JP2012168301A - Forming method of thin metallic wire and manufacturing method of wire grid polarizer using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forming method of a thin metallic wire on an upper surface of a convex part of a substrate surface efficiently at low cost, and to provide a manufacturing method of a wire grid polarizer having high polarization performance using the forming method.SOLUTION: A forming method of a thin metallic wire for forming a thin metallic wire on a substrate surface includes a step for forming a metal microparticle layer made of metal microparticles on a bottom of a concave part of a mold having a fine concave-convex pattern on its surface, a step for forming a laminated body in which a surface of a photocurable resin layer is tightly attached along the concave-convex pattern of the mold by mounting the concave-convex pattern surface of the mold on a surface of the photocurable resin layer made of a photocurable resin composition and formed on the substrate to be pressed, a step for bonding the metal microparticle layer to the photocurable resin layer by hardening the photocurable resin layer of the laminated body with ultraviolet irradiation, and a step for removing the mold from the laminated body. Furthermore, a manufacturing method of a wire grid polarizer using the forming method is provided.

Description

  The present invention relates to a method for forming fine metal wires on a substrate such as a plastic film, and more particularly to a method for forming fine metal wires that can be used for manufacturing a wire grid polarizer or the like.

  In recent years, the progress of microfabrication technology by photolithography has been remarkable, and it has become possible to form a fine metal wire pattern with a very narrow pitch of 100 nm or less. If a pattern having such a narrow pitch, particularly a light wavelength level or lower, can be formed, it can be used not only in the semiconductor field but also in the optical field.

  In the optical field, for example, wire grid polarizers used in liquid crystal display devices, liquid crystal projectors, optical communication devices, etc., form a large number of straight metal thin wires in a grid pattern at a constant pitch parallel to each other on a transparent substrate. If the pitch of the grating is sufficiently shorter than the wavelength of the light, an excellent polarizer that can reflect the polarized component parallel to the grating and transmit the polarized component perpendicular to the grating in the incident light. It can be. The manufacture of the wire grid polarizer is usually performed by combining the above-described photolithography method, etching method, vacuum deposition method, sputtering method, and the like (see Patent Document 1). However, these methods require complicated processes and large-scale equipment, resulting in high manufacturing costs.

  On the other hand, in Patent Document 2, as a method for efficiently and reliably manufacturing a wire grid polarizer, a step of preparing a resin film in which concave portions having a lattice shape are formed, and a conductive nanomaterial is filled in the concave portions. And a method of manufacturing a wire grid polarizer including a step of removing excess conductive nanomaterial that has not been filled in the recesses. However, in the case of the manufacturing method described in Patent Document 2, the grid of fine metal wires of the obtained wire grid type polarizer is formed along the recesses on the surface of the resin film, so that a resin layer is formed between the fine metal wires. Will be. In this case, the polarization performance is improved as compared with the wire grid polarizer in which the metal layer is formed by forming the metal layer on the upper surface of the convex portion of the concavo-convex grid on the surface of the transparent substrate as disclosed in Patent Document 1. It is known to be inferior (Patent Documents 3 and 4).

JP 2010-117634 A JP 2008-139730 A Japanese Patent No. 4520445 Special Table 2003-519818

  Accordingly, an object of the present invention is to form a metal layer on the convex surface of the concavo-convex pattern on the substrate surface efficiently without using a photolithography method, a vacuum deposition method, a sputtering method, etc. The object is to provide a method of forming a fine metal wire.

  Moreover, the objective of this invention is providing the manufacturing method of a wire grid type | mold polarizer with high polarization performance using the formation method of the metal fine wire.

  The object is a method of forming a metal fine wire on the surface of a substrate, the step of forming a metal fine particle layer made of metal fine particles at the bottom of a concave portion of a mold having a fine uneven pattern on the surface, the uneven pattern of the mold The surface is placed on and pressed on the surface of the photocurable resin layer formed of the photocurable resin composition formed on the substrate, and the surface of the photocurable resin layer follows the uneven pattern of the mold. A step of forming a close-adhered laminate, a step of curing the photocurable resin layer of the laminate by ultraviolet irradiation, and adhering the metal fine particle layer to the photocurable resin layer, and from the laminate to the mold This is achieved by a method for forming a fine metal wire, including the step of removing.

  As a method for forming a fine metal wire on the substrate surface without using a photolithography method or the like, a method of using an intaglio printing method, an ink jet printing method, or the like using a metal ink containing metal fine particles is conceivable. However, it is extremely difficult to accurately print the metal ink on the upper surface of the convex portion of the concave / convex pattern formed on the substrate surface. Even if the metal ink is printed with a predetermined layer thickness without providing a concavo-convex pattern on the substrate surface, if the width or pitch of the metal fine wire is too narrow, the fine wire breaks or the adjacent fine wire contacts There is a case to do. In particular, it is difficult to form a thin line having a submicron width and pitch used in the optical field such as a wire grid polarizer.

  In the present invention, first, a metal fine particle layer made of metal fine particles is formed at the bottom of a concave portion of a mold having an uneven pattern. This is performed by filling the concave portions with metal fine particles. Next, the metal mold layer is bonded to the photocurable resin layer by pressing the mold against the photocurable resin layer formed on the substrate and curing the photocurable resin layer. Thereafter, by removing the mold, a fine inversion uneven pattern is formed on the surface of the photocurable resin layer, and the metal fine particle layer is accurately disposed on the upper surface of the convex portion formed by the photocurable resin layer. be able to. Therefore, according to the present invention, it is possible to efficiently form a metal layer on the upper surface of the convex portion of the concavo-convex pattern on the substrate surface and to form a fine metal wire on the substrate surface at low cost.

