JP2006251294A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device of which the light leakage on the peripheral region is drastically reduced even when the display device is used for a large screen television. <P>SOLUTION: In the liquid crystal display device which has at least a sheet of polarizing plate having: a surface protective film 2 for the polarizing plate; a polarizer 1; and an optical retardation film 5, and a liquid crystal cell 6, the liquid crystal display device is characterized by disposing the polarizing plate so as to place its retardation film side on the liquid crystal cell side, having a position fixing-holding plate stuck to the surface protective film for the polarizing plate directly or across another layer, and disposing the polarizing plate so as not to make its optical retardation film side be stuck to the liquid crystal cell. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device in which peripheral light leakage is significantly reduced even in a large screen TV.

  In general, a polarizing plate used for forming a liquid crystal image display device is a polarizing plate made of triacetyl cellulose (also called TAC) on a polarizer made of polyvinyl alcohol that is usually uniaxially stretched with a dichroic dye having a polarizing function. It is manufactured by bonding two protective films for plates from both sides via an adhesive layer. Since the polarizing plate is used for a display, it has excellent optical characteristics, and it must also have heat resistance from the production environment and use environment. Furthermore, the conventional polarizing plate has a three-layer structure as described above, and is poor in dimensional stability due to its material characteristics. In particular, under a high temperature or high temperature and high humidity environment, the dimensional change due to shrinkage or swelling is large. The stress generated with the dimensional change cannot be absorbed or relaxed by the pressure-sensitive adhesive layer.

  That is, the upper TAC film is likely to shrink or swell due to humidity or heat, but the lower TAC film is firmly attached to the liquid crystal cell via the adhesive layer, and the adhesive layer is capable of following expansion and contraction. Therefore, shrinkage and swelling hardly occur due to humidity and heat. As a result, when light passes from the lower TAC film to the upper TAC film, the light does not advance linearly, and an unfavorable situation such as a so-called white spot phenomenon occurs. This phenomenon was particularly noticeable when the liquid crystal display element was enlarged. In order to solve such a problem, conventionally, a plasticizer is added to the pressure-sensitive adhesive to moderately soften and impart stress relaxation properties. However, in the pressure-sensitive adhesive containing a plasticizer, there are problems that the plasticizer may bleed out or contaminate the adherend when the polarizing plate is peeled off.

Therefore, a polarizing plate with an adhesive layer provided with a silicone adhesive layer as an adhesive layer (see, for example, Patent Document 1), and (A) a (meth) acrylic acid ester system having a mass average molecular weight of 1 million or more. (B) 5-100 mass parts of (meth) acrylic acid ester oligomers having a mass average molecular weight of 1,000 to 10,000 and (C) a bifunctional crosslinking agent per 100 mass parts of the copolymer The pressure-sensitive adhesive composition containing 0.001 to 50 parts by mass of the crosslinking agent component, the pressure-sensitive adhesive sheet having a layer made of the pressure-sensitive adhesive composition on at least one side of the base sheet, and the pressure-sensitive adhesive on at least one side of the sheet-like optical member An adhesive optical member provided with a layer made of an agent composition has been disclosed (for example, see Patent Document 2), but the effect was not sufficient.
JP 2001-194551 A (Claims) JP 2001-335767 A (Claims)

  An object of the present invention is to provide a liquid crystal display device in which peripheral light leakage is remarkably reduced even in a large screen TV.

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

(Claim 1)
In a liquid crystal display device having at least one polarizing plate having a surface polarizing plate protective film, a polarizer, and a retardation film, and a liquid crystal cell, the polarizing film is disposed such that the retardation film side is the liquid crystal cell side, A liquid crystal display device, wherein a position fixing holding plate is attached to a surface protective film of a polarizing plate directly or via another layer, and the retardation film side is not attached to a liquid crystal cell.

(Claim 2)
The liquid crystal display device according to claim 1, wherein the position fixing holding plate is a front plate or a light diffusion plate.

(Claim 3)
The in-plane retardation value Ro of the support represented by the following formulas (i) and (ii) and the thickness direction retardation value Rt of the support satisfy the following ranges. 3. The liquid crystal display device according to 1 or 2.

20 (nm) ≦ Ro ≦ 300 (nm)
−100 (nm) ≦ Rt ≦ 400 (nm)
Formula (i) Ro = (nx−ny) × d
Formula (ii) Rt = {(nx + ny) / 2−nz} × d
(Where nx is the refractive index in the slow axis direction in the support surface, ny is the refractive index in the fast axis direction in the support surface, nz is the refractive index in the thickness direction of the support, and d Represents the thickness (nm) of the support.)
(Claim 4)
The liquid crystal display device according to claim 1, wherein the retardation film is a cellulose ester film or a cyclic olefin-based resin film.

(Claim 5)
The liquid crystal display device according to claim 1, further comprising a fluid medium layer between the retardation film and the liquid crystal cell.

(Claim 6)
The liquid crystal display according to claim 1, wherein the position fixing holding plate is formed of at least one selected from a cyclic olefin resin, an acrylic resin, a polyester, and a glass plate. apparatus.

(Claim 7)
The liquid crystal display device according to claim 1, wherein a surface of the position fixing holding plate is subjected to an antireflection process.

(Claim 8)
The liquid crystal display device according to claim 1, wherein the liquid crystal cell is in a VA mode.

(Claim 9)
The liquid crystal display device according to claim 1, wherein the retardation film further has an optically anisotropic layer.

(Claim 10)
The liquid crystal display device according to claim 1, wherein the backlight is a direct type light emitting diode.

  According to the present invention, it is possible to provide a liquid crystal display device in which peripheral light leakage is remarkably reduced even in a large screen TV.

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

  The liquid crystal display device of the present invention is a liquid crystal display device having at least one polarizing plate having a surface polarizing plate protective film, a polarizer, and a retardation film, and a liquid crystal cell, wherein the retardation film side of the polarizing plate is the liquid crystal cell side. The position fixing holding plate is attached directly or via another layer to the surface protective film of the polarizing plate, and the retardation film side is not attached to the liquid crystal cell.

  When the surface of the retardation film side of the polarizing plate is fixed to the liquid crystal cell with an adhesive as in the past, if a dimensional change occurs in the polarizing plate fixed to the liquid crystal cell, a stress is generated between the adhesive layer and the polarizing plate. As a result, an unnecessary phase difference is generated in the polarizing plate, which may cause a so-called frame-like light leakage failure, in which light leaks from the periphery of the screen and appears white when the liquid crystal display device displays black. is there. The reason why the light leakage becomes a frame shape is that the stress is more likely to occur at the edge portion than at the center portion of the polarizing plate. In particular, when a large polarizing plate exceeding 30 cm × 40 cm is used, the conventional design by optimizing the polarizing plate and the film member has not been sufficient.

  As a result of intensive studies in view of the above problems, the present inventor has been arranged so that the retardation film side of the polarizing plate is the liquid crystal cell side, and the position fixing holding plate is directly or via other layers on the surface protective film of the polarizing plate. As a result of finding out that the retardation film side is not attached to the liquid crystal cell, it is possible to control the development of unnecessary retardation due to environmental fluctuations of the retardation film.

  Hereinafter, the present invention will be described in detail for each element.

(Polarizer)
The polarizing plate according to the present invention is obtained by laminating a protective film on the surface of a polarizing film obtained by adsorbing and orienting a dichroic dye on a uniaxially stretched polyvinyl alcohol-based resin film, and a retardation film on the opposite surface. . The polyvinyl alcohol-based resin constituting the polarizing film is usually obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The degree of saponification of the polyvinyl alcohol resin is usually 85 to 100 mol%, preferably 98 to 100 mol%. This polyvinyl alcohol-based resin may be further modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 to 10,000, preferably 1500 to 10,000.

  A polarizing plate usually has a process of uniaxially stretching such a polyvinyl alcohol resin film, a process of dyeing a polyvinyl alcohol resin film with a dichroic dye to adsorb iodine or a dichroic dye, and a dichroic dye adsorbing. A step of treating the obtained polyvinyl alcohol resin film with an aqueous boric acid solution, a step of washing with water after the treatment with the boric acid aqueous solution, and a uniaxially stretched polyvinyl alcohol resin film on which the dichroic dye is adsorbed and oriented by these steps It is manufactured through a process of pasting a protective film. Uniaxial stretching may be performed before dyeing with a dichroic dye, may be performed simultaneously with dyeing with a dichroic dye, or may be performed after dyeing with a dichroic dye. When uniaxial stretching is performed after dyeing with a dichroic dye, this uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Of course, it is also possible to perform uniaxial stretching in these plural stages. For uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched or uniaxially stretched using a hot roll. Moreover, the dry-type extending | stretching which extends | stretches in air | atmosphere may be sufficient, and the wet extending | stretching which extends | stretches in the state swollen with the solvent may be sufficient. The draw ratio is usually about 4 to 8 times.

  In order to dye the polyvinyl alcohol resin film with the dichroic dye, for example, the polyvinyl alcohol resin film may be immersed in an aqueous solution containing the dichroic dye. The dichroic dye referred to here is specifically iodine or a dichroic dye.

  When iodine is used as the dichroic dye, a method of dyeing a polyvinyl alcohol resin film by dipping in an aqueous solution containing iodine and potassium iodide is usually employed. The content of iodine in this aqueous solution is usually about 0.01 to 0.5 parts by mass per 100 parts by mass of water, and the content of potassium iodide is usually about 0.5 to 10 parts by mass per 100 parts by mass of water. It is. The temperature of this aqueous solution is usually about 20 to 40 ° C., and the immersion time in this aqueous solution is usually about 30 to 300 seconds.

On the other hand, when a dichroic dye is used as the dichroic dye, a method of immersing and dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye is usually employed. The content of the dichroic dye in this aqueous solution is usually about 1 × 10 ⁻³ to 1 × 10 ⁻² parts by mass per 100 parts by mass of water. This aqueous solution may contain an inorganic salt such as sodium sulfate. The temperature of this aqueous solution is usually about 20 to 80 ° C., and the immersion time in this aqueous solution is usually about 30 to 300 seconds.

  The boric acid treatment after dyeing with a dichroic dye is performed by immersing the dyed polyvinyl alcohol resin film in an aqueous boric acid solution. The boric acid content in the boric acid aqueous solution is usually about 2 to 15 parts by mass, preferably about 5 to 12 parts by mass per 100 parts by mass of water. When iodine is used as the dichroic dye, the aqueous boric acid solution preferably contains potassium iodide. The content of potassium iodide in the boric acid aqueous solution is usually about 2 to 20 parts by mass, preferably 5 to 15 parts by mass per 100 parts by mass of water. The immersion time in the boric acid aqueous solution is usually about 100 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. Moreover, the temperature of boric acid aqueous solution is 50 degreeC or more normally, Preferably it is 50-85 degreeC.

  The polyvinyl alcohol resin film after the boric acid treatment is usually washed with water. The water washing treatment is performed, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. After washing with water, a drying process is performed to obtain a polarizing film. The temperature of water in the water washing treatment is usually about 5 to 40 ° C., and the immersion time is usually about 2 to 120 seconds. The drying process performed thereafter is usually performed using a hot air dryer or a far infrared heater. The drying temperature is usually 40 to 100 ° C. The processing time in the drying process is usually about 120 seconds to 600 seconds.

  Although there is no restriction | limiting in particular in the width | variety of a polarizing film, The width same as the width | variety of an above described polarizing plate protective film or retardation film is preferable, Specifically, the film width of 1.4 m or more is preferable, and especially 1.4m-4m. preferable.

  The polarizing film thus obtained is made into a polarizing plate by laminating a polarizing plate protective film on the surface and a retardation film on the opposite surface in the same manner as a normal polarizing film.

  At that time, the film to be laminated may be a strip-like sheet or a roll. Furthermore, each combination may be sufficient. Since it can be laminated | stacked by roll-to-roll if it is a roll-shaped thing, since it is excellent in productivity, it is preferable.

  In preparation of the polarizing plate which concerns on this invention, when using a cyclic olefin resin film as a phase difference film, it is preferable to provide an adhesive layer on the cyclic olefin resin film side, and to bond with a polarizer.

  When a cellulose ester film is used as the surface protective film or retardation film, it is desirable to saponify the surface with an alkaline aqueous solution prior to bonding with a polarizer.

  The surface polarizing plate protective film produced as described above, a polarizer, a polarizing plate bonded with a retardation film, a position fixing holding plate is attached directly or via another layer to the surface protective film side, The liquid crystal display device of the present invention is formed without attaching the retardation film side to the liquid crystal cell. The position fixing and holding plate is preferably a front plate or a light diffusing plate.

  The front plate here refers to a detachable translucent plate that is installed on the outermost surface of the liquid crystal display device and can position and hold the polarizing plate. It is also possible to perform clear hard coat processing, anti-glare processing, or antireflection processing even if the surface is left as it is.

  The light diffusing plate is a translucent plate that is installed on the backlight side of the liquid crystal display device and performs light diffusing so as to obtain a preferable light amount distribution, or a single-sided matte treatment (rough surface).

(Liquid crystal display device)
By incorporating the polarizing plate according to the present invention into a liquid crystal display device, various liquid crystal display devices with excellent visibility can be manufactured. The polarizing plate of the present invention is preferably a reflective, transmissive, transflective LCD or TN, STN, OCB, HAN, VA (PVA, MVA), or IPS LCD. VA type is particularly preferred. Further, in a large-screen liquid crystal display device having a 30-inch or larger screen, light leakage is remarkably reduced, color unevenness and wavy unevenness are reduced, and eyes are not tired even during long-time viewing.

