JP2010097105A - Polarizing plate, liquid crystal display apparatus, and ips mode liquid crystal display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing plate through which light does not break even when the polarizing plate is used at high temperature, for example, in the open air or even when the polarizing plate warmed by the heat generated from a backlight is viewed from the oblique direction and to provide an IPS (in-plane switching) mode liquid crystal display apparatus using the polarizing plate. <P>SOLUTION: The polarizing plate is obtained by layering, at the least, a first protective film, a polarizing film and a second protective film in this order. The second protective film is composed, at the least, of a transparent film and an optically anisotropic layer containing a substantially vertically-oriented polymerizable liquid crystal compound. The first protective film has, at the least, a void holding layer of ≥30% void ratio on the surface opposite to the polarizing film-layered surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polarizing plate and a liquid crystal display device using the same, and more particularly to a polarizing plate suitable for an IPS (in-plane switching) mode type liquid crystal display device.

  Commonly known TN type, STN type, OCB type, HAN type, VA type (PVA type, MVA type), IPS type, etc. are well known as the liquid crystal display device, and among them, IPS (in-plane switching) mode Type liquid crystal display device (hereinafter also referred to simply as IPS liquid crystal display device) includes a liquid crystal cell having a liquid crystal layer and a pair of substrates sandwiching the liquid crystal layer, a polarizing film, and a protective film in this order. In black display, the liquid crystal molecules of the liquid crystal layer are aligned in parallel with the surfaces of the pair of substrates, so that black display performance is excellent, and sufficient contrast is obtained when viewing the screen from the top, bottom, left, and right directions.

  However, when the screen is viewed from an oblique direction deviating from the top, bottom, left, and right, the transmitted light causes birefringence and the light leaks, so that sufficient black cannot be obtained and the contrast is lowered.

  For this reason, for example, in an IPS liquid crystal display device, optical compensation means is added to the liquid crystal display device with the following arrangement configuration to prevent light leakage of black display and contrast reduction when the screen is viewed from an oblique direction. Attempts to improve are being made.

For example, in an optical film that is laminated so that the absorption axis of the polarizing plate and the slow axis of the retardation film are orthogonal or parallel, the retardation film has a direction in which the in-plane refractive index in the film plane is maximized as the X axis. When the direction perpendicular to the X axis is the Y axis, the thickness direction of the film is the Z axis, and the refractive indexes in the respective axial directions are nx ₁ , ny ₁ , nz ₁ , and the film thickness d ₁ (nm) _{to, Nz = (nx 1 -nz 1} ) / Nz value represented by _{(nx 1} -ny 1) is satisfied 0.4-0.6, and in-plane retardation _{Re 1} = (nx 1 - An optical film having ny ₁ ) × d ₁ of 200 to 350 nm is held (for example, see Patent Document 1).

  The technology uses a thermoplastic resin film (polycarbonate film) as a retardation film (optical compensation film), thereby preventing light leakage of black display when viewed from an oblique direction, improving viewing angle and improving contrast. I am trying.

  In recent years, display devices have been used in public places called digital signage due to the expansion of applications of liquid crystal display devices, and there is a demand for liquid crystal display devices that can withstand outdoor use. When using a liquid crystal display device outdoors, it is necessary to increase the output of the backlight in order to obtain sufficient visibility in an environment with high (bright) illuminance in addition to severe temperature changes. It needs to be able to withstand.

  However, since the above-described technology produces an optical compensation film using only a thermoplastic film, when the temperature change is severe, when exposed to high heat, and when a high-power backlight is used. However, the unevenness of the phase difference becomes large due to the contraction or deformation due to heat, and as a result, there is a problem that the light leakage of black display when viewed from an oblique direction cannot be sufficiently prevented, and the viewing angle and contrast are lowered. In particular, an LED is recently used as a backlight of a liquid crystal display device. When an LED is used, the influence of heat unevenness generated by ON / OFF is further large, and black when viewed from an oblique direction. Prevention of light leakage of display and prevention of contrast reduction was insufficient.

  In addition, as a technique for preventing the viewing angle and the contrast from being lowered due to light leakage of black display when viewed from an oblique direction of the IPS liquid crystal display device, polymerization that is substantially vertically aligned on a biaxial retardation film is possible. A technique for laminating layers containing a conductive liquid crystal compound is known (for example, see Patent Document 2). In the technique described in Patent Document 2, a homeotropic alignment liquid crystal composition is applied onto a biaxial film on a substrate having a vertical alignment ability, and solidified or cured, whereby positive C on the retardation film. It is a manufacturing method of the positive C plate which forms a plate.

According to the technique described in Patent Document 2, although the thermal shrinkage and deformation can be reduced as compared with the technique of Patent Document 1, the substantially vertically aligned polymerizable liquid crystal compound has a large alignment due to the effect of slight curing shrinkage. Therefore, it is easy to cause disturbance of the phase difference, so that the light leakage prevention and the contrast reduction of the black display when viewed from the oblique direction are not satisfactory. Therefore, even when the temperature changes drastically outside and is exposed to high temperatures, or when a high-power backlight is used, it is possible to sufficiently suppress a decrease in viewing angle and contrast due to black display light leakage. There is a need for polarizing plates.
Japanese Patent Application Laid-Open No. 2004-4642 JP 2007-148099 A

  According to the technique described in Patent Document 2, although the thermal shrinkage and deformation can be reduced as compared with the technique of Patent Document 1, the substantially vertically aligned polymerizable liquid crystal compound has a large alignment due to the effect of slight curing shrinkage. Therefore, it is easy to cause disturbance of the phase difference, so that the light leakage prevention and the contrast reduction of the black display when viewed from the oblique direction are not satisfactory. Therefore, a polarizing plate that can sufficiently suppress a decrease in viewing angle and a decrease in contrast due to light leakage of black display when the temperature changes drastically outside and is exposed to high temperatures or when a high-power backlight is used. It has been demanded.

  Accordingly, an object of the present invention is to provide a polarizing plate that does not leak light even when viewed from an oblique direction due to heat applied for outdoor use, heat generated from a backlight, and an IPS liquid crystal display device using the same. It is to provide.

  As a result of intensive studies on the above problems, the present inventors have made a polarizing plate provided with an optically anisotropic layer containing a polymerizable liquid crystal compound substantially vertically aligned as a polarizing plate having an optical compensation function. By providing a layer having a void on the side opposite to the side where the optically anisotropic layer is provided, the temperature change is large, and when exposed to high temperature conditions or when a high output backlight is used. Even in such a case, it has been revealed that a polarizing plate can be obtained that can prevent light leakage of black display and can sufficiently suppress a decrease in viewing angle and a decrease in contrast.

  The details of the principle are not clear, but when exposed to high-temperature heating conditions, as described above, the alignment of the polymerizable liquid crystal compound in the optically anisotropic layer at the high temperature portion is disturbed and light leakage occurs. To do. On the other hand, a layer having a void (void retaining layer) functions as an antireflection layer by being provided on the film on the viewing side of the polarizing plate, but when exposed to high temperature heating conditions, By shrinking the resin constituting the holding layer, the porosity of the gap holding layer is substantially lowered and the refractive index is raised. Thereby, the reflectance of a space | gap holding layer changes and it raises partially. As a result of this partial increase in reflectivity, the effect of retardation unevenness of the optically anisotropic layer becomes difficult to understand, and it is assumed that light leakage is reduced.

  In addition, when a polymerizable liquid crystal compound is used for the optically anisotropic layer, there is a problem that the curling is strong and the wrinkles and unevenness of the lamination tend to occur when the polarizing plate is produced. However, a layer having voids should be provided on the outermost surface layer. Thus, it has been found that the curl can be balanced, and problems such as wrinkles and unevenness of the lamination can be solved when the polarizing plate is produced.

  The above object of the present invention is achieved by the following configurations.

  1. In a polarizing plate in which at least a first protective film, a polarizing film, and a second protective film are laminated in this order, the second protective film comprises at least a transparent film and a polymerizable liquid crystal compound that is substantially vertically aligned. A polarizing plate comprising an optically anisotropic layer including the first protective film and a void-holding layer having a porosity of at least 30% on the side far from the polarizing film.

  2. 2. The polarizing plate according to 1 above, wherein the gap retaining layer has a fine concavo-convex structure, and the period Pmax at the top of the fine concavo-convex structure is 380 nm or less.

  3. 3. The polarizing plate according to 2 above, wherein the outer peripheral surface of the fine concavo-convex structure has a cone shape having an inclination from the top to the bottom.

  4). 4. The polarizing plate according to 3 above, wherein the cone shape is an elliptical cone shape or an elliptical truncated cone shape.

  5. 5. The polarizing plate according to any one of 1 to 4, wherein the void retaining layer contains a cationic polymerization compound.

  6). 6. A liquid crystal display device using the polarizing plate according to any one of 1 to 5 on at least one surface of a liquid crystal cell.

  7). 6. An IPS (in-plane switching) mode liquid crystal display device, wherein the polarizing plate according to any one of 1 to 5 is used on at least one surface of an IPS (in-plane switching) mode liquid crystal cell. .

  According to the present invention, there are provided a polarizing plate which does not leak light even when viewed from an oblique direction due to heat applied under outdoor use, heat generated from a backlight, and an IPS liquid crystal display device using the same. be able to.

  In addition, it is possible to provide a polarizing plate that does not cause wrinkles or unevenness during the production of a polarizing plate that is generated by curling when a polymerizable liquid crystal compound is used for the optically anisotropic layer.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

  The polarizing plate of the present invention is a polarizing plate in which at least a first protective film, a polarizing film, and a second protective film are laminated in this order, and the second protective film is at least a transparent film and substantially vertical. It is composed of an optically anisotropic layer containing an oriented polymerizable liquid crystal compound, and the first protective film has a void holding layer having a porosity of at least 30% on the side far from the polarizing film.

<Porosity>
One feature of the present invention is that the void ratio of the void retaining layer provided on the first protective film of the present invention is 30% or more. If the porosity is less than 30%, it is difficult to sufficiently obtain the effects of the present invention. Moreover, a preferable porosity is 50% to 95%, and when the more severe durability test is performed in this range, a particularly preferable effect is exhibited.

  The void-retaining layer of the present invention means that the layer has an air phase in part or all, and the method for forming the air phase is not particularly limited, for example, , A method of forming a layer having a fine concavo-convex shape on a film substrate, and imparting an air phase to the indented portion between the convex portions, a method of forming a microvoid in the layer and imparting an air phase, And a method of adding an air phase by blending organic particles and inorganic particles.

  In addition, the porosity is obtained by cutting out a cross section of the first protective film using a microtome, observing the layer having the void of the first protective film with an electron microscope (transmission electron microscope, scanning electron microscope), and observing the cross section. It can be calculated from the ratio of the void area between the particles in the portion, or / and the ratio of the area of the hollow or bubble portion of the particle and the film thickness area, and the ratio of the recessed area and the film thickness area of the layer having voids.

<< first protective film >>
Hereinafter, the first protective film is also referred to as a film having a void retaining layer. First, the void retaining layer that is one of the features of the present invention will be described.

<Void retention layer>
The void retaining layer in the present invention forms a layer lower than the refractive index of the film substrate by having voids (air phase) in the layer, the refractive index is 23 ° C., the wavelength is measured at 550 nm, and the refractive index is 1. It is preferably in the range of 30 to 1.45.

  The film thickness of the void retaining layer is not particularly limited, but is preferably 5 nm to 0.5 μm, more preferably 10 nm to 0.3 μm, and 30 nm to 0.2 μm. Is most preferred.

  Hereinafter, the formation of voids will be specifically described.

  For example, the following method can be used to form the void.

  (1) The void retaining layer has a fine concavo-convex structure, the fine concavo-convex structure has a size equal to or smaller than the visible light wavelength, and the outer peripheral surface of the fine concavo-convex structure has an inclination from the top to the bottom. The method of forming a space | gap by having an air area | region (air phase) in the recessed part between convex parts by designing so that it may consist of a shape or an elliptic frustum shape.

  (2) A method of forming voids by forming microvoids in the void holding layer.

  (3) A method of forming voids by blending organic particles or inorganic particles containing hollow or bubbles in the void holding layer.

  Hereinafter, description will be made sequentially.

[Formation of fine uneven structure]
Voids can be formed in the gap holding layer according to the principles and methods described in JP-A Nos. 2004-205990, 2008-158013, and 2008-176076.

  FIG. 1 is a perspective view schematically showing an example of a fine concavo-convex structure formed according to the present invention. The fine concavo-convex structure formed by the present invention is preferably a structure having a very fine concavo-convex pattern in which the period Pmax at the apex of the fine concavo-convex is 380 nm or less which is the minimum wavelength λmin of the visible light wavelength band. .

  By providing such a fine concavo-convex structure on the surface of an antireflection article, it is possible to change a sudden and discontinuous refractive index change at the boundary with the air phase into a continuous and gradually changing refractive index change. Thus, light reflection on the surface of the article is reduced.

  As shown in FIG. 1, the fine concavo-convex structure 1 has a fine concavo-convex structure if Pmax is 380 nm or less, which is the minimum wavelength λmin of the visible light wavelength band, where Pmax is the period of the most convex portion 1t. Even if the refractive index of the medium (support and air) has a spatial distribution, the light reaching the surface on which the body is formed does not directly affect the light, but acts as an average. Therefore, the distribution changes continuously as the light advances the averaged refractive index (effective refractive index), and the reflection of light can be reduced.

  Strictly speaking, the wavelength of light in the object is λ / n where λ is the wavelength in vacuum and n is the refractive index of the object, and is generally somewhat smaller than λ. Become. However, since the refractive index when the object is air is n≈1, in the present invention, it is considered that λ / n≈λ.

  When it is assumed that the fine concavo-convex structure is cut by a plane (XY plane) orthogonal to the concavo-convex direction, the cross-sectional area occupancy of the material portion of the fine concavo-convex structure in the cross section is the most convex (top) The shape that gradually increases from the top to the most concave part (valley bottom), that is, the slope shape in which at least part of the side surface of the unevenness extends toward the bottom of the valley, or from the most convex part (top) to the most concave part (valley bottom) The shape that gradually decreases, that is, the slope shape in which at least part of the side surface of the unevenness narrows toward the bottom of the valley may be used, but the outer peripheral surface of the fine uneven structure has an inclination from the top to the bottom. The cone shape is preferable because it is easy to mold, and the refractive index in the thickness direction is continuously changed, and the effect of reducing the reflectance is easily obtained.

  Examples of the pyramid shape include a quadrilateral guess such as a square guess and a triangular guess, an elliptical cone shape or an elliptical truncated cone shape, and particularly preferably an elliptical cone shape or an elliptical truncated cone shape. For example, (A), (C), (E), and (F) in FIG. 2 may be used, in which the cross-sectional area occupation ratio of the material portion converges to 0 at the most convex portion and converges to 1 at the most concave portion. . Moreover, it is preferable that it is a fine concavo-convex structure which has the shape of FIGS. 9-11 and FIG. 22 of Unexamined-Japanese-Patent No. 2008-176076.

  The fine concavo-convex structure is said to have higher antireflection performance as the height of the concavo-convex is higher, and is preferably the same as or higher than the wavelength of the irradiation light. Therefore, in order to form a narrow and / or deep fine concavo-convex structure, the reproducibility of the period and height is required.

  In order to form a fine concavo-convex structure with good reproducibility, for example, by providing a concavo-convex structure forming layer made of a solid curable resin composition on a film substrate and pressing the stamper to perform embossing, An uneven structure can be formed.

  When the film substrate is in the form of a continuous film, it is wound into a roll stock form, stored and moved as necessary, then fed out of the film substrate, provided with a concavo-convex structure forming layer, and then supplied to the embossing process However, it can be done by embossing continuously, so it is very suitable for mass production.

  Examples of the film base used include acrylic resins such as poly (meth) methyl acrylate, poly (meth) ethyl acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer, polyethylene, and polypropylene. , Polymethylpentene, cyclic olefin polymers (typically norbornene resins, etc., for example, product name “ZEONOR” manufactured by ZEON CORPORATION, “ARTON” manufactured by JSR Corporation, etc.) Polyolefin resins, polycarbonate resins, thermoplastic polyester resins such as polyethylene terephthalate, polyethylene naphthalate, etc., polyamide resins, polyimide resins, polystyrene, acrylonitrile-styrene copolymers, polyether sulfone, polysulfone, triacetyl cellulose and other cellulose resins Examples thereof include polyvinyl acetate, ethylene-vinyl acetate copolymer, vinyl chloride, polyvinylidene chloride, polyetheretherketone, thermoplastic resins such as polyurethane, and glass (including ceramics). Is preferable because it is excellent in transparency, optical isotropy, and processability such as saponification.

  The curable resin composition needs to be hardened in order to fix a fine uneven structure formed by embossing and to obtain sufficient film properties such as strength. As reaction for exhibiting sclerosis | hardenability, photocurability, thermosetting, etc. are mentioned, for example. The photo-curable resin composition is preferable because it can be cured at a temperature lower than the embossing process temperature and hardly causes pattern collapse in the curing step.

  The curable resin composition is prepared by blending a binder polymer with a component that causes, accelerates, or regulates a curing reaction such as photo-curing property or thermosetting property and other components as necessary.

  As the binder polymer, either one having curable property itself or one having no curable property may be used, or two or more binder polymers may be used in combination. When the binder polymer does not have curability, curability can be imparted to the resin composition by using at least one monomer or oligomer having curability.

  The binder polymer has a film-forming property that can be a film having a sufficient thickness to shape a fine concavo-convex structure when coated on a support such as a film substrate, and is also suitable for optical articles after curing. Depending on the application, it can form surface structures with fine irregularities that satisfy general properties such as transparency, strength, scratch resistance, heat resistance, water resistance, chemical resistance, adhesion to substrates, and flexibility. Use polymer.

  For example, acrylic resin, polyester, epoxy resin, polyolefin, styrene resin, polyamide, polyimide, polyamideimide, polyurethane, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polycarbonate, melamine resin, urea resin, alkyd resin, phenol resin, cellulose resin , Diallyl phthalate resin, silicone resin, polyarylate resin, polyacetal resin, styrene-isoprene rubber, and the like, but are not limited thereto.

  Among these, the void retaining layer of the present invention preferably contains at least a cationic polymerization compound and a cationic polymerization initiator described later.

  Moreover, it can prepare by mix | blending photocurable components, such as another photoinitiator and a polymerization inhibitor, and also mix | blending other components, such as a mold release agent and an organometallic coupling agent.

  The photopolymerization initiator is preferably blended at a ratio of 0.5 to 10% by mass with respect to the total solid content of the photocurable resin composition. A photoinitiator may be used individually by 1 type and may be used in combination of 2 or more type.

  By adding a mold release agent to the curable resin composition, it is possible to prevent the resin from being removed when the stamper pressed against the layer of the curable resin composition is removed, and to use the stamper continuously for a long period of time (repetitive embossing property). ) Will be able to. As the release agent, conventionally known release agents such as polyethylene wax, amide wax, solid wax such as Teflon (registered trademark) powder, fluorine-based, phosphate ester-based surfactant, silicone, etc. can be used. It is. Particularly preferred are silicone release agents, such as polysiloxanes, modified silicone oils, polysiloxanes containing trimethylsiloxysilicic acid, and silicone acrylic resins.

  An organic metal coupling agent may be added to the curable resin composition in order to improve the heat resistance, strength, or adhesion of the fine concavo-convex structure to the metal deposition layer. In addition, the organometallic coupling agent is effective because it has an effect of promoting the thermosetting reaction. As the organometallic coupling agent, for example, various coupling agents such as a silane coupling agent, a titanium coupling agent, a zirconium coupling agent, an aluminum coupling agent, and a tin coupling agent can be used.

The curable resin composition preferably contains organic particles and inorganic particles for the purpose of adjusting transparency, slipperiness and refractive index. Particularly preferred is colloidal silica (SiO ₂ ) having a particle size on the order of submicrons.

  The curable resin composition is usually prepared in the state of a coating solution using a diluting solvent, and is used for forming an uneven pattern forming layer. Each material as described above is acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, benzene, toluene, xylene, chlorobenzene, tetrahydrofuran, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, ethyl acetate, 1,4- A coating solution can be prepared by dissolving and dispersing in dioxane, 1,2-dichloroethane, dichloromethane, chloroform, methanol, ethanol, isopropanol, or a mixed solvent thereof. The coating solution is usually adjusted so that the solid content concentration is about 10 to 50% by mass.

  A concavo-convex structure receptor is produced by applying the curable resin composition to the surface of a support such as a film substrate and drying it as necessary to form a fine concavo-convex structure forming layer.

  Since the fine concavo-convex structure has a very fine structure having a periodic structure equal to or less than the wavelength of light, the thickness of the fine concavo-convex structure forming layer is usually about 0.3 to 5 μm, and 0.5 It is preferable to be in the range of ˜3 μm.

