Polyamic acid composition, method for producing the polyamic acid composition, polyimide, polyimide film, and laminate, method for producing the laminate

Abstract

To provide a polyamic acid composition containing a polyamic acid having appropriate viscosity, obtained by a good polyaddition reaction between a diamine component and a tetracarboxylic dianhydride component in an organic solvent, particularly an alcohol having an ether structure, using the organic solvent. [Solution] The present invention relates to a polyamic acid composition comprising an organic solvent and a polyamic acid which is a polyaddition reaction product of a diamine component and a tetracarboxylic dianhydride component in the organic solvent, wherein the organic solvent comprises an alcohol having an ether structure, and the diamine component comprises one or more selected from 1,3-bis(3-aminophenoxy)benzene, 2,2'-bis(trifluoromethyl)benzidine, and 3,3'-diaminodiphenylsulfone.

Description

Technical Field

[0001] The present invention relates to a polyamic acid composition containing a specific organic solvent and a polyamic acid obtained by subjecting a diamine component and a tetracarboxylic dianhydride component to a polyaddition reaction in the organic solvent.

Background Art

[0002] Polyimide is excellent in heat resistance, mechanical strength, electrical insulation, chemical resistance, etc., and is used in various electronic component materials.

[0003] Polyimide is generally obtained by reacting a diamine component and a tetracarboxylic dianhydride component in an organic solvent to form a solution containing a polyamic acid which is a polyimide precursor (also referred to as a "polyamic acid composition" or a "varnish"), and then further subjecting it to thermal or chemical ring closure. In the production of a laminate containing a polyimide film such as an electronic component material, a polyamic acid solution is applied to at least one side of a substrate (support) made of metal or the like constituting the laminate to form a coating film, and after volatilizing and removing the organic solvent, imidization is carried out to form a polyimide film. A method is known.

[0004] Here, polyimide, its precursor polyamic acid, and the diamine component and tetracarboxylic dianhydride component which are its raw material monomers have low solubility in organic solvents. Conventionally, amide solvents have been widely used as organic solvents. However, amide solvents are suspected of being carcinogenic, and it is desired to avoid their use from the viewpoint of REACH regulations and the like.

[0005] Given these circumstances, it has been proposed to use safer non-amide solvents. For example, Patent Document 1 discloses a resin composition containing a polyimide precursor (polyamic acid) and a solvent, and shows that a non-amide solvent can be used as the solvent. Specifically, examples of non-amide solvents include propylene glycol monomethyl ether (PGME) and propylene glycol-1-monomethyl ether-2-acetate (PGMEA).

[0006] However, such specific organic solvents not only affect the solubility of the polyamic acid obtained by the polyaddition reaction of the diamine component and the tetracarboxylic dianhydride component, but also influence the reactivity of the polyaddition reaction of the starting monomers. In other words, even if the organic solvent is a non-amide solvent, not all combinations of the numerous known diamine components and tetracarboxylic dianhydride components will necessarily undergo a proper polyaddition reaction in that organic solvent. Furthermore, Patent Document 1, the prior art document mentioned above, does not disclose any technical matters regarding the reactivity of the synthesis reaction of polyimide precursors in non-amide solvents.

[0007] Among the non-amide solvents mentioned above, alcoholic solvents such as propylene glycol monomethyl ether (PGME, also known as 1-methoxy-2-propanol) are known to have excellent solubility for polyamic acids. However, propylene glycol-1-monomethyl ether-2-acetate (PGMEA, an ester-based solvent), which has an ether structure similar to PGME, differs significantly from PGME not only in its solubility for polyamic acids but also in its reactivity with the diamine component and tetracarboxylic dianhydride component required for polyamic acid synthesis.

[0008] Poor reactivity in the polyaddition reaction between the diamine component and the tetracarboxylic dianhydride component in certain organic solvents can not only prevent the formation of polyamic acid with the appropriate molecular weight, but also lead to a decrease in the viscosity of the polyamic acid solution. Furthermore, poor reactivity can also cause an increase in the viscosity of the polyamic acid solution, as well as solidification or gelation.

[0009] Thus, in order to obtain a polyamic acid solution that exhibits excellent coating properties on a substrate and can form a uniform polyimide film on that substrate, not only the solubility of the synthesized polyamic acid in an organic solvent is important, but the reactivity of the diamine component and the tetracarboxylic dianhydride component in that organic solvent is also extremely important. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2024-028330 [Overview of the project] [Problems that the invention aims to solve]

[0011] This invention has been proposed in view of the above circumstances, and aims to provide a polyamic acid composition containing a polyamic acid having an appropriate viscosity, obtained by a good polyaddition reaction between a diamine component and a tetracarboxylic dianhydride component in an organic solvent, particularly an alcohol having an ether structure, in the organic solvent. [Means for solving the problem]

[0012] The inventors diligently conducted research to solve the above-mentioned problems. As a result, they discovered that by using a specific diamine component in an organic solvent containing an alcohol having an ether structure, a polyaddition reaction proceeds smoothly with the tetracarboxylic dianhydride component, resulting in a polyamic acid solution of appropriate viscosity, thus completing the present invention.

