Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
  • C08L79/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
  • C08L79/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
  • B32B27/281—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42 comprising polyimides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/34—Layered products comprising a layer of synthetic resin comprising polyamides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
  • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
  • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
  • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
  • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
  • C08G73/1067—Wholly aromatic polyimides, i.e. having both tetracarboxylic and diamino moieties aromatically bound
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
  • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
  • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
  • C08G73/1067—Wholly aromatic polyimides, i.e. having both tetracarboxylic and diamino moieties aromatically bound
  • C08G73/1071—Wholly aromatic polyimides containing oxygen in the form of ether bonds in the main chain
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D179/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen, with or without oxygen, or carbon only, not provided for in groups C09D161/00 - C09D177/00
  • C09D179/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
  • C09D179/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/133305—Flexible substrates, e.g. plastics, organic film
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B33/00—Electroluminescent light sources
  • H05B33/02—Details
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K77/00—Constructional details of devices covered by this subclass and not covered by groups H10K10/80, H10K30/80, H10K50/80 or H10K59/80
  • H10K77/10—Substrates, e.g. flexible substrates
  • H10K77/111—Flexible substrates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2379/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen, or carbon only, not provided for in groups C08J2361/00 - C08J2377/00
  • C08J2379/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
  • C08J2379/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors

Definitions

• the present invention relates to a polyimide precursor composition, a polyimide film, a laminate, an electronic device, a method for producing a laminate, a method for producing a polyimide film, and a method for producing an electronic device.
• various electronic elements such as thin-film transistors and transparent electrodes, are formed on the substrate, and high-temperature processes are required to form these electronic elements.
• Polyimide has sufficient heat resistance to be suitable for high-temperature processes, and its coefficient of linear expansion (CTE) is close to that of glass substrates and electronic elements, making it less susceptible to internal stress and suitable for use as a substrate material for flexible displays, etc.
• Aromatic polyimides are generally colored yellow-brown due to intramolecular conjugation and the formation of charge transfer (CT) complexes, but in top-emission organic electroluminescence (EL) displays and the like, light is extracted from the opposite side of the substrate, so the substrate does not require transparency, and conventional aromatic polyimides have been used.
• CT charge transfer
• EL organic electroluminescence
• the substrate is now required to have high optical properties (more specifically, transparency, etc.).
• Patent Documents 1 and 2 In order to reduce the discoloration of polyimide, techniques are known that use aliphatic monomers to suppress the formation of CT complexes (Patent Documents 1 and 2), that use monomers containing fluorine atoms to increase transparency (Patent Document 3), and that introduce a xanthene structure to increase transparency (Patent Document 4).
• Patent Documents 1 and 2 are highly transparent and have a low CTE, but because they have an aliphatic structure, they have a low thermal decomposition temperature, making them difficult to apply to high-temperature processes when forming electronic devices.
• the polyimide described in Patent Document 3 is highly transparent because it contains fluorine atoms, but there is still room for improvement in terms of heat resistance.
• JP 2016-29177 A JP 2012-41530 A JP 2014-70139 A Special Publication No. 2021-521284
• Patent Document 4 makes it possible to obtain polyimide with excellent transparency.
• the polyimide obtained by the method described in Patent Document 4 tends to have a relatively large CTE. Therefore, it is difficult to obtain polyimide that can reduce the CTE while increasing transparency using only the technology described in Patent Document 4.
• the present invention has been achieved in view of the above circumstances, and aims to provide a polyimide that can reduce CTE while increasing transparency, and a polyimide precursor composition as its precursor. It also aims to provide a product or member that requires heat resistance and transparency, which is manufactured using the polyimide and polyimide precursor composition. In particular, it aims to provide a product or member in which the polyimide film of the present invention is formed on the surface of an inorganic material such as glass, metal, metal oxide, or single crystal silicon.
• the present invention includes the following aspects.
• a polyimide precursor composition comprising a polyimide precursor and an organic solvent,
• the polyimide precursor has a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2)
• a polyimide precursor composition comprising: a polyimide precursor having a structural unit represented by the following general formula (2) in a content of 10 mol % or more and less than 80 mol % based on a total amount of structural units in the polyimide precursor:
• X includes one or more selected from the group consisting of a tetravalent organic group represented by the following chemical formula (3) and a tetravalent organic group represented by the following chemical formula (4)
• Y includes one or more selected from the group consisting of a divalent organic group represented by the following chemical formula (5), a divalent organic group represented by the following chemical formula (6), a divalent organic group represented by the following general formula (7), and a divalent organic group represented by the following general formula (8).
• R1 and R2 each independently represent a monovalent organic group having 1 to 12 carbon atoms or a hydrogen atom
• a plurality of R1s may be the same or different
• a plurality of R2s may be the same or different
• m and n each independently represent an integer of 0 to 3.
• X further comprises one or more selected from the group consisting of a tetravalent organic group represented by the following chemical formula (9), a tetravalent organic group represented by the following chemical formula (10), 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).
• a tetravalent organic group represented by the following chemical formula (9) a tetravalent organic group represented by the following chemical formula (10), 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).
• the polyimide precursor composition according to the above [1] or [2].
• the polyimide precursor composition according to any one of [1] to [4], wherein the organic solvent is at least one selected from the group consisting of N-methyl-2-pyrrolidone, 1-butyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, N,N-dimethylpropionamide, N,N-diethylformamide, and 1,3-dimethyl-2-imidazolidinone.
• the organic solvent is at least one selected from the group consisting of N-methyl-2-pyrrolidone, 1-butyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, N,N-dimethylpropionamide, N,N-diethylformamide, and 1,3-dimethyl-2-imidazolidinone.
• X includes one or more selected from the group consisting of a tetravalent organic group represented by the following chemical formula (3) and a tetravalent organic group represented by the following chemical formula (4)
• Y includes one or more selected from the group consisting of a divalent organic group represented by the following chemical formula (5), a divalent organic group represented by the following chemical formula (6), a divalent organic group represented by the following general formula (7), and a divalent organic group represented by the following general formula (8).
• R1 and R2 each independently represent a monovalent organic group having 1 to 12 carbon atoms or a hydrogen atom
• a plurality of R1s may be the same or different
• a plurality of R2s may be the same or different
• m and n each independently represent an integer of 0 to 3.
