laminated body

Abstract

The present invention provides a composition for forming a release layer, comprising polyamide represented by the following formula (1) and an organic solvent. (In the formula, X is an aromatic group represented by the following formula (X1), Y is a divalent organic group containing an aromatic group with an ether bond or an ester bond and without a fluorine atom, and n represents a natural number)

Description

[Technical Field]

[0001] The present invention relates to a composition for forming a release layer. [Previous Technology]

[0002] In recent years, in addition to the requirements for thinness and lightness, electronic devices have also been required to be flexible. As a result, there is a need to replace the heavy, fragile and inflexible glass substrates with lightweight flexible plastic substrates.

[0003] In particular, for next-generation displays, there is a pursuit to develop active-matrix full-color TFT display panels using lightweight flexible plastic substrates (hereinafter also referred to as resin substrates). Furthermore, for touch displays, materials corresponding to flexibility, such as transparent electrodes or resin substrates for touch panels used in conjunction with display panels, have been developed. As for transparent electrodes, in addition to the previously used ITO, other transparent electrode materials proposed include flexible transparent conductive polymers such as PEDOT, metal nanowires, and hybrid systems thereof (Patent Documents 1-4).

[0004] On the other hand, the substrate of the touch panel film has also been developed from glass to thin sheets made of plastics such as polyethylene terephthalate (PET), polyimide, cyclic olefin polymers, and acrylic resin, and thus has a flexible transparent flexible touch screen panel (Patent Documents 5-7).

[0005] Generally, flexible touch screen panels are manufactured by forming a release (adhesive) layer on a support substrate such as a glass substrate in order to ensure stable production and peelability (Patent Document 8). The release layer needs to not peel off from the support substrate during the process, but on the other hand, it needs to have low peeling force during peeling.

[0006] Furthermore, transparent flexible touchscreen panels typically use transparent plastic substrates, but these transparent plastics mostly have low glass transition temperatures (Tg). Therefore, when using transparent plastic substrates, the device manufacturing process must involve firing at a temperature exceeding the Tg of the plastic. In such cases, the release layer adheres closely to the resin substrate, making it difficult to peel the resin substrate off the support substrate after device manufacturing. [Prior Art Documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 2012 / 147235 [Patent Document 2] Japanese Patent Application Publication No. 2009-283410 [Patent Document 3] Japanese Patent Application Publication No. 2010-507199 [Patent Document 4] Japanese Patent Application Publication No. 2009-205924 [Patent Document 5] International Publication No. 2017 / 002664 [Patent Document 6] International Publication No. 2016 / 160338 [Patent Document 7] Japanese Patent Application Publication No. 2015-166145 [Patent Document 8] Japanese Patent Application Publication No. 2014-102490 [Summary of the Invention]

[0008] [The problem the invention aims to solve]

[0009] This invention was made in view of the foregoing circumstances, and its object is to provide a composition for forming a release layer that can be peeled off without damaging the substrate of a flexible electronic device. [Means for solving the problem]

[0010] As a result of repeated and active investigations in order to achieve the above-mentioned objective, the inventors discovered that a composition comprising polyamide with a specific structure and an organic solvent not only has excellent adhesion to the substrate and moderate adhesion and moderate peelability to the resin substrate used as a flexible electronic device, but also can obtain a release layer that maintains its adhesion and peelability even when the resin substrate is fired at a temperature exceeding Tg. Thus, the present invention was completed.

[0011] That is, the present invention provides the following composition for forming a release layer. 1. A composition for forming a release layer comprising polyamide represented by the following formula (1) and an organic solvent, (where X is an aromatic group represented by the following formula (X1), Y is a divalent organic group containing an aromatic group having an ether bond or an ester bond and not containing a fluorine atom, and n represents a natural number). 2. The composition for forming a release layer as described in 1, wherein the above-mentioned Y is any one of the aromatic groups represented by the following formulas (Y1) to (Y8), (where R1 to R96 independently represent hydrogen atoms, chlorine atoms, bromine atoms, iodine atoms; alkyl groups having 1 to 10 carbon atoms that can be substituted by chlorine atoms, bromine atoms, or iodine atoms; or aryl groups having 6 to 20 carbon atoms that can be substituted by chlorine atoms, bromine atoms, or iodine atoms). 3. The composition for forming a release layer as described in 2, wherein the above-mentioned Y is any one of the aromatic groups represented by the following formulas (Y9) to (Y13). 4. A release layer forming composition according to any one of claims 1 to 3, wherein the organic solvent is selected from at least one having a structure represented by the following formulas (S1) to (S7), (where R1s to R8s independently represent hydrogen atoms or alkyl groups having 1 to 10 carbon atoms, R9s and R10s independently represent hydrogen atoms, alkyl groups having 1 to 10 carbon atoms, or amide groups having 1 to 10 carbon atoms, and b and m represent natural numbers). 5. A release layer obtained from a release layer forming composition according to any one of claims 1 to 4. 6. A method for manufacturing a resin substrate using a release layer as described in claim 5. 7. A manufacturing method according to claim 6, wherein the resin substrate is a polyimide substrate. [Effects of the Invention]

[0012] By using the release layer forming composition of the present invention, a film with excellent adhesion to the substrate and moderate adhesion and release properties to the resin substrate can be reproducibly obtained. In particular, even when the resin substrate is fired at a temperature exceeding its Tg, the aforementioned adhesion and release properties do not change, making it suitable for use in resin substrates for fixing flexible touch screen panels. By using the composition of the present invention, the resin substrate formed on the substrate or the circuits disposed thereon are not damaged during the manufacturing process of flexible electronic devices, and the resin substrate and the circuits can be peeled off from the substrate together. Therefore, the release layer forming composition of the present invention can help simplify the manufacturing process of flexible electronic devices with resin substrates or improve their yield.

