JP6676930B2 - Optical film - Google Patents

Description

  The present invention relates to an optical film. More specifically, the present invention relates to an optical film or the like in which when an optical film is used as a protective film for a polarizing plate, the generation of cracks and chips when punching the polarizing plate is reduced.

  Conventionally, when a polarizing plate was cut for a liquid crystal display device, the shape was rectangular.However, from the viewpoint of improving design, in recent years, displays with polygons and curves have been used in in-vehicle displays such as car navigation systems. It is necessary to cut the polarizing plate so as to correspond to various shapes.

  Further, since a display mounted on a vehicle is exposed to a severe environment such as high temperature and high humidity, an optical film using a resin having excellent heat resistance and moisture resistance such as a cycloolefin resin film is preferably used.

  When cutting the above-mentioned polarizing plate into a shape other than a rectangle, it is necessary to perform punching with a free form. There is a problem that cracks such as cracks and cracks are generated and chips are easily generated by cutting, and this problem becomes more serious as the thickness of the polarizing plate is reduced.

  Generally, a matting agent (fine particles) such as silica particles is preferably used for improving the handling property in a film manufacturing process and a processing process. However, silica particles are easily aggregated in a cycloolefin resin, and the aggregated silica particles are polarized. When a plate is punched, the crack tends to be a starting point.

  Patent Literature 1 describes an example in which fine particles of a matting agent are contained in a cycloolefin-based resin film. Although it is possible to improve the handleability by the technique, cracks at the time of punching with the free form can be achieved. And it was not enough to reduce the generation of cuttings.

JP 2007-98843 A

  The present invention has been made in view of the above-described problems and circumstances, and a problem to be solved is to reduce the occurrence of cracks and chips when punching a polarizing plate when using an optical film as a protective film for the polarizing plate. It is to provide an improved optical film.

  In order to solve the above problems, the present inventor, in a process of examining the cause of the above problems, etc., has a cycloolefin resin having at least one hydrogen bond accepting group, an alcohol solvent, a hindered phenol compound, and methanol. The degree of hydrophobicity measured by the wettability method, the optical film containing a specific amount of silica particles satisfying a specific range, when the optical film is used as a protective film of the polarizing plate, cracks and the like when punching the polarizing plate. It has been found that an optical film with reduced generation of chips can be obtained.

  That is, the above object according to the present invention is solved by the following means.

1. An optical film containing a cycloolefin-based resin,
The cycloolefin-based resin is a cycloolefin-based resin having at least one hydrogen bond-accepting group,
The film contains an alcohol solvent in a range of 10 to 1000 ppm, a hindered phenol compound in a range of 0.1 to 0.5% by mass , and
The degree of hydrophobicity measured by the methanol wettability method is such that when the first solution having a volume ratio of methanol to pure water of 3: 7 is used, the degree of hydrophobicity is 20% or less, and the volume of methanol and pure water is not more than 20%. Optics characterized by containing silica particles having a hydrophobicity of 80% or more when the second solution having a ratio of 6: 4 is used is 0.1 to 2.5% by mass based on the total mass of the film. the film.

  2. 2. The optical film according to claim 1, wherein the silica particles have a secondary average particle size in a range of 100 to 400 nm.

3. The film thickness d of the optical film is 5 μm ≦ d ≦ 40 μm, and the in-plane retardation Ro and the thickness direction retardation Rt at a measurement wavelength of 590 nm are Ro ≦ 5 nm and −15 nm ≦ Rt ≦ 15 nm, respectively. 3. The optical film according to item 1 or 2.

4. An optical film containing a cycloolefin-based resin,
The cycloolefin-based resin is a cycloolefin-based resin having at least one hydrogen bond-accepting group,
The film contains an alcohol-based solvent and a hindered phenolic compound, and further contains water in a range of 50 to 500 ppm, and
The degree of hydrophobicity measured by the methanol wettability method is such that when the first solution having a volume ratio of methanol to pure water of 3: 7 is used, the degree of hydrophobicity is 20% or less, and the volume of methanol and pure water is not more than 20%. Optics characterized by containing silica particles having a hydrophobicity of 80% or more when the second solution having a ratio of 6: 4 is used is 0.1 to 2.5% by mass based on the total mass of the film. the film.

5. The optical film according to claim 4, wherein a secondary average particle diameter of the silica particles in the film is in a range of 100 to 400 nm .
6. The film thickness d of the optical film is 5 μm ≦ d ≦ 40 μm, and the in-plane retardation Ro and the thickness direction retardation Rt at a measurement wavelength of 590 nm are Ro ≦ 5 nm and −15 nm ≦ Rt ≦ 15 nm, respectively. Item 6. The optical film according to item 4 or 5 .

  By the above means of the present invention, it is possible to provide an optical film in which, when the optical film is used as a protective film for a polarizing plate, the generation of cracks and chips when punching the polarizing plate is reduced.

  Although the mechanism of manifesting or acting the effects of the present invention has not been clarified, it is speculated as follows.

  The technique of containing the matting agent fine particles disclosed in Patent Document 1 can improve the handleability, but is insufficient to reduce the generation of cracks and chips when punching with a free form. Was.

  Therefore, the present inventors have found that by including a specific compound in an optical film made of a cycloolefin-based resin, it is possible to obtain an optical film which is excellent in handling in the manufacturing process and in which cracks and chips are reduced when punching a polarizing plate. Was found.

  The optical film of the present invention has a cycloolefin resin having at least one hydrogen bond accepting group, an alcohol solvent, a hindered phenol compound, and a degree of hydrophobicity measured by a methanol wettability method, having a specific range. It is a feature that the optical film contains a specific amount of silica particles to be filled. With the optical film having such a configuration, when used as a protective film for a polarizing plate, the interaction between the resin and the matting agent can be maintained, so that the strength of the film is increased, and cracks and chips at the time of punching the polarizing plate are reduced. It has been found that generation can be reduced.

  Generally, cycloolefin-based resin is a hydrophobic resin, so it is not preferable from the viewpoint of transparency because it easily separates when there is moisture when formed into a film, but the cycloolefin-based resin used in the present invention is at least one. Because it is formed from a resin composition containing a hydrogen bond-accepting group, it can form a hydrogen bond with a hydroxy group of an alcohol or a hydroxy group of a hindered phenol compound, so that even if it contains a little water, the transparency is also high. It is characterized in that it can be maintained, and conversely, the film strength is improved by hydrogen bonding.

  This is because the resin interacts with the alcohol in the film, the polar component on the surface of the silica particles, and the hydroxy group of the hindered phenolic compound, and further, through the water molecules in the air taken in from outside the film system. As described above, it is presumed that the strength of the film increases.

  In addition, by adding a hindered phenolic compound, the compound functions as an agglomeration inhibitor, suppresses aggregation of silica particles in the cycloolefin resin film, and appropriately adjusts the secondary particle size of the silica particles in the film. It was also found that it could be controlled within a certain range.

  As an index of the interaction, the degree of hydrophobicity of the silica particles can be used as a scale. By containing a specific amount of the silica particles whose hydrophobicity satisfies a specific range, a resin and a matting agent, a matting agent and an alcohol , And also promoted the interaction between the matting agent and the hindered phenol compound, thereby further improving the film strength.

  That is, when the hydrophobicity of silica particles is determined using a first solution of methanol and pure water at a volume ratio of 3: 7, if the hydrophobicity is 20% or less, a matting agent and a cycloolefin-based It has excellent compatibility with the resin, and in the presence of the hindered phenol compound, the particles are less likely to aggregate, so that the number of crack sources is reduced. Similarly, when the hydrophobicity of silica particles is determined using a second solution of methanol and pure water at a volume ratio of 6: 4, if the hydrophobicity is 80% or more, the matting agent and the alcohol It is presumed that the silica particles in the dope are less likely to aggregate due to the interaction, and that the generation of cracks and chips is reduced by reducing the number of crack sources. Therefore, the polarizing plate using the film can suppress the occurrence of problems such as generation of cracks and chips when punching the polarizing plate.

Schematic diagram showing an example of a dope preparation step, a casting step, a drying step and a winding step of a preferred solution casting film forming method of the present invention.

The optical film of the present invention is an optical film containing a cycloolefin-based resin, wherein the cycloolefin-based resin is a cycloolefin-based resin having at least one hydrogen bond-accepting group, and an alcohol-based solvent is contained in the film. Is contained within the range of 10 to 1000 ppm, the hindered phenol compound is contained within the range of 0.1 to 0.5% by mass , and the degree of hydrophobicity measured by the methanol wettability method is methanol. And pure water have a hydrophobicity of not more than 20% when the first solution having a volume ratio of 3: 7 is used, and methanol and pure water have a hydrophobicity of not more than 20% when a second solution having a volume ratio of 6: 4 is used. The silica film having a hydrophobicity of 80% or more is contained in an amount of 0.1 to 2.5% by mass based on the total mass of the film. When used in protective film, it is possible to provide an optical film that reduces the occurrence of cracks and chips during punching of the polarizing plate.

This feature is a technical feature common to the inventions according to claims 1 to 6 .

  As an embodiment of the present invention, from the viewpoint of the effect manifestation of the present invention, it is preferable that the secondary average particle diameter of the silica particles in the film is in the range of 100 to 400 nm. From the viewpoint of improving the particle size and reducing the generation of cracks and chips when punching the polarizing plate.

During off Irumu, the alcohol solvent comprises in the range of 10-1000 ppm, the hindered phenolic compound, may contain in the range of 0.1 to 0.5 wt%, and said matting agent In the interaction, the content is necessary from the viewpoint of exhibiting the effect of the present invention of improving the film strength.

As the residual solvent component contained in the resin composition, in addition to the alcohol solvent, preferably contain more water. The content of Ru 50~500ppm der. If 50ppm or more, but mechanical strength and brittleness of the obtained film is improved, Ru der 500ppm or less from the viewpoint of transparency of the film. Here, the water includes tap water, deionized water, ultrapure water, distilled water and the like, and preferably distilled water from the viewpoint of productivity such as impurities and cost.

  The thickness d of the optical film is 5 μm ≦ d ≦ 40 μm, and the in-plane phase difference Ro and the thickness direction phase difference Rt at the measurement wavelength of 590 nm are Ro ≦ 5 nm and −15 nm ≦ Rt ≦ 15 nm, respectively. However, when used as a protective film for a polarizing plate, it is preferable from the viewpoint that a lightweight and thin polarizing plate can be provided, and an optimum retardation can be given as a polarizing plate for an IPS mode liquid crystal display device.

  Further, the optical film of the present invention is formed by a solution casting film forming method, and further comprises a cycloolefin resin having the at least one hydrogen bond accepting group, silica particles satisfying the degree of hydrophobicity, and the hindered It is a preferable production method to prepare a dope containing a phenolic compound and an organic solvent including an alcoholic solvent at a dissolution temperature of 15 to 50 ° C.

  When the dissolution temperature is 15 ° C. or higher, the resin and additives can be sufficiently dissolved, so that a film with less foreign matter can be obtained. In addition, when the temperature is 50 ° C. or less, the effect of suppressing coloring by adding silica particles having a good affinity with alcohol is preferable from the viewpoint that the doping due to the reaction of the alcohol and the hindered phenol compound and the coloring of the obtained film can be suppressed. There is.

  Further, it is more preferable to use a combination of an alcoholic solvent having a hydroxy group and water from the viewpoint of improving productivity.

  Since water has a plurality of hydrogen bonding donor groups in one molecule, water can be preferably used to increase the strength of the film. It is preferable that water contains 0.1 to 1% by mass based on the total amount of the solvent. When the content is 0.1% by mass or more, it is preferable because it easily interacts with another alcohol-based solvent or a cycloolefin-based resin or a silica particle containing a hydrogen bond-accepting group. The cycloolefin-based resin gels, and foreign matter is easily generated.

  Hereinafter, the present invention, its components, and embodiments and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning including the numerical value described before and after it as a lower limit and an upper limit.

<< Outline of Optical Film of the Present Invention >>
The optical film of the present invention is an optical film containing a cycloolefin-based resin, wherein the cycloolefin-based resin is a cycloolefin-based resin having at least one hydrogen bond-accepting group, and an alcohol-based solvent is contained in the film. Is contained within the range of 10 to 1000 ppm, the hindered phenol compound is contained within the range of 0.1 to 0.5% by mass , and the degree of hydrophobicity measured by the methanol wettability method is methanol. And pure water have a hydrophobicity of not more than 20% when the first solution having a volume ratio of 3: 7 is used, and methanol and pure water have a hydrophobicity of not more than 20% when a second solution having a volume ratio of 6: 4 is used. The film is characterized by containing 0.1 to 2.5% by mass of the silica particles having a hydrophobicity of 80% or more based on the total mass of the film.

<Methanol wettability method>
The degree of hydrophobicity of the silica particles according to the present invention can be determined using a solvent containing an alcohol-based solvent, pure water, or the like. As a method for quantifying the degree of hydrophobicity, a methanol wettability method (hereinafter, referred to as “MW method”) is preferable. In the present invention, the degree of hydrophobicity is represented by a methanol wettability value (hereinafter, referred to as “MW value”) determined by the present method.

