KR102500563B1 - Composition for Forming a Substrate Protection Layer - Google Patents

Abstract

After forming the resin substrate on the substrate, when the resin substrate is peeled off to produce the resin substrate, the resin substrate after peeling is interposed between the substrate and the resin substrate and has easy releasability from the substrate. As a composition for forming a protective layer for a substrate that functions as a protective layer of, a composition for forming a protective layer for a substrate containing a polyamic acid and an organic solvent is provided.

Description

Composition for Forming a Substrate Protection Layer

The present invention relates to a composition for forming a substrate protective layer.

BACKGROUND ART [0002] In recent years, electronic devices have been required to have a bendable function in addition to thinning and lightening characteristics. In this regard, it is desired to use a lightweight, flexible plastic substrate in place of the conventional heavy, brittle, and unbendable glass substrate.

In particular, in a new generation display, development of an active matrix type full color TFT display panel using a lightweight flexible plastic substrate (hereinafter referred to as a resin substrate) is required. Technology related to this new generation display is expected to be diverted to various fields such as flexible displays, flexible smartphones, and mirror displays.

Then, various methods of manufacturing an electronic device using a resin film as a substrate have begun to be examined, and examination of a process in which existing facilities for manufacturing TFT display panels can be diverted is progressing in a new generation display.

For example, in Patent Documents 1, 2 and 3, an amorphous silicon thin film layer is formed on a glass substrate, a plastic substrate is formed on the thin film layer, and then a laser is irradiated from the glass substrate side to crystallize the amorphous silicon, and the crystallization A method of peeling a plastic substrate from a glass substrate by hydrogen gas generated according to the method is disclosed.

In addition, Patent Document 4 discloses a method of completing a liquid crystal display device by attaching a layer to be peeled (referred to as "transferred layer" in Patent Document 4) to a plastic film using the technology disclosed in Patent Documents 1 to 3 has been

However, in the method disclosed in Patent Literatures 1 to 4, particularly in the method disclosed in Patent Literature 4, it is essential to use a substrate having high light transmission properties in order to transmit laser light, and hydrogen contained in amorphous silicon is released through the substrate. There are problems such as requiring irradiation with a laser beam having a relatively high energy enough to achieve this, and that the layer to be separated may be damaged by irradiation with the laser beam.

In addition, when the layer to be separated has a large area, it is difficult to increase the productivity of device fabrication because the laser treatment requires a long time.

As a means to solve such a problem, in Patent Document 5, a current glass substrate is used as a base (hereinafter referred to as a glass base), and a polymer such as a cyclic olefin copolymer is used on the glass base to form a release layer After forming a heat-resistant resin film (resin substrate) such as a polyimide film on the peeling layer, forming and sealing ITO transparent electrodes, TFTs, etc. on the film by a vacuum process, and finally peeling and removing the glass substrate. manufacturing process is employed.

By the way, currently, low-temperature polysilicon TFTs are used as TFTs, which are twice as fast in mobility as compared to amorphous silicon TFTs. This low-temperature polysilicon TFT requires dehydrogenation annealing at 400° C. or higher after deposition of amorphous silicon, irradiation with a pulsed laser to crystallize silicon (hereinafter, these are referred to as TFT processes), and the temperature of the dehydrogenation annealing process is It is higher than the glass transition temperature (hereinafter referred to as Tg) of existing polymers.

However, conventional polymers are known to have high adhesion when heated to a temperature higher than Tg (for example, see Patent Document 6), and after heat treatment, adhesion between the release layer and the substrate and the resin substrate increases, and the resin substrate is separated from the substrate. There was a case where it became difficult to peel from the .

In addition, heat-resistant polymers applicable to such a process are limited to some highly heat-resistant polymer compounds such as polyimide, but cannot be dissolved in general solvents. For this reason, when the polyimide was used for the release layer, it was difficult to reuse the glass substrate by removing the release layer remaining in the glass substrate after peeling the resin substrate.

Japanese Unexamined Patent Publication No. 10-125929 Japanese Unexamined Patent Publication No. 10-125931 International Publication No. 2005/050754 Japanese Unexamined Patent Publication No. 10-125930 Japanese Unexamined Patent Publication No. 2010-111853 Japanese Unexamined Patent Publication No. 2008-188792

The present invention has been made in view of the above circumstances, and in addition to making it easy to reuse the base, it can be separated from the base together with the resin substrate of the flexible electronic device, and even damaging the resin substrate, significantly changing the characteristics It is an object of the present invention to provide a composition for forming a protective layer for a substrate that is not required.

As a result of intensive studies to solve the above problems, the present inventors have found that after forming a resin substrate on a substrate, when the resin substrate is peeled off to produce a resin substrate, interposed between the substrate and the resin substrate, By using a composition containing a polyamic acid and an organic solvent as a composition for forming a substrate protective layer that has easy releasability from the substrate and functions as a protective layer of a resin substrate after peeling, It was found that a substrate protective layer having appropriate adhesion, appropriate peelability, and excellent adhesion to a resin substrate used for flexible electronic devices could be formed, and the present invention was completed.

That is, the present invention

1. After a resin substrate is formed on a substrate, when the resin substrate is separated from the substrate together with the resin substrate, it is interposed between the substrate and the resin substrate, and has easy separation from the substrate. In addition, a composition for forming a protective layer for a substrate that functions as a protective layer for the resin substrate after peeling, comprising a polyamic acid and an organic solvent;

2. A composition for forming a substrate protective layer of 1 containing 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), Y represents a divalent aromatic group having a fluorine atom, and n represents a natural number.)

