Electrodepositable coating composition

Patent metadata

Field	Value
Publication number	US-10947408-B2
Application number	US-201816019590-A
Country	US
Kind code	B2
Filing date	Jun 27, 2018
Priority date	Jun 27, 2018
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

The present invention is directed to a phosphated epoxy resin comprising at least one terminal group comprising a phosphorous atom covalently bonded to the resin by a carbon-phosphorous bond or by a phosphoester linkage; and at least one carbamate functional group. The present invention is also directed towards aqueous resinous dispersions comprising the phosphated epoxy resin, methods of coating a substrate, coated substrates, and methods of making a phosphated epoxy resin.

First claim

We claim:

1. A phosphated epoxy resin comprising:
at least one terminal group comprising a phosphorous atom covalently bonded to the resin by a carbon-phosphorous bond or by a phosphoester linkage; and
at least one carbamate functional group;
wherein the terminal group of the phosphated epoxy resin comprises the structure:

wherein R 1 and R 2 each independently represent hydrogen, hydroxyl, an alkyl radical, an aryl radical, or a phosphoester group, and
wherein the phosphated epoxy resin comprises at least one constitutional unit A comprising the structure:

wherein R 1 and R 2 each independently represent hydrogen, an alkyl radical or an aryl radical.

2. The phosphated epoxy resin of claim 1 , wherein the phosphated epoxy resin further comprises at least one constitutional unit B comprising the structure:

wherein R 1 and R 2 each independently represent hydrogen, an alkyl radical or an aryl radical.

3. The phosphated epoxy resin of claim 2 , wherein the ratio of constitutional unit A to constitutional unit B is from 1:20 to 20:1.

4. A method of making the phosphated epoxy resin of claim 1 , the method comprising:
reacting an epoxy resin comprising at least one terminal epoxide functional group and at least one pendant hydroxyl functional group with a molecule comprising an isocyanato functional group and a carbamate functional group, wherein the pendant hydroxyl functional group and isocyanato functional group react to form a urethane linkage, whereby the molecule is incorporated into the epoxy resin to form a carbamate-functional epoxy resin; and
further reacting the carbamate-functional epoxy resin with a phosphoric acid, a phosphonic acid, a phosphinic acid, or combinations thereof, wherein the at least one terminal epoxide functional group of the carbamate-functional epoxy resin reacts with an acid group of the phosphoric acid or phosphonic acid, whereby the phosphoric acid and/or the phosphonic acid is incorporated into the carbamate-functional epoxy resin to form the phosphated epoxy resin comprising at least one carbamate functional group.

5. The method of claim 4 , wherein the phosphated epoxy resin comprising at least one carbamate functional group is neutralized with a base.

6. An aqueous resinous dispersion comprising:
(a) the phosphated epoxy resin of claim 1 ; and
(b) a carbamate-functional oligomer comprising at least two carbamate functional groups.

7. An aqueous resinous dispersion comprising:
(a) a phosphated epoxy resin comprising:
(i) at least one terminal group comprising a phosphorous atom covalently bonded to the resin by a carbon-phosphorous bond or by a phosphoester linkage; and
(ii) at least one carbamate functional group; and

(b) a curing agent;
wherein the terminal group of the phosphated epoxy resin comprises the structure:

wherein R 1 and R 2 each independently represent hydrogen, hydroxyl, an alkyl radical, an aryl radical, or a phosphoester group, and
wherein the phosphated epoxy resin comprises at least one constitutional unit A comprising the structure:

wherein R 1 and R 2 each independently represent hydrogen, an alkyl radical or an aryl radical.

8. The aqueous resinous dispersion of claim 7 , wherein the terminal group comprises phosphate, organophosphate, phosphonate, organophosphonate, phosphinate, organophosphinate, or combinations thereof.

9. The aqueous resinous dispersion of claim 7 , wherein the phosphated epoxy resin comprises the structure:

wherein R 1 , R 2 , R 3 and R 4 each independently represent hydrogen, hydroxyl, an alkyl radical, an aryl radical, or a phosphoester group, and R represents the residue of an epoxy functional polymer comprising at least one carbamate functional group.

10. The aqueous resinous dispersion of claim 7 , wherein the phosphated epoxy resin is substantially free of pendent groups comprising a phosphorous atom covalently bonded to the resin by a carbon-phosphorous bond or by a phosphoester linkage.

11. The aqueous resinous dispersion of claim 7 , wherein the phosphated epoxy resin comprises at least one pendent group comprising the carbamate functional group, the pendent group comprising the structure:

wherein R represents remainder of the phosphated epoxy resin.

12. The aqueous resinous dispersion of claim 7 , wherein the phosphated epoxy resin further comprises at least one constitutional unit B comprising the structure:

wherein R 1 and R 2 each independently represent hydrogen, an alkyl radical or an aryl radical.

13. The aqueous resinous dispersion of claim 12 , wherein the ratio of constitutional unit A to constitutional unit B is from 1:20 to 20:1.

14. The aqueous resinous dispersion of claim 7 , wherein the phosphated epoxy resin comprises the structure:

wherein m is 1 to 2,000 and n is 0 to 2,000; R 1 and R 2 each independently represent hydrogen, an alkyl radical or an aryl radical; R 3 and R 4 each independently represent hydrogen, hydroxyl, an alkyl radical, an aryl radical, or a phosphoester group.

15. The aqueous resinous dispersion of claim 7 , wherein the curing agent comprises at least two functional groups reactive with carbamate functional groups.

16. The aqueous resinous dispersion of claim 7 , wherein the curing agent comprises an aminoplast resin, a phenoplast resin, a blocked polyisocyanate, or combinations thereof.

17. The aqueous resinous dispersion of claim 7 , wherein the aqueous resinous dispersion is substantially free of metal-containing catalysts.

18. The aqueous resinous dispersion of claim 7 , further comprising a carbamate-functional oligomer comprising at least two carbamate functional groups.

19. The aqueous resinous dispersion of claim 18 , wherein the carbamate-functional oligomer comprises the structure:

20. A method of coating a substrate comprising electrophoretically depositing the aqueous resinous dispersion of claim 7 onto the substrate to form a coating on the substrate.

21. The method of claim 20 , wherein the coating deposited from the aqueous resinous dispersion of claim 7 cures at a bake temperature of 250° F. in 60 minutes or less, as measured by surviving at least 25 double acetone rubs according to Double Acetone Rub Test Method.

22. The method of claim 20 , wherein the coating deposited from the aqueous resinous dispersion of claim 7 is hydrolytically stable, as determined by the Hydrolytic Stability Test Method.

Assignees

• Prc Desoto Int Inc

Inventors

• Dacko Christopher A
• Mayo Michael A
• Mccollum Gregory J
• Peffer Robin M
• Lee Se Ryeon

Classifications

• B64G1/226

  Special coatings for spacecraft · CPC title

• C09D163/00 Primary

  Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins · CPC title

• C08K5/205

  Compounds containing [IMAGE cpc-sch-C08K-1010.gif] groups, e.g. carbamates · CPC title

• C08L2201/54

  Aqueous solutions or dispersions · CPC title

• C08K5/521

  Esters of phosphoric acids, e.g. of H3PO4 · CPC title