WO2013161192A1

WO2013161192A1 - Resin film web and method for manufacturing optical film

Info

Publication number: WO2013161192A1
Application number: PCT/JP2013/002302
Authority: WO
Inventors: 昌弘大和田
Original assignee: コニカミノルタ株式会社
Priority date: 2012-04-24
Filing date: 2013-04-03
Publication date: 2013-10-31

Abstract

One aspect of the present invention is a resin film web provided with: a cylindrical core member; and a continuous resin film wrapped around, in a roll form, the outer circumferential surface of the core member, the resin film containing a polymer-based additive, and the core member being provided with an insulating layer, and a conducting layer positioned on the inside of the insulating layer.

Description

Resin film original and optical film manufacturing method

The present invention relates to a resin film original fabric and a method for producing an optical film.

In general, a resin film used for manufacturing an optical film used in an image display device such as a liquid crystal display device or a plasma display device is a resin film raw material obtained by winding a long one around a core member in a roll shape. (Film roll) is used for storage and transportation. And when using a resin film, it unwinds and uses the resin film from the resin film original fabric one by one.

In addition, as such an optical film, a film provided with a functional layer on the surface of a resin film is used in order to exhibit various functions. Examples of the functional layer include 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 (optically anisotropic layer) in which the orientation direction of liquid crystal molecules is controlled. Etc. Such a functional layer can be formed by applying a functional layer forming coating liquid containing a material constituting the functional layer to the surface of the resin film. In such a case, in order to form a uniform functional layer, it is required that the coating solution be uniformly applied and spread on the resin film. For example, it is necessary to suppress the occurrence of unevenness in the formed functional layer due to the phenomenon that the coating solution is repelled on the resin film, that is, the repelling.

As a method for suppressing such application repelling, for example, the method described in Patent Document 1 can be mentioned.

Patent Document 1 describes a method of manufacturing a film raw material that is wound using a cylindrical core in which an antistatic treatment is applied to the core surface layer or the entire core when winding a continuous band-shaped film. Yes. According to Patent Document 1, it is possible to provide a film that is not charged even when a continuous belt-like film is stored for a long period of time and does not generate repellency when an adhesive or paint is applied. Is disclosed.

Japanese Patent Laid-Open No. 2007-176034

An object of the present invention is to provide a resin film raw material capable of unwinding a resin film capable of producing an optical film in which the occurrence of an image defect is sufficiently suppressed when used in an image display device. Moreover, it aims at providing the manufacturing method of the optical film using such a resin film original fabric.

One aspect of the present invention includes a cylindrical core member and a long resin film wound in a roll around the outer peripheral surface of the core member, and the resin film contains a polymer additive. The core member includes an insulating layer and a conductive layer located inside the insulating layer.

In another aspect of the present invention, a step of unwinding the resin film from the original film of the resin film, and applying a coating liquid containing a material constituting the functional layer on the unwound resin film. And a step of forming the functional layer.

The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

FIG. 1 is a schematic view showing a resin film original fabric according to this embodiment. FIG. 2 is a schematic perspective view showing the core member of the resin film original fabric according to this embodiment. 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.

According to the study of the present inventor, in the case of the optical film provided with the functional layer as described above, the required quality is very high, and it is not sufficient to suppress the application repelling by the method described in Patent Document 1. Met. That is, when the obtained optical film was used for an image display device, it became clear that various image defects may occur. For example, in the case of an antireflection film, which is an optical film provided with an antireflection layer, it is not sufficient to suppress the application of repelling, and the antireflection performance greatly changes with only a slight uneven thickness of the antireflection layer. Resulting in. For this reason, in the image display device, there are cases where problems such as interference fringes such as moire fringes and color unevenness occur. In addition, when fine particles are dispersed to form an antiglare layer with irregularities formed on the surface, or when liquid crystal molecules are dispersed and the orientation direction is controlled to form an optically anisotropic layer, The influence of the thickness unevenness of these functional layers comes out. Further, in these cases, not only the influence of the thickness unevenness but also aggregation of fine particles and liquid crystal molecules and disturbance of the alignment direction of the liquid crystal molecules may occur as image defects.

In addition, the resin film may contain a polymer additive in order to adjust properties such as flexibility. In the case of a resin film containing such a polymer-based additive, the above-described defects related to image defects occurred more remarkably.

Therefore, as a result of examining the cause of the occurrence of image defects when used in an image display device, the present inventor can sufficiently generate image defects only by reducing the charge amount of the resin film that is the base material of the optical film. It was found to be insufficient to obtain an optical film that can be suppressed to a low level. And this inventor presumed that it was due to the nonuniformity of the charging of the resin film, and such charging nonuniformity occurred when the resin film original was stored or when the resin film was unwound from the resin film original.

Further, in the case of a resin film containing a polymer-based additive, the cause of the above-mentioned defects related to image defects more significantly is that such a resin film is a film that easily retains uneven charging. Conceivable. Also, the reason why non-uniform charging of a resin film containing a polymer additive is easily maintained is that the specific resistance (electrical resistivity) is different between the resin that is a component of the resin film and the polymer additive mixed in the resin film. It is considered that the charge is concentrated on the component having the smaller specific resistance, resulting in uneven charging. That is, it is considered that charging unevenness is easily maintained by mixing a polymer additive having a specific resistance different from that of the resin into the resin which is a component constituting the resin film.

