JP6729403B2 - Composition for forming release layer - Google Patents

Description

The present invention relates to a release layer-forming composition, and more specifically to a release layer-forming composition for forming a release layer provided on a substrate.

2. Description of the Related Art In recent years, electronic devices have been required to have a function of being bent and to be thin and lightweight. For this reason, it is required to use a lightweight flexible plastic substrate in place of the conventional glass substrate which is heavy and fragile and cannot be bent. Further, in the new generation display, development of an active full-color TFT display panel using a lightweight flexible plastic substrate is required. Therefore, various methods for manufacturing an electronic device using a resin film as a substrate have begun to be studied, and for a new-generation display, the manufacturing study is being carried out by a process in which existing TFT equipment can be used.

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 surface side to crystallize the amorphous silicon. A method for peeling a plastic substrate from a glass substrate by using generated hydrogen gas is disclosed. Further, Patent Document 4 uses a technique disclosed in Patent Documents 1 to 3 to attach a layer to be peeled (described as “transferred layer” in Patent Document 4) to a plastic film to complete a liquid crystal display device. A method is disclosed.

However, in the methods disclosed in Patent Documents 1 to 4, particularly the method disclosed in Patent Document 4, it is essential to use a substrate having a high light-transmitting property. Since a sufficient amount of energy is released to release the contained hydrogen, relatively large laser light irradiation is required, which causes a problem of damaging the layer to be peeled. In addition, laser processing requires a long time, and it is difficult to peel off a layer to be peeled, which has a large area, which makes it difficult to increase productivity in device manufacturing.

JP, 10-125929, A JP, 10-125931, A International Publication No. 2005/050754 JP, 10-125930, A

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a release layer-forming composition that can be released without damaging a resin substrate of a flexible electronic device.

The present inventors have conducted extensive studies to solve the above problems, a polyamic acid obtained by reacting an aromatic diamine and an aromatic tetracarboxylic dianhydride, and a composition containing an organic solvent, The aromatic diamine contains an aromatic diamine containing at least one of an ester bond and an ether bond, and/or the aromatic tetracarboxylic dianhydride contains an aromatic bond containing at least one of an ester bond and an ether bond. When containing an anhydride, it is possible to obtain a composition capable of forming a release layer having excellent adhesion to a substrate, and suitable adhesion to a resin substrate used as a flexible electronic device and suitable release properties. Heading, completed the present invention.

２． 前記芳香族テトラカルボン酸二無水物が、更にエステル結合及びエーテル結合のいずれも含まない芳香族テトラカルボン酸二無水物を含む１の剥離層形成用組成物、
３． 前記エステル結合及びエーテル結合のいずれも含まない芳香族テトラカルボン酸二無水物が、ベンゼン骨格、ナフチル骨格又はビフェニル骨格を含むものである２の剥離層形成用組成物、
４． 前記エステル結合及びエーテル結合のいずれも含まない芳香族テトラカルボン酸二無水物が、式（Ｃ１）〜（Ｃ１２）からなる群から選ばれる少なくとも１種である３の剥離層形成用組成物、

５． 前記有機溶媒が、式（Ｓ１）で表されるアミド類、式（Ｓ２）で表されるアミド類及び式（Ｓ３）で表されるアミド類から選ばれる少なくとも１つを含む１〜４のいずれかの剥離層形成用組成物、

（式中、Ｒ¹及びＲ²は、互いに独立して、炭素数１〜１０のアルキル基を表す。Ｒ³は、水素原子、又は炭素数１〜１０のアルキル基を表す。ｈは、自然数を表す。）
６． １〜５のいずれかの剥離層形成用組成物を用いて形成される剥離層、
７． ６の剥離層を用いることを特徴とする、樹脂基板を備えるフレキシブル電子デバイスの製造方法、
８． ６の剥離層を用いることを特徴とする、樹脂基板を備えるタッチパネルセンサーの製造方法、
９． 前記樹脂基板が、ポリイミドからなる基板である７又は８の製造方法
を提供する。
That is, the present invention is
1. A polyamic acid obtained by reacting an aromatic diamine and an aromatic tetracarboxylic dianhydride, and an organic solvent,
The aromatic diamine includes an aromatic diamine containing an ester bond which is at least one selected from the group consisting of formulas (A4) to (A6), (A13) to (A24) and (A34) to (A39). And/or the aromatic tetracarboxylic dianhydride contains an ester bond which is at least one selected from the group consisting of formulas (B1), (B2), (B5) to (B7) and (B11). A composition for forming a peeling layer, which comprises an aromatic tetracarboxylic dianhydride,

2 . The aromatic tetracarboxylic acid dianhydride, further an ester bond and 1 of the release layer forming composition comprising an aromatic tetracarboxylic acid dianhydride containing neither ether bond,
3 . The composition for forming a peeling layer of 2 , wherein the aromatic tetracarboxylic dianhydride containing neither an ester bond nor an ether bond contains a benzene skeleton, a naphthyl skeleton or a biphenyl skeleton.
4 . The composition for forming a peeling layer of 3 , wherein the aromatic tetracarboxylic dianhydride containing neither ester bond nor ether bond is at least one selected from the group consisting of formulas (C1) to (C12),

5 . Any of 1 to 4 , wherein the organic solvent contains at least one selected from amides represented by formula (S1), amides represented by formula (S2) and amides represented by formula (S3). A composition for forming a release layer,

(In the formula, R ¹ and R ² independently represent an alkyl group having 1 to 10 carbon atoms. R ³ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. h is a natural number. Represents.)
6 . A release layer formed using the release layer-forming composition according to any one of 1 to 5 ;
7 . 6. A method of manufacturing a flexible electronic device including a resin substrate, characterized in that the release layer of 6 is used.
8 . 6. A method for manufacturing a touch panel sensor including a resin substrate, characterized in that the release layer of 6 is used,
9 . There is provided the method 7 or 8 , wherein the resin substrate is a substrate made of polyimide.

