JP2013029828A - Light-transmitting molding and antireflection article using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-transmitting molding excellent in scratch resistance and antireflection performance.SOLUTION: The light-transmitting molding has a fine rugged layer 11 with projections and recesses in a size of equal to or less than a wavelength of visible light, the layer comprising a cured product of an active energy ray-curable resin composition and formed on a surface of a light-transmitting substrate 10. The active energy ray-curable resin composition contains a polymeric compound comprising a (meth)acrylic monomer (A) having four or more functional groups and if necessary, a (meth)acrylic monomer (B) having three or more functional groups except for the monomer (A). A content percentage of polyalkylene glycol (PAG) in the (meth)acrylic monomer (A), which is expressed by formula (a): PAG=M(PAG)/[M(ACR)+M(PAG)]×100, is 50% or more and 87% or less. In the formula, PAG represents a content percentage (%) of polyalkylene glycol, M(PAG) represents a total chemical formula weight of the polyalkylene glycol structure moiety; and M(ACR) represents a total chemical formula weight of the (meth)acryloyl structure moiety.

Description

  The present invention relates to a light-transmitting molded article having excellent scratch resistance and antireflection performance, and an antireflection article using the same.

  In recent years, in the field of anti-reflection film, a structure with a nanometer-sized fine concavo-convex layer called “moss eye” that mimics the surface of moth eyes or lotus leaves (hereinafter referred to as “nano concavo-convex structure”) has been developed. (For example, Patent Document 1). Since this nanostructure has a fine concavo-convex layer, it is possible to exhibit antireflection performance due to a continuous change in refractive index and superhydrophobicity or superhydrophilicity due to a combination with resin characteristics.

  Since the nano uneven structure exhibits excellent antireflection performance, it can be used for various optical applications such as various display panels, lenses, show windows, automobile meter covers, and members for improving the light extraction rate of solar cells. Further, it can be used for applications such as mirrors and window materials whose visibility deteriorates due to adhesion of water droplets, and the effect of improving visibility due to super water-repellent performance and super hydrophilic performance can also be obtained.

  Patent Document 1 discloses a film having a nano uneven structure. However, coating unevenness may occur on the film surface due to the influence of the dilution solvent used in the active energy ray-curable resin composition when forming the nano uneven structure. On the other hand, Patent Document 2 proposes a solventless active energy ray-curable resin composition. However, the light transmissive article formed with this curable resin composition still has room for improvement in terms of scratch resistance.

  On the other hand, as a general method for improving the scratch resistance, a method of adding slip properties by adding silicone oil as a surface conditioner to a curable resin composition (for example, Patent Document 3), a polyfunctional acrylate monomer There is a method to be used (for example, Patent Document 4).

Japanese Patent No. 4156415 International Publication No. 2008/096872 Pamphlet JP 2000-234073 A Japanese Patent No. 4318577

  Since the nano concavo-convex structure has a unique surface structure, it is difficult to impart scratch resistance by the same method as that for a smooth surface. For example, the method of blending a surface conditioner such as silicone oil as in Patent Document 3 cannot sufficiently satisfy the required scratch resistance. In addition, the adhered dirt may be difficult to remove due to the influence of the surface conditioner.

  In addition, in the method using the polyfunctional monomer ethylene oxide-modified compound of Patent Document 4, peeling failure such as cracking may occur when peeling from the mold. In addition, the projections of the nano uneven structure may break due to contact with a hard member, and the antireflection performance may deteriorate. Furthermore, when there is too much ethylene oxide, a phenomenon in which the protrusions of the nano uneven structure come close to each other, and the film may become cloudy.

  As described above, with the conventional general technique for improving the scratch resistance, it has been difficult to satisfactorily improve the scratch resistance of the molded article exhibiting the antireflection performance by the nano uneven structure.

  The present invention has been made to solve such problems. That is, an object of the present invention is to provide a light-transmitting molded article excellent in scratch resistance and antireflection performance.

  The present inventors have found that the cured product derived from the crosslinked structure of the polyfunctional (meth) acrylic monomer having a (meth) acryloyl structure and the flexibility of the cured product of the (meth) acrylic monomer having a polyalkylene glycol structure. Focusing on the properties, it has been found that the use of a monomer having these two structures in a specific ratio is very effective in imparting scratch resistance and flexibility, and the present invention has been completed.

That is, the present invention relates to a light transmissive molding having a light transmissive substrate and a fine uneven layer made of a cured product of an active energy ray-curable resin composition formed on at least one surface of the light transmissive substrate. Body,
The polymerizable compound contained in the active energy ray-curable resin composition has a polyalkylene glycol content (PAG) in the (meth) acrylic monomer (A) represented by the following formula (a) of 50% or more and 87. % Is a light-transmitting molded article containing a tetrafunctional or higher functional (meth) acrylic monomer (A).

PAG = M (PAG) / [M (ACR) + M (PAG)] × 100 (a)
PAG: polyalkylene glycol content (%),
M (PAG): total chemical formula amount of the polyalkylene glycol structural moiety,
M (ACR): Total chemical formula amount of (meth) acryloyl structure portion The present invention is an antireflection article using the above light-transmitting molded article.