[0013] (1) The first invention of the present invention is a polyamic acid composition comprising an organic solvent and a polyamic acid which is a polyaddition reaction product of a diamine component and a tetracarboxylic dianhydride component in the organic solvent, wherein the organic solvent comprises an alcohol having an ether structure, and the diamine component comprises one or more selected from 1,3-bis(3-aminophenoxy)benzene, 2,2'-bis(trifluoromethyl)benzidine, and 3,3'-diaminodiphenylsulfone.

[0014] (2) The second invention of the present invention is a polyamic acid composition in which, in the first invention, the total content of 1,3-bis(3-aminophenoxy)benzene, 2,2'-bis(trifluoromethyl)benzidine, and 3,3'-diaminodiphenylsulfone is 80 mol% or more relative to the total amount of the diamine component.

[0015] (3) The third invention of the present invention is a polyamic acid composition in which, in the first or second invention, the tetracarboxylic dianhydride component comprises a compound having either a diphenyl ether group or a benzophenone group in its molecule.

[0016] (4) The fourth invention of the present invention is a polyamic acid composition in which, in any of the first to third inventions, the tetracarboxylic dianhydride component comprises one or more selected from 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic acid anhydride, and 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic acid anhydride.

[0017] (5) The fifth invention of the present invention is a polyamic acid composition in which, in any of the first to fourth inventions, the tetracarboxylic dianhydride component comprises one or more selected from 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, and 3,4'-oxydiphthalic anhydride.

[0018] (6) The sixth invention of the present invention is a polyamic acid composition in which, in any of the first to fifth inventions, the diamine component includes an aliphatic diamine and / or a siloxanediamine, and the content of the aliphatic diamine and the siloxanediamine is less than 5 mol% of the total amount of the diamine component.

[0019] (7) The seventh invention of the present invention is a polyamic acid composition in which, in any of the first to sixth inventions, the content of the alcohol having the ether structure is 70% by mass or more relative to the total amount of the organic solvent.

[0020] (8) The eighth invention of the present invention is a polyamic acid composition in which, in any of the first to fifth inventions, the organic solvent comprises one or more selected from propylene glycol monomethyl ether (PGME) and 1-phenoxy-2-propanol.

[0021] (9) The ninth invention of the present invention is a method for producing a polyamic acid composition comprising a polyamic acid obtained by polyaddition reaction of a diamine component and a tetracarboxylic dianhydride component in an organic solvent, wherein a diamine component comprising one or more selected from 1,3-bis(3-aminophenoxy)benzene, 2,2'-bis(trifluoromethyl)benzidine, and 3,3'-diaminodiphenylsulfone and a tetracarboxylic dianhydride component are mixed in an organic solvent containing an alcohol having an ether structure.

[0022] (10) The tenth invention of the present invention is a polyimide, which is an imide of a polyamic acid contained in the polyamic acid composition described in any of the first to eighth inventions.

[0023] (11) The eleventh invention of the present invention is a polyimide film comprising the polyimide described in the tenth invention.

[0024] (12) The twelfth invention of the present invention is a laminate having a substrate and the polyimide film described in the eleventh invention formed on one or both sides of the substrate.

[0025] (13) The thirteenth invention of the present invention is a method for manufacturing a laminate including a substrate and a polyimide film, the method including: a step of coating one or both sides of the substrate with the polyamic acid composition described in any one of the first to eighth inventions to form a coating film containing the polyamic acid; and a step of imidizing the polyamic acid by heating the coating film to form a polyimide film.

Advantages of the Invention

[0026] According to the present invention, a polyamic acid composition containing a polyamic acid having an appropriate viscosity can be provided, which is obtained by a good polyaddition reaction between a diamine component and a tetracarboxylic dianhydride component in an organic solvent containing an alcohol having an ether structure.

Embodiments for Carrying Out the Invention

[0027] Hereinafter, specific embodiments of the present invention will be described in detail. Note that the present invention is not limited to the following embodiments, and various modifications can be made without changing the gist of the present invention.

[0028] ≪1. Polyamic Acid Composition≫ The polyamic acid composition according to the present embodiment includes an organic solvent and a polyamic acid obtained by a polyaddition reaction between a diamine component and a tetracarboxylic dianhydride component in the organic solvent. Thus, the polyamic acid composition includes a specific organic solvent and a polyamic acid, which is a reaction product obtained by a good polyaddition reaction of monomer components in the organic solvent.

[0029] A "polyamic acid composition" is a solution in which polyamic acid is dissolved in an organic solvent (hereinafter also referred to as a "polyamic acid solution"), and is also called a varnish. Polyamic acid is a precursor of polyimide. The polyamic acid solution is used by coating the surface of a substrate (support) made of metal or the like, and by heating the coating film, the polyamic acid is imidized to form a polyimide film. Therefore, it is preferable that the polyamic acid solution has excellent coating properties, has an appropriate viscosity, and does not solidify or gel.

[0030] Specifically, the polyamic acid solution according to this embodiment contains an alcohol having an ether structure as an organic solvent. Furthermore, the diamine component is characterized by containing one or more selected from 1,3-bis(3-aminophenoxy)benzene, 2,2'-bis(trifluoromethyl)benzidine, and 3,3'-diaminodiphenylsulfone.

