Release layer forming composition and release layer

Abstract

The present invention provides, for example, a release layer-forming composition comprising a polyamic acid represented by the following formula (1) and an organic solvent. (In the formula, X represents an aromatic group represented by the following formula (2) or (3), Y represents a divalent aromatic group, Z represents an aromatic group represented by the following formula (4) or (5) when X is an aromatic group represented by the following formula (2), and represents an aromatic group represented by the following formula (6) or (7) when X is an aromatic group represented by the following formula (3), and m represents a natural number.)

Description

Technical Field

[0001] The present invention relates to a release layer-forming composition and a release layer. Background Art

[0002] In recent years, electronic devices have been required to be thinner and lighter in addition to being able to be bent, which has led to a demand for lightweight flexible plastic substrates instead of conventional heavy, fragile, and non-bendable glass substrates.

[0003] In particular, for next-generation displays, there is a demand for development of an active matrix full-color TFT display panel using a lightweight flexible plastic substrate (hereinafter referred to as a resin substrate).

[0004] Therefore, various methods for manufacturing electronic devices using resin films as substrates have been studied, and for the next generation of displays, research is being conducted on processes that can convert existing TFT display panel manufacturing equipment. Patent documents 1, 2, and 3 disclose the following method: an amorphous silicon thin film layer is formed on a glass substrate, a plastic substrate is formed on the thin film layer, a laser is irradiated from the glass substrate side to crystallize the amorphous silicon, and the plastic substrate is peeled off from the glass substrate using hydrogen generated by the crystallization.

[0005] Patent Document 4 discloses a method of attaching a release layer (described as a "transferred layer" in Patent Document 4) to a plastic film using the techniques disclosed in Patent Documents 1 to 3 to complete a liquid crystal display device.

[0006] However, the methods disclosed in Patent Documents 1 to 4, especially the method disclosed in Patent Document 4, have the following problems: in order to allow the laser to pass through, a highly light-transmitting substrate must be used; laser irradiation with relatively large energy sufficient to allow the laser to pass through the substrate and thereby release hydrogen contained in the amorphous silicon is required; and the laser irradiation sometimes causes damage to the peeled layer.

[0007] Furthermore, when the layer to be peeled off has a large area, laser processing requires a long time, and thus it is difficult to improve the productivity of device production.

[0008] As a means to solve such problems, the following manufacturing process is adopted in Patent Document 5: an existing glass substrate is used as a substrate (hereinafter referred to as a glass substrate), a stripping layer is formed on the glass substrate using a polymer such as a cyclic olefin copolymer, a heat-resistant resin film such as a polyimide film is formed on the stripping layer, an ITO transparent electrode, TFT, etc. are formed and sealed on the film using a vacuum process, and finally the glass substrate is stripped and removed.

[0009] In addition, low-temperature polysilicon TFTs are currently used as TFTs, which have a mobility twice as fast as that of amorphous silicon TFTs. The low-temperature polysilicon TFTs require dehydrogenation annealing at 400°C or above after amorphous silicon is evaporated, and pulsed laser irradiation is performed to crystallize the silicon (hereinafter referred to as TFT processes), and the temperature of the dehydrogenation annealing process is above the glass transition temperature (hereinafter referred to as Tg) of the existing polymer.

[0010] However, it is known that when conventional polymers are heated to a temperature higher than Tg, adhesion is improved (see, for example, Patent Document 6), and adhesion between the peeling layer and the resin substrate is improved after the heat treatment, which may make it difficult to peel the resin substrate from the base.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent Application Laid-Open No. 10-125929

[0014] Patent Document 2: Japanese Patent Application Laid-Open No. 10-125931

[0015] Patent Document 3: International Publication No. 2005 / 050754

[0016] Patent Document 4: Japanese Patent Application Laid-Open No. 10-125930

[0017] Patent Document 5: Japanese Patent Application Publication No. 2010-111853

[0018] Patent Document 6: Japanese Patent Application Publication No. 2008-188792 Summary of the invention

[0019] Problems to be solved by the invention

[0020] The present invention has been made in view of the above-mentioned actual situation, and an object of the present invention is to provide a peeling layer forming composition which can provide a peeling layer that can be peeled without damaging the resin substrate of a flexible electronic device formed thereon and whose peeling properties do not change even after heat treatment at a relatively high temperature such as the above-mentioned TFT process.

[0021] Means for solving problems

[0022] The present inventors have conducted repeated and earnest studies to solve the above-mentioned problems, and as a result, have found that a composition comprising a polyamic acid having specific aromatic groups at both ends of the molecular chain and an organic solvent not only provides a peeling layer having excellent adhesion to a substrate such as a glass substrate and moderate adhesion and moderate peeling properties to a resin substrate used in a flexible electronic device, but also that the moderate adhesion and moderate peeling properties of the peeling layer do not change after the heat treatment in the TFT process and are well maintained, thereby completing the present invention.

[0023] Therefore, the present invention provides the following release layer-forming composition and release layer.

[0024] [1] A release layer forming composition comprising a polyamic acid represented by the following formula (1) and an organic solvent.

[0025] [Chemistry 1]

[0026]

[0027] (In the formula, X represents an aromatic group represented by the following formula (2) or (3), Y represents a divalent aromatic group, Z represents an aromatic group represented by the following formula (4) or (5) when X is an aromatic group represented by the following formula (2), and represents an aromatic group represented by the following formula (6) or (7) when X is an aromatic group represented by the following formula (3), and m represents a natural number.)

[0028] [Chemistry 2]

[0029]

[0030] [Chemistry 3]

[0031]

[0032] [2] The release layer forming composition described in [1], wherein X is an aromatic group represented by the following formulas (8) to (11), and Z is independently an aromatic group represented by the following formula (12) or (13) when X is an aromatic group represented by the following formula (8) or (9), and is independently an aromatic group represented by the following formula (14) or (15) when X is an aromatic group represented by the following formula (10) or (11).

[0033] [Chemistry 4]

[0034]

[0035] [Chemistry 5]

[0036]

[0037] [3] The release layer forming composition according to [1] or [2], wherein Y is a divalent aromatic group containing 1 to 5 benzene rings.

