Non-chrome tanning method
US4784664A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 1986 |
| Grant date | Nov 15, 1988 |
| Priority date | — |
| Expiry date | Jun 24, 2006 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC14C3/02
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The present process yields superior leather materials from limed hides, without the use of chromium salts, by combining a series of essential method steps in a sequence which yields leather having a "chrome" character. The present chromium-free tanning process includes the method steps of pretanning a hide with a chromium-free tan until its shrinkage temperature is about 170.degree. to 185.degree. F., submerging the hide in an acidic brine, having a pH between 2.5 and 3.5, and adding (in sequence, and in amounts sufficient to yield specified concentrations of each) pretanning agents, syntans, vegetable extracts, neutralizing agents and retanning and finishing agents, all of which are free from chromium. This method of pretanning, tanning and retanning a hide with a specified sequence of particular concentrations of chromium-free reagents yields a leather product having the characteristics of chrome-tanned leather and which demonstrates superior shrink resistance, resilience and flexural strength. The resultant leather product has particular utility when incorporated into durable, weather-resistant footwear such as military shoes and boots, but is likewise suitable for use in other …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.