Method for coating metal surfaces of substrates and objects coated in accordance with said method

Patent metadata

Field	Value
Publication number	US-10093809-B2
Application number	US-201414902979-A
Country	US
Kind code	B2
Filing date	Jul 10, 2014
Priority date	Jul 10, 2013
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

The invention relates to a method for coating surfaces, to a corresponding coating, and to the use of the objects coated in accordance with said method. The invention relates to a method for coating metal surfaces of substrates, comprising or consisting of the following steps: I. providing a substrate having a cleaned metal surface, II. contacting and coating metal surfaces with an aqueous composition in the form of a dispersion and/or suspension, IX. optionally rinsing the organic coating, and X. drying and/or baking the organic coating or XI. optionally drying the organic coating and coating with a coating composition of the same type or a further coating composition before a drying process and/or baking process, wherein in step II the coating is performed with an aqueous composition in the form of a dispersion and/or suspension containing 2.5 to 45 wt % of at least one non-ionic stabilized binder and 0.1 to 2.0 wt % of a gelling agent, wherein the aqueous composition has a pH value in the range of 0.5 to 7 and forms, with the cations eluted from the metal surface in the pretreatment step and/or during the contacting in step II, a coating based on an ionogenic gel.

First claim

The invention claimed is:

1. Method for coating metallic surfaces of substrates, comprising steps:
I. supplying a substrate metallic surface, the metallic surface being cleaned,
II. contacting and coating the metallic surface with an aqueous composition in the form of a dispersion, suspension or combinations thereof to form an organic coating on the metallic surface, and
III. drying the organic coating, baking the organic coating or combinations thereof,

wherein the aqueous composition of step II contains 2.5 to 45 wt % of at least one nonionically stabilized binder and 0.1 to 2.0 wt % of a gelling agent, and wherein the aqueous composition has a pH in the range of 0.5 to 7 and forms the organic coating based on an ionogenic gel with metal cations dissolved out of the metallic surface during the contacting in step II.

2. The method according to claim 1 , wherein the gelling agent comprises:
a) at least one polysaccharide based on glycogens, amyloses, amylopectins, calloses, agar, algins, alginates, pectins, carrageenan, celluloses, chitins, chitosans, curdlans, dextrans, fructans, collagens, gellan gum, gum arabic, starches, xanthans, gum tragacanth, karayans, tara gum, and glucomannans;
b) at least one anionic polyelectrolyte of natural origin, based on polyamino acids, collagens, polypeptides, and lignins,
c) at least one synthetic anionic polyelectrolyte, based on polyamino acids, polyacrylic acids, polyacrylic acid copolymers, acrylamide copolymers, lignins, polyvinyl sulfonic acid, polycarboxylic acids, polyphosphoric acids, and polystyrenes,
(d) or combinations thereof.

3. The method according to claim 1 , wherein the gelling agent comprises at least one polysaccharide, based on pectins, gellan gum or combinations thereof.

4. The method according to claim 1 , wherein the aqueous composition, the organic coating produced from it, or combinations thereof contains at least one anionic polysaccharide, selected from those with a degree of esterification, amidation or a combination thereof of the carboxyl function in the range of 1 to 75%, based on the total number of alcohol and carboxy groups.

5. The method according to claim 1 , wherein the aqueous composition, the organic coating produced from it, or combinations thereof contain at least one anionic polysaccharide, at least one anionic polyelectrolyte or combinations thereof selected from those having a molecular weight in the range of 500 to 1,000,000 g/mol.

