TWI893196B - Polyamic acid composition, polyimide, polyimide film, laminate, method for manufacturing laminate, and electronic device - Google Patents

Abstract

The polyamic acid composition of the present invention contains a polyamic acid containing a structural unit represented by the following general formula (1) and a plasticizer. The polyimide of the present invention is an imide compound of a polyamic acid containing a structural unit represented by the following general formula (1). The polyimide film of the present invention contains an imide compound of a polyamic acid containing a structural unit represented by the following general formula (1). The laminate of the present invention has a support; and a polyimide film containing an imide compound of a polyamic acid containing a structural unit represented by the following general formula (1). The electronic device of the present invention comprises: a polyimide film containing an imide compound of polyamic acid comprising a structural unit represented by the following general formula (1); and an electronic element disposed on the polyimide film.

Description

Polyamic acid composition, polyimide, polyimide film, laminate, method for manufacturing laminate, and electronic device

The present invention relates to a polyamide composition, polyimide, polyimide film, laminate, method for manufacturing the laminate, and electronic device. The present invention further relates to electronic device materials using polyimide, thin-film transistor (TFT) substrates, flexible display substrates, color filters, printed materials, optical materials, image display devices (more specifically, liquid crystal displays, organic EL (electroluminescence), electronic paper, etc.), 3D displays, solar cells, touch panels, transparent conductive film substrates, and alternative materials to components currently using glass.

With the rapid development of displays such as liquid crystal displays (LCDs), organic EL displays (EL), and electronic paper, as well as electronic devices such as solar cells and touch panels, the trend toward thinner, lighter, and more flexible devices continues. In these devices, polyimide is being used as a substrate material instead of glass.

In these devices, various electronic components, such as thin-film transistors and transparent electrodes, are formed on substrates. The formation of these electronic components requires high-temperature processes. Polyimide has sufficient heat resistance to withstand these high-temperature processes, and its coefficient of thermal expansion (CTE) is close to that of glass substrates and electronic components. Therefore, it is less likely to generate internal stress, making it suitable as a substrate material for flexible displays, etc.

Generally speaking, aromatic polyimides produce a yellow-brown color due to the formation of intramolecular conjugation or charge transfer (CT) complexes. However, in top-emission organic EL displays, light is extracted from the opposite side of the substrate, so substrate transparency is not required, and conventional aromatic polyimides have been used. However, in applications such as transparent displays, bottom-emission organic EL displays, and liquid crystal displays, where light emitted from the display element passes through the substrate, or where sensors or camera modules are placed on the back of the substrate to achieve full-screen (notchless) displays such as smartphones, the substrate is required to have higher optical properties (more specifically, transparency).

Against this backdrop, there is a need for a material that has heat resistance comparable to existing aromatic polyimides, while exhibiting reduced coloration and superior transparency.

There are known technologies for reducing the coloration of polyimide by using aliphatic monomers to suppress the formation of CT complexes (Patent Documents 1 and 2), and for improving transparency by using monomers having fluorine or sulfur atoms (Patent Document 3).

While the polyimides described in Patent Documents 1 and 2 have high transparency and a low CTE, their aliphatic structure results in a low thermal decomposition temperature, making them difficult to use in high-temperature processes used to form electronic components. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Publication No. 2016-29177 [Patent Document 2] Japanese Patent Publication No. 2012-41530 [Patent Document 3] Japanese Patent Publication No. 2014-70139

[Identify the problem you want to solve]

The polyimide described in Patent Document 3 contains fluorine atoms, and therefore may generate hydrogen fluoride during high-temperature processing. Research by the present inventors has revealed that this generation of hydrogen fluoride can lead to poor adhesion between the polyimide and barrier films, or can cause corrosion of electronic devices mounted on the polyimide film.

The present invention was completed in light of the above-mentioned practical situation. Its purpose is to provide a polyimide and a polyamide composition serving as a precursor thereof that exhibit reduced coloration, excellent transparency, high heat resistance, and the ability to suppress the generation of hydrogen fluoride during high-temperature processes. Furthermore, the present invention also aims to provide a product or component requiring heat resistance and transparency that can be manufactured using the polyimide and polyamide composition. In particular, the present invention aims to provide a product or component having a polyimide film of the present invention formed on the surface of an inorganic material such as glass, metal, metal oxide, or single-crystal silicon. [Technical Means for Solving the Problem]

The inventors of the present invention have conducted intensive research and discovered that polyimide obtained from a composition containing a specific polyamide and a plasticizer exhibits reduced coloration, excellent transparency, high heat resistance, and the ability to suppress the generation of hydrogen fluoride during high-temperature processing. This led to the completion of the present invention.

The polyamine composition of the present invention contains polyamine comprising a structural unit represented by the following general formula (1) and a plasticizer.

[Chemistry 1]

In the above general formula (1), ^R1 and ^R2 each independently represent a hydrogen atom, a monovalent aliphatic group or a monovalent aromatic group, and X represents a tetravalent organic group.

In the polyamine composition of one embodiment of the present invention, R ¹ and R ² in the above general formula (1) both represent hydrogen atoms.

In the polyamino acid composition of one embodiment of the present invention, X in the above-mentioned general formula (1) is one or more selected from the group consisting of a tetravalent organic group represented by the following chemical formula (2), a tetravalent organic group represented by the following chemical formula (3), a tetravalent organic group represented by the following chemical formula (4), and a tetravalent organic group represented by the following chemical formula (5).

[Chemistry 2]

In the polyamine composition according to one embodiment of the present invention, the content of the structural unit represented by the general formula (1) is 50 mol% to 100 mol% relative to all structural units of the polyamine.

In the polyamine composition according to one embodiment of the present invention, the amount of the plasticizer is 20 parts by weight or less relative to 100 parts by weight of the polyamine.

In the polyamic acid composition of one embodiment of the present invention, the plasticizer is at least one selected from the group consisting of phosphorus-containing compounds, polyalkylene glycols, and aliphatic dibasic acid esters.

In one embodiment of the present invention, the polyamine composition further contains an organic solvent.

The polyimide of the present invention is an imide of the polyamic acid contained in the polyamic acid composition of the present invention.

The 1% weight loss temperature of the polyimide of the present invention is preferably above 500°C.

The polyimide film of the present invention comprises the polyimide of the present invention.

The yellowness of the polyimide film of the present invention is preferably 20 or less.

The laminate of the present invention comprises a support and the polyimide film of the present invention.

The method for producing the laminate of the present invention comprises coating the polyamide composition of one embodiment of the present invention on a support to form a coating film comprising polyamide and a plasticizer, and heating the coating film to imidize the polyamide.

The electronic device of the present invention comprises the polyimide film of the present invention and an electronic component disposed on the polyimide film. [Effects of the Invention]

Polyimides produced using the polyamic acid composition of the present invention exhibit reduced coloration, excellent transparency and heat resistance, and can suppress the generation of hydrogen fluoride during high-temperature processing. Therefore, polyimides produced using the polyamic acid composition of the present invention are suitable for use as materials in electronic devices that require low coloration, transparency, and heat resistance and must be manufactured through high-temperature processes.

Hereinafter, preferred embodiments of the present invention are described in detail, but the present invention is not limited thereto.

First, the terms used in this specification are explained. "Structural unit" refers to a repeating unit that constitutes a polymer. "Polyamide" is a polymer containing a structural unit represented by the following general formula (6) (hereinafter sometimes described as "structural unit (6)"). Furthermore, in this specification, in addition to polyamide, polyamide esters (polyamide alkyl esters, polyamide aryl esters, etc.) are also described as "polyamide".

[Chemistry 3]

In general formula (6), ^R3 and ^R4 each independently represent a hydrogen atom, a monovalent aliphatic group, or a monovalent aromatic group; ^A1 represents, for example, a tetracarboxylic dianhydride residue (a tetravalent organic group derived from tetracarboxylic dianhydride); and ^A2 represents, for example, a diamine residue (a divalent organic group derived from diamine).

The content of the structural unit (6) relative to all the structural units constituting the polyamide is, for example, 50 mol% to 100 mol%, preferably 60 mol% to 100 mol%, more preferably 70 mol% to 100 mol%, further preferably 80 mol% to 100 mol%, further preferably 90 mol% to 100 mol%, and can also be 100 mol%.

The "1% weight loss temperature" refers to the temperature at which the weight of the polyimide decreases by 1% relative to the weight of the polyimide at a measurement temperature of 150°C (100% by weight). The 1% weight loss temperature is determined by the same method as in the following examples or by reference to the method in the following examples.

"m/z" is a measured value that can be read from the horizontal axis of a mass spectrum obtained as a result of mass analysis. It refers to "the dimensionless quantity obtained by dividing the mass of an ion by the unified atomic mass unit (Dalton) and further dividing it by the absolute value of the ion's charge."

"Plasticizer" refers to a material that is present in liquid form when at least a portion of the polyamide is imidized.

Hereinafter, "" will sometimes be appended after a compound name to collectively refer to the compound and its derivatives. When "" is appended after a compound name to represent a polymer, it means that the repeating units of the polymer are derived from the compound or its derivatives. Furthermore, tetracarboxylic dianhydride is sometimes referred to as "acid dianhydride."

The polyamine composition of this embodiment contains a polyamine comprising a structural unit represented by the following general formula (1) (hereinafter sometimes referred to as "structural unit (1)") and a plasticizer.

[Chemistry 4]

In general formula (1), ^R1 and ^R2 each independently represent a hydrogen atom, a monovalent aliphatic group, or a monovalent aromatic group, and X represents a tetravalent organic group. To facilitate imidization, ^R1 and ^R2 each independently represent preferably a hydrogen atom, a methyl group, or an ethyl group, and ^R1 and ^R2 both preferably represent a hydrogen atom. Hereinafter, unless otherwise specified, a structural unit in which ^R1 and ^R2 in general formula (1) both represent a hydrogen atom is referred to as structural unit (1).

The polyamide composition of the present embodiment contains polyamide comprising the structural unit (1) and a plasticizer. Therefore, if the polyamide composition of the present embodiment is used to produce polyimide, a polyimide with reduced coloration, excellent transparency and heat resistance, and the ability to suppress the generation of hydrogen fluoride during a high-temperature process can be obtained.