  As an example of producing a continuous film-like uneven structure receptor, first, a film base material (support) made of continuous plastic such as triacetylcellulose is fed out from a roll stock. A fine concavo-convex structure forming material (for example, a curable resin composition) made of a photocurable resin composition is applied onto the drawn film base using a gravure coater, and then the organic contained in the composition A concavo-convex structure receptor is prepared by forming the fine concavo-convex structure-forming layer by introducing it into a heating furnace set at a temperature at which the solvent scatters, for example, 100 to 165 ° C., for about 0.1 to 1 minute and drying. As a coating machine other than the gravure coater, for example, a roll coater, a curtain coater, a flow coater, a lip coater, a doctor blade coater and the like can be used.

  As the stamper, it is preferable to use a replication mold produced by performing a replication process by mold taking / reversing once or twice from the original mold, without using the original mold formed with the fine irregular shape first. In other words, first, once a prototype (this is also referred to as a master plate or a mother plate) is produced, a duplication operation for producing a duplicate mold from this master mold is performed once or twice, and the resulting duplicate mold is obtained. Is used as a stamper. Such a replica-type stamper can be easily re-created from the original model, so that it is excellent in industrial productivity, cost, etc. For example, it can be easily replaced when the stamper is damaged.

  The original mold for the shaping mold is not particularly limited as long as the necessary fine irregularities are formed, and the production method is appropriately determined in consideration of productivity, cost, etc. Use something. Prototype production is a process of first forming a concavo-convex shape for shaping a fine concavo-convex shape, which is a so-called microfabrication technique in the semiconductor field or the like, that is, a so-called pattern formation using light (including an electron beam). An exposure method can be used. However, in the case of a semiconductor, the side surface of the concavo-convex shape may be a vertical surface, and it is not particularly necessary to have a slope as in the present invention. Therefore, in the present invention, the slope is such that the mountain side is sharper than the valley side. Are arranged so that can be formed.

As a fine processing technology corresponding to the exposure method, for example, an electron beam drawing method can be used. An example of a manufacturing method using this method is that after a chromium film (110 nm thickness) is formed on quartz glass, a resist is applied to a thickness of 400 nm by spin coating, and then a mesh having a period of 300 nm is formed by an electron beam drawing apparatus. The image is drawn using the drawn image data, and development processing is performed using the developer. The drawing condition is 5 to 8 μC / cm ² . Thereby, an area corresponding to the hatched area of the drawing data is opened by development. Next, the metal chromium film exposed from the opening of the resist is dry-etched using a chlorine-based gas to open it. A dry etching apparatus “VERSALOCK 7000” manufactured by Unaxis can be used for dry etching of the chromium metal film. Next, by performing dry etching of quartz glass using a resist and a metal chromium film as an etching resistant layer and using a fluorine-based gas, a desired fine uneven shape can be obtained. In addition, “MEPS-6025D” manufactured by Nippon Vacuum Co., Ltd. can be used for dry etching of the processing material (quartz glass).

  In forming a pattern on the resist film, a laser drawing method can be used as another exposure method of the electron beam drawing method. In the laser drawing method, a laser interference method used for producing a hologram, a diffraction grating, or the like can be used. In the case of a diffraction grating, it is a one-dimensional arrangement, but a two-dimensional arrangement is also possible if multiple exposures are performed at different angles.

  If an example of the preparation method by this method is shown, after spin-coating a resist (a photoresist “S1805” manufactured by Shipley Co., Ltd.) on the glass surface, two-way exposure is performed twice at different angles. The exposure amount per time is 80 to 200 mJ. If this is developed with a developer diluted to 20 to 505% (for example, “Developer CONC” manufactured by Shipley Co., Ltd.), a desired fine uneven shape can be obtained.

  In the laser interference method, the fine irregularities obtained are usually regularly arranged. On the other hand, in the electron beam drawing method, predetermined drawing pattern information is stored as digital data in a storage device in advance. The drawing pattern information modulates ON, OFF, or intensity of the scanning electron beam. Therefore, in addition to the regular arrangement, irregular arrangement is also possible. Further, since the laser drawing method and the electron beam drawing method each have advantages and disadvantages, appropriate methods and conditions are selected in consideration of design specifications, purpose, productivity, and the like.

  As a method for producing a replica mold used as a stamper from the above-mentioned prototype, there are known methods such as a known electroforming method and a 2P method.

  The fine concavo-convex structure is produced by forming a fine concavo-convex structure by pressing a stamper on the surface of the concavo-convex structure-forming layer of the concavo-convex structure receiver, and then exposing the concavo-convex structure-forming layer by an appropriate method such as exposure or heating. By curing, a fine concavo-convex structure can be produced.

  When the concavo-convex structure receptor passes between the embossing rollers, the portion of the concavo-convex structure forming layer where the fine concavo-convex structure is shaped is peeled off from the stamper, and a curing process is performed. When the concavo-convex structure forming layer is made of a photocurable resin, it is cured by light irradiation, and when the concavo-convex structure forming layer is made of a thermosetting resin, it is cured by heating.

  Examples of the light used for curing include high energy ionizing radiation and ultraviolet rays. As the high-energy ionizing radiation source, for example, an electron beam accelerated by an accelerator such as a cockcroft accelerator, a handagraaf accelerator, a linear accelerator, a betatron, or a cyclotron is industrially most conveniently and economically used. However, radiation such as γ rays, X rays, α rays, neutron rays, proton rays emitted from radioisotopes or nuclear reactors can also be used. Examples of the ultraviolet ray source include an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a carbon arc lamp, and a solar lamp.

[Formation of microvoids]
As the void retaining layer, it is also preferable to use a layer having voids formed as microvoids between or within the fine particles using inorganic or organic fine particles. The average particle diameter of the fine particles is preferably 0.5 to 200 nm, more preferably 1 to 100 nm, still more preferably 3 to 70 nm, and most preferably in the range of 5 to 40 nm. The particle diameter of the fine particles is preferably as uniform (monodispersed) as possible.

The inorganic fine particles are preferably amorphous. The inorganic fine particles are preferably made of a metal oxide, nitride, sulfide or halide, more preferably a metal oxide or a metal halide, and most preferably a metal oxide or a metal fluoride. . As metal atoms, Na, K, Mg, Ca, Ba, Al, Zn, Fe, Cu, Ti, Sn, In, W, Y, Sb, Mn, Ga, V, Nb, Ta, Ag, Si, B Bi, Mo, Ce, Cd, Be, Pb and Ni are preferable, and Mg, Ca, B and Si are more preferable. An inorganic compound containing two kinds of metals may be used. Specific examples of preferable inorganic compounds are SiO ₂ and MgF ₂ , and SiO ₂ is particularly preferable.

The particles having microvoids in the inorganic fine particles can be formed, for example, by crosslinking silica molecules forming the particles. Crosslinking silica molecules reduces the volume and makes the particles porous. (Porous) inorganic fine particles having microvoids are prepared by a sol-gel method (described in JP-A-53-112732 and JP-B-57-9051) or a precipitation method (described in APPLIED OPTICS, 27, 3356 (1988)). Can be directly synthesized as a dispersion. Further, the powder obtained by the drying / precipitation method can be mechanically pulverized to obtain a dispersion. Commercially available porous inorganic fine particles (for example, SiO ₂ sol) may be used.

  These inorganic fine particles are preferably used in a state of being dispersed in an appropriate medium in order to form a void retaining layer. As the dispersion medium, water, alcohol (for example, methanol, ethanol, isopropyl alcohol) and ketone (for example, methyl ethyl ketone, methyl isobutyl ketone) are preferable.

  The organic fine particles are also preferably amorphous. The organic fine particles are preferably polymer fine particles synthesized by polymerization reaction of monomers (for example, emulsion polymerization method). The organic fine particle polymer preferably contains a fluorine atom. The proportion of fluorine atoms in the polymer is preferably 35 to 80% by mass, and more preferably 45 to 75% by mass. It is also preferable to form microvoids in the organic fine particles by, for example, cross-linking the polymer forming the particles and reducing the volume. In order to crosslink the polymer forming the particles, it is preferable to use 20 mol% or more of the monomer for synthesizing the polymer as a polyfunctional monomer. The ratio of the polyfunctional monomer is more preferably 30 to 80 mol%, and most preferably 35 to 50 mol%. Examples of the monomer used for the synthesis of the organic fine particles include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene) as examples of monomers containing fluorine atoms used to synthesize fluorine-containing polymers. , Perfluoro-2,2-dimethyl-1,3-dioxole), fluorinated alkyl esters of acrylic acid or methacrylic acid, and fluorinated vinyl ethers. A copolymer of a monomer containing a fluorine atom and a monomer not containing a fluorine atom may be used. Examples of monomers that do not contain fluorine atoms include olefins (eg, ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride), acrylic esters (eg, methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate). , Methacrylates (eg, methyl methacrylate, ethyl methacrylate, butyl methacrylate), styrenes (eg, styrene, vinyl toluene, α-methyl styrene), vinyl ethers (eg, methyl vinyl ether), vinyl esters ( Examples thereof include vinyl acetate and vinyl propionate), acrylamides (for example, N-tert-butylacrylamide, N-cyclohexylacrylamide), methacrylamides and acrylonitriles. Examples of polyfunctional monomers include dienes (eg, butadiene, pentadiene), esters of polyhydric alcohols and acrylic acid (eg, ethylene glycol diacrylate, 1,4-cyclohexane diacrylate, dipentaerythritol hexaacrylate), Esters of polyhydric alcohol and methacrylic acid (for example, ethylene glycol dimethacrylate, 1,2,4-cyclohexanetetramethacrylate, pentaerythritol tetramethacrylate), divinyl compounds (for example, divinylcyclohexane, 1,4-divinylbenzene), divinyl Examples include sulfones, bisacrylamides (eg, methylenebisacrylamide) and bismethacrylamides.

  Microvoids between particles can be formed by stacking at least two fine particles. When spherical particles having the same particle diameter (completely monodispersed) are closely packed, microvoids between particles with a porosity of 26% by volume are formed. When spherical fine particles having the same particle diameter are simply filled with cubic particles, microvoids between fine particles having a porosity of 48% by volume are formed. In the actual void retaining layer, the particle size distribution of the fine particles and the microvoids in the particles exist, so that the porosity varies considerably from the above theoretical value. When the porosity is increased, the refractive index of the void retaining layer is lowered. When microvoids are formed by stacking fine particles, the size of the microvoids can be adjusted to an appropriate value (does not scatter light and cause no problem with the strength of the void retaining layer) by adjusting the particle size of the fine particles. it can. Furthermore, by making the particle diameters of the fine particles uniform, it is possible to obtain an optically uniform void holding layer in which the size of the microvoids between the particles is uniform. Thereby, although the void retaining layer is microscopically a microvoided porous film, it can be optically or macroscopically uniform. The interparticle microvoids are preferably closed in the void retaining layer by the fine particles and the polymer. That is, the voids are preferably dispersed in the layer.

  Closed voids also have the advantage of less light scattering on the void retention layer surface compared to the openings opened on the void retention layer surface.

  By forming the microvoids, the macroscopic refractive index of the void retaining layer becomes lower than the sum of the refractive indexes of the components constituting the void retaining layer. The refractive index of the layer is the sum of the refractive indices per volume of the layer components. The refractive index of the constituent component of the void retaining layer such as fine particles or polymer is a value larger than 1, whereas the refractive index of air is 1.00. Therefore, by forming microvoids, a void retaining layer having a very low refractive index can be obtained.

[Composition of particles having hollow or bubbles]
It is also preferable that the void retaining layer of the present invention contains particles having hollow or bubbles. In particular, it is preferable to contain at least one kind of particles having an outer shell layer and porous or hollow inside. Among these, particles having the outer shell layer and porous or hollow inside are hollow silica-based fine particles. preferable.

(Hollow silica fine particles)
The hollow silica-based fine particles are (I) a composite particle comprising porous particles and a coating layer provided on the surface of the porous particles, or (II) having a cavity inside, and the content is a solvent, gas or porous It is a hollow particle filled with a porous material. Note that the void retaining layer only needs to contain either (I) composite particles or (II) hollow particles, or both.

  Note that the cavity particles are particles having a cavity inside, and the cavity is covered with a coating layer (also referred to as a particle wall). The cavity is filled with contents such as a solvent, a gas, or a porous material used at the time of preparation. It is desirable that the average particle size of such hollow fine particles is in the range of 5 to 300 nm, preferably 10 to 200 nm. The average particle size of the hollow fine particles used is desirably 3/2 to 1/10, preferably 2/3 to 1/10, of the average film thickness of the void-retaining layer to be formed. These hollow fine particles are preferably used in a state of being dispersed in an appropriate medium in order to form a void retaining layer. As the dispersion medium, water, alcohol (for example, methanol, ethanol, isopropyl alcohol) and ketone (for example, methyl ethyl ketone, methyl isobutyl ketone), ketone alcohol (for example, diacetone alcohol), or a mixed solvent containing these is preferable.

  The thickness of the coating layer of the composite particles or the thickness of the particle walls of the hollow particles is desirably in the range of 1 to 20 nm, preferably 2 to 15 nm. In the case of composite particles, if the thickness of the coating layer is less than 1 nm, the particles may not be completely covered, and it is easy to use a silicate monomer or oligomer having a low polymerization degree, which is a coating liquid component described later. In some cases, the refractive index of the particles is increased by entering the voids inside the composite particles, and the effect of low refractive index may not be sufficiently obtained. When the thickness of the coating layer exceeds 20 nm, the silicic acid monomer and oligomer do not enter the inside, but the porosity (pore volume) of the composite particles is lowered and the effect of low refractive index is sufficiently obtained. It may not be possible. In the case of hollow particles, if the particle wall thickness is less than 1 nm, the particle shape may not be maintained, and even if the thickness exceeds 20 nm, the effect of low refractive index may not be sufficiently exhibited. .

The coating layer of the composite particles or the particle wall of the hollow particles is preferably composed mainly of silica. Moreover, components other than silica may be contained, and specifically, Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , P ₂ O ₃ , Sb ₂ O _3. , MoO ₃ , ZnO ₂ , WO _{3 and the} like. Examples of the porous particles constituting the composite particles include those made of silica, those made of silica and an inorganic compound other than silica, and those made of CaF ₂ , NaF, NaAlF ₆ , MgF, and the like. Among these, porous particles made of a composite oxide of silica and an inorganic compound other than silica are particularly preferable. Examples of inorganic compounds other than silica include Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , P ₂ O ₃ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ and WO _3. 1 type or 2 types or more can be mentioned. In such porous particles, the molar ratio MO _X / SiO ₂ when the silica is expressed by SiO ₂ and the inorganic compound other than silica is expressed in terms of oxide (MO _X ) is 0.0001 to 1.0, Preferably it is in the range of 0.001 to 0.3. It is difficult to obtain a porous particle having a molar ratio MO _X / SiO ₂ of less than 0.0001. Even if it is obtained, a pore volume is small and particles having a low refractive index cannot be obtained. In addition, when the molar ratio MO _X / SiO _{2 of} the porous particles exceeds 1.0, the ratio of silica decreases, so that the pore volume increases and it is difficult to obtain a material having a lower refractive index. is there.

  The pore volume of such porous particles is desirably in the range of 0.1 to 1.5 ml / g, preferably 0.2 to 1.5 ml / g. If the pore volume is less than 0.1 ml / g, particles having a sufficiently reduced refractive index cannot be obtained. If the pore volume exceeds 1.5 ml / g, the strength of the fine particles is lowered, and the strength of the resulting coating may be lowered. is there.

  In addition, the pore volume of such porous particles can be determined by a mercury intrusion method. Examples of the contents of the hollow particles include a solvent, a gas, and a porous substance used at the time of preparing the particles. The solvent may contain an unreacted particle precursor used when preparing the hollow particles, the catalyst used, and the like. Moreover, what consists of the compound illustrated by the said porous particle as a porous substance is mentioned. These contents may be composed of a single component or may be a mixture of a plurality of components.

  As a method for producing such hollow fine particles, for example, the method for preparing composite oxide colloidal particles disclosed in paragraphs [0010] to [0033] of JP-A-7-133105 is suitably employed. Specifically, when the composite particles are composed of silica and an inorganic compound other than silica, hollow fine particles are produced from the following first to third steps.

First Step: Preparation of Porous Particle Precursor In the first step, an alkali aqueous solution of a silica raw material and an inorganic compound raw material other than silica is separately prepared in advance, or a silica raw material and an inorganic compound raw material other than silica are prepared in advance. A mixed aqueous solution is prepared, and this aqueous solution is gradually added to an aqueous alkaline solution having a pH of 10 or more while stirring according to the composite ratio of the target composite oxide to prepare a porous particle precursor.

  As the silica raw material, alkali metal, ammonium or organic base silicate is used. Sodium silicate (water glass) or potassium silicate is used as the alkali metal silicate. Examples of the organic base include quaternary ammonium salts such as tetraethylammonium salt, and amines such as monoethanolamine, diethanolamine, and triethanolamine. The ammonium silicate or the organic base silicate includes an alkaline solution obtained by adding ammonia, a quaternary ammonium hydroxide, an amine compound or the like to a silicic acid solution.

  In addition, alkali-soluble inorganic compounds are used as raw materials for inorganic compounds other than silica. Specifically, an oxo acid of an element selected from Al, B, Ti, Zr, Sn, Ce, P, Sb, Mo, Zn, W, etc., an alkali metal salt or alkaline earth metal salt of the oxo acid, ammonium And salts and quaternary ammonium salts. More specifically, sodium aluminate, sodium tetraborate, zirconyl ammonium carbonate, potassium antimonate, potassium stannate, sodium aluminosilicate, sodium molybdate, cerium ammonium nitrate, and sodium phosphate are suitable.

Although the pH value of the mixed aqueous solution changes simultaneously with the addition of these aqueous solutions, an operation for controlling the pH value within a predetermined range is not particularly required. The aqueous solution finally has a pH value determined by the type of inorganic oxide and the mixing ratio thereof. There is no restriction | limiting in particular in the addition rate of the aqueous solution at this time. Further, in the production of composite oxide particles, a dispersion of seed particles can be used as a starting material. The seed particles are not particularly limited, but inorganic oxides such as SiO ₂ , Al ₂ O ₃ , TiO ₂ or ZrO ₂ or fine particles of these composite oxides are used. Usually, these sols are used. Can do. Furthermore, the porous particle precursor dispersion obtained by the above production method may be used as a seed particle dispersion. When using a seed particle dispersion, the pH of the seed particle dispersion is adjusted to 10 or higher, and then an aqueous solution of the compound is added to the above-mentioned alkaline aqueous solution while stirring. Also in this case, it is not always necessary to control the pH of the dispersion. When seed particles are used in this way, it is easy to control the particle size of the porous particles to be prepared, and particles with uniform particle sizes can be obtained.

  The silica raw material and the inorganic compound raw material described above have high solubility on the alkali side. However, when both are mixed in this highly soluble pH region, the solubility of oxo acid ions such as silicate ions and aluminate ions decreases, and these composites precipitate and grow into fine particles, or seed particles. It grows on the top and particle growth occurs. Therefore, it is not always necessary to perform pH control as in the conventional method for precipitation and growth of fine particles.

The composite ratio of silica and an inorganic compound other than silica in the first step is that the inorganic compound relative to silica is converted to an oxide (MO _X ), and the molar ratio of MO _X / SiO ₂ is 0.05 to 2.0, Preferably it is in the range of 0.2-2.0. Within this range, the pore volume of the porous particles increases as the proportion of silica decreases. However, even when the molar ratio exceeds 2.0, the pore volume of the porous particles hardly increases. On the other hand, when the molar ratio is less than 0.05, the pore volume becomes small. When preparing the hollow particles, the molar ratio of MO _X / SiO ₂ is preferably in the range of 0.25 to 2.0.

Second step: Removal of inorganic compound other than silica from porous particles In the second step, inorganic compounds other than silica (elements other than silicon and oxygen) are obtained from the porous particle precursor obtained in the first step. At least a portion is selectively removed. As a specific removal method, the inorganic compound in the porous particle precursor is dissolved and removed using a mineral acid or an organic acid, or is contacted with a cation exchange resin for ion exchange removal.

  The porous particle precursor obtained in the first step is a particle having a network structure in which silicon and an inorganic compound constituent element are bonded through oxygen. By removing the inorganic compound (elements other than silicon and oxygen) from the porous particle precursor in this way, porous particles having a larger porosity and a larger pore volume can be obtained. Further, if the amount of removing the inorganic oxide (elements other than silicon and oxygen) from the porous particle precursor is increased, the hollow particles can be prepared.

  In addition, prior to removing inorganic compounds other than silica from the porous particle precursor, fluorine-substituted, obtained by dealkalizing an alkali metal salt of silica into the porous particle precursor dispersion obtained in the first step. It is preferable to add a silicic acid solution containing an alkyl group-containing silane compound or a hydrolyzable organosilicon compound to form a silica protective film. The thickness of the silica protective film may be 0.5 to 15 nm. Even if the silica protective film is formed, the protective film in this step is porous and thin, so that it is possible to remove inorganic compounds other than silica described above from the porous particle precursor.

  By forming such a silica protective film, inorganic compounds other than silica described above can be removed from the porous particle precursor while maintaining the particle shape. Further, when forming the silica coating layer described later, the pores of the porous particles are not blocked by the coating layer, and therefore the silica coating layer described later is formed without reducing the pore volume. Can do. Note that when the amount of the inorganic compound to be removed is small, the particles are not broken, and thus it is not always necessary to form a protective film.

