Polyimide precursor, polyimide precursor composition, polyimide, polyimide molded article and method for producing the same, and acid anhydride compound

Abstract

To provide a polyimide precursor capable of forming a molded article exhibiting a low dielectric loss tangent.SOLUTION: A polyimide precursor includes a structural unit represented by formula (I), and at least one of X1 or X2 includes a dicyclopentadienyl group represented by formula (10).SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a polyimide precursor, a polyimide precursor composition, a polyimide, a polyimide molded article and a method for producing the same, and an acid anhydride compound.

Background Art

[0002] Polyimide films are widely applied in various electronic components as protective films for protecting wirings or members such as substrates. A polyimide film can be formed by heating a resin film containing a polyimide precursor having an amide group derived from an acid anhydride (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure relates to a polyimide precursor capable of forming a molded article exhibiting a low dielectric tangent.

Means for Solving the Problems

[0005] The present disclosure includes the following. [1] The following formula (I):

Chemical Formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[10] The polyimide molded article according to [9], which is a polyimide film. 「11」 The following formula (21):

Chemical formula

[16] The following formula (22):

Chemical formula

Advantages of the Invention

[0006] A polyimide precursor capable of forming a molded article having a low dielectric tangent can be provided. The molded article formed from the polyimide precursor may also have excellent heat resistance.

Modes for Carrying Out the Invention

[0007] The present invention is not limited to the following examples.

[0008] An example of the polyimide precursor is represented by the following formula (I):

Chemical formula

Chemical formula

Chemical formula

[0009] The polyimide precursor can be a polymer having a polymer chain composed of a plurality of continuously bonded structural units including the structural unit represented by formula (I). The polymer chain of the polyimide precursor may include structural units other than the structural unit represented by formula (I). The proportion of the structural unit represented by formula (I) in the polyimide precursor may be 30% by mass or more, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 95% by mass or more based on the mass of the polyimide precursor, and may be 100% by mass or less.

[0010] X 1When it contains a dicyclopentadienyl group, X 1 is an organic group which may contain a group represented by the following formula (II): [Chemical formula] In formula (II), * represents a bond, X 3 represents a trivalent organic group containing two adjacent carbon atoms, L represents a direct bond or a divalent linker group, Ar 1 represents a divalent aromatic group which may have a substituent, Ar 2 represents a trivalent aromatic group which may have a substituent, and n represents an integer of 0 or more. A plurality of X 3 , L, Ar 1 and Ar 2 may be the same or different from each other. The two bonds * bonded to one X 3 are respectively bonded to two adjacent carbon atoms in X 3 , and two sets of the combinations of the two bonds * bonded to one X 3 are the four bonds of X 1 in formula (I). When n is 1 or more, that is, when there are three or more combinations of the two bonds * bonded to one X 3 , the structure to which the bonds * other than the four bonds of X 1 in formula (I) are bonded is arbitrary. The bonds * other than the four bonds of X 1 in formula (I) may be bonded to an amide group or an ester group similar to the amide group or the ester group in formula (I), thereby forming a branched polymer chain.

[0011] X 3 may be an alicyclic group (e.g., cyclohexane ring) which may have a substituent, or an aromatic group (e.g., benzene ring) which may have a substituent. The substituent which the alicyclic group or the aromatic group as X 3 has may be an alkyl group having 1 to 5 carbon atoms (e.g., methyl group) or an alkenyl group having 1 to 5 carbon atoms (e.g., allyl group). X 3 may be a residue of a tricarboxylic anhydride. X 3Examples of tricarboxylic anhydrides that induce [it] include cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, trimellitic anhydride, octahydro-4-methyl-1,3-dioxo-5-isobenzofurancarboxylic acid (cas:185855-13-4), and 1,3-dihydro-4-methyl-1,3-dioxo-5-isobenzofurancarboxylic acid (cas:185855-21-4).

[0012] L may be a direct bond or may be a linker group selected from a carboxylic acid ester group (-C(=O)O-) and a carboxylic acid amide group (-C(=O)NH-).

[0013] Ar 1 and Ar 2 are aromatic groups that may have substituents, and may be, for example, a phenylene group or a biphenylene group. Ar 1 or Ar 2 The substituents that the aromatic group as may have are an alkyl group having 1 to 5 carbon atoms (for example, a methyl group) or an alkenyl group having 1 to 5 carbon atoms (for example, an allyl group).

