JP2010224150A - Method for manufacturing optical sheet, and optical sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical sheet which prevents the occurrence of interference fringes and has good appearance and is superior in productivity and allows function separation regardless of a plurality of hard coat layers, and an optical sheet. <P>SOLUTION: The method for manufacturing the optical sheet includes: a step of preparing a light-transmissive resin substrate; a step of preparing first and second curable resin compositions which contain a component having crosslinking reactivity and each of which has ≥30 mass% of a total solid content in all components; a step of simultaneously applying the first curable resin composition and the second curable resin composition to one surface side of the light-transmissive resin substrate in order from the side of the light-transmissive resin substrate to form coating films; and a step of hardening the coating films comprising the first and second curable resin compositions by light irradiation to the coating films to form a first hard coat layer and a second hard coat layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical sheet manufacturing method and an optical sheet used for the purpose of protecting the surface of a display or the like.

An image display surface in an image display device such as a liquid crystal display, a CRT display, a projection display, a plasma display, an electroluminescence display, or a reflection screen is required to be provided with scratch resistance so as not to be damaged when handled.
On the other hand, the scratch resistance of the image display surface of the image display device is improved by using a hard coat film or an optical sheet provided with a hard coat (hereinafter sometimes referred to as HC) layer on the base material. It is generally done.

  The HC layer in which only the binder component is cured often has insufficient scratch resistance and hardness, and a composition containing reactive inorganic fine particles in addition to the binder component is cured to form an HC layer. It is common to improve scratch resistance and hardness.

  In addition, two hard coat layers are generally laminated in order to improve hardness. The advantage of stacking two HC layers is that, in addition to improving the hardness by increasing the thickness, the content of reactive inorganic fine particles in the upper and lower layers is changed, and the content of reactive inorganic fine particles in the lower layer is compared to that in the upper layer. And increasing the lower layer to function as a base layer, and improving the property (also referred to as saponification resistance) of suppressing the dropping and outflow of silica fine particles from the surface when the optical sheet is alkali-treated.

  In Patent Literature 1, the first layer is semi-cured (also referred to as half cure) while suppressing the amount of light irradiation, and then the second layer composition is applied on the semi-cured first layer, The semi-cured first layer and the second layer coating are completely cured together (also referred to as full cure). In addition to the advantage that the layer interface is less likely to be generated by the method using half cure than the method of forming the first and second layers by full curing, the adhesion between the first and second layers is improved. There are advantages.

  However, in this method using half cure, since the coating and light irradiation steps are performed a plurality of times, there is a problem that the steps become complicated and the manufacturing cost increases.

  On the other hand, in patent document 2, the coating process is reduced by simultaneous multilayer coating, high productivity and adhesion between layers are obtained, and functional separation between layers is performed. However, in order to suppress the simultaneous mixing of a plurality of compositions applied at the time of curing, the first ionizing radiation is urgently applied, and after drying, a full-fledged second ionizing radiation is performed. The light irradiation process has not been reduced.

  In addition, when the first layer which is the hard coat layer or the antiglare layer of Patent Document 2 and the second layer which is the low refractive index layer are layers having functions different from each other, Functional separation can also be performed by simultaneous multi-layer coating (hereinafter also referred to as simultaneous multi-layer coating). However, when the components of the two layers are substantially the same, for example, when both layers are HC layers, 2 In some cases, the compositions were mixed with each other during the application of the two compositions. At this time, if the composition having different ratios of the reactive silica fine particles in the upper and lower layers is used as described above, the reactive silica fine particles are uniformly dispersed over the two layers by mixing. For example, the reactive silica in the lower layer When the proportion of the fine particles is larger than that of the upper layer, there is a problem that the effect of improving the hardness by the underlayer cannot be obtained and the saponification resistance is lowered, that is, the function separation is difficult. Furthermore, when the two compositions are mixed, uneven streaks (hereinafter also referred to as coating streaks) are generated, and there is a problem in that appearance defects are caused by the coating streaks.

  For these reasons, there is a demand for an optical sheet having a good appearance, no interference fringes, excellent productivity, and capable of separating functions even when a plurality of hard coat layers are laminated.

JP 2008-165041 A JP 2008-250267 A

  The present invention has been made to solve the above-described problems, has a good appearance, suppresses the generation of interference fringes, is excellent in productivity, and has functional separation even when a plurality of hard coat layers are laminated. An object of the present invention is to provide a method for producing an optical sheet and an optical sheet.

  As a result of intensive studies by the present inventors, in the simultaneous multi-layer coating having excellent productivity, the two compositions to be simultaneously coated form a composition for forming the same type of functional layer (for example, the two compositions are both hard coats). Even if it is a composition for forming a layer), it is possible to suppress mixing of the two compositions as a whole in simultaneous multi-layer coating by increasing the solid content concentration of all components of each composition to a certain level or more. However, in the part where the two compositions are in contact with each other, the two compositions are appropriately mixed so as not to generate an interface. Therefore, in the cured film of the composition, the coating streaks generated when the two compositions as a whole are mixed It was also found that the occurrence of interference fringes due to the presence of the layer interface was suppressed, and the two compositions were not mixed together, so that the function of each layer could be separated even when a plurality of functional layers of the same kind were laminated.

That is, the method for producing an optical sheet according to the present invention includes (i) a step of preparing a light-transmitting resin substrate,
(Ii) Reactive functional groups a, b, and c having cross-linking reactivity between the same type and different types of reactive functional groups, respectively, and having an average primary particle size 1 having a reactive functional group a on the particle surface The first reactive silica fine particle of ˜100 nm and the first binder component having the reactive functional group b are included, and the total solid content with respect to all the components of the first curable resin composition is 30% by mass or more. A first curable resin composition and a second binder component having a reactive functional group c, and the total solid content with respect to all components of the second curable resin composition is 30% by mass or more Preparing a second curable resin composition;
(Iii) The first curable resin composition and the second curable resin composition are simultaneously applied to one side of the light transmissive resin base material in this order from the light transmissive base material side, and the coating film The process of
(Iv) including light-irradiating the coating films of the first and second curable resin compositions, curing the coating films, and forming a first hard coat layer and a second hard coat layer. It is characterized by.

  In the first and second curable resin compositions, the total solid content is 30% by mass or more with respect to all the components, so that both the compositions for forming the hard coat layer can be used simultaneously. While suppressing the entire composition from being mixed when applied, the contact portions of the two compositions are appropriately mixed. And since it hardens | cures in a light irradiation process, maintaining the composition of each upper and lower layers in this way, generation | occurrence | production of a coating stripe can be suppressed and the external appearance of an optical sheet can be made favorable. In addition, since the contact portions of the two compositions are mixed appropriately, it is possible to separate functions such as hardness expression and flexibility expression of each layer, but no layer interface occurs, and interference fringes of the optical sheet are generated. It can be suppressed.

  In the present invention, the layer interface between the first hard coat layer and the second hard coat layer is visible in the observation using a TEM (transmission electron microscope) of the cross section in the film thickness direction of the optical sheet. It means a possible interface.

  The first reactive silica fine particles and the first binder component contained in the first curable resin composition and the second binder component contained in the second curable resin composition have reactive functional groups. A cross-linking reaction is possible between the same and different types of reactive functional groups, and a cross-linking bond is formed when cured by light irradiation, thereby contributing to an improvement in hardness.

According to the optical sheet manufacturing method of the present invention, the adhesion between the two layers of the first HC layer and the second HC layer is improved, and the hardness of the optical sheet is also improved.
The reason for this is not clear, but the following reason is presumed. In the case of the conventional method of half-curing and forming a laminate, only a small amount of the composition in the lower layer is irradiated with light once, but curing proceeds only with the components of the lower layer composition on the surface of the lower layer. Resulting in. On the other hand, since the production method according to the present invention does not perform half cure, the first reactive silica fine particles and the first binder of the composition on the coating film surface of the first curable resin composition as the lower layer. It is presumed that the second binder component of the second curable resin composition whose component is the upper layer can sufficiently react and the adhesion between the two layers and the hardness of the optical sheet are improved.

  In the method for producing an optical sheet according to the present invention, the first curable resin composition and the second curable resin composition each further contain a solvent, and all components of the first curable resin composition The total solid content is 40 to 60% by mass, and the total solid content is 40 to 60% by mass with respect to all components of the second curable resin composition. It is preferable from the viewpoint of suppressing mixing of the entire curable resin composition and suppressing generation of coating streaks.

The optical sheet according to the present invention is an optical sheet in which a first hard coat layer and a second hard coat layer are provided in this order on one surface side of a light transmissive resin base material from the light transmissive resin base material side. Because
The light-transmitting resin base material, the reactive functional groups a, b, and c having cross-linking reactivity between the same and different reactive functional groups, respectively, and having the reactive functional group a on the particle surface A first reactive silica fine particle having a primary particle size of 1 to 100 nm and a first binder component having a reactive functional group b, the total solid content of all the components of the first curable resin composition is 30 The first curable resin composition having a mass% or more and the second binder component having the reactive functional group c, and the total solid content with respect to all the components of the second curable resin composition is 30 mass. % Of the second curable resin composition is prepared,
The first curable resin composition and the second curable resin composition are simultaneously applied to one surface side of the light transmissive resin base material in order from the light transmissive resin base material side to form a coating film,
It is obtained by irradiating the coating film of the first and second curable resin compositions with light, curing the coating film, and forming the first hard coat layer and the second hard coat layer. There is no layer interface between the hard coat layer and the second hard coat layer.

  In the present invention, the layer interface between the first hard coat layer and the second hard coat layer is an interface that can be visually recognized in the observation using a TEM (transmission electron microscope) of the cross section in the film thickness direction of the optical sheet. Means.

  In a preferred embodiment of the optical sheet according to the present invention, the hardness of the pencil hardness test (4.9 N load) specified in JIS K5600-5-4 (1999) of the optical sheet can be 4H or more. .

