Method for producing both-end hydroxyl group butadiene oligomer, method for producing flexographic printing plate, and method for producing liquid crystal alignment film

摘要

PROBLEM TO BE SOLVED: To provide a butadiene oligomer having hydroxyl groups at both ends, in which only a low molecular weight component is favorably removed at a high percentage without varying a molecular weight, and to provide a flexographic printing plate comprising the butadiene oligomer having hydroxyl groups at both ends, and a liquid crystal alignment layer formed by flexographic printing using the above flexographic printing plate.SOLUTION: The butadiene oligomer having hydroxyl groups at both ends is obtained by removing a low molecular weight component from a raw material oligomer through steps of stirring the raw material with a solvent without heating, leaving the material to stand so as to separate a supernatant, and decanting. The flexographic printing plate is manufactured by using the butadiene oligomer having hydroxyl groups at both ends as a start material. The liquid crystal alignment layer is formed by flexographic printing using the above flexographic printing plate.