WO2018105674A1

WO2018105674A1 - Release layer production method

Info

Publication number: WO2018105674A1
Application number: PCT/JP2017/043907
Authority: WO
Inventors: 江原　和也
Original assignee: 日産化学工業株式会社
Priority date: 2016-12-08
Filing date: 2017-12-07
Publication date: 2018-06-14
Also published as: JP6897690B2; CN110049827A; TW201829668A; JPWO2018105674A1; TWI823841B; KR102439472B1; KR20190094197A

Abstract

A release layer production method is provided which involves a step for coating a substrate with a release layer forming composition and firing at a maximum temperature of no less than 400°C, wherein the release layer forming composition contains an organic solvent, and a polyamic acid having both ends derived from a tetracarboxylic acid, with either one or both of said ends sealed with 2-aminophenol.

Description

Method for producing release layer

The present invention relates to a method for producing a release layer.

In recent years, electronic devices have been required to have a function of being able to bend in addition to the characteristics of thinning and lightening. For this reason, it is required to use a lightweight flexible plastic substrate in place of the conventional glass substrate that is fragile and cannot be bent.
In particular, in the new generation display, development of an active matrix type full color TFT display panel using a lightweight flexible plastic substrate (hereinafter referred to as a resin substrate) is required. This new generation display technology is expected to be diverted to various fields such as flexible displays, flexible smartphones, and mirror displays.

Therefore, various methods for manufacturing electronic devices using a resin film as a substrate are being studied, and in the new generation display, a process for diverting existing facilities for manufacturing TFT display panels is being investigated.

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

In Patent Document 4, a layer to be peeled (described as “transfer target layer” in Patent Document 4) is attached to a plastic film by using the techniques disclosed in Patent Documents 1 to 3, and a liquid crystal display device is formed. A method of completion 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 highly light-transmitting substrate in order to transmit laser light, and the substrate passes through the substrate. In addition, it is necessary to irradiate laser light with a relatively large energy sufficient to release hydrogen contained in amorphous silicon, and the layer to be peeled may be damaged by the laser light irradiation. There is a problem.
In addition, when the layer to be peeled has a large area, it takes a long time for the laser treatment, and it is difficult to increase the productivity of device fabrication.

JP 10-125929 A Japanese Patent Laid-Open No. 10-125931 International Publication No. 2005/050754 JP-A-10-125930

This invention is made | formed in view of the said situation, and it aims at providing the manufacturing method of the peeling layer which can peel without damaging the resin substrate of a flexible electronic device.

As a result of intensive studies to solve the above problems, the present inventor has obtained a composition comprising a polyamic acid in which one or both of the tetracarboxylic acid ends are sealed with 2-aminophenol, and an organic solvent. With the firing temperature at the time of forming the release layer being equal to or higher than the predetermined maximum temperature, excellent adhesion to the substrate and appropriate adhesion to the resin substrate used in the flexible electronic device and appropriate release properties are achieved. The present invention has been completed by finding that a release layer can be formed.

That is, the present invention
1. A release layer-forming composition comprising a polyamic acid having both ends derived from tetracarboxylic acid and one or both of both ends sealed with 2-aminophenol and an organic solvent is formed on a substrate. A method for producing a release layer, comprising a step of applying and baking at a maximum temperature of 400 ° C. or higher,
2. The method for producing a release layer according to claim 1, wherein the polyamic acid is a polyamic acid obtained by reacting a diamine component containing an aromatic diamine with an acid dianhydride component containing an aromatic tetracarboxylic dianhydride,
3. A method for producing a release layer of 2, wherein the aromatic diamine is an aromatic diamine containing 1 to 5 benzene nuclei,
4). A method for producing a release layer of 2 or 3, wherein the aromatic tetracarboxylic dianhydride is an aromatic tetracarboxylic dianhydride containing 1 to 5 benzene nuclei,
5). A method for producing a flexible electronic device comprising a resin substrate, characterized by using a release layer formed by using any one of production methods 1 to 4;
6). A flexible electronic device comprising a step of applying a composition for forming a resin substrate on a release layer formed by using any one of production methods 1 to 4 and then firing the resin substrate at a maximum temperature of 450 ° C. to form a resin substrate Manufacturing method,
7). The method for producing a flexible electronic device according to 5 or 6, wherein the resin substrate is a polyimide resin substrate.

