JPH0710993A - Heat-resistant resin, its production and varnish containing the same - Google Patents

Abstract

PURPOSE:To obtain a heat-resistant high-light-transmittance polyimide resin which is a copolyimide comprising specified repeating units and produced by reacting a tetracarboxylic anhydride with a diisocyanate in a polar solvent. CONSTITUTION:An aromatic tetracarboxylic anhydride such as diphenyl ether 3,3'-4,4'-tetracarboxylic anhydride is reacted with a diamine of formula I (wherein R1 and R2 are each H or 1-4C alkyl) or the corresponding diisocyanate in a nonamidic polar solvent having a permittivity of 5 or above desirably 15 or above at 20 deg.C or 25 deg.C for example diglyme to produce a copolyimide comprising repeating units of formulas II and III (wherein R0 is O, CO or the like; and Ar is a specified bivalent organic group). This polyimide is not only heat-resistant but also soluble in a low-boslong lawly hygroscopic solvent and can give a polyimide resin molding having a markedly high light transmittance. Further, it can give varnishes when dissolved in nonamidic solvents such as dioxane and tetrahydrofuran as well as dimethylacetamide, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel polyimide resin, a method for producing the same and a varnish containing the same. More specifically, it is possible to provide a molded product having a significantly high light transmittance, and a polyimide resin soluble in a low hygroscopic solvent,
The manufacturing method and the varnish containing the same.

[0002]

2. Description of the Related Art Polyimide resins are widely used as heat resistant fibers, films, molding materials and the like because of their excellent mechanical properties and heat resistance. However, since the heat-resistant polyimide currently used is only dissolved in a highly hygroscopic amide-based solvent, its temporal stability during molding is poor.
Further, during molding such as wet spinning, it is difficult to bring out the excellent mechanical properties originally possessed by polyimide, because the water produced by the solvent absorbs water, resulting in whitening or voids in the product. It was Further, in general, a heat-resistant polyimide product is colored in dark yellowish brown, and when it is molded into a fiber or the like, its coloring property is significantly limited, which is a drawback. Further, the dried film after coating is also excellent in transparency, but it is colored in yellow, which is not yet satisfactory in the field of liquid crystal alignment film and the like which requires colorless transparency.

[0003]

The object of the present invention is to provide a product which is soluble in a solvent having a low boiling point and a low hygroscopicity in addition to the heat resistance inherent in polyimide, and which has a remarkably high light transmittance. It is to provide a polyimide resin.

[0004]

[Means for Solving the Problems] The present inventors have accomplished the present invention as a result of intensive studies for achieving the above-mentioned object.
That is, the present invention provides the following general formula (I):

[0005]

[Chemical 10]

[Wherein R⁰Is -O-, -SO₂-, -C
O-, -CO-OR^Four-O-CO- (In the formula, R^FourIs charcoal
R1 represents an alkylene having a prime number of 1 to 4) or a direct bond.
¹, R ²May be the same or different, each
Hydrogen or an alkyl group having 1 to 4 carbon atoms]
And the following general formula (II):

[0007]

[Chemical 11]

[In the formula, R ⁰ 'is --O--, --SO _2- , --C
O -, - CO-O- R 4 '( wherein, R ⁴ -O-CO-' represents an alkylene group having 1 to 4 carbon atoms), or a direct bond,
Ar represents a divalent organic group], a copolymerized polyimide having a repeating unit represented by the following formula, a method for producing the same, and a polyimide varnish obtained by dissolving the same in a polar solvent.

R ¹ and R ² in the repeating unit represented by the general formula (I) may be the same or different and each is hydrogen, an alkyl group having 1 to 4 carbon atoms, preferably hydrogen and a methyl group. . R ⁰ and R ⁰ ′ in the repeating units represented by the general formulas (I) and (II) are respectively —O—, —SO ₂ —, —CO—, —CO—O—R ⁴
-O-CO- (in the formula, R ⁴ represents an alkylene having 1 to 4, preferably 2 to 4 carbon atoms) or a direct bond. Preferred R ⁰ and R ⁰ ′ include a sulfonyl bond. Ar in the repeating unit represented by the general formula (II) is a divalent organic group. Preferred Ar is the compound of formula (II
I), (IV), (V), (VI), (VII), (V
Examples thereof include organic groups represented by III) or (XI).