The structural unit (1) has a partial structure derived from 2,2'-bis(trifluoromethyl)benzidine (hereinafter sometimes referred to as "TFMB"). That is, the structural unit (1) has a TFMB residue as A ² in the above general formula (6).

TFMB has a rigid structure and is suitable as a raw material (monomer) for polyimides with a high glass transition temperature (excellent heat resistance). Furthermore, because TFMB contains a trifluoromethyl group, it is suitable as a raw material (monomer) for polyimides with reduced coloration and high transparency.

When synthesizing a polyamine containing the structural unit (1) (hereinafter, sometimes referred to as "polyamine (1)"), diamines other than TFMB can be used as monomers within a range that does not impair its performance. Examples of diamines other than TFMB include 4-aminophenyl 4-aminobenzoate (hereinafter, sometimes referred to as "4-BAAB"), 1,4-cyclohexanediamine, p-phenylenediamine, m-phenylenediamine, 9,9-bis(4-aminophenyl)fluorene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether, 4,4'-diaminobenzanilide, N,N'-bis(4-aminophenyl) p-Tylene diamine, 4,4'-diaminodiphenylsulfone, m-tolidine, o-tolidine, 4,4'-bis(4-aminophenoxy)biphenyl, 2-(4-aminophenyl)-6-aminobenzoxazole, 3,5-diaminobenzoic acid, 4,4'-diamino-3,3'-dihydroxybiphenyl, 4,4'-methylenebis(cyclohexylamine), 1,3-bis(3-aminopropyl)tetramethyldisiloxane, and derivatives thereof may be used alone or in combination of two or more.

From the perspective of improving heat resistance, 4-BAAB is preferred as a diamine other than TFMB. Therefore, from the perspective of improving heat resistance, polyamide (1) preferably has a 4-BAAB residue. 4-BAAB has a rigid structure and is therefore suitable as a raw material (monomer) for polyimide having excellent heat resistance. Furthermore, 4-BAAB having a rigid structure is also suitable as a raw material (monomer) for polyimide having high mechanical strength and suppressing the generation of internal stress.

In order to obtain a polyimide with further reduced coloration, better heat resistance and higher transparency, the polyimide (1) preferably has only TFMB residues as diamine residues, or only TFMB residues and 4-BAAB residues as diamine residues.

In order to obtain a polyimide with further reduced coloration and better heat resistance, the content of TFMB residues relative to all diamine residues constituting the polyimide (1) is preferably 30 mol% or more, more preferably 40 mol% or more, further preferably 50 mol% or more, further preferably 60 mol% or more, and can also be 70 mol% or more, 80 mol% or more, or 90 mol% or more, and can also be 100 mol%.

In order to obtain a polyimide with further reduced coloration and better heat resistance, the content of the structural unit (1) relative to all the structural units of the polyamide (1) is preferably 30 mol% to 100 mol%, more preferably 40 mol% to 100 mol%, further preferably 50 mol% to 100 mol%, further preferably 60 mol% to 100 mol%, and can also be 70 mol% to 100 mol%, 80 mol% to 100 mol%, or 90 mol% to 100 mol%, and can also be 100 mol%.

When the polyamine (1) contains 4-BAAB residues, in order to obtain a polyimide having better heat resistance, the content of 4-BAAB residues relative to all diamine residues constituting the polyamine (1) is preferably 10 mol% or more, more preferably 20 mol% or more, and further preferably 30 mol% or more. Furthermore, when the polyamine (1) contains 4-BAAB residues, in order to obtain a polyimide having further reduced coloration, the content of 4-BAAB residues relative to all diamine residues constituting the polyamine (1) is preferably 70 mol% or less, more preferably 60 mol% or less, further preferably 50 mol% or less, and further preferably 40 mol% or less.

In the case where the polyamide (1) has TFMB residues and 4-BAAB residues, in order to obtain a polyimide with further reduced coloration, better heat resistance and higher transparency, the total content of TFMB residues and 4-BAAB residues relative to all diamine residues constituting the polyamide (1) is preferably 50 mol% or more, more preferably 60 mol% or more, further preferably 70 mol% or more, further preferably 80 mol% or more, and can also be 90 mol% or more, and can also be 100 mol%.

Examples of the tetracarboxylic dianhydride (the acid dianhydride providing X in the general formula (1)) used to synthesize the polyamine (1) include pyromellitic dianhydride (hereinafter, sometimes referred to as "PMDA"), 3,3',4,4'-biphenyltetracarboxylic dianhydride (hereinafter, sometimes referred to as "BPDA"), p-phenylene bis(trimellitic anhydride), 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, Dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (hereinafter sometimes referred to as "BPAF"), 4,4'-oxydiphthalic anhydride (hereinafter sometimes referred to as "ODPA"), 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 9,9-bis(trifluoromethyl)phthalate Tetracarboxylic dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2'-oxodispiro[bicyclo[2.2.1]heptane-2,1'-cyclopentane-3',2''-bicyclo[2.2.1]heptane]-5,6:5'',6''-tetracarboxylic dianhydride, and derivatives thereof may be used alone or in combination of two or more.

In order to obtain a polyimide that can further suppress the generation of hydrogen fluoride during a high-temperature process, the acid dianhydride providing X in the general formula (1) is preferably an acid dianhydride that does not contain a fluorine atom. In other words, in order to obtain a polyimide that can further suppress the generation of hydrogen fluoride during a high-temperature process, the acid dianhydride residue constituting the polyamide (1) preferably does not contain a fluorine atom.

The acid dianhydride providing X in the general formula (1) is preferably one or more selected from the group consisting of PMDA, BPDA, BPAF, and ODPA. In other words, the polyamic acid (1) preferably has one or more selected from the group consisting of PMDA residues, BPDA residues, BPAF residues, and ODPA residues as X in the general formula (1).

The PMDA residue is a tetravalent organic group represented by the following chemical formula (2). The BPDA residue is a tetravalent organic group represented by the following chemical formula (3). The BPAF residue is a tetravalent organic group represented by the following chemical formula (4). The ODPA residue is a tetravalent organic group represented by the following chemical formula (5).

[Chemistry 5]

In order to obtain a polyimide having better heat resistance, reduced internal stress, and high mechanical strength, the polyamide (1) preferably has at least one selected from the group consisting of PMDA residues and BPDA residues. In order to obtain a polyimide having higher transparency, the polyamide (1) preferably has at least one selected from the group consisting of BPAF residues and ODPA residues.

When the polyamine (1) has one or more residues selected from the group consisting of PMDA residues, BPDA residues, BPAF residues and ODPA residues, the total content of the PMDA residues, BPDA residues, BPAF residues and ODPA residues relative to all the acid dianhydride residues constituting the polyamine (1) is preferably 60 mol% or more, more preferably 70 mol% or more, further preferably 80 mol% or more, further preferably 90 mol% or more, and may be 100 mol%. When the total content of PMDA residues, BPDA residues, BPAF residues and ODPA residues relative to all the dianhydride residues constituting the polyimide (1) is 60 mol% or more, a polyimide having better transparency and heat resistance, reduced internal stress and high mechanical strength can be obtained.

In the case where the polyamide (1) has PMDA residues, in order to obtain a polyimide having better heat resistance, reduced internal stress, and high mechanical strength, the content of PMDA residues relative to all the acid dianhydride residues constituting the polyamide (1) is preferably 30 mol% to 100 mol%, more preferably 40 mol% to 90 mol%, and even more preferably 50 mol% to 80 mol%.

When the polyamide (1) has BPDA residues, in order to obtain a polyimide having better heat resistance, reduced internal stress, and high mechanical strength, the content of BPDA residues relative to all the acid dianhydride residues constituting the polyamide (1) is preferably not less than 10 mol% and not more than 100 mol%, and more preferably not less than 10 mol% and not more than 90 mol%.

When the polyamic acid (1) contains BPAF residues, in order to obtain a polyimide with higher transparency, the content of BPAF residues is preferably 1 mol% or more, more preferably 3 mol% or more, further preferably 5 mol% or more, and may be 10 mol% or more, relative to the total acid dianhydride residues constituting the polyamic acid (1). Furthermore, when the polyamic acid (1) contains BPAF residues, in order to reduce internal stress, the content of BPAF residues is preferably 50 mol% or less, more preferably 40 mol% or less, and further preferably 30 mol% or less, relative to the total acid dianhydride residues constituting the polyamic acid (1).

When the polyamide (1) has ODPA residues, in order to obtain a polyimide with higher transparency, the content of ODPA residues is preferably 1 mol% or more, more preferably 3 mol% or more, and further preferably 5 mol% or more relative to the total acid dianhydride residues constituting the polyamide (1). Furthermore, when the polyamide (1) has ODPA residues, in order to reduce internal stress, the content of ODPA residues is preferably 50 mol% or less, more preferably 40 mol% or less, and further preferably 30 mol% or less relative to the total acid dianhydride residues constituting the polyamide (1).

Polyamine (1) can be synthesized by a known general method, for example, by reacting a diamine with a tetracarboxylic dianhydride in an organic solvent. An example of a specific method for synthesizing polyamine (1) is described below. First, in an atmosphere of an inert gas such as argon or nitrogen, a diamine is dissolved or dispersed in an organic solvent in a slurry form to prepare a diamine solution. Then, tetracarboxylic dianhydride, either dissolved or dispersed in an organic solvent in a slurry form, or in a solid state, is added to the diamine solution.

When polyamic acid (1) is synthesized using diamine and tetracarboxylic dianhydride, the desired polyamic acid (1) (polymer of diamine and tetracarboxylic dianhydride) can be obtained by adjusting the amount of diamine (when multiple diamines are used, the amount of each diamine) and the amount of tetracarboxylic dianhydride (when multiple tetracarboxylic dianhydrides are used, the amount of each tetracarboxylic dianhydride). The molar fraction of each residue in polyamic acid (1) is consistent with the molar fraction of each monomer (diamine and tetracarboxylic dianhydride) used in the synthesis of polyamic acid (1). In addition, by blending two types of polyamic acid, polyamic acid (1) containing multiple tetracarboxylic dianhydride residues and multiple diamine residues can also be obtained. The temperature conditions for the reaction of diamine and tetracarboxylic dianhydride, i.e., the synthesis reaction of polyamine (1), are not particularly limited, and are, for example, in the range of 20° C. to 150° C. The reaction time for the synthesis reaction of polyamine (1) is, for example, in the range of 10 minutes to 30 hours.

