JP6394009B2 - Transfer laminate for optical film - Google Patents

Description

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

  In recent years, an optical film applied to a flat panel display or the like has been provided that ensures a desired optical characteristic by imparting a desired retardation to transmitted light by a retardation layer (see, for example, Patent Document 1). . In this type of optical film, an alignment film is prepared on the surface of a substrate made of a transparent film or the like, and cured in a state where the liquid crystal material is aligned by the alignment regulating force of the alignment film, thereby forming a retardation layer. A liquid crystal material applied to such a retardation layer usually has a positive wavelength dispersion characteristic, but recently, a liquid crystal material having a reverse dispersion characteristic has been proposed (see, for example, Patent Documents 2 and 3). . Here, the reverse dispersion characteristic is a wavelength dispersion characteristic in which the phase difference in the transmitted light is smaller toward the shorter wavelength side, and more specifically, retardation at a wavelength of 450 nm (R450) and retardation at a wavelength of 550 nm (R550). The relationship is R450 <R550.

  In addition, in the image display panel, a method for improving various optical characteristics such as viewing angle characteristics and color using an A plate, a C plate, etc. has been proposed. A device for optical compensation of an IPS liquid crystal display device using a C plate has been proposed. Here, the optical compensation is a configuration that reduces light leakage in an oblique direction from the 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 indexes in the in-plane direction, and nz is a refractive index in the thickness direction.

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

  Now, such an optical film is produced by, for example, a transfer method using a transfer laminate for an optical film having a transfer layer transferred to an optical functional layer such as a linearly polarizing plate that functions as a linearly polarizing plate. The In the transfer method, 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 once a releasable support (support After the layer is formed in a peelable manner on the body substrate), a transfer laminate is produced, and then the layer formed on the support is finally laminated according to the process, demand, etc. In this method, a desired layer is formed on a predetermined base material by bonding and laminating on the (transfer base material) 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. In addition, the optical film produced by the transfer method is described in patent document 5 and patent document 6, for example.

  However, when the optical film is produced by transfer as described above, when the transfer laminate is transferred onto the transfer target, the transfer laminate is not separated at the end of the portion to be transferred, and is transferred onto the transfer target. There may be a so-called crying (transfer defect) in which an excess portion of the transfer laminate remains on the side of the laminate.

JP-A-10-68816 U.S. Pat. No. 8,119,026 Japanese translation of PCT publication No. 2010-52892 JP-T 2006-520008 JP 2005-49865 A JP 2007-156234 A

  The present invention has been proposed in view of such circumstances, and suppresses a peeling failure of a support substrate when an optical film is produced using a transfer laminate for an optical film having a transfer layer. An object of the present invention is to provide a transfer laminate for an optical film capable of preventing the transfer failure of the transfer layer with respect to the transfer target.

This inventor repeated earnest examination in order to solve the subject mentioned above. As a result, in the transfer laminate for optical films, the infrared absorption peak at wave number 810 cm ⁻¹ is P1 and the infrared absorption peak at wave number 1730 cm ⁻¹ is measured by total reflection measurement for the alignment film laminated on the support substrate. It has been found that by forming so that the ratio P1 / P2 when P2 is equal to or greater than a predetermined value, it is possible to suppress the peeling failure of the support substrate and to effectively suppress the occurrence of transfer failure of the transfer laminate. It was. That is, the present invention provides the following.

(1) The present invention provides a transfer laminate for an optical film having a transfer layer, wherein a support substrate made of polyethylene terephthalate that has not been subjected to an easy adhesion treatment on the surface, an alignment film, and a retardation layer. When the infrared absorption peak at a wave number of 810 cm ⁻¹ by the total reflection measurement method is P1, and the infrared absorption peak at a wave number of 1730 cm ⁻¹ at the interface between the alignment film and the support substrate is P1, and the infrared absorption peak at a wave number of 1730 cm ⁻¹ is P2. Is a transfer laminate for optical films, wherein the ratio P1 / P2 is 0.15 or more.

