Patent GB-705335-A (GB)
Title: Process for dyeing leather
IPC: D06P3/32
Filed: 1951-12-20
Abstract: Condensation products are made from 4 or more mols of an alkylene oxide and a compound containing a primary or secondary amino group, or else a tertiary amino group together with an alcohol group. Preferred products contain an aliphatic or alicyclic residue having 8 or more carbon atoms, such as an abietyl group or an alkyl residue of 12 or more carbon atoms.  The process is preferably carried out by adding the alkylene oxide gradually to the amine at 50-200 DEG C. and 2-10 atmospheres.  An alkaline catalyst may be present.  The products may be quarternated, e.g. with dimethyl sulphate.  Examples show the condensation of (1) hydrogenated abietylamine with 10 mols of ethylene oxide; (2) oleylamine with 6 mols of ethylene oxide, and (3) the mono-ester of triethanolamine and coconut fatty acid with 22 mols of ethylene oxide.  A list of suitable amines is given; propylene oxide and glycide may also be used.ALSO:In dyeing leather which has been tanned with a chromium salt alone or in conjunction with another tanning agent free from phenolic hydroxyl groups, the leather is treated before or during dyeing with the reaction product of 4 or more mols of an alkylene oxide with a compound containing a primary or secondary amino group or containing a tertiary amino group and an alcohol group, or a salt of such compound.  A mixture of such products may be used.  Preferably there is present in the compound an aliphatic or alicyclic residue having 8 or more carbon atoms, such as an abietyl group or an alkyl residue of 12 or more carbon atoms.  A list of suitable such compounds and alkylene oxides is given.  The solubility of the products may be increased by quaternation.  When treating leather before dyeing the compounds may be dissolved or dispersed in the usual fat-liquoring or drumming solutions; alternatively the treatment may follow fat-liquoring.  Dyeing may follow immediately or the leather may be dried first.  The auxiliary tanning agents referred to above may be aluminium or zirconium salts or products derived from urea-formaldehyde and melamine-formaldehyde resins.  Dyeing may be carried out with acid, direct or chrome dyes, a list of suitable dyes being given. In the examples, (1) chrome-tanned leather is treated with water containing a sulphonated oil and a condensation product of 10 mols of ethylene oxide with hydrogenated abietylamine; it is then dried and brushed with a solution of Chrome Leather Yellow T containing formic acid; (2) suede leather is fatted with turkey red oil and the condensation product of (1) added; it is then wetted back with ammonia, dyed with Melantherine BH and fixed with formic acid; (3) as in (1) or (2) using the condensation product from 6 mols of ethylene oxide and oleylamine; (4) dry chrome-tanned leather is drummed with a solution of the ethylene oxide condensate of nuclear alkyl-substituted aniline (or salt thereof) and dyed as in (1) or (2); (5) fat-liquored dry chrome leather is brushed with a solution of Chrome Leather Yellow T, the condensation product of (1) and formic acid; (6) suede leather is dyed in a bath containing Chrome Leather Yellow T, ammonia and the condensation product of ethylene oxide with either hydrogenated abietylamine or the mono-ester of triethanolamine with the fatty acid of coconut oil; the dyeing is fixed with formic acid.