[0014] Specific examples of the group represented by formula (II) include groups represented by the following formula (IIa) or (IIb). In formula (IIa) or (IIb), * indicates the same bond as * in formula (II). R 3 and R 4 each independently represent an alkyl group having 1 to 5 carbon atoms (for example, a methyl group) or an alkenyl group having 1 to 5 carbon atoms, p represents an integer from 0 to 4, q represents an integer from 0 to 3, and n represents an integer of 0 or more. p may be 0 or 1. q may be 0. n may be 10 or less.

Chemical formula

Chemical formula

[0015] X containing a dicyclopentadienediyl group1 may also be a group represented by the following formula (III).

Chemical formula

[0016] In formula (III), * represents a bond, and L and X 3 are the same as L and X in formula (II) 3 and are defined in the same way, R 5 represents a divalent organic group (for example, a linear, branched or cyclic saturated aliphatic group which may have a substituent, or an aromatic group which may have a substituent), and X 4 represents an aromatic group which may have a substituent (such as a phenylene group, a biphenylene group, etc.), an alicyclic group which may have a substituent (such as a cyclohexanediyl group, etc.), or a group containing an aromatic group which may have a substituent and an alkanediyl group having 1 to 3 carbon atoms for bonding them. The substituent which the aromatic group or alicyclic group contained in X 4 may have may be, for example, an alkyl group having 1 to 5 carbon atoms (such as a methyl group, etc.) or an alkenyl group having 1 to 5 carbon atoms (such as an allyl group, etc.).

[0017] Specific examples of the group represented by formula (III) include the group represented by the following formula (IIIa). R and n in formula (IIIa) 5 are defined in the same way as R and n in formula (II). R 5 is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms (such as a methyl group, etc.), or an alkenyl group having 1 to 5 carbon atoms (such as an allyl group, etc.). 6 In formula (I), when X

Chemical formula

[0018] contains a dicyclopentadienediyl group, X 2 may be a tetravalent organic group not containing a dicyclopentadienediyl group. X not containing a dicyclopentadienediyl group 1 1 ​may be a group containing an alicyclic group other than a dicyclopentadienediyl group which may have a substituent, an aromatic group which may have a substituent, or a C1-C3 alkanediyl group which may have a substituent and which binds two or more aromatic groups which may have a substituent. X which does not contain a dicyclopentadienediyl group 1 can be a residue derived from any tetracarboxylic dianhydride. X which does not contain a dicyclopentadienediyl group 1 Examples of tetracarboxylic dianhydrides from which 1 is derived include pyromellitic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 2-methyl-1,4-phenylenebis(trimeritate anhydride), p-phenylenebis(trimeritate anhydride), 4,4'-oxydiphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic acid, bis(1,3'-dioxo-1,3'-dihydroisobenzofuran-5-carboxylic acid)=1,1'-biphenyl-4,4'-diyl, 2,2',3,3',5,5'-hexamethyl-[1,1'-biphenyl]-4,4'-diylbis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, and 2,2-bis(4-hydroxyphenyl)propanedibenzoate-3,3',4,4'-tetracarboxylic dianhydride.

[0019] X 2 When X contains a dicyclopentadienediyl group, X 2 can be a residue of any diamine compound containing a dicyclopentadienediyl group. Examples of diamine compounds containing a dicyclopentadienediyl group include octahydro-4,7-methano-1H-inden-1,5-dimethanamine, octahydro-4,7-methano-1H-inden-2,5-dimethanamine, octahydro-4,7-methano-1H-inden-1,6-dimethanamine, octahydro-4,7-methano-1H-inden-1,2-dimethanamine, and octahydro-4,7-methano-1H-inden-1,1-dimethanamine.

