Siloxane resin composition, cured film, and cured film substrate

Abstract

To provide a siloxane resin composition including at least (A) a siloxane resin, (B) a silica particle, and (C) a solvent where the total content of a fluoride ion, a chloride ion, a nitrate ion, a sulfate ion, and a phosphate ion in the composition is 0 ppm-100 ppm of the composition total.SOLUTION: A siloxane resin composition can inhibit condensation reaction of a siloxane resin overtime, and a viscosity when solved in a solvent is stable, as a result, a film thickness and a surface state is stable when coating, forming a film, and curing, and can make convexoconcave (a surface roughness) of a cured film surface small. Coagulation of a silica particle is inhibited, optical performances (an average light transmittance, and a haze value) of the cured film are good even when coating to form a film and curing after leaving for a prolong period of time, and convexoconcave (a surface roughness) of the cured film surface can be made small.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a siloxane resin composition containing silica particles, a cured film, and a cured film substrate. [Background technology]

[0002] Resin compositions containing polysiloxanes have excellent heat resistance, weather resistance, and transparency, and are therefore widely used in applications such as optical lenses, including microlens arrays for solid-state imaging devices, planarizing films for TFTs in liquid crystal and organic electroluminescent (EL) displays, protective films and insulating films for touch panels, anti-reflection films, optical filters, etc. Attempts have also been made to further improve performance by incorporating silica particles into resin compositions containing polysiloxanes.

[0003] For example, Patent Document 1 discloses an invention in which an alkoxysilane compound is hydrolyzed in the presence of silica particles and an acid catalyst such as hydrochloric acid, acetic acid, formic acid, nitric acid, oxalic acid, sulfuric acid, or phosphoric acid to obtain a silanol compound, and the silanol compound is then subjected to a condensation reaction to obtain a silica particle-containing polysiloxane. The invention of Patent Document 1 is characterized in that the condensation reaction of the silanol compound allows the formation of a cured film with improved pencil hardness, Young's modulus, and compressive stress, and reduces the difference in refractive index between the tempered glass substrate and the cured film, thereby reducing unevenness due to variations in the film thickness of the cured film.

[0004] Another invention, disclosed in Patent Document 2, involves hydrolyzing an alkoxysilane compound in the presence of an acid catalyst, such as one containing formic acid, acetic acid, or phosphoric acid, to obtain a siloxane resin, and then forming a glass-reinforcing material containing the siloxane resin and silica particles on at least one surface of a reinforced glass substrate to form a cured film having a thickness of 0.5 to 10 μm and a transmittance of 90% or more at a wavelength of 400 nm. The invention of Patent Document 2 is characterized by the fact that it can form a cured film made of a negative-type photosensitive siloxane resin with excellent moist heat resistance, and is suitable for use as a patternable, low-refractive index material for planarizing films in solid-state imaging devices. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-026360 [Patent Document 2] Japanese Patent Application Publication No. 2019-214492 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the invention of Patent Document 1, it is difficult to control the progress of the reaction in which an alkoxysilane compound is hydrolyzed in the presence of an acid catalyst to obtain a silanol compound, and the reaction in which the silanol compound is condensed. If the reaction state is not strictly controlled, the degree of polymerization of the resulting silica particle-containing polysiloxane will vary greatly, and when dissolved in an organic solvent, etc., the viscosity of the film-forming solution will be unstable, resulting in unstable film thickness and performance.

[0007] Furthermore, in the invention of Patent Document 2, when a glass-reinforced material containing a siloxane resin obtained by hydrolyzing an alkoxysilane compound and silica particles is left standing for a long period of time, the dispersed silica particles separate from the siloxane resin over time, and the silica particles aggregate due to the remaining acid catalyst, resulting in problems such as a decrease in the optical performance (average light transmittance and haze value) of the cured film obtained by applying the glass-reinforced material.

[0008] Furthermore, in the invention of Patent Document 1, there is a concern that the thickness of the film will become unstable, and in the invention of Patent Document 2, there is a concern that the particle size will vary due to aggregation of silica particles, resulting in increased surface irregularities (surface roughness) when the film is formed. This raises the issue that if a thin inorganic film is formed on top of this, defects such as pinholes and poor adhesion are likely to occur.

[0009] In order to solve these problems, an object of the present invention is to provide a siloxane resin composition containing silica particles and a solvent, in which the siloxane resin is synthesized using as little acid catalyst as is used in the prior art documents. [Means for solving the problem]

[0010] That is, the present invention is as follows. [1] A siloxane resin composition containing at least (A) a siloxane resin, (B) silica particles, and (C) a solvent, wherein the total content of fluoride ions, chloride ions, nitrate ions, sulfate ions, and phosphate ions in the composition is 0 ppm to 100 ppm of the entire composition. [2] The siloxane resin composition according to [1], wherein the content of each of fluoride ions, chloride ions, nitrate ions, sulfate ions, and phosphate ions in the composition is 0 ppm to 10 ppm based on the total composition. [3] The siloxane resin composition according to [1] or [2], wherein the content of any one of trifluoroacetate ions, methanesulfonate ions, trifluoromethanesulfonate ions, benzenesulfonate ions, and p-toluenesulfonate ions in the composition is 100 to 10,000 ppm of the total composition. [4] (B) The siloxane resin composition according to any one of [1] to [3], wherein the average particle size of the silica particles is 1 to 80 nm. [5] (A) The siloxane resin composition according to any one of [1] to [4], wherein the mass average molecular weight of the siloxane resin is 1,000 or more and 15,000 or less. [6] (A) The siloxane resin composition according to any one of [1] to [5], wherein the siloxane resin has a phenyl group, and the content of the phenyl group in the siloxane resin is 20 to 60 mol % relative to Si atoms. [7] The siloxane resin composition according to any one of [1] to [6], wherein (A) the siloxane resin has a radical polymerizable group and further contains a photopolymerization initiator. [8] A cured film formed from the siloxane resin composition according to any one of [1] to [7], wherein the cured film has a thickness of 2 μm and an average light transmittance at a wavelength of 400 nm of 93% or more. [9] The cured film according to [8], which has a haze value per 1 μm of film thickness of less than 1.2%.

[10] The cured film according to [8] or [9], having a surface roughness of less than 7.5 nm.

[11] A cured film substrate comprising a substrate on which the cured film according to any one of [8] to

[10] is formed. [Effects of the Invention]

[0011] The siloxane resin composition of the present invention can suppress the condensation reaction of the siloxane resin over time, and has a relatively stable viscosity when dissolved in a solvent. As a result, when the composition is applied to form a film and then cured, the film thickness and surface condition are stabilized, and the unevenness (surface roughness) of the cured film surface can be reduced.

[0012] Furthermore, the siloxane resin composition of the present invention suppresses aggregation of silica particles, and even when applied to form a film and cured after leaving it for a long period of time, the optical properties (average light transmittance and haze value) of the cured film are good, and the surface irregularities (surface roughness) of the cured film can be reduced. As a result, even when a thin film is formed on the surface of the cured film, a laminated film without defects such as pinholes or poor adhesion can be formed. DETAILED DESCRIPTION OF THE INVENTION

[0013] The siloxane resin composition of the present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be practiced with various modifications depending on the purpose and application. That is, the siloxane resin composition of the present invention is a siloxane resin composition containing (A) a siloxane resin, (B) silica particles, and (C) a solvent, and is characterized in that the contents of fluoride ions, chloride ions, nitrate ions, sulfate ions, and phosphate ions in the composition are each 0 ppm to 100 ppm.

[0014] <(A) Siloxane resin> (A) Siloxane resin is an intermediate substance between inorganic silica and organic silicone, synthesized by the hydrolysis and dehydration condensation of alkoxysilane compounds, and has the property of forming three-dimensional structures such as random structures and cage structures through siloxane bonds. Therefore, it can easily form a strong resin film with a high molecular weight.

[0015] From the viewpoint of coatability, the mass average molecular weight (Mn) of the (A) siloxane resin is preferably 1,000 or more, more preferably 2,000 or more. From the viewpoint of developability, the Mn of the (A) siloxane resin is preferably 15,000 or less, more preferably 12,000 or less. Here, the Mn of the (A) siloxane resin in the present invention refers to the polystyrene equivalent value measured by gel permeation chromatography (GPC).

[0016] The (A) siloxane resin preferably contains a repeating unit having three siloxane bonds represented by the following formula (1) and / or a repeating unit having four siloxane bonds represented by the following formula (2). By containing a repeating unit represented by the following formula (1) and / or a repeating unit represented by the following formula (2), the crosslink density after film formation is increased, and the degree of hardening of the film can be improved.

[0017] [ka]

[0018] [ka]

[0019] In the above formulas (1) and (2), R, X, and Y may be the same or different and represent a hydrogen atom, a halogen atom, or an organic group having 1 to 20 carbon atoms. Examples of the organic group having 1 to 20 carbon atoms include an alkyl group, an aryl group, an amino group, an amide group, a carboxyl group, a carbonyl group, and an ester group. A single siloxane resin may contain two or more types of repeating units having different R, X, and Y.