Further, when the conductivity of the core member around which the resin film is wound is increased, for example, in the method described in Patent Document 1, when the conductivity is imparted as an antistatic treatment, the charge charged on the resin film Since it moves via a core member, it is thought that the charge amount of a resin film becomes low. If the conductivity of the core member is high, the charge amount of the resin film becomes very low, for example, approximately 0 kV. Even in such a case, it is conceivable that frictional charge or peeling charge occurs when the resin film original is stored or when the resin film is unwound from the resin film original. When such charging occurs, the generated charge moves between the core member and the resin film, and even if the charge is locally small, charging is generated or micro-charging unevenness occurs. This is considered to induce the occurrence of coating unevenness that can cause image defects.

On the other hand, if an insulating core member is used, the charge cannot move through the core member, so the resin film wound around the core member is considered to be charged at a very high potential. At this time, it is considered that the resin film is charged non-uniformly and local charging unevenness occurs, which causes uneven coating.

Also, a method of reducing the uneven charging generated in the resin film by applying a charge-removing treatment or a reverse charge to the resin film unwound from the resin film original fabric may be considered. Even if a reverse charge is applied to the resin film, it is difficult to eliminate the charging unevenness, and the charging unevenness accumulated in the resin film wound around the resin film original is unwound after unwinding the resin film. It was difficult to eliminate. Moreover, if the charge removal process is sufficiently performed, it may cause an increase in the size of equipment and a decrease in production speed.

Therefore, the present inventor has examined the configuration of the core member, so that the resin film unrolled from the resin film original wound around the resin film containing the polymer additive is charged unevenly. The inventors have arrived at a resin film raw material capable of sufficiently suppressing the occurrence of the above. That is, the present inventor manufactures an optical film by forming a functional layer on a resin film unwound from a resin film raw film obtained by winding a resin film containing a polymer additive. However, the inventors have arrived at a resin film original fabric from which an optical film in which the occurrence of image defects in the image display device is suppressed can be obtained.

Hereinafter, embodiments according to the present invention will be described, but the present invention is not limited thereto.

The resin film original fabric according to the embodiment of the present invention includes a cylindrical core member and a long resin film wound around the outer peripheral surface of the core member in a roll shape. And a polymer-based additive, wherein the core member includes an insulating layer and a conductive layer located inside the insulating layer. In addition, long means that length is about 5 times or more with respect to a width | variety, for example. And the elongate here means that the length of the resin film is about 5 times or more, preferably 10 times or more, with respect to the width of the resin film.

By using such a core member having an insulating layer on the outer peripheral side and a conductive layer on the inner side, the charge of the resin film generated when the resin film is stored or when the resin film is unwound is reduced. It is thought that it moves to the conductive layer of the member and diffuses into the conductive layer. At this time, since the charge generated in the resin film moves to the conductive layer through the insulating layer, it is considered that the charge moves slowly and the occurrence of uneven charging of the resin film can be suppressed. In addition, when the resin film is stored, even if charging or uneven charging occurs in the conductive layer, the insulating layer is applied to the resin film that is less conductive than the conductive layer. It is thought that it is difficult to move through. Furthermore, it is considered that the electric charge generated in the insulating layer does not move to the resin film but easily moves to the conductive layer having high conductivity. From these facts, it is considered that the charging amount of the resin film is reduced, and even when the resin film is charged, the uneven charging is sufficiently suppressed. From this, when the resin film unwound from the resin film original fabric is used, an optical film in which the occurrence of image defects when used in an image display device is sufficiently suppressed can be produced. Specifically, an optical film in which generation of interference fringes such as moire fringes and glare is sufficiently suppressed can be manufactured.

From the above, the resin film original as described above can unwind a resin film capable of producing an optical film in which the occurrence of image defects is sufficiently suppressed when used in an image display device.

Further, as described above, the resin film original is a film roll wound around the outer peripheral surface of the core member in a roll shape. Specifically, for example, the resin film original as shown in FIG. Etc. FIG. 1 is a schematic view showing a resin film original fabric 10 according to this embodiment. 1A is a schematic perspective view showing the resin film original fabric 10, and FIG. 1B is a schematic perspective view for explaining the storage state of the resin film original fabric 10, FIG. (C) is a top view for demonstrating the preservation | save state of the resin film original fabric 10. FIG.

As shown in FIG. 1A, the resin film original fabric 10 includes a cylindrical core member 11 and a long resin film 12 wound around the outer peripheral surface of the core member 11 in a roll shape. In addition, as shown in FIGS. 1B and 1C, the resin film original fabric 10 is stored on a gantry 15 provided with holding portions 14 that can pivotally support both ends of the core member 11. And the like. Thus, when the resin film original fabric 10 is stored or when the resin film 12 is fed out from the resin film original fabric 10, the resin film may be charged. The resin film original fabric according to the present embodiment can sufficiently suppress the occurrence of uneven charging in such a resin film.

First, the core member 11 of the resin film original fabric 10 will be described.

The core member is not particularly limited as long as it includes an insulating layer and a conductive layer located inside the insulating layer. Examples of the core member 11 include a core member including an insulating layer 21 and a conductive layer 22 positioned inside the insulating layer 21 as shown in FIG. FIG. 2 is a schematic perspective view showing the core member 11 of the raw resin film according to the present embodiment, and shows a cross section by cutting a part of the core member 11. FIG. 2 is a drawing for showing the positional relationship between the insulating layer and the conductive layer, and the thickness of each layer is not limited to the thickness shown in FIG.

Here, the insulating layer is an insulating layer, and specifically includes a layer having a surface resistivity of 10 ¹² Ω / cm ² or more. Moreover, a conductive layer is a layer which has electroconductivity, Specifically, the layer etc. whose surface resistivity is 10 < ⁹ > ohm / cm < ² > or less are mentioned. The surface resistivity here can be measured with a general resistivity meter, for example, using a portable surface resistivity / resistance meter 272A manufactured by Monroe Electronics.