[0020] In formula (I), X1 When it contains a dicyclopentadienediyl group, X 2 may be a divalent organic group that does not contain a dicyclopentadienediyl group. X that does not contain a dicyclopentadienediyl group 2 may be an alicyclic group other than a dicyclopentadienediyl group which may have a substituent, an aromatic group which may have a substituent, two or more aromatic groups or alicyclic groups which may have a substituent and a divalent group (e.g., an alkanediyl group having 1 to 3 carbon atoms, an oxy group, a sulfonyl group, or a thio group) bonding them, an alkanediyl group which may have a substituent, a polyoxyalkylene group, or a siloxane group. X that does not contain a dicyclopentadienediyl group 2 can be a residue derived from any diamine compound. X that does not contain a dicyclopentadienediyl group 2Examples of diamine compounds that induce are 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl methane, 4,4'-methylenebis(cyclohexylamine), 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl methane, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 1,4-bis(4-aminophenoxy)benzene, m-phenylenediamine, p-phenylenediamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine, bis(4-aminophenoxyphenyl) sulfone, bis(3-aminophenoxyphenyl) sulfone, bis(4-aminophenoxy)biphenyl, bis{4-(4-aminophenoxy)phenyl} ether, 1,4-bis(4-aminophenoxy)benzene, benzidine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-diethyl-4,4'-diaminobiphenyl, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-diethyl-4,4'-diaminobiphenyl, 3,3'-ditrifluoromethyl-4,4'-diaminobiphenyl, 2,2',3,3'-tetramethyl-4,4'-diaminobiphenyl, 3,3',4,4'-tetramethyl-4,4'-diaminobiphenyl, bis(3-amino-4-hydroxyphenyl) sulfone, bis(3-amino-4-hydroxyphenyl) propane, bis(3-amino-4-hydroxyphenyl) methylene, bis(3-amino-4-hydroxyphenyl) ether, bis(3-amino-4-hydroxy)biphenyl, bis(3-amino-4-hydroxyphenyl) fluorene, bis(3-aminopropyl)tetramethyldisiloxane, bis(p-amino-phenyl)octamethylpentasiloxane, ethylenediamine, 1,3-diaminopropane, 2-methyl-1,3-propanediamine, 1,4-diaminobutane, 1,5-diaminopentane, 2-methyl-1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,It contains 1,2-diaminododecane and 1,2-bis(2-aminoethoxy)ethane.,

[0021] R in formula (I) 1 and R 2 is a hydrogen atom or a monovalent organic group. R 1 and R 2 may each independently be a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent, or an alkylsilyl group having 3 to 9 carbon atoms which may have a substituent.,

[0022] R 1 or R 2 at least one of them may contain a photopolymerizable unsaturated group. R 1 and R 2 containing a photopolymerizable unsaturated group may be, for example, an alkyl group having 1 to 10 carbon atoms having an acryloyloxy group as a substituent, or an alkyl group having 1 to 10 carbon atoms having a methacryloyloxy group as a substituent.,

[0023] The weight average molecular weight of the polyimide precursor may be 5000 or more and 100000 or less. The weight average molecular weight of the polyimide precursor may be 6000 or more, 7000 or more, 8000 or more, 9000 or more, 10000 or more, or 11000 or more, and may also be 90000 or less, 80000 or less, 70000 or less, 60000 or less, 50000 or less, 40000 or less, 30000 or less, or 20000 or less. The weight average molecular weight here is a conversion value based on the calibration curve of standard polystyrene determined by gel permeation chromatography (GPC).

[0024] The polyimide precursor can be synthesized by a usual method including, for example, a polymerization reaction between an acid anhydride monomer and an amine monomer. The acid anhydride monomer may contain an acid anhydride compound represented by the following formula (20), and the amine monomer may contain a diamine compound represented by the following formula (30). X in formula (20) 1 and X in formula (30) 2、Or when both of these contain a dicyclopentadienediyl group, a polyimide precursor having a structural unit containing a dicyclopentadienediyl group can be obtained.

Chemical formula

[0025] The acid anhydride compound represented by formula (20) may be, for example, a compound represented by the following formula (20a) or (20b). X in formula (20a) 3 , L, Ar 1 , Ar 2 and n are the same as X in formula (II) 3 , L, Ar 1 , Ar 2 and n are defined. X in formula (20b) 3 , L, X 4 , R 5 and n are the same as X in formula (III) 3 , L, X 4 , R 5 and n are defined.

Chemical formula

Chemical formula

[0026] Examples of the compound represented by formula (20a) include acid anhydride compounds represented by the following formula (21) or (22). R in formula (21) and (22) 3 , R 4 , p, q and n are the same as R in formula (IIa) or (IIb) 3 , R 4 , p, q and n are defined.