Implementation Method

[0013] The present invention will now be described in more detail. The composition for forming the release layer of the present invention comprises polyamide and an organic solvent represented by the following formula (1). Here, the release layer in the present invention is a layer disposed directly above a substrate such as a glass substrate for a specific purpose. As a typical example, in the manufacturing process of flexible electronic devices, it is disposed between a substrate and a resin substrate of a flexible electronic device made of a resin such as polyimide, for fixing the resin substrate in a specific process, and after electronic circuits are formed on the resin substrate, the resin substrate can be easily peeled off from the substrate.

[0014]

[0015] In the formula, X is an aromatic group represented by the following formula (X1), and Y is a divalent organic group containing an aromatic group with an ether bond or an ester bond and without a fluorine atom. n represents a natural number, preferably an integer greater than 2.

[0016]

[0017] As exemplified by Y above, it is an aromatic group having a structure in which multiple aromatic rings having 6 to 20 carbon atoms are linked by ester bonds or ether bonds. Specific examples of the aforementioned aromatic rings include benzene rings, biphenyl rings, naphthalene rings, anthracene rings, phenanthrene rings, etc. Among these, from the viewpoint of ensuring the solubility of polyacrylic acid in organic solvents, it is preferable to include a structure in which 2 or 3 aromatic rings are linked by ester bonds or ether bonds. More preferably, it is an aromatic group represented by the following formulas (Y1) to (Y8).

[0018]

[0019] In the formula, R1~R96 independently represent hydrogen atom, chlorine atom, bromine atom, iodine atom; alkyl group with 1 to 10 carbon atoms that can be replaced by chlorine atom, bromine atom or iodine atom; or aryl group with 6 to 20 carbon atoms that can be replaced by chlorine atom, bromine atom or iodine atom.

[0020] Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl.

[0021] Examples of aryl groups having 6 to 20 carbon atoms include phenyl, tolyl, 1-naphthyl, 2-naphthyl, 1-anthrayl, 2-anthrayl, 9-anthrayl, 1-phenanthyl, 2-phenanthyl, 3-phenanthyl, 4-phenanthyl and 9-phenanthyl.

[0022] In these, R1 to R96 are preferably hydrogen atoms, alkyl or phenyl atoms having 1 to 3 carbon atoms, more preferably hydrogen atoms, methyl or ethyl atoms, and even more preferably hydrogen atoms.

[0023] The above-mentioned Y is preferably an aromatic group represented by the following formulas (Y1-1) to (Y8-1).

[0024] (In the formula, R1~R96 are the same as above).

[0025] As a more specific example of the above Y, an example is an aromatic group represented by the following formulas (Y9) to (Y13), but it is not limited thereto.

[0026]

[0027] The polyamide represented by the above formula (P1) can be obtained by reacting the following aromatic diamine component with the aromatic tetracarboxylic acid dianhydride component.

[0028] The aromatic diamine can be an aromatic diamine containing ether bonds or ester bonds and free of fluorine atoms. Examples of such aromatic diamines are diamines having a plurality of aromatic rings with 6 to 20 carbon atoms linked by ester bonds or ether bonds. Specific examples of the aforementioned aromatic rings include benzene rings, biphenyl rings, naphthalene rings, anthracene rings, phenanthrene rings, etc. Among these, based on the viewpoint of ensuring the solubility of polyacrylic acid in organic solvents, it is preferable to have a diamine having a structure in which 2 or 3 aromatic rings are linked by ester bonds or ether bonds, and more preferably an aromatic diamine having a structure represented by the above formulas (Y1) to (Y8).

[0029] In this invention, the following are preferred examples of the above-mentioned aromatic diamine.

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036] In this invention, diamines other than the aforementioned aromatic diamines may also be used together.

[0037] Such diamines may be either aliphatic or aromatic, but from the viewpoint of ensuring the strength and heat resistance of the obtained film, it is preferable to be an aromatic diamine that does not contain any of the ether bonds, ester bonds, or fluorine atoms.

[0038] Specific examples include diamines containing one benzene ring, such as 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-xylenediamine, p-xylenediamine, etc.; 1,2-naphthylenediamine, 1,3- Naphthalenediamine, 1,4-naphthyldiamine, 1,5-naphthyldiamine, 1,6-naphthyldiamine, 1,7-naphthyldiamine, 1,8-naphthyldiamine, 2,3-naphthyldiamine, 2,6-naphthyldiamine, 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'-diaminobenzylaniline, 3,3'-dichlorobenzylaniline, 3,3'-dimethylbenzylaniline, 2,2'-dimethylbenzylaniline, 3,3'-diaminodiphenylmethane, 3,4' -Diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 3,3'-diaminodiphenyl sulfene, 3,4'-diaminodiphenyl sulfene, 4,4'-diaminodiphenyl sulfene, etc., containing two benzene rings; 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 ... Diamines containing three benzene rings, such as 1,4-bis(4-aminophenyl)benzene, 1,3-bis(3-aminophenylthio)benzene, 1,3-bis(4-aminophenylthio)benzene, 1,4-bis(4-aminophenylthio)benzene, 1,3-bis(3-aminophenylsulfonyl)benzene, 1,3-bis(4-aminophenylsulfonyl)benzene, 1,4-bis(4-aminophenylsulfonyl)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, etc., are not limited to these. One of these may be used alone, or two or more may be used in combination.

