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US 4,379,774 AGranted
Process for the production of biaxially stretched and embossed film composed of vinyl chloride polymers
AssigneeHoechst Aktiengesellschaft
InventorsHeinz-Erhardt Andersen, Jaek J. Brebels, Klaus Matschke, Franz Scheier
Life of this patent
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Abstract
A process is described for the production of biaxially stretched and embossed polyvinyl chloride film, in which a polyvinyl chloride film is first stretched biaxially at specific stretching ratios and, immediately after being stretched, is embossed under specific conditions. The film produced by this process is employed with particular advantage as base film for adhesive tapes.
Claims5
A process for the production of biaxially stretched and embossed polyvinyl chloride film which comprises
- (a) biaxially stretching a polyvinyl chloride film at a stretching temperature of 90.degree. to 160.degree. C. at a transverse stretching ratio of 1.2:1 to 2.2:1 and a longitudinal stretching ratio of 1.7:1 to 2.5:1, the product of the transverse and longitudinal stretching ratios not exceeding 3.8:1, and
- (b) immediately after stretching, before the polyvinyl chloride film stretched according to step (a) has cooled appreciably from the stretching temperature range of 90.degree. to 160.degree. C. utilized in step (a), embossing the film by means of an embossing unit comprising an embossing roller back-up cylinder, the temperature of the film as it comes on to the embossing roller being substantially within said stretching temperature range and the embossing roller having a temperature of -10.degree. to +60.degree. C. and the embossing pattern of the embossing roller being embossed into the film to a depth of embossing of 0.02 to 0.25 mm.
Dependencies are inferred from the claim text.