[0031] Numerous compounds are known as the diamine and tetracarboxylic dianhydride components that serve as the starting monomers for polyamic acids. When polyamic acids are synthesized by polyaddition reactions of these monomer components in organic solvents, the reactivity of the monomer components is greatly influenced by the type of organic solvent, and the reactivity in a particular organic solvent varies depending on the type and combination of starting monomers.

[0032] As a result of the inventors' research, it has been found that in an organic solvent containing an alcohol having an ether structure, using a diamine component containing one or more selected from 1,3-bis(3-aminophenoxy)benzene, 2,2'-bis(trifluoromethyl)benzidine, and 3,3'-diaminodiphenylsulfone reacts well with the tetracarboxylic dianhydride component to obtain a polyamic acid solution with appropriate viscosity. Such a polyamic acid solution exhibits excellent solubility of the polyamic acid in its organic solvent and also has excellent coating properties for substrates.

[0033] [organic solvent] The polyamic acid solution contains an alcohol having an ether structure as an organic solvent. In this embodiment, the polyamic acid solution is obtained by dissolving a polyaddition product, polyamic acid, in an organic solvent containing an alcohol having an ether structure, in which a diamine component and a tetracarboxylic dianhydride component undergo a polyaddition reaction.

[0034] Alcohols with an ether structure are non-amide solvents and, among various organic solvents, are highly safe and soluble in the resulting polyamic acid.

[0035] As will be shown in the examples described later, even in organic solvents containing alcohols with an ether structure, the reactivity of polyamic acid differs depending on the type of starting monomer, which can lead to solidification or gelation, or failure to increase viscosity to an appropriate level. Furthermore, even when polyamic acid is produced, there are significant differences in its solubility. In other words, depending on the type of organic solvent, there are significant differences in the reactivity of the starting monomer diamine component and the tetracarboxylic dianhydride component in that organic solvent.

[0036] Alcohols having an ether structure are not particularly limited, but examples include propylene glycol monomethyl ether (PGME, also known as 1-methoxy-2-propanol), 1-phenoxy-2-propanol, propylene glycol monoethyl ether (also known as 1-ethoxy-2-propanol), PG-T-butyl ether (also known as 1-(tert-butoxy)-2-propanol), 1-isopropoxy-2-propanol, 1-methoxy-2-butanol, 1-methoxy-3-methyl-2-butanol, and 2-methoxy-1-phenylethane-1-ol (also known as 2-methoxy-1-phenylethanol), which are preferably used. Among these, it is particularly preferable to include one or more selected from propylene glycol monomethyl ether (PGME) and 1-phenoxy-2-propanol from the viewpoint of polyamic acid solubility.

[0037] As will be shown in the comparative examples described later, when propylene glycol-1-monomethyl ether-2-acetate (PGMEA) is used as the organic solvent, the reactivity differs significantly from that when using an organic solvent containing an alcohol with an ether structure, even when synthesizing polyamic acid using the same type of starting monomer in that organic solvent. Although PGMEA is a compound with an ether structure, the reactivity and solubility of polyamic acid differ greatly. From this point of view, it can be said that there is a significant difference in the reactivity of the starting monomer diamine component and the tetracarboxylic dianhydride component in the organic solvent depending on the type of organic solvent.

[0038] Furthermore, the organic solvent may be a mixed solvent containing other types of organic solvents, as long as it does not impair the reactivity of the selected raw material monomers, and mainly contains the alcohol having the ether structure described above. The main component refers to a component that is present in a proportion of 51% by mass or more of the total amount of the organic solvent. In particular, the alcohol having the ether structure is preferably present in a proportion of 70% by mass or more, preferably 80% by mass or more, and more preferably 90% by mass or more of the total amount of the organic solvent. It is especially preferable that the entire amount of the organic solvent is alcohol having the ether structure.

[0039] Furthermore, it is preferable that the organic solvent does not contain amide-based solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DFM), N-methylpyrrolidone (NMP), or N-butyl-2-pyrrolidone (NBP).

[0040] [Polyamic acid] Polyamic acid is a reaction product obtained by a polyaddition reaction between a diamine component and a tetracarboxylic dianhydride component, which are the starting monomers. Polyamic acid is a precursor of polyimide, and polyimide is obtained by dehydration cyclization (imidization) of polyamic acid.

[0041] The polyamic acid contained in the polyamic acid solution according to this embodiment is obtained by a polyaddition reaction of raw material monomers in an organic solvent containing an alcohol having an ether structure, which is a specific organic solvent. Therefore, it becomes a polyamic acid solution in which the polyamic acid is dissolved in the organic solvent as is.

[0042] If the diamine component and the tetracarboxylic dianhydride component undergo a good polyaddition reaction in an organic solvent containing an alcohol with an ether structure, a polyamic acid of an appropriate molecular weight is produced in the organic solvent, resulting in a polyamic acid solution with appropriate viscosity in which the polyamic acid is uniformly dispersed. Such a polyamic acid solution has excellent coating properties for substrates (supports) made of metals, etc., and makes it possible to form a good polyimide film. On the other hand, if the polyaddition reaction between the diamine component and the tetracarboxylic dianhydride component in an organic solvent containing an alcohol with an ether structure is poor, polyamic acid will not be effectively produced, and the solution will be gel-like or slurry-like with solid matter from unreacted raw materials or reactants settling. In addition, due to poor reactivity, the viscosity may not increase, and a polyamic acid solution with appropriate viscosity may not be obtained.

