TW201443155A - Production method for resin thin film for display substrate and resin thin film forming composition for display substrate - Google Patents

Abstract

To provide a production method which provides a resin thin film that is suitable for a substrate for flexible displays, said resin thin film having high heat resistance, good flexibility and good separability from glass. A method for producing a resin thin film for display substrates, which is characterized by comprising a step wherein a composition for forming a resin thin film, said composition containing a polyamic acid that is represented by formula (1-1) and has a weight average molecular weight of 5,000 or more, is applied to a base and heated thereon. (In the formula, each of Ar1 and Ar2 represents, for example, a biphenyl-3,3',4,4'-tetrayl group; and m represents the number of repeating units, which is a positive integer.)

Description

Method for producing resin film for display substrate and resin film forming composition for display substrate

The present invention relates to a method for producing a resin film for a display substrate and a composition for forming a resin film for a display substrate.

In recent years, in the field of display devices such as organic electroluminescence (hereinafter also referred to as organic EL) displays and liquid crystal displays, the demand for ultrathinness, light weight, and flexibility has been gradually increased, and soft resins as substrate materials have been gradually improved. The materials are attracting attention.

On the other hand, in a high-definition display, an active matrix-driven panel is used. In this process, in addition to a matrix-shaped pixel electrode, when an active matrix layer including a thin film active device is formed, it is necessary to perform 200 ° C or more. The situation may even require high temperature treatment above 300 °C.

Therefore, when a resin material is used instead of glass as a substrate material of a display, high heat resistance is required for the resin material.

At this point, it is known that polybenzoxazole has high heat resistance, A film made of polybenzoxazole applied to a substrate material and a method for producing the same have been proposed, and reports have been made (Patent Documents 1 to 4).

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese International Publication No. 2001/34679

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2001-348428

[Patent Document 3] Japanese International Publication No. 2006/126454

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2004-231875

However, a method for producing a film or the like for producing a substrate suitable for a display using a material which is particularly suitable for a mass production program of a flexible display and which can be easily prepared is not fully described.

The present invention has been made in view of the above circumstances, and it is an object of the invention to provide a resin film-forming composition which can be easily prepared, and which can impart heat resistance and moderate softness to a high-temperature treatment in a process capable of withstanding a flexible display. A method for producing a resin film having good peelability from a glass substrate, and a composition for forming a resin film.

The term "appropriate softness" as used herein refers to a high degree of softness which is self-supporting and does not break even if it is bent at 90 degrees. In addition, the term "peelability" means that the resin film itself does not naturally fall off from the substrate on which the resin film is formed, but has a process that can be easily peeled off by external force. Degree, and the substrate used in the mass production procedure is sufficiently tight.

The inventors of the present invention conducted intensive studies to achieve the above object, and as a result, found that a polylysine comprising a skeleton derived from a specific aromatic dianhydride and a specific aromatic diamine is contained by at least 60 mol% or more. The resin film-forming composition is applied onto a glass substrate and heated to produce a resin film which is particularly suitable for use as a substrate of a display. Thus, the present invention has been completed.

Patent Document 4 discloses a method for producing a film using polyimine, but a composition for forming a resin film for a display substrate containing polyglycine according to the present invention, a method for producing the same, and a method for producing the same The resin film obtained by the method has characteristics particularly suitable for use in a display substrate, and does not reveal anything.

