JP2007237541A - Mold having minute uneven shape on surface, method for producing the mold, and method for producing glare-proof film by using the mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold which is useful for manufacturing a glare-proof film indicating a high glare-proof function and has a minute uneven shape on the surface and a method for producing the mold and to produce the glare-proof film which enough prevents the lowering of visibility by whitening while indicating the high glare-proof function, and prevents the occurrence of glaringness when arranged in a high precision image display. <P>SOLUTION: Copper plating or nickel plating is applied on the surface of a substrate 41, the plated surface is polished, and unevenness 43 is formed on the polished surface 42 by dashing fine particles. After the uneven shape is worked to be made blunt, a chromium plated layer 46 is formed on the uneven surface to make the mold. The Vickers hardness of the mold surface is at least 800. The arithmetic mean height Pa in an optional cross-sectional curve of the uneven surface is 0.01-0.5 μm, and the ratio Pa/PSm between the arithmetic mean height Pa and the mean length PSm in the cross-sectional curve is 0.001-0.012. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention produces a mold having a fine irregular shape on the surface, a method for producing the mold, and an anti-glare film having excellent anti-glare properties while having low haze. It is about the method.

  In an image display device such as a liquid crystal display, a plasma display panel, a cathode ray tube (CRT) display, and an organic electroluminescence (EL) display, visibility is significantly impaired when external light is reflected on the display surface. In order to prevent such reflection of external light, TVs and personal computers that emphasize image quality, video cameras and digital cameras used outdoors with strong external light, mobile phones that display using reflected light, etc. In the conventional art, a film layer for preventing the reflection of external light has been provided on the surface of the image display device. This film layer consists of a film that has been subjected to anti-reflection treatment using interference by the optical multilayer film, and anti-glare treatment that scatters incident light by blurring the incident light by forming fine irregularities on the surface. It is divided roughly into the thing which consists of the film which was given. Among these, the former non-reflective film needs to form a multilayer film having a uniform optical film thickness, and thus increases the cost. On the other hand, since the latter anti-glare film can be produced at a relatively low cost, it is widely used in applications such as large personal computers and monitors.

  Conventionally, such an antiglare film has, for example, a resin solution in which a filler is dispersed is applied on a base sheet, and the coating film thickness is adjusted to expose the filler on the surface of the coating film, thereby causing random unevenness on the sheet. It is manufactured by the method of forming on top. However, the antiglare film produced by dispersing such a filler has an unevenness as intended because the arrangement and shape of the unevenness depends on the dispersion state and application state of the filler in the resin solution. There is a problem that it is difficult to obtain, and sufficient anti-glare performance cannot be obtained if the haze is low. Furthermore, when such a conventional anti-glare film is disposed on the surface of an image display device, there is a problem that the entire display surface becomes whitish due to scattered light, and the display becomes cloudy, so-called whitening is likely to occur. It was. In addition, with recent high-definition image display devices, the pixels of the image display device and the surface irregularity shape of the antiglare film interfere with each other, and as a result, a so-called glare phenomenon that the luminance distribution is generated and is difficult to see easily occurs. There was also a problem.

  On the other hand, there is also an attempt to develop anti-glare properties only by fine irregularities formed on the surface of the transparent resin layer without containing a filler. For example, Japanese Patent Application Laid-Open No. 2002-189106 (Patent Document 1) discloses that the ionizing radiation curable resin is cured in a state where the ionizing radiation curable resin is sandwiched between an embossing mold and a transparent resin film. An ionizing radiation curable resin in which fine irregularities are formed in which the average distance between adjacent convex portions on the original 10-point average roughness and the three-dimensional roughness reference surface satisfies predetermined values, respectively, and the irregularities are formed. An antiglare film having a layer provided on the transparent resin film is disclosed.

  In addition, it is also possible to use a film having fine irregularities formed on the surface as a light diffusion layer disposed on the back side of the liquid crystal display device, instead of an antiglare film disposed on the display surface of the display device. It is disclosed in Japanese Laid-Open Patent Publication No. 6-34961 (Patent Document 2), Japanese Unexamined Patent Application Publication No. 2004-45471 (Patent Document 3), Japanese Unexamined Patent Application Publication No. 2004-45472 (Patent Document 4), and the like.

  As a method for forming irregularities on the surface of the film, in Patent Document 3 and Patent Document 4 described above, an embossing roll having a shape obtained by inverting the irregularities is filled with an ionizing radiation curable resin liquid, and the filled resin is subjected to roll intaglio. The transparent base material that runs in synchronization with the rotation direction of the roller is brought into contact, and when the transparent base material is in contact with the roll intaglio, the resin between the roll intaglio and the transparent base material is cured and cured simultaneously with the curing. A method is disclosed in which after the resin and the transparent substrate are brought into close contact with each other, the laminate of the cured resin and the transparent substrate is peeled off from the roll intaglio.

  In such a method, the composition of the ionizing radiation curable resin liquid that can be used is limited, and leveling as when applied by diluting with a solvent cannot be expected, so there is a problem in film thickness uniformity. It is expected that. Furthermore, since it is necessary to directly fill the embossing roll intaglio with the resin liquid, in order to ensure the uniformity of the uneven surface, the embossing roll intaglio requires high mechanical accuracy, and it is difficult to produce the embossing roll. there were.

  Next, as a method for producing a roll used for producing a film having irregularities on the surface, for example, in Patent Document 2, a cylindrical body is made using a metal or the like, and electronic engraving, etching, sandblasting, or the like is formed on the surface. A method of forming irregularities by the above method is disclosed. Japanese Patent Laid-Open No. 2004-29240 (Patent Document 5) discloses a method for producing an emboss roll by a bead shot method, and Japanese Patent Laid-Open No. 2004-90187 (Patent Document 6) discloses an emboss roll. Forming a metal plating layer on the surface of the metal, mirror polishing the surface of the metal plating layer, blasting the mirror-plated metal plating layer with ceramic beads, and peening if necessary A method for producing an embossing roll through the steps is disclosed.

  Thus, in the state where the surface of the embossing roll has been subjected to blasting, the uneven diameter distribution resulting from the particle size distribution of the blast particles occurs, and it is difficult to control the depth of the indentation obtained by blasting. In addition, there is a problem in obtaining an uneven shape having an excellent antiglare function with good reproducibility.