6. The method according to claim 1 , wherein the nonionically stabilized binders are modified with adhesion-promoting adhesive groups, selected from the group consisting of chemical groups of multifunctional epoxies, isocyanates, primary amines, secondary amines, tertiary amines, quaternary amines, amides, imides, imidazoles, formamides, Michael reaction products, carbodiimides, carbenes, cyclic carbenes, cyclocarbonates, multifunctional carboxylic acids, amino acids, nucleic acids, methacrylamides, polyacrylic acids, polyacrylic acid derivatives, polyphenols, polyols having at least one alkyl or aryl radical, caprolactam, phosphoric acids, phosphoric acid esters, epoxy esters, sulfonic acids, sulfonic acid esters, vinyl sulfonic acids, vinyl phosphonic acids, catechol, silanes as well as silanols and/or siloxanes produced from the former, triazines, thiazoles, thiazines, dithiazines, acetals, hemiacetals, quinones, saturated fatty acids, unsaturated fatty acids, alkyds, esters, polyesters, ethers, cyclic ethers, crown ethers, anhydrides as well as acetyl acetones and β-diketo groups, carbonyl groups and hydroxyl groups.

7. The method according to claim 1 , wherein the aqueous composition, the organic coating produced from it or combinations thereof contains at least one complexing agent for the metal cations or a polymer modified for complexing the metal cations.

8. The method according to claim 7 , wherein the at least one complexing agent is selected from the group consisting of those based on maleic acid, alendronic acid, itaconic acid, citraconic acid, mesaconic acid, or one of the anhydrides and hemiesters of these carboxylic acids.

9. The method according to claim 1 , wherein the aqueous composition, the organic coating produced from it or combinations thereof contains at least one type of cations selected from those based on cationic salts selected from the group consisting of melamine salts, nitroso salts, oxonium salts, ammonium salts, salts with quaternary nitrogen cations, salts of ammonium derivatives and salts of Al, B, Ba, Ca, Cr, Co, Cu, Fe, Hf, In, K, Li, Mg, Mn, Mo, Na, Nb, Ni, Pb, Sn, Ta, Ti, V, W, Zn, Zr or combinations thereof.

10. The method according to claim 9 , wherein Al, Cu, Fe, Mg, Zn or a combination thereof are selected as the metal cations that have been dissolved out of the metallic surface, that have been added to the aqueous composition or combinations thereof.

11. The method according to claim 1 , wherein the aqueous composition contains a crosslinking agent selected from the group consisting of: silanes, siloxanes, phenolic resins and amines, in an amount of 0.01 g/L to 50 g/L.

12. The method according to claim 1 , wherein the aqueous composition contains an amino-functionalized silane in an amount of 0.1 g/L to 30 g/L.

13. The method according to claim 1 , wherein the aqueous composition contains complex titanium, zirconium fluorides or a combination thereof in an amount of 0.01 g/L to 100 g/L.

14. The method according to claim 13 , wherein the aqueous composition contains complex titanium, zirconium fluorides or a combination thereof in an amount of 0.1 g/L to 10 g/L.

15. The method according to claim 1 , wherein the aqueous composition contains at least one additive selected from the group, consisting of: defoaming agents, pigments, biocides, dispersion aids, film-forming aids, acidic additives for adjusting the pH, basic additives for adjusting the pH, thickeners and flow control agents.

16. The method according to claim 1 , wherein the organic coating is formed in 0.05 to 20 minutes in an immersion bath and has a dry film thickness in the range of 5 to 100 μm after drying.

17. The method according to claim 1 , wherein step III further comprises rinsing the organic coating before at least one of drying the organic coating, baking the organic coating, and combinations thereof.

18. The method according to claim 1 , wherein step III further comprises drying the organic coating and forming another coating with a similar or additional coating composition before the drying, baking or combinations thereof.

Assignees

• Chemetall Gmbh

Inventors

• Wasserfallen Daniel
• Schwamb Michael
• Frenkel Aliaksandr
• Sotke Vera
• Bremser Wolfgang
• Droll Martin
• Seewald Oliver
• Eilinghoff Ron
• Gerold Stephanie
• Niesen Evgenija
• Schachtsiek Lars
• Traut Manuel

Classifications

• C25D13/04

  with organic material · CPC title

• B05D7/14 Primary

  to metal, e.g. car bodies (involving a chemical reaction between the metal and the coating C23) · CPC title

• C09D5/08 Primary

  Anti-corrosive paints · CPC title

• B05D3/0254

  After-treatment · CPC title

• C09D5/088

  Autophoretic paints · CPC title