Further, the core member 11 is not limited to the insulating layer 21 and the conductive layer 22 as shown in FIG. 2, and may include other layers. For example, another layer may be provided inside the conductive layer 22. The surface of the insulating layer 21 may be provided with a protective layer, a lubricant layer for improving lubricity, and the like.

Further, the core member is preferably such that the outermost layer is an insulating layer. By doing so, it becomes this insulating layer that is in direct contact with the resin film, the generation of uneven charging in the resin film can be further suppressed, and the effects of the present invention can be suitably exhibited. That is, when the resin film unwound from the raw resin film is used for the production of an optical film, the occurrence of image defects when the obtained optical film is used in an image display device can be further suppressed.

Moreover, it is preferable that the insulating layer and the conductive layer are in direct contact with the core member. By doing so, it is considered that charges generated in the resin film can easily move to the conductive layer through the insulating layer, and the effects of the present invention can be suitably exhibited.

The insulating layer is not particularly limited as long as it is an insulating layer. Specific examples include resin layers such as epoxy resins, polyurethane resins, polycarbonate resins, polyethylene resins, polypropylene resins, ABS resins, polyester resins, polystyrene resins, and acrylic resins. Among these, an epoxy resin layer is preferable from the viewpoint of durability.

The thickness of the insulating layer is not particularly limited, but is preferably 3 mm or less, and more preferably 0.5 mm or more and 2 mm or less. With such a thickness, the charge generated in the resin film can be more suitably transferred to the conductive layer through the insulating layer. That is, the effect that an insulating layer intervenes between the resin film and the conductive layer can be further exhibited.

The conductive layer is not particularly limited as long as it is a conductive layer. Specifically, it is generally used as the core member of the resin film raw material, and includes a core member having conductivity. More specifically, a fiber reinforced resin (FRP) including a resin containing a conductive material and fibers, a resin containing a conductive polymer, a metal, and the like can be given. Among these, an FRP layer containing a conductive material is preferable from the viewpoint of ease of production and handling. The resin is not particularly limited as long as it can be used as an FRP resin. Specifically, an epoxy resin etc. are mentioned. Moreover, the said fiber will not be specifically limited if it can be used as a fiber of FRP. Specifically, glass fiber etc. are mentioned. The conductive material is not particularly limited as long as it can be contained in FRP to obtain conductive FRP. For example, carbon fiber or carbon black carbon member, and ionic surface activity And antistatic agents such as nonionic surfactants. Moreover, these content is not specifically limited. Content of the said resin and the said fiber should just be the same composition as the cylindrical FRP layer used as a core member of a resin film original fabric, for example. Further, the content of the conductive material is not particularly limited as long as the FRP layer can exhibit conductivity while maintaining the strength that can be used as the core material. Moreover, the thickness of the said insulating layer should just be the thickness of the core member generally used, and is not specifically limited.

Alternatively, a method of applying the antistatic agent inside the core and drying it may be used. As the antistatic agent, various ionic surfactants and nonionic surfactants typified by fluorine surfactants are generally used. Specific examples of antistatic agents include Muromachi Technos Co., Ltd. MU-003 manufactured by Ichiko Engineering Co., Ltd., MX-50, SL-10 manufactured by Achilles Co., Ltd., and the like. The coating thickness of the antistatic agent is not particularly limited, but it is important that the thickness be sufficient to exert the electrostatic effect, and the thickness is 0.001 μm or more, preferably 0.01 μm or more, and most preferably 0.1 μm or more. It is good to form with.

The core member has a cylindrical shape as shown in FIG. If it is cylindrical, since the inside is hollow, the weight can be reduced. Moreover, when the inside is a hollow, it is easy to install a rotating device that rotates the core member when the resin film is wound up to form a resin film with the resin film wound around the outer peripheral surface.

Further, the core member manufacturing method is not particularly limited as long as it is a method capable of manufacturing a core member including an insulating layer and a conductive layer located inside the insulating layer. Specifically, a method of applying a coating liquid containing a resin constituting the insulating layer to the surface of the conductive layer as described above and drying the surface can be used. By doing so, an insulating layer can be formed on the surface of the insulating layer. In addition, after the drying, heat treatment may be performed for curing the insulating layer.

Next, the resin film 12 of the raw resin film 10 will be described.

The resin film is not particularly limited as long as it is a resin film containing a polymer additive. When a resin film original fabric in which a resin film containing such a polymer-based additive is wound around a core member is used to produce an optical film by forming a functional layer on the resin film unwound from the resin film original fabric The obtained optical film tended to be prone to image defects. Then, if it is the resin film original fabric which concerns on this embodiment, even if it uses the resin film containing a polymer-type additive as a resin film, it can manufacture the optical film by which generation | occurrence | production of the image defect was fully suppressed. it can.

In addition, examples of the resin film include a resin film used as a base material of an optical film, and specific examples include a cellulose ester resin-containing film and an acrylic resin-containing film. That is, examples include a cellulose ester resin-containing film and an acrylic resin-containing film containing a polymer additive. Among these, a cellulose ester-based resin-containing film containing a polymer-based additive is preferable in that an optical film having suitable properties and excellent optical properties can be produced as a substrate for an optical film. In addition, when the optical film is produced by forming the functional film on the resin film unwound from the resin film original by making the form of the resin film original according to the present embodiment, image defects are sufficiently generated. A suppressed optical film is obtained.

