US3957744A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polymerization of vinyl chloride in aqueous suspension
Assignee: BASF SE
•
Filing: 1973-03-15
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Granted: 1976-05-18
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Expires: 1993-03-15
Abstract
Abstract Polymerization of vinyl chloride in aqueous suspension in the presence of free-radical initiators of short half-life at pH's below 8. The temperature of the reactor wall must not be more than 20°C above the temperature of the polymerization mixture during the heat-up phase and it must be lower than the temperature of the polymerization mixture during the subsequent polymerization phase. This procedure suppresses the formation of incrustations in the reactor.
Inventors
- 👤 Walter Deuschel
- 👤 Erich Gulbins
- 👤 Alfred Hauss
- 👤 Dietrich Lausberg
- 👤 Wilhelm Sigmund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:23
CPC Classifications
C; C08; C08F; C08F14/00; C08F14/02; C08F14/04; C08F14/06; Y; Y10; Y10S; Y10S526/00; Y10S526/91
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
163 words
A process for the polymerization of vinyl chloride or vinyl chloride and up to 30% by weight of conventional comonomers in aqueous suspension in the presence of a free-radical initiator and a water-soluble protective colloid in a stirred reactor, wherein the polymerization mixture is heated to the desired polymerization temperature in a heat-up phase which constitutes not more than one third of the time required for the full polymerization cycle, whereupon polymerization is carried out in the polymerization phase at a substantially constant temperature, which process comprises a. using at least one free-radical initiator having a half-life at 50°C of less than 10 hours, b. maintaining the polymerization mixture at a pH of less than 8 during the heat-up phase, and c. maintaining the temperature of the reactor walls above, by not more than 20°C, the temperature of the polymerization mixture during the heat-up phase and maintaining the temperature of the reactor walls below that of the polymerization mixture during the polymerization phase.
Claim 2
Dependent Claim
163 words
A process for the polymerization of vinyl chloride or vinyl chloride and up to 30% by weight of conventional comonomers in aqueous suspension in the presence of a free-radical initiator and a water-soluble protective colloid in a stirred reactor, wherein the polymerization mixture is heated to the desired polymerization temperature in a heat-up phase which constitutes not more than one third of the time required for the full polymerization cycle, whereupon polymerization is carried out in the polymerization phase at a substantially constant temperature, which process comprises a. using at least one free-radical initiator having a half-life at 50°C of less than 10 hours, b. maintaining the polymerization mixture at a pH of less than 8 during the heat-up phase, and c. maintaining the temperature of the reactor walls above, by not more than 20°C, the temperature of the polymerization mixture during the heat-up phase and maintaining the temperature of the reactor walls below that of the polymerization mixture during the polymerization phase.
Claim 3
Dependent Claim
32 words
A process as claimed in claim 1 wherein the temperature of the reactor walls are maintained above, by not more than 15°C, the temperature of the polymerization mixture during the heat-up phase.
Claim 4
Dependent Claim
18 words
A process as claimed in claim 1 wherein said pH is in the range of 3 to 7.
Claim 5
Dependent Claim
32 words
A process as claimed in claim 3 wherein the amount of free-radical initiator (a) is present in the polymerization mixture in an amount of 0.005 to 0.100% w/w, based on the monomers.
Claim 6
Dependent Claim
32 words
A process as claimed in claim 1 wherein the amount of free-radical initiator (a) is present in the polymerization mixture in an amount of 0.005 to 0.100% w/w, based on the monomers.
Claim 7
Dependent Claim
33 words
A process as claimed in claim 5 wherein said free-radical initiator (a) includes at least one member selected from the group consisting of bis-(α-ethylhexanoyl) peroxide, t-butyl perneodecanoate, diisopropyl percarbonate and acetyl cyclohexanesulfonyl peroxide.
Claim 8
Dependent Claim
31 words
A process as claimed in claim 6 wherein the free-radical initiator (a) is employed together with a more slowly decomposing initiator selected from the group consisting of lauroyl peroxide and azodiisobutyronitrile.
Claim 9
Dependent Claim
30 words
A process as claimed in claim 1 wherein the free-radical initiator (a) is employed together with a more slowly decomposing initiator selected from the group consisting of lauroyl peroxide azodiisobutyronitrile.
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) | 1979-05-18 | 1979-11-17 | 1980-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-18 | 1983-11-17 | 1984-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-18 | 1987-11-17 | 1988-05-18 | $7700.00 | Window Closed / Lapsed |