  Further, Patent Document 1 describes that a concavo-convex surface is formed by a sandblasting method or a bead shot method, preferably using a chrome-plated roller on the surface of iron. Furthermore, it is preferable to use the mold surface with the unevenness after applying chrome plating for the purpose of improving durability during use, thereby achieving hardening and corrosion prevention. There is also a statement that it is possible. On the other hand, in each of the examples of Patent Document 3 and Patent Document 4, chrome plating is performed on the surface of the iron core, liquid sand blasting treatment of # 250 is performed, and then chrome plating treatment is performed again to form a fine uneven shape on the surface. It is described to do.

  In such an embossing roll manufacturing method, since blasting or shot is performed on chromium plating with high hardness, it is difficult to form unevenness and it is difficult to precisely control the shape of the formed unevenness. Further, as described in Japanese Patent Application Laid-Open No. 2004-29672 (Patent Document 7), the surface of chrome plating is often rough depending on the material and shape of the base, and the surface of the unevenness formed by blasting Since fine cracks generated by chrome plating are formed on the surface, there is a problem that it is difficult to design what kind of irregularities can be formed. Furthermore, since there are fine cracks generated by chrome plating, there is also a problem that the scattering characteristics of the finally obtained antiglare film change in an unfavorable direction. Furthermore, since the finished roll surface changes in various ways depending on the combination of the embossing roll base material surface and the plating type, in order to obtain the required surface irregularities accurately, the appropriate roll surface material and There was also a problem that an appropriate plating type had to be selected. Furthermore, even if the desired surface irregularity shape is obtained, the durability during use may be insufficient depending on the type of plating.

  Japanese Patent Laid-Open No. 2000-284106 (Patent Document 8) describes that after a sandblasting process is performed on a base material, an etching process and / or a thin film laminating process is performed, but metal plating is performed before the sandblasting process. Providing a layer is neither described nor suggested.

JP 2002-189106 A (Claims 1 to 6, paragraphs 0043 to 0046) JP-A-6-34961 (Claims 1 to 3, paragraph 0024) Japanese Patent Laying-Open No. 2004-45471 (Claim 4, Example 1) Japanese Patent Laying-Open No. 2004-45472 (Claim 4, Example 1) JP 2004-29240 A (Claim 2) JP-A-2004-90187 (Claims 1 and 2) JP 2004-29672 A (paragraph 0030) JP 2000-284106 A (Claim 7, paragraph 0006)

  The present invention provides a mold having a fine concavo-convex shape on the surface, useful for the production of an antiglare film exhibiting a high antiglare function, and a method for producing the mold, and further using the mold, Provided is a method for producing an anti-glare film that exhibits an excellent anti-glare function and is sufficiently prevented from being deteriorated in visibility due to whitening and does not cause glare when placed on the surface of a high-definition image display device. For the purpose. The present invention also provides a mold suitable for the production of an antiglare film without causing roughness on the chrome plated surface while adopting chromium plating having excellent hardness and surface gloss as the plating on the mold surface. An object of the present invention is to produce an antiglare film which is produced and exhibits an excellent antiglare function.

  As a result of intensive research to achieve the above-mentioned object, the present inventors applied copper plating or nickel plating as a base plating to the base material surface to be a mold, and formed irregularities by hitting fine particles on the plating surface. Then, after performing the process of dulling the concave and convex shape, it is found that if the concave and convex surface is subjected to chrome plating to obtain a mold, a mold having a desired fine concave and convex shape on the surface can be obtained with good reproducibility. It was. In addition, the anti-glare film with uneven surface obtained by transferring the uneven surface of the mold to the transparent resin film has sufficient anti-glare performance while being low haze, and when applied to an image display device, It has been found that a performance not exhibited in conventional products, such as whiteness and glare, and good visibility is exhibited. The present invention has been completed based on such findings and further various studies.

  That is, according to the present invention, the surface has a fine concavo-convex shape, the concavo-convex surface is composed of a chromium plating layer, and the concavo-convex surface is obtained by performing copper plating or nickel plating on the surface of the metal substrate. It is formed by polishing, bumping fine particles on the polished surface to form irregularities, dulling the irregular shape, and then applying chrome plating to the irregular surface, and The hardness is 800 Vickers hardness or more, the arithmetic average height Pa in an arbitrary cross section curve of the uneven surface is 0.01 μm or more and 0.5 μm or less, and the arithmetic average height Pa and average length PSm in the cross section curve A metal mold having a ratio Pa / PSm of 0.001 or more and 0.012 or less is provided.

  In producing this mold, it is advantageous to employ an etching process or copper plating for the process of dulling the uneven shape formed by hitting fine particles. When the etching process is employed, the etching amount is preferably 1 μm or more and 50 μm or less, and more preferably 1 μm or more and 20 μm or less. Moreover, when employ | adopting copper plating, it is preferable that the thickness is 1 to 20 micrometer, Furthermore, it is 1 to 10 micrometer.

  In this mold, the surface chromium plating layer preferably has a thickness of 1 μm to 20 μm, more preferably 1 μm to 10 μm. If the mold is formed in a roll shape and a fine uneven shape is formed on the surface thereof, the antiglare film can be produced in a continuous long roll shape.

  Further, according to the present invention, the surface of the base material is subjected to copper plating or nickel plating, the plating surface is polished, fine particles are applied to the polished surface to form irregularities, and the irregularity shape is blunted. Thereafter, the concavo-convex surface is subjected to chromium plating, so that the surface hardness is 800 or more in terms of Vickers hardness, and the arithmetic average height Pa in an arbitrary cross-sectional curve of the concavo-convex surface is 0.01 μm or more and 0.5 μm or less, A method for producing a metal mold in which the ratio Pa / PSm of the arithmetic average height Pa to the average length PSm in the cross-sectional curve is 0.001 or more and 0.012 or less is also provided.

  In this method, it is advantageous to employ an etching process or copper plating for the process of dulling the uneven shape formed by hitting fine particles. When the etching process is employed, the etching amount is preferably 1 μm or more and 50 μm or less, and more preferably 1 μm or more and 20 μm or less. Moreover, when employ | adopting copper plating, it is preferable that the thickness is 1 to 20 micrometer, Furthermore, it is 1 to 10 micrometer.