  In the above-mentioned MW method, in order to quantify the degree of hydrophobicity of the fine particles, a first solution and a second solution in which methanol and pure water are mixed are used. At this time, the mixing ratio of methanol to pure water is 3: 7 in the first solution and 6: 4 in the second solution. Then, the same amount of the fine particles is added to each solution and stirred and mixed. Each mixed solution is centrifuged to determine the volume of the precipitate of the fine particles, and the volume of the precipitate of the fine particles in the first solution is determined. MW value in the first solution = (t / A) × 100 [%], and MW value in the second solution, where tmL and the volume of the sediment of the fine particles in the second solution were smL. = (S / A) x 100 [%]. Here, A is the volume (AmL) of the silica particles added first.

[MW method]
(1) A first solution A is prepared by mixing a methanol solution C and pure water D at a volume ratio of 3: 7 (for example, 40 ml of methanol solution C and pure water D 60mL)
(2) Next, 0.2 g of the silica particle powder E and 7 mL of the first solution A are put into a 10 mL settling tube F.
(3) Cap the sedimentation tube F, and shake and mix the fine particle powder E into the first solution A using a Turbula mixer. At this time, the condition of the turbulator mixer is 90 rpm for 30 seconds.
(4) A centrifugal separator is used to settle the silica particle powder E. The condition of the centrifuge is 3500 rpm for 10 minutes.
(5) The volume of the sediment amount of the settled fine particle powder E that can be read on the scale of the sedimentation tube is read, and the value is set to tmL.
(6) A second solution B is prepared by newly mixing the methanol solution C and the pure water D so that the volume ratio becomes 6: 4 (for example, the methanol solution C is pure (Water D is 40 mL).
(7) Using the second solution B, prepare a precipitate of the silica particle powder E by the same procedure (8) to (11) as in the above (2) to (5), and read it on the scale of the sedimentation tube. The amount of sediment of the precipitated silica particle powder E is read as a volume, and the value is defined as smL.
(12) The MW value (%) is obtained by the following equation.

MW value in first solution = (t / A) × 100 [%]
MW value in second solution = (s / A) × 100 [%]
Here, A is the volume (AmL) of the silica particles added first.

For example, if the volume of the sediment of fine particles obtained when using the first solution A is 1 mL and the volume (AmL) of the silica particles added first is 5 mL,
The MW value in the first solution = (1/5) × 100 [%], and the MW value of the hydrophobicity is 20%.

<Configuration of Optical Film of the Present Invention>
[1] Cycloolefin Resin As an embodiment of the present invention, it is preferable to contain water as a solvent component from the viewpoint of improving productivity, and it is preferable that the finished film also contains water.

  Generally, since cycloolefin resin is a hydrophobic resin, it is not preferable from the viewpoint of transparency because it is easy to separate when there is moisture when formed into a film, but the cycloolefin resin used in the present invention is at least one. Since it is formed from a resin composition containing two hydrogen bond-accepting groups, it can form a hydrogen bond with a hydroxy group of an alcohol or a hydroxy group of a hindered phenol compound, so that even if it contains a little water, it is transparent. And the strength of the film is improved by hydrogen bonding. “Hydrogen bond accepting group” refers to a functional group that accepts a hydrogen atom when forming a hydrogen bond.

  The cycloolefin-based resin according to the present invention is characterized by being formed from a resin composition containing at least one hydrogen bond-accepting group.

  Examples of the hydrogen bond-accepting group include an alkoxy group having 1 to 10 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, an allyloxycarbonyl group, a cyano group, and an amide. Groups, an imide ring-containing group, a triorganosiloxy group, a triorganosilyl group, an acyl group, an alkoxysilyl group having 1 to 10 carbon atoms, a sulfonyl-containing group, and a carboxy group. More specifically describing these polar groups, examples of the alkoxy group include a methoxy group and an ethoxy group; examples of the acyloxy group include an alkylcarbonyloxy group such as an acetoxy group and a propionyloxy group; And an arylcarbonyloxy group such as a benzoyloxy group; examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group; examples of the allyloxycarbonyl group include a phenoxycarbonyl group and a naphthyloxycarbonyl group; Group, fluorenyloxycarbonyl group, biphenylyloxycarbonyl group and the like; triorganosiloxy group includes, for example, trimethylsiloxy group and triethylsiloxy group; and triorganosilyl group Trimethylsilyl group, triethylsilyl group and the like; the alkoxysilyl group, for example, trimethoxysilyl groups, triethoxysilyl group, and the like.

  Although the amount of the cycloolefin-based resin containing the hydrogen bond-accepting group contained in the resin component is not particularly limited, the content is preferably 10 to 100% by mass. When the content is 10% by mass or more, the obtained ring-opened copolymer tends to exhibit solubility in a solvent such as toluene or dichloromethane, which is preferable. From the viewpoints of solubility, film strength, and transparency, 30 to 100% is preferable. It is more preferable that the content be in the range of mass%.

  Examples of the cycloolefin-based resin according to the present invention include the following (co) polymers.

[In the formula, p is 0 or 1, and m is 0 or an integer of 1 or more. R ^{1 to} R ⁴ each independently represent a hydrogen atom, a hydrocarbon group, a halogen atom, or a hydrogen bond-accepting group. Further, two or more of R ^{1 to} R ⁴ may be bonded to each other to form an unsaturated bond, a monocyclic or polycyclic ring, and the monocyclic or polycyclic ring has a double bond. Or an aromatic ring may be formed. ]
In the present invention, the cycloolefin-based resin preferably has a preferred hydrogen bond-accepting group holding ratio in which 1 to 2 of R ^{1 to} R ^{4 in} the general formula (I) have a hydrogen bond-accepting group.

Further, the holding ratio of the hydrogen bond-accepting group of the cycloolefin-based resin can be identified, for example, by using a carbon-13 nuclear magnetic resonance ( ¹³ CNMR) spectrum method.

Further, in the general formula (I), R ¹ and R ³ are a hydrogen atom or a hydrocarbon group having 1 to 10, more preferably 1 to 4, and particularly preferably 1 to ^2, and at least one of R ² and R ⁴ One shows a hydrogen bond-accepting group having a polarity other than a hydrogen atom and a hydrocarbon group, and p and m are m = 1 and p = 0 from the viewpoint that the glass transition temperature is high and the mechanical strength is excellent. Some are preferred.

  Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom. Examples of the hydrocarbon group having 1 to 30 carbon atoms include alkyl groups such as methyl group, ethyl group and propyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; alkenyl groups such as vinyl group, allyl group and propenyl group. Groups; aromatic groups such as phenyl, biphenyl, naphthyl, and anthracenyl groups. These hydrocarbon groups may be substituted, and examples of the substituent include a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom, and a phenylsulfonyl group.

The preferred molecular weight of the cycloolefin resin according to the present invention is 0.2 to ⁵ cm ³ / g, more preferably 0.3 to ³ cm ³ / g, particularly preferably 0.4 to 1. a 5 cm ³ / g, number average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) (Mn) is 8,000 to 100,000, more preferably 10,000 to 80,000, particularly preferably from 12,000 to 50,000, a weight average The molecular weight (Mw) is preferably from 20,000 to 300,000, more preferably from 30,000 to 250,000, and particularly preferably from 40,000 to 200,000.

  When the intrinsic viscosity [η] inh, the number average molecular weight and the weight average molecular weight are in the above ranges, the heat resistance, water resistance, chemical resistance, and mechanical properties of the cycloolefin resin, and the cycloolefin resin film according to the present invention Molding processability becomes good.

  The glass transition temperature (Tg) of the cycloolefin-based resin according to the present invention is usually 110 ° C or higher, preferably 110 to 350 ° C, more preferably 120 to 250 ° C, and particularly preferably 120 to 220 ° C. A Tg of 110 ° C. or higher is preferable because deformation under secondary processing such as use under high-temperature conditions or coating and printing is suppressed. In addition, it is preferable that the Tg is 350 ° C. or lower, because resin deterioration due to molding processing and heat during molding processing is suppressed.

  Commercially available products can be preferably used as the cycloolefin-based resin described above. Examples of the commercially available products are sold under the trade names Arton G, Arton F, Arton R, and Arton RX from JSR Corporation. And they can be used.

[2] Silica Particles In the optical film of the present invention, while the manufactured film is handled, it is possible to prevent the film from being damaged or the transportability from deteriorating, and to use the optical film as a protective film for a polarizing plate. In order to obtain an optical film with reduced occurrence of cracks and chips when punching a polarizing plate, silica particles having a specific degree of hydrophobicity are contained.

  The silica particles according to the present invention have a degree of hydrophobicity measured by a methanol wettability method of 20% or less when the first solution having a volume ratio of methanol and pure water of 3: 7 is used. And silica particles having a hydrophobicity of 80% or more when a second solution of methanol and pure water having a volume ratio of 6: 4 is used. The degree of hydrophobicity is measured by the MW method described above.

  Silica particles are particles containing silicon dioxide as a main component. The main component means that it contains 50% or more of the components constituting the particles, preferably 70% or more, more preferably 80% or more, and particularly preferably 90% or more.

  Further, it is preferable to add fine particles which are silicon dioxide particles and whose surface is subjected to a hydrophobic treatment by an alkylation treatment, since the dispersibility in a solvent is good and the generation of foreign substances can be suppressed.

  It is preferable that the above-mentioned hydrophobic treatment for the silica particles is an alkylation treatment. The surface of the alkylated fine particles has an alkyl group, and the alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably, It is in the range of 1-8 carbon atoms.

  The silica particles having an alkyl group having 1 to 20 carbon atoms on the surface can be obtained, for example, by treating the silicon dioxide particles with octylsilane. Further, as an example having an octyl group on the surface, it is commercially available under the trade name of Aerosil R805 (manufactured by Nippon Aerosil Co., Ltd.) and is preferably used.

  The average primary particle size of the silica particles is preferably in the range of 5 to 400 nm, and more preferably in the range of 10 to 300 nm.

  The average particle size of the secondary particles of the silica particles is preferably in the range of 100 to 400 nm, and if the average particle size of the primary particles is in the range of 100 to 400 nm, it is included as a primary particle without aggregation. It is also preferred that the

<Measurement method of average particle size of silica particles>
The measurement of the particle diameter of the silica particles in the optical film is performed by taking a cross section of the film cut by a microtome at an appropriate magnification with a scanning electron microscope (SEM), and measuring 100 particles included in the tomographic cut photograph. Is measured, and the average value is determined to be the average particle size. When the cross section of the particle is circular, the particle diameter is defined as the diameter. When the particle is not circular, the area is calculated, and the diameter is calculated as a circle.

SEM: JSM-6060LA (JEOL: JEOL Ltd.)
Microtome: Leica EM UC6
The content of the silica particles in the film must be 0.1 to 2.5% by mass based on the total mass of the film, and is preferably in the range of 0.5 to 2.0% by mass, In particular, it is preferable to be within the range of 1.0 to 2.0% by mass in order to exhibit the effects of the present invention.

  As the silica particles, commercially available products can be preferably used. In addition to the above-mentioned Aerosil R805, for example, Aerosil R972, R972V, R974, R976S, R812, R812S, RY300, 300, R202, OX50, TT600 (above, Nippon Aerosil Co., Ltd.) The product is commercially available under the trade name of the company) and can be used.

  Among these, Aerosil R805, R812, and R976S are preferable because they satisfy the degree of hydrophobicity according to the present invention, so that the handleability during handling can be improved and the haze of the optical film can be kept low.

  The optical film of the present invention preferably contains silica particles and has a dynamic friction coefficient of at least one surface in the range of 0.2 to 1.0. The dynamic friction coefficient can be measured according to “JIS K7125 Plastic-film and sheet friction coefficient test method”.

  Examples of the method for adding the silica particles according to the present invention include the following first to third methods, and any method may be used.

[First addition method]
After stirring and mixing the solvent and the particles, dispersion is performed using a disperser, and this is added to the dope and stirred to obtain a casting dope.

[Second addition method]
After stirring and mixing the solvent and the particles, the particles are dispersed using a disperser to prepare a particle dispersion. Next, a small amount of resin is added to a solvent, and the above-mentioned particle dispersion is added to a solution obtained by stirring and dissolving, and then the resultant is added to a raw material dope solution and mixed well to obtain a casting dope.

[Third addition method]
After adding a small amount of resin to the solvent and dissolving with stirring, the particles are added and dispersed using a disperser. This is added to the dope and mixed well.

  When a recycled film is used for preparing the dope, the silica particles contained in the completed casting dope may be those contained therein. The rolled dope is preferably according to the invention.

[3] Hindered phenolic compound The phenolic compound is a known compound and is described in, for example, columns 12 to 14 of US Pat. No. 4,839,405, and includes a 2,6-dialkylphenol derivative compound. . As a preferable compound among such compounds, a compound represented by the following general formula (A) is preferable.

