JP2010015045A - Elliptically polarizing plate roll and method of manufacturing the same, and liquid crystal substrate roll and display apparatus having elliptically polarizing plate - Google Patents

Abstract

The present invention provides an elliptically polarizing plate roll having a good display quality, a simple manufacturing process, a good yield, and a very thin shape, a manufacturing method thereof, a liquid crystal substrate roll using the same, and a display device.
SOLUTION: Polarizing films 101a and 101b, transparent protective films 102a and 102b laminated on one surface via first adhesive layers 104a and 104b, and a second adhesive on the other surface The first retardation plates 103a and 108b laminated via the layers 105a and 105b, and the second retardation plates 108a and 103b laminated thereon, one of the retardation plates is an obliquely stretched film, The other is composed of alignment films 106a and 106b formed by application of a composition containing a low-molecular photoalignment compound and light irradiation, and optically anisotropic layers 107a and 107b which are polymerized layers of liquid crystal compounds. These retardation plates are an elliptically polarizing plate roll having a slow axis in a direction intersecting with the slow axis of the first retardation plate, a method for manufacturing the same, a liquid crystal substrate roll, and a display device.
[Selection] Figure 1

Description

  The present invention relates to a roll-shaped elliptically polarizing plate (hereinafter referred to as an elliptically polarizing plate roll) and a method for producing the same, and more specifically, an elliptically polarizing plate including a broadband λ / 4 plate laminated on one surface of a polarizing film. It is related with a board roll and its manufacturing method. The present invention also relates to a liquid crystal substrate roll with an elliptically polarizing plate using the elliptically polarizing plate roll and a display device.

  An elliptically polarizing plate generally has a configuration in which a polarizing film (linear polarizer) is combined with an optical film having optical anisotropy or a liquid crystal compound layer, and is indispensable for a display device such as a liquid crystal display device. It is a member. For example, a retardation film such as a stretched film imparted with a retardation so as to optically compensate for a retardation imparted when passing through a liquid crystal, or a liquid crystalline compound layer obtained by aligning and curing on an alignment film or the like. By using an elliptically polarizing plate in which a plate is combined with a polarizing film, problems such as coloring and a decrease in contrast when the liquid crystal display device is viewed from an oblique direction can be solved.

  Conventionally, in a reflective liquid crystal mode liquid crystal display device or an organic EL display device that uses external light as a light source, in order to prevent the background light from being reflected and the background scene from being reflected, A circularly polarizing plate is used in which a stretched film having a retardation of ¼ wavelength or a transparent film (so-called λ / 4 plate) coated with a liquid crystal compound layer is combined with a polarizing film. Arrangement has been performed on both sides of the cell or on the viewing surface of the organic EL display device. However, since such a conventional λ / 4 plate has wavelength dependence, it has a phase difference of ¼ wavelength only for a specific wavelength, and ¼ wavelength over the entire visible light range. It does not have a phase difference. For this reason, when a circularly polarizing plate in which the conventional λ / 4 plate is combined with a polarizing film is used, there is a problem that a beautiful display cannot be obtained. In addition, such a circularly polarizing plate is a specific form of the elliptically polarizing plate in a broad sense, and in this specification, the “elliptical polarizing plate” includes a circularly polarizing plate.

  In order to solve the above problem, a stretched film having a phase difference of ½ wavelength with respect to the wavelength of light or a transparent film coated with a liquid crystal compound layer (so-called λ / 2 plate) and the above λ / 4 plate It is widely known to use a so-called broadband λ / 4 plate in which these optical axes are bonded so as to form a predetermined angle (see Patent Document 1).

  Here, in order to produce an elliptically polarizing plate using a broadband λ / 4 plate made of a stretched film, a polarizing film and two stretched films are bonded so that their optical axes form a predetermined angle. However, the direction of the optical axis of the stretched film subjected to a general stretching process is parallel or orthogonal to the width direction. Therefore, in order to bond each film so that these optical axes form a predetermined angle, it is necessary to cut each film into sheets and to bond each film one by one. There was a problem of becoming complicated. In addition, since such a single-wafer elliptical polarizing plate needs to be produced using a pressure-sensitive adhesive having a certain thickness, the thickness of the entire elliptical polarizing plate increases, and the light weight and thinness of displays in recent years. It was unsuitable for the market demands of chemicalization.

  From the viewpoints described above, in the production of elliptically polarizing plates, it is possible to reduce the weight and thickness, and simplify the production process, for example, efficient continuous production such as roll-to-roll bonding. There is a demand for a shift to manufacturing methods that can be used.

  For example, Patent Document 2 discloses a single-piece body obtained by cutting one of a long film of a retardation film and a polarizing film and the other film at a predetermined angle θ with respect to the optical axis. Discloses a method of manufacturing an elliptically polarizing plate by continuously bonding so as to form a predetermined angle θ. However, the elliptically polarizing plate obtained by this method is a laminate having a seam between sheets. An elliptically polarizing plate sheet continuously punched at an arbitrary size from an elliptically polarizing plate having such a seam defect similarly includes a seam defect, resulting in a problem that the yield decreases.

  Further, Patent Document 3 discloses a long transparent support, an optically anisotropic layer containing a liquid crystalline compound corresponding to a λ / 2 plate laminated on the transparent support, and the optical anisotropy. A broadband λ / 4 plate comprising a birefringent film made of a stretched film corresponding to a λ / 4 plate and a circularly polarizing plate in which the broadband λ / 4 plate and a polarizing film are combined is disclosed. ing. When an optically anisotropic layer containing a liquid crystal compound is applied as the λ / 2 plate constituting the broadband λ / 4 plate, the λ / 2 plate can be made to have a thickness of about several μm. The optical axis of the optically anisotropic layer can be set in any direction by controlling the alignment direction of the alignment film, and the adjustment of the optical axis is relatively easy. Is possible. However, laminating a birefringent film, which is a λ / 4 plate, is performed by cutting the stretched film into single sheets and optically different so that the optical axis forms a predetermined angle with respect to the optical axis of the optically anisotropic layer. Since a process of bonding onto the isotropic layer is required, when a roll-shaped broadband λ / 4 plate is to be manufactured, the broadband λ / 4 plate having a seam defect is obtained.

  On the other hand, a technique called so-called oblique stretching in which a film is stretched at a desired angle with respect to the width direction is known (for example, Patent Document 4). According to this technique, it is possible to produce a stretched film (an obliquely stretched film) having an optical axis in an arbitrary direction that is neither parallel nor orthogonal to the width direction. If such an obliquely stretched film is used, the optical axis of the obliquely stretched film and the absorption axis (or transmission axis) of the polarizing film intersect by roll-to-roll bonding without cutting the film into sheets. Thus, since an obliquely stretched film can be laminated on a polarizing film, a seamless elliptical polarizing plate roll can be produced. However, when a wide band λ / 4 plate is obtained by laminating two obliquely stretched films, the stretched film of λ / 4 constituting this is in a direction of about 60 ° with respect to the optical axis of the stretched film of λ / 2. Although it is necessary to have a slow axis, it is difficult to produce an obliquely stretched film having a large orientation angle in this way.

Further, Patent Document 5 discloses a long laminate in which a λ / 2 plate and a λ / 4 plate are laminated, one of which is composed of a stretched film of a thermoplastic resin and the other of which is a liquid crystal compound. A broadband λ / 4 sheet fabric made of an immobilizing film is disclosed. In this document, a stretched thermoplastic resin film can be produced by oblique stretching (paragraph 0027), and a long-width polarizing plate is laminated on this wide-band λ / 4 plate original and (Paragraph 0057) is also described, and when such a broadband circularly polarizing plate original is used, the above described broadband λ / 4 plate original may be used in place of one protective layer of the polarizing plate. There is also. According to the method described in this document, although a thin and seamless broadband circular polarizing plate raw material can be produced, a polymer film can be cited as an alignment film for aligning a liquid crystal compound. Processing is listed (paragraph 0045). However, in this case, if the long film is to be processed, it is rubbed in an oblique direction while continuously moving the long film, so that it is difficult to keep the rubbing direction constant. On the other hand, as an alignment treatment other than the rubbing treatment, there is a method of irradiating the polymer film with light such as linearly polarized ultraviolet rays from a predetermined direction (paragraph 0047). In this method, however, the polymer film is decomposed by light irradiation. Therefore, since the orientation ability is expressed, the light response is slow, and it is difficult to develop sufficient orientation ability.
JP-A-10-68816 Japanese Patent Laid-Open No. 10-206631 JP 2001-4837 A Japanese Patent Laid-Open No. 50-83482 JP 2004-226686 A

  The present invention has been made in order to solve the above-mentioned problems, and its purpose is to have a good display quality, a simple manufacturing process, a good yield, and a very thin elliptical polarizing plate roll and its It is to provide a manufacturing method. Another object of the present invention is to provide a liquid crystal substrate roll with an elliptical polarizing plate obtained by laminating the elliptical polarizing plate roll and a liquid crystal substrate roll, and a display device using the elliptical polarizing plate roll. It is to provide.

  The present invention includes a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin, a transparent protective film laminated on one surface of the polarizing film via a first adhesive layer, A first retardation plate laminated on the other surface of the polarizing film via a second adhesive layer; a second retardation plate laminated on the first retardation plate; One of the first retardation plate and the second retardation plate is an obliquely stretched film formed by stretching a thermoplastic resin film in an oblique direction with respect to the width direction, and the first position The other of the retardation plate and the second retardation plate is composed of an alignment film and an optically anisotropic layer that is a polymerized layer of a liquid crystalline compound laminated on the alignment film. The molecular weight having a photo-alignment group that brings the alignment ability of the liquid crystal compound by light irradiation is 100- The second retardation plate is formed by coating a composition containing a low-molecular photoalignment compound in the range of 000 and irradiating the resulting coating layer with light, and the second retardation plate is a first retardation plate An elliptically polarizing plate roll having a slow axis in a direction crossing the slow axis is provided.

  Here, in the elliptically polarizing plate roll of the present invention, the in-plane retardation value of the first retardation plate at a wavelength of 550 nm is in the range of 250 to 290 nm, and the in-plane retardation of the second retardation plate at a wavelength of 550 nm. The retardation value is preferably in the range of 125 to 150 nm. The angle formed by the slow axis of the first retardation plate and the absorption axis or transmission axis of the polarizing film is substantially 15 °, and the slow axis of the second retardation plate and the absorption of the polarizing film. The angle formed by the axis or the transmission axis is preferably substantially 75 °.

  The thickness of the first adhesive layer and the second adhesive layer is preferably 1 μm or less. The obliquely stretched film is preferably a stretched film having a thickness of 20 to 60 μm and made of a cycloolefin resin film.

  The photoalignment compound contained in the composition forming the alignment film has a photoalignment group containing a double bond selected from the group consisting of C = C, C = N, N = N, and C = O. Is preferred. The photo-alignment group includes a group having a polyene skeleton, a group having a stilbene skeleton, a group having a stilbazole skeleton, a group having a stilbazolium skeleton, a group having a cinnamoyl skeleton, a group having a hemithioindigo skeleton, a group having a chalcone skeleton, and aromatic A group having a Schiff base skeleton, a group having an aromatic hydrazone skeleton, a group having an azobenzene skeleton, a group having an azonaphthalene skeleton, a group having an aromatic heterocyclic azo skeleton, a group having a bisazo skeleton, a group having a formazan skeleton, It is preferably selected from the group consisting of a group having an azoxybenzene skeleton, a group having a benzophenone skeleton, a group having a coumarin skeleton, and a group having an anthraquinone skeleton.

(Wherein p _{1 to} p ₄ are each independently a hydrogen atom, a halogen atom, a halogenated alkyl group, a halogenated alkoxy group, a cyano group, a nitro group, an alkyl group, an alkoxy group, an aryl group, an allyloxy group, an alkoxy group) It represents a carbonyl group, a carboxyl group, a sulfonic acid group, an amino group, or a hydroxy group.

  The photoalignment compound may further have a polymerizable group containing a carbon-carbon double bond in addition to the photoalignment group. The liquid crystal compound is preferably a rod-like liquid crystal compound.

  The present invention also provides a protective film laminating step of laminating a transparent protective film using an adhesive on one surface of a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin, and a polarizing film Provided is a method for producing an elliptically polarizing plate roll comprising a retardation plate laminating step in which a first retardation plate and a second retardation plate are arranged in this order using an adhesive on the other surface. Here, one of the first retardation plate and the second retardation plate is an obliquely stretched film formed by stretching a thermoplastic resin film in an oblique direction with respect to the width direction thereof. The other of the phase difference plate and the second phase difference plate is composed of an alignment film and an optically anisotropic layer that is a polymerization layer of a liquid crystalline compound laminated on the alignment film (hereinafter referred to as alignment film). And the optically anisotropic layer are also simply referred to as a laminated film.) The alignment film is obtained by applying a composition containing a low-molecular photoalignment compound having a molecular weight in the range of 100 to 5000 having a photoalignment group that brings the alignment ability of the liquid crystal compound by light irradiation. It is formed by irradiating the coating layer with light.

  In the manufacturing method of the elliptically polarizing plate roll of the present invention, when the first retardation plate is an obliquely stretched film, the retardation plate laminating step uses an adhesive to form one surface of the obliquely stretched film as a polarizing film. And a step of forming an alignment film and an optically anisotropic layer in this order on the other surface of the obliquely stretched film. When the second retardation plate is an obliquely stretched film, the retardation plate laminating step forms an alignment film and an optically anisotropic layer in this order on one surface of the obliquely stretched film, and then an adhesive. A step of bonding the optically anisotropic layer to the other surface of the polarizing film.

  When the first retardation plate is an obliquely stretched film, the transparent protective film and the obliquely stretched film are bonded to the polarizing film by rolling the transparent protective film, the roll of the polarizing film, and obliquely stretching. It can carry out simultaneously and continuously by roll-to-roll bonding using a roll-like product of a laminated film in which an alignment film and an optically anisotropic layer are laminated in this order on a film or an obliquely stretched film. In this case, in particular, after the transparent protective film and the obliquely stretched film are bonded to the polarizing film simultaneously and continuously by roll-to-roll bonding, the resulting laminated film is oriented on the obliquely stretched film surface. It is preferable to form the film and the optically anisotropic layer in this order. Moreover, in the case where the second retardation plate is an obliquely stretched film, the transparent protective film and the optically anisotropic layer are bonded to the polarizing film, the transparent protective film roll, the polarizing film roll, Further, it is preferable that the roll-to-roll bonding is performed simultaneously and continuously using a roll-like product of a laminated film in which an alignment film and an optically anisotropic layer are laminated in this order on an obliquely stretched film. .

  The elliptically polarizing plate roll of the present invention can be suitably applied to a liquid crystal substrate roll with an elliptically polarizing plate and a display device. The liquid crystal substrate roll with an elliptically polarizing plate of the present invention is composed of the elliptically polarizing plate roll of the present invention and the liquid crystal cell substrate roll, with the second retardation plate side of the elliptically polarizing plate roll as the bonding surface, To-roll pasted. The display device of the present invention includes an elliptically polarizing plate cut from the elliptically polarizing plate roll of the present invention and a display element. The elliptically polarizing plate is disposed so that the second retardation plate side faces the display element. Examples of the display element include a liquid crystal cell and an organic EL element.