  In this method, it is advantageous to use the chrome-plated surface as it is as an uneven surface of the mold without polishing the surface after chrome plating. The chrome plating preferably has a thickness of 1 μm to 20 μm, and more preferably 1 μm to 10 μm.

  Further, according to the present invention, by using one of the above-described molds, the uneven surface of the mold is transferred to a transparent resin film, and then the transparent resin film having the transferred uneven surface is peeled off from the mold. A method for producing a glare film is also provided. Copper plating or nickel plating is applied to the substrate surface, the plated surface is polished, fine particles are applied to the polished surface to form irregularities, and the irregular shape is blunted. Applying chromium plating of hardness 800 or more, the arithmetic average height Pa in an arbitrary cross-section curve of the uneven surface is 0.01 μm or more and 0.5 μm or less, and the arithmetic average height Pa and average length PSm in the cross-section curve The mold has a ratio Pa / PSm of 0.001 or more and 0.012 or less, and the mold is used to transfer the concavo-convex surface to a transparent resin film. If it peels from a type | mold, the anti-glare film which has the outstanding anti-glare performance can be manufactured advantageously.

  The transparent resin film that transfers the uneven surface of the mold consists of a transparent base film with a photocurable resin layer formed on it, and is cured while pressing the photocurable resin layer against the uneven surface of the mold. By doing so, the uneven surface of the mold can be transferred to the photocurable resin layer.

  Since the metal mold of the present invention has a fine concavo-convex shape formed on the surface, the metal mold is useful for producing an antiglare film exhibiting a high antiglare function. According to the present invention, such a mold can be manufactured with good reproducibility. Furthermore, according to the manufacturing method of the anti-glare film of the present invention, anti-glare performance such as anti-reflection, anti-reflection, suppression of whitish and prevention of glare generation while keeping the brightness of the display image with low haze. An excellent antiglare film can be produced industrially advantageously.

  Hereinafter, preferred embodiments of the present invention will be described in detail. In the present invention, in order to obtain a metal mold having irregularities, the surface of the base material is subjected to copper plating or nickel plating, and after polishing the plated surface, fine particles are applied to the polished surface to form irregularities. After the uneven shape is dulled, the uneven surface is subjected to chromium plating, the mold surface hardness is 800 or more in terms of Vickers hardness, and the arithmetic average height Pa in an arbitrary cross-sectional curve of the uneven surface is 0. The mold has a ratio Pa / PSm of 0.001 to 0.012 in which the ratio Pa / PSm of the arithmetic average height Pa to the average length PSm in the cross-sectional curve is 0.001 to 0.5 μm.

  First, bumps are formed to form irregularities, and the surface of the substrate on which the chromium plating layer is formed is subjected to copper plating or nickel plating. Thus, by performing copper plating or nickel plating on the surface of the base material constituting the mold, it is possible to improve the adhesion and gloss of chromium plating in the subsequent process. When chromium plating is applied to the surface of iron, etc., or when chrome plating is applied again after forming unevenness on the chromium plating surface by the sandblasting method or the bead shot method, it was described in the background section above. As described above, the surface is easily roughened, fine cracks are generated, and the uneven shape on the surface of the mold becomes difficult to control. On the other hand, it has been found that such inconvenience is eliminated by applying copper plating or nickel plating to the surface. This is because copper plating and nickel plating have a high covering property and a strong smoothing action, so that a flat and glossy surface is formed by filling minute irregularities and nests of the metal substrate. These copper plating and nickel plating characteristics eliminate the rough surface of the chromium plating that may be caused by minute irregularities and nests that existed on the base material, and the high coverage of copper plating and nickel plating. Therefore, it is considered that the occurrence of fine cracks is reduced.

  Copper or nickel as used herein may be a pure metal of each, or may be an alloy mainly composed of copper or an alloy mainly composed of nickel. Therefore, the term “copper” as used herein means to include copper and a copper alloy, and nickel means to include nickel and a nickel alloy. Copper plating and nickel plating may be performed by electrolytic plating or electroless plating, respectively, but electrolytic plating is usually employed.

  Examples of the metal material suitable for forming the mold include aluminum and iron from the viewpoint of cost. Furthermore, lightweight aluminum is more preferable from the convenience of handling. The aluminum and iron here may be pure metals, respectively, or may be an alloy mainly composed of aluminum or iron. After applying copper plating or nickel plating to the surface of such a base material and further polishing the surface to obtain a smoother and more glossy surface, fine irregularities are formed by hitting fine particles on the surface, Further, after the processing of dulling the uneven shape, chrome plating was performed so that the Vickers hardness was 800 or more, and the arithmetic average height Pa in an arbitrary cross-sectional curve of the uneven surface was 0.01 μm or more. The mold has a ratio Pa / PSm of 0.001 to 0.012 in which the ratio Pa / PSm of the arithmetic average height Pa to the average length PSm in the sectional curve is 0.5 μm or less.

  When copper plating or nickel plating is performed, if the plating layer is too thin, the influence of the underlying surface cannot be completely eliminated, so that the thickness is preferably 10 μm or more. The upper limit of the plating layer thickness is not critical, but generally about 500 μm is sufficient from the viewpoint of cost and the like.

  The shape of the mold may be a flat plate or a columnar or cylindrical roll. If a metal mold | die is produced using a roll-shaped base material, an anti-glare film can be manufactured in a continuous roll shape.

  FIG. 1 is a cross-sectional view schematically showing a process until a metal mold is obtained, using a flat plate as an example. FIG. 1A shows a cross section of the substrate 41 after copper plating or nickel plating and mirror polishing, and the surface thereof is formed by a polishing surface 42 of a plating layer. Irregularities are formed on the surface of the substrate after such mirror polishing by hitting fine particles. FIG. 1B is a schematic cross-sectional view of the substrate 41 after hitting the fine particles. The fine concave surface 43 having a partial spherical shape is formed by hitting the fine particles. FIG. 1C is a schematic cross-sectional view of the substrate 41 after the surface on which the unevenness due to the fine particles has been formed is subjected to the process of dulling the uneven shape, and the left side is a state dulled by copper plating. Further, the right side shows the state of being blunted by the etching process. In the example employing the left copper plating, the copper plating layer 45 is formed on the concave surface 43 shown in (B), thereby forming a shape 50a in which acute projections on the partial spherical surface are blunted. . On the other hand, in the example employing the etching process on the right side, the concave surface 43 and the acute protrusion shown in (B) are shaved by etching to form a shape 50b in which the acute protrusion on the partial spherical surface is blunted. ing.

