US3955014A
Expired / Lapsed
US
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Method of making alkali battery separators
Assignee: Zlehit Pri Ban
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Filing: 1974-05-31
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Granted: 1976-05-04
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Expires: 1994-05-31
Abstract
Abstract A method of obtaining alkaline battery separators. Such method comprises ultraviolet irradiation in the presence of a sensitizer and oxygen contained in the air of low density polyethylene film at ambient temperature and normal pressure to effect cross-linking and subsequently graft polymerizing an ethylenically unsaturated carboxylic acid monomer into the irradiated film under the action of heat and compression of the film.
Inventors
- 👤 Rafail Velislavov Mostev
- 👤 Hrisanta Nicolaeva Budevska
- 👤 Latinca Tantilova Ivanova
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:34
CPC Classifications
H; H01; H01M; H01M50/00; H01M50/40; H01M50/409; H01M50/411; H01M50/414; H01M50/417; H01M50/489; H01M2300/00; H01M2300/0002; H01M2300/0014; H01M50/494; Y; Y02; Y02E; Y02E60/00; Y02E60/10
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
85 words
A method of producing alkaline battery separators comprising ultraviolet irradiating a low-density polyethylene film in the presence of a sensitizer and air at ambient temperature and normal pressure, grafting the irradiated film in the absence of any reducing agent with an ethylenically unsaturated carboxylic acid monomer at a temperature of 70°-90°C in the absence of irradiation while the film is under compression of at least 0.5 kg/cm 2 and is sandwiched with a porous web spacer, and converting the grafting film to its potassium form.
Claim 2
Independent Claim
85 words
A method of producing alkaline battery separators comprising ultraviolet irradiating a low-density polyethylene film in the presence of a sensitizer and air at ambient temperature and normal pressure, grafting the irradiated film in the absence of any reducing agent with an ethylenically unsaturated carboxylic acid monomer at a temperature of 70°-90°C in the absence of irradiation while the film is under compression of at least 0.5 kg/cm 2 and is sandwiched with a porous web spacer, and converting the grafting film to its potassium form.
Claim 3
Dependent Claim
54 words
A method according to claim 1, wherein the film is cross-linked by irradiation with an ultraviolet source radiating basically in the 250-400 nm band with an input power of 2 ± 0.5 kW per square meter of the irradiated film at a distance of 20 ± 10 cm for a period of 4-12 min.
Claim 4
Dependent Claim
18 words
A method according to claim 1, wherein the sensitizer is a 2-6% by weight benzophenone solution in toluene.
Claim 5
Dependent Claim
14 words
A method according to claim 1, wherein the polyethylene film is 20-50 microns thick.
Claim 6
Dependent Claim
43 words
A method according to claim 1, wherein the compression of the film necessary for the grafting process is created by tightly rolling up the irradiated film along with a porous web on a cylinder with a streching force of at least 1.0 kg/cm.
Claim 7
Dependent Claim
46 words
A method according to claim 1, wherein the compression necessary for the grafting process is created by subjecting a pack of irradiated polyethylene sheets in a stack with porous web spacers to a pressure of at least 0.6 ± 0.2 kg/cm 2 throughout the grafting process.
Claim 8
Dependent Claim
20 words
A method according to claim 1, wherein the film is grafted at a temperature 70°-90°C for 50 to 20 min.
Claim 9
Dependent Claim
16 words
A method according to claim 1, wherein the ethylenically unsaturated caboxylic acid is 100% methacrylic acid.
Claim 10
Dependent Claim
25 words
A method according to claim 1, wherein the film is grafted in a 50-90% by volume solution of methacrylic acid in benzene, toluene, or xylene.
Claim 11
Dependent Claim
32 words
A method according to claim 1, wherein the grafted film is converted to its potassium form by treating it in 40% by volume solution for KOH for 15 min. at 60° C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-04 | 1979-11-03 | 1980-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-04 | 1983-11-03 | 1984-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-04 | 1987-11-03 | 1988-05-04 | $7700.00 | Window Closed / Lapsed |