Manufacturing method for polyimide resin varnish

Abstract

A method of manufacturing a polyimide resin varnish comprises step (A) described below and step (B) described below and is under a dry gas environment from the start time of step (A) to the end time of step (B). Step (A) is for polymerizing, in an organic solvent and at 100 to 210°C, a tetracarboxylic acid component including an aliphatic tetracarboxylic acid dianhydride mixture and a diamine component including an aromatic diamine, and obtaining a polymer, and step (B) is for reacting, at 60 to 130°C, an alkoxysilylamine compound with the polymer obtained in step (A).

Description

Method for producing polyimide resin varnish

[0001] The present invention relates to a method for producing a polyimide resin varnish and a method for producing a polyimide-glass laminate.

[0002] Due to their excellent mechanical properties and heat resistance, polyimide resins are being considered for a variety of applications. Recently, polyimides with excellent transparency have been developed, and products using polyimide films have been developed for image display devices such as liquid crystal displays and OLED displays. Therefore, polyimide resins that meet the performance requirements of optical materials are being developed. During the film production process, when a polyimide is applied to an inorganic support and formed into a film, it is necessary for the polyimide resin to have good adhesion to the support so that it does not peel off from the support during drying. In response to this requirement, studies are being conducted to impart reactivity to polyimide precursors.

[0003] For example, Patent Document 1 discloses an alkoxysilane-modified polyamic acid solution obtained by reacting an alkoxysilane compound containing an amino group with a polyamic acid obtained by reacting a tetracarboxylic dianhydride with an aromatic diamine in a specific ratio, with the aim of being able to form even thick films without peeling and to store them stably.

[0004] International Publication No. 2014 / 123045

[0005] From the viewpoint of moldability, a varnish containing a solvent-soluble polyimide resin is desired. Furthermore, from the viewpoint of suppressing coloration, etc., when producing a polyimide film from a varnish, it is also desirable to dry the varnish applied to the glass surface at low temperatures. However, there has been a problem in that sufficient adhesion cannot be obtained when drying at low temperatures. Therefore, there has been a need for a varnish containing a solvent-soluble polyimide resin that does not reduce the adhesion of the polyimide resin to glass even when dried at low temperatures. The present invention has been made in view of these circumstances, and an object of the present invention is to provide a method for producing a polyimide resin varnish, a polyimide resin, and a method for producing a polyimide-glass laminate, which can produce a laminate having excellent adhesion between glass and polyimide resin.

[0006] The present inventors have found that the above-mentioned problems can be solved by a production method comprising polymerizing a raw material containing an aliphatic tetracarboxylic dianhydride and an aromatic diamine at a specific temperature in a dry gas atmosphere, and then reacting the polymer with an alkoxysilylamine compound at a specific temperature, and thereby completing the present invention.

[0007] That is, the present invention relates to the following items [1] to

[13] . [1] A method for producing a polyimide resin varnish, comprising the following steps (A) and (B), wherein a dry gas atmosphere is maintained from the start of step (A) to the end of step (B): Step (A): A step of polymerizing a tetracarboxylic acid component containing an aliphatic tetracarboxylic acid dianhydride and a diamine component containing an aromatic diamine in an organic solvent at 100 to 210°C to obtain a polymer; Step (B): A step of reacting the polymer obtained in step (A) with an alkoxysilylamine compound at 60 to 130°C; [2] The method for producing a polyimide resin varnish according to item [1] above, wherein the tetracarboxylic acid component contains at least one selected from the group consisting of compounds represented by the following formula (1) and compounds represented by the following formula (2): [3] The method for producing a polyimide resin varnish according to the above [1] or [2], wherein the diamine component contains a compound represented by the following formula (3): [4] The method for producing a polyimide resin varnish according to any one of [1] to [3] above, wherein the amount of the alkoxysilylamine compound is 0.01 to 1.00 parts by mass per 100 parts by mass of the total amount of the tetracarboxylic acid component and the diamine component. [5] The method for producing a polyimide resin varnish according to any one of [1] to [4] above, wherein the alkoxysilylamine compound comprises a secondary amine having a trialkoxysilyl group. [6] The method for producing a polyimide resin varnish according to any one of [1] to [5] above, wherein the alkoxysilylamine compound comprises at least one selected from the group consisting of a compound represented by the following formula (4) and a compound represented by the following formula (5): [7] A method for producing a polyimide resin varnish according to any one of [1] to [6] above, wherein the reaction temperature in step (B) is 80 to 130°C. [8] A method for producing a polyimide resin varnish according to any one of [1] to [7] above, wherein the organic solvent comprises at least one selected from the group consisting of γ-butyrolactone and N,N-dimethylacetamide. [9] A method for producing a polyimide-glass laminate, comprising applying the polyimide resin varnish obtained by the production method according to any one of [1] to [8] above to a glass surface, heating and drying at 60 to 200°C to obtain a polyimide-glass laminate.

[10] A method for producing a polyimide-glass laminate according to [9] above, wherein the polyimide-glass laminate has a polyimide layer, and the thickness of the polyimide layer is 0.8 to 5 μm.

[11] A polyimide resin comprising a structure represented by the following general formula (6): (In formula (6), X is a tetravalent aliphatic tetracarboxylic acid residue, Y is a divalent aromatic diamine residue, Z is an alkoxysilylamino group, and Z′ is an alkoxysilylamino group or —OR 1 where n is a positive integer. 1 represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.)

[12] A polyimide resin varnish containing the polyimide resin according to

[11] above and an organic solvent.

[13] A polyimide-glass laminate obtained by laminating the polyimide resin according to

[11] above and glass.

[0008] According to the present invention, there are provided a method for producing a polyimide resin varnish that can give a laminate having excellent adhesion between glass and polyimide resin, a method for producing a polyimide resin, and a method for producing a polyimide-glass laminate.

[0009] [Method for Producing Polyimide Resin Varnish] The method for producing a polyimide resin varnish of the present invention comprises the following steps (A) and (B), and is carried out in a dry gas atmosphere from the start of step (A) to the end of step (B): Step (A): A step of polymerizing a tetracarboxylic acid component containing an aliphatic tetracarboxylic acid dianhydride and a diamine component containing an aromatic diamine in an organic solvent at 100 to 210°C to obtain a polymer; Step (B): A step of reacting the polymer obtained in step (A) with an alkoxysilylamine compound at 60 to 130°C.