Chemical formula

Chemical formula

[0027] By forming an imide ring in at least a part of the structural units constituting the polyimide precursor, a polyimide having a polymer chain containing a structural unit containing an imide ring can be formed. The polyimide to be formed contains, for example, a structural unit represented by the following formula (IA). X in formula (IA) 1 and X 2 can be the same groups as X 1 and X 2 in formula (I). The imidization reaction involving the formation of an imide ring can be advanced by heating. [Chemical formula]

[0028] A polyimide molded article containing polyimide can be produced by a method including forming an intermediate molded article containing a polyimide precursor and heating the intermediate molded article to form an imide ring in at least a part of the structural units represented by formula (I) in the polyimide precursor.

[0029] The intermediate molded article containing a polyimide precursor can be formed, for example, by a method including preparing a polyimide precursor composition containing a polyimide precursor and an organic solvent, imparting a shape to the polyimide precursor composition, and then removing the organic solvent from the polyimide precursor composition. The polyimide molded article may be a polyimide film. In that case, for example, a film-shaped intermediate molded article may be formed by a method including removing the organic solvent by heating from a resin film containing the polyimide precursor composition. A small amount of the organic solvent may remain in the intermediate molded article. At the stage of the intermediate molded article, the imidization reaction may proceed partially.

[0030] The organic solvent contained in the polyimide precursor composition may be a solvent that dissolves the polyimide precursor. Examples of the organic solvent include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetramethylurea, hexamethylphosphoric triamide, γ-butyrolactone, δ-valerolactone, γ-valerolactone, cyclohexanone, cyclopentanone, tetrahydrofuran, propylene glycol monomethyl ether acetate, propylene carbonate, ethyl lactate, and 1,3-dimethyl-2-imidazolidinone. The content of the organic solvent in the polyimide precursor composition may be, for example, 40% by mass or more and 80% by mass or less based on the mass of the polyimide precursor composition.

[0031] The polyimide precursor composition may further contain other components such as a silane coupling agent, a photo radical polymerization initiator, and a photopolymerizable monomer, if necessary.

[0032] The heating temperature for forming the polyimide molded body from the intermediate molded body is adjusted so that the imidization reaction proceeds sufficiently. The heating temperature may be, for example, 200°C or higher and 350°C or lower. In the polyimide molded body after heating, structural units that do not form imide rings may remain.

[0033] The polyimide molded body may be a polyimide film. In that case, the polyimide film can be applied, for example, as a substrate or an insulating resin layer constituting an electronic component. The polyimide film may be a substrate (particularly a transparent substrate) of an image display device. The insulating resin layer made of the polyimide film may be a protective film that protects the wiring of an electronic component. Since the polyimide molded body exhibits a low dielectric tangent, it is particularly useful as a member of an electronic component for a high-frequency band.

Examples

[0034] The present invention is not limited to the following examples. 1. Measurement method Infrared absorption (FT-IR) spectrum The infrared absorption spectrum of the acid anhydride compound was measured by the KBr plate method using a Fourier transform infrared spectrophotometer (FT-IR4100, manufactured by JASCO Corporation).

[0035] 1 1H-NMR spectrum of the acid anhydride compound 1 The 1H-NMR spectrum of the acid anhydride compound was measured using an NMR spectrometer (AV400M, manufactured by Bruker BioSpin) with deuterated dimethyl sulfoxide (DMSO-d6) as the solvent.

[0036] Weight average molecular weight (Mw) The weight average molecular weight (Mw) of the polyimide precursor was determined as a value converted from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The calibration curve was approximated by a cubic equation using standard polystyrene: TSKstandard POLYSTYRENE (Type; A-2500, F-4, F-10, F-40, F-850) (manufactured by Tosoh Corporation, trade name). The measurement conditions of GPC were as follows. Apparatus: High-speed GPC apparatus HLC-8320GPC (manufactured by Tosoh Corporation, trade name) Detector: Ultraviolet absorption detector UV-8320 (manufactured by Tosoh Corporation, trade name) Column; Gelpack GL-S300MDT-5×2 Eluent: DMF / tetrahydrofuran = 1:1 (vol) + 0.06 M phosphoric acid + 0.06 M lithium bromide Sample concentration: 10 mg / 2 mL Injection volume: 50 μL Flow rate: 1.0 mL / min Measurement temperature: 40 °C

[0037] 5% weight loss temperature (Td 5 ) Using a thermogravimetric analyzer (STA7300, manufactured by Hitachi High-Tech Science Corporation), in an air stream, during the temperature rising process at a temperature rising rate of 10 °C / min, the temperature at which the weight of the polyimide film decreased by 5% with respect to the initial weight was defined as the 5% weight loss temperature (Td 5) was recorded as the Td measured in air. 5 A high value of this means high chemical heat resistance and suppression of the generation of volatile organic compounds (VOCs) up to higher temperatures.

