Hot melt adhesives for seams of metal cans - comprising terephthalic acid-dimeric acid component, ethylene glycol copolyester and polystyrene

摘要

Adhesives (of melt viscosity 50-600P) comprise (a) 90-70 wt. % of copolyester having an inherent viscosity of >=0.35 (pref. 0.45-0.55) and (b) 30-10 wt. % of a vinyl polymer of inherent viscosity 0.1-0.8 (pref. 0.5-0.7) contg. >=50 wt. % polystyrene units. (a) is derived from a glycol component (I) and an acid component (II) where (I) is 80 mol % wrhyleneglycol and (III) is 60 mol. % terephthalic acid and 15-25 mol % dimer acid. Adhesives are useful for side and end seams of metal cans, partic, those subjected to sterilisation, e.g condensed mil or beer cans. They have improved extensibility and better adhesion at sterilising temp. than similar adhesives (US Pat. 3795644).