KR20130031298A - Method for producing dope for optical film, method for producing optical film, optical film, polarizing plate, and liquid crystal display device - Google Patents

Abstract

In order to provide the manufacturing method of the dope for optical films which can manufacture the optical film excellent in transparency, heat resistance, moisture resistance, and workability, at least, the manufacturing method of the dope for optical films which has a resin particle, acrylic resin, and cellulose ester-type resin. A first mixing step of preparing a mixture by mixing a dispersion liquid of the resin particles and a surfactant, a resin composition of the acrylic resin and the cellulose ester resin in the range of 95: 5 to 30:70 by mass ratio, and a solvent And it has a 2nd mixing step which mixes the said mixture, The manufacturing method of the dope for optical films is used.

Description

Production method of dope for optical film, manufacturing method of optical film, optical film, polarizing plate and liquid crystal display device {METHOD FOR PRODUCING DOPE FOR OPTICAL FILM, METHOD FOR PRODUCING OPTICAL FILM, OPTICAL FILM, POLARIZING PLATE, AND LIQUID CRYSTAL DISPLAY DEVICE}

This invention is an optical film obtained by the manufacturing method of the dope for optical films, the optical film using the dope for optical films manufactured by the manufacturing method of the said dope for optical films, and the optical film obtained by the manufacturing method of the said optical film, the said optical It relates to a polarizing plate using a film as a transparent protective film and a liquid crystal display device provided with the polarizing plate.

Various optical films, for example, the transparent protective film for protecting the polarizing element of a polarizing plate, are arrange | positioned in the image display area of a liquid crystal display device. As such an optical film, the resin film excellent in transparency, such as a cellulose ester film, is used, for example.

In addition, the field of use of the liquid crystal display device is diversified, and the use of the liquid crystal display device is not only indoor, but also increased in the case of being used outdoors. Specifically, for example, by displaying an image or information on a liquid crystal display device, it functions as an advertisement medium instead of a poster or the like, that is, when used as a digital signage device or installed as a large display device in a street or a store. And the like may be used. In such a case, a liquid crystal display device may be used under high temperature, high humidity, etc., for example, and there existed a case where the deterioration by moisture absorption of an optical film becomes a problem. Then, as an optical film used, what has high moisture resistance which can suppress the deterioration by moisture absorption is calculated | required.

On the other hand, acrylic resins, such as polymethyl methacrylate resin (PMMA), which are known as optical materials with low hygroscopicity, have low hygroscopicity, are excellent in transparency and dimensional stability, and use as an optical film is being examined. However, the acrylic film containing acrylic resin had the property of being easy to crack and soft when compared with a cellulose ester film. For this reason, handling was difficult and it was difficult to manufacture the optical film for liquid crystal display devices which were large screen especially stable.

Moreover, as a resin film containing an acrylic resin, the thing of patent documents 1-3 is mentioned, for example.

Patent Document 1 describes an acrylic resin film-like article containing a multilayer structure polymer (acrylic particles) of an acrylic resin and a thermoplastic polymer (acrylic resin) having methacrylic acid alkyl ester as a main component.

In addition, Patent Document 2 describes a cellulose ester film containing an acrylic polymer and a cellulose ester.

In addition, Patent Document 3 describes an optical film containing an acrylic resin and a cellulose ester resin. And it is described in patent document 3 that you may contain acryl particle further in the said optical film.

Japanese Patent Application Publication No. 2005-163003 Japanese Patent Application Publication No. 2003-12859 International Publication No. 2009/47924

According to Patent Document 1, it is disclosed that an acrylic resin film-like article having a surface hardness or the like which can be used for vehicle use can be provided. However, only containing the resin particle in the acrylic resin did not solve the difficulty of handling as an optical film. For example, it was difficult to stably manufacture an optical film, for example, splitting when cutting the edge part of a film.

In addition, according to Patent Document 2, by containing a relatively low molecular weight acrylic resin instead of an additive such as a plasticizer, a film having better physical properties and the like can be produced while suppressing generation of precipitates or volatiles in the web during manufacture. It is disclosed that there is. As described above, the invention described in Patent Literature 2 enables the production of a film having better physical properties and the like while containing an acrylic polymer in the cellulose ester film while suppressing occurrence of precipitates or volatiles in the web during production. However, it was not made for the purpose of improving moisture resistance. Specifically, instead of additives such as plasticizers, a relatively low molecular weight acrylic resin was contained, and an acrylic polymer was not contained in order to increase moisture resistance. Therefore, the invention described in Patent Document 2 did not contain the acrylic polymer to such an extent that the moisture resistance was sufficiently enhanced.

Moreover, according to patent document 3, it is disclosed that the optical film which is low hygroscopicity, transparent, high heat resistance, and remarkably improved brittleness can be provided. Moreover, according to patent document 3, it is disclosed that the cutting property (cutting) of a film further improves by containing resin particle.

On the other hand, such an optical film is manufactured using the solution (dope) which melt | dissolved resin etc. which comprise a film in a solvent in many cases. Specifically, it is manufactured as a elongate resin film by the solution casting film forming method etc., for example. The solution casting film forming method specifically, peels from the support body the film obtained by casting the resin solution (dope) which melt | dissolved the transparency resin which is raw material resin in the solvent to the extent to which it is cast | flexible on the support which runs, and can peel. It is a method of manufacturing a long resin film by carrying out drying, extending | stretching, etc., conveying one film with a conveyance roller.

When the optical film containing acrylic resin, cellulose ester-type resin, and resin particle is manufactured by the manufacturing method using such dope, the optical film may not be manufactured suitably. Specifically, there were cases where the transparency, heat resistance, moisture resistance, and the like of the obtained optical film could not be sufficiently improved. Moreover, the workability of the obtained optical film might fall. Specifically, it is a case where the cutting property, such as a film split, falls, when cutting the edge part of a film after extending | stretching.

This invention is made | formed in view of such a situation, and an object of this invention is to provide the manufacturing method of the dope for optical films which can manufacture the optical film excellent in transparency, heat resistance, moisture resistance, and workability. Moreover, the manufacturing method of the optical film using the optical film dope manufactured by such a manufacturing method of the dope for optical films, the optical film obtained by the manufacturing method of the said optical film, the polarizing plate which used the said optical film as a transparent protective film, and It is an object to provide a liquid crystal display device provided with the polarizing plate.

MEANS TO SOLVE THE PROBLEM This inventor considered that generation | occurrence | production of the above problems is based on aggregation which arises in the dope, when manufacturing the dope for optical films. The aggregation which arises in this dope was inferred that the acryl particle is a thing by which the dispersibility of the said acryl particle falls by contacting directly with a cellulose-ester type resin. And when this aggregation generate | occur | produced, it was inferred that it was due to being unable to fully exhibit the property which each component has.

Therefore, as a result of various studies, the present inventors have come to the following invention which adjusted the timing of adding each component using surfactant.

The manufacturing method of the dope for optical films which concerns on one form of this invention is a manufacturing method of the dope for optical films which has at least a resin particle, acrylic resin, and a cellulose ester-type resin, The said resin particle and surfactant are mixed, and a mixture is prepared. It has a 1st mixing step to produce, the resin composition of the said acrylic resin and the said cellulose ester-type resin of the range of 95: 5-30: 70 by mass ratio, and the 2nd mixing step which mixes the said mixture, It is characterized by the above-mentioned.

According to such a structure, the manufacturing method of the dope for optical films which can manufacture the optical film excellent in transparency, heat resistance, moisture resistance, and workability can be provided. That is, dope for optical films which can manufacture the optical film excellent in transparency, heat resistance, moisture resistance, and workability is obtained by manufacturing an optical film using solution casting film forming methods.

This is inferred based on the following content.

It is thought that the surface of a resin particle is covered with surfactant by mixing beforehand the dispersion liquid of resin particle and surfactant. It is thought that the resin particle covered with this surfactant is less likely to cause a decrease in dispersibility due to contact of the cellulose ester resin. Therefore, even if it contains acrylic resin, cellulose ester-type resin, and resin particle, it is thought that the dope with high dispersibility of resin particle is obtained.

Acrylic resin and a cellulose ester are produced by containing such acrylic resin, cellulose ester resin, and resin particle, and using resin dope with high dispersibility of resin particle, for example, by producing a resin film by the solution casting film method etc. It is thought that what fully exhibited the property which each type | system | group resin and resin particle have was exhibited. Moreover, it is thought that the thing in which the resin particle was disperse | distributed uniformly to the whole surface of the obtained film is considered, and also from this point, it is thought that the thing where the property of the resin particle fully exhibited is obtained. Specifically, it is considered to exhibit sufficient moisture resistance, transparency and heat resistance of the acrylic resin, transparency, flexibility and processability of the cellulose ester-based resin, processability of the resin particles, and the like. Therefore, it is thought that the obtained dope for optical films is based on being able to manufacture the optical film excellent in transparency, heat resistance, moisture resistance, and workability.

From the above, according to the manufacturing method of the said structure, it is thought that the dope for optical films which can manufacture the optical film excellent in transparency, heat resistance, moisture resistance, and workability is used by using for the solution casting film forming method.

Moreover, in the manufacturing method of the dope for optical films of this invention, it is preferable to add a mixture in a mixing container before melt | dissolving in the solvent of the resin composition of acrylic resin and cellulose ester-type resin, or during melt | dissolution. According to such a structure, productivity can be improved. This is considered to be based on being able to disperse the resin particles mixed with the surfactant when dissolving the resin composition of the acrylic resin and the cellulose ester resin in a solvent. In addition, in this invention, a resin particle means the acrylic resin particle which does not melt | dissolve in the solvent of the resin composition of acrylic resin and the said cellulose ester-type resin.

Moreover, in the manufacturing method of the dope for optical films of this invention, it is preferable that surfactant is an ionic surfactant, and it is more preferable that it is an anionic surfactant. According to such a structure, the manufacturing method of the dope for optical films which can manufacture the optical film which is more excellent in transparency, heat resistance, moisture resistance, and workability can be provided. It is thought that this is because the surface of the resin particles can be appropriately covered with the surfactant by mixing the resin particles and the surfactant in advance.

 Moreover, in the manufacturing method of the dope for optical films of this invention, it is preferable that content of surfactant is 500 mass parts or less with respect to 100 mass parts of resin particles. According to such a structure, the manufacturing method of the dope for optical films which can manufacture the optical film which is more excellent in transparency, heat resistance, moisture resistance, and workability can be provided. It is thought that this is because the surface of the resin particles can be appropriately covered with the surfactant by mixing the resin particles and the surfactant in advance.

Moreover, in the manufacturing method of the dope for optical films of this invention, it is preferable to prepare acrylic resin and cellulose ester-type resin in a mixing container with a solvent so that it may become 95: 5-50: 50 by mass ratio, and mass ratio is It is more preferable to prepare so that it may be 80: 20-60: 40.

Moreover, the manufacturing method of the optical film of this invention is equipped with the casting | flow_spread process of forming a film by casting dope on the support body which runs, and the peeling process which peels a film from a support body, As a dope, it is for the optical film of this invention. It is characterized by using the dope for an optical film manufactured by the manufacturing method of dope. According to such a structure, the optical film excellent in transparency, heat resistance, moisture resistance, and workability can be manufactured.

Moreover, the optical film of this invention is obtained by the manufacturing method of the optical film of this invention, It is characterized by the above-mentioned. According to such a structure, the optical film excellent in transparency, heat resistance, moisture resistance, and workability is obtained. And since it is excellent in hygroscopicity, workability, etc., it can be easily applied also to the protective film of the polarizing plate for large screen liquid crystal display devices. Moreover, it can also be cut easily to a desired size.

