Polyolefin Material having a Low Density

Patent metadata

Field	Value
Publication number	US-2016115291-A1
Application number	US-201414895054-A
Country	US
Kind code	A1
Filing date	Jun 6, 2014
Priority date	Jun 12, 2013
Publication date	Apr 28, 2016
Grant date	—

Abstract

A polyolefin material that is formed by solid state drawing of a thermoplastic composition containing a continuous phase that includes a polyolefin matrix polymer and nanoinclusion additive is provided. The nanoinclusion additive is dispersed within the continuous phase as discrete nano-scale phase domains. When drawn, the nano-scale phase domains are able to interact with the matrix in a unique manner to create a network of nanopores.

First claim

1 - 41 . (canceled)

42 . A polyolefin material that is formed by drawing of a thermoplastic composition, wherein the thermoplastic composition contains a continuous phase that includes a polyolefin matrix polymer and a nanoinclusion additive dispersed within the continuous phase in the form of discrete domains, wherein a porous network is defined in the composition that includes a plurality of nanopores having an average cross-sectional dimension of about 800 nanometers or less, the composition having a density of about 0.90 g/cm 3 or less.

43 . The polyolefin material of claim 42 , wherein the nanopores have an average cross-sectional dimension of from about 5 to about 700 nanometers.

44 . The polyolefin material of claim 42 , wherein nanopores have an average axial dimension of from about 100 to about 5000 nanometers.

45 . The polyolefin material of claim 42 , wherein the polyolefin matrix polymer has a melt flow rate of from about 0.5 to about 80 grams per 10 minutes as determined at a load of 2160 grams and at 230° C. in accordance with ASTM D1238.

46 . The polyolefin material of claim 42 , wherein the polyolefin matrix polymer is a propylene homopolymer, propylene/α-olefin copolymer, ethylene/α-olefin copolymer, or a combination thereof.

47 . The polyolefin material of claim 42 , wherein the polyolefin matrix polymer is a substantially isotactic polypropylene homopolymer or a copolymer containing at least about 90% by weight propylene.

48 . The polyolefin material of claim 42 , wherein the continuous phase constitutes from about 60 wt. % to about 99 wt. % of the thermoplastic composition.

49 . The polyolefin material of claim 42 , wherein the nanoinclusion additive is a polymer having a nonpolar component and a polar component.

50 . The polyolefin material of claim 49 , wherein the polymer is a functionalized polyolefin.

51 . The polyolefin material of claim 50 , wherein the functionalized polyolefin is a polyepoxide.

52 . The polyolefin material of claim 49 , wherein the nanoinclusion additive has melt flow rate of from about 0.1 to about 100 grams per 10 minutes, determined at a load of 2160 grams and at a temperature at least about 40° C. above the melting temperature in accordance with ASTM D1238.

53 . The polyolefin material of claim 49 , wherein the ratio of the melt flow rate of the polyolefin to the melt flow rate of the nanoinclusion additive is from about 0.2 to about 8.

54 . The polyolefin material of claim 42 , wherein the nanoinclusion additive is in the form of nano-scale domains, wherein the nano-scale domains have an average cross-sectional dimension of from about 1 nanometer to about 1000 nanometers.

55 . The polyolefin material of claim 42 , 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.

56 . The polyolefin material of claim 42 , wherein the composition further comprises a microinclusion additive dispersed within the continuous phase in the form of discrete domains.

57 . The polyolefin material of claim 56 , wherein the microinclusion additive is a polymer.

58 . The polyolefin material of claim 57 , wherein the polymer of the microinclusion additive is polylactic acid.

59 . The polyolefin material of claim 57 , wherein the polymer of the microinclusion additive has a glass transition temperature of about 0° C. or more.

60 . The polyolefin material of claim 57 , wherein the microinclusion additive has a melt flow rate of from about 5 to about 200 grams per 10 minutes, determined at a load of 2160 grams and at a temperature of 210° C.

61 . The polyolefin material of claim 57 , wherein the ratio of the melt flow rate of the microinclusion additive to the melt flow rate of the polyolefin matrix polymer is from about 0.5 to about 10.

62 . The polyolefin material of claim 57 , wherein the ratio of the Young's modulus elasticity of the polyolefin matrix polymer to the Young's modulus of elasticity of the microinclusion additive is from about 1 to about 250.

63 . The polyolefin material of claim 57 , wherein the microinclusion additive is in the form of micro-scale domains having an average axial dimension of from about 1 micrometer to about 400 micrometers.

64 . The polyolefin material of claim 57 , wherein the microinclusion additive constitutes from about 1 wt. % to about 30 wt. % of the composition, based on the weight of the continuous phase.

65 . The polyolefin material of claim 42 , wherein the thermoplastic composition further comprises an interphase modifier.

66 . The polyolefin material of claim 42 , wherein the porous network further includes micropores.

67 . The polyolefin material of claim 42 , wherein the porous network is distributed in a substantially homogeneous fashion throughout the composition.

68 . The polyolefin material of claim 42 , wherein the nanopores are distributed in generally parallel columns.

69 . The polyolefin material of claim 42 , wherein the total pore volume of the polyolefin material is from about 15% to about 80% per cubic centimeter.

70 . The polyolefin material of claim 42 , wherein nanopores constitute about 20 vol. % or more of the total pore volume of the polyolefin material.

71 . The polyolefin material of claim 42 , wherein the thermoplastic composition has a density of about 0.85 g/cm 3 or less.

72 . The polyolefin material of claim 42 , wherein the thermoplastic composition is generally free of blowing agents.

73 . The polyolefin material of claim 42 , wherein the thermoplastic composition is generally free of pore-initiating inorganic oxide fillers.

74 . An absorbent article comprising a polyolefin material that is formed by drawing of a thermoplastic composition, wherein the thermoplastic composition contains a continuous phase that includes a polyolefin matrix polymer and a nanoinclusion additive dispersed within the continuous phase in the form of discrete domains, wherein a porous network is defined in the composition that includes a plurality of nanopores having an average cross-sectional dimension of about 800 nanometers or less, the composition having a density of about 0.90 g/cm 3 or less, wherein the absorbent article includes a substantially liquid-impermeable layer, liquid-permeable layer, and an absorbent core.

75 . The absorbent article of claim 74 , wherein the substantially liquid-impermeable layer includes the polyolefin material.

76 . The absorbent article of claim 75 , wherein the substantially liquid-impermeable layer includes a nonwoven web material laminated to a film, and wherein the film includes the polyolefin material.

77 . A method for forming a polyolefin material, the method comprising:
forming a thermoplastic composition that contains a continuous phase that includes a polyolefin matrix polymer and a nanoinclusion additive dispersed within the continuous phase in the form of discrete domains; and solid state drawing the thermoplastic composition, wherein a porous network is defined in the composition that includes a plurality of nanopores having an average cross-sectional dimension of about 800 nanometers or less, the composition having a

Assignees

• Kimberly Clark Co

Inventors

• Topolkaraev Vasily A
• Mceneany Ryan J
• Carrillo Antonio J

Classifications

• C08J2201/02

  characterised by mechanical pre- or post-treatments · CPC title

• C08J9/0061 Primary

  characterized by the use of several polymeric components · CPC title

• C08L23/0815

  with aliphatic 1-olefins containing one carbon-to-carbon double bond · CPC title

• B32B3/26

  characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids {(foam layer B32B5/18; layer of synthetic resin characterised by fillers that create voids or cavities B32B27/205); characterised by an apertured layer} · CPC title

• B32B2307/7265

  Non-permeable · CPC title