Method and Apparatus for Making an Absorbent Structure Comprising Channels

Abstract

The present invention relates to an apparatus and method for making an absorbent structure for an absorbent article, comprising a supporting sheet and thereon an absorbent layer, the absorbent layer comprising an absorbent material. According to the present invention a first moving endless surface is provided which has one or more substantially longitudinally extending first mating strips, and at least one further auxiliary moving endless surface is provided which acts against the first mating strips. Pressure is applied between the first moving endless surface and the auxiliary moving endless surface to the first and second supporting sheets at least within a part of the area of the channels, so as to adhere together the first and second supporting sheets.

What is claimed is: 
     
         1 . An apparatus for making an absorbent structure for an absorbent article, comprising a first and second supporting sheet and therebetween an absorbent layer, the absorbent layer comprising an absorbent material, the apparatus comprising:
 a) transfer devices for transferring first and second supporting sheets to first and second moving endless surfaces;   b) a feeder for feeding the absorbent material onto at least the first supporting sheet at a depositing point on the first moving endless surface, the absorbent material forming absorbent regions upon the first supporting sheet, and one or more channels between the absorbent regions, the channels being substantially free of absorbent material;   c) an adhesive applicator for applying adhesive to at least one of the first and second supporting sheets, at least within a region of the channels;   wherein the first moving endless surface has one or more substantially longitudinally extending first mating strips, and at least one further auxiliary moving endless surface acting upon each other by applying pressure to the first and second supporting sheets at least within a part of an area of the channels, so as to adhere together the first and second supporting sheets.   
     
     
         2 . An apparatus according to  claim 1  wherein the auxiliary moving endless surface comprises second mating strips wherein the first mating strips are made from an elastic material, and the second mating strips are made from a metallic material. 
     
     
         3 . An apparatus according to  claim 2  wherein the first mating strips are made from silicone. 
     
     
         4 . An apparatus according to  claim 2  wherein the second mating strips are made from steel. 
     
     
         5 . An apparatus according to  claim 1 , wherein the first moving endless surface, comprises an outer shell that comprises one or more air permeable or partially air permeable receptacle(s) for receiving the first supporting sheet thereon, and whereby the outer shells are connected to one or more vacuum systems for facilitating retention of the first supporting sheet and/or the absorbent material thereon. 
     
     
         6 . An apparatus according to  claim 1 , whereby the receptacle further comprise a multitude of substantially longitudinally extending rods, spaced apart from one another in a transverse direction, each rod having a maximum width dimension of at least about 0.3 mm and less than about 2.5 mm, the rods each having an average height dimension of at least about 1 mm. 
     
     
         7 . An apparatus according to  claim 1 , whereby the feeder comprises a reservoir formed by a multitude of cavities. 
     
     
         8 . An apparatus according to  claim 5  whereby the cavities and/or grooves, that are directly adjacent a raised strip, have a volume that is more than a volume of one or more, or all of neighboring cavities that are not directly adjacent the raised strip. 
     
     
         9 . An apparatus according to  claim 1 , wherein the feeder is a particulate superabsorbent polymer material feeder. 
     
     
         10 . An apparatus according to  claim 1 , comprising a second adhesive applicator downstream from the depositing point. 
     
     
         11 . A method for making an absorbent structure comprising a first and second supporting sheet and thereon an absorbent layer of absorbent material, the method comprising the steps of:
 a) transferring first and second supporting sheets to first and second moving endless surfaces;   b) feeding the absorbent material onto at least the first supporting sheet at a depositing point on the first moving endless surface, the absorbent material forming absorbent regions and one or more channels between the absorbent regions, the channels being substantially free of absorbent material;   c) applying adhesive to at least one of the first and second supporting sheets, at least within a region of the channels;   characterized in that the first moving endless surface comprises one or more substantially longitudinally extending first mating strips, and wherein at least one further auxiliary moving endless surface, and wherein the method further comprises the step of applying pressure through the first and second mating strips and the auxiliary moving endless surface to the first and second supporting sheets at least within a part of an area of the channels, so as to adhere together the first and second supporting sheets.   
     
     
         12 . A method according to  claim 11  wherein the auxiliary moving endless surface comprises second mating strips. 
     
     
         13 . A method according to  claim 11 , whereby the absorbent material is a particulate superabsorbent polymer material. 
     
     
         14 . A method according to  claim 11 , comprising the step of providing a first adhesive application unit, and applying an adhesive to the supporting sheet, prior to deposition of the absorbent material thereon. 
     
     
         15 . A method according to  claim 11  comprising the step of providing a second adhesive application unit, and applying an adhesive to the absorbent structure prior to removing it from the first moving endless surface, or immediately subsequent thereto.