[0020] R is preferably a phenyl group. That is, it is preferable that the (A) siloxane resin has a phenyl group. The inclusion of a phenyl group stabilizes the siloxane, stabilizes the viscosity of the composition, improves compatibility with other additives, and improves the optical properties of the resulting cured film.

[0021] The organic group having 1 to 20 carbon atoms represented by R may be partially substituted with a radically polymerizable group. That is, it is preferable that the (A) siloxane resin has a radically polymerizable group. In this case, in the cured product of the resin composition, the radically polymerizable group may be radically polymerized. The inclusion of a radically polymerizable group has the effect of enabling the formation of a stronger film by a crosslinking reaction with additives, etc.

[0022] Examples of the radically polymerizable group include unsaturated organic groups such as a vinyl group, an α-methylvinyl group, an acryloyl group, a methacryloyl group, an alkenyl group, a styryl group, etc. Among these radically polymerizable organic groups, those having an acryloyl group or a methacryloyl group are preferred because they allow the curing reaction in the film to proceed smoothly and provide good crack resistance.

[0023] The method for producing a siloxane resin having repeating units represented by the above formulas (1) and (2) is not particularly limited, but examples include a production method in which an alkoxysilane compound is hydrolyzed to substitute the alkoxide with a hydroxyl group to form a silanol, and then the silanolized hydroxyl group is polymerized by a dehydration condensation reaction and distilled off to obtain the resin.

[0024] Examples of the alkoxysilane compound include tetrafunctional alkoxysilane compounds such as tetramethoxysilane and tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, methyltributoxysilane, methyltriphenoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, diethyldimethoxysilane, n-propyltrimethoxysilane, and isopropyltrimethoxysilane. alkyl-containing alkoxysilane compounds such as diisopropyldimethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, diisobutyldimethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, and n-decyltriethoxysilane; trifluoromethylsilane; fluorine-containing alkoxysilane compounds such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxy ...ethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane Examples of alkoxysilane compounds include epoxy group- or oxetane group-containing alkoxysilane compounds such as 3-ethyl-3-{[3-(trimethoxysilyl)propoxy]methyl}oxetane, and aryl group-containing alkoxysilane compounds such as phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, tolylmethoxysilane, o-xylyltrimethoxysilane, and naphthyltrimethoxysilane.

[0025] Among these, alkoxysilane compounds having a phenyl group are preferably used, and the resulting siloxane resin preferably has a phenyl group. The content of phenyl groups in the siloxane resin is preferably 20 to 60 mol% relative to Si atoms. When the phenyl group content is within this range, the viscosity of the resulting siloxane resin composition is stable. A more preferred content of phenyl groups is a ratio of 30 to 55 mol% relative to Si atoms. When the content is within this range, the viscosity of the siloxane resin composition is more stable, compatibility with other additives is improved, and the optical properties of the resulting cured film are also improved.

[0026] In addition, alkoxysilane compounds having an unsaturated organic group in the molecule are also preferably used. Examples thereof include γ-acryloylpropyltrimethoxysilane, γ-acryloylpropyltriethoxysilane, γ-methacryloylpropyltrimethoxysilane, γ-methacryloylpropyltriethoxysilane, γ-acryloylpropylmethyldimethoxysilane, γ-acryloylpropylmethyldiethoxysilane, γ-methacryloylpropylmethyldimethoxysilane, γ-methacryloylpropylmethyldiethoxysilane, p-styryltrimethoxysilane, p-styryltriethoxysilane, p-styrylmethyldimethoxysilane, p-styrylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, allyltrimethoxysilane, and allylmethyldimethoxysilane. When an alkoxysilane compound having an unsaturated organic group in the molecule is used, the content of the unsaturated organic group in the siloxane resin is preferably 10 to 50 mol % relative to the Si atom.

[0027] Alternatively, an alkoxysilane compound having a succinic acid group in the molecule may be used. The succinic acid group has the function of improving adhesion to glass substrates. Examples of alkoxysilane compounds having a succinic acid group in the molecule include 3-trimethoxysilylpropyl succinic anhydride, 3-triethoxysilylpropyl succinic anhydride, and 3-methyldimethoxysilylpropyl succinic anhydride. When an alkoxysilane compound having a succinic acid group is used, the content of the succinic acid group in the siloxane resin is preferably 5 to 20 mol % relative to the Si atom.

[0028] The hydrolysis and dehydration condensation reaction of the alkoxysilane compound is preferably carried out in a solvent. The solvent can be appropriately selected taking into consideration the stability, wettability, volatility, etc. of the resin composition. Furthermore, if a solvent is produced by the hydrolysis reaction, it is also possible to carry out the hydrolysis without a solvent. When used in a resin composition, it is also preferable to adjust the resin composition to an appropriate concentration by adding a solvent after the hydrolysis and dehydration condensation reaction is completed. Furthermore, after the hydrolysis and dehydration condensation reaction, it is also possible to distill and remove all or part of the produced alcohol, etc. by heating and / or under reduced pressure, and then add a suitable solvent.

[0029] When a solvent is used in the hydrolysis and dehydration condensation reactions, there are no particular limitations on the solvent, but typically the same solvent as the (C) solvent described below is used. The amount of solvent added is preferably 20 parts by mass or more, more preferably 40 parts by mass or more, per 100 parts by mass of the total alkoxysilane compounds, from the viewpoint of suppressing gel formation due to overreaction. On the other hand, the amount of solvent added is preferably 500 parts by mass or less, more preferably 200 parts by mass or less, per 100 parts by mass of the total alkoxysilane compounds, from the viewpoint of more rapidly progressing the hydrolysis and dehydration condensation reactions.

[0030] The hydrolysis and dehydration condensation reaction of alkoxysilane compound is preferably carried out in the presence of a catalyst.As the catalyst, use hydrochloric acid, acetic acid, formic acid, nitric acid, oxalic acid, hydrochloric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, polycarboxylic acid or its anhydride or other acid, or organic salts such as methanesulfonic acid pyridine salt, ethanesulfonic acid pyridine salt, propanesulfonic acid pyridine salt, benzenesulfonic acid pyridine salt, p-toluenesulfonic acid pyridine salt, xylenesulfonic acid pyridine salt, trifluoromethanesulfonic acid pyridine salt, trifluoroethanesulfonic acid pyridine salt, trifluoropropanesulfonic acid pyridine salt, trifluoroacetic acid pyridine salt, p-toluenesulfonic acid 2,4,6-trimethylpyridine salt, p-toluenesulfonic acid aniline salt, tetramethylammonium p-toluenesulfonate, tetraethylammonium p-toluenesulfonate, tetramethylammonium hydroxide, tetraethylammonium hydroxide or other organic salts. Among these, organic salts are preferably used because it is preferable that the composition contains as few fluoride ions, chloride ions, nitrate ions, sulfate ions, and phosphate ions as possible, as will be described later.

[0031] The amount of catalyst added is preferably 0.1 to 5 parts by weight per 100 parts by weight of the alkoxysilane compound. By setting the amount of catalyst within the above range, the hydrolysis and dehydration condensation reactions can be more efficiently carried out.

[0032] A preferred method of hydrolysis involves, for example, adding an aqueous solution of the catalyst to a mixture of a solvent and an alkoxysilane compound over a period of 1 to 60 minutes, followed by heating for 1 to 120 minutes at room temperature to 70° C. The amount of water added is preferably 1.0 to 4.0 moles per mole of the alkoxysilane compound.

[0033] Examples of methods for the dehydration condensation reaction include heating the silanol compound solution obtained by the hydrolysis reaction of the alkoxysilane compound as is. The heating temperature is preferably 50°C or higher and the boiling point of the solvent or lower, and the heating time is preferably 1 to 100 hours. Depending on the purpose, after the dehydration condensation reaction, an appropriate amount of the produced alcohol may be distilled and removed under heating and / or reduced pressure, and then a suitable solvent may be added.

[0034] <(B) Silica particles> (B) silica particles not only improve film strength and viscosity, but also promote the progress of the hydrolysis reaction and dehydration condensation reaction of siloxane resin. (B) silica particles can be obtained by a method such as hydrolysis and polycondensation of one or more alkoxysilane compounds in the presence of water, an organic solvent, and a base (preferably ammonia). (B) silica particles dispersed in an organic solvent can be obtained by replacing the water, which is the aqueous silica particle dispersion medium, with an organic solvent.

[0035] (B) For silica particles, the dispersion medium can be replaced by adding an organic solvent to aqueous silica particles and then removing the water by distillation or other means. Depending on the type of solvent, a lower alcohol may be added to partially esterify the surface of the silica particles. From the viewpoint of compatibility with other additives such as siloxane resins and polymerization initiators, particles dispersed in an organic solvent are preferred.

