Resin composition for water-repellent lens protective film and method for protecting water-repellent lens

Abstract

To provide a resin composition which can be uniformly coated even to an ultra water-repellent lens having high antifouling property, and enables formation of a protective film that is not peeled from the water-repellent lens upon the processing, has such adequate adhesiveness as to be easily peelable after processing, has such toughness as to prevent breakage of a cured film upon the peeling, and does not affect water-repellency of a base material after peeling.SOLUTION: A resin composition for a water-repellent lens protective film is provided, containing (A) polyfunctional (meth)acrylate having a weight average molecular weight of 250-30,000, (B) a polyfunctional thiol compound, (C) a photopolymerization initiator, and (D) a block copolymer which has a weight average molecular weight of 25,000 to 100,000 and is composed of a fluorine-based segment and a non-fluorine-based segment, wherein the resin composition for a water-repellent lens protective film includes, with respect to 100 pts.mass of the component (A), 0.5-30 pts.mass of the component (B), 0.1-25 pts.mass of the component (C), and 0.1-25 pts.mass of the component (D).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resin composition for a water-repellent lens protective film for protecting the surface of a water-repellent lens during peripheral processing of the lens, and also to a method for protecting a water-repellent lens in order to hold the lens in a processing device during peripheral processing of the lens. [Background technology]

[0002] The periphery of the eyeglass lens is processed using a processing device so that it fits the frame shape of the eyeglass frame. This processing device is a machine that holds the eyeglass lens on a pair of lens chuck shafts, rotates the lens by rotating the lens, and processes the lens into the desired shape by pressing a processing tool such as a grindstone against the lens. At this time, a jig is attached to the eyeglass lens with double-sided tape, and the lens is held by the lens chuck shafts via the jig.

[0003] In recent years, water-repellent lenses, whose lens surface is coated with a water-repellent / oil-repellent material that makes it difficult for dirt such as water and oil to adhere, have been widely used. Since these water-repellent lenses have a slippery surface, when processed in the same way as lenses that have not been treated with water-repellent coating, the adhesive strength of the double-sided tape is insufficient, and the rotation angle of the lens is shifted from the rotation angle of the lens chuck axis, which is a problem of so-called axial misalignment. As a method for preventing this axial misalignment, a method of temporarily providing a protective film on the lens surface is known. In this method, axial misalignment during lens processing can be prevented by forming a protective layer on the lens surface that has good adhesion to the double-sided tape used for fixing the jig and the lens surface. In addition, the protective film can be easily peeled off from the lens after processing.

[0004] The composition for forming the above protective film is required to be able to be uniformly coated on the surface of the water-repellent lens (coatability). In addition, the protective film obtained from this composition is required to have a suitable adhesion (adhesion) that does not peel off from the water-repellent lens during processing and is easily peelable after processing, and is required not to affect the water repellency of the lens after the protective film is peeled off (non-contamination). In addition, since it may take several months from the formation of the protective film on the lens until the peripheral processing is performed, the protective film is also required to have the same adhesion and non-contamination properties even after long-term storage.

[0005] As such a composition, Patent Document 1 describes a composition in which an acrylic resin is dissolved in an organic solvent as a material for forming a temporary protective film on the surface of a plastic eyeglass lens on which an anti-fouling film with water- and oil-repellent properties has been formed.

[0006] Furthermore, Patent Document 2 describes a composition that combines an acrylic oligomer, an acrylic monomer, a thiol compound, and a photoinitiator as a material capable of forming a protective film that has appropriate peel strength when the cured product is peeled off from an adherend. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2009-109611 A [Patent Document 2] International Publication No. 2013 / 073364 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in recent years, there has been an increase in so-called super-water-repellent treatments in which the contact angle of a water droplet on the coating surface is 150° or more. For super-water-repellent lenses that have been treated in this way, the inventions described in Patent Documents 1 and 2 have the problem that they are unable to simultaneously achieve coatability, adhesion, and non-contamination properties.

