Primer layer–forming composition

Abstract

The present invention provides a composition capable of forming a primer layer having high transparency and a high refractive index. The present invention pertains to a primer layer–forming composition containing an elemental zirconium–containing metal oxide (A) and an aqueous urethane resin (B), wherein: the elemental zirconium–containing metal oxide (A) has an average particle diameter of 1-20 nm as measured by means of a dynamic light scattering method; the pH of a 30 mass% aqueous dispersion of the elemental zirconium–containing metal oxide (A) is 8-11; and the elemental silicon content is 20 mol% or less with respect to 100 mol% of the elemental zirconium in (A).

Description

Primer layer forming composition

[0001] The present invention relates to a primer layer-forming composition, and more particularly to a primer layer-forming composition useful for lenses such as eyeglasses.

[0002] In recent years, plastic lenses have become mainstream for eyeglass lenses due to their lightweight nature, excellent impact resistance, and ease of processing. Plastic lenses have the disadvantage of being easily scratched, so a hard coat layer is formed on the surface of the lens substrate. Poor adhesion between the lens substrate and the hard coat layer can lead to cracking and reduced impact resistance. Therefore, a primer layer is provided between the lens substrate and the hard coat layer to improve adhesion and impact resistance. However, if the refractive index of the primer layer does not match the refractive index of the lens substrate, interference fringes occur due to optical interference, impairing the appearance. Therefore, techniques have been proposed for matching the refractive index of the primer layer to that of the lens substrate. For example, Patent Document 1 proposes a coating solution for use in a primer layer. The coating solution contains surface-modified inorganic complex oxide microparticles, which have a carbon atom content of 2 to 10 wt %, and are obtained by surface-modifying inorganic complex oxide microparticles with an organosilicon compound A represented by a predetermined formula or a partial hydrolyzate thereof, and an organosilicon compound B represented by a predetermined formula or a partial hydrolyzate thereof, which has a boiling point of 120°C or less at 1 atmosphere.

[0003] JP 2014-152226 A

[0004] As mentioned above, although technologies for forming a primer layer on a lens have been developed, the refractive index of plastic lens substrates is increasing due to the growing need for thinner and lighter lenses. When the surface of inorganic complex oxide fine particles is coated with another element such as silicon, as in Patent Document 1, the refractive index of the inorganic complex oxide fine particles decreases, making it difficult to apply to high-refractive-index plastic lens substrates. Therefore, there has been a demand for a composition for forming a primer layer that has a high refractive index and high transparency.

[0005] The present invention has been made in view of the above-mentioned current situation, and has an object to provide a composition capable of forming a primer layer having high transparency and a high refractive index.

[0006] The present inventors have conducted extensive research into compositions for forming primer layers on lenses and the like, and have found that a primer layer having high transparency and a high refractive index can be formed on a lens by using a zirconium-containing metal oxide in a composition containing a zirconium-containing metal oxide and an aqueous urethane resin, the zirconium-containing metal oxide having a silicon content of 20 mol % or less relative to 100 mol % of zirconium in (A), an average particle size within a predetermined range, and a pH of 8 to 11 in a 30 mass % aqueous dispersion. This led to the realization that the above-mentioned problems could be successfully solved, and has led to the present invention.

[0007] The present invention includes the following primer layer-forming compositions, etc.: [1] A primer layer-forming composition comprising a zirconium-containing metal oxide (A) and an aqueous urethane resin (B), wherein the zirconium-containing metal oxide (A) has an average particle size of 1 to 20 nm as measured by dynamic light scattering, a 30 mass% aqueous dispersion of the zirconium-containing metal oxide (A) has a pH of 8 to 11, and the silicon content is 20 mol% or less relative to 100 mol% of zirconium in (A). [2] The primer layer-forming composition according to [1] above, wherein the zirconium-containing metal oxide (A) is contained in an amount of 40 to 80 mass% relative to 100 mass% of the solids content of the primer layer-forming composition. [3] The primer layer-forming composition according to [1] or [2] above, wherein the solid content in the aqueous urethane resin (B) is 20 to 60% by mass, relative to 100% by mass of the solid content in the primer layer-forming composition. [4] The primer layer-forming composition according to any one of [1] to [3] above, which is used for lenses. [5] A lens coated with the primer layer-forming composition according to any one of [1] to [3] above. [6] A method for producing a primer layer-forming composition, the method comprising the step of mixing a zirconium-containing metal oxide (A) with an aqueous urethane resin (B), wherein the zirconium-containing metal oxide (A) has an average particle size of 1 to 20 nm as measured by dynamic light scattering and a pH of 8 to 11 when dispersed in 30% by mass in water.

[0008] The composition for forming a primer layer of the present invention has the above-mentioned configuration and can form a primer layer that is highly transparent and has a high refractive index, and therefore can be suitably used for primer layers for lenses, etc.

[0009] Preferred embodiments of the present invention will be specifically described below, but the present invention is not limited to the following description and can be appropriately modified and applied within the scope of the present invention. Note that a combination of two or more of the individual preferred embodiments of the present invention described below also falls within the scope of the present invention.

[0010] [Primer Layer-Forming Composition] The primer layer-forming composition of the present invention is a primer layer-forming composition comprising a zirconium-containing metal oxide (A) and an aqueous urethane resin (B), wherein the zirconium-containing metal oxide (A) has an average particle size of 1 to 20 nm as measured by dynamic light scattering, a pH of a 30 mass% aqueous dispersion of the zirconium-containing metal oxide (A) is 8 to 11, and the silicon content is 20 mol% or less relative to 100 mol% of zirconium in (A). The primer layer-forming composition of the present invention has excellent transparency because the pH of a 30 mass% aqueous dispersion of the zirconium-containing metal oxide (A), which is a raw material before addition to the composition, is in the above-mentioned range, and the average particle size of the zirconium-containing metal oxide (A) is in the above-mentioned range, and therefore has a high refractive index. Since the primer layer-forming composition of the present invention has the above-mentioned structure, the primer layer formed on a lens or the like using the composition is excellent in solvent resistance, adhesion, weather resistance, and impact resistance.

