Polyimide precursor, resin composition, polyimide molding, method for manufacturing polyimide molding and electronic component

Abstract

To provide a new polyimide precursor which enables formation of a polyimide molding that is excellent in dielectric characteristics at high frequency.SOLUTION: A polyimide precursor is a reactant of a tetracarboxylic acid dianhydride having an indane skeleton and diamine.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a polyimide precursor, a resin composition, a polyimide molded article, a method for producing a polyimide molded article, and an electronic component.

Background Art

[0002] As a material for a protective film and an insulating film of a semiconductor device, a polyimide resin is widely applied (for example, Patent Document 1). A protective film or an insulating film using such a polyimide resin is obtained by heating a resin film formed by applying and drying a polyimide precursor or a resin composition containing a polyimide precursor on a substrate to cure it.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to provide a novel polyimide precursor capable of forming a polyimide molded article excellent in dielectric properties at high frequencies.

Means for Solving the Problems

[0005] The present disclosure includes the following [1] to [8]. [1] A polyimide precursor which is a reaction product of a tetracarboxylic dianhydride having an indane skeleton and a diamine. [2] The polyimide precursor according to [1] above, having a weight average molecular weight of 2,000 or more and 100,000 or less. [3] A resin composition containing the polyimide precursor according to [1] or [2] above. [4] The resin composition according to [3] above, further containing an organic solvent. [5] A polyimide molded article, which is a cured product of the polyimide precursor described in [1] or [2] above. [6] A polyimide molded article, which is a cured product of the resin composition described in [3] or [4] above. [7] A method for producing a polyimide molded article, comprising a step of applying and drying the resin composition described in [3] or [4] above on a substrate to form a resin film, and a step of heat-treating the resin film. [8] An electronic component comprising an insulating film containing the polyimide molded article described in [6] above.

Advantages of the Invention

[0006] According to the present disclosure, it is possible to provide a novel polyimide precursor capable of forming a polyimide molded article excellent in dielectric properties at high frequencies (for example, 10 GHz or higher).

Embodiments for Carrying Out the Invention

[0007] Hereinafter, embodiments of the present disclosure will be described. However, the present disclosure is not limited to the following embodiments.

[0008] In this specification, a numerical range indicated by "~" indicates a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value of a certain stepwise numerical range may be replaced with the upper limit value or the lower limit value of another stepwise numerical range. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. Further, the individually described upper limit value and lower limit value can be arbitrarily combined. In the notation of the numerical range "A~B", the numerical values A and B at both ends are included in the numerical range as the lower limit value and the upper limit value, respectively. In this specification, for example, the description "10 or more" means "10" and "a numerical value exceeding 10", and the same applies when the numerical values are different. Further, for example, the description "10 or less" means "10" and "a numerical value less than 10", and the same applies when the numerical values are different.

[0009] [Polyimide Precursor] The polyimide precursor according to this embodiment is a reaction product of a tetracarboxylic dianhydride having an indane skeleton (hereinafter also referred to as “component (a1)”) and a diamine (hereinafter also referred to as “component (a2)”).

[0010] Since the polyimide precursor according to this embodiment includes a structural unit derived from a tetracarboxylic dianhydride having a rigid and bulky indane skeleton, a polyimide molded body having a large free volume and a reduced content of imide groups with high molar polarization can be formed, so that a polyimide molded body excellent in dielectric properties can be provided.

[0011] Component (a1) may be a tetracarboxylic dianhydride having one indane skeleton, or may be a tetracarboxylic dianhydride having two or more indane skeletons. Examples of component (a1) include compounds represented by the following formula (I).

[0012] [Chemical formula]

[0013] In formula (I), X 1 represents a divalent organic group having an indane skeleton, X 2 represents a trivalent organic group, and L represents a direct bond or a divalent linker group. A plurality of X 2 and L in the same molecule may be the same or different from each other.

[0014] Examples of the divalent organic group having an indane skeleton represented by X 1 include a group represented by the following formula (1) and a group represented by the following formula (2). From the viewpoint of dielectric properties, X 1 may be a group represented by the following formula (1). From the viewpoint of heat resistance, X 1 may be a group represented by the following formula (2).