By using the composition for forming a release layer of the present invention, a film having excellent adhesion to a substrate, appropriate adhesion to a resin substrate, and appropriate releasability can be obtained with good reproducibility. By using the composition of the present invention, in the process of manufacturing a flexible electronic device, the resin substrate formed on the substrate and the circuit provided on the resin substrate are not damaged, and the resin substrate is provided together with the circuit. Can be separated from the substrate. Therefore, the composition for forming a release layer of the present invention can contribute to simplification of the manufacturing process of a flexible electronic device including a resin substrate, improvement of its yield, and the like.

9 is a graph showing the transmittance measured in Example 4.

Hereinafter, the present invention will be described in more detail.
The release layer-forming composition of the present invention contains a polyamic acid obtained by reacting an aromatic diamine and an aromatic tetracarboxylic dianhydride, and an organic solvent, wherein the aromatic diamine is an ester. It contains an aromatic diamine containing at least one of a bond and an ether bond, and/or the aromatic tetracarboxylic acid dianhydride contains an aromatic tetracarboxylic acid dianhydride containing at least one of an ester bond and an ether bond. .. Here, the release layer in the present invention is a layer provided directly on the glass substrate for a predetermined purpose, and a typical example thereof is a flexible electronic device made of a resin such as polyimide in the manufacturing process of a flexible electronic device. It is provided to fix the resin substrate to the resin substrate of the device during a predetermined process, and the resin substrate is easily peeled from the substrate after the electronic circuit and the like are formed on the resin substrate. The thing provided to enable it is mentioned.

The aromatic diamine containing at least one of an ester bond and an ether bond has either an ester bond or an ether bond in the molecule, or both of them.

Examples of such aromatic diamines include diamines having a structure in which a plurality of aromatic rings having 6 to 20 carbon atoms are linked by an ester bond or an ether bond. Specific examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring. Above all, diamine having a structure in which two or three aromatic rings are linked by an ester bond or an ether bond is preferable from the viewpoint of ensuring the solubility of the polyamic acid in the organic solvent.

In the present invention, preferred specific examples of the aromatic diamine containing at least one of an ester bond and an ether bond include those shown below.

The aromatic tetracarboxylic acid dianhydride containing at least one of the ester bond and the ether bond has either an ester bond or an ether bond in the molecule, or both of them.

Examples of such an aromatic tetracarboxylic dianhydride include a tetracarboxylic dianhydride having a structure in which a plurality of aromatic rings having 6 to 20 carbon atoms are linked by an ester bond or an ether bond. Specific examples of the aromatic ring include the same ones as described above. Among them, those having a structure in which 3 or 4 aromatic rings are linked by an ester bond or an ether bond are preferable from the viewpoint of ensuring the solubility of the polyamic acid in an organic solvent.

In the present invention, preferred specific examples of the aromatic tetracarboxylic dianhydride containing at least one of an ester bond and an ether bond include those shown below.

In the present invention, other diamines can be used together with the aromatic diamine containing at least one of the ester bond and the ether bond described above.

Such diamine may be either an aliphatic diamine or an aromatic diamine, but from the viewpoint of ensuring the strength and heat resistance of the obtained thin film, an aromatic diamine containing neither an ester bond nor an ether bond is preferable.

Specific examples thereof include 1,4-diaminobenzene (p-phenylenediamine), 1,3-diaminobenzene (m-phenylenediamine), 1,2-diaminobenzene (o-phenylenediamine) and 2,4-diamino. Toluene, 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-xylylenediamine, 5-trifluoromethylbenzene-1 ,3-diamine, 5-trifluoromethylbenzene-1,2-diamine, diamine containing one benzene nucleus such as 3,5-bis(trifluoromethyl)benzene-1,2-diamine; 1,2-naphthalene Diamine, 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, 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'-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, 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'-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, diamine containing two benzene nuclei such as 4,4'-diaminooctafluorobiphenyl; 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-aminophenyl sulfide)benzene, 1,3-bis(3-aminophenyl sulfone)benzene, 1,3-bis(4-aminophenyl sulfone)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 Examples thereof include, but are not limited to, a diamine containing three benzene nuclei such as -(4-aminophenyl)isopropyl]benzene. These may be used alone or in combination of two or more.

In the present invention, together with an aromatic diamine containing at least one of an ester bond and an ether bond, when using a diamine other than that, the amount of the aromatic diamine containing at least one of an ester bond and an ether bond is preferably all diamines. Is 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and further preferably 95 mol% or more. By adopting such an amount used, it is possible to obtain a film having excellent adhesion to the substrate, appropriate adhesion to the resin substrate, and appropriate releasability with good reproducibility.

In the present invention, the above-mentioned aromatic tetracarboxylic dianhydride containing at least one of an ester bond and an ether bond can be used together with other tetracarboxylic dianhydrides.

Such a tetracarboxylic dianhydride may be either an aliphatic tetracarboxylic dianhydride or an aromatic tetracarboxylic dianhydride, but from the viewpoint of securing the strength and heat resistance of the obtained thin film, an ester bond And aromatic tetracarboxylic dianhydrides containing neither ether bond nor ether bond are preferred.

