Abstract: Disazo compounds based on 4,4'-diaminodiphenyl compounds contain not less than 50% by weight of a disazo compound of the general formulaA--N.dbd.N--Z--N.dbd.N--B (I)where Z is a radical of an unsubstituted of symmetrically substituted diphenylene, A is a radical of a coupling component of a 1-phenylpyrazolone or of an acetoacetarylide, where the phenyl and the aryl radical is substituted by sulfo or carboxyl groups, and B is a radical of a coupling component based on 1-phenylpyrazolone or acetoacetarylide, which are free of sulfo and/or carboxyl groups.The disazo compounds can be obtained by coupling the tetrazotized diamine H.sub.2 N--Z--NH.sub.2 to the coupling component AH containing an acidic group in a medium containing a mineral acid, and then coupling the product to BH in a buffered medium (pH about 4).The novel disazo compounds are suitable as additives to pigments, in particular azo and disazo pigments, for improving the transparency and heat stability of the pigment particles, and the flow behavior.

Abstract: The invention relates to cathodically depositable aqueous electropaints which contain cationic amine-modified epoxy resins and are pigmented with electroconductive carbon black and which, on deposition and crosslinking, provide electrophoretically overcoatable coatings and contain as electroconductive carbon black a carbon black having an iodine absorption of 870-930 mg/g, a specific surface area (BET/N.sub.2) of 850-1,000 m.sup.2 /g, a pore volume (DBP) of 330-390 ml/100 g and an average particle size of 25-35 nm in an amount of 1.5 to 5.1% by weight - based on total solids.

Abstract: A binder which is water-dilutable on protonation with acid and obtainable by a reaction of(A) an epoxy resin having an average molecular weight of from 300 to 6,000 and on average from 1.5 to 3.0 epoxide groups per molecule and(B) from 20 to 30 mol %, based on the amount of epoxide groups present in epoxy resin (A), of one or more secondary amine and/or alkanolamine of up to 40 carbon atomsand subsequent reaction with(C) a copolymer which is based on butadiene and acrylonitrile and contains primary and/or secondary amino groups, the amount of (C) being so dimensioned that the number of primary and secondary amino groups corresponds to from 1 to 50 mol % of the epoxide groups present in the epoxy resin (A), and also(D) with one or more primary and/or secondary amine to convert any epoxide groups still present, is usedin particular for cathodic electrocoating.

Abstract: Novel zinc, lead or zinc/lead salts of carboxylic acids of the formula ##STR1## where Y is --CO-- or --SO.sub.2 --, X is H or --NO.sub.2 and n is 1 or 2. The salts, in particular the basic salts of (I), are useful corrosion-inhibitors for coating systems, especially for aqueous or water-dilutable systems.

Abstract: The invention relates to a process for coating an electrically conductive substrate, the said substrate being immersed in an aqueous bath based on a cationic synthetic resin binder which is at least in part neutralized with acids and contains amino and/or hydroxyl groups. The said bath contains a mixture of crosslinking agents as well as pigments, fillers, corrosion inhibitors, paint auxiliary substances, and, if appropriate, catalysts, as well as organic solvents in an amount of up to 15% by weight based on the total weight of the coating, the said substrate being cathodically connected. By the action of direct current, a film is deposited on the substrate, after which the said substrate is removed from the bath and the film is cured by stoving, the mixture of crosslinking agents comprising at least two crosslinking agents of different reactivities based on activated esters and/or polyisocyanates blocked by different blocking agents.

Abstract: The invention relates to an aqueous cathodic electrocoating material which contains a synthetic resin binder containing amino and/or hydroxyl groups and capable of being rendered water-soluble by the addition of an acid. The synthetic resin binder contains a mixture of crosslinking agents, as well as pigments, fillers, corrosion inhibitors, surface coating assistants, if appropriate catalysts, and organic solvents in an amount of up to 15% by weight, based on the total weight of the coating material. The mixture of crosslinking agents consists of at least two crosslinking agents which possess different reactivities and are based on activated esters and/or polyisocyanates blocked with different blocking agents. Different reactivities means that the crosslinking reactions begin at temperatures which are at least 10.degree. C. apart. The crosslinking reagent which reacts first is present in an amount of from 15 to 60 mol %, based on the mixture of crosslinking agents.

Abstract: Binders which are rendered water-dilutable by protonation with an acid, a process for their preparation and their use.These binders are obtainable by reacting a(A) Reaction product of a(a) carboxyl-containing component, consisting of a(a1) carboxyl-containing butadiene/acrylonitrile copolymer having a molecular weight of from 500 to 8,000, if necessary as a mixture with(a2) a dicarboxylic acid which differs from (a1) and, if appropriate,(a3) a monocarboxylic acid and(b) a diprimary and/or primary/secondary amine, with the proviso that from 0.7 to 5 moles of the said amine are used per mole of carboxyl groups of component (a),with one or more(B) epoxy resins having a mean molecular weight from 300 to 6,000 and containing on average from 1.5 to 3.0 epoxide groups per molecule and, if required,(C) an aliphatic or cycloaliphatic secondary amine.In combination with a crosslinking agent, they are useful as coating materials, in particular for cathodic electrocoating.