JP2006131662A - Polyimide resin composition and polyimide film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyimide resin composition excellent in dimensional stability by lowering the coefficient of thermal expansion while retaining the transparency. <P>SOLUTION: The polyimide resin composition, which is obtained by the reaction of an acid anhydride and a diamine, contains, as the above acid anhydride, ≥2 kinds of acid anhydrides consisting of 3,3',4,4'-oxydiphthalic acid anhydride and 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride and/or 3,3',4,4'-biphenyltetracarboxylic acid dihydride, and, as the above diamine, diamine(s) selected from ≥1 kinds of 4,4-diamino-dicyclohexylmethane, 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane and 1,4-bis(3-aminopropyl)piperazine. In the composition the content of 3,3',4,4'-oxydiphthalic acid anhydride is 20-40 mol% based on the total content of the above acid anhydride plus the above diamine. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyimide resin composition and a polyimide film used for optical members (liquid crystal display, organic EL display, etc.) such as a film substrate and a protective film, and in particular, a polyimide resin excellent in dimensional stability while maintaining transparency. The present invention relates to a composition and a polyimide film.

  With the progress of the advanced information society, the technological progress of semiconductor devices, optical communication devices, and display devices used in information transmission devices has been remarkable, and research and development in the related optoelectronics field has been actively conducted accordingly. As an optical material that supports these, polymer materials can satisfy the needs of devices and devices such as weight reduction, miniaturization, and flexibility compared to inorganic materials such as glass. Application is progressing in various fields such as members for display devices such as displays), optical disks, and waveguides.

  Examples of the transparent plastic material for optical use include polycarbonate (PC), polymethyl methacrylate (PMMA), transparent ABS resin, polyethersulfone (PES), PET, and the like. In many cases, the above-mentioned materials are insufficient in heat resistance. Therefore, attention is focused on polyimide having excellent heat resistance.

  However, general-purpose polyimides often used for electronic circuit substrates, for example, polyimide resins synthesized from pyromellitic dianhydride and 4,4′-diaminodiphenyl ether, and 3,3 ′, 4,4 ′ Aromatic polyimides typified by polyimide resins and the like synthesized from biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether usually do not have colorless transparency.

  A general method for imparting transparency to polyimide includes a method of introducing an aliphatic material, a fluorine-based material, or the like into the polyimide skeleton. For example, in Patent Document 1, 3,3 ′, 4,4′oxydiphthalic anhydride, hexahydropyromellitic anhydride, etc. are introduced into the alicyclic tetracarboxylic anhydride component, and a siloxane-containing diamine is introduced into the diamine component. By using this, a transparent polyimide is obtained. In Patent Documents 2 and 3, transparent polyimides to be applied to transparent films, liquid crystal alignment films and the like are obtained using 3,3 ', 4,4'oxydiphthalic anhydride and aliphatic diamines.

JP 2003-155342 A JP 2003-176354 A JP 2003-176356 A JP 2002-212288 A

  However, these transparent polyimides usually have a large thermal expansion coefficient (linear expansion coefficient) and are inferior in dimensional stability. For this reason, when a wiring pattern, a vapor deposition layer, etc. are formed on a film after film production, for example, problems, such as a crack and peeling, may occur. A polyimide that suppresses an increase in the coefficient of thermal expansion and is excellent in dimensional stability while maintaining colorless transparency has not been found.

  Then, the objective of this invention is providing the polyimide resin composition and polyimide film which were excellent in dimensional stability by reducing a thermal expansion coefficient, maintaining transparency.

  The present invention has been devised to achieve the above object, and the invention of claim 1 is a polyimide resin composition obtained by the reaction of an acid anhydride and a diamine, wherein the acid anhydride is represented by the chemical formula (1) Diamine selected from one or more of chemical formula (4), chemical formula (5), and chemical formula (6) as the diamine, including two or more acid anhydrides of chemical formula (2) and / or chemical formula (3) And a content of the chemical formula (1) is 20 to 40 mol% of the total content of the acid anhydride and the diamine.