By adopting the method for producing a release layer of the present invention, it is possible to obtain a release layer having excellent adhesion to a substrate, moderate adhesion to a resin substrate, and moderate release with good reproducibility. Therefore, by implementing the manufacturing method of the present invention, in the manufacturing process of the flexible electronic device, the circuit or the like without damaging the resin substrate formed on the substrate or the circuit provided on the substrate. At the same time, the resin substrate can be separated from the substrate. Therefore, the manufacturing method of this invention can contribute to the simplification of the manufacturing process of a flexible electronic device provided with a resin substrate, the yield improvement, etc.

Hereinafter, the present invention will be described in more detail.
The method for producing a release layer according to the present invention comprises a polyamic acid having both ends derived from tetracarboxylic acid, one or both of which are sealed with 2-aminophenol, and an organic solvent. The method further comprises a step of applying the release layer-forming composition to the substrate and baking at a maximum temperature of 400 ° C. or higher.
Here, the release layer in the present invention is a layer provided immediately above a glass substrate for a predetermined purpose. As a typical example, in a manufacturing process of a flexible electronic device, a flexible electronic made of a substrate and a resin such as polyimide is used. Provided between the device resin substrate and the resin substrate in a predetermined process, and after the electronic circuit or the like is formed on the resin substrate, the resin substrate can be easily peeled from the substrate. For example, a release layer may be used.

The polyamic acid used in the present invention is obtained by reacting and sealing one or both of the polymer chain ends of polyamic acid having both ends derived from tetracarboxylic acid with the amino group of 2-aminophenol. Can do. That is, in the polyamic acid obtained here, one or both of the molecular chain ends are sealed with a hydroxy group-containing phenyl group.

Since the polymer terminal has a hydroxy group, the skeleton can be different from the flexible substrate used for the upper layer, so that the function of the resulting film as a release layer can be improved.

In the present invention, a hydroxy group derived from 2-aminophenol may be present at either one of the polymer chain ends of the polyamic acid, but a hydroxy group derived from 2-aminophenol is present at both of the polymer chain ends. Preferably it is present.

Moreover, as a diamine component and an acid dianhydride component used when producing a polyamic acid, from the viewpoint of improving the function as a release layer of the obtained film, a diamine component containing an aromatic diamine and an aromatic tetracarboxylic acid dicarboxylic acid are used. A polyamic acid obtained by reacting an acid dianhydride component containing an anhydride is preferred.

The aromatic diamine is not particularly limited as long as it has two amino groups in the molecule and has an aromatic ring, but an aromatic diamine containing 1 to 5 benzene nuclei is preferable.
Specific examples thereof include 1,4-diaminobenzene (p-phenylenediamine), 1,3-diaminobenzene (m-phenylenediamine), 1,2-diaminobenzene (o-phenylenediamine), 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, 3,5-bis (trifluoromethyl A diamine having one benzene nucleus such as benzene-1,2-diamine; 1,2-naphthalenediamine, 1,3-naphthalenediamine, 1,4-naphthalenediamine, 1,5-naphthalenediamine, 1,6-naphthalenediamine 1,7-naphthalenediamine, 1,8-naphthalenediamine, 2,3-naphthalenediamine, 2,6-naphthalenediamine, 4,4′-biphenyldiamine, 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'-dimethylbenz 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, 4,4′-diaminoocta Benzene nuclei having two diamines such as luorobiphenyl, 2- (3-aminophenyl) -5-aminobenzimidazole, 2- (4-aminophenyl) -5-aminobenzoxazole; 1,5-diaminoanthracene, 2,6-diaminoanthracene, 9,10-diaminoanthracene, 1,8-diaminophenanthrene, 2,7-diaminophenanthrene, 3,6-diaminophenanthrene, 9,10-diaminophenanthrene, 1,3-bis (3- Aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1,4-bis (3-aminophenyl) benzene, 1,4-bis (4-aminophenyl) benzene, 1,3-bis ( 3-aminophenylsulfide) benzene, 1,3-bis (4-aminophenylsulfide) benze 1,4-bis (4-aminophenylsulfide) benzene, 1,3-bis (3-aminophenylsulfone) benzene, 1,3-bis (4-aminophenylsulfone) benzene, 1,4-bis (4 -Aminophenylsulfone) benzene, 1,3-bis [2- (4-aminophenyl) isopropyl] benzene, 1,4-bis [2- (3-aminophenyl) isopropyl] benzene, 1,4-bis [2 -(4-Aminophenyl) isopropyl] benzene, 4,4 ″ -diamino-p-terphenyl, 4,4 ″ -diamino-m-terphenyl and the like, and benzene nuclei having three diamines can be mentioned. However, it is not limited to these. These can be used alone or in combination of two or more. In the present invention, the aromatic diamine preferably does not contain an ether bond or an ester bond.