[0015] [Chemical formula]

[0016] [Chemical formula]

[0017] In formulas (1) and (2), R 1 represents a divalent organic group, and * represents a bond. R 1 The divalent organic group represented by may be a divalent aromatic group or a divalent aliphatic group. From the viewpoints of heat resistance and dielectric properties, R 1 may be a divalent aromatic group. Examples of R 1 include, for example, a phenylene group, a biphenyldiyl, and a naphthalenediyl.

[0018] In formulas (1) and (2), the hydrogen bonded to the carbon atom constituting the indane ring may be substituted by a substituent. Examples of the substituent include an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, and a mercapto group.

[0019] Examples of the group represented by formula (1) include a group represented by the following formula (1-1).

[0020] [Chemical formula]

[0021] In formula (1-1), R 1 is the same as R 1 in the above formula (1), and R 2 ~R 4is, independently, a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group, and * represents a bond. From the viewpoints of heat resistance and dielectric properties, R 2 ~R 4 may each independently be an alkyl group having 1 to 10 carbon atoms (for example, an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 3 carbon atoms, or a methyl group).

[0022] Examples of the group represented by formula (2) include a group represented by the following formula (2-1).

[0023]

Chemical formula

[0024] In formula (2-1), R 7 ~R 8 is, independently, a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group, and * represents a bond. From the viewpoints of heat resistance and dielectric properties, R 7 ~R 8 may each independently be an alkyl group having 1 to 10 carbon atoms (for example, an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 3 carbon atoms, or a methyl group).

[0025] X 2 Examples of X include an alicyclic group which may have a substituent, and an aromatic group which may have a substituent. The substituent that the alicyclic group or aromatic group as X has may be 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). X 2 The substituent that the alicyclic group or aromatic group as X has may be 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). X 2may be a residue of a tricarboxylic anhydride. X 2 Examples of the tricarboxylic anhydride that induces 2 include cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, trimellitic anhydride, octahydro-4-methyl-1,3-dioxo-5-isobenzofurancarboxylic acid, and 1,3-dihydro-4-methyl-1,3-dioxo-5-isobenzofurancarboxylic acid.

[0026] L may be a direct bond or a linker group selected from a carboxylic acid ester group (-C(=O)O-) and a carboxylic acid amide group (-C(=O)NH-).

[0027] Specific examples of the compound represented by formula (I) include the compound represented by the following formula (I-1) and the compound represented by the following formula (I-2).

[0028]

Chemical formula

Chemical formula

[0029] In formulas (I-1) and (I-2), X 1 is the same as X in formula (I). 1 Specific examples of the compound represented by formula (I-1) include the compounds represented by the following formulas (a) and (b), and specific examples of the compound represented by formula (I-2) include the compounds represented by the following formulas (c) and (d). In formulas (a) to (d), R 2 to R 4 are the same as R 2 to R 4 in formula (1-1), respectively, and R 7 to R 8 are the same as R 7 to R 8 in formula (2-1), respectively.

[0030]

Chemical formula

Chem.

Chem.

Chem.

[0031] (Component (a1)) can be obtained, for example, by reacting a compound having an indane skeleton and a phenolic hydroxyl group with a tricarboxylic dianhydride. Examples of the compound having an indane skeleton and a phenolic hydroxyl group include indane-type phenolic resin TMHI (product name, manufactured by JFE Chemical Corporation) and spirobiindane-type phenolic resin SPI (product name, manufactured by JFE Chemical Corporation). Examples of the tricarboxylic dianhydride include cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride and trimellitic anhydride.

[0032] (Component (a2)) is not particularly limited and can be appropriately selected according to the required properties and uses. From the viewpoint of high elongation, a diamine having a structure derived from dimethylsiloxane or a diamine having a structure derived from diphenyl ether may be used. From the viewpoint of improving UV ablation properties, a diamine having a structure derived from biphenyl may be used. From the viewpoint of alkali solubility, a diamine having a phenolic hydroxyl group may be used. From the viewpoint of high refractive index, a diamine having a polycyclic aromatic group or a diamine containing a heavy element may be used. (Component (a2)) may be a commercially available product. (Component (a2)) may be used alone or in combination of two or more.

