Evaluating method of fingerprint resistance, method of producing optical member, and optical member

Abstract

To provide an evaluation method of fingerprint resistance capable of evaluating fingerprint resistance quantitatively and with high reproducibility, a method for producing an optical member using the evaluation method, and an optical members with excellent fingerprint resistance.SOLUTION: The evaluation method of fingerprint resistance for evaluating the fingerprint resistance of the surface of an evaluation object using the lightness L* before and after application of the oleic acid diluent as an index, includes the steps of: measuring the lightness L* defined by CIE1976 L*a*b* color system on the surface of the evaluation object; applying oleic acid diluent over the surface of the evaluation object; and after drying the oleic acid diluent, measuring the lightness L* defined by CIE1976 L*a*b* color system; and evaluating lightness L* before and after applying oleic acid diluent as the index.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for evaluating fingerprint resistance, a method for producing an optical member utilizing said evaluation method, and an optical member, in particular an optical member having excellent fingerprint resistance. [Background technology]

[0002] In recent years, touch panels that serve as both a display device and an input means have come into widespread use in various electronic devices. A hard coat film having a hard coat layer is usually provided on the surface of the touch panel to prevent scratches.

[0003] Since such touch panels are often operated with fingers, fingerprints caused by finger oils are usually left on the surface of the touch panel. When fingerprints are left on the surface of the touch panel, the appearance is deteriorated and the displayed image becomes difficult to see. Therefore, the above-mentioned hard coat film is required to have fingerprint resistance, which is a performance that makes it difficult to see fingerprints.

[0004] Conventionally, there has been no clear index for evaluating fingerprint resistance, and only the contact angle of water or oleic acid has been measured as a reference, or the appearance of a fingerprint when it is actually attached has been evaluated as a sensory evaluation. However, there is a problem that the correlation between the measured contact angle and the sensory evaluation is low, and the reproducibility is low when the sensory evaluation is performed only by visual observation.

[0005] Therefore, Patent Document 1 proposes a contamination evaluation method in which a test specimen is irradiated with light, and scattered light reflected or transmitted by the test specimen is detected to evaluate the contamination level of the test specimen's surface. Specifically, the method utilizes ΔE*ab in the L*a*b* color model defined by the International Commission on Illumination (CIE), and evaluates the contamination level based on the difference between ΔE*ab after the surface is artificially contaminated and ΔE*ab after the surface is subsequently cleaned. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2008 / 029946 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when ΔE*ab is used as in Patent Document 1, the difference between ΔE*ab after the surface is artificially contaminated and ΔE*ab after the subsequent cleaning process is absolutely small, making it difficult to determine the degree of fingerprint adhesion. Therefore, it is not a sufficient index for evaluating fingerprint resistance.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a method for evaluating fingerprint resistance that can quantitatively and highly reproducibly evaluate fingerprint resistance, a method for producing optical components using the evaluation method, and an optical component having excellent fingerprint resistance. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, firstly, the present invention provides a method for evaluating fingerprint resistance, characterized in that the lightness L* of the surface of an object to be evaluated as defined by the CIE1976 L*a*b* color system is measured, then a diluted oleic acid solution is applied to the surface of the object to be evaluated, the surface is dried, and the lightness L* as defined by the CIE1976 L*a*b* color system is measured, and the fingerprint resistance of the surface of the object to be evaluated is evaluated using the lightness L* before and after application of the diluted oleic acid solution as an index (Invention 1).

[0010] In the present invention, the term "fingerprint resistance" refers to the performance of making fingerprints difficult to see with the naked eye.

[0011] According to the above invention (Invention 1), fingerprint resistance can be quantitatively evaluated with high reproducibility. Also, there is a high correlation with visual evaluation.

[0012] In the above invention (Invention 1), the oleic acid dilution is preferably a liquid obtained by diluting oleic acid with a volatile solvent. The volatile solvent is preferably an alcohol-based solvent, and the alcohol-based solvent is preferably ethanol. The concentration of oleic acid in the oleic acid dilution is preferably 0.12% by mass or more and 12% by mass or less. The oleic acid dilution is preferably applied to the surface of the evaluation object by a bar coater.

[0013] In the above invention (Invention 1), the lightness L* before application of the diluted oleic acid solution is defined as pre-application lightness L*, the lightness L* after application of the diluted oleic acid solution is defined as post-application lightness L*, and the fingerprint resistance of the surface of the evaluation object is evaluated by the change amount ΔL* obtained by subtracting the pre-application lightness L* from the post-application lightness L*, or the lightness L* before application of the diluted oleic acid solution is defined as pre-application lightness L*, and the lightness L* after application of the diluted oleic acid solution is defined as post-application lightness L*, and the fingerprint resistance of the surface of the evaluation object is evaluated by the change rate (%) calculated by the following formula (Inventions 2 and 3). It is also possible to evaluate by both. Rate of change = {(L* after application - L* before application) / L* before application} x 100

[0014] In the above inventions (Inventions 1 to 3), it is preferable that a hard coat layer is present on the surface of the evaluation object to which the diluted oleic acid solution is applied (Invention 4).

[0015] In the above inventions (Inventions 1 to 4), the object to be evaluated is preferably an optical member (Invention 5).

[0016] Secondly, the present invention provides a method for producing an optical member, characterized by comprising: a step of obtaining an optical member; and an evaluation step of evaluating the fingerprint resistance of the optical member as an object to be evaluated by the fingerprint resistance evaluation method (Inventions 1 to 5) (Invention 6).

[0017] Thirdly, the present invention provides an optical element characterized in that, when the lightness L* defined by the CIE1976 L*a*b* color system before coating of the diluted oleic acid solution is defined as pre-coating lightness L*, and the lightness L* defined by the CIE1976 L*a*b* color system after coating of the diluted oleic acid solution is defined as post-coating lightness L*, the change ΔL* obtained by subtracting the pre-coating lightness L* from the post-coating lightness L* is less than 0.3 (Invention 7).

[0018] Fourthly, the present invention provides an optical element characterized in that, when the lightness L* defined by the CIE1976 L*a*b* color system before application of the diluted oleic acid solution is defined as pre-application lightness L*, and the lightness L* defined by the CIE1976 L*a*b* color system after application of the diluted oleic acid solution is defined as post-application lightness L*, the rate of change calculated by the following formula is 6% or less (Invention 8). Rate of change = {(L* after application - L* before application) / L* before application} x 100

[0019] In the above inventions (Inventions 7 and 8), it is preferable that a hard coat layer is present on the surface of the optical member to which the diluted oleic acid solution is applied (Invention 9). Effect of the Invention

[0020] According to the method for evaluating fingerprint resistance of the present invention, the fingerprint resistance can be evaluated quantitatively and with high reproducibility. Also, according to the method for producing an optical member of the present invention, the fingerprint resistance can be evaluated quantitatively and with high reproducibility, and then the optical member can be produced. Furthermore, the optical member of the present invention has excellent fingerprint resistance. [Brief description of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view of an optical member according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described. [Method for evaluating fingerprint resistance] A method for evaluating fingerprint resistance according to one embodiment of the present invention involves measuring the lightness L* of the surface of an object to be evaluated as defined by the CIE 1976 L*a*b* color system, applying a diluted oleic acid solution to the surface of the object to be evaluated, drying the surface, and then measuring the lightness L* as defined by the CIE 1976 L*a*b* color system. The lightness L* before and after application of the diluted oleic acid solution are used as indicators to evaluate the fingerprint resistance of the surface of the object to be evaluated.

