It would be desirable to have a liquid epoxy resin that provides increased corrosion resistance, additional formulating time or pot-life, sprayable or paintable at ambient temperatures which maintains or exceeds the coating performance of conventional aromatic polyether polyepoxy resins.
Bowditch in U.S. Pat. No. 4,507,461 discloses epoxy resins prepared from the reaction of epichlorohydrin with the reaction product of a compound containing aromatic hydroxyl groups and an alkylene oxide so as to produce an aromatic compound containing aliphatic hydroxyl groups. The epichlorohydrin is reacted in amounts which provides a stoichiometric excess of 8 to 10 percent of the epichlorohydrin in relation to the equivalents of hydroxyl groups (this amounts to a ratio of moles of epichlorohydrin per aliphatic hydroxyl group of from 1.08:1 to 1.1:1). These epoxy resins are useful as diluents for other epoxy resins and in coating compositions. While coatings can be prepared from mixtures of these epoxy resins disclosed by Bowditch and epoxy resins prepared from epichlorohydrin and compounds having aromatic hydroxyl groups, the resultant coatings have less chemical resistance when coating compositions containing these epoxy resins are coated onto such substrates as treated or untreated steel or treated or untreated aluminum as compared to the chemical resistance of such substrates coated with like composition but without the epoxy resin disclosed by Bowditch.
It would therefore be desirable to have available low viscosity epoxy resins which when blended with other epoxy resins and formulated into a coating composition would result in a coating which provides better chemical resistance than that which is provided by the resins disclosed by Bowditch.
The present invention provides an epoxy resin which when blended with another epoxy resin and formulated into a coating composition provides cured coatings having an improvement in chemical resistance to acids. In addition, the present invention also provides a composition that allows for additional working time for the formulator resulting in greater flexibility and control to the applicator.