Polyimide composition

Abstract

To provide a polyimide composition having excellent dielectric properties, mechanical properties and solvent solubility.SOLUTION: There is provided a polyimide composition obtained by subjecting a polyamic acid composition obtained by polymerizing a diamine component composed of 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,spirobiindane and 4,4'-diaminodiphenyl ether and an acid component composed of 3,3',4,4'-biphenyltetracarboxylic dianhydride to a cyclization reaction, wherein the content of the 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane in the diamine component is 25.0 mol% or more and less than 50.0 mol% and the content of the 4,4'-diaminodiphenyl ether is more than 50.0 mol% and 75.0 mol% or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polyimide composition.

Background Art

[0002] Polyimide compositions are excellent not only in heat resistance but also in properties such as chemical resistance, radiation resistance, electrical insulation, and mechanical properties. For this reason, polyimide compositions are currently widely used in various electronic devices as materials for substrates for flexible printed wiring circuits, base materials for tape automated bonding, protective films for semiconductor elements, interlayer insulating films for integrated circuits, and the like. In addition, in high-functional electronic devices developed in recent years, polyimide compositions are required to be excellent not only in dielectric properties and mechanical properties but also in solvent solubility.

[0003] As a polyimide composition that has been widely used conventionally, for example, Patent Document 1 discloses a polyimide composition obtained by polymerizing an aromatic diamine component having a predetermined molar ratio of 4,4'-diaminodiphenyl ether (hereinafter also referred to as "ODA") and p-phenylenediamine (also referred to as "PDA") and 3,3',4,4'-biphenyltetracarboxylic dianhydride (hereinafter also referred to as "BPDA").

[0004] In addition, Patent Documents 2 and 3 disclose polyimide compositions using 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane (hereinafter also referred to as "SPI-AN") as a raw material.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] However, the polyimide composition of Patent Document 1 has a high relative dielectric constant of about 3.5 and is hardly soluble in organic solvents, which is disadvantageous for applications in high-performance electronic devices developed in recent years. Further, the polyimide compositions of Patent Documents 2 and 3 have an insufficient balance between dielectric properties and mechanical properties, and there is room for improvement for use in high-performance electronic device applications.

[0007] In view of the above problems, an object of the present invention is to provide a polyimide composition excellent in dielectric properties, mechanical properties, and solvent solubility.

MEANS FOR SOLVING THE PROBLEMS

[0008] As a result of intensive studies to solve the above problems, the present inventors have obtained the following findings. By subjecting a polyamic acid composition obtained by polymerizing a diamine component having SPI-AN and ODA in a predetermined molar ratio and an acid component composed of BPDA to a cyclization reaction, a polyimide composition having excellent dielectric properties, mechanical properties, and solvent solubility can be obtained.

[0009] That is, the gist configuration of the present invention is as follows.

[0010] [1] A polyimide composition obtained by subjecting a polyamic acid composition obtained by polymerizing a diamine component composed of 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane and 4,4'-diaminodiphenyl ether and an acid component composed of 3,3',4,4'-biphenyltetracarboxylic dianhydride to a cyclization reaction, The polyimide composition is characterized in that the content of 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane in the diamine component is 25.0 mol% or more and less than 50.0 mol%, and the content of 4,4'-diaminodiphenyl ether is more than 50.0 mol% and 75.0 mol% or less.

[0011] [2] The relative permittivity at a frequency of 10 GHz is 3.20 or less, the dielectric loss tangent at a frequency of 10 GHz is 0.0060 or less, the breaking strength is 95 MPa or more, the elastic modulus is 2.0 GPa or more, The polyimide composition according to [1] above.

Effect of the Invention

[0012] According to the present invention, a polyimide composition excellent in dielectric properties, mechanical properties, and solvent solubility can be provided.

Mode for Carrying Out the Invention

[0013] Hereinafter, a polyimide composition according to an embodiment of the present invention will be described. The embodiment described below is an example embodying the present invention, and does not limit the configuration of the present invention with its specific examples.

