Waterborne shop primer

Patent metadata

Field	Value
Publication number	US-10633546-B2
Application number	US-201615019640-A
Country	US
Kind code	B2
Filing date	Feb 9, 2016
Priority date	Aug 23, 2013
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

A coating system for application to metal components prior to assembly or fabrication into large metal objects is described. The system includes a composition comprising a water-dispersible polymer component, a crosslinking agent, and a conductive material. When applied to a metal substrate, the coating system is weldable and provides optimal corrosion resistance during fabrication or assembly.

First claim

What is claimed is:

1. A method of making a corrosion-resistant metal article, comprising
providing an article having a metal substrate;
applying thereon a coating composition comprising, based on the total weight of the coating composition:
a two-component composition including
about 10 to 20 wt % of an epoxy polymer component having number average molecular weight (M n ) of 800 to 1500 and EEW of about 200 to about 500; and
about 1 to 5 wt % of a polyamide crosslinker having amine equivalent weight is about 250; and
about 15 to 25 wt % of an aqueous carrier in which the binder is dispersed;
about 1 to 5 wt % of a conductive material;
about 1 to 5 wt % of a pigment;
about 1 to 5 wt % of a first solvent;
about 5 to 10 wt % of a second solvent; and
about 30 to 40% wt % of non-reactive zinc; and

drying the coating to form a corrosion-resistant film at dry film thickness of about 2 to 20 μm on the metal substrate, wherein the film emits no harmful byproducts on welding.

2. The method of claim 1 , wherein the conductive material is a conductive pigment selected from calcium, cobalt, nickel, iron, copper, carbonaceous material, or mixtures thereof.

3. The method of claim 2 , wherein the carbonaceous material is selected from carbon black, graphite, or carbon fiber.

4. The method of claim 1 , wherein the coating composition further includes a corrosion inhibitor.

5. The method of claim 4 , wherein the corrosion inhibitor is selected from aluminum triphosphate, barium triphosphate, calcium phosphosilicate, calcium silicate and mixtures thereof.

6. The coating method of claim 1 , wherein the corrosion-resistant film formed by drying is weldable.

7. The coating method of claim 1 , wherein the metal substrate comprises steel, iron, aluminum, zinc, or alloys of iron, aluminum, or zinc.

8. The method of claim 1 , wherein the composition is substantially free of elemental or metallic zinc.

9. The method of claim 1 , wherein the composition includes less than about 1 weight percent of an anti-settling component.

10. The coating method of claim 1 , wherein the metal substrate is a component of a prefabricated article requiring temporary corrosion protection during manufacture.

11. The coating method of claim 1 , wherein the metal substrate is a component or part of a shipping container.

12. The coating method of claim 1 , wherein the corrosion-resistant film formed by drying the composition is heat-resistant in a humid environment.

13. The method of claim 1 , wherein the polyamide component is water-dispersible.

Assignees

• Valspar Sourcing Inc
• Sherwin Williams Co

Inventors

• Black David

Classifications

• C09D177/00

  Coating compositions based on polyamides obtained by reactions forming a carboxylic amide link in the main chain (based on polyhydrazides C09D179/06; based on polyamide-imides C09D179/08); Coating compositions based on derivatives of such polymers · CPC title

• C09D163/00

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

• C09D5/24

  Electrically-conducting paints {(conductive materials H01B1/00)} · CPC title

• C08G59/54

  Amino amides> · CPC title

• C09D5/10

  containing metal dust · CPC title