  (2) Moreover, this invention is the invention of (1), The thickness of the said alignment film is 3 micrometers or more, and peeling strength when peeling the said support body base material with the peeling speed of 300 mm / min is 180 mN / 50 mm or less. It is a transfer laminated body for optical films characterized by being.

  (3) The present invention is the transfer laminate for an optical film according to the invention (1) or (2), wherein the alignment film is composed of a vertical alignment film.

  (4) Further, in the invention according to any one of (1) to (3), the transfer layer is transferred to an optical functional layer that imparts a phase difference corresponding to a quarter wavelength composed of a reverse dispersion stretched film. A transfer laminate for optical films.

  According to the transfer laminate for an optical film of the present invention, it is possible to suppress the peeling failure of the support substrate and effectively prevent the transfer laminate from being transferred to the transfer target.

It is a cross-sectional schematic diagram which shows an example of the transfer laminated body for optical films. The graph showing the relationship between the ratio “P1 / P2” of the infrared absorption peak P1 near the wave number of 810 cm ^{−1 and} the infrared absorption peak P2 near the wave number of 1730 cm ⁻¹ by the total reflection measurement method with respect to the film thickness [μm] of the alignment film. It is. Measurement of peel strength [mN / 50 mm] (peel strength when peeled at a peel rate of 300 mm / min) of the support substrate with respect to the film thickness [μm] of the alignment film corresponding to the curing reaction rate shown in FIG. It is a graph which shows a result. It is a flowchart which shows the flow of the production process of the transfer laminated body for optical films. It is a figure for demonstrating the flow which produces an optical film by the transfer method using the transfer laminated body for optical films.

Hereinafter, specific embodiments of the transfer laminate for optical films according to the present invention (hereinafter referred to as “this embodiment”) will be described in detail in the following order. In addition, this invention is not limited to the following embodiment, A various change is possible in the range which does not change the summary of this invention.
1. 1. Configuration of optical film transfer laminate 2. Alignment film 3. Method for producing transfer laminate for optical film Method for producing optical film using transfer laminate for optical film

<< 1. Configuration of transfer laminate for optical film >>
FIG. 1 is a cross-sectional view schematically showing an example of a transfer laminate 1 for an optical film according to the present embodiment. As shown in FIG. 1, a transfer laminate 1 for an optical film has a support substrate 11 made of polyethylene terephthalate (PET), an alignment film 12, and a retardation layer (liquid crystal layer) 13 laminated in this order. It will be.

  The optical film transfer laminate 1 is transferred to, for example, an optical functional layer of a linearly polarizing plate, an optical functional layer that imparts a phase difference corresponding to a quarter wavelength to transmitted light, and the like. 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 this optical film transfer laminate 1, for example, a polymer film such as a reverse dispersion stretched film is bonded onto the retardation layer 13 via an adhesive to transfer the transfer layer, and a linear polarizing plate is further bonded. By combining them, a predetermined optical film can be produced. At this time, in the production of the optical film, only the support substrate 11 having releasability is peeled after the transfer layer is transferred to the substrate such as a reverse dispersion stretched film on the optical film transfer laminate 1. .

In the transfer laminate 1 for an optical film according to the present embodiment, the alignment film 12 laminated on the support substrate 11 is measured by the total reflection measurement method at the interface between the alignment film 12 and the support substrate 11. the infrared absorption peak at around a wave number 810 cm ^-1 P1, the ratio at which the infrared absorption peak at around a wave number 1730 cm ^-1 by P2 'P1 / P2 "is characterized by at least 0.15.