[0011] The primer layer-forming composition of the present invention has a silicon content of 20 mol% or less relative to 100 mol% of zirconium in the zirconium-containing metal oxide (A). This allows the refractive index to be sufficiently increased. The silicon content is preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 1 mol% or less, particularly preferably 0.1 mol% or less, and most preferably 0 mol%.

[0012] In the primer layer-forming composition, the content of the zirconium-containing metal oxide (A) is preferably 40 to 80 mass%, more preferably 43 to 75 mass%, even more preferably 44 to 73 mass%, and particularly preferably 45 to 70 mass%, relative to 100 mass% of the solids (non-volatile content) in the primer layer-forming composition.

[0013] In the primer layer-forming composition, the content of the solids in the aqueous urethane resin (B) is preferably 20 to 60% by mass, more preferably 25 to 57% by mass, even more preferably 27 to 56% by mass, and particularly preferably 30 to 55% by mass, relative to 100% by mass of the solids in the primer layer-forming composition.

[0014] In the primer layer-forming composition, the solid content of the aqueous urethane resin (B) is preferably 25 to 150 mass %, more preferably 30 to 145 mass %, even more preferably 35 to 140 mass %, and particularly preferably 40 to 130 mass %, relative to 100 mass % of the zirconium-containing metal oxide (A).

[0015] The primer layer-forming composition preferably contains a solvent to adjust the solids concentration of the primer layer-forming composition. The solids concentration of the primer layer-forming composition is not particularly limited, but is preferably 5 to 50 mass %, more preferably 5 to 45 mass %, even more preferably 6 to 40 mass %, and particularly preferably 7 to 30 mass %. The proportion of the solvent in the primer layer-forming composition is preferably the value obtained by subtracting the solids concentration from 100 mass % of the composition.

[0016] The primer layer-forming composition of the present invention may contain other components in addition to the zirconium-containing metal oxide (A), the aqueous urethane resin (B), and the solvent. The content of the other components is not particularly limited, but is preferably 0 to 30% by mass relative to 100% by mass of the solids content of the primer layer-forming composition. It is more preferably 0 to 28% by mass, even more preferably 0 to 25% by mass, and particularly preferably 0 to 20% by mass.

[0017] The primer layer-forming composition of the present invention preferably has a refractive index of 1.55 to 1.74 when the composition is cured to a thickness of 1 μm. The refractive index is preferably 1.58 to 1.70. The refractive index of the cured film can be measured by the method described in the examples.

[0018] The primer layer-forming composition of the present invention preferably has a total light transmittance of 94.0 to 100.0% when the composition is cured into a film having a thickness of 3 μm. The total light transmittance is preferably 95.0 to 100.0%. The total light transmittance of the cured film can be measured by the method described in the Examples.

[0019] The essential components and optional components contained in the composition for forming a primer layer of the present invention will be further described below.

[0020] <Zirconium-containing metal oxide (A)> The zirconium-containing metal oxide (A) is not particularly limited as long as it contains zirconium atoms and oxygen atoms, and may contain elements other than zirconium atoms and oxygen atoms. Examples of other elements include silicon, as described above, as well as at least one stabilizing element selected from sodium, magnesium, aluminum, potassium, titanium, hafnium, and rare earth elements. When the zirconium-containing metal oxide (A) contains the stabilizing element, the thermal stability of the metal oxide (A) is further improved. Specific examples of the rare earth elements include Y, La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Ho.

[0021] The content of the other elements in the zirconium-containing metal oxide (A) is not particularly limited as long as the content of the other elements in the composition is 20 mol% or less relative to 100 mol% of zirconium element, but is preferably 0 to 20 mol% relative to 100 mol% of zirconium element, more preferably 0 to 10 mol%, and even more preferably 0 to 5 mol%. In one embodiment, the content of the other elements may be a proportion greater than 0 mol%.

[0022] The zirconium-containing metal oxide (A) has an average particle size (D50) of 1 to 20 nm in a dispersion state, as measured by dynamic light scattering. When the average particle size is 1 nm or more, aggregation of primary particles can be sufficiently suppressed. Furthermore, when the average particle size is 20 nm or less, a decrease in the transparency of the primer layer can be sufficiently suppressed. The average particle size is more preferably 1 to 19 nm, more preferably 1 to 18 nm, and even more preferably 2 to 17 nm. Furthermore, the D50 / D90 of the zirconium-containing metal oxide is more preferably 0.2 to 1.0, and even more preferably 0.3 to 1.0. By using a zirconium-containing metal oxide having a small average particle size (D50) and a narrow particle size distribution, the resulting primer layer-forming composition has higher transparency.

[0023] The zirconium-containing metal oxide (A) may be surface-treated with an inorganic or organic compound. Examples of the inorganic compound include silicon oxide and aluminum oxide. Examples of the organic compound include silane coupling agents, titanate coupling agents, and surfactants having an acidic group such as a phosphate group, a carboxylic acid group, or a phosphonic acid group.

