A liquid crystal alignment agent and a preparation method thereof, a liquid crystal alignment film and a preparation method thereof, and a liquid crystal cell are provided. A piperazine monomer is added to a liquid crystal alignment agent, a bulk resistance value and a surface resistance value of a liquid crystal alignment agent material can be reduced, and the ability of the liquid crystal alignment agent material to release residual charges can be effectively improved, thereby increasing the reliability and stability of an electronic product. The liquid crystal cell using the liquid crystal alignment agent has advantages such as high voltage holding ratio (VHR) and low residual voltage.

Provided are a polymer having a constituent component represented by formula (I) below, a method for producing the polymer, a diamine compound suitable as a raw material for the polymer, a gas separation membrane haying a gas separation layer including the polymer, and a gas separation module and a gas separation apparatus that have the gas separation membrane. ##STR00001## In the formula (I), R.sup.A, R.sup.B, and R.sup.C represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom. Herein, at least one of R.sup.A, R.sup.B, or R.sup.C represents an alkyl group having 1 to 4 carbon atoms or a halogen atom. The alkyl group having 1 to 4 carbon atoms is not trifluoromethyl and ** represents linking sites.

The present invention provides an optical film and a display device including same, the optical film comprising a polymer resin which includes: a first repeating unit; a second repeating unit; a third repeating unit; and a fourth repeating unit, wherein the first repeating unit is an imide repeating unit derived from a first diamine-based compound and a dianhydride-based compound, the second repeating unit is an imide repeating unit derived from a second diamine-based compound and a dianhydride-based compound, the third repeating unit is an amide repeating unit derived from a first diamine-based compound and a dicarbonyl-based compound, and the fourth repeating unit is an amide repeating unit derived from a second diamine-based compound and a dicarbonyl-based compound. The first diamine-based compound is 2,2′-Bis(trifluoromethyl)benzidine (TFDB), the second diamine-based compound includes aromatic diamine-based compounds, and the number of amide repeating units including the third repeating unit and the fourth repeating unit is at least 80% of the total number of repeating units including the first to fourth repeating units.

Disclosed is a manufacturing method of a liquid crystal display device which is a manufacturing method of a liquid crystal display device including a liquid crystal alignment film to which an alignment regulating force is imparted by a photo-alignment treatment, including: a film forming step of forming a film containing a polymer whose main chain is cleaved by irradiation with light; a photo-alignment step of imparting an alignment regulating force to the film formed in the film forming step by irradiation of the film with light in an atmosphere of a temperature lower than 100° C.; and a removing step of removing a low-molecular weight component generated by cleaving the main chain of the polymer through the light irradiation after the light irradiation. Also disclosed is a liquid crystal display device manufactured by the manufacturing method.

According to one embodiment, a varnish for a photo alignment film includes an imidization promotor and a first polyamic acid-based compound in an organic solvent. The first polyamic acid-based compound is a polyamic acid or a polyamic acid ester. The imidization promotor has skeleton containing no primary amino group and no secondary amino group. The first polyamic acid-based compound has terminal skeletons containing no primary amino group.

A method for controlling a polyimide backbone structure, including: in preparation of a polyimide through reaction of a diamine component and (1S,2R,4S,5R)-cyclohexanetetracarboxylic dianhydride in an organic solvent containing an aprotic amide solvent and a lactone solvent, adjusting one or more of reaction conditions of a mass ratio of the aprotic amide solvent and the lactone solvent, a reaction temperature, a reaction time, and an amount of the aprotic amide solvent, so as to convert a cis-structure derived from the (1S,2R,4S,5R)-cyclohexanetetracarboxylic dianhydride in the formed polyimide to a trans-structure derived from (1R,2S,4S,5R)-cyclohexanetetracarboxylic dianhydride corresponding to the reaction conditions, thereby controlling a proportion of the trans-structure.

A liquid crystal alignment agent composition for producing a liquid crystal alignment film having enhanced alignment property and stability and a high voltage holding ratio, a method of producing a liquid crystal alignment film using the same, and a liquid crystal alignment film and a liquid crystal display device using the same, are provided.

A resin composition contains a polyimide resin and an ester-based resin. The ester-based resin is polycarbonate or polyarylate. The polyimide contains a structural unit represented by general formula (1). In general formula (1), X is a divalent organic group shown in group (I), and Y is a divalent group that contains one or more selected from the group consisting of a fluorine group, a trifluoromethyl group, a sulfonic group, a fluorene structure and an alicyclic structure. Each of R.sup.1 and R.sup.2 is a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a fluoroalkyl group having 1 to 20 carbon atoms, m is an integer of 1 to 4, and n is an integer of 0 to 4.

##STR00001##

A method for producing an aqueous polyimide precursor solution composition includes forming a polyamic acid by the reaction of a tetracarboxylic acid component and a diamine component in an aqueous solvent together with an imidazole in an amount of 1.6 mole or more per mole of the tetracarboxylic acid component of the polyamic acid.

Disclosed is a manufacturing method of a liquid crystal display device which is a manufacturing method of a liquid crystal display device including a liquid crystal alignment film to which an alignment regulating force is imparted by a photo-alignment treatment, including: a film forming step of forming a film containing a polymer whose main chain is cleaved by irradiation with light; a photo-alignment step of imparting an alignment regulating force to the film formed in the film forming step by irradiation of the film with light in an atmosphere of a temperature lower than 100° C.; and a removing step of removing a low-molecular weight component generated by cleaving the main chain of the polymer through the light irradiation after the light irradiation. Also disclosed is a liquid crystal display device manufactured by the manufacturing method.