Absorbent foam material, a method of producing it and an absorbent structure containing said foam material

Abstract

A liquid absorbent open-cell polymeric foam material having properties which makes it suitable for use as an absorbent structure in absorbent articles such as diapers, pant diapers, sanitary napkins, incontinence guards, wound dressings, bed protections etc., at which the foam material has an absorption rate at wetting of at least 0.4 ml/s for a round sample having the diameter 50 mm, a liquid distribution capacity at an inclination of 30° of at least 15 g/g and a liquid storage capacity of at least 9% measured through CRC (centrifuge retention capacity), at which the test liquid in all cases is synthetic urine. There is further referred to an absorbent structure containing the foam material.

1 . A liquid absorbent material comprising an open-cell polymeric foam material comprising either polysaccharide or polypeptide, the foam material comprising a distribution of pore sizes between 0 and 3 μm, the foam material having an absorption rate at wetting of at least 0.4 ml/s for a round sample having a 50 mm diameter, a liquid distribution capacity at an inclination of 30° of at least 15 g/g, a liquid storage capacity of at least 9% measured through centrifuge retention capacity, and an absorption of at least 4 g/g measured by pore volume distribution of total liquid amount in pores below 3 μm, for synthetic urine test liquid. 
     
     
         2 . The liquid absorbent material as claimed in  claim 1 , wherein the absorption rate at wetting is at least 0.5 ml/s, the liquid distribution capacity at an inclination of 30° is at least 16 g/g, and the liquid storage capacity measured through centrifuge retention capacity is at least 11%. 
     
     
         3 . The liquid absorbent material as claimed in  claim 1 , wherein the foam material contains fibers in its pore system. 
     
     
         4 . The liquid absorbent material as set forth in  claim 1 , wherein the liquid absorbent material is utilized as an absorbent structure in an absorbent article and the absorbent article is a diaper, a pant diaper, a sanitary napkin, an incontinence guard, a wound dressing, or a bed protection. 
     
     
         5 . The liquid absorbent material as set forth in  claim 1 , wherein the open-cell polymeric foam material is formed by a process wherein a removable phase is removed after a crosslinking step. 
     
     
         6 . The liquid absorbent material as set forth in  claim 5 , wherein the removable phase is water. 
     
     
         7 . An absorbent structure in an absorbent article, wherein the absorbent structure comprises a liquid absorbent material according to  claim 1 . 
     
     
         8 . The absorbent structure as claimed in  claim 7 , wherein said absorbent structure consists of said foam material. 
     
     
         9 . The absorbent structure as claimed in  claim 7 , wherein the foam material has a three-dimensional anatomic shape. 
     
     
         10 . The absorbent structure in an absorbent article as claimed in  claim 7 , wherein the absorbent article is a diaper, a pant diaper, a sanitary napkin, an incontinence guard, a wound dressing, or a bed protection. 
     
     
         11 . A liquid absorbent material comprising an open-cell polymeric foam material comprising either polysaccharide or polypeptide, the foam material having a first distribution of pore sizes between 0 and 3 μm and a second distribution of pore sizes between 3 and 100 μm, the foam material having an absorption rate at wetting of at least 0.4 ml/s for a round sample having a 50 mm diameter, a liquid distribution capacity at an inclination of 30° of at least 15 g/g, a liquid storage capacity of at least 9% measured through centrifuge retention capacity and an absorption of at least 4 g/g measured by pore volume distribution of total liquid amount in pores below 3 μm, for synthetic urine test liquid. 
     
     
         12 . A liquid absorbent material comprising an open-cell polymeric foam material comprising either polysaccharide or polypeptide, the foam material having a first distribution of pore sizes between 0 and 3 μm and a second distribution of pore sizes between 3 and 500 μm, the foam material having an absorption rate at wetting of at least 0.4 ml/s for a round sample having a 50 mm diameter, a liquid distribution capacity at an inclination of 30° of at least 15 g/g, a liquid storage capacity of at least 9% measured through centrifuge retention capacity and an absorption of at least 4 g/g measured by pore volume distribution of total liquid amount in pores below 3 μm, for synthetic urine test liquid. 
     
     
         13 . A liquid absorbent material comprising an open-cell polymeric foam material comprising either polysaccharide or polypeptide, the foam material having an absorption rate at wetting of at least 0.4 ml/s for a round sample having a 50 mm diameter, a liquid distribution capacity at an inclination of 30° of at least 15 g/g, a liquid storage capacity of at least 9% measured through centrifuge retention capacity, for synthetic urine test liquid, a first distribution of pores with a diameter less than 3 μm which produces an absorption of at least 4 g/g synthetic urine measured by pore volume distribution of total liquid amount in pores below 3 μm, and a second distribution of pores with a diameter between 3 and 100 μm which produces a capillary liquid absorption of at least 8 ml/g. 
     
     
         14 . The liquid absorbent material as claimed in  claim 13 , wherein the absorption in pores below 3 μm is at least 5 g/g synthetic urine. 
     
     
         15 . The liquid absorbent material as claimed in  claim 13 , wherein the capillary liquid absorption is at least 10 ml/g synthetic urine. 
     
     
         16 . The liquid absorbent material as claimed in  claim 13 , wherein the absorption in pores below 3 μm is at least 5 g/g synthetic urine and the capillary liquid absorption is at least 10 ml/g synthetic urine.