TWI443365B - Method for producing optical film, optical film, polarizer and display - Google Patents

Description

Optical film manufacturing method, optical film, polarizing plate and display

The present invention relates to an optical film disposed at the front of a display (image display device) such as a liquid crystal display (LCD), a cathode tube display device (CRT), or a plasma display (PDP), a method of manufacturing the same, and a use thereof Polarizer and display.

In the display as described above, in order to improve the visibility of the display surface, it is required to reduce reflection from light irradiated from an external light source such as a fluorescent lamp or sunlight. A method of using an antireflection film provided with a low refractive index layer on the outermost surface of a functional layer such as a hard coat layer is known as a method of suppressing reflection of external light (for example, Patent Document 1).

However, in the invention of Patent Document 1, the composition for forming a functional layer is applied, and the functional layer is formed by semi-hardening by means of free radiation, and the low refractive index layer is formed on the functional layer of the semi-hardened state. In the method of using the composition, the method of completely hardening (half-curing), and the conventional application of coating the composition on each layer of each layer, and then completely hardening the double-layer coating method, because A plurality of coating steps and hardening steps will be performed, and thus productivity is poor.

In view of this situation, Patent Document 2 proposes that the main purpose is to provide two-layer coating of two or more functional layers at the same time, which can achieve high productivity, high interlayer adhesion, and no obstacle to separation of functions between layers. In the method for producing an optical film, the layer A and the layer B each containing an exothermic radiation curable resin are simultaneously subjected to two-layer coating, and after performing the first epilation radiation (prebaking), followed by drying. A method of producing a cured (completely hardened) optical film by performing a second epilation radiation.

However, in addition to the high adhesion between the layers of the two-layer coating, high adhesion between the two-layer coating layer and the substrate or substrate-contacting layer is required. Patent Document 2 has high adhesion between layers and separation of functions between layers, but there is a layer interface between the A layer (hard coat layer or antiglare layer) and the B layer (refractive index control layer) which are simultaneously applied. .

Further, in Patent Document 1, an attempt is made to reduce the refractive index of the low refractive index layer to include low refractive index fine particles such as hollow particles, but if low refractive index fine particles are contained in the low refractive index layer, the low refractive index layer is formed. The refractive index is lowered, but since the refractive index of the functional layer adjacent to the substrate side of the low refractive index layer is higher than that of the low refractive index layer, the boundary (interface) between the low refractive index layer and the functional layer is low. The low refractive index fine particles of the refractive index layer and the functional layer have a refractive index difference. When precise film thickness control is performed, interference fringes occur, resulting in a display surface of the display using the antireflection film, which causes a problem of poor visibility.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2009-053691

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2008-250267

The present invention has been made to solve the above problems, and a first object of the present invention is to provide an anti-reflection function by performing simultaneous coating (double-layer coating), and maintain fog value, total light transmittance, and no plaque. The surface is improved in productivity by reducing the coating step and the hardening step, and by eliminating the interfacial interface caused by successive coatings, the occurrence of interference fringes between the layers is suppressed, and the adhesion is improved. In the vicinity of the substrate, an optical film having a ratio of a hard coating composition having a refractive index of the same refractive index as that of the substrate is added, and interference between the hard coat layer and the substrate is suppressed, and an optical film having excellent adhesion is obtained, and a method for producing the same.

A second object of the present invention is to provide a polarizing plate comprising the above optical film.

A third object of the present invention is to provide a display comprising the above optical film.

The inventors of the present invention have intensively studied and found that the first composition (which does not contain low refractive index fine particles and low refractive index resin, or even contains a low refractive index resin, is also resistant to photocurable resin or thermosetting property). The curable resin of the resin is reduced in mass to 5% by mass or less, and has a specific viscosity, and the second composition (which contains low refractive index fine particles and has a specific viscosity), and the first composition is made from the substrate side. The second composition is adjacent to and simultaneously coated on the substrate or on the layer provided on the substrate, and dried in the case of prebaking without drying, followed by light irradiation or heating. When the curing is performed, the film thickness direction of the HC layer can be obtained in accordance with high productivity, and the presence of the low refractive index fine particles is more on the interface side of the opposite side of the substrate than the substrate side of the HC layer. The distribution of the amount of the low-refractive-index microparticles decreases as the substrate side is formed, that is, the distribution of the low-refractive-index microparticles gradually decreases toward the substrate side from the interface side of the opposite side of the substrate, and is not formed as conventionally used. Sub-double coating to form a low refractive index When the layer and the HC layer are used, or a clear layer interface which is formed when the coating is formed by simultaneous coating as in Patent Document 2, and has an anti-reflection function, and in the case of maintaining the haze value, the total light transmittance, and the smear-free surface, By eliminating the interlayer interface generated by successive coatings, the occurrence of interference fringes between the layers is suppressed, and the adhesion is improved, and the hard coat composition having the same refractive index as the refractive index of the substrate is added in the vicinity of the substrate. The optical film which suppresses the occurrence of interference fringes between a hard-coat layer and a base material, and is excellent in adhesiveness, has completed the present invention.

That is, the method for producing an optical film of the present invention includes: (i) a step of preparing a light-transmitting substrate; (ii) preparing a curable resin composition for a first hard coat layer and a second hard coat layer. a step of forming a curable resin composition containing a reactive first resin and a first solvent, and containing no low refractive index fine particles and a low refractive index resin, or even containing The low refractive index resin is also 5.0 mass% or less with respect to the mass of the first resin, and the viscosity μ1 is 3 mPa·s or more; the curable resin composition for the second hard coat layer contains a low average particle diameter of 10 to 300 nm. One or more kinds of low refractive index components and a second resin and a second solvent having reactivity are selected from the group consisting of the refractive index fine particles and the low refractive index resin, and the viscosity μ2 is 5 mPa·s or more, and the μ2 buckle is subtracted. The value of μ1 is 30 mPa·s or less; (iii) at least one side of the light-transmitting substrate, and the curable resin composition for the first hard coat layer is The second hard coat layer is adjacent to the hardened resin composition and simultaneously coated And forming a coating film; and (iv) drying the coating film obtained in the above step (iii), followed by performing light irradiation and/or heating to harden; and in the (iii) step and the (iv) Pre-bake is not performed between the steps.

The first HC layer is made of a curable resin which does not contain low-refractive-index fine particles and a low-refractive-index resin, or which contains a low-refractive-index resin, is reduced to 5.0 mass% or less with respect to the first resin, and has the above specific viscosity. (hereinafter referred to as "first composition"), and a second HC layer containing one or more kinds of low refractive index components selected from the group consisting of low refractive index fine particles and low refractive index resins and having the above specific viscosity The curable resin composition (hereinafter referred to as "second composition") is formed by applying a double layer coating to the light-transmitting substrate side while the first composition and the second composition are adjacent to each other. The HC layer is not pre-baked, whereby the low refractive index component contained in the second composition is present in the film thickness direction of the HC layer, and the HC layer is on the opposite side of the light transmissive substrate. The interface side is more on the side of the light-transmitting substrate, and the side of the light-transmissive substrate side is formed such that the amount of the low-refractive-index component decreases, which is from the opposite side of the light-transmitting substrate. The interface is from the side of the light transmissive substrate, and the low refractive index component is By gradually decreasing, it is possible to obtain an interference pattern in which an interference pattern between the low refractive index component and the resin of the HC layer in the HC layer is suppressed, and interference fringes at the interface between the HC layer and the substrate are generated, and the optical property is excellent in visibility. film.

Further, since the coating film is dried without performing prebaking, and then the coating film is cured by light irradiation or heating, the HC layer and the HC layer are improved as compared with the case where the baking is performed by the prebaking. The light-transmitting substrate and the HC layer are adhered to each other by the adjacent layer on the side of the light-transmitting substrate. In the present invention, "prebaking" means light irradiation and/or heating in which the coating film is not substantially hardened. In addition, "the coating film is completely cured" means that the coating film is dried to reduce the solvent in the coating film, and the cured coating film is expressed by a pencil hardness test (4.9 N load) prescribed in JIS K5600-5-4 (1999). Hardening of hardness above "H".

In a preferred embodiment of the method for producing an optical film of the present invention, an optical film may be obtained which has a film thickness of the coating film of the curable resin composition for the first hard coat layer in the step (iii). When T1 is used and the coating film wetting thickness of the curable resin composition for the second hard coat layer is T2, the value of T2 divided by T1 (that is, T2/T1) is set to 0.01 to 1, In the film thickness direction of the hard coat layer, the low refractive index component is present on the opposite side of the opposite side of the light-transmitting substrate of the HC layer, and is more light-receiving. On the side of the penetrating substrate, the distribution of the amount of the low refractive index component decreases, and the low refractive index component gradually decreases from the interface on the opposite side of the light transmissive substrate toward the side of the light transmissive substrate. And in the film thickness direction of the hard coat layer, in the region from the interface on the opposite side of the light-transmitting substrate to the dry film thickness of 70% of the hard coat layer, the low refractive index is present. The distribution of the total composition of 70~100%.

By forming the distribution of such a low refractive index component, even if the content of the low refractive index component is reduced, the antireflection performance of the optical film can be sufficiently exhibited.

Further, the distribution of the low refractive index fine particles in the film thickness direction of the HC layer can be observed by a TEM (transmission electron microscope) photograph of the cross section of the thickness direction of the HC layer.

The low refractive index resin distribution in the film thickness direction of the HC layer is, for example, an optical film is occluded with a thermosetting resin, and an ultrathin slicer manufactured by LEICA Co., Ltd. is used to prepare an ultrathin film having a thickness of 80 nm from the occluded optical film. Sectioning was followed by gas phase staining using RuO4 and observation by TEM.

In a preferred embodiment of the method for producing an optical film of the present invention, it is preferred that the first resin composition for a first hard coat layer has a viscosity μ1 of from 3 to 95 mPa·s, and the second hard coat layer is composed of a curable resin. The viscosity μ2 of the object is 5 to 100 mPa‧s because the HC layer having the specific low refractive index component distribution described above can be easily obtained.

The optical film of the present invention is an optical film obtained in accordance with the above-described method for producing an optical film.

A preferred embodiment of the optical film of the present invention may be an optical film having a hard coat layer on one side of the light-transmitting substrate, wherein the low-refractive-index particles are in the film thickness direction of the hard coat layer. There is a state in which the interface side on the opposite side of the light-transmitting substrate is more on the side of the light-transmitting substrate, and the side of the light-permeable substrate is on the side of the light-permeable substrate. The amount of the lower refractive index component is gradually reduced from the interface on the opposite side from the light-transmitting substrate toward the light-permeable substrate side, and there is no layer interface in the hard coat layer. In the checkerboard adhesion test of the hard coat layer to the light-transmitting substrate, the adhesion ratio can be made 90 to 100%.

Here, the "adhesive ratio of the checkerboard adhesion test" means that the optical film is divided into a checkerboard of 100 squares by 1 mm square on the side surface of the HC layer, and a width of 24 mm adhesive tape is used (for example, the ICICHIBAN system) Five consecutive peeling tests were carried out using cellophane tape (registered trademark), and the ratio of the squares remaining without peeling was calculated according to the following criteria.

Bonding rate (%) = (number of squares without peeling off / total number of squares 100) × 100

In a preferred embodiment of the optical film of the present invention, the film thickness direction of the hard coat layer may be 70% from the interface of the opposite side of the light-transmitting substrate to the dry film thickness of the hard coat layer. In the region up to the above, 70 to 100% of the total amount of the low refractive index fine particles are present.

The polarizing plate of the present invention is provided with a polarizer on the side of the light-transmitting substrate on which the optical film is opposed to the hard coat layer.

