Resin composition, transparent resin composition film, and cover glass

Abstract

The present invention addresses the problem of providing a resin composition suitable for application to a surface of a curved glass base material while exhibiting high glass surface strength and transparency when cured.　The present invention is a resin composition containing a siloxane resin, colloidal silica, and a thixotropy-imparting agent, wherein the average secondary particle diameter of the colloidal silica is 10-100 nm, the average secondary particle diameter of the thixotropy-imparting agent is 50-500 nm, and the ratio of the average secondary particle diameter of the colloidal silica to the average secondary particle diameter of the thixotropy-imparting agent is 0.02 or more and less than 0.67 or is more than 1.5 and 2.0 or less.

Description

Resin composition, transparent resin composition film, and cover glass

[0001] This invention relates to a resin composition, a transparent resin composition film, and a cover glass.

[0002] Patent Document 1 describes a negative-type photosensitive resin composition containing a siloxane resin having a radical polymerizable group and a carboxyl group and / or a dicarboxylic acid anhydride group, a reactive monomer, a photoradical polymerization initiator, silica particles, and a siloxane compound having an oxetanyl group. It is stated that this composition provides high strength to the glass surface, thereby enabling the production of a cured film with excellent adhesion to inorganic and organic films.

[0003] Patent No. 6455636

[0004] However, the negative-type photosensitive resin composition described in Patent Document 1 had a problem in that, when applied to the surface of a curved glass substrate, the thickness of the transparent resin composition film made of the resin composition became uneven, making it difficult to obtain the high glass surface strength and transparency that should be obtained.

[0005] Therefore, the present invention aims to overcome the problems of the conventional technology and provide a resin composition that exhibits high glass surface strength and transparency when cured, while being suitable for application to the surface of a curved glass substrate.

[0006] The present inventors noticed that the negative-type photosensitive resin composition described in Patent Document 1 has low thixotropy and a relatively low viscosity, which causes dripping on the curved surface when applied to the surface of a curved glass substrate, and thus conceived the present invention. The present invention and its preferred embodiments for solving the above problem have the following configuration.

[0007] [1] A resin composition comprising a siloxane resin, colloidal silica, and a thixotropic agent, wherein the average secondary particle diameter of the colloidal silica is 10 to 100 nm, the average secondary particle diameter of the thixotropic agent is 50 to 500 nm, and the ratio of the average secondary particle diameter of the colloidal silica to the average secondary particle diameter of the thixotropic agent is 0.02 or more and less than 0.67 or greater than 1.5 and less than or equal to 2.0.

[0008] [2] The thixo ratio V ５ obtained by dividing the viscosity V measured at 25°C under a condition of 5 rpm using a rotational viscometer ５０ by the viscosity V measured at 25°C under a condition of 50 rpm using a rotational viscometer ５ / V ５０ is 1.25 or more and 4.00 or less. The resin composition according to [1].

[0009] [3] The resin composition according to [1] or [2], which is for inkjet coating.

[0010] [4] The resin composition according to any one of [1] to [3], wherein both the colloidal silica and the thixotropy imparting agent are amorphous.

[0011] [5] The resin composition according to any one of [1] to [4], wherein the thixotropy imparting agent is cellulose nanofiber or fumed silica.

[0012] [6] The resin composition according to [5], which contains 5 to 35 parts by mass of the thixotropy imparting agent relative to 100 parts by mass of the siloxane resin.

[0013] [7] The resin composition according to any one of [1] to [6], which contains 10 to 100 parts by mass of the colloidal silica relative to 100 parts by mass of the siloxane resin.

[0014] [8] The resin composition according to any one of [1] to [7], wherein the thixotropy imparting agent is the fumed silica having a hydrophobic surface.

[0015] [9] The resin composition according to any one of [1] to [8], further comprising high-refractive particles.

[0016]

[10] The resin composition according to [9], wherein the high-refractive particles are one or more selected from the group consisting of zirconium oxide, titanium oxide, and barium titanate.

[0017]

[11] The resin composition according to [9] or

[10] , wherein the average secondary particle diameter of the high-refractive particles is 10 to 100 nm.

[0018]

[12] The resin composition according to any one of [9] to

[11] , comprising 15 to 100 parts by mass of the high refractive particles with respect to 100 parts by mass of the siloxane resin.

[0019]

[13] A transparent resin composition film formed on a curved glass surface, comprising a siloxane resin, colloidal silica, and a thixotropic agent.

[0020]

[14] The transparent resin composition film according to

[13] , wherein the curved glass is a curved glass having a raised portion formed on its outer edge, and the product of the inclination angle θ (degrees) of the raised portion and the height h (mm) of the raised portion is 0.03 to 30.

[0021]

[15] A transparent resin composition film comprising a cured product of any of the resin compositions described in [1] to

[12] .

[0022]

[16] A cover glass having a transparent resin composition film according to any one of

[13] to

[15] .

[0023] The resin composition of the present invention exhibits high glass surface strength and transparency upon curing, while its thixotropy ratio can be adjusted to a range suitable for application to curved glass substrate surfaces. As a result, it hardly drips even on curved surfaces where application is difficult, and can be applied more uniformly across the entire surface of curved glass substrates than conventional methods.

[0024] In this invention, glass surface strength refers to the strength against stress applied to the glass when an external stress is applied to the glass.

[0025] This is an example of a cross-sectional view of a curved glass surface on which a transparent resin composition film of the present invention is formed. This is another example of a cross-sectional view of a curved glass surface on which a transparent resin composition film of the present invention is formed.

[0026] The following describes in detail embodiments of the resin composition, transparent resin composition film, and curved glass according to the present invention.

[0027] In this invention, "greater than or equal to" means the same as or greater than the numerical value shown. Similarly, "less than or equal to" means the same as or less than the numerical value shown.

[0028] The resin composition of the present invention contains a siloxane resin, colloidal silica, and a thixotropic agent.

[0029] [Siloxane Resin] The siloxane resin is preferably a polymer having a siloxane skeleton as a repeating unit, having a radical polymerizable group and a carboxyl group and / or a dicarboxylic acid anhydride group. It is more preferably a hydrolysis condensate of an organosilane compound having a radical polymerizable group and an organosilane compound having a carboxyl group and / or a dicarboxylic acid anhydride group, and even more preferably a hydrolysis condensate of an organosilane compound having a methyl group and an organosilane compound having a phenyl group. The siloxane resin has excellent transparency. Examples of the radical polymerizable group include a vinyl group, an α-methylvinyl group, an allyl group, a styryl group, and a (meth)acryloyl group. Of these, the (meth)acryloyl group is preferred from the viewpoint of improving the surface strength of the transparent resin composition film.

[0030] Examples of organosilane compounds having the radical polymerizable group include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(methoxyethoxy)silane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinylmethyldi(methoxyethoxy)silane, allyltrimethoxysilane, allyltriethoxysilane, allyltri(methoxyethoxy)silane, allylmethyldimethoxysilane, allylmethyldiethoxysilane, allylmethyldi(methoxyethoxy)silane, styryltrimethoxysilane, styryltriethoxysilane, styryltri(methoxyethoxy)silane, styrylmethyldimethoxysilane, styrylmethyldiethoxysilane, styrylmethyldi(methoxyethoxy)silane, γ-acryloylpropyltrimethoxysilane, γ-acryloylpropyltriethoxysilane, γ-methacryloylpropyltrimethoxysilane, and γ-methacryloylpropyltriethoxysilane. Of these, one or more of γ-acryloylpropyltrimethoxysilane, γ-acryloylpropyltriethoxysilane, γ-methacryloylpropyltrimethoxysilane, and γ-methacryloylpropyltriethoxysilane are preferred from the viewpoint of improving the surface strength of the transparent resin composition film.

[0031] Examples of the organosilane compounds having a carboxyl group include urea group-containing organosilane compounds and urethane group-containing organosilane compounds. Two or more of these may be used. More specifically, examples include 3-trimethoxysilylpropionic acid, 3-triethoxysilylpropionic acid, 3-dimethylmethoxysilylpropionic acid, 3-dimethylethoxysilylpropionic acid, 4-trimethoxysilylbutyrate, 4-triethoxysilylbutyrate, 4-dimethylmethoxysilylbutyrate, 4-dimethylethoxysilylbutyrate, 5-trimethoxysilylvaleric acid, and 5-triethoxysilylvaleric acid.

[0032] Examples of organosilane compounds having the dicarboxylic acid anhydride group include 3-trimethoxysilylpropyl succinic anhydride, 3-triethoxysilylpropyl succinic anhydride, 3-dimethylmethoxysilylpropyl succinic anhydride, 3-dimethylethoxysilylpropyl succinic anhydride, 3-trimethoxysilylpropylcyclohexyldicarboxylic acid anhydride, 3-triethoxysilylpropylcyclohexyldicarboxylic acid anhydride, 3-dimethylmethoxysilylpropylcyclohexyldicarboxylic acid anhydride, 3-dimethylethoxysilylpropylcyclohexyldicarboxylic acid anhydride, 3-trimethoxysilylpropylphthalic acid anhydride, 3-triethoxysilylpropylphthalic acid anhydride, 3-dimethylmethoxysilylpropylphthalic acid, and 3-dimethylethoxysilylpropylphthalic acid.

