Method and apparatus for pin-hole prevention in zone laminates
AssigneeClopay Plastic Products Company, Inc.
InventorThomas G. Mushaben
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Abstract
The method and apparatus of the present invention prevents the formation of pin-holes during stretching of strip laminates in the cross-machine direction (CD). Pin-holes are prevented by creating slack areas (10a) along the length of the laminate (10) where the edges of the non-woven strips (14) meet with the polymer film (12), pressing the slack areas (10a) into the interdigital stretching rollers (26) without stretching the slack areas (10a), and stretching the remainder of the laminate (10) in a typical manner. The slack areas (10a) are formed prior to interdigitation by, for example, formation of a furrow, a fold or a corrugation.
Claims13
A method of forming a polymeric film having differing degrees of microporosity including the steps of:
- providing a film of a microporous formable polymer composition;
- and
- interdigitally stretching the film throughout its depth along a plurality of lines to form a microporous area in the film adjacent a film boundary area while controlling said film in a substantially unstretched condition in said boundary area adjacent said microporous area to reduce pinhole formation in the film.
Dependencies are inferred from the claim text.