WO2022215407A1 - Production method for polarizing plate protection film - Google Patents

Production method for polarizing plate protection film Download PDF

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Publication number
WO2022215407A1
WO2022215407A1 PCT/JP2022/009683 JP2022009683W WO2022215407A1 WO 2022215407 A1 WO2022215407 A1 WO 2022215407A1 JP 2022009683 W JP2022009683 W JP 2022009683W WO 2022215407 A1 WO2022215407 A1 WO 2022215407A1
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Prior art keywords
film
stretching
polarizing plate
web
range
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PCT/JP2022/009683
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French (fr)
Japanese (ja)
Inventor
乃傲 許
卓哉 小出
Original Assignee
コニカミノルタ株式会社
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Publication date
Application filed by コニカミノルタ株式会社 filed Critical コニカミノルタ株式会社
Priority to CN202280026459.1A priority Critical patent/CN117157564A/en
Priority to JP2023512869A priority patent/JPWO2022215407A1/ja
Priority to KR1020237031540A priority patent/KR20230144085A/en
Publication of WO2022215407A1 publication Critical patent/WO2022215407A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/0074—Production of other optical elements not provided for in B29D11/00009- B29D11/0073
    • B29D11/00788—Producing optical films
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/24—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of indefinite length
    • B29C41/28—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of indefinite length by depositing flowable material on an endless belt
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/34—Component parts, details or accessories; Auxiliary operations
    • B29C41/38—Moulds, cores or other substrates
    • B29C41/383—Moulds, cores or other substrates with means for cutting the article
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/34—Component parts, details or accessories; Auxiliary operations
    • B29C41/46—Heating or cooling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/34—Component parts, details or accessories; Auxiliary operations
    • B29C41/52—Measuring, controlling or regulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
    • B29C55/06—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/00634—Production of filters
    • B29D11/00644—Production of filters polarizing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D7/00—Producing flat articles, e.g. films or sheets
    • B29D7/01—Films or sheets
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements

Definitions

  • the present invention relates to a method for manufacturing a polarizing plate protective film. More particularly, it relates to a method for producing a polarizing plate protective film containing a cycloolefin polymer having improved adhesion to a polyvinyl alcohol film.
  • Cellulose ester polymers such as triacetyl cellulose are suitable for polarizing plate protective films used in liquid crystal display polarizing plates because of their low birefringence and are often used.
  • a polarizing plate is generally a film made of a polyvinyl alcohol-based film or the like in which iodine or a dye is adsorbed and oriented (hereinafter also referred to as "polarizing film”, “polarizer film” or “polarizer film”) and on both sides thereof , and laminated transparent polymer (resin) film layers.
  • polarizing film a polyvinyl alcohol-based film or the like in which iodine or a dye is adsorbed and oriented
  • polarizer film polarizer film
  • polarizer film laminated transparent polymer
  • a protective film of triacetyl cellulose is often used as the transparent polymer film layer, but various improvement methods have been proposed in response to the demand for high-level performance from various viewpoints in recent years.
  • Patent Literature 1 discloses a technique for controlling angular unevenness in the slow axis direction of a cellulose ester-based protective film when producing a polarizing plate protective film.
  • cycloolefin-based polymers are superior to cellulose ester-based polymers in terms of transparency, optical properties, durability, etc. Therefore, polarizing plate protective films using such cycloolefin-based polymers can be used in liquid crystal displays.
  • the demand for use in display devices such as devices is increasing year by year.
  • the protective film of the cycloolefin-based polymer like the protective film of the cellulose ester-based polymer, is still inadequate in meeting the demand for high performance.
  • a new problem was discovered that there is room for improvement in the adhesiveness between the polarizing film and the polarizing plate protective film.
  • the present invention has been made in view of the above problems and circumstances, and the problem to be solved is to provide a method for producing a polarizing plate protective film containing a cycloolefin-based polymer having improved adhesion to a polyvinyl alcohol-based polarizing film. to provide.
  • the present inventors have investigated the causes of the above problems, etc., and found that when manufacturing a polarizing plate protective film, the relative relationship between the transport speed of the film in the raw film manufacturing process and the processing process.
  • the present inventors have found that the film surface condition can be improved and the above problems can be solved by controlling the amount of residual solvent in the film during stretching within a certain range. That is, the above problems related to the present invention are solved by the following means.
  • a method for producing a polarizing plate protective film containing a cycloolefin polymer comprising: It has a raw film manufacturing process and a processing process, The raw film manufacturing process includes at least a step of casting the dope onto a support at a conveying speed V1 to form a web, and a first-stage stretching of the web width immediately after casting the web.
  • the processing step includes a step of conveying the wound film at a conveying speed V2 that satisfies the following formula (1) and performing a second stage stretching, Formula (1): V 1 ⁇ V 2 Furthermore, in the step of stretching the wound film in the second stage, the amount of residual solvent immediately before the second stage stretching with respect to the winding width is 0.1 to 0.5% by mass.
  • a method for producing a polarizing plate protective film characterized in that stretching is performed within the range of
  • the relative relationship between the transport speed of the film in the raw film production process and the processing process and the amount of residual solvent in the film during stretching are controlled within a certain range.
  • the condition of the film surface can be improved. That is, first, in the raw film manufacturing process, the polymer constituent molecules in the film (web) are stretched in the first stage with a considerable amount of solvent remaining in the film, such as the orientation of the polymer molecular chains. It is presumed that the physicochemical condition of the surface was made suitable for the improvement of adhesiveness by preventing the formation of a dense layer that was biased in the direction of the surface.
  • the residual solvent is diffused during the second stage of stretching, and the high It is possible to suppress the formation of a density layer, and by adjusting the amount of residual solvent to a certain amount or less, it prevents excessive penetration of the adhesive into the film and prevents deterioration of the strength of the film. presumed to have been possible.
  • a method for producing a polarizing plate protective film of the present invention is a method for producing a polarizing plate protective film containing a cycloolefin-based polymer, comprising a raw film manufacturing step and a processing step, wherein the raw film manufacturing step includes: At least, the steps of casting the dope onto a support at a conveying speed V1 to form a web, stretching the web in the first stage with respect to the width of the web just after casting, and drying the web.
  • the wound film is conveyed at a conveying speed V2 that satisfies the following formula (1), and is stretched in the second stage.
  • the amount of residual solvent immediately before the second stage stretching with respect to the winding width is 0.1 to 0.5% by mass. It is characterized by stretching within the range of.
  • the amount of residual solvent immediately before the first stage of stretching is within the range of 1 to 15% by mass, and the stretching ratio is within the range of 1.1 to 2.0 times. is preferable from the viewpoint of improving film adhesion and suppressing deterioration of film strength.
  • the draw ratio in the step of drawing in the second stage is within the range of 1.1 to 2.0 times from the viewpoint of effect expression.
  • a method for producing a polarizing plate protective film of the present invention is a method for producing a polarizing plate protective film containing a cycloolefin-based polymer, comprising a raw film manufacturing step and a processing step, wherein the raw film manufacturing step includes: At least, the steps of casting the dope onto a support at a conveying speed V1 to form a web, stretching the web in the first stage with respect to the width of the web just after casting, and drying the web.
  • the wound film is conveyed at a conveying speed V2 that satisfies the following formula (1), and is stretched in the second stage.
  • FIG. 1 is a flow chart showing the flow of the manufacturing process of the present invention
  • FIG. 2 is a schematic diagram of an apparatus for manufacturing a polarizing plate protective film.
  • the original film according to the present invention is a film manufactured by a solution casting film-forming method, and in the original film manufacturing process, at least the dope is cast onto the support at a conveying speed of V1. forming a web by stretching the web, stretching the web to the width of the web immediately after casting, and drying the web to wind up the film.
  • the step of casting the dope onto a support at a conveying speed V1 to form a web includes It consists of a dope preparation step (S1), a casting step (S2), and a stripping step (S3).
  • Dope preparation (stirring preparation) step (S1) In the dope preparation (stirring preparation) step (S1), at least the resin and the solvent are stirred in the stirring tank 1a of the stirring device 1 to prepare the dope to be cast on the support 3 (endless belt).
  • COP cycloolefin polymer
  • This step is a step of dissolving the COP and, in some cases, other compounds in a dissolution tank in a solvent mainly composed of a good solvent for the cycloolefin polymer (COP) while stirring to form a dope, or the COP solution. Then, if necessary, other compound solutions are mixed to form a dope, which is the main solution.
  • a solvent mainly composed of a good solvent for the cycloolefin polymer (COP) while stirring to form a dope, or the COP solution.
  • other compound solutions are mixed to form a dope, which is the main solution.
  • the concentration of the cycloolefin polymer (COP) in the dope is preferably as high as possible because the drying load after casting onto the support can be reduced. However, if the concentration of COP is too high, the load during filtration will increase and the accuracy will deteriorate.
  • the concentration that satisfies these requirements is preferably in the range of 10 to 35% by mass, more preferably in the range of 15 to 30% by mass.
  • solvent used in dope The solvent used in the dope may be used alone or in combination of two or more, but it is preferable to use a mixture of a good solvent and a poor solvent for the cycloolefin polymer (COP) from the viewpoint of production efficiency. In view of the solubility of COP, it is preferable to use a large amount of a good solvent.
  • a preferable range of the mixing ratio of the good solvent and the poor solvent is 70 to 98% by mass of the good solvent and 2 to 30% by mass of the poor solvent.
  • the term "good solvent” or “poor solvent” refers to a good solvent that dissolves the cycloolefin polymer (COP) used alone, and a poor solvent that swells or does not dissolve alone. Define. Therefore, depending on the type and number of substituents of COP, it may be a good solvent or a poor solvent.
  • organic halogen compounds such as methylene chloride, dioxolanes, acetone, methyl acetate, methyl acetoacetate and the like can be mentioned. Particularly preferred are methylene chloride and methyl acetate.
  • the poor solvent used in the present invention is not particularly limited, for example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone and the like are preferably used. Also, the dope preferably contains 0.01 to 2.00% by mass of water.
  • the solvent used for dissolving the cycloolefin polymer is used by recovering the solvent removed from the film by drying in the process of forming the polarizing plate protective film and reusing it.
  • the recovery solvent may contain trace amounts of additives added to the COP, such as plasticizers, UV absorbers, polymers, monomer components, etc., even if these are contained, they should preferably be reused. It can be purified and reused if necessary.
  • a general method can be used as the method for dissolving the COP when preparing the dope described above. Specifically, a method of performing at normal pressure, a method of performing at the boiling point of the main solvent or less, and a method of pressurizing at the boiling point or higher of the main solvent are preferable, and a combination of heating and pressurization enables heating to the boiling point or higher at normal pressure.
  • a method of stirring and dissolving while heating at a temperature above the boiling point of the solvent at normal pressure and within a range in which the solvent does not boil under pressure is also preferable in order to prevent the generation of massive undissolved substances called gels and lumps. .
  • a method of mixing a cycloolefin polymer (COP) with a poor solvent to wet or swell it, and then adding a good solvent to dissolve it is also preferably used.
  • COP cycloolefin polymer
  • Pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or a method of increasing the vapor pressure of the solvent by heating. Heating is preferably performed from the outside, and for example, a jacket type is preferable because temperature control is easy.
  • an inert gas such as nitrogen gas
  • a jacket type is preferable because temperature control is easy.
  • a higher heating temperature with the addition of a solvent is preferable, but if the heating temperature is too high, the required pressure increases and productivity deteriorates.
  • the heating temperature is preferably in the range of 30 to 120°C, more preferably in the range of 60 to 110°C, even more preferably in the range of 70 to 105°C. Also, the pressure is adjusted so that the solvent does not boil at the set temperature.
  • a cooling dissolution method is also preferably used, whereby the cycloolefin polymer (COP) can be dissolved in a solvent such as methyl acetate.
  • filtration Next, it is preferable to filter this cycloolefin-based polymer (COP) solution (dope during or after dissolution) using an appropriate filter medium such as filter paper.
  • COP cycloolefin-based polymer
  • the filter medium preferably has a small absolute filtration accuracy in order to remove insoluble matter and the like. For this reason, a filter medium with an absolute filtration accuracy of 0.008 mm or less is preferable, a filter medium with an absolute filtration accuracy within the range of 0.001 to 0.008 mm is more preferable, and a filter medium with an absolute filtration accuracy within the range of 0.003 to 0.006 mm is even more preferable.
  • the material of the filter medium there are no particular restrictions on the material of the filter medium, and ordinary filter mediums can be used. preferable.
  • a bright spot foreign matter is when two polarizing plates are placed in a crossed Nicols state, a film or the like is placed between them, and light is applied from one polarizing plate side and observed from the other polarizing plate side. It is a point (foreign matter) that looks like light leaking from the side, and the number of bright spots with a diameter of 0.01 mm or more is preferably 200/cm 2 or less. It is more preferably 100/cm 2 or less, still more preferably 50/cm 2 or less, still more preferably 10/cm 2 or less. Also, it is preferable that the number of bright spots of 0.01 mm or less is small.
  • Filtration of the dope can be carried out by an ordinary method, but a method of filtering while heating at a temperature above the boiling point of the solvent at normal pressure and within a range in which the solvent does not boil under pressure is preferred because the filtration pressure before and after filtration is reduced. It is preferable because the difference (referred to as differential pressure) is small.
  • the temperature is preferably in the range of 30-120°C, more preferably in the range of 45-70°C, even more preferably in the range of 45-55°C.
  • Casting step (S2) In the casting step (S2), the web 5 formed by the dope cast on the support 3 at the conveying speed V1 is heated on the support 3, and the web 5 is separated from the support 3 by the peeling roller 4. Evaporate the solvent until it can be peeled off. Then, the amount of residual solvent immediately before the first stage of stretching is controlled by evaporation of the solvent.
  • the above evaporation is preferably carried out in an atmosphere within the range of 5 to 75°C.
  • To evaporate the solvent there are a method of applying hot air to the upper surface of the web and/or a method of transferring heat from the back surface of the support 3 with a liquid, and a method of transferring heat from the front and back by radiant heat.
  • a heat transfer method is preferred because of its high drying efficiency.
  • the method of combining them is also preferably used.
  • the casting width is preferably 1.3 m or more from the viewpoint of productivity. More preferably, it is within the range of 1.3 to 4.0 m. If the casting width does not exceed 4.0 m, streaks will not occur in the manufacturing process, and the stability in the subsequent transport process will be high. From the viewpoint of transportability and productivity, the range of 1.3 to 3.0 m is more preferable.
  • the support 3 in the casting step (S2) preferably has a mirror-finished surface, and as the support 3, a stainless steel belt or a casting drum with a plated surface is preferably used.
  • the surface temperature of the support 3 in the casting step (S2) is within the range of -50°C to the boiling point of the solvent.
  • the support temperature is preferably in the range of 0 to 55°C, more preferably in the range of 22 to 50°C.
  • a method for controlling the temperature of the support 3 is not particularly limited, but there are a method of blowing hot or cold air and a method of contacting the back side of the support with hot water.
  • the use of hot water is preferable because it takes less time to reach a constant temperature of the support because heat is transferred more efficiently.
  • the air may have a higher temperature than the target temperature.
  • the dope prepared in the dope preparation step (S1) is sent through a pressurized constant gear pump or the like to the casting die 2 through a conduit, and is transported endlessly by a rotary driven stainless steel endless belt.
  • a dope is cast from a casting die 2 onto a casting position on a support 3 made of the dope.
  • the portion of the casting die slit where the dope comes out is called a lip, and a casting die is preferable because the slit shape of the lip portion can be adjusted and the film thickness can be easily made uniform.
  • Casting dies include coat hanger dies, T dies, and the like, and all of them are preferably used.
  • the term "web" refers to the dope film cast from the lip portion.
  • two or more of the above-mentioned casting dies may be provided on the support, and the dope amount may be divided for layering.
  • the slit can be narrowed by manually turning and pushing the heat bolt to make the film thinner, or conversely, it can be opened to make it thicker. It is also common to apply a voltage to the heat bolt to push it in by heat, but it is usually used in combination. It is also possible to adopt a method of pushing and pulling. However, due to the mechanism of the casting die, it may not be possible to narrow the pitch of the bolts, and in the case of dope with high viscosity (including melted), the pressure load on the lip when the casting die is discharged is large, and the load after discharge is increased. In some cases, the width of the film thickness varies, such as a rapid decrease and an increase in the film thickness (balus effect). Therefore, it is necessary to design the lip of the casting die so that the internal structure of the casting die does not apply too much load.
  • the dope cast at the conveying speed V 1 is dried on the support 3 to form the web 5 .
  • the inclination of the casting die 2, that is, the direction in which the dope is discharged from the casting die 2 to the support 3 is an angle of 0 to 90 with respect to the normal to the surface of the support 3 (the surface on which the dope is cast). ° may be set as appropriate.
  • the support 3 is made of, for example, a stainless steel belt and held by a pair of rollers 3a and 3b and a plurality of rollers positioned therebetween. At this time, the surface of the support is preferably a mirror surface.
  • rollers 3a and 3b are provided with a drive for applying tension to the support 3, whereby the support 3 is used under tension.
  • the support 3 may be a drum.
  • peeling step (S3) In this step, in the casting step (S2), the solvent is evaporated on the support 3 until the film strength becomes such that the web 5 can be peeled off. strips the web from the support 3 before it makes one turn. That is, this step is a step of peeling off the web from which the solvent has evaporated on the support 3 at the peeling position. At this time, from the viewpoint of surface quality, moisture permeability, and releasability, it is preferable to release the base film from the support within 30 to 600 seconds. The position where the web is peeled off from the support is called the peeling point, and the roll that assists the peeling is called the peeling roller.
  • the web is peeled off by the peeling roller 4 while maintaining self-supporting properties.
  • the temperature at the peeling position on the support is preferably in the range of -50 to 40°C, more preferably in the range of 10 to 40°C, most preferably in the range of 15 to 30°C.
  • the amount of residual solvent immediately before the first stage of stretching is appropriately adjusted depending on the strength of the drying conditions, the length of the support 3, and the like. Although it depends on the thickness of the web, if the amount of residual solvent at the peeling point is too large, the web may be too soft and difficult to peel off, resulting in loss of flatness, horizontal steps, creases, and vertical streaks due to peeling tension. It may occur more easily. Conversely, if the amount of residual solvent is too small, the web may partially peel off during the process.
  • the amount of residual solvent is preferably in the range of 1 to 50% by mass from the viewpoint of balancing economic speed and quality. Also, from the viewpoint of exhibiting the effect of the present invention, it is preferably in the range of 1 to 15% by mass.
  • the film-forming speed As a method for increasing the film-forming speed (the film-forming speed can be increased because the film is peeled off while the amount of residual solvent is as large as possible), there is a gel casting method that allows the film to be peeled off even when the amount of residual solvent is large.
  • the method includes adding a poor solvent for the cycloolefin polymer (COP) to the dope, gelling the web after dope casting, and cooling the support to gel the web and remove the residual solvent.
  • COP cycloolefin polymer
  • Residual solvent amount (mass%) ⁇ (MN) / N ⁇ ⁇ 100
  • M is the mass of a sample taken at an arbitrary point during or after the production of the web or polarizing plate protective film
  • N is the mass after heating M at 115° C. for 1 hour.
  • the amount of residual solvent can be measured by headspace gas chromatography.
  • the sample is sealed in a container, heated, and with the container filled with volatile components, the gas in the container is quickly injected into the gas chromatograph, and mass spectrometry is performed to identify the compound. Volatile components are quantified while the measurement is being carried out.
  • the headspace method makes it possible to observe all peaks of volatile components by gas chromatograph, and quantifies volatile substances and monomers with high accuracy by using an analytical method that uses electromagnetic interaction. It can be done together.
  • the peeling tension when peeling the support from the web is preferably 300 N/m or less. More preferably, the tension is in the range of 196 to 245 N/m, but if wrinkles are likely to occur during peeling, it is preferable to peel with a tension of 190 N/m or less.
  • Step of first-stage stretching of the web width immediately after casting This step is the step of first-stage stretching (S4), and the web is peeled off from the support. It is carried out by stretching in the machine direction (hereinafter also referred to as "MD direction”).
  • MD direction machine direction
  • TD direction transverse direction
  • the stretching may be carried out depending on the required optical properties, preferably in at least one direction, and in two directions perpendicular to each other (for example, the width direction (TD direction) of the film and the direction perpendicular to it).
  • Biaxial stretching in the transport direction (MD direction) may be performed.
  • the draw ratio is defined as (stretching direction size of the film after stretching)/(stretching direction size of the film before stretching).
  • the stretching ratio is preferably in the range of 1.1 to 2.0 in both the TD and MD directions.
  • the residual solvent amount immediately before the first stage of stretching in the present invention is synonymous with the residual solvent amount at the peeling point in the peeling step (S3) described above.
  • the amount of residual solvent immediately before the first stage of stretching is within the range of 1 to 15% by mass, and the stretching ratio is within the range of 1.1 to 2.0 times. is preferable from the viewpoint of improving film adhesion and suppressing deterioration of film strength.
  • the first-stage stretching step (S4) promotes entanglement between polymer molecules (matrix molecules) in the thickness direction of the web. Even in the case of bonding via an agent, the adhesive easily permeates into the polarizing plate protective film via the entangled portions (crosslinked portions) between matrix molecules. As a result, the polarizing plate protective film can be firmly fixed to the polarizer layer (also referred to as "polarizing film”, “polarizer film” or “polarizer film”) via the adhesive, and the polarizer layer It is possible to improve the peel strength of the polarizing plate protective film against. That is, the adhesiveness between the polarizing plate protective film and the polarizer layer is improved, and the function of suppressing deterioration of film strength can be ensured.
  • the web is shrunk in the width direction.
  • a method for shrinking the web for example, (1) the web is subjected to a high temperature treatment without being held widthwise to increase the density of the web; There are methods such as shrinking the web in the width direction (TD direction) and (3) sharply reducing the amount of residual solvent in the web.
  • Step of drying the web and winding up the film formed This step consists of a drying step (S5), a first cutting step (S6) and a first winding step (S7).
  • the dope transport speed V1 in the dope preparing step (S1) and the winding speed in the first winding step (S7) are the same speed.
  • Drying step (S5) is a step of heating the web on the support, evaporating the solvent, and winding up the formed film.
  • the web is transported by a plurality of transport rollers arranged in a zigzag pattern when viewed from the side, and the web is dried in the meantime.
  • the drying method in the drying device 7 is not particularly limited, and hot air, infrared rays, heating rollers, microwaves, etc. are generally used to dry the web. preferable. Moreover, the method of combining them is also preferable. In addition, the drying step (S5) may be performed as necessary.
  • the film thickness of the web is thin, it dries quickly, but too rapid drying tends to impair the flatness of the finished film.
  • Drying is generally carried out in the range of 30-250° C. throughout. In particular, it is preferable to dry within the range of 35 to 200° C., and it is preferable to increase the drying temperature stepwise.
  • the temperature of the support may be the same throughout or may vary depending on the position.
  • a roller drying method (a method in which the web is alternately passed through a number of rollers arranged above and below to dry it) and a tenter method are used to dry the web while it is transported.
  • a tenter stretching device When a tenter stretching device is used, it is preferable to use a device that can independently control the left and right gripping lengths of the web (the distance from the start of gripping to the end of gripping) by left and right gripping means of the tenter stretching device in the stretching step described later.
  • First cutting step (S6) In the first cutting step (S6), the cutting section 8 made of a slitter is stretched in the step of stretching in the first stage (S4), and the both ends in the width direction of the film F that has undergone the drying step (S5) are cut. do. In the film F, the portion remaining after the cutting of both ends constitutes the product portion which will be the film product. On the other hand, the portion cut from the film F may be recovered and reused as part of the raw material for forming the polarizing plate protective film.
  • First Winding Step (S7) In the first winding step (S7), the film F is wound by the winding device 9 at the conveying speed V 1 (winding speed V 1 ), and the original film manufacturing step is completed.
  • a preferable range of the initial tension when winding the film F in the winding process is in the range of 20 to 300 N/m.
  • the wound film is conveyed at a conveying speed V2 that satisfies the following formula (1) through the step (S8) of unwinding from the roll body, and is stretched in the second stage. It consists of at least a feeding step (S8), a second drawing step (S9), a second cutting step (S10), and a second winding step (S11).
  • the amount of residual solvent immediately before the second stage of stretching is in the range of 0.1 to 0.5% by mass.
  • the second stage stretching step (S9) may be a step of stretching the film only in the MD direction within the film plane, may be a step of stretching only in the TD direction, or may be a step of stretching in the MD direction and the TD direction. , or may be a step of stretching in an oblique direction.
  • the stretching direction is not limited, but from the viewpoint of obtaining a wide film, it is preferable that there is a step including at least stretching in the lateral direction. Such stretching can be performed using a stretching device 10 .
  • the film In order to secure a high retardation, secure a wide width, and promote the permeation of the adhesive when bonding to the polarizing film, it is preferable to stretch the film at a high magnification in the second stage of the stretching process. However, if the draw ratio is too high, the drawing stress may cause crazes in the film, or the entanglement between matrix molecules that maintain the film strength may be dissociated, thereby weakening the film.
  • the draw ratio in the second-stage drawing process is in the range of 1.1 to 2.0 times from the viewpoint of manifesting the effects of the present invention.
  • the stretching at the highest magnification at which the risk of dissociation of the matrix molecules is the highest among the multiple stretchings. It is preferable that the drawing be performed at the final time. Therefore, in the present invention, it is preferable that the stretching at the highest magnification is performed in the second stage of the stretching process. In this case, since the entanglement of the matrix molecules can be strengthened before the stretching at the maximum magnification, the dissociation of the entanglement of the matrix molecules can be suppressed and cohesive failure can be suppressed even when the stretching at the maximum magnification is performed.
  • the film F is stretched by the stretching device 10.
  • a stretching method at this time a method of stretching in the conveying direction (longitudinal direction of the film; film forming direction; casting direction; MD direction) by providing a peripheral speed difference between rollers;
  • a tenter system in which the film is fixed and stretched in the width direction (the direction perpendicular to the plane of the film; TD direction) is preferable in order to improve the performance, productivity, flatness and dimensional stability of the film.
  • Width retention and lateral stretching in the film-forming process are preferably carried out by a tenter-stretching device, which may be a pin tenter or a clip tenter.
  • a tenter-stretching device which may be a pin tenter or a clip tenter.
  • drying may be performed in addition to stretching.
  • Second cutting step (S10) In the second cutting step (S10), the cutting section 11 made of a slitter cuts both ends in the width direction of the film F stretched in the second stretching step (S9). In the film F, the portion remaining after the cutting of both ends constitutes the product portion which will be the film product. On the other hand, the portion cut from the film F may be recovered and reused as part of the raw material for forming the film.
  • Second Winding Step (S11) In the second winding step (S11), the film F is wound by the winding device 12 at the conveying speed V2. At this time, the thickness of the film is preferably in the range of 5 to 100 ⁇ m, more preferably in the range of 5 to 80 ⁇ m, even more preferably in the range of 5 to 40 ⁇ m. A preferable range of the initial tension when winding the film F in the second winding step (S11) is in the range of 20 to 300 N/m.
  • Winding method The method of winding the film F may use a generally used winder, and there are methods of controlling tension such as a constant torque method, a constant tension method, a taper tension method, and a program tension control method with constant internal stress. should be used properly.
  • edges of the film may be slit to the width of the product and cut off, and surface modification treatment may be applied to both ends of the film to prevent sticking and scratches during winding.
  • the polymer (resin) used in the method for producing the polarizing plate protective film of the present invention is a cycloolefin-based polymer (also referred to as “cycloolefin-based resin”). It is excellent in that it is easy to control the stretchability and crystallinity, that the adhesive easily permeates, and that it can ensure better adhesion to the polarizing film.
  • the polarizing plate protective film may be subjected to surface modification treatment after production.
  • the cycloolefin-based polymer contained in the polarizing plate protective film is preferably a polymer of cycloolefin monomers or a copolymer of cycloolefin monomers and other copolymerizable monomers.
  • the cycloolefin monomer is preferably a cycloolefin monomer having a norbornene skeleton, and a cycloolefin monomer having a structure represented by the following general formula (A-1) or (A-2) It is more preferable to have
  • R 1 to R 4 each independently represent a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a polar group.