  The liquid crystal display device according to the present invention will be described with reference to the drawings, but is not limited thereto.

  FIG. 1 is a schematic view showing a preferred example of a liquid crystal display device according to the present invention.

  If it demonstrates from the observation surface side of a liquid crystal display device, the polarizing plate protective film 2 will be laminated | stacked on the surface side of the polarizer 1, and the front plate 4 which is a position fixing holding plate will be further adhere | attached through the adhesion layer 3. FIG. A retardation film 5 is laminated on the back side of the polarizer 1 to form a polarizing plate A, and a liquid crystal cell 6 is further disposed. Although the retardation film 5 and the liquid crystal cell 6 may be in contact with each other, it is preferable that a fluid medium layer 7 is provided between the retardation film and the liquid crystal cell. The fluid medium layer means a fluid layer such as a gas layer such as air or nitrogen, a liquid layer such as water or alcohol, gelatin, a gelatin derivative, a protein other than gelatin, a sugar derivative, a cellulose derivative, or a hydrophilic colloid. A gas layer and a fluid solid layer are preferable, and a gas layer which is most preferably air is preferable.

  The position fixing holding plate is preferably formed of at least one selected from a cyclic olefin resin, an acrylic resin, a polyester, and a glass plate. An acrylic resin or a glass plate is more preferable. For example, as an acrylic resin, Acrypet MD, VH, MF, V (manufactured by Mitsubishi Rayon Co., Ltd.), Hyperl M-4003, M-4005, M-4006, M-4202, M-5000, M-5001, M-4501 (manufactured by Negami Kogyo Co., Ltd.), Dialnal BR-50, BR-52, BR-53, BR-60, BR-64, BR-73, BR-75, BR-77, BR-79, BR -80, BR-82, BR-83, BR-85, BR-87, BR-88, BR-90, BR-93, BR-95, BR-100, BR-101, BR-102, BR-105 BR-106, BR-107, BR-108, BR-112, BR-113, BR-115, BR-116, BR-117, BR-118, etc. (Mitsubishi Rayon Co., Ltd.) acrylic and The methacrylic monomers such as various homopolymers and copolymers were prepared as raw materials are commercially available, can be appropriately selected and processed preferable from this.

  Furthermore, it is preferable that the antireflection layer mentioned later is processed into the surface, or the film with an antireflection layer is bonded.

  Although there is no restriction | limiting in particular in the thickness of a position fixed holding | maintenance board, it is preferable that it is 0.5 mm or more from the relationship of holding | maintenance of a polarizing plate, and it is more preferable that it is 1 mm or more. In the case of the front plate, the transmittance is preferably the same as the film used for the polarizing plate. Specifically, the transmittance is desirably 90% or more, more preferably 92% or more. More preferably, it is 93% or more.

  The polarizing plate according to the present invention is sufficient if at least one polarizing plate has the configuration of the present invention. For example, when the polarizing plate on the observation surface side has the configuration of the present invention, the polarizing plate on the backlight side of the liquid crystal display device As usual, a polarizing plate protective film or a retardation film may be adhered to the liquid crystal cell. Preferably, the polarizing plate film is not bonded to the liquid crystal cell as in the observation side.

  In a preferred mode on the backlight side of the liquid crystal display device, the retardation film 5 is in contact with the liquid crystal cell 6 as shown in FIG. 1, or the polarizing plate B is disposed via the fluid medium layer 7. A polarizing plate protective film 2 is laminated on the opposite side of the polarizing plate, and is further adhered to a resin or glass plate via an adhesive layer 3. The resin or glass plate may be the same as the front plate or the light diffusion plate 8.

  The backlight of the liquid crystal display device is preferably a direct backlight type. Specific examples of the direct backlight system include the following.

(1) Japanese Patent Application Laid-Open No. 2001-215497 On a display screen due to variation in the position of fluorescent tubes in a backlight device of a large-sized liquid crystal display panel by forming a fluorescent tube arrangement positioning portion and / or a fluorescent tube support portion and a reflecting plate by integral molding. Brightness unevenness is improved, and the backlight structure is simplified.

(2) Japanese Patent Application Laid-Open No. 2001-305535 In a direct type backlight that is placed under a transmissive liquid crystal display device and irradiates light to the transmissive liquid crystal display device, the direct type backlight includes at least a circuit board, a light emitting element, and a pyramid shape. And a light emitting surface (diffusion sheet). The pyramidal hole has a shape extending from the light emitting element toward the light emitting surface, and has a structure that expands in a stepped manner, and faces the diffusion sheet. In the light emitting surface of a direct type backlight using a point light source such as an LED, and having a reflective surface having a curvature that reflects the primary reflected light from the central part of the diffusion sheet to the peripheral edge of the diffusion sheet Reduce brightness unevenness.

(3) Japanese Patent Application Laid-Open No. 2003-215585 A direct-type backlight body includes a plurality of fluorescent tubes arranged side by side, a housing that houses these fluorescent tubes, and a light diffusing plate that is disposed so as to cover the opening of the housing And consists of Then, a plurality of ribs are integrally formed on the lower surface of the light diffusion plate made of translucent resin. The ribs provided on the lower surface of the light diffusion plate are linear protrusions parallel to the longitudinal direction of the light diffusion plate. Thereby, the intensity | strength of the longitudinal direction of a light diffusing plate can go up, and the curvature of a light diffusing plate can be prevented.

(4) JP 2004-29091 A total of 100 parts by mass of 99.7 to 80% by mass of polycarbonate resin and 0.3 to 20% by mass of transparent fine particles having an average particle diameter of 1 to 30 μm and 0.005 to 0 of a fluorescent brightening agent With a light diffusion plate for direct backlight of polycarbonate resin having a thickness of 0.5 to 3.0 mm formed from a resin composition consisting of 1 part by mass, it has excellent surface light emission and less uneven brightness, In addition, it is possible to provide a light diffusion plate made of polycarbonate resin having an excellent color tone, particularly a light diffusion plate made of polycarbonate resin suitable for a direct type backlight system of a large liquid crystal display or a large liquid crystal television.

(5) Japanese Patent Application Laid-Open No. 2004-102119 A reflector for direct type backlight arranged behind a plurality of straight tube type light sources for illuminating a liquid crystal display panel and reflecting light from the light sources to the liquid crystal display panel side Then, by forming a polycarbonate resin sheet having a thickness of 0.6 to 1.5 mm by matched die molding, a plurality of peak portions are formed in parallel at an equal pitch, and the bottom portion 12 is formed between the peak portions. It is formed and the light source is arranged at a position directly above the center of the bottom, and it is easy to increase the size, and even if the size is increased, there is almost no local luminance unevenness due to deformation and excellent reflection performance. A reflector for a direct backlight of a liquid crystal display device can be provided.

  In particular, the liquid crystal display device using the polarizing plate of the present invention has a size of 15 inches or more, and the present invention is effective for a thin liquid crystal display device having a large influence of heat in which the distance between the light source and the polarizing plate is shortened. A planar white LED light source is a light source preferably used in the liquid crystal display device of the present invention.

(Adhesive, adhesive layer)
As the pressure-sensitive adhesive used in the present invention, a pressure-sensitive adhesive having a storage elastic modulus at 25 ° C. of 1.0 × 10 ⁴ Pa to 1.0 × 10 ⁹ Pa in at least a part of the pressure-sensitive adhesive layer is used. preferable. More preferably, it is 1.0 × 10 ^{5 to} 1.0 × 10 ⁹ Pa, and when the elastic modulus of the pressure-sensitive adhesive is less than 1.0 × 10 ⁴ Pa, sufficient adhesive strength cannot be obtained, and the shaft misalignment is caused. If the elastic modulus exceeds 1.0 × 10 ⁹ Pa when the heat resistance test is performed, the pressure-sensitive adhesive is too hard, which causes a problem that cracks or chips are generated during the punching process. The type is not particularly limited, but a curable pressure-sensitive adhesive that forms a high molecular weight body or a crosslinked structure by various chemical reactions after applying and bonding the pressure-sensitive adhesive is suitably used. Specific examples include, for example, urethane adhesives, epoxy adhesives, aqueous polymer-isocyanate adhesives, curable adhesives such as thermosetting acrylic adhesives, moisture-curing urethane adhesives, polyether methacrylate types, Examples include anaerobic pressure-sensitive adhesives such as ester-based methacrylate type and oxidized polyether methacrylate, cyanoacrylate-based instantaneous pressure-sensitive adhesives, and acrylate-peroxide-based two-component instantaneous pressure-sensitive adhesives.

  The pressure-sensitive adhesive may be a one-component type or a type that is used by mixing two or more components before use. The pressure-sensitive adhesive may be a solvent system using an organic solvent as a medium, or an aqueous system such as an emulsion type, a colloidal dispersion type, or an aqueous solution type that is a medium containing water as a main component. It may be a solvent type. The concentration of the pressure-sensitive adhesive liquid may be appropriately determined depending on the film thickness after adhesion, a coating machine, coating conditions, and the like, and is usually 0.1 to 50% by mass.

  The storage elastic modulus at 25 ° C. of the pressure-sensitive adhesive is a value obtained by dynamic viscoelasticity measurement, specifically, a value measured by the method described in the storage elastic modulus measurement method described later. The thickness of the adhesive layer after curing is preferably 0.005 to 50 μm, more preferably 0.01 to 10 μm. If the thickness is less than 0.005 μm, sufficient adhesive strength cannot be obtained, and if it exceeds 50 μm, fading of the polarizing plate may occur during the moisture resistance test.

  Further, a post-curing pressure-sensitive adhesive may be used as the pressure-sensitive adhesive to be used. For example, the pressure-sensitive adhesive layer at the center of the polarizing plate can be made harder than the periphery by post-curing. The means for post-curing is not particularly limited, but it is preferable to use heat, light or the like.

  The method for forming the pressure-sensitive adhesive layer is not particularly limited and includes general methods such as a method of applying a pressure-sensitive adhesive solution by a method such as a gravure coater, a micro gravure coater, a comma coater, a bar coater, a spray coating, an ink jet method, or the like. It is done.

<Measurement method of storage modulus of adhesive layer>
An adhesive layer molding composition was formed on a polyethylene terephthalate film support. The adhesive layer was peeled off, and the adhesive layer was stored at 25 ° C. in a temperature rising mode (temperature rising rate 5 ° C./min, frequency 10 Hz) by a dynamic viscoelasticity measuring device (“ARES” manufactured by Rheometric Co.). Measure the elastic modulus.

(Base material)
The polarizing plate protective film and retardation film of the present invention are preferably the following transparent plastic substrates.

  As the transparent plastic substrate used in the present invention, it is mentioned that the production is easy, the adhesiveness with the hard coat layer is good, the optical transparency is preferable, etc. Is preferably used.

  The term “transparent” as used in the present invention means that the visible light transmittance is 60% or more, preferably 80% or more, and particularly preferably 90% or more. More preferably, it is 92% or more, and particularly preferably 93% or more.

  Although it will not specifically limit if it has said property, For example, a cellulose-ester type film, a polyester-type film, a polycarbonate-type film, a polyarylate-type film, a polysulfone (a polyether sulfone is also included) type film, a polyethylene terephthalate, polyethylene Polyester film such as naphthalate, polyethylene film, polypropylene film, cellophane, cellulose diacetate film, cellulose triacetate, cellulose acetate butyrate film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene film, Polycarbonate film, cyclic olefin resin film (Arton (manufactured by JSR), Zeo) , ZEONOR (manufactured by Nippon Zeon Co., Ltd.), polymethylpentene film, polyetherketone film, polyetherketoneimide film, polyimide film, polyamide film, fluororesin film, nylon film, polymethylmethacrylate film, acrylic film or A glass plate etc. can be mentioned. Among them, as the polarizing plate protective film and the retardation film, a cellulose ester film, a polycarbonate film, a polysulfone (including polyether sulfone) and a cyclic olefin resin film are preferable. In the present invention, the polarizing plate protective film is particularly a cellulose ester. Films (for example, Konica Minolta-tak product names KC8UX2MW, KC8UX-H, KC4UX2MW, KC5UX, KC8UY, KC8UY-HA, KC4UY, KC5UN, KC12UR (manufactured by Konica Minolta Opto Co., Ltd., production cost), , Preferably from the viewpoint of isotropicity, adhesiveness and the like. The retardation film is preferably a cyclic olefin resin film or a cellulose ester film. These films may be films produced by melt casting film formation or films produced by solution casting film formation.

  As the optical properties of the base film, those having a retardation value Rt in the film thickness direction represented by the following formulas (i) and (ii) of −100 nm to 400 nm and an in-plane retardation value Ro of 0 nm to 1000 nm are shown. Preferably used.

  In the retardation film, Ro and Rt preferably satisfy the following ranges.

20 (nm) ≦ Ro ≦ 300 (nm)
−100 (nm) ≦ Rt ≦ 400 (nm)
Formula (i) Ro = (nx−ny) × d
Formula (ii) Rt = {(nx + ny) / 2−nz} × d
In the formula, nx is the refractive index in the slow axis direction in the support surface, ny is the refractive index in the fast axis direction in the support surface, nz is the refractive index in the thickness direction of the support, and d is Represents the thickness of the support.

(Cellulose ester film)
First, the cellulose ester film preferably used in the present invention will be described.