Among them, from the viewpoint of improving the function of the resulting film as a release layer, an aromatic ring and an aromatic ring composed only of an aromatic ring having no substituent such as a methyl group and a heteroaromatic ring on the heterocyclic ring condensed thereto. Group diamines are preferred. Specifically, p-phenylenediamine, m-phenylenediamine, 2- (3-aminophenyl) -5-aminobenzimidazole, 2- (4-aminophenyl) -5-aminobenzooxol, 4,4 ′ '-Diamino-p-terphenyl and the like are preferred.

The aromatic tetracarboxylic dianhydride is not particularly limited as long as it has two dicarboxylic anhydride sites in the molecule and has an aromatic ring, but an aromatic tetracarboxylic dianhydride contains 1 to 5 benzene nuclei. Group tetracarboxylic dianhydrides are preferred.

Specific examples thereof 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-2,3,3', 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 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 Although an anhydride etc. can be mentioned, it is not limited to these. These can be used alone or in combination of two or more.

Of these, aromatic carboxylic dianhydrides having one or two benzene nuclei are preferred from the viewpoint of improving the function of the resulting film as a release layer. Specifically, an aromatic tetracarboxylic dianhydride represented by any one of formulas (C1) to (C12) is preferred, and any one of formulas (C1) to (C7) and (C9) to (C11) The aromatic tetracarboxylic dianhydride shown is more preferred.

In addition, from the viewpoint of improving the flexibility, heat resistance, etc. of the resulting release layer, the diamine component used in the present invention may contain a diamine other than an aromatic diamine, and the tetracarboxylic dianhydride component used in the present invention is Further, tetracarboxylic dianhydrides other than aromatic tetracarboxylic dianhydrides may be included.

In the present invention, the amount of aromatic diamine in the diamine component is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and most preferably 100 mol%. The amount of aromatic tetracarboxylic dianhydride in the tetracarboxylic acid component is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and still more preferably 95 mol%. Above, most preferably 100 mol%. By adopting such a use amount, it is possible to obtain a film having excellent adhesion to the substrate, moderate adhesion to the resin substrate, and moderate peelability with good reproducibility.

After reacting the diamine component and the tetracarboxylic dianhydride component described above, the resulting polyamic acid and 2-aminophenol are reacted to be included in the composition for forming a release layer of the present invention. A polyamic acid in which the polymer chain ends are sealed with 2-aminophenol can be obtained.

The charging ratio of the diamine component and the tetracarboxylic dianhydride component is appropriately determined in consideration of the target molecular weight and molecular weight distribution, the type of diamine and the type of tetracarboxylic dianhydride, etc. In order to obtain both ends of the molecular chain derived from tetracarboxylic acid, it is preferable to increase the number of moles of the tetracarboxylic dianhydride component relative to the number of moles of the diamine component. Specifically, the molar ratio of the tetracarboxylic dianhydride component is preferably 1.02 to 3.0 mol, more preferably 1.07 to 2.5 mol, with respect to 1 mol of the diamine component. 2.0 mol is even more preferable.

The organic solvent used for synthesizing the polyamic acid and sealing the molecular chain end of the synthesized polyamic acid is not particularly limited as long as it does not adversely affect the reaction. Specific examples thereof include m-cresol, 2-pyrrolidone, N— Methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, 3-methoxy-N, N-dimethylpropylamide, 3- Ethoxy-N, N-dimethylpropylamide, 3-propoxy-N, N-dimethylpropylamide, 3-isopropoxy-N, N-dimethylpropylamide, 3-butoxy-N, N-dimethylpropylamide, 3-sec -Butoxy-N, N-dimethylpropylamide, 3-tert-butoxy-N, N-dimethyl Propyl amide, .gamma.-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, amides represented by formula (S1), amides represented by formula (S2) and formula ( At least one selected from amides represented by S3) is preferred.

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, preferably 1 to 3, more preferably 1 or 2.

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

The reaction temperature during the synthesis of the polyamic acid may be appropriately set in the range from the melting point to the boiling point of the solvent to be used, and is usually about 0 to 100 ° C. However, it prevents imidization of the resulting polyamic acid in the solution. From the viewpoint of maintaining a high content of polyamic acid units, the temperature can be preferably about 0 to 70 ° C, more preferably about 0 to 60 ° C, and still more preferably about 0 to 50 ° C. Although the reaction time depends on the reaction temperature and the reactivity of the raw material, it cannot be defined unconditionally, but is usually about 1 to 100 hours.

