Abstract
Cyclic monoterpene bisphenols as starting materials include a commercial terpene bisphenol (YP-90TM, Yasuhara Chemical Corp., a mixture of 1, 3-menthane bisphenol and 2, 8-menthane bisphenol (60 : 40 wt ratio)), 1, 3-menthane bisphenol, 2, 8-menthane bisphenol and terpene bis-2', 6'-dimethylphenol. Four kinds of novel epoxy resins were prepared in two step reactions, because the cyclic monoterpene bisphenols were hardly soluble in aq.NaOH solution : the reaction of the bisphenols and epichlorohydrin using a phase transfer catalyst, tetrabutylammonium bromide, at 80°C in the absence of alkali, followed by epoxidation with aq.NaOH solution at a lower temperature (<10°C). The differential thermal analysis indicates that the curing reactivities of the epoxy resins based on the cyclic monoterpene bisphenols (DGETB) were lower than that of bisphenol A diglycidyl ether (DGEBA) when using 3, 3'- dimethyl-5, 5'-diethyl-4, 4'-diaminodiphenylmethane (Curehard MEDTM, Ihara Chemical Corp.) as a curing agent. Physical properties for the Curehard MED-cured DGETB resins were examined. Tg's of the cured DGETB resins were higher than that of the cured DGEBA resin. Water absorption of the cured DGETB resin based on YP-90 was lower than that of the cured DGEBA resin. Physical properties for the DGETB resins cured with methyl hexahydrophthalic anhydride (MeHHPA) were also examined. In the MeHHPA curing system, Tg's for the cured DGETB resins were also higher than that for the cured DGEBA resin.