Here, when the infrared spectrum is measured by the total reflection measurement method at the interface between the alignment film 12 and the support substrate 11, the infrared absorption peak (P1) in the vicinity of the wave number of 810 cm ⁻¹ disappears due to the reaction caused by the ultraviolet irradiation. -The peak of a carbon double bond (C = C) is shown. In addition, the infrared absorption peak (P2) in the vicinity of a wave number of 1730 cm ⁻¹ indicates an ester bond peak that does not disappear due to a reaction by ultraviolet irradiation. Therefore, the ratio “P1 / P2” at these peaks P1 and P2 can be expressed as the curing reaction rate of the alignment film, that is, the degree of curing in the alignment film.

  And in the transfer laminated body 1 for optical films, the ratio "P1 / P2" of P1 and P2 is 0.15 or more. According to such a transfer laminated body 1 for optical films, the support substrate 11 The peel strength can be weakened. Thereby, the peeling defect of the support base material 11 can be effectively suppressed, and the occurrence of the transfer defect of the transfer laminate with respect to the transfer target can be prevented.

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

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

  Although it does not specifically limit as thickness of the support base material 11, For example, it is preferable to set it as the range of 20 micrometers-200 micrometers. If the thickness of the support substrate 11 is less than 20 μm, it may not be possible to provide the minimum necessary self-supporting property as a transfer laminate for an optical film. On the other hand, when the thickness exceeds 200 μm, when the optical film transfer laminate is long, the long optical film transfer laminate is cut to obtain a single wafer optical film transfer laminate. In this case, it is not preferable because processing waste increases and wear of the cutting blade is accelerated.

<1-2. Alignment film>
The alignment film 12 is obtained by coating and curing the alignment film composition (alignment film composition) on the support substrate 11 described above, and exhibits an alignment regulating force. Here, the alignment regulating force is a function of arranging (orienting) the liquid crystal compound in a predetermined direction when a layer (retardation layer 13) made of a polymerizable liquid crystal compound (liquid crystal material) is formed on the alignment film 12. Say.

  The alignment film 12 is made of a material containing an ultraviolet curable resin as a main raw material. In addition, the alignment film 12 is not particularly limited, but can be constituted by, for example, a vertical alignment film that homeotropically aligns the molecular axes of the liquid crystal compound molecules in the retardation layer 13 (vertical alignment).

  The ultraviolet curable resin constituting the alignment film 12 is not particularly limited as long as it can be cured by irradiation with ultraviolet rays. For example, monomers such as acrylates and methacrylates, prepolymers, or these A mixture obtained by adding a photopolymerization initiator such as acetophenone, benzophenone, aromatic iodonium to the mixture can be used. More specifically, commonly used resins such as pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, dipentaerythritol polyfunctional methacrylate, or the like can be used. What mixed the polymerization initiator can be used.

  The solvent (dilution solvent) used in the alignment film composition is not particularly limited as long as it can dissolve the alignment material at 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, propylene glycol monoethyl ether (PGME), alkyl halide solvents such as chloroform and dichloromethane, methyl acetate Ester solvents such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate (PGMEA), amide solvents such as N, N-dimethylformamide, sulfoxide solvents such as dimethyl sulfoxide, anan solvents such as cyclohexane, Methanol, ethanol can be exemplified an alcohol solvent such as isopropyl alcohol. Moreover, one type of solvent may be sufficient and the mixed solvent of two or more types of solvents may be sufficient.

  Such an alignment film 12 composed of a vertical alignment film or the like is applied by applying a coating solution made of an alignment film composition containing the above-described material to the support substrate 11, dried, and cured by irradiation with ultraviolet rays. To make it. The alignment film 12 is composed of the cured product thus produced.

Here, in the transfer laminate 1 for an optical film according to the present embodiment, the alignment film 12 has a wave number of 810 cm ⁻¹ by a total reflection measurement method at the interface between the alignment film 12 and the support substrate 11. The ratio “P1 / P2” is 0.15 or more when the infrared absorption peak is P1 and the infrared absorption peak at a wave number of 1730 cm ⁻¹ is P2. As will be described in detail later, according to the transfer laminate 1 for an optical film having such an alignment film 12, the peel strength of the support substrate 11 can be weakened. 11 can be effectively suppressed, and transfer defects of the transfer laminate with respect to the transfer target can be prevented.