[0024] The zirconium-containing metal oxide (A) has a pH of 8 to 11 in a 30% by mass aqueous dispersion before being added to the composition. This improves the transparency of the resulting primer layer. The pH is more preferably 8.5 to 11, and even more preferably 9 to 11. The pH can be measured at room temperature (25°C) using a pH meter with a glass electrode.

[0025] The form of the zirconium-containing metal oxide (A) is not particularly limited, but it is preferably crystalline. The crystal structure is preferably a cubic crystal, a tetragonal crystal, a monoclinic crystal, or the like, and a plurality of crystal structures may be present. When the form of the zirconium-containing metal oxide (A) includes the above crystal structure, the refractive index and hardness of the zirconium-containing metal oxide (A) are further improved.

[0026] The method for producing the zirconium-containing metal oxide (A) is not particularly limited, and examples thereof include a method in which an aqueous zirconium salt solution is heated and hydrolyzed (hydrolysis method), a method in which an alkali is added to an aqueous zirconium salt solution to form zirconium hydroxide, which is then peptized (neutralization coprecipitation method), and a method in which an acid and an alkali are added to zirconium hydroxide, followed by hydrothermal treatment (hydrothermal synthesis method).

[0027] A preferred method for producing the zirconium-containing metal oxide (A) includes a neutralization coprecipitation step of adding an alkali to an aqueous solution containing a zirconium salt to form a hydroxide, which is then peptized, and a hydrothermal step of adding an acid or a salt thereof to the product obtained in the neutralization coprecipitation step and subjecting it to hydrothermal treatment.

[0028] The zirconium salt used in the neutralization coprecipitation step is not particularly limited as long as it contains zirconium element, but chlorides, oxychlorides, sulfates, nitrates, etc. are preferred. Chlorides and oxychlorides are more preferred. Zirconium compounds used as raw materials in the production of a slurry containing a zirconium element-containing compound include hydroxides, hydroxide oxides, chlorides, sulfides, sulfates, nitrates, carbonates, hydrogencarbonates, acetates, phosphates, oxalates, butyrates, selenates, iodates, fluorides, oxychlorides, etc. Among these, oxychlorides, chlorides, sulfates, nitrates, acetates, etc., which are water-soluble zirconium compounds suitable for production, are preferred.

[0029] When the zirconium-containing metal oxide (A) contains elements other than zirconium and oxygen, it is preferable to add salts of the other elements in the neutralization coprecipitation step, such as chlorides, oxychlorides, sulfates, nitrates, and acetates.

[0030] The alkali used in the neutralization coprecipitation step is not particularly limited, and examples thereof include hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide, and calcium hydroxide; ammonia; organic amines; etc. Among these, hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide are preferred.

[0031] The amount of alkali used in the neutralization coprecipitation step is not particularly limited, but is preferably 10 to 1,000 mol % relative to 100 mol % of the total of zirconium element and the other elements.

[0032] The acid or salt thereof used in the hydrothermal step is not particularly limited, and examples thereof include inorganic acids such as phosphoric acid, and organic acids such as formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, lactic acid, malic acid, tartaric acid, citric acid, and gluconic acid, and salts thereof. Among these, organic acids and salts thereof are preferred.

[0033] The amount of acid or its salt used in the hydrothermal step is not particularly limited, but is preferably 50 to 1,000 mol %, more preferably 100 to 500 mol %, relative to 100 mol % of the total of zirconium element and the other elements.

[0034] The hydrothermal temperature in the hydrothermal step is not particularly limited, but is preferably 170 to 230°C, and more preferably 175 to 220°C.

[0035] The hydrothermal treatment time in the hydrothermal step is not particularly limited, but is preferably 1 to 10 hours, more preferably 1.5 to 6 hours.

[0036] The method for producing the zirconium-containing metal oxide (A) preferably includes a washing step after the neutralization coprecipitation step and / or the hydrothermal step. The washing method in the washing step is not particularly limited, and can be performed by a commonly used method. For example, after the neutralization coprecipitation step, a washing method such as filtration and water washing is preferred. Furthermore, after the hydrothermal step, it is preferred to use an ultrafiltration membrane or the like.

[0037] When the zirconium-containing metal oxide (A) is produced by the above-mentioned production method, it is obtained as an aqueous dispersion, and therefore, when used in the primer layer-forming composition of the present invention, it may be substituted with an organic solvent.

[0038] The organic solvent is not particularly limited, but examples thereof include those having good compatibility with water, such as alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone; esters such as ethyl lactate; polyhydric alcohols and their ethers such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate; and cyclic ethers such as dioxane and tetrahydrofuran. These can be used alone or in combination. Ketones such as acetylacetone, methyl ethyl ketone, and methyl isobutyl ketone, esters such as ethyl acetate and butyl acetate, and aromatic hydrocarbons such as benzene and toluene, which are also compatible with these organic solvents, can also be used in combination as appropriate. Among these, lower alcohols having 1 to 3 carbon atoms are preferred. Methanol is more preferred.

[0039] <Water-based Urethane Resin (B)> The water-based urethane resin (B) contained in the primer layer-forming composition of the present invention is not particularly limited as long as it is a polymer having a urethane bond containing water. For example, a self-emulsifying water-based urethane resin having a hydrophilic group such as an anionic group, a cationic group, or a nonionic group; a forced-emulsifying water-based urethane resin forcibly dispersed in water with an emulsifier, etc. can be used. Among these, it is preferable to use a self-emulsifying water-based urethane resin. The average particle size of the water-based urethane resin is preferably 0.06 μm or less. Note that commercially available water-based urethane resins can also be used. Examples of commercially available products include the Evaphanol series manufactured by Nicca Chemical Co., Ltd., the Superflex series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and the Adeka Bontitor series manufactured by ADEKA Corporation.