[0036] Specific examples of (B) silica particles include IPA-ST, which uses isopropanol as a dispersion medium and has an average particle diameter of 12 nm; MIBK-ST, which uses methyl isobutyl ketone as a dispersion medium and has an average particle diameter of 12 nm; PGM-AC-3140Y, which uses propylene glycol monomethyl ether as a dispersion medium and has an average particle diameter of 22 nm; IPA-ST-L, which uses isopropanol as a dispersion medium and has an average particle diameter of 45 nm; and IPA-ST-ZL, which uses isopropanol as a dispersion medium and has an average particle diameter of 80 nm (all of which are trade names, manufactured by Nissan Chemical Industries, Ltd.).

[0037] Other products include OSCAR 101 with an average particle size of 12 nm, which uses gamma-butyrolactone as a dispersion medium; OSCAR 105 with an average particle size of 60 nm, which uses gamma-butyrolactone as a dispersion medium; OSCAR 106 with an average particle size of 120 nm, which uses diacetone alcohol as a dispersion medium; Cataloid-S with an average particle size of 5 to 80 nm, which uses water as a dispersion medium (all trade names, manufactured by Catalysts and Chemical Industries Co., Ltd.); Quatrone PL-2L-PGME with an average particle size of 16 nm, which uses propylene glycol monomethyl ether as a dispersion medium; Quatrone PL-1-PGME with an average particle size of 12 nm; and Quatrone PL-2L with an average particle size of 17 nm, which uses gamma-butyrolactone as a dispersion medium. Examples of such dispersion media include Quatrone PL-BL, Quatrone PL-1-BL with an average particle size of 13 nm, Quatrone PL-2L-DAA with an average particle size of 17 nm using diacetone alcohol as a dispersion medium, Quatrone PL-1-DAA with an average particle size of 13 nm, Quatrone PL-2L, GP-2L, and Quatrone PL-1 with an average particle size of 18 to 20 nm using water as a dispersion medium (all trade names manufactured by Fuso Chemical Co., Ltd.), Silica (SiO2) SG-SO100 with an average particle size of 100 nm (trade name manufactured by Kyoritsu Material Co., Ltd.), and Reolosil with an average particle size of 5 to 50 nm (trade name manufactured by Tokuyama Corporation).

[0038] These (B) silica particles may be used alone or in combination of two or more. Furthermore, it is preferable that the surface of the (B) silica particles used has a reactive group, which facilitates bonding between the (A) siloxane resin and the (B) silica particles and increases the strength of the film. Examples of the reactive group include hydroxyl groups such as silanol, alcohol, and phenol, vinyl groups, acrylic groups, ethynyl groups, epoxy groups, and amino groups.

[0039] The content of (B) silica particles is preferably 10% by weight or more, more preferably 20% by weight or more, of the solid content in order to further improve the film strength, while the content of silica particles is preferably 50% by weight or less, more preferably 40% by weight or less, of the solid content in order to improve the average light transmittance of the cured film and the adhesion to the substrate.

[0040] It is also preferable that the (B) silica particles are chemically bonded to a portion of the (A) siloxane resin to form a homogenized structure. Homogenized (B) silica particles improve the hardness of the cured film, making it possible to prevent the (B) silica particles from precipitating from the cured film. "Homogenized" here refers to the reaction of the silica component of the (B) silica particles with a portion of the (A) siloxane resin, resulting in the (B) silica particles being incorporated into the (A) siloxane resin at a constant density.

[0041] This state can be confirmed by observing the boundary between the (B) silica particles and the siloxane resin using a transmission electron microscope (hereinafter referred to as TEM). When homogenized, the boundary between the (B) silica particles and the (A) siloxane resin is not visible in TEM observation. Homogenization is also preferred because a homogenized system has higher adhesion than a system in which the same amount of (B) silica particles is added to the (A) siloxane resin.

[0042] As a method for producing the (A) siloxane resin of the present invention containing (B) silica particles chemically bonded to at least a portion thereof, there can be mentioned a method in which a solvent, water, and optionally a catalyst are added to an alkoxysilane compound to hydrolyze the alkoxysilane compound, and the (B) silica particles and the hydrolyzed alkoxysilane compound are partially condensed to obtain the resin.

[0043] The (B) silica particles may be added together with the alkoxysilane compound from the beginning, or after the hydrolysis and condensation polymerization of the alkoxysilane compound is completed to form the (A) siloxane resin, or they may be added during the hydrolysis and condensation polymerization of the alkoxysilane compound.

[0044] The average particle size of (B) silica particles is preferably 1 to 80 nm. If the average particle size is smaller than 1 nm, they will be prone to aggregation even with the catalyst specifications of the present invention. If the average particle size is larger than 80 nm, they will deteriorate over time and be prone to peeling off from the cured film. A more preferred size is 10 nm to 45 nm. A size of 10 nm or more will fully exhibit performance and effects such as improved film strength, while a size of 45 nm or less will suppress light scattering and improve the optical properties of the cured film.

[0045] (B) The average particle size of silica particles can be determined by dynamic light scattering. Specifically, a dispersion liquid containing 10 to 30% by weight of silica particles is irradiated with light having a wavelength of 780 nm from a semiconductor laser, the scattered light is measured, and then frequency analysis is performed using the FFT-heterodyne method to determine the average particle size.

[0046] <(C) Solvent> The (C) solvent adjusts the viscosity of the resin composition to a range suitable for application and improves application uniformity. Examples of solvents include alcohols such as water, ethanol, propanol, and diacetone alcohol; glycols such as ethylene glycol and propylene glycol; ethers such as ethylene glycol monomethyl ether and propylene glycol monoethyl ether; ketones such as methyl ethyl ketone and cyclopentanone; amides such as dimethylformamide and dimethylacetamide; acetates such as ethylene glycol monoethyl ether acetate and butyl acetate; aromatic or aliphatic hydrocarbons such as toluene, xylene, and cyclohexane; γ-butyrolactone, N-methyl-2-pyrrolidone, and dimethyl sulfoxide. Two or more of these may be used.

[0047] From the viewpoint of coatability, it is preferable to combine a solvent having a boiling point of 150° C. or higher and 250° C. or lower under atmospheric pressure with a solvent having a boiling point of 150° C. or lower. For example, diacetone alcohol can be combined as a solvent having a boiling point of 150° C. or higher and 250° C. or lower under atmospheric pressure with propylene glycol monomethyl ether as a solvent having a boiling point of 150° C. or lower.

[0048] The content of the solvent may be set arbitrarily depending on the application method, etc. For example, when forming a film by spin coating, the content of the solvent in the composition of the present invention is generally 50% by mass or more and 95% by mass or less. For example, when forming a film by spin coating, the content of the solvent in the composition of the present invention is generally 50% by mass or more and 95% by mass or less.

[0049] The composition of the present invention is characterized in that the total content of fluoride ions, chloride ions, nitrate ions, sulfate ions, and phosphate ions in the composition is 0 ppm to 100 ppm relative to the total composition. If the content of these inorganic acid ions in the composition exceeds 100 ppm, it becomes difficult to control the progress of the reaction, the viscosity of the composition becomes unstable, and the thickness and performance of the film become unstable.

[0050] Furthermore, even if the total content of the composition is 100 ppm or less, the (B) silica particles may aggregate if left for a long period of time, which may lead to a decrease in the optical performance (average light transmittance and haze value) of the film formed. To maintain the optical performance, it is preferable that the total content of the composition be 10 ppm or less. That is, it is preferable that the total content of fluoride ions, chloride ions, nitrate ions, sulfate ions, and phosphate ions in the composition be 0 ppm to 10 ppm.

[0051] Furthermore, when a thin inorganic film is formed on top of a film of the composition, it is necessary to minimize the surface irregularities (surface roughness) of the film formed to prevent problems such as pinholes and poor adhesion. To achieve this, it is necessary to further suppress the aggregation of (B) silica particles, and it is more preferable that the content of these inorganic acid ions be made undetectable at 0 ppm.

[0052] Therefore, although inorganic acids have a useful function as catalysts for hydrolysis and dehydration condensation reactions, from the above viewpoint, the less inorganic acid ions they contain, the better. One method for keeping the content of these inorganic acid ions in the composition within the above range is to remove these inorganic acid ions or add an appropriate amount of a neutralizing agent that becomes a base ion after the hydrolysis or condensation reaction is completed, thereby eliminating these inorganic acid ions.

[0053] Examples of methods for removing these inorganic acid ions include treatment with water-washed ion exchange resins. Water-washing is a method in which a composition solution is diluted with an appropriate hydrophobic solvent, washed several times with water, and then the resulting organic layer is concentrated using an evaporator or the like. Treatment with ion exchange resins is a method in which a composition solution is brought into contact with an ion exchange resin to capture these inorganic acid ions.