Preferred embodiments of the method for forming a fine metal wire of the present invention are as follows.
(1) The step of forming the metal fine particle layer is a step of filling a metal ink containing metal fine particles into a concave portion of a mold having a fine concavo-convex pattern on the surface, and the concave portion is not filled from the surface of the mold. A step of removing excess metal ink, and a step of drying and / or baking the metal ink filled in the concave portion of the mold. The metal ink is generally obtained by mixing and dispersing metal fine particles in a solvent or the like. Accordingly, the metal fine particles can be easily filled in the concave portions, and then the metal fine particle layer can be easily formed on the bottom of the concave portions by removing excess metal ink and drying and / or firing.
(2) The width (W) of the concave portion of the mold is 20 to 450 nm. In this invention, the width | variety of the recessed part of a metal mold | die is the width | variety of the metal fine wire to form, The method of this invention is especially effective when forming such a submicron size metal fine wire.
(3) The depth (D) of the concave portion of the mold is 1.0 to 3.0 times the width (W) of the concave portion. Thereby, since it becomes a recessed part of 2.0 ± 1.0 as an aspect ratio (D / W), a more favorable uneven | corrugated pattern and metal fine wire without damage, such as a disconnection, can be formed.
(4) The mold is made of an inorganic material selected from the group consisting of quartz, silicon and metal. Such a mold of an inorganic material can cope with a higher processing temperature when a drying / firing process is used in forming the metal fine particle layer.
(5) The temperature at which the metal ink is dried and / or baked is 100 to 400 ° C. Thereby, metal fine particles can be more integrated, and a better metal fine particle layer without damage such as disconnection can be obtained.
(6) The substrate is a transparent substrate. Thereby, since ultraviolet irradiation can be performed from the substrate side when the photocurable resin layer is cured, the photocurable resin layer can be cured more efficiently. Further, it is not necessary to use a transparent mold, and the selection range of the mold can be expanded.
(7) The layer thickness of the photocurable resin layer formed on the substrate is not less than the depth (D) of the concave portion of the mold. As a result, the photocurable resin layer can be sufficiently brought into contact with the metal fine particle layer formed at the bottom of the concave portion of the mold, and the metal fine particle layer is sufficiently formed when the photocurable resin layer is cured by ultraviolet irradiation. Can be adhered to.
(8) The photocurable resin layer is a photocurable transfer layer made of a photocurable composition containing a reactive diluent having a polymer and a photopolymerizable functional group that can be deformed by pressure. Such a photo-curable transfer layer is preferable because it is superior in handling properties than the case of using a liquid photo-curable composition.

  Moreover, the said objective is achieved by the manufacturing method of the wire grid type polarizer including the process of forming the fine metal wire of a fine lattice shape on the transparent substrate surface using the formation method of the thin metal wire of this invention.

  By using the method for forming fine metal wires according to the present invention, a metal layer is formed on the top surface of the convex portion of the concavo-convex lattice on the surface of the transparent substrate efficiently by using a method for forming a fine metal wire in a lattice shape on the substrate surface. Can do. Thereby, the wire grid type polarizer excellent in polarization performance can be manufactured at low cost. The width of the fine metal wires of the wire grid polarizer is preferably 40 to 200 nm, and more preferably 50 to 100 nm. The pitch is preferably 80 to 400 nm, more preferably 100 to 200 nm.

  In the method for forming a fine metal wire of the present invention, after forming a metal fine particle layer at the bottom of a concave portion of a mold having a fine uneven pattern, the mold is pressed against the photocurable resin layer on the substrate and cured. Since the concave / convex pattern is formed on the surface of the substrate and the metal fine particle layer is adhered to the upper surface of the convex portion of the concave / convex pattern, it is low without requiring complicated processes such as photolithography and vacuum deposition and large-scale equipment. By forming the metal layer on the upper surface of the convex portion of the concavo-convex pattern on the substrate surface efficiently and accurately at a cost, a fine metal wire can be formed on the substrate surface.

  Therefore, the method for manufacturing a wire grid polarizer including the step of forming a grid-shaped fine metal wire using the method of the present invention is a method capable of manufacturing a wire grid polarizer excellent in polarization performance at low cost. .

It is a schematic sectional drawing explaining a typical example of the method of forming the metal fine wire of this invention. It is the schematic which shows a typical example of the wire grid type | mold polarizer of this invention obtained by the method of this invention, Fig.2 (a) is a schematic plan view, FIG.2 (b) is a schematic sectional drawing. is there.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing a typical example of a method for forming a fine metal wire according to the present invention.

  The present invention is a method for forming a fine metal wire on the surface of a substrate by forming a metal layer on the upper surface of a convex portion of a fine concavo-convex pattern formed on the substrate. First, a mold 14 is prepared in which a reverse concavo-convex pattern of a fine concavo-convex pattern to be formed on a substrate is formed. Any uneven pattern may be used, and examples thereof include a lattice-shaped or mesh-shaped uneven pattern. Then, a metal fine particle layer made of metal fine particles is formed on the bottom of the recess 15 of the mold 14. The metal fine particle layer may be formed by any method such as a wet method or a dry method, as long as the metal particles can be filled in the recess 15. It is preferable to use the steps shown in FIGS. 1A to 1C in that the metal fine particles can be easily filled in the fine recesses 15.

