KR20230056652A - Polyamic acid composition, polyimide, polyimide film, laminate, method for producing laminate and electronic device - Google Patents

Abstract

The polyamic acid composition contains a polyamic acid containing a structural unit represented by the following general formula (1) and a plasticizer. A polyimide is an imide of a polyamic acid containing a structural unit represented by the following general formula (1). The polyimide film contains an imide of a polyamic acid containing a structural unit represented by the following general formula (1). The layered product has a support and a polyimide film containing an imide of polyamic acid containing a structural unit represented by the following general formula (1). An electronic device has a polyimide film containing an imide of a polyamic acid containing 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 producing laminate and electronic device

The present invention relates to a polyamic acid composition, a polyimide, a polyimide film, a laminate, a method for producing the laminate, and an electronic device. The present invention also 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 display devices, organic EL, electronic paper etc.), 3D displays, solar cells, touch panels, transparent conductive film substrates, and alternative materials for members currently using glass.

DESCRIPTION OF RELATED ART With the rapid progress of displays, such as a liquid crystal display, organic EL, and electronic paper, and electronic devices, such as a solar cell and a touch panel, thinning, weight reduction, and flexibility of devices are progressing. In these devices, polyimide is used as a substrate material instead of a glass substrate.

In these devices, various electronic elements such as thin film transistors and transparent electrodes are formed on a substrate, and high-temperature processes are required to form these electronic elements. Polyimide has sufficient heat resistance to be able to adapt to high-temperature processes, and its coefficient of thermal expansion (CTE) is close to that of glass substrates and electronic elements, so internal stress is unlikely to occur, making it suitable for substrate materials such as flexible displays.

In general, aromatic polyimide is colored yellowish brown due to intramolecular conjugation or formation of charge transfer (CT) complexes. Instead, conventional aromatic polyimide has been used. However, when light emitted from a display element is emitted through a substrate, such as a transparent display, a bottom emission type organic EL, or a liquid crystal display, or a sensor or camera module is used to make a smartphone or the like a full-surface display (notchless). In the case of disposing on the back side of a substrate, high optical properties (more specifically, transparency, etc.) have been sought for the substrate as well.

From this background, there is a demand for a material with reduced coloration and excellent transparency while having heat resistance equivalent to that of conventional aromatic polyimides.

In order to reduce the coloring of polyimide, a technique for suppressing the formation of a CT complex using an aliphatic monomer (Patent Documents 1 and 2) and a technique for increasing transparency using a monomer having a fluorine atom or a sulfur atom (Patent Documents 1 and 2) 3) is known.

Although the polyimides described in Patent Literatures 1 and 2 have high transparency and low CTE, they have a low thermal decomposition temperature because they have an aliphatic structure, and it is difficult to apply them to high-temperature processes when forming electronic elements.

Japanese Unexamined Patent Publication No. 2016-29177 Japanese Unexamined Patent Publication No. 2012-41530 Japanese Unexamined Patent Publication No. 2014-70139

Since the polyimide described in Patent Literature 3 contains fluorine atoms, it has been found by the present inventors' examination that there is a possibility of generating hydrogen fluoride in a high-temperature process. When hydrogen fluoride is generated, poor adhesion may occur between the polyimide film and the barrier film or the like, or corrosion of electronic elements provided on the polyimide film may occur.

The present invention has been made in view of the above circumstances, and provides a polyimide with reduced coloration, excellent transparency, high heat resistance, and capable of suppressing the generation of hydrogen fluoride in a high-temperature process, and a polyamic acid composition as a precursor thereof. intended to provide Another object is to provide a product or member manufactured using the polyimide and polyamic acid compositions and requiring heat resistance and transparency. In particular, an object of the present invention is to provide a product or member in which the polyimide film is formed on the surface of an inorganic material such as glass, metal, metal oxide, and single crystal silicon.

As a result of intensive studies, the present inventors have found that a polyimide obtained from a composition containing a specific polyamic acid and a plasticizer has reduced coloring, excellent transparency, high heat resistance, and suppresses the generation of hydrogen fluoride during a high-temperature process. It was found that it could be done, and the present invention was completed.

The polyamic acid composition according to the present invention contains a polyamic acid containing a structural unit represented by the following general formula (1) and a plasticizer.

In the above general formula (1), R ¹ and R ² each independently represent a hydrogen atom, a monovalent aliphatic group or a monovalent aromatic group, and X represents a tetravalent organic group.

In the polyamic acid composition according to one embodiment of the present invention, both R ¹ and R ² in the general formula (1) represent a hydrogen atom.

In the polyamic acid composition according to one embodiment of the present invention, X in the general formula (1) is a tetravalent organic group represented by the following formula (2) or a tetravalent organic group represented by the following formula (3) , a tetravalent organic group represented by the following formula (4), and a tetravalent organic group represented by the following formula (5).

In the polyamic acid composition according to one embodiment of the present invention, the content of the structural unit represented by the general formula (1) is 50 mol% or more and 100 mol% or less with respect to all structural units of the polyamic acid.

In the polyamic acid composition according to one embodiment of the present invention, the amount of the plasticizer is 20 parts by weight or less with respect to 100 parts by weight of the polyamic acid.

In the polyamic acid composition according to 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.

The polyamic acid composition according to one embodiment of the present invention further contains an organic solvent.

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

It is preferable that the 1% weight loss temperature of the polyimide concerning this invention is 500 degreeC or more.

The polyimide film according to the present invention includes the polyimide according to the present invention.

It is preferable that the yellowness of the polyimide film concerning this invention is 20 or less.

A laminate according to the present invention has a support and a polyimide film according to the present invention.

In the method for producing a laminate according to the present invention, the polyamic acid composition according to one embodiment of the present invention is coated on a support to form a coating film containing polyamic acid and a plasticizer, and the coating film is heated. The polyamic acid is imidized.

An electronic device according to the present invention includes a polyimide film according to the present invention and an electronic element disposed on the polyimide film.

The polyimide produced using the polyamic acid composition according to the present invention has reduced coloration, excellent transparency and heat resistance, and can suppress generation of hydrogen fluoride during a high-temperature process. Therefore, the polyimide produced using the polyamic acid composition according to the present invention is suitable as a material for electronic devices that require low colorability, transparency, and heat resistance, and are manufactured through a high-temperature process.

1 is a graph showing the results obtained by analyzing polyimide films according to Example 18 and Comparative Example 5 with a quadrupole mass spectrometer.

Preferred embodiments of the present invention will be described in detail below, but the present invention is not limited thereto.

First, terms used in this specification will be described. A "structural unit" refers to a repeating unit constituting a polymer. "Polyamic acid" is a polymer containing a structural unit represented by the following general formula (6) (hereinafter sometimes referred to as "structural unit (6)"). In addition, in this specification, not only polyamic acid but also polyamic acid esters (polyamic acid alkyl esters, polyamic acid aryl esters, etc.) are described as "polyamic acid".

In general formula (6), R ³ and R ⁴ each independently represent a hydrogen atom, a monovalent aliphatic group, or a monovalent aromatic group, and A ¹ is, for example, a tetracarboxylic dianhydride residue (tetracarb represents a tetravalent organic group derived from boxylic acid dianhydride), and A ² represents, for example, a diamine residue (divalent organic group derived from diamine).

The content of the structural unit (6) relative to all the structural units constituting the polyamic acid is, for example, 50 mol% or more and 100 mol% or less, preferably 60 mol% or more and 100 mol% or less, more preferably It is 70 mol% or more and 100 mol% or less, More preferably, it is 80 mol% or more and 100 mol% or less, Even more preferably, it is 90 mol% or more and 100 mol% or less, 100 mol% may be sufficient.

"1% weight reduction temperature" is a measurement temperature when the weight of polyimide at a measurement temperature of 150°C is reduced by 1% by weight relative to the reference weight (100% by weight). The measuring method of 1% weight loss temperature is the same method as that of the Example mentioned later, or a method similar to it.

"m/z" is a measurement value that can be read from the horizontal axis of the mass spectrum, which is the measurement result of mass spectrometry, and "the dimensionless quantity obtained by dividing the mass of an ion by the unified atomic mass unit (dalton) is also It is a dimensionless quantity obtained by dividing by the absolute value.

A "plasticizer" refers to a material that exists as a liquid at the time of imidation of at least a part of polyamic acid.

Hereinafter, "system" is appended to the name of a compound to collectively refer to a compound and its derivatives in some cases. When a polymer name is indicated by attaching "system" to the end of the compound name, it means that the repeating unit of the polymer is derived from a compound or a derivative thereof. In addition, tetracarboxylic dianhydride may be described as "acid dianhydride".

The polyamic acid composition according to the present embodiment contains a polyamic acid containing a structural unit represented by the following general formula (1) (hereinafter sometimes referred to as "structural unit (1)") and a plasticizer do.

In General Formula (1), R ¹ and R ² each independently represent a hydrogen atom, a monovalent aliphatic group or a monovalent aromatic group, and X represents a tetravalent organic group. In order to imidate easily, as ^R1 and ^R2 , a hydrogen atom, a methyl group, or an ethyl group is each independently preferable, and it is more preferable that both ^R1 and ^R2 represent a hydrogen atom. Hereinafter, unless otherwise specified, a structural unit in which R ¹ and R ² in General Formula (1) both represent hydrogen atoms is referred to as structural unit (1).