The organic solvent used in the synthesis of polyamine (1) is preferably a solvent that can dissolve the tetracarboxylic dianhydride and diamine used, and more preferably a solvent that can dissolve the polyamine (1) to be produced. Examples of the organic solvent used in the synthesis of polyamine (1) include: urea-based solvents such as tetramethylurea and N,N-dimethylethylurea; sulfonium-based solvents such as dimethylsulfoxide; sulfonium-based solvents such as diphenylsulfoxide and tetramethylsulfoxide; N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP); ), amide solvents such as hexamethylphosphotriamide; ester solvents such as γ-butyrolactone; halogenated alkyl solvents such as chloroform and dichloromethane; aromatic hydrocarbon solvents such as benzene and toluene; phenolic solvents such as phenol and cresol; ketone solvents such as cyclopentanone; and ether solvents such as tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, dimethyl ether, diethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, and p-cresol methyl ether. These solvents are usually used alone, but may be used in combination of two or more as needed. In order to improve the solubility and reactivity of polyamine (1), the organic solvent used in the synthesis reaction of polyamine (1) is preferably one or more solvents selected from the group consisting of amide solvents, ketone solvents, ester solvents, and ether solvents, and more preferably an amide solvent (more specifically, DMF, DMAC, NMP, etc.). In addition, the synthesis reaction of polyamine (1) is preferably carried out under an inert gas atmosphere such as argon or nitrogen.

The weight average molecular weight of polyamine (1) is preferably in the range of 10,000 to 1,000,000, more preferably in the range of 20,000 to 500,000, and even more preferably in the range of 30,000 to 200,000, but this depends on its application. If the weight average molecular weight is 10,000 or more, it is easy to make polyamine (1) or polyimide obtained using polyamine (1) into a coating film or polyimide film (membrane). On the other hand, if the weight average molecular weight is 1,000,000 or less, it exhibits sufficient solubility in solvents, so that a coating film or polyimide film with a smooth surface and uniform thickness can be obtained using the following polyamine composition. The weight average molecular weight used here refers to the polyethylene oxide equivalent value measured by gel permeation chromatography (GPC).

Furthermore, as a method for controlling the molecular weight of polyamide (1), there can be cited a method of making either one of the acid dianhydride and the diamine excessive, or a method of quenching the reaction by reacting with a monofunctional acid anhydride or amine such as phthalic anhydride or aniline. In the case of carrying out polymerization by making either one of the acid dianhydride and the diamine excessive, if the feeding molar ratio thereof is between 0.95 and 1.05, a polyimide film having sufficient strength can be obtained. Furthermore, the above-mentioned feeding molar ratio is the ratio of the total amount of diamines used in the synthesis of polyamide (1) to the total amount of acid dianhydrides used in the synthesis of polyamide (1) (total amount of diamines/total amount of acid dianhydrides). Furthermore, by using phthalic anhydride, maleic anhydride, aniline, etc. for end-capping, the coloration of the polyimide obtained using polyamide (1) can be further reduced.

Next, the effects of the plasticizer (hereinafter sometimes simply referred to as "plasticizer") included in the polyamide composition of this embodiment will be described. Generally speaking, to obtain a transparent polyimide film, theoretically, it is sufficient to design a polyimide with a large band gap between the HOMO (Highest Occupied Molecular Orbital) and the LUMO (Lower Unoccupied Molecular Orbital). Therefore, to achieve a transparent polyimide film, a low-electron-donating TFMB is more effective. On the other hand, a low-electron-donating TFMB, due to its reduced nucleophilicity, is expected to have a slower reaction rate and a slower imidization rate. The present inventors have studied the imidization rate and have obtained the following findings. Specifically, a comparison of the imidization rates of a typical colored polyimide obtained from BPDA and p-phenylenediamine and a transparent polyimide obtained from PMDA or BPDA and TFMB revealed that the colored polyimide was imidized to over 90% at an imidization reaction temperature of 300°C and nearly 100% at an imidization reaction temperature of 350°C. However, the transparent polyimide was imidized to only approximately 75% at 300°C and 80% at 350°C, with no significant difference in the imidization rates.

Generally speaking, the driving force for the dehydration and ring closure of polyamides to form polyimides via thermal imidization is significantly influenced by molecular mobility caused by heat and the plasticization effect of the solvent. To achieve complete imidization, treatment should ideally be performed above the glass transition temperature (GTT) of the polyimide. However, when combining rigid acid dianhydrides such as PMDA with TFMB, the GTT of the resulting polyimide can sometimes exceed 400°C, which is higher than the heat treatment temperature for film formation. Consequently, there is a risk of incomplete imidization during the imidization reaction of rigid acid dianhydrides such as PMDA with TFMB. Therefore, in a high-temperature process using a polyimide film (e.g., annealing treatment of a TFT), unreacted sites in the polyimide film may undergo imidization, generating low-molecular-weight components from the imide film and generating outgassing (e.g., hydrogen fluoride), thereby causing peeling of the barrier film or corrosion of the TFT. In contrast, the polyamic acid composition according to the present embodiment, by using a plasticizer, provides sufficient molecular mobility during the imidization of the polyamic acid (1), not only allowing the imidization to proceed completely, but also suppressing the depolymerization of the polyamic acid (1), thereby suppressing the generation of outgassing (especially hydrogen fluoride). Furthermore, the polyamide composition according to this embodiment can easily remove the solvent by imparting molecular mobility to the polyamide (1), thereby reducing the amount of residual solvent in the film (polyimide film) and reducing the coloring of the film.

The inventors have conducted research and have discovered that by performing imidization in the presence of a plasticizer, the amount of residual solvent in the film can be reduced, significantly reducing outgassing itself. In particular, they have discovered that when using TFMB as a monomer, performing imidization in the presence of a plasticizer can suppress the generation of hydrogen fluoride gas when the resulting polyimide is used in a high-temperature process. The polyamide composition of this embodiment contains a plasticizer, thereby suppressing the generation of hydrogen fluoride during high-temperature processes. Therefore, the polyamic acid composition according to the present embodiment can suppress the corrosion of the barrier film formed on the polyimide film or the glass serving as the supporting substrate during the manufacturing process of a flexible display, thereby improving the reliability of the flexible display (the difficulty in causing failures). In addition, the polyamic acid composition according to the present embodiment can provide sufficient molecular mobility during the imidization of the polyamic acid (1) by using a plasticizer, thereby promoting imidization and obtaining a polyimide with excellent heat resistance. Furthermore, the plasticizer can remain in the polyimide film or be decomposed during the imidization process and removed from the polyimide film. When plasticizer remains in the polyimide film, in order to obtain a polyimide film with better heat resistance, the content of the plasticizer relative to the total weight of the polyimide film is preferably 0.01 wt % or less, more preferably 0.001 wt % or less, and even more preferably 0.0001 wt % or less.

Furthermore, the polyamide composition of this embodiment contains a plasticizer. Therefore, even if the TFMB residue content is high (e.g., even if it is 50 mol% or more relative to all diamine residues), the generation of hydrogen fluoride can be suppressed when the obtained polyimide is used in a high-temperature process.

As an indicator of the amount of hydrogen fluoride gas generated when using the imide compound of polyamide (1) (the polyimide of the present embodiment) in a high-temperature process, the detection intensity obtained by mass spectrometry can be cited. Specifically, the polyimide is first heated at a temperature of 10°C/min from an ambient temperature of 60°C under a helium flow. When the ambient temperature reaches 470°C, the gas generated from the polyimide is analyzed using a quadrupole mass spectrometer. Next, the intensity of the peak at m/z = 20, presumably due to hydrogen fluoride (hereinafter sometimes referred to as "peak intensity at m/z 20"), was read from the obtained mass spectrum (specifically, the mass spectrum obtained by analyzing the components of the gas generated from the polyimide at an atmosphere temperature of 470°C). A trend was observed where the intensity of the peak at m/z = 20 increased with increasing amounts of hydrogen fluoride generated. Furthermore, the helium flow rate during analysis using a quadrupole mass spectrometer can be set so that the gas generated from the polyimide can be analyzed in real time using the quadrupole mass spectrometer, for example, in the range of 50 mL/min to 150 mL/min, preferably in the range of 80 mL/min to 120 mL/min.

The inventors conducted research and discovered a strong correlation between the 20-wave peak intensity and the adhesion between the barrier film and the polyimide film after a heat test. Furthermore, the inventors discovered that by forming a laminate comprising a polyimide film and an inorganic film or glass, the temperature at which hydrogen fluoride begins to generate decreases, and the amount generated increases, compared to a single-layer structure comprising a polyimide film. This is presumably because the laminate prevents the volatilization of components including free radicals generated by heat, thereby promoting the auto-oxidation cycle of the polyimide.

The plasticizer used in this embodiment is preferably a material that is soluble in the solvent used during the imidization of the polyamine (1). In addition, in order to impart sufficient molecular mobility to the polyamine (1) during the imidization, the plasticizer is preferably non-volatile at low temperatures. Therefore, the boiling point of the plasticizer is preferably 50°C or higher, more preferably 100°C or higher, and further preferably 150°C or higher. In addition, in order to impart sufficient molecular mobility to the polyamine (1) during the imidization, the plasticizer preferably does not have a decomposition temperature below the boiling point.

From the viewpoint of avoiding decomposition of the plasticizer itself, the amount of the plasticizer is preferably 20 parts by weight or less relative to 100 parts by weight of the polyamine (1). Furthermore, from the viewpoint of imparting sufficient molecular mobility to the polyamine (1) and avoiding decomposition of the plasticizer itself, the amount of the plasticizer is preferably 0.001 parts by weight or more and 20 parts by weight or less relative to 100 parts by weight of the polyamine (1), more preferably 0.01 parts by weight or more and 15 parts by weight or less, further preferably 0.05 parts by weight or more and 10 parts by weight or less, further more preferably 0.05 parts by weight or more and 5 parts by weight or less.

Plasticizers not only enhance the molecular mobility of polyamine (1) during dehydration and ring closure to form polyimide, but also impart functions such as adjusting the glass transition temperature and flame retardancy. As the plasticizer, for example, one or more types of plasticizers can be appropriately selected from known plasticizers.