  The invention of claim 2 is the polyimide resin composition obtained by the reaction of an acid anhydride and a diamine, wherein the acid anhydride comprises two or more kinds of chemical formulas (1) and (2) and / or chemical formula (3). An acid anhydride is included, and the diamine includes a diamine selected from one or more of chemical formula (4), chemical formula (5), and chemical formula (6), and the content of chemical formula (1) is the above acid anhydride and the above Polyimide resin composition having a total content of diamine of 20 to 40 mol%, and having a linear expansion coefficient of 30 to 60 ppm / K when the polyimide resin composition is a film having a thickness of 100 ± 5 μm It is a resin composition.

  The invention according to claim 3 is the polyimide resin composition according to claim 1 or 2, wherein the polyimide resin composition has a polystyrene equivalent weight average molecular weight of 20,000 to 200,000.

  In the polyimide film produced using the polyimide resin composition obtained by reaction of an acid anhydride and a diamine, the chemical formula (1), the chemical formula (2) and / or the chemical formula (3) The diamine contains a diamine selected from one or more of the chemical formula (4), the chemical formula (5), and the chemical formula (6), and the content of the chemical formula (1). Is a polyimide film prepared using a polyimide resin composition that is 20 to 40 mol% of the total content of the acid anhydride and the diamine.

  The invention according to claim 5 is the polyimide film according to claim 4, wherein the film thickness is 100 ± 5 μm, the linear expansion coefficient is 30 to 60 ppm / K, and the total light transmittance is 90% or more.

  The invention according to claim 6 is the polyimide film according to claim 4 or 5, wherein the polyimide resin composition has a polystyrene equivalent weight average molecular weight of 20,000 to 200,000.

  ADVANTAGE OF THE INVENTION According to this invention, the polyimide film excellent in dimensional stability can be provided, maintaining transparency.

  Hereinafter, preferred embodiments of the present invention will be described.

The polyimide resin composition according to the present embodiment is a polyimide resin composition obtained by a reaction between an acid anhydride and a diamine,
As an acid anhydride (acid component), 3,3 ′, 4,4 ′ oxydiphthalic anhydride (ODPA) represented by the chemical formula (1) and 3,3 ′, 4,4 represented by the chemical formula (2) 'Two or more aromatic components comprising benzophenonetetracarboxylic dianhydride (BTDA) and / or 3,3', 4,4'biphenyltetracarboxylic dianhydride (BPDA) represented by chemical formula (3) A tetracarboxylic dianhydride that is
As diamine (diamine component), 4,4-diamino-dicyclohexylmethane (DAHM) represented by the chemical formula (4), 3,3′-dimethyl-4,4′-diamino-dicyclohexyl represented by the chemical formula (5) Including an aliphatic diamine having a cyclic structure selected from one or more of methane (DMHM) and 1,4-bis (3-aminopropyl) piperazine (BAPZ) represented by the chemical formula (6);
The content of ODPA represented by the chemical formula (1) is 20 to 40, preferably 25 to 37.5 mol% of the total content of acid anhydride and diamine.

  The reason why the aromatic component represented by the chemical formula (1), the chemical formula (2), or the chemical formula (3) is included as the acid component is that the aliphatic component (for example, 1,2,3,4-cyclopentane, for example) When tetracarboxylic dianhydride (CPDA) or the like is used, as will be described later in (Comparative Example 6), although transparency is obtained, the coefficient of thermal expansion is high and a desired low coefficient of thermal expansion cannot be obtained. Because.

  The reason for including two or more acid components is that when the acid component is one component, the solubility of the polyimide varnish (varnish) is poor, as will be described later in (Comparative Example 1) and (Comparative Example 2). This is because problems such as the reaction of diamine with diamine do not proceed. However, as in this embodiment, by synthesizing polyimide by a two-step reaction including two or more types of acid components and limiting the content of ODPA, the transparency and low thermal expansibility are maintained and good. A varnish capable of producing a polyimide film can be obtained.