Since the polyamic acid composition according to the present embodiment contains the polyamic acid containing the structural unit (1) and a plasticizer, when polyimide is produced using the polyamic acid composition according to the present embodiment, coloring It is possible to obtain a polyimide that is reduced, has excellent transparency and heat resistance, and can suppress the generation of hydrogen fluoride during a high-temperature process.

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

TFMB has a rigid structure and is suitable as a raw material (monomer) of polyimide having a high glass transition temperature (excellent in heat resistance). In addition, since TFMB has a trifluoromethyl group, it is suitable as a raw material (monomer) of polyimide with reduced coloring and high transparency.

When synthesizing a polyamic acid containing structural unit (1) (hereinafter sometimes referred to as "polyamic acid (1)"), a diamine other than TFMB is used as a monomer within a range that does not impair its performance. You can use it. Examples of diamines other than TFMB include 4-aminophenyl-4-aminobenzoate (hereinafter sometimes referred to as "4-BAAB"), 1,4-diaminocyclohexane, and p-phenylenediamine. , m-phenylenediamine, 9,9-bis(4-aminophenyl)fluorene, 4,4'-oxydianiline, 3,4'-oxydianiline, 2,2'-bis(trifluoromethyl )-4,4'-diaminodiphenyl ether, 4,4'-diaminobenzanilide, N,N'-bis(4-aminophenyl)terephthalamide, 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(cyclohexanamine), 1,3-bis(3-aminopropyl)tetramethyldisiloxane and their derivatives are mentioned, and you may use these individually or 2 or more types.

From the viewpoint of improving heat resistance, 4-BAAB is preferred as diamines other than TFMB. Therefore, from the viewpoint of improving heat resistance, the polyamic acid (1) preferably has a 4-BAAB residue. Since 4-BAAB has a rigid structure, it is suitable as a raw material (monomer) of polyimide having excellent heat resistance. In addition, 4-BAAB having a rigid structure is also suitable as a raw material (monomer) of polyimide having high mechanical strength while suppressing generation of internal stress.

In order to obtain a polyimide with reduced coloration, better heat resistance, and higher transparency, the polyamic acid (1) has only TFMB residues as diamine residues, or TFMB residues and 4-BAAB residues as diamine residues It is desirable to have only

In order to obtain a polyimide with reduced coloration and superior heat resistance, the content of the TFMB residue relative to all the diamine residues constituting the polyamic acid (1) is preferably 30 mol% or more, and more preferably 40 mol% or more. It is preferably 50 mol% or more, more preferably 60 mol% or more, even more preferably 70 mol% or more, 80 mol% or more, 90 mol% or more, or even 100 mol%.

In order to obtain a polyimide with reduced coloring and more excellent heat resistance, the content of the structural unit (1) is preferably 30 mol% or more and 100 mol% or less with respect to all the structural units of the polyamic acid (1), and 40 It is more preferably 100 mol% or less, more preferably 50 mol% or more and 100 mol% or less, still more preferably 60 mol% or more and 100 mol% or less, 70 mol% or more and 100 mol% or less, 80 mol% or more It may be % or more and 100 mol% or less, or 90 mol% or more and 100 mol% or less, and even if it is 100 mol%, it does not matter.

When the polyamic acid (1) has a 4-BAAB residue, in order to obtain a polyimide having better heat resistance, the content of the 4-BAAB residue relative to all the diamine residues constituting the polyamic acid (1) is 10 mol%. It is preferably above, more preferably 20 mol% or more, and still more preferably 30 mol% or more. In addition, when polyamic acid (1) has a 4-BAAB residue, in order to obtain a polyimide with reduced coloring, the content of 4-BAAB residue relative to all diamine residues constituting polyamic acid (1) is It is preferably 70 mol% or less, more preferably 60 mol% or less, still more preferably 50 mol% or less, and still more preferably 40 mol% or less.

When the polyamic acid (1) has a TFMB residue and a 4-BAAB residue, in order to obtain a polyimide with reduced coloration, better heat resistance, and higher transparency, constituting the polyamic acid (1) The total content of TFMB residues and 4-BAAB residues relative to all diamine residues is preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more, and still more 80 mol% or more. More preferably, 90 mol% or more may be sufficient, and even if it is 100 mol%, it does not matter.

As the tetracarboxylic acid dianhydride (acid dianhydride giving X in general formula (1)) for synthesizing the polyamic acid (1), for example, pyromellitic acid dianhydride (hereinafter described as "PMDA") may be used), 3,3',4,4'-biphenyltetracarboxylic dianhydride (hereinafter sometimes referred to as "BPDA"), p-phenylene bis(trimellitate anhydride), 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic 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(trifluoro) Romethyl) xanthene 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, and these may be used alone or in combination of two or more.

In order to obtain a polyimide capable of further suppressing the generation of hydrogen fluoride during a high-temperature process, an acid dianhydride that does not contain a fluorine atom is preferable as the acid dianhydride giving X in the general formula (1). That is, in order to obtain a polyimide capable of further suppressing the generation of hydrogen fluoride during a high-temperature process, it is preferable that the acid dianhydride residue constituting the polyamic acid (1) does not contain a fluorine atom.

As the acid dianhydride giving X in General Formula (1), at least one selected from the group consisting of PMDA, BPDA, BPAF and ODPA is preferable. That is, the polyamic acid (1) preferably has at least one selected from the group consisting of a PMDA residue, a BPDA residue, a BPAF residue, and an ODPA residue as X in the general formula (1).

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

In order to obtain a polyimide having excellent heat resistance, reducing internal stress, and having high mechanical strength, the polyamic acid (1) preferably contains at least one selected from the group consisting of PMDA residues and BPDA residues. . In order to obtain a polyimide with higher transparency, it is preferable that the polyamic acid (1) has at least one selected from the group consisting of a BPAF residue and an ODPA residue.

When polyamic acid (1) has at least one selected from the group consisting of PMDA residues, BPDA residues, BPAF residues and ODPA residues, PMDA residues for all acid dianhydride residues constituting polyamic acid (1) , the total content of BPDA residue, BPAF residue and ODPA residue is preferably 60 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, and still more preferably 90 mol% or more, It may be 100 mol%. When the total content of PMDA residues, BPDA residues, BPAF residues and ODPA residues relative to all acid dianhydride residues constituting polyamic acid (1) is 60 mol% or more, internal stress can be reduced while transparency and heat resistance are better. At the same time, polyimide with high mechanical strength can be obtained.

When the polyamic acid (1) has a PMDA residue, in order to obtain a polyimide having excellent heat resistance, reduced internal stress and high mechanical strength, the content of the PMDA residue is It is preferably 30 mol% or more and 100 mol% or less, more preferably 40 mol% or more and 90 mol% or less, and still more preferably 50 mol% or more and 80 mol% or less with respect to the total acid dianhydride residues constituting it.

When the polyamic acid (1) has a BPDA residue, in order to obtain a polyimide having excellent heat resistance, reduced internal stress and high mechanical strength, the content of the BPDA residue is It is preferably 10 mol% or more and 100 mol% or less, and more preferably 10 mol% or more and 90 mol% or less with respect to the total acid dianhydride residues constituting it.

When the polyamic acid (1) has a BPAF residue, in order to obtain a polyimide having higher transparency, the content of the BPAF residue is 1 mol% or more relative to the total acid dianhydride residues constituting the polyamic acid (1). It is preferably 3 mol% or more, more preferably 5 mol% or more, still more preferably 10 mol% or more. Further, when the polyamic acid (1) has a BPAF residue, in order to reduce the internal stress, the content of the BPAF residue is preferably 50 mol% or less relative to the total acid dianhydride residues constituting the polyamic acid (1). And, it is more preferably 40 mol% or less, and even more preferably 30 mol% or less.

When the polyamic acid (1) has an ODPA residue, in order to obtain a polyimide having higher transparency, the content of the ODPA residue is 1 mol% or more relative to the total acid dianhydride residues constituting the polyamic acid (1). It is preferable, and it is more preferable that it is 3 mol% or more, and it is more preferable that it is 5 mol% or more. Further, when the polyamic acid (1) has an ODPA residue, in order to reduce the internal stress, the content of the ODPA residue is preferably 50 mol% or less relative to the total acid dianhydride residues constituting the polyamic acid (1). And, it is more preferably 40 mol% or less, and even more preferably 30 mol% or less.

Polyamic acid (1) can be synthesized by a known general method, and can be obtained, for example, by reacting diamine with tetracarboxylic dianhydride in an organic solvent. An example of a specific method for synthesizing polyamic acid (1) will be described. First, in an inert gas atmosphere such as argon or nitrogen, a diamine solution is prepared by dissolving or dispersing diamine in an organic solvent in the form of a slurry. Then, tetracarboxylic dianhydride is dissolved in an organic solvent or dispersed in a slurry state, or added to the diamine solution in a solid state.

In the case of synthesizing polyamic acid (1) using diamine and tetracarboxylic dianhydride, the amount of substance of diamine (substance amount of each diamine when using plural types of diamine) and the amount of substance of tetracarboxylic dianhydride ( When using multiple types of tetracarboxylic dianhydride, desired polyamic acid (1) (diamine and the polymer of tetracarboxylic dianhydride) can be obtained by adjusting the amount of substance of each tetracarboxylic dianhydride. The molar fraction of each residue in the polyamic acid (1) coincides with the molar fraction of each monomer (diamine and tetracarboxylic dianhydride) used in the synthesis of the polyamic acid (1), for example. Further, by blending two types of polyamic acid, polyamic acid (1) containing plural types of tetracarboxylic dianhydride residues and plural types of diamine residues can also be obtained. The temperature conditions for the reaction between diamine and tetracarboxylic dianhydride, ie, the synthesis reaction of polyamic acid (1), are not particularly limited, but are, for example, in the range of 20°C or more and 150°C or less. The reaction time of the synthesis reaction of polyamic acid (1) is in the range of, for example, 10 minutes or more and 30 hours or less.