In other words, the present invention provides a method for producing a resin film for a display substrate, which comprises a resin film containing a polyaminic acid having a weight average molecular weight of 5,000 or more represented by the following formula (1-1). Forming the composition to be applied to the substrate and heating, [In the formula (1-1), Ar ¹ represents a tetravalent group represented by the following formula (2) or (3), and Ar ² represents a formula (4-1), a formula (4-2) or a formula: (5) represents the base of the 4 valence, m represents the number of repeating units and is a positive integer] (In equations (2) and (3), the star mark and the wavy line mark indicate the bond key, one of the two key bonds with the star mark, and the two key bonds with the wavy line mark. 1 line and carboxyl bond) (In equations (4-1), (4-2), and (5), the star mark and the wavy line mark represent the bond key, and one of the two key bonds with the star mark is attached with a wave. A method of manufacturing a polyacetic acid according to the following formula (1-2), wherein the one of the two bond bonds of the line mark is bonded to a hydroxy group. In the formula (1-2), X represents a divalent group represented by any one of the following formulas (6) to (8), and Ar ¹ , Ar ² and m represent the same as defined above; [In the formulae (6) to (8), R ¹ to R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and Y represents 1 represented by the following formula (9) or (10); The base of the valence, n represents the number of Y bonded to the aromatic ring and is an integer of 1 to 3, and the star symbol indicates a bonding bond; (In the formulae (9) and (10), R ⁵ to R ⁸ each independently represent a hydrogen atom or an aryl group having 6 to 20 carbon atoms, and a star symbol indicates a bond bond)], 3. such as 1. 2. The method of manufacturing, wherein the substrate is a glass substrate, the method of any one of 1. to 3. wherein the heating is performed by increasing the heating temperature stepwise, 5. The manufacturing method, wherein the step of gradually increasing the heating temperature is carried out in the following steps: heating at 50 ° C to 100 ° C for 5 minutes to 2 hours, heating at more than 100 ° C to 200 ° C for 5 minutes to 2 hours, at over 200 ° C 375 ° C heating for 5 minutes to 2 hours, and then heating at 375 ° C ~ 500 ° C for 30 minutes to 4 hours, 6. A resin film for a display substrate, which is a manufacturing method according to any one of 1. to 5. The present invention is a flexible display substrate comprising a resin film for a display substrate as shown in Fig. 6. A composition for forming a resin film for a display substrate, which comprises the following formula (1) 1) a polylysine having a weight average molecular weight of 5,000 or more, [In the formula (1-1), Ar ¹ represents a tetravalent group represented by the following formula (2) or (3), and Ar ² represents a formula (4-1), a formula (4-2) or a formula: (5) represents the base of the 4 valence, m represents the number of repeating units and is a positive integer] (In equations (2) and (3), the star mark and the wavy line mark indicate the bond key, one of the two key bonds with the star mark, and the two key bonds with the wavy line mark. 1 line and carboxyl bond) (In equations (4-1), (4-2), and (5), the star mark and the wavy line mark represent the bond key, and one of the two key bonds with the star mark is attached with a wave. The one of the two bonding bonds of the line symbol and the hydroxy group), 9. The composition for forming a resin film for a display substrate according to 8, wherein the polylysine is represented by the following formula (1-2) , {In the formula (1-2), X denotes a formula represented by the following formula (6) to (8) of any 2-valent group, Ar ^1, Ar ² and m are as defined above; [In the formulae (6) to (8), R ¹ to R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and Y represents 1 represented by the following formula (9) or (10); The base of the valence, n represents the number of Y bonded to the aromatic ring and is an integer of 1 to 3, and the star symbol indicates a bonding bond; (In the formulae (9) and (10), R ⁵ to R ⁸ each independently represent a hydrogen atom or an aryl group having 6 to 20 carbon atoms, and a star symbol indicates a bonding bond)]}.

A flexible display using a resin film as a substrate By the following steps: a step of forming a resin film on a glass substrate of a material excellent in heat resistance, and sequentially forming an active matrix layer or the like on the resin film at a high temperature, and then forming There is a step of peeling off the resin film of the active matrix layer or the like from the glass substrate.

According to the production method of the present invention, a resin film having high heat resistance and good flexibility and exhibiting good releasability with glass can be produced, and the composition for forming a resin film of the present invention used in the production method can be produced. In the manufacture of a flexible display, it is advantageous for cost reduction, simplification of the process, improvement of the yield, and the like.

The invention is described in detail below.

In the production method of the present invention, a composition for forming a resin film comprising polyamic acid having a weight average molecular weight of 5,000 or more represented by the following formula (1-1) is used.

In the above formula (1-1), m represents the number of repeating units and is a positive integer.

Further, Ar ¹ represents a tetravalent group represented by the following formula (2) or formula (3).

In the formulas (2) and (3), the star mark and the wavy line mark represent a bond bond, and a single bond between each benzene ring means that it is located at any position of the benzene ring. For example, the tetravalent group represented by the formula (2) is a group in which two benzene rings are bonded by any one of the formulae (2-1) to (2-3).

Further, in the equations (2) and (3), one of the two keying keys with a star mark and one of the two keying keys with a wavy line mark are attached to the formula. Carboxyl bond of Ar ¹ in (1-1). For example, when Ar ¹ is a group represented by the formula (2-1), the carboxyl group in the formula (1-1) is bonded to Ar ¹ in any of the formulae (A) to (C).

Examples of the group represented by the formula (2) or the formula (3) include the formula (2-1) to the formula (2-3), and the formula (3-1) or the formula (3-2). Base and so on.

In particular, when a resin film having high flexibility is produced with good reproducibility, Ar ^{1 is} preferably a group represented by formula (2-1) or formula (3-1), and a dianhydride as a raw material is considered. The ease of obtaining is particularly preferable to the formula (2-1).

In the formula (1-1), Ar ² represents represents the following formula (4-1), (4-2) or (5) a tetravalent group.

In the formula (4-1), the formula (4-2), and the formula (5), the star mark and the wavy line mark represent a bond bond, and the single bond between the two benzene rings in the formula (5), and the above The same means that it is located anywhere in the benzene ring.

In the formula (4-1), the formula (4-2), and the formula (5), one of the two key bonds with the star mark and one of the two bond keys with the wavy line mark And bonding to a carboxyl group bonded to Ar ² in the formula (1-1). For example, when Ar ² is a group represented by the formula (4-2), the carboxyl group in the formula (1-1) is bonded to Ar ² in any of the formulae (D) to (F).

In particular, when the ease of obtaining the diamine as a raw material is considered, Ar ^{2 is} preferably a group represented by the following formula (4-1) or a group represented by the following formula (5-1), and the reproducibility is considered. When a resin film having high flexibility is produced in a fine manner, it is particularly preferably a group represented by the formula (5-1).

