Compound, polyamic acid, polyimide, varnish, and film

Abstract

Provided is a polyamic acid or polyimide which has a repeating structure represented by formula (5) or formula (9). In formula (5): n5 and n6 each independently represent the number of fluorine atoms and are an integer of 6-10; the total number of n5 and n6 is 6-20; t3 is 0 or 1; Y3 and Y4 each independently represent an alkylene group that may or may not have a substituent, a divalent group in which at least one carbon atom that is not bonded to a nitrogen atom in the alkylene group is substituted by a hetero atom, a carbonate group, a carbamate group, a urea group, an amide group, an ester group, a thiocarbonate group, a thiocarbamate group, a thioamide group, or a thiourea group, or an arylene group that may or may not have a substituent; and X1 represents a tetravalent organic group.

Description

Compounds, polyamic acids, polyimides, varnishes, and films

[0001] The present invention relates to compounds, polyamic acids, polyimides, varnishes, and films. This application claims priority to Japanese Patent Application No. 2025-051085, filed in Japan on March 26, 2025, the contents of which are incorporated herein by reference.

[0002] Polyimides are used in a variety of fields, primarily in the aerospace and electronics industries, as heat-resistant fibers, molded products, and adhesives, due to their excellent heat resistance, electrical properties, mechanical properties, and adhesive properties. When used, it is desirable that polyimides be easy to process. Therefore, there is a need for polyimides with excellent heat resistance and dimensional stability to facilitate processing. One method to improve heat resistance is to raise the glass transition temperature of the polyimide. Another method to improve dimensional stability is to reduce the coefficient of thermal expansion. Polyamic acid is used as a precursor for polyimides exhibiting the above-mentioned properties. It has high solubility in solvents and can be converted to polyimides through dehydration reactions in solution and heating after coating.

[0003] Patent Document 1 discloses a fluorinated amide compound having repeating units containing amide bonds, which is used to produce a film.

[0004] Patent No. 7096931

[0005] However, the films obtained from the fluorinated amide compounds described in the examples of Patent Document 1 do not have sufficient heat resistance and dimensional stability. The object of the present invention is to provide a polyamic acid or polyimide used to produce a film, wherein the resulting film has excellent heat resistance and dimensional stability; a polyimide that has excellent heat resistance and dimensional stability; a compound used to produce the polyamic acid and the polyimide; a varnish containing the polyamic acid or polyimide; and a film obtained from the varnish.

[0006] The present invention has the following aspects: [1] A compound represented by the following formula (1). In the above formula (1), n1 and n2 each represent the number of fluorine atoms, and are each independently an integer of 6 to 10, the sum of n1 and n2 is 6 to 20, and t1 is 0 or 1. [2] A compound represented by the following formula (2). In the above formula (2), n3 and n4 each represent the number of fluorine atoms, and are each independently an integer of 6 to 10, the sum of n3 and n4 is 6 to 20, t2 is 0 or 1, and Y １ and Y ２ are each independently an alkylene group that has no substituent or has one or more substituents, or a divalent group in which at least one carbon atom of the alkylene group that does not bond to a nitrogen atom is substituted with a heteroatom, a carbonate group, a carbamate group, a urea group, an amide group, an ester group, a thiocarbonate group, a thiocarbamate group, a thioamide group, or a thiourea group, or an arylene group that has no substituent or has one or more substituents. [3] The Y １ is an arylene group represented by the following formula (3), and the Y ２ is an arylene group represented by the following formula (4). The compound according to [2]. In the above formula (3) and formula (4), the substituents R １ and R ２ each independently represent a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an aryl group having 6 to 9 carbon atoms, m1 represents the number of R １ , m2 represents the number of R ２ , m1 and m2 are each independently an integer of 0 to 4, * ＮＨ２ is a bonding hand with an amino group, * １ and * ２ is a bonding hand with a polyfluorocyclohexylene group. When m1 is 2 or more, the plurality of R １ are the same or different. When m2 is 2 or more, the plurality of R ２ are the same or different. [4] A polyamic acid having a repeating structure represented by the following formula (5). In the above formula (5), n5 and n6 each represent the number of fluorine atoms, and are each independently an integer of 6 to 10, the sum of n5 and n6 is 6 to 20, t3 is 0 or 1, and Y３ and Y ４ Each of these is an alkylene group having or having no substituents, a divalent group in which at least one carbon atom not bonded to the nitrogen atom of the alkylene group is substituted with a heteroatom, carbonate group, carbamate group, urea group, amide group, ester group, thiocarbonate group, thiocarbamate group, thioamide group, or thiourea group, or an arylene group having or having no substituents, X １ is a tetravalent organic group. [5] The above Y ３ This is an arylene group represented by the following formula (6), and the Y ４ The compound described in [4] is an arylene group represented by the following formula (7). In formulas (6) and (7) above, substituent R ３ and R ４ Each of these independently represents a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a C6-C9 aryl group, and m3 is R ３ It represents the number of, and m4 is R ４ The numbers are represented, and each is an independent integer from 0 to 4, * Ｎ This is a bond with the nitrogen atom, * ３ and * ４ This is a bond with a polyfluorocyclohexylene group, * ５ This is a coupling. If m3 is 2 or more, multiple R ３ They are the same or different. If m4 is 2 or more, there are multiple R ４ They are the same or different. [6] The aforementioned X １ The polyamic acid described in [4] or [5] is represented by the following formula (8). In formula (8) above, * represents a bond. [7] A polyimide having a repeating structure represented by the following formula (9). In the above formula (9), n7 and n8 represent the number of fluorine atoms, each being an integer from 6 to 10 independently, the sum of the numbers of n7 and n8 being from 6 to 20, t4 being 0 or 1, Y ５ and Y ６Each of these is an alkylene group having or having no substituents, a divalent group in which at least one carbon atom not bonded to the nitrogen atom of the alkylene group is substituted with a heteroatom, carbonate group, carbamate group, urea group, amide group, ester group, thiocarbonate group, thiocarbamate group, thioamide group, or thiourea group, or an arylene group having or having no substituents, X ２ is a tetravalent organic group. [8] The above Y ５ This is an arylene group represented by the following formula (10), and the Y ６ The polyimide described in [7] is an arylene group represented by the following formula (11). In formulas (10) and (11) above, substituent R ５ and R ６ Each of these independently represents a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a C1-C4 alkyl group, a C1-C4 alkoxy group, or a C6-C9 aryl group, and m5 is R ５ It represents the number of, and m6 is R ６ The numbers are represented, and each is an independent integer from 0 to 4, * Ｎ This is a bond with the nitrogen atom, * ６ and * ７ This is a bond with a polyfluorocyclohexylene group, * ８ This is a coupling. If m5 is 2 or more, multiple R ５ They are the same or different. If m6 is 2 or more, there are multiple R ６ They are the same or different. [9] The aforementioned X ２ The polyimide described in [7] or [8], wherein the polyimide is represented by the following formula (12). In formula (12) above, * is a bonding bond.

[10] A varnish containing a polyamic acid or polyimide as described in any of [4] to [9].

[11] A film obtained from the varnish described in

[10] .

[0007] According to the present invention, it is possible to provide a polyamic acid or polyimide used for making a film, wherein the resulting film has excellent heat resistance and dimensional stability; a polyimide having excellent heat resistance and dimensional stability; a compound used for producing the polyamic acid and polyimide; a varnish containing the polyamic acid or polyimide; and a film obtained from the varnish.

[0008] The meanings and definitions of terms used in this invention are as follows: The weight-average molecular weight of a copolymer (hereinafter also referred to as "Mw") is the polystyrene-equivalent molecular weight obtained by measuring it by gel permeation chromatography using a calibration curve prepared using a standard polystyrene sample. The "~" indicating a numerical range means that the values ​​written before and after it are included as the lower and upper limits. "Perfluorization" means that all C-H bonds in a compound are replaced with C-F bonds. "Perfluoroalkyl group" is a group in which all C-H bonds of an alkyl group are replaced with C-F bonds. "Perfluoro(alkoxyalkyl) group" is a group in which all C-H bonds of an alkoxyalkyl group are replaced with C-F bonds. "Perfluoro compound" is a compound in which all C-H bonds of the compound are replaced with C-F bonds. "Polyfluorocyclohexylene group" is a group in which at least two C-H bonds of a cyclohexylene group are replaced with C-F bonds. "Halogen atom" refers to a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. "Trans-Trans" indicates that the stereochemistry of both cyclohexane rings in two single-bonded cyclohexane rings is Trans. "Trans-Cis" indicates that the stereochemistry of one cyclohexane ring in two single-bonded cyclohexane rings is Trans, and the stereochemistry of the other cyclohexane ring is Cis. "Cis-Cis" indicates that the stereochemistry of both cyclohexane rings in two single-bonded cyclohexane rings is Cis. In this specification, each component may be represented by a single substance or by a combination of two or more substances. When two or more substances are used in combination for each component, the content of that component refers to the total content of the combined substances unless otherwise specified.

[0009] <Compounds, polyamic acids, and polyimides> <Compound represented by formula (1)> The compound represented by formula (1) in this embodiment (hereinafter also referred to as "compound (1)") is shown below.

[0010]

[0011] In formula (1) above, n1 and n2 represent the number of fluorine atoms and are each an integer from 6 to 10. 8 to 10 is preferred, 9 to 10 is more preferred, and 10 is even more preferred. The sum of the numbers of n1 and n2 is from 6 to 20, 7 to 20 is preferred, 8 to 20 is more preferred, 9 to 20 is even more preferred, and 10 to 20 is particularly preferred. Note that when t1 = 0, n2 = 0. When the sum of the numbers of n1 and n2 is above the lower limit, the chemical stability of compound (1) is improved because it has many chemically stable C-F bonds. t1 is 0 or 1. When t1 is 0, formula (1) is represented by the following formula (1Aa).

[0012]

[0013] n1 in formula (1Aa) is the same as in formula (1). The 1,3-diiodide and 1,4-diiodide are preferred, the 1,4-diiodide is more preferred, and the Trans isomer of the 1,4-diiodide is even more preferred.

[0014] When t1 is 1, equation (1) is given by equation (1Bb) below.

[0015]

[0016] n1 and n2 in formula (1Bb) are the same as in formula (1). The 4,4'-diiodide, 4,3'-diiodide, and 4,2'-diiodide are preferred, the 4,3'-diiodide and 4,4'-diiodide are more preferred, the 4,4'-diiodide is even more preferred, and the Trans-Trans isomer of the 4,4'-diiodide is particularly preferred.

[0017] <Compound represented by formula (2)> The compound represented by formula (2) in this embodiment (hereinafter also referred to as "compound (2)") is shown below.

[0018] In formula (2) above, n3 and n4 represent the number of fluorine atoms and are each an integer from 6 to 10. 8 to 10 is preferred, 9 to 10 is more preferred, and 10 is even more preferred. The sum of the numbers of n3 and n4 is from 6 to 20, 7 to 20 is preferred, 8 to 20 is more preferred, 9 to 20 is even more preferred, and 10 to 20 is particularly preferred. Note that when t2 = 0, n4 = 0. If the sum of the numbers of n3 and n4 is above the lower limit, the chemical stability of compound (2) is improved because it has many chemically stable C-F bonds. １ and Y ２ This is Y in equation (9) described later. ５ and Y ６ It is similar to and similar to the group. t2 is 0 or 1. When t2 is 0, formula (2) is the following formula (2a).

[0019]

[0020] n3 in formula (2a) is the same as in formula (2). The 1,3-diamine and 1,4-diamine compounds are preferred, the 1,4-diamine compound is more preferred, and the Trans isomer of the 1,4-diamine compound is even more preferred.

[0021] When t2 is 1, equation (2) is given by equation (2b) below.

[0022]

[0023] n3 and n4 in formula (2b) are the same as in formula (2). The 4,4'-diamine, 4,3'-diamine, and 4,2'-diamine are preferred, the 4,4'-diamine and 4,3'-diamine are more preferred, the 4,4'-diamine is even more preferred, and the Trans-Trans isomer of the 4,4'-diamine is particularly preferred.

[0024] The aforementioned Y １ The Y is preferably an arylene group represented by the following formula (3), and ２ The preferred component is an arylene group represented by the following formula (4).

[0025]

[0026]

[0027] In formulas (3) and (4) above, substituent R １ and R ２ This is R in equations (10) and (11) described later. ５ and R ６ It is similar to, and similar bases are preferred. m1 and m2 are integers from 0 to 4. * ＮＨ２ This is a bond with an amino group, * １ and * ２ This is a bond with a polyfluorocyclohexylene group. If m1 is 2 or more, multiple R １ They are the same or different. If m2 is 2 or more, there are multiple R ２ They are either the same or different.

[0028] As compound (2), the compound represented by the following formula (2c) is preferred.

[0029]

[0030] <Polyamic acid having a repeating structure represented by formula (5)> The repeating structure represented by formula (5) is shown below. Note that the polyamic acid having a repeating structure represented by formula (5) in this embodiment is also simply called polyamic acid.

[0031]

[0032] In formula (5) above, n5 and n6 represent the number of fluorine atoms and are each an integer from 6 to 10, independently of each other. 8 to 10 is preferred, 9 to 10 is more preferred, and 10 is even more preferred. The sum of the numbers of n5 and n6 is from 6 to 20, preferably from 7 to 20, more preferably from 8 to 20, even more preferably from 9 to 20, and particularly preferred from 10 to 20. Note that when t3 = 0, n6 = 0. When the sum of the numbers of n5 and n6 is above the lower limit, a rigid skeleton derived from the polyfluorocyclohexylene group can be introduced into the polyamic acid. As a result, the molecules of the polyamic acid tend to be arranged regularly. Consequently, a lot of thermal energy is required for the molecules to move freely, so the glass transition temperature (hereinafter also referred to as "Tg") is high, resulting in excellent heat resistance. Furthermore, by suppressing the movement of the molecules, the rate of change in the size of the molecules due to thermal changes can be suppressed, thus reducing the coefficient of thermal expansion and resulting in excellent dimensional stability. Furthermore, in the wavelength band of 1260 to 1360 nm used in optical communication, the C-H bonds contained in the cyclohexylene group have absorption corresponding to the harmonics of stretching vibrations based on the C-H bond at wavelengths of 1100 to 1150 nm. Therefore, using a polyamic acid with a high concentration of C-H bonds in the cyclohexylene group as a waveguide material results in significant losses. On the other hand, the C-F bonds of the cyclohexylene group do not have absorption based on the C-F bond near the aforementioned wavelength range. Therefore, a polyamic acid with a high concentration of C-F bonds in the cyclohexylene group can be used as a waveguide material in the aforementioned wavelength band. In other words, if the value is above the lower limit, the content of C-H bonds in the cyclohexylene group can be reduced, improving the transparency of the polyamic acid in the wavelength band of 1260 to 1360 nm and reducing the refractive index. The average degree of polymerization of the repeating structure represented by formula (5) is preferably 20 to 3,000, more preferably 60 to 2,400, and even more preferably 100 to 1,500. If the molecular weight is above the lower limit, sufficient toughness is obtained for it to function as a self-supporting membrane. If it is below the upper limit, it can be handled as a solution without gelling. The average degree of polymerization can be calculated by dividing the weight-average molecular weight by the molecular weight within the repeating structure.