The polarizing plate of the present invention is a polarizing plate comprising a polarizing element and a transparent protective film disposed on at least one surface of the polarizing element, wherein the transparent protective film is the optical film of the present invention. According to such a structure, since the optical film of this invention excellent in transparency, heat resistance, moisture resistance, and workability is applied as a transparent protective film of a polarizing plate, it is the polarizing plate which can be used suitably for a large screen liquid crystal display device, for example. Is obtained. Specifically, even if it is the polarizing plate for large screen liquid crystal display devices, distortion by moisture absorption etc. are suppressed. Moreover, since the optical film of this invention with favorable workability is used as a transparent protective film, generation | occurrence | production of a damage is suppressed even if a large film is used.

Moreover, the liquid crystal display device of this invention is a liquid crystal display device provided with a liquid crystal cell and two polarizing plates arrange | positioned so that a liquid crystal cell may be fitted, and at least one of two polarizing plates is a polarizing plate, It is characterized by the above-mentioned. According to such a structure, since the polarizing plate provided with the optical film of this invention excellent in transparency, heat resistance, moisture resistance, and workability is used, even if it is a large screen, it is the problem of the optical film of this invention arrange | positioned in an image display area. A liquid crystal display device with suppressed generation can be provided. Specifically, even if it is a large screen liquid crystal display device, generation | occurrence | production of the distortion by the moisture absorption of the optical film of this invention arrange | positioned in an image display area can be suppressed, for example. Moreover, since the processability of the optical film of this invention is favorable, even if it is a large film applied to the big screen liquid crystal display device, since the occurrence of the damage of the optical film of this invention is suppressed at the time of manufacture, the big screen liquid crystal display device Can be provided.

According to this invention, the manufacturing method of the dope for optical films which can manufacture the optical film excellent in transparency, heat resistance, moisture resistance, and workability can be provided. Moreover, the optical film obtained by the manufacturing method of the optical film using the dope for optical films manufactured by the manufacturing method of such dope for optical films, the optical film obtained by the manufacturing method of an optical film, the polarizing plate which used the optical film as a transparent protective film, and the said A liquid crystal display device having a polarizing plate is provided.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram which shows the structure of the manufacturing apparatus of the optical film by the solution casting film forming method.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment which concerns on the manufacturing method of the dope for optical films of this invention is described, this invention is not limited to these.

The manufacturing method of the optical film dope which concerns on this embodiment is a manufacturing method of the optical film dope which has a resin particle, acrylic resin, and a cellulose ester-type resin at least, mixes the dispersion liquid of a resin particle, and surfactant, It has a 1st mixing step to produce, acrylic resin of the range of 95: 5-30: 70 in mass ratio, the resin composition of the said cellulose ester-type resin, a solvent, and the 2nd mixing step which mixes a mixture, It is characterized by the above-mentioned. .

In addition, the optical film can be manufactured by the solution casting film forming method using the optical film dope (henceforth simply called "dope") manufactured by the manufacturing method of the dope for optical films of this invention. Can be.

By the manufacturing method of the dope for optical films of this invention, the method of manufacturing dope and manufacturing an optical film using this dope is optical by the so-called solution softening film method as shown in FIG. It is performed by the manufacturing apparatus of a film. In addition, the dope for optical films obtained by the manufacturing method of the dope for optical films of this invention is not only used for the solution casting film forming method, but can also be used for the other method of manufacturing an optical film.

FIG. 1: is schematic which shows the structure of the manufacturing apparatus 11 of the optical film using the manufacturing method of the dope for optical films of this invention. The manufacturing apparatus 11 of an optical film is equipped with the dope manufacturing apparatus 21, the dope filtration apparatus 22, and the film forming apparatus 23. As shown in FIG. The dope manufacturing apparatus 21 manufactures dope. The dope filtration apparatus 22 filters the produced dope. The film forming apparatus 23 manufactures an optical film using the filtered dope.

[Dope manufacturing apparatus]

The dope manufacturing apparatus 21 is equipped with the dope injection kiln 1, the discharge valve 6, the dope liquid feed pump 2, etc. as shown in FIG. The dope injection kiln 1 is a container for mixing dope with raw materials and solvents of optical films, such as resin and an additive. In addition, raw materials, such as resin, a solvent, and an additive, are mentioned later. In addition, the dope injection kiln 1 is connected to the piping 7 for flowing dope through the discharge valve 6 and sending liquid to another apparatus, for example, the dope filtration apparatus 22 etc. In addition, the piping 7 is connected to the casting die 13 of the film forming apparatus 23 via the dope filtration apparatus 22 etc., for example. And the piping 7 is equipped with the dope liquid pump 2 for enabling dope to distribute | circulate the inside of the piping 7 efficiently, just under the discharge valve 6, etc. The dope liquid pump 2 may be appropriately disposed not only directly under the discharge valve 6 but also for smoothly circulating the dope in the pipe 7.

Although the dope injection kiln 1 does not have a restriction | limiting in particular, It is preferable that the material thrown in can be heated to predetermined temperature, and can be stirred in the heated state. Specifically, the thing provided with a stirring blade, a heating apparatus, etc. are mentioned, for example. Although it does not specifically limit as a heating apparatus which heats the liquid in the dope injection kiln 1, It is preferable to carry out from the outside, for example, a jacket type thing is preferable from the point that temperature control is easy. In addition, when stirring the material thrown in the dope injection kiln 1 in the heated state, in order to suppress the loss of a solvent, it is preferable that the dope injection kiln 1 is a sealed container. In this case, as the dope injection kiln 1, it is preferable that it is a container which can endure predetermined pressure, specifically, the pressure more than the vapor pressure in the temperature at the time of stirring of a solvent. In addition, although pressurization in the dope injection kiln 1 may be performed by raising the vapor pressure of the solvent by the above-mentioned heating, you may use the method of pressurizing inert gas, such as nitrogen gas, etc., for example. In addition, you may arrange | position appropriate instruments, such as a pressure gauge, a thermometer, and a clay meter, in the dope injection kiln 1.

Next, the manufacturing method of the dope for optical films of this invention is demonstrated. Specifically, the manufacturing method of the dope by the dope manufacturing apparatus 21 is demonstrated, for example. In addition, the raw material of dope is mentioned later.

First, the dispersion liquid of resin particle and surfactant are mixed previously. In addition, this mixing is corresponded to a 1st mixing step. It does not specifically limit as a mixing method corresponding to this 1st mixing step. Specifically, what is necessary is just to be able to mix the dispersion liquid and surfactant of resin particle, you may mix in a solvent using a solvent, and you may mix, ie, powder-mix without using a solvent. Moreover, as the method, the method of mixing with the stirring blade provided in the dope injection kiln 1, the method of mixing using a mixer etc. separately, etc. are mentioned specifically ,. In addition, a well-known thing can be used as a mixer, For example, a Henschel mixer, a super mixer, a mechano mill, an agglom mill, a hybridization system, a cosmo system, etc. are mentioned.

Next, acrylic resin and cellulose-ester-type resin are thrown in together with a solvent, and it is accommodated in dope injection kiln 1 so that it may become 95: 5-30: 70 by mass ratio. And acrylic resin, cellulose ester-type resin, and a solvent are mixed in the dope injection kiln 1. Although it does not specifically limit as this mixing method, Specifically, the method of mixing by stirring with the stirring blade provided in the dope injection kiln 1 is mentioned, for example. By doing so, acrylic resin and cellulose ester-type resin melt | dissolve in a solvent gradually.

In that case, raw materials of dope other than acrylic resin, cellulose ester resin, and a solvent may be added before stirring, and may be added during stirring. That is, the timing to add the mixture (henceforth simply a mixture) obtained by mixing the dispersion liquid and surfactant of resin particle beforehand in the dope injection kiln 1 is not specifically limited. Specifically, for example, the mixture may be added before dissolving the acrylic resin and the cellulose ester resin in the solvent, or may be added during dissolution. After the acrylic resin and the cellulose ester resin are dissolved in the solvent, the mixture may be added to the resin solution and further mixed to disperse the mixture in the resin solution. That is, as an addition time of the dispersion liquid of a resin particle, what is necessary is just to add the dispersion liquid of a resin particle so that a resin particle may contact with an acrylic resin and a cellulose ester-type resin after contacting with surfactant.

The time for adding the mixture is not particularly limited as described above, but is preferably added before dissolving the acrylic resin and the cellulose ester resin in the solvent or during the dissolution. This is because the acrylic resin and the cellulose ester-based resin are dissolved in the solvent and the mixture can be dispersed in the solvent, thereby increasing productivity.

As mentioned above, a mixture is disperse | distributed to the resin solution which melt | dissolved acrylic resin and cellulose ester-type resin in the solvent, and the dope for optical films according to the manufacturing method of the dope for optical films of this invention is prepared. In addition, the viscosity of the dope in the dope injection kiln 1 can be measured using the clay system arrange | positioned at the dope injection kiln 1, for example, FVM-80A-EXHT by CBC Corporation.

The temperature of the dope in the dope injection kiln 1 is not particularly limited, but is also higher than the boiling point of the main solvent in the solvent, for example, a chlorine solvent, from the point of increasing the solubility of the acrylic resin and the cellulose ester resin. It is preferable that it is 20 degreeC-50 degreeC higher than the boiling point, and it is more preferable. When the temperature of the liquid at the time of this stirring is too low, the time required for dissolving acrylic resin and cellulose ester-type resin will prolong for a long time, and there exists a tendency for productivity of dope to fall. Moreover, when the temperature of the dope at the time of stirring is too high, the bubble which generate | occur | produced by the boiling of a solvent will remain easily in the obtained dope, and there exists a tendency for the foreign material by a bubble to generate easily in the obtained optical film. In addition, the temperature of the dope in the dope injection kiln 1 can be measured using the thermometer etc. which were arrange | positioned at the dope injection kiln 1. For example, you may measure the temperature of the liquid in the dope infusion kiln 1 using FVM-80A-EXHT by CBC Corporation as an example of the said clay system.

Moreover, as a capacity | capacitance of the dope injection kiln 1, it is preferable that it is 2m <3> -50m <3>, and it is more preferable that it is 5m <3> -20m <3>. If the capacity is too small, it may be necessary to increase the number of installations of the dope injection kiln or increase the number of treatments depending on the production amount of the dope. Moreover, when too big | large, the time required in order to melt | dissolve acrylic resin and cellulose ester-type resin in a solvent will prolong for a long time, and there exists a tendency for productivity of dope to fall.

The dope prepared by the dope injection kiln 1 is sent to the dope filtration apparatus 22 in the piping 7 connected to the dope injection kiln 1 by opening the discharge valve 6, and then forming into a film The apparatus 23, specifically, is fed to the casting die 13 of the film forming apparatus 23.

The raw material of the dope used for the manufacturing method of the dope for optical films of this invention is demonstrated.

(Acrylic resin)

Acrylic resin will not be specifically limited if it is resin which can exhibit transparency to the resin film obtained by shape | molding in film shape using the dope obtained by containing with cellulose ester-type resin. Specifically, it is acrylic resin which can be contained in a compatible state with cellulose ester-type resin in the obtained film, for example, and its high compatibility is preferable. By using a combination of highly compatible acrylic resins and cellulose ester-based resins, the properties of each resin can be supplemented with each other to achieve physical properties and quality required as an optical film. In addition, here, containing acrylic resin and cellulose ester-type resin in a compatible state means that it will be in the state which became compatible as a result by mixing each resin.