[0040] Specific examples of the aqueous urethane resin (B) include non-yellowing isocyanate-polyester aqueous urethane resins, non-yellowing isocyanate-polyether aqueous urethane resins, non-yellowing isocyanate-polycarbonate aqueous urethane resins, non-yellowing isocyanate-polyester / ether aqueous urethane resins, non-yellowing isocyanate-polyester / polycarbonate aqueous urethane resins, aromatic isocyanate-polyester aqueous urethane resins, aromatic isocyanate-polyether aqueous urethane resins, aromatic isocyanate-polycarbonate aqueous urethane resins, aromatic isocyanate-polyester / ether aqueous urethane resins, aromatic isocyanate-polyester / polycarbonate aqueous urethane resins, etc. Among these, non-yellowing aqueous urethane resins are preferred, as they provide superior solvent resistance and weather resistance. More preferred examples of the aqueous urethane resin (B) include non-yellowing isocyanate-polyester aqueous urethane resins, non-yellowing isocyanate-polyester / ether aqueous urethane resins, and non-yellowing isocyanate-polycarbonate aqueous urethane resins.

[0041] The solvent that can be used in the primer layer-forming composition of the present invention is not particularly limited, and examples thereof include water and organic solvents. The type of organic solvent is not particularly limited, and examples thereof include alcohol solvents, ketone solvents, ether solvents, ester solvents, hydrocarbon solvents, halogenated hydrocarbon solvents, amide solvents, sulfone solvents, and sulfoxide solvents. The solvent is preferably water and / or a water-soluble organic solvent, and may be a mixed solvent of water and a water-soluble organic solvent. The solvent is more preferably water, methanol, ethanol, isopropanol, or propylene glycol monomethyl ether.

[0042] The water-soluble organic solvent is an organic solvent that is compatible with water, and more specifically, it means an organic solvent that has a solubility in water of 10% by mass or more, preferably 50% by mass or more at 25°C. Examples of water-soluble organic solvents include alcohols such as methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, trimethylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,4-butenediol, and hexylene glycol; polyhydric alcohols and ethers thereof such as ethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether (1-methoxy-2-propanol), propylene glycol mono-n-propyl ether, and propylene glycol monomethyl ether acetate; ketones such as acetone, diacetone alcohol, and acetylacetone; and amides such as N-methyl-2-pyrrolidone.

[0043] The primer layer-forming composition of the present invention may contain other components in addition to the zirconium-containing metal oxide (A), the aqueous urethane resin (B), and the solvent. The other components are not particularly limited, and include various additives such as oxides of metals other than zirconium, dispersants, surface treatment agents, leveling agents, crosslinking agents, chelating agents, antistatic agents, antifoaming agents, flame retardants, UV absorbers, antioxidants, coating film conditioners, light stabilizers, antioxidants, color inhibitors, and dyes.

[0044] Examples of the oxides of metals other than zirconium include oxides of metals such as Ti, Al, Sn, Sb, Ta, Ce, La, Fe, Zn, and W. Preferred examples of the oxides of metals other than zirconium include titanium oxide, antimony oxide, zinc oxide, and cerium oxide, and may also be composite oxides of these. These are commercially available, and examples of commercially available products include sols in which particles containing these metal oxides are dispersed in water or an organic solvent.

[0045] Examples of the dispersant include anionic surfactants such as sulfate ester type, carboxylic acid type, and phosphate ester type, cationic surfactants such as quaternary ammonium type, nonionic surfactants such as alkyl ether type, amphoteric surfactants such as alkyl betaine type, and polymer type surfactants.

[0046] Examples of the leveling agent include silicone-based leveling agents, fluorine-based leveling agents, acrylic-based leveling agents, and acrylic silicone-based leveling agents.

[0047] [Method for producing a primer layer-forming composition] The present invention is also a method for producing a primer layer-forming composition, which includes a step of mixing a zirconium-containing metal oxide (A) with an aqueous urethane resin (B), wherein the zirconium-containing metal oxide (A) has an average particle size of 1 to 20 nm as measured by dynamic light scattering, and a pH of 8 to 11 when the zirconium-containing metal oxide (A) is dispersed in a 30% by mass aqueous solution.

[0048] The step of mixing the zirconium-containing metal oxide (A) and the aqueous urethane resin (B) is not particularly limited as long as the zirconium-containing metal oxide (A) and the aqueous urethane resin (B) are mixed, and mixing by stirring or the like is preferred.

[0049] The zirconium-containing metal oxide (A) used in the mixing step has an average particle size of 1 to 20 nm as measured by dynamic light scattering, and a pH of 8 to 11 when it is made into a 30% by mass aqueous dispersion. The method for producing the zirconium-containing metal oxide (A) is as described above, and it is sufficient that the zirconium-containing metal oxide (A) before being mixed with the aqueous urethane resin (B) has a pH of 8 to 11 when it is made into a 30% by mass aqueous dispersion, and when it is mixed with the aqueous urethane resin (B), an organic solvent such as methanol may be substituted for the zirconium-containing metal oxide (A).

[0050] The amounts of the zirconium-containing metal oxide (A) and the aqueous urethane resin (B) used in the mixing step are not particularly limited, and they are preferably added so as to achieve the above-mentioned preferred ratio in the primer layer-forming composition.

[0051] [Uses of Primer Layer-Forming Composition] The primer layer-forming composition of the present invention can be suitably used for a primer layer (primer film) between a lens substrate and a hard coat layer in optical plastics such as lenses. The present invention also relates to a lens coated with the primer layer-forming composition, i.e., a lens on which a primer layer is provided using the primer layer-forming composition.