In the display of the present invention, the display panel is disposed on the side of the light-transmissive substrate on which the optical film is opposed to the hard coat layer.

a first composition (which does not contain low refractive index fine particles and a low refractive index resin, or a specific refractive index even if a low refractive index resin is contained, and has the specific viscosity described above), and a second composition (which contains a low-refractive-index microparticle and/or a low-refractive-index resin having a specific viscosity as described above, and simultaneously applying the first composition and the second composition in a state of being adjacent to each other from the side of the light-transmitting substrate; The coating film is dried without performing prebaking, and then light irradiation or heating is performed to form an HC layer, whereby low refractive index fine particles and/or low refractive index resin contained in the second composition can be obtained. In the film thickness direction of the HC layer, the interface side of the opposite side of the light-transmitting substrate of the HC layer is more on the side of the light-transmitting substrate, and the side closer to the light-transmitting substrate is a distribution in which the amount of decrease is reduced, and a distribution in which the low refractive index component gradually decreases from the interface on the opposite side of the light-transmitting substrate toward the light-transmitting substrate side, and has an anti-reflection function And maintain the fog value, total light penetration and no plaque Next, the productivity is improved by reducing the coating step and the hardening step, and by eliminating the interlayer interface generated by the successive coating, the occurrence of interference fringes between the layers is suppressed, and the adhesion is improved by the substrate. In the vicinity, an optical film having a ratio of a hard coating composition having a refractive index of the same refractive index as that of the substrate is added, and interference fringes between the hard coat layer and the substrate are suppressed, and the adhesion is excellent.

Hereinafter, first, a method of producing an optical film of the present invention will be described, and then the optical film will be described.

In the present invention, (meth) acrylate means acrylate and/or methacrylate.

Furthermore, the optical system of the present invention is not limited to electromagnetic waves of wavelengths of visible and non-visible regions, and encompasses particle rays such as electron rays, and radiation or free radiation which are collectively referred to as electromagnetic waves and particle rays.

In the present invention, the term "film thickness" means the film thickness (dry film thickness) at the time of drying, unless otherwise stated.

In the present invention, the term "hard coat layer" means a hardness of "H" or more in accordance with a pencil hardness test (4.9 N load) prescribed in JIS K5600-5-4 (1999).

Further, in the definition of the film and the sheet in the definition of JIS-K6900, the term "sheet" means a flat product which is thin and generally has a thickness which is small with respect to the length and the width, and the "film" means the length and the width. The thickness is extremely small, and the maximum thickness is an arbitrarily defined thin flat product, which is generally supplied in the form of a roll. Therefore, the thickness of the sheet is particularly thin, which may also be referred to as a film, because the boundary between the sheet and the film is not necessarily determined, and it is not easy to distinguish clearly. Therefore, the meaning of both the thicker and the thinner is defined as "film".

In the present invention, the term "resin" encompasses the concept of a polymer in addition to a monomer or an oligomer, and becomes a component of a matrix of an HC layer or other functional layer after being cured.

In the present invention, the "molecular weight" means a weight average molecular weight measured by a gel permeation chromatography (GPC) in a THF solvent when a molecular weight distribution is used, when there is no molecular weight distribution. The case refers to the molecular weight of the compound itself.

In the present invention, the "average particle diameter of the low refractive index microparticles" means that the particles in the solution are measured by a dynamic light scattering method in the case of the microparticles of the composition, and the primary particle diameter and the secondary particle diameter are expressed by the cumulative distribution. The 50% particle diameter (d50 intermediate particle diameter) at the time of particle size distribution can be measured using a Microtrac particle size analyzer manufactured by Nikkiso Co., Ltd. When the particles in the HC layer are in the case of the HC layer, the average of 20 particles observed by the TEM photograph is used.

(Method of manufacturing optical film)

A method for producing an optical film of the present invention, comprising: (i) a step of preparing a light-transmitting substrate; (ii) preparing a curable resin composition for a first hard coat layer and a second hard coat layer a step of forming a curable resin composition containing a reactive first resin and a first solvent, and containing no low refractive index fine particles and a low refractive index resin, or even containing The low refractive index resin is also 5.0 mass% or less with respect to the mass of the first resin, and the viscosity μ1 is 3 mPa·s or more; the curable resin composition for the second hard coat layer contains a low average particle diameter of 10 to 300 nm. One or more kinds of low refractive index components and a second resin and a second solvent having reactivity are selected from the group consisting of the refractive index fine particles and the low refractive index resin, and the viscosity μ2 is 5 mPa·s or more, and the μ2 buckle is subtracted. The value of μ1 is 30 mPa·s or less; (iii) at least one side of the light-transmitting substrate, and the curable resin composition for the first hard coat layer is The second hard coat layer is adjacent to the hardening resin composition and is subjected to the same a step of coating to form a coating film; and (iv) a step of drying the coating film obtained in the above step (iii), followed by performing light irradiation and/or heating to cure; and in the step (iii) (iv) Pre-baking is not performed between steps.

Fig. 1 is a schematic cross-sectional view showing an example of distribution of low refractive index fine particles in the HC layer of the optical film obtained by the production method of the present invention.

In the optical film 1, the HC layer 20 is provided on one surface side of the light-transmitting substrate 10, and in the HC layer, the low-refractive-index particles 30 are present on the opposite side of the opposite side of the HC layer from the light-transmitting substrate. More than the light-transmitting substrate side state, and the lighter penetrating substrate side has a smaller amount of distribution, that is, having an interface from the opposite side of the light-transmitting substrate toward The light-transmissive substrate side has a distribution in which the low refractive index component gradually decreases.

Fig. 2 is a schematic cross-sectional view showing an example of distribution of low refractive index fine particles in a low refractive index layer of an antireflection film formed by a sequential double coating method.

The anti-reflection film 100 is provided on one surface side of the light-transmitting substrate 10, and the HC layer 110 and the low-refractive-index layer 120 are provided from the side of the light-transmitting substrate, and the low-refractive-index particles 30 in the low-refractive-index layer are uniform. Since the low refractive index layer is formed after the HC layer is completely hardened, the low refractive index fine particles are not in the HC layer, and the refractive index difference becomes large at the interface between the low refractive index layer and the HC layer. This causes interference patterns. Moreover, the interface between the HC layer and the low refractive index layer can be clearly distinguished. Further, if the thickness of the region where the low-refractive-index microparticles are present in Fig. 1 is thicker than the thickness of the film having the same thickness, the low-refractive-index layer is formed of a conventional anti-reflection film, and interference fringes occur.

According to this, in the conventional double-layer coating method, if the thickness of the low-refractive-index particle distribution obtained by the coating method according to the present invention is formed to the same thickness as the upper layer (low-refractive-index layer), the lower layer is formed. The hardened portion of the composition and the hardened portion of the composition to be the upper layer are formed by an interface, and the refractive index difference between the low refractive index fine particles contained in the upper layer composition and the resin contained in the lower layer composition is Larger, resulting in interference patterns.

On the other hand, in the method for producing an optical film of the present invention, the first composition (which does not contain low refractive index fine particles and low refractive index resin, or even contains a low refractive index resin is also 5.0 with respect to the first resin mass) 5% by mass or less, and having a specific viscosity as described above, and a second composition (which contains a low refractive index component and having the specific viscosity described above), and the first composition and the second composition are supported from the side of the light-transmitting substrate The material is simultaneously coated in an adjacent position to form an HC layer, and by performing prebaking, as shown in FIG. 1, the low refractive index component contained in the second composition is in the film of the HC layer. In the thick direction, the interface side of the opposite side of the light-transmitting substrate of the HC layer is more on the side of the light-permeable substrate, and the side of the light-transmissive substrate is low-refractive-index particles. The distribution in which the amount is decreased, that is, the distribution from the interface side on the opposite side of the light-transmitting substrate toward the light-transmitting substrate side, the distribution of the low refractive index component is gradually decreased, and the low refractive index in the HC layer is suppressed. The interference pattern caused by the difference in refractive index between the composition of the component and the resin of the HC layer, Further, it is possible to suppress interference fringes at the interface between the HC layer and the substrate, and it is excellent in visibility, and excellent in adhesion between the HC layer and the layer adjacent to the light-transmitting substrate or the light-transmitting substrate. film.

Further, since it is not necessary to perform prebaking, it is excellent in productivity in the case where hardening is performed by two-degree light irradiation such as prebaking or main hardening.

Further, when the HC layer containing the low refractive index fine particles having a low refractive index component is simultaneously coated on the light-transmitting substrate, the reason for the good adhesion between the HC layer and the light-transmitting substrate is Not yet clear, but the following reasons can be speculated. That is, if the resin contained in the first composition contacts the light-transmitting substrate, the resin penetrates into the light-transmitting substrate and chemically and/or physically combines, so that it is presumed to be improved. Adhesion between the HC layer and the light-transmitting substrate. On the other hand, when the low-refractive-index microparticles contained in the HC layer are not formed as described above, the amount of the low-refractive-index microparticles is reduced as it is closer to the light-transmitting substrate side, and when it is uniformly dispersed in the HC layer, in HC At the interface of the light-transmissive substrate side of the layer, only the portion occupied by the low-refractive-index microparticles may be infiltrated by the resin without chemical and/or physical bonding between the resin and the substrate, and the adhesion is presumed. Not improved.

Further, if the first composition and the second composition are applied simultaneously on the light-transmitting substrate, pre-baking is performed, and the light penetrating base is infiltrated into the resin in the presence of a solvent. Polymerization or cross-linking will begin before the material starts, resulting in a larger molecular weight of the resin, and the resin will not penetrate into the light-transmitting substrate. Even after drying, light irradiation or heating is performed, and the adhesion is not improved. .

From these phenomena, it is presumed that the first composition and the second composition are simultaneously coated on the light-transmissive substrate, and when the HC layer of the present invention having the specific low-refractive-index particle distribution is formed, it becomes a light. The adhesion of the penetrating substrate is excellent.

Fig. 3 is a schematic view showing an example of a procedure for simultaneously applying the curable resin composition for the first and second HC layers in the method for producing an optical film of the present invention.

In the light-transmitting substrate 10, the first hard coat layer curable resin composition 60 and the second hard coat layer curable resin composition 70 are respectively used from the slits 51 and 52 of the die coater head 40. And the first hard coat layer curable resin composition is placed on the side of the light-transmitting substrate, and the double-layer coating is applied adjacent to the first hard coat layer to form the first hard coat layer curable resin composition. The coating film 71 and the coating film 71 of the curable resin composition for the second hard coat layer. In addition, in FIG. 3, the curable resin composition for the first hard coat layer and the curable resin composition for the second hard coat layer are integrally formed to form a hard coat layer, but for simplification of description, the two types are used. The composition is separated from its coating film by a color diagram.

Hereinafter, the light-transmitting substrate, the first composition, and the second composition prepared in the steps (i) and (ii) will be described.

(light penetrating substrate)

The light-transmitting substrate of the present invention is not particularly limited as long as it satisfies the physical properties of the light-transmitting substrate which can be used as an optical film, and a conventionally known hard-coated film or optical film can be appropriately selected and used. The cellulose triacetate, polyethylene terephthalate, or cycloolefin polymer used in the medium.

The average light transmittance of the light-transmitting substrate in the visible light region of 380 to 780 nm is preferably 50% or more, more preferably 70% or more, and particularly preferably 85% or more. In addition, the measurement of the light transmittance is carried out by using an ultraviolet-visible spectrophotometer (for example, UV-3100PC manufactured by Shimadzu Corporation), and the values measured at room temperature and in the atmosphere.

