Polyimide resin composition and polyimide film

Abstract

To provide a polyimide resin composition containing no fluorine atom, soluble in methyl ethyl ketone and ethyl acetate, and having excellent heat resistance.SOLUTION: A polyimide resin composition containing an addition polymerization product of tetracarboxylic acid dianhydride and diamine is such that: the tetracarboxylic acid contains tetracarboxylic acid dianhydride having a bisphenol A structure; the diamine contains diamine containing an ether linkage, and diamine having a siloxane structure with a molecular weight of 500-1,000 g / mol; an amount of the tetracarboxylic acid dianhydride having a bisphenol A structure is 50 mol% or more based on the total amount of the tetracarboxylic acid dianhydride of the polyimide resin composition; and an amount of the diamine having a siloxane structure is 30-50 mol% based on the total amount of the diamine of the polyimide resin composition.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyimide resin composition and a polyimide film. [Background technology]

[0002] Generally, polyimides with excellent heat resistance are not solvent-soluble, so polyimides are produced by dissolving polyamic acid, a precursor of polyimide, in a solvent and heating it at high temperature for a long time to dehydrate and close the ring, thereby forming polyimide. However, such high-temperature heating can cause thermal degradation of other components, and insufficient heating can leave carboxylic acid residues in the polyamic acid structure, which can cause a decrease in electrical insulation when used in electronic materials. These problems can be solved by imparting solvent solubility to polyimide and using it to prepare a polyimide solution.

[0003] Therefore, various proposals have been made to obtain polyimides that are soluble in organic solvents. For example, Patent Document 1 reports that a polyimide containing an alicyclic acid dianhydride, a fluorine-containing aromatic acid dianhydride, and a fluoroalkyl-substituted benzidine as essential components is soluble in methyl ethyl ketone.

[0004] Furthermore, Patent Document 2 proposes a silicone-modified polyimide resin that dissolves in methyl ethyl ketone and has a glass transition temperature of 100° C. or less as a composition for anisotropic conductive adhesives. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] WO2019 / 073628 [Patent Document 2] Patent Publication No. 2005-126569 Summary of the Invention [Problem to be solved by the invention]

[0006] When polyimides are synthesized using raw materials containing fluorine atoms such as trifluoromethyl groups, their heat resistance and solvent solubility are improved, but these fluorine compounds fall under the PFAS regulations, and they tend to remain in the environment and accumulate in biological tissues, raising concerns about their impact on the environment and human body.However, polyimides made from raw materials that do not contain trifluoromethyl groups and are not subject to the PFAS regulations tend to be insoluble in low-boiling point solvents such as methyl ethyl ketone and ethyl acetate.

[0007] On the other hand, polyimides made from silicone diamines have excellent solvent solubility, but this leads to a decrease in the heat resistance that is a feature of polyimides. Thus, it is not easy to simultaneously achieve solubility in PFAS-free, halogen-free, low-boiling solvents, and heat resistance. In view of this issue, the present invention aims to provide a polyimide resin composition that can simultaneously achieve all of the aforementioned properties. [Means for solving the problem]

[0008] As a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by using the following resin composition.

[0009] 1) A polyimide resin composition containing an addition polymer of a tetracarboxylic dianhydride and a diamine, wherein the tetracarboxylic dianhydride contains a tetracarboxylic dianhydride containing a bisphenol A structure, the diamine contains a diamine containing an ether bond and a diamine having a siloxane structure and a molecular weight of 500 to 1000 g / mol, the amount of the tetracarboxylic dianhydride containing a bisphenol A structure relative to the total amount of the tetracarboxylic dianhydride components in the polyimide resin being 50 mol % or more, and the amount of the diamine having a siloxane structure relative to the total amount of the diamine components in the polyimide resin being 30 to 50 mol %.

[0010] 2) The polyimide resin composition according to 1), wherein the tetracarboxylic dianhydride containing a bisphenol A structure is 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride.

[0011] 3) The polyimide resin composition according to 1) or 2), wherein the diamine having an ether bond is diaminodiphenyl ether.

[0012] 4) The polyimide resin composition according to any one of 1) to 3), wherein the total amount of the tetracarboxylic dianhydrides is less than 100 mol % relative to 100 mol % of the total amount of the diamines.

[0013] 5) The polyimide resin composition according to any one of 1) to 4), characterized in that the fluorine content is 50 ppm or less.