  That is, the metal ink 20 containing metal fine particles is applied to the surface having the concave and convex pattern of the mold 14 to fill the concave portion 15 of the mold 14 with the metal ink 20 (FIG. 1A). The metal ink 20 is generally formed into an ink or paste by mixing and dispersing metal fine particles in a binder resin, a solvent, or the like, and a known ink can be appropriately selected and used. The application may be performed by any method, for example, the metal ink 20 may be dropped and applied, or the uneven pattern surface of the mold 14 may be immersed in a container in which the metal ink 20 is charged. . Next, the excess metal ink 20 that has not been filled in the concave portion 15 of the mold 14 is removed by the wiper 30 (FIG. 1B). The step of removing the metal ink 20 can use a method of wiping the surface of the concavo-convex pattern of the mold 14 by, for example, moving the wiper 30 in a direction perpendicular to the grid-like lines. As the wiper 30, a method of scraping the metal ink 20 using a thin metal plate such as a doctor blade used in gravure printing may be used.

  Thereafter, the metal ink 20 filled in the recess 15 of the mold 14 is dried and / or baked to form a metal fine particle layer 20c on the bottom of the recess 15 of the mold 14 (FIG. 1C). In the step of drying and / or firing, the solvent contained in the metal ink 20 may be evaporated by drying to form the metal fine particle layer 20c. After drying or instead of drying, firing may be performed at a higher temperature. Alternatively, the metal fine particle layer 20c may be formed by forming a sintered body of metal fine particles. In order to obtain a fine metal wire in which fine metal particles are integrated and there is no damage such as disconnection, a process including firing is preferable. The temperature for drying and / or firing is not particularly limited, but is preferably 100 to 400 ° C, more preferably 200 to 400 ° C. The time for drying and / or firing is not particularly limited, but is generally 1 minute to 10 hours, preferably 3 minutes to 1 hour.

  By using such a process, the metal fine particles can be easily filled in the recess 15, and the metal fine particle layer can be easily formed on the bottom of the recess 15.

  Next, a substrate 12 on which a fine metal wire is to be formed is prepared. A photocurable resin layer 11 made of a photocurable resin composition is formed on the surface of the substrate 12 in advance. The photocurable resin layer 11 may be a layer made of a resin composition that is cured by light irradiation. As will be described later, it may be a photocurable resin layer formed by applying a liquid photocurable resin composition, which can be deformed by pressurization and includes a reactive diluent having a polymer and a photopolymerizable functional group. A photocurable transfer layer formed of a photocurable composition may be used. A photo-curable transfer layer that can be deformed by pressurization in terms of handling properties is preferred.

And the uneven | corrugated pattern surface of the metal mold | die 14 by which the metal fine particle layer 20c was formed in the bottom part of the recessed part 15 as mentioned above on the surface of the photocurable resin layer 11 on the board | substrate 12 is used for the photocurable resin on the board | substrate 12. It is placed on the surface of the layer 11 and pressed to form a laminate in which the surface of the photocurable resin layer 11 is in close contact with the concave-convex pattern of the mold 14 (FIGS. 1D and 1E). The photocurable resin layer 11 on the substrate 12 is heated as necessary so that pressing is possible. If it can be pressed at room temperature, it is not necessary to heat. In this state, the photocurable resin layer 11 is cured by irradiation with light (ultraviolet rays (UV)). For light irradiation, many light sources that emit light in the ultraviolet to visible region can be used. For example, ultra-high pressure, high pressure, low pressure mercury lamp, chemical lamp, xenon lamp, halogen lamp, metal halide lamp, mercury lamp, carbon arc lamp, incandescent A lamp, a laser beam, etc. are mentioned. The irradiation time is not generally determined depending on the type of the lamp and the intensity of the light source, but is about 0.1 to several tens of seconds, preferably 0.5 to several seconds. The ultraviolet irradiation amount is preferably 300 mJ / cm ² or more. In order to accelerate curing, the laminate may be preheated to 30 to 80 ° C. and irradiated with ultraviolet rays.

  By curing the photocurable resin layer 11, the metal fine particle layer 20 can be bonded to the cured photocurable resin layer 11c. Thereafter, the mold 14 is removed from the cured photocurable resin layer 11c and the metal fine particle layer 20 (FIG. 2 (f)). Thereby, while forming a fine inversion uneven | corrugated pattern in the surface of the photocurable resin layer 11c, the metal fine particle layer 20c can be accurately arrange | positioned on the convex part upper surface formed of the photocurable resin layer 11c.

  With such a method for forming a fine metal wire, it is possible to form a fine metal wire on the substrate surface at a lower cost than a method in which a complicated process or a photolithography method requiring a large facility is combined. In addition, even for sub-micron narrow metal wires with narrow widths and pitches such as those used in the optical field such as wire grid polarizers, metal is used on the substrate by intaglio printing or ink jet printing. Compared with the method of directly forming the fine line, the metal layer can be accurately formed on the upper surface of the convex part of the concavo-convex pattern on the substrate surface, and the fine metal line can be formed on the substrate surface.

  Below, each material used for the formation method of the metal fine wire of this invention is demonstrated in detail.

[Mold]
In the present invention, the mold 14 may be any one as long as a fine uneven pattern is formed. Examples of the uneven pattern include a lattice shape and a mesh shape. In the present invention, the width of the concave portion 15 of the concave / convex pattern of the mold 14 is the width of the fine metal wire formed on the substrate 12. Since the present invention is particularly effective when forming a thin metal wire having a narrow width or pitch of submicron size as used in the optical field such as a wire grid polarizer, the width (W) of the concave portion of the mold is 20 to 450 nm is preferable, and 50 to 200 nm is more preferable.