  • p represents an integer of 0 to 2; However, R 1 to R 4 do not all represent a hydrogen atom at the same time, R 1 and R 2 do not represent a hydrogen atom at the same time, and R 3 and R 4 do not represent a hydrogen atom at the same time. do.
  • the hydrocarbon group having 1 to 30 carbon atoms represented by R 1 to R 4 in general formula (A-1) is preferably, for example, a hydrocarbon group having 1 to 10 carbon atoms. 1 to 5 hydrocarbon groups are more preferred.
  • a hydrocarbon group having 1 to 30 carbon atoms may further have a linking group containing, for example, a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom. Examples of such linking groups include divalent polar groups such as carbonyl groups, imino groups, ether bonds, silyl ether bonds and thioether bonds. Examples of hydrocarbon groups having 1 to 30 carbon atoms include methyl, ethyl, propyl, butyl and the like.
  • Examples of polar groups represented by R 1 to R 4 in general formula (A-1) include a carboxy group, a hydroxy group, an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amino group, an amido group and a cyano group. is included. Among them, a carboxy group, a hydroxy group, an alkoxycarbonyl group and an aryloxycarbonyl group are preferred, and an alkoxycarbonyl group and an aryloxycarbonyl group are preferred from the viewpoint of ensuring solubility during solution film formation.
  • p in formula (A-1) is preferably 1 or 2 from the viewpoint of enhancing the heat resistance of the polarizing plate protective film. This is because when p is 1 or 2, the resulting polymer becomes bulky and the glass transition temperature tends to be improved.
  • R 5 represents a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or an alkylsilyl group having an alkyl group having 1 to 5 carbon atoms.
  • R6 represents a carboxy group, hydroxy group, alkoxycarbonyl group, aryloxycarbonyl group, amino group, amido group, cyano group, or halogen atom (fluorine atom, chlorine atom, bromine atom or iodine atom).
  • p represents an integer of 0 to 2;
  • R 5 in general formula (A-2) preferably represents a hydrocarbon group having 1 to 5 carbon atoms, more preferably a hydrocarbon group having 1 to 3 carbon atoms.
  • R 6 in general formula (A-2) preferably represents a carboxy group, a hydroxy group, an alkoxycarbonyl group and an aryloxycarbonyl group.
  • An oxycarbonyl group is more preferred.
  • p in formula (A-2) preferably represents 1 or 2 from the viewpoint of enhancing the heat resistance of the polarizing plate protective film. This is because when p is 1 or 2, the resulting polymer becomes bulky and the glass transition temperature tends to be improved.
  • a cycloolefin monomer having a structure represented by general formula (A-2) is preferable from the viewpoint of improving the solubility in organic solvents.
  • breaking the symmetry of an organic compound lowers the crystallinity, thereby improving the solubility in an organic solvent.
  • R 5 and R 6 in general formula (A-2) are substituted only on one ring-constituting carbon atom with respect to the symmetry axis of the molecule, the symmetry of the molecule is low, that is, general formula (A- Since the cycloolefin monomer having the structure represented by 2) is highly soluble, it is suitable for producing a polarizing plate protective film by a solution casting method.
  • the content of the cycloolefin monomer having the structure represented by the general formula (A-2) in the cycloolefin monomer polymer is based on the total of all cycloolefin monomers constituting the cycloolefin polymer. For example, 70 mol % or more, preferably 80 mol % or more, more preferably 100 mol %.
  • the cycloolefin monomer having the structure represented by the general formula (A-2) is contained at a certain level or more, the orientation of the polymer increases, so the retardation value tends to increase.
  • copolymerizable monomers copolymerizable with cycloolefin monomers examples include copolymerizable monomers capable of ring-opening copolymerization with cycloolefin monomers, and addition copolymerization with cycloolefin monomers. possible copolymerizable monomers and the like.
  • copolymerizable monomers capable of ring-opening copolymerization include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene and dicyclopentadiene.
  • addition-copolymerizable copolymerizable monomers include unsaturated double bond-containing compounds, vinyl-based cyclic hydrocarbon monomers, and (meth)acrylates.
  • unsaturated double bond-containing compounds include olefinic compounds having 2 to 12 (preferably 2 to 8) carbon atoms, examples of which include ethylene, propylene and butene.
  • vinyl-based cyclic hydrocarbon monomers examples include vinylcyclopentene-based monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene.
  • (meth)acrylates examples include alkyl (meth)acrylates having 1 to 20 carbon atoms such as methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate and cyclohexyl (meth)acrylate.
  • the content of the cycloolefin monomer in the copolymer of the cycloolefin monomer and the copolymerizable monomer is, for example, 20 to 80 mol% with respect to the total of all monomers constituting the copolymer. within the range of, preferably within the range of 30 to 70 mol%.
  • the cycloolefin-based polymer is a cycloolefin monomer having a norbornene skeleton, preferably a cycloolefin monomer having a structure represented by general formula (A-1) or (A-2), or Polymers obtained by copolymerization, examples of which include polymers (1) to (7) below.
  • a ring-opening polymer of a cycloolefin monomer (2) A ring-opening copolymer of a cycloolefin monomer and a copolymerizable monomer capable of ring-opening copolymerization thereof (3) Above (1) or a hydrogenated product of the ring-opening (co)polymer of (2) (4) the ring-opening (co)polymer of (1) or (2) above is cyclized by the Friedel-Crafts reaction and then hydrogen is added (Co)polymer (5) Saturated copolymer of a cycloolefin monomer and an unsaturated double bond-containing compound (6) Addition copolymerization of a cycloolefin monomer with a vinyl-based cyclic hydrocarbon monomer Coalescence and its hydrogenation product (7) Alternating copolymer of cycloolefin monomer and (meth)acrylate
  • the above polymers (1) to (7) can all be obtained by known methods, for example, the methods described in JP-A-2008-107534 and JP-A-2005-227606.
  • the catalyst and solvent used in the ring-opening copolymerization of (2) above can be those described in paragraphs 0019 to 0024 of JP-A-2008-107534.
  • the catalyst used for the hydrogenated products of (3) and (6) above for example, those described in paragraphs 0025 to 0028 of JP-A-2008-107534 can be used.
  • the acidic compound used in the Friedel-Crafts reaction of (4) above for example, those described in paragraph 0029 of JP-A-2008-107534 can be used.
  • the catalyst used in the addition polymerization of (5) to (7) above for example, those described in paragraphs 0058 to 0063 of JP-A-2005-227606 can be used.
  • the alternating copolymerization reaction (7) above can be carried out, for example, by the method described in paragraphs 0071 and 0072 of JP-A-2005-227606.
  • the polymers (1) to (3) and (5) above are preferred, and the polymers (3) and (5) above are more preferred.
  • the cycloolefin-based polymer can increase the glass transition temperature of the obtained cycloolefin-based polymer and increase the light transmittance. It preferably contains at least one of the structural units represented by the following general formula (B-2), and contains only the structural unit represented by the general formula (B-2), or the general formula (B-1) It is more preferable to include both the structural unit represented by formula (B-2) and the structural unit represented by general formula (B-2).
  • the structural unit represented by general formula (B-1) is a structural unit derived from the cycloolefin monomer represented by general formula (A-1) described above, and is represented by general formula (B-2). is a structural unit derived from the cycloolefin monomer represented by the general formula (A-2) described above.
  • R 1 to R 4 and p have the same definitions as R 1 to R 4 and p in general formula (A-1), respectively.
  • R 5 to R 6 and p have the same definitions as R 5 to R 6 and p in general formula (A-2), respectively.
  • the cycloolefin-based polymer according to the present invention may be a commercial product.
  • Commercially available examples of cycloolefin-based polymers include JSR Corporation's Arton G (e.g. G7810), Arton F, Arton R (e.g. R4500, R4900 and R5000), and Arton RX. .
  • the intrinsic viscosity [ ⁇ ]inh of the cycloolefin polymer is preferably in the range of 0.2 to 5 cm 3 /g, more preferably in the range of 0.3 to 3 cm 3 /g, when measured at 30°C. is more preferable, and more preferably within the range of 0.4 to 1.5 cm 3 /g.
  • the number average molecular weight (Mn) of the cycloolefin polymer is preferably within the range of 8000 to 100000, more preferably within the range of 10000 to 80000, and even more preferably within the range of 12000 to 50000. .
  • the weight average molecular weight (Mw) of the cycloolefin polymer is preferably within the range of 20000 to 300000, more preferably within the range of 30000 to 250000, and even more preferably within the range of 40000 to 200000. .
  • the number average molecular weight and weight average molecular weight of the cycloolefin polymer can be measured by gel permeation chromatography (GPC) in terms of polystyrene.
  • the number average molecular weight and the weight average molecular weight are within the above ranges, the heat resistance, water resistance, chemical resistance, mechanical properties, and moldability as a film of the cycloolefin polymer are good. Become.
  • the glass transition temperature (Tg) of the cycloolefin polymer is usually 110° C. or higher, preferably in the range of 110 to 350° C., more preferably in the range of 120 to 250° C., and 120 to It is more preferably within the range of 220°C.
  • the glass transition temperature (Tg) is 110°C or higher, it is easy to suppress deformation under high temperature conditions.
  • the glass transition temperature (Tg) is 350° C. or less, the molding process becomes easy, and deterioration of the polymer (resin) due to heat during the molding process can be easily suppressed.
  • the content of the cycloolefin polymer is preferably 70% by mass or more, more preferably 80% by mass or more, relative to the film.
  • the polarizing plate according to the present invention has a polarizer layer, the polarizing plate protective film of the present invention, and an adhesive layer containing a water-based adhesive or an ultraviolet curable adhesive disposed therebetween.
  • the polarizer layer according to the present invention is a layer composed of at least a polarizing film (also referred to as “polarizer film” or “polarizer film”).
  • polarizer refers to an element that transmits only light with a plane of polarization in a certain direction.
  • the polarizing film according to the present invention is a polyvinyl alcohol-based polarizing film.
  • the polyvinyl alcohol-based polarizing film includes a polyvinyl alcohol-based film dyed with iodine and a polyvinyl alcohol-based film dyed with a dichroic dye.
  • the polyvinyl alcohol-based polarizing film may be a film obtained by uniaxially stretching a polyvinyl alcohol-based film and then dyeing it with iodine or a dichroic dye (preferably a film further subjected to durability treatment with a boron compound); A film obtained by dyeing an alcohol-based film with iodine or a dichroic dye and then uniaxially stretching the film (preferably, a film further subjected to a durability treatment with a boron compound) may be used.
  • the absorption axis of the polarizer layer is generally parallel to the direction of maximum stretch.
  • JP 2003-248123, JP 2003-342322, etc. ethylene unit content 1 to 4 mol%, degree of polymerization 2000 to 4000, degree of saponification 99.0 to 99.99 mol% Ethylene modified polyvinyl alcohol is used.
  • the thickness of the polarizer layer is preferably 5 to 30 ⁇ m, and more preferably 5 to 20 ⁇ m in order to thin the polarizing plate.
  • the polarizing plate protective film produced by the method for producing a polarizing plate protective film of the present invention is disposed on at least one surface (at least the surface facing the liquid crystal cell) of the polarizer layer. there is The surface of the polarizing plate protective film on which the polarizer layer is to be laminated is subjected to activation treatment, which will be described later.
  • the polarizing plate protective film produced by the method for producing a polarizing plate protective film of the present invention is disposed only on one surface of the polarizer layer, the other surface of the polarizer layer is coated with an optical film such as a retardation film. A film can be placed.
  • optical films examples include commercially available cellulose ester films (e.g., Konica Minolta Tac KC8UX, KC5UX, KC4UX, KC8UCR3, KC4SR, KC4BR, KC4CR, KC4DR, KC4FR, KC4KR, KC8UY, KC6UY, KC4UY, KC4UE, KC8UE, KC8UY-HA, KC2UA, KC4UA, KC6UA, KC8UA, KC2UAH, KC4UAH, KC6UAH, manufactured by Konica Minolta, Fujitac T40UZ, Fujitac T60UZ, Fujitac T80UZ, Fujitac TD80UL, Fujitac TD60UL, Fujitac TD60UL, Fujitac R0RL, TD40 (manufactured by Fuji Film Co., Ltd.).
  • the thickness of other optical films can be, for example, 5-100 ⁇ m, preferably 40-80 ⁇ m.
  • Adhesive Layer The adhesive layer is formed by drying a water-based adhesive or an ultraviolet curable adhesive described below, which is placed between the optical film (or other optical film) and the polarizer layer. .
  • the thickness of the adhesive layer can be, for example, 0.01 to 10 ⁇ m, preferably about 0.03 to 5 ⁇ m.
  • the method for producing a polarizing plate according to the present invention comprises: 1) a step of applying an activation treatment to the surface of the polarizing plate protective film; and 2) an activation treatment of the polarizing plate protective film. It has a step of laminating a polarizer layer (polarizing film) on the applied surface via a water-based adhesive or an ultraviolet curable adhesive, and 3) drying the obtained laminate.
  • Step 1 The surface of the polarizing plate protective film (the surface to be bonded to the polarizer layer) is subjected to an activation treatment. This makes it easier to obtain adhesiveness with the polarizer layer. Specifically, the siloxane bond, ether bond, tertiary carbon atom, etc. of the side chain of the specific graft polymer contained in the polarizing plate protective film are made hydrophilic by the activation treatment, thereby improving the affinity with the water-based adhesive. By increasing or facilitating interaction, the polarizing plate protective film and the polarizer layer are easily adhered.
  • activation treatments include corona treatment, plasma treatment and saponification treatment, preferably corona treatment and plasma treatment, more preferably corona treatment.
  • the conditions for the activation treatment should be such that the siloxane bonds, ether bonds, tertiary carbon atoms, etc. contained in the side chains of the specific graft polymer can be sufficiently activated.
  • the irradiation dose is preferably 100 to 1000 (W ⁇ min/m 2 ), more preferably 150 to 900 (W ⁇ min/m 2 ).
  • a polarizer layer is laminated on the activated surface of the optical film via a water-based adhesive or an ultraviolet curable adhesive.
  • water-based adhesive examples include vinyl-based, gelatin-based, vinyl-based latex-based, polyurethane-based, isocyanate-based, polyester-based, and epoxy-based adhesives.
  • a water-based adhesive containing a vinyl-based polymer is preferable from the viewpoint of easily obtaining adhesion to the polyvinyl alcohol-based polarizing film that is the polarizer layer. Alcohol aqueous solution, etc.) is more preferred.
  • a water-based adhesive containing a polyvinyl alcohol-based polymer may further contain a water-soluble cross-linking agent such as boric acid, borax, glutaraldehyde, melamine, or oxalic acid.
  • the ultraviolet curable adhesive may be a radically photopolymerizable composition or a cationic photopolymerizable composition. Among them, a photo-cationically polymerizable composition is preferred.
  • the photocationically polymerizable composition contains an epoxy compound and a photocationic polymerization initiator.
  • An epoxy-based compound is a compound having one or more, preferably two or more epoxy groups in the molecule.
  • epoxy compounds include hydrogenated epoxy compounds obtained by reacting epichlorohydrin with alicyclic polyols (glycidyl ethers of polyols having alicyclic rings); aliphatic polyhydric alcohols or their alkylene Aliphatic epoxy compounds such as polyglycidyl ethers of oxide adducts; and alicyclic epoxy compounds having one or more epoxy groups bonded to an alicyclic ring in the molecule.
  • Epoxy compounds may be used alone or in combination of two or more.
  • the photocationic polymerization initiator can be, for example, an aromatic diazonium salt; an onium salt such as an aromatic iodonium salt or an aromatic sulfonium salt; an iron-arene complex.
  • the photocationic polymerization initiator may further contain additives such as cationic polymerization accelerators such as oxetane and polyol, photosensitizers, and solvents, if necessary.
  • additives such as cationic polymerization accelerators such as oxetane and polyol, photosensitizers, and solvents, if necessary.
  • the thickness of the adhesive layer is not particularly limited, it can be, for example, 0.01 to 10 ⁇ m, preferably about 0.01 to 5 ⁇ m.
  • Step 3 the obtained laminate is dried to obtain a polarizing plate.
  • Drying can be performed by heat drying.
  • the drying temperature may be any temperature that sufficiently dries the water-based adhesive or the UV-curable adhesive, and may be, for example, 60 to 100.degree.
  • additives may be contained in addition to the above cycloolefin polymer (COP) as other additives.
  • the polarizing plate protective film preferably contains at least one kind of plasticizer for the purpose of imparting workability to the polarizing plate protective film, for example.
  • the plasticizers are preferably used singly or in combination of two or more.
  • plasticizers the inclusion of at least one plasticizer selected from the group consisting of sugar esters, polyesters, and styrenic compounds is effective in controlling moisture permeability and forming base polymers (resins) such as cellulose esters. It is preferable from the viewpoint of being able to achieve a high degree of compatibility.
  • the plasticizer preferably has a molecular weight of 15,000 or less, more preferably 10,000 or less, from the viewpoint of achieving both improvement in wet heat resistance and compatibility with the base polymer (resin) such as cellulose ester.
  • the weight average molecular weight (Mw) is preferably 10,000 or less.
  • a preferred weight average molecular weight (Mw) range is 100 to 10,000, more preferably 400 to 8,000.
  • the compound having a molecular weight of 1500 or less is preferably contained within the range of 6 to 40 parts by mass with respect to 100 parts by mass of the base polymer (resin), and 10 to 20 parts by mass. It is more preferable to contain within the range of parts by mass. By containing it within the above range, it is possible to achieve both effective control of moisture permeability and compatibility with the base resin, which is preferable.
  • the polarizing plate protective film may contain a sugar ester compound for the purpose of preventing hydrolysis.
  • a sugar ester compound for the purpose of preventing hydrolysis.
  • a sugar ester compound having at least 1 to 12 pyranose structures or at least one furanose structure and having all or part of the OH groups in that structure esterified can be used. .
  • the polarizing plate protective film can also contain polyester.
  • the polyester is not particularly limited, but for example, a polymer (polyester polyol) having a terminal hydroxy group obtained by a condensation reaction between a dicarboxylic acid or an ester-forming derivative thereof and a glycol, or a terminal hydroxy group of the polyester polyol.
  • a polymer whose groups are blocked with monocarboxylic acid (terminal-blocked polyester) can be used.
  • esteer-forming derivative as used herein means an esterified product of dicarboxylic acid, a dicarboxylic acid chloride, and an anhydride of dicarboxylic acid.
  • styrene compound for the polarizing plate protective film, a styrene compound may be used in addition to or instead of the above sugar esters and polyesters for the purpose of improving the water resistance of the polarizing plate protective film.
  • the styrene-based compound may be a homopolymer of a styrene-based monomer, or a copolymer of a styrene-based monomer and another copolymerizable monomer.
  • the content of structural units derived from styrene-based monomers in the styrene-based compound is preferably in the range of 30 to 100 mol%, more preferably 50 to 100 mol%, in order for the molecular structure to have a certain or higher bulkiness. can be in range.
  • styrenic monomers include styrene; alkyl-substituted styrenes such as ⁇ -methylstyrene, ⁇ -methylstyrene and p-methylstyrene; halogen-substituted styrenes such as 4-chlorostyrene and 4-bromostyrene; hydroxystyrenes such as styrene, ⁇ -methyl-p-hydroxystyrene, 2-methyl-4-hydroxystyrene, 3,4-dihydroxystyrene; vinylbenzyl alcohols; p-methoxystyrene, p-tert-butoxystyrene, m Alkoxy-substituted styrenes such as -tert-butoxystyrene; vinyl benzoic acids such as 3-vinylbenzoic acid and 4-vinylbenzoic acid; 4-vinylbenzyl acetate; 4-acetoxy
  • the polarizing plate protective film may contain other optional components such as antioxidants, colorants, UV absorbers, matting agents, acrylic particles, hydrogen-bonding solvents and ionic surfactants. These components can be added within the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of the base polymer (resin).
  • the polarizing plate protective film can use commonly known antioxidants.
  • lactone, sulfur, phenol, double bond, hindered amine, and phosphorus compounds can be preferably used.
  • antioxidants and the like are added within the range of 0.05 to 20% by mass, preferably within the range of 0.1 to 1% by mass, relative to the polymer (resin) that is the main raw material of the polarizing plate protective film.
  • a synergistic effect can be obtained by using several different types of compounds in combination rather than using only one of these antioxidants. For example, combined use of lactone, phosphorus, phenol and double bond compounds is preferred.
  • the polarizing plate protective film preferably contains a coloring agent for color adjustment within a range that does not impair the effects of the present invention.
  • a coloring agent means a dye or a pigment, and in the present invention, refers to a substance that has the effect of making the color tone of the liquid crystal screen bluish, adjusting the yellow index, or reducing haze.
  • dyes and pigments can be used as coloring agents, but anthraquinone dyes, azo dyes, phthalocyanine pigments, etc. are effective.
  • the polarizing plate protective film can be used on the viewing side or the backlight side of the polarizing plate, it may contain an ultraviolet absorber for the purpose of imparting an ultraviolet absorbing function.
  • the ultraviolet absorber is not particularly limited, but includes, for example, benzotriazole-based, 2-hydroxybenzophenone-based, and salicylic acid phenyl ester-based ultraviolet absorbers.
  • benzotriazole-based 2-hydroxybenzophenone-based
  • salicylic acid phenyl ester-based ultraviolet absorbers for example 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis( ⁇ , ⁇ -dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(3,5 triazoles such as -di-t-butyl-2-hydroxyphenyl)benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone and 2,2'-dihydroxy-4-methoxybenzophenone, etc. benzophenones can be exemplified.
  • the ultraviolet absorbers may be used singly or in combination of two or more.
  • the amount of the ultraviolet absorber used varies depending on the type of ultraviolet absorber, usage conditions, etc., but is generally within the range of 0.05 to 10% by mass, preferably It is added within the range of 0.1 to 5% by mass.
  • the polarizing plate protective film preferably contains fine particles that impart lubricity to the polarizing plate protective film.
  • the addition of fine particles is effective from the viewpoint of improving the slipperiness of the surface of the polarizing plate protective film according to the present invention, improving the slipperiness during winding, and preventing the occurrence of scratches and blocking. be.
  • the fine particles may be either inorganic fine particles or organic fine particles as long as they do not impair the transparency of the obtained polarizing plate protective film and have heat resistance when melted, but inorganic fine particles are more preferable. These fine particles can be used alone or in combination of two or more.
  • silicon dioxide is particularly preferably used because it has a refractive index close to that of the cycloolefin-based polymer, acrylic polymer and cellulose ester-based polymer and has excellent transparency (haze).
  • silicon dioxide examples include Aerosil (registered trademark) 200V, Aerosil (registered trademark) R972V, Aerosil (registered trademark) R972, R974, R812, 200, 300, R202, OX50, TT600, NAX50 (Nippon Aerosil Co., Ltd.
  • the shape of the particles may be irregular, needle-like, flat, spherical, or the like, without any particular limitation.
  • Use of spherical particles is particularly preferable because the obtained polarizing plate protective film can have good transparency.
  • the particle size is close to the wavelength of visible light, the light will scatter and the transparency will deteriorate. .
  • the particle size is in the range of 80 to 180 nm.
  • the size of the particles means the size of the aggregate when the particles are aggregates of primary particles. When the particles are not spherical, it means the diameter of a circle corresponding to their projected area.
  • the fine particles are preferably added within the range of 0.05 to 10% by mass, preferably within the range of 0.1 to 5% by mass, relative to the base polymer (resin).
  • the polarizing plate protective film produced by the production method of the present invention can also be used as a retardation film, and is suitably used as a protective film for polarizing plates, etc., and is used in various optical measurement devices and liquid crystals. It can be used for display devices such as display devices and organic electroluminescence display devices.
  • the film has a water contact angle of 75 to 85° under the following measurement conditions. preferably within the range.
  • the water contact angle was measured by a contact angle meter (Kyowa Interface Science Co., Ltd.) in an atmosphere of 23°C and 55% relative humidity after leaving the sample for 24 hours in an atmosphere of 23°C and 55% relative humidity.
  • a contact angle meter Kelowa Interface Science Co., Ltd.
  • DropMaster DM100 manufactured by the same company
  • measurement was performed 1 minute after dropping 1 ⁇ L of pure water.
  • the measurement was performed 5 times, and the average value of the measured values was taken as the water contact angle.
  • the surface layer density of the film is preferably 1.9 to 2.0 g/cm 3 from the viewpoint of film adhesion.
  • surface layer density refers to the average density per unit volume of a region up to 100 nm (0.1 ⁇ m) in the thickness direction from the surface.
  • the average density can be calculated using X-ray reflectometry (XRR) as described in paragraphs [0011] to [0018] of Japanese Patent No. 4921612. X-rays are totally reflected when incident on the film at very shallow angles.
  • the X-rays When the angle of incident X-rays exceeds the critical angle for total reflection, the X-rays enter the inside of the film and are divided into transmitted waves and reflected waves at the film surface and interfaces, and the reflected waves interfere with each other.
  • the density of the film By analyzing the critical angle of total reflection, the density of the film can be obtained, and by taking the average value of each, the average density can be obtained.
  • the average density in a region up to 100 nm (0.1 ⁇ m) in the thickness direction from the surface is obtained by measuring the X-ray reflectance under the measurement conditions shown below to determine the total reflection critical angle ⁇ c, and from that value, the density ⁇ is calculated. Further, for this density ⁇ , the distribution in the thickness direction (density distribution) in a region from the surface to 100 nm (0.1 ⁇ m) in the thickness direction is obtained, and the average value of this density distribution is calculated as the average density. did.
  • the measurement equipment and measurement conditions are as follows.
  • Measurement device Sample horizontal X-ray diffraction device for thin film evaluation “SmartLab” manufactured by Rigaku Corporation Measurement conditions: X-ray source; Cu-K ⁇ 1 (wavelength: 1.54059 ⁇ )
  • Optical system parallel beam optical system
  • Incident side slit system Ge (220) 2 crystal, height limiting slit 5 mm, incident slit 0.05 mm
  • Light-receiving side slit system light-receiving slit 0.10 mm, solar slit 5° Detector; scintillation counter Tube voltage/tube current; 45 kV/200 mA Scanning axis; 2 ⁇ / ⁇ Scanning mode; continuous scanning Scanning range; 0.1-3.0 deg. Scanning speed; 1 deg. /min. Sampling interval; 0.002°/step
  • Breaking point stress is an index that indicates the force when a film is continuously pulled in a certain direction to cause breakage. It is possible to suppress breakage and deformation in the processing process.
  • the amount of residual solvent immediately before the second stage of stretching must be in the range of 0.1 to 0.5% by mass, and from the viewpoint of suppressing the formation of a high-density layer formed on the film surface
  • the amount of the adhesive permeating into the finished film becomes excessive and the strength of the film becomes weak.
  • the film is conveyed at a conveying speed V 2 that satisfies the following formula (1), and the residual solvent amount immediately before the second stage stretching is within the range of 0.1 to 0.5% by mass.
  • V 1 ⁇ V 2 the stress at break is preferably in the range of 2.1 to 2.7 GPa, preferably 2.4 to 2.7 GPa from the viewpoint of film strength.
  • the breaking point stress of the polarizing plate protective film according to the present invention is measured by cutting the polarizing plate protective film into a strip having a length of 70 mm (TD: width direction) ⁇ 10 mm (MD: length direction), Using a tensile tester (RTC-1225A, manufactured by Orientec Co., Ltd.), a tensile test is performed at a room temperature of 23 ° C. and a relative humidity of 55% at an initial tension chuck distance of 50 mm and a tensile speed of 50 mm / min. It is obtained from the load-strain curve.
  • RTC-1225A tensile tester
  • the measurement is performed five times for each sample, and the average value thereof is used for evaluation.
  • the breaking point stress in the longitudinal direction of the polarizing plate protective film is set to 2.1 GPa or more, it is possible to suppress breakage and deformation even when force is applied to the film in the longitudinal direction. It becomes easy to suppress the deterioration of the yield due to the deformation and the deterioration of the optical properties and quality of the obtained film.
  • Preparation of polarizing plate protective film> (Preparation of polarizing plate protective film No. 1) A solution casting film forming method was used to form the polarizing plate protective film.