[0033] Y ３ This is Y in equation (9) described later. ５ It is similar to, and a similar group is preferred. Y４ This is Y in equation (9) described later. ６ It is similar to, and a similar group is preferred.

[0034] Furthermore, since the polyfluorocyclohexylene group does not contain carbon-carbon double bonds, the decomposition of the polyamic acid due to heat and chemical transformations originating from the carbon-carbon double bonds can be suppressed. As a result, the polyamic acid exhibits excellent heat resistance, dimensional stability, and transparency. t3 is either 0 or 1. When t3 is 0, equation (5) is represented by the following equation (5a).

[0035]

[0036] X in equation (5a) １ , Y ３ , Y ４ , and n5 are the same as in equation (5). Y ３ and Y ４ The preferred bond position of the polyfluorocyclohexylene group is at positions 1,3 or 1,4, with position 1,4 being more preferred. When the bond position is at position 1,4, the trans isomer is preferred.

[0037] When t3 is 1, equation (5) is given by equation (5b) below.

[0038]

[0039] X in equation (5b) １ , Y ３ , Y ４ n5 and n6 are the same as in equation (5). Y ３ and Y ４ The preferred bond position of the polyfluorocyclohexylene group is at the 4,2', 4,3', or 4,4' positions, more preferably at the 4,3' or 4,4' positions, and even more preferably at the 4,4' position. When the bond position is at the 4,4' position, the Trans-Trans isomer is preferred.

[0040] The aforementioned Y ３ The Y is preferably an arylene group represented by the following formula (6), and ４ The preferred component is an arylene group represented by the following formula (7).

[0041]

[0042]

[0043] In the above formulas (6) and (7), the substituent R ３ and R ４ are the same as R in formulas (10) and (11) described below ５ and R ６ , and the same groups are preferable. m3 and m4 are each an integer of 0 to 4. * Ｎ is a bond to a nitrogen atom, and * ３ and * ４ are each a bond to a polyfluorocyclohexylene group, and * ５ is a bond. When m3 is 2 or more, a plurality of R ３ are the same or different. When m4 is 2 or more, a plurality of R ４ are the same or different.

[0044] In the above formula (5), X １ is the same as X in formula (9) described below ２ , and the same groups are preferable.

[0045] Further, the X １ is preferably a tetravalent organic group represented by the following formula (8).

[0046]

[0047] When the X １ is represented by the above formula (8), examples of the repeating structure represented by formula (5) include the following formulas (5c) and (5d).

[0048]

[0049] In formula (5c), Y ３ , Y ４ , n5, n6, and t3 are the same as those in formula (5).

[0050]

[0051] In formula (5d), Y ３ , Y ４ , n5, n6, and t3 are the same as those in formula (5).

[0052] (Other Components) In addition to the repeating structure represented by formula (5), the polyamic acid may have other repeating structures, and a repeating structure represented by the following formula (5e) is preferred.

[0053]

[0054] In formula (5e), X ２ , R ７ , R ８ , Z ２ , Z ３ , m7, m8, and t5 are the same as those in formula (9f) described later, and the same groups or integers are preferred.

[0055] The proportion of the repeating structure represented by formula (5e) is preferably 10 to 100 mol%, more preferably 50 to 100 mol%, relative to the number of moles of the polyamic acid. The proportion of the repeating structure represented by formula (5e) is preferably 10 to 100 mol%, more preferably 50 to 100 mol%, relative to the number of moles of the repeating structure represented by formula (5). The repeating structure represented by formula (5) and the repeating structure represented by formula (5e) may be arranged randomly or may be arranged regularly.

[0056] The terminal structure of the polyamic acid is not particularly limited, and examples thereof include amino groups derived from compound (2) or a diamine other than compound (2), an acid anhydride derived from a compound represented by formula (15) described later, and a functional group obtained by chemically modifying said amino group or acid anhydride. The terminal structure may be subjected to chemical conversion as needed. The polyamic acid may also be a salt.

[0057] In addition to the diamine represented by formula (2), other diamines may be used as the repeating structure of the polyamic acid. Examples of other diamines include p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl Lusulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2-di(3-aminophenyl)propane, 2,2-di(4-aminophenyl)propane, 2-(3-aminophenyl)-2-(4-aminophenyl)propane, 1,1-di(3-aminophenyl)-1-phenylethane, 1,1-di(4- (aminophenyl)-1-phenylethane, 1-(3-aminophenyl)-1-(4-aminophenyl)-1-phenylethane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminobenzoyl)benzene, 1,3-bis(4-aminobenzoyl)benzene, 1,4-bis(3-aminobenzoyl)benzene, 1, 4-bis(4-aminobenzoyl)benzene, 1,3-bis(3-amino-α,α-dimethylbenzyl)benzene, 1,3-bis(4-amino-α,α-dimethylbenzyl)benzene, 1,4-bis(3-amino-α,α-dimethylbenzyl)benzene, 1,4-bis(4-amino-α,α-dimethylbenzyl)benzene, 2,6-bis(3-aminophenoxy)benzonitrile, 2,6-bis(3-aminophenoxy)pyridine, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-Bis(4-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, 2,2-bis[4-( 3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,3-bis[4-(4-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(4-aminophenoxy)benzoyl]benzene, 1,3-bis[4-(3-aminophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-aminophenoxy)-α,α-dimethyl [Benzyl]benzene, 1,4-bis[4-(3-aminophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(4-aminophenoxy)-α,α-dimethylbenzyl]benzene, 4,4'-bis[4-(4-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzophenone, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]diphenylsulfone, 4,4'-bis[4-(4-aminophenoxy)phenoxy]diphenyl Lusulfone, 3,3'-diamino-4,4'-diphenoxybenzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 3,3'-diamino-4-biphenoxybenzophenone, 6,6'-bis(3-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirovindan, 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirovindan, 1,3-bis(3-aminopropyl)tetramethyldisiloxane, 1,3-Bis(4-aminobutyl)tetramethyldisiloxane, α,ω-Bis(3-aminopropyl)polydimethylsiloxane, α,ω-Bis(3-aminobutyl)polydimethylsiloxane, bis(aminomethyl) ether, bis(2-aminoethyl) ether, bis(3-aminopropyl) ether, bis[(2-aminomethoxy)ethyl] ether, bis[2-(2-aminoethoxy)ethyl] ether, bis[2-(3-aminopropoxy)ethyl] ether, 1,2-bis(aminomethoxy)ethane, 1,2-bis(2-aminoethoxy)ethane , 1,2-bis[2-(aminomethoxy)ethoxy]ethane, 1,2-bis[2-(2-aminoethoxy)ethoxy]ethane, ethylene glycol bis(3-aminopropyl) ether, diethylene glycol bis(3-aminopropyl) ether, triethylene glycol bis(3-aminopropyl) ether, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diamino Decane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, trans-1,4-diaminocyclohexane, 1,2-di(2-aminoethyl)cyclohexane, 1,3-di(2-aminoethyl)cyclohexane, 1,4-di(2-aminoethyl)cyclohexane, bis(4-aminocyclohexyl)methane, 2,6-bis(aminomethyl)bicyclo[2.2.1]heptane, 2,5-bis(aminomethyl)bicyclo[2.2.1]heptane Butane, 1,4-diamino-2-fluorobenzene, 1,4-diamino-2,3-difluorobenzene, 1,4-diamino-2,5-difluorobenzene, 1,4-diamino-2,6-difluorobenzene, 1,4-diamino-2,3,5-trifluorobenzene, 1,4-diamino-2,3,5,6-tetrafluorobenzene, 1,4-diamino-2-(trifluoromethyl)benzene, 1,4-diamino-2,3-bis(trifluoromethyl)benzene, 1,4-diamino-2,5-bis(trifluoromethyl)benzene, 1,4-diamino-2,6-bis(trifluoromethyl)benzene, 1,4-diamino-2,3,5-tris(trifluoromethyl)benzene, 1,4-diamino-2,3,5,6-tetrakis(trifluoromethyl)benzene, 2-fluorobenzidine, 3-fluorobenzidine, 2,3-difluorobenzidine, 2.5-difluorobenzidine, 2,6-difluorobenzidine, 2,3,5-trifluorobenzidine, 2,3,6-trifluorobenzidine, 2,3,5,6-tetrafluorobenzidine, 2,2'-difluorobenzidine, 3,3'- Difluorobenzidine, 2,3'-difluorobenzidine, 2,2',3-trifluorobenzidine, 2,3,3'-trifluorobenzidine, 2,2',5-trifluorobenzidine, 2,2',6-trifluorobenzidine, 2,3',5-trifluorobenzidine, 2,3',6-trifluorobenzidine, 2,2',3,3'-tetrafluorobenzidine, 2,2',5,5'-tetrafluorobenzidine, 2,2',6,6'-tetrafluorobenzidine, 2,2',3,3',6,6'-hexafluorobenzidine, 2 ,2',3,3',5,5',6,6'-octafluorobenzidine, 2-(trifluoromethyl)benzidine, 3-(trifluoromethyl)benzidine, 2,3-bis(trifluoromethyl)benzidine, 2,5-bis(trifluoromethyl)benzidine, 2,6-bis(trifluoromethyl)benzidine, 2,3,5-tris(trifluoromethyl)benzidine, 2,3,6-tris(trifluoromethyl)benzidine, 2,3,5,6-tetrakis(trifluoromethyl)benzidine, 2,3'-bis(trifluoromethyl) Benzidine, 2,2',3-bis(trifluoromethyl)benzidine, 2,3,3'-tris(trifluoromethyl)benzidine, 2,2',5-tris(trifluoromethyl)benzidine, 2,2',6-tris(trifluoromethyl)benzidine, 2,3',5-tris(trifluoromethyl)benzidine, 2,3',6-tris(trifluoromethyl)benzidine, 2,2',3,3'-tetrakis(trifluoromethyl)benzidine, 2,2',5,5'-tetrakis(trifluoromethyl)benzidine and 2,2',6,Examples include, but are not limited to, 6'-tetrakis(trifluoromethyl)benzidine.

[0058] The weight-average molecular weight of the polyamic acid is preferably 10,000 to 1,000,000, more preferably 30,000 to 800,000, and even more preferably 50,000 to 500,000. If it is above the lower limit, the toughness of the resulting film tends to be higher.

[0059] The resulting polyamic acid can take the form of a film, a laminate of a polyamic acid film with another substrate, a coating film, a powder, beads, a molded body, a foam, or a varnish, with varnish or film being preferred.

[0060] <Varnish containing polyamic acid> A varnish containing polyamic acid contains at least polyamic acid and a solvent, wherein the amount of polyamic acid is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, relative to the total mass of the solvent and polyamic acid. When the amount is 10% by mass or more, it becomes easier to control the film thickness of the polyamic acid film obtained when manufacturing the polyamic acid film. As for the solvent, any solvent that dissolves polyamic acid is acceptable, and its structure is not particularly limited. Examples include the solvent contained in the varnish containing polyimide described later.

[0061] <Film obtained from varnish containing polyamic acid> The film thickness of the film obtained from varnish containing polyamic acid is preferably 0.1 to 50 μm, more preferably 1 to 30 μm. The glass transition temperature of the film is preferably 250°C or higher, more preferably 280°C or higher, and even more preferably 300°C or higher. If it is 280°C or higher, the film has excellent heat resistance and is easy to process. The coefficient of thermal expansion of the film is preferably 100 ppm / °C or less, more preferably 60 ppm / °C or less, and even more preferably 30 ppm / °C or less. If it is 30 ppm / °C or less, the film has excellent dimensional stability and is easy to process. The 5% mass loss temperature of the film is preferably 250 to 600°C, more preferably 300 to 550°C, and even more preferably 350 to 500°C.

[0062] <Polyimide having a repeating structure represented by formula (9)> The repeating structure represented by formula (9) is shown below. Note that the polyimide having a repeating structure represented by formula (9) in this embodiment is also simply called polyimide.

[0063]

[0064] In formula (9) above, n7 and n8 represent the number of fluorine atoms and are each an integer from 6 to 10, independently of each other. 8 to 10 is preferred, 9 to 10 is more preferred, and 10 is even more preferred. The sum of the numbers of n7 and n8 is from 6 to 20, 7 to 20 is preferred, 8 to 20 is more preferred, 9 to 20 is even more preferred, and 10 to 20 is particularly preferred. Note that when t4 = 0, n8 = 0. When the sum of the numbers of n7 and n8 is above the lower limit, a rigid skeleton derived from the polyfluorocyclohexylene group can be introduced into the polyimide. As a result, the molecules of the polyimide tend to be arranged regularly. Consequently, a lot of thermal energy is required for the molecules to move freely, so the glass transition temperature is high and the heat resistance is excellent. Furthermore, by suppressing the movement of the molecules, the rate of change in the size of the molecules due to thermal changes can be suppressed, so the coefficient of thermal expansion can be reduced and the dimensional stability is excellent. Furthermore, in the wavelength band of 1260 to 1360 nm used in optical communications, the C-H bonds contained in the cyclohexylene group have absorption corresponding to the harmonics of stretching vibrations based on the C-H bond at wavelengths of 1100 to 1150 nm. Therefore, using a polyimide with a high concentration of C-H bonds in the cyclohexylene group as a waveguide material results in significant losses. On the other hand, the C-F bonds of the cyclohexylene group do not have absorption based on the C-F bond near the aforementioned wavelength range. Therefore, a polyimide with a high concentration of C-F bonds in the cyclohexylene group can be used as a waveguide material in the aforementioned wavelength band. In other words, above the lower limit, the content of C-H bonds in the cyclohexylene group can be reduced, improving the transparency of the polyimide in the wavelength band of 1260 to 1360 nm and reducing the refractive index. The average degree of polymerization of the repeating structure represented by formula (9) is preferably 20 to 3,000, more preferably 60 to 2,400, and even more preferably 100 to 1,500. If the value is above the lower limit, sufficient toughness as a self-supporting membrane can be obtained. If the value is below the upper limit, it can be handled as a solution without gelling. The average degree of polymerization can be calculated by weight-average molecular weight / molecular weight within the repeating structure. The proportion of the repeating structure represented by formula (9) is preferably 10 to 100 mol%, and more preferably 50 to 100 mol%, relative to the number of moles of polyimide.Furthermore, since the polyfluorocyclohexylene group does not contain carbon-carbon double bonds, the decomposition of polyimide due to heat and chemical transformations originating from the carbon-carbon double bonds can be suppressed. As a result, the polyimide exhibits excellent heat resistance, dimensional stability, and transparency. t4 is either 0 or 1. When t4 is 0, equation (9) is represented by the following equation (9a).