[0033] Examples of organosilane compounds containing the methyl group include methyltrimethoxysilane, methyltriethoxysilane, methyltri(methoxyethoxy)silane, methyltripropoxysilane, methyltriisopropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, cyclohexylmethyldimethoxysilane, octadecylmethyldimethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinylmethyldi(methoxyethoxy)silane, allylmethyldimethoxysilane, allylmethyldiethoxysilane, allylmethyldi(methoxyethoxy)silane, styrylmethyldimethoxysilane, styrylmethyldiethoxysilane, and styrylmethyldi(methoxyethoxy)silane. Of these, from the viewpoint of increasing the crosslinking density of the transparent resin composition film and further improving the glass surface strength of the transparent member, one or more of the trifunctional methyltrimethoxysilane, methyltriethoxysilane, methyltri(methoxyethoxy)silane, methyltripropoxysilane, methyltriisopropoxysilane, and methyltributoxysilane are preferred.

[0034] Examples of organosilane compounds containing the phenyl group include phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane. Of these, trifunctional phenyltrimethoxysilane and / or trifunctional phenyltriethoxysilane are preferred from the viewpoint of increasing the crosslinking density of the resin composition and further improving the glass surface strength of the transparent resin composition film.

[0035] Other organosilane compounds include, for example, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, tridecafluorooctyltrimethoxysilane, and tridecafluorooctyltriethoxysilane.

[0036] Furthermore, in the siloxane resin, it is preferable that the total silane component contains 10 to 60 mol% of methyl group-containing silane compounds, 10 to 50 mol% of phenyl group-containing silane compounds, 5 to 40 mol% of carboxyl group- or dicarboxylic acid anhydride group-containing silane compounds, and 20 to 70 mol% of radical polymerizable group-containing silane compounds, with a more preferable content of 20 to 50 mol% of methyl group-containing silane compounds, 15 to 40 mol% of phenyl group-containing silane compounds, 10 to 30 mol% of carboxyl group- or dicarboxylic acid anhydride group-containing silane compounds, and 30 to 60 mol% of radical polymerizable group-containing silane compounds.

[0037] The weight-average molecular weight (hereinafter referred to as Mw) of the siloxane resin is preferably 1,000 or more, and more preferably 1,500 or more, from the viewpoint of improving glass surface strength. On the other hand, the Mw of the siloxane resin is preferably 10,000 or less, and more preferably 6,000 or less, from the viewpoint of improving coating characteristics. Here, the Mw of the siloxane resin refers to the value obtained by measuring with gel permeation chromatography (GPC) using tetrahydrofuran as a carrier and converting it using a calibration curve with standard polystyrene.

[0038] The resin composition may contain resins other than the siloxane resin. Examples of such resins include acrylic resins, cardo resins, novolac resins, polyimide resins, polyimide precursors, polybenzoxazole resins, polybenzoxazole precursors, and polyamide resins. Among these, acrylic resins and cardo resins with an Mw of 5,000 to 150,000 are preferred from the viewpoint of transparency.

[0039] The content of the siloxane resin in the solid content of the resin composition is preferably 10% by mass or more and 70% by mass or less, more preferably 20% by mass or more and 50% by mass or less, and even more preferably 25% by mass or more and 45% by mass or less. The content of resins other than the siloxane resin is preferably 5 parts by mass or more and 50 parts by mass or less, and more preferably 10 parts by mass or more and 30 parts by mass or less, per 100 parts by mass of the siloxane resin.

[0040] [Colloidal Silica] The colloidal silica is preferably a colloidal sol obtained by dispersing fine particle powder of porous amorphous silica (silicon dioxide) in a solvent medium. Generally, it has a large internal surface area and a large specific surface area, and therefore has strong adsorption capacity. It is mainly produced by a wet process in which sodium silicate is reacted with an acid such as sulfuric acid. The colloidal silica can reduce the thermal expansion coefficient of the transparent resin composition film obtained by curing the resin composition of the present invention, or the transparent resin composition film of the present invention, thereby reducing film stress. Furthermore, it can impart high surface hardness and scratch resistance.

[0041] The colloidal silica can be of various types and is not particularly limited, but colloidal silica with an average secondary particle diameter of 10 to 100 nm is preferred, more preferably 15 to 80 nm, and even more preferably 20 to 50 nm. By having an average secondary particle diameter of 10 to 100 nm for the colloidal silica, the resin composition can be given excellent coating properties, excessive aggregation can be suppressed, and a decrease in transparency due to clouding can be suppressed.

[0042] In this invention, the average secondary particle diameter refers to the average secondary particle diameter measured by dynamic light scattering (DLS) (the average particle diameter measured from fluctuations in scattered light caused by particles undergoing Brownian motion in a solvent). An example of a particle diameter distribution measuring instrument is the nanoPartica® SZ-100S2 manufactured by Horiba, Ltd. The specific measurement method is as described in the examples.

[0043] Furthermore, preferred colloidal silica types include those in which spherical silica particles with an average secondary particle diameter of 10 to 100 nm are dispersed in a solvent medium, those in which silica particles aggregated in chains of about 5 to 50 nm in thickness and 40 to 400 nm in length are dispersed in a solvent medium, those in a pearl necklace type in which spherical silica particles with an average secondary particle diameter of 10 to 100 nm and spherical silica particles linked together in a pearl necklace-like manner with a length of 50 to 400 nm are dispersed in a solvent medium, and those in a ring type in which silica particles with an average secondary particle diameter of 10 to 100 nm are aggregated in a ring shape and dispersed in a solvent medium. Among these, spherical silica particles are preferred as the colloidal silica from the viewpoint of suppressing shrinkage of the transparent resin composition film and providing scratch resistance. Examples of the colloidal silica include IPA-ST, IPA-ST-L, IPA-ST-ZL, PMA-ST, MEK-ST, Snowtex®-20, Snowtex®-O, Snowtex®-C, and Snowtex®-S manufactured by Nissan Chemical Corporation, and Adelite® AT-20, AT-20N, AT-20A, and AT-300 manufactured by ADEKA Corporation.

[0044] Examples of the chain-type colloidal silica in which the chain-like aggregated silica particles are dispersed in a solvent medium include Snowtex®-UP and Snowtex®-OUP manufactured by Nissan Chemical Corporation. Examples of the pearl-necklace-type colloidal silica in which the spherical silica particles linked together in a pearl-necklace-like manner are dispersed in a solvent medium include Snowtex®-PS-S, Snowtex®-PS-M, Snowtex®-PS-SO and Snowtex®-PS-MO manufactured by Nissan Chemical Corporation.

[0045] The colloidal silica content is preferably 10 parts by mass or more and 100 parts by mass or less, and more preferably 35 parts by mass or more and 100 parts by mass or less, per 100 parts by mass of the siloxane resin. When the colloidal silica content is 10 parts by mass or more, the surface hardness of the transparent resin composition film is improved, and when it is 100 parts by mass or less, the transparency of the transparent resin composition film is maintained at a high level.

[0046] [Thixotropic agent] The thixotropic agent can be used to impart both thixotropy and pseudoplasticity to the resin composition, thereby adjusting the thixotropy ratio of the resin composition.

[0047] Specific examples of the thixotropic agent include inorganic thixotropic agents such as fumed silica and calcium carbonate, and organic thixotropic agents such as cellulose nanofibers, polyether esters, polyesters, polyamides, polycarboxylic acid amides, modified urea, and oxidized polyethylene. Among these, cellulose nanofibers or fumed silica are preferred as the thixotropic agent from the viewpoint of ease of controlling fluidity and adjusting viscosity. Furthermore, fumed silica is more preferred because it is a high-purity, non-porous particle in which primary particles aggregate to have a large specific surface area and many silanol groups on the surface, and thixotropy can be imparted even with a small amount of addition due to the action of hydrogen bonding of the silanol groups on the surface.

[0048] The fumed silica is generally produced by a dry method in which a halogenated silane, such as silicon tetrachloride, is hydrolyzed in an oxyhydrogen flame. The fumed silica preferably has a hydrophobic surface. Having a hydrophobic surface improves the transmittance of the transparent resin composition film with the appropriate selection of dispersants, making it easier to obtain a transparent resin composition film with superior transparency.