  • composition 1 Cyclic polyolefin polymer (P-1) 150 parts by mass Dichloromethane 380 parts by mass Methanol 70 parts by mass
  • composition 2 containing the cyclic polyolefin solution (dope) prepared by the above method was put into a disperser to prepare a fine particle dispersion (M-1) as an additive.
  • composition 2 Fine particles (Aerosil R812: manufactured by Nippon Aerosil Co., Ltd., primary average particle size: 7 nm, apparent specific gravity 50 g / L) 4 parts by mass Dichloromethane 76 parts by mass Methanol 10 parts by mass Cyclic polyolefin solution (Dope D-1) 10 parts by mass
  • the dope (polymer (resin) composition cycloolefin-based polymer: COP) prepared in the dope preparation step (S1) is passed through a pressurized metering gear pump to a casting die through a conduit, and is transported endlessly.
  • the dope is cast from a casting die onto a casting position on a support made of a steel endless belt in a film production line with a width of 1800 mm, and heated on the support until the dope has self-supporting properties.
  • a web was formed by drying by evaporating the solvent until the web could be peeled off by a peel roller.
  • the dope transport speed V1 was 40 [m / min].
  • Step (S4) of stretching the web in the first stage with respect to the width of the web immediately after casting The web was subjected to a high temperature treatment without being held laterally to increase the density of the web, and the web was stretched in the first stage while shrinking in the lateral direction. At this time, when the amount of residual solvent immediately before the first stage of stretching was measured, it was 12% by mass. Moreover, it implemented by the draw ratio of 1.50 times.
  • the polarizing plate protective film No. 1 was obtained. 1 was produced.
  • the film thickness of the polarizing plate protective film produced by the above process was 40 ⁇ m.
  • the manufactured polarizing plate protective film No. The water contact angle, the surface layer density of the film, and the stress at break of film No. 1 were measured, and each value was evaluated.
  • polarizing plate protective film Nos. 2 to 15 Dope transport speed V 1 , which is the first-stage stretching condition in the raw film manufacturing process, residual solvent amount and stretch ratio immediately before the first-stage stretching, and film transport speed V 2 , which is the second-stage stretching condition, Except for changing the amount of residual solvent and the draw ratio just before the second-stage drawing as shown in Table I, the polarizing plate protective film No. Polarizing plate protective film No. 1 was prepared in the same manner as in No. 1. 2 to 15 were produced. Moreover, the prepared polarizing plate protective film No. The water contact angle, film surface layer density and breaking point stress were measured for 2 to 15, and each value was evaluated.
  • the water contact angle is within the range of 75 to 85 ° ⁇ : The water contact angle is greater than 85 ° and 88 ° or less ⁇ : The water contact angle is greater than 88 ° and 90 ° or less Note that the value outside the above range (75 ° less than or greater than 90°) were excluded from the above evaluation range because they were not calculated as measured values.
  • Breaking point stress is in the range of 2.4 to 2.7 GPa
  • Breaking point stress is 2.1 GPa or more and less than 2.4 GPa
  • Breaking point stress is less than 2.1
  • a value outside the above range (2 .7 GPa) were excluded from the above evaluation range because they were not calculated as measured values.
  • polarizer layer (polarizing film) A 70 ⁇ m-thick polyvinyl alcohol-based film was swollen with water at 35°C. The above film was immersed in an aqueous solution of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and further immersed in an aqueous solution of 3 g of potassium iodide, 7.5 g of boric acid and 100 g of water at 45°C. The above film was uniaxially stretched under conditions of a stretching temperature of 55° C. and a stretching ratio of 5 times. This uniaxially stretched film was washed with water and then dried to obtain a 20 ⁇ m-thick polarizer layer (polarizing film: polyvinyl alcohol-iodine-based polarizer layer).
  • the polyvinyl alcohol-iodine polarizer layer was laminated to the adhesive layer obtained by the above operation.
  • optical film no. 1 to 12 were laminated to prepare a polarizing plate.
  • an ultraviolet irradiation device with a belt conveyor (a lamp using a D bulb manufactured by Fusion UV Systems Co., Ltd.) is used from both sides of the laminated laminate. Then, ultraviolet rays were irradiated so that the integrated amount of light was 750 mJ/cm 2 to cure the ultraviolet curing adhesive layer.
  • Each of the obtained laminates was dried in an oven at 90°C for 10 minutes to obtain a polarizing plate having a laminated structure of polarizing plate protective films.
  • Peel strength is 2.0 (N / 25 mm) or more ⁇ : Peel strength is in the range of 1.0 to 2.0 (N / 25 mm) ⁇ : Peel strength is less than 1.0 (N / 25 mm)

Abstract

The present invention addresses the problem of providing a production method for a polarizing plate protection film that contains a cycloolefin polymer having improved adhesion to a polyvinyl alcohol film.　This production method for a polarizing plate protection film is characterized by comprising at least: a rolled source film production step including a step for forming a web through flow-casting of a dope on a support at a transport speed V1, a step for performing the first stage of stretching on the web having a web width immediately after the flow-casting, and a step for rolling up a film formed by drying the web; and a processing step including a step for transporting the rolled-up film at a transport speed V2 satisfying V1<V2 and performing the second stage of stretching thereon. In the step for performing the second stage of stretching on the rolled-up film, the stretching is performed such that the amount of a residual solvent immediately before the second stage of stretching with respect to the rolled-up width falls within the range of 0.1-0.5 mass%.

Description

偏光板保護フィルムの製造方法Method for manufacturing polarizing plate protective film
　本発明は、偏光板保護フィルムの製造方法に関する。より詳しくは、ポリビニルアルコール系フィルムとの接着性が改良されたシクロオレフィン系ポリマーを含有する偏光板保護フィルムの製造方法に関する。 The present invention relates to a method for manufacturing a polarizing plate protective film. More particularly, it relates to a method for producing a polarizing plate protective film containing a cycloolefin polymer having improved adhesion to a polyvinyl alcohol film.
　液晶ディスプレイの偏光板に用いられる偏光板保護フィルムとしては、トリアセチルセルロース等のセルロースエステル系ポリマーがその複屈折性が小さいことから適しており、よく用いられている。 Cellulose ester polymers such as triacetyl cellulose are suitable for polarizing plate protective films used in liquid crystal display polarizing plates because of their low birefringence and are often used.
　偏光板は、一般に、ヨウ素や染料を吸着配向させたポリビニルアルコール系フィルム等からなるフィルム（以下において、「偏光フィルム」、「偏光子フィルム」又は「偏光子膜」ともいう。）とその両面に、積層された透明なポリマー（樹脂）フィルム層とで構成されている。
　この透明なポリマーフィルム層としては、従来、トリアセチルセルロースの保護フィルムがよく使われているが、近年の種々の観点からの高いレベルの性能の要望に対し、種々の改良方法が提案されている。
　例えば偏光板保護フィルムの作製時に、セルロースエステル系の保護フィルムの遅相軸方向の角度むらを制御する技術が特許文献１に公開されている。 A polarizing plate is generally a film made of a polyvinyl alcohol-based film or the like in which iodine or a dye is adsorbed and oriented (hereinafter also referred to as "polarizing film", "polarizer film" or "polarizer film") and on both sides thereof , and laminated transparent polymer (resin) film layers.
Conventionally, a protective film of triacetyl cellulose is often used as the transparent polymer film layer, but various improvement methods have been proposed in response to the demand for high-level performance from various viewpoints in recent years. .
For example, Patent Literature 1 discloses a technique for controlling angular unevenness in the slow axis direction of a cellulose ester-based protective film when producing a polarizing plate protective film.
　一方、シクロオレフィン系ポリマーは、セルロースエステル系ポリマーに比べ、透明性、光学特性、耐久性等に優れている点があることから、当該シクロオレフィン系ポリマーを用いた偏光板保護フィルムを、液晶表示装置等の表示装置に用いることの要望が年々高まってきている。
　しかしながら、シクロオレフィン系ポリマーの保護フィルムも、セルロースエステル系ポリマーの保護フィルムと同様に高い性能上の要望に対して、まだ不十分な点があり、前記特許文献１に記載されているような改良技術を適用したところ、偏光フィルムと偏光板保護フィルムとの接着性に改良の余地があるという問題が新たに発見された。 On the other hand, cycloolefin-based polymers are superior to cellulose ester-based polymers in terms of transparency, optical properties, durability, etc. Therefore, polarizing plate protective films using such cycloolefin-based polymers can be used in liquid crystal displays. The demand for use in display devices such as devices is increasing year by year.
However, the protective film of the cycloolefin-based polymer, like the protective film of the cellulose ester-based polymer, is still inadequate in meeting the demand for high performance. As a result of applying the technique, a new problem was discovered that there is room for improvement in the adhesiveness between the polarizing film and the polarizing plate protective film.
特開２００２－３１１２４０号公報Japanese Patent Application Laid-Open No. 2002-311240
　本発明は、上記問題・状況に鑑みてなされたものであり、その解決課題は、ポリビニルアルコール系偏光フィルムとの接着性が改良されたシクロオレフィン系ポリマーを含有する偏光板保護フィルムの製造方法を提供することである。 The present invention has been made in view of the above problems and circumstances, and the problem to be solved is to provide a method for producing a polarizing plate protective film containing a cycloolefin-based polymer having improved adhesion to a polyvinyl alcohol-based polarizing film. to provide.
　本発明者は、上記課題を解決すべく、上記問題の原因等について検討した結果、偏光板保護フィルムの製造の際に、原反フィルム製造工程と加工工程におけるフィルムの搬送速度の相対的関係及び延伸時のフィルム中の残留溶媒の量を一定範囲内に制御すること等により、フィルム表面の状態を改善でき、かつ上記課題を解決できることを見いだし本発明に至った。
　すなわち、本発明に係る上記課題は、以下の手段により解決される。 In order to solve the above problems, the present inventors have investigated the causes of the above problems, etc., and found that when manufacturing a polarizing plate protective film, the relative relationship between the transport speed of the film in the raw film manufacturing process and the processing process. The present inventors have found that the film surface condition can be improved and the above problems can be solved by controlling the amount of residual solvent in the film during stretching within a certain range.
That is, the above problems related to the present invention are solved by the following means.
　１．シクロオレフィン系ポリマーを含有する偏光板保護フィルムの製造方法であって、
　原反フィルム製造工程と加工工程を有し、
　前記原反フィルム製造工程が、少なくとも、ドープを搬送速度Ｖ１にて支持体に流延してウェブを形成する工程と、前記ウェブを流延直後のウェブ幅に対して１段階目の延伸をする工程と、前記ウェブを乾燥して形成されたフィルムを巻き取る工程とからなり、
　前記加工工程が、巻き取られた前記フィルムを、下記式（１）を満たす搬送速度Ｖ２にて搬送し、２段階目の延伸をする工程を有し、
　　式（１）：Ｖ１＜Ｖ２
　さらに、巻き取られたフィルムを、前記２段階目の延伸をする工程にて、巻取り幅に対して前記２段階目の延伸をする直前の残留溶媒量が０．１～０．５質量％の範囲内にて延伸することを特徴とする偏光板保護フィルムの製造方法。 1. A method for producing a polarizing plate protective film containing a cycloolefin polymer, comprising:
It has a raw film manufacturing process and a processing process,
The raw film manufacturing process includes at least a step of casting the dope onto a support at a conveying speed V1 to form a web, and a first-stage stretching of the web width immediately after casting the web. and winding a film formed by drying the web,
The processing step includes a step of conveying the wound film at a conveying speed V2 that satisfies the following formula (1) and performing a second stage stretching,
Formula (1): V 1 < V 2
Furthermore, in the step of stretching the wound film in the second stage, the amount of residual solvent immediately before the second stage stretching with respect to the winding width is 0.1 to 0.5% by mass. A method for producing a polarizing plate protective film, characterized in that stretching is performed within the range of
　２．前記１段階目の延伸をする直前の残留溶媒量が１～１５質量％の範囲内であり、延伸倍率が１．１～２．０倍の範囲内であることを特徴とする第１項に記載の偏光板保護フィルムの製造方法。 2. Item 1, wherein the amount of residual solvent immediately before the first stage stretching is within the range of 1 to 15% by mass, and the stretching ratio is within the range of 1.1 to 2.0 times. A method for producing the described polarizing plate protective film.
　３．前記２段階目の延伸をする工程における延伸倍率が１．１～２．０倍の範囲内であることを特徴とする第１項又は第２項に記載の偏光板保護フィルムの製造方法。 3. 3. The method for producing a polarizing plate protective film according to item 1 or item 2, wherein the stretching ratio in the step of stretching in the second stage is in the range of 1.1 to 2.0 times.
　本発明の上記手段により、ポリビニルアルコール系フィルムとの接着性が改良されたシクロオレフィン系ポリマーを含有する偏光板保護フィルムの製造方法を提供することができる。
　本発明の効果の発現機構ないし作用機構については、明確にはなっていないが、以下のように推察している。 According to the above-described means of the present invention, it is possible to provide a method for producing a polarizing plate protective film containing a cycloolefin-based polymer having improved adhesiveness to a polyvinyl alcohol-based film.
Although the expression mechanism or action mechanism of the effects of the present invention has not been clarified, it is speculated as follows.
　本発明においては、偏光板保護フィルムの製造の際に、原反フィルム製造工程と加工工程におけるフィルムの搬送速度の相対的関係及び延伸時のフィルム中の残留溶媒の量を一定範囲内に制御すること等により、フィルム表面の状態を改善できる。
　すなわち、まず、原反フィルム製造工程において、フィルム（ウェブ）中に溶媒がかなり残留している状態で、１段階目の延伸をすることによってフィルム中のポリマー構成分子、例えばポリマーの分子鎖の配向が表面方向にかたより高密度層を形成することを防ぐことにより、表面の物理化学的状態を接着性の向上に適した状態にすることができたものと推察される。 In the present invention, during the production of the polarizing plate protective film, the relative relationship between the transport speed of the film in the raw film production process and the processing process and the amount of residual solvent in the film during stretching are controlled within a certain range. By doing so, the condition of the film surface can be improved.
That is, first, in the raw film manufacturing process, the polymer constituent molecules in the film (web) are stretched in the first stage with a considerable amount of solvent remaining in the film, such as the orientation of the polymer molecular chains. It is presumed that the physicochemical condition of the surface was made suitable for the improvement of adhesiveness by preventing the formation of a dense layer that was biased in the direction of the surface.
　また、原反フィルム製造工程と加工工程におけるフィルムの搬送速度の相対的関係を前記式（１）を満たすように制御することにより、２段階目の延伸時に、残留溶媒を拡散させ、熱処理による高密度層の生成を抑制することができ、残留溶媒量をある一定の量以下に調整することによって接着剤のフィルムへの浸透量が過剰になることを防ぎ、フィルムの強度が劣化しないようにすることができたと推察される。 In addition, by controlling the relative relationship between the transport speed of the film in the raw film manufacturing process and the processing process so as to satisfy the above formula (1), the residual solvent is diffused during the second stage of stretching, and the high It is possible to suppress the formation of a density layer, and by adjusting the amount of residual solvent to a certain amount or less, it prevents excessive penetration of the adhesive into the film and prevents deterioration of the strength of the film. presumed to have been possible.
　なお、２段階目の延伸で搬送速度と残留溶媒量を制御することによって、接着性を劣化させることがなく延伸フィルムを製造することができる。
　その理由は、２段階目の延伸において、残留溶媒量が０．１～０．５質量％の状態で、フィルムを追加延伸した際には、式（１）に満たす場合においては、延伸工程内で残留溶媒が拡散するため、熱処理による高密度層の生成が抑制されるからであると考えられる。
　一方、式（１）を満たさない場合、すなわちフィルムの搬送速度Ｖ２がＶ１より遅い場合には、延伸工程に入るまでに内部の溶媒が揮発し、追加延伸工程の熱処理によって表層が高密度化されてしまうと考えられる。 By controlling the transport speed and the amount of residual solvent in the second stage of stretching, a stretched film can be produced without deteriorating the adhesiveness.
The reason for this is that in the second stage of stretching, when the film is additionally stretched with a residual solvent amount of 0.1 to 0.5% by mass, if the formula (1) is satisfied, the This is probably because the residual solvent diffuses in the heat treatment, which suppresses the formation of a high-density layer due to the heat treatment.
On the other hand, when the formula ( 1 ) is not satisfied, that is, when the film transport speed V2 is slower than V1, the internal solvent evaporates before entering the stretching step, and the surface layer becomes dense due to the heat treatment in the additional stretching step. It is thought that it will be changed.
本発明の製造工程の流れを示すフローチャートFlowchart showing the flow of the manufacturing process of the present invention 偏光板保護フィルムを製造する装置の概略図Schematic diagram of equipment for manufacturing polarizing plate protective film
　本発明の偏光板保護フィルムの製造方法は、シクロオレフィン系ポリマーを含有する偏光板保護フィルムの製造方法であって、原反フィルム製造工程と加工工程を有し、前記原反フィルム製造工程が、少なくとも、ドープを搬送速度Ｖ１にて支持体に流延してウェブを形成する工程と、前記ウェブを流延直後のウェブ幅に対して１段階目の延伸をする工程と、前記ウェブを乾燥して形成されたフィルムを巻き取る工程とからなり、前記加工工程が、巻き取られた前記フィルムを、下記式（１）を満たす搬送速度Ｖ２にて搬送し、２段階目の延伸をする工程を有し、
　　式（１）：Ｖ１＜Ｖ２
　さらに、巻き取られたフィルムを、前記２段階目の延伸をする工程にて、巻取り幅に対して前記２段階目の延伸をする直前の残留溶媒量が０．１～０．５質量％の範囲内にて延伸することを特徴とする。
　この特徴は、下記各実施態様（形態）に共通する又は対応する技術的特徴である。 A method for producing a polarizing plate protective film of the present invention is a method for producing a polarizing plate protective film containing a cycloolefin-based polymer, comprising a raw film manufacturing step and a processing step, wherein the raw film manufacturing step includes: At least, the steps of casting the dope onto a support at a conveying speed V1 to form a web, stretching the web in the first stage with respect to the width of the web just after casting, and drying the web. In the processing step, the wound film is conveyed at a conveying speed V2 that satisfies the following formula (1), and is stretched in the second stage. having a process
Formula (1): V 1 < V 2
Furthermore, in the step of stretching the wound film in the second stage, the amount of residual solvent immediately before the second stage stretching with respect to the winding width is 0.1 to 0.5% by mass. It is characterized by stretching within the range of.
This feature is a technical feature common to or corresponding to each of the following embodiments (forms).
　本発明の実施態様としては、前記１段階目の延伸をする直前の残留溶媒量が１～１５質量％の範囲内であり、延伸倍率が１．１～２．０倍の範囲内であることがフィルムの接着性向上及びフィルム強度の劣化抑制の観点から好ましい。 As an embodiment of the present invention, the amount of residual solvent immediately before the first stage of stretching is within the range of 1 to 15% by mass, and the stretching ratio is within the range of 1.1 to 2.0 times. is preferable from the viewpoint of improving film adhesion and suppressing deterioration of film strength.
　また、前記２段階目の延伸をする工程における延伸倍率が１．１～２．０倍の範囲内であることが、効果発現の観点からより好ましい。 Further, it is more preferable that the draw ratio in the step of drawing in the second stage is within the range of 1.1 to 2.0 times from the viewpoint of effect expression.
　以下、本発明とその構成要素、及び本発明を実施するための形態・態様について詳細な説明をする。なお、本願において、「～」は、その前後に記載される数値を下限値及び上限値として含む意味で使用する。 The following is a detailed description of the present invention, its components, and the forms and modes for carrying out the present invention. In the present application, "-" is used to mean that the numerical values before and after it are included as the lower limit and the upper limit.
［偏光板保護フィルムの製造方法］
　本発明の偏光板保護フィルムの製造方法は、シクロオレフィン系ポリマーを含有する偏光板保護フィルムの製造方法であって、原反フィルム製造工程と加工工程を有し、前記原反フィルム製造工程が、少なくとも、ドープを搬送速度Ｖ１にて支持体に流延してウェブを形成する工程と、前記ウェブを流延直後のウェブ幅に対して１段階目の延伸をする工程と、前記ウェブを乾燥して形成されたフィルムを巻き取る工程とからなり、前記加工工程が、巻き取られた前記フィルムを、下記式（１）を満たす搬送速度Ｖ２にて搬送し、２段階目の延伸をする工程を有し、
　　式（１）：Ｖ１＜Ｖ２
　さらに、巻き取られたフィルムを、前記２段階目の延伸をする工程にて、巻取り幅に対して前記２段階目の延伸をする直前の残留溶媒量が０．１～０．５質量％の範囲内にて延伸することを特徴とする。
　以下、溶液流延製膜法を用いた製造方法の工程を図１及び図２を参照しながら説明する。 [Method for producing polarizing plate protective film]
A method for producing a polarizing plate protective film of the present invention is a method for producing a polarizing plate protective film containing a cycloolefin-based polymer, comprising a raw film manufacturing step and a processing step, wherein the raw film manufacturing step includes: At least, the steps of casting the dope onto a support at a conveying speed V1 to form a web, stretching the web in the first stage with respect to the width of the web just after casting, and drying the web. In the processing step, the wound film is conveyed at a conveying speed V2 that satisfies the following formula (1), and is stretched in the second stage. having a process
Formula (1): V 1 < V 2
Furthermore, in the step of stretching the wound film in the second stage, the amount of residual solvent immediately before the second stage stretching with respect to the winding width is 0.1 to 0.5% by mass. It is characterized by stretching within the range of.
Hereinafter, steps of a manufacturing method using a solution casting film forming method will be described with reference to FIGS. 1 and 2. FIG.
　図１は、本発明の製造工程の流れを示すフローチャートであり、図２は、偏光板保護フィルムを製造する装置の概略図である。 FIG. 1 is a flow chart showing the flow of the manufacturing process of the present invention, and FIG. 2 is a schematic diagram of an apparatus for manufacturing a polarizing plate protective film.
１．原反フィルム製造工程
　本発明に係る原反フィルムは、溶液流延製膜法で製造されたフィルムであり、原反フィルム製造工程が、少なくとも、ドープを搬送速度Ｖ１にて支持体に流延してウェブを形成する工程、前記ウェブを流延直後のウェブ幅に対して１段階目の延伸をする工程及び前記ウェブを乾燥して形成されたフィルムを巻き取る工程とからなる。 1. Original film manufacturing process The original film according to the present invention is a film manufactured by a solution casting film-forming method, and in the original film manufacturing process, at least the dope is cast onto the support at a conveying speed of V1. forming a web by stretching the web, stretching the web to the width of the web immediately after casting, and drying the web to wind up the film.
　（１．１）ドープを搬送速度Ｖ１にて支持体に流延してウェブを形成する工程
　上記のドープを搬送速度Ｖ１にて支持体に流延してウェブを形成する工程は、少なくともドープ調製工程（Ｓ１）、流延工程（Ｓ２）、及び剥離工程（Ｓ３）とからなる。 (1.1) The step of casting the dope onto a support at a conveying speed V1 to form a web The step of casting the dope onto a support at a conveying speed V1 to form a web includes It consists of a dope preparation step (S1), a casting step (S2), and a stripping step (S3).
　（１．１．１）ドープ調製（撹拌調製）工程（Ｓ１）
　ドープ調製（撹拌調製）工程（Ｓ１）では、撹拌装置１の撹拌槽１ａにて、少なくとも樹脂及び溶媒を攪拌し、支持体３（エンドレスベルト）上に流延するドープを調製する。 (1.1.1) Dope preparation (stirring preparation) step (S1)
In the dope preparation (stirring preparation) step (S1), at least the resin and the solvent are stirred in the stirring tank 1a of the stirring device 1 to prepare the dope to be cast on the support 3 (endless belt).
　以下、本発明の一実施形態として、熱可塑性樹脂であるシクロオレフィン系ポリマー（以下、「ＣＯＰ」ともいう。）を使用する場合を一例としてドープ調製工程を説明する。 Hereinafter, as an embodiment of the present invention, the dope preparation process will be described using a case where a cycloolefin polymer (hereinafter also referred to as "COP"), which is a thermoplastic resin, is used as an example.
　本工程は、シクロオレフィン系ポリマー（ＣＯＰ）に対する良溶媒を主とする溶媒に、溶解釜中で該ＣＯＰ、場合によって、その他の化合物を攪拌しながら溶解しドープを形成する工程、あるいは該ＣＯＰ溶液に、場合によってその他の化合物溶液を混合して主溶解液であるドープを形成する工程である。 This step is a step of dissolving the COP and, in some cases, other compounds in a dissolution tank in a solvent mainly composed of a good solvent for the cycloolefin polymer (COP) while stirring to form a dope, or the COP solution. Then, if necessary, other compound solutions are mixed to form a dope, which is the main solution.
　（シクロオレフィン系ポリマーの濃度）
　ドープ中のシクロオレフィン系ポリマー（ＣＯＰ）の濃度は、濃い方が支持体に流延した後の乾燥負荷が低減できて好ましい。
　ただし、ＣＯＰの濃度が濃過ぎると、ろ過時の負荷が増えて精度が悪くなる。
　これらを両立する濃度としては、１０～３５質量％の範囲内が好ましく、更に好ましくは、１５～３０質量％の範囲内である。 (Concentration of cycloolefin polymer)
The concentration of the cycloolefin polymer (COP) in the dope is preferably as high as possible because the drying load after casting onto the support can be reduced.
However, if the concentration of COP is too high, the load during filtration will increase and the accuracy will deteriorate.
The concentration that satisfies these requirements is preferably in the range of 10 to 35% by mass, more preferably in the range of 15 to 30% by mass.
　（ドープで用いられる溶媒）
　ドープで用いられる溶媒は、単独で用いても二種以上を併用してもよいが、シクロオレフィン系ポリマー（ＣＯＰ）の良溶媒と貧溶媒を混合して使用することが生産効率の点で好ましく、良溶媒が多い方がＣＯＰの溶解性の点で好ましい。 (Solvent used in dope)
The solvent used in the dope may be used alone or in combination of two or more, but it is preferable to use a mixture of a good solvent and a poor solvent for the cycloolefin polymer (COP) from the viewpoint of production efficiency. In view of the solubility of COP, it is preferable to use a large amount of a good solvent.
　良溶媒と貧溶媒の混合比率の好ましい範囲は、良溶媒が７０～９８質量％の範囲内であり、貧溶剤が２～３０質量％の範囲内である。
　本明細書では、「良溶媒」又は「貧溶媒」とは、使用するシクロオレフィン系ポリマー（ＣＯＰ）を単独で溶解するものを良溶媒とし、単独で膨潤するか又は溶解しないものを貧溶媒と定義している。そのため、ＣＯＰの置換基の種類やその数によって良溶媒であるか、又は貧溶媒であるかが変わる可能性がある。 A preferable range of the mixing ratio of the good solvent and the poor solvent is 70 to 98% by mass of the good solvent and 2 to 30% by mass of the poor solvent.
As used herein, the term "good solvent" or "poor solvent" refers to a good solvent that dissolves the cycloolefin polymer (COP) used alone, and a poor solvent that swells or does not dissolve alone. Define. Therefore, depending on the type and number of substituents of COP, it may be a good solvent or a poor solvent.
　本発明に用いられる良溶媒は特に限定されないが、メチレンクロライド等の有機ハロゲン化合物やジオキソラン類、アセトン、酢酸メチル、アセト酢酸メチル等が挙げられる。
　特に好ましくはメチレンクロライド又は酢酸メチルが挙げられる。 Although the good solvent used in the present invention is not particularly limited, organic halogen compounds such as methylene chloride, dioxolanes, acetone, methyl acetate, methyl acetoacetate and the like can be mentioned.
Particularly preferred are methylene chloride and methyl acetate.
　また、本発明に用いられる貧溶媒は特に限定されないが、例えばメタノール、エタノール、ｎ－ブタノール、シクロヘキサン、シクロヘキサノン等が好ましく用いられる。
　また、ドープ中には、水が０．０１～２．００質量％含有されていることが好ましい。 Although the poor solvent used in the present invention is not particularly limited, for example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone and the like are preferably used.
Also, the dope preferably contains 0.01 to 2.00% by mass of water.