The reaction temperature at the time of sealing the molecular chain end of the polyamic acid may be appropriately set in the range from the melting point to the boiling point of the solvent used, as in the synthesis of the polyamic acid, and is usually about 0 to 100 ° C. From the viewpoint of securely sealing the molecular chain terminal of the synthesized polyamic acid, the temperature can be preferably about 0 to 70 ° C, more preferably about 0 to 60 ° C, and still more preferably about 0 to 50 ° C. Although the reaction time depends on the reaction temperature and the reactivity of the raw material, it cannot be defined unconditionally, but is usually about 1 to 100 hours.

The weight average molecular weight of the polyamic acid obtained in this manner and having either or both of the molecular chain ends sealed with 2-aminophenol is usually about 5,000 to 500,000. From the viewpoint of improving the function of the film as a release layer, it is preferably about 6,000 to 200,000, more preferably about 7,000 to 150,000. In addition, in this invention, a weight average molecular weight is a polystyrene conversion value by a gel permeation chromatography (GPC) measurement.

In the present invention, usually, the reaction solution after end-capping can be used as it is, or a solution obtained by diluting or concentrating can be used as the release layer forming composition of the present invention. In addition, you may filter the said reaction solution as needed. By filtering, not only can mixing of impurities that may cause deterioration of the adhesion and peelability of the resulting release layer, but also a composition for forming a release layer can be obtained efficiently. Further, after isolating the polyamic acid from the reaction solution, it may be dissolved again in a solvent to form a release layer forming composition. Examples of the solvent in this case include organic solvents used in the above-described reaction.

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

Further, even if the solvent alone does not dissolve the polyamic acid, it can be mixed with the release layer forming composition 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 A solvent 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. Thereby, it is known that the coating film uniformity is improved upon application to the substrate, and it is also suitably used in the composition for forming a release layer of the present invention.

The concentration of the polyamic acid in the composition for forming a release layer of the present invention is appropriately set in consideration of the thickness of the release layer to be produced, the viscosity of the composition, etc., but is usually about 1 to 30% by mass, preferably It is about 1 to 20% by mass. By setting 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 polyamic acid is adjusted to adjust the amount of diamine and tetracarboxylic dianhydride used as raw materials for polyamic acid, and after filtering the reaction solution, the filtrate is diluted or concentrated, and the isolated polyamic acid is used as a solvent. The amount can be adjusted by, for example, adjusting the amount when dissolved in the aqueous solution.

The viscosity of the release layer-forming composition of the present invention is appropriately set in consideration of the thickness of the release layer to be produced, etc., and in particular, a film having a thickness of about 0.05 to 5 μm can be obtained with good reproducibility. Is usually about 10 to 10,000 mPa · s, preferably about 20 to 5,000 mPa · s at 25 ° C.

Here, the viscosity can be measured using a commercially available liquid viscosity measurement viscometer, for example, with reference to the procedure described in JIS K7117-2 at a temperature of the composition of 25 ° C. . Preferably, a conical plate type (cone plate type) rotational viscometer is used as the viscometer, and preferably the composition temperature is 25 ° C. using 1 ° 34 ′ × R24 as a standard cone rotor. 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 of the present invention may contain a crosslinking agent or the like in order to improve the film strength, for example, in addition to the polyamic acid and the organic solvent.

After the composition for forming a release layer described above is applied on a substrate, the adhesiveness to the substrate is excellent by thermally imidizing polyamic acid by a baking method including a step of baking at a maximum temperature of 400 ° C. or higher. In addition, it is possible to obtain a release layer made of a polyimide film having appropriate adhesion to the resin substrate and appropriate peelability.
In the present invention, the maximum temperature at the time of firing is not particularly limited as long as it is in the range of 400 ° C. or higher and not higher than the heat resistant temperature of polyimide. In view of improving the excellent adhesion and peelability, 450 ° C. or higher is preferable, and 500 ° C. or higher is more preferable. The upper limit is usually about 550 ° C., preferably about 510 ° C. By making heating temperature into the said range, it becomes possible to fully advance an imidation reaction, preventing weakening of the film | membrane obtained.
The heating time varies depending on the heating temperature and cannot be defined generally, but is usually 1 minute to 5 hours. The imidization rate may be in the range of 50 to 100%.