  According to the present invention, it is possible to obtain an elliptically polarizing plate roll having a reduced overall thickness and good display quality in a seamless state. In addition, according to the present invention, such an elliptically polarizing plate roll can be manufactured with a smaller number of steps as compared with the conventional art. In addition, an alignment layer for aligning liquid crystalline compounds is formed by applying a composition containing a low-molecular photoalignment compound and irradiating the coating layer with light. High orientation ability can be easily obtained. And since the elliptically polarizing plate roll of the present invention is thin and has no seam, for example, when cutting from the roll into a sheet, and when laminating the roll with a liquid crystal cell substrate roll, etc. Manufacturing efficiency and yield can be improved, and the elliptically polarizing plate roll of the present invention is suitable for thinning various display devices.

<Elliptically polarizing plate roll>
An example of a basic layer structure of the elliptically polarizing plate roll according to the present invention is shown in a schematic cross-sectional view in FIG. An elliptically polarizing plate roll 100a shown in FIG. 1 (a) includes a polarizing film 101a, a transparent protective film 102a laminated on one surface of the polarizing film 101a via a first adhesive layer 104a, A first retardation plate 103a laminated on the other surface of the polarizing film 101a via a second adhesive layer 105a, and a second retardation laminated on the first retardation plate 103a Plate 108a. In the elliptically polarizing plate roll 100a shown in FIG. 1A, the first retardation plate 103a is formed by stretching a thermoplastic resin film in an oblique direction that is neither parallel nor orthogonal to the width direction. It consists of a diagonally stretched film. On the other hand, the second retardation plate 108a has a stacked structure of an alignment film 106a formed on the first retardation plate 103a and an optically anisotropic layer 107a stacked on the alignment film 106a. Yes. As will be described in detail later, the optically anisotropic layer 107a is a fixed film of a liquid crystal compound obtained by polymerizing a polymerizable liquid crystal compound.

  In the present invention, the first retardation plate laminated on the polarizing film via the second adhesive layer is a laminate of an alignment film and an optically anisotropic layer, and is formed on the first retardation plate. The laminated second retardation plate may be an obliquely stretched film. FIG. 1B shows such an example. That is, the elliptically polarizing plate roll 100b shown in FIG. 1B includes a polarizing film 101b and a transparent protective film 102b laminated on one surface of the polarizing film 101b via the first adhesive layer 104b. A first retardation plate 108b laminated on the other surface of the polarizing film 101b via a second adhesive layer 105b, and a second retardation laminated on the first retardation plate 108b. And a phase difference plate 103b. The first retardation plate 108b has a laminated structure of the alignment film 106b and the optically anisotropic layer 107b. On the other hand, the second retardation plate 103b has a thermoplastic resin film in the width direction. And an obliquely stretched film formed by stretching in an oblique direction.

  According to the elliptically polarizing plate roll of the present invention having the above-described configuration, an adhesive is used for bonding between the transparent protective film and the polarizing film and bonding between the polarizing film and the first retardation plate. Compared to the case of using (pressure-sensitive adhesive), the elliptically polarizing plate can be made thinner and lighter, and the number of constituent members can be reduced. The yield of the display device used can be improved. Furthermore, since an elliptically polarizing plate roll can be manufactured by roll-to-roll bonding using an adhesive, it is possible to simplify the manufacturing process. In the present invention, the elliptically polarizing plate roll is obtained by winding an elliptically polarizing plate having a layer structure as shown in FIG. 1 into a roll shape.

  In the elliptically polarizing plate roll of the present invention, the combination of the first retardation plate and the second retardation plate laminated adjacent thereto can function as a so-called broadband λ / 4 plate. In this case, the first retardation plate is a λ / 2 plate in the broadband λ / 4 plate, and the second retardation plate is a λ / 4 plate in the broadband λ / 4 plate. In order for the first and second retardation plates to perform such a function, the slow axis of the second retardation plate needs to intersect the slow axis of the first retardation plate. More specifically, the angle formed between the slow axis of the first retardation plate that is a λ / 2 plate and the slow axis of the second retardation plate that is a λ / 4 plate is substantially equal to It is set to 60 °. Substantially 60 ° means that about ± 5 ° is allowed around 60 °, specifically, it can be in the range of 55 to 65 °. In order to function as a broadband λ / 4 plate, the angle formed by the slow axis of the first retardation plate and the absorption axis or transmission axis of the polarizing film is substantially 15 °, and the second position. The angle formed by the slow axis of the retardation film and the absorption axis or transmission axis of the polarizing film is preferably substantially 75 °. Here, “substantially 15 ° and substantially 75 °” means that about ± 5 ° is allowed around each angle, specifically, 10 to 20 ° and 70 to 80, respectively. Can be in the range of °.

  In order to make the first retardation plate a λ / 2 plate in a broadband λ / 4 plate, the in-plane retardation value at a wavelength of 550 nm is preferably in the range of 250 to 290 nm. In order to make the second retardation plate a λ / 4 plate in a broadband λ / 4 plate, the in-plane retardation value at a wavelength of 550 nm is preferably in the range of 125 to 150 nm. Here, the in-plane retardation value means the front phase difference, and is calculated by multiplying the difference between the maximum in-plane refractive index and the refractive index in the direction orthogonal thereto by the thickness of each retardation plate.

Hereinafter, the elliptically polarizing plate roll of the present invention will be described in more detail.
(Polarizing film)
The polarizing film in the present invention means a linear polarizer and has a function of selectively transmitting linearly polarized light in one direction from natural light. Examples of the polarizing film include polyvinyl polarizing films such as an iodine polarizing film in which iodine is adsorbed and oriented on a polyvinyl alcohol resin film, and a dye polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin film. Examples thereof include a polarizing film in which a dichroic dye is adsorbed and oriented on an alcohol resin film. In addition to this, there is also a polarizing film coated with a dichroic dye on a base resin film, oriented and fixed, and called a coating type polarizing film, but when the base resin film is a polyvinyl alcohol resin, Can also be used as a polarizing film in the present invention. These iodine-based polarizing film, dye-based polarizing film, and coating-type polarizing film have a function of selectively transmitting linearly polarized light in one direction from natural light and absorbing linearly polarized light in the other direction. Also called a polarizer. Among these polarizing films, it is preferable to use a polarizing film obtained by dyeing a polyvinyl alcohol-based resin film with a dichroic dye from the viewpoint of optical performance. Among them, an iodine-based polarizing film having excellent polarization degree and transmittance is used. Is most preferred.

  The polyvinyl alcohol-based resin film can be obtained by forming a polyvinyl alcohol-based resin. The polyvinyl alcohol resin can be obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The saponification degree of the polyvinyl alcohol resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The degree of polymerization of the polyvinyl alcohol resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000. The polyvinyl alcohol resin may be modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used.

  The method for forming a polyvinyl alcohol-based resin is not particularly limited, and can be formed by a known method. Although the film thickness of a polyvinyl alcohol-type resin film (raw film) is not specifically limited, For example, it is about 1 micrometer-150 micrometers, Preferably it is about 20 micrometers-100 micrometers.

  The polarizing film is usually a step of uniaxially stretching the polyvinyl alcohol-based resin film, a step of dyeing the polyvinyl alcohol-based resin film with a dichroic dye, and adsorbing the dichroic dye, a polyvinyl on which the dichroic dye is adsorbed The alcohol-based resin film is manufactured through a step of treating with an aqueous boric acid solution and a step of washing with water after the treatment with the aqueous boric acid solution.

  Uniaxial stretching may be performed before dyeing, simultaneously with dyeing, or after dyeing. When uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Of course, it is also possible to perform uniaxial stretching in these plural stages. In uniaxial stretching, it may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. Moreover, the dry-type extending | stretching which extends | stretches in air | atmosphere may be sufficient, and the wet extending | stretching which extends | stretches in the state swollen with the solvent may be sufficient. The draw ratio is usually about 4 to 8 times.

  Examples of a method for dyeing a polyvinyl alcohol resin film with a dichroic dye include a method of immersing a polyvinyl alcohol resin film in an aqueous solution containing a dichroic dye. In addition, it is preferable that the polyvinyl alcohol-type resin film performs the immersion process to water before a dyeing process.

  When iodine is used as the dichroic dye, a method of dyeing a polyvinyl alcohol resin film by dipping it in an aqueous solution containing iodine and potassium iodide is usually employed. The content of iodine in this aqueous solution is usually about 0.01 to 1 part by weight per 100 parts by weight of water, and the content of potassium iodide is usually about 0.5 to 20 parts by weight per 100 parts by weight of water. . The temperature of the aqueous solution used for dyeing is usually about 20 to 40 ° C., and the immersion time (dyeing time) in this aqueous solution is usually about 20 to 1,800 seconds.

  The boric acid treatment after dyeing with the dichroic dye can be performed by immersing the dyed polyvinyl alcohol-based resin film in a boric acid-containing aqueous solution. The amount of boric acid in the boric acid-containing aqueous solution is usually about 2 to 15 parts by weight, preferably about 5 to 12 parts by weight per 100 parts by weight of water. When iodine is used as the dichroic dye, this boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually 40 parts by weight or less, preferably 30 parts by weight or less per 100 parts by weight of water. The immersion time in the boric acid-containing aqueous solution is usually about 60 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. Moreover, the temperature of boric-acid containing aqueous solution is 50 degreeC or more normally, Preferably it is 50-85 degreeC.

  The polyvinyl alcohol resin film after the boric acid treatment is usually washed with water. The water washing treatment can be performed, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. The temperature of water in the water washing treatment is usually about 5 to 40 ° C., and the immersion time is usually about 1 to 120 seconds.

  A polarizing film can be obtained by performing a drying process on the polyvinyl alcohol-based resin film that has undergone the above-described series of steps. The drying treatment can be performed using a hot air dryer or a far infrared heater. The drying temperature is usually 40 to 100 ° C. The time for the drying treatment is usually about 120 to 600 seconds. The thickness of the finally obtained polarizing film is about 5 to 40 μm. In such a polarizing film, since the dichroic dyes are arranged in the stretching direction, the stretching direction becomes the absorption axis. That is, when stretching is performed by uniaxial stretching, the longitudinal direction of the long polarizing film obtained as a roll body is the absorption axis.

(Transparent protective film)
A transparent protective film is laminated on one side of the polarizing film via a first adhesive layer. Thereby, the polarizing film surface of the elliptically polarizing plate which can be used in a wide variety of environments can be protected. Examples of the transparent protective film include a cellulose resin film, an acrylic resin film, a polyester resin film, a polyarylate resin film, a polyether sulfone resin film, and a cycloolefin resin film using cycloolefin as a monomer such as norbornene. It is done. Moreover, a transparent protective film is not limited to a film-form thing, For example, you may be the transparent protective layer formed by coating. Although the thickness in particular of a transparent protective film is not restrict | limited, Usually, it is about 20-100 micrometers, and it is preferable that it is 20-40 micrometers from a viewpoint of thickness reduction of an elliptically polarizing plate.

  The cellulose-based resin film is preferably a cellulose acetate-based resin film in which at least a part of cellulose is acetated. Examples of such include triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate. Examples of commercially available triacetyl cellulose films include “Fujitac Film” (available in various grades) sold by Fuji Film Co., Ltd., “KC8UX2M”, “KC8UY” sold by Konica Minolta Opto Co., Ltd. ”,“ KC4UY ”, etc. (all are trade names).

  When using a cellulose acetate-based resin film as the transparent protective film, it is preferable to saponify the cellulose acetate-based resin film in order to enhance the adhesion to the polarizing film. As the saponification treatment, a method of immersing in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide can be employed.

  The surface of the transparent protective film (surface opposite to the polarizing film side) is subjected to surface treatments such as antiglare treatment, hard coat treatment, antistatic treatment, and antireflection treatment according to the use of the elliptically polarizing plate. May be.

(Obliquely stretched film)
The obliquely stretched film is a film produced by stretching a thermoplastic resin film in an oblique direction that is neither parallel nor orthogonal to the width direction, and the first retardation of the elliptically polarizing plate roll of the present invention. Used for either the plate or the second retardation plate. Such an obliquely stretched film crosses the slow axis of the retardation film made of the stretched film, the absorption axis or transmission axis of the polarizing film, and the slow axis of the other retardation plate at a predetermined angle so that the visible film is visible. When manufacturing an elliptically polarizing plate roll capable of obtaining circularly polarized light over the entire region, it can be used as a roll body without being cut into single sheets. It is possible to adopt a roll method, which contributes to a significant simplification of the manufacturing process.

  The thermoplastic resin is not particularly limited as long as it has good transparency. For example, a polyolefin polymer, a polycarbonate polymer, a polyester polymer, a polystyrene polymer, a polysulfone polymer, a poly Examples include ether sulfone polymers and polyvinyl alcohol polymers. Among them, in the present invention, since a liquid crystalline compound is applied on an obliquely stretched film, it is preferable to use a material having low hygroscopicity and excellent dimensional stability, and a preferred example is a cycloolefin resin. Can do. Examples of the cycloolefin resin include thermoplastic resins having units derived from cycloolefin monomers such as norbornene and polycyclic norbornene monomers. More specifically, the cycloolefin-based resin includes a hydrogenated product of a ring-opening polymer of the cycloolefin monomer, a hydrogenated product of a ring-opening copolymer using two or more types of cycloolefin monomers, and a cycloolefin. An addition copolymer of a monomer and a chain olefin monomer or an aromatic compound having a vinyl group may be used. Moreover, the polar group may be introduce | transduced into cycloolefin type resin.

  Examples of the chain olefin monomer include ethylene and propylene. Examples of the aromatic compound having a vinyl group include styrene, α-methylstyrene, and nuclear alkyl-substituted styrene. In the case where the cycloolefin resin is an addition copolymer of a cycloolefin monomer and a chain olefin monomer or an aromatic compound having a vinyl group, the unit derived from the cycloolefin monomer is 50 mol% or less, for example, 15 to 15%. It may be about 50 mol%. In particular, when a terpolymer of a cycloolefin monomer, a chain olefin monomer, and an aromatic compound having a vinyl group is used, the amount of units derived from the cycloolefin monomer can be relatively small. In such a ternary copolymer, the unit derived from a chain olefin monomer is usually about 5 to 80 mol%, and the unit derived from an aromatic compound having a vinyl group is usually about 5 to 80 mol%.

  Commercially available thermoplastic cycloolefin-based resins include “Topas” sold by Ticona, Germany, “Arton” sold by JSR Corporation, and “Zeonor” sold by Nippon Zeon Corporation. ZEONOR ”and“ ZEONEX ”,“ Apel ”sold by Mitsui Chemicals, Inc. (all are trade names). A film can be obtained by forming such a cycloolefin resin. For film formation, a known film formation method such as a solvent casting method or a melt extrusion method is appropriately used. In addition, the formed cycloolefin-based resin film is also commercially available. For example, “Essina” and “SCA40” sold by Sekisui Chemical Co., Ltd., “Zeonor film” sold by Optes Co., Ltd. ”And“ Arton Film ”(all are trade names) sold by JSR Corporation.