[0065]

[0066] In equation (9a), X ２ , Y ５ , Y ６ , and n7 are the same as in equation (9). Y ５ and Y ６ The preferred bond position of the polyfluorocyclohexylene group is at positions 1,3 or 1,4, with position 1,4 being more preferred. When the bond position is at position 1,4, the trans isomer is preferred.

[0067] When t4 is 1, equation (9) is given by equation (9b) below.

[0068]

[0069] In equation (9b), X ２ , Y ５ , Y ６ n7 and n8 are the same as in equation (9). Y ５ and Y ６ The preferred bond position of the polyfluorocyclohexylene group is at the 4,2', 4,3', or 4,4' positions, more preferably at the 4,3' or 4,4' positions, and even more preferably at the 4,4' position. When the bond position is at the 4,4' position, the Trans-Trans isomer is preferred.

[0070] Y ５ and Y ６ Each of these is independently an alkylene group having or having no substituents, a divalent group in which at least one carbon atom not bonded to the nitrogen atom of the alkylene group is substituted with a heteroatom, a carbonate group, a carbamate group, a urea group, an amide group, an ester group, a thiocarbonate group, a thiocarbamate group, a thioamide group, or a thiourea group, or an arylene group having or having no substituents.

[0071] The alkylene group preferably has 2 to 10 carbon atoms, and more preferably 2 to 6 carbon atoms. The alkylene group may be linear, branched, or cyclic, or a combination of linear, branched, or cyclic. The alkylene group is preferably linear or cyclic, and more preferably cyclic. As for the substituent alkylene group, at least one hydrogen atom in the alkylene group is a heteroatom or -CF ３ Examples include groups substituted with a monovalent group having a heteroatom, and groups in which two hydrogen atoms bonded to the same carbon atom in the alkylene group are substituted with a divalent group having a carbon-heteroatom double bond. Examples of heteroatoms include halogen atoms, nitrogen atoms, oxygen atoms, sulfur atoms, boron atoms, or phosphorus atoms, with fluorine atoms, nitrogen atoms, and oxygen atoms being preferred. Examples of divalent groups having a carbon-heterodouble bond include carbonyl groups, imino groups, or thiocarbonyl groups, with carbonyl groups being preferred.

[0072] Examples of heteroatoms in a divalent group in which at least one carbon atom not bonded to the nitrogen atom of the alkylene group is substituted with a heteroatom, carbonate group, carbamate group, urea group, amide group, ester group, thiocarbonate group, thiocarbamate group, thioamide group, or thiourea group include nitrogen, oxygen, sulfur, boron, and phosphorus. Examples of the divalent group include a divalent group in which the methylene moiety of the alkylene group is substituted with a heteroatom. A divalent group in which at least one carbon atom not bonded to the nitrogen atom of the preferred alkylene group is substituted with a nitrogen, oxygen, or sulfur atom is preferred, and a divalent group in which one carbon atom not bonded to the nitrogen atom of the preferred alkylene group is substituted with an oxygen atom is more preferred. Furthermore, a divalent group is preferred in which at least one carbon atom not bonded to the nitrogen atom of the preferred alkylene group is substituted with a carbonate group, a carbamate group, a urea group, an amide group, or an ester group, and a divalent group is more preferred in which one carbon atom not bonded to the nitrogen atom of the preferred alkylene group is substituted with an amide group.

[0073] Examples of arylene groups include the group represented by the following formula (9c), and the group in which at least one carbon atom of the benzene ring in formula (9c) is substituted with a nitrogen atom.

[0074]

[0075] Z in equation (9c) ２ Z ３ , R ７ , R ８ , and t5 are the same as in equation (9f) described later. * Ｎ * represents a bond with a nitrogen atom, and * represents a bond with a polyfluorocyclohexylene group.

[0076] The aforementioned Y ５ The Y is preferably an arylene group represented by the following formula (10), and ６ The preferred component is an arylene group represented by the following formula (11).

[0077]

[0078]

[0079] In formulas (10) and (11) above, substituent R ５ and R ６ Each of these independently represents a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a C1-C4 alkyl group, a C1-C4 alkoxy group, or a C6-C9 aryl group, and m5 is R ５ It represents the number of, and m6 is R ６ The numbers are represented, and each is an independent integer from 0 to 4, * Ｎ This is a bond with the nitrogen atom, * ６ and * ７ This is a bond with a polyfluorocyclohexylene group, * ８ This is a coupling. If m5 is 2 or more, multiple R ５ They are the same or different. If m6 is 2 or more, there are multiple R ６ They are either the same or different.

[0080] Examples of alkyl groups having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, s-butyl group, t-butyl group, and cyclobutyl group, with methyl group being preferred.

[0081] Examples of alkoxy groups having 1 to 4 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, cyclopropoxy, n-butoxy, s-butoxy, t-butoxy, or cyclobutoxy groups, with methoxy being preferred.

[0082] Examples of aryl groups having 6 to 9 carbon atoms include phenyl groups, and phenyl groups having methyl, ethyl, propyl, methoxy, ethoxy, or propoxy groups as substituents. Furthermore, the aryl group may be a group in which one C-H bond on the heterocycle is substituted with the benzene ring bond in formulas (10) and (11). Examples of heterocycles include pyridine, pyrimidine, quinoline, or indole.

[0083] m5 is preferably 0 to 2, and more preferably 0. m6 is preferably 0 to 2, and more preferably 0.

[0084] X ２ Examples include the tetravalent organic group represented by the following formula (9d).

[0085]

[0086] Z in equation (9d) １ This is a single bond, -R ９ -, -O-, -S-, -C(=O)-, -SO ２ -, -OR ９ -, -R ９ -O-, -OC(=O)-R ９ -O-C(=O)-, or -C(R ９ｆ ) ２ - is one example. R ９ R is an alkylene group, an alkylene group containing at least one fluorine, or a polyfluoroalkylene group. ９ｆ * indicates fluorine or polyfluoroalkyl group. * indicates a bond.

[0087] Examples of alkylene groups include methylene group, ethylene group, n-propylene group, isopropylene group, cyclopropylene group, n-butylene group, s-butylene group, t-butylene group, cyclobutylene group, n-pentylene group, and n-hexylene group. Examples of alkylene groups containing at least one fluorine include alkylene groups in which at least one C-H bond of the alkylene group is substituted with C-F. Examples of polyfluoroalkylene groups include -[C(R ９ｆ ) ２ ] ｎ９ - (where n9 is an integer from 1 to 10) is an example. Note that the above R ９ｆ The above is R ９ｆ It is a similar group to -CF ２ -, - (CF ２ ) ２ -, - (CF ２ ) ３ -, - (CF ２ ) ６ -, -CF (CF ３ )-,-C(CF ３ ) ２ -, -C(C ２ F ５ ) ２ -, -[C(CF ３ ) ２ ] ２ - is preferable, -CF ２ -, -C (CF ３ ) ２ - or - (CF ２ ) ６ - is preferable.

[0088] As for polyfluoroalkyl groups, -(CF ２ ) ｎ１０ F (where n10 is an integer from 1 to 10) is an example, and -CF ３ , - (CF ２ ) ２ F, or -(CF ２ ) ３ F is preferred, -CF ３ This is preferable.

[0089] The aforementioned X ２ A tetravalent organic group represented by the following formula (12) is even more preferable.

[0090]

[0091] The aforementioned X ２ The tetravalent organic group is represented by formula (12), and the repeating structure represented by formula (9) is shown in formula (9e) below.

[0092]

[0093] Y in equation (9e) ５ , Y ６ n7, n8, and t4 are the same as in equation (9).

[0094] (Other components) Polyimide may have other repeating structures besides the repeating structure represented by formula (9), and the repeating structure represented by the following formula (9f) is preferred.

[0095]

[0096] In formula (9f), Z ２ and Z ３ Z in equation (9d) １ Similar to the above, and similar groups or single bonds are preferred. ７ and R ８ R in equation (9) ５ It is a group similar to the above, a fluorine atom, or the polyfluoroalkyl group. m7 and m8 are integers from 0 to 4, and t5 is an integer from 0 to 2. When t5 is 2, two Z ３ They are either the same or different.

[0097] The proportion of the repeating structure represented by formula (9f) is preferably 10 to 100 mol%, and more preferably 50 to 100 mol%, relative to the number of moles of polyimide. The proportion of the repeating structure represented by formula (9f) is preferably 10 to 100 mol%, and more preferably 50 to 100 mol%, relative to the number of moles of the repeating structure represented by formula (9). The repeating structure represented by formula (9) and the repeating structure represented by formula (9f) may be arranged randomly or regularly.

[0098] The terminal structure of the polyimide is not particularly limited, but examples include an amino group derived from compound (2) or a diamine other than compound (2), an acid anhydride derived from the compound represented by formula (15) described later, and a functional group obtained by chemically modifying the amino group or acid anhydride. The terminal structure may be chemically modified as needed.

[0099] In addition to the diamine represented by formula (2), other diamines may be used as the repeating structure of the polyimide. Examples of other diamines include p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl Lusulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2-di(3-aminophenyl)propane, 2,2-di(4-aminophenyl)propane, 2-(3-aminophenyl)-2-(4-aminophenyl)propane, 1,1-di(3-aminophenyl)-1-phenylethane, 1,1-di(4- (aminophenyl)-1-phenylethane, 1-(3-aminophenyl)-1-(4-aminophenyl)-1-phenylethane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminobenzoyl)benzene, 1,3-bis(4-aminobenzoyl)benzene, 1,4-bis(3-aminobenzoyl)benzene, 1, 4-bis(4-aminobenzoyl)benzene, 1,3-bis(3-amino-α,α-dimethylbenzyl)benzene, 1,3-bis(4-amino-α,α-dimethylbenzyl)benzene, 1,4-bis(3-amino-α,α-dimethylbenzyl)benzene, 1,4-bis(4-amino-α,α-dimethylbenzyl)benzene, 2,6-bis(3-aminophenoxy)benzonitrile, 2,6-bis(3-aminophenoxy)pyridine, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-Bis(4-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, 2,2-bis[4-( 3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,3-bis[4-(4-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(4-aminophenoxy)benzoyl]benzene, 1,3-bis[4-(3-aminophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-aminophenoxy)-α,α-dimethyl [Benzyl]benzene, 1,4-bis[4-(3-aminophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(4-aminophenoxy)-α,α-dimethylbenzyl]benzene, 4,4'-bis[4-(4-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzophenone, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]diphenylsulfone, 4,4'-bis[4-(4-aminophenoxy)phenoxy]diphenyl Lusulfone, 3,3'-diamino-4,4'-diphenoxybenzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 3,3'-diamino-4-biphenoxybenzophenone, 6,6'-bis(3-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirovindan, 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirovindan, 1,3-bis(3-aminopropyl)tetramethyldisiloxane, 1,3-Bis(4-aminobutyl)tetramethyldisiloxane, α,ω-Bis(3-aminopropyl)polydimethylsiloxane, α,ω-Bis(3-aminobutyl)polydimethylsiloxane, bis(aminomethyl) ether, bis(2-aminoethyl) ether, bis(3-aminopropyl) ether, bis[(2-aminomethoxy)ethyl] ether, bis[2-(2-aminoethoxy)ethyl] ether, bis[2-(3-aminopropoxy)ethyl] ether, 1,2-bis(aminomethoxy)ethane, 1,2-bis(2-aminoethoxy)ethane , 1,2-bis[2-(aminomethoxy)ethoxy]ethane, 1,2-bis[2-(2-aminoethoxy)ethoxy]ethane, ethylene glycol bis(3-aminopropyl) ether, diethylene glycol bis(3-aminopropyl) ether, triethylene glycol bis(3-aminopropyl) ether, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diamino Decane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, trans-1,4-diaminocyclohexane, 1,2-di(2-aminoethyl)cyclohexane, 1,3-di(2-aminoethyl)cyclohexane, 1,4-di(2-aminoethyl)cyclohexane, bis(4-aminocyclohexyl)methane, 2,6-bis(aminomethyl)bicyclo[2.2.1]heptane, 2,5-bis(aminomethyl)bicyclo[2.2.1]heptane Butane, 1,4-diamino-2-fluorobenzene, 1,4-diamino-2,3-difluorobenzene, 1,4-diamino-2,5-difluorobenzene, 1,4-diamino-2,6-difluorobenzene, 1,4-diamino-2,3,5-trifluorobenzene, 1,4-diamino-2,3,5,6-tetrafluorobenzene, 1,4-diamino-2-(trifluoromethyl)benzene, 1,4-diamino-2,3-bis(trifluoromethyl)benzene, 1,4-diamino-2,5-bis(trifluoromethyl)benzene, 1,4-diamino-2,6-bis(trifluoromethyl)benzene, 1,4-diamino-2,3,5-tris(trifluoromethyl)benzene, 1,4-diamino-2,3,5,6-tetrakis(trifluoromethyl)benzene, 2-fluorobenzidine, 3-fluorobenzidine, 2,3-difluorobenzidine, 2.5-difluorobenzidine, 2,6-difluorobenzidine, 2,3,5-trifluorobenzidine, 2,3,6-trifluorobenzidine, 2,3,5,6-tetrafluorobenzidine, 2,2'-difluorobenzidine, 3,3'- Difluorobenzidine, 2,3'-Difluorobenzidine, 2,2',3-Trifluorobenzidine, 2,3,3'-Trifluorobenzidine, 2,2',5-Trifluorobenzidine, 2,2',6-Trifluorobenzidine, 2,3',5-Trifluorobenzidine, 2,3',6-Trifluorobenzidine, 2,2',3,3'-Tetrafluorobenzidine, 2,2',5,5'-Tetrafluorobenzidine, 2,2',6,6'-Tetrafluorobenzidine, 2,2',3,3',6,6'-Hexafluorobenzidine, 2 ,2',3,3',5,5',6,6'-octafluorobenzidine, 2-(trifluoromethyl)benzidine, 3-(trifluoromethyl)benzidine, 2,3-bis(trifluoromethyl)benzidine, 2,5-bis(trifluoromethyl)benzidine, 2,6-bis(trifluoromethyl)benzidine, 2,3,5-tris(trifluoromethyl)benzidine, 2,3,6-tris(trifluoromethyl)benzidine, 2,3,5,6-tetrakis(trifluoromethyl)benzidine, 2,3'-bis(trifluoromethyl) Benzidine, 2,2',3-bis(trifluoromethyl)benzidine, 2,3,3'-tris(trifluoromethyl)benzidine, 2,2',5-tris(trifluoromethyl)benzidine, 2,2',6-tris(trifluoromethyl)benzidine, 2,3',5-tris(trifluoromethyl)benzidine, 2,3',6-tris(trifluoromethyl)benzidine, 2,2',3,3'-tetrakis(trifluoromethyl)benzidine, 2,2',5,5'-tetrakis(trifluoromethyl)benzidine and 2,2',6,Examples include, but are not limited to, 6'-tetrakis(trifluoromethyl)benzidine.

