Leather dressing

Abstract

Abstract 1465415 Polyurethane/nitrocellulose compositions BASF AG 23 July 1974 [24 July 1973] 32464/74 Headings C3R and C3F [Also in Division B2] An aqueous dispersion for the final dressing of leather comprises a mixture of (a) an aqueous emulsion of nitrocellulose dissolved in at least one organic solvent and (b) an aqueous polyurethane-ionomer dispersion, the weight ratio of emulsion (a) to dispersion (b) being from 1 : 0À1 to 1 : 10. Optional additives are non- ionic emulsifiers, e.g. ethoxylation products of C 10 -C 30 alcohols and alkyl phenols; and plasticizers, e.g. esters of phthalic acid, sebacic acid and adipic acid, butyl stearate, tributyl phosphate, phenyl phosphate and pressed or blown castor oil. The polyurethane ionomers may be cationic or anionic and may be prepared by reacting the polyurethane with a compound containing either at least one active hydrogen atom or isocyanate group, and at least one group capable of salt formation, e.g. an amino group, which can be neutralized with acids or quaternized. Suitable compounds are hydroxyalkylated aliphatic, cycloaliphatic, aromatic and heterocyclic amines. In the examples aqueous dispersions are prepared by mixing a nitrocellulose emulsion prepared from nitrocellulose, water, organic solvents, ethoxylated castor oil and either (1) castor oil, dioctyl phthalate; or (2) blown castor oil and dibutyl phthalate; or (3) castor oil, dioctyl adipate and nonylbenzene ethoxylate, with a polyurethaneionomer dispersion which is either cationic and which is prepared by first reacting toluene diisocyanate with a polyester of adipic acid, hexane diol and neopentyl glycol and then with N-methyldiethanolamine and 1,4-butane diol, and then with aqueous hydrochloric acid; or which is anionic and which is prepared by first reacting toluene diisocyanate with the above polyester and then with an aqueous solution of ethylenediamine, propane-sulphone and sodium hydroxide. The aqueous dispersions after dilution with water are used to dress real and imitation leathers.

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