JP2014058393A - Core member for resin film original fabric, resin film original fabric using core member for resin film original fabric, and method for producing optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a core member capable suppressing charging of a wound resin film, and obtaining an optical film excellent in coating suitability of coating liquid and excellent in optical characteristics, when forming a functional layer by unwinding the resin film.SOLUTION: A core member for a resin film original fabric includes a cylindrical core, and conductive surface layers formed on the outer peripheral surface and the inner peripheral surface of the core, and surface roughness of the surface layer provided on the inner peripheral surface is larger than surface roughness of the surface layer provided on the outer peripheral surface.

Description

  TECHNICAL FIELD The present invention relates to a resin film original fabric core member, a resin film original fabric using the resin film original fabric core member, and an optical film manufacturing method.

  In recent years, liquid crystal display devices, plasma display devices, and the like are known as image display devices. In these image display devices, an optical film in which various functional layers are formed on a resin film is used. The resin film is generally used for storage and transportation as a resin film original film (film roll) obtained by winding a long film around a core member in a roll shape. And when using, a resin film is sequentially unwound from a resin film original fabric, and an above-mentioned functional layer is formed.

  Moreover, as a functional layer with which an optical film is provided, for example, a hard coat layer, an antireflection layer with an adjusted refractive index, an antiglare layer having a concavo-convex shape formed on the surface, and a liquid crystal layer with controlled orientation direction of liquid crystal molecules ( Optically anisotropic layers) and the like are known. Such a functional layer can be formed by applying a functional layer-forming coating solution containing a material constituting the functional layer to the surface of the resin film. In order to form a uniform functional layer, it is preferable that the coating solution is uniformly spread and spread on the resin film.

  As one of the techniques for facilitating spreading of the coating liquid on the film surface, Patent Document 1 discloses a cylindrical core in which an antistatic treatment is applied to the core surface layer or the entire core when winding a continuous belt-like film. The manufacturing method of the film original fabric which uses is disclosed. In the core member described in Patent Document 1, at least the outer peripheral surface is subjected to antistatic treatment, and the charging of the film is suppressed to make it easy to spread the coating liquid on the film surface.

JP 2007-176034 A

  By the way, in recent years, in order to suppress optical non-uniformity generated when the film absorbs moisture, a low moisture-permeable, low moisture-absorbing film (for example, an acrylic film) is required as a protective film for the polarizing plate. However, since such a low moisture permeability and low moisture absorption film has a low moisture content and is easily charged, it is more difficult to suppress charging when forming a functional layer than in the past. Therefore, even if it tries to suppress charging of the film using the core member described in Patent Document 1, charging cannot be sufficiently suppressed when the functional layer is formed, and the resulting optical film is caused by uneven coating. There is a problem that optical unevenness is likely to occur.

  The present invention has been made in view of the above-described conventional problems, can suppress charging of a wound resin film, and applies a coating liquid when unwinding the resin film to form a functional layer. It aims at providing the core member for resin film original fabrics which can obtain the optical film which was excellent excellently and excellent in the optical characteristic. Moreover, it aims at providing the method of manufacturing an optical film from the resin film original fabric provided with such a core member for resin film originals, and this resin film.

  A core member for a resin film original fabric (hereinafter also simply referred to as a core member) according to an embodiment of the present invention includes a cylindrical winding core, and a conductive surface layer formed on the outer peripheral surface and the inner peripheral surface of the winding core. The surface roughness of the surface layer provided on the inner peripheral surface is larger than the surface roughness of the surface layer provided on the outer peripheral surface.

  By having such a structure, the core member of the present invention can increase the specific surface area of the conductive surface layer as compared with the conventional case. Therefore, the core member of the present invention can suppress the charging of the wound resin film more than before, and the coating liquid is applied when the wound resin film is unwound to form the functional layer. Appropriateness can be improved, and an optical film excellent in optical properties can be obtained.

  The winding core preferably includes a fiber reinforced plastic.

  When the core includes fiber reinforced plastic, the core can be reduced in weight and strength.

  Moreover, the resin film original fabric of this invention is equipped with the said core member and the elongate resin film wound by roll shape on the outer peripheral surface of this core member, It is characterized by the above-mentioned.

  As for the resin film original fabric of this invention, the resin film is wound around the said core member. Therefore, charging of the wound resin film is suppressed. As a result, when the wound resin film is unwound to form the functional layer, it is possible to improve the coating suitability of the coating liquid and to obtain an optical film having excellent optical characteristics.

  The water absorption rate of the resin film at a temperature of 23 ° C. and a relative humidity of 75% is preferably 2.0% or less.

  Such a resin film having a low water absorption rate is generally easily charged, but the original film of the resin film of the present invention sufficiently suppresses charging even when such a low moisture absorption film is wound. Can do. Therefore, even when various functional layers are applied on the low moisture permeability and low moisture absorption film to form an optical film, the occurrence of optical unevenness can be sufficiently suppressed.

  Further, the method for producing an optical film of the present invention includes a step of unwinding a resin film from the raw resin film, and a step of forming a functional layer by applying a coating liquid on the unwound resin film. It is characterized by providing.

  In the method for producing an optical film of the present invention, the film is unwound from the original resin film. Since the unwound film is suppressed from being charged, the coating solution is excellent in coating suitability when the functional layer is formed. Therefore, an optical film having excellent optical characteristics can be obtained.

  The functional layer is preferably at least one selected from the group consisting of a hard coat layer, an antireflection layer, an antiglare layer, and a liquid crystal layer.

  In the method for producing an optical film of the present invention, a film unwound from the resin film original fabric is used. Since the unwound film is suppressed from being charged, the application suitability of the coating solution is excellent when forming a functional layer having these various functions. Therefore, an optical film having excellent optical characteristics and capable of exhibiting various functions can be obtained.