  When preparing hollow particles, it is desirable to form this silica protective film. When preparing the hollow particles, the inorganic compound is removed to obtain a hollow particle precursor composed of a silica protective film, a solvent in the silica protective film, and an undissolved porous solid content. When a coating layer to be described later is formed on the precursor, the formed coating layer becomes a particle wall to form hollow particles.

The amount of the silica source added for forming the silica protective film is preferably small as long as the particle shape can be maintained. If the amount of the silica source is too large, the silica protective film becomes too thick, and it may be difficult to remove inorganic compounds other than silica from the porous particle precursor. The hydrolyzable organic silicon compound used for the silica protective film formed of the general formula _{R n Si (OR ') 4} -n [R, R': an alkyl group, an aryl group, a vinyl group, such as acrylic group An alkoxysilane represented by a hydrocarbon group, n = 0, 1, 2, or 3] can be used. In particular, tetraalkoxysilanes such as fluorine-substituted tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane are preferably used.

  As an addition method, a solution obtained by adding a small amount of alkali or acid as a catalyst to a mixed solution of these alkoxysilane, pure water, and alcohol is added to the dispersion of the porous particles, and the alkoxysilane is hydrolyzed. The produced silicic acid polymer is deposited on the surface of the inorganic oxide particles. At this time, alkoxysilane, alcohol, and catalyst may be simultaneously added to the dispersion. As the alkali catalyst, ammonia, an alkali metal hydroxide, or an amine can be used. As the acid catalyst, various inorganic acids and organic acids can be used.

  When the dispersion medium of the porous particle precursor is water alone or when the ratio of water to the organic solvent is high, a silica protective film can be formed using a silicic acid solution. When a silicic acid solution is used, a predetermined amount of the silicic acid solution is added to the dispersion, and at the same time an alkali is added to deposit the silicic acid solution on the surface of the porous particles. In addition, you may produce a silica protective film together using a silicic acid liquid and the said alkoxysilane.

Third step: Formation of silica coating layer In the third step, the porous particle dispersion prepared in the second step (in the case of hollow particles, the hollow particle precursor dispersion) contains a fluorine-substituted alkyl group-containing silane compound. By adding a hydrolyzable organosilicon compound or silicic acid solution, the surface of the particles is coated with a polymer such as a hydrolyzable organosilicon compound or silicic acid solution to form a silica coating layer.

The hydrolyzable organic silicon compound used for the silica coating layer formed, the above-mentioned such general formula _{R n Si (OR ') 4} -n [R, R': an alkyl group, an aryl group, a vinyl group, An alkoxysilane represented by a hydrocarbon group such as an acryl group, n = 0, 1, 2, or 3] can be used. In particular, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane are preferably used.

  As an addition method, a solution obtained by adding a small amount of alkali or acid as a catalyst to a mixed solution of these alkoxysilane, pure water, and alcohol is used as a dispersion of the porous particles (in the case of hollow particles, a hollow particle precursor). In addition, the silicic acid polymer produced by hydrolyzing alkoxysilane is deposited on the surface of the porous particles (in the case of hollow particles, hollow particle precursors). At this time, alkoxysilane, alcohol, and catalyst may be simultaneously added to the dispersion. As the alkali catalyst, ammonia, an alkali metal hydroxide, or an amine can be used. As the acid catalyst, various inorganic acids and organic acids can be used.

  When the dispersion medium of porous particles (in the case of hollow particles, the hollow particle precursor) is water alone or a mixed solvent with an organic solvent and the mixed solvent has a high ratio of water to the organic solvent, a silicate solution You may form a coating layer using. The silicic acid solution is an aqueous solution of a low silicic acid polymer obtained by dealkalizing an aqueous solution of an alkali metal silicate such as water glass by ion exchange treatment.

  The silicic acid solution is added to the dispersion of porous particles (in the case of hollow particles, hollow particle precursors), and at the same time, alkali is added to make the low-silicic acid polymer into porous particles (in the case of hollow particles, hollow particle precursors). ) Deposit on the surface. In addition, you may use a silicic acid liquid for the coating layer formation in combination with the said alkoxysilane. The addition amount of the organosilicon compound or silicic acid solution used for forming the coating layer only needs to be sufficient to cover the surface of the colloidal particles, and the finally obtained silica coating layer has a thickness of 1 to 20 nm. In such an amount, it is added in a dispersion of porous particles (in the case of hollow particles, a hollow particle precursor). When the silica protective film is formed, the organosilicon compound or the silicate solution is added in such an amount that the total thickness of the silica protective film and the silica coating layer is in the range of 1 to 20 nm.

  Next, the dispersion liquid of the particles on which the coating layer is formed is heat-treated. By the heat treatment, in the case of porous particles, the silica coating layer covering the surface of the porous particles is densified, and a dispersion of composite particles in which the porous particles are coated with the silica coating layer is obtained. In the case of a hollow particle precursor, the formed coating layer is densified to form hollow particle walls, and a dispersion of hollow particles having cavities filled with a solvent, gas, or porous solid content is obtained.

  The heat treatment temperature at this time is not particularly limited as long as it can close the fine pores of the silica coating layer, and is preferably in the range of 80 to 300 ° C. When the heat treatment temperature is less than 80 ° C., the fine pores of the silica coating layer may not be completely closed and densified, and the treatment time may take a long time. Further, when the heat treatment temperature exceeds 300 ° C. for a long time, fine particles may be formed, and the effect of low refractive index may not be obtained.

  The refractive index of the inorganic fine particles thus obtained is as low as less than 1.42. Such inorganic fine particles are presumed to have a low refractive index because the porosity inside the porous particles is maintained or the inside is hollow. As the hollow silica-based fine particles, those commercially available from Catalyst Kasei Co., Ltd. can be preferably used.

  The content of the hollow silica-based fine particles having an outer shell layer and being porous or hollow in the void retaining layer is preferably 10 to 50% by mass. In order to obtain the effect of a low refractive index, the content is preferably 15% by mass or more. Most preferably, it is 20-50 mass%.

  As a method for adding to the void retaining layer, for example, a solution obtained by adding a small amount of alkali or acid as a catalyst to a mixed solution of tetraalkoxysilane, pure water, and alcohol is added to the dispersion of the hollow silica-based fine particles. Silicic acid polymer produced by hydrolyzing alkoxysilane is deposited on the surface of hollow silica fine particles. At this time, tetraalkoxysilane, alcohol, and catalyst may be simultaneously added to the dispersion. As the alkali catalyst, ammonia, an alkali metal hydroxide, or an amine can be used. As the acid catalyst, various inorganic acids and organic acids can be used. Silica-based fine particles may be those produced by the production method described in the pamphlet of WO2007 / 099814.

(Cationically polymerizable compound)
The void retaining layer preferably contains a cationically polymerizable compound as a binder from the viewpoint of better achieving the object effect of the present invention. Any cationically polymerizable compound can be used as long as it undergoes cationic polymerization by irradiation with energy active rays or heat to form a resin. Specific examples include an epoxy group, a cyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro orthoester compound, and a vinyloxo group. Among them, a compound having a functional group such as an epoxy group or a vinyl ether group is preferably used in the present invention. Examples of the cationically polymerizable compound having an epoxy group or a vinyl ether group include phenyl glycidyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, vinylcyclohexene dioxide, limonene dioxide, 3,4-epoxycyclohexylmethyl-3 ′. , 4'-epoxycyclohexanecarboxylate, bis- (6-methyl-3,4-epoxycyclohexyl) adipate, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, 1 , 4-cyclohexanedimethanol divinyl ether and the like. Moreover, as an epoxy compound, a polymer compound can also be used, for example, it is compoundable by the method currently disclosed by Unexamined-Japanese-Patent No. 7-247313.

  Moreover, an oxetane compound can also be mentioned as a cationically polymerizable compound. As the oxetane compound, any compound having at least one oxetane ring in the molecule may be used, and various compounds can be used as such an oxetane compound. Preferred compounds include the following general formula (I), Compounds of general formula (II) and general formula (III).

(Wherein R ⁷ represents hydrogen, fluorine, alkyl group, fluoroalkyl group, allyl group, aryl group or furyl group, m represents an integer of 1 to 4, Z represents oxygen or sulfur, R ⁸ Represents a monovalent to tetravalent organic group depending on the value of m.)

(In the formula, R ⁹ and R ¹⁰ each independently represent hydrogen, fluorine, an alkyl group, a fluoroalkyl group, an allyl group, an aryl group, or a furyl group.)

(Wherein R ¹¹ represents hydrogen, fluorine, an alkyl group, a fluoroalkyl group, an allyl group, an aryl group or a furyl group, R ¹² represents hydrogen or an inert monovalent organic group, and R ¹³ represents water Represents a decomposable functional group, n represents an integer of 1 to 5, and p represents an integer of 0 to 2.)
In the above general formulas (I) to (III), when R ⁷ , R ⁹ , R ¹⁰ and R ¹¹ are alkyl groups, the carbon number thereof can be about 1 to 6, specifically, methyl, Examples include ethyl, propyl, butyl and the like. The fluoroalkyl group can also have about 1 to 6 carbon atoms. Furthermore, the aryl group is typically phenyl or naphthyl, which may be substituted with other groups.

In addition, the organic group represented by R ⁸ in the general formula (I) is not particularly limited. For example, when m is 1, an alkyl group, a phenyl group, or the like, and when m is 2, the number of carbon atoms is When m is 3 or 4, 1 to 12 linear or branched alkylene groups, linear or branched poly (alkyleneoxy) groups, and the like, a similar polyvalent functional group is exemplified.

The inactive monovalent organic group represented by R ¹² in the general formula (II) typically includes an alkyl group having 1 to 4 carbon atoms, and is hydrolyzable represented by R ^13. Examples of the functional group include an alkoxy group having 1 to 5 carbon atoms including methoxy and ethoxy, and a halogen atom such as a chlorine atom and a bromine atom.

  Furthermore, if necessary, a (co) polymer containing a monomer having a hydrogen bond-forming group and a reactive polymer having an oxetanyl group in the main chain or side chain and having a number average molecular weight of 20,000 or more can also be used.

  Moreover, you may use the fluorine-containing vinyl ether compound as shown by the following general formula.

_{CH 2 = CH-O- (CH} 2) a-O- (CH 2) b-Rf- (CH 2) b-O- (CH 2) a-O-CH = CH 2
(In the formula, Rf represents a fluorine-containing alkyl group, a represents an integer of 1 to 2, and b represents an integer of 0 to 3. Rf may be a linear or branched alkyl group.)
Specific compounds are as follows.

_{CH 2 = CH-O-CH} 2 -O- (CF 2) k-O-CH 2 -O-CH = CH 2
_{CH 2 = CH-O-CH} 2 -O-CH 2 - (CF 2) k-CH 2 -O-CH 2 -O-CH = CH 2
_{CH 2 = CH-O-CH} 2 -O- (CH 2) 2 - (CF 2) k- (CH 2) 2 -O-CH 2 -O-CH = CH 2
_{CH 2 = CH-O-CH} 2 -O- (CH 2) 3 - (CF 2) k- (CH 2) 3 -O-CH 2 -O-CH = CH 2
_{CH 2 = CH-O- (CH} 2) 2 -O- (CF 2) k-O- (CH 2) 2 -O-CH = CH 2
_{CH 2 = CH-O- (CH} 2) 2 -O-CH 2 - (CF 2) k-CH 2 -O- (CH 2) 2 -O-CH = CH 2
_{CH 2 = CH-O- (CH} 2) 2 -O- (CH 2) 2 - (CF 2) k- (CH 2) 2 -O- (CH 2) 2 -O-CH = CH 2
_{CH 2 = CH-O- (CH} 2) 2 -O- (CH 2) 3 - (CF 2) k- (CH 2) 3 -O- (CH 2) 2 -O-CH = CH 2
In the above, k is preferably an integer of 2 or more and 12 or less, and more preferably, k is 4 or more and 10 or less. The fluorine-containing vinyl ether compound can be produced by reacting a fluorine-containing dialcohol and a vinyl ether having a halogen group in the presence of an alkali catalyst. Moreover, you may contain a fluorine-containing epoxy compound, for example, the compound as described in General formula (1)-(4) of Unexamined-Japanese-Patent No. 11-309830 can be used. Specific examples include the following fluorine-containing epoxy compounds 1 to 4, but are not limited thereto.

  Fluorine-containing epoxy compound 1

  Fluorine-containing epoxy compound 2

  Fluorine-containing epoxy compound 3

  Fluorine-containing epoxy compound 4

  In addition, the compounds described in JP-A-2007-254650, paragraph numbers [116] to [126] can also be mentioned.

  The above-mentioned cationically polymerizable compound is preferably 15% by mass or more and less than 70% by mass in the solid content in the low refractive layer coating composition from the viewpoint of the stability of the low refractive layer coating composition.

(Cationic polymerization accelerator)
In addition, examples of the compound that accelerates the polymerization of the cationic polymerizable compound include known acids and photoacid generators. Examples of the photoacid generator include a cationic polymerization photoinitiator, a dye photodecoloring agent, a photochromic agent, a known compound used in a microresist, and a mixture thereof. Specific examples include onium compounds, organic halogen compounds, and disulfone compounds, and onium compounds are preferable. As the onium compound, diazonium salts, sulfonium salts, iodonium salts and the like represented by the following formulas are preferably used.

ArN ₂ ⁺ Z ⁻ ,
(R) ₃ S ⁺ Z ⁻ ,
(R) ₂ I ⁺ Z ⁻
In the formula, Ar represents an aryl group, R represents an aryl group or an alkyl group having 1 to 20 carbon atoms, and when R appears multiple times in one molecule, they may be the same or different, and Z ⁻ Represents a non-basic and non-nucleophilic anion.

In each of the above formulas, the aryl group represented by Ar or R is also typically phenyl or naphthyl, and these may be substituted with an appropriate group. Specific examples of the anion represented by Z ⁻ include tetrafluoroborate ion (BF ₄ ⁻ ), tetrakis (pentafluorophenyl) borate ion (B (C ₆ F ₅ ) ₄ ⁻ ), and hexafluorophosphate ion. (PF ₆ ⁻ ), hexafluoroarsenate ion (AsF ₆ ⁻ ), hexafluoroantimonate ion (SbF ₆ ⁻ ), hexachloroantimonate ion (SbCl ₆ ⁻ ), hydrogen sulfate ion (HSO ₄ ⁻ ), perchloric acid Ion (ClO ₄ ⁻ ) and the like.

  Examples of other onium compounds include ammonium salts, iminium salts, phosphonium salts, arsonium salts, selenonium salts, boron salts and the like. For example, as described in JP-A-2002-29162, paragraph numbers [0058] to [0059] Compounds and the like.

  Of these, diazonium salts, iodonium salts, sulfonium salts, and iminium salts are preferable from the viewpoint of the material stability of the compound.

  Specific examples of onium salts that can be suitably used include, for example, an amylated sulfonium salt described in paragraph No. [0035] of JP-A No. 9-268205, and paragraph Nos. Of JP-A No. 2000-71366. 0010]-[0011] diaryl iodonium salt or triarylsulfonium salt, thiobenzoic acid S-phenyl ester sulfonium salt described in JP-A-2001-288205, paragraph number [0017], JP-A-2001-133696 Onium salts and the like described in paragraph numbers [0030] to [0033] of the publication.

  Other examples of the acid generator include organometallic / organic halides described in JP-A-2002-29162, paragraphs [0059] to [0062], and a photoacid generator having an o-nitrobenzyl type protecting group. And compounds such as compounds that generate photosulfonic acid to generate sulfonic acid (iminosulfonate, etc.). Since many of these compounds are commercially available, such commercially available products can be used. Commercially available initiators include, for example, “Syracure UVI-6990” (trade name) sold by Dow Chemical Japan Co., Ltd., and “Adekaoptomer SP-150” (trade name) sold by ADEKA Corporation. Product name), “ADEKA OPTMER SP-300” (product name), “RHODORSIL PHOTOINITIAOR 2074” (product name) sold by Rhodia Japan Co., Ltd., and the like.

  As the acid, Bronsted acid such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid or the like, or organic acid such as acetic acid, formic acid, methanesulfonic acid, trifluoromethanesulfonic acid, paratoluenesulfonic acid, dibutyltin dilaurate, Examples thereof include Lewis acids such as dibutyltin diacetate, dibutyltin dioctate, triisopropoxyaluminum, tetrabutoxyzirconium, and tetrabutoxytitanate.

  Aromatic polycarboxylic acids such as pyromellitic acid, pyromellitic anhydride, trimellitic acid, trimellitic anhydride, phthalic acid, phthalic anhydride, or anhydrides thereof, maleic acid, maleic anhydride, succinic acid, succinic anhydride Aliphatic polycarboxylic acids such as or anhydrides thereof are also included.

  As an acid, only 1 type may be used and 2 or more types may be used together.

  These acids and photoacid generators are preferably added in a proportion of 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, with respect to 100 parts by mass of the cationic polymerizable compound. is there. When the addition amount is in the above range, it is preferable from the viewpoint of stability of the curable composition, polymerization reactivity, and the like.

(Radically polymerizable compound)
Moreover, the space | gap holding layer of this invention can also contain a radically polymerizable compound as a binder.

  Examples of the radical polymerizable group include ethylenically unsaturated groups such as a (meth) acryloyl group, a vinyloxy group, a styryl group, and an allyl group. Among them, a compound having a (meth) acryloyl group is preferable. The radical polymerizable compound preferably contains a polyfunctional monomer containing two or more radical polymerizable groups in the molecule. The polyfunctional acrylate is preferably selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate. Examples of the polyfunctional acrylate monomer include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate. , Tetramethylolmethane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, glycerin triacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol Ritolol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, Tetramethylol methane trimethacrylate, tetramethylol methane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, glycerol trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate Acrylate, dipentaerythritol penta methacrylate, dipentaerythritol hexa methacrylate, isobornyl acrylate and the like preferably. These compounds are used alone or in admixture of two or more. Moreover, oligomers, such as a dimer and a trimer of the said monomer, may be sufficient.

  Commercially available polyfunctional acrylates include Adekaoptomer KR / BY series: KR-400, KR-410, KR-550, KR-566, KR-567, BY-320B (Asahi Denka Co., Ltd.); Hard A-101-KK, A-101-WS, C-302, C-401-N, C-501, M-101, M-102, T-102, D-102, NS-101, FT-102Q8 MAG-1-P20, AG-106, M-101-C (manufactured by Guangei Chemical Co., Ltd.); Seika Beam PHC2210 (S), PHC X-9 (K-3), PHC2213, DP-10, DP-20 DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, SCR900 (manufactured by Dainichi Seika Kogyo Co., Ltd.); KRM7033, RM 7039, KRM 7130, KRM 7131, UVECRYL 29201, UVECRYL 29202 (manufactured by Daicel UCB); RC-5015, RC-5016, RC-5020, RC-5031, RC-5100, RC-5102, RC-5120, RC- 5122, RC-5152, RC-5171, RC-5180, RC-5181 (manufactured by Dainippon Ink & Chemicals, Inc.); 340 clear (manufactured by China Paint Co., Ltd.); Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (manufactured by Sanyo Chemical Industries); SP -1509, SP-1507 (manufactured by Showa Polymer Co., Ltd.); RCC-15C (manufactured by Grace Japan Co., Ltd.), Aronix M-6100, M-8030, M-8060 (manufactured by Toagosei Co., Ltd.); B420 (manufactured by Shin-Nakamura Chemical Co., Ltd.) or the like can be appropriately selected and used.

  The addition amount of the radical polymerizable compound is preferably 15% by mass or more and less than 70% by mass in the solid content in the low refractive layer coating composition from the viewpoint of the stability of the low refractive layer coating composition.

(Radical polymerization accelerator)
In order to accelerate the curing of the radical polymerizable compound, it is preferable to use a photopolymerization initiator in combination with the radical polymerizable compound. When the photopolymerization initiator and the radical polymerizable compound are used in combination, it is preferable to contain the photopolymerization initiator and the radical polymerizable compound in a mass ratio of 20: 100 to 0.01: 100.

  Specific examples of the photopolymerization initiator include acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof, but are not particularly limited thereto.

(Silicon compound)
The void retaining layer may contain an organosilicon compound represented by the following general formula (A), a hydrolyzate thereof, or a polycondensate thereof.

R2 _m SiX2 _4-m (A)
In the formula, R2 is an epoxy group, X2 is a hydroxyl group or a hydrolyzable substituent, and m is an integer of 0 to 3.

