JP2012141355A - Manufacturing method of optical member having fine rugged structure on surface thereof, and article thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable material which hardly causes optical anisotropy due to a warp and residual strain of a base material caused by heat evolution during curing and contraction of a curable material.SOLUTION: There is provided a manufacturing method of an optical member having a fine rugged structure on its surface, in which a space between a base material (A) composed of heat-resistant acrylic resin and a molding die (B) having a fine rugged structure on its surface is filled with a curable composition (C), and after (C) is cured by activation energy ray irradiation and/or heating, (B) is removed.

Description

  The present invention relates to a method for producing an optical member having a fine concavo-convex structure on the surface by nanoimprinting.

Reflection of sunlight, illumination, and the like at the interface in contact with air in optical parts and lenses used in various displays is often a problem because it causes a decrease in visibility. In general, AG (Anti-Glare) treatment, AR (Anti-Reflection) treatment, and the like are well known as devices for suppressing reflection on the surface of the optical member.
The AG process is a process in which irregularities are formed on the surface of the optical member by coating with fine particles, etc., and the reflected image is scattered by light scattering to blur the outline. In the AR treatment, a film having a refractive index different from that of the base material is applied on the surface of the base material with a thickness of about the wavelength of the light, thereby causing light interference and reducing the reflectance.

Another new antireflection technique is the addition of a moth eye structure. This is to form a ridge-shaped protrusion smaller than the wavelength of visible light on the surface of the optical member, so that the refractive index of the region between the base material portion and the air layer is the refractive index of the material forming the protrusion. And the intermediate refractive index of air. The refractive index of the intermediate region continuously changes within a distance shorter than the wavelength of visible light because the occupation ratio of the protrusion and air changes depending on the height. As a result, the interface between the air and the substrate is not recognized as an interface having a different refractive index, and reflection of visible light generated at the interface can be suppressed. (Non-Patent Document 1)
As a method for imparting such a moth-eye structure, there is a technique for transferring nanometer-sized irregularities engraved in a mold onto a substrate, so-called nanoimprint technique. In the nanoimprint technology, a thermoplastic substrate is softened by heating, and a mold is pressed onto the mold, then the mold is cooled, and then the mold is cooled, and the mold is pressed against the curable material applied on the substrate. There is a method of curing the curable material by applying an active energy ray or heating. In the latter nanoimprint technology, a UV nanoimprint technology using an active energy ray as a method of curing a curable material is a method in which a thin film of an ultraviolet curable resin is formed on a transparent substrate, a mold is pressed on the thin film, and then ultraviolet light is applied. Is formed on the substrate to form a thin film having an inverted moth-eye structure of the mold, which is preferable in terms of shortening the molding time compared to molding using heat. A method of providing an antireflection article by imparting a moth-eye structure to a transparent substrate by such a method is disclosed. (Patent Document 1)

JP2008-209540

OPTICA ACTA, 1982, Vol. 29, no. 7,993-1009

However, when a curable resin is applied to a film-like substrate and cured, there is a problem that optical anisotropy due to warping of the film or residual strain is likely to occur due to heat generation during curing or shrinkage of the curable material. Moreover, when it was going to improve the mold release property of curable resin, there existed a problem that the adhesiveness with a base material fell or a repellency was produced when apply | coated. On the other hand, when it was going to improve adhesiveness, there existed a problem that curable resin eroded the base-material surface and impaired smoothness and transparency.

  In order to solve the above-mentioned problems, a method is used in which a liquid curable composition (C) is filled between a base material (A) made of a heat-resistant acrylic resin and a mold (B) having a fine concavo-convex structure on the surface. This is a method for producing an optical member having a fine concavo-convex structure on the surface by removing (B) after curing (C) by energy beam irradiation and / or heating. Thereby, an optical member with small reflection and small warpage and residual strain can be obtained.

  Further, by making the absolute value of the difference in refractive index between the cured products (A) and (C) 0.1 or less, reflection at the interface between the cured products (A) and (C) is reduced, An optical member with less reflection can be manufactured.

  When the average period in the horizontal direction of the unevenness of (B) is equal to or less than the wavelength of visible light, an optical member with higher antireflection performance can be manufactured.

  Furthermore, by making the above (C) an acrylic curable composition, high productivity due to good curability, high throughput due to high releasability and mechanical strength, and efficient antireflection It becomes possible to manufacture an optical member having performance. Furthermore, even if it is applied on the base material (A) made of a heat-resistant acrylic resin, it is possible to produce an optical member having good base material adhesion, transparency and smoothness without causing repellency.

  As described above, according to the present invention, it is possible to efficiently manufacture an optical member with small reflection and small warpage and residual strain.

<Base material made of heat-resistant acrylic resin (A)>
The base material (A) in the present invention is made of a heat-resistant acrylic resin. The heat-resistant acrylic resin includes a heat-resistant acrylic polymer. The content of the heat-resistant acrylic polymer in the heat-resistant acrylic resin is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 95%. It is at least mass%.

In the present specification, the heat-resistant acrylic polymer includes a cyclic structure and a structural unit derived from a (meth) acrylic acid ester in the main chain, and the total of the structural unit derived from the cyclic structure and the (meth) acrylic acid ester is all. The polymer which is 50 mass% or more of a structural unit shall be pointed out.
In addition, “resin” in the present specification is a broader concept than “polymer”. The resin may be composed of, for example, one or two or more polymers, and if necessary, materials other than the polymer, for example, additives such as ultraviolet absorbers, antioxidants, fillers, compatibilizing agents, A stabilizer and the like may be included.

  As the ring structure of the main chain of the heat-resistant acrylic polymer, N-substituted maleimide such as cyclohexylmaleimide, methylmaleimide, phenylmaleimide, benzylmaleimide, or maleic anhydride is copolymerized to form a ring derived from N-substituted maleimide. A structure or a ring structure derived from an acid anhydride may be introduced, or a lactone ring structure, a glutaric acid anhydride structure, a glutarimide structure, a ring derived from an N-substituted maleimide in the main chain by a cyclization reaction after polymerization A structure or the like may be introduced. From heat resistance, lactone ring structure, cyclic imide structure (ring structure derived from N-alkyl-substituted maleimide, glutarimide ring, etc.) and cyclic acid anhydride structure (ring structure derived from maleic anhydride, glutaric anhydride, etc.) What has is preferable. A lactone ring structure, a glutarimide ring structure, and a glutaric anhydride structure are preferred because they can impart positive intrinsic birefringence to the resin and, as a result, can impart a positive retardation to the resulting optical film. Among these, those having a lactone ring structure in the main chain are particularly preferred from the viewpoint of optical properties such as wavelength dependency.

