Method for producing polyimide

Abstract

Provided is a production method whereby it is possible to stably polymerize a polyimide having good properties while using a dimer diamine composition as a starting material. A method for producing a polyimide using the following: as a dimer diamine composition, (a) a dimer diamine; (b) a monoamine compound obtained by substituting a terminal carboxylic acid group of a monoacid compound having 10-40 carbon atoms with a primary aminomethyl group or an amino group; and (c) an amine compound obtained by substituting a terminal carboxylic acid group of a polyacid compound having a hydrocarbon group in the range of 41-80 carbon atoms with a primary aminomethyl group or an amino group (excluding the dimer diamine), the content of (a) being 96% by weight or more, and the total of (b) and (c) being 4% or less in terms of area fraction in a chromatogram as determined by GPC measurement.

Description

[0001] This invention is a divisional application of the invention patent application filed on August 28, 2018, with application number 201810986098.0 and the invention title "Method for Manufacturing Polyimide". Technical Field

[0002] This invention relates to a method for manufacturing polyimide using dimer diamine as a raw material. Background Technology

[0003] In recent years, with the miniaturization, weight reduction, and space-saving development of electronic devices, the demand for thin, lightweight, flexible, and highly durable flexible printed circuit boards (FPCs) that withstand repeated bending has increased. FPCs can be installed three-dimensionally and at high density within limited space, thus their applications are gradually expanding in wiring, cables, connectors, and other components of moving parts in electronic devices such as hard disk drives (HDDs), digital video discs (DVDs), and smartphones.

[0004] Furthermore, the increasing functionality of electronic devices necessitates addressing the need for higher frequency signal transmission. When transmitting high-frequency signals, significant transmission losses along the transmission path can lead to signal loss or increased signal delays. Therefore, reducing transmission losses in FPCs is becoming increasingly important, requiring FPCs or adhesives designed to handle higher frequencies.

[0005] Furthermore, regarding the technology involving adhesive layers with polyimide as the main component, it has been proposed to apply cross-linked polyimide resin to the adhesive layer of a cover film. This cross-linked polyimide resin is obtained by reacting polyimide with an amine compound having at least two primary amino groups as functional groups. The polyimide is derived from a diamine compound derived from an aliphatic diamine such as a dimer acid (dimeric fatty acid) (e.g., Patent Document 1). Additionally, it has been proposed to apply a resin composition consisting of the polyimide, a thermosetting resin such as epoxy resin, and a cross-linking agent to copper-clad laminates (e.g., Patent Document 2). However, Patent Documents 1 and 2 do not consider the impact of byproducts other than the dimer diamine derived from the dimer acid contained in the raw materials.

[0006] It is known that dimer acids are obtained by using natural fatty acids such as soybean oil fatty acids, tall oil fatty acids, rapeseed oil fatty acids, and refined oleic acid, linoleic acid, linolenic acid, sinapic acid, etc., as raw materials and carrying out the Diels-Alder reaction. Polyacid compounds derived from dimer acids can be obtained as fatty acids or combinations of trimerized or higher fatty acids as raw materials (e.g., Patent Document 3).

[0007] [Existing Technical Documents]

[0008] [Patent Literature]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2013-1730

[0010] [Patent Document 2] Japanese Patent Application Publication No. 2017-119361

[0011] [Patent Document 3] Japanese Patent Application Publication No. 2017-137375 Summary of the Invention

[0012] [The problem the invention aims to solve]

[0013] As a method for controlling the physical properties of resins with polyimide as the main component, it is important to control the molecular weight of polyamic acid or polyimide, which are precursors of polyimide. However, when using dimer diamine as a raw material, it can be used in a state containing byproducts other than dimer diamine derived from dimer acid, making it difficult to control the molecular weight of polyimide within a certain range.

[0014] Therefore, the object of the present invention is to provide a manufacturing method that can stably polymerize a polyimide with good properties while using a dimer diamine as a raw material.