Further, the polymer-based additive is not particularly limited, and examples thereof include those that can be transformed into a material suitable for a substrate of an optical film by being contained in a resin film. The polymer additives in the present invention include those having a number average molecular weight of 200 or more and 50000 or less, preferably 300 or more and 10000 or less, and more preferably 300 or more and 5000 or less. 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 plasticizer is a polycondensation of at least one polybasic acid and at least one polyhydric alcohol, preferably a polycondensation of one dibasic acid and at least one dihydric alcohol. is there. 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 is preferably an aliphatic diol. 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. Further, the end of the polyester plasticizer may be unsealed or sealed, but in the case of sealing, 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. The monoalcohol residue is preferably a substituted or unsubstituted monoalcohol residue having 1 to 30 carbon atoms. 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, butanol , Isobutanol, isopentanol, hexanol, isohexanol, cyclohexyl alcohol, isooctanol, 2-ethylhexyl alcohol, isononyl alcohol, oleyl alcohol, benzyl alcohol, methanol, ethanol, propanol, isobutanol, cyclohexyl alcohol 2-ethylhexyl alcohol, isononyl alcohol, and benzyl alcohol are particularly preferable. The monocarboxylic acid used as the monocarboxylic acid residue is preferably a substituted or unsubstituted monocarboxylic acid having 1 to 30 carbon atoms. 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, and oleic acid. 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.

In addition, a resin film containing a polyester plasticizer has suitable properties as a substrate for an optical film. In addition, when the optical film is produced by forming the functional film on the resin film unwound from the resin film original by making the form of the resin film original according to the present embodiment, image defects are sufficiently generated. A suppressed optical film is obtained. In particular, in the case of a cellulose ester resin-containing film, a polyester plasticizer is preferable from the viewpoint of compatibility.

Moreover, as the resin film, for example, a resin film obtained by a solution casting film forming method or the like can be used. If it is such a resin film, a film thickness is uniform and it can be conveniently used as an optical film.

The solution casting film forming method is a casting process in which a resin solution (dope) in which a transparent resin is dissolved is cast on a traveling support to form a casting film (web), and the casting film 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. For example, it is performed by a resin film manufacturing apparatus using a solution casting film forming method as shown in FIG. In addition, as a manufacturing apparatus of a resin film, it is not limited to what is shown in FIG. 3, The thing of another structure may be sufficient. FIG. 3 is a schematic view showing a basic configuration of an apparatus for producing a resin film by a solution casting method. 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 (dope) 36 in which a transparent resin is dissolved onto the surface of the endless belt support 31. The endless belt support 31 is supported to be drivable by a pair of driving rollers and driven rollers, forms a casting film made of the resin solution 36 cast from the casting die 32, 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 the dried cast film is wound around the winding device 35 as a resin film. Since the resin film thus obtained is wound around the core member by the winding device 35, it is obtained as a resin film original.

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

Moreover, the manufacturing method of the said resin film original fabric is equipped with the said core member 11 as shown in FIG. 1, and the elongate resin film 12 wound by the outer peripheral surface of the core member 11 in roll shape. If the resin film original fabric can be manufactured, it will not specifically limit. 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 (film roll) by which the elongate resin film was wound by roll shape on the outer peripheral surface of the core member is obtained. Specifically, a method of installing a core member in a winding device and rotating the core member with the winding device can be used. More specifically, a method using a winding device of a resin film manufacturing apparatus by a solution casting film forming method as shown in FIG.

Moreover, the manufacturing method of the optical film which concerns on other one Embodiment of this invention comprises a functional layer on the unwinding process which unwinds the said resin film from the said resin film original fabric, and the unwinded resin film And a functional layer forming step of forming the functional layer by applying a coating liquid containing the material to be formed. According to such a manufacturing method, since an optical film is manufactured by forming a functional layer on the resin film unwound from the resin film original fabric, image defects are sufficiently generated when used in an image display device. A suppressed optical film can be produced.

The method for producing the optical film is not particularly limited as long as the method includes an unwinding step and a functional layer forming step.

The unwinding step is not particularly limited as long as the resin film is sequentially unwound from the resin film original. Specifically, a method of rotating the core member of the resin film original in the direction opposite to the direction of winding the resin film and unwinding the resin film from the resin film original can be mentioned. Specifically, a method in which a core member of a resin film original fabric is installed in an unwinding device, and the core member is rotated by the unwinding device.

Moreover, the said functional layer formation process will not be specifically limited if it is a process which can apply | coat the coating liquid containing the material which comprises a functional layer on the unwound resin film, and can form the said functional layer. . Depending on the type of coating solution, there may be a case where a heat treatment or a curing treatment is performed after the coating.

Further, the application method of the application liquid is not particularly limited, and a known application method can be used. Specific examples include a gravure coater, a spinner coater, a wire bar coater, a roll coater, a reverse coater, an extrusion coater, an air doctor coater, a die coater, a dip coater, and an ink jet method.

Moreover, as a specific example of the method for producing the optical film, for example, a method performed by an optical film producing apparatus as shown in FIG. In addition, the manufacturing apparatus of an optical film is not limited to what is shown in FIG. 4, The thing of another structure may be sufficient. Also, the configuration differs depending on the type of functional layer to be formed.

FIG. 4 is a schematic diagram showing a basic configuration of the optical film manufacturing apparatus 40. The optical film manufacturing apparatus 40 includes an unwinding device 41, a coating device 42,

temperature adjusting devices

43 and 44, a curing device 45, and a winding device 46.