Moreover, as long as the maximum temperature becomes the said range, the temperature at the time of the said baking may include the process baked at the temperature below it.
As a preferred example of the heating mode in the present invention, there is a method of heating at 50 to 150 ° C., then raising the heating temperature stepwise as it is, and finally heating at 400 ° C. or higher. In particular, as a more preferable example of the heating mode, a method of heating at 50 to 100 ° C., heating at a temperature higher than 100 ° C. to less than 400 ° C., and heating at 400 ° C. or higher can be mentioned. Furthermore, as another more preferable example of the heating mode, after heating at 50 to 150 ° C., heating at 150 to 350 ° C., then heating at 350 to 450 ° C., and finally 450 to 510 ° C. A method of heating at 0 ° C. can be mentioned.

In addition, as a preferable example of the heating mode in consideration of the firing time, after heating at 50 to 150 ° C. for 1 minute to 2 hours, the heating temperature is increased stepwise and finally at 400 ° C. or higher for 30 minutes. A method of heating for up to 4 hours can be mentioned. In particular, as a more preferable example of the heating mode, heating is performed at 50 to 100 ° C. for 1 minute to 2 hours, heating is performed above 100 ° C. to less than 400 ° C. for 5 minutes to 2 hours, and heating is performed at 400 ° C. or higher for 30 minutes to 4 hours. The technique to do is mentioned. Further, as another more preferable example of the heating mode, after heating at 50 to 150 ° C. for 1 minute to 2 hours, after exceeding 150 ° C. to 350 ° C. for 5 minutes to 2 hours, then, exceeding 350 ° C. to 450 ° C. for 30 minutes For example, a method of heating at 450 ° C. to 510 ° C. for 30 minutes to 4 hours is mentioned.

In addition, when forming the peeling layer of this invention on a base | substrate, the peeling layer may be formed in the partial surface of a base | substrate, and may be formed in the whole surface. As an aspect of forming a release layer on a part of the surface of the substrate, an embodiment in which the release layer is formed only within a predetermined range of the substrate surface, a 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 are forms to be formed. In addition, in this invention, a base | substrate means what is used for manufacture of a flexible electronic device etc. by which the composition for peeling layer formation of this invention is applied to the surface.

Examples of the substrate (base material) include glass, metal (silicon wafer, etc.), slate, and the like. In particular, glass is preferable because the release layer of the present invention has sufficient adhesion to it. In addition, the base | substrate surface may be comprised with the single material and may be comprised with two or more materials. As an aspect 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 other surface is composed of other materials. A dot pattern is formed on the entire surface of the substrate. There is a mode in which a material in a pattern such as a line and space pattern is present in other materials.

The method for applying the release layer-forming composition of the present invention to the substrate is not particularly limited, and examples thereof include cast coating, spin coating, blade coating, dip coating, roll coating, and bar coating. Method, die coating method, ink jet method, printing method (eg, relief printing, intaglio printing, planographic printing, screen printing, etc.).

Examples of the appliance 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, and preferably about 0.05 to 20 μm from the viewpoint of productivity. In addition, desired thickness is implement | achieved by adjusting the thickness of the coating film before a heating.

The release layer described above has excellent adhesion to a substrate, particularly a glass substrate, moderate adhesion to a resin substrate, and moderate release. Therefore, the release layer of the present invention peels the resin substrate from the substrate together with the circuit formed on the resin substrate without damaging the resin substrate of the device in the manufacturing process of the flexible electronic device. Therefore, it can be suitably used.

Hereinafter, an example of the manufacturing method of the flexible electronic device using the peeling layer of this invention is demonstrated.
Using the composition for forming a release layer of the present invention, a release layer is formed on a glass substrate by the method described above. On this release layer, a resin substrate forming solution for forming a resin substrate is applied, and this coating film is baked, so that the resin substrate fixed to the glass substrate via the release layer of the present invention is obtained. Form.
The firing temperature of the coating film is appropriately set according to the type of resin and the like. In the present invention, the maximum temperature during firing is preferably 450 ° C. or higher, and preferably 480 ° C. or higher. Is more preferably 490 ° C. or higher, and further preferably 500 ° C. or higher. By setting the maximum temperature during firing at the time of resin substrate production within this range, the adhesiveness between the release layer and the substrate as the base, and the appropriate adhesiveness and peelability between the release layer and the resin substrate are further improved be able to.
In this case, as long as the maximum temperature falls within the above range, a step of baking at a temperature lower than that may be included.

As a preferable example of the heating mode at the time of preparing the resin substrate, there is a method of heating at 50 to 150 ° C., then increasing the heating temperature step by step, and finally heating at 450 ° C. or higher. In particular, as a more preferable example of the heating mode, a method of heating at 50 to 100 ° C., heating at a temperature exceeding 100 ° C. to less than 400 ° C., and heating at 450 ° C. or higher can be mentioned. Furthermore, as another more preferable example of the heating mode, after heating at 50 to 100 ° C., heating is performed at over 100 ° C. to 200 ° C., then over 200 ° C. to less than 300 ° C., and heating is performed at 300 ° C. to less than 400 ° C. And heating at 400 to 450 ° C., and finally heating at 450 to 510 ° C. can be mentioned.

