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

Abstract

The polyamide acid of the present application has a tetracarboxylic dianhydride residue and a diamine residue. The diamine residue includes a divalent organic group represented by the following general formula (1). The tetracarboxylic dianhydride residue includes one or more selected from the group consisting of a tetravalent organic group represented by the following chemical formula (2), a tetravalent organic group represented by the following chemical formula (3), a tetravalent organic group represented by the following chemical formula (4), a tetravalent organic group represented by the following chemical formula (5), a tetravalent organic group represented by the following chemical formula (6), a tetravalent organic group represented by the following chemical formula (7), a tetravalent organic group represented by the following chemical formula (8), a tetravalent organic group represented by the following chemical formula (9), and a tetravalent organic group represented by the following chemical formula (10).

Description

Technical Field

[0001] This invention relates to polyamic acid, polyamic acid compositions, polyimide, polyimide films, laminates, methods for manufacturing laminates, and electronic devices. Furthermore, this invention relates to electronic device materials using polyimide, thin-film transistor (TFT) substrates, flexible display substrates, color filters, printed materials, optical materials, image display devices (more specifically, liquid crystal displays, organic EL, electronic paper, etc.), 3D displays, solar cells, touch panels, transparent conductive film substrates, and alternative materials to currently used glass components. Background Technology

[0002] With the rapid development of displays such as liquid crystal displays (LCDs), organic EL displays (OLEDs), and electronic paper displays, as well as electronic devices such as solar cells and touch panels, there is continuous progress in making these devices thinner, lighter, and more flexible. In these devices, polyimide is being used instead of glass substrates as the substrate material.

[0003] These devices contain various electronic components, such as thin-film transistors or transparent electrodes, formed on a substrate. The formation of these electronic components requires high-temperature processes. Polyimide has sufficient heat resistance to withstand high-temperature processes, and its coefficient of thermal expansion (CTE) is close to that of glass substrates or electronic components. Therefore, it is not prone to internal stress and is suitable as a substrate material for flexible displays, etc.

[0004] Generally, aromatic polyimides are colored yellowish-brown due to the formation of intramolecular conjugation or charge transfer (CT) complexes. However, since light is extracted from the opposite side of the substrate in top-emitting organic EL and the like, the substrate is not required to be transparent, and the previous aromatic polyimides have been used. However, in cases where light emitted from the display element passes through the substrate and exits, such as in transparent displays, bottom-emitting organic ELs, and liquid crystal displays, or in cases where sensors and camera modules are placed on the back of the substrate to make full-screen displays (notchless) such as smartphones, the substrate is required to have high optical properties (more specifically, transparency, etc.).

[0005] Against this backdrop, there is a need for a material that possesses heat resistance comparable to existing aromatic polyimides, while exhibiting reduced coloring and excellent transparency.

[0006] It is known that techniques for using aliphatic monomers to suppress the formation of CT complexes in order to reduce the coloring of polyimide are known (Patent Documents 1 and 2), and techniques for improving transparency by using monomers with fluorine atoms are known (Patent Document 3).

[0007] Although the polyimide described in Patent Documents 1 and 2 has high transparency and low CTE, it has a low thermal decomposition temperature due to its aliphatic structure, making it difficult to apply to high-temperature processes in the formation of electronic components.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2016-29177

[0011] Patent Document 2: Japanese Patent Application Publication No. 2012-41530

[0012] Patent Document 3: Japanese Patent Application Publication No. 2014-70139 Summary of the Invention

[0013] The problem the invention aims to solve

[0014] Furthermore, through the research of the inventors, it has been determined that although the polyimide described in Patent Document 3 has excellent transparency, it may generate hydrogen fluoride during high-temperature processes due to the presence of fluorine atoms. If hydrogen fluoride is generated, it may lead to poor adhesion between the polyimide and the barrier membrane, or corrosion of electronic components disposed on the polyimide film.

[0015] This invention was made in view of the above-mentioned circumstances, and its object is to provide a polyimide that not only has excellent transparency but also suppresses the generation of hydrogen fluoride during high-temperature processes, and a polyamic acid as a precursor thereof. Furthermore, this invention also aims to provide an article or component requiring transparency manufactured using this polyimide and polyamic acid.

[0016] Solution for solving the problem

[0017] <Methods of the Invention>

[0018] The present invention includes the following methods.

[0019] [1] A polyamic acid having a tetracarboxylic dianhydride residue and a diamine residue.

[0020] The above-mentioned diamine residues contain divalent organic groups represented by the following general formula (1).

[0021] The aforementioned tetracarboxylic acid dianhydride residue comprises one or more of the following groups: tetravalent organic groups represented by chemical formula (2), tetravalent organic groups represented by chemical formula (3), tetravalent organic groups represented by chemical formula (4), tetravalent organic groups represented by chemical formula (5), tetravalent organic groups represented by chemical formula (6), tetravalent organic groups represented by chemical formula (7), tetravalent organic groups represented by chemical formula (8), tetravalent organic groups represented by chemical formula (9), and tetravalent organic groups represented by chemical formula (10).

[0022]

[0023] In the above general formula (1), R 1 and R 2 Each of the following can be independently represented as trifluoromethoxy, pentafluoroethoxy, or heptafluoropropoxy, where 'a' represents an integer greater than or equal to 1 and less than 4, and 'b' represents an integer greater than or equal to 0 and less than 4. When 'a' represents an integer greater than or equal to 2 and less than 4, multiple R... 1 Choose any two numbers that are the same or different from each other, where b represents an integer greater than 2 and less than 4, and multiple R's can be... 2 Choose any two numbers that are the same or different from each other, where n represents an integer greater than 0 and less than 3.

[0024] [2] The polyamic acid described in [1] above, wherein the tetracarboxylic acid dianhydride residue further comprises one or more of the group consisting of a tetravalent organic group represented by the following chemical formula (11), a tetravalent organic group represented by the following chemical formula (12) and a tetravalent organic group represented by the following chemical formula (13).

[0025]

[0026] [3] A polyamic acid composition comprising the polyamic acid as described in [1] or [2] above, and an organic solvent.

[0027] [4] The polyamic acid composition described in [3] above further contains one or more compounds selected from the group consisting of tertiary amines, phosphorus-containing compounds and phenolic compounds.

[0028] [5] The polyamic acid composition as described in [4] above, wherein the amount of one or more compounds selected from the group consisting of tertiary amines, phosphorus-containing compounds and phenolic compounds is 0.001 parts by weight or more and 20 parts by weight or less relative to 100 parts by weight of the polyamic acid.

[0029] [6] A polyimide which is an imide of the polyamic acid described in [1] or [2] above.

[0030] [7] The polyimide described in [6] above, wherein, under a helium gas flow, the polyimide is heated from an atmosphere temperature of 60°C to 500°C at a heating rate of 10°C / min, and the mass spectrum obtained by analyzing the gas generated by the polyimide using a quadrupole mass spectrometer, the value obtained by dividing the detection intensity of the peak at an atmosphere temperature of 450°C by the detection intensity of the peak at an atmosphere temperature of 100°C is 3.0 or less.

[0031] [8] A polyimide film comprising the polyimide described in [6] or [7] above.

[0032] [9] The polyimide film described above in [8] has a transmittance of more than 30% for light with a wavelength of 400 nm.

[0033]

[10] The polyimide film described in [8] or [9] above has a haze of less than 1.0%.

[0034]

[11] The polyimide film described in any of [8] to

[10] above has a yellowness of 15 or less.

[0035]

[12] A laminate having a support and a polyimide film as described in any one of [8] to

[11] above.

[0036]

[13] A method for manufacturing a laminate, which is a method for manufacturing a laminate having a support and a polyimide film.

[0037] By coating a support with a polyamic acid composition as described in any one of [3] to [5] above, a coating film containing the polyamic acid is formed, and the coating film is heated to imidize the polyamic acid.

[0038]

[14] An electronic device having a polyimide film as described in any one of [8] to

[11] above, and electronic components disposed on the polyimide film.

[0039] The effects of the invention

[0040] Polyimides manufactured using the polyamic acid of the present invention not only exhibit excellent transparency but also suppress the generation of hydrogen fluoride during high-temperature processes. Therefore, polyimides manufactured using the polyamic acid of the present invention are suitable as materials for electronic devices requiring transparency and manufactured via high-temperature processes. Detailed Implementation

[0041] The preferred embodiments of the present invention will be described in detail below, but the present invention is not limited thereto. Furthermore, all academic and patent documents described in this specification are incorporated herein by reference.

[0042] First, the terms used in this specification will be explained. “Structural unit” refers to a repeating unit that constitutes a polymer. “Polyamic acid” is a polymer that contains the structural unit represented by the following general formula (14) (hereinafter sometimes referred to as “structural unit (14)”).

[0043]

[0044] In general formula (14), A 1 Indicates a tetracarboxylic dianhydride residue (derived from a tetravalent organic group of tetracarboxylic dianhydride), A 2 It represents a diamine residue (a divalent organic group derived from a diamine).

[0045] The content of structural unit (14) relative to all structural units constituting 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 70 mol% or more and 100 mol% or less, even more preferably 80 mol% or more and 100 mol% or less, even more preferably 90 mol% or more and 100 mol% or less, and may also be 100 mol%.

[0046] “m / z” is a measured value that can be read from the horizontal axis of a mass spectrometer as a result of mass analysis. It refers to “the dimensionless quantity obtained by dividing the ion mass by a uniform atomic mass unit (Dalton) and then further dividing it by the absolute value of the ion’s charge number.”

