Process For Producing Absorbent Core Structures

Abstract

The present invention is method for forming a sandwich structure having a pattern of particulate material enveloped between a carrier material and a cover material. The method allows accurate forming of pre-determined pattern at high production speed. Such a method is particularly useful in the manufacture of disposable absorbent articles, such as baby diapers.

What is claimed is: 
     
         1 . A method for producing a sandwich structure comprising a pattern of particulate material, the method comprising the steps of:
 advancing a carrier material to a carrier support structure, the carrier support structure comprising a carrier support area, wherein the carrier material defines a support region and an unsupported region, wherein the carrier material is supported by the carrier support area in the support region;   forming an indentation in the unsupported region of the carrier material;   metering superabsorbent particles into the indentation of the carrier material;   advancing a cover material adjacent to the carrier material; and   bonding the cover material to the carrier material in the support region of the carrier material, wherein the superabsorbent particles are sandwiched between the carrier material and the cover material.   
     
     
         2 . The method of  claim 1 , further comprising the step of rotating the carrier support structure. 
     
     
         3 . The method of  claim 1 , wherein the carrier material has a CD-extensibility or a MD-extensibility of more than about 20%. 
     
     
         4 . The method of  claim 1 , wherein the cover material is a non-woven material. 
     
     
         5 . The method of  claim 1 , wherein the step of bonding the cover material to the carrier material in the support region of the carrier material further comprises the step of glue-bonding the cover material to the carrier material in the support region of the carrier material. 
     
     
         6 . The method of  claim 1 , wherein the carrier support area comprises a cylindrical surface. 
     
     
         7 . The method of  claim 1 , wherein the carrier support structure comprises vacuum air suction. 
     
     
         8 . The method of  claim 1 , wherein the indentation has a volume of more than 30 mm 3 . 
     
     
         9 . The method of  claim 1 , wherein the step of metering superabsorbent particles into the indentation of the carrier material further comprises:
 transferring superabsorbent particles from a bulk storage to a rotating transfer device, wherein the rotating transfer device comprises recesses;   retaining superabsorbent particles in the recesses with vacuum air; and   discharging superabsorbent particles from the recesses into the indentation of the carrier material.   
     
     
         10 . A method for producing a sandwich structure comprising a pattern of particulate material, the method comprising the steps of:
 advancing a carrier material to a carrier support structure, the carrier support structure comprising a carrier support area, wherein the carrier material defines support regions and unsupported regions, wherein the carrier material is supported by the carrier support area in the support regions;   deforming the carrier material to form indentations in unsupported regions of the carrier material;   transferring superabsorbent particles to recesses in a transfer device in a loading position;   rotating the recesses from the loading position to a discharging position;   transferring the superabsorbent particles from the recesses into the indentations of the carrier material at the discharging position;   advancing a cover material adjacent to the carrier material; and   bonding the cover material to the carrier material, wherein the superabsorbent particles are sandwiched between the carrier material and the cover material.   
     
     
         11 . The method of  claim 10 , wherein the step of rotating the recesses further comprises retaining superabsorbent particles in the recesses with vacuum air. 
     
     
         12 . The method of  claim 11 , wherein the step of transferring the superabsorbent particles from the recesses into the indentations further comprises expelling superabsorbent particles from the recesses with blow off air. 
     
     
         13 . The method of  claim 10 , further comprising the step of rotating the carrier support structure. 
     
     
         14 . The method of  claim 10 , wherein the step of bonding the cover material to the carrier material further comprises the step of glue-bonding the cover material to the carrier material in the support regions of the carrier material. 
     
     
         15 . The method of  claim 10 , wherein the carrier support structure comprises vacuum air suction. 
     
     
         16 . A method for producing a sandwich structure comprising a pattern of particulate material, the method comprising the steps of:
 advancing a carrier material to a carrier support structure, the carrier support structure comprising a carrier support area, wherein the carrier material defines support regions and unsupported regions, wherein the carrier material is supported by the carrier support area in the support regions;   deforming the carrier material to form indentations in unsupported regions of the carrier material;   metering superabsorbent particles into the indentations of the carrier material;   advancing a cover material adjacent to the carrier material; and   bonding the cover material to the carrier material between the indentations of the carrier material, wherein the superabsorbent particles are sandwiched between the carrier material and the cover material.   
     
     
         17 . The method of  claim 16 , wherein the step of metering superabsorbent particles into the indentations of the carrier material further comprises:
 transferring superabsorbent particles from a bulk storage to a transfer device, wherein the transfer device comprises recesses;   transporting superabsorbent particles in the recesses; and   transferring superabsorbent particles from the recesses into the indentations of the carrier material.   
     
     
         18 . The method of  claim 17 , wherein the step of transporting superabsorbent particles in the recesses further comprises retaining superabsorbent particles in the recesses with vacuum air. 
     
     
         19 . The method of  claim 18 , wherein the step of transferring the superabsorbent particles from the recesses into the indentations further comprises expelling superabsorbent particles from the recesses with blow off air. 
     
     
         20 . The method of  claim 16 , wherein the step of bonding the cover material to the carrier material further comprises the step of glue-bonding the cover material to the carrier material. 
     
     
         21 . The method of  claim 16 , further comprising the step of rotating the carrier support structure. 
     
     
         22 . The method of  claim 16 , wherein the carrier support structure comprises vacuum air suction. 
     
     
         23 . An absorbent sandwich structure comprising:
 a carrier layer comprising indentations;   clusters of superabsorbent particles positioned in the indentations of the carrier material; and   a cover material bonded to the carrier material between the indentations of the carrier material and defining channel regions between neighboring clusters.   
     
     
         24 . The absorbent sandwich structure of  claim 23 , wherein the indentations are deformed out of a flat plane. 
     
     
         25 . The absorbent sandwich structure of  claim 24 , wherein:
 a first plurality of the clusters of the superabsorbent particles are arranged in a first row;   a second plurality of the clusters of the superabsorbent particles are arranged in a second row separate from the first row; and   wherein the cover material is bonded to the carrier material between the first row and the second row.   
     
     
         26 . The absorbent sandwich structure of  claim 25 , wherein the cover material is not bonded to the carrier material in channel regions between the neighboring clusters in the first row, and wherein the cover material is not bonded to the carrier material in channel regions between the neighboring clusters in the second row. 
     
     
         27 . The absorbent sandwich structure of  claim 26 , further comprising adhesive that permanently bonds the cover material to the carrier material between the first row and the second row. 
     
     
         28 . The absorbent sandwich structure of  claim 27 , wherein the first row is parallel to the second row. 
     
     
         29 . The absorbent sandwich structure of  claim 28 , wherein the first row is parallel to a characteristic axis that is angularly offset from a longitudinal axis of the absorbent sandwich structure. 
     
     
         30 . The absorbent sandwich structure of  claim 23 , wherein the clusters define circular shapes.