In order to further suppress the generation of hydrogen fluoride when used in high-temperature processes, the plasticizer is preferably one or more selected from the group consisting of phosphorus-containing compounds, polyalkylene glycols, and aliphatic dibasic acid esters.

Examples of phosphorus-containing compounds include compounds represented by the following general formulae (7-1) to (7-10). In the following general formulae (7-1) to (7-10), R ⁵ , R ⁶ , and R ⁷ independently represent a hydrogen atom, a monovalent organic group, or a polyvalent organic group; R ⁸ represents a polyvalent organic group; and n represents the degree of polymerization.

[Chemistry 6]

Preferred examples of phosphorus-containing compounds include phosphoric acid compounds, phosphorous acid compounds, phosphonic acid compounds, phosphinic acid compounds, phosphine compounds, phosphine oxide compounds, phosphane compounds, and phosphazene compounds. Phosphorus-containing compounds may be esters or condensates of the aforementioned compounds, may contain ring structures, or may form salts with amines. Furthermore, some of these phosphorus-containing compounds exhibit tautomeric isomerism, similar to phosphorous acid compounds and phosphonic acid compounds, and may exist in any state.

Specific examples of the phosphoric acid compound include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tris(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, tris(xylene) phosphate, tris(isopropylphenyl) phosphate, trinaphthyl phosphate, cresyl diphenyl phosphate, xylene diphenyl phosphate, diphenyl(2-ethylhexyl) phosphate, di(isopropylphenyl)phenyl phosphate, monoisodecyl phosphate, 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, melamine phosphate, dimelamine phosphate, bisphenol A bis(diphenyl phosphate), and tris(β-chloropropyl) phosphate.

Specific examples of the phosphorous acid compound include triphenyl phosphite, tris(nonylphenyl) phosphite, tricresyl phosphite, triethyl phosphite, triisobutyl phosphite, tris(2-ethylhexyl) phosphite, tridecyl phosphite, trilauryl phosphite, tri(tridecyl) phosphite, diphenyl phosphite, diethyl phosphite, dibutyl phosphite, dimethyl phosphite, diphenyl mono(2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl mono(tridecyl) phosphite, trilauryl trisulfide phosphite, diethyl phosphite, di ... di(2-ethylhexyl) phosphite, di(2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl mono(tridecyl) phosphite, di(2-ethylhexyl) phosphite, di(2-ethylhexyl) phosphite, diphenyl mono 2-ethylhexyl) ester, didodecyl phosphite, di[(Z)-9-octadecenyl] phosphite, diphenyl phosphite, tetraphenyldipropylene glycol diphosphite, bis(decyl)pentaerythritol diphosphite, bis(tridecyl)pentaerythritol diphosphite, tristearyl phosphite, distearylpentaerythritol diphosphite, tris(2,4-di-t-butylphenyl) phosphite, triisodecyl phosphite, 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxopyrazo-3,9-diphosphaspiro[5.5]undecane, etc.

Examples of the condensed product include condensed phosphate esters. Specific examples of condensed phosphate esters include trialkyl polyphosphate, resorcinol polyphenyl phosphate, resorcinol poly(di-2,6-xylyl) phosphate, and hydroquinone poly(2,6-xylyl) phosphate. Commercially available condensed phosphate esters include "CR-733S" manufactured by Daihachi Chemical Industries, Ltd., "CR-741" manufactured by Daihachi Chemical Industries, Ltd., and "FP-600" manufactured by Adeka Corporation.

Specific examples of phosphazene compounds include phenoxycyclophosphazene ("FP-110" manufactured by Fushimi Pharmaceutical Co., Ltd.) and cyclic cyanophenoxyphosphazene ("FP-300" manufactured by Fushimi Pharmaceutical Co., Ltd.).

Examples of the polyalkylene glycol include polypropylene glycol represented by the following general formula (8-1) and polyethylene glycol represented by the following general formula (8-2). In the following general formulas (8-1) and (8-2), n represents the degree of polymerization.

[Chemistry 7]

In order to improve the compatibility with polyamine (1), the number average degree of polymerization of the polyalkylene glycol is preferably 10 to 10,000, more preferably 10 to 6,000, and even more preferably 10 to 4,000.

Specific examples of aliphatic dibasic acid esters include dibutyl adipate, diisobutyl adipate, bis(2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, bis[2-(2-butoxyethoxy)ethyl] adipate, bis(2-ethylhexyl) azelaic acid, dibutyl sebacate, bis(2-ethylhexyl) sebacate, and diethyl succinate.

Furthermore, the plasticizer may be a low-molecular-weight organic compound or a thermoplastic resin as long as it can exert a plasticizing effect. Examples of such low-molecular-weight organic compounds include organic compounds having a molecular weight of approximately 1,000 or less, such as phenolic compounds; phthalimide compounds such as phthalimide, N-phenylphthalimide, N-glycidylphthalimide, N-hydroxyphthalimide, and cyclohexylsulfphthalimide; and phthalimide compounds such as N,N-phenylenediamine and 2,2-(ethylenedioxy)bis(ethylphthalimide). Examples of the thermoplastic resin include polyimide and polyamide having an asymmetric structure.

In order to further suppress the generation of hydrogen fluoride during use in high-temperature processes, the plasticizer is preferably a phosphite compound, more preferably a phosphite ester, and even more preferably triphenyl phosphite.

In order to obtain a polyimide with further reduced coloration, better transparency and heat resistance, and the ability to further suppress the generation of hydrogen fluoride during high-temperature processing, the polyimide composition of this embodiment preferably satisfies the following condition 1, more preferably satisfies the following condition 2, further preferably satisfies the following condition 3, and further preferably satisfies the following condition 4. Condition 1: The content of TFMB residues relative to all diamine residues constituting the polyimide (1) is 50 mol% or more and 100 mol% or less, and the polyimide (1) has one or more selected from the group consisting of PMDA residues, BPDA residues, BPAF residues, and ODPA residues. Condition 2: The above condition 1 is satisfied, and the polyamine (1) has only TFMB residues as diamine residues, or has only TFMB residues and 4-BAAB residues as diamine residues. Condition 3: The above condition 2 is satisfied, and the total content of PMDA residues, BPDA residues, BPAF residues, and ODPA residues relative to all dianhydride residues constituting the polyamine (1) is 100 mol%. Condition 4: The above condition 3 is satisfied, and the plasticizer is a phosphite-based compound.

The polyamine composition of the present embodiment may further contain an organic solvent in addition to the polyamine (1) and the plasticizer. Examples of the organic solvent contained in the polyamine composition include the organic solvents exemplified as the organic solvents that can be used in the synthesis reaction of the polyamine (1). Preferably, the organic solvent is one or more selected from the group consisting of amide solvents, ketone solvents, ester solvents, and ether solvents, and more preferably, an amide solvent (more specifically, DMF, DMAC, NMP, etc.). When polyamine (1) is obtained by the above method, the solution obtained by adding a plasticizer to the reaction solution (the solution after the reaction) can be used as the polyamine composition of this embodiment. Alternatively, the solid polyamine (1) and the plasticizer obtained by removing the solvent from the reaction solution can be dissolved in an organic solvent to prepare the polyamine composition of this embodiment. Furthermore, the content of polyamine (1) in the polyamine composition of this embodiment is not particularly limited, and for example, it is 1% by weight or more and 80% by weight or less relative to the total amount of the polyamine composition.

The polyimide of the present embodiment is an imide of the above-mentioned polyamic acid (1). The polyimide of the present embodiment can be obtained by a known method, and its production method is not particularly limited. Hereinafter, an example of a method for obtaining the polyimide of the present embodiment by imidizing the polyamic acid (1) will be described. The imidization is carried out by dehydrating and ring-closing the polyamic acid (1). The dehydration and ring-closing can be carried out by an azeotropic method using an azeotropic solvent, a thermal method, or a chemical method. In addition, the imidization from the polyamic acid (1) to the polyimide can take any ratio of more than 1% and less than 100%. That is, a partially imidized polyamine (1) can also be synthesized. In particular, when imidization is performed by heating, there is a possibility that the ring-closure reaction from polyamine (1) to polyimide and the hydrolysis of polyamine (1) proceed simultaneously, and the molecular weight of the polyimide produced is lower than the molecular weight of polyamine (1). Therefore, from the viewpoint of improving mechanical properties, it is preferable to preliminarily imidize a portion of the polyamine (1) in the polyamine composition before forming the polyimide film described below. In this specification, a partially imidized polyamine is sometimes also described as "polyamine".

The dehydration and ring closure of polyamine (1) can be carried out by simply heating the polyamine (1). The method for heating the polyamine (1) is not particularly limited. For example, the polyamine composition of the present embodiment (preferably a polyamine composition comprising polyamine (1), a plasticizer, and an organic solvent) can be coated on a support such as a glass substrate, a metal plate, or a PET film (polyethylene terephthalate film), and then the polyamine (1) can be heat-treated at a temperature within a range of 40°C to 500°C. According to this method, a laminate of the present embodiment having a support and a polyimide film (specifically, a polyimide film comprising an imide compound of polyamic acid (1)) disposed on the support is obtained. Alternatively, the polyamic acid composition can be directly placed in a container subjected to a demolding treatment such as coating with a fluororesin, and the polyamic acid composition can be heated and dried under reduced pressure to perform dehydration and ring closure of the polyamic acid (1). By dehydration and ring closure of the polyamic acid (1) performed by these methods, polyimide can be obtained. Furthermore, the heating time for each of the above treatments varies depending on the amount of polyamic acid composition being treated and the heating temperature, but is generally preferably set within a range of 1 minute to 300 minutes after the treatment temperature reaches its maximum temperature. Furthermore, to shorten the heating time or improve properties, an imidizing agent and/or a dehydrating catalyst may be added to the polyamic acid composition, and the polyamic acid composition to which the imidizing agent and/or dehydrating catalyst have been added may be heated to carry out imidization using the above method.

The imidizing agent is not particularly limited, and a tertiary amine can be used. A heterocyclic tertiary amine is preferred. Preferred examples of heterocyclic tertiary amines include pyridine, picoline, quinoline, isoquinoline, and 1,2-dimethylimidazole. Preferred examples of the dehydrating catalyst include acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride.

