US5185385A
Expired / Lapsed
US
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Polymerization process
Assignee: Huntsman Corp
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Filing: 1991-04-15
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Granted: 1993-02-09
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Expires: 2011-04-15
Abstract
Abstract Vinyl monomers are polymerized in high yield to water-soluble polymers or copolymers by free radical polymerization of an aqueous reaction mixture containing the vinyl monomer(s), an UV-activated photoinitiator and a heat-activated chemical initiator. The polymerization is initially carried out by exposing the monomer mixture to UV radiation to activate the photoinitiator and then is carried out under the influence of free radicals produced by the chemical initiator.
Inventors
- 👤 Ratana Kanluen
- 👤 Brigitte H. Licht
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:41
CPC Classifications
C; C08; C08F; C08F2/00; C08F2/46; C08F2/48
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
190 words
A method of polymerizing at least one vinyl monomer to a particulate, water-soluble, substantially linear polymer or copolymer, which comprises: forming an aqueous monomer solution mixture having a pH of about 3 to about 7 comprising at least one vinyl monomer polymerizable to said water soluble polymer or copolymer, an ultraviolet-decomposable free radical initiator capable of producing free radicals upon exposure to ultraviolet radiation, and a chemical free radical initiator capable of producing free radicals upon heating above a predetermined temperature, initiating polymerization of said at least one monomer by irradiating said monomer mixture with long wavelength ultraviolet radiation in the wavelength from about 300 to about 400 nm, permitting said polymerization to be effected while said monomer mixture increases in temperature to said predetermined temperature, so as to activate said chemical initiator, discontinuing said irradiation and permitting said polymerization of said at least one monomer to be effected above said predetermined temperature until complete while maintaining the maximum temperature of said monomer mixture in the range of about 60° C. to about 90° C. to obtain the polymer in a yield exceeding 99%, and particulating the polymer so produced.
Claim 2
Independent Claim
190 words
A method of polymerizing at least one vinyl monomer to a particulate, water-soluble, substantially linear polymer or copolymer, which comprises: forming an aqueous monomer solution mixture having a pH of about 3 to about 7 comprising at least one vinyl monomer polymerizable to said water soluble polymer or copolymer, an ultraviolet-decomposable free radical initiator capable of producing free radicals upon exposure to ultraviolet radiation, and a chemical free radical initiator capable of producing free radicals upon heating above a predetermined temperature, initiating polymerization of said at least one monomer by irradiating said monomer mixture with long wavelength ultraviolet radiation in the wavelength from about 300 to about 400 nm, permitting said polymerization to be effected while said monomer mixture increases in temperature to said predetermined temperature, so as to activate said chemical initiator, discontinuing said irradiation and permitting said polymerization of said at least one monomer to be effected above said predetermined temperature until complete while maintaining the maximum temperature of said monomer mixture in the range of about 60° C. to about 90° C. to obtain the polymer in a yield exceeding 99%, and particulating the polymer so produced.
Claim 3
Dependent Claim
69 words
The method of claim 1 wherein said vinyl, monomer has the formula: ##STR3## wherein: R represents hydrogen, a methyl group or an ethyl group; and Y represents ##STR4## or its alkali metal salts in which R 1 , R 2 and R 3 individually represent alkali groups containing from 1 to 4 carbon atoms, M⊕ represents NH 4 ⊖ or an alkali metal cation, and X⊖ represents an anion.
Claim 4
Dependent Claim
29 words
The method of claim 2 wherein said ultraviolet radiation is applied to said monomer mixture at an applied radiation intensity of about 1000 to about 4000 microwatts/cm 2 .
Claim 5
Dependent Claim
26 words
The method of claim 3 wherein said photoinitiator is used in an amount of about 40 to about 200 ppm, based on the weight of monomer.
Claim 6
Dependent Claim
23 words
The method of claim 4 wherein said predetermined temperature of dissociation of said chemical initiator is about 35° C. to about 70° C.
Claim 7
Dependent Claim
27 words
The method of claim 5 wherein said chemical initiator is used in an amount of about 50 to about 400 ppm, based on the weight of monomer.
Claim 8
Dependent Claim
17 words
The method of claim 6 wherein said monomer mixture also contains at least one chain transfer agent.
Claim 9
Dependent Claim
26 words
The method of claim 7 wherein said chain transfer agent is present in an amount up to about 25,000 ppm, based on the weight of monomer.
Claim 10
Dependent Claim
25 words
The method of claim 8 wherein said monomer(s) is present in the monomer mixture in a concentration of about 30 to about 7 wt. %.
Claim 11
Dependent Claim
31 words
The method of claim 9 wherein said polymerization process is effected in a batch operation using a monomer mixture having a depth of from a few millimeters to about 10 cms.
Claim 12
Dependent Claim
63 words
The method of claim 9 wherein said polymerization is effected in a continuous operation in which successive batches of monomer mixture contained in shallow trays to a depth of from a few millimeters to about 10 cms are exposed to ultraviolet radiation until said predetermined temperature is reached and the tray is removed from said exposure to be replaced by the next tray.
Claim 13
Dependent Claim
25 words
The method of claim 1 effected to produce a vinyl polymer or copolymer of molecular weight in the range of about 50,000 to about 15,000,000.
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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) | 1996-02-09 | 1996-08-10 | 1997-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-02-09 | 2000-08-10 | 2001-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-02-09 | 2004-08-10 | 2005-02-09 | $7700.00 | Window Closed / Lapsed |