[0038] [4] The release layer forming composition according to [3], wherein Y is at least one selected from the following formulae (16) to (18).

[0039] [Chemistry 6]

[0040]

[0041] (Where R 1 ~R 24 Each of them independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, or an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms which may be substituted by a halogen atom.

[0042] [5] The release layer forming composition according to [4], wherein the R 1 ~R 24 For hydrogen.

[0043] [6] The release layer forming composition according to any one of [1] to [5], wherein m is a natural number of 100 or less.

[0044] [7] The release layer forming composition according to any one of [1] to [6], wherein the organic solvent contains at least one selected from the group consisting of amides represented by formula (S1), amides represented by formula (S2), and amides represented by formula (S3).

[0045] [Chemistry 7]

[0046]

[0047] (Where R 25 and R 26 are independently an alkyl group having 1 to 10 carbon atoms, R 27 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and b represents a natural number. )

[0048] [8] A release layer formed using the release layer forming composition according to any one of [1] to [7].

[0049] [9] A method for producing a flexible electronic device having a resin substrate, characterized by using the release layer described in [8].

[0050]

[10] The manufacturing method described in [9], wherein the resin substrate is a substrate containing polyimide.

[0051] Effects of the Invention

[0052] By using the peeling layer forming composition of the present invention, a peeling layer having excellent adhesion to the substrate and appropriate adhesion to the resin substrate and appropriate peeling properties can be obtained with good reproducibility. In particular, the above-mentioned adhesion and peeling properties are well maintained even after the heat treatment in the TFT process, so that the resin substrate formed on the substrate and the circuits and the like provided thereon are not damaged in the manufacturing process of the flexible electronic device, and it becomes possible to separate the resin substrate from the substrate together with the circuits and the like. Therefore, the peeling layer forming composition of the present invention can contribute to the simplification of the manufacturing process of the flexible electronic device having a resin substrate, the improvement of its yield, etc. DETAILED DESCRIPTION

[0053] The present invention is described in more detail below.

[0054] The release layer forming composition of the present invention contains a polyamic acid represented by the following formula (1) and an organic solvent.

[0055] [Chemistry 8]

[0056]

[0057] In the above formula (1), X represents an aromatic group represented by the following formula (2) or (3), Y represents a divalent aromatic group, Z represents an aromatic group represented by the following formula (4) or (5) when X is an aromatic group represented by the following formula (2), and represents an aromatic group represented by the following formula (6) or (7) when X is an aromatic group represented by the following formula (3), and m represents a natural number.

[0058] [Chemistry 9]

[0059]

[0060] [Chemistry 10]

[0061]

[0062] In the present invention, the peeling layer is a layer provided just above the base (glass base, etc.) on which the resin substrate is to be formed. A typical example thereof is provided in the manufacturing process of a flexible electronic device in order to fix the resin substrate in a predetermined process between the base and the resin substrate of the flexible electronic device made of a resin such as polyimide, and provided in order to make the resin substrate easily peelable from the base after an electronic circuit is formed on the resin substrate.

[0063] The polyamic acid represented by the above formula (1) is obtained by reacting a predetermined tetracarboxylic dianhydride component and a diamine component.

[0064] As the above-mentioned tetracarboxylic dianhydride component, benzene tetracarboxylic dianhydride and biphenyl tetracarboxylic dianhydride can be used. As the above-mentioned diamine component, aliphatic chain, alicyclic, aromatic, aromatic alicyclic can be used. In the present invention, from the viewpoint of improving the function of the obtained film as a peeling layer, it is preferred to react the above-mentioned tetracarboxylic dianhydride with a diamine component containing an aromatic diamine to obtain a polyamic acid, and more preferably to react the above-mentioned tetracarboxylic dianhydride with an aromatic diamine to obtain a fully aromatic polyamic acid.

[0065] The above-mentioned X is preferably an aromatic group represented by the following formulas (8) to (11).

[0066] [Chemistry 11]

[0067]

[0068] In addition, when X is an aromatic group represented by the above formula (8) or formula (9), the above Z is preferably an aromatic group represented by the following formula (12) or formula (13) independently of each other, and when X is an aromatic group represented by the above formula (10) or formula (11), the above Z is preferably an aromatic group represented by the following formula (14) or formula (15) independently of each other.

[0069] [Chemistry 12]

[0070]

[0071] The above Y is preferably an aromatic group containing 1 to 5 benzene rings, and more preferably an aromatic group represented by at least one selected from the following formulae (16) to (18).

[0072] [Chemistry 13]

[0073]

[0074] In the above formulas (16) to (18), R 1 ~R 24 Each of them independently represents a hydrogen atom, a hydroxyl group, a halogen atom, a nitro group, a cyano group, or an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with a halogen atom.

[0075] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0076] Specific examples of the alkyl group having 1 to 20 carbon atoms include any of a linear, branched, and cyclic alkyl group, and include methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl-n-butyl, 1,1-dimethyl-n-propyl, 1,2-dimethyl-n-propyl, 2,2-dimethyl-n-propyl, 1-ethyl-n-propyl, cyclopentyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-propyl, 2,2-dimethyl-n-propyl, 1-ethyl-n-propyl, cyclopentyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1-ethyl-n-butyl, 1-ethyl-n-butyl, 2-ethyl-n-butyl, 1,1,2-trimethyl-n-propyl, 1,2,2-trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl, 1-ethyl-2-methyl-n-propyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, etc.

[0077] Specific examples of the alkenyl group having 2 to 20 carbon atoms include ethenyl, n-1-propenyl, n-2-propenyl, 1-methylethenyl, n-1-butenyl, n-2-butenyl, n-3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylethenyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, n-1-pentenyl, n-1-decenyl, and n-1-eicosenyl.

[0078] Specific examples of the alkynyl group having 2 to 20 carbon atoms include ethynyl, n-1-propynyl, n-2-propynyl, n-1-butynyl, n-2-butynyl, n-3-butynyl, 1-methyl-2-propynyl, n-1-pentynyl, n-2-pentynyl, n-3-pentynyl, n-4-pentynyl, 1-methyl-n-butynyl, 2-methyl-n-butynyl, 3-methyl-n-butynyl, 1,1-dimethyl-n-propynyl, n-1-hexynyl, n-1-decynyl, n-1-pentadecenyl, and n-1-eicosynyl.

