US4245073A
Expired / Lapsed
US
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Process for the polymerization of vinyl chloride in aqueous suspension
Assignee: Solvay SA
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Filing: 1976-05-03
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Granted: 1981-01-13
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Expires: 1996-05-03
Abstract
Abstract Process for the polymerization of vinyl chloride in aqueous suspension in the presence of dialkyl peroxydicarbonates in which the polymer is treated with a monobasic hydroxide at the end of polymerization and before the unreacted vinyl chloride is removed. The alkaline treatment is advantageously applied to polymers that are subsequently subjected to steam stripping. The treatment improves the initial heat stability of vinyl chloride polymers.
Inventors
- 👤 Stephane Noel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:44
CPC Classifications
C; C08; C08F; C08F6/00; C08F6/001; C08F6/003
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
66 words
In a process for the polymerisation of vinyl chloride in which vinyl chloride is polymerised in aqueous suspension in the presence of a dialkyl peroxydicarbonate and in which the polymer is treated with a hydroxide, the improvement consisting essentially in treating the polymer in the aqueous suspension with a monobasic hydroxide when the desired conversion has been achieved and before the unreacted vinyl chloride is removed.
Claim 2
Dependent Claim
66 words
In a process for the polymerisation of vinyl chloride in which vinyl chloride is polymerised in aqueous suspension in the presence of a dialkyl peroxydicarbonate and in which the polymer is treated with a hydroxide, the improvement consisting essentially in treating the polymer in the aqueous suspension with a monobasic hydroxide when the desired conversion has been achieved and before the unreacted vinyl chloride is removed.
Claim 3
Dependent Claim
25 words
Process as in claim 1, wherein the amount of monobasic hydroxide used is such that the pH of the aqueous suspension is at least 7.
Claim 4
Dependent Claim
25 words
Process as in claim 1, wherein the amount of monobasic hydroxide used is such that the pH of the aqueous suspension does not exceed 12.
Claim 5
Dependent Claim
26 words
Process as in claim 1, wherein the amount of monobasic hydroxide used is such that the pH of the aqueous suspension is between 9 and 10.5.
Claim 6
Dependent Claim
18 words
Process as in claim 1, wherein the monobasic hydroxide is selected from ammonium, lithium, potassium and sodium hydroxides.
Claim 7
Dependent Claim
12 words
Process as in claim 5, wherein the monobasic hydroxide is ammonium hydroxide.
Claim 8
Dependent Claim
18 words
Process as in claim 1, wherein the monobasic hydroxide is used in the form of an aqueous solution.
Claim 9
Dependent Claim
26 words
Process as in claim 1, wherein the aqueous suspension that is treated still contains at least 10 g of vinyl chloride per 1 kg of polymer.
Claim 10
Dependent Claim
21 words
Process as in claim 1, wherein the aqueous suspension is treated with the monobasic hydroxide for between 5 and 120 minutes.
Claim 11
Dependent Claim
14 words
Process as in claim 1, wherein an antioxidant is incorporated in the aqueous suspension.
Claim 12
Dependent Claim
23 words
Process as in claim 10, wherein the antioxidant is incorporated at the end of polymerisation and before the unconverted vinyl chloride is removed.
Claim 13
Dependent Claim
21 words
Process as in claim 10, wherein the incorporation of the antioxidant precedes the treatment of the polymer with a monobasic hydroxide.
Claim 14
Dependent Claim
12 words
Process as in claim 10, wherein the antioxidant is a phenolic compound.
Claim 15
Dependent Claim
22 words
Process as in claim 1, wherein the aqueous suspension treated with the monobasic hydroxide is subjected to stripping with an inert fluid.
Claim 16
Dependent Claim
11 words
Process as in claim 14, wherein the inert fluid is steam.
Claim 17
Dependent Claim
17 words
Process as in claim 14, wherein the treated aqueous suspension is degassed before being subjected to stripping.
Claim 18
Dependent Claim
49 words
Process as in claim 14, wherein the treated aqueous suspension is heated to a temperature at least equal to the glass transition temperature of the polymer and is maintained at a temperature at least equal to the glass transition temperature of the polymer during stripping with an inert fluid.
Claim 19
Dependent Claim
48 words
Process as in claim 1, wherein the polymer is treated with ammonium hydroxide in an amount which is such that the pH of the suspension is between 9 and 10.5 while the aqueous suspension still contains at least 25 g of vinyl chloride per 1 kg of polymer.
Claim 20
Dependent Claim
36 words
Process as in claim 1, wherein the aqueous suspension is an aqueous suspension of a vinyl chloride polymer polymerised in the presence of a dialkyl peroxydicarbonate whose alkyl chains contain from 1 to 9 carbon atoms.
Claim 21
Dependent Claim
16 words
Process as in claim 19, wherein the alkyl chains contain from 1 to 4 carbon atoms.
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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) | 1984-01-13 | 1984-07-14 | 1985-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-13 | 1988-07-14 | 1989-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-13 | 1992-07-14 | 1993-01-13 | $7700.00 | Window Closed / Lapsed |