In the definition of film and sheet in JIS-K6900, a sheet is a thin and generally flat product whose thickness is small relative to the length and width. A film has a thickness compared to the length and width. A thin, flat product that is extremely small and has an arbitrarily limited maximum thickness, usually supplied in the form of a roll. Accordingly, it can be said that a sheet having a particularly thin thickness among the sheets is a film, but the boundary between the sheet and the film is not clear and is difficult to clearly distinguish. Therefore, in the present invention, both the thick and thin sheets are used. Including meaning, it is defined as “sheet”.
In the present invention, the “hard coat layer” refers to a layer having a hardness of “H” or higher in a pencil hardness test (4.9 N load) defined in JIS K5600-5-4 (1999).

  In the method for producing an optical sheet according to the present invention, in each of the first and second curable resin compositions, the total solid content is 30% by mass or more with respect to all the components, thereby forming a hard coat layer together. Even if it is a composition for forming, the entire composition is prevented from mixing when applied at the same time, and cured in the light irradiation process while maintaining the composition of the upper and lower layers, so that the appearance of coating streaks is suppressed. It can be good. In addition, while suppressing mixing of the two curable resin compositions as a whole, the contact portions of the two curable resin compositions are mixed appropriately, so that no layer interface occurs, and generation of interference fringes on the optical sheet can be suppressed. . In addition, since full cure or half cure is not performed for each layer, the first reactive silica fine particles and the first binder component of the composition are present on the coating film surface of the first curable resin composition as the lower layer. The second binder component on the surface of the coating film of the second curable resin composition as the upper layer can sufficiently react, and the adhesion between the two layers is improved, and the hardness of the optical sheet is improved.

FIG. 1 is a diagram schematically illustrating an example of a layer configuration of an optical sheet according to the present invention. FIG. 2 is a diagram schematically illustrating another example of the layer configuration of the optical sheet according to the present invention. FIG. 3 is a diagram schematically showing an example of the simultaneous multilayer coating method. 4 is a TEM photograph of a cross section in the film thickness direction of the optical sheet of Example 4. FIG. 5 is a TEM photograph of a cross section in the film thickness direction of the optical sheet of Comparative Example 1. FIG. FIG. 6 is a photograph of the hard coat layer surface of the optical sheet of Comparative Example 1.

  Hereinafter, the optical sheet according to the present invention will be described first, and then the method for producing the optical sheet will be described.

In the present invention, (meth) acrylate represents acrylate and / or methacrylate.
In the present invention, the average primary particle size of the fine particles is a 50% particle size (d50 median size) when the fine particles in the solution are measured by a dynamic light scattering method and the particle size distribution is expressed as a cumulative distribution. means. The average primary particle size can be measured using a Microtrac particle size analyzer or a Nanotrac particle size analyzer manufactured by Nikkiso Co., Ltd.
The light of the present invention includes not only electromagnetic waves having wavelengths in the visible and non-visible regions, but also particle beams such as electron beams, and radiation or ionizing radiation that collectively refers to electromagnetic waves and particle beams.
In the present invention, unless otherwise specified, the film thickness means the film thickness during drying (dry film thickness).
In the present invention, the molecular weight means a weight average molecular weight which is a polystyrene equivalent value measured by gel permeation chromatography (GPC) when having a molecular weight distribution, and when having no molecular weight distribution, Mean molecular weight.
The spherical shape is a concept including not only a true sphere but also a shape that can approximate a sphere including a spheroid and a polyhedron.

(Optical sheet)
The optical sheet according to the present invention is an optical sheet in which a first hard coat layer and a second hard coat layer are provided in this order on one surface side of a light transmissive resin base material from the light transmissive resin base material side. Because
The light-transmitting resin base material, the reactive functional groups a, b, and c having cross-linking reactivity between the same and different reactive functional groups, respectively, and having the reactive functional group a on the particle surface A first reactive silica fine particle having a primary particle size of 1 to 100 nm and a first binder component having a reactive functional group b, the total solid content of all the components of the first curable resin composition is 30 The first curable resin composition having a mass% or more and the second binder component having the reactive functional group c, and the total solid content with respect to all the components of the second curable resin composition is 30 mass. % Of the second curable resin composition is prepared,
The first curable resin composition and the second curable resin composition are simultaneously applied to one surface side of the light transmissive resin base material in order from the light transmissive resin base material side to form a coating film,
It is obtained by irradiating the coating film of the first and second curable resin compositions with light, curing the coating film, and forming the first hard coat layer and the second hard coat layer. There is no layer interface between the hard coat layer and the second hard coat layer.

FIG. 1 is a diagram schematically illustrating an example of a layer configuration of an optical sheet according to the present invention.
In the optical sheet 1, the first hard coat layer 20 and the second hard coat layer 30 are provided in this order on one surface side of the light transmissive resin base material 10.

In the first and second curable resin compositions, the optical sheet according to the present invention forms a hard coat layer together by setting the total solid content to 30% by mass or more with respect to all components. Even if it is the composition of this, when apply | coating simultaneously, it can suppress that the whole composition mixes. As a result, the occurrence of coating streaks is suppressed and the appearance is improved, and the cured silica fine particles of the reactive silica fine particles contained in the first curable resin composition are not dispersed throughout the second hard coat layer. In addition, it exists mainly in the first hard coat layer and ensures the function of the first hard coat layer as an underlayer.
In addition, the optical sheet according to the present invention is moderately mixed at the contact portion of the two curable resin compositions, while mixing of the two curable resin compositions is suppressed, so that a layer interface occurs. Therefore, the occurrence of interference fringes on the optical sheet can be suppressed. Furthermore, since the optical sheet is not subjected to full cure for each layer and the upper and lower layers following the full cure and the lower half-cure, the surface of the first curable resin composition in the lower layer The first reactive silica fine particles and the first binder component of the composition are sufficiently reacted with the second reactive silica fine particles and the second binder component on the surface of the coating film of the second curable resin composition which is the upper layer. The adhesion between the two layers is improved and the hardness is excellent.

The layer interface between the first HC layer and the second HC layer means an interface that can be visually recognized in an observation using a TEM (transmission electron microscope) of a cross section in the film thickness direction of the optical sheet. Therefore, if the interface between the first HC layer and the second HC layer cannot be visually recognized by observation using a TEM, there is no layer interface.
The absence of the layer interface can also be confirmed by the absence of interference fringes. This is because there is no layer interface without interference fringes. The presence or absence of the interference fringes can be confirmed by attaching a black tape to the substrate side surface of the optical sheet and observing it under a three-wavelength tube lamp.

  Hereinafter, the light-transmitting resin base material essential for the optical sheet according to the present invention, the first hard coat layer, the second hard coat layer, and other layers that can be appropriately provided as necessary will be described in order. .

(Light transmissive resin substrate)
The light-transmitting resin substrate used in the present invention is a plastic film or sheet having a high light-transmitting property, and is particularly limited as long as it satisfies physical properties that can be used as the light-transmitting resin substrate of the optical sheet. And can be selected and used as appropriate.
Usually, the substrate used for the optical sheet may be transparent, translucent, colorless, or colored, but is required to have light transmittance. In addition, the measurement of light transmittance uses the value measured in room temperature and air | atmosphere using the ultraviolet visible spectrophotometer (For example, Shimadzu Corporation UV-3100PC). The average light transmittance of the light transmissive resin substrate is preferably 70% or more, and more preferably 85% or more.

  In the present invention, the thickness of the light-transmitting resin base material can be appropriately selected and used. However, the light-transmitting resin having a thickness of 10 to 200 μm is preferable because the surface of the optical sheet is hard to break and imparts hardness. A base material is preferably used, and more preferably 30 to 150 μm.

  Preferable materials for the light-transmitting resin base material include cellulose acylate, cycloolefin polymer, polycarbonate, acrylate polymer, or polyester. Here, “mainly” means a component having the highest content ratio among the constituent components of the base material.

Specific examples of cellulose acylate include cellulose triacetate, cellulose diacetate, and cellulose acetate butyrate.
Examples of the cycloolefin polymer include a norbornene polymer, a monocyclic olefin polymer, a cyclic conjugated diene polymer, a vinyl alicyclic hydrocarbon polymer resin, and more specifically, ZEONEX and ZEONOR (norbornene resin) manufactured by Nippon Zeon Co., Ltd., Sumilite FS-1700 manufactured by Sumitomo Bakelite Co., Ltd., Arton (modified norbornene resin) manufactured by JSR Co., Ltd. Copolymer), Topas (cyclic olefin copolymer) manufactured by Ticona, Optretz OZ-1000 series (alicyclic acrylic resin) manufactured by Hitachi Chemical Co., Ltd., and the like.
Specific examples of the polycarbonate include aromatic polycarbonates based on bisphenols (such as bisphenol A) and aliphatic polycarbonates such as diethylene glycol bisallyl carbonate.
Specific examples of the acrylate polymer include methyl poly (meth) acrylate, poly (meth) ethyl acrylate, methyl (meth) acrylate-butyl (meth) acrylate, and the like.
Specific examples of the polyester include polyethylene terephthalate and polyethylene naphthalate.

As the light-transmitting resin base material used in the present invention, the material having the highest light transmittance is cellulose acylate, and it is preferable to use triacetyl cellulose.
A triacetyl cellulose (hereinafter sometimes referred to as TAC) film is a light-transmitting resin base material capable of having an average light transmittance of 50% or more in a visible light region of 380 to 780 nm.
Since the TAC film has optical isotropy, it can be preferably used in the case of a liquid crystal display application.

  In addition, as triacetyl cellulose in the present invention, in addition to pure triacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, and the like are used in combination with components other than acetic acid as fatty acids forming esters with cellulose. Also good. Further, these triacetyl celluloses may be added with other additives such as other cellulose lower fatty acid esters such as diacetyl cellulose, or plasticizers, antistatic agents, ultraviolet absorbers and the like, if necessary.

  In the present invention, the TAC film may be subjected to surface treatment (eg, saponification treatment, glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, flame treatment), and a primer layer (adhesive layer). It may be formed. The light-transmitting resin substrate in the present invention refers to those including these surface treatments and primer layers.

(First hard coat layer)
The first hard coat layer of the present invention comprises a first reactive silica fine particle having an average primary particle diameter of 1 to 100 nm having a reactive functional group a on the particle surface, and a first binder having a reactive functional group b. It consists of the hardened | cured material of the 1st curable resin composition containing the component and the sum total of the solid content with respect to all the components of a 1st curable resin composition is 30 mass% or more.

