Lens manufacturing method

Abstract

The purpose of the present invention is to provide a method for manufacturing a lens including a hard coat layer, which suppresses the occurrence of unevenness in the central portion and the outer peripheral portion of the lens. A method for producing a lens according to the present invention comprises: a step 1 in which a substrate comprising a plastic lens is subjected to a pre-wetting treatment using a pre-wetting solution containing a first solvent having a boiling point of 60-100 DEG C and a second solvent having a boiling point of 150-210 DEG C, the content of the second solvent being greater than 20 mass% with respect to the total amount of the first solvent and the second solvent; and a step 2 in which a hard coat layer is formed on the substrate subjected to the pre-wetting treatment using a hard coat layer-forming composition containing a second solvent.

Description

Technical Field

[0001] This invention relates to a method for manufacturing lenses. Background Technology

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

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 05-019103 Summary of the Invention

[0006] This invention relates to a method for manufacturing a lens, comprising: step 1, wherein a substrate comprising a plastic lens is pre-wetting treated with 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, and the content of the second solvent relative to the combined amount of the first solvent and the second solvent is greater than 20% by mass; and step 2, wherein a hard coating is formed on the pre-wetting substrate using a hard coating forming composition containing the second solvent. Attached Figure Description

[0007] Figure 1 This is a cross-sectional view of one embodiment of a lens obtained by the lens manufacturing method of the present invention. Detailed Implementation

[0008] The manufacturing method of the lens of the present invention will be described in detail below.

[0009] The hard coating contained in the lens must be uniformly formed without unevenness in the center of the lens. Furthermore, for lenses with a hard coating, it is also required that unevenness in the outer periphery of the lens be suppressed. According to the lens manufacturing method of the present invention, it is possible to manufacture lenses having the above-mentioned characteristics.

[0010] It should be noted that in this specification, "~" is used to encompass the values ​​described before and after it as the lower limit and upper limit values.

[0011] Additionally, in this specification, the refractive index is the refractive index below the e-line.

[0012] <Lens Manufacturing Method>

[0013] The lens manufacturing method of the present invention includes the above-described step 1 and step 2.

[0014] The steps for each process are explained below.

[0015] [Process 1]

[0016] The lens manufacturing method of the present invention includes step 1.

[0017] Step 1 is a process of pre-wetting the substrate containing the plastic lens using a pre-wetting solution.

[0018] After explaining the substrate and pre-wetting liquid, the implementation method of step 1 will be explained.

[0019] (Substrate)

[0020] The substrate used in process 1 contains plastic lenses.

[0021] There are no particular restrictions on the substrate as long as it contains a plastic lens, and it can also contain other layers. For example, the substrate used in step 1 can be a substrate with other layers formed on the plastic lens.

[0022] Other layers mentioned above could include, for example, the base coat layer.

[0023] The following describes the base coatings that may be included in plastic lenses and substrates.

[0024] There are no particular restrictions on the type of plastic lens used; conventionally known plastic lenses can be used. Examples of preferred plastic lenses include those for eyeglasses.

[0025] There are no particular restrictions on the types of plastic lenses. For example, when plastic lenses are used in eyeglasses, examples include finished lenses that have undergone optical finishing on both the convex and concave surfaces and are shaped according to the desired power; semi-finished lenses that have undergone finishing on only the convex surface (spherical, rotationally symmetric aspherical, progressive, etc.); and lenses obtained by processing and grinding the concave surface of a semi-finished lens according to the wearer's prescription.

[0026] There are no particular limitations on the types of plastics (so-called resins) contained in plastic lenses. Examples include (meth)acrylate resins, thiourethane resins, allyl resins, cyclic sulfur resins, polycarbonate, urethane resins, polyesters, polystyrene, polyethersulfone, poly4-methyl-1-pentene, and diethylene glycol dielyl carbonate resin (CR-39). Among these, thiourethane resins, cyclic sulfur resins, and diethylene glycol dielyl carbonate resins are preferred.

[0027] It should be noted that thiocarbamate resins can be obtained from polyisocyanate compounds and polythiol compounds.

[0028] As a polyisocyanate compound, at least one selected from isophthalic diisocyanate, a mixture of 2,5-bis(isocyanate methyl)-bicyclo[2,2,1]heptane and 2,6-bis(isocyanate methyl)-bicyclo[2,2,1]heptane, isophorone diisocyanate, hexamethylene diisocyanate and toluene diisocyanate is preferred.

[0029] As a polythiol compound, at least one selected from pentaerythritol tetra(3-mercaptopropionic acid) ester, 1,2-bis[(2-mercaptoethyl)thio]-3-mercaptopropane, and a mixture of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane and 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane is preferred.

[0030] Cyclosulfide resins can be obtained by ring-opening polymerization of monomers having cyclosulfide groups (also known as epithio groups) or mixed monomers containing such monomers. As monomers having cyclosulfide groups, at least one selected from bis(2,3-cyclothiopropyl) sulfide and bis(2,3-cyclothiopropyl) disulfide is preferred.

[0031] There are no particular restrictions on the thickness of plastic lenses, but from an operational perspective, they are usually between 1mm and 30mm.

[0032] Furthermore, there are no particular restrictions on the size of plastic lenses, which are mostly between 1 and 200 mm. When plastic lenses are used for eyeglasses, their size is usually between 50 and 100 mm.

[0033] There are no particular restrictions on the refractive index of plastic lenses, but in most cases it is above 1.50, preferably 1.60 to 1.80, and more preferably 1.60 to 1.74.

[0034] Plastic lenses are preferably translucent and can be either transparent or opaque. Additionally, plastic lenses can also be colored.

[0035] Plastic lenses may contain additives such as blueing agents, light stabilizers, ultraviolet absorbers, and antioxidants.

[0036] The substrate may include a base coating. The base coating improves the adhesion of the hard coating formed in step 2 described later to the plastic lens, thereby imparting impact resistance to the resulting lens.

[0037] As described below, the base coating may be formed on only one side of the plastic lens or on both sides of the plastic lens.

[0038] There are no particular restrictions on the materials used to form the base coating; well-known materials can be used, such as resins. There are no particular restrictions on the types of resins used; examples include polyurethane resins, polyester resins, and polyvinyl alcohol, with polyurethane resins being preferred.