[0010] In the method for producing a polyimide resin varnish of the present invention, a dry gas atmosphere is maintained from the start of step (A) to the end of step (B). Here, "the start of step (A)" refers to the time when heating begins. In other words, it refers to the time when the temperature of a solution containing a tetracarboxylic acid component, a diamine component, and an organic solvent begins to rise in order to polymerize the tetracarboxylic acid component and the diamine component. It is also preferable to carry out the process under a dry gas atmosphere when adding the tetracarboxylic acid component, the diamine component, the organic solvent, etc. to the reaction vessel. Next, "the end of step (B)" refers to the time when the reaction between the polymer and the alkoxysilylamine compound is completed and further heating does not cause any change in the reaction solution. It is preferable to heat the mixture for a sufficient time to completely complete the reaction, and then continue the process under a dry gas atmosphere until cooling begins. As described above, in this production method, a dry gas atmosphere is maintained from the start of step (A) to the end of step (B). However, the production method of the present invention also includes the case where a small amount of gas other than dry gas is mixed in, as long as it does not impair the effects of the present invention. Examples of cases where a small amount of gas other than dry gas is mixed in include cases where a small amount of air is mixed in when additional raw materials are added or when the reaction solution is sampled. The dry gas is preferably an inert gas, more preferably nitrogen gas. Here, the "dry gas" in the production method of the present invention refers to a gas having a water concentration of 20 ppm or less. The water concentration of the dry gas is preferably 10 ppm or less.

[0011] <Step (A)> In the method for producing a polyimide resin varnish of the present invention, a tetracarboxylic acid component containing an aliphatic tetracarboxylic dianhydride and a diamine component containing an aromatic diamine are first polymerized in an organic solvent at 100 to 210°C to obtain a polymer. The polymer is a polyimide. In this step, polymerization and imidization in an organic solvent allows efficient production of a varnish containing a solvent-soluble polyimide resin.

[0012] (Tetracarboxylic Acid Component) The tetracarboxylic acid component subjected to polymerization in this step contains an aliphatic tetracarboxylic acid dianhydride. Among aliphatic tetracarboxylic acid dianhydrides, the tetracarboxylic acid component subjected to polymerization in this step preferably contains at least one selected from the group consisting of compounds represented by the following formula (1) and compounds represented by the following formula (2), more preferably a compound represented by the following formula (1). Furthermore, the tetracarboxylic acid component subjected to polymerization in this step is preferably an alicyclic tetracarboxylic acid dianhydride, more preferably at least one selected from the group consisting of compounds represented by the following formula (1) and compounds represented by the following formula (2), even more preferably a compound represented by the following formula (1). The total proportion of the compound represented by the following formula (1) and the compound represented by the following formula (2) in the tetracarboxylic acid component used in this step is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and still more preferably 95 mol% or more. The upper limit of the total ratio of the compound represented by the following formula (1) and the compound represented by the following formula (2) is not particularly limited, as long as it is 100 mol% or less. When only the compound represented by the following formula (1) is used among the compounds represented by the following formula (1) and the compounds represented by the following formula (2), the ratio of the compound represented by the following formula (1) in the tetracarboxylic acid component used in this step is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and still more preferably 95 mol% or more. The upper limit of the ratio of the compound represented by the following formula (1) is not particularly limited, as long as it is 100 mol% or less.

[0013] Examples of the alicyclic tetracarboxylic dianhydride include 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyltetracarboxylic dianhydride, 5,5'-(1,4-phenylene)-bis[hexahydro-4,7-methanoisobenzofuran-1,3-dione], 5,5'-bis-2-norbornene-5,5',6,6'-tetracarboxylic-5,5',6,6'-dianhydride, and positional isomers thereof. Among these, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, which is the compound represented by formula (1), and 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, which is the compound represented by formula (2), are preferred, with 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride being more preferred. By using an alicyclic tetracarboxylic acid dianhydride, the resulting polyimide resin is soluble in a solvent, has excellent transparency, and exhibits excellent adhesion to glass. In particular, by using either or both of the compound represented by formula (1) and the compound represented by formula (2), the resulting polyimide resin is soluble in a solvent, has excellent transparency, and exhibits excellent adhesion to glass.

[0014] The tetracarboxylic acid component used in the polymerization in this step may contain a tetracarboxylic acid dianhydride other than an alicyclic tetracarboxylic acid dianhydride. Examples of such tetracarboxylic acid dianhydrides include, but are not limited to, aromatic tetracarboxylic acid dianhydrides and aliphatic tetracarboxylic acid dianhydrides. Examples of aromatic tetracarboxylic acid dianhydrides include biphenyl tetracarboxylic acid dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, pyromellitic dianhydride, 3,3',4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic acid dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride, and 2,2',3,3'-benzophenone tetracarboxylic acid dianhydride. Examples of aliphatic tetracarboxylic acid dianhydrides include 1,2,3,4-butane tetracarboxylic acid dianhydride. The tetracarboxylic acid component used in the polymerization in this step may be one type or two or more types. In this specification, the term "aromatic tetracarboxylic dianhydride" refers to a tetracarboxylic dianhydride containing one or more aromatic rings, the term "alicyclic tetracarboxylic dianhydride" refers to a tetracarboxylic dianhydride containing one or more alicyclic rings but not an aromatic ring, and the term "aliphatic tetracarboxylic dianhydride" refers to a tetracarboxylic dianhydride containing no aromatic rings, except when used together with the term "alicyclic tetracarboxylic dianhydride", which refers to a tetracarboxylic dianhydride containing neither an aromatic ring nor an alicyclic ring.

[0015] (Diamine Component) The diamine component subjected to polymerization in this step contains an aromatic diamine. Among aromatic diamines, the diamine subjected to polymerization in this step preferably contains a compound represented by the following formula (3). The diamine component subjected to polymerization in this step is preferably an aromatic diamine, and more preferably a compound represented by the following formula (3). The ratio of the compound represented by the following formula (3) in the diamine component used in this step is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, still more preferably 70 mol% or more, and still more preferably 90 mol% or more. The upper limit of the ratio of the compound represented by the following formula (3) is not particularly limited, and may be 100 mol% or less.

[0016] Examples of aromatic diamines include 1-(4-aminophenyl)-1,3,3-trimethylphenylindanamine, α,α'-bis(4-aminophenyl)-1,3-diisopropylbenzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4-aminophenyl-4-aminobenzoate, 2,2'-bis(trifluoromethyl)benzidine, 3,5-diaminobenzoic acid, 9,9-bis(4-aminophenyl)fluorene, 1,4-phenylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, 2,2'-dimethylbiphenyl-4,4'-diamine, and 4,4'-diaminodiamine. phenylmethane, 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminobenzanilide, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, N,N'-bis(4-aminophenyl)terephthalamide, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and 1,4-bis(4-aminophenoxy)benzene.

