JP2016102147A - Polyimide film, substrate using the same and method for producing polyimide film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyimide film that is excellent in optical transparency and heat resistance and has a low linear expansion coefficient at a high temperature and to provide a method for producing the polyimide film.SOLUTION: The polyimide film contains at least one kind of repeating units represented by formula (7) and (8) a cis end-to-end isomer thereof. In the polyimide film, the total amount of repeating units represented by formula (7) and (8) a cis end-to-end isomer thereof is 90 mol% or more based on the total repeating units; the linear expansion coefficient at 350°C is 10 ppm/°C or less; and the average linear expansion coefficient obtained from length change in a temperature range of 50 to 400°C under the condition in a nitrogen atmosphere and at a programming rate of 5°C/min is 15 ppm/°C or less. [Rto Rare each independently H or the like;Ris a 6-40C aryl group; and n is an integer of 0 to 12]SELECTED DRAWING: None

Description

  The present invention relates to a polyimide film, a substrate using the same, and a method for producing a polyimide film. More specifically, the present invention relates to a polyimide film, a flexible wiring substrate, a substrate for transparent electrodes, a substrate for laminating liquid crystal alignment films, and a substrate for organic EL display. , A substrate for organic EL lighting, and a method for producing a polyimide film.

  In recent years, research and development of heat-resistant materials have been actively conducted, and polyimide has attracted attention from the viewpoint of excellent heat resistance and dimensional stability. As such a polyimide, a wholly aromatic polyimide “Kapton”, which is a representative organic material developed in the 1960s by DuPont, USA, for example, has the highest class of heat resistance among heat resistant polymers. It is known that such a wholly aromatic polyimide is a polymer material that can withstand a high temperature of about 300 ° C. and a severe space environment for a long period of time.

  As another wholly aromatic polyimide, for example, JP 2007-46045 A (Patent Document 1) discloses a polyimide film having an average linear expansion coefficient of −20 to 10 ppm / ° C. at 100 to 400 ° C. It is disclosed. In addition, JP 2009-67042 A (Patent Document 2) casts a solvent solution of a polyimide precursor on a support, removes the solvent in the solution and peels from the support as a self-supporting film, A polyimide film obtained by stretching a self-supporting film in the width direction at an initial heating temperature of 80 to 300 ° C and then heating at a final heating temperature of 350 to 580 ° C is disclosed.

  However, such wholly aromatic polyimides exhibit a brown color and require transparency because intramolecular charge transfer (CT) occurs between the aromatic tetracarboxylic dianhydride unit and the aromatic diamine unit. It was not possible to use it for intended applications (printable electronics applications, flexible glass substitute applications, semiconductor resist applications, etc.). Therefore, in recent years, in order to produce a polyimide that can be used for applications requiring transparency, research on alicyclic polyimides that do not cause intramolecular CT and have high light transmittance has been advanced. Thus, alicyclic polyimides that are excellent in light transmittance and heat resistance have been developed.

  As such alicyclic polyimide, for example, in International Publication No. 2014/034760 (Patent Document 3), the following general formulas (I) and (II):

[Wherein, R ^a , R ^b and R ^c each independently represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluorine atom, and R ^d represents 6 carbon atoms. Represents an aryl group of ˜40, and n represents an integer of 0 to 12. ]
Polyimide containing at least one of the repeating units represented by the formula (1) and the total amount of the repeating units represented by the general formulas (1) and (2) being 90 mol% or more based on all repeating units. Is disclosed. Such an alicyclic polyimide described in Patent Document 3 has a sufficiently high light transmittance and heat resistance, and also has a sufficiently low linear expansion coefficient.

JP 2007-46045 A JP 2009-67042 A International Publication No. 2014/034760

  However, even in the alicyclic polyimide having a sufficiently low linear expansion coefficient as described in Patent Document 3, in terms of suppressing increase in the linear expansion coefficient at a high temperature (for example, a temperature of 350 ° C. or higher), it is not always necessary. It was not enough. Therefore, for example, when an inorganic material is laminated on a film made of polyimide as described in Patent Document 3 under a relatively high temperature condition of 350 ° C. or higher, a layer made of an inorganic material It was not always possible to sufficiently suppress the occurrence of cracks in a part of the film or the occurrence of fine peeling between the layer made of an inorganic material due to the stress generated in the film. From this point of view, particularly when a final product is manufactured using a film made of polyimide, it is necessary to expose to a high temperature (for example, a layer made of an inorganic material needs to be laminated at a high temperature). In some cases, from the viewpoint of improving the yield of the final product, the appearance of a polyimide film capable of suppressing an increase in the linear expansion coefficient at a higher level at a high temperature (for example, a temperature of 350 ° C. or higher) is desired. ing.

  This invention is made | formed in view of the subject which the said prior art has, and is providing the polyimide film which is excellent in light transmittance and heat resistance, and has a sufficiently low linear expansion coefficient in high temperature, and its manufacturing method. Furthermore, it aims at providing the flexible wiring board, the board | substrate for transparent electrodes, the board | substrate for liquid crystal aligning film lamination | stacking, the board | substrate for organic EL displays, and the board | substrate for organic EL lighting which consist of the polyimide film.

  As a result of intensive studies to achieve the above object, the inventors of the present invention contain at least one of repeating units represented by the following general formulas (1) and (2), and the general formula (1) ) And (2), the total amount of repeating units is 90 mol% or more with respect to all repeating units, the linear expansion coefficient at 350 ° C. is 10 ppm / ° C. or less, and the rate of temperature rise in a nitrogen atmosphere For example, an inorganic material is laminated with a film made of polyimide having an average linear expansion coefficient of 15 ppm / ° C. or less obtained by measuring a change in length in a temperature range of 50 ° C. to 400 ° C. at 5 ° C./min. Therefore, it has been found that even when it is necessary to heat at a high temperature (for example, a temperature of 350 ° C. or higher), expansion due to heat can be sufficiently suppressed.

  As described above, the present inventors have conducted extensive research to achieve the above object, and as a result, the film made of the polyimide (polyimide film) is excellent in light transmittance and heat resistance, and also has a linear expansion coefficient at a high temperature. Was found that a sufficiently low polyimide film was obtained, and the present invention was completed.

  The polyimide film of the present invention has the following general formulas (1) and (2):

[In the formulas (1) and (2), R ¹ , R ² and R ³ each independently represent one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluorine atom. , R ⁴ represents an aryl group having 6 to 40 carbon atoms, and n represents an integer of 0 to 12. ]
Containing at least one of the repeating units represented by:
The total amount of the repeating units represented by the general formulas (1) and (2) is 90 mol% or more based on all repeating units,
The linear expansion coefficient at 350 ° C. is 10 ppm / ° C. or less, and
The average linear expansion coefficient determined by measuring the change in length in the temperature range of 50 ° C. to 400 ° C. under a temperature increase rate of 5 ° C./min under a nitrogen atmosphere is 15 ppm / ° C. or less.
It is a film made of polyimide.

  In the polyimide film of the present invention, the polyimide preferably has a linear expansion coefficient at 350 ° C. of 1 to 10 ppm / ° C. (more preferably 5 to 10 ppm / ° C.).

In the polyimide film of the present invention, the general formula (1) and (2) in ^{R 4} is represented by the following general formula (3) to (6):

[In the formula (5), R ⁵ represents one selected from the group consisting of a hydrogen atom, a fluorine atom, a methyl group, an ethyl group and a trifluoromethyl group, and in the formula (6), Q is a formula: _{-O -, - S -, -} CO -, - CONH -, - C 6 H 4 -, - COO -, - SO 2 -, - C (CF 3) 2 -, - C (CH 3) 2 -, _{-CH 2 -, - O-C} 6 H 4 -C (CH 3) 2 -C 6 H 4 -O -, - O-C 6 H 4 -SO 2 -C 6 H 4 -O -, - C ( _{CH 3) 2 -C 6 H 4} -C (CH 3) 2 -, - from _{O-C 6 H 4 -C 6} H 4 -O- and _{-O-C 6} group represented by H 4 -O- 1 type selected from the group consisting of ]
It is preferable that it is 1 type in group represented by these.

  Moreover, the manufacturing method of the polyimide film of this invention is the following general formula (7):

Wherein ^{(7), R 1, R} 2, R 3 are each independently a hydrogen atom, represents one selected from the group consisting of alkyl groups and fluorine atom having 1 to 10 carbon atoms, ^{R 4} is An aryl group having 6 to 40 carbon atoms is shown, and n is an integer of 0 to 12. ]
An alicyclic tetracarboxylic dianhydride (A) represented by the following general formula (8):

Wherein ^{(8), R 1, R} 2, R 3, n are as defined ^{R 1, R 2, R 3} , n in the general formula (7). ]
At least one of the alicyclic tetracarboxylic dianhydrides (B) represented by the formula (1) and the total amount of the alicyclic tetracarboxylic dianhydrides (A) and (B) is 90 mol. % Alicyclic tetracarboxylic dianhydride monomer,
The following general formula (9):

[In the formula (9), R ⁴ represents an aryl group having 6 to 40 carbon atoms. ]
The following general formulas (10) and (11) obtained by reacting with an aromatic diamine represented by:

In formula (10) and ^{(11), R 1, R} 2, R 3, n has the same meaning as ^{R 1, R 2, R 3} , n in the general formula (7), ^{R 4} is the general the same meaning as ^{R 4} in the formula (9). ]
Using a polyamic acid solution containing at least one type of repeating unit represented by formula (10) and a polyamic acid containing a polyamic acid having a total amount of repeating units represented by the general formulas (10) and (11) of 90 mol% or more, General formula (1) and (2):

[In the formulas (1) and (2), R ¹ , R ² and R ³ each independently represent one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluorine atom. , R ⁴ represents an aryl group having 6 to 40 carbon atoms, and n represents an integer of 0 to 12. ]
Polyimide containing at least one of the repeating units represented by the formula (1) and the total amount of the repeating units represented by the general formulas (1) and (2) being 90 mol% or more based on all repeating units. Obtaining a first film comprising:
The first film is stretched in an inert gas atmosphere at an atmospheric temperature of 370 to 450 ° C. so that the stretching ratio is 1.0001 to 1.050, thereby forming a second film. And obtaining a polyimide film,
It is the method characterized by including.

  In the method for producing a polyimide film of the present invention, when the first film is stretched, the stretch ratio is 1.0005 (more preferably 1.0010) to 1.030 times. It is preferable to stretch.

  Furthermore, in the method for producing a polyimide film of the present invention, the polyimide film has a linear expansion coefficient of 350 ° C. of 10 ppm / ° C. or less and a temperature of 5 ° C./min in a nitrogen atmosphere at 50 ° C./min. It is preferable that it consists of a polyimide whose average linear expansion coefficient calculated | required by measuring the change of length in a temperature range (degreeC-400 degreeC) is 15 ppm / degrees C or less.

  The flexible wiring substrate of the present invention, the substrate for transparent electrodes of the present invention, the substrate for laminating a liquid crystal alignment film of the present invention, the substrate for organic EL display of the present invention, and the substrate for organic EL lighting of the present invention It is characterized by comprising the polyimide film of the invention. Further, the transparent electrode substrate of the present invention is used for laminating any one of the transparent electrodes of the display device and the solar cell (transparent electrode substrate for display device and transparent electrode substrate for solar cell). Or any one of them) is preferred. Examples of such a display device include an organic electroluminescence display (organic EL display), a liquid crystal display device, and electronic paper. Moreover, the substrate for organic EL displays of the present invention is a substrate for laminating transparent electrodes used for organic EL displays, a barrier substrate used for organic EL displays, a thin film transistor substrate, a sealing layer substrate, a negative electrode substrate, an organic semiconductor substrate, a positive electrode. Examples thereof include those used as substrates, DC drive circuit substrates, hard coat substrates, front film substrates, and back film substrates.

  The reason why the polyimide film of the present invention has a sufficiently low linear expansion coefficient at a high temperature is not necessarily clear, but the reason will be briefly described in comparison with the prior art. That is, a conventional polyimide film (polyimide film as described in Patent Document 3) containing 90 mol% or more of the repeating units represented by the general formulas (1) and (2) is usually the main polymer. It is inferred that the chain has a so-called planar zigzag structure and a higher order structure is formed (planar zigzag structure obtained by molecular orbital calculation is shown in FIG. 1 and FIG. 2. This was carried out using MOPAC software equipped on Chem Bio3D Ultra10 using a FUJITSU FMV-B8200 personal computer.) And when it has such a higher order structure, the polyimide is oriented in the plane, the film in-plane direction (XY direction: the direction perpendicular to the film is the Z direction, and one direction perpendicular to the Z direction is the X direction. And the linear expansion coefficient in the case where the direction perpendicular to the Z direction and the X direction is the Y direction).

  However, even in the film made of polyimide described in Patent Document 3 containing the repeating units represented by the general formulas (1) and (2), the linear expansion coefficient at a high temperature (for example, a temperature of 350 ° C. or more). It was not always sufficient in terms of the suppression of the increase. Therefore, as a result of intensive studies to achieve the above object, the present inventors can suppress an increase in the linear expansion coefficient at a high temperature (for example, a temperature of 350 ° C. or higher) at a higher level. A film made of such a polyimide formed a first film made of polyimide containing a repeating unit represented by the general formulas (1) and (2) (film-like product: a precursor of the polyimide film of the present invention). Thereafter, the first film is stretched in an inert gas atmosphere at an atmospheric temperature of 370 to 450 ° C. so that the stretch ratio is 1.0001 to 1.050, and the second film (polyimide film) It has been found that it can be suitably produced by the method of forming a).

  Surprisingly, according to such a method, the linear expansion coefficient at 350 ° C. is 10 ppm / ° C. or less, and a temperature of 50 ° C. to 400 ° C. under a temperature increase rate of 5 ° C./min in a nitrogen atmosphere. The average linear expansion coefficient (hereinafter, simply referred to as “average linear expansion coefficient in the temperature range of 50 ° C. to 400 ° C.”) determined by measuring the change in length in the range is 15 ppm / ° C. or lower. In addition, a polyimide film (second film) having a sufficiently low linear expansion coefficient at a high temperature can be suitably produced. The reason why the polyimide film, which is the second film obtained after such stretching, can suppress an increase in the linear expansion coefficient at a high temperature (preferably a temperature of 350 ° C. or higher) is not necessarily clear. However, the present inventors infer that the stretching causes the structure to be more regularly oriented and the linear expansion coefficient in the stretching direction of the film to be lower at a higher level. In general, the alicyclic polyimide is considered to cause problems such as cracks in the film when it is simply stretched due to the rigid structure derived from the cyclic structure. In the above temperature atmosphere, by stretching while controlling the stretching ratio to be 1.0001 to 1.050, it becomes possible to stretch without causing coloring or cracks, and such It has been found that the stretching can sufficiently suppress an increase in the linear expansion coefficient at a high temperature. Thus, the polyimide film has a linear expansion coefficient of 350 ° C. or less of 10 ppm / ° C. or less because the higher order structure composed of a planar zigzag structure becomes a highly oriented planar zigzag structure by means of stretching or the like. And a high temperature such that the average linear expansion coefficient obtained by measuring a change in length in a temperature range of 50 ° C. to 400 ° C. under a temperature increase rate of 5 ° C./min in a nitrogen atmosphere is 15 ppm / ° C. or less. The present inventors infer that the film will be a film made of polyimide having a sufficiently low linear expansion coefficient.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the polyimide film which is excellent in light transmittance and heat resistance, and has a sufficiently low linear expansion coefficient in high temperature, and its manufacturing method. Furthermore, according to this invention, it becomes possible to provide the flexible wiring board which consists of the said polyimide film, the board | substrate for transparent electrodes, the board | substrate for liquid crystal aligning film lamination | stacking, the board | substrate for organic EL displays, and the board | substrate for organic EL lighting.