  Here, as will be described later in Examples 1 to 7, the two-step reaction does not react all acid anhydrides and all diamines at once, but reacts a certain acid anhydride and diamine one-on-one. And then reacting another acid anhydride and diamine on a one-to-one basis.

  The reason why the content of ODPA is 20 to 40 mol% of the total content of acid anhydride and diamine will be described. Among the acid components, ODPA has a high effect on the expression of transparency, but has a problem that the thermal expansion coefficient becomes high. On the other hand, the use of BTDA and BPDA reduces the thermal expansion coefficient, but has a problem of poor transparency. Therefore, by using ODPA in combination with BTDA and / or BPDA, the thermal expansion coefficient can be lowered while maintaining transparency.

  When the content of ODPA is more than 40 mol% of the total content of acid anhydride and diamine, as will be described later in (Comparative Example 7), the coefficient of thermal expansion increases, and the content of ODPA is When it is less than 20 mol% of the total content of diamine, the transparency is lowered as described later in (Comparative Example 5). Therefore, in order to satisfy both the high transparency and low thermal expansion properties of the polyimide resin composition and the polyimide film, the content of ODPA is set in the range of 20 to 40 mol% of the total content of acid anhydride and diamine.

  In this embodiment, an example of using BTDA or BPDA as an acid anhydride that exhibits low thermal expansibility will be described. Instead of BTDA or BPDA, a tetracarboxylic acid diester that exhibits low thermal expansibility equivalent to BTDA or BPDA is used. Anhydrides may be used.

The polyimide resin composition preferably has a linear expansion coefficient α of 30 to 60 ppm / K (× 10 ⁻⁶ / K) when the above-described polyimide resin composition is a film having a thickness of 100 ± 5 μm.

  As a polyimide resin composition, the polystyrene conversion weight average molecular weight Mw of the polyimide resin composition mentioned above is good in it being 20000-200000.

  Here, the reason why the weight average molecular weight Mw was calculated in terms of polystyrene is that polystyrene conversion is a measurement condition in a general molecular weight measuring apparatus, and the calibration curve of the molecular weight measuring apparatus is prepared using a standard sample of polystyrene. It is.

  The reason why the molecular weight Mw is set to 20000 to 200000 will be described. When molding a polyimide film from a varnish, it is necessary to adjust the molecular weight of the polyimide. When the molecular weight Mw is as low as less than 20000, as will be described later in (Comparative Example 3), the film is cracked and cannot be molded as a film. On the other hand, when the molecular weight Mw is higher than 200000, as will be described later in (Comparative Example 4), the varnish viscosity becomes high and it becomes difficult to cast the varnish on the substrate. In order to obtain a good film, the molecular weight Mw is set in the range of 20000 to 200000.

  Moreover, a polyimide film is obtained by producing a film body using the polyimide resin composition according to the present embodiment.

  As a polyimide film, when the film thickness is 100 ± 5 μm, the linear expansion coefficient is 30 to 60 ppm / K, and the total light transmittance T is preferably 90% or more.

  As a polyimide resin composition for producing a polyimide film, it is good in the weight average molecular weight Mw of polystyrene conversion being 20000-200000.

  The operation of the present embodiment will be described.

  The polyimide resin composition according to the present embodiment includes ODPA, which is a component that exhibits transparency as an acid component, and BTDA and / or BPDA, which is a component that exhibits low thermal expansion, and a diamine having a cyclic structure as a diamine component. And the content of ODPA is 20 to 40 mol% of the total content of acid anhydride and diamine.

  Thereby, in a transparent polyimide resin composition with almost no coloring, the thermal expansion coefficient can be lowered while maintaining transparency.

  Therefore, by forming a film body using the polyimide resin composition according to the present embodiment, the film body has a low thermal expansion coefficient while maintaining transparency (for example, when the film thickness is 100 ± 5 μm, the linear expansion coefficient is Is 30 to 60 ppm / K, and the total light transmittance T is 90% or more.) A polyimide film having excellent dimensional stability can be produced.