　また、シクロオレフィン系ポリマー（ＣＯＰ）の溶解に用いられる溶媒は、偏光板保護フィルム製膜工程で乾燥によりフィルムから除去された溶媒を回収し、これを再利用して用いられる。 In addition, the solvent used for dissolving the cycloolefin polymer (COP) is used by recovering the solvent removed from the film by drying in the process of forming the polarizing plate protective film and reusing it.
　回収溶媒中に、ＣＯＰに添加されている添加剤、例えば可塑剤、紫外線吸収剤、ポリマー、モノマー成分等が微量含有されていることもあるが、これらが含まれていても好ましく再利用することができるし、必要であれば精製して再利用することもできる。 Although the recovery solvent may contain trace amounts of additives added to the COP, such as plasticizers, UV absorbers, polymers, monomer components, etc., even if these are contained, they should preferably be reused. It can be purified and reused if necessary.
　上記記載の、ドープを調製する時のＣＯＰの溶解方法としては、一般的な方法を用いることができる。
　具体的には、常圧で行う方法、主溶媒の沸点以下で行う方法、主溶媒の沸点以上で加圧して行う方法が好ましく、加熱と加圧を組み合わせると常圧における沸点以上に加熱できる。 A general method can be used as the method for dissolving the COP when preparing the dope described above.
Specifically, a method of performing at normal pressure, a method of performing at the boiling point of the main solvent or less, and a method of pressurizing at the boiling point or higher of the main solvent are preferable, and a combination of heating and pressurization enables heating to the boiling point or higher at normal pressure.
　また、溶媒の常圧での沸点以上で、かつ、加圧下で溶媒が沸騰しない範囲の温度で加熱しながら攪拌溶解する方法も、ゲルやママコと呼ばれる塊状未溶解物の発生を防止するため好ましい。 In addition, a method of stirring and dissolving while heating at a temperature above the boiling point of the solvent at normal pressure and within a range in which the solvent does not boil under pressure is also preferable in order to prevent the generation of massive undissolved substances called gels and lumps. .
　また、シクロオレフィン系ポリマー（ＣＯＰ）を貧溶媒と混合して湿潤あるいは膨潤させた後、更に良溶剤を添加して溶解する方法も好ましく用いられる。 A method of mixing a cycloolefin polymer (COP) with a poor solvent to wet or swell it, and then adding a good solvent to dissolve it is also preferably used.
　加圧は窒素ガス等の不活性気体を圧入する方法や、加熱によって溶媒の蒸気圧を上昇させる方法によって行ってもよい。
　加熱は外部から行うことが好ましく、例えばジャケットタイプのものは温度コントロールが容易で好ましい。 Pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or a method of increasing the vapor pressure of the solvent by heating.
Heating is preferably performed from the outside, and for example, a jacket type is preferable because temperature control is easy.
　溶媒を添加しての加熱温度は、高い方がシクロオレフィン系ポリマー（ＣＯＰ）の溶解性の観点から好ましいが、加熱温度が高過ぎると必要とされる圧力が大きくなり生産性が悪くなる。 From the viewpoint of solubility of the cycloolefin-based polymer (COP), a higher heating temperature with the addition of a solvent is preferable, but if the heating temperature is too high, the required pressure increases and productivity deteriorates.
　好ましい加熱温度は３０～１２０℃の範囲内であり、６０～１１０℃の範囲内がより好ましく、７０～１０５℃の範囲内が更に好ましい。
　また、圧力は設定温度で溶媒が沸騰しないように調整される。 The heating temperature is preferably in the range of 30 to 120°C, more preferably in the range of 60 to 110°C, even more preferably in the range of 70 to 105°C.
Also, the pressure is adjusted so that the solvent does not boil at the set temperature.
　又は、冷却溶解法も好ましく用いられ、これによって酢酸メチル等の溶媒にシクロオレフィン系ポリマー（ＣＯＰ）を溶解させることができる。 Alternatively, a cooling dissolution method is also preferably used, whereby the cycloolefin polymer (COP) can be dissolved in a solvent such as methyl acetate.
　（ろ過）
　次に、このシクロオレフィン系ポリマー（ＣＯＰ）溶液（溶解中又は溶解後のドープ）を濾紙等の適当なろ過材を用いてろ過することが好ましい。 (filtration)
Next, it is preferable to filter this cycloolefin-based polymer (COP) solution (dope during or after dissolution) using an appropriate filter medium such as filter paper.
　ろ過材としては、不溶物等を除去するために絶対ろ過精度が小さい方が好ましいが、絶対ろ過精度が小さ過ぎると、ろ過材の目詰まりが発生しやすいという問題がある。
　このため絶対ろ過精度０．００８ｍｍ以下の濾材が好ましく、０．００１～０．００８ｍｍの範囲内の濾材がより好ましく、０．００３～０．００６ｍｍの範囲内の濾材が更に好ましい。 The filter medium preferably has a small absolute filtration accuracy in order to remove insoluble matter and the like.
For this reason, a filter medium with an absolute filtration accuracy of 0.008 mm or less is preferable, a filter medium with an absolute filtration accuracy within the range of 0.001 to 0.008 mm is more preferable, and a filter medium with an absolute filtration accuracy within the range of 0.003 to 0.006 mm is even more preferable.
　濾材の材質は特に制限はなく、通常の濾材を使用することができるが、ポリプロピレン、テフロン（登録商標）等のプラスチック製の濾材や、ステンレススティール等の金属製の濾材が繊維の脱落等がなく好ましい。 There are no particular restrictions on the material of the filter medium, and ordinary filter mediums can be used. preferable.
　ろ過により、原料のシクロオレフィン系ポリマー（ＣＯＰ）に含まれていた不純物、特に輝点異物を除去、低減することが好ましい。 It is preferable to remove and reduce impurities, especially foreign substances with bright spots, contained in the raw material cycloolefin polymer (COP) by filtration.
　輝点異物とは、２枚の偏光板をクロスニコル状態にして配置し、その間にフィルム等を置き、一方の偏光板の側から光を当てて、他方の偏光板の側から観察した時に反対側からの光が漏れて見える点（異物）のことであり、径が、０．０１ｍｍ以上である輝点数が２００個／ｃｍ２以下であることが好ましい。
　より好ましくは１００個／ｃｍ２以下であり、更に好ましくは５０個／ｃｍ２以下であり、更に好ましくは１０個／ｃｍ２以下である。
　また、０．０１ｍｍ以下の輝点も少ない方が好ましい。 A bright spot foreign matter is when two polarizing plates are placed in a crossed Nicols state, a film or the like is placed between them, and light is applied from one polarizing plate side and observed from the other polarizing plate side. It is a point (foreign matter) that looks like light leaking from the side, and the number of bright spots with a diameter of 0.01 mm or more is preferably 200/cm 2 or less.
It is more preferably 100/cm 2 or less, still more preferably 50/cm 2 or less, still more preferably 10/cm 2 or less.
Also, it is preferable that the number of bright spots of 0.01 mm or less is small.
　ドープのろ過は通常の方法で行うことができるが、溶媒の常圧での沸点以上で、かつ加圧下で溶媒が沸騰しない範囲の温度で加熱しながらろ過する方法が、ろ過前後の濾圧の差（差圧という）の上昇が小さく、好ましい。 Filtration of the dope can be carried out by an ordinary method, but a method of filtering while heating at a temperature above the boiling point of the solvent at normal pressure and within a range in which the solvent does not boil under pressure is preferred because the filtration pressure before and after filtration is reduced. It is preferable because the difference (referred to as differential pressure) is small.
　好ましい温度は３０～１２０℃の範囲内であり、４５～７０℃の範囲内がより好ましく、４５～５５℃の範囲内であることが更に好ましい。 The temperature is preferably in the range of 30-120°C, more preferably in the range of 45-70°C, even more preferably in the range of 45-55°C.
　濾圧は小さい方が好ましい。
　具体的には１．６ＭＰａ以下であることが好ましく、１．２ＭＰａ以下であることがより好ましく、１．０ＭＰａ以下であることが更に好ましい。 The smaller the filtering pressure, the better.
Specifically, it is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and even more preferably 1.0 MPa or less.
　（１．１．２）流延工程（Ｓ２）
　流延工程（Ｓ２）では、搬送速度Ｖ１で支持体３上に流延されたドープにより形成されたウェブ５を、支持体３上で加熱し、支持体３から剥離ローラー４によってウェブ５が剥離可能になるまで溶媒を蒸発させる。
　そして、上記の溶媒の蒸発によって１段階目の延伸をする直前の残留溶媒量を制御する。 (1.1.2) Casting step (S2)
In the casting step (S2), the web 5 formed by the dope cast on the support 3 at the conveying speed V1 is heated on the support 3, and the web 5 is separated from the support 3 by the peeling roller 4. Evaporate the solvent until it can be peeled off.
Then, the amount of residual solvent immediately before the first stage of stretching is controlled by evaporation of the solvent.
　上記の蒸発は、５～７５℃の範囲内の雰囲気下行うことが好ましい。
　溶媒を蒸発させるには、温風をウェブ上面に当てる方法や及び／又は支持体３の裏面から液体により伝熱させる方法、及び輻射熱により表裏から伝熱する方法等があるが、輻射熱により表裏から伝熱する方法が、乾燥効率が良く好ましい。
　また、それらを組み合わせる方法も好ましく用いられる。 The above evaporation is preferably carried out in an atmosphere within the range of 5 to 75°C.
To evaporate the solvent, there are a method of applying hot air to the upper surface of the web and/or a method of transferring heat from the back surface of the support 3 with a liquid, and a method of transferring heat from the front and back by radiant heat. A heat transfer method is preferred because of its high drying efficiency.
Moreover, the method of combining them is also preferably used.
　流延（キャスト）の幅は、生産性の観点から１．３ｍ以上が好ましい。
　より好ましくは１．３～４．０ｍの範囲内である。
　流延（キャスト）の幅が４．０ｍを超えなければ、製造工程で縞が入らず、その後の搬送工程での安定性が高くなる。
　搬送性、生産性の観点では、１．３～３．０ｍの範囲内がさらに好ましい。 The casting width is preferably 1.3 m or more from the viewpoint of productivity.
More preferably, it is within the range of 1.3 to 4.0 m.
If the casting width does not exceed 4.0 m, streaks will not occur in the manufacturing process, and the stability in the subsequent transport process will be high.
From the viewpoint of transportability and productivity, the range of 1.3 to 3.0 m is more preferable.
　流延（キャスト）工程（Ｓ２）における支持体３は、表面を鏡面仕上げしたものが好ましく、支持体３としては、ステンレススティールベルト若しくは鋳物で表面をメッキ仕上げしたドラムが好ましく用いられる。 The support 3 in the casting step (S2) preferably has a mirror-finished surface, and as the support 3, a stainless steel belt or a casting drum with a plated surface is preferably used.
　流延工程（Ｓ２）の支持体３の表面温度は－５０℃～溶媒の沸点の範囲内の温度で、温度が高い方がウェブの乾燥速度が速くできるので好ましい。 The surface temperature of the support 3 in the casting step (S2) is within the range of -50°C to the boiling point of the solvent.
　好ましい支持体温度は０～５５℃の範囲内であり、２２～５０℃の範囲内が更に好ましい。 The support temperature is preferably in the range of 0 to 55°C, more preferably in the range of 22 to 50°C.
　支持体３の温度を制御する方法は特に制限されないが、温風又は冷風を吹きかける方法や、温水を支持体の裏側に接触させる方法がある。
　温水を用いる方が熱の伝達が効率的に行われるため、支持体の温度が一定になるまでの時間が短く好ましい。
　温風を用いる場合は目的の温度よりも高い温度の風を使う場合がある。 A method for controlling the temperature of the support 3 is not particularly limited, but there are a method of blowing hot or cold air and a method of contacting the back side of the support with hot water.
The use of hot water is preferable because it takes less time to reach a constant temperature of the support because heat is transferred more efficiently.
When using hot air, the air may have a higher temperature than the target temperature.
　流延工程（Ｓ２）では、ドープ調製工程（Ｓ１）で調製されたドープを、加圧型定量ギアポンプ等を通して、導管によって流延ダイ２に送液し、無限に移送する回転駆動ステンレス鋼製エンドレスベルトよりなる支持体３上の流延位置に流延ダイ２からドープを流延する。 In the casting step (S2), the dope prepared in the dope preparation step (S1) is sent through a pressurized constant gear pump or the like to the casting die 2 through a conduit, and is transported endlessly by a rotary driven stainless steel endless belt. A dope is cast from a casting die 2 onto a casting position on a support 3 made of the dope.
　ここで、流延ダイスリットのドープの出るところをリップと呼ぶが、リップ部分のスリット形状を調整することができ、膜厚を均一にしやすい流延ダイが好ましい。
　流延ダイには、コートハンガーダイやＴダイ等があるが、いずれも好ましく用いられる。
　なお、本発明において、「ウェブ」とは、上記のリップ部分から流延されるドープ膜のことをいう。
　原反フィルムの製膜速度を上げるために、上記の流延ダイを支持体上に２基以上設け、ドープ量を分割して重層してもよい。
　あるいは複数のドープを同時に流延する共流延法によって積層構造の原反フィルムを得ることも好ましい。 Here, the portion of the casting die slit where the dope comes out is called a lip, and a casting die is preferable because the slit shape of the lip portion can be adjusted and the film thickness can be easily made uniform.
Casting dies include coat hanger dies, T dies, and the like, and all of them are preferably used.
In the present invention, the term "web" refers to the dope film cast from the lip portion.
In order to increase the production speed of the raw film, two or more of the above-mentioned casting dies may be provided on the support, and the dope amount may be divided for layering.
Alternatively, it is also preferable to obtain a raw film having a laminated structure by a co-casting method in which a plurality of dopes are simultaneously cast.
　スリットはヒートボルトを手動で回して押し込むことで狭めたりして膜厚を薄くしたり、逆に開いて厚くしたりもする。
　ヒートボルトに電圧をかけることで、熱による押し込みをする方式も一般的であるが、通常は組み合わせて使用する。
　また、押し引きをする方式をとることも可能である。
　ただし、ボルトのピッチが流延ダイの機構上、狭く出来なかったりすることがあり、粘度が高いドープ（溶融含む）の場合は流延ダイ吐出時のリップに圧力負荷が大きく、吐出後負荷が急激に低下して膜厚が大きくなったりする（バラス効果）といった幅手膜厚にバラつきが生じることがある。
　従って、流延ダイ内部の構造により流延ダイのリップに負荷がかかり過ぎないような設計が必要となる。 The slit can be narrowed by manually turning and pushing the heat bolt to make the film thinner, or conversely, it can be opened to make it thicker.
It is also common to apply a voltage to the heat bolt to push it in by heat, but it is usually used in combination.
It is also possible to adopt a method of pushing and pulling.
However, due to the mechanism of the casting die, it may not be possible to narrow the pitch of the bolts, and in the case of dope with high viscosity (including melted), the pressure load on the lip when the casting die is discharged is large, and the load after discharge is increased. In some cases, the width of the film thickness varies, such as a rapid decrease and an increase in the film thickness (balus effect).
Therefore, it is necessary to design the lip of the casting die so that the internal structure of the casting die does not apply too much load.
　流延工程（Ｓ２）では、搬送速度Ｖ１にて流延したドープを支持体３上で乾燥させて、ウェブ５を形成する。
　その際、流延ダイ２の傾き、すなわち流延ダイ２から支持体３へのドープの吐出方向は、支持体３の面（ドープが流延される面）の法線に対する角度で０～９０°の範囲内となるように適宜設定されればよい。 In the casting step ( S<b>2 ), the dope cast at the conveying speed V 1 is dried on the support 3 to form the web 5 .
At this time, the inclination of the casting die 2, that is, the direction in which the dope is discharged from the casting die 2 to the support 3 is an angle of 0 to 90 with respect to the normal to the surface of the support 3 (the surface on which the dope is cast). ° may be set as appropriate.
　支持体３は、例えばステンレスベルトで構成され、一対のローラー３ａ、３ｂ及びこれらの間に位置する複数のローラーによって保持されている。
　このとき、支持体の表面は鏡面となっていることが好ましい。 The support 3 is made of, for example, a stainless steel belt and held by a pair of rollers 3a and 3b and a plurality of rollers positioned therebetween.
At this time, the surface of the support is preferably a mirror surface.
　ローラー３ａ及び３ｂの一方、又は両方には、支持体３に張力を付与する駆動装置が設けられており、これによって支持体３は張力が掛けられて張った状態で使用される。
　なお、支持体３は、ドラムであってもよい。 One or both of the rollers 3a and 3b are provided with a drive for applying tension to the support 3, whereby the support 3 is used under tension.
Note that the support 3 may be a drum.
　（１．１．３）剥離工程（Ｓ３）
　本工程では、流延工程（Ｓ２）にて、支持体３上でウェブ５が剥離可能な膜強度となるまで溶媒を蒸発させ、乾燥固化あるいは冷却凝固させた後、支持体３を原反フィルムが一周する前にウェブを支持体３から剥離する。
　すなわち、本工程は支持体３上で溶媒が蒸発したウェブを、剥離位置で剥離する工程である。
　このとき、面品質、透湿性、剥離性の観点から、３０～６００秒の範囲内で原反フィルムを支持体から剥離することが好ましい。
　なお、支持体からウェブを剥離する位置のことを剥離点といい、また、剥離を助けるロールを剥離ローラーという。
　剥離工程（Ｓ３）では、ウェブを、自己支持性を持たせたまま剥離ローラー４によって剥離する。
　支持体上の剥離位置における温度は－５０～４０℃の範囲内とするのが好ましく、１０～４０℃の範囲内がより好ましく、１５～３０℃の範囲内とするのが最も好ましい。 (1.1.3) Peeling step (S3)
In this step, in the casting step (S2), the solvent is evaporated on the support 3 until the film strength becomes such that the web 5 can be peeled off. strips the web from the support 3 before it makes one turn.
That is, this step is a step of peeling off the web from which the solvent has evaporated on the support 3 at the peeling position.
At this time, from the viewpoint of surface quality, moisture permeability, and releasability, it is preferable to release the base film from the support within 30 to 600 seconds.
The position where the web is peeled off from the support is called the peeling point, and the roll that assists the peeling is called the peeling roller.
In the peeling step (S3), the web is peeled off by the peeling roller 4 while maintaining self-supporting properties.
The temperature at the peeling position on the support is preferably in the range of -50 to 40°C, more preferably in the range of 10 to 40°C, most preferably in the range of 15 to 30°C.
　（残留溶媒量）
　１段階目の延伸をする直前の残留溶媒量は、乾燥の条件の強弱、支持体３の長さ等によって適宜調節される。
　ウェブの厚さにもよるが、剥離点での残留溶媒量が多すぎるとウェブが柔らか過ぎて剥離しにくくなることがあり、平面性を損なったり、剥離張力による横段、ツレや縦スジが発生しやすくなることがある。
　逆に、残留溶媒量が少なすぎると、途中でウェブの一部が剥がれたりすることがある。
　ウェブが良好な平面性を示すためには、経済速度と品質との兼ね合いの観点から残留溶媒量が１～５０質量％の範囲内であることが好ましい。
　また、本発明の効果発現の観点からは、１～１５質量％の範囲内であることが好ましい。 (Residual solvent amount)
The amount of residual solvent immediately before the first stage of stretching is appropriately adjusted depending on the strength of the drying conditions, the length of the support 3, and the like.
Although it depends on the thickness of the web, if the amount of residual solvent at the peeling point is too large, the web may be too soft and difficult to peel off, resulting in loss of flatness, horizontal steps, creases, and vertical streaks due to peeling tension. It may occur more easily.
Conversely, if the amount of residual solvent is too small, the web may partially peel off during the process.
In order for the web to exhibit good flatness, the amount of residual solvent is preferably in the range of 1 to 50% by mass from the viewpoint of balancing economic speed and quality.
Also, from the viewpoint of exhibiting the effect of the present invention, it is preferably in the range of 1 to 15% by mass.
　製膜速度を上げる方法（残留溶媒量ができるだけ多いうちに剥離するため製膜速度を上げることができる）として、残留溶媒量が多くとも剥離できるゲル流延法（ゲルキャスティング）がある。
　その方法としては、ドープ中にシクロオレフィン系ポリマー（ＣＯＰ）に対する貧溶媒を加えて、ドープ流延後、ウェブをゲル化する方法、支持体を冷却することによってウェブをゲル化させて残留溶媒を多く含んだ状態で剥離する方法等がある。
　また、ドープ中に金属塩を加える方法もある。
　上記のように、支持体上でウェブをゲル化させ、膜を強くすることによって剥離を早め、製膜速度を上げることができる。 As a method for increasing the film-forming speed (the film-forming speed can be increased because the film is peeled off while the amount of residual solvent is as large as possible), there is a gel casting method that allows the film to be peeled off even when the amount of residual solvent is large.
The method includes adding a poor solvent for the cycloolefin polymer (COP) to the dope, gelling the web after dope casting, and cooling the support to gel the web and remove the residual solvent. There is a method of exfoliating in a state containing a large amount.
There is also a method of adding a metal salt to the dope.
As described above, by gelling the web on the support and strengthening the film, peeling can be accelerated and the film production speed can be increased.
　なお、残留溶媒量は、下記式で定義される。
　　残留溶媒量（質量％）＝｛（Ｍ－Ｎ）／Ｎ｝×１００
　なお、Ｍはウェブ又は偏光板保護フィルムを製造中又は製造後の任意の時点で採取した試料の質量で、ＮはＭを１１５℃で１時間の加熱後の質量である。 The amount of residual solvent is defined by the following formula.
Residual solvent amount (mass%) = {(MN) / N} × 100
In addition, M is the mass of a sample taken at an arbitrary point during or after the production of the web or polarizing plate protective film, and N is the mass after heating M at 115° C. for 1 hour.
　（残留溶媒量の測定方法）
　残留溶媒量は、ヘッドスペースガスクロマトグラフィーにより測定することができる。
　ヘッドスペースガスクロマトグラフィー法では、試料を容器に封入し、加熱し、容器中に揮発成分が充満した状態で速やかに容器中のガスをガスクロマトグラフに注入し、質量分析を行って化合物の同定を行いながら揮発成分を定量するものである。
　ヘッドスペース法では、ガスクロマトグラフにより、揮発成分の全ピークを観測することを可能にするとともに、電磁気的相互作用を利用した分析法を用いることによって、高精度で揮発性物質やモノマーなどの定量も併せて行うことができる。 (Method for measuring residual solvent amount)
The amount of residual solvent can be measured by headspace gas chromatography.
In the headspace gas chromatography method, the sample is sealed in a container, heated, and with the container filled with volatile components, the gas in the container is quickly injected into the gas chromatograph, and mass spectrometry is performed to identify the compound. Volatile components are quantified while the measurement is being carried out.
The headspace method makes it possible to observe all peaks of volatile components by gas chromatograph, and quantifies volatile substances and monomers with high accuracy by using an analytical method that uses electromagnetic interaction. It can be done together.
　（剥離張力）
　支持体とウェブを剥離する際の剥離張力は、３００Ｎ／ｍ以下とすることが好ましい。
　より好ましくは、１９６～２４５Ｎ／ｍの範囲内であるが、剥離の際に皺が入りやすい場合、１９０Ｎ／ｍ以下の張力で剥離することが好ましい。 (Peel tension)
The peeling tension when peeling the support from the web is preferably 300 N/m or less.
More preferably, the tension is in the range of 196 to 245 N/m, but if wrinkles are likely to occur during peeling, it is preferable to peel with a tension of 190 N/m or less.
　（１．２）ウェブを流延直後のウェブ幅に対して１段階目の延伸をする工程
　この工程は、１段階目の延伸をする工程（Ｓ４）であり、支持体から剥離後のウェブを搬送方向（Ｍａｃｈｉｎｅ　Ｄｉｒｅｃｔｉｏｎ、以下「ＭＤ方向」ともいう。）に延伸することによって行われる。
　この場合、ウェブは、ウェブ面内でＭＤ方向と直交する幅手方向（Ｔｒａｖｅｒｓｅ　Ｄｉｒｅｃｔｉｏｎ、以下「ＴＤ方向」ともいう。）に収縮する。
　延伸は、求められる光学特性に応じて行えばよく、少なくとも一方の方向に延伸することが好ましく、互いに直交する二方向に延伸（例えば、膜状物の幅手方向（ＴＤ方向）と、それと直交する搬送方向（ＭＤ方向）の二軸延伸）してもよい。
　延伸倍率は、（延伸後のフィルムの延伸方向大きさ）／（延伸前のフィルムの延伸方向大きさ）として定義される。
　なお、二軸延伸を行う場合は、ＴＤ方向とＭＤ方向のそれぞれについて、延伸倍率を１．１～２．０倍の範囲内とすることが好ましい。 (1.2) Step of first-stage stretching of the web width immediately after casting This step is the step of first-stage stretching (S4), and the web is peeled off from the support. It is carried out by stretching in the machine direction (hereinafter also referred to as "MD direction").
In this case, the web shrinks in the transverse direction (traverse direction, hereinafter also referred to as "TD direction") orthogonal to the MD direction within the web surface.
The stretching may be carried out depending on the required optical properties, preferably in at least one direction, and in two directions perpendicular to each other (for example, the width direction (TD direction) of the film and the direction perpendicular to it). Biaxial stretching in the transport direction (MD direction) may be performed.
The draw ratio is defined as (stretching direction size of the film after stretching)/(stretching direction size of the film before stretching).
In the case of biaxial stretching, the stretching ratio is preferably in the range of 1.1 to 2.0 in both the TD and MD directions.
　（残留溶媒量）
　本発明における１段階目の延伸をする直前の残留溶媒量とは、前述した剥離工程（Ｓ３）の剥離点での残留溶媒量と同義である。
　本発明の実施態様としては、前記１段階目の延伸をする直前の残留溶媒量が１～１５質量％の範囲内であり、延伸倍率が１．１～２．０倍の範囲内であることがフィルムの接着性向上及びフィルム強度の劣化抑制の観点から好ましい。 (Residual solvent amount)
The residual solvent amount immediately before the first stage of stretching in the present invention is synonymous with the residual solvent amount at the peeling point in the peeling step (S3) described above.
As an embodiment of the present invention, the amount of residual solvent immediately before the first stage of stretching is within the range of 1 to 15% by mass, and the stretching ratio is within the range of 1.1 to 2.0 times. is preferable from the viewpoint of improving film adhesion and suppressing deterioration of film strength.
　前記１段階目の延伸をする工程（Ｓ４）によって、ウェブ厚さ方向におけるポリマー分子（マトリックス分子）間の絡み合いが促進されることにより、偏光板作製時に、偏光板保護フィルムを偏光子層と接着剤を介して接着する場合でも、上記接着剤がマトリックス分子間の絡み合いの部分（架橋部分）を介して偏光板保護フィルム内部に浸透しやすくなる。
　その結果、偏光板保護フィルムを、接着剤を介して偏光子層（「偏光フィルム」、「偏光子フィルム」又は「偏光子膜」ともいう。）に強固に固定することができ、偏光子層に対する偏光板保護フィルムの剥離強度を向上させることができる。
　つまり、偏光板保護フィルムと偏光子層との接着性が向上し、フィルム強度の劣化抑制機能を確保することできる。 The first-stage stretching step (S4) promotes entanglement between polymer molecules (matrix molecules) in the thickness direction of the web. Even in the case of bonding via an agent, the adhesive easily permeates into the polarizing plate protective film via the entangled portions (crosslinked portions) between matrix molecules.
As a result, the polarizing plate protective film can be firmly fixed to the polarizer layer (also referred to as "polarizing film", "polarizer film" or "polarizer film") via the adhesive, and the polarizer layer It is possible to improve the peel strength of the polarizing plate protective film against.
That is, the adhesiveness between the polarizing plate protective film and the polarizer layer is improved, and the function of suppressing deterioration of film strength can be ensured.
　前記１段階目の延伸をする工程（Ｓ４）では、ウェブを幅手方向に収縮させる。
　ウェブを収縮させる方法としては、例えば（１）ウェブを幅手保持しない状態で高温処理して、ウェブの密度を高める、（２）ウェブに対して搬送方向（ＭＤ方向）に張力をかけて、ウェブを幅手方向（ＴＤ方向）に収縮させる、及び（３）急峻にウェブの残留溶媒量を減少させる、等の方法がある。 In the first step of stretching (S4), the web is shrunk in the width direction.
