Coating agent composition

Abstract

To provide a coating agent composition that enables uniform film formation of an inorganic film formed from polysilazane on an organic resin film, without occurrence of defects such as pinholes.SOLUTION: A coating agent composition comprises (A) a polysilazane compound having a repeating structure represented by the following formula (1), Formula (1): -(Si(R1)2-NH)n- (wherein R1 independently represents a hydrogen atom, or an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, and n is an integer of 2 to 20,000), (B) a surfactant represented by the following formula (2) (wherein R2 independently represents a hydrogen atom, or an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an ω-hydroxyalkyl group having 1 to 12 carbon atoms, or an ω-alkoxyalkyl group having 2 to 12 carbon atoms), and (C) an organic solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a coating composition. [Background technology]

[0002] Advanced electronic materials, such as organic light-emitting diodes (OLEDs), solid-state batteries, and perovskite solar cells, are not simply improvements on conventional technologies; they are comprised of entirely new materials and concepts. These technologies have been newly conceived and developed in recent years to overcome the potential performance limitations and vulnerabilities inherent in conventional technologies. Specifically, conventional LCD monitors, whose light-emitting elements are made of inorganic materials, cannot be folded even when enlarged, and their heavy weight makes them virtually unportable. To address this issue, organic light-emitting diodes (OLEDs) using organic fluorescent materials were developed to provide flexibility and lightness. Furthermore, conventional secondary batteries using liquid electrolytes have faced problems with electrolyte leakage due to aging and fires caused by overcharging. To address these issues, solid-state batteries using non-flammable solid electrolytes have been developed.

[0003] As in the examples above, cutting-edge electronic materials use completely different structures and materials to solve potential problems that conventional products have. As a result, they also have several issues not present in conventional products, one of the most common and important issues being water resistance. The new materials used in these cutting-edge electronic materials are generally very vulnerable to water, and in order to ensure durability over a certain period of time, they require high gas barrier performance with low water vapor permeability at room temperature. However, conventional technologies have the following problems:

[0004] To achieve this high gas barrier performance, a method of sandwiching and sealing between glass plates has been proposed (Patent Document 1). This method is advantageous in terms of cost because it allows sealing at a relatively low cost, but it cannot be used in devices such as organic electroluminescence (EL) and perovskite solar cells, which have the advantages of flexibility and light weight, because it eliminates these advantages. Another method of sealing using metal foil, etc., is also possible, but metal foil is not optically transparent, so it cannot be used in devices such as organic electroluminescence (EL) and perovskite solar cells, which require light to pass through both inside and outside the device.

[0005] A method of laminating an organic film that has been treated with a high gas barrier instead of glass or metal foil has also been proposed (Patent Document 2). In this method, an inorganic film such as SiO2 or Si3N4 is formed by CVD on a film that is optically transparent and flexible, such as polyethylene terephthalate (PET). This is preferable in terms of properties because it ensures optical transparency and flexibility compared to direct sealing with inorganic glass or metal. However, a problem is that CVD film formation of multiple layers is required to achieve high gas barrier performance, resulting in very high costs. Furthermore, while thin films such as SiO2 and Si3N4 formed by CVD film formation have a certain degree of flexibility, they are weak against strong bending and have durability issues.

[0006] To solve this problem, the use of polysilazane instead of CVD film formation has been proposed (Patent Document 3). Polysilazane is a solvent-soluble polymer before curing, and after curing, it forms an inorganic film of SiO2 or SiOxNy, making it suitable for wet coating. Compared to dry coating (CVD), wet coating has the advantage of being able to cover particles and other contaminants from the top of the film, resulting in higher yields. Furthermore, CVD requires a vacuum to form a high-gas barrier film, necessitating batch production, which increases costs. Atmospheric-pressure CVD does not require reduced pressure, shortening film formation time compared to low-pressure CVD, but it is prone to dust generation and is not suitable for forming high-gas barrier films. From the perspectives of production cost and yield, forming inorganic films using polysilazane is preferable. However, with wet coating, film uniformity is highly dependent on the wettability between the coating liquid and the substrate, so film defects such as pinholes must be considered. Since film defects must be minimized, particularly for high-gas barrier films, prior surface modification treatments such as Ar plasma treatment are often used on the substrate, or multiple applications of the polysilazane solution coating liquid are often employed. However, although these measures have some effect, the effect is limited and is still insufficient for forming a high gas barrier film.

