JPH0971646A - Production of polyimide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a polyimide by a new method using a hydrocarbon as a reaction solvent, capable of completing a reaction in a short time at a low temperature, having improved workability and reliability because of the easy removal of the solvent and of a low cost on an industrial scale. SOLUTION: (A) A tetracarboxylic acid dianhydride or its diesterdicarboxylic acid derivative is made to react with (B) a diamino compound in a hydrocarbon solvent (preferably, toluene or xylene). Further, the component B is preferably a compound of formula I [X is a 1-20C hydrocarbon or a sulfur atom; R is a halogen, a 1-6C hydrocarbon or a 1-6C halogen-containing hydrocarbon; (a)=0-4] e.g. 1,1-bis[4-(4-aminophenoxy)-3-t-butyl-6-methylphenyl]butane}, and the component A is preferably a compound of formula II (Y is a >=2C tetravalent organic group) (e.g. pyromellitic dianhydride).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing a polyimide, and more specifically, it has various physical properties such as high heat resistance, high adhesiveness, good insulating property, low hygroscopicity, low dielectric property and processing. The present invention relates to a method for obtaining a polyimide having excellent properties under an easy and inexpensive production condition by reacting a tetracarboxylic dianhydride or its derivative with a diamino compound in a hydrocarbon solvent.

[0002]

2. Description of the Related Art Polyimide is widely used in the fields of electricity and electronics because of its high heat resistance and its excellent mechanical strength and electrical insulation. A conventional method for producing a polyimide is to react a functional derivative of a tetracarboxylic acid dianhydride or a tetracarboxylic acid dianhydride represented by a dialkyl ester dicarboxylic acid with a diamino compound or a diisocyanate in an organic solvent. However, polyimide and its precursor polyamic acid generally have poor solubility, and a polar solvent having high solubility in the reaction solvent, for example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide or other amide-based solvent, Jig Lime, 1,
Ether-based solvents such as 4-dioxane and tetrahydrofuran, phenol-based solvents such as cresol and chlorophenol, lactones such as γ-butyrolactone, nitrobenzene, benzonitrile and pyridine are used. However, these solvents have many disadvantages. For example,
The amide-based solvent usually used for polyimide synthesis has high workability because it requires high-temperature drying in order to completely remove it from the polyimide after molding because it has high affinity with polyimide and its precursor polyamic acid. In addition to the possibility of foaming due to the residual solvent, it is not preferable in that it has high hygroscopicity, so whitening easily occurs during molding, and that the solvent itself is expensive. Phenolic solvents have a strong irritating odor and are irritating to the skin. In addition, chlorine-containing solvents are not preferable for electrical and electronic applications because there is a risk of corrosion due to chlorine contained therein.

In the case of synthesizing a soluble polyimide by a one-pot synthesis method which is a simple synthesis method, a high boiling point reaction solvent such as N-methyl-2- is used in order to complete imidization and obtain a high molecular weight polyimide. It is necessary to use pyrrolidone, m-cresol, benzonitrile, nitrobenzene, etc., while removing water produced as a by-product at a high temperature of 200 ° C. or higher outside the reaction system. In this case, since the reaction temperature is high, it is troublesome in work and in terms of a synthesis apparatus, and the solvent itself is expensive. Therefore, an industrially easier and cheaper method is desirable.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a polyimide in a solvent which is easy to remove the solvent, has a low hygroscopic property, and has a low boiling point and is inexpensive.

[0005]

Means for Solving the Problems As a result of intensive investigations by the present inventors, it has been found that the use of hydrocarbon as a reaction solvent can achieve the above-mentioned object and that a polyimide having a specific structure can be modified without modification. The present invention was completed based on the finding that it retains solvent solubility even after being formed, and is particularly well dissolved in a hydrocarbon solvent. That is, the present invention relates to a method for producing a polyimide, which comprises reacting a tetracarboxylic dianhydride or its diester dicarboxylic acid derivative with a diamino compound in a hydrocarbon solvent.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The polyimide produced by the present invention has the general formula (1)

[0007]

Embedded image (In the formula, X represents a hydrocarbon group having 1 to 20 carbon atoms or a sulfur atom. R represents a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms or a halogen-containing hydrocarbon group having 1 to 6 carbon atoms,
a is an integer of 0 to 4 and represents the number of substituents. However, multiple R
And a may independently have different substituents and values. ) And a diamino compound represented by the general formula (2)

[0008]

[Chemical 6] (In the formula, Y represents a tetravalent organic group having 2 or more carbon atoms.) Desirably, it is obtained by reacting a tetracarboxylic acid dianhydride.