[0079] Specific examples of the aryl group having 6 to 20 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthrenyl, 2-phenanthrenyl, 3-phenanthrenyl, 4-phenanthrenyl, and 9-phenanthrenyl.

[0080] Specific examples of the heteroaryl group having 2 to 20 carbon atoms include oxygen-containing heteroaryl groups such as 2-thienyl, 3-thienyl, 2-furyl, 3-furyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 3-isoxazolyl, 4-isoxazolyl, and 5-isoxazolyl; sulfur-containing heteroaryl groups such as 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 3-isothiazolyl, 4-isothiazolyl, and 5-isothiazolyl; 2-imidazoles; 4-Imidazolyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrazinyl, 3-pyrazinyl, 5-pyrazinyl, 6-pyrazinyl, 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, 6-pyrimidinyl, 3-pyridazinyl, 4-pyridazinyl, 5-pyridazinyl, 6-pyridazinyl, 1,2,3-triazin-4-yl, 1,2,3-triazin-5-yl, 1,2, 4-triazine-3-yl, 1,2,4-triazine-5-yl, 1,2,4-triazine-6-yl, 1,3,5-triazine-2-yl, 1,2,4,5-tetrazine-3-yl, 1,2,3,4-tetrazine-5-yl, 2-quinolyl, 3-quinolyl, 4-quinolyl, 5-quinolyl, 6-quinolyl, 7-quinolyl, 8-quinolyl, 1-isoquinolyl, 3-isoquinolyl, 4-isoquinolyl, 5-isoquinolyl, 6-isoquinolyl, 7-isoquinolyl, 8-isoquinolyl, 2-quinoxalinyl, 5-quinoxalinyl, 6-quinoxalinyl, 2-quinazolinyl, 4-quinazolinyl, 5-quinazolinyl, 6-quinazolinyl, 7-quinazolinyl, 8-quinazolinyl, 3-cinnolinyl, 4-cinnolinyl, 5-cinnolinyl, 6-cinnolinyl, 7-cinnolinyl, 8-cinnolinyl and the like nitrogen-containing heteroaryl groups.

[0081] Among these, R 1 ~R 24 Preferred are a hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 20 carbon atoms which may be substituted by a halogen atom, an aryl group having 6 to 20 carbon atoms which may be substituted by a halogen atom, and a heteroaryl group having 2 to 20 carbon atoms which may be substituted by a halogen atom; more preferred are a hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 10 carbon atoms which may be substituted by a halogen atom, and a phenyl group which may be substituted by a halogen atom; further preferred are a hydrogen atom, a fluorine atom, a methyl group, and a trifluoromethyl group; and most preferred is a hydrogen atom.

[0082] The above m may be a natural number, and is preferably a natural number of 100 or less, and more preferably a natural number of 2 to 100.

[0083] Hereinafter, the tetracarboxylic dianhydride component, the diamine component, and the aromatic carboxylic acid component which can be used for the synthesis|combination of the polyamic acid which has the structure represented by said formula (1) are demonstrated in detail.

[0084] As the tetracarboxylic dianhydride component, benzenetetracarboxylic dianhydride and biphenyltetracarboxylic dianhydride can be used.

[0085] Specific examples thereof include pyromellitic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, biphenyl-2,2',3,3'-tetracarboxylic dianhydride, biphenyl-2,3,3',4'-tetracarboxylic dianhydride, biphenyl-3,3',4,4'-tetracarboxylic dianhydride, etc. These can be used alone or in combination of two or more. In the present invention, from the viewpoint of improving the function of the obtained film as a peeling layer, pyromellitic dianhydride and biphenyl-3,3',4,4'-tetracarboxylic dianhydride can be preferably used.

[0086] On the other hand, the aromatic diamine is not particularly limited as long as it has two amino groups directly bonded to an aromatic ring in the molecule, but an aromatic diamine containing 1 to 5 benzene rings is preferred.

[0087] Specific examples of the aromatic diamine having the above structure include 1,4-diaminobenzene (p-phenylenediamine), 1,3-diaminobenzene (m-phenylenediamine), 1,2-diaminobenzene (o-phenylenediamine), 2,4-diaminotoluene, 2,5-diaminotoluene, 2,6-diaminotoluene, 4,6-dimethyl-m-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, 2,6-dimethyl-p-phenylenediamine, 2,4,6-trimethyl-1,3-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 5-(4-(6-nitrophenylenediamine)-1,4-diaminobenzene (o-phenylenediamine), 2,4-diaminotoluene, 2,5-diaminotoluene, 2,6-diaminotoluene, 4,6-dimethyl-m-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, 2,6-dimethyl-p-phenylenediamine, 2,4,6-trimethyl-1,3-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, -trifluoromethylbenzene-1,3-diamine, 5-trifluoromethylbenzene-1,2-diamine, 3,5-bis(trifluoromethyl)benzene-1,2-diamine and other diamines with one benzene ring; 1,2-naphthalenediamine, 1,3-naphthalenediamine, 1,4-naphthalenediamine, 1,5-naphthalenediamine, 1,6-naphthalenediamine, 1,7-naphthalenediamine, 1,8-naphthalenediamine, 2,3-naphthalenediamine, 2,6-naphthalenediamine, 4,4'-biphenylenediamine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'- Dicarboxy-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 4,4'-diamino-N-benzanilide, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)-1,1,1, Diamines having two benzene rings, such as 3,3,3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-bis(trifluoromethyl)biphenyl-4,4'-diamine, 3,3',5,5'-tetrafluorobiphenyl-4,4'-diamine, 4,4'-diaminooctafluorobiphenyl, 2-(3-aminophenyl)-5-aminobenzimidazole, and 2-(4-aminophenyl)-5-aminobenzoxazole;1,5-diaminoanthracene, 2,6-diaminoanthracene, 9,10-diaminoanthracene, 1,8-diaminophenanthrene, 2,7-diaminophenanthrene, 3,6-diaminophenanthrene, 9,10-diaminophenanthrene, 1,3-bis(3-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(3-aminophenyl)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(3-aminophenyl sulfide)benzene, 1,3-bis(4-aminophenyl sulfide)benzene, 1,4-bis(4-aminophenyl)benzene 1,3-bis(3-aminophenylsulfone)benzene, 1,3-bis(4-aminophenylsulfone)benzene, 1,4-bis(4-aminophenylsulfone)benzene, 1,3-bis[2-(4-aminophenyl)isopropyl]benzene, 1,4-bis[2-(3-aminophenyl)isopropyl]benzene, 1,4-bis[2-(4-aminophenyl)isopropyl]benzene, 4,4"-diamino-p-terphenyl, 4,4"-diamino-m-terphenyl and the like diamines having three benzene rings, but not limited thereto. These may be used alone or in combination of two or more. ;

