Eyeglass lenses

Abstract

This invention provides an eyeglass lens with excellent anti-fog properties, light resistance, and minimal color change. The eyeglass lens has a substrate and an absorbent anti-fog layer disposed on the substrate as the outermost layer. The absorbent anti-fog layer contains an ultraviolet absorber and has the following spectral characteristics: light transmittance of at least 5% in the 350-370 nm range; and light transmittance of 5% or more at wavelengths above 370 nm.

Description

Technical Field

[0001] This invention relates to spectacle lenses. Background Technology

[0002] To prevent eyeglass lenses from fogging, an anti-fog layer has been proposed to be provided on the lens substrate. For example, Patent Document 1 describes the provision of an anti-fog layer consisting of a water-absorbing layer on eyeglass lenses.

[0003] On the other hand, considering that eyeglass lenses are used for extended periods in various environments, a highly durable anti-fog layer is required that eliminates the hassle of periodically reforming the anti-fog layer. Therefore, it is considered to combine water-absorbing and slip-enhancing components in the anti-fog layer to make it both absorbent and waterproof, while also providing scratch resistance and low frictional resistance.

[0004] When such a function is given to the anti-fog layer, the durability of the anti-fog layer increases, resulting in a requirement for lightfastness as well. Therefore, it is considered to suppress the light degradation of the anti-fog layer by incorporating an ultraviolet absorber into it. In addition, Patent Document 1 describes that, in cases where there is concern about substrate degradation, it is preferable to include an ultraviolet absorber in the absorbent layer.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent document 1: International Publication No. 2013 / 005710. Summary of the Invention

[0008] The problem the invention aims to solve

[0009] However, in the case of eyeglass lenses with anti-fog layers that improve durability as described above, it has been found that if only ultraviolet absorbers are used, there is a problem of changes in luminous transmittance and hue over time due to light exposure. This problem is more pronounced when the lens substrate is stained with a non-color such as gray.

[0010] In view of the above-mentioned problems, the present invention aims to provide eyeglass lenses with excellent anti-fog properties, light resistance, and minimal color change.

[0011] Solution for solving the problem

[0012] In order to solve the above problems, the inventors conducted repeated and in-depth research and found that by including an ultraviolet absorber with specific properties in the water-absorbing anti-fog layer, the above problems can be solved, thus completing the present invention.

[0013] That is, the present invention provides the following [1] to [7].

[0014] [1] A spectacle lens having a substrate and an absorbent anti-fog layer disposed on the substrate as the outermost layer.

[0015] The aforementioned water-absorbing anti-fog layer contains ultraviolet absorbers.

[0016] The above-mentioned water-absorbing anti-fog layer has the following spectral characteristics: light transmittance of at least 5% in the 350-370nm range; and light transmittance of 5% or more at wavelengths above 370nm.

[0017] [2] According to the eyeglass lens described in [1] above, the water-absorbing anti-fog layer is composed of a cured film of a coating composition comprising the following components (A) to (C).

[0018] Component (A): A (meth)acrylic resin (A) having structural units derived from monomers (a-1) represented by general formula (1), structural units derived from monomers (a-2) represented by general formula (2), structural units derived from hydroxyalkyl (meth)acrylate (a-3), and structural units derived from monomers (a-4) represented by general formula (3).

[0019] Component (B): Polyol compound (B),

[0020] Component (C): Polyfunctional isocyanate compound (C).

[0021] [Chemical Formula 1]

[0022]

[0023] [In general formula (1), R1 is a hydrogen atom or a methyl group, and R2 and R3 are each independently a hydrogen atom or a straight-chain or branched alkyl group having 1 to 3 carbon atoms.]

[0024] [Chemical Formula 2]

[0025]

[0026] [In general formula (2), R4 is a hydrogen atom or a methyl group, and m is an integer from 1 to 5.]

[0027] [Chemical Formula 3]

[0028]

[0029] [In general formula (3), R5 is a hydrogen atom or a methyl group, R6 is a divalent organic group, and n is an integer of 0 or 1.]

[0030] [3] The spectacle lens according to [1] or [2] above, wherein the ultraviolet absorber comprises a compound represented by the following general formula (4).

[0031] [Chemical Formula 4]

[0032]

[0033] [In equation (4), n1 is 2 or 3.]

[0034] [4] The spectacle lens according to [1] or [2] above, wherein the ultraviolet absorber comprises a compound represented by the following general formula (5).

[0035] [Chemical Formula 5]

[0036]

[0037] [In equation (5), n2 is 2 or 3, and n3 is 2 or 3.]

[0038] [5] The spectacle lens according to any one of [1] to [4] above, wherein the substrate is dyed with a colorant.

[0039] [6] The eyeglass lens according to [5] above, wherein the substrate is dyed gray.

[0040] [7] The spectacle lens according to any one of [1] to [6], wherein the substrate is made of resin.

[0041] Invention Effects

[0042] According to the present invention, it is possible to provide spectacle lenses with excellent anti-fog properties, light resistance, and minimal color change. Attached Figure Description

[0043] Figure 1 These are a cross-sectional schematic diagram and a partial enlarged view of the spectacle lens 10. Detailed Implementation

[0044] The following describes embodiments and examples of the present invention. Identical or equivalent parts are labeled with the same reference numerals in the accompanying drawings, and their descriptions are sometimes omitted. In the embodiments and examples described below, when referring to numbers, quantities, etc., the scope of the present invention is not necessarily limited to those numbers, quantities, etc., unless specifically stated otherwise. In the embodiments described below, unless specifically stated otherwise, each constituent element is not necessarily essential to the embodiments and examples of the present invention.

[0045] In the description of groups (atomic groups) in this specification, the description of "unsubstituted" or "unsubstituted" includes both groups without substituents and groups with substituents. For example, "alkyl" includes alkyl groups without substituents (unsubstituted alkyl) and alkyl groups with substituents (substituted alkyl).

[0046] The term "(meth)acrylic acid" in this specification indicates that it includes both acrylic acid and methacrylic acid. The same applies to terms such as "(meth)acrylate".

[0047] In this specification, structural units from monomer (a-1) are sometimes referred to as "structural unit (a-1)", structural units from monomer (a-2) are referred to as "structural unit (a-2)", structural units from monomer (a-3) are referred to as "structural unit (a-3)", and structural units from monomer (a-4) are referred to as "structural unit (a-4)".

[0048] [Eyeglass lenses]

[0049] The spectacle lens of the present invention has a substrate and a water-absorbing anti-fog layer disposed on the substrate as the outermost layer. The water-absorbing anti-fog layer contains an ultraviolet absorber. In addition, the water-absorbing anti-fog layer has the following spectral characteristics: the light transmittance at least in the range of 350 to 370 nm is less than 5%; and the wavelength with a light transmittance of 5% or more is 370 nm or more.

[0050] Figure 1 This is a cross-sectional schematic diagram and a partial enlarged view of spectacle lens 10, which is an example of a spectacle lens. (Refer to...) Figure 1 The structure of the spectacle lens 10 is described below. The spectacle lens 10 has a lens body. The lens body is composed of a lens substrate 11, which will be described later.

[0051] like Figure 1 As shown, the spectacle lens 10 has a spectacle lens substrate 11 (hereinafter also simply referred to as "lens substrate") that serves as the substrate constituting the main body of the lens. The lens substrate 11 has a first main surface 111, a second main surface 112, and an edge surface 113. A water-absorbing anti-fog layer 20 is provided on the first main surface 111 of the lens substrate 11. A water-absorbing anti-fog layer 21 is also provided on the second main surface 112 of the lens substrate 11.

[0052] The water-absorbing anti-fog layers 20 and 21 are the outermost layers of the eyeglass lens 10, and are exposed to the external space.

[0053] like Figure 1 As shown in the enlarged view, a dyed layer 11a is formed near the first main surface 111 and a dyed layer 11b is formed near the second main surface 112.

[0054] The dyeing layers 11a and 11b are layers dyed with a specified dye. By giving the lens substrate the aforementioned dyeing layers, eyeglass lenses can be colored in any color (e.g., gray).

[0055] The water-absorbing anti-fog layer can be applied to only one main surface. For example, it can be applied only to one surface. Figure 1 The method of providing a water-absorbing anti-fog layer 20 on the first main surface 111 can also be that only one is provided. Figure 1 The water-absorbing anti-fog layer 21 is applied to the second main surface 112.

