JPH04283236A - Production of soluble polyimide - Google Patents

Abstract

PURPOSE:To obtain easily a solvent-soluble polyimide without the necessity for the precipitation and purification of the polymer by reacting an organic solvent solution of polyisoimide with a tert. amine. CONSTITUTION:A soluble polyimide is obtained by reacting an organic solvent solution of polyisoimide with a tert. amine. A desirable polyisoimide solution is one prepared by reacting a polyamic acid with a dihydroquinoline of the formula (wherein R<1> and R<2> represent each independently a 1-8C monovalent organic group) in an organic solvent.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing polyimides soluble in organic solvents.

0002

2. Description of the Related Art Polyimide resins have high heat resistance and excellent electrical and mechanical properties, so they are widely used as structural materials or electronic materials. However, since it has poor solubility in organic solvents, a method is usually used in which a polyamic acid solution, which is a precursor thereof, is applied to a base material and then fired. Firing is usually 250-450℃
This process simultaneously evaporates the solvent and dehydrates the amic acid to imidize it. However, since such a high firing temperature is required, firing cannot be performed in combination with a material having poor heat resistance. If a polyimide that is soluble in a solvent can be obtained, a polyimide coating can be obtained simply by evaporating the solvent, and baking at such high temperatures can be avoided, and the range of applications of polyimide can be expanded.

0003

[Problems to be Solved by the Invention] The commonly used method for producing soluble polyimide is to heat a polyamic acid solution with a specific structure to a high temperature of 100 to 200°C for a long period of time, and distill off the generated water. There is a method in which a large amount of an acid anhydride such as acetic anhydride and a tertiary amine such as pyridine are added to a polyamic acid solution at room temperature. However, heating a solution containing an organic solvent at high temperature for a long period of time causes significant discoloration, and addition of a large amount of acid anhydride significantly alters the properties of the solution, so soluble polyimides obtained by these methods are not used. This requires steps of polymer precipitation and purification. An object of the present invention is to provide a method for easily producing a solvent-soluble polyimide without performing such precipitation and purification.

0004

[Means for Solving the Problems] As a result of repeated research on the above-mentioned problems, the present inventors have discovered that soluble polyimide can be easily produced by adding a tertiary amine to an organic solvent solution of polyisoimide and causing the reaction. This led to the completion of the present invention. That is, the method for producing soluble polyimide of the present invention consists of adding a tertiary amine to a solution of polyisoimide in an organic solvent and causing the mixture to react. Here, the organic solvent solution of polyisoimide contains polyimide acid and a dihydroquinoline derivative represented by the above formula [Formula 1] (wherein R1 and R2 are each independently a monovalent organic group having 1 to 8 carbon atoms). A solution obtained by reaction in an organic solvent is preferred.

The polyisoimide used in the production method of the present invention has the formula [Chemical formula 2]

It is represented by [Chemical formula 2]. (However, R3 is a tetravalent organic group,
R4 is a divalent organic group, and n is a positive integer. )

The polyamic acid used in the production method of the present invention has the formula [Chemical formula 3]

It is represented by [Chemical formula 3]. (However, R3, R4 and n are as described above.) Polyamic acid is usually obtained by reacting a tetracarboxylic dianhydride and a diamine in an organic solvent. This reaction solution can be used as it is as a polyamic acid organic solvent solution in the production method of the present invention.

The dihydroquinoline derivative used in the production method of the present invention is represented by the formula [Formula 1]. As a specific example, N
-methoxycarbonyl-2-methoxy-1,2-dihydroquinoline, N-methoxycarbonyl-2-ethoxy-
1,2-dihydroquinoline, N-ethoxycarbonyl-
2-methoxy-1,2-dihydroquinoline, N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline, N-propoxycarbonyl-2-propoxy-1,
2-dihydroquinoline, N-isobutoxycarbonyl-
2-Methoxy-1,2-dihydroquinoline, N-isobutoxycarbonyl-2-ethoxy-1,2-dihydroquinoline, N-isobutoxycarbonyl-2-isobutoxy-1,2-dihydroquinoline, N-pentoxycarbonyl Examples include, but are not limited to, -2-pentoxy-1,2-dihydroquinoline.

