JP2011016969A - Liquid polyimide composition and polyimide film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid polyimide composition which can be suitably used for preparing a polyimide film that is excellent in heat resistance in a process wherein the temperature is low and 250°C or less.SOLUTION: The liquid polyimide composition comprises a polyimide having a substituent group represented by formula (1) and an organic solvent, wherein Ris hydrogen or methyl, Rand Rare independently an alkyl group having a carbon number of 1-6, and * indicates that the bond attached with the symbol should bind to another polyimide-constitutive unit.

Description

  The present invention relates to a liquid polyimide composition. More specifically, the present invention relates to a liquid polyimide composition containing a solvent-soluble polyimide and an organic solvent as essential components.

  In addition to high heat resistance due to high glass transition temperature, polyimide has excellent mechanical, electrical, and chemical properties, so it can be used for protection of various substrates, insulation, and adhesion in the field of electrical and electronic materials. It is used as an indispensable material as a substrate for flexible printed wiring circuits, a substrate for tape automation bonding, a protective film for semiconductor elements, an interlayer insulating film for integrated circuits, and the like.

  Since many polyimide resins are insoluble and infusible, the polyimide film is usually prepared by applying a polyamic acid amide solvent solution, which is a polyimide precursor, onto the substrate, followed by thermal imidization. Is used. In this thermal imidization process, high-temperature heating at 300 ° C. or higher is required for dehydration ring-closing reaction (imidization), de-solubilization, and removal of generated water. It has been pointed out that the reliability has decreased. In addition, the polyamic acid solution has a significant problem in storage stability, such as requiring refrigerated storage, because hydrolysis of the polyamic acid is accelerated by moisture absorption of the amide polar solvent as the main solvent.

  From the above problems, the use of a solvent-soluble polyimide has been proposed as a liquid polyimide material that replaces polyamic acid. Since the solvent-soluble polyimide is soluble in a solvent in an imidized state, a liquid polyimide material having excellent storage stability can be provided. Moreover, since the imidation reaction after application | coating is unnecessary at the time of use, a polyimide film can be produced with a low temperature process of 250 degrees C or less.

As the solvent-soluble polyimide, for example, an alicyclic polyimide in which a bulky alicyclic structure is introduced on the main chain to reduce the cohesive force (for example, see Patent Document 1), or a soluble block is introduced into the main chain. Thus, a block copolymerized polyimide (for example, see Patent Document 2) having an increased interaction with a solvent has been proposed.
However, these solvent-soluble polyimides have a problem that the heat resistance and mechanical properties of the coating film are inferior to those of polyimides obtained by thermal imidization of conventional polyamic acids.

JP 2008-163089 A JP 2008-231420 A

  An object of this invention is to provide the liquid polyimide composition which can produce the polyimide film excellent in heat resistance by the low temperature process of 250 degrees C or less.

［式中、Ｒ¹は水素原子又はメチル基、Ｒ²及びＲ³はそれぞれ独立に炭素数１〜６のアルキル基、＊はそれが付された結合が他のポリイミド構成単位に結合することを表す。］ The inventor of the present invention has arrived at the present invention as a result of intensive studies to achieve the above object. That is, the present invention is a liquid polyimide composition containing a polyimide having a substituent represented by the general formula (1) and an organic solvent, and a polyimide film obtained by heat treatment after applying the liquid polyimide composition. .

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are each independently an alkyl group having 1 to 6 carbon atoms, and * indicates that the bond attached thereto is bonded to another polyimide constituent unit. To express. ]

  By using the liquid polyimide composition of the present invention, a polyimide film having excellent heat resistance can be easily formed.

  The liquid polyimide composition of the present invention comprises a polyimide having a substituent represented by the general formula (1) and an organic solvent as essential components. Since the substituent represented by the general formula (1) has a bulky ester structure, the polyimide is soluble in a solvent, and the ester bond is dissociated in the heat treatment step of the coating film. Sex can be imparted.

In general formula (1), R ¹ is a hydrogen atom or a methyl group. When R ¹ is a hydrocarbon group having 2 or more carbon atoms, the solvent resistance of the coating film may be insufficient. R ² and R ³ are each independently an alkyl group having 1 to 6 carbon atoms, and preferably an alkyl group having 2 to 6 carbon atoms from the viewpoint of solvent solubility. If the alkyl group has 7 or more carbon atoms, synthesis may be difficult. Moreover, solvent solubility may become inadequate when it is an unsaturated hydrocarbon group.