  The lactone ring structure of the main chain may be a 4- to 8-membered ring, but a 5- to 6-membered ring is more preferable, and a 6-membered ring is still more preferable in terms of structural stability. In addition, when the main chain lactone ring structure is a 6-membered ring, the synthesis yield is high in synthesizing the polymer before introducing the lactone ring structure into the main chain, and the content ratio of the lactone ring structure is high. The structure represented by the following general formula (1) is preferable from the viewpoint that a polymer is easily obtained and that the copolymerizability with a (meth) acrylic acid ester such as methyl methacrylate is good.

(In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom. Examples of the group include an alkyl group having 1 to 20 carbon atoms such as a methyl group, an ethyl group, and a propyl group; an unsaturated aliphatic hydrocarbon group having 1 to 20 carbon atoms such as an ethenyl group and a propenyl group. An aromatic hydrocarbon group having 1 to 20 carbon atoms, such as a phenyl group or a naphthyl group; one or more hydrogen atoms in the alkyl group, the unsaturated aliphatic hydrocarbon group and the aromatic hydrocarbon group; Is a group substituted with at least one group selected from a hydroxyl group, a carboxyl group, an ether group and an ester group.)
Although the content rate of a ring structure is not specifically limited, Usually, it is 5-90 mass%, 10-70 mass% is preferable, 10-60 mass% is more preferable, 10-50 mass% is further more preferable. When the content is excessively small, the heat resistance of a resin molded product obtained by molding a resin may be lowered, or the solvent resistance and surface hardness may be insufficient. On the other hand, when the said content rate becomes large too much, the moldability and handling property of resin will fall.

  Examples of acrylic resins having a lactone ring structure in the main chain include JP 2000-230016, JP 2001-151814, JP 2002-120326, JP 2002-254544, JP 2005-2005. Examples thereof include acrylic resins having a lactone ring structure described in Japanese Patent No. 146084.

  Examples of the acrylic resin having a glutarimide structure in the main chain include JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, JP-A-2006-328334, and JP-A-2006. Acrylic resins having a glutarimide structure described in Japanese Patent No. 337491, Japanese Patent Application Laid-Open No. 2006-337492, Japanese Patent Application Laid-Open No. 2006-337493, Japanese Patent Application Laid-Open No. 2006-337569, Japanese Patent Application Laid-Open No. 2007-009182, and the like. It is done.

  As the acrylic resin having a glutaric anhydride structure in the main chain, the glutaric anhydride structure described in JP-A-2006-283013, JP-A-2006-335902, JP-A-2006-274118 and the like is used. Acrylic resin that can be used.

  A known (meth) acrylic acid ester can be used as the heat-resistant acrylic polymer. The total content of the structural units derived from the (meth) acrylic acid ester of the heat-resistant acrylic polymer is preferably 10% by mass or more, more preferably 30% by mass or more, still more preferably 50% by mass or more, and even more particularly. Preferably it is 70 mass% or more.

  Examples of (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, and t-butyl (meth) acrylate. , N-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate , (Meth) acrylic acid 3-hydroxypropyl, (meth) acrylic acid 2,3,4,5,6-pentahydroxyhexyl, (meth) acrylic acid 2,3,4,5-tetrahydroxypentyl, etc. It is a structural unit derived from a monomer. The heat-resistant acrylic polymer particularly preferably has a methyl (meth) acrylate unit, and in this case, the optical properties and thermal stability of the molded product are improved. The heat-resistant acrylic polymer may have two or more of these structural units as (meth) acrylic acid ester units.

  The heat-resistant acrylic polymer may have a structural unit other than the (meth) acrylic acid ester unit. Such structural units include, for example, styrene, vinyl toluene, α-methylstyrene, α-hydroxymethylstyrene, α-hydroxyethylstyrene, acrylonitrile, methacrylonitrile, ethylene, propylene, 4-methyl-1-pentene, acetic acid. It is a structural unit derived from monomers such as vinyl, 2-hydroxymethyl-1-butene, methyl vinyl ketone, N-vinyl pyrrolidone, and N-vinyl carbazole. The acrylic polymer may have two or more of these structural units.

  When a cyclic structure is introduced into the main chain by a cyclization reaction, the heat-resistant acrylic polymer is preferably copolymerized with a monomer having a hydroxyl group or a carboxylic acid group at the time of polymerization. Specifically, as a monomer having a hydroxyl group, methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, isopropyl 2- (hydroxymethyl) acrylate, 2- (hydroxymethyl) acrylic Acid butyl, methyl 2- (hydroxyethyl) acrylate, methallyl alcohol, allyl alcohol, and (meth) acrylic acid units as monomers having a carboxylic acid group include, for example, acrylic acid, methacrylic acid, crotonic acid, Examples include structural units derived from monomers such as 2- (hydroxymethyl) acrylic acid and 2- (hydroxyethyl) acrylic acid. Two or more kinds of these monomers may be copolymerized. A monomer having a hydroxyl group or a carboxylic acid group changes to a ring structure by a cyclization reaction, but is derived from a monomer having an unreacted hydroxyl group or carboxylic acid group in an acrylic polymer having a ring structure in the main chain. A structural unit may be included.

  The heat-resistant acrylic polymer preferably has a weight average molecular weight of 10,000 to 500,000, more preferably 50,000 to 300,000.

  The heat-resistant acrylic resin preferably has thermoplasticity. The Tg (glass transition temperature) of the heat-resistant acrylic resin is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, still more preferably 115 ° C. or higher, and particularly preferably 120 ° C. or higher. Further, the upper limit value of Tg of the thermoplastic resin is not particularly limited, but is preferably 170 ° C. or less from the viewpoint of moldability and the like.

  The heat-resistant acrylic resin may contain an additive. Examples of additives include hindered phenol-based, phosphorus-based and sulfur-based antioxidants; light-resistant stabilizers, weather-resistant stabilizers, heat stabilizers and other stabilizers; reinforcing materials such as glass fibers and carbon fibers; phenyls UV absorbers such as salicylate, (2,2′-hydroxy-5-methylphenyl) benzotriazole, 2-hydroxybenzophenone; near infrared absorbers; tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide, etc. Flame retardants; Antistatic agents such as anionic, cationic and nonionic surfactants; Colorants such as inorganic pigments, organic pigments and dyes; Organic fillers and inorganic fillers; Anti-blocking agents; Resin modifiers; Agents, inorganic fillers, plasticizers, lubricants, antistatic agents, flame retardants, phase difference reducing agents, and the like.

  Although the content rate of the additive in heat-resistant acrylic resin is not specifically limited, Preferably it is 0-5 mass%, More preferably, it is 0-2 mass%, More preferably, it is 0-0.5 mass%.

  Examples of the ultraviolet absorber include benzophenone compounds, salicinate compounds, benzoate compounds, triazole compounds, and triazine compounds. Of these, triazine-based UV absorbers and triazole-based UV absorbers are preferred because they are highly compatible with amorphous thermoplastic resins, particularly acrylic resins, and have excellent absorption characteristics.

