Optical film, polarizer, and image display device

Abstract

To provide an optical film excellent in ultraviolet absorption property and color tone, a polarizer using the optical film, an image display device using the polarizer, and an information processing apparatus including the image display device.SOLUTION: An optical film includes a polyester resin layer containing an arylic fluorene-based polyester resin and a thermoplastic acrylic resin layer containing an acrylic resin, and is produced by being drawn into a film. The polyester resin layer has a thickness ratio of 1.0-30% with respect to the whole optical film. A thickness phase difference Rth (589) at a wavelength of 589 nm is -200-0 nm. An in-plane retardation Ro (550) at wavelength of 550 nm is 50-160 nm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical film, a polarizing plate using the optical film, and an image display device including at least one of the polarizing plates. [Background technology]

[0002] Conventionally, the polarizers used in polarizing plates for image display devices are polyvinyl alcohol (PVA) resin films that are dyed with iodine or dichroic dyes and oriented by stretching. These polarizers are susceptible to the effects of ultraviolet light, moisture, and heat, and their polarization performance deteriorates due to decomposition and dimensional changes. To prevent this, a polarizer is used in which a transparent protective film is attached to one or both sides of the polarizer with an adhesive.

[0003] Triacetyl cellulose (TAC) is commonly used as a polarizer protective film because it is transparent, optically isotropic, and has excellent adhesion to PVA. Meanwhile, in recent years, as the price of LCD TVs has fallen, LCD panels are increasingly being transported in simple packaging to reduce costs. This requires durability that can withstand temperature changes and humidity during transport, and there is a growing need for polarizers with low moisture permeability. This has led to a demand for alternative materials to TAC film, which has high moisture permeability. Films made from various modified acrylic resins and polyethylene terephthalate resins with specific retardation ranges have been developed and put to practical use.

[0004] Furthermore, as LCD displays become thinner, polarizing plates are also required to become thinner, and the TAC film used in polarizing plates is also becoming thinner. However, as TAC film becomes thinner, problems arise such as a decrease in mechanical strength and moisture permeability, and there is a need for alternative materials to TAC film to address these issues.

[0005] Furthermore, a polarizer protective film is required to have scratch resistance so that the display surface of a flat panel display such as a liquid crystal display (LCD) does not deteriorate in visibility due to scratches caused during handling. For this reason, scratch resistance is generally imparted by using a hard coat film in which a hard coat layer is provided on a substrate film. However, providing a hard coat layer makes the film thicker, which makes it impossible to meet the demand for thinner films.

[0006] Furthermore, polarizer protective films contain ultraviolet absorbers to prevent deterioration of iodine in the polarizer due to ultraviolet rays. However, the content of the ultraviolet absorbers is limited by the solubility of the ultraviolet absorbers in the resin, and if the content is high, the ultraviolet absorbers will bleed. In other words, as the thickness of the polarizer protective film is reduced, it becomes difficult to incorporate an amount of ultraviolet absorber necessary to protect iodine.

[0007] For example, Patent Document 1 discloses a polarizer protective film that has high solubility of an ultraviolet absorber, and that can exhibit sufficient ultraviolet absorption ability even when the thickness of the polarizer protective film is thin, thereby preventing deterioration of iodine due to ultraviolet rays. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 7019852 Summary of the Invention [Problem to be solved by the invention]

[0009] However, it has been found that the addition of a high concentration of an ultraviolet absorber to a polarizer protective film causes a new problem of changing the color tone of the polarizer protective film, although it is preferable that the polarizer protective film does not affect the color tone of the polarizer. Therefore, a polarizer protective film that can achieve both ultraviolet absorption and color tone is desired.

[0010] The present invention has been made to solve the above-mentioned problems, and provides an optical film having excellent ultraviolet absorption properties and color tone, a polarizing plate using the optical film, an image display device using the polarizing plate, and an information processing device equipped with the image display device. [Means for solving the problem]

[0011] The present inventors have conducted extensive research to achieve the above object, and as a result have found that the above object can be achieved by using a polyester-based resin layer containing an arylated fluorene-based polyester resin, thereby completing the present invention.

[0012] That is, the present invention is as follows. [1] a polyester-based resin layer containing an arylated fluorene-based polyester resin; a thermoplastic acrylic resin layer containing an acrylic resin, An optical film formed by stretching, the thickness ratio of the polyester-based resin layer to the entire optical film is 1.0 to 30%; The thickness retardation Rth(589) at a wavelength of 589 nm is −200 to 0 nm, The in-plane retardation Ro(550) at a wavelength of 550 nm is 50 to 160 nm. Optical film. [2] The spectral transmittance at 380 nm is 10% or less. The optical film according to [1]. [3] The thickness is 10 to 90 μm. The optical film according to [1] or [2]. [4] Total light transmittance is 85% or more. [1] The optical film according to any one of [1] to [3]. [5] The arylated fluorene-based polyester resin contains a structural unit derived from a dicarboxylic acid having an arylated fluorene skeleton. [4] The optical film according to any one of [1] to [4]. [6] The thermoplastic acrylic resin layer contains rubber particles. [1] The optical film according to any one of [1] to [5]. [7] The thermoplastic acrylic resin layer is coated with a modifier having a weight average molecular weight of 1.0×10 5 Contains 0-5% of the above acrylic resins, [6] The optical film according to any one of [1] to [6]. [8] a three-layer structure in which the polyester-based resin layer is positioned as an intermediate layer and the thermoplastic acrylic resin layer is positioned as an outermost layer, or a three-layer structure in which two of the polyester-based resin layers are laminated together with the thermoplastic acrylic resin layer interposed therebetween, so that the polyester-based resin layer is positioned as an outermost layer and the thermoplastic acrylic resin layer is positioned as an intermediate layer; [1] The optical film according to any one of [1] to [7]. [9] The content of the ultraviolet absorber in the polyester resin layer is 1% by mass or less. [1] The optical film according to any one of [1] to [8].

[10] The surface has one or more layers selected from an easy-adhesion layer, a hard coat layer, an anti-glare layer, an anti-reflection layer, a low-reflection layer, an anti-fouling layer, and an anti-fingerprint layer. [1] The optical film according to any one of [1] to [9].

[11] Used as a polarizer protective film, [1] The optical film according to any one of [1] to

[10] .

[12] a polarizer protective film; A retardation film; a polarizer positioned between the polarizer protective film and the retardation film, The polarizer protective film is the optical film according to

[11] . Polarizing plate.

[13]

[12] The polarizing plate according to

[12] is provided. Image display device.

[14] It is possible to change the shape, The image display device according to

[13] .

[15] It is for automotive use, The image display device according to

[13] or

[14] .

[16]

[13] to

[15] , comprising the image display device according to any one of

[13] to

[15] . Information processing device. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide an optical film having excellent ultraviolet absorption properties and color tone, a polarizing plate using the optical film, an image display device using the polarizing plate, and an information processing device including the image display device. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view schematically illustrating a polarizer protective film according to an embodiment of the present invention. [Figure 2A] 1 is a cross-sectional view schematically illustrating a polarizing plate according to an embodiment of the present invention. [Figure 2B] FIG. 10 is a cross-sectional view schematically illustrating a polarizing plate according to another embodiment of the present invention. [Figure 3A] 1 is a cross-sectional view schematically illustrating an image display device (OLED) according to one embodiment of the present invention. [Figure 3B] 1 is a cross-sectional view schematically illustrating an image display device (LCD) according to an embodiment of the present invention. [Figure 4] 1 is a cross-sectional view schematically illustrating a rollable display according to an embodiment of the present invention. [Figure 5] 1 is a perspective view schematically illustrating an information processing apparatus according to an embodiment of the present invention; [Figure 6] 1 is a perspective view schematically illustrating a foldable smartphone according to an embodiment of the present invention; [Figure 7]1 is a perspective view schematically illustrating a rollable smartphone according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail with reference to the drawings as necessary, but the present invention is not limited to this, and various modifications are possible without departing from the spirit of the present invention. In the drawings, the same elements are given the same reference numerals, and redundant explanations will be omitted. Furthermore, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[0016] 1. Optical film The optical film of this embodiment has a polyester resin layer containing an arylated fluorene polyester resin and a thermoplastic acrylic resin layer containing an acrylic resin, and is formed by stretching the layers. The thickness ratio of the polyester resin layer to the entire optical film is 1 to 30%, the thickness retardation Rth(589) at a wavelength of 589 nm is −200 to 0 nm, and the in-plane retardation Ro(550) at a wavelength of 550 nm is 50 to 160 nm.

[0017] In this embodiment, by using an arylated fluorene polyester resin, it is possible to impart ultraviolet absorption to the polyester resin layer. Therefore, it is possible to suppress the addition of an ultraviolet absorber, and thus to suppress the change in color tone of the optical film caused by the addition of an ultraviolet absorber. In the following, near transparency is considered to be excellent in color tone.

[0018] Furthermore, the optical film of this embodiment has a thermoplastic acrylic resin layer that is transparent and scratch-resistant, thereby achieving superior mechanical strength. Furthermore, by forming a multilayer film by laminating a thermoplastic acrylic resin layer and a polyester resin layer, the optical film has excellent durability and mechanical strength, as well as excellent flexibility. Furthermore, when the optical film is used as a polarizer protective film, it has low moisture permeability and thermal stability, making it possible to prevent deterioration of the polarizer due to moisture and heat.

[0019] Furthermore, the optical film of this embodiment has a predetermined thickness retardation Rth(589) and a predetermined in-plane retardation Ro(550), and therefore can be suitably used as a polarizer protective film for protecting a polarizer.

[0020] Specifically, light emitted from image display devices such as liquid crystal displays (LCDs) and organic electroluminescence (EL) displays passes through a polarizer and is therefore often linearly polarized. When such emitted light is viewed through polarized sunglasses, the emitted linearly polarized light is perpendicular to the polarized sunglasses, which can reduce the visibility of the image. Hereinafter, when we simply refer to "visibility," we mean the visibility of an image when the image display device is viewed through polarized sunglasses.