[0014] 6) The polyimide resin composition according to any one of 1) to 5), which has a glass transition temperature of 100°C or higher.

[0015] 7) The polyimide resin composition according to any one of 1) to 6), characterized in that the polyimide resin composition is soluble in methyl ethyl ketone or ethyl acetate at a solid content concentration of 10%.

[0016] 8) A polyimide film comprising the polyimide resin composition according to any one of 1) to 7). [Effects of the Invention]

[0017] According to the present invention, it is possible to obtain a fluorine atom-free polyimide resin composition having excellent heat resistance and solvent solubility. Here, "fluorine atom-free" means that the fluorine content of the polyimide resin composition is 50 ppm or less. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will be described in detail below, but the present invention is not limited thereto.

[0019] <Polyimide resin composition> The polyimide resin composition of the present invention (hereinafter sometimes referred to as "polyimide") is obtained by cyclodehydration of a polyamic acid obtained by addition polymerization of a tetracarboxylic dianhydride (hereinafter sometimes referred to as "acid dianhydride") and a diamine. That is, the polyimide is a polycondensation product of a tetracarboxylic dianhydride and a diamine, and has a structure derived from the acid dianhydride (acid dianhydride component) and a structure derived from the diamine (diamine component).

[0020] In addition to the synthesis method of polyimide from acid dianhydride and diamine via polyamic acid, polyimide can also be synthesized by condensation via decarboxylation of diisocyanate and acid dianhydride, but in either synthesis method, the resulting polyimide has an acid dianhydride-derived structure (tetracarboxylic acid dianhydride residue) obtained by removing four carboxy groups from tetracarboxylic acid dianhydride, and a diamine-derived structure (diamine residue) obtained by removing two amino groups from diamine. Therefore, even when the starting material used in polyimide synthesis is not acid dianhydride or diamine, the structure corresponding to the tetracarboxylic acid dianhydride residue contained in the polyimide is referred to as the "acid dianhydride component," and the structure corresponding to the diamine residue is referred to as the "diamine component."

[0021] The polyimide of the present invention is a polyimide resin composition containing an addition polymer of a tetracarboxylic dianhydride and a diamine, wherein the tetracarboxylic dianhydride contains a tetracarboxylic dianhydride containing a bisphenol A structure, the diamine contains a diamine containing an ether bond and a diamine having a siloxane structure and a molecular weight of 500 to 1000 g / mol, and the amount of the tetracarboxylic dianhydride containing a bisphenol A structure relative to the total amount of the tetracarboxylic dianhydride components in the polyimide resin is preferably 50 mol % or more, and the amount of the diamine containing a siloxane structure relative to the total amount of the diamine components in the polyimide resin is preferably 30 to 50 mol %.

[0022] (acid dianhydride) The polyimide according to this embodiment contains a residue of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, which is a tetracarboxylic dianhydride containing a bisphenol A structure.

[0023] The inclusion of a bisphenol A structure-containing tetracarboxylic dianhydride residue tends to improve solubility in organic solvents. Depending on the type of fluorine-free aromatic tetracarboxylic dianhydride, the compatibility of polyimide with other resins such as acrylic (monomer) can be improved.

[0024] The ratio of the acid dianhydride residues containing a bisphenol A structure to the total amount of the acid dianhydride components of the polyimide is 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, and may be 80 mol% or more, further 85 mol% or more, or even 90 mol% or more. If the molar ratio of the acid dianhydride containing a bisphenol A structure is low, the solubility in methyl ethyl ketone or ethyl acetate may be reduced.

[0025] The polyimide according to this embodiment may further contain, as a structure derived from a tetracarboxylic dianhydride, pyromellitic dianhydride, mellophanic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride or 3,4'-oxydiphthalic anhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, or the like, within a range that does not impair its performance. The alicyclic tetracarboxylic dianhydride may include one or more selected from the group consisting of 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, and 1,1'-bicyclohexane-3,3',4,4'tetracarboxylic acid-3,4:3',4'-dianhydride.

[0026] (diamine) The polyimide according to this embodiment contains, as the diamine-derived structure, a diamine containing an ether bond and a diamine having a siloxane structure with a molecular weight of 500 to 1000 g / mol.