  The first HC layer is a layer provided between the light-transmitting resin base material and a second HC layer described later, and is formed simultaneously with the second HC layer by light irradiation.

  Since the first reactive silica fine particles and the first binder component each have a reactive functional group capable of crosslinking reaction between the same kind and different kinds of reactive functional groups, including the second binder component described later, In addition to increasing the crosslink density during curing and contributing to the hardness improvement of the first HC layer, the second binder component also undergoes a crosslinking reaction at the boundary with the second HC layer that is applied and cured at the same time. This also contributes to improving the adhesion between the HC layer and the second HC layer.

  Since the first HC layer and the second HC layer are formed at the same time, it has excellent adhesion and can suppress the occurrence of interference fringes while achieving functional separation between the first HC layer and the second HC layer. it can.

  The film thickness of the first HC layer is not particularly limited and may be appropriately adjusted according to the required performance of the optical sheet, and is preferably 5 to 20 μm. Further, the total thickness of the first HC layer and the second HC layer is preferably 10 to 40 μm. When the sum is 10 μm or more, the effect of the present invention due to the improvement in hardness is easily exhibited. When the sum is thicker than 40 μm, the curl of the optical sheet becomes tight and cracks are likely to occur. In addition, the cost increases.

  Hereinafter, the 1st curable resin composition which hardens | cures and becomes the 1st HC layer of this invention is demonstrated.

(First curable resin composition)
The first curable resin composition of the present invention comprises a reactive silica fine particle having an average primary particle diameter of 1 to 100 nm having a reactive functional group a on the surface of the silica fine particle, and a first binder having a reactive functional group b. Contains ingredients.

  In the first curable resin composition, the total solid content is 30% by mass or more based on the total components. The solid content of the first curable resin composition includes at least the first reactive silica fine particles and the first binder component. The total of the solid content is 40 from the point of improving the applicability, and from the point of suppressing the overall mixing of the first and second curable resin composition and suppressing the occurrence of coating streaks and maintaining a good appearance. -60 mass% is more preferable. If it is less than 30% by mass, the second curable resin composition to be described later and the entire composition are mixed, and the hardness and flexibility of the first HC layer and the second HC layer, and the function by the additive for each layer. The functional separation such as the expression of the ink cannot be performed, the coating streaks are generated, and the appearance is deteriorated.

  From the point of controlling the mixing of the first and second curable resin compositions, the viscosity of the first curable resin composition is 5 to 50 mPa · s, and the viscosity of the second curable resin composition is 3 It is preferable that the viscosity of the first curable resin composition is equal to or higher than that of the second curable resin composition.

  If the total solid content is 30% by mass or more with respect to all components of the first curable resin composition, antiglare agent, antifouling agent, antistatic agent, coating suitability for the purpose of imparting functionality. For the purpose of control, a leveling agent, a solvent, and a lubricant may be contained for the purpose of preventing blocking.

(First reactive silica fine particles)
The first reactive silica fine particle has a reactive functional group b of the first binder component and a reactive functional group c of the second binder component described later on the surface of the silica fine particles having an average primary particle size of 1 to 100 nm. When the first curable resin composition is cured to form the first HC layer by having a reactive functional group a having a crosslinking reactivity with, a crosslinking reaction with these crosslinkable components, This contributes to improving the adhesion between the first HC layer and the second HC layer and the hardness of the optical sheet.

  The average primary particle size of the first reactive silica fine particles is 1 to 100 nm, preferably 10 to 80 nm, and more preferably 12 to 50 nm. If the average primary particle size of the reactive silica fine particles is less than 1 nm, it cannot contribute to the improvement of the hardness of the hard coat layer. When the average primary particle size exceeds 100 nm, haze increases.

  The first reactive silica fine particles have a particle size distribution from the viewpoint of improving the hardness while maintaining the restoration rate when only the first binder component described later is used without impairing the light transmittance. More preferably it is narrow and monodisperse.

  The surface of the silica fine particles usually has groups that cannot exist in this form in the silica fine particles. These surface groups are usually functional groups that are relatively reactive. For example, in the case of metal oxides, for example, hydroxyl groups and oxy groups, for example in the case of metal sulfides, thiol groups and thio groups, or in the case of nitrides, for example, amino groups, amide groups and imides. Has a group.

  The ratio of the content of the first reactive silica fine particles relative to the total solid content of the first curable resin composition may be appropriately adjusted according to the required physical properties of the optical sheet. It is preferably contained in an amount of 35% by mass, more preferably 35 to 65% by mass, and still more preferably 50 to 65% by mass. If it is less than 15% by mass, there is a possibility that sufficient hardness cannot be imparted to the hard coat layer. When the fine particles are closely packed, the content of the fine particles with respect to the curable resin composition is 70% by mass. When the content exceeds 70% by mass, the filling rate is excessively increased and the adhesion between the silica fine particles and the first binder component is increased. There is a risk that the hardness of the first HC layer will be lowered.

  The first reactive silica fine particles may be used not only having a single average primary particle size but also a combination of two or more types having different average primary particle sizes. When two or more types are used in combination, the average primary particle size of each particle may be within 1 to 100 nm.

  From the viewpoint of improving the hardness of the first HC layer, the first reactive silica fine particles of the present invention are preferably solid particles having no pores or porous structure inside the first HC layer. From the viewpoint of lowering the refractive index, it is preferable to use particles having pores or a porous structure inside the particles such as hollow particles.

  The first reactive silica fine particles may be those that further impart functions to the first HC layer, and are appropriately selected and used according to the purpose.

The reactive functional group a which the first reactive silica fine particles have on the surface is appropriately selected according to the first binder component and the second binder component. As the reactive functional group a, a polymerizable unsaturated group is suitably used, preferably a photocurable unsaturated group, and particularly preferably an ionizing radiation curable unsaturated group. Specific examples thereof include ethylenically unsaturated bonds such as (meth) acryloyl group, vinyl group and allyl group, and epoxy group.
The reactive functional group a of the first reactive silica fine particles, the reactive functional group b of the first binder component, and the reactive functional group c of the second binder component may be the same or different.

  The first reactive silica fine particles have at least a part of the surface coated with an organic component, and have a reactive functional group a introduced by the organic component on the surface. Here, the organic component is a component containing carbon. Moreover, as an aspect in which at least a part of the surface is coated with an organic component, for example, a compound containing an organic component such as a silane coupling agent reacts with a hydroxyl group present on the surface of the silica fine particles to cause a part of the surface In addition to the mode in which the organic component is bonded to the surface, or the mode in which the compound containing the organic component having an isocyanate group reacts with the hydroxyl group present on the surface of the silica fine particles, the organic component is bonded to a part of the surface. Examples include an aspect in which an organic component is attached to a hydroxyl group present on the surface of the silica fine particle by an interaction such as hydrogen bonding, and an aspect in which one or two or more silica fine particles are contained in the polymer particle.

As a method for preparing reactive silica fine particles having a reactive functional group a introduced on the surface thereof, the organic component being coated on at least a part of the surface, the reactive functional group a to be introduced into the silica fine particles Thus, a conventionally known method can be appropriately selected and used.
Among them, in the present invention, it is preferable to select and use any one of the following silica fine particles (i) and (ii) from the viewpoint of suppressing aggregation of the silica fine particles and improving the hardness of the film.
(I) saturated or unsaturated carboxylic acid, acid anhydride, acid chloride, ester and acid amide corresponding to the carboxylic acid, amino acid, imine, nitrile, isonitrile, epoxy compound, amine, β-dicarbonyl compound, silane, And by dispersing silica fine particles in water and / or an organic solvent as a dispersion medium in the presence of one or more surface modification compounds having a molecular weight of 500 or less selected from the group consisting of metal compounds having functional groups. Silica fine particles having a reactive functional group a on the surface.
(Ii) a compound containing a reactive functional group a introduced into silica fine particles before coating, a group represented by the following chemical formula (1), and a silanol group or a group that generates a silanol group by hydrolysis, and metal oxide fine particles Silica fine particles having a reactive functional group a on the surface, obtained by bonding.
Chemical formula (1)
−Q ¹ −C (= Q ² ) −Q ³ −
In chemical formula (1), Q ¹ represents NH, O (oxygen atom), or S (sulfur atom), Q ² represents O or S, and Q ³ represents NH or a divalent or higher valent organic group. .

Hereinafter, the 1st reactive silica fine particle used suitably is demonstrated in order.
(I) saturated or unsaturated carboxylic acid, acid anhydride, acid chloride, ester and acid amide corresponding to the carboxylic acid, amino acid, imine, nitrile, isonitrile, epoxy compound, amine, β-dicarbonyl compound, silane, And by dispersing silica fine particles in water and / or an organic solvent as a dispersion medium in the presence of one or more surface modification compounds having a molecular weight of 500 or less selected from the group consisting of metal compounds having functional groups. Silica fine particles having a reactive functional group a on the surface.
When the reactive silica fine particles (i) are used, there is an advantage that the film strength can be improved even if the organic component content is small.

  The surface modifying compound used in the reactive silica fine particles (i) is a carboxyl group, an acid anhydride group, an acid chloride group, an acid amide group, an ester group, an imino group, a nitrile group, an isonitrile group, a hydroxyl group, or a thiol. Groups, epoxy groups, primary, secondary and tertiary amino groups, Si-OH groups, hydrolysable residues of silanes, or CH acid groups such as β-dicarbonyl compounds It has a functional group capable of chemically bonding with a group present on the surface of the silica fine particle under conditions. The chemical bond here preferably includes a covalent bond, an ionic bond or a coordinate bond, but also includes a hydrogen bond. The coordination bond is considered to be complex formation. For example, acidic / base reaction, complex formation or esterification according to Bronsted or Lewis occurs between the functional group of the surface modifying compound and the group on the surface of the silica fine particle. The said surface modification compound used for the reactive silica fine particle of said (i) can be used 1 type or in mixture of 2 or more types.