• a content of one or more residues selected from the group consisting of a divalent organic group represented by the chemical formula (5), a divalent organic group represented by the chemical formula (6), a divalent organic group represented by the general formula (7), and a divalent organic group represented by the general formula (8) is 50 mol % or more and 100 mol % or less based on the total amount of diamine residues in the polyimide
• X further includes at least one selected from the group consisting of a tetravalent organic group represented by the following chemical formula (9), a tetravalent organic group represented by the following chemical formula (10), 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):
• a method for producing a laminate having a support and a polyimide film comprising the steps of: A step Sa of forming a coating film containing the polyimide precursor by applying the polyimide precursor composition according to any one of the above [1] to [5] onto a support; and a step Sb of heating the coating film obtained in the step Sa to imidize the polyimide precursor, thereby forming a polyimide film on the support.
• a method for producing a polyimide film comprising forming a laminate having a support and a polyimide film by the method described in [12] above, and peeling the polyimide film from the support.
• a method for manufacturing an electronic device comprising forming a laminate having a support and a polyimide film by the method described in [12] above, and forming an electronic element on the polyimide film.
• Polyimides produced using the polyimide precursor composition of the present invention can reduce CTE while increasing transparency. Therefore, polyimides produced using the polyimide precursor composition of the present invention are suitable as materials for electronic devices that require transparency and can reduce internal stress.
• Structural unit refers to a repeating unit that constitutes a polymer.
• Polyamic acid is a polymer that contains a structural unit represented by the following general formula (14) (hereinafter, sometimes referred to as “structural unit (14)”) and has an imidization rate of 0 mol%.
• the method for measuring the "imidization rate” is the same as that described in the examples below or a method equivalent thereto.
• A1 represents a tetracarboxylic dianhydride residue (a tetravalent organic group derived from a tetracarboxylic dianhydride), and A2 represents a diamine residue (a divalent organic group derived from a diamine).
• a “polyimide precursor” is a polymer having a structural unit (14) and a structural unit represented by the following general formula (15) (hereinafter, sometimes referred to as “structural unit (15)”).
• the structural unit (15) is a structural unit in which the amide group in the structural unit (14) is imidized.
• A1 in the general formula (15) is synonymous with A1 in the general formula (14)
• A2 in the general formula (15) is synonymous with A2 in the general formula (14).
• the total content of structural unit (14) and structural unit (15) is preferably 80 mol% or more and 100 mol% or less, more preferably 90 mol% or more and 100 mol% or less, and even more preferably 95 mol% or more and 100 mol% or less, based on the total amount (100 mol%) of structural units in the polyimide precursor, and may be 100 mol%.
• linear expansion coefficient refers to the linear expansion coefficient when cooling from 100°C to 400°C.
• the compound and its derivatives may be collectively referred to by adding "based" after the compound name.
• the compound name is followed by "based" to represent the name of a polymer, it means that the repeating unit of the polymer is derived from the compound or its derivative.
• Tetracarboxylic dianhydride may be referred to as "acid dianhydride”.
• the components and functional groups exemplified in this specification may be used alone or in combination of two or more types.
• the polyimide precursor composition according to the present embodiment includes a polyimide precursor and an organic solvent.
• the polyimide precursor has a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).
• the structural unit represented by general formula (1) may be referred to as "structural unit (1)”.
• the structural unit represented by general formula (2) may be referred to as "structural unit (2)”.
• X includes one or more selected from the group consisting of a tetravalent organic group represented by the following chemical formula (3) and a tetravalent organic group represented by the following chemical formula (4)
• Y includes one or more selected from the group consisting of a divalent organic group represented by the following chemical formula (5), a divalent organic group represented by the following chemical formula (6), a divalent organic group represented by the following general formula (7), and a divalent organic group represented by the following general formula (8).
• R1 and R2 each independently represent a monovalent organic group having 1 to 12 carbon atoms or a hydrogen atom
• a plurality of R1s may be the same or different
• a plurality of R2s may be the same or different
• m and n each independently represent an integer of 0 to 3.
• the content of structural unit (2) is 10 mol % or more and less than 80 mol % relative to the total amount (100 mol %) of structural units in the polyimide precursor.
• the polyimide precursor contained in the polyimide precursor composition according to this embodiment may be referred to as a "specific polyimide precursor.”
• the content of structural unit (2) relative to the total amount (100 mol %) of structural units in the polyimide precursor may be referred to as the "imidization rate.”
• the polyimide produced using the polyimide precursor composition according to this embodiment can reduce the CTE while increasing transparency.
• the reason for this is presumed to be as follows.
• a specific xanthene structure is introduced into the specific polyimide precursor, so when it is made into a polyimide, it has high transparency.
• the xanthene structure having a tetravalent organic group represented by chemical formulas (3) and (4) has a hexafluoroisopropylidene group or a fluorenyl group in the side chain, it is believed that the solubility is improved and gelation can be suppressed when the specific xanthene structure is present in the polymer chain.
• a xanthene structure having a tetravalent organic group represented by chemical formula (3) or (4) is present in the polymer chain, the linearity is increased, and when the polymer chain is partially imidized, the orientation of the polymer chain is drastically induced, and the CTE is reduced. Therefore, the polyimide produced using the polyimide precursor composition according to this embodiment can have a reduced CTE.
• the imidization rate is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 35 mol% or more, even more preferably 36 mol% or more, and may be 37 mol% or more, 38 mol% or more, 39 mol% or more, or 40 mol% or more.
• the imidization rate is preferably 70 mol% or less, more preferably 60 mol% or less, even more preferably 50 mol% or less, and even more preferably 45 mol% or less.
• the tetravalent organic group represented by chemical formula (3) is a partial structure (residue) derived from 9,9-bis(trifluoromethyl)-2,3,6,7-xanthenetetracarboxylic dianhydride (hereinafter, sometimes referred to as "6FCDA").
• the tetravalent organic group represented by chemical formula (4) is a partial structure (residue) derived from spiro[11H-difuro[3,4-b:3',4'-i]xanthene-11,9'-[9H]fluorene]-1,3,7,9-tetrone (hereinafter, sometimes referred to as "SFDA").
• the specific polyimide precursor has one or more tetracarboxylic dianhydride residues selected from the group consisting of 6FCDA residues and SFDA residues.
• the content of one or more residues selected from the group consisting of 6FCDA residues and SFDA residues is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 20 mol% or more, even more preferably 30 mol% or more, and may be 40 mol% or more or 50 mol% or more, relative to the total amount (100 mol%) of tetracarboxylic dianhydride residues in the specific polyimide precursor.