In the formula, R _{51 to} R ₅₆ represent a hydrogen atom or a substituent. Examples of the substituent include a halogen atom (eg, a fluorine atom, a chlorine atom, etc.), an alkyl group (eg, a methyl group, an ethyl group, an isopropyl group, a hydroxyethyl group, a methoxymethyl group, a trifluoromethyl group, a t-butyl group, etc.) ), A cycloalkyl group (eg, cyclopentyl group, cyclohexyl group, etc.), an aralkyl group (eg, benzyl group, 2-phenethyl group, etc.), an aryl group (eg, phenyl group, naphthyl group, p-tolyl group, p-chlorophenyl) Group), an alkoxy group (eg, a methoxy group, an ethoxy group, an isopropoxy group, a butoxy group, etc.), an aryloxy group (eg, a phenoxy group, etc.), a cyano group, an acylamino group (eg, an acetylamino group, a propionylamino group) Etc.), alkylthio groups (eg, methylthio group, ethylthio group, butylthio group) Group), an arylthio group (eg, a phenylthio group), a sulfonylamino group (eg, a methanesulfonylamino group, a benzenesulfonylamino group, etc.), a ureido group (eg, a 3-methylureido group, a 3,3-dimethylureido group) , 1,3-dimethylureido group, etc.), sulfamoylamino group (dimethylsulfamoylamino group, etc.), carbamoyl group (eg, methylcarbamoyl group, ethylcarbamoyl group, dimethylcarbamoyl group, etc.), sulfamoyl group (eg, Ethylsulfamoyl group, dimethylsulfamoyl group, etc.), alkoxycarbonyl group (eg, methoxycarbonyl group, ethoxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenoxycarbonyl group, etc.), sulfonyl group (eg, methanesulfonyl) Group Sulfonyl group, phenylsulfonyl group, etc.), acyl group (eg, acetyl group, propanoyl group, butyroyl group, etc.), amino group (methylamino group, ethylamino group, dimethylamino group, etc.), cyano group, hydroxy group, nitro group Group, nitroso group, amine oxide group (for example, pyridine-oxide group), imide group (for example, phthalimide group), disulfide group (for example, benzene disulfide group, benzothiazolyl-2-disulfide group, etc.), carboxyl group, sulfo group And heterocyclic groups (eg, pyrrole group, pyrrolidyl group, pyrazolyl group, imidazolyl group, pyridyl group, benzimidazolyl group, benzothiazolyl group, benzoxazolyl group, etc.). These substituents may be further substituted.

Further, a phenol compound in which R ₅₁ is a hydrogen atom and R ₅₂ and R ₅₆ are t-butyl groups is preferable.

  Although the hindered phenol compound according to the present invention is not particularly limited, the following specific examples can be given.

  Specific examples of the compound include n-octadecyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate, n-octadecyl 3- (3,5-di-t-butyl-4-). (Hydroxyphenyl) -acetate, n-octadecyl 3,5-di-t-butyl-4-hydroxybenzoate, n-hexyl 3,5-di-t-butyl-4-hydroxyphenylbenzoate, n-dodecyl 3,5- Di-t-butyl-4-hydroxyphenylbenzoate, neo-dodecyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, dodecyl β (3,5-di-t-butyl-4- (Hydroxyphenyl) propionate, ethyl α- (4-hydroxy-3,5-di-t-butylphenyl) isobutyrate, octadecyl α- (4 Hydroxy-3,5-di-t-butylphenyl) isobutyrate, octadecyl α- (4-hydroxy-3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2- (n-octylthio) ethyl 3, 5-di-t-butyl-4-hydroxy-benzoate, 2- (n-octylthio) ethyl 3,5-di-t-butyl-4-hydroxy-phenylacetate, 2- (n-octadecylthio) ethyl 3, 5-di-t-butyl-4-hydroxyphenyl acetate, 2- (n-octadecylthio) ethyl 3,5-di-t-butyl-4-hydroxy-benzoate, 2- (2-hydroxyethylthio) ethyl 3 , 5-Di-tert-butyl-4-hydroxybenzoate, diethyl glycol bis- (3,5-di-tert-butyl-4-hydroxy -Phenyl) propionate, 2- (n-octadecylthio) ethyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, stearamide N, N-bis- [ethylene 3- (3,5- Di-tert-butyl-4-hydroxyphenyl) propionate], n-butylimino N, N-bis- [ethylene 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2- (2 -Stearoyloxyethylthio) ethyl 3,5-di-t-butyl-4-hydroxybenzoate, 2- (2-stearoyloxyethylthio) ethyl 7- (3-methyl-5-t-butyl-4-hydroxyphenyl ) Heptanoate, 1,2-propylene glycol bis- [3- (3,5-di-t-butyl-4-hydroxyphenyl) pro Onate], ethylene glycol bis- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], neopentyl glycol bis- [3- (3,5-di-t-butyl-4- Hydroxyphenyl) propionate], ethylene glycol bis- (3,5-di-t-butyl-4-hydroxyphenylacetate), glycerin-1-n-octadecanoate-2,3-bis- (3,5- Di-tert-butyl-4-hydroxyphenyl acetate), pentaerythritol-tetrakis- [3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate], 1,1,1-triene Methylolethane-tris- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], sorbitol hexa- 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2-hydroxyethyl 7- (3-methyl-5-tbutyl-4-hydroxyphenyl) propionate, 2-stearoyloxyethyl 7 -(3-Methyl-5-tert-butyl-4-hydroxyphenyl) heptanoate, 1,6-n-hexanediol-bis [(3 ', 5'-di-tert-butyl-4-hydroxyphenyl) propionate] Pentaerythritol-tetrakis (3,5-di-t-butyl-4-hydroxyhydrocinnamate) and the like.

  Above all, the following exemplified compounds are shown as specific examples of useful hindered phenolic antioxidants, but are not limited thereto.

  Further, phenol compounds of the above type are commercially available, for example, from BASF Japan Ltd. under the trade names “Irganox1035”, “Irganox1076” and “Irganox1010”.

  The addition amount of the phenolic compound to 100 parts by mass of the cycloolefin-based resin can be appropriately designed, but is preferably in the range of 0.1 to 1.0 part by mass, and more preferably in the range of 0.3 to 0.5 part by mass. More preferably, there is.

[4] Other additives [4.1] Plasticizer A plasticizer is, for example, a polyester compound, a polyhydric alcohol ester compound, a polycarboxylic acid ester compound (including a phthalate ester compound), Glycolate compounds and ester compounds (including fatty acid ester compounds and phosphate ester compounds) are included. These may be used alone or in combination of two or more.

  A preferred plasticizer for the optical film of the present invention is a polyester compound containing a repeating unit obtained by reacting a dicarboxylic acid and a diol.

  The dicarboxylic acid constituting the polyester compound is an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid, and is preferably an aromatic dicarboxylic acid. The dicarboxylic acid may be one type or a mixture of two or more types.

  The diol constituting the polyester compound is an aromatic diol, an aliphatic diol or an alicyclic diol, preferably an aliphatic diol, and more preferably a diol having 1 to 4 carbon atoms. The diol may be one kind or a mixture of two or more kinds.

  Among them, the polyester compound preferably contains a repeating unit obtained by reacting a dicarboxylic acid containing at least an aromatic dicarboxylic acid and a diol having 1 to 4 carbon atoms, and the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid It is more preferable to include a repeating unit obtained by reacting a dicarboxylic acid containing the compound with a diol having 1 to 4 carbon atoms.

  Both ends of the molecule of the polyester compound may or may not be sealed, but are preferably sealed from the viewpoint of reducing the moisture permeability of the film.

  Further, the polyhydric alcohol ester compound is an ester compound (alcohol ester) of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and is preferably a divalent to 20-valent aliphatic polyhydric alcohol ester. The polyhydric alcohol ester compound preferably has an aromatic ring or a cycloalkyl ring in the molecule.

  Preferred examples of the aliphatic polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2- Butanediol, 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, trimethylolpropane , Pentaerythritol, trimethylolethane, xylitol and the like. Among them, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, xylitol and the like are preferable.

  The monocarboxylic acid is not particularly limited, and may be an aliphatic monocarboxylic acid, an alicyclic monocarboxylic acid, an aromatic monocarboxylic acid, or the like. An alicyclic monocarboxylic acid or an aromatic monocarboxylic acid is preferred in order to increase the moisture permeability of the film and make it less likely to volatilize. The monocarboxylic acid may be one kind or a mixture of two or more kinds. Further, all of the OH groups contained in the aliphatic polyhydric alcohol may be esterified, or some of them may be left as OH groups.

  The aliphatic monocarboxylic acid is preferably a fatty acid having 1 to 32 carbon atoms and having a straight or side chain. The carbon number of the aliphatic monocarboxylic acid is more preferably 1 to 20, and further preferably 1 to 10. Examples of aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanoic acid, undecylic acid, lauric acid, and tridecylic acid. , Myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachiic acid, behenic acid, lignoceric acid, serotinic acid, heptacosanoic acid, montanic acid, melicic acid, saturated fatty acids such as lacseric acid; undecylenic acid, Unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid, and arachidonic acid are included. Above all, acetic acid or a mixture of acetic acid and another monocarboxylic acid is preferable in order to increase the compatibility with cellulose acetate.

  Examples of alicyclic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and the like.

  Examples of the aromatic monocarboxylic acid include benzoic acid; one in which 1 to 3 alkyl groups or alkoxy groups (for example, methoxy group or ethoxy group) are introduced into a benzene ring of benzoic acid (for example, toluic acid and the like); Aromatic monocarboxylic acids having two or more benzene rings (eg, biphenylcarboxylic acid, naphthalenecarboxylic acid, tetralincarboxylic acid, etc.) are included, and benzoic acid is preferable.

  Specific examples of the polyhydric alcohol ester compound include compounds described in paragraphs [0058] to [0061] of JP-A-2006-113239.

  The polycarboxylic acid ester compound is an ester compound of a polyvalent carboxylic acid having a valency of 2 or more, preferably 2 to 20 and an alcohol compound. The polycarboxylic acid is preferably a divalent to divalent aliphatic polycarboxylic acid, or a trivalent to divalent aromatic polycarboxylic acid or a trivalent to divalent alicyclic polycarboxylic acid. .

  Examples of polycarboxylic acid ester compounds include triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyl triphenyl citrate, and acetyl tribenzyl citrate. Rates, dibutyl tartrate, diacetyl dibutyl tartrate, tributyl trimellitate, tetrabutyl pyromellitate, and the like.

  Examples of glycolate compounds include alkyl phthalyl alkyl glycolates. Examples of alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl Ethyl glycolate, ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl Glycolate, butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octyl phthalyl methyl glycolate, octyl phthalyl ethyl Glycolate and the like, preferably ethyl phthalyl ethyl glycolate.

  The ester compound includes a fatty acid ester compound, a citrate ester compound, a phosphate ester compound, and the like.

  Examples of the fatty acid ester compound include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate and the like. Examples of the citrate compound include acetyltrimethyl citrate, acetyltriethyl citrate, acetyltributyl citrate, and the like. Examples of phosphate ester compounds include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, biphenyl diphenyl phosphate, trioctyl phosphate, tributyl phosphate, and the like, preferably triphenyl phosphate. .

  Among them, a polyester compound, a glycolate compound and a phosphate compound are preferred, and a polyester compound is particularly preferred.

  The content of the plasticizer is preferably in the range of 1 to 20% by mass, and more preferably in the range of 1.5 to 15% by mass, based on 100 parts by mass of the cycloolefin-based resin. When the content of the plasticizer is within the above range, the effect of imparting plasticity can be exhibited, and the exudation resistance of the plasticizer from the optical film is excellent.

[4.2] Retardation Raising Agent The optical film of the present invention can contain a retardation raising agent for adjusting the retardation.

  The retardation increasing agent referred to in the present application refers to a retardation value Rt (measured at a light wavelength of 590 nm) in a thickness direction of an optical film containing 3 parts by mass of the compound with respect to 100 parts by mass of a cycloolefin-based resin. A compound having a function of exhibiting a value of 1.1 times or more as compared with an optical film.

  The retardation increasing agent used in the present invention is not particularly limited, and has, for example, an aromatic ring described in JP-A-2006-113239, paragraphs [0143] to [0179], which are conventionally known. Discotic compounds (1,3,5-triazine-based compounds and the like), rod-shaped compounds described in paragraphs [0106] to [0112] of JP-A-2006-113239, paragraphs [0118] to [0133] of JP-A-2012-214682 And the like.

[4.3] Ultraviolet Absorber The optical film of the present invention preferably contains an ultraviolet absorber in order to block unnecessary ultraviolet rays emitted to the polarizing plate and the liquid crystal display device.

  Examples of the ultraviolet absorber include, for example, oxybenzophenone-based compounds, benzotriazole-based compounds, salicylic acid ester-based compounds, benzophenone-based compounds, cyanoacrylate-based compounds, nickel complex salt-based compounds, and the like. Compounds are preferred. Further, ultraviolet absorbers described in JP-A-10-182621 and JP-A-8-337574, and polymer ultraviolet absorbers described in JP-A-6-148430 are also preferably used.

  When the optical film of the present invention is used as a protective film for a polarizing plate in addition to the optical compensation film, the ultraviolet absorber is excellent in the ability to absorb ultraviolet light having a wavelength of 370 nm or less from the viewpoint of preventing deterioration of the polarizer and liquid crystal. In addition, from the viewpoint of the display properties of the liquid crystal, it is preferable that the liquid crystal display has characteristics that absorb less visible light having a wavelength of 400 nm or more.

  The amount of the ultraviolet absorber added is preferably in the range of 0.1 to 5.0% by mass, more preferably in the range of 0.5 to 5.0% by mass, based on the polymer composition. preferable.

  Examples of the benzotriazole-based ultraviolet absorber useful in the present invention include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole and 2- (2'-hydroxy-3 ', 5'-di-t. -Butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-butyl Phenyl) -5-chlorobenzotriazole, 2- [2'-hydroxy-3 '-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2,2 -Methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- (2'-hydroxy-3 -T-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol, 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, but is not limited thereto.

