An anisotropic electro-conductive film having high reliability, which electrically connects circuit electrodes having a fine pattern. The anisotropic film contains an insulating resin and particle groups. The particle groups are groups of particles in which a plurality of particles are bound together with a binder. The particle groups are regularly arranged with an interval of 1 m to 1,000 m.

A method of making a polyimide (PI)-based material. In one embodiment, the method begins by dispersing a polyamic acid (PAA) oligomer and photo-initiator into a photo-reactive monomer to form a liquid resin. In contrast to the above-described prior art, the liquid resin is substantially devoid of any non-reactive solvents. Electromagnetic radiation is then applied (e.g., in a 3D printing operation) to solidify the liquid resin and to substantially form a interpenetrating polymer network (IPN) in which the PAA oligomer is entangled within the network formed by the photo-reactive monomer but remains substantially independent and un-crosslinked from the PAA oligomer. Thereafter, the PAA-based IPN is thermally cycled to form a polyimide-based IPN.

A resin composition containing a polyimide resin particle (A) and at least one selected from the group consisting of a thermoplastic resin (B) and a thermosetting resin (C), wherein the polyimide resin particle (A) contains 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 the formula (1) with respect to the total of the repeating structural unit of the formula (1) and the repeating structural unit of the formula (2) is 20 to 70 mol %, and the polyimide resin particle (A) has a volume average particle size D50 of 5 to 200 m. (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.) ##STR00001##

The embodiments provide a polyamide-imide-based film, which comprises a polyamide-imide-based polymer, wherein when the coefficients of thermal expansion in the MD direction and TD direction of the film are measured at an interval of 5 C. in a temperature range of 300 C. to 365 C., respectively, the temperature at which the coefficient of thermal expansion in the MD direction or the coefficient of thermal expansion in the TD direction changes from a positive value to a negative value is 330 C. to 345 C., a process for preparing the same, and a cover window and a display device comprising the same.