Method for producing lens

Abstract

The purpose of the present disclosure is to provide a method for producing a lens which includes a hard coat layer in which nonuniformities are suppressed in a center section and an outer-peripheral section of the lens. This method for producing a lens according to the present disclosure includes: a step 1 for subjecting a base material including a plastic lens to a pre-wetting process by using a pre-wetting solution which contains a first solvent having a boiling point of 60-100°C and a second solvent having a boiling point of 150-210°C, the content of the second solvent with respect to the total amount of the first solvent and the second solvent being more than 20 mass%; and a step 2 for forming a hard coat layer using a hard coat layer-forming composition containing the second solvent on the base material which has been subjected to the pre-wetting process.

Description

Lens manufacturing method

[0001] The present disclosure relates to a method for manufacturing a lens.

[0002] Patent Document 1 discloses a method for applying a hard coat to a plastic lens, and discloses a method for activating the surface of the plastic lens when spin-coating the hard coat liquid.

[0003] Japanese Patent Application Publication No. 05-019103

[0004] The present disclosure relates to a method for manufacturing a lens, the method comprising: Step 1 performing a prewetting treatment on a substrate including a plastic lens using a prewetting liquid containing a first solvent having a boiling point of 60 to 100°C and a second solvent having a boiling point of 150 to 210°C, wherein the content of the second solvent relative to the total amount of the first solvent and the second solvent is more than 20 mass %; and Step 2 forming a hard coat layer on the substrate that has been subjected to the prewetting treatment using a hard coat layer-forming composition containing the second solvent.

[0005] 1 is a cross-sectional view of one embodiment of a lens obtained by the lens manufacturing method of the present disclosure.

[0006] The manufacturing method of the lens of the present disclosure will be described in detail below. The hard coat layer included in the lens is required to be formed uniformly and without unevenness in the center of the lens. Furthermore, in a lens having a hard coat layer formed thereon, unevenness in the outer periphery of the lens is also required to be suppressed. The manufacturing method of the lens of the present disclosure can manufacture a lens having the above characteristics.

[0007] In this specification, the term "to" is used to mean that the numerical values ​​before and after it are included as the lower and upper limits. In addition, in this specification, the refractive index is the refractive index at the e-line.

[0008] <Lens Manufacturing Method> The lens manufacturing method of the present disclosure includes the above-described steps 1 and 2. The procedure of each step will be described below.

[0009] [Step 1] The lens manufacturing method of the present disclosure includes Step 1. Step 1 is a step of performing a prewetting treatment on a substrate including a plastic lens using a prewetting liquid. After describing the substrate and the prewetting liquid, a method for performing Step 1 will be described.

[0010] (Substrate) The substrate used in step 1 includes a plastic lens. The substrate is not particularly limited as long as it includes a plastic lens, and may include other layers. For example, the substrate used in step 1 may be a substrate in which other layers are formed on a plastic lens. Examples of the other layers include a primer layer. Below, the plastic lens and the primer layer that may be included in the substrate will be described.

[0011] The plastic lens is not particularly limited, and conventionally known plastic lenses can be used. Preferred examples of plastic lenses include plastic lenses for spectacles. The type of plastic lens is not particularly limited. For example, when the plastic lens is for spectacles, examples include finished lenses in which both the convex and concave surfaces are optically finished and molded to the desired power, semi-finished lenses in which only the convex surface is finished as an optical surface (spherical, rotationally symmetric aspherical, progressive, etc.), and semi-finished lenses in which the concave surface is processed and polished to match the wearer's prescription. The type of plastic (so-called resin) contained in the plastic lens is not particularly limited. Examples include (meth)acrylic acid ester resins, thiourethane resins, allyl resins, episulfide resins, polycarbonates, urethane resins, polyesters, polystyrene, polyethersulfone, poly-4-methylpentene-1, and diethylene glycol bisallyl carbonate resins (CR-39). Of these, thiourethane resins, episulfide resins, and diethylene glycol bisallyl carbonate resins are preferably used. The thiourethane resin is obtained from a polyisocyanate compound and a polythiol compound. As the polyisocyanate compound, it is preferable to use at least one selected from m-xylylene diisocyanate, a mixture of 2,5-bis(isocyanatomethyl)-bicyclo[2,2,1]heptane and 2,6-bis(isocyanatomethyl)-bicyclo[2,2,1]-heptane, isophorone diisocyanate, hexamethylene diisocyanate, and tolylene diisocyanate. As the polythiol compound, it is preferable to use at least one selected from pentaerythritol tetrakis(3-mercaptopropionate), 1,2-bis[(2-mercaptoethyl)thio]-3-mercaptopropane, and a mixture of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane.The episulfide resin is obtained by ring-opening polymerization of a monomer having an episulfide group (also referred to as an epithio group) or a mixed monomer containing such a monomer. As the monomer having an episulfide group, it is preferable to use at least one selected from bis(2,3-epithiopropyl) sulfide and bis(2,3-epithiopropyl) disulfide.

[0012] The thickness of the plastic lens is not particularly limited, but is often about 1 to 30 mm from the viewpoint of ease of handling. The size of the plastic lens is not particularly limited, but is often 1 to 200 mm. When the plastic lens is for eyeglasses, the size of the plastic lens is often 50 to 100 mm. The refractive index of the plastic lens is not particularly limited, but is often 1.50 or higher, preferably 1.60 to 1.80, and more preferably 1.60 to 1.74.

[0013] The plastic lens is preferably translucent and may be either transparent or opaque. The plastic lens may also be colored.

[0014] The plastic lenses may contain additives such as bluing agents, light stabilizers, UV absorbers, and antioxidants.

[0015] The substrate may include a primer layer. The primer layer improves the adhesion of the hard coat layer formed in step 2 (described below) to the plastic lens, and can impart impact resistance to the resulting lens. As described below, the primer layer may be formed on only one side of the plastic lens, or on both sides of the plastic lens.

[0016] The material constituting the primer layer is not particularly limited, and known materials can be used, for example, resins are mainly used. The type of resin used is not particularly limited, and examples thereof include polyurethane resins, polyester resins, and polyvinyl alcohol, with polyurethane resins being preferred.

