Method for making polymeric web exhibiting a soft and silky tactile impression

Abstract

A polymeric web exhibiting a soft and silky tactile impression on at least one side thereof is disclosed. The silky feeling side of the web exhibits a pattern of discrete hair-like fibrils, each of the hair-like fibrils being a protruded extension of the web surface and having a side wall defining an open proximal portion and a closed distal portion. The hair-like fibrils exhibit a maximum lateral cross-sectional diameter of between 2 and 5 mils, and an aspect ratio from 1 to 3. Methods and apparatus for making the polymeric web utilize a three-dimensional forming structure having a plurality of protrusions being generally columnar forms having an average aspect ratio of at least about 1.

1 . A method for making a macroscopically expanded, three-dimensional, apertured polymeric web from a substantially planar polymeric precursor web, said method comprising the steps of:
 a. providing said precursor web; said precursor web having a thickness;   b. providing a forming structure having opposing first and second surfaces; said forming structure comprising a plurality of protrusions, said protrusions having an aspect ratio of at least 1; said protrusions having an amplitude measured from said first surface of said forming structure to a distal end of said protrusion, said protrusions being shaped such that an average dimension of a lateral cross-section at a particular amplitude is the same or greater than a similar average dimension of a lateral cross-section at any greater amplitude; said protrusions having a center-to-center spacing that is greater than twice the thickness of the precursor web; said forming structure comprising a multiplicity of forming structure apertures; said apertures placing said opposed surfaces of said forming structure in fluid communication with one another;   c. supporting said precursor web on said forming structure;   d. applying at least one high pressure fluid jet to said precursor web, said fluid jet(s) having sufficient mass and velocity to cause said precursor web to be formed into a macroscopically expanded, three-dimensional, apertured polymeric web comprising hair-like fibrils and apertures; said hair-like fibrils having a side wall defining an open proximal portion and a closed distal portion;   e. providing drying means for removing liquid from said apertured polymeric web; and   f. drying said macroscopically expanded, three-dimensional, apertured polymeric web.   
     
     
         2 . The method according to  claim 1  wherein said precursor web is thermoplastic, said web being selected from the group consisting of polyethylene, polypropylene, polyester, polystyrene, and copolymers and mixtures thereof. 
     
     
         3 . The method according to  claim 1  wherein said forming structure comprises a rotating surface of a stationary forming drum. 
     
     
         4 . The method of according to  claim 1 , wherein only a predetermined portion of said precursor web is caused to substantially conform to said forming structure. 
     
     
         5 . The method according to  claim 1 , wherein said drying means comprises one or more of radiant heat drying, convective drying, ultrasonic drying, and high velocity air drying. 
     
     
         6 . The method according to  claim 1 , wherein step (d) comprises two distinct steps:
 a. forming macroapertures by applying a first high pressure fluid jet to said precursor web; and   b. forming hair-like fibrils by applying a second high pressure fluid jet to said precursor web;   
     
     
         7 . The method according to  claim 1 , further comprising:
 g. annealing said macroscopically expanded, three-dimensional, apertured polymeric web on said forming structure.   
     
     
         8 . The method according to  claim 7 , wherein the drying and annealing steps are combined as one step. 
     
     
         9 . The method according to  claim 1 , wherein said forming structure comprises at least about 1550 protrusions per square centimeter. 
     
     
         10 . A method for making a macroscopically expanded, three-dimensional, apertured polymeric web from a substantially planar polymeric precursor web, said method comprising the steps of:
 a. providing said precursor web; said precursor web having a thickness;   b. providing a forming structure with opposed surfaces; said forming structure comprising a plurality of protrusions, said protrusions having an aspect ratio of at least 1; said protrusions comprising a protrusion sidewall, wherein said protrusion sidewall is generally straight; said protrusions having a center-to-center spacing that is greater than twice the thickness of the precursor web; said forming structure comprising a multiplicity of forming structure apertures; said apertures placing said opposed surfaces of said forming structure in fluid communication with one another;   c. supporting said precursor web on said forming structure;   d. applying at least one high pressure fluid jet to said precursor web, said fluid jet(s) having sufficient mass and velocity to cause said precursor web to be formed into a macroscopically expanded, three-dimensional, apertured polymeric web comprising hair-like fibrils and apertures; said hair-like fibrils having a side wall defining an open proximal portion and a closed distal portion;   e. providing drying means for removing liquid from said apertured polymeric web; and   f. drying said macroscopically expanded, three-dimensional, apertured polymeric web.   
     
     
         11 . The method according to  claim 10 , wherein said forming structure comprises at least about 1550 protrusions per square centimeter. 
     
     
         12 . The method of according to  claim 10 , wherein only a predetermined portion of said precursor web is caused to substantially conform to said forming structure. 
     
     
         13 . The method according to  claim 10 , wherein said drying means comprises one or more of radiant heat drying, convective drying, ultrasonic drying, and high velocity air drying. 
     
     
         14 . The method according to  claim 10 , wherein step (d) comprises two distinct steps:
 a. forming macroapertures by applying a first high pressure fluid jet to said precursor web; and   b. forming hair-like fibrils by applying a second high pressure fluid jet to said precursor web;   
     
     
         15 . The method according to  claim 10 , further comprising:
 g. annealing said macroscopically expanded, three-dimensional, apertured polymeric web on said forming structure.   
     
     
         16 . The method according to  claim 15 , wherein the drying and annealing steps are combined as one step. 
     
     
         17 . A method for making a macroscopically expanded, three-dimensional, apertured polymeric web from a substantially planar polymeric precursor web, said method comprising the steps of:
 a. providing said precursor web; said precursor web having a thickness;   b. providing a forming structure having opposing first and second surfaces; said forming structure comprising a plurality of protrusions, said protrusions having an aspect ratio of at least 1; said protrusions having a lateral cross-section that decreases in a direction towards a distal end of said protrusions; said protrusions having a center-to-center spacing that is greater than twice the thickness of the precursor web; said forming structure comprising a multiplicity of forming structure apertures; said apertures placing said opposed surfaces of said forming structure in fluid communication with one another;   c. supporting said precursor web on said forming structure;   d. applying at least one high pressure fluid jet to said precursor web, said fluid jet(s) having sufficient mass and velocity to cause said precursor web to be formed into a macroscopically expanded, three-dimensional, apertured polymeric web comprising hair-like fibrils and apertures; said hair-like fibrils having a side wall defining an open proximal portion and a closed distal portion;   e. providing drying means for removing liquid from said apertured polymeric web; and   f. drying said macroscopically expanded, three-dimensional, apertured polymeric web.