[0027] Examples of diamines having an ether bond include 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4-[3-(4-aminophenoxy)propyl]aniline, 4,4'-(1,4-butanediyl)diphenyl ether, 4,4'-diamino ... Oxydianiline, 2,2'-bis[(4-aminophenoxy)methyl]propane, 9,9-bis(4-(4-aminophenoxy)phenyl)fluorene, 1,4-bis(4-aminophenoxy)benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4-bis(4-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl] Sulfone, 4,4'-bis(3-aminophenoxy)biphenyl, 2,7-bis(4-aminophenoxy)naphthalene, 4-[2-(4-aminophenoxy)ethoxy]aniline, bis(aminomethyl)ether, bis(2-aminoethyl)ether, bis(3-aminopropyl)ether, bis(2-aminomethoxy)ethyl]ether, bis[2-(2-aminoethoxy)ethyl]ether, bis[2-(3-aminoprotoxy)ethyl]ether, 1,2-bis(aminomethoxy)ethane, 1,2-bis(2-aminoethoxy)ethane, 1,2-bis[2-(aminomethoxy)ethoxy]ethane, 1,2-bis[2-(2-aminoethoxy)ethoxy]ethane, ethylene glycol bis(3-aminopropyl)ether, diethylene glycol bis(3-aminopropyl)ether, triethylene glycol bis(3-aminopropyl)ether, and the like.

[0028] Among these, 4,4'-diaminodiphenyl ether and 3,4'-diaminodiphenyl ether are preferred in terms of solvent solubility and glass transition temperature.

[0029] The siloxane structure in the present invention is preferably a structure represented by the following formula (1). [ka]

[0030] In the formula, R represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a phenyl group, or a phenoxy group, and R may be different for each repeating unit.

[0031] Examples of diamines having a siloxane structure and a molecular weight of 500 to 1000 g / mol include KF-8010, DOWSIL BY 16-853U, α,ω-bis(3-aminopropyl)polydimethylsiloxane, and α,ω-bis(3-aminobutyl)polydimethylsiloxane, which tend to dissolve in methyl ethyl ketone and ethyl acetate and increase the glass transition temperature.

[0032] The polyimide according to this embodiment may contain, as a diamine component, a diamine that does not have a fluorine-containing group, an ether bond, or a siloxane structure, as long as the performance of the polyimide is not impaired. Examples of diamine components that do not have an ether bond or a siloxane structure include diamines with an alicyclic structure and diamines with a sulfone group.

[0033] Examples of diamines having an alicyclic structure include isophoronediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,2-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(aminomethyl)norbornene, 4,4'-methylenebis(cyclohexylamine), bis(4-aminocyclohexyl)methane, 4,4'-methylenebis(2-methylcyclohexylamine), adamantane-1,3-diamine, 2,6-bis(aminomethyl)bicyclo[2.2.1]heptane, 2,5-bis(aminomethyl)bicyclo[2.2.1]heptane, and 1,1-bis(4-aminophenyl)cyclohexane. The use of diamines having an alicyclic structure allows for the production of molded articles with excellent elastic modulus, transmittance, and mechanical strength.

[0034] Examples of diamines having a sulfone group include 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]diphenyl sulfone, and 4,4'-bis[4-(4-aminophenoxy)phenoxy]diphenyl sulfone.

[0035] Examples of diamines other than those mentioned above include p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, p-xylylenediamine, m-xylylenediamine, o-xylylenediamine, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, and 3,4'-diaminodiphenylmethane. ethane, 2,2-di(3-aminophenyl)propane, 2,2-di(4-aminophenyl)propane, 2-(3-aminophenyl)-2-(4-aminophenyl)propane, 1,1-di(3-aminophenyl)-1-phenylethane, 1,1-di(4-aminophenyl)-1-phenylethane, 1-(3-aminophenyl)-1-(4-aminophenyl)-1-phenylethane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4- 1,3-bis(3-aminobenzoyl)benzene, 1,3-bis(4-aminobenzoyl)benzene, 1,4-bis(3-aminobenzoyl)benzene, 1,4-bis(4-aminobenzoyl)benzene, 1,3-bis(3-amino-α,α-dimethylbenzyl)benzene, 1,3-bis(4-amino-α,α-dimethylbenzyl)benzene, 1,4-bis(3-amino-α,α-dimethylbenzyl)benzene, 1,4-bis(4-amino-α,α-dimethylbenzyl)benzene, 2,6-bis(3-aminophenoxy)benzene (i) Benzonitrile, 2,6-bis(3-aminophenoxy)pyridine, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,3-bis[4-(4-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(4-aminophenoxy)benzoyl]benzene, 1,3-bis[4-(3-aminophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-aminophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-aminophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(4-aminophenoxy )-α,α-dimethylbenzyl]benzene, 4,4'-bis[4-(4-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzophenone, 3,3'-diamino-4,4'-diphenoxybenzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 3,3'-diamino-4-biphenoxybenzophenone, 6,6'-bis(3-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane, 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane, and other aromatic diamines.

