Epoxy hydantoin-based

Epoxy resins based on glycidylation of bisphenols, cresol and phenol novolacs, polycarboxylic acids, polyols, amines, and aminophenols have been long known. Epoxidized linear and cyclic olefins have also been used as specialty epoxy resins. More recently, glycidylated heterocycles have been introduced, initially as specialty resins promising improved resistance to weathering. One heterocycle in particular, the hydantoin ring, has become of particular interest as an epoxy substrate (J ). 

Table I lists typical properties of a baker s dozen of these resins, produced by typical direct preparations, without extensive purification. Overall, the viscosities of these resins were quite low, particularly by comparison to the well known general purpose epoxy resins based on the diglycidyl ether of bisphenol A (DGEBA). The more shielded higher alkylsubstituted hydantoin rings favored lower viscosities. Some anomalies in these viscosities presumably reflected either a tendency of certain resins to crystallize, or the presence of some species of higher molecular weight, formed by reaction of the glycidyl group with a second hydantoin ring.

Hydantoin-Based Epoxy Resins. These resins were commercialized by Ciba-Geigy. Hydantoins are prepared from carbon dioxide, ammonia, hydrogen cyanide, and ketones via the Bucherer reaction and can be epoxidized with epichlorohydrin (67). Cured and imcured resin properties depend greatly on the nature of the substituents R and R. The hydantoin derived from acetone furnishes a low viscosity, water-dispersable epoxy resin, 5,5-dimethyl-l,3-bis(2,3-epoxypropyl)-2,4-imidazolidinedione (R = R = CH3 145 EEM rj at 25°C 2.5 Pa s). A nonsintering solid epoxy resin is obtained if R = R = —(CH2)5—. 

Of the epoxy resin polymers, systems based on hydantoine segments with fragments such as... 

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