JP2007003766A - Optical film, manufacturing method of optical film, polarizing plate and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film which is manufactured by providing a functional thin film on a long film and which is of high uniformity having no occurrence of color irregularity and having no periodic unevenness of the color irregularities, no difference between a center and an edge part in an application width direction, no difference between the outside and the inside of a wound roll and no difference between lots, to provide a manufacturing method of the optical film and further to provide a polarizing plate and a liquid crystal display apparatus which use the optical film and are excellent in visibility. <P>SOLUTION: The manufacturing method of the optical film with the functional thin film provided on the long film, has a process of coating the long film with the functional thin film while the long film is continuously conveyed, and after coating, the optical film is wound up in a roll shape at ≥50°C and heating treatment is successively carried out at ≥50°C for one day or more. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical film, a method for producing an optical film, a polarizing plate, and a display device, and more particularly to an optical film having a functional thin film on the surface of a long film wound in a roll shape and a method for producing the same. Furthermore, the present invention relates to a polarizing plate and a display device using the optical film.

  In addition to the CRT, various display devices such as a liquid crystal television, a plasma display (PDP), and an organic EL display have been developed, and their screen sizes are increasing. With an increase in screen size and image quality, an optical film on which an antireflection layer or the like is formed is attached to the front surface of a display device in order to improve visibility. In addition, such a large-screen display device is easily scratched because it may be directly touched by hands or touched by objects. Therefore, an antireflection film with a hard coat layer in which a hard coat layer is usually formed on a support for preventing scratches and an antireflection layer or the like is formed thereon has been used.

  As the antireflection film, a wide film having a size of 1 m or more, and further 1.4 m or more is particularly required due to an increase in screen size. However, when the width is increased due to the increase in size as described above, the reflectance and the color of the reflected light are often uneven, and periodic unevenness often occurs. There is a need for a highly uniform optical film that does not have a difference between the outside and inside of the winding, the difference between the center and the end in the width direction, and the difference between lots.

  Conventionally, when handling long rolls of plastic film, it is possible to tighten the roll wound around the core or to store it at the time of storage by providing portions that are bulkier than the film surface called knurling or embossing on both sides of the film. A method for preventing folding or the like from occurring is known (see, for example, Patent Documents 1 and 2).

  On the other hand, various optical films having various functional thin films on long-rolled plastic films are known. After forming a functional thin film on the base material, the film is constant for improving the strength of the thin film or in a short time. It is known to perform a heat treatment called curing or aging in order to obtain a high strength (see, for example, Patent Documents 3 and 4). It is described that an optical film having a high surface hardness can be obtained by heat treatment at 40 to 150 ° C. for 30 minutes to several weeks in a wound state.

However, in these conventional techniques, there is no description that an optical film with high uniformity without color unevenness can be obtained by applying these techniques to the production of a wide optical film, There has been a strong desire to provide a method for producing an optical film with high uniformity because the difference between lots and the difference between roll unwinding and winding are small. In particular, it has been found that the difference between the inside and the outside of the winding increases as the optical film becomes thinner.
Japanese Patent Laid-Open No. 2002- 211803 Japanese Patent No. 3226190 JP 2001-91705 A JP 2002-6104 A

  The purpose of the present invention is to produce an optical film in which a functional thin film is provided on a long film, the occurrence of color unevenness and periodic unevenness of the color unevenness, the difference between the center and the end in the width direction of application, An object of the present invention is to provide a highly uniform optical film and a method for producing the same without causing a difference between unwinding and winding of a roll and a difference between lots. Furthermore, it is providing the polarizing plate and display apparatus which were excellent in the visibility using this optical film.

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

(Claim 1)
In the manufacturing method of the optical film which provides a functional thin film on a long film, it has the process of conveying a long film continuously and coating a functional thin film, and after coating, this optical film is temperature 50 degreeC or more. A method for producing an optical film, which is wound up in a roll and subsequently subjected to heat treatment at 50 ° C. or more for 1 day or more.

(Claim 2)
The method for producing an optical film according to claim 1, wherein the functional thin film is an antireflection layer.

(Claim 3)
When winding up the optical film in a roll shape, the atmospheric temperature of the winding chamber is 50 to 150 ° C, or winding is performed while applying hot air of 50 ° C or higher to the winding roll. The manufacturing method of the optical film of 1 or 2.

(Claim 4)
It has a step of coating a functional thin film by continuously transporting a long film. After coating, the optical film is wound up in a roll and subjected to heat treatment at 50 ° C. or more for 1 day or more. A method for producing an optical film, wherein the film is cooled while rewinding after completion of the treatment.

(Claim 5)
5. The method for producing an optical film according to claim 4, wherein the optical film after completion of the heat treatment is passed through an atmosphere having a relative humidity of 10 to 70% RH while being wound, or is wound up in the atmosphere.

(Claim 6)
An optical film manufactured by the method for manufacturing an optical film according to claim 1.

(Claim 7)
The optical film according to claim 6, wherein the optical film has a low refractive index layer containing hollow fine particles.

(Claim 8)
A polarizing plate using the optical film according to claim 6 or 7 on at least one surface.

(Claim 9)
A display device comprising the polarizing plate according to claim 8.

  According to the present invention, in an optical film manufacturing method in which a functional thin film is provided on a long film, the occurrence of color unevenness, the periodic unevenness of the color unevenness, the difference between the center and the end in the width direction of the coating, It is possible to provide a highly uniform optical film and a method for producing the same without causing a difference between unwinding and winding and a difference between lots. Furthermore, a polarizing plate and a display device having excellent visibility using the optical film can be provided.

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

  The optical film according to the present invention has a functional thin film on a long film. As the functional thin film, antireflection, antiglare, infrared absorption, ultraviolet absorption, antistatic, electromagnetic wave shielding, scratch resistance, etc. It is a thin film having functions such as improvement, antifouling property improvement, retardation for optical compensation, and visual field enlargement. In particular, the optical film according to the present invention is used by being affixed to the surface of a large display device, and is preferably a functional thin film mainly intended for improving scratch resistance and preventing reflection.

  In the method for producing an optical film in which a functional thin film is provided on the long film, the inventors have a step of continuously conveying the long film to coat the functional thin film, and after coating, the optical film The film is wound into a roll at a temperature of 50 ° C. or higher, and subsequently subjected to a heat treatment at 50 ° C. or higher for 1 day or longer (also referred to as aging or aging treatment in the present invention), thereby generating color unevenness and the period of the color unevenness. It has been found that a highly uniform optical film can be produced without unevenness of shape, difference between center and end in the width direction of coating, difference between roll unwinding and winding, difference between lots, etc. It is up to that.

  Furthermore, when winding the optical film in a roll shape, it is preferable that the winding chamber has an atmospheric temperature of 50 to 150 ° C. or is wound while applying hot air of 50 ° C. or more to the winding roll. In the state where the optical film is wound up in a roll shape, the heat treatment is performed at 50 ° C. or more for 1 day or more. Further, cooling is performed while rewinding after completion of the heat treatment, and at that time, the optical film after the heat treatment is rewinded and passed through an atmosphere having a relative humidity of 10 to 70% RH or wound in the atmosphere. Are also found to be preferable.

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

(Coating, heat treatment and rewinding)
The functional thin film coating, drying, subsequent heat treatment and rewinding steps of the present invention will be described with reference to the drawings. The figure shows a preferred example of the present invention and is not limited to this.

  FIG. 1 is a schematic view showing a coating and drying process according to the present invention followed by a heating process and a rewinding process.

  The long film Y is unwound from the unwinding roll 1, is transported by the transport roller 2, and is coated with a functional thin film by the extrusion coater 3. At this time, the functional thin film may have a single layer structure or a plurality of layers. The long film Y coated with the functional thin film is then dried by the first drying zone 5. Drying is performed by blowing warm air whose temperature and humidity are controlled from the front surface, back surface, or both surfaces of the long film Y. After drying, if necessary, the actinic ray lamp 6a in the actinic ray irradiation unit 6 is irradiated with actinic rays such as ultraviolet rays to cure the thin film. Alternatively, the half-cure state can be achieved by controlling the irradiation amount and irradiation conditions. Actinic ray irradiation can also be performed in a state where the long film Y is wound around the opposing roll 4 whose temperature is controlled to 20 to 120 ° C. in advance. After irradiation with actinic rays, if necessary, further heat treatment can be performed in the second drying zone. The functional thin film can be further cured by the second drying zone 7 in which a plurality of transport rollers 2 are installed. In order to cure the surface of the uniform functional thin film, the drying temperature is preferably in the range of 50 to 150 ° C. in both the first and second drying zones.

  The present invention is characterized in that an optical film coated with a functional thin film is wound up in a roll shape at a temperature of 50 ° C. or higher, and subsequently heat-treated at 50 ° C. or higher for one day or longer.

  The present inventors analyzed the occurrence of wrinkles and slippage at the time of winding, performing the temperature at the time of film winding at a relatively high temperature, and the wrinkles of the roll wound by subsequent heat treatment, Not only can the occurrence of slippage be suppressed, but also color unevenness of the functional thin film, periodic unevenness, difference between the center and end in the width direction, difference between roll unwinding and winding, difference between lots, etc. As a result, the present inventors have found that an optical film with high uniformity without any problem can be obtained, and have achieved the present invention.

  In this invention, it is preferable to wind up, setting the atmospheric temperature of a winding chamber to the range of 50-150 degreeC, or applying 50 degreeC or more warm air to a winding roll.

