Non‐catalytic anhydride curing of hydrogenated bisphenol‐A glycidyl ether with 1,2,4‐cyclohexanetricarboxylic anhydride and light emitting diode encapsulation

Noncatalytic anhydride curing of hydrogenated bisphenol‐A glycidyl ether (YX8000) using hydrogenated trimellic anhydride (1,2,4‐cyclohexanetricarboxylic anhydride, H‐TMAn) and methylhexahydrophthalic anhydride (MeHHPA) were studied. Differential scanning calorimetry data shows no exthothermal under 190°C using MeHHPA without catalyst because of the low reactivity. On the other hand, H‐TMAn had higher reactivity and it can be cured without catalyst. The effect of anhydride concentration both on curing and on properties was studied in detail. For example, the highest T_g was found when YX8000 : H‐TMAn = 100 : 75 or YX8000 : MeHHPA = 100 : 100. The highest curing exothermal was found at similar ratio. Following, the encapsulation of light emitting diode (LED) was prepared with two anhydrides. Surface volume decrease was observed with MeHHPA by its evaporation, but H‐TMAn gave flat surface. After thermal cycle test of these LED, H‐TMAn was found to have better crack resistance than MeHHPA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 962–966, 2006