Anisotropic polymeric material

Patent metadata

Field	Value
Publication number	US-9957369-B2
Application number	US-201414909575-A
Country	US
Kind code	B2
Filing date	Jun 6, 2014
Priority date	Aug 9, 2013
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

A polymeric material having anisotropic properties, such as mechanical properties (e.g., modulus of elasticity), thermal properties, barrier properties (e.g., breathability), and so forth, is provided. The anisotropic properties can be achieved for a single, monolithic polymeric material through selective control over the manner in which the material is formed. For example, one or more zones of the polymeric material can be strained to create a unique network of pores within the strained zone(s). However, zones of the polymeric material that are not subjected to the same degree of deformational strain will not have the same pore volume, and in some cases, may even lack a porous network altogether.

First claim

What is claimed is:

1. A polymeric material, wherein the polymeric material is formed from a thermoplastic composition containing a continuous phase that includes a matrix polymer, and further wherein a microinclusion additive and nanoinclusion additive are dispersed within the continuous phase in the form of discrete domains, wherein the polymeric material defines a first zone that is contiguous to a second zone, wherein a porous network is formed within the first zone such that the first zone exhibits a greater pore volume than the second zone.

2. The polymeric material of claim 1 , wherein the average pore volume of the material within the first zone is from about 15% to about 80% per cm 3 .

3. The polymeric material of claim 2 , wherein the average pore volume of the material within the second zone is less than 15%.

4. The polymeric material of claim 1 , wherein the ratio of the density of the material within the first zone to the density of the material within the second zone is from about 0.1 to about 0.95.

5. The polymeric material of claim 1 , wherein the density of the material within the first zone is about 1.2 g/cm 3 or less.

6. The polymeric material of claim 1 , wherein the ratio of the water vapor transmission rate of the material within the first zone to the water vapor transmission rate of the material within the second zone is from about 0.1 to about 0.95.

7. The polymeric material of claim 1 , wherein the water vapor transmission rate of the material within the first zone is about 500 g/m 2 -24 hours or more.

8. The polymeric material of claim 1 , wherein the ratio of the modulus of elasticity of the material within the first zone to the modulus of elasticity of the material within the second zone is from about 0.1 to about 0.95.

9. The polymeric material of claim 1 , wherein the modulus of elasticity of the material within the first zone is about 2400 MPa or less.

10. The polymeric material of claim 1 , wherein the ratio of the notched Charpy impact strength of the material within the first zone to the notched Charpy impact strength of the material within the second zone is from about 0.1 to about 0.95.

11. The polymeric material of claim 1 , wherein the notched Charpy impact strength within the first zone is about 10 kJ/m 2 or more.

12. The polymeric material of claim 1 , wherein the ratio of the thermal admittance of the material within the first zone to the thermal admittance of the material within the second zone is from about 0.1 to about 0.95.

13. The polymeric material of claim 1 , wherein the thermal admittance within the first zone is about 1000 W/m 2 K or less.

14. The polymeric material of claim 1 , wherein the porous network includes a plurality of nanopores having an average cross-sectional dimension of about 800 nanometers or less.

15. The polymeric material of claim 14 , wherein the nanopores constitute about 20 vol. % or more of the total pore volume of the material within the first zone.

16. The polymeric material of claim 15 , wherein the porous network further includes micropores.

17. The polymeric material of claim 16 , wherein the aspect ratio of the micropores is from about 1 to about 30.

18. The polymeric material of claim 1 , wherein the continuous phase constitutes from about 60 wt. % to about 99 wt. % of the thermoplastic composition.

19. The polymeric material of claim 1 , wherein the matrix polymer includes a polyester or polyolefin.

20. The polymeric material of claim 19 , wherein the polyester has a glass transition temperature of about 0° C. or more.

21. The polymeric material of claim 19 , wherein the polyester includes polylactic acid.

22. The polymeric material of claim 1 , wherein the microinclusion additive is polymeric.

23. The polymeric material of claim 22 , wherein the microinclusion additive includes a polyolefin.

24. The polymeric material of claim 1 , wherein the ratio of the solubility parameter for the matrix polymer to the solubility parameter of the microinclusion additive is from about 0.5 to about 1.5, the ratio of the melt flow rate for the matrix polymer to the melt flow rate of the microinclusion additive is from about 0.2 to about 8, and/or the ratio of the Young's modulus elasticity of the matrix polymer to the Young's modulus of elasticity of the microinclusion additive is from about 1 to about 250.

25. The polymeric material of claim 1 , wherein the nanoinclusion additive is a functionalized polyolefin.

26. The polymeric material of claim 25 , wherein the nanoinclusion additive is a polyepoxide.

27. The polymeric material of claim 1 , wherein the microinclusion additive constitutes from about 1 wt. % to about 30 wt. % of the composition, based on the weight of the continuous phase.

28. The polymeric material of claim 1 , wherein the nanoinclusion additive constitutes from about 0.05 wt. % to about 20 wt. % of the composition, based on the weight of the continuous phase.

29. The polymeric material of claim 1 , wherein the thermoplastic composition further comprises an interphase modifier.

30. The polymeric material of claim 1 , wherein the material defines multiple first zones, multiple second zones, or a combination thereof, at least one of the first zones being contiguous to at least one of the second zones.

31. The polymeric material of claim 1 , wherein a second zone is positioned between two first zones.

32. A method for forming the polymeric material of claim 1 , the method comprising straining the first zone of the polymeric material to achieve the porous network.

33. The method of claim 32 , wherein the second zone is not strained.

34. The method of claim 32 , wherein the second zone is strained to a lesser degree than the first zone.

35. The method of claim 32 , wherein the second zone are strained and thereafter subjected to a heat treatment.

36. The method of claim 32 , wherein the first zone is strained at a temperature of from about −50° C. to about 125° C.

37. The method of claim 32 , wherein the first zone is strained at a temperature that is at least about 10° C.

Assignees

• Kimberly Clark Co

Inventors

• Topolkaraev Vasily A
• Mceneany Ryan J
• Scholl Neil T
• Mleziva Mark M

Classifications

• B29L2007/002

  Panels; Plates; Sheets · CPC title

• B32B27/12 Primary

  next to a fibrous or filamentary layer · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• B29K2105/256

  Sheets, plates, blanks or films · CPC title

• C08L67/04

  Polyesters derived from hydroxycarboxylic acids, e.g. lactones (C08L67/06 takes precedence) · CPC title