Further, the light-transmitting substrate may be subjected to a saponification treatment or a surface treatment such as a primer layer. Further, an additive such as an antistatic agent may be added to the light transmissive substrate.

The thickness of the light-transmitting substrate is not particularly limited, but is usually about 20 μm to 300 μm, preferably 40 μm to 200 μm.

(curable resin composition for the first hard coat layer)

The curable resin composition for the first hard coat layer contains a reactive first resin and a first solvent, and does not contain low refractive index fine particles and a low refractive index resin, or even contains a low refractive index resin. The first resin has a mass of 5.0% by mass or less and a viscosity μ1 of 5 mPa·s or more.

The first composition does not contain the low refractive index fine particles and the low refractive index resin, or the low refractive index resin is 5.0 mass% or less with respect to the mass of the first resin, and has the above specific viscosity, and is described later. The composition contains a low refractive index component and has a specific viscosity, and the two compositions are adjacent to each other in a manner that the first composition is located closer to the side of the light transmissive substrate than the second composition. Simultaneously coating, and when the first composition and the second composition are hardened to form an HC layer, in the film thickness direction of the HC layer, the light is worn from the interface side of the opposite side of the light-transmitting substrate. The transparent substrate side has a distribution in which the low refractive index component gradually decreases, and when the low refractive index component is a low refractive index fine particle, the low refractive index fine particles are distributed as shown in FIG.

The viscosity μ1 of the first composition is preferably 3 mPa ‧ s or more, and more preferably 10 mPa ‧ s or more from the viewpoint of appropriately suppressing mixing between the second composition and the second composition. The viscosity μ1 is preferably 95 mPa·s or less, more preferably 50 mPa·s or less, and particularly preferably 30 mPa·s or less from the viewpoint of improving coatability. Further, the viscosity μ2 of the second composition minus the value of μ1 (hereinafter also referred to as "viscosity difference") is 30 mPa ‧ or less. The viscosity difference is preferably 15 mPa ‧ or less, more preferably 10 mPa ‧ s or less from the viewpoint of suppressing mixing and forming a planar shape. Further, the viscosity μ1 of the first composition and the viscosity μ2 of the second composition are preferably from the viewpoint of coatability, and μ2 is larger than μ1.

Further, the viscosity of the first composition and the second composition described later is, for example, a product name MCR301 manufactured by Anton Paar Co., Ltd., and the measurement jig is set to PP50, and the measurement temperature is 25 ° C, and the shear rate is 10000 [l/s. The conditions of the measurement object can be measured by dropping an appropriate amount of the composition of the measurement object onto the platform.

The first composition does not contain the low refractive index fine particles and the low refractive index resin, or is contained in the low refractive index resin at 5.0 mass% or less based on the mass of the first resin. Such a low refractive index component is preferably present only in the interface of the HC layer on the opposite side of the light transmissive substrate and its vicinity from the viewpoint of exhibiting antireflection performance. When the low refractive index component in the entire HC layer is uniformly present, the antireflection performance of the optical film is not sufficiently exhibited, and the hardness of the HC layer may not be sufficiently exhibited. In this regard, the second composition described later has a function of distributing a plurality of low refractive index components to the interface and its vicinity. Even if the first composition contains a low refractive index resin, if it is in the above amount, the optical film can still obtain sufficient antireflection performance. The amount of the low refractive index resin contained in the first composition is preferably 1% by mass or less based on the mass of the first resin.

(first resin)

The first resin is reactive and hardened to become a component of the HC layer matrix. The first resin has a polymerization or crosslinking reactivity between the first resin and the second resin described later by irradiation with light or heating. The first resin may be a photocurable resin which is cured by light irradiation such as ultraviolet rays, or may be a thermosetting resin which is cured by heating.

In the case of the first resin-based photocurable resin, the first resin preferably has a polymerizable unsaturated group, and more preferably has an epitaxial radiation-curable unsaturated group. Specific examples thereof include an ethylenically unsaturated bond such as a (meth)acryl fluorenyl group, a vinyl group, and an allyl group, and an epoxy group.

In the case of the first resin-based thermosetting resin, the first resin may have, for example, a hydroxyl group, a carboxyl group, an amine group, an epoxy group, a glycidyl group, an isocyanate group, and an alkoxy group.

The first resin system preferably has two or more reactive groups per molecule, and more preferably three or more, from the viewpoint of improving the hardness of the HC layer by the crosslinking reaction.

The first resin of the photocurable resin may be a photocurable resin which is known to be an HC layer substrate, and preferably, for example, pentaerythritol triacrylate (PETA) and dipentaerythritol hexaacrylate (DPHA) are used. Polyfunctional monomer.

For the first resin of the thermosetting resin, for example, a compound having an epoxy group and a binder epoxy compound described in JP-A-2006-106503 can be used. Further, a thermosetting resin described in JP-A-2008-165041 can also be used.

From the viewpoint that the viscosity of the first composition μ1 is relatively easy to adjust, the molecular weight of the first resin is preferably 500 or more, more preferably more than 1,000. Further, from the viewpoint that the first composition viscosity μ1 is easily adjusted, the upper limit of the molecular weight of the first resin is preferably 150,000 or less, more preferably 50,000 or less, and particularly preferably 20,000 or less. By setting the molecular weight of the first resin within this range, it is possible to suppress the low refractive index fine particles or the low refractive index resin contained in the second composition described later, and it is uniformly diffused in the entire HC layer, and it is easy to make it large. Most of them exist on the interface side of the HC layer on the opposite side of the light-transmitting substrate.

The resin having a molecular weight of more than 1,000 is preferably, for example, a polymer D containing a polyalkylene oxide chain described in Patent Document 1, or a product name BEAMSET DK1 manufactured by Arakawa Chemical Industry Co., Ltd., manufactured by Shin-Nakamura Chemical Industry Co., Ltd. The trade name is NH oligo U-15HA, which is a UV-curable urethane acrylate oligomer, and the trade name UV-1700B manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

From the viewpoint of suppressing occurrence of interference fringes at the interface between the HC layer and the substrate, it is preferable to contain a resin having a molecular weight of 1,000 or less in the first resin. Such a resin having a molecular weight of 1,000 or less is preferably a PETA or DPHA as described above.

When the first resin is used in combination with a resin having a molecular weight of 1,000 or less and a resin other than the above (that is, a resin having a molecular weight of more than 1,000), the resin content of the molecular weight of 1,000 or less may be appropriately adjusted by blending the desired viscosity or the like. The resin content of the molecular weight of 1,000 or less is preferably from 50 to 100% by mass based on the total mass of the first resin.

Further, from the viewpoint of the hardness of the HC layer, the molecular weight of the first resin is preferably 5,000 or less.

Further, for the first resin, for example, the binder C described in Patent Document 1 can be used. The commercially available product of the binder C is commercially available as a urethane acrylate having a weight average molecular weight of less than 10,000 and having 2 or more polymerizable unsaturated groups, such as a product name AH manufactured by Kyoei Corporation Chemical Co., Ltd. -600, AT-600, UA-306H, UA-306T, UA-3061, etc.; Japan Synthetic Chemical Industry Co., Ltd. trade name UV-3000B, UV-3200B, UV-6300B, UV-6330B, UV-7000B, etc. ; Arakawa Chemical Industry Co., Ltd. trade name BEAMSET 500 series (502H, 504H, 550B, etc.); New Nakamura Chemical Industry Co., Ltd. trade name U-6HA, UA-32P, U-324A; East Asia Synthetic (share) system Trade name M-9050 and so on.

The content of the first resin may be used after being appropriately adjusted, and the total solid content of the first composition is preferably 40 to 90% by mass, more preferably 50 to 80% by mass.

The first resin may be used singly or in combination of two or more. Further, the first resin may be the same as or different from the basic skeleton, the functional group type, or the number of functional groups or molecular weight of the second resin contained in the second composition described later.

(first solvent)

The first solvent has a function of adjusting the viscosity by dissolving or dispersing the solid portion of the first resin as in the first composition.

The first solvent is one or two or more selected from the solvents used in the conventional composition for a hard coat layer. For example, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), toluene, etc.; or alcohols, ketones, esters, halogenated hydrocarbons, aromatic hydrocarbons, etc., as described in JP-A-2005-316428, Ethers, etc. In addition to this, the first solvent can be used, for example, tetrahydrofuran, 1,4-two An ether such as an alkane, a dioxolane or a diisopropyl ether; and a glycol such as methyl glycol, propylene glycol monomethyl ether (PGME) or methyl glycol acetate.

From the viewpoint of adjusting (increasing) the viscosity of the first composition, the first solvent preferably has a high viscosity, preferably 1 mP·s or more, more preferably 2 mP·s or more. Such a solvent for increasing the viscosity of the first composition is preferably propylene glycol monomethyl ether (PGME) or the like.

Further, the first solvent also has a function of allowing a part of the first resin to permeate into the light-transmitting substrate by appropriately selecting the type of the first solvent and the type of the light-transmitting substrate.

In the present invention, by using (or using) a solvent 1 (permeable solvent) having permeability to a light-transmitting substrate, it is possible to easily suppress the occurrence of interference fringes in the first resin penetrating into the substrate. It can also improve the adhesion.

Further, the term "permeability" as used in the present invention means a property of permeating a light-transmitting substrate, and further encompasses the concept of swelling or wetting a light-transmitting substrate.

Specific examples of the osmotic solvent include ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as methyl acetate, ethyl acetate and butyl acetate; and halogenated hydrocarbons and phenols.

The solvent used in the case where the light-transmitting substrate is cellulose triacetate (TAC), and the solvent used in the case where the light-transmitting substrate is polyethylene terephthalate (PET). There is a solvent described in JP-A-2005-316428.

In particular, the solvent used in the case where the light-transmitting substrate is cellulose triacetate (TAC) is preferably methyl acetate, ethyl acetate, butyl acetate, and methyl ethyl ketone.

The first solvent may be the same as or different from the second solvent contained in the second composition described later.

In the first composition, the mass ratio of the first resin is 100 to 400% by mass based on the mass of the first solvent, and is formed on the opposite side of the light-transmitting substrate from the HC layer. The viewpoint of the distribution of the low refractive index component is preferred. Moreover, in this case, in the second composition described later, the total mass ratio of the low refractive index component and the second resin is 100 to 400% by mass based on the mass of the second solvent.

(Other components of the curable resin composition for the first hard coat layer)

In addition to the above components, the first composition may contain, for example, a polymerization initiator, an antistatic agent, a tackifier, and a reactive or non-reactive coating agent, etc., for the purpose of imparting functionality.

(polymerization initiator)

A radical and a cationic polymerization initiator may be appropriately selected as needed. These polymerization initiators are decomposed by light irradiation and/or heating to generate radicals or cations, and are subjected to radical polymerization and cationic polymerization. The radical polymerization initiator may, for example, be IRGACURE 184 (1-hydroxy-cyclohexyl-phenyl-ketone) manufactured by Ciba.

When a photocationic polymerizable first resin is used as in the case of the first resin containing an epoxy group, for example, a cationic polymerization initiator described in JP-A-2010-107823 can be used.

When a polymerization initiator is used, the content thereof is preferably from 1 to 10% by mass based on the total solid content of the first composition.

(antistatic agent)

For the antistatic agent, a conventionally known antistatic agent can be used, and for example, a cationic antistatic agent such as a quaternary ammonium salt described in JP-A-2007-264221, or tin-doped indium oxide (ITO) or the like can be used. Microparticles.

When the antistatic agent is used, the content thereof is preferably from 30 to 60% by mass based on the total solid content of the first composition.