[0049] One method for giving the fumed silica a hydrophobic surface, that is, for subjecting it to a hydrophobic surface treatment, is to chemically treat hydrophilic fumed silica with a reactive silane such as chlorosilane, hexamethyldisilazane, and polydimethylsiloxane. Specific examples of fumed silica subjected to this hydrophobic surface treatment include commercially available products such as AEROSIL® R974 (dimethyldichlorosilane treatment) and AEROSIL® RX200 (hexamethyldisilazane treatment) from Nippon Aerosil Co., Ltd., and FS2110 (polydimethylsiloxane treatment), FS5115 and FS5170 (dimethyldichlorosilane treatment), FS9120 and FS9150 (hexamethyldisilazane treatment) from SISIB.

[0050] Another method for applying a hydrophobic surface treatment involves contacting the fumed silica, manufactured by a dry process, with a gaseous hydrophobic agent. In particular, it is preferable to contact the fumed silica with the gaseous hydrophobic agent while weakly stirring it with a stirring blade or the like, or while flowing the fumed silica with the gaseous hydrophobic agent or an inert gas such as nitrogen.

[0051] As the hydrophobic agent, a low molecular weight cyclic dimethylsiloxane with a boiling point of 300°C or less that is easily gasified is preferred, such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane. Among these, octamethylcyclotetrasiloxane, which is easily purified by distillation, is more preferred.

[0052] The amount of the hydrophobic agent used for surface treatment is preferably such that the M value, an indicator of lipophilicity as described in Japanese Patent No. 4799830, is between 48 and 65. Specifically, although it varies depending on the type of hydrophobic agent used, it is preferably between 10 parts by mass and 100 parts by mass per 100 parts by mass of fumed silica.

[0053] Examples of commercially available calcium carbonate products include colloidal calcium carbonate "NEOLIGHT® series" (Takehara Chemical Industry Co., Ltd.) and synthetic calcium carbonate "Viscoexcel® 30" (Shiraishi Calcium Co., Ltd.).

[0054] The aforementioned cellulose nanofibers are materials that have been finely broken down and refined to the nanoscale, and possess excellent characteristics such as being lightweight, high strength, high dimensional stability, high transparency, high water retention, and the effect of increasing viscosity. Examples of commercially available products include Rheocrysta® I-2AX (Daiichi Kogyo Seiyaku).

[0055] The aforementioned polyether ester is a compound having an ether group and an ester group in its molecule, and commercially available examples include Disparon® 3900N (Kusumoto Chemical Co., Ltd.).

[0056] The polyester is a compound having an ester group in its molecule, and commercially available examples include RCM-100 (Kyoeisha Chemical Co., Ltd.).

[0057] The aforementioned polyamide is a compound having a -CONH- structure within its molecule, and can be obtained by reacting a carboxylic acid compound with an amine compound. Examples of commercially available products include Disparon® 3900EF (manufactured by Kusumoto Chemical Co., Ltd.).

[0058] The aforementioned polycarboxylic acid amide is a compound having a carboxylic acid (or carboxylic acid salt) and a -CONH- structure within its molecule. Examples of commercially available products include BYK®-405 (manufactured by BYK).

[0059] The aforementioned modified urea is a compound obtained by reacting an isocyanate compound with an amine compound, and commercially available examples include BYK®-410, BYK®-411, and BYK®-415 (all manufactured by BYK).

[0060] Said oxidized polyethylene is an oxide of polyethylene, and examples of commercially available products include DISPARLON (registered trademark) 4200-20, DISPARLON (registered trademark) 4200-10, DISPARLON (registered trademark) PF-911, DISPARLON (registered trademark) PF-930, DISPARLON (registered trademark) 4401-25X, DISPARLON (registered trademark) 4401-25M, DISPARLON (registered trademark) NS-30 (all manufactured by Kusumoto Chemicals, Ltd.), etc.

[0061] It should be noted that, similar to colloidal silica, an amorphous thixotropic agent is preferred. If the thixotropic agent is crystalline, it is difficult to mix uniformly, and phase separation is likely to occur. In addition, the crystalline particles of the thixotropic agent act as nuclei, which promotes the recrystallization of colloidal silica, causing aggregation and caking, which may impair the long-term stability of said resin composition.

[0062] The average particle diameter of the primary particles of said fumed silica is preferably 10 nm or more and 40 nm or less. By setting the average particle diameter of the primary particles of said fumed silica to 10 nm or more and 40 nm or less, it becomes easy to adjust the secondary particle diameter to the range of 50 to 500 nm, whereby excellent coating properties can be imparted to said resin composition, excessive aggregation is suppressed, and the viscosity of said resin composition can be stabilized.

[0063] The average secondary particle diameter of said thixotropic agent is preferably 50 to 500 nm. When the average secondary particle diameter of said thixotropic agent is 50 to 500 nm, more preferably 100 to 400 nm, and still more preferably 150 to 300 nm, excellent coating properties can be imparted to said resin composition, excessive aggregation is suppressed, and the viscosity of said resin composition can be stabilized.

[0064] Further, the average secondary particle diameter d of said colloidal silica Ｓ to the average secondary particle diameter d of said thixotropic agent Ｔ the ratio d Ｓ / d Ｔ is 0.02 or more and less than 0.67, or more than 1.5 and 2.0 or less. In other words, the ratio of the average secondary particle diameter of said colloidal silica to the average secondary particle diameter of said thixotropic agent d Ｓ :dＴ 2:1 to 1:50 (however, d Ｓ :d Ｔ (Excluding the range of 1.5:1 to 1:1.5). d Ｓ / d Ｔ By setting the value to 0.02 or more and less than 0.67 or greater than 1.5 and less than or equal to 2.0, the colloidal silica and the thixotropic agent form a heterogeneous three-dimensional structure, allowing thixotropy to be imparted even with a small amount of addition. Note that the colloidal silica and the thixotropic agent should be of similar size, specifically, d Ｓ / d Ｔ is 0.67 or more and 1.5 or less, i.e., d Ｓ :d Ｔ However, in the range of 1.5:1 to 1:1.5, the colloidal silica and the thixotropic agent are mixed uniformly, resulting in a reduced effect of imparting thixotropy, so this range is excluded.

[0065] Furthermore, because the average secondary particle size of the thixotropic agent is larger than that of the colloidal silica, it is possible to impart thixotropy with a small amount of additive while suppressing excessive aggregation and obtaining a resin composition with excellent transparency. That is, d Ｓ / d Ｔ Preferably, it is 0.02 or more and less than 0.67, and more preferably 0.03 or more and 0.5 or less (d Ｓ :d Ｔ (d) is 1:2 to 1:30, more preferably 0.05 or more and 0.3 or less. Ｓ :d Ｔ The ratio is 1:3 to 1:20.

[0066] The content of the thixotropic agent is preferably 5 parts by mass or more and 35 parts by mass or less per 100 parts by mass of the siloxane resin. If the content is 5 parts by mass or more and 35 parts by mass or less, it becomes easier to adjust the thixotropic ratio within the range of the present invention. If the content is 10 parts by mass or more and 25 parts by mass or less, it is even more preferable because it becomes even easier to adjust most of the thixotropic agent described above within the range of the thixotropic ratio of the present invention.

[0067] The total content of the cellulose nanofibers and / or the fumed silica is preferably 5 parts by mass or more and 35 parts by mass or less, and more preferably 10 parts by mass or more and 25 parts by mass or less, per 100 parts by mass of the siloxane resin, for the same reasons as the content of the thixotropic agent.

[0068] [High-refractive index particles] The resin composition may contain high-refractive index particles to adjust the refractive index of the layer composed of the resin composition. For example, when a film of the resin composition is formed on a glass substrate, if the refractive index of the film is lower than that of the glass substrate, ambient light may be diffusely reflected at the interface between the film and the glass substrate, which may reduce the optical performance of the glass substrate, such as a decrease in visibility due to reflection of diffusely reflected light.

[0069] In such cases, by incorporating highly refractive particles into the resin composition, the refractive index of the film can be increased, and by reducing the difference in refractive index between the glass substrate and the film as much as possible, diffuse reflection at the interface between the glass substrate and the film can be reduced.

[0070] High-refractive-index particles are defined as particles with a refractive index (633 nm) of 1.80 or higher. Examples of high-refractive-index particles include inorganic particles such as zirconium oxide, titanium oxide, zinc oxide, barium titanate, niobium oxide, hafnium oxide, lanthanum oxide, cerium oxide, titanium silicide, and cadmium sulfide, as well as organic particles such as cyanuryl chloride, anilines, and diamines, and composite particles of inorganic particle dispersions and organic-inorganic hybrid systems in which the inorganic particles are dispersed in an organic resin. Among these, one or more selected from zirconium oxide, titanium oxide, and barium titanate are preferred from the viewpoint of high transparency and ease of availability.