  Then, the uneven | corrugated shape of the surface is further blunted by giving chromium plating. (D) of FIG. 1 is a schematic cross-sectional view after performing chrome plating, the left side is a state in which the left side of (C) is subjected to chrome plating, and the right side is a state in the right side of (C). Is chrome-plated. In the example employing the left copper plating, the copper plating layer 45 is formed on the fine concave surface formed on the substrate 41, and the chromium plating layer 44 is further formed thereon, and the surface 46 is made of chromium. By plating, the surface is further dull than the concave surface 50a of (C), in other words, the uneven shape is relaxed. Also in the example employing the right etching process, the chromium plating layer 44 is formed on the surface 50b that has been blunted by the etching shown on the right side of FIG. Compared with the concave surface 50b, the chrome plating is further dulled, in other words, the concavo-convex shape is relaxed. In this way, after forming irregularities by hitting fine particles on the surface of the base material, the flat surface is substantially flattened by applying chromium plating to the concave surface 50 (50a or 50b) subjected to the process of dulling the irregularities. No metal mold can be obtained. In addition, such a mold is suitable for obtaining an antiglare film exhibiting preferable optical characteristics.

  The substrate surface made of copper plating or nickel plating is hit with fine particles in a state where the surface is polished, but it is particularly preferable that the surface is polished close to a mirror surface. This is because metal plates and metal rolls that are base materials are often subjected to machining such as cutting and grinding in order to achieve a desired accuracy, and as a result, processed marks remain on the surface of the base material. Because. Even in the state where copper plating or nickel plating is applied, those processed marks may remain, and the surface may not be completely smooth in the plated state. In the state where deep processed eyes remain, even if the surface of the substrate is deformed by hitting the fine particles, the unevenness such as the processed eyes may be deeper than the unevenness formed by the fine particles, and the effects of the processed eyes remain. there is a possibility. When an antiglare film is produced using such a mold, the optical properties may be unexpectedly affected.

  There is no particular limitation on the method of polishing the surface of the substrate on which plating has been performed, and any of mechanical polishing, electrolytic polishing, and chemical polishing can be used. Examples of the mechanical polishing method include super finishing, lapping, fluid polishing, and buff polishing. The surface roughness after polishing is represented by a center line average roughness Ra, and Ra is preferably 0.5 μm or less, and more preferably Ra is 0.1 μm or less. If Ra is too large, even if the metal surface is deformed by hitting fine particles, the influence of the surface roughness before deformation may remain, which is not preferable. Further, the lower limit of Ra is not particularly limited, and there is no need to specify it because there is a natural limit from the viewpoint of processing time and processing cost.

  As a method for hitting the surface of the substrate plated with fine particles, an injection processing method is preferably used. Examples of the injection processing method include a sand blast method, a shot blast method, and a liquid honing method. The particles used in these processes are preferably in a shape close to a sphere rather than a shape having sharp corners, and particles of a hard material that are crushed during processing and do not produce sharp corners are preferable. . As particles satisfying these conditions, spherical zirconia beads and alumina beads are preferably used for ceramic particles. For metal particles, beads made of steel or stainless steel are preferred. Furthermore, particles in which ceramic or metal particles are supported on a resin binder may be used.

  By using fine particles having an average particle diameter of 10 to 200 μm, particularly spherical fine particles, as the fine particles that strike the surface of the substrate plated, an anti-glare film exhibiting excellent anti-glare performance can be produced. If the average particle size of the fine particles is smaller than 10 μm, it will be difficult to form sufficient irregularities on the surface of the substrate plated, and sufficient antiglare performance will be difficult to obtain. On the other hand, if the average particle size of the fine particles is larger than 200 μm, the surface irregularities become rough, and glare occurs or the texture is lowered. Here, when processing using fine particles having an average particle size of 15 μm or less, it is preferable to employ a wet blasting method in which the particles are processed by being dispersed in a suitable dispersion medium so that the particles do not aggregate due to static electricity or the like.

Further, the pressure at the time of hitting the fine particles and the use amount of the fine particles also affect the uneven shape after processing, and eventually the surface shape of the antiglare film, but generally the gauge pressure is about 0.01 to 0.5 MPa. What is necessary is just to select suitably from the amount of microparticles | fine-particles of about 4-30g per 1 cm < ² > of surface area of the pressure and metal to process according to the kind and particle size of a microparticle to be used, the kind of metal, desired uneven | corrugated shape, etc.

  The concavo-convex shape formed by hitting fine particles on the surface of the substrate plated has an arithmetic average height Pa of an arbitrary cross-sectional curve of 0.1 μm to 1 μm, and the arithmetic average height of the cross-sectional curve The ratio Pa / PSm between Pa and the average length PSm is preferably 0.01 or more and 0.06 or less. When the arithmetic average height Pa is smaller than 0.1 μm or the ratio Pa / PSm is smaller than 0.01, the uneven surface is almost flat when the uneven shape is blunted before the chrome plating process. Thus, a mold having a desired surface shape cannot be obtained. Further, when the arithmetic average height Pa is larger than 1 μm or the ratio Pa / PSm is larger than 0.06, the process of dulling the concavo-convex shape before chrome plating must be performed under strong conditions, and the surface shape It becomes difficult to control.

  Thus, the process which blunts an uneven | corrugated shape is given to the base material in which the unevenness | corrugation was formed in the copper plating or nickel plating surface. As the process of dulling the uneven shape, as described above with reference to FIGS. 1C and 1D, etching treatment or copper plating is preferable. By performing the etching process, the sharp portion of the uneven shape produced by hitting the fine particles is eliminated. Thereby, the optical characteristic of the anti-glare film produced when it uses as a metal mold | die changes in a preferable direction. Moreover, since copper plating has a strong smoothing action, the effect of dulling the uneven shape is stronger than chromium plating. Thereby, the optical characteristic of the anti-glare film produced when it uses as a metal mold | die changes in a preferable direction.