  These can be used alone or in combination of two or more. Although the compounding quantity of the said ultraviolet absorber is not specifically limited, It is preferable that it is 0.01-25 mass% in the layer which has a thermoplastic resin as a main component, More preferably, it is 0.05-10 mass%. If the amount added is too small, the contribution to improving the weather resistance is low, and if it is too large, the mechanical strength may be lowered or yellowing may be caused.

  The heat-resistant acrylic resin may contain other thermoplastic resins in addition to the heat-resistant acrylic polymer. Examples of other thermoplastic resins include olefin polymers such as polyethylene, polypropylene, ethylene-propylene copolymer, and poly (4-methyl-1-pentene); vinyl chloride, vinylidene chloride, chlorinated vinyl resins, and the like. Vinyl halide polymers; acrylic polymers such as polymethyl methacrylate; styrene polymers such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene block copolymer Polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polyamides such as nylon 6, nylon 66 and nylon 610; polyacetals; polycarbonates; polyphenylene oxides; I de; polyether ether ketone; polysulfones; polyethersulfones; polyoxyethylene benzylidene alkylene; polyamideimide; polybutadiene rubber, rubber-like polymer such as ABS resin or ASA resin containing an acrylic rubber. When a styrene polymer is contained, a film having a low retardation can be obtained by canceling the positive retardation of the acrylic polymer having a ring structure in the main chain with the negative retardation of the styrene polymer. . In the styrene polymer, a styrene-acrylonitrile copolymer is particularly preferable from the viewpoint of compatibility with the acrylic polymer. Moreover, since both a negative phase difference (or low phase difference) and a flexibility can be provided to an optical film, ABS resin and ASA resin are also preferable.

  The content ratio of the other thermoplastic resin in the heat-resistant acrylic resin is preferably 0 to 50% by mass, more preferably 0 to 40% by mass, further preferably 0 to 30% by mass, and particularly preferably 0 to 20% by mass. is there.

  In order to produce the heat-resistant acrylic resin, for example, a polymer and an additive are pre-blended with any suitable mixer such as an omni mixer, and then the obtained mixture is extruded and kneaded. In this case, the mixer used for extrusion kneading is not particularly limited, and for example, any suitable mixer such as an extruder such as a single screw extruder or a twin screw extruder or a pressure kneader may be used. Can do.

  The thickness of the base material (A) <hereinafter referred to simply as the base material (A)> comprising the heat-resistant acrylic resin in the present invention is not particularly limited, but the film strength is maintained particularly when used as an optical film for a flat panel display. However, it is desired to reduce the weight and thickness of the panel itself, and the thickness is preferably 10 to 200 μm, more preferably 15 to 150 μm, and still more preferably 20 to 100 μm.

  The Tg (glass transition temperature) of the substrate (A) in the present invention is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, still more preferably 115 ° C. or higher, and particularly preferably 120 ° C. or higher. Moreover, although an upper limit is not specifically limited, Preferably it is 180 degrees C or less. If Tg is lower than 100 ° C., warping or distortion may occur after molding.

  In the substrate (A) in the present invention, the in-plane retardation value (Re) at a wavelength of 589 nm is preferably 10 nm or less, more preferably 5 nm or less, and further preferably 3 nm or less. Further, the absolute value (| Rth |) of the thickness direction retardation value is preferably 10 nm or less, more preferably 5 nm or less, and further preferably 3 nm or less. The “phase difference value” is also referred to as a retardation value, or simply “phase difference” or “retardation”.

The in-plane retardation value (Re) here is
Re = (nx−ny) × d
The thickness direction retardation value (Rth) is
Rth = [(nx + ny) / 2−nz] × d
Defined. Nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the direction perpendicular to nx in the film plane, nz is the refractive index in the film thickness direction, and d is the film thickness (nm). . The slow axis direction is a direction in which the refractive index in the film plane is maximum.

  The substrate (A) in the present invention preferably has an ultraviolet-absorbing ability. For example, the transmittance of light having a wavelength of 380 nm is less than 30%, sometimes less than 20%, and further preferably less than 10%. . What is necessary is just to measure this transmittance | permeability based on prescription | regulation of JISK7361: 1997.

  The substrate (A) in the present invention preferably has a visible light transmittance. For example, the transmittance of light having a wavelength of 500 nm is preferably 80% or more, sometimes 85% or more, and more preferably 90% or more. The transmittance can be measured in the same manner as the transmittance of light having a wavelength of 380 nm.

  The base material (A) in the present invention is less colored, and the b value per 250 μm thickness is preferably 0.5 or less, more preferably 0.3 or less.

The substrate (A) in the present invention preferably has few appearance defects. Appearance defects are caused by raw materials such as resin, foreign substances mixed in the manufacturing process, bubbles during molding, die lines and scratches at the die and roll part during molding, filtration of raw materials with polymer filters, Possible measures include cleaning the manufacturing process and optimizing the molding conditions. Specifically, the number of defects in the film of the substrate (A) is preferably 1000 / m ² or less, more preferably 500 / m ² or less, with a particle size of 20 μm or more. The number is preferably 200 pieces / m ² or less, ideally 0 pieces / m ² .

The manufacturing method of the base material (A) in the present invention is not particularly limited, and a known manufacturing method is possible. By film-forming a thermoplastic resin (composition) containing a thermoplastic resin, fine particles, and other additives. can get. Examples of the film forming method include known film forming methods such as a melt extrusion method, a solution casting method (solution casting method), a calendar method, and a compression molding method. Among these, the melt extrusion method and the solution cast method (solution casting method) are preferable.

