US4833026A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Breathable, waterproof sheet materials and methods for making the same
Assignee: 3M Co
•
Filing: 1987-10-08
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Granted: 1989-05-23
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Expires: 2007-10-08
Abstract
Abstract The present invention relates to breathable, waterproof sheet materials comprising a microporous polymeric film and a hydrophilic filler material infiltrated into the pores of the film, and to methods for making such sheet materials. In the methods of the present invention, the liquid hydrophilic material or precursor thereof is infiltrated into the pores of the microporous film after the film has been stretched in the lengthwise direction, but before the film is stretched in the transverse direction. By coating the microporous film prior to the transverse stretching step, superior waterproof sheet materials are obtained.
Inventors
- 👤 William L. Kausch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:34
CPC Classifications
C; C08; C08J; C08J9/00; B; B29; B29C; B29C55/00; B29C55/02; B29C55/023; B29C55/026; C08J5/00; C08J5/18; C08J7/00; C08J7/04; C08J7/0427; C08J7/056; B29K; B29K2023/00; B29K2223/00; C08J2475/00; Y; Y10; Y10S; Y10S428/00; Y10S428/91; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249978
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
262 words
A unitary sheet material made according to a method comprising the steps of: preparing a sheet of polymeric material, said preparing step comprising: melt blending to form a solution comprising a crystallizable thermoplastic polymer and a compound with which said thermoplastic polymer is miscible and in which said thermoplastic polymer will dissolve at the melting temperature of said thermoplastic polymer but which will phase separate on cooling to a temperature at or below the crystallization temperature of said thermoplastic polymer; forming a sheet from the melt blended solution; and cooling said sheet to a temperature at which said thermoplastic polymer crystallizes to cause phase separation to occur between said compound and said polymer, thereby providing said sheet with an aggregate of a first phase comprising particles of crystallized thermoplastic polymer in a second phase comprising said compound with adjacent thermoplastic polymer particles being distinct but having a plurality of zones of continuity; stretching said polymeric sheet in a first direction so as to render said sheet more microporous; coating said polymeric sheet, after said polymeric sheet has been stretched in the first direction, with a liquid filler material which is capable of infiltrating the micropores of said polymeric sheet; stretching said coated polymeric sheet, after said coating step, in a second direction so as to render said polymeric sheet more microporous, said stretching of said polymeric sheet in the second direction serving to enhance infiltration of said liquid filler material into the micropores of said polymeric sheet; and converting said liquid filler material from a liquid state to a relatively solid state.
Claim 2
Dependent Claim
262 words
A unitary sheet material made according to a method comprising the steps of: preparing a sheet of polymeric material, said preparing step comprising: melt blending to form a solution comprising a crystallizable thermoplastic polymer and a compound with which said thermoplastic polymer is miscible and in which said thermoplastic polymer will dissolve at the melting temperature of said thermoplastic polymer but which will phase separate on cooling to a temperature at or below the crystallization temperature of said thermoplastic polymer; forming a sheet from the melt blended solution; and cooling said sheet to a temperature at which said thermoplastic polymer crystallizes to cause phase separation to occur between said compound and said polymer, thereby providing said sheet with an aggregate of a first phase comprising particles of crystallized thermoplastic polymer in a second phase comprising said compound with adjacent thermoplastic polymer particles being distinct but having a plurality of zones of continuity; stretching said polymeric sheet in a first direction so as to render said sheet more microporous; coating said polymeric sheet, after said polymeric sheet has been stretched in the first direction, with a liquid filler material which is capable of infiltrating the micropores of said polymeric sheet; stretching said coated polymeric sheet, after said coating step, in a second direction so as to render said polymeric sheet more microporous, said stretching of said polymeric sheet in the second direction serving to enhance infiltration of said liquid filler material into the micropores of said polymeric sheet; and converting said liquid filler material from a liquid state to a relatively solid state.