[0023] According to the above evaluation method, the fingerprint resistance can be evaluated quantitatively and with high reproducibility. In addition, there is a high correlation between the evaluation and visual evaluation.

[0024] The type of the object to be evaluated is not particularly limited, and the fingerprint resistance can be evaluated for various objects to be evaluated according to the above-mentioned fingerprint resistance evaluation method. Such objects to be evaluated are preferably objects on which fingerprints are easily attached or on which fingerprints are easily noticeable, and particularly preferably objects having a smooth surface. The object to be evaluated may be transparent, opaque, colorless, or colored, and is preferably transparent, and particularly preferably colorless and transparent. Specific objects to be evaluated include, for example, optical members, optical disks, housings, and the like. Examples of optical members include, for example, plastic films, plastic plates, glass plates, those provided with various functional layers (transparent conductive films, metal layers, silica layers, hard coat layers, anti-glare layers, etc.) on one or both sides thereof, displays, touch panels, or parts thereof that include them. Among the above, plastic films, plastic plates, glass plates, displays, touch panels, etc. that have a hard coat layer on the outermost surface (the surface that the finger touches) are particularly preferred.

[0025] The method for measuring the lightness L* will be described in detail later, but when the object to be evaluated is a transparent member (particularly a transparent film), it is preferable to measure the object after attaching it to a black board. This allows the fingerprints attached to the object to be evaluated to be measured as lightness L* more accurately.

[0026] The color of the black plate used in this case is preferably defined by the CIE1976 L*a*b* color system as follows: lightness L* is 0.1 to 60, chromaticity a* is -40 to 40, and chromaticity b* is -40 to 40, and more preferably lightness L* is 1 to 30, chromaticity a* is -20 to 20, and chromaticity b* is -20 to 20, and even more preferably lightness L* is 2 to 15, chromaticity a* is -10 to 10, and chromaticity b* is -10 to 10.

[0027] The material of the black plate is not particularly limited, and may be, for example, a plastic plate, a metal plate, a ceramic plate, etc., among which, a plastic plate that is easy to produce the above-mentioned black color tone is preferable. Examples of the plastic plate include an acrylic plate, a polycarbonate plate, a polyethylene terephthalate plate, a polyvinyl chloride resin plate, etc., among which, an acrylic plate that is easy to produce the above-mentioned black color tone is preferable.

[0028] The method for attaching the object to be evaluated to the black plate is not particularly limited, but it is preferable to use an adhesive sheet having a highly transparent adhesive layer with a refractive index close to 1. The haze value of the adhesive layer (measured in accordance with JIS K7136:2000) is preferably 10% or less, more preferably 5% or less, and even more preferably 1% or less. The refractive index of the adhesive layer (method B according to JIS K7142) is preferably 1.2 to 1.8, more preferably 1.3 to 1.6, and even more preferably 1.4 to 1.55.

[0029] The diluted oleic acid solution to be applied to the surface of the evaluation object is preferably a solution obtained by diluting oleic acid with a volatile solvent. The volatile solvent preferably has a boiling point of 35 to 110° C. Examples of such volatile solvents include alcohols such as methanol, ethanol, butanol, and isopropyl alcohol; ethers such as diethyl ether and tetrahydrofuran; ketones such as acetone; esters such as ethyl acetate; aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene and toluene; and halogenated hydrocarbons such as methylene chloride and trichloroethane. These can be used alone or in combination of two or more.

[0030] Among the above, from the viewpoint of increasing the lightness L* after application of the diluted oleic acid solution and facilitating evaluation of fingerprint resistance, alcohol-based solvents are preferred, and ethanol is particularly preferred.

[0031] The concentration of oleic acid in the diluted oleic acid solution is preferably 0.12% by mass or more as a lower limit, more preferably 0.15% by mass or more, and even more preferably 0.18% by mass or more. This makes it closer to how easily actual fingerprints are attached. The concentration of oleic acid in the diluted oleic acid solution is preferably 12% by mass or less as an upper limit, more preferably 6% by mass or less, more preferably 2% by mass or less, and even more preferably 0.5% by mass or less. This makes it closer to how easily actual fingerprints are wiped off.

[0032] As a method for applying the diluted oleic acid solution to the surface of the evaluation object, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, etc. can be used. Among the above, the bar coating method, i.e., application by a bar coater, is preferable. By using a bar coater, the diluted oleic acid solution can be uniformly applied to the flat surface of the evaluation object, and an oleic acid layer can be uniformly formed on the surface of the evaluation object, making it possible to accurately measure the lightness L* after application of the diluted oleic acid solution. As the bar coater, a wire bar is particularly preferable.

[0033] After the diluted oleic acid solution is applied to the surface of the evaluation object, the diluted oleic acid solution is dried to form an oleic acid layer on the surface of the evaluation object. The drying conditions may be appropriately determined depending on the dilution solvent used, but from the viewpoint of uniformly forming an oleic acid layer on the surface of the evaluation object, it is preferable to dry at 5°C to 80°C, particularly 20°C to 40°C. In particular, when ethanol is used as the dilution solvent, it is preferable to dry naturally at room temperature and normal pressure (mainly 23°C, 50% RH).

[0034] After the diluted oleic acid solution has been dried as described above, the lightness L* of the surface of the evaluation object (the surface on which the oleic acid layer is formed) is measured again by the same method as described above.

[0035] Here, the lightness L* measured before application of the diluted oleic acid solution is referred to as the “lightness L* before application,” and the lightness L* measured after application of the diluted oleic acid solution is referred to as the “lightness L* after application.” In this embodiment, the lightness L* before application and the lightness L* after application are used as indicators to evaluate the fingerprint resistance of the surface of the evaluation object.

[0036] Specifically, first, the fingerprint resistance of the surface of the evaluation object can be evaluated by the change amount ΔL* obtained by subtracting the brightness L* before application from the brightness L* after application. In this case, it can be said that the smaller the change amount ΔL*, the better the fingerprint resistance. In order to have excellent fingerprint resistance, the change amount ΔL* is preferably less than 0.3, more preferably 0.2 or less, particularly preferably 0.12 or less, and further preferably 0.04 or less. It is most preferable that the lower limit of the change amount ΔL* is 0, but usually, it is preferably 0.01 or more, and particularly preferably 0.02 or more.

[0037] Secondly, the fingerprint resistance of the surface of the evaluation object can be evaluated based on the rate of change (%) of lightness L* calculated by the following formula. Rate of change = {(L* after application - L* before application) / L* before application} x 100 In this case, it can be said that the smaller the rate of change, the better the fingerprint resistance. In order to have excellent fingerprint resistance, the rate of change in lightness L* is preferably 6% or less, more preferably 4% or less, particularly preferably 2% or less, further preferably 1.0% or less, and most preferably 0.9% or less. It is most preferable that the lower limit of the rate of change is 0%, but usually it is preferably 0.01% or more, particularly preferably 0.1% or more.