The unwinding device 41 supplies a resin film to the coating device 42 and the like. The unwinding device 41 is a device that unwinds the resin film and supplies it to the coating device 42, for example, by rotating the resin film original.

The coating device 42 applies a coating solution containing a material constituting the functional layer onto the surface of the resin film supplied from the unwinding device 41. As the coating device 42, a general coating device can be used without limitation. In addition, when a plurality of layers are applied and formed on a resin film, multiple layers may be simultaneously applied by a single application device such as an extrusion die having a multi-manifold, or a coating device for applying one layer. You may make it apply | coat one by one in succession.

The

temperature adjusting devices

43 and 44 perform heat treatment or cooling treatment on the coating liquid layer applied on the resin film. For example, first, the coating liquid applied on the resin film is dried by heating with the temperature adjusting device 43. Then, it cools with the temperature control apparatus 44, and reduces the viscosity of a coating liquid layer before a hardening process.

The curing device 45 is applied on a resin film and subjected to a curing process on the coating liquid layer that has been subjected to the heat treatment or the cooling process. For example, actinic rays such as ultraviolet rays are irradiated, or heat treatment is performed at a temperature higher than that by the temperature adjusting device. By doing so, the optical film in which the functional layer was formed on the resin film is obtained.

The winding device 46 winds up the optical film obtained as described above. 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.

Further, the functional layer of the optical film is not particularly limited as long as it is a layer for forming on the resin film and exhibiting the performance required as the optical film. Specific examples include a hard coat layer, an antireflection layer, an antiglare layer, and a liquid crystal layer. Moreover, each functional layer will not be specifically limited if it is a layer respectively used as a functional layer of an optical film. The optical film may be one in which only one of these layers is formed on a resin film, or may be a laminate of two or more types of layers. If it is the manufacturing method of the optical film which concerns on this embodiment, even if it forms the functional layer which has such a various function, generation | occurrence | production of the image defect at the time of using for an image display apparatus was fully suppressed Can be manufactured. Therefore, it is possible to produce an optical film in which the occurrence of image defects is sufficiently suppressed and various functions can be exhibited.

Further, the obtained optical film is attached to a polarizing element to obtain a polarizing plate. That is, the polarizing plate includes a polarizing element and a transparent protective film disposed on the surface of the polarizing element, and the transparent protective film is the optical film. Such a polarizing plate uses the above optical film in which the occurrence of image defects is sufficiently suppressed when used in an image display device. For this reason, when this polarizing plate is used, an image display apparatus with few image defects is obtained.

As the polarizing plate, for example, a completely saponified polyvinyl alcohol aqueous solution is used on at least one surface of a polarizing element produced by immersing and stretching a polyvinyl alcohol film in an iodine solution. A laminate is preferred. Further, the polarizing plate may be formed by attaching an optical film to one surface of the polarizing element, but the optical film may be laminated on the other surface of the polarizing element, or another polarized light. A transparent protective film for a plate may be laminated.

The polarizing plate is obtained by laminating an optical film on at least one surface side of the polarizing element as described above. In that case, 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 orthogonal to the absorption axis of the polarizing element.

Further, specific examples of the polarizing element include, for example, a polyvinyl alcohol polarizing film. Polyvinyl alcohol polarizing films include those obtained by dyeing iodine on polyvinyl alcohol films and those obtained by dyeing dichroic dyes. As the polyvinyl alcohol film, a modified polyvinyl alcohol film modified with ethylene is preferably used.

The polarizing plate can be used for an image display device such as a liquid crystal display device. Such a 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 the polarizing plate. Can be mentioned. 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. Such a liquid crystal device is an image display device with few image defects since the polarizing plate is used.

Also, the image display device using the optical film is not limited to the liquid crystal display device, and becomes an image display device with few image defects.

This specification discloses various modes of technology as described above, and the main technologies are summarized below.

According to such a configuration, this resin film original fabric can unwind a resin film capable of producing an optical film in which occurrence of image defects is sufficiently suppressed when used in an image display device. That is, it is possible to provide a resin film raw material capable of unwinding a resin film that can produce an optical film in which the occurrence of an image defect is sufficiently suppressed when used in an image display device.

Also, in the resin film original fabric, the insulating layer is preferably the outermost layer of the core member.

According to such a configuration, when the resin film unwound from the resin film raw material is subjected to the production of an optical film, the occurrence of image defects when the obtained optical film is used in an image display device Can be further suppressed.

In the resin film original fabric, the resin film is preferably a cellulose ester resin-containing film.

According to such a configuration, an optical film in which image defects are sufficiently suppressed when a cellulose ester resin-containing film that is suitably used as a base material for an optical film is unwound as a resin film and used in an image display device. A film can be produced.

Further, in the resin film original fabric, the polymer additive contained in the resin film is preferably a polyester plasticizer.

When the resin film containing the polyester plasticizer is unwound from the original resin film and used for the production of an optical film, the obtained optical film is prone to image defects when used in an image display device. There was a problem. With respect to the problem of the resin film containing such a polyester-based plasticizer, an optical film in which the occurrence of image defects is sufficiently suppressed can be obtained if the resin film is wound around the core member.

According to such a configuration, it is possible to manufacture an optical film in which occurrence of image defects is sufficiently suppressed when used in an image display device.

In the method for producing an optical film, it is preferable that 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.

According to such a configuration, even if such a functional layer having various functions is formed, an optical film in which the occurrence of image defects when used in an image display device can be sufficiently suppressed can be produced. Therefore, it is possible to produce an optical film in which the occurrence of image defects is sufficiently suppressed and various functions can be exhibited.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

[Production of core member]
First, the production of the core member will be described.