  R2 of the alkoxysilane compound having an epoxy group represented by the general formula (A) is not particularly limited, but examples thereof include 2-glycidoxyethyl group, 3-glycidoxypropyl group, 3-glycidoxybutyl group and the like. Glycidoxy C1-C4 alkyl group, preferably glycidoxy C1-C3 alkyl group, glycidyl group, 2- (3,4-epoxycyclohexyl) ethyl group, 3- (3,4-epoxycyclohexyl) propyl group, 2- (3 Oxiranes such as 4-epoxycycloheptyl) ethyl group, 2- (3,4-epoxycyclohexyl) propyl group, 2- (3,4-epoxycyclohexyl) butyl group, 2- (3,4-epoxycyclohexyl) pentyl group And a C1-C3 alkyl group substituted with a C5-C8 cycloalkyl group having a group. Among these, a 2-glycidoxyethyl group, a 3-glycidoxypropyl group, and a 2- (3,4-epoxycyclohexyl) ethyl group are preferable. Preferred specific examples of the compound that can be used as the compound of the general formula (1) having these substituents R2 include 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethyltriethoxysilane, and 3-glycidide. Xylpropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4) -epoxycyclohexylethyltriethoxysilane and the like. These may be used alone or in combination of two or more.

The alkoxysilane compound can be produced, for example, by the method described in JP-A-10-324749 and JP-A-6-298940. As described in JP-A-2006-348061, it can also be obtained by (co) condensation of an alkoxysilane compound of the general formula (1) under a base catalyst. In that case, water can be added as needed to promote (co) condensation. The amount of water added is usually 0.05 to 1.5 mol, preferably 0.1 to 1.2 mol, with respect to 1 mol of alkoxy groups in the entire reaction mixture. The catalyst used for the condensation reaction is not particularly limited as long as it is basic, but an inorganic base such as sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, etc. Organic bases such as ammonia, triethylamine, diethylenetriamine, n-butylamine, dimethylaminoethanol, triethanolamine, and tetramethylammonium hydroxide can be used. Among these, an inorganic base or ammonia is preferable because the catalyst can be easily removed from the product. The addition amount of the catalyst is usually 5 × 10 ^{−4 to} 7.5 mass%, preferably 1 × 10 ^{−3 to} 5 mass%, based on the amount of the alkoxysilane compound. The condensation reaction can be carried out without a solvent or in a solvent. There is no restriction | limiting in particular as a solvent in the case of using a solvent, if it is a solvent which melt | dissolves an alkoxysilane compound. Examples of such solvents include nonpolar solvents such as dimethylformamide, dimethylacetamide, tetrahydrofuran, methyl ethyl ketone, and methyl isobutyl ketone, and aromatic hydrocarbons such as toluene and xylene, preferably methyl ethyl ketone and methyl isobutyl ketone. .

  Furthermore, you may contain the fluorine substituted alkyl group containing silane compound represented by the following general formula (OSi-2).

  The fluorine-substituted alkyl group-containing silane compound represented by the general formula (OSi-2) will be described.

In the formula, R ^{1 to} R ⁶ are alkyl groups having 1 to 16 carbon atoms, preferably 1 to 4 carbon atoms, halogenated alkyl groups having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, and 6 to 12 carbon atoms, preferably 6 carbon atoms. 10 to 10 aryl groups, 7 to 14 carbon atoms, preferably 7 to 12 alkylaryl groups, arylalkyl groups, 2 to 8 carbon atoms, preferably 2 to 6 alkenyl groups, or 1 to 6 carbon atoms, preferably 1 to 3 alkoxy groups, a hydrogen atom or a halogen atom.

Rf represents-(CaHbFc)-, a is an integer of 1 to 12, b + c is 2a, b is an integer of 0 to 24, and c is an integer of 0 to 24. Such Rf is preferably a group having a fluoroalkylene group and an alkylene group. Specifically, examples of such fluorine-containing silicone compounds include (MeO) ₃ SiC ₂ H ₄ C ₂ F ₄ C ₂ H ₄ Si (MeO) ₃ , (MeO) ₃ SiC ₂ H ₄ C ₄ F ₈ C _{2 H 4 Si (MeO) 3} , (MeO) 3 SiC 2 H 4 C 6 F 12 C 2 H 4 Si (MeO) 3, (H 5 C 2 O) 3 SiC 2 H 4 C 4 F 8 C 2 H _{4 Si (OC 2 H 5)} 3, include methoxy disilane compound or the like represented by _{(H 5 C 2 O) 3} SiC 2 H 4 C 6 F 12 C 2 H 4 Si (OC 2 H 5) 3.

  The void retaining layer may contain a silane coupling agent. Silane coupling agents include methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane. Ethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropyltri Acetoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltri Ethoxysilane, γ- (β-glycidyloxyethoxy) propyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, γ- Acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, N- Examples include β- (aminoethyl) -γ-aminopropyltrimethoxysilane and β-cyanoethyltriethoxysilane.

  Examples of silane coupling agents having a disubstituted alkyl group with respect to silicon include dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, and γ-glycidyloxypropylmethyldiethoxysilane. Γ-glycidyloxypropylmethyldimethoxysilane, γ-glycidyloxypropylphenyldiethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldi Ethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimeth Shishiran, .gamma.-mercaptopropyl methyl diethoxy silane, .gamma.-aminopropyl methyl dimethoxy silane, .gamma.-aminopropyl methyl diethoxy silane, methyl vinyl dimethoxy silane, and methyl vinyl diethoxy silane.

  Among these, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, γ-acryloyloxypropyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane having a double bond in the molecule. Γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, and γ-methacryloyloxypropylmethyldiethoxy having a disubstituted alkyl group with respect to silicon Silane, methylvinyldimethoxysilane and methylvinyldiethoxysilane are preferred, and γ-acryloyloxypropyltrimethoxysilane and γ-methacryloyloxyp Particularly preferred are propyltrimethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane and γ-methacryloyloxypropylmethyldiethoxysilane.

  Two or more coupling agents may be used in combination. In addition to the silane coupling agents shown above, other silane coupling agents may be used. Other silane coupling agents include alkyl esters of orthosilicate (eg, methyl orthosilicate, ethyl orthosilicate, n-propyl orthosilicate, i-propyl orthosilicate, n-butyl orthosilicate, sec-butyl orthosilicate, orthosilicate). Acid t-butyl) and its hydrolyzate.

Further, the void holding layer may contain a silicon compound represented by CF ₃ (CF ₂ ) nCH ₂ CH ₂ Si (OR ₁ ) ₃ . (In the formula, R1 represents an alkyl group having 1 to 5 carbon atoms, and n represents an integer of 0 to 12.) Specific examples of the compound include trifluoropropyltrimethoxysilane and trifluoropropyl. Examples include triethoxysilane, tridecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltriethoxysilane, and these are used alone or in combination of two or more. Can be used. _{It may} also contain H 2 NCONH (CH) mSi ( OR2) silicon compound in the terminal position represented by ₃ having a ureido group _(H 2 NCONH-). (In the formula, R2 represents an alkyl group having 1 to 5 carbon atoms, and m represents an integer of 1 to 5.) Specific compounds include γ-ureidopropyltrimethoxysilane and γ-ureido. Examples thereof include propyltriethoxysilane and γ-ureidopropyltripropoxysilane. Among these, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, and the like are particularly preferable.

  In addition, as the binder, for example, polyvinyl alcohol, polyoxyethylene, polymethyl methacrylate, polymethyl acrylate, fluoroacrylate, diacetyl cellulose, triacetyl cellulose, nitrocellulose, polyester, alkyd resin, or the like can be used as the binder.

  It is preferable that a space | gap holding layer contains 5-95 mass% binder on the whole. The binder has a function of maintaining the structure of the void holding layer including voids. The usage-amount of a binder is suitably adjusted so that the intensity | strength of a space | gap holding layer can be maintained, without filling a space | gap.

(solvent)
When forming the void retaining layer, it is preferable to contain an organic solvent. Specific examples of organic solvents include alcohols (eg, methanol, ethanol, isopropanol, butanol, benzyl alcohol), ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), esters (eg, methyl acetate, ethyl acetate). , Propyl acetate, butyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate), aliphatic hydrocarbons (eg, hexane, cyclohexane), halogenated hydrocarbons (eg, methylene chloride, chloroform, carbon tetrachloride), aromatic Group hydrocarbon (eg, benzene, toluene, xylene), amide (eg, dimethylformamide, dimethylacetamide, n-methylpyrrolidone), ether (eg, diethyl ether, dioxane, tetrahydrofuran), ether alcohol (eg, 1-methoxy-2-propanol). Of these, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol are particularly preferable.

  The solid content concentration in the void-holding layer coating composition is preferably 1 to 4% by mass, and when the solid content concentration is 4% by mass or less, coating unevenness is less likely to occur and is 1% by mass or more. This reduces the drying load.

  The gap holding layer is coated with the coating composition for forming the gap holding layer using a known method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, and an ink jet method, and is heated and dried after coating. And it forms by carrying out a hardening process as needed.

  The coating amount is suitably 0.05 to 100 μm, preferably 0.1 to 50 μm, as the wet film thickness. Further, the solid content concentration of the coating composition is adjusted so that the dry film thickness becomes the above film thickness.

Moreover, you may include the process of heat-processing at the temperature of 50-160 degreeC after forming a space | gap holding layer. The period of the heat treatment may be appropriately determined depending on the set temperature. For example, if it is 50 ° C., it is preferably a period of 3 days or more and less than 30 days, and if it is 160 ° C., a range of 10 minutes or more and 1 day or less is preferable . Examples of the curing method include a method of thermosetting by heating, a method of curing by irradiation with light such as ultraviolet rays, and the like. When thermosetting, the heating temperature is preferably 50 to 300 ° C, preferably 60 to 250 ° C, and more preferably 80 to 150 ° C. When curing by light irradiation, exposure of the irradiation light is ^{preferably, 100mJ / cm 2 ~500mJ / cm} 2 and more preferably ^{10mJ / cm 2 ~10J / cm 2} .

Here, the wavelength range of the irradiated light is not particularly limited, but light having a wavelength in the ultraviolet region is preferably used. Specifically, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 5 to 500 mJ / cm ² , preferably 5 to 150 mJ / cm ² , and particularly preferably 20 to 100 mJ / cm ² .

  Between the gap holding layer and the film substrate, a hard coat layer, a high refractive index layer, an antistatic layer, or a back coat layer may be provided on the opposite side of the gap holding layer with the film substrate interposed therebetween. Good.

(Hard coat layer)
The hard coat layer is a thermoplastic acrylic resin such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, a radical polymerizable compound that can be used for the void retaining layer, It is preferable to use a binder such as a radical polymerization accelerator, a cationic polymerizable compound, a cationic polymerization accelerator, and other known thermoplastic resins, thermosetting resins, hydrophilic resins such as gelatin, and the like.

  Further, the hard coat layer may contain fine particles of an inorganic compound or an organic compound in order to adjust the scratch resistance, slipperiness and refractive index.

  Examples of inorganic fine particles used in the hard coat layer include silicon oxide, titanium oxide, aluminum oxide, tin oxide, indium oxide, ITO, zinc oxide, zirconium oxide, magnesium oxide, calcium carbonate, calcium carbonate, talc, clay, and calcined kaolin. And calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. In particular, silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide and the like are preferably used.

  Organic particles include polymethacrylic acid methyl acrylate resin powder, acrylic styrene resin powder, polymethyl methacrylate resin powder, silicon resin powder, polystyrene resin powder, polycarbonate resin powder, benzoguanamine resin powder, melamine resin powder. An ultraviolet curable resin composition such as polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, or polyfluoroethylene resin powder can be added. Particularly preferred are cross-linked polystyrene particles (for example, SX-130H, SX-200H, SX-350H, manufactured by Soken Chemical), polymethyl methacrylate-based particles (for example, MX150, MX300, manufactured by Soken Chemical), and fluorine-containing acrylic resin fine particles. . Examples of the fluorine-containing acrylic resin fine particles include commercial products such as FS-701 manufactured by Nippon Paint. Examples of the acrylic particles include Nippon Paint: S-4000, and examples of the acrylic-styrene particles include Nippon Paint: S-1200, MG-251.

  The average particle diameter of these fine particle powders is preferably 0.01 to 5 μm, more preferably 0.1 to 5.0 μm, and particularly preferably 0.1 to 4.0 μm. Moreover, it is preferable to contain 2 or more types of microparticles | fine-particles from which a particle size differs. The proportion of the ultraviolet curable resin composition and the fine particles is desirably blended so as to be 0.1 to 30 parts by mass with respect to 100 parts by mass of the resin composition.

  In order to increase the heat resistance of the hard coat layer, an antioxidant that does not inhibit the photocuring reaction can be selected and used. Examples include hindered phenol derivatives, thiopropionic acid derivatives, phosphite derivatives, and the like.

  Further, the hard coat layer preferably contains a silicone surfactant or a polyoxyether compound. As the silicone surfactant, polyether-modified silicone is preferable. Specifically, BYK-UV3500, BYK-UV3510, BYK-333, BYK-331, BYK-337 (manufactured by BYK-Chemical Japan), TSF4440, TSF4445, TSF4446, TSF4452, TSF4460 (manufactured by GE Toshiba Silicone), KF-351, KF-351A, KF-352, KF-353, KF-354, KF-355, KF-615, KF-618, KF-945, KF- 6004 (polyether-modified silicone oil; manufactured by Shin-Etsu Chemical Co., Ltd.) and the like are exemplified, but not limited thereto.

  Of the polyoxyether compounds, the polyoxyethylene oleyl ether compound is preferable, and is generally a compound represented by the general formula (α).

Formula (α) C ₁₈ H ₃₅ —O (C ₂ H ₄ O) nH
In the formula, n represents 2 to 40.

  The average addition number (n) of ethylene oxide with respect to the oleyl part is 2 to 40, preferably 2 to 10, more preferably 2 to 9, and further preferably 2 to 8. The compound of the general formula (α) can be obtained by reacting ethylene oxide with oleyl alcohol.

  Specific products include Emulgen 404 (polyoxyethylene (4) oleyl ether), Emulgen 408 (polyoxyethylene (8) oleyl ether), Emulgen 409P (polyoxyethylene (9) oleyl ether), Emulgen 420 (polyoxy) Ethylene (13) oleyl ether), Emulgen 430 (polyoxyethylene (30) oleyl ether) or more, Kao Corporation, NOFBLEEAO-9905 (polyoxyethylene (5) oleyl ether) manufactured by NOF Corporation.

  Note that () represents the number n. Nonionic polyoxyether compounds may be used alone or in combination of two or more.

  These improve applicability | paintability and it is preferable to add these components in 0.01-3 mass% with respect to the solid content component in a coating liquid.

  Further, the hard coat layer may contain a fluorine-siloxane graft polymer.

  The fluorine-siloxane graft polymer refers to a copolymer polymer obtained by grafting polysiloxane containing siloxane and / or organosiloxane alone and / or organopolysiloxane to at least a fluorine-based resin. Examples of commercially available products include ZX-022H, ZX-007C, ZX-049, and ZX-047-D manufactured by Fuji Kasei Kogyo Co., Ltd. These compounds may be used as a mixture. Fluorine-siloxane graft polymer should be used in a coating solution that has a mass ratio of actinic ray curable resin to fluorine-siloxane graft polymer: energy-active radiation curable resin = 0.05: 100 to 5.00: 100. To preferred.

  The hard coat layer may have a laminated structure of two or more layers. In the present invention, the hard coat layer is made of a laminate, and the hard coat layer adjacent to the film base contains a thermoplastic acrylic resin, so that the objective effect of the present invention can be exhibited even under more severe test conditions. This is preferable.

  One or all of the layers may be a so-called conductive layer containing, for example, conductive fine particles, a π-conjugated conductive polymer, or an ionic polymer. Examples of the π-conjugated conductive polymer include polythiophene, poly (3-methylthiophene), poly (3-ethylthiophene), poly (3-propylthiophene), poly (3-butylthiophene), and poly (3-hexylthiophene). , Poly (3-octylthiophene), poly (3-decylthiophene), poly (3-dodecylthiophene), poly (3-bromothiophene), poly (3-chlorothiophene), poly (3-cyanothiophene), poly (3-phenylthiophene), poly (3,4-dimethylthiophene), poly (3,4-dibutylthiophene), poly (3-hydroxythiophene), poly (3-methoxythiophene), poly (3-ethoxythiophene) , Poly (3-butoxythiophene), poly (3-hexyloxythiophene), poly (3 Octyloxythiophene), poly (3-decyloxythiophene), poly (3-dodecyloxythiophene), poly (3,4-dihydroxythiophene), poly (3,4-dimethoxythiophene), poly (3,4-di Ethoxythiophene), poly (3,4-dipropoxythiophene), poly (3,4-dibutoxythiophene), poly (3,4-dihexyloxythiophene), poly (3,4-dioctyloxythiophene), poly ( 3,4-didecyloxythiophene), poly (3,4-didodecyloxythiophene), poly (3,4-ethylenedioxythiophene), poly (3,4-propylenedioxythiophene), poly (3,4 4-butenedioxythiophene), poly (3-methyl-4-methoxythiophene), poly (3-methyl-4 -Ethoxythiophene), poly (3-carboxythiophene), poly (3-methyl-4-carboxythiophene), poly (3-methyl-4-carboxyethylthiophene), poly (3-methyl-4-carboxybutylthiophene) , Polypyrrole, poly (N-methylpyrrole), poly (3-methylpyrrole), poly (3-ethylpyrrole), poly (3-N-propylpyrrole), poly (3-butylpyrrole), poly (3-octyl) Pyrrole), poly (3-decylpyrrole), poly (3-dodecylpyrrole), poly (3,4-dimethylpyrrole), poly (3,4-dibutylpyrrole), poly (3-carboxypyrrole), poly (3 -Methyl-4-carboxypyrrole), poly (3-methyl-4-carboxyethylpyrrole), poly (3-methyl 4-carboxybutylpyrrole), poly (3-hydroxypyrrole), poly (3-methoxypyrrole), poly (3-ethoxypyrrole), poly (3-butoxypyrrole), poly (3-hexyloxypyrrole), poly ( 3-methyl-4-hexyloxypyrrole), polyaniline, poly (2-methylaniline), poly (3-isobutylaniline), poly (2-anilinesulfonic acid), poly (3-anilinesulfonic acid) and the like. . Each of these may be used alone or two types of copolymers can be suitably used.

  As the coating method of the hard coat layer coating solution, the above-described methods can be used. The coating amount is suitably 0.1 to 40 μm, preferably 0.5 to 30 μm, as the wet film thickness. Moreover, it is preferable that it is the range of 1-20 micrometers as a dry film thickness.

  The hard coat layer has a center line average roughness (Ra) defined by JIS B 0601 of 0.001 to 0.1 μm, or a fine hard coat layer and Ra is adjusted to 0.1 to 1 μm. An antiglare hard coat layer may also be used. The center line average roughness (Ra) is preferably measured by an optical interference type surface roughness measuring instrument, and can be measured, for example, using a non-contact surface fine shape measuring device WYKO NT-2000 manufactured by WYKO.

(High refractive index layer)
The high refractive index layer preferably contains metal oxide fine particles. The kind of metal oxide fine particles is not particularly limited, and Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P and S A metal oxide having at least one element selected from the group consisting of Al, In, Sn, Sb, Nb, a halogen element, Ta and the like is doped with a minute amount of atoms. May be. A mixture of these may also be used. In the present invention, at least one metal oxide fine particle selected from among zirconium oxide, antimony oxide, tin oxide, zinc oxide, indium-tin oxide (ITO), antimony-doped tin oxide (ATO), and zinc antimonate is used. It is particularly preferable to use it as the main component. In particular, it is preferable to contain zinc antimonate particles.

  The average particle diameter of the primary particles of these metal oxide fine particles is in the range of 10 nm to 200 nm, particularly preferably 10 to 150 nm. The average particle diameter of the metal oxide fine particles can be measured from an electron micrograph taken with a scanning electron microscope (SEM) or the like. You may measure by the particle size distribution meter etc. which utilize a dynamic light scattering method, a static light scattering method, etc. If the particle size is too small, aggregation tends to occur and the dispersibility deteriorates. If the particle size is too large, the haze is remarkably increased. The shape of the metal oxide fine particles is preferably a rice grain shape, a spherical shape, a cubic shape, a spindle shape, a needle shape, or an indefinite shape.

  Specifically, the refractive index of the high refractive index layer is higher than the refractive index of the film as the support, and is preferably in the range of 1.5 to 2.2 when measured at 23 ° C. and a wavelength of 550 nm. The means for adjusting the refractive index of the high refractive index layer is that the kind and addition amount of the metal oxide fine particles are dominant, so that the refractive index of the metal oxide fine particles is preferably 1.80 to 2.60, More preferably, it is 1.85 to 2.50.

(Antistatic layer)
The antistatic layer cures zinc antimonate sol, tin phosphate sol, tin oxide sol, π-conjugated conductive polymer, ionic polymer compound, etc. through a crosslinking reaction or the like by irradiation with active rays such as ultraviolet rays and electron beams. It is preferable to contain in resin.

The antistatic layer imparts a function of preventing the film from being charged when the support (resin film or the like) is handled. The surface resistivity of the antistatic layer is preferably adjusted to 10 ¹¹ Ω / □ (25 ° C., 55% RH) or less, and more preferably 10 ¹⁰ Ω / □ (25 ° C., 55% RH) or less. Particularly preferably, it is 10 ⁹ Ω / □ (25 ° C., 55% RH) or less.

