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US 6,111,163 AGranted
Elastomeric film and method for making the same
AssigneeKimberly-Clark Worldwide, Inc.
InventorsAnn L. McCormack, William B. Haffner
Life of this patent
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Abstract
The present invention relates to a breathable, oriented microporous elastomeric film. The present invention also relates to a process for forming the breathable film including the step of stretching a filled film to produce a microporous film layer.
Claims18
A breathable film comprising:
- An oriented microporous relaxed unbiased film layer(10c) comprising an elastomeric polymer resin and at least 30% by weight of a filler having a particle size that contributes to pore formation,
- the relaxed unbiased film layer formed from an unstretched filled film (10a) having an original length a stretched length (10b), said relaxed unbiased film layer including a permanent elongation of at least about 1.5 times the original length,
- and said relaxed unbiased film layer (10c) capable of having a room-temperature biased length that is at least about one and a half times said relaxed unbiased film layer length and a release length, upon release of a biasing force of no more than one and one quarter of the relaxed unbiased film layer length, having a water vapor transmission rate of at least about 1,000 g/m.sup.2 -24 hrs,
- wherein said elastomeric polymer includes at least one of a) ethylene-propylene elastomer blends, b) ethylene copolymers, c)block copolymers including styrene, d) terpolymers of ethylene and propylene, e)molecular blends of at least two polymers of propylenes or polymers of propylene with ethylene,f) ethylene vinyl acetate, g) ethylene-normal butyl acrylate, or h) ethylene methyl acrylate.
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A process for forming a breathable elastic film capable of being elongated to a stretched length at least one and a half times its starting length and recovering at least half of its elongation, the process comprising:
- a) providing an unstretched filled film layer comprising at least 30% by weight of a filler having a particle size that contributes to pore formation and an elastomeric polymeric material having a first length,
- b) stretching said filled film layer to a second length that is at least about two times said first length so as to create a stretched filled microporous film layer,
- c) relaxing said stretched filled microporous film layer of step b so as to produce a film with a permanent elongation of at least one and a half times said first length.
A breathable film comprising:
- an oriented microporous relaxed unbiased film layer (10c) including an elastomeric polymer resin and at least 30% by weight of a filler having a particle size that contributes to pore formation and coated with a fatty acid,
- the relaxed unbiased film layer formed from an unstretched filled film (10a) having an original length a stretched length (10b), said relaxed unbiased film layer including a permanent elongation of at least about 1.5 times the original length,
- and said relaxed unbiased film layer (10c) capable of having a room-temperature biased length that is at least about one and a half times said relaxed unbiased film layer length and a release length, upon release of a biasing force of no more than one and one quarter of the relaxed unbiased film layer length, having a water vapor transmission rate of at least about 1,000 g/m.sup.2 -24 hrs, and
- wherein said elastomeric polymer includes at least one of a) ethylene-propylene elastomer blends, b) ethylene copolymers, c)block copolymers including styrene, d) terpolymers of ethylene and propylene, e)molecular blends of at least two polymers of propylenes or polymers of propylene with ethylene,f) ethylene vinyl acetate, g) ethylene-normal butyl acrylate, or h) ethylene methyl acrylate.
1 more element
A breathable film comprising:
- An oriented microporous relaxed unbiased film layer (10c) comprising an elastomeric polymer resin and at least 30% by weight of a filler having a particle size that contributes to pore formation and coated with a fatty acid,
- the relaxed unbiased film layer formed from an unstretched filled film (10a) having an original length a stretched length (10b), said relaxed unbiased film layer including a permanent elongation of about 1.5 times the original length,
- and said relaxed unbiased film layer (10c) capable of having a room-temperature biased length that is at least about one and a half times said relaxed unbiased film layer length and a release length, upon release of a biasing force of no more than one and one quarter of the relaxed unbiased film layer length, having a water vapor transmission rate of at least about 1,000 g/m.sup.2 -24 hrs, and
- wherein said elastomeric polymer includes at least one of a) ethylene-propylene elastomer blends, b) ethylene copolymers, c)block copolymers including styrene, d) terpolymers of ethylene and propylene, e)molecular blends of at least two polymers of propylenes or polymers of propylene with ethylene,f) ethylene vinyl acetate, g) ethylene-normal butyl acrylate, or h) ethylene methyl acrylate.
1 more element
A breathable film comprising:
- An oriented microporous relaxed unbiased film layer (10c) comprising an elastomeric polymer resin and at least 30% by weight of a filler having a particle size that contributes to pore formation,
- the relaxed unbiased film layer formed from an unstretched filled film (10a) having an original length a stretched length (10b), said relaxed unbiased film layer including a permanent elongation of about 1.5 times the original length,
- and said relaxed unbiased film layer (10c) capable of having a room-temperature biased length that is at least about one and a half times said relaxed unbiased film layer length and a release length, upon release of a biasing force of no more than one and one quarter of the relaxed unbiased film layer length, having a water vapor transmission rate of at least about 1,000 g/m.sup.2 -24 hrs,
- wherein said elastomeric polymer includes at least one of a) ethylene-propylene elastomer blends, b) ethylene copolymers, c)block copolymers including styrene, d) terpolymers of ethylene and propylene, e)molecular blends of at least two polymers of propylenes or polymers of propylene with ethylene,f) ethylene vinyl acetate, g) ethylene-normal butyl acrylate, or h) ethylene methyl acrylate.
1 more element
A breathable film comprising:
- An oriented microporous relaxed unbiased film layer (10c) comprising an elastomeric polymer resin and at least 30% by weight of a filler having a particle size that contributes to pore formation,
- the relaxed unbiased film layer formed from an unstretched filled film (10a) having an original length a stretched length (10b), said relaxed unbiased film layer including a permanent elongation of at least about 1.5 times the original length,
- and said relaxed unbiased film layer (10c) capable of having a room-temperature biased length that is at least about one and a half times said relaxed unbiased film layer length and a release length, upon release of a biasing force of no more than one and one quarter of the relaxed unbiased film layer length, having a water vapor transmission rate of at least about 1,000 g/m.sup.2 -24 hrs,
- wherein said elastomeric polymer comprises a block copolymer including styrene and at least one of ethylene, butylene and isoprene.
1 more element
A breathable film comprising:
- An oriented microporous relaxed unbiased film layer (10c) comprising an elastomeric polymer resin and at least 30% by weight of a filler having a particle size that contributes to pore formation,
- the relaxed unbiased film layer formed from an unstretched filled film (10a) having an original length a stretched length (10b), said relaxed unbiased film layer including a permanent elongation of at least about 1.5 times the original length,
- and said relaxed unbiased film layer (10c) capable of having a room-temperature biased length that is at least about one and a half times said relaxed unbiased film layer length and a release length, upon release of a biasing force of no more than one and one quarter of the relaxed unbiased film layer length, having a water vapor transmission rate of at least about 1,000 g/m.sup.2 -24 hrs,
- wherein said elastomeric polymer includes a metallocene-catalyzed elastomer.
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Dependencies are inferred from the claim text.