EP0216622A2 — Microporous membrane laminate

Claim 1

Independent Claim 176 words

A method for manufacturing microporous membranes (10) comprising the steps of: A. mixing into a liquid vehicle a precursor material which is 1) rapidly polymerizable under ultraviolet or electron beam irradiation to a solid polymer, which is insoluble and nondispersible in the liquid vehicle such that when the polymers are formed it rapidly segregates from the liquid vehicle, and 2) selected from the group consisting of the organic monomers, the organic oligomers and mixtures thereof which are soluble in the liquid vehicle whereby upon said mixing there results a composition which is a liquid solution of said material in said liquid vehicle, said liquid vehicle being chemically inert relative to said material; B. forming said composition into a thin liquid layer; C. exposing the liquid layer to ultraviolet or electron beam irradiation to finally cure the liquid layer and, D. removing the liquid vehicle from the membrane, characterised in that the precursor material includes a hydrophobic monomer or monomers and/or a support material is applied into intimate contact with the liquid layer before final curing thereof.

Claim 2

Independent Claim 176 words

A method for manufacturing microporous membranes (10) comprising the steps of: A. mixing into a liquid vehicle a precursor material which is 1) rapidly polymerizable under ultraviolet or electron beam irradiation to a solid polymer, which is insoluble and nondispersible in the liquid vehicle such that when the polymers are formed it rapidly segregates from the liquid vehicle, and 2) selected from the group consisting of the organic monomers, the organic oligomers and mixtures thereof which are soluble in the liquid vehicle whereby upon said mixing there results a composition which is a liquid solution of said material in said liquid vehicle, said liquid vehicle being chemically inert relative to said material; B. forming said composition into a thin liquid layer; C. exposing the liquid layer to ultraviolet or electron beam irradiation to finally cure the liquid layer and, D. removing the liquid vehicle from the membrane, characterised in that the precursor material includes a hydrophobic monomer or monomers and/or a support material is applied into intimate contact with the liquid layer before final curing thereof.

Claim 3

Dependent Claim 17 words

A method as set forth in claim 1 wherein said hydrophobic monomer is 1,1,3,3-tetramethylbutylacrylamide (t-octylacrylamide or TOCTAM).

Claim 4

Dependent Claim 28 words

A method as set forth in claim 1 or 2 wherein said hydrophobic monomer comprises between 8 to 33% by weight of the polymerizable material in the formulation.

Claim 5

Dependent Claim 91 words

A method as set forth in claim 1 wherein said hydrophobic monomer is an acrylic perfluoromonomer of the formula where R F is a perfluoroalkyl radical, C k F 2k+1' where k is essentially 6 to 10, R is of the formula C m H 2m+1 where m = 2-4, and R' is hydrogen or methyl, providing hydrophobicity to the microporous film, or a perfluoroacrylic monomer of the structure R F - CH₂ - O - - CH = CH₂ where R F = C z F 2z+1 , and z=6-8.

Claim 6

Dependent Claim 24 words

A method as set forth in claim 4 including said perfluoromonomer as 3% to 25% by weight of said polymerizable material in said solution.

Claim 7

Independent Claim 66 words

A method as set forth in any preceeding claim wherein the support material (14) is applied into intimate contact with the liquid layer before final curing thereof and further including the step of exposing the thin liquid layer to electron beam or ultraviolet radiation to partially polymerize said precursor material, prior to applying the support material (14) into intimate contact with the original thin liquid layer.

Claim 8

Dependent Claim 21 words

A method as set forth in claim 6 wherein the further step is carried out in the presence of atmospheric oxygen.

Claim 9

Independent Claim 38 words

A method as set forth in any preceeding claim wherein said step of forming said composition into a thin layer is further defined as spreading said composition on to a support surface (16) such as a moving belt.

Claim 10

Independent Claim 125 words

A method as set forth in any preceeding claim wherein said oligomeric material is an acrylic polyester urethane of the formula R₁ - (R₂-R₃) n -R₂-R₁ where R₁ is the radical of an hydroxy terminated acrylate monomer such as hydroxyethylacrylate, hydroxypropylacrylate and 4-hydroxybutyl acrylate; R₂ is the dicarbamate or tricarbamate group resulting from the reaction of the isocyanate materials selected from the group consisting of di -and/or tri-aliphatic or aromatic isocyanates; R₃ being selected from the group of polyester polyols made from the condensation of adipic acid with each one of or a mixture of ethylene glycol, diethyleneglycol, butanediol, hexanediol, and neopentylglycol, R₃ having a number average molecular weight of 200 to 3000 and n equalling 0 to 4, or a mixture of such oligomers.

Claim 11

Dependent Claim 31 words

A method as set forth in claim 9 wherein the percent nitrogen associated with carbamate functionality of said oligomers is in the range of 1.5 ± 0.3% to 6.2 ± 0.3%.