  In addition, if the ratio of the height to the width of the fine metal wire formed on the substrate 12 (height / width) is too large, the fine metal wire such as disconnection or contact with the adjacent fine wire may be damaged. The aspect ratio (D / W) of the depth (D) of the concave portion 15 (corresponding to the height of the fine metal wire) to the width (W) of the concave portion 15 of 14 (corresponding to the width of the fine metal wire) is 2.0 ± 1. 0.0, preferably 2.0 ± 0.5. Therefore, the depth (D) of the recess 15 is preferably 1.0 to 3.0 times the width (W) of the recess 15, and more preferably 1.5 to 2.5 times.

  The material of the mold 14 is not particularly limited, and may be made of metal or resin. In particular, when a metal ink is used when forming the metal fine particle layer on the bottom of the recess 15 of the mold 14, the metal ink can be dried and / or baked at a higher temperature condition. Inorganic materials selected from the group consisting of quartz, silicon, and metals such as nickel and titanium are preferred.

[Metal fine particles]
The metal fine particles for forming the metal fine particle layer in the present invention may be any material, for example, metals such as silver, gold, copper, platinum, aluminum, tungsten, zinc, palladium, tin oxide, indium oxide, tin doped Examples thereof include metal oxides such as indium oxide (ITO) and zinc oxide, carbon materials such as graphite, and organometallic compounds such as organometallic complexes. The particle diameter of the metal fine particles may be smaller than the width of the fine metal wire formed according to the present invention, preferably 30 nm or less, and more preferably 1 to 20 nm. The layer thickness of the metal fine particle layer is not particularly limited as long as it is less than the depth (D) of the recess 15 of the mold 14. Generally, it is 0.1 to 0.9 times the depth (D), preferably 0.2 to 0.8 times, and more preferably 0.3 to 0.7 times.

  In the present invention, it is preferable to use a metal ink containing metal fine particles in order to form the metal fine particle layer.

  The metal ink is, for example, a composition in which the above metal fine particles are mixed and dispersed in a dispersion medium such as water or an organic solvent together with additives such as a binder resin, a dispersion stabilizer, and a surfactant to form an ink or paste. Can be used. These can be used by appropriately selecting known ones, and for example, commercially available silver nanometal ink, gold nanometal ink, copper nanometal ink, ITO nanometal ink (above, ULVAC Material Co., Ltd.) and the like can be used.

[substrate]
In the present invention, the material of the substrate 12 on which the fine metal wires are formed is not particularly limited, and any material can be used depending on the application. However, in the case of an opaque substrate, when the photocurable resin layer is cured, ultraviolet irradiation is performed from the mold side, and there is a restriction that it is necessary to use a transparent mold. In addition, when the ultraviolet irradiation is performed from the mold side, the metal fine particle layer may shield the ultraviolet ray, so that the portion of the photocurable resin is difficult to be cured. Therefore, the substrate is preferably a transparent substrate in that it can be irradiated with ultraviolet rays from the substrate side and the photocurable resin layer can be cured more efficiently. Examples of the transparent substrate include a transparent resin substrate such as a transparent plastic film, and a glass plate. The transparent plastic film is preferably a polyester film. This polyester is a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof.

  Examples of such polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalate, polyethylene isophthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), and the like. be able to.

  The thickness of the substrate 12 is not particularly limited, and is generally 1 μm to 1 mm, preferably 1 to 500 μm, and more preferably 3 to 400 μm.

[Photocurable resin layer]
In the present invention, the photocurable resin layer 11 is a layer made of a fat composition that is cured by light irradiation, and has good adhesion to the substrate 12 and the metal fine particle layer 20c and releasability from the mold 14. Any layer is acceptable.

  The thickness of the photocurable resin layer is not particularly limited, but is sufficiently brought into contact with the metal fine particle layer 20c and sufficiently adheres to the metal fine particle layer 20c when the photocurable resin layer is cured by ultraviolet irradiation. It is preferable to have a thickness equal to or greater than the depth (D) of the recess 15 of the mold 14 so as to be able to. 1-300 micrometers is preferable and, as for the thickness of the photocurable resin layer 11, 3-100 micrometers is more preferable.

  The photocurable resin layer 11 may be, for example, a photocurable transfer layer made of a photocurable composition that can be deformed by pressure and includes a reactive diluent having a polymer and a photopolymerizable functional group, It may be formed by applying a liquid photocurable resin composition to the substrate surface.

  In the case of said photocurable transfer layer, it can be set as the photocurable transfer sheet which formed the photocurable transfer layer on the transparent plastic film which is a board | substrate. On the other hand, in the case of a liquid photocurable resin composition, each time the method of the present invention is performed, the photocurable resin composition is applied to form a photocurable resin layer. Therefore, the above-mentioned photocurable transfer layer is preferable because the photocurable resin layer 11 is excellent in handling properties.

[Photocurable transfer layer]
In the present invention, the photocurable composition for forming the photocurable transfer layer comprises a polymer, a photopolymerizable functional group (generally a carbon-carbon double bond group, preferably a (meth) acryloyl group (acryloyl group and methacryloyl group). The same applies hereinafter))), and further comprises, if desired, a photopolymerizable initiator and other additives.

[polymer]
Examples of the polymer constituting the photocurable composition include acrylic resin, polyvinyl acetate, vinyl acetate / (meth) acrylate copolymer, ethylene / vinyl acetate copolymer, polystyrene and its copolymer, polyvinyl chloride and its Copolymer, butadiene / acrylonitrile copolymer, acrylonitrile / butadiene / styrene copolymer, methacrylate / acrylonitrile / butadiene / styrene copolymer, 2-chlorobutadiene-1,3-polymer, chlorinated rubber, styrene / butadiene / Examples thereof include styrene copolymers, styrene / isoprene / styrene block copolymers, epoxy resins, polyamides, polyesters, polyurethanes, cellulose esters, cellulose ethers, polycarbonates, and polyvinyl acetals.

