Structuring fabric with sublayer beads and method of producing the same

Abstract

A structuring fabric for use in a machine to produce a structured fiber web, such as a structured tissue fiber web, has a machine direction, a cross machine direction, and a thickness direction. The structuring fabric includes a woven base fabric with a web facing side and a machine side. A plurality of structuring beads of polymeric material are formed on the web facing side of the woven base fabric, the structuring beads being suitable to provide a visible structure to the fiber web that is produced on the structuring fabric. The structuring beads rest on an upper foundation surface of corresponding sublayer beads of polymeric material. The sublayer beads thereby provide a foundation for the structuring beads. There is also described a production method for producing such a structuring fabric.

1 . A structuring fabric for use in a machine for producing a structured fiber web, the structuring fabric comprising:
 a woven base fabric having a web facing side and a machine side, and said woven base fabric defining a machine direction, a cross machine direction, and a thickness direction;   a plurality of sublayer beads of polymeric material disposed in said woven base fabric;   a plurality of structuring beads of polymeric material disposed on the web facing side of said woven base fabric, said structuring beads being configured to provide a visible structure to the fiber web produced on the structuring fabric; and   said structuring beads resting on an upper foundation surface of respectively corresponding said sublayer beads, with said sublayer beads providing a foundation for said structuring beads.   
     
     
         2 . The structuring fabric according to  claim 1 , wherein a shape of the upper foundation surface of said sublayer beads substantially corresponds to a shape of a lower surface of the corresponding said structuring beads resting thereon. 
     
     
         3 . The structuring fabric according to  claim 1 , wherein the upper foundation surface of said sublayer beads is substantially flat. 
     
     
         4 . The structuring fabric according to  claim 1 , wherein, in the thickness direction of the structuring fabric, said sublayer beads are disposed substantially within a volume of said woven base fabric. 
     
     
         5 . The structuring fabric according to  claim 1 , wherein said woven base fabric comprises an upper layer defining the web facing side of said woven base fabric, said upper layer being formed from upper cross-machine direction yarns that are interwoven with upper machine direction yarns, and said sublayer beads extending so deeply into said woven base fabric to create a form-fit connection with at least some of said upper cross-machine direction yarns at deepest points thereof. 
     
     
         6 . The structuring fabric according to  claim 1 , wherein said structuring beads have a substantially rectangular cross-sectional shape. 
     
     
         7 . The structuring fabric according to  claim 6 , wherein said structuring beads are substantially square in cross-section. 
     
     
         8 . The structuring fabric according to  claim 1 , wherein said structuring beads form continuous lines on a web-facing surface of said woven fabric. 
     
     
         9 . The structuring fabric according to  claim 8 , wherein the continuous lines substantially extend in the machine direction of the structuring fabric. 
     
     
         10 . The structuring fabric according to  claim 1 , wherein said structuring beads form straight lines on a web-facing surface of said woven fabric or said structuring beads have a wavy configuration. 
     
     
         11 . The structuring fabric according to  claim 1 , wherein a polymeric material of said structuring beads is the same as a polymeric material of said sublayer beads. 
     
     
         12 . The structuring fabric according to  claim 1 , wherein at least one of a polymeric material of said structuring beads or a polymeric material of said sublayer beads is a material selected from the group consisting of silicone and polyurethane. 
     
     
         13 . The structuring fabric according to  claim 1 , wherein at least one of a polymeric material of said structuring beads or a polymeric material of said sublayer beads is an acrylic material. 
     
     
         14 . The structuring fabric according to  claim 13 , wherein the acrylic material is a UV-curable acrylic material. 
     
     
         15 . The structuring fabric according to  claim 13 , wherein the acrylic material comprises at least one component selected from the group consisting of:
 N,N-dimethylacrylamide;   2-propenoic acid, 2-hydroxyethyl ester, polymer with 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane;   isobornyl acrylate;   2-(2-ethoxyethoxy)ethyl acrylate;   diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide;   [3-(2,3-epoxypropoxy)propyl]trimethoxysilane;   acrylic acid;   2-hydroxyethyl acrylate; and   wherein none of said components contributes more than 50 wt-% to the composition of the acrylic material.   
     
     
         16 . A method of producing a structuring fabric for use in a machine for producing a structured fiber web, the method comprising:
 providing a woven base fabric;   extruding a sublayer bead of polymeric material through a first extrusion nozzle onto a web facing surface of the woven base fabric, the sublayer bead having an upper foundation surface; and   extruding a structuring bead of polymeric material through a second extrusion nozzle onto a top of the upper foundation surface of the sublayer bead.   
     
     
         17 . The production method according to  claim 16 , wherein the first extrusion nozzle and the second extrusion nozzle are integrally formed in one extrusion die. 
     
     
         18 . The production method according to  claim 16 , which comprises, during an extrusion process, aligning a first surface of an extrusion die in which the first extrusion nozzle is formed substantially parallel to a web facing surface of the woven base fabric, and aligning a second surface of the extrusion die in which the second extrusion nozzle is formed inclined with respect to the web facing surface of the woven fabric. 
     
     
         19 . The production method according to  claim 18 , wherein a spacing distance of the first extrusion nozzle to the web facing surface of the woven fabric is greater than a spacing distance of the second extrusion nozzle to the web facing surface of the woven fabric during the extrusion process. 
     
     
         20 . The production method according to  claim 16 , which comprises extruding the structuring bead at a time when the sublayer bead has not yet been cured. 
     
     
         21 . The production method according to  claim 16 , wherein the first nozzle is substantially rectangular-shaped and the second nozzle is substantially star-shaped. 
     
     
         22 . The production method according to  claim 21 , wherein a width of the first, substantially rectangular-shaped nozzle is substantially equal to a smallest width of the second, substantially star-shaped nozzle, and/or a length of the first, substantially rectangular-shaped nozzle is substantially half a length of the second, substantially star-shaped nozzle.