  According to the present invention, the charging of the wound resin film can be suppressed, and when the functional film is formed by unwinding the resin film, the optical film is excellent in coating application and has excellent optical characteristics. It is possible to provide a core member capable of obtaining the above, a resin film original having such a core member, and a method for producing an optical film from the resin film original.

FIG. 1 is a schematic diagram of a core member according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a resin film original fabric according to an embodiment of the present invention. FIG. 3 is a schematic view showing a basic configuration of a resin film manufacturing apparatus by a solution casting method. FIG. 4 is a schematic diagram showing a basic configuration of an optical film manufacturing apparatus.

  Hereinafter, although the form for implementing this invention is demonstrated in detail, this invention is not limited to these.

<Core material for resin film substrate>
FIG. 1 is a schematic schematic view of a core member (core member 10) for a resin film original fabric according to the present embodiment. FIG. 1 (a) is a perspective view for explaining the core member 10, and FIG. ) Is a front view for explaining the core member 10. As shown in FIG. 1A, the core member 10 of the present embodiment includes a cylindrical winding core 11 and a conductive surface layer (surface) formed on the outer peripheral surface and inner peripheral surface of the winding core 11. Layer 12 and surface layer 13). In the core member 10, the surface roughness of the surface layer 13 provided on the inner peripheral surface is larger than the surface roughness of the surface layer 12 provided on the outer peripheral surface.

(Winding core)
As shown in FIG. 1A, the winding core 11 has a cylindrical shape. Since the inside of the winding core 11 is hollow, it is relatively lightweight. In addition, since the winding core 11 is cylindrical, a rotating device that rotates the core member 10 is installed when the resin film is wound and the resin film is wound around the outer peripheral surface. Cheap.

  The material for the winding core 11 is not particularly limited. For example, paper, resin, metal, or the like can be used as the material of the winding core 11. Moreover, these materials may be used independently and may be used in combination of 2 or more type.

  When paper is used, a flat wound type is preferable from the viewpoint that the average surface roughness is appropriate. When resin is used, for example, polyethylene, polypropylene, vinyl chloride, ABS resin, epoxy resin, polyester resin, butadiene rubber, polystyrene, polyimide resin, polyamide resin, polyamideimide resin, acrylic resin, vinyl chloride, polyvinylidene chloride, polyurethane resin Etc. can be adopted. When a metal is used, for example, iron, aluminum, copper, titanium, lead, zinc, gold, nickel, chromium, tin, silver, palladium, platinum or the like can be employed.

  Moreover, as a material of the winding core 11, it is preferable to employ | adopt fiber reinforced plastic at the point which is lightweight and excellent in intensity | strength. Specifically, a glass fiber reinforced plastic combining the resin and glass fiber, or a carbon fiber reinforced plastic combining the resin and a carbon material such as carbon fiber or carbon black as a conductive agent is preferably employed. it can. Among these, it is preferable to use conductive carbon fiber reinforced plastic. By adopting conductive carbon fiber reinforced plastic, it is possible to move the resin film charge generated during storage of the resin film raw material or unwinding of the film to the winding core 11 and diffuse it in the winding core 11. Therefore, the effect of suppressing charging can be obtained. At this time, the charge generated in the resin film moves slowly to the winding core 11 via the surface layer 12 and the surface layer 13 described later, and it is considered that charging of the resin film can be suppressed. Moreover, it is thought that the electric charge which generate | occur | produces in the surface layer 12 and the surface layer 13 does not move to the wound resin film, but moves easily to the winding core 11 containing a conductive carbon fiber reinforced plastic. From these things, it is thought that the charge of a resin film can be suppressed. Therefore, when the resin film unwound from the original resin film is used, it is possible to produce an optical film in which the occurrence of image defects (optical unevenness) when used in an image display device is sufficiently suppressed. Specifically, an optical film in which generation of interference fringes such as moire fringes and glare is sufficiently suppressed can be manufactured.

  The magnitude | size of the winding core 11 is not specifically limited, For example, it can be set as internal diameter 100-1000mm, thickness 2-10mm, and length 1500-5000mm. By using such a core 11, for example, a long film having a width of 1000 to 4000 mm, a length of 2000 to 10000 m, and a thickness of 10 to 200 μm can be wound around the outer peripheral surface to form a film original.

  Conductive surface layers (a surface layer 12 and a surface layer 13 are formed on both surfaces (outer peripheral surface and inner peripheral surface) of the winding core 11. The core member 10 has an outer peripheral surface by including a conductive surface layer. The charging of the long film wound around the surface can be suppressed.

  It is preferable that the outer peripheral surface of the winding core 11 has a small surface roughness so that the film can be uniformly wound and the optical properties of the wound film are not deteriorated. For example, the surface roughness of the surface layer provided on the outer peripheral surface is preferably adjusted to 0.05 to 1.0 μm.

  On the other hand, the inner peripheral surface is adjusted so that the surface roughness is larger than the surface roughness of the outer peripheral surface. For example, the surface roughness of the surface layer provided on the inner peripheral surface is preferably adjusted to 1.0 μm to 30.0 μm, more preferably adjusted to 10.0 to 30.0 μm, and 20. More preferably, it is adjusted to 0 to 30.0 μm. Since the core member 10 is adjusted so that the surface roughness of the surface layer 13 provided on the inner peripheral surface is larger than the surface roughness of the surface layer 12 provided on the outer peripheral surface, the above-described conductivity is provided. The specific surface area of the surface layer can be made larger than before, and charging of the wound long film can be prevented.