  According to the present invention, by using a specific monomer having a (meth) acryloyl structure and a polyalkylene glycol structure in a specific ratio, a light transmissive molded article having a fine uneven layer excellent in scratch resistance and antireflection performance. Can provide. This light-transmitting molded product has low reflectivity over the entire visible light wavelength region, and exhibits excellent scratch resistance that does not cause scratches in the steel wool scratch test. As an article, it is very useful for applications such as various displays, lenses, and window materials.

It is typical sectional drawing which shows an example of the light-transmitting molded object of this invention.

  The active energy ray-curable resin composition used in the present invention is, for example, a resin composition that undergoes a polymerization reaction and cures when irradiated with active energy rays such as electron beams, ultraviolet rays, and visible rays. This active energy ray-curable resin composition is composed of a polymerizable compound having a radical polymerizable site such as a (meth) acryloyl group or a vinyl group, a polymerization initiator for initiating a polymerization reaction, and an organic solvent or a surface active as necessary. Consists of auxiliary agents such as agents.

  The polymerizable compound contained in the active energy ray-curable resin composition is a tetrafunctional or higher functional (meth) acrylic monomer (A) having at least one polyalkylene glycol structure in the molecule, and a (meth) acrylic monomer ( The polyalkylene glycol content (PAG) in A) is 50% or more and 87% or less.

  Here, the polyalkylene glycol structure is a molecular structure (—R—O—) n [n is an average number of repetitions] consisting of a repeating unit (—R—O—) [R is an alkylene group] of the molecular structure of alkylene glycol. Means. The polyalkylene glycol structure (—R—O—) n may be a molecular structure in which a plurality of single types of repeating units are linked, or may be a molecular structure in which a plurality of types of repeating units are linked together. Good. The average number of repeats means an average value obtained by dividing the total number of repeats by the number of polyalkylene glycol structures when a plurality of polyalkylene glycol structures having different numbers of repeats exist in one molecule.

  This (meth) acrylic monomer (A) has at least one (meth) acryloyl group and a compound having four or more radical polymerizable sites such as (meth) acryloyl group or vinyl group in one molecule. It is. In particular, it is preferable that all the polymerizable sites in the molecule are (meth) acryloyl groups, that is, have four or more (meth) acryloyl groups. “(Meth) acryloyl group” means “acryloyl group and / or methacryloyl group”, and “(meth) acrylate” means “acrylate and / or methacrylate”.

  In the (meth) acrylic monomer (A), the PAG represented by the formula (a) is 50% or more and 87% or less. Further, the PAG is preferably 55% or more and 83% or less, and more preferably 70% or more and 80% or less. By setting the PAG to 50% or more, high scratch resistance can be expressed. Further, if the PAG is 87% or less, the Martens hardness and the elastic modulus derived from the crosslink density of the light-transmitting molded product can be maintained satisfactorily. Can be prevented and light transmittance can be improved.

  As the (meth) acrylic monomer (A), a compound in which a (meth) acryloyl group is bonded to the hydroxyl part of a polyol compound having four or more hydroxyl groups via a polyalkylene glycol structure, so-called (meth) acrylic monomer alkylene Preference is given to using oxide-modifying compounds. Moreover, the alkylene oxide modified compound of urethane (meth) acrylate and the alkylene oxide modified compound of epoxy (meth) acrylate can also be used. The (meth) acrylic monomer (A) may be used alone or in combination of two or more. In particular, an ethylene oxide-modified compound (compound having a polyethylene glycol structure) is preferable because it makes it easy to remove attached dirt by wiping with water.

  The unit (—R—O—) of the molecular structure of the alkylene glycol of the (meth) acrylic monomer (A) is preferably 5 or more in terms of imparting the flexibility of the polyalkylene glycol structure. From the viewpoint of achieving both a crosslinking density and flexibility, the number of repetitions is preferably 2 to 4.

Specific examples of the tetrafunctional (meth) acrylic monomer (A) include pentaerythritol tetra (meth) acrylate EO-modified compounds, PO-modified compounds, EO / PO-modified compounds, butylene oxide-modified compounds, ditrimethylolpropane tetra Examples include EO-modified compounds, PO-modified compounds, EO / PO-modified compounds, and butylene oxide-modified compounds of (meth) acrylate. Specific examples of the pentafunctional or higher functional (meth) acrylic monomer (A) include dipentaerythritol hexa (meth) acrylate EO-modified compounds, PO-modified compounds, EO / PO-modified compounds, and butylene oxide-modified compounds. . “EO” means “ethylene oxide” and “PO” means “propylene oxide”. The “EO-modified compound” means a compound having a block structure (—CH ₂ —CH ₂ —O—) n of an ethylene oxide unit, and the “PO-modified compound” means a block structure (—CH ₂ of propylene oxide unit). It means a compound having —CH (CH ₃ ) —O—) n.

  The (meth) acrylic monomer (A) is particularly represented by the following general formula (1)

[In the formula (1), R _{1 to} R ₆ are H or CH ₃ , and 1 to q are integers satisfying 12 ≦ l + m + n + o + p + q ≦ 48. ]
(An EO-modified compound of dipentaerythritol hexa (meth) acrylate) and / or the following general formula (2)

[In the formula (2), R _{7 to} R ₁₀ are H or CH ₃ , and r to u are integers satisfying 8 ≦ r + s + t + u ≦ 32. ]
It is preferable that it is a compound represented by (EO-modified compound of pentaerythritol tetra (meth) acrylate).