[0038] In the present invention, the method for evaluating fingerprint resistance using the pre-coating lightness L* and the post-coating lightness L* as indicators is not limited to the above. For example, (post-coating lightness L*) 2 -(Lightness before application L*) 2 Alternatively, the value of the square root of the value can be used as the index.

[0039] [Method of producing optical members] A method for producing an optical member according to an embodiment of the present invention includes a step of obtaining an optical member, and an evaluation step of evaluating the fingerprint resistance of the optical member as an evaluation target by the above-mentioned fingerprint resistance evaluation method. According to this method for producing an optical member, the fingerprint resistance can be quantitatively evaluated with high reproducibility in the evaluation step, and then the optical member can be produced. Therefore, optical members with excellent fingerprint resistance can be produced with a high yield.

[0040] More specifically, it is preferable to manufacture an optical component as a sample (a process for obtaining an optical component), evaluate the fingerprint resistance of the optical component as the evaluation subject using the fingerprint resistance evaluation method described above (evaluation process), and manufacture the optical component using the same manufacturing method as the manufacturing method for the sample that is determined to have excellent fingerprint resistance (a process for obtaining an optical component).

[0041] The types of optical members include those mentioned above. Among them, plastic films, plastic plates, glass plates, displays, touch panels, and the like, each having a hard coat layer on the outermost surface (the surface that comes into contact with a finger), are particularly preferred.

[0042] The optical member itself can be manufactured by a conventionally known method, however, an optical member having excellent fingerprint resistance is preferably manufactured by the method described below.

[0043] [Optical Members] The optical member according to the first embodiment of the present invention is an optical member in which the change ΔL* obtained by subtracting the pre-coating lightness L* from the post-coating lightness L* is less than 0.3. The optical member according to the second embodiment of the present invention is an optical member in which the change rate calculated by the following formula based on the post-coating lightness L* and the pre-coating lightness L* is 6% or less. Rate of change = {(L* after application - L* before application) / L* before application} x 100

[0044] The optical member according to the first embodiment and the optical member according to the second embodiment are excellent in fingerprint resistance, that is, excellent in performance in which fingerprints attached thereto are difficult to see. This excellent fingerprint resistance has been evaluated quantitatively and with high reproducibility.

[0045] From the viewpoint of fingerprint resistance, the change amount ΔL* in the optical member according to the first embodiment is preferably 0.2 or less, more preferably 0.12 or less, and even more preferably 0.04 or less. From the viewpoint of fingerprint resistance, the change rate in the optical member according to the second embodiment is preferably 4% or less, more preferably 2% or less, more preferably 1.0% or less, and most preferably 0.9% or less. The lower limit of the change amount ΔL* is most preferably 0, but is usually preferably 0.01 or more, and especially preferably 0.02 or more. The lower limit of the change rate is most preferably 0, but is usually preferably 0.01% or more, and especially preferably 0.1% or more.

[0046] The types of optical members according to the present embodiment include those mentioned above. Among them, plastic films, plastic plates, glass plates, displays, touch panels, and the like having a hard coat layer on the outermost surface (the surface that comes into contact with a finger) are particularly preferred.

[0047] The optical member according to this embodiment will be described with reference to FIG. As shown in FIG. 1, the optical member 1 according to this embodiment comprises a substrate 11 and a hard coat layer 12 formed on one surface of the substrate 11.

[0048] 1. Each component 1-1. Base material The substrate 11 of the optical member 1 according to this embodiment is not particularly limited, but preferred examples include a plastic film, a plastic plate, and a glass plate. On the surface of the substrate 11 opposite to the hard coat layer 12, various functional layers, such as a transparent conductive film, a metal layer, a silica layer, a hard coat layer, an anti-glare layer, etc., may be provided. In addition, various functional layers, such as a transparent conductive film, a metal layer, a silica layer, an anti-glare layer, etc., may be provided between the substrate 11 and the hard coat layer 12.

[0049] Examples of plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyolefin films such as polyethylene and polypropylene films, cellophane, diacetyl cellulose films, triacetyl cellulose films, acetyl cellulose butyrate films, polyvinyl chloride films, polyvinylidene chloride films, polyvinyl alcohol films, ethylene-vinyl acetate copolymer films, polystyrene films, polycarbonate films, polymethylpentene films, polysulfone films, polyether ether ketone films, polyether sulfone films, polyether imide films, fluororesin films, polyamide films, acrylic resin films, polyurethane resin films, norbornene-based polymer films, cyclic olefin-based polymer films, cyclic conjugated diene-based polymer films, and vinyl alicyclic hydrocarbon polymer films, or laminated films thereof. Among these, polyethylene terephthalate films, polycarbonate films, and norbornene-based polymer films are preferred from the standpoint of mechanical strength, etc.

[0050] Furthermore, in the above-mentioned plastic film, for the purpose of improving the adhesion to a layer (such as the hard coat layer 12 or an adhesive layer) provided on the surface, one or both sides may be subjected to a surface treatment such as a primer treatment, an oxidation method, or a roughening method, as desired. Examples of the oxidation method include corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet light treatment, etc., and examples of the roughening method include sandblasting and solvent treatment, etc. These surface treatment methods are appropriately selected depending on the type of plastic film, but generally, the corona discharge treatment method is preferably used in terms of effectiveness and operability.

[0051] The thickness of the plastic film is usually about 15 to 300 μm, and preferably about 30 to 200 μm.

[0052] The plastic plate is not particularly limited, and examples thereof include an acrylic plate, a polycarbonate plate, etc. The thickness of the plastic plate is not particularly limited, but is usually 0.3 to 5 mm, and preferably 0.5 to 3 mm.

[0053] The glass plate is not particularly limited, and examples thereof include chemically strengthened glass, alkali-free glass, quartz glass, soda-lime glass, barium-strontium-containing glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate glass, etc. The thickness of the glass plate is not particularly limited, but is usually 0.1 to 5 mm, and preferably 0.2 to 3 mm.

[0054] 1-2.Hard coat layer The hard coat layer 12 of the optical member 1 in this embodiment may be formed from any material as long as the amount of change ΔL* or the rate of change, using the post-coating lightness L* and the pre-coating lightness L* as indicators, satisfies the above-mentioned values, but is preferably formed by curing the coating composition C described below. The coating composition C makes it easy to form the hard coat layer 12 that satisfies the above-mentioned values.

[0055] The coating composition C in this embodiment contains an active energy ray-curable component, fine particles, and a predetermined surface conditioner.

[0056] (1) Each component (1-1) Active energy ray-curable component By including an active energy ray-curable component in the coating composition C, the hard coat layer 12 obtained by curing the coating composition C with active energy rays has the desired hardness and scratch resistance.

[0057] Examples of the active energy ray curable component include a multifunctional (meth)acrylate monomer, a (meth)acrylate prepolymer, and an active energy ray curable polymer. As the active energy ray curable component, it is preferable to use at least a multifunctional (meth)acrylate monomer, and it is particularly preferable to use a multifunctional (meth)acrylate monomer and a (meth)acrylate prepolymer in combination. In this specification, (meth)acrylate means both acrylate and methacrylate. The same applies to other similar terms.