The organic solvent used for synthesis of polyamic acid (1) is preferably a solvent capable of dissolving the tetracarboxylic dianhydride and diamine used, and more preferably a solvent capable of dissolving the produced polyamic acid (1). Examples of organic solvents used for synthesis of polyamic acid (1) include urea solvents such as tetramethylurea and N,N-dimethylethylurea; sulfoxide-based solvents such as dimethyl sulfoxide; sulfone solvents such as diphenyl sulfone and tetramethyl sulfone; N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), hexamethylphosphate triamide, etc. of amide-based solvent; ester solvents such as γ-butyrolactone; halogenated alkyl solvents such as chloroform and methylene chloride; aromatic hydrocarbon solvents such as benzene and toluene; phenolic solvents such as phenol and cresol; ketone solvents such as cyclopentanone; 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; can Although these solvents are usually used individually, you may use them combining 2 or more types suitably as needed. In order to increase the solubility and reactivity of polyamic acid (1), the organic solvent used in the synthesis reaction of polyamic acid (1) is selected from the group consisting of amide solvents, ketone solvents, ester solvents and ether solvents One or more solvents are preferred, and amide-based solvents (more specifically, DMF, DMAC, NMP, etc.) are more preferred. The synthesis reaction of polyamic acid (1) is preferably carried out under an inert gas atmosphere such as argon or nitrogen.

The weight average molecular weight of the polyamic acid (1) varies depending on the application, but is preferably in the range of 10,000 or more and 1,000,000 or less, more preferably in the range of 20,000 or more and 500,000 or less, and still more in the range of 30,000 or more and 200,000 or less. desirable. When the weight average molecular weight is 10,000 or more, it becomes easy to use the polyamic acid (1) or the polyimide obtained using the polyamic acid (1) as a coating film or a polyimide film (film). On the other hand, if the weight average molecular weight is 1,000,000 or less, sufficient solubility in solvents is exhibited, so that a coating film or polyimide film having a smooth surface and uniform thickness can be obtained using the polyamide acid composition described later. The weight average molecular weight used in this specification refers to the value in terms of polyethylene oxide measured using gel permeation chromatography (GPC).

In addition, as a method for controlling the molecular weight of polyamic acid (1), a method in which either acid dianhydride or diamine is excessive, or a reaction by reacting with a monofunctional acid anhydride or amine such as phthalic anhydride or aniline, There are ways to name it. In the case of polymerization with an excess of either acid dianhydride or diamine, a polyimide film having sufficient strength can be obtained when the charged molar ratio thereof is between 0.95 and 1.05. In addition, the molar ratio above is the ratio of the total amount of diamine used in the synthesis of polyamic acid (1) to the total amount of acid dianhydride used in the synthesis of polyamic acid (1) (total amount of diamine/acid dianhydride) total amount of substance). Moreover, coloring of the polyimide obtained using polyamic acid (1) can also be further reduced by terminal sealing with phthalic anhydride, maleic anhydride, aniline, etc.

Next, the effect of the plasticizer contained in the polyamic acid composition according to the present embodiment (hereinafter, simply referred to as "plasticizer") will be described. In general, when it is desired to obtain a transparent polyimide film, in principle, a polyimide having a large HOMO and LUMO band gap can be designed, so TFMB having a low electron donating property is effective for obtaining a transparent polyimide film. On the other hand, since TFMB with low electron donating property has low nucleophilicity, it is expected that the reaction rate and imidation rate will be slow. When the present inventors examined the imidation rate, the following findings were obtained. That is, when the imidation rates of general colored polyimides obtained from BPDA and p-phenylenediamine and transparent polyimides obtained from PMDA, BPDA, and TFMB were compared, the colored polyimide was 90% at an imidation reaction temperature of 300 ° C. As described above, nearly 100% of imidation was achieved at an imidation reaction temperature of 350°C, but in transparent polyimide, only about 75% was imidized at an imidation reaction temperature of 300°C and only about 80% was imidized even at an imidation reaction temperature of 350°C. A clear difference was observed in the imidization rate.

In general, the driving force at the time of dehydration ring closure from polyamic acid to polyimide by thermal imidation is largely due to molecular motion by heat and plasticizing effect by solvent. Treatment above the transition temperature is preferred. However, in a combination of rigid acid dianhydride such as PMDA and TFMB, the polyimide obtained has a glass transition temperature exceeding 400°C, and the glass transition temperature may be higher than the heat treatment temperature during film formation. Therefore, in the imidation reaction between rigid acid dianhydrides such as PMDA and TFMB, there is a possibility that imidation does not proceed completely. For this reason, for example, in a high-temperature process using a polyimide film (for example, TFT annealing), imidation of unreacted portions in the polyimide film proceeds, and the production of low molecular weight components from the polyimide film Outgas (for example, hydrogen fluoride, etc.) is generated, and peeling of the barrier film or corrosion of the TFT may occur. On the other hand, according to the polyamic acid composition according to the present embodiment, sufficient molecular motion is imparted at the time of imidation of polyamic acid (1) by using a plasticizer, and imidation not only proceeds completely, but also polyamic acid ( Depolymerization of 1) is also suppressed, and generation of outgas (particularly, hydrogen fluoride) can be suppressed. In addition, according to the polyamic acid composition according to the present embodiment, molecular motion is imparted to the polyamic acid (1) so that the solvent is easily removed, the amount of residual solvent in the film (polyimide film) is reduced, and the degree of coloration of the film is reduced. is reduced

As a result of investigation by the present inventors, it was found that imidation in the presence of a plasticizer reduces the amount of residual solvent in the film and greatly reduces the generated outgas itself. In particular, in the case of using TFMB as a monomer, it was found that the amount of hydrogen fluoride gas generated when the obtained polyimide was used in a high-temperature process was suppressed by imidation in the presence of a plasticizer. Since the polyamic acid composition according to the present embodiment contains a plasticizer, generation of hydrogen fluoride can be suppressed during a high-temperature process. For this reason, according to the polyamic acid composition according to the present embodiment, in the manufacturing process of the flexible display, for example, since corrosion of the barrier film formed on the polyimide film or the glass serving as the support substrate is suppressed, the flexible display Reliability (hard to cause trouble) can be improved. Furthermore, according to the polyamic acid composition according to the present embodiment, since sufficient molecular motion is imparted at the time of imidation of the polyamic acid (1) by using a plasticizer, imidation is promoted and a polyimide excellent in heat resistance is obtained. is obtained In addition, the plasticizer may remain in the polyimide film, or may be decomposed and removed from the polyimide film in the process of imidation. When the plasticizer remains in the polyimide film, in order to obtain a polyimide film having more excellent heat resistance, the content of the plasticizer relative to the total amount of the polyimide film is preferably 0.01% by weight or less, more preferably 0.001% by weight or less, and 0.0001% by weight It is more preferable that it is % or less.

In addition, since the polyamic acid composition according to the present embodiment contains a plasticizer, even if the content of TFMB residues is high (for example, even if it is 50 mol% or more with respect to all diamine residues), the obtained polyimide is subjected to a high-temperature process. Generation of hydrogen fluoride during use can be suppressed.

As an indicator of the amount of hydrogen fluoride gas generated when the imidate of polyamic acid (1) (the polyimide according to the present embodiment) is used in a high-temperature process, the detection intensity obtained from the mass spectrum can be cited. In detail, first, the polyimide is heated under a helium gas flow at an atmospheric temperature of 60 ° C. at a heating rate of 10 ° C./min, and when the atmospheric temperature reaches 470 ° C., the gas generated from the polyimide is measured with a quadrupole mass spectrometer. Analyze with And, from the obtained mass spectrum (specifically, a mass spectrum showing the result of analyzing the components of the gas generated from the polyimide when the atmospheric temperature reached 470 ° C.), m / z = 20 estimated to be due to hydrogen fluoride The peak detection intensity (hereinafter sometimes referred to as "20 peak intensity") is read. As the amount of hydrogen fluoride generated increases, the 20 peak intensity tends to increase. In addition, the helium gas flow rate at the time of analysis with the quadrupole mass spectrometer may be set so that the gas generated from the polyimide can be analyzed with the quadrupole mass spectrometer in real time, for example, 50 mL/min or more and 150 mL/min. It is the following range, Preferably it is the range of 80 mL/min or more and 120 mL/min or less.

As a result of investigation by the present inventors, it was found that the 20 peak intensity and the adhesion between the barrier film and the polyimide film after the heating test exhibited a very high correlation. Further, as a result of investigation by the present inventors, the temperature at which hydrogen fluoride starts to be generated is lowered and the amount of hydrogen fluoride generated is lower than in the case of a single-layer structure including a polyimide film by forming a laminate in which a polyimide film and an inorganic film or glass are laminated. I knew This is presumed to be because, by forming a laminate, components containing radicals generated by heat cannot be volatilized, and the auto-oxidation cycle of polyimide is promoted.