In the present invention, by using polylysine which has an unsaturated bond at both terminals and is represented by the following formula (1-2), as the polyamine acid represented by the above formula (1-1), it can be produced. A resin film with higher flexibility and higher heat resistance.

In the formula (1-2), X represents a divalent group represented by any one of the following formulae (6) to (8), and Ar ¹ , Ar ² and m represent the same as defined above.

In the formula (6), Y represents a monovalent group represented by the following formula (9) or formula (10), and a star symbol indicates a bond bond.

In the formulae (9) and (10), R ⁵ to R ⁸ each independently represent a hydrogen atom or an aryl group having 6 to 20 carbon atoms.

Examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-fluorenyl group, a 2-fluorenyl group, a 9-fluorenyl group, a 1-phenanthryl group, and a 2-phenanthryl group. , 3-phenanthryl, 4-phenanthryl, 9-phenanthryl and the like.

R ⁵ to R ⁸ , in order to increase the solubility of the polyamic acid in an organic solvent, preferably a hydrogen atom or an aryl group having 14 or less carbon atoms, particularly preferably a hydrogen atom or an aryl group having 10 or less carbon atoms. More preferably, it is a hydrogen atom or a phenyl group. Further, it is preferred that at least one of R ⁵ to R ⁷ is a hydrogen atom, and two of them are a hydrogen atom.

In the formula (6), n represents the number of Y bonded to the aromatic ring and is an integer of 1 to 3, preferably 1 or 2. When n is 2 or more, the plurality of Ys may be the same or different.

In the formulae (7) and (8), R ¹ to R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

An alkyl group having 1 to 20 carbon atoms, which may be a linear or branched chain Any of the form and the ring may, for example, be a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a secondary butyl group, a tertiary butyl group, a n-pentyl group or a hexyl group. a linear or branched chain alkyl group having 1 to 20 carbon atoms, such as a group, a n-heptyl group, an n-octyl group, a n-decyl group or a n-decyl group; a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a ring Hexyl, cycloheptyl, cyclooctyl, cyclodecyl, cyclodecyl, dicyclobutyl, dicyclopentyl, dicyclohexyl, bicycloheptyl, bicyclooctyl, bicyclononyl, bicyclo A cyclic alkyl group having 3 to 20 carbon atoms, such as a group.

R ¹ to R ⁴ , in order to increase the solubility of the polyamic acid in an organic solvent, preferably a hydrogen atom or an alkyl group having 10 or less carbon atoms, particularly preferably a hydrogen atom or an alkyl group having 4 or less carbon atoms. More preferably, it is a hydrogen atom or a methyl group. Further, each of R ¹ and R ² , R ³ and R ⁴ is preferably a hydrogen atom.

The polylysine used in the present invention contains at least 60 mol% of a repeating unit represented by the following formula (1), preferably 70 mol% or more, based on the entire repeating unit constituting the polyamic acid. More preferably, it is more than 80% by mole, more preferably 90% by mole. By using the polyamic acid, a resin film having high heat resistance suitable for a display substrate can be produced with good reproducibility.

(wherein, Ar ¹ , Ar ² and m are synonymous with the foregoing)

The lower limit of the weight average molecular weight of polylysine, taking into account the maintenance The heat resistance of the obtained film is 5,000 or more, preferably 10,000 or more, particularly preferably 15,000 or more, and more preferably 20,000 or more. On the other hand, the upper limit of the weight average molecular weight of the polylysine used in the present invention is usually 2,000,000 or less, but it is considered that the viscosity of the varnish is too high, and the resin having high flexibility is excellent in reproducibility. The film or the like is preferably 1,000,000 or less, and more preferably 200,000 or less.

The polyamic acid to be used in the present invention may contain other repeating units in addition to the repeating unit represented by the above formula (1), and the content of the repeating unit must be based on the entire repeating unit constituting the polylysine. Less than 40% by mole, preferably less than 30% by mole, especially less than 20% by mole, more preferably less than 10% by mole.

The polyamic acid represented by the above formula (1-1) used in the present invention can be obtained by reacting a diamine represented by the following formula (11) and a dianhydride represented by the following formula (12).

(wherein, Ar ¹ and Ar ^{2 are} synonymous with the foregoing)

The diamine represented by the formula (11) and the dianhydride represented by the formula (12) can be used commercially or by a method known by a general method.

Examples of the diamine represented by the formula (11) include 4,6-diaminoresorcinol, 3,3'-dihydroxybenzidine, and 3,3'-diamino-4,4'-di. Hydroxybiphenyl or the like, but is not limited thereto.

Examples of the dianhydride represented by the formula (12) include 4,4'-diphthalic anhydride, 3,3'-diphthalic anhydride, 3,4'-diphthalic anhydride, and 1 , 1': 4', 1"-terphenyl-3,3",4,4"-tetracarboxylic dianhydride, 1,1':3',1"-terphenyl-3,4,3", 4"-tetracarboxylic dianhydride or the like, but is not limited thereto.