[0043] Thus, the reactivity of the diamine component and the tetracarboxylic dianhydride component in an organic solvent containing an alcohol with an ether structure, or in other words, the selection of each compound of the diamine component and the tetracarboxylic dianhydride component to ensure a good polyaddition reaction, is crucial.

[0044] (Diamine component) The diamine component includes one or more selected from 1,3-bis(3-aminophenoxy)benzene (TPE-M), 2,2'-bis(trifluoromethyl)benzidine (TFMB), and 3,3'-diaminodiphenylsulfone (3,3-DDS). Research by the inventors has shown that using such a diamine component allows for a good polyaddition reaction with a tetracarboxylic dianhydride component in an ether-structured alcohol, which is a specific organic solvent, resulting in a polyamic acid solution with appropriate viscosity and excellent coating properties.

[0045] The diamine component may be used as a single compound, or as a combination of multiple compounds in any molar ratio.

[0046] The total content of 1,3-bis(3-aminophenoxy)benzene, 2,2'-bis(trifluoromethyl)benzidine, and 3,3'-diaminodiphenylsulfone is preferably 80 mol% or more, and more preferably 90 mol% or more, relative to the total amount of diamine components.

[0047] The diamine component may include diamines other than those described above, insofar as it achieves the effects of the present invention. Examples of diamines other than those described above that the diamine component may contain include aromatic diamines such as 2,4-diaminotoluene; aliphatic diamines such as 1,10-diaminodecane, 2-methyl-1,8-octanediamine, and dimer amine; and siloxanediamines.

[0048] The siloxanediamine is not particularly limited. Examples of polysiloxanediamines that can be used include PAM-E, KF-8010, X-22-161A, X-22-161B, and X-22-9409 (all manufactured by Shin-Etsu Silicone Co., Ltd.).

[0049] If the diamine component includes an aliphatic diamine and / or a siloxanediamine, it is preferable that the content of the aliphatic diamine and the siloxanediamine are each less than 5 mol% of the total amount of the diamine component. If the diamine component includes an aliphatic diamine, it is preferable that the content of the aliphatic diamine is greater than 0 mol% and less than 5 mol% of the total amount of the diamine component. If the diamine component includes a siloxanediamine, it is preferable that the content of the siloxanediamine is greater than 0 mol% and less than 5 mol% of the total amount of the diamine component. If the diamine component includes an aliphatic diamine and a siloxanediamine, it is sufficient that the content of the aliphatic diamine and the siloxanediamine are each less than 5 mol% of the total amount of the diamine component, and the combined content of the aliphatic diamine and the siloxanediamine may be greater than 0 mol% and less than 10 mol% of the total amount of the diamine component.

[0050] Furthermore, it is preferable that the diamine component does not contain aliphatic diamines. Aliphatic diamines not only have poor reactivity with tetracarboxylic dianhydride components in alcohols having an ether structure, but even if a polyamic acid is generated, the glass transition temperature (Tg) of the polyimide obtained by imidizing that polyamic acid may be low.

[0051] (Tetracarboxylic acid dianhydride component) The tetracarboxylic dianhydride components are not particularly limited. For example, 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), pyromellitic dianhydride (PMDA), 4,4'-oxydiphthalic anhydride (s-ODPA), 3,4'-oxydiphthalic anhydride (a-ODPA), 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic anhydride (BPADA), 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), norbornane-2-spiro-2'-cyclopentanone -5'-Spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid dianhydride (CpODA), 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic acid anhydride (6FDA), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2-dicarboxylic acid anhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, methylene-4,4'-diphthalic acid dianhydride, 1,1-ethylidene-4,4'-diphthalic acid di Anhydride, 2,2-propyridene-4,4'-diphthalic acid dianhydride, 1,2-ethylene-4,4'-diphthalic acid dianhydride, 1,3-trimethylene-4,4'-diphthalic acid dianhydride, 1,4-tetramethylene-4,4'-diphthalic acid dianhydride, 1,5-pentamethylene-4,4'-diphthalic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride, p-phenylenebis(trimellitate anhydride), thio-4,4'-diphthalic acid dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxypheno Xy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-Dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 2,3,6,7-anthracenetetracarboxylic acid dianhydride, 1,2,7,8-phenanthrenetetracarboxylic acid dianhydride, bicyclohexyl-3,3',9,9-bis(3,4-dicarboxyphenyl)fluorenediacid anhydride (BPAF), 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA) Examples include 2,2',3,3'-benzophenonetetracarboxylic dianhydride, spiro[11H-difluoro[3,4-b:3',4'-i]xanthene-11,9'-[9H]fluorene]-1,3,7,9-tetron (SFDA), (1,3-dioxoisobenzofuran-5-yl)1,3-dioxoisobenzofuran-5-carboxylate (8CI), bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-2,2',3,3',5,5'-hexamethylbiphenyl-4,4'-diyl (TAHMBP), etc.