As a method for shrinking the web, for example, (1) the web is subjected to a high temperature treatment without being held widthwise to increase the density of the web; There are methods such as shrinking the web in the width direction (TD direction) and (3) sharply reducing the amount of residual solvent in the web.
　（１．３）ウェブを乾燥して形成されたフィルムを巻き取る工程
　この工程は、乾燥工程（Ｓ５）、第１切断工程（Ｓ６）及び第１巻取工程（Ｓ７）からなる。
　なお、前記ドープ調製工程（Ｓ１）におけるドープの搬送速度Ｖ１と上記の第１巻取工程（Ｓ７）における巻取速度とは同一の速度である。
　また、上記において、「搬送速度と巻取り速度とは同一の速度」とは、厳密にいえば±１０％の範囲内において同一であることをいうものとする。 (1.3) Step of drying the web and winding up the film formed This step consists of a drying step (S5), a first cutting step (S6) and a first winding step (S7).
The dope transport speed V1 in the dope preparing step (S1) and the winding speed in the first winding step (S7) are the same speed.
Moreover, in the above description, "the conveying speed and the winding speed are the same speed" strictly speaking means that they are the same within a range of ±10%.
　（１．３．１）乾燥工程（Ｓ５）
　乾燥工程（Ｓ５）は、ウェブを支持体上で加熱し、溶媒を蒸発させ、形成されたフィルムを巻き取る工程である。 (1.3.1) Drying step (S5)
The drying step (S5) is a step of heating the web on the support, evaporating the solvent, and winding up the formed film.
　図２における乾燥装置７内では、側面から見て千鳥状に配置された複数の搬送ローラーによってウェブが搬送され、その間にウェブが乾燥される。 In the drying device 7 in FIG. 2, the web is transported by a plurality of transport rollers arranged in a zigzag pattern when viewed from the side, and the web is dried in the meantime.
　乾燥装置７での乾燥方法は、特に制限はなく、一般的に熱風、赤外線、加熱ローラー、マイクロ波等を用いてウェブを乾燥させるが、簡便さの点から、熱風でウェブを乾燥させる方法が好ましい。
　また、それらを組み合わせる方法も好ましい。
　なお、乾燥工程（Ｓ５）は、必要に応じて行われればよい。 The drying method in the drying device 7 is not particularly limited, and hot air, infrared rays, heating rollers, microwaves, etc. are generally used to dry the web. preferable.
Moreover, the method of combining them is also preferable.
In addition, the drying step (S5) may be performed as necessary.
　ウェブの膜厚が薄ければ乾燥が早いが、あまり急激な乾燥は、出来上がりのフィルムの平面性を損ねやすい。
　高温による乾燥を行う際には、残留溶媒量を考慮する必要があるが、残留溶媒量は、多すぎないことで溶媒の発泡による故障を防ぐことができる。
　全体を通して乾燥はおおむね３０～２５０℃の範囲内で行われる。
　特に３５～２００℃の範囲内で乾燥させることが好ましく、乾燥温度は、段階的に高くしていくことが好ましい。 If the film thickness of the web is thin, it dries quickly, but too rapid drying tends to impair the flatness of the finished film.
When drying at a high temperature, it is necessary to consider the amount of residual solvent, but if the amount of residual solvent is not too large, failure due to foaming of the solvent can be prevented.
Drying is generally carried out in the range of 30-250° C. throughout.
In particular, it is preferable to dry within the range of 35 to 200° C., and it is preferable to increase the drying temperature stepwise.
　支持体の温度は、全体が同じでも、位置によって異なっていてもよい。 The temperature of the support may be the same throughout or may vary depending on the position.
　ウェブの乾燥工程では、一般にローラー乾燥方式（上下に配置した多数のローラーにウェブを交互に通し乾燥させる方式）やテンター方式でウェブを搬送させながら乾燥する方式が採られる。 In the web drying process, a roller drying method (a method in which the web is alternately passed through a number of rollers arranged above and below to dry it) and a tenter method are used to dry the web while it is transported.
　テンター延伸装置を用いる場合は、後述する延伸工程においてテンター延伸装置の左右把持手段によってウェブの把持長（把持開始から把持終了までの距離）を左右で独立に制御できる装置を用いることが好ましい。 When a tenter stretching device is used, it is preferable to use a device that can independently control the left and right gripping lengths of the web (the distance from the start of gripping to the end of gripping) by left and right gripping means of the tenter stretching device in the stretching step described later.
　（１．３．２）第１切断工程（Ｓ６）
　第１切断工程（Ｓ６）では、スリッターからなる切断部８が、１段階目の延伸をする工程（Ｓ４）によって延伸され、乾燥工程（Ｓ５）を経たフィルムＦの幅手方向の両端部を切断する。
　フィルムＦにおいて、両端部の切断後に残った部分は、フィルム製品となる製品部を構成する。
　一方、フィルムＦから切断された部分は、回収され、再び原材料の一部として偏光板保護フィルムの製膜に再利用してもよい。 (1.3.2) First cutting step (S6)
In the first cutting step (S6), the cutting section 8 made of a slitter is stretched in the step of stretching in the first stage (S4), and the both ends in the width direction of the film F that has undergone the drying step (S5) are cut. do.
In the film F, the portion remaining after the cutting of both ends constitutes the product portion which will be the film product.
On the other hand, the portion cut from the film F may be recovered and reused as part of the raw material for forming the polarizing plate protective film.
　（１．３．３）第１巻取工程（Ｓ７）
　第１巻取工程（Ｓ７）にて、フィルムＦを、搬送速度Ｖ１（巻取速度Ｖ１）にて巻取装置９によって巻取り、原反フィルム製造工程が完了する。
　巻取工程におけるフィルムＦを巻取る際の初期張力の好ましい範囲は、２０～３００Ｎ／ｍの範囲内である。 (1.3.3) First Winding Step (S7)
In the first winding step (S7), the film F is wound by the winding device 9 at the conveying speed V 1 (winding speed V 1 ), and the original film manufacturing step is completed.
A preferable range of the initial tension when winding the film F in the winding process is in the range of 20 to 300 N/m.
２．加工工程
　加工工程は、巻き取られた前記フィルムを、そのロール体から繰り出される工程（Ｓ８）を経て、下記式（１）を満たす搬送速度Ｖ２にて搬送し、２段階目の延伸をする工程であり、少なくとも繰り出し工程（Ｓ８）、２段階目の延伸行程（Ｓ９）、第２切断工程（Ｓ１０）、及び第２巻取工程（Ｓ１１）とからなる。
　　式（１）Ｖ１＜Ｖ２ 2. Processing step In the processing step, the wound film is conveyed at a conveying speed V2 that satisfies the following formula (1) through the step (S8) of unwinding from the roll body, and is stretched in the second stage. It consists of at least a feeding step (S8), a second drawing step (S9), a second cutting step (S10), and a second winding step (S11).
Formula (1) V 1 < V 2
　（残留溶媒量）
　本発明の製造方法において、２段階目の延伸をする直前の残留溶媒量は、０．１～０．５質量％の範囲内である。 (Residual solvent amount)
In the production method of the present invention, the amount of residual solvent immediately before the second stage of stretching is in the range of 0.1 to 0.5% by mass.
　（２．１）２段階目の延伸工程（Ｓ９）
　２段階目の延伸工程（Ｓ９）は、フィルムをフィルム面内でＭＤ方向にのみ延伸する工程であってもよいし、ＴＤ方向にのみ延伸する工程であってもよいし、ＭＤ方向及びＴＤ方向の両方に対してであってもよいし、斜め方向に延伸する工程であってもよい。
　また、延伸方向に限定はないが、広幅のフィルムを得る観点では、少なくとも幅手方向の延伸を含む工程があることが好ましい。
　このような延伸は、延伸装置１０を用いて行うことができる。 (2.1) Second stage stretching step (S9)
The second stage stretching step (S9) may be a step of stretching the film only in the MD direction within the film plane, may be a step of stretching only in the TD direction, or may be a step of stretching in the MD direction and the TD direction. , or may be a step of stretching in an oblique direction.
In addition, the stretching direction is not limited, but from the viewpoint of obtaining a wide film, it is preferable that there is a step including at least stretching in the lateral direction.
Such stretching can be performed using a stretching device 10 .
　高位相差確保、広幅確保、及び偏光フィルムと接着の際の接着剤浸透促進のためには、２段階目の延伸工程においてフィルムを高倍率で延伸することが好ましい。
　ただし、延伸倍率が高すぎると、延伸応力により、フィルム内にクレーズが発生したり、フィルム強度を保っているマトリックス分子間の絡み合いが解離して、フィルムが脆弱化する場合があり得る。 In order to secure a high retardation, secure a wide width, and promote the permeation of the adhesive when bonding to the polarizing film, it is preferable to stretch the film at a high magnification in the second stage of the stretching process.
However, if the draw ratio is too high, the drawing stress may cause crazes in the film, or the entanglement between matrix molecules that maintain the film strength may be dissociated, thereby weakening the film.
　このため、２段階目の延伸工程における延伸倍率は、１．１～２．０倍の範囲内であることが本発明の効果発現の観点からより好ましい。 Therefore, it is more preferable that the draw ratio in the second-stage drawing process is in the range of 1.1 to 2.0 times from the viewpoint of manifesting the effects of the present invention.
　なお、本発明のように、剥離工程後の延伸や２段階目の延伸行程における延伸等、延伸が複数回行われる場合、複数回の延伸のうちでマトリックス分子の解離のリスクが最も高い最高倍率の延伸は、最終回に行われることが好ましい。
　そのため、本発明においては、２段階目の延伸行程にて最高倍率の延伸が行われることが好ましい。
　この場合、最高倍率の延伸までに、マトリックス分子の絡み合いを強固にできるため、最高倍率の延伸を行っても、マトリックス分子の絡み合いの解離を抑えて、凝集破壊を抑えることができる。 As in the present invention, when the stretching is performed multiple times, such as the stretching after the peeling process or the stretching in the second stage of the stretching process, the highest magnification at which the risk of dissociation of the matrix molecules is the highest among the multiple stretchings. It is preferable that the drawing be performed at the final time.
Therefore, in the present invention, it is preferable that the stretching at the highest magnification is performed in the second stage of the stretching process.
In this case, since the entanglement of the matrix molecules can be strengthened before the stretching at the maximum magnification, the dissociation of the entanglement of the matrix molecules can be suppressed and cohesive failure can be suppressed even when the stretching at the maximum magnification is performed.
　２段階目の延伸工程（Ｓ９）では、フィルムＦを延伸装置１０によって延伸する。
　このときの延伸方法としては、ローラーの周速差を設けて搬送方向（フィルムの長手方向；製膜方向；流延方向；ＭＤ方向）に延伸する方式や、フィルムの両側縁部をクリップ等で固定して幅手方向（フィルム面内で直交する方向；ＴＤ方向）に延伸するテンター方式が、フィルムの性能・生産性、平面性や寸法安定性を向上させるために好ましい。 In the second-stage stretching step (S9), the film F is stretched by the stretching device 10. As shown in FIG.
As a stretching method at this time, a method of stretching in the conveying direction (longitudinal direction of the film; film forming direction; casting direction; MD direction) by providing a peripheral speed difference between rollers; A tenter system in which the film is fixed and stretched in the width direction (the direction perpendicular to the plane of the film; TD direction) is preferable in order to improve the performance, productivity, flatness and dimensional stability of the film.
　また、いわゆるテンター法の場合、リニアドライブ方式でクリップ部分を駆動すると滑らかな延伸を行うことができ、破断等の危険性が減少できるので好ましい。 In addition, in the case of the so-called tenter method, it is preferable to drive the clip portion by a linear drive method, since smooth stretching can be performed and the risk of breakage can be reduced.
　製膜工程のこれらの幅保持あるいは横方向の延伸はテンター延伸装置によって行うことが好ましく、ピンテンターでもクリップテンターでもよい。
　なお、延伸装置１０内では、延伸に加えて乾燥を行ってもよい。 Width retention and lateral stretching in the film-forming process are preferably carried out by a tenter-stretching device, which may be a pin tenter or a clip tenter.
In the stretching device 10, drying may be performed in addition to stretching.
　（２．２）第２切断工程（Ｓ１０）
　第２切断工程（Ｓ１０）では、スリッターからなる切断部１１が、２段階目の延伸工程（Ｓ９）によって延伸されたフィルムＦの幅手方向の両端部を切断する。
　フィルムＦにおいて、両端部の切断後に残った部分は、フィルム製品となる製品部を構成する。
　一方、フィルムＦから切断された部分は、回収され、再び原材料の一部としてフィルムの製膜に再利用してもよい。 (2.2) Second cutting step (S10)
In the second cutting step (S10), the cutting section 11 made of a slitter cuts both ends in the width direction of the film F stretched in the second stretching step (S9).
In the film F, the portion remaining after the cutting of both ends constitutes the product portion which will be the film product.
On the other hand, the portion cut from the film F may be recovered and reused as part of the raw material for forming the film.
　（２．３）第２巻取工程（Ｓ１１）
　第２巻取工程（Ｓ１１）にて、フィルムＦを、搬送速度Ｖ２にて巻取装置１２によって巻取る。
　なお、このとき、フィルムの厚さは、５～１００μｍの範囲内が好ましく、より好ましくは５～８０μｍの範囲内であり、５～４０μｍの範囲内がさらに好ましい。
　第２巻取工程（Ｓ１１）におけるフィルムＦを巻取る際の初期張力の好ましい範囲は、２０～３００Ｎ／ｍの範囲内である。 (2.3) Second Winding Step (S11)
In the second winding step (S11), the film F is wound by the winding device 12 at the conveying speed V2.
At this time, the thickness of the film is preferably in the range of 5 to 100 μm, more preferably in the range of 5 to 80 μm, even more preferably in the range of 5 to 40 μm.
A preferable range of the initial tension when winding the film F in the second winding step (S11) is in the range of 20 to 300 N/m.
　（巻取り方法）
　フィルムＦの巻取り方法は、一般に使用されているワインダーを用いればよく、定トルク法、定テンション法、テーパーテンション法、内部応力一定のプログラムテンションコントロール法等の張力をコントロールする方法があり、それらを使い分ければよい。 (Winding method)
The method of winding the film F may use a generally used winder, and there are methods of controlling tension such as a constant torque method, a constant tension method, a taper tension method, and a program tension control method with constant internal stress. should be used properly.
　巻き取る前に、製品となる幅に端部をスリットして裁ち落とし、巻き中の貼りつきや擦り傷防止のために、表面改質処理をフィルム両端に施してもよい。 Before winding, the edges of the film may be slit to the width of the product and cut off, and surface modification treatment may be applied to both ends of the film to prevent sticking and scratches during winding.
３．ポリマー種
　本発明の偏光板保護フィルムの製造方法に用いられるポリマー（樹脂）は、シクロオレフィン系ポリマー（「シクロオレフィン系樹脂」ともいう。）であり、他の熱可塑性ポリマー（樹脂）と比べて延伸性や結晶化度のコントロールがしやすい点や、接着剤が浸透しやすく、偏光フィルムとのより良好な接着性を確保できる点で優れている。
　なお、上記偏光板保護フィルムは、製造後に表面改質処理を施しても良い。 3. Polymer Species The polymer (resin) used in the method for producing the polarizing plate protective film of the present invention is a cycloolefin-based polymer (also referred to as “cycloolefin-based resin”). It is excellent in that it is easy to control the stretchability and crystallinity, that the adhesive easily permeates, and that it can ensure better adhesion to the polarizing film.
The polarizing plate protective film may be subjected to surface modification treatment after production.
　（シクロオレフィン系ポリマー）
　偏光板保護フィルムに含有されるシクロオレフィン系ポリマーは、シクロオレフィン単量体の重合体、又はシクロオレフィン単量体とそれ以外の共重合性単量体との共重合体であることが好ましい。 (Cycloolefin polymer)
The cycloolefin-based polymer contained in the polarizing plate protective film is preferably a polymer of cycloolefin monomers or a copolymer of cycloolefin monomers and other copolymerizable monomers.
　シクロオレフィン単量体としては、ノルボルネン骨格を有するシクロオレフィン単量体であることが好ましく、下記一般式（Ａ－１）又は（Ａ－２）で表される構造を有するシクロオレフィン単量体であることがより好ましい。 The cycloolefin monomer is preferably a cycloolefin monomer having a norbornene skeleton, and a cycloolefin monomer having a structure represented by the following general formula (A-1) or (A-2) It is more preferable to have
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　一般式（Ａ－１）中、Ｒ１～Ｒ４は、各々独立して、水素原子、炭素原子数１～３０の炭化水素基、又は極性基を表す。ｐは、０～２の整数を表す。ただし、Ｒ１～Ｒ４の全てが同時に水素原子を表すことはなく、Ｒ１とＲ２が同時に水素原子を表すことはなく、Ｒ３とＲ４が同時に水素原子を表すことはないものとする。 In general formula (A-1), R 1 to R 4 each independently represent a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a polar group. p represents an integer of 0 to 2; However, R 1 to R 4 do not all represent a hydrogen atom at the same time, R 1 and R 2 do not represent a hydrogen atom at the same time, and R 3 and R 4 do not represent a hydrogen atom at the same time. do.
　一般式（Ａ－１）においてＲ１～Ｒ４で表される炭素原子数１～３０の炭化水素基としては、例えば炭素原子数１～１０の炭化水素基であることが好ましく、炭素原子数１～５の炭化水素基であることがより好ましい。
　炭素原子数１～３０の炭化水素基は、例えばハロゲン原子、酸素原子、窒素原子、硫黄原子又はケイ素原子を含む連結基を更に有していても良い。
　そのような連結基の例には、カルボニル基、イミノ基、エーテル結合、シリルエーテル結合、チオエーテル結合等の２価の極性基が含まれる。
　炭素原子数１～３０の炭化水素基の例には、メチル基、エチル基、プロピル基及びブチル基等が含まれる。 The hydrocarbon group having 1 to 30 carbon atoms represented by R 1 to R 4 in general formula (A-1) is preferably, for example, a hydrocarbon group having 1 to 10 carbon atoms. 1 to 5 hydrocarbon groups are more preferred.
A hydrocarbon group having 1 to 30 carbon atoms may further have a linking group containing, for example, a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom.
Examples of such linking groups include divalent polar groups such as carbonyl groups, imino groups, ether bonds, silyl ether bonds and thioether bonds.
Examples of hydrocarbon groups having 1 to 30 carbon atoms include methyl, ethyl, propyl, butyl and the like.
　一般式（Ａ－１）においてＲ１～Ｒ４で表される極性基の例には、カルボキシ基、ヒドロキシ基、アルコキシ基、アルコキシカルボニル基、アリールオキシカルボニル基、アミノ基、アミド基及びシアノ基が含まれる。
　中でも、カルボキシ基、ヒドロキシ基、アルコキシカルボニル基及びアリールオキシカルボニル基が好ましく、溶液製膜時の溶解性を確保する観点から、アルコキシカルボニル基及びアリールオキシカルボニル基が好ましい。 Examples of polar groups represented by R 1 to R 4 in general formula (A-1) include a carboxy group, a hydroxy group, an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amino group, an amido group and a cyano group. is included.
Among them, a carboxy group, a hydroxy group, an alkoxycarbonyl group and an aryloxycarbonyl group are preferred, and an alkoxycarbonyl group and an aryloxycarbonyl group are preferred from the viewpoint of ensuring solubility during solution film formation.
　一般式（Ａ－１）におけるｐは、偏光板保護フィルムの耐熱性を高める観点から、１又は２であることが好ましい。
　ｐが１又は２であると、得られる重合体がかさ高くなり、ガラス転移温度が向上しやすいためである。 p in formula (A-1) is preferably 1 or 2 from the viewpoint of enhancing the heat resistance of the polarizing plate protective film.
This is because when p is 1 or 2, the resulting polymer becomes bulky and the glass transition temperature tends to be improved.
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
　一般式（Ａ－２）中、Ｒ５は、水素原子、炭素数１～５の炭化水素基、又は炭素数１～５のアルキル基を有するアルキルシリル基を表す。Ｒ６は、カルボキシ基、ヒドロキシ基、アルコキシカルボニル基、アリールオキシカルボニル基、アミノ基、アミド基、シアノ基、又はハロゲン原子（フッ素原子、塩素原子、臭素原子若しくはヨウ素原子）を表す。ｐは、０～２の整数を表す。 In general formula (A-2), R 5 represents a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or an alkylsilyl group having an alkyl group having 1 to 5 carbon atoms. R6 represents a carboxy group, hydroxy group, alkoxycarbonyl group, aryloxycarbonyl group, amino group, amido group, cyano group, or halogen atom (fluorine atom, chlorine atom, bromine atom or iodine atom). p represents an integer of 0 to 2;
　一般式（Ａ－２）におけるＲ５は、炭素数１～５の炭化水素基を表すことが好ましく、炭素数１～３の炭化水素基を表すことがより好ましい。 R 5 in general formula (A-2) preferably represents a hydrocarbon group having 1 to 5 carbon atoms, more preferably a hydrocarbon group having 1 to 3 carbon atoms.
　一般式（Ａ－２）におけるＲ６は、カルボキシ基、ヒドロキシ基、アルコキシカルボニル基及びアリールオキシカルボニル基を表すことが好ましく、溶液製膜時の溶解性を確保する観点から、アルコキシカルボニル基及びアリールオキシカルボニル基がより好ましい。 R 6 in general formula (A-2) preferably represents a carboxy group, a hydroxy group, an alkoxycarbonyl group and an aryloxycarbonyl group. An oxycarbonyl group is more preferred.
　一般式（Ａ－２）におけるｐは、偏光板保護フィルムの耐熱性を高める観点から、１又は２を表すことが好ましい。
　ｐが１又は２を表すと、得られる重合体がかさ高くなり、ガラス転移温度が向上しやすいためである。 p in formula (A-2) preferably represents 1 or 2 from the viewpoint of enhancing the heat resistance of the polarizing plate protective film.
This is because when p is 1 or 2, the resulting polymer becomes bulky and the glass transition temperature tends to be improved.
　一般式（Ａ－２）で表される構造を有するシクロオレフィン単量体は、有機溶媒への溶解性を向上させる点から好ましい。
　一般的に有機化合物は対称性を崩すことによって結晶性が低下するため、有機溶媒への溶解性が向上する。
　一般式（Ａ－２）におけるＲ５及びＲ６は、分子の対称軸に対して片側の環構成炭素原子のみに置換されているので、分子の対称性が低く、すなわち、一般式（Ａ－２）で表される構造を有するシクロオレフィン単量体は溶解性が高いため、偏光板保護フィルムを溶液流延法によって製造する場合に適している。 A cycloolefin monomer having a structure represented by general formula (A-2) is preferable from the viewpoint of improving the solubility in organic solvents.
In general, breaking the symmetry of an organic compound lowers the crystallinity, thereby improving the solubility in an organic solvent.
Since R 5 and R 6 in general formula (A-2) are substituted only on one ring-constituting carbon atom with respect to the symmetry axis of the molecule, the symmetry of the molecule is low, that is, general formula (A- Since the cycloolefin monomer having the structure represented by 2) is highly soluble, it is suitable for producing a polarizing plate protective film by a solution casting method.
　シクロオレフィン単量体の重合体における一般式（Ａ－２）で表される構造を有するシクロオレフィン単量体の含有割合は、シクロオレフィン系ポリマーを構成する全シクロオレフィン単量体の合計に対して、例えば７０モル％以上、好ましくは８０モル％以上、より好ましくは１００モル％とし得る。
　一般式（Ａ－２）で表される構造を有するシクロオレフィン単量体を一定以上含むと、ポリマーの配向性が高まるため、位相差（リターデーション）値が上昇しやすい。 The content of the cycloolefin monomer having the structure represented by the general formula (A-2) in the cycloolefin monomer polymer is based on the total of all cycloolefin monomers constituting the cycloolefin polymer. For example, 70 mol % or more, preferably 80 mol % or more, more preferably 100 mol %.
When the cycloolefin monomer having the structure represented by the general formula (A-2) is contained at a certain level or more, the orientation of the polymer increases, so the retardation value tends to increase.
　以下、一般式（Ａ－１）で表される構造を有するシクロオレフィン単量体の具体例を例示化合物１～１４に示し、一般式（Ａ－２）で表される構造を有するシクロオレフィン単量体の具体例を例示化合物１５～３４に示す。 Hereinafter, specific examples of the cycloolefin monomer having the structure represented by the general formula (A-1) are shown in Exemplary Compounds 1 to 14, and the cycloolefin monomer having the structure represented by the general formula (A-2) Specific examples of the mers are shown in Exemplified Compounds 15-34.
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
　シクロオレフィン単量体と共重合可能な共重合性単量体の例には、シクロオレフィン単量体と開環共重合可能な共重合性単量体、及びシクロオレフィン単量体と付加共重合可能な共重合性単量体等が含まれる。 Examples of copolymerizable monomers copolymerizable with cycloolefin monomers include copolymerizable monomers capable of ring-opening copolymerization with cycloolefin monomers, and addition copolymerization with cycloolefin monomers. possible copolymerizable monomers and the like.
　開環共重合可能な共重合性単量体の例には、シクロブテン、シクロペンテン、シクロヘプテン、シクロオクテン及びジシクロペンタジエン等のシクロオレフィンが含まれる。 Examples of copolymerizable monomers capable of ring-opening copolymerization include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene and dicyclopentadiene.
　付加共重合可能な共重合性単量体の例には、不飽和二重結合含有化合物、ビニル系環状炭化水素単量体及び（メタ）アクリレート等が含まれる。 Examples of addition-copolymerizable copolymerizable monomers include unsaturated double bond-containing compounds, vinyl-based cyclic hydrocarbon monomers, and (meth)acrylates.
　不飽和二重結合含有化合物の例には、炭素原子数２～１２（好ましくは２～８）のオレフィン系化合物が含まれ、その例には、エチレン、プロピレン及びブテン等が含まれる。 Examples of unsaturated double bond-containing compounds include olefinic compounds having 2 to 12 (preferably 2 to 8) carbon atoms, examples of which include ethylene, propylene and butene.
　ビニル系環状炭化水素単量体の例には、４－ビニルシクロペンテン及び２－メチル－４－イソプロペニルシクロペンテン等のビニルシクロペンテン系単量体が含まれる。 Examples of vinyl-based cyclic hydrocarbon monomers include vinylcyclopentene-based monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene.
　（メタ）アクリレートの例には、メチル（メタ）アクリレート、２－エチルヘキシル（メタ）アクリレート及びシクロヘキシル（メタ）アクリレート等の炭素原子数１～２０のアルキル（メタ）アクリレートが含まれる。 Examples of (meth)acrylates include alkyl (meth)acrylates having 1 to 20 carbon atoms such as methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate and cyclohexyl (meth)acrylate.
　シクロオレフィン単量体と共重合性単量体との共重合体におけるシクロオレフィン単量体の含有割合は、共重合体を構成する全単量体の合計に対して、例えば２０～８０モル％の範囲内、好ましくは３０～７０モル％の範囲内とし得る。 The content of the cycloolefin monomer in the copolymer of the cycloolefin monomer and the copolymerizable monomer is, for example, 20 to 80 mol% with respect to the total of all monomers constituting the copolymer. within the range of, preferably within the range of 30 to 70 mol%.
　シクロオレフィン系ポリマーは、前述のとおり、ノルボルネン骨格を有するシクロオレフィン単量体、好ましくは一般式（Ａ－１）又は（Ａ－２）で表される構造を有するシクロオレフィン単量体を重合又は共重合して得られる重合体であり、その例には、以下（１）～（７）の重合体が含まれる。 As described above, the cycloolefin-based polymer is a cycloolefin monomer having a norbornene skeleton, preferably a cycloolefin monomer having a structure represented by general formula (A-1) or (A-2), or Polymers obtained by copolymerization, examples of which include polymers (1) to (7) below.
