Method for coating substrates, preferably of metal

• US 6,413,642 B1
• Filed: 08/06/1999
• Issued: 07/02/2002
• Est. Priority Date: 12/04/1996
• Status: Expired due to Fees

• Current Assignee: BASF Coatings AG (BASF SE)
• Original Assignee: BASF Coatings AG (BASF SE)
• Inventors: Jandel, Lothar, Clausen-Meiring, Ulrike, Bürstinghaus, Rainer, Grobe Brinkhaus, Karl-Heinz, Drescher, Dorothe, Ott, Günther, Wegner, Egon, Bremser, Wolfgang, Wilke, Guido
• Primary Examiner(s): Copenheaver, Blaine
• Assistant Examiner(s): Paulraj, Christopher
• Application Number:
  US09/319,378
• Time in Patent Office: 1,061 Days
• Field of Search: 427/407.1, 427/409, 427/412.1, 428/414, 428/413, 428/418, 523/414, 204/181
• US Class Current: 428/418
• CPC Class Codes: B05D 2252/02 of indefinite length
• CPC Class Codes: B05D 7/16 using synthetic lacquers or varnishes
• CPC Class Codes: B05D 7/52 Two layers
• CPC Class Codes: C08G 18/581 Reaction products of epoxy resins with less than equivalent amounts of compounds containing active hydrogen added before or during the reaction with the isocyanate component with amines C08G18/584
• CPC Class Codes: C08G 18/792 formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates
• CPC Class Codes: C09D 163/00 Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
• CPC Class Codes: C09D 175/04 Polyurethanes
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31515 As intermediate layer
• CPC Class Codes: Y10T 428/31529 Next to metal

Abstract

The present invention relates to a method of coating substrates, preferably of metal, by cleaning the substrate surface, applying, if desired, an organic and/or inorganic pretreatment composition, applying a primer, applying a coating material by spraying, dipping, knifecoating, rollercoating or brushing, the coating material comprising an amine-modified epoxy resin and a crosslinking agent suitable for crosslinking.

Claims

1. A method of coil coating a substrate comprising

cleaning the substrate surface,

applying a primer, and

applying a topcoat by a method selected from the group consisting of spraying, dipping, knifecoating, rollercoating and brushing,

wherein the primer comprises an amine-modified epoxy resin and an oligomeric polyol and has a viscosity of from 50 to 150 seconds in a DIN4 cup.

2. The method of claim 1, wherein the amine-modified epoxy resin comprises the reaction product of

A) one or more polyepoxides selected from the group consisting of modified polyepoxides, nonmodified polyepoxides, and mixtures thereof,

B) one or more members selected from the group consisting of primary amines, secondary amines, the salts of primary amines, the salts of secondary amines, salts of tertiary amines and mixtures thereof, and

optionally, C) one or more members selected from the group consisting of polyols, polycarboxylic acids, polyamines, polysulfides, and mixtures thereof.

3. The method of claim 1, wherein the primer is present in an organically or aqueously diluted form.

4. The method of claim 3, wherein the amine-modified epoxy resin comprises the reaction product of an epoxy resin which has been modified with one or more members selected from the group consisting of a monophenol compound, a thiol compound, amine, diols, dicarboxylic acids, and mixtures thereof.

5. A method according to claim 1, wherein the oligomeric polyol comprises a polyether alcohol.

6. A method according to claim 1, wherein the oligomeric polyol is selected from the group consisting of polypropylene glycol, polyethylene glycol, and polypropylene/polyethylene mixed diols.

7. A method according to claim 1, wherein the oligomeric polyol is selected from the group consisting of ethoxylated bisphenol A, propoxylated bisphenol A, ethoxylated/propoxylated bisphenol A, ethoxylated monophenols, propoxylated monophenols, ethoxylated/propoxylated monophenols, and mixtures thereof.

8. A method according to claim 1, wherein the oligomeric polyol comprises polycaprolactone.

9. A method according to claim 1, wherein the primer further comprises a crosslinking agent, and the primer comprises up to 30% by weight of the oligomeric polyol based on the total weight of the amine modified epoxy resin, the oligomeric polyol, and the crosslinker.

15. A substrate according to claim 5, wherein the oligomeric polyol comprises a polyether alcohol.

10. A coil-coated substrate comprising a substrate and one or more coats, the coil-coated substrate prepared by a coil-coating method comprising

cleaning the substrate surface,

applying a primer coat

optionally applying a topcoat or a plurality of topcoats by a method selected from the group consisting of spraying, dipping, knifecoating, rollercoating and brushing, and

baking the substrate,

wherein the primer comprises an amine-modified epoxy resin and an oligomeric polyol and has a viscosity of from 50 to 150 seconds in a DIN4 cup.

11. The coated substrate of claim 10, wherein the amine-modified epoxy resin comprises the reaction product of

A) one or more polyepoxides selected from the group consisting of modified polyepoxides, nonmodified polyepoxides, and mixtures thereof,

B) one or more members selected from the group consisting of primary amines, secondary amines, the salts of primary amines, the salts of secondary amines, salts of tertiary amines and mixtures thereof, and

optionally, C) one or more members selected from the group consisting of polyols, polycarboxylic acids, polyamines, polysulfides, and mixtures thereof.

12. The coated substrate of claim 10, wherein the primer comprises one or more amine-modified epoxy resins in an organically or aqueously diluted form.

13. The coated substrate of claim 12, wherein the amine-modified epoxy resin comprises the reaction product of an epoxy resin which has been modified with one or more members selected from the group consisting of a monophenol compound, a thiol compound, amine, diols, dicarboxylic acids, and mixtures thereof.

14. The coated substrate of claim 13, wherein component A comprises the result of reacting

a) a diepoxide compound or a mixture of diepoxide compounds having an epoxide equivalent weight of less than 2000 with

b) at least one phenolic hydroxyl- or thiol-containing compound that reacts monofunctionally with the epoxide groups under the given reaction conditions,

wherein components (a) and (b) are employed in a molar ratio of from 10:

1 to 1;

1, and the reaction of component (a) with component (b) is conducted at a temperature of from 100 to 190°

C.

16. A substrate according to claim 10, wherein the oligomeric polyol is selected from the group consisting of polypropylene glycol, polyethylene glycol, and polypropylene/polyethylene mixed diols.

17. A substrate according to claim 10, wherein the oligomeric polyol is selected from the group consisting of ethoxylated bisphenol A, propoxylated bisphenol A, ethoxylated/propoxylated bisphenol A, ethoxylated monophenols, propoxylated monophenols, ethoxylated/propoxylated monophenols, and mixtures thereof.

18. A substrate according to claim 10, wherein the oligomeric polyol comprises polycaprolactone.

19. A substrate according to claim 10, wherein the primer further comprises a crosslinking agent, and the primer comprises up to 30% by weight of the oligomeric polyol based on the total weight of the amine modified epoxy resin, the oligomeric polyol, and the crosslinker.

20. A method of producing an article, wherein the article is selected from the group consisting of construction accessories, furniture, instrument paneling, vehicle bodies, domestic appliances, and lamp casings, comprising the steps of

providing a substrate, and

coating the substrate with a process comprising the steps of

cleaning the substrate surface,

applying a primer, and

applying a topcoat by a method selected from the group consisting of spraying, dipping, knifecoating, rollercoating and brushing,

wherein the primer comprises an amine-modified epoxy resin and an oligomeric polyol and has a viscosity of from 50 to 150 seconds in a DIN4 cup.