JPS61241359A - Polyimide precursor solution - Google Patents

Abstract

PURPOSE:A polyimide precursor solution, obtained by using a specific diamino compound and aromatic tetracarboxylic acid dianhydride as starting materials, and dissolving specific components in a specific proportion in a general-purpose solvent and having good handleability without problems in safety and hygiene. CONSTITUTION:A polyimide precursor solution, obtained by reacting a diamino compound expressed by formula I [X is C(CH3)2, etc.] woith a specific aromatic tetracarboxylic acid dianhydride (derivative) in a polyhydric alcohol expressed by formula II (m is >=4), and containing 80-20mol% total of (A) a component consisting of repeating units expressed by formula III and/or formula IV (Ar1 is 2,3,3',4'-biphenytetracarboxylic acid residue; Ar2 is 3,3',4,4'- benzophenonetetracarboxylic acid residue) and (B) a component consisting of repeating units expressed by formula V and/or formula VI (Ar3 is 3,3',4,4'- biphenyltetracarboxylic acid residue; Ar4 is pyromellitic acid residue) and (C) 20-80mol% component consisting of repeating units expressed by formula VII, etc. The ratio of the components (A) to (B) is 100-80mol% component (A) and 0-20mol% component (B).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a polyimide precursor solution using a polyhydric alcohol derivative, which is a general-purpose solvent, as a solvent for the polyimide precursor.

[Conventional technology]

Generally, aromatic polyimides with high heat resistance do not require organic solvents, and therefore cannot be processed into molded products such as films as they are. Therefore, N is usually used in the form of polyamic acid, which is a precursor of polyimide.
-Methyl-2-pyrrolidone, N,N'-dimethylacetamide, N.

No-dimethylformamide, dimethyl sulfoxide,
Hexamethylphosphoramide dissolved in an organic polar solvent,
It is cast onto a glass plate or the like, and heat-treated at high temperatures to cause dehydration and ring closure, thereby producing a polyimide film or the like. However, since all of the organic polar solvents described above are skin-absorbable and highly toxic, handling them is complicated, such as having to wear solvent-resistant gloves, and there are difficulties in handling them. In addition, these organic polar solvents have strong dissolving power, so when a solution of the above-mentioned polyamic acid in an organic polar solvent is applied to a material to be coated and cured by heating to form a polyimide film on the surface of the material to be coated, If an organic material is used as a coating material, the material will be attacked by the above-mentioned organic polar solvent, so inorganic materials such as metals and metal oxides must be used as the coating material, which limits the scope of application of polyimide. Narrowed by organic polar solvent.

Since organic polar solvents have the above-mentioned drawbacks, polyimide precursors that dissolve in other solvents have been researched.
Polyimide precursors that are soluble in phenolic solvents such as phenol and cresol have been developed. Polyimide precursor solutions using such phenolic solvents have health and safety problems because the phenolic solvent has a strong odor (for example, cresol odor) and may cause burns if it comes in contact with the skin.

[Problem that the invention seeks to solve]

As mentioned above, in the past, polyimide precursors that are soluble in general-purpose solvents without toxicity or odor have not been developed, resulting in various problems as described above. Therefore, the purpose of the present invention is to provide a polyimide precursor solution that is easy to handle, does not cause health and safety problems, and has a wide range of applications by developing a polyimide precursor that can be dissolved in a general-purpose solvent. It is something to do.

[Means for solving problems]

In order to achieve the above object, the polyimide precursor of the present invention contains 100 to 80 mol% of the following components A and B in total, and 0 to 20 mol% of the following C component, and The mutual ratio of component A and component B is less than 80 mol% of component A and 20 mol% or more of component B, when the total amount of components A and B is 100 mol%. This is a polyimide precursor solution consisting of a polyimide precursor whose proportion is less than 80 mol % and a solvent thereof, and the solvent has the following component D as a main component.

(A) Repeating unit represented by general formula (1) and general formula (
At least one of the repeating units represented by 2).

(B) Repeating unit represented by general formula (3) and general formula (
4) At least one of the repeating units represented by.

(C) Repeating unit represented by general formula (5), general formula (6)
At least one of a repeating unit represented by formula (7), and a repeating unit represented by general formula (8).

(D) A polyhydric alcohol derivative represented by general formula (9).

