Method and apparatus for pin-hole prevention in zone laminates
AssigneeClopay Plastic Products Company, Inc.
InventorThomas G. Mushaben
Life of this patent
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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.
Claims30
A laminate of non-woven and polymeric film comprising:
- a polymeric film;
- and
- at least one non-woven strip having opposite edges, the strip laminated to the film to form a laminated area along the length of the film and unlaminated film areas along the opposite edges, said opposite strip edges each defining a boundary area between the laminated area and the unlaminated area;
- wherein the boundary areas are unstretched and the laminated area and the unlaminated area are interdigitally stretched.
A microporous laminate sheet having improved breatheability and liquid barrier properties comprising:
- a polymer film barrier layer;
- at least one non-woven layer having opposite edges laminated to the polymer barrier layer forming a laminated area and a nonlaminated area, having boundary areas at the edges of the non-woven;
- wherein the film and non-woven laminate areas and the nonlaminated polymer film laminate area are interdigitally stretched in the cross-machine direction and the boundary areas are unstretched in the cross-machine direction.
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 it depth along a plurality of lines while controlling said film in a substantially unstretched condition adjacent said lines to reduce pinhole formation in the film.
A device for preventing pin-holing during the creation of micropores in a laminate comprising:
- a first interdigital roller;
- a second interdigital roller, intersecting the first interdigitating roller, the intersection of said first and second interdigital roller serving to interdigitally stretch a laminate of non-woven and microporous formable film across the width of the laminate except in the slack areas of the laminate to form micropores;
- and
- at least one disc for contacting a slack area in the laminate and pressing the slack area into the first interdigital roller without stretching the slack area.
A device for preventing pin-holing during the creation of micropores in a laminate comprising:
- a first interdigital roller;
- a second interdigital roller, intersecting the first interdigitating roller, the intersection of said first and second interdigital roller serving to interdigitally stretch a laminate stretch a laminate of non-woven and microporous formable film across the width of the laminate except in slack areas of the laminate;
- and
- means for creating at least one slack area along the length of a laminate.
Dependencies are inferred from the claim text.