JPH0519576B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a strong heat-resistant resin having a hetero imide ring and a furan ring in the polymer main chain and having excellent light transmittance. be. The purpose is that the cured resin imidized by the ring-closing process has excellent heat resistance, abrasion resistance, chemical resistance, electrical insulation, film-forming properties, flexibility, mechanical properties, etc. as a polyimide resin. materials for electronic devices,
Electrical insulation materials, coatings, adhesives, paints, molded products,
The object of the present invention is to provide a heat-resistant resin useful as a laminate, fiber, or film material, and in particular, to provide a heat-resistant resin useful as an alignment film for a liquid crystal display element for electronic devices.

[Prior art]

Conventionally, heterocycles such as imide, imidazole, thiazole, oxazole,
It is well known that compounds containing oxadiazole, triazole, quinoxaline, thiadiazole, oxazinone, quinazoline, imidazopyrrolone, isoindolo, quinazolone, etc. have excellent heat resistance. However, these known polymers have rigid polymer main chains, and when formed into films, films, or coatings, they have poor flexibility, flexibility, elongation, or adhesiveness. Therefore, when used as a compounded film for liquid crystal, for example, it cannot withstand rubbing work and cannot sufficiently contain liquid crystal, making it unable to function as a display element. Furthermore, when these polymers are heated during curing, they become significantly colored, becoming brown or blackish brown. Therefore, when used as an alignment film for a liquid crystal, for example, the liquid crystal display element becomes brownish, the visual field becomes dark, the contrast decreases, and it no longer functions as a display element. From this point of view, various studies have been made in the past in order to achieve a balance between heat resistance, flexibility, light colorability, and adhesiveness, but it has generally been the case that when one is good, the other is bad.

[Purpose of the invention]

As a result of studies aimed at overcoming such drawbacks, the present invention uses 2,8-diaminodiphenylene oxide, 2,4-diaminotoluene, and 1,4-bis(3-aminopropyldimethyl) as diamine components. By using silyl)benzene and 3,3',4,4'-benzophenone tetracarboxylic dianhydride as essential components, heat resistance and flexibility are achieved. The present invention was completed based on the discovery that a heat-resistant resin with a good balance of light color and adhesiveness can be obtained.

[Structure of the invention]

The present invention uses 2,8-diaminodiphenylene oxide, 2,4-diaminotoluene, and 1,4-diaminodiphenylene oxide as diamine components when reacting diamine and tetracarboxylic dianhydride to form an imide ring.
-bis(3-aminopropyldimethylsilyl)benzene and 3,3',4,4'-benzophenonetetracarboxylic dianhydride as an essential component. This is a unique method for producing heat-resistant resin.

Among the diamines used in the present invention, the essential components are 2,8-diaminodiphenylene oxide and 2,8-diaminodiphenylene oxide.
4-diaminotoluene and 1,4-bis(3-aminopropyldimethylsilyl)benzene.
One way to make 2,8-diaminodiphenylon oxide is shown in the following reaction formula.

Reference: University of Fukui Faculty of Engineering Research Report 16(2)238('
68) Of course, diamines other than those mentioned above can also be used. For example, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane, benzidine, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl methane, 4'-diaminodiphenyl sulfone, 3,
3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 2,6-diaminopyridine, bis(4-aminophenyl)phosphine oxide, bis(4-aminophenyl)-N-methylamine, 1,5 -diaminonaphthalene, 3,
3'-dimethyl-4,4'-diaminobiphenyl,
3,3'-dimethoxybenzidine, 2,4-bis(β-amino-t-butyl)toluene, bis(p
-β-amino-t-butylphenyl) ether,
p-bis(2methyl-4-aminopentyl)benzene, p-bis(1,1-dimethyl-5-aminopentyl)benzene, m-xylylenediamine,
p-xylylenediamine, bis(p-aminocyclohexyl)methane, ethylenediamine, propylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, 3
-Methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11-diaminodecane, 1,2-bis(3-aminopropoxy)
Ethane, 2,2-dimethylpropylene diamine,
3-methoxyhexamethylene diamine, 2,5-
Dimethylhexamethylenediamine, 2,5-dimethylnonamethylenediamine, 1,4-diaminocyclohexane, 2,12-diaminooctadecane,
2,5-diamino-1,3,4-oxadiazole and the like.

