Chrome-free leather retanning

Patent metadata

Field	Value
Publication number	US-9970070-B2
Application number	US-201414514582-A
Country	US
Kind code	B2
Filing date	Oct 15, 2014
Priority date	Oct 18, 2013
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A method for forming chrome-free retanned leather including: (a) contacting wet white with from 1% to 8%, by solids weight, based on the wet weight of wet white, retanning agent selected from the group consisting of: i) an aqueous emulsion polymer including, as copolymerized units, from 2% to 35%, by weight, based on the weight of the emulsion polymer, ethylenically-unsaturated monomer bearing at least one epoxy group, the emulsion polymer having a weight average molecular weight of from 2,000 to 100,000; ii) a compound selected from the group comprising piperazine, piperazine hydrates, salts of piperazine, and combinations thereof; and iii) combinations of i) and ii); (b) heating the contacted wet white; and (c) drying the contacted, heated wet white is provided. The present application also relates to chrome-free retanned leather formed by the method of the invention.

First claim

We claim:

1. A method for forming chrome-free retanned leather comprising:
(a) contacting wet white with from 1% to 8%, by solids weight, based on the wet weight of wet white, retanning agent selected from the group consisting of: i) an aqueous emulsion polymer comprising, as copolymerized units, from 2% to 35%, by weight, based on the weight of said emulsion polymer, ethylenically-unsaturated monomer bearing at least one epoxy group, said emulsion polymer having a weight average molecular weight of from 2,000 to 100,000;
ii) a compound selected from the group comprising piperazine, piperazine hydrates, salts of piperazine, and combinations thereof; and
iii) combinations of i) and ii);
(b) heating said contacted wet white; and
(c) drying said contacted, heated wet white.

2. The method of claim 1 wherein said ethylenically-unsaturated monomer bearing at least one epoxy group is selected from the group consisting of glycidyl (meth)acrylate, allyl glycidyl ether, and mixtures thereof.

3. The method of claim 1 wherein said compound is a mixture of piperazine phosphate and piperazine pyrophosphate.

4. A chrome-free retanned leather formed by the method of claim 1 .

Assignees

• Rohm & Haas

Inventors

• Li Caiyun
• Su Fengyi
• Xue Yin

Classifications

• C14C3/22 Primary

  using polymerisation products · CPC title

• C14C3/26

  using other organic substances, containing halogen · CPC title

• C14C3/16

  using aliphatic aldehydes · CPC title

• C14C3/28

  Multi-step processes · CPC title