A method of preparing a colorless transparent copolyamide-imide resin solution and its fabrication as a thin film has been disclosed. The method details formulations derived from a reaction between one or more units of dianhydride and one or more units of diamine monomers with one or more of the monomers containing fluorine atoms in their structural unit. It enables the fabrication of thin films with superior thermal and mechanical properties along with co-efficient of thermal expansion values as low as 2 ppm/° C. and a tensile modulus as high as 9 GPa. The transparent copolyamide-imide film thus prepared has the potential for utilization in flexible displays such as substrates for thin film transistors (TFT), touch sensor panels (TSP) and cover window in organic light emitting diode (OLED) and liquid crystal display (LCD) applications.

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.

A method of manufacture of a polyetherimide composition includes contacting a substituted phthalic anhydride and an organic diamine in the presence of diphenyl sulfone, sulfolane, or a combination comprising at least one of the foregoing solvents at a temperature of greater than 130° C. to provide a bis(phthalimide) composition comprising diphenyl sulfone, sulfolane, or a combination comprising at least one of the foregoing solvents and a bis(phthalimide); and polymerizing the bis(phthalimide) and an alkali metal salt of a dihydroxy aromatic compound in the presence of diphenyl sulfone, sulfolane, or a combination comprising at least one of the foregoing to form a polyetherimide. The method does not require any catalyst either for the imidization or the polymerization.

The present invention provides curable, high molecular weight (>20,000 Daltons) polyimide compounds. The polyimides, once cured, possess a wide range of glass transition temperatures, have high tensile strength and high elongation. Furthermore, the cured polyimides are hydrophobic, have high glass transition temperatures, low coefficient of thermal expansion, very low dielectric constant and very low dielectric dissipation factor.

Provided is a polyimide resin composition and a production method thereof, wherein the polyimide resin composition contains an alicyclic polyimide resin having a structural unit represented by the following general formula (1) and inorganic particles of at least one selected from the group consisting of titanium dioxide, barium titanate, and zirconium oxide, wherein the alicyclic polyimide resin has a glass transition temperature of 260 C. or higher, ##STR00001## wherein R.sub.1 represents a tetravalent alicyclic hydrocarbon group having a carbon number of from 4 to 22, and R.sub.2 represents a divalent aliphatic hydrocarbon group having a carbon number of from 2 to 28 and/or a divalent aromatic hydrocarbon group having a carbon number of from 6 to 27.

A polyimide film contains fluorinated substituents and cardo structures. The polyimide film exhibits excellent heat-resistance, transparency and mechanical properties. The polyimide film has a glass-transition temperature (Tg) of at least 360 C., a coefficient of thermal expansion (CTE) of 50 ppm/ C. or lower, a modulus of at least 4.0 Gpa, a b* value of 5 or lower and yellowness index of 8 or less. The polyimide film can be used as a display substrate or an optical film in a liquid crystal display (LCD), an organic light-emitting diode (OLED) and in other fields where the characteristic features are required.

Provided is a resin composition capable of being turned into a cured product exhibiting excellent dielectric properties even at high frequencies and small changes in dielectric properties even after being left under a high temperature for a long period. The resin composition is a curable resin composition containing: (A) a maleimide compound represented by the following general formula (1)

##STR00001## wherein D independently represents a dimer acid- and trimer acid-derived hydrocarbon group; B independently represents a cyclic structure-containing divalent hydrocarbon group other than a dimer acid- and trimer acid-derived hydrocarbon group; A independently represents a tetravalent organic group having a cyclic structure; m is 0 to 100, n is 0 to 100; and (B) a catalyst, wherein D in the formula (1) is a group in which dimer acid-derived hydrocarbon group occupies 95% by mass or more of the dimer acid- and trimer acid-derived hydrocarbon group, and is a hydrogenated group.

The present invention relates to a liquid crystal alignment agent composition comprising a polymerizable liquid crystal alignment polymer; and a catalyst precursor compound of a specific structure, a method for preparing a liquid crystal alignment film using the same, and a liquid crystal alignment film and a liquid crystal display using the same.

The present invention provides a method of manufacturing a polyimide film including unit polymers that are omnidirectionally distributed, and a polyimide film. The present invention also provides a graphite sheet having good quality manufactured using the polyimide film.

The instant disclosure relates to a method for manufacturing a transparent polyimide film, including providing a polyamic acid solution having a fluorine content more than 12%; adding a dehydrating agent and a catalyst into the polyamic acid solution, the dehydrating agent having an equivalent number equal to or larger than 3; and baking the polyamic acid solution under a temperature ranging from 250 to 350 C. for performing a chemical imidization process so that the transparent polyimide film is obtained. The transparent polyimide film has an elongation rate of more than 30% and a b* value in a CIELAB coordinate of less than 3.5.