Adhesives and coatings based on poly(vinyl acetal)s

摘要

Phenolic resins such as resole phenol- and cresol-formaldehyde, as well as low-molecular-weight epoxy resin based on bis(4-hydroxy phenol) cyclohexane were prepared and modified with various types of the prepared poly(vinyl acetal)s. Poly(vinyl formal), poly(vinyl isobutyral), and poly(vinyl propional) were used. This study indicated that the optimum conditions for curing phenolic or epoxy resin-poly(vinyl acetal)s adhesive compositions are of an equal weight ratio or a 2 : 1 weight ratio in the presence of phthalic anhydride (10 or 20 wt %) of resin content as a curing agent at 150 degrees C for 20 or 60 min, respectively. The effect of acetal type on the tensile shear strength values of resin samples, cured under the previously mentioned optimum conditions for different times, was investigated. The effect of structure of cresol-formaldehyde and epoxy resins was also studied. Metallic and glass coatings from the previous pure resins and their formulated mixtures were also prepared and evaluated as varnishes or paints. (C) 1998 John Wiley & Sons, Inc. [References: 25]