The surface modifying compound is usually added to the surface modifying compound via the functional group in addition to at least one functional group (hereinafter referred to as the first functional group) that can participate in chemical bonding with the surface group of the silica fine particles. After binding, it has molecular residues that impart new properties to the silica particles. The molecular residue or a part thereof is hydrophobic or hydrophilic and, for example, stabilizes, integrates or activates silica fine particles.
For example, examples of the hydrophobic molecular residue include an alkyl, aryl, alkaryl, aralkyl, or fluorine-containing alkyl group that causes inactivation or repulsion. Examples of the hydrophilic group include a hydroxy group, an alkoxy group, and a polyester group.

  When a reactive functional group a capable of reacting with other reactive functional groups b to d is contained in the molecular residue of the surface modifying compound, the first functional group contained in the surface modifying compound is By reacting on the surface of the silica fine particles, it is possible to introduce the reactive functional group a capable of reacting with the binder component on the surface of the reactive silica fine particles (i). For example, in addition to the first functional group, a surface modification compound further having a polymerizable unsaturated group is preferable.

  On the other hand, a second functional group is contained in the molecular residue of the surface modification compound, and another reaction is performed on the surface of the reactive silica fine particle (i) using the second functional group as a foothold. A reactive functional group a capable of reacting with the functional functional groups b to d may be introduced. For example, a group (hydrogen bond forming group) capable of hydrogen bonding such as a hydroxyl group and an oxy group is introduced as the second functional group, and another surface modification is added to the hydrogen bond forming group introduced on the surface of the fine particles. It is preferable to introduce a reactive functional group a capable of reacting with other reactive functional groups b to d by the reaction of the hydrogen bond forming group of the compound. That is, as the surface modification compound, it is preferable to use a compound having a hydrogen bond-forming group and a compound having a reactive functional group a capable of reacting with a binder component such as a polymerizable unsaturated group and a compound having a hydrogen bond-forming group in combination. An example. Specific examples of the hydrogen bond-forming group indicate a functional group such as a hydroxyl group, a carboxyl group, an epoxy group, a glycidyl group, an amide group, or an amide bond. Here, the amide bond indicates that the bond unit contains —NHC (O) or> NC (O) —. Among the hydrogen bond forming groups used in the surface modification compound of the present invention, among them, a carboxyl group, a hydroxyl group, and an amide group are preferable.

  The surface-modifying compound used in the reactive silica fine particles (i) has a molecular weight of 500 or less, more preferably 400, particularly 200. Since it has such a low molecular weight, it is presumed that the surface of the silica fine particles can be rapidly occupied and aggregation of the silica fine particles can be prevented.

  The surface modifying compound used in the reactive silica fine particles (i) is preferably a liquid under the reaction conditions for surface modification, and is preferably soluble or at least emulsifiable in a dispersion medium. Among these, it is preferable that the polymer is dissolved in the dispersion medium and uniformly distributed as discrete molecules or molecular ions in the dispersion medium.

  Saturated or unsaturated carboxylic acids have 1 to 24 carbon atoms, such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, acrylic acid, methacrylic acid, crotonic acid, citric acid, Examples include adipic acid, succinic acid, glutaric acid, oxalic acid, maleic acid, fumaric acid, itaconic acid and stearic acid, and the corresponding acid anhydrides, chlorides, esters and amides such as caprolactam. Further, when an unsaturated carboxylic acid is used, a polymerizable unsaturated group can be introduced.

Examples of preferred amines are those having the chemical formula Q _3-n NH _n (n = 0, 1 or 2), wherein the residue Q is independently 1-12, in particular 1-6, particularly preferably 1- Alkyl having 4 carbon atoms (eg, methyl, ethyl, n-propyl, i-propyl and butyl) and aryl, alkaryl or aralkyl having 6-24 carbon atoms (eg, phenyl, naphthyl, tolyl and benzyl) Represents. Examples of preferred amines include polyalkyleneamines, and specific examples are methylamine, dimethylamine, trimethylamine, ethylamine, aniline, N-methylaniline, diphenylamine, triphenylamine, toluidine, ethylenediamine, and diethylenetriamine. .

Preferred β-dicarbonyl compounds are those having 4 to 12, particularly 5 to 8 carbon atoms, such as diketones (such as acetylacetone), 2,3-hexanedione, 3,5-heptanedione, acetoacetic acid, acetoacetate. Examples include acetic acid-C ₁ -C ₄ -alkyl esters (such as acetoacetic acid ethyl ester), diacetyl and acetonylacetone.
Examples of amino acids include β-alanine, glycine, valine, aminocaproic acid, leucine and isoleucine.

  Preferred silanes are hydrolyzable organosilanes having at least one hydrolyzable group or hydroxy group and at least one non-hydrolyzable residue. Here, examples of the hydrolyzable group include a halogen, an alkoxy group, and an acyloxy group. As the non-hydrolyzable residue, a non-hydrolyzable residue having a reactive functional group a and / or not having a reactive functional group a is used. Silanes having at least partially organic residues substituted with fluorine may also be used.

As the silane used is not particularly limited, for _{example, CH 2 = CHSi (OOCCH 3} ) 3, CH 2 = CHSiCl 3, CH 2 = CHSi (OC 2 H 5) 3, CH 2 = CHSi (OC 2 H _{4 OCH 3) 3, CH 2} = CH-CH 2 -Si (OC 2 H 5) 3, CH 2 = CH-CH 2 -Si (OOCCH 3) 3, γ- glycidyloxypropyltrimethoxysilane (GPTS), γ-glycidyloxypropyldimethylchlorosilane, 3-aminopropyltrimethoxysilane (APTS), 3-aminopropyltriethoxysilane (APTES), N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- [ N '-(2'-aminoethyl) -2-aminoethyl] -3-aminopropyltrimethoxy Sisilane, hydroxymethyltrimethoxysilane, 2- [methoxy (polyethyleneoxy) propyl] trimethoxysilane, bis- (hydroxyethyl) -3-aminopropyltriethoxysilane, N-hydroxyethyl-N-methylaminopropyltriethoxysilane , 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, and the like.

  The silane coupling agent is not particularly limited, and may include known ones. For example, KBM-502, KBM-503, KBE-502, KBE-503, KBM-5103 (trade names, both And Shin-Etsu Chemical Co., Ltd.).

As a metal compound which has a functional group, the metal compound of the metal M from 1st group III-V and / or 2nd group II-IV of an element periodic table is mentioned. Zirconium and titanium alkoxides, M (OR) ₄ (M = Ti, Zr), wherein part of the OR group is replaced by a complexing agent such as a β-dicarbonyl compound or a monocarboxylic acid. Can be mentioned. When a compound having a polymerizable unsaturated group (such as methacrylic acid) is used as a complexing agent, a polymerizable unsaturated group can be introduced.

As the dispersion medium, water and / or an organic solvent is preferably used. A particularly preferred dispersion medium is distilled (pure) water. As the organic solvent, polar, nonpolar and aprotic solvents are preferred. Examples thereof include alcohols such as aliphatic alcohols having 1 to 6 carbon atoms (especially methanol, ethanol, n (normal)-and i (iso) -propanol and butanol), methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, acetone and Ketones such as butanone, esters such as ethyl acetate; ethers such as diethyl ether, tetrahydrofuran and tetrahydropyran; amides such as dimethylacetamide and dimethylformamide; sulfoxides and sulfones such as sulfolane and dimethyl sulfoxide; and pentane; Aliphatic (optionally halogenated) hydrocarbons such as hexane and cyclohexane. These dispersion media can be used as a mixture.
The dispersion medium preferably has a boiling point that can be easily removed by distillation (optionally under reduced pressure), and a solvent having a boiling point of 200 ° C. or lower, particularly 150 ° C. or lower is preferable.

  In preparing the reactive silica fine particles (i), the concentration of the dispersion medium is usually 40 to 90, preferably 50 to 80, particularly 55 to 75% by mass. The remainder of the dispersion is composed of untreated silica fine particles and the surface modifying compound. Here, the mass ratio of silica fine particles / surface modification compound is preferably 100: 1 to 4: 1, more preferably 50: 1 to 8: 1, and further preferably 25: 1 to 10: 1. .

  The preparation of the reactive silica fine particles (i) is preferably performed at room temperature (about 20 ° C.) to the boiling point of the dispersion medium. Particularly preferably, the dispersion temperature is 50 to 100 ° C. The dispersion time depends in particular on the type of material used, but is generally a few minutes to a few hours, for example 1 to 24 hours.

(Ii) a reactive functional group a introduced into the silica fine particles before coating, a compound represented by the following chemical formula (1), a compound containing a silanol group or a group that generates a silanol group by hydrolysis, and silica fine particles as a core Silica fine particles having a reactive functional group a on the surface, obtained by bonding the metal oxide fine particles.
Chemical formula (1)
−Q ¹ −C (= Q ² ) −Q ³ −
In chemical formula (1), Q ¹ represents NH, O (oxygen atom), or S (sulfur atom), Q ² represents O or S, and Q ³ represents NH or a divalent or higher valent organic group. .
When the reactive silica fine particles (ii) are used, there are advantages that the amount of the organic component is increased, and the dispersibility and the film strength are further increased.

First, a compound containing a reactive functional group a to be introduced into silica fine particles before coating, a group represented by the above chemical formula (1), and a silanol group or a group that generates a silanol group by hydrolysis (hereinafter referred to as reactive functional group-modified hydrolysis). The case may be referred to as decomposable silane).
In the reactive functional group-modified hydrolyzable silane, the reactive functional group a desired to be introduced into the silica fine particles is not particularly limited as long as it is appropriately selected so that it can react with the other reactive functional groups b to d. Suitable for introducing polymerizable unsaturated groups as described above.

In the reactive functional group-modified hydrolyzable silane, the [—Q ¹ —C (═Q ² ) —] moiety of the group represented by the chemical formula (1) is specifically [—O—C (═O )-], [-OC (= S)-], [-SC (= O)-], [-NH-C (= O)-], [-NH-C (= S)- ] And [-S-C (= S)-]. These groups can be used individually by 1 type or in combination of 2 or more types. Among them, from the viewpoint of thermal stability, at least of a [—O—C (═O) —] group, a [—O—C (═S) —] group, and a [—S—C (═O) —] group. It is preferable to use one type in combination. The group [—Q ¹ —C (= Q ² ) —Q ³ —] represented by the chemical formula (1) generates an appropriate cohesive force due to hydrogen bonding between molecules, and has excellent mechanical properties when formed into a cured product. It is considered that properties such as strength, adhesion to a substrate and heat resistance can be imparted.