  The active energy ray-curable resin composition may further contain a (meth) acrylic monomer (B) having three or more functions other than the (meth) acrylic monomer (A) together with the (meth) acrylic monomer (A) described above. preferable. By using this (meth) acrylic monomer (B) in combination, the scratch resistance is further improved.

  This (meth) acrylic monomer (B) has at least one (meth) acryloyl group and a compound having three or more radical polymerizable sites such as (meth) acryloyl group and vinyl group in one molecule. It is a compound other than the (meth) acrylic monomer (A). In particular, it is preferable that all polymerizable sites in the molecule are (meth) acryloyl groups, that is, three or more (meth) acryloyl groups. Trifunctional to 9 functional (meth) acrylic monomers are preferred.

  As the (meth) acrylic monomer (B), it is preferable to use a (meth) acrylic monomer in which a (meth) acryloyl group is bonded to the hydroxyl group of a polyol compound having three or more hydroxyl groups. Urethane (meth) acrylate and epoxy (meth) acrylate can also be used. The (meth) acrylic monomer (B) may be used alone or in combination of two or more. Moreover, the alkylene oxide modified compound of a (meth) acryl monomer can also be used. In terms of maintaining good Martens hardness and elastic modulus derived from the crosslinking density of the light-transmitting molded article, and further preventing white turbidity due to a phenomenon in which protrusions of the concavo-convex structure snuggle together, improving light transmittance ( The unit (—R—O—) of the molecular structure of the alkylene glycol of the (meth) acrylic monomer (B) preferably does not form a repeating structure, that is, the repeating number is 1. On the other hand, the average repeating number of the alkylene glycol structure of the (meth) acrylic monomer (B) is preferably 5 or more from the viewpoint of imparting the flexibility of the polyalkylene glycol structure. The (meth) acrylic monomer (B) may be used alone or in combination of two or more.

  Specific examples of the trifunctional (meth) acrylic monomer (B) include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and isocyanuric acid tri (meth) acrylate. Specific examples of the tetrafunctional (meth) acrylic monomer (B) include pentaerythritol tetra (meth) acrylate and ditrimethylolpropane tetra (meth) acrylate. Specific examples of the pentafunctional or higher functional (meth) acrylic monomer (B) include dipentaerythritol hexa (meth) acrylate. Further, urethane (meth) acrylate obtained by reacting a polyol compound, an isocyanate compound, and a (meth) acrylate having a hydroxyl group may be used. Further, a mixture obtained by reacting trimethylolethane, succinic acid and acrylic acid at a molar ratio of 2/4 may be used. Among these, from the viewpoint of polymerization reactivity, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ditrimethylolpropane (meth) acrylate, dipentaerythritol hexa (meth) acrylate and EO-modified compounds thereof are preferable. .

  Of 100 parts by weight of the polymerizable compound contained in the active energy ray-curable resin composition, the content of the (meth) acrylic monomer (A) is preferably 50 parts by mass or more and 100 parts by mass or less, and 50 parts by mass or more and 95 parts by mass. More preferably, it is 55 parts by weight or more and 80 parts by weight or less, and most preferably 60 parts by weight or more and 75 parts by weight or less. If it is 50 mass parts or more, the abrasion resistance and transparency of a light-transmitting molded object can be made favorable.

  When the (meth) acrylic monomer (B) is used in combination, the content of the (meth) acrylic monomer (B) is 5 parts by mass or more out of 100 parts by weight of the polymerizable compound contained in the active energy ray-curable resin composition. 50 mass parts or less are preferable, 20 mass parts or more and 45 mass parts or less are more preferable, and 25 mass parts or more and 40 mass parts or less are especially preferable. If it is 5 parts by mass or more, the effect of improving the scratch resistance resulting from the hard coat property of the (meth) acrylic monomer (B) itself and the flexibility of the polyalkylene glycol structure can be obtained. Moreover, if it is 50 mass parts or less, the toughness of hardened | cured material is maintained and it can prevent that the peeling defect from a stamper by the hardness becoming high too much, or the protrusion of an uneven | corrugated | grooved part breaks, and a reflectance falls. .

  The polymerizable compound contained in the active energy ray-curable resin composition is substantially composed of the (meth) acrylic monomer (A) or the (meth) acrylic monomer (A) and the (meth) acrylic monomer (B) described above. Configured. Here, “substantially constituted” does not mean that it contains no components other than the (meth) acrylic monomer (A) and / or the (meth) acrylic monomer (B), and is about several parts by mass. If so, other monomer components may be contained. Preferably, the (meth) acrylic monomer (A) is used alone or only two (meth) acrylic monomers (A) and (meth) acrylic monomers (B) are used.

  The active energy ray-curable resin composition is usually added with a polymerization initiator that generates radicals that are cleaved by irradiation with active energy rays to initiate a polymerization reaction. Examples of active energy rays include electron beams, ultraviolet rays, and visible rays. In general, ultraviolet rays are used from the viewpoint of apparatus cost and productivity.