[0017] Among these, 1-(4-aminophenyl)-1,3,3-trimethylphenylindanamine, which is the compound represented by formula (3), is preferred. By using an aromatic diamine, the resulting polyimide resin is soluble in a solvent, has excellent transparency, and exhibits excellent adhesion to glass. In particular, by using the compound represented by formula (3), the resulting polyimide resin is soluble in a solvent, has excellent transparency, and exhibits excellent adhesion to glass. The 1-(4-aminophenyl)-1,3,3-trimethylphenylindanamine, which is the compound represented by formula (3), is preferably at least one selected from the group consisting of 1-(4-aminophenyl)-1,3,3-trimethylphenylindan-6-amine and 1-(4-aminophenyl)-1,3,3-trimethylphenylindan-5-amine, and it is more preferable to use both 1-(4-aminophenyl)-1,3,3-trimethylphenylindan-6-amine and 1-(4-aminophenyl)-1,3,3-trimethylphenylindan-5-amine.

[0018] Among aromatic diamines other than the compound represented by formula (3), α,α'-bis(4-aminophenyl)-1,3-diisopropylbenzene, which is a compound represented by formula (7) below, is preferred. When both the compound represented by formula (3) and the compound represented by formula (7) are used as the diamine components to be subjected to polycondensation in this step, the molar ratio of the compound represented by formula (3) to the compound represented by formula (7) [(3) / (7)] is preferably 5 / 95 to 70 / 30, more preferably 10 / 90 to 50 / 50, and even more preferably 20 / 80 to 40 / 60.

[0019] The diamine component subjected to polymerization in this step may contain a diamine other than an aromatic diamine. Examples of such diamines include, but are not limited to, alicyclic diamines and aliphatic diamines. Examples of alicyclic diamines include 1,3-bis(aminomethyl)cyclohexane and 1,4-bis(aminomethyl)cyclohexane. Examples of aliphatic diamines include ethylenediamine and hexamethylenediamine. The diamine component subjected to polymerization in this step may be one type or two or more types. In this specification, aromatic diamine refers to a diamine containing one or more aromatic rings, alicyclic diamine refers to a diamine containing one or more alicyclic rings but no aromatic rings, and aliphatic diamine refers to a diamine containing neither an aromatic ring nor an alicyclic ring.

[0020] (Polymerization Reaction) This step is a step in which a tetracarboxylic acid component containing an aliphatic tetracarboxylic dianhydride and a diamine component containing an aromatic diamine are polymerized in an organic solvent at 100 to 210°C to obtain a polymer, and the polymerization reaction in this step is preferably carried out as follows.

[0021] The polymerization reaction in this step is carried out in an organic solvent. The organic solvent used in the polymerization reaction may be any solvent capable of dissolving the polyimide to be produced, and examples thereof include aprotic solvents, phenolic solvents, ether solvents, and carbonate solvents. At least one solvent selected from the group consisting of aprotic solvents, phenolic solvents, ether solvents, and carbonate solvents is preferred.

[0022] Specific examples of aprotic solvents include amide solvents such as cyclic amides and chain amides, phosphorus-containing amide solvents, sulfur-containing solvents, ketone solvents, and ester solvents including cyclic esters. Among these, the organic solvent preferably contains at least one selected from the group consisting of cyclic amides, chain amides, and cyclic esters, more preferably contains at least one selected from the group consisting of chain amides and cyclic esters, and preferably contains a cyclic ester. Furthermore, the organic solvent is preferably at least one selected from the group consisting of cyclic amides, chain amides, and cyclic esters, more preferably at least one selected from the group consisting of chain amides and cyclic esters, and preferably is a cyclic ester.

[0023] Examples of cyclic amides include N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazolidinone, etc., with N-methyl-2-pyrrolidone being preferred. Examples of chain amides include N,N-dimethylformamide, N,N-dimethylacetamide, tetramethylurea, etc. Examples of cyclic esters include γ-butyrolactone, γ-valerolactone, etc. Other examples of ester-based solvents include 2-methoxy-1-methylethyl acetic acid. Examples of phosphorus-containing amide-based solvents include hexamethylphosphoric amide and hexamethylphosphine triamide. Examples of sulfur-containing solvents include dimethyl sulfone, dimethyl sulfoxide, and sulfolane. Examples of ketone-based solvents include acetone, methyl ethyl ketone, cyclohexanone, and methylcyclohexanone.

[0024] Specific examples of phenol-based solvents include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, etc. Specific examples of ether-based solvents include 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl]ether, tetrahydrofuran, 1,4-dioxane, etc. Specific examples of carbonate-based solvents include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, etc.

[0025] Among these specific organic solvents, the organic solvent preferably includes at least one selected from the group consisting of γ-butyrolactone, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone, more preferably includes at least one selected from the group consisting of γ-butyrolactone and N,N-dimethylacetamide, and preferably includes γ-butyrolactone. Furthermore, the organic solvent is preferably at least one selected from the group consisting of γ-butyrolactone, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone, more preferably includes at least one selected from the group consisting of γ-butyrolactone and N,N-dimethylacetamide, and preferably includes γ-butyrolactone. The above organic solvents may be used alone or in combination of two or more.

[0026] In this step, the method for polymerizing the tetracarboxylic acid component and the diamine component is not particularly limited, and known methods can be used. Specific reaction methods include (1) a method in which a solution containing the diamine component and an organic solvent and the tetracarboxylic acid component are charged into a reactor, and the mixture is stirred at 10 to 110°C for 0.5 to 30 hours as needed, and then the temperature is raised to carry out the polymerization reaction, and (2) a method in which a solution containing the diamine component and an organic solvent and the tetracarboxylic acid component are charged into a reactor, and the temperature is immediately raised to carry out the polymerization reaction.

[0027] In this step, the ratio of the amounts of the tetracarboxylic acid component and the diamine component used in producing the polyimide resin is preferably 0.9 to 1.1 moles of the diamine component per mole of the tetracarboxylic acid component. Since imidization generates water during the polycondensation reaction, it is preferable to carry out the reaction while removing the water generated during production using a Dean-Stark apparatus or the like. By carrying out such an operation, the degree of polymerization and the imidization rate can be further increased.