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

  The liquid crystal compound has refractive index anisotropy and has a function of imparting a desired retardation by regularly arranging the liquid crystal compound. Examples of the liquid crystal compound include materials exhibiting a liquid crystal phase such as a nematic phase and a smectic phase, but the nematic phase is easier in order to arrange regularly than liquid crystal compounds exhibiting other liquid crystal phases. It is preferable to use a material exhibiting the above liquid crystallinity. The liquid crystal compound exhibiting a nematic phase is preferably a material having spacers at both ends of the mesogen. Since the liquid crystal compound having spacers at both ends of the mesogen is excellent in flexibility, the retardation film 1 can be excellent in transparency.

  In addition, when the alignment film 12 described above is made 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. Examples of the homeotropic liquid crystal material include materials that can form homeotropic alignment without using a vertical alignment film, and materials that can form homeotropic alignment by using a vertical alignment film. In the present embodiment, either can be suitably used.

  The liquid crystal compound is a polymerizable liquid crystal compound having a polymerizable functional group in the molecule as described above. By having a polymerizable functional group, it is possible to polymerize and fix the liquid crystal compound, so that the alignment stability is excellent and the phase change is less likely to occur over time. The polymerizable liquid crystal compound more preferably has a polymerizable functional group capable of three-dimensional crosslinking in the molecule. By having a polymerizable functional group capable of three-dimensional crosslinking, the sequence stability can be further enhanced. Note that “three-dimensional crosslinking” means that liquid crystal molecules are polymerized three-dimensionally 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 radical polymerizable functional groups and cationic polymerizable functional groups. Representative examples of radically polymerizable functional groups include functional groups having at least one addition-polymerizable ethylenically unsaturated double bond, such as vinyl groups having or without substituents, acrylate groups (acryloyl). Group, methacryloyl group, acryloyloxy group, generic name including methacryloyloxy group) and the like. Moreover, an epoxy group etc. are mentioned as a specific example of a cationically polymerizable functional 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 applied on the alignment film 12. Although it does not specifically limit, For example, it can be in the range of about 5-40 mass parts as a quantity in a liquid-crystal composition. In addition, a polymeric liquid crystal compound can be used individually by 1 type or in mixture of 2 or more types.

  The liquid crystal compound described above is usually dissolved in a solvent (dilution solvent). The solvent is not particularly limited as long as it can uniformly disperse liquid crystal compounds and the like. For example, hydrocarbon solvents such as benzene and hexane, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone (CHN). Solvent, ether solvents such as tetrahydrofuran, 1,2-dimethoxyethane, propylene glycol monoethyl ether (PGME), halogenated alkyl solvents such as chloroform and dichloromethane, methyl acetate, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate Ester solvents such as (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. Further, 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 can 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, which may reduce reliability and may not be uniformly applied.

  In addition, the liquid crystal composition may contain other compounds as necessary, as long as the alignment order of the liquid crystal compounds described above is not impaired. Examples thereof include a polymerization inhibitor, a plasticizer, a surfactant, and a silane coupling agent.

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

≪2. About alignment film >>
As described above, in the transfer laminate 1 for an optical film according to the present embodiment, the alignment film 12 has a wave number of 810 cm ⁻ according to the total reflection measurement method at the interface between the alignment film 12 and the support substrate 11. the infrared absorption peak at around ¹ P1, the ratio at which the infrared absorption peak at around a wave number 1730 cm ^-1 by P2 'P1 / P2 "is characterized in that it is formed to be 0.15 or more .

When an infrared spectrum is measured at the interface between the alignment film 12 and the support substrate 11, the infrared absorption peak (P1) near the wave number of 810 cm ⁻¹ is a carbon-carbon double bond (C═C) that disappears by a reaction caused by ultraviolet irradiation. ) Peak. In addition, the infrared absorption peak (P2) in the vicinity of a wave number of 1730 cm ⁻¹ indicates an ester bond peak that does not disappear due to a reaction by ultraviolet irradiation.

