Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1993-07-15
1995-02-14
Marquis, Melvyn I.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
523409, 523433, 523451, 528 89, 528108, 528398, C08K 320, C08L 6302
Patent
active
053897048
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a water-soluble epoxy phosphate ester resin which can be used as a water-borne coating material, its production process and a coating composition containing the resin.
BACKGROUND ART
Epoxy resins have been used in a wide variety of applications such as coating applications, for example, because of their superiority in corrosion resistance, chemical resistance and flexibility. In order to improve workability, the epoxy resins are usually diluted with an organic solvent to decrease their viscosities.
Recently, various laws and regulations regarding use of organic solvents, such as organic solvent intoxication prevention regulations and fire regulations, have become more stringent. Because of such regulations, it is desired to make epoxy resins for coating compositions water soluble or water dispersible. Several attempts have been made to modify conventional epoxy resins which per se are not water soluble. For example, self-dispersion type epoxy resins modified with an acrylic resin have been proposed and disclosed in Japanese Patent Application Laid-Open Gazettes Nos. Sho 55-003,481 and Sho 58-198,513.
Further, for simplification of steps, studies have been carried out to make an epoxy resin per se water dispersible. For example, in Japanese Patent Application Laid-Open Gazette No. Hei 2-212,570, an epoxy resin is reacted with phosphoric acid to make the resin water dispersible. However, phosphoric acid has three hydroxyl groups and thus triesters of phosphoric acid are easily formed. For this reason, to obtain an epoxy phosphate ester resin having low viscosity and good dispersion stability, excess amounts of phosphoric acid must be employed. Therefore, unreacted phosphoric acid may remain in the resin product resulting in problems such as blushing of resultant coatings.
Japanese Patent Publication Gazette No. Hei 1-055,299 discloses an epoxy phosphate ester resin prepared by reacting an epoxy resin with phosphoric acid, and then hydrolyzing the phosphoric acid modified epoxy resin for monoesterification. The resultant resin per se can be made water dispersible. However, the resins have unduly large particle size when dispersed in water, resulting in poor dispersion stability. Accordingly, if the amount of organic solvent used is restricted, sufficient dispersion stability cannot be obtained. In particular, in paints prepared using an aromatic epoxy resin, a completely transparent aqueous solution cannot be obtained. In the case of relatively low molecular weight epoxy resins having a weight average molecular weight of 340 to 4,000, there is a problem that they are difficult to hydrolyze and their viscosities increase when dispersed in water.
In view of the deficiencies of the prior art described above, it would be desirable to provide an epoxy phosphate ester resin which exhibits good water-solubility, and its production process.
It would also be desirable to provide a coating composition having good coating properties such as a good anti-rust property and good flexibility.
SUMMARY OF INVENTION
According to the present invention, there is now provided 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.
Another aspect of the present invention pertains to an epoxy phosphate ester resin prepared by the above process.
Another aspect of the present invention relates to a coating composition comprising:
(a) the epoxy phosphate ester resin obtained as above;
(b) an acrylic resin and/or a polyester resin, miscible with the epoxy phosphate ester resin;
(c) at least one curing agent; and
(d) water and/or an organic solvent.
According to the process of the present invention, water-soluble epoxy phosphate ester resins having low viscosity can be obtained while restricting the amount of f
REFERENCES:
patent: 5086094 (1992-02-01), Massingill, Jr.
Aylward D.
Marquis Melvyn I.
The Dow Chemical Company
LandOfFree
Epoxy phosphate ester resin, its production and coating composit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Epoxy phosphate ester resin, its production and coating composit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Epoxy phosphate ester resin, its production and coating composit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-288780