Specific examples of tertiary amines used in the present invention include pyridine, 3-methylpyridine, 3-ethylpyridine, 4-methylpyridine, quinoline, isoquinoline, 2
, 6-lutidine, 3,5-lutidine, trimethylamine, triethylamine, N,N-dimethylbenzylamine, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole , 2-phenyl-4-methylimidazole, etc., but are not necessarily limited to these.

N-methyl-2-pyrrolidone is used as a solvent in the production method of the present invention and as a preferable solvent (hereinafter sometimes referred to as reaction solvent) for obtaining polyamic acid by the reaction of tetracarboxylic dianhydride and diamine. , N
, N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, tetramethylurea, pyridine, hexamethylphosphoramide, methylformamide, N-acetyl-2-pyrrolidone, 2-methoxyethanol, 2-ethoxy Ethanol, 2-butoxyethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, cyclopentanone,
Cyclohexanone, cresol, γ-butyrolactone, isophorone, N,N-diethylacetamide, N,N
-diethylformamide, N,N-dimethylmethoxyacetamide, tetrahydrofuran, N-acetyl-2
-pyrrolidone, N-acetyl-ε-caprolactam, tetrahydrothiophene dioxide {sulfolane (su
lforane)}. Moreover, a mixed solvent of the above organic solvents can be used. Furthermore, the above organic solvent can be replaced with other aprotic (neutral)
Organic solvents such as aromatic, cycloaliphatic or aliphatic hydrocarbons or their chlorinated derivatives (e.g. benzene, toluene, xylenes, cyclohexane, pentane,
(hexane, petroleum ether, methylene chloride, etc.) or dioxane, etc. can be used.

The method for producing polyisoimide used in the method for producing soluble polyimide of the present invention will be explained. By reacting a tetracarboxylic acid and a diamine in an organic solvent, a polyamic acid represented by the above [Chemical formula 3] can be obtained. By adding the dihydroquinoline derivative represented by the above formula [Chemical formula 1] to this solution, a polyisoimide shown by the above formula [Chemical formula 2] is obtained. The reaction formula is shown below.

embedded image (R1, R2, R3, R4 n are the same as above.)

[0011] Here, the by-produced carbon dioxide is removed from the system as a gas, and since the alcohol and quinoline are dissolved in the solvent, there is no need to remove them again. The reaction temperature is 0 to 100°C, preferably 0 to 50°C. Regarding the amount of dihydroquinoline derivative added to polyamic acid, if two molecules of dihydroquinoline derivative are added to one amic acid repeating unit, it is theoretically possible to convert all of the polyamic acid to polyisoimide. However, there is no particular problem even if the hydroquinoline derivative is added in excess, and a small amount may also be used. However, if the amount is small, a polymer containing a mixture of isoimide repeating units and amic acid repeating units will be obtained. Also, depending on the reaction conditions, some of the generated isoimide may be converted to imide, resulting in imide, isoimide,
and polymers containing repeating amic acid units may also be produced. Since this solution contains quinoline, which is a tertiary amine, the isoimide in the solution is gradually converted to imide, but the rate of conversion is often very slow. It is preferable to carry out the reaction by adding a class amine. Another method for producing isoimide is to carry out the reaction by adding a dehydrating agent such as N,N'-dihydrocarbyl-substituted carbodiimide, halogenated lower fatty acid anhydride, or lower fatty acid halide to polyamic acid.

A soluble polyimide can be obtained by the production method of the present invention, in which the above-mentioned tertiary amine is added to the polyisoimide solution obtained in this way and the reaction is carried out. The amount of tertiary amine added may be 10% or more of the isoimide group, but preferably 50 to 300%. The reaction temperature is 10-100°C, preferably 20-70°C. If the reaction temperature is too low, the imidization reaction will proceed slowly, and if it is too high, gelation may occur and the solution may lose fluidity, which is not preferable. Although the reaction time cannot be determined unconditionally depending on the type of tertiary amine added, the amount added, or the reaction time, it is 30 minutes or more, preferably about 2 to 20 hours.

[0013] The polyamic acid in the production method of the present invention is
It is usually synthesized by reacting a tetracarboxylic dianhydride and a diamine in an organic solvent.