[0039] In this invention, when using a diamine other than an aromatic diamine containing ether or ester bonds and free of fluorine atoms, the amount of the aromatic diamine containing ether or ester bonds and free of fluorine atoms used is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and still more preferably 95 mol% or more. By using such amounts, a film with excellent adhesion to the substrate and moderate adhesion and moderate peel strength to the resin substrate can be reproducibly obtained.

[0040] In this invention, as a preferred specific example of an aromatic tetracarboxylic acid dianhydride component comprising an aromatic group represented by the above formula (X1), the following examples are provided.

[0041]

[0042] In this invention, other tetracarboxylic acid dianhydrides may also be used together with aromatic tetracarboxylic acid dianhydrides that contain aromatic groups represented by the above formula (X1).

[0043] These tetracarboxylic dianhydrides may be either aliphatic or aromatic tetracarboxylic dianhydrides, but from the viewpoint of ensuring the strength and heat resistance of the obtained film, it is preferred to be an aromatic tetracarboxylic dianhydride that does not contain either ether or ester bonds.

[0044] Specific examples include pyromellitic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, naphthalene-1,2,3,4-tetracarboxylic dianhydride, 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, biphenyl-2,2',3,3'-tetracarboxylic dianhydride, biphenyl-2,2,3',4'-tetracarboxylic dianhydride, biphenyl-3,3',4,4'-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, phenanthrene-1,2,9,10-tetracarboxylic dianhydride, phenanthrene-2,3,5,6-tetracarboxylic dianhydride, phenanthrene-2,3,6,7-tetracarboxylic dianhydride, phenanthrene-2,3,9,10-tetracarboxylic dianhydride, phenanthrene-3,4,5,6-tetracarboxylic dianhydride, phenanthrene-3,4,9,10-tetracarboxylic dianhydride, etc., but not limited to these. Each of these can be used alone or in combination of two or more.

[0045] In particular, as an aromatic tetracarboxylic acid dianhydride that does not contain either ether or ester bonds, from the viewpoint of ensuring heat resistance, it is preferably selected from at least one of the group consisting of formulas (C1) to (C12), and more preferably selected from at least one of the group consisting of formulas (C1) and (9).

[0046]

[0047] In this invention, when using a tetracarboxylic dianhydride other than the aromatic tetracarboxylic dianhydride component containing the aromatic group represented by the above formula (X1) together, the amount of the aromatic tetracarboxylic dianhydride component containing the aromatic group represented by the above formula (X1) used is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and still more preferably 95 mol% or more in all tetracarboxylic dianhydrides. By using such amounts, a film having sufficient adhesion to the substrate and moderate adhesion and moderate peelability to the resin substrate can be obtained with good reproducibility.

[0048] By reacting the diamine and tetracarboxylic acid dianhydride described above, the polyamide contained in the release layer forming composition of the present invention can be obtained.

[0049] The organic solvents used in these reactions are not particularly limited as long as they do not adversely affect the reaction. However, specific examples include p-cresol, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylmethoxyamine, 3-methoxy-N,N-dimethylpropionic acid, 3-ethoxy-N,N-dimethylpropionic acid, 3-propoxy-N,N-dimethylpropionic acid, 3-isopropoxy-N,N-dimethylpropionic acid, 3-butoxy-N,N-dimethylpropionic acid, 3-tert-butoxy-N,N-dimethylpropionic acid, 3-tert-butoxy-N,N-dimethylpropionic acid, γ-butyrolactone, etc. Furthermore, organic solvents can be used alone or in combination of two or more.

[0050] The reaction temperature during the synthesis of polyacrylic acid can be appropriately set within the range of the melting point to boiling point of the solvent used, usually around 0~100℃. However, in order to prevent amide formation in the resulting polyacrylic acid solution and maintain a high content of polyacrylic acid units, it is preferably around 0~70℃, more preferably around 0~60℃, and even more preferably around 0~50℃. The reaction time depends on the reaction temperature or the reactivity of the raw materials and therefore cannot be specified uniformly, but it is usually around 1~100 hours.

[0051] By means of the method described above, a reaction solution containing the desired polyacrylic acid can be obtained. Furthermore, the ends of the polyacrylic acid can also be capped for purposes such as adjusting peel strength. In this case, methods such as reacting polyacrylic acid with phthalic anhydride after generating an excess of diamine, or reacting polyacrylic acid with aniline after generating an excess of dianhydride, are sufficient.

[0052] The weight-average molecular weight of the above-mentioned polyamide is preferably 5,000 to 1,000,000, more preferably 10,000 to 500,000, and from a processability point of view, more preferably 15,000 to 200,000. Furthermore, the weight-average molecular weight of the present invention is the average molecular weight obtained by conversion from standard polystyrene analyzed by gel permeation chromatography (GPC).

[0053] In this invention, the above-mentioned reaction solution is typically filtered, and the filtrate, either directly or after dilution or concentration, is used as the composition for forming the release layer of this invention. This not only reduces the introduction of impurities that could cause deterioration in the adhesion or peelability of the resulting release layer, but also allows for efficient and good acquisition of the composition for forming the release layer. Furthermore, after isolating the polyacrylic acid from the above-mentioned reaction solution, it can be redissolved in a solvent to form the composition for forming the release layer. Examples of solvents used in this case include organic solvents used in the aforementioned reaction.