It is the schematic diagram obtained by calculating theoretically the principal chain structure of the polyimide when the conventional polyimide film of patent document 3 is seen from a direction perpendicular | vertical with respect to a film. It is the schematic diagram obtained by calculating theoretically the principal chain structure of the polyimide in the case of seeing the conventional polyimide film of patent document 3 from the horizontal direction. 2 is a graph of IR spectrum of a compound constituting the polyimide film obtained in Example 1. FIG. It is a graph which shows the relationship between the change of the length of the film calculated | required at the time of the measurement of the linear expansion coefficient of the polyimide which comprises the polyimide film obtained in Example 1, and temperature. It is a graph which shows the relationship between the change of the length of the film calculated | required at the time of the measurement of the linear expansion coefficient of the polyimide which comprises the polyimide film obtained by the comparative example 1, and temperature.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

  First, the polyimide of the present invention will be described. The polyimide film of the present invention has the following general formulas (1) and (2):

[In the formulas (1) and (2), R ¹ , R ² and R ³ each independently represent one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluorine atom. , R ⁴ represents an aryl group having 6 to 40 carbon atoms, and n represents an integer of 0 to 12. ]
Containing at least one of the repeating units represented by:
The total amount of the repeating units represented by the general formulas (1) and (2) is 90 mol% or more based on all repeating units,
The linear expansion coefficient at 350 ° C. is 10 ppm / ° C. or less, and
The average linear expansion coefficient determined by measuring the change in length in the temperature range of 50 ° C. to 400 ° C. under a temperature increase rate of 5 ° C./min under a nitrogen atmosphere is 15 ppm / ° C. or less.
It is a film made of polyimide.

The alkyl group that can be selected as R ¹ , R ² , or R ^{3 in the} general formulas (1) and (2) is an alkyl group having 1 to 10 carbon atoms. When such carbon number exceeds 10, a glass transition temperature will fall and the heat resistance of the film which consists of polyimides obtained will become inadequate. Moreover, as carbon number of the alkyl group which can be selected as such R < ¹ >, R < ² >, R < ³ >, it is preferable that it is 1-6 from a viewpoint that refinement | purification becomes easier, and it is 1-5. Is more preferable, it is still more preferable that it is 1-4, and it is especially preferable that it is 1-3. Further, such an alkyl group that can be selected as R ¹ , R ² , or R ³ may be linear or branched. Further, such an alkyl group is more preferably a methyl group or an ethyl group from the viewpoint of ease of purification.

R ¹ , R ² and R ^{3 in the} general formulas (1) and (2) are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms from the viewpoint of obtaining higher heat resistance. In particular, from the viewpoint of easy availability of raw materials and easier purification, each independently represents a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. It is more preferable that it is a hydrogen atom or a methyl group. Moreover, it is especially preferable that several R < ¹ >, R < ² >, R < ³ > in such a formula is the same from viewpoints, such as the ease of refinement | purification.

The aryl group that can be selected as R ⁴ in the general formulas (1) and (2) is an aryl group having 6 to 40 carbon atoms. Moreover, as such carbon number, it is preferable that it is 6-30, and it is more preferable that it is 12-20. If the number of carbons exceeds the upper limit, the glass transition temperature tends to decrease and sufficient heat resistance tends not to be obtained. On the other hand, if the carbon number is lower than the lower limit, the solubility of the obtained polyimide in the solvent decreases. Therefore, the moldability to a film or the like tends to be reduced.

Further, R ⁴ in the general formulas (1) and (2) has a sufficiently high glass transition temperature and a sufficiently low linear expansion coefficient at a high temperature, and exhibits these characteristics in a more balanced manner. From the viewpoint that it becomes possible, the following general formulas (3) to (6):

[In the formula (5), R ⁵ represents one selected from the group consisting of a hydrogen atom, a fluorine atom, a methyl group, an ethyl group and a trifluoromethyl group, and in the formula (6), Q is a formula: _{-O -, - S -, -} CO -, - CONH -, - C 6 H 4 -, - COO -, - SO 2 -, - C (CF 3) 2 -, - C (CH 3) 2 -, —CH ₂ —, —O—C ₆ H ₄ —C (CH ₃ ) ₂ —C ₆ H ₄ —O—, —O—C ₆ H ₄ —SO ₂ —C ₆ H ₄ —O—, —C ( _{CH 3) 2 -C 6 H 4} -C (CH 3) 2 -, - from _{O-C 6 H 4 -C 6} H 4 -O- and _{-O-C 6} group represented by H 4 -O- 1 type selected from the group consisting of ]
It is preferable that it is 1 type in group represented by these.

R ⁵ in the general formula (5) is a hydrogen atom, a fluorine atom, from the viewpoint that the glass transition temperature and the linear expansion coefficient can be balanced and at a higher level. , A methyl group or an ethyl group is more preferable, and a hydrogen atom is particularly preferable.

Moreover, as Q in the said General formula (6), it is a formula: -O-, -S-, -CONH- from a viewpoint of making a glass transition temperature and a linear expansion coefficient into a high level with a good balance. , —COO—, —CO—, —C ₆ H ₄ —, —CH ₂ —, —O—C ₆ H ₄ —O—, —O—C ₆ H ₄ —C ₆ H ₄ —O—. A group represented by the formula: —O—, —CONH—, —COO—, —CH ₂ —, and more preferably a group represented by the formula: —O— or —CONH—. Particularly preferred is a group.

Moreover, as group represented by General formula (3)-(6) which can be selected as such R < ⁴ >, while being able to make glass transition temperature sufficiently high temperature, a linear expansion coefficient more fully The value can be lowered, the balance of these characteristics is improved, and higher thermal shock resistance (resistance to sufficiently maintain the quality against the temperature change of the surrounding high temperature, for example, 350 ° C. or more From the viewpoint of obtaining resistance to sufficiently prevent peeling and cracking even under such temperature conditions when it is necessary to employ a process of laminating an inorganic layer under such high temperature conditions. Is more preferably a group represented by the general formula (5) or (6). Among these, from the viewpoint that the linear expansion coefficient at a high temperature can be made sufficiently lower, R ⁴ is represented by the group represented by the general formula (5) or the general formula (6) and A group represented by Q represented by —CONH—, —COO—, —CO—, —C ₆ H ₄ — (more preferably a group represented by —CONH— or —COO—, particularly preferably —CONH—; It is preferable that it is a group which is at least one of the represented groups. Furthermore, R ⁴ is represented by the general formula (3) from the viewpoint that when a film is formed using the obtained polyimide, a high degree of flexibility (flexibility) can be imparted to the film. Or Q is —O—, —S—, —CH ₂ —, —O—C ₆ H ₄ —O— or —O—C ₆ H ₄ —C. _At least one of groups represented by ₆ H ₄ —O— (more preferably one of groups represented by —O— and —CH ₂ —, more preferably —O—. Group) is preferable.

  Moreover, n in the said General formula (1) and (2) shows the integer of 0-12. When such a value of n exceeds the upper limit, purification becomes difficult. In addition, the upper limit of the numerical value range of n in the general formulas (1) and (2) is more preferably 5 and particularly preferably 3 from the viewpoint of easier purification. . Moreover, the lower limit of the numerical value range of n in such general formula (1) and (2) is the monomer (For example, the below-mentioned alicyclic tetracarboxylic dianhydride (A) and ( From the viewpoint of the stability of the raw material of the alicyclic tetracarboxylic dianhydride monomer containing B), 1 is more preferable, and 2 is particularly preferable. Thus, as n in general formula (1) and (2), it is especially preferable that it is an integer of 2-3.

Furthermore, as such a polyimide, a sufficiently high glass transition temperature, a sufficiently low linear expansion coefficient at a high temperature (preferably 350 ° C.), and a sufficient flexibility (flexibility) of the film when a film is formed. From the viewpoint of exhibiting the above in a more balanced manner at a high level, in the polyimide, at least two types of repeating units represented by the general formulas (1) and (2) having different types of R ⁴ are used. It is preferable to contain a unit. In this case, for example, examples of the polyimide containing different repeating units of ^{R 4, R 4} is a group represented by the general formula (5); and wherein Q is -CONH -, - COO -, - CO—, a group represented by —C ₆ H ₄ — (more preferably a group represented by —CONH—, —COO—, particularly preferably a group represented by —CONH—). A repeating unit comprising at least one of the repeating units represented by the general formulas (1) and (2), which is one group selected from the group consisting of the group represented by the general formula (6). (A) and R ⁴ are groups represented by the general formula (3); and Q is —O—, —S—, —CH ₂ —, —O—C ₆ H ₄ —O—, — One of the groups represented by O—C ₆ H ₄ —C ₆ H ₄ —O— (more preferably —O—, —CH _A group selected from the group consisting of: a group represented by the above general formula (6), which is a group represented by 2-O, more preferably a group represented by -O-. It is good also as what contains the repeating unit (B) which consists of at least 1 sort (s) among the repeating units represented by General formula (1) and (2) which is. In addition, as such a repeating unit (B), from the viewpoint of easy availability of the monomer during production, R ⁴ is a group represented by the general formula (6) and the formula (6). One of the groups in which Q is represented by —O—, —CH ₂ —, —O—C ₆ H ₄ —O—, —O—C ₆ H ₄ —C ₆ H ₄ —O— ( More preferably, one of groups represented by —O—, —CH ₂ —, —O—C ₆ H ₄ —C ₆ H ₄ —O—, still more preferably —O—, —O—C _6. those wherein H ₄ -C ₆ H ₄ -O- group represented by) is more preferable.

  In the polyimide according to the present invention, the total amount of the repeating units represented by the general formulas (1) and (2) is 90 mol% or more based on all repeating units. When such a content ratio is less than the lower limit, a sufficiently high linear expansion coefficient at a high temperature (lower linear expansion coefficient at a high temperature) cannot be achieved. The content ratio (total amount) of the repeating units represented by the general formulas (1) and (2) is more preferably 95 to 100 mol% with respect to all repeating units, and 98 to 100 mol. % Is more preferable, and 100 mol% is particularly preferable. In addition, it does not restrict | limit especially as repeating units other than the repeating unit represented by the said General formula (1) and (2), According to a use etc., the other repeating unit derived from a well-known monomer is selected suitably. Can be used.

  Further, in the polyimide according to the present invention, it is sufficient if it contains at least one of the repeating units represented by the general formulas (1) and (2). The ratio of the repeating unit represented by the general formula (1) to the repeating unit represented by the general formula (2) is 1: 2 in molar ratio ([formula (1)]: [formula (2)]). Is preferably ˜2: 1, more preferably 1: 1.85 to 1.85: 1, and even more preferably 1: 1.7-1 to 1.7: 1. When the content ratio of the repeating unit represented by the general formula (1) is less than the lower limit, the film tends to be brittle. On the other hand, when the content exceeds the upper limit, the film tends to become brittle.

Further, in the polyimide according to the present invention, when the repeating units (A) and (B) are contained as the repeating units represented by the general formulas (1) and (2), these repeating units are combined. From the viewpoint of obtaining the effect achieved by the above, the total amount of the repeating units (A) and (B) is preferably 90 mol% or more with respect to all the repeating units, and is 95 to 100 mol%. More preferably, it is 98 to 100 mol%, further preferably 100 mol%. When such repeating units (A) and (B) are contained, the content ratio of the repeating unit (A) to the repeating unit (B) is 9 in molar ratio ((A) :( B)). : 1 to 6: 4 (more preferably 8: 2 to 7: 3). In the case of containing the repeating unit (A) and (B), more from the viewpoint of efficiently polyimide can be prepared by the general formula (1) and (2) configuration of substituents other than R ⁴ in the Preferably they are the same.

  The polyimide according to the present invention has a linear expansion coefficient at 350 ° C. of 10 ppm / ° C. or less. When such a linear expansion coefficient exceeds the upper limit, the film is cracked at a high temperature, and it tends to be difficult to sufficiently suppress deterioration in quality. For example, in a film made of polyimide having a linear expansion coefficient exceeding the upper limit, when the film is used for manufacturing a solar cell or a liquid crystal display device, it is exposed to a high temperature (for example, a high temperature of 350 ° C. or higher) in the manufacturing process. In some cases, the film may be cracked and the like, which is not necessarily sufficient in terms of suppressing a decrease in product yield. On the other hand, as described in the present invention, when the linear expansion coefficient at 350 ° C. is 10 ppm / ° C. or less, in the manufacturing process of the solar cell or the liquid crystal display device, the cracking of the film, etc. at a higher level. This can also improve the final product yield.

  Moreover, as such a linear expansion coefficient of 350 degreeC, although it changes according to a use, it is preferable that it is 1-10 ppm / degreeC, It is more preferable that it is 5-10 ppm / degreeC, 4-8 ppm More preferably, the temperature is / ° C. When such a linear expansion coefficient of 350 ° C. is within the above-mentioned preferable numerical range, a higher effect tends to be obtained in terms of suppressing deterioration of film quality at high temperatures. Further, when such a linear expansion coefficient is less than the lower limit, the product tends to be cracked, curled, distorted, peeled, peeled, or distorted. In addition, "350 degreeC linear expansion coefficient" here means the average value of the linear expansion coefficient of a polyimide in the temperature range of 349 degreeC-351 degreeC.

  The polyimide according to the present invention has an average linear expansion coefficient of 15 ppm / ° C. or less in a temperature range of 50 ° C. to 400 ° C. When the average linear expansion coefficient in such a temperature range of 50 ° C. to 400 ° C. exceeds the upper limit, the film is cracked at a high temperature, and it is difficult to sufficiently suppress deterioration in quality. As an average linear expansion coefficient in such a temperature range of 50 ° C. to 400 ° C., although it varies depending on the application, it is preferably 1 to 13 ppm / ° C., more preferably 4 to 10 ppm / ° C. preferable. When such an average linear expansion coefficient is in the above-mentioned preferable numerical range, a higher effect tends to be obtained in terms of suppressing deterioration of film quality at high temperatures. Further, when such an average linear expansion coefficient is less than the lower limit, the product tends to be cracked, curled, distorted, peeled, peeled off, or distorted.

  Moreover, in the polyimide concerning this invention, it is preferable that the average linear expansion coefficient in a temperature range of 50 degreeC-200 degreeC is 15 ppm / degrees C or less, It is preferable that it is 1-12 ppm / degreeC, It is 4-10 ppm. / ° C is more preferable. When the average linear expansion coefficient in such a temperature range of 50 ° C. to 200 ° C. exceeds the upper limit, the product tends to crack, curl, strain, peel, peel, or distort, and on the other hand, if it is less than the lower limit, the product cracks. , Curl, distortion, peeling, peeling and distortion tend to occur.

  In the present invention, the linear expansion coefficient of the polyimide (including a linear expansion coefficient of 350 ° C., an average linear expansion coefficient in a temperature range of 50 ° C. to 400 ° C., an average linear expansion coefficient in a temperature range of 50 ° C. to 200 ° C., etc. The method as described below is adopted as the measuring method.

  That is, first, after forming a film (sample precursor) made of polyimide having a length of 20 mm, a width of 5 mm, and a thickness of 0.013 mm (13 μm), the film was vacuum-dried (at 120 ° C. for 1 hour), A sample for measurement is formed by heat treatment at 200 ° C. for 1 hour in an atmosphere. Next, using such a sample for measurement and using a thermomechanical analyzer (trade name “TMA8310” manufactured by Rigaku) as a measuring device, in a nitrogen atmosphere, in a tensile mode (49 mN), a rate of temperature increase The change in the length of the sample in the longitudinal direction is continuously measured in the temperature range of 50 ° C. to 400 ° C. under the condition of 5 ° C./min (the length of the sample in the longitudinal direction at 50 ° C. to 400 ° C. Measurement of change data). When the sample precursor is formed by employing a stretching process (uniaxial stretching process), the stretching direction is the longitudinal direction of the film (the sample precursor).