[0021] In contrast, the optical film of this embodiment contains an arylated fluorene-based polyester resin, which tends to have a relatively high in-plane retardation Ro(550). Therefore, by using the optical film of this embodiment as a polarizer protective film, light emitted from an image display device can be circularly polarized, resulting in excellent visibility.

[0022] Another method for preventing image visibility from being reduced even when viewing images using polarized sunglasses or the like is to attach a film with a λ / 4 phase difference to the viewing side of the polarizer protective film located on the outer side of the polarizer. This results in circularly polarized light, making it difficult to reduce image visibility even when viewing images using polarized sunglasses. However, since this method requires more layers than a typical polarizing plate, it is not suitable for achieving a thinner film. Furthermore, the additional layers increase the number of manufacturing steps and the manufacturing cost. Therefore, from this perspective, it is preferable to use the optical film of this embodiment as a polarizer protective film.

[0023] In this embodiment, the "polarizer protective film" refers to a film used for the purpose of protecting a polarizer from the external environment, and is laminated directly onto a polarizer or indirectly via a retardation film or the like.

[0024] The optical film of this embodiment may be a stretched film or an unstretched film, but is preferably a stretched film. Such a stretched film allows for a thinner film. In addition, stretching allows the thickness retardation Rth(589) and in-plane retardation Ro(550) to be adjusted within a predetermined range, improving the ability to circularly polarize light emitted from an image display device. When used as a polarizer protective film, the visibility of images viewed through polarized sunglasses or the like tends to be improved.

[0025] The multilayer structure of the optical film is not particularly limited, and examples thereof include a two-layer structure consisting of a polyester-based resin layer and a thermoplastic acrylic resin layer; a three-layer structure in which a polyester-based resin layer is located as an intermediate layer and a thermoplastic acrylic resin layer is located as an outermost layer; a three-layer structure in which a polyester-based resin layer is located as an outermost layer and a thermoplastic acrylic resin layer is located as an intermediate layer; a three-layer structure in which a polyester-based resin layer is located as one outermost layer and a thermoplastic acrylic resin layer is located as an intermediate layer and as the other outermost layer; and any four-layer or more structure having a thermoplastic acrylic resin layer and a thermoplastic acrylic resin layer.

[0026] In this embodiment, the thermoplastic acrylic resin layer is preferably not an adhesive layer. More specifically, the optical film is preferably a multilayer film having a thermoplastic acrylic resin layer containing an acrylic resin and formed by stretching.

[0027] Among these, a three-layer structure in which a polyester-based resin layer is positioned as an intermediate layer and a thermoplastic acrylic resin layer is positioned as an outermost layer, or a three-layer structure in which two polyester-based resin layers are laminated with a thermoplastic acrylic resin layer interposed therebetween, with a polyester-based resin layer positioned as an outermost layer and a thermoplastic acrylic resin layer positioned as an intermediate layer, is preferred, and a three-layer structure in which a polyester-based resin layer is positioned as an intermediate layer and a thermoplastic acrylic resin layer is positioned as an outermost layer is more preferred, which tends to further improve surface hardness and flexibility.

[0028] Fig. 1 is a cross-sectional view schematically illustrating a polarizer protective film according to one embodiment of the present invention. As shown in Fig. 1, the film has a three-layer structure in which a polyester-based resin layer 11 is positioned as an intermediate layer and a thermoplastic acrylic-based resin layer 12 is positioned as an outermost layer, which tends to further improve scratch resistance and reduce surface reflectance. Furthermore, by forming such a laminate, the acrylic resin is less likely to crack, allowing the optical film to be made thinner. Furthermore, the arylated fluorene-based polyester resin has excellent ultraviolet absorption ability, making it possible to achieve both high ultraviolet absorption performance, a nearly transparent color tone, and a thin film.

[0029] The layers of the optical film may be bonded via an adhesive layer, or may be in contact with each other without a layer intended for adhesion. Among these, it is preferable that the polyester resin layer and other layers, such as the thermoplastic acrylic resin layer described below, are in contact with each other without a layer intended for adhesion. Since the polyester resin layer can be laminated with the thermoplastic acrylic resin layer with good adhesion, it is possible to omit a layer intended for adhesion. This allows the optical film to be made thinner.

[0030] The optical film has a thickness retardation Rth(589) at a wavelength of 589 nm of −200 to 0 nm, preferably −175 to −10 nm, −150 to −25 nm, −125 to −30 nm, or −100 to −40 nm. When the thickness retardation Rth(589) is within the above range, visibility tends to be further improved.

[0031] The optical film has an in-plane retardation Ro(550) at a wavelength of 550 nm of 50 to 160 nm, preferably 100 to 155 nm, 120 to 150 nm, or 135 to 145 nm. When the in-plane retardation Ro(550) is within the above range, visibility tends to be further improved.

[0032] The thickness retardation Rth(589) and the in-plane retardation Ro(550) can be adjusted by the amount of the arylated fluorene-based polyester resin used, the content of the structural unit having an arylated fluorene skeleton in the arylated fluorene-based polyester resin, and the stretching conditions, such as the stretching ratio and stretching temperature, when producing the optical film.

[0033] The spectral transmittance of the optical film at 380 nm is preferably 10% or less, 7% or less, 5% or less, 3% or less, or 1% or less. The lower limit of the spectral transmittance at 380 nm is not particularly limited, but a lower limit is preferable, and it may be 0%. When the spectral transmittance at 380 nm is within the above range, ultraviolet absorption tends to be further improved.

[0034] The spectral transmittance at 380 nm can be adjusted by the amount of the arylated fluorene polyester resin used and the content of the structural unit having an arylated fluorene skeleton in the arylated fluorene polyester resin.

[0035] The thickness of the optical film is preferably 10 to 90 μm, 20 to 80 μm, 25 to 70 μm, or 30 to 65 μm. When the thickness is within the above range, flexibility is further improved and the color tone tends to be excellent. The thickness of the optical film can be adjusted by the stretching ratio, etc.

[0036] The total light transmittance of the optical film is preferably 80% or more, 83 to 95%, or 85 to 93%. When the total light transmittance is within the above range, the transparency of the optical film tends to be further improved.

[0037] The total light transmittance of the optical film may be adjusted by the composition of the polyester resin layer or the thermoplastic acrylic resin layer, as well as the stretching conditions such as the stretching ratio and stretching temperature when producing the optical film, the thickness of the optical film, and the like.

[0038] The structure of each layer will be described in detail below.

[0039] 1.1.Polyester resin layer The polyester-based resin layer contains an arylated fluorene-based polyester resin (hereinafter also simply referred to as "polyester resin"), and may contain an ultraviolet absorber and other additives as necessary.

[0040] The thickness ratio of the polyester-based resin layer to the entire optical film is 1.0 to 30%, preferably 2.5 to 25%, and more preferably 5.0 to 20%. When the thickness ratio of the polyester-based resin layer is within the above range, ultraviolet absorption and visibility are further improved, and color tone tends to be more excellent.

[0041] The thickness of the polyester-based resin layer is preferably 1 to 30 μm, 5 to 25 μm, or 7 to 20 μm. When the thickness of the polyester-based resin layer is within the above range, ultraviolet absorption and visibility are further improved, and the color tone tends to be more excellent.

[0042] The glass transition temperature of the arylated fluorene polyester resin is preferably 105 to 155°C, 110 to 150°C, 115 to 145°C, or 120 to 140°C. When the glass transition temperature is within the above range, retardation expression tends to be further improved. The glass transition temperature can be measured by the method described in the examples below.

[0043] The weight average molecular weight of the arylated fluorene polyester resin is 2.0 × 10 4 ~2.0×10 5 is 3.0 × 10 4 ~1.5×10 5 is 4.0 × 10 4 ~1.0×10 5 When the weight average molecular weight is within the above range, the flex resistance and mechanical strength tend to be further improved.

[0044] The arylated fluorene-based polyester resin is not particularly limited, but examples thereof include a polyester containing, as structural units, a dicarboxylic acid having an arylated fluorene skeleton and an arbitrary diol, a polyester containing, as structural units, an arbitrary dicarboxylic acid and a diol having an arylated fluorene skeleton, and a polyester containing, as structural units, a dicarboxylic acid having an arylated fluorene skeleton and a diol having an arylated fluorene skeleton.

[0045] Among these, it is preferable that the arylated fluorene-based polyester resin contains a structural unit derived from a dicarboxylic acid having an arylated fluorene skeleton, which tends to further improve ultraviolet absorption and visibility and to provide a more excellent color tone.

[0046] 1.1.2.1. Dicarboxylic acids The dicarboxylic acid is not particularly limited, but examples thereof include dicarboxylic acids having a fluorene skeleton and dicarboxylic acids not having a fluorene skeleton. The dicarboxylic acids may be used alone or in combination of two or more.

[0047] The dicarboxylic acid having a fluorene skeleton is not particularly limited, but examples thereof include a compound represented by the following general formula (1) or an ester thereof. [ka] (In the formula, R 1a and R 1b each independently represents an aryl group; each k independently represents an integer of 0 to 4; X 1 each independently represents an alkylene group having 1 to 8 carbon atoms.

[0048] In the above general formula (1), the group R 1a , R 1b The substitution positions of the aryl group represented by the following formula (I) on the fluorene ring are not particularly limited, but are preferably the 2-position and / or the 7-position. The aryl group is not particularly limited, but examples thereof include a phenyl group, a 1-naphthyl group, and a 2-naphthyl group.

[0049] base R 1a and R 1b The number of substitutions k is an integer of 0 to 4, and may be, for example, 0, 1, or 1 to 3.

[0050] X 1 The alkylene group having 1 to 8 carbon atoms represented by the formula (I) is not particularly limited, and examples thereof include a methylene group, an ethylene group, a trimethylene group, a propylene group, a 2-ethylethylene group, a 2-methylpropane-1,3-diyl group, etc. Among these, an alkylene group having 1 to 4 carbon atoms such as a methylene group, an ethylene group, a trimethylene group, a propylene group, or a 2-methylpropane-1,3-diyl group is preferred.

