Stiff Nanocomposite Film for Use in an Absorbent Article

Patent metadata

Field	Value
Publication number	US-2016325005-A1
Application number	US-201514914263-A
Country	US
Kind code	A1
Filing date	Jan 30, 2015
Priority date	Jan 31, 2014
Publication date	Nov 10, 2016
Grant date	—

Abstract

A thin nanocomposite film for use in an absorbent article (e.g., sanitary napkin) is provided. The film contains a first ethylene polymer having a density of about 0.94 g/cm3 or less, second ethylene polymer having a density of greater than 0.94 g/cm3, and nanoclay having an organic surface treatment. The present inventors have discovered that through selective control over the particular type and concentration of the components used to form the film, as well as the manner in which it is formed, the properties of the film can be significantly improved.

First claim

1 . An absorbent article comprising a liquid permeable layer, a generally liquid-impermeable layer, and an absorbent core positioned between the liquid permeable layer and the generally liquid-impermeable layer, wherein the absorbent article contains a film having a thickness of about 50 micrometers or less, the film containing a layer that is formed from a polymer composition, wherein the polymer composition contains a first ethylene polymer having a density of about 0.94 g/cm 3 or less, a second ethylene polymer having a density of greater than 0.94 g/cm 3 , and a nanoclay having an organic surface treatment, wherein the weight ratio of the first ethylene polymer to the second ethylene polymer is from about 0.1 to about 10.

2 . The absorbent article of claim 1 , wherein ethylene polymers having a density of about 0.94 g/cm 3 or less constitute from about 5 wt. % to about 90 wt. % of the polymer composition and ethylene polymers having a density of greater than about 0.94 g/cm 3 constitute from about 5 wt. % to about 90 wt. % of the polymer composition.

3 . The absorbent article of claim 1 , wherein the nanoclay constitutes from about 0.5 wt. % to about 20 wt. % of the polymer composition.

4 . The absorbent article of claim 1 , wherein the first ethylene polymer, the second ethylene polymer, or both include a copolymer of ethylene and an α-olefin.

5 . The absorbent article of claim 1 , wherein the first ethylene polymer includes linear low density polyethylene, low density polyethylene, or a mixture thereof.

6 . The absorbent article of claim 1 , wherein the second ethylene polymer includes high density polyethylene.

7 . The absorbent article of claim 1 , wherein the nanoclay includes a phyllosilicate.

8 . The absorbent article of claim 7 , wherein the phyllosilicate includes a montmorillonite or a salt thereof.

9 . The absorbent article of claim 1 , wherein the nanoclay includes platelets having an average thickness of from about 0.2 to about 100 nanometers.

10 . The absorbent article of claim 1 , wherein the organic surface treatment includes a quaternary onium.

11 . The absorbent article of claim 1 , wherein the polymer composition further comprises a polyolefin compatibilizer that includes an olefin component and a polar component.

12 . The absorbent article of claim 11 , wherein the polyolefin compatibilizer includes a carboxylic acid or carboxylic acid anhydride grafted polyolefin.

13 . The absorbent article of claim 1 , wherein the film exhibits a Young's modulus in the machine direction of from about 150 to about 1000 Megapascals, a Young's modulus in the cross-machine direction of from about 200 to about 1200 Megapascals, or a combination thereof.

14 . (canceled)

15 . The absorbent article of claim 1 , wherein the film exhibits a peak elongation in the machine direction of about 200% or more and an ultimate tensile strength in the machine direction of from about 15 to about 150 Megapascals.

16 . The absorbent article of claim 1 , wherein the film exhibits a peak elongation in the cross-machine direction of about 700% or more and an ultimate tensile strength in the cross-machine direction of from about 15 to about 150 Megapascals.

17 . The absorbent article of claim 1 , wherein absorbent article further comprises at least one wing that extends laterally from an edge of the article, wherein the wing contains the film.

18 . The absorbent article of claim 1 , wherein the generally liquid-impermeable layer is a backsheet of the absorbent article, the backsheet containing the film.

19 . A film having a thickness of about 50 micrometers or less, wherein the film contains a layer that is formed from a polymer composition, the polymer composition containing from about 5 wt. % to about 90 wt. % of a first ethylene polymer having a density of about 0.94 g/cm 3 or less, from about 5 wt. % to about 90 wt. % of a second ethylene polymer having a density of greater than 0.94 g/cm 3 , and from about 0.5 wt. % to about 20 wt. % of a nanoclay having an organic surface treatment, wherein the weight ratio of the first ethylene polymer to the second ethylene polymer is from about 0.1 to about 10, wherein the film exhibits a Young's modulus in the machine direction of from about 150 to about 1000 Megapascals.

20 . The film of claim 19 , wherein the film exhibits a Young's modulus in the cross-machine direction of from about 200 to about 1200 Megapascals.

21 . The film of claim 19 , wherein the film exhibits a peak elongation in the machine direction of about 200% or more and an ultimate tensile strength in the machine direction of from about 15 to about 150 Megapascals.

22 . The film of claim 19 , wherein the film exhibits a peak elongation in the cross-machine direction of about 700% or more and an ultimate tensile strength in the cross-machine direction of from about 15 to about 150 Megapascals.

23 . The film of claim 19 , wherein the nanoclay includes a montmorillonite or a salt thereof.

24 . The film of claim 19 , wherein the nanoclay includes platelets having an average thickness of from about 0.2 to about 100 nanometers.

25 . The film of claim 19 , wherein the organic surface treatment includes a quaternary onium.

26 . The film of claim 19 , wherein the film is multi-layered and contains a base layer and/or skin layer formed from the polymer composition.

27 . The film of claim 19 , wherein the first ethylene polymer includes linear low density polyethylene, low density polyethylene, or a mixture thereof.

28 . The film of claim 19 , wherein the second ethylene polymer includes high density polyethylene.

29 . The film of claim 19 , wherein the film exhibits a normalized noise level of about 2.5 or less as determined at a frequency of 4,000 Hz, wherein the normalized noise level is determined by dividing the noise level of the film by the noise level of an ambient environment.

30 . A method for forming the film of claim 19 , the method comprising:
melt blending the first ethylene polymer, the second ethylene polymer, and the nanoclay; applying the polymer composition to a surface to form the film.

31 . The method of claim 30 , wherein the melt blending occurs in a twin screw extruder.

32 . The method of claim 30 , wherein the nanoclay is in the form of a powder.

Assignees

• Kimberly Clark Co

Inventors

• Wang James Hongxue
• Chen Feng
• Wideman Gregory J
• Faulks Michael J
• Mleziva Mark M

Classifications

• C08L23/06

  Polyethylene · CPC title

• A61L15/18

  containing inorganic materials · CPC title

• A61F13/472

  specially adapted for female use · CPC title

• A61F2013/15292

  Resistance, i.e. modulus or strength · CPC title

• A61L15/24

  Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof {(A61L15/225 takes precedence)} · CPC title