[0071] The average secondary particle diameter of the high refractive index particles is preferably 10 to 100 nm, and more preferably 20 to 50 nm. A minimum average secondary particle diameter of 100 nm, more preferably 50 nm, allows for high transparency, while a minimum average secondary particle diameter of 10 nm, more preferably 20 nm, suppresses aggregation and maintains stable dispersibility.

[0072] The content of the high-refractive index particles is preferably 15 to 100 parts by mass, more preferably 20 to 80 parts by mass, and even more preferably 25 to 50 parts by mass per 100 parts by mass of the siloxane resin. Including 15 parts by mass or more per 100 parts by mass of the siloxane resin makes it possible to increase the refractive index of the resin composition, while including 100 parts by mass or less makes it possible to avoid problems such as cohesive failure when a film is formed. Furthermore, in order to disperse the high-refractive index particles more stably and uniformly, it is more preferable that the content of the high-refractive index particles be 80 parts by mass or less per 100 parts by mass of the siloxane resin.

[0073] [Diluent] The resin composition may also preferably contain a diluent to adjust its viscosity to a lower level. Examples of the diluent include organic solvents, reactive diluents, and water.

[0074] However, the reactive diluent may be irradiated with energy rays such as ultraviolet light after application to make it tack-free. Also, if the diluent is water, it evaporates slowly, making it difficult to adjust the thixotropy ratio to the range of the present invention. For these reasons, the diluent is preferably the organic solvent.

[0075] Examples of the aforementioned organic solvents include ethers, acetates, esters, ketones, aromatic hydrocarbons, amides, and alcohols. Examples of the aforementioned ethers include alkylene glycol ethers such as ethylene glycol monoethyl ether and propylene glycol monomethyl ether, dialkylene glycol ethers such as diethylene glycol monomethyl ether and dipropylene glycol monomethyl ether, trialkylene glycol ethers such as tripropylene glycol monomethyl ether and tripropylene glycol monoethyl ether, and tetrahydrofuran.

[0076] Examples of the acetates mentioned above include butyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, cyclohexanol acetate, propylene glycol diacetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and dipropylene glycol methyl ether acetate.

[0077] Examples of the aforementioned esters include alkyl lactate esters; ethyl hydroxymethylpropionate, methyl methoxypropionate, ethyl methoxypropionate, methyl ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl hydroxymethylbutanoate, methoxybutyl acetate, methyl methoxybutyl acetate, methyl methoxybutyl propionate, ethyl acetate, propyl acetate, butyl acetate, pentyl formate, pentyl acetate, butyl propionate, ethyl butyrate, propyl butyrate, butyl butyrate, methyl pyruvate, ethyl pyruvate, methyl acetoacetate, ethyl acetoacetate, etc.

[0078] Examples of the ketones include methyl ethyl ketone, cyclohexanone, 2-heptanone, and 3-heptanone. Examples of the aromatic hydrocarbons include toluene and xylene. Examples of the amides include N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide. Examples of the alcohols include butyl alcohol, isobutyl alcohol, pentanol, 4-methyl-2-pentanol, 3-methyl-2-butanol, 3-methyl-3-methoxybutanol, and diacetone alcohol.

[0079] The aforementioned organic solvent may be used in combination of two or more types.

[0080] Among these, organic solvents such as ethers, acetates, and alcohols with a vapor pressure of 1 Pa or more and 1000 Pa or less at 20°C are preferred. This is because using these organic solvents suppresses the drying rate, making it easier to uniformly disperse the colloidal silica and the thixotropic agent, and thus stabilizing the thixotropic ratio.

[0081] Examples of the reactive diluents include various monoepoxy compounds and glycidyl ether compounds of polyhydric alcohols.

[0082] From the viewpoint of optimizing the surface smoothness of the transparent resin composition film after coating, the content of the diluent is preferably 20% by mass or more, and more preferably 30% by mass or more, based on 100% by mass of the resin composition. On the other hand, from the viewpoint of maintaining the performance of the colloidal silica and the thixotropizing agent, it is preferably 80% by mass or less, and more preferably 70% by mass or less, based on 100% by mass of the resin composition.

[0083] [Other components] The resin composition may contain crosslinking agents, surfactants, adhesion improvers, etc.

[0084] Examples of the crosslinking material include oxetane resin, silane coupling agent, blocked isocyanate, photopolymerization initiator, and thiol compound.

[0085] The oxetane resin is an analog of epoxy resin, and by using an onium salt or the like as a catalyst and a carboxylic acid, thiol, etc. having two or more functional groups in one molecule, a ring-opening reaction and a cross-linking reaction can occur to form a network polymer. It has features such as rapid curing, suppression of curing shrinkage, and excellent adhesion to plastic materials. A commercially available example is the "Aron Oxetane (registered trademark) OXT" series from Toagosei Co., Ltd. The content of the oxetane resin is preferably 1 part by mass or more and 30 parts by mass or less per 100 parts by mass of the siloxane resin.

[0086] The silane coupling agent is a compound that possesses functional groups that bind to both organic and inorganic materials within its molecule, and can be used to improve mechanical strength, improve adhesion, and modify surfaces. Examples of functional groups that bind to organic materials include vinyl groups, epoxy groups, styryl groups, methacrylic groups, mercapto groups, and amino groups, while examples of functional groups that bind to inorganic materials such as coverslips include methoxy groups and ethoxy groups. The content of the silane coupling agent is preferably 0.3 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the siloxane resin.

[0087] Examples of the silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, and N-(2-aminoethyl)-3-amino Examples include propyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, 3-mercaptopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-isocyanatetopropyltriethoxysilane, and p-styryltrimethoxysilane.

[0088] The blocked isocyanate is a compound having isocyanate groups blocked by a blocking agent. In the resin composition, the blocked isocyanate can be used as a curing agent for the siloxane resin. The blocked isocyanate regenerates its isocyanate groups by dissociating (deprotecting) the blocking agent when heated at a relatively low temperature. The regenerated isocyanate groups react with the active groups in the siloxane resin, causing the siloxane resin to harden and become tougher. Because the isocyanate groups are regenerated, the blocked isocyanate has a long pot life, and the resin composition containing the blocked isocyanate has excellent viscosity stability.

[0089] The type of blocked isocyanate is not particularly limited, and commercially available ones can be used. The content of the blocked isocyanate is preferably 1 part by mass or more and 80 parts by mass or less per 100 parts by mass of the siloxane resin.

[0090] Examples of the photopolymerization initiators include oxime ester photopolymerization initiators, carbazole-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and α-aminoalkylphenone-based photopolymerization initiators. Examples of commercially available photopolymerization initiators include ADEKA ARCULUS® N-1919T, NCI-831E, NCI-930, NCI-730 (all manufactured by ADEKA Corporation), Irgacure® OXE01, OXE02, Omnirad® 819, Omnirad® TPO-L, and Omnirad® 127 (all manufactured by BASF Japan Ltd.). Two or more of these may be included. The content of the photopolymerization initiator is preferably 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the siloxane resin.

[0091] The thiol compound can improve the solvent resistance and adhesion of the transparent resin composition film even at low bake temperatures. Furthermore, by inducing the reactivity of the siloxane resin and strengthening the transparent resin composition film itself, the toughness of the surface of the transparent resin composition film can be more effectively improved. Specific examples of the thiol compound include polyfunctional thiol compounds. The thiol compound can be used individually or in combination of two or more types. Preferably, the content of the thiol compound is 0.1% by mass or more and 5.0% by mass or less based on the total solid content of the resin composition.

[0092] The surfactant is included primarily for the purpose of improving wettability with the substrate and improving the uniformity of the coating film thickness. From an environmental standpoint, the surfactant is preferably PFAS-free, and examples include anionic surfactants such as ammonium lauryl sulfate and polyoxyethylene alkyl ether sulfate triethanolamine, cationic surfactants such as stearylamine acetate and lauryltrimethylammonium chloride, amphoteric surfactants such as lauryldimethylamine oxide, nonionic surfactants such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether and sorbitan monostearate, and silicone-based surfactants. Two or more of these may be included. The surfactant content is preferably 0.001 parts by mass or more and 1 part by mass or less per 100 parts by mass of the siloxane resin.

[0093] The adhesion-improving agent is included primarily for the purpose of improving adhesion to the substrate. Examples of the adhesion-improving agent include titanium chelating agents, aluminum chelating agents, zirconium chelating agents, and compounds obtained by reacting aromatic amine compounds with alkoxy group-containing silicon compounds. Two or more of these may be included. By including the adhesion-improving agent, the adhesion to the glass substrate or a material provided on its surface can be enhanced. The content of the adhesion-improving agent is preferably 0.1 parts by mass or more and 30 parts by mass or less per 100 parts by mass of the siloxane resin.

[0094] [Properties of the Resin Composition] The viscosity of the resin composition is measured using a rotational viscometer under the conditions of 25°C and 50 rpm. ５０ It is preferable that the viscosity V is 5 mPa·s or more and 20 mPa·s or less. ５０ By setting the pressure between 5 mPa·s and 20 mPa·s, it becomes easier to apply the coating to the curved surface of a curved glass substrate using methods such as inkjet printing.