The surface resistivity was measured using a resistivity meter (a portable surface resistivity / resistance meter 272A manufactured by Monroe Electronics).

(Core A)
As shown in FIG. 2, a core A having an insulating layer on the outermost surface and a conductive layer on the inside was fabricated.

Specifically, first, a thermosetting epoxy resin is used as the matrix resin, and a semi-cured sheet obtained by impregnating the glass resin and carbon roving (carbon fiber) with the matrix resin is wound around a mold. After being thermally cured, the FRP (fiber reinforced plastic) winding core (cylindrical FRP layer) having an inner diameter of 152 mm, an outer diameter of 165 mm, and a length of 1450 mm is separated from the mold. Prepared as a layer. As shown in Table 1, this surface resistivity was 7 × 10 ⁷ Ω / cm ² and was conductive. Next, a coating solution containing an epoxy resin was applied to the cylindrical FRP layer (inner layer) so that the thickness after drying was 2 mm and dried. By doing so, the thermosetting epoxy resin was apply | coated on the cylindrical FRP layer, and the epoxy resin layer with an average film thickness of 2 mm was formed as an insulating outer layer (outermost layer). As shown in Table 1, this surface resistivity was 2 × 10 ¹⁴ Ω / cm ² and was insulating.

(Core B)
A core B in which the outermost surface was a conductive layer and the inside was an insulating layer was produced.

First, an antistatic agent (MU-003 manufactured by Muromachi Technos Co., Ltd., a mixture of polyoxyethylene trialkyl ethers and a fluorosurfactant) is made of polycarbonate having an inner diameter of 152 mm, an outer diameter of 165 mm, and a length of 1450 mm. It sprayed uniformly on the surface of the core. Then, it was dried at 30 ° C. for 5 minutes. By doing so, an antistatic layer having an average film thickness of 0.1 μm was formed on the core. As shown in Table 1, this surface resistivity was 7 × 10 ⁷ Ω / cm ² and was conductive. As shown in Table 1, the surface resistivity of the polycarbonate core was 2 × 10 ¹⁴ Ω / cm ² and was insulative.

(Core C)
A core C in which the outermost surface was an insulating layer and the inside was also an insulating layer was produced.

Specifically, first, an FRP core (cylindrical FRP layer) having an inner diameter of 152 mm, an outer diameter of 165 mm, and a length of 1450 mm was prepared as an inner layer. The cylindrical FRP layer was formed only of glass fibers and matrix resin without using carbon roving. And as shown in Table 1, this surface resistivity was 2 × 10 ¹⁴ Ω / cm ² and was insulating. Next, a coating liquid containing an epoxy resin was applied to the cylindrical FRP layer (inner layer) so that the thickness after drying was 2 mm, and dried and cured. By doing so, an epoxy resin layer having an average film thickness of 2 mm was formed as an outer layer (outermost layer) on the cylindrical FRP layer. As shown in Table 1, this surface resistivity was 2 × 10 ¹⁴ Ω / cm ² and was insulating.

The surface resistivity of each layer is shown together with the materials in Table 1.

[Preparation of raw resin film]
<Resin film stock wound with a resin film containing a polymer additive>
(Preparation of polymer additives)
First, in a 2 L four-necked flask equipped with a thermometer, a stirrer, and a slow cooling tube, 251 g of 1,2-propylene glycol, 278 g of phthalic anhydride, 91 g of adipic acid, 610 g of benzoic acid, tetraisopropyl titanate as an esterification catalyst 0.191 g was charged. And it heated up gradually, stirring until it became 230 degreeC in nitrogen stream, and stirred at 230 degreeC for 15 hours. By doing so, the dehydration condensation reaction was advanced. Then, it depressurizingly distilled at 200 degreeC. By doing so, unreacted 1,2-propylene glycol and the like were removed, and a polyester-based additive (polyester plasticizer) was obtained.

(Preparation of dope)
First, in a sealable dissolution tank containing 440 parts by mass of methylene chloride and 40 parts by mass of ethanol, 100 parts by mass of cellulose ester resin triacetyl cellulose, 10 parts by mass of polyester additive, Tinuvin 109 (Ciba Japan Co., Ltd.) 1 part by mass of company) and 0.2 part by mass of silica particles (Aerosil 972V manufactured by Nippon Aerosil Co., Ltd.) were added. And after raising the liquid temperature to 80 ° C., the mixture was stirred for 3 hours. By doing so, the resin solution in which the cellulose ester resin was dissolved was obtained. Then, stirring was complete | finished and it was left until the liquid temperature became 43 degreeC. Then, the obtained resin solution was filtered using a filter paper having a filtration accuracy of 0.005 mm. Air bubbles in the resin solution were degassed by allowing the resin solution after filtration to stand overnight. Using the resin solution thus obtained as a dope, a resin film was produced as follows.