[0036] As the diamine, chain diamines such as ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane can also be used.

[0037] The ratio of the diamine containing a siloxane structure to the total amount of diamine components in the polyimide is preferably 30 mol % or more and 50 mol % or less, and may be 35 mol % or more and 45 mol % or less.

[0038] If the ratio of the diamine containing a siloxane structure is too high, the glass transition temperature tends to decrease, whereas if the ratio of the diamine containing a siloxane structure is too low, the solubility in methyl ethyl ketone or ethyl acetate may decrease.

[0039] (Preparation of Polyimide) The reaction of an acid dianhydride with a diamine produces a polyamic acid as a polyimide precursor, and the polyamic acid is then cyclized (imidized) to produce a polyimide. The method for preparing the polyamic acid is not particularly limited, and any known method can be used. For example, a polyamic acid solution can be obtained by dissolving a diamine and a tetracarboxylic dianhydride in an organic solvent so that the total molar amount of the tetracarboxylic dianhydride does not exceed the number of moles of the diamine (a molar ratio of 90:100 to 99:100) and stirring the solution.

[0040] The concentration of the polyamic acid solution is usually 3 to 35% by weight, and preferably 5 to 25% by weight. When the concentration is within this range, the polyamic acid obtained by polymerization has an appropriate molecular weight, and the polyamic acid solution has an appropriate viscosity.

[0041] In the polymerization of polyamic acid, a method of adding an acid dianhydride and a dicarboxylic acid to a diamine is preferred to suppress ring-opening of the acid dianhydride. When adding multiple types of diamines, multiple types of acid dianhydrides, or multiple types of dicarboxylic acids, they may be added all at once or in multiple portions. The physical properties of the polyimide can also be controlled by adjusting the order of addition of the monomers.

[0042] The organic solvent used in the polymerization of polyamic acid is not particularly limited as long as it does not react with diamines and dianhydrides and can dissolve polyamic acid. Examples of organic solvents include urea-based solvents such as methylurea and N,N-dimethylethylurea; sulfoxide or sulfone-based solvents such as dimethyl sulfoxide, diphenyl sulfone, and tetramethyl sulfone; amide-based solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), N,N'-diethylacetamide, N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, and hexamethylphosphoric triamide; alkyl halide solvents such as chloroform and dichloromethane; aromatic hydrocarbon solvents such as benzene and toluene; and ether-based solvents such as tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, dimethyl ether, diethyl ether, and p-cresol methyl ether. These solvents are typically used alone or in combination as needed. From the viewpoint of the solubility and polymerization reactivity of polyamic acid, DMAc, DMF, NMP, etc. are preferably used.

[0043] Polyimides are obtained by dehydration cyclization of polyamic acid, a polyimide precursor. One method for preparing polyimides from a polyamic acid solution is to add a dehydrating agent, an imidization catalyst, etc. to the polyamic acid solution and allow imidization to proceed in the solution. The polyamic acid solution may be heated to accelerate the imidization process. By mixing a solution containing polyimide produced by imidization of polyamic acid with a poor solvent, polyamideimide precipitates as a solid. By isolating the polyimide as a solid, impurities generated during the synthesis of polyamic acid, as well as residual dehydrating agents and imidization catalysts, can be washed away with a poor solvent.

[0044] The molecular weight of the polyimide (weight average molecular weight in terms of polyethylene oxide measured by gel permeation chromatography (GPC)) is preferably 5,000 to 200,000, more preferably 10,000 to 150,000, and even more preferably 20,000 to 100,000. If the molecular weight is too small, the strength of the film described below may be insufficient. If the molecular weight is too large, the solution viscosity may be high, resulting in poor handleability.