Further, the polyamic acid represented by the above formula (1-2) used in the present invention can be obtained by using the diamine represented by the above formula (11), the dianhydride represented by the above formula (12), and The acid anhydride (hereinafter also referred to as terminal blocking material) represented by any one of the above formulas (13) to (15) is obtained by reaction.

(wherein R ¹ to R ⁴ , Y and n are synonymous with the foregoing)

The acid anhydride represented by any one of the formulae (13) to (15) may be a commercially available product or a compound which is synthesized by a generally known method.

Examples of the acid anhydride represented by the formula (13) include 3-vinylphthalic anhydride, 4-vinylphthalic anhydride, 4-phenylethynylphthalic anhydride, and 4-ethynylorthobenzene. Dicarboxylic anhydride or the like, but is not limited thereto.

Examples of the acid anhydride represented by the formula (14) include 5-northene-2,3-dicarboxylic anhydride and methyl-5-nordecene-2,3-dicarboxylic anhydride, but are not limited thereto. Wait.

The acid anhydride represented by the formula (15) may, for example, be maleic anhydride or citraconic anhydride, but is not limited thereto.

In the above reaction, the ratio of the diamine represented by the above formula (11) and the anhydride (dianhydride and anhydride) represented by any one of the above formulas (12) to (15) can be measured. The molecular weight of the synthesized poly-proline is appropriately set, and the acid anhydride is usually set to be about 0.6 to 1.4, preferably 0.8 to 1.2, based on the diamine.

The above reaction is preferably carried out in a solvent, and when the solvent to be used is used, the type may be any one as long as it does not adversely affect the reaction, and various solvents can be used.

Specific examples thereof include m-cresol, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, and N. N-dimethylacetamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropanamide, 3-ethoxy-N,N-dimethyl Propylamine, 3-propoxy-N,N-dimethylpropanamide, 3-isopropoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-di Methyl propylamine, 3-secondary butoxy-N,N-dimethylpropanamide, 3-tertiary butoxy-N,N-dimethylpropanamide, γ-butyrolactone, etc. Protonic solvent, etc. These may be used alone or in combination of two or more.

The reaction temperature can be appropriately set within the range from the melting point to the boiling point of the solvent to be used, and is usually about 0 to 100 ° C, but in order to prevent the imidization of the obtained polylysine to maintain the polyamine unit The high content is preferably from about 0 to 70 ° C, more preferably from about 0 to 60 ° C, more preferably from about 0 to 50 ° C.

The reaction time is dependent on the reaction temperature and the reactivity of the starting materials, and cannot be generalized, and is usually about 1 to 100 hours.

After the reaction is completed, the post-treatment is carried out according to the general method to achieve the purpose. Polylysine is isolated.

In the production method of the present invention, a varnish obtained by dissolving or dispersing the separated polylysine in a solvent is used as a composition for forming a resin film. In particular, when it is considered to produce a film having high flatness with good reproducibility, polylysine is preferably dissolved in a solvent.

Further, the reaction solution containing the polyamic acid obtained by the above reaction may be used as it is, or diluted or concentrated to be used as a resin film forming composition for a varnish, and used in the production method of the present invention.

The solvent to be used for dilution, dissolution or dispersion is not particularly limited as long as it can dissolve or disperse the polyamic acid. The solvent is the same as the specific example of the reaction solvent of the above reaction, and these may be used alone or in combination of two or more.

Among these, when a resin film having high flatness is obtained with good reproducibility, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl is preferred. 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone.

The concentration (solid content concentration) of the total mass of the polyglycolic acid relative to the varnish (the composition for forming a resin film) can be appropriately set in consideration of the thickness of the produced film or the viscosity of the varnish, and is usually about 0.5 to 30. The mass% is preferably about 5 to 25% by mass.

In addition, the viscosity of the varnish is appropriately set in consideration of the thickness of the film to be produced, and the like, especially when a resin film having a thickness of about 5 to 50 μm is obtained with good reproducibility, usually at about 25 ° C. 500~50,000 mPa‧s, preferably about 1,000~20,000 mPa‧s.

The resin film used in the production method of the present invention is used for forming The composition may contain a crosslinking agent (hereinafter also referred to as a crosslinkable compound). The content of the crosslinking agent is usually 20 parts by mass or less based on 100 parts by mass of the polyamic acid.

Examples of the crosslinkable compound include a compound containing two or more epoxy groups, a melamine derivative having a hydrogen atom of an amine group substituted with a methylol group, an alkoxymethyl group or both, and benzene. Further, the guanamine derivative or the glycoluril or the like is not limited thereto.

Specific examples of the crosslinkable compound are listed below, but are not limited thereto.