[0058] Examples of the polyfunctional (meth)acrylate monomers include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol hydroxypivalate di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified diphosphoric acid di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, isocyanurate di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl)isocyanurate, propionic acid-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate and other polyfunctional (meth)acrylates. Among these, dipentaerythritol-based (meth)acrylates are preferred, particularly dipentaerythritol hexa(meth)acrylate is preferred, and more preferably dipentaerythritol hexaacrylate is preferred. These may be used alone or in combination of two or more kinds.

[0059] On the other hand, examples of the (meth)acrylate prepolymers include prepolymers such as polyester acrylate-based, epoxy acrylate-based, urethane acrylate-based, polyol acrylate-based prepolymers. These prepolymers may be used alone or in combination of two or more kinds.

[0060] A polyester acrylate prepolymer can be obtained, for example, by esterifying the hydroxyl groups of a polyester oligomer having hydroxyl groups at both ends, obtained by condensation of a polycarboxylic acid and a polyhydric alcohol, with (meth)acrylic acid, or by esterifying the terminal hydroxyl groups of an oligomer obtained by adding an alkylene oxide to a polycarboxylic acid, with (meth)acrylic acid.

[0061] An epoxy acrylate prepolymer can be obtained, for example, by reacting an oxirane ring of a relatively low molecular weight bisphenol type epoxy resin or novolac type epoxy resin with (meth)acrylic acid to effect esterification.

[0062] The urethane acrylate prepolymer can be obtained, for example, by esterifying a polyurethane oligomer obtained by reacting a polyether polyol or polyester polyol with a polyisocyanate with (meth)acrylic acid.

[0063] The polyol acrylate prepolymer can be obtained, for example, by esterifying the hydroxyl groups of a polyether polyol with (meth)acrylic acid.

[0064] Among the above, urethane acrylate prepolymers (polyfunctional urethane (meth)acrylates) are preferred, and polyfunctional urethane acrylates are particularly preferred. Polyfunctional urethane (meth)acrylates are preferably used in combination with polyfunctional (meth)acrylate monomers, and particularly dipentaerythritol hexa(meth)acrylate.

[0065] When a polyfunctional urethane (meth)acrylate is used in combination with a polyfunctional (meth)acrylate monomer (particularly dipentaerythritol hexa(meth)acrylate), the amount of the polyfunctional urethane (meth)acrylate to 100 parts by mass of the polyfunctional (meth)acrylate monomer is preferably 50 parts by mass or more, more preferably 80 parts by mass or more, and even more preferably 95 parts by mass or more. The amount is preferably 150 parts by mass or less, more preferably 120 parts by mass or less, and even more preferably 105 parts by mass or less.

[0066] (1-2) Fine particles The fine particles may be either inorganic or organic, but inorganic fine particles are preferred because the change and rate of change in lightness L* before and after application are likely to be the values ​​described above. The shape of the fine particles, particularly inorganic fine particles, is preferably non-spherical, and more preferably irregular. The term "irregular" as used herein refers to a shape having many irregular corners or faces, rather than a regular shape such as a sphere or ellipse. The fine particles may be used alone or in combination of two or more types.

[0067] Examples of inorganic fine particles include fine particles made of metal oxides such as silica, aluminum oxide, zirconium oxide, titanium oxide, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), antimony oxide, and cerium oxide; and metal fluorides such as magnesium fluoride and sodium fluoride. Among the above, silica and aluminum oxide are preferred, silica is particularly preferred, and amorphous silica is more preferred. The surface of the inorganic fine particles may be chemically modified with an organic compound or the like.

[0068] The average particle size of the microparticles is preferably 0.1 μm or more, more preferably 0.4 μm or more, and even more preferably 0.6 μm or more. The average particle size of the microparticles is preferably 20 μm or less, more preferably 10 μm or less, more preferably 4 μm or less, and even more preferably 2 μm or less. The average particle size of the microparticles in this specification is a value measured by a laser diffraction scattering type particle size distribution measuring device (manufactured by Horiba, Ltd., product name "LA-920").

[0069] Regarding the particle size distribution of the fine particles, the coefficient of variation (CV value) of particle size represented by the following formula is preferably 10% or more, more preferably 50% or more, and even more preferably 80% or more. The CV value is preferably 300% or less, more preferably 200% or less, more preferably 150% or less, and even more preferably 100% or less. Coefficient of variation of particle size (CV value) (%) = (standard deviation particle size / average particle size) x 100 The coefficient of variation (CV value) of particle size is a value measured using a laser diffraction scattering type particle size distribution measuring device (manufactured by Horiba, Ltd., product name "LA-920").

[0070] The blending ratio of the above-mentioned microparticles to 100 parts by mass of the active energy ray-curable component is preferably 1 part by mass or more, more preferably 6 parts by mass or more, and even more preferably 12 parts by mass or more. The blending ratio is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less. When the blending ratio of the microparticles is within the above range, the amount and rate of change in the lightness L* before and after application are likely to be the values ​​described above.

[0071] (1-3) Surface conditioner The surface conditioner contained in the coating composition C is preferably a fluorine-based compound in order to obtain an optical member having excellent fingerprint resistance. Examples of the fluorine-based compound include fluoroalkyl carboxylates, fluoroalkyl phosphates, fluoroalkyl sulfonates, fluoroalkyl ammonium salts, fluoroalkyl ethylene oxide derivatives, fluoroalkenyl oligomer derivatives, and fluoroadamantane derivatives. Among them, from the viewpoint of fingerprint resistance, fluorine-based compounds having an adamantane skeleton are particularly preferred.

[0072] In addition, from the viewpoint of fingerprint resistance, the above-mentioned fluorine-based compound is preferably one having a polymerizable functional group, i.e., a fluorine-based compound containing a polymerizable functional group. Among them, from the viewpoint of fingerprint resistance, it is particularly preferable to use a fluorine-based compound containing a polymerizable functional group having an adamantane skeleton, i.e., a fluorine-containing adamantane derivative containing a polymerizable group. The surface conditioner may be used alone or in combination of two or more kinds.

[0073] The above-mentioned polymerizable group-containing fluorine-containing adamantane derivative is preferably represented by the following general formula (I). [ka]

[0074] In the above general formula (I), s is an integer of 1 to 15, preferably 1 to 12, t is an integer of 1 to 15, preferably 4 to 15, u is an integer of 0 to 14, preferably 0 to 4, and s+t+u=16. In addition, in the above general formula (I), F represents a fluorine atom.

[0075] In the above general formula (I), Y represents a group selected from a hydrogen atom, a hydrocarbon group, an alkoxy group, a halogen-substituted hydrocarbon group, a cyclic hydrocarbon group, a halogen-substituted cyclic hydrocarbon group, a hydroxyl group, a carboxyl group, and C=O formed by two Ys bonded to the same carbon atom together with the carbon atom.

[0076] Examples of the hydrocarbon group represented by Y include alkyl groups having 1 to 10 carbon atoms. The alkyl group may be linear, branched, or cyclic, and specific examples include methyl, ethyl, propyl, and butyl groups. Examples of the alkoxy group include methoxy and ethoxy groups. Examples of the halogen-substituted hydrocarbon group include the above-mentioned hydrocarbon groups in which one or more hydrogen atoms are substituted with halogen atoms, such as trifluoromethyl groups. Examples of the halogen atom include fluorine, chlorine, bromine, and iodine (the same applies below).