  By using this polyimide film, various structures such as wiring patterns and vapor deposition films formed on it have defects such as peeling, cracking, and dropping even after undergoing a thermal process during the manufacturing and assembly process. It is possible to perform the required function.

  The polyimide resin composition and the polyimide film according to the present embodiment are particularly useful in the field of display devices such as liquid crystal displays (for example, liquid crystal alignment films) and organic EL displays that require heat-resistant transparency.

(Example 1) (Content of ODPA with respect to total content of acid anhydride and diamine: 25 mol%)
A condenser tube with a ball equipped with a trap with a silicon cock was attached to a 500 mL four-neck separable flask equipped with a stirrer. Into the flask, 8.83 g (30 mM) of BPDA, 4.77 g (20 mM) of DMHM were added, 0.68 g of γ-caprolactone, 0.95 g of pyridine, 100 g of N-methyl-2-pyrrolidone (NMP), and 20 g of toluene. added. After stirring for 15 minutes in a nitrogen atmosphere, the flask was immersed in an oil bath heated to 180 ° C. and stirred for 1 hour.

  Then, after removing the flask from the oil bath and allowing it to cool to room temperature, 9.31 g (30 mM) of ODPA, 9.54 g (40 mM) of DMHM, 71.6 g of NMP, and 14.3 g of toluene were added. Thereafter, the temperature was raised again to 180 ° C., followed by stirring for 3 hours to obtain a varnish. At this time, water generated during the reaction was appropriately removed from the silicon cock.

The weight average molecular weight Mw in terms of polystyrene of the obtained resin solution was measured using a GPC (gel permeation chromatographic analysis) apparatus, and it was about 70,000. Moreover, the varnish was apply | coated using the applicator on the glass substrate, it dried with the thermostat, and the solvent was removed. When the film was peeled off from the glass substrate and the infrared absorption spectrum of the obtained film was measured, characteristic absorption of the imide ring was observed at wave numbers of 1715 cm ⁻¹ and 1785 cm ⁻¹ .

  The synthesized varnish was put into methanol and reprecipitated, and the precipitated resin was washed with methanol 5 times using a glass filter. Methanol was removed from the washed resin by drying under reduced pressure to obtain a polyimide resin powder. This resin powder was redissolved in N, N-dimethylacetamide to prepare a polyimide varnish having a solid content of 25% by weight. A polyimide film having a thickness of about 100 μm was produced by casting using this varnish. The total light transmittance T of this film was measured and found to be 90.2%. The thermal expansion coefficient α was 41 ppm / K (normal temperature to 150 ° C.).

(Example 2) (Content of ODPA with respect to total content of acid anhydride and diamine: 37.5 mol%)
Using the same apparatus as in Example 1, put 18.61 g (60 mM) of ODPA and 9.54 g (40 mM) of DMHM in the flask, add 0.91 g of γ-caprolactone, 1.27 g of pyridine, 100 g of NMP, and 20 g of toluene. It was.

  In the same manner as in Example 1, the mixture was heated and stirred at 180 ° C. for 1 hour, then cooled to room temperature, and 6.44 g (20 mM) of BTDA and 9.54 g (40 mM) of DMHM were added, and 65.0 g of NMP and 13.0 g of toluene were added. added. The mixture was reheated to 180 ° C. and reacted for 3 hours. When the weight average molecular weight Mw of the obtained polyimide varnish was measured, it was about 120,000.

  A polyimide resin powder was prepared in the same manner as in Example 1, and redissolved in N, N-dimethylacetamide to obtain a varnish. A polyimide film having a thickness of about 100 μm was produced using this varnish. When the total light transmittance T of this film was measured, it was 90.8%, and thermal expansion coefficient (alpha) obtained 52 ppm / K (normal temperature-150 degreeC).

(Example 3) (Content of ODPA with respect to total content of acid anhydride and diamine: 37.5 mol%)
Using the same apparatus as in Example 1, put 18.61 g (60 mM) of ODPA and 9.54 g (40 mM) of DMHM in the flask, add 0.91 g of γ-caprolactone, 1.27 g of pyridine, 100 g of NMP, and 20 g of toluene. It was.

