SYNTHETIC SURFACTANT-FREE FINISH, SHEET HAVING SYNTHETIC SURFACTANT-FREE FINISH, ARTICLES HAVING SHEET WITH SYNTHETIC SURFACTANT-FREE FINISH, AND RELATED METHODS
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).