[0007] In order to solve the above problems, there is a need for a coating composition that can uniformly form an inorganic film of polysilazane on an organic resin film without causing defects or the like. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2020-88077 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-87815 [Patent Document 3] Japanese Patent Application Publication No. 2018-177859 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made to solve the above problems, and an object of the present invention is to provide a coating composition that can uniformly form an inorganic film of polysilazane on an organic resin film without generating defects such as pinholes. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a coating composition having the following characteristics. (A) A polysilazane compound having a repeating structure represented by the following formula (1): [ka] (In the formula, R 1 are independently a hydrogen atom or a group selected from an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms, and n is an integer of 2 to 20,000. (B) a surfactant represented by the following formula (2): [ka] (In the formula, R 2 are independently a hydrogen atom or a group selected from an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an ω-hydroxyalkyl group having 1 to 12 carbon atoms, and an ω-alkoxyalkyl group having 2 to 12 carbon atoms. (C) Organic solvent A coating composition comprising:

[0011] Such a coating composition makes it possible to form a highly uniform coating film without defects such as pinholes.

[0012] The polysilazane compound of the component (A) is preferably perhydropolysilazane.

[0013] Such a coating composition can provide a coating film that has excellent gas barrier properties after curing.

[0014] R in formula (2) of the component (B) 2 is preferably a hydrogen atom.

[0015] With such a coating agent composition, component (B) does not react with the polysilazane compound used to cause gelation or precipitates, and it is possible to form a highly uniform coating film.

[0016] The organic solvent of the component (C) preferably contains an ether compound or an ester compound.

[0017] Such a coating composition provides a composition that is excellent in terms of the solubility of the polysilazane compound and the surfactant, and the wettability to inorganic and organic materials. [Effects of the Invention]

[0018] As described above, in the coating composition of the present invention, the surfactant (B) does not react with the polysilazane compound to cause gelation or precipitate formation. Furthermore, the coating composition is excellent in terms of the solubility of the polysilazane compound and the surfactant, as well as wettability to inorganic and organic materials. Furthermore, the coating composition is capable of forming a highly uniform coating film free of defects such as pinholes thanks to the surfactant that does not degrade the polysilazane. Films having a film formed from the coating composition of the present invention can be obtained with higher gas barrier performance than conventional films. [Brief explanation of the drawings]

[0019] [Figure 1] 10 is an image of the white light interference film thickness measurement in Example 4. [Figure 2] 10 is an image of the white light interference film thickness measurement of Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0020] As described above, there has been a demand for a highly uniform coating film that is free from defects such as pinholes, and a film with high gas barrier properties as a result.

[0021] As a result of extensive research into the above-mentioned problems, the present inventors have found that a coating agent composition containing a polysilazane compound having a repeating structural unit with a specific structure, a surfactant with a structure represented by formula (2), and an organic solvent can provide a coating film with high uniformity and no defects such as pinholes, and have completed the present invention.

[0022] The present invention will be described in detail below, but the present invention is not limited thereto.

[0023] That is, the present invention is a coating agent composition comprising the following (A), (B), and (C):

[0024] [(A) Polysilazane compound] (A) A polysilazane compound having a repeating structure represented by the following formula (1): [ka] (In the formula, R 1 are independently a hydrogen atom or a group selected from an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms, and n is an integer of 2 to 20,000.