  Here, although details of the measurement of the surface specific resistance value are described in the Examples, the sample was conditioned for 24 hours under the conditions of 25 ° C. and 55% RH, and a terraohm meter model VE-30 manufactured by Kawaguchi Electric Co., Ltd. was used. Use to measure.

  On the conductive layer, an overcoat layer is further provided as the outermost surface layer. The surface specific resistance value is measured by substantially conducting the surface specific resistance value on the outermost surface layer on the side where the conductive layer is provided. It is defined as the surface resistivity value of the conductive layer.

(Back coat layer)
The back coat layer is provided in order to correct the curl generated by providing the void retaining layer. That is, the degree of curling can be balanced by imparting the property of being rounded with the surface on which the backcoat layer is provided facing inward.

  The backcoat layer is preferably applied also as an antiblocking layer, and in this case, particles of an inorganic compound or an organic compound are added to the backcoat layer coating composition in order to provide an antiblocking function. Is preferred. Examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, tin oxide, indium oxide, zinc oxide, ITO, hydrated silica Mention may be made of calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate.

  These inorganic compounds are commercially available, for example, under the trade names Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.). it can.

  Examples of the solvent used for coating the backcoat layer include dioxane, acetone, methyl ethyl ketone, methyl isobutyl ketone, N, N-dimethylformamide, methyl acetate, ethyl acetate, trichloroethylene, methylene chloride, ethylene chloride, tetrachloroethane, trichloroethane, Examples include chloroform, water, methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butanol, cyclohexanone, cyclohexanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, or hydrocarbons (toluene, xylene). Are used in appropriate combinations.

  It is preferable to apply these coating compositions on the surface of the hard coat film with a gravure coater, dip coater, reverse coater, wire bar coater, die coater, spray coating, ink jet coating or the like with a wet film thickness of 1 to 100 μm. Is particularly preferably 5 to 30 μm.

  Examples of the resin used as the binder of the backcoat layer include vinyl chloride-vinyl acetate copolymer, vinyl chloride resin, vinyl acetate resin, vinyl acetate-vinyl alcohol copolymer, partially hydrolyzed vinyl chloride-vinyl acetate copolymer. Polymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, ethylene-vinyl alcohol copolymer, chlorinated polyvinyl chloride, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, etc. Vinyl polymer or copolymer, nitrocellulose, cellulose acetate propionate (preferably acetyl group substitution degree 1.8-2.3, propionyl group substitution degree 0.1-1.0), diacetyl cellulose, cellulose Cellulose derivatives such as acetate butyrate resin, maleic acid and / or Or acrylic acid copolymer, acrylic ester copolymer, acrylonitrile-styrene copolymer, chlorinated polyethylene, acrylonitrile-chlorinated polyethylene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, acrylic resin , Polyvinyl alcohol resin, polyvinyl acetal resin, polyvinyl butyral resin, urethane resin, polyester polyurethane resin, polyether polyurethane resin, polycarbonate polyurethane resin, polyester resin, polyether resin, polyamide resin, amino resin, styrene-butadiene resin, butadiene-acrylonitrile Examples thereof include, but are not limited to, rubber resins such as resins, silicone resins, fluorine resins, and the like.

  As the binder, it is preferable to use a blend of acetylated cellulose such as cellulose diacetate and cellulose acetate proionate and an acrylic resin, and the refractive index difference between the fine particles and the binder is 0 to 0 using fine particles made of acrylic resin. By setting it to less than 0.02, a highly transparent back coat layer can be obtained.

  You may surface-treat before apply | coating each said layer. Examples of the surface treatment method include a cleaning method, an alkali treatment method, a flame plasma treatment method, a high frequency discharge plasma method, an electron beam method, an ion beam method, a sputtering method, an acid treatment, a corona treatment method, and an atmospheric pressure glow discharge plasma method. It is done.

(Reflectance)
The reflectance of the 1st protective film which has a space | gap holding layer can be measured with a spectrophotometer and a spectrocolorimeter. At that time, after the surface on the measurement side of the sample is roughened, light absorption treatment with black spray or light absorption treatment by attaching a black acrylic plate is performed, and then the visible light region (400 to 700 nm). Measure the reflected light.

  The first protective film of the present invention is preferably as low as possible, but the average value in the visible light region wavelength is 2.0% or less when used as the outermost surface of an image display device such as an LCD. It is preferable from the viewpoint that an external light reflection preventing function can be suitably obtained. The minimum reflectance is preferably 0.8% or less.

  Moreover, it is preferable to have a flat reflection spectrum in the wavelength region of visible light. In addition, the reflection hue on the surface of the display device that has been subjected to the antireflection treatment is often colored red or blue because the reflectance in the short wavelength region and the long wavelength region is high in the visible light region due to the design of the antireflection film. The color tone of the reflected light varies depending on the application, and when used on the outermost surface of a flat-screen television or the like, a neutral color tone is preferred. In this case, generally preferred reflection hue ranges are 0.17 ≦ x ≦ 0.27 and 0.07 ≦ y ≦ 0.17 on the XYZ color system (CIE1931 color system). Further, the range in which the distance Δxy of (x, y) = (0.31, 0.31) on the xy plane is 0.05 or less is preferable because it is closer to neutral with no color, and 0.03 or less is preferable. Further preferred. The color tone can be calculated from the refractive index of each layer in accordance with a conventional method in consideration of the reflectance and the color of reflected light.

(surface hardness)
The surface hardness of the first protective film in the present invention can be expressed by pencil hardness, and is preferably 2H to 8H because it is difficult to be scratched in use on the surface of a display device such as an LCD or in a polarizing plate forming step. It is a structure, More preferably, it is 3H-8H, More preferably, it is 4H-8H.

  The pencil hardness is specified by JIS K 5400 using a test pencil specified by JIS S 6006 after the prepared protective film sample is conditioned at a temperature of 23 ° C. and a relative humidity of 55% for 24 hours or more. It is the value measured according to the evaluation method.

<Film base>
As a film base used in the first protective film of the present invention, preferable requirements include ease of production, optical isotropy, optical transparency, and the like.

  The term “transparent” as used herein means that the visible light transmittance is 60% or more, preferably 80% or more, and particularly preferably 90% or more.

  Although it will not specifically limit if it has said property, For example, cellulose ester-type films, such as a cellulose diacetate film, a cellulose triacetate film, a cellulose acetate propionate film, a cellulose acetate butyrate film, a polyester-type film, a polycarbonate Film, polyarylate film, polysulfone (including polyethersulfone) film, polyester film such as polyethylene terephthalate and polyethylene naphthalate, polyethylene film, polypropylene film, cellophane, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol Film, syndiotactic polystyrene film, cycloolefin polymer fill (Arton (manufactured by JSR)), ZEONEX, ZEONOR (manufactured by Nippon Zeon), polyvinyl acetal, polymethylpentene film, polyetherketone film, polyetherketoneimide film, polyamide film, fluororesin film, nylon film, A polymethyl methacrylate film, an acrylic film, a glass plate, etc. can be mentioned.

  Among these, a cellulose ester film, a polycarbonate film, a polysulfone (including polyether sulfone) film, and a cycloolefin polymer film are preferable.

  In particular, it is preferable to use a cellulose ester film (hereinafter also referred to as a cellulose ester film) as the film substrate.

  Cellulose ester film (for example, Konica Minolta Tack, product names KC8UX, KC4UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UY, KC4UE, KC12UR (above, manufactured by Konica Minolta Opto Co., Ltd., cost) From the viewpoints of transparency, adhesiveness and the like, it is preferably used.

  Hereinafter, the cellulose ester film which is a preferable film substrate will be described in detail.

  The cellulose ester film may be a film produced by melt casting film formation or a film produced by solution casting film formation.

  As the cellulose ester, cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate are preferable. Among them, cellulose acetate butyrate, cellulose acetate phthalate, and cellulose acetate propionate are preferably used.

  In particular, when the substitution degree of the acetyl group is X and the substitution degree of the propionyl group or butyryl group is Y, it is preferable to use a cellulose ester film in which X and Y are in the following ranges.

2.3 ≦ X + Y ≦ 3.0
0.1 ≦ Y ≦ 2.0
In particular,
2.5 ≦ X + Y ≦ 2.9
0.1 ≦ Y ≦ 1.2
It is preferable that

  In addition, the measuring method of the substitution degree of an acyl group can be measured according to the prescription | regulation of ASTM-D817-96.

  The number average molecular weight of the cellulose ester is preferably 50000 to 250,000, since it has a high mechanical strength when molded and an appropriate dope viscosity, and more preferably 80000 to 150,000.

  Since the average molecular weight and molecular weight distribution of the cellulose ester can be measured using high performance liquid chromatography, the number average molecular weight (Mn) and the mass average molecular weight (Mw) can be calculated using this, and the ratio can be calculated.

  The measurement conditions are as follows.

Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Sciences)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) Mw = 1,000,000-500 calibration curves with 13 samples were used. The 13 samples are preferably used at approximately equal intervals.

  The raw material cellulose of the cellulose ester may be wood pulp or cotton linter, and the wood pulp may be softwood or hardwood, but softwood is more preferable. A cotton linter is preferably used from the viewpoint of peelability during film formation. The cellulose ester made from these can be mixed suitably or can be used independently.

  For example, the ratio of cellulose ester derived from cellulose linter: cellulose ester derived from wood pulp (coniferous): cellulose ester derived from wood pulp (hardwood) is 100: 0: 0, 90: 10: 0, 85: 15: 0, 50:50: 0, 20: 80: 0, 10: 90: 0, 0: 100: 0, 0: 0: 100, 80:10:10, 85: 0: 15, 40:30:30.

  Moreover, a cellulose-ester film may contain the acrylic resin mentioned later.

(acrylic resin)
Acrylic resin also includes methacrylic resin. Although it does not restrict | limit especially as resin, What consists of 50-99 mass% of methyl methacrylate units and 1-50 mass% of other monomer units copolymerizable with this is preferable.

  Other monomers that can be copolymerized include alkyl methacrylates having 2 to 18 carbon atoms, alkyl acrylates having 1 to 18 carbon atoms, acrylic acid, methacrylic acid, and the like. Saturated acids, maleic acids, fumaric acids, unsaturated divalent carboxylic acids such as itaconic acid, aromatic vinyl compounds such as styrene, α-methylstyrene, and nucleus-substituted styrene, α, β- such as acrylonitrile, methacrylonitrile, etc. Examples thereof include unsaturated nitrile, maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride, and the like. These can be used alone or in combination of two or more.

  Among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer. n-Butyl acrylate is particularly preferably used.

  The acrylic resin preferably has a weight average molecular weight (Mw) of 80000 to 1000000 from the viewpoint of mechanical strength as a film and fluidity when producing the film. A weight average molecular weight (Mw) can be measured using said high performance liquid chromatography.

  There is no restriction | limiting in particular as a manufacturing method of an acrylic resin (A), You may use any well-known methods, such as suspension polymerization, emulsion polymerization, block polymerization, or solution polymerization. Here, as a polymerization initiator, a normal peroxide type and an azo type can be used, and a redox type can also be used. Regarding the polymerization temperature, suspension or emulsion polymerization may be performed at 30 to 100 ° C, and bulk or solution polymerization may be performed at 80 to 160 ° C. Further, in order to control the reduced viscosity of the produced copolymer, polymerization can be carried out using alkyl mercaptan or the like as a chain transfer agent. With this molecular weight, both heat resistance and brittleness can be achieved. A commercially available thing can also be used as an acrylic resin. For example, Delpet 60N, 80N (Asahi Kasei Chemicals Co., Ltd.), Dialal BR52, BR80, BR83, BR85, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Electrochemical Industry Co., Ltd.) and the like can be mentioned. .

  Furthermore, it is preferable to contain acrylic particles from the viewpoint of the brittleness resistance and surface hardness of the film substrate.

  Next, the acrylic particles will be described. Acrylic particles, for example, a PTFE membrane having a pore diameter less than the average particle diameter of acrylic particles when a predetermined amount of the prepared acrylic resin-containing film is collected, dissolved in a solvent, stirred, and sufficiently dissolved and dispersed. It is preferable that the weight of the insoluble matter filtered and collected using a filter is 90% by mass or more of the acrylic particles added to the acrylic resin-containing film.

  The acrylic particles are not particularly limited, but are preferably acrylic particles having a layer structure of two or more layers, and particularly preferably the following multilayer structure acrylic granular composite.

  The multilayer structure acrylic granular composite is formed by laminating the innermost hard layer polymer, the cross-linked soft layer polymer exhibiting rubber elasticity, and the outermost hard layer polymer from the central portion toward the outer peripheral portion. This refers to a particulate acrylic polymer having a structure.

  A commercially available thing can also be used as an acrylic particle. For example, metabrene W-341 (C2) (manufactured by Mitsubishi Rayon Co., Ltd.), Chemisnow MR-2G (C3), MS-300X (C4) (manufactured by Soken Chemical Co., Ltd.) and the like can be mentioned.

  The acrylic particles preferably contain 0.5 to 45% by mass of acrylic particles with respect to the total mass of the cellulose ester resin and the acrylic resin.

  Moreover, the film which consists of a cellulose-ester resin and an acrylic resin (henceforth a cellulose-ester resin and an acrylic resin film) has a tension softening point of 105-145 degreeC, and a film which does not produce a ductile fracture is preferable. Ductile fracture is caused by the application of a greater stress than the strength of a certain material, and is defined as a fracture that involves significant elongation or drawing of the material before final fracture. As a specific measurement method of the tension softening point temperature, for example, using a Tensilon tester (ORIENTEC Co., RTC-1225A), the acrylic resin-containing film is cut out at 120 mm (length) × 10 mm (width), and 10N The temperature can be raised at a rate of 30 ° C./min while pulling with tension, and the temperature at 9 N is measured three times, and the average value can be obtained.

  Moreover, it is preferable that the film consisting of a cellulose ester resin and an acrylic resin has a glass transition temperature (Tg) of 110 ° C. or higher. More preferably, it is 120 ° C. or higher. Especially preferably, it is 150 degreeC or more.

  The glass transition temperature is determined by using a differential scanning calorimeter (DSC-7, manufactured by Perkin Elmer) at a heating rate of 20 ° C./min, and determined in accordance with JIS K7121 (1987). Tmg).

  A film composed of a cellulose ester resin and an acrylic resin preferably has a breaking elongation in at least one direction of 10% or more, more preferably 20% or more, in the measurement based on JIS-K7127-1999. The upper limit of the elongation at break is not particularly limited, but is practically about 250%. In order to increase the elongation at break, it is effective to suppress defects in the film caused by foreign matter and foaming. The thickness of the film made of cellulose ester resin and acrylic resin is preferably 20 μm or more.

  More preferably, it is 30 μm or more. The upper limit of the thickness is not particularly limited, but in the case of forming a film by a solution casting method, the upper limit is about 250 μm from the viewpoint of applicability, foaming, solvent drying, and the like. The thickness of the film can be appropriately selected depending on the application.

  The film comprising a cellulose ester resin and an acrylic resin preferably contains an acrylic resin and a cellulose ester resin in a mass ratio of 95: 5 to 30:70 from the viewpoint of both workability and heat resistance. The total substitution degree (T) of the acyl group is 2.00 to 3.00, the acetyl group substitution degree (ac) is 0 to 1.89, the number of carbons of the acyl group other than the acetyl group is 3 to 7, and the weight The average molecular weight (Mw) is preferably 75,000 to 280000. Moreover, the total mass of an acrylic resin and a cellulose-ester resin is 55-100 mass% of an acrylic resin containing film, Preferably it is 60-99 mass%.

  A film made of a cellulose ester resin and an acrylic resin may contain other acrylic resins.

  A cellulose ester film or a film made of a cellulose ester resin and an acrylic resin may be produced by a solution casting method or a melt casting method. For example, when cellulose ester is used as a film base material In the case of cellulose ester, the solvent used for dissolution tends to remain. The elastic modulus of the film is lowered due to the influence of the remaining solvent, and plastic deformation is likely to occur. Therefore, it is preferable to prepare the film by a melt casting method. Methods formed by melt casting can be classified into melt extrusion molding methods, press molding methods, inflation methods, injection molding methods, blow molding methods, stretch molding methods, and the like. Among these, the melt extrusion method is preferable, in which a film having excellent mechanical strength and surface accuracy can be obtained.

  In the present invention, a method of forming a film after the film forming material is heated to exhibit its fluidity and then extruded onto a drum or an endless belt is also included as a melt casting film forming method.

  Further, in film formation of the film substrate, it is preferable to stretch at least in the width direction, and in the solution casting process, 1.01-1 in the width direction when the amount of residual peeling is 3 to 40% by mass. The film is preferably stretched 5 times. More preferably, it is biaxially stretched in the width direction and the lengthwise direction, and when the amount of residual dissolution is 3 to 40% by mass, it is stretched by 1.01 to 1.5 times in the width direction and the lengthwise direction, respectively. It is to be.

  In particular, the above stretching operation is preferably used to adjust the retardation.

  Although the film thickness of a film base material is not specifically limited, the thing of the range of 10-200 micrometers is used. In particular, the film thickness is particularly preferably 10 to 100 μm. More preferably, it is 20-80 micrometers.

  The length of the film substrate is preferably 100 m to 5000 m, and the width is preferably 1.2 m or more, more preferably 1.4 to 4 m. By making the length and width of the film base within the above ranges, the handleability and productivity are excellent. The film substrate is preferably a transparent support having a light transmittance of 90% or more, more preferably 93% or more.

(Plasticizer)
The film substrate preferably contains the following plasticizer. Examples of plasticizers include phosphate ester plasticizers, phthalate ester plasticizers, trimellitic acid ester plasticizers, pyromellitic acid plasticizers, glycolate plasticizers, citrate ester plasticizers, and polyesters. A plasticizer, a polyhydric alcohol ester plasticizer, and the like can be preferably used.

  For phosphate plasticizers, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenylbiphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc. For phthalate ester plasticizers, diethyl phthalate, dimethoxy Ethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, diphenyl phthalate, dicyclohexyl phthalate, and other trimellitic acid plasticizers include tributyl trimellitate, triphenyl trimellitate, triethyl For pyromellitic acid ester plasticizers such as trimellitate, tetrabutylpyromellitate, In the case of glycolate plasticizers such as lupyromelitate and tetraethylpyromellitate, triacetin, tributyrin, ethylphthalylethyl glycolate, methylphthalylethylglycolate, butylphthalylbutylglycolate, etc. Citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tri-n-butyl citrate, acetyl tri-n- (2-ethylhexyl) citrate and the like can be preferably used. Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters.

  As the polyester plasticizer, a copolymer of a dibasic acid and a glycol such as an aliphatic dibasic acid, an alicyclic dibasic acid, or an aromatic dibasic acid can be used. The aliphatic dibasic acid is not particularly limited, and adipic acid, sebacic acid, phthalic acid, terephthalic acid, 1,4-cyclohexyl dicarboxylic acid, and the like can be used. As glycol, ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol and the like can be used. These dibasic acids and glycols may be used alone or in combination of two or more.

  The polyhydric alcohol ester plasticizer comprises an ester of a divalent or higher aliphatic polyhydric alcohol and a monocarboxylic acid. Examples of preferred polyhydric alcohols include the following, but the present invention is not limited to these. Adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3- Butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, 2-n-butyl-2-ethyl- Examples include 1,3-propanediol, galactitol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, xylitol, and the like. In particular, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, and xylitol are preferable. There is no restriction | limiting in particular as monocarboxylic acid used for polyhydric alcohol ester, Well-known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid, etc. can be used. Use of an alicyclic monocarboxylic acid or aromatic monocarboxylic acid is preferred in terms of improving moisture permeability and retention. Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto. As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. It is more preferable that it is C1-C20, and it is especially preferable that it is C1-C10. When acetic acid is contained, the compatibility with the cellulose ester is increased, and it is also preferable to use a mixture of acetic acid and another monocarboxylic acid. Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid, Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, and laccelic acid, undecylenic acid, olein Examples thereof include unsaturated fatty acids such as acid, sorbic acid, linoleic acid, linolenic acid, and arachidonic acid. Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof. Examples of preferred aromatic monocarboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenyl carboxylic acid, naphthalene carboxylic acid, and tetralin carboxylic acid. And aromatic monocarboxylic acids possessed by them, or derivatives thereof. Particularly preferred is benzoic acid. The molecular weight of the polyhydric alcohol ester is not particularly limited, but is preferably in the range of 300 to 1500, and more preferably in the range of 350 to 750. The larger one is preferable in terms of improvement in retention, and the smaller one is preferable in terms of moisture permeability and compatibility with cellulose ester.

  The carboxylic acid used for the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified with carboxylic acid, or a part of the OH groups may be left as they are. These plasticizers are preferably used alone or in combination. The amount of these plasticizers used is preferably from 1 to 20% by mass, particularly preferably from 3 to 13% by mass, based on the cellulose ester, in terms of film performance, processability and the like.

(UV absorber)
The film substrate may contain an ultraviolet absorber. Next, the ultraviolet absorber will be described.

  As the ultraviolet absorber, those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties.

  Specific examples include, but are not limited to, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex compounds, and the like.