  In the same manner as in Example 1, the mixture was heated and stirred at 180 ° C. for 1 hour, then cooled to room temperature, 5.88 g (20 mM) of BPDA and 9.54 g (40 mM) of DMHM were added, 62.8 g of NMP, and 12.6 g of toluene were added. added. The mixture was reheated to 180 ° C. and reacted for 3 hours. When the weight average molecular weight Mw of the obtained polyimide varnish was measured, it was about 80,000.

  A polyimide resin powder was prepared in the same manner as in Example 1, and redissolved in N, N-dimethylacetamide to obtain a varnish. A polyimide film having a thickness of about 100 μm was produced using this varnish. When the total light transmittance T of this film was measured, it was 90.5%, and the thermal expansion coefficient α was 45 ppm / K (normal temperature to 150 ° C.).

(Example 4) (Content of ODPA with respect to total content of acid anhydride and diamine: 25 mol%)
Using the same apparatus as in Example 1, 8.83 g (30 mM) of BPDA and 4.77 g (20 mM) of DMHM were placed in a flask, and 0.68 g of γ-caprolactone, 0.95 g of pyridine, 100 g of NMP, and 20 g of toluene were added. It was.

  In the same manner as in Example 1, the mixture was heated and stirred at 180 ° C. for 1 hour, and then cooled to room temperature. 9.31 g (30 mM) of ODPA, 9.54 g (40 mM) of DMHM were added, 71.6 g of NMP, and 14.3 g of toluene were added. added. The mixture was reheated to 180 ° C. and reacted for 5 hours. When the weight average molecular weight Mw of the obtained polyimide varnish was measured, it was about 160,000.

  A polyimide resin powder was prepared in the same manner as in Example 1, redissolved in N, N-dimethylacetamide, and a polyimide film having a thickness of about 100 μm was prepared using varnish. When the total light transmittance T of this film was measured, it was 90.1%, and the thermal expansion coefficient α was 36 ppm / K (normal temperature to 150 ° C.).

(Example 5) (Content of ODPA with respect to total content of acid anhydride and diamine: 37.5 mol%)
Using the same apparatus as in Example 1, put 18.61 g (60 mM) of ODPA and 8.41 g (40 mM) of DAHM in the flask, add 0.91 g of γ-caprolactone, 1.27 g of pyridine, 100 g of NMP, and 20 g of toluene. It was.

  In the same manner as in Example 1, the mixture was heated and stirred at 180 ° C. for 1 hour, then cooled to room temperature, and 6.44 g (20 mM) of BTDA and 8.41 g (40 mM) of DAHM were added, and 56.0 g of NMP and 11.2 g of toluene were added. added. The mixture was reheated to 180 ° C. and reacted for 3 hours. When the weight average molecular weight Mw of the obtained polyimide varnish was measured, it was about 100,000.

  A polyimide resin powder was prepared in the same manner as in Example 1, and redissolved in N, N-dimethylacetamide to obtain a varnish. A film having a thickness of about 100 μm was prepared using this varnish. When the total light transmittance T of this film was measured, it was 91.0%, and thermal expansion coefficient (alpha) obtained 55 ppm / K (normal temperature-150 degreeC).

(Example 6) (Content of ODPA with respect to total content of acid anhydride and diamine: 37.5 mol%)
Using the same apparatus as in Example 1, put 18.61 g (60 mM) of ODPA and 8.41 g (40 mM) of DAHM in the flask, add 0.91 g of γ-caprolactone, 1.27 g of pyridine, 100 g of NMP, and 20 g of toluene. It was.

  These were heated and stirred at 180 ° C. for 1 hour, and then cooled to room temperature. Next, 5.88 g (20 mM) of BPDA and 8.41 g (40 mM) of DAHM were added, and 53.7 g of NMP and 10.7 g of toluene were added. The mixture was reheated to 180 ° C. and reacted for 3 hours. When the weight average molecular weight Mw of the obtained polyimide varnish was measured, it was about 80,000.

