DE1292286B - Coating agent for the anodic coating of electrically conductive workpieces by electrophoresis - Google Patents

Description

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The invention relates to a coating agent commercially available epoxy resin with a medium for anodic plating, electrically conductive molecular weights of about 370 to 450 have been used with Workpieces mixed by electrophoresis on the basis of 320 kg of linseed oil fatty acids, and 1000 ecm of aqueous dispersions of salts carboxyl-xylene were placed in a reaction vessel and on grouped resins. According to the invention, the 5 200 ° C for IV2 hours heated and then on Dispersion salts of polyethylene glycol with mol- 230 ° C heated for 4 hours during which Kular weight over 200 esterified, at about 53 ecm of water were removed and a resin 160 ° C produced reaction products one was formed.

Acid number above about 30 from trimellitic acid stage 2. The reaction mixture after stage 1

anhydride and linseed oil fatty acid modified epoxy 10 was cooled to 160 ° C,
resins. , Stage 3. The reaction product of stage 1 was

For the production 'of' by electrophoresis. The 85kg of trimellitic anhydride added to which paints to be applied is the use-of - 'cties the'"lowered temperature at the moment. The resins are known. It is at this paint temperature was brought back to 160 ° C and coatings around synthetic resin compounds that held until the reaction mixture became clear with amines and / or ammonia or weak. "-"'

Alkalis are neutralized. The resin compounds stage 4. The clear reaction mixture after

are soluble or can be diluted with water. Stage 3 was 100 kg of polyethylene glycol. An alkyd resin with a molecular weight of 200 is used as the resin. This essential constituent, an addition product of an ao constituent, was heated to 160 ° C. until the ethylene dicarboxylic acid, for example maleic acid, and / or acid number of about 36.5 was reached, when its anhydride is then complete. The alkyd resins are condensed and 132 kg of methyl ethyl ketone addition products of polyalcohol on the one hand and poly are set on them. ; ..:.:; . ;;; .. .-. x \ :. \
carboxylic acids on the other hand, the polyalcohol being stage 5. The reaction mixture after stage 4

Among other things, polyethylene glycol can be used 25 with 150 kg of red iron oxide on level 6 according to can. These resins can optionally be ground with Fett-Hegman, and it was 85 kg. Triiso acid modified. propanolamine addedv " ^{! i} · -

In the case of the coating agents according to the invention, level 6 was then used.

First a linseed oil fatty acid-modified resin is formed from the material after stage 5 with 3800 g, which is then produced with trimellitic anhydride in re-ionized water and stirring '
action brought and finally with polyethylene glycol:; An electrical coating bath "with a pH value" is esterified. The latter, therefore, serves for the esterification of. 7.0 and with. 3.4 weight percent dyes of a modified epoxy resin and not for the formation of the above-described formation of a condensation product of Polycarbonate ··, emulsion diluted with deionized water, acid and polyalcohol, as is the case with the known .35. The electrophoretic precipitation of the emulsified alkyd resin is the case. The different type of color was brought into a steel, polished coating medium according to the invention made, which served as the cathode of the lent advantages with it. electric precipitation cell.

The advantages over the known resin compounds, which were immersed in the bath, were electrical connections consist in the fact that it is charged 4 ° and served as the anodes of the cell. The lighter electrophoretically pulling down by the scattering force was carried out at 37 ° C and a voltage of 450 V, and the other time that the increased. A more evenly applied coatings are particularly durable, deposits of about 0.025 mm thick are obtained, which results in good leakage properties. That and the workpieces were removed from the bath, modified epoxy resin according to the invention is in the 45 The coatings of the panels were then extremely stable in an aqueous bath and therefore easily baked for 15 minutes at 200 ° C. Then dispersible. The panels have been sprayed with salt on all surfaces of the metal, including objects as measured by ASTM test method no. B 117, and savings or irregularly designed surfaces lasted 250 hours. Other panels were used to attach the covers. They form a 5o 250, 300 and -350 V plated,
highly corrosive resistance. In addition to these intrinsic In order to make use of the scattering power of this formulation

The coating agent has properties that make it a test, a test with three plates was customary Withstands sanding processes, and the ones that led. This experiment was carried out with 370 V below Another coating of the same or different use of a device, which can be achieved by assembling it together can be applied. When riveting three right-angled Salt spray processes result in the coatings being made entirely from a single rivet. Every sheet extremely high test (ASTM) of 250 hours measured 75 x 200 mm, and the sheets were and more. composed that, seen from the side, the middle

The invention is explained in more detail using the following examples, the lere rectangle was covered by two plates. ⁶ ° about 0.0625 mm maximum from the riveted base

line diverged. The covered area of the middle plate is a measure of the spread of the

Example I Formulation under the conditions used. at

of this formulation, 75% of the middle plate 6g was coated, to a depth of about

An electric plating paint became 0.025 mm within one minute after application prepared in the following manner: generation of a voltage which has a high scattering power

Stage 1. 800 kg of a resin consisting of one means.

Example II

There have been effective colors for electrophoretic Coatings prepared as in the previous example except that the polyethylene glycols possessed an average molecular weight of 400 and 600 instead of a molecular weight of 200 for the polyethylene glycol of the previous example.

The emulsion was diluted to make a coating bath as in the previous example formed, and was then applied in the same way to metallic workpieces.

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Claims (1)

Claim: Coating agent for the anodic coating of electrically conductive workpieces by electrophoresis based on aqueous dispersions of salts of resins containing carboxyl groups, characterized in that they contain salts of molecular weight polyethylene glycol over 200 esterified reaction products with an acid number produced at about 160 ° C of over about 30 epoxy resins modified from trimellitic anhydride and linseed oil fatty acid contain.