Abstract: A method for controlling a polyimide backbone structure, including: in preparation of a polyimide through reaction of a diamine component and (1S,2R,4S,5R)-cyclohexanetetracarboxylic dianhydride in an organic solvent containing an aprotic amide solvent and a lactone solvent, adjusting one or more of reaction conditions of a mass ratio of the aprotic amide solvent and the lactone solvent, a reaction temperature, a reaction time, and an amount of the aprotic amide solvent, so as to convert a cis-structure derived from the (1S,2R,4S,5R)-cyclohexanetetracarboxylic dianhydride in the formed polyimide to a trans-structure derived from (1R,2S,4S,5R)-cyclohexanetetracarboxylic dianhydride corresponding to the reaction conditions, thereby controlling a proportion of the trans-structure.

Abstract: The present invention is directed to a polyimide resin comprising a structural unit A derived from a tetracarboxylic dianhydride and a structural unit B derived from a diamine, wherein the structural unit A contains a structural unit (A-1) derived from 4,4?-(hexafluoroisopropylidene)diphthalic anhydride, and the structural unit B contains a structural unit derived from an aliphatic diamine, a polyimide resin composition comprising the polyimide resin and inorganic nanoparticles, and a polyimide film comprising the polyimide resin or the polyimide resin composition. Provided are a polyimide resin and a polyimide resin composition, each of which can form a film having not only a heat resistance, and colorlessness and transparency but also low water absorption properties, and a polyimide film.

Abstract: Disclosed are a polyimide resin containing a structural unit represented by the following formula (1-1), and a polyimide film containing a structural unit represented by the following formula (1-2) and having a thickness of 10 to 50 ?m. R1 and R2 in the formula (1-1) each independently represent any group of the following formulae (i) to (iv), R1 and R2 in the formula (1-2) each independently represent a group of the following formula (i) or formula (ii), and in these formulae, * bonds to the carbon with * in the formula (1-1) and the formula (1-2) and ** bonds to the carbon with ** in the formula (1-1) and the formula (1-2). A polyimide resin capable of forming a polyimide film excellent in transparency and having a low coefficient of linear thermal expansion, and a polyimide film having a lower coefficient of linear thermal expansion are provided.

Abstract: A polyimide containing a repeating unit represented by the following formula (I) and a repeating unit represented by the following formula (II). In the formula (II), R each independently represents a hydrogen atom, a fluorine atom, or a methyl group.

Abstract: An asymmetric membrane including a crosslinked polyimide resin, the crosslinked polyimide resin being formed by crosslinking a polyimide resin by a crosslinking agent; the polyimide resin including a structural unit (A) derived from tetracarboxylic dianhydride and a structural unit (B) derived from diamine; the structural unit (A) including a structural unit (A-1) derived from a compound represented by Formula (a-1); the structural unit (B) including a structural unit (B-1) derived from Formula (b-1), and a proportion of the structural unit (B-1) per 100 mol % of the structural unit (B) being from 0.1 to 50 mol %; and the crosslinking agent being a compound having not less than two functional groups that bond with carboxy groups. In Formula (b-1), Q1 and Q2 are each independently a group including an aromatic group, an aliphatic hydrocarbon group, and/or an alicyclic hydrocarbon group; X is a single bond or a particular group.

Abstract: Provided is a polyimide resin composition capable of forming a polyimide film which is excellent in transparency and heat resistance and has a low thermal linear expansion coefficient. The polyimide resin composition contains a polyimide resin produced by reacting (A) a tetracarboxylic dianhydride with (B) a diamine containing a phenolic hydroxyl group-containing diamine in an amount of from 5 to 100 mol % of the total diamine; and silica microparticles, in a ratio by mass of from 25/75 to 60/40.

Abstract: An asymmetric membrane including a crosslinked polyimide resin, the crosslinked polyimide resin being formed by crosslinking a polyimide resin by a crosslinking agent; the polyimide resin including a structural unit (A) derived from tetracarboxylic dianhydride and a structural unit (B) derived from diamine; the structural unit (A) including a structural unit (A-1) derived from a compound represented by Formula (a-1); the structural unit (B) including a structural unit (B-1) derived from Formula (b-1), and a proportion of the structural unit (B-1) per 100 mol % of the structural unit (B) being from 0.1 to 50 mol %; and the crosslinking agent being a compound having not less than two functional groups that bond with carboxy groups. In Formula (b-1), Q1 and Q2 are each independently a group including an aromatic group, an aliphatic hydrocarbon group, and/or an alicyclic hydrocarbon group; X is a single bond or a particular group.

Abstract: The present invention is directed to a polyimide resin comprising a structural unit A derived from a tetracarboxylic dianhydride and a structural unit B derived from a diamine, wherein the structural unit A contains a structural unit (A-1) derived from 4,4?-(hexafluoroisopropylidene)diphthalic anhydride, and the structural unit B contains a structural unit derived from an aliphatic diamine, a polyimide resin composition comprising the polyimide resin and inorganic nanoparticles, and a polyimide film comprising the polyimide resin or the polyimide resin composition. Provided are a polyimide resin and a polyimide resin composition, each of which can form a film having not only a heat resistance, and colorlessness and transparency but also low water absorption properties, and a polyimide film.