In the general formula (1), examples of the halogen atom used as R include fluorine, chlorine, bromine and iodine, and a hydrocarbon group having 1 to 6 carbon atoms and a halogen-containing compound having 1 to 6 carbon atoms. As the hydrocarbon group, methyl,
Hydrocarbon groups such as ethyl, propyl, butyl, pentyl, hexyl linear or branched alkyl groups, cyclohexyl groups, phenyl groups, and groups in which one or more hydrogen atoms of these hydrocarbon groups are substituted with halogen atoms. Is mentioned.

In the general formula (1), the hydrocarbon group having 1 to 20 carbon atoms used as X has 1 to 6 carbon atoms.
And an alkylene group having 2 to 14 carbon atoms, a phenylalkylidene group having 7 to 20 carbon atoms, or a hydrocarbon group having 5 to 20 carbon atoms and containing an alicyclic structure. Representative examples of the alkylene group having 1 to 6 carbon atoms include a methylene group and an ethylene group, and representative examples of the alkylidene group having 2 to 14 carbon atoms include an ethylidene group, a propylidene group, a butylidene group, a pentylidene group and a hexylidene group. Typical examples of a linear or branched alkylidene group such as a heptylidene group and a phenylalkylidene group having 7 to 20 carbon atoms include
Examples thereof include linear or branched phenylalkylidene groups such as phenylmethylidene group, phenylethylidene group, and phenylpropylidene group. Moreover, as a typical example of a C5-C20 hydrocarbon group containing an alicyclic structure, there may be mentioned formulas (b), (c), (d), (e), (f) or (g).

[0011]

[Chemical 7] And groups in which one or more hydrogen atoms in these alicyclic groups are substituted with an alkyl group such as a methyl group or an ethyl group. Among these, the groups represented by the formulas (b), (c) and (d) are preferable. Furthermore, among the diamino compounds represented by the general formula (1), those represented by the formula (a)

[0012]

Embedded image (In the formula, X represents a butylidene group or a sulfur atom) is also a preferred group of compounds.

Typical examples of the diamino compound represented by the general formula (1) are as follows. Bis [4- (4-aminophenoxy) -3-t-butyl-6-methylphenyl] sulfide, bis [3- (4-aminophenoxy)
-3-t-butyl-6-methylphenyl] sulfide,
1,1-bis [4- (4-aminophenoxy) -3-t
-Butyl-6-methylphenyl] butane, 1,1-bis [3- (4-aminophenoxy) -3-t-butyl-6
-Methylphenyl] butane, 1,1-bis [4- (4-
Aminophenoxy) -3-t-butyl-6-methylphenyl] pentane, 1,1-bis [3- (4-aminophenoxy) -3-t-butyl-6-methylphenyl] pentane, 1,1-bis [4- (4-aminophenoxy)-
3-t-butyl-6-methylphenyl] hexane, 1,
1-bis [3- (4-aminophenoxy) -3-t-butyl-6-methylphenyl] hexane, 1,1-bis [4- (4-aminophenoxy) -3-t-butyl-6
-Methylphenyl] heptane, 1,1-bis [3- (4
-Aminophenoxy) -3-t-butyl-6-methylphenyl] heptane, bis [4- (4-aminophenoxy) phenyl] menthane, bis [2- (4-aminophenoxy) phenyl] mentane, 1- [2 -(4-Aminophenoxy) phenyl] -8- [4- (4-aminophenoxy) phenyl] menthane, bis [4- (3-aminophenoxy) phenyl] mentane, bis [2- (3-aminophenoxy) phenyl ] Mentan, 1- [2- (3
-Aminophenoxy) phenyl] -8- [4- (3-aminophenoxy) phenyl] menthane, bis [4- (4
-Aminophenoxy) -3-methylphenyl] menthane, bis [4- (4-aminophenoxy) -3,5-dimethylphenyl] mentane, bis [4- (4-aminophenoxy) -3-butyl-6-methyl Phenyl] menthane, bis [4- (4-amino-5-methylphenoxy)
-3-Methylphenyl] menthane, bis [4- (4-amino-5-methylphenoxy) -3,5-dimethylphenyl] mentane, bis [4- (4-amino-5-methylphenoxy) -3-butyl -6-Methylphenyl] menthane, bis [2- (4-aminophenoxy) -3-methylphenyl] mentane, 1- [2- (4-aminophenoxy) -3-methylphenyl] -8- [4- ( 4-aminophenoxy) -3-methylphenyl] menthane, bis [4- (4-aminophenoxy) phenyl] tricyclo [5,2,1,0 ^2,6 ] decane, bis [2- (4-aminophenoxy) Phenyl] tricyclo [5,2,1,0
^2,6 ] decane, [2- (4-aminophenoxy) phenyl]-[4- (4-aminophenoxy) phenyl] tricyclo [5,2,1,0 ^2,6 ] decane, bis [4- (3
-Aminophenoxy) phenyl] tricyclo [5,2,2]
1,0 ^2,6] decane, bis [2- (3-aminophenoxy) phenyl] tricyclo [5,2,1,0 ^2,6] decane, [2- (3-aminophenoxy) phenyl] - [4
-(3-Aminophenoxy) phenyl] tricyclo [5,2,1,0 ^2,6 ] decane, bis [4- (4-aminophenoxy) -3-methylphenyl] tricyclo [5,2,1,0 ^{2 , 6} ] decane, bis [4- (4-aminophenoxy) -3,5-dimethylphenyl] tricyclo [5,2,1,0 ^2,6 ] decane, bis [4- (4-aminophenoxy) -3 -Butyl-6-methylphenyl]
Tricyclo [5,2,1,0 ^2,6 ] decane, bis [4-
(4-Amino-5-methylphenoxy) -3-methylphenyl] tricyclo [5,2,1,0 ^2,6 ] decane, bis [4- (4-amino-5-methylphenoxy) -3,
5-Dimethylphenyl] tricyclo [5,2,1,0
^2,6 ] decane, bis [4- (4-amino-5-methylphenoxy) -3-butyl-6-methylphenyl] tricyclo [5,2,1,0 ^2,6 ] decane, bis [2- ( 4-
Aminophenoxy) -3-methylphenyl] tricyclo [5,2,1,0 ^2,6 ] decane, [2- (4-aminophenoxy) -3-methylphenyl]-[4- (4-aminophenoxy)- 3-Methylphenyl] tricyclo [5,2,1,0 ^2,6 ] decane and the like are exemplified. Among these, 1,1-bis [4- (4-aminophenoxy) -3-t-butyl-6-methylphenyl] butane,
Bis [4- (4-aminophenoxy) phenyl] menthane and bis [4- (4-aminophenoxy) -3,5
-Dimethylphenyl] tricyclo [5,2,1,
0 ^2,6 ] decane is preferred.