• the content of one or more residues selected from the group consisting of 6FCDA residues and SFDA residues may be 100 mol% based on the total amount (100 mol%) of tetracarboxylic dianhydride residues in the specific polyimide precursor, or the specific polyimide precursor may contain acid dianhydride residues (other acid dianhydride residues) other than 6FCDA residues and SFDA residues.
• the content of one or more residues selected from the group consisting of 6FCDA residues and SFDA residues is preferably 95 mol% or less, more preferably 90 mol% or less, and may be 80 mol% or less or 70 mol% or less based on the total amount of tetracarboxylic dianhydride residues in the specific polyimide precursor.
• the specific polyimide precursor contains an SFDA residue.
• dianhydrides other than 6FCDA and SFDA may be used as monomers as long as their performance is not impaired.
• acid dianhydrides other than 6FCDA and SFDA include 3,3',4,4'-biphenyltetracarboxylic dianhydride (hereinafter sometimes referred to as "BPDA”), 4,4'-oxydiphthalic anhydride (hereinafter sometimes referred to as "ODPA”), 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (hereinafter sometimes referred to as "6FDA”), 2,3,3',4'-biphenyltetracarboxylic dianhydride (hereinafter sometimes referred to as "a-BPDA”), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (hereinafter sometimes referred to as "BPAF”), pyromellitic dianhydride (hereinafter sometimes BPDA”), pyromellitic
• the content of one or more residues selected from the group consisting of BPDA residues, ODPA residues, 6FDA residues, a-BPDA residues, and BPAF residues is preferably 5 mol% to 95 mol%, more preferably 5 mol% to 90 mol%, even more preferably 5 mol% to 80 mol%, even more preferably 5 mol% to 70 mol%, and may be 5 mol% to 60 mol% or 5 mol% to 50 mol%.
• the specific polyimide precursor preferably contains one or more residues selected from the group consisting of BPDA residues, ODPA residues, and 6FDA residues as other acid dianhydride residues.
• the BPDA residue is a tetravalent organic group represented by the following chemical formula (9).
• the ODPA residue is a tetravalent organic group represented by the following chemical formula (10).
• the 6FDA residue is a tetravalent organic group represented by the following chemical formula (11).
• the a-BPDA residue is a tetravalent organic group represented by the following chemical formula (12).
• the BPAF residue is a tetravalent organic group represented by the following chemical formula (13).
• the specific polyimide precursor has, as Y in the structural units (1) and (2), one or more diamine residues selected from the group consisting of a divalent organic group represented by chemical formula (5), a divalent organic group represented by chemical formula (6), a divalent organic group represented by general formula (7), and a divalent organic group represented by general formula (8).
• the specific diamine residues have high linearity and therefore contribute to reducing the CTE.
• the divalent organic group represented by general formula (7) may be referred to as "diamine residue (7)”.
• the divalent organic group represented by general formula (8) may be referred to as "diamine residue (8)".
• the divalent organic group represented by chemical formula (5) is a partial structure (residue) derived from p-phenylenediamine (hereinafter sometimes referred to as "PDA").
• the divalent organic group represented by chemical formula (6) is a partial structure (residue) derived from trans-1,4-cyclohexanediamine (hereinafter sometimes referred to as "CHDA").
• the specific polyimide precursor preferably has one or more diamine residues selected from the group consisting of diamine residues (7) and diamine residues (8), and more preferably has diamine residue (7).
• diamine residue (7) one or more diamine residues selected from the group consisting of diamine residues derived from 4-aminophenyl-4-aminobenzoate (hereinafter sometimes referred to as "4-BAAB”) and diamine residues derived from (2-phenyl-4-aminophenyl)-4-aminobenzoate (hereinafter sometimes referred to as "PHBAAB”) are preferred.
• the specific polyimide precursor in order to further reduce the CTE, preferably has one or more diamine residues selected from the group consisting of 4-BAAB residues and PHBAAB residues. In order to particularly reduce the CTE, the specific polyimide precursor preferably has 4-BAAB residues.
• diamines other than PDA, CHDA, the diamines for forming the diamine residue (7), and the diamines for forming the diamine residue (8) may be used as monomers within the scope of not impairing the performance of the precursor.
• diamines other than PDA, CHDA, the diamines for forming the diamine residue (7), and the diamines for forming the diamine residue (8) include, for example, 9,9-bis(4-aminophenyl)fluorene (hereinafter sometimes referred to as "BAFL”), 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (hereinafter sometimes referred to as "6FODA”), 4,4'-diaminodiphenyl sulfone (hereinafter sometimes referred to as "DDS”), 4,4'-diaminobenzanilide (hereinafter sometimes referred to as "DABA”), 1,3-bis(3-aminopropyl)tetrahydrofuran (hereinafter sometimes referred to as "DDS”), 1,3-bis(3-aminopropyl)tetrahydrofuran (hereinafter sometimes referred to as "DABA ...
• BAFL 9,9
• Examples of such compounds include tetramethyldisiloxane (hereinafter sometimes referred to as "PAM-E"), m-phenylenediamine, 4,4'-oxydianiline, 3,4'-oxydianiline, N,N'-bis(4-aminophenyl)terephthalamide, 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), and derivatives thereof, which may be used alone or in combination.
• PAM-E tetramethyldisiloxane
• m-phenylenediamine 4,4'-oxydianiline, 3,4'-oxydianiline, N,N'-bis(
• BAFL, 6FODA and DDS can improve solubility
• DABA is effective in reducing CTE
• PAM-E can increase adhesion to the substrate.
• the content of one or more residues selected from the group consisting of PDA residues, CHDA residues, diamine residues (7) and diamine residues (8) is preferably 50 mol% or more and 100 mol% or less, more preferably 60 mol% or more and 100 mol% or less, even more preferably 70 mol% or more and 100 mol% or less, even more preferably 80 mol% or more and 100 mol% or less, and particularly preferably 90 mol% or more and 100 mol% or less, relative to the total amount (100 mol%) of diamine residues in the specific polyimide precursor.
• the specific polyimide precursor preferably satisfies the following condition 1, more preferably satisfies the following condition 2, and further preferably satisfies the following condition 3.
• Condition 1 the imidization rate is 20 mol % or more and 60 mol % or less.
• Requirement 2 The above requirement 1 is satisfied and the acid dianhydride residue has an SFDA residue.
• Requirement 3 The above requirement 2 is satisfied and the diamine residue has a 4-BAAB residue.
• the specific polyimide precursor is obtained by partially imidizing a polyamic acid of a specific structure (hereinafter, sometimes referred to as "polyamic acid (1)").