  In order to adjust the atmospheric temperature of the winding chamber to 50 to 150 ° C., warm air may be introduced into the winding chamber with an appropriate heat source to adjust the temperature of the entire room. Alternatively, the temperature around the winding portion can be set to that temperature. Or it is also preferable to provide a heating process before a winding process, and to wind up before a film temperature is cooled to less than 50 degreeC. As a measure for preventing electrification and dust adhesion, it is preferable to adjust the warm air to a relative humidity in the range of 10 to 70% RH, preferably 20 to 70% RH, particularly 40 to 60% RH. Moreover, it is preferable that warm air is an ion wind, and it is preferable to install a static elimination apparatus and an air cleaner in the vicinity of the winding part.

  Further, a method of winding while applying hot air of 50 ° C. or higher to the winding roll is preferable because the temperature of the film itself and the winding core can be easily matched. When the temperature of the winding core and the film are different, wrinkles are generated on the core and a film with a good winding shape is often not obtained. However, this method can be improved. Moreover, it is advantageous in terms of cost compared with a method of adjusting the temperature of the entire winding chamber.

  The winding speed is preferably 10 to 80 m / min.

  Although FIG. 1 shows an example in which warm air is blown from the hot air blowing port 10 to the take-up roll 9, one hot air blowing port 10 may be provided, but by providing a plurality of hot air blowing ports 10 to the film and the winding core. This is preferable because the temperature can be adjusted accurately in a short time. Moreover, it is a preferable method also at the point which can limit the zone heated.

  The winding core may be of any material, but is preferably a hollow plastic core, and the plastic material may be any heat-resistant plastic that can withstand the heat treatment temperature, For example, resins such as a phenol resin, a xylene resin, a melamine resin, a polyester resin, and an epoxy resin can be given. A thermosetting resin reinforced with a filler such as glass fiber is preferable.

  The winding number of these winding cores is preferably 100 turns or more, more preferably 500 turns or more, the winding thickness is preferably 5 to 200 cm, and the film width is 1 to 4 m. It is preferable that it is 1.4 to 2 m.

  In the case of a method in which hot air is directly blown onto the winding core and its peripheral portion, it is preferable to prevent heat transfer to the core chuck portion so that distortion due to thermal expansion does not occur in the core chuck portion having a complicated structure.

  FIG. 2 is a schematic view of a winding core portion preferable for the present invention.

  The take-up core 15 is supported by a core support shaft 16 and a core chuck 17. As a means for preventing heat transfer to the core chuck, the core chuck is made of ceramic, the core chuck structure is made of ceramic at the tip, and heat retaining water (cooling water) is flowed to the support side to prevent heat transfer. It is preferable to take The heating zone 19 is preferably limited to the periphery of the take-up core 15 as much as possible by adjusting the angle, attachment position, and number of attachments of the hot air outlet 10.

  Also, a method of preheating the core before setting it on the core chuck, setting it to a desired temperature, and then setting it on the take-up shaft is preferable in terms of reducing the hot air blowing load.

  The temperature of the hot air is preferably 50 ° C. or higher, but is preferably Tg or lower of the optical film. When winding at Tg or higher, the optical film needs to be wound at a tension that does not stretch in order to maintain a certain flatness, and the winding shaft is set so that the speed before the heating zone and the winding peripheral speed are the same. It is necessary to make adjustments and press the roll against the surface of the film being wound. From such a viewpoint, the temperature of the warm air is preferably 50 to 150 ° C.

  The wound optical film roll is then subjected to heat treatment at 50 ° C. or higher for 1 day or longer, thereby generating color unevenness, periodic unevenness of the color unevenness, center and end portions in the width direction of application. It is possible to obtain an optical film with high uniformity without any difference in roll, difference between roll unwinding and winding, and difference between lots.

  In the heat treatment according to the present invention, the optical film roll wound around the movable carriage 12 is moved, and the heat treatment is performed at the required temperature and the required number of days in the heating zones indicated by A to F in FIG. The Each heating zone is preferably a clean room free of dust. In this invention, it is necessary to heat-process at 50 degreeC or more for 1 day or more, and preferable temperature is 50-150 degreeC, More preferably, it is 60 degreeC-120 degreeC, Most preferably, it is 70 degreeC-110 degreeC. The temperature to be held is preferably in the range of ± 5 ° C. of the set temperature. Each of the heating zones indicated by A to F is preferably designed so that the temperature can be changed. A sudden temperature rise increases the temperature difference between the inside and outside of the optical film roll. For example, it is preferable to increase the temperature in the heating zones A to C with a temperature difference of about 20 ° C. to 30 ° C. On the contrary, it is preferable to gradually lower the temperature in the second half portions D to F of the heating zone.

  The number of days for the heat treatment is preferably 3 days or more, and more preferably about 3 to 30 days from the viewpoint of productivity and cost. In particular, the predetermined temperature (temperature constant portion) is preferably 3 days or more.

  The heat-treated optical film is cooled and sent to the next step.

  The optical film roll after the heat treatment is installed in the zone G of the rewinding step 13 and is preferably cooled to room temperature while rewinding the optical film to obtain the rewind roll 14. Further, in the present invention, it is preferable to pass an atmosphere having a relative humidity of 10 to 70% RH between the zones H to J of the rewinding process while winding the optical film, or to wind in the atmosphere. When the relative humidity is preferably 20 to 70% RH, particularly 40 to 60% RH, a good optical film roll can be obtained without static electricity failure or collapse of the winding shape.

  The film rewinding speed is 1 to 200 m / min, preferably 10 to 100 m / min. At the time of rewinding, it is preferable that the film is drawn out and brought into contact with at least one roller in order to lower the film temperature.

  When rotating or rewinding these rolls, there is a possibility that static electricity failure or scratches may occur on the film. It is preferable to install a static eliminator or in a clean room. The surface of the contact roller during rewinding is smooth. It is preferable to use one having a high value.

(Long film)
Next, the long film that can be used in the present invention will be described.

  As a long film according to the present invention, it is preferable that it is easy to manufacture, has good adhesion with a functional thin film, is optically isotropic, and is optically transparent. It is done.

  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.

  Although it will not specifically limit if it has said property, For example, polyester films, such as polyester film, polycarbonate film, polyarylate film, polysulfone (including polyethersulfone) film, polyethylene terephthalate, polyethylene naphthalate Film, polyethylene film, polypropylene film, cellophane, cellulose diacetate film, cellulose triacetate film, cellulose acetate butyrate film, cellulose acetate film such as cellulose acetate propionate film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol Film, syndiotactic polystyrene film, polycarbonate film, shiku Olefin polymer film (Arton (manufactured by JSR), ZEONEX, ZEONOR (manufactured by ZEON CORPORATION)), polymethylpentene film, polyetherketone film, polyetherketoneimide film, polyamide film, fluororesin film, nylon film, A polymethyl methacrylate film, an acrylic film, a glass plate, etc. can be mentioned. Among them, a cellulose ester film, a polycarbonate film, and a polysulfone (including polyether sulfone) are preferable, and in the present invention, a cellulose ester film (for example, Konica Minoltack product names KC8UX2MW, KC4UX2MW, KC8UY, KC4UY, KC5UN, KC12UR, KC8UCR3, KC8UCR4, KC8UCR5, KC8UX-H (manufactured by Konica Minolta Co., Ltd.) are preferably used from the viewpoints of production, cost, transparency, isotropic properties, adhesiveness, and the like. These films may be films produced by melt casting film formation or films produced by solution casting film formation.

Retardation R _t in the thickness direction as the optical properties of the long film is -300Nm～300nm, retardation R ₀ in the plane direction those 0nm~1000nm is preferably used.

  In the present invention, it is preferable to use a cellulose ester film as the long film. As the cellulose ester, cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate are preferable. Among them, cellulose acetate butyrate, cellulose acetate phthalate, and cellulose acetate propionate are preferably used.

  In particular, a film having a mixed fatty acid ester of cellulose in which X and Y are in the following ranges when the substitution degree of the acetyl group is X and the substitution degree of the propionyl group or butyryl group is Y 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 long film according to the present invention, cellulose as a raw material for 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. 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. Moreover, the cellulose ester film which has a C4 or more acyl group or carbamoyl group may be sufficient.

  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 a high mechanical strength when molded and an appropriate dope viscosity, and more preferably 80000 to 150,000.

  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 the preparation of these dopes is preferably capable of dissolving the 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. More preferably, biaxial stretching is performed in the width direction and the longitudinal direction, and when the residual solvent is 3% by mass to 40% by mass, the width direction and the longitudinal direction are 1.01 times to 1.5 times, respectively. It is desirable to be stretched. By doing in this way, the film excellent in planarity and dimensional stability can be obtained.

  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.

  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 support 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 conforms to JIS Z 0208 (25 ° C., 90% RH). The measured 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 10 to 160 g / m ² · 24 hours or less. It is. In particular, it is preferable that the film thickness is 10 μm to 80 μm and the moisture permeability is within the above range.

  The long film of the present invention specifically has a length of about 100 m to 5000 m, and is usually in the form of a roll. The width of the long film used for the optical film of the present invention is preferably 1 m or more, more preferably 1.4 m or more, and particularly preferably 1.4 to 4 m.