[0014] [Polyimide Composition] The polyimide composition according to an embodiment of the present invention is a polyimide composition obtained by subjecting a polyamic acid composition obtained by polymerizing a diamine component composed of SPI-AN and ODA and an acid component composed of BPDA to a cyclization reaction. And the content of SPI-AN in the diamine component is 25.0 mol% or more and less than 50.0 mol%, and the content of ODA is more than 50.0 mol% and 75.0 mol% or less. The molar ratio is the molar ratio with all the monomers in the diamine component as 100 mol%. The acid component consists of 100 mol% of BPDA.

[0015] 6,6'-Bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane (SPI-AN) is a compound represented by the following Chemical Formula 1. In the polymerization reaction for producing the polyimide composition, when the content of SPI-AN in the diamine component is less than 25.0 mol%, a polyimide composition excellent in dielectric properties and solvent solubility cannot be obtained. Therefore, the content of SPI-AN in the diamine component shall be 25.0 mol% or more. On the other hand, in the polymerization reaction for producing the polyimide composition, when the content of SPI-AN in the diamine component is 50.0 mol% or more, a polyimide composition excellent in mechanical properties cannot be obtained. Therefore, the content of SPI-AN in the diamine component shall be less than 50.0 mol%, preferably 49 mol% or less.

Chem.

[0016] 4,4'-Diaminodiphenyl ether (ODA) is a compound represented by the following Chemical Formula 2. In the polymerization reaction for producing the polyimide composition, when the content of ODA in the diamine component is 50.0 mol% or less, a polyimide composition excellent in mechanical properties cannot be obtained. Therefore, the content of ODA in the diamine component shall exceed 50.0 mol%, preferably 51 mol% or more. On the other hand, in the polymerization reaction for producing the polyimide composition, when the content of ODA in the diamine component exceeds 75.0 mol%, a polyimide composition excellent in dielectric properties and solvent solubility cannot be obtained. Therefore, the content of ODA in the diamine component shall be 75.0 mol% or less.

Chem.

[0017] 3,3',4,4'-Biphenyltetracarboxylic dianhydride (BPDA) is a compound represented by the following Chemical Formula 3. In the polymerization reaction for producing the polyimide composition, the acid component shall consist of BPDA. [Chemistry]

[0018] Next, the preferable dielectric properties, mechanical properties, and solvent solubility of the polyimide composition according to the embodiment of the present invention will be described.

[0019] The polyimide composition preferably has a relative permittivity of 3.20 or less at a frequency of 10 GHz.

[0020] The polyimide composition preferably has a dielectric tangent of 0.0060 or less at a frequency of 10 GHz.

[0021] The relative permittivity and dielectric tangent of the polyimide composition can be measured by the following method. Using a microwave signal generator (manufactured by Hittite Microwave Corporation, HMC-T2220), the relative permittivity and dielectric tangent of the polyimide composition under dry conditions at 10 GHz are measured at room temperature by the cavity resonator method.

[0022] The polyimide composition preferably has a breaking strength of 95 MPa or more.

[0023] The polyimide composition preferably has a modulus of elasticity of 2.0 GPa or more.

[0024] The breaking strength and modulus of elasticity of the polyimide composition can be measured by the following method. Using a tensile testing machine (manufactured by Shimadzu Corporation, Autograph AGS-J), a tensile test (stretching speed: 102 mm / min) is performed on a test piece (10 mm × 70 mm) of the polyimide composition. The modulus of elasticity is obtained from the initial slope of the obtained stress-strain curve, and the breaking strength is determined from the load at which the polyimide composition breaks.

[0025] The polyimide composition preferably has excellent solvent solubility. In particular, the polyimide composition preferably has a solvent solubility in N,N-dimethylacetamide at room temperature of 10 parts by mass or more. By having such excellent solvent solubility, it can be suitably applied to high-performance electronic devices.

[0026] The solvent solubility of the polyimide composition can be measured by the following method. Taking 10 parts by mass of the polyimide composition, add 90 parts by mass of N,N-dimethylacetamide at room temperature. If the polyimide composition completely dissolves in N,N-dimethylacetamide, it is determined that the solvent solubility is excellent; if the polyimide composition does not completely dissolve, it is determined that the solvent solubility is not excellent.

