Container with frangible weakened portion and manufacture thereof
AssigneeGr8 Engineering Limited
InventorPeter Reginald CLARKE
Life of this patent
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Abstract
A container, in the form of a container body or container closure, or a lid, having a frangible weakened portion formed in a layer of polyethylene terephthalate forming a wall of the container, the weakened portion comprising a groove cut into a first surface of the layer, a first portion of the layer surrounding the groove having a crystallinity of from 35 to 45%, and a second portion of the layer, which second portion is adjacent to the first portion on opposite sides of the groove and remote from the groove, the second portion having a crystallinity at least 5% less than the crystallinity in the first portion, wherein the layer has a thickness of from 200 to 700 μm and the groove has a depth of from 200 to 500 μm.
Claims36
A container comprising a part, in the form of a container body or container closure, or a lid, having a frangible weakened portion formed in a layer of polyethylene terephthalate forming a wall of the container, the frangible weakened portion comprising a groove cut into a first surface of the layer, a first portion of the layer surrounding the groove having a crystallinity of from 35 to 45%, and a second portion of the layer, which second portion is adjacent to the first portion on opposite sides of the groove and remote from the groove, the second portion having a crystallinity at least 5% less than the crystallinity in the first portion, wherein the layer has a thickness of from 200 to 700 μm and the groove has a depth of from 200 to 500 μm.
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A method of manufacturing a container comprising a part, in the form of a container body or container closure, or a lid, having a frangible weakened portion formed in a layer of polyethylene terephthalate forming a wall of the container, the method comprising the step of:
- (i) laser cutting a groove into a first surface of a layer of polyethylene terephthalate to form a frangible weakened portion, wherein the layer has a thickness of from 200 to 700 μm and the groove has a depth of from 200 to 500 μm, the laser cutting being controlled to provide a first portion of the layer surrounding the groove having a crystallinity of from 35 to 45%, and a second portion of the layer, which second portion is adjacent to the first portion on opposite sides of the groove and remote from the groove, the second portion having a crystallinity at least 5% less than the crystallinity in the first portion.
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36-38. (canceled)
40-45. (canceled)
Dependencies are inferred from the claim text.