A process of producing a polyimide block copolymer

摘要

A polyamide-type copolymer, a process of producing the same and use of the same in a thin layer forming agent. In order to provide a polyamide-type copolymer suitable for producing an alignment layer in an SBE type display element with high transparency, adhesion, pretilt angle etc, the present invention provides processes of producing a block copolymer type polyamic acid, a polyimide block copolymer, a polyimide-polyamic acid block copolymer and a liquid crystal alignment layer wherein, in separate steps, first and second prepolymers comprising polyamic acid prepolymers or polyamide prepolymers are prepared and subsequently reacted together, and if necessary, imidised. The invention also provides a thin layer forming agent having a first polyimide-type block and a second polyimide-type block bonded to the first polyimide-type block and having a different structure from the first polyimide type block.