[0025] R 1 Examples of the alkyl group include a hydrogen atom, aliphatic hydrocarbon groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and cyclohexyl groups, aromatic hydrocarbon groups such as phenyl, tolyl, benzyl, and naphthyl groups, and alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy groups. Of these, a hydrogen atom is preferred.

[0026] Furthermore, n is an integer of 2 to 20,000, and preferably an integer of 60 to 10,000. If n is greater than 20,000, the solubility in organic solvents decreases, which is not preferred.

[0027] Examples of component (A) include modified polysilazanes such as perhydropolysilazane, methylpolysilazane, dimethylpolysilazane, phenylpolysilazane, methylphenylpolysilazane, and vinylpolysilazane. The component (A) may contain one or a mixture of two or more polysilazanes selected from these, or a polysilazane copolymer consisting of two or more polysilazane structures. Among these, perhydropolysilazane is most preferred from the viewpoint of gas barrier properties after curing.

[0028] Furthermore, from the viewpoint of solubility in (C) organic solvents described below and workability during application, the polysilazane compound preferably has a weight-average molecular weight in the range of 100 to 1,000,000, preferably 1,000 to 500,000, and more preferably 3,000 to 100,000. A weight-average molecular weight of 100 or more is preferred because it is less likely to volatilize during drying and curing of the organic solvent, eliminating the risk of deterioration in the quality of the coating film. Furthermore, a weight-average molecular weight of 1,000,000 or less is preferred because it provides good solubility in organic solvents. In the present invention, the weight-average molecular weight refers to a value measured under the following conditions using polystyrene as a standard substance.

[0029] [Measurement conditions] Developing solvent: tetrahydrofuran (THF) Flow rate: 0.6mL / min Detector: UV detector Column: TSK Guardcolumn SuperH-L TSKgel SuperMultiporeHZ-M(4.6mmI.D.×15cm×4) (All manufactured by Tosoh Corporation) Column temperature: 40℃ Sample injection volume: 20 μL (0.5 wt% THF solution)

[0030] [(B) Surfactant] (B) a surfactant represented by the following formula (2): [ka] (In the formula, R 2 are independently a hydrogen atom or a group selected from an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an ω-hydroxyalkyl group having 1 to 12 carbon atoms, and an ω-alkoxyalkyl group having 2 to 12 carbon atoms.

[0031] The surfactant used in the coating composition must be one that does not react with the polysilazane compound to form gels or precipitates. Because polysilazane compounds react easily with highly polar substances, ionic anionic surfactants and cationic surfactants are almost unusable. Nonionic surfactants are less likely to react with polysilazane, but when polysilazane is dispersed in water or an alcohol solvent, or when solvents remain as residual components during manufacturing, the polysilazane may react with the solvent. The component (B) of the present invention, represented by formula (2), can be stably dispersed when added to the polysilazane compound, and can also improve gas barrier properties by improving wettability and eliminating air bubbles during coating.

[0032] R in equation (2) 2 Specific examples of include a hydrogen atom, aliphatic hydrocarbon groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a cyclohexyl group, ω-hydroxyalkyl groups such as an ω-hydroxymethyl group, an ω-hydroxyethyl group, an ω-hydroxypropyl group, and an ω-hydroxybutyl group, and ω-alkoxyalkyl groups such as an ω-methoxymethyl group, an ω-ethoxymethyl group, an ω-ethoxyethyl group, an ω-propoxyethyl group, and an ω-butoxyethyl group.

[0033] Specific examples of the component (B) of the present invention include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-dimethoxy, 2,4,7,9-tetramethyl-5-decyne-4,7-di(ethylene glycol), 2,4,7,9-tetramethyl-5-decyne-4,7-di(ethylene glycol monomethyl ether), etc. Among these, from the viewpoint of compatibility with the polysilazane compound (A) and the organic solvent (C), R 2 corresponds to a hydrogen atom, 2,4,7,9-tetramethyl-5-decyne-4,7-diol is preferred.