[0015] [Technical means to solve the problem]

[0016] Through diligent research, the inventors and others, focusing on the influence of amine compounds other than the dimer diamine on the molecular weight of polyimide in the manufacture of polyimide using a dimer diamine composition as a raw material, discovered that by controlling the amount of these amine compounds, polyimide can be manufactured stably, thus completing this invention.

[0017] That is, the present invention is a method for manufacturing polyimide, wherein the polyimide is formed by reacting a tetracarboxylic anhydride component with a diamine component containing a dimer diamine composition, wherein the dimer diamine composition is a dimer diamine whose main component is a dimer diamine formed by replacing the two terminal carboxylic acid groups of a dimer acid with primary aminomethyl or amino groups.

[0018] In the method for manufacturing the polyimide of the present invention, wherein, with respect to the dimer diamine composition, the following components (a) to (c) are:

[0019] (a) Dimeric diamine;

[0020] (b) Monoamine compounds obtained by replacing the terminal carboxylic acid group of a monocarboxylic acid compound with a carbon number in the range of 10 to 40 with a primary aminomethyl or amino group;

[0021] (c) An amine compound obtained by replacing the terminal carboxylic acid group of a polyacid compound having a hydrocarbon group in the range of 41 to 80 carbon atoms with a primary aminomethyl or amino group (except for the dimer diamine),

[0022] The content of component (a) is 96% by weight or more relative to the dimer diamine composition.

[0023] The total percentage of components (b) and (c) is less than 4%, based on the area percentage of the chromatogram determined by gel permeation chromatography of the dimer diamine composition.

[0024] The method for manufacturing the polyimide of the present invention may also be such that the area percentage of the chromatogram of component (c) is less than 3%.

[0025] The method for manufacturing the polyimide of the present invention may also be such that the ratio of the area percentages (b / c) of the chromatography plots of the components (b) and (c) is 1 or more. In such cases, the molar ratio (tetracarboxylic anhydride component / diamine component) of the tetracarboxylic anhydride component and the diamine component may also be 0.97 or more but less than 1.0.

[0026] The method for manufacturing the polyimide of the present invention may also be such that the ratio of the area percentages (b / c) of the chromatography chromatograms of the components (b) and (c) is less than 1. In such cases, the molar ratio (tetracarboxylic anhydride component / diamine component) of the tetracarboxylic anhydride component and the diamine component may be 0.97 or more and 1.1 or less.

[0027] The method for manufacturing the polyimide of the present invention may also be that the weight average molecular weight of the polyimide is in the range of 40,000 to 150,000.

[0028] [The effects of the invention]

[0029] The method for manufacturing polyimide of the present invention controls the content of amine compounds other than dimerdiamine in the dimerdiamine composition, thereby suppressing the unevenness of the weight average molecular weight of each batch of polyimide in the manufacture of polyimide using the dimerdiamine composition as a raw material. As a result, polyimide with good properties can be manufactured stably, achieving quality stabilization and yield improvement. Detailed Implementation

[0030] The embodiments of the present invention will be described in detail.

[0031] The method for manufacturing polyimide of the present invention is to imidize polyamic acid of a precursor obtained by reacting a tetracarboxylic anhydride component with a diamine component containing a dimer diamine composition, wherein the dimer diamine composition is a dimer diamine with the two terminal carboxylic acid groups of the dimer acid replaced by primary aminomethyl or amino groups as the main component.

[0032] [Tetracarboxylic anhydride component]

