Edge protection for electrocoat

Patent metadata

Field	Value
Publication number	US-11976210-B2
Application number	US-202017067249-A
Country	US
Kind code	B2
Filing date	Oct 9, 2020
Priority date	Oct 11, 2019
Publication date	May 7, 2024
Grant date	May 7, 2024

Abstract

Aqueous cathodic electrocoat compositions with improved edge protection and methods for preparing such electrocoat compositions are described herein. In an exemplary embodiment, an electrocoat composition includes water; a crosslinkable resin comprising a binder of an epoxy-amine adduct and a crosslinking agent; a neutralizing agent for neutralizing the epoxy amine adduct, wherein the neutralizing agent has a pKa value of greater than 0; and a pigment paste. The pigment paste may comprise silica, barium sulfate or silica and barium sulfate.

First claim

What is claimed is:

1. An aqueous cathodic electrocoat composition having improved edge protection, the composition comprising:
water;
a crosslinkable resin comprising:
a binder, and
a crosslinking agent;

a neutralizing agent for neutralizing the binder, wherein the neutralizing agent comprises a mixture of formic acid, dimethylolpropionic acid (DMPA), lactic acid, and acetic acid; and
a pigment paste,
wherein the water, the crosslinkable resin, and neutralizing agent form an emulsion, and wherein the emulsion comprises:
(A) from about 1 to about 5 mmol of formic acid per 100 grams of solids, from about 1 to about 5 mmol of DMPA per 100 grams of solids, and from about 1 to about 5 mmol of lactic acid per 100 grams of solids;
(B) from about 1 to about 5 mmol of formic acid per 100 grams of solids, from about 1 to about 5 mmol of DMPA per 100 grams of solids, and from about 20 to about 30 mmol of acetic acid per 100 grams of solids;
(C) from about 1 to about 5 mmol of formic acid per 100 grams of solids, from about 1 to about 5 mmol of lactic acid per 100 grams of solids, and from about 20 to about 30 mmol of acetic acid per 100 grams of solids; or
(D) from about 1 to about 5 mmol of DMPA per 100 grams of solids, from about 1 to about 5 mmol of lactic acid per 100 grams of solids, and from about 20 to about 30 mmol of acetic acid per 100 grams of solids.

2. The composition of claim 1 wherein the neutralizing agent consists of acids having a pKa value of greater than 3.

3. The composition of claim 1 wherein the neutralizing agent consists of acids having a pKa value of greater than 3.7.

4. The composition claim 1 wherein the neutralizing agent is substantially free of acids having a pKa value of less than 0.

5. The composition claim 1 wherein the neutralizing agent is substantially free of acids having a pKa value of less than 3.

6. The composition of claim 1 wherein the emulsion comprises:
from about 1 to about 5 mmol of formic acid per 100 grams of solids;
from about 1 to about 5 mmol of DMPA per 100 grams of solids;
from about 1 to about 5 mmol of lactic acid per 100 grams of solids; and
from about 20 to about 30 mmol of acetic acid per 100 grams of solids.

7. The composition of claim 1 wherein the neutralizing agent consists of a mixture of formic acid, dimethylolpropionic acid (DMPA), lactic acid, and acetic acid.

8. The composition of claim 1 wherein the pigment paste includes barium sulfate.

9. The composition of claim 1 wherein the pigment paste includes silica and barium sulfate.

10. The composition of claim 1 wherein:
the neutralizing agent consists of a mixture of formic acid, dimethylolpropionic acid (DMPA), lactic acid, and acetic acid; and
the pigment paste includes silica and barium sulfate.

11. A method for preparing a cathodic electrocoat composition having improved edge protection, the method comprising:
1) Preparing an epoxy amine adduct of an epoxy resin;
2) Preparing a crosslinking agent for the epoxy amine adduct;
3) Blending the epoxy amine adduct with the crosslinking agent;
4) Neutralizing the epoxy amine adduct with a neutralizing agent to form an emulsion; and
5) forming a pigment paste and blending the pigment paste with the neutralized emulsion to form a pigment dispersion; wherein:
the neutralizing agent is comprised of formic acid, dimethylolpropionic acid (DMPA), lactic acid, and acetic acid; and
the emulsion comprises:
from about 1 to about 5 mmol of formic acid per 100 grams of solids;
from about 1 to about 5 mmol of DMPA per 100 grams of solids;
from about 1 to about 5 mmol of lactic acid per 100 grams of solids; and
from about 20 to about 30 mmol of acetic acid per 100 grams of solids.