[0056] Alternatively, the dye can be premixed with the colorant in the raw materials used to form the lens substrate, allowing the dye to be dispersed throughout the lens substrate.

[0057] Eyeglass lenses, through the presence of a cured coating with both water-absorbing and water-repellent properties, such as the coating composition described later, are endowed not only with excellent anti-fogging properties but also with scratch resistance and low frictional resistance. Furthermore, by incorporating a UV absorber with specific properties into the aforementioned anti-fogging layer, the anti-fogging layer exhibits excellent lightfastness, and even with prolonged use, the color of the eyeglass lenses changes minimally. Therefore, even if the lens substrate is stained, particularly a non-color such as gray, the color is not easily altered.

[0058] <Lens Substrate>

[0059] The lens substrate is, for example, an eyeglass lens substrate. The lens substrate is preferably made of resin. The lens substrate can be a lens substrate dyed with a colorant as described above, or it can be a lens substrate dyed, for example, gray.

[0060] Examples of resins used to form lens substrates include polycarbonate resins, polyurethane urea resins, allyl acrylate resins, (thio)polyurethane resins, polysulfide resins, polyamide resins, and polyester resins. (Thio)polyurethane resins refer to at least one selected from thio polyurethane resins and polyurethane resins. Among these, (thio)polyurethane resins, polycarbonate resins, and polysulfide resins are preferred.

[0061] Furthermore, the lens substrate used in the spectacle lens of this embodiment is preferably a plastic lens substrate with a refractive index of 1.50 or higher, and more preferably a refractive index of 1.60 or higher.

[0062] Commercially available products that are preferred plastic lens substrates include allyl polycarbonate-based plastic lenses such as "HILUX1.50" (manufactured by Hoya Corporation, refractive index 1.50), thiopolyurethane-based plastic lenses such as "MERIA" (manufactured by Hoya Corporation, refractive index 1.60), thiopolyurethane-based plastic lenses such as "EYAS" (manufactured by Hoya Corporation, refractive index 1.60), thiopolyurethane-based plastic lenses such as "EYNOA" (manufactured by Hoya Corporation, refractive index 1.67), polysulfide-based plastic lenses such as "EYRY" (manufactured by Hoya Corporation, refractive index 1.70), and polysulfide-based plastic lenses such as "EYVIA" (manufactured by Hoya Corporation, refractive index 1.74).

[0063] (Coloring agent)

[0064] Colorants used for dyeing lens substrates can be added to solutions used for dyeing lens substrates.

[0065] Examples of colorants used to dye substrates include disperse dyes, oil-soluble dyes, and other dyes and pigments. These dyes and pigments can be used alone or in combination of two or more.

[0066] When the substrate is colored gray, the human eye can easily perceive the color change caused by yellowing. Therefore, the yellowing suppression effect brought about by the aforementioned water-absorbing anti-fog layer is significant. Examples of dyes that color the substrate gray include azo-based disperse dyes and anthraquinone-based disperse dyes.

[0067] <Substrate dimensions, optical properties, etc.>

[0068] There are no particular limitations on the thickness and diameter of the substrate. The thickness is usually around 1 to 30 mm, and the diameter is usually around 50 to 100 mm.

[0069] The refractive index ne of the substrate is preferably 1.50 or higher, more preferably 1.53 or higher, even more preferably 1.55 or higher, even more preferably 1.58 or higher, even more preferably 1.60 or higher, particularly preferably 1.67 or higher, preferably 1.80 or lower, and more preferably 1.70 or lower.

[0070] As a lens substrate, it can be either a finished lens or a semi-finished lens.

[0071] There are no particular restrictions on the surface shape of the lens substrate; it can be any of the following: flat, convex, concave, etc.

[0072] The spectacle lens of the present invention can be any of a single-focal lens, a multifocal lens, or a progressive lens. In a progressive lens, the lower region typically includes a near-use region (near-use portion) and a progressive region (intermediate region), and the upper region includes a distance-use region (distance-use portion).

[0073] <Water-absorbing anti-fog layer>

[0074] The water-absorbing anti-fog layer is located on the outermost layer of the eyeglass lens and has the following spectral characteristics: light transmittance of less than 5% at least in the 350-370nm range; and light transmittance of more than 5% at wavelengths above 370nm.

[0075] By placing the water-absorbing anti-fog layer on the outermost layer of the eyeglass lens, fogging due to moisture present in the external environment can be prevented. Furthermore, by giving the water-absorbing anti-fog layer the aforementioned spectral characteristics, ultraviolet rays contained in light directed towards the eyeglass lens from the outside can be suppressed from entering the lens substrate. This prevents yellowing of the water-absorbing anti-fog layer and inhibits fading of dyes applied to the lens substrate during prolonged exposure to ultraviolet light.

[0076] The water-absorbing anti-fog layer has the following spectral transmittance: at least less than 5% light transmittance in the 350-370 nm range; the wavelength with a light transmittance of 5% or more is preferably 375 nm or more, more preferably 380 nm or more, even more preferably 382 nm or more, and preferably 420 nm or less, more preferably 400 nm or less.

[0077] The transmittance of the water-absorbing anti-fog layer at wavelengths less than 350nm is preferably less than 1%.

[0078] A water-absorbing anti-fog layer is a layer that is water-absorbing. Here, water absorption refers to the property of a material to absorb moisture. It means that when a transparent substrate with the above-mentioned anti-fog layer is stored at room temperature, and the transparent substrate with the anti-fog layer is placed at a distance of 35 mm from the surface of warm water at 40°C and exposed to steam from the warm water for 15 seconds, there is no diffuse reflection on the surface of the anti-fog layer caused by fine water droplets, and the image observed through the transparent substrate with the anti-fog layer after contact with the steam is not distorted by condensation.

[0079] The absorbent anti-fog layer preferably has waterproof properties. This further improves the anti-fog performance.

[0080] The aforementioned water-absorbing anti-fog layer is a single layer made of a water-absorbing resin material, preferably a single layer with a water contact angle of 85° to 120°.

[0081] When a water-absorbing anti-fog layer has the above-mentioned characteristics, it not only has water absorption properties, but also easily imparts properties such as scratch resistance, low frictional resistance, and solvent resistance. Even if the water-absorbing anti-fog layer is located on the outermost layer of the eyeglass lens, it will still exhibit high durability.

[0082] The contact angle of the anti-fog layer with water is expressed by the following angle: at 20°C, a drop of 20 μl of pure water is brought into contact with the surface of the flat anti-fog layer, which is the test object, and allowed to drip. The angle between the water droplet and the surface of the anti-fog layer is measured 30 seconds after the drop begins to fall.

[0083] (Thickness of the water-absorbing anti-fog layer)

[0084] From the viewpoint of ease of manufacture, the thickness of the water-absorbing anti-fog layer is preferably 1 to 100 μm, more preferably 3 to 60 μm, even more preferably 6 to 50 μm, even more preferably 8 to 40 μm, and even more preferably 12 to 30 μm.

[0085] From the viewpoint of improving anti-fogging properties, the thickness of the above-mentioned water-absorbing anti-fogging layer is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 6 μm or more, even more preferably 8 μm or more, even more preferably 12 μm or more. From the viewpoint of ease of manufacture, it is preferably 100 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less, even more preferably 40 μm or less, even more preferably 30 μm or less.

[0086] (Application Composition)

[0087] The water-absorbing anti-fog layer is preferably a cured film comprising a coating composition containing structural units from siloxane compounds and structural units from acrylamide.

[0088] By incorporating structural units derived from siloxane compounds, the slipping property of the water-absorbing antifog layer is improved, resulting in enhanced scratch resistance. Furthermore, the presence of amide groups derived from acrylamide increases the hydrophilicity of the water-absorbing antifog layer, thereby improving its water absorption and consequently its antifog properties.

[0089] The aforementioned water-absorbing anti-fog layer is preferably composed of a cured film of a coating composition comprising the following components (A) to (C).

[0090] Component (A): A (meth)acrylic resin having structural units derived from monomers (a-1) represented by general formula (1), structural units derived from monomers (a-2) represented by general formula (2), structural units derived from hydroxyalkyl (meth)acrylate (a-3), and structural units derived from monomers (a-4) represented by general formula (3).

[0091] Component (B): Polyol compound (B),

[0092] Component (C): Polyfunctional isocyanate compound (C).