[0028] In the imidization reaction, a known imidization catalyst can be used. Examples of the imidization catalyst include base catalysts and acid catalysts. Examples of the base catalyst include organic base catalysts such as pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, imidazole, N,N-dimethylaniline, and N,N-diethylaniline, and inorganic base catalysts such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate. Examples of the acid catalyst include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, hydroxybenzoic acid, terephthalic acid, benzenesulfonic acid, paratoluenesulfonic acid, and naphthalenesulfonic acid. The imidization catalysts described above may be used alone or in combination of two or more. Of the above, from the viewpoint of ease of handling, base catalysts are preferred, organic base catalysts are more preferred, one or more selected from triethylamine and triethylenediamine are even more preferred, and triethylamine and triethylenediamine are even more preferred.

[0029] The polymerization reaction temperature in this polymerization step is 100 to 210°C, preferably 150 to 210°C, from the viewpoints of the reaction rate and suppression of gelation, etc. The reaction time is preferably 0.5 to 20 hours, more preferably 2 to 20 hours, even more preferably 4 to 15 hours, still more preferably 6 to 15 hours, and even more preferably 6 to 10 hours, after the start of distillation of the produced water. As described above, this polymerization step is carried out in a dry gas atmosphere. By setting the reaction time within the above range, the reaction rate is improved, and the adhesion of the resulting polyimide resin to glass can be further improved.

[0030] The concentration of the polymer (polyimide) in the reaction product (polymer solution) obtained after the polymerization reaction is preferably 1 to 50 mass %, more preferably 3 to 35 mass %, and even more preferably 5 to 30 mass %.

[0031] The weight-average molecular weight (Mw) of the polymer (polyimide) obtained in this step is preferably 300,000 or more, more preferably 400,000 or more, and even more preferably 500,000 or more, from the viewpoint of the mechanical properties of the resulting polyimide. There is no upper limit, but it is preferably 1,000,000 or less, more preferably 700,000 or less. From the same viewpoint, the number-average molecular weight is preferably 50,000 to 500,000. The weight-average molecular weight and number-average molecular weight of the polymer can be determined from standard polystyrene-equivalent values ​​measured by gel filtration chromatography.

[0032] In this polymerization step, in addition to the tetracarboxylic acid component and diamine component, a terminal blocking agent may be used. Monoamines or dicarboxylic acids are preferred as terminal blocking agents. The amount of terminal blocking agent introduced is preferably 0.0001 to 0.1 mol, more preferably 0.001 to 0.06 mol, per mol of the tetracarboxylic acid component. Preferred examples of monoamine terminal blocking agents include methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine, 3-ethylbenzylamine, aniline, 3-methylaniline, and 4-methylaniline. Of these, benzylamine and aniline are preferred. Preferred dicarboxylic acid terminal blocking agents are dicarboxylic acids, which may be partially ring-closed. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenonedicarboxylic acid, 3,4-benzophenonedicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, etc. are preferred. Of these, phthalic acid and phthalic anhydride are preferably used.

[0033] <Step (B)> The method for producing a polyimide resin varnish of the present invention includes, following step (A), a polymerization step, a step of reacting the polymer obtained in step (A) with an alkoxysilylamine compound at 60 to 130° C. By performing this step, it is possible to obtain a polyimide resin varnish that contains a solvent-soluble polyimide resin and in which the adhesion of the polyimide resin to glass is not reduced even when dried at low temperatures.

[0034] <Alkoxysilylamine Compound> The alkoxysilylamine compound to be reacted with the polymer in this step is not particularly limited, and may be an amine compound having an alkoxysilyl group in one molecule. Suitable alkoxysilylamine compounds are described below.

[0035] The alkoxysilylamine compound has an alkoxysilyl group. The alkoxysilyl group is preferably at least one selected from the group consisting of a trialkoxysilyl group, a dialkoxy(alkyl)silyl group, and a monoalkoxy(dialkyl)silyl group, and more preferably a trialkoxysilyl group. The trialkoxysilyl group is preferably at least one selected from the group consisting of a trimethoxysilyl group and a triethoxysilyl group, and more preferably a trimethoxysilyl group. By having a trialkoxysilyl group, the resulting polyimide resin is soluble in a solvent and does not lose adhesion to glass even when dried at low temperature.

[0036] The alkoxysilylamine compound may be any of primary amines, secondary amines, and tertiary amines, but is preferably at least one selected from the group consisting of primary amines and secondary amines, and more preferably secondary amines. The aliphatic tetracarboxylic dianhydrides used in the production method of the present invention as raw materials for polyimide resins have lower reactivity with amines than aromatic tetracarboxylic dianhydrides, so the alkoxysilylamine compound is required to have high nucleophilicity. However, highly nucleophilic primary amines may react with organic solvents depending on the type of organic solvent due to their high nucleophilicity. On the other hand, secondary amines do not react with organic solvents but have moderate nucleophilicity that allows them to react with aliphatic tetracarboxylic dianhydrides. Therefore, it is believed that the use of secondary amines allows for the production of polyimide resins that are soluble in solvents and do not exhibit reduced adhesion to glass even when dried at low temperatures. Therefore, the alkoxysilylamine compound preferably contains a secondary amine having a trialkoxysilyl group, and more preferably the alkoxysilylamine compound is a secondary amine having a trialkoxysilyl group. More specifically, the alkoxysilylamine compound preferably contains at least one selected from the group consisting of compounds represented by the following formula (4) and compounds represented by the following formula (5), and more preferably contains a compound represented by the following formula (4). Furthermore, the alkoxysilylamine compound is more preferably at least one selected from the group consisting of compounds represented by the following formula (4) and compounds represented by the following formula (5), and even more preferably contains a compound represented by the following formula (4). When the alkoxysilylamine compound is a compound represented by the following formula (4), the stability of the resulting polyimide resin is high. In the following formulas (4) and (5), Me is a methyl group.

[0037] The amount of the alkoxysilylamine compound used in this step is preferably 0.01 to 2.00 parts by mass, more preferably 0.01 to 1.00 parts by mass, even more preferably 0.10 to 1.00 parts by mass, still more preferably 0.15 to 1.00 parts by mass, still more preferably 0.30 to 1.00 parts by mass, still more preferably 0.50 to 1.00 parts by mass, and still more preferably 0.50 to 0.80 parts by mass, relative to 100 parts by mass of the combined total of the tetracarboxylic acid component and the diamine component used in step (A). When the amount of the alkoxysilylamine compound used is within the above range, the adhesion of the resulting polyimide resin to glass can be further improved.

[0038] The alkoxysilylamine compound is preferably added to the polymer solution obtained in step (A), and more preferably added simultaneously with the organic solvent or as an organic solvent solution to the polymer solution obtained in step (A). The organic solvent used here is preferably the organic solvent used in the polymerization reaction, and more preferably the same organic solvent as that contained in the polymer solution.