• Polyamic acid (1) can be synthesized by a known general method, for example, by reacting a diamine with a tetracarboxylic dianhydride in an organic solvent.
• An example of a specific synthesis method for polyamic acid (1) will be described. First, in an inert gas atmosphere such as argon or nitrogen, a diamine is dissolved or dispersed in a slurry state in an organic solvent to prepare a diamine solution. Then, the tetracarboxylic dianhydride is added to the diamine solution after being dissolved or dispersed in a slurry state in an organic solvent, or in a solid state.
• the desired polyamic acid (1) (polymer of diamine and tetracarboxylic dianhydride) can be obtained by adjusting the amount of diamine (when multiple diamines are used, the amount of each diamine) and the amount of tetracarboxylic dianhydride (when multiple tetracarboxylic dianhydrides are used, the amount of each tetracarboxylic dianhydride).
• the molar fraction of each residue in polyamic acid (1) is, for example, equal to the molar fraction of each monomer (diamine and tetracarboxylic dianhydride) used in the synthesis of polyamic acid (1).
• polyamic acid (1) containing multiple types of tetracarboxylic dianhydride residues and multiple types of diamine residues can be obtained.
• the temperature conditions of the reaction between diamine and tetracarboxylic dianhydride, i.e., the synthesis reaction of polyamic acid (1) 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 polyamic acid (1) is, for example, in the range of 10 minutes to 30 hours.
• the organic solvent used in the 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 resulting polyamic acid (1).
• organic solvents used in the synthesis of polyamic acid (1) include urea-based solvents such as tetramethylurea and N,N-dimethylethylurea; sulfoxide-based solvents such as dimethylsulfoxide; sulfone-based solvents such as diphenylsulfone and tetramethylsulfone; N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 1-butyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide (MPA), 3-butoxy-N,N-dimethylpropanamide, N,N-dimethylpropionamide, N,N
• suitable solvents include amide solvents such as diethylformamide, 1,3-dimethyl-2-imidazolidinone, and hexamethylphosphoric triamide; ester
• the organic solvent used in the synthesis reaction of polyamic acid (1) 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, and even more preferably one or more solvents selected from the group consisting of NMP, MPA, 1-butyl-2-pyrrolidone, 3-butoxy-N,N-dimethylpropanamide, N,N-dimethylpropionamide, N,N-diethylformamide, and 1,3-dimethyl-2-imidazolidinone.
• the synthesis reaction of polyamic acid (1) is preferably carried out under an inert gas atmosphere such as argon or nitrogen.
• the polyimide precursor composition according to this embodiment includes a specific polyimide precursor and an organic solvent.
• the organic solvent is preferably one of those listed as organic solvents used in the synthesis reaction of polyamic acid (1) above.
• the organic solvent in the polyimide precursor composition according to this embodiment 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, and even more preferably one or more solvents selected from the group consisting of NMP, MPA, 1-butyl-2-pyrrolidone, 3-butoxy-N,N-dimethylpropanamide, N,N-dimethylpropionamide, N,N-diethylformamide, and 1,3-dimethyl-2-imidazolidinone.
• the content of the specific polyimide precursor in the polyimide precursor composition according to this embodiment is not particularly limited, but is, for example, 1% by weight to 80% by weight, preferably 5% by weight to 50% by weight, and more preferably 5% by weight to 30% by weight, based on the total amount of the polyimide precursor composition.
• the polyimide precursor composition according to this embodiment may be prepared (partially imidized) from a solution (polyamic acid solution) containing polyamic acid (1) and an organic solvent.
• the organic solvent contained in the polyamic acid solution include the organic solvents exemplified as organic solvents usable in the synthesis reaction of polyamic acid (1).
• the reaction solution solution after reaction
• the solid polyamic acid (1) obtained by removing the solvent from the reaction solution may be dissolved in an organic solvent to prepare the polyamic acid solution.
• polyamic acid undergoes hydrolysis due to the influence of moisture, etc., and the viscosity changes as the molecular weight decreases, so it is desirable to store the polyamic acid solution at about -20°C.
• the polyimide precursor composition according to this embodiment is less susceptible to hydrolysis because part of the polyamic acid (1) is partially imidized, and can be stored stably even at room temperature. Therefore, the polyimide precursor composition according to this embodiment can reduce storage costs and transportation costs.
• the method of partial imidization of polyamic acid (1) is not particularly limited, and can be carried out using a known method.
• Specific methods of partial imidization include thermal methods, chemical methods, and also a method of obtaining a specific polyimide precursor that is partially imidized using a raw material that has been imidized in advance. From the viewpoint of controlling the imidization rate within the above-mentioned specified range, a method of partial imidization using a chemical method (chemical imidization method) is preferable.
• By-products such as tertiary amines generated by the chemical imidization method may be formed into a film while remaining in the polyimide precursor composition, or the specific polyimide precursor may be reprecipitated in a poor solvent to separate the by-products, and then dissolved again in an organic solvent to obtain a polyimide precursor composition.
• An example of a chemical imidization method is to add one or more selected from the group consisting of an imidization catalyst and a dehydration catalyst to a polyamic acid solution containing polyamic acid (1) to partially imidize polyamic acid (1).
• the temperature conditions for partial imidization of polyamic acid (1) are, for example, within a range of 20°C to 150°C.
• the reaction time for partial imidization of polyamic acid (1) is, for example, within a range of 10 minutes to 30 hours.
• the imidization rate can be adjusted by changing at least one of the amount of the imidization catalyst, the amount of the dehydration catalyst, the temperature conditions for partial imidization, and the reaction time for partial imidization.
• the imidization catalyst is not particularly limited, but a tertiary amine can be used.
• the tertiary amine is preferably a heterocyclic tertiary amine.
• Preferred examples of heterocyclic tertiary amines include pyridine, picoline, lutidine, ethylpyridine, diethylpyridine, isoquinoline, and 1,2-dimethylimidazole.
• the dehydration catalyst is not particularly limited, but preferred examples include acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride.
• the amount of the imidization catalyst added is preferably 0.1 to 1.5 molar equivalents relative to the amide group of polyamic acid (1), more preferably 0.2 to 1.0 molar equivalents, and even more preferably 0.3 to 0.8 molar equivalents.
• the amount of the dehydration catalyst added is preferably 0.1 to 0.9 molar equivalents relative to the amide group of polyamic acid (1), more preferably 0.1 to 0.8 molar equivalents, more preferably 0.2 to 0.7 molar equivalents, and especially preferably 0.3 to 0.6 molar equivalents.