[0052] The method for forming the primer layer is not particularly limited, and known methods such as dipping, spin coating, flow coating, and spraying can be used. The primer layer applied to the lens surface using such a method is then cured by thermal energy (heat conduction, convection, radiation). For example, when curing is performed in a thermal environment with hot air convection, the curing conditions are preferably an ambient temperature of 80°C to 130°C for 5 to 180 minutes.

[0053] The lens is not particularly limited as long as it has a primer film formed thereon using the primer layer-forming composition, but it is preferable that the lens has a primer film formed on a lens substrate and a hard coat film containing a coating composition formed on the outer layer thereof. It is also preferable that the lens further has an anti-reflection film or an antifouling coat laminated thereon.

[0054] The coating composition is not particularly limited as long as it is a commonly used composition, and examples thereof include compositions containing inorganic particles such as inorganic oxide fine particles, hydrolyzable group-containing organosilicon compounds (silane coupling agents), their hydrolysates, or their hydrolyzed condensates.

[0055] Examples of the hydrolyzable group-containing organosilicon compound include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, tetraethoxysilane, methyltriethoxysilane, 1,2-bis(triethoxysilyl)ethane, vinyltrimethoxysilane, and (meth)acryloxypropyltrimethoxysilane.

[0056] Examples of inorganic oxide fine particles include oxide fine particles of zirconium, silicon, tin, titanium, cerium, etc., and composite fine particles of these.

[0057] The refractive index of the lens is preferably 1.50 to 1.74, and more preferably 1.60 to 1.67.

[0058] The lens preferably has a haze of 0.5% or less, more preferably 0.4% or less, as measured by a haze meter.

[0059] As the material for the lens, plastic lenses having a molecular structure of aliphatic allyl carbonate-based, polyamide-based, polyurea-based, methacrylate-based, aromatic allyl carbonate-based, polycarbonate-based, polyurethane-based, polythiourethane-based, episulfide-based, or thioepoxy-based resins are commercially available, and these can be suitably used. The use of the primer layer-forming composition of the present invention for plastic lenses is one of the preferred embodiments of the present invention.

[0060] The lens is not particularly limited, but is preferably used for eyeglasses. The embodiment in which the lens is an eyeglass lens is one of the preferred embodiments of the present invention.

[0061] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass."

[0062] <Evaluation of Physical Properties> The physical properties of the obtained zirconium-containing metal oxide (A) and primer layer-forming composition were evaluated according to the following procedures.

[0063] <Average Particle Diameter of Zirconium-Containing Metal Oxide> The average particle diameter of the zirconium-containing metal oxide in a dispersion of the oxide was measured by dynamic light scattering (UPA-UT manufactured by Nikkiso Co., Ltd.), and the values ​​of D50, D90, and Dmax were calculated.

[0064] <pH of Zirconium-Containing Metal Oxide Dispersion> The pH of a 30 mass % aqueous dispersion of zirconium-containing metal oxide was measured at room temperature (25° C.) using a pH meter with a glass electrode.

[0065] <Weight change (%) of water-based polyurethane resin before and after solvent resistance test> The weight change (%) of the resin before and after the solvent resistance test was determined according to the following steps 1) to 7). 1) Weigh the tared weight of a slide glass substrate measuring 76 x 26 mm and 1.2 to 1.5 mm thick (W ０ 2) The resin is applied to the slide glass substrate by dipping at a speed of 130 mm / min. 3) The slide glass substrate to which the resin has been applied is heated at 90°C for 10 minutes. 4) After heating, the tare weight of the slide glass substrate is measured (W １ 5) Immerse the slide glass substrate in a solution of methanol:propylene glycol monomethyl ether = 3:1 at 25°C for 10 minutes. 6) After immersion, measure the tared weight of the slide glass substrate (W ２ 7) The W obtained above １ , W ２ The weight change rate is calculated by substituting the value of the following formula: Weight change rate = [(W ２ -W １ ) / (W １ -W ０ ) × 100

[0066] <Haze and Total Light Transmittance of Cured Film of Primer Layer-Forming Composition> The haze and total light transmittance of the cured film of the primer layer-forming composition were measured using a haze meter (NDH4000, manufactured by Nippon Denshoku Industries Co., Ltd.). Samples for measuring the haze and total light transmittance of the cured film of the primer layer-forming composition were prepared using the following procedures 1) to 3). 1) In the method for preparing the primer layer-forming composition described in the Examples and Comparative Examples, the amount of water added was reduced to adjust the solids concentration of the primer layer-forming composition to 22.5 mass%. 2) The primer layer-forming composition obtained in procedure 1) above was applied to a slide glass substrate by dipping at a speed of 130 mm / min. 3) After application, the slide glass substrate was heated at 90°C for 10 minutes to cure, forming a 3 μm-thick cured film of the primer layer-forming composition on the slide glass substrate for measuring haze and total light transmittance.

[0067] <Refractive Index of Cured Film (Primer Layer) of Primer Layer-Forming Composition> The refractive index of the cured film (primer layer) of the primer layer-forming composition obtained in the examples and comparative examples was measured using a spectroscopic film thickness meter (F20 manufactured by Filmetrics Inc.).