[0088] Among them, from the viewpoint of improving the function of the obtained film as a peeling layer, aromatic diamines having no substituents such as methyl groups on the aromatic ring or on the aromatic ring and the heterocyclic ring condensed therewith are preferred. Specifically, p-phenylenediamine, m-phenylenediamine, 2-(3-aminophenyl)-5-aminobenzimidazole, 2-(4-aminophenyl)-5-aminobenzoxazole, 4,4″-diamino-p-terphenyl, etc. are preferred.

[0089] Furthermore, from the viewpoint of improving the flexibility and heat resistance of the obtained release layer, the diamine component of the present invention may contain a diamine other than the aromatic diamine, and a preferred example thereof includes a diamine represented by the formula (S).

[0090] [Chemistry 14]

[0091]

[0092] In formula (S), each L independently represents an alkanediyl group having 1 to 20 carbon atoms, an alkenediyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms, and each R' independently represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms.

[0093] The number of carbon atoms in such alkanediyl groups, alkenediyl groups and alkynediyl groups is preferably 10 or less, more preferably 5 or less.

[0094] Among them, as L, in consideration of the balance between the solubility of the obtained polyamic acid in an organic solvent and the heat resistance of the obtained film, an alkanediyl group is preferred, and -(CH2) n - group (n = 1 to 10), more preferably -(CH2)n - group (n=1 to 5), and further, considering the availability, a trimethylene group is more preferred.

[0095] Specific examples of the alkyl group having 1 to 20 carbon atoms, the alkenyl group having 2 to 20 carbon atoms, and the alkynyl group having 2 to 20 carbon atoms include the same examples as described above.

[0096] Among them, R' is preferably an alkyl group having 1 to 20 carbon atoms, and more preferably a methyl group or an ethyl group, in consideration of the balance between the solubility of the obtained polyamic acid in an organic solvent and the heat resistance of the obtained film.

[0097] Considering the availability, the function of the obtained film as a peeling layer, etc., the diamine represented by formula (S) is most preferably 1,3-bis(3-aminopropyl)tetramethyldisiloxane. It should be noted that the diamine represented by formula (S) can be obtained as a commercial product or can be synthesized by a known method (for example, the method described in International Publication No. 2010 / 108785).

[0098] Furthermore, other diamines may be used in combination with the above-mentioned aromatic diamines as long as they do not adversely affect the obtained release layer.

[0099] Specific examples of other diamines include 1,4-diaminocyclohexane, 1,4-cyclohexanebis(methylamine), 4,4′-diaminodicyclohexylmethane, bis(4-amino-3-methylcyclohexyl)methane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0 2,6 ] decane, 2,5(6)-bis(aminomethyl)bicyclo[2.2.1]heptane, 1,3-diaminoadamantane, 3,3'-diamino-1,1'-diadamantane, 1,6-diaminoadamantane (1,6-aminopentacyclo[7.3.1.1 4,12 ,0 2,7 .0 6,11 ] tetradecane) and other alicyclic diamines; tetramethylenediamine, hexamethylenediamine and other aliphatic diamines, etc.

[0100] In the present invention, the amount of the aromatic diamine in the total diamine components is preferably 70 mol% or more, more preferably 80 mol% or more, further preferably 90 mol% or more, and further preferably 95 mol% or more. In addition, in particular, when the diamine represented by formula (S) is used together with the aromatic diamine, the amount of the aromatic diamine in the total amount of the aromatic diamine and the diamine represented by formula (S) is preferably 80 mol% or more, more preferably 90 mol% or more, further preferably 95 mol% or more, and further preferably 97 mol% or more. By adopting such an amount, a film having excellent adhesion to the substrate and moderate adhesion and moderate peelability to the resin substrate can be obtained with good reproducibility.

[0101] The feed ratio of the diamine component to the tetracarboxylic dianhydride component is appropriately determined in consideration of the target molecular weight, molecular weight distribution, type of diamine, type of tetracarboxylic dianhydride, etc., and therefore cannot be generally specified. In order to obtain the polyamic acid of (1) above, the molar number of the tetracarboxylic dianhydride component is preferably slightly larger than the molar number of the diamine component. As a specific molar ratio, the tetracarboxylic dianhydride component is preferably 1.05 to 2.5 moles, more preferably 1.07 to 1.5 moles, and further preferably 1.1 to 1.3 moles, relative to 1 mole of the diamine component.

[0102] The polyamic acid of the above-described formula (1) contained in the release layer-forming composition of the present invention can be obtained by reacting the diamine component and the tetracarboxylic dianhydride component described above.

[0103] The organic solvent used in the synthesis of polyamic acid is not particularly limited as long as it does not have an adverse effect on the reaction. Specific examples thereof include meta-cresol, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, 3-ethoxy-N,N-dimethylpropionamide, 3-propoxy-N,N-dimethylpropionamide, 3-isopropoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, 3-sec-butoxy-N,N-dimethylpropionamide, 3-tert-butoxy-N,N-dimethylpropionamide, γ-butyrolactone, etc. It should be noted that the organic solvent can be used alone or in combination of two or more.

