JPH0532894A - Solution composition of transparent aromatic polyimide - Google Patents

Abstract

PURPOSE:To obtain a soln. of an arom. polyimide excellent in solubility in org. polar solvents and transmission of visible light therethrough by polymn. and imidation of a specific tetracarboxylic acid component and a specific arom. diamine component. CONSTITUTION:A transparent soluble arom. polyimide polymer mainly contg. recurring units of formula II and having a logarithmic viscosity of 0.2 to 5.0 [0.5g/100ml solvent (N-methyl-2-pyrrolidone); 30 deg.C] is obtd. by polymn. and imidation of an arom. tetracarboxylic acid component contg. at least 80mol% 2,3,3',4'-biphenyltetracarboxylic acid(s) and an arom. diamine component contg. at least 80mol% bis(aminophenoxyphenyl) sulfone(s) of formula I at a substantially equimolar ratio. The polyimide polymer is homogeneously dissolved in an org. polar solvent(s) selected from among sulfoxide, formamide, acetamide, phosphoramide and pyrrolidone to form a soln. compsn.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a specific transparent aromatic polyimide, which is soluble in an organic polar solvent and is excellent in transparency and non-coloring property, uniformly dissolved in a specific organic polar solvent. And a transparent aromatic polyimide solution composition. The transparent aromatic polyimide is excellent in electrical properties, mechanical properties, heat resistance, and the like, and also has excellent transparency to light and the like, non-coloring property, and excellent solubility (solubility) in organic solvents. Aromatic polyimide solution compositions (varnishes) for forming a protective film for electrical insulation of various electric or electronic parts can be easily prepared. Therefore, the aromatic polyimid solution composition of the present invention is By coating the surface of various electric or electronic parts, a protective film for electric insulation having excellent performance can be easily formed.

[0002]

2. Description of the Related Art The use of aromatic polyimide as an electrically insulating protective film (interlayer insulating film, etc.) is well known in the electric or electronic material industry, for example, as disclosed in JP-A-48-34.
As disclosed in Japanese Patent Application Publication No. 686, Japanese Patent Application Laid-Open No. 49-40077, etc., heat resistance and insulation properties are obtained in an insulating film for a solid element, a material for forming a passivation film, an interlayer insulating film for a semiconductor integrated circuit, etc. Various proposals have already been made that a protective film made of polyimide is suitable because of its excellent properties such as.

However, since aromatic polyimide is generally difficult to dissolve in an organic solvent, a solution of a precursor of aromatic polyimide (aromatic polyamic acid) is used to form a coating film, and then a coating film is formed. It is necessary to heat the coating film at a fairly high temperature for a long time for drying and imidization to form an aromatic polyimide protective film, and the aromatic polyimide protective film is reproduced at a relatively low temperature. Since it could not be formed with good properties, there was a problem that the electrical or electronic material to be protected itself was thermally deteriorated.

On the other hand, as an aromatic polyimide soluble in an organic polar solvent, for example, a polyimide as described in Japanese Patent Publication No. 57-41491 is known. These aromatic polyimides are generally yellow. It is colored brown, reddish brown, etc., and its transparency to visible light, etc. was not sufficient, so it is not suitable when used as a material for image formation or as a protective film for optical sensors, solar cells, etc. there were.

[0005]

[Constituent requirements of the present invention] The present inventors have found that an aromatic polyimide that does not have the above-mentioned drawbacks, that is, an aromatic polyimide that has both excellent transparency and solubility, can be used as an organic polar solvent. As a result of diligent research on a solution composition that is uniformly dissolved, an aromatic tetracarboxylic acid component containing 2,3,3 ′, 4′-biphenyltetracarboxylic acid as a main component and bis (aminophenoxy-phenyl) sulfone Aromatic polyimides obtained by polymerizing and imidizing approximately equimolar amounts of aromatic diamine components whose main component is, have excellent solubility in organic polar solvents, and, moreover, to visible light The present invention has been completed by discovering that they have excellent transparency.