[0100] The weight-average molecular weight of the polyimide is preferably 10,000 to 1,000,000, more preferably 30,000 to 800,000, and even more preferably 50,000 to 500,000. If it is above the lower limit, the toughness of the resulting film tends to be higher.

[0101] The resulting polyimide can take the form of a film, a laminate of a polyimide film with another substrate, a coating film, a powder, beads, a molded body, a foam, or a varnish, with varnish or film being preferred.

[0102] <Polyimide-containing varnish> A polyimide varnish contains at least polyimide and a solvent, wherein the amount of polyimide is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 8% by mass or more, and particularly preferably 10% by mass or more, relative to the total mass of the solvent and polyimide. When the amount is 5% by mass or more, it becomes easier to control the film thickness of the polyimide film obtained when manufacturing the polyimide film.

[0103] As for the solvent, any solvent that dissolves polyimide is acceptable, and its structure is not particularly limited. Amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide (hereinafter also referred to as "DMAc"), and N-methyl-2-pyrrolidone (hereinafter also referred to as "NMP"), cyclic ester solvents such as γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, and α-methyl-γ-butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, glycol solvents such as triethylene glycol, phenol solvents such as m-cresol, p-cresol, 3-chlorophenol, and 4-chlorophenol, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, and dimethyl sulfoxide are preferred. Furthermore, other common organic solvents such as phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, tetrahydrofuran, dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, turpentine, mineral spirits, or petroleum naphtha-based solvents are examples, with cyclopentanone being preferred.

[0104] <Film obtained from varnish containing polyimide> The film thickness of the film obtained from varnish containing polyimide is preferably 0.1 to 50 μm, more preferably 1 to 30 μm. The glass transition temperature of the film is preferably 250°C or higher, more preferably 280°C or higher, and even more preferably 300°C or higher. If it is 280°C or higher, the film has excellent heat resistance and is easy to process. The coefficient of thermal expansion of the film is preferably 100 ppm / °C or less, more preferably 60 ppm / °C or less, and even more preferably 30 ppm / °C or less. If it is 30 ppm / °C or less, the film has excellent dimensional stability and is easy to process. The 5% mass loss temperature of the film is preferably 250 to 600°C, more preferably 300 to 550°C, and even more preferably 350 to 500°C.

[0105] <Applications of the film> Films obtained from varnish containing polyamic acid or polyimide can be used in heat-resistant fibers, molded articles, adhesives, polymer optical waveguides, or redistribution layer materials, and are preferably used as polymer optical waveguides or redistribution layer materials.

[0106] <Methods for producing compounds and polyimides> <Method for producing compound (1)>

[0107]

[0108] In equation (13), t1, n1, and n2 are the same as in equation (1).

[0109] Compound (1) of the present invention can be produced using compound (1a) as a raw material according to the reaction pathway in formula (13). Compounds (1b), (1c), and (1d) in formula (13) can be produced according to the production method in Japanese Patent Publication No. 2004-189611, but are not limited to the method in the above patent publication. Compound (1a) is commercially available or can be easily prepared by combining known synthesis reactions. R in compound (1aa), compound (1b), and compound (1c) ｆ R represents a perfluorinated monovalent organic group. ｆPreferably, the perfluoroalkyl group is a group in which an etheric oxygen atom is inserted between the carbon atoms of the perfluoroalkyl group, and more preferably, a perfluoroalkyl group having 2 to 18 carbon atoms, which may have an etheric oxygen atom inserted between the carbon atoms, or a perfluoro(alkoxyalkyl) group having 2 to 18 carbon atoms. R in compound (1aa) １０ This represents a monovalent organic group such as a halogen atom, a hydroxyl group, or an alkoxy group having 1 to 8 carbon atoms.

[0110] As for perfluoroalkyl groups, -(CF ２ ) ６ CF ３ , - (CF ２ ) ７ CF ３ , - (CF ２ ) ８ CF ３ , - (CF ２ ) ９ CF ３ , -CF (CF ２ CF ３ ) CF ２ CF ２ CF ２ CF ３ These are some examples.

[0111] Groups in which an etheric oxygen atom is inserted between the carbon atoms of a perfluoroalkyl group include the above-mentioned group in which an etheric oxygen atom is inserted between the carbon atoms, such as -CF(CF ３ ) [OCF ２ CF (CF ３ )] ｂ OCF ２ CF ２ CF ３ (b represents an integer from 0 to 5.), or -(CF ２ ) ｄ OCF ３ (d represents an integer from 1 to 8.) is preferred, -CF(CF ３ ) OCF ２ CF ２ CF ３ This is preferable.

[0112] R １０ A halogen atom is preferred, and a fluorine atom is more preferred.１０ When a hydroxyl group is used, it is preferable to use a condensing agent when producing compound (1b) described later. As the condensing agent, known condensing agents can be used, such as N,N'-dicyclohexylcarbodiimide, 2-methyl-6-nitrobenzoic anhydride, and 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium-3-oxidehexafluorophosphate (HATU).

[0113] -Method for producing compound (1b)- Compound (1b) can be produced by esterifying the two hydroxyl groups of compound (1a) using compound (1aa). The esterification reaction can be carried out under known esterification reaction conditions. The reaction temperature is usually preferably -50 to 100°C, and more preferably 25°C. The reaction time can be appropriately changed depending on the supply rate of the raw materials and the amount of compound actually reacted. The reaction pressure is preferably atmospheric pressure to 2 MPa (gauge pressure; hereafter, pressure will be expressed as gauge pressure). R １０ When halogen atoms are used, hydrogen halides are generated in the esterification reaction; therefore, alkali metal halides or trialkylamines may be present in the reaction system as hydrogen halide scavengers. The amount of hydrogen halide scavenger is preferably 1 to 10 times the number of moles of compound (1a). １０ If the atom is a fluorine atom or a chlorine atom, and no hydrogen fluoride or hydrogen chloride scavenger is used, it is preferable to carry out the reaction at a reaction temperature at which hydrogen fluoride or hydrogen chloride can vaporize, and to discharge the hydrogen fluoride or hydrogen chloride out of the reaction system accompanied by a nitrogen gas stream.

[0114] The amount of compound (1aa) is preferably 1 to 10 times the number of moles of compound (1a), and more preferably 1 to 5 times the number of moles. If the amount is above the lower limit, it is possible to suppress the remaining unreacted compound (1a) in the reaction product of the esterification reaction.

[0115] From the viewpoint of smoothly carrying out the fluorination reaction described later, it is preferable to purify the compound (1b) obtained by the esterification reaction. In particular, if the product of the esterification reaction contains compound (1a), it is preferable to remove compound (1a) by purification. Examples of purification methods include recrystallization, distillation, liquid-liquid extraction, or silica gel column chromatography.

[0116] -Method for producing compound (1c)- Compound (1c) can be produced by a fluorination reaction with compound (1b). The fluorination reaction is not particularly limited and can include a fluorination reaction using cobalt fluoride, an electrochemical fluorination reaction, and a liquid-phase fluorination reaction. However, a liquid-phase fluorination reaction, in which fluorine is reacted with compound (1b) in a liquid phase, is preferred because it yields a significantly higher yield.

[0117] In a liquid-phase fluorination reaction, the liquid phase may be the reaction substrate itself, but it is generally preferable to use an organic solvent or product that does not participate in the reaction as the liquid phase. Furthermore, it is preferable to use fluorine gas as is or fluorine gas diluted with an inert gas. Nitrogen gas and helium gas are preferred as the inert gas, with nitrogen gas being particularly preferred for economic reasons. The amount of fluorine gas in the nitrogen gas is not particularly limited, but from the viewpoint of reaction efficiency, 10% by volume or more is preferred, and 20% by volume or more is more preferred.

[0118] When using an organic solvent, an organic solvent that is inert to the liquid-phase fluorination reaction is preferred, and more preferably a solvent with high solubility of compound (1b) is used. A solvent capable of dissolving compound (1b) at a concentration of 1% by mass or more relative to the total mass of the solution is particularly preferred, and a solvent capable of dissolving at a concentration of 5% by mass or more is most preferred. The amount of organic solvent is preferably 5 times the mass of the total mass of compound (1b), and particularly 10 １ ~10 ５ Double the mass is preferable.

[0119] The reaction method for the liquid-phase fluorination reaction is not particularly limited. One method involves charging an organic solvent and compound (1b) into a reactor, stirring the reaction mixture, and then continuously supplying fluorine gas into the reaction mixture while the reaction is carried out. Another method involves charging an organic solvent into a reactor and stirring it, then continuously supplying fluorine gas at a constant flow rate, and then continuously supplying the raw material mixture of compound (1b) and organic solvent into the reaction mixture at a constant flow rate. Of these, the latter method is preferred in terms of reaction yield and selectivity. The fluorine gas used here may be fluorine gas diluted with an inert gas such as nitrogen gas.

[0120] In the liquid-phase fluorination reaction, it is preferable to maintain an excess equivalent amount of fluorine relative to the amount of hydrogen atoms contained in compound (1b). From the viewpoint of selectivity, it is more preferable to maintain an excess equivalent amount of fluorine relative to the moles of hydrogen atoms at 1.05 times the moles, and even more preferable to maintain an excess equivalent amount of fluorine at 2 times the moles. Furthermore, in order to maintain an excess equivalent amount of fluorine even at the start of the reaction, it is preferable to dissolve a sufficient amount of fluorine in the organic solvent used at the beginning of the reaction beforehand.

[0121] Furthermore, for the liquid-phase fluorination reaction, the reaction temperature is preferably -50 to 100°C, and more preferably -20 to 50°C, from the viewpoint of reaction yield, selectivity, and ease of industrial implementation. The reaction pressure for the fluorination reaction is not particularly limited, but from the viewpoint of reaction yield, selectivity, and ease of industrial implementation, atmospheric pressure to 2 MPa is preferred.

[0122] In liquid-phase fluorination reactions, hydrogen fluoride (HF) is produced as a by-product. To remove this HF, an HF scavenger (preferably NaF) is added to the reaction system. Next, it is preferable to contact the HF scavenger with the outlet gas at the reactor gas outlet, or to cool the outlet gas to condense and recover the HF. The gas after HF recovery may be returned to the reactor and reused. An example of a device for recovering condensed HF is a packed bed of NaF pellets. An example of a reactor is an autoclave. Alternatively, the HF may be carried out of the reaction system along with an inert gas such as nitrogen gas and treated with alkali. When using an HF scavenger, the amount is preferably 1 to 20 times the moles of the total number of hydrogen atoms present in compound (1b), and more preferably 1 to 5 times the moles.

[0123] The resulting compound (1c) may be used directly in the next step, or it may be purified to a high purity. Purification methods include distillation of the crude product under atmospheric or reduced pressure.

[0124] To ensure a smooth liquid-phase fluorination reaction when fluorinating compound (1b), the fluorine atom content of compound (1b) is preferably 20 to 70% by mass, and more preferably 40 to 70% by mass, relative to the total mass of compound (1b). Within this range, the solubility in the liquid phase during the fluorination reaction is significantly improved, leading to improved operability and reaction yield of the liquid-phase fluorination reaction, and resulting in superior economic efficiency. Furthermore, the molecular weight of compound (1b) is preferably 200 to 1100, and more preferably 300 to 800. Above the lower limit, the decomposition reaction of compound (1b) and compound (1c) due to the fluorination reaction can be suppressed. Below the upper limit, the handling of the compound and the purification of the product are easier.

[0125] -Method for producing compound (1d)- Compound (1d) can be produced by generating acyl fluoride through a decomposition reaction of the ester bond of compound (1c). Known techniques can be used for the decomposition reaction of the ester bond. The decomposition reaction of the ester bond is preferably carried out by thermal decomposition or decomposition in the presence of a nucleophile. The thermal decomposition reaction is preferably carried out by a gas-phase reaction or a liquid-phase reaction.

[0126] When compound (1c) is a compound with a low boiling point, the thermal decomposition reaction is preferably carried out by gas-phase thermal decomposition. In gas-phase thermal decomposition, it is preferable to carry out the decomposition reaction continuously in the gas phase, and to recover the resulting carbonyl fluoride by condensing it from the outlet gas. The reaction temperature for gas-phase thermal decomposition is preferably 50 to 350°C, more preferably 50 to 300°C, and particularly preferably 100 to 250°C. In gas-phase thermal decomposition, a metal salt catalyst may be used, and an inert gas that does not directly participate in the reaction may be present in the reaction system. As a metal salt catalyst, sodium fluoride or potassium fluoride can be used. As an inert gas, nitrogen gas or carbon dioxide gas can be used. The amount of inert gas added is preferably about 0.01 to 50 volume percent relative to the total amount of fluorination reaction products. If it is below the upper limit, the reduction in the amount of recovered product can be suppressed.

[0127] On the other hand, if compound (1c) is a compound with a high boiling point, the ester bond decomposition reaction is preferably carried out by liquid-phase thermal decomposition. The liquid-phase decomposition method is preferably carried out by heating the compound (1c) in liquid form. The product of the ester decomposition reaction may be withdrawn from the reactor all at once. Alternatively, compound (1d) having a carbonyl fluoride may be carried out by a reactive distillation method, taking advantage of the fact that compound (1d) usually has a lower boiling point than compound (1c), and carrying out the ester decomposition reaction using a reactor equipped with a distillation column, while withdrawing the product by distillation. The reaction temperature for the liquid-phase thermal decomposition method is preferably 50 to 300°C, and more preferably 100 to 250°C. The reaction pressure in the liquid-phase thermal decomposition method is not particularly limited. The liquid-phase thermal decomposition method may be carried out without a solvent or in the presence of a reaction solvent, and it is preferable to carry it out without a solvent. When a reaction solvent is used, it is preferable to use 0.1 to 10 times the mass of solvent relative to compound (1c). Examples of reaction solvents include ether compounds such as diglyme, tetraglyme, or tetrahydrofuran, and perfluoro compounds such as perfluoro-2,5-bistyrifluoromethyl-3,6-dioxanonate fluoride or perfluoro(-2-butyl-tetrahydrofuran).