  The polyimide in the present invention can be obtained, for example, by reacting a diamine having a substituent represented by the general formula (1) with tetracarboxylic dianhydride. In addition, the diamine which does not have a substituent shown by General formula (1) can be used together as a diamine component.

  Examples of the diamine having no substituent represented by the general formula (1) include aromatic diamines having 6 to 20 carbon atoms (m-phenylenediamine, p-phenylenediamine, 4,4′-diaminobiphenyl, 2,2′- Dimethyl-4,4′-diaminobiphenyl, 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 4,4 ′ -Diaminodiphenylmethane, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylsulfone, etc.) and alicyclic diamines having 6 to 20 carbon atoms (1,4-diaminocyclohexane, isophorone diamine, 4,4'-diamino) Dicyclohexyl ether, 4,4′-diaminodicyclohexylmethane and 2,5-bis (amino Methyl) bicyclo [2.2.1] heptane and the like). These diamines may be used alone or in combination of two or more.

  Among the diamines having no substituent represented by the general formula (1), aromatic diamines having 6 to 20 carbon atoms are preferable from the viewpoint of heat resistance, and more preferable are p-phenylenediamine and 4,4′-. Diaminobiphenyl and 4,4′-diaminodiphenyl ether.

  As the diamine having the substituent represented by the general formula (1), the substituent represented by the general formula (1) is introduced into the diamine having 6 to 20 carbon atoms not having the substituent represented by the general formula (1). Examples thereof include diamines having 12 to 60 carbon atoms.

  The method for introducing the substituent represented by the general formula (1) into the diamine is not particularly limited, and an organic synthesis method suitable for the structure of the diamine can be appropriately selected. For example, when the diamine is an aromatic diamine, a method of reducing the nitro group after modifying the carboxyl group of the dinitrobenzoic acid derivative by functional group conversion to convert to a substituent represented by the general formula (1), aromatic dinitro compound And a method of reducing the nitro group after introducing an acyl group or formyl group into the substituent represented by the general formula (1) by functional group conversion.

  Among the diamines having a substituent represented by the general formula (1), the diamine represented by the general formula (2) is preferable from the viewpoint of solvent solubility and heat resistance.

R ¹ in the general formula (2) is hydrogen or a methyl group. When R ¹ is a hydrocarbon group having 2 or more carbon atoms, the solvent resistance of the coating film may be insufficient. R ² and R ³ are each independently an alkyl group having 1 to 6 carbon atoms, and preferably an alkyl group having 2 to 6 carbon atoms from the viewpoint of solvent solubility. If the alkyl group has 7 or more carbon atoms, synthesis may be difficult. Moreover, solvent solubility may become inadequate when it is an unsaturated hydrocarbon group.
The diamine having a substituent represented by the general formula (1) may be used alone or in combination of two or more.

  The content of the substituent represented by the general formula (1) is 20 to 70% by weight based on the weight of the polyimide from the viewpoint of sufficient solubility and sufficient strength for the polyimide film. Preferably, it is 30 to 70% by weight.

  As tetracarboxylic dianhydride, what is used for normal polyimide synthesis can be used, and as a specific example, C10-20 aromatic tetracarboxylic dianhydride (pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenyl ether tetracarboxylic acid Dianhydrides, 4,4′-hexafluoroisopropylidenediphthalic anhydride and 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride) and alicyclic tetras having 8 to 20 carbon atoms Carboxylic dianhydrides (1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexyltetracarboxylic dianhydride and 3 ′, 4,4′-bisic Rohexyltetracarboxylic dianhydride and the like). These tetracarboxylic dianhydrides may be used alone or in combination of two or more.

  Among tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides having 10 to 20 carbon atoms are preferable from the viewpoint of heat resistance, and more preferable are pyromellitic dianhydrides, 3,3 ′, 4. , 4′-biphenyltetracarboxylic dianhydride and 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride.