  After determining the average linear expansion coefficient in the temperature range of 50 ° C. to 400 ° C. after such measurement, based on the data on the change in the longitudinal length of the sample at 50 ° C. to 400 ° C. A method for obtaining an average value of changes in length per 1 ° C in a temperature range of ˜400 ° C. is adopted, and an average value obtained by such a method is adopted as an average linear expansion coefficient in a temperature range of 50 ° C. to 400 ° C. (Measurement method of average linear expansion coefficient in a temperature range of 50 ° C. to 400 ° C.).

  Moreover, when calculating | requiring the average linear expansion coefficient in the temperature range of 50 degreeC-200 degreeC after the above measurements, the longitudinal direction of the said sample in the temperature range of 50 degreeC-400 degreeC obtained as mentioned above The change in length per 1 ° C. in the temperature range of 50 ° C. to 200 ° C. is obtained using the data of the change in the longitudinal length of the sample at 50 ° C. to 200 ° C. A method for obtaining an average value is adopted, and an average value obtained by such a method is adopted as an average linear expansion coefficient in a temperature range of 50 ° C. to 200 ° C. (Measurement of average linear expansion coefficient in a temperature range of 50 ° C. to 200 ° C. Method).

  Furthermore, after obtaining the above-mentioned measurement, when obtaining the above-mentioned linear expansion coefficient number of 350 ° C., the length of the sample in the longitudinal direction in the temperature range of 50 ° C. to 400 ° C. obtained as described above. From the change data, using the change data of the longitudinal length of the sample in the temperature range of 349 ° C. to 351 ° C., the longitudinal direction of the sample per 1 ° C. in the temperature range of 349 ° C. to 351 ° C. A method of obtaining an average value of changes in length is adopted, and the average value obtained by such a method is adopted as the number of linear expansion coefficients at 350 ° C. (measurement method of the number of linear expansion coefficients at 350 ° C.).

  In the polyimide according to the present invention, the glass transition temperature is preferably 350 ° C. or higher (more preferably 350 ° C. to 500 ° C.), more preferably 360 ° C. to 500 ° C., and more preferably 370 to 450 ° C. It is particularly preferable to do this. When such a glass transition temperature is less than the lower limit, the heat resistance is lowered. For example, when a polyimide film is used as a substrate for a transparent electrode of a solar cell or a liquid crystal display device, Therefore, it tends to be difficult to sufficiently suppress the deterioration of quality (such as generation of cracks) of the film (substrate).

  The glass transition temperature is preferably higher from the viewpoint of heat resistance. Moreover, 500 degreeC which is the upper limit of the said glass transition temperature is temperature near the measurement upper limit of the glass transition temperature at the time of employ | adopting the below-mentioned measuring method. Thus, since the measurement upper limit of the glass transition temperature when the measurement method described later is adopted is about 500 ° C., for a polyimide whose glass transition temperature is not measured up to 500 ° C., for example, the softening temperature A suitable value may be determined using the upper limit value as an index. That is, as the polyimide according to the present invention, those having a softening temperature in the temperature range described later can be suitably used regardless of the glass transition temperature. For example, the glass transition temperature is measured at a temperature exceeding 500 ° C. If not, the upper limit value of the softening temperature may be used as an index of a suitable polyimide to evaluate the characteristics. In this case, the softening temperature does not exceed the upper limit of the numerical range described later. It is preferable. In addition, a polyimide whose glass transition temperature is not measured up to 500 ° C. and whose softening temperature exceeds the upper limit of the softening temperature described below is sufficient to produce a solid phase sufficient simultaneously with the thermal ring closure condensation reaction of polyamic acid. When the polymerization reaction does not proceed and a film is formed, the film tends to be brittle.

  The glass transition temperature of such a polyimide is measured by using a differential scanning calorimeter (for example, trade name “DSC7020” manufactured by SII Nano Technology Co., Ltd.) as a measuring device. : A value obtained by scanning between 30 ° C. and 450 ° C. in a nitrogen atmosphere under a condition of 30 ° C./min can be employed. In addition, about the polyimide which does not have glass transition temperature between scanning temperature 30 degreeC to 450 degreeC, the above-mentioned scanning temperature is changed from 30 degreeC to 500 degreeC, and glass transition temperature is measured.

  Moreover, as such a polyimide, that whose 5% weight reduction temperature is 450 degreeC or more is preferable, and the thing of 460-550 degreeC is more preferable. If such a 5% weight loss temperature is less than the lower limit, sufficient heat resistance (including thermal shock resistance) tends to be not obtained when a film is formed. It tends to be difficult to produce polyimide having characteristics. Such 5% weight reduction temperature is obtained by gradually heating from room temperature (25 ° C.) while flowing nitrogen gas in a nitrogen gas atmosphere and measuring the temperature at which the weight of the used sample is reduced by 5%. Can be sought.

  Moreover, as such a polyimide, that whose softening temperature is 350-550 degreeC is preferable, and the thing of 360-500 degreeC is more preferable. When the softening temperature is lower than the lower limit, the heat resistance is lowered. For example, in the case where a polyimide film is used as a substrate for a transparent electrode of a solar cell or a liquid crystal display device, it takes a heating step in the manufacturing process of the product. On the other hand, it tends to be difficult to sufficiently suppress deterioration of film (substrate) quality (such as occurrence of cracks). On the other hand, when the above upper limit is exceeded, simultaneously with the thermal ring closure condensation reaction of polyamic acid, Sufficient solid phase polymerization reaction does not proceed, and when a film is formed, it tends to be a brittle film. In addition, the softening temperature of such a polyimide can be measured as follows. That is, a film made of polyimide having a size of 5 mm in length, 5 mm in width and 0.013 mm (13 μm) in thickness was prepared as a measurement sample, and a thermomechanical analyzer (trade name “TMA8311” manufactured by Rigaku) was used as a measurement device. Adopting a transparent quartz pin (tip diameter: 0.5 mm) into the film under a temperature range of 30 ° C. to 550 ° C. under a nitrogen atmosphere, using a temperature rising rate of 5 ° C./min. (It can be measured by a so-called penetration method.) In such a measurement, softening is performed based on measurement data in accordance with the method described in JIS K 7196 (1991). Calculate the temperature.

  Furthermore, regarding the molecular weight of such a polyimide, the film after thermal imidization may be difficult to dissolve in a general-purpose organic solvent, so the molecular weight is evaluated using the intrinsic viscosity [η] of the polyamic acid that is the precursor. Can be measured. The intrinsic viscosity [η] of the polyamic acid which is such a precursor is preferably 0.1 to 8.0 dL / g, more preferably 0.1 to 6.0 dL / g, More preferably, it is 0.1-3.0 dL / g, and it is especially preferable that it is 0.4-2.0 dL / g. If the intrinsic viscosity is less than the lower limit, it becomes difficult to obtain sufficient heat resistance, and the linear expansion coefficient at a high temperature tends to increase. (Cast film formation) tends to be difficult. Such intrinsic viscosity [η] can be measured as follows. That is, first, a measurement sample (solution) in which N, N-dimethylacetamide is used as a solvent and the polyamic acid is dissolved in the N, N-dimethylacetamide so as to have a concentration of 0.5 g / dL. obtain. Next, using the measurement sample, the viscosity of the measurement sample is measured using a kinematic viscometer under a temperature condition of 30 ° C., and the obtained value is adopted as the intrinsic viscosity [η]. In addition, as such a kinematic viscometer, an automatic viscosity measuring apparatus (trade name “VMC-252”) manufactured by Koiso Co., Ltd. is used.

  In addition, in such a polyimide, it is desirable that acid dianhydrides and diamines as structural units have a rigid and symmetric structure and have a polar group capable of interacting between molecules. For example, it is preferable to form a structure having a skeleton such as a cyclic structure, a polycyclic structure, a spiro structure, a bridged cyclic structure, and a heterocyclic structure, and further having a polar group such as a ketone, sulfone, amide, and imide. Moreover, it is preferable that such a polyimide has a structure in which orientation is sufficiently formed. By having these structures, it becomes possible to make polyimide have a sufficiently low linear expansion coefficient. The structure of the polymer chain of such a polyimide can be determined by calculating the molecular orbital of the polyimide based on the type of monomer used (for example, equipped with Chem Bio3D Ultra 10 using a FUJITSU FMV-B8200 personal computer). The formed polyimide is drawn on Chem Bio3D Ultra10 using the MOPAC software, and the stable structure of the resulting polymer can be determined by simulating the stable structure of the resulting polymer by calculating MM2. Such a polymer structure can also be obtained by measuring the linear expansion coefficient in the Z direction of the polyimide thin film using an optical interference method and clarifying the relationship between the linear expansion coefficient and the molecular structure.

  Furthermore, the specific shape (size and thickness) of the film made of such polyimide is not particularly limited, and can be appropriately designed according to the use of the film. Thus, the thickness of the film is not particularly limited, but is preferably 1 to 200 μm, more preferably 1 to 100 μm, further preferably 5 to 50 μm, and 10 to 20 μm. It is particularly preferred. If the thickness of such a film is less than the above lower limit, the mechanical strength tends to be reduced and weakened when used for various applications, and on the other hand, if it exceeds the upper limit, film forming tends to be difficult. .

  Further, such a film made of polyimide is preferably sufficiently high in transparency, and has a total light transmittance of 80% or more (more preferably 85% or more, particularly preferably 87% or more). Is more preferable. Such total light transmittance can be easily achieved by appropriately selecting the type of polyimide or the like. In addition, as such a total light transmittance, the value measured using the Nippon Denshoku Industries Co., Ltd. brand name "Hazemeter NDH-5000" as a measuring apparatus is employable.

  Furthermore, the film made of such a polyimide preferably has a refractive index of 1.50 to 1.70, and more preferably 1.55 to 1.65. When the refractive index is less than the lower limit, the difference in refractive index between polyimide and the conductive thin film becomes large when a laminate with the conductive thin film is formed and used for transparent applications, and the total light transmittance is On the other hand, when it exceeds the upper limit, the polyimide tends to be colored and the monomer synthesis itself tends to be difficult. As such a refractive index, a value measured under a temperature condition of 23 ° C. under a light source of 589 nm using a refractive index measuring device (trade name “NAR-1T SOLID” manufactured by Atago Co., Ltd.) is adopted. be able to.

  A film made of such a polyimide is colorless and transparent, yet has sufficient heat resistance, despite being a film made of an aliphatic polyimide obtained using an aliphatic tetracarboxylic dianhydride. The glass transition temperature (Tg) and softening temperature which are high and are sufficiently high compared with the polyimide made from a conventionally well-known aliphatic tetracarboxylic dianhydride can also be used. Moreover, the polyimide which forms such a film can also have a sufficiently high solubility in a solvent. Furthermore, such a film made of polyimide has a sufficiently low linear expansion coefficient.

  Such polyimide films (films made of polyimide) of the present invention are flexible wiring boards, polyimide films used for heat-resistant insulating tapes, substrates for liquid crystal alignment films (substrates for laminating liquid crystal alignment films), and substrates for printable electronics. Polyimide film, transparent electrode substrate (for example, ITO film substrate, solar cell transparent electrode substrate, organic EL element transparent electrode substrate, electronic paper substrate, etc.), polyimide for lithium ion battery Film (for example, film used for separator), touch panel substrate, organic EL display substrate, organic EL lighting substrate, water vapor barrier film substrate, air barrier film substrate, organic memory substrate, organic transistor substrate, organic semiconductor substrate, Useful for copier belts, etc.

  Next, the flexible wiring board of the present invention, the transparent electrode substrate of the present invention, the liquid crystal alignment film lamination substrate of the present invention, the organic EL display substrate of the present invention, and the organic EL lighting substrate of the present invention will be described. .

  The flexible wiring substrate of the present invention, the substrate for transparent electrodes of the present invention, the substrate for laminating a liquid crystal alignment film of the present invention, the substrate for organic EL display of the present invention, and the substrate for organic EL lighting of the present invention are each of the above-mentioned present invention. It consists of a polyimide film. As such a flexible wiring substrate, the polyimide film of the present invention may be used as a substrate, and other configurations are not particularly limited.

  Moreover, what is necessary is just to utilize the polyimide film of the said this invention as this board | substrate as this board | substrate for transparent electrodes, and another structure is not restrict | limited in particular. Such a transparent electrode substrate is used for laminating a transparent electrode of any one of a display device and a solar cell (a transparent electrode substrate for a display device and a transparent electrode for a solar cell). It is preferably any one of the substrates. Examples of such a display device include an organic electroluminescence display (organic EL display), a liquid crystal display device, and electronic paper. In the present invention, since the polyimide film of the present invention is used, the polyimide film (substrate) can be used even when a high temperature condition (for example, a temperature of 350 ° C. or higher) is adopted when laminating the transparent electrode. It is possible to sufficiently improve the yield of the final product without damage or the like.

  Further, the substrate for laminating liquid crystal alignment films is a substrate for laminating liquid crystal alignment films. In the present invention, as a substitute for a glass substrate or the like, the substrate made of the polyimide film of the present invention is used as a substrate for laminating a liquid crystal alignment film. An alignment layer stack can be manufactured. Moreover, as said liquid crystal aligning film lamination | stacking board | substrate, what is necessary is just to utilize the polyimide film of the said invention as this board | substrate, and another structure is not restrict | limited in particular.

  Furthermore, the organic EL display substrate (organic electroluminescence display substrate) of the present invention is not particularly limited as long as it is a substrate used for an organic EL display. For example, a substrate for laminating transparent electrodes or an organic EL display It may be used as a barrier substrate, a thin film transistor substrate, a sealing layer substrate, a negative electrode substrate, an organic semiconductor substrate, a positive electrode substrate, a DC drive circuit substrate, a hard coat substrate, a front film substrate, and a back film substrate. Moreover, what is necessary is just to utilize the said polyimide film of this invention as this board | substrate as said board | substrate for organic EL displays, and another structure is not restrict | limited in particular. By using a substrate made of the polyimide film of the present invention as such a substrate, a sufficiently flexible product can be manufactured as compared with a glass substrate or the like.

  The substrate for organic EL lighting of the present invention may be a substrate used for organic EL lighting (for example, an organic EL lighting panel). For example, a substrate for laminating transparent electrodes for organic EL lighting, an anode substrate, an organic positive electrode, and the like. It may be used as a hole transport layer substrate, an organic light emitting layer substrate, an organic electron transport layer substrate, a cathode substrate, an injection layer substrate, or a barrier layer substrate. In addition, as the organic EL lighting substrate, the polyimide film of the present invention may be used as such a substrate, and other configurations are not particularly limited. By using a substrate made of the polyimide film of the present invention as such a substrate, a sufficiently flexible product can be manufactured as compared with a glass substrate or the like.

