JP6642611B2 - Transfer laminate for optical film - Google Patents

Description

  The present invention relates to an optical film transfer laminate having a transfer layer.

  2. Description of the Related Art In recent years, an optical film applied to a flat panel display or the like is provided with a retardation layer that imparts a desired retardation to transmitted light to secure desired optical characteristics (for example, see Patent Document 1). . In this type of optical film, an alignment film is formed on the surface of a substrate made of a transparent film or the like, and the liquid crystal material is cured by an alignment regulating force of the alignment film to form a retardation layer. Although the liquid crystal material applied to such a retardation layer usually has a positive wavelength dispersion characteristic, in recent years, a liquid crystal material having an inverse dispersion characteristic has been proposed (for example, see Patent Documents 2 and 3). . Here, the inverse dispersion characteristic is a wavelength dispersion characteristic in which the phase difference in transmitted light is smaller on the shorter wavelength side, and more specifically, the retardation (R450) at a wavelength of 450 nm and the retardation (R550) at a wavelength of 550 nm. Is R450 <R550.

  Further, in an image display panel, a method of improving various optical characteristics such as a viewing angle characteristic and a color using an A plate, a C plate and the like has been proposed. A device for optical compensation of an ISP liquid crystal display device using a C plate has been proposed. Here, the optical compensation is a configuration for reducing light leakage in an oblique direction from a linear polarizing plate during black display. The C plate is represented by nx = ny <nz or nx = ny> nz, where nx = ny <nz is a positive C plate and nx = ny> nz is a negative C plate. The A plate is represented by nx> ny = nz or nz = nx> ny, where nx> ny = nz is a positive A plate and nz = nx> ny is a negative A plate. Note that nx and ny (nx ≧ ny) are refractive indices in an in-plane direction, and nz is a refractive index in a thickness direction.

  Among these optical films, the positive A plate uses a liquid crystal material having a positive wavelength dispersion characteristic and a liquid crystal material having an inverse dispersion characteristic applied to the retardation layer, and has a positive wavelength dispersion characteristic and a reverse dispersion characteristic, respectively. Can be produced. Further, the positive C plate can be manufactured by applying a coating liquid of a so-called liquid crystal material for the C plate, followed by drying and curing. In a vertical alignment (VA) liquid crystal display device or the like, a liquid crystal material is vertically aligned by a vertical alignment film, and various devices for a vertical alignment film for a VA liquid crystal have been proposed.

  Now, such an optical film is produced, for example, by a transfer method using a transfer laminate for an optical film having a transfer layer that is transferred to an optical functional layer such as a linear polarizer that functions as a linear polarizer. You. The transfer method means that, for example, when a desired layer is formed on a predetermined base material, the desired layer is not directly formed on the base material but is temporarily released on a release support (support After the transfer laminate is prepared by laminating the layers on the substrate in a releasable manner, the layer formed on the support is finally laminated according to the process and demand. This is a method in which a desired layer is formed on a predetermined base material by bonding and laminating on a (substrate to be transferred) and then peeling and removing the support. It is considered that an optical film having a small overall thickness can be provided by producing an optical film by such a transfer method. The optical film manufactured by the transfer method is described in, for example, Patent Documents 5 and 6.

  However, as described above, when the optical film is manufactured by transfer, when the transfer laminate is transferred onto the transfer target, the transfer laminate is not cut off at the end of the portion to be transferred, and In other words, a so-called tearing-off (transfer failure) may occur in which an extra transfer laminate is left on the side of the transfer laminate. In particular, when the peel strength of the support base material is in a high-speed region, such as when an optical film is produced with high productivity, the problem of poor transfer has been prominent.

JP-A-10-68816 US Patent No. 8119026 JP 2010-522892 A JP 2006-520008 A JP 2005-49865 A JP 2007-156234 A

  The present invention has been proposed in view of such circumstances, and when an optical film is produced using an optical film transfer laminate having a transfer layer, the support substrate peeling rate is high. It is an object of the present invention to provide a transfer laminate for an optical film that can suppress the occurrence of transfer failure even in the case of a region.

  The present inventor has conducted intensive studies in order to solve the above-mentioned problems. As a result, in the transfer laminate for an optical film, the orientation film laminated on the support substrate is formed by curing an orientation film composition containing a surfactant containing fluorine at a predetermined ratio, thereby supporting the film. The present inventors have found that the peel strength when the body substrate is peeled at a high speed can be reduced and the occurrence of transfer failure of the transfer laminate can be effectively suppressed, and the present invention has been completed. That is, the present invention provides the following.

  (1) The present invention relates to a method for producing a transfer laminate for an optical film having a transfer layer, wherein a preparation step of preparing a support base material made of polyethylene terephthalate whose surface has not been subjected to an easy adhesion treatment, An alignment film forming step of forming an alignment film by coating an alignment film composition containing the contained surfactant at a ratio of 0.025% by mass or more and 0.1% by mass or less on the support substrate and curing the composition. And a phase difference layer forming step of forming a phase difference layer by coating and curing a liquid crystal composition containing a liquid crystal compound on the alignment film, and the alignment film formed in the alignment film forming step A method for producing a transfer laminate for optical films, wherein fluorine is present at the interface between the film and the support substrate.

