Manufacture of plastic containers
CA 1099065 A · Owner: Du Pont Canada Inc. · Inventors: Hetherington, Brian L.; Kelly, Peter Y.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to an improvement in a method for the thermoforming of containers from thermoplastic materials in which method the rim of the container is formed as an integral part of the pre-form from which the container is thermoformed. The pre-form is obtained by introducing thermoplastic material into a closed space and then mechanically compressing the material. The improvement of the present invention relates to improved uniformity of flow of the thermoplastic material into the closed space the use, of a closed space defined by surfaces having a surface roughness in the range 50-125 µm rms and to a modified sequence of steps for forming the pre-form in which the …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted April 14, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 14, 1998.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.