In addition, whether or not acrylic resin and cellulose ester resin are in a compatible state can be specifically determined by measuring the glass transition temperature Tg, for example. More specifically, it can judge from the following, for example. Even when the glass transition temperatures of both resins are different, when the compatibility of both resins is high, one glass transition temperature is measured. That is, the glass transition temperature inherent to each resin disappears, and it becomes one glass transition temperature and is measured. On the other hand, when the compatibility of both resins is low, since the glass transition temperature of each resin exists, the glass transition temperature of a mixture is measured more than two. In addition, the glass transition temperature here is the midpoint glass transition temperature measured by the temperature increase rate of 20 degree-C / min using a differential scanning calorimeter (DSC-7 type | mold by Perkin Elmer), and calculated | required according to JISK7121 (1987). It is set as (Tmg).

In addition, as acrylic resin, if it is acrylic resin as mentioned above, it will not specifically limit. Specifically, the resin etc. which were obtained by superposing | polymerizing the monomer containing acrylic monomers, such as methacrylic acid ester, such as acrylate ester and methyl methacrylate, are mentioned, for example. More specifically, methacryl resins, such as polymethyl methacrylate, etc. are mentioned, for example. Moreover, as a monomer, it is preferable to contain 50 mass%-99 mass% of methyl methacrylate, and 1 mass%-50 mass% of the other monomer copolymerizable with methyl methacrylate. Therefore, as acrylic resin, resin obtained by superposing | polymerizing the monomer containing 50 mass%-99 mass% of methyl methacrylate and 1 mass%-50 mass% of the other monomer copolymerizable with methyl methacrylate is preferable.

Although it does not specifically limit as another monomer copolymerizable with methyl methacrylate, For example, Alkyl methacrylate of C2-C18 of an alkyl group, Alkyl acrylate of C1-C18 of an alkyl group, Acrylic acid, Methacrylic acid Aromatic vinyl compounds, such as unsaturated group containing bivalent carboxylic acid, styrene, and (alpha) -methylstyrene, such as (alpha), (beta)-unsaturated acid, maleic acid, fumaric acid, and itaconic acid, such as (alpha), such as acrylonitrile and methacrylonitrile, (beta)-unsaturated nitrile, maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride, etc. are mentioned. In addition, these may be used independently and may be used in combination of 2 or more type. Moreover, among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethyl hexyl acrylate, etc. from a viewpoint of the thermal decomposition resistance and fluidity | liquidity of a copolymer are mentioned. Methyl acrylate and n-butyl acrylate are particularly preferable.

Moreover, what is marketed can also be used as acrylic resin. Specifically, for example, Delpet 60N manufactured by Asahi Kasei Chemical Co., Ltd., Delpet 80N manufactured by Asahi Kasei Chemical Co., Ltd., Diamond BR52 manufactured by Mitsubishi Rayon Co., Ltd., Mitsubishi Rayon Co., Ltd. Diamond BR80, Diamond BR83, manufactured by Mitsubishi Rayon, Inc., Diamond BR85, manufactured by Mitsubishi Rayon, Ltd., Diamond BR88, manufactured by Mitsubishi Rayon, Inc., KT75, manufactured by Denki Kagaku Kogyo Co., Ltd. Can be.

In addition, acrylic resin may be used by 1 type among the acrylic resin mentioned above, and may be used in combination of 2 or more type.

It is preferable that weight average molecular weights (Mw) are 110,000-1,000,000, and 150,000-400,000 especially from an viewpoint of the improvement of the embrittlement as the protective film for liquid crystal polarizing plates, and the transparency when it is compatible with a cellulose ester-type resin as acrylic resin. It is more preferable that is. In addition, a weight average molecular weight can be measured by gel permeation chromatography. As measurement conditions, the following conditions are mentioned, for example.

Solvent: Methylene Chloride

Column: Shodex K806, manufactured by Showa Denko Corporation, Shodex K805, manufactured by Showa Denko Corporation, and Shodex K803G, manufactured by Showa Denko Corporation, are used in connection.

Column temperature: 25 ℃

Sample concentration: 0.1 mass%

Detector: RI Model 504, manufactured by GEL Sciences

Pump: Hitachi Seisakushoze L6000

Flow rate: 1.0ml / min

Calibration curve: Calibration curve made by using 13 samples of standard polystyrene STK standard polystyrene (Mw = 2,800,000 to 500) manufactured by Tosoh Corp. (13 samples: suitable for use in which Mw is almost equally different)

As a manufacturing method of acrylic resin, if the above-mentioned acrylic resin is obtained, it will not specifically limit. Specifically, it can manufacture by polymerizing the monomer containing acrylic monomers, such as acrylic acid ester and methacrylic acid ester, as mentioned above by a well-known polymerization method, for example. Although it does not specifically limit as a polymerization method, For example, suspension polymerization, emulsion polymerization, block polymerization, solution polymerization, etc. are mentioned. Here, as a polymerization initiator used in a polymerization method, if a polymerization reaction can be started, it will not specifically limit, For example, a peroxide type polymerization initiator, an azo type polymerization initiator, a redox type polymerization initiator, etc. are mentioned. . In addition, as polymerization temperature in a polymerization method, if it is temperature which can advance a polymerization reaction, it will not specifically limit. Specifically, in the case of suspension polymerization or emulsion polymerization, it is preferable that they are 30 degreeC-100 degreeC, and in the case of block polymerization or solution polymerization, it is preferable that they are 80 degreeC-160 degreeC. Moreover, in order to control the reduced viscosity of the obtained copolymer, you may superpose | polymerize using alkyl mercaptan etc. as a chain transfer agent.

(Cellulose ester resin)

Cellulose ester-type resin will not be specifically limited if it is resin which can exhibit transparency to the resin film obtained by shape | molding in film shape using the dope obtained by containing with acrylic resin similarly to acrylic resin. Specifically, for example, from the viewpoints of improving brittleness and transparency when making it compatible with an acrylic resin, the total degree of substitution (T) of the acyl groups is 2 to 3 and the substitution of acyl groups having 3 to 7 carbon atoms. It is preferable that it is cellulose ester-type resin whose degree is 1.2-3. Moreover, it is more preferable that the substitution degree of a C3-C7 acyl group is 2-3. That is, as cellulose ester-type resin substituted by the C3-C7 acyl group, it is especially preferable that the substitution degree is 2-3. Moreover, as an acyl group, a propionyl group, a butyryl group, etc. are specifically mentioned, for example, A propionyl group is used preferably.

When the total substitution degree (T) of the acyl group of a cellulose ester-type resin is too low, ie, when the residue of the hydroxyl groups of 2nd, 3rd, 6th position of a cellulose ester molecule is too high, the compatibility of an acrylic resin will become inadequate, There exists a tendency for the haze of the obtained optical film to become high. When the substitution degree of the acyl group having 3 to 7 carbon atoms is too low even when the total degree of substitution (T) of the acyl group is high, the compatibility of the acrylic resin becomes insufficient or the brittleness of the obtained optical film tends to decrease . Specifically, even when the total substitution degree of the acyl group is 2 or more, for example, the degree of substitution of the acyl group having 2 carbon atoms, for example, the acetyl group is high, and the degree of substitution of the acyl group having 3 to 7 carbon atoms is 1.2. If it is less than, the compatibility decreases and the haze tends to increase. Moreover, even when the total substitution degree of an acyl group is 2 or more, when the substitution degree of the C8 or more acyl group is high and the substitution degree of the C3-C7 acyl group is less than 1.2, brittleness deteriorates and a desired characteristic is carried out. This tends not to be obtained.

As the cellulose ester-based resin, as described above, the total substitution degree (T) is 2 to 3 and the substitution degree of the acyl group having 3 to 7 carbon atoms is preferably 1.2 to 3, but the carbon number is 3 to 7 It is more preferable that the sum total of substitution degree of the other acyl group, ie, the acetyl group and the acyl group having 8 or more carbon atoms, is 1.3 or less.

Moreover, it is further more preferable that the total substitution degree (T) of the acyl group of cellulose ester-type resin exists in the range of 2.5-3.

The acyl group is not particularly limited, and may be an aliphatic acyl group or an aromatic acyl group. In the case of an aliphatic acyl group, it may be linear or may branch, and may have a substituent. In addition, carbon number of an acyl group contains carbon number of a substituent of an acyl group.

Moreover, when a cellulose ester-type resin has an aromatic acyl group as a substituent, it is preferable that the number of substituents X substituted by an aromatic ring is 0-5. Also in this case, the substitution degree of the acyl group having 3 to 7 carbon atoms and containing the carbon number of the substituent is preferably 1.2 to 3. For example, since a benzoyl group has 7 carbon atoms, when it has a substituent containing carbon, carbon number as a benzoyl group becomes 8 or more, and is not contained in the acyl group of 3-7 carbon atoms.

In addition, when the number of substituents substituted by an aromatic ring is two or more, they may mutually be same or different. In addition, condensed polycyclic compounds such as naphthalene, indene, indane, phenanthrene, quinoline, isoquinoline, chromen, chromman, phthalateazine, acridine, indole and indorin may be formed, for example.

In addition, as cellulose ester-type resin, if it is a cellulose ester-type resin as mentioned above, it will not specifically limit. Specifically, for example, cellulose acetate propionate resin, cellulose acetate butyrate resin, cellulose acetate benzoate resin, cellulose propionate resin, cellulose butyrate resin and the like are preferably used. That is, the cellulose ester-type resin which has an acyl group with 3 or 4 carbon atoms as a substituent is preferable. Among these, cellulose acetate propionate resin and cellulose propionate resin are especially preferable. In addition, the part which is not substituted by the acyl group exists normally as a hydroxyl group.

A cellulose ester-type resin can be synthesize | combined by a well-known method. In addition, substitution degree of an acetyl group and substitution degree of another acyl group are the values measured by the method according to the prescription | regulation of ASTM-D 817-96.

It is preferable that especially the weight average molecular weight (Mw) of a cellulose ester-type resin is 75000 or more from a viewpoint of the improvement of the compatibility and brittleness of an acrylic resin, It is more preferable that it is 75000-300000, It is still more preferable that it is 100000-240000, It is especially preferable that they are 160000-240000. When the weight average molecular weight (Mw) of cellulose ester-type resin is too small, there exists a tendency for the effect of improving heat resistance and brittleness not enough. In addition, you may use cellulose ester-type resin combining 2 or more types of cellulose ester-type resins. In addition, the weight average molecular weight (Mw) of cellulose ester-type resin can be measured similarly to acrylic resin.

The content ratio of the acrylic resin to the cellulose ester resin is 95: 5 to 30:70 by mass, more preferably 95: 5 to 50:50, and further preferably 90:10 to 60:40. When content of acrylic resin increases too much with respect to the said cellulose ester-type resin, there exists a tendency which cannot fully exhibit the effect by a cellulose ester-type resin. Moreover, when content of acrylic resin becomes too small with respect to the said cellulose ester-type resin, the effect by acrylic resin cannot fully be exhibited, for example, there exists a tendency for the moisture resistance of the obtained optical film etc. to become inadequate.