[0047] Hereinafter, the term "system" will sometimes be added after the compound name to collectively refer to the compound and its derivatives. Additionally, when "system" is added after the compound name to indicate the polymer name, unless otherwise specified, it means that the repeating unit of the polymer originates from the compound or its derivatives. Furthermore, tetracarboxylic dianhydride is sometimes referred to as "acid dianhydride". Moreover, unless otherwise specified, the components or functional groups exemplified in this specification may be used alone or in combination of two or more.

[0048] <Preferred Embodiments of the Invention>

[0049] The polyamic acid of this embodiment (hereinafter, sometimes referred to as "specific polyamic acid") has tetracarboxylic acid dianhydride residues and diamine residues.

[0050] In a specific polyamic acid, the diamine residue comprises a divalent organic group represented by the general formula (1) below (hereinafter, sometimes referred to as "specific diamine residue"). That is, the specific polyamic acid comprises a specific diamine residue as a diamine residue. In addition, in a specific polyamic acid, the tetracarboxylic dianhydride residue comprises one or more residues selected from the group consisting of a tetravalent organic group represented by the chemical formula (2), a tetravalent organic group represented by the chemical formula (3), a tetravalent organic group represented by the chemical formula (4), a tetravalent organic group represented by the chemical formula (5), a tetravalent organic group represented by the chemical formula (6), a tetravalent organic group represented by the chemical formula (7), a tetravalent organic group represented by the chemical formula (8), a tetravalent organic group represented by the chemical formula (9), and a tetravalent organic group represented by the chemical formula (10) below (hereinafter, sometimes referred to as "specific acid dianhydride residue"). That is, the specific polyamic acid comprises a specific acid dianhydride residue as a tetracarboxylic dianhydride residue.

[0051]

[0052] In general formula (1), R 1 and R 2 Each of the following can be independently represented as trifluoromethoxy, pentafluoroethoxy, or heptafluoropropoxy, where 'a' represents an integer greater than or equal to 1 and less than 4, and 'b' represents an integer greater than or equal to 0 and less than 4. When 'a' represents an integer greater than or equal to 2 and less than 4, multiple R... 1 Choose any two numbers that are the same or different from each other, where b represents an integer greater than 2 and less than 4, and multiple R's can be... 2 The two numbers can be chosen to be the same or different, where n represents an integer greater than 0 and less than 3. It should be noted that in general formula (1), a and b can be chosen to be the same or different.

[0053] The tetravalent organic group represented by formula (2) is a partial structure (residue) derived from 2,3,3',4'-biphenyltetracarboxylic acid dianhydride (hereinafter, sometimes referred to as "a-BPDA"). The tetravalent organic group represented by formula (3) is a partial structure (residue) derived from 2,2',3,3'-biphenyltetracarboxylic acid dianhydride (hereinafter, sometimes referred to as "i-BPDA"). The tetravalent organic group represented by formula (4) is a partial structure (residue) derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (hereinafter, sometimes referred to as "BPAF"). The tetravalent organic group represented by formula (5) is a partial structure (residue) derived from spiro[11H-difurano[3,4-b:3',4'-i]xanthon-11,9'-[9H]fluorene]-1,3,7,9-tetraone (hereinafter, sometimes referred to as "SFDA"). The tetravalent organic group represented by formula (6) is a partial structure (residue) derived from 3,4'-oxophthalic anhydride (hereinafter sometimes referred to as "a-ODPA"). The tetravalent organic group represented by formula (7) is a partial structure (residue) derived from 4,4'-oxophthalic anhydride (hereinafter sometimes referred to as "ODPA"). The tetravalent organic group represented by formula (8) is a partial structure (residue) derived from decahydro-1H,3H-4,10:5,9-dimethylbridgednaphtho[2,3-c:6,7-c']difuran-1,3,6,8-tetraone (hereinafter sometimes referred to as "DNDA"). The tetravalent organic group represented by formula (9) is a partial structure (residue) derived from 5,5'-bis-2-norbornene-5,5',6,6'-tetracarboxylic acid-5,5',6,6'-dianhydride (hereinafter sometimes referred to as "BNBDA"). The tetravalent organic group represented by chemical formula (10) is a partial structure (residue) derived from norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid dianhydride (hereinafter sometimes referred to as "CpODA").

[0054] Polyimides made using specific polyamic acids not only exhibit excellent transparency but also suppress the generation of hydrogen fluoride during high-temperature processes. The reasons for this are speculated as follows.

[0055] Specific polyamic acids contain specific diamine residues including fluorine atoms and specific dianhydride residues that can inhibit the aggregation of polymer chains. Therefore, in polyimides manufactured using specific polyamic acids, the formation of CT complexes can be suppressed. Consequently, polyimides manufactured using specific polyamic acids exhibit excellent transparency.

[0056] Furthermore, in certain diamine residues, the fluoroalkyl group is bonded to the aromatic ring via an oxygen atom. Therefore, even when polyimides manufactured using specific polyamic acids are exposed to high temperatures, they are less prone to generating hydrogen fluoride. Thus, polyimides manufactured using specific polyamic acids can suppress the generation of hydrogen fluoride during high-temperature processes.

[0057] It should be noted that specific polyamic acids may also contain residues with a structure in which a fluoroalkyl group (e.g., trifluoromethyl, pentafluoroethyl, heptafluoropropyl, etc.) is directly bonded to a carbon atom (e.g., 2,2'-bis(trifluoromethyl)benzidine residues, 4,4'-(hexafluoroisopropylidene)phthalic anhydride residues, etc.), to a extent that does not impair their performance. However, in order to further suppress the generation of hydrogen fluoride in the high-temperature process, the content of residues with a structure in which a fluoroalkyl group is directly bonded to a carbon atom is preferably 0.1% by weight or less, more preferably 0.01% by weight or less, relative to the total amount (100% by weight) of the specific polyamic acid. In order to further suppress the generation of hydrogen fluoride in the high-temperature process, the specific polyamic acid is preferably a polyamic acid that does not contain residues with a structure in which a fluoroalkyl group is directly bonded to a carbon atom.

[0058] In order to further suppress the generation of hydrogen fluoride in the high-temperature process, R in general formula (1) 1 and R 2 Preferably, it represents trifluoromethoxy. In order to further suppress the generation of hydrogen fluoride in the high-temperature process, a in general formula (1) is preferably 1 or 2, more preferably 1. In order to further suppress the generation of hydrogen fluoride in the high-temperature process, b in general formula (1) is preferably an integer of 0 or more and 2 or less, more preferably 0 or 1.

[0059] In order to improve the solubility of a particular polyamic acid in an organic solvent and reduce the CTE of the obtained polyimide, n in general formula (1) is preferably 1 or 2, more preferably 1.

[0060] In order to obtain a polyimide that not only has better transparency but also can further suppress the generation of hydrogen fluoride in high-temperature processes, the specific diamine residue is preferably selected from one or more residues derived from 2,2'-bis(trifluoromethoxy)benzidine (hereinafter, sometimes referred to as "TFMOB"), residues derived from 3,3'-bis(trifluoromethoxy)benzidine, and residues derived from 2,3'-bis(trifluoromethoxy)benzidine, and more preferably TFMOB residues.

[0061] Certain polyamic acids containing specific diamine residues exhibit excellent solubility due to the presence of fluorine. Furthermore, by imparting photosensitivity to specific polyamic acids, they can also be used in patterning materials and materials requiring planarization properties.

[0062] When synthesizing a specific polyamic acid, other diamine monomers (other diamines) besides the diamine used to form a specific diamine residue can also be used. Other diamines include, for example, p-phenylenediamine, 1,3-bis(3-aminopropyl)tetramethyldisiloxane, 9,9-bis(4-aminophenyl)fluorene, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminobenzoylaniline, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, N,N'-bis(4-aminophenyl)terephthalamide, meta-toluidine, o-toluidine, 4,4'-bis(4-aminophenoxy)biphenyl, 2-(4-aminophenyl)-6-aminobenzoxazole, 3,5-diaminobenzoic acid, 4,4'-diamino-3,3'-dihydroxybiphenyl, 4,4'-methylenebis(cyclohexylamine), and their derivatives, which may be used alone or in combination.

[0063] In order to obtain polyimide with better transparency, the content of specific diamine residues is preferably 50 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more, and may also be 100 mol% relative to the total amount of diamine residues constituting the specific polyamic acid (100 mol%).

[0064] In order to obtain polyimide with better transparency, the specific acid dianhydride residue is preferably selected from one or more residues in the group consisting of α-BPDA residue, i-BPDA residue, BPAF residue and SFDA residue, and more preferably from one or more residues in the group consisting of α-BPDA residue, BPAF residue and SFDA residue.

[0065] To obtain polyimides with excellent heat resistance and transparency, one or more residues from the group consisting of BPAF residues and SFDA residues are preferably selected as the specific acid dianhydride residues. To improve the solubility of a specific polyamic acid and obtain polyimides with excellent heat resistance, one or more residues from the group consisting of α-BPDA residues and i-BPDA residues are preferably selected as the specific acid dianhydride residues. To obtain polyimides with excellent mechanical properties, one or more residues from the group consisting of α-ODPA residues and ODPA residues are preferably selected as the specific acid dianhydride residues. To further inhibit the formation of CT complexes, one or more residues from the group consisting of DNDA residues, BNBDA residues, and CpODA residues are preferably selected as the specific acid dianhydride residues.