Furthermore, among the tetracarboxylic dianhydrides used in the present invention, an essential component is 3,3',4,4'-benzophenonetetracarboxylic dianhydride. However, other tetracarboxylic dianhydrides can of course also be used. For example, pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-diphenyltetracarboxylic dianhydride, 1,2,5,6 -naphthalenetetracarboxylic dianhydride, 2,2',
3,3'-diphenyltetracarboxylic dianhydride,
2,2-bis(3,4-dicarboxydiphenyl)propane dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis(3,4-dicarboxydiphenyl)ether dianhydride, Ethylenetetracarboxylic dianhydride, naphthalene
1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,
6,7-hexahydronaphthalene-1,2,5,
6-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,
4,5,8-tetracarboxylic dianhydride, 2,
3,4,7-tetrachloronaphthalene-1,4,
5,8-tetracarboxylic dianhydride, phenanthrene-1,2,9,10-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrrolidine-2, 3,4,5
-tetracarboxylic dianhydride, pyrazine 2,3,
5,6-tetracarboxylic dianhydride, 2,2-bis(2,5-dicarboxyphenyl)propane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1 ,1-bis(3,4
-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, benzene-1,2,3,4- Tetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, thiophene-2,
3,4,5-tetracarboxylic dianhydride and the like.

The amount of 2,8-diaminodiphenylene oxide, which is an essential component, is preferably 0.5 to 50 mol%.
0.5 mol% is preferred. If it is less than 0.5 mol%, the effect of improving heat resistance strength is small, and if it is more than 50 mol%, the molecular weight does not increase, probably due to steric hindrance of the molecular structure.
Also, 2,4-diaminotoluene and 3,3', 4,4'-
The amount of benzophenone tetracarboxylic dianhydride used is preferably 20 mol % or more, and if it is less than this, the effect of improving coloration is small. Also, 1,4-
The amount of bis(3-aminopropyldimethylsilyl)benzene used is preferably 0.1 to 30 mol%. 0.1
If the amount is less than mol %, the effect of colorless removal and improvement of adhesiveness will be small, and if it is more than 30 mol %, the cured product will be brittle.

In the present invention, the reaction between diamines and tetracarboxylic dianhydrides is preferably carried out in equimolar amounts as much as possible, which increases the degree of polymerization. If the amount of either raw material increases by 5% or more, the degree of polymerization will drop significantly and a low molecular weight product with poor film-forming properties will be produced, so care must be taken. Usually, one raw material is
Using 3% more is often done to improve workability and processability.

The solvent of the reaction system in the present invention is an organic polar solvent whose functional group has a dipole moment that does not react with the tetracarboxylic dianhydride or diamines.

In addition to being inert to the system and solvent to the product, the organic polar solvent must be solvent to at least one, preferably both, of the reaction components.

Typical solvents of this type are N,N-
Dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, N,N
-diethylacetamide, N,N-dimethylmethoxyacetamide, dimethylsulfoxide, hexamethylphosphoamide, N-methyl-2-pyrrolidone, pyridine, dimethylsulfone, tetramethylenesulfone, dimethyltetramethylenesulfone, etc. These solvents can be used alone or used in combination.

Other solvents that can be used in combination include benzene, benzonitrile, dioxane,
Nonsolvents such as butyrolactone, xylene, toluene, and cyclohexane are used as dispersion media for raw materials, reaction regulators, solvent volatilization regulators from products, film smoothing agents, and the like.

It is generally preferred that the present invention be carried out under anhydrous conditions.

This is because the tetracarboxylic dianhydride is ring-opened by water, becomes inactivated, and there is a risk of stopping the reaction.

Therefore, it is necessary to remove both the moisture in the raw materials and the moisture in the solvent.

However, in order to adjust the progress of the reaction and control the degree of resin polymerization, water is sometimes intentionally added.

Further, the present invention is preferably carried out in an inert gas atmosphere.

This is to prevent oxidation of diamines.

Dry nitrogen gas is generally used as the inert gas.