  The method for adjusting the surface roughness of the surface layer 13 provided on the inner peripheral surface to be larger than the surface roughness of the surface layer 12 provided on the outer peripheral surface is not particularly limited. After adjusting the surface layer with the surface to the same degree of surface roughness, the inside of the core can be rubbed with a rod-like object wrapped with sandpaper, or sand with a particle size of 1 mm or less can be blown into the core. The surface roughness of the surface layer 13 provided on the peripheral surface can be increased. By such a method, for example, the specific surface area of the inner peripheral surface can be 1.1 to 2.0 times before and after adjusting the surface roughness.

  In addition, in the surface layer 13 provided in the internal peripheral surface, the place which adjusts surface roughness in this way is not specifically limited. That is, the surface roughness may be adjusted for a part of the surface layer 13 provided on the inner peripheral surface, or the surface roughness may be adjusted for all.

  The method for forming the conductive surface layer is not particularly limited. For example, a method of applying and drying a commercially available antistatic agent can be employed. As the antistatic agent, various ionic surfactants and nonionic surfactants typified by fluorine surfactants are generally used, but not limited thereto, and those having an antistatic effect. Any resin may be used, for example, a conductive polymer or a resin containing a metal can be employed. Specifically, MU-003 manufactured by Muromachi Technos Co., Ltd., MX-50 manufactured by Ichiko Engineering Co., Ltd., SL-10 manufactured by Achilles Co., Ltd., and the like can be employed.

The electrostatic effects of antistats, it is preferable that the surface resistance value and 1 × ¹⁰ 10 Ω or less, more preferably, to less 1 × 10 ⁸ Ω, be less 1 × 10 ⁷ Ω Further preferred. Therefore, the application thickness of the antistatic agent is not particularly limited as long as it can sufficiently exhibit the electrostatic effect. For example, the thickness can be 0.001 μm or more, preferably 0.01 μm or more, more preferably 0.1 μm or more. The surface resistance value here can be measured with a general resistivity meter, for example, using a portable surface resistivity / resistance meter 272A manufactured by Monroe Electronics.

  The core member 10 has a long resin film, which will be described later, wound around the outer peripheral surface in a roll shape to form a resin film original.

<Resin film stock>
FIG. 2 is a schematic schematic view of the resin film original fabric 20 of the present embodiment, FIG. 2 (a) is a schematic perspective view of the resin film original fabric 20, and FIG. FIG. 2C is a schematic perspective view illustrating a storage state of the resin film original fabric 20, and FIG. 2C is a schematic plan view illustrating a storage state of the resin film original fabric 20.

  As shown in FIG. 2A, the resin film original fabric 20 includes the above-described cylindrical core member 10 and a long resin film 21 wound around the outer peripheral surface of the core member 10 in a roll shape. Is provided. Further, as shown in FIGS. 2B and 2C, the resin film original fabric 20 is placed on a pedestal 23 provided with holding portions 22 that can pivotally support both ends of the core member 10. Saved by etc. In the conventional resin film original fabric, the resin film 21 is charged when the resin film original fabric 20 is stored or when the resin film 21 is unwound from the resin film original fabric 20 as described above. However, since the resin film original fabric 20 of the present embodiment uses the core member 10 described above, charging of the resin film 21 during such storage and unwinding is suppressed.

  The method for winding the resin film 21 around the core member 10 is not particularly limited, and can be wound by a conventionally known method. Specifically, it can be wound by a winding method such as a constant tension method, a constant torque method, a taper tension method, a program tension control method with a constant internal stress, or the like. The winding tension may be 30 to 400 N / m, and preferably 100 to 300 N / m.

  The size of the wound film is not particularly limited. For example, a long film having a width of 1000 to 4000 mm, a length of 1000 to 10000 m, and a thickness of 10 to 200 μm can be wound around the core member 10.

(Resin film)
It does not specifically limit as resin which comprises the resin film 21, For example, resin used as a base material of an optical film is mentioned. Specifically, for example, cellulose ester resins such as cellulose diacetate resin, cellulose triacetate resin, cellulose acetate butyrate resin, and cellulose acetate propionate resin; polyester resins such as polyethylene terephthalate resin and polyethylene naphthalate resin; Acrylic resins such as methyl methacrylate resin; polysulfone (including polyethersulfone) resin, polyethylene resin, polypropylene resin, cellophane, polyvinylidene chloride resin, polyvinyl alcohol resin, ethylene vinyl alcohol resin, syndiotactic polystyrene resin, cyclohexane Vinyl resins such as olefin resins and polymethylpentene resins; polycarbonate resins; polyarylate resins; polyether ketone trees ; It can be mentioned fluorine-based resin or the like; polyether ketone imide resin; polyamide resin. These raw materials may be used alone or in combination of two or more.

  Among these, it is preferable to use the resin film 21 having a water absorption rate of 2.0% or less at a temperature of 23 ° C. and a relative humidity of 75%, and more preferably using the resin film 21 having a water absorption rate of 1.5% or less. More preferably, the resin film 21 is 1.0% or less. The lower limit of the water absorption rate is not particularly limited, and can be appropriately set according to the required quality of the optical film. As described above, the resin film 21 having a water absorption rate of 2.0% or less is generally easily charged due to the low water absorption rate. However, since the resin film original fabric 20 of the present embodiment includes the core member 10 described above, Even when such a low moisture absorption film is wound around the core member 10, charging can be suppressed. Therefore, even when a low moisture permeability and low moisture absorption film is used as a protective film for a polarizing plate, the occurrence of optical unevenness can be sufficiently suppressed. The water absorption rate can be measured using an optical moisture meter (IM-3SCV MODEL-1900) manufactured by Fuji Work Co., Ltd.