[0009] The present invention has been made in view of the above-mentioned conventional techniques, and its object is to provide a resin composition capable of forming a protective film which can be uniformly applied even to ultra-water-repellent lenses, particularly those with high antifouling properties, which does not peel off from the water-repellent lens during processing, has appropriate adhesion to enable easy peeling after processing, and has toughness such that the cured film does not break when peeled off, and which does not affect the water repellency of the substrate after peeling, and a method for forming a protective film on a water-repellent lens, which prevents axial misalignment of the lens during processing and enables it to be processed into a desired shape. [Means for solving the problem]

[0010] The present invention is a resin composition for use in a water-repellent lens protective film, which contains (A) a polyfunctional (meth)acrylate having a weight-average molecular weight of 250 to 30,000, (B) a polyfunctional thiol compound, (C) a photopolymerization initiator, and (D) a block copolymer having a weight-average molecular weight of 25,000 to 100,000 and consisting of fluorine-based segments and non-fluorine-based segments, characterized in that the resin composition contains 0.5 to 30 parts by mass of component (B), 0.1 to 25 parts by mass of component (C), and 0.1 to 25 parts by mass of component (D) per 100 parts by mass of component (A).

[0011] The present invention also provides a method for protecting a water-repellent lens by coating the above-mentioned resin composition for a protective film on the water-repellent lens, followed by curing to obtain a cured film as a protective layer. Effect of the Invention

[0012] The resin composition for a water-repellent lens protective film of the present invention has particularly high antifouling properties, and can be uniformly coated even on super-water-repellent lenses, which are difficult to coat on the surface. In addition, the cured film obtained by curing the resin composition for a water-repellent lens protective film of the present invention has an appropriate adhesion to the water-repellent lens, which prevents axial misalignment during processing, and the protective film can be easily peeled off without leaving any residue. [Brief description of the drawings]

[0013] [Figure 1]FIG. 2 is a schematic diagram illustrating a test method for evaluating the retention strength of a protective film in an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram illustrating a method for evaluating the retention strength of a protective film in an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will be described in detail below. In the present invention, "(meth)acrylate" is a generic term including both acrylate and methacrylate. In the present invention, "XX to XX" indicating a numerical range is a concept including the lower limit ("XX") and the upper limit ("XX"), unless otherwise specified. In other words, it means "not less than XX and not more than XX" precisely.

[0015] The resin composition for a water-repellent lens protective film of the present invention is a curable resin composition containing the following components (A), (B), (C) and (D) as essential components. <Component (A): Polyfunctional (meth)acrylate> The (A) polyfunctional (meth)acrylate is not particularly limited as long as it has a weight average molecular weight (Mw) of 250 to 30,000 and has two or more (meth)acryloyl groups in the molecule, and known materials can be used. The (A) component may be used alone or in combination of two or more.

[0016] A preferred example of the (A) polyfunctional (meth)acrylate is a compound represented by the following general formula (Formula 1). [ka]

[0017] In the formula, a is preferably 2-30. R 1R is a hydrocarbon group having 2 to 300 carbon atoms or a hydrocarbon group having 2 to 300 carbon atoms containing at least one selected from the group consisting of an ether oxygen (-O-) and a hydroxyl group (-OH), an isocyanurate ring or a group consisting of an isocyanurate ring and a hydrocarbon group or a hydrocarbon group having 2 to 20 carbon atoms, or a hydrocarbon group having 2 to 250 carbon atoms or a hydrocarbon group having 2 to 250 carbon atoms containing at least one selected from the group consisting of an ether oxygen (-O-) and a hydroxyl group (-OH). 2 is a hydrogen atom or a methyl group.

[0018] Specific examples of the (A) polyfunctional (meth)acrylate include polyfunctional (meth)acrylate monomers such as trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate; polyfunctional (meth)acrylate oligomers such as epoxy-modified (meth)acrylates obtained by reacting a compound having an epoxy group with (meth)acrylic acid; and urethane (meth)acrylates obtained by reacting a diisocyanate compound, a diol compound, and a (meth)acrylate compound having a hydroxyl group.