Examples of the compound containing two or more epoxy groups include Epolead GT-401, Epolead GT-403, Epolead GT-301, Epolead GT-302, Celloxide 2021, and Celloxide 3000 (manufactured by Daicel Co., Ltd.). Epoxy compound having a cyclohexene structure; Epikote 1001, Epikote 1002, Epikote 1003, Epikote 1004, Epikote 1007, Epikote 1009, Epikote 1010, Epikote 828 (above, manufactured by Japan Epoxy Resin Co., Ltd. (now Mitsubishi Chemical Co., Ltd.) Bisphenol A epoxy compound such as company, jER (registered trademark) series), etc.; bisphenol F epoxy compound such as Epikote 807 (made by Japan Epoxy Resin Co., Ltd.); Epikote 152, Epikote 154 (above a phenol-phenolic epoxy compound manufactured by Japan Epoxy Resin Co., Ltd. (currently manufactured by Mitsubishi Chemical Corporation, jER (registered trademark) series), EPPN201 EPPN202 (above, manufactured by Nippon Kayaku Co., Ltd.); ECON -102, ECON-103S, ECON-104S, ECON-1020, ECON-1025, ECON-1027 (the above is manufactured by Nippon Kayaku Co., Ltd.), and Epikote 180S75 (the above is manufactured by Japan Epoxy Resin Co., Ltd. (currently manufactured by Mitsubishi Chemical Corporation, jER (registered trademark) series), etc.) a cresol-phenolic epoxy compound; a naphthalene epoxy compound such as V8000-C7 (manufactured by DIC Corporation); Denacol EX-252 (manufactured by Nagase Chemtex Co., Ltd.), CY175, CY177, CY179, Araldite CY- 182, Araldite CY-192, Araldite CY-184 (above, manufactured by BASF Corporation), Epiclon 200, Epiclon 400 (above, manufactured by DIC Corporation), Epikote 871, Epikote 872 (above, manufactured by Japan Epoxy Resin Co., Ltd.) An alicyclic epoxy compound such as MITSUBISHI CHEMICAL CO., LTD., jER (registered trademark) series), ED-5661, ED-5662 (the above is manufactured by Celanese Coating Co., Ltd.); Denacol EX-611, Denacol EX-612, Denacol EX-614, Denacol EX-622, Denacol EX-411, Denacol EX-512, Denacol EX-522, Denacol EX-421, Denacol EX-313, Denacol EX-314, Denacol EX-312 (above) Is manufactured by Nagase Chemtex Co., Ltd.) Aliphatic polyglycidyl ether compound.

A melamine derivative, a benzoguanamine derivative or a glycoluril having a hydrogen atom of an amine group substituted by a methylol group, an alkoxymethyl group or both, and a methoxy group of each triazine ring is exemplified. The average of MX-750 was replaced by 3.7, and the methoxymethyl group of each triazine ring was replaced by 5.8 MW-30 (manufactured by Sanwa Chemical Co., Ltd.); Cymel 300, Cymel 301, Cymel 303, Cymel 350, Cymel 370, methoxymethylated melamine of Cymel 771, Cymel 325, Cymel 327, Cymel 703, Cymel 712, etc.; methoxymethylated butyl of Cymel 235, Cymel 236, Cymel 238, Cymel 212, Cymel 253, Cymel 254, etc. Oxymethylated melamine; Cymel 506, Cymel 508, etc., butoxymethylated melamine; Cymel 1141, carboxylated methoxymethylated isobutoxymethylated melamine; Cymel 1123, methoxymethylated Oxymethylated benzoguanamine; Cymel 1123-10 methoxymethylated butoxymethylated benzoguanamine; Cymel 1128-like butoxymethylated benzoguanamine; Cymel 1125-80 Carboxy-containing methoxymethylated ethoxymethylated benzoguanamine; Cymel 1170-like butoxymethylated glycoluril; Cymel 1172-like methylolated glycoluril (above manufactured by Mitsui Cyanamid Co., Ltd.) It is now manufactured by Nihon Cytec Industries Co., Ltd.).

The resin film-forming composition containing the polyaminic acid represented by the above formula (1-1) is particularly suitable for producing a resin film used as a display substrate, and the resin film-forming composition is also an object of the present invention.

In the production method of the present invention, the resin film-forming composition described above is applied to a substrate.

Examples of the substrate include plastics (polycarbonate, polymethacrylate, polystyrene, polyester, polyolefin, epoxy, melamine, triacetyl cellulose, ABS, AS, norbornene-based resin, etc.). Metal, wood, paper, glass, slate, etc., since the obtained resin film can exhibit good peelability, it is most suitable as a glass substrate.

The glass substrate to be used may be any glass or a part of the surface on which the resin film-forming composition is applied, and since the obtained resin film can exhibit good releasability, it is preferred to use all of the coated surfaces. A glass substrate such as a glass substrate of glass.

The coating method is not particularly limited, and examples thereof include a casting coating method, a spin coating method, a sheet coating method, a dip coating method, a roll coating method, a bar coating method, a die casting coating method, and an inkjet method. Law, printing method (embossing, concave, flat, screen printing, etc.).

In the production method of the present invention, the composition for forming a resin film formed on a substrate is heated. Examples of the apparatus used for heating include a heating plate, a baking oven, and the like.

The heating temperature must be 500 ° C or less. When the heating temperature is 500 ° C or higher, the obtained resin film becomes brittle, and it is not possible to produce a resin film suitable for use in a display substrate.