  As commercial products, “Tinuvin (TINUVIN) 109”, “Tinuvin (TINUVIN) 171”, “Tinuvin (TINUVIN) 326”, and “Tinuvin (TINUVIN) 328” (all trade names, manufactured by BASF Japan) are preferable. Can be used.

[5] Method for Producing Optical Film The method for producing an optical film of the present invention can employ a solution casting film forming method or a melt casting film forming method. preferable.

  The optical film of the present invention is formed by a solution casting method, and has a cycloolefin-based resin having at least one hydrogen bond-accepting group, silica particles satisfying the degree of hydrophobicity, and the hindered phenol-based resin. It is preferable to prepare a dope containing a compound and an organic solvent including an alcohol-based solvent at a dissolution temperature of 15 to 50 ° C.

  When the dissolution temperature is 15 ° C. or higher, the resin and additives can be sufficiently dissolved, so that a film with less foreign matter can be obtained. In addition, when the temperature is 50 ° C. or less, the effect of suppressing coloring by adding silica particles having a good affinity with alcohol is preferable from the viewpoint that the doping due to the reaction of the alcohol and the hindered phenol compound and the coloring of the obtained film can be suppressed. There is.

  The optical film of the present invention comprises a step of preparing a dope containing at least a cycloolefin-based resin, silica particles, an organic solvent containing a hindered phenol compound and an alcohol-based solvent (dope preparation step), Forming a web (also referred to as a casting film) by casting into a web (casting step), evaporating a solvent from the web on a support (solvent evaporation step), and separating the web from the support (Peeling step), a step of drying the obtained film (preliminary drying step), a step of stretching the film (stretching step), a step of further drying the stretched film (drying step), and winding the obtained optical film. It is preferably manufactured by a taking step (winding step).

  The above steps will be described with reference to the drawings.

  FIG. 1 is a diagram schematically illustrating an example of a dope preparation step, a casting step, a drying step, and a winding step of a solution casting film forming method preferred for the present invention.

  The fine particle dispersion in which the solvent and the silica particles according to the present invention are dispersed by the disperser passes from the charging tank 41 through the filter 44 and is stored in the stock tank 42. On the other hand, the cycloolefin-based resin as the main dope is dissolved in the dissolving tank 1 together with the solvent, and the fine particle dispersion stored in the stock pot 42 is appropriately added and mixed to form the main dope. The obtained main dope is filtered from the filter 3 and the stock pot 4 by the filter 6, the additive is added by the merging pipe 20, mixed by the mixer 21, and sent to the pressure die 30.

  On the other hand, additives (such as the hindered phenolic compound according to the present invention, an ultraviolet absorber, and a phase difference increasing agent) are dissolved in a solvent, pass through the filter 12 from the additive preparation tank 10 and into the stock tank 13. Be stocked. Thereafter, the mixture is mixed with the main dope by the confluent pipe 20 and the mixer 21 via the conduit 16 through the filter 15.

  The main dope fed to the pressure die 30 is cast on a metal belt-shaped support 31 to form a web 32, and is peeled off at a peeling position 33 after predetermined drying to obtain a film. The peeled web 32 is dried to a predetermined residual solvent amount while passing through a number of transport rollers, and then stretched in the longitudinal direction or the width direction by the stretching device 34. After the stretching, the film is dried by passing it through the transport roller 36 until it reaches a predetermined residual solvent amount by the drying device 35, and is wound into a roll by the winding device 37.

  Hereinafter, each step will be described.

(1) Dope preparation step In a dissolving vessel, an organic solvent mainly containing a good solvent for the cycloolefin resin, and the cycloolefin resin and the hindered phenol compound, optionally, a retardation increasing agent, silica particles or other. A step of preparing a dope by dissolving the compound with stirring, or mixing the hindered phenol compound, the phase difference enhancer, silica particles or other compound solution with the cycloolefin-based resin solution, and mainly dissolving the compound. This is a step of preparing a dope as a liquid.

  When the optical film of the present invention is produced by a solution casting method, an organic solvent useful for forming a dope includes a cycloolefin-based resin, a hindered phenol-based compound, or a phase difference enhancer and other compounds simultaneously dissolved therein. It is preferable that

  The following solvents are preferably used as the organic solvent used.

  Solvents used in the solution casting method include, for example, chlorinated solvents such as chloroform and dichloromethane; aromatic solvents such as toluene, xylene, benzene, and a mixed solvent thereof; methanol, ethanol, isopropanol, n-butanol, Alcohol solvents such as 2-butanol; and methyl cellosolve, ethyl cellosolve, butyl cellosolve, dimethylformamide, dimethylsulfoxide, dioxane, cyclohexanone, tetrahydrofuran, acetone, methyl ethyl ketone (MEK), ethyl acetate, diethyl ether, and the like. These solvents may be used alone or in combination of two or more.

  When the solvent according to the present invention is a mixed solvent of a good solvent and a poor solvent, the good solvent is, for example, dichloromethane as a chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate as a non-chlorinated organic solvent. , Acetone, methyl ethyl ketone, tetrahydrofuran, 1,3-dioxolan, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-Difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol , 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, methanol, ethanol, n-propanol, is - propanol, n- butanol, sec- butanol, tert- butanol and the like, is preferably Among them, dichloromethane.

  The poor solvent is the alcohol solvent according to the present invention, and it is necessary that the poor solvent be contained in the optical film in an amount of 10 to 1000 ppm in order to exert the effects of the present invention.

  The content of the alcohol-based solvent contained in the optical film of the present invention is a so-called residual solvent amount, and refers to the content contained in the film after the film is produced. The amount of the solvent can be quantified by head space gas chromatography, which will be described later, and the measurement refers to a value measured during a period from the film production to before the film processing. Usually, the film is wrapped in a protective sheet or the like after being manufactured and wound up, stored in a semi-closed state, and remains in that state until processed, so that the amount of residual solvent varies little. Therefore, it is possible to determine whether or not the configuration of the present invention is based on the value of the residual solvent amount measured during the period from the film production to before the film processing.

  The amount of the residual solvent can be controlled by controlling the composition ratio of the solvent, drying conditions such as drying temperature and drying time during film formation, and film thickness.

  The content of the alcohol-based solvent contained in the optical film of the present invention is preferably in the range of 10 to 500 ppm, and more preferably in the range of 20 to 200 ppm. When the content is 10 ppm or more, the effect of the present invention is exhibited, and the releasability from the metal support in the solution casting film is also improved. If it is 1000 ppm or less, it is preferable from the viewpoint of haze and environmental safety.

  The alcoholic solvent according to the present invention is preferably selected from methanol, ethanol and butanol from the viewpoint of improving the peelability and enabling high-speed casting, together with the effects of the present invention. Among them, ethanol is preferred from the above viewpoint.

  In the present invention, if it is a mixed solvent, the good solvent is preferably used in an amount of 55% by mass or more based on the total amount of the solvent, more preferably 70% by mass or more, and further preferably 80% by mass or more.

Further, the optical film of the present invention is more preferably used in combination with an alcohol-based solvent having a hydroxy group and water from the viewpoint of improving productivity. It contained in the film in the range of 500 ppm.

  Since water has a plurality of hydrogen bonding donor groups in one molecule, water can be preferably used to increase the strength of the film. It is preferable that water contains 0.1 to 1% by mass based on the total amount of the solvent. When the content is 0.1% by mass or more, it is easy to interact with another alcohol-based solvent or a cycloolefin-based resin or a silica particle containing a hydrogen bond-accepting group. Gelling of the strong cycloolefin-based resin can be suppressed, and generation of foreign matter can be suppressed.

<Amount of residual solvent>
The residual amount of the alcohol and water used as the solvent component is measured by the following measurement method.

  The optical film cut into a certain shape was placed in a 20 mL closed glass container, and treated at 120 ° C. for 20 minutes, followed by gas chromatography (equipment: HP 5890SERIES II, column: J & W DB-WAX (0.32 mm inner diameter, The length was measured at a temperature of 40 ° C. for 5 minutes, and then the temperature was raised to 100 ° C. at 80 ° C./min.

  For dissolving the cycloolefin resin and the hindered phenolic compound, and in some cases, the retardation increasing agent and other compounds, a method of dissolving at ordinary pressure, a method of dissolving at a temperature lower than the boiling point of the main solvent, and a method of pressurizing at a temperature higher than the boiling point of the main solvent. A cooling and melting method as described in JP-A-9-95544, JP-A-9-95557, or JP-A-9-95538, and a method described in JP-A-11-21379. Although various dissolving methods such as a method of performing at a high pressure can be used, it is preferable to perform the dissolving in the range of 0.8 to 4 MPa from the viewpoint of solubility.

  The concentration of the cycloolefin-based resin in the dope is preferably in the range of 10 to 40% by mass. The compound is added to the dope during or after dissolution to dissolve and disperse, and then filtered with a filter medium, defoamed, and sent to the next step by a liquid sending pump.

  Regarding the filtration of the dope, preferably, the dope is filtered with a filter medium having a 90% trapping particle diameter of 10 to 100 times the average particle diameter of the fine particles, preferably in the main filter 3 having a leaf disk filter. preferable.

  In the present invention, the filter medium used for filtration preferably has a small absolute filtration precision, but if the absolute filtration precision is too small, clogging of the filter medium is likely to occur, and the filter medium must be replaced frequently. However, there is a problem that productivity is reduced.

  Therefore, in the present invention, the filter medium used for the cycloolefin-based resin-containing dope preferably has an absolute filtration accuracy of 0.008 mm or less, more preferably 0.001 to 0.008 mm, and more preferably 0.003 to 0. Filter media in the range of 0.006 mm are more preferred.

  There is no particular limitation on the material of the filter medium, and ordinary filter mediums can be used. However, the filter medium made of plastic fiber such as polypropylene or Teflon (registered trademark) or the metal filter medium such as stainless steel fiber may fall off the fiber. Is preferred because there is no

In the present invention, the flow rate of the dope during ^{filtration, 10~80kg / (h · m 2} ), it is preferable preferably is ^{20~60kg / (h · m 2)} . Here, if the flow rate of the dope at the time of filtration is 10 kg / (h · m ² ) or more, efficient productivity is obtained, and the flow rate of the dope at the time of filtration is within 80 kg / (h · m ² ). In this case, the pressure applied to the filter medium is appropriate, and the filter medium is not damaged, which is preferable.

  The filtration pressure is preferably 3500 kPa or less, more preferably 3000 kPa or less, even more preferably 2500 kPa or less. The filtration pressure can be controlled by appropriately selecting the filtration flow rate and the filtration area.

  In many cases, the main dope may contain about 10 to 50% by mass of a return material.

  Returned material is, for example, an optical film that is finely pulverized, which is generated when an optical film is formed, a material that has been cut off on both sides of the film, or an optical film that exceeds the specified value of the film due to abrasion or the like. The web is used.

  As a raw material of the resin used for preparing the dope, a material obtained by pelletizing a cycloolefin-based resin and other compounds in advance can also be preferably used.

(2) Casting Step (2.1) Casting of Dope An endless metal support 31, which sends a dope to a pressurizing die 30 through a liquid sending pump (for example, a pressurized metering gear pump) and transfers it endlessly, For example, a step of casting a dope from a pressing die slit to a casting position on a metal support such as a stainless steel belt or a rotating metal drum.

  The metal support in the casting step is preferably one whose surface is mirror-finished. As the metal support, a stainless steel belt or a drum whose surface is plated with a casting is preferably used. The width of the cast can be in the range of 1-4 m, preferably in the range of 1.3-3 m, more preferably in the range of 1.5-2.8 m. The surface temperature of the metal support in the casting step is set at -50 ° C to a temperature not higher than the temperature at which the solvent does not boil and foam, more preferably at -30 to 0 ° C. A higher temperature is preferred because the drying speed of the web (the dope is cast on a casting metal support and the formed dope film is called a web) can be increased. However, if the temperature is too high, the web may foam. In some cases, the flatness may deteriorate. The preferable temperature of the support is appropriately determined at 0 to 100 ° C, and more preferably at 5 to 30 ° C. Alternatively, it is also a preferable method to gel the web by cooling and to peel the web from the drum while containing a large amount of residual solvent.

  The method of controlling the temperature of the metal support is not particularly limited, and there are a method of blowing hot or cold air, and a method of bringing hot water into contact with the back side of the metal support. It is preferable to use hot water since the time required for the temperature of the metal support to become constant is short because heat is transferred more efficiently. When using hot air, in consideration of the temperature drop of the web due to the latent heat of evaporation of the solvent, while using hot air at the boiling point of the solvent or higher, air with a higher temperature than the target temperature may be used while preventing foaming. . In particular, it is preferable to change the temperature of the support and the temperature of the drying air during the period from the casting to the peeling to efficiently perform the drying.

  The die is preferably a pressure die which can adjust the slit shape of the die portion of the die and can easily make the film thickness uniform. Examples of the pressure die include a coat hanger die and a T die, all of which are preferably used. The surface of the metal support is a mirror surface. In order to increase the film formation speed, two or more pressure dies may be provided on the metal support, and the doping amounts may be divided and stacked.

(2.2) Solvent Evaporation Step This is a step of heating the web on the casting metal support to evaporate the solvent, and is a step of controlling the amount of residual solvent at the time of peeling described later.