  The thermoplastic resin film as described above is subjected to an orientation treatment in a direction oblique to the width direction by a known stretching method to obtain an obliquely stretched film to which an appropriate retardation is imparted. The oblique stretching method is not particularly limited as long as the orientation axis can be continuously inclined to a desired angle, and can be carried out by a known method. Examples thereof include those described in JP-A-50-83482 and JP-A-2-113920. Specifically, while unwinding the thermoplastic resin film from the roll, the conveyance direction and tension are adjusted continuously in the heating furnace when stretching in the roll traveling direction or in the direction perpendicular to the traveling direction. However, it is possible to adopt a method of performing uniaxial or biaxial thermal stretching with an inclination at an arbitrary angle. As the temperature of the heating furnace, a range of from the vicinity of the glass transition temperature of the thermoplastic resin to the glass transition temperature + 100 ° C., preferably the range of the glass transition temperature + 50 ° C. is usually employed. The draw ratio is usually about 1.1 to 6 times, preferably 1.1 to 3.5 times.

  The thickness of the thermoplastic resin film is preferably thin. However, if the thickness is too thin, the strength is lowered and the processability is inferior. On the other hand, if the thickness is too thick, the transparency is lowered and the weight is increased. Arise. Further, the thickness of the obliquely stretched film obtained by obliquely stretching the thermoplastic resin film is determined by the thickness of the thermoplastic resin film, the stretch ratio, the target retardation value, etc. The strength is insufficient or the retardation value is insufficient, and if it is too thick, the transparency is lowered or it is difficult to obtain the desired retardation value, and it is also not preferable from the viewpoint of reducing the thickness and weight of the elliptically polarizing plate. Absent. Therefore, it is appropriate for the thickness of the obliquely stretched film to be, for example, about 5 to 200 μm, and preferably 20 to 100 μm. From the viewpoint of reducing the thickness and weight of the elliptically polarizing plate roll, the thickness of the obliquely stretched film is more preferably about 20 to 60 μm.

(First adhesive layer and second adhesive layer)
In the present invention, the transparent protective film is laminated on one surface of the polarizing film via a first adhesive layer, and the first retardation plate is a second adhesive on the other surface of the polarizing film. Laminated through layers. Examples of the adhesive that forms the first and second adhesive layers include a water solvent adhesive, an organic solvent adhesive, a hot melt adhesive, and a solventless adhesive. The adhesive used for laminating the transparent protective film and the adhesive used for laminating the first retardation plate may be the same or different.

  Examples of the adhesives that can be used in the present invention include, for example, monomer / oligomer adhesives such as (meth) acrylates and oxetanes; urea resins, melamine resins, phenol resins, resorcinol resins Resin adhesives such as epoxy, urethane resin, vinyl acetate resin, polyvinyl alcohol resin, acrylic resin, cellulose resin; chloroprene, nitrile rubber, styrene butadiene rubber, styrene block copolymer thermoplastic Examples thereof include rubber adhesives such as elastomers, butyl rubbers, natural rubbers, recycled rubbers, chlorinated rubbers and silicone rubbers; natural adhesives such as glues and starches. More specifically, examples of the aqueous solvent-based adhesive include an aqueous solution of a polyvinyl alcohol resin, an aqueous two-component urethane emulsion adhesive using a urethane resin, and the like. Examples of the organic solvent-based adhesive include a two-component urethane-based adhesive using a urethane resin. Examples of the solventless adhesive include a one-component urethane adhesive using a urethane resin. In particular, in the present invention, from the viewpoint of reducing the thickness of the elliptically polarizing plate roll, an adhesive capable of making the thickness of the adhesive layer after drying, that is, the first and second adhesive layers 1 μm or less, is used. It is preferable to select, and as such an adhesive, a water-based adhesive, that is, an adhesive in which an adhesive component is dissolved in water or a dispersion in water can be mentioned as a preferable one. As the water-based adhesive, for example, an aqueous composition using a polyvinyl alcohol resin or a urethane resin as a main component is suitable.

  When a polyvinyl alcohol-based resin is used as the main component of the adhesive, the polyvinyl alcohol-based resin includes partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, as well as carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, and methylol group. Modified polyvinyl alcohol resins such as modified polyvinyl alcohol and amino group-modified polyvinyl alcohol may also be used. When the polyvinyl alcohol resin is the main component of the adhesive, the adhesive is usually an aqueous solution of a polyvinyl alcohol resin. The density | concentration of the polyvinyl alcohol-type resin in an adhesive agent is about 1-10 weight part normally with respect to 100 weight part of water, Preferably it is 1-5 weight part.

  In order to improve the adhesiveness, it is preferable to add a curable component such as glyoxal or a water-soluble epoxy resin or a crosslinking agent to the adhesive comprising an aqueous solution of a polyvinyl alcohol resin. Examples of water-soluble epoxy resins include polyamide polyamine epoxy resins obtained by reacting epichlorohydrin with polyamide polyamines obtained by reaction of polyalkylene polyamines such as diethylenetriamine and triethylenetetramine with dicarboxylic acids such as adipic acid. Can be used. Commercially available products of such polyamide polyamine epoxy resins include “Smiles Resin 650”, “Smiles Resin 675” sold by Sumika Chemtex Co., Ltd., and “WS-525” sold by Japan PMC Co., Ltd. "and so on. The addition amount of these curable components or crosslinking agents is usually 1 to 100 parts by weight, preferably 1 to 50 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. If the amount added is small, the effect of improving the adhesiveness is reduced, while if the amount added is large, the adhesive layer tends to be brittle.

  Moreover, as a suitable example of the adhesive agent which has a urethane resin as a main component, the water-system adhesive agent containing a polyester-type ionomer type urethane resin can be mentioned. Here, the polyester ionomer type urethane resin is a urethane resin having a polyester skeleton, and a small amount of an ionic component (hydrophilic component) is introduced into the molecule. Such a polyester ionomer type urethane resin is suitable as a water-based adhesive because it is emulsified directly in water without using an emulsifier and becomes an emulsion. Polyester ionomer-type urethane resins are known per se, and are described, for example, in JP-A-7-97504 as examples of polymer dispersants for dispersing phenolic resins in an aqueous medium. JP-A-2005-70140 and JP-A-2005-208456 disclose a polarizing film made of a polyvinyl alcohol resin using a mixture of a polyester ionomer type urethane resin and a compound having a glycidyloxy group as an adhesive. The form which joins a cycloolefin system resin film is shown.

  The polyester ionomer type urethane resin can be produced, for example, by a method in which a hydrophilic group-containing urethane resin obtained by reacting a hydrophilic group-containing compound, a polyester polyol and a polyisocyanate is emulsified in water. In this case, in addition to the polyester polyol, other high molecular weight polyol components and low molecular weight active hydrogen-containing compounds may be used in combination. Examples of the high molecular weight polyol component include polyether polyol, polycarbonate polyol, polyacetal polyol, polyacrylate polyol, polyesteramide polyol, polythioether polyol, and the like. Examples of the low molecular weight active hydrogen-containing compound include polyhydroxy compounds such as ethylene glycol, neopentyl glycol, 1,6-hexanediol, glycerin and trimethylolpropane; and diamine compounds such as ethylenediamine and piperazine. Among them, it is preferable to use a low molecular weight active hydrogen-containing compound in combination.

  The polyester ionomer type urethane resin preferably has a weight average molecular weight of 5,000 or more, more preferably 10,000 or more and 300,000 or less. If the weight average molecular weight is less than 5,000, sufficient strength of the adhesive layer cannot be obtained, and if it is greater than 300,000, the viscosity of the aqueous adhesive containing it tends to be difficult to handle. It is in.

  An aqueous adhesive mainly composed of a polyester ionomer type urethane resin is usually in the form of an aqueous dispersion in which the urethane resin is dispersed in water. The viscosity of the aqueous adhesive is preferably 2,000 mPa · sec or less, more preferably 1,000 mPa · sec or less, and particularly preferably 500 mPa · sec or less. The lower the viscosity, the easier the application of the adhesive and the better the appearance of the resulting elliptically polarizing plate. The solid content concentration of the polyester ionomer type urethane resin in this water-based adhesive is preferably in the range of 10 to 70% by weight, more preferably 20% by weight or more, and 50% by weight from the viewpoint of viscosity and adhesive strength. The following is more preferable.

  Polyethylene glycol, polyoxyethylene, a surfactant, and the like may be further added to the water-based adhesive mainly composed of a polyester ionomer type urethane resin. In addition, water-soluble resins such as polyhydroxyethyl methacrylate, polyhydroxyethyl acrylate, polyacrylic acid, and polyvinyl alcohol resins may be added.

  Examples of commercially available polyester ionomer type urethane resins include “Hydran AP-20” and “Hydran APX-101H” sold by DIC Corporation.

  Moreover, it is preferable that the water-system adhesive which has a polyester-type ionomer type urethane resin as a main component further contains the compound which has a glycidyloxy group. By using together the compound which has a glycidyloxy group, the adhesiveness of a polarizing film and the cycloolefin type-resin film which can be used as a transparent protective film or a diagonally stretched film can be improved. Here, the glycidyloxy group means a 2,3-epoxypropoxy group. Examples of the compound having a glycidyloxy group include, for example, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, diglycerin diglycidyl ether, ethylene glycol diglycidyl. Ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, resorcin diglycidyl ether, glycerin triglycidyl ether, Trimethylolpropane triglycidyl ether, pentaerythritol polyglycidyl Ether, sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, polyglycerol polyglycidyl ether, and the like.

  The mixing ratio of the polyester ionomer type urethane resin and the compound having a glycidyloxy group is such that the compound having a glycidyloxy group is about 5 to 100 parts by weight with respect to 100 parts by weight of the solid content of the polyester ionomer type urethane resin. It is preferable to select appropriately such that the compound having a glycidyloxy group is in the range of 5 to 60 parts by weight, particularly 5 to 30 parts by weight. If the ratio of the compound having a glycidyloxy group is lowered too much, sufficient adhesive strength cannot be obtained, and if the ratio is too large, the viscosity of the adhesive tends to be high and handling tends to be difficult.

  A water-based adhesive containing a polyester ionomer-type urethane resin and a compound having a glycidyloxy group does not require the use of an organic solvent, so there is no risk of causing environmental or worker health problems. At the same time, the use of a compound having a glycidyloxy group gives high adhesive strength.

  Further, the water-based adhesive mainly composed of a polyester ionomer type urethane resin may contain an isocyanato group-containing compound, particularly a polyisocyanate compound having at least two isocyanato groups in the molecule. Thereby, the adhesiveness with respect to the cellulose acetate type-resin film which can be used as a transparent protective film can be improved. Examples of such isocyanato group-containing compounds include monomers or oligomers such as 2,4-tolylene diisocyanate, phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, and the like. The reaction material of a compound and a polyol is mentioned. Examples of the polyol include 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and the like. The molecular weight of these isocyanato group-containing compounds is preferably 5,000 or less in terms of weight average molecular weight even in the case of reaction products with the above oligomers and polyols. Examples of suitable commercially available isocyanato group-containing compounds include “Hydran Assist C1” sold by DIC Corporation.

  The mixing ratio of the polyester ionomer type urethane resin and the isocyanato group-containing compound is suitably set so that the isocyanate group-containing compound is in the range of about 5 to 100 parts by weight with respect to 100 parts by weight of the solid content of the polyester ionomer type urethane resin. It is preferable to select, and more preferably, the isocyanato group-containing compound is selected in the range of 5 to 60 parts by weight, particularly 5 to 30 parts by weight. If the ratio of the isocyanato group-containing compound is too low, sufficient adhesive strength cannot be obtained, and if the ratio is too high, the viscosity of the adhesive tends to be high and handling tends to be difficult.

  Here, the bonding between the polarizing film using the adhesive and the transparent protective film and the polarizing film and the first retardation plate (in addition, as will be described in detail later, this first at the time of bonding with the polarizing film. The phase difference plate may be a laminate with the second phase difference plate.) The bonding may be performed in a separate process or in parallel. The latter is preferable from the viewpoint of simplifying the manufacturing process. The method of bonding the first retardation plate and the transparent protective film to the polarizing film using an adhesive may be a generally known method, for example, a casting method, a Mayer bar coating method, a gravure coating, or the like. Examples thereof include a method in which an adhesive is applied to the adhesive surface of a polarizing film and / or a film to be bonded to the polarizing film and the both are overlapped by a method, a die coating method, a dip coating method, a spraying method, or the like. The casting method is a method of spreading and spreading an adhesive on the surface of a film to be coated while moving it in a substantially vertical direction, a substantially horizontal direction, or an oblique direction between the two. After apply | coating an adhesive agent, a polarizing film and the film bonded by this are pinched | interposed by a nip roll etc., and are bonded together.

  In addition, in order to improve adhesiveness, the surface of the polarizing film and / or the film to be bonded to the polarizing film may be previously treated with plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, saponification treatment, etc. A surface treatment may be applied as appropriate. Examples of the saponification treatment include a method of immersing in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide.

  Next, curing of the adhesive will be described by taking as an example a case where the polarizing film and the transparent protective film are bonded together and the polarizing film and the first retardation plate are bonded simultaneously. A bonded body including a transparent protective film, a polarizing film, and a first retardation plate formed using an adhesive is usually subjected to heat treatment and / or irradiation treatment with active energy rays. Thereby, while the solvent component in an adhesive agent is dried, hardening of an adhesive agent component arises and the adhesiveness between films becomes strong.

  When heat-processing with respect to the said bonded body, an adhesive agent is hardened | cured when the adhesive agent component superposes | polymerizes or the solvent in an adhesive agent is removed by drying. Although heat processing conditions are not specifically limited, Since heating at high temperature causes deterioration of the said bonding body, it is preferable to implement on about 20-120 degreeC temperature conditions.

  When the adhesive is cured by drying the solvent in the adhesive, the drying temperature is usually in the range of about 30 to 85 ° C, preferably about 40 to 80 ° C. The dried laminate is cured under a temperature environment of about 15 to 85 ° C., preferably about 20 to 50 ° C., more preferably about 35 to 45 ° C. in order to make the curing of the adhesive more complete. Also good. The curing period is usually about 1 to 90 days. However, if the curing period is long, the productivity deteriorates, and therefore it is preferably about 1 to 30 days, and more preferably about 1 to 7 days.

On the other hand, when the adhesive is cured by irradiation with active energy rays, the light source to be used is not particularly limited. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, or the like can be used. The light irradiation intensity is not particularly limited, but the irradiation intensity peak at the absorption wavelength of the photoinitiator contained in the adhesive is preferably 10 to 10,000 mW / cm ² . When the light irradiation intensity is less than 10 mW / cm ^2, too long reaction time exceeds 10,000 mW / cm ^2, which may cause degradation of the bonded body by radiation heat from the lamp. The light irradiation time is not particularly limited, but is preferably set so that the integrated light amount represented by the product of the irradiation intensity and the irradiation time is 10 to 10,000 mJ / cm ² . When integrated quantity of light is less than 10 mJ / cm ^2, there is a possibility that the curing of the adhesive does not sufficiently proceed, while the accumulated light amount is more than 10,000 / cm ^2, can result in degradation of the bonded body is there.