3. The composition for forming a substrate protective layer of 2, wherein Y is an aromatic group represented by the following formula (3),

4. The composition for forming a substrate protective layer of 2 or 3, wherein Y is an aromatic group represented by the following formula (4),

5. The composition for forming a substrate protective layer of any one of 1 to 4, wherein the organic solvent is at least one selected from those having structures represented by the following formulas (S1) to (S7);

(Wherein, R ¹ to R ⁸ independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ⁹ and R ¹⁰ are independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms) represents an acyl group of, and b and n represent natural numbers)

6. When an electronic device is further produced on the resin substrate and the electronic device is peeled from the substrate together with the resin substrate, it has easy releasability from the substrate and functions as a protective layer of the resin substrate after peeling The composition for forming a substrate protective layer of 1,

7. A substrate protective layer obtained from the composition for forming a substrate protective layer of any one of 1 to 6;

8. A step of applying the composition for forming a substrate protective layer of 6 on a substrate and firing it at a maximum temperature of 500° C. or higher to form a substrate protective layer having easy releasability from the substrate;

A step of applying a composition for forming a resin substrate on the substrate protective layer and firing it at a maximum temperature of 500° C. or higher to form a resin substrate;

A step of manufacturing an electronic device on the resin substrate;

A method for manufacturing a flexible electronic device comprising a step of peeling the electronic device together with the substrate protective layer and the resin substrate from the substrate;

9. The manufacturing method of the flexible electronic device of 8, wherein the resin substrate is a polyimide resin substrate;

10. After applying the composition for forming a substrate protective layer of any one of 1 to 5 on a substrate and firing at a maximum temperature of 500 ° C or higher to form a substrate protective layer, the composition for forming a resin substrate is applied on the substrate protective layer A method for producing a resin substrate with a protective layer, characterized by applying and firing at a maximum temperature of 500° C. or higher to form a resin substrate, and then peeling the resin substrate together with the substrate protective layer from the substrate;

11. Manufacturing method of 10, wherein the resin substrate is a polyimide resin substrate

provides

By using the composition for forming a substrate protective layer of the present invention, a substrate protective layer having appropriate adhesion to a substrate, appropriate peelability, and excellent adhesion to a resin substrate can be obtained with good reproducibility. Therefore, in the manufacturing process of a flexible electronic device, by using the composition for forming a substrate protective layer of the present invention, without damaging the resin substrate formed on the substrate or the circuit further installed thereon, etc. together with the circuit etc. It becomes possible to separate the resin substrate and the substrate protective layer from the substrate. Therefore, the composition for forming a protective layer for a substrate of the present invention can promote reuse of a gas, and can contribute to simplifying a manufacturing process of a flexible electronic device having a resin substrate or improving its yield.

Hereinafter, the present invention will be described in more detail.

The composition for forming a substrate protective layer of the present invention includes polyamic acid and an organic solvent. Here, the substrate protective layer in the present invention is a layer provided directly on the glass substrate for a predetermined purpose, and as a typical example thereof, in the manufacturing process of a flexible electronic device, a substrate and a flexible electronic device made of a resin such as polyimide A layer provided between the resin substrate and the resin substrate in order to fix the resin substrate during a predetermined process is exemplified. In addition, this substrate protective layer is different from the conventional release layer in that it is separated from the substrate together with the resin substrate after the electronic circuit or the like is formed on the resin substrate.

As the diamine component and the acid dianhydride component used in the production of polyamic acid, they have the property of being separated from the substrate together with the resin substrate after the above-mentioned manufacturing process, that is, they have easy releasability from the substrate and also have adhesion to the resin substrate. It is not particularly limited as long as it is applied with a polyimide film, but from the viewpoint of sufficiently exhibiting the properties of easy release from the substrate and adhesion to a resin substrate, a diamine component containing an aromatic diamine and an aromatic tetracarboxylic dianhydride are contained. A polyamic acid obtained by reacting an acid dianhydride component to be used is preferable, and in particular, a polyamic acid obtained by using a biphenyltetracarboxylic dianhydride represented by the following formula (1) and an aromatic diamine having a fluorine atom. Suitable.

In formula (1), X represents an aromatic group derived from biphenyltetracarboxylic acid represented by the following formula (2), and Y represents a divalent fluorine atom-containing aromatic group derived from an aromatic diamine having a fluorine atom.

Although n represents a natural number, an integer of 2 or more is preferable.

Examples of the biphenyltetracarboxylic dianhydride giving a bivalent group derived from biphenyltetracarboxylic acid represented by the above formula (2) include those represented by the following formulas (C1) to (C3), in the present invention In particular, 3,3',4,4'-biphenyltetracarboxylic dianhydride represented by formula (C1) is suitable. Moreover, (C1)-(C3) may be used independently, respectively, and may be used in combination of 2 or more types.

Moreover, in addition to the said biphenyl tetracarboxylic acid dianhydride, other tetracarboxylic acid dianhydride can also be used in this invention.

Specific examples thereof include pyromellitic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, naphthalene-1,2,3,4-tetracarboxylic dianhydride, and naphthalene-1,2,5 ,6-tetracarboxylic dianhydride, naphthalene-1,2,6,7-tetracarboxylic dianhydride, naphthalene-1,2,7,8-tetracarboxylic dianhydride, naphthalene-2,3, 5,6-tetracarboxylic dianhydride, naphthalene-2,3,6,7-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, anthracene-1,2 ,3,4-tetracarboxylic dianhydride, anthracene-1,2,5,6-tetracarboxylic dianhydride, anthracene-1,2,6,7-tetracarboxylic dianhydride, anthracene-1, 2,7,8-tetracarboxylic dianhydride, anthracene-2,3,6,7-tetracarboxylic dianhydride, phenanthrene-1,2,3,4-tetracarboxylic dianhydride, phenanthrene -1,2,5,6-tetracarboxylic dianhydride, phenanthrene-1,2,6,7-tetracarboxylic dianhydride, phenanthrene-1,2,7,8-tetracarboxylic dianhydride Water, phenanthrene-1,2,9,10-tetracarboxylic dianhydride, phenanthrene-2,3,5,6-tetracarboxylic dianhydride, phenanthrene-2,3,6,7-tetra Carboxylic dianhydride, phenanthrene-2,3,9,10-tetracarboxylic dianhydride, phenanthrene-3,4,5,6-tetracarboxylic dianhydride, phenanthrene-3,4,9 , 10-tetracarboxylic dianhydride etc. are mentioned, These can also be used individually or in combination of 2 or more types.