  The cellulose ester preferably used in the present invention is a cellulose ester of an aliphatic carboxylic acid or aromatic carboxylic acid having 2 to 22 carbon atoms, particularly cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate phthalate. Is preferably used.

  In particular, when the substitution degree of the acetyl group is X and the substitution degree of the acyl group having 3 to 22 carbon atoms is Y, a base film having a mixed acid ester of cellulose in which X and Y are in the following ranges is preferably used.

2.3 ≦ X + Y ≦ 3.0
0.1 ≦ Y ≦ 1.2
In particular, 2.5 ≦ X + Y ≦ 2.85
It is preferable that 0.3 ≦ Y ≦ 1.2.

  When cellulose ester is used as the base film according to the present invention, the cellulose used as a raw material for the cellulose ester is not particularly limited, and examples thereof include cotton linter, wood pulp (derived from coniferous tree, derived from broadleaf tree), kenaf and the like. . Moreover, the cellulose ester obtained from them can be mixed and used in arbitrary ratios, respectively. When the acylating agent is an acid anhydride (acetic anhydride, propionic anhydride, butyric anhydride), these cellulose esters use an organic solvent such as acetic acid or an organic solvent such as methylene chloride, and It can be obtained by reacting with a cellulose raw material using a protic catalyst.

When the acylating agent is acid chloride (CH ₃ COCl, C ₂ H ₅ COCl, C ₃ H ₇ COCl), the reaction is carried out using a basic compound such as an amine as a catalyst. Specifically, it can be synthesized with reference to the method described in JP-A-10-45804. In addition, the cellulose ester used in the present invention is obtained by mixing and reacting the amount of the acylating agent in accordance with the degree of substitution. In the cellulose ester, these acylating agents react with hydroxyl groups of cellulose molecules. Cellulose molecules are composed of many glucose units linked together, and the glucose unit has three hydroxyl groups. The number of acyl groups derived from these three hydroxyl groups is called the degree of substitution (mol%). For example, cellulose triacetate has acetyl groups bonded to all three hydroxyl groups of the glucose unit (actually 2.6 to 3.0).

  The cellulose ester used in the present invention is a mixed fatty acid ester of cellulose in which a propionate group or a butyrate group is bonded in addition to an acetyl group such as cellulose acetate propionate, cellulose acetate butyrate, or cellulose acetate propionate butyrate. Is particularly preferably used. The butyryl group forming butyrate may be linear or branched.

  Cellulose acetate propionate containing a propionate group as a substituent has excellent water resistance and is useful as a film for liquid crystal image display devices.

  The measuring method of the substitution degree of an acyl group can be measured according to the provisions of ASTM-D817-96.

  The number average molecular weight of the cellulose ester is preferably 70000 to 250,000, since it has high mechanical strength when molded and an appropriate dope viscosity, and more preferably 80000 to 200000.

  These cellulose esters are pressurized by applying a cellulose ester solution (dope) generally called a solution casting film forming method onto, for example, an endless metal belt for infinite transport or a support for casting of a rotating metal drum. It is preferable to manufacture the dope from a die by casting (casting).

  The organic solvent used for preparing these dopes is preferably capable of dissolving cellulose ester and having an appropriate boiling point, for example, methylene chloride, methyl acetate, ethyl acetate, amyl acetate, methyl acetoacetate, acetone, tetrahydrofuran 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-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, 1,3-dimethyl-2-imidazolidinone, etc. It is possible, organic halogen compounds such as methylene chloride, dioxolane derivatives, methyl acetate, ethyl acetate, acetone, methyl acetoacetate, and the like are preferable organic solvents (i.e., good solvent), and as.

  Moreover, as shown in the following film forming process, it is used from the viewpoint of preventing foaming in the web when the solvent is dried from the web (dope film) formed on the casting support in the solvent evaporation process. The boiling point of the organic solvent is preferably 30 to 80 ° C. For example, the good solvent described above has a boiling point of methylene chloride (boiling point 40.4 ° C), methyl acetate (boiling point 56.32 ° C), acetone (boiling point 56.56 ° C). 3 ° C.), ethyl acetate (boiling point 76.82 ° C.) and the like.

  Among the good solvents described above, methylene chloride or methyl acetate, which is excellent in solubility, is preferably used.

  It is preferable to contain 0.1 mass%-40 mass% of C1-C4 alcohol other than the said organic solvent. It is particularly preferable that the alcohol is contained at 5 to 30% by mass. After casting the dope described above onto a casting support, the solvent starts to evaporate and the alcohol ratio increases and the web (dope film) gels, making the web strong and peeling from the casting support. It is also used as a gelling solvent for facilitating the dissolution, and when these ratios are small, it also has a role of promoting dissolution of the cellulose ester of the non-chlorine organic solvent.

  Examples of the alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol and the like.

  Of these solvents, ethanol is preferred because it has good dope stability, relatively low boiling point, good drying properties, and no toxicity. It is preferable to use a solvent containing 5% by mass to 30% by mass of ethanol with respect to 70% by mass to 95% by mass of methylene chloride. Methyl acetate can be used in place of methylene chloride. At this time, the dope may be prepared by a cooling dissolution method.

  The cellulose ester film used in the present invention is preferably at least stretched in the width direction, and is 1.01 times to the width direction when the residual solvent amount is 3% by mass to 40% by mass in the solution casting process. The film is preferably stretched 1.5 times. When used as a retardation film, it is more preferably biaxial stretching in the width direction and the longitudinal direction, and when the residual solvent amount is 3% by mass to 40% by mass, respectively in the width direction and the longitudinal direction. It is desirable to be stretched by 1.01 times to 1.5 times. By doing in this way, the retardation film excellent in planarity and retardation performance can be obtained.

  When used as a retardation film, preferable retardation values in the present invention are Rt of -100 to 400 nm, Ro of 20 to 300 nm, and more preferably Ro of 30 to 70 nm.

  The residual solvent amount is represented by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Here, M is the mass of the web (cellulose ester film containing the solvent) at an arbitrary point in time, and N is the mass when the web of M is dried at 110 ° C. for 3 hours.

  Furthermore, by performing biaxial stretching and knurling, it is possible to remarkably improve the deterioration of the winding shape during storage of the long optical film in the form of a roll.

  In the present invention, the biaxially stretched cellulose ester film is preferably a transparent support having a light transmittance of 90% or more, more preferably 93% or more.

The cellulose ester film according to the present invention preferably has a thickness of 10 μm to 100 μm, more preferably 40 μm to 80 μm, and moisture permeability was measured according to JIS Z 0208 (25 ° C., 90% RH). The value is preferably 200 g / m ² · 24 hours or less, more preferably 10 to 180 g / m ² · 24 hours or less, and particularly preferably 160 g / m ² · 24 hours or less. In particular, it is preferable that the film thickness is 10 μm to 80 μm and the moisture permeability is within the above range.

  In the present invention, it is preferable to use a long film, and specifically, a film having a length of about 100 m to 5000 m is shown, which is usually provided in a roll shape. Further, the width of the base film is preferably 1.4 m or more from the viewpoint of productivity. More preferably, it is the range of 1.4-4m.

  When a cellulose ester film is used for the polarizing plate protective film or the retardation film of the present invention, it is preferable to contain 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 or 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 For trimellitic acid plasticizers such as ethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, diphenyl phthalate, dicyclohexyl phthalate, 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, methylphthalylethyl glycolate, butylphthalylbutyl glycolate, 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 trimethylolpropane tribenzoate, butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters.

  As the polyester plasticizer, a copolymer of a dibasic acid such as an aliphatic dibasic acid, an alicyclic dibasic acid, or an aromatic dibasic acid and a glycol 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 the 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 amount of these plasticizers used is preferably 1% by mass to 20% by mass and particularly preferably 3% by mass to 13% by mass with respect to the cellulose ester in terms of film performance, processability and the like.

  For the cellulose ester film of the present invention, an ultraviolet absorber is preferably used.

  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 of the ultraviolet absorber preferably used in the present invention include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. However, it is not limited to these.

  Specific examples of the benzotriazole-based ultraviolet absorbers include the following ultraviolet absorbers, but the present invention is not limited thereto.

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)
UV-9: Octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H-benzotriazol-2-yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl- 4-Hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate (TINUVIN109, manufactured by Ciba)
Moreover, although the following specific example is 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 ultraviolet absorber preferably used in the present invention, a benzotriazole-based ultraviolet absorber and a benzophenone-based ultraviolet absorber that are highly transparent and excellent in preventing the deterioration of the polarizing plate and the liquid crystal are preferable, and unnecessary coloring is less. A benzotriazole-based ultraviolet absorber is particularly preferably used.

  Moreover, the ultraviolet absorber whose distribution coefficient described in Unexamined-Japanese-Patent No. 2001-187825 is 9.2 or more improves the surface quality of a long film, and is excellent also in applicability | paintability. In particular, it is preferable to use an ultraviolet absorber having a distribution coefficient of 10.1 or more.

  Further, the polymer ultraviolet absorbers described in the general formula (1) or general formula (2) described in JP-A-6-148430 and the general formulas (3), (6), and (7) of Japanese Patent Application No. 2000-156039 ( Alternatively, an ultraviolet 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.

In addition, it is preferable to add inorganic or organic fine particles to the cellulose ester film used in the present invention in order to impart slipperiness and to improve scratch resistance and the like. Examples of inorganic fine particles include silicon oxide, titanium oxide, aluminum oxide, tin oxide, zinc oxide, calcium carbonate, barium sulfate, talc, kaolin, calcium sulfate, and the like, and examples of organic fine 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, polyolefin resin powder, polyester resin powder And polyamide resin powder, polyimide resin powder, and polyfluorinated ethylene resin powder. Of these, silicon oxide fine particles (SiO ₂ fine particles) are preferable.

  The primary average particle diameter of the fine particles added to the cellulose ester film used in the present invention is preferably 20 nm or less, more preferably 5 to 16 nm, and particularly preferably 5 to 12 nm. These fine particles preferably form secondary particles having a particle diameter of 0.1 to 5 μm and are contained in the cellulose ester film, and the preferable average particle diameter is 0.1 to 2 μm, more preferably 0.2 to 0.6 μm. Thereby, the unevenness | corrugation about 0.1-1.0 micrometer high can be formed in the film surface, and, thereby, appropriate slipperiness can be given to the film surface.

  The primary average particle diameter of the fine particles used in the present invention is measured by observing particles with a transmission electron microscope (magnification 500,000 to 2,000,000 times), observing 100 particles, and using the average value, the primary value is measured. The average particle size was taken.

  The apparent specific gravity of the fine particles is preferably 70 g / liter or more, more preferably 90 to 200 g / liter, and particularly preferably 100 to 200 g / liter. A larger apparent specific gravity makes it possible to make a high-concentration dispersion, which improves haze and agglomerates, and is preferable when preparing a dope having a high solid content concentration as in the present invention. Are particularly preferably used.

SiO ₂ fine particles having an average primary particle diameter of 20 nm or less and an apparent specific gravity of 70 g / liter or more are, for example, a mixture of vaporized silicon tetrachloride and hydrogen burned in air at 1000 to 1200 ° C. Can be obtained. For example, it is marketed by the brand name of Aerosil 200V and Aerosil R972V (above, Nippon Aerosil Co., Ltd. product), and can use them.

The apparent specific gravity described above is calculated by the following formula by measuring a weight of SiO ₂ fine particles in a graduated cylinder and measuring the weight at that time.

Apparent specific gravity (g / liter) = SiO ₂ mass (g) / SiO ₂ volume (liter)
Examples of the method for preparing the fine particle dispersion used in the present invention include the following three types.

<< Preparation Method A >>
After stirring and mixing the solvent and fine particles, dispersion is performed with a disperser. This is a fine particle dispersion. The fine particle dispersion is added to the dope solution and stirred.

<< Preparation Method B >>
After stirring and mixing the solvent and fine particles, dispersion is performed with a disperser. This is a fine particle dispersion. Separately, a small amount of cellulose triacetate is added to the solvent and dissolved by stirring. The fine particle dispersion is added to this and stirred. This is a fine particle addition solution. The fine particle additive solution is sufficiently mixed with the dope solution using an in-line mixer.

<< Preparation Method C >>
Add a small amount of cellulose triacetate to the solvent and dissolve with stirring. Fine particles are added to this and dispersed by a disperser. This is a fine particle addition solution. The fine particle additive solution is sufficiently mixed with the dope solution using an in-line mixer.

Preparation method A is excellent in the dispersibility of SiO ₂ fine particles, and preparation method C is excellent in that the SiO ₂ fine particles are difficult to re-aggregate. Among them, the preparation method B described above is a dispersion of SiO ₂ particles, a preferred preparation method SiO ₂ particles have excellent reagglomeration hardly like, both.

《Distribution method》
The concentration of SiO ₂ when the SiO ₂ fine particles are mixed with a solvent and dispersed is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, and most preferably 15 to 20% by mass. A higher dispersion concentration is preferable because liquid turbidity with respect to the added amount tends to be low, and haze and aggregates are improved.

  The solvent used is preferably lower alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and the like. Although it does not specifically limit as solvents other than a lower alcohol, It is preferable to use the solvent used at the time of film forming of a cellulose ester.

The addition amount of SiO ₂ fine particles to the cellulose ester relative to 100 parts by weight of cellulose ester, SiO ₂ fine particles is preferably 5.0 parts by 0.01 parts by weight, 0.05 parts by weight to 1.0 parts by weight is more Preferably, 0.1 mass part-0.5 mass part is the most preferable. The larger the added amount, the better the dynamic friction coefficient, and the smaller the added amount, the less aggregates.