　（１）シクロオレフィン単量体の開環重合体
　（２）シクロオレフィン単量体と、それと開環共重合可能な共重合性単量体との開環共重合体
　（３）上記（１）又は（２）の開環（共）重合体の水素添加物
　（４）上記（１）又は（２）の開環（共）重合体をフリーデルクラフツ反応により環化した後、水素を添加した（共）重合体
　（５）シクロオレフィン単量体と、不飽和二重結合含有化合物との飽和共重合体
　（６）シクロオレフィン単量体のビニル系環状炭化水素単量体との付加共重合体及びその水素添加物
　（７）シクロオレフィン単量体と、（メタ）アクリレートとの交互共重合体 (1) A ring-opening polymer of a cycloolefin monomer (2) A ring-opening copolymer of a cycloolefin monomer and a copolymerizable monomer capable of ring-opening copolymerization thereof (3) Above (1) or a hydrogenated product of the ring-opening (co)polymer of (2) (4) the ring-opening (co)polymer of (1) or (2) above is cyclized by the Friedel-Crafts reaction and then hydrogen is added (Co)polymer (5) Saturated copolymer of a cycloolefin monomer and an unsaturated double bond-containing compound (6) Addition copolymerization of a cycloolefin monomer with a vinyl-based cyclic hydrocarbon monomer Coalescence and its hydrogenation product (7) Alternating copolymer of cycloolefin monomer and (meth)acrylate
　上記（１）～（７）の重合体は、いずれも公知の方法、例えば特開２００８－１０７５３４号公報や特開２００５－２２７６０６号公報に記載の方法で得ることができる。 The above polymers (1) to (7) can all be obtained by known methods, for example, the methods described in JP-A-2008-107534 and JP-A-2005-227606.
　例えば上記（２）の開環共重合に用いられる触媒や溶媒は、例えば特開２００８－１０７５３４号公報の段落００１９～００２４に記載のものを使用できる。
　上記（３）及び（６）の水素添加物に用いられる触媒は、例えば特開２００８－１０７５３４号公報の段落００２５～００２８に記載のものを使用できる。
　上記（４）のフリーデルクラフツ反応に用いられる酸性化合物は、例えば特開２００８－１０７５３４号公報の段落００２９に記載のものを使用できる。
　上記（５）～（７）の付加重合に用いられる触媒は、例えば特開２００５－２２７６０６号公報の段落００５８～００６３に記載のものを使用できる。
　上記（７）の交互共重合反応は、例えば特開２００５－２２７６０６号公報の段落００７１及び００７２に記載の方法で行うことができる。 For example, the catalyst and solvent used in the ring-opening copolymerization of (2) above can be those described in paragraphs 0019 to 0024 of JP-A-2008-107534.
As the catalyst used for the hydrogenated products of (3) and (6) above, for example, those described in paragraphs 0025 to 0028 of JP-A-2008-107534 can be used.
As the acidic compound used in the Friedel-Crafts reaction of (4) above, for example, those described in paragraph 0029 of JP-A-2008-107534 can be used.
As the catalyst used in the addition polymerization of (5) to (7) above, for example, those described in paragraphs 0058 to 0063 of JP-A-2005-227606 can be used.
The alternating copolymerization reaction (7) above can be carried out, for example, by the method described in paragraphs 0071 and 0072 of JP-A-2005-227606.
　中でも、上記（１）～（３）及び（５）の重合体が好ましく、上記（３）及び（５）の重合体がより好ましい。 Among them, the polymers (1) to (3) and (5) above are preferred, and the polymers (3) and (5) above are more preferred.
　すなわち、シクロオレフィン系ポリマーは、得られるシクロオレフィン系ポリマーのガラス転移温度を高くし、かつ光透過率を高くすることができる点で、下記一般式（Ｂ－１）で表される構造単位と下記一般式（Ｂ－２）で表される構造単位の少なくとも一方を含むことが好ましく、一般式（Ｂ－２）で表される構造単位のみを含むか、又は一般式（Ｂ－１）で表される構造単位と一般式（Ｂ－２）で表される構造単位の両方を含むことがより好ましい。 That is, the cycloolefin-based polymer can increase the glass transition temperature of the obtained cycloolefin-based polymer and increase the light transmittance. It preferably contains at least one of the structural units represented by the following general formula (B-2), and contains only the structural unit represented by the general formula (B-2), or the general formula (B-1) It is more preferable to include both the structural unit represented by formula (B-2) and the structural unit represented by general formula (B-2).
　一般式（Ｂ－１）で表される構造単位は、前述の一般式（Ａ－１）で表されるシクロオレフィン単量体由来の構造単位であり、一般式（Ｂ－２）で表される構造単位は、前述の一般式（Ａ－２）で表されるシクロオレフィン単量体由来の構造単位である。 The structural unit represented by general formula (B-1) is a structural unit derived from the cycloolefin monomer represented by general formula (A-1) described above, and is represented by general formula (B-2). is a structural unit derived from the cycloolefin monomer represented by the general formula (A-2) described above.
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　一般式（Ｂ－１）中、Ｘは、－ＣＨ＝ＣＨ－又は－ＣＨ２ＣＨ２－を表す。Ｒ１～Ｒ４及びｐは、それぞれ一般式（Ａ－１）のＲ１～Ｒ４及びｐと同義である。 In general formula (B-1), X represents -CH=CH- or -CH 2 CH 2 -. R 1 to R 4 and p have the same definitions as R 1 to R 4 and p in general formula (A-1), respectively.
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
　一般式（Ｂ－２）中、Ｘは、－ＣＨ＝ＣＨ－又は－ＣＨ２ＣＨ２－を表す。Ｒ５～Ｒ６及びｐは、それぞれ一般式（Ａ－２）のＲ５～Ｒ６及びｐと同義である。 In general formula (B-2), X represents -CH=CH- or -CH 2 CH 2 -. R 5 to R 6 and p have the same definitions as R 5 to R 6 and p in general formula (A-2), respectively.
　本発明に係るシクロオレフィン系ポリマーは、市販品であっても良い。
　シクロオレフィン系ポリマーの市販品の例には、ＪＳＲ（株）製のアートン（Ａｒｔｏｎ）Ｇ（例えばＧ７８１０等）、アートンＦ、アートンＲ（例えばＲ４５００、Ｒ４９００及びＲ５０００等）、及びアートンＲＸが含まれる。 The cycloolefin-based polymer according to the present invention may be a commercial product.
Commercially available examples of cycloolefin-based polymers include JSR Corporation's Arton G (e.g. G7810), Arton F, Arton R (e.g. R4500, R4900 and R5000), and Arton RX. .
　シクロオレフィン系ポリマーの固有粘度〔η〕ｉｎｈは、３０℃の測定において、０．２～５ｃｍ３／ｇの範囲内であることが好ましく、０．３～３ｃｍ３／ｇの範囲内であることがより好ましく、０．４～１．５ｃｍ３／ｇの範囲内であることが更に好ましい。 The intrinsic viscosity [η]inh of the cycloolefin polymer is preferably in the range of 0.2 to 5 cm 3 /g, more preferably in the range of 0.3 to 3 cm 3 /g, when measured at 30°C. is more preferable, and more preferably within the range of 0.4 to 1.5 cm 3 /g.
　シクロオレフィン系ポリマーの数平均分子量（Ｍｎ）は、８０００～１０００００の範囲内であることが好ましく、１００００～８００００の範囲内であることがより好ましく、１２０００～５００００の範囲内であることが更に好ましい。 The number average molecular weight (Mn) of the cycloolefin polymer is preferably within the range of 8000 to 100000, more preferably within the range of 10000 to 80000, and even more preferably within the range of 12000 to 50000. .
　シクロオレフィン系ポリマーの重量平均分子量（Ｍｗ）は、２００００～３０００００の範囲内であることが好ましく、３００００～２５００００の範囲内であることがより好ましく、４００００～２０００００の範囲内であることが更に好ましい。 The weight average molecular weight (Mw) of the cycloolefin polymer is preferably within the range of 20000 to 300000, more preferably within the range of 30000 to 250000, and even more preferably within the range of 40000 to 200000. .
　シクロオレフィン系ポリマーの数平均分子量や重量平均分子量は、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）にてポリスチレン換算にて測定することができる。 The number average molecular weight and weight average molecular weight of the cycloolefin polymer can be measured by gel permeation chromatography (GPC) in terms of polystyrene.
　（ゲルパーミエーションクロマトグラフィー）
　溶媒：　　　メチレンクロライド
　カラム：　　Ｓｈｏｄｅｘ　Ｋ８０６、Ｋ８０５、Ｋ８０３Ｇ（昭和電工（株）製を３本接続して使用した）
　カラム温度：２５℃
　試料濃度：　０．１質量％
　検出器：　　ＲＩ　Ｍｏｄｅｌ　５０４（ＧＬサイエンス社製）
　ポンプ：　　Ｌ６０００（日立製作所（株）製）
　流量：　　　１．０ｍｌ／ｍｉｎ
　校正曲線：　標準ポリスチレンＳＴＫ　ｓｔａｎｄａｒｄ　ポリスチレン（東ソー（株）製）Ｍｗ＝５００～２８０００００の範囲内の１３サンプルによる校正曲線を使用した。１３サンプルは、ほぼ等間隔に用いることが好ましい。 (Gel permeation chromatography)
Solvent: methylene chloride Column: Shodex K806, K805, K803G (3 columns manufactured by Showa Denko Co., Ltd. were connected and used)
Column temperature: 25°C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Science)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0ml/min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) A calibration curve with 13 samples within the range of Mw = 500 to 2800000 was used. The 13 samples are preferably used at approximately equal intervals.
　固有粘度〔η〕ｉｎｈ、数平均分子量及び重量平均分子量が上記範囲にあると、シクロオレフィン系ポリマーの耐熱性、耐水性、耐薬品性、機械的特性、及びフィルムとしての成形加工性が良好となる。 When the intrinsic viscosity [η] inh, the number average molecular weight and the weight average molecular weight are within the above ranges, the heat resistance, water resistance, chemical resistance, mechanical properties, and moldability as a film of the cycloolefin polymer are good. Become.
　シクロオレフィン系ポリマーのガラス転移温度（Ｔｇ）は、通常、１１０℃以上であり、１１０～３５０℃の範囲内であることが好ましく、１２０～２５０℃の範囲内であることがより好ましく、１２０～２２０℃の範囲内であることが更に好ましい。 The glass transition temperature (Tg) of the cycloolefin polymer is usually 110° C. or higher, preferably in the range of 110 to 350° C., more preferably in the range of 120 to 250° C., and 120 to It is more preferably within the range of 220°C.
　ガラス転移温度（Ｔｇ）が１１０℃以上であると、高温条件下での変形を抑制しやすい。
　一方、ガラス転移温度（Ｔｇ）が３５０℃以下であると、成形加工が容易となり、成形加工時の熱によるポリマー（樹脂）の劣化も抑制しやすい。 When the glass transition temperature (Tg) is 110°C or higher, it is easy to suppress deformation under high temperature conditions.
On the other hand, when the glass transition temperature (Tg) is 350° C. or less, the molding process becomes easy, and deterioration of the polymer (resin) due to heat during the molding process can be easily suppressed.
　シクロオレフィン系ポリマーの含有量は、フィルムに対して７０質量％以上であることが好ましく、８０質量％以上であることがより好ましい。 The content of the cycloolefin polymer is preferably 70% by mass or more, more preferably 80% by mass or more, relative to the film.
４．偏光板
　本発明に係る偏光板は、偏光子層と、本発明の偏光板保護フィルムと、それらの間に配置された、水系接着剤又は紫外線硬化型接着剤を含有する接着層とを有する。 4. Polarizing Plate The polarizing plate according to the present invention has a polarizer layer, the polarizing plate protective film of the present invention, and an adhesive layer containing a water-based adhesive or an ultraviolet curable adhesive disposed therebetween.
　（４．１）偏光子層
　本発明に係る偏光子層は、少なくとも偏光フィルム（「偏光子フィルム」又は「偏光子膜」ともいう。）からなる層である。
　ここで、「偏光子」とは、一定方向の偏波面の光だけを通す素子をいう。
　本発明に係る偏光フィルムは、ポリビニルアルコール系偏光フィルムである。
　ポリビニルアルコール系偏光フィルムには、ポリビニルアルコール系フィルムにヨウ素を染色させたものと、二色性染料を染色させたものとがある。 (4.1) Polarizer Layer The polarizer layer according to the present invention is a layer composed of at least a polarizing film (also referred to as "polarizer film" or "polarizer film").
Here, the term "polarizer" refers to an element that transmits only light with a plane of polarization in a certain direction.
The polarizing film according to the present invention is a polyvinyl alcohol-based polarizing film.
The polyvinyl alcohol-based polarizing film includes a polyvinyl alcohol-based film dyed with iodine and a polyvinyl alcohol-based film dyed with a dichroic dye.
　ポリビニルアルコール系偏光フィルムは、ポリビニルアルコール系フィルムを一軸延伸した後、ヨウ素又は二色性染料で染色したフィルム（好ましくはさらにホウ素化合物で耐久性処理を施したフィルム）であってもよいし；ポリビニルアルコール系フィルムをヨウ素又は二色性染料で染色した後、一軸延伸したフィルム（好ましくは、さらにホウ素化合物で耐久性処理を施したフィルム）であってもよい。
　偏光子層の吸収軸は、通常、最大延伸方向と平行である。 The polyvinyl alcohol-based polarizing film may be a film obtained by uniaxially stretching a polyvinyl alcohol-based film and then dyeing it with iodine or a dichroic dye (preferably a film further subjected to durability treatment with a boron compound); A film obtained by dyeing an alcohol-based film with iodine or a dichroic dye and then uniaxially stretching the film (preferably, a film further subjected to a durability treatment with a boron compound) may be used.
The absorption axis of the polarizer layer is generally parallel to the direction of maximum stretch.
　例えば、特開２００３－２４８１２３号公報、特開２００３－３４２３２２号公報等に記載のエチレン単位の含有量１～４モル％、重合度２０００～４０００、けん化度９９．０～９９．９９モル％のエチレン変性ポリビニルアルコールが用いられる。 For example, JP 2003-248123, JP 2003-342322, etc. ethylene unit content 1 to 4 mol%, degree of polymerization 2000 to 4000, degree of saponification 99.0 to 99.99 mol% Ethylene modified polyvinyl alcohol is used.
　偏光子層の厚さは、５～３０μｍであることが好ましく、偏光板を薄型化するため等から、５～２０μｍであることがより好ましい。 The thickness of the polarizer layer is preferably 5 to 30 μm, and more preferably 5 to 20 μm in order to thin the polarizing plate.
　（４．２）偏光板保護フィルム
　本発明の偏光板保護フィルムの製造方法により製造される偏光板保護フィルムは、偏光子層の少なくとも一方の面（少なくとも液晶セルと対向する面）に配置されている。
　偏光板保護フィルムの偏光子層が積層される面は、後述の活性化処理が施されている。 (4.2) Polarizing Plate Protective Film The polarizing plate protective film produced by the method for producing a polarizing plate protective film of the present invention is disposed on at least one surface (at least the surface facing the liquid crystal cell) of the polarizer layer. there is
The surface of the polarizing plate protective film on which the polarizer layer is to be laminated is subjected to activation treatment, which will be described later.
　本発明の偏光板保護フィルムの製造方法により製造される偏光板保護フィルムが偏光子層の一方の面のみに配置されている場合、偏光子層の他方の面には、位相差フィルム等の光学フィルムが配置されうる。
　他の光学フィルムの例には、市販のセルロースエステルフィルム（例えば、コニカミノルタタックＫＣ８ＵＸ、ＫＣ５ＵＸ、ＫＣ４ＵＸ、ＫＣ８ＵＣＲ３、ＫＣ４ＳＲ、ＫＣ４ＢＲ、ＫＣ４ＣＲ、ＫＣ４ＤＲ、ＫＣ４ＦＲ、ＫＣ４ＫＲ、ＫＣ８ＵＹ、ＫＣ６ＵＹ、ＫＣ４ＵＹ、ＫＣ４ＵＥ、ＫＣ８ＵＥ、ＫＣ８ＵＹ－ＨＡ、ＫＣ２ＵＡ、ＫＣ４ＵＡ、ＫＣ６ＵＡ、ＫＣ８ＵＡ、ＫＣ２ＵＡＨ、ＫＣ４ＵＡＨ、ＫＣ６ＵＡＨ、以上コニカミノルタ（株）製、フジタックＴ４０ＵＺ、フジタックＴ６０ＵＺ、フジタックＴ８０ＵＺ、フジタックＴＤ８０ＵＬ、フジタックＴＤ６０ＵＬ、フジタックＴＤ４０ＵＬ、フジタックＲ０２、フジタックＲ０６、以上富士フィルム（株）製）などが含まれる。 When the polarizing plate protective film produced by the method for producing a polarizing plate protective film of the present invention is disposed only on one surface of the polarizer layer, the other surface of the polarizer layer is coated with an optical film such as a retardation film. A film can be placed.
Examples of other optical films include commercially available cellulose ester films (e.g., Konica Minolta Tac KC8UX, KC5UX, KC4UX, KC8UCR3, KC4SR, KC4BR, KC4CR, KC4DR, KC4FR, KC4KR, KC8UY, KC6UY, KC4UY, KC4UE, KC8UE, KC8UY-HA, KC2UA, KC4UA, KC6UA, KC8UA, KC2UAH, KC4UAH, KC6UAH, manufactured by Konica Minolta, Fujitac T40UZ, Fujitac T60UZ, Fujitac T80UZ, Fujitac TD80UL, Fujitac TD60UL, Fujitac TD60UL, Fujitac R0RL, TD40 (manufactured by Fuji Film Co., Ltd.).
　他の光学フィルムの厚さは、例えば５～１００μｍ、好ましくは４０～８０μｍでありうる。 The thickness of other optical films can be, for example, 5-100 μm, preferably 40-80 μm.
　（４．３）接着層
　接着層は、光学フィルム（又は他の光学フィルム）と偏光子層との間に配置された、後述の水系接着剤又は紫外線硬化型接着剤を乾燥させたものである。 (4.3) Adhesive Layer The adhesive layer is formed by drying a water-based adhesive or an ultraviolet curable adhesive described below, which is placed between the optical film (or other optical film) and the polarizer layer. .
　接着層の厚さは、例えば０．０１～１０μｍ、好ましくは０．０３～５μｍ程度でありうる。 The thickness of the adhesive layer can be, for example, 0.01 to 10 μm, preferably about 0.03 to 5 μm.
　（４．４）偏光板の製造方法
　本発明に係る偏光板の製造方法は、１）偏光板保護フィルムの表面に、活性化処理を施す工程と、２）偏光板保護フィルムの活性化処理が施された表面に、水系接着剤又は紫外線硬化型接着剤を介して偏光子層（偏光フィルム）を積層する工程と、３）得られた積層物を乾燥させる工程と有する。 (4.4) Method for producing a polarizing plate The method for producing a polarizing plate according to the present invention comprises: 1) a step of applying an activation treatment to the surface of the polarizing plate protective film; and 2) an activation treatment of the polarizing plate protective film. It has a step of laminating a polarizer layer (polarizing film) on the applied surface via a water-based adhesive or an ultraviolet curable adhesive, and 3) drying the obtained laminate.
　１）の工程について
　偏光板保護フィルムの表面（偏光子層と貼り合わせる面）に活性化処理を施す。
　それにより、偏光子層との接着性を得られやすくする。
　具体的には、活性化処理により、偏光板保護フィルムに含まれる特定のグラフト重合体の側鎖のシロキサン結合やエーテル結合、３級炭素原子などを親水化させて、水系接着剤との親和性を高めたり、相互作用させやすくしたりすることで、偏光板保護フィルムと偏光子層とを接着させやすくする。 Regarding Step 1) The surface of the polarizing plate protective film (the surface to be bonded to the polarizer layer) is subjected to an activation treatment.
This makes it easier to obtain adhesiveness with the polarizer layer.
Specifically, the siloxane bond, ether bond, tertiary carbon atom, etc. of the side chain of the specific graft polymer contained in the polarizing plate protective film are made hydrophilic by the activation treatment, thereby improving the affinity with the water-based adhesive. By increasing or facilitating interaction, the polarizing plate protective film and the polarizer layer are easily adhered.
　活性化処理の例には、コロナ処理、プラズマ処理及び鹸化処理が含まれ、好ましくはコロナ処理及びプラズマ処理であり、より好ましくはコロナ処理である。 Examples of activation treatments include corona treatment, plasma treatment and saponification treatment, preferably corona treatment and plasma treatment, more preferably corona treatment.
　活性化処理条件は、特定のグラフト重合体の側鎖に含まれるシロキサン結合やエーテル結合、３級炭素原子などを十分に活性化させうる程度であればよい。
　活性化処理がコロナ処理である場合、照射量は、１００～１０００（Ｗ・ｍｉｎ／ｍ２）であることが好ましく、１５０～９００（Ｗ・ｍｉｎ／ｍ２）であることがより好ましい。 The conditions for the activation treatment should be such that the siloxane bonds, ether bonds, tertiary carbon atoms, etc. contained in the side chains of the specific graft polymer can be sufficiently activated.
When the activation treatment is corona treatment, the irradiation dose is preferably 100 to 1000 (W·min/m 2 ), more preferably 150 to 900 (W·min/m 2 ).
　２）の工程について
　次いで、光学フィルムの活性化処理が施された面に、水系接着剤又は紫外線硬化型接着剤を介して偏光子層を積層する。 Regarding Step 2) Next, a polarizer layer is laminated on the activated surface of the optical film via a water-based adhesive or an ultraviolet curable adhesive.
　（水系接着剤）
　水系接着剤の例には、ビニル系、ゼラチン系、ビニル系ラテックス系、ポリウレタン系、イソシアネート系、ポリエステル系、エポキシ系などが含まれる。
　中でも、偏光子層であるポリビニルアルコール系偏光フィルムとの接着性が得られやすい観点などから、ビニル系ポリマーを含む水系接着剤が好ましく、ポリビニルアルコール系ポリマーを含む水接着剤（完全ケン化型ポリビニルアルコール水溶液など）がより好ましい。
　ポリビニルアルコール系ポリマーを含む水系接着剤は、ホウ酸やホウ砂、グルタルアルデヒドやメラミン、シュウ酸などの水溶性架橋剤をさらに含んでもよい。 (water-based adhesive)
Examples of water-based adhesives include vinyl-based, gelatin-based, vinyl-based latex-based, polyurethane-based, isocyanate-based, polyester-based, and epoxy-based adhesives.
Among them, a water-based adhesive containing a vinyl-based polymer is preferable from the viewpoint of easily obtaining adhesion to the polyvinyl alcohol-based polarizing film that is the polarizer layer. alcohol aqueous solution, etc.) is more preferred.
A water-based adhesive containing a polyvinyl alcohol-based polymer may further contain a water-soluble cross-linking agent such as boric acid, borax, glutaraldehyde, melamine, or oxalic acid.
　（紫外線硬化型接着剤）
　紫外線硬化型接着剤は、光ラジカル重合性組成物であってもよいし、光カチオン重合性組成物であってもよい。
　中でも、光カチオン重合性組成物が好ましい。 (UV curable adhesive)
The ultraviolet curable adhesive may be a radically photopolymerizable composition or a cationic photopolymerizable composition.
Among them, a photo-cationically polymerizable composition is preferred.
　光カチオン重合性組成物は、エポキシ系化合物と、光カチオン重合開始剤とを含む。 The photocationically polymerizable composition contains an epoxy compound and a photocationic polymerization initiator.
　エポキシ系化合物とは、分子内に１以上、好ましくは２以上のエポキシ基を有する化合物である。
　エポキシ系化合物の例には、脂環式ポリオールに、エピクロロヒドリンを反応させて得られる水素化エポキシ系化合物（脂環式環を有するポリオールのグリシジルエーテル）；脂肪族多価アルコール又はそのアルキレンオキサイド付加物のポリグリシジルエーテルなどの脂肪族エポキシ系化合物；脂環式環に結合したエポキシ基を分子内に１以上有する脂環式エポキシ系化合物が含まれる。
　エポキシ系化合物は、一種のみを使用してもよいし、二種以上を併用してもよい。 An epoxy-based compound is a compound having one or more, preferably two or more epoxy groups in the molecule.
Examples of epoxy compounds include hydrogenated epoxy compounds obtained by reacting epichlorohydrin with alicyclic polyols (glycidyl ethers of polyols having alicyclic rings); aliphatic polyhydric alcohols or their alkylene Aliphatic epoxy compounds such as polyglycidyl ethers of oxide adducts; and alicyclic epoxy compounds having one or more epoxy groups bonded to an alicyclic ring in the molecule.
Epoxy compounds may be used alone or in combination of two or more.
　光カチオン重合開始剤は、例えば芳香族ジアゾニウム塩；芳香族ヨードニウム塩や芳香族スルホニウム塩などのオニウム塩；鉄－アレーン錯体などでありうる。 The photocationic polymerization initiator can be, for example, an aromatic diazonium salt; an onium salt such as an aromatic iodonium salt or an aromatic sulfonium salt; an iron-arene complex.
　光カチオン重合開始剤は、必要に応じてオキセタン、ポリオールなどのカチオン重合促進剤、光増感剤、溶剤などの添加剤をさらに含んでもよい。 The photocationic polymerization initiator may further contain additives such as cationic polymerization accelerators such as oxetane and polyol, photosensitizers, and solvents, if necessary.
　接着剤層の厚さは、特に限定されないが、例えば０．０１～１０μｍであり、好ましくは０．０１～５μｍ程度でありうる。 Although the thickness of the adhesive layer is not particularly limited, it can be, for example, 0.01 to 10 μm, preferably about 0.01 to 5 μm.
　３）の工程について
　次いで、得られた積層物を乾燥させて、偏光板を得る。 Regarding Step 3) Next, the obtained laminate is dried to obtain a polarizing plate.
　乾燥は、加熱乾燥によって行うことができる。
　乾燥温度は、水系接着剤又は紫外線硬化型接着剤が十分に乾燥する温度であればよく、例えば６０～１００℃としうる。 Drying can be performed by heat drying.
The drying temperature may be any temperature that sufficiently dries the water-based adhesive or the UV-curable adhesive, and may be, for example, 60 to 100.degree.
５．その他の添加剤
　本発明の偏光板保護フィルムの製造方法には、その他の添加剤として上記シクロオレフィン系ポリマー（ＣＯＰ）の他に以下のものを含有していてもよい。 5. Other Additives In the method for producing a polarizing plate protective film of the present invention, the following additives may be contained in addition to the above cycloolefin polymer (COP) as other additives.
　（５．１）可塑剤
　偏光板保護フィルムは、例えば偏光板保護フィルム等に加工性を付与する目的で少なくとも一種の可塑剤を含むことが好ましい。
　可塑剤は単独で又は二種以上混合して用いることが好ましい。 (5.1) Plasticizer The polarizing plate protective film preferably contains at least one kind of plasticizer for the purpose of imparting workability to the polarizing plate protective film, for example.
The plasticizers are preferably used singly or in combination of two or more.
　可塑剤の中でも、糖エステル、ポリエステル、及びスチレン系化合物からなる群から選択される少なくとも一種の可塑剤を含むことが、透湿性の効果的な制御及びセルロースエステル等の基材ポリマー（樹脂）との相溶性を高度に両立できる観点から好ましい。 Among the plasticizers, the inclusion of at least one plasticizer selected from the group consisting of sugar esters, polyesters, and styrenic compounds is effective in controlling moisture permeability and forming base polymers (resins) such as cellulose esters. It is preferable from the viewpoint of being able to achieve a high degree of compatibility.
　当該可塑剤は、分子量が１５０００以下、さらには１００００以下であることが、耐湿熱性の改善とセルロースエステル等の基材ポリマー（樹脂）との相溶性を両立する観点から好ましい。 The plasticizer preferably has a molecular weight of 15,000 or less, more preferably 10,000 or less, from the viewpoint of achieving both improvement in wet heat resistance and compatibility with the base polymer (resin) such as cellulose ester.
　当該分子量が１００００以下である化合物が重合体である場合は、重量平均分子量（Ｍｗ）が１００００以下であることが好ましい。
　好ましい重量平均分子量（Ｍｗ）の範囲は１００～１００００の範囲内であり、更に好ましくは、４００～８０００の範囲内である。 When the compound having a molecular weight of 10,000 or less is a polymer, the weight average molecular weight (Mw) is preferably 10,000 or less.
A preferred weight average molecular weight (Mw) range is 100 to 10,000, more preferably 400 to 8,000.