[0033] Examples of (Component (a2)) include aromatic diamines and aliphatic diamines. An aromatic diamine means a diamine having an aromatic ring, and an aliphatic diamine means a diamine having no aromatic ring.

[0034] Examples of the aromatic diamine include 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl methane, 4,4'-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(p-amino-phenyl) octamethylpentasiloxane, and bis(3-amino-4-hydroxyphenyl)fluorene.

[0035] Examples of the aliphatic diamine include bis(3-aminopropyl)tetramethyldisiloxane, 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, 1,12-diaminododecane, and 1,2-bis(2-aminoethoxy)ethane.

[0036] From the viewpoint of heat resistance, the weight average molecular weight (Mw) of the polyimide precursor may be 2000 or more, 2500 or more, 3000 or more, 3500 or more, 4000 or more, or 4500 or more. From the viewpoint of solvent solubility, it may be 100000 or less, 70000 or less, 50000 or less, 20000 or less, 10000 or less, or 8500 or less. The Mw of the polyimide precursor may be 2000 or more and 100000 or less, 2500 or more and 70000 or less, 3000 or more and 50000 or less, 3500 or more and 20000 or less, 4000 or more and 10000 or less, or 4500 or more and 8500 or less. Mw can be measured by the method shown in the examples.

[0037] The polyimide precursor (polyamic acid) according to this embodiment can be obtained by polymerizing a tetracarboxylic dianhydride having an indane skeleton and a diamine. The polyimide precursor according to this embodiment can be produced, for example, by adding a diamine solution obtained by dissolving a predetermined amount of diamine in a solvent to an acid anhydride solution obtained by dissolving a predetermined amount of tetracarboxylic dianhydride in a solvent and stirring.

[0038] The solvent used when synthesizing the polyimide precursor is not particularly limited as long as it can dissolve the diamine, tetracarboxylic dianhydride, and the resulting polyimide precursor. Examples of such solvents include aprotic solvents, phenolic solvents, ethers, and glycol solvents.

[0039] Examples of the aprotic solvent include amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazolidinone, and tetramethylurea; lactone solvents such as γ-butyrolactone and γ-valerolactone; phosphorus-containing amide solvents such as hexamethylphosphoric amide and hexamethylphosphine triamide; sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide, and sulfolane; ketone solvents such as cyclohexanone and methylcyclohexanone; tertiary amine solvents such as picoline and pyridine; and ester solvents such as (2-methoxy-1-methylethyl) acetate. Examples of the phenolic solvent include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol. Examples of the ether and glycol solvents include 1,2-dimethoxyethane, bis(2-methoxyethyl) ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl] ether, tetrahydrofuran, and 1,4-dioxane. Among these, N-methyl-2-pyrrolidone is preferred from the viewpoints of solubility and film-forming property. These solvents can be used alone or in combination of two or more kinds.

[0040] The reaction temperature and reaction time of the polymerization reaction for obtaining the polyimide precursor can be appropriately adjusted according to the types of the tetracarboxylic dianhydride and diamine used. The reaction temperature may be -30 to 200°C, 20 to 180°C, or 25°C to 100°C. The reaction time may be 3 to 100 hours. The end point of the reaction may be the point when stirring is continued at room temperature (25°C) or an appropriate reaction temperature and the viscosity of the product (polyimide precursor) becomes constant. The viscosity can be measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) at 25°C.

[0041] [Resin Composition] The resin composition according to this embodiment contains the above polyimide precursor. The resin composition according to this embodiment may further contain an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the polyimide precursor, and the same solvent as that used in the synthesis of the above polyimide precursor may be used.

[0042] From the viewpoint of film-forming property, the content of the polyimide precursor in the resin composition may be 5 to 60% by mass, 10 to 50% by mass, or 20 to 40% by mass. The content of the polyimide precursor can be calculated by the following method. That is, take the resin composition in a metal petri dish (about 1 g as a guide) with a known mass in advance, measure the mass (the mass of the metal petri dish and the resin composition, hereinafter referred to as the "mass before heating"), and then heat it on a hot plate for 2 hours until the solvent and the like have sufficiently volatilized, and measure the mass (the mass of the metal petri dish and the polyimide precursor, hereinafter referred to as the "mass after heating"), and it can be calculated by (mass after heating - mass of the metal petri dish) ÷ (mass before heating - mass of the metal petri dish) × 100.