As the disperser, a normal disperser can be used. Dispersers can be broadly divided into media dispersers and medialess dispersers. For dispersion of SiO ₂ fine particles, a medialess disperser is preferred because of low haze. Examples of the media disperser include a ball mill, a sand mill, and a dyno mill. Examples of the medialess disperser include an ultrasonic type, a centrifugal type, and a high pressure type. In the present invention, a high pressure disperser is preferable. The high pressure dispersion device is a device that creates special conditions such as high shear and high pressure by passing a composition in which fine particles and a solvent are mixed at high speed through a narrow tube. When processing with a high-pressure dispersion apparatus, for example, the maximum pressure condition inside the apparatus is preferably 9.807 MPa or more in a thin tube having a tube diameter of 1 to 2000 μm. More preferably, it is 19.613 MPa or more. Further, at that time, those having a maximum reaching speed of 100 m / second or more and those having a heat transfer speed of 420 kJ / hour or more are preferable.

  Examples of the high-pressure dispersing apparatus include an ultra-high pressure homogenizer (trade name: Microfluidizer) manufactured by Microfluidics Corporation or a nanomizer manufactured by Nanomizer, and other manton gorin type high-pressure dispersing apparatuses such as homogenizer manufactured by Izumi Food Machinery. And UHN-01 manufactured by Sanwa Machinery Co., Ltd.

  In addition, casting a dope containing fine particles so as to be in direct contact with the casting support is preferable because a film having high slip properties and low haze can be obtained.

  It is also preferable that a reactive metal compound or a hydrolyzate thereof is added to the dope composition of the cellulose ester film so that metal oxide fine particles are contained in the film. Preferred examples of the reactive metal compound include metal alkoxides such as Si, Al, Ti, and Zr.

  The cellulose ester film used in the present invention may have a multilayer structure by a co-casting method using a plurality of dopes.

  Co-casting is a sequential multilayer casting method in which two or three layers are configured through different dies, and a simultaneous multilayer casting method in which two or three slits are combined in a die having two or three slits. Any of the multilayer casting methods combining sequential multilayer casting and simultaneous multilayer casting may be used.

  In addition, the cellulose ester used in the present invention is preferably used as a support having a small amount of bright spot foreign matter when formed into a film. In the present invention, the bright spot foreign material is a structure in which two polarizing plates are arranged orthogonally (crossed Nicols), a cellulose ester film is arranged between them, and light from a light source is applied from one side to the other side. When the cellulose ester film is observed, the light from the light source appears to leak.

  At this time, the polarizing plate used for the evaluation is desirably composed of a protective film having no bright spot foreign matter, and a polarizing plate using a glass plate for protecting the polarizer is preferably used. The occurrence of bright spot foreign matter is considered to be one of the causes of unacetylated or low acetylated cellulose contained in the cellulose ester, as a countermeasure, using a cellulose ester with a small amount of unacetylated cellulose, Further, it can be removed and reduced by filtering the dope solution in which the cellulose ester is dissolved. Further, the thinner the film thickness, the smaller the number of bright spot foreign matter per unit area, and the lower the content of cellulose ester contained in the film, the fewer bright spot foreign matter.

The bright spot foreign matter having a bright spot diameter of 0.01 mm or more is preferably 200 pieces / cm ² or less, more preferably 100 pieces / cm ² or less, 50 pieces / cm ² or less, 30 pieces / cm. ² or less, preferably 10 pieces / cm ² or less, but it is particularly preferred that a 0.

Moreover, it is preferable that it is 200 pieces / cm < ² > or less also about 0.005 mm-0.01 mm bright spot, More preferably, it is 100 pieces / cm < ² > or less, 50 pieces / cm < ² > or less, 30 pieces / cm < ² > or less. The number is preferably 10 / cm ² or less, but particularly preferred is the case where the bright spot is zero. A small number of bright spots of 0.005 mm or less is preferable.

  When removing bright spot foreign matter by filtration, it is preferable to filter the composition in which a plasticizer is added and mixed, rather than filtering a cellulose ester dissolved alone, because the bright spot foreign matter removal efficiency is high. As the filter medium, conventionally known materials such as glass fibers, cellulose fibers, filter paper, and fluororesins such as tetrafluoroethylene resin are preferably used, but ceramics, metals and the like are also preferably used. The absolute filtration accuracy is preferably 50 μm or less, more preferably 30 μm or less, and 10 μm or less, and particularly preferably 5 μm or less.

  These can also be used in combination as appropriate. The filter medium can be either a surface type or a depth type, but the depth type is preferably used because it is relatively less clogged.

(Cyclic olefin resin film)
Next, the cyclic olefin resin film used in the present invention will be described.

  The cyclic olefin resin used in the present invention comprises a polymer resin containing an alicyclic structure.

  A preferable cyclic olefin resin is a resin obtained by polymerizing or copolymerizing a cyclic olefin. Examples of the cyclic olefin include norbornene, dicyclopentadiene, tetracyclododecene, ethyltetracyclododecene, ethylidenetetracyclododecene, tetracyclo [7.4.0.110, 13.02,7] trideca-2,4. Unsaturated hydrocarbons of polycyclic structures such as 6,11-tetraene and derivatives thereof; cyclobutene, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, cyclo Examples thereof include monocyclic unsaturated hydrocarbons such as octene, 3a, 5,6,7a-tetrahydro-4,7-methano-1H-indene, cycloheptene, cyclopentadiene, cyclohexadiene, and derivatives thereof. These cyclic olefins may have a polar group as a substituent. Examples of the polar group include a hydroxyl group, a carboxyl group, an alkoxyl group, an epoxy group, a glycidyl group, an oxycarbonyl group, a carbonyl group, an amino group, an ester group, and a carboxylic acid anhydride group. Or a carboxylic anhydride group is preferred.

  Preferred cyclic olefin-based resins may be those obtained by addition copolymerization of monomers other than cyclic olefins. Addition copolymerizable monomers include ethylene, propylene, 1-butene, 1-pentene and other ethylene or α-olefins; 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl- Examples include dienes such as 1,4-hexadiene and 1,7-octadiene.

The cyclic olefin is obtained by an addition polymerization reaction or a metathesis ring-opening polymerization reaction. The polymerization is carried out in the presence of a catalyst. Examples of the addition polymerization catalyst include a polymerization catalyst composed of a vanadium compound and an organoaluminum compound. As a catalyst for ring-opening polymerization, a polymerization catalyst comprising a metal halide such as ruthenium, rhodium, palladium, osmium, iridium, platinum, nitrate or acetylacetone compound, and a reducing agent; or titanium, vanadium, zirconium, tungsten, molybdenum Examples thereof include a polymerization catalyst comprising a metal halide such as acetylacetone compound and an organoaluminum compound. The polymerization temperature, pressure and the like are not particularly limited, but the polymerization is usually carried out at a polymerization temperature of -50 ° C to 100 ° C and a polymerization pressure of 0 to 490 N / cm ² .

  The cyclic olefin-based resin used in the present invention is preferably a resin obtained by polymerizing or copolymerizing a cyclic olefin, followed by a hydrogenation reaction to change the unsaturated bond in the molecule to a saturated bond. The hydrogenation reaction is performed by blowing hydrogen in the presence of a known hydrogenation catalyst. Examples of hydrogenation catalysts include cobalt acetate / triethylaluminum, nickel acetylacetonate / triisobutylaluminum, transition metal compounds such as titanocene dichloride / n-butyllithium, zirconocene dichloride / sec-butyllithium, tetrabutoxytitanate / dimethylmagnesium / alkyl. Homogeneous catalyst consisting of a combination of metal compounds; heterogeneous metal catalyst such as nickel, palladium, platinum; nickel / silica, nickel / diatomaceous earth, nickel / alumina, palladium / carbon, palladium / silica, palladium / diatomaceous earth And a heterogeneous solid-supported catalyst in which a metal catalyst such as palladium / alumina is supported on a carrier.

  Or the following norbornene-type polymer is also mentioned as cyclic olefin resin. The norbornene-based polymer preferably has a norbornene skeleton as a repeating unit. Specific examples thereof include JP-A-62-252406, JP-A-62-2252407, and JP-A-2-133413. JP-A-63-145324, JP-A-63-264626, JP-A-1-240517, JP-B-57-8815, JP-A-5-39403, JP-A-5-43663 JP-A-5-43834, JP-A-5-70655, JP-A-5-279554, JP-A-6-206985, JP-A-7-62028, JP-A-8-176411, Although what was described in Kaihei 9-241484 etc. can utilize preferably, it is not limited to these. Moreover, these may be used individually by 1 type and may use 2 or more types together.

  In the present invention, among the norbornene-based polymers, those having a repeating unit represented by any of the following structural formulas (I) to (IV) are preferable.

  In the structural formulas (I) to (IV), A, B, C and D each independently represent a hydrogen atom or a monovalent organic group.

  Among the norbornene-based polymers, a polymer obtained by metathesis polymerization of at least one compound represented by the following structural formula (V) or (VI) and an unsaturated cyclic compound copolymerizable therewith. A hydrogenated polymer obtained by hydrogenating is also preferred.

  In the structural formula, A, B, C and D each independently represent a hydrogen atom or a monovalent organic group.

  Here, A, B, C and D are not particularly limited, but preferably an organic group may be linked via a hydrogen atom, a halogen atom, a monovalent organic group, or at least a divalent linking group. These may be the same or different. A or B and C or D may form a monocyclic or polycyclic structure. Here, the at least divalent linking group includes a hetero atom typified by an oxygen atom, a sulfur atom, and a nitrogen atom, and examples thereof include ether, ester, carbonyl, urethane, amide, thioether, and the like. It is not limited. In addition, the organic group may be further substituted via the linking group.

  Examples of other monomers copolymerizable with the norbornene-based monomer include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, C2-C20 alpha olefins, such as 1-hexadecene, 1-octadecene, 1-eicocene, and derivatives thereof; cyclobutene, cyclopentene, cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7 -Cycloolefins such as methano-1H-indene, and derivatives thereof; non 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 1,7-octadiene, etc. Conjugated dienes; and the like are used. Among these, an α-olefin, particularly ethylene is preferable.

  These other monomers copolymerizable with the norbornene-based monomer can be used alone or in combination of two or more. In the case of addition copolymerization of a norbornene monomer and another monomer copolymerizable therewith, the ratio of the structural unit derived from the norbornene monomer and the structural unit derived from the other monomer copolymerizable in the addition copolymer However, it is appropriately selected so that the mass ratio is usually 30:70 to 99: 1, preferably 50:50 to 97: 3, more preferably 70:30 to 95: 5.

  When the unsaturated bond remaining in the molecular chain of the synthesized polymer is saturated by a hydrogenation reaction, the hydrogenation rate is 90% or more, preferably 95% or more, particularly from the viewpoint of light resistance deterioration, weather resistance deterioration, etc. Preferably it is 99% or more.

  In addition, examples of the cyclic olefin resin used in the present invention include thermoplastic saturated norbornene resins described in paragraph Nos. [0014] to [0019] of JP-A No. 5-2108 and paragraph Nos. Of JP-A No. 2001-277430. [0015] to [0031] thermoplastic norbornene polymers, JP 2003-14901 paragraph Nos. [0008] to [0045] thermoplastic norbornene resins, JP 2003-139950 paragraph No. [0014] To [0028] norbornene-based resin composition, Japanese Patent Application Laid-Open No. 2003-161832, paragraph numbers [0029] to [0037], norbornene-based resin, Japanese Patent Application Laid-Open No. 2003-195268, paragraph numbers [0027] to [0036] The norbornene-based resin described in JP-A-2003-211589 Paragraph Nos. [0009] to [0023] alicyclic structure-containing polymer resin, norbornene polymer resin or vinyl alicyclic hydrocarbon heavy as described in paragraph Nos. [0008] to [0024] of JP-A No. 2003-111588 Examples include coalesced resins.

  Specifically, ZEONEX, ZEONOR manufactured by Nippon Zeon Co., Ltd., Arton manufactured by JSR Corporation, APPEL manufactured by Mitsui Chemicals, Inc. (APL8008T, APL6509T, APL6013T, APL5014DP, APL6015T) and the like are preferably used.

  The molecular weight of the cyclic olefin resin used in the present invention is appropriately selected according to the purpose of use, but is measured by a gel permeation chromatography method of a cyclohexane solution (a toluene solution when the polymer resin is not dissolved). When the polyisoprene or polystyrene-equivalent weight average molecular weight is usually in the range of 5,000 to 500,000, preferably 8,000 to 200,000, more preferably 10,000 to 100,000, the mechanical strength and molding processability of the molded body are high. It is preferable to be balanced.

  Moreover, when a low-volatile antioxidant is blended at a ratio of 0.01 to 5 parts by mass with respect to 100 parts by mass of the cyclic olefin-based resin, it effectively prevents the polymer from being decomposed or colored during the molding process. I can do it.

As the antioxidant, an antioxidant having a vapor pressure at 20 ° C. of 10 ⁻⁵ Pa or less, particularly preferably 10 ⁻⁸ Pa or less is desirable. Antioxidants having a vapor pressure higher than 10 ⁻⁵ Pa cause foaming during extrusion molding, and the antioxidants volatilize from the surface of the molded product when exposed to high temperatures.