[0093] [Chemical Formula 6]

[0094]

[0095] [In general formula (1), R1 is a hydrogen atom or a methyl group, and R2 and R3 are each independently a hydrogen atom or a straight-chain or branched alkyl group having 1 to 3 carbon atoms.]

[0096] [Chemical Formula 7]

[0097]

[0098] [In general formula (2), R4 is a hydrogen atom or a methyl group, and m is an integer from 1 to 5.]

[0099] [Chemical Formula 8]

[0100]

[0101] [In general formula (3), R5 is a hydrogen atom or a methyl group, R6 is a divalent organic group, and n is an integer of 0 or 1.]

[0102] The structural unit (a-1) of resin (A) (also known as (meth)acrylic resin) contains an amide group, which is highly hydrophilic and easily retains moisture. Therefore, it is believed that moisture adhering to the surface of the water-absorbing anti-fog layer obtained by curing the coating composition is easily absorbed into the cured interior. Furthermore, it is believed that by incorporating polyol compound (B), the crosslinking density required for a water-absorbing anti-fog layer can be maintained, and gaps sufficient for moisture absorption can be maintained. Based on these reasons, it is believed that the cured film of the above-mentioned coating composition possesses anti-fog properties.

[0103] Furthermore, the structural unit (a-2) contained in resin (A) is a polycaprolactone structure, which contributes to the softness and elasticity of the water-absorbing anti-fog layer through its soft chemical backbone. In addition, the inclusion of a more rigid structural unit (a-3) than structural unit (a-2) ensures a balance between softness and elasticity. On the other hand, the polydimethylsiloxane chain in structural unit (a-4) helps improve the sliding properties of the water-absorbing anti-fog layer. Therefore, it is believed that when an external force is applied to the water-absorbing anti-fog layer, the two effects—absorbing the external force through the softness and elasticity of the water-absorbing anti-fog layer and releasing the external force outside the water-absorbing anti-fog layer through sliding properties—are synergistically manifested, resulting in less damage to the water-absorbing anti-fog layer.

[0104] In the coating composition, relative to all structural units of 100% by mass of constituent component (A), the proportion of structural units from monomer (a-1) is 20% by mass or more and 65% by mass or less, the proportion of structural units from monomer (a-2) is 10% by mass or more and 40% by mass or less, the proportion of structural units from monomer (a-4) is 1% by mass or more and 10% by mass or less, and the ratio (NCO) of the number of isocyanate groups (NCO) contained in component (C) to the total number of hydroxyl groups (OH) contained in component (A) and component (B) is preferably 0.15 or more and 0.55 or less.

[0105] It is believed that when the composition of the coating composition is set in this way, the hydroxyl-containing structural units (a-2) and (a-3) in component (A) are balanced (in terms of quantity ratio), and the equivalent ratio (NCO / OH) is set within a specific range of less than 1, which can increase the hardness of the water-absorbing antifogging layer to the extent that the frictional resistance is increased. Furthermore, it is believed that by achieving structural balance between the hydroxyl-containing structural units (a-2) and (a-3) in component (A) and setting the equivalent ratio (NCO / OH) within a specific range of less than 1, the crosslinking density of the water-absorbing antifogging layer increases, thereby improving the solvent resistance of the water-absorbing antifogging layer.

[0106] The following describes the components contained in the coating composition of this embodiment.

[0107] (Component (A): (Meth)acrylic resin)

[0108] The coating composition of this embodiment preferably includes a (meth)acrylic resin as component (A), that is, preferably a (meth)acrylic resin having structural units from monomers (a-1) represented by general formula (1), structural units from monomers (a-2) represented by general formula (2), structural units from hydroxyalkyl methacrylates (a-3), and structural units from monomers (a-4) represented by general formula (3).

[0109] As mentioned above, the structural unit (a-1) is considered to be mainly related to the absorption of water (moisture).

[0110] (Meth)acrylic resins are typically obtained by polymerizing monomers (a-1), (a-2), (a-3), and (a-4). Details of the polymerization methods are described later.

[0111] Furthermore, in this embodiment, the structural units constituting the (meth)acrylic resin may not be 100% derived from (meth)acrylic monomers. That is, the (meth)acrylic resin may contain structural units that are partly (but not entirely) derived from non-(meth)acrylic monomers.

[0112] To fully realize the benefits of the (meth)acrylic acid structure, it is preferable that at least 50% by mass of all structural units in the (meth)acrylic acid resin are structural units derived from (meth)acrylic acid monomers. More preferably, at least 80% by mass of all structural units in the (meth)acrylic acid resin are structural units derived from (meth)acrylic acid monomers. Even more preferably, all (100%) structural units of the (meth)acrylic acid resin are structural units derived from (meth)acrylic acid monomers.

[0113] The monomer (a-1) is not particularly limited as long as it has the structure of the general formula (1) described above. Specifically, examples include (meth)acrylamide, N-methacrylamide, N,N-dimethyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-n-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, etc.

[0114] Monomer (a-1) can be at least one type, or two or more types can be used in combination. For example, (meth)acrylic resins can be obtained by using two or more of the monomers listed above in a polymerization reaction.

[0115] From the viewpoint of improving anti-fogging performance, monomer (a-1) is particularly preferably composed of N,N-dimethyl (meth)acrylamide and N,N-diethyl (meth)acrylamide.

[0116] In this embodiment, the structural unit derived from monomer (a-1) in the (meth)acrylic resin preferably comprises 20 to 65% by mass relative to all structural units of the resin. More preferably, it comprises 35 to 60% by mass, and even more preferably, it comprises 40 to 55% by mass. If the structural unit derived from monomer (a-1) is 20% by mass or more, it is easy to form a water-absorbing anti-fogging layer that exhibits practical anti-fogging properties. If the structural unit derived from monomer (a-1) is 65% by mass or less, the reduction in the proportion of structural units derived from other monomers is relatively avoided, and it is easy to maintain the balance of the composition as a whole.

[0117] There are no particular limitations on the monomer (a-2) as long as it has the structure of the general formula (2) above.

[0118] In this embodiment, the (meth)acrylic resin comprises, with respect to all structural units of the resin, preferably 10-40% by mass, more preferably 20-38% by mass, and even more preferably 25-35% by mass of structural units derived from monomer (a-2).

[0119] If the structural units from monomer (a-2) account for more than 10% by mass, it is easy to ensure the softness of the water-absorbing anti-fog layer; if the structural units from monomer (a-2) account for less than 40% by mass, it is easy to ensure the elasticity of the water-absorbing anti-fog layer.

[0120] (Meth)acrylic resins can contain multiple repeating units derived from monomer (a-2).

[0121] The monomer (a-3) is a hydroxyalkyl methacrylate. Specific examples include hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. In this embodiment, hydroxyethyl methacrylate is preferred among these.

[0122] In this embodiment, the structural unit derived from monomer (a-3) in the (meth)acrylic resin preferably comprises 1 to 30% by mass relative to all structural units of the (meth)acrylic resin, more preferably 2 to 20% by mass, and even more preferably 3 to 15% by mass.

[0123] In addition, monomers (a-3) and (a-2) also have hydroxyl groups, which can undergo cross-linking reactions with the polyfunctional isocyanate compounds described later to form a water-absorbing anti-fog layer.

[0124] In this embodiment, instead of forming a water-absorbing anti-fog layer solely through a cross-linking reaction of monomer (a-2), a cross-linking reaction is formed together with monomer (a-3) and a polyfunctional isocyanate compound, thereby forming a water-absorbing anti-fog layer with various physical properties.

[0125] As described above, (meth)acrylic resins contain structural units derived from monomers (a-2) and (a-3), and are therefore resins that possess hydroxyl groups as a whole, i.e., have hydroxyl values. Therefore, they can react with the polyol compounds described later and the polyfunctional isocyanate compounds described later to form a cross-linked structure.

[0126] The hydroxyl value of the (meth)acrylic resin is preferably 40-150 mgKOH / g, more preferably 70-140 mgKOH / g, and even more preferably 90-130 mgKOH / g.

[0127] By setting the hydroxyl value of the (meth)acrylic resin to this range, and reacting it together with a polyol compound (described later) and a polyfunctional isocyanate compound (described later), the crosslinking structure can be easily and appropriately controlled. Therefore, it is possible to maintain the softness and elasticity of the absorbent antifog layer while simultaneously hardening it. Consequently, it is easy to achieve a higher balance between scratch resistance, reduced frictional resistance, and solvent resistance in the absorbent antifog layer.