  Next, the manufacturing method of the polyimide film of this invention is demonstrated. The production method of the polyimide film of the present invention is represented by the following general formula (7):

Wherein ^{(7), R 1, R} 2, R 3 are each independently a hydrogen atom, represents one selected from the group consisting of alkyl groups and fluorine atom having 1 to 10 carbon atoms, ^{R 4} is An aryl group having 6 to 40 carbon atoms is shown, and n is an integer of 0 to 12. ]
An alicyclic tetracarboxylic dianhydride (A) represented by the following general formula (8):

Wherein ^{(8), R 1, R} 2, R 3, n are as defined ^{R 1, R 2, R 3} , n in the general formula (7). ]
At least one of the alicyclic tetracarboxylic dianhydrides (B) represented by the formula (1) and the total amount of the alicyclic tetracarboxylic dianhydrides (A) and (B) is 90 mol. % Alicyclic tetracarboxylic dianhydride monomer,
The following general formula (9):

[In the formula (9), R ⁴ represents an aryl group having 6 to 40 carbon atoms. ]
The following general formulas (10) and (11) obtained by reacting with an aromatic diamine represented by:

In formula (10) and ^{(11), R 1, R} 2, R 3, n has the same meaning as ^{R 1, R 2, R 3} , n in the general formula (7), ^{R 4} is the general the same meaning as ^{R 4} in the formula (9). ]
A polyamic acid solution containing at least one repeating unit represented by the formula (10) and a polyamic acid containing a polyamic acid having a total amount of repeating units represented by the general formulas (10) and (11) of 90 mol% or more, It contains at least one of the repeating units represented by the general formulas (1) and (2), and the total amount of the repeating units represented by the general formulas (1) and (2) Step (I) for obtaining a first film made of polyimide that is 90 mol% or more,
The first film is stretched in an inert gas atmosphere at an atmospheric temperature of 370 to 450 ° C. so that the stretching ratio is 1.0001 to 1.050, thereby forming a second film. And obtaining a polyimide film (II),
It is the method characterized by including. Hereinafter, steps (I) to (II) will be described separately.

(Step (I): Step for obtaining the first film)
First, step (I) will be described. Step (I) contains at least one of the alicyclic tetracarboxylic dianhydride (A) and the alicyclic tetracarboxylic dianhydride (B), and the alicyclic tetra Reaction of an alicyclic tetracarboxylic dianhydride monomer having a total amount of carboxylic dianhydrides (A) and (B) of 90 mol% or more with an aromatic diamine represented by the general formula (9) The total amount of the repeating units represented by the general formulas (10) and (11) is 90 mol%. Using the polyamic acid solution containing the above polyamic acid, the polyamic acid solution contains at least one of the repeating units represented by the general formulas (1) and (2), and the general formulas (1) and ( 2) The total amount of the repeating unit represented by A step of obtaining a first film made of polyimide is 90 mol% or more repeating units.

  First, the polyamic acid solution used in such step (I) will be described. The polyamic acid contained in the polyamic acid solution used in the step (I) is composed of the alicyclic tetracarboxylic dianhydride (A) and the alicyclic tetracarboxylic dianhydride (B). An alicyclic tetracarboxylic dianhydride-based monomer containing at least one of them and having a total amount of the alicyclic tetracarboxylic dianhydrides (A) and (B) of 90 mol% or more, It is obtained by reacting the aromatic diamine represented by the general formula (9).

  Such an alicyclic tetracarboxylic dianhydride (A) is trans, endo, endo-norbornane-2-spiro-α-cycloalkanone-α'-spiro- represented by the above general formula (7). 2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic dianhydride. The alicyclic tetracarboxylic dianhydride (B) is a cis, endo, endo-norbornane-2-spiro-α-cycloalkanone-α′-spiro- represented by the general formula (8). 2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic dianhydride.

The alicyclic tetracarboxylic dianhydride (A) represented by the general formula (7) (trans, endo, endo-norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ′ '-Norbornane-5,5'',6,6''-tetracarboxylic dianhydride) is a compound that can be used as a material (monomer) for forming the polyimide according to the present invention. And a compound used to form a repeating unit represented by the general formula (1) (trans, end, end type repeating unit) in polyimide. ^{Therefore, R 1, R 2, R} 3, n in the alicyclic tetracarboxylic dianhydride represented by the general formula (7) (A) is, ^{R 1} in the general formula (1) , R ² , R ³ , and n (preferable ones are also the same). In addition, in the alicyclic tetracarboxylic dianhydride (A) represented by the general formula (7), two norbornane groups are arranged in trans, and a cycloalkanone is provided for each of the two norbornane groups. Norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid dianhydride in which the carbonyl group of the is in the endo configuration Is an isomer of the product.

In addition, the alicyclic tetracarboxylic dianhydride (B) represented by the general formula (8) (cis, endo, endo-norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ′ '-Norbornane-5,5'',6,6''-tetracarboxylic dianhydride) is a compound that can be used as a material (monomer) for forming the polyimide according to the present invention. And a compound used for forming a repeating unit (cis, end, end type repeating unit) represented by the general formula (2) in the polyimide. Therefore, in the alicyclic tetracarboxylic dianhydride represented by the general formula ^{(8) (B) R 1} , R 2, R 3, n is, ^{R 1} in the general formula (2) , R ² , R ³ , and n (preferable ones are also the same). ^{Incidentally, R 1, R 2, R} 3, n in the alicyclic tetracarboxylic dianhydride represented by the general formula (8) (B) is, ^{R 1} in the general formula (7) , R ² , R ³ and n have the same meaning (the preferred ones are also the same). In such an alicyclic tetracarboxylic dianhydride (B) represented by the general formula (8), two norbornane groups are placed in cis configuration, and each of the two norbornane groups is a carbonyl of cycloalkanone. Of norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic dianhydride in which the group is in the endo configuration Isomer.

  The alicyclic tetracarboxylic dianhydride monomer is a monomer composed of alicyclic tetracarboxylic dianhydride (note that other compounds other than the alicyclic tetracarboxylic dianhydride are substantially Are not included). In such an alicyclic tetracarboxylic dianhydride monomer, the total amount (content) of the alicyclic tetracarboxylic dianhydrides (A) and (B) is a total alicyclic tetracarboxylic dianhydride. It is 90 mol% or more based on the product (total monomers). As described above, the alicyclic tetracarboxylic dianhydride monomer is an alicyclic tetracarboxylic dianhydride represented by the general formulas (7) and (8) (the alicyclic tetracarboxylic dianhydride). It is a monomer composed of alicyclic tetracarboxylic dianhydride having a purity of anhydride (A) and (B)) of 90 mol% or more. Using an alicyclic tetracarboxylic dianhydride monomer in which the total amount (content ratio) of the alicyclic tetracarboxylic dianhydride represented by the general formulas (7) and (8) is less than the lower limit, When polyimide is produced, a sufficiently low linear expansion coefficient at a high temperature cannot be obtained. From the same viewpoint, the alicyclic tetracarboxylic dianhydrides represented by the general formulas (7) and (8) (the alicyclic tetracarboxylic dianhydrides (A) and (B)) The total amount (content ratio) is preferably 95 mol% or more, preferably 98 to 100 mol%, and 100 mol% with respect to the total alicyclic tetracarboxylic dianhydride. Particularly preferred.

  The alicyclic tetracarboxylic dianhydride monomer may be an alicyclic tetracarboxylic dianhydride represented by the general formulas (7) and (8) (the alicyclic tetracarboxylic dianhydride). It is sufficient that at least one of the products (A) and (B)) is contained. When both are contained, the alicyclic tetracarboxylic dianhydride (A) represented by the general formula (7) And the content ratio of the alicyclic tetracarboxylic dianhydride (B) represented by the general formula (8) is 1: 2 in terms of molar ratio ([formula (7)]: [formula (8)]). The ratio is preferably 2: 1, more preferably 1: 1.85 to 1.85: 1, and still more preferably 1: 1.7 to 1.7: 1. If such a molar ratio is less than the lower limit, the resulting polyimide film tends to be brittle, and on the other hand, even if the upper limit is exceeded, the resulting polyimide film tends to be brittle.

  In addition, the total amount (content) of the alicyclic tetracarboxylic dianhydride represented by the general formula (7) and the general formula (8) in the alicyclic tetracarboxylic dianhydride monomer. Alternatively, the molar ratio ([formula (7)]: [formula (8)]) is obtained by, for example, obtaining the peak area ratio based on each isomer based on the graph of the spectrum obtained by HPLC measurement, It can obtain | require by calculating using.

  In addition, such HPLC measurement uses a trade name “1200 Series” manufactured by Agilent Technologies, Inc. as a measuring device, and the column uses a trade name “Eclipse XDB-C18 (5 μm, diameter 4.6 mm, manufactured by Agilent Technologies, Inc.). 150 mm in length), a mixture of acetonitrile and distilled water (acetonitrile / distilled water = 70 ml / 30 ml) as a solvent, and a solvent flow rate of 1 ml / min. And setting the detection wavelength of the diode array detector (DAD) to 210 nm, setting the temperature to 35 ° C., and adding 1 mg of alicyclic tetracarboxylic dianhydride to 1.5 ml of the solvent. It can be carried out. The calibration curve can be obtained by obtaining an HPLC spectrum under the same measurement conditions using dicyclopentadiene or naphthalene as a standard sample. Moreover, in the graph of the HPLC spectrum, the peak area ratio based on each isomer can be directly determined by the measuring apparatus.

  Further, in such alicyclic tetracarboxylic dianhydride monomers, the alicyclic tetracarboxylic dianhydrides represented by the general formulas (7) and (8) (the alicyclic tetracarboxylic acid described above) The total amount (content) of the dianhydrides (A) and (B) may be 90 mol% or more, and may also contain other alicyclic tetracarboxylic dianhydrides. Other alicyclic rings other than the alicyclic tetracarboxylic dianhydrides represented by the general formulas (7) and (8) (the alicyclic tetracarboxylic dianhydrides (A) and (B)) Examples of the formula tetracarboxylic dianhydride include, for example, norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid Other isomers of dianhydrides (isomers other than the isomers represented by the above general formulas (7) and (8)), 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2 1,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6- Tricarboxynorbornane-2-acetic acid dianhydride, 2,3,4,5-tetra Drofurantetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan- 1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan -1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c]- Furan-1,3-dione, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2,2,2] -oct- Alicyclic tetracarboxylic dianhydrides such as 7-ene-2,3,5,6-tetracarboxylic dianhydride , Bicyclo [2,2,1] -heptane-2,3,5,6-tetracarboxylic dianhydride, decahydrodimethanonaphthalene-2,3,6,7-tetracarboxylic dianhydride and the like It is done. As long as the effects of the present invention are not impaired, other monomers other than the alicyclic tetracarboxylic dianhydride may be included in the alicyclic tetracarboxylic dianhydride monomer in the production of the polyimide. Good.

  In addition, a method for producing such an alicyclic tetracarboxylic dianhydride monomer is not particularly limited, and a known method can be appropriately employed. For example, International Publication No. 2014/034760 The described method may be adopted. Moreover, as a suitable method for producing such an alicyclic tetracarboxylic dianhydride monomer, for example, a known method (a method described in International Publication No. 2014/034760, International Publication No. 2011/1, The method described in No. 099517, the method described in International Publication No. 2011/099518, etc.) etc.

Wherein ^{(12), R 1, R} 2, R 3, n are as defined ^{R 1, R 2, R 3} , n in the general formula (1). ]
5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornenes (hereinafter simply referred to as “compound represented by the general formula (12)”) Then, the compound represented by the general formula (12) is converted into a tetracarboxylic dianhydride, and the following general formula (13):

Wherein ^{(13), R 1, R} 2, R 3, n are as defined ^{R 1, R 2, R 3} , n in the general formula (1). ]
Of tetracarboxylic dianhydrides represented by the formula (6 stereoisomers including the alicyclic tetracarboxylic dianhydrides represented by the general formulas (7) and (8) (cis-endo-endo isomers) , Cis-exo-endo isomer, cis-exo-exo isomer, trans-endo-endo isomer, trans-exo-endo isomer, trans-exo-exo isomer)) From the tetracarboxylic dianhydride represented by (13), the alicyclic tetracarboxylic dianhydride represented by the general formulas (7) and (8) (purity is 90 mol% or more) ( A method for obtaining an alicyclic tetracarboxylic dianhydride by separating (separating) the alicyclic tetracarboxylic dianhydrides (A) and (B)), in the general formula (12) Prepare the compound represented before The cis-endo-endo isomer and / or trans-endo-endo isomer is separated and removed from the compound represented by the general formula (12) so that the purity is 90 mol% or more, and this is removed from the tetracarboxylic acid. The total amount of the alicyclic tetracarboxylic dianhydrides (the alicyclic tetracarboxylic dianhydrides (A) and (B)) represented by the general formulas (7) and (8) after dianhydride formation A method for obtaining an alicyclic tetracarboxylic dianhydride monomer containing 90 mol% or more, a compound represented by the general formula (12) is prepared, and the compound represented by the general formula (12) is esterified. Cis-endo-endo isomers and / or tones from the resulting compound (ester or carboxylic acid) after hydrolysis (subsequent hydrolysis treatment or transesterification with carboxylic acid may be used). The alicyclic tetramers represented by the above general formulas (7) and (8) are separated and taken out so that the purity is 90 mol% or more. A method for obtaining an alicyclic tetracarboxylic dianhydride-based monomer containing carboxylic dianhydride (the alicyclic tetracarboxylic dianhydrides (A) and (B)) in a total amount of 90 mol% or more is appropriately used. Can be used.

  A particularly preferable method for converting the compound represented by the general formula (12) into a tetracarboxylic dianhydride to obtain the tetracarboxylic dianhydride represented by the general formula (13) is particularly limited. In addition, a known method capable of dianhydrating these compounds after tetracarboxylic oxidation of the compound represented by the general formula (12) can be appropriately employed. For example, Macromolecules (issued in 1994) 27)), the method described in International Publication No. 2014/034760, the method described in International Publication No. 2011/099517, the method described in International Publication No. 2011/099518, etc. It can be used as appropriate. Further, a method for separating and removing the alicyclic tetracarboxylic dianhydride represented by the general formulas (7) and (8) from the compound represented by the general formula (13), the general formula (12) A method for separating and extracting a cis-endo-endo isomer and / or a trans-endo-endo isomer of the compound from the compound represented by the formula: The method for removing the cis-endo-endo isomer and / or trans-endo-endo isomer from the compound (ester or carboxylic acid) is not particularly limited, and the desired isomer is separated from these compound groups. For example, a recrystallization method (including a crystallization method) or an adsorption separation method may be employed. As such a recrystallization method (including a crystallization method) and an adsorption separation method, for example, a method described in International Publication No. 2014/034760 may be appropriately employed.

Further, with respect to the diamine compound represented by the general formula (9), R ⁴ in the general formula (9) is the same as the R ⁴ in the general formula (1) and (2), the preferred Are the same as those of R ^{4 in} the general formulas (1) and (2). R ⁴ in the general formula (9) may be appropriately changed according to the structure of the target polyimide.

  Examples of the aromatic diamine represented by the general formula (14) include 4,4′-diaminodiphenylmethane, 4,4 ″ -diamino-p-terphenyl, 3,3′-diaminodiphenylmethane, 4 , 4'-diaminodiphenylethane, 3,3'-diaminodiphenylethane, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 2 , 2-bis (4-aminophenoxyphenyl) propane, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, bis [4- (4-aminophenoxy) phenyl ] Sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2′-bis (trifluoromethyl) ) -4,4'-diaminobiphenyl, 3,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 9,9-bis (4-aminophenyl) fluorene, p- Diaminobenzene (also known as p-phenylenediamine), m-diaminobenzene, o-diaminobenzene, 4,4′-diaminobiphenyl, 3,3′-diaminobiphenyl, 2,2′-diaminobiphenyl, 3,4′- Diaminobiphenyl, 2,6-diaminonaphthalene, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 4,4 ′-[1,3-phenylenebis (1-methyl-ethylidene)] bisaniline, 4,4 ′ -[1,4-phenylenebis (1-methyl-ethylidene)] bisaniline, 2,2'-dimethyl-4 4'-diaminobiphenyl (also known as o-tolidine), 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 4,4 ' -Diaminodiphenyl sulfide, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-diaminobenzanilide, 4,4'-diaminophenylbenzoate ( Alias: 4,4′-diaminodiphenyl ester), 9,9′-bis (4-aminophenyl) fluorene, o-tolidine sulfone, 1,3′-bis (4-aminophenoxy) -2,2-dimethylpropane 2,3,5,6-tetramethyl-1,4-phenylenediamine, 3,3 ′, 5,5′-tetramethylbenzidine 1,5-bis (4-aminophenoxy) pentane, diethyltoluenediamine, aminobenzylamine, 1,4-bis-N, N ′-(4′-aminophenyl) terephthalamide, bis (4-aminophenoxy) Examples include terephthalate, bisaniline M, and bisaniline P. It does not restrict | limit especially as a method for manufacturing such an aromatic diamine, A well-known method is employable suitably. Moreover, you may use a commercially available thing suitably as such aromatic diamine.