  As an antioxidant which can be used by this invention, the following can be mentioned, for example, You may use 1 type in combination of these or several types.

  Hintard phenol type: 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butylphenol, 4-hydroxymethyl-2,6-di-t-butylphenol, 2,6-di -T-butyl-α-methoxy-p-dimethyl-phenol, 2,4-di-t-amylphenol, t-butyl-m-cresol, 4-t-butylphenol, styrenated phenol, 3-t-butyl- 4-hydroxyanisole, 2,4-dimethyl-6-tert-butylphenol, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3,5-di-tert-butyl-4 -Hydroxybenzylphosphonate-diethyl ester, 4,4'-bisphenol, 4,4'-bis- (2,6-di-t-butylphenol), , 2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4-methyl-6-α-methylcyclohexylphenol), 4,4'-methylene- Bis- (2-methyl-6-t-butylphenol), 4,4'-methylene-bis- (2,6-di-t-butylphenol), 1,1'-methylene-bis- (2,6-di -T-butylnaphthol), 4,4'-butylidene-bis- (2,6-di-t-butyl-meta-cresol), 2,2'-thio-bis- (4-methyl-6-t- Butylphenol), di-o-cresol sulfide, 2,2'-thio-bis- (2-methyl-6-tert-butylphenol), 4,4'-thio-bis (3-methyl-6-tert-butylphenol) 4,4'-thio-bis- (2, -Di-sec-amylphenol), 1,1'-thio-bis- (2-naphthol), 3,5-di-t-butyl-4-hydroxybenzyl ether, 1,6-hexanediol-bis- [ 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thiobis (4-methyl-6) -T-butylphenol), N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), bis (3,5-di-t-butyl-4-hydroxy) Benzylphospho Acid ethyl) calcium, 1,3,5-trimethyl-2,4,6-tris- (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, triethylene glycol-bis [3- (3- t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris -(3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxygenyl) propionate] and the like.

  Aminophenols: normal butyl-p-aminophenol, normal butyroyl-p-aminophenol, normal peragonoyl-p-aminophenol, normal lauroyl-p-aminophenol, normal stearoyl-p-aminophenol, 2,6 -Di-t-butyl-α-dimethyl, amino-p-cresol and the like.

  Hydroquinone series: hydroquinone, 2,5-di-t-butylhydroquinone, 2,5-di-t-amylhydroquinone, hydroquinone methyl ether, hydroquinone monobenzyl ether, and the like.

  Phosphite triphosphite, tris (3,4-di-t-butylphenyl) phosphite, tris (nonylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene Phosphanite, 2-ethylhexyl octyl phosphite, etc.

  Others: 2-mercaptobenzothiazole zinc salt, dicatechol borate-di-o-tolylguanidine salt, nickel-dimethyldithiocarbamate, nickel-pentamethylene dithiocarbanate, mercaptobenzimidazole, 2-mercaptobenzimidazole zinc salt and the like.

  The cyclic olefin-based resin film may contain an additive that can be generally blended into a plastic film, if necessary. Examples of such additives include heat stabilizers, light stabilizers, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, and fillers, and the content thereof is within a range that does not impair the purpose of the present invention. You can choose.

  There is no particular limitation on the method for forming the cyclic olefin-based resin film, and any of the hot melt molding method and the solution casting method can be used. The heat-melt molding method can be further classified into an extrusion molding method, a press molding method, an inflation molding method, an injection molding method, a blow molding method, a stretch molding method, etc. Among these methods, mechanical strength, surface accuracy are included. In order to obtain an excellent film, an extrusion molding method, an inflation molding method, and a press molding method are preferable, and an extrusion molding method is most preferable. The molding conditions are appropriately selected depending on the purpose of use and the molding method. In the case of the hot melt molding method, the cylinder temperature is usually in the range of 150 to 400 ° C, preferably 200 to 350 ° C, more preferably 230 to 330 ° C. Is set as appropriate. If the resin temperature is too low, fluidity will deteriorate, causing shrinkage and distortion in the film. If the resin temperature is too high, voids and silver streaks will occur due to thermal decomposition of the resin, and the film will turn yellow. Defects may occur. The thickness of the film is usually in the range of 5 to 300 μm, preferably 10 to 200 μm, more preferably 20 to 100 μm. When the thickness is too thin, handling at the time of lamination becomes difficult, and when it is too thick, the drying time after the lamination becomes long and the productivity is lowered.

  The width of the film is preferably 1.4 m or more from the viewpoint of productivity. More preferably, it is the range of 1.4-4m.

  The cyclic olefin resin film has a surface wetting tension of preferably 40 mN / m or more, more preferably 50 mN / m or more, and further preferably 55 mN / m or more. When the surface wetting tension is in the above range, the adhesive strength between the film and the polarizer is improved. In order to adjust the surface wetting tension, for example, corona discharge treatment, plasma discharge treatment, ozone spraying, ultraviolet irradiation, flame treatment, chemical treatment, and other known surface treatments can be performed.

  The sheet before stretching needs to have a thickness of about 50 to 500 μm, and the thickness unevenness is preferably as small as possible. The entire surface is within ± 8%, preferably within ± 6%, more preferably within ± 4%. is there.

  In order to make the cyclic olefin-based resin film into the retardation film according to the present invention, it is obtained by stretching the sheet at least in a uniaxial direction. In addition, it may be substantially uniaxial stretching, for example, biaxial stretching in which uniaxial stretching is performed in order to orient the molecules after stretching in a range that does not affect the molecular orientation. Biaxial stretching is preferable, and it is preferable to use the tenter device or the like for stretching.

  The draw ratio is 1.1 to 10 times, preferably 1.3 to 8 times, and a desired retardation may be set within this range. If the draw ratio is too low, the absolute value of the retardation does not increase to a predetermined value, and if it is too high, it may break.

  Stretching is usually performed in a temperature range of Tg to Tg + 50 ° C., preferably Tg to Tg + 40 ° C. of the resin constituting the sheet. If the stretching temperature is too low, it will break, and if it is too high, it will not be molecularly oriented, making it difficult to obtain the desired retardation film.

  In the film thus obtained, molecules are oriented by stretching, and a retardation having a desired size can be obtained. When used as a retardation film, preferable retardation values in the present invention are Rt of -100 to 400 nm, Ro of 20 to 300 nm, and more preferably Ro of 30 to 70 nm.

  The retardation can be controlled by the retardation of the sheet before stretching, the stretching ratio, the stretching temperature, and the thickness of the stretched oriented film. When the sheet before stretching has a certain thickness, the larger the stretching ratio, the larger the absolute value of the retardation. Therefore, by changing the stretching ratio, it is possible to obtain a retardation film having a desired retardation. I can do it.

  The retardation variation is preferably as small as possible. The retardation film generally has a retardation variation of 550 nm within ± 10 nm, preferably ± 5 nm or less, more preferably ± 1 nm or less.

  Variations in thickness and thickness unevenness within the retardation can be reduced by using these small unstretched sheets, and by applying stress evenly to the sheets during stretching. For this purpose, it is desirable to stretch in a controlled temperature environment under a uniform temperature distribution, preferably within ± 5 ° C., more preferably within ± 2 ° C., particularly preferably within ± 0.5 ° C.

(Optically anisotropic layer)
The retardation film according to the present invention preferably has an optically anisotropic layer.

  The optically anisotropic layer is a rod-like liquid crystalline compound or a polymerization initiator or an optional additive described later (eg, plasticizer, monomer, surfactant, cellulose ester, 1,3,5-triazine compound, chiral agent). It can form by apply | coating the liquid crystal composition (coating liquid) containing this on an alignment film.

  On the other hand, examples of using a discotic liquid crystal compound include C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives described in C.I. Destrade et al., Mol. Cryst. 122, 141 (1985), Physics lett, A, 78, 82 (1990); Kohne et al., Angew. Chem. 96, page 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. , 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, page 2655 (1994), and azacrown and phenylacetylene macrocycles. Furthermore, the discotic liquid crystalline compounds generally have a structure in which these are used as the mother nucleus at the center of the molecule, and linear alkyl groups, alkoxy groups, substituted benzoyloxy groups, etc. are radially substituted as the linear chains. Is also included and exhibits liquid crystallinity. However, the molecule itself is not limited to these as long as it has negative uniaxiality and can give a certain orientation. Further, in the present invention, the optically anisotropic layer formed from the discotic liquid crystalline compound does not need to be a final product, for example, a low molecular discotic liquid crystalline compound is heated, It includes a group that reacts with light or the like, and as a result, is polymerized or cross-linked by reaction with heat, light, or the like, resulting in high molecular weight and loss of liquid crystallinity. Preferred examples of the discotic liquid crystalline compound are described in JP-A-8-50206. The polymerization of the discotic liquid crystalline compound is described in JP-A-8-27284.

  In order to fix the discotic liquid crystalline compound by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline compound. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Therefore, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following general formula (1).

General formula (1) D (-LP) n
Where D is a discotic core; L is a divalent linking group, P is a polymerizable group, and n is an integer from 4-12. An example of the disk-shaped core (D) is shown below. In each of the following examples, LP (or PL) means a combination of a divalent linking group (L) and a polymerizable group (P).

  In the general formula (1), the divalent linking group (L) is selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —CO—, —NH—, —O—, —S—, and combinations thereof. It is preferable that it is a bivalent coupling group. The divalent linking group (L) is a divalent group in which at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, —CO—, —NH—, —O—, and —S— are combined. More preferably, it is a linking group. The divalent linking group (L) is most preferably a divalent linking group in which at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO- and -O- are combined. . The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The number of carbon atoms in the arylene group is preferably 6-10.

  Examples of the divalent linking group (L) are shown below. The left side is bonded to the discotic core (D), and the right side is bonded to the polymerizable group (P). AL represents an alkylene group or an alkenylene group, and AR represents an arylene group. The alkylene group, alkenylene group and arylene group may have a substituent (eg, an alkyl group).

L1: -AL-CO-O-AL-
L2: -AL-CO-O-AL-O-
L3: -AL-CO-O-AL-O-AL-
L4: -AL-CO-O-AL-O-CO-
L5: -CO-AR-O-AL-
L6: -CO-AR-O-AL-O-
L7: -CO-AR-O-AL-O-CO-
L8: -CO-NH-AL-
L9: -NH-AL-O-
L10: -NH-AL-O-CO-
L11: -O-AL-
L12: -O-AL-O-
L13: -O-AL-O-CO-
L14: -O-AL-O-CO-NH-AL-
L15: -O-AL-S-AL-
L16: -O-CO-AR-O-AL-CO-
L17: -O-CO-AR-O-AL-O-CO-
L18: -O-CO-AR-O-AL-O-AL-O-CO-
L19: -O-CO-AR-O-AL-O-AL-O-AL-O-CO-
L20: -S-AL-
L21: -S-AL-O-
L22: -S-AL-O-CO-
L23: -S-AL-S-AL-
L24: -S-AR-AL-
The polymerizable group (P) of the general formula (1) is determined according to the type of polymerization reaction. Examples of the polymerizable group (P) are shown below.

  The polymerizable group (P) is preferably an unsaturated polymerizable group (P1, P2, P3, P7, P8, P15, P16, P17) or an epoxy group (P6, P18). More preferably, it is most preferably an ethylenically unsaturated polymerizable group (P1, P7, P8, P15, P16, P17). In General formula (1), n is an integer of 4-12. A specific number is determined according to the type of the disk-shaped core (D). In addition, although the combination of several L and P may differ, it is preferable that it is the same.

  When the discotic liquid crystalline compound is used, the optically anisotropic layer is a layer having negative birefringence, and the surface of the discotic structural unit is inclined with respect to the surface of the cellulose acetate film and the discotic structural unit. The angle formed between the surface and the surface of the cellulose acetate film is preferably changed in the depth direction of the optically anisotropic layer.

  The surface angle (tilt angle) of the disk-like structural unit generally increases or decreases in the depth direction of the optically anisotropic layer and with an increase in the distance from the bottom surface of the optically anisotropic layer. The tilt angle preferably increases with increasing distance. Further, the change in the inclination angle includes continuous increase, continuous decrease, intermittent increase, intermittent decrease, change including continuous increase and continuous decrease, and intermittent change including increase and decrease. I can do it. The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction. Even if the tilt angle includes a region where the tilt angle does not change, the tilt angle preferably increases or decreases as a whole. Further, it is preferable that the inclination angle increases as a whole, and it is particularly preferable that the inclination angle changes continuously.

  The tilt angle of the disk-shaped unit on the support side can be adjusted by selecting a disk-shaped liquid crystalline compound or a material for the alignment film, or by selecting a rubbing treatment method. In addition, the inclination angle of the disk-like unit on the surface side (air side) can be adjusted by selecting a discotic liquid crystalline compound or another compound used together with the discotic liquid crystalline compound. Examples of the compound used together with the discotic liquid crystalline compound include a plasticizer, a surfactant, a polymerizable monomer and a polymer. Further, the degree of change in the tilt angle can be adjusted by the same selection as described above.

  The plasticizer, surfactant, and polymerizable monomer used together with the discotic liquid crystalline compound are compatible with the discotic liquid crystalline compound and can change the tilt angle of the discotic liquid crystalline compound or can be aligned. Any compound can be used as long as it does not inhibit the above. Among these, polymerizable monomers (eg, compounds having a vinyl group, a vinyloxy group, an acryloyl group, and a methacryloyl group) are preferable. The amount of the compound added is generally in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass with respect to the discotic liquid crystalline compound.