  Examples of the resin film 21 having a water absorption rate of 2.0% or less include a polyacrylic resin (water absorption rate of about 1.2%) and a polyimide resin (water absorption rate of about 1.3%) containing polymethyl methacrylate. .

  The resin film 21 can be blended with a polymer additive as necessary. Thereby, when the functional layer mentioned later is formed on the resin film 21 unwound from the resin film original fabric 20, and an optical film is produced, the optical film which further suppressed generation | occurrence | production of an optical nonuniformity may be obtained.

  Although a polymer type additive is not specifically limited, For example, the thing etc. which can change the property to the thing suitable as a base material of an optical film by making it contain in the resin film 21 are mentioned. The polymer-based additive in the present embodiment includes those having a number average molecular weight of 200 or more and 50000 or less, preferably 300 or more and 10,000 or less, and more preferably 300 to 5000. Specific examples include relatively high molecular weight plasticizers such as polyester plasticizers and acrylic resin plasticizers. Among these, a polyester plasticizer is preferable.

  The polyester-based plasticizer is a product obtained by polycondensation of at least one polybasic acid and at least one polyhydric alcohol. Preferably, one polybasic acid and at least one dihydric alcohol are polymerized. Condensed. The dibasic acid may be either an aliphatic dibasic acid or an aromatic dibasic acid, and the aliphatic dibasic acid may be an aliphatic dicarboxylic acid such as malonic acid, succinic acid, glutaric acid, or adipine. Acid, sebacic acid, azelaic acid, cyclohexanedicarboxylic acid, maleic acid or fumaric acid are preferably used. As the aromatic dibasic acid, aromatic dicarboxylic acid phthalic acid, isophthalic acid, terephthalic acid, 1,5- Naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,8-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and the like are preferably used. The dihydric alcohol may be either a divalent aliphatic alcohol (aliphatic diol) or a divalent aromatic alcohol (aromatic ring-containing diol), but an aliphatic diol is preferred. Aliphatic diols include ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1, 4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,4-hexanediol, 1,4-cyclohexanediol or 1,4-cyclohexanedi Methanol is preferably used, and bisphenol A, 1,4-dihydroxyfunol or benzene-1,4-dimethanol is preferably used as the aromatic ring-containing diol. Moreover, although the terminal of a polyester plasticizer may be unsealed or sealed, when sealed, it contains an aliphatic group having 1 to 22 carbon atoms and an aromatic ring having 6 to 20 carbon atoms. It is preferably sealed with a substituent selected from a group, and among them, a monoalcohol residue or a monocarboxylic acid residue is preferable. As the monoalcohol residue, a substituted or unsubstituted monoalcohol residue having 1 to 30 carbon atoms is preferable. Methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, isopentanol, hexanol, isohexanol, cyclohexyl Alcohol, octanol, isooctanol, 2-ethylhexyl alcohol, nonyl alcohol, isononyl alcohol, tert-nonyl alcohol, decanol, dodecanol, dodecahexanol, aliphatic alcohol such as dodecaoctanol, allyl alcohol, oleyl alcohol, benzyl alcohol, 3- And substituted alcohols such as phenylpropanol, and methanol, ethanol, propanol, isopropanol, butano , Isobutanol, isopentanol, hexanol, isohexanol, cyclohexyl alcohol, isooctanol, 2-ethylhexyl alcohol, isononyl alcohol, oleyl alcohol, benzyl alcohol, methanol, ethanol, propanol, isobutanol, cyclohexyl Particularly preferred are alcohol, 2-ethylhexyl alcohol, isononyl alcohol, and benzyl alcohol. Moreover, as monocarboxylic acid used as a monocarboxylic acid residue, a C1-C30 substituted and unsubstituted monocarboxylic acid is preferable. These may be aliphatic monocarboxylic acids or aromatic ring-containing carboxylic acids. Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butanoic acid, caprylic acid, caproic acid, decanoic acid, dodecanoic acid, stearic acid, oleic acid, and preferred aromatic ring-containing monocarboxylic acids include, for example, Benzoic acid, p-tert-butylbenzoic acid, p-tert-amylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, normal propylbenzoic acid, aminobenzoic acid, acetoxybenzoic acid, etc. Each of these may be used alone or in combination of two or more.

(Method for producing resin film)
The resin film can be produced by, for example, a solution casting film forming method. Thereby, the film thickness is uniform and a resin film that can be suitably used as an optical film can be obtained.

  The solution casting film forming method is a casting process in which a resin solution (dope) in which the above resin is dissolved is cast on a traveling support to form a casting film (web), and the casting film is It is a film-forming method provided with the peeling process which peels from the said support body, and the drying process which dries the cast film which peeled. The resin film is produced, for example, by a resin film manufacturing apparatus 30 shown in FIG. FIG. 3 is a schematic view showing a basic configuration of a resin film manufacturing apparatus 30 by a solution casting method. The resin film manufacturing apparatus 30 shown in FIG. 3 is merely an example, and the configuration of the resin film manufacturing apparatus 30 is not limited thereto.

  As shown in FIG. 3, the resin film manufacturing apparatus 30 includes an endless belt support 31, a casting die 32, a peeling roller 33, a drying device 34, a winding device 35, and the like. The casting die 32 casts a resin solution 36 in which a resin is dissolved onto the surface of the endless belt support 31. The endless belt support 31 is supported by a pair of drive rollers and driven rollers so as to be driven. The resin solution 36 cast from the casting die 32 forms a casting film and is dried while being conveyed. The peeling roller 33 peels the dried cast film from the endless belt support 31. The peeled cast film is further dried by the drying device 34 and wound around the winding device 35 as a resin film.

  The resin film is not limited to a resin film formed by a solution casting film forming method, and may be a resin film formed by a melt casting film forming method.