  A polyimide resin powder was prepared in the same manner as in Example 1, and redissolved in N, N-dimethylacetamide to obtain a varnish. A film having a thickness of about 100 μm was prepared using this varnish. When the total light transmittance T of this film was measured, it was 91.5%, and the thermal expansion coefficient α was 50 ppm / K (from room temperature to 150 ° C.).

(Example 7) (Content of ODPA with respect to total content of acid anhydride and diamine: 25 mol%) (1 / 2BPDA + 1/2 ODPA + BAPZ)
Using the same apparatus as in Example 1, 8.83 g (30 mM) of BPDA and 4.01 g (20 mM) of BAPZ were placed in a flask, and 0.68 g of γ-caprolactone, 0.95 g of pyridine, 100 g of NMP, and 20 g of toluene were added. It was.

  This was heated and stirred at 180 ° C. for 1 hour, and then returned to room temperature. 9.31 g (30 mM) of ODPA and 8.01 g (40 mM) of BAPZ were added, and 40.0 g of NMP and 8.0 g of toluene were added. The mixture was reheated to 180 ° C. and reacted for 10 hours. When the weight average molecular weight Mw of the obtained polyimide varnish was measured, it was about 100,000.

  A polyimide resin powder was prepared in the same manner as in Example 1, and redissolved in N, N-dimethylacetamide to prepare a film having a thickness of about 100 μm using varnish, and the total light transmittance T was measured. 1% and thermal expansion coefficient (alpha) obtained 55 ppm / K (normal temperature-150 degreeC).

(Comparative Example 1) (Content of ODPA with respect to total content of acid anhydride and diamine: 0 mol%)
Using the same apparatus as in Example 1, 8.83 g (30 mM) of BPDA and 4.47 g (20 mM) of DMHM were placed in a flask, and 0.68 g of γ-caprolactone, 0.95 g of pyridine, 100 g of NMP, and 20 g of toluene were added. It was.

  After stirring for 15 minutes in a nitrogen atmosphere, the mixture was heated to 180 ° C. and stirred for 1 hour. After cooling to room temperature, 8.83 g (30 mM) of BPDA and 9.54 g (40 mM) of DMHM were added, and 68.9 g of NMP and 13.8 g of toluene were added. It was reheated to 180 ° C. and reacted for 3 hours to obtain a polyimide varnish having a weight average molecular weight Mw of about 60,000.

  As in Example 1, the varnish was reprecipitated in methanol to prepare a polyimide resin powder, which was re-dissolved in N, N-dimethylacetamide to prepare a varnish, but the viscosity of the varnish increased and solidified within one day. Therefore, film production was not achieved.

  When it was redissolved in NMP as a reaction solvent to produce a varnish and formed into a film, it became a film with irregularities on the surface, causing problems in film formability, and coloring was observed on the film. The NMP solvent varnish also solidified within one month and had a problem in storage stability.

(Comparative example 2) (Content of ODPA with respect to total content of acid anhydride and diamine: 0 mol%)
Using the same apparatus as in Example 1, 19.33 g (60 mM) of BTDA and 14.31 g (60 mM) of DMHM were put in a flask, 0.61 g of γ-caprolactone, 0.95 g of pyridine, 125.9 g of NMP, toluene 25 .2 g was added. These were heated and stirred at 180 ° C. for reaction. As a result, turbidity was generated in the reaction solution, and a normal varnish could not be obtained. (Comparative Example 3) (ODPA content: 25 mol% relative to the total content of acid anhydride and diamine)
Using the same apparatus as in Example 1, 8.83 g (30 mM) of BPDA and 4.47 g (20 mM) of DMHM as an aliphatic diamine were placed in a flask, 0.68 g of γ-caprolactone, 0.95 g of pyridine, 100 g of NMP, Toluene 20g was added.