[0039] (Reaction of Polymer with Alkoxysilylamine Compound) The reaction temperature in step (B), in which the polymer is reacted with the alkoxysilylamine compound, is 60 to 130°C, preferably 70 to 130°C, more preferably 80 to 130°C, and preferably 80 to 110°C. By setting the reaction temperature in step (B) within the above range, alkoxysilyl groups can be introduced into the polyimide resin without side reactions, and the adhesion of the polyimide resin to glass can be further improved. The reaction time in step (B), in which the polymer is reacted with the alkoxysilylamine compound, may vary depending on the reaction temperature and the type of alkoxysilylamine compound, but is preferably 0.5 to 50 hours, more preferably 1 to 30 hours, and preferably 2 to 10 hours.

[0040] [Polyimide Resin] The polyimide resin varnish obtained by the method for producing the polyimide resin varnish contains a polyimide resin. The polyimide resin contains structural units derived from the tetracarboxylic acid component and structural units derived from the diamine component. Specifically, the polyimide resin preferably contains structural units derived from an alicyclic tetracarboxylic dianhydride, more preferably at least one selected from the group consisting of structural units derived from a compound represented by the following formula (1) and structural units derived from a compound represented by the following formula (2), and more preferably contains a structural unit derived from a compound represented by the following formula (1). The total proportion of structural units derived from the compound represented by the following formula (1) and structural units derived from a compound represented by the following formula (2) in the structural units derived from the tetracarboxylic acid component is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and even more preferably 95 mol% or more. The upper limit of the total ratio of the structural units derived from the compound represented by the following formula (1) and the structural units derived from the compound represented by the following formula (2) is not particularly limited, as long as it is 100 mol % or less. By including either or both of a structural unit derived from the compound represented by formula (1) and a structural unit derived from the compound represented by formula (2), the polyimide resin becomes soluble in a solvent, has excellent transparency, and exhibits excellent adhesion to glass.

[0041] The structural units derived from the tetracarboxylic acid component may include structural units derived from tetracarboxylic acid dianhydrides other than structural units derived from alicyclic tetracarboxylic acid dianhydrides. Examples of such structural units derived from tetracarboxylic acid dianhydrides include, but are not limited to, structural units derived from aromatic tetracarboxylic acid dianhydrides and structural units derived from aliphatic tetracarboxylic acid dianhydrides. The structural units derived from tetracarboxylic acid dianhydrides may be of one or more types, and may be one type or two or more types.

[0042] The polyimide preferably contains a structural unit derived from an aromatic diamine, and more preferably contains a structural unit derived from a compound represented by the following formula (3): The proportion of the structural unit derived from the compound represented by the following formula (3) in the structural units derived from the diamine is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, still more preferably 70 mol% or more, and still more preferably 90 mol% or more: There is no particular upper limit to the proportion of the structural unit derived from the compound represented by the following formula (3), as long as it is 100 mol% or less. By including a structural unit derived from the compound represented by formula (3), a polyimide resin is obtained that is soluble in a solvent, has excellent transparency, and exhibits excellent adhesion to glass. The polyimide resin may also include a structural unit derived from a compound represented by formula (7): When the composition contains both a structural unit derived from the compound represented by formula (3) and a structural unit derived from the compound represented by formula (7), the molar ratio of the structural unit derived from the compound represented by formula (3) to the structural unit derived from the compound represented by formula (7) [(3) / (7)] is preferably 5 / 95 to 70 / 30, more preferably 10 / 90 to 50 / 50, and even more preferably 20 / 80 to 40 / 60.

[0043] The diamine-derived structural unit may include a structural unit derived from a diamine other than a structural unit derived from an aromatic diamine. Such diamine-derived structural units are not particularly limited, but include structural units derived from alicyclic diamines and structural units derived from aliphatic diamines. The diamine-derived structural unit may be one or more types, and may be one type or two or more types.

[0044] The polyimide resin of the present invention includes a polyimide resin containing a structure represented by the following general formula (6). (In formula (6), X is a tetravalent aliphatic tetracarboxylic acid residue, Y is a divalent aromatic diamine residue, Z is an alkoxysilylamino group, and Z′ is an alkoxysilylamino group or —OR 1where n is a positive integer. 1 represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.

[0045] X is a tetravalent aliphatic tetracarboxylic acid residue. The "aliphatic tetracarboxylic acid residue" refers to a portion obtained by removing two acid anhydride groups (four carboxy groups) from a corresponding aliphatic tetracarboxylic acid dianhydride. The aliphatic tetracarboxylic acid dianhydride corresponding to X preferably includes at least one selected from the group consisting of compounds represented by the following formula (1) and compounds represented by the following formula (2), more preferably a compound represented by the following formula (1). The alicyclic tetracarboxylic acid dianhydride corresponding to X is preferably at least one selected from the group consisting of compounds represented by the following formula (1) and compounds represented by the following formula (2), more preferably a compound represented by the following formula (1). The total ratio of the compound represented by the following formula (1) and the compound represented by the following formula (2) in the aliphatic tetracarboxylic acid dianhydride corresponding to X is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and still more preferably 95 mol% or more. The upper limit of the total ratio of the compound represented by the following formula (1) and the compound represented by the following formula (2) is not particularly limited, as long as it is 100 mol % or less. By containing an alicyclic tetracarboxylic acid residue, the resulting polyimide resin is soluble in a solvent, has excellent transparency, and exhibits excellent adhesion to glass. In particular, by containing an alicyclic tetracarboxylic acid residue derived from either or both of the compound represented by formula (1) and the compound represented by formula (2), the resulting polyimide resin is soluble in a solvent, has excellent transparency, and exhibits excellent adhesion to glass.

[0046] Y is a divalent aromatic diamine residue. "Aromatic diamine residue" refers to a portion obtained by removing two amino groups from a corresponding aromatic diamine. The aromatic diamine corresponding to Y preferably includes a compound represented by the following formula (3). Furthermore, the aromatic diamine corresponding to Y is more preferably a compound represented by the following formula (3). The ratio of the compound represented by the following formula (3) in the aromatic diamine corresponding to Y is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, still more preferably 70 mol% or more, and even more preferably 90 mol% or more. The upper limit of the ratio of the compound represented by the following formula (3) is not particularly limited, and may be 100 mol% or less. By including an aromatic diamine residue, the polyimide resin is soluble in a solvent, has excellent transparency, and exhibits excellent adhesion to glass. In particular, by including an aromatic diamine residue derived from the compound represented by formula (3), the polyimide resin is soluble in a solvent, has excellent transparency, and exhibits excellent adhesion to glass. Furthermore, the aromatic diamine corresponding to Y may include a compound represented by formula (7) below. When the aromatic diamine corresponding to Y contains both the compound represented by formula (3) and the compound represented by formula (7), the molar ratio of the compound represented by formula (3) to the compound represented by formula (7) [(3) / (7)] is preferably 5 / 95 to 70 / 30, more preferably 10 / 90 to 50 / 50, and even more preferably 20 / 80 to 40 / 60.