[0027] [Method for producing polyimide composition] The method for producing a polyimide composition according to an embodiment of the present invention includes a step of polymerizing a diamine component composed of SPI-AN and ODA and an acid component composed of BPDA to obtain a polyamic acid composition, and a step of subjecting the polyamic acid composition to a cyclization reaction to obtain a polyimide composition. And the content of SPI-AN in the diamine component is 25.0 mol% or more and less than 50.0 mol%, and the content of ODA is more than 50.0 mol% and 75.0 mol% or less.

[0028] The diamine component used in the production of the polyimide composition is composed of SPI-AN and ODA. The respective contents in the diamine component are as described above. Also, the acid component used in the production of the polyimide composition is composed of BPDA as described above.

[0029] The solvent (polymerization solvent) used in the polymerization reaction only needs to be able to dissolve the diamine component and the acid component which are monomers, and the type thereof is not particularly limited, but a protic solvent is preferred.

[0030] Examples of the polymerization solvent include amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; 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; phenolic solvents such as m-cresol, p-cresol, 3-chlorophenol, and 4-chlorophenol; and it is preferable to use acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide, etc.

[0031] Furthermore, as the polymerization solvent, 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, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, terpene, mineral spirit, petroleum naphtha-based solvents, etc. may be used.

[0032] In the production of the polyimide composition, first, a diamine component and an acid component are polymerized to obtain a polyamic acid composition. The diamine component is dissolved in a polymerization solvent and stirred using a mechanical stirrer. While continuing the stirring, a powder of an acid component in a substantially equimolar amount to the diamine component is gradually added to the polymerization solvent to obtain a solution of the polyamic acid composition (polyamic acid solution). From the viewpoint of promoting the polymerization reaction, the temperature of the solution during stirring is preferably 0 °C or higher, more preferably 5 °C or higher. On the other hand, from the viewpoint of suppressing the coloring of the polyamic acid composition, the temperature of the solution during stirring is preferably 100 °C or lower, more preferably 60 °C or lower. Also, the stirring time (including the time for adding the acid component) is preferably 0.5 hours or longer, more preferably 1 hour or longer, from the viewpoint of causing a uniform reaction. On the other hand, the stirring time is preferably 100 hours or shorter, more preferably 50 hours or shorter, from the viewpoint of preventing the decomposition of the polyamic acid composition and the occurrence of side reactions. The concentration of the monomers (SPI-AN, ODA, and BPDA) in the polymerization solvent (N,N-dimethylacetamide) can be 20 to 30% by mass.

[0033] The polyamic acid solution obtained as described above is applied onto a substrate made of any one of glass, steel, aluminum, silicon, etc., and dried in an oven. By drying the polyamic acid solution, a film-like polyamic acid composition (polyamic acid film) is obtained. From the viewpoint of promoting the volatilization of the solvent, the temperature of the atmosphere during drying is preferably 40 °C or higher, more preferably 50 °C or higher. On the other hand, from the viewpoint of suppressing the coloring of the polyamic acid composition, the temperature of the atmosphere during drying is preferably 220 °C or lower, more preferably 210 °C or lower. Also, the drying may be carried out while changing the temperature of the atmosphere in stages. Note that the drying is preferably carried out in an inert gas atmosphere.

[0034] The obtained polyamic acid film is subjected to a cyclization reaction to obtain a film-like polyimide composition (polyimide film). Examples of the method for causing the cyclization reaction include heating the polyamic acid film on a substrate. In this case, from the viewpoint of sufficiently causing the cyclization reaction, the temperature of the atmosphere during heating is preferably 200°C or higher, more preferably 250°C or higher. On the other hand, from the viewpoint of suppressing coloring or partial thermal decomposition of the obtained polyimide composition, the temperature of the atmosphere during heating is preferably 430°C or lower, more preferably 400°C or lower. The cyclization reaction is preferably carried out in a vacuum or in an inert gas such as nitrogen, but may be carried out in air if the temperature of the atmosphere during heating is not too high (350°C or lower). Further, the heating may be carried out stepwise while changing the temperature of the atmosphere during heating.