<Mold (B) having a fine uneven structure on the surface>
The molding die (B) <hereinafter simply referred to as the molding die (B)> having a fine concavo-convex structure on the surface of the present invention has a convex portion having an average height of 100 nm to 1000 nm or an average depth of 100 nm on at least one surface thereof. It is essential to have a recess of 1000 nm or less. Here, the convex portion refers to a portion protruding from the reference surface, and the concave portion refers to a portion recessed from the reference surface. The mold (B) of the present invention may have a convex portion or a concave portion on the surface thereof. Moreover, you may have both a convex part and a recessed part, Furthermore, they may connect and may have an uneven structure. In addition, what is necessary is just to use a concave-shaped shaping | molding die, when forming a convex shape on the surface of a molded product, and using a convex-shaped shaping | molding die, when shaping a concave shape on the surface of a molded product.
It is essential that the average height or depth of the convex portion and the concave portion from the reference surface is 100 nm or more and 1000 nm or less. The height or depth may not be constant, and the average value only needs to be within the above range, but preferably has a substantially constant height or a constant depth.
Whether it is a convex portion or a concave portion, the average height or average depth is preferably 150 nm or more, and particularly preferably 200 nm or more. Moreover, it is preferable that it is 600 nm or less, and it is especially preferable that it is 500 nm or less. If the average height or the average depth is too small, good optical properties may not be exhibited. If the average height or average depth is too large, production may be difficult. In the case where the convex part and the concave part are connected and have a wavy structure, the average length of the highest part (above the convex part) and the deepest part (below the concave part) may be 100 nm or more and 1000 nm or less. It is preferable for the same reason.
In the mold (B) of the present invention, the convex portion or the concave portion is arranged on the surface so that the average period in the horizontal direction with respect to at least the surface of the substrate (A) is 100 nm or more and 400 nm or less. It is essential. The convex part or the concave part may be arranged at random or may be arranged with regularity. In any case, it is preferable in terms of antireflection properties and transmission improvement properties that the convex portions or the concave portions are disposed substantially uniformly over the entire surface of the substrate (A). Further, it is only necessary that the average period be at least 100 nm to 400 nm in at least one direction, and the average period does not have to be 100 nm to 400 nm in all directions.
When the convex part or the concave part is arranged with regularity, as described above, if the average period in the horizontal direction with respect to the surface of the substrate (A) is arranged to be 100 nm or more and 400 nm or less, However, it is preferable that the period in the direction with the shortest period be 100 nm or more and 400 nm or less. That is, it is preferable that the period is in the above range when the direction having the shortest period is taken as one direction. Further, at that time, it is particularly preferable that the period is also set to be 100 nm or more and 400 nm or less in the direction perpendicular to the direction having the shortest period.
120 nm or more is preferable and the average period (“period” when there is regularity in the arrangement positions of the convex portions or the concave portions) is particularly preferably 150 nm or more. Moreover, 250 nm or less is preferable and 200 nm or less is especially preferable. If the average period is too short or too long, the antireflection effect may not be sufficiently obtained.
The area occupancy of the fine concavo-convex structure on the surface of the mold (B) of the present invention is preferably 40% or more, more preferably 60% or more, most preferably 80% or more per unit area of the reference surface. is there. If the area occupancy ratio of the fine concavo-convex structure is lower than 40%, the area of the flat portion increases and reflection may increase.
The number of fine irregularities on the surface of the mold (B) of the present invention is preferably 4 or more, more preferably 9 or more, and most preferably 16 or more per 1 μm ² of the reference surface. Is preferably 100 or less, more preferably 90 or less, and most preferably 80 or less. If the number of fine irregularities is too large or too small, the antireflection effect may not be sufficiently obtained.
There is no restriction | limiting in particular as a shape of the fine concavo-convex structure on the surface of the shaping | molding die (B) of this invention, According to the objective, it can select suitably. For example, when used for an antireflection coating, the shape of the surface fine concavo-convex structure of the molded product is an average refraction from the air interface to the substrate (A) depending on the shape of a cone, triangle pyramid, bell, etc. It is preferable to have a structure in which the rate changes continuously. Therefore, the shape of the fine concavo-convex structure on the surface of the molding die (B) required for this purpose requires a conical shape such as a conical shape, a triangular pyramid shape, or a bell shape. Among these, those with a fine concavo-convex structure having no directionality such as a conical shape, a triangular pyramid shape, and a bell shape are more preferable, and a continuous change in refractive index in the thickness direction is linear, such as a conical shape and a triangular pyramid shape. Some are particularly preferred.
The aspect ratio, which is a value obtained by dividing the height or depth by the average period, is not particularly limited, but 1 or more is preferable in terms of optical characteristics, 1.5 or more is particularly preferable, and 2 or more is more preferable. Moreover, 5 or less is preferable on a structure manufacturing process, and 3 or less is especially preferable. By polymerizing the (meth) acrylic polymerizable composition in the present invention, a structure having an aspect ratio of 1.5 or more can be formed for the first time. Accordingly, in order to exhibit the characteristics of the (meth) acrylic polymerizable composition in the present invention, the aspect ratio is preferably as large as possible, particularly preferably 1.5 or more, and further preferably 2 or more.
As the surface shape processing method of the mold (B) of the present invention, a semiconductor device or photomask manufacturing process can be used. The surface shape processing of the nanoimprint mold requires extremely high accuracy, and as a method to achieve this accuracy, dry etching is performed using a resist pattern formed on the surface of a silicon or quartz substrate by photolithography or electron beam lithography as a mask. There is a way to do it. By using this method, a pattern with a fine width of several tens of nm can be formed in an arbitrary shape.
Further, it is possible to use an electroforming process for manufacturing a duplicate product in which the concave and convex portions are reversed by plating, using a fine pattern of silicon, quartz or the like prepared by the above method as a master. As a result, a large number of molds such as nickel can be duplicated with one master mold, which is very advantageous economically.

