A transparent polyimide film, prepared from a copolymerized polyamide acid according to a chemical cyclization method, is provided. The copolymerized polyamide acid requires at least a semi-aromatic polyamide acid, and the semi-aromatic polyamide acid is formed by reacting cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA) and 2,2′-bis(trifluoromethyl)diaminodiphenyl (TFMB). The molar number of dianhydrides of the semi-aromatic polyamide acid is more than 20% of the total molar number of anhydrides of the copolymerized polyamide acid, so that the transparent polyimide film has a light transmittance greater than 80%, a chroma b* less than 5, and a CTE less than 35 ppm/° C.

A tetracarboxylic dianhydride represented by the following general formula (1): ##STR00001##
[in the formula (1), R.sup.1, R.sup.2, and R.sup.3 each independently represent a hydrogen atom and the like, and n represents an integer of 0 to 12], wherein a ratio of a summed amount of a specific stereoisomer (A) and a specific stereoisomer (B) is 50% by mole or more relative to a total amount of stereoisomers based on three-dimensional configurations of two norbornane rings in the general formula (1), and a content ratio of the stereoisomer (A) is 30% by mole or more relative to the total amount of the stereoisomers.

A crosslinked polyimide, a polyimide film and a method for preparing thereof, an organic light emitting diode (OLED) device. 4,40-diamino-400-N-carbazolyltriphenylamine and 1,2,4,5-cyclohexanetetracarboxylic dianhydride and a p-xylylenediamine crosslinker are introduced in the present invention. The introduction of a diamine monomer with a large volume of pendant groups increases an asymmetry of the polyimide, destroys a close structure of the polymer, and reduces crystallization properties of the polypolymer, thereby effectively increasing its transmissibility. At the same time, a cross-linked agent, p-xylylenediamine, is introduced, and the cross-linked agent widens a molecular chain spacing, so that the polyimide molecule has a larger free volume. At the same time, the formation of cross-linked is beneficial to reduce a polarizability of the molecule, thereby reducing a dielectric constant of the material. An OLED device with a novel low dielectric constant and high transmittance is prepared in this way.

A polyimide copolymer, a polyimide film, and a manufacturing method of the polyimide film are provided. The polyimide copolymer includes a plurality of repeating units represented by a following formula (I) and a plurality of repeating units represented by a following formula (II).

##STR00001##

A structural formula of a substituent R.sub.1 is shown as follows:

##STR00002##

A structural formula of a substituent R.sub.2 is shown as follows:

##STR00003##

In addition, the polyimide copolymer has a weight average molecular weight (Mw) of between 30,000 and 200,000.

Provided are a hydrophilic polyamide and polyimide retaining characteristics particular to polyamides and polyimides, such as heat resistance. A polymeric compound is provided having a repeating unit represented by the following formula (1): ##STR00001##
wherein M.sup.1 and M.sup.2 each independently represent any one selected from the group consisting of a hydrogen atom, a monovalent metal atom, an alkaline earth metal atom and an ammonium ion, provided that M.sup.1 and M.sup.2 are not a hydrogen atom at the same time; X.sup.1 and X.sup.2 represent an organic group; m and n each independently represent the number of substituents; Z.sup.1 represents a hydrogen atom or an optionally substituted carbonyl group; Z.sup.2 represents an optionally substituted hydrocarbon group; Z.sup.3 represents a hydrogen atom or an optionally substituted carbonyl group; and when Z.sup.1 or Z.sup.3 is an optionally substituted carbonyl group, they optionally form a ring structure together with Z.sup.2, each independently.

The present invention relates to a liquid crystal alignment composition comprising first liquid crystal alignment polymer; second liquid crystal alignment polymer; and a cross-linking agent compound, a method for preparing a liquid crystal alignment film using the same, a liquid crystal alignment film and a liquid crystal display using the same.

Provided is a polyimide having a repeating unit represented by the following Formula (1):

##STR00001##

wherein R.sup.1 represents a tetravalent group; R.sup.2 represents a divalent group; provided that at least one of R.sup.1's is represented by the following Formula (2); and among R.sup.2's, at least one group is represented by the following Formula (3), and at least one other group is represented by the following Formula (4):

##STR00002##

Disclosed herein are a polyimide film for graphite sheets and a graphite sheet manufactured using the same. The polyimide film is fabricated by imidizing a precursor composition including: a polyamic acid prepared by reacting a dianhydride monomer with a diamine monomer; and an organic solvent, wherein the diamine monomer includes about 30 mol % to about 70 mol % of 4,4′-methylenedianiline and about 30 mol % to about 70 mol % of 4,4′-oxydianiline based on the total number of moles of the diamine monomer, 4,4′-methylenedianiline and 4,4′-oxydianiline being present in total in an amount of about 85 mol % or more based on the total number of moles of the diamine monomer.

In order to provide a resin composition excellent in pattern processability and film strength, a resin composition film, and a semiconductor device using these, there is provided a resin composition including (A) a polymer compound, (B) a cationic polymerizable compound, and (C) a cationic polymerization initiator, in which (A) the polymer compound has a carboxylic acid residue at a molecular chain terminal.

The present invention provides a polyimide film, which comprises a polyimide having a structure represented by formula (I):

##STR00001## in which A is a residue group of an aromatic diamine containing a sulfonyl group in its main chain moiety, R.sub.1 is a residue group of an aromatic dianhydride, R.sub.2 is a residue group of an aliphatic dianhydride, m and n are each independently a positive integer, a diamine monomer constituting the polyimide is only composed of the aromatic diamine containing the sulfonyl group in its main chain moiety, and the polyimide is surface-dried at 75° C. to 155° C. in the process of forming the polyimide film. The polyimide film of the present invention has transparency and UV absorption properties.