Claim 3
Independent Claim
271 words
A method of making a unitary sheet material from a polymeric material and a filler material, the method comprising the steps of: preparing a sheet of polymeric material, said preparing step comprising: melt blending to form a solution comprising a crystallizable thermoplastic polymer and a compound with which said thermoplastic polymer is miscible and in which said thermoplastic polymer will dissolve at the melting temperature of said thermoplastic polymer but which will phase separate on cooling to a temperature at or below the crystallization temperature of said thermoplastic polymer; forming a sheet from the melt blended solution; and cooling said sheet to a temperature at which said thermoplastic polymer crystallizes to cause phase separation to occur between said compound and said polymer, thereby providing said sheet with an aggregate of a first phase comprising particles of crystallized thermoplastic polymer in a second phase comprising said compound with adjacent thermoplastic polymer particles being distinct but having a plurality of zones of continuity; stretching said polymeric sheet in a first direction so as to render said sheet more microporous; coating said polymeric sheet, after said polymeric sheet has been stretched in the first direction, with a liquid filler material which is capable of infiltrating the micropores of said polymeric sheet; stretching said coated polymeric sheet, after said coating step, in a second direction so as to render said polymeric sheet more microporous, said stretching of said polymeric sheet in the second direction serving to enhance infiltration of said liquid filler material into the micropores of said polymeric sheet; and converting said liquid filler material from a liquid state to a relatively solid state.
Claim 4
Independent Claim
271 words
A method of making a unitary sheet material from a polymeric material and a filler material, the method comprising the steps of: preparing a sheet of polymeric material, said preparing step comprising: melt blending to form a solution comprising a crystallizable thermoplastic polymer and a compound with which said thermoplastic polymer is miscible and in which said thermoplastic polymer will dissolve at the melting temperature of said thermoplastic polymer but which will phase separate on cooling to a temperature at or below the crystallization temperature of said thermoplastic polymer; forming a sheet from the melt blended solution; and cooling said sheet to a temperature at which said thermoplastic polymer crystallizes to cause phase separation to occur between said compound and said polymer, thereby providing said sheet with an aggregate of a first phase comprising particles of crystallized thermoplastic polymer in a second phase comprising said compound with adjacent thermoplastic polymer particles being distinct but having a plurality of zones of continuity; stretching said polymeric sheet in a first direction so as to render said sheet more microporous; coating said polymeric sheet, after said polymeric sheet has been stretched in the first direction, with a liquid filler material which is capable of infiltrating the micropores of said polymeric sheet; stretching said coated polymeric sheet, after said coating step, in a second direction so as to render said polymeric sheet more microporous, said stretching of said polymeric sheet in the second direction serving to enhance infiltration of said liquid filler material into the micropores of said polymeric sheet; and converting said liquid filler material from a liquid state to a relatively solid state.
Claim 5
Dependent Claim
13 words
A method as defined in claim 2 wherein said polymer comprises a polyolefin.
Claim 6
Dependent Claim
12 words
A method as defined in claim 3 wherein said polymer comprises polyethylene.
Claim 7
Dependent Claim
19 words
A method as defined in claim 1 wherein said compound is removed from said sheet after said cooling step.
Claim 8
Dependent Claim
15 words
A method as defined in claim 5 wherein said compound is removed by solvent extraction.
Claim 9
Dependent Claim
21 words
A method as defined in claim 1 wherein said polymeric sheet is stretch about 600% or less in the first direction.
Claim 10
Dependent Claim
29 words
A method as defined in claim 1 wherein said polymeric sheet has a thickness of from about 25 micrometers to about 150 micrometers after stretching in the first direction.
Claim 11
Dependent Claim
29 words
A method as defined in claim 1 wherein said liquid filler material is a precursor of a solid hydrophilic material which is water vapor permeable and liquid water impermeable.
Claim 12
Dependent Claim
18 words
A method as defined in claim 9 wherein said hydrophilic material comprises a polyurethane having a polyoxyethylene backbone.
Claim 13
Dependent Claim
22 words
A method as defined in claim 9 wherein said precursor has a viscosity of from about 1 centipoise to about 500 centipoise.
Claim 14
Dependent Claim
19 words
A method as defined in claim 1 wherein said liquid filler material is gravure coated onto said polymeric sheet.
Claim 15
Dependent Claim
27 words
A method as defined in claim 12 wherein said liquid filler material is gravure coated at a pressure of from about 10 psi to about 100 psi.
Claim 16
Dependent Claim
35 words
A method as defined in claim 1 wherein the weight of said liquid filler material applied during said coating step represents from about 50% to about 600% of the weight of the uncoated polymeric sheet.
Claim 17
Dependent Claim
49 words
A method as defined in claim 1 wherein said liquid filler material is solvent coated onto said polymeric sheet and further comprising the step of heating said coated polymeric sheet before stretching in the second direction so as to substantially evaporate the solvent away from the liquid filler material.
Claim 18
Dependent Claim
47 words
A method as defined in claim 15 wherein said liquid filler material is curable and wherein said heating step is done at a temperature and for a time sufficient to evaporate the solvent while avoiding complete curing of said filler material before stretching in the second direction.