<Curable composition (C)>
The curable composition (C) of the present invention is not particularly limited as long as it can be changed from a liquid to a solid by irradiation with active energy rays or heating to transfer the surface shape of the mold (B).
The curable composition (C) of the present invention preferably contains a reactive monomer, a reactive oligomer, a polymerization initiator and the like. Reactive components such as reactive monomers and reactive oligomers can be used with any reaction mechanism such as radical polymerizability, ionic polymerizability, and addition reactivity, but radical polymerizability from the viewpoint of reaction rate. Among them, a (meth) acrylic curable composition is preferable from the viewpoints of safety, variety of physical properties, and economy. Moreover, it is preferable to set it as a (meth) acrylic curable composition also from the point of adhesiveness with the base material (A) which consists of heat-resistant acrylic resin. Thereby, even if it does not perform special pretreatments such as corona discharge treatment and primer coating on the base material, it is possible to give a fine surface irregularity layer with good adhesion without causing repelling during coating.
The (meth) acrylic curable composition in the present invention is a composition containing 50% by mass or more of a compound having a (meth) acryloyl group.
Examples of the reactive monomer include (meth) acrylic acid esters, (meth) acrylamides, N-vinyl compounds, vinyl ethers, α, β-unsaturated compounds, epoxy compounds, oxetane compounds, and the like. Although it can be used, it is not necessarily limited to these.
Specific examples include methyl (meth) acrylate (meth) acrylic acid, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) Methoxyethyl acrylate, (meth) acrylic acid methoxypolyethylene glycol, (meth) acrylic acid, (meth) acrylic acid N, N-dimethylaminoethyl, (meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 3- Monofunctional (meth) acrylic acid esters such as hydroxypropyl; monofunctional (meth) acrylamides such as N, N-dimethyl (meth) acrylamide and N-methylol (meth) acrylamide; methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, 2-ethylhexyl vinyl ether Monofunctional vinyl ethers such as cyclohexyl vinyl ether, methoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether; monofunctional N-vinyl compounds such as N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylformamide, N-vinylacetamide; styrene, α -Monofunctional vinyl compounds such as methylstyrene and vinyl acetate; maleic anhydride, maleic acid, dimethyl maleate, diethyl maleate, fumaric acid, dimethyl fumarate, diethyl fumarate, monomethyl fumarate, monoethyl fumarate, itaconic anhydride Monofunctional α, β-unsaturated compounds such as acid, itaconic acid, dimethyl itaconate, methylenemalonic acid, dimethylmethylenemalonate, cinnamic acid, methyl cinnamate, crotonic acid, methyl crotonic acid; Monofunctional epoxy compounds such as ether, ethyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, cyclohexyl glycidyl ether, methoxyethyl glycidyl ether; 3-methyl-3-phenoxymethyl oxetane, 3-ethyl-3-phenoxymethyl Monofunctional oxetane compounds such as oxetane and 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane; trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, glycerol tri (meth) acrylate, etc. Polyfunctional (meth) acrylic acid esters; trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, etc. Functional vinyl ethers; polyfunctional α, β-unsaturated compounds such as divinylbenzene; ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, butylene glycol diglycidyl ether, hexanediol diglycidyl ether, bisphenol A Polyfunctional epoxy compounds such as alkylene oxide diglycidyl ether, bisphenol F alkylene oxide diglycidyl ether, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether; di [1-methyl (3-oxetanyl)] methyl ether, di [1 -Ethyl (3-oxetanyl)] methyl ether, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} Polyfunctional oxetane compounds such as benzene and bis {4-[(3-ethyl-3-oxetanyl) methoxy] methyl} benzyl ether can be used.
Further, a compound having a (meth) acryloyl group and a vinyl ether group in one molecule, a compound having a (meth) acryloyl group and an epoxy group in one molecule, and a compound having a (meth) acryloyl group and an oxetane group in one molecule It is also possible to use a different polymerizable monomer such as
Examples of the compound having (meth) acryloyl group and vinyl ether group in one molecule include 2-vinyloxyethyl (meth) acrylate, 3-vinyloxypropyl (meth) acrylate, and 1-methyl-2-vinyloxyethyl (meth) acrylate. 2-vinyloxypropyl (meth) acrylate, 4-vinyloxybutyl (meth) acrylate, 1-methyl-3-vinyloxypropyl (meth) acrylate, 1-vinyloxymethylpropyl (meth) acrylate, (meth ) 2-methyl-3-vinyloxypropyl acrylate, 3-methyl-3-vinyloxypropyl (meth) acrylate, 1,1-dimethyl-2-vinyloxyethyl (meth) acrylate, 3- (meth) acrylic acid 3- Vinyloxybutyl, 1-methyl-2-vinyloxypropyl (meth) acrylate, (meth) acrylic 2-vinyloxybutyl acid, 4-vinyloxycyclohexyl (meth) acrylate, 5-vinyloxypentyl (meth) acrylate, 6-vinyloxyhexyl (meth) acrylate, 4-vinyloxymethylcyclohexylmethyl (meth) acrylate , (Meth) acrylic acid p-vinyloxymethylphenylmethyl, (meth) acrylic acid 2- (vinyloxyethoxy) ethyl, (meth) acrylic acid 2- (vinyloxyisopropoxy) ethyl, (meth) acrylic acid 2- (Vinyloxyethoxy) propyl, 2- (vinyloxyethoxy) isopropyl (meth) acrylate, 2- (vinyloxyisopropoxy) propyl (meth) acrylate, 2- (vinyloxyisopropoxy) isopropyl (meth) acrylate , (Meth) acrylic acid 2- (vinyloxyethoxyethoxy) ) Ethyl, 2- (vinyloxyethoxyisopropoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxyisopropoxy) propyl (meth) acrylate, 2- (vinyloxyethoxyethoxy) isopropyl (meth) acrylate, (Meth) acrylic acid 2- (vinyloxyethoxyisopropoxy) isopropyl, (meth) acrylic acid 2- (vinyloxyethoxyethoxyethoxy) ethyl, (meth) acrylic acid polyethylene glycol monovinyl ether, (meth) acrylic acid polypropylene glycol mono Vinyl ether or the like can be used.
As a compound having a (meth) acryloyl group and an epoxy group in one molecule, glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, etc. can be used, and (meth) acryloyl in one molecule. As a compound having a group and an oxetane group, 3-ethyl-3-methacryloxyoxetane or the like can be used.
As the reactive oligomer, urethane (meth) acrylates, epoxy (meth) acrylates, polyester (meth) acrylates, silicone (meth) acrylates, and the like can be used, but are not particularly limited thereto. Absent.
The urethane (meth) acrylates are not particularly limited as long as they are (meth) acrylate compounds having a urethane bond in the molecule. For example, the position and number of urethane bonds and the position and number of (meth) acryl groups are particularly There is no limitation.
As a preferable chemical structure of urethane (meth) acrylates, a hydroxyl group and (preferably a plurality of) (meth) acrylic groups are included in the molecule with respect to a compound having (preferably a plurality of) isocyanate groups in the molecule. A compound having a structure obtained by reacting a compound having a compound, a compound having a plurality of hydroxyl groups with a diisocyanate compound or a triisocyanate compound, and an unreacted isocyanate group of the obtained compound to hydroxyethyl (meth) acrylate And the like having a structure obtained by reacting a compound having a hydroxyl group and a (meth) acrylic group in the molecule.
The epoxy (meth) acrylate is not particularly limited as long as it is a (meth) acrylate compound having a structure obtained by reacting an epoxy group with (meth) acrylic acid. For example, the position of the (meth) acrylic group The number is not particularly limited.
Preferred chemical structures of epoxy (meth) acrylates include diglycidyl ethers of polyoxyalkylene glycols such as polyethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether; glycerin diglycidyl ether and the like Glycerin glycidyl ethers; bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, diglycidyl ether of bisphenol A alkylene oxide modified products, diglycidyl ethers of bisphenol compounds such as bisphenol F diglycidyl ether, etc. Examples thereof include those having a structure to which (meth) acrylic acid is added.
The polyester (meth) acrylates are not particularly limited as long as they are (meth) acrylate compounds having a plurality of ester bonds in the molecule.
Preferable chemical structures of polyester (meth) acrylates include esterification reaction products of polyester polyol and (meth) acrylic acid obtained by condensation of polyhydric alcohol and polycarboxylic acid.
The silicone (meth) acrylates are not particularly limited as long as they are (meth) acrylate compounds having a plurality of siloxane bonds in the molecule.
As a preferable chemical structure of silicone (meth) acrylates, for example, a siloxane compound having a (meth) acryloyl group is condensed with a tetraalkoxysilane compound, a trialkoxysilane compound, a dialkoxysilane compound, a monotetraalkoxysilane compound, or the like. Is obtained.
As the polymerization initiator, a radical photopolymerization initiator, a thermal radical polymerization initiator, a cationic photopolymerization initiator, a thermal cationic polymerization initiator, and the like can be used, but are not particularly limited thereto.