  In the same manner as in Example 1, the mixture was heated and stirred at 180 ° C. for 1 hour, and then cooled to room temperature. 9.31 g (30 mM) of ODPA, 9.54 g (40 mM) of DMHM were added, 71.6 g of NMP, and 14.3 g of toluene were added. added. It was reheated to 180 ° C. and reacted for 45 minutes to obtain a polyimide varnish having a weight average molecular weight Mw of about 10,000. The varnish was reprecipitated in methanol to produce a polyimide resin powder, which was redissolved in N, N-dimethylacetamide to obtain a varnish. Film production was attempted using this varnish, but when the film was peeled off from the substrate, it was cracked and cut, and could not be produced into a film having sufficient strength.

(Comparative Example 4) (Content of ODPA with respect to total content of acid anhydride and diamine: 25 mol%)
Using the same apparatus as in Example 1, 8.83 g (30 mM) of BPDA and 4.47 g (20 mM) of DMHM as an aliphatic diamine were placed in a flask, 0.68 g of γ-caprolactone, 0.95 g of pyridine, 100 g of NMP, Toluene 20g was added.

  In the same manner as in Example 1, the mixture was heated and stirred at 180 ° C. for 1 hour, and then cooled to room temperature. 9.31 g (30 mM) of ODPA, 9.54 g (40 mM) of DMHM were added, 71.6 g of NMP, and 14.3 g of toluene were added. added. The reaction was reheated to 180 ° C. In the reaction time of about 10 hours, the increase in the viscosity exceeded the allowable torque value of the stirrer, and stirring became impossible. When the molecular weight of the varnish was measured, the weight average molecular weight Mw was about 250,000. This high-viscosity polyimide varnish was reprecipitated in methanol using a high-speed stirrer, and a polyimide resin powder was produced in the same manner as in Example 1. This resin powder was redissolved in N, N-dimethylacetamide to obtain a varnish. An attempt was made to produce a film using a varnish having a resin concentration of 20% by weight, but the viscosity was high and it was difficult to cast the varnish to a substrate, and a uniform film could not be obtained.

(Comparative Example 5) (ODPA content: 12.5 mol% relative to the total content of acid anhydride and diamine)
Using the same apparatus as in Example 1, 17.65 g (60 mM) of BPDA and 9.54 g (40 mM) of DMHM were placed in a flask, and 0.91 g of γ-caprolactone, 1.27 g of pyridine, 100 g of NMP, and 20 g of toluene were added. It was.

  In the same manner as in Example 1, the mixture was heated and stirred at 180 ° C. for 1 hour, then cooled to room temperature, and 6.20 g (20 mM) of ODPA and 9.54 g (40 mM) of DMHM were added, and 59.8 g of NMP and 12.0 g of toluene were added. added. The mixture was reheated to 180 ° C. and reacted for 5 hours. When the weight average molecular weight Mw of the obtained polyimide varnish was measured, it was about 100,000.

  A polyimide resin powder was prepared, dissolved in N, N-dimethylacetamide, and a film having a thickness of about 100 μm was prepared using varnish. When the total light transmittance T of this film was measured, it was 88%, and thermal expansion coefficient (alpha) obtained 43 ppm / K (normal temperature-150 degreeC).

(Comparative Example 6) (Content of ODPA with respect to total content of acid anhydride and diamine: 0 mol%)
Using the same apparatus as in Example 1, 12.61 g (60 mM) of CPDA and 14.31 g (60 mM) of DMHM were placed in a flask, 0.61 g of γ-caprolactone, 0.95 g of pyridine, 99.0 g of NMP, toluene 19 .8 g was added. These were reacted by heating and stirring at 180 ° C. for 30 hours. When the weight average molecular weight Mw of the obtained polyimide varnish was measured, it was about 70,000.

  A polyimide resin powder was prepared in the same manner as in Example 1, and redissolved in N, N-dimethylacetamide to obtain a varnish. A film having a thickness of about 100 μm was prepared using this varnish. When the total light transmittance T of this film was measured, it was 91.5%, and the thermal expansion coefficient α was 75 ppm / K (normal temperature to 150 ° C.).

