Absorbent hygiene product

• US 20050159720A1
• Filed: 12/18/2002
• Published: 07/21/2005
• Est. Priority Date: 12/20/2001
• Status: Abandoned Application

• Current Assignee: Freudenberg Nonwovens LP (Freudenberg & Company KG)
• Original Assignee: SciMat Limited (Crane Company)
• Inventors: Cook, John Anthony, Bekkaoui, Ali, Gentilcore, Giovanni
• Application Number:
  US10/498,734
• Publication Number:
  US 20050159720A1
• Time in Patent Office: Days
• US Class Current: 604/367
• CPC Class Codes: A61L 15/24 Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof A61L15/225 takes precedence
• CPC Class Codes: A61L 15/425 Porous materials, e.g. foams or sponges
• CPC Class Codes: B32B 5/26 another layer next to it also being fibrous or filamentary relative arrangement of fibres or filaments of different layers B32B5/12
• CPC Class Codes: C08F 255/00 Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00
• CPC Class Codes: C08F 255/02 on to polymers of olefins having two or three carbon atoms
• CPC Class Codes: C08L 23/10 Homopolymers or copolymers of propene
• CPC Class Codes: C08L 23/12 Polypropene
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 51/06 grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond

Abstract

Absorbent hygiene products comprising a core of an absorbent material and a top sheet through which fluid to be absorbed passes for absorption by the absorbent material are disclosed. The top sheet is porous and comprises a sheet having surfaces of a hydrophobic polymeric material modified by a graft copolymerization reaction between those surfaces and a vinyl monomer having a group capable of exhibiting hydrophilic properties. The graft polymerization reaction comprising exposure of the sheet to ultraviolet radiation while impregnated with a solution of the vinyl monomer. The grafted vinyl monomer comprises a substantially uniform coating of the sheet surface and having a mean thickness not more than about 3.0 μm. Methods for producing this absorbent hygiene product are also disclosed.

Claims

1-23. -23. (canceled)

24. An absorbent hygiene product comprising a core of an absorbent material and a top sheet through which fluid to be absorbed passes for absorption by said absorbent material, said top sheet being porous and comprising a sheet having surfaces comprising a hydrophobic polymeric material modified by a graft copolymerization reaction between said surfaces and a vinyl monomer having a group capable of exhibiting hydrophilic properties, said graft polymerization reaction comprising exposure of said sheet to ultraviolet radiation while impregnated with a solution of said vinyl monomer.

25. The hygiene product of claim 24 comprising trace quantities of an initiator for said graft polymerization reaction by which an atomic species has been abstracted from said hydrophobic polymer material to form a polymer radical on said sheet surface.

26. The hygiene product of claim 24 wherein said vinyl monomer comprises an ethylenically unsaturated acid or an ester thereof.

27. The hygiene product of claim 24 wherein said group capable of exhibiting hydrophilic properties comprises a salt of an ethylenically unsaturated acid.

28. The hygiene product of claim 24 wherein said hydrophobic polymeric material of said sheet comprises at least one polyolefin.

29. The hygiene product of claim 28 wherein said hydrophobic polymeric material of said sheet comprises polypropylene.

30. The hygiene product of claim 24 wherein said top sheet has a mean thickness of less than about 400 μ

m.

31. The hygiene product of claim 24 wherein said sheet comprises a fabric formed from fibers having a surface comprising said hydrophobic polymeric material.

32. The hygiene product of claim 31 wherein at least about 40% by weight of the material of said fibers comprises polypropylene.

33. The hygiene product of claim 31 wherein said fibers have a mean thickness of less than about 30 μ

m.

34. The hygiene product of claim 31 wherein said top sheet comprises a laminate of a first nonwoven fabric and a second nonwoven fabric.

35. The hygiene produce of claim 34 wherein said first nonwoven fabric comprises spun fibers and said second nonwoven fabric comprises a melt-blown fabric.

36. The hygiene product of claim 34 wherein said fibers of said second nonwoven fabric have a mean thickness of not greater than about 8 μ

m.

37. The hygiene product of claim 34 wherein the ratio of the weight of said fibers of said second nonwoven fabric to the weight of said fibers of said entire laminate is at least about 0.1.

38. The hygiene product of claim 33 wherein said laminate includes a third fabric.

39. A method of making an absorbent hygiene product comprising a core of an absorbent material and a top sheet through which fluid to be absorbed passes for absorption by said absorbent material, said method comprising impregnating a porous sheet having surfaces which comprise a hydrophobic polymeric material with a solution of a vinyl monomer having a group capable of exhibiting hydrophilic properties, exposing said impregnated sheet to ultraviolet radiation to cause said vinyl monomer to copolymerize with said hydrophobic polymer material of said sheet, drying and finishing said sheet to produce a top sheet, and laminating said top sheet with a core of absorbent material.

40. The method of claim 39 wherein said solution of said vinyl monomer comprises a solvent which does not evaporate significantly during the step of exposing said impregnated sheet to said ultraviolet radiation.

41. The method of claim 39 wherein said solution of said vinyl monomer comprises a solvent which comprises at least about 50 wt. % water based on the total weight of said solution apart from said vinyl monomer component and any other significant functional components.

42. The method of claim 39 wherein said solution of said vinyl monomer comprises about 5 wt. % of an organic solvent.

43. The method of claim 39 including treating said sheet mechanically to encourage impregnation of said sheet by said vinyl monomer solution.

44. The method of claim 39 wherein said vinyl monomer solution comprises an initiator which abstracts an atomic species from said hydrophobic polymer material of said sheet surface to form a polymer radical on said sheet surface.

45. The method of claim 39 wherein said vinyl monomer comprises an acid, said method including neutralizing said acid to at least partially convert said acid to a salt.

46. The method of claim 45 wherein said salt is selected from the group consisting of sodium salts and potassium salts.

47. An absorbent hygiene product comprising a core of an absorbent material and a top sheet through which fluid to be absorbed passes for absorption by said absorbent material, said top sheet being porous and comprising a sheet having surfaces provided by a hydrophobic polymeric material modified by a graft copolymerization reaction between said surfaces and a vinyl monomer having a group capable of exhibiting hydrophilic properties, said grafted vinyl monomer comprising a substantially uniform coating on said sheet surface and having a mean thickness not more than about 3.0 μ

m.