  When a cellulose ester film is used for the long film of the present invention, it is preferable to contain the following plasticizer from the viewpoints of flexibility, moisture permeability, and dimensional stability. Examples of plasticizers include phosphate ester plasticizers, phthalate ester plasticizers, trimellitic acid ester plasticizers, pyromellitic acid plasticizers, glycolate plasticizers, and citrate ester plasticizers. Alcohol ester plasticizers, polyester plasticizers, and the like can be preferably used.

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

  In the present invention, the polyhydric alcohol ester plasticizer refers to a compound obtained by condensing a compound having a plurality of hydroxyl groups in one molecule and a plurality of monovalent organic acids as a polyhydric alcohol ester plasticizer. .

  Examples of preferred polyhydric alcohols include the following, but the present invention is not limited to these. Adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3- Butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,2,4-trimethylpentane- 1,3-diol, 1,6-hexanediol, 1,2,3-hexanetriol, 1,2,6-hexanetriol, glycerin, diglycerin, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, gas Kuchitoru, glucose, cellobiose, inositol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, and xylitol. In particular, diethylene glycol, triethylene glycol, glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol are preferable.

  Examples of preferable organic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, pivalic acid, acrylic acid, methacrylic acid, cyclohexanecarboxylic acid, benzoic acid, naphthoic acid, and the like. It is preferable that the polyhydric alcohol ester is formed of an unsaturated carboxylic acid having a high effect of reducing.

  The unsaturated carboxylic acid used in the polyhydric alcohol ester may be one type or a mixture of two or more types. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.

  Among specific examples of such polyhydric alcohol ester plasticizers, for example, ethylene glycol plasticizers include ethylene glycol alkyl ester plasticizers such as ethylene glycol diacetate and ethylene glycol dibutyrate, and ethylene glycol dibutylate. Examples thereof include ethylene glycol cycloalkyl ester plasticizers such as cyclopropylcarboxylate and ethylene glycol dicyclohexylcarboxylate, ethylene glycol dibenzoate, and ethylene glycol di4-methylbenzoate.

  Specific examples of glycerin ester plasticizers include glycerin alkyl esters such as triacetin, tributyrin, glycerin diacetate caprylate, glycerin oleate propionate, and glycerin cycloesters such as glycerin tricyclopropyl carboxylate and glycerin tricyclohexyl carboxylate. Diglycerol alkyl esters such as alkyl esters, glycerol aryl esters such as glycerol tribenzoate, glycerol 4-methylbenzoate, diglycerol tetraacetylate, diglycerol tetrapropionate, diglycerol acetate tricaprylate, diglycerol tetralaurate , Diglycerin tetracyclobutylcarboxylate, diglycerin tetracyclopentylcarboxylate, etc. Diglycerol cycloalkyl esters, diglycerin tetrabenzoate, diglycerin 3-methylbenzoate or the like.

  Specific examples of polyhydric alcohol ester plasticizers other than those described above include the compounds described in paragraph Nos. [30 to 33] of JP-A No. 2003-12823, or the chemical formulas 2 to 12 of Japanese Patent Application No. 2004-356546. Compounds.

  The plasticizer listed above may be further substituted with an alkyl group, an alkoxy group, an acyl group, an oxycarbonyl group, a carbonyloxy group or the like in both the polyhydric alcohol part or the organic acid part. They may be bonded by a covalent bond. Alternatively, these structures may be part of the polymer, or may be regularly pendant, and are introduced into part of the molecular structure of additives such as antioxidants, acid scavengers, and UV absorbers. May be.

  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.

  An ultraviolet absorber is preferably used for the long film of the present invention.

  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 ultraviolet absorbers preferably used in the present invention include, for example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine 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 commercially available polymer ultraviolet absorber, PUVA-30M (manufactured by Otsuka Chemical Co., Ltd.) can be preferably used.

  In the present invention, it is preferable to contain a fine matting agent in order to impart slipperiness to the long cellulose ester film. Examples of the fine matting agent include silicon dioxide, titanium dioxide, aluminum oxide, and zirconium oxide. It is preferable to contain inorganic fine particles such as calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, and crosslinked polymer fine particles. Of these, silicon dioxide is preferable because it can reduce the haze of the film.

  The primary average particle diameter of the fine particles added to the long 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 long 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 the particles with a transmission electron microscope (magnification 500,000 to 2,000,000 times), observing 100 particles, measuring the particle diameter, and measuring the average. The value was taken as the primary average particle size.

  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.

  Silicon dioxide 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 equation by taking a certain amount of silicon dioxide fine particles in a graduated cylinder, measuring the weight at this time.

Apparent specific gravity (g / liter) = silicon dioxide mass (g) / volume of silicon dioxide (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 fine particle dispersibility, and preparation method C is excellent in that the fine particles are difficult to reaggregate. Among them, the preparation method B described above is a preferable preparation method that is excellent in both dispersibility of the fine particles and difficulty in reaggregating the fine particles.

《Distribution method》
The concentration of the fine particles when the fine particles are mixed with a solvent and dispersed is preferably 5% by mass to 30% by mass, more preferably 10% by mass to 25% by mass, and most preferably 15% by mass 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 amount of the fine particles added to the cellulose ester is preferably 0.01 parts by mass to 5.0 parts by mass, more preferably 0.05 parts by mass to 1.0 part by mass with respect to 100 parts by mass of the cellulose ester. 1 part by mass to 0.5 part by mass is 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 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 dispersion apparatus include an ultra-high pressure homogenizer (trade name: Microfluidizer) manufactured by Microfluidics Corporation or a nanomizer manufactured by Nanomizer, and a Manton Gorin type high-pressure dispersion apparatus such as a 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.

  The functional thin film which concerns on this invention is provided using the elongate film obtained in this way. Until processing or shipment, packaging is usually performed in order to protect the product from dirt, static electricity, and the like. The packaging material is not particularly limited as long as the above purpose can be achieved. Specific examples include polyethylene, polyester, polypropylene, nylon, polystyrene, paper, various non-woven fabrics, and the like. Those in which the fibers are mesh cloth are more preferably used.

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

  For example, a sequential multilayer casting method in which two or three layers are configured through different dies, a simultaneous multilayer casting method in which two or three slits are merged in a die having two or three slits, and a sequential multilayer casting Any of the multi-layer casting methods combining the simultaneous multi-layer casting with the rolling 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.

The number of bright spots of 0.005 mm to 0.01 mm is preferably 200 / cm ² or less, more preferably 100 / cm ² or less, 50 / cm ² or less, 30 / 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 thing with few also about a bright spot 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.

《Hard coat layer》
In the present invention, it is preferable that a hard coat layer is provided as a functional thin film on a long film.

  The hard coat layer used in the present invention is provided on at least one surface of the long film. The optical film of the present invention preferably comprises an antireflection film in which an antireflection layer (high refractive index layer, low refractive index layer, etc.) is provided on the hard coat layer.

  As the hard coat layer, an actinic radiation curable resin layer is preferably used.

  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 derivatives thereof, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and the like. 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.

  Commercially available UV 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.); Seica 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 (Sanyo Chemical Industries, Ltd.); 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. These light sources are preferably air-cooled or water-cooled. 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 .

  Further, it is preferable to reduce the oxygen concentration to 0.01% to 2% by nitrogen purge in the irradiated portion.

  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, it is 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.

  More preferably, when the film thickness of the long film is 10 to 80 μm and the ratio (d / H) of the film thickness (H) of the layer to the film thickness (d) of the long film is 4 to 10, It has excellent hardness and scratch resistance. This is because the hardness and scratch resistance are inferior when the hard coat layer is thinner than the film thickness of the long film, and the flatness is deteriorated when the hard coat layer is thicker than the film thickness of the long film.

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.

  It is preferable to add fine particles to the hard coat layer used in the present invention, and as the inorganic fine particles used, silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide, calcium carbonate, calcium carbonate, talc, clay, Examples include calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. In particular, silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide and the like are preferably used.

  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.

The hard coat layer used in the present invention preferably contains an antistatic agent. Examples of the antistatic agent include Sn, Ti, In, Al, Zn, Si, Mg, Ba, Mo, W and A conductive material containing at least one element selected from the group consisting of V as a main component and having a volume resistivity of 10 ⁷ Ω · cm or less is preferable.

  Examples of the antistatic agent include metal oxides and composite oxides having the above elements.

Examples of metal oxides include, for example, ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, MoO ₂ , V ₂ O ₅ , or complex oxides thereof. ZnO, In ₂ O ₃ , TiO ₂ and SnO ₂ are particularly preferable. Examples of containing different atoms include, for example, addition of Al and In to ZnO, addition of Nb and Ta to TiO ₂ , and addition of Sb, Nb and halogen elements to SnO ₂ . Addition is effective. The amount of these different atoms added is preferably in the range of 0.01 to 25 mol%, particularly preferably in the range of 0.1 to 15 mol%. In addition, the volume resistivity of these metal oxide powders having conductivity is 10 ⁷ Ω · cm or less, particularly 10 ⁵ Ω · cm or less.

<Antireflection layer>
In the optical film of the present invention, it is preferable to further provide an antireflection layer as a functional thin film on the hard coat layer. In particular, a low refractive index layer containing hollow fine particles is preferable.

(Low refractive index layer)
The low refractive index layer used in the present invention preferably contains hollow fine particles, and more preferably contains a silicon alkoxide, a silane coupling agent, a curing agent and the like.

<Hollow particles>
The low refractive index layer preferably contains the following hollow fine particles.