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 acid dianhydride, naphthalene-1,2,6,7-tetracarboxylic acid dianhydride, naphthalene-1,2,7,8-tetracarboxylic acid dianhydride, naphthalene- 2,3,5,6-tetracarboxylic dianhydride, naphthalene-2,3,6,7-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, biphenyl -2,2',3,3'-tetracarboxylic dianhydride, biphenyl-2,3,3',4'-tetracarboxylic dianhydride, biphenyl-3,3',4,4'-tetra Carboxylic dianhydride, Anthracene-1,2,3,4-tetracarboxylic dianhydride, Anthracene-1,2,5,6-tetracarboxylic dianhydride, Anthracene-1,2,6,7- Tetracarboxylic acid dianhydride, Anthracene-1,2,7,8-tetracarboxylic acid dianhydride, Anthracene-2,3,6,7-tetracarboxylic acid 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 acid dianhydride, Phenanthrene-1,2,9,10-tetracarboxylic acid dianhydride, Phenanthrene-2,3,5,6-tetracarboxylic acid dianhydride, Phenanthrene-2,3,6 ,7-Tetracarboxylic acid dianhydride, Phenanthrene-2,3,9,10-tetracarboxylic acid dianhydride, Phenanthrene-3,4,5,6-tetracarboxylic acid dianhydride, Phenanthrene-3,4, Examples thereof include, but are not limited to, 9,10-tetracarboxylic dianhydride. These may be used alone or in combination of two or more.

In particular, as the aromatic tetracarboxylic dianhydride containing neither an ester bond nor an ether bond, at least one selected from the group consisting of formulas (C1) to (C12) is preferable from the viewpoint of ensuring heat resistance. More preferably, at least one selected from the group consisting of formula (C1) and formula (C9).

In the present invention, together with an aromatic tetracarboxylic dianhydride containing at least one of an ester bond and an ether bond, when using other tetracarboxylic acid dianhydride, an aromatic tetracarboxylic acid containing at least one of an ester bond and an ether bond. The amount of the carboxylic dianhydride used is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, further preferably 95 mol% or more, based on the total tetracarboxylic dianhydride. Is. By adopting such an amount used, it is possible to reproducibly obtain a film having sufficient adhesion to the substrate, appropriate adhesion to the resin substrate, and appropriate releasability.

The polyamic acid contained in the release layer-forming composition according to the present invention can be obtained by reacting the above-described diamine with tetracarboxylic dianhydride.

The organic solvent used in such a reaction is not particularly limited as long as it does not adversely affect the reaction, but 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 Examples include -tert-butoxy-N,N-dimethylpropylamide and γ-butyrolactone. In addition, you may use an organic solvent individually by 1 type or in combination of 2 or more types.

In particular, since the organic solvent used in the reaction dissolves diamine, tetracarboxylic dianhydride, and polyamic acid well, the amides represented by formula (S1), the amides represented by (S2) and the formula (S2) At least one selected from the amides represented by S3) is preferable.

In the formula, R ¹ and R ² each independently represent an alkyl group having 1 to 10 carbon atoms. R ³ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. h represents a natural number, but is preferably 1 to 3, and 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-heptyl group, n-octyl group, n-nonyl group, n-decyl group and the like can be mentioned. Of 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.

The reaction temperature may be appropriately set in the range from the melting point to the boiling point of the solvent used, and is usually about 0 to 100° C., but it prevents imidization of the resulting polyamic acid in a solution and thus has a high content of polyamic acid units. In order to maintain the amount, it is preferably about 0 to 70°C, more preferably about 0 to 60°C, and even more preferably about 0 to 50°C.

The reaction time cannot be specified unconditionally because it depends on the reaction temperature and the reactivity of the raw material, but it is usually about 1 to 100 hours.

By the method described above, a reaction solution containing the target polyamic acid can be obtained.

The weight average molecular weight of the polyamic acid is preferably 5,000 to 1,000,000, more preferably 10,000 to 500,000, and even more preferably 15,000 to 200,000 from the viewpoint of handleability. In the present invention, the weight average molecular weight is an average molecular weight obtained by gel permeation chromatography (GPC) analysis in terms of standard polystyrene.

In the present invention, usually, the reaction solution is filtered, and then the filtrate is used as it is, or a solution obtained by diluting or concentrating it can be used as the composition for forming a release layer of the present invention. By doing so, it is possible not only to reduce the mixture of impurities that may cause the deterioration of the adhesiveness and the releasability of the obtained release layer, but also to obtain the release layer forming composition efficiently. In addition, after separating the polyamic acid from the reaction solution, it may be dissolved again in a solvent to obtain a release layer forming composition. Examples of the solvent in this case include the organic solvents used in the above-mentioned reaction.

The solvent used for dilution is not particularly limited, and specific examples thereof include the same as the specific examples of the reaction solvent for the above reaction. The solvent used for dilution may be used alone or in combination of two or more. Among them, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and N-ethyl-2 are used because they dissolve polyamic acid well. -Pyrrolidone and γ-butyrolactone are preferable, and N-methyl-2-pyrrolidone is more preferable.

Further, even a solvent that does not dissolve the polyamic acid by itself can be mixed with the composition for forming a release layer of the present invention as long as the 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, dipropylene glycol, 2-(2-ethoxy) Solvents having a low surface tension such as propoxy)propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, and isoamyl lactate can be mixed appropriately. This is known to improve the uniformity of the coating film when applied to a substrate, and is preferably used in the release layer-forming composition of the present invention.

The concentration of the polyamic acid in the release layer-forming composition of the present invention is appropriately set in consideration of the thickness of the release layer to be prepared, the viscosity of the composition, etc., but is usually about 1 to 30% by mass, preferably It is about 1 to 20 mass %. With such a concentration, a release layer having a thickness of about 0.05 to 5 μm can be obtained with good reproducibility. The concentration of the polyamic acid is adjusted by adjusting the amounts of the diamine and the tetracarboxylic dianhydride that are the raw materials of the polyamic acid, diluting or concentrating the filtrate after filtering the reaction solution, the isolated polyamic acid. It can be adjusted by, for example, adjusting the amount when dissolved in a solvent.