The amount of the imide agent added is preferably 0.5 times the molar equivalent to 5.0 times the molar equivalent, more preferably 0.7 times the molar equivalent to 2.5 times the molar equivalent, and further preferably 0.8 times the molar equivalent to 2.0 times the molar equivalent. Furthermore, the amount of the dehydrating catalyst added is preferably 0.5 times the molar equivalent to 10.0 times the molar equivalent, more preferably 0.7 times the molar equivalent to 5.0 times the molar equivalent, and further preferably 0.8 times the molar equivalent to 3.0 times the molar equivalent, relative to the amide group of the polyamide (1). Furthermore, in this specification, "amide groups of polyamide (1)" refer to amide groups generated by the polymerization reaction of diamine and tetracarboxylic dianhydride. When adding an imide agent and/or a dehydrating catalyst to the polyamide composition, they may be added directly without being dissolved in an organic solvent, or they may be added after being dissolved in an organic solvent. In the method of adding them directly without being dissolved in an organic solvent, there is a case where the imide agent and/or the dehydrating catalyst rapidly react before being diffused, thereby generating a gel. Therefore, it is preferred to add a solution obtained by dissolving the imide agent and/or the dehydrating catalyst in an organic solvent to the polyamide composition.

The polyimide film of the present embodiment (specifically, a polyimide film comprising an imide compound of polyamic acid (1)) is colorless, transparent, and has a low yellowness. It has a glass transition temperature (heat resistance) that can withstand the TFT manufacturing process and is therefore suitable for use as a transparent substrate material for a flexible display. The content of polyimide (specifically, an imide compound of polyamic acid (1)) in the polyimide film of the present embodiment is, for example, 70% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more, and can also be 100% by weight, relative to the total amount of the polyimide film. As components other than polyimide in the polyimide film, for example, the following additives (more specifically, nanosilica particles, etc.) can be cited.

The electronic device of this embodiment has the polyimide film of this embodiment and the electronic components arranged on the polyimide film. When manufacturing the electronic device of this embodiment for use in a flexible display, first, an inorganic substrate such as glass is used as a support, and a polyimide film is formed thereon. Then, by arranging (forming) electronic components such as TFTs on the polyimide film, an electronic device is formed on the support. The step of forming TFTs is usually carried out in a wide temperature range of above 150°C and below 650°C, but in order to actually achieve the desired performance, an oxide semiconductor layer or an a-Si (amorphous silicon) layer is formed at above 300°C, and depending on the situation, the a-Si layer is sometimes further crystallized using a laser or the like.

If the thermal decomposition temperature of the polyimide film is low, outgassing may occur during the formation of electronic components. This sublimation product may adhere to the oven, causing contamination or peeling of inorganic films (such as the barrier film described below) or electronic components formed on the polyimide film. Therefore, the 1% weight reduction temperature of the polyimide is preferably above 500°C. The upper limit of the 1% weight reduction temperature of the polyimide is preferably as high as possible, for example, 520°C. The 1% weight reduction temperature can be adjusted by varying the content of rigid residues (specifically, TFMB residues, PMDA residues, BPDA residues, etc.). To explain in more detail, before forming a TFT, an inorganic film such as a silicon oxide film (SiOx film) or a silicon nitride film (SiNx film) is formed on the polyimide film as a barrier film. If the polyimide has low heat resistance, imidization is not fully completed, or there is a large amount of residual solvent, the polyimide may peel off from the inorganic film during the high-temperature process after the inorganic film is deposited due to volatile components such as decomposition gases from the polyimide. Therefore, ideally, in addition to a 1% weight loss temperature of 500°C or higher, the weight loss rate of the polyimide should not exceed 1% when isothermally maintained at a temperature between 400°C and 450°C.

Furthermore, if the glass transition temperature (Tg) of polyimide is significantly lower than the process temperature, positional shifting may occur during the formation of electronic components. Therefore, the Tg of polyimide is preferably above 300°C, more preferably above 350°C, and even more preferably above 400°C. The upper limit of the Tg of polyimide is preferably as high as possible, for example, 450°C. Furthermore, the thermal expansion coefficient of a glass substrate is generally lower than that of a resin, resulting in internal stress between the glass substrate and the polyimide film. If the internal stress of the glass substrate used as a support or the laminate of electronic components and polyimide film is high, the laminate including the polyimide film will expand during the high-temperature TFT formation step and then contract when cooling to room temperature. This can cause problems such as warping or damage to the glass substrate and the polyimide film peeling from the glass substrate. Therefore, the internal stress generated by the laminate of polyimide film and glass substrate is preferably 30 MPa or less, more preferably 25 MPa or less, and even more preferably 20 MPa or less.

The polyimide of this embodiment is suitable for use as a material for display substrates such as TFT substrates and touch panel substrates. When using polyimide for these applications, in most cases, a method is employed in which an electronic device (specifically, an electronic device formed on a polyimide film) is formed on a support, as described above, and then the polyimide film is peeled off from the support. Furthermore, alkali-free glass is preferably used as the support material. The following describes in detail an example method for producing a laminate of a polyimide film and a support.

First, the polyamine composition of the present embodiment (preferably a polyamine composition comprising polyamine (1), a plasticizer, and an organic solvent) is coated on a support to form a coating-containing laminate. The coating-containing laminate comprises the coating containing polyamine (1) and the plasticizer, and the support. Next, the coating-containing laminate is heated at a temperature of, for example, 40° C. to 200° C. The heating time is, for example, 3 minutes to 120 minutes. Furthermore, for example, a multi-stage heating step may be provided, such as heating the coating film-containing laminate at 50°C for 30 minutes and then heating it at 100°C for 30 minutes. Next, in order to promote the imidization of the polyamide (1) in the coating film, the coating film-containing laminate is heated under conditions such as a maximum temperature of 200°C to 500°C. The heating time at this time (heating time at the maximum temperature) is, for example, 1 minute to 300 minutes. At this time, it is preferred to gradually increase the temperature from a low temperature to the maximum temperature. The heating rate is preferably 2°C/minute to 10°C/minute, and more preferably 4°C/minute to 10°C/minute. The maximum temperature is preferably in the range of 250°C to 450°C. If the maximum temperature is 250°C or higher, imidization proceeds fully, while if the maximum temperature is 450°C or lower, thermal degradation or coloration of the polyimide can be suppressed. Furthermore, the temperature can be maintained at any temperature for any time before reaching the maximum temperature. The imidization reaction can be carried out in air, under reduced pressure, or in an inert gas such as nitrogen. To achieve higher transparency, it is preferably carried out under reduced pressure or in an inert gas such as nitrogen. As a heating device, a hot air oven, an infrared oven, a vacuum oven, a non-oxidizing oven, a hot plate, or other known devices can be used. After these steps, the polyamide (1) in the coating film is imidized, and a laminate of a support and a polyimide membrane (a membrane comprising the imide of the polyamide (1)) can be obtained (i.e., the laminate of the present embodiment). In order to shorten the heating time or improve the properties, an imidizing agent or a dehydrating catalyst can be added to the polyamide composition, and the solution can be heated using the above method to carry out imidization.

The polyimide film can be peeled off from the obtained support and polyimide film laminate using a known method. For example, peeling can be performed manually, or using a mechanical device such as a drive roller or a robot. Furthermore, a method can be used in which a peeling layer is provided between the support and the polyimide film; or a method can be used in which a silicon oxide film is formed on a substrate having a plurality of grooves, the polyimide film is formed using the silicon oxide film as a base layer, and the polyimide film is peeled off by allowing an etching solution of silicon oxide to penetrate between the substrate and the silicon oxide film. Furthermore, a method can be used in which the polyimide film is separated by irradiating it with laser light.

If ridges exist at the interface between a polyimide film and a support (e.g., a glass substrate), there is a concern that the polyimide film may peel off during electronic device formation, or that the yield of the polyimide film may be reduced when the polyimide film is peeled off after electronic device formation. Furthermore, "ridges" refer to a condition where byproducts (specifically, hydrogen fluoride, etc.) generated during imidization or residual solvents cause poor adhesion between the polyimide film and other material layers (specifically, the glass substrate, barrier film, etc.). Specific examples of "lifting" include: a polyimide film lifting off a glass substrate; a polyimide film partially damaged, causing interlayer delamination between the polyimide film and other material layers; and a barrier film lifting off the polyimide film. The polyamide composition of this embodiment can suppress the generation of hydrogen fluoride when the resulting polyimide is used in a high-temperature process, thereby suppressing the occurrence of lifting.

The transparency of polyimide films can be evaluated using total light transmittance (TT) according to JIS K7361-1:1997 and haze according to JIS K7136-2000. When using polyimide films for applications requiring high transparency, the total light transmittance is preferably 75% or higher, more preferably 80% or higher. Furthermore, when using polyimide films for applications requiring high transparency, the haze is preferably 1.5% or lower, more preferably 1.2% or lower, and further preferably less than 1.0%, and may be 0%. In applications requiring high transparency, polyimide films are required to have high transmittance across the entire wavelength range. However, polyimide films tend to absorb short-wavelength light, often resulting in yellowish discoloration. To ensure the use of polyimide films in applications requiring high transparency, it is desirable to minimize discoloration. Specifically, to ensure the use of polyimide films in applications requiring high transparency, the yellowness index (YI) of the polyimide film is preferably 20 or less, more preferably 18 or less, even more preferably 15 or less, even more preferably 12 or less, and even more preferably 8 or less, with a value of 0 being acceptable. YI can be measured in accordance with JIS K7373-2006. YI can be adjusted, for example, by changing the content of TFMB residues in polyimide (1). Thus, the polyimide film with reduced coloration and enhanced transparency is suitable for use as a transparent substrate for glass replacement or a substrate with a sensor or camera module mounted on the back.

Furthermore, flexible displays use two light extraction methods: top emission, which extracts light from the TFT side, and bottom emission, which extracts light from the back side of the TFT. Top emission, because light is not blocked by the TFT, allows for a higher aperture ratio and high-definition image quality. Bottom emission, on the other hand, facilitates easy alignment of the TFT and pixel electrode, making it easier to manufacture. Transparent TFTs also increase the aperture ratio in bottom emission, leading to a trend toward using the easier-to-manufacture bottom emission method for large displays. The polyimide film of this embodiment has a low YI and excellent heat resistance, making it suitable for use with either of these light extraction methods.