[0054] The composition system for forming the release layer of the present invention includes an organic solvent. The organic solvent can be the same as the reaction solvent of the above-described reaction, but in order to fully dissolve the polyamide of the present invention and easily prepare a composition with high uniformity, it is preferred to use an organic solvent selected from the group consisting of amides, alcohols, esters, ethers and ketones, and especially preferably includes at least one having a structure represented by the following formulas (S1) to (S7).

[0055]

[0056] In the above formula, R1s to R8s independently represent hydrogen atoms or alkyl groups with 1 to 10 carbon atoms, preferably 1 to 5. R9s and R10s independently represent hydrogen atoms, alkyl groups with 1 to 10 carbon atoms, preferably 1 to 5, or acetyl groups with 1 to 10 carbon atoms, preferably 1 to 5. b represents a natural number, preferably 1 to 5, more preferably 1 to 3. m represents a natural number, preferably 1 to 5, more preferably 1 to 3.

[0057] Specific examples of alkyl groups having 1 to 10 carbon atoms may be linear, branched, or cyclic, such as methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl-n-butyl, 1,1-dimethyl-n-propyl, 1,2-dimethyl-n-propyl, 2,2-dimethyl-n-propyl, 1-ethyl-n-propyl, cyclopentyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-propyl, etc. 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl-n-butyl, 2,2-dimethyl-n-butyl, 2,3-dimethyl-n-butyl, 3,3-dimethyl-n-butyl, 1-ethyl-n-butyl, 2-ethyl-n-butyl, 1,1,2-trimethyl-n-propyl, 1,2,2-trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl, 1-ethyl-2-methyl-n-propyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl, etc.

[0058] Specific examples of acetyls with 1 to 10 carbon atoms include methacryl, acetyl, propacryl, butyl, isobutyl, pentyl, isopentyl, hexyl, isohexyl, heptayl, isohexyl, octayl, isooctyl, nonayl, isonayl, decyl, isodecayl, and benzoyl.

[0059] Specific examples of organic solvents represented by the above formulas (S1) to (S7) are as follows: Formula (S1): 3-methoxy-N,N-dimethylpropionic acid, 3-ethoxy-N,N-dimethylpropionic acid, 3-propoxy-N,N-dimethylpropionic acid, 3-isopropoxy-N,N-dimethylpropionic acid, 3-butoxy-N,N-dimethylpropionic acid, 3-dibutoxy-N,N-dimethylpropionic acid, 3-tert-butoxy-N,N-dimethylpropionic acid Formula (S2): 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone Formula (S3): N,N-dimethylmethionic acid, N,N-dimethylacetylamine, N,N-dimethylpropionic acid N,N-Dimethylbutyramine (S4): γ-Butyrolactone (S5): Cyclopentanone, Cyclohexanone, Cycloheptanone (S6): Methyl lactate, Ethyl lactate, Propyl lactate, Butyl lactate, Isoamyl lactate, Methyl 2-hydroxyisobutyrate, Ethyl 2-hydroxyisobutyrate, Propyl 2-hydroxyisobutyrate, Butyl 2-hydroxyisobutyrate (S7): Ethyl cellolytic, Butyl cellolytic, Ethyl glycol, 1-Methoxy-2-propanol, 1-Ethoxy-2-propanol, 1-Butoxy-2-propanol, Propylene glycol monomethyl ether, Propylene glycol-1-monomethyl ether-2-acetate, Propylene glycol-1-monoethyl ether-2-acetate

[0060] In this invention, the preferred organic solvents are N-methyl-2-pyrrolidone, butyl cellolytic agent, propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate; more preferably, propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate; and even more preferably, propylene glycol monomethyl ether. One of these organic solvents may be used alone, or two or more may be used in combination.

[0061] Furthermore, the solvent can be used alone as long as it is within the range that prevents polyacrylic acid from precipitating, and can be mixed into the composition for forming the release layer of the present invention. In particular, solvents with low surface tension such as ethyl cellolytic, butyl cellolytic, 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-ethoxypropoxy)propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, and isoamyl lactate can be mixed in. Therefore, it is known that the uniformity of the coating film during substrate coating is improved, and it is also more suitable for the composition for forming the release layer of the present invention.

[0062] The polyacrylic acid concentration in the composition for forming the release layer of the present invention is appropriately set considering the thickness of the release layer to be produced, the viscosity of the composition, etc., and is usually about 1 to 30% by mass, preferably about 1 to 20% by mass. By setting such a concentration, a release layer with a thickness of about 0.05 to 5 μm can be obtained with good reproducibility. Furthermore, the polyacrylic acid concentration can be adjusted by adjusting the amount of diamine and tetracarboxylic dianhydride used as raw materials for polyacrylic acid, diluting or concentrating the filtrate after filtering the above reaction solution, and adjusting the amount of isolated polyacrylic acid when dissolving it in a solvent.

[0063] Furthermore, the viscosity of the composition used for forming the release layer is appropriately set considering the thickness of the release layer to be produced. However, especially when the goal is to obtain a film with a thickness of approximately 0.05 to 5 μm with good reproducibility, it is typically around 10 to 10,000 mPa·s at 25°C, and preferably around 20 to 5,000 mPa·s. Here, the viscosity can be measured using a commercially available liquid viscosity meter, following the procedure described in, for example, JIS K7117-2, at a temperature of 25°C for the composition. Preferably, a cone plate type rotational viscometer is used, preferably a similar type of viscometer using a 1°34' × R24 standard conical rotor, at a temperature of 25°C for the composition. An example of such a rotational viscometer is the TVE-25L manufactured by Toki Sangyo Co., Ltd.

