US4379708A
Expired / Lapsed
US
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Process for tanning fish skins
Assignee: Individual
•
Filing: 1982-02-18
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Granted: 1983-04-12
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Expires: 2002-02-18
Abstract
Abstract Tanned fish skins of good quality may be obtained by (a) contacting dry fish skins with an aqueous solution of a neutral salt said solution having a pH adjusted into the range 1.5 to 3.5, (b) subjecting said fish skins to a two step tanning operation wherein after said first tanning step said skins are washed at a temperature of not more than 35° C. and the second tanning step is carried out using a more concentrated solution than the first tanning step at a temperature of not less than 35° C. and (c) washing the tanned skins and treating them in an aqueous bath with an anionic grease and then an oil and then with an alkali metal salt of a weak organic acid followed by an alkali to raise the pH to at least 6.
Inventors
- 👤 Norberto O. S. Rego
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:08
CPC Classifications
C; C14; C14C; C14C3/00; C14C3/02; C14C3/28
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
139 words
A process for the production of tanned fish skins which comprises: (a) contacting dry fish skins with an aqueous solution of a neutral salt said solution having a pH adjusted into the range 1.5 to 3.5, (b) subjecting said fish skins to a two step tanning operation wherein after said first tanning step said skins are washed at a temperature of not more than 35° C. and the second tanning step is carried out using a more concentrated solution than the first tanning step at a temperature of not less than 35° C. and (c) washing the tanned skins and treating them in an aqueous aqueous bath with an anionic grease and then an oil and then with an alkali metal salt of a weak organic acid followed by an alkali to raise the pH to at least 6.
Claim 2
Dependent Claim
139 words
A process for the production of tanned fish skins which comprises: (a) contacting dry fish skins with an aqueous solution of a neutral salt said solution having a pH adjusted into the range 1.5 to 3.5, (b) subjecting said fish skins to a two step tanning operation wherein after said first tanning step said skins are washed at a temperature of not more than 35° C. and the second tanning step is carried out using a more concentrated solution than the first tanning step at a temperature of not less than 35° C. and (c) washing the tanned skins and treating them in an aqueous aqueous bath with an anionic grease and then an oil and then with an alkali metal salt of a weak organic acid followed by an alkali to raise the pH to at least 6.
Claim 3
Dependent Claim
25 words
A process according to claim 1 wherein there is used in each of said tanning steps a combination of a chromic salt and a syntan.
Claim 4
Dependent Claim
29 words
A process according to claim 2 wherein in the first of said tanning steps the chromic salt and syntan is used in a concentration of 0.018 to 0.032 grams/liters.
Claim 5
Dependent Claim
31 words
A process according to claim 3 wherein in the second of said tanning steps the chromic salt and syntan is used in a concentration of 0.050 to 0.090 grams per liter.
Claim 6
Dependent Claim
16 words
A process according to claim 2, 3 or 4, wherein said syntan is a sulfone syntan.
Claim 7
Dependent Claim
25 words
A process according to claim 2, 3 or 4, wherein said second tanning step is commenced at a temperature of not less than 50° C.
Claim 8
Dependent Claim
31 words
A process according to claim 1, wherein said first stage of the process, the skins are removed from the bath when it is at a pH of from 2 to 4.
Claim 9
Dependent Claim
27 words
A process according to claim 7, wherein the salt employed is sodium sulfate or sodium chloride and the pH is adjusted by addition of an organic acid.
Claim 10
Dependent Claim
13 words
A process according to claim 8 wherein said organic acid is formic acid.
Claim 11
Dependent Claim
32 words
A process according to claim 2 wherein in stage (a) of the process the salt employed is sodium sulfate or sodium chloride and the pH is adjusted by use of formic acid.
Claim 12
Dependent Claim
23 words
A process according to claim 1 wherein in stage (c) of the process the anionic grease employed is a sulfate or sulfited grease.
Claim 13
Dependent Claim
24 words
A process according to claim 11 wherein after addition of oil the alkali metal salt of a weak organic acid employed is sodium formate.
Claim 14
Dependent Claim
21 words
A process according to claim 12 wherein after addition of sodium formate there is added, as the said alkali, sodium bicarbonate.
Claim 15
Dependent Claim
20 words
A process according to claim 11, 12 or 13 wherein the final pH is in the range 6.5 to 7.
Claim 16
Dependent Claim
26 words
A process according to claim 11, 12 or 13 wherein prior to treatment with an aniomic grease the fish skins are treated with an aniline dye.
Claim 17
Dependent Claim
24 words
A process according to claim 1, 2, 3, 4, 7, 8, 9, 10, 11, 12 or 13 wherein said fish is a teleost fish.
Claim 18
Dependent Claim
18 words
A process according to claim 2, 7, 10 or 11 wherein said fish is of the order Percomorphi.
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) | 1986-04-11 | 1986-10-11 | 1987-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-04-11 | 1990-10-11 | 1991-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-04-11 | 1994-10-11 | 1995-04-12 | $7700.00 | Window Closed / Lapsed |