Claim 12

Dependent Claim 31 words

A method as set forth in claim 9 wherein the formula is modified to wherein the structure of the poly functional acrylates results from using trifunctional polyol and trifunctional isocyanates respectively.

Claim 13

Independent Claim 27 words

A method as set forth in any preceeding claim further including the step of mixing a cross linking monomer with said precursor material in said liquid vehicle.

Claim 14

Dependent Claim 24 words

A method as set forth in claim 12 wherein said crosslinking monomer is a difunctional or trifunctional acrylate ester crosslinking monomer, or mixture thereof.

Claim 15

Dependent Claim 30 words

A method as set forth in claim 12 or 13 wherein said cross linking monomer comprises less than or equal to 50% (weight/weight) of the polymerizable material in the mixture.

Claim 16

Independent Claim 29 words

A method as set forth in any preceeding claim further including the step of mixing one or a combination of monofunctional monomers with precursor material in said liquid vehicle.

Claim 17

Dependent Claim 24 words

A method as set forth in claim 15 wherein said monomer is from the group of monofunctional acrylate esters acrylamides, n-vinylpyrrolidone and n-vinyl lactam.

Claim 18

Dependent Claim 26 words

A method as set forth in claim 16 wherein said monomer comprises less than or equal to 50% (weight/weight) of the polymerizable material in the mixture.

Claim 19

Independent Claim 61 words

A method as set forth in any preceeding claim wherein said liquid vehicle is from the group having the formula of CH₃ (CH₂) n COOR' where R' equals methyl, ethyl, or isopropyl, and n equals 6-16 or having the formula of, R"OCO(CH₂) n COOR" where n equals 3 to 8 and R" equals methyl, ethyl, isopropyl, butyl, isobutyl, octyl and isooctyl.

Claim 20

Dependent Claim 23 words

A method as set forth in claim 18 wherein said liquid vehicle further consists of butylcellosolve acetate in combination with said liquid vehicle.

Claim 21

Independent Claim 26 words

A method as set forth in any preceeding claim wherein the weight percent of said liquid vehicle in said mixture is from 40 to 80 percent.

Claim 22

Dependent Claim 29 words

A method as set forth in claim 20 further including the step of reducing the pore size of said membrane laminate by decreasing said weight percent of liquid vehicle.

Claim 23

Independent Claim 30 words

A method as set forth in any preceeding claim further including the step of adjusting the cloud point temperature of the mixture to alter the pore size of said membrane.

Claim 24

Independent Claim 23 words

A method as set forth in any preceeding claim further including the step of mixing surfactants with said oligomer in said liquid vehicle.

Claim 25

Independent Claim 20 words

A method as set forth in any preceeding claim wherein said support material (14) is a woven or nonwoven fabric.

Claim 26

Dependent Claim 25 words

A method as set forth in claim 24 wherein said nonwoven fabric consists essentially of nonwoven polyamide, polyester, cellulose derivative or corona discharge treated polypropylene.

Claim 27

Dependent Claim 36 words

A method as set forth in claim 8 wherein after applying the support material (14) said liquid layer is exposed to ultraviolet light which is passed through said support (14) to finally cure said liquid layer.

Claim 28

Dependent Claim 39 words

A method as set forth in claim 26 wherein said belt is made from a transparent release film made of silicone coated polypropylene or polyester, and said liquid layer is exposed to ultraviolet irradiation from below said moving belt.

Claim 29

Independent Claim 23 words

A method as set forth in any preceeding claim including the step of rolling said laminate (10) prior to removing said liquid vehicle.

Claim 30

Independent Claim 65 words

A method as set forth in any preceeding claim including the step of forming a first and second laminate (10,10'), applying said mixture of liquid vehicle and precursor between the polymerized liquid vehicle layers (14,14') of the first and second laminates (10,10') and exposing said mixture to ultraviolet or electron beam irradiation to finally cure the liquid layer and to form a multilayer composite laminate.

Claim 31

Dependent Claim 106 words

A membrane comprising a microporous polymerized layer (12) of a precursor material which forms a homogenous solution with a liquid vehicle and 1) is rapidly polymerizable under ultraviolet or electron beam irradiation to said polymerized material (12), which is insoluble and nondispersable in the liquid vehicle, and 2) is selected from the group consisting of the organic monomers, the organic oligomers and mixtures thereof which are soluble in the liquid vehicle, the liquid vehicle being inert relative to said precursor material, characterisd in that said precursor material includes a hydrophobic monomer or monomers and/or a support material (14) laminated directly to said microporous polymerised material (12).

