Plastic bag and closed plastic bag with laser-formed venting perforations
US4743123A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 11, 1986 |
| Grant date | May 10, 1988 |
| Priority date | — |
| Expiry date | Jul 11, 2006 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB26F1/31
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A plastic bag of polyolefin material such as polyethylene, for packaging materials, comprising particles of less than 50 .mu.m, and a closed bag containing such materials and a foil material for such a bag. The foil wall of the bag is provided with venting apertures with smooth edges, obtained by laser radiation, having a maximum size of 50-100 .mu.m; the distance between the venting perforations is such that the tensile strength of the foil is substantially the same as the tensile strength of the similar non-perforated foil. In a low density polyethylene foil of a thickness of 130-190 .mu.m distance between the perforations of 80 .mu.m is more than 20 mm, in a linear low density polyethylene foil of about 50-110 .mu.m the perforation distance is at least 5 mm. The bag may consist of two perforated foil layers, the perforations being staggered with respect to each other.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.