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US 4,488,918 AGranted
Non-slip plastic film
AssigneeOy Wiik & Hoglund AB
InventorJarl-Erik Jofs
Life of this patent
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Abstract
This invention discloses a plastic film having a non-slip surface comprising spaced random patterns of rigid peaks and ridges formed by a second thermo-plastic layer coextruded with and bonded to the plastic film and rupturing the second layer during expansion.
Claims19
A method of making a film of plastic material with a non-slip surface having a coefficient of friction of at least 0.45 comprising the steps of:
- extruding a first layer of plastic film having a predetermined capability to resist tearing and rupturing upon stretching;
- and
- simultaneously coextruding therewith a second layer of plastic material having a predetermined lesser capability to resist rupture on stretching than said first layer;
- and
- coextruding said second layer so that said second layer is bonded, at least at a multiplicity of spots, to said first layer;
- expanding and coextruded layers after extrusion so as to cause the rupture of said second layer into a random pattern of high, hard, sharp peaks and ridges;
- said second layer being formed of a high elasticity thermoplastic material having a melt flow index in the plastic-elastic state at least as low as 1.0, and having a high density in the range of 0.920 to 0.960.
4 more elements
Dependencies are inferred from the claim text.