H3C (0-CIICI 艙OCH3・・・・・・・（
9) [In formula (9), m is an integer of 3 or more. ]
The present inventors have conducted a series of studies to develop polyimide precursors that are soluble in general-purpose solvents, and have found that the raw materials used in the synthesis of polyimide precursors have a large effect on the solubility of polyimide precursors. In particular, we found that it is present in diamino compounds, and using a specific aromatic tetranuclear diamine,
When this is combined with two or more specific aromatic tetracarboxylic dianhydrides or derivatives thereof, excellent solubility can be achieved in the polyhydric alcohol derivative represented by general formula (9), which is a general-purpose solvent. The present invention was achieved by discovering that a polyimide precursor having the following properties can be obtained.

Since the polyimide precursor solution of this invention uses a polyhydric alcohol derivative, which is a general-purpose solvent, as a solvent for the polyimide precursor, there is no need to wear solvent-resistant gloves when handling it, and it does not adhere to the skin. It does not cause burns, and the polyhydric alcohol derivative does not have a strong dissolving power in the organic polar solvent, so it can be applied to organic materials as well. Moreover, the polyimide precursor solution of the present invention can form a polyimide having excellent properties equivalent to those of conventional polyimides. In other words, in order to improve the solubility of wholly aromatic polyimide precursors, bulky substituents are generally introduced into the polymer to reduce its crystallinity, or ortho- or meta- It is conceivable to use substituted diamines to make the molecular chains of the polymer zigzag-shaped to reduce its crystallinity. However, when the solubility of the polyimide precursor is improved in this way, the resulting polyimide deteriorates in properties such as toughness.

However, the present invention does not rely on the conventional method of reducing the crystallinity of the polymer as described above, but instead selects a specific diamino compound as a starting material for a polyimide precursor, and combines this with a specific aromatic tetracarboxylic compound. The effect of combining two or more types of acid dianhydrides or their derivatives, and the effect of the selected combination, and the effect of copolymerizing several types of acid component raw materials and disrupting the symmetry of the polymer and the regularity of repeating units. This method improves the solubility of the polyimide precursor and manufactures a polyimide precursor solution by selecting and using a general-purpose solvent that is optimal for dissolving the generated precursor.The resulting polyimide has good properties and has good toughness, etc. In terms of properties, it has almost the same properties as conventional polyimide.

The polyimide precursor used in this invention usually uses a diamino compound represented by the following general formula (10), and in some cases, a part of it is added to the following general formula (11)% formula% (10
) [In the formula, X is as shown in the general formula (1) above. ], and together with this, an aromatic tetracarboxylic dianhydride or a derivative thereof represented by the following general formula (12), an aromatic tetracarboxylic acid dianhydride represented by the general formula (13) Acid dianhydrides or derivatives thereof, aromatic tetracarboxylic dianhydrides represented by general formula (14) or derivatives thereof, aromatic tetracarboxylic dianhydrides represented by general formula (14) or derivatives thereof It can be obtained by reacting with one or more of them.

(Ar is as in the above 7-F general formula (1).)
(Ar is as in the general formula (2) above.) (Ar
:+ is as shown in the general formula (3) above. ] (Margin) (Ar is as in the general formula (4) above.) Typical examples of the diamino compound represented by the above general formula (10) are 2.2-bis(4-(4- aminophenoxy)
Phenyl]propane, 2.2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 4.
Examples include 4'-di(4-aminophenoxy)diphenylsulfone. Preferred is 2,2-bis(4-(4-
aminophenoxy)phenyl]propane. The aromatic tetranuclear diamines exemplified above may be used alone or in combination.

Further, typical examples of the diaminosiloxane represented by the general formula (11) are as follows.

cow Cl.

CH3CO.

C6H! l ChHs CH3 (Hh CHz OCH3C)+3 The above-mentioned diaminosiloxane is used when it is necessary to particularly impart adhesion to silicon-containing materials such as silicon wafers and glass to polyimide. Excessive use impairs polyimide's heat resistance and moisture resistance. Therefore, the amount of diaminosiloxane represented by the above general formula (11) is 1 to 1 in the total diamino compound.
It is necessary to suppress it within the range of 20 mol%. The preferred range is 1-4 mol%, and the most preferred range is 2-3.
It is 5 mol%. When polyimide is used in fields where adhesion to silicon-containing materials is not required, such as in polyimide films, it is not necessary to use the diaminosiloxane represented by the above general formula (11).