  (2) The present invention is a method for producing an optical film, wherein an adhesive layer is provided on the retardation layer of the transfer laminate for optical film produced by the method for producing a transfer laminate for optical film according to claim 1. A film laminating step of laminating a reverse dispersion-stretched film via a polarizing plate laminating step of laminating a linear polarizing plate via an adhesive layer on the reverse dispersion-stretched film after the film laminating step, and the film laminating step And then transferring the transfer substrate to the reverse dispersion-stretched film by peeling the support base material from the alignment film.

  (3) The present invention relates to a transfer laminate for an optical film having a transfer layer, wherein the support base material made of polyethylene terephthalate, the surface of which is not subjected to an easy adhesion treatment, an alignment film, and a retardation layer. The alignment film is formed of a cured product of an alignment film composition containing a surfactant containing fluorine, and fluorine is present at an interface between the support substrate and the alignment film. And a transfer laminate for an optical film having a peel strength of 0.35 N / 50 mm or less when the support base material is peeled at a peel speed of 50 m / min.

  ADVANTAGE OF THE INVENTION According to the transfer laminated body for optical films which concerns on this invention, the peeling strength at the time of peeling a support base material at high speed can be weakened, and generation | occurrence | production of transfer failure with respect to a to-be-transferred body can be suppressed effectively.

FIG. 2 is a schematic cross-sectional view illustrating an example of a transfer laminate for an optical film. It is a flowchart which shows the flow of the preparation process of the transfer laminated body for optical films. It is a figure for explaining a flow which produces an optical film by a transfer method using a transfer layered product for optical films. It is a graph which shows the result when having measured the peeling strength when changing the peeling speed of a PET base material about the transfer laminated body for optical films of Examples 1-3 and Comparative Example 1.

Hereinafter, specific embodiments of the transfer laminate for optical films according to the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail in the following order. Note that the present invention is not limited to the following embodiments, and various changes can be made without changing the gist of the present invention.
1. 1. Structure of transfer laminate for optical film 2. About alignment film 3. Method for producing transfer laminate for optical film Method for producing optical film using transfer laminate for optical film

≪1. Structure of transfer laminate for optical film≫
FIG. 1 is a cross-sectional view schematically illustrating an example of an optical film transfer laminate 1 according to the present embodiment. As shown in FIG. 1, a transfer laminate 1 for an optical film has a support base material 11 made of polyethylene terephthalate (PET), an alignment film 12, and a retardation layer (liquid crystal layer) 13 laminated in this order. It is.

  The transfer laminate 1 for an optical film is transferred to, for example, an optical functional layer of a linear polarizing plate or an optical functional layer of a reverse dispersion stretched film or the like that imparts a phase difference of 波長 wavelength to transmitted light. This is a transfer laminate for an optical film having a transfer layer, that is, a transfer layer including a retardation layer 13 and an alignment film 12. In the transfer laminate 1 for an optical film, for example, a transfer layer is transferred by pasting a polymer film such as an inverse dispersion stretched film on the retardation layer 13 via an adhesive, and a linear polarizing plate is further pasted. By combining, a predetermined optical film can be produced. At this time, in producing the optical film, after the transfer layer is transferred to a substrate such as a reverse dispersion stretched film on the transfer laminate for optical film 1, only the support substrate having releasability is peeled off.

  In the transfer laminate for an optical film 1 according to the present embodiment, the alignment film 12 laminated on the support base material 11 cures the alignment film composition containing a surfactant containing fluorine at a predetermined ratio. It is characterized by being constituted by a cured product.

  In such a transfer laminate 1 for an optical film, the fluorine contained in the surfactant in the alignment film composition is present on the interface side of the alignment film 12 with the support substrate 11. Then, the peel strength of the support base material 11, more specifically, the peel strength when the support base material 11 is peeled at a high speed can be reduced. Thereby, even when the support base material 11 is peeled at a high speed, it is possible to effectively suppress the occurrence of transfer failure of the transfer laminate to the transfer object, and to manufacture an optical film with high productivity. can do.

<1-1. Support substrate>
The support base material 11 has a function of indicating the alignment film 12, and is a long film material made of polyethylene terephthalate (PET).

  The support substrate 11 functions as a releasable support in the transfer laminate 1 for an optical film, supports the alignment film 12 and the retardation layer 13 serving as a transfer layer, and has a corona discharge on its surface. A known easy adhesion treatment such as a treatment or a plasma treatment is not performed, and has an adhesive strength that can be peeled off to the alignment film 12.