  Examples of the group that generates a silanol group by hydrolysis include groups having an alkoxy group, an aryloxy group, an acetoxy group, an amino group, a halogen atom, etc. on the silicon atom. An oxysilyl group is preferred. A silanol group or a group that forms a silanol group by hydrolysis can be combined with the metal oxide fine particles by a condensation reaction or a condensation reaction that occurs following hydrolysis.

  Specific examples of the reactive functional group-modified hydrolyzable silane include compounds represented by the following chemical formulas (2) and (3). The compound represented by the chemical formula (3) is more preferable in terms of hardness. Preferably used.

In the chemical formulas (2) and (3), R ^a and R ^b may be the same or different, and are a hydrogen atom or a C ₁ to C ₈ alkyl group or aryl group, for example, methyl, ethyl, propyl, Examples thereof include butyl, octyl, phenyl and xylyl groups. Here, m is 1, 2 or 3.
Examples of the group represented by [(R ^a O) _m R ^b _3-m Si—] include a trimethoxysilyl group, a triethoxysilyl group, a triphenoxysilyl group, a methyldimethoxysilyl group, and a dimethylmethoxysilyl group. Can be mentioned. Of these groups, a trimethoxysilyl group or a triethoxysilyl group is preferable.

In the chemical formulas (2) and (3), R ^c is a divalent organic group having a C ₁ to C ₁₂ aliphatic or aromatic structure, and may contain a chain, branched or cyclic structure. . Examples of such an organic group include methylene, ethylene, propylene, butylene, hexamethylene, cyclohexylene, phenylene, xylylene, and dodecamethylene. Among these, preferred examples are methylene, propylene, cyclohexylene, phenylene and the like.

In the chemical formula (2), R ^d is a divalent organic group and is usually selected from divalent organic groups having a molecular weight of 14 to 10,000, preferably a molecular weight of 76 to 500. For example, chain polyalkylene groups such as hexamethylene, octamethylene, dodecamethylene; alicyclic or polycyclic divalent organic groups such as cyclohexylene and norbornylene; divalent groups such as phenylene, naphthylene, biphenylene and polyphenylene Aromatic group; and these alkyl group-substituted and aryl group-substituted products. In addition, these divalent organic groups may contain an atomic group containing an element other than carbon and hydrogen atoms, and include a polyether bond, a polyester bond, a polyamide bond, a polycarbonate bond, and a group represented by the chemical formula (1). Can also be included.

In the chemical formulas (2) and (3), R ^e is an (n + 1) -valent organic group, and is preferably selected from a chain, branched or cyclic saturated hydrocarbon group and unsaturated hydrocarbon group.

  In the chemical formulas (2) and (3), Y ′ represents a monovalent organic group having a reactive functional group a. The reactive functional group a itself as described above may be used. For example, when the reactive functional group a is selected from a polymerizable unsaturated group, a (meth) acryloyl (oxy) group, a vinyl (oxy) group, a propenyl (oxy) group, a butadienyl (oxy) group, a styryl (oxy) group Ethynyl (oxy) group, cinnamoyl (oxy) group, maleate group, (meth) acrylamide group and the like. N is preferably a positive integer of 1 to 20, more preferably 1 to 10, particularly preferably 1 to 5.

  For the synthesis of the reactive functional group-modified hydrolyzable silane used in the present invention, for example, a method described in JP-A-9-100111 can be used. That is, for example, when it is desired to introduce a polymerizable unsaturated group, (i) it is carried out by an addition reaction of a mercaptoalkoxysilane, a polyisocyanate compound, and an active hydrogen group-containing polymerizable unsaturated compound capable of reacting with an isocyanate group. it can. Further, (b) the reaction can be carried out by a direct reaction between a compound having an alkoxysilyl group and an isocyanate group in the molecule and an active hydrogen group-containing polymerizable unsaturated compound. Furthermore, (c) it can also be directly synthesized by an addition reaction of a compound having a polymerizable unsaturated group and an isocyanate group in the molecule with mercaptoalkoxysilane or aminosilane.

  In the production of the reactive silica fine particles of (ii), a method in which a reactive functional group-modified hydrolyzable silane is separately hydrolyzed and then mixed with silica fine particles, followed by heating and stirring, or a reaction A method for hydrolyzing a functional functional group-modified hydrolyzable silane in the presence of silica fine particles, and in the presence of other components such as polyunsaturated organic compounds, monounsaturated organic compounds, radiation polymerization initiators, etc. A method of performing surface treatment of silica fine particles can be selected, but a method of hydrolyzing a reactive functional group-modified hydrolyzable silane in the presence of silica fine particles is preferable. When the reactive silica fine particles (ii) are produced, the temperature is usually 20 ° C. or higher and 150 ° C. or lower, and the treatment time is in the range of 5 minutes to 24 hours.

  In order to accelerate the hydrolysis reaction, an acid, salt or base may be added as a catalyst. Suitable acids include organic acids and unsaturated organic acids; examples of bases include tertiary amines or quaternary ammonium hydroxides. The amount of the acid or base catalyst added is 0.001 to 1.0% by mass, preferably 0.01 to 0.1% by mass, based on the reactive functional group-modified hydrolyzable silane.

  As the first reactive silica fine particles, powdery fine particles that do not contain a dispersion medium may be used, but a dispersion step can be omitted, and from the viewpoint of high productivity, a fine particle made of a solvent dispersion sol should be used. preferable.

  Commercially available products of the first reactive silica fine particles include MIBK-SD, MIBK-SDMS, MIBK-SDL, MIBK-SDZL manufactured by Nissan Chemical Industries, Ltd., DP1021, DP1022 manufactured by JGC Catalysts & Chemicals, Inc. DP1032, DP1037, DP1041, DP1042, DP1044, etc. can be mentioned.

  In the present invention, the first reactive silica fine particles have a reactive functional group a having 3 to 20 spherical silica fine particles having an average primary particle diameter of 1 to 100 nm bonded by an inorganic chemical bond. The deformed silica fine particles are preferable because the hardness of the HC layer can be further improved.

Hereinafter, the reactive irregularly shaped silica fine particles will be described.
Reactive deformed silica fine particles are formed by combining 3 to 20 spherical silica fine particles having an average primary particle diameter of 1 to 100 nm by an inorganic chemical bond to form deformed silica fine particles. It has the group a.

  When the reactive irregularly shaped silica fine particles are viewed as aggregated particles, the aggregated reactive silica fine particles having a particle size comparable to that of the reactive irregularly shaped silica fine particles have higher strength as the aggregated particles. Also excellent in hardness.

  The size of the reactive deformed silica fine particles in which 3 to 20 spherical silica fine particles having an average primary particle diameter of 1 to 100 nm are bonded by an inorganic chemical bond, that is, the length of the major axis may be appropriately adjusted. It is preferable that it is 20-300 nm. If it is this range, it will be easy to give hardness to HC layer, and it will be easy to maintain the light transmittance of HC layer.

  The spherical shape is a concept including not only a true sphere but also a shape that can approximate a sphere including a spheroid and a polyhedron.

  The size of the reactive irregularly shaped silica fine particles can be measured in the first curable resin composition by the same method as that of the reactive silica fine particles. In the first HC layer, the cross section of the hard coat layer is measured. The number of hardened deformed silica fine particles observed using SEM or TEM photographs was counted 100, the average value of particles observed with an aspect ratio of less than 1.3 was defined as the primary particle diameter, and the aspect ratio was near the maximum value. The average of the five points is obtained as the major axis length.

The deformed silica fine particles of the present invention are formed by bonding 3-20, preferably 3-10, of the silica fine particles by inorganic chemical bonds.
If the number of the fine particles in which the silica fine particles are bonded by an inorganic chemical bond is 3 to 20, the effect of improving the hardness can be obtained.

Examples of the inorganic chemical bond include an ionic bond, a metal bond, a coordination bond, and a covalent bond. Among these, bonds that do not disperse the bonded fine particles even when the deformed silica fine particles are added to a polar solvent, specifically, metal bonds, coordinate bonds, and covalent bonds are preferable, and covalent bonds are more preferable. In a conventional aggregate having no covalent bond, there is a possibility that the aggregate is separated by a physical external force (for example, a shear in stirring at the ink stage, a shear received during application of a doctor knife or the like). Chemically, there is a possibility that the aggregate is separated by an additive such as a solvent that breaks the aggregation, a binder component, or a surfactant. In addition, even when the optical sheet is formed, the aggregate is separated by a physical external force (contact by a pointed object or the like), which may cause scratches on the optical sheet. On the other hand, a covalent bond is stable because it is difficult to decompose due to physical and chemical forces.
Examples of the polar solvent include water, methanol, and lower alcohols such as ethanol and isopropanol.

The deformed silica fine particles of the present invention are superior in hardness to those obtained by bonding the reactive silica fine particles via the first binder component with the reactive functional group a. By using the reactive deformed silica fine particles having a, the optical sheet according to the present invention exhibits excellent hardness.
The reason why the deformed silica fine particles are superior in hardness than those obtained by bonding 3 to 20 of the reactive silica fine particles by the reactive functional group a is not clear, but the inorganic chemical bond of the deformed silica fine particles is an organic component. This is presumably because the rigidity is higher than the bond between functional groups.

  The method for producing irregular shaped silica fine particles is not particularly limited as long as the silica fine particles are bonded by an inorganic chemical bond, and a conventionally known method can be appropriately selected and used. For example, it can be obtained by adjusting the concentration or pH of the monodispersed silica fine particle dispersion and performing hydrothermal treatment at a high temperature of 100 ° C. or higher. At this time, if necessary, a binder component can be added to promote the binding of the silica fine particles. Further, ions may be removed by passing the silica fine particle dispersion used through an ion exchange resin. Such ion exchange treatment can promote the binding of silica fine particles. After the hydrothermal treatment, the ion exchange treatment may be performed again.