[0052] Among these, the tetracarboxylic dianhydride component is preferably a compound having either a diphenyl ether group or a benzophenone group in its molecule. As will be shown in the examples described later, such tetracarboxylic dianhydride components exhibit particularly good reactivity in polyaddition reactions with the aforementioned diamine components in organic solvents containing alcohols having an ether structure.

[0053] Specifically, examples of tetracarboxylic dianhydrides having a diphenyl ether group in the molecule include 4,4'-oxydiphthalic anhydride (s-ODPA), 3,4'-oxydiphthalic anhydride (a-ODPA), 3,4'-oxydiphthalic dianhydride, 3,3'-oxydiphthalic dianhydride, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (BPADA), 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, and 1,4-bis(3,4-dicarboxyphenoxy Examples include benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane dianhydride, and 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane dianhydride.

[0054] Examples of tetracarboxylic dianhydrides having a benzophenone group in the molecule include 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) and 2,2',3,3'-benzophenonetetracarboxylic dianhydride.

[0055] Furthermore, the tetracarboxylic dianhydride component is more preferably one or more selected from 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 4,4'-oxydiphthalic acid anhydride (s-ODPA), and 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic acid anhydride (BPADA). The tetracarboxylic dianhydride component may also include one or more selected from 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), pyromellitic acid dianhydride (PMDA), and 3,4'-oxydiphthalic acid anhydride (a-ODPA).

[0056] The tetracarboxylic dianhydride component may be one of the above-mentioned compounds used alone, or multiple types may be used in any molar ratio. When multiple types are combined, preferably 80 mol% or more, more preferably 90% or more, of the total amount of tetracarboxylic dianhydride components are aromatic ring compounds.

[0057] (Molar ratio of diamine component to acid dianhydride) The molecular weight of the resulting polyamic acid can be adjusted by adjusting the ratio of the total number of moles of the diamine component to the total number of moles of the tetracarboxylic dianhydride component. Specifically, the number of moles of each component is not particularly limited, but it is preferable that they be approximately equimolar. In terms of the molar ratio expressed as acid dianhydride / diamine, it is preferable that it is greater than 0.9 and less than 1.2, more preferably between 0.95 and 1.1, and particularly preferably 1.

[0058] Thus, by ensuring that the total molar amount of the diamine component and the total molar amount of the tetracarboxylic dianhydride are approximately equimolar, it is possible to prevent a decrease in the molecular weight of the polyamic acid. Furthermore, it is possible to suppress the decrease in mechanical strength of the polyimide obtained by imidizing the polyamic acid. In addition, it prevents a decrease in the viscosity of the polyamic acid solution, resulting in even better coating properties. However, if the viscosity of the polyamic acid solution decreases, problems may occur, such as poor dispersibility of additives like inorganic fillers when dispersing them in the solution, leading to filler sedimentation.

[0059] (Synthesis of polyamic acid) The synthesis of polyamic acids by polyaddition of a diamine component and a tetracarboxylic dianhydride component is carried out in an organic solvent containing an alcohol having an ether structure. Furthermore, the polyaddition reaction is preferably carried out under an inert atmosphere such as argon or nitrogen.

[0060] Specifically, the polymerization reaction is carried out by dissolving the diamine component and the tetracarboxylic dianhydride component in an organic solvent containing an alcohol having an ether structure under an inert atmosphere, and then mixing them. The order in which the diamine component and the tetracarboxylic dianhydride component are added is not particularly limited. For example, the diamine component can be dissolved or dispersed in a slurry in an organic solvent to form a diamine solution, and then the tetracarboxylic dianhydride component can be added to the diamine solution to carry out the reaction. At this time, the tetracarboxylic dianhydride component may be added to the diamine solution in a solid state, or it may be dissolved or dispersed in an organic solvent containing an alcohol having an ether structure to form an acid dianhydride solution before being added.

[0061] The reaction temperature is not particularly limited. From the viewpoint of suppressing the decrease in molecular weight due to the depolymerization of the generated polyamic acid, the reaction temperature is preferably 80°C or lower. Furthermore, from the viewpoint of allowing the polymerization reaction to proceed appropriately, the reaction temperature is more preferably 10°C to 50°C. The reaction time can be set as appropriate, for example, in the range of 10 minutes to 30 hours.

[0062] (Molecular weight of polyamic acid) The weight-average molecular weight of the polyamic acid is not particularly limited, but is preferably in the range of 10,000 to 200,000, more preferably in the range of 30,000 to 180,000, and even more preferably in the range of 40,000 to 150,000. If the weight-average molecular weight is 10,000 or more, the mechanical strength of the polyimide obtained by imidizing the polyamic acid can be made sufficient. Furthermore, if the weight-average molecular weight of the polyamic acid is 200,000 or less, it exhibits sufficient solubility in organic solvents containing alcohols having an ether structure, making it easier to obtain a coating film with a smooth surface and uniform thickness on the substrate, as well as a polyimide film obtained by imidizing it.

[0063] Note that the molecular weight of the polyamic acid is the value obtained by gel filtration chromatography (GPC) on a polyethylene oxide basis.