[0033] Examples of tetracarboxylic anhydride components used in the polyimide of embodiments of the present invention include: 3,3',4,4'-biphenyltetracarboxylic anhydride, pyromellitic dianhydride, 1,4-phenylene bis(trimethacrylate) dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic anhydride, 4,4'-oxydiphthalic anhydride, 2,3,3,4-biphenyltetracarboxylic anhydride, 2,2,3,3-benzophenone tetracarboxylic anhydride, 2,3,3,4-benzophenone tetracarboxylic anhydride or 3,3,4,4-benzophenone tetracarboxylic anhydride, 2,3,3,4-diphenyl ether tetracarboxylic anhydride, bis(2,3-dicarboxyphenyl) ether dianhydride, 3,3,4 4-p-Triphenyltetracarboxylic acid dianhydride, 2,3,3,4-p-Triphenyltetracarboxylic acid dianhydride or 2,2,3,3-p-Triphenyltetracarboxylic acid dianhydride, 2,2-bis(2,3- or 3,4-dicarboxyphenyl)propane dianhydride, bis(2,3- or 3,4-dicarboxyphenyl)methane dianhydride, bis(2,3- or 3,4-dicarboxyphenyl)sulfone dianhydride, 1,1-bis(2,3- or 3,4-dicarboxyphenyl)ethane dianhydride, 1,2,7,8-phenanthrene-tetracarboxylic acid dianhydride, 1,2,6,7-phenanthrene-tetracarboxylic acid dianhydride or 1,2,9,10-phenanthrene-tetracarboxylic acid dianhydride, 2,3,6,7-anthracene-tetracarboxylic acid dianhydride, 2,2-bis(3,4-dicarboxy) Phenyl)tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic acid dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic acid dianhydride or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic acid dianhydride, 2,3,6,7-(or 1,4,5,8-)tetrachloronaphthalene-1,4,5,8-(or 2,3,6,7-)tetracarboxylic acid dianhydride, 2,3,8,9-perylene-tetracarboxylic acid dianhydride, 3,4,9... 10-Perylene-tetracarboxylic dianhydride, 4,5,10,11-perylene-tetracarboxylic dianhydride or 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,8-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-bis(2,3-dicarboxyphenoxy)diphenylmethane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, terephthalic bis(triphthalic acid monoester anhydride), ethylene glycol bis(triphthalic acid anhydride), and other acid dianhydrides. In particular, when using 2,2,3,3-benzophenone tetracarboxylic dianhydride, 2,3,3,4-benzophenone tetracarboxylic dianhydride or 3,3,4,4-benzophenone tetracarboxylic dianhydride, the ketone group present in the molecular skeleton sometimes reacts with the amino group of component (b) or component (c) described later to form a C=N bond, which easily demonstrates the effects of the present invention.

[0034] [Dimeric diamine composition]

[0035] The dimer diamine composition used in the method of the present invention contains the following component (a) and controls the amounts of components (b) and (c).

[0036] (a) Dimeric diamine:

[0037] The dimer diamine of component (a) refers to a diamine formed by replacing the two terminal carboxylic acid groups (-COOH) of a dimer acid with primary aminomethyl (-CH2-NH2) or amino (-NH2). Dimer acids are known dicarboxylic acids obtained by intermolecular polymerization of unsaturated fatty acids. Their industrial manufacturing process is basically standardized in the industry, and they can be obtained by dimerizing unsaturated fatty acids with 11 to 22 carbons using clay catalysts, etc. Industrially available dimer acids are mainly composed of 36-carbon dicarboxylic acids obtained by dimerizing 18-carbon unsaturated fatty acids such as oleic acid, linoleic acid, and linolenic acid. Depending on the degree of purification, they contain arbitrary amounts of monomeric acids (18 carbons), trimer acids (54 carbons), and other polymeric fatty acids with 20 to 54 carbons. In addition, double bonds remain after the dimerization reaction, but in this invention, those that undergo further hydrogenation to reduce the degree of unsaturation are also included in the dimer acid.

[0038] The dimer diamine composition can be prepared by refining the content of dimer diamine in component (a) to 96% by weight or more, preferably 97% by weight or more, and more preferably 98% by weight or more. By setting the content of dimer diamine in component (a) to 96% by weight or more, the expansion of the molecular weight distribution of the polyimide can be suppressed. Furthermore, if technically possible, it is preferable that the entire (100% by weight) of the dimer diamine composition consists of dimer diamine in component (a).