[0051] Representative compounds represented by general formula (1) are not particularly limited, but include, for example, 9,9-bis(2-carboxyethyl)fluorene (FDP-m), 9,9-bis(2-carboxypropyl)fluorene, 9,9-bis(carboxy C 4-6alkyl)fluorene, 9,9-bis(2-carboxyethyl)2,7-diphenylfluorene, 9,9-bis(2-carboxypropyl)2,7-diphenylfluorene, 9,9-bis(carboxy C 4-6 alkyl)2,7-diphenylfluorene, 9,9-bis(2-carboxyethyl)2,7-di(2-naphthyl)fluorene (DNFDP-m), 9,9-bis(2-carboxypropyl)2,7-di(2-naphthyl)fluorene, 9,9-bis(carboxyC 4-6 alkyl)2,7-di(2-naphthyl)fluorene, 9,9-bis(2-carboxyethyl)2,7-di(1-naphthyl)fluorene, 9,9-bis(2-carboxypropyl)2,7-di(1-naphthyl)fluorene, 9,9-bis(carboxy C 4-6 and 2,7-di(1-naphthyl)fluorene.

[0052] Among these, it is preferable to include a structural unit derived from a dicarboxylic acid having an arylated fluorene skeleton, such as 9,9-bis(2-carboxyethyl)2,7-di(2-naphthyl)fluorene (DNFDP-m), which tends to further improve UV absorption and visibility and provide better color tone.

[0053] The content of the structural units derived from dicarboxylic acid having a fluorene skeleton may be 50 to 100 mol%, 60 to 100 mol%, 70 to 100 mol%, 80 to 100 mol%, or 90 to 100 mol%, based on the total structural units of the dicarboxylic acid. When the content of dicarboxylic acid having a fluorene skeleton is within the above range, ultraviolet absorbency and visibility are further improved, and the color tone tends to be more excellent.

[0054] The content of the structural units derived from dicarboxylic acid having an arylated fluorene skeleton may be 50 to 80 mol %, 55 to 75 mol %, or 60 to 70 mol % relative to the total structural units of the dicarboxylic acid. When the content of dicarboxylic acid having a fluorene skeleton is within the above range, ultraviolet absorption and visibility are further improved, and color tone tends to be more excellent.

[0055] The dicarboxylic acid having no fluorene skeleton is not particularly limited as long as it does not have a fluorene skeleton, and examples thereof include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids.

[0056] The aliphatic dicarboxylic acid is not particularly limited, but examples thereof include saturated aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and decanedicarboxylic acid; and unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid.

[0057] The alicyclic dicarboxylic acid component is not particularly limited, but examples thereof include cycloalkane dicarboxylic acids such as 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, decalin dicarboxylic acid, norbornane dicarboxylic acid, adamantane dicarboxylic acid, and tricyclodecane dicarboxylic acid; and cycloalkene dicarboxylic acids such as cyclohexene dicarboxylic acid and norbornene dicarboxylic acid.

[0058] The aromatic dicarboxylic acid component is not particularly limited, and examples thereof include monocyclic aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and 4-methylisophthalic acid; condensed polycyclic aromatic dicarboxylic acids such as 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, anthracenedicarboxylic acid, and phenanthrenedicarboxylic acid; and non-condensed polycyclic aromatic dicarboxylic acids such as arylarene dicarboxylic acids such as 2,2'-biphenyldicarboxylic acid and 4,4'-biphenyldicarboxylic acid, diarylalkane dicarboxylic acids such as 4,4'-diphenylmethanedicarboxylic acid, and diaryl ketone dicarboxylic acids such as 4,4'-diphenylketone dicarboxylic acid.

[0059] The content of the structural units derived from dicarboxylic acid having no fluorene skeleton is 0 to 50 mol%, 0 to 40 mol%, 0 to 30 mol%, 0 to 20 mol%, or 0 to 10 mol%, relative to all the structural units of dicarboxylic acid. When the content of dicarboxylic acid having no fluorene skeleton is within the above range, ultraviolet absorbency and visibility are further improved, and color tone tends to be more excellent.

[0060] 1.1.2.2. Diol The diol is not particularly limited, but examples thereof include diols having a fluorene skeleton and diols not having a fluorene skeleton. The diols may be used alone or in combination of two or more.

[0061] The diol having a fluorene skeleton is not particularly limited, but examples thereof include compounds represented by the following general formula (2) or (3). [ka] (wherein each Z independently represents a phenylene group or a naphthylene group; R 2a and R 2b each independently represents an inert substituent in the reaction; each p independently represents an integer of 0 to 4; R 3 each independently represents an alkyl group, an alkoxy group, a cycloalkyloxy group, an aryloxy group, an aralkyloxy group, an aryl group, a cycloalkyl group, an aralkyl group, a halogen atom, a nitro group, or a cyano group; each q independently represents an integer of 0 to 2; R 4 each independently represents an alkylene group having 2 to 6 carbon atoms, and each r independently represents an integer of 1 or greater.

[0062] In the general formula (2), the group R 2a and R 2b Examples of the R group include, but are not limited to, alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, and t-butyl; aryl groups such as phenyl and naphthyl; cyano; and halogen atoms. 2a and R2b The substitution position may be, for example, the 2-position, the 7-position, or the 2- and 7-positions of the fluorene. In this embodiment, "inert to the reaction" means inert to the polymerization reaction of the polyester.

[0063] The number of substitutions p is an integer of 0 to 4, and may be 0 to 2, preferably 0 or 1, and particularly 0.

[0064] In the general formula (2), the substituent R 3 is not particularly limited, and examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, and t-butyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; alkoxy groups such as methoxy and ethoxy; and cycloalkyloxy groups such as cyclohexyloxy. aryloxy groups such as a phenoxy group; aralkyloxy groups such as a benzyloxy group; halogen atoms such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom; a nitro group; and a cyano group.

[0065] Among these, the group R 3 Examples of the alkyl group include an alkyl group (an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, and particularly a methyl group), an alkoxy group (an alkoxy group having 1 to 4 carbon atoms, etc.), a cycloalkyl group (C 5-8 cycloalkyl groups, aryl groups (phenyl groups, etc.) 6-12 aryl group) and the like are preferred.

[0066] The number of substitutions q is an integer of 0 to 4, and may be 0 to 3, and preferably 0 to 2, or 0 or 1.

[0067] In the general formula (2), the group R 4is not particularly limited, and examples thereof include linear or branched alkylene groups having 2 to 6 carbon atoms, such as an ethylene group, a propylene group (1,2-propanediyl group), a trimethylene group, a 1,2-butanediyl group, and a tetramethylene group.

[0068] The number of repetitions r may be 1 or more, for example, 1 to 12, 1 to 8, 1 to 5, 1 to 4, 1 to 3, or 1 or 2.

[0069] The diol represented by general formula (2) is not particularly limited, but for example, representative diol components (A) include 9,9-bis(hydroxy(poly)alkoxyphenyl)fluorenes, 9,9-bis(hydroxy(poly)alkoxynaphthyl)fluorenes, and the like.

[0070] The 9,9-bis(hydroxy(poly)alkoxyphenyl)fluorenes are not particularly limited, but examples thereof include (i) 9,9-bis(hydroxy C) such as 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (BPEF) and 9,9-bis[4-(2-hydroxypropoxy)phenyl]fluorene. 2-4 (ii) 9,9-bis(hydroxy C such as 9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isopropylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isobutylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-t-butylphenyl)fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-dimethylphenyl]fluorene, and 9,9-bis(4-(2-hydroxyethoxy)-3-t-butyl-5-methylphenyl)fluorene. 2-4 Alkoxy-mono or di C 1-4 (iii) 9,9-bis(hydroxy C, alkylphenyl)fluorene, such as 9,9-bis(4-(2-hydroxyethoxy)-3-cyclohexylphenyl)fluorene; 2-4 Alkoxy C 5-10(iv) 9,9-bis(hydroxy C such as 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene and 9,9-bis[4-(2-hydroxypropoxy)-3-phenylphenyl]fluorene 2-4 Alkoxy C 6-10 arylphenyl)fluorene, etc.; compounds in which r is 2 to 5 in the above compounds (ii) to (iv), such as 9,9-bis(hydroxy C 2-4 Alkoxy C 2-4 Alkoxyphenyl)fluorene, 9,9-bis(hydroxy C 2-4 Alkoxy C 2-4 Alkoxy-mono or di-C1-C4 alkylphenyl)fluorene, 9,9-bis(hydroxy C 2-4 Alkoxy C 2-4 Alkoxy C 6-10 arylphenyl)fluorene and the like.

[0071] The 9,9-bis(hydroxy(poly)alkoxynaphthyl)fluorenes are not particularly limited, and examples thereof include 9,9-bis(hydroxyalkoxynaphthyl)fluorenes such as 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene, 9,9-bis[5-(2-hydroxyethoxy)-1-naphthyl]fluorene, and 9,9-bis[6-(2-hydroxypropoxy)-2-naphthyl]fluorene; compounds in which r is 2 to 5, such as 9,9-bis(hydroxyC 2-4 Alkoxy C 2-4 Alkoxynaphthyl)fluorenes and the like.

[0072] The content of the structural units derived from the diol represented by general formula (2) is preferably 15 to 95 mol%, 20 to 90 mol%, 30 to 90 mol%, 45 to 90 mol%, or 60 to 90 mol%, relative to the total amount of diol components contained in the resin. When the content of the structural units derived from the diol represented by general formula (2) is within the above range, ultraviolet absorbency and visibility are further improved, color tone is more excellent, and the glass transition temperature tends to be further improved.

[0073] [ka] (In the formula, R 5a and R 5b each independently represents a substituent inert to the reaction; each m independently represents an integer of 0 to 4; X 2 each independently represents an alkylene group having 1 to 8 carbon atoms.

[0074] In the general formula (3), the group R 5a and R 5b , m is R in the general formula (2), including preferred embodiments. 2a and R 2b , p can be mentioned. Also, X 2 is X in the general formula (1), including preferred embodiments. 1 The same can be mentioned.