That is, the present invention relates to 2, 3, 3 ',
An aromatic tetracarboxylic acid component containing 80 mol% or more of 4'-biphenyltetracarboxylic acid, and a general formula I

[0007]

[Chemical 3] A bis (aminophenoxy-phenyl) sulfone represented by the formula (II), obtained by polymerization and imidization, from a substantially equimolar amount of the aromatic diamine component containing 80 mol% or more.

[0008]

[Chemical 4] Which is a polymer mainly containing a repeating unit represented by the formula: logarithmic viscosity [concentration; 0.5 g / 100 ml solvent (N-methyl-2-pyrrolidone), measurement temperature; 30
C] is 0.2 to 5.0, a transparent soluble aromatic polyimide,

Protection characterized by being uniformly dissolved in an organic polar solvent selected from the group consisting of sulfoxide solvents, formamide solvents, acetamide solvents, phosphoramide solvents, pyrrolidone solvents and lactone solvents. The present invention relates to a solution composition of an aromatic polyimide for forming a film.

The specific aromatic polyimide used in the present invention has sufficient solubility in organic polar solvents such as amide solvents (pyrrolidone solvents, formamide solvents, acetamide solvents, etc.). Therefore, consisting of the aromatic polyimide and the organic polar solvent,
The "solution composition (varnish) of the aromatic polyimide of the present invention" having storage stability and relatively low viscosity can be easily prepared.

The aromatic polyimide solution composition of the present invention is applied to the surface of various electric or electronic members, and then dried and heated at a relatively low temperature to obtain an excellent protective film (thickness: 0.5). (About 500 μm) can be easily formed.

Further, since the above-mentioned aromatic polyimide has an extremely excellent ability to transmit visible rays and the like and is excellent in transparency and non-coloring property, the solution composition of the present invention is conventionally yellow. , Various applications that could not be used due to coloring such as brown and reddish brown, for example, liquid crystal alignment films, protective materials for liquid crystal display devices, color filter materials for color liquid crystal panels, optical sensors, solar cells, etc. It can be preferably used for forming a protective film.

Furthermore, since the above-mentioned aromatic polyimide retains excellent performances in mechanical strength, heat resistance, electric insulation, etc. like the conventionally known aromatic polyimides, the solution composition of the present invention. Can be suitably used for surface protection of various electric or electronic materials, formation of interlayer insulating films, and the like.

[0014]

[Explanation of each requirement of the present invention] The above-mentioned aromatic polyimide is
An aromatic tetracarboxylic acid component containing 2,3,3 ′, 4′-biphenyltetracarboxylic acids in an amount of 80 mol% or more, preferably 90 mol% or more;

[0015]

[Chemical 5]

An aromatic diamine component containing 80 mol% or more, preferably 90 mol% or more of the bis (aminophenoxy-phenyl) sulfone represented by the formula (1) in a substantially equimolar amount in an organic polar solvent is used. High temperature (preferably about 1)
It is produced by heating at a temperature of 0 to 300 ° C.) and polymerizing and imidizing it in a single step, or alternatively, the above two components are approximately equimolar in an organic polar solvent, preferably about 80 ° C. or less. At a temperature of 0 to 60 ° C. to produce an aromatic polyamic acid (a precursor of aromatic polyimide), and imidize the aromatic polyamic acid under appropriate conditions to produce a transparent soluble polymer. It is an aromatic polyimide.

That is, the aromatic polyimide has the general formula II

[Chemical 6]

It is a high molecular weight soluble aromatic polyimide which mainly contains (60 mol% or more, particularly 80 mol% or more) of the repeating unit represented by and has transparency.

The above 2,3,3 ', 4'-biphenyltetracarboxylic acids include 2,3,3', 4'-biphenyltetracarboxylic acid or its acid dianhydride, or the above-mentioned aromatic tetracarboxylic acid. It may be an esterification product or salt of a carboxylic acid. In this invention, 2, 3, 3 ', 4'
-Biphenyltetracarboxylic acid or its dianhydride is optimal because it has excellent solubility in the aromatic polyimide obtained and the like.