[0039] The base coating may also contain other components besides the aforementioned resin.

[0040] Other components may include, for example, oxide particles or composite oxide particles of at least one metal selected from Si, Al, Sn, Sb, Ta, Ce, La, Fe, Zn, W, Zr, In and Ti, hydrolyzable silicon compounds and / or their hydrolytic condensates, and surfactants.

[0041] There are no particular limitations on the method of forming the base coating. Well-known methods can be used, such as applying a base coating forming composition containing a specified resin onto a plastic lens and performing a curing treatment as needed to form the base coating.

[0042] There are no particular limitations on the method of applying the composition for forming the primer coating, for example, the method illustrated in the method of applying the composition for forming the hard coating onto the substrate described later.

[0043] There is no particular limitation on the thickness of the base coating, but it is preferably 0.3 to 2 μm.

[0044] (Pre-wetting solution)

[0045] The pre-wetting liquid used in step 1 contains a first solvent with a boiling point of 60 to 100°C and a second solvent with a boiling point of 150 to 210°C, and the content of the second solvent relative to the combined mass of the first solvent and the second solvent is greater than 20% by mass.

[0046] In addition, the hard coating forming composition described later contains a second solvent.

[0047] It is believed that when the pre-wetting liquid contains a second solvent, the second solvent is likely to remain on the surface of the substrate in step 2 described later. Furthermore, it exhibits excellent compatibility with the hard coating forming composition. Therefore, when the hard coating forming composition is applied, it easily and uniformly wets and spreads relative to the substrate surface. When the hard coating forming composition uniformly wets and spreads relative to the substrate surface, a hard coating can be uniformly formed at the center of the resulting lens, resulting in the suppression of unevenness.

[0048] It is believed that when the pre-wetting liquid contains the first solvent, the pre-wetting liquid has moderate volatility. Generally, it can be said that the film thickness of the pre-wetting liquid coating formed by the pre-wetting treatment tends to be thicker near the outer periphery of the substrate compared to the center. Here, it is believed that by ensuring the pre-wetting liquid has moderate volatility, the film thickness of the pre-wetting liquid coating at the outer periphery of the substrate will not become excessive, and when applying the hard coating forming composition in step 2, the amount of the hard coating forming composition coating at the outer periphery of the substrate can be adjusted to an appropriate level. It is believed that the result is that the unevenness of the outer periphery of the obtained lens is suppressed.

[0049] In the pre-wetting solution, the combined amount of the first solvent and the second solvent is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, relative to the total mass of the pre-wetting solution. In the pre-wetting solution, the combined amount of the first solvent and the second solvent can be 100% by mass, relative to the total mass of the pre-wetting solution. That is, the pre-wetting solution can be composed of the first solvent and the second solvent.

[0050] It should be noted that, in this invention, boiling point refers to one atmosphere (1.01325 × 10⁻⁶). 5 The boiling point is the temperature at which the saturated vapor pressure of a monomer in its liquid state is equal to that of one atmosphere. The boiling point can be determined at one atmosphere by measuring the saturated vapor pressure, or by referring to literature values.

[0051] The boiling point of the first solvent contained in the pre-wetting solution is 60-100°C, preferably 60-80°C, and more preferably 60-70°C.

[0052] The first solvent is not particularly limited as long as it falls within the aforementioned boiling point range, but an alcohol solvent is preferred. It should be noted that an alcohol solvent refers to a solvent composed of a compound having one or more hydroxyl groups within its molecule. Preferably, the alcohol solvent contains only one hydroxyl group. The alcohol solvent as the first solvent preferably has 4 or fewer carbon atoms, more preferably 3 or fewer, and even more preferably 2 or fewer. The lower limit for the number of carbon atoms in the alcohol solvent as the first solvent is preferably 1 or more.

[0053] 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), with methanol or ethanol being more preferred, and methanol being even more preferred. It should be noted that the temperatures in parentheses following each of the above compounds indicate the boiling points of the compounds in the aforementioned states.

[0054] It should be noted that the first solvent can be a solvent composed of only a single compound, or a solvent composed of two or more compounds. It should also be noted that when using a solvent composed of two or more compounds as the first solvent, the solvent composed of individual monomers of each compound must meet the aforementioned boiling point requirements.

[0055] The second solvent contained in the pre-wetting solution has a boiling point of 150–210°C, preferably 160–190°C, and more preferably 170–180°C.

[0056] The second solvent is not particularly limited as long as it is within the aforementioned boiling point range, but an alcohol solvent is preferred. Preferably, the alcohol solvent contains one hydroxyl group within its molecule.

[0057] 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.

[0058] Furthermore, the alcohol solvent used as the second solvent is preferably a glycol ether solvent. A glycol ether solvent is a solvent composed of compounds containing one or more ether bonds (-O-) that bond carbon atoms together and one or more hydroxyl groups. The number of ether bonds in the glycol ether solvent is preferably 2 or less, more preferably 1.

[0059] 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. It should be noted that the temperatures in parentheses following each of the above compounds indicate the boiling points of the compounds in the aforementioned states.

[0060] It should be noted that the above-mentioned 2-butoxyethanol is also known as butyl cellosolve.

[0061] It should be noted that the second solvent can be a solvent composed of only a single compound, or a solvent composed of two or more compounds. It should also be noted that when using a solvent composed of two or more compounds as the second solvent, the solvent composed of individual monomers of each compound must meet the aforementioned boiling point requirements.

[0062] It is also preferable that both the first solvent and the second solvent are alcohol solvents.

[0063] In addition, in the pre-wetting solution, the content of the second solvent relative to the combined amount of the first solvent and the second solvent is greater than 20% by mass.

[0064] From the viewpoint of further suppressing the peripheral unevenness of the obtained lens, the content of the second solvent relative to the combined amount of the first solvent and the second solvent is preferably 50% by mass or less, preferably less than 40% by mass, and more preferably less than 30% by mass.

[0065] It should be noted that the prewetting solution may also contain components other than the first and second solvents mentioned above (other components).

[0066] (Pre-wetting treatment)

[0067] The pre-wetting treatment is performed on the substrate containing the plastic lens using the aforementioned pre-wetting liquid.

