Hot-melt adhesive of a copolyester of a dibasic acid with a polyhydric

Abstract

Disclosed is a hot-melt adhesive which comprises a copolyester of a dibasic acid component comprising 70 to 97 mole % of terephthalic acid and other dibasic acid with a polyhydric alcohol component comprising 70 to 97 mole % of 1,4-butane-diol, 3 to 30 mole % of diethylene glycol and up to 20 mole % of other polyhydric alcohol having 2 to 5 carbon atoms, said copolyester having a reduced viscosity of at least 0.6 dl/g as measured at a temperature of 30.degree. C. in a phenol/tetrachloroethane mixed solvent having a phenol/tetrachloroethane weight ratio of 60/40 at a polymer concentration of 0.25 g/100 ml, a glass transition temperature of at least 31.degree. C. and a crystallinity of 15 to 40 %. This hot-melt adhesive is excellent in the operation adaptability, and in the form of a film, the adhesive has an appropriate rigidity and a good dimension stability. Furthermore, when this hot-melt adhesive is formed into an adhesive layer between seams by hot bonding, the adhesive layer provides a high creep resistance and a good dimension stability. This hot-melt adhesive is valuably used for producing a metal vessel having a circumferential side seam by bonding cup-shaped lower and upper members along circumferential open ends of the two members.