  The polymer in the present invention is preferably an acrylic resin from the viewpoint of good transferability and excellent curability. As described above, the acrylic resin is particularly preferably an acrylic resin having a polymerizable functional group or an acrylic resin having a hydroxyl group. In addition, when the acrylic resin contains at least 50% by mass (especially 60 to 90% by mass) of methyl methacrylate repeating units, it is easy to obtain an acrylic resin having a Tg of 80 ° C. or more, and good transferability and high-speed curability are also obtained. It is easy and preferable.

  Moreover, it is preferable that the polymer which comprises a photocurable composition is a polymer whose glass transition temperature (Tg) is 80 degreeC or more. Thereby, the fine uneven | corrugated pattern of a metal mold | die can be transcribe | transferred easily, and hardening can also be performed at high speed. Further, since the cured shape also has a high Tg, the shape can be maintained for a long time without changing. A polymer having a glass transition temperature of 80 ° C. or higher has a polymerizable functional group, which can react with a reactive diluent and is advantageous in increasing the speed of curing. In addition, by including a diisocyanate in the transfer layer by having a hydroxyl group, it is possible to slightly crosslink the polymer, which is particularly advantageous for forming a layer in which the transfer layer exudes and the layer thickness fluctuation is greatly suppressed. It is. Diisocyanates are effective to some extent even in polymers without hydroxyl groups.

In the present invention, when an acrylic resin is used as the polymer, an acrylic resin having a polymerizable functional group or an acrylic resin having a hydroxyl group is particularly preferable.
In the present invention, the acrylic resin having a polymerizable functional group is a copolymer having glycidyl (meth) acrylate as a monomer component, and the glycidyl group reacts with a carboxylic acid having a polymerizable functional group, or is polymerizable. It is a copolymer having a carboxylic acid having a functional group as a monomer component, and glycidyl (meth) acrylate is reacted with the carboxylic acid group.

[Reactive diluent]
In this invention, the following are mentioned as a reactive diluent (monomer and oligomer) which has a photopolymerizable functional group contained in a photocurable transfer composition. For example, (meth) acrylate monomers include 1,6-hexanediol di (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethylhexyl polyethoxy (meth) acrylate, benzyl (meth) acrylate, phenyloxyethyl (meth) acrylate, tetrahydrofurfuryl ( (Meth) acrylate, acryloylmorpholine, N-vinylcaprolactam, o-phenylphenyloxyethyl (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, neope Cyl glycol di (meth) acrylate, neopentyl glycol dipropoxy di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, nonanediol di (meth) acrylate, glycerin diacrylate, glycerin acrylate methacrylate, glycerin dimethacrylate , Trimethylolpropane diacrylate, trimethylolpropane acrylate methacrylate, trimethylolpropane dimethacrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, tris [(meth) acrylic Roxyethyl] isocyanurate, ditrimethylolpropane tetra (meth) acrylate , Mention may be made of dimethylol tricyclodecane (meth) acrylate, isobornyl (meth) acrylate, tricyclodecane mono (meth) acrylate, dicyclopentenyl oxyethyl (meth) acrylate, and the like. (Meth) acrylate oligomers include polyol compounds (for example, ethylene glycol, propylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol). , 2-ethyl-2-butyl-1,3-propanediol, trimethylolpropane, diethylene glycol, dipropylene glycol, polypropylene glycol, 1,4-dimethylolcyclohexane, bisphenol A polyethoxydiol, polytetramethylene glycol and other polyols A polyol which is a reaction product of the polyol and a polybasic acid such as succinic acid, maleic acid, itaconic acid, adipic acid, hydrogenated dimer acid, phthalic acid, isophthalic acid, terephthalic acid, or an acid anhydride thereof. Terpolyols, polycaprolactone polyols which are a reaction product of the polyols and ε-caprolactone, a reaction product of the polyols and the ε-caprolactone of a polybasic acid or an acid anhydride thereof, a polycarbonate polyol, Polymer polyols) and organic polyisocyanates (for example, tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane-4,4′-diisocyanate, dicyclopentanyl diisocyanate, hexamethylene diisocyanate, 2,4,4′-trimethyl) Hexamethylene diisocyanate, 2,2 ′, 4-trimethylhexamethylene diisocyanate and the like) and a hydroxyl group-containing (meth) acrylate (for example, 2-hydroxyethyl (meth) acrylate, 2 Hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, cyclohexane-1,4-dimethylol mono (meth) acrylate, pentaerythritol tri (meth) A reaction product of polyurethane (meth) acrylate, bisphenol A type epoxy resin, bisphenol F type epoxy resin, etc., which is a reaction product of acrylate, glycerin di (meth) acrylate, etc., and bisphenol, which is a reaction product of (meth) acrylic acid Type epoxy (meth) acrylate and the like. These compounds having a photopolymerizable functional group can be used alone or in combination of two or more.

  In the present invention, the mass ratio of the polymer of the photocurable composition to the reactive diluent is preferably in the range of 20:80 to 80:20, particularly 30:70 to 70:30.

[Photopolymerization initiator]
As the photopolymerization initiator contained in the photocurable composition forming the photocurable transfer layer, any known photopolymerization initiator can be used, but it has good storage stability after blending. Is desirable. Examples of such photopolymerization initiators include benzoin series such as acetophenone series and benzyldimethyl ketal, thiophenone series such as benzophenone series, isopropylthioxanthone, and 2-4-diethylthioxanthone, and other special types include methylphenylglycol. Oxylate can be used. Particularly preferably, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1, Examples include benzophenone. These photopolymerization initiators may contain one or two or more kinds of known and commonly used photopolymerization accelerators such as benzoic acid-based or tertiary amine-based compounds such as 4-dimethylaminobenzoic acid as required. Can be mixed and used. Moreover, it can be used by 1 type, or 2 or more types of mixture of only a photoinitiator. In general, the photocurable composition (nonvolatile content) preferably contains 0.1 to 20% by mass, particularly 1 to 10% by mass of a photopolymerization initiator.