[0017] The primer layer may contain components other than the resin, such as fine particles of an oxide of at least one metal selected from Si, Al, Sn, Sb, Ta, Ce, La, Fe, Zn, W, Zr, In, and Ti, or fine particles of a composite oxide thereof, a hydrolyzable silicon compound and / or its hydrolyzed condensate, and a surfactant.

[0018] The method for forming the primer layer is not particularly limited, and known methods can be used, such as a method in which a primer layer-forming composition containing a predetermined resin is applied to a plastic lens, and a curing treatment is performed as necessary to form a primer layer. The method for applying the primer layer-forming composition is not particularly limited, and examples thereof include the methods exemplified by the method of applying the hard coat layer-forming composition to the substrate in the subsequent step. The thickness of the primer layer is not particularly limited, but is preferably 0.3 to 2 μm.

[0019] (Prewet Liquid) The prewet liquid used in step 1 contains a first solvent having a boiling point of 60 to 100°C and a second solvent having a boiling point of 150 to 210°C, with the content of the second solvent exceeding 20% ​​by mass relative to the total amount of the first and second solvents. The hard coat layer-forming composition described below also contains the second solvent. When the prewet liquid contains the second solvent, the second solvent is more likely to remain on the substrate surface in step 2 described below. Furthermore, due to its excellent compatibility with the hard coat layer-forming composition, it is believed that the hard coat layer-forming composition is more likely to uniformly wet and spread over the substrate surface when applied. When the hard coat layer-forming composition uniformly wets and spreads over the substrate surface, a hard coat layer can be uniformly formed at the center of the resulting lens, resulting in reduced unevenness. When the prewet liquid contains the first solvent, it is believed that the prewet liquid has appropriate volatility. In general, it can be said that the thickness of the coating film of the prewet liquid formed by the prewet treatment tends to be thicker near the outer periphery of the substrate than at the center of the substrate. Here, it is thought that if the prewet liquid has appropriate volatility, the thickness of the coating film of the prewet liquid at the outer periphery of the substrate will not become too thick, and when the hard coat layer-forming composition is applied in step 2, the amount of the coating film of the hard coat layer-forming composition at the outer periphery of the substrate can be adjusted to an appropriate amount. As a result, it is thought that unevenness at the outer periphery of the obtained lens will be suppressed.

[0020] In the prewet liquid, the total amount of the first solvent and the second solvent relative to the total mass of the prewet liquid is preferably 50 mass% or more, more preferably 80 mass% or more, and even more preferably 90 mass% or more. In the prewet liquid, the total amount of the first solvent and the second solvent relative to the total mass of the prewet liquid may be 100 mass%. That is, the prewet liquid may be composed of the first solvent and the second solvent.

[0021] In this disclosure, the boiling point is the temperature at 1 atmosphere (1.01325×10 ５ The boiling point is the temperature at which the saturated vapor pressure of a substance in a liquid state at a pressure (MPa) is equal to 1 atmosphere. The saturated vapor pressure may be measured at 1 atmosphere, or literature values ​​may be referenced.

[0022] The boiling point of the first solvent contained in the pre-wet liquid is 60 to 100°C, preferably 60 to 80°C, and more preferably 60 to 70°C. The first solvent is not particularly limited as long as it is within the above boiling point range, but an alcohol solvent is preferred. An alcohol solvent refers to a solvent composed of a compound having one or more hydroxy groups in its molecule. An alcohol solvent preferably contains one hydroxy group in its molecule. The number of carbon atoms in the alcohol solvent used as the first solvent is preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less. The lower limit of the number of carbon atoms in the alcohol solvent used as the first solvent is preferably 1 or more. Preferred examples of the first solvent include solvents selected from the group consisting of methanol (65°C), ethanol (78°C), 2-propanol (82°C), 2-methyl-2-propanol (82°C), and 2-butanol (100°C). Methanol or ethanol is more preferred, and methanol is even more preferred. The temperature in parentheses following each of the above compounds indicates the boiling point of each compound under the above-mentioned conditions.

[0023] The first solvent may be a solvent consisting of a single compound, or a solvent consisting of two or more compounds. When a solvent consisting of two or more compounds is used as the first solvent, each solvent consisting of a simple substance of each compound satisfies the above-mentioned boiling point requirement.

[0024] The boiling point of the second solvent contained in the pre-wet liquid is 150 to 210°C, preferably 160 to 190°C, and more preferably 170 to 180°C. The second solvent is not particularly limited as long as it is within the above boiling point range, but an alcohol solvent is preferred. The alcohol solvent preferably contains one hydroxy group per molecule. The number of carbon atoms in the alcohol solvent used as the second solvent is preferably 5 or more, more preferably 6 or more. The upper limit of the number of carbon atoms in the alcohol solvent used as the second solvent is preferably 10 or less, more preferably 8 or less. The alcohol solvent used as the second solvent is also preferably a glycol ether solvent. A glycol ether solvent refers to a solvent composed of a compound containing one or more ether bonds (—O—) linking carbon atoms and one or more hydroxy groups in the molecule. The number of ether bonds contained in the glycol ether solvent is preferably 2 or less, more preferably 1. Preferred examples of the second solvent include solvents selected from the group consisting of 2-butoxyethanol (171°C), diethylene glycol monomethyl ether (193°C), and diethylene glycol monoethyl ether (196°C), with 2-butoxyethanol being more preferred. The temperature in parentheses following each of the above compounds represents the boiling point of each compound under the above-mentioned conditions. 2-butoxyethanol is also known as butyl cellosolve.

[0025] The second solvent may be a solvent consisting of a single compound, or a solvent consisting of two or more compounds. When a solvent consisting of two or more compounds is used as the second solvent, each solvent consisting of a simple substance of each compound satisfies the above-mentioned boiling point requirement.

[0026] It is also preferred that both the first and second solvents are alcohol solvents.

[0027] In addition, in the pre-wet liquid, the content of the second solvent relative to the total amount of the first solvent and the second solvent is more than 20% by mass, and the content of the second solvent relative to the total amount of the first solvent and the second solvent is preferably 50% by mass or less, more preferably less than 40% by mass, and more preferably less than 30% by mass, in order to further suppress peripheral unevenness in the obtained lens.

[0028] The pre-wet liquid may contain components (other components) other than the first solvent and the second solvent.