  As the polymer used together with the discotic liquid crystalline compound, any polymer can be used as long as it is compatible with the discotic liquid crystalline compound and can change the tilt angle of the discotic liquid crystalline compound. A cellulose ester can be mentioned as an example of a polymer. Preferred examples of the cellulose ester include cellulose acetate, cellulose acetate propionate, hydroxypropyl cellulose, and cellulose acetate butyrate. In order not to inhibit the orientation of the discotic liquid crystalline compound, the amount of the polymer added is generally in the range of 0.1 to 10% by mass with respect to the discotic liquid crystalline compound, and in the range of 0.1 to 8% by mass. It is more preferable that it is in the range of 0.1 to 5% by mass.

  The optically anisotropic layer is generally formed by applying a solution obtained by dissolving a discotic liquid crystalline compound and other compounds in a solvent onto an alignment film, drying it, and then heating it to a discotic nematic phase formation temperature, and then aligning it (disco It can be obtained by cooling while maintaining the (tick nematic phase). Alternatively, the optically anisotropic layer is formed by applying a solution obtained by dissolving a discotic liquid crystalline compound and another compound (for example, a polymerizable monomer, a photopolymerization initiator) in a solvent onto the alignment film, and then drying it. It is obtained by heating to a discotic nematic phase formation temperature, polymerizing (by irradiation with UV light, etc.), and further cooling. The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline compound used in the present invention is preferably 70 to 300 ° C, particularly preferably 70 to 170 ° C.

(Hard coat layer)
In the polarizing plate protective film of the present invention, a hard coat layer can be coated on the substrate film. A method for producing an actinic radiation curable resin layer used as a hard coat layer will be described.

  In the polarizing plate protective film of the present invention, an active ray curable resin layer is preferably used as the hard coat layer.

  The actinic radiation curable resin layer refers to a layer mainly composed of a resin that cures through a crosslinking reaction or the like by irradiation with actinic rays such as ultraviolet rays or electron beams. As the actinic radiation curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and a hard coat layer is formed by curing by irradiation with actinic radiation such as ultraviolet rays or electron beams. Typical examples of the actinic radiation curable resin include an ultraviolet curable resin and an electron beam curable resin, and a resin curable by ultraviolet irradiation is preferable.

  As the ultraviolet curable resin, for example, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, or an ultraviolet curable epoxy resin is preferable. Used.

  UV curable acrylic urethane resins generally include 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter referred to as acrylates) in products obtained by reacting polyester polyols with isocyanate monomers or prepolymers. 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-A-59-151110 can be used.

  For example, a mixture of 100 parts Unidic 17-806 (Dainippon Ink Co., Ltd.) and 1 part Coronate L (Nihon Polyurethane Co., Ltd.) is preferably used.

  Examples of UV curable polyester acrylate resins include those that are easily formed when 2-hydroxyethyl acrylate and 2-hydroxy acrylate monomers are generally reacted with polyester polyols. JP-A-59-151112 Can be used.

  Specific examples of the ultraviolet curable epoxy acrylate resin include an epoxy acrylate as an oligomer, a reactive diluent and a photoreaction initiator added thereto, and reacted to form an oligomer. The thing as described in 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. I can list them.

  Specific examples of the photoreaction initiator of these ultraviolet curable resins include benzoin and its derivatives, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof. You may use with a photosensitizer. The photoinitiator can also be used as a photosensitizer. In addition, when using an epoxy acrylate photoinitiator, a sensitizer such as n-butylamine, triethylamine, or tri-n-butylphosphine can be used. The photoreaction initiator or photosensitizer used in the ultraviolet curable resin composition is 0.1 to 15 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the composition.

  Examples of the resin monomer include general monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, cyclohexyl acrylate, vinyl acetate, and styrene as monomers having one unsaturated double bond. In addition, monomers having two or more unsaturated double bonds include ethylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, 1,4-cyclohexane diacrylate, 1,4-cyclohexyldimethyl adiacrylate, and the above trimethylolpropane. Examples thereof include triacrylate and pentaerythritol tetraacryl ester.

  Examples of commercially available ultraviolet curable resins that can be used in the present invention include ADEKA OPTMER KR / BY series: KR-400, KR-410, KR-550, KR-566, KR-567, BY-320B (Asahi Denka ( Co., Ltd.); Koeihard 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, KRM7039, KRM7130, KRM7131, UVECRYL29201, UVECRYL29202 (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.), etc. Can be selected as appropriate.

  Specific examples of compounds include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate, and the like. .

  These actinic ray curable resin layers can be coated by a known method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, or an ink jet method.

As a light source for curing an ultraviolet curable resin by a photocuring reaction to form a cured coating layer, any light source that generates ultraviolet rays can be used without any 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 preferably 5 to 150 mJ / cm ² , particularly preferably 20 to 100 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 the tension is not particularly limited, and the tension may be applied in the conveying direction on the back roll, or the tension may be applied in the width direction or the biaxial direction by a tenter. This makes it possible to obtain a film having further excellent flatness.

  Examples of the organic solvent for the UV curable resin layer composition coating solution include hydrocarbons (toluene, xylene), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol), ketones (acetone, methyl ethyl ketone, methyl isobutyl). Ketone), esters (methyl acetate, ethyl acetate, methyl lactate), glycol ethers, other organic solvents, or a mixture thereof. Propylene glycol monoalkyl ether (1 to 4 carbon atoms of the alkyl group) or propylene glycol monoalkyl ether acetate ester (1 to 4 carbon atoms of the alkyl group) is 5% by mass or more, more preferably 5 to 80%. It is preferable to use the organic solvent containing at least mass%.

  In addition, it is particularly preferable to add a silicon compound to the ultraviolet curable resin layer composition coating solution. For example, polyether-modified silicone oil is preferably added. The number average molecular weight of the polyether-modified silicone oil is, for example, 1000 to 100000, preferably 2000 to 50000. If the number average molecular weight is less than 1000, the drying property of the coating film decreases, and conversely, the number average When the molecular weight exceeds 100,000, it tends to be difficult to bleed out to the coating surface.

  Commercially available silicon compounds include DKQ8-779 (trade name, manufactured by Dow Corning), SF3771, SF8410, SF8411, SF8419, SF8421, SF8428, SH200, SH510, SH1107, SH3749, SH3771, BX16-034, SH3746, SH3749, SH8400, SH3771M, SH3772M, SH3773M, SH3775M, BY-16-837, BY-16-839, BY-16-869, BY-16-870, BY-16-004, BY-16-891, BY-16 872, BY-16-874, BY22-008M, BY22-012M, FS-1265 (above, product names manufactured by Toray Dow Corning Silicone), KF-101, KF-100T, KF351, KF3 2, KF353, KF354, KF355, KF615, KF618, KF945, KF6004, Silicone X-22-945, X22-160AS (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), XF3940, XF3949 (trade name, manufactured by Toshiba Silicone Co., Ltd.) ), Disparon LS-009 (manufactured by Enomoto Kasei Co., Ltd.), Granol 410 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.), TSF4440, TSF4441, TSF4445, TSF4446, TSF4452, TSF4460 (manufactured by GE Toshiba Silicone), BYK-306, BYK- 330, BYK-307, BYK-341, BYK-344, BYK-361 (manufactured by BYK-Japan) L series (for example, L7001, L-7006, L-7604, L-9000) manufactured by Nippon Unicar Co., Ltd. Y Over's, FZ series (FZ-2203, FZ-2206, FZ-2207) and the like, are preferably used.

  These components enhance the applicability to the substrate and the lower layer. When added to the outermost surface layer of the laminate, it not only improves the water repellency, oil repellency and antifouling properties of the coating film, but also exhibits an effect on the scratch resistance of the surface. These components are preferably added in a range of 0.01 to 3% by mass with respect to the solid component in the coating solution.

  As a coating method of the ultraviolet curable resin composition coating solution, the above-described methods can be used. The coating amount is suitably 0.1 to 30 μm, preferably 0.5 to 15 μm, as the wet film thickness. The dry film thickness is 0.1 to 20 μm, preferably 1 to 10 μm.

The ultraviolet curable resin composition is preferably irradiated with ultraviolet rays during or after coating and drying, and the irradiation time for obtaining the active ray irradiation amount of 5 to 150 mJ / cm ² is from 0.1 seconds to 5 seconds. Minutes are good, and 0.1 to 10 seconds is more preferable from the viewpoint of curing efficiency or work efficiency of the ultraviolet curable resin.

Moreover, it is preferable that the illuminance of these active ray irradiation parts is 50-150 mW / cm < ² >.

  In order to prevent blocking, to improve scratch resistance, to give antiglare property or light diffusibility, and to adjust the refractive index in the cured resin layer thus obtained, fine particles of an inorganic compound or an organic compound Can also be added.

  Examples of inorganic fine particles used in the hard coat layer include silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, silicic acid. Mention may be made of aluminum, magnesium silicate and calcium phosphate. In particular, silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide and the like are preferably used.

  The organic fine 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. Polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, or polyfluoroethylene resin powder can be added to the ultraviolet curable resin composition. Particularly preferred are cross-linked polystyrene particles (for example, SX-130H, SX-200H, SX-350H, manufactured by Soken Chemical) and polymethyl methacrylate-based particles (for example, MX150, MX300, manufactured by Soken Chemical).

  The average particle diameter of these fine particle powders is preferably 0.005 to 5 μm, and particularly preferably 0.01 to 1 μm. As for the ratio of a ultraviolet curable resin composition and fine particle powder, it is desirable to mix | blend so that it may be 0.1-30 mass parts with respect to 100 mass parts of resin compositions.

  The ultraviolet curable resin layer is a clear hard coat layer having a center line average roughness (Ra) defined by JIS B 0601 of 1 to 50 nm or an antiglare layer having an Ra of about 0.1 to 1 μm. Is preferred. The center line average roughness (Ra) is preferably measured with an optical interference type surface roughness measuring instrument, and can be measured using, for example, RST / PLUS manufactured by WYKO.

(Antireflection layer)
An antireflection layer may be further provided on the polarizing plate protective film having the hard coat layer according to the present invention to form an antireflection film. Moreover, this film can be bonded to the position fixing holding plate to give an antireflection function to the position fixing holding plate. Furthermore, it is also preferable to provide an antireflection layer directly on the position fixing holding plate.

  The antireflection layer applicable to the present invention preferably comprises a plurality of refractive index layers provided on the hard coat layer from the hard coat layer side, and further comprises a high refractive index layer and a low refractive index layer laminated in this order. Preferably there is. The level of refractive index is largely determined by the metal or compound contained therein, for example, Ti is high, Si is low, F-containing compounds are further low, and the refractive index is set by such a combination. The refractive index and the film thickness can be calculated and calculated by measuring the spectral reflectance.

  In the antireflection film of the present invention, each antireflection layer is preferably laminated in consideration of the refractive index, the film thickness, the number of layers, the layer order, and the like so that the reflectance is reduced by optical interference. The antireflection layer is formed by combining a high refractive index layer having a higher refractive index than that of the support and a low refractive index layer having a lower refractive index than that of the support. Particularly preferably, it is an antireflection layer composed of three or more refractive index layers, three layers having different refractive indexes from the support side, a medium refractive index layer (having a higher refractive index than the support or hard coat layer, Layers having a refractive index lower than that of the high refractive index layer) / high refractive index layer / low refractive index layer are preferably used in this order. Alternatively, an antireflection layer having a layer structure of four or more layers in which two or more high refractive index layers and two or more low refractive index layers are alternately laminated is also preferably used.

  In addition, if necessary, it is also preferable to further provide an antifouling layer on the outermost low refractive index layer so that dirt and fingerprints can be easily wiped off. As the antifouling layer, a fluorine-containing organosilane compound is preferably used.

The antireflection layer applicable to the present invention can be formed by a coating method, and can be formed by a metal oxide layer, a metal oxynitride layer (SiO ₂ , TiO ₂ , Ta ₂₎ by a dry process such as atmospheric pressure plasma treatment or CVD. _{O 5, ZrO 2, ZnO,} SnO 2, ITO, SiN, TiN, SiO x N y, SiO x, TiO x, such as TiO _x N _y) can be provided. In the present invention, it is preferable to form the antireflection layer by a coating method.

  In the present invention, the high refractive index layer preferably contains titanium oxide. These are layers having a refractive index of 1.55 to 2.5 formed by applying and drying a coating liquid containing fine particles, monomers of organic titanium compounds, oligomers or hydrolysates thereof.

Examples of the monomer or oligomer of the organic titanium compound used in the present invention include Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti (On-C ₃ H ₇ ) ₄ , Ti (O-i- _{C 3 H 7) 4, Ti} (O-n-C 4 H 9) 4, Ti (O-n-C 3 H 7) 4 2-10 mer, Ti (O-i-C 3 H 7) Preferred examples include ₄ to 10 mer of ₄ and 2 to 10 mer of Ti (On-C ₄ H ₉ ) ₄ . These may be used alone or in combination of two or more. Of these _{Ti (O-n-C 3} H 7) 4, Ti (O-i-C 3 H 7) 4, Ti (O-n-C 4 H 9) 4, Ti (O-n-C 3 H 7 ) ₄ to 10-mer and Ti (On-C ₄ H ₉ ) ₄ to 10-mer are particularly preferable.