  Even if it is a case where it hardens | cures on any conditions of a heating or active energy ray irradiation, it is preferable to harden in the range which does not reduce the various functions of a polarizing film or a phase difference plate.

(Alignment film and optically anisotropic layer)
The laminated film composed of the alignment film and the optically anisotropic layer functions as a retardation plate. When the diagonally stretched film is the first retardation plate of the elliptically polarizing plate roll of the present invention, the laminated film becomes the second retardation plate. In this case, the laminated film composed of the alignment film and the optically anisotropic layer is arranged so that the alignment film is on the obliquely stretched film side (see FIG. 1A). In addition, even when the obliquely stretched film is the second retardation plate, the laminated film composed of the orientation film and the optically anisotropic layer is arranged so that the orientation film is on the obliquely stretched film side (optically anisotropic). The adhesive layer is disposed on the second adhesive layer side (see FIG. 1B). In any case, the second retardation plate has a slow axis in a direction intersecting with the slow axis of the first retardation plate. The angle formed by the slow axis is substantially 60 ° as described above. Hereinafter, the alignment film and the optically anisotropic layer will be described in detail.

  The alignment film is a composition containing a photo-alignment compound (hereinafter referred to as a photo-alignment composition) that generates an ability to align a liquid crystal compound applied on the alignment film (hereinafter, liquid crystal alignment ability) by light irradiation. Is applied onto the obliquely stretched film to form the photoalignable composition layer (A), and then the photoalignable composition layer (A) is irradiated with light to form a photoalignable composition. It can be obtained by imparting liquid crystal alignment ability to the physical layer (A). By forming such an alignment film, the liquid crystalline compound constituting the optically anisotropic layer formed on the alignment film can be uniformly aligned in a predetermined direction. The predetermined direction is preferably a direction in which the angle formed with the slow axis of the obliquely stretched film is substantially 60 °. The application of liquid crystal alignment ability using such light irradiation (photo-alignment method) is easier to operate than conventional rubbing alignment methods, and in particular, according to the photo-alignment method, roll-to- In the case of manufacturing an elliptically polarizing plate roll by a roll method, it is possible to continuously perform orientation treatment on a long film. The photo-alignment method is effective when aligning the liquid crystalline compound at a large angle with respect to the slow axis of the obliquely stretched film. As will be described later, the photoalignable composition layer (A) to which liquid crystal alignment ability is imparted is intended to improve the adhesion to the optically anisotropic layer and the durability of the resulting elliptically polarizing plate roll. It is preferable to polymerize together with the liquid crystal composition layer (B) described later. In the present invention, the alignment film includes both a polymerized and non-polymerized state of the photoalignable composition layer (A) to which the liquid crystal alignment ability is imparted.

  The optically anisotropic layer is formed by applying a composition containing a liquid crystal compound (hereinafter referred to as a liquid crystal composition) on the alignment film to form a liquid crystal composition layer (B), and then forming the liquid crystal composition layer. (B) can be obtained by polymerization and curing with an active energy ray or heat. That is, the optically anisotropic layer is composed of a polymerized layer of a liquid crystalline compound. The liquid crystalline compound in such a polymerized layer is imparted with orientation due to the influence of the orientation film.

A method for producing a laminated film composed of an alignment film serving as the first or second retardation plate and an optically anisotropic layer will be described more specifically. In the present invention, the laminated film is preferably formed through the following steps.
(A) A step of applying a photoalignable composition on the above-described obliquely stretched film to form a photoalignable composition layer (A),
(B) a step of irradiating the photo-alignment composition layer (A) with light, imparting liquid crystal alignment ability to the photo-alignment composition layer (A), and obtaining an alignment film;
(C) A step of applying a liquid crystal composition on the photo-alignable composition layer (A) (alignment film) to which liquid crystal alignment ability is imparted, and forming a liquid crystal composition layer (B);
(D) A step of polymerizing the liquid crystal composition layer (B) by irradiation with active energy rays or heating together with the photo-alignment composition layer (A) preferably imparted with liquid crystal alignment ability.

(A) Step of forming photo-alignable composition layer (A) The photo-alignable composition used for forming the photo-alignable composition layer (A) is a photo-alignable compound that produces liquid crystal aligning ability by light irradiation. contains. Photo-alignment compounds are molecules induced by the Weigert effect caused by photo-dichroism caused by photoirradiation or isomerization reaction (eg azobenzene group), dimerization reaction (eg cinnamoyl group), photocrosslinking reaction (example) : A benzophenone group) or a group that causes a photoreaction that brings about liquid crystal alignment ability (hereinafter referred to as a photoalignable group), such as a photodecomposition reaction (eg, a polyimide group). Among these, photo-alignment compounds utilizing molecular orientation induction or isomerization reaction, dimerization reaction, or photo-crosslinking reaction due to Weigert effect due to photodichroism are excellent in photo-alignment property, and liquid crystalline compounds can be easily used. This is preferable because it can be oriented.

  The photo-alignment group is not particularly limited as long as it imparts the alignment ability of a liquid crystal compound to be applied later. Preferred examples include C = C, C = N, N = N, and C = Examples thereof include a group having at least one double bond selected from the group consisting of O (excluding a double bond forming an aromatic ring).

  Examples of the photoalignable group having a C═C bond include a group having a polyene skeleton, a group having a stilbene skeleton, a group having a stilbazole skeleton, a group having a stilbazolium skeleton, a group having a cinnamoyl skeleton, and a group having a hemithioindigo skeleton And a group having a chalcone skeleton. Examples of the group having a C═N bond include a group having an aromatic Schiff base skeleton and a group having an aromatic hydrazone skeleton. Examples of the group having an N = N bond include a group having an azobenzene skeleton, a group having an azonaphthalene skeleton, a group having an aromatic heterocyclic azo skeleton, a group having a bisazo skeleton, a group having a formazan skeleton, and azoxybenzene. And a group having a skeleton. Examples of the group having a C═O bond include a group having a benzophenone skeleton, a group having a coumarin skeleton, and a group having an anthraquinone skeleton. These photo-alignment groups are usually located at the center of the molecule and are often divalent groups.

  An example of a photoalignable group having a C═C bond will be described. Polyene is a compound in which carbon-carbon double bonds (C═C) and carbon-carbon single bonds (C—C) appear alternately, as represented by butadiene, and a group having a polyene skeleton is like this Usually a divalent group derived from a polyene.

  Stilbene is a compound having the structure of the following formula, and the group having a stilbene skeleton is usually a divalent group derived from such stilbene (which may have a substituent).

  Stilbazole is a compound having the structure of the following formula, and the group having a stilbazole skeleton is usually a divalent group derived from such stilbazole (which may have a substituent).

  Stilbazolium is a compound in which the nitrogen atom constituting the pyridine ring in stilbazole is quaternized, and the group having a stilbazolium skeleton is derived from such stilbazolium (which may have a substituent). It is usually a divalent group.

  The cinnamoyl group is a monovalent group having the following structure, and the group having a cinnamoyl skeleton is usually a divalent group derived from such a cinnamoyl group (which may have a substituent). It is a group.

  The hemithioindigo group is a monovalent group having the structure of the following formula, which is a half crack of thioindigo, and the group having a hemithioindigo skeleton is derived from such a hemithioindigo group (which may have a substituent). Usually, it is a divalent group.

  The chalcone is a compound having a structure of the following formula, and the group having a chalcone skeleton is usually a divalent group derived from such a chalcone (which may have a substituent).

Next, an example of a photo-alignment group having a C═N bond will be described. The Schiff base is a general term for a compound RCR ₁ = NR ₂ produced by dehydration condensation of an aldehyde or ketone and a primary amine, and a compound in which the aldehyde or ketone component is an aromatic compound is called an aromatic Schiff base. A typical example of an aromatic Schiff base can be represented by the formula: ArCR ₁ = NR ₂ , where Ar is an aromatic ring such as a benzene ring, R ₁ is an aromatic ring, an alicyclic ring, It is an aliphatic group or a hydrogen atom, and R ₂ is an aromatic ring, an alicyclic ring or an aliphatic group. Therefore, the group having an aromatic Schiff base skeleton is usually a divalent group derived from such an aromatic Schiff base (which may have a substituent).

  A hydrazone is a condensation product of a carbonyl compound and hydrazine, and the carbonyl compound having an aromatic group is called an aromatic hydrazone. Therefore, a typical example of an aromatic hydrazone is a benzaldehyde hydrazone having the following structure, and the group having an aromatic hydrazone skeleton is derived from such an aromatic hydrazone (which may have a substituent). It is usually a divalent group.

  Next, an example of a photoalignable group having an N = N bond will be described. Azobenzene is a compound having the structure of the following formula, and the group having an azobenzene skeleton is usually a divalent group derived from such azobenzene (which may have a substituent).

  Azonaphthalene is a compound having the structure of the following formula, and a group having an azonaphthalene skeleton is usually a divalent group derived from such azonaphthalene (which may have a substituent). is there.

  The aromatic heterocyclic azo compound is a compound having an aromatic heterocyclic ring such as pyridine and an azo group, and typical examples thereof include phenylazopyridine and azobispyridine. The group having an aromatic heterocyclic azo skeleton is usually a divalent group derived from such an aromatic heterocyclic azo compound (which may have a substituent).

  The bisazo compound is usually a compound having three aromatic rings and two azo bonds. As a typical example, a compound having the structure of the following formula can be mentioned, wherein Ar means an aromatic ring including a benzene ring, a naphthalene ring, a biphenyl ring and the like. The group having a bisazo skeleton is usually a divalent group derived from such a bisazo compound (which may have a substituent).

Formazan is a compound having a structure of NH ₂ N═CHN═NH. Typically, a compound in which two or three hydrogen atoms are substituted with an aromatic ring is referred to as a formazan compound. As a typical example of the formazan compound, a compound having the structure of the following formula can be given. The group having a formazan skeleton is derived from such a formazan compound (which may have a substituent). It is usually a divalent group.

  Azoxybenzene is a compound having the structure of the following formula, and the group having an azoxybenzene skeleton is usually divalent derived from such an azoxybenzene (which may have a substituent). It is the basis of.

  Next, an example of a photoalignable group having a C═O bond will be described. A benzophenone is a compound having a structure of the following formula, and a group having a benzophenone skeleton is usually a divalent group derived from such a benzophenone (which may have a substituent).

  Coumarin is a compound having the structure of the following formula, and a group having a coumarin skeleton is usually a divalent group derived from such a coumarin (which may have a substituent).

  Anthraquinone is a compound having the structure of the following formula, and the group having an anthraquinone skeleton is usually a divalent group derived from such anthraquinone (which may have a substituent).

  These photo-alignment groups may have a substituent as described above. Examples of the substituent include an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfone group. Examples include acid groups and halogenated alkyl groups. These substituents are usually present on an aromatic ring such as a benzene ring. Among the photo-alignment groups described above, a group having an azobenzene skeleton exhibiting photo-alignment by a photoisomerization reaction, a group having a bisazo skeleton and a group having an anthraquinone skeleton, and a benzophenone exhibiting photo-alignment by a photo-dimerization reaction A group having a skeleton, a group having a cinnamoyl skeleton, a group having a chalcone skeleton, and a group having a coumarin skeleton have a small amount of light irradiation necessary for photo-alignment, and the resulting alignment film has thermal stability and stability over time. Since it is excellent, it is more preferable.

  The photoalignment compound preferably contains a polymerizable group together with the photoalignment group. When the photoalignment compound has a polymerizable group, when the liquid crystal composition layer (B) is polymerized (step (d)), the photoalignment composition layer (A) to which the liquid crystal alignment ability is imparted and Since both of the liquid crystal composition layers (B) can be polymerized and a covalent bond can be formed between these layers, the adhesion between these layers can be improved and the durability of the elliptically polarizing plate roll can be improved. Can be improved. Examples of the polymerizable group include a group containing a carbon-carbon double bond. Specifically, a (meth) acryloyl group, a (meth) acryloyloxy group, a (meth) acrylamide group, a vinyl group, a vinyloxy group, Examples include an azide group, a chloromethyl group, an epoxy group, and a maleimide group. Among these, since photopolymerization and thermal polymerization are relatively easy, (meth) acryloyl group, (meth) acryloyloxy group, (meth) acrylamide group, vinyl group, vinyloxy group are preferable, (meth) acryloyl group, A (meth) acryloyloxy group and a (meth) acrylamide group are more preferable. Moreover, when it is a maleimide group, it can superpose | polymerize, without using a photoinitiator.

  The polymerizable group may be directly bonded to the photo-alignable group or may be bonded via a linking group such as an alkylene group or a phenylene group. Examples of the linking group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, a decamethylene group, an undecamethylene group, and a dodecamethylene group. A linear alkylene group having 1 to 18 carbon atoms such as 1-methylethylene group, 1-methyl-trimethylene group, 2-methyl-trimethylene group, 1-methyl-tetramethylene group, 2-methyl-tetramethylene group A branched alkylene group having 1 to 18 carbon atoms such as 1-methyl-pentamethylene group, 2-methyl-pentamethylene group, 3-methyl-pentamethylene group; phenylene group such as p-phenylene group; 2 -Methoxy-1,4-phenylene group, 3-methoxy-1,4-phenylene group, 2-ethoxy-1, Alkoxy having a linear or branched alkoxyl group having 1 to 18 carbon atoms, such as -phenylene group, 3-ethoxy-1,4-phenylene group, 2,3,5-trimethoxy-1,4-phenylene group And a phenylene group. The linking group may further have an ester bond, an ether bond, an imide bond, an amide bond or a urethane bond.

  Specifically, as the photoalignable compound having a photoalignable group and a polymerizable group (hereinafter referred to as compound (I)), a compound represented by the following general formula (1) can be preferably used.

^{R 1 -X 1 -Y-X 2} -R 2 (1)
In the general formula (1), R ¹ and R ² each independently comprise a (meth) acryloyl group, a (meth) acryloyloxy group, a (meth) acrylamide group, a vinyl group, a vinyloxy group, and a maleimide group. Represents a polymerizable group selected from the group; Of these, a (meth) acryloyl group, a (meth) acryloyloxy group, or a (meth) acrylamide group is preferable because photopolymerization and thermal polymerization are relatively easy. A maleimide group is preferable because a polymerization initiator is not required.