(Manufacture of resin film stock)
First, the temperature of the obtained dope was adjusted to 35 ° C., and the temperature of the endless belt support was adjusted to 25 ° C. And the dope was cast from the casting die to the endless belt support using the resin film manufacturing apparatus. By doing so, a web was formed on the endless belt support, and the web was transported while being dried so that the residual solvent amount at the time of peeling of the web was 100% by mass. Then, the web was peeled off as a film from the endless belt support, and the peeled film was conveyed while being further dried at 35 ° C. Thereafter, both end portions of the film were cut (slit) so as to form a film having a width of 1500 mm. Then, using a tenter type stretching apparatus, both ends of the film were gripped with clips and dried at a drying temperature (heat treatment temperature / stretching temperature) of 130 ° C. while maintaining the width. In addition, the residual solvent amount when starting this drying was 20 mass%. Then, it was made to dry for 15 minutes, conveying the inside of a 100 degreeC drying apparatus with many rolls. Then, both ends were cut (slit) so that a film with a width of 1330 mm was formed, and knurling with a width of 15 mm and a height of 10 μm was applied to both ends of the film. The knurling resin film was wound around the core members (cores A to C) for a length of 500 m at an initial winding tension of 220 N / m and a taper of 40%. By doing so, the resin film original fabric was obtained. The residual solvent amount of the resin film wound around the resin film original fabric was 0.2% by mass, and the film thickness was 40 μm.

<Resin film stock wound with a resin film containing no polymer-based additive>
First, in a sealable dissolution tank containing 440 parts by mass of methylene chloride and 40 parts by mass of ethanol, 100 parts by mass of cellulose ester-based triacetyl cellulose, 8 parts by mass of triphenyl phosphate, ethylphthalylethyl glycolate 2 Part by mass, 1 part by mass of Tinuvin 109 (manufactured by Ciba Japan Co., Ltd.), and 0.2 part by mass of silica particles (Aerosil 972V manufactured by Nippon Aerosil Co., Ltd.) were added. And after raising the liquid temperature to 80 ° C., the mixture was stirred for 3 hours. By doing so, the resin solution in which the cellulose ester resin was dissolved was obtained. Then, stirring was complete | finished and it was left until liquid temperature became 43 degreeC. Then, the obtained resin solution was filtered using a filter paper having a filtration accuracy of 0.005 mm. Air bubbles in the resin solution were degassed by allowing the resin solution after filtration to stand overnight. The resin solution thus obtained was produced in the same manner as the method for producing a resin film raw material wound with a resin film containing a polymer additive, except that the resin solution was used as a dope.

[Production of optical film (formation of functional layer)]
<Formation of hard coat (HC) layer>
(Preparation of resin composition for forming hard coat layer)
30 parts by mass of pentaerythritol triacrylate (PETA) and 1.5 parts by mass of a photopolymerization initiator (Irgacure 907 (trade name) manufactured by Ciba Japan KK) were dissolved in 73.5 parts by mass of methyl isobutyl ketone. A resin composition for forming a hard coat layer was obtained.

(Preparation of hard coat film)
The resin composition for forming a hard coat layer was bar-coated on a resin film that was unwound from (unrolled from) the original resin film, and the solvent was removed by drying. Thereafter, UV 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), the hard coat layer is semi-cured, and the film thickness is 10 μm. The hard coat layer was prepared on a 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.) 0.08 parts by mass of 127 (trade name) 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 resin composition for forming hard coat layer)
30 parts by mass of pentaerythritol triacrylate (PETA) and 1.5 parts by mass of a photopolymerization initiator (Irgacure 907 (trade name) manufactured by Ciba Japan KK) were dissolved in 73.5 parts by mass of methyl isobutyl ketone. A resin composition for forming a hard coat layer was obtained.

(Preparation of antireflection film)
The resin composition for forming a hard coat layer was bar-coated on a resin film that was unwound from (unrolled from) the original resin film, and the solvent was removed by drying. Thereafter, UV 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), the hard coat layer is semi-cured, and the film thickness is 10 μm. The hard coat layer was prepared on a resin film.

Next, 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 the ultraviolet irradiation apparatus at an irradiation dose of about 200 mJ / cm ² to cure the coating film, and a low refractive index layer having a thickness of about 100 nm was produced on the hard coat layer.

Thus, an antireflection layer composed of a hard coat layer and a low refractive index layer was formed on the resin film. The film in which the antireflection layer is formed on the resin film is an antireflection film.

<Formation of anti-glare (AG) layer>
(Preparation of antiglare layer forming resin composition)
Colloidal silica dispersion (average particle size 5 μm, solid content 50 mass%, solvent: methyl isobutyl ketone) 20 mass parts, pentaerythritol triacrylate (PETA) 85 mass parts, transparent fine particles (acrylic beads, particle size 3.5 μm) 5 parts by mass and 5 parts by mass of a photopolymerization initiator (Irgacure 184 (trade name) manufactured by Ciba Japan Co., Ltd.) were dissolved in a mixed solvent consisting of 40 parts by mass of toluene and 150 parts by mass of methyl isobutyl ketone to prevent A resin composition for forming a glare layer was obtained.

(Preparation of antiglare film)
The resin composition for forming an antiglare layer was bar-coated on a resin film unwound from (unrolled from) a resin film original, and the solvent was removed by drying. Then, ultraviolet rays are irradiated at an irradiation dose of about 100 mJ / cm ² using an ultraviolet irradiation device (Fusion UV manufactured by Fusion UV Systems Japan Co., Ltd., light source: H bulb), the coating film is cured, and the antiglare layer is resin. Made on film. A film in which an antiglare layer is formed on this resin film is an antiglare film.

<Creation of optically anisotropic film>
The alignment film coating solution A described in Example 1 of Japanese Patent Application Laid-Open No. 2004-125841 is continuously applied on a resin film unwound from the original film of the resin film (dried), dried, and dried to a thickness of 1 μm. An alignment film was formed. Next, a rubbing treatment was performed on the alignment film continuously in a direction of 45 ° with respect to the longitudinal direction of the transparent support.