[0066] In the synthesis of a specific polyamic acid, other dianhydride monomers (other dianhydrides) besides those used to form the specific dianhydride residues may also be used. Examples of other dianhydrides include, for example: pyromellitic dianhydride (hereinafter, sometimes referred to as "PMDA"), 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (hereinafter, sometimes referred to as "s-BPDA"), 2,3,6,7-naphthalenetetracarboxylic acid dianhydride (hereinafter, sometimes referred to as "NTCDA"), 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, p-phenylene bis(triphenylene trioxide), 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, and their derivatives. These may be used alone or in combination.

[0067] In order to obtain a polyimide with excellent heat resistance and reduced CTE by combining with specific diamine residues, the other acid dianhydride residues are preferably selected from the group consisting of s-BPDA residues, NTCDA residues, and PMDA residues, and more preferably from the group consisting of s-BPDA residues and NTCDA residues. Furthermore, when forming the polyimide film described below, in order to reduce the internal stress between the support and the polyimide film, the other acid dianhydride residues are preferably NTCDA residues. It should be noted that s-BPDA residues are tetravalent organic groups represented by the following chemical formula (11). Additionally, NTCDA residues are tetravalent organic groups represented by the following chemical formula (12). Furthermore, PMDA residues are tetravalent organic groups represented by the following chemical formula (13).

[0068]

[0069] In order to obtain polyimide with better transparency, the content of specific acid dianhydride residues (or their total content when multiple specific acid dianhydride residues are used) is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more, and may also be 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, or 80 mol% or more, or may be 100 mol%.

[0070] When a specific polyamic acid has α-BPDA residues as dianhydride residues of a specific acid, in order to obtain a polyimide with better transparency, the content of α-BPDA residues relative to the total amount (100 mol%) of tetracarboxylic acid dianhydride residues constituting the specific polyamic acid is preferably 10 mol% or more and 50 mol% or less, more preferably 20 mol% or more and 40 mol% or less.

[0071] When a specific polyamic acid has i-BPDA residues as specific acid dianhydride residues, in order to obtain a polyimide with better transparency, the content of i-BPDA residues relative to the total amount (100 mol%) of tetracarboxylic acid dianhydride residues constituting the specific polyamic acid is preferably 10 mol% or more and 50 mol% or less, more preferably 20 mol% or more and 40 mol% or less.

[0072] When a specific polyamic acid has BPAF residues as dianhydride residues, in order to obtain a polyimide with better transparency, the content of BPAF residues relative to the total amount (100 mol%) of tetracarboxylic acid dianhydride residues constituting the specific polyamic acid is preferably 5 mol% or more and 100 mol% or less, more preferably 10 mol% or more and 100 mol% or less.

[0073] When a specific polyamic acid has SFDA residues as specific acid dianhydride residues, in order to obtain a polyimide with better transparency, the content of SFDA residues relative to the total amount (100 mol%) of tetracarboxylic acid dianhydride residues constituting the specific polyamic acid is preferably 5 mol% to 100 mol% or less, more preferably 10 mol% to 100 mol% or less, further preferably 20 mol% to 100 mol% or less, and even more preferably 30 mol% to 100 mol% or less.

[0074] In order to obtain polyimides with better heat resistance and further reduced CTE, the content of one or more residues selected from the group consisting of s-BPDA residues, NTCDA residues and PMDA residues is preferably 10 mol% to 95 mol% relative to the total amount (100 mol%) of tetracarboxylic dianhydride residues constituting the specific polyamic acid, more preferably 20 mol% to 90 mol%, more preferably 30 mol% to 90 mol%, and more preferably 40 mol% to 85 mol%.

[0075] In order to obtain polyimide with better heat resistance, the content of s-BPDA residues relative to the total amount (100 mol%) of tetracarboxylic acid dianhydride residues constituting the specific polyamic acid is preferably 10 mol% or more and 95 mol% or less, more preferably 20 mol% or more and 90 mol% or less, more preferably 30 mol% or more and 90 mol% or less, and more preferably 40 mol% or more and 85 mol% or less.

[0076] In order to obtain a polyimide that can further reduce internal stress, the content of NTCDA residues relative to the total amount (100 mol%) of tetracarboxylic acid dianhydride residues constituting a specific polyamic acid is preferably 5 mol% to 75 mol%, more preferably 10 mol% to 70 mol%, and even more preferably 15 mol% to 60 mol%, but may also be 20 mol% to 60 mol%, 25 mol% to 60 mol%, 30 mol% to 60 mol%, 35 mol% to 60 mol%, or 40 mol% to 60 mol%.

[0077] When a specific polyamic acid has one or more residues selected from the group consisting of s-BPDA residues, NTCDA residues, and PMDA residues, in order to obtain a polyimide with better transparency and heat resistance and to further reduce CTE, the total content of the specific acid dianhydride residues, s-BPDA residues, NTCDA residues, and PMDA residues relative to the total amount (100 mol%) of the tetracarboxylic acid dianhydride residues constituting the specific polyamic acid is preferably 60 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more, and may also be 100 mol%.

[0078] To obtain a polyimide that not only exhibits superior transparency but also further suppresses the generation of hydrogen fluoride during high-temperature processes, the specific polyamic acid preferably satisfies condition 1 below. Furthermore, to obtain a polyimide that not only exhibits superior transparency and heat resistance but also further suppresses the generation of hydrogen fluoride during high-temperature processes, the specific polyamic acid preferably satisfies conditions 1 and 2 below. Additionally, to obtain a polyimide that reduces internal stress and not only exhibits superior transparency but also further suppresses the generation of hydrogen fluoride during high-temperature processes, the specific polyamic acid preferably satisfies conditions 1 and 3 below.

[0079] Condition 1: The content of specific acid dianhydride residues (or their total content when multiple specific acid dianhydride residues are used) is 5 mol% or more relative to the total amount (100 mol%) of tetracarboxylic acid dianhydride residues constituting the specific polyamic acid, and the content of specific diamine residues is 50 mol% or more relative to the total amount (100 mol%) of diamine residues constituting the specific polyamic acid.

[0080] Condition 2: The specific polyamic acid has s-BPDA residues, and the content of s-BPDA residues is more than 10 mol% and less than 95 mol% relative to the total amount (100 mol%) of tetracarboxylic dianhydride residues constituting the specific polyamic acid.

[0081] Condition 3: The specific polyamic acid has NTCDA residues, and the content of NTCDA residues is more than 5 mol% and less than 75 mol% relative to the total amount (100 mol%) of tetracarboxylic acid dianhydride residues constituting the specific polyamic acid.

[0082] Specific polyamic acids can be synthesized by known general methods, such as by reacting a diamine with a tetracarboxylic dianhydride in an organic solvent. An example of a specific synthetic method for a particular polyamic acid will be described. First, a diamine solution is prepared by dissolving or dispersing the diamine in an organic solvent in an inert gas atmosphere such as argon or nitrogen. Then, the tetracarboxylic dianhydride, either dissolved or dispersed in the organic solvent, or in a solid state, is added to the diamine solution.

[0083] When synthesizing a specific polyamic acid using diamines and tetracarboxylic dianhydrides, the desired specific polyamic acid (a polymer of diamine and tetracarboxylic dianhydride) can be obtained by adjusting the amount of diamine (or the amount of each diamine when using multiple diamines) and the amount of tetracarboxylic dianhydride (or the amount of each tetracarboxylic dianhydride when using multiple tetracarboxylic dianhydrides). The molar fraction of each residue in the specific polyamic acid is, for example, consistent with the molar fraction of each monomer used in the synthesis of the specific polyamic acid (each monomer corresponding to each residue). Furthermore, by blending two polyamic acids, a specific polyamic acid containing multiple tetracarboxylic dianhydride residues and multiple diamine residues can also be obtained. The temperature conditions for the reaction of the diamine with the tetracarboxylic dianhydride, i.e., the synthesis reaction of the specific polyamic acid, are not particularly limited, but are, for example, in the range of 20°C to 150°C. The reaction time for the synthesis reaction of the specific polyamic acid is, for example, in the range of 10 minutes to 30 hours.

[0084] The organic solvent used in the synthesis of a specific polyamic acid is preferably a solvent capable of dissolving the tetracarboxylic acid dianhydride and diamine used, and more preferably a solvent capable of dissolving the specific polyamic acid to be generated. Organic solvents used in the synthesis of specific polyamic acids include, for example: urea solvents such as tetramethylurea and N,N-dimethylethylurea; sulfoxide solvents such as dimethyl sulfoxide; sulfone solvents such as diphenyl sulfone and tetramethyl sulfone; amide solvents such as N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 3-methoxy-N,N-dimethylpropionamide (MPA), and hexamethylphosphoric triamine; ester solvents such as γ-butyrolactone; haloalkyl solvents such as chloroform and dichloromethane; aromatic hydrocarbon solvents such as benzene and toluene; phenol solvents such as phenol and cresol; ketone solvents such as cyclopentanone; and ether solvents such as tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, dimethyl ether, diethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, and p-cresol methyl ether. These solvents are typically used alone, but two or more may be used in combination as needed. To improve the solubility and reactivity of a specific polyamic acid, the organic solvent used in the synthesis reaction of the specific polyamic acid is preferably one or more solvents selected from the group consisting of amide solvents, ketone solvents, ester solvents, and ether solvents, more preferably amide solvents (more specifically, DMF, DMAC, NMP, MPA, etc.). Furthermore, the synthesis reaction of the specific polyamic acid is preferably carried out under an inert gas atmosphere such as argon or nitrogen.

