Prodn. of polyimide endless band having no weld joins - by coating polyamide acid soln. on hollow glass cylinder having pre-determined inner dia. and length, heating, and removing band by hydrothermal treatment

摘要

Prodn. comprises coating a hollow glass cylinder having a pre determined inner dia. and length at least on the inner side with a polyamide acid soln. which is heated to convert it to polyimide. The polyimide is then detached from the cooled cylinder by hydrothermal treatment to obtain a polyimide endless band. ADVANTAGE - The endless band has no glued join as in prior art bands which is a source of weakness