[0064] Furthermore, in addition to polyamide and organic solvent, the composition for forming the release layer of the present invention may also include components such as crosslinking agents to improve, for example, film strength.

[0065] The release layer forming composition of the present invention described above is coated onto a substrate, and the resulting coating is heated to thermally imidize polyamide, thereby obtaining a release layer made of polyamide film that has excellent adhesion to the substrate and moderate adhesion and release properties to the resin substrate.

[0066] When the release layer of the present invention is formed on a substrate, the release layer may be formed on a portion of the surface of the substrate or on the entire surface. As for the form of the release layer being formed on a portion of the surface of the substrate, there are forms where the release layer is formed only in a specific area of ​​the substrate surface, and forms the release layer on the entire surface of the substrate in the form of patterns such as dot patterns, lines, and spacing patterns. Furthermore, in the present invention, the term "substrate on which the release layer forming composition of the present invention can be coated" refers to a user in the manufacture of flexible electronic devices, etc.

[0067] Examples of substrates include glass, plastics (polycarbonate, polymethyl methacrylate, polystyrene, polyester, polyolefin, epoxy resin, melamine, triacetyl cellulose, ABS, AS, norbornene resin, etc.), metals (silicon wafers, etc.), wood, paper, cement board, etc., but glass is particularly preferred because the release layer obtained from the release layer forming composition of the present invention has sufficient adhesion to it. Furthermore, the substrate surface can be composed of a single material or two or more materials. Examples of substrate surfaces composed of two or more materials include those where a certain area of ​​the substrate surface is composed of one material and the remaining surface is composed of other materials, and those where one material exists as a dot pattern, line pattern, or spacing pattern on the entire surface of the substrate within other materials.

[0068] The coating method is not particularly limited, but examples include casting coating, spin coating, scraper coating, dip coating, roller coating, rod coating, die coating, inkjet coating, and printing methods (letterpress, gravure, offset, screen printing, etc.).

[0069] The heating temperature used for amide imidization is typically determined appropriately within the range of 50 to 550°C, but preferably above 200°C and more preferably below 500°C. By setting the heating temperature in this way, the fragility of the resulting film can be prevented and the amide imidization reaction can be carried out sufficiently. The heating time varies with the heating temperature and cannot be specified in general, but it is usually from 5 minutes to 5 hours. And the amide imidization rate only needs to be in the range of 50% to 100%.

[0070] As a preferred example of the heating state of the present invention, an example is a method in which the heating temperature is directly and gradually increased after heating at 50~170°C for 1 minute to 2 hours, and finally heated at 180~450°C for 30 minutes to 4 hours. Particularly preferred is heating at 50~150°C for 1 minute to 2 hours, and then heating at 220~300°C for 5 minutes to 2 hours.

[0071] Examples of heating appliances include, for example, heating plates and ovens. The heating environment can be air or an inert gas environment, and can be at normal pressure or under reduced pressure.

[0072] The thickness of the release layer is usually around 0.01~50μm. From a production point of view, it is preferably around 0.05~20μm, and even more preferably around 0.05~5μm. The desired thickness can be achieved by adjusting the coating thickness before heating.

[0073] The release layer described above has excellent adhesion to the substrate, especially to the glass substrate, and moderate adhesion and release properties to the resin substrate. Therefore, in the manufacturing process of flexible electronic devices, the release layer of the present invention can be used more appropriately without damaging the resin substrate of the device, and the resin substrate and the circuits formed on the resin substrate can be peeled off from the substrate together.

[0074] The following describes an example of a method for manufacturing a flexible electronic device using the release layer of the present invention. Using the release layer forming composition of the present invention, a release layer is formed on a glass substrate by the aforementioned method. A resin solution for forming a resin substrate is coated onto the release layer, and the coating is heated to form a resin substrate fixed to the glass substrate by the release layer of the present invention. At this time, the resin substrate is formed with an area larger than the area of ​​the release layer, completely covering the release layer. Examples of the resin substrate include resin substrates made of representative polyimide resins, acrylic resins, or cyclic olefin polymer resins, which are resin substrates for flexible electronic devices. Examples of resin solutions used to form such substrates include polyimide solutions, polyacrylic acid solutions, acrylic polymer solutions, and cyclic olefin polymer solutions. The method for forming this resin substrate can be any commonly used method. Furthermore, as a resin substrate with high transparency, examples include resin substrates formed of polyimide resin, acrylic resin or cyclic olefin polymer resin, and those with a light transmittance of 80% or more at a wavelength of 450nm are particularly preferred.

[0075] Next, on the resin substrate fixed to the substrate by the release layer of the present invention, a desired circuit is formed as needed. Then, for example, the resin substrate is cut along the release layer, and the resin substrate and the circuit are peeled off from the release layer together, thus separating the resin substrate from the substrate. At this time, a portion of the substrate can also be cut together with the release layer.

[0076] In this invention, the peeling force when peeling the resin substrate from the substrate is preferably not more than 0.5 N / 25 mm, more preferably not more than 0.4 N / 25 mm, and even more preferably not more than 0.3 N / 25 mm, based on the viewpoint that the resin substrate can be easily peeled from the substrate in the end. On the other hand, the lower limit of the above peeling force is not particularly limited, but based on the viewpoint of stably fixing the resin substrate to the substrate and stably manufacturing electronic devices, it is preferably 0.001 N / 25 mm or more, more preferably 0.01 N / 25 mm or more, and even more preferably 0.02 N / 25 mm or more.