In addition, from the viewpoint that the linear expansion coefficient of the obtained polyimide can be set to a lower value within the range of the above numerical values, R ^{4 of the} aromatic diamine represented by the general formula (9) is represented by the general formula: More preferably, it is a group represented by (5) or (6), and among them, a group represented by the general formula (5), and a group represented by the general formula (6) and Q is -CONH-, At least one group represented by —COO—, —CO—, —C ₆ H ₄ — (more preferably a group represented by —CONH—, —COO—, particularly preferably —CONH—; It is preferable that the group is a group represented by: In addition, when a film is formed from the obtained polyimide, R ^{4 of the} aromatic diamine represented by the general formula (9) is represented by the general formula (3) from the viewpoint of imparting higher flexibility. And Q is one of the groups represented by —O—, —S—, —CH ₂ —, —O—C ₆ H ₄ —O—. The group represented by 6) is preferably one group selected from the group consisting of: From the viewpoint of availability, R ^{4 of the} aromatic diamine represented by the general formula (9) has the above Q as —O—, —CH ₂ —, —O—C ₆ H ₄ —O—, One of groups represented by —O—C ₆ H ₄ —C ₆ H ₄ —O— (more preferably —O—, —CH ₂ —, —O—C ₆ H ₄ —C ₆ H ₄ It is preferable that it is group represented by the said General formula (6) which is 1 type in the group represented by -O-, More preferably, it is group represented by -O-.

Further, as the aromatic diamine represented by the general formula (9), the glass transition temperature and the linear expansion coefficient of polyimide can be set within the ranges of the above preferable numerical values, and the glass transition temperature and the linear expansion can be obtained. From the viewpoint of more reliably preparing a polyimide that can exhibit a good balance between the coefficient and the flexibility when a film is formed, a plurality of different types of R ^{4 in} the general formula (14) are used. It is preferable to use a combination of two or more aromatic diamines. From the same viewpoint, since higher effects can be obtained, wherein the aromatic diamine of plural kinds of different R ⁴ are different (two or more), R ⁴ is the general in the general formula (14) groups represented by the formula (5); and wherein Q is -CONH -, - COO -, - CO -, - C 6 H 4 - at least one of a group represented by (more preferably -CONH- A group represented by the general formula (6) which is a group represented by -COO-, particularly preferably a group represented by -CONH-; Group diamine and R ⁴ in the general formula (14) is a group represented by the general formula (3); and the Q is —O—, —S—, —CH ₂ —, —O—C _{6. H 4 -O -, - O-} C 6 H 4 -C 6 H 4 1 kind of -O-, a group represented by (more preferably - _{-, - CH 2 -, -} O-C 6 H 4 -C 6 H 4 1 kind of -O-, a group represented by the further the general formula is preferably represented by -O- groups) It is more preferable to contain at least an aromatic diamine that is one group selected from the group consisting of the group represented by (6).

  Moreover, the said alicyclic tetracarboxylic dianhydride (A) and (B) are contained, and the total amount (content) of the said alicyclic tetracarboxylic dianhydride (A) and (B) is all alicyclic. 90 mol% or more of the alicyclic tetracarboxylic dianhydride monomer (polyimide-forming monomer) with respect to the formula tetracarboxylic dianhydride, and the aromatic diamine represented by the general formula (9) In the reaction, it is preferable to use an organic solvent. That is, as a step for obtaining such polyamic acid, in the presence of an organic solvent, among the alicyclic tetracarboxylic dianhydride (A) and the alicyclic tetracarboxylic dianhydride (B) And an alicyclic tetracarboxylic dianhydride-based monomer in which the total amount of the alicyclic tetracarboxylic dianhydrides (A) and (B) is 90 mol% or more, and The aromatic diamine represented by the general formula (9) is reacted to contain at least one repeating unit represented by the general formulas (10) and (11), and the general formulas (10) and (11 The step of forming a polyamic acid in which the total amount of repeating units represented by) is 90 mol% or more to obtain a polyamic acid solution containing the polyamic acid is preferred. As such an organic solvent, it is possible to dissolve both the alicyclic tetracarboxylic dianhydride monomer (polyimide-forming monomer) and the aromatic diamine represented by the general formula (9). A possible organic solvent is preferred. Furthermore, as such an organic solvent, for example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, N, N′-dimethylimidazole, dimethyl sulfoxide, γ-butyrolactone, propylene Aprotic polar solvents such as carbonate, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphoric triamide, pyridine; phenolic solvents such as m-cresol, xylenol, phenol, halogenated phenol Ether solvents such as tetrahydrofuran, dioxane, cellosolve and glyme; aromatic solvents such as benzene, toluene, xylene and 2-chloro-4-hydroxytoluene; halogen solvents such as methylene chloride, chloroform and carbon tetrachloride ;But It is below. Such organic solvents may be used singly or in combination of two or more.

  In addition, when the alicyclic tetracarboxylic dianhydride monomer (polyimide-forming monomer) is reacted with the aromatic diamine represented by the general formula (9), the alicyclic tetracarboxylic dianhydride is used. The use ratio of the anhydride monomer (monomer for forming polyimide) and the aromatic diamine represented by the general formula (9) is the amino group 1 of the aromatic diamine represented by the general formula (9). It is preferable that the acid anhydride group of the alicyclic tetracarboxylic dianhydride monomer (polyimide-forming monomer) is 0.2 to 2 equivalents with respect to equivalents, and 0.3 to 1.2 equivalents. More preferably. If the use ratio is less than the lower limit, the polymerization reaction does not proceed efficiently, and a high molecular weight polyamic acid tends not to be obtained. On the other hand, if the upper limit is exceeded, a high molecular weight polyamic acid is obtained as described above. There is no tendency.

  In the reaction of the alicyclic tetracarboxylic dianhydride monomer (polyimide-forming monomer) with the aromatic diamine represented by the general formula (9), the ratio of these used is the molar ratio ([ Cycloaliphatic tetracarboxylic dianhydride monomer]: [aromatic diamine]) 0.5: 1.0 to 1.0: 0.5 (more preferably 0.9: 1.0 to 1.0). : 0.9). If the amount of the alicyclic tetracarboxylic dianhydride monomer (polyimide-forming monomer) used is less than the lower limit, the yield of the polyimide tends to decrease. The yield tends to decrease.

  Furthermore, when making it react in presence of an organic solvent, as the usage-amount of the said organic solvent, it represents with the said alicyclic tetracarboxylic dianhydride type monomer (monomer for polyimide formation), and the said General formula (9). It is preferable that the total amount of the aromatic diamine is 0.1 to 50% by mass (more preferably 10 to 30% by mass) with respect to the total amount of the reaction solution. If the amount of such an organic solvent used is less than the lower limit, it tends to be difficult to obtain a polyamic acid efficiently.

  Moreover, when making it react in presence of an organic solvent, the said alicyclic tetracarboxylic dianhydride type monomer (monomer for polyimide formation) and the aromatic diamine represented by the said General formula (9) are made to react. At this time, a base compound may be further added to the organic solvent from the viewpoint of improving the reaction rate and obtaining a polyamic acid having a high degree of polymerization. The basic compound is not particularly limited, and examples thereof include triethylamine, tetrabutylamine, tetrahexylamine, 1,8-diazabicyclo [5.4.0] -undecene-7, pyridine, isoquinoline, N-methylpiperidine, α-picoline and the like can be mentioned. The amount of such a base compound used is preferably 0.001 to 10 equivalents per 1 equivalent of the alicyclic tetracarboxylic dianhydride monomer (polyimide-forming monomer). More preferably, the content is 0.01 to 0.1 equivalent. If the amount of such a basic compound used is less than the lower limit, the effect of addition tends to be lost. On the other hand, if it exceeds the upper limit, it tends to cause coloring or the like.

  The reaction temperature for reacting the alicyclic tetracarboxylic dianhydride monomer (polyimide-forming monomer) with the aromatic diamine represented by the general formula (9) reacts with these compounds. The temperature can be appropriately adjusted to a temperature that can be adjusted, and is not particularly limited. Further, as a method for reacting the alicyclic tetracarboxylic dianhydride monomer (polyimide-forming monomer) with the aromatic diamine represented by the general formula (9), tetracarboxylic dianhydride is used. A method capable of carrying out the polymerization reaction of the product with the aromatic diamine can be used as appropriate, and is not particularly limited. Alternatively, the alicyclic tetracarboxylic dianhydride monomer (polyimide-forming monomer) may be added at the reaction temperature, and then reacted for 10 to 48 hours. If the reaction temperature or reaction time is less than the lower limit, it tends to be difficult to cause sufficient reaction. On the other hand, if the upper limit is exceeded, the probability of mixing a substance (such as oxygen) that degrades the polymer increases and the molecular weight increases. It tends to decrease.

  In this way, by reacting the alicyclic tetracarboxylic dianhydride monomer (polyimide-forming monomer) with the aromatic diamine represented by the general formula (9), the general formula (10 ) And (11) at least one type of repeating unit, and the total amount of the repeating units represented by the general formulas (10) and (11) is 90 mol% or more.

Incidentally, in the general formula (10) and ^{(11), R 1, R} 2, R 3, n has the same meaning as ^{R 1, R 2, R 3} , n in the general formula (7), R ⁴ has the same meaning as R ⁴ in formula (9). That, ^R 1 in the general formula (10) and ^(11), R ^2, R 3, ^R 1 ^{R 4} and n are the general formula (1) and (2) ^in, R ^{2, R} 3, R ⁴ and n are the same as those described above, and suitable ones thereof are also the same as R ¹ , R ² , R ³ , R ⁴ and n in the general formulas (1) and (2).

  Further, such polyamic acid has a total amount of repeating units represented by the general formulas (10) and (11) of 90 mol% or more. The total amount of such repeating units is the alicyclic tetracarboxylic acid represented by the general formulas (7) and (8) in the alicyclic tetracarboxylic dianhydride monomer (polyimide-forming monomer). It is derived from the total amount of the dianhydride, and the preferable range of the total amount is the same as the preferable range of the total amount of the alicyclic tetracarboxylic dianhydride represented by the general formulas (7) and (8). It is. If the total amount of the repeating units represented by the general formulas (10) and (11) is less than 90 mol%, it is impossible to produce a film made of the polyimide of the present invention.

  Moreover, as a polyamic acid used at such a process (I), it is preferable that intrinsic viscosity [(eta)] is 0.1-8.0 dL / g, and it is 0.1-6.0 dL / g. Is more preferably 0.1 to 3.0 dL / g, and particularly preferably 0.4 to 2.0 dL / g. When the intrinsic viscosity [η] is smaller than 0.1 dL / g, when a film-like polyimide is produced using the intrinsic viscosity [η], the resulting film tends to become brittle, while 8.0 dL / g is reduced. When it exceeds, the viscosity is too high and the processability is lowered, and for example, when a film is produced, it is difficult to obtain a uniform film. Such intrinsic viscosity [η] can be measured as follows. That is, first, a measurement sample (solution) in which N, N-dimethylacetamide is used as a solvent and the polyamic acid is dissolved in the N, N-dimethylacetamide so as to have a concentration of 0.5 g / dL. obtain. Next, using the measurement sample, the viscosity of the measurement sample is measured using a kinematic viscometer under a temperature condition of 30 ° C., and the obtained value is adopted as the intrinsic viscosity [η]. In addition, as such a kinematic viscometer, an automatic viscosity measuring apparatus (trade name “VMC-252”) manufactured by Koiso Co., Ltd. is used.

  The polyamic acid solution containing the polyamic acid is composed of the polyamic acid and a solvent. Such a solvent is not particularly limited, and the same organic solvent (organic solvent that can be used in the step for obtaining polyamic acid) can be suitably used. The method for preparing the polyamic acid solution containing such polyamic acid is not particularly limited. For example, after obtaining the polyamic acid by the above reaction and isolating it, the solvent ( For example, the polyamic acid solution may be obtained by dissolving in the organic solvent or the like, or the alicyclic tetracarboxylic dianhydride monomer (monomer for forming polyimide) and the general formula in the organic solvent. After the polyamic acid is formed by reacting with the aromatic diamine represented by (9), the obtained reaction solution (the reaction solution containing the polyamic acid) is used as it is without isolating the polyamic acid. A polyamic acid solution may be used. When the polyamic acid is isolated from the reaction solution and used, the isolation method is not particularly limited, and a known method capable of isolating the polyamic acid can be appropriately employed. For example, a method of isolating as a reprecipitate may be employed.

  Moreover, the content of the polyamic acid in the polyamic acid solution is not particularly limited, but is preferably 1 to 80% by mass, and more preferably 5 to 50% by mass. When the content of such polyamic acid is less than the lower limit, the physical properties of the film obtained by lowering the molecular weight of the resulting polyimide (glass transition temperature, 5% weight loss temperature, softening temperature, tensile strength, breaking elongation, elasticity Rate, linear expansion coefficient, transmittance, haze, yellowness, retardation, etc.) tend to be reduced, and on the other hand, when the upper limit is exceeded, it tends to be difficult to produce a polyimide film.

  In addition, in the polyimide which forms the 1st film obtained by process (I), you may contain other repeating units other than the repeating unit represented by the said General formula (1) and (2), In that case, the other repeating unit is, for example, an alicyclic tetracarboxylic dianhydride represented by the general formulas (7) and (8) in the alicyclic tetracarboxylic dianhydride monomer. May be formed by introducing other tetracarboxylic dianhydride other than the above, may be formed by using other monomers together with the alicyclic tetracarboxylic dianhydride monomer, and A method using another diamine compound together with the aromatic diamine represented by the general formula (9) may be adopted, and further, these methods may be adopted in combination as appropriate.

  Other than the alicyclic tetracarboxylic dianhydrides represented by the general formulas (7) and (8) that can be introduced into the alicyclic tetracarboxylic dianhydride monomers (polyimide-forming monomers). As other monomers that can be used together with the alicyclic tetracarboxylic dianhydride of the present invention and the alicyclic tetracarboxylic dianhydride of the present invention, fats represented by the above general formulas (7) and (8) Compounds represented by the above general formula (13) other than cyclic tetracarboxylic dianhydride (other isomers), butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3 , 5,6-Tricarboxyno Lubornane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo- 3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-methyl-5- (tetrahydro-2,5-dioxo -3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5- Dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic Acid dianhydride, bicyclo [2,2,2] -oct-7-ene-2,3,5,6-tetraca Aliphatic or alicyclic tetracarboxylic dianhydrides such as rubonic acid dianhydride; pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′ , 4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3 ', 4,4'-dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3', 4,4'-tetraphenylsilane tetracarboxylic Acid dianhydride, 1,2,3,4-furantetracarboxylic dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3 , 4-Dicarboxyphenoxy) diphenyls Lufone dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidenediphthalic dianhydride, 4,4 '-(2,2-hexafluoroisopropylidene) diphthalic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride, 2,3,3 ', 4'-biphenyltetracarboxylic acid Dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenyl) Aromatic tetracarboxylic dianhydrides such as phthalic acid) -4,4′-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4′-diphenylmethane dianhydride, and the like. It is. In addition, when using aromatic tetracarboxylic acid, in order to prevent coloring by intramolecular CT, the amount used thereof is appropriately changed within a range in which the obtained polyimide can have sufficient transparency. It is preferable.