  The method of introducing the reactive functional group a into the surface of the irregular-shaped silica fine particle to obtain the reactive irregular-shaped silica fine particle may be a method of introducing the reactive functional group a into the silica fine particle of the reactive silica fine particle.

  When the first reactive silica fine particles include the reactive irregular shaped silica fine particles, in addition to the reactive irregular shaped silica fine particles, spherical reactive silica fine particles having an average primary particle diameter of 1 to 100 nm are included. Also good. When the reactive deformed silica fine particles and the spherical reactive silica fine particles are included, the reactive deformed silica fine particles are preferably contained in an amount of 50% by mass or more based on the total amount of the two types of reactive silica fine particles. The content of 80% by mass or more is more preferable from the viewpoint of improving hardness. Further, the reactive functional group a of the reactive irregular shaped silica fine particles and the reactive functional group a of the spherical reactive silica fine particles may be the same or different.

  Commercially available products of the above-mentioned reactive deformed silica fine particles include DP1039, DP1040, DP1071, DP1072, DP1073 manufactured by JGC Catalysts and Chemicals.

(First binder component)
The first binder component used in the first curable resin composition has a reactive functional group b, and crosslinks between the first binder components when cured to form a matrix of the first HC layer. It is an ingredient. Moreover, since the reactive functional group b has cross-linking reactivity with the reactive functional group a of the first reactive silica fine particles and the reactive functional group c of the second binder component described later, the reactive functional group b crosslinks with these components. Thus, a network structure is formed, and the adhesion between the first HC layer and the second HC layer and the hardness of the optical sheet are further increased.

  As the reactive functional group b, a polymerizable unsaturated group is suitably used, preferably a photocurable unsaturated group, and particularly preferably an ionizing radiation curable unsaturated group. Specific examples thereof include ethylenically unsaturated bonds such as (meth) acryloyl group, vinyl group and allyl group, and epoxy group.

  The reactive functional group b may be the same as or different from the other reactive functional groups a and c.

  The first binder component is preferably a curable organic resin, preferably a translucent material that transmits light when formed into a coating film, and an ionizing radiation that is a resin that is cured by ionizing radiation represented by ultraviolet rays or electron beams. What is necessary is just to employ | adopt suitably curable resin, other well-known curable resin, etc. according to a required performance. Examples of the ionizing radiation curable resin include acrylate-based, oxetane-based, and silicone-based resins.

  As the first binder component, one or more binder components can be used.

  The first binder component, in the first curable resin composition, if the total solid content of at least the first reactive silica fine particles is 30% by mass or more with respect to all components of the composition, The amount may be appropriately adjusted in consideration of applicability and the like. It is preferable from the point which forms the matrix of a cured film that 20-95 mass% is contained with respect to what remove | excluded the 1st reactive silica microparticles | fine-particles from the total solid of the 1st curable resin composition.

  The first binder component preferably has three or more reactive functional groups b from the viewpoint of increasing the crosslinking density.

Examples of the binder component having three or more reactive functional groups b include pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and dipentaerythritol penta (meth) acrylate. , Trimethylolpropane tri (meth) acrylate, trimethylolpropane hexa (meth) acrylate, and modified products thereof.
Examples of modified products include EO (ethylene oxide) modified products, PO (propylene oxide) modified products, CL (caprolactone) modified products, and isocyanuric acid modified products.

  As the first binder component, pentaerythritol triacrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, and dipentaerythritol pentaacrylate are preferably used, and dipentaerythritol hexaacrylate, penta Erythritol tetraacrylate and dipentaerythritol pentaacrylate are particularly preferably used.

  In addition, from the viewpoint of improving hardness in the first HC layer, as the first binder component, a polyalkylene oxide chain-containing polymer (A) represented by the following chemical formula (4) and two or more reactive functional groups It is preferable to use in combination with a compound (B) having a molecular weight b of less than 10,000.

In the chemical formula (4), X is a linear, branched, or cyclic hydrocarbon chain, either alone or in combination. The hydrocarbon chain may have a substituent, and between the hydrocarbon chains. Is a trivalent or higher valent organic group having 3 to 10 carbon atoms, excluding the substituent, which may contain different atoms. k represents an integer of 3 to 10. L _{1 to} L _k are each independently a divalent group containing one or more selected from the group consisting of an ether bond, an ester bond, and a urethane bond, or a direct bond. R _{1 to} R _k are each independently a linear or branched hydrocarbon group having 1 to 4 carbon atoms. n1, n2,... nk are independent numbers. Y _{1 to} Y _k each independently represent a compound residue having one or more reactive functional groups b.

  Presumed that the polymer (A) and the compound (B) form a crosslink with the reactive silica fine particles having other reactive functional groups and the first binder component, so that the optical sheet can be given hardness. Is done.

(Polyalkylene oxide chain-containing polymer represented by chemical formula (4) (A))
The polyalkylene oxide chain-containing polymer (A) is a polyalkylene oxide chain-containing polymer represented by the following chemical formula (4) and having a molecular weight of 1000 or more having three or more reactive functional groups b at the terminals.

In the chemical formula (4), X is a linear, branched, or cyclic hydrocarbon chain, either alone or in combination. The hydrocarbon chain may have a substituent, and between the hydrocarbon chains. Is a trivalent or higher valent organic group having 3 to 10 carbon atoms, excluding the substituent, which may contain different atoms. k represents an integer of 3 to 10. L _{1 to} L _k are each independently a divalent group containing one or more selected from the group consisting of an ether bond, an ester bond, and a urethane bond, or a direct bond. R _{1 to} R _k are each independently a linear or branched hydrocarbon group having 1 to 4 carbon atoms. n1, n2,... nk are independent numbers. Y _{1 to} Y _k each independently represent a compound residue having one or more reactive functional groups b.

In the chemical formula (4), X is a linear, branched, or cyclic hydrocarbon chain, either alone or in combination. The hydrocarbon chain may have a substituent, and between the hydrocarbon chains. Is a trivalent or higher valent organic group having 3 to 10 carbon atoms excluding the substituent. In the polyalkylene oxide chain-containing polymer (A) represented by the chemical formula (4), X has _k branch points from which the polyalkylene oxide chain (O—R _k ) _nk portion which is a linear side chain appears. Corresponds to the short main chain.

The hydrocarbon chain includes a saturated hydrocarbon such as —CH ₂ — or an unsaturated hydrocarbon such as —CH═CH—. The cyclic hydrocarbon chain may be composed of an alicyclic compound or may be composed of an aromatic compound. Further, different atoms such as O and S may be included between the hydrocarbon chains, and ether bonds, thioether bonds, ester bonds, urethane bonds, and the like may be included between the hydrocarbon chains. In addition, the hydrocarbon chain branched via a different atom with respect to a linear or cyclic hydrocarbon chain is counted as the carbon number of the substituent mentioned later.

  Specific examples of the substituent that the hydrocarbon chain may have include a halogen atom, a hydroxyl group, a carboxyl group, an amino group, an epoxy group, an isocyanate group, a mercapto group, a cyano group, a silyl group, a silanol group, and a nitro group. Group, acetyl group, acetoxy group, sulfone group and the like are mentioned, but not particularly limited. Substituents that may be present in the hydrocarbon chain include hydrocarbon chains that are branched via a hetero atom with respect to a linear or cyclic hydrocarbon chain as described above. A group (RO-, where R is a saturated or unsaturated linear, branched, or cyclic hydrocarbon chain), an alkylthioether group (RS-, where R is a saturated or unsaturated linear chain, A branched or cyclic hydrocarbon chain), an alkyl ester group (RCOO-, where R is a saturated or unsaturated linear, branched, or cyclic hydrocarbon chain). .

X is a trivalent or higher valent organic group having 3 to 10 carbon atoms excluding the substituent. When the number of carbon atoms excluding the substituent of X is less than 3, it is difficult to have three or more polyalkylene oxide chain (O—R _k ) _nk moieties that are linear side chains. On the other hand, when the number of carbon atoms excluding the substituent of X exceeds 10, the flexible portion increases and the hardness of the cured film decreases, which is not preferable. The number of carbon atoms excluding the substituent is preferably 3-7, and more preferably 3-5.

  X is not particularly limited as long as the above conditions are satisfied. For example, what has the following structure is mentioned.

  Among them, preferable structures include the above structures (x-1), (x-2), (x-3), (x-7) and the like.

  Among the raw materials for X, among others, 1,2,3-propanetriol (glycerol), trimethylolpropane, pentaerythritol, dipentaerythritol and the like are polyvalent having 3 to 10 carbon atoms having 3 or more hydroxyl groups in the molecule. Alcohols, polyvalent carboxylic acids having 3 to 10 carbon atoms having 3 or more carboxyl groups in the molecule, polyvalent amine acids having 3 to 10 carbon atoms having 3 or more amino groups in the molecule, etc. Preferably used.

In the chemical formula (4), k represents the number of polyalkylene oxide chains (O—R _k ) _{nk in} the molecule, and represents an integer of 3 to 10. If k is less than 3, that is, if there are two polyalkylene oxide chains, sufficient hardness cannot be obtained. On the other hand, if k exceeds 10, the number of flexible parts increases and the hardness of the cured film decreases, which is not preferable. The k is preferably 3-7, more preferably 3-5.

In the chemical formula (4), L _{1 to} L _k are each independently a divalent group including one or more selected from the group consisting of an ether bond, an ester bond, and a urethane bond, or a direct bond. The divalent group containing one or more selected from the group consisting of an ether bond, an ester bond, and a urethane bond is an ether bond (—O—), an ester bond (—COO—), a urethane bond (—NHCOO—). ) Itself. Since these bonds are easy to spread molecular chains and have a high degree of freedom, it is easy to achieve compatibility with other resin components.

