Air cellular cushioning article of enhanced strength per unit weight of film, and process for making same

摘要

The cellular cushioning article comprises a thermoformed film bonded to a second film, with the thermoformed film having thermoformed regions separated by a land area. The thermoformed film has a combination of (i) a layer containing a high melt point polymer and (ii) thermoformed regions exhibit a high average maximum birefringence. The high birefringence corresponds with high stress on the polymer chains. The combination results in cells of substantially increased burst strength. The cellular cushioning article can provide higher burst strength per mil of film thickness, or can be produced using less plastic than prior art cellular cushioning articles, while maintaining the same or comparable burst strength. Also disclosed is a process for making the cellular cushioning article.

主权项

1. A cellular cushioning article comprising a multilayer first film and a second film, the first film having a thermoformed portion comprising a plurality of discrete thermoformed regions separated by an unformed land area, with each discrete thermoformed region providing a discrete raised embossment, with the second film having a bonded portion and an unbonded portion, with the unbonded portion comprising a plurality of discrete unbonded regions, with each discrete unbonded region including at least a portion juxtaposed opposite a base of each of the discrete thermoformed regions of the first film, with the bonded portion of the second film being bonded to at least a portion of the land area of the first film, with the plurality of discrete thermoformed regions of the first film and a plurality of discrete unbonded regions of the second film together making up a plurality of discrete cells, with each cell surrounding a discrete volume of fluid entrapped between the first film and the second film, with the first film having a bonding layer comprising polyolefin and a high melt point layer comprising polyamide, and the cellular cushioning article has a combination of an average thickness of the land area of the first film, and an average maximum birefringence of the thermoformed regions of the first film, selected from the group consisting of:
(A) average land area thickness of from 2.01 mils to 3 mils, and an average maximum birefringence of at least 6×10−3; (B) average land area thickness of from 1.41 mils to 2 mils and an average maximum birefringence of at least 16×10−3; (C) average land area thickness of from 1.01 mils to 1.40 mils and an average maximum birefringence of at least 17×10−3; (D) average land area thickness of from 0.76 mil to 1.0 mil and an average maximum birefringence of at least 17×10−3; (E) average land area thickness of from 0.45 rail to 0.75 rail and an average maximum birefringence of at least 17×10−3.