[0035] As another embodiment, the cyclization reaction can also be carried out by immersing the polyamic acid film in a solution containing a dehydrating agent such as acetic anhydride in the presence of a tertiary amine such as pyridine or triethylamine.

[0036] Also, as another embodiment, a solution of the polyimide composition (polyimide solution) can be obtained by heating the polyamic acid solution as it is or after appropriately diluting it with a solvent to 150 to 200°C. At this time, toluene, xylene, or the like may be added to the polyimide solution in order to azeotropically distill off water or the like, which is a by-product of the cyclization reaction. Further, a base such as γ-picoline may be added to the polyimide solution as a catalyst.

[0037] The polyimide composition can also be isolated as a powder by dropping the polyimide solution obtained by the above method into a poor solvent such as a large amount of water or methanol and then filtering. A polyimide molded body can be obtained by hot-compressing the powder of the polyimide composition. In this case, from the viewpoint of moldability, the temperature of the polyimide composition during hot-compression is preferably 200°C or higher, more preferably 250°C or higher. On the other hand, from the viewpoint of suppressing coloring of the polyimide composition, the temperature of the polyimide composition during hot-compression is preferably 450°C or lower, more preferably 430°C or lower.

[0038] Furthermore, by redissolving the obtained powder of the polyimide composition in the above-described polymerization solvent, a polyimide solution can be obtained again. By applying the thus-obtained polyimide solution onto a substrate and drying it, a polyimide film can be obtained. From the viewpoint of promoting the volatilization of the solvent, the temperature of the atmosphere during drying is preferably 40°C or higher, more preferably 100°C or higher. On the other hand, from the viewpoint of suppressing the coloring of the polyimide composition, the temperature of the atmosphere during drying is preferably 400°C or lower, more preferably 250°C or lower. Also, the drying may be carried out while changing the temperature of the atmosphere in stages.

[0039] Additives such as an antioxidant, a filler, a silane coupling agent, a photosensitizer, a photopolymerization initiator, and a sensitizer can be added to the polyimide composition and its precursor, the polyamic acid composition, as necessary.

[0040] For processes and conditions not described in this specification, conventional methods can be used.

Examples

[0041] [Example 1] [Preparation of Polyamic Acid Composition] In a well-dried sealed reaction vessel equipped with a stirrer, SPI-AN and ODA as diamine components were dissolved in N,N-dimethylacetamide as a polymerization solvent to obtain a solution. BPDA as an acid component was gradually added to the obtained solution, and a polymerization reaction was carried out while stirring at room temperature for 22 hours using a mechanical stirrer. The concentration of the monomers (SPI-AN, ODA, and BPDA) in the polymerization solvent (N,N-dimethylacetamide) was 20 to 30% by mass. Table 1 shows the addition amounts of SPI-AN, ODA, and BPDA in Example 1, and the molar ratios of the respective components in the diamine component or the acid component. After completion of stirring, a polyamic acid solution as a transparent and viscous polyimide precursor was obtained.

[0042] The obtained polyamic acid solution was applied to a glass substrate and heated and dried in sequence under the conditions of 100 °C (30 minutes), 150 °C (30 minutes), and 200 °C (30 minutes) to obtain a polyamic acid film. The obtained polyamic acid film was flexible and no breakage was observed in the 180° bending test. This indicates that the obtained polyamic acid composition is a polymer with sufficient high molecular weight.

[0043] [Preparation of Polyimide Composition] The obtained polyamic acid film was heat-treated in sequence on the substrate in air under the conditions of 200 °C (10 minutes), 250 °C (30 minutes), and 350 °C (30 minutes) to carry out a cyclization reaction. Thus, a polyimide film with a thickness of about 50 μm was obtained. The obtained polyimide film did not break in the 180° bending test and showed flexibility.

[0044] The dielectric properties (relative permittivity and dielectric loss tangent), mechanical properties (breaking strength and elastic modulus), and solvent solubility of the obtained polyimide film were measured by the methods described above. Also, the thermal properties (Tg, Td 5 , and CTE) were evaluated by the following method. The results are shown in Table 1. Regarding the solvent solubility, when it was excellent in solvent solubility, it was denoted as "+", and when it was not excellent in solvent solubility, it was denoted as "-".