Examples of the organic solvent in the present invention include amide solvents (N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, etc.), lactone solvents (γ-butyllactone, γ-valerolactone, etc.), ketones. Solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ester solvents (ethyl acetate, butyl acetate, amyl acetate, etc.), chlorinated solvents (trichloroethane, dichloroethylene, etc.) and ether solvents tetrahydrofuran, 1,4-dioxane 1,3-dioxolane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol monoethyl ether acetate, etc.).
Moreover, when obtaining a coating film or a film-form polyimide molded object from the liquid polyimide composition of this invention, a part of said solvent can be replaced with a highly volatile solvent in order to perform a drying process efficiently. Examples of the highly volatile solvent include aromatic hydrocarbons such as toluene and xylene, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane. When using these highly volatile solvents, the amount used is appropriately selected within a range in which polyimide can be dissolved.
Among these solvents, an amide solvent having 3 to 10 carbon atoms, a lactone solvent having 3 to 10 carbon atoms, and an ether solvent having 3 to 10 carbon atoms are preferable from the viewpoint of solubility and viscosity stability.
An organic solvent may be used independently and may use 2 or more types together.

  As a method for producing polyimide, a known method can be used. As the imidization method, for example, (i) a method of imidation while removing generated water out of the system under high temperature heating, and (ii) imidization at a relatively low temperature using an imidization accelerator in a solvent. Methods and the like.

  Of the above polyimide production methods, production method (ii) is preferred from the viewpoint of the thermal stability of the substituent represented by formula (1). As a preferable form of the production method (ii), for example, after the production of polyamic acid which is a polyimide precursor, pyridine and acetic anhydride are added as imidization accelerators, and imidization is performed at a temperature of 40 to 120 ° C. .

The charging molar ratio of diamine and tetracarboxylic dianhydride can be appropriately selected according to the molecular weight of the desired polyimide. The diamine and the tetracarboxylic acid anhydride are preferably reacted at a charge molar ratio of 1: 0.85 to 0.85: 1, more preferably 1: 0.90 to 0.90: 1, particularly preferably 1: 0.95-0.95-1. If either one is used in excess of the charged molar ratio, the molecular weight of the resulting polyimide will be low, and the film formability and the mechanical strength of the film may be insufficient.
Moreover, content of the substituent shown by General formula (1) in a polyimide can be adjusted by adjusting suitably the quantity of the diamine which has a substituent shown by General formula (1) in diamine.

  Examples of the solvent used for the reaction include the organic solvents described above, and the amount used thereof may be an amount that can dissolve the generated polyimide, but the film forming property and mechanical strength of the generated polyimide are sufficient, And from the viewpoint of suppressing gelation during the reaction, it is preferable to adjust so that the weight concentration of the total amount of diamine and tetracarboxylic dianhydride is 5 to 50% by weight, more preferably 10 to 40% by weight.

  There is no restriction | limiting in particular as an imidation promoter, The compound used normally, for example, combined use of a basic substance and a dehydration condensing agent, is mentioned.

  As the basic substance, amines such as pyridine, 4-dimethylaminopyridine, triethylamine and tributylamine, and inorganic bases such as potassium carbonate and sodium hydroxide can be used. Of these, pyridine is preferably used because it can be obtained at a low cost and has excellent solubility. As for the usage-amount of a basic substance, a minimum is 1.0 time normally with respect to the number of moles of the amic acid group contained in a polyimide precursor, Preferably it is 2.0 times. The upper limit is not particularly limited, but is usually 50 mole times, preferably 30 mole times. If there is too little basic substance, the progress of the reaction will be slow, and if it is too much, it will be difficult to remove.

  Examples of the dehydrating condensing agent include acid anhydrides such as acetic anhydride and propionic anhydride, N, N-dicyclohexylcarbodiimide, and the like. The lower limit of the amount used is usually 1.0 times, preferably 2.0 times the number of moles of amic acid groups contained in the polyimide precursor. The upper limit is not particularly limited, but is usually 50 mole times, preferably 30 mole times. If the amount of the dehydrating condensing agent is too small, the progress of the reaction is slow, and if it is too large, the removal becomes difficult.

  Although the reaction temperature depends on the type and concentration of the raw material used, the lower limit is usually −20 ° C., preferably 0 ° C. If the reaction temperature is too low, the reaction rate may decrease or the polymer may precipitate. The upper limit of the reaction temperature is usually 150 ° C., preferably 120 ° C., from the viewpoint of the thermal stability of the substituent represented by the general formula (1).