[0054] Examples of a method for eliminating these inorganic acid ions by adding an appropriate amount of a neutralizing agent that becomes basic ions include a method in which an aqueous solution containing weakly basic ions such as aluminum hydroxide or ammonia is mixed with a lower alcohol, and the mixture is neutralized by adding the neutralizing agent dropwise in small amounts while stirring, and then the precipitated neutralized salt is removed by filtration.

[0055] However, although the method of removing or eliminating inorganic acid ions after the completion of the hydrolysis or condensation reaction is effective in preventing aggregation of the (B) silica particles when left to stand for a long period of time, it requires an extra step for the removal or elimination, and when the (B) silica particles are added after the completion of the hydrolysis or condensation reaction, problems such as the (B) silica particles not being uniformly dispersed in the (A) siloxane resin and separating over time are likely to occur.

[0056] Furthermore, when hydrolysis or condensation reactions are carried out after adding (B) silica particles, there is a problem in that some of the (B) silica particles aggregate before the reaction is completed, and once aggregated, the (B) silica particles do not easily return to their original state even if these inorganic acid ions are later completely removed or eliminated.

[0057] Therefore, in order to eliminate such concerns, it is preferable to use a different catalyst that does not generate these inorganic acid ions as a catalyst for the hydrolysis and dehydration condensation reaction, rather than using an inorganic acid that generates these inorganic acid ions. Examples of such catalysts include organic acid salts such as pyridine trifluoroacetate, pyridine methanesulfonate, pyridine trifluoromethanesulfonate, pyridine benzenesulfonate, pyridine p-toluenesulfonate, pyridine xylenesulfonate, pyridine trifluoroethanesulfonate, pyridine trifluoropropanesulfonate, 2,4,6-trimethylpyridine p-toluenesulfonate, aniline p-toluenesulfonate, tetramethylammonium p-toluenesulfonate, tetraethylammonium p-toluenesulfonate, tetramethylammonium hydroxide, and tetraethylammonium hydroxide.

[0058] When these organic acid salts are dissolved in a solvent, they generate organic acid ions such as trifluoroacetate ions, methanesulfonate ions, trifluoromethanesulfonate ions, benzenesulfonate ions, p-toluenesulfonate ions, xylenesulfonate ions, trifluoroethanesulfonate ions, and trifluoropropanesulfonate ions. When added in the same amount, these organic acid salts function less well as catalysts for hydrolysis and dehydration condensation reactions than the inorganic acids mentioned above. However, by increasing the amount added or reducing the amount of solvent added, the hydrolysis and dehydration condensation reactions can proceed satisfactorily.

[0059] Furthermore, the organic acid ions generated from these organic acid salts can be removed or neutralized after the completion of the hydrolysis or condensation reaction, allowing the production of compositions with good storage stability. Furthermore, the organic acid ions hardly induce aggregation of the (B) silica particles, and even when incorporated in large amounts, the aforementioned problems caused by aggregation of the (B) silica particles hardly occur.

[0060] Therefore, by adding a large amount of these organic acid salts, it is possible to compensate for the catalytic function of the hydrolysis and dehydration condensation reactions described above. In addition, since the amount added itself becomes large, there is also the advantage that by carefully setting and managing this amount, it becomes easier to control the hydrolysis and dehydration condensation reactions more delicately.

[0061] Among these organic acid salts, pyridine salts such as pyridine trifluoroacetate, pyridine methanesulfonate, pyridine trifluoromethanesulfonate, pyridine benzenesulfonate, and pyridine p-toluenesulfonate are preferred from the viewpoint of preventing discoloration when a film is formed from the composition and then cured.

[0062] The siloxane resin composition of the present invention preferably has a content of any one of trifluoroacetate ions, methanesulfonate ions, trifluoromethanesulfonate ions, benzenesulfonate ions, and p-toluenesulfonate ions in the composition of 100 to 10,000 ppm of the total composition.

[0063] By setting the content at 100 ppm or more of the total composition, the hydrolysis and dehydration condensation reactions of the alkoxysilane compound proceed efficiently, and by setting it at 10,000 ppm or less, the occurrence of problems due to aggregation of (B) silica particles can be suppressed. To ensure sufficient functionality of the hydrolysis and dehydration condensation reactions and more reliably suppress problems due to aggregation of (B) silica particles, the content is preferably set at 500 to 2,000 ppm of the total composition.

[0064] The organic acid salt acts as a catalyst to promote the dehydration condensation reaction of the silanol groups remaining in the (A) siloxane resin during the high-temperature heat treatment that occurs when forming the cured film. This promotes the reaction between the silanol groups in the (A) siloxane resin, increasing the crosslink density in the film and improving the degree of hardness of the cured film, as well as the solvent resistance of the film.

[0065] The organic salt can be used in two ways: one in which no inorganic acid is used at all from the beginning, and the organic salt is used as the sole catalyst for producing the (A) siloxane resin; a solution of the (A) siloxane resin is obtained without a catalyst removal step, and this solution is then used as the composition of the present invention; and another in which the inorganic acid is removed during the hydrolysis or condensation reaction of the (A) siloxane resin, and an organic salt is added instead, and the organic salt is used as a catalyst for the subsequent reaction. From the standpoint of process simplicity and prevention of problems caused by the (D) catalyst described above, the former use is preferred.

[0066] The organic acid salt may be commercially available or synthesized. For example, the organic acid salt may be obtained by stirring an organic acid capable of generating ions with dehydrated THF under nitrogen, adding an amine such as pyridine dropwise to the mixture while cooling with ice to neutralize the mixture and form a salt, filtering the formed salt, and drying it under vacuum.

[0067] The siloxane resin composition of the present invention may also contain a photopolymerizable compound. The photopolymerizable compound refers to a compound having two or more ethylenically unsaturated double bonds in the molecule. Examples of photopolymerizable compounds include glycol acrylates, glycol methacrylates, methylol acrylates, methylol methacrylates, butanediol acrylates, diol methacrylates, and diol diacrylates. Two or more of these may be contained. The content of the photopolymerizable compound is preferably 1% by mass or more and 50% by mass or less of the solid content.

[0068] Furthermore, the siloxane resin composition of the present invention may contain a photosensitizer to impart photosensitivity. When imparting negative photosensitivity, it is preferable to contain a photopolymerization initiator as the photosensitizer. When imparting positive photosensitivity, it is preferable to contain a quinone diazide compound as the photosensitizer.

[0069] Examples of photopolymerization initiators include α-aminoalkylphenone compounds, acylphosphine oxide compounds, oxime ester compounds, α-hydroxyketone compounds, benzophenone compounds, acetophenone compounds, and benzoic acid ester compounds. Among these, acylphosphine oxide compounds and oxime ester compounds are preferred from the viewpoints of sensitivity and transparency. Examples of acylphosphine oxide compounds include Omnirad TPOH and Omnirad 819 (manufactured by IGM). Examples of oxime ester compounds include Irgacure OXE-01, Irgacure OXE-02, Irgacure OXE-03, and Irgacure OXE-04 (manufactured by BASF), Adeka Arcles NCI-831E, Adeka Arcles NCI-930, and Adeka Arcles NCI-730 (manufactured by ADEKA). The content of the photopolymerization initiator is preferably 0.01% by mass or more and 10% by mass or less of the solid content.

[0070] The quinone diazide compound may be a compound in which a sulfonic acid of naphthoquinone diazide is bonded to a compound having a phenolic hydroxyl group via an ester bond. The content of the quinone diazide compound is preferably 0.5% by mass or more and 20% by mass or less of the solid content. Two or more of these may be contained.

[0071] Furthermore, the siloxane resin composition of the present invention may optionally contain an ultraviolet absorber, a polymerization inhibitor, a surfactant, an adhesion improver, a pigment, (B) nanoparticles other than silica particles, or (A) a resin other than a polysiloxane resin. Two or more of these may be contained. The content of these is preferably 0.1% by mass or more and 50% by mass or less of the solid content.

[0072] Examples of ultraviolet absorbers include benzotriazole-based, benzophenone-based, and triazine-based compounds. Examples of polymerization inhibitors include 4-methoxyphenol, 1,4-benzoquinone, and t-butylcatechol. Examples of surfactants include fluorine-based, silicone-based, polyalkylene oxide-based, and poly(meth)acrylate-based surfactants. Examples of adhesion improvers include alicyclic epoxy compounds and silane coupling agents.

[0073] Examples of pigments include white pigments such as titanium dioxide, zirconium oxide, zinc oxide, and barium sulfate, as well as colored pigments such as red, blue, black, green, yellow, purple, brown, orange, magenta, and cyan. (B) Examples of nanoparticles other than silica particles include magnesium fluoride particles, titania particles, and zirconia particles. (A) Examples of resins other than polysiloxane resins include polyimide, acrylic, polyester, and cardo resins.

[0074] Next, a cured film using the siloxane resin composition of the present invention will be described. The cured film of the present invention is preferably a cured film that remains in the final product, rather than a film that is removed during the manufacturing process, such as a resist film. The degree of curing of the cured film is not particularly limited, and it may be fully cured or partially cured. In particular, a cured film that has an average light transmittance of 93% or more at a wavelength of 400 nm when formed to a film thickness of 2 μm is preferred.