The reaction in the present invention can be carried out in various ways as follows.

(1) Diamines and tetracarboxylic dianhydride are mixed in advance, and the mixture is added little by little to an organic solvent while stirring. This method is relatively advantageous in exothermic reactions such as those for polyimide resins.

(2) Conversely, there is also a method of adding a solvent to a mixture of diamines and tetracarboxylic dianhydride while stirring.

(3) A commonly used method is to dissolve only diamines in a solvent, and then add tetracarboxylic dianhydride to this in a proportion that allows the reaction rate to be controlled.

(4) It is also possible to dissolve diamines and tetracarboxylic dianhydride separately in a solvent and then slowly add the two solutions in a reactor.

(5) Furthermore, it is also possible to prepare in advance a polyamic acid product containing an excess of diamines and a polyamic acid product containing an excess of tetracarboxylic dianhydride, and then further react them in a reactor.

(6) Among the diamines, there is also a method in which a part of the diamine compound and tetracarboxylic dianhydride are first reacted and then the remaining diamine compound is reacted, or the reverse method is also available.

(7) In addition, some diamine compounds and tetracarboxylic dianhydride are reacted together, and the remaining diamine compound and tetracarboxylic dianhydride are reacted before use. There is also a method of mixing.

The reaction temperature is preferably 0 to 100°C. This is because if the temperature is below 0°C, the reaction rate is slow, and if it is above 100°C, the produced polyamic acid gradually starts the ring-closing reaction.

Usually, the reaction is carried out at around 20°C. The degree of polymerization of polyamic acid can be controlled in a planned manner.

In order to control the degree of polymerization, it is also possible to end-block with phthalic anhydride or aniline, or add water to ring-open one of the acid anhydride groups to inactivate it.

When used, the polyamic acid product produced by the method of the present invention has the adhesion and adhesion properties of various silane coupling agents, borane coupling agents, titanate coupling agents, aluminum coupling agents, and other chelate coupling agents. Improvers, various solvents, and flow agents may be added, and in addition to these, ordinary acid curing agents, amine curing agents,
Small amounts of polyamide curing agents and curing accelerators such as imidazole and tertiary amines may be added, as well as flexibility agents and viscosity modifiers such as rubber, polysulfide, polyester, and low-molecular epoxy, talc, clay, mica, Fillers such as feldspar powder, quartz powder, and magnesium oxide; colorants such as carbon black and phthalocyanine blue; flame retardants such as tetrabromophenylmethane and tributyl phosphate;
Small amounts of flame retardant aids such as antimony trioxide, barium metaborate, etc. may also be added, and their addition opens up many applications.

The polyamic acid product produced by the method of the present invention is imidized and cured by heating or by using a dehydrating agent.

The heating temperature for the former thermal dehydration treatment is usually 50°C or higher, preferably 150°C or higher, preferably 200 to 400°C. Although air may be used as the atmosphere in this case, it is often preferable to use non-oxidizing conditions such as reduced pressure or inert gas. The latter dehydrating agents include acetic anhydride, propionic anhydride,
Carboxylic anhydrides such as benzoic anhydride are often used, and these are particularly effective when used in the coexistence of basic substances such as pyridine and quinoline. Solid dehydrating agents include zeolite-based molecular sieves, silica gel, and activated alumina, which are more effective when used after being slightly heated.

〔Effect of the invention〕

According to the method of the invention, 2,8-diaminodiphenylene oxide, 2,4-diaminotoluene, 1,4-bis(3-aminopropyldimethylsilyl)benzene, 3,3',4,4' -A polymer containing benzophenone tetracarboxylic dianhydride as an essential component is an excellent heat-resistant resin that has a good balance of heat resistance, flexibility, light color, and adhesiveness.

That is, the polymer synthesized by the method of the present invention is
By using 2,8-diaminodiphenylene oxide, it has a large number of aromatic rings and heterocycles in its molecular structure, and has excellent heat resistance. In addition, the main chain has a helical shape, which is thought to provide excellent flexibility with a spring-like effect. Furthermore, 2,4-diaminotoluene and 3,3′,
A heat-resistant resin with little coloring can be obtained, probably because the main chain cannot form a conjugated structure due to the introduction of 4,4'-benzophenonetetracarboxylic dianhydride. Furthermore, by introducing 1,4-bis(3-aminopropyldimethylsilyl)benzene, the imide group content is diluted, resulting in a heat-resistant resin with less coloring and good adhesiveness.