Next, a coating solution having the same composition as the coating solution used when forming the optically anisotropic layer described in the above publication is continuously applied, dried and heated on the alignment film using a bar coater. (Orientation ripening) was further performed, and an optically anisotropic layer having a thickness of about 1 μm was formed by irradiation with an ultraviolet ray of 600 mJ / cm ^{2 in an} air atmosphere. The optically anisotropic layer had a slow axis in the direction of 45 ° with respect to the longitudinal direction of the transparent support, and the retardation value (Re550) at 550 nm was about 135 nm.

The film obtained as described above is a retardation plate (λ / 4 plate), which is an optically anisotropic film.

Various optical films were produced by the manufacturing method as described above. Specifically, as shown in Table 2, optical films according to Examples 1 to 4, Comparative Examples 1 to 8, and Reference Examples 1 to 3 were produced. More specifically, Example 1 and Comparative Examples 1 and 2 are hard coat films in which a hard coat (HC) layer is formed on the resin film unwound from the resin film original fabric by the above method. is there. Example 2, Comparative Examples 3 and 4, and Reference Examples 1 to 3 are antireflection films in which an antireflection (AR) layer is formed on the resin film unwound from the resin film original fabric by the above method. . Moreover, Example 3 and Comparative Examples 5 and 6 are antiglare films in which an antiglare (AG) layer is formed on the resin film unwound from the resin film original fabric by the above method. In addition, Example 4 and Comparative Examples 7 and 8 are optically anisotropic films in which an optically anisotropic layer is formed by the above-described method on a resin film that has been unwound from a raw resin film. In Examples 1 to 4 and Reference Example 1, the core A was used as the core member of the resin film original. In Comparative Examples 1, 3, 5, and 7 and Reference Example 2, the core B is used as the core member of the resin film original. Comparative Examples 2, 4, 6, 8 and Reference Example 3 use the core C as the core member of the resin film original. In Examples 1 to 4 and Comparative Examples 1 to 8, resin films containing polymer additives are used. Reference Examples 1 to 3 use resin films that do not contain polymer additives.

These optical films were evaluated according to the following criteria.

[Evaluation]
(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 (coating 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 (coating layer) was formed.

As a result, when the occurrence of interference fringes is not confirmed, it is evaluated as “◯”, and when the occurrence of interference fringes is slightly confirmed, it is evaluated as “△”, and the occurrence of interference fringes is observed in a wide range. When it was confirmed, it was evaluated as “×”.

(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. And it mounted so that the surface on the opposite side to the surface in which the functional layer (coating layer) of the obtained optical film was formed may be contacted on the black matrix pattern board. Then, the optical film was visually observed in a dark room with the viewer operated while lightly pressing the edge of the optical film with a finger so that the optical film did not float.

As a result, if glare is not confirmed, evaluate as `` ○ '', if slightly glare is confirmed, evaluate as `` △ '', if glare is confirmed in a wide range, Evaluated as “x”.

(Moire evaluation)
An optical film was bonded to the polarizing plate surface (viewing side) of an image display device (BRAVIA (KDL32EX700) manufactured by Sony Corporation) via an adhesive, and an image displayed on the image display device was visually confirmed.

As a result, when moire was not confirmed, it was evaluated as “◯”, when slightly moire was confirmed, “△”, and when moire was confirmed in a wide range, it was evaluated as “x”. .

These results are shown in Table 2 together with the types of resin film, core and functional layer. In addition, when a polymer-type additive is contained in the resin film, it shows as "contained", and when not containing, it shows as "not containing".

As can be seen from Table 2, when an optical film was produced using a resin film original fabric provided with a core A comprising an insulating layer and a conductive layer located inside the insulating layer (Examples 1 to 4) Can be obtained in which interference fringes, glare and moire are sufficiently suppressed regardless of the type of the functional layer of the optical film. In contrast, when the outermost layer is not the insulating layer but the core B of the conductive layer (Comparative Examples 1, 3, 5, and 7), or when the core C made of the insulating layer is used (Comparative Examples 2, 4, and 5). 6, 8), the occurrence of interference fringes, glare, and moire could not be sufficiently suppressed.

Further, in optical films having an optical function such as an antireflection film, an antiglare film, and an optically anisotropic film, the suppression of the occurrence of interference fringes, glare, and moire, which are the effects of the present invention, was remarkable. .

Further, when a resin film containing no polymer additive was used (Reference Examples 1 to 3), there was almost no significant difference depending on the core member. From this, it turned out that it is meaningful to use the core A in the resin film original fabric provided with the resin film containing the polymer-based additive.

According to the present invention, there is provided a resin film raw material capable of unwinding a resin film that can produce an optical film in which the occurrence of image defects when used in an image display device is sufficiently suppressed. Moreover, the manufacturing method of the optical film using such a resin film original fabric is provided.

Claims

A cylindrical core member, and a long resin film wound around the outer peripheral surface of the core member in a roll shape,
The resin film contains a polymer additive,
The said core member is equipped with an insulating layer and the conductive layer located inside the said insulating layer, The resin film original fabric characterized by the above-mentioned.
The resin film original fabric according to claim 1, wherein the insulating layer is an outermost layer of the core member.
The resin film original fabric according to claim 1 or 2, wherein the resin film is a cellulose ester resin-containing film.
The resin film original fabric according to any one of claims 1 to 3, wherein the polymer-based additive is a polyester-based plasticizer.
A step of unwinding the resin film from the resin film original fabric according to any one of claims 1 to 4,
Applying the coating liquid containing the material constituting the functional layer onto the unrolled resin film to form the functional layer. A method for producing an optical film, comprising:
The method for producing an optical film according to claim 5, 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.