Abstract: The present invention provides a polyimide film in which a parameter A for the relationship of the viscosity (V) of a polyamic acid solution, the number average molecular weight (Mn) of polyamic acid, and the thickness (T) of a polyimide film falls within a range from 0.4 to 1.13.

Abstract: 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.

Abstract: Disclosed herein is a polyimide film that is obtained by imidizing a polyamic acid solution containing two or more dianhydride components selected from the group consisting of 3,3?,4,4?-benzophenonetetracarboxylic dianhydride (BTDA), 3,3?,4,4?-biphenyltetracarboxylic dianhydride (BPDA), and pyromellitic dianhydride (PMDA), and a diamine component including m-tolidine and p-phenylenediamine (PPD) and has a glass transition temperature (Tg) of 320° C. or higher, a moisture absorption rate of 0.4% or less, and a dielectric dissipation factor (Df) of 0.004 or less.

Abstract: The present invention is a polyimide varnish for conductor coating, which provides a polyimide varnish comprising: a polyamic acid solution prepared through polymerization of at least one dianhydride monomer and at least one diamine monomer in an organic solvent; an aromatic carboxylic acid having four or more carboxyl groups; an alkoxy silane coupling agent; and an antioxidant, wherein the polyimide varnish has a solid content of 15 to 38 wt % on the basis of the total weight thereof, and a viscosity at 23° C. of 500 to 9,000 cP, and the coated material prepared from the polyimide varnish has a degree of softening resistance of 520° C. or higher, and a breakdown voltage (BDV) of 8 kV/mm or higher.

Abstract: The present disclosure provides a multilayer polyimide film in which the core layer is made of a non-thermoplastic polyimide resin comprising one or more imidization catalysts and one or more dehydrating agents, and the skin layer laminated on one or both surfaces of the core layer contains one or more imidization catalysts, but does not contain a dehydrating agent, and a method for manufacturing the same.

Abstract: The present invention provides: a graphite sheet polyimide film, which is derived from a first precursor composition comprising a first polyamic acid and comprises a sublimable inorganic filler and a spherical polyimide-based filler; a manufacturing method therefor; and a graphite sheet manufactured using the same.

Abstract: The present invention provides a method for preparing a high-performance graphite sheet by imidizing a polyamic acid resulting from a reaction of dianhydride monomer(s) and diamine monomer(s) to obtain a polyimide film; and carbonizing and/or graphitizing the polyimide film to obtain a high-performance graphite sheet, where the polyimide film contains 2 or more fillers having different average particle diameters, and the thermal conductivity of the graphite sheet is at least 1,400 W/m·K. Further, the present invention provides a graphite sheet obtained by the above method.

Abstract: The present invention provides a polyimide film comprising inorganic fillers, the inorganic fillers comprising: a first filler group having a particle diameter (D50) falling within the range of 2-2.7 ?m; and a second filler group having an average particle diameter (D50) falling within the range of 1-1.7 ?m, wherein each of the first and second filler groups satisfies relational expression 1, 0.7?(D90?D10)/(D50)?1.2, with respect to the particle diameter.

Abstract: The present invention provides a polyimide film comprising an inorganic filler, which comprises a first filler group having a diameter (D50) of 2-2.7 ?m and a second filler group having an average diameter (D50) of 1-1.7 ?m, wherein the polyimide film satisfies relation 1: 0.7?(D90?D10)/(D50)?1.2, which is about the respective diameters of the first filler group and the second filler group.

Abstract: Disclosed are a graphite sheet formed from a polyimide film having a molecular orientation ratio of at least about 1.25, and a method for producing the same.

Abstract: A polyimide composite film having good adhesion to a metal layer without deterioration in mechanical properties.

Abstract: The present invention provides: a method for manufacturing a polyimide film for a graphite sheet having improved thermal conductivity; and the polyimide film. The present invention also provides a graphite sheet having excellent thermal conductivity, which is manufactured using the polyimide film.

Abstract: The present invention provides: a graphite sheet polyimide film, which is derived from a first precursor composition comprising a first polyamic acid and comprises a sublimable inorganic filler and a spherical polyimide-based filler; a manufacturing method therefor; and a graphite sheet manufactured using the same.

Abstract: The present invention provides a graphite sheet polyimide film derived from a first precursor composition comprising a first polyamic acid, the polyimide film comprising a sublimable inorganic filler and a graphene-containing spherical polyimide-based filler.

Abstract: The present disclosure provides a polyimide film prepared from a precursor composition containing a polyamic acid and an organic solvent and having a value of (first FWHM?second FWHM)/(first FWHM+second FWHM) which is less than 0.4, a graphite sheet prepared from the polyimide film, and a method for preparing a graphite sheet.

Abstract: The present invention relates to a polyimide film and a preparation method thereof. According to the present invention, a polyamic acid solution having a high weight-average molecular weight may be obtained by adjusting viscosity and solid content of the polyamic acid solution, and thus, a desired polyimide film may be prepared therefrom. Furthermore, since a length of carbon chains rearranged during graphitization is increased, a graphite sheet having excellent thermal conductivity can be prepared from the polyimide film of the present invention. Also, since the polyimide film has improved windability by further including inorganic particles as a filler, it may facilitate the wind operation.

Abstract: The present invention provides a method for preparing a high-performance graphite sheet by imidizing a polyamic acid resulting from a reaction of dianhydride monomer(s) and diamine monomer(s) to obtain a polyimide film; and carbonizing and/or graphitizing the polyimide film to obtain a high-performance graphite sheet, where the polyimide film contains 2 or more fillers having different average particle diameters, and the thermal conductivity of the graphite sheet is at least 1,400 W/m·K. Further, the present invention provides a graphite sheet obtained by the above method.