Cycloaliphatic epoxies

Cycloaliphatic Epoxy Resins. This family of aUphatic, low viscosity epoxy resins consists of two principal varieties, cycloolefins epoxidized with peracetic acid and diglycidyl esters of cycHc dicarboxyhc acids. 

Oligomers and Resins. Oligomers and resins used were Ebecryl 3700 epoxy acrylate, Radcure Specialties, Inc., Smyrna, GA 30080 Unicarb, which is 73% UVR 6128 (a cycloaliphatic epoxy), 26.5% polyol and 0.5% Silwet L-7602 (See under miscellaneous compounds), Union Carbide Chemicals and Plastics Co., Inc., Danbury, CT 06817-0001 and Heloxy 505 Modifier, Shell Chemical Co., Houston, TX 77210. 

Cycloaliphatic epoxy III DIBFg J. 0% 60 60 % pickoff 5 50 400g Overall wrinkling Moderate rusting Dense 6 blisters Bleaching... 

The DIBF OPPI combination has been shown to efficiently cure a wide variety of epoxies including cycloaliphatics. With this photoinitiator it is possible to cure bisphenol A epoxies such as Epon 828 quickly without the need for acrylation of the epoxy. Cycloaliphatic epoxies were of special interest because they were expected to react much faster than bisphenol A type epoxies. Those tested include 3,4-epoxycyclohexylmethyl-3 ,4 -epoxycyclohexyl-carboxylate (UVR 6110), bis(3,4 epoxy-cyclohexylmethyl) adipate (UVR 6128), and 1,2-epoxy-4-vinylcyclohexane (vinyl cyclohexene oxide). It was found that the vinyl cyclohexene oxide reacted rapidly, but work with it was discontinued because it has a fairly high vapor pressure (2 torr at 20 °C), an intense odor, and the photoinitiator does not dissolve in this resin. 

A promising formulation was produced which contains the cycloaliphatic epoxy UVR 6110. The formulation contains 73% of the epoxy, 26.5% Polyol, 5% Silwet L7602 0.1% DIBF, 2.5% OPPI and 5-10 drops FC-171 in 100 g of... 

Epoxy ester-alkanol amine adduct Reaction product of ester-linked cycloaliphatic epoxy with diethanol amine. 

Batog, A.E., Pefko, I.P. and Penczek, R Aliphatic-Cycloaliphatic Epoxy Compoimds and Polymers. Vol. 144, pp. 49-114. 

Source Cyracure Cycloaliphatic Epoxies, Cationic UV Cure, Form 321-00013-0901 AMS, Dow Chemical Company (2001). 

Reinforcement of Thermosetting Cycloaliphatic Epoxy Systems with Elastomers... 

Tpo maximize the utility of crosslinked cycloaliphatic epoxy resins in some of the more critical application areas, improved toughness is required. Such improvements can often be made through modification with various flexibilizing agents, but as a rule this improvement is accompanied by a severe degradation of the strength and heat distortion temperature of the cured system. 

The reactivity of cycloaliphatic epoxy monomers with cations is higher than that of glycidyl ether monomers. For this reason, cycloaliphatic epoxies are used for UV-cure coatings. The most efficient initiators are complex aromatic salts of Lewis acids such as diaryl iodonium, triarylsul-fonium, or arene diazonium (Table 2.23) (Crivello, 1999). 

Figure 6 Emission spectra of /ac-ClRe(CO)3(4,7-Ph2-phen) in the cycloaliphatic epoxy (ERL-4221)/anhydride resin at 293 K (a) before curing, (b) partially cured by heating at 393 K for 30 min, and (c) cured by heating at 393 K for 60 min. Excitation wavelength is 400 nm. Intensities of spectra (a) and (b) have been scaled xlO and x5, respectively. (From Ref. 80.)...

Table 4 Electronic Absorption and Emission Maxima of the MLCT Bands Observed from/ac-XRe(CO)3L Complexes in Deoxygenated Methylene Chloride and the Cycloaliphatic Epoxy (ERL-4221)/Anhydride System at 293 Ka...

Figure 9 illustrates the dynamic moduli and complex viscosity results for the cycloaliphatic epoxy/anhydride resin. The tgei value denotes the time to gelation based on the dynamic moduli crossover (G = G") and is estimated at... 

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