Film material exhibiting textile properties and method and apparatus for its manufacture

Abstract

A film material formed of thermoplastic polymer material is processed so as to have linearly extending regions (A) linked together by linearly extending webs (B), regions (A) and webs (B) each being oriented, the dominant direction of orientation in regions (A) forming an angle (V) to the direction on which (A) extends and webs (B) comprising arrays of linear furrows of thinner material or splits forming angles (U) higher than (V) to the direction in which (A) extends. The method of producing the new film involves passing an orientated film through a pair of intermeshing grooved rollers to cold-stretch the film in a direction at an angle to the predominant original orientation, at least one of the grooved rollers having crests with sharp edges to form the division between regions A and webs B and to stretch the material to form webs B while stretching the material less or not at all to form regions A. Preferably at least one of the grooved rollers has crests with a waved surface shape.

We claim: 
     
         1 . A product comprising:
 a film or an assembly of films comprising:
 an array of parallel band-shaped, linearly extending regions (A) and 
 distinct linearly extending webs (B) integrally connecting the regions (A), 
 where each web (B) along its linear extension is thinner than adjacent portions of the regions (A), and 
   where the regions (A) and the webs (B) are oriented having at each location a dominating direction of orientation,   where each of the dominating directions of orientation of the regions (A) forms an angle (v) with a direction in which the regions (A) extend,   where the angle (v) has a value greater than 0° and less than or equal to 80°,   where the regions (A) are waved and the waves extend along a width of the regions (A),   where the webs (B) are contracted transversely of their main direction of orientation to stabilize the waves in the regions (A), and   where each film comprises a thermoplastic polymer material.   
     
     
         2 . The product according to  claim 1 , wherein the webs (b) have a width that is less than the width of the waved regions (A). 
     
     
         3 . The product according to  claim 1 , wherein the linear extending regions (A) include interrupting lines forming regions of interruptions (D) comprising webs thinner than the regions (A) substantially similar in thickness to the webs (B) so that no distinct border exists between the web regions (B) and the regions of interruption (D), whereby each interrupted linear region (A) including its thinner regions of interruptions (D) is waved, the regions of interruption (D) comprise crests of the webs. 
     
     
         4 . The product according to  claim 1 , wherein the dominating direction of orientation within each region (A) varies in a sequences not greater than 10 mm in length. 
     
     
         5 . The product according to  claim 1 , wherein the product is an assembly of films comprising a crosslaminate, whereby the dominating directions of orientation of each film in the assembly and at each location of the laminate cross each other, the assembled films being joined in spots, lines or a combination thereof by bonding or blocking or both. 
     
     
         6 . The product according to  claim 5 , wherein the regions (A) in different films of the crosslaminate cover each other along their full lengths, and the webs (B) cover each other along their full lengths. 
     
     
         7 . The product according to  claim 6 , wherein the bonding or blocking is limited so that a major portion of each of the webs (B) are unbonded and unblocked. 
     
     
         8 . The product according to  claim 5 , wherein the bonding or blocking is established through surface layers selected to aid the laminating to form the crosslaminate. 
     
     
         9 . The product according to  claim 5 , wherein in the regions (A), an angle between dominating directions of orientation of any two laminated films is smaller than a sum of angles which each of these directions form with the direction in which the regions (A) extends. 
     
     
         10 . The product according to  claim 1 , wherein at least 50% of the film or each of the films in the assembly comprise high density polyethylene (HDPE) or isotactic or syndiotactic polypropylene (PP) or low. 
     
     
         11 . The product according to  claim 1 , wherein a gauge of the film or of each the films in the assembly is less than or equal to 15 grams per square meter (g/m 2 ). 
     
     
         12 . The product according to  claim 1 , wherein an average gauge of each web (B) is less than or equal to 70% of an average gauge of the two adjacent regions (A). 
     
     
         13 . The product according to  claim 12 , wherein in all directions the elongation at break is no less than 100% and the ultimate tensile strength no less than 10 MPa, referring to tensile testing of 2.5 cm wide ribbons at a velocity corresponding to 500% elongation per minute. 
     
     
         14 . The product according to  claim 1 , wherein a width of each region (A) is less than or equal to 2 mm. 
     
     
         15 . The product according to  claim 14 , wherein a division of an array of regions (A) is less than or equal to 4 mm. 
     
     
         16 . The product according to  claim 1 , wherein the product is continuous and the regions (A) extend substantially parallel to the continuous extension of the product.