[0038] Dielectric constant (ε r ), dielectric loss tangent (tanδ) For the polyimide film immediately after drying at 105 °C for 1 hour, the relative dielectric constant (Dk) and dielectric loss tangent (Df) were measured in the 10 GHz band at an ambient temperature of 25 °C using a split cylinder resonator. As the measuring instruments, a vector network analyzer MS46122B manufactured by Anritsu Corporation and a 10 GHz split cylinder resonator (TE mode) manufactured by AET Corporation were used.

[0039] 2. Synthesis of acid anhydride compounds Example 1-1 [Chemical formula]

[0040] Under a nitrogen atmosphere, 7.93 g of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (H-TMAn-S, 40 mmol, manufactured by Mitsubishi Gas Chemical Company, Inc.), 80 mL of thionyl chloride (excess, manufactured by Tokyo Chemical Industry Co., Ltd.) and 5 drops of N,N-dimethylformamide (DMF, manufactured by Tokyo Chemical Industry Co., Ltd.) as a catalyst were placed in a 300 mL eggplant-shaped flask. The reaction was allowed to proceed by refluxing at 80 °C for 3 hours in a nitrogen atmosphere to obtain a yellow transparent solution. Toluene was added as an azeotropic agent to the solution, and thionyl chloride was distilled off by azeotropy. Crystals were formed by recrystallization in cyclohexane. The crystals were taken out by filtration and vacuum dried at 60 °C for 12 hours to obtain white crystals containing the acid chloride formed from H-TMAn-S (yield 60%).

[0041] Under a nitrogen atmosphere, 25.62 g of dicyclopentadiene-type phenolic resin (150 mmol), 50 mL of dehydrated THF (manufactured by Fujifilm Wako Pure Chemical Corporation) without a stabilizer, and 18.2 mL of dehydrated pyridine (225 mmol, manufactured by Fujifilm Wako Pure Chemical Corporation) were placed in a 500 mL eggplant-shaped flask to form Solution A. In a 100 mL eggplant-shaped flask, 38.99 g of acid chloride (180 mmol) was dissolved in 100 mL of dehydrated THF without a stabilizer to form Solution B. While stirring Solution A in the eggplant-shaped flask in an ice bath, Solution B was slowly added dropwise to Solution A over 2 hours. The reaction solution in the eggplant-shaped flask was further stirred at room temperature for 4 hours. The precipitated precipitate was taken out by filtration and washed with THF to remove excess acid chloride. Finally, it was washed thoroughly with water to completely remove pyridine hydrochloride, which is a by-product. The washed precipitate was vacuum-dried at 160 °C for 12 hours to obtain a reddish-brown powder containing the product (yield 65%). From the analysis results by FT-IR and 1 1H-NMR, it was confirmed that the product is an acid anhydride compound represented by formula (21a). FT-IR (KBr plate method, cm-1): 2951 (aromatic C-H stretching), 1863 / 1786 (acid anhydride group, C=O stretching), 1751 (ester group, C=O stretching). 1H-NMR (400 MHz, DMSO-d6, δ, ppm): 7.02~7.25 (m, 8H), 3.52 (m, 2H), 3.28 (m, 2H), 1.25~2.78 (m, 28H).

