Abstract:
The invention relates to a process for the preparation of aqueous dispersions to be further processed to electrocoating paints with baking temperatures below 160° C. and baking times of ≦30 minutes, which dispersions contain modified epoxide-amine adducts as binders and polyisocyanates blocked by amino groups as crosslinking agents. In this process, polyepoxides and compounds which contain one or more, preferably 2, hydroxyl groups per molecule are converted at higher temperatures and in the presence of catalysts to epoxide-containing intermediates. A solvent or a mixture of solvents is then added with external cooling and the solution is then caused to boil under reflux, if necessary by application of a vacuum, until the temperature of the solution drops to 95° C. to 20° C. Amines are then added onto the epoxide groups which are still present in a free state in the epoxide resin and either a dispersion is prepared after the addition of the crosslinking agent by adding a water-acid mixture or the products are first dispersed and the crosslinking agent is added subsequently.
Abstract:
Aqueous electrocoating baths containing synthetic resins capable of deposition on the cathode, and a process for coating electrically conducting substratesThe invention relates to aqueous electrocoating baths containing synthetic resins capable of deposition on the cathode. The electrocoating baths according to the invention are characterized in that they contain a homopolymer or copolymer of an alkyl vinyl ether of the general formula CH.sub.2 =CH--O--R wherein R represents an alkyl radical having 2 to 4 C atoms.
Abstract:
The invention relates to aqueous electrocoating baths for cathodic paint deposition which contain, as cathodically depositable binders, modified epoxide-amine adducts and are prepared by reacting, in the presence of basic amine catalysts,(1)(A) polyepoxides with(B) compounds which contain, per molecule, one or more, preferably 2, hydroxyl groups bonded to aromatic and/or (cyclo)aliphatic molecular fragments, to form epoxide group-containing intermediates, and(2) by subsequently reacting these intermediates, if appropriate, with further conventional modifiers and finally with(C) primary and/or secondary (poly)amines or their salts and/or salts of tertiary amines, the resultant reaction products being neutralized with acids, if appropriate, dispersed in an aqueous medium and these dispersions further processed by well-known methods to form electrocoating baths. The electrocoating baths according to the invention are distinguished by the fact that the basic amine catalyst which catalyzes the reaction between the components (A) and (B) is neutralized, prior to further reaction of the intermediates formed from the components (A) and (B), with a Bronsted acid having a pK.sub.s value of the first stage of dissociation, measured at 20.degree. C., below 3.7, preferably below 3.5.
Abstract:
The invention relates to water-dilutable binders for cationic electrocoating finishes. For the preparation of the binders, a di-epoxide compound, together with at least one mono-epoxide compound if desired, is converted by a polyaddition, carried out at 100.degree. to 195.degree. C. and initiated by a monofunctionally reacting initiator carrying either an alcoholic OH group, a phenolic OH group or an SH group, to form an epoxy resin which then subsequently is modified with(A) primary and/or secondary amines or their salts and/or the salt of a tertiary amine, a sulfide/acid mixture or a phosphine/acid mixture and with, if desired,(B) a polyfunctional alcohol, a polycarboxylic acid, a polysulfide or a polyphenol.
Abstract:
This application discloses a synthetic resin based on alcohol-modified polyepoxides. The synthetic resin can be prepared by reacting a diepoxide, or a mixture of diepoxides, having an epoxide equivalent weight of less than about 500, with compounds with a hydroxyl group, which is reactive towards epoxide groups, in a molar ratio from about 2:1 to about 7:6 at temperatures from about 100.degree. C. to about 180.degree. C. in an organic solvent free of hydroxyl groups. The synthetic resin has terminal epoxide gorups and a mean molecular weight from about 400 to about 5000.
Abstract:
The heat-hardenable binder mixture based on organic resins comprises an organic resin having primary and/or secondary and, if appropriate, also additional tertiary amino groups and a cross-linking agent based on an organic compound containing at least 2 carbalkoxymethyl groups. The binder mixture can additionally contain pigments, fillers, cross-linking catalysts, corrosion inhibitors and further finish auxiliaries. The binder mixture is used in a process for preparing coatings by applying a coating agent in the form of a film to a substrate and subsequently hardening the film by baking.
Abstract:
The invention relates to a synthetic resin based on an acrylate copolymer containing epoxide groups and having a number average molecular weight of 1,000 to 30,000. The acrylate copolymer comprises (a) 20 to 90% by weight of an alkyl acrylate having 1 to 18 carbon atoms in the alkyl radical and/or a methacrylate having 1 to 20 carbon atoms in the alkyl radical, (b) 5 to 40% by weight of a hydroxyalkyl acrylate and/or methacrylate and (c) 5 to 40% by weight of glycidyl acrylate and/or methacrylate and/or one other olefinically unsaturated, polymerizable compound carrying an epoxide group, the total amount of components a, b and c being 100%. The hydroxyl groups of the acrylate copolymer have been reacted before or after the copolymerization was carried out at least partially with a partially blocked diisocyanate and/or polyisocyanate.
Abstract:
The invention relates to a polyether urethane of the general formula ##STR1## wherein R.sup.1 denotes H or an alkyd (sic) radical of 1 to 8 carbon atoms,R.sup.2 denotes an alkylene radical of 2 to 10 carbon atoms or a cycloalkylene radical of 6 to 20 carbon atoms or an arylene radical of 6 to 20 carbon atoms,R.sup.3, R.sup.4 denote an optionally substituted alkyl radical of 1 to 8 carbon atoms or a joint ring whose members are R.sup.3 and R.sup.4,n denotes 2 to 1800m denotes 1 to 15.The invention further relates to a process for its preparation, to a flow-out agent for water-borne paints and to the use of the polyether urethanes as flow-out agents in water-borne, cathodically depositable electro-coating paints.
Abstract:
The invention relates to water-dispersible binders for cationic electrocoating finishes, which binders are reaction products of (A) low molecular weight epoxide resins containing aromatic groups and having an epoxide equivalent weight of below 375, (B) aliphatic and/or alicyclic polyfunctional alcohols and/or carboxylic acids having a molecular weight of below 350, (C) if appropriate up to 60% by weight, relative to the total binder, of polyfunctional alcohols, carboxylic acids and/or SH compounds having a molecular weight of 500-5,000 and (D) primary, secondary and/or tertiary amines and/or salts thereof or a sulfide/acid mixture or a phosphine/acid mixture, the reaction product of A and B containing 10-45% of aromatic groups, calculated as the phenylene group. By means of the binders, a higher layer thickness is obtained in electrocoating.
Abstract:
The invention relates to a process for the preparation of aqueous dispersions to be further processed to electrocoating paints with baking temperatures below 160.degree. C. and baking times.ltoreq.30 minutes, which dispersions contain modified epoxide-amine adducts as binders and polyisocyanates blocked by hydroxyl groups as cross-linking agents.In this process polyepoxides and compounds containing one or more, preferably 2, hydroxyl groups per molecule are reacted at elevated temperatures in the presence of catalysts to furnish epoxide-containing intermediates.A solvent or a mixture of solvents is then added with external cooling ahd the solution is boiled under reflux, if necessary in vacuo, until the temperature of the solution drops to 95.degree. C. to 20.degree. C.Amines are then added onto the epoxide groups which are still present in a free state in the epoxy resin and a dispersion is prepared by adding a water/acid mixture after adding the crosslinking agent or the dispersion is first prepared and the crosslinking agent is added subsequently.