Multi-layer absorbent wound dressing

Abstract

A multi-layer wound dressing comprising at least two absorbent layers, and materials for forming absorbent layers are provided. The absorbent layers have different absorbencies, with the layer closest to the wound having a lower absorbency than the layer furthest from the wound. The wound dressing typically contains additional non-absorbing layers, such as a backing film and wound-facing film. The dressing provides absorbency of wound exudates while preventing the absorbent material from entering the wound. In specific implementations the dressing is substantially transparent prior to application to a wound, as well as after application to the wound when body fluids have been absorbed.

1 . A multi-layer wound dressing comprising: 
 a first absorbent layer with an absorbency greater than 300 percent; and    a second absorbent, non-disintegrating layer in contact with the first absorbent layer, wherein the wound dressing is configured to be positioned on a patient's wound such that the second absorbent layer is between the first absorbent layer and the wound; and wherein the first absorbent layer is substantially insoluble in water.    
   
   
       2 . The multi-layer wound dressing of  claim 1 , wherein the first absorbent layer comprises a reaction product of a hydrophilic, ethylenically unsaturated monomer; an acrylic acid ester of a non-tertiary alcohol having 4 to 14 carbon atoms; and a polar, ethylenically unsaturated monomer.  
   
   
       3 . The multi-layer wound dressing of  claim 2 , wherein the first absorbent layer comprises the reaction product of about 50 to 80 parts by weight of the hydrophilic, ethylenically unsaturated monomer; about 5 to 30 parts by weight of the acrylic acid ester of a non-tertiary alcohol having from 4 to 14 carbon atoms; and about 10 to 30 parts by weight of the polar, ethylenically unsaturated monomer.  
   
   
       4 . The multi-layer wound dressing of  claim 1 , wherein the first absorbent layer has an absorbency at least 100 percent greater than the absorbency of the second absorbent, non-disintegrating layer.  
   
   
       5 . The multi-layer wound dressing of  claim 1 , wherein the second absorbent layer has an absorbency of at least 50 percent.  
   
   
       6 . The multi-layer wound dressing of  claim 1 , wherein the second absorbent, non-disintegrating layer is adhesive.  
   
   
       7 . A body fluid absorbing material comprising the reaction product of: 
 less than about 68 parts by weight of an acrylic acid ester of a non-tertiary alcohol having from 4 to 14 carbon atoms;    greater than about 28 parts by weight of a hydrophilic, ethylenically unsaturated monomer; and    at least about 4 parts by weight of a partially neutralized ethylenically unsaturated carboxylic acid monomer.    
   
   
       8 . The body fluid absorbing material of  claim 7 , wherein less than 50 percent of the carboxylic acid monomer is neutralized.  
   
   
       9 . The body fluid absorbing material of  claim 7 , wherein from 10 to 35 percent of the carboxylic acid monomer is neutralized.  
   
   
       10 . The body fluid absorbing material of  claim 7 , wherein the acrylic acid ester comprises a methacrylic acid ester.  
   
   
       11 . The body fluid absorbing material of  claim 7 , wherein the hydrophilic, ethylenically unsaturated monomer comprises methoxy poly(ethyleneglycol) acrylate.  
   
   
       12 . The body fluid absorbing material of  claim 7 , wherein the partially neutralized carboxylic acid monomer comprises from about 4 to 30 parts by weight of the body fluid absorbing material.  
   
   
       13 . The body fluid absorbing material of  claim 7 , wherein less than 40 mole percent of the carboxylic acid monomer is neutralized.  
   
   
       14 . The body fluid absorbing material of  claim 7 , wherein the carboxylic acid monomer is neutralized by a base selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, triethylamine, sodium ethoxide, sodium methoxide, or combinations thereof.  
   
   
       15 . A body fluid absorbing material comprising the reaction product of: 
 less than about 68 parts by weight of an acrylic acid ester of a non-tertiary alcohol having from 4 to 14 carbon atoms;    greater than about 28 parts by weight of a hydrophilic, ethylenically unsaturated monomer; and    at least about 4 parts by weight of N-vinyl acetamide.    
   
   
       16 . The body fluid absorbing material of  claim 15 , wherein the acrylic acid ester comprises a methacrylic acid ester.  
   
   
       17 . The body fluid absorbing material of  claim 15 , wherein the hydrophilic, ethylenically unsaturated monomer comprises methoxy poly(ethyleneglycol) acrylate.