Absorbent articles, method and apparatus for preparing same

Abstract

An apparatus and a method for preparing an absorbent article is disclosed. The apparatus has at least two forming surfaces which differ in terms of air permeability to allow the selective placement of fibrous material. The forming surface comprises a perforated forming screen. The forming screen has multiple zones with different amounts of open area through which air may pass. Particles carried in the air which flows through the open area are deposited on different zones of the forming screen resulting in different basis weights corresponding to the different air permeabilities. The apparatus and method thus provide an article having optimal zoned absorbency in a cost-effective manner.

1 - 37 . (cancelled)  
     
     
         38 . A method for preparing an absorbent article, comprising the steps of: 
 (a) providing a forming surface having a first predetermined zone with a first air permeability and a second predetermined zone with a second air permeability, and said first air permeability being different from said second air permeability;    (b) placing particles into an airflow;    (c) transporting the particles in the airflow through a forming chamber to the forming surface; and    (d) depositing the particles on the forming surface.    
     
     
         39 . The method of  claim 38 , further comprising defiberizing a fiber board with a hammermill to form the particles which are provided to the airflow.  
     
     
         40 . The method of  claim 38 , wherein the forming surface is rotated past the airflow transporting the particles.  
     
     
         41 . The method of  claim 40 , further comprising securing the particles to the forming surface with vacuum means.  
     
     
         42 . The method of  claim 38 , which further comprises scarfing the particles on the forming surface to redistribute the particles deposited on said forming surface.  
     
     
         43 . The method of  claim 38 , which further comprises providing an additive to the airborne particles passing through the forming chamber.  
     
     
         44 . The method of  claim 43 , wherein the additive is a SAP.  
     
     
         45 . The method of  claim 38 , wherein the first predetermined zone has a plurality of perforations defining an open area of about 30% to about 85% of the total area of the first predetermined zone; and the second predetermined zone has a plurality of perforations defining an open area of about 5% to about 25% of the total area of the second predetermined zone.  
     
     
         46 . The method of  claim 38 , wherein the first predetermined zone has a plurality of perforations defining an open area of about 40% to about 60% of the total area of the first predetermined zone; and the second predetermined zone has a plurality of perforations defining an open area of about 10% to about 22% of the total area of the second predetermined zone.  
     
     
         47 . The method of  claim 38 , wherein the first predetermined zone has a plurality of perforations defining an open area of about 45% to about 55% of the total area of the first predetermined zone; and the second predetermined zone has a plurality of perforations defining an open area of about 15% to about 20% of the total area of the second predetermined zone.  
     
     
         48 . The method of  claim 38 , further comprising providing on the forming surface a third predetermined area with a third air permeability, the third air permeability gradually increasing or decreasing along the longitudinal axis of said third predetermined area.  
     
     
         49 . The method of  claim 38 , further comprising a third predetermined area with a third air permeability and a fourth predetermined area with a fourth permeability, each air permeability gradually increasing or decreasing along the longitudinal axis of each of said third and fourth predetermined areas.  
     
     
         50 . The method of  claim 38 , wherein the third air permeability or the fourth air permeability gradually increases or decreases from about the first air permeability to about the second air permeability along the longitudinal axis of each of said third and fourth predetermined areas.  
     
     
         51 . The method of  claim 50 , wherein the gradual increase or decrease is characterized as a linear progression.  
     
     
         52 . The method of  claim 50 , wherein the gradual increase or decrease is characterized as a curved progression.  
     
     
         53 . A method for preparing an absorbent article, comprising the steps of: 
 (a) placing particles into an airflow;    (b) transporting the particles in the airflow through a forming chamber and to a forming surface mounted on a section of a rotating drum; and    (c) depositing the particles on the forming surface, said forming surface having a first predetermined zone and a second predetermined zone, said first predetermined zone having a first plurality of openings defining an area of about 30% to about 85% of the total area of the first predetermined zone, and said second predetermined zone having a second plurality of openings defining an area of about 5% to about 25% of the total area of the second predetermined zone.    
     
     
         54 . The method of  claim 53 , wherein the rotating drum comprises vacuum means for securing the particles to the forming surface.  
     
     
         55 . The method of  claim 53 , further comprising generating the particles in a hammermill positioned in sufficient proximity to the airflow to place said particles into said airflow.  
     
     
         56 . The method of  claim 53 , further comprising scarfing the particles on the forming surface to redistribute the particles deposited on said forming surface.  
     
     
         57 . The method of  claim 53 , further comprising placing an additive into the airflow containing the particles as said airflow passes through the forming chamber.  
     
     
         58 . The method of  claim 57 , wherein the additive is a SAP.  
     
     
         59 . The method of  claim 53 , wherein the first plurality of openings defines an area of about 40% to about 60% of the total area of the first predetermined zone; and the second plurality of openings defines an area of about 10% to about 22% of the total area of the second predetermined zone.  
     
     
         60 . The method of  claim 53 , wherein the first plurality of openings defines an area of about 45% to about 55% of the total area of the first predetermined zone; and the second plurality of openings defines an area of about 15% to about 20% of the total area of the second predetermined zone.  
     
     
         61 . The method of  claim 53 , wherein the forming surface comprises a forming screen.  
     
     
         62 . The method of  claim 61 , wherein the forming screen is a sheet metal forming screen.  
     
