Provided are a polyimide-based film, a window cover film, and a display panel including the same. More specifically, provided are a polyimide-based film having high tear strength and excellent optical properties, a window cover film, and a display panel including the same.

The present invention relates to a polyimide-based film which does not substantially cause a mura or rainbow phenomenon and has excellent visibility, a window cover film including the same, and a display panel including the same.

Provided are a polyamideimide film, a window cover film, and a display panel including the same. More specifically, a polyamideimide film including an amideimide structure derived from a dianhydride, a diamine, and an aromatic diacid dichloride is provided, wherein a chlorine content in the film is 5 to 33 ppm and a yellow index change amount ΔYI is 5 or less, the yellow index change amount being measured in accordance with ASTM E313 after repeating a process of irradiating 0.55 W/m.sup.2 of UVA at 340 nm at 40° C. for 20 hours and then blocking UVA for 4 hours three times.

A polymer film comprising at least two properties selected from (i) a thickness of not greater than 100 μm; (ii) a tensile modulus according to ASTM D882 of at least 5 GPa; (iii) a first optical transparency according to ASTM D1746-15 at 380 nm of less than 50%; (iii) a Yellowing Index according to ASTM E313-15e1 of not greater than 2.5; (iv) a haze as determined according to ASTM D1003-13 of not greater than 1.5%; (v) a pencil hardness of greater than 1H; (vi) a coefficient of moisture expansion (‘CME’) as determined according to ASTM D5229/D5229M-14 of not greater than 50 ppm; (vii) an elongation at break as determined according to ASTM D5034-09 (2017) of at least 10%; or (viii) a folding endurance as determined according to ASTM D2176-16 at a radius of 1 mm of at least 10,000 folds.

The present invention relates to a liquid crystal aligning agent composition capable of securing a high imidization rate under relatively mild curing conditions, minimizing side reactions and thus having excellent stability, a method for producing a liquid crystal alignment film using the same, and a liquid crystal alignment film and a liquid crystal display device using the same.

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 including the same, a liquid crystal alignment film formed from the liquid crystal alignment agent, and a liquid crystal display device including the liquid crystal alignment film are provided.

The present invention relates to a polymer which is excellent in terms of liquid crystal alignment property, durability, and electrical characteristics, and thus is suitable for use in a liquid crystal aligning agent, a liquid crystal aligning agent composition including the same, a liquid crystal alignment film formed from the liquid crystal aligning agent composition, and a liquid crystal display device including the liquid crystal alignment film.

A method for producing a polyimide film includes: obtaining a polyamic acid solution having a viscosity of 5 to 150 cps by preparing a raw material mixture liquid containing a solvent, a tetracarboxylic dianhydride represented by a specific general formula, and an aromatic diamine represented by a specific general formula, and has a total content of the tetracarboxylic dianhydride and aromatic diamine of 15% by mass or less, and reacting the tetracarboxylic dianhydride and aromatic diamine with each other in the raw material mixture liquid forming a polyamic acid having a repeating unit represented by a specific general formula; obtaining a polyimide-forming mixture liquid by adding a compound represented by a specific general formula to the polyamic acid solution; and obtaining a polyimide film represented by a specific general formula by forming a film made of the polyimide-forming mixture liquid, followed by imidization of the polyamic acid in the film.

Provided is a hard coating film including a polyamideimide substrate layer and a hard coating layer, each of which has a predetermined refractive index, with a difference in the refractive index between those layers being 0.05. The substrate layer has a tensile modulus of 3 to 7 GPa, at a thickness of 80 μm, as measured according to ASTM D111. The present invention relates to a hard coating film having improved mechanical and optical properties.

A class of solvent resistant, flexible copolyimide substrates having high optical transparency (>80% from 400 to 750 nm) that is retained after brief exposure to 300° C., near-zero birefringence (<0.001) and a maximum CTE of approximately 60 ppm/° C. is disclosed. The copolyimides are prepared from alicyclic dianhydrides, aromatic cardo diamines, and aromatic diamines containing free carboxyl groups. The substrates are manufactured from solutions of the copolyimides containing multifunctional epoxides in the form of single layer films, multilayer laminates and glass fiber reinforced composite films. The substrates can be used in the construction of flexible optical displays, and other microelectronic and photovoltaic devices that require their unique combination of properties.