• the imidization catalyst and/or dehydration catalyst When the imidization catalyst and/or dehydration catalyst are added to the polyamic acid solution, they may be added directly without being dissolved in an organic solvent, or the solution may be added after being dissolved in an organic solvent. In the method of adding the catalyst directly without dissolving it in an organic solvent, the reaction may proceed too quickly before the imidization catalyst and/or dehydration catalyst can diffuse, resulting in the formation of a gel. Therefore, it is more preferable to mix a solution obtained by dissolving the imidization catalyst and/or dehydration catalyst in an organic solvent with the polyamic acid solution.
• the pre-imidized raw material is preferably one or more selected from the group consisting of diamines represented by the following general formula (16) and acid dianhydrides represented by the following general formula (17).
• a specific example of the diamine represented by the following general formula (16) is the diamine represented by the following chemical formula (18).
• a specific example of the acid dianhydride represented by the following general formula (17) is the acid dianhydride represented by the following chemical formula (19).
• Such pre-imidized raw material can be synthesized by a thermal imidization method or a chemical imidization method using at least two equivalents of diamine or acid dianhydride relative to the acid dianhydride or diamine. It can also be obtained by reacting an acid dianhydride with a nitro group-containing amine such as nitroaniline, then imidizing it using a thermal imidization method or a chemical imidization method, and then reducing the nitro group.
• each A independently represents a tetravalent organic group
• each B independently represents a divalent organic group
• the weight average molecular weight of the specific polyimide precursor depends on the application, but 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 more, the viscosity of the polyimide precursor composition can be easily adjusted to a range suitable for coating (for example, 0.5 Pa ⁇ s to 10 Pa ⁇ s). On the other hand, if the weight average molecular weight is 1,000,000 or less, sufficient solubility in the solvent is exhibited, so that a coating film or polyimide film having a smooth surface and a uniform thickness can be obtained using the polyimide precursor composition described later.
• the weight average molecular weight used here refers to a polyethylene oxide equivalent value measured using gel permeation chromatography (GPC).
• a method for controlling the molecular weight of the specific polyimide precursor there is a method of using an excess of either the acid dianhydride or the diamine, or a method of quenching the reaction by reacting with a monofunctional acid anhydride or amine such as phthalic anhydride or aniline.
• a monofunctional acid anhydride or amine such as phthalic anhydride or aniline.
• the above feed molar ratio is the ratio of the total amount of diamine used in the synthesis of the specific polyimide precursor to the total amount of acid dianhydride used in the synthesis of the specific polyimide precursor (total amount of diamine/total amount of acid dianhydride).
• total amount of diamine/total amount of acid dianhydride total amount of acid dianhydride.
• the polyimide precursor composition according to this embodiment may contain various organic or inorganic low molecular weight compounds or polymeric compounds as additives.
• additives that can be used include plasticizers, antioxidants, dyes, surfactants, leveling agents, silicones, fine particles, and sensitizers.
• the fine particles include organic fine particles made of polystyrene, polytetrafluoroethylene, and the like, and inorganic fine particles made of colloidal silica, carbon, layered silicates, and the like, and may have a porous structure or a hollow structure.
• the function and form of the fine particles are not particularly limited, and may be, for example, a pigment, a filler, or a fibrous particle.
• the polyimide precursor composition according to this embodiment may contain a silane coupling agent in order to achieve appropriate adhesion to the support.
• a silane coupling agent Any known silane coupling agent may be used without particular limitation, but compounds containing an amino group are particularly preferred in terms of reactivity with the specific polyimide precursor.
• the blending ratio of the silane coupling agent to 100 parts by weight of the specific polyimide precursor 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.
• the polyimide film according to this embodiment is obtained by imidizing (completely imidizing) the specific polyimide precursor in the polyimide precursor composition according to this embodiment. Therefore, the polyimide film according to this embodiment is a polyimide film containing a polyimide having the structural unit (2).
• the preferred structure of the structural unit (2) (type of each residue, content of each residue, etc.) is the same as the preferred structure of the structural unit (2) of the specific polyimide precursor described above.
• the polyimide film according to this embodiment can be obtained by a known method, and the manufacturing method is not particularly limited. An example of a method for obtaining the polyimide film according to this embodiment by imidizing the specific polyimide precursor will be described below.
• the imidization is performed by dehydrating and ring-closing the specific polyimide precursor.
• This dehydrating and ring-closing can be performed by an azeotropic method using an azeotropic solvent, a thermal method, or a chemical method.
• the dehydration ring closure of the specific polyimide precursor can be performed by heating the specific polyimide precursor.
• the method of heating the specific polyimide precursor can be applied to a support such as a glass substrate, a metal plate, or a PET film (polyethylene terephthalate film), and then the specific polyimide precursor can be heat-treated at a temperature of 40°C to 500°C.
• This method can provide a laminate according to the present embodiment having a support and a polyimide film (more specifically, a polyimide film containing an imidized product of the specific polyimide precursor) disposed on the support.
• the heating time for imidization varies depending on the amount of the specific polyimide precursor to be subjected to dehydration ring closure and the heating temperature, but it is generally preferable to set the heating time to a range of 1 minute to 300 minutes after the treatment temperature reaches the maximum temperature.
• the polyimide film according to this embodiment is obtained using the polyimide precursor composition according to this embodiment, and is therefore a polyimide film with high transparency and low CTE.
• the CTE of the polyimide film according to this embodiment is preferably 30 ppm/K or less, and more preferably 28 ppm/K or less.
• the method for measuring the CTE is the same as that of the examples described below, or a method equivalent thereto.
• the lower limit of the CTE of the polyimide film according to this embodiment is not particularly limited, but is, for example, 10 ppm/K or more.
• the polyimide film according to this embodiment (more specifically, the polyimide film containing the imidized product of the specific polyimide precursor) is colorless and transparent with low yellowness and has a glass transition temperature (heat resistance) that can withstand the manufacturing process of thin film transistors (TFTs), and is therefore suitable as a transparent substrate material for flexible displays.
• the content of polyimide (more specifically, the imidized product of the specific polyimide precursor) in the polyimide film according to 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 be 100% by weight, based on the total amount of the polyimide film.
• components other than polyimide in the polyimide film include the additives described above (more specifically, fine particles, etc.).