[0128] In addition, the hydroxyl value refers to the number of milligrams (mg) of potassium hydroxide required to neutralize the acetic acid bonded to the hydroxyl group when acetylated 1g of sample.

[0129] There are no particular limitations on the monomer (a-4) as long as it has the structure of the general formula (3) mentioned above.

[0130] (Meth)acrylic resins can contain multiple repeating units derived from monomers (a-4). For example, (meth)acrylic resins can be obtained by polymerization using two or more of the monomers listed above.

[0131] In this embodiment, the structural unit derived from monomer (a-4) in the (meth)acrylic resin preferably comprises 1 to 10% by mass relative to all structural units of the resin, more preferably 2 to 8% by mass, and even more preferably 3 to 7% by mass.

[0132] If the structural units derived from monomer (a-4) are 1% or more by mass, a water-absorbing antifog layer with satisfactory scratch resistance can be easily obtained. If the structural units derived from monomer (a-4) are less than 10% by mass, a homogeneous resin (A) can be easily synthesized.

[0133] (Meth)acrylic resins may or may not contain any structural unit other than structural unit (a-1), structural unit (a-2), structural unit (a-3), and structural unit (a-4) (structural unit (a-5)). Examples of structural units (a-5) include those derived from the monomers shown below. By including such structural units in the (meth)acrylic resin, the glass transition temperature of the (meth)acrylic resin and the physical properties of the water-absorbing antifogging layer (hardness, softness, etc.) can be adjusted and optimized.

[0134] As structural units (a-5), examples can be derived from the following monomers: in the general formula CH2=CR-COO-R', R is a hydrogen atom or a methyl group, and R' is an alkyl group, a monocyclic or polycyclic cycloalkyl group, an aryl group, or an aralkyl group.

[0135] Specific examples of this monomer include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, isodecanyl methacrylate, lauryl methacrylate, stearyl methacrylate, phenyl methacrylate, and benzyl methacrylate.

[0136] Among these, it is preferred that R' is an alkyl monomer having 1 to 8 carbon atoms, more preferably that R' is an alkyl monomer having 1 to 6 carbon atoms, and even more preferably that R' is an alkyl monomer having 1 to 4 carbon atoms.

[0137] (Meth)acrylic resins can contain multiple repeating units belonging to structural unit (a-5). For example, (meth)acrylic resins can be obtained by polymerization using two or more of the monomers mentioned above as specific examples.

[0138] When the (meth)acrylic resin contains structural unit (a-5), its content relative to all structural units of the (meth)acrylic resin is preferably 1 to 40% by mass, more preferably 3 to 30% by mass, and even more preferably 5 to 20% by mass.

[0139] The mass-average molecular weight (Mw) of the (meth)acrylic resin is not particularly limited, but is preferably 10,000 to 100,000, more preferably 20,000 to 70,000, and even more preferably 30,000 to 60,000. If the mass-average molecular weight of the (meth)acrylic resin is 10,000 or more, the desired anti-fogging performance is easily obtained; if the mass-average molecular weight of the (meth)acrylic resin is 100,000 or less, the coating adaptability is excellent when applied to objects such as eyeglass lenses.

[0140] In addition, the mass-average molecular weight can be determined by gel permeation chromatography (GPC) using polystyrene as a standard.

[0141] The glass transition temperature of (meth)acrylic resins is not particularly limited, but is preferably 20 to 120°C, more preferably 30 to 110°C, and even more preferably 35 to 100°C.

[0142] In addition, the glass transition temperature of (meth)acrylic resins can be determined by various methods, such as based on the following Fox equation.

[0143] 1 / Tg=(W1 / Tg1)+(W2 / Tg2)+(W3 / Tg3)+…+(W n / Tg n )

[0144] [In the formula, Tg represents the glass transition temperature (K) of the (meth)acrylic resin, W1, W2, W3...W n The Tg1, Tg2, Tg3...Tg represent the mass fraction of each monomer. n These represent the glass transition temperatures (K) of the homopolymers composed of monomers corresponding to their respective mass fractions.

[0145] In this specification, the glass transition temperature of (meth)acrylic resins (not the glass transition temperature of the water-absorbing antifogging layer, but the glass transition temperature of the (meth)acrylic resin alone) refers to the glass transition temperature calculated based on the above formula. Furthermore, for monomers with uncertain glass transition temperatures, such as special monomers and multifunctional monomers, only monomers with known glass transition temperatures are used to calculate the glass transition temperature.

[0146] (Meth)acrylic resins can typically be obtained through polymerization reactions. Various methods, such as free radical polymerization, cationic polymerization, and anionic polymerization, are acceptable for the polymerization reaction, with free radical polymerization being particularly preferred. Furthermore, the polymerization can be any of solution polymerization, suspension polymerization, and emulsion polymerization. From the viewpoint of precise control over the polymerization process, solution polymerization is preferred.

[0147] As polymerization initiators for free radical polymerization, well-known polymerization initiators can be used. Examples include: azo-based initiators such as azobisisobutyronitrile, 2,2-azobis(2-methylbutyronitrile), 2,2-azobis(2-methylpropionitrile), and 2,2-azobis(2,4-dimethylpentanonitrile); peroxide-based initiators such as benzoyl peroxide, tert-butyl peroxyoctanoate, diisobutyl peroxide, di(2-ethylhexyl) peroxypentanoate, decanoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, and tert-butyl peroxybenzoate; and redox initiators that combine oxidizing and reducing agents, such as hydrogen peroxide and ferrous(II) salts, persulfates and sodium bisulfite. These can be used individually or in combination with two or more.

[0148] There is no particular limitation on the amount of polymerization initiator. When the total amount of the monomer mixture is taken as 100 parts by mass, it is preferred to set it to 0.001 to 10 parts by mass.

[0149] Furthermore, known chain transfer agents, polymerization inhibitors, molecular weight regulators, etc., can be appropriately used during the polymerization reaction. Moreover, the polymerization reaction can be carried out in one stage or in two or more stages. The temperature of the polymerization reaction is not particularly limited, typically ranging from 50°C to 200°C, preferably from 80°C to 150°C.

[0150] (Ingredient (B): Polyol compound)

[0151] The coating composition of this embodiment preferably contains a polyol compound. By containing a polyol compound, the coating composition of this embodiment can react with a (meth)acrylic resin and the polyfunctional isocyanate compound described later to form a water-absorbing antifogging layer with superior antifogging durability. The polyol compound has 2 or more hydroxyl groups per molecule, preferably 2 to 6, and more preferably 2 to 4.

[0152] The polyol compound preferably includes at least one polyol compound selected from polycaprolactone polyol, polycarbonate polyol, and polyether polyol. These polyol compounds have a moderately soft and elastic chemical structure. Therefore, the softness and elasticity of the absorbent antifog layer can be further improved.

[0153] Polycaprolactone polyols can be used without particular restrictions as long as they are compounds that have an open ring structure of caprolactone and two or more hydroxyl groups in one molecule.

[0154] Polycarbonate polyols can be used without particular restrictions as long as they are compounds containing a carbonate group represented by -O-(C=O)-O- and two or more hydroxyl groups in one molecule. Polycarbonate polyols can be obtained by reacting one or more polyol raw materials (polyols) with carbonates and phosgene.

[0155] There are no particular limitations on the polyol raw materials used, and examples include aliphatic polyols, polyols with alicyclic structures, and aromatic polyols. In this embodiment, from the viewpoint of the flexibility of the cured film, aliphatic polyols without alicyclic structures are preferred.

[0156] Examples of carbonates include aliphatic carbonates such as dimethyl carbonate and diethyl carbonate; aromatic carbonates such as diphenyl carbonate; and cyclic carbonates such as ethylene carbonate. Among these, aliphatic carbonates are preferred from the viewpoint of ease of obtaining and manufacturing, and dimethyl carbonate is particularly preferred.

[0157] Polyether polyols can be used without particular restrictions as long as they are compounds that have an ether bond (-O-) and two or more hydroxyl groups in one molecule.