Claim 19
Dependent Claim
49 words
A method as defined in claim 15 wherein said liquid filler material is a precursor of a polyurethane and wherein said heating step is done at a temperature of from about 20° C. to about 150° C. for a period of from about 10 seconds to about 60 seconds.
Claim 20
Dependent Claim
36 words
A method as defined in claim 17 wherein said heating step is done at a temperature of from about 75° C. to about 110° C. for a period of about 20 seconds to about 40 seconds.
Claim 21
Dependent Claim
44 words
A method as defined in claim 1 wherein during stretching in the second direction said coated polymeric sheet is heated to a temperature of from about 35° C. to about 95° C. for a period of from about 10 seconds to about 60 seconds.
Claim 22
Dependent Claim
22 words
A method as defined in claim 1 wherein said coated polymeric sheet is stretched about 600% or less in the second direction.
Claim 23
Dependent Claim
56 words
A method as defined in claim 1 wherein said liquid filler material is curable into said relatively solid state and wherein, after stretching in the second direction, said converting step comprises heating said coated polymeric sheet to a temperature and for a period of time sufficient to completely cure said filler material into said solid state.
Claim 24
Dependent Claim
65 words
A method as defined in claim 21 wherein said liquid filler material is a precursor of a polyurethane and wherein said converting step comprises heating said coated polymeric sheet, after stretching in the second direction, to a temperature of from about 35° C. to about 150° C. for at least about 20 seconds so as to cause complete conversion of said precursor into said polyurethane.
Claim 25
Dependent Claim
37 words
A method as defined in claim 22 wherein said converting step comprises heating said coated polymeric sheet to a temperature of from about 95° C. to about 125° C. for about 40 seconds to about 5 minutes.
Claim 26
Dependent Claim
18 words
A method as defined in claim 21 wherein said heating also serves to heat set said polymeric sheet.
Claim 27
Dependent Claim
31 words
A method as defined in claim 1 wherein after the converting step said polymeric sheet has a moisture vapor transmission rate of at least about 1000 g/m 2 per 24 hours.
Claim 28
Dependent Claim
27 words
A method as defined in claim 1 wherein after said converting step said polymeric sheet has a thickness of from about 7 micrometers to about 125 micrometers.
Claim 29
Dependent Claim
23 words
A method as defined in claim 1 further comprising the step of laminating a fabric to said polymeric sheet after said converting step.
Claim 30
Independent Claim
317 words
A method of preparing a breathable, waterproof material, the method comprising the steps of: preparing a sheet of polymeric material, said preparing step comprising: melt blending to form a solution comprising a crystallizable thermoplastic polymer and a compound with which said thermoplastic polymer is miscible and in which said thermoplastic polymer will dissolve at the melting temperature of said thermoplastic polymer but which will phase separate on cooling to a temperature at or below the crystallization temperature of said thermoplastic polymer; forming a sheet from the melt blended solution; and cooling said sheet to a temperature at which said thermoplastic polymer crystallizes to cause phase separation to occur between said compound and said polymer, thereby providing said sheet with an aggregate of a first phase comprising particles of crystallized thermoplastic polymer in a second phase comprising said compound with adjacent thermoplastic polymer particles being distinct but having a plurality of zones of continuity; stretching said polymeric sheet from about 100% to about 400% in the lengthwise direction so as to render said sheet more microporous; coating said polymeric sheet, after said polymeric sheet has been stretched in the lengthwise direction, with a liquid filler material which can be cured to form a solid hydrophilic material which is water vapor permeable and liquid water impermeable, said liquid filler material being capable of substantially filling the micropores of said polymeric sheet; stretching said coated polymeric sheet, after said coating step, from about 100% to about 400% in the transverse direction so as to render said polymeric sheet more microporous, said stretching of said polymeric sheet in the transverse direction serving to significantly enhance infiltration of said liquid filler material into the micropores of said polymeric sheet; and converting said liquid filler material into said solid hydrophilic material by heating said infiltrated polymeric sheet to a temperature and for a period of time sufficient to completely cure said filler material.