The aromatic tetracarboxylic dianhydride represented by the above general formula (12) is 2.3.3',4'-biphenyltetracarboxylic dianhydride, and the aromatic tetracarboxylic dianhydride represented by the general formula (13) Group tetracarboxylic dianhydride is 3.3', 4
．． 4'-benzophenonetetracarboxylic dianhydride. These may be used alone or in combination, and derivatives such as esters and acid chlorides thereof may also be used.

However, particularly preferred are dianhydrides. The use of dianhydrides makes it possible to obtain polyimide precursors with particularly excellent properties.

Further, the aromatic tetracarboxylic dianhydride represented by the general formula (14) is 3. 3', 4. It is 4'-biphenyltetracarboxylic dianhydride, and has the general formula (15
The aromatic tetracarboxylic dianhydride represented by ) is pyromellitic dianhydride. These may be used alone or in combination, and derivatives such as esters and acid chlorides thereof may also be used. However, particularly preferred are dianhydrides. The aromatic tetracarboxylic dianhydride represented by the general formula (12) or (13) or its derivative becomes a constituent component of the repeating unit represented by the general formula (1) or (2), and the general formula (14) ), (15) The aromatic tetracarboxylic dianhydride or its derivative is a constituent of the repeating unit represented by the general formulas (3) and (4). If the ratio of the repeating units represented by the general formulas (1) and (2) to the repeating units represented by the general formulas (3) and (4) is out of the appropriate range, the solvent in the polyimide precursor Since the characteristics for ), the repeating units represented by general formulas (3) and (4) (component B)
is more than 20 mol% and less than 80 mol% (this is defined as 1 mol%), and the repeating units (component A) represented by general formula (1) and general formula (2) are 1001 mol%. of less than 80 mol% and 20 mol% or more.

As mentioned above, the aromatic tetracarboxylic dianhydride represented by the above general formulas (12) and (13) or its derivatives is converted into the aromatic tetracarboxylic dianhydride represented by the general formulas (14) and (15). Used with anhydrides or their derivatives,
When these are reacted with a diamino compound represented by general formula (10) or a diamino compound represented by general formula (11) in the same reaction vessel, general formulas (1) and (2) are obtained.

In all of the repeating units represented by (3) and (4), the diamino compound residue is derived from general formulas (10) and (11) and becomes common. However, the diamino compounds are not limited to those represented by the above general formulas (10) and (11), and some of them may be replaced with the above general formulas (10) and (11).
) may be used. However, in this case, care must be taken so that the solubility of the polyimide precursor according to the present invention is not impaired by the use of the other diamino compounds mentioned above. Therefore, when using the above-mentioned other diamino compounds, the amount used must be limited to 10 mol% of the total diamino compounds. In this case, the above other diamino compound and the above general formula (1
The reaction products with aromatic tetracarboxylic dianhydrides represented by 2) to (15) are the above-mentioned (A), (B),
It becomes the fourth component other than the component (C).

The polymerization reaction between the aromatic tetracarboxylic dianhydride or its derivative and the diamino compound may be carried out according to a conventionally known method, and usually, in the polyhydric alcohol derivative represented by the general formula (9), The aromatic tetracarboxylic dianhydride or its derivative and the diamino compound are charged in equal moles or approximately equal moles, preferably under a nitrogen gas stream, and the temperature is limited to 80°C or less, preferably 60°C or less, taking into account the heat generated by polymerization. The reaction is continued until a high degree of polymerization is obtained. This degree of polymerization can be easily detected by examining the intrinsic viscosity η of the reactant, and it is preferable that the intrinsic viscosity falls within the range of 0.3 to 3.0.

The above intrinsic viscosity [η] is determined by reprecipitating the polyimide precursor with water from the obtained polyimide precursor solution, drying it under reduced pressure at a temperature of 40°C or less, and drying the obtained dry product with N-methyl- Dissolved in 2-pyrrolidone, measurement temperature 30±0.0
At 1°C (thermal bath), the following formula: % formula %) t: Falling time toH of the polymer solution measured with an Ubbelohde viscometer C: Falling time of the solvent measured in the same manner as above C: Concentration of the polyimide precursor ( 0.5% by weight).