[0047] Z is an alkoxysilylamino group. Z′ is an alkoxysilylamino group or —OR 1 It is. 1 represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. Here, the alkoxysilylamino group has a structure in which the adjacent carbon atom and the nitrogen of the amino group are bonded. That is, the terminal of the polyimide resin of the present invention has at least one alkoxysilylamino group. Note that the polyimide resin contained in the polyimide resin varnish obtained by the above-mentioned production method usually has a structure represented by the general formula (6) in which both Z and Z' are -OR1 Also included are polyimide resins having a structure represented by the formula: The alkoxysilyl group contained in the alkoxysilylamino group is preferably at least one selected from the group consisting of a trialkoxysilyl group, a dialkoxy(alkyl)silyl group, and a monoalkoxy(dialkyl)silyl group, with a trialkoxysilyl group being more preferred. The trialkoxysilyl group is preferably at least one selected from the group consisting of a trimethoxysilyl group and a triethoxysilyl group, with a trimethoxysilyl group being more preferred. By having a trialkoxysilyl group, the polyimide resin is soluble in a solvent and does not lose adhesion to glass even when dried at low temperatures.

[0048] The amino group of the alkoxysilylamino group may be either a secondary amino group or a tertiary amino group, with a tertiary amino group being more preferred. When the amino group of the alkoxysilylamino group is a tertiary amino group, the resulting polyimide resin is soluble in a solvent and exhibits good adhesion to glass even when dried at low temperatures. Therefore, the alkoxysilylamino group is preferably an alkoxysilylamino group corresponding to a secondary amine having a trialkoxysilyl group. The alkoxysilylamine compound corresponding to the alkoxysilylamino group preferably includes at least one selected from the group consisting of compounds represented by the following formula (4) and compounds represented by the following formula (5), more preferably a compound represented by the following formula (4). Furthermore, the alkoxysilylamine compound corresponding to the alkoxysilylamino group is more preferably at least one selected from the group consisting of compounds represented by the following formula (4) and compounds represented by the following formula (5), even more preferably a compound represented by the following formula (4). When the alkoxysilylamine compound is a compound represented by the following formula (4), the resulting polyimide resin has high stability. In the following formulas (4) and (5), Me is a methyl group.

[0049] Z' is -OR 1 It may be R 1 represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.1 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom. 1 In this case, Z' is preferably at least one selected from the group consisting of a hydroxyl group and an alkoxy group having 1 to 4 carbon atoms. n is a positive integer. n can be appropriately adjusted depending on the molecular weight of the polyimide resin and varies depending on each molecule. The average value of n is preferably 10 to 10,000, and more preferably 100 to 1,000. Although formula (6) shows only one end of the molecule constituting the polyimide resin, an aliphatic tetracarboxylic acid residue derived from an aliphatic tetracarboxylic acid may be bonded to the other end of the molecule constituting the polyimide resin, and further a substituent similar to Z or Z' may be bonded.

[0050] [Polyimide Resin Varnish] The polyimide resin varnish of the present invention is a polyimide resin varnish obtained by the above-mentioned method for producing a polyimide resin varnish, and contains a polyimide resin and an organic solvent. The polyimide resin varnish of the present invention also includes polyimide resin varnishes containing the above-mentioned polyimide resin and an organic solvent. Specifically, the polyimide resin varnish also includes polyimide resin varnishes containing a polyimide resin having a structure represented by the above-mentioned general formula (6) and an organic solvent.

[0051] The organic solvent contained in the polyimide resin varnish is the same as the organic solvent used in the step (A) or the step (B). The solution obtained in the step (B) may be used as a polyimide resin varnish as it is, or by adjusting the polyimide concentration (solid content) in the step (B) to a value suitable for the polyimide resin varnish, the solution obtained in the step (B) can be used as a polyimide resin varnish as it is.

[0052] The polyimide resin varnish is a polyimide uniformly dissolved in a solution, and the polyimide concentration (solid content) is preferably 5 to 40% by mass, more preferably 10 to 30% by mass. The viscosity (25°C) of the polyimide varnish is preferably 1 to 200 Pa·s, more preferably 1 to 100 Pa·s. The polyimide resin varnish may also contain various additives, such as inorganic fillers, adhesion promoters, release agents, flame retardants, UV stabilizers, surfactants, leveling agents, antifoaming agents, fluorescent brightening agents, crosslinking agents, polymerization initiators, and photosensitizers, as long as they do not impair the effects of the present invention.

[0053] [Polyimide-glass laminate and manufacturing method thereof] The polyimide-glass laminate of the present invention is preferably a polyimide-glass laminate obtained by applying a polyimide resin varnish to a glass surface, heating, and drying. The polyimide-glass laminate of the present invention also includes a polyimide-glass laminate obtained by laminating the polyimide resin and glass. Specifically, the polyimide-glass laminate also includes a polyimide-glass laminate obtained by laminating a polyimide resin containing a structure represented by the general formula (6) and glass. The polyimide-glass laminate of the present invention has excellent adhesion of the polyimide layer to glass.

[0054] The glass contained in the polyimide-glass laminate is plate-shaped. That is, it has a shape in which the thickness (length in the thickness direction) is shorter than the length in both the vertical and horizontal directions. The thickness of the glass may be selected appropriately depending on the application, but is preferably 0.05 to 50 mm, more preferably 0.1 to 30 mm, even more preferably 0.3 to 20 mm, and even more preferably 0.5 to 10 mm. The type of glass is not particularly limited, and alkali-free glass (borosilicate glass), alkali glass, soda glass, non-fluorescent glass, phosphate glass, borate glass, quartz, etc. can be used. To improve adhesion with the inorganic film, it is preferable that the upper surface of the glass substrate is highly flat. Specifically, the surface roughness Rmax is preferably 10 μm or less, and more preferably Rmax is 1 μm or less.

[0055] The polyimide-glass laminate has a polyimide layer. The polyimide layer is made of the polyimide resin or the polyimide contained in the polyimide resin varnish obtained by the production method. The thickness of the polyimide layer may be appropriately selected depending on the application, but is preferably 0.1 to 20 μm, more preferably 0.5 to 10 μm, even more preferably 0.8 to 5 μm, and still more preferably 1 to 2 μm.

