Abstract: A non-thermoplastic polyimide film contains non-thermoplastic polyimide. The non-thermoplastic polyimide has a 3,3?,4,4?-biphenyltetracarboxylic dianhydride residue, a 4,4?-oxydiphthalic anhydride residue, a p-phenylenediamine residue and a 1,3-bis(4-aminophenoxy)benzene residue. Where the content ratio of the 3,3?,4,4?-biphenyltetracarboxylic dianhydride residue is A1 mol %, the content ratio of the 4,4?-oxydiphthalic anhydride residue is A2 mol %, the content ratio of the p-phenylenediamine residue is B1 mol %, and the content ratio of the 1,3-bis(4-aminophenoxy)benzene residue is B2 mol %, the relationships of A1+A2?80, B1+B2?80 and (A1+B1)/(A2+B2)?3.50 are satisfied.

Abstract: A multi-layered polyimide film includes a non-thermoplastic polyimide layer, and an adhesive layer that is disposed on at least one surface of the non-thermoplastic polyimide layer and contains polyimide. A dielectric loss tangent of the non-thermoplastic polyimide layer at a frequency of 10 GHz, a temperature of 23° C. and a relative humidity of 50% is 0.0030 or less. The adhesive layer has no melting peak or has a melting heat of 1.0 J/g or less at a melting peak in a temperature range of 100° C. or higher and 420° C. or lower. The polyimide contained in the adhesive layer has one or more tetracarboxylic dianhydride residues selected from a pyromellitic dianhydride residue and a 3,3?,4,4?-biphenyltetracarboxylic dianhydride residue, and one or more diamine residues selected from a 1,3-bis(4-aminophenoxy)benzene residue and a 4,4?-diamino-2,2?-dimethylbiphenyl residue.

Abstract: A polyamic acid that has a fluorine atom content of 25 wt % or less and an amount of a fluorine-containing diamine in the polyamic acid is 70 mol % or more with respect to 100 mol % of a sum of diamine components. The total number of moles of tetracarboxylic acid component in the polyamic acid is 0.960 times or more and less than 1.000 time total number of moles of diamine component. The polyamic acid preferably has the structural unit represented by formula (1) and the structural unit represented by formula (2). The polyamic acid may contain trans-1,4-cyclohexanediamine as the diamine component.

Abstract: A polyamide acid of the present invention contains, as a diamine component, 2,2-bistrifluoromethylbenzidine and trans-1,4-cyclohexanediamine, and contains, as a tetracarboxylic acid dianhydride component, a pyromellitic acid anhydride and a 3,3,4,4-biphenyltetracarboxylic acid dianhydride. A ratio of the trans-1,4-cyclohexanediamine to a total amount of the diamine is preferably 0.5-40 mol %. A polyimide is obtained by dehydration ring closure of the polyamide acid.

Abstract: A polyamic acid that is a polyaddition reaction product of a diamine and a tetracarboxylic dianhydrides, according to one or more embodiments of the present invention. The polyamic acid contains 2?-bistrifluoromethylbenzidine as a diamine component in addition to 3,3?,4,4?-biphenyltetracarboxylic dianhydride and 9,9?-(3,4?-dicarboxyphenyl)fluorenic dianhydride as tetracarboxylic dianhydride components. The polyamic acid may include 9,9?-(3,4?-dicarboxyphenyl)fluorenic dianhydride in an amount ranging from 0.5 mol % or more to 10 mol % or less based on total amount of the tetracarboxylic anhydride.

Abstract: A polyamic acid according to one or more embodiments of the present invention contains a structural unit represented by general formula (1) and a structural unit represented by general formula (2). In general formula (1), the plurality of R1s are each independently a hydrogen atom, a monovalent aliphatic group or an aromatic group. In general formula (2), the plurality of R2s are each independently an alkyl group having 1-3 carbon atoms or an aryl group having 6-10 carbon atoms. In general formulas (1) and (2), X is a tetravalent organic group. In general formula (2), the plurality of Ys are each independently an alkylene group having 1-3 carbon atoms or an arylene group having 6-10 carbon atoms, and m is an integer of 51-199.

Abstract: A polyamic acid that has a fluorine atom content of 25 wt % or less and an amount of a fluorine-containing diamine in the polyamic acid is 70 mol % or more with respect to 100 mol % of a sum of diamine components. The total number of moles of tetracarboxylic acid component in the polyamic acid is 0.960 times or more and less than 1.000 time total number of moles of diamine component. The polyamic acid preferably has the structural unit represented by formula (1) and the structural unit represented by formula (2). The polyamic acid may contain trans-1,4-cyclohexanediamine as the diamine component.

Abstract: A polyamide acid of the present invention contains, as a diamine component, 2,2-bistrifluoromethylbenzidine and trans-1,4-cyclohexanediamine, and contains, as a tetracarboxylic acid dianhydride component, a pyromellitic acid anhydride and a 3,3,4,4-biphenyltetracarboxylic acid dianhydride. A ratio of the trans-1,4-cyclohexanediamine to a total amount of the diamine is preferably 0.5-40 mol %. A polyimide is obtained by dehydration ring closure of the polyamide acid.

Abstract: The present invention has an object to obtain a polyimide film that has a sufficiently smooth surface without peeling even in a case where the polyimide film is a thick film and that is excellent in adhesion to an inorganic substrate. An alkoxysilane-modified polyamic acid solution of the present invention contains: an alkoxysilane-modified polyamic acid; and a surface control agent, the alkoxysilane-modified polyamic acid solution having a specific viscosity, the alkoxysilane-modified polyamic acid being obtained by reacting a polyamic acid with an alkoxysilane compound containing an amino group, and the polyamic acid being obtained by reacting a diamine with a tetracarboxylic dianhydride.

Abstract: Provided are a nanosilica-containing polyamide acid and a nanosilica-containing polyimide. The nanosilica-containing polyamide acid contains a polyamide acid, which is a polymer of an alicyclic tetracarboxylic acid dianhydride and an aromatic diamine containing a carboxyl group, and nanosilica, and is excellent in heat resistance, low thermal expansion and transparency, and exhibits low double refraction. Also provided is a product or a member that meets requirements of high heat resistance and high transparency by using the nanosilica-containing polyamide acid and the nanosilica-containing polyimide.

Abstract: The present invention has an object to obtain a polyimide film that has a sufficiently smooth surface without peeling even in a case where the polyimide film is a thick film and that is excellent in adhesion to an inorganic substrate. An alkoxysilane-modified polyamic acid solution of the present invention contains: an alkoxysilane-modified polyamic acid; and a surface control agent, the alkoxysilane-modified polyamic acid solution having a specific viscosity, the alkoxysilane-modified polyamic acid being obtained by reacting a polyamic acid with an alkoxysilane compound containing an amino group, and the polyamic acid being obtained by reacting a diamine with a tetracarboxylic dianhydride.