[0034] The amount of surfactant represented by formula (2) added can be set arbitrarily depending on the desired wettability and defoaming properties, but the amount of surfactant added is preferably within the range of 0.01 to 5 mass % of the total coating composition, and more preferably within the range of 0.1 to 1 mass %. If the amount of surfactant represented by formula (2) added is 0.01% or more, it is preferable in that the effects of wettability and defoaming are fully exhibited. If it is 5% or less, it is preferable in that the gas barrier performance is not impaired.

[0035] [(C) Organic solvent] The organic solvent (C) of the present invention is intended to dilute the polysilazane compound (A) to a concentration suitable for coating, and can be used at any concentration relative to the polysilazane compound (A) and surfactant (B) used. Examples of the organic solvent include alkane compounds such as n-hexane, n-octane, and n-nonane; alkene compounds such as 1-octene, 1-nonene, and 1-decene; cycloalkane compounds such as cyclohexane, methylcyclohexane, and dimethylcyclohexane; ester compounds such as n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, isoamyl acetate, and ethyl caproate; and ether compounds such as diethyl ether, dibutyl ether, and ethylene glycol diethyl ether.

[0036] Among these, from the viewpoints of the solubility of the polysilazane compound and surfactant, and wettability to inorganic and organic materials, ether compounds or ester compounds are preferred, and dibutyl ether and butyl acetate are particularly preferred. The mixing ratio of the polysilazane compound to the solvent is preferably in the range of 0.1 / 99.9 to 20 / 80 by mass, more preferably 1 / 99 to 20 / 80, and even more preferably 2.5 / 97.5 to 20 / 80 by mass, which is preferable because storage stability and coatability are good and a thick coating can be achieved in one go.

[0037] [Additives] In addition to the components (A) to (C), the coating composition of the present invention may contain additives such as catalysts, fillers, UV absorbers, and antioxidants. Examples of additives include curing catalysts, fillers, UV absorbers, and UV scattering agents. Examples of curing catalysts include homogeneous or heterogeneous metal catalysts containing metal elements such as magnesium, aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, zinc, gallium, zirconium, niobium, palladium, and platinum; aliphatic amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, and tetramethylethylenediamine; aliphatic amino alcohols such as methylaminoethanol and dimethylaminoethanol; aromatic amines such as aniline, phenylethylamine, and toluidine; and heterocyclic amines such as pyrrolidine, piperidine, piperazine, pyrrole, pyrazole, imidazole, pyridine, pyridazine, and pyrimidine / pyrazine. The optimal curing catalyst can be selected depending on the curing method and temperature used.

[0038] Examples of fillers include reinforcing inorganic fillers such as fumed silica, fumed titanium dioxide, and fumed alumina, as well as inorganic fillers such as fused silica, alumina, zirconium oxide, calcium carbonate, calcium silicate, titanium dioxide, ferric oxide, and zinc oxide, and are added primarily for the purposes of mitigating cure shrinkage of the polysilazane compound, component (A), and for absorbing and scattering UV rays. The additives listed above are only examples, and any other additives may be added in any amount to impart desired properties.

[0039] [Base material] There are no particular limitations on the substrate as long as it can be coated with the coating composition of the present invention, but organic resin films are preferred for applications requiring flexibility, such as organic electroluminescence (EL) and perovskite solar cells. Examples of organic resins include general-purpose plastics such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyvinyl acetate (PVAc), polyurethane (PUR), polytetrafluoroethylene (PTFE), acrylonitrile butadiene styrene resin (ABS), and acrylic resin (PMMA); engineering plastics such as polyamide (PA), nylon, polycarbonate (PC), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT); and super-engineering plastics such as amorphous polyarylate (PAR), polysulfone (PSF), thermoplastic polyimide (PI), and polyetherimide (PEI). Among these, PET and PC, which are widely used industrially, are more preferred in terms of price, light transmittance, and processability.

