Process and product thereof for stretching a non-woven web of an orientable polymeric fiber
AssigneeBiax-Fiberfilm Corporation
InventorEckhard C. A. Schwarz
Life of this patent
Estimating the term…
Abstract
A non-woven web of synthetic fibers is selectively stretched in incremental portions in a first and second station wherein the first and second station are provided with sets of rolls having grooves parallel and perpendicular, respectively, to the axis of each set of rolls to form a bi-axially stretched web. One groove pattern of the rolls is generally a sinosoidal wave with distances between grooves being less than 1.0 millimeters times the web basis weight in grams per square meter.
Claims12
A process for longitudinally stretching incremental portions of a non-woven web of thermoplastic orientable polymeric fibers to thereby improve the strength of the web which comprises:
- (a) introducing said web into a nip of interdigitating rollers having grooves substantially parallel to the axis of said rollers, the distance between grooves being less than one millimeter times the web basis weight in grams per square meter;
- (b) controlling the velocity of introduction of said web into said nip to assume and maintain the velocity substantially identical to the surface velocity of said rollers to prevent slipping of said web and thereby longitudinally and uniformly stretch said web between bonding points of each individual fiber by a deflection of said web into the shape of said grooves;
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- (c) collecting the thus stretched web.
The process for laterally stretching incremental portions of a non-woven web of thermoplastic orientable polymeric fibers to thereby improve the strength of the web which comprises:
- (a) introducing said web into a nip of interdigitating rollers having grooves substantially perpendicular to the axis of said rollers, the distance between grooves being less than one millimeter times the web basis weight in grams per square meter;
- (b) controlling the velocity of introduction of said web into the said nip to assume and maintain the velocity substantially identical to the surface velocity of said rollers to prevent narrowing of said web prior to introduction into said nip and thereby to laterally and uniformly stretch said web between bonding points of each individual fiber by a deflection of said web into the shape of said grooves;
- (c) withdrawing said web from said rollers at a velocity substantially corresponding to the velocity of introduction;
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- (d) collecting the thus stretched web.
A process for biaxially stretching a non-woven web of thermoplastic orientable polymeric fibers to thereby improve the strength of the web which comprises:
- (a) introducing said web into a nip of interdigitating rollers having grooves substantially parallel to the axis of said rollers, the distance between grooves being less than one millimeter times the web basis weight in grams per square meter;
- (b) controlling the velocity of introduction of said web into said nip to assume and maintain the velocity substantially identical to the surface velocity of said rollers to prevent slipping of said web and thereby longitudinally and uniformly stretch said web between bonding points of each individual fiber by a deflection of said web into the shape of said grooves;
- (c) withdrawing said web from said rollers at a velocity greater than the rotational velocity of said rollers;
- (d) introducing said web into a nip of interdigitating rollers having grooves substantially perpendicular to the axis of said rollers, the distance between grooves being less than one millimeter times the web basis weight in grams per square meter;
- (e) controlling the velocity of introduction of said web into the said nip to assume and maintain the velocity substantially identical to the surface velocity of said rollers to prevent narrowing of said web prior to introduction into said nip and thereby to laterally and uniformly stretch said web between bonding points of each individual fiber by a deflection of said web into the shape of said grooves;
- (f) withdrawing said web from said rollers at a velocity substantially corresponding to the velocity of introduction;
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- (g) collecting a biaxially stretched web.
Dependencies are inferred from the claim text.