[0075] The reason for measuring at a wavelength of 400 nm is that as the average light transmittance at a wavelength of 400 nm decreases, the film turns yellow, making it easier to distinguish it as a transparent film. Therefore, if the average light transmittance at a wavelength of 400 nm is high, the film can function as a highly transparent and colorless glass-reinforced film. More preferably, the average light transmittance at a wavelength of 400 nm is 96% or more, making it possible to produce an ideal colorless and transparent glass-reinforced film that is indistinguishable from glass alone.

[0076] Furthermore, a cured film having a haze value of less than 1.2% per 1 μm of film thickness is preferred. A low haze value allows the film to function as a clear, reinforced glass film. More preferably, the haze value is less than 0.8% per 1 μm of film thickness, making it indistinguishable from glass alone and ideal for use as a reinforced cover glass film for displays.

[0077] Furthermore, a cured film having a surface roughness of less than 7.5 nm is preferred. In applications such as glass reinforcement films, coating films such as optical adjustment films such as silicon oxide and silicon nitride, ITO films, and metallic gloss multilayer films may be formed on the surface of the cured film of the present invention by methods such as vacuum deposition and sputtering. However, since these coating films are very thin, if the cured film surface has large irregularities (surface roughness), problems such as pinholes and poor adhesion are likely to occur.

[0078] More preferably, the surface roughness is less than 5 nm, making it possible to produce a tempered glass film with an ideal surface comparable to that of glass. Therefore, the cured film of the present invention can be suitably used not only as a protective film for touch panels and other hard coat films, but also as an insulating film for touch sensors, a planarizing film for TFTs in liquid crystal and organic EL displays, a protective film for metal wiring, an insulating film, an anti-reflection film, an optical filter, an overcoat for color filters, a pillar material, etc.

[0079] The thickness of the cured film of the present invention varies depending on the application, but is preferably 0.1 to 100 μm, more preferably 0.5 to 50 μm. The substrate for the cured film of the present invention is not particularly limited, and examples thereof include transparent glass such as soda glass, aluminosilicate glass, and zirconia glass, and transparent films such as acrylic, polycarbonate, polyester, cycloolefin, polyvinyl chloride, and polyvinyl alcohol.

[0080] Next, a method for forming the cured film of the present invention will be described. The cured film of the present invention can be formed, for example, by a film-forming step of applying the siloxane resin composition of the present invention to the substrate and drying it to obtain a dry film; The film is formed by a heating step in which the film is cured by heating. When an ionizing radiation curable component is contained, the film may be cured by an ionizing radiation irradiation step. When the cured film is to be patterned, an exposure step in which the dried film obtained after the film formation step is exposed to light and a development step may be added.

[0081] Examples of methods for applying the siloxane resin composition include gravure coating, die coating, roll coating, slit coating, spin coating, dip coating, lip coating, and spray coating. Examples of drying devices include hot air ovens and hot plates. The drying time is preferably 80 to 130°C, and the drying time is preferably 1 to 30 minutes.

[0082] The heating step is a step of heating and curing the film. Examples of heating devices include a hot plate and an oven. The heating temperature during the heating step is preferably 250°C or lower from the viewpoint of suppressing cracking in the heated film, and is preferably 100°C or higher from the viewpoint of the degree of hardness of the cured film. The heating time is preferably 15 minutes to 2 hours.

[0083] The ionizing radiation step is a step of curing the film with ionizing radiation. Examples of ionizing radiation include infrared, near-infrared, and ultraviolet. Examples of light sources include infrared LED lamps, ultraviolet LED lamps, mercury lamps, halogen lamps, and germicidal lamps. Irradiation conditions can be appropriately selected depending on the thickness of the dried film to be exposed. In the case of ultraviolet, the irradiation intensity is generally 1,000 to 10,000 mJ / cm. 2 The irradiation dose is preferably 1000 ppm or more.

[0084] The cured film substrate of the present invention is a cured film substrate in which the cured film of the present invention is formed on a substrate. [Example]

[0085] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. The names of the compounds used, for which abbreviations are used, are shown below. dpDMS: diphenyldimethoxysilane mPTMS: 3-methacryloxypropyltrimethoxysilane echPTMS: 3-(3,4-epoxycyclohexyl)propyltrimethoxysilane dmDMS: dimethyldimethoxysilane TMSPK: 3-trimethoxysilylpropylsuccinic anhydride TES; tetraethoxysilane MTMS; methyltrimethoxysilane PTSAPS: p-toluenesulfonic acid pyridine salt mSAPS: methanesulfonic acid pyridine salt TfOHPS: Trifluoromethanesulfonic acid pyridine salt TFAPS: Trifluoroacetic acid pyridine salt bSAP; benzenesulfonic acid pyridine salt PGMEA: Propylene glycol monomethyl ether acetate DAA: Diacetone alcohol BHT: dibutylhydroxytoluene.

[0086] <Measurement of solids concentration in siloxane resin solution> The solids concentration of the siloxane resin solution in the synthesis examples described below was determined by weighing 1.0 g of the polysiloxane solution into an aluminum cup, heating it on a hot plate at 250°C for 30 minutes to evaporate the liquid, weighing the mass of the solids remaining in the aluminum cup after heating, and calculating the solids concentration from the ratio to the mass before heating.

[0087] <Measurement of mass average molecular weight of siloxane resin> The mass average molecular weight of the siloxane resin in the synthesis examples described below was determined in polystyrene equivalent terms using the following apparatus and conditions. Apparatus: Waters GPC measurement device with RI detector (2695) Column: PLgel MIXED-C column (Polymer Laboratories, 300 mm) x 2 (connected in series) Measurement temperature: 40℃ Flow rate: 1mL / min Solvent: tetrahydrofuran (THF) 0.5% by mass solution Standard material: polystyrene Detection mode: RI.

[0088] <Measurement of phenyl group content in siloxane resin> The phenyl group content in the siloxane resin in the synthesis examples described below was determined by the following method. The siloxane resin solution was poured into a 10 mm diameter Teflon (registered trademark) NMR sample tube. 29 Si-NMR measurements were performed, and the content ratio of each repeating unit of the phenyl group was calculated from the ratio of the integral value of Si derived from a specific organosilane to the integral value of all Si derived from the organosilane. 29 The Si-NMR measurement conditions are as follows: Equipment: Nuclear magnetic resonance apparatus (JNM-GX270; manufactured by JEOL Ltd.) Measurement method: Gated decoupling method Measurement nuclear frequency: 53.6693MHz ( 29 Si nucleus) Spectral width: 20000Hz Pulse width: 12 μs (45° pulse) Pulse repetition time: 30.0 seconds Solvent: acetone-d6 Reference material: tetramethylsilane Measurement temperature: 23℃ Sample rotation speed: 0.0 Hz.

[0089] Synthesis Example 1: Preparation of Siloxane Resin Solution (A-1) A 1000 ml three-neck flask was charged with 200 g (0.82 mol) of dpDMS, 75 g (0.30 mol) of mPTMS, 22 g (0.09 mol) of echPTMS, 42 g (0.35 mol) of dmDMS, 45 g (0.17 mol) of TMSPK, 1.5 g of BHT, and 308 g of PGMEA, and an aqueous catalyst solution prepared by dissolving 3.9 g of PTSASP (1.0 mass % based on the total amount of charged monomers) in 77 g of water was added thereto with stirring at 40°C over 30 minutes.

[0090] The flask was then immersed in a 70°C oil bath and stirred for 60 minutes. The oil bath was then heated to 115°C over 30 minutes, and the mixture was then heated and stirred for 2 hours (internal temperature: 100-110°C), yielding a siloxane resin solution. During the temperature increase and heating and stirring, a gas mixture of 95% by volume of nitrogen and 5% by volume of oxygen was flowed at 0.05 L / min. A total of 174 g of by-products, methanol and water, was distilled during the reaction.

[0091] PGMEA was added to the resulting siloxane resin solution to adjust the solids concentration to 50% by mass, and siloxane resin solution (A-1) was obtained without removing the catalyst. The mass average molecular weight of the siloxane resin in the resulting siloxane resin solution (A-1) was 5,000. The phenyl group content in the siloxane resin of siloxane resin solution (A-1) was 47.5 mol% relative to Si atoms. By reacting with mPTMS, siloxane resin solution (A-1) possesses radical polymerizable groups.

[0092] <Synthesis Example 2: Preparation of Siloxane Resin Solution (A-2)> A siloxane resin solution (A-2) was obtained in the same manner as in Synthesis Example 1, except that a catalyst aqueous solution prepared by dissolving 3.9 g of mSAPS (1.0 mass % based on the charged monomers) in 77 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-2) was 3,500. The phenyl group content in the siloxane resin of siloxane resin solution (A-2) was 47.5 mol % relative to Si atoms.