Further, the viscosity of the release layer-forming composition is appropriately set in consideration of the thickness of the release layer to be produced, etc., but in particular, the purpose is to obtain a film having a thickness of about 0.05 to 5 μm with good reproducibility. When it is set, it is usually about 10 to 10,000 mPa·s at 25° C., preferably about 20 to 5,000 mPa·s. Here, the viscosity can be measured at a temperature of the composition of 25° C. by using a commercially available liquid viscometer for measuring viscosity, for example, referring to the procedure described in JIS K7117-2. .. Preferably, a conical plate type (cone plate type) rotational viscometer is used as the viscometer, and 1°34′×R24 is preferably used as a standard cone rotor in the viscometer of the same type. It can be measured under the condition of °C. An example of such a rotational viscometer is TVE-25L manufactured by Toki Sangyo Co., Ltd.

The composition for forming a release layer according to the present invention may contain a component such as a cross-linking agent in addition to the polyamic acid and the organic solvent in order to improve the film strength.

By applying the release layer forming composition of the present invention described above to a substrate, and heating the resulting coating film to thermally imidize the polyamic acid, excellent adhesion to the substrate, and a suitable degree of resin substrate It is possible to obtain a release layer made of a polyimide film having excellent adhesion and appropriate release properties.

When the release layer of the present invention is formed on the substrate, the release layer may be formed on a part of the surface of the substrate or may be formed on the entire surface. The mode of forming the release layer on a part of the surface of the substrate is such that the release layer is formed only in a predetermined range on the surface of the substrate, or the release layer is formed in a pattern such as a dot pattern or a line and space pattern on the entire surface of the substrate. There is a mode of forming the like. In the present invention, the term “base” means a surface of which the release layer-forming composition according to the present invention is applied, which is used for manufacturing a flexible electronic device or the like.

Examples of the substrate (substrate) include glass, plastic (polycarbonate, polymethacrylate, polystyrene, polyester, polyolefin, epoxy, melamine, triacetyl cellulose, ABS, AS, norbornene-based resin, etc.), metal (silicon wafer, etc.), Wood, paper, slate, and the like can be mentioned, and glass is particularly preferable because the release layer obtained from the release layer-forming composition according to the present invention has sufficient adhesion thereto. The surface of the substrate may be made of a single material or may be made of two or more materials. As a mode in which the substrate surface is composed of two or more materials, a certain range of the substrate surface is composed of a certain material, and the remaining surface is composed of another material. , A pattern-like material such as a line-and-space pattern exists in other materials.

The coating method is not particularly limited, and examples thereof include cast coating method, spin coating method, blade coating method, dip coating method, roll coating method, bar coating method, die coating method, inkjet method, printing method (letterpress, intaglio, planographic printing). , Screen printing, etc.) and the like.

The heating temperature for imidization is usually appropriately determined within the range of 50 to 550° C., but is preferably 200° C. or higher, and preferably 500° C. or lower. By setting the heating temperature in this way, it becomes possible to sufficiently promote the imidization reaction while preventing the resulting film from becoming brittle. The heating time varies depending on the heating temperature and cannot be specified unconditionally, but is usually 5 minutes to 5 hours. Further, the imidization ratio may be in the range of 50 to 100%.

As a preferable example of the heating mode in the present invention, after heating at 50 to 100° C. for 5 minutes to 2 hours, the heating temperature is raised stepwise as it is and finally at 375° C. to 450° C. for 30 minutes to 4 hours. The method of heating is mentioned. In particular, after heating at 50 to 100° C. for 5 minutes to 2 hours, it is preferable to heat at more than 100° C. to 375° C. for 5 minutes to 2 hours, and finally to heat at more than 375° C. to 450° C. for 30 minutes to 4 hours.

Examples of equipment used for heating include a hot plate and an oven. The heating atmosphere may be under air or under an inert gas, and may be under normal pressure or under reduced pressure.

The thickness of the release layer is usually about 0.01 to 50 μm, from the viewpoint of productivity, preferably about 0.05 to 20 μm, more preferably about 0.05 to 5 μm, and the thickness of the coating film before heating. To achieve the desired thickness.

The peeling layer described above has excellent adhesion to a substrate, particularly a glass substrate, appropriate adhesion to a resin substrate, and appropriate peelability. Therefore, the release layer according to the present invention, in the manufacturing process of a flexible electronic device, the resin substrate of the device without damaging the resin substrate, together with the circuit formed on the resin substrate, from the substrate It can be preferably used for peeling.

Hereinafter, an example of a method for manufacturing a flexible electronic device using the release layer of the present invention will be described.
The release layer-forming composition according to the present invention is used to form a release layer on a glass substrate by the method described above. A resin solution for forming a resin substrate is applied onto the release layer, and the coating film is heated to form the resin substrate fixed to the glass substrate via the release layer according to the present invention. .. At this time, the resin substrate is formed so as to cover the release layer entirely and have a larger area than the area of the release layer. Examples of the resin substrate include a resin substrate made of polyimide, which is a typical resin substrate for flexible electronic devices, and examples of the resin solution for forming the resin substrate include a polyimide solution and a polyamic acid solution. The resin substrate may be formed by a conventional method.

Next, a desired circuit is formed on the resin substrate fixed to the base body via the release layer according to the present invention, and then the resin substrate is cut along the release layer, for example, and the resin substrate is cut together with the circuit. Is separated from the release layer to separate the resin substrate and the base body. At this time, a part of the substrate may be cut together with the release layer.

On the other hand, it has been reported that the polymer substrate can be suitably peeled from the glass carrier by using the laser lift-off method (LLO method) which has been used in the manufacture of high-brightness LEDs and three-dimensional semiconductor packages in the manufacture of flexible displays. (Japanese Patent Laid-Open No. 2013-147599). In the production of a flexible display, a polymer substrate made of polyimide or the like is provided on a glass carrier, then a circuit including electrodes and the like is formed on the substrate, and finally the substrate is separated from the glass carrier together with this circuit. There is a need. In this peeling process, the LLO method is adopted, that is, when the glass carrier is irradiated with a light beam having a wavelength of 308 nm from the surface opposite to the surface on which the circuit or the like is formed, the light beam having the wavelength is transmitted through the glass carrier and the glass carrier Only the nearby polymer (polyimide) absorbs this light ray and evaporates (sublimates). As a result, it is reported that the peeling of the substrate from the glass carrier can be selectively performed without affecting the circuit or the like provided on the substrate, which determines the performance of the display.