  Therefore, the ratio “P1 / P2” by these peaks P1 and P2 corresponds to the curing reaction rate of the alignment film, that is, the degree of curing in the alignment film. Specifically, the smaller the value of the ratio “P1 / P2” is, the higher the curing reaction rate at the interface between the alignment film 12 and the support substrate 11 is, and the greater the degree of curing (the curing is progressing), On the other hand, the larger the value of the ratio “P1 / P2”, the lower the curing reaction rate at the interface between the alignment film 12 and the support substrate 11 and the smaller the degree of curing (there is an uncured state where curing has not progressed). Show)

  Here, FIG. 2 is a graph showing the relationship with the ratio “P1 / P2” of the above-described peaks P1 and P2 with respect to the film thickness [μm] of the alignment film. That is, it is a graph about the film thickness (alignment film thickness) dependence of the curing reaction rate in the alignment film. In addition, the relationship shown in the graph of FIG. 2 is that total reflection is performed using an infrared spectroscopic device (manufactured by JASCO Corporation, FT-IR (610)) with respect to the interface between the alignment film and the support substrate. This is based on the result of IR measurement by the measurement method (ATR method).

  As shown in FIG. 2, as the alignment film becomes thicker, the ratio “P1 / P2” corresponding to the curing reaction rate at the interface between the alignment film and the support substrate increases. I understand. In other words, it can be seen that as the thickness of the alignment film increases, curing does not proceed and an uncured state is included at the interface between the alignment film and the support substrate.

  And in the transfer laminated body 1 for optical films which concerns on this Embodiment, ratio "P1 / P2" of the P1 and P2 is 0.15 or more. As described above, in the transfer laminate 1 for an optical film, the curing reaction rate of the alignment film 12 represented by the ratio “P1 / P2” at the interface between the alignment film and the support substrate 11 is 0.15 or more. Thus, it is considered that an uncured state is included in the interface. As a result, the adhesion between the alignment film 12 and the support substrate 11 is lowered, and the peel strength of the support substrate 11 can be effectively weakened. And thereby, the peeling defect of the support base material 11 can be suppressed effectively, and the transfer defect of the transfer laminated body with respect to a to-be-transferred body can be prevented.

  Specifically, in FIG. 3, the peel strength [mN / 50 mm] of the support substrate 11 with respect to the film thickness [μm] of the alignment film corresponding to the curing reaction rate shown in FIG. 2 (peeling at a peeling speed of 300 mm / min). The measurement results for the peel strength at the time of measurement are shown. In addition, the result shown in FIG. 3 is a result when the peel strength of the support substrate is measured using a sample having a width of 50 mm and using Tensilon (RTG-1310) manufactured by A & D Corporation.

  As shown in the results of FIG. 3, the peel strength of the support substrate increases as the thickness of the alignment film increases, that is, as the value of the curing reaction rate at the interface between the alignment film and the support substrate increases. It can clearly be seen that it is effectively weakened. More specifically, for example, when the value of the above-mentioned ratio “P1 / P2” is about 0.2 or more and the film thickness of the alignment film is 3 μm or more (see FIG. 2), the support substrate is peeled off at a speed of 300 mm. The peel strength when peeled at / min is 180 mN / 50 mm or less.

≪3. Manufacturing method of transfer laminate for optical film >>
Next, the manufacturing method of the transfer laminated body for optical films is demonstrated. FIG. 4 is a flowchart showing the flow of the manufacturing process of the optical film transfer laminate 1. In the following description of the manufacturing method, the 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 thereto.

  As shown in FIG. 4, in the production of the optical film transfer laminate 1, first, a support substrate 11 made of a PET film is provided from a long film wound around a roll (S1).