(Resin particles)

Unlike acrylic resin, a resin particle will not be specifically limited if it is a thing which does not melt | dissolve in the solvent of acrylic resin and a cellulose ester-type resin. Specifically, it is preferable that it is the acrylic resin particle which exists in the state of particle | grains, ie, incompatible state, in the optical film containing acrylic resin and cellulose ester-type resin in a compatible state, for example. More specifically, for example, the volume average particle | grains of an acryl particle | grain are taken out the solution which obtained the predetermined amount of the obtained optical film, stirred in the solvent of acrylic resin and cellulose ester-type resin, and melt | dissolved the component melt | dissolved in a solvent sufficiently. It is preferable to filter using the membrane filter made from PTFE which has a pore diameter of less than a diameter, and it is preferable that the weight of the insoluble matter collected by filtration is 90 mass% or more of the acrylic resin particle added to the optical film.

The resin particles are not particularly limited as long as they are the resin particles as described above. Specifically, it is preferable that it is a resin particle in which two or more layer structures were formed, for example, and it is preferable that it is a multilayered structure acrylic resin granular composite_body | complex especially mentioned later.

The multilayer structure acrylic resin granular composite material is a particulate acrylic resin polymer having a structure in which an innermost hard layer polymer, a crosslinked soft layer polymer exhibiting rubber elasticity, and an outermost hard layer polymer are stacked in a layer shape from the center portion to the outer peripheral portion. That is, a multilayered acrylic resin granular composite is a multilayered acrylic resin granular composite composed of the innermost hard layer, the crosslinked soft layer and the outermost hard layer from the center portion to the outer peripheral portion. Such a multilayered acrylic resin granular composite having a three-layer core shell structure is preferably used.

The following are mentioned as a preferable aspect of a multilayer structure acrylic resin granular composite_body | complex. That is, what has each layer provided as follows is mentioned.

Examples of the innermost hard layer polymer include, for example, 80% by mass to 98.9% by mass of methyl methacrylate, 1% by mass to 20% by mass of an alkyl acrylate having an alkyl group of 1 to 8 carbon atoms, and 0.01% And 0.3% by mass of a mixture of monomers.

Moreover, as a crosslinked soft layer polymer, For example, in the presence of an innermost hard layer polymer, 75 mass%-98.5 mass% of alkylacrylates of 4-8 carbon atoms of an alkyl group, 0.01 mass%-5 mass% of a multifunctional crosslinking agent, And what is obtained by superposing | polymerizing the mixture of the monomer which consists of 0.5 mass%-5 mass% of polyfunctional grafting agents, etc. are mentioned.

As the outermost hard layer polymer, for example, in the presence of a polymer composed of an innermost hard layer and a crosslinked soft layer, 80% by mass to 99% by mass of methyl methacrylate, and an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group. The thing obtained by superposing | polymerizing the mixture of the monomer which consists of 1 mass%-20 mass%, etc. are mentioned.

And the content rate of each layer is a multilayer structure acrylic type whose innermost hard layer polymer is 5 mass%-40 mass%, a soft layer polymer 30 mass%-60 mass%, and an outermost hard layer polymer is 20 mass%-50 mass%. Granular composites are preferred. Moreover, when fractionated with acetone, there is an insoluble part, and the multilayer structure acrylic granular composite whose methyl ethyl ketone swelling degree of the insoluble part is 1.5-4 is more preferable.

In addition, as disclosed in Japanese Patent Application Laid-Open No. 60-17406 or Japanese Patent Application Laid-Open No. 3-39095, not only the composition and particle diameter of each layer of the multilayer structure acrylic granular composite were defined, but also the multilayer structure. By setting the tensile modulus of elasticity of the acrylic granular composite and the methyl ethyl ketone swelling degree of the acetone insoluble portion within a specific range, it is possible to realize a more sufficient balance of impact resistance and stress whitening resistance.

As the innermost hard layer polymer, for example, 80% by mass to 98.9% by mass of methyl methacrylate, 1% by mass to 20% by mass of alkyl acrylate having 1 to 8 carbon atoms of the alkyl group, and 0.01% by mass to polyfunctional grafting agent It is more preferable that it is obtained by superposing | polymerizing the mixture of the monomer which consists of 0.3 mass%. Here, as the alkyl acrylate having 1 to 8 carbon atoms of the alkyl group, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethyl hexyl acryl The rate etc. are mentioned, Methyl acrylate and n-butyl acrylate are used preferably.

Moreover, when the content rate of the said alkyl acrylate in an innermost hard layer polymer is too low, there exists a tendency for the thermal decomposition property of the obtained innermost hard layer polymer to become large. Moreover, when the content rate of the said alkyl acrylate is too high, the glass transition temperature of an innermost hard layer polymer will become low, and there exists a tendency for the impact resistance imparting effect of a three-layer structure acrylic granular composite_body | complex to fall.

Moreover, as a polyfunctional graft agent, the polyfunctional monomer which has another polymerizable functional group, for example, allyl ester of acrylic acid, methacrylic acid, maleic acid, and fumaric acid, etc. are mentioned, Allyl methacrylate is used preferably. The polyfunctional graft agent is used to chemically bond the innermost hard layer polymer and soft layer polymer. As a compounding ratio of the polyfunctional graft agent at the time of innermost hard layer superposition | polymerization, it is preferable that they are 0.01 mass%-0.3 mass%, for example.

As the crosslinked soft layer polymer, for example, in the presence of the innermost hard layer polymer, 75 to 98.5 mass% of alkyl acrylate having 1 to 8 carbon atoms of an alkyl group, 0.01 to 5 mass% of a polyfunctional crosslinking agent, and a multi-tube It is preferable to obtain by superposing | polymerizing the mixture of the monomer which consists of 0.5 mass%-5 mass% of a functional graft agent.

Here, as the alkyl acrylate having 4 to 8 carbon atoms in the alkyl group, n-butyl acrylate and 2-ethylhexyl acrylate are preferably used.

Moreover, it is also possible to copolymerize 25 mass% or less of copolymerizable other monofunctional monomer with these polymerizable monomers.

Other monofunctional monomers copolymerizable include styrene and substituted styrene derivatives. The ratio of alkyl acrylate having 4 to 8 carbon atoms and styrene of the alkyl group is that the more electrons, the lower the glass transition temperature of the crosslinked soft layer polymer, that is, the softening is possible.

On the other hand, it is advantageous from the viewpoint of the transparency of the resin tank organism to bring the refractive index at room temperature of the soft layer polymer closer to the innermost hard layer polymer, the outermost hard layer polymer, and the acrylic resin, and in consideration of these, the ratio of both is selected. do.

As a polyfunctional graft agent here, the thing similar to the polyfunctional graft agent used when manufacturing an innermost layer hard polymer is mentioned. The polyfunctional graft agent used here is used in order to chemically bond a soft layer polymer and an outermost hard layer polymer. It is preferable that the compounding ratio of the polyfunctional graft agent used at the time of the innermost hard layer superposition | polymerization is 0.5 mass%-5 mass% from a viewpoint of an impact resistance imparting effect.

As a polyfunctional crosslinking agent, although generally known crosslinking agents, such as a divinyl compound, a diaryl compound, a diacryl compound, a dimethacryl compound, can be used, polyethyleneglycol diacrylate (molecular weight 200-600) is used preferably.

The polyfunctional crosslinking agent used here is used in order to produce a crosslinked structure at the time of superposition | polymerization of a crosslinked soft layer polymer, and to express the effect of imparting impact resistance. However, when the above-mentioned multifunctional grafting agent is used at the time of superposition | polymerization of a crosslinked soft layer polymer, since it produces the crosslinked structure of a crosslinked soft layer polymer to some extent, a polyfunctional crosslinking agent is not an essential component. When using a polyfunctional crosslinking agent, it is preferable that the compounding ratio of the polyfunctional crosslinking agent used at the time of superposition | polymerization of a crosslinked soft layer polymer is 0.01 mass%-5 mass% from a viewpoint of impact resistance provision effect.

The outermost hard layer polymer is composed of 80% by mass to 99% by mass of methyl methacrylate and 1% by mass to 20% by mass of alkyl acrylate having 1 to 8 carbon atoms in the presence of the innermost hard layer polymer and the soft layer polymer. It is preferable to obtain by superposing | polymerizing the mixture of monomers.

As an acryl alkylate, although the above-mentioned thing is used, methyl acrylate and ethyl acrylate are used preferably. As for the ratio of the alkylacrylate unit in an outermost hard layer polymer, 1-20 mass% is preferable.

In addition, in the case of superposition | polymerization of an outermost hard layer polymer, in order to improve compatibility with an acrylic resin, in order to adjust molecular weight, it is also possible to carry out using alkyl mercaptan etc. as a chain transfer agent.

In particular, it is preferable to provide a gradient in which the molecular weight gradually decreases from the inside to the outside in the outermost hard layer in improving the balance between elongation and impact resistance. As a specific method, the molecular weight of the polymer which forms an outermost hard layer is multi-layered by the method of dividing the mixture of monomers for forming an outermost hard layer into two or more, and increasing the chain transfer agent added each time one by one. It is possible to make it small toward the outer side from the inside of an acryl-type granular composite_body | complex.

The molecular weight formed at this time can also be investigated by polymerizing the mixture of the monomer used for each time on the same conditions independently, and measuring the molecular weight of the obtained polymer.

In the multilayer structure acrylic granular composite, the mass ratio of the core and the shell is not particularly limited. Specifically, for example, when the entire multilayer structure acrylic granular composite is 100 parts by mass, the core layer is preferably 50 parts by mass or more and 90 parts by mass or less, and more preferably 60 parts by mass or more and 80 parts by mass or less. In addition, a core layer here is an innermost hard layer.

As an example of the commercial item of such a multilayer-structure acryl-type granular composite, For example, Mitsubishi Rayon Co., Ltd. metabrene, Kaneka-Kane Co., Ltd. Pallaroid, Kalha KK Kaherha Co., Ltd. And acryloids manufactured by Andrew Haas, starfiloids manufactured by Kantsu Kasei Co., Ltd., and parapet SA manufactured by Kuraray Co., Ltd. These may be used independently and may be used in combination of 2 or more type.

In addition, graft copolymer particles are also suitably used as the acrylic resin particles of the resin particles. The graft copolymer particles are specifically, for example, unsaturated carboxylic acid monomers, unsaturated carboxylic acid monomers, aromatic vinyl monomers, and other vinyl copolymerizable with these, if necessary, in the presence of a rubbery polymer. Graft copolymer particles and the like obtained by copolymerizing a mixture of monomers containing a system monomer.

Specifically as a rubbery polymer, the particle | grains containing diene rubber, acrylic rubber, ethylene rubber, etc. are mentioned, for example. More specifically, for example, polybutadiene, styrene-butadiene copolymer, block copolymer of styrene-butadiene, acrylonitrile-butadiene copolymer, butyl-butadiene copolymer acrylate, polyisoprene, butadiene-methylmethacrylate Copolymers, butyl-methyl methacrylate copolymers, butadiene-ethyl acrylate copolymers, ethylene-propylene copolymers, ethylene-propylene-diene-based copolymers, ethylene-isoprene copolymers, ethylene-methyl acrylate copolymers, and the like. The particle | grains etc. which are mentioned are mentioned. These rubbery polymers may be used independently and may be used in combination of 2 or more type.

Moreover, what is marketed can also be used as acryl particle | grains. Specifically, for example, Mitsubishi Rayon Co., Ltd. metabrene W-341, Soken Kagaku Co., Ltd. Chemisuno MR-2G, Soken Kagaku Co., Ltd. Chemisuno MS-300X, etc. Can be mentioned.