  Moreover, the manufacturing method of a resin film original fabric is a method which can manufacture the resin film original fabric provided with the core member and the elongate resin film wound by roll shape on the outer peripheral surface of the core member. If there is, it will not be specifically limited. Specifically, a method of winding the resin film on the outer peripheral surface of the core member by rotating the core member and supplying the resin film onto the outer peripheral surface of the rotating core member can be mentioned. By doing so, the resin film original fabric by which the elongate resin film was wound by roll shape on the outer peripheral surface of the core member may be obtained. Specifically, the core member is installed in a winding device, and the core member is rotated by the winding device. More specifically, a method using a winding device 35 of a resin film manufacturing apparatus 30 by a solution casting film forming method as shown in FIG.

  The resin film is unwound from the resin film raw material thus manufactured, and a functional layer described later is formed to produce an optical film.

<Method for producing optical film>
The method for producing an optical film of the present embodiment includes a step of unwinding a resin film from the resin film original (unwinding step) and a step of forming a functional layer by applying a coating liquid on the unwound resin film. (Functional layer forming step). In addition, the manufacturing method of the optical film of this embodiment should just be a method provided with the unwinding process and a functional layer formation process, and it does not specifically limit about other processes.

  The optical film of this embodiment is produced using the optical film manufacturing apparatus 40 shown by FIG. 4, for example. FIG. 4 is a schematic view showing a basic configuration of the optical film manufacturing apparatus 40. The optical film manufacturing apparatus 40 shown in FIG. 4 is merely an example, and the configuration of the optical film manufacturing apparatus 40 is not limited to this. Different configurations can be employed depending on the type of functional layer to be formed.

  The optical film manufacturing apparatus 40 includes an unwinding device 41, a coating device 42, a temperature adjusting device (a temperature adjusting device 43 and a temperature adjusting device 44), a curing device 45, and a winding device 46. The unwinding process is performed by the unwinding apparatus 41, and the functional layer forming process is performed by the coating apparatus 42. Depending on the type of coating solution, the temperature adjustment device and the curing device 45 may be omitted.

  For example, the unwinding device 41 unwinds the resin film by rotating it from the raw resin film and supplies it to the coating device 42 and the like.

  The method for unwinding the resin is not particularly limited. For example, the resin film original fabric core member is installed in the unwinding device 41 and rotated in the direction opposite to the direction of winding the resin film. A method of unwinding a resin film or the like can be employed.

  The coating device 42 applies a coating solution containing a material constituting the functional layer to the surface of the resin film supplied from the unwinding device 41 to form the functional layer. The coating device 42 is not particularly limited. For example, a coating device 42 such as a gravure coater, spinner coater, wire bar coater, roll coater, reverse coater, extrusion coater, air doctor coater, die coater, dip coater, and inkjet device is used. Can do. When applying a plurality of layers on a resin film, multiple coatings may be applied simultaneously with a single coating device 42, such as an extrusion die having a multi-manifold. A plurality of them may be sequentially applied.

  The functional layer formed by applying the coating liquid is not particularly limited as long as it is a layer for exhibiting performance required as an optical film. Specifically, examples of the functional layer include a hard coat layer, an antireflection layer, an antiglare layer, and a liquid crystal layer (optically anisotropic layer). The optical film may be one in which one of these functional layers is formed on a resin film, or may be a laminate of two or more functional layers.

(Hard coat layer)
The hard coat layer is a layer for improving the scratch resistance of the film. The hard coat layer is preferably an actinic radiation curable resin layer, for example. The actinic radiation curable resin layer refers to a layer mainly composed of actinic radiation curable resin, which is a resin that cures through a crosslinking reaction or the like by irradiation with actinic rays such as ultraviolet rays or electron beams.

  Examples of the actinic radiation curable resin include a resin containing a monomer having an ethylenically unsaturated double bond. These are cured by irradiating active rays such as ultraviolet rays and electron beams. Examples of the ultraviolet curable resin include an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, and an ultraviolet curable epoxy resin. It is done.

  In general, UV curable urethane acrylate resins include 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter referred to as acrylate) in addition to products obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer. And those obtained by reacting an acrylate monomer having a hydroxyl group such as 2-hydroxypropyl acrylate, such as those described in JP-A-59-151110. Can do.

  Examples of the UV curable polyester acrylate resin include those that can be easily obtained by reacting a polyester polyol with 2-hydroxyethyl acrylate or 2-hydroxy acrylate monomer. For example, JP-A-59-151112 Can be mentioned.

  Examples of the ultraviolet curable epoxy acrylate resin include those produced by reacting an epoxy acrylate with an oligomer and adding a reactive diluent and a photoreaction initiator to the oligomer. For example, JP-A-1-105738 Can be mentioned.

  Examples of ultraviolet curable polyol acrylate resins include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate, and the like. it can.

(Antireflection layer)
The antireflection layer is a layer that is given a function by controlling the refractive index and layer thickness of each layer, such as increasing the refractive index of the hard coat layer and providing a low refractive index thin film thereon, and lowering the reflectance. This prevents the external object from being reflected on the display screen.

  Examples of the antireflection layer include those obtained by laminating a low refractive index layer having a refractive index smaller than that of the hard coat layer, those obtained by repeatedly laminating a low refractive index layer made of an inorganic compound and a high refractive index layer made of an inorganic compound, And so on.

  The material for forming the low refractive index layer is not particularly limited as long as it has a refractive index lower than that of the film or the hard coat layer. For example, resin materials such as ultraviolet curable acrylic resins, hollow silica or And hybrid materials in which inorganic fine particles such as colloidal silica are dispersed, sol-gel materials using metal alkoxides such as tetraethoxysilane, and the like.