As the radical photopolymerization initiator, the following compounds are suitable. For example, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1- Hydroxycyclohexyl phenyl ketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone, 2-hydroxy-2- Acetophenones such as methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer; benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether; benzophenone, o-ben Methyl ylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3 ', 4,4'-tetra (t-butylperoxylcarbonyl) benzophenone, 2,4,6-trimethyl Benzophenones such as benzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethylammonium chloride; 2 -Isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy) -3,4-dimethyl -9H-thioxan Thioxanthones such as down-9-Onmesokurorido. Among these, acetophenones, benzophenones, and acyl phosphine oxides are preferable. In particular, 2-hydroxy-2-methyl-1-phenylpropan-1-one and 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one are preferable.
As the thermal radical polymerization initiator, the following compounds are suitable. For example, methyl ethyl ketone peroxide, cyclohexanone peroxide, acetyl acetate peroxide, 1,1-bis (t-hexylperoxy) -cyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethyl Cyclohexane, 1,1-bis (t-butylperoxy) butane, diisopropylbenzene hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, lauroyl Peroxide, succinic acid peroxide, benzoyl peroxide, diisopropyl peroxydicarbonate, α, α'-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodeca Noate, t-hexylperoxypivalate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxyisopropylmonocarbonate, t- Butyl peroxyisobutyrate, t-butyl peroxymalate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxyacetate, t-butyl peroxybenzoate, bis (t- Butylperoxy) isophthalate, 2,5-dimethyl-2,5-bis (m-tolylperoxy) hexane, t-hexylperoxybenzoate, t-butyltrimethylsilyl peroxide, 3,3 ', 4,4' -Tetra (t-butylperoxycarbonyl) ben Organic peroxide initiators such as phenone and 2,3-dimethyl-2,3-diphenylbutane; 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobisisobutyronitrile 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis [2- (5-methyl-2-imidazoline) -2-yl) propane] dihydrochloride, 2,2′-azobis [2- (4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl) propane] dihydrochloride, 2,2 '-Azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] pro Onamide}, 2,2′-azobis (2-methylpropionamide), 2,2′-azobis (2,4,4-trimethylpentane), 2,2′-azobis (2-methylpropane), dimethyl 2, Azo initiators such as 2-azobis (2-methylpropionate), 4,4'-azobis (4-cyanopentanoic acid), 2,2'-azobis [2- (hydroxymethyl) propionitrile].
Among these, radicals can be efficiently generated by catalytic action of metal soaps such as methyl ethyl ketone peroxide, cyclohexanone peroxide, cumene hydroperoxide, t-butyl peroxybenzoate, benzoyl peroxide, and / or amine compounds. Preferred compounds are 2,2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile).
As the photocationic polymerization initiator, the following compounds are suitable. For example, arylsulfonium salts such as triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate; diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluorophosphate, (trilccumyl) iodonium tetrakis (pentafluorophenyl) borate, etc. Aryliodonium salts; aryldiazonium salts such as phenyldiazonium tetrafluoroborate;
Of these, arylsulfonium salts and diazonium salts are preferred. In particular, (tolylcumyl) iodonium tetrakis (pentafluorophenyl) borate is preferable.
As the thermal cationic polymerization initiator, the following compounds are suitable. For example, Lewis acids (eg, boron trifluoride, titanium chloride, ferrous chloride, ferric chloride, zinc chloride, stannous chloride, stannic chloride, dibutylstannic dichloride, tetrabutyltin, Triethylaluminum, diethylaluminum chloride, etc.) and electron donating compounds (for example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, hexamethylphosphoric triamide, dimethyl sulfoxide, trimethyl phosphate, phosphoric acid Complex with triethyl, etc .; protonic acid (for example, halogenocarboxylic acids, sulfonic acids, sulfuric monoesters, phosphoric monoesters, phosphoric diesters, polyphosphoric esters, boric monoesters, boric diesters) Etc.) with a base (eg, ammonia, monoethylamine, diethylamino) , Triethylamine, pyridine, piperidine, aniline, morpholine, cyclohexylamine, monoethanolamine, diethanolamine, triethanolamine, compounds neutralized with butylamine).
Among these, amine complexes of various protonic acids are preferable because a good pot life can be secured.
As a total amount of the polymerization initiator added to the entire curable composition (C) of the present invention, the lower limit is preferably 0.05% by mass or more, and the upper limit is preferably 20% by mass or less. If it is less than 0.05% by mass, sufficient curing may not be obtained, and if it exceeds 20% by mass, no further improvement in the physical properties of the cured product is observed, and there is a possibility that it may adversely affect the economy. Sexuality may be impaired. The lower limit is more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, and the upper limit is more preferably 15% by mass or less, still more preferably 10% by mass or less.
The curable composition (C) of the present invention further comprises a polymerization inhibitor, a curing accelerator, a photosensitizer, a release agent, an antistatic agent, an antifouling agent, a refractive index adjuster, a viscosity as necessary. A regulator, binder polymer, fine particles, antioxidant, ultraviolet absorber, light stabilizer, antifoaming agent, lubricant, leveling agent, solvent, and the like can also be blended. These can be appropriately selected from conventionally known ones.
The curable composition (C) of the present invention preferably has a viscosity of 1 mPa · s or more, more preferably 3 mPa · s or more, and most preferably 5 mPa · s or more. Further, it is preferably 10,000 mPa · s or less, more preferably 5000 mPa · s or less, and most preferably 1000 mPa · s or less. When the viscosity is less than 1 mPa · s, the volatility of the curable composition may increase and bubbles may be generated during molding. On the other hand, if the viscosity is greater than 10,000 mPa · s, the curable material may not enter the unevenness of the nanometer size, and the mold shape transferability may be reduced.
It is essential that the curable composition (C) of the present invention is cured by irradiation with active energy rays and / or heating. As a method of filling the curable composition (C) between the substrate (A) and the mold (B), first, the curable composition (C) is first uniformly applied to the surface of the substrate (A). The mold (B) may be pressed, or the substrate (A) may be pressed after the curable composition (C) is uniformly applied to the surface of the mold (B). This operation is preferably performed in a reduced pressure environment in order to avoid mixing of bubbles. In addition, when an acrylic curable composition is used, it is preferably cured in a reduced pressure environment or in an inert gas atmosphere because of inhibition of curing by oxygen.
Next, when using an active energy ray as a curing method, the irradiation method may be irradiation from the direction of the substrate (A) or irradiation from the direction of the mold (B). In the case of irradiation from the direction of the substrate (A), it is necessary to use a material that transmits active energy rays as the substrate (A), and in the case of irradiation from the direction of the mold (B), the mold (B) is It is necessary to use a material that transmits active energy rays such as quartz. The light source used for irradiation is not particularly limited, such as a low pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a metal halide lamp, a gallium lamp, and a xenon lamp, but a high pressure mercury lamp, an ultra high pressure mercury lamp, and a metal halide lamp are preferable.
In the case of curing by heat, heating by infrared rays, far infrared rays, hot air, high frequency heating or the like is possible. Active energy ray irradiation and heating can be used in combination.
Irradiation energy of the active energy ray are not particularly limited as long as the amount necessary to the curing reaction proceeds sufficiently, for ^example, preferably ^{300mJ / cm 2 ~1500mJ / cm 2} , 400mJ / cm 2 ~1000mJ / cm 2 is more ^{preferably, 500mJ / cm 2 ~800mJ / cm} 2 is more preferable.
When curing by heating, the heating temperature is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and still more preferably 50 to 100 ° C. The heating time is preferably 30 seconds to 1 hour, more preferably 1 minute to 30 minutes, and still more preferably 2 minutes to 15 minutes.
The reflectance of the optical article of the present invention is preferably as low as possible. Specifically, the specular average reflectance in the wavelength region of 450 to 650 nm is preferably 2% or less, more preferably 1% or less, and further preferably 0.5% or less. preferable.
Here, the specular average reflectance in the wavelength region of 450 to 650 nm is obtained by measuring the spectral reflectance at an incident angle of 5 ° in the wavelength region of 380 to 780 nm using, for example, a spectrophotometer, and measuring 450 to 650 nm. It is possible to calculate and obtain the mirror surface average reflectance.
The structure of the present invention reduces the light reflectivity or improves the light transmittance by imparting the above structure to the surface. The “light” in this case is light including at least light having a wavelength in the visible light region.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the examples shown below.