  The thickness of the support substrate 11 is not particularly limited, but is preferably, for example, in the range of 20 μm to 200 μm. If the thickness of the support base material 11 is less than 20 μm, it may not be possible to impart the minimum necessary self-supporting property as a transfer laminate for an optical film, which is not preferable. On the other hand, when the thickness exceeds 200 μm, when the transfer laminate for an optical film is long, the transfer laminate for an optical film is cut and processed into a single sheet. In this case, it is not preferable because machining chips increase and the cutting blade wears quickly.

<1-2. Alignment film>
The alignment film 12 is obtained by applying a composition for an alignment film (alignment film composition) on the above-described support base material 11 and curing the composition, and exhibits an alignment regulating force. Here, the alignment regulating force means a function of, when a layer (retardation layer 13) made of a polymerizable liquid crystal compound (liquid crystal material) is formed on the alignment film 12, aligning (aligning) the liquid crystal compound in a predetermined direction. Say. The alignment film 12 can be formed by, for example, a photo-alignment method in which a photo-alignment material that exhibits photo-alignment by polarized light irradiation is used, and alignment is performed by light irradiation.

  The alignment film 12 is not particularly limited. For example, the alignment film 12 can be formed of a vertical alignment film that homeotropically aligns (vertical aligns) the molecules of the liquid crystal compound molecules in the retardation layer 13. As the vertical alignment film, various vertical alignment films applied to a VA liquid crystal display device or the like can be applied, and for example, an alignment film of a polyimide alignment film, an LB film, or the like can be applied.

  More specifically, as the vertical alignment film, for example, lecithin, silane-based surfactant, titanate-based surfactant, pyridinium salt-based polymer surfactant, silane coupling-based vertical alignment such as n-octadecyltriethoxysilane Film-forming compositions, such as soluble polyimides having long-chain alkyl groups and alicyclic structures in the side chains, and polyimide-based vertical alignment film compositions such as polyamic acids having long-chain alkyl groups and alicyclic structures in the side chains. It can be formed using a material. As the vertical alignment film composition, a polyimide vertical alignment film composition “JALS-2021” or “JALS-204” manufactured by JSR Corporation and “RN-1517” manufactured by Nissan Chemical Industries, Ltd. , "SE-1211" and "EXPOA-018".

  The solvent (diluting solvent) used in the alignment film composition is not particularly limited as long as it can dissolve the alignment material to a desired concentration. For example, hydrocarbon solvents such as benzene and hexane, methyl ethyl ketone, Ketone solvents such as methyl isobutyl ketone and cyclohexanone (CHN); ether solvents such as tetrahydrofuran, 1,2-dimethoxyethane and propylene glycol monoethyl ether (PGME); alkyl halide solvents such as chloroform and dichloromethane; methyl acetate Ester solvents such as ethyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate (PGMEA); amide solvents such as N, N-dimethylformamide; sulfoxide solvents such as dimethyl sulfoxide; anone solvents such as cyclohexane; Methanol, ethanol, isopropyl alcohol (hereinafter, referred to as. "IPA") can be exemplified an alcohol solvent such as. The solvent may be one kind or a mixed solvent of two or more kinds of solvents.

  Such an alignment film 12 composed of a vertical alignment film or the like is prepared by applying a coating liquid of an alignment film composition containing the above-described material to the support substrate 11, drying the coating liquid, and heating. You. The alignment film 12 is constituted by the cured product thus produced.

  Here, in the transfer laminate for an optical film 1 according to the present embodiment, the alignment film 12 is made of an alignment film composition containing a surfactant containing fluorine (fluorine-containing surfactant) at a predetermined ratio. It is characterized by becoming. Specifically, it is composed of an alignment film composition containing a fluorine-containing surfactant in a ratio of 0.025% by mass or more and 0.1% by mass or less in the composition.

  As described later in detail, according to the transfer laminate for an optical film 1 having such an alignment film 12, the peel strength of the support base material 11, specifically, when the support base material 11 is peeled at a high speed. To reduce the occurrence of transfer failure of the transfer laminate to the transfer target even when the support base material 11 is peeled at a high speed in order to increase productivity. Can be.

<1-3. Retardation Layer (Liquid Crystal Layer)>
The retardation layer (liquid crystal layer) 13 contains a polymerizable liquid crystal composition. The polymerizable liquid crystal composition contains a liquid crystal compound (rod compound) having liquid crystallinity and having a polymerizable functional group in the molecule.

  The liquid crystal compound has a refractive index anisotropy, and has a function of imparting a desired retardation by being regularly arranged. As the liquid crystal compound, for example, a material exhibiting a liquid crystal phase such as a nematic phase and a smectic phase may be mentioned. It is preferable to use a material exhibiting liquid crystallinity. The liquid crystal compound exhibiting a nematic phase is preferably a material having spacers at both ends of a mesogen. Since the liquid crystal compound having the spacer at both ends of the mesogen has excellent flexibility, the transfer laminate for an optical film 1 can have excellent transparency.