In addition, when the heat resistance of the obtained resin film is increased, the heating temperature of the composition for forming a resin film after coating is carried out to increase the temperature stepwise, and it is preferably heated, for example, at 50 ° C to 100 ° C. After ~2 hours, the heating temperature is increased stepwise, and finally heated at over 375 ° C ~ 500 ° C for 30 minutes ~ 4 hours.

In particular, it is preferred to heat the coated resin film forming composition by the following steps of increasing the heating temperature in a stepwise manner, that is, preferably, the following steps are carried out as follows: heating at 50 ° C to 100 ° C for 5 minutes. After ~2 hours, heat at 100 °C ~ 200 °C for 5 minutes to 2 hours, then over 200 °C ~ 375 °C for 5 minutes to 2 hours, and finally over 375 °C Heating at ~500 °C for 30 minutes to 4 hours, especially by the following steps to increase the heating temperature in the following order: heating at 50 ° C ~ 100 ° C for 5 minutes ~ 2 hours, after exceeding 100 ° C ~ 200 ° C Heat for 5 minutes to 2 hours, then heat at 200 ° C ~ 375 ° C for 5 minutes to 2 hours, then heat over 375 ° C ~ 425 ° C for 15 minutes to 2 hours, and finally heated at more than 425 ° C ~ 500 ° C for 15 minutes ~ 2 hour.

The atmosphere during heating may be in air or an inert gas, and may be under normal pressure or under reduced pressure.

The thickness of the resin film, especially when used as a substrate for a flexible display, is usually about 1 to 60 μm, preferably about 5 to 50 μm, and the thickness of the coating film before heating can be adjusted to form a resin film having a desired thickness.

The above-described manufacturing method is particularly suitable for producing a resin film which satisfies various conditions necessary for a substrate film as a display substrate, and the resin film obtained by the method is most suitable for use as a substrate film as a display substrate (also The flexible display substrate).

[Examples]

The invention is described in more detail in the following examples, but the invention is not limited to the following examples. The dianhydride, the diamine, and the terminal blocking material (anhydride) are all manufactured by Tokyo Chemical Industry Co., Ltd.

[1] Abbreviations used in the examples Dianhydride

PMDA: pyrethic acid dianhydride

BPDA: 4,4'-diphthalic anhydride

BzDA: 3,3',4,4'-diphenyl ketone tetracarboxylic dianhydride

ODPA: 4,4'-oxydiphthalic anhydride

PSDA: 3,3',4,4'-diphenylphosphonium tetracarboxylic dianhydride

<Diamine>

HAB: 3,3'-dihydroxybenzidine

PDA: p-phenylenediamine

<End Blocking Agent>

PEPA: 4-phenylethynyl phthalic anhydride

4EPA: 4-ethynyl phthalic anhydride

Solvent

NMP: N-methyl-2-pyrrolidone

[2] Determination of number average molecular weight and weight average molecular weight

The weight average molecular weight (hereinafter abbreviated as Mw) and the molecular weight distribution of the polymer were obtained by using a GPC apparatus (Shodex [registered trademark], column SB803HQ and SB804HQ) manufactured by JASCO Corporation, and a dimethyl group as a dissolution solvent. The methotrexate was set to have a flow rate of 0.9 mL/min, and was measured at a column temperature of 40 °C. Mw is a value converted to polystyrene.

[3] Manufacture of a resin film-forming composition <Example 1>

HAB 34.3 g (0.16 mol) was dissolved in NMP 720 g, BPDA 45.7 g (0.16 mol) was added, and the mixture was reacted at 23 ° C for 24 hours under a nitrogen atmosphere. The obtained polymer had a Mw of 151,800 and a molecular weight distribution of 2.5. This reaction solution is used as a resin film forming composition as it is for the production of a resin film.

<Example 2>

1.58 g (0.0073 mol) of HAB was dissolved in 21.3 g of NMP, 2.10 g (0.0071 mol) of BPDA was added, and after stirring at 23 ° C for 1 hour under a nitrogen atmosphere, 0.0724 g (0.00029 mol) of PEPA was added, further Reaction for 23 hours. The obtained polymer had an Mw of 94,800 and a molecular weight distribution of 2.1. This reaction solution is used as a resin film forming composition as it is for the production of a resin film.

<Example 3>

HAB 2.08g (0.0096 mol) was dissolved in NMP 20.0g, BPDA 2.69g (0.0091 mol) was added, and after stirring at 23 ° C for 1 hour under nitrogen atmosphere, PEPA 0.238 g (0.00096 mol) was added, further Reaction for 23 hours. The obtained polymer had a Mw of 38,500 and a molecular weight distribution of 1.9. This reaction solution is used as a resin film forming composition as it is for the production of a resin film.

<Example 4>

Dissolve HAB 2.11g (0.0097 mol) in NMP 20.0g, add After adding 2.72 g (0.0093 mol) of BPDA, the mixture was stirred at 23 ° C for 1 hour under a nitrogen atmosphere, and then 4 EPA 0.168 g (0.00097 mol) was added, and further reacted for 23 hours. The obtained polymer had a Mw of 38,100 and a molecular weight distribution of 1.9. This reaction solution is used as a resin film forming composition as it is for the production of a resin film.