The above-mentioned aromatic tetracarboxylic acid component is
It contains 2,3,3 ', 4'-biphenyltetracarboxylic acids in an amount of 80 mol% or more, preferably 90 mol% or more. For example, 3,3', 4,4'-benzophenonetetracarboxylic acid or an acid thereof. Dianhydride, 2,3,3 ', 4'
“Other aromatic tetracarboxylic acids” such as benzophenone tetracarboxylic acid or its acid dianhydride, pyromellitic acid or its acid dianhydride can be used together with the above-mentioned biphenyl tetracarboxylic acids. The usage ratio of the "other aromatic tetracarboxylic acids" is
It is less than 20 mol%, preferably less than 10 mol%, based on the wholly aromatic tetracarboxylic acid component.

Examples of the "bis (aminophenoxy-phenyl) sulfones represented by the above general formula" which are the main components of the aromatic diamine component include, for example, bis [4
Examples thereof include-(4'-aminophenoxy) phenyl] sulfone and bis [4- (3'-aminophenoxy) phenyl] sulfone. As the bis (aminophenoxy-phenyl) sulfone, at least one hydrogen atom of the benzene ring of the aromatic diamine compound is a suitable substituent (for example, a lower alkyl group such as a methyl group, an ethyl group or a propyl group). , A substituent such as an alkoxy group such as a methoxy group and an ethoxy group).

The aromatic diamine component contains the bis (aminophenoxy-phenyl) sulfones in an amount of 80 mol% or more, preferably 90 mol% or more. For example, paraphenylenediamine and metaphenylenediamine. , 2,4-diaminotoluene, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, o-tolidine, 1,4-bis (4-aminophenoxy) benzene, o-tolidine sulfone, etc. Aromatic diamine compounds and the like can be used together with the bis (aminophenoxy-phenyl) sulfones. The amount of the "other aromatic diamine compound" used is less than about 20 mol%, preferably less than 10 mol%, based on the total aromatic diamine component.

Examples of the organic polar solvent used in the above polymerization include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, and N. , N-dimethylacetamide, N, N
-Acetamide-based solvent such as diethylacetamide, N
-Pyrrolidone-based solvents such as methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, hexamethylene sulfolamide, γ-butyrolactone and the like, or phenol,
Phenol solvents such as o-, m- or p-cresol, xylenol, halogenated phenols (parachlorophenol, orthochlorophenol, parabromophenol, etc.), catechol and the like can be mentioned.

The aromatic polyimide used in the present invention is a high molecular weight polymer, for example, concentration: 0.
A solution of 5 g / 100 ml of a solvent (N-methyl-2-pyrrolidone) has a logarithmic viscosity (indicating the degree of polymerization of a polymer) measured at a measurement temperature of 30 ° C. of 0.2 to
It is 5.0, preferably about 0.3 to 3.0.

The above-mentioned aromatic polyimide is the above-mentioned sulfoxide-based solvent, formamide-based solvent, acetamide-based solvent, phosphoramide-based solvent used in the above-mentioned polymerization,
It is very easily dissolved in an organic polar solvent selected from the group consisting of pyrrolidone-based solvents and lactone-based solvents, or a mixed solvent in which xylene, ethyl cellosolve, diglyme, dioxane, etc. are partially blended in these organic polar solvents. Therefore, the aromatic polyimide is uniformly dissolved in the organic polar solvent at a concentration of about 1 to 30% by weight, particularly about 3 to 25% by weight, and the rotational viscosity at 25 ° C. is about 0.1 to 100%.
It is possible to prepare a solution of an aromatic polyimide having a viscosity of 000 poises, particularly 1 to 10000 poises (which becomes a varnish or a dope solution for film formation), that is, a "solution composition of an aromatic polyimide of the present invention".

The aromatic polyimide solution composition of the present invention may be a polymerization liquid of an aromatic polyimide obtained by polymerizing and imidizing a monomer component in an organic polar solvent in a single step as described above, Further, the polymerization solution may be diluted to an appropriate concentration with an organic polar solvent similar to the polymerization solvent. Alternatively, the aromatic polyimide solution composition of the present invention can be prepared by dissolving the aromatic polyimide powder once isolated as a powdery precipitate from the above-mentioned polymerization solution in the organic polar solvent.