In the general formula (1), X ¹ represents a linking group represented by-(A ¹ -B ¹ ) _m- , and X ² is represented by-(B ² -A ² ) _n-. Represents a linking group. Here, A ¹ and A ² each independently represent a single bond or a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include alkylene groups having 1 to 20 carbon atoms such as ethylene group, methylene group, propylene group, pentamethylene group and heptylene group; 3 to 3 carbon atoms such as cyclopropylene group and cyclohexylene group. 20 cycloalkylene group; arylene groups having 6 to 20 carbon atoms such as phenylene group and naphthylene group. Among these, an alkylene group is preferable and an alkylene group having 1 to 4 carbon atoms is more preferable. B ¹ and B ² each independently represent a single bond, —O—, —CO—O—, —OCO—, —CONH—, —NHCO—, —NHCO—O—, or —OCONH—. . m and n each independently represents an integer of 1 to 4. When m or n is 2 or more, a plurality of A ¹ , B ¹ , A ² and B ² may be the same or different. However, A ¹ or A ² sandwiched between ^two B ¹ or B ² is not a single bond. Specifically, when m is 2, the linking group represented by — (A ¹ —B ¹ ) _m — is —CH ₂ CH ₂ —O—CH ₂ CH ₂ CH ₂ CH ₂ —CO—O—. or represents _{-O-CH 2 CH 2 CH 2} -CO-O- and the like, when n is ^{2, - (B 2 -A 2} ) n - linking group represented by, -O-CO-Ph Represents (phenylene group) -O- (CH ₂ ) _6- and the like.

  In the general formula (1), Y represents a photoalignment group. Examples of photo-alignment groups are as described above. Among them, a group having an azobenzene skeleton, a group having a bisazo skeleton, a group having an anthraquinone skeleton, a group having a benzophenone skeleton, a group having a cinnamoyl skeleton, a chalcone A group having a skeleton or a group having a coumarin skeleton is preferable. Among such photo-alignment groups, a photo-alignment group having the following structure is preferable.

In the above formula, p _{1 to} p ₁₁ are each independently a hydrogen atom, a halogen atom, a halogenated alkyl group, a halogenated alkoxy group, a cyano group, a nitro group, an alkyl group, an alkoxy group, an aryl group, an allyloxy group, An alkoxycarbonyl group, a carboxyl group, a sulfonic acid group, an amino group, or a hydroxy group is represented. The carboxyl group and sulfonic acid group may form a salt with an alkali metal. Of the photoalignable groups represented by the above formula, a group having an azobenzene skeleton or a group having a bisazo skeleton is preferable, and a group having a bisazo skeleton represented by the following formula is particularly preferable.

In the above formula, p _{1 to} p ₄ are each independently a hydrogen atom, halogen atom, halogenated alkyl group, halogenated alkoxy group, cyano group, nitro group, alkyl group, alkoxy group, aryl group, allyloxy group, alkoxy A carbonyl group, a carboxyl group, a sulfonic acid group, an amino group, or a hydroxy group is represented. The carboxyl group and sulfonic acid group may form a salt with an alkali metal. Of these, a carboxyl group, a sulfonic acid group, an amino group, a hydroxy group, or a salt thereof is preferable, and a carboxyl group, a sulfonic acid group, or a salt thereof is preferable.

  Specific examples of the compound represented by the general formula (1) include those described in JP-A-2002-250924 and JP-A-2002-317013, and the methods described in these publications It can be easily synthesized.

  Since the compound represented by the general formula (1) has a relatively low molecular weight, the photoalignable composition layer (A) formed using the compound has excellent sensitivity to light. Therefore, liquid crystal alignment ability can be easily imparted by light irradiation. In addition, the polymerizable group of the compound has a higher degree of freedom than the polymerizable group bonded to the polymer, so the reaction rate is high, and the photoalignable composition layer (A) and liquid crystal composition provided with liquid crystal alignment ability. Since the polymerization reaction at the interface with the layer (B) can be performed satisfactorily, good adhesion at the interface is brought about.

  When the molecular weight of the compound (I) is too high, the photo-alignment group becomes difficult to move in the system, and the sensitivity to light tends to decrease. Therefore, in the present invention, the compound (I) having a molecular weight of 100 to 5000 is used. The same applies to the case where a photoalignment compound other than the compound (I) is used.

  In the case where the compound (I) is used as a photoalignment compound, the photoalignment composition further includes a compound having only a polymerizable group described later (hereinafter referred to as compound (III)) as compound (I). ) May be included as long as the photo-alignment property is not impaired. The amount of compound (III) added is preferably 10 to 95 parts by weight, more preferably 20 to 90 parts by weight, and still more preferably 20 to 50 parts by weight with respect to 100 parts by weight of compound (I).

  The photoalignment composition includes a compound having a photoalignment group but not having a polymerizable group (hereinafter referred to as compound (II)) and compound (III) instead of the compound (I). It may be a composition. Examples of the photoalignable group in compound (II) include those described above. The molecular weight of compound (II) is in the range of 100 to 5000 as described above.

  Examples of the compound (III) include (meth) acryloyl group, (meth) acryloyloxy group, (meth) acrylamide group, vinyl group, vinyloxy group, azide group, chloromethyl group, epoxy group, maleimide group and the like. The polymerizable compound which has is mentioned. Of these, silane coupling agents such as an acrylic monomer having a hydroxyl group or an ethylene glycol unit and methacrylic acid-3-trimethoxysilylpropyl ether, which have a strong hydrophilic tendency, are preferred.

  Although there is no restriction | limiting in particular in the molecular weight of compound (III), It is preferable to use a thing about 50-1000. If the molecular weight is too high, the compound (II) becomes difficult to move in the system and the sensitivity to light tends to decrease. In general, the higher the molecular weight, the better the film formability, and a smooth surface coating can be obtained.In the present invention, the surface of the photoalignable composition layer (A) is very smooth, A boundary may be formed between the liquid crystal composition layer (B) and the optical characteristics of the elliptically polarizing plate roll may be affected.

  The photoalignment composition preferably contains a suitable solvent in order to dissolve the photoalignment compound and compound (III). The solvent is not particularly limited, but glycols such as ethylene glycol, propylene glycol, dipropylene glycol monomethyl ether, alcohols such as methanol, ethanol, isopropyl alcohol, butanol, water, N-methylpyrrolidone, butyl cellosolve, phenyl cellosolve, N, N-dimethylformamide, γ-butyrolactone, dimethyl sulfoxide, toluene, tetrahydrofuran, chlorobenzene, dimethylacetamide and the like can be mentioned. The solvent is preferably selected in consideration of the coating property of the photoalignable composition, the volatilization rate of the solvent after coating, and the solvent resistance of the obliquely stretched film, and two or more types may be mixed and used. it can. In particular, when a mixed solvent composed of a mixture of butyl cellosolve and water and alcohols or glycols is used, the coating property to the obliquely stretched film is good and a uniform film can be obtained without damaging the obliquely stretched film. This is particularly preferable.

  Since the solvent is volatilized and removed after being applied to the obliquely stretched film, the total solid content concentration of the compound (I) or the compounds (II) and (III) in the photoalignment composition is 0.00. It is preferable that it is 2 weight% or more, and the range of 0.3-10 weight% is more preferable.

  Moreover, when polymerizing the photo-alignment composition layer (A) to which the liquid crystal alignment ability is imparted, the photo-alignment composition may contain a photopolymerization initiator or a thermal polymerization initiator. Specific examples of these polymerization initiators will be described later. Moreover, polymer materials, such as polyvinyl alcohol and a polyimide, can also be added to a photo-alignment composition in the range which does not impair the effect of this invention.

  Printing methods such as spin coating method, extrusion method, gravure coating method, die coating method, bar coating method, applicator method and flexo method can be used to apply the photo-alignment composition on the obliquely stretched film. A known method such as a method can be used. The obtained photoalignable composition layer (A) is usually dried.

(B) Step of imparting liquid crystal alignment ability to the photoalignable composition layer (A) In order to impart liquid crystal alignment ability to the photoalignment composition layer (A), the photoalignment group of the photoalignment compound is What is necessary is just to irradiate the polarized light of the wavelength which can be absorbed from the photo-alignment composition layer (A) side or the diagonally stretched film side perpendicularly to the surface or from an oblique direction. In addition, when the photo-alignable group is a group utilizing molecular orientation induction or isomerization reaction by the Weigert effect, the non-polarized light having a wavelength that the group efficiently absorbs is converted into a photo-alignable composition layer ( A liquid crystal alignment function may be given by irradiating the surface of the film from the A) side or the obliquely stretched film side in an oblique direction. Also, polarized light and non-polarized light may be combined. The polarized light may be either linearly polarized light or elliptically polarized light, but it is preferable to use linearly polarized light having a high extinction ratio in order to perform photoalignment efficiently.

  In order to obtain polarized light, it is necessary to use a polarizing filter, and thus there is a disadvantage that the intensity of irradiated light is reduced. Therefore, there is an advantage that a large irradiation intensity can be obtained and the irradiation time for photo-alignment can be shortened. The incident angle of non-polarized light at this time is preferably in the range of 10 ° to 80 ° with respect to the normal of the photo-alignment composition layer (A) or the obliquely stretched film surface, and the irradiation energy uniformity on the irradiated surface is obtained. In consideration of the pretilt angle, the alignment efficiency, and the like, the range of 20 ° to 60 ° is most preferable.

The wavelength of the irradiated light may be a wavelength region in which the photoalignable group has absorption. For example, when the photo-alignment group is a group having an azobenzene skeleton, ultraviolet rays having a wavelength of 350 to 500 nm that have strong absorption due to the π → π ^* transition of azobenzene are particularly preferable. Examples of the light source of the irradiation light include a xenon lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, and an ultraviolet laser such as KrF and ArF. In particular, when the photo-alignment group is a group having an azobenzene skeleton, an ultrahigh pressure mercury lamp is particularly preferable because ultraviolet light at 365 nm has a high emission intensity. Ultraviolet linearly polarized light can be obtained by passing the light from the light source through a polarizing prism such as a polarizing filter, Glan Thompson, or Glan Taylor. Moreover, it is particularly preferable that the irradiated light is substantially parallel light regardless of whether polarized light or non-polarized light is used.

(C) Step of forming liquid crystal composition layer (B) The liquid crystal composition used for forming the liquid crystal composition layer (B) contains a polymerizable liquid crystal compound. The polymerizable liquid crystalline compound means a compound having a polymerizable group exhibiting liquid crystallinity alone or a compound having a polymerizable group exhibiting liquid crystallinity in the presence of another liquid crystalline compound. The liquid crystal composition contains a polymerizable liquid crystal compound and the other liquid crystal compound. Examples of the polymerizable liquid crystal compound include, for example, Handbook of Liquid Crystals (D. Demus, JW Goodbye, GW Gray, WW Spies, V. Vill, edited by Wiley-VCH, Inc., 19). Year); Quarterly Chemical Review No. 22. Chemistry of liquid crystals (edited by the Chemical Society of Japan, 1994); JP-A-7-294735; JP-A-8-3111; JP-A-8-29618; JP-A-11-80090; JP-A-148079; JP-A-2000-178233; JP-A-2002-308831; JP-A-2002-145830, 1,4-phenylene group, 1,4-cyclohexylene group Examples thereof include a rod-like polymerizable liquid crystal compound having a rigid portion called a mesogen in which a plurality of such structures are connected and a polymerizable functional group such as a (meth) acryloyl group, a vinyloxy group, and an epoxy group.

  In addition to the above, for example, Handbook of Liquid Crystals (D. Demus, J. W. Goodby, GW Gray, H. W. Spiss, V. Vill, edited by Wiley-VCH, 1998); Quarterly Chemical Review No. 22. Chemistry of liquid crystals (edited by the Chemical Society of Japan, 1994); a discotic molecular structure formed by linking benzene rings and the like described in JP-A-07-146409, a (meth) acryloyl group, vinyloxy A discotic polymerizable compound having a polymerizable functional group such as an epoxy group or an epoxy group can also be used. Among them, a rod-like liquid crystal compound having a polymerizable group is preferable because it can easily produce a liquid crystal temperature range including a low temperature around room temperature.

  The liquid crystal composition can contain a photopolymerization initiator or a thermal polymerization initiator so that the liquid crystal composition layer (B) can be polymerized by irradiation with active energy rays or heating. However, in the case where the photoalignment composition contains a photopolymerization initiator or a thermal polymerization initiator, the liquid crystal composition does not necessarily contain a photopolymerization initiator or a thermal polymerization initiator. That is, the photopolymerization initiator or the thermal polymerization initiator may be contained in either one or both of the liquid crystal composition and the photoalignment composition. Since the interface between the photoalignable composition layer (A) and the liquid crystal composition layer (B) to which the liquid crystal alignment ability is imparted is usually in a liquid state, the radical generated by the cleavage of the polymerization initiator and the polymerization initiator is Both layers can be moved to some extent. Therefore, if it is contained in either layer, both layers can be polymerized at the same time, and both layers can be covalently bonded, and a laminated film having excellent adhesion between both layers can be obtained. In the case where the liquid crystal composition layer (B) and the photoalignable composition layer (A) are polymerized by heating, it may not be necessary to contain a polymerization initiator. Further, the thermal polymerization initiator and the photopolymerization initiator may be used in combination.

  As the photopolymerization initiator, known and conventional ones can be used. For example, 2-hydroxy-2-methyl-1-phenylpropan-1-one (such as “Darocur 1173” manufactured by Merck), 1-hydroxycyclohexyl phenyl ketone (Such as “Irgacure 184” manufactured by Ciba Specialty Chemicals), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one (such as “Darocur 1116” manufactured by Merck), 2-methyl -1-[(Methylthio) phenyl] -2-morpholinopropane-1 (such as “Irgacure 907” manufactured by Ciba Specialty Chemicals), benzylmethylketal (“Irgacure 651” manufactured by Ciba Specialty Chemicals) Etc.), 2,4-diethylthioxanthone (“Kaya” manufactured by Nippon Kayaku Co., Ltd.) A mixture of ethyl DETX "and ethyl p-dimethylaminobenzoate (such as" Kayacure EPA "manufactured by Nippon Kayaku Co., Ltd.), isopropylthioxanthone (such as" KantaCure-ITX "manufactured by Ward Prekinsop) and p-dimethyl. Examples thereof include a mixture with ethyl aminobenzoate, acylphosphine oxide (such as “Lucirin TPO” manufactured by BASF), and the like. The amount of the photopolymerization initiator used is preferably 10% by weight or less, based on the total amount of the liquid crystal composition or the photoalignable composition (the total amount when included in both compositions), preferably 0.5 to 5% % Is particularly preferred.

  As the thermal polymerization initiator, known and commonly used ones can be used. For example, methyl acetoacetate peroxide, cumene hydroperoxide, benzoyl peroxide, bis (4-t-butylcyclohexyl) peroxydicarbonate, t-butyl Peroxybenzoate, methyl ethyl ketone peroxide, 1,1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane, p-pentahydroperoxide, t-butylhydroperoxide, dicumyl peroxide, isobutyl Peroxide, di (3-methyl-3-methoxybutyl) peroxydicarbonate, organic peroxides such as 1,1-bis (t-butylperoxy) cyclohexane, 2,2′-azobisisobutyronitrile , 2,2'-azobis ( , 4-dimethylvaleronitrile), azoamidine compounds such as 2,2′-azobis (2-methyl-N-phenylpropion-amidin) dihydrochloride, 2,2′-azobis {2-methyl-N Use azoamide compounds such as [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, alkylazo compounds such as 2,2′-azobis (2,4,4-trimethylpentane), and the like. Can do. The amount of the thermal polymerization initiator used is preferably 10% by weight or less, based on the total amount of the liquid crystal composition or the photoalignable composition (the total amount when included in both compositions), preferably 0.5 to 5% % Is particularly preferred.

