US4875900A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of treating leather
Assignee: Individual
•
Filing: 1987-09-22
•
Granted: 1989-10-24
•
Expires: 2007-09-22
Abstract
Abstract The invention relates to a method for treatment of leather for improving the chrome exhaustion and various other properties. The method consists in treating the leather with a dispersion microcrystalline polyamide or polyester. Such a treatment is carried out at the stage of tanning, rechroming, retanning or dyeing.
Inventors
- 👤 Vir B. Singh
- 👤 Kanniah N. G. K. Moorthy
- 👤 Pushpendar K. Kaushik
- 👤 Hariharan Sankarasub-Ramanian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:56
CPC Classifications
C; C14; C14C; C14C9/00; C14C3/00; C14C3/02; C14C3/28; D; D06; D06P; D06P1/00; D06P1/44; D06P1/52; D06P1/5264; D06P1/5271; D06P1/5278
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
124 words
An improved process for the chemical treatment of animal skins and hides to obtain leather by tanning, rechroming, retanning and dyeing, each of said steps of tanning, rechroming, retanning and dyeing being carried out in the presence of its respective treating liquor the improved process comprising preparing an aqueous dispersion of microcrystalline polymer and adding the prepared aqueous dispersion to the treating liquor such that at least one of said steps of tanning, rechroming, retanning and dyeing is carried out in the presence of the respective liquor with said aqueous dispersion added thereto to improve chrome absorption, said microcrystalline polymer having particles of size up to 2 microns and selected from a polyamide or polyester and maintaining a pH level between 2 to 8.
Claim 2
Dependent Claim
124 words
An improved process for the chemical treatment of animal skins and hides to obtain leather by tanning, rechroming, retanning and dyeing, each of said steps of tanning, rechroming, retanning and dyeing being carried out in the presence of its respective treating liquor the improved process comprising preparing an aqueous dispersion of microcrystalline polymer and adding the prepared aqueous dispersion to the treating liquor such that at least one of said steps of tanning, rechroming, retanning and dyeing is carried out in the presence of the respective liquor with said aqueous dispersion added thereto to improve chrome absorption, said microcrystalline polymer having particles of size up to 2 microns and selected from a polyamide or polyester and maintaining a pH level between 2 to 8.
Claim 3
Dependent Claim
23 words
An improved process as claimed in claim wherein the aqueous dispersion of said polyamide or polyester has solid content of up to 50%.
Claim 4
Dependent Claim
21 words
An improved process as claimed in claim 1 wherein the treatment is carried out at a pH between 2 to 4.5.
Claim 5
Dependent Claim
21 words
An improved process as claimed in claim 2 wherein the treatment is carried out at a pH between 2 to 4.5.
Claim 6
Dependent Claim
30 words
An improved process as claimed in claim 3 wherein the said microcrystalline polymer or polyester is obtained by subjecting chips of the polymer material to attrition in an attrition mill.
Claim 7
Dependent Claim
29 words
An improved process as claimed in claim 4 wherein said microcrystalline polymer or polyester is obtained by subjecting chips of the polymer material to attrition in an attrition mill.
References Cited (Backward Citations)
GB720505A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-23 | 1993-04-24 | 1993-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-23 | 1997-04-24 | 1997-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-23 | 2001-04-24 | 2001-10-24 | $7700.00 | Window Closed / Lapsed |