[0040] The shape of the substrate is not particularly limited as long as it can be coated. For example, a film-like substrate is suitable as a film with excellent gas barrier properties. Furthermore, the substrate may be surface-treated before coating to remove dirt and adsorbed substances from the surface. Examples of surface treatment methods include argon plasma treatment, oxygen plasma treatment, ozone treatment, UV irradiation treatment, xenon excimer light irradiation treatment, blasting, and cleaning with a solvent. Furthermore, treatment with a primer or a surface treatment agent may also be performed.

[0041] [Method of using the coating composition] The coating composition of the present invention can be used as it is in the same manner as conventional coating compositions. Examples of methods for applying the coating composition to a substrate include roll coating using a chamber doctor coater, single-roll kiss coater, reverse kiss coater, bar coater, reverse roll coater, forward rotation roll coater, blade coater, knife coater, etc., spin coating, dispensing, dipping, spraying, transfer, slit coating, etc.

[0042] It is preferable to perform a drying process before curing the coating film of the coating composition applied by the above method in terms of post-curing properties, but this process may be omitted if the volatile components such as the solvent used have sufficiently evaporated by the time of the curing process. Furthermore, in the case of heat curing, the solvent evaporates before the polysilazane compound in the composition cures during the curing process, so this process may also be omitted. Conversely, if the curing process is performed before the solvent has sufficiently evaporated, the solvent will remain in the cured film, deteriorating the physical properties of the cured film. Furthermore, the solvent may evaporate when reheated, leading to poor appearance such as voids and cracks.

[0043] The most common methods for curing polysilazane coatings are heating or energy beam irradiation, but these methods are not necessarily limited to these. Furthermore, in the case of heat curing, the curing reaction temperature of polysilazane itself is so high that it is expected that the base thermoplastic resin would not be able to withstand it. Therefore, it is preferable to add a heat curing catalyst to polysilazane beforehand. Without a catalyst, the curing time is approximately one day at 150°C. With the addition of a catalyst, however, sufficient curing occurs in approximately one to three hours at 150°C, depending on the amount added. In the case of energy beam irradiation, a photoradical generator may be added beforehand, but curing proceeds satisfactorily even without it. In particular, polysilazane absorbs most of the irradiated light with a wavelength of 200 nm or less, such as xenon excimer light, allowing for rapid curing.

[0044] The thickness of the coating film is not particularly limited as long as it does not crack due to cure shrinkage of the polysilazane during curing, but is preferably in the range of 0.01 to 20 μm. A film thickness of 0.01 μm or more is preferred because it can fully exhibit the effect of suppressing oligomer precipitation by polysilazane, as well as gas barrier properties and solvent resistance. Furthermore, a film thickness of 20 μm or less is preferred because it has excellent film flexibility and is less likely to crack or peel when applied to a flexible substrate such as a thermoplastic resin film. Furthermore, the barrier film made of the cured polysilazane may be a single layer or a multi-layer film consisting of two or more layers.

[0045] The coating film of the present invention obtained in this manner has fewer film defects such as pinholes and has improved gas barrier properties compared to films formed from conventional coating compositions containing polysilazane. [Example]

[0046] EXAMPLES The present invention will be specifically explained below using examples and comparative examples, but the present invention is not limited to these. [Evaluation method]

[0047] The coating film performance was evaluated for the coated films prepared in the examples and comparative examples. [Water vapor permeability measurement] The water vapor permeability was measured using a Lyssy L80-5000 (Systech Instruments) water vapor permeability meter at 40°C and 90% RH according to JIS Z 0208:1976 cup method. 2 The water vapor permeability of 30 g / m or less was measured by the Mocon method in accordance with JIS K 7129B:2019. 2 Fail more than / day, 30g / m 2 Less than / day was rated as passing.