  The hollow fine particles referred to here are (1) composite particles composed of porous particles and a coating layer provided on the surface of the porous particles, or (2) hollow inside, and the content is a solvent, gas or Cavity particles filled with a porous material. In addition, the coating liquid for low refractive index layers should just contain either (1) composite particle | grains or (2) cavity particle | grains, and 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 size of such inorganic fine particles is in the range of 5 to 300 nm, preferably 10 to 200 nm. The inorganic fine particles used are appropriately selected according to the thickness of the transparent film to be formed, and may be in the range of 2/3 to 1/10 of the film thickness of the formed transparent film such as a low refractive index layer. desirable. These inorganic fine particles are preferably used in a state of being dispersed in an appropriate medium in order to form a low refractive index layer. As the dispersion medium, water, alcohol (for example, methanol, ethanol, isopropyl alcohol), ketone (for example, methyl ethyl ketone, methyl isobutyl ketone), and ketone alcohol (for example, diacetone alcohol) are preferable.

  The thickness of the coating layer of the composite particles or the thickness of the particle walls of the hollow particles is desirably in the range of 1 to 20 nm, preferably 2 to 15 nm. In the case of composite particles, when the thickness of the coating layer is less than 1 nm, the particles may not be completely covered, and the low refractive index effect may not be sufficiently obtained. On the other hand, when the thickness of the coating layer exceeds 20 nm, the porosity (pore volume) of the composite particles may be lowered, and the low refractive index effect may not be sufficiently obtained. In the case of hollow particles, when the particle wall thickness is less than 1 nm, the particle shape may not be maintained, and even if the thickness exceeds 20 nm, the effect of low refractive index may not be sufficiently exhibited. is there.

The coating layer of the composite particles or the particle wall of the hollow particles preferably contains silica as a main component. The coating layer of the composite particle or the particle wall of the hollow particle may contain a component other than silica, specifically, Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO _2. and _{CeO 2, P 2 O 3,} Sb 2 O 3, MoO 3, ZnO 2, WO 3 and the like. Examples of the porous particles constituting the composite particles include those made of silica, those made of silica and an inorganic compound other than silica, and those made of CaF ₂ , NaF, NaAlF ₆ , MgF, and the like. Among these, porous particles made of a composite oxide of silica and an inorganic compound other than silica are particularly preferable. Examples of inorganic compounds other than silica include Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , P ₂ O ₃ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ , WO _{3 and the} like. 1 type or 2 types or more can be mentioned. In such porous particles, the molar ratio MOX / SiO ₂ when the silica is represented by SiO ₂ and the inorganic compound other than silica is represented by oxide (MOX) is 0.0001 to 1.0, preferably It is desirable to be in the range of 0.001 to 0.3. It is difficult to obtain a porous particle having a molar ratio MOX / SiO ₂ of less than 0.0001, and even if it is obtained, conductivity is not exhibited. On the other hand, if the molar ratio MOX / SiO _{2 of} the porous particles exceeds 1.0, the ratio of silica decreases, so that particles having a small pore volume and a low refractive index may not be obtained.

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

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

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

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

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

  Moreover, the alkali-soluble conductive compound is used as a raw material for inorganic compounds other than silica.

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

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

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

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

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

  In addition, prior to removing inorganic compounds other than silica from the porous particle precursor, a silicic acid solution obtained by removing the alkali metal salt of silica from the porous particle precursor dispersion obtained in the first step. Alternatively, it is preferable to form a silica protective film by adding a hydrolyzable organosilicon compound. The thickness of the silica protective film may be 0.5 to 15 nm. Even if the silica protective film is formed, the protective film in this step is porous and thin, so that it is possible to remove inorganic compounds other than silica described above from the porous particle precursor.

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

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

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

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

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

Third step: Formation of silica coating layer In the third step, a hydrolyzable organosilicon compound or silicic acid solution is added to the porous particle dispersion prepared in the second step (in the case of hollow particles, a hollow particle precursor dispersion). Is added to coat the surface of the particles with a polymer such as a hydrolyzable organosilicon compound or a silicic acid solution to form a silica coating layer.

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

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

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

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

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

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

  The refractive index of the inorganic fine particles thus obtained is as low as less than 1.44. Such inorganic fine particles are presumed to have a low refractive index because the porosity inside the porous particles is maintained or the inside is hollow.

The low refractive index layer used in the present invention preferably contains a hydrolyzate of an alkoxysilicon compound and a condensate formed by a subsequent condensation reaction in addition to the hollow fine particles. In particular, it is preferable to contain a SiO ₂ sol prepared by adjusting an alkoxysilicon compound represented by the following general formula (1) and / or (2) or a hydrolyzate thereof.

General formula (1) R1-Si (OR2) ₃
General formula (2) Si (OR2) ₄
(In the formula, R1 represents a methyl group, an ethyl group, a vinyl group, or an organic group containing an acryloyl group, a methacryloyl group, an amino group or an epoxy group, and R2 represents a methyl group or an ethyl group)
Hydrolysis of the silicon alkoxide and silane coupling agent is performed by dissolving the silicon alkoxide and silane coupling agent in a suitable solvent. Examples of the solvent to be used include ketones such as methyl ethyl ketone, alcohols such as methanol, ethanol and isopropyl alcohol butanol, esters such as ethyl acetate, and mixtures thereof.

  To the solution obtained by dissolving the silicon alkoxide or the silane coupling agent in a solvent, an amount of water slightly larger than that required for hydrolysis is added, and the temperature is 15 to 35 ° C., preferably 20 to 30 ° C. for 1 to 48 hours. The stirring is preferably performed for 3 to 36 hours.

  In the hydrolysis, a catalyst is preferably used. As such a catalyst, an acid such as hydrochloric acid, nitric acid, sulfuric acid or acetic acid is preferably used. These acids are used in an aqueous solution of about 0.001N to 20.0N, preferably about 0.005 to 5.0N. The water in the catalyst aqueous solution can be water for hydrolysis.

  The alkoxy silicon compound is hydrolyzed for a predetermined time, the prepared alkoxy silicon hydrolyzed solution is diluted with a solvent, and other necessary additives are mixed to prepare a coating solution for a low refractive index layer. The low refractive index layer can be formed on the base material by applying and drying on a base material such as a film.

<Alkoxy silicon compound>
In the present invention, the alkoxysilicon compound (hereinafter also referred to as alkoxysilane) used for the preparation of the low refractive index layer coating solution is preferably represented by the following general formula (3).

General formula (3) R4-nSi (OR ') n
In the general formula, R ′ represents an alkyl group, R represents a hydrogen atom or a monovalent substituent, and n represents 3 or 4.

  Examples of the alkyl group represented by R ′ include groups such as a methyl group, an ethyl group, a propyl group, and a butyl group, which may have a substituent, and the substituent exhibits properties as an alkoxysilane. If it is, there is no restriction | limiting in particular, For example, although you may substitute by halogen atoms, such as a fluorine, an alkoxy group, etc., More preferably, it is an unsubstituted alkyl group, and especially a methyl group and an ethyl group are preferable.

  The monovalent substituent represented by R is not particularly limited, and examples thereof include an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aromatic heterocyclic group, and a silyl group. Of these, an alkyl group, a cycloalkyl group, and an alkenyl group are preferable. These may be further substituted. Examples of the substituent for R include a halogen atom such as a fluorine atom and a chlorine atom, an amino group, an epoxy group, a mercapto group, a hydroxyl group, and an acetoxy group.

Specific preferred examples of the alkoxysilane represented by the general formula include tetramethoxysilane, tetraethoxysilane (TEOS), tetra n-propoxy silane, tetraisopropoxy silane, tetra n-butoxy silane, tetra t- Butoxysilane, tetrakis (methoxyethoxy) silane, tetrakis (methoxypropoxy) silane,
Further, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-butyltrimethoxysilane, i-butyltrimethoxysilane, n-hexyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3 -Mercaptopropyltrimethoxysilane, acetoxytriethoxysilane, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) trimethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, (3, 3, - trifluoropropyl) trimethoxysilane, pentafluorophenyl phenylpropyl trimethoxysilane, further, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane and the like.

  Alternatively, quantified silicon compounds such as silicate 40, silicate 45, silicate 48, and M silicate 51 manufactured by Tama Chemical, in which these compounds are partially condensed may be used.

  Since the alkoxysilane has a silicon alkoxide group that can be hydrolyzed and polycondensed, these alkoxysilanes are crosslinked by hydrolysis and condensation to form a network structure of the polymer compound. A layer containing uniform silicon oxide is formed on the base material by applying it on the base material and drying it as a refractive index layer coating solution.

  The hydrolysis reaction can be carried out by a known method and dissolved in the presence of a predetermined amount of water and a hydrophilic organic solvent such as methanol, ethanol or acetonitrile so that the hydrophobic alkoxysilane and water can be easily mixed. -After mixing, a hydrolysis catalyst is added to hydrolyze and condense the alkoxysilane. Usually, by carrying out hydrolysis and condensation reaction at 10 ° C. to 100 ° C., a liquid silicate oligomer having two or more hydroxyl groups is generated, and a hydrolyzed solution is formed. The degree of hydrolysis can be appropriately adjusted depending on the amount of water used.