  Although reaction time is based also on reaction temperature, 0.5 to 24 hours are preferable.

The number average molecular weight of the polyimide in the present invention is usually 5000 to 50000, preferably 7000 to 30000. When the number average molecular weight is less than 5,000, the film formability and the mechanical strength of the film are insufficient, and when it exceeds 50,000, the coatability deteriorates due to an increase in viscosity.
The polydispersity (weight average molecular weight divided by number average molecular weight) is usually 10 or less, preferably 5 or less. If the polydispersity is too large, the proportion of low molecular weight components increases, and film formability and film mechanical strength may be insufficient.
The number average molecular weight can be adjusted by appropriately selecting conditions such as the charged molar ratio and concentration of diamine and tetracarboxylic dianhydride, reaction time, and the like as described above.
The number average molecular weight and weight average molecular weight in the present invention are measured by gel permeation chromatography (GPC) using polyethylene glycol as a standard substance.

  The liquid polyimide composition of the present invention contains a polyimide having a substituent represented by the general formula (1) and an organic solvent as essential components. It is recommended that the content of the organic solvent is adjusted so that the weight concentration of the polyimide is preferably 5 to 50% by weight, more preferably 10 to 40% by weight. If the concentration is lower than the above concentration range, it may be difficult to form a uniform coating film. In addition, when the concentration is higher than the above-described concentration range, the storage stability such as precipitation of polyimide may be deteriorated.

  The method for preparing the liquid polyimide composition of the present invention is not particularly limited. For example, (i) a method of directly using the polymerization solution obtained by the imidation reaction as the liquid polyimide composition of the present invention, (ii) Examples include a method of preparing a once-isolated polyimide by re-dissolving in a desired organic solvent.

  Among the methods for preparing the liquid polyimide composition, the method (ii) is preferable in that the amount of residual impurities such as unreacted raw materials and imidizing agents can be reduced. As a method for isolating the polyimide, a method in which the polymerization solution is added to a poor solvent for polyimide and re-precipitated to be isolated as a powder is preferable.

  Examples of the poor solvent used for reprecipitation include water, methanol, 2-propanol, hexane, and diethyl ether. These poor solvents may be used alone or in combination of two or more, and the amount used is appropriately selected within a range in which the polyimide can be insolubilized.

  After reprecipitation, the polyimide composition of the present invention can be obtained by removing the solvent by filtration and drying to obtain a polyimide powder and then dissolving it again in a desired organic solvent.

  In the liquid polyimide composition of the present invention, other components commonly used in the coating material field such as an antioxidant, a flame retardant, a leveling agent, and a defoaming agent are added as necessary as long as the effects of the invention are not impaired. Can be added.

  In the liquid polyimide composition of the present invention, the substituent represented by the general formula (1) in the polyimide is subjected to heat treatment after the coating step on the base material, and the following general formula (3) or ( By being converted into the substituent represented by 4), a polyimide film having high heat resistance can be provided.

R ¹ in the general formulas (3) and (4) is the same as R ¹ in the substituent represented by the general formula (1) before thermal dissociation of the ester group.

  There is no restriction | limiting in particular in the application | coating method used at said application | coating process, According to the form of the desired polyimide film, it can select and use a well-known application | coating method suitably. Specific examples include spin coating, spray coating, dip coating and other coating methods, drop cast coating methods, bar coater or doctor blade knife coater coating methods, screen printing, inkjet printing, and other printing techniques. It is done.

  As a base material which apply | coats a liquid polyimide composition, if it has the heat resistance in the heat processing temperature of the following process, it will not specifically limit. For example, a glass substrate, a silicon substrate, a metal substrate such as copper or stainless steel, a resin substrate such as polyimide, polyethylene naphthalate, or polyethersulfone is used.

  As a heat treatment method for the applied liquid polyimide composition, a conventionally known method can be used. For example, a heat treatment using a hot air drier, a heat reduced pressure drier or a hot plate is appropriately used.

  The temperature of the heat treatment may be a temperature at which the substituent represented by the general formula (1) in the polyimide can be converted to the substituent represented by the general formula (3) or the general formula (4) by dissociation of the ester group. However, the temperature is preferably 120 to 250 ° C, more preferably 150 to 200 ° C. When the temperature is lower than the above temperature range, the conversion rate of the substituent represented by the general formula (1) in the polyimide into the substituent represented by the general formula (3) or the general formula (4) (hereinafter referred to as an ester group) The dissociation rate is reduced), and the heat resistance of the polyimide film tends to be insufficient. Further, when the temperature is higher than the above temperature range, the polyimide film tends to be warped or deformed.