[0048] [Coating uniformity test] The surface roughness of the coating film and the number of pinholes were measured to evaluate the uniformity of the coating film. Surface roughness was measured using a laser microscope equipped with a white light interferometer, VK-X3000 (manufactured by Keyence Corporation). Measurements were performed on any surface measuring 1.0 mm x 1.5 mm using the white light interferometer method, and the arithmetic mean height Sa was calculated as an index of surface roughness. An Sa of less than 0.03 μm was evaluated as passing.

[0049] 1 and 2 show images of the white light interference film thickness measurement of Example 4 and Comparative Example 1. The parts indicated by numbers are pinholes.

[0050] Furthermore, on the measured surface, recesses with a depth of 80% or more of the coating film thickness were counted as pinholes, and the number of pinholes was counted. 50 or more pinholes were evaluated as failing, and less than 50 as passing.

[0051] [Example 1] A polysilazane solution was prepared using 5 parts perhydropolysilazane with a weight-average molecular weight of 8,600 and 95 parts dibutyl ether as a dilution solvent, to which 0.1 parts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol was added as a surfactant. This polysilazane solution was applied to a 75 μm-thick polyimide film using a bar coater so that the film thickness after drying would be 0.4 μm. The film was then heated and dried at 100°C for 10 minutes, and a Xe excimer was applied at 4,000 mJ / cm. 2The curing treatment was carried out by irradiating the film. The water vapor permeability of the cured film was measured and found to be 0.18 g / m 2 The arithmetic mean height Sa of the coating surface was 0.020 μm, and the number of pinholes in the measurement surface was 18.

[0052] [Example 2] A polysilazane solution was prepared using 5 parts perhydropolysilazane with a weight-average molecular weight of 8,600 and 95 parts dibutyl ether as a dilution solvent, to which 0.5 parts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol was added as a surfactant. This polysilazane solution was applied to a 75 μm-thick polyimide film using a bar coater so that the film thickness after drying would be 0.4 μm. The film was then heated and dried at 100°C for 10 minutes, and a Xe excimer was applied at 4,000 mJ / cm. 2 The film was irradiated with light and cured. The water vapor permeability of the cured film was measured and found to be 0.21 g / m 2 The arithmetic mean height Sa of the coating surface was 0.015 μm, and the number of pinholes in the measurement surface was 6.

[0053] [Example 3] A polysilazane solution was prepared using 5 parts perhydropolysilazane with a weight-average molecular weight of 8,600 and 95 parts dibutyl ether as a dilution solvent, to which 1 part of 2,4,7,9-tetramethyl-5-decyne-4,7-diol was added as a surfactant. This polysilazane solution was applied to a 75 μm-thick polyimide film using a bar coater so that the film thickness after drying would be 0.4 μm. The film was then heated and dried at 100°C for 10 minutes, and a Xe excimer was applied at 4,000 mJ / cm. 2 The film was irradiated with light and cured. The water vapor permeability of the cured film was measured and found to be 0.20 g / m 2 The arithmetic mean height Sa of the coating surface was 0.011 μm, and the number of pinholes in the measurement surface was 4.

[0054] [Example 4] A polysilazane solution was prepared using 5 parts perhydropolysilazane with a weight-average molecular weight of 8,600 and 95 parts dibutyl ether as a dilution solvent, to which 0.5 parts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol was added as a surfactant. This polysilazane solution was applied to a 75 μm-thick polyimide film using a bar coater so that the film thickness after drying would be 0.4 μm. The film was then heated and dried at 100°C for 10 minutes, and a Xe excimer was applied at 4,000 mJ / cm. 2 The film was then irradiated and cured. The same method was used to coat the film, resulting in a total of two laminated layers. The water vapor permeability of the cured film was measured and found to be 0.005 g / m 2 The arithmetic mean height Sa of the coating surface was 0.013 μm, and the number of pinholes in the measurement surface was 4.