  The liquid crystal composition can contain a solvent. As the solvent, it is preferable to use a solvent capable of dissolving the liquid crystalline compound, and it is desirable that the solvent does not hinder the liquid crystal alignment ability of the photoalignable composition layer (A). Examples of such solvents include glycol ether esters such as propylene glycol methyl ether acetate, aromatic hydrocarbons such as toluene, xylene, mesitylene, and cymene, and esters such as methyl acetate, ethyl acetate, propyl acetate, and cyclohexyl acetate. Solvents, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ether solvents such as tetrahydrofuran, 1,2-dimethoxyethane and anisole, amides such as N, N-dimethylformamide and N-methyl-2-pyrrolidone Examples of the solvent include γ-butyrolactone and chlorobenzene. These can be used alone or in combination of two or more.

  As a method of applying the liquid crystal composition on the photo-alignable composition layer (A) to which the liquid crystal alignment ability is imparted, a spin coating method, an extrusion method, a gravure coating method, a die coating method, a bar coating method, an application Known methods such as a coating method such as a coating method and a printing method such as a flexo method can be used. The obtained liquid crystal composition layer (B) is usually dried.

  In the obtained liquid crystal composition layer (B), the liquid crystal compound takes the intended alignment state due to the effect of the liquid crystal alignment ability of the photo-alignment composition layer (A).

(D) Step of polymerizing liquid crystal composition layer (B) In this step, the liquid crystal composition layer (B) is polymerized by active energy rays such as ultraviolet rays or heating. When polymerization is performed by light irradiation, in order not to disturb the alignment state of the photoalignable composition layer (A) to which liquid crystal alignment ability is imparted, in general, a light absorption band of the photoalignable compound, For example, it is preferable to irradiate light having a wavelength other than the absorption band of the azobenzene skeleton or anthraquinone skeleton. Specifically, it is preferable to irradiate ultraviolet light of 320 nm or less, and most preferable to irradiate light having a wavelength of 250 to 300 nm. However, when the photo-alignment compound and / or liquid crystal compound causes decomposition or the like due to ultraviolet light of 320 nm or less, it may be preferable to perform the polymerization treatment with ultraviolet light of 320 nm or more.

  The irradiated light is preferably diffused light and unpolarized light so as not to disturb the alignment state of the photoalignable composition layer (A) to which liquid crystal alignment ability is imparted. Therefore, it is usually preferable to use a photopolymerization initiator having a light absorption wavelength band different from the light absorption band of the photoalignment compound. On the other hand, when light for polymerization is irradiated from the same direction as the photo-alignment operation, any wavelength can be used because there is no fear of disturbing the alignment state of the photo-alignable composition layer (A).

  On the other hand, when the polymerization is carried out by heating, it is preferably carried out at a temperature at which the polymerizable liquid crystalline compound exhibits a liquid crystal phase or at a temperature lower than that, particularly when a thermal polymerization initiator that releases radicals by heating is used. It is preferable to use one whose cleavage temperature is within the above temperature range. When the thermal polymerization initiator and the photopolymerization initiator are used in combination, the polymerization rate of the liquid crystal composition layer (B) and / or the photo-alignment composition layer (A) is increased along with the limitation of the temperature range. It is preferable to appropriately select the polymerization temperature and each initiator so as not to be different. Although the heating temperature depends on the transition temperature from the liquid crystal phase to the isotropic phase of the polymerizable liquid crystalline compound, it is preferably performed at a temperature lower than the temperature at which inhomogeneous polymerization is induced by heat. Specifically, the heating temperature is preferably 20 ° C to 300 ° C, more preferably 30 ° C to 200 ° C, and particularly preferably 30 ° C to 120 ° C. For example, when the polymerizable group is a (meth) acryloyl group, it is preferable to perform heating at a temperature lower than 90 ° C.

  As described above, in this step, it is preferable that the liquid crystal composition layer (B) and the photo-alignment composition layer (A) provided with the liquid crystal alignment ability are also polymerized. When the compound (I) or a mixture of the compound (II) and the compound (III) is used as a photoalignment compound and a polymerization initiator is contained in either or both layers, this step Both layers are polymerized and a covalent bond is formed between the two layers. Thereby, the adhesiveness of both layer interface is improved, and the elliptically polarizing plate roll excellent in durability can be obtained.

  Here, when the photopolymerization initiator is contained only in the liquid crystal composition layer (B) and the photoalignment composition layer (A) does not contain the polymerization initiator, the photoalignment composition layer (A) is included. Since there is no fear of unexpected polymerization during light irradiation for imparting liquid crystal alignment ability, the alignment operation can be performed uniformly.

  The elliptically polarizing plate roll of the present invention having the above-described configuration is excellent in display characteristics because it is thin and lightweight and can impart an appropriately controlled orientation to the optically anisotropic layer. . Further, since it can be produced without a seam, a sheet-like elliptically polarizing plate can be obtained with high yield from the elliptically polarizing plate roll. The single-piece elliptical polarizing plate cut into an arbitrary size from the elliptical polarizing plate roll of the present invention can be used as an antireflection layer in various optical products and image display devices. In general, a circularly polarizing plate is often used as the antireflection layer, but an elliptically polarizing plate may be used in order to adjust visibility such as the hue and contrast of an optical product or an image display device. Furthermore, the elliptically polarizing plate roll of the present invention can be suitably used as a raw film for producing a liquid crystal substrate roll with an elliptically polarizing plate to be described later.

<Manufacturing method of elliptical polarizing plate roll>
Next, the manufacturing method of the elliptically polarizing plate roll of this invention is described. The manufacturing method of the elliptically polarizing plate roll of this invention is used suitably as a method of producing the said elliptically polarizing plate roll of this invention. The manufacturing method of the elliptically polarizing plate roll of the present invention basically includes the following steps.
(I) a transparent protective film laminating step of laminating a transparent protective film on one surface of the polarizing film using an adhesive;
(Ii) A retardation plate laminating step in which the first retardation plate and the second retardation plate are arranged in this order on the other surface of the polarizing film using an adhesive.

(I) Transparent protective film lamination process In this process, a transparent protective film is laminated | stacked on one surface of a polarizing film using an adhesive agent. The configuration of the polarizing film, the adhesive and the transparent protective film, and the method for applying the adhesive are as described above. The adhesive may be applied to either the polarizing film or the adhesive surface of the transparent protective film, or both adhesive surfaces. Moreover, as above mentioned, after both films are bonded via an adhesive agent, a heat treatment and / or an active energy ray irradiation treatment are usually performed to cure the adhesive agent.

(Ii) Phase difference plate laminating step By this step, the first phase difference plate and the second phase difference plate are laminated in this order on the other surface of the polarizing film using an adhesive to obtain an elliptically polarizing plate roll. . This adhesive may be the same as or different from the adhesive used for pasting the transparent protective film. Hereinafter, this process will be specifically described by dividing the case where the first retardation plate is the obliquely stretched film and the case where the second retardation plate is the obliquely stretched film.

[When the first retardation plate is a diagonally stretched film]
In this case, the lamination of the two retardation plates on the polarizing film is carried out from (ii-1) the alignment film and the optically anisotropic layer on the obliquely stretched film that is the first retardation plate by the method described above. After forming a laminated film (second retardation plate) in this order to obtain a laminated body of the first retardation plate and the second retardation plate, the laminated body and the polarizing film are bonded. A method of laminating using the agent so that the obliquely stretched film side of the laminate is an adhesive surface, and (ii-2) polarizing the obliquely stretched film that is the first retardation plate using the adhesive. After bonding to the film, a laminated film (second retardation plate) composed of an alignment film and an optically anisotropic layer is formed on the surface of the obliquely stretched film opposite to the polarizing film side by the method described above. It can carry out by the method of forming in this order.

  When a laminated film is formed on a thin obliquely stretched film, film fluttering or defective defects during alignment film formation may occur, which may affect the optical characteristics of the elliptically polarizing plate. Therefore, among the above methods, the method (ii-2) of forming a laminated film on a thicker film is more preferable.

[When the second retardation plate is a diagonally stretched film]
In this case, the lamination of the two retardation plates to the polarizing film is performed by (ii-3) the alignment film and the optically anisotropic layer on the obliquely stretched film as the second retardation plate by the method described above. After forming a laminated film (first retardation plate) in this order to obtain a laminated body of the first retardation plate and the second retardation plate, the laminated body and the polarizing film are bonded. It can carry out by the method of bonding using an agent so that the optically anisotropic layer side of this laminated body may become an adhesive surface.

  Here, the bonding of the transparent protective film to the polarizing film and the first retardation plate (or the laminate of the first retardation plate and the second retardation plate) to the polarizing film are separate steps. However, from the viewpoint of simplifying the manufacturing process, it is preferable to perform both processes in parallel.

  In the manufacturing method of the elliptically polarizing plate roll of the present invention including the steps as described above, a roll-to-roll method can be suitably employed. Specifically, the method (ii-1) will be described as an example. First, a film is continuously drawn from a roll-shaped obliquely stretched film (obliquely stretched film roll), and a laminated film is formed on the film. Are formed continuously. The obliquely stretched film (laminated film of the first retardation plate and the second retardation plate) on which the laminated film is formed is continuously wound up in a roll shape (this roll-like product is referred to as a retardation plate roll). Called). When using a photo-alignment compound as the alignment film material in the formation of such a roll-to-roll laminated film, the alignment film can be continuously formed on the obliquely stretched film drawn by light irradiation. Thus, a laminated film can be formed. Next, using the retardation plate roll, the polarizing film roll, and the transparent protective film roll, the film is pulled out from these rolls, and these films are continuously bonded in this order via an adhesive. An elliptical polarizing plate roll can be obtained by continuously performing necessary processing such as curing of the film and winding up the obtained bonded body (elliptical polarizing plate) in a roll shape. The same applies to the methods (ii-2) and (ii-3). For example, in the method (ii-2), by roll-to-roll bonding, a transparent protective film, a polarizing film, an obliquely stretched film, Can be obtained by forming a laminated film continuously on the drawn film using the roll after obtaining a pasted body roll by continuously laminating the film. . By adopting such a roll-to-roll method, the manufacturing process can be greatly simplified and an adhesive can be used, so the thickness of the elliptically polarizing plate is reduced compared to the case of using an adhesive. can do.

<Liquid crystal substrate roll with elliptical polarizing plate>
The elliptically polarizing plate roll of the present invention can be suitably applied to the production of a liquid crystal substrate roll with an elliptically polarizing plate. Here, the liquid crystal substrate roll with an elliptically polarizing plate is obtained by winding a laminate of an elliptically polarizing plate having a layer structure as shown in FIG. 1 and a liquid crystal cell substrate into a roll shape. The liquid crystal cell substrate is stacked on the second retardation plate (λ / 4 plate) side of the elliptically polarizing plate.

  The liquid crystal cell substrate is one in which liquid crystal is sealed between two substrates having electrodes. As the substrate, it is preferable to use a plastic substrate because roll-to-roll bonding using an elliptically polarizing plate roll and a liquid crystal cell substrate roll becomes possible. As a plastic substrate, from the viewpoint of optical properties such as mechanical strength and transparency, a film made of a cellulose-based resin such as triacetyl cellulose or diacetyl cellulose; an acrylic resin film; a polyester resin film; a polyarylate resin film; Phon resin film; cycloolefin resin film using cycloolefin such as norbornene as a monomer. Moreover, in order to adjust the flexibility of the plastic substrate, glass fiber, filler, or the like may be added to the resin. At this time, it is preferable to match the refractive index of the additive with the refractive index of the surrounding plastic because the translucency increases.

  According to roll-to-roll bonding using an elliptically polarizing plate roll and a liquid crystal cell substrate roll, a thinned liquid crystal substrate roll with an elliptically polarizing plate can be produced efficiently and with a high yield. The liquid crystal substrate with an elliptically polarizing plate cut from the liquid crystal substrate roll with an elliptically polarizing plate can be suitably applied to a liquid crystal display device.

<Display device>
The elliptically polarizing plate roll of the present invention can be suitably applied to display devices such as a liquid crystal display device, an organic electroluminescence (organic EL) display device, and a touch panel. Examples of the liquid crystal display device include a reflective liquid crystal display device, a transflective liquid crystal display device, and a transmissive liquid crystal display device. The display device of the present invention is a display device as described above, comprising an elliptically polarizing plate cut from the elliptically polarizing plate roll and a display element. At this time, the elliptically polarizing plate is arranged so that the second retardation plate side faces the display element.

  When an elliptically polarizing plate cut from an elliptically polarizing plate roll is applied to a liquid crystal display device, in the reflective liquid crystal display device, the elliptically polarizing plate is disposed on the front side of a liquid crystal cell that is a liquid crystal display element. In the transflective liquid crystal display device and the transmissive liquid crystal display device, they are arranged on both the front side and the rear side. An adhesive can be used for bonding the liquid crystal cell and the elliptically polarizing plate, and a diffusion adhesive may be used. In addition, an optical functional layer such as a brightness enhancement film may be laminated on the elliptically polarizing plate. Examples of the brightness enhancement film include “DBEF” (trade name) sold by 3M Company (Sumitomo 3M Co., Ltd. in Japan).

  A liquid crystal cell is an element in which liquid crystal is sealed between two transparent substrates in order to switch the amount of transmitted light and has a function of changing the alignment state of the liquid crystal by applying a voltage, and is widely used in general liquid crystal display devices. It may be used. A liquid crystal cell typically has a structure including at least a pair of transparent substrates arranged opposite to each other, transparent electrodes provided on the surfaces facing each other, and a liquid crystal layer sealed between the electrodes. Have. Depending on the alignment state of the liquid crystal layer enclosed in the liquid crystal cell and the alignment state of the liquid crystal layer when a voltage is applied between the electrodes, for example, a twisted nematic (TN) mode or a vertical alignment (VA) mode is used. There are various types. As the transparent substrate, glass is usually used from the viewpoint of transparency and heat resistance, but it can also be a plastic substrate from the viewpoint of imparting flexibility.

  An organic EL display device is a display device using organic electroluminescence means in which a substance containing an organic compound is excited by receiving energy from an electric field and re-emits energy in the form of light. The organic EL display device includes, for example, an organic EL element composed of a substrate / transparent electrode (anode) / hole transport layer / light emitting layer / electron transport layer / transparent electrode (cathode) / substrate, and a positive electrode injected from the anode. Electrons injected from the hole and the cathode reach the light emitting layer through the hole transport layer and the electron transport layer, respectively, and recombine there, whereby organic molecules emit light through an excited state. The elliptically polarizing plate is disposed on the substrate on the viewing side.