[0068] <Confirmation of Contamination of the Cured Film of the Primer Layer-Forming Composition with the Hard Coat (HC) Liquid> The presence or absence of contamination of the cured film of the primer layer-forming composition with the hard coat liquid was confirmed by the following procedures 1) to 5). 1) The primer layer-forming composition was applied to the lens substrate by dipping at a speed of 130 mm / min. 2) The lens substrate coated with the primer layer-forming composition was heated at 90°C for 10 minutes for pre-curing, forming a primer layer with a thickness of 1 μm on the lens substrate. 3) The hard coat liquid described in Production Example 6 was applied to the lens substrate coated with the primer layer-forming composition by dipping at a speed of 130 mm / min. 4) The lens substrate coated with the hard coat liquid was pre-cured by heating at 90°C for 10 minutes, and then heated at 120°C for 2 hours for full curing, forming a hard coat layer with a thickness of 3 μm. 5) The appearance of the lens substrate coated with the primer layer and hard coat layer was visually evaluated according to the following criteria. ◯: No cloudiness, ×: Cloudiness.

[0069] <Adhesion of cured film of primer layer-forming composition> The surface of a lens substrate coated with a primer layer and a hard coat layer was scored with a knife at 1 mm intervals to form 100 1 mm square grids, and a cellophane adhesive tape was pressed firmly against these grids and then suddenly pulled in a direction at an angle of 90 degrees relative to the in-plane direction of the lens substrate. This operation was repeated 10 times in total, and the number of grids that had not peeled off was counted and evaluated according to the following criteria: ◯: The number of grids that had not peeled off was 95 or more, ×: The number of grids that had not peeled off was less than 95.

[0070] <Impact Resistance of Cured Film of Primer Layer-Forming Composition> An antireflection layer was formed on a lens substrate coated with a primer layer and a hard coat layer. The formation of the antireflection layer was outsourced to Nidek Co., Ltd. A 16.2 g steel ball was dropped from a height of 127 cm onto the center of the lens substrate coated with the primer layer, hard coat layer, and antireflection layer, and the lens substrate was visually evaluated for damage according to the following criteria: ◯: No breaks or cracks in the lens substrate or coating; ×: The lens substrate or coating was damaged.

[0071] <Appearance of cured film of primer layer-forming composition after weather resistance test> The lens substrate coated with the primer layer and hard coat layer was visually inspected for appearance after 40 hours using a xenon testing machine (Ci4000 manufactured by ATLAS) in accordance with ISO 4892-2, and evaluated according to the following criteria: ◯: No change in transparency and no discoloration observed, ×: Transparency decreased.

[0072] <Adhesion of cured film of primer layer-forming composition after weather resistance test> The lens substrate coated with the primer layer and hard coat layer was evaluated for adhesion after 40 hours using a xenon testing machine (Ci4000 manufactured by ATLAS) in accordance with ISO 4892-2, using the following criteria: ◯: Number of unpeeled squares is 95 or more, ×: Number of unpeeled squares is less than 95.

[0073] (Production Example 1: Preparation of Zirconium-Containing Metal Oxide Aqueous Dispersion (A)) 0.76 L of a mixed aqueous solution of 0.6 mol / L zirconium oxychloride and 0.03 mol / L yttrium chloride and 0.53 L of a 1.9 mol / L sodium hydroxide aqueous solution were prepared. The mixed aqueous solution of zirconium oxychloride and yttrium chloride and the sodium hydroxide aqueous solution were simultaneously poured into a precipitation reactor containing 0.74 L of pure water, and the zirconium oxychloride and yttrium chloride were co-precipitated by simultaneous neutralization to obtain a slurry of coprecipitate particles of zirconium oxide and yttrium. The obtained slurry was filtered, washed, and repulped in pure water so that the solid content of the slurry was 5.6 mass% in terms of zirconium oxide and yttrium oxide, obtaining 1 L of slurry. The electrical conductivity of this slurry was 235 μS / cm. To the slurry, 140.8 g of sodium citrate dihydrate (1 molar amount per 1 molar amount of the total amount of zirconium and yttrium in the slurry) was added, followed by hydrothermal treatment for 3 hours at 200° C. to obtain a translucent dispersion. This translucent dispersion was washed and concentrated using an ultrafiltration membrane to obtain an aqueous dispersion (A) of zirconium-containing metal oxide, which is a solid solution containing 5.0 mol % of yttrium and has a zirconium-containing metal oxide content of 30 mass %.

[0074] (Production Example 2: Preparation of methanol dispersion (B) of zirconium-containing metal oxide) 10 kg of the aqueous dispersion (A) of zirconium-containing metal oxide obtained above was concentrated using an ultrafiltration membrane, and an amount of methanol equal to the amount of the filtrate obtained was added to the concentrated dispersion obtained in this manner. Concentration of the dispersion and dilution with methanol were carried out continuously and simultaneously in parallel, thereby replacing the dispersion medium from water with methanol while maintaining the content of zirconium-containing metal oxide in the dispersion at 30 mass%, and thereby obtaining a methanol dispersion (B) of zirconium-containing metal oxide having a content of zirconium-containing metal oxide of 30 mass%.

[0075] (Production Example 3: Preparation of Aqueous Dispersion (C) of Zirconium-Containing Metal Oxide) 0.76 L of a 0.6 mol / L aqueous zirconium oxychloride solution and 0.53 L of a 1.9 mol / L aqueous sodium hydroxide solution were prepared. The zirconium oxychloride solution and the sodium hydroxide solution were simultaneously poured into a precipitation reactor containing 0.74 L of pure water, and the zirconium oxychloride was co-precipitated by simultaneous neutralization to obtain a slurry of zirconium oxide coprecipitate particles. The obtained slurry was filtered, washed, and repulped in pure water so that the solids content of the slurry was 5.6 mass% in terms of zirconium oxide, thereby obtaining 1 L of slurry. The electrical conductivity of this slurry was 235 μS / cm. 140.8 g of sodium citrate dihydrate (1 molar part per 1 molar part of zirconium in the slurry) was added to the slurry, and the mixture was hydrothermally treated at 200° C. for 3 hours to obtain a translucent dispersion. This translucent dispersion was washed and concentrated using an ultrafiltration membrane to obtain an aqueous dispersion (C) of zirconium-containing metal oxide having a zirconium-containing metal oxide content of 30% by mass.