Specifically, the uses of the present invention are as follows:
First, it is used as a coating film to protect the surfaces of various electronic equipment, and as a heat-resistant insulating film for multilayer wiring on top of it.

For example, semiconductors, transistors, linear
IC, hybrid IC, light emitting diode, LSI, super
This is a wiring structure for electronic circuits such as LSI.

Next, since the heat-resistant resin of the present invention is light-colored, it can also be used as an alignment film for liquid crystal display devices.

That is, the polymer solution of the present invention is applied to a glass substrate or a plastic film substrate on which a transparent conductive film containing tin oxide or indium oxide as a main component is formed by a dipping method, a spin coating method, a spray method, a printing method, etc. After heat curing, rubbing treatment is performed.
The rubbing method can be performed using gauze, buffing, or other conventional means. Liquid crystals that can be used in combination with the alignment film of the present invention include nemate liquid crystals such as Schiff base type liquid crystals, phenylcyclohexane type liquid crystals, azoxy type liquid crystals, azo type liquid crystals, biphenyl type liquid crystals, ester type liquid crystals, and phenyl-pyrimidine type liquid crystals; An optically active substance is added to the above nemate liquid crystal.
Examples include cholesteric liquid crystals containing optically active compounds such as cholesterol compounds, biphenyl derivatives having optically active substituents, and phenylbenzoate.

In addition, as a coating varnish for high temperatures,
It is used as a coating for electric wires, magnet wires, dip coatings for various electrical parts, protective coatings for metal parts, etc., and also as an impregnating varnish.
Used for impregnating glass cloth, fused silica cloth, graphite fibers and boron fibers in radar domes, printed circuit boards, radioactive waste containers, turbine blades, spacecraft and other structures requiring high temperature performance and excellent electrical properties. It is used in parts, and as an interior material for waveguides in computers, atomic equipment, and X-ray equipment to prevent microwaves and radiation.

It is also used as a molding material to create self-lubricating sliding surfaces by adding graphite powder, graphite fiber, molybdenum disulfide, and polytetrafluoroethylene, and is used for piston rings, valve seats, bearings, seals, etc. It is also used to make jet engine parts, high-strength structural molded parts, etc. with the addition of glass fiber, graphite fiber, or boron fiber.

It is also used as a high-temperature adhesive for bonding electrical circuit parts and structural parts of spacecraft.

〔Example〕

The present invention will be explained below with reference to Examples.

Example 1 A four-necked separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet was
39.646 g (20 mol%) of purified anhydrous 2,8-diaminodiphenylene oxide, 85.519 g (70 mol%) of 2,4-diaminotoluene, and 1,4-
Take 30.862 g (10 mol%) of bis(3-aminopropyldimethylsilyl)benzene and add a mixed solvent of 95% by weight of anhydrous N-methyl-2-pyrrolidone and 5% by weight of xylene to it to reduce the solid content of all raw materials. An amount sufficient to make the proportion 15% by weight was added and dissolved.
Dry nitrogen gas was kept flowing throughout the entire process from the preparatory stage of the reaction to the removal of the product.

Then, 322.230 g of purified anhydrous 3,3',4,4'-benzophenonetetracarboxylic dianhydride
(100 mol %) was added little by little with stirring, but since it was an exothermic reaction, cold water at about 15°C was circulated in an external water tank to cool it. After the addition, the internal temperature was set at 20°C and stirred for 10 hours to complete the reaction.

The obtained product was a transparent yellow and extremely viscous polyamic acid solution, and the intrinsic viscosity of the 0.5% by weight solution of N-methyl-2-pyrrolidone was 0.64 (30 DEG C.).