[0064] [Additives] The polyamic acid solution may contain various additives, provided that these additives do not impair the solubility or storage stability of the polyamic acid in organic solvents. Examples of additives include inorganic fillers, imidation catalysts, dehydration catalysts, and surface modifiers. However, the additives are not limited to these.

[0065] Specifically, examples of inorganic fillers include inorganic salts such as aluminum oxide, silicon dioxide, calcium carbonate, and calcium phosphate. The shape of these inorganic fillers is not particularly limited and may be in powder, spherical, fibrous, or any other form.

[0066] Furthermore, tertiary amine compounds are preferably used as imidation catalysts, and heterocyclic tertiary amine compounds are particularly preferred among them. Examples include pyridine, 2,5-diethylpyridine, picoline, quinoline, isoquinoline, and 1,2-dimethylimidazole. Examples of dehydration catalysts include acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride.

[0067] Furthermore, adding an imidizing agent or dehydration catalyst to a polyamic acid solution may cause the imidation reaction to proceed, resulting in gelation. Therefore, it is preferable to dissolve the imidizing agent or dehydration catalyst in an organic solvent and mix the resulting solution with the polyamic acid solution. Additionally, from the viewpoint of improving the storage stability of the polyamic acid solution, the aforementioned imidizing catalyst or dehydration catalyst may be added immediately before coating the polyamic acid solution onto the substrate.

[0068] Furthermore, surface modifiers can be added for purposes such as defoaming the solution or improving the surface smoothness of the formed polyimide film. The surface modifier is not particularly limited, but any agent that has appropriate compatibility with polyamic acid and other materials, and also possesses defoaming properties, is acceptable. Examples include acrylic compounds and silicon compounds.

[0069] [Stability of polyamic acid solution] As described above, polyamic acids obtained by the polyaddition reaction of a specific diamine component with a tetracarboxylic dianhydride component exhibit excellent stability in organic solvents containing alcohols with an ether structure. In other words, polyamic acids have excellent solubility in organic solvents containing alcohols with an ether structure, and can suppress the occurrence of solidification and gelation over long periods of time.

[0070] Furthermore, the progression of imidization of polyamic acid in the polyamic acid solution can also be suppressed. Specifically, the imidization rate of polyamic acid is 30 mol% or less, preferably 10 mol% or less, relative to the total amount of structural units in the polyamic acid. Moreover, it is preferable that the imidization rate be even lower, and may be 1 mol% or less, or even 0 mol%. In this way, the imidization rate of polyamic acid in the polyamic acid solution is low, which suppresses viscosity increase, solidification, and gelation.

[0071] ≪2. Polyimides and Polyimide Films≫ By imidizing the polyamic acid contained in the polyamic acid solution described above, polyimide, an imidized product, can be obtained. Specifically, the polyamic acid solution is coated onto the surface of a substrate, and the organic solvent contained in the polyamic acid solution is evaporated by drying the coated film. Subsequently, or simultaneously, the polyamic acid is imidized by dehydration and ring closure to obtain a polyimide (polyimide film).

[0072] The resulting polyimide has a structure derived from a diamine and a structure derived from a tetracarboxylic dianhydride. Therefore, the polyimide obtained from the polyamic acid solution according to this embodiment has a diamine residue containing one or more selected from 1,3-bis(3-aminophenoxy)benzene (TPE-M), 2,2'-bis(trifluoromethyl)benzidine (TFMB), and 3,3'-diaminodiphenylsulfone (3,3-DDS).

[0073] The application of the polyamic acid solution to the substrate is not particularly limited and can be carried out by known methods such as gravure coating, spin coating, screen printing, dip coating, bar coating, knife coating, roll coating, and die coating.

[0074] The substrate (support) to which the polyamic acid solution is coated is not particularly limited. Examples include metal substrates containing metal bodies or metal compounds such as copper plates, aluminum plates, and stainless steel plates, glass substrates, silicon wafers, polyethylene terephthalate, polycarbonate, polyacrylate, and other film substrates.

[0075] The organic solvent in the coating film obtained by coating the substrate can be removed by volatilization by heating the coating film. The heating temperature should be set according to the type of alcohol containing an ether structure in the polyamic acid solution. Heating can be carried out under air, under reduced pressure, or under an inert gas such as nitrogen.

[0076] Dehydration and ring closure of polyamic acid can be performed by heating the polyamic acid. For example, a coating film containing polyamic acid applied to the surface of a substrate is heat-treated in the range of 80°C to 200°C.

[0077] The heating time is preferably set appropriately according to the amount of polyamic acid to be dehydrated and cyclized and the heating temperature, and generally, it is preferable to heat for a range of 1 minute to 5 hours after the processing temperature reaches the maximum temperature. In addition, the imidation of dehydration cyclization proceeds along with the heating for the volatilization of the organic solvent mentioned above.

[0078] Furthermore, as described above, in order to shorten the heating time and achieve the desired properties, additives such as imidizing agents and dehydration catalysts may be added to the polyamic acid solution, and the coating film made from the polyamic acid solution with such additives added may be heat-treated to imide it.