The diamino compound represented by the general formula (1) may be mixed with another diamino compound. Representative examples of other diamino compounds include the following. m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,3'-diaminodiphenyl ether, 3,
4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,
4'-diaminodiphenylmethane, 3,3 ', 5,5'
-Tetrabromo-4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenyl sulfide, 3,
4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 1,3-
Examples include bis (4-aminophenoxy) benzene and 1,4-bis (4-aminophenoxy) benzene. These diamino compounds may be used alone or in combination of two or more, but in order to obtain good solubility, the diamino compound represented by the general formula (1) is 70
It is desirable to occupy at least%.

Any tetracarboxylic acid dianhydride represented by the general formula (2) can be applied as long as it can undergo a condensation reaction with the above-mentioned diamino compound. Typical examples are as follows. Can be mentioned. Ethylene tetracarboxylic dianhydride, cyclopentane carboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3 ′
-Benzophenone tetracarboxylic dianhydride, 3,
3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-diphenylsulfone tetracarboxylic dianhydride Anhydride, 3,3 ', 4,4'-diphenylhexafluoroisopropylidene tetracarboxylic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride, 2,
3,6,7-naphthalenetetracarboxylic dianhydride,
1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1, 2,7,8-phenanthracene tetracarboxylic acid dianhydride, 4- (1,2-dicarboxylethyl) -4-methyl-1,2,3,4-tetrahydro-
1,2-Naphthalenedicarboxylic acid dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 5- (1,2-dicarboxyethyl) -3-methyl -1,2,5,6-tetrahydrophthalic dianhydride, 6-methyl-tricyclo [6,6
2,2,0 ^2,7 ] -dodeca-6,11-diene-3,
Examples include 4,9,10-tetracarboxylic dianhydride and the like. These tetracarboxylic dianhydrides may be used alone or in admixture of two or more.

Hydrocarbons used in the present invention include cyclohexane, benzene, toluene, ethylbenzene, xylene, o-xylene, m-xylene, p-xylene,
Mesitylene, cumene, o-cymene, m-cymene, p-cymene, solvent naphtha and the like can be mentioned. Among these, xylenes are particularly preferable. You may use these solvent individually or in mixture of 2 or more types. The concentration is 1 to the sum of the weights of the diamino compound and the tetracarboxylic dianhydride.
It is prepared to be about 50% by weight, preferably about 5 to 30% by weight.