[0076] (Production Example 4: Preparation of Zirconium-Containing Metal Oxide Aqueous Dispersion (D)) 90 L of a mixed aqueous solution of 0.6 mol / L zirconium oxychloride and 0.03 mol / L yttrium chloride and 68 L of a 1.9 mol / L sodium hydroxide aqueous solution were prepared. The mixed aqueous solution of zirconium oxychloride and yttrium chloride and the sodium hydroxide aqueous solution were simultaneously poured into a precipitation reactor containing 82 L of pure water, and the zirconium oxychloride and yttrium chloride were co-precipitated by simultaneous neutralization to obtain a first aqueous slurry of coprecipitate particles of zirconium oxide and yttrium. This first aqueous slurry was filtered, washed, and repulped in pure water so that the solid content was 11% by mass in terms of zirconium oxide and yttrium oxide, obtaining 60 L of a second aqueous slurry. The electrical conductivity of this second aqueous slurry was 70 μS / cm. A transparent aqueous dispersion was obtained by adding 4.2 kg of acetic acid (1.3 molar parts per 1 molar part of the total amount of zirconium and yttrium in the slurry) to the second aqueous slurry and subjecting it to hydrothermal treatment at 190° C. for 3 hours. This transparent dispersion was washed and concentrated using an ultrafiltration membrane to obtain an aqueous dispersion (D) of zirconium-containing metal oxide, which is a solid solution containing 4.8 mol % of yttrium and has a content of 30 mass % of zirconium-containing metal oxide.

[0077] (Production Example 5: Preparation of methanol dispersion (E) of zirconium-containing metal oxide) 10 kg of the aqueous dispersion (D) of zirconium-containing metal oxide obtained above was concentrated using an ultrafiltration membrane, and an amount of methanol equal to the amount of the filtrate obtained was added to the concentrated dispersion obtained in this manner. Concentration of the dispersion and dilution with methanol were carried out continuously and simultaneously in parallel, thereby replacing the dispersion medium from water with methanol while maintaining the content of zirconium-containing metal oxide in the dispersion at 30 mass%, and thereby obtaining a methanol dispersion (E) of zirconium-containing metal oxide having a content of zirconium-containing metal oxide of 30 mass%.

[0078] The pH of the aqueous dispersions or methanol dispersions of the zirconium-containing metal oxides obtained in Production Examples 1 to 5 and the particle sizes of the zirconium-containing metal oxides are shown in Table 1. In the case of the methanol dispersions, the pH shown is that of the aqueous dispersion before ultrafiltration.

[0079]

[0080] (Production Example 6: Preparation of hard coat liquid) 52.3 g of methanol and 16.0 g of dilute hydrochloric acid (0.1 N) were added dropwise to 69.7 g of γ-glycidoxypropyltrimethoxysilane, and hydrolysis was carried out over 48 hours. 45.3 g of propylene glycol monomethyl ether, 115.1 g of a methanol dispersion of zirconium-containing metal oxide (E), 1.40 g of tris(2,4-pentanedionato)aluminum(III) as a curing catalyst, and 0.11 g of a surfactant (manufactured by Neos Corporation, trade name "Ftergent 222F") were added, and the mixture was stirred for 24 hours to prepare a hard coat liquid.

[0081] Example 1 To 100.0 g of an aqueous dispersion (A) of zirconium-containing metal oxide having a zirconium-containing metal oxide concentration of 30 mass %, 220.21 g of water, 79.79 g of an aqueous polyurethane resin (manufactured by Nicca Chemical Co., Ltd., trade name "Evaphanol HA-170") having a nonvolatile content of 37.6 mass %, and 0.20 g of a leveling agent (manufactured by Dow-Toray Industries, Inc., trade name "L-7604") were added, and the mixture was stirred to obtain a primer layer-forming composition. The proportion of the zirconium-containing metal oxide in the solid content of the primer layer-forming composition was 50 mass %. (Formation of Primer Layer) Two types of commercially available plastic lens substrates (MR-8: manufactured by Mitsui Chemicals, Inc., substrate refractive index 1.60; MR-7: manufactured by Mitsui Chemicals, Inc., substrate refractive index 1.67) were prepared, and the primer layer-forming composition described in Example 1 (solid content concentration 15% by mass) was applied to each lens substrate by dipping at a speed of 130 mm / min. The lens substrate coated with the primer layer-forming composition was pre-cured by heating at 90°C for 10 minutes, and then fully cured by heating at 120°C for 2 hours, forming a primer layer with a thickness of 1 μm on the lens substrate. A primer layer with a thickness of 3 μm was also formed on a slide glass substrate using the same method as above.

[0082] (Formation of Primer Layer + Hard Coat Layer) Two types of commercially available plastic lens substrates (MR-8: manufactured by Mitsui Chemicals, Inc., substrate refractive index 1.60; MR-7: manufactured by Mitsui Chemicals, Inc., substrate refractive index 1.67) were prepared, and the primer layer-forming composition described in Example 1 (solid content concentration 15% by mass) was applied to each lens substrate by dipping at a speed of 130 mm / min. The lens substrate coated with the primer layer-forming composition was heated at 90°C for 10 minutes to pre-cure, and a primer layer with a thickness of 1 μm was formed on the lens substrate. The hard coat liquid described in Production Example 6 was applied to the lens substrate coated with the primer layer-forming composition by dipping at a speed of 130 mm / min. The lens substrate coated with the hard coat liquid was pre-cure by heating at 90°C for 10 minutes, and then heated at 120°C for 2 hours to fully cure, forming a hard coat layer with a thickness of 3 μm.