[0077] Examples of the cyclic hydrocarbon group represented by Y include a cycloalkyl group having 5 to 10 carbon atoms, specifically a cyclopentyl group, a methylcyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, an ethylcyclohexyl group, etc. Examples of the halogen-substituted cyclic hydrocarbon group include groups in which one or more hydrogen atoms of the above-mentioned cyclic hydrocarbon groups are substituted with halogen atoms, such as a fluorocyclopentyl group, a fluorocyclohexyl group, a trifluoromethylcyclopentyl group, a trifluoromethylcyclohexyl group, etc.

[0078] In the above general formula (I), Z 1 represents a group represented by the following general formula (II) or (III). [ka]

[0079] In the above general formula (II) or (III), R 1 ~R 4 each independently represents a hydrogen atom, a halogen atom, or an aliphatic hydrocarbon group which may contain a heteroatom and has 1 to 20 carbon atoms, preferably 1 to 15. n and m are integers of 0 or more.

[0080] R 1 ~R 4Among the aliphatic hydrocarbon groups having 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms, represented by the formula (I) and not containing a heteroatom, examples thereof include linear or branched alkyl groups having 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, octadecyl, and eicosyl.

[0081] R 1 ~R 4 Among the aliphatic hydrocarbon groups having 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms, those containing a hetero atom include -O- (a linear or branched alkyl group having 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms), -S- (a linear or branched alkyl group having 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms), -CO- (a linear or branched alkyl group having 1 to 19 carbon atoms, preferably 1 to 14 carbon atoms), -NH- (a linear or branched alkyl group having 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms), -N (a linear or branched alkyl group having 1 to 19 carbon atoms, preferably 1 to 7 carbon atoms). 2 Examples of such skeletons include:

[0082] Specific examples of the aliphatic hydrocarbon group containing a heteroatom and having 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms, include a methoxy group, an ethoxy group, a butoxy group, a hydroxymethyl group, a hydroxyethyl group, a methylthio group, an ethylthio group, a methylamino group, a dimethylamino group, an ethylamino group, and a diethylamino group.

[0083] In the above general formula (II), n is an integer of 0 or more, for example, an integer of 0 to 20, preferably an integer of 0 to 10, and more preferably 0, 1, 2, 3, 4 or 5.

[0084] In the above general formula (III), m is an integer of 0 or more, for example, an integer of 0 to 20, preferably an integer of 0 to 10, more preferably 0, 1, 2, 3, 4 or 5, and particularly preferably 0 or 1.

[0085] In the above general formula (I), X 1 represents a polymerizable group represented by the following general formula (IV), (V) or (VI). [ka]

[0086] In the above general formula (IV), R 5 represents a hydrogen atom, a methyl group, or a trifluoromethyl group. 6 represents a hydrocarbon group having 1 to 5 carbon atoms. Examples of the hydrocarbon group having 1 to 5 carbon atoms include an alkyl group and an alkoxy group. The alkyl group may be linear, branched, or cyclic, and specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and a pentyl group. Examples of the alkoxy group include a methoxy group and an ethoxy group.

[0087] As the above-mentioned fluorine-containing adamantane derivative having a polymerizable group, 1-perfluoroadamantyl methacrylate, perfluoro-1,3-bis(acryloxyethoxy)adamantane and perfluoro-1,3-adamantanediol dimethacrylate are particularly preferred.

[0088] The above polymerizable group-containing fluorine-containing adamantane derivative has X 1 Since the polymerizable group, for example, a reactive (meth)acrylate group, reacts with the active energy ray-curable component as the base material upon irradiation with active energy rays to form an integrated hard coat layer 12. With this hard coat layer 12, the amount and rate of change in lightness L* before and after application tend to reach the above-mentioned values, and the physical properties are highly durable.

[0089] Examples of commercially available fluorine-based surface conditioners include the Megafac F series, Megafac R series, and Megafac RS series manufactured by DIC Corporation; the Futergent series manufactured by NEOS Corporation; FC-4430 and FC-4432 manufactured by 3M Japan Limited; and the Surflon series manufactured by AGC Seimi Chemical Co., Ltd.

[0090] The blending ratio of the above surface conditioner to 100 parts by mass of the active energy ray curable component is preferably 0.01 parts by mass or more, particularly preferably 0.08 parts by mass or more, and more preferably 0.12 parts by mass or more. The blending ratio is preferably 1 part by mass or less, particularly preferably 0.6 parts by mass or less, and more preferably 0.2 parts by mass or less. When the content of the surface conditioner is within the above range, the amount and rate of change in lightness L* before and after application tend to be the values ​​described above.

[0091] (1-4) Photopolymerization initiator When ultraviolet rays are used as the active energy rays for curing the active energy ray-curable component, it is preferable that the coating composition C contains a photopolymerization initiator. By containing the photopolymerization initiator in this way, the active energy ray-curable component can be polymerized efficiently, and the polymerization curing time and the irradiation amount of ultraviolet rays can be reduced.

[0092] Examples of such photopolymerization initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, and the like. Examples of the benzoxanthone include benzoxanthone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiary-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, etc. These may be used alone or in combination of two or more.

[0093] The mixing ratio of the photopolymerization initiator to 100 parts by mass of the active energy ray-curable component is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 1 part by mass or more. The mixing ratio is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less.

[0094] (1-5) Other ingredients In addition to the above-mentioned components, the coating composition C may contain various additives, such as ultraviolet absorbers, antioxidants, light stabilizers, antistatic agents, silane coupling agents, antiaging agents, thermal polymerization inhibitors, colorants, surfactants, storage stabilizers, plasticizers, lubricants, defoamers, wettability improvers, and coating surface improvers.

[0095] (2) Thickness of the hard coat layer The thickness of the hard coat layer 12 is preferably 1 μm or more, particularly preferably 2 μm or more, and more preferably 3 μm or more. When the lower limit of the thickness of the hard coat layer 12 is the above value, the hard coat layer has the desired scratch resistance and pencil hardness. In addition, the thickness of the hard coat layer 12 is preferably 20 μm or less, particularly preferably 15 μm or less, and more preferably 10 μm or less. When the upper limit of the thickness of the hard coat layer 12 is the above value, the change amount and change rate of the lightness L* before and after coating are likely to be the above-mentioned value. Furthermore, from the viewpoint of the change amount and change rate of the lightness L* before and after coating being more preferable values, the thickness of the hard coat layer 12 is preferably 8 μm or less, particularly preferably 5 μm or less, and more preferably 4 μm or less.

[0096] 2. Manufacturing method of optical components The optical member 1 according to this embodiment can be produced by applying a coating liquid containing a coating composition for forming a hard coat layer 12, preferably coating composition C, and optionally a solvent, to a substrate 11 and curing the coating liquid to form the hard coat layer 12.

[0097] The solvent can be used for the purpose of improving the coatability, adjusting the viscosity, adjusting the solid content concentration, etc., and can be used without any particular limitation as long as it dissolves the curable component and disperses the fine particles.

[0098] Specific examples of the solvent include alcohols such as methanol, ethanol, isopropanol, butanol, and octanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate, butyl acetate, ethyl lactate, and γ-butyrolactone; ethers such as ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), diethylene glycol monobutyl ether (butyl cellosolve), and propylene glycol monomethyl ether; aromatic hydrocarbons such as benzene, toluene, and xylene; and amides such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. Among the above, ethers are preferred from the viewpoint of the dispersibility of the components in the coating liquid and the coatability, and propylene glycol monomethyl ether is particularly preferred.

