Method for incrementally stretching a zero strain stretch laminate web to impart elasticity thereto

An improved method for incrementally stretching a zero strain stretch laminate web to impart elasticity thereto in the direction of stretching, at least up to the point of initial stretching, said method comprising the steps of:

• feeding a zero strain stretch laminate web comprising a substantially untensioned first elastomeric ply substantially continuously secured to a substantially untensioned second ply comprising a continuous web which is elongatable, but which exhibits less elastic recovery than said first ply, between a pair of opposed pressure applicators having three-dimensional surfaces which at least to a degree are complementary to one another;
• (b) restraining the opposed peripheral edge portions of said second elongatable ply adjacent the portion of said zero strain stretch laminate web to be incrementally stretched to substantially prevent slippage or contraction thereof in a direction substantially parallel to the direction of stretching;
• and
• (c) subjecting the portions of said zero strain stretch laminate web located between said opposed points of restraint to incremental stretching, while said second elongatable ply is subject to the restraint applied in step (b), by causing said opposed three-dimensional surfaces of said pressure applicators to mesh with one another at least to a degree, whereby said second elongatable ply is permanently elongated by said incremental stretching so that said laminate web is elastically extensible in the direction of initial stretching, at least up to the point of initial stretching, and the width of said laminate web measured in said direction of stretching is substantially the same as before said initial stretching is applied once the initial incremental stretching forces are removed from said zero strain stretch laminate web.

An improved method for incrementally stretching a continuously moving zero strain stretch laminate web to impart elasticity thereto in the direction of stretching, at least up to the point of initial stretching, said method comprising the steps of:

• (a) continuously feeding a zero strain stretch laminate web comprising a substantially untensioned first elastomeric ply intermittently secured to a substantially untensioned second ply comprising a continuous web which is elongatable, but which exhibits less elastic recovery than said first ply, between a pair of opposed pressure applicators comprising corrugated rolls having an axis of rotation perpendicular to the direction of web travel, said corrugated rolls having three-dimensional surfaces comprising corrugations which at least to a degree are complementary to one another;
• (b) restraining the opposed peripheral edge portions of said first elastomeric ply and said second elongatable ply adjacent the portion of said continuously moving zero strain stretch laminate web to be incrementally stretched to substantially prevent slippage or contraction thereof in a direction substantially parallel to the direction of stretching;
• and
• (c) subjecting the portions of said continuously moving zero strain stretch laminate web located between said opposed points of restraint to incremental stretching, while said first elastomeric ply and said second elongatable ply are subject to the restraint applied in step (b), by causing said opposed three-dimensional surfaces comprising said corrugations on said corrugated rolls to mesh with one another at least to a degree, while said continuously moving zero strain stretch laminate web passes therebetween, whereby said second elongatable ply is permanently elongated by said incremental stretching so that said laminate web is elastically extensible in the direction of initial stretching, at least up to the point of initial stretching, and the width of said laminate web measured in said direction of stretching is substantially the same as before said initial stretching is applied once the initial incremental stretching forces are removed from said zero strain stretch laminate web.

An improved method for incrementally stretching a continuously moving zero strain stretch laminate web to impart elasticity thereto in the direction of stretching, at least up to the point of initial stretching, said method comprising the steps of:

• (a) continuously feeding a zero strain stretch laminate web comprising a substantially untensioned first elastomeric ply substantially continuously secured to a substantially untensioned second ply comprising a continuous wet which is elongatable, but which exhibits less elastic recovery than said first ply, between a pair of opposed pressure applicators comprising corrugated rolls having an axis of rotation perpendicular to the direction of web travel, said corrugated rolls having three-dimensional surfaces comprising corrugations which at least to a degree are complementary to one another;
• (b) restraining the opposed peripheral edge portions of said first elastomeric ply and said second elongatable ply adjacent the portion of said continuously moving zero strain stretch laminate web to be incrementally stretched to substantially prevent slippage or contraction thereof in a direction substantially parallel to the direction of stretching;
• and
• (c) subjecting the portions of said continuously moving zero strain stretch laminate web located between said opposed points of restraint to incremental stretching, while said first elastomeric ply and said second elongatable ply are subject to the restraint applied in step (b), by causing said opposed three-dimensional surfaces comprising said corrugations on said corrugated rolls to mesh with one another at least to a degree, while said continuously moving zero strain stretch laminate web passes therebetween, whereby said second elongatable ply is permanently elongated by said incremental stretching so that said laminate web is elastically extensible in the direction of initial stretching, at least up to the point of initial stretching, and the width of said laminate web measured in said direction of stretching is substantially the same as before said initial stretching is applied once the initial incremental stretching forces are removed from said zero strain stretch laminate web.