[0077] The release layer of the present invention maintains the peeling force of the resin substrate peeling off from the substrate within the aforementioned range even when the resin substrate formed thereon is fired at a temperature of Tg or higher. For example, when a resin substrate with a Tg of 200°C or lower is formed on a release layer formed using the release layer forming composition of the present invention, and fired at a temperature of 230°C or higher, the resin substrate can preferably be peeled off with a peeling force within the aforementioned range.

[0078] On the other hand, it has been reported that in the manufacture of flexible displays, the laser ablation method (LLO method), which is used in the manufacture of high-brightness LEDs or three-dimensional semiconductor packages to date, can appropriately peel off the polymer substrate from the glass carrier (Japanese Patent Application Publication No. 2013-147599). The manufacture of flexible displays requires the provision of a polymer substrate formed of polyimide or the like on a glass carrier, followed by the formation of circuits including electrodes on the substrate, and finally the peeling of the substrate and the circuits together from the glass carrier. In this peeling step, the LLO method is used, that is, when light with a wavelength of 308 nm is irradiated onto the glass carrier from the side opposite to where the circuits are formed, the light of that wavelength passes through the glass carrier, and only the polymer (polyimide) near the glass carrier absorbs the light and evaporates (sublimates). It has been reported that this does not affect the circuits on the substrate that determine the performance of the display, and the peeling of the substrate from the glass carrier can be selectively performed.

[0079] When a desired circuit is formed on a resin substrate fixed to a substrate by the release layer of the present invention, and subsequently, if the LLO method is used, only the release layer absorbs the light and evaporates (sublimates). That is, the release layer becomes a sacrifice (acts as a sacrificial layer), and selectively performs the release of the substrate from the glass carrier. The composition for forming the release layer of the present invention has the characteristic of sufficiently absorbing light of a specific wavelength (e.g., 308 nm) applicable to the LLO method, and therefore can be used as a sacrificial layer in the LLO method. [Example]

[0080] The following examples illustrate the present invention in more detail, but the present invention is not limited to these examples. Furthermore, the abbreviations of the compounds used in the following examples and the methods for determining the number-average molecular weight and weight-average molecular weight are as follows.

[0081] <Abbreviations of Compounds> p-PDA: p-phenylenediamine; DA-4P: 1,3-bis(4-aminophenoxy)benzene; DA-4: 1,4-bis(4-aminophenoxy)benzene; DDE: 4,4'-oxydiphenylamine; 3,4'-DDE: 3,4'-diaminodiphenyl ether; 3,3'-DDE: 3,3'-diaminodiphenyl ether; DA-3F: 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane; BTFDPE: 2,2'-trifluoromethyl-4,4'-diaminodiphenyl ether; BPDA: 3,3',4,4'-biphenyltetracarboxylic acid dianhydride; PDMA: pyromellitic dianhydride; TAHQ: p-Phenylbis(trimethoxymethyl ester anhydride); BPTME: p-Biphenylbis(trimethoxymethyl ester anhydride) ODPA: 4,4'-oxyphthalic anhydride; NMP: N-methyl-2-pyrrolidone; BCS: butylated cellulosin.

[0082] <Determination of Number Average Molecular Weight and Weight Average Molecular Weight> The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polymer were determined using a GPC apparatus manufactured by Nippon Spectrophotometer (columns: Shodex KD801 and KD805; dissolution solution: dimethylformamide / LiBr·H2O (29.6mM) / H3PO4 (29.6mM) / THF (0.1 mass%); flow rate: 1.0 mL / min; column temperature: 40°C; Mw: conversion value of standard polystyrene) (the same applies to the following examples and comparative examples).

[0083] [1] Polyamide is synthesized by the following method. Furthermore, instead of isolating the polymer from the obtained reaction solution containing the polymer, as described later, a composition for forming a resin substrate or a composition for forming a release layer is prepared by diluting the reaction solution.

[0084] [Synthesis Example 1] Synthesis of Polyacrylic Acid L1: 214.9 g (0.74 mmol) of DA-4P was dissolved in 4,400 g of NMP. 385.1 g (0.72 mmol) of BPTME was added to the resulting solution, and the mixture was reacted at 23 °C for 24 hours under nitrogen atmosphere to obtain polyacrylic acid L1. The Mw of polyacrylic acid L1 was 50,700, and the Mw / Mn ratio was 2.51.

[0085] [Synthesis Example 2] Synthesis of Polyacrylic Acid L2: 214.9 g (0.74 mmol) of DA-4 was dissolved in 4,400 g of NMP. 385.1 g (0.72 mmol) of BPTME was added to the resulting solution, and the reaction was carried out at 23 °C for 24 hours under nitrogen atmosphere to obtain polyacrylic acid L2. The Mw of polyacrylic acid L2 was 56,400, and the Mw / Mn ratio was 2.6.

[0086] [Synthesis Example 3] Synthesis of Polyacrylic Acid L3: 165.9 g (0.83 mmol) of DDE was dissolved in 4,400 g of NMP. 434.1 g (0.81 mmol) of BPTME was added to the resulting solution, and the reaction was carried out at 23 °C for 24 hours under nitrogen atmosphere to obtain polyacrylic acid L3. The Mw of polyacrylic acid L3 was 48,300, and the Mw / Mn ratio was 2.6.

