GB1370929A - Adhesive compositions - Google Patents

Abstract

1370929 Forms of wood MITSUBISHI PETROCHEMICAL CO Ltd and OOSHIKA SHINKOKK 1 Dec 1971 [2 Dec 1970] 55866/71 Heading B5L [Also in Division C3] Plywood is made by interposing between wood sheets layers of an adhesive composition comprising (1) an α-olefin homopolymer, a copolymer of two or more α-olefins or a copolymer of an α-olefin with an ethylenically unsaturated carboxylic ester and (2) 0À1 to 30 weight per cent of an isocyanate, and applying heat and pressure to bond the sheets. The adhesive may be applied as an extruded film, either while still molten or after cooling, or it may be applied as a melt, e.g. by roll coating, or as a powder. The polymer may be derived from ethylene, propylene, butene or hexene, and optionally an acrylic or methacrylic ester or vinyl acetate. The isocyanate may be o-chlorophenyl, α-naphthyl or phenyl isocyanate; methylene bis(4- phenylisocyanate), tolylene diisocyanate, hexamethylene diisocyanate or methyl 2,6-diisocyanatocaproate; or a tolylene diisocyanate/trimethylol propane reaction product. The adhesives may also contain fillers, e.g. talc, clay, carbon black, titanium dioxide, zinc dust, calcium carbonate and calcium sulphate; and tackifiers, e.g. alkylphenols, maleic modified rosin and rosin modified phenolic resins. Examples describe the preparation of plywood having a core and outer facing sheets of lauan wood using adhesives comprising polyethylene, polypropylene, or ethylene/propylene, ethylene/ethyl acrylate, ethylene/methyl acrylate, ethylene/acrylic acid/t-butylacrylate, ethylene/ glycidyl methacrylate/vinyl acetate, ethylene/ vinyl acetate or ethylene/vinyl acetate/methacrylic acid copolymers; isocyanates; and optionally calcium carbonate, magnesium silicate, aluminium silicate, silica or barium sulphate. The adhesive films may be bonded to the core by nip rolls and the facing sheets bonded thereto by hot pressing, or the core may be enclosed in a cylindrical film which may be heat shrunk to the core.