[0104] The reaction temperature during the synthesis of the polyamic acid can be appropriately set within the range of the melting point to the boiling point of the solvent used, and is usually about 0 to 100° C. From the viewpoint of preventing imidization in the obtained polyamic acid solution and maintaining a high content of polyamic acid units, it can be preferably set to about 0 to 70° C., more preferably set to about 0 to 60° C., and further preferably set to about 0 to 50° C. The reaction time cannot be generally specified because it depends on the reaction temperature and the reactivity of the raw materials, but is usually about 1 to 100 hours.

[0105] The weight average molecular weight of the polyamic acid of the formula (1) obtained in this way is usually about 5,000 to 500,000, preferably about 10,000 to 200,000, and more preferably about 30,000 to 150,000 from the viewpoint of improving the function of the obtained film as a release layer. It should be noted that in the present invention, the weight average molecular weight is a polystyrene conversion value obtained by gel permeation chromatography (GPC).

[0106] Specific examples of the polyamic acid that can be preferably used in the present invention include polyamic acids represented by the following formula, but the present invention is not limited thereto.

[0107] [Chemistry 15]

[0108]

[0109] (In the formula, m has the same meaning as above.)

[0110] The peeling layer forming composition of the present invention contains an organic solvent. As the organic solvent, the same organic solvent as the specific example of the reaction solvent in the above reaction can be used, but from the perspective of good dissolution of the polyamic acid of the above formula (1) and easy preparation of a composition with high uniformity, it is particularly preferred to contain at least one selected from the group consisting of amides represented by the following formula (S1), amides represented by the formula (S2), and amides represented by the formula (S3).

[0111] [Chemistry 16]

[0112]

[0113] In the above formula, R 25 and R 26 R independently represents an alkyl group having 1 to 10 carbon atoms. 27 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. b represents a natural number, preferably a natural number of 1 to 5, and more preferably a natural number of 1 to 3.

[0114] Specific examples of the alkyl group having 1 to 10 carbon atoms include the same examples as described above.

[0115] Specific examples of the organic solvent represented by the above formulas (S1) to (S3) include 3-methoxy-N,N-dimethylpropionamide, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, N,N-dimethylbutyramide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, etc., among which N-methyl-2-pyrrolidone is preferred. These organic solvents can be used alone or in combination of two or more.

[0116] Furthermore, even if it is a solvent that does not dissolve polyamic acid in the case of being alone, as long as it is the scope that polyamic acid does not precipitate, it can also be used for the preparation of the composition. Especially, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2-(2-ethoxy propoxy) propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isopentyl lactate, etc. can be appropriately mixed with solvents with low surface tension. It is known that the coating uniformity is improved during coating on the substrate, and it can also be preferably used in the present invention.

[0117] The peeling layer forming composition of the present invention can be prepared by a common method. As a preferred example of the preparation method, the reaction solution containing the target polyamic acid obtained by the method described above can be filtered, and the concentration of the obtained filtrate can be made into a predetermined concentration using the above-mentioned organic solvent. By adopting such a method, not only can the mixing of impurities that may cause the deterioration of the adhesion and peelability of the peeling layer manufactured from the obtained composition be reduced, but also the peeling layer forming composition can be obtained efficiently.

[0118] The concentration of the polyamic acid of the above formula (1) in the peeling layer forming composition of the present invention is appropriately set in consideration of the thickness of the peeling layer to be produced, the viscosity of the composition, etc., and is generally about 1 to 30% by mass, preferably about 1 to 20% by mass. By making it such a concentration, a peeling layer with a thickness of about 0.05 to 5 μm can be obtained with good reproducibility. The concentration of the polyamic acid of the above formula (1) can be adjusted by adjusting the amount of the diamine component and the tetracarboxylic dianhydride component used as the raw materials of the polyamic acid, adjusting the amount of the separated polyamic acid of the above formula (1) when it is dissolved in a solvent, etc.

[0119] The viscosity of the release layer forming composition of the present invention is appropriately set in consideration of the thickness of the release layer to be produced, and is generally about 10 to 10,000 mPa·s, preferably about 20 to 5,000 mPa·s at 25°C, particularly when the purpose is to obtain a film with a thickness of about 0.05 to 5 μm with good reproducibility.

[0120] The viscosity can be measured using a commercially available viscometer for measuring the viscosity of liquids, for example, with reference to the procedure described in JIS K7117-2, under the condition that the temperature of the composition is 25° C. Preferably, as the viscometer, a cone-plate type (cone-plate type) rotational viscometer is used, and preferably, this type of viscometer uses 1°34'×R24 as a standard cone rotor, and can be measured under the condition that the temperature of the composition is 25° C. As such a rotational viscometer, for example, TVE-25L manufactured by Toki Sangyo Co., Ltd. can be cited.

[0121] Furthermore, the release layer forming composition of the present invention may contain a crosslinking agent or the like in addition to the polyamic acid of the above formula (1) and the organic solvent, for example, in order to improve the film strength.

[0122] By applying the release layer forming composition of the present invention described above to a substrate, heating the obtained coating film and thermally imidizing the polyamic acid of the above formula (1), a release layer comprising a polyimide film having excellent adhesion to the substrate and moderate adhesion to the resin substrate and moderate releasability can be obtained.

[0123] When the release layer of the present invention is formed on a substrate, the release layer may be formed on a portion of the substrate surface or on the entire surface. As a form of forming the release layer on a portion of the substrate surface, there are forms in which the release layer is formed only in a predetermined range on the substrate surface, forms in which the release layer is formed in a pattern such as a dot pattern, a line and a gap pattern on the entire substrate surface, and the like. In the present invention, the substrate means a member on the surface of which the release layer forming composition of the present invention is applied and used for the manufacture of flexible electronic devices and the like.

[0124] As the substrate (base material), for example, glass, plastic (polycarbonate, polymethacrylate, polystyrene, polyester, polyolefin, epoxy, melamine, triacetyl cellulose, ABS, AS, norbornene resin, etc.), metal (silicon wafer, etc.), wood, paper, stone slab, etc. can be listed. In the present invention, in particular, from the perspective of sufficient adhesion of the peeling layer, a glass substrate can be preferably used. Furthermore, the substrate surface can be composed of a single material or of two or more materials. As a form in which the substrate surface is composed of two or more materials, there is a form in which a certain range of the substrate surface is composed of one material and the remaining range is composed of other materials; a form in which a certain material is present in other materials in a pattern such as a dot pattern, a line and a gap pattern in the entire substrate surface, etc.