[0075] The diol represented by the general formula (3) is not particularly limited, but examples thereof include 9,9-bis(hydroxymethyl)fluorene, 9,9-bis(2-hydroxyethyl)fluorene, 9,9-bis(hydroxy C 3-6 Among these, 9,9-bis(hydroxymethyl)fluorene is preferred.

[0076] The content of the constitutional unit derived from the diol represented by general formula (3) is preferably 15 to 95 mol%, 20 to 90 mol%, 30 to 90 mol%, 45 to 90 mol%, or 60 to 90 mol%, relative to the total amount of diol components contained in the resin. When the content of the constitutional unit derived from the diol represented by general formula (3) is within the above range, ultraviolet absorbency and visibility are further improved, color tone is more excellent, and the glass transition temperature tends to be further improved.

[0077] The content of the structural units derived from diols having a fluorene skeleton is preferably 15 to 95 mol%, 20 to 90 mol%, 30 to 90 mol%, 45 to 85 mol%, or 60 to 80 mol%, relative to the total amount of diol components contained in the resin. When the content of the structural units derived from diols having a fluorene skeleton is within the above range, UV absorption and visibility are further improved, color tone is more excellent, and the glass transition temperature tends to be further improved.

[0078] The diol not having a fluorene skeleton is not particularly limited as long as it does not have a fluorene skeleton, and examples thereof include aliphatic diols, alicyclic diols, and aromatic diols.

[0079] The aliphatic diol is not particularly limited, but examples thereof include alkanediols such as ethylene glycol (EG), 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, neopentyl glycol, and 1,6-hexanediol; di- or tri-C diols such as ethylene glycol, dipropylene glycol, and triethylene glycol; 2-4 Examples of suitable alkanediols include polyalkanediols such as alkanediols.

[0080] The alicyclic diol is not particularly limited, but examples thereof include cyclohexanediol, cyclohexanedimethanol, and isosorbide.

[0081] Examples of aromatic diols include dihydroxyarenes such as hydroquinone and resorcinol; biphenols; bisphenols such as bisphenol A; alkylene oxide adducts of bisphenols; and di(hydroxyalkyl)arenes such as 1,3-benzenedimethanol and 1,4-benzenedimethanol.

[0082] Among these, aliphatic diols are preferred, and alkanediols having 2 to 4 carbon atoms are more preferred.

[0083] The content of the structural units derived from diols having no fluorene skeleton is preferably 5 to 85 mol%, 10 to 80 mol%, 10 to 70 mol%, 15 to 55 mol%, or 20 to 40 mol%, relative to the total amount of diols contained in the resin. When the content of the structural units derived from diols having no fluorene skeleton is within the above range, ultraviolet absorbency and visibility are further improved, color tone is more excellent, and the glass transition temperature tends to be further improved.

[0084] 1.1.3.Ultraviolet absorbers The polyester resin layer may contain an ultraviolet absorber, which can block ultraviolet rays with wavelengths of 380 nm or less, and when iodine is used in the polarizer described below, can suppress absorption of ultraviolet rays by iodine.

[0085] In addition, polyester-based resins have high solubility of ultraviolet absorbers, so even if the ultraviolet absorber is contained at a high concentration, it does not bleed out, making it possible to make the film thinner. Therefore, it is preferable that the polyester-based resin layer contains an ultraviolet absorber. However, this does not prevent other resin layers from containing an ultraviolet absorber, and the other resin layers may contain an ultraviolet absorber.

[0086] The ultraviolet absorber is not particularly limited, but known ultraviolet absorbers such as benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and triazine-based ultraviolet absorbers can be used.

[0087] The benzophenone-based ultraviolet absorber is not particularly limited, but examples thereof include 2-hydroxy-4-pentyloxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 2-hydroxy-4-octyloxy-4'-methoxybenzophenone, 2-hydroxy-4-cyclohexyloxybenzophenone, 2-hydroxy-4-octyloxy-4'-chlorobenzophenone, etc. Among these, 2-hydroxy-4-octyloxybenzophenone is preferred.

[0088] The benzotriazole-based ultraviolet absorber is not particularly limited, but examples thereof include phenol, 2-(2H-benzotriazol-2-yl)-4-methyl, phenol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl), phenol, 2-(5-chloro-2H-benzotriazol-2-yl)-6-(1,1-dimethylethyl)4-methyl, phenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl), phenol, 2, 2'-Methylene-bis(6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl), phenol, 2-(2H-benzotriazol-2-yl)-4-methyl-6-dodecyl, 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole, benzenepropanoic acid, 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy-C7-C9 alkyl ester, 2-(2H-benzotriazol-2-yl)-4,6-bis(1 -phenylethyl)phenol, 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol], 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-[(2H-benzotriazol-2-yl)phenol], 2-(2-hydroxy-3-α-cumyl-5-alkylphenyl) Examples of suitable phenols include 2,2'-methylene-bis(6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, octyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate, and 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate. Among these, phenol, 2,2'-methylene-bis(6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol is preferred.

[0089] Examples of triazine-based ultraviolet absorbers include 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4dimethylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-butyloxyphenyl)-6-(2,4-bis-butyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine, and phenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-hexyloxy. Among these, 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4dimethylphenyl)-1,3,5-triazine is preferred.

[0090] These ultraviolet absorbers may be used alone or in combination of two or more. Among these, ultraviolet absorbers having a maximum absorption wavelength in the range of 320 to 400 nm are preferred. The higher the molar extinction coefficient at 380 nm, the smaller the amount to be added, which is preferable. However, it is also preferable to select an ultraviolet absorber taking into consideration coloration due to absorption around 400 nm.

[0091] The amount of the ultraviolet absorber added is, for example, preferably 0.1 to 30 mass %, 1 to 20 mass %, or 3.0 to 15 mass % relative to the corresponding polyester resin layer. When the amount of the ultraviolet absorber added is within the above range, ultraviolet absorption performance is further improved, and the film tends to be more transparent, less colored, and more durable.

[0092] 1.1.4. Other Additives The polyester resin layer may contain various additives other than the ultraviolet absorber, if necessary, including, but not limited to, an antistatic agent, a light stabilizer, a flame retardant, a heat stabilizer, an antioxidant, an antigelling agent, a surfactant, etc.

[0093] The total content of these additives is preferably 30 parts by mass or less, 0.1 to 20 parts by mass, or 1 to 10 parts by mass relative to 100 parts by mass of the polyester resin layer.

[0094] 1.1.5. Resin manufacturing method The method for producing the polyester is not particularly limited, but for example, the polyester can be prepared by a polymerization reaction of a diol and a dicarboxylic acid. Hereinafter, the method for producing the polyester will be described as an example, but the method for producing the resin of the present embodiment is not limited to the method described below.

[0095] The polyester polymerization method is not particularly limited, but examples thereof include melt polymerization methods such as transesterification and direct polymerization, solution polymerization, and interfacial polymerization. These polymerization reactions may use transesterification catalysts, polycondensation catalysts, heat stabilizers, light stabilizers, polymerization modifiers, solvents, etc.

[0096] The transesterification catalyst is not particularly limited, but examples thereof include alkoxides, organic acid salts, inorganic acid salts, and metal oxides containing alkaline earth metals such as magnesium, calcium, and barium; and alkoxides, organic acid salts, inorganic acid salts, and metal oxides containing transition metals such as manganese, zinc, cobalt, and titanium. Among these, manganese acetate and calcium acetate are preferably used.

[0097] The type of polycondensation catalyst is not particularly limited, and examples thereof include compounds containing alkaline earth metals, transition metals, metals of Group 13 of the periodic table, metals of Group 14 of the periodic table, and metals of Group 15 of the periodic table. More specific examples include germanium compounds such as germanium dioxide, germanium hydroxide, germanium oxalate, germanium tetraethoxide, and germanium-n-butoxide; antimony compounds such as antimony trioxide, antimony acetate, and antimony ethylene glycolate; and titanium compounds such as tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, titanium oxalate, and potassium titanium oxalate. These catalysts may be used alone or in combination of two or more.

[0098] The heat stabilizer is not particularly limited, but examples thereof include phosphorus compounds such as trimethyl phosphate, triethyl phosphate, triphenyl phosphate, phosphorous acid, trimethyl phosphite, and triethyl phosphite.

[0099] The polymerization reaction may be carried out in air or in an inert gas atmosphere. The reaction may be carried out under normal pressure or reduced pressure. The reaction temperature may be, for example, 150 to 300°C, 180 to 290°C, or 200 to 280°C.

[0100] 1.2. Thermoplastic acrylic resin layer The thermoplastic acrylic resin layer contains a thermoplastic acrylic resin, and may contain core-shell type rubber particles and the additives described in the polyester resin layer, as necessary.

[0101] The thickness ratio of the thermoplastic acrylic resin layer to the entire optical film is 70 to 99%, preferably 75 to 97.5%, and more preferably 80 to 95%. When the thickness ratio of the thermoplastic acrylic resin layer is within the above range, the retardation in the thickness direction is further reduced, and flexibility and mechanical strength tend to be further improved.

[0102] 1.2.1. Acrylic resin The acrylic resin is a polymer containing structural units derived from a (meth)acrylic acid ester, and may be a homopolymer of a (meth)acrylic acid ester or a copolymer with other polymerizable monomers.

[0103] Such an acrylic resin may contain a repeating unit having no cyclic structure in the main chain, as shown in the following general formula (4), or a repeating unit having a cyclic structure in the main chain, as shown in the following general formula (5) or (6). [ka] [In the formula, R 6a and R 6b are the same or different and are hydrogen atoms or C 1-8represents an alkyl group, and R 7a and R 7b are the same or different and are hydrogen atoms, C 1-18 Alkyl group, C 3-12 Cycloalkyl group, or C 5-15 represents a substituent containing an aromatic ring, s and t represent mole fractions, and s+t=1.] [ka] [In the formula, R 8 represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms, which may contain an oxygen atom; R 9 is a hydrogen atom, C 1-18 Alkyl group, C 3-12 Cycloalkyl group, or C 5-15 R represents a substituent containing an aromatic ring. 10 is a hydrogen atom or C 1-8 represents an alkyl group.] [ka] [In the formula, R 11 and R 12 are the same or different and are hydrogen atoms or C 1-8 represents an alkyl group, and R 13 is a hydrogen atom, C 1-18 Alkyl group, C 3-12 Cycloalkyl group, or C 5-15 indicates a substituent containing an aromatic ring.]