  To evaporate the solvent, there are a method of blowing air from the web side, a method of transferring heat with liquid from the back of the support, a method of transferring heat from the front and back by radiant heat, and the like. Is preferred. Further, a method of combining them is also preferably used. The web on the support after casting is preferably dried on the support in an atmosphere of 30 to 100 ° C. In order to maintain the temperature in an atmosphere of 30 to 100 ° C., it is preferable to apply hot air at this temperature to the upper surface of the web or to heat the web by means such as infrared rays.

  From the viewpoint of surface quality, moisture permeability, and releasability, the web is preferably released from the support within 30 to 180 seconds.

(2.3) Peeling Step This is a step of peeling the web from which the solvent has evaporated on the metal support at the peeling position. The peeled web is sent to the next step as a film.

  The temperature at the peeling position on the metal support is preferably in the range of 10 to 40C, more preferably in the range of 11 to 30C.

  In the present invention, the solvent in the web is evaporated in the solvent evaporation step, but the residual solvent amount of the web on the metal support at the time of peeling is preferably in the range of 15 to 100% by mass. It is preferable to control the amount of the residual solvent by controlling the drying temperature and the drying time in the solvent evaporation step.

  When the amount of the residual solvent is 15% by mass or more, the silica particles have a distribution in the thickness direction and are uniformly dispersed in the film during the drying process on the support, which is preferable.

  Further, when the amount of the residual solvent is within 100% by mass, the film has self-supporting properties, can prevent poor peeling of the film, and can maintain the mechanical strength of the web, so that the flatness at the time of peeling is improved. It is possible to suppress the occurrence of rubbing and vertical stripes due to the peeling tension.

  The residual solvent amount of the web or film is defined by the following formula (Z).

Formula (Z)
Residual solvent amount (%) = (mass before heat treatment of web or film−mass after heat treatment of web or film) / (mass after heat treatment of web or film) × 100
Note that the heat treatment at the time of measuring the amount of the residual solvent means performing heat treatment at 115 ° C. for one hour.

  The peeling tension when peeling the web from the metal support to form a film is usually in the range of 196 to 245 N / m. However, when wrinkles are likely to occur during peeling, the peeling is performed at a tension of 190 N / m or less. Is preferred.

  In the present invention, the temperature at the peeling position on the metal support is preferably in the range of −50 to 40 ° C., more preferably in the range of 10 to 40 ° C., and in the range of 15 to 30 ° C. Is most preferred.

(3) Drying and Stretching Step The drying step can be performed by dividing into a preliminary drying step and a main drying step.

(3.1) Preliminary drying step The film obtained by peeling the web from the metal support is preliminarily dried. For preliminary drying of the film, the film may be dried while being conveyed by a number of rollers arranged vertically, or may be dried while being conveyed while fixing both ends of the film with clips like a tenter dryer. Good.

  The means for drying the web is not particularly limited, and can be generally performed by hot air, infrared rays, a heating roller, a microwave, or the like, but is preferably performed by hot air in terms of simplicity.

  The drying temperature in the predrying step of the web is preferably the glass transition point of the film −5 ° C. or less, and it is effective to perform the heat treatment at a temperature of 30 ° C. or more for 1 minute to 30 minutes. The drying is performed at a drying temperature in the range of 40 to 150 ° C, more preferably in the range of 50 to 100 ° C.

(3.2) Stretching Step The optical film of the present invention is subjected to a stretching treatment in a stretching device 34 in the amount of residual solvent to uniformly disperse silica particles in a resin in the film or to improve the flatness of the film. Desired retardation values Ro and Rt can be obtained by improving or controlling the orientation of molecules in the film.

  In the method for producing an optical film of the present invention, in the step of stretching the film, the amount of residual solvent at the start of stretching is preferably 1% by mass or more and less than 15% by mass. More preferably, it is in the range of 2 to 10% by mass, and when it is in the range of the amount of the residual solvent, it is possible to avoid applying uneven stress to the film during stretching.

  The optical film of the present invention is preferably stretched in the longitudinal direction (also referred to as the MD direction or the casting direction) and / or the width direction (also referred to as the TD direction) and / or in an oblique direction, and at least by a stretching device. It is preferable to manufacture by stretching in the width direction.

  The stretching operation may be performed in multiple stages. When performing biaxial stretching, simultaneous biaxial stretching may be performed or stepwise may be performed. In this case, stepwise means, for example, that stretching in different stretching directions can be performed sequentially, or that stretching in the same direction is divided into multiple stages, and stretching in different directions is added to any of the stages. Is also possible.

Thus, for example, the following stretching steps are also possible:
・ Stretch in the longitudinal direction → stretch in the width direction → stretch in the longitudinal direction → stretch in the longitudinal direction ・ Stretch in the transverse direction → stretch in the transverse direction → stretch in the longitudinal direction → stretch in the longitudinal direction ・ Stretch in the transverse direction → Stretching in an oblique direction Simultaneous biaxial stretching also includes a case where the film is stretched in one direction and the other is contracted by relaxing the tension.

  When the glass transition temperature of the optical film of the present invention is Tg in the longitudinal direction and / or the width direction such that the film thickness after stretching is in a desired range, preferably in the width direction, It is preferable to stretch in a temperature range of (Tg + 5) to (Tg + 50) ° C. When the film is stretched in the above temperature range, the phase difference can be easily adjusted and the stretching stress can be reduced, so that the haze is reduced. Further, the occurrence of breakage is suppressed, and an optical film having excellent flatness and coloring properties of the film itself can be obtained. The stretching temperature is preferably in the range of (Tg + 10) to (Tg + 40) ° C.

  The glass transition temperature Tg as used herein is a midpoint glass transition temperature (Tmg) measured using a commercially available differential scanning calorimeter at a heating rate of 20 ° C./min and determined according to JIS K7121 (1987). It is. A specific method of measuring the glass transition temperature Tg of the optical film is measured using a differential scanning calorimeter DSC220 manufactured by Seiko Instruments Inc. according to JIS K7121 (1987).

  The optical film of the present invention preferably stretches the film at least in the width direction at a stretch ratio in the range of 5 to 40% with respect to the original width. It is more preferred that the film be stretched at a stretching ratio in the range of ４０40%. In particular, the stretching ratio is more preferably stretched within the range of 10 to 30% with respect to the original width. Within the above range, not only a desired retardation value can be obtained but also a film can be made thinner, particularly when a retardation increasing agent is contained. The stretching ratio in the present invention refers to the ratio (%) of the length of the film after stretching to the length or width of the film before stretching.

  The method of stretching in the longitudinal direction is not particularly limited. For example, a method in which a circumferential speed difference is applied to a plurality of rolls, and a longitudinal stretching is performed using the circumferential speed difference between the rolls, and both ends of the web are fixed with clips or pins, and the intervals between the clips and pins are widened in the traveling direction. And a method of stretching in the vertical and horizontal directions simultaneously and stretching in both the vertical and horizontal directions. Of course, these methods may be used in combination.

  In order to stretch in the width direction, for example, as shown in JP-A-62-46625, the entire width of the web is held at both ends by clips or pins in the width direction or a part of the drying process. A method of drying while drying (referred to as a tenter method), in particular, a tenter method using a clip and a pin tenter method using a pin are preferably used.

  In stretching in the width direction, it is preferable to stretch the film in the width direction at a stretching speed of 250 to 500% / min from the viewpoint of improving the flatness of the film.

  When the stretching speed is 250% / min or more, the flatness is improved, and the film can be processed at a high speed. Therefore, it is preferable from the viewpoint of production suitability. It can be processed without any problem, which is preferable.

  The preferred stretching speed is in the range of 300 to 400% / min, which is effective at the time of stretching at a low magnification. The stretching speed is defined by the following formula 1.

Formula 1 Stretching speed (% / min) = [(d ₁ / d ₂ ) −1] × 100 (%) / t
(In Formula 1, d ₁ is the width in the stretching direction of the optical film of the present invention after stretching, d ₂ is the width in the stretching direction of the optical film before stretching, and t is the time required for stretching. (Min).
The optical film of the present invention can be provided with a desired retardation value by stretching.

  The film thickness of the optical film of the present invention is 5 μm ≦ d ≦ 40 μm, and the in-plane phase difference Ro and the thickness direction phase difference Rt at the measurement wavelength of 590 nm are Ro ≦ 5 nm and −15 nm ≦ Rt ≦ 15 nm, respectively. When it is used as a polarizing plate protective film, it is preferable from the viewpoint that a light and thin polarizing plate can be provided, and an optimum retardation can be given as a polarizing plate for an IPS mode liquid crystal display device.

  The in-plane retardation value Ro and the retardation value Rt in the thickness direction were measured using an automatic birefringence meter Axoscan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics) under an environment of 23 ° C. and 55% RH. At a wavelength of 590 nm, three-dimensional refractive index measurement is performed, and the refractive index can be calculated from the obtained refractive indexes nx, ny, and nz.

Formula _{(i): Ro = (n} x -n y) × d (nm)
Formula _{(ii): Rt = {(} n x + n y) / 2-n z} × d (nm)
In [Equation (i) and Formula (ii), n _x represents a refractive index in the direction x in which the refractive index is maximized in the plane direction of the film. n _y, in-plane direction of the film, the refractive index in the direction y perpendicular to the direction x. _nz represents the refractive index in the thickness direction z of the film. d represents the thickness (nm) of the film. ]
In the stretching step, holding and relaxation are usually performed after stretching. That is, in this step, it is preferable to perform a stretching step of stretching the film, a holding step of holding the film in a stretched state, and a relaxation step of relaxing the film in the stretching direction in these order. In the holding stage, the stretching at the stretching ratio achieved in the stretching stage is held at the stretching temperature in the stretching stage. In the relaxation stage, after the stretching in the stretching stage is held in the holding stage, the stretching is released by releasing the tension for stretching. The relaxation step may be performed at a temperature equal to or lower than the stretching temperature in the stretching step.

(3.3) Drying Step In the drying step, the stretched film is heated and dried by the drying device 35.

  In order to adjust the amount of the organic solvent contained in the optical film, it is preferable to appropriately adjust the conditions of the drying step.

  When the film is heated by hot air or the like, a means for preventing used hot air from being mixed is preferably used by installing a nozzle capable of exhausting used hot air (air containing solvent or wetting air). The hot air temperature is more preferably in the range of 40 to 350 ° C. The drying time is preferably about 5 seconds to 60 minutes, more preferably 10 seconds to 30 minutes.

  The heating and drying means is not limited to hot air, and for example, an infrared ray, a heating roller, a microwave, or the like can be used. From the viewpoint of simplicity, it is preferable to perform drying with hot air or the like while transporting the film with the transport rollers 36 arranged in a staggered manner. The drying temperature is more preferably in the range of 40 to 350 ° C. in consideration of the amount of the residual solvent, the expansion and contraction rate in conveyance, and the like.

  In the drying step, it is preferable to dry the film until the amount of the residual solvent is generally 0.5% by mass or less.

(4) Winding Step (4.1) Knurling After a predetermined heat treatment or cooling treatment, it is preferable to provide a slitter and cut off the end before winding to obtain a good winding shape. Further, it is preferable to apply knurling to both ends of the width.

  The knurling process can be formed by pressing a heated embossing roller against a film width end. The embossing roller is formed with fine irregularities, and by pressing this, irregularities are formed on the film, and the ends can be made bulky.

  The height of the knurling at both ends of the width of the optical film of the present invention is preferably in the range of 4 to 20 μm and in the range of 5 to 20 mm.

(4.2)
As another means for obtaining a good winding form, before winding, a masking film (also referred to as a protective film) may be stacked and wound simultaneously for the purpose of preventing blocking between films, or at least a stretched film. On the other hand, preferably, the tape may be wound while both ends are taped together. The masking film is not particularly limited as long as it can protect the above film, and includes, for example, a polyethylene terephthalate film, a polyethylene film, a polypropylene film and the like.

  Further, in the present invention, it is preferable that the above-mentioned knurling process is provided after drying is completed and before winding in the film forming process.

(4.3) Winding Step This is a step of winding the film as a film after the amount of the residual solvent in the film has become 2% by mass or less. Film can be obtained.

  As the winding method, a generally used method may be used, and there are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, and the like, and these may be properly used.

[6] Physical properties of optical film <Haze>
The haze of the optical film of the present invention is preferably less than 1%, more preferably less than 0.5%. By setting the haze to less than 1%, there is an advantage that the transparency of the film becomes higher and the film can be more easily used as a film for optical use. In the optical film of the present invention, since silica particles having a uniform particle diameter are dispersed, the degree of light scattering by the particles is low, and the optical film is excellent in transparency.

  The haze value was measured at equal intervals in the width direction of the film by using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH2000) in an environment of 23 ° C. and 50% RH, and the average value was calculated. The required haze is assumed.

<Equilibrium moisture content>
The optical film of the present invention preferably has an equilibrium moisture content at 25 ° C. and a relative humidity of 60% of 4% or less, more preferably 3% or less. By setting the equilibrium water content to 4% or less, it is preferable to easily cope with a change in humidity, and the optical characteristics and dimensions are less likely to change.

  The equilibrium moisture content is determined by leaving the sample film in a room conditioned at 23 ° C. and 20% RH for 4 hours or more, and then leaving it in a room conditioned at 23 ° C. and 80% RH for 24 hours. The water is dried and vaporized at a temperature of 150 ° C. using a meter (for example, Model CA-20 manufactured by Mitsubishi Chemical Analytech Co., Ltd.), and then quantified by the Karl Fischer method.