As the plasticizer used in the present embodiment, a material that dissolves in the solvent used in imidation of the polyamic acid (1) is preferable. In addition, it is preferable that the plasticizer does not volatilize at low temperatures in order to impart sufficient molecular mobility to the polyamic acid (1) during imidation. Therefore, the boiling point of the plasticizer is preferably 50°C or higher, more preferably 100°C or higher, and still more preferably 150°C or higher. Further, the plasticizer preferably does not have a decomposition temperature below the boiling point in order to impart sufficient molecular mobility to the polyamic acid (1) during imidation.

The amount of the plasticizer is preferably 20 parts by weight or less with respect to 100 parts by weight of the polyamic acid (1) from the viewpoint of avoiding decomposition of the plasticizer itself. Further, the amount of the plasticizer is preferably 0.001 part by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the polyamic acid (1) from the viewpoint of avoiding decomposition of the plasticizer itself while imparting sufficient molecular mobility to the polyamic acid (1). , It is more preferably 0.01 part by weight or more and 15 parts by weight or less, more preferably 0.05 part by weight or more and 10 parts by weight or less, and still more preferably 0.05 part by weight or more and 5 parts by weight or less.

The plasticizer not only improves the molecular motion at the time of dehydration ring closure of the polyamic acid (1) into the polyimide, but can also impart functions such as adjustment of the glass transition temperature and flame retardancy. As a plasticizer, it can use, selecting suitably 1 type(s) or 2 or more types from well-known plasticizers, for example.

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

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

Preferable examples of the phosphorus-containing compound include phosphoric acid compounds, phosphorous acid compounds, phosphonic acid compounds, phosphinic acid compounds, phosphine compounds, phosphine oxide compounds, phospholane compounds, phosphazene compounds and the like. The phosphorus-containing compound may be an ester of the compounds listed above or a condensate thereof, may contain a cyclic structure, or may form a salt with an amine or the like. In addition, among these phosphorus-containing compounds, there are also those having a tautomeric relationship, such as phosphorous acid-based compounds and phosphonic acid-based compounds, but they may exist in either state.

Specific examples of the phosphoric acid compound include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris( isopropylphenyl)phosphate, trinaphthylphosphate, cresyldiphenylphosphate, xylenyldiphenylphosphate, diphenyl(2-ethylhexyl)phosphate, di(isopropylphenyl)phenylphosphate, monoisodecylphosphate, 2-acrylo ethyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, melamine phosphate, dimelamine phosphate, bisphenol A bis(diphenyl phosphate), tris(β-chloropropyl) phosphate, etc. are mentioned.

Specific examples of the phosphorous acid compound include triphenyl phosphite, trisnonylphenyl phosphite, tricresyl phosphite, triethyl phosphite, triisobutyl phosphite, tris(2-ethylhexyl) phosphite, and tridecyl phosphite. , trilauryl phosphite, tris (tridecyl) phosphite, diphenyl phosphite, diethyl phosphite, dibutyl phosphite, dimethyl phosphite, diphenylmono (2-ethylhexyl) phosphite, diphenyl monodecyl Phosphite, diphenylmono(tridecyl)phosphite, trilauryl trithiophosphite, diethylhydrogen phosphite, bis(2-ethylhexyl)hydrogen phosphite, dilauryl hydrogen phosphite, dioleyl hydro Genphosphite, diphenylhydrogenphosphite, tetraphenyldipropylene glycol diphosphite, bis(decyl)pentaerythritol diphosphite, bis(tridecyl)pentaerythritol diphosphite, tristearyl phosphite, distearylpenta Erythritol diphosphite, tris (2,4-di-tert-butylphenyl) phosphite, triisodecyl phosphite, 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy)- 2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, etc. are mentioned.

As said condensate, condensed phosphoric acid ester is mentioned. Specific examples of the condensed phosphoric acid ester include trialkyl polyphosphate, resorcinol polyphenyl phosphate, resorcinol poly(di-2,6-xylyl) phosphate, hydroquinone poly(2,6-xylyl) phosphate, and the like. can As a commercial item of condensed phosphate ester, "CR-733S" by Daihachi Chemical Industry Co., Ltd., "CR-741" by Daihachi Chemical Industry Co., Ltd., "FP-600" by ADEKA company etc. are mentioned, for example.

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

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

In order to improve the compatibility with polyamic acid (1), the number average polymerization degree of polyalkylene glycol is preferably 10 or more and 10,000 or less, more preferably 10 or more and 6,000 or less, and still more preferably 10 or more and 4,000 or less.

Specific examples of the aliphatic dibasic acid ester include dibutyl adipate, diisobutyl adipate, bis(2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, bis[2-(2-butoxy) Ethoxy) ethyl] adipate, bis (2-ethylhexyl) azelate, dibutyl sebacate, bis (2-ethylhexyl) sebacate, diethyl succinate, etc. are mentioned.

In addition, a low molecular weight organic compound or a thermoplastic resin may be sufficient as a plasticizer, as long as it exhibits a plasticizing effect. Examples of the low molecular weight organic compound include organic compounds having a molecular weight of about 1,000 or less, and examples thereof include phenolic compounds; phthalimide-based compounds such as phthalimide, N-phenylphthalimide, N-glycidylphthalimide, N-hydroxyphthalimide, and cyclohexylthiophthalimide; and maleimide compounds such as N,N-p-phenylenebismaleimide and 2,2-(ethylenedioxy)bis(ethylmaleimide). As said thermoplastic resin, polyimide, polyamide, etc. which have an asymmetric structure are mentioned.

In order to further suppress the generation of hydrogen fluoride when used in a high-temperature process, as the plasticizer, a phosphorous acid compound is preferable, a phosphorous acid ester is more preferable, and a triphenylphosphite is still more preferable.

In order to obtain a polyimide with further reduced coloration, further excellent transparency and heat resistance, and capable of further suppressing the generation of hydrogen fluoride during a high-temperature process, the polyamide acid composition according to the present embodiment satisfies condition 1 below. It is preferable to satisfy, it is more preferable to satisfy condition 2 below, it is even more preferable to satisfy condition 3 below, and it is even more preferable to satisfy condition 4 below.

Condition 1: The content of TFMB residues relative to all diamine residues constituting polyamic acid (1) is 50 mol% or more and 100 mol% or less, and polyamic acid (1) is PMDA residue, BPDA residue, BPAF residue, and ODPA It has 1 or more types selected from the group which consists of residues.

Condition 2: The above condition 1 is satisfied, and the polyamic acid (1) has only TFMB residues as diamine residues, or only TFMB residues and 4-BAAB residues as diamine residues.

Condition 3: The above condition 2 is satisfied, and the total content ratio of PMDA residues, BPDA residues, BPAF residues, and ODPA residues to all acid dianhydride residues constituting polyamic acid (1) is 100 mol%.

Condition 4: The condition 3 above is satisfied, and the plasticizer is a phosphorous acid-based compound.

The polyamic acid composition according to the present embodiment may further contain an organic solvent in addition to the polyamic acid (1) and the plasticizer. Examples of the organic solvent contained in the polyamic acid composition include organic solvents exemplified as organic solvents usable for the synthesis reaction of the polyamic acid (1), amide solvents, ketone solvents, ester solvents, and ether solvents. One or more solvents selected from the group consisting of solvents are preferred, and amide-based solvents (more specifically, DMF, DMAC, NMP, etc.) are more preferred. When polyamic acid (1) is obtained by the method described above, the solution itself obtained by adding a plasticizer to the reaction solution (solution after reaction) may be used as the polyamic acid composition according to the present embodiment. Alternatively, the polyamic acid composition according to the present embodiment may be prepared by dissolving the solid polyamic acid (1) obtained by removing the solvent from the reaction solution and the plasticizer in an organic solvent. The content of the polyamic acid (1) in the polyamic acid composition according to the present embodiment is not particularly limited, but is, for example, 1% by weight or more and 80% by weight or less with respect to the total amount of the polyamic acid composition.

The polyimide according to the present embodiment is an imide of the polyamic acid (1) described above. The polyimide according to the present embodiment can be obtained by a known method, and the production method thereof is not particularly limited. Hereinafter, an example of a method for obtaining the polyimide according to the present embodiment by imidizing the polyamic acid (1) will be described. Imidation is performed by dehydration ring closure of polyamic acid (1). This dehydration ring closure can be performed by an azeotropic method using an azeotrope solvent, a thermal method, or a chemical method. In addition, imidation from polyamic acid (1) to polyimide can take any ratio of 1% or more and 100% or less. That is, you may synthesize|combine the polyamic acid (1) which partly imidated. In particular, in the case of imidation by heating, the ring closure reaction from polyamic acid (1) to polyimide and the hydrolysis of polyamic acid (1) proceed simultaneously, and the molecular weight when made into polyimide is polyamide. Since the molecular weight of the acid (1) may be lower than that, it is preferable from the viewpoint of improving mechanical properties to imidize a part of the polyamic acid (1) in the polyamic acid composition in advance before forming the polyimide film described later. . In this specification, a polyamic acid partially imidated is sometimes described as "polyamic acid".

