A process for the preparation of an adhesive film for the adhesive bonding of metal sheets, or - films

摘要

Adhesive films for bonding metal sheets together, or for bonding metal sheets to other sheet materials, esp. wood sheets, are made by impregnating a carrier sheet with a compsn. comprising (a) an aq. dispersion of a copolymer of 60-95 wt. % vinyl acetate, 1-10 wt. % N-methylolacrylamide and 4-30 wt. % (meth)acrylic esters of 1-8C aliphatic alcohols, and (b) a phenol formaldehyde precondensate, and drying the impregnated sheet to form an adhesive film. Adhesive films give high peel strengths and are easier to apply than liquid adhesive compsns. Carrier sheet is pref. a paper sheet with a substance of 15-50 g./m.2 The phenolic resin is pref. a 1 : 1.2-2.5 phenol : formaldehyde resin of known type using 0.005-0.2 mol. basic catalyst (alkali- or alkaline earth hydroxide etc.) per mol. phenol and with a solids content of 50-90 wt. % and a viscosity of 60-1000 cP at 20 degrees C. The wt. ratio phenolic resin to vinyl acetate copolymer is pref.