Epoxy-vinyl plastisol

Many different adhesives have been tested and used in weldbonding. These include both high-strength structural adhesives, such as modified epoxies, and relatively low-strength adhesives, such as vinyl plastisols or epoxy-polysulfides that are commonly used for sealing and vibration damping. Table 14.10 shows that a variety of adhesives and substrates are compatible with the weldbonding process. 

Weldbonded aluminum joints (1-mm aluminum alloy 2036-T4) where compared with spot welded aluminum (1-mm aluminum alloy 2036-T4) and spot welded steel (1-mm steel 1010) joints.45,46 Weldbonded 2036-T4 joints made with a vinyl plastisol adhesive and with a one-part modified epoxy had a fatigue strength about twice that of the spot welded aluminum alloy and approximately the same as that of the spot welded steel. The fatigue strength of the weldbonded aluminum joints with polysufide-epoxy adhesive or with high-peel-strength epoxy adhesive is higher than that of steel spot welds alone. 

A novel, latent curing system, which gives more than one year pot life at room temperature, has increased the use of epoxies for specialty adhesives and sealants, and for vinyl plastisols. The one-pack system provides fast cure when heated—for example 5 min at 100°C. 

More recent efforts have focused on developments that create true hybrids. For example, blocked isocyanate prepolymers have been mixed with epoxy resins and cured with amines [68-70]. These blocked prepolymers will react initially with the amines to form amine-terminated prepolymers that cross-link the epoxy resin. Several blocked isocyanates are commercially available. The DESMOCAP (Bayer) llA and 12A products are isocyanates (believed to be blocked with nonylphenol) used as flexibilizing agents for epoxy resins. ANCAREZ (trademark. Pacific Anchor, Inc.) 2150 is a blocked isocyanate epoxy blend used as an adhesion promoter for vinyl plastisols. A one-package, heat-cured hybrid adhesive was reported consisting of isophorone diisocyanate, epoxy resin, and a dispersed solid curative based on the salt of ethylenediamine and bisphenol A [71]. Urethane amines are offered commercially that can be used with epoxy resins to develop hybrid adhesive systems [72]. 

Chem. Descrip. Aminopropyltriethoxysilane CAS 919-30-2 EINECS/ELINCS 213-048-4 Uses Adhesion promoter for solv., water-based, solventless, and powd. system coupling agent tor metal treatment resin additive in mineral-reinforced polyester resin improves chem. bonding of resins to inorg. surfaces pigment treatment effective as primer or additive, esp. in epoxy, phenolic, PU, vinyl plastisols and imide systems food pkg. adhe-siv6s... 

Adhesives recommended include modified epoxies, modified phenoUcs, epoxy-phenolics, neoprene-phenolics, second-generation acrylics, cyanoacrylates, silicone rubbers, and vinyl plastisols. Sell has ranked a number of adhesives in the order of decreasing durability with aluminum adherends as follows ... 

It should be mentioned that acceptable bonds have been obtained in the auto-manufacturing industry using untreated and oily steel surfaces employing hot-curing adhesives, like the vinyl plastisols or specially formulated one-part epoxies.( i i27)... 

Uses Plasticizer, flame retardant for plastics incl. acrylics, ceiiuiosics, epoxy, nitrile, phenolic, thermoset po ester, PP, PS, PVAc, PVC, clear vinyl films, vinyl-coated fabrics, flexible PU foam, syn. rubber, wire/ cable insulation, plastisols plasticizer, coalescing agent for coatings Manuf./Dlstrlb. Akzo Nobel FMC Rhodia/Phosphorus Perf. Derivs. Trade Names Antiblaze 519... 

Epoxy resins are also combined with phenolic resins and poly(vinyl acetate) resins and used as adhesion promoters, for example, in plastisol adhesives. 

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