[0055] [Example 5] A polysilazane solution was prepared using 2 parts perhydropolysilazane with a weight-average molecular weight of 8,600 and 98 parts dibutyl ether as a dilution solvent. 0.5 parts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol was added as a surfactant. This polysilazane solution was applied to a 75 μm-thick polyimide film using a bar coater so that the film thickness after drying would be 0.2 μm. The film was then dried by heating at 100°C for 10 minutes, and a Xe excimer was applied at 4,000 mJ / cm. 2 The film was then irradiated and cured. The same method was used to coat the film, resulting in a total of two laminated layers. The water vapor permeability of the cured film was measured and found to be 0.008 g / m 2 The arithmetic mean height Sa of the coating surface was 0.015 μm, and the number of pinholes in the measurement surface was 6.

[0056] [Example 6] A polysilazane solution was prepared using a blending ratio of 4 parts perhydropolysilazane with a weight-average molecular weight of 8,600, 1 part monomethylpolysilazane with a weight-average molecular weight of 3,500, and 95 parts dibutyl ether as a dilution solvent. 0.5 parts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol was added as a surfactant to the polysilazane solution. This polysilazane solution was applied to a 75 μm-thick polyimide film using a bar coater so that the film thickness after drying would be 0.5 μm. The film was then heated and dried at 100°C for 10 minutes, and Xe excimer was applied at 4,000 mJ / cm. 2 The film was then irradiated and cured. The same method was used to coat the film, resulting in a total of two laminated layers. The water vapor permeability of the cured film was measured and found to be 0.11 g / m 2 The arithmetic mean height Sa of the coating surface was 0.018 μm, and the number of pinholes in the measurement surface was 11.

[0057] [Example 7] A polysilazane solution was prepared using 5 parts of dimethylpolysilazane with a weight-average molecular weight of 2,400 and 95 parts of dibutyl ether as a dilution solvent, to which 0.5 parts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol was added as a surfactant. This polysilazane solution was applied to a 75 μm-thick polyimide film using a bar coater so that the film thickness after drying would be 0.4 μm. The film was then heated and dried at 100°C for 10 minutes, and Xe excimer was applied at 4,000 mJ / cm. 2 The curing treatment was carried out by irradiating the film. The water vapor permeability of the cured film was measured and found to be 20.8 g / m 2 The arithmetic mean height Sa of the coating surface was 0.021 μm, and the number of pinholes in the measurement surface was 10.

[0058] [Comparative Example 1] A polysilazane solution was prepared by mixing 5 parts of perhydropolysilazane with a weight-average molecular weight of 8,600 and 95 parts of dibutyl ether as a dilution solvent, and was applied to a 75 μm-thick polyimide film using a bar coater so that the film thickness after drying would be 0.4 μm. The film was then dried by heating at 100°C for 10 minutes, and Xe excimer was applied at 4,000 mJ / cm. 2 The film was irradiated with light and cured. The water vapor permeability of the cured film was measured and found to be 0.40 g / m 2 The arithmetic mean height Sa of the coating surface was 0.027 μm, and the number of pinholes in the measurement surface was 58.

[0059] Comparative Example 2 A polysilazane solution was prepared using 5 parts of perhydropolysilazane with a weight-average molecular weight of 8,600 and 95 parts of dibutyl ether as a dilution solvent, to which 0.5 parts of dialkyldimethylammonium chloride (trade name: Di-n-alkyldimethylammonium Chloride (mixture): manufactured by Tokyo Chemical Industry Co., Ltd.) was added as a surfactant. After the addition, the polysilazane solution gelled, so the evaluation was discontinued.

[0060] Comparative Example 3 A polysilazane solution was prepared using 5 parts perhydropolysilazane with a weight-average molecular weight of 8,600 and 95 parts dibutyl ether as a dilution solvent, to which 0.5 parts of 3,3-dimethyl-1-butyne was added as a surfactant. This polysilazane solution was applied to a 75 μm-thick polyimide film using a bar coater so that the film thickness after drying would be 0.5 μm. The film was then dried by heating at 100°C for 10 minutes, and Xe excimer was applied at 4,000 mJ / cm. 2 When the film was irradiated and cured, streaky irregularities were observed on the surface of the cured film, and the evaluation was discontinued.

