CROSS-REFERENCE
This application is related to U.S. application Ser. No. 07/928,583now U.S. Pat. No. 5,250,637, to U.S. application Ser. No. 07/928,582, now U.S. Pat. No. 5,288,873, and to U.S. application Ser. No. 07/984,760, now U.S. Pat. No. 5,238,971.
1. Field of the Invention
The invention relates to novel epoxy curing compositions:
1.) an alkyl polyetheramine derived from imidazolidone(hereinafter referred to as IMD).
2.) aminated, alkoxylated derivatives of hydroxyalkyl-2-oxazolidinones.
These novel polyetheramines produce elastomers with good properties. The IMD derivative can be used in combination and the hydroxyalkyl-2-oxazolidinone derivative can be used alone or in combination with known polyalkyleneamine curing agents and reacted with multifunctional epoxy resins to produce systems which possess a level of flexibility and toughness not usually achieved. Due to the unique structure of these amines, which contain cyclic urea, cured systems show increased rigidity, are less extensible, and less resistant to impact than are systems cured with blends of other polyetheramines of equivalent weight.
These novel polyetheramines make it possible to prepare curing agents having a broad range of molecular weights, useful in a variety of epoxy, polyurea, and polyamide applications. The variety of possible combinations and molecular weights can result in a broad range of physical properties in cured products.
2. Related Art
Various strength enhancing additives for epoxy resin systems have been described. These additives, known as "fortifiers", differ considerably in structure from those of the proposed invention. See McLean, et. al., Brit. Poly, J., 15, 66(1983); Garton. et. al., Poly. Eng. & Sci., 27, No. 20, 1620(1987).
The amination of long alkoxylated alkyl chains terminated by hydroxyl groups is well-known in the art.
U.S. Pat. No. 3,654,370 to E. L. Yeakey teaches the amination of polyoxyalkylene polyols to form the corresponding amines by means of ammonia and hydrogen over a catalyst prepared by the reduction of a mixture of the oxides of nickel, copper and chromium. The amination is carried out at a temperature of 150.degree. to 275.degree. C. and 500 to 5000 psig.
U.S. Pat. No. 4,996,294 to Cuscurida et al. teaches a process in which an amine tetrol prepared by oxyalkylation of a propanediol with propylene oxide is catalytically aminated to provide, for example, an aminotetramine. The aminotetramines are useful for preparing polyurea products and as curing agents for epoxy resins.
A number of patents describe catalysts for producing primary or secondary amines. See, for example:
U.S. Pat. No. 4,766,245--(Raney Nickel) to Larkin & Renken; U.S. Pat. Nos. 4,152,345& 4,153,581 to Habermann; U.S. Pat. No. 4,409,399 to H. E. Swift et al.; U.S. Pat. No. 3,390,184 to P. H. Moss et al.; U.S. Pat. No. 3,373,204 to R. A. Hales et al.; U.S. Pat. No. 3,347,926 to J. D. Zech; U.S. Pat. No. 4,014,933 to Boettger et al.; U.S. Pat. No. 4,973,761 to Schoenleben & Mueller; and U.S. Pat. No. 5,003,107 to Zimmerman & Larkin.
It is known in the art that compounds with primary and secondary amine functions can be used as reactive hardeners in epoxy resin formulations employed for protective coatings, electrical embodiments, adhesives, etc. Many of the known polyethyleneamines have been used for such applications. Grayson et al.,ed., Kirk-Othmer Encyclopedia of Chemical Technology, Third Edition, Vol. 7, p. 593.