The dissociation rate of the ester group is preferably 80% or more, more preferably 90% or more, from the viewpoint of the cohesive strength of the polyimide and the heat resistance of the polyimide film.
The dissociation rate of the ester group can be determined from the peak intensity derived from the ester group in the infrared spectroscopic measurement before and after the heat treatment.

  Although the heat treatment time depends on the heating temperature and the desired form of the polyimide film, the dissociation rate of the ester group is appropriately selected within a range that satisfies the above ratio, and is preferably 0.5 to 24 hours. When the heating time is shorter than 0.5 hours, the carboxylic acid and solvent by-produced by thermal dissociation are insufficiently removed, which may adversely affect the insulation properties and heat resistance of the polyimide film. Further, if it is longer than 25 hours, the polyimide film may be warped or deformed.

  Although the solvent contained in the liquid polyimide composition of the present invention is usually removed by volatilization in the heat treatment step, preliminary drying may be performed before the heat treatment step. The predrying method, time and temperature are appropriately selected according to the boiling point and volatility of the solvent used. In the case of performing preliminary drying, it is preferable to perform at a normal pressure under a low temperature of 60 ° C. or less from the viewpoint of suppressing voids.

  The polyimide film obtained by the above production method usually exhibits a glass transition temperature of 200 ° C. or higher and has excellent heat resistance.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to these. Hereinafter, unless otherwise specified, “%” means “% by weight” and “part” means “part by weight”.

Production Example 1 <Synthesis of bis [2- {1- (2-ethylbutanoyloxy) ethyl} -4-aminophenyl] ether (ODA1)>
(1) Synthesis of bis (2-carboxy-4-nitrophenyl) ether:
To a 200 mL two-necked flask equipped with a condenser tube, 24.2 parts of 2-chloro-5-nitrobenzoic acid, 40 parts of dimethyl sulfoxide, 1 part of water, 20.5 parts of potassium carbonate, and 0.45 part of potassium fluoride were added. This mixture was stirred and reacted at 160 ° C. for 30 hours under a nitrogen stream. The reaction mixture was cooled to room temperature, poured into 200 mL of water, concentrated hydrochloric acid was added until the pH of the solution reached 2, and the precipitated solid was separated by filtration. This was recrystallized from hot water and vacuum dried to obtain 15.2 parts (yield 73%) of bis (2-carboxy-4-nitrophenyl) ether.

(2) Synthesis of bis (2-chlorocarbonyl-4-nitrophenyl) ether:
To a 300 mL two-necked flask equipped with a condenser, 13.9 parts of the above bis (2-carboxy-4-nitrophenyl) ether, 20 parts of dimethylformamide and 120 parts of thionyl chloride are added, and the mixture is refluxed at 85 ° C. for 10 hours. It was. Unreacted thionyl chloride and dimethylformamide were distilled off under reduced pressure to obtain 14.4 parts of bis (2-chlorocarbonyl-4-nitrophenyl) ether (yield 93%).

(3) Synthesis of bis (2-acetyl-4-nitrophenyl) ether:
To a 300 mL two-necked flask, 6.4 parts of bis (2-dimethylaminoethyl) ether and 60 parts of tetrahydrofuran were added, and 40 parts of a 1M methylmagnesium bromide tetrohydrofuran solution was added to this mixture at 0 ° C. The complex was obtained by reaction. The mixed solution was cooled to −60 ° C., and 80 parts of a tetrohydrofuran solution of 6.6 parts of the above bis (2-chlorocarbonyl-4-nitrophenyl) ether was slowly added dropwise over 30 minutes. After completion of the dropwise addition, the temperature was raised to 0 ° C., and 50 parts of a saturated aqueous ammonium chloride solution was added. The organic layer was extracted with ethyl acetate, and the solid obtained by distilling off the solvent was reprecipitated into hexane, whereby 5.2 parts of bis (2-acetyl-4-nitrophenyl) ether (yield 88). %).