[0099] The concentration (solid content concentration) of the coating liquid is preferably 10% by mass or more, particularly preferably 20% by mass or more, and more preferably 25% by mass or more. The concentration is preferably 60% by mass or less, particularly preferably 48% by mass or less, and more preferably 42% by mass or less. When the concentration of the coating liquid is in the above range, the in-plane uniformity of the coated surface (coating layer surface) is improved, and the reproducibility of the lightness L* is further improved.

[0100] The coating liquid of the coating composition may be applied by a conventional method, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, etc. After the coating liquid of the coating composition is applied, it is preferable to dry the coating film at 40 to 120°C for about 30 seconds to 5 minutes.

[0101] When the coating composition is active energy ray curable like coating composition C, the coating composition is cured by irradiating the coating film of the coating composition with active energy rays such as ultraviolet rays and electron beams. The ultraviolet ray irradiation can be performed by a high pressure mercury lamp, a fusion H lamp, a xenon lamp, etc., and the irradiation amount of the ultraviolet ray has an illuminance of 50 to 1000 mW / cm. 2 , light intensity 50~1000mJ / cm 2 In particular, from the viewpoint of improving the in-plane uniformity of the coated surface, and from the viewpoint of making it easier to set the amount and rate of change in L* before and after coating to the desired value due to the improved reproducibility of the lightness L* resulting from the improved in-plane uniformity, an illuminance of 200 to 500 mW / cm is preferable. 2 , light intensity 200~500mJ / cm 2 On the other hand, electron beam irradiation can be carried out by an electron beam accelerator or the like, and the dose of the electron beam is preferably about 10 to 1000 krad.

[0102] 3. Physical properties of optical components (1) Haze value The haze value of the optical member 1 according to this embodiment is preferably 30% or less, more preferably 20% or less, and particularly preferably 15% or less. If the haze value is 30% or less, it is suitable for use as a display. On the other hand, when antiglare properties are imparted to the optical member 1 or the hard coat layer 12, the haze value is preferably 3% or more, more preferably 4.5% or more, and particularly preferably 5.4% or more. The haze value is a value measured in accordance with JIS K7136-2000.

[0103] (2) Total light transmittance The total light transmittance of the optical member 1 according to this embodiment is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. If the total light transmittance is 70% or more, it is suitable for use as a display. The upper limit of the total light transmittance is not particularly limited, but is usually preferably 100%, more preferably 96% or less, and especially preferably 92% or less. The total light transmittance is a value measured in accordance with JIS K7361-1:1997.

[0104] (3) Arithmetic mean surface roughness (Ra) The arithmetic mean surface roughness (Ra) of the surface of the hard coat layer 12 of the optical member 1 according to this embodiment is preferably 0.6 μm or less, more preferably 0.3 μm or less, and even more preferably 0.15 μm or less. If the arithmetic mean surface roughness (Ra) is 0.6 μm or less, it is suitable for use as a display. On the other hand, when the hard coat layer 12 is to be given antiglare properties, the arithmetic mean surface roughness (Ra) is preferably 0.01 μm or more, more preferably 0.03 μm or more, and even more preferably 0.08 μm or more. In this specification, the arithmetic mean surface roughness (Ra) is determined from a roughness curve measured using a contact type roughness meter in accordance with JIS B0601-1994.

[0105] (4) Image clarity The total value of image clarity (%) of the optical combs of 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm measured for the optical member 1 according to this embodiment is preferably 200 or more, more preferably 250 or more, and even more preferably 300 or more. This improves image visibility as a display. On the other hand, when antiglare properties are imparted to the optical member 1 or the hard coat layer 12, the total value of image clarity is preferably 450 or less, more preferably 405 or less, and even more preferably 360 or less.

[0106] Here, the image clarity is measured by passing the amount of parallel light rays transmitted through a test specimen through an optical comb having a transmitting portion and a light-shielding portion. The smaller the width (comb width) between the transmitting portion and the light-shielding portion of the optical comb, the higher the image clarity. The image clarity is measured according to the transmission method of JIS K7374:2007.

[0107] (5) Contact angle (5-1) Contact angle with water (water contact angle) The water contact angle of the surface of the hard coat layer 12 of the optical member 1 according to this embodiment is preferably 45° or more as a lower limit, particularly preferably 55° or more, and more preferably 65° or more. This makes it difficult for fingerprints to adhere to the hard coat layer 12, and fingerprints that have adhered can be easily wiped off. On the other hand, the upper limit of the water contact angle is not particularly limited, but is preferably 90° or less, more preferably 85° or less, particularly preferably 80° or less, and more preferably 75° or less.

[0108] The water contact angle means the angle between the tangent of the droplet at the contact part of the hard coat layer surface and the hard coat layer surface when the droplet is placed on the hard coat layer surface and the angle including the droplet. The details of the method for measuring the water contact angle are as shown in the test examples described later.

[0109] (5-2) Contact angle with oleic acid (contact angle with oleic acid) The lower limit of the oleic acid contact angle on the surface of the hard coat layer 12 of the optical member 1 according to this embodiment is preferably 10° or more, more preferably 15° or more, and even more preferably 20° or more. This makes it difficult for fingerprints to adhere to the hard coat layer 12, and makes it easy to wipe off any fingerprints that do adhere. On the other hand, the upper limit of the oleic acid contact angle is not particularly limited, but is preferably 50° or less, more preferably 40° or less, and even more preferably 30° or less.

[0110] The oleic acid contact angle refers to the angle between the tangent of a droplet of oleic acid at the contact portion of the droplet with the surface of the hard coat layer when the droplet is placed on the surface of the hard coat layer, and the surface of the hard coat layer, the angle being on the side including the droplet. The details of the method for measuring the oleic acid contact angle are as shown in the test examples described later.

[0111] (6) Scratch resistance The hard coat layer 12 of the optical member 1 according to this embodiment is formed by applying a 250 g / cm 3 coating of #0000 steel wool. 2 It is preferable that the hard coat layer 12 is rubbed 10 times back and forth over a distance of 10 cm with a load of 100 g without any scratches. By having such scratch resistance as evaluated by the steel wool hardness, it is possible to prevent the hard coat layer 12 from being scratched when the optical member 1 is used on the surface of a touch panel.

[0112] (7) Pencil hardness The pencil hardness of the hard coat layer 12 of the optical member 1 according to this embodiment is preferably 2H or more. When the hard coat layer 12 has such a pencil hardness, the surface of the optical member 1 has sufficient hardness, and therefore, when the optical member 1 is used as the surface of a touch panel, for example, it can exhibit excellent surface protection properties.

