Multilayer article of microporous and substantially nonporous materials

Claim 2

A multilayer article comprising material which is impervious to the passage of gas and bacteria fusion bonded in the absence of extrinsic intervening adhesive to microporous material comprising: (a) a matrix consisting essentially of essentially linear ultrahigh molecular weight polyolefin which is essentially linear ultrahigh molecular weight polyethylene having an intrinsic viscosity of at least about 18 deciliters/gram, essentially linear ultrahigh molecular weight polypropylene having an intrinsic viscosity of at least about 6 deciliters/gram, or a mixture thereof. (b) finely divided particulate substantially water-insoluble siliceous filler distributed throughout said matrix, said filler constituting from about 50 percent to about 90 percent by weight of said microporous material, and (c) a network of interconnecting pores communicating throughout said microporous material, said pores before fusion bonding constituting at least about 35 percent by volume of said microporous material.

Claim 3

The multilayer article of claim 1 wherein (a) said essentially linear ultrahigh molecular weight polyolefin is essentially linear ultrahigh molecular weight polyethylene having an intrinsic viscosity of at least about 18 deciliters/gram, (b) said siliceous filler is precipitated silica, and (c) said pores before fusion bonding constitute from about 35 percent to about 80 percent by volume of said microporous material.

Claim 4

The multilayer article of claim 2 wherein said material which is impervious to the passage of gas and bacteria is polyethylene.

Claim 5

The multilayer article of claim 3 wherein said polyethylene is heat sealed to said microporous material.

Claim 6

A multilayer article comprising at least one layer of substantially nonporous material fusion bonded in the absence of extrinsic intervening adhesive to at least one layer of microporous material comprising: (a) a matrix consisting essentially of essentially linear ultrahigh molecular weight polyolefin which is essentially linear ultrahigh molecular weight polyethylene having an intrinsic viscosity of at least about 18 deciliters/gram, essentially linear ultrahigh molecular weight polypropylene having an intrinsic viscosity of at least about 6 deciliters/gram, or a mixture thereof, (b) finely divided particulate substantially water-insoluble filler, of which at least about 50 percent by weight is siliceous, distributed throughout said matrix, said filler constituting from about 50 percent to about 90 percent by weight of said microporous material, and (c) a network of interconnecting pores communicating throughout said microporous material, said pores before fusion bonding constituting at least about 35 percent by volume of said microporous material.

Claim 7

A multilayer article comprising at least one layer of substantially nonporous material fusion bonded in the absence of extrinsic intervening adhesive to at least one layer of microporous material comprising: (a) a matrix consisting essentially of essentially linear ultrahigh molecular weight polyolefin which is essentially linear ultrahigh molecular weight polyethylene having an intrinsic viscosity of at least about 18 deciliters/gram, essentially linear ultrahigh molecular weight polypropylene having an intrinsic viscosity of at least about 6 deciliters/gram, or a mixture thereof, (b) finely divided particulate substantially water-insoluble filler, of which at least about 50 percent by weight is siliceous, distributed throughout said matrix, said filler constituting from about 50 percent to about 90 percent by weight of said microporous material, and (c) a network of interconnecting pores communicating throughout said microporous material, said pores before fusion bonding constituting at least about 35 percent by volume of said microporous material.

Claim 8

The multilayer article of claim 5 wherein said microporous material has a thickness in the range of from about 0.03 to about 4 millimeters.

Claim 9

The multilayer article of claim 5 wherein said substantially nonporous material is thermoplastic polymeric sheet or film.

Claim 10

The multilayer article of claim 5 wherein said substantially nonporous material is metalized thermoplastic polymeric sheet or film.

Claim 11

The multilayer article of claim 5 wherein said substantially nonporous material is thermoset polymeric sheet or film.

Claim 12

The multilayer article of claim 5 wherein said substantially nonporous material is elastomeric sheet or film.

Claim 13

The multilayer article of claim 5 wherein said substantially nonporous material is metal sheet or foil.

Claim 14

The multilayer article of claim 5 wherein said essentially linear ultrahigh molecular weight polyolefin is essentially linear ultrahigh molecular weight polyethylene having an intrinsic viscosity of at least about 18 deciliters/gram.

Claim 15

The multilayer article of claim 12 wherein said ultrahigh molecular weight polyethylene has an intrinsic viscosity in the range of from about 18 to about 39 deciliters/gram.

Claim 16

The multilayer article of claim 12 wherein said filler constitutes from about 50 percent to about 85 percent by weight of said microporous material.

Claim 17

The multilayer article of claim 12 wherein at least about 85 percent by weight of said filler is siliceous.

Claim 18

The multilayer article of claim 12 wherein all of said filler is siliceous.

Claim 19

The multilayer article of claim 12 wherein said siliceous filler is silica.

Claim 20

The multilayer article of claim 12 wherein said siliceous filler is precipitated silica.

Claim 21

The multilayer article of claim 18 wherein said precipitated silica has an average ultimate particle size of less than about 0.1 micrometer.

Claim 22

The multilayer article of claim 12 wherein the volume average diameter of said pores as determined by mercury porosimetry is in the range of from about 0.02 to about 50 micrometers.

Claim 23

The multilayer article of claim 12 wherein said pores constitute from at least about 35 percent to about 95 percent by volume of said microporous material.

Claim 24

The multilayer article of claim 12 wherein said pores constitute from about 35 percent to about 80 percent by volume of said microporous material.

Claim 25

The multilayer article of claim 12 wherein said pores constitute from more than 80 percent to about 95 percent by volume of said microporous material.

Claim 26

The multilayer article of claim 5 wherein said layer of microporous material is heat sealed to said layer of substantially nonporous material.

Claim 27

The multilayer article of claim 5 wherein said layer of microporous material is discontinuously fusion bonded to said layer of substantially nonporous material.

Claim 28

The multilayer article of claim 5 wherein said layer of microporous material is essentially continuously fusion bonded to said layer of substantially nonporous material.

Claim 29

The multilayer article of claim 5 wherein other thermoplastic organic polymer is present in said matrix and wherein at least about 50 percent by weight of said matrix is said essentially linear ultrahigh molecular weight polyolefin.

Claim 30

The multilayer article of claim 27 wherein said other thermoplastic organic polymer is polypropylene.

Claim 31

The multilayer article of claim 27 wherein said other thermoplastic organic polymer is high density polyethylene.

Claim 32

The multilayer article of claim 5 wherein other thermoplastic organic polymer is present in said matrix and wherein at least about 70 percent by weight of said matrix is said essentially linear ultrahigh molecular weight polyolefin.

Claim 33

The multilayer article of claim 5 wherein other thermoplastic organic polymer is substantially absent from said matrix.