[0079] As the imidating agent, tertiary amine compounds are preferred, and heterocyclic tertiary amines are more preferred. Specifically, examples include pyridine, 2,5-diethylpyridine, picoline, quinoline, isoquinoline, and 1,2-dimethylimidazole. Specifically, examples of dehydration catalysts include acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride. The amount of imidating agent and dehydration catalyst added is preferably 0.05 to 5.0 times the molar equivalent of the imidating agent and more preferably 0.07 to 2.5 times the molar equivalent of the amide group of the polyamic acid. Furthermore, for the dehydration catalyst, it is preferably 0.5 to 10.0 times the molar equivalent of the amide group of the polyamic acid and more preferably 0.7 to 5.0 times the molar equivalent of the dehydration catalyst.

[0080] ≪3. Laminate comprising a polyimide film and method for manufacturing the same≫ As described above, a polyimide film, which is an imidized product, can be formed on the substrate by coating the surface of the substrate with a polyamic acid solution and heat-treating it to perform dehydration cyclization and imidization. This makes it possible to obtain a laminate having a substrate and a polyimide film on one or both sides of the substrate.

[0081] Therefore, a method for manufacturing a laminate can be defined as a method comprising the steps of: applying a polyamic acid solution to one or both sides of a substrate made of metal or the like to form a coating film containing polyamic acid; and heating the coating film to imide the polyamic acid to form a polyimide film.

[0082] The thickness of the polyimide film constituting the laminate can be appropriately set according to the application and desired function of the polyimide film, and is not particularly limited. For example, it can be about 1 μm to 50 μm, and is preferably about 5 μm to 30 μm. [Examples]

[0083] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the following examples.

[0084] [Production of polyamic acid solution (varnish)] An alcohol having an ether structure, which is an organic solvent, was placed in a separable flask and stirred under a nitrogen atmosphere. In Examples 1-13 and Comparative Examples 1-22 shown in Table 1, and Examples 21-40 shown in Table 4, propylene glycol monomethyl ether (PGME) was used. In Comparative Examples 23-51 shown in Table 2, propylene glycol-1-monomethyl ether-2-acetate (PGMEA) was used. In Examples 14-20 and Comparative Examples 52-62 shown in Table 3, 1-phenoxy-2-propanol was used.

[0085] The diamine component and the tetracarboxylic dianhydride component were added in the ratios (mol%) shown in Tables 1-4, and the mixture was stirred under a nitrogen atmosphere for 5-10 hours to react and obtain a solution containing polyamic acid with a solid content of 18% by mass.

[0086] [Compounds used in the production of polyamic acid solution and their abbreviations] (organic solvent) • Alcohols with an ether structure (alcohol-based solvents) Propylene glycol monomethyl ether (PGME) (Used in Examples 1-13 and Comparative Examples 1-22 in Table 1, and Examples 21-40 in Table 4) 1-Phenoxy-2-propanol (Used in Examples 14-20 and Comparative Examples 52-62 in Table 3) • Ester solvents Propylene glycol-1-monomethyl ether-2-acetate (PGMEA) (Used in Comparative Examples 23-51 in Table 2)

[0087] (Diamine component) 'BAPP': 2,2-bis[4-(4-aminophenoxy)phenyl]propane TPE-M: 1,3-bis(3-aminophenoxy)benzene TPE-R: 1,3-bis(4-aminophenoxy)benzene TFMB: 2,2'-bis(trifluoromethyl)benzidine 3,3-DDS: 3,3'-diaminodiphenylsulfone 'm-Tolidine': m-Tolidine '4,4-ODA': 4,4'-diaminodiphenyl ether 'm-PDA': m-phenylenediamine PDA: p-phenylenediamine '10DA': 1,10-diaminodecane KF-8010: Siloxanediamine

[0088] (Tetracarboxylic acid dianhydride component) 'BPADA': 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride 's-ODPA': 4,4'-oxydiphthalic anhydride 'a-ODPA': 3,4'-oxydiphthalic anhydride BTDA: 3,3',4,4'-benzophenonetetracarboxylic dianhydride 'a-BPDA': 2,3,3',4'-biphenyltetracarboxylic acid dianhydride 's-BPDA': 3,3',4,4'-biphenyltetracarboxylic acid dianhydride PMDA: Pyromellitic anhydride Of the compounds used as tetracarboxylic dianhydride components mentioned above, BPADA and ODPA are compounds that have a diphenyl ether group in their molecules. BTDA, on the other hand, is a compound that has a benzophenone group in its molecule.

[0089] [evaluation] (Regarding the reactivity of polyamic acid synthesis in organic solvents) For the obtained polyamic acid solution, the molecular weight of the polyamic acid in the solution was measured. If the molecular weight was 10,000 or more, it was evaluated as '◎' or '○', indicating that the diamine component and the tetracarboxylic dianhydride component had reacted well. Furthermore, if it was visually confirmed that the viscosity of the solution did not increase further after 1 hour from the mixing of the diamine component and the tetracarboxylic dianhydride component (i.e., the reaction was very fast and reached a near-steady state in 1 hour), it was evaluated as '◎'. If it took more than 1 hour from the start of mixing to reach a steady state (i.e., the reaction was fast), it was evaluated as '○'. The molecular weight of the polyamic acid was measured using gel filtration chromatography (GPC) and is the weight-average molecular weight (Mw) in terms of polyethylene oxide.