• the electronic device according to this embodiment (more specifically, a flexible device, etc.) has the polyimide film according to this embodiment and electronic elements directly or indirectly arranged on the polyimide film.
• the electronic device according to this embodiment may also be an electronic device having a laminate having a support and a polyimide film (more specifically, a polyimide film containing an imidized product of a specific polyimide precursor), and electronic elements directly or indirectly arranged on the polyimide film of this laminate.
• a polyimide film is formed on an inorganic substrate such as glass as a support.
• TFTs electronic elements such as TFTs are arranged (formed) on the polyimide film to form an electronic device on the support.
• the process of forming TFTs is generally carried out in a wide temperature range of 150°C to 650°C, but in order to actually achieve the desired performance, an oxide semiconductor layer or a-Si layer is formed at 300°C or higher, and in some cases, a-Si may be further crystallized by a laser or the like.
• the thermal decomposition temperature of the polyimide film is low, outgassing may occur during the formation of electronic elements, and may adhere to the oven as sublimate, causing contamination inside the oven, or the inorganic film (such as the barrier film described later) and electronic elements formed on the polyimide film may peel off. Therefore, it is preferable that the 1% weight loss temperature of the polyimide is 500°C or higher. The higher the upper limit of the 1% weight loss temperature of the polyimide, the better, but it is, for example, 600°C. The 1% weight loss temperature can be adjusted, for example, by changing the content of residues having a rigid structure (more specifically, BPDA residues, etc.).
• 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.
• SiOx film silicon oxide film
• SiNx film silicon nitride film
• the 1% weight loss temperature of the polyimide is 500°C or higher, and that the weight loss rate when the polyimide is isothermally held at a temperature in the range of 400°C to 450°C is less than 1%.
• the glass transition temperature (Tg) of the polyimide is significantly lower than the process temperature, there is a possibility that misalignment may occur during the formation of electronic elements, so the Tg of the polyimide is preferably 300°C or higher, more preferably 350°C or higher, even more preferably 400°C or higher, and even more preferably 420°C or higher.
• the upper limit of the Tg of the polyimide is, for example, 470°C, although the higher the better.
• CTE coefficient of linear expansion
• the internal stress of the laminate of the glass substrate or electronic element used as the support and the polyimide film is high, the laminate including the polyimide film will expand during the high-temperature TFT formation process and then shrink when cooled to room temperature, causing problems such as warping or breakage of the glass substrate and peeling of the polyimide film from the glass substrate. Therefore, in a laminate having a glass substrate (support) and a polyimide film (a laminate according to this embodiment), the internal stress between the polyimide film and the glass substrate is preferably 40 MPa or less, and more preferably 35 MPa or less. The lower limit of the internal stress is preferably as low as possible, and may be 0 MPa.
• the method for measuring the internal stress is the same as or similar to the method described in the examples below.
• the polyimide according to this embodiment can be suitably used as a material for display substrates such as TFT substrates and touch panel substrates.
• a method is often adopted in which an electronic device (more specifically, an electronic device in which electronic elements are formed on a polyimide film) is formed on a support, and then the polyimide film is peeled off from the support.
• alkali-free glass is suitably used as the material for the support.
• the polyimide precursor composition according to this embodiment is applied (cast) onto a support to form a coating film-containing laminate consisting of a coating film containing a specific polyimide precursor and a support (step Sa).
• the coating film-containing laminate is heated, for example, at a temperature of 40° C. or higher and 200° C. or lower.
• the heating time at this time is, for example, 3 minutes or more and 120 minutes or less.
• a multi-stage heating process may be provided, such as heating the coating film-containing laminate at a temperature of 50° C. for 30 minutes and then at a temperature of 100° C. for 30 minutes.
• the coating film-containing laminate is heated, for example, at a maximum temperature of 200° C. or higher and 500° C. or lower (step Sb).
• the heating time (heating time at the maximum temperature) at this time is, for example, 1 minute or more and 300 minutes or less. At this time, 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, and more preferably 4° C./min to 10° C./min.
• the maximum temperature is preferably in the range of 250°C or more and 450°C or less.
• the imidization reaction can be carried out in air, under reduced pressure, or in an inert gas such as nitrogen, but in order to express higher transparency, it is preferable to carry out the reaction under reduced pressure or in an inert gas such as nitrogen.
• a heating device a known device such as a hot air oven, an infrared oven, a vacuum oven, an inert oven, or a hot plate can be used.
• the specific polyimide precursor in the coating film is imidized, and a laminate (i.e., a laminate according to this embodiment) of the support and the polyimide film (a film containing an imidized product of the specific polyimide precursor) can be obtained.
• the polyimide film can be peeled off from the obtained laminate of the support and the polyimide film by any known method. For example, it may be peeled off by hand, or by using a mechanical device such as a drive roll or a robot. Furthermore, it is also possible to employ a method in which a peeling layer is provided between the support and the polyimide film, or a method in which a silicon oxide film is formed on a substrate having a large number of grooves, a polyimide film is formed using the silicon oxide film as a base layer, and a silicon oxide etching solution is infiltrated between the substrate and the silicon oxide film to peel off the polyimide film. It is also possible to employ a method in which the polyimide film is separated by irradiation with laser light.
• the transparency of a polyimide film can be evaluated by the total light transmittance (TT) according to JIS K7361-1:1997 and the haze according to JIS K7136-2000.
• the total light transmittance of the polyimide film is preferably 75% or more, more preferably 80% or more.
• 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, and may be 0%.
• the polyimide film 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 easily absorb light on the short wavelength side, and the film itself is often colored yellow. In order to use a polyimide film in an application requiring high transparency, it is preferable that the coloring of the polyimide film is reduced. Specifically, in order to use a polyimide film in an application requiring high transparency, the yellowness index (YI) of the polyimide film is preferably 25 or less, more preferably 20 or less, and may be 0. YI can be measured according to JIS K7373-2006. In this way, a polyimide film with reduced coloring and transparency is suitable for transparent substrates such as glass replacement substrates, and substrates on which sensors or camera modules are provided on the back surface.
• YI yellowness index
• the 400 nm transmittance of the polyimide film is preferably 35% or more, more preferably 40% or more, even more preferably 50% or more, and even more preferably 60% or more.
• the upper limit of the 400 nm transmittance of the polyimide film is not particularly limited, and may be 100%.
• the top emission method in which light is extracted from the front side of the TFT
• the bottom emission method in which light is extracted from the back side of the TFT.