[0045] The polyimide resin composition may contain organic or inorganic low molecular weight compounds, polymeric compounds (e.g., epoxy resins), etc. The resin composition may contain flame retardants, ultraviolet absorbers, crosslinking agents, dyes, pigments, surfactants, leveling agents, plasticizers, fine particles, sensitizers, etc. The fine particles include organic fine particles such as polystyrene and polytetrafluoroethylene, inorganic fine particles such as colloidal silica, carbon, and layered silicates, and metal fine particles such as silver and copper, and may have a porous or hollow structure. The fiber reinforcing material includes carbon fiber, glass fiber, aramid fiber, etc.

[0046] The fluorine content in the polyimide is preferably 50 ppm or less, more preferably 40 ppm or less, and even more preferably 30 ppm or less, and may be zero.

[0047] From the viewpoint of heat resistance, the glass transition temperature of the film is 100° C. or higher, preferably 120° C. or higher, more preferably 130° C. or higher, and may be 140° C. or higher, further 150° C. or higher, or even 160° C. or higher. The high heat resistance of the polyimide resin can enhance the heat resistance of the resin composition.

[0048] The polyimide according to the present embodiment is preferably soluble in organic solvents, and is preferably soluble in N-methyl-2-pyrrolidone (NMP) at a concentration of 1% by weight or more. The polyimide is particularly preferably soluble in non-amide solvents as well as amide solvents such as NMP. From the viewpoint of a low boiling point and efficient drying, the polyimide of the present invention is preferably soluble in methyl ethyl ketone or ethyl acetate at a solids concentration of 10%.

[0049] <Polyimide film> Another embodiment of the present invention is a polyimide film containing the polyimide resin composition. The polyimide film may be formed by either a melting method or a solution method, but the solution method is preferred from the viewpoint of producing a film with excellent uniformity. In the solution method, a solution containing the polyimide resin composition is applied to a support, and the solvent is dried and removed to obtain a film.

[0050] The resin solution can be applied to a support by a known method using a bar coater, a comma coater, or the like. Examples of the support that can be used include a glass substrate, a metal substrate such as SUS, a metal drum, a metal belt, and a plastic film. From the viewpoint of improving productivity, it is preferable to use an endless support such as a metal drum or a metal belt, or a long plastic film as the support and produce the film by a roll-to-roll method. When using a plastic film as the support, it is sufficient to appropriately select a material that is insoluble in the solvent of the film-forming dope.

[0051] It is preferable to heat the film when drying the solvent. The heating temperature is not particularly limited as long as it can remove the solvent and prevent the resulting film from becoming discolored, and is appropriately set between room temperature and about 300°C, preferably between 50°C and 250°C, more preferably between 80°C and 220°C, and may be between 120°C and 180°C. The heating temperature may be increased stepwise. To increase the efficiency of solvent removal, the resin film may be peeled off from the support and dried after drying has progressed to a certain extent. Heating may be performed under reduced pressure to promote solvent removal.

[0052] The polyimide film according to this embodiment may be laminated by being pressed onto a flexible substrate as an insulating material or adhesive. [Example]

[0053] The following examples will be used to further explain the present invention, but the present invention is not limited to these examples.

[0054] [Polyimide manufacturing example] N-methyl-2-pyrrolidone (NMP) was placed in a separable flask and stirred under a nitrogen atmosphere. Diamine and acid dianhydride were then added in the ratios (mol %) shown in Table 1, and the mixture was stirred under a nitrogen atmosphere for 5 to 24 hours to react, yielding a polyamic acid solution with a solids concentration of 20 wt %.

[0055] 2.8 g of pyridine was added as an imidization catalyst to 40 g of polyamic acid solution, and after complete dispersion, 3.7 g of acetic anhydride was added and stirred at 90°C for 2 hours. After cooling to room temperature, the solution was poured into 200 g of isopropanol to precipitate polyimide. The resulting solid was washed with isopropanol and then dried in a vacuum oven set at 120°C for 12 hours to obtain polyimide.

[0056] [Film production example] <Examples 1 to 2, Comparative Examples 1 to 8> The polyimide obtained in the above Production Example was mixed with NMP to prepare a DMF solution with a resin content of 15% by weight. This solution was applied to a non-alkali glass plate and dried by heating at 80°C for 60 minutes and then at 180°C for 60 minutes in an air atmosphere to produce a film with a thickness of approximately 10 μm.