  In the present invention, as a solvent to be added to alkoxysilane together with water, methanol and ethanol are preferable because they are inexpensive and the properties of the resulting film are excellent and the hardness is good. Although isopropanol, n-butanol, isobutanol, octanol, and the like can be used, the hardness of the obtained film tends to be low. The amount of the solvent is 50 to 400 parts by mass, preferably 100 to 250 parts by mass with respect to 100 parts by mass of the tetraalkoxysilane before hydrolysis.

  In this way, a hydrolyzed solution is prepared, diluted with a solvent, and if necessary, an additive is added and mixed with components necessary to form a low refractive index layer coating solution. A coating solution is used.

<Hydrolysis catalyst>
Examples of the hydrolysis catalyst include acids, alkalis, organic metals, metal alkoxides, etc. In the present invention, inorganic acids or organic acids such as sulfuric acid, hydrochloric acid, nitric acid, hypochlorous acid, and boric acid are preferable. In particular, carboxylic acids such as nitric acid and acetic acid, polyacrylic acid, benzenesulfonic acid, paratoluenesulfonic acid, methylsulfonic acid and the like are preferable, and among these, nitric acid, acetic acid, citric acid, tartaric acid and the like are preferably used. 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, pyruvic 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 also preferably used.

  Of these, those which volatilize the acid during drying and do not remain in the film are preferred, and those having a low boiling point are preferred. Therefore, acetic acid and nitric acid are particularly preferable.

  The added amount is 0.001 to 10 parts by mass, preferably 0.005 to 5 parts by mass with respect to 100 parts by mass of the alkoxysilicon compound (for example, tetraalkoxysilane) to be used. 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.

  When the alkoxysilane is hydrolyzed, the following inorganic fine particles are preferably mixed.

  The hydrolysis solution is allowed to stand for a predetermined time after the start of hydrolysis, and used after the progress of hydrolysis reaches a predetermined level. The standing time is a time during which the above-described crosslinking by hydrolysis and condensation proceeds sufficiently to obtain desired film characteristics. Specifically, depending on the type of acid catalyst used, for example, acetic acid is preferably 15 hours or more at room temperature, and nitric acid is preferably 2 hours or more. The aging temperature affects the aging time. Generally, the aging proceeds quickly at high temperatures, but when heated to 100 ° C. or higher, gelation occurs, so heating at 20 to 60 ° C. and keeping the temperature are appropriate.

  The above-mentioned hollow fine particles and additives are added to the silicate oligomer solution formed by hydrolysis and condensation in this way, and necessary dilution is performed to prepare a low refractive index layer coating solution, which is applied onto the above-described film. By drying, a layer containing an excellent silicon oxide film as a low refractive index layer can be formed.

  In the present invention, in addition to the above alkoxysilane, for example, a modified product modified with a silane 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 used alone or in combination.

<Fluorine compound>
The low refractive index layer used in the present invention preferably contains hollow fine particles and a fluorine compound, and as a binder matrix, a fluorine-containing resin that is crosslinked by heat or ionizing radiation (hereinafter also referred to as “fluorine-containing resin before crosslinking”). including. By including the fluorine-containing resin, a good antifouling antireflection film can be provided.

  Preferred examples of the fluorine-containing resin before crosslinking include a fluorine-containing copolymer formed from a fluorine-containing vinyl monomer and a monomer for imparting a crosslinkable group. Specific examples of the fluorine-containing vinyl monomer unit include, for example, fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3 -Dioxoles, etc.), (meth) acrylic acid partial or fully fluorinated alkyl ester derivatives (for example, Biscoat 6FM (manufactured by Osaka Organic Chemical), M-2020 (manufactured by Daikin), etc.), fully or partially fluorinated vinyl ethers, etc. Is mentioned. As monomers for imparting a crosslinkable group, glycidyl methacrylate, vinyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, vinyl glycidyl ether, and other vinyl monomers having a crosslinkable functional group in advance in the molecule. , Vinyl monomers having a carboxyl group, hydroxyl group, amino group, sulfonic acid group, etc. (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, hydroxyalkyl vinyl ether, hydroxyalkyl allyl) Ether, etc.). The latter can introduce a crosslinked structure after copolymerization by adding a compound that reacts with a functional group in the polymer and one or more reactive groups. No. 147739. Examples of the crosslinkable group include acryloyl, methacryloyl, isocyanate, epoxy, aziridine, oxazoline, aldehyde, carbonyl, hydrazine, carboxyl, methylol, and active methylene group. When the fluorine-containing copolymer is cross-linked by heating by a cross-linking group that reacts by heating, or a combination of an ethylenically unsaturated group and a thermal radical generator or an epoxy group and a thermal acid generator, the thermosetting type In the case of crosslinking by irradiation with light (preferably ultraviolet rays, electron beams, etc.) by a combination of an ethylenically unsaturated group and a photo radical generator, or an epoxy group and a photo acid generator, etc., it is an ionizing radiation curable type. .

  Further, in addition to the above monomers, a fluorine-containing copolymer formed by using a monomer other than the fluorine-containing vinyl monomer and the monomer for imparting a crosslinkable group may be used as the fluorine-containing resin before crosslinking. The monomer that can be used in combination is not particularly limited. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, 2-acrylic acid 2- Ethyl hexyl), methacrylates (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyl toluene, α-methylstyrene, etc.), vinyl ethers (methyl vinyl ether) Etc.), vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate, etc.), acrylamides (N-tertbutylacrylamide, N-cyclohexylacrylamide, etc.), methacrylamides, Ronitoriru derivatives and the like can be mentioned. In addition, it is also preferable to introduce a polyorganosiloxane skeleton or a perfluoropolyether skeleton into the fluorinated copolymer in order to impart slipperiness and antifouling properties. For example, polyorganosiloxane or perfluoropolyether having an acrylic group, methacrylic group, vinyl ether group, styryl group or the like at the terminal is polymerized with the above monomer, and polyorganosiloxane or perfluoropolyester having a radical generating group at the terminal. It can be obtained by polymerization of the above monomers with ether, reaction of a polyorganosiloxane or perfluoropolyether having a functional group with a fluorine-containing copolymer, or the like.

  The proportion of each of the above monomers used to form the fluorinated copolymer before crosslinking is preferably 20 to 70 mol%, more preferably 40 to 70 mol%, more preferably 40 to 70 mol% of the fluorinated vinyl monomer. The amount of the monomer is preferably 1 to 20 mol%, more preferably 5 to 20 mol%, and the other monomer used in combination is preferably 10 to 70 mol%, more preferably 10 to 50 mol%.

  The fluorine-containing copolymer can be obtained by polymerizing these monomers in the presence of a radical polymerization initiator by means such as solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization.

  The fluorine-containing resin before crosslinking is commercially available and can be used. Examples of commercially available fluorine-containing resins before cross-linking include Cytop (Asahi Glass), Teflon (registered trademark) AF (DuPont), polyvinylidene fluoride, Lumiflon (Asahi Glass), OPSTAR (JSR), etc. Can be mentioned.

  The low refractive index layer containing a cross-linked fluororesin as a constituent component preferably has a dynamic friction coefficient in the range of 0.03 to 0.15 and a contact angle with water in the range of 90 to 120 degrees.

<Additive>
If necessary, the low refractive index layer coating solution may further contain additives such as a silane coupling agent and a curing agent. The silane coupling agent is a compound represented by the general formula (2).

  Specific examples include vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and 3- (2-aminoethylaminopropyl) trimethoxysilane.

  Examples of the curing agent include organic acid metal salts such as sodium acetate and lithium acetate, and sodium acetate is particularly preferable. The amount of addition to the silicon alkoxysilane hydrolysis solution is preferably in the range of about 0.1 to 1 part by mass with respect to 100 parts by mass of the solid content present in the hydrolysis solution.

  Moreover, it is preferable to add low surface tension substances such as various leveling agents, surfactants, and silicone oils to the coating solution for the low refractive index layer used in the present invention.

  Specific examples of the silicone oil include L-45, L-9300, FZ-3704, FZ-3703, FZ-3720, FZ-3786, FZ-3501, and FZ-3504 of Nippon Unicar Co., Ltd. , FZ-3508, FZ-3705, FZ-3707, FZ-3710, FZ-3750, FZ-3760, FZ-3785, FZ-3785, Y-7499, Shin-Etsu Chemical KF96L, KF96, KF96H, KF99, KF54 , KF965, KF968, KF56, KF995, KF351, KF352, KF353, KF354, KF355, KF615, KF618, KF945, KF6004, FL100 and the like.

  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. When these components are added in an excessive amount, they cause repelling during coating. Therefore, it is preferable to add them in a range of 0.01 to 3% by mass with respect to the solid component in the coating solution.

<solvent>
Solvents used in the coating solution for coating the low refractive index layer are alcohols such as methanol, ethanol, 1-propanol, 2-propanol and butanol; ketones such as acetone, methyl ethyl ketone and cyclohexanone; benzene, toluene, Aromatic hydrocarbons such as xylene; glycols such as ethylene glycol, propylene glycol, hexylene glycol; ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, diethyl cellosolve, diethyl carbitol, propylene glycol monomethyl Examples include glycol ethers such as ether; N-methylpyrrolidone, dimethylformamide, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, water, etc., and these may be used alone or in combination of two or more. That.

<Application method>
As a method of applying the low refractive index layer, known methods such as dipping, spin coating, knife coating, bar coating, air doctor coating, blade coating, squeeze coating, reverse roll coating, gravure roll coating, curtain coating, spray coating, die coating, etc. A coating method or a known inkjet method can be used, and a coating method capable of continuous coating or thin film coating is preferably used. The coating amount is suitably 0.1 to 30 μm, preferably 0.5 to 15 μm in terms of wet film thickness. The coating speed is preferably 10 to 80 m / min.