  In the case where the above-mentioned alignment film 12 is formed of a vertical alignment film and the liquid crystal compound is homeotropically aligned, there is no particular limitation as long as it is a homeotropic liquid crystal material capable of forming homeotropic alignment. In addition, as the homeotropic liquid crystal material, without using a vertical alignment film, those that can form homeotropic alignment, and those that can form homeotropic alignment by using a vertical alignment film can be mentioned, In the present embodiment, either one can be suitably used.

  The liquid crystal compound is a polymerizable liquid crystal compound having a polymerizable functional group in a molecule as described above. By having a polymerizable functional group, it becomes possible to polymerize and fix the liquid crystal compound, so that the alignment stability is excellent and the change in retardation with time hardly occurs. Further, the polymerizable liquid crystal compound more preferably has a polymerizable functional group capable of three-dimensionally crosslinking in the molecule. By having a three-dimensionally crosslinkable polymerizable functional group, the sequence stability can be further enhanced. In addition, "three-dimensional crosslinking" means that liquid crystalline molecules are three-dimensionally polymerized with each other to form a network structure.

  Examples of the polymerizable functional group include those that polymerize by the action of ionizing radiation such as ultraviolet rays and electron beams, or heat. Examples of these polymerizable functional groups include a radical polymerizable functional group and a cationic polymerizable functional group. Representative examples of the radical polymerizable functional group include a functional group having at least one addition-polymerizable ethylenically unsaturated double bond, and include, for example, a vinyl group having or not having a substituent and an acrylate group (acryloyl). Group, a methacryloyl group, an acryloyloxy group, and a methacryloyloxy group). In addition, specific examples of the cationically polymerizable functional group include an epoxy group. In addition, examples of the polymerizable functional group include an isocyanate group and an unsaturated triple bond. Among them, a functional group having an ethylenically unsaturated double bond is preferably used from the viewpoint of the process.

  The amount of the polymerizable liquid crystal compound is not particularly limited as long as the viscosity of the retardation layer forming coating liquid (liquid crystal composition) can be adjusted to a desired value according to the coating method for coating the alignment film 12. Although not particularly limited, for example, the amount in the liquid crystal composition can be in the range of about 5 to 40 parts by mass. The polymerizable liquid crystal compounds can be used singly or as a mixture of two or more.

  The above-mentioned liquid crystal compound is usually dissolved in a solvent (diluting solvent). The solvent is not particularly limited as long as it can uniformly disperse the liquid crystal compound and the like. Examples thereof include hydrocarbon solvents such as benzene and hexane, and ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone (CHN). Solvents, ether solvents such as tetrahydrofuran, 1,2-dimethoxyethane, propylene glycol monoethyl ether (PGME), alkyl halide solvents such as chloroform and dichloromethane, methyl acetate, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate (PGMEA), amide solvents such as N, N-dimethylformamide, sulfoxide solvents such as dimethyl sulfoxide, anone solvents such as cyclohexane, methanol, ethanol, isopropyl It can be exemplified an alcohol solvent such as alcohol, but is not limited thereto. The solvent may be one kind or a mixed solvent of two or more kinds of solvents.

  The amount of the solvent is not particularly limited, and may be, for example, about 66 to 900 parts by mass with respect to 100 parts by mass of the liquid crystal compound. If the amount of the solvent is less than 66 parts by mass, the liquid crystal compound may not be dissolved uniformly, which is not preferable. On the other hand, when the amount exceeds 900 parts by mass, a part of the solvent remains, and there is a possibility that the reliability may decrease and a uniform coating may not be performed, which is not preferable.

  In addition, the liquid crystal composition may contain other compounds as necessary, as long as the arrangement order of the liquid crystal compound is not impaired. For example, a polymerization inhibitor, a plasticizer, a surfactant, and a silane coupling agent can be used.

  The thickness of the retardation layer 13 formed by applying the liquid crystal composition as described above on the alignment film 12 is not particularly limited. It is preferably about 2000 nm.

{2. About alignment film≫
As described above, in the transfer laminate for an optical film 1 according to the present embodiment, the alignment film 12 is made of an alignment film composition containing a surfactant containing fluorine at a predetermined ratio. I have. Specifically, it is composed of an alignment film composition containing a fluorine-containing surfactant in a ratio of 0.025% by mass or more and 0.1% by mass or less.

  In the transfer laminate 1 for an optical film having the alignment film 12 formed of the alignment film composition containing the fluorine-containing surfactant at a predetermined ratio, the interface between the support substrate 11 and the alignment film 12 is formed. , Fluorine will be present. The fluorine present at the interface between the support substrate 11 and the alignment film 12 is derived from fluorine contained in the surfactant in the alignment film composition. Here, fluorine derived from the surfactant bleeds out to the atmosphere side (compared to hydrophobic) more than the hydrophilic side of the support substrate 11. However, a small amount of fluorine, which could not bleed out to the atmosphere side, is more stable to migrate to the support base material 11 side than to exist in the alignment film 12. It is presumed that such fluorine will be present at the interface between the film and the alignment film 12.