[0085] The weight-average molecular weight of a specific polyamic acid depends on its application, and is preferably in the range of 10,000 to 1,000,000, more preferably in the range of 20,000 to 500,000, and even more preferably in the range of 30,000 to 200,000. If the weight-average molecular weight is 10,000 or higher, it is easy to form a coated film or polyimide film from the specific polyamic acid or polyimide obtained using the specific polyamic acid. On the other hand, if the weight-average molecular weight is 1,000,000 or lower, it exhibits sufficient solubility in solvents, and therefore a coated film or polyimide film with a smooth surface and uniform thickness can be obtained using the following polyamic acid compositions. The weight-average molecular weight used herein refers to the polyethylene oxide equivalent value measured using gel permeation chromatography (GPC).

[0086] Furthermore, as a method for controlling the molecular weight of a specific polyamic acid, examples include using an excess of either the dianhydride or the diamine, or quenching the reaction by reacting it with a monofunctional anhydride or amine such as phthalic anhydride or aniline. When polymerization is carried out in excess of either the dianhydride or the diamine, a polyimide film with sufficient strength can be obtained if their molar ratio is between 0.95 and 1.05. It should be noted that the above molar ratio is the ratio of the total amount of diamine used in the synthesis of the specific polyamic acid to the total amount of dianhydride used in the synthesis of the specific polyamic acid (total amount of diamine / total amount of dianhydride). Additionally, by using phthalic anhydride, maleic anhydride, aniline, etc. for end-capping, the coloring of the polyimide obtained using the specific polyamic acid can be further reduced.

[0087] The polyamic acid composition of this embodiment contains a specific polyamic acid and an organic solvent. Examples of organic solvents included in the polyamic acid composition include those capable of being used in the synthesis reaction of the specific polyamic acid described above. Preferably, it is a solvent selected from the group consisting of amide solvents, ketone solvents, ester solvents, and ether solvents, and more preferably an amide solvent (more specifically, DMF, DMAC, NMP, MPA, etc.). When the specific polyamic acid is obtained by the above method, the reaction solution (the solution after the reaction) itself may also be used as the polyamic acid composition of this embodiment. Alternatively, the specific polyamic acid obtained by removing the solvent from the reaction solution may be dissolved in an organic solvent to prepare the polyamic acid composition of this embodiment. It should be noted that the content of the specific polyamic acid in the polyamic acid composition of this embodiment is not particularly limited, for example, it is 1% by weight or more and 80% by weight or less relative to the total amount of the polyamic acid composition.

[0088] The polyamic acid composition of this embodiment may further contain one or more compounds selected from the group consisting of tertiary amines, phosphorus-containing compounds, and phenolic compounds (hereinafter sometimes referred to as "specific additives"). In this specification, specific additives are compounds different from polyamic acid and solvents. If the polyamic acid composition of this embodiment contains specific additives, sufficient molecular mobility is imparted to the specific polyamic acid during imidization. As a result, the imidization of the specific polyamic acid proceeds rapidly, and the depolymerization of the specific polyamic acid is also suppressed, further suppressing the generation of gas release (especially hydrogen fluoride). To further improve the molecular mobility of the specific polyamic acid during imidization, one or more compounds selected from the group consisting of tertiary amines and phosphorus-containing compounds are preferably used as specific additives.

[0089] To further improve the molecular mobility of a specific polyamic acid during imidization, a compound with a molecular weight of 1500 or less is preferably used as a specific additive. To further improve the molecular mobility of a specific polyamic acid during imidization, a compound soluble in an organic solvent in the polyamic acid composition is preferably used as a specific additive.

[0090] Furthermore, to further improve the molecular mobility of the specific polyamic acid during imidization, the preferred additive is a compound with a boiling point of 150°C or higher, more preferably a compound with a boiling point of 200°C or higher, and even more preferably a compound with a boiling point of 250°C or higher. To further improve the molecular mobility of the specific polyamic acid during imidization, the preferred additive is a compound that does not have a decomposition temperature in a temperature range below its boiling point. To further improve the molecular mobility of the specific polyamic acid during imidization, the boiling point of the additive is preferably higher than the boiling point of the organic solvent in the polyamic acid composition.

[0091] In order to further improve the molecular mobility of the specific polyamic acid during imidization and to suppress the decline in the properties of the polyimide due to the decomposition of the specific additive, the content of the specific additive relative to 100 parts by weight is preferably 0.001 parts by weight or more and 20 parts by weight or less, more preferably 0.01 parts by weight or more and 15 parts by weight or less, and even more preferably 0.1 parts by weight or more and 10 parts by weight or less.

[0092] The method of mixing the specific polyamic acid with the specific additive is not particularly limited. However, from the viewpoint of ease of controlling the molecular weight of the specific polyamic acid, it is preferable to add the specific additive to the polymerized specific polyamic acid. In this case, the specific additive can be added directly to the specific polyamic acid, or the specific additive can be dissolved in a solvent beforehand and then added to the specific polyamic acid; the method of addition is not particularly limited. Alternatively, the specific additive can be added to a polymerized solution containing the specific polyamic acid (the solution after the reaction) to prepare the polyamic acid composition of this embodiment.

[0093] Tertiary amines used as specific additives also function as imidization promoters due to their coordination with the carboxyl groups of specific polyamic acids. By including 0.001 parts by weight or more of a tertiary amine relative to 100 parts by weight of a specific polyamic acid, the strength and transparency of the obtained polyimide film can be improved, and the CTE of the obtained polyimide film can be reduced. Examples of tertiary amines include alkylamine compounds such as triethylamine, diisopropylamine, dibutylamine, and N,N-dimethylbutylamine; and heterocyclic compounds such as pyridine, 3,5-dimethylpyridine, and imidazole compounds.

[0094] In particular, imidazole compounds readily coordinate with the carboxyl groups of specific polyamic acids, thus the imidization of these acids proceeds more rapidly when used as tertiary amines. Consequently, during thermal imidization, organic solvents such as NMP are less likely to remain in the polyimide film, and the decomposition of the specific polyamic acid is also suppressed, leading to improved transparency of the resulting polyimide film.

[0095] It should be noted that, in this specification, imidazole compounds refer to compounds having a 1,3-diazole ring (1,3-diazole ring structure). There are no particular limitations on the imidazole compounds that can be added to the polyamic acid composition of this embodiment; examples include: 1H-imidazolium, 2-methylimidazolium, 2-undecylimidazolium, 2-heptadecylimidazolium, 1,2-dimethylimidazolium, 2-ethyl-4-methylimidazolium, 2-phenylimidazolium, 2-phenyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, 1-benzyl-2-phenylimidazolium, etc. Among these, 2-phenylimidazolium, 1,2-dimethylimidazolium, 1-benzyl-2-methylimidazolium, and 1-benzyl-2-phenylimidazolium are preferred, and more preferably 2-phenylimidazolium, 1,2-dimethylimidazolium, and 1-benzyl-2-methylimidazolium.

[0096] Examples of phosphorus-containing compounds include those represented by the general formulas (15-1) to (15-10). In the general formulas (15-1) to (15-10), R 5 R 6 and R 7 Each can independently represent a hydrogen atom, a monovalent organic group, or a polyvalent organic group, R 8 denoted by , m represents the degree of polymerization.

[0097]

[0098] Preferred examples of phosphorus-containing compounds include: phosphoric acid compounds, phosphite compounds, phosphonic acid compounds, hypophosphonic acid compounds, phosphine compounds, phosphine oxide compounds, phosphine compounds, and phosphazene compounds. Phosphorus-containing compounds may also be esters or condensates of the compounds listed above, may contain cyclic structures, and may form salts with amines, etc. Furthermore, among these phosphorus-containing compounds, there are also those that are tautomers, such as phosphite compounds and phosphonic acid compounds, and can exist in any state.

[0099] Specific examples of phosphoric acid compounds include: trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, tri(xylene) phosphate, tri(isopropylphenyl) phosphate, trinaphthalene phosphate, toluene diphenyl phosphate, xylene diphenyl phosphate, diphenyl(2-ethylhexyl) phosphate, di(isopropylphenyl) phosphate, monoisodecyl phosphate, acid 2-acryloyloxyethyl phosphate, acid 2-methacryloyloxyethyl phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, melamine phosphate, bis(melamine) phosphate, bisphenol A bis(diphenyl phosphate), tri(β-chloropropyl) phosphate, etc.

[0100] Specific examples of phosphite compounds include: triphenyl phosphite, tri(nonylphenyl) phosphite, tricresyl phosphite, triethyl phosphite, triisobutyl phosphite, tri(2-ethylhexyl) phosphite, tridecyl phosphite, trilauryl phosphite, tri(tridecyl) phosphite, diphenyl phosphite, diethyl phosphite, dibutyl phosphite, dimethyl phosphite, diphenylmono(2-ethylhexyl) phosphite, diphenylmonodecyl phosphite, diphenylmono(tridecyl) phosphite, trithiotrilauryl phosphite, diethyl hydrogen phosphite, bis(2-ethylhexyl) hydrogen phosphite, dilauryl hydrogen phosphite, and dioleyl hydrogen phosphite. Phosphite), diphenyl hydrogen phosphite, tetraphenyl dipropylene glycol diphosphite, bis(decyl) pentaerythritol diphosphite, bis(tetrazyl) pentaerythritol diphosphite, tristearate phosphite, distearate pentaerythritol 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-diphosspiro[5.5]undecane, etc.