  There is no restriction | limiting in particular in the kind of this polymerization initiator. Specific examples thereof include benzophenone, 4,4-bis (diethylamino) benzophenone, 2,4,6-trimethylbenzophenone, methyl orthobenzoylbenzoate, 4-phenylbenzophenone, t-butylanthraquinone, 2-ethylanthraquinone, 2,4. -Thioxanthones such as diethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 1-hydroxycyclohexyl-phenyl ketone Acetophenones such as 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone Benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl Examples include acylphosphine oxides such as pentylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, methylbenzoylformate, 1,7-bisacridinylheptane, and 9-phenylacridine.

  A polymerization initiator may be used individually by 1 type, and may use 2 or more types together. In particular, it is preferable to use two or more types having different absorption wavelengths. Moreover, you may use together thermal polymerization initiators, such as persulfates, such as potassium persulfate and ammonium persulfate, peroxides, such as a benzoyl peroxide, and an azo initiator, as needed.

  The proportion of the polymerization initiator is preferably 0.01 parts by mass or more and 10 parts by mass or less, more preferably 0.1 parts by mass or more and 5 parts by mass or less, and more preferably 0.2 parts by mass or more with respect to 100 parts by mass of the polymerizable compound. 3 parts by mass or less is particularly preferable. If it is 0.01 mass part or more, the sclerosis | hardenability of a resin composition and the mechanical physical property of the hardened | cured material resulting from the sclerosis | hardenability can be made favorable. If it is 10 parts by mass or less, it is possible to prevent adverse effects and coloring on the elastic modulus and scratch resistance of the cured product due to the remaining unreacted initiator.

  For the active energy ray-curable resin composition, a release agent, a lubricant, a plasticizer, an antioxidant, an antistatic agent, a light stabilizer, an ultraviolet absorber, a flame retardant, a flame retardant aid, and a polymerization agent, if necessary. You may mix | blend well-known additives, such as an inhibitor, a filler, a silane coupling agent, a coloring agent, a reinforcement | strengthening agent, an inorganic filler, and an impact modifier.

  The mixing conditions when mixing the polymerizable compound, the polymerization initiator, and, if necessary, the additive are not particularly limited. For example, the stirring time may be 1 hour or more and 10 hours or less, and the stirring temperature may be room temperature or more and 80 ° C. or less.

The Martens hardness of the fine concavo-convex layer of the light transmissive molded article of the present invention is preferably 15 N / mm ² or more. More preferably 20 N / mm ² or more, further preferably 30 N / mm ² or more. If it is 15 N / mm ² or more, a phenomenon in which the protrusions of the fine concavo-convex structure are close to each other is unlikely to occur, and thus whitening or cloudiness is not visible on the surface of the light-transmitting molded body.

The light-transmitting molded body of the present invention is a light-transmitting molded body having a load of 25 gf / cm ² using a 20 mm square indenter and steel wool # 0000 in an environment of a temperature of 23 ° C. and a humidity of 50% Rh. It is preferable that the number of scratches generated when the scratch resistance test for reciprocal rubbing is performed is 0 to 10 or less. Within this range, scratch resistance can be sufficiently provided.

  The light-transmitting molded product of the present invention is obtained by forming a fine uneven layer made of a cured product of the active energy ray-curable resin composition described above on at least one surface of a light-transmitting substrate.

  The light transmissive substrate may be any material that transmits light, and the material is not particularly limited. Examples of the material for the light transmissive substrate include methyl methacrylate (co) polymer, polycarbonate, styrene (co) polymer, methyl methacrylate-styrene copolymer, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, and polyester. , Polyamide, polyimide, polyether sulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polyurethane, and glass. The active energy ray-curable resin composition can be cured alone, but is generally cured on a light-transmitting substrate and integrated with the light-transmitting substrate.

  The shape and manufacturing method of the substrate are not particularly limited. For example, an injection molded body, an extrusion molded body, and a cast molded body can be used. The shape may be a sheet shape, a film shape, or other three-dimensional shapes. Furthermore, the surface of the substrate may be coated or corona treated for the purpose of improving properties such as adhesion, antistatic properties, scratch resistance, and weather resistance. In particular, in order to improve the adhesion between the active energy ray-curable resin composition and the light-transmitting substrate, it is preferable to use a light-transmitting substrate having an easy-adhesion layer on the surface.

  FIG. 1 is a schematic cross-sectional view showing an example of a light-transmitting molded article of the present invention. The light-transmitting molded body shown in this figure is a fine concavo-convex layer comprising a light-transmitting substrate 10 and a cured product of an active energy ray-curable resin composition formed on the upper surface of the light-transmitting substrate 10. 11. The fine concavo-convex layer 11 is formed with a nano concavo-convex structure in which fine convex portions 12 and concave portions 13 having a size equal to or smaller than the wavelength of visible light are alternately repeated. Visible light generally refers to light having a wavelength of 380 to 780 nm, and the size equal to or smaller than the visible light wavelength is a distance between adjacent convex portions 12 or concave portions 13 (protrusion width 15 in the drawing) of 380 nm or less. Means that. The height 14 of the unevenness is not particularly limited, but is preferably 60 nm or more, more preferably 90 nm or more from the viewpoint of antireflection characteristics. The fine concavo-convex layer 11 may be formed on the whole or a part of one side or both sides of the light transmissive substrate 10.

  The uneven shape of the fine uneven layer is not particularly limited. For example, in order to obtain an antireflection function that achieves both low reflectivity and low wavelength dependency by continuously increasing the refractive index from the air to the material surface, it is conical. A structure such as a pyramid shape, a bell shape, or the like in which the occupation ratio of the cross-sectional area when cut on the film surface continuously increases is preferable. Further, the fine projections may be formed by uniting finer protrusions.

