A liquid crystal aligning agent composition for forming a liquid crystal alignment film having improved electrical characteristics and high reliability while exhibiting excellent alignment properties and durability, a method for preparing a liquid crystal alignment film using the same, and a liquid crystal alignment film and a liquid crystal display device using the liquid crystal alignment film.

The present invention relates to a hydrophilic polyimide including at least one type of building blocks [A-B] and [A-C], and represented by the formula -[A-B].sub.n-[A-C].sub.m— (I), wherein: the n-bracketed building blocks and the m-bracketed building blocks are randomly distributed over the polyimide chain; repeat unit A results from a monomer comprising two carboxylic anhydride moieties, repeat unit B is hydrophilic and results from a first hydrophilic monomer comprising two primary amine moieties and at least one further hydrophilic moiety different from the primary amines, and repeat unit C is hydrophilic and results from a second hydrophilic monomer comprising two primary amine moieties and at least one further hydrophilic moiety different from the primary amines; wherein: n and m represent independently an integer from 0 to about 1000; wherein n+m is an integer from about 10 to about 1000.

The present invention also relates to a porous membrane comprising the same, a method of producing the hydrophilic polyimide and the porous membrane, a liquid phase separation system comprising the porous membrane, and a liquid phase separation method.

The present invention relates to a polymer having excellent liquid crystal alignment and electrical properties and thus is suitable for use as a liquid crystal alignment agent, a liquid crystal alignment agent containing the same, a liquid crystal aligning film formed from the liquid crystal alignment agent, and a liquid crystal display device containing the liquid crystal aligning film.

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 polyimide precursor solution is disclosed, and a colorless transparent polyimide film manufactured from the polyimide precursor solution. The polyimide precursor solution has diamines, a first dianhydride represented by biphenyl dianhydride, a second dianhydride represented by rigid alicyclic dianhydride, a third dianhydride represented by non-alicyclic dianhydrides and organic solvent. The colorless polyimide films have a modulus of 4.5 GPa or higher, a glass-transition temperature (T.sub.g) of 370° C. or higher, and a yellow index of 3.0 or lower. These polyimide films can be used as substrates for thin film transistor (TFT), touch sensor panel (TSP), and cover window applications in flexible display such as organic light-emitting diode (OLED), flexible liquid crystal display (LCD) and other fields.

A liquid crystal aligning agent composition for forming a liquid crystal alignment film that can exhibit excellent alignment and electrical characteristics and simultaneously having enhanced durability, a method for preparing a liquid crystal alignment film using the liquid crystal aligning agent composition, and a liquid crystal alignment film comprising an aligned and cured product of the liquid crystal aligning agent composition and a liquid crystal display device comprising the liquid crystal alignment film.

A manufacturing method of a continuous transparent polyimide film for a display includes the following steps providing a roll-to-roll polyimide film; providing a polyimide precursor, which is coated on the polyimide film; and baking the polyimide precursor at a baking temperature that is at least 20° C. higher than a glass transition temperature of the transparent polyimide film, such that the transparent polyimide film has an optical transmittance of greater than 85%, a chromaticity (b*) of less than 2, and a standard deviation of three axial refractive indices of the transparent polyimide film is less than 0.0012. Thus, the transparent polyimide film with reduced light leakage can be obtained.

The present invention relates to a cross-linking agent compound of which end functional group is substituted with a protection group of a specific structure, a liquid crystal alignment composition comprising the cross-linking agent compound and polymer containing repeat units of polyimide or a precursor thereof, a method of preparing liquid crystal alignment film, a liquid crystal alignment film, and a liquid crystal display using the same.

Provided are a polyimide-based film, a window cover film, and a display device including the same. More specifically, a polyimide-based film having different surface energies from each other on both surfaces, a window cover film having excellent optical properties such as a visibility, and a display panel including the same are provided.

The present invention relates to a liquid crystal aligning agent composition for forming a liquid crystal alignment film exhibiting excellent alignment and electrical characteristics and simultaneously having excellent film strength, a method for preparing a liquid crystal alignment film using the same, and a liquid crystal alignment film and a liquid crystal display device using the same.