[0104] The monomer represented by general formula (4) is not particularly limited, but examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, benzyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, chloromethyl (meth)acrylate, 2-chloroethyl (meth)acrylate, etc. These monomers may be used alone or in combination of two or more.

[0105] Among these, acrylic resins containing structural units derived from methyl (meth)acrylate are preferred, and polymethyl methacrylate (PMMA) is preferred. Use of such a thermoplastic acrylic resin layer tends to further improve bending resistance and mechanical strength.

[0106] The content of the structural units derived from methyl (meth)acrylate is preferably 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, based on the total amount of the acrylic resin. The upper limit of the content of the structural units derived from methyl (meth)acrylate is not particularly limited, but may be 100% by mass.

[0107] Examples of the cyclic structure of the acrylic resin having a cyclic structure in the main chain include a lactone ring, a glutarimide ring, a glutaric anhydride structure, a maleic anhydride structure, and an N-substituted maleimide structure.

[0108] The acrylic resin having a lactone ring represented by general formula (5) is not particularly limited, but may be produced, for example, by copolymerizing a (meth)acrylic acid ester with a hydroxyl group-containing (meth)acrylic acid ester and / or a carboxylic acid group-containing (meth)acrylic acid as monomers, followed by an intramolecular cyclization reaction of the resulting polymer. Commercially available products of such acrylic resins include, for example, Acriview manufactured by Nippon Shokubai Co., Ltd.

[0109] The monomer having a hydroxyl group is not particularly limited, but examples thereof include methyl 2-(hydroxymethyl)acrylate, ethyl 2-(hydroxymethyl)acrylate, methyl 2-(hydroxyethyl)acrylate, etc. These monomers may be used alone or in combination of two or more.

[0110] The monomer having a carboxylic acid group is not particularly limited, but examples thereof include acrylic acid, methacrylic acid, crotonic acid, 2-(hydroxymethyl)acrylic acid, 2-(hydroxyethyl)acrylic acid, etc. These monomers may be used alone or in combination of two or more.

[0111] The acrylic resin having a glutarimide ring represented by general formula (6) is not particularly limited, but may be produced, for example, by adding a primary amine to a (meth)acrylic acid ester polymer and carrying out imidization.

[0112] The monomer constituting the (meth)acrylic acid ester polymer is not particularly limited, but examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, benzyl (meth)acrylate, and cyclohexyl (meth)acrylate. Among these, methyl (meth)acrylate is preferred. These monomers may be used alone or in combination of two or more.

[0113] The acrylic resin having a maleic anhydride structure or an N-substituted maleimide structure is not particularly limited, but may be produced, for example, by copolymerizing maleic anhydride or an N-substituted maleimide monomer with a (meth)acrylic acid ester.

[0114] Commercially available maleic acid modified resins are not particularly limited, but examples thereof include Delpet 980N manufactured by Asahi Kasei Chemicals Corporation, which is a maleic acid modified MAS resin (methyl methacrylate-acrylonitrile-styrene copolymer).

[0115] The acrylic resin has a weight average molecular weight of 1.0 × 10 4 It is preferable that the acrylic resin used as the modifier contains the above acrylic resin. This tends to further improve flex resistance and mechanical strength. The weight average molecular weight of the acrylic resin used as the modifier is preferably 1.0 × 10 4 or more, 5.0 x 10 4 is equal to or greater than 1.0 x 105 ~1.0×10 6 When the weight average molecular weight is within the above range, the flex resistance and mechanical strength tend to be further improved.

[0116] The content of the acrylic resin as a modifier is preferably 1 to 10 mass %, 1 to 5 mass %, or 1 to 3 mass % relative to the total amount of the thermoplastic acrylic resin layer. When the content of the acrylic resin is within the above range, bending resistance and mechanical strength tend to be further improved.

[0117] The commercially available acrylic resin modifier is not particularly limited, but examples thereof include Metablen P-531A and P-530A manufactured by Mitsubishi Chemical Corporation, which are acrylic polymer processing aids. , P-551A, P-550A, P-501A, P-570A, etc.

[0118] 1.2.2. Rubber particles The thermoplastic acrylic resin layer may contain rubber particles, which further improves the toughness of the thermoplastic acrylic resin layer, prevents cracks during transport or shape change of the optical film, and improves the slipperiness.

[0119] In this embodiment, "during transport" refers to transporting the film in the extrusion step described below, stretching the optical film in the stretching step, or transporting the optical film sandwiched between a tenter or the like.

[0120] In this embodiment, "changing the shape" means bending or rolling the optical film.

[0121] The elastic material constituting the rubber particles is not particularly limited, but examples thereof include olefin-based elastic polymers, diene-based elastic polymers, styrene-diene-based elastic copolymers, acrylic elastic polymers, etc. Among these, acrylic elastic polymers are preferred from the viewpoint of transparency.

[0122] The rubber particles may be particles consisting of only a layer exhibiting rubber elasticity, or may be particles having a multilayer structure having a layer exhibiting rubber elasticity and another layer. For example, the rubber particles may have a two-layer structure having an acrylic elastic polymer layer and a hard polymer layer mainly composed of alkyl methacrylate on the outside, or a three-layer structure having an acrylic elastic polymer layer and a hard polymer layer mainly composed of alkyl methacrylate on the inside.

[0123] The content of the rubber particles is preferably 1 to 60 mass %, 5 to 40 mass %, or 10 to 25 mass % relative to the total amount of the thermoplastic acrylic resin layer. When the content of the rubber particles is within the above range, the bending resistance is further improved and cracks when changing the shape tend to be reduced.

[0124] Commercially available rubber particles are not particularly limited, but examples thereof include Parapet GR-F and GR-FH manufactured by Kuraray Co., Ltd.

[0125] 1.3.Other Layers The optical film of this embodiment may have on its surface one or more layers selected from the group consisting of an easy-adhesion layer, a hard coat layer, an antiglare layer, an antireflection layer, a low-reflection layer, an antifouling layer, and an antifingerprint layer.

[0126] The adhesive layer is a layer for improving the adhesiveness of the optical film surface, and may be intended to improve the adhesiveness to a polarizer, for example. The resin constituting the adhesive layer is not particularly limited, but examples thereof include a urethane resin, an epoxy resin, and an acrylic resin.

[0127] The hard coat layer is a layer for further improving the hardness of the optical film surface and improving resistance to scratches and abrasion. The resin constituting the hard coat layer is not particularly limited, but examples thereof include a thermosetting resin composition or a photocurable resin composition containing a silicone resin, an acrylic resin, or the like.

[0128] The anti-glare layer has an uneven surface and scatters the reflected light from the optical film surface, thereby reducing the glare and reflection of light and improving visibility. The anti-glare layer is not particularly limited, but an example thereof is a resin layer containing fine particles of Yukimata.

[0129] The anti-reflection layer and the low-reflection layer are layers that reduce surface reflection, thereby increasing the amount of transmitted light and improving the clarity and contrast of images. The anti-reflection layer and the low-reflection layer are not particularly limited, and examples thereof include a single layer having a refractive index lower than that of the optical film, and a multilayer in which a layer with a low refractive index is laminated on a layer with a high refractive index.

[0130] The antifouling layer is said to make it difficult for dirt to adhere and to make it easy to remove any dirt that does adhere. Examples of resins that make up the antifouling layer include those that enhance antifouling properties by imparting water repellency and / or oil repellency. Examples of such antifouling layers include, but are not limited to, layers containing antifouling agents such as silicon oxides, fluorine-containing silane compounds, fluoroalkyl silazanes, fluoroalkyl silanes, fluorine-containing silicon compounds, and perfluoropolyether group-containing silane coupling agents.

[0131] The anti-fingerprint layer is a layer that prevents fingerprints and sebum from adhering to the surface. There are no particular limitations on the type of anti-fingerprint layer, but it may be, for example, a layer that improves wettability to make fingerprint components less noticeable even if they are attached, or a layer made of an organic material that exhibits water-repellent and oil-repellent properties, such as a fluorine-based polymer.

[0132] 2. Other Aspects of Optical Films Although the optical film essentially comprising a polyester resin layer containing an arylated fluorene-based polyester resin and a thermoplastic acrylic resin layer containing an acrylic resin has been described above, in another embodiment, a polycarbonate resin layer containing an arylated fluorene-based polycarbonate resin may be used instead of the polyester resin layer containing the arylated fluorene-based polyester resin. In this specification, the "polyester resin layer" also includes the above-mentioned "polycarbonate resin layer."

[0133] A multilayer film having a polycarbonate resin layer and a thermoplastic acrylic resin layer containing an acrylic resin can also achieve the same effects as the optical film having the polyester resin layer. That is, by including an arylated fluorene-based polycarbonate resin, toughness is improved compared to a film made of an acrylic resin alone, and further, it is possible to make the polycarbonate resin exhibit high ultraviolet absorption ability.

[0134] As the arylated fluorene-based polycarbonate resin, various types can be used without any particular limitation as long as they contain a structural unit having an arylated fluorene-based skeleton, and aromatic polycarbonate resins are preferred because they have high moldability and excellent toughness.In particular, bisphenol A-based polycarbonate resins are preferred because they are widely used and can reduce costs.

[0135] 3. Optical film manufacturing method The method for producing the optical film of the present embodiment is not particularly limited as long as it includes an extrusion step of melt-extruding an arylated fluorene-based polyester resin and an acrylic resin to form a multilayer film of a polyester resin layer and a thermoplastic acrylic resin layer.

[0136] The method for producing an optical film may further include, as necessary, a drying step of drying the arylated fluorene-based polycarbonate resin to a moisture content of less than 100 ppm before the extrusion step, or a stretching step of stretching an unstretched multilayer film.

