Retortable packages
US4735339A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 26, 1987 |
| Grant date | Apr 5, 1988 |
| Priority date | — |
| Expiry date | May 26, 2007 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB65D77/2024
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A retortable, hydraulically solid, sealed package (10) containing a liquid or semi-liquid food product (24) comprises a thermoplastics container (12) formed by a thermo-forming process and a heat-shrinkable thermoplastics closure diaphragm (20). The closure diaphragm is heat-sealed to a rim (18) of the container after the headspace above the product has been evacuated, and is subsequently subjected to external pressure so as to be non-elastically stretched and made to lie wholly in contact with the enclosed product. When retorted (e.g. for sterilization) the package suffers no visible deformation of the container (12), despite the considerable volume shrinkage of the container which may occur. The loss of volume caused by this volume shrinkage is accommodated by a reduction in the concavity of the diaphragm (20) caused by a corresponding heat-induced shrinkage of the diaphragm material. The diaphragm continues to exhibit a pleasing, smooth or smoothly curving surface, and the retorted package has a consumer-acceptable appearance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.