[0125] There is no particular limitation on the method for applying the peeling layer forming composition of the present invention to a substrate, and examples thereof include cast coating, spin coating, blade coating, dip coating, roller coating, rod coating, die coating, inkjet, printing (letterpress, gravure, lithography, screen printing, etc.), and the like.

[0126] The heating temperature for imidization is usually appropriately determined within the range of 50 to 550°C, preferably greater than 150°C and less than 510°C. By setting the heating temperature to such a temperature, the brittleness of the obtained film can be prevented, and the imidization reaction can be fully carried out. The heating time varies depending on the heating temperature, so it cannot be generally specified, and is usually 5 minutes to 5 hours. In addition, the imidization rate can be in the range of 50 to 100%.

[0127] As a preferred example of the heating method in the present invention, the following method can be cited: after heating at 50 to 150° C. for 5 minutes to 2 hours, the heating temperature is gradually increased, and finally heating at a temperature greater than 150° C. and less than 510° C. for 30 minutes to 4 hours. Particularly preferably, after heating at 50 to 150° C. for 5 minutes to 2 hours, heating at a temperature greater than 150° C. and less than 350° C. for 5 minutes to 2 hours, and finally heating at a temperature greater than 350° C. and less than 450° C. for 30 minutes to 4 hours.

[0128] Examples of the apparatus used for heating include a hot plate, an oven, etc. The heating atmosphere may be air or an inert gas, and may be normal pressure or reduced pressure.

[0129] The thickness of the release layer is usually about 0.01 to 50 μm, and preferably about 0.05 to 20 μm from the viewpoint of productivity. The desired thickness can be achieved by adjusting the thickness of the coating film before heating.

[0130] The peeling layer described above has excellent adhesion to a substrate, especially a glass substrate, and moderate adhesion to a resin substrate, and moderate peeling properties, and further, these properties do not change before and after a heat treatment, especially in a TFT process, and the performance is stable. Therefore, the peeling layer of the present invention can be suitably used for peeling the resin substrate from the substrate together with the circuit formed on the resin substrate, etc., without damaging the resin substrate of the device in the manufacturing process of the flexible electronic device.

[0131] An example of a method for producing a flexible electronic device using the release layer of the present invention is described below.

[0132] Using the peeling layer forming composition of the present invention, a peeling layer is formed on a glass substrate by the above-mentioned method. A resin solution for forming a resin substrate is applied to the peeling layer, and the coating is heated, thereby forming a resin substrate fixed to the glass substrate via the peeling layer of the present invention. At this time, the substrate is formed in an area larger than the area of ​​the peeling layer in a manner that the peeling layer is completely covered. As the resin substrate, a resin substrate made of polyimide, which is a representative resin substrate for flexible electronic devices, can be listed, and as the resin solution for forming it, a polyimide solution and a polyamic acid solution can be listed. The method for forming the resin substrate can be according to a conventional method.

[0133] Next, a desired circuit is formed on the resin substrate fixed to the base via the peeling layer of the present invention, and then, for example, the resin substrate is cut along the peeling layer, and the resin substrate is peeled off from the peeling layer together with the circuit to separate the resin substrate from the base. At this time, a part of the base may be cut together with the peeling layer.

[0134] Furthermore, Japanese Patent Publication No. 2013-147599 reported that the laser lift-off method (LLO method) that has been used in the manufacture of high-brightness LEDs, three-dimensional semiconductor packages, etc., is applied to the manufacture of flexible displays. The above-mentioned LLO method is characterized in that a light of a specific wavelength, such as a light of a wavelength of 308 nm, is irradiated from the glass substrate side from the opposite side of the surface on which the circuit is formed. The irradiated light passes through the glass substrate, and only the polymer (polyimide) near the glass substrate absorbs the light and evaporates (sublimates). As a result, the resin substrate can be selectively peeled off from the glass substrate without affecting the circuit provided on the resin substrate that determines the performance of the display.

[0135] The composition for forming a peeling layer of the present invention has the characteristic of fully absorbing light of a specific wavelength (e.g., 308 nm) to which the above-mentioned LLO method can be applied, and therefore can be used as a sacrificial layer of the LLO method. Therefore, in the present invention, a desired circuit is formed on a resin substrate fixed to a glass substrate via a peeling layer formed by using the composition, and then, the LLO method is implemented to irradiate 308 nm light, and only the peeling layer absorbs the light and evaporates (sublimates). Thus, the above-mentioned peeling layer is sacrificed (functions as a sacrificial layer), and the resin substrate can be selectively peeled off from the glass substrate.

[0136] Example

[0137] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0138] [1] Abbreviation of the compound

[0139] p-PDA: p-phenylenediamine

[0140] BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride

[0141] PMDA: Pyromellitic Dianhydride

[0142] NMP: N-methyl-2-pyrrolidone

[0143] BCS: Butyl Cellosolve

[0144] [2] Method for determining weight average molecular weight and molecular weight distribution

[0145] The weight average molecular weight (hereinafter abbreviated as Mw) and molecular weight distribution of the polymer were measured using a GPC apparatus manufactured by JASCO Corporation (columns: KD801 and KD805 manufactured by Shodex; eluent: dimethylformamide / LiBr·H2O (29.6 mM) / H3PO4 (29.6 mM) / THF (0.1 wt%); flow rate: 1.0 mL / min; column temperature: 40°C; Mw: standard polystyrene conversion value).

[0146] [3] Synthesis of polymers

[0147] Polyamic acid was synthesized by the following method.

[0148] In addition, the polymer is not isolated from the obtained reaction solution containing the polymer, and the resin substrate forming composition or the release layer forming composition is prepared by diluting the reaction solution as described later.

[0149] <Synthesis Example S1 Synthesis of polyamic acid (S1)>

[0150] 3.218 g (30 mmol) of p-PDA was dissolved in 88.2 g of NMP. 8.581 g (29 mmol) of BPDA was added to the obtained solution, and the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere. The obtained polymer had an Mw of 107,300 and a molecular weight distribution of 4.6.

