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US3943045A
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Irradiation of hydrophilic and hydrophobic monomers to produce hydrophilic copolymers
Assignee: Special Polymers Ltd
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Filing: 1973-03-12
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Granted: 1976-03-09
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Expires: 1993-03-12
Abstract
Abstract A hydrophilic polymer or copolymer is produced in an environment free from a chemical initiator and preferably by irradiation of the starting materials, particularly by gamma rays. The product polymer or copolymer is thus free from the residua of chemical initiators and the method permits the production of polymers and copolymers which are particularly suitable for use in contact with living tissue, for example as contact lenses, prosthetic devices, surgical implants, protective corneal fittings and protective membranes or bandages.
Inventors
- 👤 Philip William Cordrey
- 👤 John David Frankland
- 👤 Donald James Highgate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:15
CPC Classifications
G; G02; G02B; G02B1/00; G02B1/04; G02B1/041; G02B1/043; B; B29; B29D; B29D11/00; B29D11/00009; C; C08; C08F; C08F2/00; C08F2/46; C08F291/00; C08F291/18
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
142 words
A method for the production of a hydrophilic copolymer, which comprises subjecting to copolymerization an initial mixture of (a) hydrophilic monomer selected from the group consisting of methacrylic acid, acrylic acid, N-vinyl pyrrolidones, vinyl pyridines, hydroxy alkyl methacrylates and mixtures thereof, and (b) hydrophobic monomer selected from the group consisting of alkyl acrylates, alkyl methacrylates, styrene and diethyleneglycol bis(allyl carbonate) and, as the only monomers in the polymerization system, said monomers being mixed in a molar ratio of a/b in the range of 10/1 to 1/2, in an environment free of chemical polymerization initiator and any residue thereof, by subjecting the initial mixture to electromagnetic radiation in the ultraviolet-gamma ray range using a radiation dosage of from 2 to 5 megarads administered over a time period of from one to 48 hours, to give a degree of polymerization of at least 95%.
Claim 2
Independent Claim
142 words
A method for the production of a hydrophilic copolymer, which comprises subjecting to copolymerization an initial mixture of (a) hydrophilic monomer selected from the group consisting of methacrylic acid, acrylic acid, N-vinyl pyrrolidones, vinyl pyridines, hydroxy alkyl methacrylates and mixtures thereof, and (b) hydrophobic monomer selected from the group consisting of alkyl acrylates, alkyl methacrylates, styrene and diethyleneglycol bis(allyl carbonate) and, as the only monomers in the polymerization system, said monomers being mixed in a molar ratio of a/b in the range of 10/1 to 1/2, in an environment free of chemical polymerization initiator and any residue thereof, by subjecting the initial mixture to electromagnetic radiation in the ultraviolet-gamma ray range using a radiation dosage of from 2 to 5 megarads administered over a time period of from one to 48 hours, to give a degree of polymerization of at least 95%.
Claim 3
Dependent Claim
21 words
A method according to claim 1, in which the radiation has a quantum energy in the range 60 - 100 MeV.
Claim 4
Dependent Claim
13 words
A method according to claim 1, in which the radiation is gamma rays.
Claim 5
Dependent Claim
14 words
A method according to claim 3, in which the radiation source is cobalt 60.
Claim 6
Dependent Claim
14 words
A method according to claim 4, in which said dosage is substantially 2.5 Megarads.
Claim 7
Dependent Claim
24 words
A method according to claim 3, in which the hydrophobic monomer is a member of the group consisting of methyl acrylate and methyl methacrylate.
Claim 8
Dependent Claim
22 words
A method according to claim 3, in which said hydrophilic monomer is a member of the group consisting of N-vinyl-pyrrolidones and vinylpyridines.
Claim 9
Dependent Claim
22 words
A method according to claim 3, in which said hydrophilic monomer is a member of the group consisting of N-vinyl-2-pyrrolidone and 4-vinylpyridine.
Claim 10
Dependent Claim
20 words
A method according to claim 3, in which said molar ratio is from 5 : 1 to 2 : 1.
Claim 11
Dependent Claim
25 words
A method according to claim 3, in which the polymerisation is carried out in the presence of a minor proportion of a selective cross-linking agent.
Claim 12
Dependent Claim
26 words
A method according to claim 10, in which the cross-linking agent is a member of the group consisting of allyl methacrylate, divinylbenzene and ethylene glycol dimethacrylate.
Claim 13
Dependent Claim
20 words
A method according to Claim 3, in which said initial mixture consists essentially of N-vinyl-2-pyrrolidone, methyl methacrylate and allyl methacrylate.
Claim 14
Dependent Claim
16 words
A method according to Claim 3, in which said hydrophilic monomer consists of a hydroxyalkyl methacrylate.
Claim 15
Dependent Claim
22 words
A method according to Claim 3, in which said hydrophilic monomer consists of N-vinyl-2-pyrrolidone and said hydrophobic monomer consists of methyl methacrylate.
Claim 16
Dependent Claim
15 words
A method according to claim 3, carried out in vacuo or in an inert atmosphere.
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) | 1979-03-09 | 1979-09-08 | 1980-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-09 | 1983-09-08 | 1984-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-09 | 1987-09-08 | 1988-03-09 | $7700.00 | Window Closed / Lapsed |