[0010]

[Chemical 12]

[0011]

[Chemical 13]

[0012]

[Chemical 14]

[0013]

[Chemical 15]

[0014]

[Chemical 16]

[0015]

[Chemical 17]

[0016]

[Chemical 18]

The molar ratio of the repeating units (I) and (II) varies depending on the composition, but (I) :( II) is 9
The range of 0:10 to 30:70 is preferable. In particular,
When Ar is a polyimide having the repeating unit (II) of the formula (III), the above molar ratio is 60:40 to 30:
70, 50:50 to 30: 7 when Ar is of the formula (VI)
0, 80:20 to 50:50 when Ar is the formula (V),
When Ar is the formula (VI), 80:20 to 60:40, A
When r is formula (VII), 90:10 to 60:40, A
When r is formula (VIII), 60:40 to 30:70,
When Ar has the formula (IX), it is preferably 90:10 to 60:40.

The polyimide of the present invention can be polymerized in a solvent having a relatively low hygroscopicity, and can provide a product having a remarkably high light transmittance without impairing heat resistance. That is,
The polyimide of the present invention is a non-amide solvent other than the highly hygroscopic amide solvent such as dimethylformamide, dimethylacetamide and N-methyl-2-pyrrolidone,
When tetracarboxylic acid is reacted with diamine or diisocyanate in a solvent having a relatively large dielectric constant, it can be easily obtained.

The polyimide of the present invention can be synthesized by a usual method such as a diamine method and an isocyanate method, but the isocyanate method is advantageous from the viewpoints of polymerizability and cost. When the polyimide of the present invention is produced by the isocyanate method, diglyme that could not be conventionally used, ether solvents such as tetrahydrofuran, cyclohexanone, ketone solvents such as methyl ethyl ketone, propionitrile, nitrile solvents such as acetonitrile, nitromethane, A non-amide solvent having a relatively high dielectric constant such as a nitro solvent such as nitroethane or an ester solvent such as γ-butyrolactone or cellosolve acetate can also be used. The solvent having a relatively high dielectric constant refers to a solvent having a dielectric constant of 5 or more, preferably 15 or more, measured at 20 ° C. or 25 ° C. The non-amide solvent is not limited to these. In addition, xylene, toluene, etc. at 20 ℃ or 2
A low dielectric constant solvent having a dielectric constant of less than 5 measured at 5 ° C. can also be used as a mixture with the high dielectric constant solvent. Also, a small amount of water, a metal salt such as lithium bromide, lithium chloride, or the like may be added to the above solvent. Needless to say, conventionally used amide solvents such as dimethylformamide, sulfur solvents such as dimethylsulfoxide and sulfolane, or tetramethylurea can also be used as the polymerization solvent of the present invention. The above-mentioned polymerization solvents may be used alone or as a mixture.

The reaction temperature is usually preferably 50 to 200 ° C., and the reaction is a catalyst for the reaction of isocyanate with an active hydrogen compound, for example, tertiary amines, alkali metal compounds, alkaline earth metal compounds, cobalt, titanium, It may be carried out in the presence of a metal such as tin or zinc or a semimetal compound. The reaction is usually carried out at normal pressure, but it may be carried out under pressure.

In obtaining the polyimide of the present invention, diphenyl ether-3,3'-is used as the acid component monomer.
4,4'-tetracarboxylic anhydride, benzophenone-
3,3′-4,4′-tetracarboxylic acid anhydride, biphenyl-3,3′-4,4′-tetracarboxylic acid anhydride,
Biphenyl-2,2'-3,3'-tetracarboxylic anhydride, diphenylsulfone-3,3'-4,4'-tetracarboxylic anhydride, diphenylsulfone-2,2'-
It is essential to use 3,3′-tetracarboxylic acid anhydride or a linear or branched C _1-4 alkylene glycol bis [anhydrotrimellitate] aromatic tetracarboxylic acid anhydride. These may be used alone or as a mixture of two or more.