  As a method for forming a fine uneven layer, for example, an active energy ray-curable resin composition is disposed between a stamper having a fine uneven structure and a light-transmitting substrate, and cured by active energy ray irradiation, and the cured product is obtained. A method of obtaining a cured product layer (fine concavo-convex layer) to which the fine concavo-convex structure is transferred by peeling the stamper from the layer is preferable.

  The manufacturing method of the stamper used in the above method is not particularly limited. For example, an electron beam lithography method, a laser beam interference method, an anodizing method, or the like can be used. For example, a mold having a fine concavo-convex layer can be produced by applying a photoresist film on a suitable support substrate, exposing it to light using ultraviolet laser, electron beam, X-ray or the like, and developing it. This mold can also be used as a stamper. Further, the support substrate can be selectively etched by dry etching through the photoresist layer, and the resist layer can be removed to form a fine relief structure directly on the support substrate surface.

  It is also possible to use anodized porous alumina as a stamper. For example, aluminum may be anodized at a predetermined voltage using oxalic acid, sulfuric acid, phosphoric acid or the like as an electrolytic solution to form a pore structure of 20 to 200 nm, and this may be used as a stamper. In this method, high-purity aluminum is anodized at a constant voltage for a long time, and then the oxide film is removed and then anodized again to form extremely highly regular pores in a self-organized manner. It has been known. Further, in the second anodic oxidation step, a fine uneven structure having a triangular or bell-shaped cross section can be formed by combining the anodizing treatment and the hole diameter enlarging treatment.

  Alternatively, a replica mold may be produced from an original mold having a fine concavo-convex structure by electroforming or the like and used as a stamper.

  The shape of the stamper is not particularly limited, and may be a flat plate shape or a roll shape. In particular, a roll-shaped stamper is preferable from the viewpoint of productivity because a fine uneven layer can be transferred continuously.

Examples of active energy rays used for polymerization / curing include electron beams, ultraviolet rays, and visible rays. In particular, ultraviolet rays are preferable. Examples of the lamp that irradiates ultraviolet rays include a high-pressure mercury lamp, a metal halide lamp, and an electrodeless UV lamp (various bulbs) manufactured by Fusion. What is necessary is just to determine an ultraviolet irradiation amount suitably according to the absorption wavelength and addition amount of the polymerization initiator in an active energy ray curable resin composition. If the curing is insufficient, the scratch resistance of the fine uneven layer may be impaired. Moreover, when there is too much irradiation amount, coloring of hardened | cured material and deterioration of a transparent substrate may be caused. Particularly preferably be cured by the integrated quantity of light of 400~4000mJ / cm ^2, and more preferably cured at a cumulative light quantity of 400~2000mJ / cm ^2. The irradiation intensity is not particularly limited, but is preferably suppressed to an output that does not cause deterioration of the light-transmitting substrate.

  The light-transmitting molded article of the present invention includes, for example, antireflection articles (antireflection films, antireflection films, antireflection sheets, and other antireflection members), optical waveguides, relief holograms, lenses, polarization separation elements, and the like. It can be used for optical articles and cell culture sheet applications. It is particularly suitable for use as an antireflection article. As the antireflection article, for example, an image display device such as a liquid crystal display device, a plasma display panel, an electroluminescence display, a cold cathode tube display device, an antireflection film used on the surface of a lens, a show window, a spectacle lens, Examples thereof include an antireflection film and an antireflection sheet. When used in an image display device, an antireflection film may be affixed on the outermost surface, may be molded as a member that will be the outermost surface, or may be molded as a front plate.

  Hereinafter, the present invention will be described in more detail with reference to examples. In the following description, “part” means “part by mass”. Each physical property was evaluated according to the following method.

<Abrasion resistance: Steel wool test>
Using a reciprocating abrasion tester (manufactured by Shinto Kagaku Co., Ltd., model name HEIDON Type: 30S), steel wool (# 0000) is attached to a 20 mm square indenter, and the load is applied in an environment of temperature 23 ° C. and humidity 50% Rh. The light-transmitting molded body was rubbed 10 times under the condition of 25 gf / cm ² . Thereafter, black paper was placed on the back surface of the light-transmitting molded body, the number of scratches generated on the light-transmitting molded body was confirmed, and visual evaluation was performed according to the following criteria. When the evaluation is A, the scratch resistance is sufficient, and when the evaluation is B, the scratch resistance is good.
“A”: 0 to 10 scratches.
“B”: The number of scratches exceeds 10 and is within 20
“C”: scratches are present on the entire surface of the indenter, or the entire surface is white and cloudy (including changes in appearance such as a decrease in light transmission other than the scratches).

<Antireflection: Reflectivity>
Using a spectrophotometer U-3300 manufactured by Hitachi, measure the relative reflectance between wavelengths of 380 nm and 780 nm, using a spectrophotometer U-3300 manufactured by Hitachi, The reflectance at 550 nm was evaluated according to the following criteria.
“◯”: 4.9% or less.
"X": It exceeds 4.9%.