(tackifier)

In the first composition, a tackifier may also be contained for the purpose of viscosity adjustment.

As the tackifier, a conventionally known tackifier can be used, and examples thereof include protein systems such as casein and casein salts; polyvinyl alcohol, aliphatic guanamine, acrylic acid copolymer, polyvinylpyrrolidone, sodium polyacrylate, and the like. A polyether dialkyl ester, a partial ester of a vinyl methyl ether-maleic anhydride copolymer, and an organic tackifier such as acetylene glycol. Other examples include inorganic tackifiers such as micro-cerium oxide, kaolin, bentonite and talc.

The organic tackifier and the inorganic tackifier may be used singly or in combination of two or more.

When a tackifier is used, the content thereof is preferably 0.1 to 10% by mass based on the total solid content of the first composition.

(average paint)

The leveling agent has an effect of imparting such properties as coating stability, slipperiness, antifouling property or scratch resistance to the surface of the HC.

As the leveling agent, a leveling agent such as a fluorine-based, polyfluorene-based or acrylic-based one which is conventionally used for an antireflection film can be used. Can be used arbitrarily, for example: DIC (share) system MEGAFAC A fluorine-based coating agent having no free radiation curable group such as a series (MCF350-5) or a polyfluorene-based coating agent having an exothermic radiation curable group such as X22-163A manufactured by Shin-Etsu Chemical Co., Ltd.

When the content of the coating agent is a fluorine-based coating agent, it is used in an amount of 5.0% by mass or less, preferably 0.1 to 3.0% by mass, based on the mass of the first resin, and a coating agent other than the fluorine-based coating agent. In other cases, it is preferable to use 0.5 to 10% by mass based on the mass of the first resin.

In addition, the coating agent content is preferably 5.0% by mass or less based on the total mass of the solid content of the first composition and the second composition from the viewpoint of the hardness of the HC layer.

The first composition is usually prepared by mixing a first resin and other polymerization initiators as necessary in a first solvent in accordance with a general preparation method and performing a dispersion treatment. A paint shaker or a bead mill or the like can be used for mixing and dispersing.

(curable resin composition for second hard coat layer)

The curable resin composition for a second hard coat layer used in the method for producing an optical film of the present invention contains one selected from the group consisting of low refractive index fine particles having an average particle diameter of 10 to 300 nm and a low refractive index resin. The above low refractive index component has a reactive second resin and a second solvent, and has a viscosity μ2 of 5 mPa·s or more and a viscosity difference of 30 mPa·s or less.

The second composition contains a low refractive index component having the above specific viscosity, and the two components are adjacent to each other in such a manner that the first composition is located closer to the light transmissive substrate than the second composition. Simultaneous coating is performed to form an interface between the opposite sides of the light-transmitting substrate in the film thickness direction of the HC layer when the first composition and the second composition are hardened to form an HC layer. The side of the light-transmissive substrate side has a distribution in which the low refractive index component gradually decreases. When the low refractive index component is a low refractive index fine particle, the low refractive index fine particles are distributed as shown in FIG.

The viscosity μ2 of the second composition used in the method for producing an optical film of the present invention is preferably 5 mPa ‧ or more, more preferably 10 mPa ‧ s or more from the viewpoint of moderately suppressing mixing with the first composition . The viscosity μ2 is preferably 100 mPa·s or less, more preferably 50 mPa·s or less, and particularly preferably 30 mPa·s or less from the viewpoint of improving coatability. Further, the viscosity μ1 of the first composition and the viscosity μ2 of the second composition are preferably μ2 larger than μ1 from the viewpoint of coatability.

(low refractive index microparticles)

The low refractive index microparticles used in the method for producing a first optical film of the present invention impart resistance to the optical film of the present invention by most of the interface side of the HC layer which is on the opposite side of the light transmissive substrate. Reflective. In addition to the low refractive index fine particles, a low refractive index resin described later can be used in combination.

The low refractive index microparticles refer to those having a refractive index of 1.20 to 1.45.

For the low-refractive-particles, the particles used in the conventionally known low-refractive-index layer can be used, and examples thereof include hollow cerium oxide fine particles described in Patent Document 2, LiF (refractive index 1.39), and MgF ₂ (magnesium fluoride, Metal fluoride fine particles such as a refractive index of 1.38), AlF ₃ (refractive index of 1.38), Na ₃ AlF ₆ (cryolite, refractive index of 1.33), and NaMgF ₃ (refractive index of 1.36).

Further, the low refractive index fine particles may be subjected to a crosslinking reaction with the second resin or the first resin, or may be coated with an organic component having a polymerizable unsaturated group or a thermosetting group. For the method of coating, a method of preparing reactive inorganic fine particles described in JP-A-2008-165040 can be used.

The average particle diameter of the low refractive index fine particles is set to be 300 nm or less from the viewpoint of preventing the fog value of the HC layer from rising. In the case of the low refractive index fine particles hollow cerium oxide fine particles, since the voids are required, the average particle diameter is 10 nm or more from the viewpoint of exhibiting the effect of lowering the refractive index.

The average particle diameter of the low refractive index fine particles is preferably from 10 to 100 nm, more preferably from 30 to 100 nm.

The content of the low refractive index fine particles can be used as long as it is appropriately adjusted, and is preferably from 50 to 90% by mass, and more preferably from 65 to 90% by mass, based on the total mass of the second resin contained in the second composition.

(low refractive index resin)

The low refractive index resin refers to a resin having a refractive index of 1.30 to 1.45 after being formed into a film. In addition to the low refractive index resin, the above low refractive index fine particles may be used in combination.

In addition, since the low refractive index resin is a component which can become a part of the HC layer matrix after the coating film is formed, it is also possible to use a low refractive index resin as a second resin to be described later.

As the low refractive index resin, a fluorine-containing resin having a reactive group such as a photocurable group or a thermosetting group, a fluorine-containing resin having no reactive group, or the like can be used.

The fluorine-containing resin having a photocurable group may, for example, be vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluorobutadiene or perfluoro-2,2-dimethyl-1,3-di A fluorinated olefin such as azole.

Other fluorine-containing resins having a photocurable group include, for example, (meth)acrylic acid-2,2,2-trifluoroethyl ester, (meth)acrylic acid-2,2,3,3,3-pentafluoro. Propyl ester, 2-(perfluorobutyl)ethyl (meth)acrylate, 2-(perfluorohexyl)ethyl (meth)acrylate, 2-(perfluorooctyl) (meth)acrylate a (meth) acrylate compound such as ethyl ester, 2-(perfluorodecyl)ethyl (meth)acrylate, methyl α-trifluoromethyl methacrylate or ethyl α-trifluoromethyl acrylate; 1 molecule a fluorine-containing polyfunctional group containing at least three fluorine atoms having a fluorinated alkyl group having 1 to 14 carbon atoms, a fluorocycloalkyl group or a fluorinated alkyl group, and at least 2 (meth) propylene fluorenyl groups ( A methyl acrylate compound or the like.

As the fluorine-containing resin having a thermosetting group, for example, a 4-fluoroethylene-perfluoroalkyl vinyl ether copolymer, a vinyl fluoride-hydrocarbon vinyl ether copolymer, an epoxy resin, a polyurethane resin, or the like can be used. Fluorine modified materials such as cellulose resin, phenol resin and polyimine resin.

A polymer or a copolymer of a fluorine atom-containing polymerizable compound described in JP-A-2010-122603, and a polyfluorene-containing vinylidene fluoride copolymer may be used.

The molecular weight of the low refractive index resin is not particularly limited and may be appropriately selected, but it is preferably from 500 to 5,000 from the viewpoint of adjusting the viscosity of the second composition.

The content of the low refractive index resin contained in the second composition may be appropriately adjusted, and when the low refractive index resin has the second resin described later, it is preferably the total solid content of the second composition. It is 70 to 100% by mass.

(second resin)

The second resin is a component which is reactive and hardens to form a matrix of the HC layer. The second resin has a polymerization or crosslinking reactivity between the second resins and the first resin by light irradiation or heating.

The second resin may be a photocurable resin which is cured by light irradiation such as ultraviolet rays, or may be a thermosetting resin which is cured by heating. In the case of the second resin-based photocurable resin, the second resin preferably has a polymerizable unsaturated group, and more preferably has an epitaxial radiation-curable unsaturated group. Specific examples thereof include an ethylenically unsaturated bond such as a (meth)acryl fluorenyl group, a vinyl group, and an allyl group, and an epoxy group.

In the case of the second resin-based thermosetting resin, the thermosetting group of the second resin may, for example, be a hydroxyl group, a carboxyl group, an amine group, an epoxy group, a glycidyl group, an isocyanate group, or an alkoxy group. Wait.

The second resin is preferably one or more curable groups per molecule, and more preferably three or more, from the viewpoint of improving the hardness of the HC layer by the crosslinking reaction.

As the second resin, those exemplified in the above first resin can be used.

The content of the second resin is preferably 60% by mass or less based on the total solid content of the second composition as long as it is appropriately adjusted and used, and when the second resin has a low refractive index resin, The total solid content of the second composition may be 100% by mass or less.

The second resin may be used singly or in combination of two or more.

(second solvent)

The second solvent has a function of adjusting the viscosity by dissolving or dispersing a solid portion such as the above-mentioned low refractive index fine particles or the second resin in the second composition. As the second solvent, those exemplified in the above first solvent can be used.

(Other components of the curable resin composition for the second hard coat layer)

The second composition may further contain, for example, a polymerization initiator, an antistatic agent, a tackifier, an antifouling agent, and a reaction, in addition to the above components, for the purpose of imparting functionality, like the first composition. Sexual or non-reactive uniform paint and the like.

(polymerization initiator)

As the polymerization initiator, those exemplified in the above first composition can be used.

When a polymerization initiator is used, the content is preferably from 1 to 5% by mass based on the total solid content of the second composition.

(antistatic agent)

As the antistatic agent, those exemplified in the above first composition can be used.

When the antistatic agent is used, the content is preferably from 30 to 60% by mass based on the total solid content of the second composition.

(tackifier)

The tackifier can be exemplified by the above first composition. The content of the tackifier is preferably from 0.1 to 10% by mass based on the total solid content of the second composition.

(antifouling agent)

The antifouling agent prevents the outermost surface of the optical film from being soiled, and also imparts scratch resistance to the HC layer. The antifouling agent can be contained in both the first composition and the second composition. The antifouling agent is preferably contained only in the second composition from the viewpoint that the antifouling property can be effectively exhibited in a small amount.

As the antifouling agent, an antifouling agent (antifouling agent) such as a fluorine-based compound or a lanthanoid compound known in the art can be used.

The antifouling agent is, for example, an antifouling agent described in JP-A-2007-264279.

It is preferable to use a commercially available antifouling agent. The antifouling agent (non-reactive) of such a commercially available product is, for example, MEGAFAC manufactured by DIC Co., Ltd. Series such as: trade name MCF350-5, F445, F455, F178, F470, F475, F479, F477, TF1025, F478 and F178K, etc.; TOSHIBA SILICONE (share) system TSF series, etc.; Shin-Etsu Chemical Industry Co., Ltd. X-22 Series and KF series, etc.; and CHIASO (share) system Silaplane Series, etc.