The following compounds can be mentioned as tetracarboxylic dianhydrides, but they are not necessarily limited to these. Examples of the aromatic tetracarboxylic dianhydride include pyrrolimellitic dianhydride, 3,3′,4,4′
-Biphenyltetracarboxylic dianhydride, 2,2',3
, 3'-biphenyltetracarboxylic dianhydride, 2,3
, 3',4'-biphenyltetracarboxylic dianhydride,
3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,3,3',4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic acid dianhydride, bis-(3,4-dicarboxyphenyl)-ether dianhydride, bis-(3,
4-dicarboxyphenyl) sulfone dianhydride, 1,2
, 5,6-naphthalene tetracarboxylic dianhydride, 2,
3,6,7-naphthalene tetracarboxylic dianhydride, 2
, 2-bis(3,4-dicarboxyphenyl)tetrafluoropropane dianhydride, etc. Examples of alicyclic tetracarboxylic dianhydrides include cyclobutanetetracarboxylic dianhydride, methylcyclobutanetetracarboxylic dianhydride, etc. , as the aliphatic tetracarboxylic dianhydride, 1, 2,
Examples include 3,4-tetracarboxybutane dianhydride.

[0015] Examples of the diamine include the following compounds, but they are not necessarily limited to these. Aromatic diamines include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4
, 4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfide, 4,4'-di(meta-aminophenoxy)diphenylsulfone, 4,4'-di(
Para-aminophenoxy) diphenylsulfone, ortho-phenylenediamine, meta-phenylenediamine, para-phenylenediamine, benzidine, 3,3'-
Diaminobenzophenone, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl-2,2-propane, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 3,4'-diaminodiphenyl ether,
4,4′-bis(4-aminophenoxy)biphenyl,
2,2-bis{4-(4-aminophenoxy)phenyl}hexafluoropropane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3- Bis(3-aminophenoxy)benzene, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, 4,4'-diamino-3,3',5,5'-tetramethyl Diphenylmethane, 1,4-diaminotoluene, meta-xylylene diamine, 2,2'-dimethylbenzidine, etc.; examples of aliphatic diamines include trimethylene diamine, tetramethylene diamine, hexamethylene diamine, 2,11-dodecane diamine, etc. Examples of silicone diamines include bis(para-aminophenoxy)dimethylsilane, 1,4
-bis-(3-aminopropyldimethylsilyl)benzene, alicyclics such as 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, isophorone diamine, etc., and guanamines such as acetoguanamine, benzoguanamine, etc. I can give it to you. Moreover, the following compounds can be mentioned as the diamino polysiloxane.

[C5]

[C6]

[C7]

[Chemical formula 8]

[Chemical formula 9]

[Chemical formula 10]

[Chemical formula 11]

[Chemical formula 12]

[Chemical formula 13] (However, the above p is 1 to 100).

Next, the method of using the soluble polyimide obtained by the method of the present invention will be explained. The polyimide obtained by the production method of the present invention is obtained in a state dissolved in a solvent in most cases, so it can be used as it is. It is preferable to use the reaction solution as it is, concentrate it, or dilute it with a solvent. As the dilution solvent, the same solvent as the reaction solvent can be used. When forming a polyimide cured film from a solution containing a soluble polyimide obtained by the production method of the present invention, any known method may be used. For example, a cured film is obtained by applying a solution containing the soluble polyimide obtained by the method of the present invention onto a substrate such as a glass plate, copper plate, aluminum plate, or silicon wafer, and then baking it at a temperature of 100 to 400°C. be able to. However, since the soluble polyimide obtained by the method of the present invention is already an imidized polymer, it is only necessary to volatilize the solvent in the solution, and it is baked at a relatively low temperature of 100 to 200°C for several minutes to several hours. By performing this, a cured film can be obtained. In order to enable such low-temperature firing, all of the repeating units constituting the soluble polyimide do not need to be imidized, and may contain some amic acid units or isoimide units. Any coating method may be used, but usually spin coating,
The method is selected from a printing method, a spray coating method, a blade coating method, a dipping method, a roll coater method, etc.