Next, a 5% by weight solution of this polyamic acid in N-dimethylacetamide was dropped onto a glass plate and spun at 400 rpm/min for 10 seconds and then 2000 rpm/min for 20 seconds using a spinner to spread it evenly. did. This was done at 80℃, 150℃, and 250℃ under reduced pressure.
℃ and 350℃ for 30 minutes each to cause dehydration and ring closure to obtain a pale yellow, transparent, and tough polyimide resin film with a thickness of 1 μm. Looking at the infrared absorption spectrum of this film, strong absorption based on the imide ring was observed at 1780 cm ^-1 and 730 cm ^-1 and strong absorption based on the furan ring was observed at 1200 cm ^-1 .

This film has extremely excellent heat resistance, and the starting temperature of thermal decomposition in air was 500°C at a heating rate of 5°C/min as measured by a differential thermal balance analyzer.
The film also had high strength, with an excellent tensile strength of 13 kg/mm ² at 200°C. Furthermore, the film had excellent light color properties and a light transmittance of 92% at 400 nm. Furthermore, in a cellophane tape peeling test (JIS-D-2020) on a glass plate, the peeling rate was 0%, indicating excellent adhesion.

Example 2 Using the same apparatus and method as in Example 1, 19.823 g (10 mol%) of 2,8-diaminodiphenylene oxide, 73.302 g (60 mol%) of 2,4-diaminotoluene, and 4,4'- Diaminodiphenyl ether
40.048g (20mol%) and 30.862g of 1,4-bis(3-aminopropyldimethylsilyl)benzene
(10 mol%), 161.115 g (50 mol%) of 3,3',4,4'-benzophenonetetracarboxylic dianhydride and 109.060 g (50 mol%) of pyromellitic dianhydride.
mol%).

The obtained product was a transparent yellow and extremely viscous polyamic acid solution with an inherent viscosity of 0.68. The obtained film is pale yellow and transparent and has excellent toughness, with a thermal decomposition initiation temperature of 500℃, hot tensile strength of 13Kg/mm ² , light transmittance of 90%, and cellophane tape peeling rate of 0%. It was hot.

Comparative Example 1 Using the same apparatus and method as in Example 1, 122.170 g of 2,4-diaminotoluene ((100 mol%)) and 3,
322.230 g (100 mol %) of 3',4,4'-benzophenonetetracarboxylic dianhydride was reacted.

The obtained film had excellent light color properties, but the temperature at which thermal decomposition started was only 320°C.
The hot tensile strength was 5 Kg/mm ² , and the cellophane tape peeling rate was poor at 95%, so it could not withstand rubbing work at all.

Comparative Example 2 Using the same equipment and method as in Example 1, 97.736 g (80 mol%) of 2,4-diaminotoluene and 1,4-
61.724 g (20 mol%) of bis(3-aminopropyldimethylsilyl)benzene and 3,3′,4,4′-
Benzophenonetetracarboxylic dianhydride
322.230g (100 mol%) was reacted.

The obtained film had excellent light color properties and good adhesion, but its thermal decomposition initiation temperature was only 320°C and its hot tensile strength was only 5 kg/mm ² .

Comparative Example 3 Using the same apparatus and method as in Example 1, 19.823 g (10 mol%) of 2,8-diaminodiphenylene oxide and 109.953 g (90 mol%) of 2,4'-diaminotoluene were prepared.
(mol %) and 322.230 g (100 mol %) of 3,3',4,4'-benzophenonetetracarboxylic dianhydride were reacted. The obtained film had excellent light color property, high thermal decomposition initiation temperature, and strong hot tensile strength, but the cellophane tape peeling rate was poor at 100%.

Claims (1)

[Claims] 1. In a method for producing a polyimide resin comprising a tetracarboxylic dianhydride and a diamine, as the tetracarboxylic dianhydride component, 3,3',4,
4′-benzophenonetetracarboxylic dianhydride
Contains 20 mol% or more, as a diamine component, 2,
8-diaminodiphenylene oxide, 2,4-
Diaminotoluene and 1,4-bis(3-aminopropyldimethylsilyl)benzene each from 0.5 to
Contains 50 mol%, 20 mol% or more, 0.1 to 30 mol%,
A method for producing a heat-resistant resin, characterized in that the molar ratio of tetracarboxylic dianhydride and diamine is 100:95 to 105, and the reaction is carried out at a temperature of 0 to 100°C.