Patent ID: 8730437

Claim:
A method for making a treated polymer for a liquid crystal alignment agent, comprising the steps of: subjecting a tetracarboxylic dianhydride compound and a diamine compound to conduct a polymerization reaction to obtain an untreated polymer; preparing a co-precipitating solvent for the untreated polymer which includes a poor solvent in an amount of 800 to 900 parts by weight based on 1,000 parts by weight of the co-precipitating solvent and a good solvent, wherein the poor solvent is selected from the group consisting of a ketone, an ether, and a combination thereof; and subjecting the untreated polymer to a treatment with the co-precipitating solvent such that a polymer fraction having a molecular weight not larger than 3,000 is substantially removed from the untreated polymer to obtain the treated polymer.