Epoxy hardener-resin combinations

The following coating resins were used (1) a vinyl ester (Dera-kane 470 from Dow Chemical) (2) a polyester (Atlac 382-05 AC from ICI) and (3) four epoxy resin/hardener combinations. The details of the resins and hardeners used are shown in Table I. One of the epoxy/hardener combinations was represented by materials from two sources. 

Although epoxy novolac resins are used in the present work, there is a fundamental difference from conventional encapsulant resins in that onium compounds in combination with copper acetyl(acetonate) are used in our materials as catalyst systems (2). These catalyst systems promote epoxy/epoxy polymerization and eliminate the need for hardeners. 

Theoretically, a cross-linked thermoset polsrmer structin-e is obtained when equimolar quantities of resin and hardener are combined. However, in practical applications, epoxy formulations are optimized for performance rather than to complete stoichiometric cimes. This is especially true when curing of high MW epoxy resins through the hydroxyl groups. 

Evans et al. [43] carried out 4 MeV electron irradiations of 14 different epoxy resins at 77 K which were selected from a large number of resin systems after screening tests on thermal shock at cryogenic temperatures [44]. The results of flexural tests show that most of these irradiated resins possess only moderate resistance to radiation. Takamura and Kato [45] tried to irradiate the bisphenol-A type epoxy resins with various hardeners at 5 K in a fission reactor and reported that the compressive strength of these epoxy resins decreased sharply after a combined neutron and y-ray irradiation equivalent to a dose of about 107 Gy. 

Epoxy resins are not finished products but are reactive chemicals which are combined with other chemicals to give systems capable of conversion to predetermined thermoset products. Manufacturers of epoxy resins and hardeners do not supply finished compounds. Some specialised firms perform the task of compounding for several products. 

A great many of outstanding adhesive formulations are based on epoxy resins. A broad spectrum of adhesive formulations with a wide range of available properties have resulted from the use of polymeric hardeners such as polyamides and polyamines, phenolics, isocyanates, alkyds, and combinations of amines with polysulfide elastomers, and the alloying of the epoxy with compatible polymeric film-formers, such as poly(vinyl acetate) and certain elastomers. 

Chem. Descrip. Aliphatic polyamine adduct (80%) in water Uses Hardener for solid epoxy resin disps. or emulsified liq. resins for use in water-reducible coatings on metallic substrates, corrosion-protection primers (in combination with Beckopox EH 386w)... 

Resin transfer moulding (RTM) is a low-pressure variation of transfer moulding where, instead of granules or preforms, a pre-mixed resin and catalyst (hardener) is injected into a closed mould containing dry glass, carbon or aramid fibre reinforcement. When the resin has cooled, the mould is opened and the composite part ejected. The resins used include polyester, vinylester, epoxies, phenolics and methyl methacrylate combined with pigments and fillers. Applications include small complex aircraft and automotive components as well as automotive body parts, baths and containers. 

The wide range of properties available from different combinations of epoxy resins and their hardeners can be further extended by the use of other additives. These include anti-oxidants, diluents, flexibilisers, stabilisers, tougheners, fillers, surfactants and adhesion promoters. 

Diluents. These are generally incorporated to reduce the viseosity of the freshly mixed adhesive to offset the effect of the filler. This may be required to improve handling and spreading characteristics or to allow filler additions which tend to reduce cost. Other properties of the fresh and hardened adhesive can be affected by the use of diluents, for example pot life, flexibility and glass transition temperature. If the diluent is non-reactive, such as solvents which remain in the cured system, the net result is a deterioration of chemical and mechanical properties such as increased shrinkage and reduced adhesion. Reactive diluents containing epoxy compounds are capable of combining chemically with the resin/hardener system. 

Epoxy or polyepoxide is a thermosetting polymer formed from reaction of an epoxide resin with polyamine hardener. Epoxy is used in coatings, adhesives and composite materials. They have excellent adhesion, chemical and heat resistance, good mechanical properties and electrical insulating properties. Epoxies with high thermal insulation, thermal conductivity combined with high electrical resistance are used for electronics applications. There are a few studies conducted on OPE-epoxy composites. 

Epoxy resins are widely used in coatings in applications requiring high resistance to abrasion and chemical resistance. Different types of resin and hardener combinations are used to tailor the properties to specific end uses. The increasingly more stringent requirements in many applications makes the enhancement of properties by the production of bicontinuous nanocomposites described previously a viable route for further developments in epoxy resin coatings. 

One-component Epoxy/PUR hybrid adhesive Combination and mixture of polyurethane and epoxy resin, where the epoxy group reacts with the latent hardener at high temperature... 

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