[0043] The content of the organic solvent in the resin composition may be an amount such that the viscosity of the resin composition at 25°C is 0.5 Pa·s to 100 Pa·s.

[0044] In addition to the polyimide precursor and the organic solvent, the resin composition according to this embodiment may further contain other additives according to the application, as long as the effects of the present invention are not impaired. The resin composition according to this embodiment may be a photosensitive resin composition (for example, a photosensitive resin composition for forming an insulating film). In this case, examples of other additives include a photo radical generator, a crosslinking agent, a coupling agent, a rust inhibitor, a radical polymerization inhibitor, and a radical polymerization suppressant.

[0045] The manufacturing method of the resin composition according to this embodiment is not particularly limited and can be manufactured by known methods. For example, when the resin composition contains an organic solvent and the organic solvent is the same as the solvent used in the production of the polyimide precursor, the polyimide precursor is produced in the organic solvent, and the same organic solvent and, if necessary, additives are added to the obtained polyimide precursor solution in the temperature range of room temperature to 80°C, and stirred and mixed to produce the resin composition. In this case, a device such as a three-one motor (manufactured by Shin-Toyo Chemical Co., Ltd.) equipped with a stirring blade or a rotating and revolving mixer can be used for stirring and mixing. Also, heat of 40 to 100°C may be applied if necessary.

[0046] In addition to the above, when the solvent used in the production of the polyimide precursor is different from the organic solvent of the resin composition, the solvent of the produced polyimide precursor solution is removed by reprecipitation or evaporation to obtain only the polyimide precursor, and an organic solvent and, if necessary, additives are added to this polyimide precursor in the temperature range of room temperature to 80°C, and stirred and mixed to produce the resin composition.

[0047] From the viewpoint of workability in the coating process, the resin composition according to this embodiment may have a viscosity at 25°C of 0.5 to 100 Pa·s, 1 to 30 Pa·s, or 5 to 20 Pa·s.

[0048] [Polyimide molded article] The polyimide molded article according to this embodiment can be obtained by a manufacturing method including a step of applying and drying the above polyimide precursor or the above resin composition on a substrate to form a resin film, and a step of heat-treating (thermal imidization) the resin film. The polyimide molded article according to this embodiment may be a cured product of the above polyimide precursor or a cured product of the above resin composition.

[0049] The base material is not particularly limited as long as it has heat resistance to the drying temperature in subsequent drying and has good peelability. For example, base materials made of glass, silicon wafers, etc., and supports made of PET (polyethylene terephthalate), OPP (oriented polypropylene), etc. can be mentioned. As the base material, for example, metal substrates such as glass substrates, stainless steel, alumina, copper, nickel, etc.; resin substrates such as polyethylene glycol terephthalate, polyethylene glycol naphthalate, polycarbonate, polyimide, polyamideimide, polyetherimide, polyetheretherketone, polyethersulfone, polyphenylene sulfone, polyphenylene sulfide, etc. can be used.

[0050] The coating method is not particularly limited, and a known coating method can be appropriately selected and used according to the desired coating thickness, viscosity of the resin composition, etc. As the coating method, for example, coating methods such as doctor blade knife coater, air knife coater, roll coater, rotary coater, flow coater, die coater, bar coater, etc.; coating methods such as spin coating, spray coating, dip coating, etc.; printing techniques represented by screen printing, gravure printing, etc. can be mentioned.

[0051] The coating thickness of the resin composition can be appropriately adjusted according to the thickness of the target molded body and the ratio of the resin non-volatile component in the resin composition. The coating thickness may be, for example, 1 to 1000 μm. The coating may be carried out at room temperature, or the resin composition may be heated in the range of 40 to 80 °C for the purpose of reducing the viscosity and improving workability.

[0052] For drying, devices such as hot plates, box-type dryers, conveyor-type dryers, etc. can be used. The drying temperature may be 80 to 200 °C or 100 to 150 °C.

[0053] In the heat treatment, by heating the resin film obtained by drying, the organic solvent remaining in the resin film is removed, and the imidization reaction of the polyimide precursor in the resin film is advanced to obtain a cured film (polyimide molded body). The heat treatment may be carried out simultaneously or sequentially with the above drying.