[0029] (Prewetting Treatment) The prewetting treatment is performed on a substrate including the above-mentioned plastic lens using the above-mentioned prewetting liquid. The prewetting treatment is not particularly limited as long as a coating film of the prewetting liquid is formed on at least one surface of the substrate. Examples of the prewetting treatment method include dipping coating, spin coating, spray coating, inkjet coating, and flow coating, and spin coating is preferred in terms of performing the prewetting treatment more uniformly.

[0030] When the prewet treatment is performed by spin coating, the prewet treatment can be performed, for example, by the following procedure. First, the substrate is placed on a spin coater equipped with a base on which the substrate can be fixed and rotated, and a prewet liquid is supplied to the surface of the substrate while the substrate is not rotating or while rotating at a low speed (200 to 400 rpm (rpm: revolutions per minute)). The prewet liquid may be supplied only near the center of rotation of the substrate, or in a spiral pattern around the center of rotation of the substrate, or over the entire surface of the substrate. Next, the substrate to which the prewet liquid has been supplied is rotated, and the prewet liquid is spread over the entire surface of the substrate. The rotation speed of the substrate can be adjusted as appropriate, but may be, for example, 700 to 1500 rpm.

[0031] The temperature of the substrate when the prewet treatment is performed is not particularly limited, but from the viewpoint of easily obtaining the effects of the prewet treatment, it is preferably 50° C. or less, and more preferably 40° C. or less. The lower limit of the substrate temperature is, for example, 10° C. or more, and may be 25° C. or more, or may be 30° C. or more. Since the prewet liquid used in the prewet treatment of the present disclosure has the configuration described above, even if the temperature of the substrate is 30° C. or more by step 3 described below, for example, the hard coat layer-forming composition is likely to wet and spread uniformly over the substrate surface due to the mechanism described above, and it is also thought that unevenness in the outer periphery of the obtained lens is suppressed.

[0032] [Step 2] The method for manufacturing a lens according to the present disclosure includes Step 2. Step 2 is a step of forming a hard coat layer on a substrate that has been subjected to a prewetting treatment, using a composition for forming a hard coat layer that includes a second solvent. After describing the composition for forming a hard coat layer, a method for carrying out Step 2 will be described.

[0033] (Hard Coat Layer-Forming Composition) The hard coat layer-forming composition used in step 2 contains the second solvent. The hard coat layer-forming composition contains, in addition to the second solvent, a component capable of forming a hard coat layer. Components that may be contained in the hard coat layer-forming composition will be described below. Note that, hereinafter, the total solid content in the hard coat layer-forming composition refers to components capable of forming a hard coat layer, and solvents such as the second solvent are not included in the solid content. Furthermore, even if a component is in a liquid state, it is calculated as a solid content as long as it is a component that constitutes a hard coat layer.

[0034] The composition for forming a hard coat layer preferably contains a silsesquioxane compound. A silsesquioxane compound is generally a silane compound having a basic skeleton represented by formula (D) obtained by hydrolyzing a trifunctional silane compound such as an alkoxysilane, a chlorosilane, or a silanol. Known structures of silsesquioxane compounds include an irregular form called a random structure, a ladder structure, a cage structure (fully condensed cage structure), and an incomplete cage structure (a partially cleaved cage structure in which some silicon atoms are missing from the cage structure or in which some silicon-oxygen bonds in the cage structure are cleaved). In the following formula (D), R ｄ represents an organic group. ｄ -SiO ３／２ The structure of the silsesquioxane compound contained in the composition for forming a hard coat layer may be any of the random structure, ladder structure, cage structure, and incomplete cage structure, or may be a mixture of multiple types of structures.

[0035] The silsesquioxane compound preferably has a polymerizable group, which is preferably a radically polymerizable group or a cationically polymerizable group.

[0036] The radical polymerizable group contained in the silsesquioxane compound is preferably a group having an ethylenically unsaturated bond. Examples of groups having an ethylenically unsaturated bond include a (meth)acryloyl group, a styryl group, and a vinyl group. When the silsesquioxane compound contains a radical polymerizable group, the equivalent weight of the radical polymerizable group contained in the silsesquioxane compound is not particularly limited, but is preferably 30 to 500 g / eq., and more preferably 30 to 150 g / eq., in terms of achieving superior hardness of the hard coat layer. The silsesquioxane compound having a radical polymerizable group may be synthesized by a known method, or a commercially available product may be used.

[0037] The cationically polymerizable group contained in the silsesquioxane compound is not particularly limited, but examples thereof include an oxetanyl group and an epoxy group.

[0038] The oxetanyl group is a group represented by the following formula (2): ２ represents a hydrogen atom or an alkyl group (for example, a methyl group, an ethyl group, or a propyl group). * represents a bonding position.

[0039]

[0040] The epoxy group is a group represented by the following formula (3): １ represents a hydrogen atom or an alkyl group (for example, a methyl group, an ethyl group, or a propyl group). * represents a bonding position.

[0041]

[0042] The specific silsesquioxane may be synthesized by a known method, or a commercially available product may be used, such as OX-SQ TX-100, OX-SQ SI-20, OX-SQ HDX, and OX-SQ ME-20, manufactured by Toagosei Co., Ltd.

[0043] The content of the silsesquioxane compound having a polymerizable group in the composition for forming a hard coat layer is not particularly limited, but is preferably 10 to 60 mass %, more preferably 20 to 55 mass %, based on the total solid content in the composition for forming a hard coat layer.

[0044] The hard coat layer-forming composition may contain metal oxide particles. The type of metal oxide particles is not particularly limited, and known metal oxide particles may be used. Examples of metal oxide particles include particles of at least one metal oxide selected from Si, Al, Sn, Sb, Ta, Ce, La, Fe, Zn, W, Zr, In, and Ti. Among these, from the viewpoint of ease of handling, metal oxide particles are preferably Si-containing oxide particles (silicon oxide particles), Sn-containing oxide particles (tin oxide particles), Zr-containing oxide particles (zirconium oxide particles), or Ti-containing oxide particles (titanium oxide particles). The metal oxide particles may contain only one of the above-mentioned metals (metal atoms) or two or more metals (metal atoms). Although Si (silicon) is sometimes classified as a semimetal, this specification defines Si as a metal.