When a desired circuit is formed on the resin substrate fixed to the substrate via the release layer according to the present invention, and then the LLO method is adopted, only the release layer absorbs this light ray and evaporates (sublimates). ) Do. That is, the peeling layer sacrifices (acts as a sacrificial layer), and the peeling of the substrate from the glass carrier can be selectively performed. Since the release layer-forming composition of the present invention has a characteristic of sufficiently absorbing a light beam having a specific wavelength (for example, 308 nm) which enables the LLO method to be applied, it can be used as a sacrificial layer for the LLO method.

Hereinafter, the present invention will be described in more detail with reference to Synthesis Examples, Comparative Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to these Examples. The abbreviations of the compounds used in the following examples and the methods for measuring the number average molecular weight and the weight average molecular weight are as follows.

<abbreviation of compound>
p-PDA: p-phenylenediamine m-PDA: m-phenylenediamine DATP: 4, 4 '' - diamino -p- terphenyl DBA: 3,5-diaminobenzoic acid HAB: 3,3'-dihydroxy benzidine DDE: 4,4'-oxydianiline BAPB: 4,4'-bis(4-aminophenoxy)biphenyl FAPB: 4,4'-bis(4-amino-2-trifluoromethylphenoxy)biphenyl APAB: 5-amino- 2-(4-aminophenyl)-1H-benzimidazole APAB-E: 4-aminophenyl-4'-aminobenzoate 6FAP: 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane TFMB:2 2,2'-bis(trifluoromethyl)biphenyl-4,4'-diamine BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride TAHQ: p-phenylene bis(trimellitic acid monoester acid (Anhydrous)
PMDA: pyromellitic dianhydride BPTME: p-biphenylene bis (trimellitic acid monoester acid anhydride)
BPODA: 4,4′-(biphenyl-4,4′-diylbisoxy)bisphthalic acid dianhydride CF3-BP-TMA:N,N′-[2,2′-bis(trifluoromethyl)biphenyl-4 ,4'-Diyl]bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carbamide)
6FDA: 4,4'-(hexafluoroisopropylidene) diphthalic anhydride CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride IPBBT: N,N'-isophthalbis(benzoxazoline-2-thione )
NMP: N-methyl-2-pyrrolidone BCS: butyl cellosolve

<Measurement of weight average molecular weight and molecular weight distribution>
The weight average molecular weight (Mw) and the molecular weight distribution (Mw/Mn) of the polymer were measured by a GPC device manufactured by JASCO Corporation (column: Showa Denko OHpak SB803-HQ and OHpak SB804-HQ; eluent). : Dimethylformamide/LiBr.H ₂ O (29.6 mM)/H ₃ PO ₄ (29.6 mM)/THF (0.1% by mass); flow rate: 1.0 mL/min; column temperature: 40° C.; Mw: The standard polystyrene conversion value) was used (the same in the following examples and comparative examples).

[1] Synthesis of Polymer Polyamic acid and polybenzoxazole precursor were synthesized by the following method.
The polymer was not isolated from the obtained polymer-containing reaction liquid, but the reaction solution was diluted as described below to prepare a resin substrate-forming composition or a release layer-forming composition.

[Synthesis Example S1] Synthesis of polyamic acid S1 20.261 g (187 mmol) of p-PDA and 12.206 g (47 mmol) of DATP were dissolved in 617.4 g of NMP. The obtained solution was cooled to 15° C., PMDA (50.112 g, 230 mmol) was added thereto, the temperature was raised to 50° C. in a nitrogen atmosphere, and the reaction was carried out for 48 hours to obtain polyamic acid S1. The polyamic acid S1 had Mw of 82,100 and Mw/Mn of 2.7.

[Synthesis Example S2] Synthesis of polyamic acid S2 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 to obtain polyamic acid S2. The polyamic acid S2 had an Mw of 107,300 and an Mw/Mn of 4.6.

[Synthesis Example S3] Synthesis of polyamic acid S3 17.8 g (56 mmol) of TFMB, 0.4 g (1 mmol) of BAPB and 2.5 g (23 mmol) of p-PDA were dissolved in 430 g of NMP. To the obtained solution, 6.3 g (14 mmol) of 6FDA and 42.8 g (64 mmol) of CF3-BP-TMA were added and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid S3. The polyamic acid S3 had an Mw of 38,700 and an Mw/Mn of 2.1.

[Synthesis example S4] Synthesis of polyamic acid S4 DDE (30.6 g, 153 mmol) was dissolved in NMP (440 g). 29.4 g (150 mmol) of CBDA was added to the obtained solution and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid S4. The polyamic acid S4 had an Mw of 29,800 and an Mw/Mn of 2.2.

[Synthesis example L1] Synthesis of polyamic acid L1 2.054 g (19 mmol) of p-PDA was dissolved in 88 g of NMP. To the obtained solution, 9.946 g (19 mmol) of BPTME was added and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L1. The polyamic acid L1 had an Mw of 57,500 and an Mw/Mn of 3.0.

[Synthesis example L2] Synthesis of polyamic acid L2 1.836 g (17 mmol) of p-PDA and 0.287 g (1.9 mmol) of DBA were dissolved in 88 g of NMP. To the obtained solution, 9.878 g (18 mmol) of BPTME was added and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L2. The polyamic acid L2 had an Mw of 65,100 and an Mw/Mn of 3.0.

