Process for cationic electrodeposition of amine acid salt-containing polymers

• US 4,104,147 A
• Filed: 04/19/1977
• Issued: 08/01/1978
• Est. Priority Date: 01/14/1976
• Status: Expired due to Term

• Current Assignee: PPG Industries Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Incorporated (Nouryon BV)
• Inventors: Zwack, Robert R., Marchetti, Joseph R., Jerabek, Robert D.
• Primary Examiner(s): Williams, Howard S.
• Application Number:
  US05/788,706
• Time in Patent Office: 469 Days
• Field of Search: 204/181 C
• US Class Current: 204/502
• CPC Class Codes: C08G 18/0814 containing ammonium groups or groups forming them
• CPC Class Codes: C08G 18/643 Reaction products of epoxy resins with at least equivalent amounts of amines
• CPC Class Codes: C08G 18/8061 masked with compounds having only one group containing active hydrogen
• CPC Class Codes: C08G 59/56 together with other curing agents
• CPC Class Codes: C08K 5/17 Amines; Quaternary ammonium compounds
• CPC Class Codes: C08L 2666/22 Macromolecular compounds not provided for in C08L2666/16 - C08L2666/20
• CPC Class Codes: C08L 63/00 Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• CPC Class Codes: C08L 71/02 Polyalkylene oxides
• CPC Class Codes: C09D 5/4434 characterised by the nature of the epoxy binder

Abstract

Novel, chain-extended adducts formed from reacting high molecular weight polyepoxides and organic polyols containing at least two alcoholic, primary hydroxyls per molecule are disclosed. The chain-extended polyepoxides are adducted with a secondary amine and made dispersible in water with acid. The water-dispersed resins can be applied to a wide variety of substrates by cationic electrodeposition. When compared to resins which are not chain extended, the resins of the invention have higher rupture voltages, improved film-forming properties and deposit as films with improved flexibility.

Claims

1. An improved method for coating a conductive substrate serving as a cathode, which method comprises passing electric current between an anode and said cathode in electrical contact with the water dispersion of a resinous composition, the improvement wherein the resinous composition comprises the reaction product of:

(A) a polyepoxide having a molecular weight of at least 350,

(B) a secondary amine,

(C) a polyester polyol containing at least two alcoholic, primary hydroxyl groups, said polyester polyol being selected from the class consisting of polylactones and polyesters prepared by polyesterification of organic polycarboxylic acids or anhydrides thereof with organic polyols;

said reaction product being dispersible in water with the aid of an acid to provide cationic groups in the resin.

2. The method of claim 1 in which the reaction is conducted in the presence of an added tertiary amine catalyst.

3. The method of claim 1 in which the polyepoxide is first reacted with the secondary amine in a stoichiometric deficiency so as to form a tertiary amine-containing, epoxy-containing adduct which is then further reacted with said polyester polyol to form a chain-extended reaction product.

4. The method of claim 1 in which the polyepoxide is a polyglycidyl ether of a polyphenol having a molecular weight within the range of from about 350 to 2000.

5. The method of claim 4 in which the polyglycidyl ether of the polyphenol is a polyglycidyl ether of a bisphenol having an epoxy equivalent of from about 180 to 1000.

6. The method of claim 1 in which the secondary amine is a dialkyl amine in which the alkyl groups are the same or different and contain from 1 to 4 carbon atoms.

7. The method of claim 6 in which the dialkyl amine is a hydroxyalkyl-containing amine.

8. The method of claim 1 in which the polyester polyol is a polycaprolactone polyol having a molecular weight within the range of 530 to 2000.

9. The method of claim 8 in which the polycaprolactone polyol is formed from ring opening epsilon-caprolactone with ethylene glycol.

10. The method of claim 8 in which the polyamine derivative is a diketimine derived from one mole of diethylene triamine and two moles of methyl isobutyl ketone.

11. The method of claim 1 in which the secondary amine contains a polyamine derivative having at least one ketimine group.

12. The method of claim 1 which contains in the resin molecule active hydrogens and blocked isocyanate groups which are stable at room temperature but are reactive with said active hydrogens at elevated temperature.

13. The method of claim 12 wherein the isocyanate groups and the active hydrogens are present in an equivalent ratio of about 0.1 to 1 blocked isocyanate group for each active hydrogen.

14. The method of claim 1 which contains active hydrogens, said resin taken in further combination with a fully blocked polyisocyanate stable at ordinary room temperature in the presence of said active hydrogen-containing resin but reactive with the active hydrogens of said resin at elevated temperature.

15. The method of claim 14 wherein the isocyanate groups and the active hydrogens are present in an equivalent ratio of about 0.1 to 1 blocked isocyanate group for each active hydrogen.