[0101] Examples of the aforementioned condensates include condensed phosphate esters. Specific examples of condensed phosphate esters include: trialkyl polyphosphate, resorcinol polyphenyl phosphate, resorcinol poly(di-2,6-xylyl) phosphate, and hydroquinone poly(2,6-xylyl) phosphate. Commercially available condensed phosphate esters include, for example, "CR-733S" manufactured by Daihachi Chemical Industry Co., Ltd., "CR-741" manufactured by Daihachi Chemical Industry Co., Ltd., "PX-200" manufactured by Daihachi Chemical Industry Co., Ltd., and "FP-600" manufactured by ADEKA Co., Ltd.

[0102] Specific examples of phosphazene compounds include: phenoxycyclophosphonitrile ("FP-110" manufactured by Fushimi Pharmaceutical Co., Ltd.) and cyclic cyanophenoxyphosphonitrile ("FP-300" manufactured by Fushimi Pharmaceutical Co., Ltd.).

[0103] As phenolic compounds, examples include hindered, semi-hindered, and less hindered types. Specifically, examples include butylated hydroxytoluene, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylmethyl)-2,4,6-trimethylbenzene, and 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl) acrylate.

[0104] Phenolic compounds also function as primary antioxidants, scavenging peroxide free radicals and converting them into hydroperoxides, thus inhibiting the auto-oxidation of polymers. Therefore, phenolic compounds also possess the function of inhibiting coloring caused by polymer oxidation. Furthermore, by combining phenolic compounds with phosphites or similar secondary antioxidants that convert hydroperoxides into stable alcohol compounds, coloring caused by polyimide oxidation can be further inhibited. For example, by using phosphites in a range of 1 to 10 equivalents relative to phenolic compounds, coloring of polyimides can be effectively inhibited.

[0105] In addition, the polyamic acid composition of this embodiment may also contain an imidization accelerator and / or a dehydration catalyst in order to shorten the heating time or improve performance.

[0106] There are no particular limitations on the imidization promoters mentioned above, and tertiary amines can be used. Heterocyclic tertiary amines are preferred. Specific examples of preferred heterocyclic tertiary amines include pyridine, methylpyridine, quinoline, isoquinoline, and imidazole compounds. Specific examples of preferred dehydration catalysts include acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride.

[0107] The amount of imidization accelerator added, relative to the amide group of a specific polyamic acid, is preferably 0.5 to 5.0 molar equivalents, more preferably 0.7 to 2.5 molar equivalents, and even more preferably 0.8 to 2.0 molar equivalents. Furthermore, the amount of dehydration catalyst added, relative to the amide group of a specific polyamic acid, is preferably 0.5 to 10.0 molar equivalents, more preferably 0.7 to 5.0 molar equivalents, and even more preferably 0.8 to 3.0 molar equivalents. It should be noted that, in this specification, the term "amide group of a specific polyamic acid" refers to the amide group generated by the polymerization reaction of a diamine and a tetracarboxylic dianhydride. When adding the imidization accelerator and / or dehydration catalyst to the polyamic acid composition, it may be added directly without dissolving in an organic solvent, or it may be added if dissolved in an organic solvent. In methods where the polyamic acid is added directly without dissolving it in an organic solvent, a gel may sometimes form due to the rapid reaction before the imidization accelerator and / or dehydration catalyst diffuse. Therefore, it is preferable to add a solution obtained by dissolving the imidization accelerator and / or dehydration catalyst in an organic solvent to the polyamic acid composition.

[0108] In the polyamic acid composition of this embodiment, various organic or inorganic low-molecular-weight compounds or high-molecular-weight compounds may also be incorporated as additives different from the specific additives mentioned above. Examples of additives different from the specific additives include plasticizers, antioxidants, dyes, surfactants, leveling agents, silicones, microparticles, sensitizers, etc. Microparticles include organic microparticles formed from polystyrene, polytetrafluoroethylene, etc., and inorganic microparticles formed from colloidal silica, carbon, layered silicates, etc., which may have porous or hollow structures. Furthermore, the function and morphology of the microparticles are not particularly limited; for example, they may be pigments, fillers, or fibrous particles.

[0109] To maintain the transparency of the obtained polyimide film and improve its heat resistance, nano-silica particles can be used as the aforementioned additive, and a specific polyamic acid can be composited with the nano-silica particles. From the viewpoint of further improving the transparency of the polyimide film, the average primary particle size of the nano-silica particles is preferably 200 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less, and may also be 30 nm or less. On the other hand, from the viewpoint of ensuring dispersibility in the specific polyamic acid, the average primary particle size of the nano-silica particles is preferably 5 nm or more, more preferably 10 nm or more. As a method for composited with the specific polyamic acid and nano-silica particles, known methods can be used, such as the method of using an organosilicon sol formed by dispersing nano-silica particles in an organic solvent. As a method for combining a specific polyamic acid with nano-silica particles using an organosilicon sol, a method can also be used to synthesize the specific polyamic acid and then mix the synthesized specific polyamic acid with an organosilicon sol. However, in order to further disperse the nano-silica particles in the specific polyamic acid, it is preferable to synthesize the specific polyamic acid in an organosilicon sol.

[0110] In addition, to improve the interaction with specific polyamic acids, the nano-silica particles can be surface-treated with a surface treatment agent. Known surface treatment agents such as silane coupling agents can be used. As silane coupling agents, alkoxysilane compounds having amino or glycidyl groups as functional groups are well-known and can be appropriately selected. To further improve the interaction with specific polyamic acids, alkoxysilanes containing amino groups are preferred as silane coupling agents. Examples of alkoxysilanes containing amino groups include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 2-aminophenyltrimethoxysilane, and 3-aminophenyltrimethoxysilane. From the viewpoint of raw material stability, 3-aminopropyltriethoxysilane is preferred. One method for surface treatment of nano-silica particles is to stir a mixture obtained by adding a silane coupling agent to a dispersion (organosilicone sol) at an atmosphere temperature of 20°C to 80°C. The stirring time is, for example, 1 hour to 10 hours. A catalyst to promote the reaction may also be added during this process.

[0111] Regarding the nano-silica-polyamic acid composite formed by combining a specific polyamic acid with nano-silica particles, it is preferable that the nano-silica particles are contained in the range of 1 part by weight or more and 30 parts by weight or less relative to 100 parts by weight of the specific polyamic acid, more preferably in the range of 1 part by weight or more and 20 parts by weight or less. If the content of nano-silica particles is 1 part by weight or more, the heat resistance of the polyimide containing nano-silica particles can be improved, and internal stress can be sufficiently reduced. If the content of nano-silica particles is 30 parts by weight or less, adverse effects on the mechanical properties and transparency of the polyimide containing nano-silica particles can be suppressed.

[0112] In addition, to exhibit proper adhesion to the support, the polyamic acid composition of this embodiment may contain a silane coupling agent. Known silane coupling agents may be used without particular limitation, but from the viewpoint of reactivity with a particular polyamic acid, compounds containing amino groups are particularly preferred.

[0113] The mixing ratio of the silane coupling agent to 100 parts by weight of a specific polyamic acid is preferably 0.01 parts by weight or more and 0.50 parts by weight or less, more preferably 0.01 parts by weight or more and 0.10 parts by weight or less, and even more preferably 0.01 parts by weight or more and 0.05 parts by weight or less. By making the mixing ratio of the silane coupling agent 0.01 parts by weight or more, the peeling inhibition effect on the support can be fully exerted, and by making the mixing ratio of the silane coupling agent 0.50 parts by weight or less, the decrease in molecular weight of the specific polyamic acid can be suppressed, thereby suppressing the embrittlement of the polyimide film.

[0114] The polyimide of this embodiment is an imide of the specific polyamic acid described above. The polyimide of this embodiment can be obtained by known methods, and its manufacturing method is not particularly limited. Hereinafter, an example of a method for obtaining the polyimide of this embodiment by imidizing a specific polyamic acid will be described. Imidization is performed by dehydrating and ring-closing the specific polyamic acid. This dehydration and ring-closing can be performed by an azeotropic method using an azeotropic solvent, a thermal method, or a chemical method. Furthermore, the imidization from the specific polyamic acid to the polyimide can be any ratio of 1% to 100%. That is, a portion of the imidized specific polyamic acid can also be synthesized. Especially when imidization is performed by heating, there is a possibility that the ring-closing reaction from a specific polyamic acid to a polyimide and the hydrolysis of the specific polyamic acid may occur simultaneously, resulting in a polyimide with a molecular weight lower than that of the specific polyamic acid. Therefore, from the viewpoint of improving mechanical properties, it is preferable to pre-imide a portion of the specific polyamic acid in the polyamic acid composition before forming the polyimide film described below. In this specification, the partially imidized polyamic acid is sometimes also referred to as "polyamic acid".

[0115] The dehydration and ring-closing of a specific polyamic acid can be achieved simply by heating the specific polyamic acid. The method of heating the specific polyamic acid is not particularly limited; for example, after coating the polyamic acid composition of this embodiment onto a support such as a glass substrate, metal plate, or PET film (polyethylene terephthalate film), heat treatment of the specific polyamic acid can be performed at a temperature in the range of 40°C to 500°C. According to this method, a laminate of this embodiment having a support and a polyimide film (specifically, a polyimide film containing an imide compound of the specific polyamic acid) disposed on the support is obtained. Alternatively, the dehydration and ring-closing of the specific polyamic acid can be achieved by directly placing the polyamic acid composition into a container that has undergone a molding process such as coating with a fluorinated resin, and heating / drying the polyamic acid composition under reduced pressure. By using these methods to achieve the dehydration and ring-closing of the specific polyamic acid, polyimides can be obtained. It should be noted that the heating time for each of the above treatments varies depending on the amount of polyamic acid composition to be dehydrated and closed-loop and the heating temperature. However, in general, it is preferred to set the heating time to be between 1 minute and 300 minutes after the treatment temperature reaches the maximum temperature.