In addition, it does not specifically limit about content of resin particle. Specifically, it is preferable that it is 0.5 mass%-30 mass% with respect to the gross mass of resin which comprises an optical film, for example, and it is more preferable that it is 1 mass%-15 mass%.

The particle diameter of the resin particles is not particularly limited. Specifically, for example, it is preferably 10 nm or more and 1000 nm or less, more preferably 20 nm or more and 500 nm or less, and even more preferably 50 nm or more and 400 nm or less.

Moreover, it is preferable that the refractive index of resin particle is close to the refractive index of acrylic resin, and the refractive index of the mixture of acrylic resin and cellulose ester-type resin from the point of obtaining a film with high transparency. Specifically, for example, the difference in refractive index between the resin particles and the acrylic resin is preferably 0.05 or less, more preferably 0.02 or less, and even more preferably 0.01 or less.

In order to satisfy the conditions of the above-mentioned refractive index, the method of adjusting each monomer unit composition ratio of acrylic resin, the method of adjusting the composition ratio of the rubbery polymer or monomer used for an acrylic particle, etc. are mentioned. By doing so, a refractive index difference can be made small and the protective film for liquid crystal polarizing plates excellent in transparency can be obtained.

In addition, the refractive index difference here is made to melt | dissolve the protective film for liquid crystal polarizing plates which concerns on this invention fully in suitable solvent in a solvent in which an acrylic resin is soluble, and to make it a cloudy solution. It isolate | separates into a part and refine | purifies this soluble part (acrylic resin) and an insoluble part (resin particle), respectively, and shows the difference of the measured refractive index (23 degreeC, measurement wavelength: 550 nm).

(Surfactants)

It does not specifically limit as surfactant, Specifically, For example, cationic surfactant (cationic surfactant), anionic surfactant (anionic surfactant), an amphoteric surfactant (nonionic surfactant), etc. Any of a nonionic surfactant such as an ionic surfactant and a fluorine-based surfactant can be used. Of these, ionic surfactants are preferred, and anionic surfactants are more preferred.

Specific examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzetonium chloride, pyridinium salts, imidazolinium salt alkylamine oxides, and polyamine derivatives. .

Examples of the anionic surfactants include higher alcohol (C8 to C22) sulfate ester salts, aliphatic alcohol phosphate ester salts, alkyl aryl sulfonates, sulfonates of alkyl amides, and sulfonates of dibasic fatty acid esters.

Specific examples of the higher alcohol (C8 to C22) sulfate ester salts include, for example, sodium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, Teepol-81 manufactured by Shell Chemical Co., Ltd. 2nd sodium alkyl sulfate etc. are mentioned.

Specifically as aliphatic alcohol phosphate ester salt, the sodium salt of a cetyl alcohol phosphate ester, etc. are mentioned, for example.

Specific examples of the alkyl aryl sulfonates include sodium salts of dodecyl benzene sulfonic acid, sodium salts of isopropyl naphthalene sulfonic acid, sodium salts of dinaphthalene disulfonic acid, sodium salts of metanitrobenzene sulfonic acid, and the like. .

Specific examples of the sulfonates of alkyl amides include C ₁₇ H ₃₃ CON (CH ₃ ) CH ₂ SO ₃ Na and the like.

Specific examples of the sulfonates of the dibasic fatty acid esters include sodium sulfo succinic acid dioctyl ester and sodium sulfo succinic acid dihexyl ester.

Specifically as an amphoteric surfactant, a carboxy betaine type amphoteric surfactant, a sulfo betaine type amphoteric surfactant, an aminocarboxylic acid salt, imidazolinium betaine, laurylamide propyl betaine, lauryl amino acetic acid, for example. Betaine and the like.

Specific examples of the fluorine-based surfactants include perfluoro alkyl sulfonates, perfluoro alkyl carboxylates, perfluoro alkyl ethylene oxide adducts, perfluoro alkyl trimethyl ammonium salts, and perfluoro alkyl groups. A hydrophilic group containing oligomer, a perfluoro alkyl quinyl group containing oligomer perfluoro alkyl group containing urethane, etc. are mentioned.

Moreover, a commercial item can also be used as surfactant. Specifically, examples of the anionic surfactants include Electrode S-412-2 manufactured by Takemoto Yushi Co., Ltd., Electro Stripper F manufactured by Kao Corporation. Moreover, as cationic surfactant, Elegance 264WAX by Nichiyu Corp., the Elect S S-531 by Takemoto Yushi Co., Ltd., etc. are mentioned, for example. Moreover, as a nonionic surfactant, Rickettal S-100 by Rikenvitamin Corporation, etc. are mentioned, for example.

Although it changes also with surfactant etc. as content of surfactant, Specifically, it is preferable that it is 500 mass parts or less with respect to 100 mass parts of said acrylic particles, for example, It is more preferable that it is 1 mass part-500 mass parts It is more preferable that they are 10 mass parts-500 mass parts. When there are too few surfactant, there exists a tendency which cannot fully exhibit the effect by surfactant. Moreover, when there are too many surfactant, surfactant will precipitate from the obtained optical film, the hygroscopicity of an optical film will become high, and there exists a tendency for the undesirable quality to express in the quality of an optical film.

(additive)

In addition, you may mix | blend various additives with dope for optical films suitably in order to adjust the chemical characteristic, a mechanical characteristic, an electrical characteristic, etc. of the optical film obtained using the dope for optical films. As an additive, a plasticizer, antioxidant, an ultraviolet absorber, etc. are mentioned, for example.

Although it does not specifically limit as a plasticizer, What is added in order to provide suitable softness to the obtained optical film is mentioned. Specifically, for example, an ester plasticizer, a phosphate ester plasticizer, a phthalic ester plasticizer, a trimellitic acid ester plasticizer, a pyromellitic acid plasticizer, a glycolic acid ester plasticizer, a citric acid ester plasticizer and the glycol plasticizer Etc. can be mentioned.

Specific examples of the ester plasticizer include those formed of polyhydric base acids such as aliphatic dibasic acids, alicyclic dibasic acids and aromatic dibasic acids, and polyhydric alcohols such as glycols. Moreover, as aliphatic dibasic acid, although it can use without a restriction | limiting in particular, Specifically, adipic acid, sebacic acid, phthalic acid, terephthalic acid, 1, 4- cyclohexyl dicarboxylic acid, etc. are mentioned.

Specifically as a phosphoric acid ester plasticizer, a triphenyl phosphate, a tricyclyl phosphate, a cledil diphenyl phosphate, an octyl diphenyl phosphate, a diphenyl biphenyl phosphate, a trioctyl phosphate, a tributyl phosphate, etc. are mentioned, for example. have.

Specific examples of the phthalic ester plasticizer include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, and butyl benzyl phthalate. .

Specific examples of trimellitic acid-based plasticizers include tributyltrimerate, triphenyltrimerate, triethyltrimerate, and the like.

Specific examples of pyromellitic acid ester plasticizers include tetrabutyl pyromellitate, tetraphenyl pyromellitate, tetraethyl pyromellitate and the like.

Specific examples of the glycolic acid ester plasticizer include triacetin, tributylin, ethylphthalylethylglycolate, methylphthalylethylglycolate, butylphthalylbutylglycolate, and the like.

As a citric acid ester plasticizer, specifically, for example, triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tri- n-butyl citrate, acetyl tri-n- (2- Ethylhexyl) citrate, and the like.

Examples of the glycol plasticizer include ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, and 1,2- Butylene glycol, and the like.

A plasticizer may be used individually by said each plasticizer, and may be used in combination of 2 or more type.

Although it does not specifically limit as antioxidant, For example, a hindered phenol type compound is used preferably. Specifically, for example, 2,6-di-t-butyl-p-cresol and pentaerythryl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) prop Cypionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxy phenyl) propionate], 1,6-hexanediol-bis [3- (3,5- Di-t-butyl-4-hydroxy phenyl) propionate], 2,4-bis- (n-octyl thio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, 2,2-thio-diethylene bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- ( 3,5-di-t-butyl-4-hydroxy phenyl) propionate, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamid), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxy benzyl) benzene, tris- (3,5-di-t-butyl-4-hydrate Roxy benzyl) -isocyanurate etc. are mentioned. In particular, 2,6-di-t-butyl-p-cresol, pentaerythryl-tetrakis [3- (3,5-di-t-butyl-4-hydroxy phenyl) propionate], triethylene Glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] and the like. For example, N, N'-bis [3- (3,5-di-t-butyl-4-hydroxy phenyl) propionyl] hydrazine type metal deactivator and tris (2,4- You may use together phosphorus process stabilizers, such as di-t- butyl phenyl) phosphite.

The optical film manufactured using the dope obtained by the manufacturing method of the dope for optical films of this invention can be used for the protective film for polarizing plates, etc. In this case, a ultraviolet absorber is used for the prevention of deterioration, such as a polarizing plate or a liquid crystal. It is preferably used.

As a ultraviolet absorber, the thing excellent in the absorptivity of the ultraviolet-ray of wavelength 370nm or less, and the absorption of visible light of wavelength 400nm or more from a viewpoint of favorable liquid crystal display property is used preferably. It is preferable that the transmittance | permeability of 380 nm specifically is less than 10%, and it is more preferable that it is especially less than 5%.

Specifically as a ultraviolet absorber, For example, an oxy benzophenone type compound, a benzotriazole type compound (benzotriazole type ultraviolet absorber), a salicylic acid ester type compound, a benzophenone type compound (benzophenone type ultraviolet absorber), cyanoacryl A latex compound, a nickel complex salt compound, a triazine compound, etc. are mentioned.

In said ultraviolet absorber, a benzotriazole type ultraviolet absorber and a benzophenone type ultraviolet absorber are preferable. Although the specific example of a benzotriazole type ultraviolet absorber and a benzophenone type ultraviolet absorber is given to the following, this invention is not limited to these.

Specifically as a benzotriazole type ultraviolet absorber, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-, for example tert-butyl phenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di -tert-butyl phenyl) -5-chloro benzotriazole, 2- (2'-hydroxy-3 '-(3 ", 4", 5 ", 6" -tetrahydrodophthalimidemethyl) -5' -Methylphenyl) benzotriazole, 2,2-methylene bis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2 ′ -Hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chloro benzotriazole, 2- (2H-benzotriazol-2-yl) -6- (straight and branched dodecyl) -4 -Methyl phenol (TINUVIN171, made by BASF Japan Co., Ltd.), octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H-benzotriazol-2-yl) phenyl] propionate And 2-ethylhexyl-3- [3-tert-butyl-4- And mixtures of hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate (TINUVIN109, manufactured by BASF Japan Co., Ltd.) and the like.

Specifically as a benzophenone type ultraviolet absorber, 2, 4- dihydroxy benzophenone, 2, 2'- dihydroxy-4- methoxy benzophenone, 2-hydroxy-4- methoxy, for example. -5-sulfo benzophenone, bis (2-methoxy-4-hydroxy-5- benzoyl phenylmethane), etc. are mentioned.

(menstruum)

The solvent used for the manufacturing method of the dope for optical films of this invention will not be specifically limited if it is a solvent in which acrylic resin and cellulose ester-type resin can be dissolved. Specific examples of the solvent include chlorine-based organic solvents such as methylene chloride, and organic solvents such as methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, 2-propanol, 1,1,1,3,3-tetrafluoropropane, 1,1,3,3-tetrafluoropropane, 1,1,1,3,3-pentafluoropropane, 3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro- Non-chlorinated organic solvents such as 1-propanol and nitroethane, and the like. Among these, methylene chloride, methyl acetate, ethyl acetate, acetone, and the like are preferable.