(4) Synthesis of bis [2- (1-hydroxyethyl) -4-nitrophenyl] ether:
In a 200 mL two-necked flask, add 5.2 parts of the above bis (2-acetyl-4-nitrophenyl) ether and 100 parts of tetrohydrofuran and stir at room temperature with 2.2 parts of sodium borohydride divided into 4 portions. Added. After 2 hours of reaction at room temperature, 100 mL of water was added, and the organic layer was extracted with ethyl acetate. The solid obtained by distilling off the solvent was reprecipitated in hexane to obtain 5.2 parts of bis [2- (1-hydroxyethyl) -4-nitrophenyl] ether (99% yield). It was.

(5) Synthesis of bis [2- {1- (2-ethylbutanoyloxy) ethyl} -4-nitrophenyl] ether:
To a 200 mL two-necked flask was added 5.2 parts of the above bis [2- (1-hydroxyethyl) -4-nitrophenyl] ether, 30 parts of tetrahydrofuran, 2.4 parts of pyridine and 0.1 part of 4-dimethylaminopyridine, Cooled to 0 ° C. To this mixture, 4.1 parts of 2-ethylbutyryl chloride was slowly added dropwise and reacted at 0 ° C. for 1 hour. After further reaction at room temperature for 4 hours, the reaction mixture was poured into 200 mL of ethyl acetate, and the solid was filtered off. The filtrate was washed with 0.1 M dilute hydrochloric acid, and the solvent was distilled off to obtain 8.0 parts of bis [2- {1- (2-ethylbutanoyloxy) ethyl} -4-nitrophenyl] ether (yield). 96%).

(6) Synthesis of bis [2- {1- (2-ethylbutanoyloxy) ethyl} -4-aminophenyl] ether (ODA1):
In a 300 mL two-necked flask, 8.0 parts of the above bis [2- {1- (2-ethylbutanoyloxy) ethyl} -4-nitrophenyl] ether, 100 parts of ethanol and 30 parts of stannous chloride dihydrate were added. In addition, the mixture was refluxed at 80 ° C. for 4 hours under a nitrogen atmosphere. The reaction mixture was cooled to room temperature, poured into 100 parts of ice water, and 1M NaOH aqueous solution was added until the pH of the solution reached 8. The organic layer is extracted with ethyl acetate, and the solid obtained by distilling off the solvent is purified by silica gel column chromatography [hexane / ethyl acetate = 3: 1 (volume ratio)] to give bis [2- {1. 6.4 parts (yield 90%) of-(2-ethylbutanoyloxy) ethyl} -4-aminophenyl] ether (ODA1) were obtained.

Production Example 2 <Synthesis of bis [2- {1- (2-ethylbutanoyloxy) propyl} -4-aminophenyl] ether (ODA2)>
Except that 40 parts of 1M ethylmagnesium bromide tetrohydrofuran solution was used instead of 40 parts of 1M methylmagnesium bromide tetrohydrofuran solution, the same operations as in (1) to (3) of Production Example 1 were performed, and bis 5.5 parts (yield 86%) of (2-propionyl-4-nitrophenyl) ether were obtained.
In the same manner as in (4) of Production Example 1, except that 5.2 parts of bis (2-acetyl-4-nitrophenyl) ether is replaced with 5.5 parts of bis (2-propionyl-4-nitrophenyl) ether, 5.5 parts (99% yield) of [2- (1-hydroxypropyl) -4-nitrophenyl] ether were obtained.
Production Example 1 except that 5.2 parts of bis [2- (1-hydroxyethyl) -4-nitrophenyl] ether is replaced with 5.5 parts of bis [2- (1-hydroxypropyl) -4-nitrophenyl] ether In the same manner as in (5), 8.2 parts (yield 97%) of bis [2- {1- (2-ethylbutanoyloxy) propyl} -4-nitrophenyl] ether was obtained.
8.0 parts of bis [2- {1- (2-ethylbutanoyloxy) ethyl} -4-nitrophenyl] ether was replaced with bis [2- {1- (2-ethylbutanoyloxy) propyl} -4-nitro. Bis [2- {1- (2-ethylbutanoyloxy) propyl} -4-aminophenyl] ether (ODA2) in the same manner as in Production Example 1 (6) except that 8.2 parts of phenyl] ether were used. 6.5 parts (yield 88%) were obtained.