[0045] [Glass Transition Temperature Tg] Dynamic viscoelasticity measurement was carried out using a dynamic viscoelasticity measurement device (DMA Q800 manufactured by TA Instruments). The glass transition temperature Tg (°C) of the polyimide film was determined from the loss peak at a frequency of 0.1 Hz and a heating rate of 5 °C / min.

[0046] [5% Mass Loss Temperature Td 5 Using a thermogravimetric analyzer (DTG-60 manufactured by Shimadzu Corporation), the polyimide film was heated in nitrogen at a heating rate of 10 °C / min. During the heating process, the temperature Td 5 (°C) was measured when the mass of the polyimide film decreased by 5% from the initial mass. Note that the higher the Td 5 , the higher the thermal stability of the polyimide film.

[0047] ​ [Coefficient of Thermal Expansion in the Linear Direction (CTE)] Thermomechanical analysis was performed using a thermomechanical analyzer (manufactured by Shimadzu Corporation, TMA60). The coefficient of thermal expansion in the linear direction (CTE) (ppm / K) of the polyimide film was determined as the average value in the range of 50 to 150°C from the elongation of the polyimide film at a load of 1.6 g per 1 μm of film thickness and a heating rate of 10°C / min.

[0048] <Example 2> A polyimide film was produced and evaluated in the same manner as in Example 1, except that 4.9 mmol of SPI-AN and 5.1 mmol of ODA were used. The obtained polyamic acid film and polyimide film showed flexibility. The evaluation results are as shown in Table 1.

[0049] <Comparative Example 1> A polyimide film was produced and evaluated in the same manner as in Example 1, except that 7.5 mmol of SPI-AN and 2.5 mmol of ODA were used. The obtained polyamic acid film and polyimide film showed flexibility. The evaluation results are as shown in Table 1.

[0050] <Comparative Example 2> An attempt was made to produce a polyamic acid film in the same manner as in Example 1, except that 10 mmol of SPI-AN was used without using ODA. However, the film was not flexible, cracks occurred in the obtained polyamic acid film, and physical property evaluation could not be performed.

[0051] <Comparative Example 3> A polyimide film was produced and evaluated in the same manner as in Example 1, except that 10 mmol of ODA was used without using SPI-AN. The obtained polyamic acid film and polyimide film showed flexibility. The evaluation results are as shown in Table 1.

[0052]

Table 1

[0053] As shown in Table 1, in Examples 1 and 2 where the contents of SPI-AN and ODA in the diamine component were within the scope of the present invention, polyimide compositions excellent in dielectric properties, mechanical properties, and solvent solubility were obtained. On the other hand, in Comparative Examples 1 to 3 where the contents of SPI-AN and ODA in the diamine component were outside the scope of the present invention, the obtained polyimide compositions were inferior in at least one of dielectric properties, mechanical properties, and solvent solubility.

Industrial Applicability

[0054] According to the present invention, a polyimide composition excellent in dielectric properties, mechanical properties, and solvent solubility can be provided. Such a polyimide composition is suitable as a substrate material for high-frequency circuits and can be used for electric insulating films, flexible printed wiring boards, etc. in various electronic devices.

Claims

1. A polyimide composition obtained by subjecting a polyamic acid composition, which is obtained by polymerizing a diamine component comprising 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane and 4,4'-diaminodiphenyl ether and an acid component comprising 3,3',4,4'-biphenyltetracarboxylic dianhydride, to a cyclization reaction, wherein the content of 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane in the diamine component is 25.0 mol% or more and less than 50.0 mol%, and the content of 4,4'-diaminodiphenyl ether is more than 50.0 mol% and 75.0 mol% or less. A polyimide composition characterized by the above.

2. The relative permittivity at a frequency of 10 GHz is 3.20 or less, the dielectric loss tangent at a frequency of 10 GHz is 0.0060 or less, the breaking strength is 95 MPa or more, the elastic modulus is 2.0 GPa or more, The polyimide composition according to Claim 1.

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