Further, as a preferable example of the heating mode in consideration of the firing time, after heating at 50 to 150 ° C. for 1 minute to 2 hours, the heating temperature is increased stepwise and finally at 450 ° C. or higher for 30 minutes. A method of heating for up to 4 hours can be mentioned. In particular, as a more preferable example of the heating mode, heating is performed at 50 to 100 ° C. for 1 minute to 2 hours, heating is performed above 100 ° C. to less than 400 ° C. for 5 minutes to 2 hours, and heating is performed at 450 ° C. or higher for 30 minutes to 4 hours. The technique to do is mentioned. Furthermore, as another more preferable example of the heating mode, after heating at 50 to 100 ° C. for 1 minute to 2 hours, after heating at 100 ° C. to 200 ° C. for 5 minutes to 2 hours, then above 200 ° C. to less than 300 ° C. 30 For example, a method of heating at 300 to 400 ° C. for 30 minutes to 4 hours, 400 to 450 ° C. for 30 minutes to 4 hours, and finally 450 to 510 ° C. for 30 minutes to 4 hours may be mentioned.

The resin substrate covers the entire release layer, and the substrate is formed with an area larger 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 method for forming the resin substrate may follow a conventional method.

Next, a desired circuit is formed on the resin substrate fixed to the base via the release layer of the present invention, and then the resin substrate is cut along the release layer, for example. It peels from a peeling layer, and a resin substrate and a base | substrate are isolate | separated. At this time, a part of the substrate may be cut together with the release layer.

In JP 2013-147599 A, it is reported that the laser lift-off method (LLO method) that has been used in the manufacture of high-brightness LEDs, three-dimensional semiconductor packages and the like is applied to the manufacture of flexible displays. . The LLO method is characterized in that light having a specific wavelength, for example, light having a wavelength of 308 nm, is irradiated from the surface opposite to the surface on which a circuit or the like is formed from the glass substrate side. The irradiated light passes through the glass substrate, and only the polymer (polyimide) in the vicinity of the glass substrate absorbs this light and evaporates (sublimates). As a result, it is possible to selectively peel the resin substrate from the glass substrate without affecting the circuit or the like provided on the resin substrate, which determines the performance of the display.

The release layer of the present invention has a feature of sufficiently absorbing light having a specific wavelength (for example, 308 nm) that enables application of the above LLO method, and therefore can be used as a sacrificial layer of the LLO method. Therefore, when a desired circuit is formed on a resin substrate fixed to a glass substrate through a release layer formed by using the composition according to the present invention, and then an LLO method is performed to irradiate a light beam of 308 nm. Only the release layer absorbs this light and evaporates (sublimates). Thereby, the release layer is sacrificed (acts as a sacrifice layer), and the resin substrate can be selectively peeled from the glass substrate.

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

[1] Abbreviations of compounds NMP: N-methylpyrrolidone BCS: butyl cellosolve p-PDA: p-phenylenediamine 2AP: 2-aminophenol BPDA: 3,3-4,4-biphenyltetracarboxylic dianhydride PMDA: pyromerit Acid dianhydride

[2] Measurement of weight average molecular weight and molecular weight distribution The polymer weight average molecular weight (hereinafter abbreviated as Mw) and molecular weight distribution were measured using a GPC apparatus (Shodex (registered trademark) columns KF803L and KF805L) manufactured by JASCO Corporation. As a measurement, dimethylformamide was measured under the conditions of a flow rate of 1 ml / min and a column temperature of 50 ° C. In addition, Mw was made into the polystyrene conversion value.

[3] Synthesis of polymer Polyamic acid was synthesized by the following method.
In addition, the polymer was not isolated from the obtained polymer containing reaction liquid, but the resin substrate formation composition or the peeling layer formation composition was prepared by diluting a reaction liquid as mentioned later.

<Synthesis Example S1 Polyamic Acid (Synthesis of S1)>
3.176 g (0.02937 mol) of p-PDA was dissolved in 88.2 g of NMP, and 8.624 g (0.02931 mol) of BPDA was added, followed by reaction at 23 ° C. for 24 hours in a nitrogen atmosphere. Mw of the obtained polymer was 107,300, and the molecular weight distribution was 4.6.