[0113] The above-described embodiments are described for the purpose of facilitating understanding of the present invention, and are not described for the purpose of limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0114] For example, the surface of the optical member 1 to which the diluted oleic acid is applied does not have to be flat. However, it is preferable to apply the diluted oleic acid evenly. EXAMPLES

[0115] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0116] Hard coat films to be evaluated were produced according to the following Production Examples 1 to 6. [Production Example 1] A coating composition was obtained by mixing 50 parts by mass of dipentaerythritol hexaacrylate (representing a solid content equivalent value. The same applies to other components below), 50 parts by mass of multifunctional urethane acrylate (manufactured by Arakawa Chemical Industries, product name "Beamset 575CB"), 17 parts by mass of silica fine particles (average particle size 0.8 μm, CV value 93%, refractive index 1.46, amorphous), 3 parts by mass of α-hydroxyphenyl ketone as a photopolymerization initiator, and 0.15 parts by mass of a polymerizable group-containing fluorine-containing adamantane derivative (manufactured by Neos, product name "Ftergent 602A") as a surface conditioner. The coating composition was diluted with propylene glycol monomethyl ether to prepare a coating liquid with a solid content concentration of 30% by mass.

[0117] The coating liquid obtained above was applied with a wire bar #12 to a polyethylene terephthalate film (manufactured by Toray Industries, product name "Lumirror U48", thickness: 125 μm) with easy-adhesion treatment applied to both sides as a base film, and dried at 70° C. for 1 minute. Next, ultraviolet rays were irradiated under a nitrogen atmosphere using an ultraviolet irradiation device (manufactured by iGraphics, product name "iGrantage ECS-401GX type") under the following conditions to form a hard coat layer with a thickness of 4 μm, and a hard coat film was obtained. <Ultraviolet irradiation conditions> Light source: High pressure mercury lamp Lamp power: 2kW Conveyor speed: 4.23m / min ·Illuminance: 240mW / cm 2 ·Light amount: 307mJ / cm 2

[0118] [Production Example 2] 100 parts by mass of dipentaerythritol hexaacrylate, 14 parts by mass of silica fine particles (average particle size 1.5 μm, CV value 83%, refractive index 1.46, amorphous), 3 parts by mass of α-hydroxyphenyl ketone as a photopolymerization initiator, and 0.15 parts by mass of a polymerizable group-containing fluorine-containing adamantane derivative (manufactured by Neos, product name "Ftergent 602A") as a surface conditioner were mixed to obtain a coating composition. The coating composition was diluted with propylene glycol monomethyl ether to prepare a coating liquid with a solid content concentration of 30% by mass. Using the obtained coating liquid, a hard coat film was produced in the same manner as in Production Example 1.

[0119] [Production Example 3] A coating composition obtained in the same manner as in Production Example 1 was diluted with propylene glycol monomethyl ether to prepare a coating liquid having a solid content concentration of 40 mass %. A hard coat film was produced using the obtained coating liquid in the same manner as in Production Example 1, except that the thickness of the hard coat layer was 6 μm.

[0120] [Production Example 4] A coating composition obtained in the same manner as in Production Example 1 was diluted with propylene glycol monomethyl ether to prepare a coating liquid having a solid content concentration of 35% by mass. A hard coat film was produced using the obtained coating liquid in the same manner as in Production Example 1, except that the thickness of the hard coat layer was 5 μm.

[0121] [Production Example 5] A coating composition was obtained by mixing 40 parts by mass of dipentaerythritol hexaacrylate, 60 parts by mass of reactive silica fine particles (silica fine particles having acryloyl groups on the surface, the average particle size of the silica fine particles before surface modification is 40 nm), 4 parts by mass of crosslinked polymethylmethacrylate fine particles (average particle size 1.5 μm, CV value 23%, refractive index 1.49, spherical), 0.2 parts by mass of a carboxyl group-containing polymer modified product (manufactured by Kyoeisha Chemical Co., Ltd., product name "Floren G-700") as a dispersant, 3 parts by mass of α-hydroxyphenyl ketone as a photopolymerization initiator, and 0.2 parts by mass of an acrylic modified polydimethylsiloxane (manufactured by BYK-Chemie, product name "BYK-3550") as a surface conditioner. The coating composition was diluted with propylene glycol monomethyl ether to prepare a coating liquid with a solid content concentration of 30% by mass. A hard coat film was produced in the same manner as in Production Example 1 using the obtained coating liquid.

[0122] [Production Example 6] 50 parts by mass of dipentaerythritol hexaacrylate, 50 parts by mass of multifunctional urethane acrylate (manufactured by Arakawa Chemical Industries, product name "Beamset 575CB"), 15 parts by mass of silica fine particles (average particle size 0.8 μm, CV value 93%, refractive index 1.46, amorphous), 3 parts by mass of α-hydroxyphenyl ketone as a photopolymerization initiator, and 5 parts by mass of acrylic modified polydimethylsiloxane (manufactured by BYK-Chemie, product name "BYK-3550") as a surface conditioner were mixed to obtain a coating composition. The coating composition was diluted with propylene glycol monomethyl ether to prepare a coating liquid with a solid content concentration of 30% by mass. Using the obtained coating liquid, a hard coat film was produced in the same manner as in Production Example 1.

[0123] [Reference Example] (Selection of Oleic Acid Concentration) Oleic acid (manufactured by Tokyo Chemical Industry Co., Ltd.; the same applies below) itself was used as Sample 1 (oleic acid concentration: 100% by mass). 4 g of ethanol was added to 1 g of oleic acid, and the diluted oleic acid solution obtained by completely dissolving the acid was used as Sample 2 (oleic acid concentration: 20% by mass). 99 g of ethanol was added to 1 g of oleic acid, and the diluted oleic acid solution obtained by completely dissolving the acid was used as Sample 3 (oleic acid concentration: 1% by mass). 99.8 g of ethanol was added to 0.2 g of oleic acid, and the diluted oleic acid solution obtained by completely dissolving the acid was used as Sample 4 (oleic acid concentration: 0.2% by mass). 99.9 g of ethanol was added to 0.1 g of oleic acid, and the diluted oleic acid solution obtained by completely dissolving the acid was used as Sample 5 (oleic acid concentration: 0.1% by mass).

[0124] Each of Samples 1 to 5 was attached using a fingerstall to the surface of the hard coat layer of the hard coat film obtained in Production Example 1. Meanwhile, an actual fingerprint was attached to the surface of the hard coat layer of the hard coat film obtained in Production Example 1.

[0125] The hard-coated films with each of Samples 1 to 5 attached thereto were compared visually with the hard-coated films with actual fingerprints attached thereto. In addition, the hard-coated films with each of Samples 1 to 5 attached thereto and the hard-coated films with actual fingerprints attached thereto were wiped off with a nonwoven fabric wiper (manufactured by Asahi Kasei Corporation, product name "Bencotto S-2"). The ease of wiping was compared between each of Samples 1 to 5 and the actual fingerprints. The results are shown in Table 1.

[0126] [Table 1]

[0127] The results in Table 1 show that the degree of adhesion to the hard coat film (adhesion) and the ease of wiping off from the hard coat film (wipeability) of a diluted oleic acid solution with an oleic acid concentration of 0.2% by mass are equivalent to actual fingerprints.

[0128] [Test Example 1] (Measurement of haze value and total light transmittance) The haze value (%) and total light transmittance (%) of the hard coat film produced in each production example were measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "NDH-5000") in accordance with JIS K7136:2000 and JIS K7361-1:1997, respectively. The results are shown in Table 2.