[0045] The average particle size of the metal oxide particles is not particularly limited, but is preferably 1 to 200 nm, and more preferably 5 to 30 nm. Within this range, the dispersion stability of the metal oxide particles in the composition for forming a hard coat layer is superior, and whitening of the cured product can be further suppressed. The average particle size is determined by measuring the diameters of 100 or more metal oxide particles using a transmission electron microscope and calculating the arithmetic average. When the metal oxide particles are not perfectly circular, the major axis is used as the diameter.

[0046] Various functional groups may be introduced onto the surface of the metal oxide particles as needed.

[0047] The content of the metal oxide particles in the composition for forming a hard coat layer is not particularly limited, but is preferably 10 to 70 mass %, more preferably 25 to 55 mass %, based on the total solid content in the composition for forming a hard coat layer.

[0048] The hard coat layer-forming composition may contain a polymerizable monomer. The silsesquioxane compound having a polymerizable group is not included in the polymerizable monomer. The polymerizable monomer refers to a compound having a polymerizable group. Examples of the polymerizable monomer include a compound having a radical polymerizable group and a compound having a cationically polymerizable group. The number of polymerizable groups in the polymerizable monomer is preferably 2 to 6, and more preferably 2 to 3.

[0049] The compound having the radical polymerizable group is preferably a (meth)acrylate compound. The term "(meth)acrylate compound" refers to a concept that includes a compound containing a methacryloyl group and a compound containing an acryloyl group. The (meth)acrylate compound is preferably a polyfunctional (meth)acrylate compound having two or more radical polymerizable groups (methacryloyl groups or acryloyl groups) in the molecule, and the preferred number of polymerizable groups is as described above. The (meth)acrylate compound may also be a compound having a group selected from the group consisting of a phosphate group and a sulfonic acid group.

[0050] The polyfunctional (meth)acrylate is preferably a compound represented by formula (E): ２ =CR ｅ１ -CO-L ｅ１ -CO-CR ｅ２ =CH ２ R ｅ１ and R ｅ２ each independently represents a hydrogen atom or a methyl group. ｅ１ represents a divalent hydrocarbon group which may contain a heteroatom (for example, an oxygen atom, a nitrogen atom, or a sulfur atom). The number of carbon atoms in the divalent hydrocarbon group is not particularly limited, and is preferably 1 to 10. Examples of the divalent hydrocarbon group include alkylene groups, alkenylene groups, alkynylene groups, and arylene groups which may contain a heteroatom, and combinations of these groups, and alkylene groups which may contain a heteroatom are preferred. Among these, alkylene groups containing an oxygen atom are preferred, and -O-(L ｅ２ -O) ｒ A group represented by - is preferred.ｅ２ represents an alkylene group (preferably having 1 to 3 carbon atoms), and r represents an integer of 1 or more, preferably an integer of 1 to 10, and more preferably an integer of 2 to 5.

[0051] The (meth)acrylate compounds may be used alone or in combination of two or more.

[0052] The compound having the cationically polymerizable group is preferably an epoxy compound having an epoxy group. The epoxy group is a group represented by the above formula (3). The epoxy compound is preferably a multifunctional epoxy compound having two or more epoxy groups in the molecule, and the preferred number of polymerizable groups is as described above. The type of multifunctional epoxy compound is not particularly limited, and known multifunctional epoxy compounds can be used. Examples of multifunctional epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, phenol novolac type epoxy compounds, cresol novolac type epoxy compounds, and aliphatic glycidyl ether type epoxy compounds.

[0053] The epoxy compounds may be used alone or in combination of two or more.

[0054] The composition for forming a hard coat layer may contain at least one selected from the group consisting of hydrolyzable silicon compounds, their hydrolysates, and their hydrolysis condensates (hereinafter, also simply referred to as "hydrolyzable silicon compounds"). The hydrolyzable silicon compound refers to a compound in which a hydrolyzable group is bonded to a silicon atom. The hydrolyzable silicon compound is preferably a compound represented by formula (H). Formula (H) R ｈ１ -L ｈ -Si(R ｈ２ ) ｓ (R ｈ３ ) ３－ｓ R ｈ１ represents an epoxy group. The definition of the epoxy group is as described above.

[0055] L ｈrepresents a divalent hydrocarbon group which may contain a heteroatom. The number of carbon atoms in the hydrocarbon group is not particularly limited, and is preferably 1 to 10. Examples of the divalent hydrocarbon group include an alkylene group, an alkenylene group, an alkynylene group, an arylene group, and combinations of these groups, and an alkylene group which may contain a heteroatom is preferred.

[0056] R ｈ２ represents a hydrolyzable group. The hydrolyzable group is a group that is directly bonded to Si (silicon atom) and can undergo a hydrolysis reaction and / or a condensation reaction. Examples of the hydrolyzable group include an alkoxy group, a hydroxyl group, a halogen atom, an acyloxy group, an alkenyloxy group, and an isocyanate group. R ｈ３ represents an alkyl group. ｈ３ The number of carbon atoms in the alkyl group represented by the formula (I) is preferably 1 to 10. s represents an integer of 1 to 3. s is preferably 3.

[0057] The hydrolyzate of a hydrolyzable silicon compound refers to a compound obtained by hydrolyzing the hydrolyzable groups in the hydrolyzable silicon compound.The hydrolyzate may be one in which all of the hydrolyzable groups are hydrolyzed (complete hydrolyzate), or one in which only a portion of the hydrolyzable groups are hydrolyzed (partial hydrolyzate).In other words, the hydrolyzate may be a complete hydrolyzate, a partial hydrolyzate, or a mixture thereof.

[0058] Furthermore, the hydrolysis condensate of hydrolyzable silicon compound refers to a compound obtained by hydrolyzing the hydrolyzable group in the hydrolyzable silicon compound and condensing the obtained hydrolyzate.The above-mentioned hydrolysis condensate may be a compound in which all hydrolyzable groups are hydrolyzed and all the hydrolyzate is condensed (complete hydrolysis condensate), or a compound in which some of the hydrolyzable groups are hydrolyzed and some of the hydrolyzate is condensed (partial hydrolysis condensate).In other words, the above-mentioned hydrolysis condensate may be a complete hydrolysis condensate, a partial hydrolysis condensate, or a mixture thereof.

