The invention provides
polyester resin as well as a preparation method and application thereof. The
polyester resin is prepared from raw materials including
dicarboxylic acid,
diphenolic acid, dihydric
alcohol and a catalyst through a stepwise
polymerization method, the number-average molecular weight of the
polyester resin is 25000-40000, the
glass transition temperature is 10-30 DEG C, and the
hydroxyl value is 2-10 mgKOH / g; the
polyester resin is synthesized through a distributed feeding method,
diphenolic acid is reserved at the end of a polyester chain, the end of the resin contains a
benzene ring and a plurality of hydroxyl groups, after the resin reacts with a curing agent, a local hard segment can be formed, the local hard segment is relatively soft with a polyester main
long chain, the local hard segment and the polyester main
long chain interact, and the elasticity is greatly improved. Compared with common resin, the
diphenolic acid has a special structure, and can form a functional group with a structure similar to that of a PI film after curing, so that the
adhesive force of the resin on substrates such as the PI film is increased, and meanwhile, the balance of
solvent resistance and flexibility is considered.