Synthetic surfactant-free finish, sheet having synthetic surfactant-free finish, articles having sheet with synthetic surfactant-free finish, and related methods

Abstract

Nonwoven (and film) topsheet and acquisition/distribution materials treated with a hydrophilic, synthetic surfactant-free finish, absorbent articles for infant or incontinence care that contain these materials, and methods for apply such finishes and/or making such absorbent articles.

1 - 15 . (canceled) 
     
     
         16 . A method of imparting hydrophilic properties to a sheet of polymeric material, the method comprising:
 dissolving a water-soluble protein in water to form a 0.5-10% aqueous solution of the water-soluble protein having a surface tension of less than 49 milliNewtons per meter (mN/m);   maintaining the aqueous solution at a temperature for a period of time sufficient to thermally denature at least a portion of the protein;   applying the aqueous solution to a sheet of polymeric material; and   drying the sheet such that at least a portion of the protein is retained on a surface of the sheet;   where the aqueous solution is substantially free of synthetic surfactants.   
     
     
         17 . The method of  claim 16 , wherein the sheet comprises a nonwoven fabric or a film. 
     
     
         18 . The method of  claim 16 , further comprising, prior to applying the aqueous solution to the sheet:
 admixing the water-soluble protein in water;   heating the water to a temperature in the range of 40° Celsius (C) to 99° C.; and   stirring the admixture to dissolve the water-soluble protein in the water.   
     
     
         19 . The method of  claim 18 , wherein the water is heated before admixing the water-soluble protein. 
     
     
         20 . The method of  claim 18 , wherein the temperature of the water is maintained at a temperature of from 40° C. to 99° C. during at least a portion of the stirring. 
     
     
         21 . The method of  claim 19 , wherein the temperature of the water is maintained at a temperature of from 40° C. to 99° C. for a period of time sufficient to thermally denature at least a portion of the water-soluble protein. 
     
     
         22 . The method of  claim 18 , further comprising:
 adjusting the pH of the admixture of water and water-soluble protein prior to heating the admixture.   
     
     
         23 . The method of  claim 16 , wherein the temperature of the solution is in the range of 20° C. to 40° C. during at least a portion of applying the aqueous solution to the sheet. 
     
     
         24 . The method of  claim 16 , wherein applying the aqueous solution to the sheet comprises:
 immersing the sheet a first time in the aqueous solution; and   immersing the sheet a second time in the aqueous solution.   
     
     
         25 . The method of  claim 24 , further comprising:
 calendaring the sheet between immersing the sheet the first time and immersing the sheet the second time.   
     
     
         26 . The method of  claim 16 , wherein applying the aqueous solution to the sheet is performed with at least one coating apparatus selected from the group consisting of: a slot die, a knife coater, a kiss coater, a gravure printer, a multiple-roller coating apparatus, and a screen coating apparatus. 
     
     
         27 . The method of  claim 16 , wherein the aqueous solution comprises a preservative. 
     
     
         28 . The method  claim 27 , wherein the preservative comprises one or more preservatives selected from the group consisting of elemental silver, Japanese honeysuckle, one of more tocopherols, and mixtures thereof. 
     
     
         29 . The method of  claim 16 , wherein the protein comprises soy protein isolate (SPI).