[0059] When the composition for forming a hard coat layer contains hydrolyzable silicon compounds, the content of the hydrolyzable silicon compounds is not particularly limited, but is preferably 0.5 to 30 mass %, more preferably 1 to 10 mass %, based on the total solid content in the composition for forming a hard coat layer.

[0060] The hard coat layer-forming composition may contain a radical polymerization initiator. Examples of the radical polymerization initiator include a photoradical polymerization initiator and a thermal radical polymerization initiator. The hard coat layer-forming composition may contain a cationic polymerization initiator. Examples of the cationic polymerization initiator include a photocationic polymerization initiator and a thermal cationic polymerization initiator.

[0061] The composition for forming a hard coat layer may contain various additives, such as an ultraviolet absorber, a surfactant, an antiaging agent, a coating film modifier, a light stabilizer, an antioxidant, a coloring inhibitor, a dye, a filler, and an internal mold release agent, as needed.

[0062] The hard coat layer-forming composition contains the second solvent, but may contain a solvent other than the second solvent. For example, the hard coat layer-forming composition may contain a first solvent. Preferred embodiments of the first solvent are as described above. The hard coat layer-forming composition may contain two or more first solvents.

[0063] The content of the solvent including the second solvent in the hard coat layer-forming composition is preferably 10 to 90% by mass, more preferably 10 to 50% by mass, based on the total mass of the hard coat layer-forming composition. The content of the second solvent in the hard coat layer-forming composition is preferably 10 to 60% by mass, more preferably 10 to 40% by mass, based on the total content of solvents in the hard coat layer-forming composition. The content of the first solvent in the hard coat layer-forming composition is preferably 40 to 90% by mass, more preferably 60 to 85% by mass, based on the total content of solvents in the hard coat layer-forming composition. The content of the total solids in the hard coat layer-forming composition is preferably 10 to 90% by mass, more preferably 40 to 80% by mass, based on the total mass of the hard coat layer-forming composition.

[0064] The viscosity of the hard coat layer-forming composition can be adjusted as appropriate, but from the viewpoint of the coatability of the hard coat layer-forming composition, it is preferably 100 mPa·s or less, more preferably 50 mPa·s or less, and even more preferably 30 mPa·s or less. The lower limit of the viscosity of the hard coat layer-forming composition is not particularly limited, but may be 1 mPa·s or more, and is often 5 mPa·s or more. According to the lens manufacturing method of the present disclosure, even when the viscosity of the hard coat layer-forming composition is 10 mPa·s or more, the hard coat layer-forming composition can be uniformly wetted and spread over the substrate surface, and a uniform hard coat layer can be formed. In the present disclosure, the viscosity of the hard coat layer-forming composition is a value at 25°C.

[0065] The hard coat layer-forming composition may be prepared by mixing the components described above. The mixing method is not particularly limited, and known methods can be used. When the hard coat layer-forming composition contains a silsesquioxane having a cationically polymerizable group and metal oxide particles, it is preferable to obtain the hard coat layer-forming composition by the following procedure in order to suppress changes in viscosity over time during storage. First, in step A, a mixture containing a silsesquioxane having a cationically polymerizable group and metal oxide particles is heat-treated at a temperature above 60°C. Next, in step B, the mixture obtained in step A is mixed with a cationic polymerization initiator to obtain a hard coat layer-forming composition. The heating temperature of the mixture in step A is preferably 60°C, more preferably 80°C or higher, even more preferably 100°C or higher, particularly preferably 120°C or higher, and most preferably 140°C or higher. The upper limit of the heating temperature is not particularly limited, and is preferably 200°C or lower. The heating temperature refers to the set temperature of a heating device (such as a hot plate) used to heat the mixture.

[0066] (Formation of hard coat layer) In step 2, a hard coat layer is formed using the above-mentioned composition for forming a hard coat layer. In step 2, the method is not particularly limited as long as a hard coat layer is formed on a substrate that has been subjected to a pre-wet treatment using the above-mentioned composition for forming a hard coat layer. Among these, the hard coat layer is preferably formed by a method in which the composition for forming a hard coat layer is applied to a substrate that has been subjected to a pre-wet treatment, a coating film made of the composition for forming a hard coat layer is formed, and the coating film of the composition for forming a hard coat layer is subjected to a curing treatment.

[0067] The method of applying the composition for forming a hard coat layer and forming a coating film of the composition for forming a hard coat layer is not particularly limited, and can be carried out by the same method as pre-wetting treatment.Among the above methods, the application of the composition for forming a hard coat layer and forming a coating film of the composition for forming a hard coat layer are preferably carried out by spin coating.Preferable methods of spin coating are as described above.

[0068] The curing treatment to be performed on the coating film of the composition for forming a hard coat layer can be selected appropriately depending on the components contained in the composition for forming a hard coat layer. Examples of the curing treatment include a heat treatment and a light irradiation treatment. The temperature of the heat treatment can be adjusted appropriately, but for example, the heating temperature is preferably 30 to 100°C, and the heating time is preferably 5 to 360 minutes. The type of light used for light irradiation is not particularly limited, but examples include ultraviolet light and visible light. Examples of the light source include a high-pressure mercury lamp. The integrated light amount used for light irradiation is not particularly limited, but from the viewpoints of productivity and curability of the coating film, it is preferably 100 to 3000 mJ / cm. ２ is preferred, and 100 to 1500 mJ / cm ２ is more preferred.

[0069] The curing treatment may be carried out after the coating film of the composition for forming a hard coat layer has been dried. Examples of the drying treatment include a heating treatment. The heating treatment in the curing treatment may also serve as the drying treatment.

[0070] The thickness of the hard coat layer to be formed is not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The upper limit of the thickness can be, for example, 30 μm or less. The thickness is an average thickness, and the measurement method is to measure the thickness at any five points on the hard coat layer and calculate the arithmetic average.

[0071] The application of the hard coat layer-forming composition is carried out on the substrate that has been subjected to the prewet treatment, but is preferably carried out while the coating film of the prewet liquid formed by the prewet treatment remains. For example, it is preferable that a treatment to remove the coating film of the prewet liquid, such as a drying treatment, is not carried out between the prewet treatment and the application of the hard coat layer-forming composition. Furthermore, it is preferable that the application of the hard coat layer-forming composition is carried out within 1 to 10 seconds after the prewet treatment, without carrying out a drying treatment or the like after the prewet treatment.