Etching is usually performed by corroding the surface using ferric chloride (FeCl ₃ ), cupric chloride (CuCl ₂ ), alkaline etchant (Cu (NH ₃ ) ₄ Cl ₂ ), or the like. However, a strong acid such as hydrochloric acid or sulfuric acid can be used, or reverse electrolytic etching by applying a potential opposite to that during electrolytic plating can be used. The degree of unevenness after etching is different depending on the type of underlying metal and the size and depth of the unevenness obtained by blasting techniques. The largest factor is the etching amount. The etching amount here is the thickness of the base material to be cut by etching. If the etching amount is small, the effect of dulling the surface shape of the unevenness obtained by a technique such as blasting is insufficient, and the optical characteristics of the antiglare film obtained by transferring the uneven shape to a transparent film are not so good. . On the other hand, when the etching amount is too large, the uneven shape is almost lost and the die is almost flat, so that the antiglare property is not exhibited. Therefore, the etching amount is preferably 1 μm or more and 50 μm or less, and more preferably 20 μm or less.

  When copper plating is used as the dulling process, the unevenness of the unevenness varies depending on the type of base metal, the size and depth of the unevenness obtained by techniques such as blasting, and the type and thickness of the plating. Although it cannot be said, the greatest factor in controlling the degree of rounding is the plating thickness. If the thickness of the copper plating layer is thin, the effect of dulling the surface shape of the unevenness obtained by techniques such as blasting is insufficient, and the optical properties of the antiglare film obtained by transferring the uneven shape to a transparent film are insufficient. It doesn't get much better. On the other hand, when the plating thickness is too thick, the productivity is deteriorated and the uneven shape is almost lost, so that the antiglare property is not exhibited. Therefore, the thickness of the copper plating is preferably 1 μm or more and 20 μm or less, and more preferably 10 μm or less.

  In this way, after dulling the surface shape of the substrate on which the unevenness is formed on the copper plating or nickel plating surface, the surface of the unevenness is further dulled and further the surface hardness is increased by applying chrome plating. Make a metal plate. The degree of unevenness at this time also differs depending on the type of base metal, the size and depth of the unevenness obtained by techniques such as blasting, and the type and thickness of the plating. The greatest factor in controlling is the plating thickness. If the thickness of the chrome plating layer is thin, the effect of dulling the surface shape of the unevenness obtained before the chrome plating process is insufficient, and the optical characteristics of the antiglare film obtained by transferring the uneven shape to a transparent film are It doesn't get much better. On the other hand, when the plating thickness is too thick, productivity is deteriorated and a protruding plating defect called a nodule is generated. Therefore, the thickness of the chrome plating is preferably 1 μm or more and 20 μm or less, and more preferably 10 μm or less.

  The concavo-convex shape on the surface of the metal plate after the chrome plating has an arithmetic average height Pa of 0.01 μm or more and 0.5 μm or less in an arbitrary cross section curve, and the arithmetic average height Pa and average length in the cross section curve. The PSm ratio Pa / PSm is preferably 0.001 or more and 0.012 or less. When the arithmetic average height Pa is less than 0.01 μm or the ratio Pa / PSm is less than 0.001, the surface shape of the antiglare film produced using this mold is almost flat, and is sufficient. No antiglare performance. In addition, when the arithmetic average height Pa is as large as 0.5 μm or the ratio Pa / PSm is greater than 0.012, the antiglare film produced using this mold becomes white or glaring occurs. Or the texture is degraded.

In the present invention, a chrome plating that has a glossy surface, a high hardness, a low friction coefficient, and good releasability is employed on the surface of a flat plate or a roll. The type of chrome plating is not particularly limited, but it is preferable to use a chrome plating that expresses a good gloss, so-called gloss chrome plating or decorative chrome plating. Chromium plating is usually performed by electrolysis, and an aqueous solution containing chromic anhydride (CrO ₃ ) and a small amount of sulfuric acid is used as the plating bath. By adjusting the current density and electrolysis time, the thickness of the chromium plating can be controlled.

  The Vickers hardness of the chromium plating applied to the mold surface is preferably 800 or more, more preferably 1000 or more. If the Vickers hardness is low, the durability when using the mold will be lowered, and the decrease in hardness due to chrome plating is likely to cause abnormalities in the plating bath composition, electrolysis conditions, etc. during plating treatment, There is a high possibility that the occurrence of defects will have an undesirable effect.

  Patent Document 1, Patent Document 4, Patent Document 6 and the like listed in the Background Art section disclose the use of chrome plating, but depending on the type of the base and the chrome plating before the metal plating, In many cases, the surface is roughened after plating or a lot of minute cracks are generated by chrome plating, and as a result, the optical characteristics of the produced antiglare film proceed in an unfavorable direction. Those having a rough plated surface are not suitable for metal molds for anti-glare films. This is because the plating surface is generally polished after chrome plating in order to eliminate roughness, but as described later, polishing of the surface after plating is not preferable in the present invention. In the present invention, such inconvenience that is likely to occur in chromium plating is eliminated by applying copper plating or nickel plating to the base metal.

  In the case where the process of dulling the concavo-convex shape is not performed before the chrome plating, the chrome plating must be thickened in order to sufficiently dull the sharp portion of the concavo-convex shape produced by hitting fine particles. However, if the thickness of the chrome plating is too thick, nodules are likely to be generated, which is not preferable. In addition, when the thickness of the chrome plating is reduced, the uneven shape produced by hitting the fine particles cannot be sufficiently dulled, and a mold having the desired surface shape cannot be obtained. The produced anti-glare film does not exhibit excellent anti-glare performance.

  Patent Document 1 describes that a chrome-plated roller is formed on a surface of iron by forming a concavo-convex surface by a sandblasting method or a bead shot method, and Patent Document 2 describes etching, sandblasting, etc. on a metal surface. It is described that unevenness is formed by the above method, and Patent Documents 5 and 6 describe that a bead shot method or a blasting process is performed on the roll surface. However, after forming a concavo-convex shape by hitting fine particles as in the method shown in the present invention, after applying a process of actively dulling the surface shape, a method of applying a chrome plating process to dull the surface concavo-convex shape According to the study by the present inventors, an anti-glare film exhibiting excellent anti-glare performance unless the surface shape is actively dulled as in the method shown in the present invention. Could not be manufactured.

