Title: Cataphoretic electrodeposition baths containing water-soluble lead salts

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Claims: We claim:

1. An improved method of electrocoating an electrically conductive article serving as a cathode in an electrical circuit comprising an anode, said cathode and an electrodeposition bath comprising an aqueous dispersion of a cationic electrodepositable resin, the improvement comprising the addition to said electrodeposition bath of 50 to 3000 parts per million based on total bath weight of a water-soluble lead compound in an amount sufficient such that it will improve the corrosion resistance of a ferrous metal article which is cathodically electrocoated in said electrodeposition bath, the lead compound being soluble to the extent of at least one percent by weight in water having a pH of 7.

2. The method of claim 1 in which the water-soluble lead compound is added in an amount sufficient to provide from 100 to 3000 parts per million lead.

3. The method of claim 1 in which the water-soluble lead compound is the lead salt of an organic acid.

4. The method of claim 3 in which the water-soluble lead salt is selected from the class consisting of lead acetate and lead lactate.

5. The method of claim 1 in which the electroconductive article is a ferrous metal article.

6. The method of claim 5 in which the electroconductive article is an untreated ferrous metal article.
Other info:

Inventors: Zwack, Robert R. (New Kensington, PA, US)
Jerabek, Robert D. (Glenshaw, PA, US)

Application Number: 785154
Filing Date: 1977-04-06
Publication_date: 1978-09-19
Assignee: PPG Industries, Inc. (Pittsburgh, PA)
Primary Class(es): 204/499
Other Classes:
US Patent Ref:

3682814	Aug, 1972	Gilchrist	204/181.
3692714	Sep, 1972	Keyman et al.	204/181.

Other Refs:
Primary Examiner: Williams, Howard S.
Assistant Examiner:
Attorney: Uhl; William J.