<Film length, width, film thickness>
The optical film of the present invention is preferably long, specifically, preferably about 100 to 10,000 m long, and is wound into a roll. Further, the width of the optical film of the present invention is preferably 1 m or more, more preferably 1.3 m or more, and particularly preferably 1.3 to 4 m.

  The film thickness of the stretched film is preferably in the range of 5 to 40 μm from the viewpoint of reducing the thickness of the display device and productivity. When the film thickness is 5 μm or more, a certain or more film strength and retardation can be exhibited. When the film thickness is 40 μm or less, the film has a desired retardation and can be applied to thin polarizing plates and display devices. Preferably, the thickness of the film is in the range of 10 to 30 μm.

[7] Application of Optical Film The optical film of the present invention is preferably a functional film used for various display devices such as a liquid crystal display device and an organic EL display device, and a touch panel. Specifically, the optical film of the present invention is a polarizing plate protective film, a retardation film, an antireflection film, a brightness enhancement film, a hard coat film, an antiglare film, and an antistatic film for a liquid crystal display device or an organic EL display device. And an optical compensation film for expanding the viewing angle. Typically, the optical film of the present invention is a polarizing plate protective film. The optical film of the present invention can also be used as a polarizing plate protective film that also serves as the retardation film.

[7.1] Polarizing plate [7.1.1] Polarizer A polarizer is an element that transmits only light having a polarization plane in a certain direction, and examples thereof include a polyvinyl alcohol-based polarizing film.

  Polyvinyl alcohol-based polarizing films include those obtained by dyeing a polyvinyl alcohol-based film with iodine and those obtained by dyeing a dichroic dye.

  The polarizer can be obtained by uniaxially stretching the polyvinyl alcohol film and then dyeing, or dyeing the polyvinyl alcohol film and then uniaxially stretching the film, and preferably further performing a durability treatment with a boron compound.

  The thickness of the polarizer is preferably in the range of 5 to 30 μm, and more preferably in the range of 5 to 15 μm.

  Examples of the polyvinyl alcohol film include a content of ethylene units of 1 to 4 mol%, a degree of polymerization of 2,000 to 4,000, and a degree of saponification of 99.0 to 99 described in JP-A-2003-248123, JP-A-2003-342322, and the like. .99 mol% of ethylene-modified polyvinyl alcohol is preferably used. In addition, it is preferable that a polarizer is manufactured by a method described in JP-A-2011-100161, Japanese Patent No. 4691205, and Japanese Patent No. 4804589 and bonded to the optics of the present invention to manufacture a polarizing plate.

[7.1.2] Adhesive [water glue]
In the polarizing plate used in the present invention, it is preferable that the optical film of the present invention is bonded to a polarizer using a completely saponified polyvinyl alcohol aqueous solution (water paste). Another polarizing plate protective film can be bonded to the other surface. When the optical film of the present invention is used as a liquid crystal display device, it is preferable that the optical film of the present invention be provided on the liquid crystal cell side of the polarizer. Either can be used.

  For example, as a conventional polarizing plate protective film, commercially available cellulose ester films (for example, Konica Minolta Tac KC8UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC6UY, KC6UA, KC4UY, KC4UE, KC8UE, KC8UE, XC8UE, XC8UE, XC8UE, XC8UE) RHA, KC8UXW-RHA-C, KC8UXW-RHA-NC, and KC4UXW-RHA-NC, all of which are manufactured by Konica Minolta, Inc.) are preferably used.

[Active energy ray-curable adhesive]
Further, in the polarizing plate used in the present invention, it is preferable that the optical film of the present invention and the polarizer are bonded with an active energy ray-curable adhesive.

  As the active energy ray-curable adhesive, the following ultraviolet-curable adhesive is preferably used.

  In the present invention, by applying an ultraviolet curable adhesive to the bonding of the optical film and the polarizer, it is possible to obtain a polarizing plate having high strength even in a thin film and excellent in flatness.

<Composition of UV-curable adhesive>
As an ultraviolet-curable adhesive composition for a polarizing plate, a photo-radical polymerization type composition using photo-radical polymerization, a photo-cation polymerization type composition using photo-cation polymerization, and a combination of photo-radical polymerization and photo-cation polymerization Hybrid compositions are known.

  As the photoradical polymerization type composition, a specific ratio of a radical polymerizable compound containing a polar group such as a hydroxy group or a carboxy group and a radical polymerizable compound not containing a polar group described in JP-A-2008-09329 are included. Compositions) are known. In particular, the radical polymerizable compound is preferably a compound having a radically polymerizable ethylenically unsaturated bond. Preferred examples of the compound having an ethylenically unsaturated bond capable of undergoing radical polymerization include a compound having a (meth) acryloyl group. Examples of the compound having a (meth) acryloyl group include an N-substituted (meth) acrylamide compound, a (meth) acrylate compound, and the like. (Meth) acrylamide means acrylamide or methacrylamide.

  Further, as the cationic photopolymerizable composition, (α) cationic polymerizable compound, (β) cationic photopolymerization initiator, and (γ) wavelength longer than 380 nm as disclosed in JP-A-2011-028234. UV-curable adhesive compositions containing each component of a photosensitizer exhibiting a maximum absorption of the above-mentioned light and (δ) a naphthalene-based photosensitizer. However, other UV-curable adhesives may be used.

(1) Pretreatment Step The pretreatment step is a step of performing an easy adhesion treatment on the surface of the optical film to be adhered to the polarizer. Examples of the easy adhesion treatment include a corona treatment and a plasma treatment.

(Application process of UV curable adhesive)
In the step of applying the ultraviolet-curable adhesive, the ultraviolet-curable adhesive is applied to at least one of the bonding surfaces of the polarizer and the optical film. When an ultraviolet-curable adhesive is directly applied to the surface of a polarizer or an optical film, there is no particular limitation on the application method. For example, various wet coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. Further, a method in which an ultraviolet-curable adhesive is cast between the polarizer and the optical film, and then uniformly spread by pressing with a roller or the like can also be used.

(2) Laminating Step After applying the ultraviolet-curable adhesive by the above method, it is processed in the laminating step. In this bonding step, for example, when an ultraviolet curable adhesive is applied to the surface of the polarizer in the previous coating step, the optical film is superposed thereon. In the case of a method in which an ultraviolet curable adhesive is first applied to the surface of an optical film, a polarizer is superposed thereon. When an ultraviolet curable adhesive is cast between the polarizer and the optical film, the polarizer and the optical film are superposed in that state. Usually, in this state, pressure is applied between both sides of the optical film by a pressure roller or the like. As the material of the pressure roller, metal, rubber, or the like can be used. The pressure rollers arranged on both sides may be made of the same material or different materials.

(3) Curing Step In the curing step, an uncured UV-curable adhesive is irradiated with ultraviolet light to emit a cationically polymerizable compound (for example, an epoxy compound or an oxetane compound) or a radically polymerizable compound (for example, an acrylate compound or acrylamide). An ultraviolet curable adhesive layer containing the compound (e.g., a base compound or the like) is cured, and the laminated polarizer and the optical film are adhered via the ultraviolet curable adhesive. When bonding an optical film to one surface of a polarizer, the active energy ray may be irradiated from either the polarizer side or the optical film side. In addition, when bonding the optical film to both sides of the polarizer, irradiate ultraviolet rays in a state where the optical film is laminated on both sides of the polarizer via the ultraviolet-curable adhesive respectively, and the ultraviolet-curable adhesive on both sides is applied. Are simultaneously cured.

As the irradiation condition of the ultraviolet ray, any appropriate condition can be adopted as long as it can cure the ultraviolet curable adhesive applied to the present invention. Preferably the dose of ultraviolet rays in the range of 50~1500mJ / cm ² in accumulated light quantity, and even more preferably in the range of 100 to 500 mJ / cm ^2.

  When the manufacturing process of the polarizing plate is performed in a continuous line, the line speed depends on the curing time of the adhesive, but is preferably in the range of 1 to 500 m / min, more preferably in the range of 5 to 300 m / min, and still more preferably in the range of 10 to 300 m / min. The range is 100 m / min. When the line speed is 1 m / min or more, productivity can be secured, or damage to the optical film can be suppressed, and a polarizing plate having excellent durability can be manufactured. When the line speed is 500 m / min or less, the curing of the ultraviolet-curable adhesive is sufficient, and the ultraviolet-curable adhesive layer having the desired hardness and excellent adhesiveness can be formed.

[7.1.3] Protective film The film disposed on the side of the polarizer opposite to the optical film of the present invention is preferably a film that functions as a protective film for the polarizer.

  As such a protective film, the optical film of the present invention may be used. , KC4UH, KC6UAH, KC6UAH, KC6UAH, KC6UAH, KC6UAH, KC6UAH, KC6UAH, KC4UA, KC4UAH TD60UL, FUJITAC TD40UL, FUJITAC R02, FUJITAC R06, all of which are manufactured by FUJIFILM Corporation. Can.

  Further, for example, resin films such as polyethylene terephthalate, polyethylene naphthalate, and polycarbonate, alicyclic polyolefins (for example, ZEONOR (registered trademark), polyarylate, polyether sulfone, polysulfone, cycloolefin copolymer, polyimide manufactured by Zeon Corporation) (For example, NeoPrim (registered trademark) manufactured by Mitsubishi Gas Chemical Company, Ltd.), resin films such as fluorene ring-modified polycarbonate, alicyclic-modified polycarbonate, and acryloyl compounds (the glass transition temperature Tg is shown in parentheses). Among the resin base materials, in terms of cost and availability, polyethylene terephthalate (abbreviation: PET), polybutylene terephthalate, polyethylene naphthalate (abbreviation: PEN), polycarbonate (abbreviation: PC) Film etc. is preferably used as a protective film.

  The thickness of the protective film is not particularly limited, but can be about 10 to 200 μm, preferably in the range of 10 to 100 μm, and more preferably in the range of 10 to 70 μm.

[7.2] Liquid crystal display device By using a polarizing plate to which the optical film of the present invention is pasted for a liquid crystal display device, various liquid crystal display devices excellent in visibility and used in the present invention can be manufactured. .

  Further, the optical film of the present invention is preferably used for a polarizing plate for display applications having a polygonal or curved line, and when punching with a free form, cracks such as sacrifices and cracks are generated on the end face or cutting chips due to cutting. Can be solved.

  The polarizing plate used in the present invention can be used for liquid crystal display devices of various driving systems such as STN, TN, OCB, HAN, VA (MVA, PVA), IPS, and OCB. Preferably, a VA (MVA, PVA) type liquid crystal display device and an IPS type liquid crystal display device are used.

  In a liquid crystal display device, two polarizing plates, a polarizing plate on the viewing side and a polarizing plate on the backlight side, are usually used. However, it is also preferable to use the polarizing plate used in the present invention as both polarizing plates. It is also preferable to use it as a polarizing plate. In particular, the polarizing plate used in the present invention is preferably used as a polarizing plate on the viewing side that directly contacts the external environment. When the optical film of the present invention is a protective film, the viewing side surface, or the optical film of the present invention is optically compensated. In the case of a film, it is preferably arranged on the liquid crystal cell side. When used as an optical compensation film for an IPS-type liquid crystal display device, it is preferable to dispose it on both sides of a liquid crystal cell.

  In addition, a polarizing plate other than the present invention can be used as the polarizing plate on the backlight side. In this case, both surfaces of the polarizer may be coated on a commercially available cellulose ester film (for example, Konica Minoltac KC8UX, KC5UX, KC4UX, KC8UCR3). , KC4SR, KC4BR, KC4CR, KC4DR, KC4FR, KC4KR, KC8UY, KC6UY, KC4UY, KC4UE, KC8UE, KC8UY-HA, KC2UA, KC4UA, KC6UA, KC4UAH, CC4UAH, CC4UAHK FUJITAC T60UZ, FUJITAC T80UZ, FUJITAC TD80UL, FUJITAC TD60UL, FUJITAC TD40UL, FUJITAC R02, FUJITAC R06, Fujifilm Corporation Polarizing plate stuck to manufacturing, etc.) are preferably used.

  Further, as the backlight-side polarizing plate, using the optical film of the present invention on the liquid crystal cell side of the polarizer, the commercially available protective film or retardation film on the opposite surface, a polyester film, an acrylic film, a polycarbonate film, or A polarizing plate bonded with another cycloolefin film can also be preferably used.

  By using the polarizing plate used in the present invention, a liquid crystal display device having excellent visibility such as display unevenness and front contrast can be obtained even for a large-sized liquid crystal display device having a screen of 30 inches or more.

[7.3] Organic electroluminescent display device The optical film using the cycloolefin resin of the present invention has good workability due to good slipperiness, and is also suitable for an organic electroluminescent display device having, for example, a curved surface shape. is there.

  For an outline of an organic EL device applicable to the organic electroluminescence display device used in the present invention, for example, JP-A-2013-157634, JP-A-2013-168552, JP-A-2013-177361, and JP-A-2013-177361. JP-A-2013-187221, JP-A-2013-191644, JP-A-2013-191804, JP-A-2013-225678, JP-A-2013-235994, JP-A-2013-243234, JP-A-2013-2013 JP-A-243236, JP-A-2013-242366, JP-A-2013-243371, JP-A-2013-245179, JP-A-2014-003249, JP-A-2014-003299, and JP-A-2014-139910. Gazette, JP 2014-01 493 JP include a configuration described in JP-2014-017494 Patent Publication.

  Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. In the examples, “parts” or “%” is used, but “parts by mass” or “% by mass” is used unless otherwise specified.

<Preparation of optical film 101>
(Synthesis of cycloolefin resin P)
8-methyl-8-methoxycarbonyltetracyclo [4.4.0.12,5. 17,10] -3-Dodecene (DNM) 75% by mass, dicyclopentadiene (DCP) 24% by mass, 2-norbornene 1% by mass, 9 parts of 1-hexene as a molecular weight regulator and 200 parts of toluene were replaced with nitrogen. The reaction vessel was charged and heated to 110 ° C. 0.005 part of triethylaluminum and 0.005 part of methanol-modified WCl6 (anhydrous methanol: PhPOCl2: WCl6 = 103: 630: 427 mass ratio) were added and reacted for 1 hour to obtain a polymer. The obtained polymer solution was put in an autoclave, and 200 parts of toluene was further added. Next, 0.006 parts of RuHCl (CO) [P (C ₆ H ₅ )] ₃ as a hydrogenation catalyst was added and heated to 90 ° C., and then hydrogen gas was charged into the reactor, and the pressure was increased to 10 MPa. did. Thereafter, the reaction was performed at 165 ° C. for 3 hours while maintaining the pressure at 10 MPa. After completion of the reaction, the resultant was precipitated in a large amount of a methanol solution, and the precipitate was purified by reprecipitation using toluene and methanol to obtain a copolymer P.

The copolymer P had a weight-average molecular weight (Mw) of 7.2 × 10 ⁴ , a molecular weight distribution (Mw / Mn) of 3.3, and an intrinsic viscosity (ηinh) of 0.3 as determined by gel permeation chromatography (GPC). 59, the glass transition temperature (Tg) was 143 ° C. When the methoxycarbonyl group addition rate of the copolymer P was determined by ¹³ CNMR measurement, it was confirmed that 75% by mass of the monomer having a methoxycarbonyl group was added. The copolymer P obtained above is a cycloolefin resin P containing 75% by mass of a monomer having a methoxycarbonyl group as a hydrogen bond-accepting group.

(Preparation of fine particle dispersion)
Silica fine particles (Aerosil R812, manufactured by Nippon Aerosil Co., Ltd.) 11% by mass
89% by mass of dichloromethane
After stirring and mixing the above with a dissolver for 50 minutes, dispersion was performed using a Manton-Gaulin disperser to prepare a fine particle dispersion.
(Preparation of fine particle addition liquid 1)
Dichloromethane was placed in a dissolution tank, and the above-prepared fine particle dispersion was slowly added to 50 mass% while sufficiently stirring dichloromethane. Further, dispersion was performed with an attritor so that the particle size of the secondary particles became a predetermined size. This was filtered with Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle-added liquid 1.
(Preparation of dope A)
The cycloolefin resin P synthesized above was charged into a pressurized dissolution tank containing ethanol while stirring. Next, the fine particle addition liquid was added so as to have the addition amount shown in Table 1, and then heated at the dissolution temperature shown in Table 3 for 3 hours and completely dissolved with stirring. Thereafter, Azumi Filter Paper No. No. manufactured by Azumi Filter Paper Co., Ltd. Filtration was performed using 244 to prepare Dope A. The composition of the dope A is shown below.

Cycloolefin resin P 100.0% by mass
290.0% by mass of dichloromethane
Fine particle addition liquid 27.3% by mass
Hindered phenolic compound (aggregation inhibitor A) 0.1% by mass
The dope A prepared above was cast on a stainless steel casting support (support temperature: 22 ° C.) using a band casting apparatus. The film was peeled off in a state where the amount of the residual solvent in the dope A was approximately 20% by mass, and both ends in the width direction of the film were gripped with a tenter. It was dried while being stretched 1.01 times (1%). Thereafter, the film was further dried by being conveyed between rolls of a heat treatment apparatus at 90 ° C. for 30 minutes to produce an optical film 101. The thickness was 15 μm and the width was 1492 mm.

  As the hindered phenol compound (anticoagulant A), IRGANOX1076 (manufactured by BSF Japan Ltd.) was used.

<Preparation of optical film 102>
(Preparation of fine particle dispersion)
Silica fine particles (Aerosil R812: Trimethylsilane treated product, manufactured by Nippon Aerosil Co., Ltd.) 11% by mass
89% by mass of ethanol
After stirring and mixing the above with a dissolver for 50 minutes, dispersion was performed using a Manton-Gaulin disperser to prepare a fine particle dispersion.
(Preparation of fine particle addition liquid 1)
Dichloromethane was placed in a dissolution tank, and the above-prepared fine particle dispersion was slowly added to 50 mass% while sufficiently stirring dichloromethane. Further, dispersion was performed with an attritor so that the particle size of the secondary particles became a predetermined size. This was filtered with Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle-added liquid 1.

(Preparation of dope B)
The cycloolefin resin P synthesized above was charged into a pressurized dissolution tank containing ethanol while stirring. Next, the fine particle addition liquid was added so as to have the addition amount shown in Table 1, and then heated at the dissolution temperature shown in Table 3 for 3 hours and completely dissolved with stirring. Thereafter, Azumi Filter Paper No. No. manufactured by Azumi Filter Paper Co., Ltd. Filtration was performed using 244 to prepare Dope B. The composition of the dope B is shown below.

Cycloolefin resin P 100.0% by mass
290.0% by mass of dichloromethane
Ethanol 10.0% by mass
Distilled water 1.0% by mass
Fine particle addition liquid 27.3% by mass
Using a band casting apparatus, the prepared dope B was cast on a stainless steel casting support (support temperature: 22 ° C.). The film was peeled off in a state where the amount of the residual solvent in the dope B was approximately 20% by mass, and both ends in the width direction of the film were gripped with a tenter. It was dried while being stretched 1.01 times (1%). Thereafter, the film was further dried by being conveyed between rolls of a heat treatment apparatus at 90 ° C. for 30 minutes to produce an optical film 101. The thickness was 15 μm and the width was 1492 mm.

<Preparation of optical film 103>
An optical film 103 was produced in the same manner as in the production of the optical film 102 except that the following dope C was used.

(Preparation of dope C)
The cycloolefin resin P synthesized above was charged into a pressurized dissolution tank containing ethanol while stirring, and then heated at a dissolution temperature shown in Table 1 for 3 hours, and completely dissolved while stirring. Thereafter, Azumi Filter Paper No. No. manufactured by Azumi Filter Paper Co., Ltd. Filtration was performed using 244 to prepare Dope C. The composition of the dope C is shown below.

Cycloolefin resin P 100.0% by mass
290.0% by mass of dichloromethane
Ethanol 10.0% by mass
Distilled water 1.0% by mass
Hindered phenol compound (aggregation inhibitor A) 0.3% by mass
<Preparation of optical film 104>
An optical film 104 was produced in the same manner as in the production of the optical film 102 except that the following dope D was used.

(Dope D)
Cycloolefin resin P 100.0% by mass
290.0% by mass of dichloromethane
Ethanol 10.0% by mass
Distilled water 1.0% by mass
Particle addition liquid 0.91% by mass
Hindered phenol compound (aggregation inhibitor A) 0.3% by mass
<Preparation of optical films 105 to 108>
In the production of the optical film 104, optical films 105 to 108 were produced in the same manner except that the addition amount of the silica particles was changed as shown in Table 1.

<Preparation of optical films 109 to 113>
In the production of the optical film 104, optical films 109 to 113 were produced in the same manner except that the kind of the silica particles was changed as shown in Table 1.

  In the table, R805, R976S, RY300, 200V and R812S are all products of the Aerosil series manufactured by Nippon Aerosil Co., Ltd.

R805: Octylsilane treated product R976S: Dimethylsilane treated product RY300: Dimethylpolysiloxane treated product 200V: Untreated product R812S: Trimethylsilane treated product <Preparation of optical films 114 to 118>
Optical films 114 to 118 were produced in the same manner as in the production of the optical film 104 except that the amount of the hindered phenol compound (aggregation inhibitor A) was changed as shown in Table 1.

  Further, for the optical film 118, a hindered phenol-based compound (anti-aggregation agent B): IRGANOX1010 (manufactured by BSF Japan Ltd.) was used instead of the hindered phenol-based compound (anti-aggregation agent A).

<Preparation of optical films 119 to 122>
In the production of the optical film 104, the optical films 119 to 122 were produced in the same manner except that the amount of ethanol and the drying temperature and the drying time were changed so that the amount of ethanol in the film became the amount shown in Table 2. .

Specifically, they were manufactured under the following conditions.
The optical film 119 was conveyed by adding 5 parts by mass of ethanol of the dope composition and maintaining the temperature of the drying heat treatment apparatus after stretching at 110 ° C. for 50 minutes.

  The optical film 120 was conveyed by adding 5 parts by weight of ethanol of the dope composition and the temperature of the drying heat treatment apparatus after stretching at 90 ° C. for 30 minutes.

  The optical film 121 was conveyed by adding 20 parts by mass of ethanol of the dope composition and the temperature of the drying heat treatment apparatus after stretching at 9 ° C. for 30 minutes.

  The optical film 122 was transported at a dope composition of 22 parts by mass of ethanol and at a temperature of 90 ° C. for 30 minutes at 90 ° C. after stretching.

<Preparation of optical films 123 and 124>
The optical films 123 and 124 were produced in the same manner as in the production of the optical film 106 except that the dissolution temperature of the dope was changed to 55 ° C. and 10 ° C., respectively.

<Preparation of optical film 125>
(Preparation of cycloolefin resin Q synthesis solution)
Silica fine particles, 10-undecenoic acid, a phenol-based stabilizer, a phosphorous-based stabilizer, a hindered amine-based light stabilizer are added to the following norbornene-based monomer mixture to dissolve or disperse, and further triphenylphosphine, represented by the following compound C The ruthenium catalyst was added and mixed with a line mixer to prepare a cycloolefin resin Q synthetic solution having no hydrogen bond-accepting group. The composition of the cycloolefin resin Q synthesis solution is shown below.
(Composition of cycloolefin resin Q synthesis solution)
Norbornene-based monomer mixture (90 parts of dicyclopentadiene, 10 parts of tricyclopentadiene) 100.0% by mass
Silica fine particles (Aerosil R812 Nippon Aerosil Co., Ltd.) 1.6% by mass
10-undecenoic acid 0.3% by mass
Hindered phenolic compound (aggregation inhibitor A) 0.1% by mass
Phosphorus stabilizer 1.0% by mass
1.0% by mass of triphenylphosphine
1.6 mass% ruthenium catalyst

  The cycloolefin-based resin Q synthetic solution prepared above was coated at 25 ° C. on a 0.075 mm-thick polyethylene terephthalate carrier film to form a cast film, and then immediately, separately prepared from the top of the coating layer. A similar carrier film was laminated. Thereafter, heating is performed at 200 ° C. for 3 minutes, and then, after cooling to 20 ° C., the upper and lower carrier films are separated from each other, and the optical film 125 mainly composed of cycloolefin-based resin Q having no hydrogen bonding acceptor group ( The thickness was 15 μm and the width was 1492 mm).

<Preparation of optical film 126>
An optical film 126 was produced in the same manner as in the production of the optical film 106 except that the following dope E was used.

(Dope E)
Cycloolefin resin P 100.0% by mass
290.0% by mass of dichloromethane
Ethanol 10.0% by mass
Fine particle addition liquid 27.3% by mass
Hindered phenol compound (aggregation inhibitor A) 0.3% by mass
<Preparation of optical film 127>
An optical film 127 was produced in the same manner as in the production of the optical film 106 except that the following dope F was used.

(Dope F)
Cycloolefin resin P 100.0% by mass
290.0% by mass of dichloromethane
8.0% by mass of methanol
Distilled water 1.0% by mass
Fine particle addition liquid 27.3% by mass
Hindered phenol compound (aggregation inhibitor A) 0.3% by mass
<Preparation of optical film 128>
An optical film 128 was produced in the same manner as in the production of the optical film 106 except that the following dope G was used. As the cycloolefin resin R used here, Arton G7810 manufactured by JSR Corporation and containing 0.25% by mass of a hindered phenol compound (aggregation inhibitor A) based on 100 parts by mass was used.

(Dope G)
Cycloolefin resin R (JSR Corporation ARTON G7810)
100.0% by mass
290.0% by mass of dichloromethane
Ethanol 10.0% by mass
Distilled water 1.0% by mass
Fine particle addition liquid 27.3% by mass
<Preparation of optical films 129 and 130>
In the production of the optical film 106, the dope was coated at 25 ° C. on a 0.075 mm-thick polyethylene terephthalate carrier film to form a cast film. The film was laminated. Thereafter, heating is performed at 200 ° C. for 3 minutes, and then, after cooling to 20 ° C., the upper and lower carrier films are peeled off, and the optical film 129 (thickness is 3 μm, the width is 1492 mm) and the optical film 130 (thickness Is 5 μm and the width is 1492 mm).

≪Evaluation≫
The following evaluation was performed using the optical films 101 to 130 produced above.