[0093] Synthesis Example 3: Preparation of Siloxane Resin Solution (A-3) A siloxane resin solution (A-3) was obtained in the same manner as in Synthesis Example 1, except that a catalyst aqueous solution prepared by dissolving 3.9 g of TfOHPS (1.0 mass % based on the charged monomers) in 77 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-3) was 4,500. The content of phenyl groups in the siloxane resin in the siloxane resin solution (A-3) was 47.5 mol % based on Si atoms.

[0094] Synthesis Example 4: Preparation of Siloxane Resin Solution (A-4) A polysiloxane (A-3) solution was obtained in the same manner as in Synthesis Example 1, except that a catalyst aqueous solution prepared by dissolving 3.9 g of TFAPS (1.0 mass % based on the charged monomers) in 77 g of water was used. The mass average molecular weight of the obtained polysiloxane (A-4) was 4,000. The phenyl group content in the siloxane resin of the siloxane resin solution (A-4) was 47.5 mol % based on Si atoms.

[0095] Synthesis Example 5: Preparation of Siloxane Resin Solution (A-5) Siloxane resin solution (A-5) was obtained in the same manner as in Synthesis Example 1, except that a catalyst aqueous solution prepared by dissolving 3.9 g of bSAPS (1.0 mass % based on the charged monomers) in 77 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-5) was 4,500. The phenyl group content in the siloxane resin of siloxane resin solution (A-5) was 47.5 mol % relative to Si atoms.

[0096] Synthesis Example 6: Preparation of Siloxane Resin Solution (A-6) A siloxane resin solution (A-6) was obtained in the same manner as in Synthesis Example 1, except that a catalyst aqueous solution prepared by dissolving 0.43 g of PTSAPS (0.11 mass% based on the charged monomers) in 77 g of water was used and the amount of PGMEA added was 312 g. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-6) was 2,500. The phenyl group content in the siloxane resin of siloxane resin solution (A-6) was 47.5 mol% relative to Si atoms.

[0097] Synthesis Example 7: Preparation of Siloxane Resin Solution (A-7) A siloxane resin solution (A-7) was obtained in the same manner as in Synthesis Example 1, except that a catalyst aqueous solution prepared by dissolving 42.9 g of PTSAPS (11.0 mass % based on the charged monomers) in 210 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-7) was 10,000. The phenyl group content in the siloxane resin of siloxane resin solution (A-7) was 47.5 mol % based on Si atoms.

[0098] Synthesis Example 8: Preparation of Siloxane Resin Solution (A-8) A siloxane resin solution (A-8) was obtained in the same manner as in Synthesis Example 3, except that a catalyst aqueous solution prepared by dissolving 0.43 g of TfOHPS (0.11 mass % based on the charged monomers) in 77 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-8) was 2,000. The phenyl group content in the siloxane resin of siloxane resin solution (A-8) was 47.5 mol % based on Si atoms.

[0099] Synthesis Example 9: Preparation of Siloxane Resin Solution (A-9) A siloxane resin solution (A-9) was obtained in the same manner as in Synthesis Example 3, except that a catalyst aqueous solution prepared by dissolving 42.9 g of TfOHP (11.0 mass % based on the charged monomers) in 210 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-9) was 12,000. The phenyl group content in the siloxane resin of the siloxane resin solution (A-9) was 47.5 mol % based on Si atoms.

[0100] Synthesis Example 10: Preparation of Siloxane Resin Solution (A-10) A siloxane resin solution (A-10) was obtained in the same manner as in Synthesis Example 4, except that a catalyst aqueous solution prepared by dissolving 0.434 g of TFAPSS (0.11 mass % based on the charged monomers) in 77 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-10) was 1,500. The phenyl group content in the siloxane resin of siloxane resin solution (A-10) was 47.5 mol % based on Si atoms.

[0101] Synthesis Example 11 Preparation of Siloxane Resin Solution (A-11) A siloxane resin solution (A-11) was obtained in the same manner as in Synthesis Example 4, except that a catalyst aqueous solution prepared by dissolving 42.9 g of TFAPS (11.0 mass % based on the charged monomers) in 210 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-11) was 15,000. The phenyl group content in the siloxane resin of the siloxane resin solution (A-11) was 47.5 mol % based on Si atoms.

[0102] Synthesis Example 12: Preparation of Siloxane Resin Solution (A-12) A siloxane resin solution (A-12) was obtained in the same manner as in Synthesis Example 2, except that a catalyst aqueous solution prepared by dissolving 0.43 g of mSAPS (0.11% by mass relative to the charged monomers) in 77 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-12) was 1,000. The phenyl group content in the siloxane resin of siloxane resin solution (A-12) was 47.5 mol% relative to Si atoms.

[0103] Synthesis Example 13: Preparation of Siloxane Resin Solution (A-13) A siloxane resin solution (A-13) was obtained in the same manner as in Synthesis Example 2, except that a catalyst aqueous solution prepared by dissolving 42.9 g of mSAPS (11.0 mass % based on the charged monomers) in 210 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-13) was 13,000. The phenyl group content in the siloxane resin of siloxane resin solution (A-13) was 47.5 mol % based on Si atoms.

[0104] Synthesis Example 14: Preparation of Siloxane Resin Solution (A-14) A siloxane resin solution (A-14) was obtained in the same manner as in Synthesis Example 5, except that a catalyst aqueous solution prepared by dissolving 0.43 g of TFAPSS (0.11% by mass relative to the charged monomers) in 77 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-14) was 2,000. The phenyl group content in the siloxane resin of siloxane resin solution (A-14) was 47.5 mol% relative to Si atoms.

[0105] Synthesis Example 15: Preparation of Siloxane Resin Solution (A-15) A siloxane resin solution (A-15) was obtained in the same manner as in Synthesis Example 5, except that a catalyst aqueous solution prepared by dissolving 42.9 g of TFAPS (11.0 mass % based on the charged monomers) in 210 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-15) was 14,000. The phenyl group content in the siloxane resin of siloxane resin solution (A-15) was 47.5 mol % based on Si atoms.

[0106] Synthesis Example 16: Preparation of Siloxane Resin Solution (A-16) A siloxane resin solution (A-16) was obtained in the same manner as in Synthesis Example 1, except that 80 g (0.33 mol) of dpDMS, 100 g (0.40 mol) of mPTMS, 30 g (0.13 mol) of echPTMS, 60 g (0.52 mol) of dmDMS, and 65 g (0.25 mol) of TMSPK were charged into an initial 1000 ml three-neck flask. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-16) was 4,800. The phenyl group content in the siloxane resin of the siloxane resin solution (A-16) was 20.2 mol% relative to Si atoms. By reacting with mPTMS, the siloxane resin solution (A-16) possesses radical polymerizable groups.

[0107] Synthesis Example 17: Preparation of Siloxane Resin Solution (A-16) A siloxane resin solution (A-17) was obtained in the same manner as in Synthesis Example 16, except that a catalyst aqueous solution prepared by dissolving 3.9 g of mSAPS (1.0 mass % based on the charged monomers) in 77 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-17) was 3,300. The phenyl group content in the siloxane resin of siloxane resin solution (A-17) was 20.2 mol % relative to Si atoms.

[0108] Synthesis Example 18: Preparation of Siloxane Resin Solution (A-18) A siloxane resin solution (A-18) was obtained in the same manner as in Synthesis Example 16, except that a catalyst aqueous solution prepared by dissolving 3.9 g of TfOHPS (1.0 mass % based on the charged monomers) in 77 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-18) was 4,700. The phenyl group content in the siloxane resin of siloxane resin solution (A-18) was 20.2 mol % based on Si atoms.

[0109] Synthesis Example 19: Preparation of Siloxane Resin Solution (A-19) A siloxane resin solution (A-19) was obtained in the same manner as in Synthesis Example 16, except that a catalyst aqueous solution prepared by dissolving 3.9 g of TFAPS (1.0 mass % based on the charged monomers) in 77 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-19) was 3,900. The phenyl group content in the siloxane resin of siloxane resin solution (A-19) was 20.2 mol % relative to Si atoms.

[0110] Synthesis Example 20: Preparation of Siloxane Resin Solution (A-20) A siloxane resin solution (A-20) was obtained in the same manner as in Synthesis Example 16, except that a catalyst aqueous solution prepared by dissolving 3.9 g of bSAPS (1.0 mass % based on the charged monomers) in 77 g of water was used. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-20) was 4,400. The phenyl group content in the siloxane resin of siloxane resin solution (A-20) was 20.2 mol % based on Si atoms.