[0158] Specific compounds that can be cited include: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dihydroxymethylheptane, diethylene glycol, dipropylene glycol, neopentanediol, cyclohexane-1,4-diol, cyclohexane-1,4-diethanol, dimerized acid glycol, bisphenol A, bis(β-hydroxyethyl)benzene, benzyl alcohol, glycerol, triglycerides, etc. Polyether polyols obtained by addition polymerization of ethylene oxide, propylene oxide, ethylene oxide, butane, etc., using low-molecular-weight polyols such as hydroxymethylpropane and pentaerythritol; or by using low-molecular-weight polyamines such as ethylenediamine, propylenediamine, toluenediamine, m-phenylenediamine, diphenylmethanediamine, and phenylenediamine, etc., with compounds having two or more, preferably two to three active hydrogens, as initiators; or polyether polyols obtained by ring-opening polymerization of alkyl glycidyl ethers such as methyl glycidyl ether, aryl glycidyl ethers such as phenyl glycidyl ether, tetrahydrofuran, etc.

[0159] In addition, in this embodiment, the polyol compound may be a variety of compounds belonging to polycaprolactone polyols, polycarbonate polyols, and polyether polyols. For example, the polyol compound may be a polyether polyester polyol having ether bonds and ester bonds.

[0160] In addition, polyol compounds may also include a variety of polycaprolactone polyols, polycarbonate polyols, and polyether polyols.

[0161] The hydroxyl value of the polyol compound is preferably 50 to 500 mg KOH / g, more preferably 100 to 350 mg KOH / g, and even more preferably 150 to 250 mg KOH / g. By ensuring that the hydroxyl content of the polyol compound is appropriate, the cross-linking structure formed by the reaction with the polyfunctional isocyanate compound described below can be controlled, which easily further improves the softness and elasticity of the water-absorbing antifog layer.

[0162] In this embodiment, the mass-average molecular weight (Mw) of the polyol compound is preferably 450 to 2500, more preferably 500 to 1500, and even more preferably 500 to 700. By making the mass-average molecular weight of the polyol compound an appropriate molecular weight, it is easier to achieve a higher degree of balance between suppressing the appearance changes of the water-absorbing anti-fog layer based on improved softness and elasticity and the durability of the water-absorbing anti-fog layer such as gasoline resistance.

[0163] The content of the polyol compound in the coating composition is preferably 5 to 200 parts by weight relative to 100 parts by weight of (meth)acrylic resin, more preferably 15 to 180 parts by weight, further preferably 20 to 150 parts by weight, even more preferably 20 to 100 parts by weight, even more preferably 20 to 50 parts by weight, and even more preferably 20 to 40 parts by weight. By setting the content of the polyol compound in the coating composition within this range, it is easy to obtain the properties derived from the polyol compound and to easily achieve a balance with other components.

[0164] In this embodiment, as a polyol compound, polycaprolactone polyol is preferably included among the above-mentioned polycaprolactone polyol, polycarbonate polyol and polyether polyol, and polycaprolactone diol (a compound having a caprolactone structure and having two hydroxyl groups) is particularly preferred among polycaprolactone polyol.

[0165] This is because the (meth)acrylic resin, which is component (A), has the structure of the above general formula (2), namely the caprolactone structure. Therefore, using the above compound as a polyol compound will easily improve the compatibility with the resin, and will not excessively increase the crosslinking density and will easily improve the antifogging performance.

[0166] (Component (C): Polyfunctional isocyanate compound)

[0167] The coating composition of this embodiment preferably includes a polyfunctional isocyanate compound as component (C). The coating composition forms a water-absorbing antifog layer with excellent antifog durability by crosslinking the polyfunctional isocyanate compound with the hydroxyl groups of the structural units (a-2) and (a-3) of the (meth)acrylic resin contained in component (A) and the hydroxyl groups of the polyol compound contained in component (B).

[0168] A polyfunctional isocyanate compound is a compound having two or more isocyanate groups (including isocyanate groups protected by leaving groups) in one molecule. In preferred polyfunctional isocyanate compounds, the number of functional groups is more preferably 2 to 6 per molecule, and even more preferably 2 to 4 per molecule.

[0169] Examples of polyfunctional isocyanate compounds include: lysine isocyanate; aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexane diisocyanate; cyclic aliphatic diisocyanates such as hydrogenated phenyl dimethylene diisocyanate, isophorone diisocyanate, methylcyclohexane-2,4-(or 2,6)-diisocyanate, 4,4'-methylene bis(cyclohexyl isocyanate) and 1,3-bis(isocyanate methyl)cyclohexane; and isocyanates with more than three functions such as lysine triisocyanate.

[0170] In addition to the polyfunctional isocyanate compounds described above, the polyfunctional isocyanate compound used as component (C) can also be a biuret-type, isocyanurate-type, adduct-type, or other polyfunctional isocyanate compound as its polymer. A biuret-type polyfunctional isocyanate compound with moderate rigidity is particularly preferred.

[0171] In this embodiment, the content of the polyfunctional isocyanate compound in the coating composition is not particularly limited as long as it is proportioned according to the equivalent ratio (NCO) / (OH) described later. Typically, it is 5 to 100 parts by weight relative to 100 parts by weight of (meth)acrylic resin, preferably 7 to 75 parts by weight, more preferably 10 to 60 parts by weight, further preferably 10 to 50 parts by weight, even more preferably 15 to 40 parts by weight, and even more preferably 20 to 30 parts by weight. It is believed that by ensuring the content of the polyfunctional isocyanate compound in the coating composition is within this range, sufficient crosslinking can be achieved within the water-absorbing antifog layer.

[0172] The molar amount (i.e., equivalent ratio (NCO) / (OH)) of the isocyanate groups (including capped isocyanate groups) contained in the polyfunctional isocyanate compound relative to the hydroxyl groups of the (meth)acrylic resin and polyol compound is preferably in the range of 0.15 to 0.55. When the equivalent ratio (NCO) / (OH) is within this range, the crosslinking density is sufficiently high, resulting in sufficient anti-fogging properties and solvent resistance as a water-absorbing anti-fogging layer.

[0173] From this perspective, the equivalence ratio (NCO) / (OH) is preferably 0.25 to 0.50, more preferably 0.35 to 0.45.

[0174] (Method of applying the composition)

[0175] The coating composition of this embodiment can be a single-component type, that is, in which all components except the solvent are substantially uniformly mixed (dissolved or dispersed) in the solvent. A single-component type is preferred when the polyfunctional isocyanate compound is a capped isocyanate.

[0176] Furthermore, as another approach, the coating composition of this embodiment can also be a two-component type. By making it a two-component type, the shelf life of the coating composition can be improved.

[0177] For example, the coating composition of this embodiment may also be composed of (1) liquid A containing (meth)acrylic resin and / or polyol compound and free of polyfunctional isocyanate compound, and (2) liquid B containing polyfunctional isocyanate compound and free of (meth)acrylic resin and polyol compound, wherein liquid A and liquid B are stored in different containers and are mixed before use (coating).

[0178] In this case, components other than (meth)acrylic resins, polyol compounds and polyfunctional isocyanate compounds (additives, etc.) can be included in liquid A, liquid B, or prepared in other containers.

[0179] Especially when the polyfunctional isocyanate compound is not a capped isocyanate (i.e., when the isocyanate group exists in the form of -NCO in the system), the coating composition is preferably a two-component type.

[0180] (solvent)

[0181] The coating composition of this embodiment may contain a solvent. By using a solvent, the viscosity and solid content of the coating composition can be easily adjusted.

[0182] Examples of solvents include: aromatic hydrocarbon solvents such as toluene and xylene; alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, tert-butanol, isobutanol, and diacetone alcohol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate, propyl acetate, butyl acetate, and isobutyl acetate; and glycol ether solvents such as propylene glycol monomethyl acetate, propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate.

[0183] Among these, tert-butanol, diacetone alcohol, methyl ethyl ketone, ethyl acetate, and propylene glycol monomethyl ether acetate are preferred from the viewpoints of low reactivity with isocyanates, solubility, and drying properties.

[0184] From the viewpoint of controlling the film thickness of the water-absorbing antifog layer, the solvent content in the coating composition is preferably 20-90% by mass, more preferably 30-85% by mass, and even more preferably 35-80% by mass.

[0185] From the viewpoint of obtaining spectacle lenses with superior anti-fog properties, the solid content of the coating composition is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. From the viewpoint of obtaining spectacle lenses with excellent appearance, it is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

[0186] From the viewpoint of improving anti-fogging and scratch resistance, the total content of components (A), (B) and (C) in the solid components of the coating composition is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and preferably 100% by mass or less, for example 100% by mass.