The aromatic polyimide solution composition of the present invention can be applied, for example, to the surface of an object to be coated (circuit board, optical sensor, etc.) at room temperature or under heating by using a spin coater or a printer. By a suitable method to form a coating film of the composition (aromatic polyimide solution), and then coating the coating film at about 50 ° C., especially 60 to 25 ° C.
By drying at a temperature of 0 ° C., a transparent aromatic polyimide solidified film can be produced.

In the aromatic polyimide solution composition of the present invention, as the organic polar solvent, a sulfoxide solvent, a formamide solvent, an acetamide solvent, a pyrrolidone solvent, or a phosphoramide solvent such as hexamethylenephosphoramide is used. If a solvent is used,
The drying temperature is about 60 to 200 ° C, especially 80 to 180 ° C.
It is suitable because the temperature can be relatively low.

The aromatic polyimide of the present invention has excellent solubility in an organic polar solvent such as a pyrrolidone solvent as described above and is formed into a film having a thickness of about 30 μm or less, particularly 20 μm or less. In that case, the film is excellent in non-coloring property and transparency, and can be said to be substantially colorless and transparent.

[0030]

【Example】

Example 1 To 18.0 ml of N-methyl-2-pyrrolidone (NMP) was added 1.64 g of 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and bis [4- (4'-aminophenoxy). ) Phenyl] sulfone (2.43 g) was added, and the reaction solution was stirred at 20% with nitrogen gas flowing.
Polymerization was carried out at a reaction temperature of ° C for 5 hours to produce an aromatic polyamic acid.

Next, after adding 55.8 ml of NMP to the solution of the aromatic polyamic acid to dilute it, 11.14 g of acetic anhydride and 4.26 g of pyridine were added, and the mixture was imidized at 50 ° C. for 3 hours. , Aromatic polyimide was generated, and methanol was further added to this solution to precipitate the generated aromatic polyimide, which was then filtered to obtain aromatic polyimide powder.

The aromatic polyimide obtained as described above is dissolved in NMP at about 30 ° C., and the solubility of the polyimide (the aromatic polyimide powder is dissolved in the NMP solvent at 30 ° C. is the maximum concentration). And the aromatic polyimide powder is NM at 30 ° C. to a concentration of 14% by weight.
The dissolution time is shown so that it dissolves in the P solvent. ), And the logarithmic viscosity of this polyimide (concentration; 0.5 g / 10
0 ml solvent, measurement temperature; 30 ° C.) was measured.
The results are shown in Table 1.

The aromatic polyimide obtained as described above was dissolved in NMP at about 30 ° C. to prepare a uniform aromatic polyimide solution having a concentration of about 14% by weight. The rotational viscosity (25 ° C.) of the aromatic polyimide solution prepared as described above was measured, and the results are shown in Table 1.

Further, this aromatic polyimide solution is added to Si.
It is applied on a glass coated with O ₂ by using a spin coater (1000 to 3000 rpm) and at 80 ° C.
At 60 ° C., it was heated and dried to form an aromatic polyimide thin film having a thickness of about 5 μm. This thin film as it is or a film obtained by heat-treating this thin film in air at 350 ° C. for 30 minutes was recorded by a self-recording spectrophotometer (manufactured by Hitachi Ltd., 3
30) was used to measure the light transmittance of light having a wavelength of 400 nm and 440 nm. The color tone of the above-mentioned aromatic polyimide thin film (heat-treated film) was observed, and then the thermal decomposition starting temperature was measured using a calorimeter (manufactured by DuPont, Model 951). The measurement results are shown in Table 1.

Comparative Example 1 In 23.6 ml of N-methyl-2-pyrrolidone (NMP), 2.15 g of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and bis [4- (4' 3.17 g of -aminophenoxy) phenyl] sulfone was added, and the mixture was stirred for 5 hours at a reaction temperature of 20 ° C in a nitrogen atmosphere to carry out polymerization to produce an aromatic polyamic acid.