[0128] When carrying out the decomposition reaction of ester bonds by reacting with a nucleophile in the liquid phase, the reaction may be carried out without a solvent or in the presence of a decomposition reaction solvent, but it is preferable to carry it out without a solvent. When the reaction is carried out without a solvent, the fluorinated reaction product itself acts as a solvent, and the effort of separating the solvent from the reaction product is eliminated, which is particularly preferable. When using a nucleophile, it is also preferable to carry out the reaction while distilling in a reaction apparatus equipped with a distillation column.

[0129] As a nucleophile, F － Preferably, F derived from alkali metal fluorides. － More preferable are NaF and NaHF. ２ KF or CsF are preferred, with NaF being more preferred in terms of economy and KF being more preferred in terms of reaction activity. － The amount of nucleophiles such as the above is preferably 1 to 500 mol%, more preferably 1 to 100 mol%, and particularly preferably 5 to 50 mol%, relative to the number of moles of compound (1c). The reaction temperature is preferably -30°C to 250°C.

[0130] As a nucleophile, F － When using this method, the decomposition reaction of the ester bond in compound (1c) involves compound (1d) and R ｆ C(=O)F(R) ｆ R in C(=O)F ｆ The above is R ｆ It is similar to the above. ) is produced. Compound (1d) in the ester decomposition reaction product and R ｆ It is preferable to separate C(=O)F. Distillation is preferred as the separation method. Furthermore, it is preferable to carry out the esterification reaction by reactive distillation. By using reactive distillation, a compound (1d) of extremely high purity can be obtained without separating and purifying the esterification reaction product.

[0131] -Method for producing compound (1)- Compound (1) can be produced by converting the acyl fluoride of compound (1d) to acyl iodide by an iodination reaction to obtain compound (1e), and then carrying out a decarbonylation reaction on compound (1e). The decarbonylation reaction may be carried out after purifying compound (1e), or the decarbonylation reaction may be carried out continuously without purifying compound (1e).

[0132] The iodation reaction is, － It is preferable to use a nucleophile having I derived from alkali metal iodides. － It is more preferable to use a nucleophile having [a specific characteristic]. As the alkali metal iodide, NaI, LiI, KI, or CsI are preferred, with LiI being more preferred. LiI exhibits high conversion efficiency from compound (1d) to compound (1e), and LiI can be easily removed from the product by filtration after the iodination reaction. Therefore, compound (1e) can be used in the decarbonylation reaction described later without further purification. － The amount of nucleophiles is preferably 100 to 500 mol%, more preferably 100 to 250 mol%, and particularly preferably 100 to 200 mol%, relative to the number of moles of compound (1d). The iodination reaction may be carried out without a solvent or in the presence of a reaction solvent, with solvent-free being preferred. When the reaction is carried out without a solvent, compound (1d) and compound (1e) themselves act as solvents, eliminating the need to separate the reaction solvent from the reaction product. The reaction temperature for the iodination reaction is preferably 100 to 200°C, more preferably 120 to 180°C. The reaction time is preferably 1 to 5 hours, more preferably 1 to 3 hours.

[0133] The decarbonylation reaction preferably uses a zero-valent metal. Examples of zero-valent metals include nickel, iron, magnesium, palladium, zinc, silver, or copper, but copper, silver, or nickel are preferred, and copper is more preferred from an economic standpoint. These metals are used in a form suitable for stirring and mixing, such as powder or fine flakes. The average particle size by volume is preferably 1 to 500 μm, and more preferably 5 to 100 μm. The decarbonylation reaction involves heating compound (1e) in contact with the zero-valent metal (for example, in a mixture with the zero-valent metal). The amount of zero-valent metal is preferably 1 to 200 mol%, and more preferably 1 to 100 mol%, relative to the number of moles of compound (1e). The reaction temperature is preferably 80 to 160°C, and more preferably 100 to 150°C. The reaction time is preferably 1 to 5 hours, and more preferably 1 to 3 hours.

[0134] The compound (1e) obtained by the decarbonylation reaction is likely to become the Trans isomer when the bond is at positions 1 and 4'. When the bond is at positions 4 and 4', it is likely to become the Trans-Trans isomer. When the bond is at positions 1 and 3, it is likely to become the Cis isomer.

[0135] Purification methods include recrystallization, liquid-liquid extraction, or silica gel column chromatography, and a combination of the above purification methods may be used. When liquid-liquid extraction is performed, it is preferable to use a 1 to 20% by mass aqueous solution of sodium bisulfite in order to remove iodine compounds other than compound (1e).

[0136] <Method for producing compound (2)> Compound (2) is produced by combining the iodine atoms of compound (1) with H-Y １ -NH ２ Formula (14) (hereinafter also referred to as "compound (14)"). Note that Y in formula (14) １ The same applies as in formula (2). It can be produced by a substitution reaction using ). Known techniques can be used for the substitution reaction. The substitution reaction is preferably a thermal substitution reaction or a substitution reaction carried out in the presence of a basic compound. The amount of compound (14) is preferably 200 to 1,000 mol%, and more preferably 200 to 400 mol%, relative to the number of moles of compound (1). If it is above the lower limit, compound (1) can be efficiently converted to compound (2). If it is below the upper limit, side reactions can be suppressed.

[0137] In substitution reactions carried out in the presence of a basic compound, known compounds can be used as the basic compound, such as sodium hydroxide, sodium bicarbonate, sodium carbonate, potassium hydroxide, potassium bicarbonate, potassium carbonate, and sodium dithionite (hereinafter referred to as "Na"). ２ S ２ O ４ Also known as ), sodium hydride, lithium diisopropylamide, or n-butyllithium are examples, with sodium hydroxide, sodium bicarbonate, or sodium carbonate being preferred. As the basic compound, a solution of a basic compound may be used. The amount of the basic compound is preferably 200 to 1,000 mol%, and more preferably 200 to 400 mol%, relative to the number of moles of compound (1).

[0138] The reaction temperature is preferably 0 to 60°C, and more preferably 10 to 40°C. The reaction time is preferably 1 to 24 hours, and more preferably 2 to 18 hours.

[0139] When using two or more basic compounds, the following combinations are preferred. Combination 1: Sodium bicarbonate and Na ２ S ２ O ４ Combination 2: Sodium carbonate and Na ２ S ２ O ４ Combination 3: Potassium carbonate and Na ２ S ２ O ４ In combination 1, the amount of sodium bicarbonate is Na ２ S ２ O ４ The amount of moles is preferably 100 to 400 mol%, and more preferably 100 to 200 mol%.

[0140] It is preferable to use an organic solvent, water, or a two-layer solvent system of an organic solvent and water as the solvent. The amount of solvent can be adjusted as needed, but it is preferably 1 to 10 mL and more preferably 3 to 8 mL per millimoles of compound (1). Examples of organic solvents include ether solvents, dichloromethane, chloroform, acetonitrile, toluene, N,N-dimethylformamide (hereinafter also referred to as "DMF"), dimethyl sulfoxide, N-methylpyrrolidone, etc. Examples of ether solvents include tetrahydrofuran (hereinafter also referred to as "THF"), dimethyl ether, diethyl ether, t-butyl methyl ether, or 1,4-dioxane, etc.

[0141] When using a two-layer solvent system, the substitution reaction can be carried out in accordance with known formal aromatic substitution reactions of perfluoroalkyl radicals, but is not limited to the above method. Preferred organic solvents for the two-layer solvent system are toluene or ether solvents, and more preferably THF or t-butyl methyl ether. The amount of organic solvent is preferably 1 to 10 mL, and more preferably 1 to 5 mL, per 1 mL of water.

[0142] When using two or more organic solvents, the following combinations are preferred: Combination 1: THF and t-butyl methyl ether Combination 2: THF and cyclohexyl methyl ether Combination 3: THF and 2-methyltetrahydrofuran In the case of Combination 1, the amount of THF is preferably 1 to 10 mL, and more preferably 1 to 2 mL, per 1 mL of t-butyl methyl ether.

[0143] When using a two-phase solvent system, it is preferable to use a phase transfer catalyst in order to promote the reaction and suppress side reactions. Examples of phase transfer catalysts include quaternary ammonium halides, quaternary ammonium bisulfate, quaternary ammonium hydroxide, or crown ethers, with quaternary ammonium bisulfate being preferred. The amount of phase transfer catalyst is preferably 1 to 30 mol%, and more preferably 1 to 20 mol%, relative to the number of moles of compound (1).

[0144] Examples of quaternary ammonium halides include tetrabutylammonium fluoride, tetrabutylammonium chloride, tetrabutylammonium bromide, or tetrabutylammonium iodide. Examples of quaternary ammonium hydrogen sulfate include tetramethylammonium hydrogen sulfate, tetraethylammonium hydrogen sulfate, tetrabutylammonium hydrogen sulfate, or tetrahexylammonium hydrogen sulfate, with tetrabutylammonium hydrogen sulfate being preferred. Examples of quaternary ammonium hydroxides include trimethylbenzylammonium hydroxide or tetramethylammonium hydroxide. Examples of crown ethers include 12-crown-4-ether, 15-crown-5-ether, 18-crown-6-ether, or 21-crown-7-ether.

[0145] Compound (2) is more likely to become the trans isomer when the bond is located at positions 1 and 4, regardless of whether compound (1e) is the trans or cis isomer. Also, when the bond is located at positions 4 and 4', it is more likely to become the trans-trans isomer, regardless of whether it is the trans-trans, trans-cis, or cis-cis isomer.

[0146] Purification methods include washing filtration, liquid-liquid separation, recrystallization, or silica gel column chromatography, and a combination of the above purification methods may be used. As the washing solution, it is preferable to use a fluorine-based washing solvent because compound (2) is difficult to dissolve. Examples of fluorine-based washing solvents include 1,1,2,2-Tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane or 1,1,1,2,2,3,3,4,4,5,5,6,6-Tridecafluorooctane, with 1,1,2,2-Tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane being preferred.

[0147] <Production of Polyamic Acid> Polyamic acid can be produced by polymerizing compound (2) and a compound represented by the following formula (15) (hereinafter also referred to as "acid anhydride (15)"). In addition to compound (2), other compounds may be included, and among the other compounds, the compound represented by the following formula (16) (hereinafter also referred to as "compound (16)") is preferred. The acid anhydride (15) may be a commercially available product or one produced by combining known reactions. During polymerization, it is preferable to use an organic solvent to promote the reaction, and it is more preferable to use a dehydrated organic solvent in order to suppress water-derived side reactions. The polymerized polyamic acid solution may be used as a varnish for film formation described later. The produced polyamic acid may be purified and used for the production of polyimide described later, or polyimide may be produced using the polyamic acid solution.

[0148] In formula (15), Z １ This is similar to formula (9d), and similar groups are preferred.

[0149] Examples of acid anhydrides (15) include 4,4-(hexafluoroisopropylidene)diphthalic anhydride (hereinafter also referred to as "6FDA"), pyromellitic anhydride (hereinafter also referred to as "PMDA"), 4,4'-biphthalic anhydride (hereinafter also referred to as "BPDA"), 4,4'-oxydiphthalic anhydride (hereinafter also referred to as "ODPA"), 4,4'-carbonyldiphthalic anhydride, or 4,4'-sulfonyldiphthalic anhydride (hereinafter also referred to as "DSDA"), with 6FDA being preferred.

[0150]

[0151] In formula (16), Z ２ Z ３ , R ７ , R ８ m7, m8, and t5 are the same as in formula (9f), and similar bases or integers are preferred.

[0152] As the compound represented by formula (16), the compound described in formula (17) below is preferred. The compound (α) in formula (17) is also called "TFMB". The compound (β) in formula (17) is also called "12FHDA".

[0153]

[0154] The amount of compound (2) is preferably 10 to 100 mol%, and more preferably 50 to 100 mol%, relative to the number of moles of acid anhydride (15). The amount of compound (16) is preferably 0 to 50 mol%, and more preferably 0 to 25 mol%, relative to the number of moles of acid anhydride (15). The total amount of compound (2) and compound (16) is preferably 80 to 120 mol%, and more preferably 100 mol%, relative to the number of moles of acid anhydride (15).

[0155] Examples of organic solvents include those exemplified in the method for producing compound (2), with DMF and ether-based solvents being preferred, and dehydrated DMF and dehydrated THF being more preferred. The amount of organic solvent is preferably 2 to 10 g, and more preferably 2 to 8 g, per 1 mmol of compound (2).

[0156] When using two or more organic solvents, the following combinations are preferred: Combination 1: THF and DMF Combination 2: THF and DMAc Combination 3: THF and NMP In the case of Combination 1, the amount of DMF is preferably 1 to 20 g, and more preferably 1 to 10 g, per 1 g of THF.

[0157] The polymerization temperature is preferably 0 to 100°C, and more preferably 10 to 40°C. The polymerization time is preferably 1 to 48 hours, and more preferably 5 to 24 hours.

[0158] When purifying polyamic acid compounds, purification methods include recrystallization, washing and filtration, liquid-liquid extraction, and silica gel column chromatography.

[0159] <Production of Polyimides> Polyimides can be produced by dehydrating and cyclizing polyamic acids. Examples of dehydration and cyclization include chemical imidation and thermal imidation, which can be carried out using known techniques. Chemical imidation, thermal imidation, or both can be carried out.

[0160] In the case of chemical imidation, it is preferable to use a chemical imidating agent to dehydrate and cyclize the polyamic acid compound. Examples of chemical imidating agents include acid anhydrides such as acetic anhydride, propionic anhydride, phthalic anhydride, and trifluoroacetic anhydride, with acetic anhydride being preferred. In addition, a reaction accelerator may be added to accelerate the reaction. Examples of reaction accelerators include tertiary amines such as trimethylamine, triethylamine, N,N-diisopropylethylamine, or N,N-dimethylaniline, and heterocyclic compounds such as pyridine, quinoline, isoquinoline, or imidazole, with pyridine being preferred. The liquid chemical imidating agent and reaction accelerator can also serve as a solvent for the polyamic acid compound.

[0161] The amount of chemical imidizing agent is preferably 100 to 2,000 mol%, and more preferably 100 to 1,000 mol%, relative to the number of moles of carboxyl groups in the polyamic acid. The amount of reaction accelerator is preferably 100 to 2,000 mol%, and more preferably 100 to 1,000 mol%, relative to the number of moles of carboxyl groups in the polyamic acid.

[0162] The following combinations of chemical imidizing agents and reaction accelerators are preferred: Combination 1: Acetic anhydride and pyridine Combination 2: Acetic anhydride and triethylamine Combination 3: Acetic anhydride and 4-dimethylaminopyridine In the case of Combination 1, the amount of acetic anhydride is preferably 2 to 10 mL, and more preferably 2 to 5 mL, per 1 mL of pyridine.