  Moreover, it does not restrict | limit especially as other diamine compounds other than the said aromatic diamine, The well-known diamine compound which can be used for manufacture of a polyimide or a polyamic acid can be used suitably, for example, aliphatic diamine, An alicyclic diamine or the like can be used as appropriate. Examples of such aliphatic diamines include ethylene diamine, propylene diamine, trimethylene diamine, tetramethylene diamine, hexamethylene diamine, and polyoxyalkylene diamine. Examples of the alicyclic diamine include 4,4′-diamino-dicyclohexylmethane, 3,3′-dimethyl-4,4′-diamino-dicyclohexylmethane, and 3,3′-diethyl-4,4′-. Diamino-dicyclohexylmethane, 3,3 ′, 5,5′-tetramethyl-4,4′-diamino-dicyclohexylmethane, 3,3 ′, 5,5′-tetraethyl-4,4′-diamino-dicyclohexylmethane, 3,5-diethyl-3 ′, 5′-dimethyl-4,4′-diaminodicyclohexylmethane, bis (aminomethyl) cyclohexane, 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, bicyclo [2.2. 1] heptanedimethanamine, norbornanediamine and the like.

  Next, using such a polyamic acid solution, a first composed of polyimide having a total amount of repeating units represented by the general formulas (1) and (2) of 90 mol% or more based on all repeating units. The process of obtaining a film will be described.

  The step of obtaining the first film using the polyamic acid solution is not particularly limited, but after the polyamic acid solution is applied on a substrate to form a coating film, By imidizing the polyamic acid and curing the coating film, it contains at least one of the repeating units represented by the general formulas (1) and (2), and the general formulas (1) and ( It is preferable to employ the step (a) of obtaining a first film made of polyimide in which the total amount of the repeating units represented by 2) is 90 mol% or more based on all repeating units.

  The base material used in such a step (a) is not particularly limited, and a base material made of a known material that can be used to form a film (for example, depending on the shape of the target film made of polyimide, for example) Glass plate or metal plate) can be used as appropriate.

  Further, in the step (a), the method for applying the polyamic acid solution or the like on the substrate is not particularly limited. For example, a spin coating method, a spray coating method, a dip coating method, a dropping method, a gravure printing method, Known methods such as a screen printing method, a relief printing method, a die coating method, a curtain coating method, and an ink jet method can be appropriately employed.

  In the step (a), the thickness of the polyamic acid coating film formed on the substrate is preferably 1 to 200 μm after drying, and preferably 5 to 100 μm. It is more preferable that If such a thickness is less than the lower limit, the mechanical strength of the resulting film tends to decrease, and if it exceeds the upper limit, film forming tends to be difficult.

  Moreover, in the step (a), after forming the coating film, in some cases, a treatment for removing the solvent from the coating film may be performed. Thus, although it does not restrict | limit especially as temperature conditions in performing the process (solvent removal process) which removes a solvent from the said coating film, It is preferable that it is 0-100 degreeC, and it is 20-80 degreeC. More preferred. If the temperature condition in such a solvent removal process is less than the lower limit, the solvent tends not to evaporate. On the other hand, if the temperature condition exceeds the upper limit, the solvent tends to boil and form a film containing bubbles and voids. Further, the atmosphere in such a drying treatment method is preferably an inert gas atmosphere (for example, a nitrogen atmosphere). Further, from the viewpoint of performing the solvent removal process more efficiently, the pressure condition in such a solvent removal process is preferably 1 to 760 mmHg. By such a solvent removal treatment, the polyamic acid can be isolated in the form of a film or the like, and then a solvent removal treatment can be performed.

  In the step (a), the method for imidizing the polyamic acid in the coating film may be any method that can imidize the polyamic acid, and is not particularly limited, and a known method can be appropriately employed. For example, it is preferable to employ a method of imidizing by performing a dehydration reaction by subjecting the polyamic acid to a heat treatment, or a method of imidizing using a so-called “imidizing agent”.

  As described above, in the case of adopting a method of performing a dehydration reaction by performing a heat treatment as a method of imidization of a polyamic acid (a method of imidizing by performing a heat treatment), 200 to 450 ° C. (preferably 250 to It is preferable to perform the heat treatment under a temperature condition of 440 ° C, more preferably 300 to 430 ° C, still more preferably 350 to 420 ° C, particularly preferably 360 ° C to 410 ° C. In the case of adopting a method of imidizing by performing such a heat treatment and performing a dehydration reaction, when the heating temperature is less than 200 ° C., the polyamic acid is dehydrated and cyclized, and the reaction with the acid dianhydride rather than the reaction to become a polyimide. Equilibrium reactions that decompose into amines tend to be advantageous. On the other hand, when the upper limit is exceeded, coloring tends to occur and molecular weight decreases due to thermal decomposition.

  In addition, in the case of adopting a method of imidizing by performing heat treatment in the step (a), the alicyclic tetratetrahydrochloride in the organic solvent without isolating the polyamic acid in the step (I). A reaction liquid (reaction liquid containing the polyamic acid) obtained by reacting a carboxylic acid dianhydride monomer (monomer for polyimide formation) with the aromatic diamine represented by the general formula (14) By using the polyamic acid solution for imidization as it is, subjecting the polyamic acid solution (reaction solution) to the above solvent removal treatment to remove the solvent, and then subjecting it to a heat treatment in the above temperature range. It is preferable to employ a method of imidization.

  In the step (a), when a method of imidizing using a so-called “imidating agent” is employed, it is preferable to imidize in the solution of the polyamic acid in the presence of the imidizing agent. As the solvent of such a solution, the organic solvent described in the step (I) can be preferably used. Therefore, in the case of employing the imidization method using an imidizing agent, the alicyclic tetracarboxylic acid dicarboxylic acid is obtained in an organic solvent without isolating the polyamic acid obtained in the step (I). Imide the reaction liquid (reaction liquid containing the polyamic acid) obtained by reacting the anhydride monomer (monomer for forming polyimide) with the aromatic diamine represented by the general formula (9). It is more preferable to employ a method in which an imidizing agent is added to the polyamic acid solution (reaction solution) and imidized.

  As such an imidizing agent, a known imidizing agent can be appropriately used. For example, acid anhydrides such as acetic anhydride, propionic anhydride, trifluoroacetic anhydride; pyridine, collidine, lutidine, triethylamine, N -Tertiary amines such as methylpiperidine and β-picoline;

  Moreover, when adding an imidizing agent and imidating, it is preferable that the reaction temperature of imidation is 0-180 degreeC, and it is more preferable that it is 60-150 degreeC. The reaction time is preferably 0.1 to 48 hours. If the reaction temperature or time is less than the lower limit, it tends to be difficult to sufficiently imidize. On the other hand, if the upper limit is exceeded, the mixing probability of a substance (such as oxygen) that degrades the polymer increases, and the molecular weight increases. It tends to decrease. In addition, the amount of such an imidizing agent is not particularly limited, and is from several millimoles to several mols per mol of the repeating unit represented by the general formulas (10) and (11) in the polyamic acid ( Preferably, about 0.05 to 1.0 mol) may be used.

  Thus, after imidating the polyamic acid in the coating film, the coating film is cured, thereby containing at least one repeating unit represented by the general formulas (1) and (2) and A first film of polyimide in which the total amount of the repeating units represented by the general formulas (1) and (2) is 90 mol% or more based on all repeating units can be suitably obtained.

  Thus, the method for curing the coating film after imidation is not particularly limited, but is a temperature in the vicinity of the glass transition temperature of the polyimide obtained by imidization (more preferably glass transition temperature ± 40 ° C., more preferably glass transition temperature). It is preferable to adopt a method (heat curing) of heating at ± 20 ° C., particularly preferably glass transition temperature ± 10 ° C., for 0.1 to 10 hours (preferably 0.5 to 2 hours). If the heating temperature and time are less than the lower limit, the solid phase polymerization reaction does not proceed sufficiently and the film tends to be brittle and weak. It tends to happen. In addition, the atmosphere at the time of such heat curing is preferably an inert gas atmosphere (for example, a nitrogen atmosphere), and the pressure condition at the time of heat curing is preferably 0.01 to 760 mmHg. More preferably, it is 0.01 to 200 mmHg. In addition, you may perform the heat processing for imidation, and the heat processing for subsequent heat-curing as a series of heat processing, In this case, the heating temperature in the above-mentioned imidation WHEREIN: It is preferable to carry out the heat treatment continuously at a constant temperature as the temperature within the temperature range employed for curing. That is, a film can also be obtained by curing the coating as it is after imidation by a series of heat treatments (imidation and heat curing are combined into one heat treatment). In addition, if the reaction solution obtained in step (I) is applied as it is on a substrate (for example, a glass plate) and the method for removing the solvent and the heat treatment is adopted, a film made of polyimide can be obtained by a simple method. It becomes possible to manufacture a precursor (precursor of the polyimide film of the present invention).

  In addition, in the step of obtaining the first film using the polyamic acid solution, in addition to the step (a), for example, the method described in the step (a) described above is used to apply a cured coating on the substrate. A polyimide obtained as a film; or a polyimide solution obtained by imidization by adding an imidizing agent to a polyamic acid solution without forming a coating film; After adding polyimide in a poor solvent, and performing filtration, washing, drying, etc. as appropriate, the polyimide is isolated, and then the isolated polyimide is dissolved in an organic solvent to prepare a polyimide solution. After applying the solution to the substrate to form a coating film, the solvent removal treatment is performed, and then the polyimide coating film is heated and cured to obtain a first film (film precursor) (b) Preferably It can be. In addition, as a base material used in such a step (b), a method of imidation, a method of heat curing, etc., the base material described in step (a), a method of imidization, a method of heat curing, etc. The same thing, the same method, etc. can be utilized suitably.

  Moreover, in the said process (b), although it does not restrict | limit especially as a solvent with the poor solubility of this polyimide used when isolating the said polyimide, For example, methanol, ethanol, isopropanol, acetone, ethyl acetate, hexane, toluene etc. Can be used. In addition, as the solvent of the polyimide solution in the step (b), the same solvent as that of the polyamic acid solution described above can be used, and furthermore, the polyimide solution applied in the step (b) can be used. As the method for the solvent removal treatment of the film, the same method as the solvent removal treatment method for the coating film of the polyamic acid solution described in the above step (a) can be employed.

  Thus, the polyimide obtained by imidating the said polyamic acid by implementing the process (a) or the process (b) which can be utilized suitably as a process of obtaining a 1st film using the said polyamic acid solution. The 1st film (precursor of the polyimide film of this invention) which consists of (1st polyimide) can be obtained suitably.

(Step (II): Step of obtaining a polyimide film (second film))
Next, process (II) is demonstrated. In step (II), the first film is stretched in an inert gas atmosphere at an atmospheric temperature of 370 to 450 ° C. so that the stretch ratio is 1.0001 to 1.050. In this step, a second film is formed to obtain a polyimide film (second film).

  In the step (II), the gas atmosphere when performing the step of stretching the first film (stretching step) needs to be an inert gas atmosphere. When heated at the above atmospheric temperature in a gas atmosphere other than an inert gas atmosphere, the resulting polyimide film (second film) is oxidized and colored. In addition, the inert gas atmosphere here refers to a gas atmosphere containing an inert gas and having an oxygen content of less than 20 ppm. Examples of such an inert gas include nitrogen and argon.

  Moreover, in the said extending process, it is necessary to extend | stretch said 1st film on the conditions of 370-450 degreeC atmospheric temperature. The “atmospheric temperature” here refers to the highest temperature among the temperatures of the atmosphere measured when the stretching process is performed. For example, when the stretching process is performed while gradually raising the temperature, the maximum temperature reached while the first film is being stretched is the aforementioned “atmosphere temperature”, and when stretching under uniform temperature conditions, When the stretching is performed while appropriately changing the temperature, the maximum temperature among the temperatures of the atmosphere measured at the stretching is the above-mentioned “atmospheric temperature”. If the atmospheric temperature is lower than the lower limit, the film cannot be stretched and the desired linear expansion coefficient tends not to be achieved.On the other hand, if the upper limit is exceeded, the thermal decomposition of the film proceeds and causes deterioration of physical properties and coloring. Become. From the same viewpoint, the atmospheric temperature in the stretching step is preferably 375 to 440 ° C. (the upper limit of the atmospheric temperature is more preferably 430 ° C., and still more preferably 420 ° C.). From the viewpoint of workability and the like, the temperature is more preferably 370 to 400 ° C. By adopting such an atmospheric temperature within a suitable temperature range, it becomes possible to control the linear expansion coefficient to a desired value without lowering the physical properties or coloring of the film.

  In the present invention, it is necessary to stretch the first film so that the stretching ratio is 1.0001 to 1.050. When such a draw ratio is less than the lower limit, it becomes difficult to control the linear expansion coefficient to a desired value, and tends to cause a decrease in strength, a decrease in elastic modulus, and a decrease in creep characteristics, If the upper limit is exceeded, the film tends to be broken, waved, whitened, or spotted. Further, from the same viewpoint, such a draw ratio is preferably 1.0005 to 1.040 times, more preferably 1.0008 to 1.035 times. It is more preferable that the ratio is ˜1.030 times. In addition, it becomes possible to control a linear expansion coefficient to a desired value by stretching the first film within the range of such a suitable stretching ratio, and it is more sophisticated in terms of smoothness and uniformity. It tends to be effective. The stretch ratio here is the ratio of the length of the film after stretching to the length of the film before stretching at room temperature (25 ° C.) ([length of film after stretching] / [length of film before stretching]. Length]). When a part of the film is stretched (for example, when a part is fixed and the other part of the film is stretched), the stretch ratio is the length of the stretched part of the film before stretching (stretching) The ratio of the length of the stretched part to the fixed part (the length of the film excluding the gripping part when the film is fixed by gripping) is adopted. That is, excluding the length of the portion not involved in stretching, the stretch ratio is determined by the ratio of the length before stretching and the length after stretching of the portion involved in stretching.

  In addition, the specific method of stretching is not particularly limited except that the conditions of the gas atmosphere, the atmospheric temperature, and the stretching ratio need to be satisfied, and a conventionally known stretching method can be appropriately employed. For example, a radiation stretching method, a hot air heating method, a hot plate heating method, a roll heating method, or the like may be used. Further, as such a stretching step, it is preferable to stretch in a certain direction from the viewpoint of forming a sufficient orientation in a predetermined direction, and so-called uniaxial stretching may be used. In addition, as the stretching here, it is basically desirable to stretch in one direction from the viewpoint of forming a sufficient orientation in a predetermined direction, but a film that can be produced in such stretching in one direction. In order to eliminate the deflection of the film, such stretching in one direction (for example, Machine Direction (machine direction): film flow direction: stretching in the MD direction) and a direction other than the stretching direction (for example, Transverse Direction (transformer) (Birth direction): width direction of film: TD direction), and in order to eliminate inconveniences such as deflection, a process of stretching in other directions or annealing may be performed. These may be performed simultaneously or sequentially. Further, the stretching operation may be carried out continuously or batchwise. The stretching device may be a transverse stretching device (transverse stretching device) or a longitudinal stretching device (longitudinal stretching device).

