US4192842A
Expired / Lapsed
US
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Method for casting ultrathin methylpentene polymer membranes
Assignee: General Electric Co
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Filing: 1978-10-10
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Granted: 1980-03-11
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Expires: 1998-10-10
Abstract
Abstract An improved method is described for solvent casting ultrathin non-porous methylpentene polymer films. The casting solution comprises methylpentene polymer or a mixture thereof with organopolysiloxane-polycarbonate copolymer dissolved in a solvent system and is characterized by being able to spontaneously spread over the surface of the liquid casting substrate. In a preferred embodiment, large-area films less than 200 Angstroms in thickness may be repeatedly formed. The solidified films remain relatively free of tensile stress during formation. The casting solution is deposited in a narrow, longitudinally-extending defined region at the surface of the casting substrate. The surface area and perimeter of the defined region are enlarged over the surface of the casting substrate in a manner whereby the casting solution is moved relative to the casting substrate and, after desolvation, the polymer film formed remains stationary relative to the casting substrate and relatively free of tensile stress. The films are useful as semipermeable membranes for selectively removing oxygen gas from mixtures thereof with nitrogen gas.
Inventors
- 👤 Shiro G. Kimura
- 👤 Raymond G. Lavigne
- 👤 Warella R. Browall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:59
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/26; B01D53/00; B01D53/22; B01D53/228; B01D69/00; B01D69/12; B01D69/122; B29; B29D; B29D7/00; B29D7/01
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
101 words
A process of casting a thin solid film of a methylpentene polymeric composition which comprises: (a) depositing onto the surface of a liquid casting substrate a quantity of a casting solution comprising a solvent system and dissolved therein a methylpentene polymer and from zero to about 100 parts by weight of an organopolysiloxane-polycarbonate copolymer per 100 parts by weight of said methylpentene polymer, said casting solution being able to spontaneously spread over said substrate, and (b) allowing the deposited solution to both spontaneously spread over said substrate and desolvate to effect formation of a thin solid film comprising methylpentene polymeric composition.
Claim 2
Dependent Claim
101 words
A process of casting a thin solid film of a methylpentene polymeric composition which comprises: (a) depositing onto the surface of a liquid casting substrate a quantity of a casting solution comprising a solvent system and dissolved therein a methylpentene polymer and from zero to about 100 parts by weight of an organopolysiloxane-polycarbonate copolymer per 100 parts by weight of said methylpentene polymer, said casting solution being able to spontaneously spread over said substrate, and (b) allowing the deposited solution to both spontaneously spread over said substrate and desolvate to effect formation of a thin solid film comprising methylpentene polymeric composition.
Claim 3
Dependent Claim
26 words
The process of claim 1 wherein the solvent system is present in an amount of from about 93 to about 99% by weight of said solution.
Claim 4
Dependent Claim
14 words
The process of claim 1 wherein the liquid of said casting substrate is water.
Claim 5
Dependent Claim
17 words
The process of claim 1 wherein the organopolysiloxane-polycarbonate copolymer comprises dimethylsiloxane and bisphenol-A carbonate polymerized monomer units.
Claim 6
Dependent Claim
31 words
The process of claim 1 wherein the copolymer is present in an amount of from about 1 to about 25 parts by weight per 100 parts by weight of methylpentene polymer.
Claim 7
Dependent Claim
22 words
The process of claim 1 wherein the methylpentene polymer is a 4-methylpentene-1 homopolymer having a weight average molecular weight of about 140,000.
Claim 8
Dependent Claim
232 words
In the process of forming a thin solid polymer film wherein a quantity of casting solution comprising film-forming polymer dissolved in a solvent system is deposited in a narrow, longitudinally-extending defined region on the surface of a liquid casting substrate bounded by barriers, said casting solution being able to spontaneously spread over said substrate, separation of said barriers is effectuated so that both the surface area and perimeter of said defined region are enlarged over the surface of said substrate in a direction transverse to the longitudinal direction of the original defined region to permit controlled spontaneous spreading and desolvation of the deposited solution to form a thin desolvated, solid polymer film covering an area much larger than the area of said originally defined region, the rate of said barrier separation relative to the volatility of said solvent system during effectuation of separation is such that: (a) casting solution alone moves relative to said substrate and (b) the solid polymer film being formed remains stationary relative to said substrate, and at least a portion of the solid film is removed from the surface of said substrate, said film portion being relatively free of applied tensile stress during the formation thereof, the improvement comprising the dissolved polymer comprises a methylpentene polymer and from 0 to about 100 parts by weight per 100 parts by weight of said methylpentene polymer of an organopolysiloxane-polycarbonate copolymer.