• the top emission method is characterized by the fact that the aperture ratio is easily increased because light is not blocked by the TFT, and high-definition image quality can be obtained
• the bottom emission method is characterized by the ease of alignment between the TFT and the pixel electrode, making it easy to manufacture. If the TFT is transparent, it is possible to improve the aperture ratio even in the bottom emission method, so there is a tendency for the bottom emission method, which is easy to manufacture, to be adopted for large displays.
• the polyimide film according to this embodiment has a low YI and excellent heat resistance, so it can be applied to either of the above light extraction methods.
• adhesion means adhesion strength.
• the adhesion between the polyimide film and the support is excellent, electronic elements, etc. can be formed or mounted more accurately. In a production process in which electronic elements, etc.
• the peel strength is preferably 0.05 N/cm or more, and more preferably 0.1 N/cm or more.
• the polyimide film when peeling off the polyimide film from the laminate of the support and the polyimide film, the polyimide film is often peeled off from the support by laser irradiation.
• the cutoff wavelength of the polyimide film is required to be longer than the wavelength of the laser light used for peeling. Since a XeCl excimer laser with a wavelength of 308 nm is often used for laser peeling, the cutoff wavelength of the polyimide film is preferably 312 nm or more, and more preferably 330 nm or more.
• the cutoff wavelength of the polyimide film is preferably 390 nm or less.
• 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.
• the cutoff wavelength refers to the wavelength at which the transmittance is 0.1% or less, as measured by an ultraviolet-visible spectrophotometer.
• the polyimide precursor composition according to this embodiment may be used as is in a coating or molding process for producing a product or component, but may also be used as a material for further coating or other treatment of a molded product formed into a film.
• the polyimide precursor composition may be dissolved or dispersed in an organic solvent as necessary, and further, a photocurable component, a thermosetting component, a non-polymerizable binder resin, and other components may be blended as necessary to prepare a composition containing a specific polyimide precursor.
• inorganic thin films such as metal oxide thin films and transparent electrodes, may be formed on the surface of the polyimide film according to this embodiment.
• the method for forming these inorganic thin films is not particularly limited, and examples include PVD methods such as sputtering, vacuum deposition, and ion plating, and CVD methods.
• the polyimide film according to the present embodiment is preferably used in fields and products where these properties are effective, since it has heat resistance, low thermal expansion, transparency, and the internal stress generated when it is laminated with a glass substrate is small, and it can ensure adhesion with inorganic materials during high-temperature processes.
• the polyimide film according to the present embodiment is preferably used in image display devices such as liquid crystal displays, organic electroluminescence (EL), and electronic paper, printed matter, color filters, flexible displays, optical films, 3D displays, touch panels, transparent conductive film substrates, solar cells, and more preferably as a replacement material for parts where glass is currently used.
• the thickness of the polyimide film is, for example, 1 ⁇ m or more and 200 ⁇ m or less, and preferably 5 ⁇ m or more and 100 ⁇ m or less.
• the thickness of the polyimide film can be measured using a laser hologram.
• the polyimide precursor composition according to this embodiment can be suitably used in a method for producing a polyimide film, in which the polyimide precursor composition is applied to a support, heated to be imidized, and the polyimide film is peeled off from the support.
• the polyimide precursor composition according to this embodiment can be suitably used in a batch-type device production process, in which the polyimide precursor composition is applied to a support, heated to be imidized, electronic elements, etc. are formed on the formed polyimide film, and the polyimide film on which the electronic elements, etc. are formed is peeled off from the support.
• this embodiment also includes a method for producing a polyimide film, in which a laminate is obtained by the above-mentioned method for producing a laminate according to this embodiment, and then the polyimide film is peeled off from the support to obtain a polyimide film.
• This embodiment also includes a method for producing an electronic device, in which an electronic element is formed on the formed polyimide film after a laminate is obtained by the above-mentioned method for producing a laminate according to this embodiment.
• haze was measured using an integrating sphere haze meter ("HM-150N” manufactured by Murakami Color Research Laboratory) 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 "not excellent transparency”.
• Each polyimide precursor composition prepared in the Examples described later or each polyamic acid solution prepared in the Comparative Examples described later was applied by a spin coater onto a Corning glass substrate (material: alkali-free glass, thickness: 0.7 mm, size: 100 mm x 100 mm) whose warpage had been measured in advance, and the substrate was heated in air at 120°C for 30 minutes, and then heated in a nitrogen atmosphere at 430°C for 30 minutes to obtain a laminate having a polyimide film having a thickness of 10 ⁇ m on the glass substrate.
• the laminate was dried at 120°C for 10 minutes, and then the warpage 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" manufactured by KLA Tencor Corporation). Then, the internal stress generated between the glass substrate and the polyimide film was calculated by the Stoney formula from the warpage of the glass substrate before the polyimide film was formed and the warpage of the laminate.
• the internal stress reduction rate is preferably 20% or more, more preferably 50% or more, and even more preferably 80% or more.
• CTE Coefficient of Linear Expansion
• each polyimide precursor composition prepared in the Examples described later or each polyamic acid solution prepared in the Comparative Examples described later was applied onto a glass substrate, and heated in air at 120° C. for 30 minutes, and then heated in a nitrogen atmosphere at 430° C. for 30 minutes to obtain a polyimide film (thickness: 10 ⁇ m).
• each of the obtained polyimide films was measured by total reflection measurement method (ATR method) using a Fourier transform infrared spectrophotometer ("FT/IR-6100" manufactured by JASCO Corporation) to obtain an infrared absorption spectrum.
• FT/IR-6100 Fourier transform infrared spectrophotometer
• each polyimide precursor composition prepared in the Examples described later or each polyamic acid solution prepared in the Comparative Examples described later was applied onto a glass substrate and heated in air at 60° C. for 60 minutes to obtain a film (thickness: 10 ⁇ m).
• each obtained film was measured by total reflection measurement method (ATR method) using a Fourier transform infrared spectrophotometer ("FT/IR-6100" manufactured by JASCO Corporation) to obtain an infrared absorption spectrum.
• FT/IR-6100 Fourier transform infrared spectrophotometer
• IR V the infrared absorption spectrum obtained here
• the imidization ratio (unit: mol%) was calculated from the following formula.