[0163] The reaction temperature is preferably 0 to 100°C, and more preferably 10 to 40°C. Chemical imidation allows the reaction to be carried out at a lower temperature compared to thermal imidation.

[0164] The resulting polyimide reaction solution can be precipitated by adding it dropwise to an excess amount of methanol. An example of the excess amount of methanol is 10 mL or more of methanol per 1 mL of the reaction solution. The precipitated polyimide can be isolated by filtering and vacuum drying. A drying temperature of 70 to 250°C is preferred.

[0165] <Film Formation> Film formation can be carried out using techniques known for polyimide. A solvent is added to the polyimide to obtain a varnish solution (the polyimide powder content relative to the total mass of the solution is preferably 1 to 30% by mass, and more preferably 10% by mass). The varnish is then applied to a substrate such as ceramic (glass, silicon, or alumina), metal (copper, aluminum, or stainless steel). A polyimide film is obtained by drying in a vacuum, in an inert gas such as nitrogen, or in air using hot air or infrared radiation at a temperature range of 20 to 400°C, preferably 50 to 350°C. The obtained polyimide film may be further vacuum dried.

[0166] In the case of thermal imidation, film formation can be carried out before the production of polyimide. A polyamic acid solution is applied to a substrate such as ceramic (glass, silicon, or alumina) or metal (copper, aluminum, or stainless steel), and dried in a vacuum, in an inert gas such as nitrogen, or in air using hot air or infrared rays at a temperature range of 40 to 500°C, preferably 50 to 400°C. Performing the above drying makes it easier to obtain a high-quality film. Polyimidation may also be carried out during drying. Then, with the edges of the film fixed, a polyimide film can be produced by thermal imidation at 100 to 500°C, more preferably 150 to 400°C, using hot air or infrared rays in a vacuum, in an inert gas such as nitrogen, or in air. In order to suppress the decomposition of polyimide, the thermal imidation time is preferably 1 to 48 hours, and more preferably 1 to 24 hours. In order to easily obtain a high-quality film, it is preferable to perform film formation gradually. A method of gradual film formation is to heat at a low temperature, then raise the temperature at a constant heating rate, and then heat at a high temperature. The low temperature is preferably 40 to 150°C, and more preferably 60 to 120°C. The heating time at the low temperature is preferably 10 to 120 minutes, and more preferably 30 to 90 minutes. The heating rate for thermal imidation is preferably 1 to 10°C / min. The high temperature is preferably 100 to 500°C, and more preferably 150 to 400°C. The heating time at the high temperature is preferably 1 to 48 hours, and more preferably 1 to 24 hours. In order to prevent oxidative degradation of the resulting polyimide film, it is desirable to perform thermal imidation in a vacuum or in an inert gas.

[0167] <Measurement Method> (Method for Measuring Glass Transition Temperature) The glass transition temperature (Tg) of the above-mentioned compounds and polyimides can be measured in accordance with the method for measuring glass transition temperature by differential scanning calorimetry (DSC) of differential scanning calorimetry (DSC) as specified in JIS K7121:1987. In this invention, the glass transition temperature refers to the midpoint glass transition temperature. Suitable measuring devices include differential scanning calorimeters (DSC 204 F1 Phoenix, manufactured by NETZSCH) or differential scanning calorimeters (NEXTA DSC 200, manufactured by Hitachi High-Tech Science Corporation), with differential scanning calorimeters (DSC 204 F1 Phoenix, manufactured by NETZSCH) being preferred. 5 to 10 mg of the compound, polyamic acid, or polyimide obtained by the above-described manufacturing method is placed in a measuring container and heated under a nitrogen atmosphere at a heating rate of 20°C / min to a temperature at least 30°C higher than the temperature at which the glass transition is completed, thereby creating a differential scanning calorimetry curve (hereinafter also referred to as the "DSC curve"). The temperature at the point where a line in the horizontal direction equidistant in the vertical direction from the extended lines of the high-temperature and low-temperature baselines in the horizontal direction of the DSC curve intersects with the curve of the step-like change portion of the glass transition is defined as the glass transition temperature.

[0168] (Method for measuring the linear thermal expansion coefficient) The linear thermal expansion coefficient (hereinafter also referred to as "CTE") of the above-mentioned compounds and polyimides can be measured in accordance with known methods for measuring linear thermal expansion coefficients. Examples of measuring devices include thermomechanical analyzers (TMA / SS7100, manufactured by Hitachi High-Tech Science Corporation) or thermomechanical analyzers (Thermo plus EVO2 TMA 8311, manufactured by Rigaku Corporation), with thermomechanical analyzers (TMA / SS7100, manufactured by Hitachi High-Tech Science Corporation) being preferred. When using a thermomechanical analyzer (TMA / SS7100, manufactured by Hitachi High-Tech Science Corporation) as the measuring device, the dimensional change is measured in the range of 100 to 200°C in tensile mode under a nitrogen atmosphere, with a heating rate of 5°C / min and a load of 10 mN, using a test piece (4 mm x 20 mm) of the compound, polyamic acid, or polyimide obtained by the above-mentioned manufacturing method. The dimensional change is defined as the difference between the maximum and minimum dimensions at 100-200°C. The linear thermal expansion coefficient is calculated as dimensional change (ppm) / 100 (°C).

[0169] <Method for measuring weight-average molecular weight> The weight-average molecular weight (Mw) of the above-mentioned compounds, polyamic acids, or polyimides can be measured in accordance with the method described in the examples below.

[0170] <Method for Measuring 5% Mass Loss Temperature> The 5% mass loss temperature (hereinafter also referred to as "Td5%") of the above-mentioned compound, polyamic acid, or polyimide can be measured in accordance with known methods for measuring 5% mass loss temperature. Examples of measuring devices include differential thermomass analyzers (NEXTA STA200RV, manufactured by Hitachi High-Tech Science Corporation) or differential thermomass analyzers (SDT 650, manufactured by T.A. Instruments Corporation), with differential thermomass analyzers (NEXTA STA200RV, manufactured by Hitachi High-Tech Science Corporation) being preferred. When using a differential thermomass analyzer (NEXTA STA200RV, manufactured by Hitachi High-Tech Science Corporation) as the measuring device, 5 to 10 mg of the compound, polyamic acid, or polyimide obtained by the above-described manufacturing method is placed in a measuring container, and the temperature is raised from 40°C to 1,000°C at a heating rate of 10°C / min under a nitrogen atmosphere. The sample mass at the measurement temperature of 40°C is used as the reference, and the measurement temperature at which the mass decreases by 5% relative to this reference mass is defined as the 5% mass loss temperature (Td5%).

[0171] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Examples 1 to 7 are examples, and Example 8 is a comparative example. １９ The yield obtained from the peak area ratio of the F-NMR spectrum is denoted as the NMR yield. Each yield represents the yield relative to the raw material for each process.

[0172] <Weight-average molecular weight; Mw> The weight-average molecular weight of the polyimides obtained in Examples 1-3, 7, and 8 was measured using a gel permeation chromatograph (HLC-8320GPC, Tosoh Corporation product name). The column used was (AsahiPak GF-7M HQ, Resonaq Corporation), and the developing solvent was LiBr (30 mmol / L) and H ３ PO ４A DMF solution containing (60 mmol / L) was used. The flow rate was 0.6 mL / min and the measurement temperature was 40°C. A differential refractive index (RI) detector was used as the detector. The polyimide was dissolved in DMF to prepare a sample solution in which the polyimide was 0.2% by mass relative to the total mass of the sample solution described below. 50 μL of the sample solution was used for measurement. A calibration curve was created using polystyrene as a standard substance.

[0173] <Film Thickness> The film thickness of the polyimide film samples obtained in each example was measured using a micrometer (MDC-25MX, manufactured by Mitutoyo Corporation). Five arbitrary points were measured, and the average value was taken as the film thickness.

[0174] <5% Mass Loss Temperature; Td5%> The polyimide film samples obtained in each example were measured using a differential thermomass analyzer (NEXTA STA200RV, Hitachi High-Tech Science Corporation). The polyimide film samples were heated from 40°C to 1,000°C at a heating rate of 10°C / min under a nitrogen atmosphere. The sample mass at the measurement temperature of 40°C was used as the reference, and the measurement temperature at which the mass decreased by 5% relative to this reference mass was defined as the 5% mass loss temperature (Td5%). If the 5% mass loss temperature is 500°C or higher, it indicates that "the 5% mass loss temperature is excellent and the heat resistance is excellent," and if it is less than 500°C, it indicates that "the 5% mass loss temperature is poor and the heat resistance is poor."

[0175] <Glass Transition Temperature; Tg> The polyimide film samples obtained in each example were placed in the container of a differential scanning calorimeter (DSC 204 F1 Phoenix, manufactured by NETZSCH). Then, under a nitrogen atmosphere, the samples were heated at a heating rate of 20°C / min to a temperature at least 30°C higher than the glass transition termination temperature, and a DSC curve was created. The glass transition temperature was defined as the temperature at the point where a line in the horizontal direction equidistant in the vertical direction from the extended lines of the high-temperature and low-temperature baselines in the horizontal direction of the DSC curve intersects with the curve of the step-like change portion of the glass transition. A glass transition temperature of 300°C or higher indicates "excellent glass transition temperature," and a temperature below 300°C indicates "inferior glass transition temperature."

[0176] <Linear Thermal Expansion Coefficient; CTE> The polyimide film samples obtained in each example were measured using a thermomechanical analyzer (TMA / SS7100, Hitachi High-Tech Science Corporation). Using a test piece (4 mm × 20 mm) of the polyimide film sample, the dimensional change was measured in the range of 100 to 200°C in tensile mode under a nitrogen atmosphere, with a heating rate of 5°C / min and a load of 10 mN. The dimensional change was defined as the difference between the maximum and minimum dimensions in the range of 100 to 200°C. The linear thermal expansion coefficient was calculated by dimensional change (ppm) / 100 (°C). A linear thermal expansion coefficient of 75 ppm / °C or less indicates "excellent linear thermal expansion coefficient," and a coefficient greater than 75 ppm / °C indicates "inferior linear thermal expansion coefficient."

[0177] (Synthesis of compound (1-E)) Compound (1-E) in the following formula (18) was synthesized according to the reaction pathway shown in formula (18).

[0178]

[0179] -Synthesis of compound (1-A)- 1,4-di(hydroxymethyl)benzene (15.0 g, manufactured by Tokyo Chemical Industries, Ltd.) and tetrahydrofuran (200 g, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were placed in a flask, triethylamine (44.2 g) was added, and the mixture was stirred. CF ３ CF ２ CF ２ OCF (CF ３ ) C=OF (72.5g) was added dropwise over 1 hour while maintaining the internal temperature below 15°C. After the dropwise addition was complete, the mixture was stirred at room temperature for 2 hours, and then the excess CF ３ CF ２ CF ２ OCF (CF ３ The C=OF was removed by vacuum distillation. After washing with water (100 mL), the mixture was washed three times with 0.1 N hydrochloric acid solution (50 mL) to remove any remaining triethylamine. The organic layer was then further processed using KHCO3. ３ The sample was washed three times with saturated aqueous solution (50 mL), dried over magnesium sulfate, filtered, and purified (77.6 g) was obtained by silica gel column chromatography (eluent: hexane / 1,1,2,2-tetrafluoro-1-(2,2,2-trifluoroethoxy)ethanol). １ H-NMR and１９ Analysis by F-NMR confirmed the formation of compound (1-A) described in formula (18), and the NMR yield was 93.7%. １９ F-NMR (376 MHz, solvent: CDCl ３ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): -80.1 to -79.6 (m, 2F), -81.6 to -81.5 (t, 6F), -82.2 to -82.1 (m, 6F), -87.1 to -86.6 (m, 2F), -130.0 (s, 4F), -132.0 to -131.9 (m, 2F). １ ¹H-NMR (400 MHz, solvent: CDCl) ３ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): 5.39 (s, 4H), 7.41 (s, 4H).

[0180] -Synthesis of Compound (1-B)- 250 g of CFE-419 was added to a 500 mL stainless steel SUS316L autoclave and stirred, and the temperature was maintained at 25°C. A cooler maintained at 20°C, a NaF pellet packed bed, and a cooler maintained at 0°C were installed in series at the autoclave gas outlet. A liquid return line was also installed to return the condensed liquid from the cooler maintained at 0°C back to the autoclave. Nitrogen gas was blown into the CFE-419 for 1 hour, and then fluorine gas diluted to 20% with nitrogen gas (hereinafter also referred to as "20% fluorine gas") was blown into the CFE-419 at a flow rate of 18.9 L / h for 1 hour. Next, while continuing to blow in 20% fluorine gas at the aforementioned flow rate, the entire raw material solution, which was a complete mixture of CFE-419 (270 g) and compound (1-A) (30 g) described in formula (18) as a raw material, was injected at a flow rate of 27.4 mL / h over 6.5 hours. Then, a CFE-419 solution (22.7 g) with a trifluorotoluene concentration of 0.99% by mass was injected over 0.5 hours, and 20% fluorine gas was continued to flow for another 0.5 hours. After that, nitrogen gas was blown in for 1 hour. The resulting crude solution was concentrated to obtain 40.16 g of liquid product. １９ Analysis by F-NMR confirmed the formation of compound (1-B) described in formula (18). Compound (1-B) was an isomer mixture with Cis:Trans = 41:59, and the NMR yield was 92%. １９F-NMR (376 MHz, solvent: CDCl ３ / C ６ F ６ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): -76.7 to -75.7 (m, 4F), -78.6 to -77.5 (m, 4F), -80.9 to -80.4 (m, 4F), -82.7 (m, 12F), -82.8 (m, 12F), -87.1 to -86.7 (m, 4F), -119.7 to -118.9 (m, 4F), -123.6 to -120.5 (m, 8F), -130.3 to -129.6 (m, 4F), -130.7 (m, 8F), -132.4 (m, 4F), -183.1 (m, 2F), -188.6 (m, 2F).

[0181] -Synthesis of compound (1-C)- Compound (1-B) (100 g) and KF (2.26 g) were placed in a flask equipped with a reaction distillation apparatus on top, and stirred at 100°C for 1.5 hours. After cooling to room temperature, a fraction (29.58 g) was obtained by vacuum distillation at an oil bath temperature of 60°C to 150°C. １９ Analysis using F-NMR confirmed the formation of compound (1-C) described in formula (18). Compound (1-C) was an isomer mixture with Cis:Trans = 41:59, and the NMR yield was 72%. １９ F-NMR (376 MHz, solvent: CDCl ３ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): 40.0 (m, 2F), 38.1 (m, 2F), -117.7 to -116.8 (m, 4F), -122.8 to -120.0 (m, 8F), -128.3 to -127.5 (m, 4F), -179.3 to -179.1 (m, 2F), -184.0 (m, 2F).