  When the composition of the present invention is applied to a substrate, the thickness of the layer, coating uniformity, and the like can be controlled by adjusting the solid content concentration and the coating amount in the coating solution.

  In the present invention, it is also preferable to further provide the following medium refractive index layer and high refractive index layer to form an antireflection layer having a plurality of layers.

  Although the structural example of the antireflection layer which can be used for this invention is shown below, it is not limited to these.

Long film / hard coat layer / low refractive index layer Long film / hard coat layer / medium refractive index layer / low refractive index layer Long film / hard coat layer / high refractive index layer / low refractive index layer Long film / Hard coat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer Long film / Antistatic layer / Hard coat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer Long film / Hard coat Layer / antistatic layer / medium refractive index layer / high refractive index layer / low refractive index layer antistatic layer / long film / hard coat layer / medium refractive index layer / high refractive index layer / low refractive index layer long film / Hard coat layer / high refractive index layer / low refractive index layer / high refractive index layer / low refractive index layer (medium refractive index layer, high refractive index layer)
The medium refractive index layer and the high refractive index layer are not particularly limited as long as a predetermined refractive index layer is obtained, but are preferably composed of metal oxide fine particles, a binder and the like having the following high refractive index. In addition, you may contain an additive. The refractive index of the middle refractive index layer is preferably 1.55 to 1.75, and the refractive index of the high refractive index layer is preferably 1.75 to 2.20. The thickness of the high refractive index layer and the medium refractive index layer is preferably 5 nm to 1 μm, more preferably 10 nm to 0.2 μm, and most preferably 30 nm to 0.1 μm. The coating can be performed in the same manner as the coating method for the low refractive index layer.

<Metal oxide fine particles>
Although metal oxide fine particles are not particularly limited, for example, titanium dioxide, aluminum oxide (alumina), zirconium oxide (zirconia), zinc oxide, antimony-doped tin oxide (ATO), antimony pentoxide, indium-tin oxide (ITO), Iron oxide or the like can be used as a main component. A mixture of these may also be used. When titanium dioxide is used, photocatalytic activity can be achieved by using metal oxide particles having a core / shell structure in which titanium dioxide is the core and the shell is coated with alumina, silica, zirconia, ATO, ITO, antimony pentoxide, or the like. It is preferable in terms of suppression.

  The refractive index of the metal oxide fine particles is preferably 1.80 to 2.60, more preferably 1.90 to 2.50. The average particle diameter of the primary particles of the metal oxide fine particles is 5 nm to 200 nm, more preferably 10 to 150 nm. If the particle size is too small, the metal oxide fine particles tend to aggregate and the dispersibility deteriorates. If the particle size is too large, the haze increases, which is not preferable. The shape of the inorganic fine particles is preferably a rice grain shape, a needle shape, a spherical shape, a cubic shape, a spindle shape or an indefinite shape.

  The metal oxide fine particles may be surface-treated with an organic compound. Examples of the organic compound used for the surface treatment include polyols, alkanolamines, stearic acid, silane coupling agents, and titanate coupling agents. Among these, the silane coupling agent described later is most preferable. Two or more kinds of surface treatments may be combined.

  By appropriately selecting the kind and addition ratio of the metal oxide, a high refractive index layer and a medium refractive index layer having a desired refractive index can be obtained.

<Binder>
The binder is added to improve the film formability and physical properties of the coating film. As the binder, for example, the aforementioned ionizing radiation curable resin, acrylamide derivative, polyfunctional acrylate, acrylic resin or methacrylic resin can be used.

(Metal compounds, silane coupling agents)
As other additives, a metal compound, a silane coupling agent, or the like may be added. Metal compounds and silane coupling agents can also be used as binders.

  As the metal compound, a compound represented by the following general formula (4) or a chelate compound thereof can be used.

General formula (4): AnMBx-n
In the formula, M represents a metal atom, A represents a hydrolyzable functional group or a hydrocarbon group having a hydrolyzable functional group, and B represents an atomic group covalently or ionically bonded to the metal atom M. x represents the valence of the metal atom M, and n represents an integer of 2 or more and x or less.

  Examples of the hydrolyzable functional group A include halogens such as alkoxyl groups and chloro atoms, ester groups and amide groups. The metal compound belonging to the above formula (4) includes an alkoxide having two or more alkoxyl groups bonded directly to a metal atom, or a chelate compound thereof. Preferable metal compounds include titanium alkoxides, zirconium alkoxides, silicon alkoxides, and chelate compounds thereof from the viewpoints of the effect of reinforcing the refractive index and coating film strength, ease of handling, material cost, and the like. Titanium alkoxide has a high reaction rate and a high refractive index and is easy to handle. However, since it has a photocatalytic action, its light resistance deteriorates when added in a large amount. Zirconium alkoxide has a high refractive index but tends to become cloudy, so care must be taken in dew point management during coating. Silicon alkoxide has a slow reaction rate and a low refractive index, but is easy to handle and has excellent light resistance. Since the silane coupling agent can react with both the inorganic fine particles and the organic polymer, a tough coating film can be formed. Moreover, since titanium alkoxide has the effect of accelerating the reaction of the ultraviolet curable resin and metal alkoxide, the physical properties of the coating film can be improved by adding a small amount.

  Examples of the titanium alkoxide include tetramethoxy titanium, tetraethoxy titanium, tetra-iso-propoxy titanium, tetra-n-propoxy titanium, tetra-n-butoxy titanium, tetra-sec-butoxy titanium, tetra-tert-butoxy titanium, and the like. Is mentioned.

  Examples of the zirconium alkoxide include tetramethoxy zirconium, tetraethoxy zirconium, tetra-iso-propoxy zirconium, tetra-n-propoxy zirconium, tetra-n-butoxy zirconium, tetra-sec-butoxy zirconium, tetra-tert-butoxy zirconium and the like. Is mentioned.

  The silicon alkoxide and the silane coupling agent are compounds represented by the following general formula (5).

Formula (5): RmSi (OR ′) n
In the formula, R is an alkyl group (preferably an alkyl group having 1 to 10 carbon atoms), or a reaction such as a vinyl group, a (meth) acryloyl group, an epoxy group, an amide group, a sulfonyl group, a hydroxyl group, a carboxyl group, or an alkoxyl group. R ′ represents an alkyl group (preferably an alkyl group having 1 to 10 carbon atoms), and m + n is 4.

  Specifically, tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, tetrapenta Ethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, hexyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane , Γ-glycidoxypropyltrimethoxysilane, 3- (2-aminoethylaminopropyl) trimethoxysilane and the like.

  Preferred chelating agents for forming a chelate compound by coordination with a free metal compound include alkanolamines such as diethanolamine and triethanolamine, glycols such as ethylene glycol, diethylene glycol and propylene glycol, acetylacetone and acetoacetic acid. Examples thereof include ethyl and the like having a molecular weight of 10,000 or less. By using these chelating agents, it is possible to form a chelate compound that is stable against moisture mixing and is excellent in the effect of reinforcing the coating film.

  The addition amount of the metal compound is preferably less than 5% by mass in terms of metal oxide in the medium refractive index composition, and less than 20% by mass in terms of metal oxide in the high refractive index composition. Is preferred.

(Polarizer)
The polarizing plate according to the present invention can be produced by a general method. The optical film of the present invention can be bonded to both sides of a polarizer produced by subjecting the optical film of the present invention to an alkali saponification treatment and immersing and stretching in an iodine solution as a polarizing plate protective film using a completely saponified polyvinyl alcohol aqueous solution.

  Alternatively, the optical film of the present invention can be bonded to one surface of a polarizer as a polarizing plate protective film with an antireflection layer, and a commercially available polarizing plate protective film or retardation film can be bonded to the opposite surface. . As the commercially available cellulose ester film, for example, Konica Minoltak KC8UX, KC4UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UY, KC12UR (manufactured by Konica Minolta Opto Co., Ltd.) is preferably used.

  The polarizing film, which is the main component of the polarizing plate, is an element that transmits only light having a polarization plane in a certain direction. A typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol film. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed. As the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxially stretching or dyed, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound. An ethylene-modified polyvinyl alcohol film is also preferably used as the polarizing film.

(Display device)
The display device using the optical film or the polarizing plate of the present invention is excellent in durability and can display with high contrast over a long period of time.

  Various display devices can be produced by incorporating the optical film or polarizing plate of the present invention into a display device. Examples of the display device include a liquid crystal display device (reflective type, transflective type, transmissive type), an organic electroluminescence element, a plasma display, and the like. For example, in the forced deterioration treatment under high temperature and high humidity conditions, the optical film or polarizing plate of the present invention was excellent in visibility and no problems caused by the film were observed in the display device.

  Furthermore, by incorporating the polarizing plate of the present invention into a liquid crystal display device, various liquid crystal display devices with excellent visibility can be produced. 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. Used. In particular, a large-screen liquid crystal display device with a 30-inch screen or more has the effect that there is little color unevenness and wavy unevenness, and eyes are not tired even during long-time viewing.