[0054] As the heating means, apparatuses such as an inert gas oven, a hot plate, a box dryer, a conveyor dryer, etc. can be used. The heating temperature may be 250°C to 400°C or 300 to 350°C. When the heating temperature is 250°C or higher, imidization can be sufficiently performed. When the heating temperature is 400°C or lower, the transparency and heat resistance of the obtained polyimide molded body can be improved. The heating time may be 0.5 to 3 hours. The heating may be performed by gradually raising the temperature step by step. The heating atmosphere may be an air atmosphere, but from the viewpoints of safety and oxidation prevention, it may also be performed under a vacuum or an inert gas atmosphere. Examples of the inert gas include nitrogen and argon.

[0055] The amount of residual organic solvent in the polyimide molded body after heating may be 2% by mass or less, 1% by mass or less, or 0.5% by mass or less. The amount of residual organic solvent in the polyimide molded body can be measured using differential thermal thermogravimetric simultaneous measurement (TG-DTA) and gas chromatograph mass spectrometry (GC-MS).

[0056] If necessary, a peeling step of peeling the polyimide molded body from the substrate may be further provided. The peeling of the polyimide molded body may be performed after cooling the laminate of the substrate and the polyimide molded body to about room temperature to 50°C after the heat treatment.

[0057] From the viewpoint of facilitating the peeling step, a release agent may be applied to the substrate as necessary before coating. Examples of the release agent include release agents such as vegetable oil-based, silicone-based, fluorine-based, and alkyd-based release agents.

[0058] The shape of the polyimide molded body is not particularly limited, and depending on the usage and purpose of use, it may be in the form of a film or a sheet.

[0059] The polyimide molded body formed using the polyimide precursor according to this embodiment not only has the original heat resistance and mechanical strength of polyimide, but also has excellent dielectric properties in the high-frequency band. Therefore, it can be suitably used for electronic material applications in the high-frequency band (for example, insulating films and protective films of electronic components such as semiconductor elements). Further, the polyimide molded body formed using the polyimide precursor according to this embodiment is also excellent in transparency, so it can be suitably used for transparent substrates of electronic components.

Examples

[0060] Hereinafter, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to these examples.

[0061] [Synthesis of Tetracarboxylic Dianhydride Having Indan Skeleton] (Synthesis Example 1) Under a nitrogen atmosphere, 7.93 g of H-TMAn-S (cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, 40 mmol, manufactured by Mitsubishi Gas Chemical Company, Inc.), 80 mL of thionyl chloride (excess amount, 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, and refluxed at 80 °C for 3 hours in a nitrogen atmosphere to obtain a yellow transparent solution. Then, toluene was added as an azeotropic agent, and thionyl chloride was distilled off azeotropically. Next, recrystallization treatment using cyclohexane was performed, and the obtained crystals were filtered off. The crystals were vacuum dried at 60 °C for 12 hours to obtain the acid chloride of H-TMAn-S as white crystals (yield 60%).

[0062] Under a nitrogen atmosphere, 12.34 g of spirobiindane-type phenolic resin SPI (40 mmol, product name, manufactured by JFE Chemical Corporation, a compound represented by the following formula (3)), 30 mL of dehydrated THF without a stabilizer (tetrahydrofuran, manufactured by Fujifilm Wako Pure Chemical Corporation), and 7.12 mL of dehydrated pyridine (88 mmol, manufactured by Fujifilm Wako Pure Chemical Corporation) were added to a 200 mL eggplant-shaped flask to prepare Solution A1. Next, 18.20 g (84 mmol) of the above acid chloride and 70 mL of dehydrated THF without a stabilizer were added to a 100 mL eggplant-shaped flask to prepare Solution B1. While stirring Solution A1 in an ice bath, Solution B1 was slowly added dropwise to Solution A1 over 2 hours. Then, the mixture was further stirred at room temperature for 4 hours. Next, the precipitated precipitate was filtered off, and the precipitate was washed with THF to remove excess acid chloride. After thoroughly washing with water to completely remove pyridine hydrochloride as a by-product, it was vacuum dried at 160 °C for 12 hours to obtain a reddish-brown product (yield 51%).