The polyhydric alcohol derivative represented by the above general formula (7) is
In the above formula (9), m is an integer of 3 or more, and m is usually up to 6, and m is preferably 3.4 or 5.6. Representative examples include triethylene glycol dimethyl ether,
Examples include glycol dialkyl ethers such as tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, and hexaethylene glycol dimethyl ether, which can be used alone or in combination. In particular, in the polyimide precursor according to the present invention, there is a tendency that as the proportion of component B increases, it will not dissolve smoothly unless a polyhydric alcohol derivative having a high value of m is used. Therefore, it is important to select a solvent based on this.

These polyhydric alcohol derivatives are chemically inert compared to organic polar solvents, such as N,N''-dimethylformamide, and are also low volatile and difficult to attract, and have excellent handling and workability. be.

In this way, the polyimide precursor solution of the present invention is obtained. This polyimide precursor solution is usually 15 to 3
Used at a concentration of 0% by weight. It goes without saying that the polyhydric alcohol derivative represented by the above general formula (7) can be used as it is as a diluting solvent for the polyimide precursor solution in this case. In addition, conventionally used organic polar solvents or phenolic solvents can also be used within a range that does not impair handling properties (usually 50% by weight or less of the total solvent composition).

In this case, since the amount of organic polar solvent or phenolic solvent used is less than half of the conventional amount, the harmful effects thereof are also significantly reduced. Furthermore, hydrocarbon solvents such as benzene and xylene, which do not have the ability to dissolve the polyimide precursor, ketone solvents, alcohol solvents, ester solvents, ether solvents, and glycol monoether solvents, and m= Various general-purpose solvents such as glycol dialkyl ether solvents represented by =l and 2 can also be used as diluting solvents within a range that does not precipitate the polyimide precursor.

In addition, in this invention, the polyimide precursor includes one partially imidized by dehydration and ring closure,
It refers to something that has not yet gone through the imidization process. In addition, the polyimide precursor solution of the present invention uses an organic polar solvent as a polymerization solvent, and after synthesizing the polyimide precursor, by solvent substitution, the synthetic polyimide is added to the polyhydric alcohol derivative represented by the general formula (9). It may also be manufactured by dissolving a precursor.

In addition, the feed concentration at the time of polyimide precursor synthesis is generally suitable to be in the range of 5 to 50% by weight, but this can be arbitrarily selected depending on the economical point of view or the purpose of use. In addition, since the polymer solution after the reaction has a high degree of polymerization, the viscosity of the solution may be considerably higher than the intended viscosity in some cases, but even in this case, it is usually 40 to 8
The viscosity can be lowered to a desired level by heating it to 0°C and passing through an aging process.

The polyimide precursor solution of the present invention uses the above-mentioned general-purpose solvent, so it has excellent handling properties, and after applying it to an adherend, it can be heated at high temperature for dehydration and ring closure. It can be converted into polyimide with excellent properties such as heat resistance, toughness, and so on. It goes without saying that it can also be used to produce polyimide films. In these cases, the imidization method is not limited to heating imidization as described above; for example, the polyimide precursor solution is cast on a glass plate and dried to form a film, and the resulting film is mixed with pyridine. Chemical imidization can also be carried out, such as by immersing the material in a benzene solution of acetic anhydride to perform a solvent removal and imidization reaction to form a polyimide film. In particular, when the polyimide precursor solution of the present invention is used as a protective film, a passivation film, an α-ray shielding film, etc. on the surface of a semiconductor element, adhesion to a silicon-containing material as an adherend is required. In such cases,
As already mentioned, the diaminosiloxane represented by the general formula (11) is an aromatic 4 represented by the general formula (10).
It is used together with a nuclear diamine, but instead of reacting these with an aromatic tetracarboxylic dianhydride or its derivative in the same reaction vessel to synthesize a polyimide precursor consisting of a copolymer, the general method described above is used. Formula (1
Diaminosiloxane represented by 1) and the general formula (10
) are reacted with the aromatic tetranuclear diamine represented by the following in separate reaction vessels to synthesize two types of polyimide precursors, and by mixing these after synthesis, the desired polyimide precursor solution can be obtained. It may also be manufactured. However, rather than doing this, it is preferable to make the generated polyimide precursor into a copolymer as described above, and this allows for the formation of polyimide with stable quality without variations in adhesion and moisture resistance properties. This makes it possible to produce a polyimide precursor solution that can be used in various ways.