  In addition, it is not preferable to perform plating other than chromium plating on the metal surface with unevenness. This is because plating other than chromium has low hardness and wear resistance, so that the durability as a mold is lowered, and unevenness is worn away during use or the mold is damaged. In an antiglare film obtained from such a mold, there is a high possibility that a sufficient antiglare function cannot be obtained, and there is a high possibility that defects will occur on the film.

  Polishing the surface after plating as disclosed in Patent Document 6 is also not preferable in the present invention. By polishing, a flat portion is generated on the outermost surface, which may cause deterioration of optical characteristics, and because shape control factors increase, it becomes difficult to control the shape with good reproducibility. It is. FIG. 2 is a schematic cross-sectional view of a metal plate in which a flat surface is produced when a chrome-plated surface is polished after the uneven surface obtained by hitting fine particles is subjected to a process of dulling the uneven shape. Specifically, this corresponds to a state in which the surface of the chromium plating layer 44 is polished from the state of FIG. Due to the polishing, some of the protrusions of the surface unevenness 46 of the chromium plating layer 44 formed on the surface of the metal 41 are scraped to produce a flat surface 48.

  Next, the process of manufacturing an anti-glare film using the metal mold obtained in this way will be described. An antiglare film is obtained by transferring the shape of the metal mold obtained by the method described above to a transparent resin film. The transfer to the mold-shaped film is preferably performed by embossing. Examples of embossing include a UV embossing method using a photocurable resin and a hot embossing method using a thermoplastic resin.

  In the UV embossing method, a photocurable resin layer is formed on the surface of a transparent substrate film, and the photocurable resin layer is cured while pressing the photocurable resin layer against the metal surface. Transferred to the resin layer. Specifically, an ultraviolet curable resin is applied on a transparent base film, and the applied ultraviolet curable resin is in close contact with a metal mold, and ultraviolet rays are irradiated from the transparent base film side. The shape of the metal mold is transferred to the ultraviolet curable resin by curing the ultraviolet curable resin and then peeling the transparent substrate film on which the cured ultraviolet curable resin layer is formed from the metal mold. The kind of ultraviolet curable resin is not particularly limited. Moreover, although expressed as an ultraviolet curable resin, a resin that can be cured even by visible light having a wavelength longer than that of ultraviolet rays can be obtained by appropriately selecting a photoinitiator. That is, the term “ultraviolet curable resin” as used herein is a generic name including such a visible light curable resin. On the other hand, in the hot embossing method, a transparent thermoplastic resin film is pressed against a metal mold in a heated state, and the surface shape of the mold is transferred to the thermoplastic resin film. Among these embossing methods, the UV embossing method is preferable from the viewpoint of productivity.

  The transparent substrate film that can be used for the production of the antiglare film may be substantially optically transparent, and examples thereof include resin films such as a triacetyl cellulose film and a polyethylene terephthalate film.

  A commercially available product can be used as the ultraviolet curable resin. For example, polyfunctional acrylates such as trimethylolpropane triacrylate and pentaerythritol tetraacrylate are used alone or in admixture of two or more thereof, and “Irgacure 907”, “Irgacure 184” (above, Ciba A product obtained by mixing a photopolymerization initiator such as “Specialty Chemicals” or “Lucirin TPO” (BASF) can be used as an ultraviolet curable resin.

  The thermoplastic transparent resin film used in the hot embossing method may be any film as long as it is substantially transparent. For example, polymethyl methacrylate, polycarbonate, polyethylene terephthalate, triacetyl cellulose, norbornene compounds A solvent cast film or an extruded film of a thermoplastic resin such as amorphous cyclic polyolefin as a monomer can be used. These transparent resin films can also be transparent substrate films when the UV embossing method described above is employed.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the following examples, the metal mold or the antiglare film is evaluated as follows.

(Measurement of Vickers hardness)
Vickers hardness was measured by a method based on JIS Z 2244 using an ultrasonic hardness tester “MIC10” manufactured by Krautkramer. The measurement was performed on the surface of the mold itself.

(Measurement of arithmetic average height Pa and average length PSm in the section curve)
Since a roll-shaped mold is produced, it is difficult to directly measure the surface shape. Therefore, using the mold, an antiglare film was prepared in the same manner as in Example 1 described later, and the surface shape of the antiglare film was measured by the following method to obtain the surface shape of each mold. . The cross-sectional curve on the antiglare film is one in which the top and bottom of the cross-sectional curve on the mold are inverted, but the arithmetic average height Pa and the average length PSm are the same in both cases. In measuring the surface shape, a confocal microscope “PLμ2300” manufactured by Sensofar was used. And in order to prevent the curvature of a sample, it bonded to the glass substrate so that an uneven surface might become the surface using an optically transparent adhesive, and it used for the measurement. At the time of measurement, the magnification of the objective lens was 50 times. Based on the measurement data, the arithmetic average height Pa and the average length PSm were determined by calculation using a method based on JIS B 0601.

(Measurement of haze)
The haze of the antiglare film was measured by the method specified in JIS K 7136. Specifically, haze was measured using a haze meter “HM-150” manufactured by Murakami Color Research Laboratory Co., Ltd., which conforms to this standard. Also in this case, in order to prevent the sample (antiglare film) from warping, it was subjected to measurement after being bonded to a glass substrate using an optically transparent pressure-sensitive adhesive so that the uneven surface becomes the surface. In general, when haze increases, an image becomes dark when applied to an image display device, and as a result, front contrast tends to decrease. Therefore, a lower haze is preferable.

