US3953307A
Expired / Lapsed
US
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Vat dye reduction process for use in a dyeing plant for textile processing
Assignee: Bombay Textile Research Associates
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Filing: 1974-07-31
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Granted: 1976-04-27
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Expires: 1994-07-31
Abstract
Abstract A process for compensating for reduction in the reducing effect caused by atmospheric oxygen or dissolved oxygen in an aqueous reducingsolution of sodium hydrosulphite employed in a vat dye reduction process wherein the vat dye is reduced and fixed on textile materials by the reducing action of the aqueous alkaline reducing solution, which process comprises generating hydrogen in said reducing solution, which hydrogen combines with the dissociation products of the sodium hydrosulphite to form a powerful reducing species with relatively high redox potential, by carrying out electrolysis of the aqueous alkaline solution.
Inventors
- 👤 Shashikant Dattatraya Supanekar
- 👤 Erach Hormasji Daruwalla
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:50
CPC Classifications
C; C01; C01D; C01D5/00; D; D06; D06P; D06P1/00; D06P1/22; D06P5/00; D06P5/20; D06P5/2016
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
132 words
A process for compensating for reduction in the reducing effect caused by atmospheric oxygen or dissolved oxygen in an aqueous reducing solution of sodium hydrosulphite employed in the vat dye reduction process wherein vat dye is reduced and fixed on textile materials by the reducing action of the aqueous alkaline reducing solution, which process comprises continuously or intermittently forming sulphoxylic acid as a powerful reducing species with relatively high redox potential in said aqueous reducing solution to maintain the reducing strength of said solution, by continuously or intermittently carrying out electrolysis directly through said solution employing a relatively large negative electrode submerged in said solution and a relatively small positive electrode submerged or on the surface of said solution, said negative and positive electrodes being operatively connected to a direct current source.
Claim 2
Dependent Claim
132 words
A process for compensating for reduction in the reducing effect caused by atmospheric oxygen or dissolved oxygen in an aqueous reducing solution of sodium hydrosulphite employed in the vat dye reduction process wherein vat dye is reduced and fixed on textile materials by the reducing action of the aqueous alkaline reducing solution, which process comprises continuously or intermittently forming sulphoxylic acid as a powerful reducing species with relatively high redox potential in said aqueous reducing solution to maintain the reducing strength of said solution, by continuously or intermittently carrying out electrolysis directly through said solution employing a relatively large negative electrode submerged in said solution and a relatively small positive electrode submerged or on the surface of said solution, said negative and positive electrodes being operatively connected to a direct current source.
Claim 3
Dependent Claim
27 words
A process as claimed in claim 1, wherein said aqueous alkaline reducing solution contains sodium hydrosulphite in admixture with sodium bisulphite, sodium sulphite, sodium sulphide or dextrin.
Claim 4
Dependent Claim
57 words
A process as claimed in claim 2, wherein said electrolysis is effected in the aqueous alkaline reducing solution stored in a feeder tank of a continuous dyeing plant, said reducing solution being fed thereafter to a developing trough of said dyeing plant for reducing and fixing vat dyes on textile material continually passing through said developing trough.
Claim 5
Dependent Claim
21 words
A process as claimed in claim 2, wherein said electrolysis is effected in a jigger in the case of batch dyeing.
Claim 6
Dependent Claim
57 words
A process as claimed in claim 1, wherein said electrolysis is effected in the aqueous alkaline reducing solution stored in a feeder tank of a continuous dyeing plant, said reducing solution being fed thereafter to a developing trough of said dyeing plant for reducing and fixing vat dyes on textile material continually passing through said developing trough.
Claim 7
Dependent Claim
21 words
A process as claimed in claim 1, wherein said electrolysis is effected in a jigger in the case of batch dyeing.
References Cited (Backward Citations)
US2371145A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-27 | 1979-10-27 | 1980-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-27 | 1983-10-27 | 1984-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-27 | 1987-10-27 | 1988-04-27 | $7700.00 | Window Closed / Lapsed |