[0116] The polyimide film of this embodiment (more specifically, a polyimide film containing an imide compound of a specific polyamic acid) is colorless, transparent, and has low yellowness, and possesses a glass transition temperature (heat resistance) capable of withstanding TFT fabrication steps, thus making it suitable as a transparent substrate material for flexible displays. The content of polyimide (more specifically, an imide compound of a specific polyamic acid) in the polyimide film of this embodiment is, for example, 70% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more, and may also be 100% by weight, relative to the total amount of the polyimide film. Other components in the polyimide film besides polyimide include, for example, the aforementioned additives (more specifically, microparticles, etc.).

[0117] The electronic device (more specifically, a flexible device, etc.) of this embodiment has the polyimide film of this embodiment and electronic components disposed directly or indirectly on the polyimide film. When manufacturing the electronic device of this embodiment for a flexible display, firstly, an inorganic substrate such as glass is used as a support, and a polyimide film is formed on it. Then, electronic components such as TFTs are disposed (formed) on the polyimide film, thereby forming the electronic device on the support. The TFT formation step is generally performed in a wide temperature range of 150°C to 650°C, but in order to substantially achieve the desired performance, an oxide semiconductor layer or an a-Si (amorphous silicon) layer may be formed at 300°C or higher. Depending on the situation, the a-Si may be further crystallized using a laser or the like.

[0118] At this point, when the thermal decomposition temperature of the polyimide film is low, gas release may occur during the formation of electronic components. This gas release may adhere to the oven in the form of sublimation, causing oven contamination, or the inorganic film (such as the barrier film described below) formed on the polyimide film or the electronic components may peel off. Therefore, the 1% weight loss temperature of the polyimide is preferably 500°C or higher. The higher the upper limit of the 1% weight loss temperature of the polyimide, the better, for example, 600°C. The 1% weight loss temperature can be adjusted, for example, by changing the content of residues with rigid structures (more specifically, s-BPDA residues, etc.). To explain in more detail, before forming the TFT, an inorganic film such as a silicon oxide film (SiOx film) or a silicon nitride film (SiNx film) is formed on the polyimide film as a barrier film. In cases where the heat resistance of the polyimide is low, imidization is incomplete, or there is a high amount of residual solvent, the polyimide may peel off from the inorganic film during high-temperature processes following the lamination of the inorganic film due to volatile components such as decomposition gases. Therefore, ideally, in addition to a 1% weight loss temperature of 500°C or higher for the polyimide, the weight loss rate when isothermally holding the polyimide at temperatures between 400°C and 450°C should not exceed 1%.

[0119] As described above, polyimides manufactured using specific polyamic acids can suppress the generation of hydrogen fluoride during high-temperature processes. As an indicator of the amount of hydrogen fluoride gas generated when using an imide of a specific polyamic acid (the polyimide of this embodiment) in a high-temperature process, the detection intensity ratio obtained from mass spectrometry can be cited as an example. Specifically, firstly, under a helium gas flow, the polyimide is heated from an atmosphere temperature of 60°C to 500°C at a heating rate of 10°C / min, and the gas generated by the polyimide is analyzed using a quadrupole mass spectrometer. Then, in the obtained mass spectrum, the detection intensity of the peak at m / z=20 (presumably caused by hydrogen fluoride) at an atmosphere temperature of 450°C is calculated and divided by the detection intensity of the peak at m / z=20 at an atmosphere temperature of 100°C. Hereinafter, the value obtained by dividing the detection intensity of the peak with m / z=20 at an atmosphere temperature of 450°C by the detection intensity of the peak with m / z=20 at an atmosphere temperature of 100°C is sometimes recorded as the HF intensity ratio. A trend shows that the greater the amount of hydrogen fluoride gas generated in the high-temperature process, the larger the HF intensity ratio. It should be noted that the helium flow rate used for analysis with a quadrupole mass spectrometer can be set in a manner that allows for real-time analysis of the gas generated by the polyimide, for example, in the range of 50 mL / min to 150 mL / min, preferably in the range of 80 mL / min to 120 mL / min.

[0120] To obtain polyimide capable of further suppressing hydrogen fluoride generation during high-temperature processes, the HF strength ratio is preferably 3.0 or less, more preferably 2.5 or less. The lower limit of the HF strength ratio is not particularly limited and may also be 0.

[0121] Furthermore, when the glass transition temperature (Tg) of polyimide is significantly lower than the process temperature, positional shifts may occur during the formation of electronic components. Therefore, the Tg of polyimide is preferably 300°C or higher, more preferably 350°C or higher, and even more preferably 400°C or higher, and even more preferably 420°C or higher. A higher upper limit for the Tg of polyimide is preferable, for example, 470°C. Additionally, generally, the coefficient of thermal expansion of the glass substrate is lower than that of the resin, thus internal stress is generated between the glass substrate and the polyimide film. If the internal stress of the glass substrate used as a support or the laminate containing the electronic component and the polyimide film is high, the laminate containing the polyimide film will expand during the high-temperature TFT formation step and then shrink when cooled to room temperature, resulting in problems such as warping and breakage of the glass substrate, and peeling of the polyimide film from the glass substrate. Therefore, in the laminate having a glass substrate (support) and a polyimide film (the laminate of this embodiment), the internal stress between the polyimide film and the glass substrate is preferably 50 MPa or less, more preferably 45 MPa or less, even more preferably 40 MPa or less, even more preferably 35 MPa or less, and particularly preferably 30 MPa or less. The lower the lower limit of the internal stress, the better. The method for measuring the internal stress is the same as or based on the method described in the following examples.

[0122] The polyimide of this embodiment is suitable for use as a material for display substrates such as TFT substrates and touch panel substrates. When using polyimide for the above-mentioned applications, in most cases, the method described above is used to form electronic devices on a support (more specifically, electronic devices obtained by forming electronic components on a polyimide film), and then peel the polyimide film off from the support. Furthermore, alkali-free glass is suitable as the material for the support. Hereinafter, an example of a method for manufacturing a laminate of polyimide film and support will be described in detail.

[0123] First, the polyamic acid composition of this embodiment is coated (cast) onto a support to form a laminate containing a coated film containing a specific polyamic acid and a support. Next, the laminate containing the coated film is heated at a temperature of, for example, 40°C or higher and 200°C or lower. The heating time is, for example, 3 minutes to 120 minutes. It should be noted that multi-stage heating steps may also be provided, such as heating the laminate containing the coated film at 50°C for 30 minutes, and then heating at 100°C for 30 minutes. Next, in order to promote the imidization of the specific polyamic acid in the coated film, the laminate containing the coated film is heated at a maximum temperature of, for example, 200°C or higher and 500°C or lower. The heating time (heating time at the maximum temperature) is, for example, 1 minute or higher and 300 minutes or lower. It is preferable to gradually increase the temperature from a low temperature to the maximum temperature. The heating rate is preferably 2°C / min to 10°C / min, more preferably 4°C / min to 10°C / min. Furthermore, the maximum temperature is preferably in the range of 250°C to 450°C. If the maximum temperature is 250°C or higher, imidization is sufficient; if the maximum temperature is 450°C or lower, thermal degradation of the polyimide can be suppressed. Alternatively, the temperature can be maintained at any temperature for any time before reaching the maximum temperature. The imidization reaction can be carried out in air, under reduced pressure, or in a non-reactive gas such as nitrogen. To exhibit higher transparency, it is preferable to carry it under reduced pressure or in a non-reactive gas such as nitrogen. As a heating device, known devices such as hot air ovens, infrared ovens, vacuum ovens, non-oxidizing ovens, and heating plates can be used. Through these steps, the specific polyamic acid in the coated film is imidized, and a laminate of the support and the polyimide film (a film containing an imide of the specific polyamic acid) can be obtained (i.e., the laminate of this embodiment).

[0124] The method for peeling the polyimide film from the obtained support and the polyimide film laminate can be a known method. For example, it can be peeled by hand, or by using mechanical devices such as drive rollers or robots. Alternatively, a method can be used to provide a release layer between the support and the polyimide film; or a method can be used to peel the polyimide film by forming a silicon oxide film on a substrate with multiple trenches, using the silicon oxide film as a base layer to form the polyimide film, and then allowing an etching solution of the silicon oxide film to wet between the substrate and the silicon oxide film. Another method can be used to separate the polyimide film by irradiating it with laser light.

[0125] The transparency of the polyimide film can be evaluated using the total transmittance (TT) based on JIS K7361-1:1997 and the haze based on JIS K7136-2000. When the polyimide film is used in applications requiring high transparency, the total transmittance of the polyimide film is preferably 75% or more, more preferably 80% or more. Furthermore, when the polyimide film is used in applications requiring high transparency, the haze of the polyimide film is preferably 1.5% or less, more preferably 1.2% or less, even more preferably 1.0% or less, even more preferably 0.8% or less, and can also be 0%. In applications requiring high transparency, the polyimide film is required to have high transmittance across the entire wavelength range; however, polyimide films tend to absorb light from shorter wavelengths, often resulting in a yellowish tint. To use the polyimide film in applications requiring high transparency, it is preferable to minimize the coloring of the polyimide film. Specifically, for polyimide films to be used in applications requiring high transparency, the yellowness (YI) of the polyimide film is preferably 20 or less, more preferably 15 or less, and may also be 0. YI can be measured according to JIS K7373-2006. Thus, polyimide films that achieve transparency through reduced coloration are suitable for transparent substrates used as glass replacements, and substrates on which sensors or camera modules are mounted on the back.