[0129] [Test Example 2] (Measurement of surface roughness) The arithmetic mean surface roughness (Ra; unit μm) of the hard coat layer surface of the hard coat film produced in each production example was obtained from a roughness curve measured using a contact type roughness meter (manufactured by Mitutoyo Corporation, product name "SV3000S4") in accordance with JIS B0601-1994. The results are shown in Table 2.

[0130] [Test Example 3] (Measurement of image clarity) For the hard-coated films produced in each manufacturing example, an image clarity tester (manufactured by Suga Test Instruments, product name "ICM-10P") was used to measure the image clarity (%) of five types of optical combs (comb widths: 0.125mm, 0.25mm, 0.5mm, 1.0mm and 2.0mm) in accordance with the transmission method of JIS K7374:2007, and the total value was calculated as the image clarity. The results are shown in Table 2.

[0131] [Test Example 4] (Contact angle measurement) (1) Measurement of water contact angle The water contact angle on the surface of the hard coat layer of the hard coat film produced in each production example was measured under the following conditions using a fully automatic contact angle measuring instrument (manufactured by Kyowa Interface Science Co., Ltd., product name "DM-701"). Pure water was used as the water. The results are shown in Table 2. ·Environmental temperature: 23℃ Water droplet volume: 2μl ·Measurement time: 3 seconds after dropping Image analysis method: θ / 2 method

[0132] (2) Measurement of contact angle of oleic acid The contact angle of oleic acid on the surface of the hard coat layer of the hard coat film produced in each production example was measured under the following conditions using a fully automatic contact angle measuring instrument (manufactured by Kyowa Interface Science Co., Ltd., product name "DM-701"). The oleic acid used was that manufactured by Tokyo Chemical Industry Co., Ltd. The results are shown in Table 2. ·Environmental temperature: 23℃ Oleic acid drop volume: 2μl ·Measurement time: 3 seconds after dropping Image analysis method: θ / 2 method

[0133] [Test Example 5] (Evaluation of Scratch Resistance) The surface of the hard coat layer of the hard coat films produced in the Examples and Comparative Examples was wiped with 250 g / cm using #0000 steel wool. 2 The hard coat layer was rubbed 10 times back and forth over a distance of 10 cm with a load of 0.01 mm. The surface of the hard coat layer was visually observed under a three-wavelength fluorescent lamp, and the scratch resistance was evaluated according to the following criteria. The results are shown in Table 2. A: No injuries were found. B: The injury was confirmed.

[0134] [Test Example 6] (Measurement of pencil hardness) The pencil hardness of the hard coat layer surface of the hard coat films produced in the Examples and Comparative Examples was measured in accordance with JIS K5600 using an electric pencil scratch hardness tester (manufactured by Yasuda Seiki Seisakusho, product name "No. 553-M1"). The results are shown in Table 2.

[0135] [Test Example 7] (Evaluation of fingerprint resistance) (1) Preparation of evaluation samples Using an acrylic transparent double-sided adhesive sheet (manufactured by Lintec Corporation, product name "OPTERIA MO-3006C", refractive index: 1.49, haze: <1.0%), the substrate film side of the hard coat film manufactured in each manufacturing example was bonded to a black acrylic plate (L*3.42, a*-0.17, b*0.40), and this was used as an evaluation sample.

[0136] (2) Sensory evaluation A fingerprint was attached to the surface of the hard coat layer of the evaluation sample obtained above. The attached fingerprint was then visually observed under a three-wavelength fluorescent lamp (1000 lux.) and the visibility of the fingerprint was evaluated according to the following criteria. A rating of 3 or higher is considered to be good. The results are shown in Table 2. 5: Fingerprints are very hard to notice 4. Fingerprints are less noticeable 3: Fingerprints are slightly noticeable 2: Fingerprints are noticeable 1: Fingerprints are very visible

[0137] (3) Evaluation using the brightness L* as an index before and after application of a diluted oleic acid solution First, the surface of the hard coat layer of the evaluation sample obtained above was measured for lightness L* (lightness L* before coating) defined by the CIE1976 L*a*b* color system under the following conditions using a simultaneous photometric spectrophotometer (manufactured by Nippon Denshoku Industries Co., Ltd., product name "SE6000"). The results are shown in Table 2. <Measurement conditions> Light source: C light source Measurement method: Reflection measurement Measurement area: φ30mm (circular shape with a diameter of 30mm)

[0138] On the other hand, 0.2 g of oleic acid was added to 99.8 g of ethanol to completely dissolve it, and this was used as an oleic acid dilution solution. The obtained oleic acid dilution solution was applied to the surface of the hard coat layer of the evaluation sample obtained above with a wire bar #2, and naturally dried at 23°C and 50% RH to form an oleic acid layer.

[0139] The lightness L* of the surface of the evaluation sample on which the oleic acid layer was formed (lightness L* before and after application) was measured in the same manner as described above. The results are shown in Table 2.

[0140] Next, the change amount ΔL* was calculated by subtracting the lightness L* before application from the lightness L* after application. The change rate (%) of the lightness L* was calculated according to the following formula. The results are shown in Table 2. Rate of change = {(L* after application - L* before application) / L* before application} x 100

[0141] [Table 2]

[0142] As can be seen from Table 2, by using the pre-coating lightness L* and the post-coating lightness L* as indicators, the correlation with the sensory evaluation is high, and the fingerprint resistance can be quantitatively evaluated. Furthermore, the hard coat films according to Production Examples 1 to 4 were excellent in fingerprint resistance.

[0143] [Test Example 8] (Reproducibility test of fingerprint resistance evaluation) Two other hard-coated films were produced in the same manner as in Production Example 1. The three hard-coated films were produced on different days. For each of the hard-coated films obtained, the fingerprint resistance evaluation was performed according to Test Example 7 to confirm the reproducibility. The results are shown in Table 3, with the hard-coated film of Production Example 1 as N=1, the second hard-coated film as N=2, and the third hard-coated film as N=3.

[0144] [Table 3]

[0145] As can be seen from Table 3, in all hard coat films, the amount of change ΔL* in lightness L* and the rate of change in lightness L* were within a certain range, and a correlation was obtained between the sensory evaluation and the amount of change ΔL* in lightness L* and the rate of change in lightness L*. In other words, the above-mentioned method for evaluating fingerprint resistance allowed the fingerprint resistance to be evaluated quantitatively and with high reproducibility. [Industrial Applicability]

[0146] The fingerprint resistance evaluation method according to the present invention is suitable for evaluating the fingerprint resistance of, for example, a touch panel, particularly a hard coat film located on the outermost layer of a touch panel. The optical member according to the present invention is suitable for, for example, a hard coat film located on the outermost layer of a touch panel. [Explanation of symbols]

[0147] 1...Optical components 11...Base material 12...Hard coat layer

Claims

[Claim 1] A hard coat film comprising a substrate and a hard coat layer on an outermost surface thereof, the hard coat film is disposed on an article on which fingerprints may be attached such that the hard coat layer is located on the outermost surface on which fingerprints may be attached, the hard coat layer is a cured product of a coating composition containing an active energy ray-curable component, fine particles, and a surface conditioner which is a fluorine-based compound; The mixing ratio of the surface conditioner to 100 parts by mass of the active energy ray-curable component is 0.01 parts by mass or more and 0.2 parts by mass or less. A hard coat film characterized by the above-mentioned.

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