[0087] [Synthesis Example 4] Synthesis of Polyacrylic Acid L4: 165.9 g (0.83 mmol) of 3,4'-DDE was dissolved in 4,400 g of NMP. 434.1 g (0.81 mmol) of BPTME was added to the resulting solution, and the reaction was carried out at 23 °C for 24 hours under nitrogen atmosphere to obtain polyacrylic acid L4. The Mw of polyacrylic acid L4 was 31,000, and the Mw / Mn ratio was 2.4.

[0088] [Synthesis Example 5] Synthesis of Polyacrylic Acid L5: 165.9 g (0.83 mmol) of 3,3'-DDE was dissolved in 4,400 g of NMP. 434.1 g (0.81 mmol) of BPTME was added to the resulting solution, and the reaction was carried out at 23 °C for 24 hours under nitrogen atmosphere to obtain polyacrylic acid L5. The Mw of polyacrylic acid L5 was 25,300, and the Mw / Mn ratio was 2.3.

[0089] [Comparative Synthesis Example 1] Synthesis of Polyacrylic Acid HL1: 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 resulting solution, and the reaction was carried out at 23 °C for 24 hours under nitrogen atmosphere to obtain polyacrylic acid HL1. The Mw of polyacrylic acid HL1 was 107,300, and the Mw / Mn ratio was 4.6.

[0090] [Comparative Synthesis Example 2] Synthesis of Polyacrylic Acid HL2: 0.931 g (8.6 mmol) of p-PDA was dissolved in 35.2 g of NMP. 3.868 g (8.4 mmol) of TAHQ was added to the resulting solution, and the reaction was carried out at 23°C for 24 hours under nitrogen atmosphere to obtain polyacrylic acid HL2. The Mw of polyacrylic acid HL2 was 45,000, and the Mw / Mn ratio was 2.7.

[0091] [Comparative Synthesis Example 3] Synthesis of Polyacrylic Acid HL3: 2.984 g (5.6 mmol) of DA-3F was dissolved in 35.2 g of NMP. 3.015 g (5.8 mmol) of BPTME was added to the resulting solution, and the reaction was carried out at 23 °C for 24 hours under nitrogen atmosphere to obtain polyacrylic acid HL3. The Mw of polyacrylic acid HL3 was 45,000, and the Mw / Mn ratio was 2.7.

[0092] [Comparative Synthesis Example 4] Synthesis of Polyacrylic Acid HL4: 5.55 g (51 mmol) of p-PDA was dissolved in 132 g of NMP. 12.45 g (57 mmol) of PMDA was added to the resulting solution, and the mixture was reacted at 23 °C for 24 hours under nitrogen atmosphere to obtain polyacrylic acid HL3. The Mw of polyacrylic acid HL3 was 76,400, and the Mw / Mn ratio was 2.2.

[0093] [Comparative Synthesis Example 5] Synthesis of Polyacrylic Acid HL5: 0.253 g (0.70 mmol) of BTFDPE was dissolved in 4.4 g of NMP. 0.365 g (0.68 mmol) of BPTME was added to the resulting solution, and the mixture was reacted at 23°C for 24 hours under nitrogen atmosphere to obtain polyacrylic acid HL5. The Mw of polyacrylic acid HL5 was 42,600, and the Mw / Mn ratio was 2.6.

[0094] [Synthesis Example F1] Synthesis of Polyacrylic Acid F1: 392.1 g (1.3 mol) of DA-4P was dissolved in 3,200 g of NMP. 407.8 g (1.3 mol) of ODPA was added to the resulting solution, and the reaction was carried out at 23°C for 24 hours under nitrogen atmosphere to obtain polyacrylic acid F1. The Mw of polyacrylic acid F1 was 60,400, and the Mw / Mn ratio was 2.9.

[0095] [2] Preparation of the composition for forming resin substrate The reaction solution obtained from Synthesis Example F1 was directly used as the composition for forming resin substrate.

[0096] [3] Preparation of composition for stripper layer formation [Example 1-1] BCS and NMP were added to the reaction solution obtained in Synthesis Example 1 and diluted to a polymer concentration of 5% by mass and a BCS concentration of 20% by mass to obtain a composition for stripper layer formation.

[0097] [Examples 1-2~1-5] Except for replacing the reaction solution obtained in Synthesis Example 1, the reaction solutions obtained in Synthesis Examples 2 to 5 were used respectively to obtain the composition for forming the release agent layer in the same manner as in Example 1-1.

[0098] [Comparative Examples 1-1 to 1-5] Except for replacing the reaction solution obtained in Synthesis Example 1, the reaction solutions obtained in Comparative Examples 1 to 5 were used respectively to obtain the composition for forming the release agent layer in the same manner as in Example 1-1.

[0099] [4] Formation of release agent [Example 2-1] Using a spin coater (conditions: rotation speed 3,000 rpm for about 30 seconds), the release agent layer forming composition obtained in Example 1-1 was applied to a 100mm × 100mm glass substrate (hereinafter the same) as a glass substrate. Then, the resulting coating was heated at 80°C for 10 minutes using a heating plate, and then heated at 230°C for 30 minutes using an oven to form a release layer of about 0.1μm thickness on the glass substrate, thereby obtaining a glass substrate with a release layer. Furthermore, during the heating period, the glass substrate with the release layer was not removed from the oven, but was heated inside the oven.

[0100] [Examples 2-2~2-5] Except for replacing the release agent layer composition obtained in Example 1-1, the release agent layer composition obtained in Examples 1-2~1-5 was used respectively to form a release layer in the same way as in Example 2-1, and a glass substrate with a release layer was obtained.

