Double ion exchange of an ultrafiltrate derived from an electrodeposition bath

Claim 2

A method as in claim 2 wherein the resin is an acid-solubilized synthetic polybasic resin.

Claim 3

A method as in claim 2 wherein the electrodeposition bath has been previously utilized to electrocoat articles.

Claim 4

A method as in claim 4 wherein a portion of the solubilized counter-ion is removed from the electrodeposition bath.

Claim 5

A method as in claim 2 wherein the resin is a base-solubilized polyacid resin.

Claim 6

A method as in claim 6 wherein the resin is a synthetic polycarboxylic acid resin.

Claim 7

A method as in claim 7 wherein the ultrafiltration process is operated at a pressure gradient between about 10 and about 150 p.s.i. and wherein the ultrafiltration membrane has a flux rate of at least about 4.5 gallons per square foot per day.

Claim 8

A method as in claim 8 wherein the electrodeposition bath has been previously utilized to electrocoat articles.

Claim 9

A method as in claim 8 wherein the cation exchange resin contains carboxylic acid groups as the functional site.

Claim 10

A method as in claim 8 wherein at least a portion of the excess base is removed from the electrodepositable composition.

Claim 11

A method as in claim 11 wherein the base is potassium hydroxide.

Claim 12

In an electrodeposition process wherein an electrically conductive article is electrocoated in an electrodeposition bath, comprising a synthetic resin ionically dispersed in an aqueous medium, and subsequently rinsed, the improvement comprising subjecting at least a portion of the electrodeposition bath to an ultrafiltration process wherein the ultrafiltration membrane retains said dispersed resin and passes water and solute of substantially lower molecular size than said resin, returning retentate from the ultrafiltration process to the electrodeposition bath, contacting the resultant ultrafiltrate with both an anionic and a cationic ion exchange resin for a time sufficient to remove both anions and cations from said ultrafiltrate, and utilizing the resultant liquid as at least a portion of the rinsing agent.

Claim 13

A method as in claim 13 wherein the electrodeposition bath has been previously utilized to electrocoat articles.

Claim 14

A method as in claim 13 wherein the rinsing is conducted in such a manner that rinsinG removes dragout and the dragout-containing rinse agent returns to the electrodeposition bath.

Claim 15

A method as in claim 13 wherein a portion of the solubilizing counter-ion is removed from the electrodeposition bath.

Claim 16

A method as in claim 13 wherein the resin is an acid-solubilized synthetic polybasic resin.

Claim 17

A method as in claim 13 wherein the resin is a base-solubilized synthetic polyacid resin.

Claim 18

A method as in claim 18 wherein the ultrafiltration process is operated at a pressure gradient between about 10 and about 150 p.s.i. and wherein the ultrafiltration membrane has a flux rate of at least about 4.5 gallons per square foot per day.

Claim 19

A method as in claim 19 wherein the rinsing is conducted in such a manner that rinsing removes dragout and the dragout-containing rinse agent returns to the electrodeposition bath.