[0187] The coating composition can be prepared by dissolving or dispersing the above-mentioned components, ultraviolet absorbers, and other additives as needed in a solvent. Examples of such additives include curing catalysts, light stabilizers, surfactants, leveling agents, and defoamers. The content of the above-mentioned additives is preferably 0.001 to 5% by mass, more preferably 0.01 to 4% by mass, and even more preferably 0.1 to 3% by mass, relative to the total mass of the coating composition.

[0188] Each component can dissolve or disperse in the solvent simultaneously or in any order. There are no particular restrictions on the specific methods of dissolution or dispersion; any known methods can be used without any limitations.

[0189] (UV absorber)

[0190] The ultraviolet absorber contained in the above-mentioned water-absorbing anti-fog layer is an ultraviolet absorber that, when added to the water-absorbing anti-fog layer, imparts the following spectral transmittance to the water-absorbing anti-fog layer: at least less than 5% light transmittance in the 350-370 nm range; and a wavelength of 370 nm or more with a light transmittance of 5% or more.

[0191] The aforementioned water-absorbing anti-fog layer, by including the aforementioned ultraviolet absorber, can prevent the anti-fog layer from yellowing when the eyeglass lens is exposed to ultraviolet light for a long time, and can also inhibit the fading of dyes when the lens substrate is dyed.

[0192] Examples of ultraviolet absorbers include compounds represented by formula (4) and compounds represented by formula (5).

[0193] [Chemical Formula 9]

[0194]

[0195] [In equation (4), n1 is 2 or 3.]

[0196] [Chemical Formula 10]

[0197]

[0198] [In equation (5), n2 is 2 or 3, and n3 is 2 or 3.]

[0199] The compound represented by formula (4) preferably has multiple hydroxyl groups bonded to the benzene ring in a meta or para position relative to each other, preferably at least one hydroxyl group is bonded to a carbon in the ortho position relative to the carbon bonded to the benzotriazole skeleton, more preferably the hydroxyl group is bonded to carbons in the ortho and para positions relative to the carbon bonded to the benzotriazole skeleton, more preferably the hydroxyl group is bonded to a carbon in the ortho position relative to the carbon bonded to the benzotriazole skeleton, and n1 is 2.

[0200] As a specific example of the compound represented by formula (4), 2-(2,4-dihydroxyphenyl)-2H-benzotriazole (CAS No.: 22607-31-4) can be cited.

[0201] The compound represented by formula (5) preferably has multiple hydroxyl groups bonded to the benzene ring in the left and right benzene rings in a meta or para position relative to each other. Preferably, at least one hydroxyl group is bonded to a carbon that is adjacent to the carbon bonded to the carbonyl group. More preferably, the hydroxyl groups are bonded to carbons that are adjacent to and para to the carbon bonded to the carbonyl group, respectively. Even more preferably, the hydroxyl groups are bonded to carbons that are adjacent to the carbon bonded to the carbonyl group, and n2 and n3 are both 2.

[0202] As a specific example of the compound represented by formula (5), 2,2',4,4'-tetrahydroxybenzophenone (CAS No.: 131-55-5) can be cited.

[0203] The aforementioned ultraviolet absorber has high absorption performance on the long wavelength side, and when used in a water-absorbing anti-fog layer constructed using the aforementioned specific coating composition, it can exhibit high light resistance, suppress color changes in eyeglass lenses with a water-absorbing anti-fog layer, and in particular, suppress yellowing of eyeglass lenses tinted gray.

[0204] 2-(2,4-Dihydroxyphenyl)-2H-benzotriazole has the advantages of being independent of the type of monomers such as isocyanates, having low reactivity, low UV absorption efficiency, and low pot life.

[0205] Ultraviolet absorbers can be used alone or in combination with two or more.

[0206] From the viewpoint of at least one of the protection of the lens substrate and the solubility of the ultraviolet absorber, the content of the ultraviolet absorber in the above coating composition is preferably 0.01 to 5% by mass relative to the total mass of the coating composition, more preferably 0.1 to 4.5% by mass, and even more preferably 0.5 to 3% by mass.

[0207] (Other additives)

[0208] The water-absorbing anti-fog layer may also contain additives other than UV absorbers. Examples of such additives include antistatic agents and antioxidants.

[0209] The content of other additives is preferably 0.001 to 5% by mass, more preferably 0.01 to 4% by mass, and even more preferably 0.1 to 3% by mass, relative to the total mass of the coating composition.

[0210] UV absorbers and additives other than UV absorbers can be incorporated into a coating composition by adding these components to the coating composition and dissolving or dispersing them, and then coating the coating composition onto a substrate to form a water-absorbing anti-fog film.

[0211] <Other Layers>

[0212] In addition to the water-absorbing anti-fog layer, functional layers can also be set in eyeglass lenses.

[0213] Examples of such functional layers include hard coatings, anti-reflective layers, and primers.

[0214] The aforementioned functional layer can be disposed on the first main surface of the lens substrate, or on the second main surface of the lens substrate, or on both the first and second main surfaces of the lens substrate.

[0215] <Methods for Manufacturing Spectacle Lenses>

[0216] One method of manufacturing plastic eyeglass lenses includes at least the following steps (1) to (3).

[0217] • Process (1): Prepare a lens substrate made of a polymer of a polymeric composition.

[0218] • Process (2): Apply a solution containing a colorant to the surface of the above-mentioned lens substrate to dye the above-mentioned lens substrate.

[0219] • Process (3): Form a water-absorbing anti-fog layer on at least one main surface of the dyed substrate.

[0220] The following is a description of each process.

[0221] (Process (1): Preparation of lens substrate)

[0222] In step (1), a lens substrate made of the polymer of the polymeric composition is prepared by polymerizing the polymeric composition. The polymerization conditions of the polymeric composition for optical components can be appropriately set according to the polymeric composition.

[0223] The polymerization initiation temperature is preferably 0°C or higher, more preferably 10°C or higher, more preferably 50°C or lower, and even more preferably 40°C or lower. It is preferable to raise the temperature from the polymerization initiation temperature and then cure the product by heating. For example, the maximum temperature is typically 110°C or higher and 130°C or lower.

[0224] After polymerization, the eyeglass lenses can be demolded and annealed. The preferred annealing temperature is 100–150°C.

[0225] There are no particular limitations on the polymerization method; various known polymerization methods can be used, with cast polymerization being preferred. Eyeglass lenses are obtained by polymerizing, for example, a polymeric composition by injecting it into a mold made of glass or metal combined with a tape or gasket.

[0226] (Step (2): Dyeing treatment)

[0227] In step (2), a solution containing a colorant is applied to the surface of the lens substrate to dye the lens substrate. Preferably, the substrate is dyed by immersing it in a solution containing a colorant.

[0228] Dyeing can be promoted by immersing the sample in a solution containing colorant and heating it for a specified time.

[0229] (Process (3): Formation of water-absorbing anti-fog layer)

[0230] A water-absorbing anti-fog layer is formed on at least one of the first and second main surfaces of the lens substrate obtained by performing a dyeing process.

[0231] The aforementioned water-absorbing anti-fog layer is formed by coating a coating composition (in the case of a two-component type, a mixture of two liquids) on a lens substrate with the above-mentioned components dissolved or dispersed in a solvent, and then drying and curing the coating film at a specified temperature.

[0232] There are no particular limitations on the coating method. Examples include air spraying, airless spraying, electrostatic coating, roller coating, flow coating, spin coating, and dip-coating.

[0233] After coating, the film is dried and cured at 20–160°C for 10–120 minutes, preferably at 60–120°C for 20–90 minutes, and then cooled at room temperature to obtain a cured film that serves as a water-absorbing anti-fog layer. Furthermore, the drying and curing temperature and time can be appropriately adjusted considering factors such as the type of solvent and the heat resistance of the lens substrate.

[0234] In addition, depending on the needs, the above-mentioned functional layers (hard coating, primer, anti-reflective layer, etc.) can also be formed.

[0235] (Processing steps)

[0236] Before forming a water-absorbing anti-fog layer on at least one of the first and second main surfaces of the lens substrate, or after forming a water-absorbing anti-fog layer on at least one of the first and second main surfaces of the lens substrate, the lens edge is cut, ground, or otherwise processed as needed. This is how spectacle lenses are manufactured.

