Porous membrane having hydrophilic surface and process

Claim 2

A composite porous thermoplastic membrane which comprises a porous membrane substrate having an average pore size between about 0.001 and 10 microns formed of a first polymer, said substrate being directly coated on its entire surface with a cross-linked second polymer formed from a monomer polymerized in situ with a free radical initiator and cross-linked in situ on said substrate, said composite porous membrane having essentially the same porous configuration as said porous membrane substrate.

Claim 3

The composite porous membrane of claim 1 wherein the first polymer is a halogenated hydrocarbon polymer.

Claim 4

The composite porous membrane of claim 1 wherein the first polymer is a fluorinated hydrocarbon polymer.

Claim 5

The composite porous membrane of claim 1 wherein the first polymer is polyvinylidene fluoride.

Claim 6

The composite porous membrane of claim 1 wherein the first polymer is polytetrafluoroethylene.

Claim 7

The composite porous membrane of claim 1 wherein the first polymer is a hydrocarbon polymer.

Claim 8

The composite porous membrane of claim 1 wherein the first polymer is a polysulfone polymer.

Claim 9

The composite porous membrane of claim 1 wherein the first polymer is a polyethersulfone polymer.

Claim 10

The composite porous membrane of any one of claims 1, 2, 3, 4, 5, 6, 7 or 8 wherein said second polymer is formed from an hydroxyalkyl acrylate or methacrylate.

Claim 11

The composite porous membrane of any one of claims 1, 2, 3, 4, 5, 6, 7 or 8 wherein the second polymer is formed from a hydroxyalkyl acrylate or methacrylate which is cross-linked with propylene glycol diacrylate.

Claim 12

The composite porous membrane of any one of claims 1, 2, 3, 4, 5, 6, 7 and 8 wherein the second polymer is formed from a hydroxyalkyl acrylate or methacrylate which is cross-linked with tetraethylene glycol diacrylate.

Claim 13

The composite porous membrane of any one of claims 1, 2, 3, 4, 5, 6, 7 or 8 wherein the second polymer is formed from an acrylamide or methacrylamide which is cross-linked with a difunctional acrylamide or methacrylamide.

Claim 14

The composite porous membrane of any one of claims 1, 2, 3, 4, 5, 6, 7 or 8 wherein the second polymer is formed from a polar-substituted acrylate or methacrylate which is cross-linked with a difunctional acrylate or methacrylate.

Claim 15

The composite porous membrane of any one of claims 1, 2, 3, 4, 5, 6, 7 or 8 wherein the second polymer is formed from a functionally-substituted acrylate or methacrylate which is cross-linked with a difunctional acrylate or methacrylate.

Claim 16

The process for forming a composite porous membrane formed from a porous membrane substrate having an average pore size between about 0.001 and 10 microns formed of a first polymer, said substrate being directly coated over its entire surface with a crosslinked second polymer, said composite porous membrane having essentially the same porous configuration as said porous membrane substrate which comprises: (a) washing said porous membrane substrate to wet the surfaces of the pores in said porous membrane; and (b) contacting said porous membrane from step (a) with a solution of a monomer of said second polymer, a cross-linking agent for said monomer and a polymerization initiator for said monomer under conditions to polymerize said monomer and to cross-link said second polymer in situ over the entire surface of said first polymer under conditions to avoid plugging of said pores.

Claim 17

The process for forming a composite porous membrane formed from a porous membrane substrate having an average pore size between about 0.001 and 10 microns formed of a first polymer, said substrate being directly coated over its entire surface with a crosslinked second polymer, said composite porous membrane having essentially the same porous configuration as said porous membrane substrate which comprises: (a) washing said porous membrane substrate to wet the surfaces of the pores in said porous membrane; and (b) contacting said porous membrane from step (a) with a solution of a monomer of said second polymer, a cross-linking agent for said monomer and a polymerization initiator for said monomer under conditions to polymerize said monomer and to cross-link said second polymer in situ over the entire surface of said first polymer under conditions to avoid plugging of said pores.

Claim 18

The process of claim 15 wherein said first polymer is a halogenated hydrocarbon polymer.

Claim 19

The process of claim 15 wherein said first polymer is a fluorinated hydrocarbon polymer.

Claim 20

The process of claim 15 wherein said first polymer is polyvinylidene fluoride.

Claim 21

The process of claim 15 wherein said first polymer is poly(tetrafluorothylene).

Claim 22

The process of claim 15 wherein said first polymer is a hydrocarbon polymer.

Claim 23

The process of claim 15 wherein said first polymer is a polysulfone polymer.

Claim 24

The process of claim 15 wherein said first polymer is a polyethersulfone polymer.

Claim 25

The process of claim 15 wherein said first polymer is a polycarbonate polymer.

Claim 26

The process of any of claims 15, 16, 17, 18, 19, 20, 21, 22 or 23 wherein said monomer is a hydroxyalkyl acrylate or methacrylate.

Claim 27

The process of any of claims 15, 16, 17, 18, 19, 20, 21, 22 or 23 wherein said monomer is an acrylamide or methacrylamide.

Claim 28

The process of any of claims 15, 16, 17, 18, 19, 20, 21, 22 or 23 wherein said monomer is a polar-substituted acrylate or methacrylate.

Claim 29

The process of any of claims 15, 16, 17, 18, 19, 20, 21, 22 or 23 wherein said monomer is functionally-substituted acrylate or methacrylate.

Claim 30

The process of any of claims 15, 16, 17, 18, 19, 20, 21, 22 or 23 wherein said monomer is a hydroxyalkyl acrylate and said cross-linking agent is a difunctional acrylate or methacrylate.

Claim 31

The process of any of claims 15, 16, 17, 18, 19, 20, 21, 22 or 23 wherein said cross-linking agent is a difunctional acrylate or methacrylate.

Claim 32

The process of any claims 15, 16, 17, 18, 19, 20, 21, 22 or 23 wherein said cross-linking agent is a multifunctional acrylate or methacrylate.

Claim 33

The process of any of claims 15, 16, 17, 18, 19, 20, 21, 22 or 23 wherein said cross-linking agent is a difunctional acrylamide or methacrylamide.

Claim 34

The process of claim 15 wherein said polymerization initiator is a persulfate compound.

Claim 35

The process of claim 15 wherein said polymerization initiator is ammonium persulfate.

Claim 36

The process of claim 15 wherein said polymerization initiator is an azo compound.

Claim 37

The process of any of claim 15 wherein said polymerization initiator is an organic peroxy compound.

Claim 38

The process of any of claim 15 wherein said monomer is a hydroxyalkyl acrylate or methacrylate, said cross-linking agent is tetraethylene glycol diacrylate, and said polymerization initiator is ammonium persulfate.

Claim 39

The composite porous product of any of claim 1, 2, 3, 4, 5, 6, 7 or 8 wherein the second polymer is formed from a polar substituted acrylate or methacrylate.

Claim 40

The composite porous product of any one of claims 1, 2, 3, 4, 5, 6, 7 or 8 wherein the second polymer is formed from a multifunctional acrylate or methacrylate.