  Examples of the divalent group containing one or more selected from the group consisting of an ether bond, an ester bond, and a urethane bond include —O—R—O— and —O (C═O) —R—O—. -O (C = O) -R- (C = O) O-,-(C = O) O-R-O-,-(C = O) O-R- (C = O) O-, — (C═O) O—R—O (C═O) —, —NHCOO—R—O—, —NHCOO—R—O (C═O) NH—, —O (C═O) NH—R —O—, —O (C═O) NH—R—O (C═O) NH—, —NHCOO—R—O (C═O) NH—, —NHCOO—R— (C═O) O— , —O (C═O) NH—R— (C═O) O—, —NHCOO—R—O (C═O) —, —O (C═O) NH—R—O (C═O) -Etc. are mentioned. Here, R represents a saturated or unsaturated, linear, branched or cyclic hydrocarbon chain.

  Specific examples of the divalent group include, for example, diols such as (poly) ethylene glycol and (poly) propylene glycol, dicarboxylic acids such as fumaric acid, maleic acid, and succinic acid, tolylene diisocyanate, hexamethylene diisocyanate, Although the residue remove | excluding active hydrogen, such as diisocyanates, such as isoboron diisocyanate, is mentioned, It is not limited to these.

In the chemical formula (4), (O—R _k ) _nk is a polyalkylene oxide chain in which alkylene oxide is a linear side chain of a repeating unit. Here, R _{1 to} R _k are each independently a linear or branched hydrocarbon group having 1 to 4 carbon atoms. Examples of the alkylene oxide include methylene oxide, ethylene oxide, propylene oxide, isobutylene oxide, and the like, and ethylene oxide and propylene oxide which are linear or branched hydrocarbon groups having 2 to 3 carbon atoms are preferably used.

N1, n2... Nk, which are the number of repeating units of alkylene oxide R _k —O, are independent numbers. n1, n2,... nk are not particularly limited as long as the weight average molecular weight as a whole molecule is 1000 or more. n1, n2... nk may be different from each other, but it is preferable that the chain lengths are substantially the same from the viewpoint of suppressing cracks while maintaining the hardness when the hard coat layer is formed. Therefore, the difference between n1, n2,... Nk is preferably about 0 to 100, more preferably about 0 to 50, and particularly preferably about 0 to 10.
From the viewpoint of suppressing cracks while maintaining the hardness when the HC layer is formed, n1, n2,... Nk are each preferably a number of 2 to 500, and more preferably a number of 2 to 300. .

Y _{1 to} Y _k each independently represent a reactive functional group b or a compound residue having one or more reactive functional groups b. This results in three or more reactive functional groups b at the ends of the polyalkylene oxide chain-containing polymer.
When Y _{1 to} Y _k are the reactive functional group b itself, examples of Y _{1 to} Y _k include polymerizable unsaturated groups such as (meth) acryloyl groups and vinyl groups (CH ₂ ═CH—). .

Moreover, as the reactive functional group b in the case where Y _{1 to} Y _k are compound residues having one or more reactive functional groups b, for example, a (meth) acryloyloxy group bH ₂ = CR- (where R May be a polymerizable unsaturated group such as a hydrocarbon group. If the reactive functional group b is appropriately selected so that it can react with the reactive silica fine particles and the compound (B) described later, the compound residue is not particularly limited. When Y _{1 to} Y _k is a compound residue, the number of reactive functional groups b possessed by Y _{1 to} Y _k may be one, but two or more can further increase the crosslinking density. From the viewpoint of scratch resistance and hardness when used as a hard coat layer.

When Y _{1 to} Y _k are compound residues having one or more reactive functional groups b, the compound residues are separated from at least one or more reactive functional groups b and the reactive functional groups b. Furthermore, it is a residue obtained by removing the reactive substituent or a part of the reactive substituent (such as hydrogen) from the compound having the reactive substituent.
For example, as the compound residue having an ethylenically unsaturated group, specifically, for example, a reactive substituent other than the ethylenically unsaturated group of the following compound or a part of the reactive substituent (such as hydrogen) is excluded. Residue. Examples include (meth) acrylic acid, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and pentaerythritol tri (meth) acrylate, but are not limited thereto.

  The molecular weight of the polyalkylene oxide chain-containing polymer (A) used in the present invention is 1000 or more, more preferably 5000 or more, and particularly preferably 10,000 from the viewpoint of imparting flexibility to the cured film and preventing cracks. That's it.

As a commercial item containing the polyalkylene oxide chain containing polymer (A) represented by the above chemical formula (4), for example, trade name Diabeam UK-4153 (manufactured by Mitsubishi Rayon; in chemical formula (4), X is (x -7), k is 3, L _{1 to} L ₃ are each a direct bond, R _{1 to} R ₃ are each ethylene, the total of n1, n2, and n3 is 20, and Y _{1 to} Y ₃ are each an acryloyloxy group. And the like.

  It is preferable that content of the said polymer (A) is 5-100 mass parts with respect to 100 mass parts of compounds (B) mentioned later, and it is still more preferable that it is 10-50 mass parts. If the content of the polymer (A) is 5 parts by mass or more with respect to 100 parts by mass of the compound (B) described later, flexibility and restorability can be imparted to the cured film, and if it is 100 parts by mass or less, The hardness of the cured film can be maintained.

(Compound (B) having two or more reactive functional groups b and a molecular weight of less than 10,000)
The compound (B) having a molecular weight of less than 10,000 having two or more reactive functional groups b improves the hardness of the first HC layer in combination with the first reactive silica fine particles. It is given. In addition, what has the structure of the said polymer (A) is remove | excluded from the compound (B) which has two or more reactive functional groups b and whose molecular weight is less than 10,000.
As the compound (B), one kind may be used alone, or two or more kinds may be appropriately mixed and used.
In the compound (B) having a molecular weight of less than 10,000 having two or more reactive functional groups b, the number of reactive functional groups b contained in one molecule is three or more, which increases the crosslinking density of the cured film. From the viewpoint of imparting hardness. Here, when the compound (B) is an oligomer having a molecular weight distribution, the number of reactive functional groups b is represented by an average number.
Moreover, it is preferable that the molecular weight of a compound (B) is less than 5,000 from the point of a hardness improvement.

Specific examples are given below, but the compound (B) used in the present invention is not limited thereto.
As a specific example having a polymerizable unsaturated group, as a polyfunctional (meth) acrylate monomer having two or more polymerizable unsaturated groups in one molecule, for example, 1,6-hexanediol di (meth) acrylate, Bifunctional or reactive functional groups such as neopentyl glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, and isocyanuric acid ethylene oxide-modified di (meth) acrylate; (Meth) acrylate and its EO, PO, epichlorohydrin modified product, pentaerythritol tri (meth) acrylate, glycerol tri (meth) acrylate, and its EO, PO, epichlorohydrin modified product, isocyanuric acid EO modified tri (meth) acrylate ( east Synthetic Aronix M-315, etc.), tris (meth) acryloyloxyethyl phosphate, hydrogen phthalate- (2,2,2-tri- (meth) acryloyloxymethyl) ethyl, glycerol tri (meth) acrylate, and its Trifunctional (meth) acrylate compounds such as EO, PO, epichlorohydrin modified products; pentaerythritol tetra (meth) acrylate and tetrafunctional (meth) such as EO, PO, epichlorohydrin modified products, ditrimethylolpropane tetra (meth) acrylate Acrylate compound; Dipentaerythritol penta (meth) acrylate and pentafunctional (meth) acrylate compound such as EO, PO, epichlorohydrin, fatty acid, alkyl, urethane modified product; dipentaerythritol hexa (meth) acrylate Relate, and its EO, PO, epichlorohydrin, fatty acid, alkyl, urethane modified product, sorbitol hexa (meth) acrylate, and its EO, PO, epichlorohydrin, fatty acid, alkyl, urethane modified product, etc. Can be mentioned.

  Commercially available products can be used as the trifunctional or higher acrylate resin. Specifically, KAYARAD and KAYAMER series (for example, DPHA, PET30, GPO303, TMPTA, THE330, TPA330, manufactured by Nippon Kayaku Co., Ltd.) D310, D330, PM2, PM21, DPCA20, DPCA30, DPCA60, DPCA120); Aronix series manufactured by Toagosei Co., Ltd. (for example, M305, M309, M310, M315, M320, M327, M350, M360, M402, M408, M450, M7100, M7300K, M8030, M8060, M8100, M8530, M8560, M9050); NK ester series (for example, TMPT, A-TMPT, A-TMM-) manufactured by Shin-Nakamura Chemical Co., Ltd. A-TMM3L, A-TMMT, A-TMPT-6EO, A-TMPT-3CL, A-GLY-3E, A-GLY-6E, A-GLY-9E, A-GLY-11E, A-GLY-18E , A-GLY-20E, A-9300, AD-TMP-4CL, AD-TMP); NK Economer series manufactured by Shin-Nakamura Chemical Co., Ltd. (for example, ADP51, ADP33, ADP42, ADP26, ADP15); New frontier series (for example, TMPT, TMP3, TMP15, TMP2P, TMP3P, PET3, TEICA) manufactured by Ichi Kogyo Seiyaku Co., Ltd .; Ebecryl series (for example, TMPTA, TMPTAN, 160, manufactured by Daicel UCB) TMPEOTA, OTA480, 53, PETIA, 2047, 40, 1 0, 1140, PETAK, DPHA); SARTOMER CD501, CD9021, CD9052, SR351, SR351HP, SR351LV, SR368, SR368D, SR415, SR444, SR454, SR454HP, SR492, SR499, SR502, SR90020, SR9020SR SR9035, CD9051, SR350, SR9009, SE9011, SR295, SR355, SR399, SR399LV, SR494, SR9041 and the like.

  Examples of (meth) acrylate oligomers (or prepolymers) include epoxy (meth) acrylates obtained by addition reaction of glycidyl ether and a monomer having (meth) acrylic acid or a carboxylate group; polyols and polyisocyanates; (Meth) acrylates obtained by an addition reaction between a reaction product of (1) and a hydroxyl group-containing (meth) acrylate; polyesters obtained by esterification of a polyester polyol comprising a polyol and a polybasic acid and (meth) acrylic acid Examples of acrylates include polybutadiene (meth) acrylate, which is a (meth) acrylic compound having a polybutadiene or hydrogenated polybutadiene skeleton. When the reactive functional group b which the essential component in the present invention has is a polymerizable unsaturated group, urethane (meth) acrylate is particularly preferably used from the viewpoint of imparting hardness and flexibility to the cured film.