[0137] The melting temperature of each resin is preferably 50 to 180°C higher than the glass transition temperature (Tg), more preferably 80 to 150°C higher than the glass transition temperature. When the melting temperature in the extruder is 50°C or more higher than the glass transition temperature, the fluidity of the resin tends to be further improved. Furthermore, when the melting temperature in the extruder is 180°C or less lower than the glass transition temperature, deterioration of the resin during melting tends to be suppressed.

[0138] The resin is melted by an extruder and continuously sent to a die via a filter and a gear pump as needed. Each molten resin is subjected to high-precision filtration to remove foreign matter contained in the resin. The filter material used for high-precision filtration of the molten resin is not particularly limited, but a stainless steel sintered filter material is preferred because of its excellent removal performance.

[0139] Additives may be added in the extrusion process as needed. The method for adding additives is not particularly limited, but for example, they can be added by supplying them together with the raw resin to a single-screw or twin-screw extruder and melt-kneading them. The additives may be added in an extruder different from the melt-film-forming device before film formation, or in an extruder attached to a T-die during film formation, but the latter, which allows melt-kneading and film formation to be carried out continuously, is industrially advantageous. Kneading using a twin-screw extruder is suitable for sufficient dispersion of the additives.

[0140] The stretching may be performed by heating the multilayer film produced by coextrusion to a temperature between the melting points and the glass transition points of the polyester resin and the acrylic resin. The stretching may be either biaxial or uniaxial, but uniaxial stretching is preferred from the viewpoint of adjusting the thickness retardation Rth(589) and the in-plane retardation Ro(550).

[0141] In the uniaxial stretching or biaxial stretching, the stretching ratio in each direction is preferably 1.1 to 5.0, 1.2 to 4.5, or 1.3 to 4.0. When the stretching ratio is 1.1 or more, the thickness of the obtained optical film tends to be reduced and the retardation tends to be increased. Furthermore, when the stretching ratio is 3.5 or less, breakage of the optical film tends to be further suppressed.

[0142] The stretching temperature is preferably Tg-10°C or higher and Tg+20°C or lower, Tg-5°C or higher and Tg+15°C or lower, or Tg°C or higher and Tg+10°C or lower. Here, Tg represents the higher of the glass transition temperatures of the polyester resin and the acrylic resin. When the stretching temperature is Tg-10°C or higher, the optical film can be stretched uniformly, and breakage of the optical film tends to be further suppressed. Furthermore, when the stretching temperature is Tg+20°C or lower, the retardation tends to be large and the film thickness tends to be uniform.

[0143] The difference ΔTg between the glass transition temperatures of the polyester resin and the acrylic resin should be as small as possible, preferably ΔTg of 10°C or less.

[0144] By preheating before stretching and heat setting after stretching, the variation in retardation value after stretching can be reduced, and the variation in orientation angle due to bowing can be reduced. Either preheating or heat setting can be performed, but both are more preferable. These preheating and heat setting are preferably performed by holding with clips, that is, preferably performed consecutively with stretching.

[0145] The preheating temperature is preferably Tg-5° C. to Tg+40° C., or Tg to Tg+30° C. The preheating time is preferably 1 second to 10 minutes, 5 seconds to 4 minutes, or 10 seconds to 2 minutes.

[0146] The heat setting temperature is preferably Tg-5°C to Tg+25°C, or Tg to Tg+15°C. The heat setting temperature may be preferably 1°C to 50°C lower, 2°C to 40°C lower, or 3°C to 30°C lower than the stretching temperature. The heat setting temperature is more preferably equal to or lower than the stretching temperature and Tg or lower. The heat setting time is preferably 1 second to 10 minutes, 5 seconds to 4 minutes, or 10 seconds to 2 minutes. During heat setting, the width of the tenter is preferably reduced by about 0 to 10% from the width after stretching.

[0147] The melting temperature of each resin to be extruded is preferably Tg+80° C. or higher, Tg+100° C. or higher, Tg+180° C. or lower, or Tg+150° C. When the melting temperature of the resin to be extruded is equal to or higher than the lower limit of the above range, the fluidity of the resin can be sufficiently increased to improve moldability, and when it is equal to or lower than the upper limit, deterioration of the resin can be suppressed.

[0148] The stretching method is not particularly limited, and in the case of biaxial stretching, either a tenter method (also called a flat method) or a tube method may be used, but the tenter method, which is excellent in uniformity of stretched thickness, is preferred. The biaxial stretching may be sequential biaxial stretching or simultaneous biaxial stretching.

[0149] Optical films have superior mechanical properties (e.g., tensile strength, tensile elongation, brittleness, etc.) compared to general acrylic resin films, and therefore can be made thinner. Stretching treatment increases the tensile strength and prevents brittleness, making it less susceptible to cracking, easier to handle, and thinner. The optical film of this embodiment can also be manufactured to a thickness of 25 μm or less.

[0150] 4. Polarizing plate The polarizing plate of this embodiment includes a polarizer protective film, a retardation film, and a polarizer located between the polarizer protective film and the retardation film, and the polarizer protective film is the optical film. Figures 2A and 2B are cross-sectional views schematically illustrating one embodiment of the polarizing plate.

[0151] 2A is formed by laminating a retardation film 21, a polarizer 23, and a polarizer protective film 10 in this order. As shown in the figure, an adhesive layer 22 may be provided between the retardation film 21 and the polarizer 23, or an adhesive layer 24 may be provided between the polarizer 23 and the polarizer protective film 10.

[0152] 2B is obtained by laminating a retardation film 31, a polarizer protective film 10, a polarizer 34, and a polarizer protective film 10 in this order. An adhesive layer 32 may be provided between the retardation film 31 and the polarizer protective film 10, and adhesive layers 33 and 35 may be provided between the polarizer 34 and the polarizer protective film 10.

[0153] The polarizer protective film 10 may be subjected to a corona treatment, a plasma treatment, or a surface modification treatment using an aqueous solution of a strong base such as sodium hydroxide or potassium hydroxide in order to improve adhesion to the polarizers 23 and 34. These surface modification treatments may be performed after the film formation step or after the stretching step.

[0154] The polarizers 23 and 34 are not particularly limited as long as they are conventionally known, and examples thereof include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified ethylene-vinyl acetate copolymer films that have been dyed with iodine or a dichroic substance such as a dichroic dye and stretched; oriented polyene films such as dehydrated polyvinyl alcohol films and dehydrochlorinated polyvinyl chloride films; and polarizers obtained by dyeing polyvinyl alcohol films with iodine and uniaxially stretching them.

[0155] The above-described polarizer protective films can be used as the polarizer protective film 10. The polarizer protective film 10 and the polarizers 23 and 34 formed of a polyvinyl alcohol-based resin or the like may be bonded together with an ultraviolet-curable adhesive (adhesive layers 24, 33, and 35).

[0156] As an adhesive used to bond a polarizer protective film to a polarizer, conventionally, water-based adhesives used in TAC films, such as polyvinyl alcohol and polyvinyl butyral, have low moisture permeability in polyethylene terephthalate resin and acrylic resin films, resulting in slow drying speed of water, and are therefore undesirable from the viewpoint of productivity. Therefore, it is preferable to use an ultraviolet-curable adhesive.

[0157] The properties required for UV-curable adhesives used in the manufacturing process of polarizing plates include not only adhesive strength, but also solvent-freeness, viscosity of the coating liquid, integrated light dose, heat resistance, coating thickness, etc. The viscosity of the coating liquid, integrated light dose, and coating thickness are particularly important because they affect production speed.

[0158] The ultraviolet-curable adhesive is not particularly limited, but examples thereof include a radical polymerizable composition containing a urethane acrylate oligomer, which is a reaction product of an aromatic polyester polyol, a polyfunctional isocyanate, and a hydroxyl group-containing acrylate, and a monofunctional acrylate. A composition containing a urethane acrylate oligomer, which is a reaction product of a polyester polyol having a 9,9-bis(aryl)fluorene skeleton, a diisocyanate compound, and a hydroxyl group-containing acrylate compound, and a monofunctional acrylate compound is preferred. For details of such compositions, the contents disclosed in JP 2018-087284 A can be incorporated by reference.

[0159] The UV-curable adhesive contains a urethane acrylate oligomer, which provides excellent adhesion between the protective film and the PVA polarizer, as well as excellent curing properties. Furthermore, the urethane acrylate oligomer has a 9,9-bis(aryl)fluorene skeleton and an alicyclic carboxylic acid structure in its main chain, which provides even better adhesion, as well as excellent heat resistance, water resistance, and low cure shrinkage. Examples of compounds that form a 9,9-bis(aryl)fluorene skeleton include 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorenes and 9,9-bis[4-(2-hydroxyethoxy)naphthyl]fluorenes. Examples of compounds that form an alicyclic carboxylic acid structure include 1,4-cyclohexanedicarboxylic acid.

[0160] The UV-curable adhesive uses an alicyclic diisocyanate as the polyfunctional isocyanate, which provides excellent heat resistance, water-resistant adhesion, and coating flexibility. Examples of alicyclic diisocyanates that can be used include hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane.

[0161] As the hydroxyl group-containing acrylate for the ultraviolet curing adhesive, for example, 2-hydroxyethyl acrylate or 2-hydroxypropyl acrylate, which has excellent curing properties, can be used.

[0162] UV-curable adhesives use monofunctional acrylates as diluent monomers to adjust their viscosity. Examples of monofunctional acrylates that can be used include benzyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, and phenoxyethyl acrylate, which have excellent coating properties, water resistance, and adhesion with minimal cure shrinkage. The use of these monofunctional acrylates allows for a wide range of viscosity adjustment without compromising adhesive properties. From the standpoint of coating speed, low viscosity monofunctional acrylates are preferred, with a viscosity in the range of 100 to 500 mPa·s at room temperature (25°C).