In the polyamic acid used in the present invention, the amount of biphenyltetracarboxylic dianhydride in the tetracarboxylic acid component is 70 mol%, considering that the above-described easy releasability from the substrate and adhesion to the resin substrate are compatible. The above is preferable, 80 mol% or more is more preferable, 90 mol% or more is still more preferable, 95 mol% or more is still more preferable, and 100 mol% is most preferable.

On the other hand, as specific examples of the aromatic diamine having a fluorine atom giving Y, 5-trifluoromethylbenzene-1,3-diamine, 5-trifluoromethylbenzene-1,2-diamine, 3,5-bis( Trifluoromethyl) benzene-1,2-diamine, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-bis (trifluoromethyl) benzidine) , 3,3'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (3,3'-bis (trifluoromethyl) benzidine), 2,2-bis (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 3,3 '-bis(trifluoromethyl)biphenyl-4,4'-diamine, 3,3',5,5'-tetrafluorobiphenyl-4,4'-diamine, 4,4'-diaminooctafluoro Robiphenyl etc. are mentioned, These may be used independently or may be used in combination of 2 or more types.

Among these, in consideration of achieving both the easy releasability from the substrate and the adhesion to the resin substrate described above, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2 '-bis (trifluoromethyl) benzidine), 3,3'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (3,3'-bis (trifluoromethyl) benzidine) It is preferred, and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (2,2'-bis(trifluoromethyl)benzidine) is even more preferred.

Therefore, suitable examples of Y in formula (1) include divalent aromatic groups represented by formulas (3) and (4).

Moreover, in this invention, other diamine can also be used in addition to the said aromatic diamine which has a fluorine atom.

Specific examples thereof 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-xylylenediamine, p- diamines having one benzene nucleus such as xylylenediamine; 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'-biphenyldiamine, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4, 4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminobenzanilide, 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, 3,3'-diaminodiphenylsulfoxide, 3,4'-diaminodiphenylsulfoxide, Two benzene nuclei, such as 4,4'-diaminodiphenylsulfoxide, 2-(3-aminophenyl)-5-aminobenzimidazole, and 2-(4-aminophenyl)-5-aminobenzoxazole diamine; 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-aminophenylsulfide)benzene, 1,3-bis(4-aminophenylsulfide)benzene, 1,4-bis(4- Aminophenylsulfide)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, diamine having three benzene nuclei such as 4,4''-diamino-m-terphenyl, etc. You may use it, and you may use it in combination of 2 or more types.

In the polyamic acid used in the present invention, the amount of aromatic diamine having a fluorine atom in the diamine component is preferably 70 mol% or more, considering that the above-described easy releasability from the gas and adhesion to the resin substrate are compatible. , 80 mol% or more is more preferable, 90 mol% or more is still more preferable, 95 mol% or more is still more preferable, and 100 mol% is most preferable.

The polyamic acid included in the composition for forming a substrate protective layer of the present invention can be obtained by reacting the diamine component and the tetracarboxylic dianhydride component described above in an organic solvent.

The organic solvent used in this reaction is not particularly limited as long as it does not adversely affect the reaction, and specific examples thereof include m-cresol, 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-ethyl-2. -Pyrrolidone, N-vinyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropylamide, 3-ethoxy-N ,N-dimethylpropylamide, 3-propoxy-N,N-dimethylpropylamide, 3-isopropoxy-N,N-dimethylpropylamide, 3-butoxy-N,N-dimethylpropylamide, 3-sec -butoxy-N,N-dimethylpropylamide, 3-tert-butoxy-N,N-dimethylpropylamide, γ-butyrolactone, and the like. In addition, an organic solvent can be used individually by 1 type or in combination of 2 or more types.

Since the introduction ratio (molar ratio) of the diamine component and the tetracarboxylic dianhydride component is determined appropriately in consideration of the target molecular weight, molecular weight distribution, type of diamine, type of tetracarboxylic dianhydride, etc., it cannot be defined collectively, The diamine component is about 0.7 to 1.3, preferably about 0.8 to 1.2, more preferably about 0.9 to 1.1, relative to the tetracarboxylic dianhydride component 1.

The reaction temperature may be appropriately set in the range from the melting point to the boiling point of the solvent to be used, and is usually about 0 to 100 ° C. is about 0 to 70°C, more preferably about 0 to 60°C, still more preferably about 0 to 50°C.

Since the reaction time depends on the reaction temperature and the reactivity of the raw material, it cannot be defined collectively, but it is usually about 1 to 100 hours.

The weight average molecular weight of the polyamic acid obtained in this way is usually about 5,000 to 500,000, but from the viewpoint of improving the function of the obtained film as a substrate protective layer, it is preferably about 10,000 to 200,000, more preferably about 30,000 to 150,000. In addition, in this invention, a weight average molecular weight is a polystyrene conversion value by gel permeation chromatography (GPC) measurement.

In addition, the polyamic acid used in the present invention may further react with an amine having an anchor group or an acid anhydride having an anchor group at one or both of its polymer chain terminals.

Examples of such an anchor group include a carboxylic acid group, a silyl group (eg, an alkylsilyl group, an alkoxysilyl group, a vinylsilyl group, an allylsilyl group, etc.), a vinyl group, a maleimide group, a phenolic hydroxyl group, and the like, Among them, a carboxylic acid group and a silyl group (particularly, a silyl group in which one or more groups selected from an alkoxy group, a vinyl group and an allyl group are bonded to a silicon atom) are preferable.

In addition, between the polyamic acid obtained from the diamine component and the tetracarboxylic dianhydride component and the anchor group, there may be a spacer group such as an alkyl group having about 1 to 10 carbon atoms and a carbon number that does not significantly reduce the peelability or heat resistance, such as an aryl group. .