[Glass-transition temperature]
The glass transition temperature (Tg) of each sample was determined in accordance with JIS K7121 regulations. Specifically, a differential scanning calorimeter (manufactured by Rigaku Corporation, DSC-8230) is used to raise a temperature of about 10 mg from room temperature to 200 ° C. (temperature increase rate: 20 ° C./min) in a nitrogen gas atmosphere. From the obtained DSC curve, it was evaluated by the starting point method. Α-alumina was used as a reference. In addition, evaluation of Tg with respect to the film produced by the manufacture example was performed similarly.

[Light transmittance]
The light transmittance of each sample was evaluated by measuring the transmittance of the film with respect to light having wavelengths of 380 nm and 500 nm using a spectrophotometer (manufactured by Shimadzu Corporation, UV-3100).

[Haze]
Haze was measured using a turbidimeter (NDH 5000, manufactured by Nippon Denshoku Industries Co., Ltd.).

[Weight average molecular weight]
The weight average molecular weight was determined by gel permeation chromatography (GPC) under the following conditions.
System: Tosoh developing solvent: Chloroform (made by Wako Pure Chemical Industries, special grade), flow rate 0.6 ml / min
Standard sample: TSK standard polystyrene (Tosoh, PS-oligomer kit 12 type)
Column configuration (measurement side): Guard column (TSKGuardcolumn SuperH-H), Separation column (TSKgel SuperHM-M) Series connection column configuration (reference side): Reference column (TSKgel SuperH-RC)
[Film thickness]
The thickness of the film was measured using a Digimatic Micrometer (manufactured by Mitutoyo Corporation).

[Refractive index anisotropy]
Regarding the refractive index anisotropy of the film, an in-plane retardation value (Re) and a thickness direction retardation value (Rth) were measured using a KOBRA-WR manufactured by Oji Scientific Instruments at a measurement wavelength of 589 nm. The thickness direction retardation value (Rth) was measured by tilting by 40 ° with the slow axis as the tilt axis.

[Refractive index]
Regarding the refractive index of the film, a multi-wavelength Abbe refractometer (DR-M4, manufactured by Atago Co., Ltd.) was used, and the refractive index at D line (587.6 nm) and 20 ° C. was measured. The refractive index of the curable composition was measured by preparing a plate-shaped molded product having a thickness of 1 mm. A plate-shaped molded product having a thickness of 1 mm is formed by sandwiching a spacer having a thickness of 1 mm and a curable composition between two glass plates and irradiating energy of ² J / cm ² with a high-pressure mercury lamp in a state where air is shut off. Obtained by curing.

(Base Material Production Example 1)
40 parts of methyl methacrylate (MMA), 10 parts of methyl 2- (hydroxymethyl) acrylate (MHMA), polymerization were carried out in a reaction vessel with an internal volume of 1000 L equipped with a stirrer, temperature sensor, cooling pipe and nitrogen introduction pipe. As a solvent, 50 parts of toluene and 0.025 part of an antioxidant (manufactured by Asahi Denka Kogyo Co., Ltd., Adeka Stub 2112) were charged, and the temperature was raised to 105 ° C. while introducing nitrogen. When the reflux with the temperature increase started, 0.05 part of t-amyl peroxyisononanoate (manufactured by Arkema Yoshitomi, trade name: Luperox 570) was added as a polymerization initiator, and 0.10 part of t- While amyl peroxy isononanoate was added dropwise over 3 hours, solution polymerization was allowed to proceed under reflux at about 105 to 110 ° C., followed by further aging for 4 hours.

  Next, 0.05 part of 2-ethylhexyl phosphate (manufactured by Sakai Chemical Industry Co., Ltd., Phoslex A-8) is added to the resulting polymerization solution as a catalyst for the cyclization condensation reaction (cyclization catalyst). The cyclization condensation reaction was allowed to proceed for 2 hours under reflux at 0 ° C., and then the polymerization solution was heated for 30 minutes in an autoclave at 240 ° C. to further proceed the cyclization condensation reaction to the lactone ring.

Next, the obtained polymerization solution was subjected to a barrel temperature of 240 ° C., a rotation speed of 100 rpm, a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg), a rear vent number of 1 and a forevent number of 4 (first and 2, a third and a fourth vent), a side feeder is provided between the third vent and the fourth vent, and a leaf disk type polymer filter (filtration accuracy 5 μ, filtration area 1.5 m at the tip) ² ) was introduced into a vent type screw twin screw extruder (Φ = 50.0 mm, L / D = 30) at a processing rate of 45 kg / hour in terms of resin amount, and devolatilization was performed. At that time, a separately prepared UVA solution was prepared from the rear of the first vent at a charging rate of 0.68 kg / hour with a separately prepared mixed solution of antioxidant / cyclization catalyst deactivator. Ion exchange water was charged from behind the third vent at a charging rate of 25 kg / hour from the back of the third vent at a charging rate of 0.22 kg / hour. Further, styrene-acrylonitrile (AS) resin pellets (manufactured by Asahi Kasei Chemicals Co., Ltd., Stylac AS783) were charged from the side feeder at a charging speed of 5 kg / hour.

  The antioxidant / cyclization catalyst deactivator mixed solution contains 50 parts of antioxidant (Sumitomo Chemical Sumitizer GS) and 35 parts of zinc octylate (made by Nippon Kagaku Sangyo Co., Ltd., Nikka). A solution of octix zinc (3.6%) in 200 parts of toluene was used. In the UVA solution, 37.5 parts of tinuvin 477 (manufactured by BASF, active ingredient 80%) which is an ultraviolet absorber containing a compound having a 2,4,6-tris (hydroxyphenyl) -1,3,5-triazine skeleton Was used in a solution of 12.5 parts of toluene.