  Although the following specific examples are given as a benzotriazole type ultraviolet absorber, this invention is not limited to these.

UV-1: 2- (2'-hydroxy-5'-methylphenyl) benzotriazole UV-2: 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole UV-3 : 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole UV-4: 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl)- 5-Chlorobenzotriazole UV-5: 2- (2'-hydroxy-3 '-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl) benzotriazole UV-6: 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol)
UV-7: 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole UV-8: 2- (2H-benzotriazol-2-yl) -6 (Linear and side chain dodecyl) -4-methylphenol (TINUVIN171, manufactured by Ciba Japan)
UV-9: Octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H-benzotriazol-2-yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl- Mixture of 4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate (TINUVIN109, manufactured by Ciba Japan)
Moreover, although the following specific examples are shown as a benzophenone series ultraviolet absorber, this invention is not limited to these.

UV-10: 2,4-dihydroxybenzophenone UV-11: 2,2'-dihydroxy-4-methoxybenzophenone UV-12: 2-hydroxy-4-methoxy-5-sulfobenzophenone UV-13: Bis (2-methoxy -4-hydroxy-5-benzoylphenylmethane)
As the UV absorber, a benzotriazole UV absorber and a benzophenone UV absorber, which are highly transparent and excellent in preventing the deterioration of polarizing plates and liquid crystals, are preferable, and benzotriazole UV absorption with less unnecessary coloring is preferable. An agent is particularly preferably used.

  Further, an ultraviolet absorber having a distribution coefficient of 9.2 or more described in Japanese Patent Application No. 11-295209 can be used, and in particular, an ultraviolet absorber having a distribution coefficient of 10.1 or more is the surface quality of the film substrate. Is preferable from the standpoint that it can be maintained well.

  Moreover, the polymer ultraviolet absorber (or the general formula (1) or the general formula (2) of JP-A-6-148430 and the general formulas (3), (6) and (7) described in Japanese Patent Application No. 2000-156039 (or A UV-absorbing polymer) is also preferably used. As a polymer ultraviolet absorber, PUVA-30M (manufactured by Otsuka Chemical Co., Ltd.) and the like are commercially available.

  Moreover, you may give an internal haze to a film base material.

(particle)
Internal haze, for example, by adding particles with a refractive index different from that of the film base to the film base and controlling the addition amount and particle size of the particles, generating haze due to internal scattering, and adjusting this Can be achieved. The particles are classified into inorganic particles and organic particles. The inorganic particles are not particularly limited, and examples thereof include silicon oxide, titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, barium sulfate, talc, kaolin, and calcium sulfate. The organic particles are not particularly limited. For example, fluorinated acrylic resin powder, polystyrene resin powder, polymethacrylic acid methyl acrylate resin powder, silicone resin powder, polycarbonate resin powder, acrylic styrene resin powder, benzoguanamine resin Examples thereof include powder, melamine resin powder, polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, and polyfluoroethylene resin powder. These inorganic particles and organic particles may be used in combination of two or more different types and average particle diameters, and those obtained by surface-treating the surface of the particles with an organic substance are also preferably used.

  Particularly preferred inorganic particles are silicon dioxide. Specific examples of silicon dioxide include Aerosil 200V, Aerosil R972V, Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd.), Sea Hoster KEP-10, Sea Hoster KEP-30, Commercial products having trade names such as Seahoster KEP-50 (above, made by Nippon Shokubai Co., Ltd.), Silo Hovic 100 (made by Fuji Silysia), Nip Seal E220A (made by Nippon Silica Kogyo), Admafine SO (made by Admatechs), etc. Can be preferably used. The shape of the particles can be used without any particular limitation, such as indefinite shape, needle shape, flat shape, spherical shape, etc. However, the use of spherical particles is particularly preferable because it is easy to adjust the haze.

  The average particle size of the particles added to the support is preferably from 0.3 to 1 μm, more preferably from 0.4 to 0.7 μm.

  The average particle size can be determined by visual observation from an image photograph of secondary electron emission obtained by scanning electron microscope (SEM) or the like of 500 particles or by image processing, or by dynamic light scattering, static It can be measured by a particle size distribution meter using an automatic light scattering method or the like. The average particle diameter here refers to the number average particle diameter. In addition, an average particle diameter means the average particle diameter of an aggregate, when particle | grains are the aggregates of a primary particle. Moreover, when a particle is not spherical, it means the diameter of a circle corresponding to the projected area.

  The refractive index of the particles is preferably 1.45 to 1.70, more preferably 1.45 to 1.65. Note that the refractive index of the particles is measured by measuring the turbidity by dispersing the same amount of particles in a solvent in which the refractive index is changed by changing the mixing ratio of two types of solvents having different refractive indexes. The refractive index of the solvent can be measured by measuring with an Abbe refractometer.

  In addition, the refractive index difference between the resin used for the support and the particles is preferably 0.02 or more and 0.20 or less in order to increase the internal haze using the light scattering effect. A more preferable range of the refractive index difference is 0.05 or more and 0.15 or less.

  The content of the inorganic or organic particles is preferably 1 part by mass to 30 parts by mass with respect to 100 parts by mass of the resin for producing the film base material, and more preferably 5 parts by mass to 25 parts by mass for obtaining the internal haze. Part.

  The particles may be dispersed together with cellulose ester, other additives and an organic solvent at the time of preparing a composition (dope) for producing a film substrate, or may be dispersed alone in a solution. . As a method for dispersing the particles, it is preferable that the particles are preliminarily dispersed in an organic solvent and then finely dispersed by a disperser (high pressure disperser) having a high shearing force.

  As a dope preparation method, it is preferable to disperse particles in a large amount of an organic solvent, merge with a cellulose ester solution, and mix with an in-line mixer to form a dope. In this case, an ultraviolet absorbent may be added to the particle dispersion to form an ultraviolet absorbent liquid.

  In addition, the above plasticizer and ultraviolet absorber may be added together with a solvent in the preparation of a solution composed of cellulose ester or cellulose ester resin and an acrylic resin. It may be added during or after preparation.

(Organic solvent)
When the cellulose ester film is produced by a solution casting method, the dope preferably contains an organic solvent from the viewpoint of film forming property and productivity. Any organic solvent can be used without limitation as long as it dissolves cellulose ester and other additives simultaneously. For example, methylene chloride, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3 , 3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3 , 3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane and the like. Among these organic solvents, methylene chloride, methyl acetate, ethyl acetate, and acetone are preferably used.

  The dope preferably contains 1 to 40% by mass of an alcohol having 1 to 4 carbon atoms in addition to the organic solvent. When the proportion of alcohol in the dope increases, the web gels, facilitating peeling from the metal support, and when the proportion of alcohol is small, the role of promoting dissolution of cellulose esters in non-chlorine organic solvents There is also. Examples of the alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Ethanol is preferred because of the stability of these dopes, the boiling point being relatively low, good drying properties, and no toxicity. The concentration of the cellulose ester in the dope is preferably adjusted to 15 to 40% by mass, and the dope viscosity is preferably adjusted to a range of 10 to 50 Pa · s in order to obtain good film surface quality.

<< second protective film >>
Next, the second protective film will be described. Hereinafter, it is also referred to as a retardation film.

  The second protective film of the present invention is a protective film disposed opposite to the first protective film with respect to the polarizing film, and includes at least a transparent film and a substantially vertically aligned polymerizable liquid crystal compound. Consists of sex layers. In particular, the polymerizable liquid crystal compound is preferably a rod-like liquid crystal compound for an IPS liquid crystal display device.

  The second protective film of the present invention preferably has a film thickness of 20 to 80 μm and preferably has the following characteristics as a retardation value.

0nm ≦ Ro ≦ 330nm
−150 nm ≦ Rt ≦ 150 nm
Ro and Rt are the total of Ro and Rt of the transparent film, the optically anisotropic layer in which the rod-like liquid crystal is vertically aligned and the alignment is fixed, and in some cases, other intermediate layers.

  The retardation value was measured by adjusting the humidity to a wavelength of 590 nm and 23 ° C. and 55% RH using an automatic birefringence meter KOBRA-21ADH (Oji Scientific Instruments).

  In order to obtain the 2nd protective film of this invention, it is preferable to be comprised by the transparent film and vertical alignment liquid crystal layer as described at least below.

  The transparent film of the present invention preferably has the following characteristics.

Transmittance: 80% or more Film thickness: 20-80 μm
0nm ≦ Ro ≦ 330nm
−100 nm ≦ Rt ≦ 340 nm
Ro = (nx−ny) × d
Rt = ((nx + ny) / 2−nz) × d
(Where nx is the refractive index in the slow axis direction in the plane of the transparent film, ny is the refractive index in the direction perpendicular to the slow axis in the plane, nz is the refractive index in the thickness direction, and d is transparent) Represents the thickness (nm) of the film, and the measurement wavelength of the refractive index is 590 nm.
The refractive index can be obtained at a wavelength of 590 nm under an environment of 23 ° C. and 55% RH using, for example, KOBRA-21ADH (Oji Scientific Instruments).

  For the second protective film, the base film described in the first protective film can be used, and among them, a cellulose ester film is particularly preferable.

  Hereinafter, the case where a cellulose-ester film is used as a transparent film is demonstrated.

<Optically anisotropic layer in which rod-like liquid crystal is vertically aligned and fixed in alignment>
The optically anisotropic layer preferably has the following characteristics.

0 ≦ Ro ≦ 10
−500 ≦ Rt ≦ −100
Here, Ro is the in-plane retardation, Rt is the thickness direction retardation (Rt), the main refractive index of the optically anisotropic layer is nx (slow axis), and the refractive index in the direction orthogonal to the main refractive index is When ny is the fast axis, the refractive index in the thickness direction of the layer is nz, and the thickness of the layer is d (nm), Ro = (nx−ny) × d, Rt = (( nx + ny) / 2−nz) × d.

  The optically anisotropic layer of the present invention is obtained by applying a liquid crystal material or a liquid crystal solution directly on the cellulose ester film or on an intermediate layer, drying and heat-treating (also referred to as orientation treatment), ultraviolet curing or thermal polymerization. It is preferably a retardation layer made of rod-like liquid crystal in which liquid crystal alignment is fixed and aligned in the vertical direction (hereinafter, the optically anisotropic layer is also referred to as a retardation layer).

  Here, “orienting in the vertical direction” means that the rod-like liquid crystal is in the range of 70 to 90 ° (the vertical direction is 90 °) with respect to the film surface serving as the support.

  The rod-like liquid crystal may be oriented obliquely or the orientation angle may be gradually changed. Preferably it is the range of 80-90 degrees.

  The optically anisotropic layer of the present invention is a retardation layer made of a rod-like liquid crystal oriented in the vertical direction with Ro in the range of 0 to 10 nm and Rt in the range of −500 to −100 nm. Further, Ro is more preferably in the range of 0 to 5 nm. The phase difference measurement of the layer on which the liquid crystal alignment is fixed on these supports can be measured using AxoScan manufactured by Opto Science Co., Ltd.

  When forming a retardation layer by aligning rod-shaped liquid crystals, an alignment film coated with a vertical alignment agent that aligns so-called liquid crystal materials in the vertical direction is used as an intermediate layer, and the liquid crystal material is vertically aligned and fixed. You can take a method.

  When the liquid crystal material itself is aligned in the vertical direction at the air interface, the alignment regulating force extends to the interface opposite to the air interface, and the alignment film is not particularly necessary, and this is also preferable from the viewpoint of simplifying the configuration. preferable.

  As a specific method for vertically aligning the liquid crystal material, an alignment film composed of a cross-linked product of a block polymer composition containing a (meth) acrylic block polymer described in JP-A-2005-148473 and the like is used. Known methods such as a method of using, a method of using a vertical alignment film described in JP 2005-265889 A, and a method of using an air interface vertical alignment agent can be used.

  In order to make the retardation layer in the above range, it is preferable to control the orientation of the rod-like liquid crystal layer, the film thickness control, the temperature during UV curing, the tilt angle control, and the control of the pretilt angle at the support / air interface.

  The retardation layer is formed by curing a liquid crystal material capable of forming a liquid crystal phase at a predetermined temperature with a predetermined liquid crystal regularity. The upper limit of the temperature showing the liquid crystal phase is not particularly limited as long as the cellulose ester film of the base material is not damaged.

  Specifically, a temperature of 120 ° C. or lower is preferable from the viewpoint of easy control of process temperature and maintenance of dimensional accuracy, and a liquid crystal material that becomes a liquid crystal phase at a temperature of 100 ° C. or lower is preferably used. On the other hand, the lower limit of the temperature showing the liquid crystal phase can be said to be a temperature at which the liquid crystal material can maintain the alignment state when used as a polarizing plate.

  As the liquid crystal material used for the retardation layer, a polymerizable liquid crystal material is preferably used. The polymerizable liquid crystal material can be used by being polymerized by irradiating with predetermined actinic radiation. In the polymerized state, the vertical alignment state is fixed.

  As the polymerizable liquid crystal compound, any of a polymerizable liquid crystal monomer, a polymerizable liquid crystal oligomer, and a polymerizable liquid crystal polymer can be used, and they can be used by mixing with each other.

  Among the above, a polymerizable liquid crystal monomer is preferably used as the polymerizable liquid crystal compound because of its high sensitivity during alignment and easy vertical alignment.

  Specific examples of the polymerizable liquid crystal monomer include a rod-like liquid crystal compound (I) represented by the following general formula (1) and a rod-like liquid crystal compound (II) represented by the following general formula (2). be able to. As the compound (I), two or more compounds included in the general formula (1) can be mixed and used. Similarly, the compound (II) is included in the general formula (2). Two or more kinds of compounds may be mixed and used. In addition, one or more compounds (I) and one or more compounds (II) may be mixed and used.

In the general formula (1) representing the compound (I), R ¹ and R ² each represent hydrogen or a methyl group, but R ¹ and R ² must be both hydrogen because of the wide temperature range showing the liquid crystal phase. preferable.

  X may be hydrogen, chlorine, bromine, iodine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group, or a nitro group, but is preferably chlorine or a methyl group.

  Moreover, a and b which show the chain length of the alkylene group which is a spacer with the (meth) acryloyloxy group of both ends of the molecular chain of a compound (I), and an aromatic ring are respectively arbitrary integers in the range of 2-12. Although it can take, it is preferable that it is the range of 4-10, and it is more preferable that it is the range of 6-9.

  In addition to the above, in the present invention, conventionally known materials can be appropriately selected and used as the polymerizable liquid crystal oligomer and the polymerizable liquid crystal polymer.

  For example, as a polymerizable rod-like liquid crystal compound, Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. Nos. 4,683,327, 5,622,648 and 5,770,107, International Publication No. 95/22586. Pamphlet, 95/24455, 97/00600, 98/23580, 98/52905, JP-A-1-272551, 6-16616, 7-110469 Gazette, 11-80081, JP-A 2001-328773, JP-A 2004-240188, JP-A 2005-99236, JP-A 2005-99237, JP-A 2005-121827, It is possible to use the compounds described in Kaikai 2002-30042. You can.

  As commercially available compounds, UCL-018 (Dainippon Ink Chemical Co., Ltd.), Palio Color LC242 (BASF Co., Ltd.), etc. can be used.

  In the present invention, a photopolymerization initiator is used as necessary in addition to the polymerizable liquid crystal compound. When polymerizing a polymerizable liquid crystal compound by electron beam irradiation, a photopolymerization initiator may not be necessary. However, in the case of curing by, for example, ultraviolet (UV) irradiation, which is generally used, photopolymerization is usually performed. An initiator is used to promote polymerization.

  Photopolymerization initiators include benzyl (also called bibenzoyl), benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoyl benzoic acid, methyl benzoyl benzoate, 4-benzoyl-4'-methyldiphenyl sulfide, benzyl methyl ketal, dimethylamino Methylbenzoate, 2-n-butoxyethyl-4-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3′-dimethyl-4-methoxybenzophenone, methylobenzoylformate, 2-methyl-1- (4 -(Methylthio) phenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 1- (4-dodecylphenyl) -2- Droxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2- Examples include methylpropan-1-one, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, or 1-chloro-4-propoxythioxanthone. it can.

  In general, the addition amount of the photopolymerization initiator is preferably 0.01% to 20%, more preferably 0.1% to 10%, and still more preferably 0.5% to 5%. Can be added to the polymerizable liquid crystal material of the present invention.

  In addition to the photopolymerization initiator, a sensitizer can be added as long as the object of the present invention is not impaired.

  The film thickness of the optically anisotropic layer in the present invention is preferably in the range of 0.1 μm to 10 μm, and more preferably in the range of 0.2 to 5 μm.

  The polymerizable liquid crystal compound is prepared by using a composition for forming an optically anisotropic layer by blending a photopolymerization initiator, a sensitizer, etc., if necessary, and coating it on a substrate. A layer forming layer is formed.

  As a method of forming a layer in which the orientation of liquid crystal is fixed, for example, a method in which a dry film or the like is formed in advance and a layer in which the orientation of liquid crystal is fixed is laminated on a substrate, or a liquid crystal composition is dissolved. Alternatively, it is possible to use a method of melting and coating on a substrate, but in the present invention, a liquid crystal composition is added with a solvent and a coating composition in which other components are dissolved is used. It is preferable to form a layer in which the orientation of the liquid crystal is fixed by coating on the substrate and removing the solvent. This is simple in terms of process as compared with other methods.

  The solvent is not particularly limited as long as it is a solvent capable of dissolving the above-described polymerizable liquid crystal material and the like and does not deteriorate the properties of the transparent resin film. Specifically, benzene, Hydrocarbons such as toluene, xylene, n-butylbenzene, diethylbenzene, tetralin; ethers such as methoxybenzene, 1,2-dimethoxybenzene, diethylene glycol dimethyl ether; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, or 2,4- Ketones such as pentanedione; ethyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, or γ-butyrolactone Amides solvents such as 2-pyrrolidone, N-methyl-2-pyrrolidone, dimethylformamide or dimethylacetamide; chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, tritrichloroethylene, tetrachloroethylene, chlorobenzene, or orthodichlorobenzene Halogen solvents such as t-butyl alcohol, diacetone alcohol, glycerin, monoacetin, ethylene glycol, triethylene glycol, hexylene glycol, ethylene glycol monomethyl ether, ethyl cellosolve, or butyl cellosolve; phenols, One or more of phenols such as parachlorophenol can be used.

  If only a single type of solvent is used, the solubility of the polymerizable liquid crystal material or the like may be insufficient, or the substrate may be eroded as described above. However, this inconvenience can be avoided by using a mixture of two or more solvents.

  Of the above-mentioned solvents, preferred as a single solvent are a hydrocarbon solvent and a glycol monoether acetate solvent, and a preferred mixed solvent is a mixed system of ethers or ketones and glycols. It is.

  The concentration of the solution depends on the solubility of the polymerizable liquid crystal material and the like and the film thickness of the optically anisotropic layer to be produced, but cannot be defined unconditionally, but is usually preferably 1% to 60%, more preferably It is adjusted in the range of 3% to 40%.

  Compounds other than those described above can be added to the composition for forming an optically anisotropic layer used in the present invention within a range not impairing the object of the present invention.

  Examples of compounds that can be added include polyester (meth) acrylate obtained by reacting (meth) acrylic acid with a polyester prepolymer obtained by condensing polyhydric alcohol and monobasic acid or polybasic acid; A polyurethane (meth) acrylate obtained by reacting a compound having two isocyanate groups with each other and then reacting the reaction product with (meth) acrylic acid; bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak Type epoxy resin, polycarboxylic acid polyglycidyl ester, polyol polyglycidyl ether, aliphatic or cycloaliphatic epoxy resin, amine epoxy resin, triphenolmethane type epoxy resin, dihydroxybenzene type epoxy resin and the like (meth) Ak A photopolymerizable compound such as epoxy (meth) acrylate obtained by reacting phosphoric acid, a photopolymerizable liquid crystal compound having an acrylic group or a methacryl group, an onium salt described in JP-A-2007-45993, and a fluorine compound. Acrylate polymers and the like.

  The amount of these compounds added to the composition for forming an optically anisotropic layer of the present invention is selected within a range that does not impair the object of the present invention, and in general, the composition for forming an optically anisotropic layer of the present invention. Is preferably 40% or less, more preferably 20% or less.

  Addition of these compounds improves the curability of the liquid crystal material in the present invention, increases the mechanical strength of the resulting optically anisotropic layer, and improves its stability.

  In addition, a surfactant or the like can be added to the composition for forming an optically anisotropic layer containing a solvent in order to facilitate coating.

  Examples of surfactants that can be added include cationic surfactants such as imidazoline, quaternary ammonium salts, alkylamine oxides and polyamine derivatives; polyoxyethylene-polyoxypropylene condensates, primary or secondary Alcohol ethoxylates, alkylphenol ethoxylates, polyethylene glycol and esters thereof, sodium lauryl sulfate, ammonium lauryl sulfate, lauryl sulfate amines, alkyl-substituted aromatic sulfonates, alkyl phosphates, aliphatic or aromatic sulfonic acid formalin condensates, etc. Anionic surfactants; amphoteric surfactants such as laurylamidopropylbetaine and laurylaminoacetic acid betaine; nonionics such as polyethylene glycol fatty acid esters and polyoxyethylene alkylamine Surfactant: Perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl trimethyl ammonium salt, perfluoroalkyl group / hydrophilic group-containing oligomer, perfluoroalkyl / lipophilic group Fluorosurfactants such as containing oligomer perfluoroalkyl group-containing urethanes.