[0039] (b) Monoamine compounds obtained by substituting the terminal carboxylic acid group of a monocarboxylic acid compound with 10 to 40 carbon atoms with a primary aminomethyl or amino group:

[0040] Monocarboxylic acid compounds with 10 to 40 carbon atoms are mixtures of monocarboxylic unsaturated fatty acids with 10 to 20 carbon atoms derived from dimer acid raw materials, and monocarboxylic acid compounds with 21 to 40 carbon atoms that are byproducts of dimer acid manufacturing. Monoamine compounds are obtained by replacing the terminal carboxylic acid group of these monocarboxylic acid compounds with a primary aminomethyl or amino group.

[0041] (b) The monoamine compound of the component is a component that inhibits the increase in molecular weight of the polyimide. During the polymerization of polyamic acid or polyimide, the monofunctional amino group of the monoamine compound reacts with the terminal anhydride group of the polyamic acid or polyimide, thereby sealing the terminal anhydride group and inhibiting the increase in molecular weight of the polyamic acid or polyimide.

[0042] (c) An amine compound obtained by replacing the terminal carboxylic acid group of a polybasic acid compound having a hydrocarbon group in the range of 41 to 80 carbon atoms with a primary aminomethyl or amino group (except for the dimer diamine):

[0043] Polybasic acid compounds containing hydrocarbon groups in the range of 41 to 80 carbon atoms are polybasic acid compounds whose main component is a tribasic acid compound in the range of 41 to 80 carbon atoms, which is a byproduct of the manufacture of dimer acids. Additionally, they may also contain polymeric fatty acids other than dimer acids with 41 to 80 carbon atoms. Amine compounds are obtained by replacing the terminal carboxylic acid group of these polybasic acid compounds with a primary aminomethyl or amino group.

[0044] (c) The amine compounds in the component contribute to the increase in the molecular weight of polyimide. The trifunctional or higher amino groups, primarily composed of triamines derived from trimer acids, react with the terminal anhydride groups of polyamic acid or polyimide, resulting in a sharp increase in the molecular weight of the polyimide. Additionally, amine compounds derived from polymeric fatty acids other than dimer acids with 41 to 80 carbon atoms also contribute to the increase in the molecular weight of polyimide, thus contributing to the gelation of polyamic acid or polyimide.

[0045] The diamine dimer composition was quantified using gel permeation chromatography (GPC). However, to facilitate the identification of the peak initiation, peak apex, and peak endpoint of each component in the diamine dimer composition, a sample treated with acetic anhydride and pyridine was used, and cyclohexanone was used as an internal standard. Using the sample prepared in this manner, each component was quantified by the area percentage of the GPC chromatogram. The peak initiation and peak endpoint of each component were set as the minimum values ​​of the respective peak curves, and the area percentage of the chromatogram was calculated based on these minimum values.

[0046] Furthermore, the dimer diamine composition may have a total content of 4% or more, preferably less than 4%, of components (b) and (c) based on the area percentage of the chromatogram obtained by GPC determination. By setting the total content of components (b) and (c) to 4% or less, the expansion of the molecular weight distribution of the polyimide can be suppressed.

[0047] Furthermore, the area percentage of the chromatogram of component (b) is preferably 3% or less, more preferably 2% or less, and even more preferably 1% or less. By setting it within the aforementioned range, the decrease in the molecular weight of the polyimide can be suppressed, thereby expanding the range of the molar ratio of the tetracarboxylic anhydride component and the diamine component. Moreover, component (b) may also be absent from the dimer diamine composition.

[0048] Furthermore, the area percentage of the chromatogram of component (c) is preferably 3% or less, more preferably 2% or less, and even more preferably 1% or less. By setting it within the aforementioned range, the sharp increase in the molecular weight of the polyimide can be suppressed, thereby expanding the range of the molar ratio of the tetracarboxylic anhydride component and the diamine component. Moreover, component (c) may also be absent from the dimer diamine composition.

[0049] Furthermore, when the area percentage ratio (b / c) of the chromatography chromatograms of components (b) and (c) is 1 or more, the molar ratio of the tetracarboxylic anhydride component and the diamine component (tetracarboxylic anhydride component / diamine component) is preferably 0.97 or more and less than 1.0. By setting the molar ratio to this value, it becomes easier to control the molecular weight of the polyimide.

