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US4404073A
Expired / Lapsed
US
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Photopolymerization of olefinically unsaturated monomers utilizing benzil dimethylacetal
Assignee: Rhone Poulenc Industries SA
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Filing: 1981-09-03
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Granted: 1983-09-13
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Expires: 2001-09-03
Abstract
Abstract High molecular weight water-soluble polymers essentially devoid of residual monomer content and well adapted for use as flocculating agents, are prepared by photopolymerizing a thin layer of a deoxygenated aqueous solution of an olefinically unsaturated monomer continuously deposited upon a travelling support substrate, said aqueous solution containing a photopolymerization photoinitiator and said photoinitiator comprising benzil dimethylacetal.
Inventors
- 👤 Alain Bartissol
- 👤 Jean Boutin
- 👤 Francois Wachowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:35
CPC Classifications
C; C08; C08F; C08F2/00; C08F2/46; C08F2/48
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
75 words
A process for the preparation of a high molecular weight water-soluble polymer essentially devoid of residual monomer content and having an increased rate of dissolution, comprising photopolymerizing a thin layer of a deoxygenated aqueous solution of an olefinically unsaturated monomer continuously deposited upon a travelling support substrate, said aqueous solution containing a photopolymerization photoinitiator and said photoinitiator comprising benzil dimethylacetal at from 0.001% to 0.5% by weight based upon the weight of the monomer photopolymerized.
Claim 2
Dependent Claim
75 words
A process for the preparation of a high molecular weight water-soluble polymer essentially devoid of residual monomer content and having an increased rate of dissolution, comprising photopolymerizing a thin layer of a deoxygenated aqueous solution of an olefinically unsaturated monomer continuously deposited upon a travelling support substrate, said aqueous solution containing a photopolymerization photoinitiator and said photoinitiator comprising benzil dimethylacetal at from 0.001% to 0.5% by weight based upon the weight of the monomer photopolymerized.
Claim 3
Dependent Claim
24 words
The process as defined by claim 1, said photopolymerization being effected via irradiation with radiation having a wavelength ranging from 150 to 500 nm.
Claim 4
Dependent Claim
18 words
The process as defined by claim 2, said radiation having a wavelength ranging from 300 to 450 nm.
Claim 5
Dependent Claim
19 words
The process as defined by claim 1, said amount of benzil dimethylacetal ranging from 0.003% to 0.3% by weight.
Claim 6
Dependent Claim
69 words
The process as defined by claim 1, wherein the aqueous monomer solution contains less than 1 mg of oxygen per liter of solution and is exposed, for 5 to 20 minutes, in a moist atmosphere having an oxygen content of less than 5% by volume, to radiation having wavelengths ranging from 300 and 450 nm, having an active radiation intensity, applied increasingly, of 20 to 2,000 watts/m 2 .
Claim 7
Dependent Claim
48 words
The process as defined by claims 1 or 5, wherein the monomer is selected from the group comprising acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, methallylsulfonic acid, vinylbenzenesulfonic acid, the salts and esters of such acids, N-vinyl-pyrrolidone, 2-methyl-5-vinyl-pyridine, optionally quaternized aminoalkyl acrylates and methacrylates, and admixtures thereof.
Claim 8
Dependent Claim
59 words
The process as defined by claim 6, wherein the thin layer of aqueous monomer solution has a thickness ranging from 2 to 20 mm, the travelling support is externally cooled and the pH is either maintained from 8 to 14 in order to obtain non-ionic or anionic polymers, or from 2 to 8 in order to obtain cationic polymers.
Claim 9
Dependent Claim
43 words
The process as defined by claim 6, wherein the aqueous solution subjected to photopolymerization contains a photopolymerization adjuvant selected from the group comprising gluconic acid and its sodium, potassium and ammonium salts, saccharic acid and its sodium and potassium salts, and adipic acid.
Claim 10
Dependent Claim
78 words
The process as defined by claim 6, wherein at least one of the two face surfaces of the rubbery layer obtained after irradiation is coated with at least one alkali metal sulfite and/or at least one alkali metal metabisulfite, the amount of alkali metal sulfite and/or metabisulfite ranging from 0.1% to about 3% by weight relative to the weight of the rubbery layer, and said rubbery layer is thence chopped into flakes which are then dried and ground.
Claim 11
Dependent Claim
47 words
The process as defined by claim 9, wherein the aqueous solution of acrylic monomer has a pH less than or equal to 12, and at least one carbonate selected from the group comprising the alkali metal carbonates is coated simultaneously with the alkali metal sulfite and/or metabisulfite.
Claim 12
Dependent Claim
13 words
The process as defined by claim 10, wherein the carbonate is ammonium carbonate.
Claim 13
Dependent Claim
19 words
The process as defined by claim 7, said thin layer having a thickness ranging from 3 to 8 mm.
Claim 14
Dependent Claim
23 words
The process as defined by claim 9, the amount of alkali metal sulfite and/or bisulfite ranging from 0.3% to about 2% by weight.
Claim 15
Dependent Claim
10 words
The product of the process as defined by claim 1.
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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) | 1986-09-12 | 1987-03-14 | 1987-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-12 | 1991-03-14 | 1991-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-12 | 1995-03-14 | 1995-09-13 | $7700.00 | Window Closed / Lapsed |