[1] Measurement of Hydrophobicity of Silica Particles The hydrophobicity of silica particles can be measured by the methanol wettability method (hereinafter referred to as MW method) using the methanol wettability value (hereinafter referred to as MW value) obtained by the present method. ).

  In the above-mentioned MW method, in order to quantify the degree of hydrophobicity of the fine particles, a first solution and a second solution in which methanol and pure water were mixed were used. At this time, the mixing ratio of methanol to pure water is 3: 7 in the first solution and 6: 4 in the second solution. Then, the same amount of the fine particles is added to each solution and stirred and mixed. Each mixed solution is centrifuged to determine the volume of the precipitate of the fine particles, and the volume of the precipitate of the fine particles in the first solution is determined. MW value in the first solution = (t / A) × 100 [%], and MW value in the second solution, where tmL and the volume of the sediment of the fine particles in the second solution were smL. = (S / A) x 100 [%]. Here, A is the volume (AmL) of the silica particles added first.

[MW method]
(1) A first solution A is prepared by mixing a methanol solution C and pure water D at a volume ratio of 3: 7 (for example, 40 ml of methanol solution C and pure water D 60mL)
(2) Next, 0.2 g of the silica particle powder E and 7 mL of the first solution A are put into a 10 mL settling tube F.
(3) Cap the sedimentation tube F, and shake and mix the fine particle powder E into the first solution A using a Turbula mixer. At this time, the condition of the turbulator mixer is 90 rpm for 30 seconds.
(4) A centrifugal separator is used to settle the silica particle powder E. The condition of the centrifuge is 3500 rpm for 10 minutes.
(5) The volume of the sediment amount of the settled fine particle powder E that can be read on the scale of the sedimentation tube is read, and the value is set to tmL.
(6) A second solution B is prepared by newly mixing the methanol solution C and the pure water D so that the volume ratio becomes 6: 4 (for example, the methanol solution C is pure water with respect to 60 mL. (Water D is 40 mL).
(7) Using the second solution B, prepare a sediment of the silica particle powder E by the same procedure (8) to (11) as in the above (2) to (5) and read it on the scale of the sedimentation tube. The amount of sediment of the precipitated silica particle powder E is read as a volume, and the value is defined as smL.
(12) The MW value (%) is obtained by the following equation.

MW value in first solution = (t / A) × 100 [%]
MW value in second solution = (s / A) × 100 [%]
Here, A is the volume (AmL) of the silica particles added first.

[2] Average particle size of silica particles The average particle size of the silica particles was measured by the following method.

  The measurement of the particle diameter of the silica particles in the optical film is performed by taking a cross section of the film cut by a microtome at an appropriate magnification with a scanning electron microscope (SEM), and measuring 100 particles included in the tomographic cut photograph. Is measured, and the average value is determined to be the average particle size. The particle diameter was the diameter when the cross section of the particle was circular, and the area was calculated when the cross section was not circular, and the diameter was converted to a circular shape.

SEM: JSM-6060LA (JEOL: JEOL Ltd.)
Microtome: Leica EM UC6
[3] Amount of ethanol, methanol and distilled water in the film The amount of ethanol and methanol in the film were measured by the following method.

  The residual amounts of the alcohol and distilled water used as solvent components were measured by the following measurement methods.

  The optical film cut into a certain shape was placed in a 20 mL closed glass container, and treated at 120 ° C. for 20 minutes, followed by gas chromatography (equipment: HP 5890SERIES II, column: J & W DB-WAX (0.32 mm inner diameter, The length was measured at a temperature of 40 ° C. for 5 minutes, and then the temperature was raised to 100 ° C. at 80 ° C./min.

[4] Vertical Wrinkle A sample having a size of 90 cm in width and 100 cm in length was cut out from the produced optical film and placed on a table. Five 40 W fluorescent lamps (“FLR40S-EX-D / M” manufactured by Panasonic Corporation) are arranged, and 1.5 m from the table is illuminated so that the sample is irradiated with light from a 45 ° angle. Fixed to height. The sample was illuminated by turning on the fluorescent lamp, the surface of the sample was visually observed, and evaluated according to the following criteria.
○: All five fluorescent lamps appear straight △: Some fluorescent lamps appear to be bent
×: The fluorescent lamp appears to be bent as a whole

[5] Polarizing plate punching crack A polarizing plate was produced using the optical films 101 to 130 produced above.
A roll-shaped polyvinyl alcohol film having a thickness of 30 μm was continuously stretched 5 times in an aqueous iodine solution and dried to obtain a polarizer having a thickness of 7 μm.

  Next, the above-prepared polarizer was sandwiched from both sides by the produced optical films 101 to 130, and bonded via an ultraviolet-curable adhesive liquid described below to produce a polarizing plate.

  At that time, they were bonded so that the absorption axis of the polarizer was orthogonal to the slow axis of the optical film of the present invention.

[Preparation of UV-curable adhesive liquid 1]
After mixing the following components, the mixture was defoamed to prepare an ultraviolet-curable adhesive liquid 1. The triarylsulfonium hexafluorophosphate was blended as a 50% propylene carbonate solution, and the solid content of the triarylsulfonium hexafluorophosphate is shown below.

3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 45 parts by mass Eporide GT-301 (alicyclic epoxy resin manufactured by Daicel) 40 parts by mass 1,4-butanediol diglycidyl ether 15 parts by mass Tria Reel sulfonium hexafluorophosphate 2.3 parts by mass 9,10-dibutoxyanthracene 0.1 part by mass 1,4-diethoxynaphthalene 2.0 parts by mass In the production of a polarizing plate, the corona output strength was 2. A corona discharge treatment is performed at 0 kW and a line speed of 18 m / min, and the ultraviolet curable adhesive liquid 1 prepared above is coated on the corona discharge treated surface with a bar coater so that the film thickness after curing becomes about 3 μm. Thus, an ultraviolet curable adhesive layer was formed.

The polarizing plate is irradiated with ultraviolet light from one optical film side using an ultraviolet irradiation device with a belt conveyor (the lamp uses a D bulb manufactured by Fusion UV Systems) so that the integrated light amount becomes 750 mJ / cm ^2. Then, the ultraviolet curable adhesive layer was cured.

The obtained polarizing plate is punched with a blade having a size of 20 cm in a direction of an absorption axis of a polarizer and a size of 10 cm in a direction perpendicular to the absorption axis, and a rectangular corner having a 2R bent corner, and formed into a glass plate via an adhesive layer. Lamination is performed to obtain a sample. After leaving the sample in an atmosphere of -40 ° C for 30 minutes, it is left in an atmosphere of 90 ° C for 30 minutes, and this operation is defined as one cycle. After repeating the cycle according to the following criteria, the polarizing plate was observed, and if a crack had occurred, its length was measured. At the same time, the degree of polarization of the polarizing plate was also measured and evaluated according to the criteria shown below.
<Crack evaluation>
：: No crack generation even at 500 cycles or 1 cm or less even if generated. Δ: No crack generation or even 1 cm or less from 250 to 500 cycles. ×: No crack generation or 250 cm or less until 250 cycles.

[6] Evaluation of Cutting Chips The state of generation of chips when the polarizing plate was cut was observed with an optical microscope, and the presence or absence of cut chips of 5 μm or more at 1 cm from the cut portion was observed.
○: No chip generation ×: Chip generation

[7] Transparency (haze)
The haze (%) of the optical film was measured using a commercially available haze meter (manufactured by Nippon Denshoku Co., Ltd., product name "NDH 2000") in accordance with JIS K-7136, and evaluated according to the following criteria. If the haze is less than 0.5%, it can be used for various devices as a transparent optical film.
：: less than 0.5% ×: 0.5% or more

[8] Retardation The in-plane retardation value Ro and the thickness direction retardation value Rt are measured at 23 ° C. and 55% using an automatic birefringence meter Axoscan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics). The three-dimensional refractive index is measured at a wavelength of 590 nm in an environment of RH, and is calculated from the obtained refractive indices nx, ny, and nz using the following equation.

Formula _{(i): Ro = (n} x -n y) × d (nm)
Formula _{(ii): Rt = {(} n x + n y) / 2-n z} × d (nm)
In [Equation (i) and Formula (ii), n _x represents a refractive index in the direction x in which the refractive index is maximized in the plane direction of the film. n _y, in-plane direction of the film, the refractive index in the direction y perpendicular to the direction x. _nz represents the refractive index in the thickness direction z of the film. d represents the thickness (nm) of the film. ]
[9] Visibility: Characteristic evaluation as liquid crystal display device The polarizing plate of the product name “XPERIA Z4 Tablet” manufactured by Sony Mobile Communications Inc., which is an IPS type tablet type liquid crystal display device, was peeled off, and the liquid crystal cell was sandwiched. Attach the two polarizing plates so that they are orthogonal to each other so that the polarizing axes of the polarizing plates do not change from the original. Attach black tape from the display side so that light does not leak in places not sandwiched between the polarizing plates. When a simple IPS-type color liquid crystal display was manufactured and the characteristics of the optical film as a polarizing plate were evaluated, the liquid crystal display device using the polarizing plate of the present invention was compared with a liquid crystal television before the polarizing plate was removed. Also exhibited excellent contrast performance and excellent display properties without color unevenness.
：: No problem in both contrast and color unevenness X: Clear deterioration was observed in either contrast or color unevenness

[10] Coloring The obtained sheet was placed on white paper and the degree of coloring was visually evaluated.
：: No coloring is observed Δ: Slightly yellow coloring is observed X: Yellow coloring is clearly observed [11] Bright spot foreign matter The bright spot foreign matter of the film was measured by the following method.
Two polarizing plates are arranged in an orthogonal state (crossed Nicols) to block transmitted light, and the prepared sample is placed between the two polarizing plates. The polarizing plate used was a glass protective plate. Light was irradiated from one side, and the number of bright spots having a diameter of 0.01 mm or more per 100 cm ² was counted from the opposite side with an optical microscope (50 times). The smaller the number of bright spot foreign substances, the better the characteristics.
○: 0 to 2 pieces
Δ: 3 to 12 ×: 13 or more ○, Δ can be used practically.

  Tables 1 and 2 collectively show the structure of the optical film and the above evaluation results.

  From Tables 1 and 2, the optical film of the present invention contains a cycloolefin-based resin having a hydrogen bond-accepting group, an alcohol-based solvent, a hindered phenol-based compound, water, and silica particles having a specific hydrophobicity. As a result, the generation of punch cracks and cutting chips is remarkably reduced, and at the same time, it is excellent in vertical wrinkles, transparency, phase difference, visibility of IPS mode type liquid crystal display devices, coloring and bright spot foreign matter. It can be seen that an optical film using a cycloolefin-based resin having excellent excellent properties was obtained.

DESCRIPTION OF SYMBOLS 1 Dissolution pot 3, 6, 12, 15 Filtration device 4, 13 Stock pot 2, 5, 11, 14 Liquid feed pump 8, 16 Conduit 10 Additive supply pot 20 Confluence pipe 21 Mixer 30 Pressure die 31 Metal support 32 Web 33 Peeling position 34 Stretching device 35 Drying device 36 Conveying roller 37 Winding device 41 Charging pot 42 Stock pot 43 Pump

Claims (6)

An optical film containing a cycloolefin-based resin,
The cycloolefin-based resin is a cycloolefin-based resin having at least one hydrogen bond-accepting group,
The film contains an alcohol solvent in a range of 10 to 1000 ppm, a hindered phenol compound in a range of 0.1 to 0.5% by mass , and
The degree of hydrophobicity measured by the methanol wettability method is such that when the first solution having a volume ratio of methanol to pure water of 3: 7 is used, the degree of hydrophobicity is 20% or less, and the volume of methanol and pure water is not more than 20%. Optics characterized by containing silica particles having a hydrophobicity of 80% or more when the second solution having a ratio of 6: 4 is used is 0.1 to 2.5% by mass based on the total mass of the film. the film.   The optical film according to claim 1, wherein a secondary average particle diameter of the silica particles in the film is in a range of 100 to 400 nm. The film thickness d of the optical film is 5 μm ≦ d ≦ 40 μm, and the in-plane retardation Ro and the thickness direction retardation Rt at a measurement wavelength of 590 nm are Ro ≦ 5 nm and −15 nm ≦ Rt ≦ 15 nm, respectively. The optical film according to claim 1 or 2, wherein An optical film containing a cycloolefin-based resin,
The cycloolefin-based resin is a cycloolefin-based resin having at least one hydrogen bond-accepting group,
The film contains an alcohol-based solvent and a hindered phenolic compound, and further contains water in a range of 50 to 500 ppm , and
The degree of hydrophobicity measured by the methanol wettability method is such that when the first solution having a volume ratio of methanol to pure water of 3: 7 is used, the degree of hydrophobicity is 20% or less, and the volume of methanol and pure water is not more than 20%. Optics characterized by containing silica particles having a hydrophobicity of 80% or more when the second solution having a ratio of 6: 4 is used is 0.1 to 2.5% by mass based on the total mass of the film. the film. The optical film according to claim 4 , wherein a secondary average particle diameter of the silica particles in the film is in a range of 100 to 400 nm. The film thickness d of the optical film is 5 μm ≦ d ≦ 40 μm, and the in-plane retardation Ro and the thickness direction retardation Rt at a measurement wavelength of 590 nm are Ro ≦ 5 nm and −15 nm ≦ Rt ≦ 15 nm, respectively. The optical film according to claim 4 or 5, wherein

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