Further, the polyimide precursor solution of the present invention is very useful as a passivation film on the surface of a semiconductor element, etc.
It is often used when assembling semiconductor devices, but if ionic impurities are contained in the passivation film etc., they will have an adverse effect on the electrical characteristics, so it is necessary to remove the ionic impurities. As a method for this removal, each monomer component and the solvent used may be purified by known purification methods such as recrystallization and distillation, which allows almost complete removal of the ionic impurities.

As a guideline for the degree of purification, both Na ions and Cl ions are 5 ppn+ or less, preferably lpp theory or less.

〔Effect of the invention〕

As described above, since the polyimide precursor solution of the present invention uses a polyhydric alcohol derivative, which is a general-purpose solvent, it does not have the toxicity and skin absorption properties of conventionally used organic polar solvents. Therefore, it is not necessary to wear solvent-resistant gloves or the like when handling it, and it is easy to handle. Additionally, there is no odor or risk of burns like with phenolic solvents, so there are no health and safety issues.
It can be suitably used for various conventionally known applications. Furthermore, since the above-mentioned polyhydric alcohol derivatives do not have strong dissolving power like organic polar solvents, even if the polyimide precursor solution of the present invention is applied to an adherend made of an organic material such as polyester, There is no risk of melting the material to be adhered, and it can be applied to organic material adherends, which was previously impossible, and the range of application of polyimide can be greatly expanded. Moreover, this invention prevents the introduction of bulky substituents into the molecular structure of the polyimide precursor, or the use of ortho- or meta-substituted diamines as starting materials, which would reduce the crystallinity of the polymer. First, a specific diamino compound is selected as a starting material for a polyimide precursor, and this is combined with two or more specific aromatic tetracarboxylic dianhydrides or derivatives thereof. In order to improve the solubility of the polyimide precursor and create a solution by copolymerizing it with the acid component raw materials of good and therefore
It becomes possible to obtain a polyimide that has properties equivalent to conventional polyimides in terms of properties such as heat resistance and toughness. Since the polyimide precursor solution of the present invention has such excellent characteristics, it can be used in a wide range of applications and can exhibit excellent effects. For example, passivation films on the surface of semiconductor elements, protective films, diodes, cyclers,
Junction protective film for P-N junction of transistors, alpha ray shielding film for VLSI, glabella insulating film, liquid crystal alignment film for liquid crystal cells consisting of organic film substrates such as glass substrates or polyester substrates containing transparent electrodes, laminates, It can be suitably used for adhesives for sandwich structures of various substrates, various insulating films, etc. Further, the polyimide precursor solution of the present invention is useful not only for the above-mentioned uses but also as a binder for pastes in which various fillers such as inorganic and organic fillers are dispersed. For example, it can be used as a binder for heat-resistant conductive pastes containing conductive fillers such as silver powder, gold powder, palladium powder, etc. for chip bonding, electrodes of electronic parts, etc. In addition, the uranium and thorium contents are s pp
It can also be used as a screen printing paste for preventing soft errors by dispersing organic or inorganic fillers of B or less, and exhibits excellent effects in these applications.

Next, examples will be described together with comparative examples.

In addition, in the table below, a-BPDA is 2°3.3'
, 4”-biphenyltetracarboxylic dianhydride, 5
-BPDA is 3. 3', 4. 4'-biphenyltetracarboxylic dianhydride, BTDA is 3.3'
, 4.4'-benzophenonetetracarboxylic acid, P
MDA indicates pyromellitic dianhydride. In addition, in the Examples and Comparative Examples below, the viscosity of the solution is the value measured at 25°C using an EMD type rotational viscometer manufactured by Tokyo Keiki Co., Ltd., and the tensile strength 1 volume resistivity of the film is
This is a value measured according to SK6760 and JISK648. Adhesion was measured by forming a film on a silicon wafer (mirror silicon), conducting a test in accordance with JIS 00202, and examining (number of peels)/(total number).

[Examples 1 to 8, Comparative Examples 1 to 5] Using an aromatic tetranuclear diamine as a diamino compound, a solution of a polyimide precursor having no siloxane bond in its molecular structure was produced as follows.

That is, into a 500 ml flask equipped with a stirrer, a cooling tube, a thermometer, and a nitrogen purging device, the organic solvent shown in Table 1 purified by distillation was added in the amount shown in the table, and nitrogen gas was introduced. Next, the diamino compounds shown in Table 1 above were added in the amounts shown in the table and stirred, and then the acid dianhydrides shown in Table 1 were gradually added little by little over 5 minutes.