[0068] There are no particular limitations on the pre-wetting treatment as long as a coating composed of a pre-wetting liquid is formed on at least one surface of the substrate. Examples of pre-wetting treatment methods include dip coating, spin coating, spray coating, inkjet coating, and flow coating. Spin coating is preferred from the perspective of achieving more uniform pre-wetting treatment.

[0069] When pre-wetting is performed by spin coating, for example, the pre-wetting process can be performed by the following steps.

[0070] First, the substrate is placed in a spin coater equipped with a stand that can hold and rotate the substrate. While the substrate is not rotating or is rotating at a low speed (200–400 rpm), a pre-wetting liquid is supplied to the surface of the substrate. The pre-wetting liquid can be supplied only to the vicinity of the substrate's rotation center, or in a vortex pattern centered on the substrate's rotation center, or it can be supplied to the entire surface of the substrate.

[0071] Next, the substrate supplied with the pre-wetting liquid is rotated, causing the pre-wetting liquid to spread across the entire surface of the substrate. The rotation speed of the substrate can be adjusted appropriately, for example, from 700 to 1500 rpm.

[0072] There is no particular limitation on the temperature of the substrate during pre-wetting treatment, but from the viewpoint of easily obtaining the effects of pre-wetting treatment, it is preferable to be below 50°C, more preferably below 40°C. The lower limit of the substrate temperature can be, for example, 10°C or higher, 25°C or higher, or 30°C or higher. It is believed that since the pre-wetting liquid used in the pre-wetting treatment of the present invention has the configuration described above, even if the substrate temperature reaches 30°C or higher through step 3 described later, the hard coating forming composition can easily and uniformly wet and spread relative to the substrate surface under the above mechanism, and unevenness of the outer periphery of the resulting lens is also suppressed.

[0073] [Process 2]

[0074] The lens manufacturing method of the present invention includes step 2.

[0075] Step 2 is a step of forming a hard coating on a pre-wetted substrate using a hard coating forming composition containing a second solvent.

[0076] After describing the composition for forming the hard coating, the method of carrying out step 2 will be described.

[0077] (Composition for forming a hard coating)

[0078] The hard coating composition used in step 2 contains the aforementioned second solvent.

[0079] The hard coating forming composition contains, in addition to the second solvent described above, components capable of forming a hard coating. The components that may be contained in the hard coating forming composition will be described below.

[0080] It should be noted that, in the following, all solid components in the composition for forming a hard coating refer to components that can constitute a hard coating; solvents such as a second solvent are not included in the solid components. Furthermore, even if a component is liquid, as long as it constitutes a hard coating, it is counted as a solid component.

[0081] The composition for forming a hard coating preferably contains a sesquioxane compound.

[0082] Silsesquioxane compounds are typically silane compounds with the basic skeleton shown in formula (D), obtained by hydrolyzing trifunctional silane compounds such as alkoxysilanes, chlorosilanes, and silanols. In addition to the irregular morphology known as the random structure, known structures of silsesquioxane compounds include trapezoidal structures, cage-like (fully condensed cage-like) structures, and incomplete cage-like structures (partially cracked cage-like structures, i.e., structures after the loss of some silicon atoms from the cage-like structure, or structures after the breakage of some silicon-oxygen bonds in the cage-like structure).

[0083] In the following formula (D), R d It represents an organic group.

[0084] Formula (D) R d -SiO 3 / 2

[0085] The structure of the silsesquioxane compound contained in the hard coating forming composition can be any one of the above-mentioned random structure, trapezoidal structure, cage structure and incomplete cage structure, or it can be a mixture of two or more structures.

[0086] Silsesquioxane compounds preferably have polymerizable groups. As polymerizable groups, free radical polymerizable groups or cationic polymerizable groups are preferred.

[0087] As a free radical polymerizable group contained in a silsesquioxane compound, a group having an olefinically unsaturated bond is preferred. Examples of groups having an olefinically unsaturated bond include (meth)acryloyl, styryl, and vinyl groups.

[0088] When the silsesquioxane compound contains free radical polymerizable groups, there is no particular limitation on the equivalent of free radical polymerizable groups contained in the silsesquioxane compound, but from the perspective of better hardness of the hard coating, it is preferred to be 30 to 500 g / eq., more preferably 30 to 150 g / eq.

[0089] Silsesquioxane compounds with free radical polymerizable groups can be synthesized by known methods or commercially available products.

[0090] There are no particular limitations on the cationic polymerizable groups contained in sesquioxane compounds; for example, oxobutyl and epoxy groups can be listed.

[0091] The above-mentioned oxocyclic butyl group is represented by the following formula (2). R 2 It represents a hydrogen atom or an alkyl group (e.g., methyl, ethyl, and propyl). Indicates the bonding location.

[0092]

[0093] The epoxy group mentioned above is represented by the following formula (3). R 1 It represents a hydrogen atom or an alkyl group (e.g., methyl, ethyl, and propyl). Indicates the bonding location.

[0094]

[0095] The aforementioned specific silsesquioxanes can be synthesized using known methods or commercially available products. Examples of commercially available products include OX-SQ TX-100, OX-SQ SI-20, OX-SQ HDX, and OX-SQ ME-20 manufactured by Toa Synthetic Co., Ltd.

[0096] The content of the silsesquioxane compound having polymerizable groups in the hard coating forming composition is not particularly limited, but is preferably 10 to 60% by mass, more preferably 20 to 55% by mass, relative to the total solid content in the hard coating forming composition.

[0097] The composition for forming a hard coating may contain metal oxide particles.

[0098] There are no particular limitations on the types of metal oxide particles; well-known metal oxide particles can be listed. Examples of metal oxide particles include particles of oxides of at least one metal selected from Si, Al, Sn, Sb, Ta, Ce, La, Fe, Zn, W, Zr, In, and Ti. From an operational perspective, the preferred metal oxide particles are particles containing Si oxides (silicon oxide particles), particles containing Sn oxides (tin oxide particles), particles containing Zr oxides (zirconia particles), or particles containing Ti oxides (titanium oxide particles).

[0099] It should be noted that metal oxide particles may contain only one type of metal (metal atom) as exemplified above, or they may contain two or more types of metal (metal atom).

[0100] In addition, Si is sometimes classified as a half-metal, but in this specification, Si is included in the metal category.