(Measurement of reflection sharpness)
The reflection definition was measured by the method specified in JIS K 7105. Specifically, the reflection sharpness of the antiglare film was measured using an image clarity measuring device “ICM-1DP” manufactured by Suga Test Instruments Co., Ltd. in accordance with this standard. In this standard, four types of optical combs are used for measuring the image sharpness: the ratio of the width of the dark part to the bright part is 1: 1, and the widths are 0.125 mm, 0.5 mm, 1.0 mm, and 2.0 mm. Is stipulated. Among these, when an optical comb with a width of 0.125 mm is used, the measurement error when using an optical comb with a width of 0.125 mm is large because an error in the measured value becomes large in the antiglare film defined in the present invention. The value is not added to the sum, and the sum of image sharpness measured using three types of optical combs having widths of 0.5 mm, 1.0 mm, and 2.0 mm is referred to as reflection sharpness. In this definition, the maximum value of the reflection definition is 300%. If the definition of reflection definition is too large, an image of a light source or the like is reflected and the antiglare property tends to decrease. Therefore, it is preferably 100% or less, and more preferably 50% or less. . In the evaluation, in order to prevent the sample from warping and to prevent reflection from the back surface, an optically transparent adhesive is used to make the uneven surface of the antiglare film 2 mm thick. After being pasted on the black acrylic resin plate, it was subjected to measurement. In this state, light was incident from the sample (antiglare film) side and measurement was performed.

(Measurement of 60 degree glossiness)
The 60 degree glossiness was measured by the method specified in JIS Z 8741. Specifically, the glossiness of the antiglare film was measured using a gloss meter “PG-1M” manufactured by Nippon Denshoku Industries Co., Ltd., which conforms to this standard. Also in this case, in order to prevent the sample from warping and to prevent reflection from the back surface, the antiglare film is black with a thickness of 2 mm so that the uneven surface becomes the surface using an optically transparent adhesive. It bonded to the acrylic resin board, and used for the measurement. In this state, light was incident from the sample (antiglare film) side and measurement was performed. Generally, when the glossiness at 60 degrees is small, it means that the sample surface is cloudy, and as a result, whitening is likely to occur. Therefore, it is preferable that the glossiness is high. However, if the glossiness is too high, reflection occurs and the antiglare property is lowered. Therefore, a value of about 30 to 90% is preferable.

(Visual evaluation of reflection and whitishness)
In order to prevent reflection from the back surface of the antiglare film, the antiglare film is bonded to the black acrylic resin plate so that the uneven surface becomes the surface, and visually observed from the uneven surface side in a bright room with a fluorescent lamp. Then, the presence or absence of reflection of a fluorescent lamp and the degree of whitening were visually evaluated. Reflection and whitishness were evaluated according to the following criteria in three stages from 1 to 3.

Reflection 1: Reflection is not observed,
2: Reflection is slightly observed,
3: Reflection is clearly observed.

White 1: The white is not observed,
2: A little whitish is observed,
3: The whitish is clearly observed.

(Evaluation of glare)
The glare was evaluated by the following method. First, a photomask having a unit cell pattern as shown in a plan view in FIG. 3 was prepared. In this figure, a unit cell 60 has a key-shaped chrome light shielding pattern 61 with a line width of 10 μm formed on a transparent substrate, and an opening 62 is a portion where the chrome light shielding pattern 61 is not formed.

  Next, as shown in FIG. 4, this photomask is placed in a light box 65 with the chrome light-shielding pattern 61 of the photomask 63 facing up, and an antiglare film with a 20 μm thick adhesive on a 1.1 mm thick glass plate 67. The sample to which 70 was bonded was placed on the photomask 63 and visually observed from a location 39 about 30 cm away from the sample, whereby the degree of glare was sensory evaluated in seven stages. A light source 66 is disposed in the light box 65. Of the seven stages of sensory evaluation, level 1 corresponds to a state where no glare is observed, level 7 corresponds to a state where severe glare is observed, and level 3 refers to a state where only slight glare is observed. Note that the unit cell of the photomask was a unit cell length × unit cell width in FIG. 3 of 282 μm × 94 μm, and therefore the opening length × opening width in the drawing was 272 μm × 84 μm. This cell corresponds to a pixel density of 90 ppi (pixel per inch).

[Example 1]
A 200 mm diameter iron roll (JIS STKM13A) with a copper ballad plated surface was prepared. The copper ballad plating consists of a copper plating layer / thin silver plating layer / surface copper plating layer, and the thickness of the entire plating layer was about 200 μm. The copper-plated surface is mirror-polished, and the blasting device (Fuji Seisakusho Co., Ltd.) is used on the polished surface. 125 μm) was blasted at a blast pressure of 0.05 MPa (gauge pressure, the same applies hereinafter) and a use amount of beads of 8 g / cm ² (amount used per 1 cm ² of surface area of the roll, the same applies hereinafter) to give unevenness to the surface. The resulting copper-plated iron roll with unevenness was etched with a cupric chloride solution. The etching amount at that time was set to 2 μm. Thereafter, chrome plating was performed to produce a metal mold. At this time, the chromium plating thickness was set to 6 μm.

Separately, a photocurable resin composition “GRANDIC 806T” (trade name) manufactured by Dainippon Ink & Chemicals, Inc. is dissolved in ethyl acetate to obtain a 50% strength by weight solution, which is a photopolymerization initiator. “Lucirin TPO” (manufactured by BASF, chemical name: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) was added at 5 parts by weight per 100 parts by weight of the curable resin component to prepare a coating solution. This coating solution was applied onto a 80 μm thick triacetylcellulose (TAC) film so that the coating thickness after drying was 5 μm, and dried for 3 minutes in a drier set at 60 ° C. The dried film was brought into close contact with the uneven surface of the metal mold produced above with a rubber roll so that the photocurable resin composition layer was on the mold side. In this state, light from a high-pressure mercury lamp having an intensity of 20 mW / cm ² was irradiated from the TAC film side so that the amount of light in terms of h-line was 200 mJ / cm ² to cure the photocurable resin composition layer. Thereafter, the TAC film was peeled from the mold together with the cured resin to obtain a transparent antiglare film comprising a laminate of the cured resin having irregularities on the surface and the TAC film.

  The optical properties and antiglare performance of the obtained antiglare film were evaluated by the methods described above. The production conditions of the mold and the surface properties (Vickers hardness, surface shape immediately after blasting and after chrome plating) are shown in Table 1, and the optical characteristics and antiglare performance of the antiglare film are shown in Table 2, respectively. The breakdown of the reflection definition in Table 2 is as follows.