For the antifouling agent (reactivity) of the commercially available product, for example, the brand name SUA1900L10 and the brand name SUA1900L6 manufactured by Shin-Nakamura Chemical Industry Co., Ltd.; the product name Ebecry 1350, the product name Ebecry 11360, and the trade name KRM7039 manufactured by Daicel UCB Co., Ltd. KI3971 manufactured by Japan Synthetic Chemical Industry Co., Ltd.; DIFENSA TF3001, trade name DIFENSA TF3000 and trade name DIFENSA TF3028 under DIC (share); LIGHT-PROCOAT AFC3000 under the trade name of Coron Chemical Co., Ltd.; Shin-Etsu Chemical Industry ( The product name is KNS5300; the GE TOSHIBA SILICONE (stock) product name is UVHC1105 and UVHC8550; and the Japanese paint (stock) product name is ACS-1122 and so on.

(average paint)

As the leveling agent, those exemplified in the above first composition can be used.

The leveling agent can be contained in both the first composition and the second composition. From the viewpoint of exhibiting a uniform coating function from the viewpoint of efficiency, it is preferable to contain only the second composition.

In the case of using a leveling agent, in the case of a fluorine-based leveling agent, it is used in an amount of 5.0% by mass or less, preferably 0.1% to 3.0% by mass based on the mass of the second resin, and a coating agent other than the fluorine-based coating agent. In other cases, it is preferably 0.5 to 10% by mass based on the mass of the second resin.

The method of preparing the second composition can be carried out by the method exemplified in the above first composition.

(other functional layer composition)

In the method for producing an optical film of the present invention, in the step of simultaneously coating (iii), at least one of the first and second compositions may be applied simultaneously on one surface side of the light-transmitting substrate. In combination with the performance required for the optical film, other functional layers may be appropriately disposed, and other functional layer compositions may be prepared.

Other functional layers include, for example, an antistatic layer and an antifouling layer.

Further, as will be described later, when the other functional layer component is applied from the side of the light-transmitting substrate in the state in which the first and second components are adjacent to each other, an appropriate coating can be set in accordance with the function. Cloth location.

In the method for producing an optical film of the present invention, in the step of (iii) applying the first composition and the second composition simultaneously, the method of simultaneously applying the first and second compositions can be carried out. On the premise of simultaneous coating, the rest is not particularly limited, and a conventionally known method such as the method using the extrusion type die coater shown in Fig. 3 can be used.

In the step of (iii) applying the first composition and the second composition simultaneously, the wet film thickness of the coating film of the first composition is set to T1, and the second composition is used. When the coating film wetting film thickness is T2, T2/T1 is set to 0.01 to 1, but from the viewpoint of improving the antireflection property of the optical film with high efficiency, it is preferable to have a low refractive index in the film thickness direction of the HC layer. The rate component exists in the interface side of the HC layer on the opposite side of the light transmissive substrate, more on the side of the light transmissive substrate, and on the side of the light transmissive substrate, the low refractive index component exists. The distribution of the smaller amount is gradually decreased from the interface on the opposite side of the light-transmitting substrate toward the side of the light-transmitting substrate, and in the film thickness direction of the hard coat layer, A distribution of 70 to 100% of the total amount of the low refractive index component is present in a region from the interface on the opposite side of the light-transmitting substrate to the dry film thickness of the hard coat layer of 70%. Here, the "wetting film thickness" means the thickness of the coating film in a state before the solvent is volatilized in the composition immediately after application, and the volume/coating area of the composition coated on the light-transmitting substrate. ) can be obtained.

Further, when the coating of the first and second compositions is carried out using a die coating head as shown in FIG. 3, it belongs to the distance between the die coater head 40 and the light-transmitting resin substrate 10. The coating height 80 and the total thickness of the coating film of the first and second compositions at the time of simultaneous multilayer coating on the light-transmitting resin substrate 10 are preferably 90 (the thickness of 90) The relationship between times). By performing simultaneous multi-layer coating while maintaining such a relationship, the coating droplets formed between the light-transmitting resin substrate 10 and the mold coater head 40 are stabilized. In particular, when the coating droplets are formed into a film by coating, the film becomes more unstable, and the coating surface is likely to be spotted or streaked, which causes deterioration in appearance. However, by maintaining the above coating height 80 and thickness The relationship of 90 makes it easy to stabilize the coating droplets. In addition, the "coating droplet" means the liquid retention generated between the coating device and the substrate.

The other functional layer composition may be applied simultaneously with the first and second compositions, or may be additionally applied in addition to the first and second compositions. In the case of simultaneous coating, the coating position can be set in accordance with the function of the first and second compositions in the state of being adjacent to each other from the side of the light-permeable substrate. . For example, when the antistatic layer composition is applied simultaneously with the first and second compositions, it is only on the upstream side of the light transmissive substrate transport direction 140 in the die slit 51 of FIG. 3 (ie, A third slit (not shown) is provided on the left side of the slit 51 in Fig. 3, and the antistatic layer composition and the first and second compositions are simultaneously coated. Further, for example, when the composition for an antistatic layer, the first and second compositions, and the composition for an antifouling layer are simultaneously applied, as long as the antistatic layer is coated on the left side of the slit 51 in FIG. The fourth slit (not shown) for the composition is provided on the right side of the slit 52 as a fourth slit (not shown) for applying the composition for the antifouling layer, and the four compositions can be used. The material is applied at the same time.

The drying method of the step (iv) is, for example, drying under reduced pressure or heating, and a method of combining the drying and the like. Further, when drying is carried out under normal pressure, it is preferred to carry out drying at 30 to 110 °C.

In the present invention, pre-baking is not performed before the step (iv) is performed (i.e., before the coating film is dried).

For example, when the first or second solvent is methyl isobutyl ketone, it is usually carried out at a temperature ranging from room temperature to 80 ° C, preferably from 40 ° C to 70 ° C, for 20 seconds to 3 minutes, preferably 30 seconds. Dry for 1 minute.

Further, in the present invention, the term "drying" in the step (iv) means that even if the drying is performed, the hardening of the layer is not sufficiently performed as a product (for example, the pencil hardness test prescribed in JIS K5600-5-4 (1999). In the case where the first resin and the second resin contain a thermosetting resin, the heating performed after the drying is performed by the use of the 4.9N load. This heating allows the layer to be cured at a temperature sufficient for the product (the hardness "H" or higher in the pencil hardness test described above).

The light irradiation method of the (iv) step mainly uses, for example, ultraviolet rays, visible light, electron beams, or free radiation. In the case of ultraviolet curing, ultraviolet rays emitted from light such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc or a metal halide lamp are used. The irradiation amount of the energy ray source is 50 to 300 mJ/cm ^{2 in} terms of an integrated exposure amount of an ultraviolet wavelength of 365 nm.

In the present invention, the prebaking is not performed, but the light irradiation or heating for hardening (formally hardening) the coating film is carried out after the coating film is dried. Thereby, the low refractive index component contained in the second composition is more likely to penetrate through the light in the film thickness direction of the HC layer than on the opposite side of the opposite side of the light-transmitting substrate of the HC layer. On the side of the substrate, and on the side of the light-transmitting substrate, the distribution of the low refractive index component is less, from the interface on the opposite side of the light-transmitting substrate toward the light-transmitting substrate. The side of the low refractive index component is gradually decreased, and the occurrence of interference fringes caused by the difference in refractive index between the low refractive index component and the resin of the HC layer in the HC layer can be obtained, and the interface between the HC layer and the substrate interferes. An optical film excellent in visibility and excellent in visibility.

Further, since the coating film is dried without performing prebaking, and then the coating film is cured by light irradiation or heating, the HC layer is improved in comparison with the case where the prebaking is performed to harden. The adhesion between the light-transmissive substrate or the HC layer on the side adjacent to the side of the light-transmitting substrate.

Further, since it is not necessary to perform prebaking, it is excellent in productivity in the case where hardening is performed by two-degree light irradiation such as prebaking or main hardening.

(optical film)

The optical film of the present invention is obtained by the above-described production method, and as shown in Fig. 1, at least one HC layer 20 is provided on one surface side of the light-transmitting substrate 10.

The optical film of the present invention is produced by the above-described production method so that the low refractive index fine particles and/or the low refractive index resin contained in the second composition are present in the HC layer in the film thickness direction. The interface side on the opposite side of the light-transmitting substrate is more on the side of the light-transmitting substrate, and the smaller the distribution on the side of the light-transmitting substrate, the less HC can be obtained. The occurrence of interference fringes due to the difference in refractive index between the low refractive index fine particles and/or the low refractive index resin and the resin of the HC layer in the layer, and the interference pattern at the interface between the HC layer and the substrate, and excellent visibility Optical film.

Further, since the coating film is dried without performing prebaking, and then hardened by light irradiation or heating, drying, light irradiation or heating is performed in comparison with the prebaking. In the case of hardening, there is no known case where a low refractive index layer and an HC layer are formed by sequential double layer coating, or a case where simultaneous coating is formed as in Patent Document 2, and a clear layer interface occurs. It has an anti-reflective function, and it can suppress the occurrence of interference fringes between layers while maintaining the fog value, the total light transmittance, and the smear-free surface, and the adhesion is improved, and is increased in the vicinity of the substrate. The ratio of the hard coat composition having the same refractive index as the refractive index of the substrate suppresses the occurrence of interference fringes between the hard coat layer and the substrate, and is excellent in adhesion.

The optical film of the present invention may be coated with other functional layer compositions to form other functional layers as described in the above production method, for example, when antistatic is applied to the light transmissive substrate side of the first composition. When the composition for the layer is formed to form an antistatic layer, as shown in FIG. 4, the antistatic layer 140 and the layer of the HC layer 20 are formed from the side of the light-transmitting substrate 10.

Further, as shown in FIG. 5, the anti-fouling layer 150 may be provided on the surface of the HC layer on the opposite side of the light-transmitting substrate.

The dry film thickness (hereinafter also referred to as "film thickness") of the HC layer can be appropriately adjusted in accordance with the required properties. For example, the film thickness is preferably 1 to 20 μm.

The film thickness of other functional layers can be appropriately adjusted. For example, the film thickness of the antistatic layer is preferably 0.05 to 5 μm, and the film thickness of the antifouling layer is preferably 0.01 to 10 nm.

The optical film of the present invention can adjust the reflectance of the incident light by appropriately adjusting the kind and content of the low refractive index fine particles and the low refractive index resin of the second composition in accordance with the required properties. The reflectance is preferably from 1 to 3.75, more preferably from 1 to 3.4.

The reflectance was obtained by using a spectrophotometer model V7100, a UV-visible spectrophotometer manufactured by JASCO Corporation, and a product of VAR-7010 absolute reflectance, manufactured by JASCO Corporation. The incident angle was set to 5° and the polarizer was set. The N-polarized light and the measurement wavelength range were set to 380 to 780 nm, and a black tape was bonded to the optical film on the side of the TAC substrate, and this was placed in a device and measured. Further, the average value of the measurement results obtained by using the measurement wavelength range is regarded as the reflectance.

The haze value of the optical film of the present invention can be appropriately adjusted in accordance with the desired properties, and is preferably 0.1 to 1.0%, more preferably 0.1 to 0.4%.

The haze value can be measured by a reflection ‧ transmittance meter HM-150 (manufactured by Murakami Color Research Laboratory Co., Ltd.) in accordance with JIS K7136.

In a preferred embodiment of the optical film of the present invention, an optical film having a hard coat layer is provided on one surface side of the light-transmitting substrate, and in the film thickness direction of the hard coat layer, low-refractive-index particles are present in the light. The interface side of the opposite side of the penetrating substrate is more on the side of the light-transmitting substrate, and the smaller the amount of the low-refractive-index particles is on the side of the light-permeable substrate, the less The interface on the opposite side of the light-transmitting substrate faces the light-permeable substrate side, and the low-refractive-index component gradually decreases, and there is no layer interface in the hard coat layer. In the checkerboard adhesion test of the penetrating substrate, the adhesion ratio can be made 90 to 100%.