[Synthesis example L3] Synthesis of polyamic acid L3 1.367 g (13 mmol) of p-PDA and 1.172 g (5.4 mmol) of HAB were dissolved in 88 g of NMP. To the resulting solution, 9.461 g (18 mmol) of BPTME was added and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L3. The Mw of the polyamic acid L3 was 43,600 and Mw/Mn2.6.

[Synthesis example L4] Synthesis of polyamic acid L4 3.984 g (15 mmol) of DATP was dissolved in 88 g of NMP. 8.016 g (15 mmol) of BPTME was added to the obtained solution, and the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L4. The polyamic acid L4 had an Mw of 42,600 and an Mw/Mn of 3.9.

[Synthesis Example L5] Synthesis of polyamic acid L5 5.17 g (14 mmol) of BAPB was dissolved in 88 g of NMP. BPTME (6.83 g, 13 mmol) was added to the obtained solution, and the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L5. The polyamic acid L5 had Mw of 52,100 and Mw/Mn of 2.7.

[Synthesis example L6] Synthesis of polyamic acid L6 5.89 g (12 mmol) of FAPB was dissolved in 88 g of NMP. To the resulting solution, 6.11 g (11 mmol) of BPTME was added and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L6. The polyamic acid L6 had Mw of 87,700 and Mw/Mn of 3.3.

[Synthesis example L7] Synthesis of polyamic acid L7 3.60 g (16 mmol) of APAB was dissolved in 88 g of NMP. To the obtained solution, 8.40 g (16 mmol) of BPTME was added and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L7. The polyamic acid L7 had Mw of 58,300 and Mw/Mn of 2.8.

[Synthesis example L8] Synthesis of polyamic acid L8 2.322 g (12 mmol) of DDE was dissolved in 35.2 g of NMP. PMDA 2.478g (11 mmol) was added to the obtained solution, and it was made to react at 23 degreeC for 24 hours under nitrogen atmosphere, and the polyamic acid L8 was obtained. The polyamic acid L8 had an Mw of 22,600 and an Mw/Mn of 2.1.

[Synthesis example L9] Synthesis of polyamic acid L9 1.762 g (7 mmol) of DATP was dissolved in 35.2 g of NMP. To the resulting solution was added TAHQ (3.038 g, 7 mmol), and the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L9. The polyamic acid L9 had an Mw of 61,300 and an Mw/Mn of 3.3.

[Synthesis example L10] Synthesis of polyamic acid L10 0.899 g (8 mmol) of p-PDA was dissolved in 35.2 g of NMP. 3.900 g (8 mmol) of BPODA was added to the obtained solution, and the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L10. The polyamic acid L10 had an Mw of 17,300 and an Mw/Mn of 2.4.

[Synthesis example L11] Synthesis of polyamic acid L11 1.713 g (7 mmol) of DATP was dissolved in 35.2 g of NMP. To the resulting solution, 3.086 g (6 mmol) of BPODA was added and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L11. The polyamic acid L11 had an Mw of 27,000 and an Mw/Mn of 2.4.

[Synthesis Example L12] Synthesis of polyamic acid L12 0.931 g (9 mmol) of p-PDA was dissolved in 35.2 g of NMP. 3.868 g (8 mmol) of TAHQ was added to the obtained solution and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L12. The polyamic acid L12 had Mw of 45,000 and Mw/Mn of 2.7.

[Synthesis Example L13] Synthesis of polyamic acid L13 0.839 g (8 mmol) of p-PDA and 0.093 g (1 mmol) of m-PDA were dissolved in 35.2 g of NMP. 3.868 g (8 mmol) of TAHQ was added to the obtained solution and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L13. The polyamic acid L13 had Mw of 39,100 and Mw/Mn of 2.6.

[Synthesis example L14] Synthesis of polyamic acid L14 0.652 g (6 mmol) of p-PDA and 0.280 g (3 mmol) of m-PDA were dissolved in 35.2 g of NMP. To the resulting solution was added TAHQ (3.868 g, 8 mmol), and the mixture was reacted under a nitrogen atmosphere at 23° C. for 24 hours to obtain polyamic acid L14. The polyamic acid L14 had an Mw of 42,700 and an Mw/Mn of 2.6.

[Synthesis Example L15] Synthesis of polyamic acid L15 0.931 g (9 mmol) of m-PDA was dissolved in 35.2 g of NMP. 3.868 g (8 mmol) of TAHQ was added to the obtained solution and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L15. The polyamic acid L15 had Mw of 36,100 and Mw/Mn of 2.5.

<Synthesis example L16> Synthesis of polyamic acid L16 0.816 g (8 mmol) of p-PDA and 0.218 g (1 mmol) of DATP were dissolved in 35.2 g of NMP. TAHQ (3.765 g, 8 mmol) was added to the obtained solution, and the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L16. The polyamic acid L16 had an Mw of 43,800 and an Mw/Mn of 2.5.

[Synthesis Example L17] Synthesis of polyamic acid L17 0.603 g (6 mmol) of p-PDA and 0.622 g (2 mmol) of DATP were dissolved in 35.2 g of NMP. To the resulting solutions was added TAHQ (3.575 g, 8 mmol), and the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L17. The polyamic acid L17 had Mw of 46,000 and Mw/Mn of 2.6.

[Synthesis example L18] Synthesis of polyamic acid L18 0.832 g (8 mmol) of p-PDA and 0.130 g (1 mmol) of DBA were dissolved in 35.2 g of NMP. To the resulting solution was added TAHQ (3.838 g, 8 mmol), and the mixture was reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L18. The polyamic acid L18 had an Mw of 57,000 and an Mw/Mn of 3.0.

[Synthesis example L19] Synthesis of polyamic acid L19 0.822 g (8 mmol) of p-PDA and 0.183 g (1 mmol) of HAB were dissolved in 35.2 g of NMP. TAHQ (3.794 g, 8 mmol) was added to the obtained solution, and the mixture was allowed to react at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L19. The polyamic acid L19 had an Mw of 54,200 and an Mw/Mn of 2.7.