[0095] The viscosity of the resin composition is measured using a rotational viscometer at 25°C and 5 rpm. ５ The viscosity V is measured using a rotational viscometer at 25°C and 50 rpm. ５０ The thixotropic ratio V is calculated by dividing by [the specified factor]. ５ / V ５０ It is preferable that the value is between 1.25 and 4.00.

[0096] If the thixotropy ratio is within the range of 1.25 to 4.00, the thixotropy is appropriately expressed and maintained, and even when applied to the surface of a curved glass substrate, there is almost no dripping on the curved surface, and the resin composition can be applied to the entire surface of the curved glass with good productivity.

[0097] If the thixotropy ratio is less than 1.25, the gelation of the resin composition applied to the curved glass substrate will not proceed, making it easy for the resin composition to drip from the edges of the curved portion to other sides of the curved glass substrate. Furthermore, the film thickness at the edges of the curved portion may become thinner, potentially reducing the glass surface strength of the transparent member. On the other hand, if the thixotropy ratio is higher than 4.00, the transparent resin composition film formed after application may gel before leveling occurs, resulting in increased surface irregularities, which may reduce the glass surface strength of the transparent member or worsen its transparency.

[0098] Generally, thixotropy refers to the property of viscosity changing depending on the time shear stress is applied (the longer the shear stress is applied, the lower the viscosity). In this invention, we focused on one aspect of this thixotropy: the phenomenon in which the viscosity of the resin composition decreases due to shear stress such as vibration during stirring or pressure, and then increases after standing. If the resin composition has an appropriate thixotropy ratio, which is one aspect of pseudoplasticity, it can be made into a liquid viscosity suitable for application by placing the resin composition in the container of the coating apparatus and stirring, while the viscosity increase after standing maintains the shape of the transparent resin composition film, so that it hardly drips when applied to the curved surface of the curved glass, and the glass surface strength and transparency of the transparent member can be improved.

[0099] Examples of the aforementioned rotary viscometers include the "RSX-CPS" manufactured by Eiko Seiki Co., Ltd., and the "RE-215 type viscometer" and "TV-100E" manufactured by Toki Sangyo Co., Ltd.

[0100] [Method for Preparing the Resin Composition] The method for preparing the resin composition of the present invention will be described below with reference to an example. However, the following description is illustrative for implementation purposes only, and the present invention shall not be construed as being limited to this preparation method.

[0101] A preferred method for preparing the resin composition of the present invention is to add the diluent to each of the colloidal silica and the thixotropic agent, disperse them using a disperser to prepare dispersions, and then add these dispersions, along with a solution of the siloxane resin and, if necessary, additional diluents and other components such as surfactants, and stir. Filtration may also be performed if necessary.

[0102] Examples of the aforementioned dispersers include ball mills, bead mills, sand grinders, three-roll mills, and high-speed impact mills. Among these, bead mills are preferred for their efficiency in dispersion and for fine dispersion. Examples of the aforementioned bead mills include ball mills, basket mills, pin mills, and dyno mills. Examples of beads used in the aforementioned bead mills include titania beads, zirconia beads, and zircon beads.

[0103] The diameter of the beads is preferably 0.03 mm or more and 1.0 mm or less. When the primary particle size of the colloidal silica or the thixotropic agent and the particle size of the secondary particles formed by the aggregation of the primary particles are small, it is preferable to use very small beads with a diameter of 0.03 mm or more and 0.10 mm or less. In this case, it is also preferable to use a bead mill equipped with a separator that uses a centrifugal separation method capable of separating the very small beads from the dispersion. On the other hand, when the colloidal silica or the thixotropic agent contains coarse particles of about submicron size, it is preferable to use beads with a diameter of 0.10 mm or more in order to obtain sufficient grinding power.

[0104] <Transparent Resin Composition Film and Transparent Member> The transparent resin composition film of the present invention is formed on a curved glass substrate and contains a siloxane resin, colloidal silica, and a thixotropic agent. The transparent member of the present invention comprises the curved glass substrate and the transparent resin composition film of the present invention formed on the curved glass substrate.

[0105] [Curved Glass Substrate] Examples of the glass material for the glass substrate include soda glass, alkali-free glass, and quartz glass. Other resin layers, inorganic films, pixels, wiring, etc., may be present on the surface of the glass substrate.

[0106] In this invention, "having a curved surface" means having a shape characteristic different from that of a flat plate. Hereinafter, the glass substrate having a curved surface will also be referred to as a "curved glass substrate."

[0107] The glass substrate preferably has a recess or protrusion with an inclination angle of 10° to 30°. For example, in Figure 1, the curved portion 10 of the glass substrate 5 is a recess having a rising portion with an inclination angle θ° from the corner portion 11 of the curved surface of the glass substrate, and the bottom portion 13 widens beyond where it reaches the bottom edge portion 20 through the side portion 12. Also, for example, in Figure 2, the portion surrounded by the curved portion 10 of the glass substrate 5 is a protrusion rising with an inclination angle θ° from the bottom edge portion 20 near the end of the glass substrate, and the flat portion 30 widens beyond where it reaches the corner portion 11 through the side portion 12.

[0108] In this invention, the inclination angle θ is the angle formed by a line passing through the flat portion 30 and a line passing through the side portion 12 within a cross-section including a curved surface as shown in Figures 1 and 2, with the line passing through the flat portion 30 as the starting point (0°). The height h of the rising portion refers to the height when a perpendicular line is drawn from the corner portion 11 to the extension line of the bottom portion 13. If the product of the inclination angle θ° and the height h (mm) of the rising portion is within the range of 0.03 to 30, the ratio of the film thickness of the transparent resin composition film described later t ２ / t １ It is possible to make it 3 or less.

[0109] [Transparent Resin Composition Film] The siloxane resin, colloidal silica, thixotropic agent, and other components of the transparent resin composition film can preferably be the same as those described above as components of the resin composition of the present invention. That is, the resin composition of the present invention is also the resin composition that forms the transparent resin composition film of the present invention. Furthermore, the transparent resin composition film of the present invention consists of a cured product of the resin composition of the present invention.

[0110] The resin composition of the present invention can be applied not only to the flat portion 30 of the glass substrate 5 in Figures 1 and 2, but also to all of the curved corners 11, side portions 12, bottom edges 20, and bottom 13 of the glass substrate 5.

[0111] The transparent resin composition film 1 has the thinnest film thickness near the corner 11 (this film thickness is t １ (Assuming this), the film thickness is thickest near the bottom edge 20 (this film thickness is t ２ (Assume) The ratio t of this film thickness ２ / t １ This depends on the inclination angle θ° and the properties of the resin composition of the present invention, t ２ / t １ The closer this value is to 1, the more uniform the thickness of the transparent resin composition film 1 is across the entire curved glass substrate 5.

[0112] In the present invention, if the product of the inclination angle θ° and the height h (mm) of the rising portion is within the range of 0.03 to 30, the ratio of the film thickness of the transparent resin composition film is t ２ / t １It becomes easier to make the thixotropic ratio V of the resin composition of the present invention. ５ / V ５０ This is derived from the fact that the product of the inclination angle θ° of the rising or falling portion and the height h (mm) of the rising portion is within the above range, indicating that it can be applied as a transparent coating material to any curved glass substrate.

[0113] Methods for processing the aforementioned glass material into a curved surface include, for example, cutting with a precision miniature drill, grinding using a polishing machine, and bending by applying heat to deform the shape. Examples of curved surfaces include concave shapes as shown in Figure 1 and convex shapes as shown in Figure 2.

[0114] [Method for forming a transparent resin composition film] Next, a method for forming a transparent resin composition film by applying the resin composition to a curved glass substrate will be described. This method consists of, for example, the steps of applying the resin composition to the surface of the curved glass substrate to form a coating film, drying the coating film, and / or curing the coating film. If the reactive diluent is used as the diluent, the step of irradiating the transparent resin composition film with energy rays is added.

[0115] Prior to coating, the glass substrate may be pre-treated, such as with UV treatment or plasma treatment, to improve the adhesion between the glass substrate and the transparent resin composition film.

[0116] In the process of forming the coating film, the resin composition is applied to the curved glass substrate by methods such as inkjet, spin coating, slit coating, dip coating, spray coating, or printing to form the coating film. Among these application methods, the inkjet method is preferred because it is easy to apply to the curved surface of the curved glass substrate and the amount of coating can be easily controlled. The application speed in the inkjet method is generally in the range of 10 mm / second to 400 mm / second.