Specific examples of the amine having an anchor group include 4-aminophenoxytrimethylsilane, 4-aminophenoxydimethylvinylsilane, 4-aminophenoxymethyldivinylsilane, 4-aminophenoxytrivinylsilane, and 4-aminophenoxydimethylallyl. Silane, 4-aminophenoxymethyldiallylsilane, 4-aminophenoxytriallylsilane, 4-aminophenoxydimethylphenylsilane, 4-aminophenoxymethyldiphenylsilane, 4-aminophenoxytriphenylsilane, 4- Aminophenoxytrimethoxysilane, 4-aminophenoxydimethoxyvinylsilane, 4-aminophenoxymethoxydivinylsilane, 4-aminophenoxytrivinylsilane, 4-aminophenoxydimethoxyallylsilane, 4-amino Phenoxymethoxydiallylsilane, 4-aminophenoxydimethoxyphenylsilane, 4-aminophenoxymethoxydiphenylsilane, 4-aminophenoxytriethoxysilane, 4-aminophenoxydiethoxyvinylsilane, 4-aminophenoxy Ethoxydivinylsilane, 4-aminophenoxytrivinylsilane, 4-aminophenoxydiethoxyallylsilane, 4-aminophenoxyethoxydiallylsilane, 4-aminophenoxydiethoxyphenylsilane, 4-amino Phenoxyethoxydiphenylsilane, 3-aminophenoxytrimethylsilane, 3-aminophenoxydimethylvinylsilane, 3-aminophenoxymethyldivinylsilane, 2-aminophenoxytrivinylsilane, 2-aminophenoxytrimethyl Silane, 2-aminophenoxydimethylvinylsilane, 2-aminophenoxymethyldivinylsilane, 2-aminophenoxytrivinylsilane, 3-aminopropyltriethylsilane, 3-aminopropyltrimethoxysilane, 3-amino Propyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltri Ethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 2-aminophenol, 3-aminophenol, 4-aminophenol, etc. are mentioned, but it is not limited to these.

Specific examples of the acid anhydride having an anchor group include trimellitic anhydride, vinylmaleic anhydride, 4-vinylnaphthalene-1,2-dicarboxylic acid anhydride, maleic anhydride, 2,3-dimethylmaleic anhydride, and 4-hydroxyl. Although phthalic anhydride and 3-hydroxyphthalic anhydride are mentioned, it is not limited to these.

In addition, the amount of the amine having an anchor group and the acid anhydride having an anchor group is about 0.01 to 0.6, preferably about 0.05 to 0.4, more preferably about 0.1 to 0.2 of the amine having an anchor group relative to the tetracarboxylic dianhydride component 1 in a molar ratio. , or about 0.01 to 0.52, preferably about 0.05 to 0.32, more preferably about 0.1 to 0.2 of the acid anhydride having an anchor group relative to the diamine component 1.

The composition for forming a substrate protective layer of the present invention contains an organic solvent in addition to the polyamic acid described above. Although it does not specifically limit as this organic solvent, A solvent selected from the following is preferable.

(Wherein, R ¹ to R ⁸ independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ⁹ and R ¹⁰ are independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms) Represents an acyl group of, b and m represent a natural number)

b and m represent natural numbers, but are preferably 1 to 3, more preferably 1 or 2.

Examples of the alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n - A heptyl group, n-octyl group, n-nonyl group, n-decyl group, etc. are mentioned. Among these, an alkyl group having 1 to 3 carbon atoms is preferable, and an alkyl group having 1 or 2 carbon atoms is more preferable.

Examples of the acyl group having 1 to 10 carbon atoms include an alkanoyl group having 1 to 8 carbon atoms (eg, formyl group, acetyl group, propionyl group, butyryl group, isobutyryl group, valeryl group, pivaloyl group, etc.), and 3 to 8 carbon atoms. Cycloalkylcarbonyl group of 6 (eg, cyclopropylcarbonyl group, cyclopentylcarbonyl group, cyclohexylcarbonyl group, etc.), benzoyl group, etc. are mentioned, and an acetyl group is preferable.

Among them, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3 from the viewpoint of easily dissolving polyamic acid and preparing a highly uniform composition. -Dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, and γ-butyrolactone are preferred, and N-methyl-2-pyrrolidone is more preferred.

Moreover, even if it is a solvent which does not dissolve a polyamic acid independently, it can use for preparation of a composition as long as it is a range in which a polyamic acid does not precipitate. In particular, 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, A solvent having a low surface tension such as dipropylene glycol, 2-(2-ethoxypropoxy)propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, etc. can be properly mixed. . It is known that this improves the uniformity of the coating film at the time of application to the substrate, and can be suitably used in the present invention as well.

The method for preparing the composition for forming a protective layer for a substrate of the present invention is arbitrary. A preferable example of the preparation method is a method of filtering a reaction solution containing the target polyamic acid obtained by the method described above. At this time, if it is necessary to adjust the concentration or the like, the filtrate may be diluted or concentrated. By employing such a method, it is possible to not only reduce the incorporation of impurities that may cause deterioration of adhesion, peelability, etc. of the substrate protective layer produced from the composition obtained, but also to efficiently obtain a composition for forming a substrate protective layer. can The solvent used for dilution is not particularly limited, and specific examples thereof include the same as the specific examples of the reaction solvent in the above reaction. The solvent used for dilution can be used individually by 1 type or in combination of 2 or more types.

The concentration of the polyamic acid in the composition for forming a substrate protective layer of the present invention is appropriately set in consideration of the thickness of the substrate protective layer to be produced, the viscosity of the composition, etc. It is about 20% by mass. By setting such a concentration, a substrate protective layer having a thickness of about 0.05 to 5 μm can be obtained with good reproducibility. The concentration of the polyamic acid can be adjusted by adjusting the amounts used of diamine and tetracarboxylic dianhydride, which are raw materials of the polyamic acid, or by adjusting the amounts when the isolated polyamic acid is dissolved in a solvent.