[0061] Comparative Example 4 To a polysilazane solution prepared with a blending ratio of 5 parts perhydropolysilazane with a weight-average molecular weight of 8,600 and 95 parts dibutyl ether as a dilution solvent, 0.5 parts of 2-methyl-3-butyn-2-ol was added as a surfactant. After the addition, minute gel particles precipitated in the polysilazane solution, so the evaluation was discontinued.

[0062] Table 1 shows a summary of the examples and comparative examples. [Table 1] As can be seen from the results in Table 1, the coating film prepared from the surfactant-free polysilazane solution of Comparative Example 1 had 58 pinholes and failed to pass the uniformity of coating. In addition, the polysilazane solutions of Comparative Examples 2 to 4, which used surfactants other than the surfactant of the present invention, reacted with the polysilazane, making the polysilazane solution unstable, resulting in gel formation and uneven coating of the coating film, and thus failing to form a good coating film.

[0063] On the other hand, the coating films (Examples 1 to 7) prepared from the polysilazane solution of the present invention all passed the evaluations of arithmetic mean height Sa and pinholes, and uniform coating films were formed. Furthermore, these polyimide films have low water vapor permeability. It is presumed that the reduction in water vapor permeability is due to the effect of the surfactant of the present invention, which reduces pinholes and voids on the film during coating.

[0064] Furthermore, a comparison of Examples 6 and 7 with Examples 1 to 5 reveals that, with regard to the polysilazanes used in the present invention, those using perhydropolysilazane have low water vapor permeability and are particularly preferred.

[0065] From the above, it can be seen that the coating film using the polysilazane compound and surfactant of the present invention is uniform, has few pinholes, and has low gas barrier properties.

[0066] The present invention is not limited to the above-described embodiments, which are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that provides similar effects is included within the technical scope of the present invention.

[0067] This specification includes the following inventions. [1]: (A) a polysilazane compound having a repeating structure represented by the following formula (1): [ka] (In the formula, R 1 are independently a hydrogen atom or a group selected from an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms, and n is an integer of 2 to 20,000. (B) a surfactant represented by the following formula (2): [ka] (In the formula, R 2 are independently a hydrogen atom or a group selected from an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an ω-hydroxyalkyl group having 1 to 12 carbon atoms, and an ω-alkoxyalkyl group having 2 to 12 carbon atoms. (C) Organic solvent A coating composition comprising: [2]: The coating composition according to [1], wherein the polysilazane compound of component (A) is perhydropolysilazane. [3]: R in formula (2) of the component (B) 2 The coating composition according to [1] or [2], wherein is a hydrogen atom. [4]: The coating composition according to any one of [1] to [3], wherein the organic solvent of the component (C) contains an ether compound or an ester compound.

Claims

1. (A) A polysilazane compound having a repeating structure represented by the following formula (1): 【Chemistry 1】 (In the formula, R １ are independently a hydrogen atom or a group selected from an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms. Also, n is an integer of 2 to 20,000. (B) a surfactant represented by the following formula (2): 【Chemistry 2】 (In the formula, R ２ are independently a hydrogen atom or a group selected from an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an ω-hydroxyalkyl group having 1 to 12 carbon atoms, and an ω-alkoxyalkyl group having 2 to 12 carbon atoms. (C) Organic solvent A coating composition comprising:

2. 2. The coating composition according to claim 1, wherein the polysilazane compound of component (A) is perhydropolysilazane.

3. R in formula (2) of the component (B) ２ 2. The coating composition according to claim 1, wherein is a hydrogen atom.

4. 2. The coating composition according to claim 1, wherein the organic solvent of component (C) comprises an ether compound or an ester compound.

Images