An alignment film composition includes a copolymer of a dianhydride-based compound and a diamine-based compound, and a cross-linker. The copolymer has a structure represented by Chemical Formula Ia or Chemical Formula Ib, and the cross-linker is represented by Chemical Formula IIa or Chemical Formula IIb:

##STR00001##

A polyimide resin containing a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2), a content ratio of the repeating structural unit of formula (1) with respect to the total of the repeating structural unit of formula (1) and the repeating structural unit of formula (2) being 20 to 70 mol %, and the polyimide resin having a chain aliphatic group having from 5 to 14 carbon atoms at an end thereof:

wherein R.sub.1 represents a divalent group having from 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure; R.sub.2 represents a divalent chain aliphatic group having from 5 to 16 carbon atoms; and X.sub.1 and X.sub.2 each independently represent a tetravalent group having from 6 to 22 carbon atoms containing at least one aromatic ring.

A high-temperature-stable spin-on-carbon (“SOC”) material that fills topography features on a substrate while planarizing the surface in a one-step, thin layer coating process is provided. The material comprises low molecular weight polyimides or diimides that are pre-imidized in solution rather than on the wafer. The SOC layers can survive harsh CVD conditions and are also SC1 resistant, especially on TiN and SiOx surfaces.

Provided are a block polyamide acid imide having an appropriate solubility in aqueous alkaline solutions, and block polyimides that are obtained using same and have high transparency and a low coefficient of linear thermal expansion (low CTE). The block polyimide comprises blocks configured from repeating structural units represented by defined formula (1A) and blocks configured from repeating structural units represented by defined formula (1B).

Provided is a resin composition that has a low viscosity before curing, and is capable of being turned into a cured product having superior dielectric properties (low relative permittivity and low dielectric tangent), a low elastic modulus and also an excellent heat resistance. The resin composition is a heat-curable citraconimide resin composition containing:

(A) a citraconimide compound having a saturated or unsaturated divalent hydrocarbon group(s) having 6 to 100 carbon atoms;

(B) an epoxy resin having at least two epoxy groups in one molecule; and

(C) a reaction promoter,

wherein a mass ratio between the components (A) and (B) is (A):(B)=99:1 to 1:99.

A resin film, in which at least one of polyimide layers is a non-thermoplastic polyimide layer having a linear thermal expansion coefficient of 1×10.sup.−6 to 30×10.sup.−6 (1/K), is shown. The non-thermoplastic polyimide layer is composed of a polyimide which is produced by reacting an anhydride component containing an aromatic tetracarboxylic anhydride with a diamine component, wherein the diamine component contains both a dimer acid-type diamine produced by replacing each of two terminal carboxyl groups in a dimer acid with a primary aminomethyl or amino group and an aromatic diamine, and the dimer acid-type diamine is contained in an amount of 1 to 15 mol % relative to the whole diamine component.

A light, flexible, and tough thin film having high total light transmittance that can be formed on various three dimensional shapes, and also provides a stably driven tactile sensor, which is an electronic device having the switching function thereof, is provided. The tactile sensor is formed on a polyimide thin film having high total light transmittance, thermal resistance, and a polar component of surface free energy with a specific value, and has a switching device that emits a voltage signal which, through an electronic circuit for controlling noise, stably drives another device. This tactile sensor has a curved or flat surface and has a first electrode, a ferroelectric layer, and a second electrode formed over the polyimide thin film. The switching device as a tactile sensor can drive another device merely by a light touch with a finger, and can be manufactured at a high non-defective rate.

The present application provides a flexible substrate and a method of manufacturing the same. The flexible substrate includes a base substrate, the flexible substrate is a polyimide film, wherein the polyimide film comprises polyimide having a structural formula of

##STR00001##

and the polyimide has a rigid segment and a flexible segment. The polyimide film is divided into rigid regions and a flexible region, wherein the rigid region is mainly constituted by the rigid segment, and the flexible region is mainly constituted by the flexible segment. Because the polyimide has the rigid segment and the flexible segment, it is used in flexible substrates.

The purpose of the present invention is to provide a medical film having excellent transparency, heat resistance, and solvent resistance. This medical film is a medical film including a heat-resistant resin having a glass transition temperature measured by thermomechanical analysis TMA of 190° C. or higher wherein the medical film has a total light transmittance of 80% or higher at a thickness of 10 μm and a b* value in the L*a*b* color system of 10 or lower.

A polyimide that is a reaction product of a diamine represented by Chemical Formula 1, a diamine represented by Chemical Formula 2, and a tetracarboxylic dianhydride represented by Chemical Formula 3: ##STR00001## wherein, in Chemical Formulae 1 to 3, L.sup.1, L.sup.2, R.sup.a to R.sup.f, m, R.sup.2, R.sup.10, R.sup.12, R.sup.13, n7, and n8 are the same as defined in the specification.