Claim 31
Independent Claim
317 words
A method of preparing a breathable, waterproof material, the method comprising the steps of: preparing a sheet of polymeric material, said preparing step comprising: melt blending to form a solution comprising a crystallizable thermoplastic polymer and a compound with which said thermoplastic polymer is miscible and in which said thermoplastic polymer will dissolve at the melting temperature of said thermoplastic polymer but which will phase separate on cooling to a temperature at or below the crystallization temperature of said thermoplastic polymer; forming a sheet from the melt blended solution; and cooling said sheet to a temperature at which said thermoplastic polymer crystallizes to cause phase separation to occur between said compound and said polymer, thereby providing said sheet with an aggregate of a first phase comprising particles of crystallized thermoplastic polymer in a second phase comprising said compound with adjacent thermoplastic polymer particles being distinct but having a plurality of zones of continuity; stretching said polymeric sheet from about 100% to about 400% in the lengthwise direction so as to render said sheet more microporous; coating said polymeric sheet, after said polymeric sheet has been stretched in the lengthwise direction, with a liquid filler material which can be cured to form a solid hydrophilic material which is water vapor permeable and liquid water impermeable, said liquid filler material being capable of substantially filling the micropores of said polymeric sheet; stretching said coated polymeric sheet, after said coating step, from about 100% to about 400% in the transverse direction so as to render said polymeric sheet more microporous, said stretching of said polymeric sheet in the transverse direction serving to significantly enhance infiltration of said liquid filler material into the micropores of said polymeric sheet; and converting said liquid filler material into said solid hydrophilic material by heating said infiltrated polymeric sheet to a temperature and for a period of time sufficient to completely cure said filler material.
Claim 32
Dependent Claim
23 words
A method as defined in claim 28 wherein said polymeric sheet is stretched from about 200% to about 300% in the lengthwise direction.
Claim 33
Dependent Claim
29 words
A method as defined in claim 28 wherein said polymeric sheet has a thickness of from about 30 micrometers to about 75 micrometers after stretching in the lengthwise direction.
Claim 34
Dependent Claim
24 words
A method as defined in claim 28 wherein said liquid filler material has a viscosity of from about 10 centipoise to about 100 centipoise.
Claim 35
Dependent Claim
35 words
A method as defined in claim 28 wherein the weight of said liquid filler material applied during said coating step represents from about 100% to about 500% of the weight of the uncoated polymeric sheet.
Claim 36
Dependent Claim
44 words
A method as defined in claim 28 wherein during stretching in the transverse direction said coated polymeric sheet is heated to a temperature of from about 55° C. to about 80° C. for a period of from about 20 seconds to about 40 seconds.
Claim 37
Dependent Claim
24 words
A method as defined in claim 28 wherein said coated polymeric sheet is stretched from about 150% to about 300% in the transverse direction.
Claim 38
Dependent Claim
27 words
A method as defined in claim 28 wherein after said converting step said polymeric sheet has a thickness of from about 7 micrometers to about 50 micrometers.
Claim 39
Dependent Claim
159 words
A method as defined in claim 28 wherein: said polymeric sheet is stretched from about 200% to about 300% in the lengthwise direction; said polymeric sheet has a thickness of from about 33 micrometers to about 51 micrometers after stretching in the lengthwise direction; said liquid filler material has a viscosity of from about 20 centipoise to about 60 centipoise; the weight of said liquid filler material applied during said coating step represents from about 300% to about 400% of the weight of the uncoated polymeric sheet; during stretching in the transverse direction said coated polymeric sheet is heated to a temperature of from about 60° C. to about 77° C. for a period of from about 20 seconds to about 40 seconds; said coated polymeric sheet is stretched from about 200% to about 300% in the transverse direction; and after said converting step said polymeric sheet has a thickness of from about 7 micrometers to about 25 micrometers.
Claim 40
Dependent Claim
35 words
A method as defined in claim 2 wherein the weight of said liquid filler material applied during said coating step represents from about 100% to about 500% of the weight of the uncoated polymeric sheet.
Claim 41
Dependent Claim
35 words
A method as defined in claim 2 wherein the weight of said liquid filler material applied during said coating step represents from about 300% to about 400% of the weight of the uncoated polymeric sheet.
Claim 42
Dependent Claim
23 words
A method as defined in claim 2 wherein said polymeric sheet is stretched from about 100% to about 400% in the first direction.
Claim 43
Dependent Claim
23 words
A method as defined in claim 2 wherein said polymeric sheet is stretched from about 200% to about 300% in the first direction.
Claim 44
Dependent Claim
23 words
A method as defined in claim 2 wherein said polymeric sheet is stretched from about 100% to about 400% in the second direction.
Claim 45
Dependent Claim
23 words
A method as defined in claim 2 wherein said polymeric sheet is stretched from about 150% to about 300% in the second direction.
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| 3.5 Years (Year 4) | 1992-05-22 | 1992-11-21 | 1993-05-23 | $2000.00 | Window Closed / Lapsed |
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