[0117] Typical drying methods for the coating film include vacuum drying and heat drying. Both vacuum drying and heat drying may be performed, or only one of them may be performed. For heat drying, a hot plate, oven, or infrared heating may be used. The heating temperature varies depending on the type and purpose of the coating film, but it is preferable to heat it in the range of 50°C to 180°C for 1 minute to several hours. In the drying process, volatile components such as the diluent are removed.

[0118] The thickness of the coating film after drying depends on the solid content concentration and viscosity of the resin composition, but is preferably 0.1 μm to 10 μm, and more preferably 0.5 μm to 3 μm. Here, the solid content concentration refers to the percentage of the mass of components other than the diluent relative to the total mass of the components at the preparation stage of the resin composition.

[0119] In the step of curing the coating film, the cured transparent resin composition film can be obtained by heat treatment (post-bake) of the coating film. The heat treatment may be performed in air, under a nitrogen atmosphere, or under a vacuum. The heating temperature is preferably 120 to 300°C, and the heating time is preferably 0.25 to 5 hours. The heating temperature may be changed continuously or in steps.

[0120] The coating film may be cured using energy rays. Examples of energy rays include ultraviolet light, visible light, electron beams, and X-rays, but it is preferable to use monochromatic light such as i-line (365 nm), h-line (405 nm), g-line (436 nm) of a mercury lamp, or a UV-LED light source. In particular, when the reactive diluent is used as the diluent, the drying of the reactive diluent and the curing can be performed simultaneously, which is efficient.

[0121] The resin composition and the transparent resin composition film of the present invention can be suitably used, for example, as an overcoat material applied to the curved cover glass surface of a liquid crystal display or an organic EL display. That is, the cover glass of the present invention has the transparent resin composition film of the present invention.

[0122] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples.

[0123] [Correspondence between abbreviations and compound names] PMA: Propylene glycol monomethyl ether acetate PGM: Propylene glycol monoethyl ether MMB: 3-methyl-3-methoxybutanol.

[0124] [Measurement and Evaluation Method] (1) Average Secondary Particle Size The average secondary particle size of colloidal silica, thixotropic agents, and high-refractive index particles obtained from the preparation examples and production examples described below was measured using a dynamic light scattering particle size distribution analyzer (device name: nanoPartica SZ-100S2, manufactured by Horiba, Ltd.). For measurement, each material was diluted 200 times with the solvent PMA. At a measurement temperature of 25°C, under conditions of dispersion medium refractive index 1.40 (PMA), dispersion medium viscosity 1.2 mPa·s (PMA), and scattering angle 173°, each measurement was performed for 10 minutes, and the particle size at which the cumulative frequency in the particle size distribution reached 50% was adopted as the average secondary particle size. After dilution, the sample was stirred for 10 minutes at a rotation speed of 100 rpm using a bench shaker before measurement. The refractive indices were set as follows: 1.46 for silica, 2.52 for titanium oxide, 2.11 for zirconium oxide, and 2.41 for barium titanate.

[0125] (2) Viscosity Stability For the resin composition in its initial state (immediately after manufacturing), the viscosity at 50 rpm and 25°C and the viscosity at 5 rpm (both in Pa·s) were measured using a rotational viscometer (RE-215 model, manufactured by Toki Sangyo Co., Ltd.). Furthermore, for the resin composition after being stored at 23°C for two days from the initial state, and then stored at 50°C for one day (hereinafter referred to as "after storage"), the viscosity at 50 rpm and 5 rpm (both in Pa·s) at 25°C were measured using the same rotational viscometer. When measuring viscosity, depending on the viscosity of the substance being measured, the cone rotor was changed from the standard rotor to one of the following: "1°34 × R12", "0.8° × R24", "3° × R14", or "3° × R17.65". For both 50 rpm and 5 rpm, the viscosity ratio after storage was calculated by dividing the viscosity after storage by the initial viscosity. The following A to E, based on the viscosity ratio after storage, were used as indicators of viscosity stability, and A to D were evaluated as acceptable. A: The viscosity ratio after storage is 0.9 or more and less than 1.1 at both 50 rpm and 5 rpm. B: The viscosity ratio after storage is 0.8 or more and less than 0.9 at one of 50 rpm and 5 rpm, and 0.9 or more and less than 1.1 at the other. C: The viscosity ratio after storage is 0.9 or more and less than 1.1 at one of 50 rpm and 5 rpm, and 1.1 or more and less than 1.2 at the other. D: Outside the range of A to C, and the viscosity ratio after storage is 0.8 or more and less than 1.2 at both 50 rpm and 5 rpm. E: The viscosity ratio after storage is outside the range of 0.8 or more and less than 1.2 at either 50 rpm or 5 rpm.

[0126] Since a higher viscosity after storage tends to cause problems such as clogging of the coating equipment during film formation, we evaluated B as better than C.

[0127] (3) For the resin composition in its initial state (immediately after manufacturing), the viscosity V of the resin composition at 25°C and 50 rpm was measured using a rotational viscometer (RE-215 model manufactured by Toki Sangyo Co., Ltd.). ５０ (Pa·s) and viscosity V at 5 rpm at 25°C ５ (Pa·s) was measured. V ５ V ５０ V obtained by dividing by ５ / V ５０This was defined as the thixotropy ratio of the resin composition.

[0128] (4) Using a precision drill for micro-machining of curved surfaces of resin compositions, a curved surface with a circular recess having a cross-sectional shape as shown in 5 in Figure 1 was formed on the surface of a glass plate made of alkali-free aluminosilicate glass AN100 manufactured by AGC Inc. by polishing, thereby creating a curved glass substrate for evaluation. The inclination angle θ of the cross-sectional shape of the circular recess was set in increments of 2.5° from 10° to 30°, the radius of the corners was 25 mm, the diameter of the outer edge of the bottom was 2 cm, and the depth of the recess was 1.5 mm.

[0129] The resin compositions obtained in each example and comparative example were uniformly applied to the glass substrate having this circular recess using an inkjet method from the top surface of the glass substrate, dried at 80°C, and post-baked at 150°C to form a transparent resin composition film. The ratio of the film thickness t1 at the corner where the transparent resin composition film is thinnest to the film thickness t2 at the bottom edge where the film thickness is thickest is t ２ / t １ The maximum inclination angle among the inclination angles θ (10°, 12.5°, 15°, 17.5°, 20°, 22.5°, 25°, 27.5°, and 30°) where the ratio is 3 or less was defined as the maximum inclination angle. The curved surface processability of the resin compositions of each example and comparative example described below was evaluated using the following indicators A to E, with A to D being considered acceptable. A: The maximum inclination angle θ° is 20° or more and 30° or less. B: The maximum inclination angle θ° is 15° or more and less than 20°. C: The maximum inclination angle θ° is 12.5° or more and less than 15°. D: The maximum inclination angle θ° is 10° or more and less than 12.5°. E: The maximum inclination angle θ° is less than 10°.

[0130] (5) Smoothness The arithmetic mean height Sa value of the surface was measured at the bottom of the circular recess of the transparent resin composition film obtained in each example and comparative example using a laser probe type non-contact three-dimensional measuring device (NH-3SP manufactured by Mitaka Kohki Co., Ltd.) in accordance with ISO 25178, and the following A to D were used as indicators of surface smoothness, with A to C being considered acceptable. A: Sa value is 0.1 μm or less. B: Sa value is greater than 0.1 μm and 0.2 μm or less. C: Sa value is greater than 0.2 μm and 0.3 μm or less. D: Sa value is greater than 0.3 μm.

[0131] (6) Transparency The average total light transmittance at the bottom of the circular recess of the transparent member obtained in each example and comparative example was measured at a measurement wavelength of 400 to 700 nm using a UV-Vis spectrophotometer (UV-2600, manufactured by Shimadzu Corporation). The following A to D were used as indicators of the transparency of the transparent resin composition film, and A to C were considered acceptable. In measuring the average total light transmittance, only a curved glass substrate without the transparent resin composition film was used as a reference. A: The average total light transmittance of the resin composition film is 90% or more. B: The average total light transmittance of the resin composition film is 85% or more and less than 90%. C: The average total light transmittance of the resin composition film is 80% or more and less than 85%. D: The average total light transmittance of the resin composition film is less than 80%.

[0132] (7) A transparent member with a glass surface inclination angle θ of 15° was placed on a support ring (φ35 mm) with the transparent resin composition film facing downwards, and a load ring (φ17.5 mm) was pressed in at a speed of 10 mm / min. The strength at which the curved glass surface broke was measured using a static testing apparatus (AG-Xplus manufactured by Shimadzu Corporation). The following A to D were used as indicators of the glass surface strength of the transparent member, and A to C were considered acceptable. The breaking strength of the curved glass substrate alone without the transparent resin composition film was 800 MPa. A: Breaking strength is 1200 MPa or more. B: Breaking strength is 1000 MPa or more and less than 1200 MPa. C: Breaking strength is 850 MPa or more and less than 1000 MPa. D: Breaking strength is less than 850 MPa.