  Among the photopolymerization initiators, examples of the acetophenone-based polymerization initiator include 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 4-t-butyl-trichloroacetophenone, diethoxyacetophenone, and 2-hydroxy-2. -Methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methyl Propan-1-one, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2 As benzophenone polymerization initiators such as morpholinopropane-1, Benzophenone, benzoyl benzoate, methyl benzoyl benzoate, 4-phenyl benzophenone, hydroxybenzophenone, 4-Benzzoiru 4'-methyl diphenyl sulfide, etc. 3,3'-dimethyl-4-methoxybenzophenone may be used.

  As the acetophenone-based polymerization initiator, in particular, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2 -Morpholinopropane-1 is preferred. As the benzophenone polymerization initiator, benzophenone, benzoylbenzoic acid, and methyl benzoylbenzoate are preferable. Tertiary amine photopolymerization accelerators include triethanolamine, methyldiethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone, 4,4'-diethylaminobenzophenone, ethyl 2-dimethylaminobenzoate. , Ethyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate (n-butoxy), isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate and the like can be used. Particularly preferably, as the photopolymerization accelerator, ethyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate (n-butoxy), isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, etc. Is mentioned.

[Diisocyanate]
In the present invention, when diisocyanate is added as a curing agent to the photocurable composition forming the photocurable transfer layer, tolylene diisocyanate (TDI), isophorone diisocyanate, xylylene diisocyanate, diphenylmethane-4,4-diisocyanate. Dicyclopentanyl diisocyanate, hexamethylene diisocyanate, 2,4,4′-trimethylhexamethylene diisocyanate, 2,2 ′, 4-trimethylhexamethylene diisocyanate can be used. Polyisocyanate cyanates such as trifunctional or higher functional isocyanate compounds such as a TDI adduct of trimethylolpropane can also be used. Of these, a hexamethylene diisocyanate adduct of trimethylolpropane is preferred.

  In the present invention, the diisocyanate is preferably contained in the photocurable composition (nonvolatile content) in the range of 0.2 to 4% by mass, particularly 0.2 to 2% by mass. Appropriate crosslinking is provided to prevent the transfer layer from seeping out, and good transferability of the unevenness of a mold such as a stamper is also maintained. The reaction between the compound and the polymer proceeds gradually after the transfer layer is formed, and reacts considerably at room temperature (generally 25 ° C.) at 24 hours. It is considered that the reaction proceeds after the coating solution for forming the transfer layer is prepared and before the coating solution is applied. After forming the transfer layer, it is preferable to cure to a certain extent before winding it in the roll state. If necessary, the reaction is promoted by heating during the formation of the transfer layer or before winding in the roll state. You may let them.

[Others]
In the present invention, it is preferable to add the following thermoplastic resin and other additives to the photocurable composition for forming the photocurable transfer layer, if desired.

  As another additive, a lubricant (release agent) can be added in order to further improve the releasability. Examples of the lubricant include phosphoric acid-containing polyalkylene compounds, phosphoric acid trialkyl ester compounds, phosphorus atom-containing compounds such as phosphates and phosphoric acid amides, and silicone resins such as non-modified or modified polysiloxanes. The addition amount of the lubricant is usually 0.01 to 5 parts by mass with respect to 100 parts by mass of the polymer (solid content).

  Moreover, a silane coupling agent (adhesion promoter) can be added as another additive. As this silane coupling agent, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxy Propyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β There are (aminoethyl) -γ-aminopropyltrimethoxysilane and the like, and one of these can be used alone or two or more of them can be used in combination. As for the addition amount of these silane coupling agents, 0.01-5 mass parts is sufficient normally with respect to 100 mass parts of said polymers (solid content).

  Similarly, an epoxy group-containing compound can be added for the purpose of improving adhesiveness. Examples of the epoxy group-containing compound include triglycidyl tris (2-hydroxyethyl) isocyanurate; neopentyl glycol diglycidyl ether; 1,6-hexanediol diglycidyl ether; acrylic glycidyl ether; 2-ethylhexyl glycidyl ether; Examples thereof include phenol glycidyl ether; pt-butylphenyl glycidyl ether; adipic acid diglycidyl ester; o-phthalic acid diglycidyl ester; glycidyl methacrylate; Further, the same effect can be obtained by adding an oligomer containing an epoxy group having a molecular weight of several hundred to several thousand or a polymer having a weight average molecular weight of several thousand to several hundred thousand. The addition amount of these epoxy group-containing compounds is sufficient to be 0.1 to 20 parts by mass with respect to 100 parts by mass of the polymer (solid content), and at least one of the epoxy group-containing compounds is added alone or in combination. Can do.

