US4435221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for cleaning metal surfaces of poly(arylene sulfide) deposits
Assignee: Phillips Petroleum Co
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Filing: 1982-07-30
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Granted: 1984-03-06
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Expires: 2002-07-30
Abstract
Abstract A process for the removal of poly(arylene sulfide) deposits is provided which comprises contacting said deposits with a solution comprising an alkali metal hydrosulfide in a lactam. In addition, a process for the cleaning of metal parts having poly(arylene sulfide) deposits is provided by contacting the metal parts in the manner as described immediately above, contacting the metal part with a lower alkyl alcohol, washing said metal part with water, drying said metal part, contacting the dried part with concentrated HNO 3 followed by water washing and drying.
Inventors
- 👤 Ronald D. Mathis
- 👤 Jerry O. Reed
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:16
CPC Classifications
D; D01; D01D; D01D4/00; D01D4/04; B; B29; B29C; B29C48/00; B29C48/25; B29C48/27; C; C08; C08G; C08G85/00; C08G85/008; C09; C09D; C09D9/00; B29C48/03; B29C48/05
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
73 words
A process for the removal of poly(arylene sulfide) deposits from metal surfaces comprising contacting said deposits with a cleaning solution, consisting essentially of at least one alkali metal hydrosulfide in a lactam of the general formula ##STR2## where R is hydrogen or an alkyl radical having from 1 to 5 carbon atoms and n is an integer from 5 to 7 at a temperature and for a time sufficient to remove said deposits.
Claim 2
Dependent Claim
73 words
A process for the removal of poly(arylene sulfide) deposits from metal surfaces comprising contacting said deposits with a cleaning solution, consisting essentially of at least one alkali metal hydrosulfide in a lactam of the general formula ##STR2## where R is hydrogen or an alkyl radical having from 1 to 5 carbon atoms and n is an integer from 5 to 7 at a temperature and for a time sufficient to remove said deposits.
Claim 3
Dependent Claim
13 words
A process according to claim 1 wherein said poly(arylene sulfide) is poly(phenylene sulfide).
Claim 4
Dependent Claim
23 words
A process according to claim 1 wherein said solution comprises from about 0.5 to about 25.0 weight percent of sodium hydrosulfide in ε-caprolactam.
Claim 5
Dependent Claim
40 words
A process according to claim 1 wherein said contacting is carried out at a temperature from about 200° C. up to the boiling point of said lactam for a period of time from about 0.5 hours to about 24 hours.
Claim 6
Dependent Claim
22 words
A process according to claim 1 wherein said metal surfaces are thereafter treated by contacting said surfaces with a lower alkyl alcohol.
Claim 7
Dependent Claim
35 words
A process according to claim 5 wherein said metal surfaces are thereafter treated by washing said surfaces with water, drying the metal surfaces, followed by contacting the dried metal surface with concentrated HNO 3 .
Claim 8
Dependent Claim
114 words
A process for cleaning metal surfaces having poly(arylene sulfide) deposits thereon comprising: (a) contacting said metal parts with a cleaning solution, consisting essentially of at least one alkali metal hydrosulfide in a lactam of the general formula ##STR3## where R is hydrogen or an alkyl radical having from 1 to 5 carbon atoms and n is an integer from 5 to 7 at a temperature and for a time sufficient to remove said deposits; (b) thereafter contacting the metal part with a lower alkyl alcohol; (c) washing the metal part with water; (d) drying the metal part; and (e) contacting the dried metal part with concentrated HNO 3 followed by water washing and drying.
Claim 9
Dependent Claim
114 words
A process for cleaning metal surfaces having poly(arylene sulfide) deposits thereon comprising: (a) contacting said metal parts with a cleaning solution, consisting essentially of at least one alkali metal hydrosulfide in a lactam of the general formula ##STR3## where R is hydrogen or an alkyl radical having from 1 to 5 carbon atoms and n is an integer from 5 to 7 at a temperature and for a time sufficient to remove said deposits; (b) thereafter contacting the metal part with a lower alkyl alcohol; (c) washing the metal part with water; (d) drying the metal part; and (e) contacting the dried metal part with concentrated HNO 3 followed by water washing and drying.
Claim 10
Dependent Claim
13 words
A process according to claim 7 wherein said poly(arylene sulfide) is poly(phenylene sulfide).
Claim 11
Dependent Claim
23 words
A process according to claim 7 wherein said solution comprises from about 0.5 to about 25.0 weight percent of sodium hydrosulfide in ε-caprolactam.
Claim 12
Dependent Claim
30 words
A process according to claim 7 wherein said contacting is carried out at a temperature above about 200° C. for a time from about 0.5 hours to about 24 hours.
References Cited (Backward Citations)
US4032362A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-06 | 1987-09-05 | 1988-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-06 | 1991-09-05 | 1992-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-06 | 1995-09-05 | 1996-03-06 | $7700.00 | Window Closed / Lapsed |