[0019] Among these, it is preferable to use urethane (meth)acrylate. By using a compound having a flexible urethane bond, the adhesion between the cured film and the water-repellent lens is improved, and the axis deviation during processing can be suppressed. In addition, the toughness of the cured film is improved, and the breakage of the cured film during peeling can be suppressed.

[0020] Specific examples of urethane (meth)acrylates include UN-352 (functional groups: 2, Mw: 3,000), UN-333 (functional groups: 2, Mw: 3,000), UN-353 (functional groups: 2, Mw: 5,000), UN-1255 (functional groups: 2, Mw: 8,000), UN-6200 (functional groups: 2, Mw: 6,500), and UN-6201. (Number of functional groups: 2, Mw: 1,600), UN-9000PEP (Number of functional groups: 2, Mw: 5,000), UN-9200A (Number of functional groups: 2, Mw: 15,000), UN- 3320HA (Number of functional groups: 6, Mw: 1,500), UN-904 (Number of functional groups: 10, Mw: 4,900), UN-953 (Number of functional groups: 20, Mw: 14,000~40 ,000), UN-954 (number of functional groups: 6, Mw: 4,500), UN-6305 (number of functional groups: 2, Mw: 27,000), H-219 (number of functional groups: 9, Mw: 25,000 to 50,000) (all of the above are trade names, manufactured by Negami Chemical Industrial Co., Ltd.), EBECRYL230 (number of functional groups: 2, Mw: 5,000), EBECRYL9260 (number of functional groups: 3, Mw: 1,500), EBECRYL4666 (number of functional groups: 4, Mw: 1,100) (all of the above are trade names, manufactured by Daicel-Allnex Corporation), UX-4101 (number of functional groups: 2, Mw: 6,500), UX-6101 (number of functional groups: 2, Mw: 6,500) (all of the above are trade names, manufactured by Nippon Kayaku Kogyo Co., Ltd.).

[0021] The weight average molecular weight of the (A) polyfunctional (meth)acrylate is preferably 250 to 30,000, and more preferably 500 to 15,000. If the weight average molecular weight is less than 250, the adhesion between the cured film and the water-repellent lens decreases, while if it exceeds 30,000, the toughness of the cured film becomes insufficient and the cured film breaks during peeling, decreasing the workability when peeling the cured film from the water-repellent lens.

[0022] In this specification, the weight average molecular weight was determined in terms of polystyrene by measurement using a gel permeation chromatography apparatus HLC-8220GPC manufactured by Tosoh Corporation, a column TSKgel HZM-M manufactured by Tosoh Corporation, THF as an eluent, and an RI detector.

[0023] The number of (meth)acryloyl groups (number of functional groups) in the molecule of the (A) polyfunctional (meth)acrylate is not particularly limited as long as it is 2 or more, and is, for example, 2 to 30. The upper limit is preferably 20 or less, more preferably 15 or less, further preferably 10 or less, and particularly preferably 8 or less.

[0024] The content of the (A) polyfunctional (meth)acrylate is preferably 70 to 97% by mass, more preferably 75 to 95% by mass, based on the total amount of the (A) to (D) components. When the (A) component content is 70% by mass or more, the toughness of the cured film is improved and breakage of the cured film during peeling is suppressed, improving the workability when peeling the cured film from the water-repellent lens. When the (A) component content is 97% by mass or less, the adhesion between the cured film and the water-repellent lens is appropriately adjusted, making it easy to peel the cured film.

[0025] <Component (B): Multifunctional thiol compound> The polyfunctional thiol compound (B) is not particularly limited as long as it is a compound having two or more thiol groups (-SH groups) in the molecule, and known materials can be used. Note that the (B) component may be used alone or in combination of two or more.

[0026] Specific examples of the (B) polyfunctional thiol compound include trimethylolpropane tris(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptopropionate), tetraethylene glycol bis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), and the like.