  Furthermore, as another additive, a hydrocarbon resin can be added for the purpose of improving workability such as workability and bonding. In this case, the added hydrocarbon resin may be either a natural resin type or a synthetic resin type. In natural resin systems, rosin, rosin derivatives, and terpene resins are preferably used. For rosin, gum-based resins, tall oil-based resins, and wood-based resins can be used. As the rosin derivative, rosin obtained by hydrogenation, heterogeneity, polymerization, esterification, or metal chloride can be used. As the terpene resin, a terpene phenol resin can be used in addition to a terpene resin such as α-pinene and β-pinene. In addition, dammar, corbal and shellac may be used as other natural resins. On the other hand, in the synthetic resin system, petroleum resin, phenol resin, and xylene resin are preferably used. As the petroleum resin, aliphatic petroleum resin, aromatic petroleum resin, alicyclic petroleum resin, copolymer petroleum resin, hydrogenated petroleum resin, pure monomer petroleum resin, and coumarone indene resin can be used. As the phenol resin, an alkyl phenol resin or a modified phenol resin can be used. As the xylene-based resin, a xylene resin or a modified xylene resin can be used.

  Although the addition amount of resin, such as the said hydrocarbon resin, is selected suitably, 1-20 mass parts is preferable with respect to 100 mass parts of said polymers (solid content), More preferably, it is 5-15 mass parts.

  In addition to the above additives, the photocurable composition of the present invention may contain a small amount of an ultraviolet absorber, an antioxidant, a dye, a processing aid and the like. In some cases, additives such as fine particles such as silica gel and calcium carbonate may be contained in a small amount.

In the present invention, the storage elastic modulus at a frequency of 1 Hz of the photocurable transfer layer is preferably 1 × 10 ⁷ Pa or less at 25 ° C., and particularly in the range of 1 × 10 ^{4 to} 6 × 10 ⁵ Pa. preferable. Moreover, it is preferable that it is 8 * 10 < ⁴ > Pa or less in 80 degreeC, and it is especially preferable that it is the range of 1 * 10 < ⁴ > -5 * 10 < ⁵ > Pa. This enables accurate and quick transfer. Furthermore, the photocurable transfer layer of the present invention preferably has a glass transition temperature of 20 ° C. or lower. Thereby, when the obtained photocurable transfer layer is pressure-bonded to the uneven surface of a mold such as a stamper, it can have flexibility to closely follow the uneven surface even at room temperature. In particular, when the glass transition temperature is in the range of 15 ° C. to −50 ° C., and further in the range of 0 ° C. to −40 ° C., the followability is high. If the glass transition temperature is too high, a high pressure and a high pressure are required at the time of bonding, leading to a decrease in workability. If it is too low, sufficient hardness after curing cannot be obtained.

Moreover, in this invention, it is preferable that the photocurable transfer layer is designed so that the glass transition temperature after 300mJ / cm < ² > ultraviolet irradiation may be 65 degreeC or more. By irradiating with ultraviolet rays for a short time, it is easy to prevent the occurrence of sagging such as a shape that is likely to occur due to residual stress during transfer, and the transferred shape or the like can be retained.

  Any method may be used to form a photocurable transfer layer on the surface of the substrate 12 as the photocurable resin layer 11. The constituents of the above-mentioned photocuring composition are uniformly mixed, kneaded with an extruder, roll, etc., then formed into a film by a film forming method such as calendering, roll, T-die extrusion, inflation, etc. and wound around the cylindrical member 12 The method or each constituent component is uniformly mixed and dissolved in a good solvent, and applied to the cylindrical member 12 by a flow coating method, a roll coating method, a gravure roll method, a Myer bar method, a lip die coating method, etc., and the solvent is dried. Examples include a method for forming a film.

  In view of handling properties, a release sheet may be provided on the photocurable transfer layer and stored, and the release sheet may be removed and used at the time of use.

[Liquid photocurable resin composition]
In this invention, when using a liquid photocurable resin composition for the photocurable resin layer 12, the composition which can be especially used for a nanoimprint process method is preferable. The viscosity of the liquid composition is preferably 10 to 10,000 cps. The photocurable resin composition is preferably a composition containing a photocurable resin and a photoinitiator.

  Examples of the photocurable resin include urethane acrylate, polyester acrylate, epoxy acrylate, epoxy resin, imide-based oligomer, polyene / thiol-based oligomer, and the like.

  As the photopolymerization initiator, for example, the above-mentioned photopolymerization initiator is preferably used. Generally the addition amount of a photoinitiator is 0.1-15 weight part with respect to 100 weight part of photocurable resins, Preferably, it is 0.5-10 weight part.

  The above-mentioned reactive diluent may be added to the photocurable resin composition, and further, if necessary, generally added photopolymerization initiation assistant, thermal polymerization inhibitor, filler, adhesion An imparting agent, a thixotropic agent, a plasticizer, a colorant, and the like may be added.

[Manufacturing method of wire grid polarizer]
In this invention, the wire grid type polarizer excellent in polarization performance can be manufactured at low cost by using the manufacturing method of the metal fine wire of this invention.

  That is, the manufacturing method of the wire grid type polarizer of the present invention is a manufacturing method including a step of forming fine grid-shaped metal wires on the surface of the transparent substrate using the method of forming metal wires of the present invention.

  Specifically, for example, using a mold made of silicon having a fine uneven pattern in a lattice shape as the mold 14 and a transparent substrate such as a transparent plastic film as the substrate 12, FIGS. A thin metal wire is formed by the method described in (1). As the transparent substrate, a photocurable transfer sheet product in which a photocurable transfer layer is formed as a photocurable resin layer 11 on a transparent plastic film can also be used. There is no restriction | limiting in particular as a metal microparticle which forms a metal microparticle layer, For example, a silver microparticle, a copper microparticle, etc. can be used.

  Thereby, the wire grid type | mold polarizer excellent in the polarization performance in which the metal thin line was formed by forming a metal layer on the convex part upper surface of the uneven | corrugated grating | lattice of the transparent substrate surface can be manufactured at low cost.