  The touch panel has display means and touch input means as components. Examples of the display means include a cathode ray tube (CRT), a plasma display panel (PDP), a field emission display (FED), an inorganic electroluminescent display device, an organic electroluminescent display device, and a liquid crystal display device. The touch-type input means generally has a configuration such as a conductive film / spacer / conductive film, and the elliptically polarizing plate is disposed on the viewing-side conductive film. The touch panel is classified into a resistive touch panel, an optical touch panel, an ultrasonic touch panel, a capacitive touch panel, and the like according to the classification based on the detection method, and the elliptically polarized light of the present invention is applied to any touch panel. A board can be applied.

  By applying the elliptically polarizing plate cut from the elliptically polarizing plate roll of the present invention to a display device, various thinned display devices can be manufactured efficiently and with a high yield.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these examples. In the examples, parts and% representing the amount used or content are based on weight unless otherwise specified. The positive and negative angles are displayed with a positive (plus) in the right direction (clockwise) and a negative (minus) in the left direction (counterclockwise) around a certain axis. Moreover, the measurement and evaluation of the optical characteristics of the elliptically polarizing plate cut out from the elliptically polarizing plate roll were performed according to the following methods.

(1) Visibility-corrected transmittance Visibility-corrected transmittance is in accordance with the SEMI standard “SEMI D34-0703 FPD Polarizing Plate Measuring Method”, which is copyrighted by SEMI Japan (SEMI is an abbreviation of Semiconductor Equipment and Materials International). , Measured using a spectrophotometer “UV-2450” manufactured by Shimadzu Corporation. In the measurement, the light emitted from the light source of the spectrophotometer is polarized prism / polarizing film / retardation plate (first and second retardation plates) of the spectrophotometer so as not to be affected by the retardation plate. / The sample was set so as to proceed in the order of the light receiving part.

(2) Ellipticity The ellipticity of the elliptically polarizing plate is measured at wavelengths of 477.8 nm, 545.7 nm, and 628.6 nm using an automatic birefringence meter “KOBRA-21ADH” manufactured by Oji Scientific Instruments. did. Here, the ellipticity is the ratio of the minor axis / major axis of the ellipse constituting the elliptically polarized light. Elliptical polarization is called so because the shape of the trajectory of the light wave observed from the light propagation direction is an ellipse. Specifically, the ellipticity in the case of perfect circular polarization is 100%, the ellipticity in the case of linear polarization is 0%, and when the ellipticity is between 0% and 100%, be called.

(Production Example 1: Production of polarizing film roll)
A roll-shaped polyvinyl alcohol film having an average polymerization degree of about 2,400, a saponification degree of 99.9 mol% or more and a thickness of 75 μm is dry-type, stretched uniaxially at a stretch ratio of 5 times, The film was immersed in an aqueous solution having a weight ratio of / potassium iodide / water of 0.05 / 5/100 at 28 ° C for 60 seconds. Next, it was immersed in an aqueous solution of potassium iodide / boric acid / water at a weight ratio of 10 / 9.5 / 100 at 74 ° C. for 300 seconds. After washing with pure water at 26 ° C. for 20 seconds, it was dried at 65 ° C. to obtain a polarizing film roll in which iodine was adsorbed and oriented on polyvinyl alcohol. Its thickness was about 26 μm. The absorption axis of the polarizing film was parallel to the longitudinal direction of the roll film.

(Production Example 2: Preparation of adhesive)
A polyvinyl alcohol adhesive was prepared by dissolving 4 parts of polyvinyl alcohol having an average polymerization degree of about 1,700 and a saponification degree of 99.6 mol% or more with respect to 100 parts of water.

(Production Example 3: Preparation of photoalignable composition (A-1))
A compound having a photo-alignable group and a polymerizable group represented by the following formula (2) (molecular weight 1283.1) is dissolved in a mixed solvent composed of 2-butoxyethanol, 1-butanol, water, ethanol, A 1% solution was obtained. This solution was filtered with a filter having a pore size of 0.1 μm to obtain a photoalignment composition (A-1).

(Production Example 4: Preparation of liquid crystal composition (B-1))
With respect to 96 parts of the mixture in which the weight ratio of the liquid crystal compounds represented by the following formulas (3), (4), (5), (6), (7) is 22: 18: 33: 22: 5, -4 parts of photopolymerization initiator "Irgacure 907" manufactured by Specialty Chemicals Co., Ltd. and 100 parts of propylene glycol methyl ether acetate were mixed and dissolved, and then filtered through a filter having a pore size of 0.1 µm to obtain a liquid crystal composition (B -1). Since the liquid crystal composition after evaporation of propylene glycol methyl ether acetate from the liquid crystal composition (B-1) exhibits a liquid crystal phase at 25 ° C., in the following examples, the liquid crystal composition (B-1) is After coating and drying, an ultraviolet ray was irradiated at 25 ° C. to form an optically anisotropic layer.

<Example 1>
In this example, a λ / 2 plate made of an obliquely stretched film is bonded to a polarizing film, and further, an alignment film and an optically anisotropic layer that is a polymerization layer of a liquid crystalline compound are formed on the λ / 2 plate. A λ / 4 plate was formed to produce an elliptical polarizing plate roll.

  First, the adhesive obtained in Production Example 2 was continuously applied to both surfaces of the polarizing film drawn from the polarizing film roll obtained in Production Example 1, and one side was drawn from the roll. An obliquely stretched film (λ / 2 plate) made of a cycloolefin resin film having a slow axis in the direction of 15 ° with respect to the absorption axis of the polarizing film (longitudinal direction of the polarizing film) and a thickness of 39 μm On the surface, a 40 μm-thick triacetyl cellulose film (“KC4UY”, obtained from Konica Corporation, which has been subjected to saponification treatment on the adhesive surface in advance) is drawn out from the roll. In addition, the respective films were continuously bonded so that the longitudinal directions thereof were parallel to each other. Thereafter, the bonded body was continuously introduced into a drying furnace at 65 ° C. and dried to obtain a roll-shaped bonded body.

Next, the surface on the side of the λ / 2 plate made of an obliquely stretched film is corona-treated while pulling out the film from the bonded roll, and the photoalignable composition produced in Production Example 3 on the corona-treated surface. (A-1) was continuously formed by a micro gravure coater to form a 20 nm-thick photo-alignment composition layer (A). After drying this at 80 ° C., irradiated with polarized ultraviolet rays through a 365 nm band pass filter continuously with an intensity of 4 J / cm ² from the normal direction of the surface of the photoalignable composition layer (A), A photo-alignment composition layer (A) to which liquid crystal alignment ability was imparted was formed. At this time, the vibration direction of the irradiated polarized light was inclined by −15 ° with respect to the absorption axis of the polarizing film. Next, the liquid crystal composition (B-1) obtained in Production Example 4 was continuously applied onto the photo-alignment composition layer (A) to which the liquid crystal alignment ability was imparted using a microgravure coater, and 80 A λ / 4 plate whose slow axis is in a direction inclined by 75 ° with respect to the absorption axis of the polarizing film by being continuously irradiated with ultraviolet rays at an intensity of 640 mJ / cm ^{2 in} a nitrogen atmosphere after drying at ° C. (Laminated film of alignment film and optically anisotropic layer) was formed to obtain a broadband elliptical polarizing plate roll.

  Here, the process of cutting the film, the process of applying the composition (solution) to the film, and the process of laminating the film are each taken as one process until the final elliptical polarizing film roll is obtained from the original polarizing film roll. The number of processes was counted and used as a guide for workability and productivity. In this example, the transparent protective film and the λ / 2 plate were bonded to the polarizing film, the photo-alignment composition was applied to the λ / 2 plate, and the liquid crystal composition was applied to the alignment film. An elliptically polarizing plate roll is obtained in three steps.

<Example 2>
In this example, a λ / 4 plate composed of an alignment film and an optically anisotropic layer that is a polymerized layer of a liquid crystalline compound is formed on a λ / 2 plate composed of an obliquely stretched film, and the λ / 2 plate side A polarizing film was bonded to the substrate to produce an elliptically polarizing plate roll.

First, on an obliquely stretched film (λ / 2 plate) made of a cycloolefin-based resin film having a slow axis in the direction of 15 ° with respect to the absorption axis of the polarizing film, drawn from the roll-like material. The photo-alignment composition (A-1) produced in Production Example 3 was continuously formed by a micro gravure coater to form a 20-nm-thick photo-alignment composition layer (A). After drying this at 80 ° C., irradiated with polarized ultraviolet light through a 365 nm bandpass filter continuously at an intensity of 4 J / cm ² from the normal direction of the surface of the photoalignable composition layer (A), A photo-alignment composition layer (A) to which liquid crystal alignment ability was imparted was formed. At this time, the vibration direction of the irradiated polarized light was inclined by −15 ° with respect to the absorption axis of the polarizing film. Next, the liquid crystal composition (B-1) obtained in Production Example 4 was continuously applied onto the photo-alignment composition layer (A) to which the liquid crystal alignment ability was imparted using a microgravure coater, and 80 A λ / 4 plate whose slow axis is in a direction inclined by 75 ° with respect to the absorption axis of the polarizing film by being continuously irradiated with ultraviolet rays at an intensity of 640 mJ / cm ^{2 in} a nitrogen atmosphere after drying at ° C. A broadband λ / 4 plate roll was prepared as a (laminated film of an alignment film and an optically anisotropic layer).

  Thereafter, the adhesive obtained in Production Example 2 was continuously applied to both sides of the polarizing film drawn from the polarizing film roll obtained in Production Example 1, and on one side, from the broadband λ / 4 plate roll. The wide-band λ / 4 plate that was pulled out, with the λ / 2 plate surface facing the polarizing film side, and on the other side, a 40 μm-thick triacetylcellulose film (“KC4UY” drawn from the roll-like material was used. ", Obtained from Konica Corporation, and the saponification treatment has been applied to the adhesive surface in advance) was continuously bonded so that the longitudinal directions of the drawn films were parallel to each other. Then, the bonded body was continuously introduced into a drying furnace at 65 ° C. and dried to obtain a broadband elliptical polarizing plate roll.

  In this example, the application of the photo-alignment composition on the λ / 2 plate, the application of the liquid crystal composition on the alignment film, and the bonding of the transparent protective film and the broadband λ / 4 plate to the polarizing film, An elliptically polarizing plate roll is obtained in a total of three steps.

<Example 3>
In this example, on a λ / 4 plate made of an obliquely stretched film, a λ / 2 plate made of an optically anisotropic layer that is a polymerization layer of an alignment film and a liquid crystal compound is formed, and the λ / 2 plate side A polarizing film was bonded to the substrate to produce an elliptically polarizing plate roll.

First, on an obliquely stretched film (λ / 4 plate) made of a cycloolefin-based resin film having a slow axis in a direction of 15 ° with respect to the longitudinal direction of the film drawn from a roll-like material, The photoalignable composition (A-1) produced in Production Example 3 was continuously formed by a microgravure coater to form a photoalignable composition layer (A) having a thickness of 20 nm. After drying this at 80 ° C., irradiated with polarized ultraviolet light through a 365 nm bandpass filter continuously at an intensity of 4 J / cm ² from the normal direction of the surface of the photoalignable composition layer (A), A photo-alignment composition layer (A) to which liquid crystal alignment ability was imparted was formed. At this time, the vibration direction of the irradiated polarized light was set to a direction inclined by −15 ° with respect to the longitudinal direction of the film. Next, the liquid crystal composition (B-1) obtained in Production Example 4 was continuously applied onto the photo-alignment composition layer (A) to which the liquid crystal alignment ability was imparted using a microgravure coater, and 80 After drying at 0 ° C., a λ / 2 plate having a slow axis in a direction inclined by 75 ° with respect to the longitudinal direction of the film by continuously irradiating ultraviolet rays with an intensity of 640 mJ / cm ^{2 in} a nitrogen atmosphere ( A broadband λ / 4 plate roll was prepared as a laminated film of an alignment film and an optically anisotropic layer.

  Thereafter, the adhesive obtained in Production Example 2 was continuously applied to both sides of the polarizing film drawn from the polarizing film roll obtained in Production Example 1, and on one side, from the broadband λ / 4 plate roll. The wide-band λ / 4 plate that was pulled out, with the λ / 2 plate surface facing the polarizing film side, and on the other side, a 40 μm-thick triacetylcellulose film (“KC4UY” drawn from the roll-like material was used. ", Obtained from Konica Corporation, and the saponification treatment has been applied to the adhesive surface in advance) was continuously bonded so that the longitudinal directions of the drawn films were parallel to each other. Then, the bonded body was continuously introduced into a drying furnace at 65 ° C. and dried to obtain a broadband elliptical polarizing plate roll.

  In this example, the application of the photo-alignment composition on the λ / 4 plate, the application of the liquid crystal composition on the alignment film, and the bonding of the transparent protective film and the broadband λ / 4 plate to the polarizing film, An elliptically polarizing plate roll is obtained in a total of three steps.

<Comparative Example 1>
In this comparative example, a protective film is pasted on both sides of a polarizing film to form a polarizing plate, and a λ / 2 plate and a λ / 4 plate cut out at a predetermined angle from a longitudinally uniaxially stretched resin film are sequentially pasted on one side. In combination, an elliptically polarizing plate roll was produced by the most common method at present.

  First, the adhesive obtained in Production Example 2 was applied to both surfaces of the polarizing film drawn from the polarizing film roll obtained in Production Example 1, and the thickness of 40 μm drawn from the roll-like material was applied to both surfaces. A triacetyl cellulose film (“KC4UY”, obtained from Konica Corporation, saponified on the adhesive surface in advance) was bonded to prepare a polarizing plate with a transparent protective film. After that, a λ / 2 plate cut out at a 15 ° angle from a cycloolefin resin film previously coated with a 25 μm thick adhesive and a 75 ° angle from a cycloolefin resin film coated with another similar adhesive. The cut out λ / 4 plate was sequentially bonded onto the polarizing plate with a single sheet to prepare a broadband elliptical polarizing plate roll.

  In this comparative example, the transparent protective film is bonded to both surfaces of the polarizing film, the pressure-sensitive adhesive layer is formed on the λ / 2 plate cycloolefin resin film, and the λ / 4 plate cycloolefin resin film is adhered. Total 7 of formation of agent layer, cutting out of λ / 2 plate, cutting out of λ / 4 plate, bonding of λ / 2 plate to polarizing plate, and further bonding of λ / 4 plate to the λ / 2 plate Through the steps, an elliptically polarizing plate roll is obtained.

<Comparative example 2>
In this comparative example, a longitudinally uniaxially stretched resin film is formed on a λ / 2 plate having a slow axis in the longitudinal direction of the film, from an optically anisotropic layer that is a polymerized layer of an alignment film and a liquid crystalline compound. The resulting λ / 4 plate was formed into a broadband λ / 4 plate, cut out at a predetermined angle, and then bonded to a polarizing plate to produce an elliptical polarizing plate roll.

  First, the adhesive obtained in Production Example 2 was applied to both surfaces of the polarizing film drawn from the polarizing film roll obtained in Production Example 1, and the thickness of 40 μm drawn from the roll-like material was applied to both surfaces. A triacetyl cellulose film (“KC4UY”, obtained from Konica Corporation, saponified on the adhesive surface in advance) was bonded to prepare a polarizing plate with a transparent protective film.