[0237] Example

[0238] The invention will now be described in further detail by way of examples, but the invention is not limited to these examples in any way.

[0239] The present invention will be further described in detail below through examples. The hydroxyl value, number-average molecular weight (Mn), mass-average molecular weight (Mw), and polydispersity index (Mw / Mn) of the components obtained in the following examples were determined by the following methods. Furthermore, the thickness of the water-absorbing anti-fog layer of the spectacle lenses obtained in the examples and comparative examples and the lightfastness test were performed according to the following steps.

[0240] (hydroxyl value)

[0241] The determination and calculation were performed according to the method specified in "7.1 Neutralization Titration Method" of JIS K 0070 "Test Methods for Acid Value, Saponification Value, Ester Value, Iodine Value, Hydroxyl Value and Non-Saponifiables of Chemical Products".

[0242] In addition, the acid value used in the calculation of the hydroxyl value was determined and calculated according to the method specified in "3.1 Neutralization Titration Method" of the above-mentioned JIS standard.

[0243] (Number average molecular weight (Mn), mass average molecular weight (Mw), polydispersity index (Mw / Mn))

[0244] The determination and calculation were performed using gel permeation chromatography (GPC). The apparatus and conditions used are described below.

[0245] • Instrument used: HLC8220GPC (manufactured by Tosoh Corporation)

[0246] Column used: TSKgel SuperHZM-M, TSKgel GMHXL-H, TSKgel G2500HXL, TSKgelG5000HXL (manufactured by Tosoh Corporation)

[0247] Column temperature: 40℃

[0248] Standard materials: TSKgel standard polystyrene A1000, A2500, A5000, F1, F2, F4, F10 (manufactured by Tosoh Corporation)

[0249] • Detector: RI (Differential Refractive Index) detector

[0250] • Eluent: Tetrahydrofuran

[0251] • Flow rate: 1 ml / min

[0252] (Thickness of the water-absorbing anti-fog layer)

[0253] The thickness of the water-absorbing anti-fog layer was measured using a non-contact film thickness measurement system FF8 manufactured by SystemRoad Co. Ltd.

[0254] (Spectral transmittance of the water-absorbing anti-fog layer)

[0255] As the substrate for measurement, a MERIA (manufactured by Hoya Corporation, refractive index 1.60, power S-4.00D, thickness 1.0 mm, outer diameter 75 mm) thiopolyurethane-based plastic lens with a light transmittance of 85% or more in the 350-460 nm range and without internally added ultraviolet absorbers was used as the substrate. A water-absorbing anti-fog layer was formed on this substrate according to the steps shown in the examples or comparative examples described later. Then, the spectral transmittance of each substrate with the water-absorbing anti-fog layer was measured using a UH4150 ultraviolet-visible-near-infrared spectrophotometer manufactured by Hitachi Advanced Technology & Science Co., Ltd., and the spectral transmittance of the water-absorbing anti-fog layer was thus used as the spectral transmittance of the water-absorbing anti-fog layer.

[0256] (Lightfastness test)

[0257] According to the radiation resistance test specified in JIS T7333 6.5 and 7.7, each sample was irradiated with light for 50 hours, and the visual transmittance before and after light irradiation was measured using a UH4150 UV-Vis-NIR spectrophotometer manufactured by Hitachi High Tech Scientific Co., Ltd. Furthermore, for Example 1 and Comparative Example 2 described later, the chromaticity and lightness before and after light irradiation were calculated based on the measurement results of the UH4150 UV-Vis-NIR spectrophotometer manufactured by Hitachi High Tech Scientific Co., Ltd.

[0258] [Example 1]

[0259] (Synthesis of (meth)acrylic resins)

[0260] Add 150 parts by weight of propylene glycol monomethyl ether acetate (PGMAC) to a 500 ml flask equipped with a stirrer, thermometer, condenser and nitrogen inlet tube, and heat to 110 °C.

[0261] Separately mix 25 parts by weight of dimethacrylamide (DMAA), 35 parts by weight of polycaprolactone-modified hydroxyethyl acrylate (PLACCEL FA2D, manufactured by Daicel Co., Ltd.), 10 parts by weight of 2-hydroxyethyl methacrylate (HEMA), 5 parts by weight of mono-terminated methacrylate-modified polydimethylsiloxane (Silaplane FM-0721, molecular weight 5000, manufactured by JNC Co., Ltd.), 25 parts by weight of methyl methacrylate, and 1 part by weight of 1,1'-azobis(cyclohexane-1-carboxynitrile) (Wako Pure Chemical Industries Co., Ltd., V-40). Add this monomer mixture dropwise to the aforementioned 500 ml flask over 2 hours with stirring, and allow the reaction to proceed for 5 hours.

[0262] Stop heating and cool to room temperature to obtain a resin solution containing (meth)acrylic resin (solid content ratio: about 40% by mass).

[0263] The obtained (meth)acrylic resin has a hydroxyl value of 57 mgKOH / g, a number-average molecular weight (Mn) of 12000, a mass-average molecular weight (Mw) of 44000, and a polydispersity index (Mw / Mn) of 3.67. Furthermore, based on the above Fox formula, the glass transition temperature (Tg) of the (meth)acrylic resin, calculated from the proportions of the monomers used, is 32.8 °C.

[0264] (Preparation of the coating composition)

[0265] 100 parts by weight of the above-obtained (meth)acrylic resin, 30 parts by weight of polycaprolactone diol (manufactured by Daicel Co., Ltd., PLACEL 205U, molecular weight 530, hydroxyl value 207-217 mgKOH / g), and 23.5 parts by weight of a polyfunctional isocyanate compound (manufactured by Asahi Kasei Corporation, 24A-100, hexamethylene diisocyanate biuret type, isocyanate group content 23.5% by weight, solids content 100% by weight) were mixed. The solids concentration was then adjusted using PGMAC to prepare a composition with a solids content of 30% by weight.

[0266] In addition, the amount of (meth)acrylic resin is not the amount of resin solution (solid content ratio: about 40% by mass), but rather the amount of resin (solid content) contained in the resin solution. The amount of polyfunctional isocyanate compound is also expressed as the amount of solid content.

[0267] Furthermore, the hydroxyl value of the mixture when the above-mentioned (meth)acrylic resin and polyol compound are uniformly mixed in the above-mentioned amounts is 93 mgKOH / g.

[0268] An ultraviolet absorber, 2-(2,4-dihydroxyphenyl)-2H-benzotriazole (CAS No.: 22607-31-4), was added to the above composition at a mass of 2% by mass relative to the total mass of the coating composition, and mixed to prepare a coating composition containing an ultraviolet absorber.

[0269] (Form of a water-absorbing anti-fog layer)

[0270] Using MERIA (manufactured by Hoya Corporation, refractive index 1.60, power S-4.00D, thickness 1.0mm, outer diameter 75mm) as a substrate, the following steps were performed for coloring. First, in 1000ml of pure water, (i) 2.15g of blue dye (AUL-S manufactured by Futaba Sangyo Co., Ltd.), 0.38g of red dye (BL manufactured by Futaba Sangyo Co., Ltd.), 0.31g of brown dye (SN manufactured by Futaba Sangyo Co., Ltd.), and 0.18g of yellow dye (YLSE manufactured by Kiwa Chemical Co., Ltd.) and (ii) 100ml of a solution prepared by diluting 78g of dioxybenzone (CAS No.: 131-53-3) as a carrier material with 10L of pure water were mixed to prepare the dyeing impregnation solution. The plastic lens was immersed in the dyeing solution, dyed at 92°C for 60 minutes, and then annealed at 115°C for 30 minutes, thereby coloring the plastic lens gray.

[0271] Using a gray-colored plastic lens as a substrate, the above-described coating composition is applied to the substrate by dip-coating. The coating is then cured by heating at 120°C for 2 hours, thereby forming a single-layer water-absorbing anti-fog layer on the substrate. The thickness of the water-absorbing anti-fog layer is 11.3 μm.

[0272] The substrate with the water-absorbing anti-fog layer has a light transmittance of less than 5% in the 350-370nm range, and the wavelength at which the light transmittance reaches 5% is 373.7nm.

[0273] [Example 2]

[0274] As an ultraviolet absorber, 2,2',4,4'-tetrahydroxybenzophenone (CAS No.: 131-55-5) was used, with its amount relative to the total mass of the coating composition being 3% by mass. Otherwise, a monolayer of water-absorbing antifog layer was formed by the same steps as in Example 1 to make eyeglass lenses.