<Fingerprint wiping: water wiping>
The surface opposite to the fine uneven structure surface (front surface) of the fine uneven layer is attached to a black acrylic resin plate (manufactured by Mitsubishi Rayon Co., Ltd., Acrylite EX # 502, 50 mm × 60 mm) via an optical adhesive layer. An article was prepared by attaching artificial fingerprint liquid (evaluation dispersion described in Japanese Patent No. 3799025) to the concavo-convex structure surface.
While applying a force of about 1 kgf / cm ^{2 with} a fingertip, the micro concavo-convex structure surface was reciprocated 10 times with a wiper (Nippon Paper Crecia Co., Ltd., Keidry Wiper 132-S) impregnated with 1.0 cc of tap water, The appearance of the article surface was evaluated.
○: The fingerprint was completely removed.
Δ: Fingerprints are almost inconspicuous, but the color when a fluorescent lamp is reflected is slightly different (the fingerprints are not completely removed).
X: A fingerprint remains clearly.

<Fingerprint wiping: dry wiping>
The surface opposite to the fine uneven structure surface (front surface) of the fine uneven layer is attached to a black acrylic resin plate (manufactured by Mitsubishi Rayon Co., Ltd., Acrylite EX # 502, 50 mm × 60 mm) via an optical adhesive layer. An article was prepared by attaching artificial fingerprint liquid (evaluation dispersion described in Japanese Patent No. 3799025) to the concavo-convex structure surface.
While applying force with the fingertip (about 3 kgf / cm ² ), the fine concavo-convex structure surface was reciprocated 40 times with a dry wiper (Nippon Paper Crecia Co., Ltd., Keidry Wiper 132-S), and then the appearance of the article surface was evaluated. .
○: The fingerprint was completely removed.
Δ: Fingerprints are almost inconspicuous, but the color when a fluorescent lamp is reflected is slightly different (the fingerprints are not completely removed).
X: A fingerprint remains clearly.

<Appearance: Transparency (cloudiness)>
The surface opposite to the fine concavo-convex structure surface (front surface) of the fine concavo-convex layer is attached to a black acrylic resin plate (manufactured by Mitsubishi Rayon Co., Ltd., Acrylite EX # 502, 50 mm × 60 mm) through the optical adhesive layer. The appearance of the article was evaluated as described in.
○: When a white LED light source is irradiated from an oblique direction, the surface is uniform and slight whitening or cloudiness is not observed.
Δ: The surface is uniform and white turbidity is not recognized under the fluorescent lamp in the room, but whitening and white turbidity are observed when the white LED light source is irradiated from an oblique direction.
X: Whitening and cloudiness are recognized even under indoor fluorescent lamps.

<Resin physical properties: Martens hardness and elastic modulus>
The resin compositions used in Examples and Comparative Examples are sandwiched between two glass slides (76 × 52 mm, thickness about 1 mm) with a spacer having a thickness of about 200 μm, and an integrated light quantity of 1200 mJ / cm using a high-pressure mercury lamp. It was cured by irradiating with ultraviolet rays with energy of ² . The slide glass on one side is peeled off, and the Martens hardness and elastic modulus of the cured resin surface are measured using an ultra-micro hardness tester (Fischer Instruments, trade name: Fisher Scope HM2000), ISO-14577. The measurement was performed under the following measurement conditions by a method based on -1.
Indenter shape: Vickers indenter (a = 136 °),
Measurement environment: temperature 23 ° C, relative humidity 50%,
Maximum test load: 100 mN
Loading speed: 100 mN / 10 seconds,
Maximum load creep time: 10 seconds,
Unloading speed: 100 mN / 10 seconds.

<PAG content ratio of resin composition>
PAG content [%] = [P (monomer 1) × PAG (monomer 1) + P (monomer 2) × PAG (monomer 2) +... + P (monomer n) × PAG (monomer n)] / 100,
PAG content: polyalkylene glycol content (%)
PAG (monomer 1): PAG of monomer 1 (%),
P (monomer 1): mass fraction (%) of monomer 1 in the composition.
(However, monomer 1, monomer 2... Monomer n are all monomers constituting the resin composition containing (meth) acrylic monomer (A), (meth) acrylic monomer (B), and other monomers). )

(Production of stamper)
Aluminum having a purity of 99.99% was mirror polished by feather polishing and electrolytic polishing in a perchloric acid / ethanol mixed solution (1/4 volume ratio).
(A) Process:
This aluminum plate was anodized in a 0.3 M oxalic acid aqueous solution for 30 minutes under conditions of a direct current of 40 V and a temperature of 16 ° C.
(B) Process:
The aluminum plate on which the oxide film was formed in the above step was immersed in a 6% by mass phosphoric acid / 1.8% by mass chromic acid mixed aqueous solution for 6 hours to remove the oxide film.
(C) Process:
This aluminum plate was anodized for 30 seconds in a 0.3 M oxalic acid aqueous solution under the conditions of a direct current of 40 V and a temperature of 16 ° C.
(D) Process:
The aluminum plate on which the oxide film was formed in the above step was immersed in 5% by mass phosphoric acid at 32 ° C. for 8 minutes to carry out pore diameter expansion treatment.
(E) Process:
The steps (c) and (d) were repeated 5 times in total to obtain anodized porous alumina having substantially conical pores with a period of 100 nm and a depth of 180 nm.