[0050] Furthermore, when the ratio of the area percentages of the chromatography plots of components (b) and (c) is less than 1, the molar ratio of the tetracarboxylic anhydride component and the diamine component (tetracarboxylic anhydride component / diamine component) is preferably 0.97 or more and 1.1 or less. By setting this molar ratio, it becomes easier to control the molecular weight of the polyimide.

[0051] The weight-average molecular weight of the polyimide is preferably in the range of, for example, 10,000 to 200,000. Within this range, it is easier to control the weight-average molecular weight of the polyimide. Furthermore, when used as an adhesive for, for example, FPCs, the weight-average molecular weight of the polyimide is more preferably in the range of 40,000 to 150,000. When the weight-average molecular weight of the polyimide is less than 40,000, there is a tendency for poor flowability. On the other hand, if the weight-average molecular weight of the polyimide exceeds 150,000, there is a tendency for excessive viscosity and insolubility in the solvent, which can easily lead to uneven adhesive layer thickness, streaks, and other defects during coating operations.

[0052] The dimer diamine composition used in this invention is preferably refined to reduce components other than the dimer diamine. There are no particular limitations on the refining method, but known methods such as distillation or precipitation refining are preferred. Commercially available dimer diamine compositions are available before refining, such as PRIAMINE 1073 (trade name), PRIAMINE 1074 (trade name), and PRIAMINE 1075 (trade name) manufactured by Croda Japan KK.

[0053] As diamine compounds other than dimerized diamines used in polyimides, examples include aromatic diamine compounds and aliphatic diamine compounds. Specific examples of these include: 1,4-diaminobenzene (p-PDA; p-phenylenediamine), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-n-propyl-4,4'-diaminobiphenyl (m-NPB), 4-aminophenyl-4'-aminobenzoate (APAB), 2,2-bis-[4-(3-aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)]biphenyl, bis[1-(3-aminophenoxy)]biphenyl, bis[4-(3-aminophenoxy)phenyl]phenyl Methane, bis[4-(3-aminophenoxy)phenyl] ether, bis[4-(3-aminophenoxy)]benzophenone, 9,9-bis[4-(3-aminophenoxy)phenyl]fluorene, 2,2-bis-[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis-[4-(3-aminophenoxy)phenyl]hexafluoropropane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-dimethylaniline, 4,4'-methylenedi-2,6-diethylaniline, 3,3'-diaminodiphenylaniline Alkane, 3,3-diaminobiphenyl, 3,3'-dimethoxybenzidine, 3,3'-diamino-p-terphenyl, 4,4-[1,4-phenylenebis(1-methylethylene)]bisaniline, 4,4-[1,3-phenylenebis(1-methylethylene)]bisaniline, bis(p-aminocyclohexyl)methane, bis(p-β-amino-tert-butylphenyl) ether, bis(p-β-methyl-δ-aminopentyl)benzene, p-bis(2-methyl-4-aminopentyl)benzene, p-bis(1,1-dimethyl-5-aminopentyl)benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4- Diamine compounds such as bis(β-amino-tert-butyl)toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylenediamine, p-xylenediamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, 2-methoxy-4,4-diaminobenzonitridine, 4,4-diaminobenzonitridine, 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, 6-amino-2-(4-aminophenoxy)benzoxazole, and 1,3-bis(3-aminophenoxy)benzene.

[0054] Polyimide can be manufactured by reacting the tetracarboxylic dianhydride with a diamine compound in a solvent, followed by heating to close the ring after the formation of polyamic acid. For example, polyamic acid, a precursor of polyimide, can be obtained by dissolving the tetracarboxylic dianhydride and the diamine compound in an approximately equimolar amount in an organic solvent, stirring at a temperature ranging from 0°C to 100°C for 30 minutes to 24 hours, and then carrying out a polymerization reaction. During the reaction, the reactants are dissolved in an organic solvent at a concentration ranging from 5% to 50% by weight, preferably from 10% to 40% by weight. Examples of organic solvents used in polymerization reactions include: N,N-dimethylformamide (DMF), N,N-diethylacetamide (DMAc), N,N-diethylacetamide, N-methyl-2-pyrrolidinone (NMP), 2-butanone, dimethyl sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, cresol, etc. Two or more of these solvents may be used in combination, and aromatic hydrocarbons such as xylene and toluene may also be used in combination. Furthermore, there are no particular limitations on the amount of the organic solvent used, but it is preferable to adjust the concentration of the polyamic acid solution obtained by the polymerization reaction to approximately 5% to 50% by weight.