[0163] The UV-curable adhesive may contain a photoradical polymerization initiator. Examples of photoradical polymerization initiators include Irgacure 184, 907, 651, 1700, 1800, 819, 369, and 261, Darocur-TPO (Ciba Specialty Chemicals), Darocur-1173 (Merck), Esacure KIP150, and TZT (Nippon Siber Hegner), Kayacure BMS, and Kayacure DMBI (Nippon Kayaku). To efficiently cure the UV-curable adhesive, it is preferable to select a photoradical polymerization initiator with an absorption wavelength different from that of the polarizer protective film.

[0164] The cumulative amount of ultraviolet light is not particularly limited, but the wavelength is 200 to 450 nm and the illuminance is 1 to 500 mW / cm. 2 of light, 10 to 5000 mJ / cm 2 It is preferable to irradiate and expose the film so that the cumulative light amount is 10 mJ / cm 2 When the cumulative light dose is 5000 mJ / cm or more, the curing of the ultraviolet-curable composition is further accelerated, and the required performance tends to be exhibited more effectively and reliably. 2 If the cumulative light amount is less than 100 mJ / cm 2 , the irradiation time can be shortened, and productivity can be further improved. 2 , and more preferably 200 to 300 mJ / cm 2 As the light irradiation device, for example, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, an excimer lamp, or the like is preferably used.

[0165] 5. Image display device Next, the image display device of this embodiment will be described with reference to Figures 3A and 3B. The image display device of this embodiment is not particularly limited as long as it is equipped with the polarizing plate, and examples thereof include organic electroluminescence (EL) display devices and liquid crystal display devices. The image display device of this embodiment is preferably configured to be shape-changeable like a flexible device or configured for in-vehicle use.

[0166] Furthermore, the image display device is not limited to a device that is distributed on the market as a standalone final product, but may also be a part of an information processing device described below, such as a smartphone, etc. Fig. 3A is a cross-sectional view that schematically illustrates an organic EL display device according to one aspect of the present embodiment, and Fig. 3B is a cross-sectional view that schematically illustrates a liquid crystal display device according to one aspect of the present embodiment.

[0167] 3A, an organic EL display device 40 includes, in this order, an organic EL display panel 41, a polarizing plate 20 including the polarizer protective film 10 of this embodiment, and a front panel 43. By using the polarizing plate 20 including the polarizer protective film 10, the organic EL display device 40 can suppress deterioration of the polarizing plate 20 due to ultraviolet rays and moisture permeation, has excellent mechanical strength against bending, and is thinner.

[0168] Furthermore, the organic EL display device 40 may include other components such as a touch sensor 42, as necessary. By providing the touch sensor 42, the organic EL display device 40 functions not only as a display device but also as an information input interface. Each layer constituting the organic EL display device 40 may be bonded to each other using an adhesive layer.

[0169] As shown in FIG. 3B, the liquid crystal display device 50 includes, in this order, a light source 51, a polarizing plate 30, a liquid crystal panel 52, another polarizing plate 30, and a front panel 53. The light source 51 may be a direct type in which light sources are evenly arranged directly below the liquid crystal panel, or an edge light type provided with a reflector and a light guide plate. Furthermore, although FIG. 3B shows the front panel 53, the liquid crystal display device 50 does not necessarily have to include the front panel 53. Furthermore, the liquid crystal display device 50 may further include a touch sensor (not shown).

[0170] The screen of the image display device is not limited to a rectangular shape, but may be a circle, an ellipse, or a polygon such as a triangle or a pentagon. Furthermore, the image display device may be flexible, and its shape may be changed by being warped, bent, rolled up, or folded. For example, as shown in FIG. 4, the image display device includes a rollable display that can be used by pulling out an image display device 61 stored in a rolled state in an image display device storage unit 62.

[0171] 6. Information Processing Device Next, an information processing device of this embodiment will be described with reference to Fig. 5. This figure is a perspective view schematically showing an information processing device 60 of this embodiment. The information processing device 60 includes the image display device having the polarizing plate. The image display device 61 can have the configuration of the organic EL display device 40 or the liquid crystal display device 50 described above, for example.

[0172] Such information processing devices 60 include, but are not limited to, devices equipped with an image display device capable of changing its shape, such as a smartphone or a flexible device, as well as various devices capable of processing information, such as personal computers and tablet terminals. The thinness of the polarizing plate of this embodiment is particularly useful in personal computers, smartphones, tablet terminals, and the like, which are desired to be thin and compact. Furthermore, even thinner personal computers, smartphones, tablet terminals, and the like that are portable and used in various places, such as indoors and outdoors, can be made even thinner.

[0173] Further, examples of the information processing device 60 include a foldable smartphone (Figure 6) that has a foldable image display device 61 and can be folded, and a rollable smartphone (Figure 7) that can be used by pulling out the image display device 61 stored in a rolled state.

[0174] Furthermore, the image display device 61 may have a function as an input / output interface for the information processing device, and may have a function as an output interface for outputting various processing results of the information processing device, or an input interface such as a touch panel for operating the information processing device. Other components of the information processing device are not particularly limited, but may typically include a processor, a communication interface for controlling wired or wireless communication, an input / output interface other than the image display device, a memory, a storage, and one or more communication buses for interconnecting these components. [Example]

[0175] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0176] [Evaluation method] (glass transition temperature (Tg)) Using a differential scanning calorimeter (Seiko Instruments Inc., "DSC 6220"), the sample was placed in an aluminum pan and Tg was measured in the range of 30°C to 200°C in accordance with JIS K7121.

[0177] (molecular weight) Using gel permeation chromatography (manufactured by Tosoh Corporation, "HLC-8120GPC"), the sample was dissolved in chloroform and the weight average molecular weight Mw was measured in terms of polystyrene.

[0178] (In-plane retardation Ro(550), thickness retardation Rth(589)) Using a retardation measurement device (Otsuka Electronics Co., Ltd., "RETS-100"), the in-plane retardation Ro(550) of the film at a wavelength of 550 nm and the thickness retardation Rth(589) at a wavelength of 589 nm were measured at a measurement temperature of 20°C.

[0179] (average thickness) Using a thickness gauge ("Micrometer" manufactured by Mitutoyo Corporation), measurements were taken at three equally spaced points between the chucks in the longitudinal direction of the film, and the average value was calculated.

[0180] (Pencil hardness) The pencil hardness of the surface of the optical film on which the layer to be tested was disposed was measured using a pencil hardness tester (with a level) in accordance with JIS K5600. The measurement conditions were a pencil angle of 45° from the horizontal, a load of 500 g, a test speed of 1 mm / sec, and a test length of 20 mm. The maximum pencil hardness that did not visually scratch the optical film was taken as the pencil hardness. The pencil hardness tester used was a HEIDON-14D manufactured by Shinto Scientific.

[0181] (Bending resistance) Films cut into 15 mm × 30 mm pieces were subjected to a bending test using a bending tester (Yuasa System Co., Ltd., "DMLHP-CS") at a room temperature of 23°C, with a bending radius of 2 mm, a bending speed of 30 times / min, and a bending angle of 180°. The film was bent up to 100,000 times, and the number of times it was bent until it broke was counted to evaluate its bending resistance as follows. 〇: Over 100,000 times △: 10,000 times or more but less than 100,000 times ×: Less than 10,000 times

[0182] (spectral transmittance) The spectral transmittance at 380 nm was measured using "U-3010" (manufactured by HITACHI).

[0183] (Visibility of polarized sunglasses) A model of an image display device that emits linearly polarized light was created by laminating a linear polarizer on the surface of a thin LED tracing stand "SLT-A4C" (Mutoh Industries Ltd.). The produced optical film was superimposed on the linear polarizer so that the angle between the slow axis of the optical film and the absorption axis of the linear polarizer was 45°, and then the visibility of the polarized sunglasses was evaluated by having a person wearing polarized sunglasses visually observe the film. ○: No sudden color change or blackout phenomenon occurs when visually observed from any direction. ×: A sudden change in color or blackout occurs at any observation accuracy.

[0184] [Raw materials] (diol) BPEF: 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, manufactured by Osaka Gas Chemicals Co., Ltd. EG: Ethylene glycol

[0185] (dicarboxylic acid) FDP-m: 9,9-bis(2-carboxyethyl)fluorene, Synthesis Example 1 DNFDP-m: 9,9-bis(2-methoxycarbonylethyl)2,7-di(2-naphthyl)fluorene, Synthesis Example 2

[0186] (acrylic resin) PMMA: Polymethyl acrylate, Parapet SP-01, manufactured by Kuraray Co., Ltd. (rubber particles) Acrylic rubber particles: Parapet GR-F, manufactured by Kuraray (Hard Coating Materials) Hard coating agent: LCH2391-92, manufactured by Toyochem Co., Ltd. Polymerization initiator: Omnirad819, manufactured by BASF

[0187] (Synthesis Example 1: FDP-m: Dimethyl ester of 9,9-bis(2-carboxyethyl)fluorene) 200 mL of 1,4-dioxane and 33.2 g (0.2 mol) of fluorene were placed in a reactor and stirred to dissolve the fluorene. After cooling to 10°C, 3.0 mL of a 40% by weight methanol solution of trimethylbenzylammonium hydroxide (Tokyo Chemical Industry Co., Ltd., "Triton B40") was added dropwise and stirred for 30 minutes. Next, 37.9 g (0.44 mol) of methyl acrylate was added and stirred for approximately 3 hours. After the reaction was completed, 200 mL of toluene and 50 mL of 0.5 N hydrochloric acid were added for washing. After removing the aqueous layer, the organic layer was washed three times with 30 mL of distilled water. The solvent was evaporated to obtain 84.0 g (99% yield) of 9,9-bis(t-butylpropionate)fluorene [9,9-bis{2-(t-butoxycarbonyl)ethyl}fluorene]. Furthermore, the product was dissolved in 300 mL of isopropyl alcohol at 70° C., and then cooled to 10° C. for recrystallization, yielding 9,9-bis(2-methoxycarbonylethyl)fluorene.