Hydrocarbons used in the present invention include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, diglyme, and methylisobutyl for controlling solubility and reaction temperature. Ketone,
Although compatible polar solvents such as m-cresol and γ-butyrolactone may be mixed, considering the gist of the present invention,
It is better to keep the mixing ratio to about 30% of the total amount of the solvent.

As the method for synthesizing the polyimide in the present invention, any method can be applied as long as it is a method capable of synthesizing a polyimide. Among them, a so-called thermal reaction of a diamino compound and tetracarboxylic dianhydride in a solvent The one-pot synthesis method is preferred. The water produced is azeotropically distilled with the reaction solvent and discharged out of the system. Prior to the synthesis of the polyimide, water in the raw material is sufficiently removed by a known method,
It is preferable to carry out the reaction under a stream of dry nitrogen. The reaction pressure is not particularly limited, and the reaction can be sufficiently performed at normal pressure. The reaction time varies depending on the type of diamino compound and tetracarboxylic dianhydride used, the solvent and the reaction temperature, but is usually 5 to 2
4 hours.

The molar ratio of the diamino compound and the tetracarboxylic dianhydride is selected from the range of 1 / 0.5 to 1/2,
When it is desired to obtain a high molecular weight product, the reaction is carried out at a molar ratio close to 1/1. To control the molecular weight, add an aromatic monoamino compound or an aromatic dicarboxylic acid anhydride,
A method of making the ends non-reactive can also be used. Benzoic acid, isoquinoline or the like may be added as a catalyst for promoting the reaction. Further, in order to improve the physical properties of the obtained polyimide such as imparting flame resistance and adhesiveness, an appropriate reactive or non-reactive additive may be added.

The obtained polyimide can be used as it is for forming a film or the like with the reaction solution. Alternatively, the reaction solution may be poured into a poor solvent such as methanol to precipitate the generated polyimide to give a powder, and the powder may be used as it is or may be redissolved in an appropriate solvent for molding.

The applications of the obtained polyimide are various protective films for electric and electronic parts, interlayer insulating films, base films for flexible printed boards and TAB tapes, heat resistant adhesives, alignment films for liquid crystal display devices, gas separation films. Examples of the material include, but are not limited to, a transparent film, a molding resin, and the like.

[0022]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. The measuring methods and devices used in the examples and comparative examples are as follows. An o-xylene solution having an intrinsic viscosity η _{inh .} : 0.5 g / dl was prepared, and the drop time was measured in a thermostat at 30 ° C. using an Ubbelohde viscometer, and calculated by the following formula. η _inh. = [ln (t / t ₀ )] / 0.5 [dl / g] where t: drop time (seconds) of solution measured by viscometer t ₀ : drop of solvent similarly measured Time (second) Infrared absorption spectrum: IR-700 manufactured by JASCO Corporation
It was measured using the device.

Example 1 2.18 g of pyromellitic dianhydride (0. 0%) was placed in a 100 ml four-necked flask equipped with a nitrogen gas introduction tube, a thermometer, a stirrer, and a Dean-Stark tube filled with o-xylene.
01 mol) and 24.3 g of o-xylene,
To a place where the temperature was raised to 135 ° C under a nitrogen stream and dissolved,
1,1-bis [4- (4-aminophenoxy) -3-t
-Butyl-6-methylphenyl] butane 5.64 g
A solution prepared by dissolving (0.01 mol) in 20.0 g of o-xylene was added dropwise while paying attention to heat generation. Polyamic acid was deposited at the same time as the dropping, but the deposit was dissolved in about 5 minutes to form a uniform solution. While water generated by imidization was removed from the system by azeotropic distillation, the mixture was stirred at 140 ° C. for 8 hours under a nitrogen stream. When the infrared absorption spectrum was measured, the characteristic absorption bands of the 5-membered ring imide group were 1720 cm ⁻¹ and 178 cm ^−1.
Absorption around 0 cm ^-1 was observed, but no absorption around 1650 cm ^{-1 due} to the amide group was observed, confirming the completion of imidization. The obtained polyimide has an intrinsic viscosity of 0.6
It was 0 dl / g.