[0072] [Step 3] The method for manufacturing a lens according to the present disclosure may further include step 3, in which a drying treatment is performed on the substrate, before step 1 described above. A preferred example of the drying treatment is a treatment in which the substrate is heated. When a drying treatment such as step 3 is performed, the substrate is likely to become heated by the drying treatment, and compared to a case in which step 1 is not performed, the substrate has excellent wet spreadability when coated with a composition for forming a hard coat layer, and the effect of suppressing unevenness in the outer periphery of the obtained lens is more pronounced.

[0073] The object to be dried by the drying treatment is not particularly limited as long as it is a substrate, and the purpose of the drying treatment is not limited.For example, the drying treatment may be a treatment for removing the solvent used to clean the substrate, or may be a treatment for removing the solvent contained in the coating film formed on the plastic lens.The coating film formed on the plastic lens may be a coating film formed by a primer layer-forming composition.

[0074] The method for manufacturing a lens according to the present disclosure may also include a step of forming a lens configuration described below.

[0075] <Lens> Lenses obtained by the lens manufacturing method of the present invention will now be described. FIG. 1 is an example of a lens obtained by the lens manufacturing method of the present invention. The lens 20 shown in FIG. 1 has a plastic lens 10, a primer layer 12, a hard coat layer 14, an anti-reflection coating 16, and a water- and oil-repellent layer 18, in this order. In the lens 20 shown in FIG. 1, the primer layer 12, the hard coat layer 14, the anti-reflection coating 16, and the water- and oil-repellent layer 18 are formed, in this order, on one side of the plastic lens 10. However, in FIG. 1, the primer layer, the hard coat layer, the anti-reflection coating, and the water- and oil-repellent layer may be formed, in this order, on the surface of the plastic lens 10 opposite the primer layer 12 side. Furthermore, in the lens 20 shown in FIG. 1, any one or more of the primer layer 12, the anti-reflection coating 16, and the water- and oil-repellent layer 18 may be omitted. The plastic lens 10, the primer layer 12, and the hard coat layer 14 are as described above, and preferred embodiments are also as described above. The following describes the anti-reflection coating and water- and oil-repellent layer that may be included in the lens obtained by the lens manufacturing method of the present disclosure (hereinafter also simply referred to as the "obtained lens").

[0076] [Anti-reflection film] The obtained lens may have an anti-reflection film. The anti-reflection film is preferably disposed on the side of the hard coat layer opposite the plastic lens. The anti-reflection film is a layer that has the function of preventing reflection of incident light. Specifically, the anti-reflection film can have low reflectance characteristics (broadband low reflectance characteristics) over the entire visible range of 380 to 780 nm.

[0077] The structure of the antireflective film is not particularly limited, and may be a single-layer structure or a multilayer structure. An inorganic antireflective film is preferred as the antireflective film. An inorganic antireflective film is an antireflective film composed of an inorganic compound. In the case of a multilayer structure, a structure in which low-refractive-index layers and high-refractive-index layers are alternately stacked is preferred. Examples of materials constituting the high-refractive-index layers include oxides of titanium, zirconium, aluminum, niobium, tantalum, or lanthanum. Examples of materials constituting the low-refractive-index layers include oxides of silica. The method for producing the antireflective film is not particularly limited, and examples include dry methods such as vacuum deposition, sputtering, ion plating, ion-beam assisted deposition, and CVD.

[0078] [Water- and oil-repellent layer] The resulting lens may include a water- and oil-repellent layer. The water- and oil-repellent layer is preferably disposed as the outermost layer of the lens. The water- and oil-repellent layer reduces the surface energy of the lens, improving the lens's anti-contamination function and improving the lubricity of the lens surface, thereby improving the lens's abrasion resistance. The water- and oil-repellent layer is preferably provided when the resulting lens is a spectacle lens.

[0079] The material constituting the water- and oil-repellent layer is not particularly limited, and examples thereof include fluorine-containing compounds (compounds containing fluorine atoms) and silicon-containing compounds (compounds containing silicon atoms). Among these, the water- and oil-repellent layer preferably contains a fluorine-containing compound, and more preferably contains at least one selected from the group consisting of fluorine-substituted alkyl group-containing organosilicon compounds, their hydrolysates, and their hydrolyzed condensates. The material constituting the water- and oil-repellent layer may be used alone or in combination of two or more.

[0080] The organosilicon compound containing fluorine-substituted alkyl group is the organosilicon compound that contains alkyl group in which part or all of hydrogen atom is replaced by fluorine atom, and has hydrolyzable group.Here, the hydrolyzable group is the group that is directly bonded to silicon atom and can proceed hydrolysis reaction and condensation reaction, for example, alkoxy group, halogen atom, acyloxy group, alkenyloxy group and isocyanate group.It should be noted that when a plurality of hydrolyzable groups are directly bonded to one silicon atom, they can be the same or different.

[0081] The hydrolyzate of a fluorine-substituted alkyl group-containing organosilicon compound refers to a compound obtained by hydrolyzing the hydrolyzable groups in a fluorine-substituted alkyl group-containing organosilicon compound. The hydrolyzate may be one in which all of the hydrolyzable groups are hydrolyzed (complete hydrolyzate) or one in which only a portion of the hydrolyzable groups are hydrolyzed (partial hydrolyzate). In other words, the hydrolyzate may be a complete hydrolyzate, a partial hydrolyzate, or a mixture thereof. The hydrolyzed condensate of a fluorine-substituted alkyl group-containing organosilicon compound refers to a compound obtained by hydrolyzing the hydrolyzable groups in a fluorine-substituted alkyl group-containing organosilicon compound and condensing the resulting hydrolyzate. The hydrolyzed condensate may be one in which all of the hydrolyzable groups are hydrolyzed and the hydrolyzate is completely condensed (complete hydrolyzed condensate), or one in which only a portion of the hydrolyzable groups are hydrolyzed and a portion of the hydrolyzate is condensed (partial hydrolyzed condensate). In other words, the hydrolyzed condensate may be a complete hydrolyzed condensate, a partial hydrolyzed condensate, or a mixture thereof.

[0082] There are no particular restrictions on the thickness of the water- and oil-repellent layer of the resulting lens, but it is preferably 5 to 35 nm.