As a result, the viscosity of the reaction system gradually increased and the temperature rose to 38°C. Then, as a result of maintaining the temperature at 30°C and continuing stirring for 6 hours, the reaction system had a viscosity shown in Table 1, and
The desired polyimide precursor solution was obtained.

Next, the obtained polyimide precursor solution was applied onto a glass plate and heated at 150'C for 1 hour, at 200°C for 1 hour, and then at 250'C for 6 hours in a dryer to harden it and form a transparent polyimide film. Next, the obtained polyimide film was peeled off from the glass plate, and the tensile strength and volume resistivity were measured.The results are also shown in Table 1.

In order to make it easier to compare Examples 1 to 8 and Comparative Example 1, the polyimide films obtained using the polyimide precursor solutions of Examples 1 to 8 and the polyimide films of Comparative Example 1 obtained using an organic polar solvent were compared. It can be seen that the properties of the films are similar, and that the polyimide obtained from the polyimide precursor solution of the present invention has the same excellent properties as the conventional ones. Furthermore, in Comparative Examples 2 and 3, the resulting polyimide precursor solution became opaque due to polymer precipitation, and therefore could not be formed into a polyimide film.

(Left below) [Examples 9 and 10, Comparative Example 6] Using diaminosiloxane as well as aromatic tetranuclear diamine as the diamino compound, a solution of a polyimide precursor having a siloxane bond in its molecular structure was prepared as follows. Manufactured by

That is, the organic solvents, acid dianhydrides, and diamino compounds shown in Table 1 were replaced with the raw materials shown in Table 2, and the above Examples 1 to 8. A solution of a polyimide precursor having a siloxane bond in its molecular structure was produced in the same manner as in Comparative Examples 1 to 5. Then, the obtained solution was applied onto a glass plate in the same manner as above and cured by heating to form a polyimide film. In this case, the polyimide film obtained in Example 9 had good adhesion, but the polyimide film obtained in Example 10 had less adhesion than that in Example 9 because the amount of diaminosiloxane used was small. was not rich. On the other hand, although the polyimide film obtained in Comparative Example 6 had good adhesion to the glass plate, its thermal decomposition temperature (measured in air) was 320°C, which was lower than that of the polyimide film obtained in Example 9 at 415°C. It can be seen that the heat resistance is considerably inferior in comparison, and there is a problem in practical use.

(Margin below) Procedural amendment (voluntary) May 13, 1986

Claims (1)

[Claims] (1) The following A component and B component are 100 to 80 in total
Contains 0 to 20 mol% of the following C components.
When the total amount of A component and B component is 100 mol%, B is less than 80 mol% and 20 mol% or more of A component is contained.
A polyimide precursor solution consisting of a polyimide precursor whose components are selected at a ratio of more than 20 mol% and less than 80 mol%, and a solvent thereof, wherein the solvent has the following component D as a main component. A certain polyimide precursor solution. (A) Repeating unit represented by general formula (1) and general formula (
At least one of the repeating units represented by 2). ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(2) [In the above formulas (1) and (2), Ar_1 is 2, 3,
3',4'-biphenyltetracarboxylic acid residue, Ar_
2 is a 3,3',4,4'-benzophenonetetracarboxylic acid residue, X is C(CH_3)_2, C(CF_3)_
2 or SO_2. (B) Repeating unit represented by general formula (3) and general formula (
4) At least one of the repeating units represented by. ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(3) ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(4) In the above formulas (3) and (4), Ar_3 is 3, 3',
4,4'-biphenyltetracarboxylic acid residue, Ar_4
is a pyromellitic acid residue, and X is the same as in formulas (1) and (2) above. (C) Repeating unit represented by general formula (5), general formula (6)
At least one of a repeating unit represented by formula (7), and a repeating unit represented by general formula (8). ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(5) ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(6) ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(7) ▲Mathematical formulas , chemical formulas, tables, etc.▼……(8) [In the above formulas (5), (6), (7), and (8), A
r_1, Ar_2, Ar_3 and Ar_4 are formula (1)
, (2), (3), and (4), R is a divalent organic group, R' is a monovalent organic group, and n is an integer of 1 or more. ] (D) A polyhydric alcohol derivative represented by general formula (9). ▲There are mathematical formulas, chemical formulas, tables, etc.▼……(9) [In formula (9), m is an integer of 3 or more. ]