[0126] Furthermore, in applications requiring transparency, from the viewpoint of color reproduction, a high transmittance of blue light (light with a wavelength around 470 nm) is particularly desirable. From a practical standpoint, a high transmittance of light with a wavelength of 400 nm (400 nm transmittance) is required. From the viewpoint of color reproduction, the 400 nm transmittance of the polyimide film is preferably 30% or more, more preferably 40% or more, further preferably 50% or more, and even more preferably 60% or more. There is no particular upper limit to the 400 nm transmittance of the polyimide film; it can also be 100%.

[0127] Furthermore, in the light extraction methods of flexible displays, there are two types: top-emitting method, which extracts light from the surface side of the TFT, and bottom-emitting method, which extracts light from the back side of the TFT. In the top-emitting method, since the light is not blocked by the TFT, it is easy to increase the aperture ratio and obtain high-resolution image quality. The bottom-emitting method is easy to align the TFT and pixel electrodes, making it easier to manufacture. If the TFT is transparent, the aperture ratio can also be increased in the bottom-emitting method. Therefore, large displays tend to use the bottom-emitting method because it is easier to manufacture. The polyimide film of this embodiment has a low YI and excellent heat resistance, so it can be applied to either of the above-mentioned light extraction methods.

[0128] Furthermore, in batch manufacturing processes where a polyamic acid composition is coated onto a support such as a glass substrate, and then heated to imidize it to form electronic components, followed by peeling off the polyimide film, it is preferable to have excellent adhesion between the support and the polyimide film. Here, adhesion refers to adhesion strength. In manufacturing processes where electronic components are formed on the polyimide film on the support, and the polyimide film with the formed electronic components is peeled off from the support, excellent adhesion between the polyimide film and the support allows for more accurate formation or mounting of the electronic components. From the viewpoint of improving productivity, in manufacturing processes where electronic components are placed on a support with a polyimide film as a separator, the higher the peel strength between the support and the polyimide film, the better. Specifically, the peel strength is preferably 0.05 N / cm or more, and more preferably 0.1 N / cm or more.

[0129] In the manufacturing process described above, the polyimide film self-supporting body is usually peeled off from the polyimide film laminate using laser irradiation. In this case, the polyimide film must absorb the laser light, therefore the cutoff wavelength of the polyimide film must be longer than the wavelength of the laser light used for peeling. Laser peeling often uses a XeCl excimer laser with a wavelength of 308 nm; therefore, the cutoff wavelength of the polyimide film is preferably 312 nm or more, more preferably 330 nm or more. On the other hand, if the cutoff wavelength is too long, the polyimide film tends to turn yellow; therefore, the cutoff wavelength of the polyimide film is preferably 390 nm or less. From the viewpoint of balancing transparency (low yellowing level) and the processability of laser peeling, the cutoff wavelength of the polyimide film is preferably 320 nm or more and 390 nm or less, more preferably 330 nm or more and 390 nm or less. It should be noted that the cutoff wavelength in this specification refers to the wavelength at which the transmittance measured using a UV-Vis spectrophotometer becomes less than 0.1%.

[0130] The polyamic acid composition and polyimide of this embodiment can be directly used in coating and molding processes for manufacturing articles and components, but can also be used as materials for further coating or other treatments on molded articles formed into films. For use in coating and molding processes, the polyamic acid composition or polyimide can be dissolved or dispersed in an organic solvent as needed, and then, as needed, photocurable components, thermocurable components, non-polymerizable adhesive resins, and other components can be formulated to prepare a composition containing a specific polyamic acid or polyimide.

[0131] Various inorganic films, such as metal oxide films or transparent electrodes, can also be formed on the surface of the polyimide film in this embodiment. There are no particular limitations on the methods for forming these inorganic films; examples include sputtering, vacuum evaporation, ion plating, PVD methods, and CVD methods.

[0132] In addition to heat resistance, low thermal expansion, and transparency, the polyimide film of this embodiment also exhibits low internal stress when forming a laminate with a glass substrate, and ensures excellent adhesion to inorganic materials during high-temperature processes. Therefore, it is preferably used in fields and products where these properties can be utilized. For example, the polyimide film of this embodiment is preferably 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, transparent conductive film substrates, and solar cells. Furthermore, it is more preferably used as a replacement material for parts currently using glass. In these applications, the thickness of the polyimide film is, for example, 1 μm or more and 200 μm or less, preferably 5 μm or more and 100 μm or less. The thickness of the polyimide film can be measured using a laser hologram.

[0133] Furthermore, the polyamic acid composition of this embodiment can be readily used in a method for manufacturing a polyimide film, wherein the polyamic acid composition is coated onto a support, heated to imidize, and then the polyimide film is peeled off from the support. Additionally, the polyamic acid composition of this embodiment can be readily used in a batch device manufacturing process, wherein the polyamic acid composition is coated onto a support, heated to imidize, electronic components or the like are formed on the resulting polyimide film, and then the polyimide film with the electronic components or the like is peeled off from the support. Therefore, this embodiment also includes a method for manufacturing an electronic device, which includes the steps of coating a polyamic acid composition onto a support, heating to imidize, and forming electronic components or the like on a polyimide film formed on the support. Furthermore, this method for manufacturing an electronic device may also include the step of peeling the polyimide film with the electronic components or the like from the support.

[0134] [Example]

[0135] The following describes embodiments of the present invention, but the scope of the present invention is not limited to the following embodiments.

[0136] <Methods for Determining Physical Properties>

[0137] First, the method for determining the physical properties of polyimide (polyimide film) will be explained.

[0138] [Yellow Degree (YI)]

[0139] For the polyimide films in each laminate obtained in the following examples and comparative examples, the transmittance of light with wavelengths of 200 nm to 800 nm was measured using a UV-Vis-NIR spectrophotometer (“V-650” manufactured by Nippon Spectrophotometer Co., Ltd.), and the yellowness (YI) of the polyimide film was calculated according to the formula described in JIS K7373-2006.

[0140] [400nm transmittance]

[0141] The transmittance of light at a wavelength of 400 nm (400 nm transmittance) in the polyimide films of each laminate obtained in the following examples and comparative examples was measured using a UV-Vis-NIR spectrophotometer (V-650 manufactured by Nippon Spectrophotometer Co., Ltd.).

[0142] [Haze]

[0143] For the polyimide films peeled from each laminate obtained in the following examples and comparative examples, the haze was measured using an integrating sphere haze meter (HM-150N manufactured by Murakami Color Technology Research Institute Co., Ltd.) according to the method described in JIS K7136-2000. When the haze was 1.0% or less, it was evaluated as having "excellent transparency." On the other hand, when the haze exceeded 1.0%, it was evaluated as having "poor transparency."

[0144] [Internal Stress]

[0145] On a Corning glass substrate (material: alkali-free glass, thickness: 0.7 mm, size: 100 mm × 100 mm) with pre-measured warpage, the polyamic acid compositions prepared in the following examples and comparative examples were coated using a spin coater. After heating in air at 120°C for 30 minutes, the substrate was then heated at 430°C for 30 minutes under a nitrogen atmosphere to obtain a laminate with a 10 μm thick polyimide film on the glass substrate. To eliminate the influence of water absorption by the polyimide film, the laminate was dried at 120°C for 10 minutes, and then the warpage of the laminate under a nitrogen atmosphere at 25°C was measured using a thin film stress measuring device (FLX-2320-S manufactured by KLA-Tencor). Then, based on the warpage of the glass substrate before polyimide film formation and the warpage of the laminate, the internal stress generated between the glass substrate and the polyimide film was calculated using the Stoney formula.

[0146] [Analysis of gases generated by polyimide membranes]

[0147] An analytical apparatus combining a thermogravimetric analyzer (NETZSCH STA449 F5) and a quadrupole mass spectrometer (JMS-Q1500GC) was used to analyze the gas generated by the polyimide membrane during heating. The analytical sequence is explained below.

[0148] First, using octafluoronaphthalene as a standard, the voltage of the quadrupole mass spectrometer was adjusted to achieve a detection intensity of 800,000 for the peak at m / z=69. Then, using the thermogravimetric analyzer described above, the polyimide films obtained in the examples and comparative examples described below (specifically, each polyimide film sampled from each laminate at a mass of 140 mg) were heated from an ambient temperature of 60°C to 500°C at a heating rate of 10°C / min under a helium flow of 100 mL / min. The gas generated by the polyimide during heating was then analyzed using the quadrupole mass spectrometer to obtain a mass spectrum. The HF intensity ratio was calculated based on the obtained mass spectrum. It should be noted that by heating the polyimide film under a helium flow using the analytical apparatus described above, with helium serving as the carrier gas, the gas generated by the polyimide film can be analyzed in real time using the quadrupole mass spectrometer.

[0149] When the HF intensity ratio is 3.0 or less, it is evaluated as "able to suppress the generation of hydrogen fluoride in high-temperature processes". On the other hand, when the HF intensity ratio exceeds 3.0, it is evaluated as "unable to suppress the generation of hydrogen fluoride in high-temperature processes".

[0150] <Fabrication of Polyimide Film>

[0151] The following describes the methods for preparing the polyimide films (laminates) of the examples and comparative examples. It should be noted that the compounds and reagents will be referred to by the following abbreviations. Furthermore, the preparation of the polyamic acid compositions used in preparing the polyimide films was carried out under a nitrogen atmosphere.