[0027] The content of the (B) polyfunctional thiol compound is preferably 0.5 to 30 parts by mass, more preferably 1.0 to 25 parts by mass, per 100 parts by mass of the (A) component. If the content of the (B) component is less than 0.5 parts by mass, per 100 parts by mass of the (A) component, the adhesion between the cured film and the water-repellent lens becomes excessive, making it difficult to peel the cured film, whereas if the content exceeds 30 parts by mass, the toughness of the cured film becomes insufficient, causing the cured film to break during peeling, decreasing the workability when peeling the cured film from the water-repellent lens.

[0028] The ratio of thiol groups derived from component (B) to (meth)acryloxy groups derived from component (A) (hereinafter referred to as (B) / (A) functional group ratio) is preferably 0.05 to 5.0, more preferably 0.10 to 3.0. If the (B) / (A) functional group ratio is less than 0.05, the adhesion between the cured film and the water-repellent lens becomes excessive, making it difficult to peel the cured film, whereas if it exceeds 5.0, the toughness of the cured film becomes insufficient and the cured film breaks during peeling, reducing the workability when peeling the cured film from the water-repellent lens.

[0029] <Component (C): Photopolymerization initiator> The photopolymerization initiator (C) is not particularly limited, and known materials can be used. The photopolymerization initiator (C) may be used alone or in combination of two or more.

[0030] Specific examples of the (C) photopolymerization initiator include acylphosphine oxide-based, oxime ester-based, aromatic ketone-based, quinone-based, alkylphenone-based, imidazole-based, acridine-based, and phenylglycine-based photopolymerization initiators.

[0031] (Acylphosphine oxide photopolymerization initiator) The acylphosphine oxide photopolymerization initiator has an acylphosphine oxide group (>P(=O)-C(=O)- group), and specific examples include (2,6-dimethoxybenzoyl)-2,4,6-pentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide ("IRGACURE-TPO" (BASF)), ethyl-2,4,6-trimethylbenzoylphenylphosphinate, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide ("IRGACURE-819" (BASF)), (2,5-dihydroxyphenyl)diphenylphosphine oxide, (p-hydroxyphenyl)diphenylphosphine oxide, bis(p-hydroxyphenyl)phenylphosphine oxide, tris(p-hydroxyphenyl)phosphine oxide, and the like.

[0032] (Oxime ester photoinitiator) The oxime ester photopolymerization initiator is a photopolymerization initiator having an oxime ester bond, and specific examples include 1,2-octanedione-1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime) (trade name: OXE-01, manufactured by BASF), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone-1-(O-acetyloxime) (trade name: OXE-02, manufactured by BASF), and 1-phenyl-1,2-propanedione-2-[O-(ethoxycarbonyl)oxime] (trade name: Quantacure-PDO, manufactured by Nippon Kayaku Co., Ltd.).

[0033] (Aromatic ketone photopolymerization initiator) Specific examples of aromatic ketone-based photopolymerization initiators include benzophenone, N,N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), N,N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one ("IRGACURE-651" (BASF)), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one ("IRGACURE-369" (BASF)), 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one ("IRGACURE-907" (BASF)), and the like.

[0034] (Quinone-based photopolymerization initiator) Specific examples of quinone-based photopolymerization initiators include 2-ethylanthraquinone, phenanthrenequinone, 2-t-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, and 2,3-dimethylanthraquinone.

[0035] (Alkylphenone photopolymerization initiator) Specific examples of alkylphenone-based photopolymerization initiators include benzoin-based compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin phenyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one ("IRGACURE-651" (BASF)), 1-hydroxy-cyclohexyl-phenyl-ketone ("IRGACURE-184" (BASF)), 2-hydroxy-2-methyl-1 -phenyl-propan-1-one ("IRGACURE-1173" (BASF)), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one ("IRGACURE-2959" (BASF)), 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one ("IRGACURE-127" (BASF)), and the like.

