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Patent US3975230A successfully refreshed from Google Patents.
US3975230A
Expired / Lapsed
US
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Steam distillation of polyvinyl chlorine slurry in presence of metal salt
Assignee: VISTA POLYMERS Inc A DE CRP AND WHOLLY-OWNED SUBSIDIARY OF VISTA CHEMICAL Co
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Filing: 1975-03-24
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Granted: 1976-08-17
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Expires: 1995-03-24
Abstract
Abstract An improvement in the process for removing vinyl chloride from a water-polyvinyl chloride slurry, which contains unreacted vinyl chloride, by steam distillation is disclosed. In many instances, steam distillation of the slurry results in an increase in the number of gels or fish eyes. The improvement comprises conducting the steam distillation in the presence of a minor, but effective, amount of an alkali metal sulfite or carbonate. The improved process results in a polyvinyl chloride having no substantial increase in, or a reduced amount of, gels or fish eyes, while still having good heat stability and porosity properties.
Inventors
- 👤 Kang Yang
- 👤 James D. Reedy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:18
CPC Classifications
B; B01; B01D; B01D3/00; B01D3/34; B01D3/38; C; C08; C08F; C08F6/00; C08F6/001; Y; Y10; Y10S; Y10S159/00; Y10S159/10
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
42 words
An improved process for removing vinyl chloride from a water-polyvinyl chloride slurry, which contains unreacted vinyl chloride, by steam distillation, wherein the improvement comprises conducting said steam distillation in the presence of an effective amount of an alkali metal sulfite or carbonate.
Claim 2
Dependent Claim
42 words
An improved process for removing vinyl chloride from a water-polyvinyl chloride slurry, which contains unreacted vinyl chloride, by steam distillation, wherein the improvement comprises conducting said steam distillation in the presence of an effective amount of an alkali metal sulfite or carbonate.
Claim 3
Dependent Claim
29 words
The process of claim 1 wherein the amount of alkali metal sulfite or carbonate is from about 0.001 to about 1% by weight based on the water-polyvinyl chloride slurry.
Claim 4
Dependent Claim
10 words
The process of claim 2 wherein sodium sulfite is used.
Claim 5
Dependent Claim
10 words
The process of claim 2 wherein sodium carbonate is used.
Claim 6
Dependent Claim
10 words
The process of claim 2 wherein potassium sulfite is used.
Claim 7
Dependent Claim
10 words
The process of claim 2 wherein potassium carbonate is used.
Claim 8
Dependent Claim
59 words
The process of claim 1 wherein (a) the water-polyvinyl chloride slurry contains from about 20 to about 60 weight % polyvinyl chloride and from about 0.1 to about 5 weight % unreacted vinyl chloride and (b) the amount of alkali metal sulfite or carbonate is from about 0.001 to about 1% by weight based on the water-polyvinyl chloride slurry.
Claim 9
Dependent Claim
10 words
The process of claim 7 wherein sodium sulfite is used.
Claim 10
Dependent Claim
10 words
The process of claim 7 wherein sodium carbonate is used.
Claim 11
Dependent Claim
10 words
The process of claim 7 wherein potassium sulfite is used.
Claim 12
Dependent Claim
10 words
The process of claim 7 wherein potassium carbonate is used.
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) | 1979-08-17 | 1980-02-16 | 1980-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-17 | 1984-02-16 | 1984-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-17 | 1988-02-16 | 1988-08-17 | $7700.00 | Window Closed / Lapsed |