[0151] <Synthesis Example L1 Synthesis of polyamic acid (L1)>

[0152] 4.47 g (41.4 mmol) of p-PDA was dissolved in 132 g of NMP. 13.53 g (46.0 mmol) of BPDA was added to the obtained solution, and the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere. The obtained polymer had an Mw of 75,400 and a molecular weight distribution of 3.3.

[0153] <Synthesis Example L2 Synthesis of polyamic acid (L2)>

[0154] 5.55 g (51.4 mmol) of p-PDA was dissolved in 132 g of NMP. 12.45 g (57.1 mmol) of PMDA was added to the obtained solution, and the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere. The obtained polymer had an Mw of 76,400 and a molecular weight distribution of 2.2.

[0155] <Synthesis Example L3 Synthesis of polyamic acid (L3)>

[0156] 2.73 g (25.2 mmol) of p-PDA was dissolved in 88 g of NMP. 9.27 g (31.5 mmol) of BPDA was added to the obtained solution, and the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere. The obtained polymer had an Mw of 45,000 and a molecular weight distribution of 3.9.

[0157] <Comparative Synthesis Example B1 Synthesis of Polyamic Acid (B1)>

[0158] 20.8 g (192 mmol) of p-PDA was dissolved in 425 g of NMP. 54.2 g (184 mmol) of BPDA was added to the obtained solution, and the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere. The obtained polymer had an Mw of 69,200 and a molecular weight distribution of 2.2.

[0159] [4] Preparation of a composition for forming a resin substrate

[0160] [Preparation Example 1]

[0161] The reaction liquid obtained in Synthesis Example S1 was used as a composition for forming a resin substrate as it was.

[0162] [5] Preparation of peeling layer forming composition

[0163] [Example 1-1]

[0164] BCS and NMP were added to the reaction solution obtained in Synthesis Example L1, and the mixture was diluted so that the polymer concentration became 5% by mass and the BCS became 20% by mass to obtain a release layer-forming composition.

[0165] [Examples 1-2 to 1-3]

[0166] A release layer forming composition was obtained in the same manner as in Example 1-1 except that the reaction solution obtained in Synthesis Example L1 was replaced with the reaction solution obtained in Synthesis Examples L2 to L3, respectively.

[0167] [Comparative Example 1-1]

[0168] A release layer forming composition was obtained in the same manner as in Example 1-1 except that the reaction solution obtained in Synthesis Example L1 was used instead of the reaction solution obtained in Comparative Synthesis Example B1.

[0169] [6] Fabrication of peeling layer and resin substrate

[0170] [Example 2-1]

[0171] The release layer forming composition obtained in Example 1-1 was applied onto a 100 mm×100 mm glass substrate (hereinafter the same) as a glass base using a spin coater (conditions: rotation speed 3,000 rpm, about 30 seconds).

[0172] Then, the obtained coating film was heated at 80°C for 10 minutes using a hot plate, and then heated at 300°C for 30 minutes using an oven, and the heating temperature was increased (10°C / minute) to 400°C, and then heated at 400°C for 30 minutes to form a peeling layer with a thickness of about 0.1 μm on the glass substrate, thereby obtaining a glass substrate with a peeling layer. It should be noted that during the heating period, the substrate with the film was not taken out of the oven and was heated in the oven.

[0173] The composition for forming a resin substrate was applied to the peeling layer (resin film) on the glass substrate obtained above using a bar coater (gap: 250 μm). Then, the obtained coating was heated at 80°C for 30 minutes using a hot plate, and then, using an oven, it was heated at 140°C for 30 minutes, the heating temperature was increased (2°C / min, the same below) to 210°C, heated at 210°C for 30 minutes, the heating temperature was increased to 300°C, heated at 300°C for 30 minutes, the heating temperature was increased to 400°C, and heated at 400°C for 60 minutes to form a polyimide substrate with a thickness of about 20 μm on the peeling layer, thereby obtaining a glass substrate with a resin substrate and peeling layer. During the heating period, the substrate with the film was not taken out of the oven and was heated in the oven.

[0174] [Examples 2-2 to 2-3]

[0175] A glass substrate with a peeling layer and a glass substrate with a resin substrate and a peeling layer were obtained by preparing a peeling layer and a polyimide substrate by the same method as in Example 2-1, except that the peeling layer forming composition obtained in Examples 1-2 to 1-3 was used instead of the peeling layer forming composition obtained in Example 1-1.

[0176] [Comparative Example 2-1]

[0177] A glass substrate with a peeling layer and a glass substrate with a resin substrate and a peeling layer were obtained by preparing a peeling layer and a polyimide substrate by the same method as in Example 2-1, except that the peeling layer forming composition obtained in Comparative Example 1-1 was used instead of the peeling layer forming composition obtained in Example 1-1.

[0178] [7] Evaluation of peelability

[0179] The peelability between the peeling layer and the glass substrate was confirmed by the following method for the glass substrate with the peeling layer obtained in Examples 2-1 to 2-3 and Comparative Example 2-1. The following test was performed using the same glass substrate.

[0180] <Evaluation of peelability of resin film by cross-cut test>

[0181] The release layer on the glass substrate with a release layer obtained in Examples 2-1 to 2-3 and Comparative Example 2-1 was cross-cut (1 mm interval vertically and horizontally, the same below) to form 100 grids. That is, the cross-cutting formed 100 1 mm square grids.

[0182] Then, tape was attached to the 100 grid-cut portions, the tape was peeled off, and the degree of peeling was evaluated based on the following criteria (5B to 0B, B, A, AA).