[0042] Example 1-2

Chemical formula

[0043] Under a nitrogen atmosphere, 29.00 g of dicyclopentadiene-type paracresol resin (150 mmol), 50 mL of dehydrated THF without a stabilizer (manufactured by FUJIFILM Wako Pure Chemical Corporation), and 18.2 mL of dehydrated pyridine (225 mmol, manufactured by FUJIFILM Wako Pure Chemical Corporation) were placed in a 500 mL eggplant-shaped flask to form Solution A. In a 100 mL eggplant-shaped flask, 41.06 g of trimellitic anhydride chloride (195 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 100 mL of dehydrated THF without a stabilizer to form Solution B. While stirring Solution A in the eggplant-shaped flask in an ice bath, Solution B was slowly added dropwise to Solution A over 2 hours. The reaction solution in the eggplant-shaped flask was further stirred at room temperature for 4 hours. The precipitated precipitate was taken out by filtration and washed with THF to remove excess acid chloride. Finally, it was thoroughly washed with water to completely remove pyridine hydrochloride as a by-product. The washed precipitate was vacuum dried at 160 °C for 12 hours to obtain a reddish-brown powder containing the product (yield 52%). From the analysis results by FT-IR and 1H-NMR, it was confirmed that the product was an acid anhydride compound represented by formula (22a). FT-IR (KBr plate method, cm-1): 2947 (aromatic C-H stretching), 1863 / 1786 (acid anhydride group, C=O stretching), 1739 (ester group, C=O stretching). 1 1H-NMR (400 MHz, DMSO-d6, δ, ppm): 8.46~8.4 (d, 2H), 8.39 (s, 2H), 8.18~8.20 (d, 2H), 7.00~7.10 (m, 6H), 2.70 (s, 6H), 0.98~2.25 (m, 14H).

[0044] 3. Synthesis of polyimide precursor Example 2-1 In a dry and sealed reaction vessel, a powder (10 mmol) containing the acid anhydride compound represented by the formula (21a) synthesized in Example 1-1 was dissolved in NMP dehydrated with molecular sieves 4A. While stirring the formed solution with a magnetic stirrer, an NMP solution containing 4,4'-diaminodiphenyl ether (4,4'-ODA, 10 mmol) was added to the solution, and stirring was continued. The total concentration of the acid anhydride compound and 4,4'-ODA was 30% by mass. By stirring at room temperature for 24 hours, a uniform and viscous varnish (polyimide precursor composition) containing a polyimide precursor was obtained.

[0045] Example 2-2 A varnish (polyimide precursor composition) containing a polyimide precursor was obtained in the same procedure as in Example 2-1, except that a powder containing the acid anhydride compound represented by the formula (22a) synthesized in Example 1-2 was used as the acid anhydride compound.

[0046] Comparative Example 1 A varnish (polyimide precursor composition) containing a polyimide precursor was obtained in the same procedure as in Example 2-1, except that 2-methyl-1,4-phenylene bis(trimellitate anhydride) represented by the following formula (41) was used as the acid anhydride compound.

Chemical formula

[0047] Comparative Example 2 A varnish (polyimide precursor composition) containing a polyimide precursor was obtained in the same procedure as in Example 2-1, except that p-phenylene bis(trimellitate anhydride) represented by the following formula (42) was used as the acid anhydride compound.

Chemical formula

[0048] Comparative Example 3 A varnish (polyimide precursor composition) containing a polyimide precursor was obtained in the same procedure as in Example 2-1, except that 1,2,4,5-cyclohexanetetracarboxylic dianhydride (H-PMDA) was used as the acid anhydride compound.

Chemical formula

[0049] Comparative Example 4 A varnish (polyimide precursor composition) containing a polyimide precursor was obtained in the same procedure as in Example 2-1, except that 1,2,4,5-cyclohexanetetracarboxylic dianhydride (H-PMDA) was used as the acid anhydride compound and 4,4'-diaminodiphenylmethane (MDA) was used as the amine.

[0050] Comparative Example 5 A varnish (polyimide precursor composition) containing a polyimide precursor was obtained in the same procedure as in Example 2-1, except that pyromellitic dianhydride (PMDA) was used as the acid anhydride compound and 4,4'-methylenebis(cyclohexylamine) (DCHM) was used as the amine.

Chemical formula

[0051] 4. Polyimide Film The varnish obtained in each example or comparative example was applied to a glass substrate, and the coating film was dried at 110 °C for 1 hour in a hot air dryer to form a cast film (intermediate molded body) containing a polyimide precursor. The cast film on the glass substrate was placed in an electric furnace. In the evacuated electric furnace, imidization was allowed to proceed by heating at 250 °C for 1 hour and then at 350 °C for 1 hour. The film was peeled off from the glass substrate to obtain a flexible polyimide film with a thickness of 25 μm and no turbidity.

[0052] 5. Evaluation The weight average molecular weight (Mw) of the polyimide precursor and the 5% weight loss temperature (Td) of the polyimide film 5) The dielectric constant (Dk) and the dissipation factor (Df) were measured. The measurement results are shown in Table 1.

