Hot‐melt adhesive bonding of polyethylene with ethylene copolymers

The melt bon debility of ethyl en e copolymers to a high, pressure polyethylene has been investigated by a T‐peel test consisting of polyethylene–copolymer–polyethylene. The three ethylene copolymers involved separately vinyl acetate, ethyl acrylate, and acrylic acid. The ethyl acrylate copolymers produce the highest peel strength over the test temperature range of −20 to 50°C, and also yield a high peel strength even at the bonding temperatures of 105–110°C, at which the welding of polyethylene to polyethylene does not occur. The observations of cross sections of the joints with an interference microscope show the presence of an interfacial boundary layer and a mixed layer (of the polyethylene and the copolymer). The relationship between the peel strength and these two layers is discussed. Further, the peel strength‐temperature curves are compared with the tensile properties of the copolymers.