Epoxy adhesives Cresol Novolac resins

Epoxy cresol novolac epoxy resin, food-contact coatings Epoxy cresol novolac epoxy resin, high performance aircraft bodies/components p,p, p"-Tri (2,3-epoxypropoxy) triphenylmethane epoxy resin, high-temp, adhesives Epoxy cresol novolac epoxy resin, laminating prods. 

The neat novolac resins are also the precursors in the manufacture of a range of (see Epoxide adhesives), such as epoxy phenol novolacs and epoxy cresol novolacs spoxy resins. 

The increased functionality yields cured adhesives with higher crosslink densities resulting in higher temperature performance and increased chemical resistance. The functionality of commercially available, phenol based epoxy novolac resins varies from 2.3 to 6.0. Epoxy novolac resins can also be produced from substituted phenols like creosol and po-lyhydioxy phenols such as resorcinol. In the United States, Dow Chemical and Ciba-Geigy supply both phenol and cresol based epoxy novolac resins. 

Figure 12.7 Chemical formulae of phenolic resins used to prepare epoxy-phenolic adhesives based on Gunel Kagaku phenol novolac 61, Dow Chemical OCN ortho-cresol novolac 62, Mitsui Toatsu para-xylene-modified phenol novolac 63, phenolic ortho-ortho-resol of para-cresol 64, and poly (para-hydroxystyrene) 65.

This class of compounds is one of the most important adhesive groups with applications ranging from consumer to aerospace markets. Epoxies are thermosets and are cross-linked during the cure cycle. The chemical stmcmre for a simple epoxy (ethylene oxide) in its unhardened state is shown in Figure 5.2. All epoxy compounds contain two or more of these groups. Epoxy resins form adducts with vinyl, acrylic, and polyester resins producing compounds such as phenol novolac, cresol novolac, bis-[4(2,3-epoxy propyoxy) phenyl] methane, and phenol hydrocarbon novalac [53]. 

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