[0053]

Table 1

[0054] The polyimide films of Examples 2-1 and 2-2 exhibited a high 5% weight loss temperature (Td 5 ) around 400 °C and had sufficiently high chemical heat resistance and long-term heat resistance. The polyimide films of Examples 2-1 and 2-2 showed a significantly lower dissipation factor compared to the polyimide film of the comparative example. This is considered to be due to the restriction of the in-plane orientation of the polyimide by the introduction of a rigid and bulky skeleton such as the dicyclopentadienediyl group. When the in-plane orientation is restricted, the free volume increases and the density of imide groups with high molar polarization decreases. This is considered to have contributed to the improvement of the dielectric properties.

Claims

1. The following formula (I): 【Chemical formula 1】 containing a structural unit represented by, X １ represents a tetravalent organic group, X ２ represents a divalent organic group, R １ and R ２ each independently represents a hydrogen atom or a monovalent organic group, X １ or X ２ at least one of which is the following formula (10): 【Chemical formula 2】 containing a dicyclopentadienediyl group represented by, polyimide precursor.

2. X １ contains the dicyclopentadienediyl group, the polyimide precursor according to claim 1.

3. X １ is an organic group containing a group represented by the following formula (II): 【Chemical formula 3】 where * represents a bond, X ３ represents a trivalent organic group containing two adjacent carbon atoms, L represents a direct bond or a divalent linker group, Ar １ represents a divalent aromatic group which may have a substituent, Ar ２ represents a trivalent aromatic group which may have a substituent, n represents an integer of 0 or more, and a plurality of Xs ３ in the same molecule, L, Ar １ and Ar ２ may be the same or different from each other, and two bonds * bonded to one X ３ are respectively bonded to two adjacent carbon atoms in X ３ and two combinations of two bonds * bonded to one X ３ are the four bonds of X １ in formula (I), the polyimide precursor according to claim 1.

4. A polyimide precursor composition comprising the polyimide precursor according to claim 1 and an organic solvent.

5. Forming an intermediate molded body comprising the polyimide precursor according to claim 1; By heating the intermediate molded body, forming an imide ring in at least a part of the structural units represented by the formula (I) in the polyimide precursor; A method for producing a polyimide molded body, comprising:

6. The following formula (IA): 【Chemical formula 4】 Containing a structural unit represented by, X １ represents a tetravalent organic group, X ２ represents a divalent organic group, X １ Or X ２ At least one of which is the following formula (10): 【Chemical formula 5】 Containing a dicyclopentadienediyl group represented by, Polyimide.

7. X １ The polyimide according to claim 6, wherein contains the dicyclopentadienediyl group.

8. X １ is an organic group containing a group represented by the following formula (II): 【Chemical formula 6】 where * represents a bond, X ３ represents a trivalent organic group containing two adjacent carbon atoms, L represents a direct bond or a divalent linker group, Ar １ represents a divalent aromatic group which may have a substituent, Ar ２ represents a trivalent aromatic group which may have a substituent, n represents an integer of 0 or more, and a plurality of Xs in the same molecule ３ , L, Ar １ And Ar ２ May be the same or different from each other, and the two bonds * bonded to one X ３ are X ３which are respectively bonded to two adjacent carbon atoms and one X ３ Among the combinations of two bonds * bonded to ３ , two combinations are the four bonds of X in formula (I) １ The polyimide according to claim 6

9. A polyimide molded article comprising the polyimide according to claim 6

10. The polyimide molded article according to claim 9, which is a polyimide film

11. The following formula (21): 【Chemical formula 7】 represented, where R ３ and R ４ each independently represent an alkyl group having 1 to 5 carbon atoms, p represents an integer of 0 to 4, q represents an integer of 0 to 3, n represents an integer of 0 or more, and a plurality of R's in the same molecule ３ and R ４ may be the same or different, an acid anhydride compound

12. The following formula (22): 【Chemical formula 8】 represented, where R ３ and R ４ each independently represent an alkyl group having 1 to 5 carbon atoms, p represents an integer of 0 to 4, q represents an integer of 0 to 3, n represents an integer of 0 or more, and a plurality of R's in the same molecule ３ and R ４ may be the same or different, an acid anhydride compound

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