[0056] As described above, the polyimide-glass laminate of the present invention is preferably a polyimide-glass laminate obtained by applying a polyimide resin varnish to a glass surface, followed by heating and drying. The polyimide resin varnish used here is preferably the polyimide resin varnish described above in the section [Polyimide Resin Varnish], more preferably either a polyimide resin varnish obtained by the production method of the present invention or a polyimide resin varnish containing a polyimide resin having a structure represented by formula (6) and an organic solvent, and even more preferably a polyimide resin varnish obtained by the production method of the present invention. The polyimide resin varnish can be applied to the glass surface using a glass rod or coater. After applying the varnish, the organic solvent is removed by heating and drying. Removing the organic solvent allows a polyimide layer to be formed on the glass surface. The drying temperature is preferably 50 to 250°C, more preferably 60 to 200°C, even more preferably 80 to 190°C, and even more preferably 120 to 180°C. Preheating may be performed to level the applied varnish before drying. The preheating temperature is preferably 50 to 120°C, more preferably 60 to 100°C. The polyimide resin varnish of the present invention contains a solvent-soluble polyimide resin, and the adhesion of the polyimide resin to glass does not decrease even when dried at low temperatures. Therefore, even at drying temperatures within the above-mentioned range, a polyimide-glass laminate having excellent adhesion between the polyimide layer and glass can be obtained. Furthermore, the polyimide resin varnish obtained by the production method of the present invention also contains a solvent-soluble polyimide resin, and the adhesion of the polyimide resin to glass does not decrease even when dried at low temperatures. Therefore, even at drying temperatures within the above-mentioned range, a polyimide-glass laminate having excellent adhesion between the polyimide layer and glass can be obtained. As described above, an example of a preferred method for producing a polyimide-glass laminate is a method in which the polyimide resin varnish obtained by the above-mentioned production method is applied to a glass surface, heated at 60 to 200°C, and dried to obtain a polyimide-glass laminate. The polyimide-glass laminate obtained in this manner has excellent adhesion of the polyimide layer to glass.

[0057] The polyimide-glass laminate of the present invention has excellent adhesion of the polyimide layer to glass, and therefore can be suitably used in various applications such as optical materials.

[0058] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples. The laminates obtained in the examples and comparative examples were evaluated by the methods shown below.

[0059] (1) Adhesion Evaluation Six cuts reaching the glass were made using a cutter knife on the polyimide resin surface of the polyimide-glass laminate obtained in the <Production of Polyimide-Glass Laminate> below, creating 25 grids. The cuts were spaced 1 mm apart. Cellophane tape was then firmly pressed onto the grids, and the edge of the tape was quickly peeled off at a 45° angle. Adhesion was evaluated according to the following criteria. The smaller the peeled area of ​​the polyimide resin, the better the adhesion. (Evaluation Criteria) 5: The peeled area of ​​the polyimide resin was 0% (all of the polyimide resin in the grids remained). 4: The peeled area of ​​the polyimide resin was more than 0% but less than 5%. 3: The peeled area of ​​the polyimide resin was 5% or more but less than 15%. 2: The peeled area of ​​the polyimide resin was 15% or more but less than 35%. 1: The peeled area of ​​the polyimide resin was 35% or more but less than 65%. 0: The area where the polyimide resin peeled off was 65% or more.

[0060] (2) Evaluation of Adhesion After Hot Water Immersion Polyimide-glass laminates obtained using the polyimide resin varnishes obtained in Examples 1 to 6 were used to evaluate adhesion after hot water immersion. Six cuts reaching the glass were made using a utility knife on the polyimide resin surface of the polyimide-glass laminate, creating 25 cross-cut patterns. The cuts were spaced 1 mm apart. The glass substrate was then immersed in 80°C hot water (high-temperature water) and allowed to stand for 1 hour. The water was then wiped off, and cellophane tape was firmly pressed onto the cross-cut areas. The edge of the tape was quickly peeled off at a 45° angle. Adhesion was evaluated according to the following criteria. As a result, in the laminate using the varnish of Example 1, the polyimide resin peeled off after hot water immersion and before adhesion evaluation. The laminate using the varnish of Example 2 was rated 3 on the following scale, the laminates using the varnishes of Examples 3 and 4 were rated 5 on the following scale, the laminate using the varnish of Example 5 was rated 0 on the following scale, and the laminate using the varnish of Example 6 was rated 1 on the following scale. The smaller the area of ​​peeled polyimide resin, the better the adhesion. (Evaluation Criteria) 5: The area of ​​peeled polyimide resin is 0% (all of the polyimide resin in the grid pattern remained). 4: The area of ​​peeled polyimide resin is more than 0% and less than 5%. 3: The area of ​​peeled polyimide resin is 5% or more and less than 15%. 2: The area of ​​peeled polyimide resin is 15% or more and less than 35%. 1: The area of ​​peeled polyimide resin is 35% or more and less than 65%. 0: The area of ​​peeled polyimide resin is 65% or more.

[0061] The tetracarboxylic acid components and diamine components used in the examples and comparative examples, as well as their abbreviations, are as follows: <Tetracarboxylic acid components> HPMDA: 1,2,4,5-cyclohexanetetracarboxylic dianhydride (compound represented by formula (1), manufactured by Mitsubishi Gas Chemical Company, Inc.) CBDA: cyclobutanetetracarboxylic dianhydride (compound represented by formula (2)) <Diamine components> BisAP: α,α'-bis(4-aminophenyl)-1,3-diisopropylbenzene (compound represented by formula (7), manufactured by Mitsui Fine Chemicals, Inc.) TMDA: 1-(4-aminophenyl)-1,3,3-trimethylphenylindan-6-amine / 1-(4-aminophenyl)-1,3,3-trimethylphenylindan-5-amine mixture (compound represented by formula (3), manufactured by Nippon Junryo Pharmaceutical Co., Ltd.) <Alkoxysilylamine compounds> KBM-573: N-phenyl-3-aminopropyltrimethoxysilane (compound represented by formula (4), manufactured by Shin-Etsu Chemical Co., Ltd.) TMPS: N-methyl-3-aminopropyltrimethoxysilane (compound represented by formula (5))