The viscosity of the composition for forming a substrate protective layer of the present invention is appropriately set in consideration of the thickness of the substrate protective layer to be produced. In particular, when the purpose is to obtain a film having a thickness of about 0.05 to 5 μm with good reproducibility, it is usually 25 ° C. is about 10 to 10,000 mPa·s, preferably about 20 to 5,000 mPa·s.

Here, the viscosity can be measured using a commercially available viscometer for measuring the viscosity of liquids, for example, by referring to the procedures described in JIS K7117-2, under conditions of a composition temperature of 25°C. Preferably, a conical plate type (cone plate type) rotational viscometer is used as the viscometer, and preferably a viscometer of the same type is used as a standard cone rotor and 1° 34'×R24 is used to measure the composition under the condition of a temperature of 25°C. can As such a rotational viscometer, Toki Sangyo Co., Ltd. TVE-25L is mentioned, for example.

In addition to the polyamic acid and the organic solvent, the composition for forming a substrate protective layer of the present invention may also contain, for example, a crosslinking agent to improve film strength.

After applying the above-described composition for forming a release layer on a substrate, the polyamic acid is thermally imidized by a firing method including a step of firing at a maximum temperature of 500 ° C. or higher, thereby providing easy release from the substrate and good adhesion to the resin substrate. A resin substrate protective layer made of a polyimide film having excellent adhesion can be obtained.

In the present invention, the maximum temperature during the firing is not particularly limited as long as it is within a range of 500°C or higher and lower than or equal to the heat resistance temperature of polyimide. The upper limit is usually about 550°C, preferably about 520°C, and more preferably about 510°C. By setting the heating temperature within the above range, it is also possible to sufficiently advance the imidation reaction while preventing embrittlement of the obtained film.

Since the heating time differs depending on the heating temperature, it cannot be defined collectively, but it is usually 5 minutes to 5 hours. In addition, the imidation ratio may be in the range of 50 to 100%.

Further, the temperature at the time of the firing may include a step of firing at a temperature lower than the maximum temperature as long as the maximum temperature is within the above range.

As a preferred example of the heating mode in the present invention, a method of heating at 50 to 150°C, then raising the heating temperature step by step as it is, and finally heating at 500°C or higher is exemplified. In particular, as a more preferable example of the heating mode, a method of heating at 50 to 100°C, heating at more than 100°C to less than 500°C, and heating at 500°C or higher is exemplified. Another more preferable example of the heating mode is a method of heating at 50 to 100 ° C, followed by heating at 200 to 300 ° C, heating at more than 300 ° C to less than 500 ° C, and finally heating at 500 to 510 ° C. .

In addition, as a preferable example of the heating mode in the case of considering the firing time, a method of heating at 50 to 150 ° C. for 1 minute to 2 hours, then raising the heating temperature step by step as it is, and finally heating at 500 ° C. or higher for 30 minutes to 4 hours is given. can In particular, as a more preferable example of the heating mode, a method of heating at 50 to 100°C for 1 minute to 2 hours, heating at more than 100°C to less than 500°C for 5 minutes to 2 hours, and heating at 500°C or higher for 30 minutes to 4 hours. can be heard Another more preferable example of the heating mode is heating at 50 to 100 ° C for 1 minute to 2 hours, then at 200 to 300 ° C for 5 minutes to 2 hours, above 300 ° C to less than 500 ° C for 5 minutes to 2 hours, and finally at 500 ° C. A method of heating at ~510°C for 1 minute to 2 hours is exemplified.

When such a substrate protective layer of the present invention is formed on a substrate, the substrate protective layer may be formed on a part of the surface of the substrate or may be formed on the entire surface of the substrate. As an aspect of forming a substrate protective layer on a part of the surface of the substrate, an aspect of forming the substrate protective layer only in a predetermined range on the surface of the substrate, forming a substrate protective layer in a pattern such as a dot pattern or a line and space pattern on the entire surface of the substrate There are suns that do. Also, in the present invention, the base means that the composition for forming a substrate protective layer of the present invention is painted on its surface, and is used for manufacturing flexible electronic devices and the like.

As the substrate (base material), for example, glass, plastic (polycarbonate, polymethacrylate, polystyrene, polyester, polyolefin, epoxy, melamine, triacetyl cellulose, ABS, AS, norbornene-based resin, etc.), metal (silicon wafer) etc.), wood, paper, slate, etc., but glass is particularly preferable in that the substrate protective layer of the present invention has sufficient adhesion thereto. In addition, the substrate surface may be composed of a single material or may be composed of two or more materials. As an aspect in which the surface of the aircraft is composed of two or more materials, a certain range of the surface of the aircraft is composed of a certain material and the rest of the surface is composed of other materials, a pattern such as a dot pattern and a line and space pattern over the entire surface of the aircraft In terms of shape, there is an aspect in which a certain material exists among other materials.

The method of applying the composition for forming a substrate protective layer of the present invention to a substrate is not particularly limited, but examples include a cast coat method, a spin coat method, a blade coat method, a dip coat method, a roll coat method, a bar coat method, and a die coat method. Coating method, inkjet method, printing method (iron plate, intaglio, flat plate, screen printing, etc.), etc. are mentioned.

As for the apparatus used for heating, a hot plate, an oven, etc. are mentioned, for example. The heating atmosphere may be air or an inert gas, and may be normal pressure or reduced pressure.

The thickness of the substrate protective layer is usually about 0.01 to 50 μm, and preferably about 0.05 to 20 μm from the viewpoint of productivity. Also, a desired thickness is realized by adjusting the thickness of the coating film before heating.