Example 2 A 100 ml four-necked flask equipped with a nitrogen gas introduction tube, a thermometer, a stirrer, and a Dean-Stark tube filled with o-xylene was charged with 3,3 ', 4,4'-biphenyltetracarboxylic acid. 2.94 g (0.01 mol) of dianhydride and 28.6 g of o-xylene were charged, and the temperature was 135 ° C. under a nitrogen stream.
When the temperature was raised to (suspension state where the acid dianhydride was not completely dissolved), 1,1-bis [4- (4-aminophenoxy)]
-3-t-Butyl-6-methylphenyl] butane 5.6
A solution prepared by dissolving 4 g (0.01 mol) in 20.0 g of o-xylene was added dropwise while paying attention to heat generation. Polyamic acid was deposited at the same time as the dropping, but the deposit was dissolved in about 20 minutes to form a uniform solution. While removing water generated by imidization from the system by azeotropic distillation, the mixture was stirred at 140 ° C. for 8 hours in a nitrogen stream, and infrared absorption spectrum was measured to confirm completion of imidization. The intrinsic viscosity of the obtained polyimide is 0.55
It was dl / g.

Comparative Example 1 100 ml equipped with a nitrogen gas introducing pipe, a thermometer and a stirring device
In a 4-necked flask, 5.64 g (0.01 mol) of 1,1-bis [4- (4-aminophenoxy) -3-t-butyl-6-methylphenyl] butane and N-methyl-
2-pyrrolidone 44.3 g was charged and dissolved, and then pyromellitic dianhydride 2.18 g (0.01 mo
1) was charged and stirred overnight at room temperature under a nitrogen stream to obtain a polyamic acid solution. The intrinsic viscosity of the obtained polyamic acid is
When a 0.5 g / dl N-methyl-2-pyrrolidone solution was prepared and measured in the same manner, it was 0.63 dl / g. Next, the temperature of the polyamic acid solution was raised to 140 ° C., and the mixture was stirred for 20 hours while removing the water produced under a nitrogen stream from the system along with nitrogen, but imidization was not completed.

Comparative Example 2 A polyamic acid solution was obtained in the same manner as in Comparative Example 1, and the reaction temperature at which imidization was completed in the same 8 hours as in Example 1 was examined. As a result, a reaction temperature of 190 ° C. was necessary. The intrinsic viscosity of the polyimide obtained at this time was 0.57 dl / g.

The polyimide reaction solutions obtained in Examples 1 and 2 and Comparative Example 2 were cast on a glass plate. The solution obtained in Comparative Example 2 showed whitening even after 3 minutes from casting, but the solutions obtained in Examples 1 and 2 did not show whitening. The cast solutions of the solutions obtained in Examples 1 and 2 were stored in a ventilated oven at 150 ° C. for 1 hour,
The solution obtained in Comparative Example 2 was cast under reduced pressure.
After drying at 00 ℃ for 3 hours, peeling off, 30μ each
An m-thick polyimide film was obtained. The appearance of each of the obtained films was good with no voids or cloudiness observed.

[0028]

As described above, in the method for producing a polyimide according to the present invention, the reaction can be completed in a hydrocarbon solvent at a low temperature in a short time, and the solvent can be easily removed to improve workability and workability. The reliability is improved, and the apparatus related to manufacturing and the like can be simplified, which is industrially useful.

[Brief description of drawings]

FIG. 1 shows an infrared absorption spectrum of a polyimide of Synthesis Example 1 of the present invention.

FIG. 2 shows an infrared absorption spectrum of the polyimide of Synthesis Example 2 of the present invention.

Claims (6)

[Claims] 1. A process for producing a polyimide, which comprises reacting a tetracarboxylic dianhydride or its diester dicarboxylic acid derivative with a diamino compound in a hydrocarbon solvent. 2. A diamino compound is represented by the general formula (1): (In the formula, X represents a hydrocarbon group having 1 to 20 carbon atoms or a sulfur atom. R represents a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms or a halogen-containing hydrocarbon group having 1 to 6 carbon atoms,
a is an integer of 0 to 4 and represents the number of substituents. However, multiple R
And a may independently have different substituents and values. ), Wherein the tetracarboxylic acid dianhydride is represented by the general formula (2): The manufacturing method according to claim 1, which is a compound represented by the formula (Y represents a tetravalent organic group having 2 or more carbon atoms). 3. A diamino compound represented by the general formula (1) is represented by the formula (a): (In the formula, X represents a butylidene group or a sulfur atom.) The method for producing a polyimide according to claim 2. 4. In the general formula (1), X is the formula (b),
(C) or (d) The method for producing a polyimide according to claim 2, which is represented by: 5. The amino group of the general formula (1) with respect to the substitution position of the ether oxygen atom is in the para position.
3. The method for producing a polyimide according to 3 or 4. 6. The production method according to claim 1, wherein the hydrocarbon solvent is toluene or xylene.