In addition, it is preferable that the solvent contains a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. As content, it is preferable that they are 1 mass%-40 mass% with respect to the whole solvent. When the content ratio of the alcohol in the dope increases, the web gels, the peeling from the metal support becomes easy, and when the content ratio of alcohol is low, dissolution of the acrylic resin and the cellulose ester resin in the non-chlorinated organic solvent system. Has a role to promote.

In addition, three kinds of the mixture which previously mixed the acrylic resin, the cellulose ester resin, the dispersion liquid of the acrylic particles, and the surfactant with a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms It is preferable that it is the dope composition which melt | dissolved at least 15 mass%-45 mass% in total.

Moreover, as a linear or branched aliphatic alcohol of 1-4 carbon atoms, methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol, etc. are mentioned, for example. have. Among these, ethanol is preferable for reasons such as high dope stability, relatively low boiling point and good dryness.

(Dope filter)

The dope filtration apparatus 22 is equipped with the dope stationary kiln 3, the 1st filter 4, the 2nd filter 5, the dope liquid feed pump 2, etc. as shown in FIG. When the dope manufactured by the dope manufacturing apparatus 21 hardly generate | occur | produces undissolved matter, a precipitate, etc., it is not necessary to provide the dope filtration apparatus 22, In order to reduce the foreign material generation in the optical film obtained, It is preferable to provide the dope filtration apparatus 22.

The dope stationary kiln 3 is a container for storing dope once. In addition, the viscosity of the dope prepared in the dope in the dope stationary kiln 3, for example, the dope injection kiln 1, and sending it to the film forming apparatus 23, the clay system arrange | positioned at the dope stationary kiln 3 For example, it can measure using FVM-80A-EXHT by CBC Corporation. Here, the viscosity of dope shows the viscosity in 35 degreeC. The first filter 4 and the second filter 5 are filters for filtering undissolved products or precipitates from the dope stored in the dope stationary kiln 3. And the filtration apparatus 22 is equipped with the 1st filter 4 and the 2nd filter 5, and is arrange | positioned in series, respectively. As shown in FIG. 1, the filter with which the dope filtration apparatus 22 is equipped is three or more types, even if it connects two or more types of filters of the 1st filter 4 and the 2nd filter 5 in series. May be connected in series, or may be the case of using 1 type independently. In addition, the material of the filter medium used for the 1st filter 4 and the 2nd filter 5 with which the dope filtration apparatus 22 is equipped does not have a restriction | limiting in particular, A normal filter medium can be used. For example, a filter medium made of plastic such as polypropylene, a filter paper made of cellulose or rayon, and a metal filter medium such as stainless steel are preferable because there is no dropout of fibers. It is preferable from the point which removes and reduces the impurities contained in the solution of resin of a raw material, especially a bright point foreign material by filtration. 0.03 mm or less is preferable and, as for filtration precision, 0.001 mm-0.015 mm are more preferable. In addition, when using a some filter as mentioned above, it is preferable to provide one filter of 0.002 mm-0.005 mm.

And the dope liquid pump 2 smoothly supplies the dope in the piping 7 to the piping 7 etc. which connect the dope stationary kiln 3, the 1st filter 4, and the 2nd filter 5, and the like. In order to do this, you may arrange | position appropriately. In particular, immediately before the first filter 4 and the second filter 5, in order to increase the filtration pressure, it is preferable that the dope liquid pump 2 is disposed.

Therefore, after the dope prepared by the dope manufacturing apparatus 21 is filtered by the dope filtration apparatus 22, it is sent to the film forming apparatus 23, specifically, the casting die 13 of the film forming apparatus 23.

(Film forming device)

As shown in FIG. 1, the film forming apparatus 23 includes the endless belt support 12, the flexible die 13, the peeling roller 14, the stretching apparatus 15, the drying apparatus 17, and the winding apparatus 18. ) And the like. The flexible die 13 allows the dope 19 to be flexible on the surface of the endless belt support 12. The endless belt support 12 forms a web made of the dope 19 cast from the casting die 13, and is dried while conveying to form a film. The peeling roller 14 peels a film from the endless belt support 12. The stretching apparatus 15 stretches the peeled film. The drying apparatus 17 is made to dry, conveying the stretched film with a conveyance roller. The winding device 18 winds up the dry film in roll shape, and makes it a film roll.

Here, as the dope 19, the dope prepared by the dope manufacturing apparatus 21, the dope filtered by the dope filtration apparatus 22, and conveyed to the film forming apparatus 23 are used as needed.

As shown in FIG. 1, the dope 19 is supplied from the piping 7 connected to the upper end of the casting die 13. Then, the supplied dope is discharged from the flexible die 13 to the endless belt support 12, and a flexible film (web) is formed on the endless belt support 12.

As shown in FIG. 1, the endless belt support 12 is an endless belt support made of metal running on an infinite surface having a mirror surface. As an endless belt support body, the endless belt support body which consists of stainless steel etc. is used preferably from the peelable point of a film. Although the width | variety of the flexible film | membrane (web) cast by the casting die 13 is not specifically limited, From the viewpoint of using the width | variety of the endless belt support 12 effectively, it is 80 with respect to the width of the endless belt support 12. It is preferable to set it as% to 99%. And in order to finally obtain the optical film of 1000-4000 mm in width, it is preferable that the width | variety of the endless belt support body 12 is 1500 mm or more. Instead of the endless belt support, a rotating metal drum (endless drum support) having a mirror surface may be used.

And the said endless belt support body 12 dries the solvent in a casting film (web), conveying the casting film (web) formed on the surface. The drying is performed, for example, by heating the endless belt support 12 or by spraying heating air onto the cast film (web). In that case, although the temperature of a flexible film (web) changes also with kinds of dope, in consideration of the conveyance speed, productivity, etc. with the evaporation time of a solvent, the range of -5 degreeC-70 degreeC is preferable, and 0 degreeC- The range of 60 degreeC is more preferable. The higher the temperature of the cast film (web), the faster the drying rate of the solvent is preferable. However, if the temperature is too high, foaming or deterioration of planarity tends to occur.

When the endless belt support 12 is heated, for example, a method of heating the flexible film (web) on the endless belt support 12 with an infrared heater, and a method of heating the back surface of the endless belt support 12 with an infrared heater. The method of spraying heating air on the back surface of the endless belt support 12, etc. are mentioned, It is possible to select suitably as needed.

In addition, when spraying a heating wind, it is preferable that the wind pressure of the heating wind is 50 Pa-5000 Pa in consideration of the uniformity of solvent evaporation. The temperature of the heating wind may be dried at a constant temperature, or may be supplied by dividing the temperature by several stages in the traveling direction of the endless belt support 12.

After the dope is cast on the endless belt support 12 and the flexible film (web) is formed, the time from the endless belt support 12 until the solvent is removed from the flexible film (web) and the formed film is peeled off Although it changes also with the film thickness of the optical film to manufacture and the solvent to be used, it is preferable that it is the range for 0.5 to 5 minutes in consideration of the peelability from the endless belt support 12.

Although the traveling speed of the endless belt support 12 is not specifically limited, From a viewpoint of productivity etc., it is preferable that it is about 50 m / min-about 200 m / min, for example. Moreover, it is preferable that ratio (draft ratio) of the traveling speed of the endless belt support body 12 with respect to the flow velocity of the dope discharged from the casting die 13 is about 0.8-2. If the draft ratio is within this range, a flexible film (web) can be formed stably. For example, when a draft ratio is too big | large, it exists in the tendency to generate | occur | produce the phenomenon called neck in which a flexible film (web) shrinks in the width direction, and it becomes impossible to form a wide film.

The peeling roller 14 is arrange | positioned in the vicinity of the surface of the side by which the dope 19 of the endless belt support 12 is flexible, and the distance of the endless belt support 12 and the peeling roller 14 is 1 mm-100 mm. Is preferably. Using the peeling roller 14 as a support point, the formed film is peeled off by tensioning and pulling out the film formed by removing a solvent from a casting film (web). When peeling a film from the endless belt support body 12, a film is extended | stretched to the conveyance direction (Machine Direction: MD direction) of a film by peeling tension and subsequent conveyance tension | tensile_strength. For this reason, it is preferable that peeling tension and conveyance tension at the time of peeling a film from the endless belt support 12 shall be 50 N / m-400 N / m, for example.

In addition, the residual solvent rate of the film at the time of peeling a film from the endless belt support body 12 is completed after peelability from the endless belt support body 12, the residual solvent rate at the time of peeling, conveyability after peeling, conveyance, and drying. It is preferable that it is 30 mass%-200 mass% in consideration of the physical characteristic of the optical film used, and the like. In addition, the residual solvent rate of a film is defined by following formula (1).

Residual solvent rate (mass%) = Pa (M ₁ -M ₂ ) / M ₂ × 100 (1)

Here, M <_1> shows the mass at the arbitrary time of a film, and M <_2> shows the mass after drying the film which measured M <_1> at 115 degreeC for 1 hour.

The stretching apparatus 15 extends the film peeled from the endless belt support 12 in the direction orthogonal to the conveyance direction of a web (Transverse Direction: TD direction). Specifically, it extends in a TD direction by holding both ends of the direction orthogonal to the conveyance direction of a film with a clip, etc., and making the distance between the opposing clips large. In addition, although the extending | stretching apparatus 15 was provided in 1st Embodiment, it is not necessary to provide it. In that case, it is preferable to extend | stretch so that the elongation calculated | required by following formula (2) may be 10%-50%. Moreover, as the elongation, it is more preferable that it is 12%-48%, and it is still more preferable that it is 15%-45%.

Elongation (%) = {(length in the width direction before stretching-length in the width direction before stretching) / length in the width direction before stretching} × 100 (2)

When the elongation is too low, there is a tendency for which a desired retardation value cannot be obtained and a widening of the optical film becomes difficult. Moreover, when elongation rate is too high, the haze of a film will become high and there exists a tendency for transparency to fall. For this reason, when using the obtained optical film as retardation film with which liquid crystal display devices, such as a liquid crystal panel, are equipped, there exists a tendency for contrast to fall and it is not preferable. In some cases, the film may be torn and broken from the portion held by the gripping means (clip).

Moreover, when extending a film, it carries out by heating a film normally. Heating of this film may be performed by spraying heating wind on a film, for example, and you may heat with heating apparatuses, such as an infrared heater. Moreover, as temperature (stretching temperature) at the time of extending | stretching, it is preferable that it is 100 degreeC-200 degreeC, and it is more preferable that it is 120 degreeC-180 degreeC. When extending | stretching temperature is too low, since extra stress is added to a film, haze of a film becomes high and there exists a tendency for transparency to fall. For this reason, when the obtained film is used as retardation film with which liquid crystal display devices, such as a liquid crystal panel, are equipped, there exists a tendency for contrast to fall and it is not preferable. In some cases, the film may be torn and broken from the portion held by the gripping means (clip). Moreover, when extending | stretching temperature is too high, a desired retardation value will not be obtained or a film will melt | dissolve and there exists a tendency for the surface state, film thickness, etc. of a film to become nonuniform.

And the extending | stretching apparatus 15 may be equipped with the apparatus which cut | disconnects the area | region holding the clip.

In addition, although the total residual solvent rate of the film extended | stretched by the extending | stretching apparatus 15 is not specifically limited, From a viewpoint of workability by the drying apparatus 17, etc., it is 1 mass%-20 mass%, for example. desirable. In addition, when not providing the extending | stretching apparatus 15, it is preferable that the total residual solvent rate of a film shall be 1 mass%-20 mass% until it supplies a film to the drying apparatus 17.