The substrate protective layer described above has appropriate adhesion to a substrate, particularly glass substrate, appropriate peelability, and excellent adhesion to a resin substrate. Therefore, the substrate protective layer of the present invention can be suitably used in the manufacturing process of a flexible electronic device to separate the resin substrate from a substrate together with a circuit or the like formed on the resin substrate without damaging the resin substrate of the device. can

The resin substrate formed on the substrate protective layer is not particularly limited, but from the viewpoint of heat resistance, it is preferable that the 1% weight reduction temperature in thermogravimetric analysis is 500°C or higher.

As such a resin substrate, a resin substrate using a wholly aromatic polymer such as a wholly aromatic polyimide, polybenzoxazole, polybenzothiazole, or polybenzoimidazole is exemplified. Moreover, a hybrid film in which silica sol, titania sol, or the like is added to the polymer may be used.

Hereinafter, an example of a method for manufacturing a flexible electronic device using the substrate protective layer of the present invention will be described.

A substrate protective layer is formed on a glass substrate by the method described above using the composition for forming a substrate protective layer of the present invention. A resin substrate forming solution for forming a resin substrate is applied onto this substrate protective layer, and the coating film is fired to form a resin substrate fixed to the glass substrate through the substrate protective layer of the present invention.

The firing temperature of the coating film is appropriately set depending on the type of resin and the like, but in the present invention, it is preferable to set the maximum temperature during firing to 500°C or higher. The upper limit is usually about 550°C, but preferably about 520°C and more preferably about 510°C.

By making the maximum temperature during firing during fabrication of the resin substrate within this range, the peelability between the protective layer serving as the substrate and the substrate, and the appropriate adhesiveness and peelability between the substrate protective layer and the resin substrate can be further improved.

Also in this case, as long as the maximum temperature is within the above range, a step of firing at a temperature lower than that may be included.

As a preferred example of the heating mode in the production of the resin substrate, a method of heating at 50 to 150°C, then raising the heating temperature step by step as it is, and finally heating at 500°C or higher is exemplified. In particular, as a more preferable example of the heating mode, a method of heating at 50 to 100°C, heating at more than 100°C to less than 500°C, and heating at 500°C or higher is exemplified. Further, as another more preferable example of the heating mode, after heating at 50 to 100 ° C, heating at more than 100 ° C to 200 ° C, heating at more than 200 ° C to 300 ° C, heating at more than 300 ° C to less than 500 ° C, and finally The method of heating at 500-510 degreeC is mentioned.

In addition, as a preferable example of the heating mode in the case of considering the firing time, a method of heating at 50 to 150 ° C. for 1 minute to 2 hours, then raising the heating temperature step by step as it is, and finally heating at 500 ° C. or higher for 30 minutes to 4 hours is given. can In particular, as a more preferable example of the heating mode, a method of heating at 50 to 100°C for 1 minute to 2 hours, heating at more than 100°C to less than 500°C for 5 minutes to 2 hours, and heating at 500°C or higher for 30 minutes to 4 hours. can be heard Another more preferable example of the heating mode is heating at 50 to 100 ° C for 1 minute to 2 hours, then over 100 ° C to 200 ° C for 5 minutes to 2 hours, over 200 ° C to 300 ° C for 5 minutes to 2 hours, 300 ° C A method of heating at more than 500°C for 5 minutes to 2 hours and finally at 500 to 510°C for 30 minutes to 4 hours is exemplified.

Next, a desired circuit is formed on the resin substrate fixed to the substrate through the substrate protective layer of the present invention, and then the resin substrate is cut along the substrate protective layer, for example, and the resin substrate together with the circuit. and separating the substrate protective layer from the substrate to separate the resin substrate and the substrate protective layer from the substrate. At this time, a part of the substrate may be cut together with the substrate protective layer.

Further, in Japanese Patent Laid-Open No. 2013-147599, it is reported that the laser lift-off method (LLO method), which has been used in the manufacture of high-brightness LEDs, three-dimensional semiconductor packages, etc., is applied to the manufacture of flexible displays. The LLO method is characterized in that a light ray of a specific wavelength, for example, a light ray having a wavelength of 308 nm is irradiated from the side of the glass substrate from the surface opposite to the surface on which the circuit or the like is formed. The irradiated light beam passes through the glass substrate, and only the polymer (polyimide) in the vicinity of the glass substrate absorbs this light beam and evaporates (sublimes). As a result, it becomes possible to selectively peel the substrate protective layer from the glass substrate without affecting the circuitry installed on the resin substrate that determines the performance of the display.

Since the composition for forming a substrate protective layer of the present invention has a feature of sufficiently absorbing light rays of a specific wavelength (for example, 308 nm) to which the LLO method can be applied, it can be used as a sacrificial layer for the LLO method. For this reason, a desired circuit is formed on a resin substrate fixed to a glass substrate through a substrate protective layer formed using the composition of the present invention, and then the LLO method is performed to irradiate the substrate with a 308 nm light beam. Only the protective layer absorbs this light and evaporates (sublimes). This makes it possible to selectively separate the resin substrate from the glass base by sacrificing the substrate protective layer (acting as a sacrificial layer).

(Example)

Hereinafter, the present invention will be described in more detail with examples, but the present invention is not limited to these examples.

[1] Abbreviations of compounds

p-PDA: p-phenylenediamine

TFMB: 2,2'-bis(trifluoromethyl)benzidine

BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride

PMDA: pyromellitic dianhydride

CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride

NMP: N-methyl-2-pyrrolidone

BCS: butyl cellosolve

PGME: Propylene glycol monomethyl ether

[2] Method for measuring weight average molecular weight and molecular weight distribution

Measurement of the weight average molecular weight (hereinafter abbreviated to Mw) and molecular weight distribution of the polymer was performed using a GPC device manufactured by Nippon Bunko Co., Ltd. (Column: KD801 and KD805 manufactured by Shodex; eluent: dimethylformamide/LiBr H ₂ O (29.6 mM)/ H ₃ PO ₄ (29.6 mM)/THF (0.1 wt%); flow rate: 1.0 mL/min; column temperature: 40°C; Mw: standard polystyrene equivalent).