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

(Preparation of dope solution A)
Cellulose ester (cellulose triacetate; acetyl group substitution degree 2.9)
100 parts by mass Trimethylolpropane tribenzoate 5 parts by mass Ethylphthalyl ethyl glycolate 5 parts by mass Silicon oxide fine particles (Aerosil R972V (produced by Nippon Aerosil Co., Ltd.))
0.1 parts by weight Methylene chloride 300 parts by weight Ethanol 40 parts by weight A dope prepared as described above was passed through a casting die kept at 30 ° C. on a 30 ° C. support made of a stainless steel endless belt having a width of 2 m. The web was cast at 8 m to form a web, dried on the support, dried on the support until the residual solvent amount of the web reached 80% by mass, and then peeled from the support with a peeling roll.

  Next, the web is dried with a drying air at 70 ° C. in a conveying and drying process using a plurality of rolls arranged on the top and bottom, and then grips both ends of the web with a tenter, and then is stretched in the width direction at 130 ° C. 1.1 times before stretching. It extended | stretched so that it might become. After stretching with a tenter, the web is dried with a drying air of 135 ° C. in a conveying and drying process using a plurality of rolls arranged above and below, dried to a residual solvent amount of 0.3% by mass, cooled to room temperature, After cutting, a long cellulose ester film having a winding width of 1.5 m, a film thickness of 80 μm, a length of 3000 m, and a refractive index of 1.49 was produced. The draw ratio in the web conveyance direction immediately after peeling calculated from the rotational speed of the stainless steel band support and the operating speed of the tenter was 1.1 times.

(Preparation of optical film with antireflection layer)
Using the produced cellulose ester film, an optical film with an antireflection layer was produced by the following procedure.

  The refractive index of each layer constituting the antireflection layer was measured by the following method.

(Refractive index)
The refractive index of each refractive index layer was determined from the measurement result of the spectral reflectance of a spectrophotometer for a sample in which each layer was coated on the hard coat film prepared below. The spectrophotometer uses U-4000 type (manufactured by Hitachi, Ltd.), and after roughening the back side of the measurement side of the sample, light absorption treatment is performed with black spray to prevent reflection of light on the back side. The reflectance in the visible light region (400 nm to 700 nm) was measured under the condition of regular reflection at 5 degrees.

(Particle size of metal oxide fine particles)
As for the particle diameter of the metal oxide fine particles used, 100 fine particles were observed with an electron microscope (SEM), the diameter of a circle circumscribing each fine particle was taken as the particle diameter, and the average value was taken as the particle diameter.

<< Formation of hard coat layer >>
On the produced cellulose ester film, the following hard coat layer coating solution is filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a hard coat layer coating solution, which is applied using a micro gravure coater, After drying at 90 ° C., an ultraviolet lamp is used to cure the coating layer with an irradiance of 100 mW / cm ² and an irradiation amount of 0.1 J / cm ² to form a hard coat layer having a dry film thickness of 7 μm. A coated film was produced.

(Hard coat layer coating solution)
The following materials were stirred and mixed to obtain a hard coat layer coating solution.

Acrylic monomer: KAYARAD DPHA (dipentaerythritol hexaacrylate, Nippon Kayaku) 220 parts by mass Irgacure 184 (manufactured by Ciba Specialty Chemicals) 20 parts by mass Propylene glycol monomethyl ether 110 parts by mass Ethyl acetate 110 parts by mass << Antireflection layer Fabrication of optical film with adhesive >>
On the hard coat film produced as described above, an antireflection layer was applied in the order of a high refractive index layer and then a low refractive index layer as described below to produce an optical film with an antireflection layer.

<Formation of antireflection layer: high refractive index layer>
On the hard coat film, the following high refractive index layer coating composition was applied with an extrusion coater, dried at 80 ° C. for 1 minute, then cured by irradiation with ultraviolet rays of 0.1 J / cm ² , and further at 100 ° C. for 1 minute. A high refractive index layer was provided so as to have a thickness of 78 nm by thermosetting.

  The refractive index of this high refractive index layer was 1.62.

<High refractive index layer coating composition>
Isopropyl alcohol solution of metal oxide fine particles (solid content 20%, ITO particles, particle size 5 nm) 55 parts by mass Metal compound: Ti (OBu) ₄ (tetra-n-butoxytitanium) 1.3 parts by mass Ionizing radiation curable resin : Dipentaerythritol hexaacrylate 3.2 parts by mass Photopolymerization initiator: Irgacure 184 (manufactured by Ciba Specialty Chemicals)
0.8 parts by mass 10% propylene glycol monomethyl ether solution of linear dimethyl silicone-EO block copolymer (FZ-2207, manufactured by Nippon Unicar Co., Ltd.) 1.5 parts by mass Propylene glycol monomethyl ether 120 parts by mass Isopropyl alcohol 240 parts by mass Methyl ethyl ketone 40 parts by mass << Formation of antireflection layer: low refractive index layer >>
On the high refractive index layer, the following low refractive index layer coating composition is applied with an extrusion coater 3 using the apparatus shown in FIG. 1, dried at 100 ° C. in the first drying zone 5 for 1 minute, and then activated. The ultraviolet ray is irradiated by 0.1 J / cm ² with a line lamp 6a and cured, and the optical film with the antireflection layer is wound around a heat-resistant plastic core with the apparatus shown in FIG. Was wound up at 20 m / min, and then heat treatment and rewinding were performed at 100 m / min to produce an optical film 1 with an antireflection layer.

  The low refractive index layer had a thickness of 95 nm and a refractive index of 1.37.

(Preparation of low refractive index layer coating composition)
<Preparation of tetraethoxysilane hydrolyzate A>
Hydrolyzate A was prepared by mixing 289 g of tetraethoxysilane and 553 g of ethanol, adding 157 g of 0.15% aqueous acetic acid solution thereto, and stirring in a water bath at 25 ° C. for 30 hours.

Tetraethoxysilane hydrolyzate A 110 parts by mass Hollow silica-based fine particles (P-2 below) 30 parts by mass KBM503 (silane coupling agent, manufactured by Shin-Etsu Chemical Co., Ltd.) 4 parts by mass Linear dimethyl silicone-EO block copolymer (FZ) -2207, manufactured by Nihon Unicar Co., Ltd.) 10% propylene glycol monomethyl ether solution 3 parts by mass Propylene glycol monomethyl ether 400 parts by mass Isopropyl alcohol 400 parts by mass <Preparation of hollow silica-based fine particles P-2>
A mixture of 100 g of silica sol having an average particle diameter of 5 nm and a SiO ₂ concentration of 20% by mass and 1900 g of pure water was heated to 80 ° C. The pH of this reaction mother liquor was 10.5, and 9000 g of 0.98 mass% sodium silicate aqueous solution as SiO ₂ and 9000 g of 1.02 mass% sodium aluminate aqueous solution as Al ₂ O ₃ were simultaneously added to the mother liquor. did. Meanwhile, the temperature of the reaction solution was kept at 80 ° C. The pH of the reaction solution rose to 12.5 immediately after the addition and hardly changed thereafter. After completion of the addition, the reaction solution was cooled to room temperature and washed with an ultrafiltration membrane to prepare a SiO ₂ .Al ₂ O ₃ core particle dispersion having a solid content concentration of 20% by mass. (Process (a))
1700 g of pure water is added to 500 g of this core particle dispersion and heated to 98 ° C., and while maintaining this temperature, a silicic acid solution (SiO ₂₎ obtained by dealkalizing a sodium silicate aqueous solution with a cation exchange resin. A dispersion of core particles in which 3000 g (concentration of 3.5% by mass) was added to form a first silica coating layer was obtained. (Process (b))
Next, 1125 g of pure water is added to 500 g of the core particle dispersion liquid that has been washed with an ultrafiltration membrane to form a first silica coating layer having a solid concentration of 13% by mass, and concentrated hydrochloric acid (35.5%) is further added dropwise. The pH was adjusted to 1.0 and dealumination was performed. Next, the aluminum salt dissolved in the ultrafiltration membrane was separated while adding 10 L of hydrochloric acid aqueous solution of pH 3 and 5 L of pure water, and SiO ₂ · Al from which some of the constituent components of the core particles forming the first silica coating layer were removed. A dispersion of ₂ O ₃ porous particles was prepared (step (c)). A mixture of 1500 g of the above porous particle dispersion, 500 g of pure water, 1,750 g of ethanol, and 626 g of 28% ammonia water is heated to 35 ° C., and then 104 g of ethyl silicate (SiO ₂ 28 mass%) is added. The surface of the porous particles on which the first silica coating layer was formed was coated with a hydrolyzed polycondensate of ethyl silicate to form a second silica coating layer. Subsequently, a dispersion of hollow silica-based fine particles (P-2) having a solid content concentration of 20% by mass in which the solvent was replaced with ethanol using an ultrafiltration membrane was prepared.

The thickness of the first silica coating layer of the hollow silica-based fine particles was 3 nm, the average particle size was 47 nm, MOx / SiO ₂ (molar ratio) was 0.0017, and the refractive index was 1.28. Here, the average particle diameter was measured by a dynamic light scattering method.

  In the same manner as in the optical film 1, under the conditions described in Table 1, winding-up conditions, heat treatment conditions, cooling or rewinding were performed to prepare optical films 2 to 17 with an antireflection layer.

  The following evaluation was implemented about the obtained optical films 1-17 with an antireflection layer.