[Synthesis Example L20] Synthesis of polyamic acid L20 0.616 g (6 mmol) of p-PDA and 0.528 g (2 mmol) of HAB were dissolved in 35.2 g of NMP. 3.655 g (8 mmol) of TAHQ was added to the obtained solution and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L20. The polyamic acid L20 had Mw of 55,900 and Mw/Mn of 2.6.

[Synthesis example L21] Synthesis of polyamic acid L21 APAB-E (1.239 g, 5 mmol) was dissolved in NMP (17.6 g). PMDA 1.160g (5 mmol) was added to the obtained solution, and it was made to react at 23 degreeC under nitrogen atmosphere for 24 hours, and polyamic acid L21 was obtained. The polyamic acid L21 had an Mw of 20,900 and an Mw/Mn of 2.1.

[Synthesis example L22] Synthesis of polyamic acid L22 APAB-E (1.060 g, 5 mmol) was dissolved in NMP (17.6 g). To the obtained solution, 1.339 g (5 mmol) of BPDA was added and reacted at 23° C. for 24 hours under a nitrogen atmosphere to obtain polyamic acid L22. The polyamic acid L22 had Mw of 26,600 and Mw/Mn of 2.3.

[Comparative Synthesis Example 1] Synthesis of polybenzoxazole precursor B1 5.49 g (0.015 mol) of 6FAP was dissolved in 27 g of NMP. IPBBT 6.48g (0.015mol) was added to the obtained solution, and it was made to react at 23 degreeC under nitrogen atmosphere for 3 hours. Then, this solution was poured into 300 g of pure water and stirred for 24 hours, and then the precipitate was filtered. Then, it dried under reduced pressure and the polybenzoxazole precursor B1 was obtained. The polybenzoxazole precursor B1 had an Mw of 21,000 and an Mw/Mn of 3.9.

[2] Preparation of Resin Substrate Forming Composition The reaction liquids obtained in Synthesis Examples S1 to S4 were used as the resin substrate forming compositions W, X, Y and Z, respectively.

[3] Preparation of release layer-forming composition [Example 1-1]
BCS was added to the reaction solution obtained in Synthesis Example L1, and the mixture was diluted with NMP so that the polymer concentration was 5% by mass and the BCS was 20% by mass to obtain a release layer forming composition.

[Examples 1-2 to 1-22]
A release layer-forming composition was obtained in the same manner as in Example 1-1, except that the reaction solutions obtained in Synthesis Examples L2 to L22 were used instead of the reaction solutions obtained in Synthesis Example L1. It was

[Comparative Example 1]
The reaction liquid obtained in Comparative Synthesis Example 1 was diluted with NMP so that the polymer concentration was 5% by mass to obtain a composition.

[4] Formation of Release Layer and Evaluation thereof [Example 2-1]
The composition for peeling layer formation obtained in Example 1-1 was applied onto a 100 mm×100 mm glass substrate (hereinafter the same) as a glass substrate using a spin coater (conditions: 3000 rpm for about 30 seconds). ..
Then, the obtained coating film is heated at 80° C. for 10 minutes using a hot plate, and thereafter, is heated at 300° C. for 30 minutes using an oven, and the heating temperature is raised to 400° C. (10° C./minute). ) And further heated at 400° C. for 30 minutes to form a peeling layer having a thickness of about 0.1 μm on the glass substrate. During the temperature rise, the film-coated substrate was not taken out of the oven, but was heated in the oven.

[Examples 2-2 to 2-22]
Example 2-1 except that the release layer-forming compositions obtained in Examples 1-2 to 1-22 were used instead of the release layer-forming compositions obtained in Example 1-1, respectively. A peeling layer was formed in the same manner as in.

[Example 2-23]
The composition for release layer formation obtained in Example 1-12 was applied onto a 100 mm×100 mm glass substrate using a spin coater (conditions: rotation speed 3000 rpm for about 30 seconds).
Then, the obtained coating film is heated at 80° C. for 10 minutes using a hot plate, and then at 140° C. for 30 minutes using an oven, and the heating temperature is raised to 250° C. (2° C./minute). ) And further heated at 250° C. for 60 minutes to form a peeling layer having a thickness of about 0.1 μm on the glass substrate. During the temperature rise, the film-coated substrate was not taken out of the oven, but was heated in the oven.

[Example 2-24]
The composition for release layer formation obtained in Example 1-8 was applied onto a 100 mm×100 mm glass substrate as a glass substrate using a spin coater (conditions: 3000 rpm for about 30 seconds).
Then, the obtained coating film is heated at 80° C. for 10 minutes using a hot plate, and thereafter, is heated at 300° C. for 30 minutes in a nitrogen atmosphere using an oven, and the heating temperature is raised to 400° C. (10 C./min.) and further heated at 400.degree. C. for 60 minutes and finally at 500.degree. C. for 10 minutes to form a peeling layer having a thickness of about 0.1 .mu.m on the glass substrate. During the temperature rise, the film-coated substrate was not taken out of the oven, but was heated in the oven.

[Example 2-25]
A resin thin film was formed in the same manner as in Example 2-24, except that the composition obtained in Example 1-12 was used instead of the composition for forming a release layer obtained in Example 1-8. Formed.

[Comparative example 2]
A resin thin film was formed in the same manner as in Example 2-1, except that the composition obtained in Comparative Example 1 was used instead of the composition for forming a release layer obtained in Example 1-1. ..