[0101] The average particle size of the metal oxide particles is not particularly limited, but is preferably 1 to 200 nm, more preferably 5 to 30 nm. Within the above range, the dispersion stability of the metal oxide particles in the hard coating forming composition is better, and the whitening of the cured product can be further suppressed.

[0102] It should be noted that the above average particle size was obtained by measuring the diameters of more than 100 metal oxide particles using a transmission electron microscope and then arithmetically averaging them. It should also be noted that in cases where the metal oxide particles are not perfectly spherical, the major axis is used as the diameter.

[0103] Various functional groups can be introduced onto the surface of metal oxide particles as needed.

[0104] The content of metal oxide particles in the hard coating forming composition is not particularly limited, but is preferably 10 to 70% by mass, more preferably 25 to 55% by mass, relative to the total solid content in the hard coating forming composition.

[0105] The composition for forming a hard coating may contain polymerizable monomers. Silsesquioxane compounds having the aforementioned polymerizable groups are not included in the aforementioned polymerizable monomers.

[0106] Polymerizable monomers are compounds that have polymerizable groups. Examples of polymerizable monomers include compounds with free radical polymerizable groups and compounds with cationic polymerizable groups. Preferably, polymerizable monomers have 2 to 6 polymerizable groups, more preferably 2 to 3.

[0107] As for the compounds with free radical polymerizable groups mentioned above, (meth)acrylate compounds are preferred. It should be noted that (meth)acrylate compounds represent the concept of compounds containing methacryloyl groups and compounds containing acryloyl groups.

[0108] (Meth)acrylate compounds are preferably polyfunctional (meth)acrylate compounds having two or more free radical polymerizable groups (methacryloyl or acryloyl) within the molecule, and the preferred number of polymerizable groups is as described above.

[0109] In addition, the above-mentioned (meth)acrylate compounds may also be compounds having groups selected from the group consisting of phosphate groups and sulfonic acid groups.

[0110] As a polyfunctional (meth)acrylate, the compound shown in formula (E) is preferred.

[0111] Equation (E) CH2=CR e1 -CO-L e1 -CO-CR e2 =CH2

[0112] R e1 and R e2 Each can be used independently to represent a hydrogen atom or a methyl group.

[0113] L e1 This refers to a divalent hydrocarbon group that may contain heteroatoms (e.g., oxygen, nitrogen, or sulfur atoms). The number of carbon atoms in the divalent hydrocarbon group is not particularly limited, but is preferably 1 to 10. Examples of divalent hydrocarbon groups that may contain heteroatoms include alkylene, alkenyl, ynylene, aryl, and combinations thereof; alkylene groups that may contain heteroatoms are preferred.

[0114] Preferably, it is an alkylene group containing an oxygen atom, and more preferably it is composed of -O-(L e2 -O) r - indicates a group. It should be noted that L... e2 The symbol represents an alkylene group (preferably with 1 to 3 carbon atoms). r represents an integer of 1 or more, preferably an integer of 1 to 10, and more preferably an integer of 2 to 5.

[0115] The above-mentioned (meth)acrylate compounds can be used alone or in combination of two or more.

[0116] As for the above-mentioned compounds having cationic polymerizable groups, epoxy compounds having epoxy groups are preferred. It should be noted that the epoxy group is the group shown in formula (3) above.

[0117] The epoxy compound is preferably a polyfunctional epoxy compound having two or more epoxy groups within the molecule, and the preferred number of polymerizable groups is as described above.

[0118] There are no particular limitations on the types of multifunctional epoxy compounds; well-known multifunctional epoxy compounds can be listed. Examples of multifunctional epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, phenolic varnish type epoxy compounds, cresol phenolic varnish type epoxy compounds, and aliphatic glycidyl ether type epoxy compounds.

[0119] The above-mentioned epoxy compounds can be used alone or in combination of two or more.

[0120] The composition for forming a hard coating may contain at least one selected from the group consisting of hydrolyzable silicon compounds, their hydrolysis products, and their hydrolysis condensates (hereinafter also referred to as "hydrolyzable silicon compounds"). It should be noted that hydrolyzable silicon compounds refer to compounds with hydrolyzable groups bonded to silicon atoms.

[0121] The preferred hydrolyzable silicon compound is the compound represented by formula (H).

[0122] Formula (H) R h1 -L h -Si(R h2 ) s (R h3 ) 3-s

[0123] R h1 It represents an epoxy group.

[0124] The definition of an epoxy group is as described above.

[0125] L h This indicates a divalent hydrocarbon group that may contain heteroatoms. The number of carbon atoms in the hydrocarbon group is not particularly limited, but is preferably 1 to 10. Examples of divalent hydrocarbon groups include alkylene, alkenylene, ynylene, arylene, and combinations thereof; alkylene groups that may contain heteroatoms are preferred.

[0126] R h2 This refers to a hydrolyzable group. A hydrolyzable group is a group directly bonded to Si (silicon atoms) that can undergo hydrolysis and / or condensation reactions. Examples of hydrolyzable groups include alkoxy, hydroxyl, halogen, acyloxy, alkenyloxy, and isocyanate groups.

[0127] R h3 Indicates an alkyl group. Derived from R h3 The alkyl group represented preferably has 1 to 10 carbon atoms.

[0128] s represents an integer from 1 to 3. s is preferably 3.

[0129] Hydrolysis products of hydrolyzable silicon compounds refer to compounds obtained by hydrolyzing the hydrolyzable groups in the hydrolyzable silicon compound. It should be noted that the aforementioned hydrolysis products can be compounds in which all hydrolyzable groups have been hydrolyzed (completely hydrolyzed products) or compounds in which only a portion of the hydrolyzable groups have been hydrolyzed (partially hydrolyzed products). In other words, the aforementioned hydrolysis products can be completely hydrolyzed products, partially hydrolyzed products, or mixtures thereof.

[0130] Furthermore, hydrolysis condensates of hydrolyzable silicon compounds refer to compounds obtained by condensing the hydrolysis products after hydrolysis of the hydrolyzable groups in the hydrolyzable silicon compound. It should be noted that the aforementioned hydrolysis condensates can be compounds in which all hydrolyzable groups have undergone hydrolysis and all hydrolysis products have undergone condensation (complete hydrolysis condensates), or compounds in which some hydrolyzable groups have undergone hydrolysis and some hydrolysis products have undergone condensation (partial hydrolysis condensates). In other words, the aforementioned hydrolysis condensates can be complete hydrolysis condensates, partial hydrolysis condensates, or mixtures thereof.