  FIG. 2 is a schematic view showing a typical example of a wire grid polarizer obtained by the production method of the present invention, FIG. 2 (a) is a schematic plan view, and FIG. 2 (b) is a schematic cross-sectional view. FIG. In the wire grid polarizer obtained by the production method of the present invention, a concavo-convex lattice is formed by the photocurable resin layer 41 formed on the surface of the transparent plastic substrate 42, and the metal fine particle layer 45 is formed on the upper surface of the convex portion. As a result, a fine grid-shaped metal fine wire is formed on the surface of the transparent plastic substrate 42. Such a wire grid type polarizer is excellent in polarization performance. The width (W) of the fine metal wire is preferably 40 to 200 nm, and more preferably 50 to 100 nm. The pitch (P) (lattice period) is preferably 80 to 400 nm, and more preferably 100 to 200 nm.

  Hereinafter, the present invention will be described by way of examples.

A silver nanometal ink (silver fine particles; average) is used as a metal ink on the concavo-convex surface of a silicon mold (mold) (manufactured by NIL Technology) having a concavo-convex lattice with a recess width of 50 nm, a depth of 100 nm, and a protrusion width of 50 nm. A particle size of about 3 nm) (manufactured by ULVAC Material Co., Ltd.) was applied dropwise (see FIG. 1A). Next, the silver nanometal ink not filled in the recesses was removed by wiping in a direction perpendicular to the concavo-convex line using a wiper (see FIG. 1B). The mold was treated at 100 ° C. for 3 minutes, the ink was dried to evaporate the solvent, and then the mold was treated at 220 ° C. for 20 minutes to fire the silver nanometal ink. As a result, a silver fine particle layer was formed on the bottom of the concave portion of the concave and convex lattice of the mold (FIG. 1C). Next, light in which an acrylic resin photocurable transfer layer (thickness 25 μm) is formed on a PET film (thickness 50 μm) (trade name HPE, manufactured by Teijin DuPont Films) as a substrate and a photocurable resin layer Using a curable transfer sheet, this was placed on and pressed against the concave / convex lattice surface of the mold having the silver fine particle layer formed on the bottom of the concave portion to form a laminate (see FIGS. 1D and 1E). The laminate was irradiated with ultraviolet rays from the PET film side (metal halide lamp, 1000 mJ / cm ² (200 mW / cm ² )) to cure the photocurable transfer layer. Then, the mold was removed from the photocurable transfer sheet to obtain a PET film on which fine metal wires were formed.

  When the obtained fine metal wire was observed with an electron microscope (SEM), a concavo-convex lattice was formed on the PET film, and a silver fine particle layer was favorably formed on the upper surface of the convex portion.

  In addition, this invention is not limited to the structure and Example of said embodiment, A various deformation | transformation is possible within the range of the summary of invention.

  According to the method for forming a fine metal wire of the present invention, the fine metal wire can be formed at a low cost when manufacturing each electronic component and optical component. In particular, a wire grid polarizer excellent in polarization performance used in a liquid crystal display device, a liquid crystal projector, an optical communication device, etc. can be obtained at low cost.

11 Photocurable resin layer 11c Photocurable resin layer (after curing)
DESCRIPTION OF SYMBOLS 12 Substrate 14 Mold 15 Recess 20 Metal ink 20c Metal fine particle layer 30 Wiper 40 Wire grid type polarizer 41 Photocurable resin layer 42 Transparent plastic substrate 45 Metal fine particle layer

Claims (10)

A method of forming fine metal wires on a substrate surface,
Forming a metal fine particle layer composed of metal fine particles at the bottom of a concave portion of a mold having a fine uneven pattern on the surface;
The concave / convex pattern surface of the mold is placed on and pressed against the surface of a photocurable resin layer made of a photocurable resin composition formed on a substrate, and the surface of the photocurable resin layer is Forming a laminated body in close contact with the uneven pattern of the mold,
A step of curing the photocurable resin layer of the laminate by ultraviolet irradiation, adhering the metal fine particle layer to the photocurable resin layer, and removing the mold from the laminate. Forming method. Forming the metal fine particle layer comprises:
Filling a metal ink containing fine metal particles into a concave portion of a mold having a fine uneven pattern on the surface;
The method according to claim 1, further comprising: removing from the surface of the mold excess metal ink that has not been filled in the concave portion; and drying and / or baking the metal ink filled in the concave portion of the mold. A method for forming a metal fine wire as described.   The method for forming a fine metal wire according to claim 1 or 2, wherein the recess has a width (W) of 20 to 450 nm.   The method for forming a fine metal wire according to any one of claims 1 to 3, wherein the depth (D) of the concave portion of the mold is 1.0 to 3.0 times the width (W) of the concave portion.   The method for forming a fine metal wire according to any one of claims 1 to 4, wherein the mold is made of an inorganic material selected from the group consisting of quartz, silicon, and metal.   The method for forming a fine metal wire according to any one of claims 2 to 5, wherein a temperature at which the metal ink is dried and / or baked is 100 to 400 ° C.   The said board | substrate is a transparent substrate, The formation method of the metal fine wire of any one of Claims 1-6.   The method for forming a fine metal wire according to any one of claims 1 to 7, wherein a layer thickness of the photocurable resin layer formed on the substrate is equal to or greater than a depth (D) of the concave portion of the mold.   The photocurable resin layer is a photocurable transfer layer comprising a photocurable composition containing a reactive diluent having a polymer and a photopolymerizable functional group, which is deformable by pressurization. The method for forming a thin metal wire according to any one of the above items.   The manufacturing method of the wire grid type polarizer including the process of forming the fine metal wire of a fine lattice shape in the transparent substrate surface using the formation method of the thin metal wire of any one of Claims 1-9.

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