• Imidization rate 100 ⁇ (V 1340 /V 1500 )/(F 1340 /F 1500 )
• V 1500 Peak intensity of aromatic rings near 1500 cm ⁇ 1 of IR
• V 1340 Peak intensity of imide groups near 1340 cm ⁇ 1 of IR
• V F 1500 Peak intensity of aromatic rings near 1500 cm ⁇ 1 of IR F
• F 1340 Peak intensity of imide groups near 1340 cm ⁇ 1 of IR F
• NMP N-methyl-2-pyrrolidone BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride
• SFDA spiro[11H-difuro[3,4-b:3',4'-i]xanthene-11,9'-[9H]fluorene]-1,3,7,9-tetrone
• ODPA 4,4'-oxydiphthalic anhydride
• 4-BAAB 4-aminophenyl-4-aminobenzoate
• DDS 4,4'-diaminodiphenyl sulfone
• Compound 1 Diamine represented by chemical formula (18)
• PDA p-phenylenediamine
• DMI 1,2-dimethylimidazole
• AC 2 O Acetic anhydride
• Polyamic acid solutions P2 to P6 were each prepared by the same method as that for preparing polyamic acid solution P1, except that the acid dianhydrides used and their charging ratios, and the diamines used and their charging ratios were as shown in Table 1.
• the total substance amount of the acid dianhydrides used in preparing the polyamic acid solution was the same as that for polyamic acid solution P1.
• the total substance amount of the diamines used in preparing the polyamic acid solution was the same as that for polyamic acid solution P1.
• Table 1 shows the acid dianhydrides used and their charge ratios, as well as the diamines used and their charge ratios for polyamic acid solutions P1 to P6.
• "-" means that the corresponding component was not used.
• the values in the "acid dianhydride” column are the content (unit: mol%) of each acid dianhydride relative to the total amount of acid dianhydrides used.
• the values in the "diamine” column are the content (unit: mol%) of each diamine relative to the total amount of diamines used.
• Example 1 75.0 g of the polyamic acid solution P1 was placed in a 300 mL glass separable flask equipped with a stirrer equipped with a stainless steel stirring rod and a nitrogen inlet tube. Next, 75.0 g of NMP and 2.56 g of DMI were placed in the flask while stirring the contents of the flask, and the contents of the flask were stirred until they became uniform. Next, 2.72 g of AC 2 O was placed in the flask while stirring the contents of the flask, and the contents of the flask were stirred for 6 hours under an atmosphere at a temperature of 23° C. to obtain a polyimide precursor composition.
• the obtained polyimide precursor composition was applied to a glass substrate (manufactured by Corning, material: alkali-free glass, thickness: 0.7 mm, size: 100 mm x 100 mm) using a spin coater, heated in air at 80° C. for 30 minutes, and then heated in a nitrogen atmosphere at 430° C. for 30 minutes to obtain a laminate (laminate of Example 1) having a polyimide film having a thickness of 10 ⁇ m on the glass substrate.
• Examples 2 to 5 The laminates of Examples 2 to 5 were obtained in the same manner as in Example 1, except that the type of polyamic acid solution used, and the amount of DMI used (added amount) and the amount of AC 2 O used (added amount) were as shown in Table 2.
• Example 6 A 300 mL glass separable flask equipped with a stirrer equipped with a stainless steel stirring rod and a nitrogen inlet tube was charged with 60.0 g of NMP as an organic solvent for polymerization. Then, while stirring the contents of the flask, 8.702 g of compound 1 was added to the flask and dissolved. Then, 6.298 g of SFDA was added to the contents of the flask, and the contents of the flask were stirred for 24 hours under an atmosphere of 23 ° C. Then, 0.15 g of DMI was added to the contents of the flask to obtain a polyimide precursor composition P7.
• the obtained polyimide precursor composition P7 was applied to a glass substrate (manufactured by Corning, material: alkali-free glass, thickness: 0.7 mm, size: 100 mm x 100 mm) using a spin coater, heated in air at 80 ° C. for 30 minutes, and then heated in a nitrogen atmosphere at 430 ° C. for 30 minutes to obtain a laminate (laminate of Example 6) having a polyimide film having a thickness of 10 ⁇ m on the glass substrate.
• the polyamic acid solution P1 was applied 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, heated in air at 120°C for 30 minutes, and then heated in a nitrogen atmosphere at 430°C for 30 minutes to obtain a laminate (laminate of Comparative Example 1) having a 10 ⁇ m-thick polyimide film on the glass substrate.
• a glass substrate manufactured by Corning Incorporated, material: alkali-free glass, thickness: 0.7 mm, size: 100 mm ⁇ 100 mm
• a spin coater heated in air at 120°C for 30 minutes, and then heated in a nitrogen atmosphere at 430°C for 30 minutes to obtain a laminate (laminate of Comparative Example 1) having a 10 ⁇ m-thick polyimide film on the glass substrate.
• Comparative Examples 2 to 6 The laminates of Comparative Examples 2 to 5 were obtained by the same method as in Comparative Example 1, except that the types of polyamic acid solutions used were as shown in Table 2.
• the laminate of Comparative Example 6 was obtained by the same method as in Comparative Example 1, except that polyamic acid solution P6 was used instead of polyamic acid solution P1, and a solution in which a predetermined amount of DMI was added to polyamic acid solution P6 was applied onto a glass substrate.
• Table 2 shows the type of polyamic acid solution used, the amount of DMI used, the amount of AC 2 O used, the imidization rate, internal stress, internal stress reduction rate, CTE, YI, 400 nm transmittance, and haze for Examples 1 to 6 and Comparative Examples 1 to 6.
• the values in the “DMI” and “AC 2 O” columns are all molar equivalent ratios (unit: times molar equivalents) to the amide group of the polyamic acid.
• “-” in the “DMI” and “AC 2 O” columns means that the component was not used.
• P7 in the "Polyamic Acid Solution” column means polyimide precursor composition P7.
• "-" in the "Internal Stress Reduction Rate” column means that the internal stress reduction rate was not measured.
• the imidization rate of the polyimide precursor in the polyimide precursor composition used in Examples 1 to 6 was 10 mol % or more and less than 80 mol % relative to the total amount of structural units in the polyimide precursor.
• the haze was 1.0% or less.
• the polyimide films obtained in Examples 1 to 6 had excellent transparency.
• the CTE was 30 ppm/K or less.
• the polyimide films obtained in Examples 1 to 6 had a reduced CTE.
• the imidization rate of the polyamic acid in the polyamic acid solutions used in Comparative Examples 1 to 6 was 0 mol % relative to the total amount of structural units in the polyamic acid.
• the CTE exceeded 30 ppm/K.
• the polyimide films obtained in Comparative Examples 1 to 6 did not have a reduced CTE.

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