The dehydration ring closure of the polyamic acid (1) may be performed by heating the polyamic acid (1). The method of heating the polyamic acid (1) is not particularly limited. For example, the polyamic acid composition according to the present embodiment described above is placed on a support such as a glass substrate, a metal plate, or a PET film (polyethylene terephthalate film). (Preferably, the polyamic acid composition containing polyamic acid (1), a plasticizer and an organic solvent) is applied, and then heat treatment of the polyamic acid (1) is performed within a temperature range of 40 ° C. or more and 500 ° C. or less. do. According to this method, a laminate according to the present embodiment having a support and a polyimide film (specifically, a polyimide film containing an imide of polyamic acid (1)) disposed on the support is obtained. lose Alternatively, the polyamic acid composition (1) can also be dehydrated and cyclized by directly putting the polyamic acid composition into a container subjected to release treatment such as coating with a fluorine-based resin, and heating and drying the polyamic acid composition under reduced pressure. Polyimide can be obtained by dehydration ring closure of polyamic acid (1) by these methods. The heating time for each of the above treatments varies depending on the treatment amount of the polyamic acid composition subjected to dehydration and ring closure and the heating temperature, but generally, it is preferable to set the treatment temperature within the range of 1 minute or more to 300 minutes or less after the treatment temperature reaches the maximum temperature. desirable. In addition, in order to shorten the heating time or develop characteristics, an imidation agent and/or a dehydration catalyst are added to the polyamic acid composition, and the polyamic acid composition to which the imidation agent and/or dehydration catalyst is added is heated by the above method. You can imidize it.

Although it does not specifically limit as said imidation agent, A tertiary amine can be used. As the tertiary amine, a heterocyclic tertiary amine is preferable. Preferable specific examples of the heterocyclic tertiary amine include pyridine, picoline, quinoline, isoquinoline, and 1,2-dimethylimidazole. Preferable examples of the dehydration catalyst include acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride.

The addition amount of the imidation agent is preferably 0.5 times molar equivalent or more and 5.0 times molar equivalent or less, more preferably 0.7 times molar equivalent or more and 2.5 times molar equivalent or less, relative to the amide group of polyamic acid (1), and 0.8 times molar equivalent Above 2.0 times molar equivalent or less is more preferable. The addition amount of the dehydration catalyst is preferably 0.5-fold molar equivalent or more and 10.0-fold molar equivalent or less, more preferably 0.7-fold molar equivalent or more and 5.0-fold molar equivalent or less, relative to the amide group of polyamic acid (1), and 0.8-fold molar equivalent It is more preferable to have an equivalent weight or more and 3.0 times molar equivalent or less. In addition, in this specification, "the amide group of polyamic acid (1)" refers to the amide group produced|generated by the polymerization reaction of diamine and tetracarboxylic dianhydride. When adding an imidation agent and/or a dehydration catalyst to the polyamic acid composition, it may be added directly without dissolving in an organic solvent, or may be added dissolved in an organic solvent. In the method of adding directly without dissolving in an organic solvent, the reaction proceeds rapidly before the imidation agent and/or the dehydration catalyst diffuse, and a gel may be formed. Therefore, it is preferable to add a solution obtained by dissolving the imidation agent and/or the dehydration catalyst in an organic solvent to the polyamic acid composition.

The polyimide film (specifically, the polyimide film containing the imidide of polyamic acid (1)) according to the present embodiment is colorless and transparent, has a low yellowness, and has a glass transition that can withstand the TFT fabrication process. Since it has temperature (heat resistance), it is suitable for the transparent substrate material of a flexible display. The content rate of the polyimide (more specifically, the imidide of polyamic acid (1)) in the polyimide film according to the present embodiment is, for example, 70% by weight or more, and 80% by weight relative to the total amount of the polyimide film. It is preferably more than that, more preferably 90% by weight or more, and 100% by weight may be sufficient. Examples of components other than the polyimide in the polyimide film include additives described later (more specifically, nanosilica particles and the like).

An electronic device according to this embodiment includes the polyimide film according to this embodiment and an electronic element disposed on the polyimide film. In the case of manufacturing the electronic device according to the present embodiment for a flexible display, first, a polyimide film is formed on an inorganic substrate such as glass as a support. And an electronic device is formed on a support body by arrange|positioning (forming) electronic elements, such as TFT, on a polyimide film. The process of forming a TFT is generally carried out in a wide temperature range of 150°C or more and 650°C or less. In some cases, a-Si or the like is crystallized by a laser or the like.

At this time, when the thermal decomposition temperature of the polyimide film is low, outgas is generated during the formation of the electronic element and adheres to the oven as a sublimated product, causing contamination in the furnace, or an inorganic film formed on the polyimide film (a barrier film described later). etc.) or electronic elements may peel off, so the 1% weight loss temperature of polyimide is preferably 500°C or higher. The higher the upper limit of the 1% weight loss temperature of polyimide, the better, but it is, for example, 520°C. The 1% weight loss temperature can be adjusted by, for example, changing the content of residues having a rigid structure (more specifically, TFMB residues, PMDA residues, BPDA residues, etc.). More specifically, an inorganic film such as a silicon oxide film (SiOx film) or a silicon nitride film (SiNx film) is formed as a barrier film on the polyimide film before forming the TFT. At this time, when the heat resistance of polyimide is low, when imidation is not completely progressed, or when there is a large amount of residual solvent, due to volatile components such as decomposition gas of polyimide in the high-temperature process after inorganic film lamination, polyimide and The inorganic film may peel off. For this reason, in addition to the 1% weight reduction temperature of polyimide being 500°C or higher, it is preferable that the weight reduction rate when isothermally maintaining the polyimide at a temperature within the range of 400°C or higher and 450°C or lower is less than 1%.

In the case where the glass transition temperature (Tg) of polyimide is significantly lower than the process temperature, misalignment or the like may occur during electronic element formation. Therefore, the Tg of polyimide is preferably 300°C or higher, and 350°C It is more preferable that it is above, and it is more preferable that it is 400 degreeC or more. The higher the upper limit of the Tg of polyimide, the better, but is, for example, 450°C. Also, since the coefficient of thermal expansion of a glass substrate is generally smaller than that of a resin, internal stress occurs between the glass substrate and the polyimide film. When the internal stress of a laminate of a glass substrate or electronic device used as a support and a polyimide film is high, the laminate containing the polyimide film expands in the high-temperature TFT formation step and then contracts when cooled to room temperature, resulting in the loss of the glass substrate. Problems such as warpage, breakage, and peeling of the polyimide film from the glass substrate occur. Therefore, the internal stress generated in the laminate of the polyimide film and the glass substrate is preferably 30 MPa or less, more preferably 25 MPa or less, and still more preferably 20 MPa or less.

The polyimide according to this embodiment can be suitably used as a material for display substrates such as TFT substrates and touch panel substrates. When polyimide is used for the above applications, a method of forming an electronic device (specifically, an electronic device in which electronic elements are formed on a polyimide film) on a support as described above, and then peeling the polyimide film from the support is adopted. often do Moreover, as a material of a support body, an alkali-free glass is used suitably. Hereinafter, an example of the manufacturing method of the laminated body of a polyimide film and a support body is demonstrated in detail.

First, a polyamic acid composition according to the present embodiment (preferably, a polyamic acid composition containing polyamic acid (1), a plasticizer and an organic solvent) is applied onto a support, and polyamic acid (1) and A coating film-containing laminate comprising a coating film containing a plasticizer and a support is formed. Next, the coating film-containing laminate is heated under conditions of, for example, a temperature of 40°C or higher and 200°C or lower. The heating time at this time is 3 minutes or more and 120 minutes or less, for example. Further, for example, a multi-step heating step may be provided, such as heating the coated film-containing laminate at a temperature of 50°C for 30 minutes and then heating at a temperature of 100°C for 30 minutes. Next, in order to advance the imidation of the polyamic acid (1) in the coating film, the coating film-containing laminate is heated under conditions of, for example, a maximum temperature of 200°C or more and 500°C or less. The heating time (heating time at the highest temperature) at this time is, for example, 1 minute or more and 300 minutes or less. At this time, it is preferable to gradually raise the temperature from the low temperature to the highest temperature. The temperature increase rate is preferably 2°C/min or more and 10°C/min or less, and more preferably 4°C/min or more and 10°C/min or less. Further, the maximum temperature is preferably in the range of 250°C or more and 450°C or less. When the maximum temperature is 250°C or higher, imidization proceeds sufficiently, and when the maximum temperature is 450°C or lower, thermal deterioration and coloring of the polyimide can be suppressed. Further, it may be held at any temperature for any length of time until reaching the maximum temperature. Although the imidation reaction can be performed under air, under reduced pressure, or in an inert gas such as nitrogen, in order to develop higher transparency, it is preferable to carry out under reduced pressure or in an inert gas such as nitrogen. In addition, as a heating apparatus, well-known apparatuses, such as a hot-air oven, an infrared oven, a vacuum oven, an inert oven, and a hot plate, can be used. Through these steps, the polyamic acid (1) in the coating film is imidized, and the laminate of the support and the polyimide film (film containing the imidide of polyamic acid (1)) (that is, in the present embodiment) related laminates) can be obtained. In addition, in order to shorten the heating time or develop characteristics, an imidation agent or a dehydration catalyst may be added to the polyamic acid composition, and the solution may be heated by the above method to imidize.

A well-known method can be used for the method of peeling a polyimide film from the laminated body of the obtained support body and polyimide film. For example, it may be removed by hand or may be removed using a mechanical device such as a driving roll or a robot. Furthermore, a method of providing a peeling layer between the support and the polyimide film, forming a silicon oxide film on a substrate having a large number of grooves, forming a polyimide film with the silicon oxide film as a base layer, and forming the substrate and the silicon oxide film It is also possible to adopt a method of peeling the polyimide film by infiltrating the silicon oxide etchant therebetween. Alternatively, a method of separating the polyimide film by irradiation with laser light may be employed.