  Next, after the devolatilization is completed, the resin in the hot melt state remaining in the extruder is discharged while filtering through a polymer filter from the tip of the extruder, pelletized by a pelletizer, and acrylic resin having a ring structure in the main chain. A pellet of acrylic resin (A-1) containing coalescence was obtained. The weight average molecular weight of Resin (A-1) was 145000, and Tg was 126 ° C.

The obtained resin (A-1) was introduced into a vented single screw extruder having a barrier flight type screw at a treatment rate of 30 kg / hour, and melt-kneaded while suctioning from the vent port at a pressure of 10 mmHg. Then, it is filtered through a leaf disk polymer filter with a filtration accuracy of 5 μm and a filtration area of 0.75 m ² by a gear pump, and the filtered composition is discharged from a T die (width 700 mm) onto a cooling roll at a temperature of 90 ° C. An extruded film (B-1) having a thickness of 160 μm was obtained. At this time, the temperature of the cylinder, gear pump, polymer filter, and T-die was set to 265 ° C.

  The obtained extruded film was cut out to 97 mm × 97 mm, and then longitudinally at a speed of 800 mm / min at a temperature 15 ° C. higher than the glass transition temperature using a sequential biaxial stretching machine (X-6S, manufactured by Toyo Seiki Seisakusho). -Biaxial stretching was successively performed so as to be doubled in the order of the transverse direction (MD / TD direction) to obtain a film (C-1). The film (C-1) has a thickness of 40 μm, a haze (turbidity) of 0.2%, a glass transition temperature of 126 ° C., Re of 0.7 nm, Rth of 0.8 nm, and a transmittance of 6 nm for light of 380 nm. The transmittance for 0.0% and 500 nm light was 92.1%. Further, this film had a refractive index of 1.51 at D line and 20 ° C.

(Manufacture example 2 of a base material)
An acrylic resin having a glutarimide ring structure in the main chain (Pleximide 8813 manufactured by Daicel-Evonik, glass transition temperature 132 ° C., weight average molecular weight 95000) is charged into a hopper, and a twin-screw extruder (Φ30 mm, L / L) having two vents D = 42), and melted under the conditions of a barrel temperature of 260 ° C., a rotation speed of 100 rpm, a degree of vacuum of 13 hPa, and a processing speed of 7.8 kg / hour. Next, a solution prepared by mixing 19 parts by weight of CGL777MPAD (manufactured by Ciba Specialty Chemicals Co., Ltd., 80% by weight of active ingredient) and 11 parts by weight of toluene as an ultraviolet absorber was added to the molten resin from the inlet before the vent. Acrylic resin is injected under pressure at a rate of 30 kg / hour, and styrene-acrylonitrile (AS) resin pellets (manufactured by Asahi Kasei Chemicals Co., Ltd., Stylac AS783) are charged from the side feeder at 2.2 kg / hour. A pellet of (B-1) was obtained. In this acrylic resin (B-1), the ratio of the acrylic resin having a glutarimide ring structure in the main chain, the AS resin, and the ultraviolet absorber was 78 parts by weight / 22 parts by weight / 1.5 parts by weight. The acrylic resin (B-1) had a glass transition temperature of 127 ° C. and a weight average molecular weight of 129000.

Except for using the acrylic resin (B-1), an extruded film (B-2) and a sequentially biaxially stretched film (C-2) were obtained in the same manner as in Production Example 1. The film (C-2) has a thickness of 40 μm, a haze (turbidity) of 0.5%, a glass transition temperature of 127 ° C., Re of 3.1 nm, Rth of 5.2 nm, and a transmittance of 380 nm for light of 6 nm. The transmittance for 4%, 500 nm light was 91.5%. Moreover, the refractive index in 20 degreeC of the D line | wire of this film was 1.52.

(Examples 1-4, Comparative Examples 1-3)
Urethane acrylate (UV-7600B, manufactured by Nippon Synthetic Chemical Co., Ltd.), ethoxylated bisphenol A diacrylate (SR-601, manufactured by Sartomer Japan), polyethylene glycol diacrylate (4EG-A, manufactured by Kyoeisha Chemical Co., Ltd.), phenoxyethyl Acrylate (PO-A, manufactured by Kyoeisha Chemical Co., Ltd.), 2-vinyloxyethoxyethyl acrylate (VEEA, manufactured by Nippon Shokubai Co., Ltd.), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Darocur) 1173, manufactured by BASF Japan) were mixed in the formulation shown in Table 1 and stirred for 1 hour under shading, followed by filtration with a filter having a pore diameter of 20 nm to obtain curable compositions 1 to 3. Table 1 shows the viscosity of these curable compositions and the refractive index of the cured product.

Next, the base film prepared in the production example was pasted on a glass disk having a diameter of 1 inch, and the liquid curable composition was dropped onto the base film using a dispenser. A quartz mold having a conical recess having a diameter of 200 nm, a depth of 400 nm, and a period of 220 nm arranged on the surface was pressed against the surface, and a pressure of 5 kN was applied while controlling the substrate surface uniformly. Next, after irradiating UV of energy of 500 mJ / cm ² from the mold side with a high-pressure mercury lamp (350 W, main wavelength 365 nm), the glass substrate and the substrate were released from the mold.

The surface of the optical component thus obtained is observed with an atomic force microscope (AFM), and it is confirmed that a fine uneven structure in which conical protrusions are arranged on the surface is formed in any molded body. did.
Moreover, a black tape is stuck on the back surface of the obtained optical component, and the spectral reflection of the optical component obtained with a spectrophotometer (UV-3100, manufactured by Shimadzu Corporation) at an incident angle of 5 ° and a wavelength of 400 to 780 nm. Table 2 shows the result of measuring the reflectance and calculating the specular reflectance at 450 to 650 nm.
Furthermore, the obtained optical component was placed on a flat glass plate, and the degree of warpage was visually observed. The results are also shown in Table 2.

  Since the production method of the present invention can impart a fine uneven structure to a substrate, it is suitable for various applications.

Claims (5)

A curable composition (C) is filled between a base material (A) made of a heat-resistant acrylic resin and a mold (B) having a fine concavo-convex structure on the surface, and irradiated with active energy rays and / or heated (C) A method for producing an optical member having a fine concavo-convex structure on the surface, wherein (B) is removed after curing. 2. The optical member having a fine concavo-convex structure on the surface according to claim 1, wherein the absolute value of the difference in refractive index between the cured products (A) and (C) is 0.1 or less. Method.   The method for producing an optical member having a fine concavo-convex structure on a surface according to claim 1 or 2, wherein the average period of the concavo-convex (B) in the horizontal direction is not more than the wavelength of visible light.   Said (C) is an acryl-type curable composition, The manufacturing method of the optical member which has a fine uneven structure on the surface in any one of Claims 1-3 characterized by the above-mentioned.   An optical member having a fine concavo-convex structure on the surface obtained by the method according to claim 1.