  The monomer, oligomer or hydrolyzate of the organic titanium compound used in the present invention preferably occupies 50.0% by mass to 98.0% by mass in the solid content contained in the coating solution. The solid content ratio is more preferably 50% by mass to 90% by mass, and further preferably 55% by mass to 90% by mass. In addition, it is also preferable to add a polymer of an organic titanium compound (a product obtained by previously hydrolyzing an organic titanium compound to be crosslinked) or titanium oxide fine particles to the coating composition.

  Further, in the present invention, the coating liquid contains the above-mentioned organotitanium compound monomer, oligomer part or complete hydrolyzate, but the organotitanium compound monomer and oligomer are self-condensed, crosslinked and network-bonded. is there. Catalysts and curing agents can be used to accelerate the reaction, including metal chelate compounds, organometallic compounds such as organic carboxylates, organosilicon compounds having amino groups, and acid generation by light. Agent (photoacid generator). Of these catalysts or curing agents, an aluminum chelate compound and a photoacid generator are particularly preferred. Examples of aluminum chelate compounds are ethyl acetoacetate aluminum diisopropylate, aluminum trisethyl acetoacetate, alkyl acetoacetate aluminum diisopropylate, aluminum monoacetylacetonate bisethylacetoacetate, aluminum trisacetylacetonate, etc. Examples of the acid generator include benzyltriphenylphosphonium hexafluorophosphate, other phosphonium salts, and triphenylphosphonium hexafluorophosphate salts.

  It is preferable that 0.5 mass%-20 mass% of binder is contained as a solid content ratio in the coating liquid of an antireflection layer.

  As a binder, it is a coating layer having two or more polymerizable groups such as a polymerizable vinyl group, allyl group, acryloyl group, methacryloyl group, isopropenyl group, epoxy group, oxetane ring, and containing an actinic radiation curable resin. The same acrylic or methacrylic active energy ray reactive compound, epoxy active energy ray reactive compound, or oxetane active energy ray reactive compound as used can be used. These compounds include monomers, oligomers and polymers. Of these active groups, an acryloyl group, a methacryloyl group or an epoxy group is preferable from the viewpoint of polymerization rate and reactivity, and a polyfunctional monomer or oligomer is more preferable. Moreover, the actinic radiation curable resin used for the coating layer and hard-coat layer containing the above-mentioned actinic radiation curable resin can also be used preferably. Furthermore, an alcohol-soluble acrylic resin is also preferably used.

  Among the titanium compounds, an alcohol-soluble acrylic resin is also preferably used as the binder for the high refractive index layer, whereby a high refractive index layer can be obtained with little film thickness unevenness. Specifically, an alkyl (meth) acrylate polymer or an alkyl (meth) acrylate copolymer, for example, a copolymer such as n-butyl methacrylate, isobutyl methacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, is preferably used. The copolymer component is not limited to these. Commercially available products include Dianal BR-50, BR-51, BR-52, BR-60, BR-64, BR-65, BR-70, BR-73, BR-75, BR-76, BR-77. , BR-79, BR-80, BR-82, BR-83, BR-85, BR-87, BR-88, BR-89, BR-90, BR-93, BR-95, BR-96, BR -100, BR-101, BR-102, BR-105, BR-107, BR-108, BR-112, BR-113, BR-115, BR-116, BR-117, BR-118 (above, Mitsubishi Can be used. These monomer components can also be added as a binder for the medium to high refractive index layer. The refractive index can be adjusted by changing the addition ratio of the binder.

  The low refractive index layer used in the present invention is preferably provided by coating silicon compound fine particles such as silicon oxide or fluorine-containing compound fine particles. Examples of preferable organosilicon compounds include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and the like. An oligomer is obtained. The hydrolysis reaction can be carried out by a known method. For example, a predetermined amount of water is added to the tetraalkoxysilane, and the by-product alcohol is distilled off in the presence of an acid catalyst. React at 100 ° C. By this reaction, the alkoxysilane is hydrolyzed, followed by a condensation reaction, and a liquid silicate oligomer having two or more hydroxyl groups (usually an average degree of polymerization of 2 to 8, preferably 3 to 6) is used as a hydrolyzate. Can be obtained.

  Examples of the curing catalyst include acids, alkalis, organic metals, metal alkoxides and the like. In the present invention, acids, particularly organic acids having a sulfonyl group or a carboxyl group are preferably used. For example, acetic acid, polyacrylic acid, benzenesulfonic acid, p-toluenesulfonic acid, methylsulfonic acid and the like are used. The organic acid is more preferably a compound having a hydroxyl group and a carboxyl group in one molecule. For example, a hydroxydicarboxylic acid such as citric acid or tartaric acid is used. The organic acid is more preferably a water-soluble acid. For example, in addition to the citric acid and tartaric acid, levulinic acid, formic acid, propionic acid, malic acid, succinic acid, methyl succinic acid, fumaric acid, oxaloacetic acid, pyruvin. Acid, 2-oxoglutaric acid, glycolic acid, D-glyceric acid, D-gluconic acid, malonic acid, maleic acid, oxalic acid, isocitric acid, lactic acid and the like are preferably used. Also, benzoic acid, hydroxybenzoic acid, atorvaic acid and the like can be used as appropriate.

  By using the above-mentioned organic acids, not only can the piping corrosion and safety concerns during production due to the use of inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, hypochlorous acid, and boric acid be eliminated, but also during hydrolysis. A stable hydrolyzate can be obtained without causing gelation. The addition amount is 0.1 to 10 parts by mass, preferably 0.2 to 5 parts by mass with respect to 100 parts by mass of the partial hydrolyzate. In addition, the amount of water added may be equal to or greater than the amount that the partial hydrolyzate can theoretically hydrolyze to 100%, and an amount equivalent to 100 to 300%, preferably an amount equivalent to 100 to 200% is added.

  The coating composition for the low refractive index layer thus obtained is extremely stable.

  Further, in the present invention, the aging step sufficiently proceeds the hydrolysis and condensation of the organosilicon compound, and the resulting film has excellent properties. For the aging, the oligomer liquid may be allowed to stand, and the standing time is a time for which the above-described crosslinking proceeds to a degree sufficient to obtain desired film characteristics. Specifically, although it depends on the type of catalyst used, it is sufficient for hydrochloric acid to be 1 hour or more at room temperature, for maleic acid to be several hours or more, and about 8 hours to 1 week, usually around 3 days. The ripening temperature affects the ripening time, and it may be better to take a means of heating to around 20 ° C. in extremely cold regions. In general, ripening progresses quickly at high temperatures, but when heated to 100 ° C. or higher, gelation occurs. Therefore, heating to 50 to 60 ° C. at best is appropriate. In addition to the above, the silicate oligomer used in the present invention is a modified product modified with an organic compound (monomer, oligomer, polymer) having a functional group such as an epoxy group, an amino group, an isocyanate group, or a carboxyl group. It may be present alone or in combination with the above silicate oligomer.

  In the present invention, silicon oxide fine particles can be contained in the low refractive index layer. It is preferable to include silicon oxide fine particles having a particle size of 0.1 μm or less. For example, Aerosil 200V (manufactured by Nippon Aerosil Co., Ltd.) or the like can be added. In particular, silicon oxide fine particles whose surface is modified with an alkyl group are preferably used. For example, silicon oxide fine particles whose surface is modified with a methyl group are commercially available as Aerosil R972 and R972V (manufactured by Nippon Aerosil Co., Ltd.). Can be added. In addition, it is also possible to use silicon oxide fine particles whose surface is substituted with an alkyl group as described in JP-A-2001-2799, and it is easy to treat with an alkylsilane coupling agent after hydrolysis of the silicate oligomer. Can be obtained. As an addition amount, it is preferable to add so that it may become the range of 0.1 mass%-40 mass% in the solid content ratio in a low-refractive-index layer.

  Further, in the present invention, hollow spherical silica-based fine particles having an outer shell layer and having a porous or hollow inside, as described in JP-A Nos. 2001-167737, 2001-233611, 2002-79616, etc. It is also preferable to use. The hollow spherical fine particles are (I) a composite particle comprising a porous particle and a coating layer provided on the surface of the porous particle, or (II) a cavity inside, and the content is a solvent, gas or porous Cavity particles filled with a substance. The low refractive index layer may contain either (I) composite particles or (II) hollow particles, or may contain both.

  The hollow particles are particles having cavities inside, and the cavities are surrounded by particle walls. 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 diameter of such hollow spherical fine particles is in the range of 5 to 300 nm, preferably 10 to 200 nm.

  A silane compound can be further added to each refractive index layer of the present invention in order to adjust the refractive index or improve the film quality.

  Solvents used in the coating solution for coating the high, medium and low refractive index layers used in the present invention are alcohols such as methanol, ethanol, 1-propanol, 2-propanol and butanol; acetone, methyl ethyl ketone, cyclohexanone Ketones such as: Aromatic hydrocarbons such as benzene, toluene, xylene; Glycols such as ethylene glycol, propylene glycol, hexylene glycol; Ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, diethyl cell Glycol ethers such as sorb, diethyl carbitol, propylene glycol monomethyl ether; N-methylpyrrolidone, dimethylformamide, methyl lactate, ethyl lactate, water, etc. are used, and these should be used alone or in combination of two or more. Can.

  Further, those having an ether bond in the molecule are particularly preferred, and glycol ethers are more preferred.

  Examples of glycol ethers include propylene glycol mono (C1-C4) alkyl ether and propylene glycol mono (C1-C4) alkyl ether ester, specifically, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether, propylene Examples thereof include glycol mono n-propyl ether, propylene glycol monoisopropyl ether, propylene glycol monobutyl ether and the like. Examples of the propylene glycol mono (C1 to C4) alkyl ether ester include propylene glycol monoalkyl ether acetate, and specific examples include propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate. These solvents are preferably added in an amount of 1% to 90% by mass of the total organic solvent in the coating solution.

  Various additives can be added to the coating solution for each of the high, medium and low refractive index layers used in the present invention.

  For example, it is preferable to add a slipping agent to the low refractive index layer, and scratch resistance can be improved by imparting slipperiness. As the slip agent, silicon oil or a wax-like substance is preferably used.

  Specifically, higher fatty acids such as behenic acid, stearamide, and pentacoic acid, or derivatives thereof, and carnauba wax, beeswax, and montan wax containing many of these components as natural products can also be preferably used. Polyorganosiloxanes as disclosed in Japanese Patent Publication No. 53-292, higher fatty acid amides as disclosed in US Pat. No. 4,275,146, Japanese Patent Publication No. 58-33541, British Patent No. 927,446 Higher fatty acid esters (esters of fatty acids having 10 to 24 carbon atoms and alcohols having 10 to 24 carbon atoms), and U.S. Patents, as disclosed in JP-A-55-126238 and 58-90633 From higher fatty acid metal salts as disclosed in US Pat. No. 3,933,516, and dicarboxylic acids having up to 10 carbon atoms and aliphatic or cycloaliphatic diols as disclosed in JP-A-51-37217. Polyester compounds, and oligopolyesters from dicarboxylic acids and diols disclosed in JP-A-7-13292 Can.

The addition amount of the slip agent used in the low refractive index layer is preferably ^{0.01mg / m 2 ~10mg / m 2} . If necessary, it can be added to the middle refractive index layer or the high refractive index layer.

  Among the high refractive index layer and the low refractive index layer used in the present invention, it is preferable to add a surfactant, a softening agent, a softening smoothing agent, etc., thereby improving the scratch resistance. Among these, anionic or nonionic surfactants are preferable, and for example, dialkylsulfosuccinic acid sodium salt, nonionic surfactant emulsion of polyhydric alcohol fatty acid ester, and the like are preferable. For example, lipooil NT-6, NT12, NT-33, TC-1, TC-68, TC-78, CW-6, TCF-208, TCF-608, NK oil CS-11, AW-9, AW-10 , AW-20, polysofter N-606, paint additive PC-700 (manufactured by Nikka Chemical Co., Ltd.) and the like are used.

  Among the materials used in the present invention, it is preferable to irradiate actinic rays after the coating of the high refractive index layer and the low refractive index layer in order to promote hydrolysis or curing of the composition containing the metal alkoxide. More preferably, the active energy ray is irradiated every time each layer is coated.

The actinic radiation used in the present invention can use the same light source as that used for curing the actinic radiation curable resin layer. Irradiation conditions vary depending on individual lamps, irradiation dose is preferably ^{20mJ / cm 2 ~10000mJ / cm 2} , more preferably from ^{100mJ / cm 2 ~2000mJ / cm 2} , particularly preferably 400 mJ / cm ² ~ 2000 mJ / cm ² .

  When ultraviolet rays are used, the multilayer antireflection layer may be irradiated one by one or after lamination, but it is particularly preferable to irradiate the ultraviolet rays after the multilayers are laminated.

  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 polarizing plate>
A polyvinyl alcohol film having a thickness of 120 μm was uniaxially stretched (temperature: 110 ° C., stretch ratio: 5 times). This was immersed in an aqueous solution composed of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 68 ° C. composed of 6 g of potassium iodide, 7.5 g of boric acid and 100 g of water. This was washed with water and dried to obtain a polarizing film.

  Next, as a polarizing film and a polarizing plate protective film according to the following steps 1 to 5, Konica Minolta Op KC8UXW-H (polarizing plate protective film with hard coat) and Konica Minolta Tack KC8UCR4 (retardation film) are manufactured as Konica Minolta Opto Co., Ltd. A polarizing plate was used. The retardation of each film is as follows.