  The amount of surfactant added depends on the type of surfactant, the type of liquid crystal material, the type of solvent, and the type of alignment film on which the solution is applied. 10 ppm to 10% is preferable, more preferably 100 ppm to 5%, and most preferably 0.1 to 1%.

  As a method of coating the composition for forming an optically anisotropic layer, a spin coating method, a roll coating method, a printing method, a dip pulling method, a die coating method, a casting method, a bar coating method, a blade coating method, a spray coating method, Examples include a gravure coating method, a reverse coating method, and an extrusion coating method.

  As a method for removing the solvent after coating the composition for forming an optically anisotropic layer, for example, air drying, heat removal, or reduced pressure removal, and a combination of these methods are performed. By removing the solvent, a layer in which the alignment of the liquid crystal is fixed is formed.

  In the step of curing the polymerizable liquid crystal material, energy for curing the polymerizable liquid crystal material is given, and thermal energy may be used, but it is usually performed by irradiation with ionizing radiation capable of causing polymerization.

  If necessary, a polymerization initiator may be contained in the polymerizable liquid crystal material. The ionizing radiation is not particularly limited as long as it is a radiation capable of polymerizing the polymerizable liquid crystal material. Usually, ultraviolet light or visible light is used from the viewpoint of the ease of the apparatus, and the wavelength is The light of 150-500 nm is preferable, More preferably, it is 250-450 nm, More preferably, it is an ultraviolet-ray with a wavelength of 300-400 nm.

  In the present invention, a method of performing radical polymerization by irradiating ultraviolet rays (UV) as actinic radiation and generating radicals from the polymerization initiator with ultraviolet rays is preferable. Since the method using UV as the actinic radiation is an already established technique, it can be easily applied to the present invention including the polymerization initiator to be used.

  As a light source for irradiating ultraviolet rays, a low-pressure mercury lamp (sterilization lamp, fluorescent chemical lamp, black light), a high-pressure discharge lamp (high-pressure mercury lamp, metal halide lamp), or a short arc discharge lamp (ultra-high-pressure mercury lamp, xenon) Lamp, mercury xenon lamp) and the like.

  In particular, the use of metal halide lamps, xenon lamps, high-pressure mercury lamps, etc. is recommended. The irradiation intensity may be appropriately adjusted depending on the composition of the polymerizable liquid crystal material used for forming the layer in which the alignment of the liquid crystal is fixed and the amount of the photopolymerization initiator.

  The alignment fixing step by irradiation with actinic radiation may be performed at the processing temperature in the step of forming the optically anisotropic layer forming layer described above, that is, a temperature condition in which the polymerizable liquid crystal material becomes a liquid crystal phase. The temperature may be lower than the temperature at which

(Middle layer)
An intermediate layer may be provided between the optically anisotropic layers in which the transparent film and the rod-shaped liquid crystal are aligned vertically to fix the alignment.

  The intermediate layer is preferably made of a transparent resin. The transparent resin is preferably a binder polymer having a saturated hydrocarbon chain or a polyether chain as a main chain, and more preferably a binder polymer having a saturated hydrocarbon chain as a main chain.

  Particularly preferred is a resin that is cured through a crosslinking reaction or the like by irradiation with active rays such as ultraviolet rays or electron beams, or a mixed composition of a crosslinking agent and a resin having a reactive site.

  Examples of the curable resin include UV curable urethane acrylate resins, UV curable polyester acrylate resins, UV curable epoxy acrylate resins, UV curable polyol acrylate resins, and UV curable epoxy resins. A type acrylate resin is preferably used.

  The UV curable urethane acrylate resin generally includes a product obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer, and further includes 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter, acrylate includes methacrylate). It can be easily obtained by reacting an acrylate monomer having a hydroxyl group such as 2-hydroxypropyl acrylate.

  For example, those described in JP 59-151110 A can be used. For example, a mixture of 100 parts of purple light UV-7510B (manufactured by Nippon Synthetic Chemical Co., Ltd.), Unidic 17-806 (manufactured by Dainippon Ink Co., Ltd.) and 1 part of coronate L (manufactured by Nippon Polyurethane Co., Ltd.) Preferably used.

  Examples of UV curable polyester acrylate resins include those which are easily formed when 2-hydroxyethyl acrylate and 2-hydroxy acrylate monomers are generally reacted with polyester polyols. JP-A-59-151112 Those described in the publication can be used.

  Specific examples of the ultraviolet curable epoxy acrylate resin include an epoxy acrylate as an oligomer, a reactive diluent and a photopolymerization initiator added thereto, and reacted to form an oligomer. Those described in Japanese Patent No. 105738 can be used.

  Specific examples of UV curable polyol acrylate resins include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate, etc. Can be mentioned.

  Specific examples of photopolymerization initiators for these curable resins include benzoin and derivatives thereof, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof. You may use with a photosensitizer.

  In addition, when using an epoxy acrylate photopolymerization initiator, a sensitizer such as n-butylamine, triethylamine, tri-n-butylphosphine can be used.

  The photopolymerization initiator or photosensitizer used in the curable resin composition is 0.1 to 25 parts by mass, preferably 1 to 15 parts by mass with respect to 100 parts by mass of the composition.

  Examples of the mixed composition of the crosslinking agent and the resin having a reactive site according to the present invention include polyvinyl alcohol and glyoxal, gelatin and glyoxal.

  Further, the intermediate layer may contain a fluorine-acrylic copolymer resin. The fluorine-acrylic copolymer resin is a copolymer resin composed of a fluorine monomer and an acrylic monomer, and a block copolymer composed of a fluorine monomer segment and an acrylic monomer segment is particularly preferable.

  Further, the intermediate layer may be two or more layers.

<Method for producing intermediate layer>
For the intermediate layer, a coating composition for forming the intermediate layer containing the retardation increasing agent of the present invention is applied using a known method such as a gravure coater, dip coater, reverse coater, wire bar coater, die coater, and ink jet method. It is preferable that after coating on a support, it is dried by heating and UV-cured.

  The coating amount is suitably 0.1 to 40 μm, preferably 0.5 to 30 μm, as the wet film thickness.

  Moreover, as a dry film thickness, it is an average film thickness of 0.01-1 micrometer, Preferably it is 0.02-0.7 micrometer.

  As the light source for the UV curing treatment, any light source that generates ultraviolet rays can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.

Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 5 to 500 mJ / cm ² , preferably 5 to 150 mJ / cm ² .

  Moreover, when irradiating actinic radiation, it is preferable to carry out while applying tension | tensile_strength in the conveyance direction of a film, More preferably, it is performing applying tension | tensile_strength also in the width direction. The tension to be applied is preferably 30 to 300 N / m.

  The method for applying tension is not particularly limited, and tension may be applied in the transport direction on the back roll, or tension may be applied in the width direction or biaxial direction by a tenter. This makes it possible to obtain a film having further excellent flatness.

  The coating composition for forming the intermediate layer may contain a solvent. Examples of the organic solvent contained in the coating composition include hydrocarbons (toluene, xylene), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol), and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone). , Esters (methyl acetate, ethyl acetate, methyl lactate), glycol ethers, and other organic solvents may be appropriately selected or mixed for use.

  As the organic solvent, propylene glycol monoalkyl ether (1 to 4 carbon atoms of the alkyl group) or propylene glycol monoalkyl ether acetate (1 to 4 carbon atoms of the alkyl group) is preferable. Moreover, as content of an organic solvent, 5-80 mass% is preferable in a coating composition.

"Polarizer"
A polarizing plate using the first protective film and the second protective film of the present invention will be described.

  The polarizing plate can be produced by a general method. The first and second protective films of the present invention are subjected to alkali saponification treatment on the back side, and the treated protective film is immersed and stretched in an iodine solution on at least one surface of the polarizing film, and completely saponified polyvinyl It is preferable to bond using an aqueous alcohol solution. At that time, in the first protective film, the gap holding layer is preferably bonded to the side far from the polarizing film, and in the second protective film, the optically anisotropic layer is preferably bonded to the side far from the polarizing film.

  The polarizing film, which is the main component of the polarizing plate, is an element that transmits only light having a polarization plane in a certain direction. A typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol film. There are ones in which iodine is dyed on a system film and ones in which a dichroic dye is dyed, but it is not limited to this.

  As the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxially stretching or dyed, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound.

  A polarizing film having a thickness of 5 to 30 μm, preferably 8 to 15 μm, is preferably used. On the surface of the polarizing film, one surface of the protective film of the present invention is bonded to form a polarizing plate. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.

<Liquid crystal display device>
By incorporating the polarizing plate of the present invention on the viewing surface side of the liquid crystal display device, the liquid crystal display device of the present invention having various visibility can be produced.

  As the liquid crystal display device, a reflective type, a transmissive type, a transflective type LCD, or a TN type, STN type, OCB type, HAN type, VA type (PVA type, MVA type), or IPS type LCD is preferable. Although it is used, it is particularly preferably used in an IPS liquid crystal ideographic apparatus.

  FIG. 3 is a schematic view of an IPS mode liquid crystal display device according to the present invention.

  A light guide plate, a prism sheet (not shown), and a backlight side polarizing plate L-12 are arranged adjacent to the backlight L-13 from below. The polarizing film L-8 of the backlight side polarizing plate L-12 is sandwiched between the polarizing plate protective film L-7 and the polarizing plate protective film L-9. Next, there is an IPS liquid crystal cell L-6 having a configuration of an electrode side cell glass substrate L-6-2, an IPS type liquid crystal cell L-6-3, and a non-electrode type cell glass substrate L-6-1. There is a polarizing film L-2 constituting the plate L-10, a first protective film L-1 of the present invention, and a second protective film L-11.

  Other polarizing plate protective films L-7 and L-9 are not particularly limited. For example, polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyethylene films, polypropylene films, polycycloolefin films, cellophane, and cellulose. Acetate film, cellulose acetate butyrate film, cellulose acetate phthalate film, cellulose acetate propionate film, cellulose triacetate, film made of cellulose esters such as cellulose nitrate or derivatives thereof, polyvinylidene chloride film, polyvinyl alcohol film, ethylene Vinyl alcohol film, syndiotactic polystyrene film, polycarbonate film , Cycloolefin polymer film (eg, ARTON (manufactured by JSR), ZEONEX, ZEONOR (manufactured by ZEON)), polymethylpentene film, polyetherketone film, polyethersulfone film, polysulfone film, polyetherketoneimide Examples thereof include a film, a polyamide film, an acrylic film, and a polyacrylate film.

  Cellulose ester films such as cellulose acetate propionate film and cellulose triacetate film (TAC film) are commercially available films, such as Konica Minolta Op KONICA MINOLTATAC KC8UX, KC4UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY KC4UY, KC12UR, KC16UR, KC4UE, KC8UE, KC4FR-1, KC4FR-2, etc. are preferably used. In addition, a cycloolefin polymer film, a polycarbonate film, a polyester film, or a polyacrylic film can also be preferably used in terms of transparency, mechanical properties, and lack of optical anisotropy. These resin films may be films formed by a melt casting method or a solution casting method.

  In the case of an IPS mode liquid crystal display device, the polarizing plate protective films 7 and 9 have a retardation value Rt value in the range of -20 to 20 nm, more preferably -10 to 10 nm, and a Ro value of 0 to 10 nm. It is also preferred to use a range of films.

<IPS horizontal electric field switching mode type liquid crystal display device>
By incorporating a polarizing plate using the polarizing plate protective film of the present invention into a commercially available IPS (In Plane Switching) mode type liquid crystal display device, it has excellent visibility, excellent color shift, corner unevenness, and front contrast characteristics. The liquid crystal display device of the present invention can be manufactured.

  The IPS mode of the present invention includes a fringe-field switching (FFS) mode in the present invention, and the polarizing plate of the present invention can be incorporated in the same manner as the IPS mode. A liquid crystal display device can be manufactured.

(IPS mode liquid crystal cell)
The liquid crystal layer of the liquid crystal panel in the IPS mode type liquid crystal display device is homogeneously aligned parallel to the substrate surface in the initial state, and the director of the liquid crystal layer is parallel to the electrode wiring direction when no voltage is applied. The direction of the director of the liquid crystal layer shifts to a direction perpendicular to the electrode wiring direction when a voltage is applied, and the director direction of the liquid crystal layer is the direction of the director when no voltage is applied. When tilted in the direction of 45 ° electrode wiring, the liquid crystal layer when the voltage is applied rotates the azimuth angle of the polarization by 90 ° like a half-wave plate, and the transmission axis of the output side deflection plate and the polarization The azimuth angles of the two coincide with each other to display white.

  In general, the thickness of the liquid crystal layer is constant, but since it is driven by a lateral electric field, it is considered that a slight unevenness in the thickness of the liquid crystal layer can increase the response speed to switching. Even if the thickness of the layer is not constant, the effect can be maximized.

  In this invention, there is little influence with respect to the change of the thickness of a liquid crystal layer. The thickness of the liquid crystal layer capable of greatly exerting the effect in the present invention is 2 to 6 μm, and preferably 3 to 5.5 μm.

  The liquid crystal display device of the present invention is used for a large liquid crystal television. As a screen size, it can be used for 17 or more types, preferably 26 to 100 types.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1
(Production of cellulose ester film 2 which is a transparent film of the second protective film)
<Synthesis of cellulose ester>
With reference to Example B of JP-T-6-501040, the amount of propionic acid and acetic acid was adjusted to synthesize cellulose ester A having an acetyl group substitution degree of 1.6 and a propionyl group substitution degree of 0.9. .

  The substitution degree of the obtained cellulose ester was calculated based on ASTM-D817-96.

<Preparation of cellulose ester film 2 by melting method>
(Synthesis of acrylic polymer X1)
Bulk polymerization was performed by the polymerization method described in JP-A No. 2000-344823. That is, the contents were heated to 70 ° C. while introducing the following methyl acrylate and ruthenocene into a flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer, an inlet, and a reflux condenser.

  Next, half of the following β-mercaptopropionic acid which had been sufficiently purged with nitrogen gas was added to the flask under stirring. After the addition of β-mercaptopropionic acid, the contents in the stirring flask were maintained at 70 ° C. and polymerization was carried out for 2 hours.

  Further, after adding the other half of the β-mercaptopropionic acid substituted with nitrogen gas, the temperature of the content under stirring was maintained at 70 ° C., and polymerization was carried out for 4 hours. The temperature of the reaction product was returned to room temperature, and 20 parts by mass of a 5% by mass benzoquinone tetrahydrofuran solution was added to the reaction product to stop the polymerization.

  While gradually heating the polymer to 80 ° C. under reduced pressure with an evaporator, the tetrahydrofuran, residual monomer and residual thiol compound were removed to obtain an acrylic polymer X1. The weight average molecular weight Mw was 1000.

Methyl acrylate 100 parts by weight Ruthenocene (metal catalyst) 0.05 parts by weight β-mercaptopropionic acid 12 parts by weight 100 parts by weight of cellulose ester A dried at 80 ° C. for 6 hours (water content 200 ppm), Monopet SB (sugar ester compound) : Daiichi Kogyo Seiyaku Co., Ltd.) 9 parts by mass, acrylic polymer X1 3 parts by mass, UV absorber LA-31 (manufactured by ADEKA) 1.05 parts by mass, Irganox 1010 (manufactured by Ciba Japan Co., Ltd.) 0.5 parts by mass, Adeka Stub PEP-36 (manufactured by ADEKA) 0.08 parts by mass, Sumilizer GS (manufactured by Sumitomo Chemical Co., Ltd.) 0.2 parts by mass, Seahoster KEP-30 (manufactured by Nippon Shokubai Co., Ltd.) 0.1 parts by mass was further dried with mixing at 80 ° C. and 1 Torr for 3 hours with a vacuum nauter mixer.

  The obtained mixture was melt-mixed at 235 ° C. using a twin-screw extruder and pelletized. The cellulose ester film was produced by the production apparatus shown in FIG. Pellets (water content 50 ppm) were melt extruded from a T die onto a first cooling roll having a surface temperature of 100 ° C. at a melting temperature of 245 ° C. using a single-screw extruder, with an initial film thickness of 128 μm and a width of 1.0 m. A cast film of 35 m / min was obtained.

  At this time, the film was pressed on the first cooling roll with an elastic touch roll having a 2 mm thick metal surface.

  The obtained film was first stretched at 195 ° C. in the film-forming direction at 60% in the film-forming direction at a stretching speed of 1000% / min by a stretching machine using a roll peripheral speed difference to obtain a cellulose ester film 2 having a film thickness of 40 μm.

  At this time, in the width direction, after stretching in the film forming direction, a preheating zone, a stretching zone, a holding zone, and a cooling zone (a neutral zone for ensuring thermal insulation between the zones is also provided between the zones). In a stretching zone at a temperature of 165 ° C., and then cooled to 30 ° C., released from the clip, and the clip gripping portion was cut off to obtain a cellulose ester film 2. The retardation of the cellulose ester film 2 was Ro = 71 nm and Rt = 190 nm. The retardation is a value measured at a wavelength of 590 nm using an automatic birefringence meter KOBRA-21ADH (Oji Scientific Instruments) after humidity adjustment to 23 ° C. and 55% RH. Moreover, the retardation result described in the Example is a value measured under the above conditions.

(Preparation of retardation film 1)
The cellulose ester film 2 produced above was cut to a width of 800 mm and knurled, then an intermediate layer was provided by the following procedure, then an optically anisotropic layer was provided on the intermediate layer, and a retardation film 1 was produced. .

The cellulose ester film 2 cut to a width of 800 mm was subjected to a knurling process having a width of 1 cm and an average height of 10 μm at both ends, and was wound up again. On the cellulose ester fill, the following intermediate layer coating solution was applied by die coating after corona discharge, dried at 80 ° C. for 30 seconds, and then cured by irradiation with ultraviolet rays at 120 mJ / cm ² and an illuminance of 200 mW / cm ² . The film thickness of the intermediate layer after curing was 1.5 μm.

  Next, the following optically anisotropic layer coating solution was applied by die coating to a thickness of 8 μm on this intermediate layer.

After coating, the rod-shaped liquid crystal compound was aligned by heating at 100 ° C. for 2 minutes. Next, the film in which the rod-like liquid crystal compound was aligned was cured by irradiation at an oxygen concentration of 0.2%, a temperature of 28 ° C. at 250 mJ / cm ² , and an illuminance of 300 mW / cm ² to obtain a retardation film 1. The thickness of the optically anisotropic layer was 1.2 μm. The retardation of the retardation film 1 as a whole was 71 nm for Ro and -11 nm for Rt.

(Interlayer coating solution)
25 parts by mass of polyester acrylate (Laromar LR8800 manufactured by BASF Japan Ltd.)
Propylene glycol monomethyl ether 290 parts by mass Isopropyl alcohol 685 parts by mass Photopolymerization initiator (Irgacure 184, manufactured by Ciba Japan Co., Ltd.) 0.05 parts by mass (Coating liquid for optically anisotropic layer)
UV-polymerizable liquid crystal material 20 parts by mass (UCL-018 manufactured by Dainippon Ink & Chemicals, Inc.)
Propylene glycol monomethyl ether 80 parts by mass Hindered amine (LS-765, Sankyo Lifetech Co., Ltd.) 0.02 parts by mass Sensitizer (Kayacure DETX, Nippon Kayaku Co., Ltd.) 0.10 parts by mass The following air interface side Vertical alignment agent 1 0.01 parts by mass

<Preparation of cellulose ester film 3>
(Dope composition A)
・ Triacetyl cellulose (acetylation degree 61.0%) 85 mass parts ・ 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) bezotriazole
1.5 parts by mass-Methyl methacrylate-2-hydroxyethyl acrylate copolymer 8 parts by mass (80/20 (mass ratio)) Mw; 8000
-Methyl acrylate polymer (*) Mw; 1000 5 parts by mass-Methylene chloride 475 parts by mass-Ethanol 50 parts by mass (*) A methyl acrylate monomer was polymerized by the polymerization method described in Example 3 of JP-A No. 2000-128911. , Mw1000, Mn700 polymer was obtained. The reaction product had a hydroxyl value (OHV; mg / g KOH) of 50.

(Matting agent solution composition)
-Silica particle dispersion with an average particle size of 16 nm 11.0 parts by mass-Methylene chloride (first solvent) 76.1 parts by mass-Ethanol (second solvent) 3.5 parts by mass-Acetylpropionyl cellulose (acetyl substitution degree 2. 06, propionyl substitution degree 0.79) 1.9 parts by mass (Preparation of matting agent solution)
20 parts by mass of silica particles having an average particle diameter of 16 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) and 80 parts by mass of methanol were mixed well for 30 minutes to obtain a silica particle dispersion. This dispersion was put into a disperser together with the following composition, and further stirred for 30 minutes or more to dissolve each component to prepare a matting agent solution.