[0036] (Imidazole-based photopolymerization initiator) Specific examples of imidazole-based photopolymerization initiators include 2,4,5-triarylimidazole dimers, and more specifically, 2-(o-chlorophenyl)-4,5-diphenylimidazole dimers such as 2-(2-chlorophenyl)-1-[2-(2-chlorophenyl)-4,5-diphenyl-1,3-diazol-2-yl]-4,5-diphenylimidazole, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazole dimers, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimers, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimers, and 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimers.

[0037] Among these, it is preferable to use an aromatic ketone-based photopolymerization initiator from the viewpoint of curability when using various light sources.

[0038] The content of the (C) photopolymerization initiator is preferably 0.1 to 25 parts by mass, more preferably 0.5 to 20 parts by mass, relative to 100 parts by mass of the (A) component. If the content of the (C) component is less than 0.1 parts by mass relative to 100 parts by mass of the (A) component, the curing is insufficient, resulting in a decrease in the adhesion between the cured film and the water-repellent lens and a decrease in the toughness of the cured film, and the water repellency of the substrate decreases due to the residue of the uncured components when the protective film is peeled off. If the content of the (C) component is more than 25 parts by mass relative to 100 parts by mass of the (A) component, the photopolymerization initiator becomes excessive, and the water repellency of the substrate decreases due to the residue of the photopolymerization initiator when the protective film is peeled off.

[0039] <Component (D): Block copolymer consisting of fluorine-based segments and non-fluorine-based segments> The block copolymer consisting of a fluorine-based segment and a non-fluorine-based segment, which is the component (D), can be made of a known material. The component (D) may be used alone or in combination of two or more kinds.

[0040] A specific example of the block copolymer consisting of (D) fluorine-based segments and non-fluorine-based segments is a block copolymer of an ethylenically unsaturated compound. By using a block copolymer consisting of fluorine-based segments and non-fluorine-based segments, the (D) component is more likely to segregate on the surface when the resin composition for forming a protective film is applied to a water-repellent lens, and the coatability to the water-repellent lens can be improved. In addition, the increased surface segregation makes it difficult for the (D) component to inhibit the curing reaction between the (A) polyfunctional (meth)acrylate and the (B) polyfunctional thiol compound inside the coating film, and therefore a cured film with greater toughness can be obtained.

[0041] (D) Commercially available block copolymers consisting of fluorine-based segments and non-fluorine-based segments include Modiper F206, Modiper F246, and Modiper F3636 (all trade names, manufactured by NOF Corporation).

[0042] The weight average molecular weight of the block copolymer (D) consisting of a fluorine-based segment and a non-fluorine-based segment is preferably 25,000 to 100,000, more preferably 30,000 to 80,000. If the weight average molecular weight is less than 25,000, the water repellency of the substrate decreases due to the surfactant residue when the protective film is peeled off, and if it exceeds 100,000, the coatability to a water-repellent lens decreases. The method for measuring the weight average molecular weight is the same as the method for measuring the weight average molecular weight of the polyfunctional (meth)acrylate (A).

[0043] The content of the (D) block copolymer consisting of a fluorine-based segment and a non-fluorine-based segment is preferably 0.1 to 25 parts by mass, more preferably 0.5 to 20 parts by mass, and particularly preferably 1.0 to 15 parts by mass, per 100 parts by mass of the (A) component. If the content of the (D) component is less than 0.1 part by mass per 100 parts by mass of the (A) component, the coatability onto a water-repellent lens will be insufficient, whereas if it exceeds 25 parts by mass, the water repellency of the substrate will decrease due to surfactant residues when the protective film is peeled off.

[0044] <Diluent> The resin composition for water-repellent lens protective film of the present invention may be diluted with an organic solvent or a reactive diluent to homogenize the reaction system and facilitate coating. Examples of such organic solvents include alcohol-based solvents, aromatic hydrocarbon-based solvents, ether-based solvents, ester-based solvents, ether ester-based solvents, and ketone-based solvents. As the reactive diluent, a monofunctional photopolymerizable monomer having a vinyl group, an acryloyl group, a methacryloyl group, or the like can be used. Among these, a (meth)acrylate compound having an acryloyl group or a methacryloyl group is preferred, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, n-hexyl (meth)acrylate, and stearyl (meth)acrylate. The amount of the diluent to be added may be adjusted as desired within a range that does not impair the characteristics of the present invention.