Claim 32

Dependent Claim 106 words

A membrane comprising a microporous polymerized layer (12) of a precursor material which forms a homogenous solution with a liquid vehicle and 1) is rapidly polymerizable under ultraviolet or electron beam irradiation to said polymerized material (12), which is insoluble and nondispersable in the liquid vehicle, and 2) is selected from the group consisting of the organic monomers, the organic oligomers and mixtures thereof which are soluble in the liquid vehicle, the liquid vehicle being inert relative to said precursor material, characterisd in that said precursor material includes a hydrophobic monomer or monomers and/or a support material (14) laminated directly to said microporous polymerised material (12).

Claim 33

Dependent Claim 17 words

A membrane as set forth in claim 30 wherein said hydrophobic monomer is 1,1,3,3-tetramethylbutylacrylamide (t-octylacrylamide or TOCTAM).

Claim 34

Dependent Claim 28 words

A membrane as set forth in claim 31 including TOCTAM and said hydrophobic monomer comprises between 8% to 30% by weight of said polymerizable material in said solution.

Claim 35

Dependent Claim 92 words

A membrane as set forth in claim 32 wherein said hydrophobic monomer is an acrylic perfluoromonomer of the formula where R F is a perfluoroalkyl radical, C k F 2k+1 , where k is essentially 6 to 10, R is of the formula C m H 2m+1 where m = 2-4, and R' is hydrogen or methyl, providing hydrophobicity to the mocroporous film, or a perfluoroacrylic monomer of the structure R F - CH₂ - O - - CH = CH₂ where R F = C z F 2z+1 , and z=6-8.

Claim 36

Dependent Claim 23 words

A membrane as set forth in claim 33 including perfluoromonomer as 3% to 25% by weight of said polymerizable material in said solution.

Claim 37

Dependent Claim 121 words

A membrane as set forth in any of claims 30 to 34 wherein the oligomeric material is an acylic polyester urethane of the formula R₁ - (R₂-R₃) n -R₂-R₁ where R₁ is the radical of an hydroxy terminated acrylate monomer such as hydroxyethylacrylate, hydroxypropylacrylate and 4-hydroxybutylacrylate; R₂ is the dicarbamate or tricarbamate group resulting from the reaction of the isocyanate materials selected from the group consisting of di- and/or tri-aliphatic or aromatic isocyanates; and R₃ is selected from the group of polyester polyols made from the condensation of adipic acid with each one or a mixture of ethylene glycol, diethyleneglycol, butanediol, hexanediol, and neopentylglycol, R₃ having a number average molecular weight of 200 to 3000 and n equalling 0 to 4.

Claim 38

Dependent Claim 32 words

A membrane as set forth in claim 35 wherein the weight percent nitrogen associated with carbamate functionality of said oligomers is in the range of 1.5 ± 0.3% to 6.2 ± 0.3%.

Claim 39

Dependent Claim 33 words

A membrane as set forth in claim 35 or 36 wherein the formula is modified to wherein the structure of the poly functional acrylates results from using trifunctional polyol and trifunctional isocyanates respectively.

Claim 40

Dependent Claim 20 words

A membrane as set forth in any of claims 30 to 37 wherein said microporous material includes a crosslinking monomer.

Claim 41

Dependent Claim 25 words

A membrane as set forth in claim 38 wherein said crosslinking monomer is a difunctional or trifunctional acrylate ester crosslinking monomers or a mixture thereof.

Claim 42

Dependent Claim 32 words

A membrane as set forth in any of claim 30 to 39 wherein said microporous material includes a monofunctional monomer from the group of monofunctional acrylate estes, acrylamides, n-vinylpyrrolidone and n-vinyl lactam.

Claim 43

Dependent Claim 26 words

A membrane as set forth in claim 40 wherein said monomer comprises less than or equal to 50% (weight/weight) of the polymerizable material in the membrane.

Claim 44

Dependent Claim 21 words

A membrane as set forth in any of claims 30 to 41 wherein said support material (14) is a nonwoven fabric.

Claim 45

Dependent Claim 25 words

A membrane as set forth in claim 42 wherein said nonwoven fabric consists essentially of nonwoven polyamide, polyester, cellulosic derivative or corona discharge treated polypropylene.

Claim 46

Dependent Claim 33 words

A membrane as set forth in any of claims 30 to 42 wherein said laminate includes two inner layers (12,12') of said polymerized material and two outer layers (14,14') of said support material.

Claim 47

Dependent Claim 32 words

A membrane as set forth in any of claims 30 to 44 wherein said support material (14) has interstitial spaces, said polymerized material (12) being at least partially disposed within said spaces.

Claim 48

Dependent Claim 23 words

A membrane as set forth in any of claims 30 to 45 including a plurality of layers of said cured microporous material (12).

Claim 49

Dependent Claim 19 words

A membrane as set forth in claim 46 wherein each of said layers have different physical and chemical properties.

Microporous membrane laminate

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