Epoxy phosphate ester resin, its production and coating composition containing the resin

• US 5,389,704 A
• Filed: 07/15/1993
• Issued: 02/14/1995
• Est. Priority Date: 12/16/1991
• Status: Expired due to Fees

• Current Assignee: The Dow Chemical Company (Dow, Inc.)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Yabu, Yoshimitsu
• Primary Examiner(s): Marquis, Melvyn I.
• Assistant Examiner(s): Aylward, D.
• Application Number:
  US08/090,027
• Time in Patent Office: 579 Days
• Field of Search: 528/89, 528/108, 528/398, 523/433, 523/451, 523/414, 523/406, 523/409
• US Class Current: 523/406
• CPC Class Codes: C08G 59/1422 containing phosphorus
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 2666/18 Polyesters or polycarbonates according to C08L67/00 - C08L69/00; Derivatives thereof
• CPC Class Codes: C09D 163/00 Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins

Abstract

The present invention provides a process for preparing an epoxy phosphate ester resin, which comprises (1) reacting an epoxy resin having an average of greater than one vicinal epoxy group with a phosphoric acid source material to obtain an epoxy phosphate ester; and (2) further reacting the obtained epoxy phosphate ester with a phosphoric acid source material. The present invention provides epoxy phosphate ester resins obtained by the above process, which exhibit good water-solubility. The coating compositions containing such epoxy phosphate ester resin show good coating properties such as good corrosion resistance, chemical resistance, heat resistance and flexibility.

Claims

1. A process for preparing an epoxy phosphate ester resin, which comprises (1) reacting an epoxy resin having an average of greater than one vicinal epoxy group with a phosphoric acid source material selected from the group consisting of 100 percent phosphoric acid, a semi-hydrate of phosphoric acid, a polymeric phosphoric acid, a partial anhydride of phosphoric acid, pyrophosphoric acid, orthophosphoric acid, triphosphoric acid, superphosphoric acid and a mixture thereof to obtain an epoxy phosphate ester;

and (2) then adding additional phosphoric acid source material to the epoxy phosphate ester obtained in step (1); and

(3) further reacting the epoxy phosphate ester obtained in step (1) with the additional phosphoric acid source material.

2. A process according to claim 1, wherein in the first reaction the epoxy resin is reacted with a phosphoric acid source material in an amount to provide from about 0.2 to about 0.4 hydroxyl group per epoxy group;

and in the second reaction the obtained epoxy phosphate ester is reacted with a phosphoric acid source material in an amount to provide from about 0.05 to about 0.4 hydroxyl group per epoxy group.

3. A process according to claim 1, wherein each of the first and second reaction are carried out at 50°

C. to 150°

C. for a period of from 1 to 110 minutes.

4. A process according to claim 1, which further comprises subjecting the epoxy phosphate ester resin obtained to hydrolysis treatment with water to produce an epoxy phosphate monoester;

and then subjecting the obtained epoxy phosphate monoester to neutralization treatment.

5. A process according to claim 1, wherein the epoxy resin is a glycidyl ether of bisphenol A, glycidyl ether of bisphenol K, glycidyl ether of bisphenol F, glycidyl ether of bisphenol S, glycidyl ether of bisphenol AD or a mixture thereof.

6. An epoxy phosphate ester resin prepared by the process of claim 1.

7. A coating composition comprising:

(a) the epoxy phosphate ester resin of claim 6;

(b) an acrylic resin or a polyester resin, miscible with the epoxy phosphate ester resin;

(c) at least one curing agent; and

(d) water.

8. A coating composition comprising:

(a) the epoxy phosphate ester resin of claim 6;

(b) an acrylic resin or a polyester resin, miscible with the epoxy phosphate ester resin;

(c) at least one curing agent; and

(d) an organic solvent.

9. The epoxy phosphate ester resin of claim 6 which is water-soluble.