<Comparative Example 1>

0.955 g (0.0088 mol) of PDA was dissolved in 21.5 g of NMP, 2.55 g (0.0086 mol) of BPDA was added, and the reaction was carried out at 23 ° C for 24 hours under a nitrogen atmosphere. The obtained polymer had a Mw of 37,000 and a molecular weight distribution of 2.8. This reaction solution is used as a resin film forming composition as it is for the production of a resin film.

<Comparative Example 2>

1.26 g (0.0058 mol) of HAB was dissolved in 22.5 g of NMP, and 1.24 g (0.0057 mol) of PMDA was added, and then reacted at 23 ° C for 24 hours under a nitrogen atmosphere. The obtained polymer had a Mw of 146,300 and a molecular weight distribution of 2.7. This reaction solution is used as a resin film forming composition as it is for the production of a resin film.

<Comparative Example 3>

1.52 g of HAB (0.0070 mol) was dissolved in 21.3 g of NMP, and 2.23 g (0.0069 mol) of BzDA was added, and the mixture was reacted at 23 ° C for 24 hours under a nitrogen atmosphere. The obtained polymer has a Mw of 126,000 and a molecular weight The distribution is 2.6. This reaction solution is used as a resin film forming composition as it is for the production of a resin film.

<Comparative Example 4>

1.56 g (0.0072 mol) of HAB was dissolved in 21.3 g of NMP, 2.19 g (0.0071 mol) of ODPA was added, and the reaction was carried out at 23 ° C for 24 hours under a nitrogen atmosphere. The obtained polymer had an Mw of 54,800 and a molecular weight distribution of 3.5. This reaction solution is used as a resin film forming composition as it is for the production of a resin film.

<Comparative Example 5>

1.43 g (0.0066 mol) of HAB was dissolved in 21.3 g of NMP, 2.32 g (0.0065 mol) of PSDA was added, and the reaction was carried out at 23 ° C for 24 hours under a nitrogen atmosphere. The obtained polymer had an Mw of 65,400 and a molecular weight distribution of 2.8. This reaction solution is used as a resin film forming composition as it is for the production of a resin film.

<Comparative Example 6>

The resin film-forming composition (varnish) obtained in Example 1 was heated at 170 ° C for 3 hours in a nitrogen atmosphere to precipitate an insoluble matter, and a uniform varnish suitable for obtaining a film having high flatness could not be obtained.

[4] Manufacture of resin film <Example 5>

The resin film-forming composition obtained in Example 1 was applied onto a glass substrate by a sheet, baked in air at 90 ° C for 20 minutes, and then subjected to 120 ° C for 20 minutes in the following manner, followed by 180 °C for 20 minutes, followed by 240 ° C for 20 minutes, followed by 300 ° C for 20 minutes, followed by 400 ° C for 60 minutes, under nitrogen atmosphere, while gradually increasing the temperature while baking, to make a resin film.

<Examples 6 to 8>

A resin film was produced in the same manner as in Example 5 except that the resin film-forming composition obtained in Examples 2 to 4 was used instead of the resin film-forming composition obtained in Example 1.

<Examples 9 to 12>

A resin film was produced by the same method as in Examples 5 to 8 except that the heat treatment was performed at 400 ° C for 60 minutes, and further heat treatment was performed at 450 ° C for 60 minutes.

<Comparative Examples 7 to 11>

A resin film was produced in the same manner as in Example 5 except that the resin film-forming composition obtained in Comparative Examples 1 to 5 was used instead of the resin film-forming composition obtained in Example 1.

<Comparative Example 12>

A resin film was produced by the same method as in Comparative Example 7, except that the heat treatment was performed at 400 ° C for 60 minutes, and further heat treatment was performed at 450 ° C for 60 minutes.

[5] Evaluation of heat resistance, peelability and flexibility of resin film

The resin films of Examples 5 to 12 and Comparative Examples 7 to 12 were evaluated by the following methods. The film was produced separately for each evaluation.

The results are shown in Table 1. The film thickness is a resin film used for evaluation of peelability and flexibility. Further, with respect to the resin film of Comparative Example 8, only the peelability evaluation and the softness evaluation were performed.

<Evaluation of peelability and softness>

The ease of peeling when peeling each resin film from a glass substrate was evaluated. The peeling property was evaluated by forming a long slit on the resin film formed on the glass substrate using a cutting blade, and confirming whether the long film was easily peeled off from the glass substrate to cut the knife. When the film is inserted between the film and the glass substrate, the film is not easily caught and the film is easily peeled off, and the other is defective.

Further, the softness of the resin film after peeling was evaluated. The evaluation of the softness is carried out by visually confirming the ease of destruction (cracking, cracking, breakage, etc.) of the film when the resin film after peeling is bent or stretched by hand, to bend by hand Those who are not broken when they are folded 90 degrees or stretched are good, and others are bad.

<Heat resistance evaluation>

The 5% by mass reduction temperature (Td 5% (° C.)) of each resin film was measured. The measurement was carried out using TG-DTA (manufactured by Bruker AXS, TG/DTA2000SA) (heating rate: from 50 ° C to 800 ° C per 10 ° C per minute).