[0101] [Comparative Examples 2-1 to 2-5] Except for replacing the release agent layer composition obtained in Example 1-1, the release agent layer composition obtained in Comparative Examples 1-1 to 1-5 was used to form the release layer in the same manner as in Example 2-1, and a glass substrate with a release layer was obtained.

[0102] [5] Formation and evaluation of the release properties of the resin substrate [Example 3-1] Using a bar coater (gap: 250 μm), a resin substrate forming composition was coated onto the release layer (resin film) of the glass substrate with the release layer obtained in Example 2-1. Then, the resulting coating was heated at 100°C for 30 minutes using a heating plate, and then heated at 230°C for 60 minutes using an oven to form a polyimide substrate with a thickness of about 20 μm on the release layer.

[0103] [Examples 3-2~3-5, Comparative Examples 3-1~3-5] Except for replacing the glass substrate with release layer obtained in Example 2-1, the glass substrate with release layer obtained in Examples 2-2~2-5 and Comparative Examples 2-1~2-5 were used respectively, and a polyimide substrate was formed on the release layer in the same way as in Example 3-1.

[0104] [Examples 3-6] Using a bar coater (gap: 250 μm), a resin substrate forming composition was coated onto the release layer (resin film) of the glass substrate with the release layer obtained in Examples 2-2. Next, the resulting coating was heated at 100°C for 30 minutes using a heating plate, followed by heating at 300°C for 60 minutes using an oven, forming a polyimide substrate with a thickness of approximately 20 μm on the release layer.

[0105] [Examples 3-7, 3-8] Except for replacing the glass substrate with a release layer obtained in Example 2-2, the glass substrate with a release layer obtained in Examples 2-4 to 2-5 was used respectively, and a polyimide substrate was formed on the release layer in the same way as in Example 3-6.

[0106] <Evaluation of Peel Force of Resin Substrate> (1) Peel force of resin substrate before heat treatment The resin substrates formed in Examples 3-1 to 3-8 and Comparative Examples 3-1 to 3-5 were cut into short strips 25 mm wide using a cutter. Then, glass tape SELLOTAPE (registered trademark) was attached to the front end of the cut resin substrate and used as a test piece. The test piece was peeled using a push-pull tester manufactured by ATTONIC at a peel angle of 90°, and the peel force was evaluated based on the following criteria. In addition, the peel surface was confirmed by an optical microscope, and the peel layer was recorded as defective when it was in contact with the glass substrate. The results are shown in Table 1. The Tg of the peeled resin substrate was measured by TMA-4000SA (manufactured by BRUKER AXS) and was about 190°. Furthermore, the light transmittance was measured using a UV-Vis spectrophotometer (Shimadzu Corporation UV-2600), and the resin substrate showed a transmittance of over 80% at 450nm.

[0107] Defect: Confirmed separation of the release layer from the glass substrate. 4b: Not peeled; 3b: Peel force ≥ 1.00 N / 25 mm; 2b: Peel force ≥ 0.80 N / 25 mm but less than 1.00 N / 25 mm; 1b: Peel force ≥ 0.60 N / 25 mm but less than 0.80 N / 25 mm; b: Peel force ≥ 0.50 N / 25 mm but less than 0.60 N / 25 mm; a: Peel force ≥ 0.40 N / 25 mm but less than 0.50 N / 25 mm; aa: Peel force ≥ 0.30 N / 25 mm but less than 0.40 N / 25 mm; aaa: Peel force less than 0.30 N / 25 mm.

[0108] (2) Peel strength of resin substrates after heat treatment The resin substrates formed in Examples 3-1 to 3-8 were fixed to the glass substrate and heated in an oven at the temperatures shown in Table 1 for 2 hours. The peel strength of the resin substrates after heat treatment was evaluated in the same way as in (1) above. The results are shown in Table 1. Also, regarding the resin substrates of Comparative Examples 3-1 to 3-5, since they were closely adhered to the release layer before heat treatment and could not be peeled off from the release layer, the peel strength after heat treatment was not evaluated.

[0109]

[0110] The results in Table 1 confirm that the release layer of the embodiment not only has excellent adhesion to the substrate and moderate adhesion and moderate release properties to the resin substrate, but also maintains moderate release properties even when the resin substrate is fired at a temperature above Tg without adhering closely to the resin substrate.

Claims

1. A laminate comprising: a glass substrate, a release layer formed on the glass substrate, and a resin substrate formed on the release layer, wherein the release layer is obtained using a release layer forming composition comprising polyamide represented by the following formula (1) and an organic solvent.

1. (In the formula, X is an aromatic group represented by the following formula (X1), Y is a divalent organic group containing any of the aromatic groups represented by the following formulas (Y9) to (Y13) and without fluorine atoms, and n represents a natural number) 2. The laminate as claimed in claim 1, wherein the organic solvent is selected from at least one having a structure represented by the following formulas (S1) to (S7).

2. (In the formula, R1s~R8s independently represent hydrogen atoms or alkyl groups with 1~10 carbon atoms, R9s and R10s independently represent hydrogen atoms, alkyl groups with 1~10 carbon atoms or acetyl groups with 1~10 carbon atoms, and b and m represent natural numbers).

3. A method for manufacturing a resin substrate, wherein the resin substrate is separated from the release layer using a laminate as claimed in claim 1 or 2.

4. The manufacturing method of claim 3, wherein the resin substrate is a polyimide substrate.