[0055] The synthesized polyamic acid is generally advantageous for use as a reaction solvent solution, but it can be concentrated, diluted, or replaced with other organic solvents as needed. Furthermore, polyamic acid generally has excellent solvent solubility, thus it can be used advantageously. The viscosity of the polyamic acid solution is preferably in the range of 500 cps to 100,000 cps. If it deviates from this range, defects such as uneven film thickness and streaks are easily produced during coating operations using a coating machine or the like.

[0056] There are no particular limitations on the method for imidizing polyamic acid to form polyimide. For example, heat treatment can preferably be performed in the solvent at a temperature range of 80°C to 400°C for 1 hour to 24 hours. Furthermore, regarding temperature, heating can be performed at a fixed temperature, or the temperature can be changed midway through the process.

[0057] [Example]

[0058] The present invention will now be specifically described through examples, but the present invention is not limited to these examples in any way. Furthermore, in the following examples, unless otherwise specified, various measurements and evaluations are based on the following.

[0059] [Methods for determining amine value]

[0060] Weigh approximately 2 g of the dimerized diamine composition into a 200 mL–250 mL Erlenmeyer flask. Using phenolphthalein as an indicator, add dropwise 0.1 mol / L ethanolic potassium hydroxide solution until the solution turns light pink, and dissolve it in approximately 100 mL of neutralized butanol. Add 3–7 drops of phenolphthalein solution while stirring with 0.1 mol / L ethanolic potassium hydroxide solution until the sample solution turns light pink. Add 5 drops of bromophenol blue solution while stirring with 0.2 mol / L hydrochloric acid / isopropanol solution until the sample solution turns yellow.

[0061] The amine value is calculated using the following formula (1).

[0062] Amine value = {(V2×C2) - (V1×C1)}×M KOH / m ···(1)

[0063] Here, the amine value is expressed in mg-KOH / g, M KOH The molecular weight of potassium hydroxide is 56.1. V and C represent the volume and concentration of the solution used in the dropwise addition, respectively. Subscripts 1 and 2 indicate a 0.1 M ethanolic potassium hydroxide solution and a 0.2 mol / L hydrochloric acid / isopropanol solution, respectively. Furthermore, m represents the sample weight in grams.

[0064] [Determination of the weight-average molecular weight (Mw) of polyimide]

[0065] The weight-average molecular weight was determined using gel permeation chromatography (using an HLC-8220GPC manufactured by Tosoh Corporation). Polystyrene was used as the standard, and tetrahydrofuran was used as the developing solvent.

[0066] [Calculation of area percentage in GPC and tomographic diagrams]

[0067] GPC was performed by pretreating 20 mg of a dimerized diamine composition with 200 μL of acetic anhydride, 200 μL of pyridine, and 2 mL of THF to a solution of 100 mg, then diluting the solution with 10 mL of THF (containing 1000 ppm cyclohexanone). The prepared sample was analyzed using a Tosoh HLC-8220 GPC (manufactured by Tosoh Corporation) under the following conditions: TSK-gel G2000HXL and G1000HXL columns, flow rate of 1 mL / min, column (oven) temperature of 40°C, and injection volume of 50 μL. Furthermore, cyclohexanone was used as a standard for elution time correction.

[0068] At this point, the residence time of the cyclohexanone main peak was adjusted from 27 minutes to 31 minutes, and the time from the start of the cyclohexanone main peak to the end of the peak was adjusted to 2 minutes. Furthermore, the residence time of the main peaks other than the cyclohexanone peak was adjusted from 18 minutes to 19 minutes, and the time from the start of the main peaks other than the cyclohexanone peak to the end of the peak was adjusted from 2 minutes to 4 minutes and 30 seconds. Components (a) to (c) were then analyzed.