[0183] <Judgment Criteria>

[0184] 5B: 0% peeling (no peeling)

[0185] 4B: Less than 5% divestiture

[0186] 3B: 5% to 15% peeling

[0187] 2B: 15% or more and less than 35% of peeling

[0188] 1B: 35% or more but less than 65% of the peeling

[0189] 0B: 65% or more and less than 80% peeling

[0190] B: 80% or more and less than 95% peeling

[0191] A: 95% or more but less than 100% peeling

[0192] AA: 100% peeling (full peeling)

[0193] <Evaluation of initial peeling force of resin substrate>

[0194] The resin substrate of the glass substrate with a resin substrate peeling layer obtained in Examples 2-1 to 2-3 and Comparative Example 2-1 was cut into a 25 mm wide strip using a cutting tool. Then, a transparent tape was pasted on the front end of the cut resin substrate to serve as a test piece. For the test piece, a peeling test was performed using a push-pull tester manufactured by Atonic (Strain) in a manner where the peeling angle was 90°, and the peeling force was evaluated based on the following standards. The results are shown in Table 1.

[0195] <Judgment Criteria>

[0196] 4b: No stripping

[0197] 3b: Peel force above 1.00 (N / 25mm)

[0198] 2b: Peel force of 0.80 (N / 25mm) or more and less than 1.00 (N / 25mm)

[0199] 1b: Peel force of 0.60 (N / 25mm) or more and less than 0.80 (N / 25mm)

[0200] 0b: Peel force of 0.40 (N / 25mm) or more and less than 0.60 (N / 25mm)

[0201] b: Peel force of 0.30 (N / 25mm) or more and less than 0.40 (N / 25mm)

[0202] a: Peel force of 0.20 (N / 25mm) or more and less than 0.30 (N / 25mm)

[0203] aa: Peel force less than 0.20 (N / 25mm)

[0204] <Evaluation of peeling strength of resin substrate subjected to high temperature treatment>

[0205] The resin substrates of Examples 2-1 to 2-3 and Comparative Example 2-1, which were used to evaluate the initial peeling force, were heated in an oven at 400°C for 6 hours to perform the same high-temperature treatment as in the TFT process. Then, a 90° peeling test of the resin substrate was performed in the same manner as in the initial peeling force evaluation. The obtained peeling force was evaluated based on the same criteria as in the initial peeling force.

[0206] <Evaluation of Peel Force Change>

[0207] The change in the peel force before and after the high temperature treatment was calculated according to the following formula. Then, the degree of the change in the peel force was evaluated based on the following criteria. The results are recorded in Table 1.

[0208] Change (%) = {(peeling force after high temperature treatment) - (peeling force before high temperature treatment)} / (peeling force before high temperature treatment) × 100

[0209] ○: Less than 40% change in peeling force (good peeling)

[0210] △: Peel force change of 40% or more and less than 70%

[0211] ×: Peel force change of 70% or more and less than 100%

[0212] ××: Change in peel force of 100% or more (deterioration in peel force)

[0213] [Table 1]

[0214]

[0215] As shown in Table 1, it can be seen that the release layer of the example has no change in release force even after the high temperature treatment.

[0216] On the other hand, it was found that the release layer of Comparative Example 2-1 was excellent in adhesion to the glass substrate and in releasability from the resin substrate, but the release force was deteriorated after the high-temperature treatment.

Claims

1. A method for manufacturing a flexible electronic device, comprising the following steps: A peeling layer is formed on a glass substrate using a peeling layer forming composition, a resin solution for forming a resin substrate is applied on the peeling layer, and the coating film is heated to form a resin substrate fixed to the glass substrate via the peeling layer, and then a desired circuit is formed on the resin substrate, and then the resin substrate is peeled off from the peeling layer together with the circuit to separate the resin substrate from the substrate, The release layer forming composition is characterized by comprising: a polyamic acid represented by the following formula (1) and an organic solvent. [Chemistry 1] In the formula, X represents an aromatic group represented by the following formula (2) or (3), Y represents a divalent aromatic group, Z represents an aromatic group represented by the following formula (4) or (5) when X is an aromatic group represented by the following formula (2), and represents an aromatic group represented by the following formula (6) or (7) when X is an aromatic group represented by the following formula (3), and m represents a natural number. [Chemistry 2] [Chemistry 3] , The polyamic acid represented by the formula (1) is obtained by reacting a tetracarboxylic dianhydride component with a diamine component. The feed ratio of the diamine component and the tetracarboxylic dianhydride component is 1.05 to 2.5 mol of the tetracarboxylic dianhydride component relative to 1 mol of the diamine component as a molar ratio.

2. The method for manufacturing a flexible electronic device according to claim 1, wherein: The X is an aromatic group represented by the following formula (8) to (11); the Z is an aromatic group represented by the following formula (12) or (13) when X is an aromatic group represented by the following formula (8) or (9); and is an aromatic group represented by the following formula (14) or (15) when X is an aromatic group represented by the following formula (10) or (11); [Chemistry 4] [Chemistry 5] .

3. The method for manufacturing a flexible electronic device according to claim 1 or 2, wherein: The Y is a divalent aromatic group containing 1 to 5 benzene rings.

4. The method for manufacturing a flexible electronic device according to claim 3, wherein: The Y is at least one selected from the following formulas (16) to (18), [Chemistry 6] In the formula, R 1 ~R 24 Each of them independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, or an alkyl group having 1 to 20 carbon atoms which may be substituted by a halogen atom, an alkenyl group having 2 to 20 carbon atoms which may be substituted by a halogen atom, an alkynyl group having 2 to 20 carbon atoms which may be substituted by a halogen atom, an aryl group having 6 to 20 carbon atoms which may be substituted by a halogen atom, or a heteroaryl group having 2 to 20 carbon atoms which may be substituted by a halogen atom.

5. The method for manufacturing a flexible electronic device according to claim 4, wherein: The R 1 ~R 24 For hydrogen.

6. The method for manufacturing a flexible electronic device according to claim 1 or 2, wherein: The m is a natural number less than 100.

7. The method for manufacturing a flexible electronic device according to claim 1 or 2, wherein: The organic solvent includes at least one selected from the group consisting of amides represented by formula (S1), amides represented by formula (S2), and amides represented by formula (S3), [Chemistry 7] In the formula, R 25 and R 26 are independently an alkyl group having 1 to 10 carbon atoms, R 27 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and b represents a natural number.

8. The method for manufacturing a flexible electronic device according to claim 1 or 2, wherein: The resin substrate is a substrate including polyimide.

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