[0083] The method for forming the water- and oil-repellent layer is not particularly limited and can be selected as desired depending on the materials used, the desired performance, thickness, etc. Examples include a method in which a water- and oil-repellent layer-forming composition containing a fluorine-substituted alkyl group-containing organosilicon compound is applied to a substrate and cured as needed, and a dry method. Coating methods include, for example, dip coating, roll coating, bar coating, spin coating, spray coating, die coating, and gravure coating. Curing treatments include, for example, light irradiation treatment, heat treatment, and water vapor contact treatment. Water vapor contact treatments include, for example, contact with air controlled at a humidity of 50 to 90% RH. The above curing treatments may be performed in combination. Examples of dry methods include the same methods as those used for the antireflective coating described above.

[0084] <Applications> Lenses obtained by the lens manufacturing method of the present disclosure have a hard coat layer formed uniformly in the central portion of the lens, and unevenness in the peripheral portion of the lens is suppressed, and therefore the lenses are suitably used for various lens applications, particularly as lenses for eyeglasses.

[0085] The above-mentioned embodiments will be explained in more detail below with reference to examples and comparative examples, but the present disclosure is not limited to these examples in any way.

[0086] Example 1 Preparation of Pre-wet Liquid Methanol and 2-butoxyethanol were mixed at mass ratios of 75% by mass and 25% by mass, respectively, to obtain the pre-wet liquid used in Example 1.

[0087] [Preparation of Hard Coat Layer-Forming Composition] To a glass container equipped with a stirrer, (A) a cationically curable silsesquioxane (manufactured by Toagosei Co., Ltd.: OX-SQ TX-100) (27.13 g) as the silsesquioxane, and (B) colloidal silica (manufactured by JGC Catalysts and Chemicals Co., Ltd.: OSCAL-1432E, isopropanol dispersion, solids content 30% by mass) (90.45 g) as the metal oxide particles were added to form a mixture. The resulting mixture was stirred for 6 hours while being heated on a hot plate set to 160°C. At this time, the glass container was sealed with a lid, and the solvent in the mixture was in a reflux state.

[0088] After heating, the resulting reaction solution was cooled to room temperature overnight, and then 2-butoxyethanol (10.85 g) was added to the cooled reaction solution as a membrane-forming solvent. Next, isopropanol was distilled off from the reaction solution under reduced pressure at 40°C over 2 hours. Methanol (33.40 g) was added to the resulting crude product to obtain Liquid Composition X1.

[0089] In a glass container equipped with a stirrer, the liquid composition X1 (98.52 g) obtained in the above step 1, (D) SbF as a cationic polymerization initiator, and ６ － A composition for forming a hard coat layer was obtained by adding and mixing a (F) hydroxyphenyltriazine-based sulfonium salt (San-Aid SI-150L manufactured by Sanshin Chemical Industry Co., Ltd.) (0.52 g), a (G) hydroxyphenyltriazine-based ultraviolet absorber (Tinuvin 477 manufactured by BASF Japan Ltd.) (0.62 g) as an ultraviolet absorber, and a (G) polyether-modified silicone (DOWSIL L-7001 manufactured by Dow Corning Toray Co., Ltd.) (0.33 g) as a surfactant.

[0090] [Preparation of primer layer-forming composition] Pure water (179 parts by mass) and surfactants 501W ADDITIVE (manufactured by Dow Chemical) (1.1 parts by mass) and L7001 (manufactured by Dow Chemical) (1.1 parts by mass) were added to an aqueous urethane dispersion (Evafal HA170, manufactured by Nicca Chemical Co., Ltd., solids concentration 37% by mass) (200 parts by mass), and the mixture was stirred to obtain a primer layer-forming composition with a solids concentration of 20.0% by mass.

[0091] [Formation of Primer Layer] First, a lens with a refractive index of 1.60 (Nikon Lite AS Material S-3.00D, manufactured by Nikon Essilor Corporation) was prepared as a plastic lens. The diameter of the plastic lens was 80 mm. The substrate was placed on a spin coater, and the substrate was rotated at 500 rpm for 2 seconds. During this rotation, 2.5 mL of a primer layer-forming composition was dripped from the outer periphery of the substrate to the center. The substrate onto which the primer layer-forming composition had been dripped was then allowed to reach 600 rpm in 10 seconds, after which it was rotated for 5 seconds, and furthermore, after reaching 2000 rpm, it was rotated for 3 seconds, thereby performing a primer treatment. By performing the primer treatment, a coating film of the primer layer-forming composition was formed on the substrate.

[0092] [Prewetting Treatment] A prewetting treatment was performed on the substrate on which the primer layer was formed by the above procedure. First, the substrate was placed on a spin coater and rotated at 300 rpm for 2 seconds. During this rotation, 4 mL of the prewetting liquid used in Example 1 was dripped from the center to the outer periphery of the substrate. Then, the substrate on which the prewetting liquid had been dripped was rotated at 1000 rpm for 1 second to perform the prewetting treatment. By performing the prewetting treatment, a coating film made of the prewetting liquid was formed on the substrate. The temperature of the substrate immediately before the prewetting treatment was adjusted to 30 to 40°C.

[0093] [Formation of hard coat layer] By spin coating, the above-mentioned hard coat layer forming composition is applied to the surface of the substrate that is subjected to pre-wetting treatment according to the above-mentioned procedure to form the coating film of the pre-wetting liquid.The coating film of the hard coat layer is formed by the following steps: the substrate that is subjected to pre-wetting treatment is rotated at 300 rpm for 4 seconds, and during this rotation, 4mL of the above-mentioned hard coat layer forming composition is dropped, then the substrate that is dropped with the hard coat layer forming composition is rotated at 300 rpm for 15 seconds, then the rotation speed is increased to 400 rpm in 5 seconds, then the rotation speed is increased to 700 rpm in 5 seconds, then the rotation speed is increased to 2000 rpm in 9.9 seconds, then the rotation speed is increased to 1 second, then the rotation speed is increased to 2000 rpm in 9.9 seconds, then the rotation speed is increased to 1 second.

[0094] After forming a coating film of the composition for forming a hard coat layer by the above procedure, the substrate was heated at 80°C for 20 minutes and then further heated at 100°C for 1 hour to form a cured film, thereby obtaining a lens. The thickness of the formed cured film was 15 µm.