On the other hand, it was produced in Production Example 3 on a film drawn from a λ / 2 plate roll made of a cycloolefin-based resin film stretched uniaxially and having a slow axis in the flow direction of the roll (longitudinal direction of the film). The photo-alignment composition (A-1) was continuously formed by a micro gravure coater to form a 20-nm-thick photo-alignment composition layer (A). After drying this at 80 ° C., irradiated with polarized ultraviolet light through a 365 nm bandpass filter continuously at an intensity of 4 J / cm ² from the normal direction of the surface of the photoalignable composition layer (A), A photo-alignment composition layer (A) to which liquid crystal alignment ability was imparted was formed. At this time, the vibration direction of the irradiation polarized light was set to a direction inclined by 150 ° with respect to the flow direction of the roll. Next, the liquid crystal composition (B-1) obtained in Production Example 4 was continuously applied onto the photo-alignment composition layer (A) to which the liquid crystal alignment ability was imparted using a microgravure coater, and 80 A λ / 4 plate having a slow axis inclined at 60 ° with respect to the flow direction of the roll by continuously irradiating ultraviolet rays with an intensity of 640 mJ / cm ^{2 in} a nitrogen atmosphere after drying at ° C. A broadband λ / 4 plate roll was prepared as a laminated film of an alignment film and an optically anisotropic layer.

  Next, after continuously applying an adhesive on the film drawn from the broadband λ / 4 plate roll, the sheet was cut at an angle of 15 ° with respect to the flow direction, and the sheet was placed on the polarizing plate with the transparent protective film. Bonding was performed to produce a broadband elliptical polarizing plate roll.

  In this comparative example, the transparent protective film is bonded to both sides of the polarizing film, the photo-alignment composition is applied onto the λ / 2 plate, the liquid crystal composition is applied onto the alignment film, and the broadband λ / 4 plate is cut out. An elliptical polarizing plate roll is obtained through a total of five steps, namely, bonding of a broadband λ / 4 plate to a polarizing plate.

<Comparative Example 3>
In this comparative example, an optically anisotropic layer λ / 2 plate, which is a polymerized layer of an alignment film and a liquid crystalline compound, is formed on a triacetylcellulose film that is a transparent protective film, and further, an alignment film and a liquid crystal are further formed thereon. A λ / 4 plate composed of an optically anisotropic layer, which is a polymerization layer of a functional compound, was formed to produce a broadband λ / 4 plate, which was bonded to a polarizing film to produce an elliptically polarizing plate roll.

The light produced in Production Example 3 on a film drawn from a roll-shaped triacetylcellulose film ("KC4UY", obtained from Konica Corporation, and the saponification treatment has been applied to the adhesive surface in advance) having a thickness of 40 μm The alignment composition (A-1) was continuously formed using a microgravure coater to form a 20 nm-thick photoalignment composition layer (A). After drying this at 80 ° C., irradiated with polarized ultraviolet rays through a 365 nm band pass filter continuously with an intensity of 4 J / cm ² from the normal direction of the surface of the photoalignable composition layer (A), A photo-alignment composition layer (A) to which liquid crystal alignment ability was imparted was formed. At this time, the vibration direction of the irradiated polarized light was inclined by 105 ° with respect to the flow direction of the roll. Next, the liquid crystal composition (B-1) obtained in Production Example 4 was continuously applied onto the photo-alignment composition layer (A) to which the liquid crystal alignment ability was imparted using a microgravure coater, and 80 After drying at 0 ° C., a λ / 2 plate in which the slow axis is inclined by 15 ° with respect to the flow direction of the roll by continuously irradiating ultraviolet rays with an intensity of 640 mJ / cm ^{2 in} a nitrogen atmosphere ( A laminated film of an alignment film and an optically anisotropic layer).

Next, the photoalignment composition (A-1) produced in Production Example 3 is continuously formed on the λ / 2 plate by a microgravure coater, and the photoalignment composition layer (A) having a thickness of 20 nm is formed. Formed. After drying this at 80 ° C., irradiated with polarized ultraviolet light through a 365 nm bandpass filter continuously at an intensity of 4 J / cm ² from the normal direction of the surface of the photoalignable composition layer (A), A photo-alignment composition layer (A) to which liquid crystal alignment ability was imparted was formed. At this time, the vibration direction of the irradiation polarized light was set to a direction inclined by −15 ° with respect to the flow direction of the roll. Next, the liquid crystal composition (B-1) obtained in Production Example 4 was continuously applied onto the photo-alignment composition layer (A) to which the liquid crystal alignment ability was imparted using a microgravure coater, and 80 After drying at 0 ° C., a λ / 4 plate having a slow axis in a direction inclined by 75 ° with respect to the flow direction of the roll by continuously irradiating ultraviolet rays with an intensity of 640 mJ / cm ^{2 in} a nitrogen atmosphere ( A broadband λ / 4 plate roll was prepared as a laminated film of an alignment film and an optically anisotropic layer.

  Thereafter, the adhesive obtained in Production Example 2 was continuously applied to both sides of the polarizing film drawn from the polarizing film roll obtained in Production Example 1, and on one side, from the broadband λ / 4 plate roll. The wide-band λ / 4 plate that was pulled out, with the triacetyl cellulose surface facing the polarizing film side, and the other surface with a 40 μm thick triacetyl cellulose film (“KC4UY”) pulled out from the roll-like material And obtained from Konica Corporation, and the saponification treatment is applied to the adhesive surface in advance), and the respective drawn films were continuously bonded so that the longitudinal directions thereof were parallel to each other. Then, the bonded body was continuously introduced into a drying furnace at 65 ° C. and dried to obtain a broadband elliptical polarizing plate roll.

  In this comparative example, application of the photo-alignment composition on the triacetyl cellulose film, application of the liquid crystal composition on the alignment film, application of the photo-alignment composition on the optically anisotropic layer, on the alignment film An elliptically polarizing plate roll was obtained through a total of five steps, namely, application of the liquid crystal composition to the substrate, and bonding of the broadband λ / 4 plate and the transparent protective film to the polarizing film.

  Table 1 shows the total thickness, suitability for processing, and presence / absence of seams for the elliptically polarizing plate rolls produced in the above Examples and Comparative Examples.

In Table 1, the meanings of symbols in each evaluation item are as follows.
Thickness A: Total thickness is 110 μm or less,
○: The total thickness exceeds 110 μm and is 150 μm or less (not shown in the table),
(Triangle | delta): Total thickness exceeds 150 micrometers, 200 micrometers or less,
X: The total thickness exceeds 200 μm.

Processability / Productivity ○: Number of processes is 3,
Δ: 4 to 6 steps
X: The number of processes is 7 or more.

Seam ○: No seam,
X: There is a seam.

  In Examples 1 to 3, an elliptically polarizing plate roll can be produced with a very small number of manufacturing steps, that is, a total of three steps including the application of the photo-alignment composition and the liquid crystal composition and the roll bonding step with the polarizing film. In addition, the obtained elliptically polarizing plate roll is thin and seamless. In particular, in Example 1, since the photo-alignment composition and the liquid crystal composition are applied to a film having a certain thickness, a λ / 4 plate composed of an alignment film and an optically anisotropic layer is better. It was possible to form with good quality. On the other hand, in Comparative Example 1, the adhesive coating process on the stretched film, the sheet cutting process and the sheet laminating process of the stretched film are each twice, so the work process is complicated and the total thickness is doubled. It was about. In Comparative Example 2, since it was necessary to bond the broadband λ / 4 plate with the polarizing plate at an angle, the roll was a seam.

  Next, a sample was cut out from the center of each elliptical polarizing plate roll, and the visibility corrected transmittance and ellipticity were measured. The results are shown in Table 2.

  In any of Examples 1 to 3, it is understood that a circularly polarizing plate having a broadband property equivalent to that of Comparative Examples 1 to 3 is obtained. As described above, according to the present invention, it is possible to form an elliptically polarizing plate roll body that is very thin as compared with the conventional elliptically polarizing plate and has no seam by a simple process, and has a conventional configuration. It can be seen that it has the same performance as that of the elliptically polarizing plate.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a cross-sectional schematic diagram which shows the example of the basic layer structure of the elliptically polarizing plate roll which concerns on this invention.

Explanation of symbols

  100a, 100b Elliptical polarizing plate roll, 101a, 101b Polarizing film, 102a, 102b Transparent protective film, 103a, 108b First retardation plate, 104a, 104b First adhesive layer, 105a, 105b Second adhesive layer 106a, 106b Alignment film, 107a, 107b Optically anisotropic layer, 108a, 103b Second retardation plate.

Claims (16)

A polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin;
A transparent protective film laminated on one surface of the polarizing film via a first adhesive layer;
A first retardation plate laminated on the other surface of the polarizing film via a second adhesive layer;
A second retardation plate laminated on the first retardation plate,
One of the first retardation plate and the second retardation plate is an obliquely stretched film formed by stretching a thermoplastic resin film in an oblique direction with respect to its width direction,
The other of the first retardation plate and the second retardation plate is composed of an alignment film and an optically anisotropic layer that is a polymerization layer of a liquid crystalline compound laminated on the alignment film. ,
The alignment film is formed by applying a composition containing a low-molecular photoalignment compound having a molecular weight in the range of 100 to 5000 having a photoalignment group that brings the alignment ability of the liquid crystalline compound by light irradiation, and the resulting coating It is formed by light irradiation to the layer,
The second retardation plate is an elliptically polarizing plate roll having a slow axis in a direction intersecting with the slow axis of the first retardation plate.   The in-plane retardation value of the first retardation plate at a wavelength of 550 nm is in a range of 250 to 290 nm, and the in-plane retardation value of the second retardation plate at a wavelength of 550 nm is in a range of 125 to 150 nm. The elliptically polarizing plate roll according to claim 1.   The angle formed by the slow axis of the first retardation plate and the absorption axis or transmission axis of the polarizing film is substantially 15 °, and the slow axis of the second retardation plate and the polarizing film The elliptically polarizing plate roll according to claim 1 or 2, wherein an angle formed by the absorption axis or the transmission axis is substantially 75 °.   The elliptically polarizing plate roll according to any one of claims 1 to 3, wherein a thickness of each of the first adhesive layer and the second adhesive layer is 1 µm or less.   The elliptically polarizing plate roll according to claim 1, wherein the obliquely stretched film has a thickness of 20 to 60 μm and is a stretched film made of a cycloolefin-based resin film.   The photoalignment compound contained in the composition forming the alignment film has a photoalignment group containing a double bond selected from the group consisting of C = C, C = N, N = N, and C = O. The elliptically polarizing plate roll in any one of Claims 1-5.   The photo-alignment group is a group having a polyene skeleton, a group having a stilbene skeleton, a group having a stilbazole skeleton, a group having a stilbazolium skeleton, a group having a cinnamoyl skeleton, a group having a hemithioindigo skeleton, a group having a chalcone skeleton, an aromatic A group having a Schiff base skeleton, a group having an aromatic hydrazone skeleton, a group having an azobenzene skeleton, a group having an azonaphthalene skeleton, a group having an aromatic heterocyclic azo skeleton, a group having a bisazo skeleton, a group having a formazan skeleton, The elliptically polarizing plate roll according to claim 6, selected from the group consisting of a group having an azoxybenzene skeleton, a group having a benzophenone skeleton, a group having a coumarin skeleton, and a group having an anthraquinone skeleton. The photo-alignment group has the following formula:

(Wherein p _{1 to} p ₄ are each independently a hydrogen atom, a halogen atom, a halogenated alkyl group, a halogenated alkoxy group, a cyano group, a nitro group, an alkyl group, an alkoxy group, an aryl group, an allyloxy group, an alkoxy group) Represents a carbonyl group, a carboxyl group, a sulfonic acid group, an amino group, or a hydroxy group.)
The elliptically polarizing plate roll according to claim 7, which has a bisazo skeleton represented by:   The elliptically polarizing plate roll according to any one of claims 6 to 8, wherein the photoalignment compound further has a polymerizable group containing a carbon-carbon double bond in addition to the photoalignment group.   The elliptically polarizing plate roll according to claim 1, wherein the liquid crystal compound is a rod-like liquid crystal compound. A protective film laminating step of laminating a transparent protective film using an adhesive on one surface of a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin;
On the other surface of the polarizing film, a retardation plate laminating step of arranging a first retardation plate and a second retardation plate in this order using an adhesive, and
One of the first retardation plate and the second retardation plate is an obliquely stretched film formed by stretching a thermoplastic resin film in an oblique direction with respect to its width direction,
The other of the first retardation plate and the second retardation plate is composed of an alignment film and an optically anisotropic layer that is a polymerization layer of a liquid crystalline compound laminated on the alignment film. ,
The alignment film is obtained by applying a composition containing a low-molecular photoalignment compound having a molecular weight in the range of 100 to 5000 having a photoalignment group that brings the alignment ability of the liquid crystalline compound by light irradiation. Formed by irradiating the coating layer with light,
When the first retardation plate is the obliquely stretched film, the retardation plate laminating step is a step of bonding one surface of the obliquely stretched film to the other surface of the polarizing film using an adhesive. And forming the alignment film and the optically anisotropic layer in this order on the other surface of the obliquely stretched film,
When the second retardation plate is the obliquely stretched film, the retardation plate laminating step, after forming the alignment film and the optically anisotropic layer in this order on one surface of the obliquely stretched film, The manufacturing method of an elliptically polarizing plate roll including the process of bonding the said optically anisotropic layer on the other surface of the said polarizing film using an adhesive agent.   In the case where the first retardation plate is the obliquely stretched film, the transparent protective film and the obliquely stretched film are bonded to the polarizing film by rolling the transparent protective film, or rolling the polarizing film. And a roll-like product of the obliquely stretched film, and simultaneously and continuously by roll-to-roll bonding, and then the alignment film on the obliquely stretched film surface of the obtained laminated film The method for producing an elliptically polarizing plate roll according to claim 11, wherein the optically anisotropic layer is formed in this order.   When the second retardation plate is the obliquely stretched film, the transparent protective film and the optically anisotropic layer are bonded to the polarizing film by rolling the transparent protective film and the polarizing film. Using a roll-like product and a roll-like product of a laminated film in which the alignment film and the optically anisotropic layer are laminated in this order on the obliquely stretched film, roll-to-roll bonding simultaneously and continuously The manufacturing method of the elliptically polarizing plate roll of Claim 11 performed automatically.   The elliptically polarizing plate roll according to claim 1 and the liquid crystal cell substrate roll are roll-to-roll pasted using the second retardation plate side of the elliptically polarizing plate roll as a bonding surface. A liquid crystal substrate roll with an elliptically polarizing plate.   An elliptically polarizing plate cut from the elliptically polarizing plate roll according to claim 1 and a display element, wherein the elliptically polarizing plate has a second retardation plate side facing the display element. Display device arranged like this.   The display device according to claim 15, wherein the display element is a liquid crystal cell or an organic EL element.

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