Production Example 3 <Synthesis of bis [2- {1- (2-ethylhexanoyloxy) propyl} -4-aminophenyl] ether (ODA3)>
The same operation as in Production Example 2 was performed except that 5.0 parts of 2-ethylhexanoyl chloride was used instead of 4.1 parts of 2-ethylbutyryl chloride, and bis [2- {1- (2-ethyl) was obtained. 8.8 parts (yield 96%) of hexanoyloxy) propyl} -4-nitrophenyl] ether were obtained.
8.0 parts of bis [2- {1- (2-ethylbutanoyloxy) ethyl} -4-nitrophenyl] ether was replaced with bis [2- {1- (2-ethylhexanoyloxy) propyl} -4-nitro. Bis [2- {1- (2-ethylhexanoyloxy) propyl} -4-aminophenyl] ether (ODA3) in the same manner as in Production Example 1 (6) except that 8.8 parts of phenyl] ether were used. 6.9 parts (yield 87%) were obtained.

Example 1 <Preparation of Liquid Polyimide Composition PMDA-ODA1>
In a 300 mL two-necked flask, 5.3 parts of bis [2- {1- (2-ethylbutanoyloxy) ethyl} -4-aminophenyl] ether (ODA1) obtained in Production Example 1 and 30 parts of N-methylpyrrolidone. Was added to make a homogeneous solution, and then 2.4 parts of pyromellitic dianhydride (PMDA) was added, followed by a polymerization reaction by stirring at room temperature for 8 hours in a nitrogen atmosphere. To the obtained polyamic acid solution, 4.2 parts of acetic anhydride and 3.3 parts of pyridine were added as imidizing agents and reacted at 60 ° C. for 4 hours to obtain a polyimide solution. This solution was poured into a large amount of methanol, and the resulting precipitate was filtered off and dried to obtain 6.8 parts of polyimide powder (yield 93%). The obtained polyimide powder was dissolved in N-methylpyrrolidone to a concentration of 20% to obtain a liquid polyimide composition PMDA-ODA1.

Example 2 <Preparation of Liquid Polyimide Composition PMDA-ODA2>
Instead of 5.3 parts of ODA1, 5.6 parts of bis [2- {1- (2-ethylbutanoyloxy) propyl} -4-aminophenyl] ether (ODA2) obtained in Production Example 2 were used. Except for the above, the same operation as in Example 1 was performed to obtain a liquid polyimide composition PMDA-ODA2.

Example 3 <Preparation of Liquid Polyimide Composition PMDA-ODA3>
Instead of 5.3 parts of ODA1, 6.1 parts of bis [2- {1- (2-ethylhexanoyloxy) propyl} -4-aminophenyl] ether (ODA3) obtained in Production Example 3 was used. Except for the above, the same operation as in Example 1 was performed to obtain a liquid polyimide composition PMDA-ODA3.

Example 4 <Preparation of Liquid Polyimide Composition BPDA-ODA3>
Example 3 with the exception that 3.2 parts of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) was used instead of 2.4 parts of pyromellitic dianhydride (PMDA). The same operation was performed to obtain a liquid polyimide composition BPDA-ODA3.

Example 5 <Preparation of Liquid Polyimide Composition BTDA-ODA3>
Example 3 with the exception that 3.5 parts of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) was used instead of 2.4 parts of pyromellitic dianhydride (PMDA). The same operation was performed to obtain a liquid polyimide composition BTDA-ODA3.

Comparative Example 1 <Preparation of Liquid Polyimide Composition PMDA-ODA>
Except for using 2.2 parts of 4,4′-diaminodiphenyl ether (ODA) in place of 5.3 parts of ODA1, the same operation as in Example 1 was performed to carry out the imidization reaction. Since gelation occurred, no further experiments could be performed.

Comparative Example 2 <Preparation of Liquid Polyimide Composition HPMDA-HDAM>
5.3 parts of ODA1 is 2.3 parts of 4,4′-diaminodicyclohexylmethane (HDAM), and 2.4 parts of PMDA is 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA). Except having replaced with 5 parts, operation similar to Example 1 was performed and the liquid polyimide composition was obtained.

  Table 1 shows the results of measuring the number average molecular weight, polydispersity, ester group dissociation rate, and glass transition temperature of the liquid polyimide compositions obtained in Examples 1 to 5 and Comparative Example 2 by the following measurement methods. In addition, the symbol of the compound in Table 1 is as follows.