[0062] The abbreviations for the solvents and catalysts used in the examples and comparative examples are as follows: GBL: γ-butyrolactone (manufactured by Mitsubishi Chemical Corporation) TEA: triethylamine (manufactured by Kanto Chemical Co., Ltd.) TEDA: triethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0063] <Production of Polyimide Resin Varnish> Example 1 (Step (A): Polymerization Step) 35.1958 g (0.1318 mol) of TMDA and 77.7159 g of GBL were placed in a 300 mL five-neck round-bottom flask equipped with a stainless steel half-moon stirring blade, a nitrogen inlet tube, a Dean-Stark stirrer equipped with a condenser, a thermometer, and a glass end cap, and the mixture was stirred at 200 rpm at a system temperature of 80° C. under a dry nitrogen atmosphere (water concentration: 10 ppm or less) to obtain a solution. Dry nitrogen was introduced through the nitrogen inlet tube until a polyimide resin varnish was obtained. To this solution, 29.5593 g (0.1318 mol) of HPMDA and 14.5764 g of GBL were added all at once, followed by the addition of 0.7110 g of TEA, 0.0302 g of TEDA, and 4.9903 g of GBL as imidization catalysts, and the mixture was heated with a mantle heater until the temperature in the reaction system reached 190° C. over approximately 30 minutes. While collecting the components distilling off as the reaction proceeded, the temperature in the reaction system was maintained at 190° C. and the mixture was stirred for 3 hours, yielding a polymer solution.

[0064] (Step (B): Polyimide resin varnish production step) After adding 82.0983 g of GBL to the polymer solution, the temperature in the system was raised to 80° C., and 0.1203 g of KBM-573 and 11.8604 g of GBL were added, and the temperature in the reaction system was maintained at 80° C. while stirring for 4 hours. The obtained solution was cooled to obtain a polyimide resin varnish.

[0065] Examples 2 to 9 and Comparative Examples 5 to 6 Polyimide resin varnishes were obtained in the same manner as in Example 1, except that the types and amounts of the tetracarboxylic acid component and diamine component used in step (A) were as shown in Table 1, the reaction conditions for step (A) were as shown in Table 1, the type and amount of the alkoxysilylamine compound used in step (B) were as shown in Table 1, and the reaction conditions for step (B) were as shown in Table 1.

[0066] Comparative Examples 1 to 3 Polyimide resin varnishes were obtained in the same manner as in Example 1, except that the types and amounts of the tetracarboxylic acid component and diamine component used in step (A) were changed as shown in Table 1 and step (B) was not performed.

[0067] Comparative Example 4 A polyimide resin varnish was obtained in the same manner as in Example 1, except that in step (A), KBM-573 was added simultaneously with TMDA, and in step (B), KBM-573 was not used.

[0068] Comparative Example 7 A polyimide resin varnish was obtained in the same manner as in Example 1, except that in step (B), after GBL was added to the polymer solution, the nitrogen introduced through the nitrogen inlet tube was changed to water-containing nitrogen (water concentration: 176 ppm).

[0069] <Production of Polyimide-Glass Laminate> The polyimide resin varnish obtained in the Examples and Comparative Examples was applied by spin coating to a glass substrate, held at 80°C for 20 minutes on a hot plate, and then heated at 160°C for 60 minutes in a hot air dryer under an air atmosphere to evaporate the solvent, yielding a polyimide-glass laminate. The polyimide layer formed on the glass substrate was 5 μm thick. The glass substrate used here was AN100 glass (alkali-free glass, manufactured by AGC Inc., dimensions: 100 mm x 100 mm x 0.7 mm), which had been cleaned with water and a 1% (w / v) aqueous potassium hydroxide solution and then irradiated with UV light.

[0070]

[0071] As shown in Table 1, the polyimide-glass laminates produced using the polyimide resin varnishes of the Examples exhibited excellent adhesion between the polyimide resin and glass, despite being dried at low temperatures. It was also found that the polyimide resin varnishes of the Examples were homogeneous, and that the polyimide resin contained in the varnishes was soluble in solvents. Therefore, it was found that the polyimide resin varnish of the present invention can provide a laminate having excellent adhesion between glass and polyimide resin. It was also found that the polyimide resin varnish obtained by the production method of the present invention can provide a laminate having excellent adhesion between glass and polyimide resin.

Claims

1. A method for producing a polyimide resin varnish, comprising the following steps (A) and (B), wherein a dry gas atmosphere is maintained from the start of step (A) to the end of step (B): Step (A): A step of polymerizing a tetracarboxylic acid component containing an aliphatic tetracarboxylic dianhydride and a diamine component containing an aromatic diamine in an organic solvent at 100 to 210° C. to obtain a polymer. Step (B): A step of reacting the polymer obtained in step (A) with an alkoxysilylamine compound at 60 to 130° C.

2. The method for producing a polyimide resin varnish according to claim 1, wherein the tetracarboxylic acid component comprises at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2): 【Chemistry 1】

3. The method for producing a polyimide resin varnish according to claim 1 , wherein the diamine component contains a compound represented by the following formula (3): 【Chemistry 2】

4. 2. The method for producing a polyimide resin varnish according to claim 1, wherein the amount of the alkoxysilylamine compound is 0.01 to 1.00 parts by mass per 100 parts by mass of the total amount of the tetracarboxylic acid component and the diamine component.

5. The method for producing a polyimide resin varnish according to claim 1 , wherein the alkoxysilylamine compound contains a secondary amine having a trialkoxysilyl group.

6. The method for producing a polyimide resin varnish according to claim 1, wherein the alkoxysilylamine compound comprises at least one selected from the group consisting of a compound represented by the following formula (4) and a compound represented by the following formula (5): 【Chemistry 3】

7. The method for producing a polyimide resin varnish according to claim 1, wherein the reaction temperature in the step (B) is 80 to 130° C.

8. The method for producing a polyimide resin varnish according to claim 1, wherein the organic solvent contains at least one selected from the group consisting of γ-butyrolactone and N,N-dimethylacetamide.

9. A method for producing a polyimide-glass laminate, comprising applying a polyimide resin varnish obtained by the method according to any one of claims 1 to 8 to a glass surface, heating and drying the resulting glass surface at 60 to 200°C, and obtaining a polyimide-glass laminate.

10. 10. The method for producing a polyimide-glass laminate according to claim 9, wherein the polyimide-glass laminate has a polyimide layer, and the polyimide layer has a thickness of 0.8 to 5 μm.

11. A polyimide resin comprising a structure represented by the following general formula (6): 【Chemistry 4】 In formula (6), X is a tetravalent aliphatic tetracarboxylic acid residue, Y is a divalent aromatic diamine residue, Z is an alkoxysilylamino group, and Z′ is an alkoxysilylamino group or —OR 1 where n is a positive integer. 1 represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.)

12. A polyimide resin varnish comprising the polyimide resin according to claim 11 and an organic solvent.

13. A polyimide-glass laminate obtained by laminating the polyimide resin according to claim 11 and glass.

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