Patent US2729534A successfully refreshed from Google Patents.
US2729534A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lignin-tanned leather and process for making same
Assignee: Individual
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Filing: 1955-09-07
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Granted: 1956-01-03
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Expires: 1975-09-07
Abstract
No abstract record available.
Inventors
- 👤 Ehrensperger Hans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:47
CPC Classifications
C; C14; C14C; C14C3/00; C14C3/02; C14C3/08; C14C3/24
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
162 words
A PROCESS OF PRODUCING LEATHER COMPRISING SOAKING LEATHER STOCK IN AN AQUEOUS SOLUTION OF LIGNIN-CONTAINING MATERIAL SELECTED FROM THE GROUP CONSISTING OF SULFPHONIC ACID-LIGNIN AND ALKALI LIGNIN, SAID AQUEOUS SOLUTION HAVING A PH ABOVE ABOUT 3.5 IN THE CASE OF SULPHONIC ACID-LIGNIN, SAID AQUEOUS SOLUTION HAVING A PH ABOVE ABOUT 6.5 IN THE CASE OF ALKALI LIGNIN WHEN SAID ALKALI LIGNIN IS KRAFT LIGNIN, AND SAID AQUEOUS SOLUTION HAVING A PH ABOVE ABOUT 8.5 IN THE CASE OF ALKALI LIGNIN WHEN SAID ALKALI LIGNIN IS NOT KRAFT LIGNIN, AND A WATER-SOLUBLE CONDENSATION PRODUCT OF A WATER-SOLUBLE ALDEHYDE WITH A MEMBER OF THE GROUP CONSISTING OF MONOMERIC DOUBLE ACID AMIDES AND AMINO TRIAZINES, THEN ACIDFYING THE SOLUTION WITHOUT HEATING TO PRECIPITATE THE ACTIVE SUBSTANCE IN SITU AS A WATER-INSOLUBLE PRECIPITATE, SAID ACIDIFICATION BEING TO A PH BELOW ABOUT 2.5 WHEN SAID LIGNIN MATERIAL IS A SULPHONIC ACID LIGNIN AND TO A PH BELOW ABOUT 5 WHEN SAID LIGNIN MATERIAL IS AN ALKALI LIGNIN.
Claim 2
Dependent Claim
162 words
A PROCESS OF PRODUCING LEATHER COMPRISING SOAKING LEATHER STOCK IN AN AQUEOUS SOLUTION OF LIGNIN-CONTAINING MATERIAL SELECTED FROM THE GROUP CONSISTING OF SULFPHONIC ACID-LIGNIN AND ALKALI LIGNIN, SAID AQUEOUS SOLUTION HAVING A PH ABOVE ABOUT 3.5 IN THE CASE OF SULPHONIC ACID-LIGNIN, SAID AQUEOUS SOLUTION HAVING A PH ABOVE ABOUT 6.5 IN THE CASE OF ALKALI LIGNIN WHEN SAID ALKALI LIGNIN IS KRAFT LIGNIN, AND SAID AQUEOUS SOLUTION HAVING A PH ABOVE ABOUT 8.5 IN THE CASE OF ALKALI LIGNIN WHEN SAID ALKALI LIGNIN IS NOT KRAFT LIGNIN, AND A WATER-SOLUBLE CONDENSATION PRODUCT OF A WATER-SOLUBLE ALDEHYDE WITH A MEMBER OF THE GROUP CONSISTING OF MONOMERIC DOUBLE ACID AMIDES AND AMINO TRIAZINES, THEN ACIDFYING THE SOLUTION WITHOUT HEATING TO PRECIPITATE THE ACTIVE SUBSTANCE IN SITU AS A WATER-INSOLUBLE PRECIPITATE, SAID ACIDIFICATION BEING TO A PH BELOW ABOUT 2.5 WHEN SAID LIGNIN MATERIAL IS A SULPHONIC ACID LIGNIN AND TO A PH BELOW ABOUT 5 WHEN SAID LIGNIN MATERIAL IS AN ALKALI LIGNIN.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-01-02 | 1959-07-04 | 1960-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-01-02 | 1963-07-04 | 1964-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-01-02 | 1967-07-04 | 1968-01-03 | $7700.00 | Window Closed / Lapsed |