  The dope composition A having the above formulation was put into a sealed container, heated to 70 ° C., and stirred to completely dissolve cellulose triacetate (TAC) to obtain a dope. The time required for dissolution was 4 hours. After the dope composition A is filtered, 6.5 parts by weight of the matting agent solution is mixed, and the mixture is uniformly cast on a stainless steel band support at a dope temperature of 35 ° C. and a temperature of 22 ° C. did. The temperature of the stainless steel band support was 20 ° C.

  Then, after making it dry to the range which can be peeled, dope was peeled from the stainless steel band support body. The residual solvent amount of the dope at this time was 25% by mass. The time required from casting the dope to peeling was 3 minutes. Peel from the stainless steel band support with a tension of 10 kg / m, stretch 2% in the width direction with a tenter at 140 ° C, and then finish drying in a drying zone at 120 ° C and 135 ° C while transporting with many rolls. Then, a knurling process having a width of 10 mm and a height of 10 μm was applied to both ends of the film, and the cellulose ester film 3 having a thickness of 40 μm was wound up. The winding tension was an initial tension of 10 kg / m and a final winding tension of 8 kg / m. The film width was 1500 mm and the winding length was 500 m.

  The retardation was Ro = 0.5 nm and Rt = −1 nm.

(Preparation of retardation film 2)
The retardation film 2 was produced with reference to the examples of JP-A No. 2004-4642.

By stretching the polycarbonate film, a retardation film 2 having a thickness of 65 μm, an in-plane retardation R ₀ of 260 nm, and Nz = 0.5 was produced.

<Preparation of film 1 having a void retaining layer which is the first protective film>
(Manufacture of quartz master mold)
A mold was produced with reference to the examples in Japanese Patent Application Laid-Open No. 2008-176076.

  A resist layer was applied on a quartz substrate so as to have a thickness of 150 nm, and a latent image of a quasi-hexagonal lattice pattern was formed on the resist layer using the exposure apparatus shown in FIG. 5 of Japanese Patent Application Laid-Open No. 2008-176076. . The wavelength of the laser beam was 266 nm, and the laser power was 0.50 mJ / m. The laser light was modulated into a sine waveform whose amplitude fluctuates about ± 10% non-periodically in the electro-optic modulator and then guided to the modulation optical system. Further, the irradiation period of the laser beam on the resist layer was changed for each track. Thereafter, the resist layer was developed to produce a quasi-hexagonal lattice-shaped resist pattern. An alkaline developer was used as the developer.

  Next, a process of removing the resist pattern by oxygen ashing to widen the opening diameter and a process of etching the quartz substrate by plasma etching in a fluorine-based gas atmosphere are repeated, which is schematically shown in FIG. 4C of Japanese Patent Laid-Open No. 2008-176076. A quartz master mold having the irregularities shown in FIG. Ashing and etching are: (1) oxygen ashing 4 seconds, fluorine-based gas etching 2 minutes, (2) oxygen ashing 4 seconds, fluorine-based gas etching 2 minutes, (3) oxygen ashing 4 seconds, fluorine-based gas etching 2 minutes, (4) 4. Oxygen ashing 4 seconds, fluorine gas etching 2 minutes, (5) Oxygen ashing 4 seconds, fluorine gas etching 4 minutes, (6) Oxygen ashing 4 seconds, fluorine gas etching 6 minutes, process (1) to It carried out sequentially in the order of (6). Further, Ra of the quartz master mold was 250 nm as measured using an AFM (atomic force microscope).

<Preparation of Cellulose Ester Film 1 that is a Base Film of the First Protective Film>
(Dope solution composition 1)
The following materials were sequentially put into a sealed container, the temperature in the container was raised from 20 ° C. to 80 ° C., and the mixture was stirred for 3 hours while maintaining the temperature at 80 ° C. to completely dissolve the cellulose ester. . The silicon oxide fine particles were added dispersed in a solution of a solvent to be added in advance and a small amount of cellulose ester. This dope was filtered using filter paper (Azumi filter paper No. 244, manufactured by Azumi Filter Paper Co., Ltd.) to obtain a dope solution composition 1.

Cellulose triacetate (acetyl group substitution degree 2.95) 100 parts by weight Trimethylolpropane tribenzoate 5 parts by weight Ethylphthalylethyl glycolate 5 parts by weight Fine particles of silicon oxide 0.2 parts by weight (Aerosil R972V, manufactured by Nippon Aerosil Co., Ltd.)
Tinuvin 109 (manufactured by Ciba Japan) 1 part by mass Tinuvin 171 (manufactured by Ciba Japan) 1 part by mass Methylene chloride 300 parts by mass Ethanol 40 parts by mass Butanol 5 parts by mass Next, the obtained dope composition 1 was subjected to temperature. A web was formed by passing through a casting die kept at 35 ° C. and casting on a support made of stainless steel endless belt and having a temperature of 35 ° C. Next, the web was dried on the support, and the web was peeled from the support with a peeling roll when the residual solvent amount of the web reached 80% by mass.

  The web after peeling is transported while being dried with 90 ° C drying air in a transport drying process using a plurality of rolls arranged on the top and bottom, and then grips both ends of the web with a tenter and then stretches in the width direction at a temperature of 130 ° C. The film was stretched to 1.1 times the previous size. After stretching with a tenter, the web was dried with a drying air at a temperature of 135 ° C. in a transport drying process using a plurality of rolls arranged vertically. After heat-treating for 15 minutes in an atmosphere with an atmosphere substitution rate of 15 (times / hour) in the drying step, the product was cooled to room temperature, and the length was 1.5 m, the film thickness was 40 μm, the length was 3000 m, and the refractive index was 1.49. Cellulose ester film 1 was produced. Further, the film was wound by applying a knurling process at both ends to a width of 2 cm and an average height of 20 μm. The draw ratio in the web conveyance direction immediately after peeling calculated from the rotational speed of the stainless steel band support and the operating speed of the tenter was 1.2 times.

<Atmosphere replacement rate>
The atmosphere replacement rate is defined as the atmosphere of the heat treatment chamber per unit time determined by the following formula when the atmosphere capacity of the heat treatment chamber is V (m ³ ) and the fresh air flow rate is FA (m ³ / hr). The number of replacements with -air. “Fresh-air” means that the wind blown into the heat treatment chamber is not a wind that is recycled and reused, and it means a fresh wind that does not contain volatilized solvent or plasticizer or has been removed. Yes.

Atmosphere replacement rate = FA / V (times / hour)
(Preparation of film 1 having a void retaining layer)
The cellulose ester film 1 produced above was cut to a width of 800 mm and knurled, and then a void retaining layer was provided on the hard coat layer by the following procedure to produce a film 1 having a void retaining layer.

The cellulose ester film 1 cut to a width of 800 mm was subjected to a knurling process having a width of 1 cm and an average height of 18 μm at both ends, and was wound up again. On the cellulose ester fill 1, the following hard coat layer composition 1 is filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a hard coat layer coating solution, which is applied using a micro gravure coater, It dried on 80 degreeC and 60 second conditions. Next, the quartz master-type concavo-convex surface having the concavo-convexity on the prepared surface and the hard coat layer were brought into close contact with the uncured hard coat layer after drying, and pressed with a roll so as to be on the plate side. In this state, from the cellulose ester film 1 side, an ultraviolet lamp is used, the illuminance of the irradiated part is 300 mW / cm ² , the irradiation amount is 0.3 J / cm ² , the coating layer is cured, and the mold having unevenness is removed. From the coat layer side, an ultraviolet lamp was used to irradiate the irradiated portion with an illuminance of 300 mW / cm ² and an irradiation amount of 0.3 J / cm ² to prepare a film 1 having a void holding layer with a dry film thickness of 8 μm.

-Measurement of porosity As a result of measuring the space | gap holding layer using AFM (atomic force microscope), Ra was 330 nm. In addition, a cross section of the void retaining layer was cut out using a microtome, observed with a transmission electron microscope (TEM), and the porosity was determined from the area of the concave portion from Ra obtained from AFM and the ratio of the cross-sectional profile of the layer obtained by TEM. Was measured. As a result, the porosity of the void retaining layer was 36%.

  The period Pmax at the top of the fine concavo-convex structure was 250 nm, and Pmax ≦ 380 nm.

(Hard coat layer composition 1)
The following materials were stirred and mixed to obtain hard coat layer composition 1.

Radical polymerizable compound: Pentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) 180 parts by mass Irgacure 184 (photopolymerization initiator, manufactured by Ciba Japan Co., Ltd.) 9 parts by mass Seahoster KEP-50 (manufactured by Nippon Shokubai Co., Ltd.) 9 Mass part Polyether-modified silicone compound (trade name; KF-355A, manufactured by Shin-Etsu Chemical Co., Ltd.) 9 parts by mass Propylene glycol monomethyl ether 10 parts by mass Ethyl acetate 80 parts by mass Methyl ethyl ketone 100 parts by mass (film 2 having a void retaining layer 7)
First, by changing the conditions of oxygen ashing and fluorine-based gas etching so that the porosity of the film having a void retaining layer is as shown in Table 1, quartz master molds having irregularities with different depths of depression were produced. Next, films 2 to 7 having a void holding layer were produced in the same manner as the production of the film 1 having a void holding layer, except that the produced quartz master mold was used.

(Preparation of film 8 having a void retaining layer)
First, the transparent protective film 1 was produced with reference to the Example of Unexamined-Japanese-Patent No. 2004-4642.

(Preparation of transparent protective film 1)
75 parts by mass of a copolymer comprising isobutene and N-methylmaleimide (N-methylmaleimide content 50 mol%) and 25 parts by mass of an acrylonitrile-styrene copolymer having an acrylonitrile content of 28% by mass are methylene chloride To obtain a solution having a solid concentration of 15% by mass. This solution was cast on a polyethylene terephthalate film, allowed to stand at room temperature for 60 minutes, and then peeled off from the film. After drying at 100 ° C. for 10 minutes, the film was dried at 140 ° C. for 10 minutes and further at 160 ° C. for 30 minutes to obtain a transparent protective film 1 having a thickness of 100 μm. The retardation was Ro = 4 nm and Rt = 4 nm.

  The produced transparent protective film 1 was cut to a width of 800 mm, a void retaining layer was provided on the hard coat layer, and a film 8 having a void retaining layer was produced. On the transparent protective film 1 cut to a width of 800 mm, the hard coat layer composition 1 is applied and dried, and then the quartz master mold having the unevenness used in the production of the film 3 having the void holding layer is used. Then, a void retaining layer was provided and cured in the same manner as the film 3 having the void retaining layer, and a film 8 having a void retaining layer having a dry film thickness of 8 μm was produced. In addition, the porosity was 78% as a result of measuring by the method similar to the film 1 which has a space | gap holding layer.

<Preparation of Polarizing Plate 101>
(Alkaline saponification treatment)
A retardation film 1 having a peelable protective film (PET) attached to an optically anisotropic layer and a film 1 having a void holding layer protected by attaching a peelable protective film (PET) to a gap layer are shown below. Alkaline saponification was carried out under the conditions described. Further, after the alkali saponification treatment, the protective film of the retardation film 1 and the film 1 having the void retaining layer was peeled off and bonded to the polarizing film as described below to produce the polarizing plate 101.

Saponification step 2.5M-NaOH 50 ° C. 90 seconds Water washing step Water 30 ° C. 45 seconds Neutralization step 10 parts HCl 30 ° C. 45 seconds Water washing step Water 30 ° C. 45 seconds Water treatment, neutralization, water washing in this order And then dried at 80 ° C.

<Preparation and bonding of polarizing film>
A 120 μm-thick long roll polyvinyl alcohol film is immersed in 100 parts by mass of an aqueous solution containing 1 part by mass of iodine and 4 parts by mass of boric acid, and stretched 6 times at 50 ° C. in the film forming direction to form the polarizing film L-2. Produced.

  Next, using a polyvinyl alcohol adhesive, film 1 having a void retaining layer saponified on one side of the polarizing film so that the transmission axis of polarizing film L-2 and the in-plane slow axis of the film are parallel to each other A laminated polarizing plate 101 was produced so that the surface opposite to the void layer and the retardation film 1 were combined as shown in FIG.

<Production of Polarizing Plates 102 to 107>
Polarizers 102 to 107 were produced in the same manner except that the film 1 having the void retaining layer was changed to the films 2 to 7 having the void retaining layer in the production of the polarizing plate 101.

<Preparation of Polarizing Plate 108>
The gap layer of the film 8 having a gap holding layer on one side of the polarizing film using an adhesive so that the transmission axis of the polarizing film L-2 produced by the polarizing plate 101 and the in-plane slow axis of the film are parallel to each other; Stuck the opposite side. Next, the retardation film 2 was also bonded using an adhesive so as to have the combination shown in FIG.

<Production of Liquid Crystal Display Device 501>
The polarizing plate 101 of the Matsushita Electric 26-inch liquid crystal television, TH-26LX60 liquid crystal panel is peeled off, and the produced polarizing plate 101 is formed on the viewing-side polarizing plate (L-10) as shown in FIG. Liquid crystal cell glass L-6-1 was bonded using a 5 μm thick adhesive. Further, on the backlight side, a cellulose ester film 3 and a polarizing plate 101 in which the cellulose ester film 1 and the polarizing film L-8 bonded in the configuration as shown in FIG. A liquid crystal panel 401 was prepared by pasting the liquid crystal cell glass L-6-2 using the above adhesive.

  Next, the liquid crystal panel 401 was stored in a high-temperature thermo at 90 ° C. for 500 hours and subjected to heat treatment. The heat-treated liquid crystal panel 401 was set on a liquid crystal television, and a liquid crystal display device 501 was manufactured.

<Production of liquid crystal display devices 502 to 508>
Liquid crystal panels 402 to 408 were produced in the same manner except that the polarizing plate (L-10) on the viewing side of the liquid crystal display device 501 was changed to the polarizing plates 102 to 108. The liquid crystal panels 402 to 408 were similarly heat-treated and set on a liquid crystal television to produce liquid crystal display devices 502 to 508.

  Next, the following evaluation was performed on the manufactured liquid crystal display devices 501 to 508.

  The backlights of the liquid crystal display devices 501 to 508 were turned on and left in a black display state for 500 hours, and the occurrence intensity of unevenness after being left and the light leakage were evaluated according to the following criteria.

[Evaluation of unevenness]
The intensity of unevenness was visually observed and evaluated according to the following criteria.

Situation evaluation No occurrence of unevenness ◎
Weak cloudy unevenness ○
Strong unevenness occurs at the four corners △
Strong unevenness at the four corners and cloudy unevenness on the entire surface ×
[Light leakage evaluation]
Light leakage was evaluated by observing from an oblique direction of 70 °.

Situation evaluation There was very little light leakage.
Although there is a slight light leak, there is no problem in terms of actual damage ○
Some light leakage is observed △
Light leakage is observed on the entire surface ×
The obtained results are shown in Table 1.

  As can be seen from the results of Table 1, a layer having a polymerizable liquid crystal compound substantially vertically aligned on the optically anisotropic layer and having a void holding layer of the first protective film has a porosity of 30% or more. If so, it can be seen that an excellent effect is exhibited against unevenness after heat resistance test and light leakage from an oblique direction. In particular, the film having the void retaining layer exhibits particularly excellent effects on unevenness and light leakage from an oblique direction under the condition where the void ratio is 50% or more and 90% or less.

Example 2
(Preparation of film 9 having a void retaining layer)
In the production of the film 3 having a void retaining layer, a film 9 having a void retaining layer was similarly produced except that the hard coat layer composition 1 was changed to the hard coat layer composition 2.

  The following materials were stirred and mixed to obtain hard coat layer composition 2.

(Hard coat composition 2)
Cationic polymerizable compound: [1- (3-ethyl-3-oxetanyl) methyl] ether
170 parts by mass Cationic polymerizable compound: fluorine-containing epoxy compound 1 10 parts by mass (photocation polymerization initiator)
4-Methylphenyl [4- (1-methylethyl) phenyl] iodonium tetrakis (pentafluorophenyl) borate 6 parts by mass (Lordsil 2074, manufactured by Rhodia Japan Ltd.)
Seahoster KEP-50 (manufactured by Nippon Shokubai Co., Ltd.) 9 parts by mass Polyether-modified silicone compound (trade name; KF-355A, manufactured by Shin-Etsu Chemical Co., Ltd.) 9 parts by mass Propylene glycol monomethyl ether 10 parts by mass Ethyl acetate 80 parts by mass Methyl ethyl ketone 100 Mass parts <Preparation of fluorine-containing epoxy compound 1>
81.03 g of 1,3-dihydroxyhexafluoroisopropylbenzene and 185 g of epichlorohydrin were mixed, 16.27 g of sodium hydroxide and 40 ml of water were added, and the mixture was heated to reflux with stirring.

  After reacting at 130 ° C. for 3 hours, the mixture was naturally cooled, and the produced sodium chloride was removed by suction filtration. The obtained filtrate was extracted with chloroform-water, and the organic layer was dried, filtered and concentrated to obtain 95.7 g of fluorine-containing epoxy compound 1.

<Production of Liquid Crystal Display Devices 509 and 510>
(Preparation of polarizing plate 109)
A polarizing plate 109 was produced in the same manner as the polarizing plate 101 except that the film 9 having a void holding layer was used.

(Production of liquid crystal panel 409)
A liquid crystal panel 409 was produced in the same manner as in the production of the liquid crystal panel 401 except that the produced polarizing plate 109 was used as the viewing side polarizing plate (L-10).

  Next, the liquid crystal panel 409 and the liquid crystal panel 403 manufactured in Example 1 were stored for 750 hours in a high-temperature thermo at 90 ° C. and subjected to heat treatment. The heat-treated liquid crystal panels 409 and 403 were respectively set on a liquid crystal television.

(Production of liquid crystal display devices 509 and 510)
A liquid crystal display device using the liquid crystal panel 409 which was subjected to heat treatment for 750 hours was designated as 509, and a liquid crystal display device using the liquid crystal panel 403 which was subjected to heat treatment for 750 hours was designated as 510. Next, the following evaluation was performed on the liquid crystal display devices 509 and 510 manufactured as described above.

[Evaluation of unevenness and light leakage]
The produced liquid crystal display devices 509 and 510 were evaluated in the same manner as in Example 1 except that the standing time was changed to 750 hours. The obtained results are shown in Table 2.

  As can be seen from the results in Table 2, after the more severe durability test, by forming the void holding layer of the first protective film with a cationic polymerizable compound, particularly excellent unevenness and light leakage from an oblique direction. It turns out that an effect is demonstrated.

It is a perspective view which shows typically an example of the fine concavo-convex structure body produced by this invention. It is an example of the shape of a fine concavo-convex structure. 1 is a schematic view of a liquid crystal display device according to a preferred embodiment of the present invention. It is a general | schematic flow sheet which shows one embodiment of the apparatus which enforces the manufacturing method of the protective film which concerns on this invention.

Explanation of symbols

L-1 First protective film (film having a void layer)
L-2, L-8 Polarizing film L-3 Transparent film (cellulose ester film 2)
L-4 Intermediate layer L-5 Optically anisotropic layer in which rod-like liquid crystal is vertically aligned and fixed in alignment L-6 IPS liquid crystal cell L-6-1 Non-electrode side cell glass substrate L-6-2 Electrode Side cell glass substrate L-6-3 IPS liquid crystal cell L-7 Polarizing plate protective film (cellulose ester film 3)
L-9 Polarizing plate protective film (cellulose ester film 1)
L-10 1st polarizing plate (viewing side polarizing plate)
L-11 Second protective film (retardation film)
L-12 Second polarizing plate (backlight side polarizing plate)
L-13 Backlight 1 Extruder 2 Filter 3 Static mixer 4 Casting die 5 Rotating support (first cooling roll)
6 Nipping pressure rotating body (touch roll)
7 Rotating support (second cooling roll)
8 Rotating support (3rd cooling roll)
9, 11, 13, 14, 15 Transport roll 10 Cellulose ester film 16 Winding device

Claims (7)

In a polarizing plate in which at least a first protective film, a polarizing film, and a second protective film are laminated in this order, the second protective film comprises at least a transparent film and a polymerizable liquid crystal compound that is substantially vertically aligned. A polarizing plate comprising an optically anisotropic layer including the first protective film and a void-holding layer having a porosity of at least 30% on the side far from the polarizing film. The polarizing plate according to claim 1, wherein the gap retaining layer has a fine concavo-convex structure, and a period Pmax at the top of the fine concavo-convex structure is 380 nm or less. The polarizing plate according to claim 2, wherein an outer peripheral surface of the fine concavo-convex structure has a cone shape having an inclination from the top to the bottom. The polarizing plate according to claim 3, wherein the cone shape is an elliptical cone shape or an elliptical truncated cone shape. The polarizing plate according to claim 1, wherein the void retaining layer contains a cationic polymerization compound. A liquid crystal display device using the polarizing plate according to claim 1 on at least one surface of a liquid crystal cell. An IPS (in-plane switching) mode liquid crystal display, wherein the polarizing plate according to any one of claims 1 to 5 is used on at least one surface of an IPS (in-plane switching) mode liquid crystal cell. apparatus.

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