[0133] (8) The adhesive transparent material was immersed in boiling pure water for 10 minutes, and after drying, the adhesion between the transparent resin composition film and the curved glass substrate was evaluated in accordance with JIS K5400 (1990) 8.5.2 grid tape method. Specifically, 11 parallel lines were drawn vertically and horizontally at 1 mm intervals using a utility knife on the surface of the transparent resin composition film, so as to reach the surface of the curved glass substrate, creating 100 grids of 1 mm x 1 mm. Cellophane adhesive tape (width 18 mm, adhesive strength 3.7 N / 10 mm) was attached to the surface of the transparent resin composition film with the grid, rubbed with an eraser (JIS S6050 approved product) to make it adhere, and the number of remaining grids was visually counted when the tape was instantly peeled off while holding one end perpendicular to the surface of the transparent resin composition film. The peeling area (number) of the grids was used as an indicator of adhesion from A to C below, with A and B being considered acceptable. A: 0 squares have been removed. B: 1 to 5 squares have been removed. C: 6 or more squares have been removed.

[0134] (9) Using a refractive index measuring device (Metricon Model 2010 / M prism coupler), the refractive index of the curved glass substrate and the transparent resin composition film at a wavelength of 633 nm was measured. The following A to D were used as indicators of the preferred refractive index of the transparent resin composition, and A to C were considered acceptable. When measuring the refractive index of the transparent resin composition film, only the glass substrate without the transparent resin composition film was used as a reference. The evaluation was performed using the absolute value of the difference (refractive index of the glass substrate - refractive index of the coating film). The refractive index of the curved glass substrate was 1.536. A: Absolute value of difference is less than 0.005 B: Absolute value of difference is 0.005 or more and less than 0.010 C: Absolute value of difference is 0.010 or more and less than 0.020 D: Absolute value of difference is 0.020 or more and 0.030 or less E: Absolute value of difference is greater than 0.030.

[0135] [Synthesis Example 1: Polysiloxane Resin Solution (A-1)] 48 g of methyltrimethoxysilane, 40 g of phenyltrimethoxysilane, 26 g of 3-trimethoxysilylpropyl succinic acid, 82 g of γ-acryloylpropyltrimethoxysilane, and 180 g of PMA were charged into a 500 mL three-necked flask. The flask was placed in an oil bath at 40°C and stirred while an aqueous phosphoric acid solution, prepared by dissolving 0.4 g of phosphoric acid (0.2 parts by mass relative to the charged monomer) in 55 g of water, was added dropwise over 10 minutes using a dropper funnel. After stirring at 40°C for 1 hour, the oil bath temperature was set to 70°C and stirred for 1 hour, and then the oil bath was heated to 115°C over 30 minutes. One hour after the start of heating, the internal temperature of the solution reached 100°C, and it was heated and stirred for 2 hours thereafter. During the reaction, a total of 120 g of methanol and water, which were by-products, were distilled off to obtain a PMA solution of polysiloxane resin. Furthermore, PMA was added to achieve a polymer concentration of 60% by mass to obtain a polysiloxane resin solution (A-1). The Mw of the obtained polymer was measured by GPC and found to be 2000 in polystyrene equivalent.

[0136] [Synthesis Example 2: Polysiloxane Resin Solution (A-2)] 40 g of methyltrimethoxysilane, 30 g of phenyltrimethoxysilane, 13 g of 3-trimethoxysilylpropyl succinic acid, 117 g of γ-acryloylpropyltrimethoxysilane, and 180 g of PMA were charged into a 500 mL three-necked flask. The flask was placed in an oil bath at 40°C and stirred while an aqueous phosphoric acid solution, prepared by dissolving 0.4 g of phosphoric acid (0.2 parts by mass relative to the charged monomer) in 56 g of water, was added dropwise over 10 minutes using a dropper funnel. After stirring at 40°C for 1 hour, the oil bath temperature was set to 70°C and stirred for 1 hour, and then the oil bath was heated to 115°C over 30 minutes. One hour after the start of heating, the internal temperature of the solution reached 100°C, and it was heated and stirred for 2 hours thereafter. A total of 120 g of methanol and water, which were by-products during the reaction, were distilled off to obtain a PMA solution of polysiloxane resin. Furthermore, PMA was added to achieve a polymer concentration of 60% by mass to obtain a polysiloxane resin solution (A-2). The Mw of the obtained polymer was measured by GPC and found to be 1500 in polystyrene equivalent.

[0137] [Synthesis Example 3: Polysiloxane Resin Solution (A-3)] 48 g of methyltrimethoxysilane, 50 g of phenyltrimethoxysilane, 52 g of 3-trimethoxysilylpropyl succinic acid, 47 g of γ-acryloylpropyltrimethoxysilane, and 180 g of PMA were placed in a 500 mL three-necked flask. The flask was placed in an oil bath at 40°C and stirred while an aqueous phosphoric acid solution, prepared by dissolving 0.4 g of phosphoric acid (0.2 parts by mass relative to the charged monomer) in 56 g of water, was added dropwise over 10 minutes using a dropper funnel. After stirring at 40°C for 1 hour, the oil bath temperature was set to 70°C and stirred for 1 hour, and then the oil bath was heated to 115°C over 30 minutes. One hour after the start of heating, the internal temperature of the solution reached 100°C, and it was heated and stirred for 2 hours thereafter. During the reaction, a total of 120 g of methanol and water, which were by-products, were distilled off to obtain a PMA solution of polysiloxane resin. Furthermore, PMA was added to obtain a polysiloxane resin solution (A-3) with a polymer concentration of 60% by mass. The Mw of the obtained polymer was measured by GPC and found to be 3000 in polystyrene equivalent.

[0138] [Preparation example: Colloidal silica dispersions (B-1) to (B-5)] "PMA-ST" (30% by mass solids, manufactured by Nissan Chemical Industries, Ltd.) was prepared as colloidal silica dispersion (B-1), "IPA-ST" (30% by mass solids, manufactured by Nissan Chemical Industries, Ltd.) as colloidal silica dispersion (B-2), "MIBK-ST" (30% by mass solids, manufactured by Nissan Chemical Industries, Ltd.) as colloidal silica dispersion (B-3), "IPA-ST-L" (30% by mass solids, manufactured by Nissan Chemical Industries, Ltd.) as colloidal silica dispersion (B-4), and "IPA-ST-ZL" (30% by mass solids, manufactured by Nissan Chemical Industries, Ltd.) as colloidal silica dispersion (B-5).

[0139] [Preparation Example 1: Thixotropic Agent Dispersion (C-1)] Hydrophobic fumed silica particles "Rheoroseal® DM-30" (primary particle size 7 nm, manufactured by Tokuyama Corporation) were mixed with PMA as a diluent and dispersed using a small laboratory disperser (CV3-Plus, manufactured by Eiko Seiki Co., Ltd.) to prepare a thixotropic agent dispersion (C-1) with a solid content of 15% by mass. The average secondary particle size of the thixotropic agent was then measured. The results are shown in Table 1.

[0140] [Preparation Example 2: Thixotropic Agent Dispersion (C-2)] A dispersion of a thixotropic agent with a solid content of 15% by mass (C-2) was prepared in the same manner as in Preparation Example 1, except that hydrophilic fumed silica particles "Rheoroseal® QS-30" (primary particle size 7 nm, manufactured by Tokuyama Corporation) were used as the thixotropic agent. The average secondary particle size of the thixotropic agent was then measured. The results are shown in Table 1.

[0141] [Preparation Example 3: Thixotropic Agent Dispersion (C-3)] A dispersion of a thixotropic agent with a solid content of 15% by mass (C-3) was prepared in the same manner as in Preparation Example 1, except that hydrophobic fumed silica particles "AEROSIL® R974" (primary particle size 12 nm, manufactured by Nippon Aerosil Co., Ltd.) were used as the thixotropic agent. The average secondary particle size of the thixotropic agent was then measured. The results are shown in Table 1.

[0142] [Preparation Example 4: Thixotropic Agent Dispersion (C-4)] A dispersion of a thixotropic agent with a solid content of 15% by mass (C-4) was prepared in the same manner as in Preparation Example 1, except that hydrophobic fumed silica particles "AEROSIL® RX200" (primary particle size 12 nm, manufactured by Nippon Aerosil Co., Ltd.) were used as the thixotropic agent. The average secondary particle size of the thixotropic agent was then measured. The results are shown in Table 1.

[0143] [Preparation Example 5: Thixotropic Agent Dispersion (C-5)] A cellulose nanofiber dispersion with a solid content of 2% by mass, "Reocrista® I-2AX" (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), was prepared as the thixotropic agent dispersion (C-5). The average secondary particle size of the thixotropic agent was then measured. The results are shown in Table 2.