[3] Synthesis of polymers

A polyamic acid was synthesized by the following method.

Further, a composition for forming a resin substrate or a composition for forming a substrate protective layer was prepared by diluting the reaction liquid as described later without isolating the polymer from the resulting polymer-containing reaction liquid.

<Synthesis Example S1 Synthesis of polyamic acid (S1)>

After dissolving 3.176 g (0.02937 mol) of p-PDA in 88.2 g of NMP and adding 8.624 g (0.02931 mol) of BPDA, the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere. Mw of the obtained polymer was 107,300 and molecular weight distribution 4.6.

<Synthesis Example L1 Synthesis of polyamic acid (L1)>

23.7 g (74.2 mmol) of TFMB was dissolved in 352 g of NMP. BPDA 24.2g (82.5mmol) was added to the obtained solution, and it was made to react at 23 degreeC for 24 hours in nitrogen atmosphere. Mw of the obtained polymer was 76,400 and molecular weight distribution 2.2. The obtained solution was soluble in PGME.

<Synthesis Example L2 Synthesis of polyamic acid (L2)>

9.89 g (30.9 mmol) of TFMB was dissolved in 380 g of PGME. BPDA 10.0g (34.3mmol) was added to the obtained solution, and it was made to react at 50 degreeC for 72 hours in nitrogen atmosphere. Mw of the obtained polymer was 76,400 and molecular weight distribution 2.2.

<Comparative Synthesis Example HL1 Synthesis of polyamic acid (HL1)>

2.73 g (8.53 mmol) of TFMB was dissolved in 38.5 g of NMP. PMDA 2.06g (9.47mmol) was added to the obtained solution, and it was made to react at 23 degreeC in nitrogen atmosphere for 24 hours. Mw of the obtained polymer was 76,400 and molecular weight distribution 2.2. The obtained solution was soluble in PGME.

<Comparative Synthesis Example HL2 Synthesis of polyamic acid (HL2)>

2.86 g (8.91 mmol) of TFMB was dissolved in 35.2 g of NMP. CBDA 1.94g (9.91mmol) was added to the obtained solution, and it was made to react at 23 degreeC for 24 hours in nitrogen atmosphere. Mw of the obtained polymer was 69,200 and molecular weight distribution 2.2. The obtained solution was soluble in PGME.

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

[Preparation Example 1]

The reaction solution obtained in Synthesis Example S1 was used as it was as a composition for forming a resin substrate.

[5] Preparation of a composition for forming a substrate protective layer

[Example 1-1]

BCS and NMP were added to the reaction solution obtained in Synthesis Example L1 and diluted so that the polymer concentration was 5 wt% and the BCS was 20 mass%, thereby obtaining a composition for forming a substrate protective layer.

[Example 1-2]

The reaction solution obtained in Synthesis Example L2 was used as a composition for forming a substrate protective layer as it was.

[Comparative Example 1-1]

BCS and NMP were added to the reaction solution obtained in Comparative Synthesis Example HL1 and diluted so that the polymer concentration was 5 wt% and the BCS was 20 mass%, thereby obtaining a composition for forming a substrate protective layer.

[Comparative Example 1-2]

BCS and NMP were added to the reaction solution obtained in Comparative Synthesis Example HL2 and diluted so that the polymer concentration was 5 wt% and the BCS was 20 mass%, thereby obtaining a composition for forming a substrate protective layer.

[6] Production of substrate protective layer and resin substrate

[Example 2-1]

The composition for forming a substrate protective layer obtained in Example 1-1 was applied onto a 100 mm x 100 mm glass substrate (the same below) as a glass substrate using a spin coater (condition: rotation speed of 3,000 rpm for about 30 seconds).

And the obtained coating film was heated at 80 ° C. for 10 minutes using a hot plate, then heated at 300 ° C. for 30 minutes and at 400 ° C. for 30 minutes using an oven, and then further heated at 500 ° C. for 10 minutes, A substrate protective layer having a thickness of about 0.1 μm was formed on the substrate to obtain a glass substrate with a substrate protective layer. In addition, the heating rate between each heating temperature was 5°C/min, and while the temperature was being raised, the film-attached substrate was heated in the oven without taking it out of the oven.

The composition for forming a resin substrate was applied onto the substrate protective layer (resin thin film) on the glass substrate obtained above using a bar coater (gap: 250 μm). Then, the obtained coating film was heated at 80°C for 40 minutes using a hot plate, then heated at 140°C, 210°C, 300°C, and 400°C for 30 minutes using an oven, and then further heated at 500°C for 60 minutes. After heating for a minute, a polyimide resin substrate having a thickness of about 10 μm was formed on the substrate protective layer, and a resin substrate/glass substrate with a substrate protective layer was obtained. In addition, the heating rate between each heating temperature was 2°C/min, and while the temperature was being raised, the film-attached substrate was heated in the oven without taking it out of the oven.

[Example 2-2]

A substrate protective layer and a polyimide resin substrate were prepared in the same manner as in Example 2-1, except that the composition for forming a protective layer obtained in Example 1-2 was used instead of the composition for forming a protective layer obtained in Example 1-1. was formed to obtain a glass substrate with a substrate protective layer and a glass substrate with a resin substrate/substrate protective layer.

[Comparative Examples 2-1 to 2-2]

Substrate protective layer in the same manner as in Example 2-1, except that the composition for forming a protective layer obtained in Comparative Examples 1-1 to 1-2 was used instead of the composition for forming a protective layer obtained in Example 1-1. And a polyimide resin substrate was formed to obtain a glass substrate with a substrate protective layer and a glass substrate with a resin substrate/substrate protective layer.