  The obtained anodized porous alumina was washed with deionized water, and then water on the surface was removed by air blow, and the fluorine-based release material (trade name Optool DSX, manufactured by Daikin Industries, Ltd.) was adjusted to a solid content of 0.1% by mass. Thus, it was immersed in a solution diluted with a diluent (trade name HD-ZV, manufactured by Harves Co., Ltd.) for 10 minutes and air-dried for 20 hours to obtain a stamper having pores formed on the surface.

<Example 1>
As component (A), 70 parts of EO-modified compound of dipentaerythritol hexaacrylate [Daiichi Kogyo Seiyaku Co., Ltd., trade name DPHA-12EO], as component (B), ethoxylated pentaerythritol tetraacrylate (Shin Nakamura Chemical) 30 parts by Kogyo Co., Ltd., trade name: NK Ester ATM-4E), 1.0 parts of 1-hydroxy-cyclohexyl-phenyl-ketone (trade name: IRGACURE 184, made by Ciba Japan Co., Ltd.) and bis. 0.5 part of (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Ciba Japan Co., Ltd., trade name IRGACURE819), release agent (manufactured by Sakai Kogyo Co., Ltd., trade name Mold With INT-1856) ) An active energy ray-curable resin composition consisting of 0.1 part was prepared.

The total chemical formula amount (M (PAG)) of the polyalkylene glycol structure (—C ₂ H ₄ O—) n part in the component (A) used here is 44 × 12 = 528, and the acryloyl structure (CH ₂ = CHCO-) The total formula amount (M (ACR)) of the moiety is 55 × 6 = 330, and the polyalkylene glycol content (PAG) is 528 / (330 + 528) × 100≈61.5 (%) It is.

A few drops of the above active energy ray-curable resin composition was dropped on a stamper, and the surface was covered with a 188 μm-thick polyethylene terephthalate film (trade name A-4300, manufactured by Toyobo Co., Ltd.). Next, the film was cured by irradiating ultraviolet rays with an energy of 1200 mJ / cm ² using a high-pressure mercury lamp from the film side. Subsequently, the film and the stamper were peeled off to obtain a light-transmitting molded body having a fine uneven layer with an interval between adjacent protrusions or recesses of 100 nm and a height of 180 nm.

<Examples 2 to 17 and Comparative Examples 1 to 7>
A light-transmitting molded article was produced in the same manner as in Example 1 except that the compounds shown in Table 1 and Table 2 were used as the polymerizable compound.

  Tables 1 and 2 show the evaluation results of the above examples and comparative examples.

Abbreviations in the table are as follows.
"A": number of acryloyl groups,
"N": average number of repeating structures derived from alkylene glycol,
"PAG": polyalkylene glycol content (%),
"DPHA-12EO": EO-modified compound of dipentaerythritol hexaacrylate [Daiichi Kogyo Seiyaku Co., Ltd., trade name DPHA-12EO-modified, R _{1 to} R ₆ in general formula (1) are all H and ethylene The total number of repeating units (l + m + n + o + p + q) of the molecular structure of glycol is 12, and the average number of repeating units of polyethylene glycol structure is 2 (= 12/6)]
“DPHA-18EO”: EO-modified compound of dipentaerythritol hexaacrylate [Daiichi Kogyo Seiyaku Co., Ltd., trade name DPHA-18EO-modified, R _{1 to} R _{6 in} the general formula (1) are all H and ethylene A compound in which the total number of repeating units (l + m + n + o + p + q) of the molecular structure of glycol is 18, the average number of repeating units of polyethylene glycol structure is 3 (= 18/6)],
“DPHA-24EO”: EO-modified compound of dipentaerythritol hexaacrylate [Daiichi Kogyo Seiyaku Co., Ltd., trade name DPHA-24EO-modified, R _{1 to} R ₆ in general formula (1) are all H and ethylene The total number of repeating units of the molecular structure of glycol (l + m + n + o + p + q) is 24, and the average number of repeating units of polyethylene glycol structure is 4 (= 24/6)]
“DPHA-30EO”: EO-modified compound of dipentaerythritol hexaacrylate [Daiichi Kogyo Seiyaku Co., Ltd., trade name DPHA-30EO-modified, R _{1 to} R ₆ in general formula (1) are all H and ethylene The total number of repeating units (l + m + n + o + p + q) of the molecular structure of glycol is 30, and the average number of repeating units of polyethylene glycol structure is 5 (= 30/6)]
"ATM-4E": ethoxylated pentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name ATM-4E),
"DPHA": Dipentaerythritol hexaacrylate (manufactured by Toagosei Co., Ltd.)
"A-TMPT-6EO": EO-modified compound of trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., average number of repetitions of polyethylene glycol structure = 2),
"PE-4A": pentaerythritol tetraacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate PE-4A),
"ATM-35E": Ethoxylated pentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., a compound having a total number of repeating units of molecular structure of ethylene glycol of 35 and an average number of repeating polyethylene glycol structures of 8) .75 (= 35/4)),
"A-GLY-20E": ethoxylated glycerin triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., a compound having a total number of 20 repeating units of the molecular structure of ethylene glycol, and the average number of repeating polyethylene glycol structures = 6 .67 (20/3)),
"M260": polyethylene glycol (n = about 13) diacrylate (manufactured by Toagosei Co., Ltd.)
"A-1000": polyethylene glycol (n = 23) diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK-ester A-1000),
"9EG-A": polyethylene glycol (n = 9) diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light acrylate 9EG-A),
"HEA": hydroxyethyl acrylate,
“A-SA”: 2-acryloyloxyethyl succinate (manufactured by Shin-Nakamura Chemical Co., Ltd.).