  As described above, in the transfer laminate for optical films 1 in which fluorine is present at the interface between the support base material 11 and the alignment film 12, when the interface between the support base material 11 and the alignment film 12 is set as the peeling interface. The peel strength of the support base material 11, more specifically, the peel strength when the support base material 11 is peeled at a high speed can be reduced. Thereby, for example, even when the support base material 11 is peeled at a high speed in order to increase productivity, it is possible to effectively suppress the occurrence of transfer failure (separation of tears) of the transfer laminated body with respect to the transferred body. it can.

  For example, when the peeling speed is lower than about 30 m / min, the peeling strength is not changed as compared with the conventional transfer laminate, but when the peeling is performed at a higher speed, the alignment film 12 containing the fluorine-containing surfactant is removed. In the transfer laminate 1 for an optical film having the following, the peel strength can be effectively reduced. More specifically, for example, when the peeling speed is 50 m / min, the peel strength becomes 0.350 [N / 50 mm] or less.

  As will be described in detail in the following examples, when the transfer laminate of the sample of the comparative example (conventional) (without surfactant) is used, the peel strength at a peel speed of 50 m / min is about 0.425. [N / 50 mm], in the transfer laminate 1 for optical films (Example), the peel strength at the same peeling speed of 50 m / min was 0.350 [N / 50 mm] or less. It can be seen that the use of the transfer laminate 1 can greatly reduce the peel strength.

  This means that the higher the speed of separation, the more remarkably the effect of lowering the peel strength is exhibited. For example, even when the support base material 11 is separated at a high speed in order to increase the productivity, the transfer to the transfer target is not affected. The occurrence of transfer failure of the transfer laminate can be effectively suppressed.

  In addition, by including a surfactant containing fluorine in the alignment film composition as described above, it is possible to exhibit excellent uniform applicability (leveling property), and the formed alignment film 12 can be made smoother. Can be changed.

  The fluorine-containing surfactant contained in the alignment film 12 is not particularly limited as long as it is a surfactant containing fluorine, and may be any of cationic, anionic, amphoteric, and nonionic.

  For example, cationic fluorosurfactants include perfluoroalkyltrimethylammonium salts such as perfluoroalkyltrimethylammonium iodide. Examples of the anionic fluorine-based surfactant include perfluoroalkylsulfonic acid salts such as ammonium perfluoroalkylsulfonic acid, potassium perfluoroalkylsulfonic acid, and sodium perfluoroalkylsulfonic acid; Perfluoroalkylcarboxylates such as ammonium acid salts, potassium perfluoroalkylcarboxylates, sodium perfluoroalkylcarboxylates, perfluoroalkylnaphthalenesulfonates, perfluoroalkylbenzenesulfonates, perfluoroalkyldiallylsulfonates And perfluoroalkyl phosphates. In addition, examples of the amphoteric fluorine-based surfactant include perfluoroalkylaminosulfonic acid salts (perfluoroalkylbetaines). Examples of the nonionic fluorine-based surfactant include, for example, perfluoroalkylethylene oxide adducts, perfluoroalkyl esters, oligomers containing perfluoroalkyl groups / hydrophilic groups, oligomers containing perfluoroalkyl groups / lipophilic groups, Examples include perfluoroalkyl group-containing oligomers, perfluoroalkyl group / lipophilic group-containing urethanes, perfluoroalkyl oligomers, perfluoroalkylamine oxides, and perfluoroalkyl group-containing silicone ethylene oxide adducts.

  As described above, the content of the fluorine-containing surfactant is set to 0.025% by mass or more and 0.1% by mass or less. When the content is less than 0.025% by mass, the peel strength at the time of high-speed peeling cannot be effectively reduced, and transfer failure cannot be effectively suppressed.

  On the other hand, when the content exceeds 0.1% by mass, although an effect of weakening the peeling strength at the time of high-speed peeling is obtained, a large amount of fluorine is contained in the alignment film 12. When a coating liquid for forming a retardation layer containing a liquid crystal composition is applied to the liquid crystal composition, the coating liquid cannot be uniformly applied on the alignment film 12 and the alignment film 12 is exposed, so-called, Causes cissing. As a result, poor adhesion to the retardation layer 13 occurs, the phase difference in the portion where repelling has occurred is reduced, causing defects and the like, causing poor appearance, and further reducing the yield. Become.

{3. Method for producing transfer laminate for optical film≫
Next, a method for producing a transfer laminate for an optical film will be described. FIG. 2 is a flowchart showing the flow of the manufacturing process of the transfer laminate 1 for an optical film. In the following description of the manufacturing method, a case where the alignment film 12 is formed of a vertical alignment film will be described as an example, but the present invention is not limited to this.

  As shown in FIG. 2, in the production of the transfer laminate 1 for an optical film, first, a support substrate 11 made of a PET film is provided from a long film wound on a roll (S1).