Reflection sharpness 0.5mm Optical comb: 11.1%
1.0mm optical comb: 12.5%
2.0mm optical comb: 30.2%
Total 53.8%

[Examples 2 to 5]
The metal mold manufacturing conditions were changed as shown in Table 1, and the other processes were performed in the same manner as in Example 1 to manufacture a metal mold having irregularities on the surface. Using the mold, a transparent antiglare film made of a laminate of a cured resin having irregularities on the surface and a TAC film was produced in the same manner as in Example 1. The production conditions and surface properties of the mold are shown in Table 1, and the optical characteristics and antiglare performance of the obtained antiglare film are shown in Table 2, respectively.

[Example 6]
Copper plating was performed as a process for blunting the concavo-convex shape formed by blasting, and other processes were performed in the same manner as in Example 1 to prepare a metal mold having concavo-convex on the surface. In addition, the plating thickness of the copper plating when dulling the concavo-convex shape after blasting was set to 2 μm. Using the mold, a transparent antiglare film made of a laminate of a cured resin having irregularities on the surface and a TAC film was produced in the same manner as in Example 1. The production conditions and surface properties of the mold are shown in Table 1, and the optical characteristics and antiglare performance of the obtained antiglare film are shown in Table 2, respectively.

[Comparative Example 1]
The metal mold which has an unevenness | corrugation on the surface was produced like Example 1 except not performing the process which blunts the uneven | corrugated shape formed by blasting. Using the mold, a transparent antiglare film made of a laminate of a cured resin having irregularities on the surface and a TAC film was produced in the same manner as in Example 1. The production conditions and surface properties of the mold are shown in Table 1, and the optical characteristics and antiglare performance of the obtained antiglare film are shown in Table 2, respectively.

  As shown in Table 2, the antiglare film produced using the mold of the present invention has low haze, and also has the performances of preventing reflection, preventing whitening, and preventing glare. On the other hand, as in Comparative Example 1, when the surface shape is not blunted, the haze is higher than that obtained by the method of the present invention, and the whitish state is clearly observed. Met. This is because the effect of dulling the surface unevenness shape is not sufficiently exhibited only by the chrome plating process. This also shows that the value of Pa / PSm after chromium plating in the mold of Comparative Example 1 is 0.015, which is larger than that of the example.

It is a cross-sectional schematic diagram which shows the manufacturing method of the metal mold | die which concerns on this invention for every process. It is a cross-sectional schematic diagram which shows the state which grind | polished the surface after chromium plating. It is a top view which shows the unit cell of the pattern for glare evaluation. It is a cross-sectional schematic diagram which shows the state of glare evaluation.

Explanation of symbols

41 …… Metal substrate,
42 …… Polished surface,
43 ...... Concave surface formed by hitting fine particles,
44 …… Chrome plating layer,
45 …… Copper plating layer,
46 .. Uneven surface remaining after plating,
48 ...... Flat surface generated when the surface after plating is polished,
50a: a surface in which a concave surface formed by hitting fine particles is dulled by copper plating,
50b: a surface formed by etching a concave surface formed by hitting fine particles,
60 …… Photomask unit cell,
61 …… Photomask chrome shading pattern,
62 …… Photomask opening,
63 …… Photomask,
65 …… Light box,
66 …… Light source,
67 …… Glass plate,
69 …… A place to observe glare
70: Anti-glare film.

Claims (19)

  A mold having a fine concavo-convex shape on the surface, the concavo-convex surface is composed of a chromium plating layer, and the concavo-convex surface is subjected to copper plating or nickel plating on the surface of the metal substrate, and the plating surface is polished. It is formed by bumping fine particles on the polished surface to form unevenness, dulling the uneven shape, and then applying chromium plating to the uneven surface, and the hardness of the chromium plated surface is Vickers The hardness is 800 or more, the arithmetic average height Pa in an arbitrary cross-sectional curve of the uneven surface is 0.01 μm or more and 0.5 μm or less, and the ratio Pa / of the arithmetic average height Pa and the average length PSm in the cross-section curve A metal mold having a PSm of 0.001 or more and 0.012 or less.   The mold according to claim 1, wherein the process of dulling the uneven shape is performed by an etching process.   The mold according to claim 2, wherein the etching amount is 1 µm or more and 50 µm or less.   The metal mold according to claim 1, wherein the process of dulling the uneven shape is performed by copper plating.   The metal mold | die of Claim 4 in which the copper plating layer for blunting uneven | corrugated shape has thickness of 1 micrometer or more and 20 micrometers or less.   The mold according to any one of claims 1 to 5, wherein the chromium plating layer on the surface has a thickness of 1 µm to 20 µm.   The mold according to any one of claims 1 to 5, wherein the chromium plating layer on the surface has a thickness of 1 µm to 10 µm.   The mold according to any one of claims 1 to 7, which is in a roll shape and has a fine uneven shape on a surface thereof.   Copper plating or nickel plating is applied to the substrate surface, the plating surface is polished, fine particles are applied to the polished surface to form irregularities, and the irregular surface is dulled, and then the uneven surface is chromium plated A method for producing a metal mold, characterized in that   The method according to claim 9, wherein the process of dulling the uneven shape is performed by an etching process.   The method according to claim 10, wherein the etching amount is 1 μm or more and 50 μm or less.   The method according to claim 10, wherein the etching amount is 1 μm or more and 20 μm or less.   The method according to claim 9, wherein the process of dulling the uneven shape is performed by copper plating.   The method according to claim 13, wherein the copper plating layer for dulling the uneven shape has a thickness of 1 μm or more and 20 μm or less.   The method according to claim 13, wherein the copper plating layer for dulling the uneven shape has a thickness of 1 μm to 10 μm.   The method according to any one of claims 9 to 15, wherein the surface is not polished and the chrome plating surface is used as the concavo-convex surface of the mold as it is after chrome plating.   The method according to any one of claims 9 to 16, wherein the chromium plating is performed so that the thickness thereof is 1 µm or more and 20 µm or less.   The method according to any one of claims 9 to 16, wherein the chromium plating is performed so that the thickness thereof is 1 µm or more and 10 µm or less. The mold according to any one of claims 1 to 8, wherein the uneven surface of the mold is transferred to a transparent resin film, and then the transparent resin film having the transferred uneven surface is peeled off from the mold. A method for producing an antiglare film.

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