<Evaluation>
As is apparent from the results in Table 1, the light transmissive molded products of Examples 1 to 7, 9, and 12 to 17 had good scratch resistance and low reflectance. Further, the light-transmitting molded bodies of Examples 8, 10, and 11 having a Martens hardness of less than 15 N / mm ² are within 20 pieces, which are inconspicuous in a part of the test part by a scratch resistance test. Minor scratches occurred. On the other hand, the light transmissive molded article of Comparative Example 1 containing no (meth) acrylic monomer (A) had more than 20 scratches in the scratch resistance test, and the entire scratch resistance test portion was clouded white. Similarly, Comparative Examples 2 and 4-7 which do not contain (meth) acrylic monomer (A), Comparative Example 3 which contains components other than (meth) acrylic monomer (A) and (meth) acrylic monomer (B), PAG In the light-transmitting molded article of Comparative Example 4 in which the content is less than 50% and Comparative Example 5 in which the number of functional groups of the (meth) acrylic monomer (B) is 3, many scratches are generated on the entire surface where the indenter hits. It was.

Moreover, the light-transmitting molded articles of Comparative Examples 4 and 5 containing only the (meth) acrylic monomer (B) having a small average number of repeating structures derived from alkylene glycol could not be removed by wiping with water.
Further, in Examples 8 to 11 in which the Martens hardness was relatively soft, although the scratch resistance was good, white turbidity due to a phenomenon in which the protrusions of the fine concavo-convex structure nestle was observed.
Moreover, the light-transmitting molded bodies of Examples 1 to 17 were able to be removed at a level where the fingerprints were not noticeable without being scratched by water wiping and dry wiping. Although the light-transmitting molded bodies of Comparative Examples 1 to 5 and 7 were inferior in scratch resistance, the fingerprints could be removed at a level where they were not noticeable by dry wiping or water wiping.

  The light-transmitting molded body of the present invention has various anti-reflection performance and high scratch resistance performance as a nano uneven structure, so that various display panels, lenses, show windows, automobiles that may be used outdoors. It can be used for optical applications such as cover glass for image sensors such as meter covers, rod lens arrays, fax machines, copiers, and scanners, contact glass for placing manuscripts for copiers, and members for improving the light extraction rate of spectacle lenses and solar cells. It is extremely useful industrially. It can also be used for mirrors and window materials that have poor visibility due to water droplets.

DESCRIPTION OF SYMBOLS 10 Light-transmitting base material 11 Fine concavo-convex layer 12 Convex part 13 Concave part 14 Convex height 15 Protrusion width

Claims (7)

A light-transmitting molded article having a light-transmitting substrate and a fine uneven layer made of a cured product of an active energy ray-curable resin composition formed on at least one surface of the light-transmitting substrate,
The polymerizable compound contained in the active energy ray-curable resin composition has a polyalkylene glycol content (PAG) in the (meth) acrylic monomer (A) represented by the following formula (a) of 50% or more and 87. %. A light-transmitting molded article that is a tetrafunctional or higher-functional (meth) acrylic monomer (A) that is not more than%.
PAG = M (PAG) / [M (ACR) + M (PAG)] × 100 (a)
PAG: polyalkylene glycol content (%),
M (PAG): total chemical formula amount of the polyalkylene glycol structural moiety,
M (ACR): Total chemical formula amount of (meth) acryloyl structure moiety   The light-transmitting molded article according to claim 1, wherein the active energy ray-curable resin composition further contains a trifunctional or higher functional (meth) acrylic monomer (B) other than the (meth) acrylic monomer (A).   The average number of repetitions of the structure in which the (meth) acrylic monomer (A) and / or the (meth) acrylic monomer (B) of the polymerizable compound contained in the active energy ray-curable resin composition is derived from alkylene glycol is 5 The light-transmitting molded article according to claim 1 or 2, which has one or more of the above polyalkylene glycol structures in a molecule. The (meth) acrylic monomer (A) is represented by the following general formula (1)

[In the formula (1), R _{1 to} R ₆ are H or CH ₃ , and 1 to q are integers satisfying 12 ≦ l + m + n + o + p + q ≦ 48. ]
And / or the following general formula (2)

[In the formula (2), R _{7 to} R ₁₀ are H or CH ₃ , and r to u are integers satisfying 8 ≦ r + s + t + u ≦ 32. ]
The light-transmitting molded article according to any one of claims 1 to 3, which is a compound represented by the formula: The light-transmitting molded article according to any one of claims 1 to 4, wherein the Martens hardness of the fine uneven layer is 15 N / mm ² or more. When a 20 mm square indenter and steel wool # 0000 are used in an environment of a temperature of 23 ° C. and a humidity of 50% Rh, and a scratch resistance test is performed in which a light-transmitting molded product is rubbed 10 times under a load of 25 gf / cm ^2. The light-transmitting molded article according to any one of claims 1 to 5, wherein there are no more than 0 to 10 scratches. An antireflection article using the light transmissive molded article according to claim 1.

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