<Synthesis Example L1 Synthesis of polyamic acid (L1)>
p-PDA (1.507 g, 0.0139 mol) was dissolved in NMP (43.2 g), PMDA (3.166 g, 0.01452 mol) was added, and the mixture was reacted at 23 ° C. for 2 hours in a nitrogen atmosphere. Thereafter, 0.127 g (0.0012 mol) of 2AP was further added and reacted at 23 ° C. for 24 hours in a nitrogen atmosphere. Mw of the obtained polymer was 48,500 and molecular weight distribution was 2.05.

<Synthesis Example L2 Synthesis of polyamic acid (L2)>
1.119 g (0.01103 mol) of p-PDA was dissolved in 35.2 g of NMP, and 3.006 g (0.01378 mol) of PMDA was added, followed by reaction at 23 ° C. for 2 hours in a nitrogen atmosphere. Thereafter, 0.602 g (0.00551 mol) of 2AP was further added and reacted at 23 ° C. for 24 hours in a nitrogen atmosphere. Mw of the obtained polymer was 11,700 and molecular weight distribution was 1.76.

<Synthesis Example L3 Synthesis of polyamic acid (L3)>
0.681 g (0.00629 mol) of p-PDA was dissolved in 35.2 g of NMP, and 2.746 g (0.01259 mol) of PMDA was added, followed by reaction at 23 ° C. for 2 hours in a nitrogen atmosphere. Thereafter, 1.373 g (0.012588 mol) of 2AP was further added, and the mixture was reacted at 23 ° C. for 24 hours in a nitrogen atmosphere. Mw of the obtained polymer was 8,000 and molecular weight distribution was 1.57.

<Synthesis of Comparative Synthesis Example HL1 Polyamic Acid (HL1)>
1.29 g (0.00107 mol) of p-PDA was dissolved in 43.2 g of NMP, and 3.509 g (0.00119 mol) of BPDA was added, followed by reaction at 23 ° C. for 24 hours in a nitrogen atmosphere. Mw of the obtained polymer was 34,000 and molecular weight distribution was 2.03.

<Synthesis of Comparative Synthesis Example HL2 Polyamic Acid (HL2)>
1.325 g (0.00123 mol) of p-PDA was dissolved in 36 g of NMP, and 2.674 g (0.00123 mol) of PMDA was added, followed by reaction at 23 ° C. for 2 hours in a nitrogen atmosphere. Unfortunately, it was gelled and could not be used.

[4] Preparation of Resin Substrate Forming Composition Each of the reaction solutions obtained in Synthesis Example S1 was directly used as a resin substrate forming composition.

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

[Examples 1-2 to 1-3]
A composition for forming a release layer was obtained in the same manner as in Example 1-1 except that the reaction solutions obtained in Synthesis Examples L2 to L3 were used in place of the reaction solution obtained in Synthesis Example L1, respectively. It was.

[Comparative Example 1-1]
A composition for forming a release layer was obtained in the same manner as in Example 1-1, except that the reaction solution obtained in Comparative Synthesis Example HL1 was used instead of the reaction solution obtained in Synthesis Example L1. .

[6] Production of release layer and resin substrate [Example 2-1]
Using a spin coater (conditions: about 3,000 rpm for about 30 seconds), the release layer forming composition L1 obtained in Example 1-1 was used as a glass substrate of 100 mm × 100 mm glass substrate (hereinafter the same). It was applied on top.
The obtained coating film was heated at 100 ° C. for 2 minutes using a hot plate, and then heated at 300 ° C. for 30 minutes using an oven, and the heating temperature was raised to 400 ° C. (10 ° C./min. And then heated to 400 ° C. for 30 minutes, further heated to 500 ° C. (10 ° C./min), and heated at 500 ° C. for 10 minutes to form a release layer having a thickness of about 0.1 μm on the glass substrate. A glass substrate with a release layer was obtained. During the temperature increase, the film-coated substrate was not removed from the oven but heated in the oven.

Using a bar coater (gap: 250 μm), the resin substrate forming composition S2 was applied on the release layer (resin thin film) on the glass substrate obtained above. Then, the obtained coating film was heated at 80 ° C. for 30 minutes using a hot plate, and then the atmosphere was changed to a nitrogen atmosphere using an oven, followed by heating at 140 ° C. for 30 minutes, and the heating temperature was raised to 210 ° C. Temperature (2 ° C./min, the same applies hereinafter), 210 ° C. for 30 minutes, heating temperature to 300 ° C., 300 ° C. for 30 minutes, heating temperature to 400 ° C., 400 ° C. for 30 minutes, The heating temperature was raised to 500 ° C. and heated at 500 ° C. for 60 minutes to form a polyimide resin substrate having a thickness of about 20 μm on the release layer, thereby obtaining a glass substrate with a resin substrate / release layer. During the temperature increase, the film-coated substrate was not removed from the oven but heated in the oven.