  Next, in the alignment film forming step (S2), a coating liquid (alignment film composition) for the vertical alignment film is applied onto the support substrate 11 drawn out from the roll and cured by ultraviolet irradiation. As a result, a vertical alignment film is produced on the support substrate 11 and the alignment film 12 is formed.

At this time, in the present embodiment, the infrared absorption peak of wave number 810 cm ⁻¹ by the total reflection measurement method at the interface between the alignment film 12 and the support substrate 11 is P1, and the infrared absorption peak of wave number 1730 cm ⁻¹ is P2. The coating liquid is applied onto the support substrate 11 so that the ratio P1 / P2 is 0.15 or more, and the alignment film 12 is formed.

  Next, in the retardation layer forming step (S3), a liquid crystal composition coating liquid containing a liquid crystal compound (a retardation layer forming coating liquid) is applied onto the alignment film 12. Thereafter, the retardation layer (liquid crystal layer) 13 is formed by drying and curing by irradiation with ultraviolet rays or the like. In addition, you may make it perform the leveling process for making the layer thickness of the phase difference layer 13 uniform before an ultraviolet irradiation process.

Here, in the present embodiment, as described above, the infrared absorption peak at the wave number of 810 cm ⁻¹ at the interface between the alignment film 12 and the support substrate 11 is P1, and the infrared absorption peak at the wave number of 1730 cm ^−1. The alignment film 12 is formed so that the curing reaction rate represented by the ratio P1 / P2 with respect to P2 is 0.15 or more. In such an alignment film 12, the peel strength at the interface between the support substrate 11 and the alignment film 12 can be effectively reduced. Thereby, the peeling defect of the support base material 11 can be suppressed effectively, and the transfer defect of the transfer laminated body with respect to a to-be-transferred body can be prevented.

  Thus, after manufacturing the laminated body film by which the support base material 11 / alignment film 12 / retardation layer 13 are laminated | stacked in this order, after winding up the obtained film with a winding reel etc., desired The cutting process is performed to cut out to the size. Through such steps, the optical film transfer laminate 1 is produced.

  The coating method of the alignment film composition on the support substrate 11 and the coating method of the retardation layer forming coating liquid on the alignment film 12 are not particularly limited. For example, , 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 lifting method, curtain coating method, casting method , Bar coating method, extrusion coating method, 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 the transfer method using the above-described optical film transfer laminate will be described. FIG. 5 shows the optical film transfer laminate 1 for an optical film according to the present embodiment. The optical film transfer is applied to an optical functional layer made of a reverse dispersion stretched film and imparts a phase difference of ¼ wavelength to transmitted light. It is a figure which shows the flow of the process at the time of transferring the transfer layer of the laminated body 1, and producing an optical film. In addition, this FIG. 5 is a figure which shows the cross section of a film, and is a figure which shows the flow of a process, showing the layer structure of the film in each process. Further, the layer structure of the film is not limited to this.

First, as shown in FIG. 5A, an alignment film 12 made of, for example, a vertical alignment film is formed on a support base material 11 (release base material) made of a PET film, and the alignment film 12 is formed on the alignment film 12. A phase difference layer (liquid phase layer) 13 is formed by applying a phase difference layer forming coating solution containing a liquid crystal composition to produce a transfer laminate 1 for an optical film. Here, as described above, in the production of the transfer laminate 1 for an optical film, the infrared absorption peak at a wave number of 810 cm ⁻¹ by the total reflection measurement method at the interface between the alignment film 12 and the support substrate 11 is P1. The alignment film 12 is configured so that the ratio P1 / P2 is 0.15 or more when the infrared absorption peak at a wave number of 1730 cm ⁻¹ is P2.

  Next, as shown in FIG. 5 (b), an adhesive layer 21 containing, for example, a UV adhesive is formed on the retardation layer 13 of the produced optical film transfer laminate 1. Then, a polymer film (protective film) 22 is formed, and the optical film transfer laminate 1 is transferred.