Claim 9
Dependent Claim
232 words
In the process of forming a thin solid polymer film wherein a quantity of casting solution comprising film-forming polymer dissolved in a solvent system is deposited in a narrow, longitudinally-extending defined region on the surface of a liquid casting substrate bounded by barriers, said casting solution being able to spontaneously spread over said substrate, separation of said barriers is effectuated so that both the surface area and perimeter of said defined region are enlarged over the surface of said substrate in a direction transverse to the longitudinal direction of the original defined region to permit controlled spontaneous spreading and desolvation of the deposited solution to form a thin desolvated, solid polymer film covering an area much larger than the area of said originally defined region, the rate of said barrier separation relative to the volatility of said solvent system during effectuation of separation is such that: (a) casting solution alone moves relative to said substrate and (b) the solid polymer film being formed remains stationary relative to said substrate, and at least a portion of the solid film is removed from the surface of said substrate, said film portion being relatively free of applied tensile stress during the formation thereof, the improvement comprising the dissolved polymer comprises a methylpentene polymer and from 0 to about 100 parts by weight per 100 parts by weight of said methylpentene polymer of an organopolysiloxane-polycarbonate copolymer.
Claim 10
Dependent Claim
26 words
The improvement of claim 7 wherein the solvent system is present in an amount of from about 93 to about 99% be weight of said solution.
Claim 11
Dependent Claim
14 words
The improvement of claim 7 where the liquid of said casting substrate is water.
Claim 12
Dependent Claim
17 words
The improvement of claim 7 wherein the organopolysiloxane-polycarbonate copolymer comprises dimethylsiloxane and bisphenol-A carbonate polymerized monomer units.
Claim 13
Dependent Claim
31 words
The improvement of claim 7 wherein the copolymer is present in an amount of from about 1 to about 25 parts by weight per 100 parts by weight of methylpentene polymer.
Claim 14
Dependent Claim
22 words
The improvement of claim 7 wherein the methylpentene polymer is a 4-methylpentene-1 homopolymer having a weight average molecular weight of about 140,000.
Claim 15
Dependent Claim
91 words
The improvement of claim 7 wherein said casting solution is deposited at a solution temperature of slightly more than T 1 to about T 2 where T 1 is no less than the lowest temperature at which substantially all the polymer present in said solvent system is soluble therein, T 2 is the lesser of (a) about 90° C. and (b) the temperature at which the vapor pressure of said solution is equal to the pressure at the surface of said substrate, and T 1 is less than T 2 .
Claim 16
Dependent Claim
19 words
The improvement of claim 13 wherein said casting substrate is at a temperature of less than T 1 .
Claim 17
Dependent Claim
79 words
The improvement of claim 13 wherein the solvent system comprises a solvent selected from the group consisting of trichloroethylene, tetrachloroethylene, 1,2,3-trichloropropane, chloroform, methylene chloride, and mixtures thereof, T 1 is at least 50° C., said casting substrate is at a temperature of from about 20° C. to about 60° C., the liquid of said casting substrate is water, and the solvent system is present in an amount of from about 93 to about 99% by weight of said solution.
Claim 18
Dependent Claim
91 words
The process of claim 1 wherein said casting solution is deposited at a solution temperature of slightly more than T 1 to about T 2 where T 1 is no less than the lowest temperature at which substantially all the polymer present in said solvent system is soluble therein, T 2 is the lesser of (a) about 90° C. and (b) the temperature at which the vapor pressure of said solution is equal to the pressure at the surface of said substrate, and T 1 is less than T 2 .
Claim 19
Dependent Claim
19 words
The process of claim 16 wherein said casting substrate is at a temperature of less than T 1 .
Claim 20
Dependent Claim
14 words
The improvement of claim 7 wherein each of said barriers has a hydrophobic coating.
Claim 21
Dependent Claim
30 words
The improvement of claim 7, wherein said copolymer is present in an amount of up to about 100 parts by weight per 100 parts by weight of said methylpentene polymer.
Claim 22
Dependent Claim
30 words
The process of claim 1, wherein said copolymer is present in an amount of up to about 100 parts by weight per 100 parts by weight of said methylpentene polymer.
Claim 23
Dependent Claim
79 words
The process of claim 16 wherein the solvent system comprises a solvent selected from the group consisting of trichloroethylene, tetrachloroethylene, 1,2,3-trichloropropane, chloroform, methylene chloride, and mixtures thereof, T 1 is at least 50° C., said casting substrate is at a temperature of from about 20° C. to about 60° C., the liquid of said casting substrate is water, and the solvent system is present in an amount of from about 93 to about 99% by weight of said solution.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-03-11 | 1983-09-10 | 1984-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-11 | 1987-09-10 | 1988-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-11 | 1991-09-10 | 1992-03-11 | $7700.00 | Window Closed / Lapsed |