[0131] When the hard coating forming composition contains hydrolyzable silicon compounds, the content of the hydrolyzable silicon compounds is not particularly limited, but is preferably 0.5 to 30% by mass, more preferably 1 to 10% by mass, relative to the total solid content of the hard coating forming composition.

[0132] The composition for forming a hard coating may contain a free radical polymerization initiator. Examples of free radical polymerization initiators include photoradical polymerization initiators and thermal free radical polymerization initiators.

[0133] The composition for forming a hard coating may contain a cationic polymerization initiator. Examples of cationic polymerization initiators include photocationic polymerization initiators and thermal cationic polymerization initiators.

[0134] The composition for forming a hard coating can contain various additives as needed, such as ultraviolet absorbers, surfactants, anti-aging agents, coating conditioners, light stabilizers, antioxidants, anti-coloring agents, dyes, fillers, and internal release agents.

[0135] The composition for forming a hard coating contains the second solvent described above, or it may contain solvents other than the second solvent described above.

[0136] For example, the composition for forming a hard coating may contain a first solvent. The preferred manner of the first solvent is as described above. The first solvent contained in the composition for forming a hard coating may be two or more.

[0137] The content of the solvent containing the second solvent in the hard coating forming composition is preferably 10 to 90% by mass relative to the total mass of the hard coating forming composition, more preferably 10 to 50% by mass.

[0138] Furthermore, the content of the second solvent in the hard coating forming composition is preferably 10 to 60% by mass relative to the total content of solvents contained in the hard coating forming composition, more preferably 10 to 40% by mass.

[0139] Furthermore, the content of the first solvent in the hard coating forming composition is preferably 40 to 90% by mass relative to the total content of solvents contained in the hard coating forming composition, more preferably 60 to 85% by mass.

[0140] The content of all solid components in the hard coating forming composition is preferably 10 to 90% by mass relative to the total mass of the hard coating forming composition, more preferably 40 to 80% by mass.

[0141] The viscosity of the hard coating forming composition can be appropriately adjusted. From the perspective of the coatability of the hard coating 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. There is no particular limitation on the lower limit of the viscosity of the hard coating forming composition, but it can be 1 mPa·s or more, and in most cases it is 5 mPa·s or more.

[0142] It should be noted that, according to the lens manufacturing method of the present invention, even when the viscosity of the hard coating forming composition is 10 mPa·s or higher, the hard coating forming composition can uniformly wet and spread relative to the substrate surface, and can uniformly form a hard coating.

[0143] It should be noted that, in this invention, the viscosity of the above-mentioned hard coating forming composition is the value at 25°C.

[0144] The composition for forming a hard coating can be prepared by mixing the components described above. There are no particular limitations on the mixing method, and known methods can be used.

[0145] Here, when the hard coating forming composition contains silsesquioxane and metal oxide particles having cationic polymerizable groups, it is preferable to obtain the hard coating forming composition by the following steps from the viewpoint of suppressing the change in viscosity over time during storage.

[0146] First, as step A, a mixture containing silsesquioxane and metal oxide particles having cationic polymerizable groups is heat-treated at a temperature exceeding 60°C. Next, as step B, the mixture obtained in step A is mixed with a cationic polymerization initiator to obtain a composition for forming a hard coating.

[0147] 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.

[0148] In addition, there is no particular limit to the upper limit of the heating temperature, but it is preferably below 200°C.

[0149] It should be noted that the heating temperature mentioned above refers to the set temperature of the heating device (hot plate, etc.) used to heat the mixture.

[0150] (Formation of a hard coating)

[0151] In step 2, a hard coating is formed using the above-mentioned hard coating forming composition.

[0152] In step 2, there are no particular limitations on the method as long as the above-mentioned hard coating forming composition is used to form a hard coating on a substrate that has undergone pre-wetting treatment. Preferably, the hard coating is formed by applying the hard coating forming composition to a substrate that has undergone pre-wetting treatment, forming a coating film composed of the hard coating forming composition, and curing the coating film of the hard coating forming composition.

[0153] There are no particular limitations on the method for applying the composition for forming a hard coating and for forming the film of the composition for forming a hard coating; it can be carried out by the same method as the pre-wetting treatment. In the above methods, the application of the composition for forming a hard coating and the formation of the film of the composition for forming a hard coating are preferably carried out by spin coating.

[0154] The preferred method for spin coating is as described above.

[0155] The curing treatment of the coating film of the hard coating forming composition can be appropriately selected according to the components contained in the hard coating forming composition.

[0156] Examples of curing processes include heat treatment and light irradiation treatment.

[0157] The temperature of the heat treatment can be adjusted appropriately. For example, the preferred heating temperature is 30 to 100°C, and the preferred heating time is 5 to 360 minutes.

[0158] There are no particular restrictions on the type of light used for illumination; for example, ultraviolet light and visible light can be included. High-pressure mercury lamps can be used as a light source, for example.

[0159] There is no particular limitation on the cumulative light intensity during irradiation, but considering productivity and coating curability, a concentration of 100–3000 mJ / cm is preferred. 2 More preferably, it is 100–1500 mJ / cm 2 .

[0160] The curing process can be performed after the coating film of the composition for forming a hard coating layer has been dried. Heat treatment can be an example of a drying process. The heat treatment in the curing process can also serve as a drying process.

[0161] The thickness of the formed hard coating 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. It should be noted that the upper limit of the film thickness can be set, for example, to 30 μm or less.

[0162] The above film thickness is the average film thickness. As a method of measurement, the film thickness of any 5 points of the hard coating is measured and the film thickness is calculated by arithmetic averaging.

[0163] The coating of the hard coating composition is applied to a substrate that has undergone the pre-wetting treatment described above, preferably while a coating film containing the pre-wetting liquid formed during the pre-wetting treatment remains. For example, it is preferable not to perform any treatment to remove the pre-wetting liquid, such as drying, between the pre-wetting treatment and the application of the hard coating composition.