[0152] NMP: N-methyl-2-pyrrolidone

[0153] a-BPDA: 2,3,3',4'-Biphenyltetracarboxylic acid dianhydride

[0154] i-BPDA: 2,2',3,3'-Biphenyltetracarboxylic acid dianhydride

[0155] BPAF: 9,9-bis(3,4-dicarboxyphenyl)fluorene dihydride

[0156] SFDA: Spiro[11H-difurano[3,4-b:3',4'-i]xanton-11,9'-[9H]fluorene]-1,3,7,9-tetraone

[0157] s-BPDA: 3,3',4,4'-Biphenyltetracarboxylic acid dianhydride

[0158] NTCDA: 2,3,6,7-Naphthalenetetracarboxylic acid dianhydride

[0159] TFMOB: 2,2'-bis(trifluoromethoxy)benzidine

[0160] TFMB: 2,2'-bis(trifluoromethyl)benzidine

[0161] 2PhI: 2-Phenylidene Imidazole

[0162] PX-200: Resorcinol poly(di-2,6-dimethyl) phosphate manufactured by Daihachi Chemical Industry Co., Ltd.

[0163] TPP: Triphenyl phosphate

[0164] [Example 1]

[0165] 56.7 g of NMP was added as an organic solvent for polymerization to a 300 mL glass separable flask equipped with a stirrer with a stainless steel stirring rod and a nitrogen inlet tube. Then, while stirring the contents of the flask, 4.908 g of TFMOB was added to the flask to dissolve it. Next, 2.459 g of s-BPDA and 2.633 g of SFDA were added to the contents of the flask, and the contents were stirred for 24 hours at 25°C to obtain a polyamic acid composition. The obtained polyamic acid composition was coated onto a glass substrate (manufactured by Corning Incorporated, material: alkali-free glass, thickness: 0.7 mm, size: 100 mm × 100 mm) using a spin coater. After heating in air at 120°C for 30 minutes, it was heated at 430°C for 30 minutes under a nitrogen atmosphere to obtain a laminate with a 10 μm thick polyimide film on the glass substrate (the laminate of Example 1).

[0166] [Examples 2, 4-6, 9, 12 and Comparative Examples 1-5]

[0167] Except for setting the dianhydride used and its ratio, the diamine used and its ratio, and the thickness of the polyimide film as shown in Table 1, laminates of Examples 2, 4-6, 9, 12, and Comparative Examples 1-5 were obtained by the same method as in Example 1. It should be noted that the total amount of dianhydride used in preparing the polyamic acid composition in any of Examples 2, 4-6, 9, 12, and Comparative Examples 1-5 was the same as in Example 1.

[0168] [Examples 3, 7, 8, 10, 11, and 13-18]

[0169] Except that the dianhydride and its addition ratio, and the diamine and its addition ratio are set as shown in Table 1, the additives are added to the contents of the flask according to the amounts shown in Table 1 after stirring the contents of the flask for 24 hours to obtain the polyamic acid composition, and the thickness of the polyimide film is set as shown in Table 1, the laminates of Examples 3, 7, 8, 10, 11, and 13-18 were obtained by the same method as in Example 1. It should be noted that for any of Examples 3, 7, 8, 10, 11, and 13-18, the total amount of dianhydride used in preparing the polyamic acid composition is the same as in Example 1.

[0170] For Examples 1-18 and Comparative Examples 1-5, the dianhydrides used and their proportions, the diamines used and their proportions, the types and amounts of additives, and the thickness of the polyimide film are shown in Table 1. It should be noted that in Table 1, "-" indicates that the component was not used. Furthermore, the values ​​in the "Dianhydrides" column of Table 1 represent the content (in mol%) of each dianhydride relative to the total amount (100 mol%) of the dianhydrides used. The values ​​in the "Diamines" column of Table 1 represent the content (in mol%) of each diamine relative to the total amount (100 mol%) of the dianhydrides used. The values ​​in the "Amount" column of "Additives" in Table 1 represent the amount of the additives used relative to 100 parts by weight of polyamic acid. Additionally, for any of Examples 1-18 and Comparative Examples 1-5, the molar fraction of each residue of polyamic acid in the prepared polyamic acid composition is consistent with the molar fraction of each monomer (corresponding to each residue) used in the synthesis of polyamic acid.

[0171] In addition, for Examples 1-18 and Comparative Examples 1-5, the internal stress, 400nm transmittance, YI, haze, and HF intensity ratio are shown in Table 2. It should be noted that in Table 2, "-" indicates that no measurement was performed.

[0172] [Table 1]

[0173]

[0174] [Table 2]

[0175]

[0176] As shown in Table 1, the polyamic acid in the polyamic acid compositions prepared in Examples 1-18 contains specific diamine residues (TFMOB residues). Additionally, as shown in Table 1, the polyamic acid in the polyamic acid compositions prepared in Examples 1-18 contains specific dianhydride residues.

[0177] As shown in Table 2, the HF intensity ratio was 3.0 or less in Examples 1 to 18. Therefore, the polyimide films obtained in Examples 1 to 18 can suppress the generation of hydrogen fluoride during high-temperature processes. Furthermore, as shown in Table 2, the haze was 1.0% or less in Examples 1 to 18. Therefore, the polyimide films obtained in Examples 1 to 18 exhibit excellent transparency.

[0178] As shown in Table 1, the polyamic acid in the polyamic acid compositions prepared in Comparative Examples 1 and 3-5 does not contain specific diamine residues. Additionally, as shown in Table 1, the polyamic acid in the polyamic acid compositions prepared in Comparative Examples 1, 2, and 5 does not contain specific dianhydride residues.

[0179] As shown in Table 2, the HF intensity ratio exceeded 3.0 in Comparative Examples 1 and 3-5. Therefore, the polyimide films obtained in Comparative Examples 1 and 3-5 failed to suppress the generation of hydrogen fluoride during the high-temperature process. Furthermore, as shown in Table 2, the haze exceeded 1.0% in Comparative Examples 1, 2, and 5. Therefore, the transparency of the polyimide films obtained in Comparative Examples 1, 2, and 5 was poor.

[0180] The above results show that the polyimide obtained from the polyamic acid composition of the present invention not only has excellent transparency, but also can suppress the generation of hydrogen fluoride in high-temperature processes.

Claims

1. A polyamic acid having a tetracarboxylic dianhydride residue and a diamine residue, The diamine residue comprises a divalent organic group represented by the following general formula (1). The tetracarboxylic acid dianhydride residue comprises one or more of the following groups: tetravalent organic groups represented by chemical formula (2), tetravalent organic groups represented by chemical formula (3), tetravalent organic groups represented by chemical formula (4), tetravalent organic groups represented by chemical formula (5), tetravalent organic groups represented by chemical formula (6), tetravalent organic groups represented by chemical formula (7), tetravalent organic groups represented by chemical formula (8), tetravalent organic groups represented by chemical formula (9), and tetravalent organic groups represented by chemical formula (10). In the general formula (1), R 1 and R 2 Each of the following can be independently represented as trifluoromethoxy, pentafluoroethoxy, or heptafluoropropoxy, where 'a' represents an integer greater than or equal to 1 and less than 4, and 'b' represents an integer greater than or equal to 0 and less than 4. When 'a' represents an integer greater than or equal to 2 and less than 4, multiple R... 1 Choose either the same or different, when b represents an integer greater than 2 and less than 4, multiple R 2 Choose either the same or different, where n represents an integer greater than 0 and less than 3.

2. The polyamic acid as described in claim 1, wherein, The tetracarboxylic acid dianhydride residue further comprises one or more of the group consisting of a tetravalent organic group represented by chemical formula (11), a tetravalent organic group represented by chemical formula (12), and a tetravalent organic group represented by chemical formula (13). 。 3. A polyamic acid composition comprising the polyamic acid of claim 1 and an organic solvent.

4. The polyamic acid composition of claim 3, further comprising one or more compounds selected from the group consisting of tertiary amines, phosphorus-containing compounds, and phenolic compounds.

5. The polyamic acid composition of claim 4, wherein, The amount of one or more compounds selected from the group consisting of tertiary amines, phosphorus-containing compounds and phenolic compounds is 0.001 parts by weight or more and 20 parts by weight or less relative to 100 parts by weight of the polyamic acid.

6. A polyimide, which is an imide of the polyamic acid of claim 1.

7. The polyimide of claim 6, wherein, Under a helium gas flow, the polyimide was heated from an atmosphere temperature of 60°C to 500°C at a heating rate of 10°C / min. The mass spectrum obtained by analyzing the gas generated by the polyimide using a quadrupole mass spectrometer showed that the detection intensity of the peak at m / z=20 at an atmosphere temperature of 450°C was divided by the detection intensity of the peak at m / z=20 at an atmosphere temperature of 100°C, resulting in a value of less than 3.

0.

8. A polyimide film comprising the polyimide of claim 6.

9. The polyimide film as described in claim 8 has a transmittance of more than 30% for light with a wavelength of 400 nm.

10. The polyimide film as described in claim 8, wherein the haze is less than 1.0%.

11. The polyimide film as described in claim 8, wherein the yellowness is 15 or less.

12. A laminate having a support and the polyimide film of claim 8.

13. A method for manufacturing a laminate, comprising a support and a polyimide film. By coating the polyamic acid composition of claim 3 onto a support to form a coating film containing the polyamic acid, the polyamic acid is imidized by heating the coating film.

14. An electronic device having the polyimide film of claim 8 and electronic components disposed on the polyimide film.

Images