[0045] The resin composition for water-repellent lens protective film of the present invention may contain additives in appropriate amounts, such as colorants such as pigments and dyes, stabilizers, flame retardants, organic fillers, plasticizers, antioxidants, defoamers, coupling agents, and rheology control agents, within the scope of not impairing the characteristics of the present invention.

[0046] <Formation of protective film> The method for forming a protective film using the resin composition for water-repellent lens protective film of the present invention is not particularly limited, but examples thereof include methods such as dip coating, spray coating, and spin coating. The thickness of the protective film formed using the resin composition for water-repellent lens protective film of the present invention is not particularly limited, but from the viewpoint of preventing axial deviation during peripheral processing of the lens and preventing scratches during processing and storage, it is preferably 10 μm or more. On the other hand, the thickness of the coating film is preferably 100 μm or less so that position deviation does not occur when identifying the center of the lens.

[0047] After coating the resin composition for water-repellent lens protective film of the present invention, the composition coated on the substrate can be irradiated with active energy rays such as ultraviolet rays to obtain a protective film. Examples of light sources used in the active energy ray irradiation step include UV-LED (ultraviolet LED), low pressure mercury lamp, high pressure mercury lamp, ultra-high pressure mercury lamp, metal halide lamp, carbon arc, xenon arc, gas laser, solid laser, and electron beam irradiation device. Among these, UV-LEDs are preferred as they consume significantly less power than conventional UV lamps and generate less heat from their light source than UV lamps. Furthermore, by using UV-LEDs with peak irradiance of 395 nm or more, which is close to visible light, the impact of ultraviolet light exposure on the water-repellent lens can be suppressed and the occurrence of cracks in the water-repellent layer can be suppressed. EXAMPLES

[0048] <Component (A): Polyfunctional (meth)acrylate> A-1: Ethylene oxide modified bisphenol A dimethacrylate (Blenmer PDBE-200A, NOF Corporation: bifunctional, weight average molecular weight 541) A-2: Urethane acrylate (Art Resin UN-333, manufactured by Negami Chemical Industries, Ltd.: bifunctional, weight average molecular weight 3,000) A-3: Polyether-based urethane acrylate (Art Resin UN-1255, manufactured by Negami Chemical Industries, Ltd.: bifunctional, weight average molecular weight 8,000) A-4: Polycarbonate-based urethane acrylate (Art Resin UN-9200A, manufactured by Negami Chemical Industries, Ltd.: bifunctional, weight average molecular weight 15,000) A-5: Aliphatic urethane acrylate (EBECRYL4666, Daicel-Allnex: 4 functional groups, weight average molecular weight 1,100) A'-1: Ethylene glycol dimethacrylate (Light Ester EG, Kyoeisha Chemical Co., Ltd.: bifunctional, weight average molecular weight 198) A'-2: Urethane acrylate (Shiko UV-3700B manufactured by Mitsubishi Chemical Corporation: bifunctional, weight average molecular weight 38,000)

[0049] <Component (B): Multifunctional thiol compound> B-1: Dipentaerythritol hexakis(3-mercaptopropionate) (DPMP manufactured by SC Organic Chemicals Co., Ltd.: 6 functional groups, weight average molecular weight 783) B-2: Trimethylolpropane tris(3-mercaptopropionate) (TMMP manufactured by SC Organic Chemicals Co., Ltd.: trifunctional, weight average molecular weight 399)

[0050] <Component (C): Photopolymerization initiator> C-1: 2,2-dimethoxy-2-phenylacetophenone (OMNIRAD651, manufactured by IGM)

[0051] <Component (D): Block copolymer consisting of fluorine-based segments and non-fluorine-based segments> D-1: Fluorine-based block copolymer (Modiper F206, NOF Corporation, weight average molecular weight 38,000) D-2: Fluorine-based block copolymer (Modiper F246, NOF Corporation, weight average molecular weight 25,000) D-3: Fluorine-based block copolymer (Modiper F3636, NOF Corporation, weight average molecular weight 77,000) D'-1: Polyether modified silicone oil (DOWSIL L-7001 Dow Toray Co., Ltd.)