  In the present invention, after the stretching step is completed, the stretched film is cooled to a temperature at which the physical properties do not change (temperature at which the orientation state of the polymer chain is fixed; glass transition temperature or lower or softening point temperature or lower). Later, it may be used for other applications (for example, used for other processes such as a process for producing an inorganic layer when manufacturing a product), or it may remain at the stretching temperature for efficient use in other applications. You may convey and use (it may convey with a extending | stretching temperature and may perform another process). Depending on the application, if there is no need to transport at the stretching temperature to other processes (for example, the process of manufacturing an inorganic layer when manufacturing products), a method of cooling to a temperature at which the physical properties do not change is adopted. It is common to do. In this case, in order to fix the orientation state of the stretched polymer chain, the temperature drop temperature is appropriately adjusted, and the glass transition temperature or lower or softening temperature or lower (more than It is preferable to cool to a softening point of −10 ° C. Thus, in the above cooling method, the temperature at which the physical properties of the film do not change (cooling temperature) varies depending on the type of polyimide. For example, the temperature is lower than the glass transition temperature, or the polyimide is softened. The temperature is equal to or lower than the temperature (more preferably, the temperature is equal to or lower than the softening temperature of the polyimide by 10 ° C. or lower ([softening temperature−10) ° C. or lower]). In addition, after stretching, the film may be cooled by natural cooling.

  Thus, by performing an extending | stretching process, the polyimide film which consists of the polyimide (2nd polyimide) after extending | stretching can be obtained. In such a stretching process, the structure of the polyimide in the first film before stretching changes from a structure with insufficient orientation to a structure with sufficient orientation, and a new structure of polyimide. (Polyimide after stretching: second polyimide) Therefore, in the polyimide film (finally obtained film) consisting of the second film (film after stretching) obtained, the linear expansion coefficient at high temperature is sufficient. The present inventors speculate that it can be made low.

  The polyimide film thus obtained (polyimide film after stretching: second film) has a linear expansion coefficient of 350 ° C. in the longitudinal direction (stretching direction) of 10 ppm / ° C. or less and is increased in a nitrogen atmosphere. It becomes a film made of polyimide having an average linear expansion coefficient of 15 ppm / ° C. or less obtained by measuring a change in length in a temperature range of 50 ° C. to 400 ° C. under a temperature rate of 5 ° C./min. Thus, according to the method for producing a polyimide film of the present invention, the polyimide of the present invention can be produced more efficiently and reliably. In addition, the polyimide film thus obtained is sufficiently high in transparency and heat resistance, and has a sufficiently low linear expansion coefficient at high temperature, resulting in thermal shock (change in ambient temperature). ) With sufficiently high tolerance. Therefore, the polyimide film (polyimide film as the second film) obtained by the present invention has not only sufficiently high transparency but also sufficiently high heat resistance and an extremely low linear expansion coefficient, and is a solar cell. Even when used for the manufacture of products such as display devices and the like, the film is sufficiently suppressed from being cracked or cracked even when exposed to high temperatures during the manufacturing process. Accordingly, the polyimide film is, for example, a flexible wiring substrate, a transparent electrode substrate (for example, a substrate film for laminating a transparent electrode of a touch panel or a solar cell, a transparent device such as an organic EL display device or a liquid crystal display device). In addition to films used for applications such as a substrate film for laminating electrodes), FPC (flexible printed circuit board), optical waveguide, image sensor, LED reflector, LED illumination cover, skeleton type FPC, coverlay film, Films used for applications such as chip-on-films, high-ductility composite substrates, liquid crystal alignment films, polyimide coating materials (buffer coating materials for DRAMs, flash memories, next-generation LSIs, etc.), semiconductor resists, lithium-ion batteries, and various electrical materials , Touch panel substrate, organic L display substrate, is particularly useful organic EL illumination substrate, the water vapor barrier film substrate, the air barrier film substrate, an organic memory substrates, an organic transistor substrate, an organic semiconductor substrate, as a copying machine belt or the like.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

  First, the evaluation method of the characteristics (linear expansion coefficient etc.) of the polyimide which forms the film obtained by each Example and each comparative example is demonstrated.

<Measurement of linear expansion coefficient>
Each linear expansion coefficient (average linear expansion coefficient in a temperature range of 50 ° C. to 400 ° C., average linear expansion coefficient in a temperature range of 50 ° C. to 200 ° C., and linear expansion coefficient of 350 ° C.) was measured as follows. That is, first, a measurement sample precursor (film) having a size of 20 mm in length, 5 mm in width, and 0.013 mm (13 μm) in thickness was formed from the polyimide films obtained in Examples 1 to 6 and Comparative Examples 1 to 4, respectively. did. In forming the measurement sample precursor, the longitudinal direction of the polyimide film before forming the measurement sample precursor (the stretching direction in Examples 1 to 6 and Comparative Example 4) is the longitudinal direction of the measurement sample precursor. It was. Next, the measurement sample precursor (film) was vacuum-dried (120 ° C., 1 hour (Hr)), and heat-treated at 200 ° C. for 1 hour (Hr) in a nitrogen atmosphere. Film). Thereafter, using a thermomechanical analyzer (trade name “TMA8310” manufactured by Rigaku Corporation) as a measuring device, under a nitrogen atmosphere, using a tension mode (49 mN), a temperature rising rate of 5 ° C./min, 50 The change in the length of the measurement sample at a temperature ranging from 0C to 400C was measured continuously.

  First, based on the data obtained by the measurement (measurement data: data on the change in length of the measurement sample), the average change in length per 1 ° C. in the temperature range of 50 ° C. to 400 ° C. The average linear expansion coefficient in the temperature range of 50 ° C. to 400 ° C. was obtained by calculating and obtaining the value. Next, using the measurement data, a value of a change in length of the sample in the longitudinal direction per 1 ° C. in a temperature range of 349 ° C. to 351 ° C. is obtained, and 1 in a temperature range of 349 ° C. to 351 ° C. The average value of the change in length per ° C was calculated to determine the linear expansion coefficient at 350 ° C. In addition, the average value (average linear expansion coefficient in the temperature range of 50 ° C. to 200 ° C.) of the length change per 1 ° C. in the temperature range of 50 ° C. to 200 ° C. determined based on the measurement data was also obtained. .

<Measurement of softening temperature>
The softening temperature of the polyimide forming the film obtained in Example 1 and Comparative Example 1 was measured as follows. That is, a film made of polyimide having a size of 5 mm in length, 5 mm in width and 0.013 mm (13 μm) in thickness was prepared as a measurement sample, and a thermomechanical analyzer (trade name “TMA8311” manufactured by Rigaku) was used as a measurement device. The film was measured by inserting a transparent quartz pin (tip diameter: 0.5 mm) into the film under a nitrogen atmosphere under conditions of a temperature rising rate of 5 ° C./min and a temperature range of 30 ° C. to 550 ° C. (so-called penetration ( In such measurement, the softening temperature was calculated based on the measurement data in accordance with the method described in JIS K 7196 (1991) except that the above measurement sample was used. .

<Measurement of 5% weight loss temperature>
The 5% weight reduction temperature of the polyimide forming the film obtained in Example 1 and Comparative Example 1 was prepared by preparing five film-shaped samples each having a length of 2 mm, a width of 2 mm, and a thickness of 50 μm. Put in a pan and use a TG / DTA7200 thermogravimetric analyzer (SII Nano Technology Co., Ltd.) as the measuring device, and flow 10 ° C / min in the range of room temperature (25 ° C) to 600 ° C while flowing nitrogen gas. The temperature was determined by measuring the temperature at which the weight of the sample used was reduced by 5%.

<Measurement of stretch ratio>
The stretching ratio in the stretching process employed in each example and each comparative example is the length before stretching in the longitudinal (stretching) direction excluding the grip allowance portion (for 10 mm length) at room temperature (25 ° C.) (the following calculation formula ( I)), and the length in the longitudinal (stretching) direction after stretching excluding the gripping portion (shown as “L2” in the following formula (I)) is measured. Formula (I):
[Stretch ratio] = [L2] / [L1] (I)
Calculated by That is, excluding the length of the portion not involved in stretching, the stretch ratio was determined from the ratio of the length before and after stretching of the portion involved in stretching.
Example 1
<Preparation process of alicyclic tetracarboxylic dianhydride monomer>
First, in accordance with the monomer synthesis step of Example 1 of International Publication No. 2014/034760, the following general formula (14):

Trans, endo, endo-norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic dianhydride And the following general formula (15):

Cis, endo, endo-norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic dianhydride A mixture of the compounds (alicyclic tetracarboxylic dianhydride monomer: 99 mol% of the compound represented by the above general formulas (14) and (15) (the remaining component is norbornane-2-spiro-α -Trans-endo-endo isomers and cis-endo-endo isomers of cyclopentanone-α'-spiro-2 ''-norbornane-5,5 '', 6,6 ''-tetracarboxylic dianhydride And a molar ratio of the compound represented by the general formula (14) and the compound represented by the general formula (15) ([formula (14)]: [formula ( 15)]) is a mixture of 63:37) It was.

  In addition, the value measured by HPLC measurement was employ | adopted for identification of the isomer in a compound. For such HPLC measurement, a trade name “1200 Series” manufactured by Agilent Technologies Inc. is used as a measuring device, and a trade name “Eclipse XDB-C18 (5 μm, diameter 4.6 mm, length) manufactured by Agilent Technologies Inc. is used as a column. 150 mm) ”, a mixture of acetonitrile and distilled water (acetonitrile / distilled water = 70 ml / 30 ml) was used as the solvent, and the flow rate of the solvent was 1 ml / min. The detection wavelength of the diode array detector (DAD) was set to 210 nm, the temperature was set to 35 ° C., and 1 mg of the compound to be measured as a sample was added to 1.5 ml of the solvent. The total amount of trans-endo-endo isomer and cis-endo-endo isomer (content ratio: purity), and the molar ratio of trans-endo-endo isomer to cis-endo-endo isomer were determined by HPLC. It calculated | required by calculating using a calibration curve (standard sample: naphthalene) from the area ratio.

<Preparation process of polyamic acid solution>
First, a 30 ml three-necked flask was heated with a heat gun and sufficiently dried. Next, the atmosphere gas in the three-necked flask that was sufficiently dried was replaced with nitrogen, and the inside of the three-necked flask was changed to a nitrogen atmosphere. Next, 0.2045 g (0.90 mmol: manufactured by Nippon Pure Chemicals Co., Ltd .: 4,4′-DABAN) was added to the three-necked flask, and then N, N-dimethyl was added. By adding 2.7 g of acetamide and stirring, 4,4′-diaminobenzanilide (aromatic diamine compound: 4,4′-DABAN) was dissolved in the N, N-dimethylacetamide to obtain a solution. (Note that 4,4′-DABAN was partially dissolved).

  Next, 0.3459 g of the mixture (alicyclic tetracarboxylic dianhydride monomer) represented by the general formulas (14) and (15) is placed in a three-necked flask containing the solution under a nitrogen atmosphere. (0.90 mmol) was added, and the mixture was stirred at room temperature (25 ° C.) for 12 hours under a nitrogen atmosphere to form a polyamic acid to obtain a reaction solution (polyamic acid solution). Thus, polyamic acid was formed in the solvent (N, N-dimethylacetamide) to obtain a reaction liquid (polyamic acid solution).

  In addition, the intrinsic viscosity [η] of the polyamic acid formed in this manner was measured using an automatic viscosity measuring apparatus (trade name “VMC-252”) manufactured by Koiso Co., Ltd., with N, N-dimethylacetamide as a solvent, A measurement sample of 0.5 g / dL of polyamic acid was prepared and measured under a temperature condition of 30 ° C. That is, using a part of the reaction solution (polyamic acid solution (solvent: N, N-dimethylacetamide)), an N, N-dimethylacetamide solution having a polyamic acid concentration of 0.5 g / dL was prepared. When the intrinsic viscosity [η] of the polyamic acid was measured under the above conditions, the intrinsic viscosity [η] of the polyamic acid was 0.91 dL / g.

<Preparation process of first film made of polyimide>
Spin coat the reaction solution (polyamic acid solution) obtained as described above on a glass plate (length: 75 mm, width 50 mm, thickness 1.3 mm) so that the thickness of the heat-cured coating film is 13 μm. Then, a coating film was formed on the glass plate. Next, the glass plate on which the coating film was formed was placed on a hot plate at 60 ° C. and allowed to stand for 2 hours to evaporate the solvent. Thereafter, the glass plate on which the coating film (coating film after evaporation of the solvent) was formed was put into a 250 mm square inert oven in which nitrogen was flowing at a flow rate of 3 L / min. The film was allowed to stand for 0.5 hour under the temperature conditions of 0.5 ° C., then heated for 0.5 hours under the temperature condition of 135 ° C., and further heated for 1 hour under the temperature condition of 370 ° C. A first film consisting of was formed. Next, the glass plate on which the first film made of polyimide is formed is taken out from an inert oven, immersed in water at 90 ° C. for 10 minutes, and the first film made of polyimide is peeled off from the glass plate and collected. A first film made of polyimide (color: colorless and transparent, size: length 75 mm, width 50 mm, thickness 13 μm) was obtained.

<Preparation process of polyimide film (second film: stretched film)>
After fixing one side of the first film made of polyimide having a width of 50 mm, the weight is further applied to the other side of the side having a width of 50 mm (a portion on the side opposite to the fixed side). A 50 g weight was suspended and placed in an inert oven in which nitrogen was flowing at a flow rate of 3 L / min. Then, in an inert oven, under a nitrogen atmosphere in which the oxygen content is less than 20 ppm, heat to 400 ° C. (maximum temperature during heating) (heating rate at heating 5 ° C./min), After stretching the first film by the weight of the weight, the temperature condition inside the inert oven is returned to room temperature (25 ° C.), the film is allowed to cool naturally, and a polyimide film (second film: after stretching) Film). With respect to such a film, the length before and after stretching (the length of the first film and the second film (the length excluding the grip portion at the time of fixation)) at room temperature (25 ° C.) by the above-described method, respectively. As a result of measuring and calculating the draw ratio, the draw ratio was 1.0149 times.

In addition, IR spectrum of the compound which comprises the obtained polyimide film (2nd film: stretched film) was measured. The IR spectrum of the obtained compound is shown in FIG. As apparent from the results shown in FIG. 3, in the obtained compound, C═O stretching vibration of imide carbonyl was confirmed at 1697 cm ^−1, and it was confirmed that the obtained compound was polyimide.

  Furthermore, using the polyimide film thus obtained (second film: stretched film), the linear expansion coefficient of polyimide was measured as described above. As a result of such measurement, the linear expansion coefficient at 350 ° C. of the polyimide forming the film (average linear expansion coefficient between 349 and 351 ° C.) is 5.8 ppm / K, and the average linear expansion between 50 ° C. and 400 ° C. The coefficient was 7.5 ppm / K, and the average linear expansion coefficient from 50 ° C. to 200 ° C. was 8.3 ppm / K. The obtained results are shown in Table 1. Moreover, the graph which shows the relationship between the change of the length of the polyimide film (2nd film: film after extending | stretching) calculated | required at the time of the measurement of a linear expansion coefficient, and temperature is shown in FIG.

  Further, when the softening temperature and 5% weight reduction temperature of the polyimide forming the obtained film were measured by the above-mentioned methods, the softening temperature of the polyimide by the penetration method was 502 ° C., and the 5% weight reduction temperature was 482 ° C. Met. In addition, the obtained polyimide film was colorless and transparent, and was sufficiently high in transparency.

