Plastic closure
US5839592A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 9, 1995 |
| Grant date | Nov 24, 1998 |
| Priority date | — |
| Expiry date | Jun 9, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB32B2435/00
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A closure is formed from a laminate or composite. The laminate is sufficiently flexible to permit it to assume the surface configuration of the rim of a closure without the need for a gasket. The laminate may include an upper layer which is rigid and a lower layer which is softer and has a lower softening temperature than the upper layer. An optional intermediate oxygen-impermeable layer such as ethylene vinyl alcohol can be included between the upper and lower layers. Preferably, the upper layer is a rigid material such as polyethylene terephthalate or polyvinyl chloride and the lower layer is a soft material such as linear low-density polyethylene. The upper layer provides the necessary strength, while the lower layer provides a tight seal on the rim of the container. The intermediate or bottom layer can also include an oxygen indicator which changes color upon exposure to oxygen.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.