GB960499A - Finishing of leather - Google Patents

Abstract

Leather is dressed with a dispersion or solution of a copolymer prepared from olefinically unsaturated compounds which include between 0,5 to 25% of monomers of the general formula: <FORM:0960499/B1-B2/1> in which formulae R1 and R2, which may be the same or different, represent hydrogen atoms, or alkyl radicals containing from 1 to 6 carbon atoms, or aryl radicals, R3 represents a saturated or unsaturated aliphatic hydrocarbon radical containing from 1 to 8 carbon atoms, R4 and R5, which may be the same or different, represent hydrogen atoms, alkyl radicals containing from 1 to 6 carbon atoms or aryl radicals, and R6 and R7, which may be the same or different, represent alkyl radicals preferably containing 1 to 5 carbon atoms, cycloalkyl radicals, aralkyl radicals, or radicals which together with the adjacent nitrogen atom form a heterocyclic ring system. The olefinically unsaturated monomers include 2-10% of monomers of formula I and/or formula II. As compounds of general formula I the reaction product of acryl and methacryl amides with aliphatic alcohols of 1-8 carbon atoms are employed. As compounds of formula II those prepared from (a) formaldehyde, (b) acryl or methacrylamide, and (c) aliphatic secondary amines, the alkyl groups present containing up to 5 carbon atoms, are employed. A copolymer may be used in which the olefinically unsaturated monomers include from 1 to 10% by weight of acrylic acid, methacrylic acid, acrylamide and/or methacrylamide. A copolymer may be used in which the olefinically unsaturated monomers comprise more than 40% of acrylic and/or methacrylic acid esters, 1-10% of acrylic acid and/or methacrylc acid, and 0,5-20% of monomers of the formulae I and/or II. The copolmers are prepared by copolymerization in the presence of anionic, cationic and/or non-ionic emulsifiers. The compound of formula I employed may be methacrylamide methylol methyl ether and this is used in an amount between 2 and 10%. The compound of formula II may be the reaction product of methacrylamide, formaldehyde and dimethylamine or morpholine. Examples of copolymerizable olefinically unsaturated monomers are given. The emulsion polymerization may be activated by addition of organic and inorganic per-compounds, e.g. redox catalysts, or radical forming substance. The coating may contain thickeners, plasticizers, emulsifiers, matting agents, dyestuffs, polyamide dispersions, urea- and melamine-formaldehyde resins, and colloids, e.g. polyvinyl alcohol, partially saponified polyvinyl esters, cellulose ethers and derivatives thereof. Specifications 792,874 and 898,967 are referred to.