The soluble polyimide obtained by the production method of the present invention can be used as various protective films for semiconductors, insulating films, alignment films for liquid crystals, base materials for color filters, protective films thereof, films, molding materials, etc. Conceivable.

The present invention will be explained in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited by these Examples.

(Example 1) After purging the system of a 1 liter flask equipped with a stirring device, a dropping funnel, a thermometer, a condenser, and a nitrogen purging device with nitrogen gas, N-methyl-2-pyrrolidone was purified by dehydration. (hereinafter abbreviated as NMP), 85.08 g of 1,1-bis{4-(4-aminophenoxyphenyl)}cyclobutane
, (0.189 mol) and 1-methyl,1,2,3,
39. 4-Tetracarboxycyclohexane dianhydride.
92 g (0.189 mol) was added to obtain a polyamide solution according to a conventional method. 93.39 g (0.378 mol) of N-ethoxycarbonyl, 2-ethoxy, 1,2-dihydroquinoline (hereinafter abbreviated as EEDQ) was added to this solution, and the reaction was carried out at 20°C for 10 hours to form a polyisoimide solution. Obtained. Furthermore, 48.7% of isoquinoline was added to this solution.
8 g (0.378 mol) was added and the reaction was carried out at 20° C. for 10 hours to obtain a pale brown transparent liquid. After spin-coating this solution onto a silicon wafer, it was coated at 50°C under reduced pressure for 2
A thin film was obtained by drying for 4 hours. When this film was peeled off from the wafer and the infrared absorption spectrum was measured, the result was 1780 cm-
Absorption based on imide groups was observed in 1 (Figure 1).

(Example 2) Using the same apparatus and method as in Example 1, 500 g of NMP, 28.34 g (0.142 mol) of 4,4'-diaminodiphenyl ether, 3,
52.13 g (0.16
2 mol) and 7.76 g (0.364 mol) of 4-aminophenyltrimethoxysilane (hereinafter abbreviated as APMS)
mol) to obtain a polyamic acid solution according to a conventional method. Add dicyclohexylcarbodiimide (D
After adding 62.66 g (0.304 mol) of acetate (abbreviated as CC) and carrying out a reaction at 25° C. for 3 hours, by-produced dicyclohexyl urea was removed by filtration to obtain a polyisoimide solution. Furthermore, 36.63 g of isoquinoline was added to this solution.
(0.284 mol) was added thereto, and the reaction was carried out at 40° C. for 4 hours to obtain a pale brown transparent solution. The polymer in this solution was treated in the same way and the infrared absorption spectrum was measured.
It was confirmed that soluble polyimide was obtained.

(Example 3) N,N-dimethylacetamide (hereinafter referred to as DMAC) was prepared using the same apparatus and method as in Example 1.
500g of ethylene glycol-bis-
53.43 g (0.13 g) of trimellitic anhydride ester
0 mol) and 56.32 g (0.130 mol) of bis{4-(3-aminophenoxyphenyl)}sulfone
were mixed and reacted according to a conventional method to obtain polyamic acid. Add 70.85 g (0.28 g) of EEDQ to this solution.
7 mol) was added and the reaction was carried out at 25°C for 15 hours to obtain a polyisoimide solution. Furthermore, 1-benzyl, 2-
34.81 g (0.195 mol) of methylimidazole
was added and the reaction was carried out at 25°C for 5 hours to obtain a pale brown transparent liquid. The polymer in this solution was treated in the same manner and its infrared absorption spectrum was measured, and it was confirmed that a soluble polyimide was obtained.

(Example 4) Using the same apparatus and method as in Example 1, 500 g of DMAC and 17.16 g of 3,3'-diaminophenyl sulfone (hereinafter abbreviated as DDS) were prepared.
g (0.069 mol), 44.54 g (0.069 mol) of BTDA.
138 mol) and 26.53 g (0.12 mol) of APMS
4 mol) and reacted according to a conventional method to obtain a polyamic acid solution. 51.34 g of DCC in this solution
(0.249 mol) was added thereto, and the reaction was carried out at 30°C for 10 hours to obtain a polyisoimide solution. Furthermore, 11.59 g (0.124 mol) of 4-methylpyridine was added to this solution, and the reaction was carried out at 25° C. for 10 hours to obtain a pale brown transparent liquid. The polymer in this solution was treated in the same manner and its infrared absorption spectrum was measured, and it was confirmed that a soluble polyimide was obtained.

