Epoxide cycloaliphatic

J. V. Koleche, Photochemistry of Cycloaliphatic Epoxides and Epoyy Ncrylates, Vol. I., ASTM International, 1989. 

Components Tributyl phosphate (79%) cycloaliphatic epoxide (2.0%) additives, including a triaryl phophate (21.0%) Mixture of 2-ethylhexyl diphenyl blend p-t-butyl phenyl blend triphenyl phosphate di(7-9-ii)Phthalate blend di-2-ethylhexyl phenyl phosphate Nonylphenyl diphenyl phosphate (-41%) cumylphenyl diphenyl phosphate ( 23%) tri phenyl phosphate (-36%)"... 

For simplification, the same cycloaliphatic epoxide was used throughout this investigation. The resin was the 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, designated ERL-4221 (Figure 1). Hexa-... 

This substantial toughening effect of CTBN on the cycloaliphatic epoxide ERL-4221, coupled with significant increase of the strength of the resin without seriously lowering the heat distortion temperature, is quite unusual for thermosetting systems. 

The IR spectra of a cycloaliphatic epoxide-ENR-GMA system based coating (Figure 3.7a)... 

Figure 3.7a FTIR spectrum of cycloaliphatic epoxide-ENR-GMA hybrid system...

But the key disadvantage is the narrow range of raw materials available to the formulator, thus restricting the flexibility allowed by the system. A typical formulation may contain vinyl ether diluents, a cycloaliphatic epoxide as the film forming material and photoinitiator. 

With respect to the photoinitiator and cycloaliphatic epoxide, there are fewer than ten products on the market. The choice is higher for vinyl ether diluents. 

The total theoretical heat of polymerization assuming conversion of all the epoxide functions to polymer was calculated to be 85 J/g. This was calculated from heats of reaction for cycloaliphatic epoxide monomers of 94.5 KJ/mol. 

The effects of temperature on rate of cure of mixtures of a cycloaliphatic epoxide and a DGEBA resin are shown in Table X. 

Table IX. Correlation of Viscosity, Epoxy Value, and Cure Time of Epoxide Coating Showing Dependence of Rapid Cure on Cycloaliphatic Epoxide...

Relationship between amount of cycloaliphatic epoxide added and cure rate at various temperatures... 

Anon. "Cycloaliphatic Epoxide Systems" Union Carbide Corporation, 1978. 

The formulations described in this paper were prepared using a dispersion disk and degassed In vacuum. The basic formulation of the resin matrix consisted of 33 parts of cycloaliphatic diepoxid, 33 parts of cresolnovolac epoxide, 33 parts of cycloaliphatic epoxy diluent, 0.5 parts of silane and 0.5 parts of photolnltlator (resin A). In addition fused silica 150 parts (resin B), 186 parts (resin C), 233 parts (resin D) was added. In the toughened mixture (resin E) the cycloaliphatic epoxide of resin D was substituted by 41.7 parts of a dispersion of 20Z silicone elastomer In epoxy resin. In the flexlbilized modification (resin F) 33 parts of epoxldlsed soya bean oil were added to resin D. 

Since coatings containing cycloaliphatic epoxides tend to be brittle, other compounds such as oligomeric polyols are frequently added as flexibilizing agents. Alcohols can react with the oxonium ions formed by the addition of protons to epoxide groups (see Scheme 11.2) and are thereby copolymerized with the epoxides. 

The compositions of materials photocrosslinkable by cationic mechanism consist of mixtures of various vinyl ethers, or epoxides, or both. Difunctional cycloaliphatic epoxides have been used extensively in some UV curable systems, often as diluents for the various epoxy resins described in Chapter 6. Use of various divinyl ethers is also extensive. Because some cationic photoinitiators also generate free radicals, some compositions may contain mixtures of both types of materials, those that cure by cationic and those that cure by free-radical mechanisms. 

Soucek, M.D. Abu-Shanab, O.L. Anderson, C.D. Wu, S. (1998). Kinetic Modeling of the Crosslinking Reaction of Cycloaliphatic Epoxides with Carboxyl Functionalized Acrylic Resins Hammett Treatment of Cycloaliphatic Epoxides. Macromolecular Chemistry and Physics, Vol.199, No.6, (December 1998), pp. 1035-1042, ISSN 1022-1352. 

Also, a European patent was applied for that describes cationic photoinitiators based on 2,4,6-triarylpyrylium salts with nonnucleophilic anions and electron donors. It is claimed that the photoinitiators rapidly photo crosslink mixtures of cycloaliphatic epoxides. Micro encapsulation of the salts in polystyrene was found to increase thermal and photo stability of these photoinitiators.The encapsulation material can be dissolved in monomers when polymerization is desired. 

The viscosity of the epoxide prepolymers in many instances is reduced by additions of thin liquid epoxy compounds fliat may include cycloaliphatic epoxides or lactones. Various epoxidized vegetable oils, like epoxidized linseed, sunflower, soybean, and others are also used in some formulations. Table 3.4. lists come cycloaliphatic epoxy monomers used for such purposes. Vinyl ethers polymerize at a faster rate than do cycloaliphatic epoxides. They are, therefore, included in some formulations. Other materials fliat are included for such purposes or to control viscosity can be epoxy novolacs, glycidyl ethers of long chain alcohols. To control viscosity, polyols might also be used, because it is assumed that hydroxy group bearing compounds crosslink with the epoxy resins. 

The authors claim that these materials exhibit higher rates of cure and higher enthalpies of photopolymerization than do the corresponding cycloaliphatic epoxides. 

A liquid radiation curable resin capable of curing into a solid upon irradiation has been described that contains a cycloaliphatic epoxide with a linking ester group, oxetanes, polyols, methacrylate components, impact modifiers and photoinitiators (33). 

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