[Examples 2-2 to 2-3]
Except that the release layer-forming composition L2 and L3 obtained in Examples 1-2 to 1-3 were used in place of the release layer-forming composition L1 obtained in Example 1-1, respectively. In the same manner as in Example 2-1, a release layer and a polyimide resin substrate were formed to obtain a glass substrate with a release layer and a resin substrate / glass substrate with a release layer.

[Comparative Example 2-1]
The same procedure as in Example 2-1 except that the release layer forming composition HL1 obtained in Comparative Example 1-1 was used instead of the release layer forming composition L1 obtained in Example 1-1. By the method, a release layer and a polyimide resin substrate were formed, and a glass substrate with a release layer and a glass substrate with a resin substrate / release layer were obtained.

[7] Evaluation of peelability With respect to the glass substrate with a release layer obtained in Examples 2-1 to 2-3 and Comparative Example 2-1, the peelability between the release layer and the glass substrate was confirmed by the following method. did. In addition, the following test was done with the same glass substrate.

<Cross-cut test peelability evaluation of resin thin film>
The release layer on the glass substrate with the release layer obtained in Examples 2-1 to 2-3 and Comparative Example 2-1 was cross-cut (1 mm in length and width, the same applies hereinafter), and 100 mass cuts were performed. That is, 100 crosses of 1 mm square were formed by this cross cut.
Then, an adhesive tape was affixed to the 100 muscat portion, the tape was peeled off, and peelability was evaluated based on the following criteria (5B to 0B, B, A, AA). The results are shown in Table 1.
<Criteria>
5B: 0% peeling (no peeling)
4B: Less than 5% peeling 3B: Less than 5-15% peeling 2B: 15-35% peeling 1B: 35-65% peeling 0B: 65% -80% peeling B: 80% -95 % Peeling A: 95% to less than 100% peeling AA: 100% peeling (all peeling)

<Evaluation of peelability of resin substrate>
The resin substrate / glass substrate with release layer obtained in Examples 2-1 to 2-3 and Comparative Example 2-1 was cut into a 25 mm wide strip using a cutter. And the cellophane tape was affixed on the front-end | tip of the cut resin substrate, and this was made into the test piece. The test piece was subjected to a peel test using an Atonic Co., Ltd. push-pull tester so that the peel angle was 90 °, and peelability was evaluated based on the following criteria. The results are shown in Table 1.
<Criteria>
5B: 0% peeling (no peeling)
4B: Less than 5% peeling 3B: Less than 5-15% peeling 2B: 15-35% peeling 1B: 35-65% peeling 0B: 65% -80% peeling B: 80% -95 % Peeling A: 95% to less than 100% peeling AA: 100% peeling (all peeling)

From the results shown in Table 1, the release layers of Examples 2-1 to 2-3 were able to peel only the resin substrate without peeling off the release layer from the glass substrate, but could not be peeled off in Comparative Example 2-1. It was confirmed.

Claims

A release layer-forming composition comprising a polyamic acid having both ends derived from tetracarboxylic acid and one or both of both ends sealed with 2-aminophenol and an organic solvent is formed on a substrate. A method for producing a release layer, comprising a step of applying and baking at a maximum temperature of 400 ° C. or higher.
The method for producing a release layer according to claim 1, wherein the polyamic acid is a polyamic acid obtained by reacting a diamine component containing an aromatic diamine and an acid dianhydride component containing an aromatic tetracarboxylic dianhydride. .
The method for producing a release layer according to claim 2, wherein the aromatic diamine is an aromatic diamine containing 1 to 5 benzene nuclei.
The method for producing a release layer according to claim 2 or 3, wherein the aromatic tetracarboxylic dianhydride is an aromatic tetracarboxylic dianhydride containing 1 to 5 benzene nuclei.
A method for producing a flexible electronic device comprising a resin substrate, comprising using a release layer formed using the production method according to any one of claims 1 to 4.
A process of forming a resin substrate by applying a resin substrate-forming composition on a release layer formed by using the manufacturing method according to any one of claims 1 to 4 and then baking it at a maximum temperature of 450 ° C or higher. A method for manufacturing a flexible electronic device.
The method for manufacturing a flexible electronic device according to claim 5 or 6, wherein the resin substrate is a polyimide resin substrate.