[0275] The thickness of the water-absorbing anti-fog layer is 12.6 μm.

[0276] The water-absorbing anti-fog layer has a light transmittance of less than 5% in the 350-370nm range, and the wavelength at which the light transmittance reaches 5% is 382.1nm.

[0277] [Comparative Example 1]

[0278] As an ultraviolet absorber, 2,2'-dihydroxy-4-methoxybenzophenone (CAS No.: 131-53-3) was used, with its amount being 3% by mass relative to the total mass of the coating composition. Otherwise, the spectacle lens was made by the same steps as in Example 1.

[0279] The thickness of the water-absorbing anti-fog layer is 12.8 μm.

[0280] The water-absorbing anti-fog layer has a light transmittance of less than 5% in the 350-360nm range, and the wavelength at which the light transmittance reaches 5% is 363.1nm.

[0281] [Comparative Example 2]

[0282] The above composition before the addition of the ultraviolet absorber was used as the coating composition, and the eyeglass lenses were made by the same steps as in Example 1.

[0283] The thickness of the water-absorbing anti-fog layer is 12.4 μm.

[0284] The water-absorbing anti-fog layer has a light transmittance of over 80% in the 350–420 nm range.

[0285] The results of the lightfastness tests for Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1. Furthermore, the lightness and chromaticity before and after the lightfastness tests for Examples 1 and Comparative Examples 2 are shown in Table 2. Additionally, the light transmittance of the water-absorbing anti-fog layer in Comparative Example 2 was consistently greater than 5% at least in the 350–420 nm range; therefore, it is marked as "-" in the "Wavelength at which light transmittance reaches 5%" column of Tables 1 and 2.

[0286] [Table 1]

[0287] Table 1

[0288]

[0289] [Table 2]

[0290] Table 2

[0291]

[0292] As shown in Table 1, compared with Comparative Examples 1 and 2, the increase in visual transmittance of the lenses after light irradiation in Examples 1 and 2 was suppressed, and the stained lenses were less prone to fading. In particular, it can be seen that Example 2 suppressed the increase in visual transmittance to a low degree.

[0293] Furthermore, as shown in Table 2, the lens of Example 1 maintains its chromaticity (a) even after light irradiation. ＊ and b ＊ The value of (b) did not change significantly, nor did the color change significantly. In contrast, it can be seen that the lens of Comparative Example 2, because it does not contain an ultraviolet absorber, showed no significant change in b after light irradiation. ＊ The value increased significantly, causing the lens to turn yellow due to light exposure.

[0294] Finally, the embodiments of the present invention are summarized.

[0295] An eyeglass lens according to an embodiment of the present invention comprises: a substrate having first and second main surfaces; a water-absorbing anti-fog layer consisting of a single layer formed on the second main surface side of the substrate; a light-transmitting rigid layer formed on the first main surface of the substrate; and a hydrophilic anti-fog layer formed on the light-transmitting rigid layer.

[0296] According to the above embodiments, eyeglass lenses with excellent anti-fog and scratch resistance can be provided.

[0297] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the invention is not limited to the foregoing description, but is indicated by the claims and is intended to include all modifications with the same meaning and scope as those claims.

[0298] In this invention, the examples, contents, and various physical properties of the above-mentioned components can be arbitrarily combined with the items described in the detailed description of the invention as examples or preferred scope.

[0299] Furthermore, if the composition described in the embodiments is adjusted in the manner described in the detailed description of the invention, the disclosed implementation can be carried out in the same way as the embodiments throughout the entire composition of the claims.

[0300] Explanation of reference numerals in the attached figures

[0301] 10: Eyeglass lenses

[0302] 11: Substrate

[0303] 11a, 11b: Stained areas

[0304] 20, 21: Water-absorbing anti-fog layer

Claims

1. An eyeglass lens having a substrate and a water-absorbing antifog layer provided as an outermost layer on the substrate, the water-absorbing antifog layer contains an ultraviolet absorber, the water-absorbing antifog layer has a spectral property that the light transmittance is less than 5% at least in the range of 350 to 370 nm, and the wavelength at which the light transmittance is 5% or more is 370 nm or more, the ultraviolet absorber contains a compound represented by the following general formula (4) and / or a compound represented by the following general formula (5), in formula (4), n1 is 2 or 3, in formula (5), n2 is 2 or 3, and n3 is 2 or 3.

2. The spectacle lens according to claim 1, wherein, the water-absorbing antifog layer is composed of a cured film of a coating composition containing components (A) to (C) described below, component (A): a (meth)acrylic resin (A) having a structural unit derived from a monomer (a-1) represented by the following general formula (1), a structural unit derived from a monomer (a-2) represented by the following general formula (2), a structural unit derived from a (meth)acrylic acid hydroxyalkyl ester (a-3), and a structural unit derived from a monomer (a-4) represented by the following general formula (3), component (B): a polyol compound (B), component (C): a polyfunctional isocyanate compound (C), in general formula (1), R1 is a hydrogen atom or a methyl group, and R2 and R3 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 3 carbon atoms, in general formula (2), R4 is a hydrogen atom or a methyl group, and m is an integer of 1 to 5, in general formula (3), R5 is a hydrogen atom or a methyl group, R6 is a divalent organic group, and n is an integer of 0 or more.

3. The spectacle lens according to claim 1 or 2, wherein, the substrate is dyed with a coloring agent.

4. The spectacle lens according to claim 3, wherein, the substrate is dyed in gray.

5. The spectacle lens according to claim 1 or 2, wherein, the substrate is made of resin.

6. The spectacle lens according to claim 1 or 2, wherein, the water-absorbing antifog layer is a single-layered layer composed of a resin material having water-absorbing properties, and the water-absorbing antifog layer is a single-layered layer having a contact angle with water of 85 to 120°.

7. The spectacle lens according to claim 1 or 2, wherein, the thickness of the water-absorbing antifog layer is 1 to 100 μm.

8. The spectacle lens according to claim 2, wherein, the ratio (NCO) / (OH) of the number of isocyanate groups (NCO) contained in the component (C) to the total number (OH) of the number of hydroxyl groups contained in the component (A) and the number of hydroxyl groups contained in the component (B) is 0.15 or more and 0.55 or less.

9. The spectacle lens according to claim 2, wherein, the (meth)acrylic resin contains 20 to 65 mass% of the structural unit derived from the monomer (a-1) with respect to the total structural units of the (meth)acrylic resin.

10. The spectacle lens according to claim 2, wherein, in the (meth)acrylic resin, 10 to 40 mass% of the structural unit derived from the monomer (a-2) is contained with respect to the total structural units of the (meth)acrylic resin.

11. The spectacle lens according to claim 2, wherein, the (meth)acrylic resin contains 1 to 30 mass% of the structural unit derived from the monomer (a-3) with respect to the total structural units of the (meth)acrylic resin.

12. The spectacle lens according to claim 2, wherein, the (meth)acrylic resin has a hydroxyl value of 40 to 150 mgKOH / g.

13. The spectacle lens according to claim 2, wherein, the (meth)acrylic resin contains 1 to 10 mass% of the structural unit derived from the monomer (a-4) with respect to the total structural units of the (meth)acrylic resin.

14. The spectacle lens according to claim 2, wherein, The mass average molecular weight (Mw) of the (meth)acrylic resin is 10,000 to 100,000.

15. The spectacle lens according to claim 2, wherein, The hydroxyl value of the polyol compound is 50 to 500 mgKOH / g.

16. The spectacle lens according to claim 2, wherein, The mass average molecular weight (Mw) of the polyol compound is 450 to 2,500.

17. The spectacle lens of claim 2, wherein, The content of the polyol compound in the coating composition is 5 to 200 parts by mass relative to 100 parts by mass of the (meth)acrylic resin.

18. The spectacle lens of claim 2, wherein, As the polyol compound, a polycaprolactone polyol is included.

19. The spectacle lens of claim 2, wherein, The content of the polyfunctional isocyanate compound in the coating composition is 5 to 100 parts by mass relative to 100 parts by mass of the (meth)acrylic resin.

20. The spectacle lens according to claim 1 or 2, wherein, The content of the ultraviolet absorber in the coating composition is 0.01 to 5 mass% relative to the total mass of the coating composition.

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