(Anti-glare layer)
The anti-glare layer is a layer that reduces the visibility of the reflected image by blurring the outline of the image reflected on the surface so that the reflected image does not appear when using an image display device or the like. It is formed by providing appropriate irregularities on the surface.

  Examples of a method for forming such irregularities include the application of an antiglare layer to a film. Examples of the concavo-convex shape include a structure selected from a right cone, a diagonal cone, a pyramid, a diagonal pyramid, a wedge shape, a convex polygon, a hemisphere, and the like, and a structure having a partial shape thereof.

  The roughness of the uneven shape of the antiglare layer is preferably an arithmetic average roughness (Ra) defined by JIS B0601: 2001, more preferably 60 to 700 nm, and more preferably 80 to 400 nm. When Ra is less than 60 nm, the antiglare effect tends to be weakened, and when Ra exceeds 700 nm, there is a tendency to receive an impression that is too rough visually. In addition, Ra can be measured with an optical interference type surface roughness measuring instrument, and can be measured using, for example, an optical interference type surface roughness meter RST / PLUS (manufactured by WYKO).

(Liquid crystal layer (optically anisotropic layer))
The liquid crystal layer (optically anisotropic layer) is a layer obtained by applying and fixing liquid crystal molecules on a film, and is a layer for imparting optical anisotropy to the film.

  The liquid crystal material constituting the liquid crystal layer is not particularly limited. For example, a liquid crystal compound having a rod-like molecular structure or a liquid crystal compound having a disc-like molecular structure (also referred to as a discotic liquid crystal compound) is used. Can do. As such a liquid crystalline compound, the compounds described in JP-A-2006-285187 can be used, and the orientation direction of the liquid crystalline compound can be appropriately adjusted depending on the application.

  Since the film unwound by the unwinding device 41 is wound around the resin film original provided with the core member described above, charging of the film is suppressed. Therefore, the coating apparatus 42 can apply | coat the coating liquid for forming various functional layers uniformly.

  The temperature adjusting device performs a heat treatment or a cooling treatment on the coating liquid layer applied on the resin film. For example, the temperature adjustment device 43 heats and dries the coating solution applied on the resin film. Next, the temperature adjusting device 44 cools the coating solution to increase the viscosity of the coating solution layer before the curing process.

  The curing device 45 performs a curing process on the coating liquid layer that has been subjected to the heat treatment or the cooling process. For example, the curing device 45 irradiates the layer of the coating liquid with an active ray such as ultraviolet rays, or performs a heat treatment at a temperature higher than the heating by the temperature adjusting device 43 described above. Thereby, the optical film in which the functional layer was formed on the resin film is obtained.

  The winding device 46 winds up the obtained optical film. The winding device 46 is, for example, a device that includes a rotatable winding roller and winds the optical film by rotating the winding roller. The wound optical film has a uniform functional layer and can exhibit various functions.

  The tension during winding can be 30 to 400 N / m, and preferably 10 to 300 N / m.

  The obtained optical film is made into a polarizing plate by being attached to a polarizing element. Since this polarizing plate uses the above optical film, the image unevenness using the polarizing plate is sufficiently suppressed.

  As the polarizing plate, for example, an optical film is preferably bonded to at least one surface of a polarizing element using a completely saponified polyvinyl alcohol aqueous solution. Further, the polarizing plate may be formed by attaching an optical film to one surface of the polarizing element, but the above optical film may be laminated on the other surface of the polarizing element. A transparent protective film may be laminated.

  As described above, the polarizing plate is obtained by laminating an optical film on at least one surface side of the polarizing element. When the optical film functions as an optical compensation film such as a retardation film, the optical film is preferably disposed so that the slow axis of the optical film is substantially parallel or perpendicular to the absorption axis of the polarizing element.

  Examples of the polarizing element include a polyvinyl alcohol polarizing film. The polyvinyl alcohol polarizing film includes those obtained by dyeing iodine on a polyvinyl alcohol film and those obtained by dyeing a dichroic dye. Among these, as the polyvinyl alcohol film, a modified polyvinyl alcohol film modified with ethylene is preferably used.

  The liquid crystal display device includes a liquid crystal cell and two polarizing plates arranged so as to sandwich the liquid crystal cell, and at least one of the two polarizing plates is a polarizing plate. Note that the liquid crystal cell is a cell in which a liquid crystal substance is filled between a pair of electrodes, and by applying a voltage to the electrodes, the alignment state of the liquid crystal is changed and the amount of transmitted light is controlled. Since such a liquid crystal display device uses a polarizing plate, there is little optical unevenness.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

<Production of core member>
(Core A)
An insulating paper core having an inner diameter of 152 mm, an outer diameter of 165 mm, and a length of 1450 mm was prepared. Next, MU-003 (mixture of polyoxyethylene trialkyl ethers and fluorosurfactant) manufactured by Muromachi Technos Co., Ltd. was sprayed uniformly as an antistatic agent only on the outer peripheral surface, and the mixture was sprayed at 30 ° C. for 5 minutes. It dried and formed the electroconductive surface layer of thickness 2mm. No conductive surface layer was provided on the inner peripheral surface. The surface resistivity of the outer peripheral surface was 1 × 10 ⁷ Ω / cm ² , and the surface resistivity of the inner peripheral surface was 2 × 10 ¹⁴ Ω / cm ² . The surface roughness (Ra) of the outer peripheral surface was 0.3 μm, and the surface roughness of the inner surface was also 0.3 μm. The surface resistivity was measured using a resistivity meter (portable surface resistivity / resistance meter 272A manufactured by Monroe Electronics). The surface roughness was measured using a non-contact surface shape measuring instrument (NewView ^™ 7300) manufactured by Canon Inc.