[0164] Furthermore, the coating of the hard coating composition is preferably performed within 1 to 10 seconds after the above-mentioned pre-wetting treatment without drying.

[0165] [Process 3]

[0166] The lens manufacturing method of the present invention may further include a step 3 of drying the substrate before step 1 described above.

[0167] Drying processes can preferably include processes that involve heating the substrate.

[0168] When a drying process such as step 3 is performed, the substrate is prone to heat generation due to the drying process. Compared with the case where step 1 is not performed, it is possible to obtain more significant effects in terms of excellent wetting and spreading properties when applying the composition for forming a hard coating, and to suppress the unevenness of the outer periphery of the resulting lens.

[0169] There are no particular restrictions on the object to be dried, as long as it is a substrate, and there are no restrictions on the purpose of the drying process.

[0170] For example, the drying process can be a process aimed at removing solvents used for cleaning the substrate, or it can be a process aimed at removing solvents contained in the coating film formed on the plastic lens. As an example of the coating film formed on the aforementioned plastic lens, a coating film formed by a primer layer forming composition can be cited.

[0171] In addition, the lens manufacturing method of the present invention may include the steps of forming the lens configuration described later.

[0172] Lenses

[0173] The lens obtained by the lens manufacturing method of the present invention will be described below.

[0174] Figure 1 This is an example of a lens obtained by the lens manufacturing method of the present invention.

[0175] Figure 1 The lens 20 shown has, in sequence, a plastic lens 10, a base coating 12, a hard coating 14, an anti-reflective film 16, and a water- and oil-repellent layer 18.

[0176] exist Figure 1 In the lens 20 shown, a base coating 12, a hard coating 14, an anti-reflective film 16, and a water- and oil-repellent layer 18 are sequentially formed on one side of the plastic lens 10. Figure 1 Alternatively, a base coating, a hard coating, an anti-reflective film, and a water- and oil-repellent layer can be sequentially formed on the surface of the plastic lens 10 opposite to the base coating 12.

[0177] In addition, Figure 1 In the lens 20 shown, any one or more of the base coating 12, anti-reflective film 16, and water- and oil-repellent layer 18 may be omitted.

[0178] The plastic lens 10, the base coating 12, and the hard coating 14 are as described above, and the preferred embodiment is also as described above. Hereinafter, the anti-reflective film and the water- and oil-repellent layer that can be present in the lens obtained by the lens manufacturing method of the present invention (hereinafter, also simply referred to as "the obtained lens") will be described.

[0179] [Anti-reflective film]

[0180] The resulting lens may have an anti-reflective coating. The anti-reflective coating is preferably disposed on the side of the hard coating opposite to the plastic lens.

[0181] An antireflective coating is a layer that prevents the reflection of incident light. Specifically, it exhibits low reflectivity across the entire visible light region of 380–780 nm (wide-band low reflectivity).

[0182] There are no particular restrictions on the structure of the anti-reflective film; it can be a single-layer structure or a multi-layer structure.

[0183] Inorganic antireflective films are preferred as antireflective films. Inorganic antireflective films refer to antireflective films composed of inorganic compounds.

[0184] 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. It should be noted that materials constituting the high-refractive-index layers can include, for example, oxides of titanium, zirconium, aluminum, niobium, tantalum, or lanthanum. Materials constituting the low-refractive-index layers can include, for example, silicon dioxide oxide.

[0185] There are no particular restrictions on the manufacturing methods of antireflective films. For example, dry methods such as vacuum evaporation, sputtering, ion plating, ion beam assisted deposition, and CVD can be listed.

[0186] [Water- and oil-repellent layer]

[0187] The resulting lens may include a water- and oil-repellent layer. The water- and oil-repellent layer is preferably disposed on the outermost layer of the lens.

[0188] The water- and oil-repellent coating reduces the surface energy of the lens, improves its anti-fouling function, and enhances the smoothness of the lens surface, resulting in improved wear resistance.

[0189] The water- and oil-repellent layer is preferably applied when the resulting lens is an eyeglass lens.

[0190] There are no particular limitations on the materials constituting the water- and oil-repellent layer. Examples include fluorinated compounds (compounds containing fluorine atoms) and silicon compounds (compounds containing silicon atoms). Among these, from the perspective of better water and oil repellency, the water- and oil-repellent layer preferably contains a fluorinated compound, and more preferably contains at least one selected from the group consisting of an organosilicon compound containing a fluorinated substituted alkyl group, its hydrolysis product, and its hydrolysis condensate.

[0191] It should be noted that the materials constituting the water-repellent and oil-repellent layer can be used alone or in combination of two or more materials.

[0192] Organosilicon compounds containing fluorinated alkyl groups refer to organosilicon compounds containing alkyl groups in which some or all of the hydrogen atoms are replaced by fluorine atoms, and which have hydrolyzable groups.

[0193] Here, hydrolyzable groups refer to groups directly bonded to silicon atoms that can undergo hydrolysis and condensation reactions. Examples include alkoxy groups, halogen groups, acyloxy groups, alkenyloxy groups, and isocyanate groups. It should be noted that when two or more hydrolyzable groups are directly bonded to a single silicon atom, they can be the same or different.

[0194] Hydrolysis products of organosilicon compounds containing fluorinated alkyl groups refer to compounds obtained by hydrolyzing the hydrolyzable groups in organosilicon compounds containing fluorinated alkyl groups. It should be noted that the aforementioned hydrolysis products can be compounds in which all hydrolyzable groups have been hydrolyzed (completely hydrolyzed products) or compounds in which only a portion of the hydrolyzable groups have been hydrolyzed (partially hydrolyzed products). In other words, the aforementioned hydrolysis products can be completely hydrolyzed products, partially hydrolyzed products, or mixtures thereof.

[0195] Hydrolysis condensates of organosilicon compounds containing fluorinated alkyl groups refer to compounds obtained by condensing the hydrolysis products after hydrolysis of the hydrolyzable groups in the organosilicon compound containing fluorinated alkyl groups. It should be noted that the aforementioned hydrolysis condensates can be compounds in which all hydrolyzable groups have undergone hydrolysis and all hydrolysis products have undergone condensation (complete hydrolysis condensates), or compounds in which some hydrolyzable groups have undergone hydrolysis and some hydrolysis products have undergone condensation (partial hydrolysis condensates). In other words, the aforementioned hydrolysis condensates can be complete hydrolysis condensates, partial hydrolysis condensates, or mixtures thereof.