[0188] (Synthesis Example 2: DNFDP-m: 9,9-bis(2-methoxycarbonylethyl)2,7-di(2-naphthyl)fluorene) 9,9-bis(2-methoxycarbonylethyl)-2,7-dibromofluorene (DBrFDP-m) was synthesized in the same manner as in Example 1 of JP 2005-89422 A, except that methyl acrylate [37.9 g (0.44 mol)] was used instead of t-butyl acrylate and 2,7-dibromo-9H-fluorene [54.7 g (0.17 mol)] was used instead of fluorene.

[0189] A reactor was charged with 192.3 g (0.39 mol) of DBrFDP-m, 200 g (1.2 mol) of 2-naphthylboronic acid, 4.3 L of dimethoxyethane, and 1 L of 2 M aqueous sodium carbonate. Under a nitrogen stream, 22.4 g (19.4 mmol) of tetrakis(triphenylphosphine)palladium(0) [or Pd(PPh3)4] was added and the mixture was heated to reflux at an internal temperature of 71–78°C for 5 hours. After cooling to room temperature, 2.0 L of toluene and 500 mL of ion-exchanged water were added, followed by five separate extractions and washings. The organic layer changed color from deep orange to brown. The insoluble matter was filtered and concentrated to yield 305 g of brown crude crystals. The resulting crude crystals were dissolved in a mixture of 1.5 kg of ethyl acetate and 300 g of isopropyl alcohol (IPA) by heating, cooled to below 10°C with ice water, and stirred for 1 hour to precipitate crystals. The precipitated crystals were filtered and dried under reduced pressure to obtain 130 g of gray-brown crystals. The obtained gray-brown crystals were purified by column chromatography (silica gel carrier, developing solvent chloroform:ethyl acetate (volume ratio) = 4:1), then recrystallized from methanol and dried under reduced pressure to obtain 116 g of 9,9-bis(2-methoxycarbonylethyl)-2,7-di(2-naphthyl)fluorene (DNFDP-m) represented by the following formula (white crystals, yield 54.9%, HPLC purity 99.4% area%).

[0190] [Preparation of raw materials] (Polymerization of fluorene-based polyester) [Manufacturing Example 1] 0.75 mol of DNFDP-m, 0.2 mol of BPEF, 0.25 mol of FDP-m, 2.8 mol of EG, and 2 × 10 mol of manganese acetate tetrahydrate as a transesterification catalyst were added. -4 8×10 mol of calcium acetate monohydrate -4 The mixture was heated to 230°C and gradually melted with stirring. -4 moles of germanium oxide 20 x 10 -4 EG was removed while gradually increasing the temperature and reducing the pressure until the temperature reached 270°C and the pressure reached 0.13 kPa or less. After the predetermined stirring torque was reached, the contents were removed from the reactor and polyester resin pellets were prepared.

[0191] Analysis of the resulting pellets by 1H-NMR revealed that 65 mol% of the dicarboxylic acid components introduced into the polyester resin were derived from DNFDP-m and 35 mol% from FDP-m, and 70 mol% of the diol components introduced were derived from BPEF and 30 mol% from EG. The glass transition temperature (Tg) of the resulting polyester resin was 127°C, and the weight-average molecular weight (Mw) was 90,000. This resin is referred to as Resin I.

[0192] [Manufacturing Example 2] 1.00 mol of FDPM, 0.80 mol of BPEF, 2.20 mol of EG, and 2 x 10 mol of manganese acetate tetrahydrate as a transesterification catalyst were added. -4 8×10 mol of calcium acetate monohydrate -4 The mixture was heated to 230°C and gradually melted with stirring. -4 moles of germanium oxide 20 x 10 -4 EG was removed while gradually increasing the temperature and reducing the pressure until the temperature reached 270°C and the pressure reached 0.13 kPa or less. After the predetermined stirring torque was reached, the contents were removed from the reactor to prepare pellets of fluorene-based polyester (Resin II).

[0193] Analysis of the resulting pellets by 1H-NMR revealed that 100 mol % of the dicarboxylic acid component introduced into the fluorene-based polyester was derived from FDPM, 80 mol % of the diol component introduced was derived from BPEF, and 20 mol % was derived from EG. The resulting fluorene-based polyester had a glass transition temperature (Tg) of 126°C and a weight-average molecular weight (Mw) of 43,600.

[0194] [Manufacturing Example 3] A raw material obtained by dry-blending 90 parts by mass of dried Resin II pellets with 10 parts by mass of an ultraviolet absorber (manufactured by ADEKA Corporation, product name Adekastab LA-F70) was supplied to a twin-screw extruder (manufactured by Technovel Corporation, model number "KZW 15 / 45", screw diameter D = 15 mm, L / D = 32) and kneaded at a screw temperature of 280°C and a rotation speed of 200 rpm to prepare pellets (Resin III).

[0195] [Example 1] (Film forming process) Resin I, which had been dried with hot air overnight at 80°C, and PMMA were used as raw materials and co-extruded using a T-die extruder with three extruders to prepare a two-kind, three-layer, unstretched multilayer film with the layer structure shown in Table 1. The cylinder temperatures were set at 280-300°C for Resin I and 250°C for PMMA. The thickness ratio of each layer was controlled by adjusting the screw rotation speed of each extruder.

[0196] (Stretching process) The optical films of Examples 1 to 4 were produced by uniaxially stretching each of the unstretched multilayer films obtained in the above film-forming process with fixed ends using a tenter stretching device under the stretching conditions shown in Table 1. Various physical properties of the obtained optical films were measured, and the results are shown in Table 2.

[0197] [Example 2] An optical film of Example 2 was produced in the same manner as in Example 1, except that the stretching temperature was changed as shown in Table 1.

[0198] [Example 3] (Hard coat coating process) A hard coat solution was prepared by dissolving 3% by weight of a polymerization initiator (Omnirad819) in Toyochem's (LCH2391-92). The hard coat solution prepared as above was applied to the optical film prepared in Example 1 with an applicator, dried in a dryer at 80°C for 5 minutes, and then irradiated with UV light in a nitrogen atmosphere to prepare the optical film of Example 3.

[0199] [Examples 4 to 5] Optical films of Examples 4 and 5 were produced in the same manner as in Example 1, except that the layer structures were changed as shown in Table 1.

[0200] [Example 6] (Film forming process) The optical film of Example 6 was produced in the same manner as in Example 4, except that the raw materials were Resin I, which had been dried with hot air overnight at 80°C, and a resin mixture obtained by dry-blending 80% by weight of acrylic resin and 20% by weight of acrylic rubber particles.

[0201] [Comparative Examples 1 to 2] Optical films of Comparative Examples 1 and 2 were prepared by forming a multilayer film in the same manner as in Example 1 except that Resin II or III was used, and stretching was carried out in the same manner as in the above Example.

[0202] Comparative Example 3 Various physical properties of the acrylic resin film "PARAPURE HI-50" (thickness 72 μm) manufactured by Kuraray Co., Ltd. were measured.

[0203] [Table 1] *The numbers in parentheses indicate thickness (μm).

[0204] The evaluation results of various optical films are shown in Table 2 below. [Table 2] [Industrial Applicability]

[0205] The present invention has industrial applicability as an optical film. [Explanation of symbols]

[0206] 10...Polarizer protective film, 11...Polyester resin layer, 12...Thermoplastic acrylic resin layer, 20...Polarizing plate, 21...Retardation film, 22...Adhesive layer, 23...Polarizer, 24...Adhesive layer, 30...Polarizing plate, 31...Retardation film, 32, 33...Adhesive layers, 34...Polarizer, 35...Adhesive layer, 40...Organic EL display device, 41...Organic EL display panel, 42...Touch sensor, 43...Front plate, 50...Liquid crystal display device, 51...Light source, 52...Liquid crystal panel, 53...Front plate, 60...Information processing device, 61...Image display device, 62...Image display device housing

Claims

1. a polyester-based resin layer containing an arylated fluorene-based polyester resin; a thermoplastic acrylic resin layer containing an acrylic resin, An optical film formed by stretching, the thickness ratio of the polyester-based resin layer to the entire optical film is 1.0 to 30%; The thickness retardation Rth(589) at a wavelength of 589 nm is −200 to 0 nm, The in-plane retardation Ro(550) at a wavelength of 550 nm is 50 to 160 nm. Optical film.

2. The spectral transmittance at 380 nm is 10% or less. The optical film according to claim 1 .

3. The thickness is 10 to 90 μm. The optical film according to claim 1 .

4. The total light transmittance is 80% or more. The optical film according to claim 1 .

5. The arylated fluorene-based polyester resin contains a structural unit derived from a dicarboxylic acid having an arylated fluorene skeleton. The optical film according to claim 1 .

6. The thermoplastic acrylic resin layer contains rubber particles. The optical film according to claim 1 .

7. The thermoplastic acrylic resin layer is coated with a modifier having a weight average molecular weight of 1.0×10 ５ Contains 0 to 5% of the above acrylic resins, The optical film according to claim 1 .

8. a three-layer structure in which the polyester-based resin layer is positioned as an intermediate layer and the thermoplastic acrylic resin layer is positioned as an outermost layer, or a three-layer structure in which two polyester-based resin layers are laminated together with the acrylic resin layer interposed therebetween, so that the polyester-based resin layer is positioned as an outermost layer and the thermoplastic acrylic resin layer is positioned as an intermediate layer; The optical film according to claim 1 .

9. The content of the ultraviolet absorber in the polyester resin layer is 1% by mass or less. The optical film according to claim 1 .

10. The surface has one or more layers selected from an easy-adhesion layer, a hard coat layer, an anti-glare layer, an anti-reflection layer, a low-reflection layer, an anti-fouling layer, and an anti-fingerprint layer. The optical film according to claim 1 .

11. Used as a polarizer protective film, The optical film according to claim 1 .

12. a polarizer protective film; A retardation film; a polarizer positioned between the polarizer protective film and the retardation film, The polarizer protective film is the optical film according to claim 11. Polarizing plate.

13. A polarizing plate according to claim 12, Image display device.

14. It is possible to change the shape, The image display device according to claim 13.

15. It is for automotive use, The image display device according to claim 13.

16. The image display device according to claim 13, Information processing device.

Images