(Core B)
A core made of an insulating glass fiber reinforced plastic core having an inner diameter of 152 mm, an outer diameter of 165 mm, and a length of 1450 mm (a core having a glass fiber ratio of 60% and other components of 40%) was prepared. Next, MU-003 (mixture of polyoxyethylene trialkyl ethers and fluorosurfactant) manufactured by Muromachi Technos Co., Ltd. was sprayed uniformly as an antistatic agent only on the outer peripheral surface, and the mixture was sprayed at 30 ° C. for 5 minutes. It dried and formed the electroconductive surface layer of thickness 2mm. No conductive surface layer was provided on the inner peripheral surface. The surface resistivity of the outer peripheral surface was 1 × 10 ⁷ Ω / cm ² , and the surface resistivity of the inner peripheral surface was 1 × 10 ¹⁴ Ω / cm ² . The surface roughness of the outer peripheral surface was 0.3 μm, and the surface roughness of the inner peripheral surface was also 0.3 μm.

(Core C)
A core made of an insulating glass fiber reinforced plastic core having an inner diameter of 152 mm, an outer diameter of 165 mm, and a length of 1450 mm (a core having a glass fiber ratio of 60% and other components of 40%) was prepared. Next, MU-003 (mixture of polyoxyethylene trialkyl ethers and a fluorosurfactant) manufactured by Muromachi Technos Co., Ltd. was sprayed uniformly on the outer peripheral surface and inner peripheral surface as an antistatic agent, and 30 ° C. And dried for 5 minutes to form a conductive surface layer having a thickness of 2 mm. The surface resistivity of the outer peripheral surface was 1 × 10 ⁷ Ω / cm, and the surface resistivity of the inner peripheral surface was 1 × 10 ⁷ Ω / cm. The surface roughness of the outer peripheral surface was 0.3 μm, and the surface roughness of the inner peripheral surface was also 3 μm.

(Core D)
A core made of an insulating glass fiber reinforced plastic core having an inner diameter of 152 mm, an outer diameter of 165 mm, and a length of 1450 mm (a core having a glass fiber ratio of 60% and other components of 40%) was prepared. The surface roughness was adjusted by rubbing the inner peripheral surface with a stick wound with sandpaper. Next, the specific surface area of the inner peripheral surface, and then on the outer peripheral surface and the inner peripheral surface, MU-003 (mixture of polyoxyethylene trialkyl ethers and fluorosurfactant) manufactured by Muromachi Technos Co., Ltd. ) Was sprayed uniformly and dried at 30 ° C. for 5 minutes to form a conductive surface layer having a thickness of 2 mm. The surface resistivity of the outer peripheral surface was 1 × 10 ⁷ Ω / cm, and the surface resistivity of the inner peripheral surface was 1 × 10 ⁵ Ω / cm. The surface roughness of the outer peripheral surface was 0.3 μm, and the surface roughness of the inner peripheral surface was 25 μm. The specific surface area of the inner circumferential surface before the adjustment of the surface roughness of the inner peripheral surface is 0.69 m ^2, specific surface area of the inner peripheral surface after adjusting was 1.38 m ^2.

(Core E)
A core made of a conductive carbon fiber reinforced plastic core having an inner diameter of 152 mm, an outer diameter of 165 mm, and a length of 1450 mm (the ratio of carbon fibers is 40% and the other components are 60%) was prepared. The surface roughness was adjusted by rubbing the inner peripheral surface with a stick wound with sandpaper. Next, the specific surface area of the inner peripheral surface, and then on the outer peripheral surface and the inner peripheral surface, MU-003 (a mixture of polyoxyethylene trialkyl ethers and a fluorosurfactant manufactured by Muromachi Technos Co., Ltd.) as an antistatic agent. ) Was sprayed uniformly and dried at 30 ° C. for 5 minutes to form a conductive surface layer having a thickness of 2 mm. The surface resistivity of the outer peripheral surface was 1 × 10 ⁷ Ω / cm, and the surface resistivity of the inner peripheral surface was 5 × 10 ⁴ Ω / cm. The surface roughness of the outer peripheral surface was 0.3 μm, and the surface roughness of the inner peripheral surface was 25 μm. The specific surface area of the inner peripheral surface before adjusting the surface roughness of the inner peripheral surface was, and the specific surface area of the inner peripheral surface after adjustment was 1.38 m ² .

<Preparation of the raw resin film>
An end of an acrylic film (thickness 60 μm, water absorption rate 1.2%) made of polymethyl methacrylate resin was fixed to each core member, and 3900 m was wound up to produce a resin film original. The tension during winding was 300 N / m.

<Preparation of optical film (formation of functional layer)>
Various functional layers were formed on each of the above resin film original fabrics by the following method.

<Formation of hard coat (HC) layer>
(Preparation of resin composition for forming hard coat layer)
A hard coat layer was prepared by dissolving 30 parts by mass of pentaerythritol triacrylate (PETA) and 1.5 parts by mass of a photopolymerization initiator (Irgacure 907 manufactured by Ciba Japan Co., Ltd.) in 73.5 parts by mass of methyl isobutyl ketone. A forming resin composition was obtained.

(Preparation of hard coat film)
The resin composition for forming a hard coat layer was bar-coated on each resin film unwound from each of the prepared resin film originals, and the solvent was removed by drying. Thereafter, ultraviolet irradiation is performed at an irradiation dose of about 20 mJ / cm ² using an ultraviolet irradiation device (Fusion UV manufactured by Fusion UV Systems Japan Co., Ltd., light source: H bulb), and the hard coat layer is semi-cured to obtain a film thickness. A 10 μm hard coat layer was formed on the resin film.