The drying apparatus 17 is equipped with the some conveyance roller, and dries a film, while conveying a film between the rollers. In that case, heating air, infrared rays, etc. may be used independently, and you may dry using heating air and infrared rays together. It is preferable to use heating air from the point of simplicity. As drying temperature, although a suitable temperature differs according to the amount of residual solvent of a film, if it selects suitably and selects by the amount of residual solvent in the range of 30 degreeC-180 degreeC in consideration of drying time, shrinkage nonuniformity, stability of expansion amount, etc., do. Moreover, you may dry at a fixed temperature, and you may divide into the temperature of 2 to 4 steps, and may divide into several steps of temperature, and may dry. In addition, while conveying the inside of the drying apparatus 17, you may extend | stretch a film in MD (Machine Direction) direction. As for the residual solvent amount of the film after the drying process in the drying apparatus 17, 0.01 mass%-15 mass% are preferable in consideration of the load of a drying process, the dimensional stability stretching ratio at the time of storage, etc.

The winding apparatus 18 winds up the film which became predetermined | prescribed residual solvent ratio in the drying apparatus 17 to the winding core, after embossing by the hot embossing mechanism in the width direction both ends. In addition, it is preferable to cool to the room temperature in order to prevent the temperature at the time of winding up, a little scratches, winding looseness, etc. by the shrinkage | contraction after winding up. The winding machine to be used can be used without particular limitation, and what is necessary is just to be generally used, and it can wind up by winding methods, such as the constant tension method, the constant torque method, the taper tension method, and the program tension control method with constant internal stress.

Moreover, although the film forming apparatus 23 is equipped with the extending | stretching apparatus 15 and the drying apparatus 17, it does not need to be equipped and may be provided in two or more places, respectively.

(Optical film)

Moreover, the optical film manufactured as mentioned above is excellent in transparency, heat resistance, moisture resistance, and workability. Specifically, for example, the composition is also different depending on the composition, but the haze of the produced optical film is preferably 1% or less, and more preferably 0.5% or less. In addition, the variation of haze is small. Specifically, for example, it is preferable that the haze at three positions in the width direction of the optical film is measured, and the rate of change of the maximum value and the minimum value of the measured haze is less than 10%. Here, the measurement of the haze of an optical film can be measured according to JISK7136. Specifically, it can measure using a haze meter (NDH2000 type | mold by Nippon Denshoku Industries Co., Ltd.) etc., for example.

Moreover, it is preferable that the width | variety of an optical film is 1000 mm-4000 mm from the point of use to a large liquid crystal display device, the use efficiency of the optical film at the time of polarizing plate processing, and production efficiency. Moreover, it is preferable that the film thickness of an optical film is 30 micrometers-90 micrometers from a point of view of thickness reduction of a liquid crystal display device, production stabilization of an optical film, etc. A film thickness is an average film thickness here, 20-200 places and a film thickness are measured in the width direction of an optical film with the contact film thickness gauge by Mitsuto Co., Ltd., and the average value of the measured value is made into a film. Shown as thickness.

(Polarizer)

Moreover, the optical film of this invention can be used as a transparent protective film for polarizing plates for protecting the polarizing element of a polarizing plate. Specifically, a polarizing plate is equipped with a polarizing element and the transparent protective film arrange | positioned on the surface of the said polarizing element, for example. And the optical film of this invention can be used as this transparent protective film. A polarizing element is an optical element which converts incident light into polarized light and emits it.

As a polarizing plate, what bonded together the optical film using the fully saponified polyvinyl alcohol aqueous solution on at least one surface of the polarizing element produced by immersing and extending a polyvinyl alcohol-type film in iodine solution, for example is preferable. In addition, an optical film may be laminated | stacked on the other surface of a polarizing element, and the transparent protective film for another polarizing plate may be laminated | stacked. As a transparent protective film for this polarizing plate, it is KC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UY-HA, KC8UX-RHA (above, Konica Minolta Opto Co., Ltd. make), for example as a commercial cellulose-ester film. Etc. are used preferably. Or you may use resin films, such as cyclic olefin resin, acrylic resin, polyester, polycarbonate, other than a cellulose ester film. In this case, since saponification ability is low, it is preferable to carry out adhesive processing to a polarizing plate through a suitable adhesive layer.

As above-mentioned, a polarizing plate uses an optical film as a transparent protective film laminated | stacked on at least one surface side of a polarizing element. In that case, when an optical film acts as retardation film, it is preferable to arrange | position so that the slow axis of an optical film may be substantially parallel or orthogonal to the absorption axis of a polarizing element.

Moreover, as a specific example of a polarizing element, a polyvinyl alcohol-type polarizing film is mentioned, for example. The polyvinyl alcohol-based polarizing film has a thing which dyed iodine to the polyvinyl alcohol-type film, and the thing which dyed the dichroic dye. As the polyvinyl alcohol-based film, a modified polyvinyl alcohol-based film modified with ethylene is preferably used.

A polarizing element is obtained as follows, for example. First, it forms into a film using polyvinyl alcohol aqueous solution. The obtained polyvinyl alcohol-based film is uniaxially stretched and then dyed, or dyed and uniaxially stretched. And preferably, durability treatment is performed with a boron compound.

It is preferable that the film thickness of a polarizing element is 5 micrometers-40 micrometers, It is more preferable that it is 5 micrometers-30 micrometers, It is more preferable that it is 5 micrometers-20 micrometers.

When bonding a cellulose-ester type optical film on the surface of a polarizing element, it is preferable to bond together by the water-based adhesive agent which has fully saponified polyvinyl alcohol etc. as a main component. In addition, in the case of optical films other than the cellulose ester type optical film, it is preferable to carry out adhesive processing to a polarizing plate through a suitable adhesion layer.

Since the optical film is excellent in transparency, heat resistance, moisture resistance, and workability by using the optical film of this invention as a transparent protective film as mentioned above, it is suitable for the large screen liquid crystal display device, for example. A polarizing plate which can be used easily is obtained. Specifically, even if it is the polarizing plate for large screen liquid crystal display devices, distortion by moisture absorption etc. are suppressed. Moreover, since the optical film of this invention which is favorable in workability is used as a transparent protective film, generation | occurrence | production of a damage is suppressed even if a large optical film is used.

(Liquid crystal display device)

Moreover, the polarizing plate provided with the optical film of this invention can be used as a polarizing plate with which a liquid crystal display device is equipped. Specifically, a liquid crystal display device is equipped with a liquid crystal cell and two polarizing plates arrange | positioned so that a liquid crystal cell may be interposed. And a polarizing plate can be used as at least one polarizing plate of two polarizing plates. In addition, with a liquid crystal cell, a liquid crystal substance is filled between a pair of electrodes, The orientation state of a liquid crystal changes by applying a voltage to this electrode, and the amount of transmitted light is controlled. Such a liquid crystal display device is a transparent protective film for a polarizing plate, and since the optical film of this invention is excellent in transparency, heat resistance, moisture resistance, and workability by using the optical film of this invention, even if it is a large screen, it is an image display. The liquid crystal display device in which generation | occurrence | production of the problem of the optical film arrange | positioned at the area | region is suppressed can be provided. Moreover, since the processability of an optical film is favorable, even if it is a large optical film applied to the large screen liquid crystal display device, since the occurrence of damage of an optical film is suppressed at the time of manufacture, a large screen liquid crystal display device can be provided. .

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto.

Example

Example 1

(Acrylic resin particle)

Acrylic resin particle C1 was prepared as a resin particle as follows.

First, 38.2 liters of ion-exchanged water and 111.6 g of sodium dioctyl sulfo succinate were added to a reactor with a 60 liter reflux cooler, and the temperature was raised to 75 ° C. under a nitrogen atmosphere while stirring at 250 rpm, thereby effecting oxygen. It was virtually absent. Then, 0.36 g of ammonium persulfate (APS) was added and stirred for 5 minutes. Thereafter, a mixture of monomers consisting of 1657 g of methyl methacrylate (MMA), 21.6 g of n-butyl acrylate (BA) and 1.68 g of allyl methacrylate (ALMA) was added all at once, and after detecting an exothermic peak, Hold for 20 minutes. By doing so, the monomer was polymerized and the innermost hard layer was formed.

Next, 3.48 g of APS was thrown into the reactor with a reflux cooler as it was, and the stirring was carried out for 5 minutes. And the monomer mixture which consists of 105 g of BA8, 31.9 g of polyethyleneglycol diacrylate (PEGDA, molecular weight 200), and 264.0 g of ALMA was continuously added over 120 minutes, and after completion | finish of addition, it hold | maintained for 120 minutes again. By doing so, the monomer was polymerized and the thing in which the soft layer was formed on the innermost hard layer was obtained.

Next, 1.32 g of APS was added to the reactor with a reflux condenser in a state where the soft layer was formed on the innermost hard layer, and stirred for 5 minutes. And the monomer mixture which consists of 106 g of MMA2 and 201.6 g of BA was continuously added over 20 minutes, and after completion | finish of addition, it hold | maintained for 20 minutes again. By doing so, the monomer was polymerized and the thing in which the 1st outermost hard layer was formed on the soft layer was obtained.

Next, 1.32 g of APS was added to a reactor with a reflux condenser with the first outermost hard layer formed therein, and after 5 minutes, MMA 3148 g, BA 201.6 g, and 1-octyl mercaptan (n-OM) 10.1 g. The monomer mixture which consisted of was continuously added over 20 minutes, and after completion | finish of addition, it hold | maintained for 20 minutes further. Thereafter, the temperature was further increased to 95 ° C. and maintained for 60 minutes. By doing so, the dispersion liquid which superposed | polymerized the monomer and disperse | distributed the multilayer structure acrylic resin granular composite body (acrylic resin particle C1) in which the 2nd outermost hard layer was formed on the 1st outermost hard layer was obtained. In addition, a small amount of the dispersion liquid thus obtained was collected, and the volume average particle diameter was determined by the absorbance method. As a result, the presence of particles having a volume average particle diameter of 0.10 µm was confirmed.

And the dispersion liquid was thrown in 3 mass% sodium sulfate hot water solution, it salted and solidified, and then dehydration and washing were repeated. Then, the multilayer structure acrylic resin granular composite (acrylic resin particle C1) was obtained by drying.

(Preparation of acrylic resin particle-containing dispersion liquid)

First, in order to add surfactant previously, the acrylic resin particle containing dispersion liquid was prepared as follows.

In a kiln (not shown) provided with a stirring apparatus similar to the dope injection kiln (container) 1 shown in FIG. 1, 1 mass part and 1 mass of acrylic resin particle C1 which were prepared as acrylic resin particle as a solvent are methylene chloride. 15 mass parts and 2 mass parts of ethanol are added, 0.75 mass part of sodium dodecyl benzene sulfonates (Electert S-412-2 from Anko Takeshi Co., Ltd .: anionic surfactant) are added as surfactant, stirring, An acrylic resin particle-containing dispersion liquid (a mixture of a resin particle dispersion liquid and a surfactant) was prepared.

(Preparation of dope)

Next, the dope containing acrylic resin particle containing dispersion liquid was prepared.