  Next, in the alignment film forming step (S2), a coating liquid (alignment film composition) for a vertical alignment film is coated on the support substrate 11 drawn out from a roll, and thermally cured using a drier or the like. Perform processing. As a result, a vertical alignment film is formed on the support substrate 11, and the alignment film 12 is formed. At this time, in the present embodiment, an alignment film composition containing a surfactant containing fluorine at a ratio of 0.025% by mass or more and 0.1% by mass or less is coated on the support substrate 11. Thus, an alignment film 12 is formed.

  Next, in a retardation layer forming step (S3), a coating liquid of a liquid crystal composition containing a liquid crystal compound (coating liquid for forming a retardation layer) is coated on the alignment film 12. Thereafter, the resultant is dried and cured by irradiation with ultraviolet rays or the like, thereby forming the retardation layer (liquid crystal layer) 13. Note that a leveling process for making the thickness of the retardation layer 13 uniform may be performed prior to the ultraviolet irradiation process.

  Here, in the present embodiment, as described above, the alignment film composition containing the fluorine-containing surfactant at a ratio of 0.025% by mass or more and 0.1% by mass or less is provided on the support substrate 11. The orientation film 12 is formed by coating. In such an alignment film 12, fluorine derived from a surfactant is present at the interface between the support base material 11 and the alignment film 12. The peel strength at the time of doing can be weakened. Thereby, even when the support base material 11 is peeled off at a high speed in order to increase productivity, it is possible to effectively suppress occurrence of transfer failure of the transfer laminate to the transfer target.

  In this way, a laminated film in which the support substrate 11 / the alignment film 12 / the retardation layer 13 is laminated in this order is manufactured, and the obtained film is wound on a take-up reel or the like. A cutting process for cutting out to the size of is performed. Through such steps, the transfer laminate 1 for an optical film is manufactured.

  The method for coating the alignment film composition on the support substrate 11 and the method for coating the phase difference layer forming coating liquid on the alignment film 12 are not particularly limited. , Die coating method, gravure coating method, reverse coating method, knife coating method, dip coating method, spray coating method, air knife coating method, spin coating method, roll coating method, printing method, dipping and pulling method, curtain coating method, casting method , A bar coating method, an extrusion coating method, an E-type coating method and the like can be used.

≪4. Production method of optical film using transfer laminate for optical film≫
Next, a method for producing an optical film by a transfer method using the above-described transfer laminate for an optical film will be described. FIG. 3 shows the transfer of an optical film to an optical functional layer made of a reverse dispersion stretched film, which imparts a phase difference of 1/4 wavelength to transmitted light, using the transfer laminate for an optical film 1 according to the present embodiment. FIG. 3 is a diagram showing a flow of steps when an optical film is produced by transferring a transfer layer of a laminate 1. FIG. 3 is a diagram showing a cross section of the film, and is a diagram showing the flow of steps while showing the layer structure of the film in each step. Further, the layer structure of the film is not limited to this.

  First, as shown in FIG. 3A, an alignment film 12 made of, for example, a vertical alignment film is formed on a support base material 11 (a release substrate) made of a PET film. A retardation layer (liquid phase layer) 13 is formed by applying a coating liquid for forming a retardation layer containing a liquid crystal composition, and a transfer laminate 1 for an optical film is produced. Here, as described above, in the production of the transfer laminate 1 for an optical film, an alignment film composition containing a fluorine-containing surfactant in a ratio of 0.025% by mass or more and 0.1% by mass or less is used. Thus, the alignment film 12 is formed.

  Next, as shown in FIG. 3B, an adhesive layer 21 containing, for example, a UV adhesive or the like is formed on the retardation layer 13 of the manufactured transfer laminate 1 for an optical film. Then, a polymer film (protective film) 22 is formed, and the transfer laminate 1 for an optical film is transferred.

  As the adhesive layer 21, various kinds of adhesives such as an ultraviolet curable resin, a thermosetting resin, and a pressure-sensitive adhesive can be widely used. It is preferable to apply a curable resin to form a UV adhesive layer. In this case, an adhesive layer having a thickness of about 1 μm can be produced. Note that an adhesive layer may be applied to the adhesive layer 21.

  The polymer film is not particularly limited, and for example, a stretched film having reverse dispersion properties (hereinafter, also referred to as “reverse dispersion stretched film 22”) can be used. The reverse dispersion stretched film 22 is formed of, for example, a COP (cycloolefin polymer) film stretched uniaxially or obliquely in a desired direction, and has a slow axis with respect to an absorption axis of the linear polarizing plate. It is disposed so as to form an angle of θ2 degrees counterclockwise, and plays a role as a quarter-wave plate retardation layer that imparts a quarter-wave phase difference to transmitted light. By using such a reverse dispersion stretched film 22, for example, the configuration of the base material, the resin layer for a 波長 wavelength plate, and the alignment film for a 波長 wavelength plate can be omitted, and thus the entire optical film can be omitted. The layer thickness can be reduced.