[0182] -Synthesis of compound (1-D)- Compound (1-C) (18.65 g) and lithium iodide (17.01 g) were placed in a round-bottom flask equipped with a reflux condenser at the top, and stirred under a nitrogen atmosphere at an oil bath temperature of 120°C for 2 hours. After cooling, the mixture was diluted with dichloromethane (30 mL) under a nitrogen atmosphere, solid components were removed by filter filtration, and the filtrate was collected in a round-bottom flask. After removing the dichloromethane by reducing the pressure of the filtrate, copper powder (8.08 g) was added, and the mixture was stirred at 140°C for 1 hour with a reflux condenser at the top. After cooling, the reactants other than the copper powder were dissolved in the dichloromethane, the copper powder was removed by filtration, and the mixture was concentrated to obtain the crude product. １９ Analysis using F-NMR confirmed the formation of the target product. The crude product was dissolved in hexane, and after liquid-liquid extraction with 10% by mass sodium bisulfite aqueous solution and saturated sodium bicarbonate aqueous solution, the purified product was obtained by silica gel column chromatography (eluent: hexane). １９ Analysis using F-NMR confirmed the formation of compound (1-D) described in formula (18). Compound (1-D) had a Cis:Trans ratio greater than 1:99, and 11.68 g was obtained (NMR yield 42%). １９ F-NMR (376 MHz, solvent: CDCl ３ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): -104.1 to -103.0 (m, 4F), -120.1 to -119.2 (m, 4F), -143.4 to -143.1 (m, 2F).

[0183] -Synthesis of compound (1-E)- 48 mL of t-butyl methyl ether and 94 mL of pure water were added to a three-necked flask equipped with a condenser at the top. Subsequently, 7.43 g of sodium bicarbonate, 3.17 g of tetrabutylammonium bisulfate, 6.70 g of aniline, and Na were added. ２ S ２ O ４ (15.40 g) and compound (1-D) (18.18 g) were added as starting materials, and the mixture was stirred at room temperature for 18 hours. 20 mL of t-butyl methyl ether and 40 mL of THF were added to the reaction mixture and stirred to dissolve the precipitate. The organic layer was then washed with saturated sodium bicarbonate aqueous solution and brine (saturated saline solution). The organic layer was concentrated to obtain the crude product.１９ Analysis by F-NMR confirmed the formation of the target product. The crude product was washed with a large amount of 1,1,2,2-Tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane by stirring, and the solid was filtered off. The obtained solid was recrystallized in a mixed solvent of acetonitrile and 1,1,2,2-Tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane (volume ratio 5:4) to obtain the purified product. １９ F-NMR and １ Analysis using 1H-NMR confirmed the formation of compound (1-E) described in formula (18). Compound (1-E) had a Cis:Trans ratio greater than 1:99, and 6.15 g (NMR yield 34%) was obtained. １９ F-NMR (376MHz, solvent: THF-d ８ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): -117.7 to -116.9 (m, 4F), -131.5 to -130.8 (m, 4F), -179.2 to -179.0 (m, 2F). １ ¹H-NMR (400 MHz, solvent: THF-d) ８ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): 5.08 (s, 4H), 6.71-6.73 (d, 4H), 7.41-7.43 (d, 4H).

[0184] (Synthesis of compound (2-E)) Compounds (2-B), (2-C), (2-D), and (2-E) in formula (19) below were synthesized according to the reaction pathway in formula (19), which is similar to the reaction pathway in formula (18), except that compound (2-A) in formula (19) was used instead of compound (1-A).

[0185]

[0186] -Synthesis of compound (2-A)- Except for using 1,3-di(hydroxymethyl)benzene (15 g, manufactured by Tokyo Chemical Industry Co., Ltd.) instead of 1,4-di(hydroxymethyl)benzene as a starting material, 76.1 g of the product was obtained by following the synthesis method of compound (1-A). １ H-NMR and １９Analysis by F-NMR confirmed the formation of compound (2-A) described in formula (19), and the NMR yield was 91.9%. １９ F-NMR (376 MHz, solvent: CDCl ３ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): -80.2 to -79.7 (m, 2F), -81.6 to -81.5 (t, 6F), -82.2 to -82.1 (m, 6F), -87.0 to -86.6 (m, 2F), -130.0 (s, 4F), -132.0 to -131.9 (m, 2F). １ ¹H-NMR (400 MHz, solvent: THF-d) ８ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): 5.39 (s, 4H), 7.39-7.47 (m, 4H).

[0187] -Synthesis of compound (2-B)- Except for using compound (2-A) (38 g) instead of compound (1-A) as a starting material, the synthesis method was followed to obtain 48.86 g of the product. １９ Analysis by F-NMR confirmed the formation of compound (2-B), which was an isomer mixture with a Cis:Trans ratio of 51:49, and the NMR yield was 89%. １９ F-NMR (376 MHz, solvent: CDCl ３ / C ６ F ６ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): -77.6 to -74.6 (m, 8F), -80.9 to -79.7 (m, 4F), -81.9 to -81.8 (m, 12F), -82.0 (m, 12F), -86.6 to -86.1 (m, 4F), -114.4 to -114.2 (m, 2F), -115.5 to -114.6 (m, 1F), -119.1 to -117.7 (m, 3F), -121.0 to -120.2 (m, 2F), -122.1 to -121.1 (m, 1F), -125.7 to -125.1 (m, 2F), -127.6 to -126.4 (m, 2F), -130.0 (m, 8F), -130.9 (m, 2F), -131.8 to -131.7 (m, 4F), -140.1 to -139.1 (m, 1F), -181.6 to -181.5 (m, 2F), -186.2 (m, 2F).

[0188] -Synthesis of compound (2-C)- Except for using compound (2-B) (88g) instead of compound (1-B) as a starting material, the synthesis method for compound (1-C) was followed, and a fraction of 18.99g was obtained. １９ Analysis by F-NMR confirmed the formation of compound (2-C), which was an isomer mixture with a Cis:Trans ratio of 51:49, and the NMR yield was 62%. １９ F-NMR (376 MHz, solvent: CDCl ３ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): 39.6–39.7 (m, 2F), 38.0–38.1 (m, 2F), -112.8–-111.8 (m, 1F), -114.5–-114.4 (m, 2F), -119.1–-117.4 (m, 3F), -122.1–-121.1 (m, 1F), -124.4–-122.4 (m, 4F), -129.2 (m, 2F), -131.2–-130.3 (m, 2F), -139.7–-138.8 (dq, 1F), -179.1–-178.7 (m, 2F), -182.2 (s, 2F).

[0189] -Synthesis of compound (2-D)- The purified product was obtained by following the synthesis method of compound (1-D), except that compound (2-C) (21.09 g) was used instead of compound (1-C). １９ Analysis using F-NMR confirmed the formation of compound (2-D). Compound (2-D) had a Cis:Trans ratio of ≥99:1, and 6.62 g (NMR yield 22%) was obtained. １９ F-NMR (376 MHz, solvent: CDCl ３ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): -87.5 to -86.5 (m, 1F), -105.1 to -104.3 (m, 2F), -108.7 to -107.9 (dt, 1F), -121.2 to -120.3 (m, 1F), -126.4 to -125.7 (m, 2F), -132.5 to -131.6 (dq, 1F), -142.3 to -141.9 (m, 2F).

[0190] -Synthesis of compound (2-E)- The purified product was obtained by following the synthesis method of compound (1-E), except that compound (2-D) (0.2986 g) was used instead of compound (1-D) as a raw material. １９ F-NMR and １ Analysis using 1H-NMR confirmed the formation of compound (2-E). Compound (2-E) had a Cis:Trans ratio of ≥99:1, and 0.066 g (NMR yield 25%) was obtained. １９ F-NMR (376 MHz, solvent: CDCl ３ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): -114.4 to -113.4 (m, 1F), -119.4 to -118.5 (m, 2F), -122.2 to -121.2 (m, 1F), -125.4 to -124.4 (m, 1F), -134.7 to -133.8 (m, 2F), -138.5 to -137.6 (m, 1F), -178.8 to -178.7 (m, 2F). １ ¹H-NMR (400 MHz, solvent: CDCl) ３ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): 3.88 (s, 4H), 6.70-6.74 (m, 4H), 7.46-7.48 (m, 4H).

[0191] (Synthesis of compound (3-E)) Compounds (3-B), (3-C), (3-D), and (3-E) in formula (20) below were synthesized using compound (3-A) in formula (20) instead of compound (1-A). All other compounds were synthesized according to the reaction pathway in formula (20), which is similar to the reaction pathway in formula (18).

[0192]

[0193] -Synthesis of compound (3-A)- Except for using 4,4'-bis(hydroxymethyl)biphenyl (15.0 g, manufactured by Tokyo Chemical Industry Co., Ltd.) instead of 1,4-di(hydroxymethyl)benzene as a starting material, 55.6 g of the product was obtained by following the synthesis method of compound (1-A). １ H-NMR and １９ Analysis by F-NMR confirmed the formation of compound (3-A) described in formula (20), and the NMR yield was 94.8%. １９F-NMR (376 MHz, solvent: CDCl ３ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): -80.1 to -79.6 (m, 2F), -81.5 to -81.4 (t, 6F), -82.2 to -82.1 (m, 6F), -86.9 to -86.4 (m, 2F), -129.9 (s, 4F), -131.9 to -131.8 (m, 2F). １ ¹H-NMR (400 MHz, solvent: CDCl) ３ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): 5.40–5.46 (m, 4H), 7.44–7.47 (m, 4H), 7.61–7.64 (m, 4H).

[0194] -Synthesis of compound (3-B)- Except for using compound (3-A) (20 g) instead of compound (1-A) as a starting material, the synthesis method was followed to obtain 32.66 g of the product. １９ Analysis by F-NMR confirmed the formation of compound (3-B), which is an isomer mixture, and the NMR yield was 83%. １９ F-NMR (376 MHz, solvent: CDCl ３ / C ６ F ６ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): -77.5 to -74.9 (m, 4F), -79.9 to -79.5 (m, 2F), -81.7 to -81.6 (t, 6F), -81.8 (s, 6F), -86.2 to -85.8 (m, 2F), -128.0 to -114.6 (m, 16F), -129.7 (s, 4F), -131.4 to -130.5 (d, 2F), -187.6 to -174.6 (m, 4F).

[0195] -Synthesis of compound (3-C)- Except for using compound (3-B) (54 g) instead of compound (1-B) as a starting material, the synthesis method for compound (1-C) was followed, and a fraction of 22.3 g was obtained. １９ Analysis using F-NMR confirmed the formation of compound (3-C). It was an isomer mixture, and the NMR yield was 85%. １９ F-NMR (376 MHz, solvent: CDCl ３ , Internal standard substance: C ６ F６ ) δ (ppm): 36.8 to 40.0 (2F), -127.0 to -114.6 (16F), -187.3 to -178.9 (4F).

[0196] -Synthesis of compound (3-D)- The purified product was obtained by following the synthesis method of compound (1-D), except that compound (3-C) (2.0 g) was used instead of compound (1-C) as a raw material. １９ Analysis using F-NMR confirmed the formation of compound (3-D). Compound (3-D) had a trans-trans:trans-cis:cis-cis ≥ 99:1:1 ratio, and 0.488 g (NMR yield 20%) was obtained. １９ F-NMR (376 MHz, solvent: CDCl ３ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): -103.6 to -102.6 (m, 4F), -116.3 to -115.5 (m, 4F), -121.2 to -120.4 (m, 4F), -122.4 to -121.6 (m, 4F), -145.0 to -144.6 (m, 2F), -179.5 to -179.1 (m, 2F).

[0197] -Synthesis of compound (3-E)- The purified product was obtained by following the synthesis method of compound (1-E), except that compound (3-D) (0.3602 g) was used instead of compound (1-D) as a raw material. １９ F-NMR and １ Analysis using 1H-NMR confirmed the formation of compound (3-E). Compound (3-E) had a trans-trans:trans-cis:cis-cis ≥ 99:1:1 ratio, and 0.041 g (NMR yield 12%) was obtained. １９ F-NMR (376MHz, solvent: THF-d ８ (Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): -116.9 to -115.6 (m, 8F), -124.4 to -123.6 (m, 4F), -130.7 to -129.9 (m, 4F), -179.2 to -178.8 (m, 4F). １ ¹H-NMR (400 MHz, solvent: THF-d) ８(Internal standard substance: 1,4-bistrifluoromethylbenzene) δ (ppm): 5.15 (s, 4H), 6.66-6.70 (m, 4H), 7.33-7.35 (m, 4H).

[0198] <Preparation of Polyimide Film Samples> (Example 1) Under a nitrogen atmosphere, 6 FDA (888.4 mg, 2.0 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), compound (1-E) (803.3 mg, 1.8 mmol), TFMB (64.2 mg, 0.2 mmol), dehydrated THF (0.4 g), and dehydrated DMF (15.5 g) were added to a 50 mL two-necked flask equipped with a stirring bar, and a polyamic acid solution was prepared by stirring at room temperature for 24 hours. 6.5 mL of an anhydride acetic acid / pyridine mixture (volume ratio 7 / 3) was added to the reaction solution and the mixture was stirred at room temperature for 20 hours to carry out chemical imidation. The reaction solution was dropped dropwise into a large amount of methanol to precipitate and filter the polyimide. After thorough washing with methanol, polyimide powder was obtained by vacuum drying at 100°C (1.76 g, 93.2%). The weight-average molecular weight of the obtained polyimide was 205,900. To form a film, cyclopentanone was added to the polyimide powder to obtain a solution varnish (the polyimide powder content relative to the total mass of the solution was 10% by mass). The obtained varnish was applied to a silicon wafer and dried under a nitrogen atmosphere at 60°C for 2 hours to convert the applied solution into a polyimide film. The polyimide film was peeled from the silicon wafer and further vacuum-dried at 100°C for 15 minutes, 150°C for 30 minutes, 200°C for 30 minutes, and 280°C for 1 hour to obtain a polyimide film sample with a thickness of approximately 27 μm. The Td 5% of the polyimide film sample was 526°C, Tg was 323°C, and CTE was 51 ppm / °C.