[0063] [Chemical formula]

[0064] It was confirmed by infrared absorption (IR) spectrum and 1 1H-NMR spectrum that the obtained product was a spirobiindane-type acid dianhydride (hereinafter also referred to as "acid anhydride 1") represented by the following formula (i). The IR spectrum was measured by the KBr plate method using a Fourier transform infrared spectrophotometer FT-IR4100 (manufactured by JASCO Corporation). 1 The 1H-NMR spectrum was measured using a NMR spectrometer AV400M (manufactured by Bruker BioSpin Corporation) with deuterated dimethyl sulfoxide (DMSO-d6) as the solvent. The results of the IR spectrum and 1 1H-NMR spectrum are shown below.

[0065] FT-IR (KBr plate method, cm -1 ): 2958 (aromatic C-H stretching), 1863 / 1789 (acid anhydride group, C=O stretching), 1747 (ester group, C=O stretching).

[0066] 1 H-NMR (400 MHz, DMSO-d6, δ, ppm): 7.36 (m, 2H), 6.96 (m, 2H), 6.49 (s, 2H), 3.52 (m, 4H), 3.31 (m, 2H), 1.31 - 2.66 (m, 26H).

[0067]

Chem.

[0068] (Synthesis Example 2) Under a nitrogen atmosphere, 7.93 g of 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, and refluxed at 80 °C for 3 hours in a nitrogen atmosphere to obtain a yellow transparent solution. Then, toluene was added as an azeotropic agent, and thionyl chloride was distilled off by azeotropy. Next, recrystallization treatment using cyclohexane was performed, and the obtained crystals were filtered off. The crystals were vacuum dried at 60 °C for 12 hours to obtain the acid chloride of H-TMAn-S as white crystals (yield 60%).

[0069] In a nitrogen atmosphere, 18.78 g of indane-type phenolic resin TMHI (70 mmol, product name, manufactured by JFE Chemical Corporation, the compound represented by the following formula (4)), 50 mL of dehydrated THF without stabilizer (manufactured by Fujifilm Wako Pure Chemical Corporation), and 12.46 mL of dehydrated pyridine (154 mmol, manufactured by Fujifilm Wako Pure Chemical Corporation) were added to a 200 mL eggplant-shaped flask to prepare Solution A2. Next, 31.84 g (147 mmol) of the above acid chloride and 70 mL of dehydrated THF without stabilizer were added to a 100 mL eggplant-shaped flask to prepare Solution B2. While stirring Solution A2 in an ice bath, Solution B2 was slowly added dropwise to Solution A2 over 2 hours. Then, it was further stirred at room temperature for 4 hours. Next, the precipitated precipitate was filtered off, and the precipitate was washed with THF to remove excess acid chloride. After thoroughly washing with water to completely remove pyridine hydrochloride as a by-product, it was vacuum dried at 160 °C for 12 hours to obtain a reddish-brown product (yield 55%).

[0070]

Chemical formula

[0071] It was confirmed by IR spectrum and 1 1H-NMR spectrum that the obtained product was an indane-type acid dianhydride (hereinafter also referred to as "acid anhydride 2") represented by the following formula (ii). The results of the IR spectrum and 1 1H-NMR spectrum are shown below.

[0072] FT-IR (KBr plate method, cm -1 ): 2954 (aromatic C-H stretching), 1863 / 1786 (acid anhydride group, C=O stretching), 1747 (ester group, C=O stretching).

[0073] 1 1H-NMR (400 MHz, DMSO-d6, δ, ppm): 7.26~7.28 (m, 3H), 6.99~7.02 (d, 4H), 3.35~3.50 (m, 4H), 3.08 (m, 2H), 1.29~2.65 (m, 17H), 1.15 (s, 3H), 0.95 (s, 3H).

[0074]

Chem.

[0075] [Example 1] (Preparation of Polyimide Precursor) In a dried and sealed reaction vessel, the powder of anhydride 1 obtained in Synthesis Example 1 (10 mmol) was dissolved in N-methyl-2-pyrrolidone (NMP) dehydrated with molecular sieves 4A, and while stirring with a magnetic stirrer, a NMP solution in which 4,4'-diaminodiphenyl ether (4,4'-ODA, 10 mmol) was dissolved was added, and stirring was continued. Stirring was carried out at room temperature for 24 hours to obtain a uniform and viscous polyimide precursor varnish (total solid concentration: 30% by mass). The Mw of the obtained polyimide precursor was 7900.