[0196] There is no particular limitation on the thickness of the water- and oil-repellent layer of the obtained lens, but it is preferably 5 to 35 nm.

[0197] There are no particular limitations on the method for forming a water- and oil-repellent layer; it can be chosen arbitrarily based on the materials used, desired performance, or thickness. For example, methods such as coating a water- and oil-repellent layer forming composition containing an organosilicon compound with fluorinated alkyl groups onto a substrate and performing a curing treatment as needed, as well as dry methods, can be listed.

[0198] Examples of coating methods include dip coating, roller coating, bar coating, spin coating, spray coating, mold coating, and gravure coating.

[0199] Examples of curing processes include light irradiation, heat treatment, and steam contact treatment. Steam contact treatment may include, for example, contact with air at a humidity level controlled to 50–90% RH. These curing processes can be combined.

[0200] Dry methods can be exemplified by, for example, the same methods used for the antireflective films described above.

[0201] <Applications>

[0202] The lens obtained by the lens manufacturing method of the present invention is suitable for various lens applications because it can uniformly form a hard coating in the central part of the lens and suppress unevenness in the outer periphery of the lens. Among these applications, it is suitable for use as an eyeglass lens.

[0203] Example

[0204] The above-described methods will be described in more detail below through examples and comparative examples, but the present invention is not limited to these examples.

[0205] <Example 1>

[0206] [Preparation of pre-wetting solution]

[0207] Methanol and 2-butoxyethanol were mixed at a mass ratio of 75% by mass and 25% by mass, respectively, to obtain the prewetting solution used in Example 1.

[0208] [Preparation of compositions for hard coating formation]

[0209] In a glass container equipped with a stir bar, a cationic cured silsesquioxane (manufactured by Toa Synthetic Co., Ltd.: OX-SQ TX-100) (27.13 g) as (A) silsesquioxane and colloidal silica (manufactured by Nichih Catalyst Chemical Co., Ltd.: OSCAL-1432E, isopropanol dispersion, solid content 30% by mass) (90.45 g) as (B) metal oxide particles were added to form a mixture.

[0210] The resulting mixture was heated on a hot plate set to 160°C while being stirred for 6 hours. During this time, the glass container was sealed with a lid, and the solvent in the mixture was under reflux.

[0211] After heating, the resulting reaction solution was cooled to room temperature overnight. Then, 10.85 g of 2-butoxyethanol, used as a solvent for film formation, was added to the cooled reaction solution. Next, isopropanol was removed from the reaction solution by distillation under reduced pressure at 40°C for 2 hours.

[0212] Methanol (33.40 g) was added to the crude product to obtain liquid composition X1.

[0213] In a glass container equipped with a stir bar, add the liquid composition X1 (98.52 g) obtained in step 1 above, and SbF6 as a (D) cationic polymerization initiator. - A composition for forming a hard coating is obtained by mixing a sulfonium salt (manufactured by San-Aid SI-150L, ​​San-Aid Chemical Industry Co., Ltd.) (0.52 g), a hydroxyphenyl triazine ultraviolet absorber (manufactured by BASF Japan Co., Ltd.) (0.62 g) as an ultraviolet absorber (F), and a polyether-modified polysiloxane (manufactured by Toray Dow Corning Co., Ltd.) (DOWSIL L-7001) (0.33 g) as a surfactant (G).

[0214] [Preparation of the composition for forming the base coating]

[0215] In an aqueous urethane dispersion (Evafanol HA170, manufactured by Nichika Chemical Co., Ltd., with a solid content concentration of 37% by mass) (200 parts by mass), pure water (179 parts by mass), 501W ADDITIVE (manufactured by Dow Chemical) (1.1 parts by mass) and L7001 (manufactured by Dow Chemical) (1.1 parts by mass) as surfactants were added and stirred to obtain a composition for forming a base coating with a solid content concentration of 20.0% by mass.

[0216] [Formation of the base coating]

[0217] First, a plastic lens with a refractive index of 1.60 is prepared (manufactured by Nikon Essilor Corporation: NikonLite AS blank S-3.00D). The diameter of the plastic lens is 80mm.

[0218] The substrate is placed in a spin coater and rotated at 500 rpm for 2 seconds. During this rotation, 2.5 mL of a primer-forming composition is dropped onto the substrate from its outer periphery to its center. The substrate with the primer-forming composition dropped onto it is then rotated at 600 rpm for 10 seconds, followed by 5 seconds, and then at 2000 rpm for 3 seconds to perform a primer treatment. By performing the primer treatment, a coating film based on the primer-forming composition is formed on the substrate.

[0219] [Pre-wetting treatment]

[0220] The substrate for which the base coating has been formed through the above steps is pre-wetted.

[0221] First, the substrate is placed in a spin coater and rotated at 300 rpm for 2 seconds. During this rotation, 4 mL of the pre-wetting liquid used in Example 1 is dropped from the center to the outer periphery of the substrate. Then, the substrate with the pre-wetting liquid added is rotated at 1000 rpm for 1 second to perform a pre-wetting treatment. By performing the pre-wetting treatment, a coating film composed of the pre-wetting liquid is formed on the substrate.

[0222] It should be noted that the temperature of the substrate should be adjusted to 30-40℃ before the pre-wetting treatment.

[0223] [Formation of hard coating]

[0224] The surface of a substrate that has been pre-wetted through the above steps to form a pre-wetting liquid coating film is coated with the above-mentioned hard coating composition by spin coating to form a coating film of the hard coating composition.

[0225] The hard coating film is formed as follows: For a pre-wetting substrate, the substrate is rotated at 300 rpm for 4 seconds. During this rotation, 4 mL of the above-mentioned hard coating forming composition is added dropwise. Then, the substrate with the hard coating forming composition added is rotated at 300 rpm for 15 seconds, then rotated at 400 rpm for 5 seconds and then rotated for 1 second, then rotated at 700 rpm for 5 seconds and then rotated for 1 second, then rotated at 2000 rpm for 9.9 seconds and then rotated for 1 second, thereby forming the hard coating film.