[0111] Synthesis Example 21: Preparation of Siloxane Resin Solution (A-21) A siloxane resin solution (A-21) was obtained in the same manner as in Synthesis Example 16, except that 300 g (1.23 mol) of dpDMS, 67 g (0.27 mol) of mPTMS, 20 g (0.08 mol) of echPTMS, 38 g (0.33 mol) of dmDMS, and 40 g (0.15 mol) of TMSPK were charged into an initial 1000 ml three-neck flask. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-21) was 5,200. The phenyl group content in the siloxane resin of the siloxane resin solution (A-21) was 59.7 mol% relative to Si atoms. By reacting with mPTMS, the siloxane resin solution (A-21) possesses radical polymerizable groups.

[0112] <Synthesis Examples 22 to 25: Preparation of Siloxane Resin Solutions (A-22) to (A-25)> Siloxane resin solutions (A-21) to (A-25) were obtained in the same manner as in Synthesis Examples 17 to 20, except that 300 g (1.23 mol) of dpDMS, 67 g (0.27 mol) of mPTMS, 20 g (0.08 mol) of echPTMS, 38 g (0.33 mol) of dmDMS, and 40 g (0.15 mol) of TMSPK were charged into an initial 1000 mL three-neck flask. The mass-average molecular weights of the siloxane resins in the resulting siloxane resin solutions (A-21) to (A-25) were 3,600, 5,100, 4,100, and 4,600, respectively. The phenyl group content of the siloxane resin in the siloxane resin solutions (A-22) to (A-25) was 59.7 mol% relative to Si atoms.

[0113] Synthesis Example 26: Preparation of Siloxane Resin Solution (A-26) A siloxane resin solution (A-26) was obtained in the same manner as in Synthesis Example 16, except that 160 g (0.66 mol) of dpDMS, 100 g (0.40 mol) of mPTMS, 30 g (0.13 mol) of echPTMS, 60 g (0.52 mol) of dmDMS, and 65 g (0.25 mol) of TMSPK were charged into an initial 1000 ml three-neck flask. The mass average molecular weight of the siloxane resin in the obtained siloxane resin solution (A-26) was 4,900. The phenyl group content in the siloxane resin of the siloxane resin solution (A-26) was 33.7 mol% relative to Si atoms. Note that by reacting with mPTMS, the siloxane resin solution (A-26) possesses radical polymerizable groups.

[0114] <Synthesis Examples 27 to 30: Preparation of Siloxane Resin Solutions (A-27) to (A-30)> Siloxane resin solutions (A-27) to (A-30) were obtained in the same manner as in Synthesis Examples 17 to 20, except that 160 g (0.66 mol) of dpDMS, 100 g (0.40 mol) of mPTMS, 30 g (0.13 mol) of echPTMS, 60 g (0.52 mol) of dmDMS, and 65 g (0.25 mol) of TMSPK were charged into an initial 1000 mL three-neck flask. The mass-average molecular weights of the siloxane resins in the resulting siloxane resin solutions (A-27) to (A-30) were 3,400, 4,500, 4,000, and 4,500, respectively. The phenyl group content of the siloxane resin in the siloxane resin solutions (A-27) to (A-30) was 33.7 mol% relative to Si atoms. By reacting with mPTMS, the siloxane resin solutions (A-27) to (A-30) have radical polymerizable groups.

[0115] <Synthesis Examples 31 to 35: Preparation of Siloxane Resin Solutions (A-31) to (A-35)> Siloxane resin solutions (A-31) to (A-35) were obtained in the same manner as in Synthesis Examples 1 to 5, except that an aqueous catalyst solution was used to which hydrofluoric acid, hydrochloric acid, nitric acid, and sulfuric acid were added so that each was 1 ppm, and phosphoric acid was added so that each was 6 ppm.

[0116] <Synthesis Examples 36 to 40: Preparation of Siloxane Resin Solutions (A-36) to (A-40)> Siloxane resin solutions (A-36) to (A-40) were obtained in the same manner as in Synthesis Examples 1 to 5, except that an aqueous catalyst solution to which phosphoric acid had been added so as to have a concentration of 10 ppm was used.

[0117] <Synthesis Examples 41 to 45: Preparation of Siloxane Resin Solutions (A-41) to (A-45)> Siloxane resin solutions (A-41) to (A-45) were obtained in the same manner as in Synthesis Examples 1 to 5, except that an aqueous catalyst solution was used to which hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid were each added at 2 ppm.

[0118] <Synthesis Examples 46 to 50: Preparation of Siloxane Resin Solutions (A-46) to (A-50)> Siloxane resin solutions (A-46) to (A-50) were obtained in the same manner as in Synthesis Examples 1 to 5, except that an aqueous catalyst solution was used to which hydrofluoric acid, hydrochloric acid, nitric acid, and sulfuric acid were added so that their concentrations were each 10 ppm, and phosphoric acid was added to 60 ppm.

[0119] Synthesis Examples 51 to 55: Preparation of Siloxane Resin Solutions (A-51) to (A-55) Siloxane resin solutions (A-51) to (A-55) were obtained in the same manner as in Synthesis Examples 1 to 5, except that an aqueous catalyst solution to which phosphoric acid had been added so that the concentration was 100 ppm was used.

[0120] <Synthesis Examples 56 to 60: Preparation of Siloxane Resin Solutions (A-56) to (A-60)> Siloxane resin solutions (A-56) to (A-60) were obtained in the same manner as in Synthesis Examples 1 to 5, except that an aqueous catalyst solution was used to which hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid were added so that each solution had a concentration of 20 ppm.

[0121] <Synthesis Examples 61 to 65: Preparation of Siloxane Resin Solutions (A-61) to (A-65)> Siloxane resin solutions (A-61) to (A-65) were obtained in the same manner as in Synthesis Examples 1 to 5, except that an aqueous catalyst solution was used to which hydrofluoric acid, hydrochloric acid, nitric acid, and sulfuric acid were added so that their concentrations were each 12 ppm, and phosphoric acid was added to 60 ppm.

[0122] <Synthesis Examples 66 to 70: Preparation of Siloxane Resin Solutions (A-66) to (A-70)> Siloxane resin solutions (A-66) to (A-70) were obtained in the same manner as in Synthesis Examples 1 to 5, except that an aqueous catalyst solution to which phosphoric acid had been added so that the concentration was 110 ppm was used.

[0123] <Synthesis Examples 71 to 75: Preparation of Siloxane Resin Solutions (A-71) to (A-75)> Siloxane resin solutions (A-71) to (A-75) were obtained in the same manner as in Synthesis Examples 1 to 5, except that an aqueous catalyst solution was used to which hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid were added so that each concentration was 22 ppm.

[0124] <Evaluation of Viscosity Stability of Siloxane Resin Composition> The viscosity (viscosity before storage) of the siloxane resin compositions obtained in each of the Examples and Comparative Examples described below was measured after preparation. Viscosity measurements were performed at 23°C using an E-type rotational viscometer (VISCOMETER TV-25, manufactured by TOKI SANGYO Co., Ltd.). The siloxane resin compositions obtained in each of the Examples and Comparative Examples were placed in a sealed container, and the viscosity was similarly measured after storage at room temperature (23°C) for 7 days and after storage at room temperature (40°C) for 3 days. The viscosity stability was evaluated for each storage condition based on the viscosity change rate ({|viscosity after storage - viscosity before storage| / viscosity before storage} × 100) according to the following criteria. A: Viscosity change rate less than 8% B: Viscosity change rate: 8% or more and less than 15% C: Viscosity change rate of 15% or more.

[0125] Example 1: Preparation of Siloxane Resin Composition (P-1) Under yellow light, 66 g of siloxane resin solution (A-1), 25 g of a 40 wt% dispersion of silica particles (average particle size 22 nm, product name "PGM-AC-3140Y" manufactured by Nissan Chemical Co., Ltd.), 1.0 g of "Irgacure" (registered trademark) OXE-01 manufactured by BASF Japan Ltd. (hereinafter "OXE-01") as a photopolymerization initiator, and 15 g of dipentaerythritol hexaacrylate (hereinafter "DPHA") as a photopolymerizable compound were dissolved in 69 g of solvent PGMEA and 100 g of DAA and stirred at room temperature. The resulting mixture was filtered to obtain siloxane resin composition (P-1).

[0126] <Examples 2 to 15: Preparation of Siloxane Resin Compositions (P-2) to (P-15)> Siloxane resin compositions (P-2) to (P-15) were obtained in the same manner as in Example 1, except that the siloxane resin solution (A-1) was replaced with siloxane resin solutions (A-2) to (A-15), respectively.

[0127] Example 16: Preparation of Siloxane Resin Compositions (P-16) to (P-20) A siloxane resin composition (P-16) was obtained in the same manner as in Example 1, except that 25 g of the 40 wt % dispersion of silica particles (average particle diameter 22 nm, product name "PGM-AC-3140Y" manufactured by Nissan Chemical Industries, Ltd.) was replaced with 33 g of a 30 wt % dispersion of silica particles (average particle diameter 12 nm, product name "IPA-ST" manufactured by Nissan Chemical Industries, Ltd.).