　特に本発明の効果を得るためには、当該分子量が１５００以下の化合物を、基材ポリマー（樹脂）１００質量部に対して６～４０質量部の範囲内で含有することが好ましく、１０～２０質量部の範囲内で含有させることがより好ましい。
　上記範囲内で含有させることにより、透湿性の効果的な制御と基材樹脂との相溶性を両立することができ、好ましい。 In particular, in order to obtain the effect of the present invention, the compound having a molecular weight of 1500 or less is preferably contained within the range of 6 to 40 parts by mass with respect to 100 parts by mass of the base polymer (resin), and 10 to 20 parts by mass. It is more preferable to contain within the range of parts by mass.
By containing it within the above range, it is possible to achieve both effective control of moisture permeability and compatibility with the base resin, which is preferable.
　（糖エステル）
　偏光板保護フィルムには、加水分解防止を目的として、糖エステル化合物を含有させてもよい。
　具体的には、糖エステル化合物として、ピラノース構造又はフラノース構造の少なくとも一種を１個以上１２個以下有し、その構造のＯＨ基の全て若しくは一部をエステル化した糖エステルを使用することができる。 (sugar ester)
The polarizing plate protective film may contain a sugar ester compound for the purpose of preventing hydrolysis.
Specifically, as the sugar ester compound, a sugar ester having at least 1 to 12 pyranose structures or at least one furanose structure and having all or part of the OH groups in that structure esterified can be used. .
　（ポリエステル）
　偏光板保護フィルムには、ポリエステルを含有させることもできる。 (polyester)
The polarizing plate protective film can also contain polyester.
　ポリエステルは特に限定されないが、例えばジカルボン酸、又はこれらのエステル形成性誘導体とグリコールとの縮合反応により得ることができる末端がヒドロキシ基となる重合体（ポリエステルポリオール）、又は当該ポリエステルポリオールの末端のヒドロキシ基がモノカルボン酸で封止された重合体（末端封止ポリエステル）を用いることができる。
　ここでいうエステル形成性誘導体とは、ジカルボン酸のエステル化物、ジカルボン酸クロライド、ジカルボン酸の無水物のことである。 The polyester is not particularly limited, but for example, a polymer (polyester polyol) having a terminal hydroxy group obtained by a condensation reaction between a dicarboxylic acid or an ester-forming derivative thereof and a glycol, or a terminal hydroxy group of the polyester polyol. A polymer whose groups are blocked with monocarboxylic acid (terminal-blocked polyester) can be used.
The term "ester-forming derivative" as used herein means an esterified product of dicarboxylic acid, a dicarboxylic acid chloride, and an anhydride of dicarboxylic acid.
　（スチレン系化合物）
　偏光板保護フィルムには、上記糖エステル、ポリエステルに加えて又はこれに代えて、偏光板保護フィルムの耐水性改善を目的として、スチレン系化合物を用いることもできる。 (styrene compound)
For the polarizing plate protective film, a styrene compound may be used in addition to or instead of the above sugar esters and polyesters for the purpose of improving the water resistance of the polarizing plate protective film.
　スチレン系化合物は、スチレン系モノマーの単独重合体であってもよいし、スチレン系モノマーとそれ以外の共重合モノマーとの共重合体であってもよい。
　スチレン系化合物におけるスチレン系モノマー由来の構成単位の含有割合は、分子構造が一定以上の嵩高さを有するためには、好ましくは３０～１００モル％の範囲内、より好ましくは５０～１００モル％の範囲内でありうる。 The styrene-based compound may be a homopolymer of a styrene-based monomer, or a copolymer of a styrene-based monomer and another copolymerizable monomer.
The content of structural units derived from styrene-based monomers in the styrene-based compound is preferably in the range of 30 to 100 mol%, more preferably 50 to 100 mol%, in order for the molecular structure to have a certain or higher bulkiness. can be in range.
　スチレン系モノマーの例には、スチレン；α－メチルスチレン、β－メチルスチレン、ｐ－メチルスチレン等のアルキル置換スチレン類；４－クロロスチレン、４－ブロモスチレン等のハロゲン置換スチレン類；ｐ－ヒドロキシスチレン、α－メチル－ｐ－ヒドロキシスチレン、２－メチル－４－ヒドロキシスチレン、３，４－ジヒドロキシスチレン等のヒドロキシスチレン類；ビニルベンジルアルコール類；ｐ－メトキシスチレン、ｐ－ｔｅｒｔ－ブトキシスチレン、ｍ－ｔｅｒｔ－ブトキシスチレン等のアルコキシ置換スチレン類；３－ビニル安息香酸、４－ビニル安息香酸等のビニル安息香酸類；４－ビニルベンジルアセテート；４－アセトキシスチレン；２－ブチルアミドスチレン、４－メチルアミドスチレン、ｐ－スルホンアミドスチレン等のアミドスチレン類；３－アミノスチレン、４－アミノスチレン、２－イソプロペニルアニリン、ビニルベンジルジメチルアミン等のアミノスチレン類；３－ニトロスチレン、４－ニトロスチレン等のニトロスチレン類；３－シアノスチレン、４－シアノスチレン等のシアノスチレン類；ビニルフェニルアセトニトリル；フェニルスチレン等のアリールスチレン類、インデン類等が含まれる。
　スチレン系モノマーは、一種類であっても、二種以上を組み合わせてもよい。 Examples of styrenic monomers include styrene; alkyl-substituted styrenes such as α-methylstyrene, β-methylstyrene and p-methylstyrene; halogen-substituted styrenes such as 4-chlorostyrene and 4-bromostyrene; hydroxystyrenes such as styrene, α-methyl-p-hydroxystyrene, 2-methyl-4-hydroxystyrene, 3,4-dihydroxystyrene; vinylbenzyl alcohols; p-methoxystyrene, p-tert-butoxystyrene, m Alkoxy-substituted styrenes such as -tert-butoxystyrene; vinyl benzoic acids such as 3-vinylbenzoic acid and 4-vinylbenzoic acid; 4-vinylbenzyl acetate; 4-acetoxystyrene; 2-butylamidostyrene, 4-methylamide amidostyrenes such as styrene and p-sulfonamidostyrene; aminostyrenes such as 3-aminostyrene, 4-aminostyrene, 2-isopropenylaniline and vinylbenzyldimethylamine; 3-nitrostyrene and 4-nitrostyrene Nitrostyrenes; cyanostyrenes such as 3-cyanostyrene and 4-cyanostyrene; vinylphenylacetonitrile; arylstyrenes such as phenylstyrene;
The styrenic monomer may be of one type or a combination of two or more types.
　（５．２）任意成分
　偏光板保護フィルムは、酸化防止剤、着色剤、紫外線吸収剤、マット剤、アクリル粒子、水素結合性溶媒及びイオン性界面活性剤等の他の任意成分を含みうる。
　これらの成分は、基材ポリマー（樹脂）１００質量部に対して０．０１～２０質量部の範囲内で添加することができる。 (5.2) Optional Components The polarizing plate protective film may contain other optional components such as antioxidants, colorants, UV absorbers, matting agents, acrylic particles, hydrogen-bonding solvents and ionic surfactants.
These components can be added within the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of the base polymer (resin).
　（酸化防止剤）
　偏光板保護フィルムは、酸化防止剤としては、通常知られているものを使用することができる。
　特に、ラクトン系、イオウ系、フェノール系、二重結合系、ヒンダードアミン系、リン系の各化合物を好ましく用いることができる。 (Antioxidant)
The polarizing plate protective film can use commonly known antioxidants.
In particular, lactone, sulfur, phenol, double bond, hindered amine, and phosphorus compounds can be preferably used.
　これらの酸化防止剤等は、偏光板保護フィルムの主原料であるポリマー（樹脂）に対して０．０５～２０質量％の範囲内、好ましくは０．１～１質量％の範囲内で添加される。
　これらの酸化防止剤等は、一種のみを用いるよりも数種の異なった系の化合物を併用することで相乗効果を得ることができる。
　例えばラクトン系、リン系、フェノール系及び二重結合系化合物の併用は好ましい。 These antioxidants and the like are added within the range of 0.05 to 20% by mass, preferably within the range of 0.1 to 1% by mass, relative to the polymer (resin) that is the main raw material of the polarizing plate protective film. be.
A synergistic effect can be obtained by using several different types of compounds in combination rather than using only one of these antioxidants.
For example, combined use of lactone, phosphorus, phenol and double bond compounds is preferred.
　（着色剤）
　偏光板保護フィルムは、本発明の効果を損なわない範囲内で、色味調整のために、着色剤を含むことが好ましい。 (coloring agent)
The polarizing plate protective film preferably contains a coloring agent for color adjustment within a range that does not impair the effects of the present invention.
　着色剤というのは染料や顔料を意味し、本発明では、液晶画面の色調を青色調にする効果又はイエローインデックスの調整、ヘイズの低減を有するものを指す。 A coloring agent means a dye or a pigment, and in the present invention, refers to a substance that has the effect of making the color tone of the liquid crystal screen bluish, adjusting the yellow index, or reducing haze.
　着色剤としては各種の染料、顔料が使用可能だが、アントラキノン染料、アゾ染料、フタロシアニン顔料等が有効である。 Various dyes and pigments can be used as coloring agents, but anthraquinone dyes, azo dyes, phthalocyanine pigments, etc. are effective.
　（紫外線吸収剤）
　偏光板保護フィルムは、偏光板の視認側やバックライト側に用いられることもできることから、紫外線吸収機能を付与することを目的として、紫外線吸収剤を含有してもよい。 (Ultraviolet absorber)
Since the polarizing plate protective film can be used on the viewing side or the backlight side of the polarizing plate, it may contain an ultraviolet absorber for the purpose of imparting an ultraviolet absorbing function.
　紫外線吸収剤としては、特に限定されないが、例えばベンゾトリアゾール系、２－ヒドロキシベンゾフェノン系又はサリチル酸フェニルエステル系等の紫外線吸収剤が挙げられる。
　例えば２－（５－メチル－２－ヒドロキシフェニル）ベンゾトリアゾール、２－［２－ヒドロキシ－３，５－ビス（α，α－ジメチルベンジル）フェニル］－２Ｈ－ベンゾトリアゾール、２－（３，５－ジ－ｔ－ブチル－２－ヒドロキシフェニル）ベンゾトリアゾール等のトリアゾール類、２－ヒドロキシ－４－メトキシベンゾフェノン、２－ヒドロキシ－４－オクトキシベンゾフェノン及び２，２′－ジヒドロキシ－４－メトキシベンゾフェノン等のベンゾフェノン類を例示することができる。
　上記紫外線吸収剤は、一種単独で又は二種以上組み合わせて用いることができる。 The ultraviolet absorber is not particularly limited, but includes, for example, benzotriazole-based, 2-hydroxybenzophenone-based, and salicylic acid phenyl ester-based ultraviolet absorbers.
For example 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(3,5 triazoles such as -di-t-butyl-2-hydroxyphenyl)benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone and 2,2'-dihydroxy-4-methoxybenzophenone, etc. benzophenones can be exemplified.
The ultraviolet absorbers may be used singly or in combination of two or more.
　紫外線吸収剤の使用量は、紫外線吸収剤の種類、使用条件等により一様ではないが、一般には、基材ポリマー（樹脂）に対して、０．０５～１０質量％の範囲内、好ましくは０．１～５質量％の範囲内で添加される。 The amount of the ultraviolet absorber used varies depending on the type of ultraviolet absorber, usage conditions, etc., but is generally within the range of 0.05 to 10% by mass, preferably It is added within the range of 0.1 to 5% by mass.
　（微粒子）
　偏光板保護フィルムは、偏光板保護フィルムに滑り性を付与する微粒子を添加することが好ましい。
　特に、本発明に係る偏光板保護フィルム表面の滑り性を向上し、巻取り時の滑り性を向上し、傷の発生やブロッキングの発生を防止する観点からも、微粒子を添加することは有効である。 (fine particles)
The polarizing plate protective film preferably contains fine particles that impart lubricity to the polarizing plate protective film.
In particular, the addition of fine particles is effective from the viewpoint of improving the slipperiness of the surface of the polarizing plate protective film according to the present invention, improving the slipperiness during winding, and preventing the occurrence of scratches and blocking. be.
　微粒子としては、得られる偏光板保護フィルムの透明性を損なうことがなく、溶融時の耐熱性があれば無機微粒子又は有機微粒子どちらでもよいが、無機微粒子がより好ましい。
　これらの微粒子は、単独でも二種以上併用しても使用できる。 The fine particles may be either inorganic fine particles or organic fine particles as long as they do not impair the transparency of the obtained polarizing plate protective film and have heat resistance when melted, but inorganic fine particles are more preferable.
These fine particles can be used alone or in combination of two or more.
　粒径や形状（例えば針状と球状等）の異なる粒子を併用することで高度に透明性と滑り性を両立させることもできる。 By using particles with different particle sizes and shapes (for example, needle-like and spherical), it is possible to achieve both high transparency and slipperiness.
　上記微粒子を構成する化合物の中でも、前記シクロオレフィン系ポリマー、アクリル系ポリマーやセルロースエステル系ポリマーと屈折率が近いので透明性（ヘイズ）に優れる二酸化ケイ素が特に好ましく用いられる。 Among the compounds constituting the fine particles, silicon dioxide is particularly preferably used because it has a refractive index close to that of the cycloolefin-based polymer, acrylic polymer and cellulose ester-based polymer and has excellent transparency (haze).
　二酸化ケイ素の具体例としては、アエロジル（登録商標）２００Ｖ、アエロジル（登録商標）Ｒ９７２Ｖ、アエロジル（登録商標）Ｒ９７２、Ｒ９７４、Ｒ８１２、２００、３００、Ｒ２０２、ＯＸ５０、ＴＴ６００、ＮＡＸ５０（以上日本アエロジル株式会社製）、シーホスター（登録商標）ＫＥＰ－１０、シーホスター（登録商標）ＫＥＰ－３０、シーホスター（登録商標）ＫＥＰ－５０（以上、株式会社日本触媒製）、サイロホービック（登録商標）１００（富士シリシア株式会社製）、ニップシール（登録商標）Ｅ２２０Ａ（日本シリカ工業株式会社製）及びアドマファイン（登録商標）ＳＯ（株式会社アドマテックス製）等の商品名を有する市販品等が好ましく使用できる。 Specific examples of silicon dioxide include Aerosil (registered trademark) 200V, Aerosil (registered trademark) R972V, Aerosil (registered trademark) R972, R974, R812, 200, 300, R202, OX50, TT600, NAX50 (Nippon Aerosil Co., Ltd. ), Seahoster (registered trademark) KEP-10, Seahoster (registered trademark) KEP-30, Seahoster (registered trademark) KEP-50 (manufactured by Nippon Shokubai Co., Ltd.), Cylophobic (registered trademark) 100 (Fuji Silysia Co., Ltd.), Nip Seal (registered trademark) E220A (manufactured by Nippon Silica Kogyo Co., Ltd.), and ADMAFINE (registered trademark) SO (manufactured by Admatechs Co., Ltd.).
　粒子の形状としては、不定形、針状、扁平、球状等特に制限なく使用できるが、特に球状の粒子を用いると得られる偏光板保護フィルムの透明性が良好にできるので好ましい。 The shape of the particles may be irregular, needle-like, flat, spherical, or the like, without any particular limitation. Use of spherical particles is particularly preferable because the obtained polarizing plate protective film can have good transparency.
　粒子の大きさは、可視光の波長に近いと光が散乱し、透明性が悪くなるので、可視光の波長より小さいことが好ましく、さらに可視光の波長の１／２以下であることが好ましい。 If the particle size is close to the wavelength of visible light, the light will scatter and the transparency will deteriorate. .
　粒子の大きさが小さすぎると滑り性が改善されない場合があるので、８０～１８０ｎｍの範囲内であることが特に好ましい。
　なお、粒子の大きさとは、粒子が一次粒子の凝集体の場合は凝集体の大きさを意味する。
　また、粒子が球状でない場合は、その投影面積に相当する円の直径を意味する。 If the particle size is too small, the slipperiness may not be improved, so it is particularly preferred that the particle size is in the range of 80 to 180 nm.
The size of the particles means the size of the aggregate when the particles are aggregates of primary particles.
When the particles are not spherical, it means the diameter of a circle corresponding to their projected area.
　微粒子は、基材ポリマー（樹脂）に対して、０．０５～１０質量％の範囲内、好ましくは０．１～５質量％の範囲内で添加されることが好ましい。 The fine particles are preferably added within the range of 0.05 to 10% by mass, preferably within the range of 0.1 to 5% by mass, relative to the base polymer (resin).
６．偏光板保護フィルムの用途
　本発明の製造方法により作製された偏光板保護フィルムは、位相差フィルムとしても用いることができ、偏光板の保護フィルム等に好適に利用され、種々の光学測定装置及び液晶表示装置や有機エレクトロルミネッセンス表示装置等の表示装置に用いることができる。 6. Uses of polarizing plate protective film The polarizing plate protective film produced by the production method of the present invention can also be used as a retardation film, and is suitably used as a protective film for polarizing plates, etc., and is used in various optical measurement devices and liquid crystals. It can be used for display devices such as display devices and organic electroluminescence display devices.
７．その他
　（７．１）水の接触角（濡れ性）
　本発明においては、ポリビニルアルコール系フィルム（偏光フィルム）とシクロオレフィン系ポリマーを含有する偏光板保護フィルムとの接着性の観点から、下記測定条件下で、フィルムの水接触角は７５～８５°の範囲内であることが好ましい。 7. Others (7.1) Water contact angle (wettability)
In the present invention, from the viewpoint of adhesion between a polyvinyl alcohol film (polarizing film) and a polarizing plate protective film containing a cycloolefin polymer, the film has a water contact angle of 75 to 85° under the following measurement conditions. preferably within the range.
　（水接触角の測定）
　本発明においては、水接触角は、温度２３℃、相対湿度５５％の雰囲気下で試料を２４時間放置後、温度２３℃、相対湿度５５％の雰囲気下で、接触角計（協和界面科学株式会社製、商品名ＤｒｏｐＭａｓｔｅｒ　ＤＭ１００）を用いて、純水１μＬの滴下１分後で測定した。
　なお、５回測定を行い、測定値の平均値を、水接触角とした。 (Measurement of water contact angle)
In the present invention, the water contact angle was measured by a contact angle meter (Kyowa Interface Science Co., Ltd.) in an atmosphere of 23°C and 55% relative humidity after leaving the sample for 24 hours in an atmosphere of 23°C and 55% relative humidity. Using DropMaster DM100 (manufactured by the same company), measurement was performed 1 minute after dropping 1 μL of pure water.
In addition, the measurement was performed 5 times, and the average value of the measured values was taken as the water contact angle.
　（７．２）フィルムの表面層密度
　本発明においては、フィルムの表面層密度は、１．９～２．０ｇ／ｃｍ３であることがフィルムの接着性の観点から好ましい。
　ここで、本発明において「表面層密度」とは、表面から厚さ方向に１００ｎｍ（０．１μｍ）までの領域の単位体積当たりの平均密度をいう。
　平均密度は、特許第４９２１６１２号公報の段落［００１１］～［００１８］に記載のように、Ｘ線反射率法（ＸＲＲ）を用いて算出することができる。
　Ｘ線は、フィルムに対して非常に浅い角度で入射させると全反射される。
　入射Ｘ線の角度が全反射臨界角以上になると、フィルム内部にＸ線が侵入しフィルム表面や界面で透過波と反射波に分かれ、反射波は干渉する。
　全反射臨界角を解析することで、フィルムの密度を求めることができ、その各々の平均値をとることで平均密度を求めることができる。 (7.2) Surface Layer Density of Film In the present invention, the surface layer density of the film is preferably 1.9 to 2.0 g/cm 3 from the viewpoint of film adhesion.
Here, in the present invention, the term "surface layer density" refers to the average density per unit volume of a region up to 100 nm (0.1 µm) in the thickness direction from the surface.
The average density can be calculated using X-ray reflectometry (XRR) as described in paragraphs [0011] to [0018] of Japanese Patent No. 4921612.
X-rays are totally reflected when incident on the film at very shallow angles.
When the angle of incident X-rays exceeds the critical angle for total reflection, the X-rays enter the inside of the film and are divided into transmitted waves and reflected waves at the film surface and interfaces, and the reflected waves interfere with each other.
By analyzing the critical angle of total reflection, the density of the film can be obtained, and by taking the average value of each, the average density can be obtained.
　（Ｘ線反射率法（ＸＲＲ）による平均密度の測定方法）
　表面から厚さ方向に１００ｎｍ（０．１μｍ）までの領域における平均密度は、下記に示す測定条件にてＸ線の反射率を測定して全反射臨界角度θｃを求め、その値から密度ρを算出し、さらには、この密度ρについて、表面から厚さ方向に１００ｎｍ（０．１μｍ）までの領域における厚さ方向の分布（密度分布）を求め、この密度分布の平均値を平均密度として算出した。
　測定装置と測定条件は以下のとおりである。 (Method for measuring average density by X-ray reflectance method (XRR))
The average density in a region up to 100 nm (0.1 μm) in the thickness direction from the surface is obtained by measuring the X-ray reflectance under the measurement conditions shown below to determine the total reflection critical angle θc, and from that value, the density ρ is calculated. Further, for this density ρ, the distribution in the thickness direction (density distribution) in a region from the surface to 100 nm (0.1 μm) in the thickness direction is obtained, and the average value of this density distribution is calculated as the average density. did.
The measurement equipment and measurement conditions are as follows.
　測定装置：薄膜評価用試料水平型Ｘ線回折装置「ＳｍａｒｔＬａｂ」株式会社リガク製
　測定条件：
　　Ｘ線源；Ｃｕ-Ｋα１（波長：１．５４０５９Å）
　　光学系；並行ビーム光学系
　　入射側スリット系；Ｇｅ（２２０）２結晶、高さ制限スリット５ｍｍ、入射スリット０．０５ｍｍ
　　受光側スリット系；受光スリット　０．１０ｍｍ、ソーラースリット　５°
　　検出器；シンチレーションカウンター
　　管電圧・管電流；４５ｋＶ・２００ｍＡ
　　走査軸；２θ／θ
　　走査モード；連続スキャン
　　走査範囲；０．１-３．０ｄｅｇ．
　　走査速度；１ｄｅｇ．／ｍｉｎ．
　　サンプリング間隔；０．００２°／ｓｔｅｐ Measurement device: Sample horizontal X-ray diffraction device for thin film evaluation “SmartLab” manufactured by Rigaku Corporation Measurement conditions:
X-ray source; Cu-Kα1 (wavelength: 1.54059 Å)
Optical system: parallel beam optical system Incident side slit system: Ge (220) 2 crystal, height limiting slit 5 mm, incident slit 0.05 mm
Light-receiving side slit system; light-receiving slit 0.10 mm, solar slit 5°
Detector; scintillation counter Tube voltage/tube current; 45 kV/200 mA
Scanning axis; 2θ/θ
Scanning mode; continuous scanning Scanning range; 0.1-3.0 deg.
Scanning speed; 1 deg. /min.
Sampling interval; 0.002°/step
　（７．３）破断点応力
　破断点応力は、フィルムをある方向に引っ張り続けて破断が生じた際の力を示す指標であり、長手方向の破断点応力が高くなることにより、フィルムの搬送、加工工程での破断や変形を抑制できる。 (7.3) Breaking point stress Breaking point stress is an index that indicates the force when a film is continuously pulled in a certain direction to cause breakage. It is possible to suppress breakage and deformation in the processing process.
　本発明では、２段階目の延伸直前の残留溶媒量は０．１～０．５質量％の範囲内である必要があり、フィルム表面にできる高密度層の生成を抑制する観点では残留溶媒量が多いほど良いが、残留溶媒量が０．５質量％より多い状態でフィルムの延伸を行うと、できあがったフィルムに対して接着剤の浸透量が過剰になってしまいフィルムの強度が弱くなる。 In the present invention, the amount of residual solvent immediately before the second stage of stretching must be in the range of 0.1 to 0.5% by mass, and from the viewpoint of suppressing the formation of a high-density layer formed on the film surface However, if the film is stretched with a residual solvent amount of more than 0.5% by mass, the amount of the adhesive permeating into the finished film becomes excessive and the strength of the film becomes weak.
　本発明の製造方法においては、フィルムを下記式（１）を満たす搬送速度Ｖ２にて搬送し、２段階目の延伸直前の残留溶媒量を０．１～０．５質量％の範囲内にすることによって破断点応力を高めることができる。
　　式（１）：Ｖ１＜Ｖ２
　本発明においては、破断点応力は２．１～２．７ＧＰａの範囲内であることが好ましく、２．４～２．７ＧＰａであることが、フィルム強度の観点から好ましい。 In the production method of the present invention, the film is conveyed at a conveying speed V 2 that satisfies the following formula (1), and the residual solvent amount immediately before the second stage stretching is within the range of 0.1 to 0.5% by mass. By doing so, the stress at break can be increased.
Formula (1): V 1 < V 2
In the present invention, the stress at break is preferably in the range of 2.1 to 2.7 GPa, preferably 2.4 to 2.7 GPa from the viewpoint of film strength.
　（破断点応力の測定方法）
　本発明にかかる偏光板保護フィルムの破断点応力の測定は、具体的には偏光板保護フィルムを長さ７０ｍｍ（ＴＤ：幅手方向）×１０ｍｍ（ＭＤ：長手方向）の短冊形に切り出し、テンシロン引張試験機（オリエンテック社製、ＲＴＣ－１２２５Ａ）を用いて、室温２３℃、相対湿度５５％の雰囲気下で、初期引張チャック間距離５０ｍｍ、引張速度５０ｍｍ／分として引張試験を行って得られた荷重－歪曲線から求められるものである。 (Method for measuring stress at break)
Specifically, the breaking point stress of the polarizing plate protective film according to the present invention is measured by cutting the polarizing plate protective film into a strip having a length of 70 mm (TD: width direction) × 10 mm (MD: length direction), Using a tensile tester (RTC-1225A, manufactured by Orientec Co., Ltd.), a tensile test is performed at a room temperature of 23 ° C. and a relative humidity of 55% at an initial tension chuck distance of 50 mm and a tensile speed of 50 mm / min. It is obtained from the load-strain curve.
　なお、測定は、各サンプルについて５回ずつ行い、それらの平均値で評価を行う。
　このとき、偏光板保護フィルムの長手方向の破断点応力を２．１ＧＰa以上にすることによって、フィルムの長手方向に力がかかった際にも破断や変形を抑制することができ、フィルムの破断や変形に伴う収率の低下や、得られたフィルムの光学特性や品質の低下を抑制することが容易となる。 In addition, the measurement is performed five times for each sample, and the average value thereof is used for evaluation.
At this time, by setting the breaking point stress in the longitudinal direction of the polarizing plate protective film to 2.1 GPa or more, it is possible to suppress breakage and deformation even when force is applied to the film in the longitudinal direction. It becomes easy to suppress the deterioration of the yield due to the deformation and the deterioration of the optical properties and quality of the obtained film.
　以下、実施例を挙げて本発明を具体的に説明するが、本発明はこれらに限定されるものではない。なお、実施例において「部」又は「％」の表示を用いるが、特に断りがない限り「質量部」又は「質量％」を表す。 The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. In the examples, "parts" or "%" are used, but "mass parts" or "mass%" are indicated unless otherwise specified.
　＜偏光板保護フィルムの作製＞
　（偏光板保護フィルムＮｏ．１の作製）
　偏光板保護フィルムの製膜には、溶液流延製膜法を用いた。 <Preparation of polarizing plate protective film>
(Preparation of polarizing plate protective film No. 1)
A solution casting film forming method was used to form the polarizing plate protective film.
　［原反フィルム製造工程］
　（ドープ調製工程（Ｓ１））
　〈環状ポリオレフィン重合体Ｐ－１の合成〉
　精製トルエン１００質量部とノルボルネンカルボン酸メチルエステル１００質量部を撹拌装置に投入した。
　次いでトルエン中に溶解したエチルヘキサノエート－Ｎｉ２５ｍモル％（対モノマー質量）、トリ（ペンタフルオロフェニル）ボロン０．２２５モル％（対モノマー質量）及びトルエンに溶解したトリエチルアルミニウム０．２５モル％（対モノマー質量）を撹拌装置に投入した。
　室温で撹拌しながら１８時間反応させた。
　反応終了後、過剰のエタノール中に反応混合物を投入し、重合物沈殿を生成させた。
　沈殿を精製し得られた重合体（Ｐ－１）を真空乾燥で６５℃にて２４時間乾燥した。 [raw film manufacturing process]
(Dope preparation step (S1))
<Synthesis of cyclic polyolefin polymer P-1>
100 parts by mass of purified toluene and 100 parts by mass of norbornene carboxylic acid methyl ester were put into a stirring device.