  When a polymer film 22 such as a reverse dispersion stretched film is laminated on the transfer laminate for optical film 1 and transferred, as shown in FIG. 3C, the support base material of the transfer laminate for optical film 1 11 is peeled off. The transfer laminate 1 for an optical film functions as a release support in order to transfer the transfer layer (the retardation layer 13 and the alignment film 12) to another base material (such as a polymer film). The supporting base material 11 is peeled off. In addition, peeling of the support base material 11 may be performed after laminating a linear polarizing plate described later.

  Then, when the support base material 11 of the transfer laminate for optical film 1 is peeled off, next, as shown in FIG. 3D, a linear polarizing plate provided with an adhesive layer 31 is laminated.

  As a linear polarizing plate, an optical functional layer is disposed after the lower surface side of a base material 34 made of a transparent film such as TAC (triacetyl cellulose) is saponified. The base material 34 is made of poly (methyl meth) acrylate, poly (meth) butyl acrylate, methyl (meth) acrylate-butyl (meth) acrylate, methyl (meth) acrylate-styrene copolymer. Resin such as an acrylic resin such as coalescence, glass such as soda glass, potassium glass, lead glass, and quartz glass can also be applied.

  The optical function layer is a part that performs an optical function as a linear polarizing plate. For example, a layer in which a polarizer 33 and a transparent protective film (base material) 32 made of an acrylic resin or the like are sequentially laminated is used. Can be. Such a linear polarizing plate is bonded to a polymer film 22 such as a reverse dispersion stretched film via an adhesive layer 31.

  Based on the steps as described above, an optical film can be manufactured by a transfer method using the transfer laminate for an optical film 1. In particular, in the present embodiment, the fluorine-containing surfactant is contained in the alignment film 12 of the transfer laminate 1 for an optical film, so that the fluorine forms the support substrate 11 and the alignment film 12. Since it is present at the interface, the peel strength when the support base material 11 is peeled at a high speed can be reduced. As a result, it is possible to effectively suppress the occurrence of transfer failure of the transfer laminated body with respect to the transfer target body, and it is possible to increase productivity.

  As described above, it is assumed that the transfer laminate for an optical film 1 has the alignment film 12 composed of a vertical alignment film, and the transfer film for the optical film 1 is provided on the retardation layer 13 with the adhesive layer 21 interposed therebetween. By laminating the dispersion-stretched film 22 and providing a linear polarizer having a polarizer 33 sandwiched between substrates 32 and 34 made of a transparent film on the reverse dispersion-stretched film 22, simple and high productivity can be obtained. Thus, an optical film having a positive C plate due to the inverse dispersion characteristic can be obtained.

  Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to the following Examples.

<Examples and comparative examples>
[Example 1]
(Production of transfer laminate for optical film)
Using a 38 μm-thick PET base material that has not been subjected to an easy adhesion treatment such as a corona discharge treatment, a composition for a vertical alignment film is coated on one surface thereof to a thickness of 3 μm, and polarized ultraviolet light of 20 mJ / cm ² is applied. Irradiation produced an alignment film. Here, as the composition for the vertical alignment film, a fine cure PXV-18 manufactured by Sanyo Chemical Industries, Ltd. was used, and a fluorine-containing surfactant (MegaFac F-Made manufactured by DIC) was added to the composition. 554) at a rate of 0.025% by mass.

  Subsequently, a liquid crystal layer composition (manufactured by Merck Ltd., RMM28B) was applied by die coating on the formed alignment film to form a retardation layer (liquid crystal layer) having a thickness of about 1 μm. In this way, a transfer laminate for an optical film in which a substrate (support substrate), an alignment film, and a retardation layer were laminated in this order was produced.

(Transfer of transfer laminate for optical film)
Next, using the transfer laminate for optical films obtained as described above, transfer was performed using a reverse dispersion stretched film as a transfer target. Specifically, first, an adhesive layer containing a UV adhesive is formed on the retardation layer of the obtained transfer laminate for optical film, and a reverse dispersion stretched film made of a COP film is adhered on the adhesive layer. In addition, the transfer layer (retardation layer, alignment film) in the transfer laminate for an optical film was transferred. Then, after bonding the reverse dispersion stretched film, the PET substrate was peeled off using the interface between the PET substrate and the alignment film as a peeling interface.

  In this example, the peeling strength [N / 50 mm] when the PET substrate was peeled off was measured by changing the peeling speed in peeling the PET substrate.

(XPS analysis of alignment film side surface after PET substrate peeling)
In Example 1, the transfer layer was transferred to the reverse dispersion stretched film using the transfer laminate for an optical film, and elemental analysis was performed on the alignment film side surface of the transfer laminate after peeling off the PET substrate. The elemental analysis was performed by X-ray photoelectron spectroscopy (XPS) using an X-ray spectrometer ESCALAB 220i-XL manufactured by Thermo Fisher Scientific. Table 1 below shows the results of XPS analysis of the alignment film surface after peeling the PET substrate.

  As shown in the analysis results in Table 1, 0.3 at% of fluorine, which is a component contained in the surfactant, is present on the surface of the alignment film after peeling the PET substrate, that is, at the interface between the PET substrate and the alignment film. I knew I was doing it.