As the acid component which may be copolymerized in addition to the above-mentioned aromatic tetracarboxylic acid anhydride, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, Aliphatic dicarboxylic acids such as sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, isophthalic acid, 5-te
rt-butyl-1,3-benzenedicarboxylic acid, terephthalic acid, diphenylmethane-4,4′-dicarboxylic acid,
Diphenylmethane-2,4'-dicarboxylic acid, diphenylmethane-3,4'-dicarboxylic acid, diphenylmethane-3,3'-dicarboxylic acid, 1,2-diphenylethane-4,4'-dicarboxylic acid, 1,2-diphenyl Ethane-2,4'-dicarboxylic acid, 1,2-diphenylethane-3,4'-dicarboxylic acid, 1,2-diphenylethane-3,3'-dicarboxylic acid, 2,2-bis (4-carboxyphenyl) ) Propane, 2- (2-carboxyphenyl) 2- (4-carboxyphenyl) propane, 2-
(3-Carboxyphenyl) 2- (4-carboxyphenyl) propane, 2,2-bis (3-carboxyphenyl) propane, diphenylether-4,4-dicarboxylic acid, diphenylether-2,4-dicarboxylic acid, diphenylether-3 , 4-dicarboxylic acid, diphenyl ether-3,3-dicarboxylic acid, diphenyl sulfide-4,4-dicarboxylic acid, diphenyl sulfide-
2,4-dicarboxylic acid, diphenyl sulfide-3,4
-Dicarboxylic acid, diphenyl sulfide-3,3-dicarboxylic acid, diphenyl sulfone-4,4-dicarboxylic acid, diphenyl sulfone-2,4-dicarboxylic acid, diphenyl sulfone-3,4-dicarboxylic acid, diphenyl sulfone-3,3 -Dicarboxylic acid, benzophenone-4,
4-dicarboxylic acid, benzophenone-2,4-dicarboxylic acid, benzophenone-3,4-dicarboxylic acid, benzophenone-3,3-dicarboxylic acid, 1,1,3-trimethyl-5-carboxy-3- (p-carboxy Aroma such as phenyl) indane, pyridine-2,6-dicarboxylic acid, bis [(4-carboxy) phthalimide] -4,4′-diphenyl ether, bis [(4-carboxy) phthalimide] -α, α′-methaxylene Group dicarboxylic acids, benzene-1,2,4-tricarboxylic acid, butane-
1,2,4-tricarboxylic acid, naphthalene-1,2,4
-Tricarboxylic acids and their anhydrides, butane-1,
2,3,4-tetracarboxylic acid, cyclobutane-1,
2,3,4-tetracarboxylic acid, benzene-1,2,
4,5-Tetracarboxylic acid (pyromet acid), benzene-1,2,3,4-tetracarboxylic acid, naphthalene-
2,3,6,7-tetracarboxylic acid, naphthalene-1,
2,4,5-tetracarboxylic acid, naphthalene-1,4
5,8-Tetracarboxylic acid, decahydronaphthalene-
1,4,5,8-Tetracarboxylic acid, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-
1,2,5,6-tetracarboxylic acid, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic acid, 2,
7-dichloronaphthalene-1,4,5,8-tetracarboxylic acid, 2,3,6,7-tetrachloronaphthalene-
1,4,5,8-tetracarboxylic acid, phenanthrene-
1,3,9,10-tetracarboxylic acid, perylene-3,
4,9,10-tetracarboxylic acid, bis (2,3-dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane, 1,1-bis (2,3-dicarboxyphenyl) ethane, 1,1-bis (3,4-dicarboxyphenyl) ethane, 2,2-bis (2,3-dicarboxyphenyl) propane, 2,3-bis (3,4-)
Dicarboxyphenyl) propane, cyclopentane-
1,2,3,4-tetracarboxylic acid, pyrrolidine-2,
3,4,5-tetracarboxylic acid, pyrazine-2,3
5,6-tetracarboxylic acid, thiophene-2,3,4
Examples thereof include 5-tetracarboxylic acid, 2,3,5-tricarboxycyclopentyl acetic acid, and dianhydrides thereof. These can be used alone or as a mixture of two or more kinds. The acid component that may be copolymerized is
It is used within the range in which the objective effects of the present invention can be achieved,
Usually, it is 60 mol% or less, preferably 30 mol% or less in the total acid components.

As the diamine component, the following general formula (X):

[0024]

[Chemical 19]

It is essential to use a diamine represented by the formula (wherein R ¹ and R ² are as defined above) or a diisocyanate corresponding thereto.