Next, 66.0 ml of NMP was further added to the solution of the aromatic polyamic acid to dilute it, and then 15.06 g of acetic anhydride and 5.76 g of pyridine were added to give a solution of 5.
An imidization reaction was carried out at 0 ° C. for 3 hours to produce an aromatic polyimide, and methanol was added to this solution to precipitate the produced aromatic polyimide, which was then filtered to obtain an aromatic polyimide powder. The solubility and the logarithmic viscosity of this aromatic polyimide were measured in the same manner as in Example 1, and the results are shown in Table 1.

The aromatic polyimide obtained as described above was dissolved in NMP at about 30 ° C. to prepare a uniform aromatic polyimide solution having a concentration of 14% by weight. The rotational viscosity (25 ° C.) of the aromatic polyimide solution prepared as described above was measured, and the results are shown in Table 1.

Further, an aromatic polyimide thin film was produced in the same manner as in Example 1 except that this aromatic polyimide solution was used. The light transmittance and the thermal decomposition starting temperature of this thin film were measured in the same manner as in Example 1, and the results are shown in Table 1.

The aromatic polyimide solution obtained in Comparative Example 1 became agar-like after 2 days, and the fluidity was remarkably deteriorated. Therefore, as shown in Table 1, the aromatic polyimide solution obtained in Comparative Example 1 has extremely high solution viscosity at 25 ° C. and loses fluidity in about 2 days. It was not practical as a polyimide solution composition for forming. In addition, the aromatic polyimide obtained in Comparative Example 1 had a long solubility in terms of solubility, and there was a problem in the preparation of the aromatic polyimide.

Example 2 24.0 ml of N-methyl-2-pyrrolidone (NMP)
To the above, 1.85 g of 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and 2.76 g of bis [4- (4'-aminophenoxy) phenyl] sulfone were added, and polymerization was performed at 180 ° C in a nitrogen atmosphere. The mixture was stirred at the reaction temperature for 5 hours, polymerization and imidization were carried out in one step, and an aromatic polyimide solution having a rotational viscosity (25 ° C.) of 110 poise was obtained.

The contained aromatic polyimide was recovered from the above solution, and the solubility and the logarithmic viscosity of the aromatic polyimide were measured in the same manner as in Example 1, and the results are shown in Table 1. Further, an aromatic polyimide thin film was produced in the same manner as in Example 1 except that the above aromatic polyimide solution was used. About this thin film, Example 1
The light transmittance and the thermal decomposition initiation temperature were measured in the same manner as in, and the results are shown in Table 1.

[0042]

[Table 1]

[0043]

The effects of the present invention are as follows:
Approximately equimolar amounts of an aromatic tetracarboxylic acid component containing 3,3 ′, 4′-biphenyltetracarboxylic acid as a main component and an aromatic diamine component containing bis (aminophenoxy-phenyl) sulfone as a main component, An aromatic polyimide having a specific repeating unit obtained by polymerization and imidization is a solution composition in which it is uniformly dissolved in an organic polar solvent, and the aromatic polyimide has excellent solubility in an organic polar solvent. Since it is a storage stable solution composition, and when a thin film is formed from the aromatic polyimide solution composition, the aromatic polyimide thin film has heat resistance, chemical resistance, and electrical insulation. Since the aromatic polyimid solution composition of the present invention has excellent transparency to visible light, it can be applied to the surface of various electric or electronic parts. The protective film for electrical insulation performance can be easily formed.

Claims (1)

Claims: 1. An aromatic tetracarboxylic acid component containing 80% by mole or more of 2,3,3 ', 4'-biphenyltetracarboxylic acid, and a compound represented by the general formula I: A bis (aminophenoxy-phenyl) sulfone represented by the formula: ## STR00002 ## obtained by polymerization and imidization from about an equimolar amount of an aromatic diamine component containing 80 mol% or more. Which is a polymer mainly containing a repeating unit represented by the formula: logarithmic viscosity [concentration; 0.5 g / 100 ml solvent (N-methyl-2-pyrrolidone), measurement temperature; 30
C] 0.2 to 5.0, a transparent soluble aromatic polyimide was selected from the group consisting of sulfoxide solvents, formamide solvents, acetamide solvents, phosphoramide solvents, pyrrolidone solvents and lactone solvents. A solution composition of an aromatic polyimide for forming a protective film, which is uniformly dissolved in an organic polar solvent.