[0199] (Example 2) Under a nitrogen atmosphere, 6FDA (888.7 mg, 2.0 mmol), compound (1-E) (669.7 mg, 1.5 mmol), TFMB (160.1 mg, 0.5 mmol), dehydrated THF (0.6 g), and dehydrated DMF (14.9 g) were added to a 50 mL two-necked flask equipped with a stirring bar, and the mixture was stirred at room temperature for 24 hours to prepare a polyamic acid solution. 6.5 mL of an anhydride acetic acid / pyridine mixture (volume ratio 7 / 3) was added to the reaction solution and the mixture was stirred at room temperature for 20 hours to carry out chemical imidation. The reaction solution was added dropwise to a large amount of methanol to precipitate the polyimide, and the solution was filtered. After thorough washing with methanol, the polyimide powder was obtained by vacuum drying at 100°C (1.60 g, 93.2%). The weight-average molecular weight of the obtained polyimide was 391,800. To form a film, cyclopentanone was added to the polyimide powder to obtain a solution varnish (the polyimide powder content relative to the total mass of the solution was 10% by mass). The obtained varnish was applied to a silicon wafer and dried under a nitrogen atmosphere at 60°C for 2 hours to convert the applied solution into a polyimide film. The polyimide film was peeled from the silicon wafer and further vacuum-dried at 100°C for 15 minutes, 150°C for 30 minutes, 200°C for 30 minutes, and 280°C for 1 hour to obtain a polyimide film sample with a thickness of approximately 30 μm. The Td 5% of the polyimide film sample was 530°C, Tg was 321°C, and CTE was 53 ppm / °C.

[0200] (Example 3) Under a nitrogen atmosphere, 6FDA (1.33 g, 3.0 mmol), compound (1-E) (0.67 g, 1.5 mmol), TFMB (0.48 g, 1.5 mmol), dehydrated THF (0.6 g), and dehydrated DMF (21.6 g) were added to a 50 mL two-necked flask equipped with a stirring bar, and the mixture was stirred at room temperature for 24 hours to prepare a polyamic acid solution. 9.8 mL of an acetic anhydride / pyridine mixture (volume ratio 7 / 3) was added to the reaction solution and the mixture was stirred at room temperature for 20 hours to carry out chemical imidation. The reaction solution was added dropwise to a large amount of methanol to precipitate the polyimide, and it was filtered. After thorough washing with methanol, polyimide powder was obtained by vacuum drying at 100°C (2.27 g, 91.5%). The weight-average molecular weight of the obtained polyimide was 296,100. To form a film, cyclopentanone was added to the polyimide powder to obtain a solution varnish (the polyimide powder content relative to the total mass of the solution was 10% by mass). The obtained varnish was applied to a silicon wafer and dried under a nitrogen atmosphere at 60°C for 2 hours to convert the applied solution into a polyimide film. The polyimide film was peeled from the silicon wafer and further vacuum-dried at 100°C for 15 minutes, 150°C for 30 minutes, 200°C for 30 minutes, and 280°C for 1 hour to obtain a polyimide film sample with a thickness of approximately 26 μm. The Td 5% of the polyimide film sample was 530°C, Tg was 324°C, and CTE was 56 ppm / °C.

[0201] (Example 4) Under a nitrogen atmosphere, 6FDA (1.33 g, 3.0 mmol), compound (1-E) (1.34 g, 3.0 mmol), and dehydrated DMF (8.5 g) were added to a 50 mL two-necked flask equipped with a stirring bar, and the mixture was stirred at room temperature for 24 hours to prepare a polyamic acid solution. To perform film formation and thermal imidation, the varnish was applied to a silicon wafer and dried under a nitrogen atmosphere at 60°C for 2 hours to convert the applied solution into a polyamic acid film. The polyamic acid film was peeled from the silicon wafer, and the polyamic acid film was further heated under a nitrogen atmosphere at 80°C for 10 minutes, increasing the temperature from 80°C to 350°C at a rate of 3°C / min, and then thermal imidized at 350°C for 1 hour and 30 minutes to obtain a polyimide film sample with a thickness of approximately 75 μm. The Td 5% of the polyimide film sample was 513°C, Tg was 323°C, and CTE was 73 ppm / °C.

[0202] (Example 5) Under a nitrogen atmosphere, 6FDA (444.3 mg, 1.0 mmol), compound (1-E) (223.1 mg, 0.5 mmol), TFMB (160.1 mg, 0.5 mmol), dehydrated THF (0.2 g), and dehydrated DMF (4.5 g) were added to a 50 mL two-necked flask equipped with a stirring bar, and the mixture was stirred at room temperature for 24 hours to prepare a polyamic acid solution varnish. To perform film formation and thermal imidation, the varnish was applied to a silicon wafer and dried under a nitrogen atmosphere at 60°C for 2 hours to convert the applied solution into a polyamic acid film. The polyamic acid film was peeled from the silicon wafer, and the polyamic acid film was further heated under a nitrogen atmosphere at 80°C for 10 minutes, then heated from 80°C to 350°C at a rate of 3°C / min, and thermal imidized at 350°C for 1 hour and 30 minutes to obtain a polyimide film sample with a thickness of approximately 35 μm. The Td of the polyimide film sample at 5% was 526°C, Tg was 322°C, and CTE was 60 ppm / °C.

[0203] (Example 6) Under a nitrogen atmosphere, 6FDA (444.5 mg, 1.0 mmol), compound (2-E) (223.0 mg, 0.5 mmol), TFMB (159.9 mg, 0.5 mmol), dehydrated THF (0.2 g), and dehydrated DMF (4.5 g) were added to a 50 mL two-necked flask equipped with a stirring bar, and the mixture was stirred at room temperature for 24 hours to prepare a polyamic acid solution varnish. To perform film formation and thermal imidation, the varnish was applied to a silicon wafer and dried under a nitrogen atmosphere at 60°C for 2 hours to convert the applied solution into a polyamic acid film. The polyamic acid film was peeled from the silicon wafer, and the polyamic acid film was further heated under a nitrogen atmosphere at 80°C for 10 minutes, then heated from 80°C to 350°C at a rate of 3°C / min, and thermal imidized at 350°C for 1 hour and 30 minutes to obtain a polyimide film sample with a thickness of approximately 45 μm. The Td 5% of the polyimide film sample was 531°C, Tg was 323°C, and CTE was 54 ppm / °C.

[0204] (Example 7) Under a nitrogen atmosphere, 6FDA (1.33 g, 3.0 mmol), compound (1-E) (0.33 g, 0.75 mmol), TFMB (0.72 g, 2.25 mmol), dehydrated THF (0.6 g), and dehydrated DMF (22.6 g) were added to a 50 mL two-necked flask equipped with a stirring bar, and the mixture was stirred at room temperature for 24 hours to prepare a polyamic acid solution. 9.8 mL of an anhydride acetic acid / pyridine mixture (volume ratio 7 / 3) was added to the reaction solution and the mixture was stirred at room temperature for 20 hours to carry out chemical imidation. The reaction solution was added dropwise to a large amount of methanol to precipitate the polyimide, and the solution was filtered. After thorough washing with methanol, the polyimide powder was obtained by vacuum drying at 100°C (2.27 g, 95.4%). The weight-average molecular weight of the obtained polyimide was 467,900. To form a film, cyclopentanone was added to the polyimide powder to obtain a solution varnish (the polyimide powder content relative to the total mass of the solution was 10% by mass). The obtained varnish was applied to a silicon wafer and dried under a nitrogen atmosphere at 60°C for 2 hours to convert the applied solution into a polyimide film. The polyimide film was peeled from the silicon wafer and further vacuum-dried at 100°C for 15 minutes, 150°C for 30 minutes, 200°C for 30 minutes, and 280°C for 1 hour to obtain a polyimide film sample with a thickness of approximately 31 μm. The Td 5% of the polyimide film sample was 529°C, Tg was 322°C, and CTE was 56 ppm / °C.

[0205] (Example 8) Under a nitrogen atmosphere, 6FDA (1.33 g, 3 mmol), 12FHDA (1.45 g, 3.0 mmol), and dehydrated N-methylpyrrolidone (13.3 g) were added to a 50 mL two-necked flask equipped with a stirring bar, and the mixture was stirred at room temperature for 24 hours to prepare a polyamic acid solution. 9.8 mL of an acetic anhydride / pyridine mixture (volume ratio 7 / 3) was added to the reaction solution and the mixture was stirred at room temperature for 20 hours to carry out chemical imidation. The reaction solution was added dropwise to a large amount of methanol to precipitate the polyimide, and the solution was filtered. After thorough washing with methanol, the solution was vacuum-dried at 100°C to obtain polyimide powder (2.60 g, 93.2%). The weight-average molecular weight of the obtained polyimide was 497,000. To form a film, cyclopentanone was added to the polyimide powder to obtain a solution varnish (the polyimide powder content relative to the total mass of the solution was 20% by mass). The obtained varnish was applied to a silicon wafer and dried under a nitrogen atmosphere at 60°C for 2 hours to convert the applied solution into a polyimide film. The polyimide film was peeled from the silicon wafer and further vacuum-dried at 100°C for 15 minutes, 150°C for 30 minutes, 200°C for 30 minutes, and 280°C for 1 hour to obtain a polyimide film sample with a thickness of approximately 60 μm. The Td 5% of the polyimide film sample was 532°C, Tg was 223°C, and CTE was 92 ppm / °C.

[0206]

[0207] In Examples 1 to 7, which used polyimide film samples obtained from polyimides having a repeating structure represented by formula (9), the Tg was 300°C or higher, indicating excellent Tg and heat resistance. Furthermore, in Examples 1 to 7, the CTE at 100 to 200°C was 75 ppm / °C or less, indicating excellent CTE and dimensional stability. On the other hand, in Example 8, which used polyimide film samples obtained from polyimides without the repeating structure represented by formula (9), the Tg was less than 300°C, indicating poor Tg and heat resistance. This is because the rigid skeleton derived from the polyfluorocyclohexylene group cannot be introduced into the polyimide, making it difficult for the polyimide molecules to arrange themselves regularly. As a result, the molecules do not require much thermal energy to move freely, which is thought to be the reason why the glass transition temperature is low. Furthermore, in Example 8, the CTE was greater than 75 ppm / °C, indicating poor CTE and dimensional stability. This is thought to be because the motion of the molecules could not be suppressed, the dimensions of the molecules were easily changed by thermal changes, and the coefficient of thermal expansion became high.

Claims

A compound represented by the following formula (1). In formula (1) above, n1 and n2 represent the number of fluorine atoms, each being an integer between 6 and 10, the sum of the numbers n1 and n2 being between 6 and 20, and t1 being 0 or 1. 　 A compound represented by the following formula (2). In the above formula (2), n3 and n4 represent the number of fluorine atoms, each being an integer from 6 to 10 independently, the sum of the numbers of n3 and n4 being from 6 to 20, t2 being 0 or 1, Y １ and Y ２ Each of these is independently an alkylene group having or having no substituents, a divalent group in which at least one carbon atom not bonded to the nitrogen atom of the alkylene group is substituted with a heteroatom, a carbonate group, a carbamate group, a urea group, an amide group, an ester group, a thiocarbonate group, a thiocarbamate group, a thioamide group, or a thiourea group, or an arylene group having or having no substituents. 　 The aforementioned Y １ This is an arylene group represented by the following formula (3), and the Y ２ The compound according to claim 2, wherein is an arylene group represented by the following formula (4). In the above formulas (3) and (4), the substituent R １ and R ２ each independently represent a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or an aryl group having 6 to 9 carbon atoms, m1 represents the number of R １ , m2 represents the number of R ２ , each is independently an integer of 0 to 4, * ＮＨ２ is a bond to an amino group, * １ and * ２ are bonds to a polyfluorocyclohexylene group. When m1 is 2 or more, a plurality of R １ may be the same or different. If m2 is 2 or more, multiple R ２ They are either the same or different. 　 A polyamic acid having a repeating structure represented by the following formula (5). In the above formula (5), n5 and n6 represent the number of fluorine atoms, each being an integer from 6 to 10 independently, the sum of the numbers of n5 and n6 being from 6 to 20, t3 being 0 or 1, Y ３ and Y ４ Each of these is an alkylene group having or having no substituents, a divalent group in which at least one carbon atom not bonded to the nitrogen atom of the alkylene group is substituted with a heteroatom, carbonate group, carbamate group, urea group, amide group, ester group, thiocarbonate group, thiocarbamate group, thioamide group, or thiourea group, or an arylene group having or having no substituents, X １ It is a tetravalent organic group. The aforementioned Y ３ This is an arylene group represented by the following formula (6), and the Y ４ The polyamic acid according to claim 4, wherein is an arylene group represented by the following formula (7). In formulas (6) and (7) above, substituent R ３ and R ４ Each of these independently represents a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a C1-C4 alkyl group, a C1-C4 alkoxy group, or a C6-C9 aryl group, and m3 is R ３ It represents the number of, and m4 is R ４ The numbers are represented, and each is an independent integer from 0 to 4, * Ｎ This is a bond with the nitrogen atom, * ３ and * ４ This is a bond with a polyfluorocyclohexylene group, * ５ This is a coupling. If m3 is 2 or more, multiple R ３ They are either the same or different. If m4 is 2 or more, multiple R ４ They are either the same or different. The aforementioned X １ The polyamic acid according to claim 4, wherein the polyamic acid is represented by the following formula (8). In equation (8) above, * represents a coupling. 　 A polyimide having a repeating structure represented by the following formula (9). In the above formula (9), n7 and n8 represent the number of fluorine atoms, each being an integer from 6 to 10 independently, the sum of the numbers of n7 and n8 being from 6 to 20, t4 being 0 or 1, Y ５ and Y ６ Each of these is an alkylene group having or having no substituents, a divalent group in which at least one carbon atom not bonded to the nitrogen atom of the alkylene group is substituted with a heteroatom, carbonate group, carbamate group, urea group, amide group, ester group, thiocarbonate group, thiocarbamate group, thioamide group, or thiourea group, or an arylene group having or having no substituents, X ２ It is a tetravalent organic group. The aforementioned Y ５ This is an arylene group represented by the following formula (10), and the Y ６ The polyimide according to claim 7, wherein is an arylene group represented by the following formula (11). In formulas (10) and (11) above, substituent R ５ and R ６ Each of these independently represents a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a C1-C4 alkyl group, a C1-C4 alkoxy group, or a C6-C9 aryl group, and m5 is R ５ It represents the number of, and m6 is R ６ The numbers are represented, and each is an independent integer from 0 to 4, * Ｎ This is a bond with the nitrogen atom, * ６ and * ７ This is a bond with a polyfluorocyclohexylene group, * ８ This is a coupling. If m5 is 2 or more, multiple R ５ They are either the same or different. If m6 is 2 or more, multiple R ６ They are either the same or different. The aforementioned X ２ The polyimide according to claim 7, wherein the coefficient is represented by the following formula (12). In equation (12) above, * represents a coupling. 　 A varnish comprising a polyamic acid or polyimide according to any one of claims 4 to 9. 　 A film obtained from the varnish described in claim 10.

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