PROCESS FOR PRODUCTION OF BROAD-BAND CHOLESTERIC LIQUID CRYSTAL FILM

摘要

Disclosed is a process for producing a broad-band cholesteric liquid crystal film having a reflection bandwidth of 300 nm or more, which comprises simplified steps and enables the production of a broad band cholesteric liquid crystal film that does not undergo discoloration and has good appearance. Specifically disclosed is a process for producing a broad-band cholesteric liquid crystal film having a reflection bandwidth of 300 nm or more, which comprises the steps of applying a liquid crystal composition comprising a polymerizable mesogen compound (a), a polymerizable chiral agent (b) and a thermal polymerization initiator (c) onto an alignment substrate and a step of increasing the bandwidth of the liquid crystal composition through thermal polymerization, wherein (i) the content of the thermal polymerization initiator (c) in the liquid crystal composition is 0.2 to 4 parts by weight relative to the total content (100 parts by weight) of the polymerizable mesogen compound (a) and the polymerizable chiral agent (b), and (ii) the thermal polymerization is carried out at a heating temperature of 70 to 150°C in an oxygen-containing inert gas atmosphere having an oxygen concentration of 5 vol% or less.