Continuous method for elasticizing discrete articles cut from a moving web in a direction perpendicular to web travel

Claim 1

. A continuous method for elasticizing substantially inelastic articles by securing elastically contractible elements to a moving, interconnected web of said articles, said elastically contractible elements causing the discrete articles cut from said web to shirr in a direction substantially perpendicular to the direction of web travel, said method comprising the steps of: (a) subjecting a web of elastomeric material capable of exhibiting dimensionally heat stable and dimensionally heat unstable states to lateral stretching while said web is at an elevated temperature which is less than its crystalline melting temperature; (b) allowing said elastomeric web to cool to ambient temperature while in a laterally stretched condition to establish a heat unstable state in the material comprising said web; (c) feeding said web of elastomeric heat unstable material in a direction substantially parallel to said moving web of interconnected articles; (d) severing discrete segments of said elastomeric heat unstable material from said elastomeric web in a direction substantially perpendicular to the direction of web travel, whereby each of said discrete segments of elastomeric material has its length oriented parallel to the direction of said lateral stretching and its width extending in a direction substantially parallel to the direction of web travel; (e) transferring said discrete, severed segments of elastomeric material in a substantially untensioned condition and while their lengths are oriented substantially perpendicular to the direction of web travel to said moving web of interconnected articles at isolated, predetermined locations along the length of said web; _ (f) securing said discrete segments of substantially untensioned, heat unstable elastomeric material to said web of interconnected articles at predetermined spaced locations along the length of said segments, as measured in a direction substantially perpendicular to the direction of web travel; (g) severing each of the interconnected articles from one another, thereby forming a multiplicity of discrete articles, each having at least one segment of substantially untensioned elastomeric material in a heat unstable condition secured thereto; and (h) heating said discrete articles to an elevated temperature which is less than the crystalline melting temperature of said heat unstable segments of substantially untensioned elastomeric material, thereby causing said elastomeric material to contract in a direction substantially parallel to its overall length, to become heat stable and elastic, and to shirr said articles in a direction substantially perpendicular to said direction of web travel.

Claim 4

A method according to either one of claims 1 and 2, wherein said web of interconnected articles is subjected to a folding operation aligned substantially parallel to the direction of web travel prior to severing said interconnected articles from one another, said discrete articles thereafter being subjected to said heating while they are in said folded configuration to provide non-uniform shirring in the resultant elasticized articles.

Claim 6

A method according to any one of claims 1-4, wherein the step of transferring discrete severed segments of elastomeric material comprises feeding said web of heat unstable, substantially untensioned elastomeric material in a direction parallel to the direction of travel of said web of interconnected articles at a velocity less than that of said web of interconnected articles, and thereafter severing discrete segments from said web of elastomeric material.

Claim 7

A method according to any one of claims 1-5, wherein said discrete segments of substantially untensioned, heat unstable elastomeric material are secured to said web of interconnected articles by ultrasonic bonding.

Claim 8

A method according to any one of claims 1-6, wherein said elastomeric material comprises a blend of ethylene propylene rubber and ethylene vinyl acetate.

Claim 9

A method according to any one of claims 1-7, wherein said discrete, severed segments of heat unstable elastomeric material are indirectly transferred to said moving web of interconnected articles.

Claim 11

A method according to any one of claims 1-9, wherein said elastomeric web is allowed to cool to ambient temperature after lateral stretching without restraint.

Claim 12

A method according to any one of claims 1-10, wherein the step of severing the interconnected articles from said web takes place after the heating step that causes said elastomeric material to contract in a direction substantially parallel to its overall length.

Claim 13

A method according to any one of claims 1-11, wherein the substantially inelastic articles comprise disposable diapers comprising a backsheet, an absorbent element and a topsheet, wherein an elastically contractible element is secured to at least one waistband portion of each said diaper.