[0052] <Diluent> MEK: Methyl ethyl ketone IPAC: Isopropyl acetate BA: Butyl acrylate

[0053] Components (A) to (D) and a diluent were added to a mixing vessel in the proportions shown in Tables 1 to 3, and stirred at room temperature (23°C) with a three-one motor under UV protection until homogenous, to obtain a sample of a resin composition for water-repellent lens protective film. The obtained resin compositions for water-repellent lens protective film of each of the Examples and Comparative Examples were evaluated for coatability, adhesion (retention, peelability, toughness), and non-staining properties as described below. The results are shown in Tables 1 to 3.

[0054] [Protective film formation on super water-repellent lenses] For the evaluation, a plastic lens (diameter 75 mm) with an ultra-water-repellent layer with a pure water contact angle of 150° or more was used. The resin compositions for water-repellent lens protective films of the Examples and Comparative Examples were coated onto this ultra-water-repellent lens by dip coating so that the film thickness after curing was 20 μm. After coating, the lens was left to stand for 10 minutes at room temperature (23°C) in a space that was protected from ultraviolet rays and dried, and then the lens was exposed to an ultraviolet ray irradiation device (Unijet E110IIHD-395 manufactured by Ushio Inc.) with an illumination intensity of 500 mW / cm. 2 The contact angle of the superhydrophobic lens was calculated by placing a 1 μL droplet of pure water on the lens surface and measuring the angle between the lens and the droplet.

[0055] [Coatability evaluation] The resin composition for water-repellent lens protection film was coated on a super water-repellent lens by the dip coating method described above, and cured. If repelling was observed, the maximum width of the uncoated part from the edge of the lens was measured as the repelling size, and it was evaluated as follows. The coatability was considered to be acceptable if the repelling size was 10 mm or less. ◎: No repelling. ◯: The uncoated portion from the edge is 5 mm or less. △: The uncoated portion from the edge was more than 5 mm and not more than 10 mm. ×: The portion that is not coated from the edge is greater than 10 mm.

[0056] [Retention strength evaluation] The retention of the protective film formed on the super water-repellent lens was evaluated as an evaluation of the axial misalignment during the processing of the lens periphery. The retention evaluation was performed in accordance with JIS-Z0237, with different loads. A 24 mm wide, 130 mm long adhesive tape (CT405AP-24 manufactured by Nichiban Co., Ltd.) was attached to the center of the super water-repellent lens with the protective film formed, which had been stored for three months in an environment of temperature: 23°C and relative humidity: 50% (see Figure 1). At this time, a mark was made with an oil-based pen so that it overlaps with the center of the concave part of the lens. A load of 14.7 N was applied to the end of the adhesive tape opposite to the end attached to the lens, and the distance at which the mark on the convex surface and the mark on the concave surface were misaligned after 10 minutes was measured (see Figure 2). The obtained measurement results were evaluated as follows. A retention measurement result of 2.0 mm or less was considered to be acceptable. ◎: The holding force measurement result is 0.0 mm. ◯: The retention force measurement result is greater than 0.0 mm and equal to or less than 0.5 mm. △: The retention force measurement result is greater than 0.5 mm and less than 2.0 mm. ×: The holding force measurement result is greater than 2.0 mm.

