This paper discusses a new high-molecular-weight thermoplastic polymer recently developed in the laboratories of the Union Carbide Plastics Co. Its repeating unit is the same as commercial solid epoxy coating resins, but differs in that it is much higher in molecular weight (30,000 versus 340 to 4000) and does not contain terminal epoxy functionality. It is thermally stable and can be fabricated by most techniques applicable to thermoplastics. The material is strong, tough, rigid, and exhibits good dimensional stability. It is completely amorphous with a major glass transistion temperature range in the area of 100 C.
Its relationship to epoxy resins is reflected in its adhesive nature. High bond strengths are obtained with numerous substrates—for example, 3300 psi tensile lap shear strength to aluminum. Such bonds are maintained to a large extent under a wide variety of environmental conditions with a maximum temperature range of 200 F.
Historically, one of the serious limitations of thermoplastic adhesives has been poor creep resistance. The performance of the subject material, however, surpasses that of commonly used thermosetting adhesives.