Patent US3954698A successfully refreshed from Google Patents.
US3954698A
Expired / Lapsed
US
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Polymerisation process
Assignee: European Vinyls Corp Technology AG
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Filing: 1974-12-20
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Granted: 1976-05-04
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Expires: 1994-12-20
Abstract
Abstract Vinyl halide is homopolymerized under suspension conditions with additional vinyl halide being added after the pressure drop with polymer being recovered only after the polymerisation is completed.
Inventors
- 👤 Basil John Bradley
- 👤 Peter James Craig
- 👤 Geoffrey James Gammon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:26
CPC Classifications
C; C08; C08F; C08F114/00; C08F114/02; C08F114/04; C08F114/06; Y; Y10; Y10S; Y10S526/00; Y10S526/909
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
91 words
A batch process for the homopolymerization of a vinyl halide monomer which comprises homopolymerising the monomer in aqueous suspension in the presence of a monomer soluble free radical initiator until the start of the pressure drop and thereafter adding from about 2% to not more than 50% by weight of vinyl halide based on the initial charge over not more than 15 minutes in a period in which the conversion is in the range 70% to 80% of the monomer initially added, completing the polymerisation, and only then recovering the polymer.
Claim 2
Dependent Claim
91 words
A batch process for the homopolymerization of a vinyl halide monomer which comprises homopolymerising the monomer in aqueous suspension in the presence of a monomer soluble free radical initiator until the start of the pressure drop and thereafter adding from about 2% to not more than 50% by weight of vinyl halide based on the initial charge over not more than 15 minutes in a period in which the conversion is in the range 70% to 80% of the monomer initially added, completing the polymerisation, and only then recovering the polymer.
Claim 3
Dependent Claim
18 words
A process according to claim 1 wherein the vinyl halide is added over not more than 10 minutes.
Claim 4
Dependent Claim
18 words
A process according to claim 2 wherein the vinyl halide is added over not more than 5 minutes.
Claim 5
Dependent Claim
22 words
A process according to claim 1 wherein the vinyl halide is added before the pressure has dropped by more than 30 psig.
Claim 6
Dependent Claim
27 words
A process according to claim 1 wherein the amount of vinyl halide added is from 2 to 30% by weight of the initial charge of vinyl halide.
Claim 7
Dependent Claim
22 words
A process according to claim 5 wherein the vinyl halide is added before the pressure has dropped by more than 15 psig.
Claim 8
Dependent Claim
11 words
Polyvinyl halide when made by a process according to claim 1.
References Cited (Backward Citations)
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US3324097A
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US3375238A
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US3536675A
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US3488328A
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US3661881A
Cited
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 |