[5] Evaluation of peelability [Examples 3-1 to 3-47, Comparative example 3]
The peelability of the peeling layer and the glass substrate obtained in Examples 2-1 to 2-25 and the peelability of the peeling layer (resin thin film) and the resin substrate were confirmed. A resin substrate made of polyimide was used as the resin substrate.
First, the cross-cut of the release layer on the glass substrate with the release layer obtained in Examples 2-1 to 2-25 (vertical and horizontal 1 mm interval, the same applies hereinafter), and the resin substrate/the resin substrate on the glass substrate with the release layer -100 cross-cuts were performed by cross-cutting the release layer. That is, by this cross-cut, 100 squares of 1 mm square were formed.
Then, an adhesive tape was attached to this 100 muscat portion, the tape was peeled off, and the degree of peeling was evaluated based on the following criteria (5B-0B, B, A, AA) (Examples 3-1 to 3-3- 47). Further, the same test was performed using the glass substrate with a resin thin film obtained in Comparative Example 2 according to the above method (Comparative Example 3). The results are shown in Table 1. The evaluation criteria for peelability in Table 1 are as follows.

5B: 0% peeling (no peeling)
4B: Peeling less than 5% 3B: Peeling 5 to 15% 2B: Peeling less than 15 to 35% 1B: Peeling less than 35 to 65% 0B: Peeling less than 65% to 80% B: 80% to 95% Peeling less than A: Peeling less than 95% to 100% AA: 100% peeling (all peeled)

The resin substrates of Examples 3-1 to 3-41, 3-44 to 3-47 and Comparative Example 3 were formed by the following method.
Using a bar coater (gap: 250 μm), either the resin substrate-forming composition W or X was applied onto the release layer (resin thin film) on the glass substrate. Then, the obtained coating film is heated at 80° C. for 10 minutes using a hot plate, and then at an oven for 30 minutes at 140° C., and the heating temperature is increased to 210° C. (10° C./minute). , The same shall apply hereinafter), and the heating temperature is raised to 300° C. for 30 minutes at 210° C., the heating temperature is raised to 400° C. for 30 minutes at 300° C., and the heating temperature is raised to 400° C. for 60 minutes. A polyimide substrate having a thickness of about 20 μm was formed. During the temperature rise, the film-coated substrate was not taken out from the oven, but was heated in the oven.

The resin substrates of Examples 3-42 to 3-43 were formed by the following method.
Using a bar coater (gap: 50 μm), either the resin substrate forming composition Y or Z was applied onto the release layer on the glass substrate. Then, the obtained coating film is heated at 80° C. for 10 minutes using a hot plate, and then at 140° C. for 30 minutes using an oven, and the heating temperature is raised to 250° C. (2° C./minute). ) And heated at 250° C. for 60 minutes to form a polyimide substrate having a thickness of about 0.8 μm on the release layer. During the temperature rise, the film-coated substrate was not taken out from the oven, but was heated in the oven.

As shown in Tables 1 and 2, it was found that the peeling layer of the example had excellent adhesion to the glass substrate and excellent peeling property to the resin substrate. On the other hand, the peeling layer of the comparative example did not peel from the resin substrate and the glass substrate and did not function as a peeling layer.

[6] Evaluation of transmittance [Example 4]
The composition for peeling layer formation obtained in Example 2-8 was applied as a glass substrate on a 100 mm×100 mm glass substrate (the same applies hereinafter) using a spin coater (conditions: rotation speed 800 rpm for about 30 seconds). ..
Then, the obtained coating film is heated at 80° C. for 10 minutes using a hot plate, and thereafter, is heated at 300° C. for 30 minutes using an oven, and the heating temperature is raised to 400° C. (10° C./minute). ) And further heated at 400° C. for 30 minutes to form a peeling layer having a thickness of about 0.4 μm on the glass substrate. During the temperature rise, the film-coated substrate was not taken out of the oven, but was heated in the oven. The transmittance of the obtained film was measured using an ultraviolet-visible spectrophotometer (SIMADSU UV-2550 model number, manufactured by Shimadzu Corporation).
The results are shown in Figure 1. The transmittance of the obtained film was 1% or less with respect to a wavelength of 308 nm, which was a transmittance that can be used as a sacrificial layer.

Claims (9)

A polyamic acid obtained by reacting an aromatic diamine and an aromatic tetracarboxylic dianhydride, and an organic solvent,
The aromatic diamine includes an aromatic diamine containing an ester bond which is at least one selected from the group consisting of formulas (A4) to (A6), (A13) to (A24) and (A34) to (A39). And/or the aromatic tetracarboxylic dianhydride contains an ester bond which is at least one selected from the group consisting of formulas (B1), (B2), (B5) to (B7) and (B11). A composition for forming a release layer, comprising an aromatic tetracarboxylic dianhydride.

The release layer-forming composition according to claim 1, wherein the aromatic tetracarboxylic dianhydride further contains an aromatic tetracarboxylic dianhydride containing neither an ester bond nor an ether bond. The release layer-forming composition according to claim 2 , wherein the aromatic tetracarboxylic dianhydride containing neither an ester bond nor an ether bond contains a benzene skeleton, a naphthyl skeleton or a biphenyl skeleton. The peeling layer forming according to claim 3 , wherein the aromatic tetracarboxylic dianhydride containing neither an ester bond nor an ether bond is at least one selected from the group consisting of formulas (C1) to (C12). Composition.

The organic solvent, amides of the formula (S1), according to claim 1-4 comprising at least one selected from the amides of the formula (S2) amides represented by and Equation (S3) The composition for forming a release layer according to any one of 1.

(In the formula, R ¹ and R ² independently represent an alkyl group having 1 to 10 carbon atoms. R ³ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. h is a natural number. Represents.) A release layer formed using the release layer forming composition according to any one of claims 1-5. A method of manufacturing a flexible electronic device including a resin substrate, comprising using the release layer according to claim 6 . A method for manufacturing a touch panel sensor including a resin substrate, wherein the release layer according to claim 6 is used. Said resin substrate, a manufacturing method according to claim 7 or 8 which is a substrate made of polyimide.

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