[0076] Mw was 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, product name). The measurement conditions of GPC are shown below. Apparatus: High-speed GPC apparatus HLC-8320GPC (manufactured by Tosoh Corporation, product name) Detector: Ultraviolet absorption detector UV-8320 (manufactured by Tosoh Corporation, product name) Column: Gelpack GL-S300MDT-5 (total 2 columns) 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

[0077] (Preparation of Polyimide Film) A varnish of the polyimide precursor was applied to a glass substrate and dried at 110 °C for 1 hour in a hot air dryer to obtain a cast film of the polyimide precursor. This was placed in an electric furnace together with the glass substrate and heated stepwise under vacuum, raising the temperature to 250 °C for 1 hour and then to 350 °C for 1 hour to effect thermal imidization. The obtained film was peeled off from the glass substrate to obtain a flexible polyimide film with a film thickness of 25 μm and no turbidity.

[0078] Separately, IR spectra before and after thermal imidization were measured using the cast film and the polyimide film. In the IR spectrum of the polyimide film, due to the thermal imidization treatment, the amide group C=O stretching vibration absorption bands around 1680 cm -1 and 1530 cm -1 completely disappeared, confirming that the thermal imidization reaction was completed under these heating conditions.

[0079] [Example 2] A polyimide precursor (Mw: 4700) and a polyimide film were prepared in the same manner as in Example 1, except that the acid anhydride 2 obtained in Synthesis Example 2 above was used as the acid anhydride.

[0080] [Comparative Example 1] A polyimide precursor (Mw: 30000) and a polyimide film were prepared in the same manner as in Example 1, except that 1,2,4,5-cyclohexanetetracarboxylic dianhydride (H-PMDA) was used as the acid anhydride.

[0081] [Comparative Example 2] A polyimide precursor (Mw: 24000) and a polyimide film were prepared in the same manner as in Example 1, except that H-PMDA was used as the acid anhydride and 4,4'-diaminodiphenylmethane (MDA) was used as the diamine.

[0082] [Evaluation] (5% weight loss temperature) Using a differential thermal and thermogravimetric simultaneous measurement device (STA7300, manufactured by Hitachi High-Tech Science Corporation), the temperature (Td 5 ) was measured when the mass of the polyimide film decreased by 5% by mass from the initial value during the temperature increase process in an air stream at a heating rate of 10 °C / min. The measurement results are shown in Table 1 below. The higher the value of Td 5 , the higher the chemical heat resistance (thermal stability), indicating that the generation of volatile organic compounds can be suppressed to a higher temperature.

[0083] (Dielectric properties in the high-frequency band) A test piece with a sample size of 60 mm × 60 mm was prepared using the polyimide film. Using this test piece, the relative permittivity (Dk) and dielectric tangent (Df) at 10 GHz were measured at an ambient temperature of 25 °C using a vector network analyzer MS46122B (manufactured by Anritsu Corporation) and a split cylinder resonator (manufactured by AET Corporation, TE mode). The measurement results are shown in Table 1 below. The lower the values of Dk and Df, the better the dielectric properties.

[0084]

Table 1

Claims

1. A polyimide precursor which is a reaction product of a tetracarboxylic dianhydride having an indane skeleton and a diamine.

2. The polyimide precursor according to Claim 1, having a weight average molecular weight of 2,000 or more and 100,000 or less.

3. A resin composition containing the polyimide precursor according to Claim 1.

4. The resin composition according to Claim 3, further containing an organic solvent.

5. A polyimide molded article which is a cured product of the polyimide precursor according to Claim 1 or 2.

6. A polyimide molded article which is a cured product of the resin composition according to Claim 3 or 4.

7. A method for producing a polyimide molded article, comprising a step of applying and drying the resin composition according to Claim 3 or 4 on a substrate to form a resin film, and a step of heat-treating the resin film.

8. An electronic component comprising an insulating film including the polyimide molded article according to Claim 6.

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