Furthermore, in batch device manufacturing processes where a polyimide composition is coated on a support such as a glass substrate, heated for imidization, and then the polyimide film is peeled off to form electronic components, it is desirable to ensure excellent adhesion between the support and the polyimide film. Adhesion here refers to the strength of the bond. In the manufacturing process where electronic components are formed on the polyimide film on the support and then the polyimide film with the formed electronic components is peeled off from the support, excellent adhesion between the polyimide film and the support allows for more accurate formation or mounting of the electronic components. From the perspective of improving productivity, in the manufacturing process of placing electronic components on a support with a polyimide film interposed therebetween, the higher the peel strength between the support and the polyimide film, the better. Specifically, the peel strength is preferably 0.05 N/cm or greater, more preferably 0.1 N/cm or greater.

In the manufacturing process described above, when peeling the polyimide film from the support and the polyimide film laminate, the polyimide film is often peeled off by laser irradiation. In this case, the polyimide film must absorb the laser light, so the cutoff wavelength of the polyimide film must be longer than the wavelength of the laser light used for peeling. Laser stripping often uses a XeCl excimer laser with a wavelength of 308 nm, so the cutoff wavelength of the polyimide film is preferably above 312 nm, and more preferably above 330 nm. On the other hand, if the cutoff wavelength is longer, the polyimide film tends to discolor yellow, so the cutoff wavelength of the polyimide film is preferably below 390 nm. To balance transparency (low yellowing) and laser stripping processability, the cutoff wavelength of the polyimide film is preferably between 320 nm and 390 nm, more preferably between 330 nm and 380 nm. The cutoff wavelength in this specification refers to the wavelength at which the transmittance, as measured by a UV-visible spectrophotometer, falls below 0.1%.

The polyamine composition and polyimide of this embodiment can be used directly in a coating or forming process for manufacturing products or components, but can also be used as a material for further coating or other processing of a film-shaped formed object. In order to be used in a coating or forming process, the polyamine composition or polyimide can be dissolved or dispersed in an organic solvent as needed, and then, a photocurable component, a thermosetting component, a non-polymerizable binder resin and other components can be prepared as needed to prepare a composition containing polyamine (1) or polyimide.

To impart processing characteristics or various functionalities to the polyamide compositions and polyimides of this embodiment, various organic or inorganic low-molecular-weight compounds or high-molecular-weight compounds may be formulated as additives. Examples of additives include dyes, surfactants, leveling agents, plasticizers, silicones, microparticles, and sensitizers. Microparticles include organic microparticles such as polystyrene and polytetrafluoroethylene, or inorganic microparticles such as colloidal silica, carbon, and layered silicates, and may have porous or hollow structures. The function and morphology of the microparticles are not particularly limited; for example, they may be pigments, fillers, or fibrous particles.

In order to maintain the transparency of the polyimide film and improve the heat resistance, nanosilica particles can also be used as the above-mentioned additive, and polyamide (1) and nanosilica particles can be compounded. From the perspective of maintaining the transparency of the polyimide film, the average primary particle size of the nanosilica particles is preferably 200 nm or less, more preferably 100 nm or less, further preferably 50 nm or less, and can also be 30 nm or less. On the other hand, from the perspective of ensuring dispersibility into polyamide (1), the average primary particle size of the nanosilica particles is preferably 5 nm or more, more preferably 10 nm or more. As a method for compounding polyamine (1) with nanosilica particles, a known method can be used. For example, a method using an organosilicon sol prepared by dispersing nanosilica particles in an organic solvent can be cited. As a method for compounding polyamine (1) with nanosilica particles using an organosilicon sol, a method of synthesizing polyamine (1) and then mixing the synthesized polyamine (1) with the organosilicon sol can also be used. However, in order to disperse the nanosilica particles more highly in the polyamine (1), it is preferred to synthesize the polyamine (1) in the organosilicon sol.

Furthermore, in order to enhance the interaction with polyamide (1), the surface of the nano-silica particles can also be treated with a surface treatment agent. As the surface treatment agent, a well-known surface treatment agent such as a silane coupling agent can be used. As the silane coupling agent, alkoxysilane compounds having an amino group or a glycidyl group as a functional group are well known and can be appropriately selected. In order to further enhance the interaction with polyamide (1), an alkoxysilane containing an amino group is preferably used as the silane coupling agent. Examples of amino group-containing alkoxysilanes include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 2-aminophenyltrimethoxysilane, and 3-aminophenyltrimethoxysilane. However, from the perspective of raw material stability, 3-aminopropyltriethoxysilane is preferably used. One example of a surface treatment method for nanosilica particles involves adding a silane coupling agent to a dispersion (organic silica sol) and stirring the resulting mixture at an ambient temperature of 20°C to 80°C. The stirring time is, for example, 1 to 10 hours. A catalyst to promote the reaction may also be added.

Regarding the nanosilica-polyamide composite formed by compounding polyamide (1) with nanosilica particles, the nanosilica particles are preferably contained in a range of 1 to 30 parts by weight relative to 100 parts by weight of polyamide (1), and more preferably in a range of 1 to 20 parts by weight. If the content of the nanosilica particles is 1 part by weight or more, the heat resistance of the polyimide containing the nanosilica particles can be improved and the internal stress can be sufficiently reduced. If the content of the nanosilica particles is 30 parts by weight or less, the adverse effects on the mechanical properties and transparency of the polyimide containing the nanosilica particles can be suppressed.

In the polyamine composition of the present embodiment, imidazoles may also be added as the additive for imparting functionality. In this specification, imidazoles refer to compounds having a 1,3-oxadiazole ring (1,3-oxadiazole ring structure). There is no particular limitation on the imidazoles added to the polyamine composition of the present embodiment, and examples thereof include: 1H-imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-benzimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-benzimidazole, and the like. Among them, 1,2-dimethylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-benzimidazole are preferred, and 1,2-dimethylimidazole and 1-benzyl-2-methylimidazole are more preferred.

The content of imidazoles per 1 mol of amide groups in the polyamide (1) is preferably 0.005 mol or more and 0.1 mol or less, more preferably 0.01 mol or more and 0.08 mol or less, and even more preferably 0.015 mol or more and 0.050 mol or less. By containing 0.005 mol or more of imidazoles, the film strength and transparency of the polyimide can be improved, and by setting the imidazole content to 0.1 mol or less, the storage stability of the polyamide (1) can be maintained, and the Tg or heat resistance can be improved. Regarding the improvement in transparency, it is known that polymerization solvents such as NMP form complexes with the carboxyl groups of polyamide (1) using hydrogen bonds. When the imidization rate is slow, NMP and the like may remain in the polyimide film and cause coloration due to oxidation or decomposition. If imidazoles are added, the imidazoles coordinate to the carboxyl groups of polyamide (1) and promote imidization, so that NMP and the like are less likely to remain in the polyimide film. At the same time, the decomposition of polyamide (1) during the thermal imidization process is also suppressed, which is believed to improve transparency. According to the polyamine composition of this embodiment, a plasticizer is used to provide sufficient molecular mobility during the imidization of the polyamine (1), so that imidazoles may not be used in this embodiment.

There is no particular limitation on the method for mixing polyamine (1) and imidazoles. From the viewpoint of the ease of controlling the molecular weight of polyamine (1), it is preferable to add imidazoles to the polyamine (1) after polymerization. In this case, the imidazoles can be added directly to the polyamine (1), or the imidazoles can be dissolved in a solvent in advance and the solution added to the polyamine (1). The method of addition is not particularly limited. The polyamine composition of this embodiment can also be prepared by adding imidazoles and a plasticizer to a solution containing the polyamine (1) after polymerization (the solution after the reaction).

Furthermore, in order to exhibit appropriate adhesion to the support, the polyamine composition of this embodiment may contain a silane coupling agent. The type of the silane coupling agent may be any known silane coupling agent, but from the viewpoint of reactivity with polyamine (1), compounds containing an amino group are particularly preferred.

The mixing ratio of the silane coupling agent to 100 parts by weight of the polyimide (1) is preferably 0.01 parts by weight or more and 0.50 parts by weight or less, more preferably 0.01 parts by weight or more and 0.10 parts by weight or less, and even more preferably 0.01 parts by weight or more and 0.05 parts by weight or less. By setting the mixing ratio of the silane coupling agent to 0.01 parts by weight or more, the peeling-inhibiting effect relative to the support can be fully exerted. By setting the mixing ratio of the silane coupling agent to 0.50 parts by weight or less, the decrease in the molecular weight of the polyimide (1) can be suppressed, thereby suppressing the embrittlement of the polyimide film.

Various inorganic thin films, such as metal oxide thin films or transparent electrodes, can also be formed on the surface of the polyimide film of this embodiment. The methods for forming these inorganic thin films are not particularly limited, and examples thereof include PVD (Physical Vapor Deposition) methods such as sputtering, vacuum evaporation, and ion plating, or CVD (Chemical Vapor Deposition) methods.

The polyimide film of this embodiment not only exhibits heat resistance, low thermal expansion, and transparency, but also generates minimal internal stress when laminated with a glass substrate. Furthermore, it maintains close adhesion to inorganic materials during high-temperature processes. Therefore, it is ideally suited for applications and products where these properties can be utilized. For example, the polyimide film of this embodiment is particularly well-suited for use in liquid crystal displays, organic EL, electronic paper, and other image display devices, printed materials, color filters, flexible displays, optical films, 3D displays, touch panels, transparent conductive film substrates, and solar cells. Furthermore, it is particularly well-suited as a replacement material for applications currently using glass. In such applications, the thickness of the polyimide film is, for example, 1 μm to 200 μm, preferably 5 μm to 100 μm. The thickness of the polyimide film can be measured using a laser holo gauge.

Furthermore, the polyamide composition of this embodiment is suitable for use in a batch device manufacturing process in which the polyamide composition is coated on a support, heated to undergo imidization, and after forming electronic components, the polyimide film is peeled off. Therefore, this embodiment also includes a method for manufacturing an electronic device, comprising the steps of coating the polyamide composition on a support, heating to undergo imidization, and forming electronic components, etc., on the polyimide film formed on the support. Furthermore, this method for manufacturing an electronic device may further include the step of peeling the polyimide film on which the electronic components, etc. are formed from the support. [Examples]

Hereinafter, embodiments of the present invention will be described, but the scope of the present invention is not limited to the following embodiments.

