Polyvinyl formal-phenolic adhesive properties

Peel resistance. The straight epoxies cured by either polyamines (amides) or anhydride are poor in peel. Polyvinyl formal-phenol formaldehyde (P/F) and butyral-P/F are moderate but the peel varies with the P/F content. As the P/F content increases, room temperature lap-shear and peel strength decrease but these properties improve at elevated temperatures. The epoxy-polyamides (epoxy-nylon) such as FM1000 (Cyanamid Corp.) give extremely good peel resistance under dry conditions. Hockney (1970) quotes 511N for an adhesive of this type with a strip 25 4 mm wide, peeled at 90°. The peeling... 

In the waterborne phenolic adhesives, a new dispersion system (98) has been reported. This system uses the solubility of some thermoplastics in phenol, and the subsequent polymerization takes place upon the addition of formaldehyde, an emulsifier, and water. The dispersion is then formed in situ. The versatility of this process is indicated by the use of many polymers with a wide range of properties, e.g., polyvinyl formal, polyvinyl butyral, acrylonitrile-butadiene copolymer, bisphenol-A resins, polyvinyl acetate, polycarbonate, polymethyl methacrylate, and nylons. 

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