[0057] [Peelability] Adhesive tape (CT405AP-24, manufactured by Nichiban) was applied to the edge of a super water-repellent lens with a protective film formed thereon that had been stored for three months in an environment of temperature: 23°C and relative humidity: 50%, and then the tape was peeled off by hand. The adhesive tape was repeatedly applied and peeled off in the same position, and the number of times the tape had to be peeled off before the protective film peeled off was counted and evaluated as follows. The releasability was evaluated as passing, with a rating of ◯ or △. ◯: The protective film can be peeled off with one tape peel. △: The protective film can be peeled off by peeling the tape 2 to 5 times. ×: The protective film could not be peeled off even after five or more tape peeling attempts.

[0058] [Toughness] After applying adhesive tape (CT405AP-24 manufactured by Nichiban Co., Ltd.) to the edge of the super water-repellent lens with the protective film formed thereon, which had been stored for three months in an environment of temperature: 23°C and relative humidity: 50%, the tape was peeled off by hand. The shape of the peeled protective film was confirmed and evaluated as follows. The toughness was evaluated as ◯ or △. A: No cracks in the protective film. △: The protective film has a crack of less than 30 mm. ×: The protective film was broken and could not be peeled off by peeling the tape once.

[0059] [Non-polluting] After the protective film was peeled off from a super water-repellent lens with a protective film formed, which had been stored for three months in an environment of temperature: 23°C and relative humidity: 50%, a line was drawn on the lens with an oil-based marker (black marker ink made by Teranishi Chemical Industry Co., Ltd.), and the ink repelling was observed and rated as follows. Note that the lens surface before the protective film is formed repels oil-based marker ink, but if contaminants remain on the lens surface, the water repellency decreases. Note that non-contamination was rated as passing with a rating of ◯ or △. ○: Ink drawn in a straight line turns into dots. △: Straight lines drawn with ink become thin lines. ×: No ink repellency is observed in the straight line drawn.

[0060] From the results of Tables 1 and 2, the resin compositions of Examples 1 to 19 all had good coatability on super water repellent lenses. Furthermore, the protective films obtained by curing the resin compositions of Examples 1 to 19 had adequate adhesion to super water repellent lenses even after three months of storage in an environment of temperature: 23°C and relative humidity: 50%, and retaining power, peelability, and toughness were all at high levels. Furthermore, the decrease in water repellency of the super water repellent lens after peeling off the protective film was suppressed, and the non-contamination properties were also excellent.

[0061] On the other hand, from the results of Table 3, in Comparative Examples 1 and 2, the weight average molecular weight of the (A) component was too small or too large, so that the retention or toughness of the obtained protective film on the super water repellent lens was insufficient. In Comparative Examples 3 and 4, the content of the (B) component was too small or too large, so that the peelability or toughness of the obtained protective film from the super water repellent lens was insufficient. In Comparative Example 5, the content of the (C) component was too small, so that the retention, toughness, and non-contamination of the obtained protective film on the super water repellent lens were insufficient. In Comparative Example 6, the content of the (C) component was too large, so that the non-contamination of the obtained protective film was insufficient. In Comparative Examples 7, 9, and 10, the content of the (D) component was too small, a silicon-based surfactant was used as the (D) component, or no (D) component was included, so that the coatability on the super water repellent lens was insufficient. In Comparative Example 8, the content of the (D) component was too large, so that the non-contamination of the obtained protective film was insufficient.

[0062] [Table 1]

[0063] [Table 2]

[0064] [Table 3]

Claims

1. A resin composition comprising the following components (A) to (D): A resin composition for a water-repellent lens protective film, comprising, relative to 100 parts by mass of the component (A), 0.5 to 30 parts by mass of the component (B), 0.1 to 25 parts by mass of the component (C), and 0.1 to 25 parts by mass of the component (D). Component (A): A polyfunctional (meth)acrylate having a weight average molecular weight of 250 to 30,000. Component (B): polyfunctional thiol compound Component (C): Photopolymerization initiator Component (D): A block copolymer having a weight average molecular weight of 25,000 to 100,000 and consisting of a fluorine-based segment and a non-fluorine-based segment.

2. 13. A method for protecting a water-repellent lens by applying the resin composition for a water-repellent lens protective film according to claim 1 to a water-repellent lens and curing the composition to provide a protective film thereon.

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