KC8UXW-H: Ro = 5 nm, Rt = 45 nm
KC8UCR4: Ro = 50 nm, Rt = 130 nm
The measurement measured the average refractive index of the film constituent material using an Abbe refractometer (4T). Moreover, the thickness of the film was measured using a commercially available micrometer. Using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments), film retardation measurement at a wavelength of 590 nm was performed under the same environment for 24 hours in an environment of 23 ° C. and 55% RH. went.

  Step 1: The polarizing plate protective film was immersed in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried to obtain a saponified cellulose ester film.

  Step 2: The polarizing film was immersed in a polyvinyl alcohol adhesive tank having a solid content of 2% by mass for 1 to 2 seconds.

  Step 3: Excess adhesive adhered to the polarizing film in Step 2 was lightly wiped off and placed so as to be sandwiched between the two polarizing plate protective films saponified in Step 1. At that time, lamination was performed so that the hard coat layer was on the outside.

Step 4: pressure 20-30 N / cm ² the laminated film sample in step 3, the conveying speed was pasted at approximately 2m / min.

  Process 5: The sample bonded in the process 4 in an 80 ° C. dryer was dried to obtain a polarizing plate.

<Production of Liquid Crystal Display Device 1: Comparative Example>
A liquid crystal panel for viewing angle measurement was produced as follows, and the characteristics as a liquid crystal display device were evaluated.

  Carefully peel off the polarizing plate on both the observation surface side and the backlight surface side of the commercially available 32-inch liquid crystal TV (MVA type liquid crystal cell, using a direct backlight) in advance, and the retardation of the produced polarizing plate. The following adhesive layer was provided on the film side surface, and each was bonded to the glass surface of the liquid crystal cell.

  At that time, the direction of bonding of the polarizing plate was performed so that the absorption axis was in the same direction as the polarizing plate bonded in advance, and the liquid crystal display device 1 was produced.

(Adhesive layer)
The main component (part number: EL-436A, manufactured by Toyo Morton Co., Ltd.) and a curing agent (part number: EL-436B, manufactured by Toyo Morton Co., Ltd.) of a two-component water-based urethane adhesive are blended at 10: 3, and 10 with ion-exchanged water. A pressure-sensitive adhesive composition was prepared by diluting to a mass%, and applied at a thickness of 10 μm by an ink jet method. The storage elastic modulus of the adhesive layer I at 25 ° C. was 8.0 × 10 ⁶ Pa.

<Production of liquid crystal display device 2>
The adhesive layer was provided on the surface of the polarizing plate protective film with a hard coat of the polarizing plate on the observation surface side and adhered to the glass plate, and the retardation film side was disposed and assembled so as not to adhere to the liquid crystal cell. Further, the polarizing plate on the backlight surface side was bonded to the liquid crystal cell through an adhesive layer in the same manner as the liquid crystal display device 1.

<Production of liquid crystal display device 3>
In the liquid crystal display device 2, a liquid crystal display device 3 was produced in the same manner except that a gas layer having a thickness of 10 nm was provided as a dynamic medium layer between the retardation film of the polarizing plate on the observation surface side and the liquid crystal cell.

<Production of liquid crystal display device 4>
In the liquid crystal display device 3, the polarizing plate on the backlight side is similarly provided with a 10 nm thick gas layer as a dynamic medium layer between the retardation film and the liquid crystal cell, and the retardation film is disposed. The said adhesion layer was provided in the surface of the polarizing plate protective film of the opposite surface, and it adhered to the glass plate, and the liquid crystal display device 4 was produced.

  After the produced liquid crystal display devices 1 to 4 were stored at 60 ° C. and 90% RH for 1500 hours, the liquid crystal display device was turned on, and the presence or absence of light leakage in the black display was confirmed after 6 hours. Evaluation was performed according to the following criteria, and the results are shown in Table 1.

  A: No light leakage in the vicinity is observed.

  ○: Light leakage in the surrounding area is hardly an issue.

  Δ: Peripheral light leakage is observed.

  ×: Significant light leakage around

  From the above table, it was found that the liquid crystal display devices 2 to 4 having the configuration of the present invention have significantly improved peripheral light leakage.

Example 2
A polarizing plate was produced in the same manner as in Example 1 except that the following cyclic olefin-based resin film was used instead of Konica Milnotac KC8UCR4 (retardation film) in Example 1, and then the liquid crystal display device 5 ( Comparative Example) and liquid crystal display devices 6 to 8 (present invention) were produced.

<< Production of Cyclic Olefin Resin Film >>
In a nitrogen atmosphere, 500 parts of dehydrated cyclohexane, 1.2 parts of 1-hexene, 0.15 part of dibutyl ether, and 0.30 part of triisobutylaluminum were mixed in a reactor at room temperature, and then kept at 45 ° C. 20 parts of tricyclo [4.3.0.12,5] deca-3,7-diene (dicyclopentadiene, hereinafter abbreviated as DCP), 1,4-methano-1,4,4a, 9a-tetrahydrofluorene ( Hereinafter, a norbornene-based monomer comprising 140 parts of MTF) and 40 parts of 8-methyl-tetracyclo [4.4.0.12, 5.17,10] -dodec-3-ene (hereinafter abbreviated as MTD). The mixture and 40 parts of tungsten hexachloride (0.7% toluene solution) were continuously added over 2 hours for polymerization. To the polymerization solution, 1.06 part of butyl glycidyl ether and 0.52 part of isopropyl alcohol were added to deactivate the polymerization catalyst and stop the polymerization reaction.

  Next, 270 parts of cyclohexane is added to 100 parts of the reaction solution containing the obtained ring-opening polymer, and 5 parts of a nickel-alumina catalyst (manufactured by JGC Chemical Co., Ltd.) is added as a hydrogenation catalyst, and the pressure is increased to 5 MPa with hydrogen. The mixture was heated to 200 ° C. while being pressurized and stirred, and then reacted for 4 hours to obtain a reaction solution containing 20% of a DCP / MTF / MTD ring-opening polymer hydrogenated polymer. After removing the hydrogenation catalyst by filtration, a soft polymer (manufactured by Kuraray; Septon 2002) and an antioxidant (manufactured by Ciba Specialty Chemicals; Irganox 1010) are added and dissolved in the resulting solutions. (Both 0.1 parts per 100 parts polymer). Next, cyclohexane and other volatile components, which are solvents, are removed from the solution using a cylindrical concentration dryer (manufactured by Hitachi, Ltd.), and the hydrogenated polymer is extruded in the form of a strand from the extruder in a molten state, and after cooling, pellets And recovered. When the copolymerization ratio of each norbornene monomer in the polymer was calculated from the composition of residual norbornenes in the solution after polymerization (by gas chromatography method), it was almost charged at DCP / MTF / MTD = 10/70/20. It was equal to the composition. This hydrogenated ring-opened polymer had a weight average molecular weight (Mw) of 31,000, a molecular weight distribution (Mw / Mn) of 2.5, a hydrogenation rate of 99.9%, and a Tg of 134 ° C.

  The obtained pellets of the ring-opened polymer hydrogenated product were dried at 70 ° C. for 2 hours using a hot air dryer in which air was circulated to remove moisture. Next, the pellets were subjected to a short shaft extruder having a coat hanger type T die having a lip width of 1.5 m (manufactured by Mitsubishi Heavy Industries, Ltd .: screw diameter 90 mm, T die lip material was tungsten carbide, peel strength from molten resin 44 N ) To produce a cycloolefin polymer film having a thickness of 80 μm and a slit width of 1.4 m. Extrusion molding was performed in a clean room of class 10,000 or less under molding conditions of a molten resin temperature of 240 ° C. and a T die temperature of 240 ° C. During the drying process, the obtained film was stretched 1.50 times in the width direction at a stretching temperature of 155 ° C. using a tenter device, and a cycloolefin polymer film having retardation values of Ro45 nm and Rt of 130 nm was obtained by the following measurement. It was. At that time, as a result of adjusting the length of the tenter device, the clip interval, and the tension of the clip, the orientation angle deviation between the in-plane slow axis of the film and the width direction of the film was within ± 0.4 °.

  The manufactured liquid crystal display device was evaluated for peripheral light leakage in the same manner as in Example 1. As a result, Example 1 was reproduced and the comparative liquid crystal display device 5 was evaluated as Δ. It was found that the liquid crystal display device 6 has a peripheral light leakage ◯, and the liquid crystal display devices 7 and 8 have a markedly improved peripheral light leakage.

Example 3
In preparation of the liquid crystal display device 4 of Example 1, Konica Minolta Tack KC8UXW-RHA (polarizing plate protective film with antireflection hard coat) was further bonded to the outermost surface of the front glass plate in the same manner. A liquid crystal display device 9 was produced.

  As a result of evaluation in the same manner as in Example 1, the liquid crystal display device 9 of the present invention showed no leakage of light, reduced glare and reflection due to surface reflection, and improved visibility.

Example 4
A rubbing treatment and an alignment film were formed using KC8UXW-H instead of the retardation film KC8UCR4 used in Example 1.

(Formation of alignment film)
A 1.5N potassium hydroxide solution (solvent: water / isopropyl alcohol / propylene glycol = 14/86/15 vol%) was applied to the surface of the prepared support 5 ml / m ² and held at 60 ° C. for 10 seconds. Thereafter, potassium hydroxide remaining on the surface of the support was washed with a dilute sulfuric acid solution for neutralization, washed with water, and dried.

On the support, a coating solution having the following composition was applied at 28 ml / m ² with a # 16 wire bar coater. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds.

  Next, the formed film was rubbed in a direction forming 45 ° with the longitudinal direction of the support. In this way, an alignment film was formed.

<Alignment film coating solution composition>
The following modified polyvinyl alcohol 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde (crosslinking agent) 0.5 parts by weight

(Formation of optically anisotropic layer with discotic liquid crystalline compound)
On the alignment film, 41.01 g of the following discotic liquid crystalline compound, ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 4.06 g, cellulose acetate butyrate (CAB551-0.2, Eastman Chemical Co., Ltd.) 0.90 g, cellulose acetate butyrate (CAB531-1, Eastman Chemical Co., Ltd.) 0.23 g, photopolymerization initiator (Irgacure 907, Ciba Geigy Co.) 1.35 g, sensitizer ( A coating solution prepared by dissolving 0.45 g of Kayacure DETX (manufactured by Nippon Kayaku Co., Ltd.) in 102 g of methyl ethyl ketone was applied with a wire bar of # 3.6. This was heated in a constant temperature zone of 130 ° C. for 2 minutes to align the discotic liquid crystalline compound. Next, UV irradiation was performed for 1 minute using a 120 W / cm high pressure mercury lamp in an atmosphere of 60 ° C. to polymerize the discotic liquid crystalline compound. Then, it stood to cool to room temperature.

  The retardation value of the retardation film on which the optically anisotropic layer was formed was Ro = 45 nm and Rt = 110 nm.

  In the production of the liquid crystal display device 4 of Example 1, the liquid crystal display device 10 of the present invention was produced using the retardation film having the optically anisotropic layer produced above.

  As a result of evaluation in the same manner as in Example 1, the liquid crystal display device 10 of the present invention was an excellent liquid crystal display device that reproduced the effects of the present invention and no light leakage was observed.

It is the schematic which shows a preferable example of the liquid crystal display device which concerns on this invention.

Explanation of symbols

A, B Polarizing plate 1 Polarizer 2 Polarizing plate protective film 3 Adhesive layer 4 Front plate 5 Retardation film 6 Liquid crystal cell 7 Fluid medium layer 8 Light diffusion plate 9 Backlight

Claims (10)

In a liquid crystal display device having at least one polarizing plate having a surface polarizing plate protective film, a polarizer, and a retardation film, and a liquid crystal cell, the polarizing film is disposed such that the retardation film side is the liquid crystal cell side, A liquid crystal display device, wherein a position fixing holding plate is attached to a surface protective film of a polarizing plate directly or via another layer, and the retardation film side is not attached to a liquid crystal cell. The liquid crystal display device according to claim 1, wherein the position fixing holding plate is a front plate or a light diffusion plate. The in-plane retardation value Ro of the support represented by the following formulas (i) and (ii) and the thickness direction retardation value Rt of the support satisfy the following ranges. 3. The liquid crystal display device according to 1 or 2.
20 (nm) ≦ Ro ≦ 300 (nm)
−100 (nm) ≦ Rt ≦ 400 (nm)
Formula (i) Ro = (nx−ny) × d
Formula (ii) Rt = {(nx + ny) / 2−nz} × d
(Where nx is the refractive index in the slow axis direction in the support surface, ny is the refractive index in the fast axis direction in the support surface, nz is the refractive index in the thickness direction of the support, and d Represents the thickness (nm) of the support.) The liquid crystal display device according to claim 1, wherein the retardation film is a cellulose ester film or a cyclic olefin-based resin film. The liquid crystal display device according to claim 1, further comprising a fluid medium layer between the retardation film and the liquid crystal cell. The liquid crystal display according to claim 1, wherein the position fixing holding plate is formed of at least one selected from a cyclic olefin resin, an acrylic resin, a polyester, and a glass plate. apparatus. The liquid crystal display device according to claim 1, wherein a surface of the position fixing holding plate is subjected to an antireflection process. The liquid crystal display device according to claim 1, wherein the liquid crystal cell is in a VA mode. The liquid crystal display device according to claim 1, wherein the retardation film further has an optically anisotropic layer. The liquid crystal display device according to claim 1, wherein the backlight is a direct type light emitting diode.

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