[0069] (a) The component represented by the main peak;

[0070] (b) The component represented by the minimum value of the later time side of the residence time in the main peak as a reference, and the GPC peak detected at a later time;

[0071] (c) The component represented by the minimum value of the earlier time side of the residence time in the main peak as a reference and the GPC peak detected at an earlier time.

[0072] The abbreviations used in this embodiment refer to the following compounds. Furthermore, the "%" in components b and c refers to the area percentage of the chromatogram in the GPC determination.

[0073] BTDA: 3,3',4,4'-benzophenone tetracarboxylic dianhydride

[0074] DDA1: A distillation purifier of PRIAMINE 1075 manufactured by Croda Japan KK. Co., Ltd. (component a: 97 wt%, component b: 0.4%, component c: 2.1%, amine value: 206 mg KOH / g).

[0075] DDA2: A distillation purifier of PRIAMINE 1074, manufactured by Croda Japan KK. Co., Ltd. (component a: 96 wt%, component b: 0%, component c: 3.6%, amine value: 210 mg KOH / g).

[0076] DDA3: A distillation purifier of PRIAMINE 1074, manufactured by Croda Japan KK. Co., Ltd. (component a: 96 wt%, component b: 0%, component c: 3.9%, amine value: 210 mg KOH / g).

[0077] DDA4: A distillation purifier of PRIAMINE 1074, manufactured by Croda Japan KK. Co., Ltd. (component a: 96 wt%, component b: 0%, component c: 3.7%, amine value: 208 mg KOH / g).

[0078] DDA5: A distillation purifier of PRIAMINE 1075 manufactured by Croda Japan KK. Co., Ltd. (component a: 97 wt%, component b: 2.8%, component c: 1.0%, amine value: 210 mg KOH / g).

[0079] NMP: N-methyl-2-pyrrolidone

[0080] APB: 1,3-bis(3-aminophenoxy)benzene

[0081] BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane

[0082] 1,3-BAC: 1,3-bis(aminomethyl)cyclohexane

[0083] BisDA: 4,4'-[propane-2,2-dimethylbis(1,4-phenyleneoxy)]diphthalic dianhydride (manufactured by SABIC Innovative Plastics Contract Company, trade name: BisDA-1000)

[0084] Furthermore, the molecular weights of DDA1 to DDA5 are calculated using the following formula (1).

[0085] Molecular weight = 56.1 × 2 × 1000 / amine value ··· (1)

[0086] [Example 1]

[0087] A polyamic acid solution was prepared by mixing 55.55 g of BTDA (0.17203 mol), 94.45 g of DDA1 (0.17342 mol), 210 g of NMP, and 140 g of xylene in a 1000 ml split-type flask and mixing thoroughly at 40°C for 1 hour. The polyamic acid solution was then heated to 190°C and stirred for 4 hours. 140 g of xylene was added to prepare imidized polyimide solution 1 (solid composition: 30 wt%, weight average molecular weight: 84,800).

[0088] [Examples 2 to 19]

[0089] Except for the raw material composition shown in Table 1, polyimide solution 2 to polyimide solution 19 were prepared in the same manner as in Example 1.

[0090] [Table 1]

[0091]

[0092] Examples of the manufacture of polyimides with a weight average molecular weight in the range of 40,000 to 150,000 are illustrated in Examples 1 to 19.

[0093] In Examples 1, 4, 6, and 7-9, the anhydride / diamine ratio was 0.992. Here, a comparison of the weight-average molecular weight of the polyimide in Examples 1 and 7 shows that component b is a component that inhibits the increase in the weight-average molecular weight of the polyimide, or component c is a component that contributes to the increase in the weight-average molecular weight of the polyimide. A comparison of Examples 4 and 6 shows that component c is a component that contributes to the increase in the weight-average molecular weight of the polyimide.