Further, for the purpose of imparting solubility and the like, 1,
4-bis (4-aminophenoxy) benzene, 1,3-
Bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 2,2-bis [4
-(4-aminophenoxy) phenyl] propane, 2,
2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (2-Aminophenoxy) phenyl] sulfone, 3,3-diaminodiphenylsulfone, 4,4-diaminophenylsulfone, isophoronediamine, 3,3′-diaminodiphenylpropane, 4,4′-diaminodiphenylpropane and like diamines, Alternatively, it is essential to polymerize the corresponding diisocyanate alone or as a mixture of two or more kinds.

Further, as the diamine component, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, m-phenylene, p-phenylenediamine, oxydianiline, methylenedianiline, hexafluoroisopropyl Redidianiline, 1,
4-naphthalenediamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine, 2,7-naphthalenediamine, 2,2'-bis (4-aminophenyl) propane, 2,2'-bis (4-amino) Phenyl) hexafluoropropane, 4,4'-diaminodiphenyl ether, 3,4'-diaminobiphenyl, 4,4'-diaminobenzophenone, hexamethylenediamine, tetramethylenediamine, 5-amino-1- (4'-aminophenyl ) -1,3,3'-Trimethylindane, 3,4 '
-Diaminodiphenyl ether, isopropylidenedianiline, 3,3'-diaminobenzophenone, 4,4 '
-Diaminocyclohexyl, o-tolidine, 2,4-tolylenediamine, 4,4 '-[1,3-phenylenebis (1-methylethylidene)] bisaniline, 4,4'-
[1,4-phenylenebis (1-methylethylidene)]
Bisaniline, 3,3 '-[1,3-phenylenebis (1-methylethylidene)] bisaniline, 4,4'-
Bis (4-aminophenoxy) biphenyl, 4,4'-
Diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfide, or 6-amino-1- (4 ′
-Aminophenyl) -1,3,3-trimethylindane or a diisocyanate corresponding thereto may be copolymerized. These can be polymerized alone or as a mixture of two or more kinds. The diamine or diisocyanate that may be copolymerized is used within a range that does not impair the properties of the polyimide of the present invention, but usually in all diamine (diisocyanate) components, 50 mol% or less,
It is preferably 30 mol% or less.

The polyimide of the present invention may be a block copolymer of the repeating unit (I) and the repeating unit (II) or may be a random copolymer.

The optimum value of the molecular weight of the polyimide depends on each composition and use, but it is 0.1 to 2.5 dl / g, preferably 0. 0, in the logarithmic viscosity value at 30 ° C. in N-methyl-2-pyrrolidone. It is in the range of 4-1.5 dl / g.

The molar ratio of the diamine of the formula (X) or its corresponding diisocyanate to the above-mentioned diamine to be copolymerized (a part of the Ar component) or its corresponding diisocyanate is about 90/10 to 30 although it depends on each composition.
Optimal values such as colorability and solubility are found in the range of / 70.

The polyimide of the present invention is not only soluble in ordinary amide solvents such as dimethylformamide, dimethylacetamide, diethylacetamide, N-methyl-2-pyrrolidone and hexamethylphosphoamide, which are solvents for polyimide. Dioxane, diglyme, tetrahydrofuran, and other ether-based organic solvents, toluene, xylene, and other hydrocarbon-based organic solvents, cyclohexanone, cyclopentanone, methyl ethyl ketone, methyl isobutyl ketone, and other ketone-based organics that could not be dissolved with conventional polyimide-based polymers It is also soluble in solvents and other non-amide polar solvents such as isophorone, acetonitrile and γ-butyrolactone. Among them, diglyme, tetrahydrofuran, cyclohexanone and γ-butyrolactone are preferably used from the viewpoint of solubility and toxicity.

When the polyimide of the present invention is used as a varnish, the above-mentioned amide-based solvent and non-amide-based solvent can be used. The ratio of the polyimide to the solvent is appropriately determined depending on the purpose of use, etc., but usually the solvent is 100 to 3,000 parts by weight, preferably 3 parts by weight with respect to 100 parts by weight of the polyimide.
0 to 1,000 parts by weight are used.

The polyimide of the present invention and a varnish dissolved in a solvent are prepared by solution casting, dry spinning, wet spinning,
Molding can be performed by a conventionally known method such as gel spinning, melt spinning, melt molding, injection molding and the like. Especially solution casting,
In the case of solution molding such as dry spinning, since a general-purpose solvent with a low boiling point and low hygroscopicity can be used, it is easy to handle, and the physical properties of the obtained molded product are more transparent than those molded from conventional amide solvents. , Mechanical properties are remarkably excellent.