[0090] On the other hand, if no increase in viscosity was observed, or if gelation occurred while some powder remained, visual inspection indicated that the diamine component and tetracarboxylic dianhydride component remained intact, and the molecular weight of the polyamic acid was considered to be less than 10,000, resulting in a reactivity rating of '×'.

[0091] (Molecular weight of polyamic acid) In addition, the evaluation column in each table also shows the measured weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the obtained polyamic acid. As mentioned above, the molecular weight of the polyamic acid is the polyethylene oxide equivalent value measured using gel filtration chromatography (GPC). In Tables 1 to 4, a "-" in the molecular weight measurement results indicates that the measurement was not performed.

[0092] [result] Tables 1-4 below show the raw material monomers used and the results of the reactivity of polyamic acid synthesis in organic solvents. As mentioned above, Tables 1 and 4 show the test results using propylene glycol monomethyl ether (PGME) as the organic solvent, Table 2 shows the test results using propylene glycol-1-monomethyl ether-2-acetate (PGMEA) as the organic solvent, and Table 3 shows the test results using 1-phenoxy-2-propanol as the organic solvent.

[0093] [Table 1]

[0094] [Table 2]

[0095] [Table 3]

[0096] [Table 4]

[0097] The results shown in Tables 1-4 indicate that the reactivity of the polyaddition reaction between the diamine component and the tetracarboxylic dianhydride component varies significantly depending on the type of organic solvent used in the synthesis of polyamic acids. Furthermore, even when using the same organic solvent, the reactivity of the polyaddition reaction differs depending on the specific compound species, i.e., combination, of the diamine component and the tetracarboxylic dianhydride component.

[0098] As can be seen from the results shown in Tables 1 and 3, when an alcohol with an ether structure was used as the organic solvent, the diamine component containing one or more selected from 1,3-bis(3-aminophenoxy)benzene (TPE-M), 2,2'-bis(trifluoromethyl)benzidine (TFMB), and 3,3'-diaminodiphenylsulfone (3,3-DDS) reacted well with the tetracarboxylic dianhydride component through polyaddition, yielding a varnish with appropriate viscosity. Table 2 shows that when PGMEA, which is not an alcohol with an ether structure, was used as the organic solvent, even when the same diamine component as the above-mentioned compounds was used, a good polyaddition reaction did not occur, there was no appropriate increase in viscosity, and the result was poor, including gelation.

Claims

1. A polyamic acid composition comprising an organic solvent and a polyamic acid which is a polyaddition reaction product of a diamine component and a tetracarboxylic dianhydride component in the organic solvent, The organic solvent comprises an alcohol having an ether structure. The diamine component comprises one or more selected from 1,3-bis(3-aminophenoxy)benzene, 2,2'-bis(trifluoromethyl)benzidine, and 3,3'-diaminodiphenylsulfone. Polyamic acid composition.

2. The total content of 1,3-bis(3-aminophenoxy)benzene, 2,2'-bis(trifluoromethyl)benzidine, and 3,3'-diaminodiphenylsulfone is 80 mol% or more of the total amount of the diamine component. The polyamic acid composition according to claim 1.

3. The tetracarboxylic dianhydride component includes a compound having either a diphenyl ether group or a benzophenone group in its molecule. The polyamic acid composition according to claim 1.

4. The tetracarboxylic dianhydride component comprises one or more selected from 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, and 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride. The polyamic acid composition according to claim 1.

5. The tetracarboxylic dianhydride component comprises one or more selected from 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, and 3,4'-oxydiphthalic anhydride. The polyamic acid composition according to claim 1.

6. If the diamine component includes an aliphatic diamine and / or a siloxanediamine, The content of the aliphatic diamine and the siloxane diamine is less than 5 mol% of the total amount of the diamine component. The polyamic acid composition according to claim 1.

7. The content of the alcohol having the ether structure is 70% by mass or more relative to the total amount of the organic solvent. The polyamic acid composition according to claim 1.

8. The organic solvent comprises one or more selected from propylene glycol monomethyl ether (PGME) and 1-phenoxy-2-propanol. The polyamic acid composition according to claim 1.

9. A method for producing a polyamic acid composition containing a polyamic acid obtained by polyaddition reaction of a diamine component and a tetracarboxylic dianhydride component in an organic solvent, In an organic solvent containing an alcohol having an ether structure, A diamine component containing one or more selected from 1,3-bis(3-aminophenoxy)benzene, 2,2'-bis(trifluoromethyl)benzidine, and 3,3'-diaminodiphenylsulfone is mixed with a tetracarboxylic dianhydride component. A method for producing a polyamic acid composition.

10. A polyimide that is an imide of a polyamic acid contained in the polyamic acid composition according to any one of claims 1 to 8.

11. A polyimide film comprising the polyimide described in claim 10.

12. A laminate comprising a base material and a polyimide film according to claim 11 formed on one or both sides of the base material.

13. A method for manufacturing a laminate comprising a substrate and a polyimide film, A step of coating one or both sides of the substrate with the polyamic acid composition according to any one of claims 1 to 8 to form a coating film containing the polyamic acid, The process includes a step of heating the coating film to imide the polyamic acid and form a polyimide film. A method for manufacturing laminates.

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