[0083] Example 2 A primer layer-forming composition was obtained using 100.0 g of a methanol dispersion (B) of zirconium-containing metal oxide with a zirconium-containing metal oxide concentration of 30 mass % in the same manner as in Example 1. The proportion of zirconium-containing metal oxide in the solid content of the primer layer-forming composition was 50 mass %. The primer layer and the primer layer + hard coat layer were formed using the same methods as in Example 1.

[0084] Example 3 To 100.0 g of an aqueous dispersion (A) of zirconium-containing metal oxide having a concentration of 30% by mass of zirconium-containing metal oxide, 220.21 g of water, 6.0 g of a surfactant (manufactured by BYK Japan K.K., trade name "DISPERBYK-180"), 79.79 g of an aqueous polyurethane resin (manufactured by NICCA Chemical Co., Ltd., trade name "EVAPHANOL HA-170") having a nonvolatile content of 37.6% by mass, and 0.20 g of a leveling agent (manufactured by Dow-Toray Industries, Inc., trade name "L-7604") were added, and the mixture was stirred to obtain a primer layer-forming composition. The proportion of zirconium-containing metal oxide in the solid content of the primer layer-forming composition was 45% by mass. The primer layer and the primer layer + hard coat layer were formed in the same manner as in Example 1.

[0085] Example 4 To 120.0 g of a methanol dispersion (B) of zirconium-containing metal oxide having a concentration of 30% by mass, 216.17 g of water, 63.83 g of an aqueous polyurethane resin (manufactured by Nicca Chemical Co., Ltd., trade name "Evaphanol HA-170") having a nonvolatile content of 37.6% by mass, and 0.20 g of a leveling agent (manufactured by Dow-Toray Industries, Inc., trade name "L-7604") were added, and the mixture was stirred to obtain a primer layer-forming composition. The proportion of zirconium-containing metal oxide in the solid content of the primer layer-forming composition was 60% by mass. The primer layer and the primer layer + hard coat layer were formed in the same manner as in Example 1.

[0086] Example 5 To 100.0 g of an aqueous dispersion (A) of zirconium-containing metal oxide having a concentration of 30% by mass of zirconium-containing metal oxide, 210.71 g of water, 89.29 g of an aqueous polyurethane resin (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name "Superflex 170") having a nonvolatile content of 33.6% by mass, and 0.20 g of a leveling agent (manufactured by Dow-Toray Industries, Inc., trade name "L-7604") were added, and the mixture was stirred to obtain a primer layer-forming composition. The proportion of zirconium-containing metal oxide in the solid content of the primer layer-forming composition was 50% by mass. The primer layer and the primer layer + hard coat layer were formed in the same manner as in Example 1.

[0087] Example 6 A primer layer-forming composition was obtained using 100.0 g of an aqueous dispersion (C) of zirconium-containing metal oxide with a zirconium-containing metal oxide concentration of 30 mass % in the same manner as in Example 1. The proportion of the zirconium-containing metal oxide in the solid content of the primer layer-forming composition was 50 mass %. The primer layer and the primer layer + hard coat layer were formed using the same methods as in Example 1.

[0088] Comparative Example 1 An attempt was made to prepare a primer layer-forming composition using 100.0 g of an aqueous dispersion (D) of zirconium-containing metal oxide having a concentration of 30 mass % of the zirconium-containing metal oxide in the same manner as in Example 1, but aggregates were generated and a primer layer-forming composition could not be prepared.

[0089] The results of evaluation of various physical properties for Examples 1 to 6 and Comparative Example 1 are shown in Table 2.

[0090]

[0091] From the results in Table 2, it was confirmed that by using a zirconium-containing metal oxide in which the silicon content is 20 mol % or less relative to 100 mol % of zirconium in (A), the average particle size is within a predetermined range, and the pH of a 30 mass % aqueous dispersion is 8 to 11, a composition capable of forming a primer layer having high transparency and a high refractive index can be obtained.

Claims

1. A primer layer-forming composition comprising a zirconium-containing metal oxide (A) and an aqueous urethane resin (B), wherein the zirconium-containing metal oxide (A) has an average particle size of 1 to 20 nm as measured by dynamic light scattering, a 30 mass % aqueous dispersion of the zirconium-containing metal oxide (A) has a pH of 8 to 11, and the silicon content is 20 mol % or less relative to 100 mol % of zirconium in (A).

2. A primer layer-forming composition according to claim 1, wherein the content of the zirconium-containing metal oxide (A) is 40 to 80 mass % relative to 100 mass % of the solid content in the primer layer-forming composition.

3. A primer layer-forming composition according to claim 1, wherein the content of solids in the aqueous urethane resin (B) is 20 to 60 mass% relative to 100 mass% of the solids in the primer layer-forming composition.

4. The composition for forming a primer layer according to any one of claims 1 to 3, which is used for lenses.

5. A lens coated with the composition for forming a primer layer according to any one of claims 1 to 3.

6. A method for producing a composition for forming a primer layer, comprising the step of mixing a zirconium-containing metal oxide (A) with an aqueous urethane resin (B), wherein the zirconium-containing metal oxide (A) has an average particle size of 1 to 20 nm as measured by dynamic light scattering, and a pH of 8 to 11 when dispersed in 30% by mass in water.

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