As shown in the first table, the resin films of Comparative Examples 7 and 12 did not have appropriate tightness with the glass substrate, and good results were not obtained in the evaluation of the peeling property. In particular, the resin film of Comparative Example 7 was naturally peeled off from the glass substrate, and was not suitable for use as a resin film for a substrate in a process of a display.

Further, the resin films of Comparative Examples 8 to 11 exhibited good peeling properties, but were easily broken when the resin film was bent by hand, and the resin films of Comparative Examples 7 and 9 to 12 were compared with Example 5 ~12 resin film phase The heat resistance is poor.

On the other hand, the resin films of Examples 5 to 12 exhibited not only good peelability and moderate flexibility, but also high heat resistance. In particular, the 5% by weight reduction temperature of the resin films of Examples 9 to 12 was around 620 ° C, and as a result, the films had extremely high heat resistance.

From the results of the above examples, the production method of the present invention according to the use of a composition for forming a resin film containing polyamic acid having a weight average molecular weight of 5,000 or more represented by the above formula (1-1) can be known. A resin film which is particularly suitable for use in a display substrate can be obtained, and the resin film-forming composition is particularly suitable for the production of a resin film used as a display substrate.

Claims (9)

A method for producing a resin film for a display substrate, comprising: coating a resin film forming composition containing a polyamine acid having a weight average molecular weight of 5,000 or more represented by the following formula (1-1) on a substrate and heating Stage, [In the formula (1-1), Ar ¹ represents a tetravalent group represented by the following formula (2) or (3), and Ar ² represents a formula (4-1), a formula (4-2) or a formula: (5) represents the base of the 4 valence, m represents the number of repeating units and is a positive integer] (In equations (2) and (3), the star mark and the wavy line mark indicate the bond key, one of the two key bonds with the star mark, and the two key bonds with the wavy line mark. 1 line and carboxyl bond) (In equations (4-1), (4-2), and (5), the star mark and the wavy line mark represent the bond key, and one of the two key bonds with the star mark is attached with a wave. One of the two bond bonds of the line mark is bonded to the hydroxyl group). The manufacturing method of claim 1, wherein the polylysine is represented by the following formula (1-2), In the formula (1-2), X represents a divalent group represented by any one of the following formulas (6) to (8), and Ar ¹ , Ar ² and m represent the same as defined above; [In the formulae (6) to (8), R ¹ to R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and Y represents 1 represented by the following formula (9) or (10); The base of the valence, n represents the number of Y bonded to the aromatic ring and is an integer of 1 to 3, and the star symbol indicates a bonding bond; (In the formulae (9) and (10), R ⁵ to R ⁸ each independently represent a hydrogen atom or an aryl group having 6 to 20 carbon atoms, and a star symbol indicates a bonding bond)]}. The manufacturing method of claim 1 or 2, wherein the aforementioned substrate is a glass substrate. The manufacturing method according to any one of claims 1 to 3, wherein the heating is performed by increasing the heating temperature stepwise. The manufacturing method of claim 4, wherein the step of gradually increasing the heating temperature is performed in the following steps: heating at 50 ° C to 100 ° C for 5 minutes to 2 hours, and heating at over 100 ° C to 200 ° C for 5 minutes to 2 hours. , heated at more than 200 ° C ~ 375 ° C for 5 minutes to 2 hours, and then heated at more than 375 ° C ~ 500 ° C for 30 minutes ~ 4 hours. A resin film for a display substrate obtained by the production method according to any one of claims 1 to 5. A flexible display substrate comprising the resin film for a display substrate according to claim 6. A resin film-forming composition for a display substrate, comprising a polyglycine having a weight average molecular weight of 5,000 or more represented by the following formula (1-1), [In the formula (1-1), Ar ¹ represents a tetravalent group represented by the following formula (2) or (3), and Ar ² represents a formula (4-1), a formula (4-2) or a formula: (5) represents the base of the 4 valence, m represents the number of repeating units and is a positive integer] (In equations (2) and (3), the star mark and the wavy line mark indicate the bond key, one of the two key bonds with the star mark, and the two key bonds with the wavy line mark. 1 line and carboxyl bond) (In equations (4-1), (4-2), and (5), the star mark and the wavy line mark represent the bond key, and one of the two key bonds with the star mark is attached with a wave. One of the two bond bonds of the line mark is bonded to the hydroxyl group). The composition for forming a resin film for a display substrate according to claim 8, wherein the polylysine is represented by the following formula (1-2). In the formula (1-2), X represents a divalent group represented by any one of the following formulas (6) to (8), and Ar ¹ , Ar ² and m represent the same as defined above; [In the formulae (6) to (8), R ¹ to R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and Y represents 1 represented by the following formula (9) or (10); The base of the valence, n represents the number of Y bonded to the aromatic ring and is an integer of 1 to 3, and the star symbol indicates a bonding bond; (In the formulae (9) and (10), R ⁵ to R ⁸ each independently represent a hydrogen atom or an aryl group having 6 to 20 carbon atoms, and a star symbol indicates a bonding bond)]}.