Abstract: A polyimide resin including a structural unit A derived from a tetracarboxylic dianhydride and a structural unit B derived from a diamine compound, wherein the structural unit A includes at least one of a structural unit (A-1) derived from a compound represented by the following formula (a-1), a structural unit (A-2) derived from a compound represented by the following formula (a-2), and a structural unit (A-3) derived from a compound represented by the following formula (a-3), the structural unit B comprises a structural unit (B-1) derived from a compound represented by the following formula (b-1), a proportion of the structural unit (B-1) in the structural unit B is 60 mol % or more, and the polyimide resin has a glass transition temperature of higher than 410° C.: wherein X and Y in the formula (b-1) each independently are a hydrogen atom, a methyl group, a chlorine atom, or a fluorine atom.

Abstract: A method for controlling a polyimide backbone structure, including: in preparation of a polyimide through reaction of a diamine component and (1S,2R,4S,5R)-cyclohexanetetracarboxylic dianhydride in an organic solvent containing an aprotic amide solvent and a lactone solvent, adjusting one or more of reaction conditions of a mass ratio of the aprotic amide solvent and the lactone solvent, a reaction temperature, a reaction time, and an amount of the aprotic amide solvent, so as to convert a cis-structure derived from the (1S,2R,4S,5R)-cyclohexanetetracarboxylic dianhydride in the formed polyimide to a trans-structure derived from (1R,2S,4S,5R)-cyclohexanetetracarboxylic dianhydride corresponding to the reaction conditions, thereby controlling a proportion of the trans-structure.

Abstract: A polyimide resin contains repeating structural units represented by formulas (1) and (2), wherein the content of the repeating structural unit represented by formula (2) relative to the total of the repeating structural unit represented by formula (1) and the repeating structural unit represented by formula (2) falls within a specific range and the content of the divalent group represented by the following structural formula (B1) falls within a specific range: X1 represents a tetravalent group containing an alicyclic hydrocarbon structure and having a carbon number of from 4 to 22. X2 represents a tetravalent group containing an aromatic ring and having a carbon number of from 6 to 22.

Abstract: Disclosed are a polyimide resin containing a structural unit represented by the following formula (1-1), and a polyimide film containing a structural unit represented by the following formula (1-2) and having a thickness of 10 to 50 ?m. R1 and R2 in the formula (1-1) each independently represent any group of the following formulae (i) to (iv), R1 and R2 in the formula (1-2) each independently represent a group of the following formula (i) or formula (ii), and in these formulae, * bonds to the carbon with * in the formula (1-1) and the formula (1-2) and ** bonds to the carbon with ** in the formula (1-1) and the formula (1-2). A polyimide resin capable of forming a polyimide film excellent in transparency and having a low coefficient of linear thermal expansion, and a polyimide film having a lower coefficient of linear thermal expansion are provided.

Abstract: The present invention provides a polyimide resin composition capable of forming a film having heat resistance and transparency and, in addition thereto, mechanical strength, surface hardness and flex resistance, a polyimide resin, a polyimide film and a laminate. The present invention includes: a polyimide resin composition containing a polyimide resin that has structural units represented by specific structures in a specific ratio, containing silica fine particles; the polyimide resin; a polyimide film; and a laminate.

Abstract: A polyimide resin contains repeating structural units represented by formulas (1) and (2), wherein the content of the repeating structural unit represented by formula (2) relative to the total of the repeating structural unit represented by formula (1) and the repeating structural unit represented by formula (2) falls within a specific range and the content of the divalent group represented by the following structural formula (B1) falls within a specific range: X1 represents a tetravalent group containing an alicyclic hydrocarbon structure and having a carbon number of from 4 to 22. X2 represents a tetravalent group containing an aromatic ring and having a carbon number of from 6 to 22.

Abstract: Provided is a polyimide resin composition capable of forming a polyimide film which is excellent in transparency and heat resistance and has a low thermal linear expansion coefficient. The polyimide resin composition contains a polyimide resin produced by reacting (A) a tetracarboxylic dianhydride with (B) a diamine containing a phenolic hydroxyl group-containing diamine in an amount of from 5 to 100 mol % of the total diamine; and silica microparticles, in a ratio by mass of from 25/75 to 60/40.

Abstract: The present invention provides a process for producing a transparent heat-resistant gas-barrier film capable of exhibiting a good gas-barrier property and maintaining good properties even after heat-treated at a temperature of 250° C. or higher, in a simple manner at low costs without need of a large size facility and a number of steps. The process for producing a transparent heat-resistant gas-barrier film according to the present invention includes the steps of coating a polysilazane-containing solution onto at least one surface of a transparent polyimide film formed of a polyimide containing a specific repeated unit; and calcining the coated solution at a temperature of 180° C. or higher to laminate a silicon oxide layer obtained by the calcination on the transparent polyimide film.

Abstract: The present invention provides a process for producing a transparent heat-resistant gas-barrier film capable of exhibiting a good gas-barrier property and maintaining good properties even after heat-treated at a temperature of 250° C. or higher, in a simple manner at low costs without need of a large size facility and a number of steps. The process for producing a transparent heat-resistant gas-barrier film according to the present invention includes the steps of coating a polysilazane-containing solution onto at least one surface of a transparent polyimide film formed of a polyimide containing a specific repeated unit; and calcining the coated solution at a temperature of 180° C. or higher to laminate a silicon oxide layer obtained by the calcination on the transparent polyimide film.