[7] Evaluation of peelability

The resin substrate and the substrate protective layer of the glass substrate with the resin substrate and substrate protective layer obtained in Examples 2-1 to 2-2 and Comparative Examples 2-1 to 2-2 were cut into a strip shape with a width of 2 cm and a length of 5 cm using a cutter. cut with And the adhesive tape was affixed to the edge part of the cut resin substrate, and this was made into the test piece. This test piece was subjected to a peeling test so that the peeling angle was 170° using a push-pull tester manufactured by Atonic Co., Ltd., and the peelability was evaluated based on the following criteria. The results are shown in Table 1.

<Criteria for Evaluation of Peelability of Glass Substrate and Substrate Protective Layer>

○: The substrate protective layer is all peeled off from the glass substrate.

Δ: The resin substrate can be peeled off, but the substrate protective layer remains on a part of the glass substrate.

x: The resin substrate and the substrate protective layer cannot be separated from the glass substrate.

In addition, the surface of the glass surface at the peeled site was scraped off with a cutter, and film remaining properties were evaluated based on the following criteria. The results are shown in Table 1.

<Criteria for Evaluation of Residual Film Property of Substrate Protective Layer on Glass Substrate>

○: There is no residual film of the substrate protective layer.

Δ: A part of the substrate protective layer remains.

x: The substrate protective layer remains.

-: Evaluation is impossible because the resin substrate is not peeled off.

substrate protective layer Peelability between glass substrate and substrate protective layer Film retention of the substrate protective layer on the glass substrate Example 2-1 L1 ○ ○ Example 2-2 L2 ○ ○ Comparative Example 2-1 HL1 × - Comparative Example 2-2 HL2 × -

As shown in Table 1, it was confirmed that the substrate protective layers of Examples 2-1 to 2-2 were easily peeled off together with the resin substrate, and there was no residual film of the substrate protective layer on the glass substrate. On the other hand, the resin substrates of Comparative Examples 2-1 to 2-2 were firmly adhered to the glass substrate with the substrate protective layer interposed therebetween, and could not be peeled off from the glass substrate.

[9] Properties of resin film

The mechanical properties of the resin substrate obtained in Example 2-1 were measured. Further, as a comparison, a resin substrate prepared by directly applying and firing composition S1 for forming a resin substrate on a substrate without forming a substrate protective layer was used. At that time, the substrate was changed from the glass substrate to the silicon substrate, and a resin substrate was formed in the same manner as in Example 2-1 except for that. The obtained resin film was made into SF1.

<Coefficient of linear expansion>

A strip-shaped test piece of 20 mm × 5 mm was prepared from the film obtained above, and the coefficient of linear expansion from 50 ° C. to 500 ° C. was measured using TMA-4000SA (manufactured by Bruker AXS Co., Ltd.). The results are shown in Table 2.

<weight reduction>

A strip-shaped test piece of 20 mm × 3 mm was prepared from the film obtained above, and the weight loss from 50 ° C. to 600 ° C. , the temperature at which a weight loss of 1% was found. The results are shown in Table 2.

substrate protective layer coefficient of linear expansion
(ppm/℃) 1% weight reduction
(℃) SF1 - -15 550 Example 2-1 L1 -9 548

As shown in Table 2, it was confirmed that there was no difference in mechanical properties between the resin substrate with a substrate protective layer produced in Examples and the resin substrate produced without forming a substrate protective layer. From the above results, it was confirmed that the substrate protective layer did not affect the mechanical properties of the fabricated resin substrate.

Claims (11)

A composition for forming a substrate protective layer containing a polyamic acid represented by the following formula (1) and an organic solvent is applied onto a substrate, and fired at a maximum temperature of 500° C. or higher to obtain a substrate protective layer having easy releasability from the substrate. forming process,
A step of applying a composition for forming a resin substrate on the substrate protective layer and firing it at a maximum temperature of 500° C. or higher to form a resin substrate;
A step of manufacturing an electronic device on the resin substrate;
and a step of peeling the electronic device together with the substrate protective layer and the resin substrate from the substrate.

(In the formula, X represents an aromatic group represented by the following formula (2), Y represents a divalent aromatic group having a fluorine atom, and n represents a natural number.)

The method of manufacturing a flexible electronic device according to claim 1, wherein Y is an aromatic group represented by the following formula (3).

The method of manufacturing a flexible electronic device according to claim 1, wherein Y is an aromatic group represented by the following formula (4).

The method for manufacturing a flexible electronic device according to claim 1, wherein the organic solvent is at least one selected from those having structures represented by the following formulas (S1) to (S7).

(Wherein, R ¹ to R ⁸ independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ⁹ and R ¹⁰ are independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms) represents an acyl group of, and b and n represent natural numbers) The method for manufacturing a flexible electronic device according to any one of claims 1 to 4, wherein the resin substrate is a polyimide resin substrate. A composition for forming a substrate protective layer containing a polyamic acid represented by the following formula (1) and an organic solvent is applied onto a substrate, fired at a maximum temperature of 500° C. or higher to form a substrate protective layer, and then the substrate protective layer is formed. A composition for forming a resin substrate is applied to a substrate, fired at a maximum temperature of 500° C. or higher to form a resin substrate, and then the resin substrate together with the substrate protective layer is separated from the substrate. method.

(In the formula, X represents an aromatic group represented by the following formula (2), Y represents a divalent aromatic group having a fluorine atom, and n represents a natural number.)

The method for manufacturing a resin substrate with a protective layer according to claim 6, wherein Y is an aromatic group represented by the following formula (3).

The method for manufacturing a resin substrate with a protective layer according to claim 6, wherein Y is an aromatic group represented by the following formula (4).

The method for manufacturing a resin substrate with a protective layer according to claim 6, wherein the organic solvent is at least one selected from those having structures represented by the following formulas (S1) to (S7).

(Wherein, R ¹ to R ⁸ independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ⁹ and R ¹⁰ are independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms) represents an acyl group of, and b and n represent natural numbers) The method for manufacturing a resin substrate with a protective layer according to any one of claims 6 to 9, wherein the resin substrate is a polyimide resin substrate. delete