[Example 2]
Except that an orientation film was prepared using a composition containing a fluorine-containing surfactant (manufactured by DIC, Megafac F-554) in a proportion of 0.050% by mass as a composition for a vertical orientation film. A transfer laminate for an optical film was prepared in the same manner as in Example 1, and subsequently, a transfer treatment was performed using the reverse dispersion-stretched film as a transfer object. Also in the sample of Example 2, the peeling strength [N / 50 mm] when the PET substrate was peeled off while changing the peeling speed was measured.

[Example 3]
Except that a fluorine-containing surfactant (manufactured by DIC, Megafac F-554) was added at a ratio of 0.100% by mass as a composition for a vertical alignment film, an alignment film was prepared. A transfer laminate for an optical film was prepared in the same manner as in Example 1, and subsequently, a transfer treatment was performed using the reverse dispersion-stretched film as a transfer object. And also in the sample of Example 3, the peeling strength [N / 50 mm] when the PET substrate was peeled off while changing the peeling speed was measured.

[Comparative Example 1]
A transfer laminate for an optical film was prepared in the same manner as in Example 1 except that a fluorine-containing surfactant was not added as a composition for a vertical alignment film. Was performed. Also in the sample of Comparative Example 1, the peeling strength [N / 50 mm] when the PET substrate was peeled off while changing the peeling speed was measured.

<Result>
FIG. 4 shows the peel strength [N / N] when the PET base material was peeled off by changing the peeling rate for the optical film transfer laminates of Examples 1 to 3 and the optical film transfer laminate of Comparative Example 1. 50 mm] is a graph showing the result of measurement.

  As can be seen from the graph of FIG. 4, for example, when the peeling speed is lower than about 30 m / min, there is no difference in the peel strength between the respective transfer laminates, but when the peeling is performed at a higher speed, the fluorine-containing surfactant is used. It can be seen that the peel strength of the transfer laminates for optical films of Examples 1 to 3 having an alignment film containing

  Specifically, in the transfer laminate for optical film of Comparative Example 1 in which the fluorine-containing surfactant was not added, the peel strength when the PET substrate was peeled at a peel speed of 50 m / min was about 0.425 [N / 50 mm], on the other hand, in the transfer laminates for optical films of Examples 1 to 3 in which a predetermined amount of a fluorine-containing surfactant was added to form an alignment film, the separation was performed at a separation speed of 50 m / min. It can be seen that the strength is 0.350 [N / 50 mm] or less, which is effectively weakened.

  In addition, in the transfer laminates for optical films of Examples 1 to 3, it can be seen that the more the peeling speed is higher than 30 m / min, the more remarkably the effect of lowering the peel strength appears. For this reason, according to the transfer laminate for an optical film as in Examples 1 to 3, for example, even when the support base material is peeled off at a high speed in order to increase productivity, the transfer laminate to the transfer-receiving body can be obtained. It can be seen that the occurrence of poor transfer of the body can be effectively suppressed.

Reference Signs List 1 transfer laminate for optical film 11 support base material 12 alignment film 13 retardation layer (liquid crystal layer)

Claims (3)

A method for producing a transfer laminate for an optical film having a transfer layer,
A preparation step of preparing a support base material made of polyethylene terephthalate that has not been subjected to an easy adhesion treatment on its surface,
Directly coating and curing an alignment film composition containing a fluorine-containing surfactant in an amount of 0.025% by mass or more and 0.1% by mass or less on the surface of the support substrate that has not been subjected to the easy adhesion treatment. Forming an alignment film by forming an alignment film,
A phase difference layer forming step of forming a phase difference layer by coating and curing a liquid crystal composition containing a liquid crystal compound on the alignment film,
A method for producing a transfer laminate for an optical film, wherein fluorine is present at an interface between the alignment film formed in the alignment film forming step and the support substrate. A method for producing an optical film, comprising:
A film laminating step of laminating a reverse dispersion stretched film via an adhesive layer on the retardation layer of the optical film transfer laminate manufactured by the method for producing an optical film transfer laminate according to claim 1,
After the film laminating step, a polarizing plate laminating step of laminating a linear polarizing plate on the reverse dispersion stretched film via an adhesive layer,
After the film laminating step, a transfer step of peeling the support base material from the alignment film and transferring a transfer layer to the reverse dispersion stretched film. A transfer laminate for an optical film having a transfer layer,
A support base material made of polyethylene terephthalate that has not been subjected to an easy adhesion treatment on its surface, an alignment film, and a retardation layer are directly laminated in this order,
The alignment film is made of a cured product of an alignment film composition containing a surfactant containing fluorine,
At the interface between the support substrate and the alignment film, fluorine is present,
A transfer laminate for an optical film, wherein a peel strength when the support base material is peeled from an interface with the alignment film at a peel speed of 50 m / min is 0.35 N / 50 mm or less.

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