(Reflective color unevenness variation within lot)
Five samples of the center part of 500 m, 1000 m, 1500 m, 2000 m, and 2500 m in length were collected from the start of application of the low refractive index layer of the optical film roll, and the reflection color unevenness of the five samples was visually evaluated. . The evaluation criteria were as follows and evaluated in 6 stages. If it is Δ level or more, there is no problem in practical use, but it is preferably not less than ○ Δ level, and most preferably ◎ level.

◎: Color variation of reflected light is not observed at all ○: Color variation of reflected light is hardly recognized ○ △: Color variation of reflected light is slightly observed △: Color variation of reflected light is partially recognized △ ×: Reflected light color variation is recognized as a whole ×: Reflected light color tone variation is recognized as a whole (reflective color unevenness variation among lots)
Under the same conditions, five optical films with antireflection layers 3000m (5 lots) are manufactured, and 500m, 1000m, 1500m, 2000m, 2500m long central samples from the start of low refractive index layer application of each optical film roll. The sample was collected, and the reflectance was measured by the following method to determine the average reflectance. Further, the dispersion of the average reflectance among the 5 lots was determined according to the following criteria.

○: No variation in average reflectance observed in 5 lots of samples Δ: Some variation in average reflectance observed in 5 lots of samples ×: Large variation in average reflectance between 5 lots of samples <Reflectance measurement Method>
The spectral reflectance of the antireflection film was measured using a spectrophotometer U-4000 type (manufactured by Hitachi, Ltd.) under the condition of regular reflection at 5 degrees. The measurement is performed by roughening the back surface on the observation side, and then performing light absorption treatment using a black spray, preventing reflection of light on the back surface of the film, and measuring the reflectivity to be 450 nm to 650 nm. The average reflectance of the wavelength was determined.

  The above evaluation results are shown in Table 2.

  From Table 2, it can be seen that in the optical films 5 to 11 and 14 to 17 of the present invention, the reflection color unevenness within the lot and the reflection color unevenness among the lots are superior to the comparative example.

  In particular, the optical films 15 and 16 of the present invention, in which warm air is blown at the time of winding, followed by heat treatment, and further cooled by rewinding while adjusting the humidity, have extremely good variations in the reflection color unevenness. I understand.

Example 2
Next, using the optical films 1 to 17 with an antireflection layer prepared in Example 1, polarizing plates are prepared as follows, and these polarizing plates are incorporated into a liquid crystal display panel (image display device) to improve visibility. evaluated.

  In accordance with the following method, a polarizing plate was prepared using each of the above optical films 1 to 17 with an antireflection layer and one KC8UCR-5 (manufactured by Konica Minolta Opto) as a polarizing plate protective film. Produced.

(A) Production of polarizing film 100 parts by mass of polyvinyl alcohol (hereinafter abbreviated as PVA) having a saponification degree of 99.95 mol% and a polymerization degree of 2400 was melt-kneaded with 10 parts by mass of glycerin and 170 parts by mass of water. After defoaming, the film was melt extruded from a T die onto a metal roll to form a film. Then, it dried and heat-processed and obtained the PVA film. The obtained PVA film had an average thickness of 40 μm, a moisture content of 4.4%, and a film width of 3 m.

  The aforementioned PVA film was processed in the order of pre-swelling, dyeing, uniaxial stretching by a wet method, fixing treatment, drying, and heat treatment to produce a polarizing film. The PVA film was pre-swelled by immersing it in water at 30 ° C. for 30 seconds and immersed in an aqueous solution at 35 ° C. having an iodine concentration of 0.4 g / liter and a potassium iodide concentration of 40 g / liter for 3 minutes. Subsequently, the film was uniaxially stretched 6 times in an aqueous solution of boric acid concentration 4% at 50 ° C. under a tension of 700 N / m. The potassium iodide concentration 40 g / liter, boric acid concentration 40 g / liter, Fixation was performed by immersing in an aqueous solution at 30 ° C. with a zinc chloride concentration of 10 g / liter for 5 minutes. Thereafter, the PVA film was taken out, dried with hot air at 40 ° C., and further subjected to heat treatment at 100 ° C. for 5 minutes. The obtained polarizing film had an average thickness of 13 μm, and the polarizing performance was a transmittance of 43.0%, a polarization degree of 99.5%, and a dichroic ratio of 40.1.

(B) Production of Polarizing Plate Next, according to the following Steps 1 to 5, the polarizing film and the polarizing plate protective film were bonded together to produce a polarizing plate.

  Step 1: The optical compensation film and the optical films 1 to 17 with an antireflection layer were immersed in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried. A surface of the optical films 1 to 17 with the antireflection layer provided with the antireflection layer was previously protected by attaching a peelable protective film (made of PET).

  Similarly, the optical compensation film was immersed in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried.

  Process 2: The above-mentioned polarizing film was immersed for 1 to 2 seconds in the polyvinyl alcohol adhesive tank of 2 mass% of solid content.

  Step 3: Excess adhesive adhered to the polarizing film in Step 2 was lightly removed, and it was sandwiched between the optical compensation film subjected to alkali treatment in Step 1 and the optical films 1 to 17 with an antireflection layer, and laminated.

Process 4: It bonded together at the speed | rate of about 2 m / min with the pressure of 20-30 N / cm < ² > with the two rotating rollers. At this time, care was taken to prevent bubbles from entering.

  Step 5: The sample prepared in Step 4 in a dryer at 80 ° C. was dried for 2 minutes to prepare polarizing plates 1 to 17.

  A polarizing plate on the outermost surface of a commercially available liquid crystal display panel (VA type) was carefully peeled off, and polarizing plates 1 to 17 having the same polarization direction were attached thereto.

  The liquid crystal display panels 1 to 17 obtained as described above were placed on a desk 80 cm high from the floor, and a daylight direct fluorescent lamp (FLR40S • D / M-) was placed on the ceiling 3 m high from the floor. X: Matsushita Electric Industrial Co., Ltd.) 40W × 2 were used as one set, and 10 sets were arranged at 1.5 m intervals. At this time, when the evaluator is in front of the display surface of the liquid crystal display panel, the fluorescent lamp is arranged so that the fluorescent lamp comes to the ceiling from the evaluator's overhead to the rear. The liquid crystal display panel was tilted by 25 ° from the vertical direction with respect to the desk, and a fluorescent lamp was reflected so that the visibility of the screen (visibility) was evaluated as follows.

A: You don't have to worry about the movement of the nearest fluorescent light, and you can clearly read characters with a font size of 8 or less. B: The reflection of the nearby fluorescent light is a little worrisome, but you don't care about the distance. Can manage to read characters with a font size of 8 or less C: It is difficult to read characters with a font size of 8 or less. Anxious, the portion of the reflection can not read the characters of the font size of 8 or less As a result of the evaluation, the optical films 5-11, 14-17 with the antireflection layer of the present invention, the polarizing plate 5 of the present invention The liquid crystal display panels 5 to 11 and 14 to 17 of the present invention using 11 and 14 to 17 were all B or more evaluation results, and the visibility was better than the comparative sample.

Example 3
A cellulose ester film and an optical film with an antireflection layer were produced in the same manner as in Example 1 except that the film thickness of the cellulose ester film produced in Example 1 was set to 40 μm. A polarizing plate and a liquid crystal display panel were prepared, and the same evaluations as in Example 1 and Example 2 were performed.

  As a result, the sample of the configuration of the present invention reproduced Example 1 and Example 2 well, and was excellent in reflection color unevenness within lots, lot-to-lot variations, and liquid crystal display device visibility.

It is the schematic which showed the coating of the present invention, the drying process, the subsequent heat treatment (aging), and the process of rewinding. It is a schematic diagram of the winding core part preferable for this invention.

Explanation of symbols

Y long film 1 feeding roll 2 transport roller 3 extrusion coater 4 counter roller 5 first drying zone 6 actinic ray irradiation lamp unit 6a air cooling actinic ray lamp 6b air cooling air vent 6c N ₂ supply chamber 7 second drying zone 8 Winding chamber 9 Winding roll 10 Hot air outlet 11 Aging zone 12 Aged roll 13 Rewinding zone 14 Rewinding roll 15 Winding core 16 Core support shaft 17 Core chuck 18 Heat retaining water 19 Heating zone

Claims (9)

In the manufacturing method of the optical film which provides a functional thin film on a long film, it has the process of conveying a long film continuously and coating a functional thin film, and after coating, this optical film is temperature 50 degreeC or more. A method for producing an optical film, which is wound up in a roll and subsequently subjected to heat treatment at 50 ° C. or more for 1 day or more. The method for producing an optical film according to claim 1, wherein the functional thin film is an antireflection layer. When winding up the optical film in a roll shape, the atmospheric temperature of the winding chamber is 50 to 150 ° C, or winding is performed while applying hot air of 50 ° C or higher to the winding roll. The manufacturing method of the optical film of 1 or 2. It has a step of coating a functional thin film by continuously transporting a long film. After coating, the optical film is wound up in a roll and subjected to heat treatment at 50 ° C. or more for 1 day or more. A method for producing an optical film, wherein the film is cooled while rewinding after completion of the treatment. 5. The method for producing an optical film according to claim 4, wherein the optical film after completion of the heat treatment is passed through an atmosphere having a relative humidity of 10 to 70% RH while being wound, or is wound up in the atmosphere. An optical film manufactured by the method for manufacturing an optical film according to claim 1. The optical film according to claim 6, wherein the optical film has a low refractive index layer containing hollow fine particles. A polarizing plate using the optical film according to claim 6 or 7 on at least one surface. A display device comprising the polarizing plate according to claim 8.

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