container form in a mold, the improvement providing reduced thickness variability in lower portions of the containers which involves controlling preform shrinkage during such heating to between about 4 to 15% of the initial length for nitrile materials by maintaining the ratio of average thickness to inside preform surface area within defined limits and then axially and radially stretching such preforms during distension to predetermined levels. Nitrile preforms convertible to such improved quality containers have values of between about 0.005 to 0.011 inch.sup.-1 for the aforementioned ratio.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.