As shown in FIG. 1, by forming such a distribution of low-refractive-index microparticles in the HC layer, it has an anti-reflection function, and suppresses interlayers while maintaining a haze value, a total light transmittance, and a speckle-free surface. The interference pattern is generated to improve the adhesion, and the ratio of the hard coating composition having the same refractive index as the refractive index of the substrate is increased in the vicinity of the substrate, thereby suppressing the occurrence of interference fringes between the hard coat layer and the substrate. An optical film excellent in adhesion can be obtained.

The term "layer interface in the hard coat layer" means that an interface (boundary) occurs in the hardened portion of the composition in the layer as shown in Fig. 2 . Specific examples of the layer interface include the boundary of the hardened portion of the two compositions shown in Table 3 (c) to be described later.

In a preferred embodiment of the optical film of the present invention, in the film thickness direction of the hard coat layer, the dry film thickness of the hard coat layer is 70 from the interface on the opposite side of the light-transmitting substrate. In the region up to %, 70 to 100% of the total amount of the low refractive index fine particles are present. Thereby, the antireflection property of the optical film can be improved efficiently.

The total light transmittance (τt) of the optical film of the present invention is preferably 90% or more, and more preferably 92% or more from the viewpoint of transparency.

The total light transmittance of the optical film can be measured by using a measuring instrument having the same haze value according to JIS K7361.

(polarizer)

The polarizing plate of the present invention is characterized in that a polarizing plate is provided on the side of the optical film opposite to the light-transmitting substrate of the hard coat layer.

Fig. 6 is a view showing an example of the layer constitution of the polarizing plate of the present invention. The polarizing plate 2 shown in FIG. 6 includes an optical film 1 in which the HC layer 20 is provided on the light-transmitting substrate 10, and a polarizing plate 180 in which the protective film 160 and the polarizing layer 170 are laminated, and the optical film 1 is placed on the optical film 1. A polarizer 180 is provided on the opposite side of the light-transmitting substrate 10 of the HC layer 20.

Further, a polarizing plate is disposed on the side of the optically-transparent substrate on which the optical film is opposed to the hard coat layer, and not only the optical film and the polarizer are formed separately, but also the member constituting the optical film and the polarizer are formed. The condition of the components.

Further, in the case where the polarizing plate of the present invention is used for a display panel, the display panel is usually disposed on the side of the polarizer.

Further, the related optical film is not described here because the above optical film can be used. Hereinafter, other configurations of the polarizing plate of the present invention will be described.

(polarizer)

The polarizer used in the present invention is not particularly limited as long as it has a predetermined polarizing property, and a polarizer generally used in a liquid crystal display device can be used.

The polarizer is in a form in which a predetermined polarizing characteristic is maintained for a long period of time, and the rest is not particularly limited. For example, the polarizing layer may be formed only by a polarizing layer, or the protective film may be bonded to the polarizing layer. When the protective film and the polarizing layer are bonded together, a protective film may be formed only on one surface of the polarizing layer, or a protective film may be formed on both surfaces of the polarizing layer.

The polarizing layer is usually one which can be used to form iodine in a film composed of polyvinyl alcohol, and then to form a complex of polyvinyl alcohol and iodine by uniaxial stretching.

Further, the protective film is not particularly limited as long as it can protect the above-mentioned polarizing layer and has desired light transmittance.

The light transmittance of the protective film is preferably 80% or more, more preferably 90% or more in the visible light region.

Further, the transmittance of the above protective film can be measured in accordance with JIS K7361-1 (Test method for total light transmittance of plastic-transparent material).

The resin constituting the protective film may, for example, be a cellulose derivative, a cycloolefin resin, polymethyl methacrylate, polyvinyl alcohol, polyimide, polyarylate or polyethylene terephthalate. Among them, a cellulose derivative or a cycloolefin resin is preferably used.

The protective film may be composed of a single layer or a plurality of layers. Further, in the case where the protective film is laminated by a plurality of layers, a plurality of laminated layers of the same composition may be used, and a plurality of laminated layers having different compositions may also be used.

Furthermore, the thickness of the protective film is such that the flexibility of the polarizing plate of the present invention can be formed within a desired range, and by conforming with the polarizing layer, the dimensional change of the polarizing plate can be limited to a predetermined range. The remainder is not particularly limited, but is preferably in the range of 5 to 200 μm, more preferably in the range of 15 to 150 μm, and particularly preferably in the range of 30 to 100 μm. If the thickness is thinner than 5 μm, there is a possibility that the dimensional change of the polarizing plate of the present invention becomes large. Further, when the thickness is thicker than 200 μm, for example, when the polarizing plate of the present invention is subjected to cutting, there is a possibility that the processing chips are increased or the wear of the cutting blade is increased.

The protective film may also be of phase difference. By using a phase difference protective film, there is an advantage that the polarizing plate of the present invention forms the viewing angle compensation function of the display panel.

The protective film has a phase difference, and the rest is not particularly limited insofar as it exhibits a desired phase difference. Such a pattern is such that the protective film has a single layer and contains an optical developing developer which exhibits phase difference, and has a phase difference, and a protective film composed of the above resin. In the above, a phase difference layer containing a refractive index anisotropic compound is laminated, whereby phase difference is obtained. In the present invention, any of these aspects is suitable for use.

(monitor)

The display of the present invention is characterized in that a display panel is disposed on the side of the optical film facing the light-transmitting substrate facing the hard coat layer.

Examples of the display include LCD, PDP, ELD (organic EL, inorganic EL), CRT, and the like.

The display is composed of a display panel of a viewer side member of the display and a back side member including a driving portion. In the case where the liquid crystal display is described as an example, the "display panel" is a member composed of two glass plates (for example, a color filter substrate and an array substrate) that block liquid crystal material, a polarizing plate, and an optical film of the present invention. In the case where the liquid crystal display is described as an example, the "back side member" is a member composed of a light source called "backlight", a drive circuit for controlling the LCD, a circuit for controlling the light source, and a casing. In this case, a layer configuration of a liquid crystal display includes a backlight unit such as a light guide plate or a diffusion film, and a polarizing plate, an array substrate, a liquid crystal layer, a color filter substrate, and a polarizing plate are sequentially laminated on the viewer side. And an optical film.

The PDP of another example of the above display includes a front glass substrate and a rear glass substrate. The back glass substrate is disposed in a state in which a discharge gas is sealed between the surface glass substrate and the surface glass substrate. In the case where the display is a PDP, the optical film may be provided on the surface of the surface glass substrate or on the front panel (glass substrate or film substrate).

The display device may be, for example, an ELD device that vaporizes a light-emitting body such as zinc sulfide or a diamine substance that emits light when a voltage is applied, and controls the voltage applied to the substrate to be displayed on the glass substrate, or A display such as a CRT that converts an electronic signal into light to produce an image that is visible to the naked eye. In this case, the above optical film is provided on the surface of the ELD device or the outermost surface of the CRT or the front panel thereof.

[Examples]

Hereinafter, the present invention will be further described by way of examples. The above description does not limit the invention.

The low-refractive-index microparticles are hollow cerium oxide microparticles (trade name: THRULYA) DAS (average particle diameter: 50 nm, MIBK dispersion, solid content: 20%).

The first resin (1) was manufactured by Arakawa Chemical Industry Co., Ltd. under the trade name BEAMSET DK1 (weight average molecular weight: 20,000, solid content: 75%, MIBK solvent).

The first resin (2) is a pentaerythritol triacrylate manufactured by Nippon Kayaku Co., Ltd.

The low refractive index resin having the first resin is LINC-3A manufactured by Kyoei Chemical Co., Ltd. (trimethylidene-heptadecafluorodecenyl-pentaerythritol (main component) represented by the following general formula (1) , a mixture with pentaerythritol triacrylate).

[Chemical 1] General formula (1)

The polymerization initiator was manufactured by Nippon Ciba (trade name) under the trade name IRGACURE (Irg) 184.

The coating agent was a trade name of MCF350-5 (solid content: 5%) manufactured by DIC.

The solvent used MIBK.

As the light-transmitting substrate, a TAC substrate made of Fujifilm Co., Ltd., trade name: TD80UL (thickness: 80 μm) was used.

Further, the viscosity of the first composition and the second composition was measured using MCR301 manufactured by Anton Paar Co., Ltd. under the conditions of a measurement jig of PP50, a measurement temperature of 25 ° C, and a shear rate of 10000 [l/s]. The composition (ink) was dropped on the platform in an appropriate amount and measured.

The measurement of the dry film thickness was carried out by placing a sample of the measurement target on a glass using a product name DIGIMATIC INDICATOR CODE 215-403 manufactured by Mitutoyo.

The abbreviations for each compound are as follows:

PETA: pentaerythritol triacrylate

MIBK: methyl isobutyl ketone

IPA: isopropanol

TAC: triethylenesulfonyl cellulose

(Preparation of curable resin composition for first hard coat layer)

The curable resin compositions 1 and 2 for the first hard coat layer and the curable resin composition 1 for the second hard coat layer were prepared by blending the following components.

(curable resin composition for the first hard coat layer 1)

BEAMSET DK1: 64.72 parts by mass (48.54 parts by mass)

Irg184: 1.94 parts by mass

MCF350-5: 0.97 parts by mass (0.05 parts by mass of solid content)

MIBK: 32.36 parts by mass

(curable resin composition for the first hard coat layer 2)

PETA: 75.49 parts by mass (56.62 parts by mass of solid content)

Irg184: 3.02 parts by mass

MCF350-5: 3.02 parts by mass (0.15 parts by mass of solid content)

MIBK: 18.47 parts by mass

(curable resin composition for the second hard coat layer 1)

THRULYA DAS: 75.81 (15.16 parts by mass)

BEAMSET DK 1:13.48 parts by mass (10.11 parts by mass)

Irg184: 0.61 parts by mass

MCF350-5: 10.11 parts by mass (0.51 parts by mass)

(Curable resin composition 2 for second hard coat layer)

THRULYA DAS: 83.12 (16.62 parts by mass of solid content)

BEAMSET DK 1:15.83 parts by mass (11.87 parts by mass)

Irg184: 0.48 parts by mass

MCF350-5: 0.57 parts by mass (0.03 parts by mass of solid content)

(Curable resin composition for the second hard coat layer 3)

THRULYA DAS: 73.95 (solid content conversion 14.79 parts by mass)

BEAMSET DK1: 24.65 parts by mass (solid content conversion 18.49 parts by mass)

Irg184: 0.74 parts by mass

MCF350-5: 0.67 parts by mass (0.03 parts by mass of solid content)

(Curable resin composition for the second hard coat layer 4)

LINC-3A: 78.63

Irg184: 3.15 parts by mass

MCF350-5: 15.73 parts by mass (0.79 parts by mass of solid content)

MIBK: 2.49 parts by mass

(production of optical film) (Example 1)

The curable resin composition 1 for the first hard coat layer 1 and the curable resin composition 1 for the second hard coat layer were distilled off using an evaporator, and the viscosity was adjusted to 30 mPa·s. Next, the curable resin composition 1 for the first hard coat layer and the curable resin composition 1 for the second hard coat layer are used from the TAC substrate side on the TAC substrate (TD80UL) which is conveyed at a speed of 1 m/min. The positional relationship is applied in two layers at the same time. In this case, the wet film thickness of the coating film of the curable resin composition 1 for the first hard coat layer 1 and the curable resin composition 1 for the second hard coat layer is set to 20 μm and 10 μm, respectively.