If the interface between the polyimide film and the support (for example, glass substrate) is lifted, the polyimide film may be peeled off during the formation of the electronic element, or the yield may be lowered when the polyimide film is peeled after the electronic element is formed. there is In addition, "floating" refers to a material layer different from the polyimide film (more specifically, a glass substrate, a barrier film, etc. ) refers to a state in which poor adhesion has occurred between As specific "floating", a state in which the polyimide film was lifted from the glass substrate, a state in which a part of the polyimide film was destroyed and interlayer separation occurred between the polyimide film and another material layer, a state in which the barrier film was lifted from the polyimide film, etc. can be heard Since the polyamic acid composition according to the present embodiment can suppress the generation of hydrogen fluoride when the obtained polyimide is used in a high-temperature process, it can suppress the generation of floating.

Transparency of the polyimide film can be evaluated by total light transmittance (TT) according to JIS K7361-1:1997 and haze according to JIS K7136-2000. When using a polyimide film for a use requiring high transparency, the total light transmittance of the polyimide film is preferably 75% or more, and more preferably 80% or more. Further, when the polyimide film is used for applications requiring high transparency, the haze of the polyimide film is preferably 1.5% or less, more preferably 1.2% or less, still more preferably less than 1.0%, and may be 0%. In applications requiring high transparency, the polyimide film is required to have high transmittance in the entire wavelength range, but the polyimide film tends to absorb short wavelength light, and the film itself is often colored yellow. In order to use the polyimide film for applications requiring high transparency, it is preferable that the coloration of the polyimide film is reduced. Specifically, in order to use the polyimide film for applications requiring high transparency, the yellowness index (YI) of the polyimide film is preferably 20 or less, more preferably 18 or less, still more preferably 15 or less, and 12 or less. More preferably, it is particularly preferably 8 or less, and may be 0. YI can be measured according to JIS K7373-2006. YI can be adjusted by changing the content rate of the TFMB residue in polyamic acid (1), for example. In this way, the polyimide film with reduced coloring and imparted transparency is suitable for a transparent substrate for use as a substitute for glass or a substrate on which a sensor or camera module is provided on the back surface.

Further, there are two types of light extraction methods of flexible displays: a top emission method for extracting light from the TFT side and a bottom emission method for extracting light from the back side of the TFT. In the top emission method, since light is not blocked in the TFT, it is easy to increase the aperture ratio, and there is a feature that high-definition image quality is obtained. there is. If the TFT is transparent, it becomes possible to improve the aperture ratio even in the bottom emission method, so the bottom emission method, which is easy to manufacture, tends to be adopted for large-sized displays. Since the polyimide film according to the present embodiment has a low YI and excellent heat resistance, it can be applied to any of the light extraction methods described above.

Further, in a batch-type device fabrication process in which a polyamic acid composition is applied onto a support such as a glass substrate, heated to imidize, and an electronic element or the like is formed, and then the polyimide film is peeled off, the support and poly It is preferable that the adhesion between the mid films is excellent. Adhesion as used herein means adhesion strength. In the production process of forming the electronic element or the like on the polyimide film on the support and then peeling the polyimide film on which the electronic element or the like is formed from the support, when the adhesion between the polyimide film and the support is excellent, the electronic element or the like can be formed more accurately. It can be formed or mounted. In the manufacturing process of arranging an electronic element or the like on a support through a polyimide film, the higher the peel strength between the support and the polyimide film, the better, from the viewpoint of productivity improvement. Specifically, the peel strength is preferably 0.05 N/cm or more, and more preferably 0.1 N/cm or more.

In the manufacturing process as described above, when peeling the polyimide film from the laminate of the support and the polyimide film, the polyimide film is often peeled from the support by laser irradiation. In this case, since it is necessary to make the polyimide film absorb the laser beam, the cutoff wavelength of the polyimide film is required to be longer than the wavelength of the laser beam used for peeling. Since a XeCl excimer laser with a wavelength of 308 nm is often used for laser ablation, the cutoff wavelength of the polyimide film is preferably 312 nm or more, and more preferably 330 nm or more. On the other hand, since the polyimide film tends to be colored yellow when the cutoff wavelength is a long wavelength, the cutoff wavelength of the polyimide film is preferably 390 nm or less. From the viewpoint of achieving both transparency (low yellowness) and laser ablation processability, the cutoff wavelength of the polyimide film is preferably 320 nm or more and 390 nm or less, and more preferably 330 nm or more and 380 nm or less. In addition, the cutoff wavelength in this specification means the wavelength at which the transmittance|permeability measured by the ultraviolet-visible spectrophotometer becomes 0.1 % or less.

The polyamic acid composition and polyimide according to the present embodiment may be used as they are in coating or molding processes for producing products or members, but as materials for further processing such as coating on molded articles molded into films. can also be used For use in the coating or molding process, the polyamic acid composition or polyimide is dissolved or dispersed in an organic solvent, if necessary, and a photocurable component, thermosetting component, non-polymerizable binder resin and other components are added as necessary. It may be blended to prepare a composition containing polyamic acid (1) or polyimide.

In order to impart processing properties and various functionalities to the polyamic acid composition and polyimide according to the present embodiment, various organic or inorganic low-molecular compounds or high-molecular compounds may be blended as additives. As additives, dyes, surfactants, leveling agents, plasticizers, silicones, fine particles, sensitizers and the like can be used, for example. The fine particles include organic fine particles made of polystyrene, polytetrafluoroethylene, etc., inorganic fine particles made of colloidal silica, carbon, layered silicate, etc., and they may have a porous structure or a hollow structure. In addition, the function and shape of the fine particles are not particularly limited, and may be, for example, pigments, fillers, or fibrous particles.

In order to improve the heat resistance while maintaining the transparency of the polyimide film, nanosilica particles may be used as the additive, and the polyamic acid (1) and the nanosilica particles may be composited. From the viewpoint of maintaining the transparency of the polyimide film, the average primary particle diameter of the nanosilica particles is preferably 200 nm or less, more preferably 100 nm or less, still more preferably 50 nm or less, and may be 30 nm or less. On the other hand, from the viewpoint of securing the dispersibility to the polyamic acid (1), the average primary particle diameter of the nanosilica particles is preferably 5 nm or more, and more preferably 10 nm or more. As a method of compounding the polyamic acid (1) and the nanosilica particles, a known method can be used. For example, a method of using organosilica sol obtained by dispersing nanosilica particles in an organic solvent is exemplified. As a method of compounding polyamic acid (1) and nanosilica particles using organosilica sol, polyamic acid (1) is synthesized, and then the synthesized polyamic acid (1) and organosilica sol are mixed. Although a method may be used, it is preferable to synthesize the polyamic acid (1) in an organosilica sol in order to disperse the nanosilica particles in the polyamic acid (1) more highly.

Further, in order to enhance the interaction with the polyamic acid (1), the nanosilica particles may be surface-treated with a surface treatment agent. As a surface treatment agent, known things, such as a silane coupling agent, can be used. As a silane coupling agent, the alkoxysilane compound etc. which have an amino group or a glycidyl group etc. as a functional group are widely known, and can select suitably. In order to further enhance the interaction with the polyamic acid (1), an amino group-containing alkoxysilane is preferable as the silane coupling agent. Examples of the amino group-containing alkoxysilane include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, and 3-(2-aminoethyl). ) Aminopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 2-aminophenyltrimethoxysilane and 3-aminophenyltrimethoxysilane, etc. Preference is given to using propyltriethoxysilane. As a method of surface treatment of nanosilica particles, a method of stirring a mixture obtained by adding a silane coupling agent to a dispersion (organosilica sol) at an atmospheric temperature of 20°C or higher and 80°C or lower is exemplified. The stirring time at this time is 1 hour or more and 10 hours or less, for example. At this time, you may add a catalyst etc. which promote reaction.

The nano-silica-polyamic acid complex, in which polyamic acid (1) and nanosilica particles are combined, contains nano-silica particles with respect to 100 parts by weight of polyamic acid (1) within the range of 1 part by weight or more and 30 parts by weight or less. It is preferable to include, and it is more preferable to include within the range of 1 part by weight or more and 20 parts by weight or less. When the content of the nano-silica particles is 1 part by weight or more, the heat resistance of the polyimide containing nano-silica particles can be improved and the internal stress can be sufficiently reduced. Adverse effects on mechanical properties and transparency can be suppressed.

Imidazoles may be added to the polyamic acid composition according to the present embodiment as an additive for imparting the above-described functionality. In this specification, imidazole refers to a compound having a 1,3-diazole ring (1,3-diazole ring structure). The imidazoles added to the polyamic acid composition according to the present embodiment are not particularly limited, and examples thereof include 1H-imidazole, 2-methylimidazole, 2-undecylimidazole, and 2-heptane. Decylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methyl imidazole, 1-benzyl-2-phenylimidazole, etc. are mentioned. Among these, 1,2-dimethylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-phenylimidazole are preferable, and 1,2-dimethylimidazole and 1-benzyl -2-methylimidazole is more preferable.