<Methods for Measuring Physical Properties and Evaluating Adhesion> First, we will explain methods for measuring the physical properties of polyimide (polyimide film) and evaluating its adhesion.

[Yellowness (YI)] The transmittance of the polyimide films in each of the laminates obtained in the following Examples and Comparative Examples was measured using an ultraviolet-visible-near-infrared spectrophotometer (V-650, manufactured by JASCO Corporation) for light with a wavelength of 200 nm to 800 nm. The yellowness (YI) of the polyimide films was calculated using the formula described in JIS K7373-2006. A YI of 20 or less was evaluated as "capable of reducing coloration of the polyimide film." On the other hand, a YI exceeding 20 was evaluated as "unable to reduce coloration of the polyimide film."

[Haze] The haze of the polyimide films peeled from the laminates obtained in the following Examples and Comparative Examples was measured using an integrating sphere haze meter ("HM-150N" manufactured by Murakami Color Research Laboratory Co., Ltd.) according to the method described in JIS K7136-2000. A haze value of less than 1.0% was evaluated as "excellent transparency." On the other hand, a haze value of 1.0% or greater was evaluated as "poor transparency."

[Internal Stress] The polyimide compositions prepared in the following Examples and Comparative Examples were applied using a spin coater onto a Corning Inc. glass substrate (material: alkali-free glass, thickness: 0.7 mm, size: 100 mm × 100 mm) whose warp had been previously measured. The substrates were then heated at 120°C in air for 30 minutes and then at 430°C in a nitrogen atmosphere for 30 minutes. The resulting laminates had a 10 μm-thick polyimide film on the glass substrate. To eliminate the effects of water absorption by the polyimide film, the laminate was dried at 120°C for 10 minutes. The warp of the laminate was then measured at 25°C in a nitrogen atmosphere using a thin film stress tester (FLX-2320-S, manufactured by KLA-Tencor). The internal stress generated between the glass substrate and the polyimide film was then calculated using Stoney's equation based on the warp of the glass substrate before and after the polyimide film was formed.

[Glass Transition Temperature (Tg)] Polyimide films 3 mm wide and 10 mm long were sampled from each of the laminates obtained in the following Examples and Comparative Examples as samples for Tg measurement. Using a thermal analyzer ("TMA/SS7100" manufactured by Hitachi High-Tech Science Corporation), a load of 98.0 mN was applied to the sample. The temperature was raised from 20°C to 450°C at a rate of 10°C/min. A TMA curve was plotted against the strain (elongation). The temperature at the inflection point of the obtained TMA curve (the temperature corresponding to the peak in the differential curve of the TMA curve) was defined as the glass transition temperature (Tg). A Tg of 350°C or higher was evaluated as "excellent heat resistance." On the other hand, if the Tg is less than 350°C, it is evaluated as having poor heat resistance.

[1% Weight Loss Temperature (TD1)] The polyimide films obtained in the following Examples and Comparative Examples (specifically, polyimide films sampled from each laminate to a weight of 10 mg) were used as test samples. A differential thermal analyzer (TG/DTA7200, manufactured by Hitachi High-Tech Science Corporation) was used to measure the temperature from 25°C to 650°C at a rate of 20°C/min under a nitrogen atmosphere. The 1% weight loss temperature (TD1) was defined as the temperature at which the sample weight at a measurement temperature of 150°C decreased by 1% by weight relative to the reference weight.

[Existence of Bumps Between the Glass Substrate and the Polyimide Film] The polyamide compositions prepared in the following Examples and Comparative Examples were coated onto glass substrates manufactured by Corning (material: alkali-free glass, thickness: 0.7 mm, size: 100 mm × 100 mm) using a spin coater. The coatings were then heated at 120°C in air for 30 minutes and then at 430°C in a nitrogen atmosphere for 30 minutes. Laminates with a 10 μm thick polyimide film on the glass substrate were obtained. The laminates were visually inspected for the presence of bumps between the glass substrate and the polyimide film.

[Presence of Bumps Between SiOx Film and Polyimide Film] The polyamide compositions prepared in the following Examples and Comparative Examples were applied to glass substrates (material: alkali-free glass, thickness: 0.7 mm, size: 100 mm × 100 mm) manufactured by Corning Incorporated using a spin coater. The substrates were heated at 120°C in air for 30 minutes and then at 430°C in a nitrogen atmosphere for 30 minutes to form a 10 μm thick polyimide film on the glass substrates. Subsequently, a SiOx film (thickness: 1 μm) was deposited on the resulting polyimide film using plasma CVD. The resulting laminate was heated in a nitrogen atmosphere under the heating conditions shown in Table 4. The heated laminate was then visually inspected for the presence of bulges between the SiOx film and the polyimide film. Furthermore, the presence of bulges between the SiOx film and the polyimide film was inspected for Examples 1 to 18, Comparative Examples 1 to 5, and Comparative Example 10 described below.

[Analysis of Gases Emitted from Polyimide Membranes] Gases generated from polyimide membranes during heating were analyzed using a combined thermogravimetric analyzer (NETZSCH STA449 F5) and a quadrupole mass spectrometer (JEOL JMS-Q1500GC). The analysis procedure is described below.

First, using perfluorotributylamine as a standard substance, the voltage of the quadrupole mass spectrometer was adjusted to achieve a detection intensity of 800,000 for the peak at m/z = 69. Subsequently, using the thermogravimetric apparatus, the polyimide membranes obtained in the following Examples and Comparative Examples (specifically, polyimide membranes sampled from each laminate at a mass of 140 mg) were heated from an ambient temperature of 60°C at a rate of 10°C/min under a helium flow rate of 100 mL/min. When the ambient temperature reached 470°C, the gases generated from the polyimide membranes were analyzed using the quadrupole mass spectrometer. Furthermore, by heating the polyimide membrane under a helium flow using the aforementioned analysis device, with helium serving as the carrier gas, the gases generated from the polyimide membrane can be analyzed in real time using the aforementioned quadrupole mass spectrometer. The mass spectrum obtained from the gases generated from the polyimide membrane when the atmosphere temperature reached 470°C was analyzed using the aforementioned quadrupole mass spectrometer, and the detection intensity of the peak at m/z = 20 (the 20 peak intensity) was read. If the 20 peak intensity was below 60,000, it was evaluated as "hydrogen fluoride generation was suppressed during the high-temperature process." On the other hand, if the 20 peak intensity exceeded 60,000, it was evaluated as "hydrogen fluoride generation was not suppressed during the high-temperature process."

<Polyimide Membrane Preparation> The following describes methods for preparing polyimide membranes (laminated structures) in Examples and Comparative Examples. Compounds and reagents are described using the following abbreviations. The polyamide solutions used in preparing the polyimide membranes were prepared under a nitrogen atmosphere. NMP: N-methyl-2-pyrrolidone PMDA: Pyromellitic dianhydride BPAF: 9,9-Bis(3,4-dicarboxyphenyl)fluorene dianhydride BPDA: 3,3',4,4'-Biphenyltetracarboxylic dianhydride ODPA: 4,4'-Oxydiphthalic anhydride 4-BAAB: 4-aminophenyl 4-aminobenzoate PDA: p-phenylenediamine TFMB: 2,2'-Bis(trifluoromethyl)benzidine ODA: 4,4'-Diaminodiphenyl ether TPP: Triphenyl phosphate TMP: Trimethyl phosphate DEPi: Diethyl phosphite TPPi: Triphenyl phosphite PEP-36: 3,9-Bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxo-3,9-diphosphaspiro[5.5]undecane 3010: Triisodecyl phosphite PX-200: Resorcinol poly(di-2,6-xylyl) phosphate CR-741: Condensed phosphate ("CR-741" manufactured by Daba Chemical Industries) DBA: Dibutyl adipate BXA-N: Di[2-(2-butoxyethoxy)ethyl adipate] PEG600: Polyethylene glycol (average molecular weight 560-640)

[Preparation of Polyamine Solution] (Preparation of Polyamine Solution PA-2) To a 300 mL glass separable flask equipped with a stirrer with a stainless steel stir bar and a nitrogen inlet, 40.0 g of NMP was added as the polymerization organic solvent. While stirring, 5.453 g of TFMB was added and dissolved. Subsequently, 2.439 g of PMDA, 0.788 g of BPAF, and 1.265 g of BPDA were added to the flask. The contents were stirred at 25°C for 24 hours to obtain Polyamine Solution PA-2.

(Preparation of Polyamine Solutions PA-1 and PA-3 to PA-10) Polyamine solutions PA-1 and PA-3 to PA-10 were prepared using the same method as polyamine solution PA-2, except that the acid dianhydrides used and their feed ratios, the diamines used and their feed ratios, and the ratio of the total mass of the diamines used to the total mass of the acid dianhydrides used were set as shown in Table 1. Furthermore, the total mass of the acid dianhydrides in each of polyamine solutions PA-1 and PA-3 to PA-10 was the same as that in polyamine solution PA-2.

In Table 1, "-" means that the component was not used. Furthermore, in Table 1, the values in the "Acid Dianhydride" column are the content ratios of each acid dianhydride relative to the total amount of acid dianhydrides used (unit: mole %). In Table 1, the values in the "Diamine" column are the content ratios of each diamine relative to the total amount of diamines used (unit: mole %). In Table 1, "ratio" means the ratio of the total mass of diamines used to the total mass of acid dianhydrides used (total mass of diamines/total mass of acid dianhydrides). Furthermore, for any of the polyamic acid solutions PA-1 to PA-10, the molar fractions of the various residual groups of the polyamic acid in the prepared polyamic acid solution were consistent with the molar fractions of the various monomers (diamine and tetracarboxylic dianhydride) used in the synthesis of the polyamic acid.