[0094] Based on the results of Examples 7 to 9, it was confirmed that the batch-to-batch non-uniformity in the weight-average molecular weight of polyimide was small. Furthermore, based on the results of Examples 2, 3, and 5, it was confirmed that by setting the anhydride / dianhydride ratio to 1.008, the weight-average molecular weight of polyimide could be suppressed to within the range of 44,790 to 48,450. Additionally, based on the results of Examples 7, 10, and 11, it was confirmed that by reducing the anhydride / diamine ratio from 0.992 to 0.980 when the ratio of component b to component c is 1 or more, the weight-average molecular weight of polyimide could be increased from 67,820 to 108,880. On the other hand, based on the results of Examples 1, 2, and 12, it was confirmed that by increasing the anhydride / diamine ratio from 0.992 to 1.020 when the ratio of component b to component c is less than 1, the weight-average molecular weight of polyimide could be reduced from 84,800 to 40,520.

[0095] Examples 13 through 19 illustrate the use of a diamine other than the dimerized diamine composition as the diamine component. Based on the results of Examples 13 through 15, it was confirmed that as the molar ratio of APB decreased, the proportion of component c in the dimerized diamine composition increased, and the weight-average molecular weight of the polyimide also increased. Furthermore, based on the results of Examples 13 and 18, it was confirmed that by changing the anhydride / diamine ratio from 0.992 to 1.008, the weight-average molecular weight of the polyimide could be controlled to 43,300. Based on the results of Examples 16 and 17, it was confirmed that even with changes to the diamine component other than the dimerized diamine composition, the weight-average molecular weight of the polyimide could be controlled in the same way. Furthermore, based on the results of Examples 14 and 19, it was confirmed that even with changes to the anhydride / diamine ratio, the weight-average molecular weight of the polyimide could be controlled in the same way.

[0096] The embodiments of the present invention have been described in detail above for illustrative purposes, but the present invention is not limited to the embodiments described herein.

Claims

1. A method for producing a polyimide, wherein the polyimide is produced by reacting a tetracarboxylic anhydride component with a diamine component containing a dimer diamine composition, the dimer diamine composition being mainly composed of a dimer diamine obtained by substituting both terminal carboxylic acid groups of a dimer acid with a primary aminomethyl group or an amino group, and the method for producing a polyimide is characterized in that, with respect to the dimer diamine composition, the following components (a) to (c) are included: (a) a dimer diamine; (b) a monoamine compound obtained by substituting a terminal carboxylic acid group of a monobasic acid compound having a carbon number in the range of 10 to 40 with a primary aminomethyl group or an amino group; and (c) an amine compound obtained by substituting a terminal carboxylic acid group of a polybasic acid compound having a hydrocarbon group and having a carbon number in the range of 41 to 80 with a primary aminomethyl group or an amino group, wherein the component (c) does not include the dimer diamine, the content of the component (a) is 96% by weight or more with respect to the dimer diamine composition, the total of the components (b) and (c) is 4% or less in terms of the area percentage of a chromatogram in a measurement using gel permeation chromatography of the dimer diamine composition, the area percentage of the chromatogram of the component (c) is 3% or less, the ratio (b / c) of the area percentages of the chromatograms of the components (b) and (c) is 1 or more, and the molar ratio (tetracarboxylic anhydride component / diamine component) of the tetracarboxylic anhydride component and the diamine component is 0.97 or more and less than 1.0, or the ratio (b / c) of the area percentages of the chromatograms of the components (b) and (c) is less than 1, the molar ratio (tetracarboxylic anhydride component / diamine component) of the tetracarboxylic anhydride component and the diamine component is 0.97 or more and 1.1 or less, or the weight average molecular weight of the polyimide is in the range of 40,000 to 150,000. ​ ​ ​ ​ ​ ​ ​ 2. The method for producing a polyimide according to claim 1, characterized by, ​ 3. The method for producing a polyimide according to claim 1 or 2, characterized by, ​ 4. The method for producing a polyimide according to claim 1 or 2, characterized by, ​ 5. The method for producing a polyimide according to claim 1 or 2, characterized by, ​

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