The content of the imidazoles 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 still more preferably 0.015 mol or more and 0.050 mol or less with respect to 1 mol of the amide group of the polyamic acid (1). do. By containing 0.005 mol or more of imidazoles, the film strength and transparency of polyimide can be improved, and by making the content of imidazoles 0.1 mol or less, while maintaining the storage stability of polyamic acid (1), Tg and heat resistance are maintained. can improve To explain the improvement in transparency, it is known that a polymerization solvent such as NMP forms a complex with the carboxy group of polyamic acid (1) by hydrogen bonding, and when the imidation rate is slow, NMP or the like remains in the polyimide film. Therefore, oxidation or decomposition may cause coloration. When imidazoles are added, imidazoles coordinate with the carboxyl group of polyamic acid (1) to promote imidation, so NMP and the like are less likely to remain in the polyimide film, and at the same time, the thermal imidation process Since the decomposition of polyamic acid (1) is also suppressed, it is thought that transparency improves. According to the polyamic acid composition according to the present embodiment, since sufficient molecular motion is imparted at the time of imidation of the polyamic acid (1) by using a plasticizer, imidazoles do not need to be used in the present embodiment.

The mixing method of polyamic acid (1) and imidazoles is not particularly limited. From the viewpoint of the ease of controlling the molecular weight of the polyamic acid (1), it is preferable to add imidazoles to the polyamic acid (1) after polymerization. At this time, the imidazoles may be added directly to the polyamic acid (1), or the imidazoles may be dissolved in a solvent beforehand and the solution may be added to the polyamic acid (1), and the addition method is not particularly limited. . The polyamide acid composition according to the present embodiment may be prepared by adding an imidazole and a plasticizer to a solution containing the polyamic acid (1) after polymerization (solution after reaction).

In addition, the polyamic acid composition according to the present embodiment may contain a silane coupling agent in order to develop appropriate adhesion to the support. A known silane coupling agent can be used without particular limitation, but a compound containing an amino group is particularly preferred from the viewpoint of reactivity with the polyamic acid (1).

The mixing ratio of the silane coupling agent to 100 parts by weight of polyamic acid (1) is preferably 0.01 part by weight or more and 0.50 part by weight or less, more preferably 0.01 part by weight or more and 0.10 part by weight or less, and 0.01 part by weight or more and 0.05 part by weight. It is more preferable that it is less than a part. By setting the blending ratio of the silane coupling agent to 0.01 part by weight or more, the peeling inhibitory effect on the support is sufficiently exhibited, and by setting the blending ratio of the silane coupling agent to 0.50 part by weight or less, the molecular weight decrease of the polyamic acid (1) is suppressed. Therefore, embrittlement of the polyimide film can be suppressed.

Various inorganic thin films such as metal oxide thin films and transparent electrodes may be formed on the surface of the polyimide film according to the present embodiment. The method for forming these inorganic thin films is not particularly limited, and examples thereof include PVD methods such as sputtering, vacuum deposition, and ion plating, and CVD methods.

In addition to heat resistance, low thermal expansion, and transparency, the polyimide film according to the present embodiment has low internal stress generated when a laminate is formed with a glass substrate, and adhesion to inorganic materials can be secured during a high-temperature process. , it is preferred to be used in fields and products in which these properties are effective. For example, the polyimide film according to the present embodiment is used in image display devices such as liquid crystal display devices, organic EL and electronic paper, printed materials, color filters, flexible displays, optical films, 3D displays, touch panels, and transparent conductive film substrates. , solar cells, etc., and it is more preferable to use it as a substitute material for the part where glass is currently used. In these applications, the thickness of the polyimide film is, for example, 1 μm or more and 200 μm or less, and preferably 5 μm or more and 100 μm or less. The thickness of the polyimide film can be measured using a laser holo gauge.

In addition, the polyamic acid composition according to the present embodiment is a batch type device in which the polyimide film is peeled off after applying the polyamic acid composition on a support and imidizing it by heating to form an electronic element or the like. It can be used appropriately for the manufacturing process. Therefore, the present embodiment also includes a method for manufacturing an electronic device including a step of applying a polyamic acid composition on a support, imidizing it by heating, and forming an electronic element or the like in the polyimide film formed on the support. . Moreover, the manufacturing method of such an electronic device may further include the process of peeling the polyimide film in which the electronic element etc. were formed from the support body.

Example

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

<Method for measuring physical properties and evaluation method for adhesion>

First, a method for measuring the physical properties of polyimide (polyimide film) and a method for evaluating adhesion will be described.

[Yellowness Index (YI)]

For the polyimide film in each of the laminates obtained in Examples and Comparative Examples described later, the light transmittance at a wavelength of 200 nm or more and 800 nm or less was measured using a spectrophotometer (V-650 manufactured by Nippon Bunko Co., Ltd.). Then, the yellowness (YI) of the polyimide film was calculated from the formula described in JIS K7373-2006. When YI was 20 or less, it was evaluated that "coloration of the polyimide film can be reduced." On the other hand, when YI exceeded 20, it was evaluated as "not reducing the coloring of the polyimide film."

[Haze]

Regarding the polyimide film peeled from each laminate obtained in the examples and comparative examples described later, using an integrating sphere type haze meter ("HM-150N" manufactured by Murakami Shikisai Kijutsu Genkyujo Co., Ltd.), as described in JIS K7136-2000 Haze was measured by the method. When the haze was less than 1.0%, it was evaluated as "excellent in transparency". On the other hand, when the haze was 1.0% or more, it was evaluated as "not excellent in transparency".

[Internal Stress]

Each polyamic acid composition prepared in Examples and Comparative Examples described later was applied to a glass substrate (material: non-alkali glass, thickness: 0.7 mm, size: 100 mm × 100 mm) manufactured by Corning Co., whose warpage amount was measured in advance, using a spin coater. was applied, heated in air at 120°C for 30 minutes, and then heated at 430°C for 30 minutes in a nitrogen atmosphere to obtain a laminate comprising a polyimide film having a thickness of 10 µm on a glass substrate. In order to eliminate the effect of absorption of the polyimide film, after drying the laminate at 120 ° C. for 10 minutes, the amount of warping of the laminate in a nitrogen atmosphere at a temperature of 25 ° C. was measured using a thin film stress measuring device (“FLX- 2320-S”). Then, the internal stress generated between the glass substrate and the polyimide film was calculated by Stoney's equation from the amount of warp of the glass substrate before formation of the polyimide film and the amount of warp of the laminate.

[Glass Transition Temperature (Tg)]

A polyimide film sampled in a size of 3 mm in width and 10 mm in length from each laminate obtained in Examples and Comparative Examples described later was used as a sample for Tg measurement. Using a thermal analysis device (“TMA/SS7100” manufactured by Hitachi High-Tech Science Co., Ltd.), a load of 98.0 mN was applied to the sample, the temperature was raised from 20 ° C. to 450 ° C. at 10 ° C./min, and the temperature and strain amount (elongation) were plotted. TMA curves were obtained. The temperature of the inflection point of the obtained TMA curve (the temperature corresponding to the peak in the differential curve of the TMA curve) was taken as the glass transition temperature (Tg). When the Tg was 350°C or higher, it was evaluated as "excellent in heat resistance". On the other hand, when the Tg was less than 350°C, it was evaluated as "not excellent in heat resistance".

[1% Weight Loss Temperature (TD1)]

Each polyimide film (specifically, a polyimide film sampled from each laminate so that the weight is 10 mg) obtained in Examples and Comparative Examples described later is used as a sample for measurement, and a differential thermal thermogravimetric simultaneous measuring device (Hitachi Using "TG/DTA7200" manufactured by Hi-Tech Science Co., Ltd., the temperature was raised from 25 ° C. to 650 ° C. under the conditions of 20 ° C./min in a nitrogen atmosphere, and based on the sample weight at a measurement temperature of 150 ° C., the weight of this standard The measured temperature at the time of decreasing 1% by weight relative to 1% weight reduction temperature (TD1) was made.

[Presence or absence of lifting between the glass substrate and the polyimide film]

Each polyamic acid composition prepared in Examples and Comparative Examples described later was applied on a glass substrate (material: non-alkali glass, thickness: 0.7 mm, size: 100 mm × 100 mm) manufactured by Corning Corporation by a spin coater, and then in the air. After heating at 120°C for 30 minutes, it was heated at 430°C for 30 minutes in a nitrogen atmosphere to obtain a laminate comprising a polyimide film having a thickness of 10 µm on a glass substrate. About the obtained laminated body, the presence or absence of the floating between the glass substrate and the polyimide film|membrane was visually confirmed.

[Presence or absence of lifting between the SiOx film and the polyimide film]

Each polyamic acid composition prepared in Examples and Comparative Examples described later was applied on a glass substrate (material: non-alkali glass, thickness: 0.7 mm, size: 100 mm × 100 mm) manufactured by Corning Corporation by a spin coater, and then in the air. After heating at 120 ° C. for 30 minutes, heating at 430 ° C. for 30 minutes in a nitrogen atmosphere to form a polyimide film having a thickness of 10 μm on a glass substrate. Subsequently, a SiOx film (thickness: 1 µm) was laminated on the obtained polyimide film by plasma CVD, and the obtained laminate was heated under a nitrogen atmosphere under heating conditions shown in Table 4 described later. And about the laminated body after heating, the presence or absence of lifting between the SiOx film and the polyimide film was visually confirmed. In addition, the presence or absence of lifting between the SiOx film and the polyimide film was confirmed for Examples 1 to 18, Comparative Examples 1 to 5, and Comparative Example 10 described later.

[Analysis of Gas Generated from Polyimide Film]

Gas generated from the polyimide film during heating was analyzed using an analysis device in which a thermogravimetry device (“STA449 F5” manufactured by NETZSCH) and a quadrupole mass spectrometer (“JMS-Q1500GC” manufactured by Nippon Electronics Co., Ltd.) were combined. The analysis procedure will be described below.