[Table 1] Polyamine solution Acid dianhydride [mol %] Diamine [mol %] Compare PMDA BPDA BPAF ODPA TFMB 4-BAAB ODA PDA PA-1 60 25 15 - 100 - - - 0.99 PA-2 65 25 10 - 100 - - - 0.99 PA-3 65 25 10 - 100 - - - 1.02 PA-4 75 15 10 - 100 - - - 0.99 PA-5 80 - 10 10 100 - - - 0.99 PA-6 - 90 10 - 40 60 - - 1.00 PA-7 - 90 10 - 60 40 - - 1.00 PA-8 - 90 10 - 40 - 60 - 1.00 PA-9 - 90 10 - 60 - 40 - 1.00 PA-10 - 100 - - - - - 100 1.00

[Example 1] TMP was added as a plasticizer to polyimide solution PA-1 under a nitrogen atmosphere, and the resulting mixture was stirred for 5 minutes to obtain a polyimide composition. The amount of TMP added was 1 part by weight per 100 parts by weight of polyimide in polyimide solution PA-1. The resulting polyimide composition was coated onto a glass substrate (Corning Incorporated, material: alkali-free glass, thickness: 0.7 mm, size: 100 mm × 100 mm) using a spin coater. The coating was then heated at 120°C in air for 30 minutes, and then at 430°C in a nitrogen atmosphere for 30 minutes. A laminate having a 10 μm thick polyimide film on the glass substrate was obtained.

[Examples 2-20 and Comparative Examples 1-10] A laminate having a 10 μm thick polyimide film on a glass substrate was obtained by the same method as in Example 1, except that the type of polyimide solution used, and the type and amount of plasticizer used, were set as shown in Table 2. In Table 2, "-" indicates that no plasticizer was used. Therefore, in Comparative Examples 1-10, polyimide solutions PA-1 to PA-10, respectively, were used as the polyimide composition. In Table 2, the amount of plasticizer added is expressed in parts by weight relative to 100 parts by weight of the polyimide in the polyimide solution used.

[Table 2] Types of polyamine solutions Plasticizer Kind Addition amount [parts by weight] Example 1 PA-1 TMP 1 Example 2 PA-2 TMP 1 Example 3 PA-2 TMP 5 Example 4 PA-2 TPP 1 Example 5 PA-2 TPP 5 Example 6 PA-2 DEPi 1 Example 7 PA-2 DEPi 5 Example 8 PA-2 TPPi 1 Example 9 PA-2 PX-200 1 Example 10 PA-2 CR-741 1 Example 11 PA-2 PEG600 1 Example 12 PA-2 PEG600 5 Example 13 PA-2 DBA 1 Example 14 PA-2 BXA-N 1 Example 15 PA-3 PX-200 1 Example 16 PA-4 PEP-36 0.05 Example 17 PA-4 3010 0.05 Example 18 PA-5 PX-200 1 Example 19 PA-6 TPP 1 Example 20 PA-7 TPP 1 Comparative example 1 PA-1 - Comparative example 2 PA-2 - Comparative example 3 PA-3 - Comparative example 4 PA-4 - Comparative example 5 PA-5 - Comparative example 6 PA-6 - Comparative example 7 PA-7 - Comparative example 8 PA-8 - Comparative example 9 PA-9 - Comparative example 10 PA-10 -

<Physical Properties and Evaluation Results> Tables 3 and 4 show the physical properties and evaluation results for Examples 1-20 and Comparative Examples 1-10. In Table 3, "-" indicates that the measurement was not performed. Furthermore, in Table 3, "presence of bulging between the glass substrate and the polyimide film" refers to the presence of bulging between the glass substrate and the polyimide film. Furthermore, in Table 4, "presence of bulging between the SiOx film and the polyimide film" refers to the presence of bulging between the SiOx film and the polyimide film.

FIG1 shows the results of analyzing gases generated from polyimide membranes using a quadrupole mass spectrometer according to the method described in [Analysis of Gases Generated from Polyimide Membranes] for Example 18 and Comparative Example 5. In FIG1 , the vertical axis represents detection intensity, and the horizontal axis represents temperature (ambient temperature). In FIG1 , the solid line represents the change in detection intensity of the peak at m/z = 20 in Comparative Example 5, while the dashed line represents the change in detection intensity of the peak at m/z = 20 in Example 18. As shown in FIG1 , it can be seen that Example 18 has a smaller detection intensity of the peak at m/z=20 near an ambient temperature of 470°C than Comparative Example 5, thereby suppressing the generation of hydrogen fluoride when used in a high-temperature process.

[Table 3] YI Haze[%] Internal stress [MPa] Tg [℃] TD1 [℃] Is there any bulge between the glass substrate? 20 peak intensity Example 1 8 0.3 17 >350 >500 without 23,635 Example 2 12 0.7 11 >350 >500 without 24,507 Example 3 12 0.8 18 >350 >500 without 24,369 Example 4 14 0.4 9 >350 >500 without 20,307 Example 5 11 0.4 11 >350 >500 without 21,918 Example 6 11 0.3 10 >350 >500 without 26,389 Example 7 10 0.3 9 >350 >500 without 51,397 Example 8 12 0.7 19 >350 >500 without 18,470 Example 9 10 0.3 13 >350 >500 without 19,806 Example 10 10 0.3 12 >350 >500 without 24,477 Example 11 16 0.3 13 >350 >500 without 59,475 Example 12 17 0.5 12 >350 >500 without 47,211 Example 13 9 0.3 11 >350 >500 without 54,141 Example 14 9 0.4 11 >350 >500 without 41,041 Example 15 9 0.3 10 >350 >500 without 22,117 Example 16 8 0.3 13 >350 >500 without 27,097 Example 17 8 0.5 15 >350 >500 without 26,638 Example 18 9 0.3 13 >350 >500 without 21,279 Example 19 9 0.6 5 >350 >500 without 13,597 Example 20 8 0.7 10 >350 >500 without 16,719 Comparative example 1 8 0.2 18 >350 >500 without 75,046 Comparative example 2 12 0.3 11 >350 >500 without 76,916 Comparative example 3 11 0.3 3 >350 >500 without 70,527 Comparative example 4 10 0.4 2 >350 >500 without 74,922 Comparative example 5 11 0.2 2 >350 >500 without 77,896 Comparative example 6 11 0.4 2 >350 >500 without 60,524 Comparative example 7 14 0.5 1 >350 >500 without 64,170 Comparative example 8 20 2.3 31 292 >500 without 19,249 Comparative example 9 16 2.6 27 300 >500 without 32,914 Comparative example 10 28 0.5 3 >350 >500 have -

[Table 4] Is there any bulge between the SiOx film? Heating conditions: 400℃, 60 minutes Heating conditions: 430℃, 60 minutes Heating conditions: 470℃, 10 minutes Example 1 without without without Example 2 without without without Example 3 without without without Example 4 without have without Example 5 without without without Example 6 without have without Example 7 without without have Example 8 without without without Example 9 without without without Example 10 without without without Example 11 without have have Example 12 without without have Example 13 without without have Example 14 without without without Example 15 without without without Example 16 without without have Example 17 without without have Example 18 without without without Comparative example 1 have have have Comparative example 2 have have have Comparative example 3 have have have Comparative example 4 have have have Comparative example 5 have have have Comparative example 10 without without without

As described above, in Examples 1 to 20 using a polyamine composition containing a polyamine having a structural unit (1) and a plasticizer, all of the following conditions (1) to (6) are satisfied. (1) YI is 20 or less. (2) Haze is less than 1.0%. (3) Internal stress is 30 MPa or less. (4) Tg is 350°C or more. (5) TD1 is 500°C or more. (6) 20 peak strength is 60,000 or less.

In Comparative Examples 1-7, the 20 peak intensity exceeded 60,000. Therefore, the polyimide films obtained in Comparative Examples 1-7 were unable to suppress the generation of hydrogen fluoride during high-temperature processing. In Comparative Examples 8 and 9, the Tg did not reach 350°C. Therefore, the polyimide films obtained in Comparative Examples 8 and 9 had poor heat resistance. In Comparative Example 10, the YI exceeded 20. Therefore, the polyimide film obtained in Comparative Example 10 failed to reduce coloration.

The above results show that the polyimide obtained from the polyamic acid composition of the present invention not only has low coloration, excellent transparency and heat resistance, but also can inhibit the generation of hydrogen fluoride during high-temperature processes.

FIG1 is a graph showing the results of analyzing the polyimide membranes of Example 18 and Comparative Example 5 using a quadrupole mass spectrometer.

Claims (14)

A polyamine composition comprising a polyamine comprising a structural unit represented by the following general formula (1) and a plasticizer, wherein the polyamine has 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride as X in the following general formula (1); [Chemical 1] (In the above general formula (1), ^R1 and ^R2 each independently represent a hydrogen atom, a monovalent aliphatic group or a monovalent aromatic group, and X represents a tetravalent organic group). The polyamine composition of claim 1, wherein in the general formula (1), R ¹ and R ² both represent hydrogen atoms. The polyamine composition of claim 1 or 2, wherein the polyamine further comprises, as X in the general formula (1), one or more groups selected from the group consisting of a tetravalent organic group represented by the following chemical formula (2), a tetravalent organic group represented by the following chemical formula (3), and a tetravalent organic group represented by the following chemical formula (5); [Chemical 2] . The polyamine composition of claim 1 or 2, wherein the content of the structural unit represented by the general formula (1) is 50 mol% or more and 100 mol% or less relative to all the structural units of the polyamine. The polyamine composition of claim 1 or 2, wherein the amount of the plasticizer is 20 parts by weight or less relative to 100 parts by weight of the polyamine. The polyamic acid composition of claim 1 or 2, wherein the plasticizer is one or more selected from the group consisting of phosphorus-containing compounds, polyalkylene glycols, and aliphatic dibasic acid esters. The polyamine composition of claim 1 or 2 further comprises an organic solvent. A polyimide, which is an imide of the polyamic acid contained in the polyamic acid composition of any one of claims 1 to 7. For example, the polyimide of claim 8 has a 1% weight loss temperature of 500°C or higher. The 1% weight loss temperature is the temperature at which the weight of the sample decreases by 1% by weight relative to a test temperature of 150°C. A polyimide film comprising the polyimide of claim 8 or 9. The polyimide film of claim 10 has a yellowness index of 20 or less. A laminate comprising a support and the polyimide film according to claim 10 or 11. A method for producing a laminate comprising a support and a polyimide film, wherein the polyimide composition of claim 7 is coated on the support to form a coating film comprising the polyimide and the plasticizer, and the coating film is heated to imidize the polyimide. An electronic device comprising the polyimide film of claim 10 or 11, and an electronic element disposed on the polyimide film.