  Moreover, the glass transition temperature of the polyimide which forms the obtained film is measured using a differential scanning calorimeter (trade name “DSC7020” manufactured by SII Nano Technology Co., Ltd.) as a measuring device, and the scanning temperature is from 30 ° C. to 500 ° C. The glass transition temperature was not observed up to 500 ° C., although it was measured in a nitrogen atmosphere under the conditions of temperature rise rate: 10 ° C./min and temperature drop rate: 30 ° C./min. From these results, it can be seen that the glass transition temperature of the polyimide forming the obtained film is not below 500 ° C.

(Example 2)
In the process of preparing a polyimide film (second film: film after stretching), the heating temperature during stretching (maximum temperature during heating) was changed from 400 ° C. to 380 ° C. A polyimide film (second film: stretched film) was obtained by employing the same method. Table 1 shows the evaluation results of the characteristics of such a polyimide film. In addition, the obtained polyimide film was colorless and transparent, and was sufficiently high in transparency.

(Example 3)
In the process of preparing a polyimide film (second film: film after stretching), the heating temperature during stretching (maximum temperature during heating) was changed from 400 ° C. to 420 ° C., and the method employed in Example 1 A polyimide film (second film: stretched film) was obtained by employing the same method. Table 1 shows the evaluation results of the characteristics of such a polyimide film. In addition, the obtained polyimide film was colorless and transparent, and was sufficiently high in transparency.

Example 4
Example 1 except that in the preparation process of the polyimide film (second film: stretched film), the weight of the weight hanging from the side of the first film made of polyimide was changed from 50 g to 25 g. The polyimide film (2nd film: film after extending | stretching) was obtained by employ | adopting the method similar to the method employ | adopted by. Table 1 shows the evaluation results of the characteristics of such a polyimide film. In addition, the obtained polyimide film was colorless and transparent, and was sufficiently high in transparency.

(Example 5)
Example 1 except that the weight of the weight hanging from the side of the first film made of polyimide was changed from 50 g to 100 g in the preparation process of the polyimide film (second film: film after stretching). The polyimide film (2nd film: film after extending | stretching) was obtained by employ | adopting the method similar to the method employ | adopted by. Table 1 shows the evaluation results of the characteristics of such a polyimide film. In addition, the obtained polyimide film was colorless and transparent, and was sufficiently high in transparency.

(Example 6)
Example 1 except that the weight of the weight hanging on the side 50 mm wide of the first film made of polyimide was changed from 50 g to 200 g in the preparation process of the polyimide film (second film: film after stretching). The polyimide film (2nd film: film after extending | stretching) was obtained by employ | adopting the method similar to the method employ | adopted by. Table 1 shows the evaluation results of the characteristics of such a polyimide film. In addition, the obtained polyimide film was colorless and transparent, and was sufficiently high in transparency.

(Comparative Example 1)
A polyimide film for comparison was obtained by adopting the same method as that employed in Example 1 except that the step of preparing the polyimide film (second film: film after stretching) was not performed. That is, the first film made of polyimide (color: colorless and transparent, size: length 75 mm, width 50 mm, thickness 13 μm) obtained by the step of preparing the first film made of polyimide described in Example 1, A polyimide film (unstretched film) for comparison was used as it was.

  Table 1 shows the evaluation results of the characteristics of such a polyimide film. Moreover, the graph which shows the relationship between the change of the length of the polyimide film (2nd film: film after extending | stretching) calculated | required at the time of the measurement of a linear expansion coefficient, and temperature is shown in FIG. Furthermore, when the softening temperature and 5% weight reduction temperature of the polyimide forming the obtained film were measured by the above-described methods, the softening temperature of the polyimide by the penetration method was 501 ° C., and the 5% weight reduction temperature was 482 ° C. Met.

(Comparative Example 2)
In the process of preparing a polyimide film (second film: stretched film), a polyimide film for comparison was obtained by adopting the same method as that employed in Example 1 except that the weight was not hung. It was. That is, the first film made of polyimide obtained by the “preparing step of the first film made of polyimide” described in Example 1 (color: colorless and transparent, size: length 75 mm, width 50 mm, thickness 13 μm). Was subjected to heat treatment at 400 ° C. under no load to obtain a polyimide film (unstretched film) for comparison.

  Table 1 shows the evaluation results of the characteristics of such a polyimide film (unstretched film). In addition, the obtained polyimide film was colorless and transparent, and was sufficiently high in transparency.

(Comparative Example 3)
In the process of preparing a polyimide film (second film: stretched film), after heating to 400 ° C., the weight of the weight hanging on the side of 50 mm across the first film made of polyimide is maintained at 400 ° C. When the thickness was increased from 50 g (the load was increased) and the breaking point was confirmed, it was confirmed that the film was broken when the weight of the weight was 700 g (at a load of 700 g). In addition, when the draw ratio was calculated | required from the length of the fractured film obtained when the weight of the weight was 700 g, it was found that the draw ratio was 1.0680 times. The obtained results are shown in Table 1.

(Comparative Example 4)
In the process of preparing a polyimide film (second film: film after stretching), the heating temperature during stretching (maximum temperature during heating) was changed from 400 ° C. to 360 ° C., and the method employed in Example 1 A polyimide film (second film: stretched film) was obtained by employing the same method. Table 1 shows the evaluation results of the characteristics of such a polyimide film (unstretched film). In addition, the obtained polyimide film was colorless and transparent, and was sufficiently high in transparency.

  As is clear from the results shown in Table 1, when the polyimide film was produced using the method for producing a polyimide film of the present invention (Examples 1 to 6), all the obtained polyimide films were 350 ° C. The linear expansion coefficient was 10 ppm / ° C. or less, and the average linear expansion coefficient in the temperature range of 50 ° C. to 400 ° C. was 15 ppm / ° C. or less. On the other hand, when the film was not stretched as in Comparative Examples 1 and 2, the linear expansion coefficient in the temperature range of 50 to 200 ° C. of the obtained film (unstretched film) was a sufficiently low value. However, the linear expansion coefficients at 350 ° C. were 89.8 ppm / ° C. (Comparative Example 1) and 19.0 ppm / ° C. (Comparative Example 2), respectively. As compared with 6), it was found that the increase in the linear expansion coefficient at high temperature could not be sufficiently suppressed. In addition, even when the stretching process was performed, when the film was stretched with a load of 700 g (Comparative Example 3), the film was broken and a stretched film could not be formed. In the case where the film was stretched at an atmospheric temperature of 360 ° C. (Comparative Example 4), even when the film was stretched with the same load as in Examples 1 to 3 and the stretch ratio was 1.0079, 350 The linear expansion coefficient at 1 ° C is 11.4 ppm / ° C. Furthermore, the average linear expansion coefficient in the temperature range of 50 ° C to 400 ° C is 23.1 ppm / ° C, and the linear expansion coefficient at 350 ° C or higher is high. It has been found that an increase in the expansion coefficient cannot always be sufficiently suppressed. From the results of Comparative Examples 2 and 4, when the first film was not stretched even when heated to 400 ° C. (Comparative Example 2), the increase in the linear expansion coefficient at high temperature was not necessarily sufficiently suppressed. In addition, even when the first film is stretched, if the atmospheric temperature during stretching is 360 ° C. (Comparative Example 4), the increase in the linear expansion coefficient at high temperature is not always sufficient. It turns out that it cannot be suppressed. The present inventors speculate that such a result is caused by the change in the orientation state of the molecular chain of the polymer depending on the stretching temperature and the stretching load. In addition, if the measurement result of the 5% weight reduction | decrease temperature and softening temperature of the polyimide film obtained in Example 1 and Comparative Example 1 is considered, all the polyimide films obtained in each Example and each Comparative Example are sufficient. It can be seen that it has a high heat resistance. In addition, from the results shown in Table 1, when considering the relationship between the increase in load and temperature and the value of the draw ratio, there are cases where the load is increased at the same atmospheric temperature and the draw ratio is decreased. The inventors speculate that this is caused by shrinkage of the film when it is cooled to room temperature (25 ° C.) after stretching. That is, because the orientation state inside the film differs depending on the load and temperature difference employed in the stretching process, it does not necessarily shrink uniformly during cooling, and after stretching, the components in the film Since shrinkage occurs in accordance with the orientation state, the stretch ratio may be lower than the stretched one with a higher load than when stretched with a lower load. The present inventors speculate that it was obtained. In addition, from the above-mentioned results, when the step of stretching was carried out at an atmospheric temperature of 370 to 450 ° C. so that the stretching ratio was 1.0001 to 1.050, the linear expansion coefficient at a high temperature was sufficient. It has been found that it is possible to make it low.

  Further, as is clear from the results shown in FIGS. 4 and 5, in the polyimide film obtained in Comparative Example 1, the film length increases in the temperature range from around 350 ° C. to about 400 ° C. In the polyimide film obtained in Example 1 (polyimide film of the present invention), the ratio to be increased rapidly, in the temperature range from around 350 ° C. to about 400 ° C. However, there was no abrupt change in the rate of film length increase. From these results, in the polyimide film obtained in Example 1 (polyimide film of the present invention), an increase in the linear expansion coefficient at high temperatures can be sufficiently suppressed, and the linear expansion coefficient at high temperatures is sufficient. It turned out to be low.

  As described above, according to the present invention, it is possible to provide a polyimide film excellent in light transmittance and heat resistance, and having a sufficiently low linear expansion coefficient at high temperature, and a method for producing the same. Furthermore, according to this invention, it becomes possible to provide the flexible wiring board which consists of the said polyimide film, the board | substrate for transparent electrodes, and the board | substrate for liquid crystal aligning film lamination | stacking.

  Such a polyimide film of the present invention is excellent in light transmittance and heat resistance and has a sufficiently low linear expansion coefficient at high temperatures. For example, a flexible wiring board, a transparent electrode substrate (for example, a touch panel or In addition to films used for applications such as a substrate film for laminating transparent electrodes of solar cells and a substrate film for laminating transparent electrodes of display devices (organic EL display devices, liquid crystal display devices, etc.), FPC (flexible Printed circuit board), optical waveguide, image sensor, LED reflector, LED reflector, LED illumination cover, skeleton FPC, cover lay film, chip on film, high ductility composite substrate, liquid crystal alignment film, polyimide coating material (DRAM) , Flash memory, buffer coating materials such as next generation LSI), semiconductor Resist, lithium ion battery, film used for various electric materials, organic EL display substrate, organic EL lighting substrate, water vapor barrier film substrate, air barrier film substrate, organic memory substrate, organic transistor substrate, organic It is particularly useful as a semiconductor substrate, a belt for copying machines, a front film for flexible displays, a back film for flexible displays, a hard coat film for flexible displays, and the like.

Claims (12)

The following general formulas (1) and (2):
[In the formulas (1) and (2), R ¹ , R ² and R ³ each independently represent one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluorine atom. , R ⁴ represents an aryl group having 6 to 40 carbon atoms, and n represents an integer of 0 to 12. ]
Containing at least one of the repeating units represented by:
The total amount of the repeating units represented by the general formulas (1) and (2) is 90 mol% or more based on all repeating units,
The linear expansion coefficient at 350 ° C. is 10 ppm / ° C. or less, and
The average linear expansion coefficient determined by measuring the change in length in the temperature range of 50 ° C. to 400 ° C. under a temperature increase rate of 5 ° C./min under a nitrogen atmosphere is 15 ppm / ° C. or less.
A polyimide film characterized by being a film made of polyimide.   2. The polyimide film according to claim 1, wherein the polyimide has a linear expansion coefficient at 350 ° C. of 1 to 10 ppm / ° C. 3. R ⁴ in the general formulas (1) and (2) is represented by the following general formulas (3) to (6):
[In the formula (5), R ⁵ represents one selected from the group consisting of a hydrogen atom, a fluorine atom, a methyl group, an ethyl group and a trifluoromethyl group, and in the formula (6), Q is a formula: _{-O -, - S -, -} CO -, - CONH -, - C 6 H 4 -, - COO -, - SO 2 -, - C (CF 3) 2 -, - C (CH 3) 2 -, _{-CH 2 -, - O-C} 6 H 4 -C (CH 3) 2 -C 6 H 4 -O -, - O-C 6 H 4 -SO 2 -C 6 H 4 -O -, - C ( _{CH 3) 2 -C 6 H 4} -C (CH 3) 2 -, - from _{O-C 6 H 4 -C 6} H 4 -O- and _{-O-C 6} group represented by H 4 -O- 1 type selected from the group consisting of ]
The polyimide film according to claim 1, wherein the polyimide film is one type of a group represented by the formula: The following general formula (7):
Wherein ^{(7), R 1, R} 2, R 3 are each independently a hydrogen atom, represents one selected from the group consisting of alkyl groups and fluorine atom having 1 to 10 carbon atoms, ^{R 4} is An aryl group having 6 to 40 carbon atoms is shown, and n is an integer of 0 to 12. ]
An alicyclic tetracarboxylic dianhydride (A) represented by the following general formula (8):
Wherein ^{(8), R 1, R} 2, R 3, n are as defined ^{R 1, R 2, R 3} , n in the general formula (7). ]
At least one of the alicyclic tetracarboxylic dianhydrides (B) represented by the formula (1) and the total amount of the alicyclic tetracarboxylic dianhydrides (A) and (B) is 90 mol. % Alicyclic tetracarboxylic dianhydride monomer,
The following general formula (9):
[In the formula (9), R ⁴ represents an aryl group having 6 to 40 carbon atoms. ]
The following general formulas (10) and (11) obtained by reacting with an aromatic diamine represented by:
In formula (10) and ^{(11), R 1, R} 2, R 3, n has the same meaning as ^{R 1, R 2, R 3} , n in the general formula (7), ^{R 4} is the general the same meaning as ^{R 4} in the formula (9). ]
Using a polyamic acid solution containing at least one type of repeating unit represented by formula (10) and a polyamic acid containing a polyamic acid having a total amount of repeating units represented by the general formulas (10) and (11) of 90 mol% or more, General formula (1) and (2):
[In the formulas (1) and (2), R ¹ , R ² and R ³ each independently represent one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluorine atom. , R ⁴ represents an aryl group having 6 to 40 carbon atoms, and n represents an integer of 0 to 12. ]
Polyimide containing at least one of the repeating units represented by the formula (1) and the total amount of the repeating units represented by the general formulas (1) and (2) being 90 mol% or more based on all repeating units. Obtaining a first film comprising:
The first film is stretched in an inert gas atmosphere at an atmospheric temperature of 370 to 450 ° C. so that the stretching ratio is 1.0001 to 1.050, thereby forming a second film. And obtaining a polyimide film,
The manufacturing method of the polyimide film characterized by including.   5. The method for producing a polyimide film according to claim 4, wherein when the first film is stretched, the first film is stretched so that the stretching ratio is 1.0005 to 1.030 times.   The polyimide film has a linear expansion coefficient at 350 ° C. of 10 ppm / ° C. or less, and the change in length is measured in a temperature range of 50 ° C. to 400 ° C. under a temperature increase rate of 5 ° C./min in a nitrogen atmosphere. 6. The method for producing a polyimide film according to claim 4, wherein the polyimide film has an average linear expansion coefficient of 15 ppm / ° C. or less.   A flexible wiring board comprising the polyimide film according to any one of claims 1 to 3.   A transparent electrode substrate comprising the polyimide film according to claim 1.   The transparent electrode substrate according to claim 8, wherein the transparent electrode substrate is used for laminating a transparent electrode of any one of a display device and a solar cell.   It consists of a polyimide film as described in any one of Claims 1-3, The board | substrate for liquid crystal aligning film lamination | stacking characterized by the above-mentioned.   It consists of a polyimide film as described in any one of Claims 1-3, The board | substrate for organic EL displays characterized by the above-mentioned.   It consists of a polyimide film as described in any one of Claims 1-3, The board | substrate for organic EL lighting characterized by the above-mentioned.