[0095] [Evaluation] (Uniformity) The presence or absence of unevenness in the hard coat layer was observed under a fluorescent lamp and an ultra-high pressure mercury lamp in an area with a radius of 30 mm from the center of the lens obtained by the above procedure, and the uniformity of the formed hard coat layer was evaluated according to the following evaluation criteria. In practice, ratings A to C are preferable. A: No unevenness is observed under either the ultra-high pressure mercury lamp or the fluorescent lamp. B: Light unevenness is observed only under the ultra-high pressure mercury lamp, and no unevenness is observed under the fluorescent lamp. C: Light unevenness and dark unevenness are observed under the ultra-high pressure mercury lamp, and light unevenness is observed under the fluorescent lamp, but no dark unevenness is observed. D: Light unevenness and dark unevenness are observed under both the ultra-high pressure mercury lamp and the fluorescent lamp.

[0096] (Peripheral Unevenness) The region of the lens obtained by the above procedure, from a position 30 mm radius from the center to the periphery of the lens (a region 10 mm from the periphery of the lens toward the center of the lens), was observed for the presence or absence of unevenness in the hard coat layer under a fluorescent lamp and an ultra-high pressure mercury lamp, and the uniformity of the formed hard coat layer was evaluated according to the following evaluation criteria. In practice, ratings A to C are preferable. A: No unevenness is observed under either the ultra-high pressure mercury lamp or the fluorescent lamp. B: Light unevenness is observed only under the ultra-high pressure mercury lamp, and no unevenness is observed under the fluorescent lamp. C: Light unevenness and dark unevenness are observed under the ultra-high pressure mercury lamp, and light unevenness is observed under the fluorescent lamp, but no dark unevenness is observed. D: Light unevenness and dark unevenness are observed under both the ultra-high pressure mercury lamp and the fluorescent lamp.

[0097] <Comparative Example 1 and Examples 2 to 5> Prewetting treatment and formation of a hard coat layer were carried out in the same manner as in Example 1, except that the composition of the prewetting liquid was changed as shown in the table below. However, for Comparative Example 1, evaluation of peripheral unevenness was not carried out. Evaluation was also carried out in the same manner as in Example 1. The evaluation results are shown in the table below.

[0098] <Comparative Example 2> Prewetting treatment and formation of a hard coat layer were performed in the same manner as in Example 1, except that the prewetting liquid was changed to 100% by mass of methanol. Furthermore, the uniformity of the hard coat layer was evaluated in the same manner as in Example 1. Evaluation of peripheral unevenness was not performed. The evaluation results are shown in the table below.

[0099] Comparative Example 3 A pre-wet treatment and formation of a hard coat layer were carried out in the same manner as in Example 1, except that the pre-wet liquid was changed to 100% by mass of 2-butoxyethanol. Evaluation was also carried out in the same manner as in Example 1. The evaluation results are shown in the table below.

[0100] <Results> The composition of the pre-wet liquid used in each example and each comparative example, as well as the evaluation results, are shown in the table. In Table 1, the notation "-" in the "Pre-wet Liquid" column indicates that the corresponding solvent was not used. Furthermore, the content of each component in the "First Solvent" and "Second Solvent" columns is a percentage based on mass. Furthermore, in Table 1, the notation "-" in the "Evaluation" column indicates that the corresponding evaluation was not performed.

[0101]

[0102] The results shown in the table confirm that when a pre-wet liquid containing a first solvent having a predetermined boiling point and a second solvent having a predetermined boiling point is used, and the content of the second solvent relative to the total amount of the first and second solvents is greater than 20% by mass, the uniformity of the hard coat layer evaluated as (uniformity) above is excellent, and the occurrence of peripheral unevenness is suppressed. On the other hand, when the content of the second solvent relative to the total amount of the first and second solvents in the pre-wet liquid is 20% by mass or less, or when the pre-wet liquid does not contain the second solvent, the uniformity of the hard coat layer evaluated as (uniformity) above is poor. Furthermore, when the pre-wet liquid does not contain the first solvent, peripheral unevenness is confirmed to occur. Comparing Examples 1 to 3 with Examples 4 and 5, it is confirmed that when the content of the second solvent relative to the total amount of the first and second solvents is less than 40% by mass (preferably less than 30% by mass), the uniformity of the hard coat layer evaluated as (uniformity) above is excellent, and the occurrence of peripheral unevenness is further suppressed.

[0103] 10 Plastic lens 12 Primer layer 14 Hard coat layer 16 Anti-reflection film 18 Water- and oil-repellent layer 20 Lens

Claims

1. A method for manufacturing a lens, comprising: step 1 of performing a pre-wetting treatment on a substrate including a plastic lens using a pre-wetting liquid containing a first solvent having a boiling point of 60 to 100°C and a second solvent having a boiling point of 150 to 210°C, the content of the second solvent being more than 20 mass% relative to the total amount of the first solvent and the second solvent; and step 2 of forming a hard coat layer on the substrate that has been subjected to the pre-wetting treatment, using a composition for forming a hard coat layer containing the second solvent.

2. The method of claim 1, wherein the first solvent and the second solvent are alcohol solvents.

3. The method for manufacturing a lens according to claim 1 or 2, wherein the first solvent is a solvent selected from the group consisting of methanol, ethanol, 2-propanol, 2-methyl-2-propanol, and 2-butanol.

4. A method for manufacturing a lens according to any one of claims 1 to 3, wherein the second solvent is a solvent selected from the group consisting of 2-butoxyethanol, diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether.

5. The method for producing a lens according to any one of claims 1 to 4, wherein the composition for forming a hard coat layer contains the first solvent.

6. The method for manufacturing a lens according to any one of claims 1 to 5, wherein the pre-wetting process is a process of spin-coating the pre-wetting liquid.

7. A method for manufacturing a lens according to any one of claims 1 to 6, wherein in the pre-wet liquid, the content of the second solvent relative to the total amount of the first solvent and the second solvent is more than 20 mass % and less than 30 mass %.

8. The method for manufacturing a lens according to any one of claims 1 to 7, further comprising a step of performing a drying treatment on the substrate before step 1.

9. The method for producing a lens according to any one of claims 1 to 8, wherein the composition for forming a hard coat layer contains a silsesquioxane compound.

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