  Various adhesives such as an ultraviolet curable resin, a thermosetting resin, and a pressure sensitive adhesive can be widely applied as the adhesive layer 21. Among them, ultraviolet (UV) is used from the viewpoint of reducing the overall thickness. 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. 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 characteristics (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 that is stretched in one axial direction or obliquely stretched in a desired direction, and the slow axis is relative to the absorption axis of the linearly polarizing plate. Thus, it is arranged to form an angle of θ2 degrees counterclockwise, and plays a role as a retardation layer for a quarter wavelength plate that imparts a phase difference of a quarter wavelength 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 quarter wavelength plate, and the alignment film for a quarter wavelength plate can be omitted. The layer thickness can be reduced.

  When the polymer film 22 such as reverse dispersion stretched film is laminated and transferred to the optical film transfer laminate 1, next, as shown in FIG. 5 (c), the support substrate of the optical film transfer laminate 1. 11 is peeled off. The optical film transfer laminate 1 thus serves as a releasable support in order to transfer the transfer layer (retardation layer 13 and alignment film 12) to another substrate (polymer film or the like) in this way. The supporting substrate 11 to be carried is peeled off. In addition, you may make it perform peeling of the support body base material 11 after laminating | stacking the linear polarizing plate mentioned later.

  And if the support base material 11 of the transfer laminated body 1 for optical films is peeled, next, as shown in FIG.5 (d), the linearly-polarizing plate provided with the adhesive layer 31 will be laminated | stacked.

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

  The optical functional layer is a part responsible for the optical function as a linear polarizing plate, and 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 are used. Can do. Such a linearly polarizing plate is bonded to a polymer film 22 such as a reverse dispersion stretched film via an adhesive layer 31.

  Based on the above processes, an optical film can be produced by a transfer method using the optical film transfer laminate 1. In particular, in the present embodiment, the alignment film 12 of the optical film transfer laminate 1 is configured by controlling, for example, the film thickness as described above. 11 can effectively weaken the peel strength at the interface. Thereby, the peeling defect of the support base material 11 can be effectively suppressed, the transfer defect of the transfer laminate with respect to the transfer object can be prevented, and the productivity can be increased.

  As described above, the optical film transfer laminate 1 has the alignment film 12 made of a vertical alignment film, and is reversely disposed on the retardation layer 13 of the optical film transfer laminate 1 via the adhesive layer 21. A dispersion-stretched film 22 is laminated, and a linearly polarizing plate provided with a polarizer 33 sandwiched between base materials 32, 34 made of a transparent film is provided on the reverse dispersion-stretched film 22, so that high productivity can be achieved easily. Therefore, an optical film having a positive C plate with reverse dispersion characteristics can be obtained.

DESCRIPTION OF SYMBOLS 1 Transfer laminated body for optical films 11 Support base material 12 Alignment film 13 Retardation layer (liquid crystal layer)

Claims (4)

A transfer laminate for an optical film having a transfer layer,
A support substrate made of polyethylene terephthalate that has not been subjected to easy adhesion treatment on the surface, an alignment film, and a retardation layer are laminated in this order,
The alignment film is at least one cured product selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate,
The ratio P1 / P2 is 0 when the infrared absorption peak at a wave number of 810 cm ⁻¹ by the total reflection measurement method at the interface between the alignment film and the support substrate is P1, and the infrared absorption peak at a wave number of 1730 cm ⁻¹ is P2. A transfer laminate for an optical film, wherein the transfer laminate is from 15 to 0.27 . The alignment film has a thickness of 3 μm or more;
The transfer laminate for an optical film according to claim 1, wherein a peel strength when the support substrate is peeled at a peeling speed of 300 mm / min is 180 mN / 50 mm or less.   The transfer laminate for an optical film according to claim 1, wherein the alignment film is composed of a vertical alignment film. 4. The optical film according to claim 1, wherein the transfer layer is transferred to an optical functional layer made of a reverse dispersion stretched film and imparting a phase difference corresponding to ¼ wavelength. 5. Transfer laminate.

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