Then ethylhexanoate-Ni 25mmol% (relative to monomer mass) dissolved in toluene, tri(pentafluorophenyl)boron 0.225mol% (relative to monomer mass) and triethylaluminum 0.25mol% dissolved in toluene ( mass relative to the monomer) was added to the stirrer.
The reaction was allowed to proceed for 18 hours with stirring at room temperature.
After completion of the reaction, the reaction mixture was poured into excess ethanol to form a polymer precipitate.
The polymer (P-1) obtained by purifying the precipitate was vacuum dried at 65° C. for 24 hours.
　〈ドープＤ－１の調製〉
　下記組成物１をミキシングタンクに投入し、撹拌して各成分を溶解した後、平均孔径３４μｍの濾紙及び平均孔径１０μｍの焼結金属フィルターでろ過してドープを調製した。 <Preparation of Dope D-1>
After the following composition 1 was put into a mixing tank and stirred to dissolve each component, the solution was filtered through a filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm to prepare a dope.
　（組成物１）
　環状ポリオレフィン重合体（Ｐ－１）　　　　１５０質量部
　ジクロロメタン　　　　　　　　　　　　　　３８０質量部
　メタノール　　　　　　　　　　　　　　　　　７０質量部 (Composition 1)
Cyclic polyolefin polymer (P-1) 150 parts by mass Dichloromethane 380 parts by mass Methanol 70 parts by mass
　次に上記方法で調製した環状ポリオレフィン溶液（ドープ）を含む下記組成物２を分散機に投入し、添加剤として微粒子分散液（Ｍ－１）を調製した。 Next, the following composition 2 containing the cyclic polyolefin solution (dope) prepared by the above method was put into a disperser to prepare a fine particle dispersion (M-1) as an additive.
　（組成物２）
　微粒子（アエロジルＲ８１２：日本アエロジル社製、一次平均粒子径：７ｎｍ、見掛け比重５０ｇ／Ｌ）
　　　　　　　　　　　　　　　　　　　　　　　　４質量部
　ジクロロメタン　　　　　　　　　　　　　　　７６質量部
　メタノール　　　　　　　　　　　　　　　　　１０質量部
　環状ポリオレフィン溶液（ドープＤ－１）　　　１０質量部 (Composition 2)
Fine particles (Aerosil R812: manufactured by Nippon Aerosil Co., Ltd., primary average particle size: 7 nm, apparent specific gravity 50 g / L)
4 parts by mass Dichloromethane 76 parts by mass Methanol 10 parts by mass Cyclic polyolefin solution (Dope D-1) 10 parts by mass
　上記環状ポリオレフィン溶液を１００質量部、微粒子分散液を０．７５質量部を混合し、製膜用ドープ（ポリマー（樹脂）組成物シクロオレフィン系ポリマー：ＣＯＰ）を調製した。 100 parts by mass of the cyclic polyolefin solution and 0.75 parts by mass of the fine particle dispersion were mixed to prepare a film-forming dope (polymer (resin) composition cycloolefin polymer: COP).
　（流延工程（Ｓ２））
　ドープ調製工程（Ｓ１）で調製されたドープ（ポリマー（樹脂）組成物シクロオレフィン系ポリマー：ＣＯＰ）を、加圧型定量ギアポンプを通して、導管によって流延ダイに送液し、無限に移送する回転駆動ステンレス鋼製エンドレスベルトよりなる支持体上の流延位置に流延ダイからドープを製膜ラインで、１８００ｍｍ幅で流延し、ドープが自己支持性を持つまで、支持体上で加熱し、支持体から剥離ローラーによってウェブが剥離可能になるまで溶媒を蒸発させることにより乾燥させ、ウェブを形成した。
　このとき、ドープの搬送速度Ｖ１は、４０［ｍ／分］であった。 (Casting step (S2))
The dope (polymer (resin) composition cycloolefin-based polymer: COP) prepared in the dope preparation step (S1) is passed through a pressurized metering gear pump to a casting die through a conduit, and is transported endlessly. The dope is cast from a casting die onto a casting position on a support made of a steel endless belt in a film production line with a width of 1800 mm, and heated on the support until the dope has self-supporting properties. A web was formed by drying by evaporating the solvent until the web could be peeled off by a peel roller.
At this time, the dope transport speed V1 was 40 [m / min].
　（剥離工程（Ｓ３））
　流延工程（Ｓ２）にて、ウェブを形成した後、ウェブを支持体から剥離ローラーによって自己支持性をもたせたまま剥離した。 (Peeling step (S3))
In the casting step (S2), after the web was formed, the web was peeled from the support by a peeling roller while maintaining self-supporting properties.
　（ウェブを流延直後のウェブ幅に対して１段階目の延伸をする工程（Ｓ４））
　ウェブを幅手保持しない状態で高温処理して、ウェブの密度を高め、ウェブを幅手方向に収縮させながら１段階目の延伸をした。
　このとき、１段階目の延伸の直前の残留溶媒量を測定したところ、１２質量％であった。
　また、延伸倍率１．５０倍にて実施した。 (Step (S4) of stretching the web in the first stage with respect to the width of the web immediately after casting)
The web was subjected to a high temperature treatment without being held laterally to increase the density of the web, and the web was stretched in the first stage while shrinking in the lateral direction.
At this time, when the amount of residual solvent immediately before the first stage of stretching was measured, it was 12% by mass.
Moreover, it implemented by the draw ratio of 1.50 times.
　（乾燥工程（Ｓ５））
　その後、ウェブを支持体上で加熱し、溶媒を蒸発させた。 (Drying step (S5))
The web was then heated on the support to evaporate the solvent.
　（第１切断工程（Ｓ６））
　延伸されたウェブの幅手方向の両端部を切断した。 (First cutting step (S6))
Both ends of the stretched web in the widthwise direction were cut.
　（第１巻取工程（Ｓ７））
　フィルムを、搬送速度Ｖ１（４０［ｍ／分］）にて搬送しながら巻取装置によって巻芯に巻き取った。
　初期張力は５０Ｎ、テーパー７０％、及びコーナー２５％にて実施した。 (First winding step (S7))
The film was wound around a core by a winding device while being conveyed at a conveying speed V 1 (40 [m/min]).
The initial tension was 50 N, taper 70%, and corner 25%.
　［加工工程］
　（２段階目の延伸工程（Ｓ９））
　その後、巻き取られた前記フィルムは、そのロール体から繰り出す工程（Ｓ８）を経て延伸装置内で搬送速度Ｖ２（６５［ｍ／分］）にて搬送しながら、２段階目の延伸をした。
　このとき、２段階目の延伸の直前の残留溶媒量を測定したところ、０．３０質量％であった。
　また、延伸倍率１．５０倍にて実施した。 [Process]
(Second stage stretching step (S9))
After that, the wound film was passed through the step (S8) of unwinding from the roll body, and was subjected to a second stage of stretching while being transported at a transport speed V 2 (65 [m/min]) in a stretching device. .
At this time, when the amount of residual solvent immediately before the second stage of stretching was measured, it was 0.30% by mass.
Moreover, it implemented by the draw ratio of 1.50 times.
　（第２切断工程（Ｓ１０））
　第１切断工程と同様に、延伸されたフィルムの幅手方向の両端部を切断した。 (Second cutting step (S10))
Both ends of the stretched film in the width direction were cut in the same manner as in the first cutting step.
　（第２巻取工程（Ｓ１１））
　上記のフィルムを巻き取った。
　初期張力は５０Ｎ、テーパー７０％、及びコーナー２５％にて実施した。 (Second winding step (S11))
The above film was wound up.
The initial tension was 50 N, taper 70%, and corner 25%.
　以上の工程により、偏光板保護フィルムＮｏ．１の作製を行った。
　なお、上記工程により作製された偏光板保護フィルムの膜厚は４０μｍであった。 Through the above steps, the polarizing plate protective film No. 1 was obtained. 1 was produced.
The film thickness of the polarizing plate protective film produced by the above process was 40 μm.
　また、作製された偏光板保護フィルムＮｏ．１について水接触角、フィルムの表面層密度及び破断点応力を測定し、各値について評価を行った。 In addition, the manufactured polarizing plate protective film No. The water contact angle, the surface layer density of the film, and the stress at break of film No. 1 were measured, and each value was evaluated.
　（偏光板保護フィルムＮｏ．２～１５の作製）
　原反フィルム製造工程における１段階目の延伸条件であるドープの搬送速度Ｖ１、１段階目の延伸直前の残留溶媒量及び延伸倍率並びに２段階目の延伸条件であるフィルムの搬送速度Ｖ２、２段階目の延伸直前の残留溶媒量及び延伸倍率を表Iのように変更した以外は、偏光板保護フィルムＮｏ．１の作製手順と同様にして偏光板保護フィルムＮｏ．２～１５の作製を行った。
　また、作製された偏光板保護フィルムＮｏ．２～１５について水接触角、フィルムの表面層密度及び破断点応力を測定し、各値について評価を行った。 (Preparation of polarizing plate protective film Nos. 2 to 15)
Dope transport speed V 1 , which is the first-stage stretching condition in the raw film manufacturing process, residual solvent amount and stretch ratio immediately before the first-stage stretching, and film transport speed V 2 , which is the second-stage stretching condition, Except for changing the amount of residual solvent and the draw ratio just before the second-stage drawing as shown in Table I, the polarizing plate protective film No. Polarizing plate protective film No. 1 was prepared in the same manner as in No. 1. 2 to 15 were produced.
Moreover, the prepared polarizing plate protective film No. The water contact angle, film surface layer density and breaking point stress were measured for 2 to 15, and each value was evaluated.
　［水接触角］
　（測定方法）
　水接触角は、温度２３℃、相対湿度５５％の雰囲気下で試料を２４時間放置後、温度２３℃、相対湿度５５％の雰囲気下で、接触角計（協和界面科学株式会社製、商品名ＤｒｏｐＭａｓｔｅｒ　ＤＭ１００）を用いて、純水１μＬの滴下１分後で測定した。
　なお、５回測定を行い、測定値の平均値を、水接触角とした。
　フィルムの表面層密度及び破断点応力の測定方法に関しては、前述したとおりなので省略する。
　それぞれの測定した値や、それらに対する評価は、表Iに示すとおりである。
　また、上記の評価基準を以下に示す。 [Water contact angle]
(Measuring method)
The water contact angle was measured by a contact angle meter (Kyowa Interface Science Co., Ltd., trade name Using DropMaster DM100), measurement was performed 1 minute after dropping 1 μL of pure water.
In addition, the measurement was performed 5 times, and the average value of the measured values was taken as the water contact angle.
The methods for measuring the surface layer density and the stress at break of the film are the same as described above, and are omitted here.
Each measured value and the evaluation for them are as shown in Table I.
In addition, the above evaluation criteria are shown below.
　（評価基準）
　〇：水接触角が７５～８５°の範囲内
　△：水接触角が８５°より大きく８８°以下
　×：水接触角が８８°より大きく９０°以下
　なお、上記の範囲外の値（７５°未満若しくは９０°より大きい値）については、測定値として算出されなかったため、上記評価の範囲から除いてある。 (Evaluation criteria)
○: The water contact angle is within the range of 75 to 85 ° △: The water contact angle is greater than 85 ° and 88 ° or less ×: The water contact angle is greater than 88 ° and 90 ° or less Note that the value outside the above range (75 ° less than or greater than 90°) were excluded from the above evaluation range because they were not calculated as measured values.
　［フィルムの表面層密度］
　（測定方法）
　フィルムの表面層密度の測定方法に関しては、前述したとおりなので省略する。 [Film Surface Layer Density]
(Measuring method)
The method for measuring the surface layer density of the film is the same as described above, so the description is omitted.
　（評価基準）
　〇：表面層密度が１．８～２．０ｇ／ｃｍ３の範囲内
　△：表面層密度が２．０ｇ／ｃｍ３より大きく２．１ｇ／ｃｍ３以下
　×：表面層密度が２．１ｇ／ｃｍ３より大きい
　なお、上記の範囲外の値（１．８ｇ／ｃｍ３未満の値）については、測定値として算出されなかったため、上記評価の範囲から除いてある。 (Evaluation criteria)
○: Surface layer density is in the range of 1.8 to 2.0 g/cm 3 △: Surface layer density is greater than 2.0 g/cm 3 and 2.1 g/cm 3 or less ×: Surface layer density is 2.1 g/cm 3 More than cm 3 Note that values outside the above range (values less than 1.8 g/cm 3 ) were not calculated as measured values, so they are excluded from the above evaluation range.
　［破断点応力］
　（測定方法）
　フィルムの破断点応力の測定方法に関しては、前述したとおりなので省略する。 [Breaking point stress]
(Measuring method)
The method for measuring the stress at break of the film is the same as described above, so the description is omitted.
　（評価基準）
　〇：破断点応力が２．４～２．７ＧＰａの範囲内
　△：破断点応力が２．１ＧＰａ以上２．４ＧＰａ未満
　×：破断点応力が２．１未満
　なお、上記の範囲外の値（２．７ＧＰａより大きい値）については、測定値として算出されなかったため、上記評価の範囲から除いてある。 (Evaluation criteria)
○: Breaking point stress is in the range of 2.4 to 2.7 GPa △: Breaking point stress is 2.1 GPa or more and less than 2.4 GPa ×: Breaking point stress is less than 2.1 A value outside the above range (2 .7 GPa) were excluded from the above evaluation range because they were not calculated as measured values.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　［接着性］
　（評価方法）
　また、得られた偏光板保護フィルムＮｏ．１～１５を用いて偏光板を以下の方法で作製し、偏光子層との接着性をそれぞれ評価した。 [Adhesiveness]
(Evaluation method)
Also, the obtained polarizing plate protective film No. Using Nos. 1 to 15, polarizing plates were produced by the following method, and the adhesiveness to the polarizer layer was evaluated.
　（偏光子層と偏光板保護フィルムとの接着性）
　（１）偏光子層（偏光フィルム）の作製
　厚さ７０μｍのポリビニルアルコール系フィルムを、３５℃の水で膨潤させた。
　上記のフィルムを、ヨウ素０．０７５ｇ、ヨウ化カリウム５ｇ及び水１００ｇからなる水溶液に６０秒間浸漬し、さらにヨウ化カリウム３ｇ、ホウ酸７．５ｇ及び水１００ｇからなる４５℃の水溶液に浸漬した。
　上記のフィルムを、延伸温度５５℃、延伸倍率５倍の条件で一軸延伸した。
　この一軸延伸フィルムを、水洗した後、乾燥させて、厚さ２０μｍの偏光子層（偏光フィルム：ポリビニルアルコール－ヨウ素系偏光子層）を得た。 (Adhesion between polarizer layer and polarizing plate protective film)
(1) Production of polarizer layer (polarizing film) A 70 µm-thick polyvinyl alcohol-based film was swollen with water at 35°C.
The above film was immersed in an aqueous solution of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and further immersed in an aqueous solution of 3 g of potassium iodide, 7.5 g of boric acid and 100 g of water at 45°C.
The above film was uniaxially stretched under conditions of a stretching temperature of 55° C. and a stretching ratio of 5 times.
This uniaxially stretched film was washed with water and then dried to obtain a 20 μm-thick polarizer layer (polarizing film: polyvinyl alcohol-iodine-based polarizer layer).
　（２）接着剤の調製
　（水系接着剤の調製）
　１００質量部の水に、アセトアセチル基変性ポリビニルアルコール〔日本合成化学工業（株）製「ゴーセファイマーＺ-２００」〕４質量部、グリオキシル酸ナトリウム〔日本合成化学工業（株）製「ＳＰＭ-０１」〕４質量部を溶解させて、水系接着剤Ａを調製した。 (2) Preparation of adhesive (Preparation of water-based adhesive)
To 100 parts by mass of water, 4 parts by mass of acetoacetyl group-modified polyvinyl alcohol ["GOSEFIMER Z-200" manufactured by Nippon Synthetic Chemical Industry Co., Ltd.], sodium glyoxylate ["SPM- 01"] was dissolved to prepare a water-based adhesive A.
　（紫外線硬化型接着剤の調製）
　下記の各成分を混合した後、脱泡して、紫外線硬化型接着剤を調製した。
　なお、トリアリールスルホニウムヘキサフルオロホスフェートは、５０％プロピレンカーボネート溶液として配合し、下記にはトリアリールスルホニウムヘキサフルオロホスフェートの固形分量を表示した。 (Preparation of UV curable adhesive)
After mixing each of the following components, defoaming was performed to prepare an ultraviolet curable adhesive.
The triarylsulfonium hexafluorophosphate was blended as a 50% propylene carbonate solution, and the solid content of the triarylsulfonium hexafluorophosphate is shown below.
　（成分）
　３，４－エポキシシクロヘキシルメチル－３，４－エポキシシクロヘキサンカルボキシレート　　　　　　　　　　　　　　　４５．０質量部
　エポリードＧＴ－３０１（ダイセル社製の脂環式エポキシ樹脂）
　　　　　　　　　　　　　　　　　　　　　　　　４０．０質量部
　１，４－ブタンジオールジグリシジルエーテル　　１５．０質量部
　トリアリールスルホニウムヘキサフルオロホスフェート
　　　　　　　　　　　　　　　　　　　　　　　　　２．３質量部
　９，１０－ジブトキシアントラセン　　　　　　　　０．１質量部
　１，４－ジエトキシナフタレン　　　　　　　　　　２．０質量部 (component)
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 45.0 parts by mass Epolead GT-301 (alicyclic epoxy resin manufactured by Daicel)
40.0 parts by mass 1,4-butanediol diglycidyl ether 15.0 parts by mass Triarylsulfonium hexafluorophosphate 2.3 parts by mass 9,10-dibutoxyanthracene 0.1 parts by mass 1,4-diethoxynaphthalene 2 .0 part by mass
　（３）偏光板の作製
　前記作製した光学フィルムＮｏ．１～１２を準備し、その表面にコロナ放電処理を施した。
　なお、コロナ放電処理の条件は、コロナ出力強度２．０ｋＷ、ライン速度１８ｍ／分とした。
　次いで、当該フィルムのコロナ放電処理面に、接着剤として水系接着剤を用いた場合は、上記水系接着剤の膜厚が約３μｍとなるようにバーコーターで塗工して接着剤層を形成した。
　また、接着剤として紫外線硬化型接着剤を用いた場合は、紫外線照射による硬化後の膜厚が約３μｍとなるようにバーコーターで塗工して接着剤層を形成した。 (3) Production of polarizing plate Optical film No. produced above. 1 to 12 were prepared and their surfaces were subjected to corona discharge treatment.
The conditions for the corona discharge treatment were a corona output intensity of 2.0 kW and a line speed of 18 m/min.
Next, when a water-based adhesive was used as the adhesive, the water-based adhesive was applied to the corona discharge-treated surface of the film with a bar coater so that the thickness of the water-based adhesive was about 3 μm to form an adhesive layer. .
When an ultraviolet curable adhesive was used as the adhesive, the adhesive layer was formed by coating with a bar coater so that the film thickness after curing by ultraviolet irradiation was about 3 μm.
　上記の操作により得られた接着剤層に、前記ポリビニルアルコール－ヨウ素系偏光子層を貼合した。
　偏光子層のもう一方の面にも同様にして、光学フィルムＮｏ．１～１２を貼合して、偏光板を作製した。 The polyvinyl alcohol-iodine polarizer layer was laminated to the adhesive layer obtained by the above operation.
On the other side of the polarizer layer, optical film no. 1 to 12 were laminated to prepare a polarizing plate.
　次いで、接着剤として紫外線硬化型接着剤を用いた場合には、貼り合わせた積層物の両面側から、ベルトコンベヤー付き紫外線照射装置（ランプは、フュージョンＵＶシステムズ社製のＤバルブを使用）を用いて、積算光量が７５０ｍＪ／ｃｍ２となるように紫外線を照射し、紫外線硬化型接着剤層を硬化させた。 Next, when an ultraviolet curable adhesive is used as the adhesive, an ultraviolet irradiation device with a belt conveyor (a lamp using a D bulb manufactured by Fusion UV Systems Co., Ltd.) is used from both sides of the laminated laminate. Then, ultraviolet rays were irradiated so that the integrated amount of light was 750 mJ/cm 2 to cure the ultraviolet curing adhesive layer.
　得られた積層物を、それぞれ９０℃のオーブンで１０分間乾燥させることにより、偏光板保護フィルムの積層構造を有する偏光板を得た。 Each of the obtained laminates was dried in an oven at 90°C for 10 minutes to obtain a polarizing plate having a laminated structure of polarizing plate protective films.
　（４）接着性の評価
　上記の操作によって得られた偏光板を用いて、当該偏光板保護フィルムと偏光子層との界面で剥離したときの剥離強度（接着性）を、２３℃・５５％ＲＨの環境下で、９０°ピール試験（ＪＩＳ　Ｚ０２３７：２００９に準拠）を、株式会社イマダ製９０°剥離試験治具（Ｐ９０‐２００Ｎ）により測定した。 (4) Evaluation of adhesiveness Using the polarizing plate obtained by the above operation, the peel strength (adhesiveness) when peeled at the interface between the polarizing plate protective film and the polarizer layer was measured at 23 ° C. and 55%. A 90° peel test (based on JIS Z0237:2009) was measured using a 90° peel test jig (P90-200N) manufactured by Imada Co., Ltd. under a RH environment.
　また、以下の評価基準により評価し、△以上であれば、良好と判断した。
　評価結果は表Iに示したとおりである。 In addition, evaluation was made according to the following evaluation criteria, and if it was Δ or above, it was judged to be good.
The evaluation results are shown in Table I.
　（評価基準）
　○：剥離強度が２．０（Ｎ／２５ｍｍ）以上
　△：剥離強度が１．０～２．０（Ｎ／２５ｍｍ）の範囲内
　×：剥離強度が１．０（Ｎ／２５ｍｍ）未満 (Evaluation criteria)
○: Peel strength is 2.0 (N / 25 mm) or more △: Peel strength is in the range of 1.0 to 2.0 (N / 25 mm) ×: Peel strength is less than 1.0 (N / 25 mm)
　表Iから明らかなように、総合的に実施例の方が比較例より優れていることが分かる。 As is clear from Table I, it can be seen that the examples are comprehensively superior to the comparative examples.
　ポリビニルアルコール系フィルムとの接着性が改良されたシクロオレフィン系ポリマーを含有する偏光板保護フィルムの製造方法を提供することができる。 It is possible to provide a method for producing a polarizing plate protective film containing a cycloolefin-based polymer with improved adhesiveness to a polyvinyl alcohol-based film.
　１、１ａ　攪拌装置（攪拌槽）
　２　流延ダイ
　３　支持体（エンドレスベルト、ドラム）
　３ａ、３ｂ　ロール
　４　剥離ローラー
　５　ウェブ
　６　延伸装置
　７　乾燥装置
　８　切断部
　９　巻取装置
　１０　延伸装置
　１１　切断部
　１２　巻取装置
　Ｆ　フィルム 1, 1a stirring device (stirring tank)
2 casting die 3 support (endless belt, drum)
3a, 3b Roll 4 Peeling Roller 5 Web 6 Stretching Device 7 Drying Device 8 Cutting Section 9 Winding Device 10 Stretching Device 11 Cutting Section 12 Winding Device F Film

Claims (3)

  1. 　シクロオレフィン系ポリマーを含有する偏光板保護フィルムの製造方法であって、
    　原反フィルム製造工程と加工工程を有し、
    　前記原反フィルム製造工程が、少なくとも、ドープを搬送速度Ｖ１にて支持体に流延してウェブを形成する工程と、前記ウェブを流延直後のウェブ幅に対して１段階目の延伸をする工程と、前記ウェブを乾燥して形成されたフィルムを巻き取る工程とからなり、
    　前記加工工程が、巻き取られた前記フィルムを、下記式（１）を満たす搬送速度Ｖ２にて搬送し、２段階目の延伸をする工程を有し、
    　　式（１）：Ｖ１＜Ｖ２
    　さらに、巻き取られたフィルムを、前記２段階目の延伸をする工程にて、巻取り幅に対して前記２段階目の延伸をする直前の残留溶媒量が０．１～０．５質量％の範囲内にて延伸する
    ことを特徴とする偏光板保護フィルムの製造方法。     A method for producing a polarizing plate protective film containing a cycloolefin polymer, comprising:
    It has a raw film manufacturing process and a processing process,
    The raw film manufacturing process includes at least a step of casting the dope onto a support at a conveying speed V1 to form a web, and a first-stage stretching of the web width immediately after casting the web. and winding a film formed by drying the web,
    The processing step includes a step of conveying the wound film at a conveying speed V2 that satisfies the following formula (1) and performing a second stage stretching,
    Formula (1): V 1 < V 2
    Furthermore, in the step of stretching the wound film in the second stage, the amount of residual solvent immediately before the second stage stretching with respect to the winding width is 0.1 to 0.5% by mass. A method for producing a polarizing plate protective film, characterized in that stretching is performed within the range of
  2. 　前記１段階目の延伸をする直前の残留溶媒量が１～１５質量％の範囲内であり、延伸倍率が１．１～２．０倍の範囲内である
    ことを特徴とする請求項１に記載の偏光板保護フィルムの製造方法。     2. The method according to claim 1, wherein the amount of residual solvent immediately before the first-stage stretching is in the range of 1 to 15% by mass, and the stretching ratio is in the range of 1.1 to 2.0 times. A method for producing the described polarizing plate protective film.
  3. 　前記２段階目の延伸をする工程における延伸倍率が１．１～２．０倍の範囲内である
    ことを特徴とする請求項１又は請求項２に記載の偏光板保護フィルムの製造方法。      3. The method for producing a polarizing plate protective film according to claim 1, wherein the stretching ratio in the step of stretching in the second stage is in the range of 1.1 to 2.0 times.
PCT/JP2022/009683 2021-04-06 2022-03-07 Production method for polarizing plate protection film WO2022215407A1 (en)

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JP2003337202A (en) * 2002-05-21 2003-11-28 Konica Minolta Holdings Inc Antireflection film and method of manufacturing display device and optical film having the same
JP2004133209A (en) * 2002-10-10 2004-04-30 Sekisui Chem Co Ltd Retardation film and method for manufacturing same
WO2013140501A1 (en) * 2012-03-19 2013-09-26 コニカミノルタ株式会社 Method for manufacturing stretched film, device for manufacturing stretched film, and stretched film manufacturing system
WO2013140453A1 (en) * 2012-03-22 2013-09-26 コニカミノルタ株式会社 Method for manufacturing long stretched film, and device for manufacturing long stretched film
JP2018054640A (en) * 2015-02-19 2018-04-05 コニカミノルタ株式会社 Optical film, production method of optical film, polarizing plate, and liquid crystal display device
JP2019120879A (en) * 2018-01-10 2019-07-22 コニカミノルタ株式会社 Oriented film and method of producing the same

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JP2003337202A (en) * 2002-05-21 2003-11-28 Konica Minolta Holdings Inc Antireflection film and method of manufacturing display device and optical film having the same
JP2004133209A (en) * 2002-10-10 2004-04-30 Sekisui Chem Co Ltd Retardation film and method for manufacturing same
WO2013140501A1 (en) * 2012-03-19 2013-09-26 コニカミノルタ株式会社 Method for manufacturing stretched film, device for manufacturing stretched film, and stretched film manufacturing system
WO2013140453A1 (en) * 2012-03-22 2013-09-26 コニカミノルタ株式会社 Method for manufacturing long stretched film, and device for manufacturing long stretched film
JP2018054640A (en) * 2015-02-19 2018-04-05 コニカミノルタ株式会社 Optical film, production method of optical film, polarizing plate, and liquid crystal display device
JP2019120879A (en) * 2018-01-10 2019-07-22 コニカミノルタ株式会社 Oriented film and method of producing the same

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