(Example 5) Using the same apparatus and method as in Example 1, 25% of diethylene glycol dimethyl ether was prepared.
0 g, 12.84 g (0.052 mol) of DDS, ω,
42.08g (0.052 mol) of ω-bis(3-aminopropyl)polydimethylsiloxane and 33.32g (0.103 mol) of BTDA were mixed and reacted according to a conventional method to form a polyamic acid solution. Obtained. 51.14 g (0.207 mol) of EEDQ was added to this solution, and the reaction was carried out at 20° C. for 8 hours to obtain a polyisoimide solution. Furthermore, 33.39g (0.2g) of isoquinoline was added to this solution.
58 mol) was added thereto, and the reaction was carried out at 40°C for 3 hours to obtain a light brown transparent liquid. The polymer in this solution was treated in the same manner and its infrared absorption spectrum was measured, and it was confirmed that a soluble polyimide was obtained.

(Example 6) Using the same apparatus and method as in Example 1, 500 g of NMP, 2,2-bis-{4-(4
-aminophenoxyphenyl)} 43.31 g (0.084 mol) of hexafluoropropane, 3.70 g (0.017 mol) of 3-aminopropyltriethoxysilane (hereinafter abbreviated as APS-E) and 4,4 '-(hexafluoroisopropylidene)diphthalic anhydride 41.
23 g (0.093 mol) were mixed and reacted according to a conventional method to obtain a polyamic acid solution. Add EE to this solution
Add 50.50 g (0.204 mol) of DQ,
The reaction was carried out at ℃ for 10 hours to obtain a polyisoimide solution. Furthermore, 11.99 g (0.093 g) of isoquinoline was added to this solution.
mol) was added thereto, and the reaction was carried out at 25°C for 3 hours to obtain a light brown transparent liquid. The polymer in this solution was treated in the same manner and its infrared absorption spectrum was measured, and it was confirmed that a soluble polyimide was obtained.

(Example 7) Using the same apparatus and method as in Example 1, 500 g of NMP and 46.39 g (0.0
．． 187 mol), 16.55 g (0.07 mol) of APS-S
5 mol) and 103.73 g (0.234
mol) and reacted according to a conventional method to obtain a polyamic acid solution. This solution has an EEDQ of 127.05
g (0.514 mol) was added and the reaction was carried out at 30°C for 10 hours to obtain a polyisoimide solution. Furthermore, 60.33 g (0.467 mol) of isoquinoline was added to this solution, and 2
The reaction was carried out at 5°C for 5 hours to obtain a pale brown transparent liquid. The polymer in this solution was treated in the same manner and its infrared absorption spectrum was measured, and it was confirmed that a soluble polyimide was obtained.

(Comparative Example 1) The reaction was carried out in the same manner as in Example 7 except that isoquinoline was not added to obtain a light brown solution. The polymer in this solution was treated in the same manner and the infrared absorption spectrum was measured. As a result, no absorption of imide groups was observed.
Isoimide absorption was observed at 800 cm-1.

[0027]

[Effect of the invention] The method for producing soluble polyimide of the present invention is as follows:
The catalyst used in the imidization reaction is also less dangerous, and there is no need for a precipitation purification process, so the resulting solution can be put to practical use as is, which is highly effective. In addition, since a polyimide film can be formed from the obtained soluble polyimide simply by volatilizing the solvent, a coating film can be formed even on a substrate with poor heat resistance, which has a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is an infrared absorption spectrum of the soluble polyimide of the present invention.

Claims (2)

[Claims] 1. A method for producing a soluble polyimide, which comprises adding a tertiary amine to a solution of polyisoimide in an organic solvent and causing a reaction. 2. The production of a soluble polyamide according to claim 1, wherein the organic solvent solution of polyisoimide is a solution obtained by reacting a polyamic acid and a dihydroquinoline derivative represented by the following formula (Chemical formula 1) in an organic solvent. Law. [Chemical formula 1]