12. The method of claim 11 wherein:
the neutralizing agent consists of formic acid, dimethylolpropionic acid (DMPA), lactic acid, and acetic acid; and
the emulsion comprises:
from about 2.5 to about 3.5 mmol of formic acid per 100 grams of solids;
from about 3 to about 4 mmol of DMPA per 100 grams of solids;
from about 2 to about 3 mmol of lactic acid per 100 grams of solids; and
from about 22 to about 26 mmol of acetic acid per 100 grams of solids.

13. The method of claim 11 wherein:
the emulsion comprises:
from about 2.5 to about 3.5 mmol of formic acid per 100 grams of solids;
from about 3 to about 4 mmol of DMPA per 100 grams of solids;
from about 2 to about 3 mmol of lactic acid per 100 grams of solids; and
from about 22 to about 26 mmol of acetic acid per 100 grams of solid.

14. The method of claim 11 wherein:
the neutralizing agent consists of acids having a pKa value of greater than 3; and
the pigment paste comprises silica and barium sulfate.

15. The method of claim 11 wherein:
the neutralizing agent consists of acids having a pKa value of from 3.7 to 8; and
the pigment paste comprises silica and barium sulfate.

16. An aqueous cathodic electrocoat composition having improved edge protection, the composition comprising:
water;
a crosslinkable resin comprising:
a binder, and
a crosslinking agent;

a neutralizing agent for neutralizing the binder, wherein the neutralizing agent comprises a mixture of formic acid, dimethylolpropionic acid (DMPA), lactic acid, and acetic acid; and
a pigment paste,

wherein the water, the crosslinkable resin, and neutralizing agent form an emulsion comprising:
from about 1 to about 5 mmol of formic acid per 100 grams of solids;
from about 1 to about 5 mmol of DMPA per 100 grams of solids;
from about 1 to about 5 mmol of lactic acid per 100 grams of solids; and
from about 20 to about 30 mmol of acetic acid per 100 grams of solids.

17. The composition of claim 1 wherein the emulsion comprises:
from about 1 to about 5 mmol of formic acid per 100 grams of solids;
from about 1 to about 5 mmol of DMPA per 100 grams of solids; and
from about 1 to about 5 mmol of lactic acid per 100 grams of solids.

18. The composition of claim 1 wherein the emulsion comprises:
from about 1 to about 5 mmol of formic acid per 100 grams of solids;
from about 1 to about 5 mmol of DMPA per 100 grams of solids; and
from about 20 to about 30 mmol of acetic acid per 100 grams of solids.

19. The composition of claim 1 wherein the emulsion comprises:
from about 1 to about 5 mmol of formic acid per 100 grams of solids;
from about 1 to about 5 mmol of lactic acid per 100 grams of solids; and
from about 20 to about 30 mmol of acetic acid per 100 grams of solids.

20. The composition of claim 1 wherein the emulsion comprises:
from about 1 to about 5 mmol of DMPA per 100 grams of solids;
from about 1 to about 5 mmol of lactic acid per 100 grams of solids; and
from about 20 to about 30 mmol of acetic acid per 100 grams of solids.

Assignees

• Axalta Coating Systems Ip Co

Inventors

• Huesmann Thomas

Classifications

• C09D163/00 Primary

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

• C09D5/443

  Polyepoxides · CPC title

• C09D5/4438

  Binder based on epoxy/amine adducts, i.e. reaction products of polyepoxides with compounds containing amino groups only · CPC title

• C09D5/4492

  containing special additives, e.g. grinding agents · CPC title

• C25D9/02

  with organic materials · CPC title