ABSORBENT SHEET EXHIBITING RESISTANCE TO MOISTURE PENETRATION
(19)AUSTRALIAN PATENT OFFICE(54)TitleABSORBENT SHEb I EXHIBITING RESISTANCE TO MOISTURE PENETRATION(21) Application No: 2003287516(22) Application Date: 2003.11.06(87) WIPONo: WO04/044320 (30) Priority Data (31) Number (32) Date (33) Country 60/424,434 2002.11.07US(43) Publication Date : 2004.06.03(43) Publication Journal Date : 2004.07.08(71) Applicant(s) FORT JAMES CORPORATION(72)Inventor(s)LUU, Phuong, V.; EDWARDS, Steven,L; WHITE, David, W.; SCHAUER, Brigitte,K.; HYNNEK, Martin, A. (H) Application NoAU2003287516 A1(19)AUSTRALIAN PATENT OFFICE(54)TitleABSORBENT SHEb I EXHIBITING RESISTANCE TO MOISTURE PENETRATION(21) Application No: 2003287516(22) Application Date: 2003.11.06(87) WIPONo: WO04/044320 (30) Priority Data (31) Number (32) Date (33) Country 60/424,434 2002.11.07US(43) Publication Date : 2004.06.03(43) Publication Journal Date : 2004.07.08(71) Applicant(s) FORT JAMES CORPORATION(72)Inventor(s)LUU, Phuong, V.; EDWARDS, Steven,L; WHITE, David, W.; SCHAUER, Brigitte,K.; HYNNEK, Martin, A. An absorbent paper sheet is treated with an aqueous wax dispersion such that the sheet includes a fused wax and emulsifier residue in an amount of from about 1 to about 20 weight percent of the sheet based on the combined weight of the fiber, wax residue and an emulsifier residue in the sheet. The fused wax emulsion operates to make at least one surface of the sheet laterally hydrophobic, exhibiting a moisture penetration delay of at least about 2 seconds and less than about 40 seconds as well as a typical contact angle with water at one minute of at least about 50 degrees. There is thus provided absorbent products which exhibit both absorbency and resistance to moisture penetration. The treated sheet further exhibits microbial barrier properties, impeding transfer of bacteria, for example, through the sheet. There are produced tissue products which resist moisture penetration from propelled liquids as well as sequester sorbed liquids in the interior of the tissue. An absorbent cellulosic web resistant to moisture penetration, said web having an absorbency of at least 2 grams water per gram of web and a moisture penetration delay of a 0.1 ml water droplet of at least about 2 seconds on its wax treated surface, and being obtainable by a method comprising:
(a) wetting at least one surface of the web with an aqueous dispersion including a wax and an emulsifier, wherein the wax is present in an amount of from 1 to 20 wt% based on the amount of wax and cellulosic fiber in the web; and (b) heating the web above the melting temperature of the wax to fuse the wax of the dispersion and to provide a hydrophobic surface on the web; The absorbent cellulosic web resistant to moisture penetration of claim 1, wherein in step (a) the wax is present in an amount of from 2 to 10 wt% based on the amount of wax and cellulosic fiber in the web. The absorbent cellulosic web resistant to moisture penetration of claim 1 or 2, wherein the web exhibits an absorbency of at least 4 grams water per gram of web. The absorbent cellulosic web resistant to moisture penetration of claim 1 or 2, wherein the web exhibits an absorbency of at least 6 grams water per gram of web. The absorbent cellulosic web resistant to moisture penetration of any of claims 1 to 4, wherein at least 60% of the air permeability of the web, as measured at a water pressure of 0.5 inches (1.27 cm), is retained as compared with the untreated web. The absorbent cellulosic web resistant to moisture penetration of any of claims 1 to 4, wherein at least 80% of the air permeability of the web, as measured at a water pressure of 0.5 inches (1.27 cm), is retained as compared with the untreated web. The absorbent cellulosic web resistant to moisture penetration of any of claims 1 to 6, wherein the web exhibits a moisture penetration delay of a 0.1 ml water droplet of at least about 5 seconds on its wax treated surface. The absorbent cellulosic web resistant to moisture penetration of any of claims 1 to 6, wherein the web exhibits a moisture penetration delay of a 0.1 ml water droplet of at least about 10 seconds on its wax treated surface. The absorbent cellulosic web resistant to moisture penetration of any of claims 1 to 8, wherein the web exhibits an air permeability of from 15 ft3/min-ft2 to 45 ft3/min-ft2 at 0.5 inches of water. The absorbent cellulosic web resistant to moisture penetration of any of claims 1 to 8, wherein the web exhibits an air permeability of from 50 ft3/min-ft2 to 150 ft3/min-ft2 at 0.5 inches of water. The absorbent cellulosic web resistant to moisture penetration of any of claims 1 to 10, wherein the web is repulpable. The absorbent cellulosic web resistant to moisture penetration of any of claims 1 to 10, wherein the web is dispersible. The absorbent cellulosic web resistant to moisture penetration of any of claims 1 to 12, wherein the wax comprises a wax selected from the group consisting of microcrystalline waxes, carnauba waxes, polyolefin waxes, polyurethane waxes, montan waxes, paraffin waxes, Fischer-Tropsch waxes and mixtures thereof. The absorbent cellulosic web resistant to moisture penetration of claim 13, wherein the wax is a microcrystalline wax and the wax dispersion includes an emulsifier selected from the group consisting of anionic emulsifiers and non-ionic emulsifiers. A multi-ply absorbent cellulosic product comprising a web having an absorbency of at least 2 grams water per gram of web and a moisture penetration delay of a 0.1 ml water droplet of at least about 2 seconds on its wax treated surface, said product being obtainable by a method comprising:
(a) wetting at least one surface of the web with an aqueous dispersion including a wax and an emulsifier, wherein the wax is present in an amount of from 2 to 10 wt% based on the amount of wax and cellulosic fiber in the web; (b) heating the web above the melting temperature of the wax to fuse the wax of the dispersion and to provide a hydrophobic surface on the web; and (c) plying the web with at least one additional ply; The multi-ply absorbent cellulosic product of claim 15, wherein the hydrophobic surface of the treated web is internally disposed in the product. The multi-ply absorbent cellulosic product of claim 15, wherein the plies are glue-bonded. Use of the web of any of claims 1 to 14 in a tissue product.