[0128] <Examples 17 to 20: Preparation of Siloxane Resin Compositions (P-17) to (P-20)> Siloxane resin compositions (P-17) to (P-20) were obtained in the same manner as in Example 16, except that the siloxane resin solution (A-1) was replaced with siloxane resin solutions (A-2) to (A-5), respectively.

[0129] Example 21: Preparation of Siloxane Resin Composition (P-21) A siloxane resin composition (P-21) was obtained in the same manner as in Example 1, except that 25 g of the 40 wt % dispersion of silica particles (average particle diameter 22 nm, product name "PGM-AC-3140Y" manufactured by Nissan Chemical Industries, Ltd.) was replaced with 33 g of a 30 wt % dispersion of silica particles (average particle diameter 45 nm, product name "IPA-ST-L" manufactured by Nissan Chemical Industries, Ltd.).

[0130] <Examples 22 to 25: Preparation of Siloxane Resin Compositions (P-22) to (P-25)> Siloxane resin compositions (P-22) to (P-25) were obtained in the same manner as in Example 21, except that the siloxane resin solution (A-1) was replaced with siloxane resin solutions (A-2) to (A-5), respectively.

[0131] <Example 26: Preparation of siloxane resin composition (P-26)> A siloxane resin composition (P-26) was obtained in the same manner as in Example 1, except that 25 g of the 40 wt % dispersion of silica particles (average particle diameter 22 nm, product name "PGM-AC-3140Y" manufactured by Nissan Chemical Industries, Ltd.) was replaced with 33 g of a 30 wt % dispersion of silica particles (average particle diameter 80 nm, product name "IPA-ST-ZL" manufactured by Nissan Chemical Industries, Ltd.).

[0132] <Examples 27 to 30: Preparation of Siloxane Resin Compositions (P-27) to (P-30)> Siloxane resin compositions (P-27) to (P-30) were obtained in the same manner as in Example 26, except that the siloxane resin solution (A-1) was replaced with siloxane resin solutions (A-2) to (A-5), respectively.

[0133] <Examples 31 to 75: Preparation of Siloxane Resin Compositions (P-31) to (P-75)> Siloxane resin compositions (P-31) to (P-75) were obtained in the same manner as in Example 1, except that the siloxane resin solution (A-1) was replaced with siloxane resin solutions (A-16) to (A-60), respectively.

[0134] <Comparative Examples 1 to 15: Preparation of Siloxane Resin Compositions (H-1) to (H-15)> Siloxane resin compositions (H-1) to (H-15) were obtained in the same manner as in Example 1, except that the siloxane resin solution (A-1) was replaced with siloxane resin solutions (A-61) to (A-75), respectively.

[0135] <Preparation of cured film> Siloxane resin compositions (P-1) to (P-75) obtained in each example and siloxane resin compositions (H-1) to (H-15) obtained in each comparative example were spin-coated onto bare glass substrates using a spin coater (product name 1H-360S, manufactured by Mikasa Co., Ltd.) and pre-baked at 100°C for 2 minutes using a hot plate (product name SCW-636, manufactured by Dainippon Screen Mfg. Co., Ltd.) to produce films. The films were then cured in air at 180°C for 1 hour using an oven (product name IHPS-222, manufactured by Espec Corp.) to produce cured films with a thickness of 2 μm. Film thickness stability, transmittance, haze, and surface roughness were evaluated using the following methods.

[0136] <Evaluation of thickness stability of cured film> The siloxane resin compositions obtained in each of the above examples and comparative examples immediately after preparation (before storage), and the siloxane resin compositions stored in sealed containers at room temperature (23°C) for 7 days and at room temperature (40°C) for 3 days were used to prepare cured films in the same manner as in the above cured film preparation procedure, and the film thickness stability was evaluated for each storage condition based on the film thickness change rate ({|film thickness prepared after storage - film thickness prepared before storage| / film thickness prepared before storage} × 100) according to the following criteria. A: Film thickness change rate less than 10% B: Film thickness change rate: 10% or more but less than 20% C: Film thickness change rate is 20% or more.

[0137] <Permeability evaluation of cured film> For the cured films obtained on the glass substrates using the siloxane resin compositions obtained in each of the Examples and Comparative Examples, the average light transmittance at a wavelength of 400 nm was measured using an ultraviolet-visible spectrophotometer UV-2600 (manufactured by Shimadzu Corporation) with the glass substrate used as a reference, and the transmittance of the cured films was evaluated according to the following criteria. A: Average light transmittance of 96% or more B: Average light transmittance of 93% or more and less than 96% C: Average light transmittance of 90% or more and less than 93% D: Average light transmittance less than 90%.

[0138] <Haze evaluation of cured film> For the cured films obtained on the glass substrates using the siloxane resin compositions obtained in each of the Examples and Comparative Examples, the haze value per μm of film thickness was measured using a haze meter NDH-2000 (manufactured by Nippon Denshoku Corporation) with the glass substrate used as a reference, and the haze of the cured films was evaluated according to the following criteria. A: Haze value less than 0.8% / μm B: Haze value 0.8% or more / μm, less than 1.2% / μm C: Haze value 1.2% or more / μm, less than 2.0% / μm D: Haze value 2.0% or more / μm.

[0139] <Evaluation of surface roughness of cured film> For the cured films obtained on the glass substrate using the siloxane resin compositions obtained in each of the Examples and Comparative Examples, the quantitative roughness value Ra (arithmetic mean roughness) of the cured film surface was measured using a scanning probe microscope NanoScope V Dimension Icon (manufactured by Bruker AXS), and the surface roughness of the cured film was evaluated according to the following criteria. [Measurement conditions] Tip: Silicon cantilever Scanning mode: Tapping mode Scanning range: 3 μm Scanning speed: 0.3Hz Measurement environment: Room temperature, in air A:Ra less than 5.0nm B: Ra 5.0nm or more and less than 7.5nm C:Ra7.5nm or more.

[0140] The evaluation results of Examples 1 to 75 and Comparative Examples 1 to 15 are shown together with the formulations of the siloxane resin compositions in Tables 1 to 6. ー , mSA ー , TfOH ー , bSA ー , PTSA ー , F - , Cl ー , NO3 ー , SO4 ー , PO3 ー represent trifluoroacetate ion, methanesulfonate ion, trifluoromethanesulfonate ion, benzenesulfonate ion, p-toluenesulfonate ion, fluoride ion, chloride ion, nitrate ion, sulfate ion, and phosphate ion, respectively.

[0141] The results in Tables 1 to 6 reveal that the most preferable cured films can be obtained from siloxane resin compositions that use trifluoroacetate ions, trifluoromethanesulfonate ions, or p-toluenesulfonate ions as catalyst ions, are free of fluoride ions, chloride ions, nitrate ions, sulfate ions, or phosphate ions, and are composed of a siloxane resin with a phenyl group content of 33 to 48% and a mass average molecular weight of 2,500 to 5,000, and have silica particles with an average particle size of 12 to 45 nm.

[0142] [Table 1]

[0143] [Table 2]

[0144] [Table 3]

[0145] [Table 4]

[0146] [Table 5]

[0147] [Table 6]

Claims

1. A siloxane resin composition containing at least (A) a siloxane resin, (B) silica particles, and (C) a solvent, wherein the total content of fluoride ions, chloride ions, nitrate ions, sulfate ions, and phosphate ions in the composition is 0 ppm to 100 ppm based on the total content of the composition.

2. 2. The siloxane resin composition according to claim 1, wherein the content of each of fluoride ions, chloride ions, nitrate ions, sulfate ions, and phosphate ions in the composition is 0 ppm to 10 ppm based on the total composition.

3. 3. The siloxane resin composition according to claim 1, wherein the content of any one of trifluoroacetate ions, methanesulfonate ions, trifluoromethanesulfonate ions, benzenesulfonate ions, and p-toluenesulfonate ions in the composition is 100 to 10,000 ppm based on the total content of the composition.

4. 3. The siloxane resin composition according to claim 1, wherein the average particle size of the silica particles (B) is 1 to 80 nm.

5. 3. The siloxane resin composition according to claim 1, wherein the mass average molecular weight of the siloxane resin (A) is 1,000 or more and 15,000 or less.

6. 3. The siloxane resin composition according to claim 1, wherein the siloxane resin (A) has phenyl groups, and the content of phenyl groups in the siloxane resin is 20 to 60 mol % relative to Si atoms.

7. 3. The siloxane resin composition according to claim 1, wherein the siloxane resin (A) has a radical polymerizable group and further contains a photopolymerization initiator.

8. 3. A cured film formed from the siloxane resin composition according to claim 1, wherein the cured film has an average light transmittance of 93% or more at a wavelength of 400 nm when the film thickness is 2 μm.

9. The cured film according to claim 8, which has a haze value per 1 μm of film thickness of less than 1.2%.

10. The cured film according to claim 8, having a surface roughness of less than 7.5 nm.

11. A cured film substrate comprising the cured film according to claim 8 formed on a substrate.

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