40 parts by mass of methyl methacrylate resin (Dialal BR88 manufactured by Mitsubishi Rayon Co., Ltd.) and cellulose ester-based resin are used as an acrylic resin in an injection kiln (container) of an optical film manufacturing apparatus as shown in FIG. 1. As an example, 59 mass parts of cellulose acetate propionate resin (acyl group total substitution degree: 2.75, acetyl group substitution degree: 0.19, propionyl group substitution degree: 2.56, Mw: 200000), 18.75 mass parts of prepared acrylic particle containing dispersion liquid, It was added together with 285 parts by mass of methylene chloride and 38 parts by mass of ethanol. In that case, the mixing ratio (mass ratio) of acrylic resin, cellulose ester resin, and acrylic resin particle is set as the mixing ratio shown in Table 1. The methylene chloride and ethanol contained in the dope were 300 parts by mass and 40 parts by mass because the methylene chloride and ethanol contained in the acrylic particle-containing dispersion liquid were included.

And the compound in a container was heated, stirring. And dope was prepared by stirring until acrylic resin and cellulose ester-type resin melt | dissolve. Then, the obtained dope was cooled to 35 degreeC, and it filtered using the filter provided with the filter paper of 0.005 mm of filtration precision.

Using this filtered dope, the optical film was produced as follows.

(Manufacture of an optical film)

First, the temperature of the 2m wide endless belt support body was adjusted to 22 degreeC. The prepared dope was adjusted to 35 ° C, fed to a flexible die (coat hanger die) through piping, and an endless belt support polished from a flexible die (coat hanger die) to stainless steel or a cemented carbide surface at a traveling speed of 60 m / min. The dope prepared in was flexible. By doing so, the cast film (web) was formed on an endless belt support body, and it conveyed, drying. And the peeling tension was 100 N / m, the solvent evaporated from the endless belt support body, and the formed film was peeled off. At that time, it dried so that the residual solvent ratio of the film at the time of peeling might be 100%.

And the peeled film was dried, carrying out roll conveyance in 35 degreeC atmosphere. Thereafter, when the residual solvent ratio was 10%, the film was stretched 1.1 times in the width direction while holding both ends of the film with a clip in an atmosphere at 135 ° C. using a stretching apparatus (tenter). And after extending | stretching the stretched film at 130 degreeC for 5 minutes, it dried while conveying roll in 120 degreeC or 140 degreeC atmosphere. In addition, a residual solvent rate shows the value calculated | required by Formula (1) described in the specification main body.

Then, the area | region hold | gripped with the clip was cut out using the cutting device, and the film of width 1.5m was obtained. And after performing the knurling process which forms the convex part of width 10mm and height 5micrometer in the both ends of the obtained film, it wound up by the winding-up apparatus and manufactured the roll-shaped optical film.

[Examples 2 to 22]

The optical film was manufactured like Example 1 except having changed the component to contain and its content on the conditions shown in Table 1.

Specifically, for example, the acrylic resin particles used when producing the acrylic resin particle-containing dispersion liquid, the type of the surfactant, the amount of the surfactant added are changed to those shown in Table 1, or the acrylic system used when the dope is prepared. The kind of resin and cellulose-ester type resin, and its content were changed into what is shown in Table 1, and the optical film was manufactured.

In addition, in Table 1, BR-85 used as acrylic resin represents the diamond BR85 by Mitsubishi Rayon Corporation. 80N represents Delpet 80N manufactured by Asahi Kasei Chemical Co., Ltd.

In addition, in Table 1, the acrylic resin particle C2 and acrylic resin particle C3 used as acrylic resin particle are the methino MR-made by Mitsubishi Rayon Co., Ltd. metabrene W-341 and Soken Kagaku Co., Ltd., respectively. 2G.

In addition, in Table 1, the electrostripper F used as surfactant shows polyoxyethylene alkyl ether phosphate (Electro stripper F: anionic surfactant by the Kao Corporation). Elegan 264WAX represents a modified fatty acid dimethylethylammonium ethosulfate (Elegan 264WAX, a cationic surfactant manufactured by Nichi Oil Co., Ltd.). S-100 represents glycerin monostearate (Likemal S-100: nonionic surfactant made by Rickenvitamin Co., Ltd.). Elecut S-531 represents a quaternary ammonium salt (Elecut S-531 made from Takemoto Yushi Co., Ltd .: cationic surfactant).

(Comparative Examples 1 to 4 and 6)

The optical film was changed in the same manner as in Example 1 except that the components to be contained and the content thereof were changed to the conditions shown in Table 1, and the dope was prepared using all the components instead of adjusting the acrylic resin particle-containing dispersion liquid in advance. Was prepared. That is, it is similar to Example 1 except having added so-called pre-addition which adjusts acrylic resin containing dispersion liquid beforehand in the container substantially simultaneously with the component shown in Table 1, and its content (directly adding), and preparing dope. , An optical film was prepared.

(Comparative Example 5)

The optical film was manufactured like Example 1 except having changed the component to contain and its content to the conditions shown in Table 1, and preparing dope. That is, the optical film was manufactured like Example 1 except having prepared dope without using surfactant.

(Comparative Example 7)

The optical film was manufactured like Example 1 except having changed the component to contain and its content on the conditions shown in Table 1.

The following evaluation was performed about Examples 1-22 and Comparative Examples 1-7.

(Hayes)

First, the haze of the manufactured optical film was measured according to JIS K 7136. Specifically, in the width direction of the manufactured optical film, three haze of the edge part and the center part were measured using the haze meter (NDH2000 type by the Nippon Denshoku Industries Co., Ltd.). And the change rate of the minimum and maximum value of the measured haze was computed. The rate of change is a value obtained by dividing the difference between the maximum value and the minimum value by the maximum value. And if this change rate was less than 10%, it evaluated as "(circle)", and if it exceeded 10% and less than 30%, it evaluated as "(triangle | delta)" and if it exceeded 30%, it evaluated as "x".

(Processability: ductile fracture)

First, the test body of the size of 100 mm x 10 mm was cut out from the manufactured optical film. The cut test body was subjected to a bone folding and a mountain folding one time so that a folding line was formed at the central portion in the longitudinal direction, and it was confirmed whether or not the folded test body was cracked. And the same operation as this was performed 3 times. In addition, splitting here means that a test body is divided into two parts.

As a result, it evaluated as "(circle)" when it did not split once, and evaluated as "x" when it divided even once. Moreover, the brittleness of an optical film can be evaluated from this evaluation.

(Processability: cutting property)

Using the light load tear test machine manufactured by Toyo Seiki Seisakusho, the manufactured optical film was teared, and the tearing surface etc. were visually confirmed. At that time, if the tear surface is very smooth and ruptured, it is evaluated as "○", and if the tear surface can be confirmed to some extent, but if it is ruptured immediately, it is evaluated as "△", and if it is not broken immediately, "× Was evaluated.

(Heat resistance)

First, the manufactured optical film was cut | disconnected so that it might become the size of 10 cm x 10 cm. And the cut optical film was used as the test piece. The test piece was left to stand for 1000 hours in 90 degreeC and the atmosphere of a dry state (relative humidity 5% RH or less). Then, the deformation | transformation of the optical film was visually confirmed. If the deformation of the optical film can not be confirmed, it is evaluated as &quot;? &Quot;, and when one deformation of the film is confirmed, the evaluation is &quot; Respectively.

(Moisture resistance)

A cross mark was attached to the casting | flow_spread direction (length direction) of the manufactured optical film as two marks. The distance between the two labels was measured using an optical microscope.

And the optical film with this label was heat-treated by leaving it to stand for 1000 hours in the atmosphere of 60 degreeC and 90% of a relative humidity. Then, the distance between two labels was measured again using the optical microscope.

The change rate (dimension change rate) of the distance was computed from following formula (3) using the distance between markers measured as mentioned above.

Dimensional rate of change (%) = [(L1-L2) / L1] x 100 (3)

In formula, L1 represents the distance before heat processing, and L2 represents the distance after heat processing.

And if the dimensional change rate was less than 0.3%, it evaluated as "(circle)", and if it was 0.3% or more and less than 0.5%, it evaluated as "(triangle | delta)" and if it was 0.5% or more, it evaluated as "x".

Hereinafter, the evaluation results are shown in Table 2.

As can be seen from Table 1 and Table 2, as a dope containing acrylic resin, cellulose ester resin, and acrylic resin particles, a dispersion of acrylic particles is previously mixed with a surfactant, and the mixture is mixed with acrylic resin and cellulose ester. When the dope obtained by adding system resin to the liquid mixed with a solvent so that it may become 95: 5-30: 70 by mass ratio (Examples 1-22), the dispersion liquid of acrylic resin particle is previously mixed with surfactant. If not used (Comparative Examples 1 to 4 and 6), transparency, heat resistance, moisture resistance and processability are compared with those without using a surfactant (Comparative Example 5) and when the acrylic resin is too small (Comparative Example 7). It can be seen that an excellent optical film can be produced.

1: dope infusion kiln (container)
2: dope feed pump
3: dope political kiln
4, 5: strainer
6: discharge valve
7: piping
11: manufacturing apparatus of optical film
12: endless belt support
13: flexible die
14: peeling roller
15: drawing device
17: drying device
18: winding device
19: dope
20: Heat exchanger
21: dope manufacturing apparatus
22: filtration device
23: film forming apparatus

Claims (11)

At least as a manufacturing method of the dope for optical films which has a resin particle, acrylic resin, and a cellulose ester-type resin,
A first mixing step of preparing a mixture by mixing the dispersion liquid of the resin particles and a surfactant;
It has a resin composition of the said acrylic resin and the said cellulose ester-type resin of the range of 95: 5-30: 70 by mass ratio, and the 2nd mixing step which mixes a solvent and the said mixture, The manufacture of the dope for optical films characterized by the above-mentioned. Way. The method of claim 1,
The said resin particle is acrylic resin particle, The manufacturing method of the dope for optical films characterized by the above-mentioned. The method according to claim 1 or 2,
The said surfactant is an ionic surfactant, The manufacturing method of the dope for optical films characterized by the above-mentioned. The method of claim 3,
The said ionic surfactant is an anionic surfactant, The manufacturing method of the dope for optical films characterized by the above-mentioned. 5. The method according to any one of claims 1 to 4,
Content of the said surfactant is 500 mass parts or less with respect to 100 mass parts of said resin particles, The manufacturing method of the dope for optical films characterized by the above-mentioned. The method according to any one of claims 1 to 5,
The mass ratio of the said acrylic resin and the said cellulose ester-type resin is 95: 5-50: 50, The manufacturing method of the dope for optical films characterized by the above-mentioned. The method according to any one of claims 1 to 5,
The mass ratio of the said acrylic resin and the said cellulose ester-type resin is 80: 20-60: 40, The manufacturing method of the dope for optical films characterized by the above-mentioned. A casting step of forming a film by flexing the dope on the support that runs;
In the manufacturing method of the optical film which has a peeling process which peels the said film from the said support body,
The said dope is dope for optical films manufactured by the manufacturing method of the dope for optical films of any one of Claims 1-7, The manufacturing method of the optical film characterized by the above-mentioned. It is obtained by the manufacturing method of the optical film of Claim 8, The optical film characterized by the above-mentioned. As a polarizing plate provided with a polarizing element and the transparent protective film arrange | positioned on at least one surface of the said polarizing element,
The said transparent protective film is the optical film of Claim 9, The polarizing plate characterized by the above-mentioned. A liquid crystal display device comprising a liquid crystal cell and two polarizing plates arranged to sandwich the liquid crystal cell therebetween,
At least one of the said two polarizing plates is a polarizing plate of Claim 10, The liquid crystal display device characterized by the above-mentioned.

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