[0144] [Preparation Example D1: High Refractive Index Particle Dispersion (D-1)] As high refractive index particles, titanium dioxide ultrafine particles "TTO-V4" (primary particle size 5 nm to 15 nm, manufactured by Ishihara Sangyo Co., Ltd.) were mixed with PMA as a diluent and dispersed using a small laboratory disperser (CV3-Plus, manufactured by Eiko Seiki Co., Ltd.) to prepare a high refractive index particle dispersion (D-1) with a solid content of 80% by mass. The average secondary particle size of the high refractive index particles was then measured. The results are shown in Table 2.

[0145] [Preparation Example D2: High Refractive Index Particle Dispersion (D-2)] As high refractive index particles, zirconium oxide ultrafine particles "Zirconeo-Rp" (primary particle diameter 10 nm or less, manufactured by ITEC Corporation) were mixed with PMA as a diluent and dispersed using a small laboratory disperser (CV3-Plus, manufactured by Eiko Seiki Co., Ltd.) to prepare a high refractive index particle dispersion (D-2) with a solid content of 80% by mass. The average secondary particle diameter of the high refractive index particles was then measured. The results are shown in Table 2.

[0146] [Preparation Example D3: High Refractive Index Particle Dispersion (D-3)] As high refractive index particles, barium titanate particle dispersion "A112BT" (primary particle diameter 0.05 μm, manufactured by Tokushiki Co., Ltd.) was mixed with PMA as a diluent and dispersed using a small laboratory disperser (CV3-Plus, manufactured by Eiko Seiki Co., Ltd.) to prepare a high refractive index particle dispersion (D-3) with a solid content of 80% by mass. The average secondary particle diameter of the high refractive index particles was then measured. The results are shown in Table 2.

[0147] [Example 1: Resin Composition (PB-1)] Using a siloxane resin solution (A-1), a colloidal silica dispersion (B-1), a thixotropic agent dispersion (C-1), and a high refractive index particle dispersion (D-1), 100 parts by mass of siloxane resin was mixed with 95 parts by mass of colloidal silica dispersion (B-1), 85 parts by mass of thixotropic agent dispersion (C-1), 7 parts by mass of solids of "Aronoxetane (registered trademark) OXT-211" (manufactured by Toagosei Co., Ltd.) as a crosslinking agent, and 0.2 parts by mass of solids of surfactant "BYK (registered trademark)-3550" (manufactured by Bic Chemie Japan Co., Ltd.). A mixture of PGM / MMB in a mass ratio of 50 / 50 was added as a diluent (E) to a solid content concentration of 30% by mass, and the mixture was stirred to obtain resin composition (PB-1).

[0148] And the viscosity V of the resin composition (PB-1) ５０ , V ５ The thixotropy ratio was calculated, and the storage stability and curved surface processability were evaluated. Furthermore, a resin composition film (PB-1) was formed on the glass substrate using the resin composition, and the performance of the film was evaluated. The results are shown in Table 3.

[0149] [Examples 2-27: Resin compositions (PB-2)-(PB-27)] Resin compositions (PB-2)-(PB-27) were obtained in the same manner as in Example 1, except that the composition and amounts of siloxane resin, colloidal silica, thixotropic agent, and diluent were changed as shown in Tables 1 and 2. The viscosity V of the resin compositions (PB-2)-(PB-27) was then determined. ５０ 、 V ５ The thixotropy ratio was calculated by measuring the resin composition (PB-2) to (PB-27), and the storage stability and curved surface processability were evaluated. Furthermore, resin composition films were formed on the glass substrate using the resin compositions (PB-2) to (PB-27), and the performance of the films was evaluated. The results are shown in Tables 3 and 4.

[0150] [Example 28: Resin Composition (PB-28)] Resin composition (PB-28) was obtained in the same manner as in Example 1, except that the composition and amounts of siloxane resin, colloidal silica, thixotropic agent, and diluent were changed as shown in Table 2, and 19 parts by mass of high refractive index particle dispersion (D-1) was added. The viscosity V of the resin composition (PB-28) was then determined. ５０ 、 V ５ The thixotropy ratio was calculated by measuring the resin composition, and the storage stability and curved surface processability were evaluated. Furthermore, a resin composition film (PB-28) was formed on the glass substrate using the resin composition, and the performance of the film was evaluated. The results are shown in Table 4.

[0151] [Examples 29-33: Resin compositions (PB-29)-(PB-33)] Resin compositions (PB-29)-(PB-33) were obtained in the same manner as in Example 24, except that the composition and amounts of siloxane resin, colloidal silica, thixotropic agent, high refractive index particle dispersion, and diluent were changed as shown in Table 2. The viscosity V of the resin compositions (PB-29)-(PB-33) was then determined. ５０ 、 V ５ The thixotropy ratio was calculated by measuring the resin composition (PB-29) to (PB-33), and the storage stability and curved surface processability were evaluated. Furthermore, resin composition films were formed on the glass substrate using the resin compositions (PB-29) to (PB-33), and the performance of the films was evaluated. The results are shown in Table 4.

[0152] [Comparative Examples 1-7: Resin Compositions (PBH-1)-(PBH-7)] Resin compositions (PBH-1)-(PBH-7) were obtained in the same manner as in Example 23, except that the composition and amounts of siloxane resin, colloidal silica, thixotropic agent, high refractive index particle dispersion, and diluent were changed as shown in Table 2.

[0153] The resin compositions (PBH-1) to (PBH-7) of each of the above comparative examples were evaluated using the same method as described in the examples above. The results are shown in Table 4.

[0154] The resin compositions of each example exhibited minimal dripping even on curved surfaces where application is difficult, allowing for efficient application across the entire surface of the curved glass substrate. The resulting transparent resin film had a generally smooth surface and high transparency. Furthermore, the resulting curved glass exhibited high glass surface strength.

[0155]

[0156]

[0157]

[0158]

[0159] The resin composition and transparent resin composition film of the present invention can be suitably used, for example, as an overcoat material applied to the curved cover glass surface of liquid crystal displays and organic EL displays.

[0160] 1 Transparent resin composition film 5 Curved glass substrate 10 Curved portion 11 Corner portion 12 Side portion 13 Bottom portion 20 Edge of bottom portion 30 Flat portion 50 Curved glass t1 Film thickness of transparent resin composition film near the corner portion t2 Film thickness of transparent resin composition film near the edge of the bottom portion θ Inclination angle at the rising portion

Claims

1. A resin composition comprising a siloxane resin, colloidal silica, and a thixotropic agent, wherein the average secondary particle diameter of the colloidal silica is 10 to 100 nm, the average secondary particle diameter of the thixotropic agent is 50 to 500 nm, and the ratio of the average secondary particle diameter of the colloidal silica to the average secondary particle diameter of the thixotropic agent is 0.02 or more and less than 0.67 or greater than 1.5 and less than or equal to 2.

0.

2. Viscosity V measured using a rotational viscometer at 25°C and 5 rpm. ５ The viscosity V is measured using a rotational viscometer at 25°C and 50 rpm. ５０ The thixotropic ratio V is calculated by dividing by [the specified factor]. ５ / V ５０ The resin composition according to claim 1, wherein the ratio is 1.25 or more and 4.00 or less.

3. The resin composition according to claim 1 or 2, which is for inkjet coating.

4. The resin composition according to claim 1, wherein both the colloidal silica and the thixotropic agent are amorphous.

5. The resin composition according to claim 1, wherein the thixotropic agent is cellulose nanofiber or fumed silica.

6. The resin composition according to claim 1 or 2, comprising 5 to 35 parts by mass of the thixotropizing agent per 100 parts by mass of the siloxane resin.

7. The resin composition according to claim 1, comprising 10 to 100 parts by mass of colloidal silica per 100 parts by mass of the siloxane resin.

8. The resin composition according to claim 5 or 6, wherein the thixotropic agent is the fumed silica having a hydrophobic surface.

9. The resin composition according to claim 1 or 2, further containing high refractive index particles.

10. The resin composition according to claim 9, wherein the high refractive index particles are one or more selected from zirconium oxide, titanium oxide, and barium titanate.

11. The resin composition according to claim 9, wherein the average secondary particle diameter of the high refractive index particles is 10 to 100 nm.

12. The resin composition according to claim 9, comprising 15 to 100 parts by mass of the high refractive index particles per 100 parts by mass of the siloxane resin.

13. A transparent resin composition film formed on a curved glass surface, comprising a siloxane resin, colloidal silica, and a thixotropic agent.

14. The transparent resin composition film according to claim 13, wherein the curved glass is a curved glass having a raised portion formed on its outer edge, and the product of the inclination angle θ (degrees) of the raised portion and the height h (mm) of the raised portion is 0.03 to 30.

15. A transparent resin composition film comprising a cured product of the resin composition described in claim 1.

16. A cover glass having a transparent resin composition film according to any one of claims 13 to 15.

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