[0226] After forming the coating film of the hard coating composition through the above steps, the substrate is heated at 80°C for 20 minutes, and then further heated at 100°C for 1 hour to form a cured film, thereby obtaining the lens. It should be noted that the thickness of the formed cured film is 15 μm.

[0227] [evaluate]

[0228] (Uniformity)

[0229] For a region with a radius of 30 mm from the center of the lens obtained through the above steps, observe the presence or absence of unevenness in the hard coating under fluorescent light and ultra-high pressure mercury lamp. Evaluate the uniformity of the formed hard coating according to the following evaluation criteria. In practice, evaluations of A to C are preferred.

[0230] A: No unevenness was observed under either ultra-high pressure mercury lamp or fluorescent lamp.

[0231] B: Slight heterogeneity was observed only under ultra-high pressure mercury lamps, and no heterogeneity was observed under fluorescent lamps.

[0232] C: Slight and deep heterogeneity were observed under ultra-high pressure mercury lamps, while slight heterogeneity was observed under fluorescent lamps, but no deep heterogeneity was observed.

[0233] D: Slight and deep heterogeneity were observed under both ultra-high pressure mercury lamp and fluorescent lamp.

[0234] (Peripheral unevenness)

[0235] For the area extending from a radius of 30 mm from the center of the lens obtained through the above steps to the outer periphery of the lens (a 10 mm area from the outer periphery towards the center of the lens), observe for any unevenness in the hard coating under fluorescent and ultra-high pressure mercury lamps. Evaluate the uniformity of the formed hard coating according to the following evaluation criteria. In practice, evaluations of A to C are preferred.

[0236] A: No heterogeneity was observed under either ultra-high pressure mercury lamp or fluorescent lamp.

[0237] B: Slight heterogeneity was observed under an ultra-high pressure mercury lamp, but no heterogeneity was observed under a fluorescent lamp.

[0238] C: Slight and deep heterogeneity were observed under ultra-high pressure mercury lamps, while slight heterogeneity was observed under fluorescent lamps, but no deep heterogeneity was observed.

[0239] D: Slight and deep heterogeneity were observed under both ultra-high pressure mercury lamp and fluorescent lamp.

[0240] <Comparative Examples 1 and Examples 2-5>

[0241] The composition of the pre-wetting liquid was changed as shown in the table below, except that the pre-wetting treatment and hard coating formation were performed in the same manner as in Example 1. However, for Comparative Example 1, the evaluation of peripheral unevenness was not performed.

[0242] Furthermore, the evaluation was conducted in the same manner as in Example 1. The evaluation results are shown in the table described below.

[0243] <Comparative Example 2>

[0244] The pre-wetting solution was changed to 100% methanol by mass, and the pre-wetting treatment and hard coating formation were performed in the same manner as in Example 1.

[0245] In addition, the uniformity of the hard coating was evaluated in the same manner as in Example 1. It should be noted that the evaluation of peripheral non-uniformity was not performed. The evaluation results are shown in the table described later.

[0246] <Comparative Example 3>

[0247] The pre-wetting solution was changed to 100% by mass of 2-butoxyethanol, and the pre-wetting treatment and hard coating formation were performed in the same manner as in Example 1.

[0248] Furthermore, the evaluation was conducted in the same manner as in Example 1. The evaluation results are shown in the table described below.

[0249] <Results>

[0250] The table shows the composition of the prewetting solution used in each embodiment and comparative example, as well as the evaluation results.

[0251] In Table 1, the "-" mark in the "Prewetting Solution" column indicates that the corresponding solvent was not used. Additionally, the content of each component in the "First Solvent" and "Second Solvent" columns is a percentage based on mass.

[0252] Additionally, in Table 1, the "-" mark in the "Evaluation" column indicates that no corresponding evaluation was conducted.

[0253]

[0254] Based on the results shown in the table, it was confirmed that when a pre-wetting liquid containing a first solvent with a specified boiling point and a second solvent with a specified boiling point, and the content of the second solvent relative to the combined amount of the first solvent and the second solvent is greater than 20% by mass, the uniformity of the hard coating as evaluated above (uniformity) is excellent, and the generation of peripheral unevenness is suppressed.

[0255] On the other hand, when the content of the second solvent in the pre-wetting liquid is less than 20% by mass or does not contain the second solvent relative to the combined amount of the first solvent and the second solvent, it is confirmed that the uniformity of the hard coating in the obtained lens, which is evaluated as above (uniformity), is poor.

[0256] Furthermore, peripheral unevenness was confirmed when the pre-wetting liquid did not contain the first solvent.

[0257] Based on the comparison of Examples 1-3 with Examples 4 and 5, it was confirmed that when the content of the second solvent relative to the combined amount of the first solvent and the second solvent is less than 40% by mass (preferably less than 30% by mass), the uniformity of the hard coating as evaluated above (uniformity) is better, and the generation of peripheral unevenness is further suppressed.

[0258] Symbol Explanation

[0259] 10 Plastic lenses

[0260] 12. Primer coating

[0261] 14 Hard coating

[0262] 16 Anti-reflective film

[0263] 18 Water and oil repellent layer

[0264] 20 lenses

Claims

1. A method for manufacturing a lens, comprising: Step 1, wherein a substrate containing a plastic lens is pre-wetted using a pre-wetting solution, the pre-wetting solution containing a first solvent with a boiling point of 60–100°C and a second solvent with a boiling point of 150–210°C, and the content of the second solvent relative to the total amount of the first solvent and the second solvent is greater than 20% by mass; and Step 2, wherein, for the substrate that has undergone the pre-wetting treatment, a hard coating is formed using a hard coating forming composition containing a second solvent.

2. The method for manufacturing a lens according to 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. The 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 manufacturing a lens according to any one of claims 1 to 4, wherein, The composition for forming the hard coating contains the first solvent.

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

7. The method for manufacturing a lens according to any one of claims 1 to 6, wherein, In the prewetting solution, the content of the second solvent relative to the total amount of the first solvent and the second solvent is greater than 20% by mass and less than 30% by mass.

8. The method for manufacturing a lens according to any one of claims 1 to 7, wherein, It also includes a step of drying the substrate prior to step 1.

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

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