(Comparative Example 7) (Content of ODPA with respect to total content of acid anhydride and diamine: 45 mol%)
Using the same apparatus as in Example 1, 18.61 g (60 mM) of ODPA and 8.41 g (40 mM) of DAHM were placed in a flask, 0.91 g of γ-caprolactone, 1.27 g of pyridine, 100.0 g of NMP, toluene 20 0.0 g was added.

  These were heated and stirred at 180 ° C. for 1 hour, and then cooled to room temperature. Next, 2.35 g (8 mM) of BPDA, 3.72 g (12 mM) of ODPA, and 8.41 g (40 mM) of DAHM were added, and 54.5 g of NMP and 10.9 g of toluene were added. The mixture was reheated to 180 ° C. and reacted for 3 hours. When the weight average molecular weight Mw of the obtained polyimide varnish was measured, it was about 80,000.

  A polyimide resin powder was prepared in the same manner as in Example 1, and redissolved in N, N-dimethylacetamide to obtain a varnish. A film having a thickness of about 100 μm was prepared using this varnish. When the total light transmittance T of this film was measured, it was 91.1%, and the thermal expansion coefficient α was 63 ppm / K (normal temperature to 150 ° C.).

(Comparative Example 8) (Content of ODPA with respect to total content of acid anhydride and diamine: 50 mol%) (OPDA + DAHM)
Using the same apparatus as in Example 1, 23.54 g (80 mM) of ODPA and 16.82 g (80 mM) of DMHM were placed in a flask, 0.91 g of γ-caprolactone, 1.27 g of pyridine, 149.9 g of NMP, 30 toluene. 0.0 g was added. After stirring for 15 minutes in a nitrogen atmosphere, the mixture was heated to 180 ° C. and stirred for 7 hours to be reacted. A polyimide varnish having a weight average molecular weight of about 60,000 was obtained.

A polyimide resin powder was prepared in the same manner as in Example 1, and redissolved in N, N-dimethylacetamide to obtain a varnish. Using this varnish, a film having a thickness of about 100 μm was prepared, and the total light transmittance T of this film was measured. .

Claims (6)

In the polyimide resin composition obtained by the reaction of an acid anhydride and a diamine, the acid anhydride includes two or more kinds of acid anhydrides composed of the chemical formula (1) and the chemical formula (2) and / or the chemical formula (3), The diamine includes a diamine selected from one or more of the chemical formula (4), the chemical formula (5), and the chemical formula (6), and the content of the chemical formula (1) is 20 of the total content of the acid anhydride and the diamine. A polyimide resin composition, characterized in that it is -40 mol%.

  In the polyimide resin composition obtained by the reaction of an acid anhydride and a diamine, the acid anhydride includes two or more kinds of acid anhydrides composed of the chemical formula (1) and the chemical formula (2) and / or the chemical formula (3), The diamine includes a diamine selected from one or more of the chemical formula (4), the chemical formula (5), and the chemical formula (6), and the content of the chemical formula (1) is 20 of the total content of the acid anhydride and the diamine. A polyimide resin composition having a molecular expansion coefficient of 30 to 60 ppm / K when the polyimide resin composition is a film having a thickness of 100 ± 5 μm. object.   The polyimide resin composition according to claim 1 or 2, wherein the polyimide resin composition has a polystyrene-equivalent weight average molecular weight of 20,000 to 200,000.   In the polyimide film produced using the polyimide resin composition obtained by reaction of an acid anhydride and a diamine, two or more kinds of chemical formula (1) and chemical formula (2) and / or chemical formula (3) are used as the acid anhydride. An acid anhydride is included, and the diamine includes a diamine selected from one or more of chemical formula (4), chemical formula (5), and chemical formula (6), and the content of chemical formula (1) is the above acid anhydride and the above A polyimide film produced using a polyimide resin composition having a total content of diamine of 20 to 40 mol%.   5. The polyimide film according to claim 4, wherein when the film thickness is 100 ± 5 μm, the linear expansion coefficient is 30 to 60 ppm / K, and the total light transmittance is 90% or more. The polyimide film according to claim 4 or 5, wherein the polyimide resin composition has a polystyrene-equivalent weight average molecular weight of 20,000 to 200,000.