The form of the molded product is not particularly limited, but it may be a molded product such as a film, a fiber, a hollow fiber, a pipe or a bottle. The application is not particularly limited, but may be for automobiles, chemical plants, aviation / space, mechanical / electrical / electronic parts,
Can be used as a material.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0036]

【Example】

Example 1 The following polymerization components were charged in a reaction vessel and heated to 180 ° C. in about 30 minutes while stirring. After stirring at 180 ° C. for about 5 hours, the reaction was stopped. Polymerization component 4,4'-benzophenone tetracarboxylic acid anhydride 0.3 mol 4,4'-diphenylsulfone tetracarboxylic acid anhydride 0.7 mol Isophorone diisocyanate 0.3 mol 4,4'-dicyclohexylmethane diisocyanate 0.7 Molar γ-butyrolactone 0.2 liters Diglyme 0.8 liters The above polyimide solution was cast-coated on a 100 μm-thick releasable polyester film so that the thickness after drying would be 30 μm, and at 100 ° C. for 5 minutes. After drying at 150 ° C. for 30 minutes, the release film was peeled off. Then, in order to completely remove the solvent, the mixture was heated under reduced pressure at 200 ° C. for about 3 hours. The various physical properties of the polyimide film thus obtained are shown below. The polyimide polymerization solution was diluted with N-methyl-2-pyrrolidone and then reprecipitated in methanol to obtain a polyimide polymer powder. The solubility of the powder thus obtained was investigated. The measuring method is shown below. Tg (° C.): According to TMA tensile measurement method. Load: 1 g, sample size, 5 × 20 mm Measured at a temperature rise temperature of 10 ° C./min Light transmittance: A film having a thickness of 25 μm was used, and a wavelength of 50 was used.
Measured at 0 nm Coefficient of thermal expansion: Same as Tg. Value in the range of 100 to 200 ° C. Solubility: Polymer powder (diameter: 2 to 3 μm) was mixed with a solvent to a concentration of 20% by weight, stirred at room temperature, and visually observed. ○: dissolved △: swelled ×: insoluble

Examples 2 to 6 Polyimides were produced in the same procedure as in Example 1 except that the isophorone diisocyanate component was changed to the monomer component shown in Table 1. Each physical property was measured in the same manner as in Example 1. The results are shown in Table 1.

[0038]

[Table 1]

[0039]

INDUSTRIAL APPLICABILITY The polyimide of the present invention is not only heat-resistant, but also cannot be used conventionally, cyclohexanone,
It is also soluble in general-purpose solvents with low hygroscopicity and low boiling points, such as dioxane, toluene, xylene, tetrahydrofuran, and diglyme. Therefore, it has excellent solution formability, its film,
Molded articles such as fibers show extremely high light transmittance and are substantially colorless and transparent.

Front page continued (72) Inventor Hideo Nishino 1-1-1 Katata, Otsu City, Shiga Prefecture Inside Toyobo Co., Ltd.

Claims (6)

[Claims] 1. The following general formula (I):[In the formula, R⁰Is -O-, -SO₂-, -CO-, -CO
-OR^Four-O-CO- (In the formula, R^FourHas 1 to 4 carbon atoms
Alkylene) or a direct bond to R¹, R ²Is the same
One or different, each hydrogen or
Representing an alkyl group having 1 to 4 carbon atoms]
Units and the following general formula (II):[In the formula, R⁰'Is -O-, -SO₂-, -CO-, -CO
-OR^Four'-O-CO- (in the formula, R^Four'Has 1 to 4 carbon atoms
An alkylene group) or a direct bond, Ar is a divalent
A copolymer having a repeating unit represented by [showing an organic group]
Polyimide. 2. Ar is of formula (III): Formula (IV): Formula (V): Formula (VI): Formula (VII): Formula (VIII): Formula (XI): The polyimide according to claim 1, which is at least one organic group selected from the group consisting of: 3. The method for producing a polyimide according to claim 1, wherein the tetracarboxylic acid anhydride and the diisocyanate are reacted in a polar solvent having a dielectric constant of 5 or more measured at 20 ° C. or 25 ° C. 4. The method according to claim 3, wherein the polar solvent is a non-amide polar solvent. 5. A polyimide varnish containing the polyimide according to claim 1 or 2 in a polar solvent. 6. The polyimide varnish according to claim 5, wherein the polar solvent is a non-amide polar solvent.