Multi-layer plastic sheet used to make packaging in form of tear-open bags with predefined lines of weakness, contains polyolefin layers with and without substance absorbing laser energy

摘要

The sheet comprises polyolefin layers (3, 4, 5). At least one of these (3) contains a laser-absorbent substance. At least one other layer (4) does not contain this substance. A line of weakness (1) is introduced into the layer containing the laser-absorbent substance, using a CO 2laser beam (2). The polyolefin layers (3, 4) lie immediately adjacent to each other. Optionally the substance-containing polyolefin layer lies between polyolefin layers (4, 5) which do not contain the substance. The layers (3, 4, 5) are made of polyethylene. An independent claim IS INCLUDED FOR the method of manufacturing the tear-open bag.