First, the voltage of the quadrupole mass spectrometer was adjusted so that the peak detection intensity at m/z = 69 was 800,000 using perfluorotributylamine as a standard substance. Next, each polyimide film obtained in Examples and Comparative Examples described later (detailed More specifically, the polyimide film sampled from each laminate to have a mass of 140 mg) was heated and the gas generated from the polyimide film when the ambient temperature reached 470°C was analyzed with the quadrupole mass spectrometer. Further, by heating the polyimide film under a helium gas stream using the analyzer, the helium gas becomes a carrier gas, and the gas generated from the polyimide film can be analyzed in real time by the quadrupole mass spectrometer. Then, when the atmospheric temperature reached 470°C, the gas generated from the polyimide film was analyzed with the quadrupole mass spectrometer, and the peak detection intensity at m/z = 20 (20 peak intensity) was read from the obtained mass spectrum. When the 20 peak intensity was 60,000 or less, it was evaluated as "it is possible to suppress generation of hydrogen fluoride during a high-temperature process." On the other hand, when the 20 peak intensity exceeded 60,000, it was evaluated as "generation of hydrogen fluoride is not suppressed during the high-temperature process".

<Production of Polyimide Film>

Hereinafter, the manufacturing method of the polyimide film (laminate|laminate) of an Example and a comparative example is demonstrated. In addition, in the following, compounds and reagents are described with the following abbreviations. In addition, preparation of the polyamic acid solution used for preparation of a polyimide film was all performed in 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'-oxydianiline

TPP: Triphenylphosphate

TMP: Trimethylphosphate

DEPi: diethyl phosphite

TPPi: triphenylphosphite

PEP-36: 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane

3010: triisodecyl phosphite

PX-200: Resorcinol poly(di-2,6-xylyl)phosphate

CR-741: condensed phosphate ester (“CR-741” manufactured by Daihachi Chemical Industry Co., Ltd.)

DBA: dibutyl adipate

BXA-N: bis [2- (2-butoxyethoxy) ethyl] adipate

PEG600: polyethylene glycol (average molecular weight 560 to 640)

[Preparation of polyamic acid solution]

(Preparation of polyamic acid solution PA-2)

40.0 g of NMP was placed as an organic solvent for polymerization in a 300 mL glass separable flask equipped with a stirrer with a stainless steel stirrer and a nitrogen inlet tube. Then, while stirring the contents of the flask, 5.453 g of TFMB was added to the flask to dissolve. Next, after adding 2.439 g of PMDA, 0.788 g of BPAF, and 1.265 g of BPDA to the contents of the flask, the contents of the flask were stirred for 24 hours in an atmosphere at a temperature of 25°C to obtain polyamic acid solution PA-2.

(Preparation of polyamic acid solutions PA-1 and PA-3 to PA-10)

Polyamic acid solution PA- Polyamic acid solutions PA-1 and PA-3 to PA-10 were prepared by the same method as in 2, respectively. In addition, for any of the polyamic acid solutions PA-1 and PA-3 to PA-10, the total amount of acid dianhydride was the same as that of the polyamic acid solution PA-2.

In Table 1, "-" means that the component was not used. In addition, in Table 1, the numerical value of the "acid dianhydride" column is the content rate (unit: mol%) of each acid dianhydride with respect to the total amount of the acid dianhydride used. In Table 1, the numerical value of the "diamine" column is the content rate (unit: mol%) of each diamine with respect to the total amount of diamine used. In Table 1, "ratio" means the ratio of the total amount of diamine used to the total amount of acid dianhydride used (total amount of diamine/total amount of acid dianhydride). In addition, for any of the polyamic acid solutions PA-1 to PA-10, the mole fraction of each residue of the polyamic acid in the prepared polyamic acid solution is the respective monomers (diamine and tetracarb) used in the synthesis of the polyamic acid. boxylic acid dianhydride) was consistent with the mole fraction.

[Example 1]

Under a nitrogen atmosphere, TMP as a plasticizer was added to polyamic acid solution PA-1, and the resulting mixture was stirred for 5 minutes to obtain a polyamic acid composition. The addition amount of TMP was 1 part by weight with respect to 100 parts by weight of the polyamic acid in the polyamic acid solution PA-1. The obtained polyamic acid composition was coated on a glass substrate (manufactured by Corning, material: alkali-free glass, thickness: 0.7 mm, size: 100 mm × 100 mm) using a spin coater, and in air at 120 ° C. for 30 minutes. After heating, it heated at 430 degreeC for 30 minutes in nitrogen atmosphere, and obtained the laminated body provided with the polyimide film of thickness 10 micrometers on the glass substrate.

[Examples 2 to 20 and Comparative Examples 1 to 10]

A laminate comprising a polyimide film having a thickness of 10 μm on a glass substrate in the same manner as in Example 1, except that the type of polyamide acid solution used and the type and amount of plasticizer used were changed as shown in Table 2. got a sieve In Table 2, "-" means that no plasticizer was used. Therefore, in Comparative Examples 1 to 10, as polyamic acid compositions, polyamic acid solutions PA-1 to PA-10 were used, respectively. In Table 2, the addition amount of the plasticizer is the addition amount (unit: parts by weight) relative to 100 parts by weight of the polyamic acid in the polyamic acid solution used.

<Physical properties and evaluation results>

For each of Examples 1 to 20 and Comparative Examples 1 to 10, physical properties and evaluation results are shown in Tables 3 and 4. In Table 3, "-" means not measured. In Table 3, "the presence or absence of lifting between the glass substrate" is the presence or absence of lifting between the glass substrate and the polyimide film. In Table 4, "presence or absence of lifting between the SiOx film" is the presence or absence of lifting between the SiOx film and the polyimide film.

1, in Example 18 and Comparative Example 5, the gas generated from the polyimide film was analyzed with a quadrupole mass spectrometer according to the method described in [Analysis of the gas generated from the polyimide film], and the results obtained were indicate In Fig. 1, the vertical axis represents the detected intensity, and the horizontal axis represents the temperature (atmospheric temperature). 1, the solid line represents the change in peak detection intensity at m/z = 20 in Comparative Example 5, and the broken line represents the change in peak detection intensity at m/z = 20 in Example 18. indicate As shown in Fig. 1, Example 18 has a smaller peak detection intensity at m/z = 20 in the ambient temperature of 470 ° C. It was found that the occurrence can be suppressed.

As shown above, in Examples 1 to 20 using polyamic acid compositions containing a polyamic acid having structural unit (1) and a plasticizer, all conditions (1) to (6) below were 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 higher.

(5) TD1 is 500°C or higher.

(6) The 20 peak intensity is 60,000 or less.

In Comparative Examples 1 to 7, the 20 peak intensity exceeded 60,000. Therefore, in the polyimide films obtained in Comparative Examples 1 to 7, generation of hydrogen fluoride was not suppressed during the high-temperature process. In Comparative Examples 8 and 9, Tg was less than 350°C. Therefore, the polyimide films obtained in Comparative Examples 8 and 9 were not excellent in heat resistance. In Comparative Example 10, YI exceeded 20. Therefore, the coloration of the polyimide film obtained in Comparative Example 10 was not reduced.

From the above results, it was shown that the polyimide obtained from the polyamic acid composition according to the present invention is excellent in low colorability, transparency and heat resistance, and can suppress the generation of hydrogen fluoride during a high-temperature process.

Claims (14)

A polyamic acid composition containing a polyamic acid containing a structural unit represented by the following general formula (1), and a plasticizer.

(In the above general formula (1),
R ¹ and R ² each independently represent a hydrogen atom, a monovalent aliphatic group or a monovalent aromatic group;
X represents a tetravalent organic group.) The polyamic acid composition according to claim 1, wherein in the general formula (1), both R ¹ and R ² represent a hydrogen atom. According to claim 1 or 2, in the general formula (1), X is a tetravalent organic group represented by the following formula (2), a tetravalent organic group represented by the following formula (3), the following formula ( A polyamic acid composition comprising at least one member selected from the group consisting of a tetravalent organic group represented by 4) and a tetravalent organic group represented by the following formula (5).

The polyamide according to any one of claims 1 to 3, wherein the content of the structural unit represented by the general formula (1) is 50 mol% or more and 100 mol% or less with respect to all structural units of the polyamic acid. acid composition. The polyamic acid composition according to any one of claims 1 to 4, wherein the amount of the plasticizer is 20 parts by weight or less with respect to 100 parts by weight of the polyamic acid. The polyamic acid composition according to any one of claims 1 to 5, wherein the plasticizer is at least one selected from the group consisting of phosphorus-containing compounds, polyalkylene glycols, and aliphatic dibasic acid esters. The polyamic acid composition according to any one of claims 1 to 6, further containing an organic solvent. A polyimide which is an imide of the polyamic acid contained in the polyamic acid composition according to any one of claims 1 to 7. The polyimide according to claim 8, wherein the 1% weight loss temperature is 500°C or higher. A polyimide film comprising the polyimide according to claim 8 or 9. The polyimide film according to claim 10, having a yellowness of 20 or less. A laminate comprising a support and the polyimide film according to claim 10 or 11. As a method for producing a laminate having a support and a polyimide film,
A method for producing a laminate comprising applying the polyamic acid composition according to claim 7 onto a support to form a coating film containing the polyamic acid and the plasticizer, and imidizing the polyamic acid by heating the coating film. . An electronic device comprising the polyimide film according to claim 10 or 11 and an electronic element disposed on the polyimide film.

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