Then, the coating film which was simultaneously coated by the double layer was dried at 70 ° C for 60 seconds, and the ultraviolet ray was irradiated with an integrated luminous flux of 120 mJ/cm ² in a nitrogen atmosphere to cure the coating film. An optical film was obtained by forming a hard coat layer having a dry film thickness of 10 μm.

(Comparative Example 1)

In the first embodiment, the curable resin composition 1 for the second hard coat layer was not used, and only the curable resin composition 1 for the first hard coat layer was applied by a wetting film thickness of 20 μm to form a dried film. An optical film was produced in the same manner as in Example 1 except that the hard coat layer was 9 μm thick.

(Comparative Example 2)

In the first embodiment, the curable resin composition 1 for the first hard coat layer was not used, and only the curable resin composition 1 for the second hard coat layer was applied by a wetting film thickness of 20 μm to form a dried film. An optical film was produced in the same manner as in Example 1 except that the hard coat layer was 10 μm thick.

(Comparative Example 3)

In the first embodiment, only the curable resin composition 1 for the first hard coat layer was applied by a wetting film thickness of 20 μm, and the coating film was dried at 70 ° C for 60 seconds, and then under a nitrogen atmosphere. The coating film is cured by irradiation with an ultraviolet light having an integrated luminous flux of 120 mJ/cm ² , and then only the curable resin composition 1 for the second hard coat layer is applied to the cured film at a thickness of 10 μm. After coating, the coating film was dried at 70 ° C for 60 seconds, and then irradiated with ultraviolet light in an atmosphere of 120 mJ/cm ² in a nitrogen atmosphere to cure the coating film to form a total dried film thickness of 10 μm. An optical film was produced in the same manner as in Example 1 except for the hard coat layer.

(Example 2)

The curable resin composition 1 for the first hard coat layer and the curable resin composition 2 for the second hard coat layer were each adjusted to have a viscosity of 10 mPa ‧ s. Then, the curable resin composition 1 for the first hard coat layer and the curable resin composition 2 for the second hard coat layer are used from the TAC substrate side on the TAC substrate (TD80UL) which is transported at a speed of 20 m/min. The positional relationship is applied in two layers at the same time. In this case, the wet film thickness of the coating film of the curable resin composition 1 for the first hard coat layer 1 and the curable resin composition 2 for the second hard coat layer is set to 25 μm and 5 μm, respectively.

Then, the coating film which was simultaneously coated by the double layer was dried at 70 ° C for 60 seconds, and the ultraviolet ray was irradiated so as to have an integrated luminous flux of 120 mJ/cm ² in a nitrogen atmosphere to cure the coating film. A hard coat layer having a dry film thickness of 11 μm was formed to prepare an optical film.

(Example 3)

In the second embodiment, the wet film thickness of the coating film for the first hard coat layer curable resin composition 1 and the second hard coat layer curable resin composition 2 is set to 25 μm and 1 μm, respectively. An optical film was produced in the same manner as in Example 2 except that a hard coat layer having a dry film thickness of 8 μm was formed.

(Example 4)

In the second embodiment, the wet film thickness of the coating film for the first hard coat layer curable resin composition 1 and the second hard coat layer curable resin composition 2 was set to 18.75 μm and 3.75, respectively. An optical film was produced in the same manner as in Example 2 except that a hard coat layer having a dry film thickness of 6 μm was formed in μm.

(Comparative Example 4)

In the second embodiment, the curable resin composition 2 for the second hard coat layer was not used, and only the curable resin composition 1 for the first hard coat layer was applied by a wetting film thickness of 20 μm to form a dried film. An optical film was produced in the same manner as in Example 2 except that the hard coat layer was 11 μm thick.

(Comparative Example 5)

In the second embodiment, the curable resin composition 1 for the first hard coat layer was not used, and only the curable resin composition 2 for the second hard coat layer was applied by a wetting film thickness of 10 μm to form a dried film. An optical film was produced in the same manner as in Example 2 except that the hard coat layer was 5 μm thick.

(Comparative Example 6)

In the second embodiment, after the first hard coat layer curable resin composition 1 and the second hard coat layer curable resin composition 2 are applied, the film is applied before the drying, before the drying. An optical film was produced in the same manner as in Example 2 except that the ultraviolet light was irradiated (prebaked) so that the integrated luminous flux was 50 mJ/cm ² .

(Example 5)

The curable resin composition 1 for the first hard coat layer 1 and the curable resin composition 3 for the second hard coat layer were adjusted to have a viscosity of 10 mPa·s. Then, the curable resin composition 1 for the first hard coat layer and the curable resin composition for the second hard coat layer are used from the TAC substrate side on the TAC substrate (TD80UL) which is conveyed at a speed of 20 m/min. The positional relationship of 3 is applied at the same time as the double layer. In this case, the wet film thickness of the coating film of the curable resin composition 1 for the first hard coat layer 1 and the curable resin composition 3 for the second hard coat layer is set to 25 μm and 5 μm, respectively.

Then, the coating film which was applied at the same time as the double layer was dried at 70 ° C for 60 seconds, and the ultraviolet ray was irradiated so as to have an integrated luminous flux of 120 mJ/cm ² in a nitrogen atmosphere to cure the coating film. Thus, a hard coat layer having a dry film thickness of 9 μm was formed to prepare an optical film.

(Example 6)

In the fifth embodiment, the wet film thickness of the coating film for the first hard coat layer curable resin composition 1 and the second hard coat layer curable resin composition 3 is set to 25 μm and 1 μm, respectively. An optical film was produced in the same manner as in Example 5 except that a hard coat layer having a dry film thickness of 8 μm was formed.

(Example 7)

In the fifth embodiment, the wet film thickness of the coating film for the first hard coat layer curable resin composition 1 and the second hard coat layer curable resin composition 3 was set to 18.75 μm and 3.75, respectively. An optical film was produced in the same manner as in Example 5 except that a hard coat layer having a dry film thickness of 5 μm was formed in μm.

(Comparative Example 7)

In the fifth embodiment, the curable resin composition 1 for the first hard coat layer was not used, and only the curable resin composition 3 for the second hard coat layer was applied by a wetting film thickness of 10 μm to form a dried film. An optical film was produced in the same manner as in Example 5 except that the hard coat layer was 5 μm thick.

(Example 8)

The curable resin composition 2 for the first hard coat layer 2 and the curable resin composition 4 for the second hard coat layer were each adjusted to have a viscosity of 30 mPa·s. Then, the curable resin composition 2 for the first hard coat layer and the curable resin composition for the second hard coat layer are used from the TAC substrate side on the TAC substrate (TD80UL) which is conveyed at a speed of 1 m/min. The positional relationship of 4 is applied in two layers at the same time. In this case, the wet film thickness of the coating film of the curable resin composition 2 for the first hard coat layer 2 and the curable resin composition 4 for the second hard coat layer is set to 20 μm and 10 μm, respectively.

Then, the coating film which was applied at the same time by double layer was dried at 25 ° C for 60 seconds, and the ultraviolet ray was irradiated so as to have an integrated luminous flux of 120 mJ/cm ² in a nitrogen atmosphere to cure the coating film. Thus, a hard coat layer having a dry film thickness of 14 μm was formed to prepare an optical film.

(Example 9)

An optical film was produced in the same manner as in Example 8 except that in Example 8, the drying temperature of the coating film simultaneously coated with both layers was changed to 50 °C.

(Embodiment 10)

An optical film was produced in the same manner as in Example 8 except that in Example 8, the drying temperature of the coating film simultaneously coated with the two layers was changed to 70 °C.

(Example 11)

An optical film was produced in the same manner as in Example 8 except that in Example 8, the drying temperature of the coating film simultaneously coated with both layers was changed to 100 °C.

(Embodiment 12)

In the tenth embodiment, the wet film thickness of the coating film for the first hard coat layer curable resin composition 2 and the second hard coat layer curable resin composition 4 is set to 25 μm and 5 μm, respectively. An optical film was produced in the same manner as in Example 10 except for the rest.

(Comparative Example 8)

In the tenth embodiment, the curable resin composition 4 for the second hard coat layer was not used, and only the curable resin composition 2 for the first hard coat layer was applied by a wetting film thickness of 20 μm to form a dried film. An optical film was produced in the same manner as in Example 10 except that the hard coat layer was 9 μm thick.

(Comparative Example 9)

In the tenth embodiment, the curable resin composition 2 for the first hard coat layer was not used, and only the curable resin composition 4 for the second hard coat layer was applied by a wetting film thickness of 10 μm to form a dried film. An optical film was produced in the same manner as in Example 10 except that the hard coat layer was 8 μm thick.

(Example 13)

In the first embodiment, the viscosity of the curable resin composition 1 for the first hard coat layer 1 and the curable resin composition 1 for the second hard coat layer was adjusted to 90 mPa ‧ s, respectively, and applied simultaneously. The wet film thickness of the coating film for the curable resin composition 1 for the first hard coat layer 1 and the curable resin composition 3 for the second hard coat layer is set to 25 μm and 5 μm, respectively, to form a dry film thickness. An optical film was produced in the same manner as in Example 1 except that a hard coat layer of 18 μm was used.

(Comparative Example 10)

In the first embodiment, the viscosity of the curable resin composition 1 for the first hard coat layer 1 and the curable resin composition 1 for the second hard coat layer were adjusted so as to be 4 mPa·s, respectively, to form a dry film. An optical film was produced in the same manner as in Example 1 except that the hard coat layer having a film thickness of 5 μm was used.

(Comparative Example 11)

In the first embodiment, the viscosity of the curable resin composition 1 for the first hard coat layer 1 and the curable resin composition 1 for the second hard coat layer were adjusted so as to be 10 mPa·s and 4 mPa·s, respectively. An optical film was produced in the same manner as in Example 1 except that a hard coat layer having a dry film thickness of 9 μm was formed.

(Comparative Example 12)

In the first embodiment, the viscosity of the curable resin composition 1 for the first hard coat layer 1 and the curable resin composition 1 for the second hard coat layer were adjusted so as to be 62 mPa ‧ s and 10 mPa ‧ s, respectively. An optical film was produced in the same manner as in Example 1 except that a hard coat layer having a dry film thickness of 17 μm was formed.

(Comparative Example 13)

In the first embodiment, the viscosity of the curable resin composition 1 for the first hard coat layer 1 and the curable resin composition 1 for the second hard coat layer are adjusted so as to be 10 mPa ‧ s, and the The adjusted two compositions were mixed in the same amounts as used in Example 1, and the mixed compositions were then coated on a TAC substrate. At this time, the coating film wetting film thickness of the mixed composition was set to 30 μm.

Then, the coating film was dried and irradiated with light in the same manner as in Example 1 to form a hard coat layer having a dry film thickness of 10 μm to obtain an optical film.

The composition types, wet film thickness, application method, dry film thickness and drying conditions, and transport speed of the TAC substrate used in the above examples and comparative examples are as shown in Table 1 below.

(Evaluation of optical film)

The optical films of the above-described examples and comparative examples were measured for reflectance, haze value (Hz), and total light transmittance as follows. Further, with respect to the optical films of the above-described examples and comparative examples, the interference pattern evaluation was performed as follows. The results are shown in Table 2.

Further, the cross-sectional photograph of the optical film of Example 1 is shown in Tables 3(a) and (b), and the cross-sectional photograph of the optical film of Comparative Example 3 is shown in Table 3(c). Further, in the photograph of the cross section of Table 3 (b), in the photograph of Table 3 (a), the HC layer was enlarged by the interface side of the opposite side of the TAC substrate.