[Abbreviation of compound]
(1) Diamine component ODA: 4,4′-diaminodiphenyl ether HDAM: 4,4′-diaminodicyclohexylmethane ODA1: bis [2- {1- (2-ethylbutanoyloxy) ethyl} -4-aminophenyl ] Ether ODA2: bis [2- {1- (2-ethylbutanoyloxy) propyl} -4-aminophenyl] ether ODA3: bis [2- {1- (2-ethylhexanoyloxy) propyl} -4- Aminophenyl] ether (2) acid anhydride component PMDA: pyromellitic dianhydride BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride BTDA: 3,3 ′, 4,4′- Benzophenone tetracarboxylic dianhydride HPMDA: 1,2,4,5-cyclohexanetetracarboxylic dianhydride

[Method for measuring number average molecular weight and polydispersity]
The polyimide compositions produced in Examples 1 to 5 and Comparative Example 2 were dried and then dissolved in dimethylformamide so as to be 0.1% to prepare a measurement sample. For the sample solution, using gel permeation chromatography (GPC), the number average molecular weight (Mn), weight average molecular weight (Mw), and polydispersity (Mw / Mn) in terms of standard polyethylene glycol are measured under the following measurement conditions. Asked.
Equipment: Shimadzu RID-6A
Column: ShodexGPC AD802-S, AD803-S, AD804-S
And AD805-S
Column temperature: 40 ° C
Eluent: (0.01 M lithium bromide + 0.01 M phosphoric acid) / dimethylformamide Flow rate: 1.0 mL / min Detector: RI

[Method for measuring dissociation rate of ester group]
The liquid polyimide compositions prepared in Examples 1 to 5 were applied on a slide glass (76 mm × 26 mm, thickness 1.0 mm) using a bar coater (No. 6). The coating film was naturally dried at room temperature for 12 hours, followed by hot-air drying (heat treatment) at 180 ° C. for 30 minutes under a nitrogen stream. Using a Fourier transform infrared spectrophotometer (Shimadzu Corporation FTIR-8400S), the degree of ester group dissociation from the change in peak intensity of ester group absorption (around 1700 cm ⁻¹ ) before and after heat treatment at 180 ° C. Was calculated.

[Measurement method of glass transition temperature]
The polyimide film obtained in the same manner as the drying operation in the measurement of the dissociation rate of the ester group was peeled off from the slide glass and then cut, and each minute using a differential thermal scanning calorimeter (Perkin Elmer DSC-7). The inflection point when the temperature was raised at a rate of 10 ° C. was taken as the glass transition temperature.

  As shown in Table 1, the polyimide film obtained using the liquid polyimide composition prepared in Examples 1 to 5 shows a glass transition temperature significantly higher than that of the polyimide film of Comparative Example 2, and has excellent heat resistance. I understand that.

  Since the liquid polyimide composition of the present invention can provide a polyimide film having excellent heat resistance, it is useful as a coating material for protection and insulation of various substrates in the field of electrical and electronic materials. In particular, it is useful as a substrate for flexible printed wiring circuits, a substrate for tape automation bonding, a protective film for semiconductor elements, and an interlayer insulating film for integrated circuits.

Claims (5)

The liquid polyimide composition containing the polyimide and organic solvent which have a substituent shown by General formula (1).

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are each independently an alkyl group having 1 to 6 carbon atoms, and * indicates that the bond attached thereto is bonded to another polyimide constituent unit. To express. ]   The liquid polyimide composition according to claim 1, wherein the polyimide is a polyimide obtained by a reaction between a diamine and tetracarboxylic dianhydride, and at least one of the diamines has a substituent represented by the general formula (1). object. The liquid polyimide composition according to claim 2, wherein the diamine is a diamine represented by the general formula (2).

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are each independently an alkyl group having 1 to 6 carbon atoms, and * indicates that the bond attached thereto is bonded to another polyimide constituent unit. To express. ]   The liquid polyimide composition according to claim 2 or 3, wherein the tetracarboxylic dianhydride is an aromatic tetracarboxylic dianhydride having 10 to 20 carbon atoms.   The polyimide film obtained by heat-processing after apply | coating the liquid polyimide composition in any one of Claims 1-4.