     
         63 . The method of  claim 53 , wherein the size of each opening is uniform with every other opening on the forming surface.  
     
     
         64 . The method of  claim 53 , wherein the diameter of each opening in the forming surface ranges from about 0.030 inches to about 0.050 inches.  
     
     
         65 . The method of  claim 53 , wherein the diameter of each opening in the forming surface ranges from about 0.036 inches to about 0.040 inches.  
     
     
         66 . The method of  claim 65 , wherein the first predetermined zone has about 24 openings per square inch to about 10,000 openings per square inch.  
     
     
         67 . The method of  claim 65 , wherein the second predetermined zone has about 4 openings per square inch to about 6,300 openings per square inch.  
     
     
         68 . The method of  claim 53 , further comprising providing a third predetermined zone on said forming surface, said third predetermined zone having a third plurality of openings defining a gradually increasing or decreasing area.  
     
     
         69 . The method of  claim 53 , further comprising providing a fourth predetermined zone on said forming surface, said fourth predetermined zone having a fourth plurality of openings defining a gradually increasing or decreasing area.  
     
     
         70 . An absorbent article, which comprises: 
 a first predetermined area having a first AUL;    a second predetermined area having a second AUL; and    wherein the ratio of the first AUL to the second AUL is about 1.25:1 to about 5:1.    
     
     
         71 . The absorbent article of  claim 70 , wherein the first predetermined area corresponds to the front of a garment comprising the absorbent article and the second predetermined area corresponds to the back of said garment.  
     
     
         72 . The article of  claim 70 , wherein the ratio of the first AUL to the second AUL is about 1.5:1 to about 2.5:1.  
     
     
         73 . The article of  claim 70 , wherein the ratio of the first AUL to the second AUL is about 2:1.  
     
     
         74 . The article of  claim 70 , wherein the first predetermined area has a first basis weight and the second predetermined area has a second basis weight.  
     
     
         75 . The article of  claim 70 , wherein the weight ratio of the first basis weight to the second basis weight is about 1.5:1 to about 3:1.  
     
     
         76 . The article of  claim 70 , wherein the weight ratio of the first basis weight to the second basis weight is about 1.6:1 to about 2.5:1.  
     
     
         77 . The article of  claim 70 , wherein the weight ratio of the first basis weight to the second basis weight is about 2:1.  
     
     
         78 . The article of  claim 70 , further comprising a third and a fourth predetermined area, wherein each of said third and fourth predetermined area has an AUL which gradually increases or decreases across the longitudinal direction of said area.  
     
     
         79 . The article of  claim 78 , wherein the gradual increase or decrease is linear and ranges between the first AUL and the second AUL.  
     
     
         80 . The article of  claim 70 , wherein the article comprises a disposable garment.  
     
     
         81 . The article of  claim 70 , wherein the article comprises a disposable waste-containment garment.  
     
     
         82 . The article of  claim 70 , wherein the article comprises a disposable diaper.  
     
     
         83 . The article of  claim 70 , wherein the article is the absorbent core of a disposable diaper.  
     
     
         84 . The article of  claim 70 , wherein the article comprises an adult incontinent protection garment.  
     
     
         85 . An absorbent article, which comprises: 
 a first predetermined area having a first FVAUL;    a second predetermined area having a second FVAUL; and    wherein the ratio of the first FVAUL to the second FVAUL is about 1.25:1 to about 5:1.    
     
     
         86 . The absorbent article of  claim 85 , wherein the first predetermined area corresponds to the front of a garment comprising the absorbent article and the second predetermined area corresponds to the back of said garment.  
     
     
         87 . The article of  claim 85 , wherein the ratio of the first FVAUL to the second FVAUL is about 1.5:1 to about 2.5:1.  
     
     
         88 . The article of  claim 85 , wherein the ratio of the first FVAUL to the second FVAUL is about 2:1.  
     
     
         89 . The article of  claim 85 , further comprising a third and a fourth predetermined area, wherein each of said third and fourth predetermined area has an FVAUL which gradually increases or decreases across the longitudinal direction of said area.  
     
     
         90 . The article of  claim 89 , wherein the gradual increase or decrease is linear and ranges between the first FVAUL and the second FVAUL.  
     
     
         91 . The article of  claim 85 , wherein the article comprises a disposable garment.  
     
     
         92 . The article of  claim 85 , wherein the article comprises a disposable waste-containment garment.  
     
     
         93 . The article of  claim 85 , wherein the article comprises a disposable diaper.  
     
     
         94 . The article of  claim 85 , wherein the article is the absorbent core of a disposable diaper.  
     
     
         95 . The article of  claim 85 , wherein the article comprises an adult incontinent protection garment.  
     
     
         96 . A formed fibrous article prepared by a process comprising the steps of: 
 (a) placing particles into an airflow;    (b) transporting the particles in the airflow through a forming chamber and to a forming surface mounted on a section of a rotating drum; and    (c) depositing the particles on the forming surface, said forming surface having a first predetermined zone and a second predetermined zone, said first predetermined zone having a first plurality of openings defining an area of about 30% to about 85% of the total area of the first predetermined zone, and said second predetermined zone having a second plurality of openings defining an area of about 5% to about 25% of the total area of the second predetermined zone.