(Measurement of reflectance)

The measurement of the reflectance was carried out by using a spectrophotometer model V7100, a UV-visible spectrophotometer manufactured by JASCO Corporation, and a product of VAR-7010 absolute reflectance, manufactured by JASCO Corporation. The incident angle was set to 5° and the polarizer was used. The N-polarized light was measured at a wavelength range of 380 to 780 nm, and a black tape was attached to the optical film on the side of the TAC substrate, and this was placed on a device and measured. Further, the average value of the measurement results obtained by the measurement wavelength range is regarded as the reflectance.

(Measurement of fog value and total light transmittance)

The fog value and total light transmittance are respectively reflected in accordance with JIS K-7136 and JIS K7361. The measurement was carried out by a transmittance meter HM-150 (manufactured by Murakami Color Technology Research Institute Co., Ltd.).

(evaluation of interference lines)

An interferometric inspection lamp (Na lamp) manufactured by FUNATECH Co., Ltd. was used for visual inspection, and evaluation was performed according to the following criteria.

○: almost no interference pattern was found

△: can see the interference pattern

╳: Obviously see the interference pattern

(evaluation of adhesion)

With respect to the optical films of the above examples and comparative examples, the adhesion ratio measurement of the checkerboard adhesion test shown below was carried out.

Further, in Comparative Example 12, since the surface was inferior, measurement was impossible.

(checkerboard adhesion test)

A 1 mm square and a total of 100 grids were placed on the side surface of the HC film on the side of the HC film, and 5 consecutive peeling tests were carried out using the ICGIBAN industrial 24mm celluloid tape (registered trademark), and calculated according to the following criteria. The proportion of squares remaining without peeling off.

Bonding rate (%) = (number of squares without peeling off / total number of squares 100) × 100

(evaluation of the surface)

The appearance of the optical film (with or without coating streaks) was evaluated by visual observation.

○: No coating spots were seen

△: Can blur the coating pattern

×: Obviously see the coated spot

(Results)

It is known from Table 2 that the examples are all low in reflectance and haze. The total light transmittance of the examples was a high value of 91.5% or more. Moreover, the examples have suppressed the occurrence of interference fringes. Further, the adhesion and the surface of the examples were both good. In particular, the surface shapes of Example 1 and Example 2 were relatively good.

It is known from Tables 3(a) and (b) of the optical film sectional view of Example 1, which is hollow. The cerium oxide microparticles are distributed from the opposite side (upper layer side) of the TAC substrate from the HC layer to the TAC substrate side, and the hollow cerium oxide microparticles are known from Table 3(b). Almost uniformly distributed from the interface of the HC layer on the opposite side of the TAC substrate to 5 μm.

Further, when Tables 3(a) to (c) were compared, the case of Example 1 was obtained, and the boundary between the hardened portion of the first composition and the hardened portion of the second composition was compared with the comparative example. Under 3, the former is less obvious.

However, Comparative Example 1 corresponding to the case where the second composition was not contained in Example 1 did not contain hollow ceria particles, and thus exhibited the same reflectance as that of the general hard coat layer.

In Comparative Example 2, which is equivalent to the case where the first composition is not present in the first embodiment, interference fringes occur and the adhesion ratio is also low. This phenomenon is presumed to be because the hollow ceria particles contained in the second composition are uniformly distributed in the HC layer and located at the interface of the HC layer on the side of the TAC substrate, thereby causing a gap between the TAC substrate and the hollow ceria particles. The difference in refractive index becomes large, causing the occurrence of interference fringes. Further, it is presumed that since the hollow ceria particles are located at the interface of the HC layer on the side of the TAC substrate, the resin of the HC layer penetrates into the TAC substrate and the area of the hardening is reduced, resulting in a decrease in adhesion.

Corresponding to Comparative Example 3 in which the simultaneous application was carried out without performing simultaneous coating in Example 1, the interference pattern was blurred. This phenomenon is presumed to be as clearly seen from the cross-sectional photograph of Table 3(c), in which the hardened portion of the first composition is clearly distinguished from the boundary of the hardened portion of the second composition, and the difference in refractive index of the boundary portion causes interference fringes to occur.

Corresponding to Comparative Example 4 in the case where there was no second composition in Example 2, as in Comparative Example 1, the reflectance was the same as that of the general hard coat layer.

Corresponding to Comparative Example 5 in the case where the first composition was not present in Example 2, as in Comparative Example 2, interference fringes occurred and the adhesion ratio was also low.

Corresponding to Comparative Example 6 in which the prebaking was carried out before drying in Example 2, the adhesion rate was low. This phenomenon is presumed to cause hardening of the first composition and the second composition (polymerization or crosslinking of the resin) due to the pre-baking operation, resulting in the first resin contained in the first composition on the side of the TAC substrate, which is not Fully penetrate into the TAC substrate.

Compared with Comparative Example 7 in the case where the first composition was not present in Example 5, as in Comparative Example 2, interference fringes occurred and the adhesion ratio was also low.

Comparative Example 8 corresponding to the case where there was no second composition in Example 10, as in Comparative Example 1, was only the same reflectance as the general hard coat layer.

Corresponding to Comparative Example 9 in the case where the first composition was not present in Example 10, as in Comparative Example 2, interference fringes occurred and the adhesion ratio was also low.

In Comparative Example 10, which corresponds to the case where the viscosity of the first composition and the second composition in Example 1 was small, the reflectance was lower than that of Comparative Example 1, but was higher than that of Example 1. This phenomenon is presumed to be due to the low viscosity of the two compositions, resulting in the mixing of the two components, resulting in the reduction of hollow ceria particles in the HC layer on the opposite side (upper side) of the TAC substrate, resulting in reflectance. improve.

In Comparative Example 11 in which the viscosity of the second composition on the upper layer side of the HC layer in Example 1 was small, the planar shape was not good.

In Comparative Example 12, which corresponds to a case where the difference in viscosity between the first composition and the second composition in Example 1 is large, a large number of plaques on the surface of the HC layer occur, resulting in a surface which is not smooth, which is impossible due to scattering of light. Determination of reflectance, haze value and total light transmittance.

Corresponding to Comparative Example 13 in which the first composition and the second composition were applied in a uniform mixture in Example 1, the reflectance was the same as that of Comparative Example 10. In addition, interference fringes occur and the adhesion rate is also low. This phenomenon is presumed to be applied because the two compositions are uniformly mixed, and as in Comparative Example 10, the presence of hollow ceria particles in the HC layer on the opposite side of the TAC substrate is reduced, resulting in an increase in reflectance. Further, as in Comparative Example 2, since the hollow ceria particles were located at the interface of the HC layer on the side of the TAC substrate, interference fringes occurred, and the adhesion rate was lowered.

[table 3]

1‧‧‧Optical film

2‧‧‧Polar plate

10‧‧‧Light penetrating substrate

20‧‧‧hard coating

30‧‧‧Low-refractive-index microparticles

40‧‧‧Mold

51, 52‧‧‧ slit

60‧‧‧First hardenable resin composition for hard coat

61‧‧‧ Coating of hard curable resin composition for the first hard coat layer

70‧‧‧The hard curable resin composition for the second hard coat layer

71‧‧‧Coating film of a hard curable resin composition for a second hard coat layer

80‧‧‧ Coating height

90‧‧‧ Total wet film thickness of the first and second compositions

100‧‧‧Study anti-reflection film

110‧‧‧Learly hard coating

120‧‧‧Low refractive index layer

130‧‧‧Transport direction of light penetrating substrate

140‧‧‧Antistatic layer

150‧‧‧Anti-fouling layer

160‧‧‧Protective film

170‧‧‧ polarizing layer

180‧‧‧ polarizer

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing an example of distribution of low refractive index fine particles in an HC layer of an optical film obtained by the production method of the present invention.

Fig. 2 is a schematic cross-sectional view showing an example of distribution of low refractive index fine particles in a low refractive index layer of an antireflection film obtained by a conventional double-layer coating method.

Fig. 3 is a view showing an example of a procedure for simultaneously applying a first and second HC layer curable resin composition in the method for producing an optical film of the present invention.

Fig. 4 is a view showing an example of a layer structure of a second optical film of the present invention.

Fig. 5 is a view showing another example of the layer structure of the second optical film of the present invention.

Fig. 6 is a view showing an example of a layer structure of a polarizing plate of the present invention.

1. . . Optical film

10. . . Light penetrating substrate

20. . . Hard coating

30. . . Low refractive index microparticles

Claims (9)

A method for producing an optical film, comprising: (i) a step of preparing a light-transmitting substrate; (ii) preparing a curable resin composition for the first hard coat layer and a hardenability for the second hard coat layer In the step of the resin composition, the first hard coat layer curable resin composition contains a reactive first resin and a first solvent, and does not contain low refractive index fine particles and a low refractive index resin, or even contains low refractive index The rate resin is also 5.0 mass% or less with respect to the mass of the first resin, and the viscosity μ1 is 3 mPa. s or more, the curable resin composition for the second hard coat layer contains one or more kinds of low refractive index components selected from the group consisting of low refractive index fine particles and low refractive index resins having an average particle diameter of 10 to 300 nm. And a reactive second resin and a second solvent, the viscosity μ2 is 5 mPa. s above, and the μ2 buckle minus the value of μ1 is at 30 mPa. (iii) at least one side of the light-transmitting substrate, from the side of the light-transmitting substrate, at least the hardening resin composition for the first hard coat layer and the second hard coat layer are hardened a resin composition adjacent to and performing simultaneous coating to form a coating film; and (iv) drying the coating film obtained according to the above step (iii), followed by performing light irradiation and/or heating to harden And the pre-baking is not performed between the (iii) step and the (iv) step. The method for producing an optical film according to claim 1, wherein in the step (iii), the first hard coat layer is coated with a curable resin composition. When the wet film thickness of the film is T1 and the wet film thickness of the coating film of the curable resin composition for the second hard coat layer is T2, T2/T1 is 0.01 to 1. The method for producing an optical film according to the second aspect of the invention, wherein, in the step (iii), the wet film thickness T1 of the coating film of the curable resin composition for the first hard coat layer is 18.75 to 25 μm. The wet film thickness T2 of the coating film of the curable resin composition for the second hard coat layer is 1 to 10 μm, and the film thickness of the hard coat layer after the step (iv) is 5 to 18 μm. The method for producing an optical film according to the first aspect of the invention, wherein the viscosity of the curable resin composition for the first hard coat layer is 1 to 95 mPa. s, the viscosity of the curable resin composition for the second hard coat layer is 2 to 100 mPa. s. An optical film obtained by the production method according to any one of claims 1 to 4. An optical film according to claim 5, wherein the optical film is provided with a hard coat layer on one side of the light-transmitting substrate, wherein low-refractive-index particles are present in the film thickness direction of the hard coat layer. The interface side of the opposite side of the light-transmitting substrate is more than the side of the light-transmitting substrate, and the amount of the low-refractive-index particles is smaller as the light-permeable substrate side is smaller. The opposite side of the light transmissive substrate faces the light transmissive substrate side, the low refractive index component gradually decreases; there is no layer interface in the hard coat layer; the hard coat layer has the above light penetration property In the checkerboard adhesion test of the substrate, the dense The connection rate is 90~100%. The optical film of claim 5, wherein the film thickness of the hard coat layer is 70 from the interface on the opposite side of the light-transmitting substrate to the dry film thickness of the hard coat layer. In the region up to %, 70 to 100% of the total amount of the low refractive index fine particles are present. A polarizing plate comprising a polarizing plate on a side opposite to the hard coat layer side of the optical film of the fifth aspect of the invention. A display is provided with a display panel in a light-transmitting substrate on the opposite side of the hard coat layer side of the optical film of the fifth aspect of the above patent application.