<Formation of antireflection (AR) layer>
(Preparation of low refractive index layer-forming resin composition)
Hollow silica dispersion (particle size 50 nm, solid content 20% by mass, solvent: methyl isobutyl ketone) 15 parts by mass, pentaerythritol triacrylate (PETA) 2 parts by mass and photopolymerization initiator (Irgacure manufactured by Ciba Japan Co., Ltd.) 127) 0.08 parts by mass of the compound was dissolved in 82.9 parts by mass of methyl isobutyl ketone to obtain a resin composition for forming a low refractive index layer.

(Preparation of antireflection film)
The resin composition for forming a hard coat layer was bar-coated on each resin film unwound from each of the prepared resin film originals, and the solvent was removed by drying. Thereafter, ultraviolet irradiation is performed at an irradiation dose of about 20 mJ / cm ² using an ultraviolet irradiation device (Fusion UV manufactured by Fusion UV Systems Japan Co., Ltd., light source: H bulb), and the hard coat layer is semi-cured to obtain a film thickness. A 10 μm hard coat layer was formed on the resin film.

Subsequently, the resin composition for forming a low refractive index layer was bar-coated, and the solvent was removed by drying. Thereafter, ultraviolet irradiation was performed using an ultraviolet irradiation device at an irradiation dose of about 200 mJ / cm ² , and the coating film was cured to produce a low refractive index layer of about 100 nm on the hard coat layer.

In this way, an antireflection layer composed of the hard coat layer and the low refractive index layer was formed on the resin film to obtain an antireflection film.
Example 1
An HC layer was formed on the resin film unwound from the resin film original fabric using the core D by the above method to produce an optical film.

(Example 2)
An optical film was produced in the same manner as in Example 1 except that the core E was used.

(Comparative Example 1)
An optical film was produced in the same manner as in Example 1 except that the core A was used.

(Comparative Example 2)
An optical film was produced in the same manner as in Example 1 except that Core B was used.

(Comparative Example 3)
An optical film was produced in the same manner as in Example 1 except that the core C was used.

(Example 3)
An optical film was produced by the same method as in Example 1 except that the AR layer was formed by the above method as the functional layer.
Example 4
An optical film was produced in the same manner as in Example 3 except that Core E was used.

(Comparative Example 4)
An optical film was produced in the same manner as in Example 3 except that Core A was used.

(Comparative Example 5)
An optical film was produced in the same manner as in Example 3 except that Core B was used.

(Comparative Example 6)
An optical film was produced in the same manner as in Example 3 except that Core C was used.

  About each optical film obtained by Examples 1-4 and Comparative Examples 1-6, the optical characteristic was evaluated along the following references | standards. The results are shown in Table 1.

(Interference fringe evaluation)
The black tape for preventing back surface reflection was stuck on the surface on the opposite side to the surface in which the functional layer of the obtained optical film was formed. The optical film in this state was visually observed from the surface side on which the functional layer was formed.
(Evaluation criteria)
○: No interference fringes were confirmed.
(Triangle | delta): The interference fringe was confirmed in the slight range.
X: Interference fringes were confirmed in a wide range.

(Evaluation with glare)
A black matrix pattern plate (105 ppi) in which a black matrix pattern was formed on a glass plate having a thickness of 0.7 mm was placed on a viewer (Light Viewer 7000PRO manufactured by Hakuba Photo Industry Co., Ltd.) with the pattern surface facing down. . On the black matrix pattern board, it mounted so that the surface on the opposite side to the surface in which the functional layer of the obtained optical film was formed may be contacted. In order to prevent the optical film from floating, the optical film was visually observed with the viewer operated in a dark room while lightly pressing the edge of the optical film with a finger.
(Evaluation criteria)
○: No glare was confirmed.
(Triangle | delta): The glare was confirmed in the slight range.
X: The glare was confirmed in a wide range.

  As shown in Table 1, when the optical functional layer is applied to the film wound around the core member of the present invention, when the hard coat layer is applied, or when the antireflection layer is applied, Coating unevenness due to charging did not occur, and generation of interference fringes and glare could be suppressed.

DESCRIPTION OF SYMBOLS 10 Core member 11 Winding core 12, 13 Surface layer 20 Resin film original fabric 21 Resin film 22 Holding part 23 Mounting frame 30 Resin film manufacturing apparatus 31 Endless belt support 32 Casting die 33 Peeling roller 34 Drying apparatus 35 Winding apparatus 36 Resin solution 40 Optical film manufacturing apparatus 41 Unwinding apparatus 42 Coating apparatus 43, 44 Temperature adjusting apparatus 45 Curing apparatus 46 Winding apparatus

Claims (7)

A cylindrical winding core, and a conductive surface layer formed on the outer peripheral surface and inner peripheral surface of the winding core,
The core member for resin film original fabric whose surface roughness of the surface layer provided in the said inner peripheral surface is larger than the surface roughness of the surface layer provided in the said outer peripheral surface.   The core member for a resin film original fabric according to claim 1, wherein the winding core includes a fiber reinforced plastic.   The core member for a resin film original fabric according to claim 2, wherein the winding core includes a carbon fiber reinforced plastic.   The resin film original fabric provided with the core member for resin film original fabrics of any one of Claims 1-3, and the elongate resin film wound by roll shape on the outer peripheral surface of this core member.   The resin film original fabric according to claim 4, wherein the resin film has a water absorption of 2.0% or less at a temperature of 23 ° C. and a relative humidity of 75%. A step of unwinding a resin film from the resin film original fabric according to claim 4 or 5,
Forming a functional layer by applying a coating solution on the unrolled resin film;
An optical film manufacturing method comprising: The method for producing an optical film according to claim 6, wherein the functional layer is at least one selected from the group consisting of a hard coat layer, an antireflection layer, an antiglare layer, and a liquid crystal layer.

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