[0057] [evaluation] (solvent soluble) 1 g of polyimide was added to 9 g of methyl ethyl ketone or ethyl acetate, and the mixture was stirred at room temperature for 24 hours. The presence or absence of undissolved polyimide was visually confirmed, and the solvent solubility was evaluated according to the following criteria. ◯ was considered to be acceptable. 〇: No residue was left behind △: The solution became cloudy ×: Polyimide was not dissolved, or was in a gel state, or undissolved polyimide was observed. (glass transition temperature) Using a thermal analyzer "TMA7100" manufactured by Hitachi High-Tech Science, the inflection point of the dimensional change when the temperature was increased at a load of 29.4 mN and a heating rate of 10°C / min was taken as the glass transition temperature (Tg).

[0058] [Evaluation results] The polyimide composition and evaluation results are shown in Table 1.

[0059] In Table 1, the compounds are described by the following abbreviations. <Acid dianhydride> BPADA: 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride s-ODPA: 4,4'-oxydiphthalic anhydride a-BPDA: 2,3,3',4'-biphenyltetracarboxylic dianhydride 6FDA: 4,4'-(Hexafluoroisopropylidene)diphthalic anhydride <Diamine> PAM-E: 1,3-bis(3-aminopropyl)tetramethyldisiloxane KF-8010: Amino-modified organopolysiloxane 4,4'-ODA: 4,4'-diaminodiphenyl ether <Solvent> MEK: Methyl ethyl ketone AcOEt: ethyl acetate

[0060] [Table 1]

[0061] The polyimides shown in Examples 1 and 2 do not contain fluorine atoms and are not subject to PFAS regulations, are soluble in methyl ethyl ketone and ethyl acetate, and have a high glass transition temperature.

[0062] Comparative Example 1, which contains a high amount of fluorine atoms, has excellent solvent solubility and heat resistance, but is subject to PFAS regulations.

[0063] In Comparative Examples 2 and 3, in which the amount of siloxane structure-containing diamine was reduced, the solubility in solvents was insufficient, while in Comparative Example 4, in which the amount of siloxane structure-containing diamine was increased, the solvent solubility was ensured but the glass transition temperature was reduced.

[0064] In Comparative Example 5, the amount of acid dianhydride was greater than the amount of diamine, and the terminals of the polyimide molecules were acid dianhydride, resulting in reduced solvent solubility.

[0065] Comparative Example 6 did not exhibit solvent solubility because the molecular weight of the siloxane structure-containing diamine was 250 g / mol.

[0066] In Comparative Examples 7 and 8, in which an acid dianhydride not containing a bisphenol A structure was used, solvent solubility could not be ensured.

[0067] The above results demonstrate that a polyimide resin composition containing an addition polymer of an acid dianhydride containing a bisphenol A structure, a diamine containing an ether bond, and a diamine having a siloxane structure with a molecular weight of 500 to 1000 g / mol does not fall under the PFAS regulations, has excellent heat resistance, is soluble in methyl ethyl ketone and ethyl acetate, and has excellent processability.

Claims

1. A polyimide resin composition containing an addition polymer of a tetracarboxylic dianhydride and a diamine, the tetracarboxylic dianhydride contains a tetracarboxylic dianhydride containing a bisphenol A structure, the diamine contains a diamine containing an ether bond and a diamine having a siloxane structure and a molecular weight of 500 to 1000 g / mol; the amount of the tetracarboxylic acid dianhydride containing a bisphenol A structure is 50 mol % or more relative to the total amount of tetracarboxylic acid dianhydride components in the polyimide resin composition, a polyimide resin composition in which the amount of the siloxane structure-containing diamine is 30 to 50 mol % based on the total amount of diamine components in the polyimide resin composition;

2. 2. The polyimide resin composition according to claim 1, wherein the tetracarboxylic dianhydride containing a bisphenol A structure is 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride.

3. 2. The polyimide resin composition according to claim 1, wherein the diamine having an ether bond is diaminodiphenyl ether.

4. 2. The polyimide resin composition according to claim 1, wherein the total amount of said tetracarboxylic dianhydrides is less than 100 mol % relative to 100 mol % of the total amount of said diamines.

5. 2. The polyimide resin composition according to claim 1, wherein the fluorine content is 50 ppm or less.

6. 2. The polyimide resin composition according to claim 1, wherein the glass transition temperature is 100° C. or higher.

7. 2. The polyimide resin composition according to claim 1, wherein the polyimide resin composition is soluble in methyl ethyl ketone or ethyl acetate at a solids concentration of 10%.

8. A polyimide film comprising the polyimide resin composition according to any one of claims 1 to 7.

Images