Epoxy-phenolic Resins

Novolac resins are broadly used in electronics because their functionality higher than two increases the crossimkmg density and yields cured resins exhibiting enhanced chemical and physical properties. Mixtures of epoxy resins and phenol novolacs 61 are excellent structural adhesives in the aerospace industry. However, the phenolic hydroxyl groups are not very reachve at moderate temperatures and most systems include catalysts or accelerators. Classical adhesive compositions are prepared by mixing a solid epoxy resin, t5rpicahy an epoxidized phenol novolac resin (60 parts), a phenol novolac resin (40 parts), a solvent such as 2-butoxyethanol or butylcehosolve acetate, an imidazole catalyst, and silver flakes. 

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Epoxides can react with alcohols via acidic or basic catalysed reaction mechanisms. However, since both strong acids and bases will degrade the cell wall polymers of wood, the reaction is usually catalysed via the use of amines, which are more strongly nucleophilic than the OH group. For example, whereas the production of epoxy-phenolic resins requires temperatures in the region of 180-205 °C, reaction between epoxides and primary or secondary amines takes place at 15 °C (Turner, 1967). Reaction of epoxides with wood often involves the use of tertiary amines as catalysts (Sherman etal., 1980). The sapwood is more reactive towards epoxides than heartwood (Ahmad and Harun, 1992). 

Uses. A high-production-volume chemical used in manufacture of epoxy-phenolic resins (protective linings for food and beverage cans) monomer for polycarbonate resins (used in food contact materials such as returnable beverage bottles, infant feeding bottles, plates, and mugs) antioxidant in PVC plastics inhibitor of end polymerization in PVC plastics... 

Glass transition temperatures were determined refractometrically, as described by Wiley (20), with an Abbe refractometer supplied by Bellingham and Stanley. This instrument can normally be used only at temperatures up to 70°C. The prisms of this instrument were coated with a heat resistant adhesive (epoxy-phenolic resin mixture). After this modification the refractometer can be used at temperatures up to 200°C. 

Julia D. Harp, Exec. VP/Pres., Coatings Inks Joseph P. Bevilaqua, Exec. VP/Pres., Epoxy Phenolic Resins Richard L. Monty, Exec. VP-Environmental Health Safety Craig O. Morrison, Chmn. 

Epoxy-phenolic resin outstanding overall resistance, including methanol requires heat for ultimate cure... 

Combining phenolic resins with epoxy resins results in films with good chemical resistance and flexibility. Interior coatings based on these resin combinations are applied with a solids content of 33 43 % and cured at 200 "C in 80 s. Epoxy-phenolic resin lacquers are used in high amounts for can coating. 

Three-piece (body and two lids) cans are now welded instead of soldered. The welding seam is coated separately with epoxy-phenolic resins or PVC organosols that are cured at 260 C for 10 20 s. The PVC organosols result in higher dry film thicknesses, whereas the epoxy phenolic welding seam coatings have better chemical resistance. 

Details A solid in flake, crystal or dust form. Used in production of epoxy-phenolic resins, monomer of polycarbonates (PC), an antioxidant for PVC, and as an inhibitor used during PVC polymerisation. PC are widely used in many consumer products, from sunglasses and CD to water and food containers and shatter-resistant baby bottles. Some polymers can also contain bisphenol A, and epoxy resins containing bisphenol A are common coatings used in food cans. 

Epoxy adhesives are generally limited to continuous applications below 300°F (149°C). However, there are epoxy formulations that can withstand short terms at 500°F (260°C) and long-term service at 300-350°F (149-177°C). A combination epoxy-phenolic resin has been developed that will provide an adhesive capability at 700°F (371°C) for short-term operation and continuous operation at 350°F (177°C). 

Chem. Descrip. Polyolefin wax disp. in solvent Uses Surf. modiTrer, lubricant, slip agent, scratch resist, aid for can coatings, coil coatings, general industrial coatings based on polyester, ep-ory ester melamines, epoxy phenolic resins Features High gloss retention Properties Disp. 

Synonyms Epoxy novolac resin Epoxy-phenolic resin Epoxy phenol novolac 2-Phenoxymethyloxirane, compd. with formaldehyde Poly [(phenyl glycidyl ether)-co-formaldehyde... 

Epoxy novolac resin Epoxy-phenolic resin Epoxy phenol novolac. See Epoxy-novolac... 

Thermoset—A plastic that is substantially infusible and insoluble after being cured by heat or other means, e.g. polyester, epoxy, phenolic resin. 

AF 131, based on epoxy-phenolic resins, provides Al/Al bonds with lap shear strengths of 25.5, 20 and 10.3 MPa at 180, 200 and 260°C, respectively. Solventless epoxy and epoxy-phenolic adhesives provide bond lines with a low level of porosity. This is also the case with poly(ether-imide) Ultem 1000 and poly(imide-siloxanes), which are generally processed at temperatures 50-100°C above their Tg. In contrast, high porosity is observed with most condensation... 

Heise, M. S., Martin, G. C., and Gotro, /. T., Characterization of imidazole-cured epoxy phenol resins,/. Appl. Polym. Sci., 42, 1557, 1991. 

Results of the tests indicate that, of the adhesives tested, the types most suitable for low-temperature use would employ epoxy-phenolic resins supported on glass cloth, or filled epoxides, if present bonding difficulties could be overcome. 

In summary, it would seem that the best low-temperature adhesive, among those tested here, would consist of epoxy or epoxy-phenolic resins supported on a glass cloth film and filled with metallic dust to a degree necessary to approach the thermal expansion of the adherend. 

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