Examples of the glycidyl ether used in the epoxy (meth) acrylates include 1,6-hexane diglycidyl ether, polyethylene glycol glycidyl ether, bisphenol A type epoxy resin, naphthalene type epoxy resin, cardo epoxy resin, and glycerol triglycidyl ether. And phenol novolac type epoxy resins.
Examples of the polyol used in the urethane (meth) acrylates include 1,6-hexane diglycidyl ether, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polycaprolactone diol, polycarbonate diol, polybutadiene polyol, and polyester diol. Etc. Examples of the polyisocyanate used in the urethane (meth) acrylates include tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, tetramethylxylene diisocyanate, hexamelletin diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and the like. Examples of the (meth) acrylate containing a hydroxyl group used in the urethane (meth) acrylates include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and pentaerythritol. (Meth) acrylate, caprolactone-modified 2-hydroxyethyl (meth) acrylate and the like.
Examples of the polyol for forming the polyester polyol used in the polyester acrylates include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, neopentyl glycol, 1,4-butanediol, trimethylolpropane, and pentaerythritol. Examples of the polybasic acid include succinic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid.

  Moreover, as a compound (B) used for this invention, the polymer represented by following Chemical formula (5) whose molecular weight is less than 10,000 can also be used.

In chemical formula (5), D represents a linking group having 1 to 10 carbon atoms, and q represents 0 or 1. R represents a hydrogen atom or a methyl group. E represents a polymerization unit of an arbitrary vinyl monomer, and may be composed of a single component or a plurality of components. o and p are mol% of each polymerized unit. p may be 0.

  D in the chemical formula (5) represents a linking group having 1 to 10 carbon atoms, more preferably a linking group having 1 to 6 carbon atoms, particularly preferably a linking group having 2 to 4 carbon atoms, which is linear. May have a branched structure, may have a ring structure, and may have a heteroatom selected from O, N, and S.

Preferred examples of the linking group D in the chemical formula (5) include * — (CH ₂ ) ₂ —O — **, * — (CH ₂ ) ₂ —NH — **, * — (CH ₂ ) ₄ —O. _{- **, * - (CH 2} ) 6 -O - **, * - (CH 2) 2 -O- (CH) 2 -O - **, * - CONH- (CH 2) 3 -O- * *, * —CH ₂ CH (OH) CH ₂ —O — **, * —CH ₂ CH ₂ OCONH (CH ₂ ) ₃ —O — ** and the like. Here, * represents a connecting site on the polymer main chain side, and ** represents a connecting site on the (meth) acryloyl group side.

  In chemical formula (5), R represents a hydrogen atom or a methyl group, and is more preferably a hydrogen atom from the viewpoint of curing reactivity.

  In the chemical formula (5), o may be 100 mol%, that is, a single polymer. Moreover, even if o is 100 mol%, the copolymer in which 2 or more types of polymerization units containing the (meth) acryloyl group represented by o mol% were used may be used. The ratio of o and p is not particularly limited and can be appropriately selected from various viewpoints such as hardness, solubility in a solvent, and light transmittance.

  In chemical formula (5), E represents a polymerization unit of an arbitrary vinyl monomer, and is not particularly limited, and can be appropriately selected from various viewpoints such as hardness, solubility in a solvent, and light transmittance. It may be composed of a single or a plurality of vinyl monomers.

  For example, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, t-butyl vinyl ether, cyclohexyl vinyl ether, isopropyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, glycidyl vinyl ether, allyl vinyl ether, vinyl acetate, vinyl propionate, vinyl butyrate, etc. (Meth) acrylates such as vinyl esters, methyl (meth) acrylate, ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, glycidyl methacrylate, allyl (meth) acrylate, (meth) acryloyloxypropyltrimethoxysilane, Styrene derivatives such as styrene and p-hydroxymethyl styrene, and unsaturated hydrocarbons such as crotonic acid, maleic acid and itaconic acid. Mention may be made of carbon acid and derivatives thereof.

  Moreover, the reactive oligomer which has an ethylenically unsaturated bond in the terminal and side chain whose weight average molecular weight is less than 10,000 can also be used. As the reactive oligomer, the skeleton component is poly (meth) acrylate methyl, polystyrene, poly (meth) butyl acrylate, poly (acrylonitrile / styrene), poly ((meth) acrylate 2-hydroxymethyl / (meth) Methyl acrylate), poly (2-hydroxymethyl (meth) acrylate / butyl (meth) acrylate), and copolymers of these resins and silicone resins.

  Commercially available products can be used for the above compounds. As urethane acrylate having a weight average molecular weight of less than 10,000 and having two or more polymerizable unsaturated groups, Kyoeisha Chemical Co., Ltd. trade names AH-600, AT-600, UA-306H, UA-306T, UA-306I etc. are mentioned. The urethane (meth) acrylate suitably used in combination with the polymer (A) is obtained by reacting a monomer or multimer of isophorone diisocyanate, a pentaerythritol polyfunctional acrylate, and a dipentaerythritol polyfunctional acrylate. A urethane (meth) acrylate is mentioned. As a commercial item of the said urethane (meth) acrylate, brand name UV-1700B (made by Nippon Synthetic Chemical Industry Co., Ltd.) is mentioned, for example.

  A commercially available product can be used as the urethane (meth) acrylate resin, and specific examples include the purple light series manufactured by Nippon Synthetic Chemical Industry Co., Ltd., such as UV1700B, UV6300B, UV765B, UV7640B, and UV7600B; Art Resin series manufactured by Kogyo Co., Ltd., such as Art Resin HDP, Art Resin UN 9000H, Art Resin UN 3320HA, Art Resin UN 3320HB, Art Resin UN 3320HC, Art Resin UN 3320HS, Art Resin UN901M, Art Resin UN902MS, Art Resin UN903, etc. And UA100H, U4H, U6H, U15HA, UA32P, U6LPA, U324A, U9HAMI, etc. manufactured by Shin-Nakamura Chemical Co., Ltd .; Ebecryl series manufactured by, for example, 1290, 5129, 254, 264, 265, 1259, 1264, 4866, 9260, 8210, 204, 205, 6602, 220, 4450, etc .; Arakawa Chemical Industries, Ltd. Beamset series manufactured by, for example, 777, 577BV, 777AK, etc .; RQ series manufactured by Mitsubishi Rayon Co., Ltd .; unidic series manufactured by DIC Corporation, etc .; DPHA40H (Nippon Kayaku) CN9006, CN968 (made by SARTOMER), etc. are mentioned. Of these, UV1700B (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), DPHA40H (manufactured by Nippon Kayaku Co., Ltd.), Art Resin HDP (manufactured by Negami Industrial Co., Ltd.), Beam Set 577 (Arakawa Chemical Industries, Ltd.) )), U15HA (manufactured by Shin-Nakamura Chemical Co., Ltd.) and the like.

  Moreover, as an epoxy acrylate having a weight average molecular weight of less than 10,000 and having two or more polymerizable unsaturated groups, trade name SP series (SP-4060, 1450, etc.), VR series, manufactured by Showa Polymer Co., Ltd. (VR-60, 1950; VR-90, 1100, etc.), etc .; Nippon Synthetic Chemical Industry Co., Ltd., trade name UV-9100B, UV-9170B, etc .; Shin-Nakamura Chemical Co., Ltd., trade name EA-6320 / PGMAc EA-6340 / PGMAc and the like.

  Moreover, as a reactive oligomer having a weight average molecular weight of less than 10,000 and having two or more polymerizable unsaturated groups, trade name Macromonomer Series AA-6, AS-6, AB- manufactured by Toagosei Co., Ltd. 6, AA-714SK and the like.

In consideration of the curling property and cracking property of the hard coat layer, those having a repeating unit similar to the chemical formula (5) and having a molecular weight of 10,000 or more and less than 100,000 may be used as a binder component.
Examples of the binder component having a molecular weight of 10,000 or more and less than 100,000 include BS371, BS371MLV, DK1, DK2, and DK3 manufactured by Arakawa Chemical Industries, Ltd.

(Other components of the first curable resin composition)
The first curable resin composition has a total solid content of 30% by mass or more with respect to all components of the composition in order to prevent mixing of the entire composition with the second curable resin composition. If it is this range, a solvent, a polymerization initiator, an antistatic agent, an anti-glare agent, etc. can also be suitably added to a 1st curable resin composition other than the said component. Furthermore, various additives, such as a reactive or non-reactive leveling agent and various sensitizers, may be mixed. When an antistatic agent and / or an antiglare agent are included, antistatic properties and / or antiglare properties can be further imparted to the first HC layer.

(Solvent of the first curable resin composition)
The solvent is appropriately selected without particular limitation as long as the total solid content including at least the first reactive silica fine particles and the first binder component with respect to all components of the first curable resin composition is 30% by mass or more. Can be used.

  Specific examples of the solvent include methanol, ethanol, normal propanol, isopropanol (IPA), normal butanol, sec-butanol, isobutanol, tert-butanol, methyl glycol, propylene glycol monomethyl ether (PGME), methyl glycol acetate, methyl cellosolve. , Alcohols such as ethyl cellosolve, butyl cellosolve; ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, diacetone alcohol; methyl formate, methyl acetate, ethyl acetate, ethyl lactate, butyl acetate, etc. Esters; nitrogen-containing compounds such as nitromethane, N-methylpyrrolidone, N, N-dimethylformamide; diisopropyl ether, tetrahydrofuran , Dioxane, dioxolane and the like; methylene chloride, chloroform, trichloroethane, halogenated hydrocarbons such as tetrachloroethane; dimethylsulfoxide, other objects, such as propylene carbonate; or mixtures thereof.

It is one or more impermeable solvents selected from the group consisting of MIBK, PGME, normal propanol, isopropanol, normal butanol, sec-butanol, isobutanol, and tert-butanol from the viewpoint of improving the hardness of the optical sheet. Is preferred. By using the non-permeable solvent, the first binder component does not penetrate into the light-transmitting resin base material, so that the hardness of the first HC layer can be increased.
In addition, in this invention, osmosis | permeation means dissolving or swelling a transparent resin base material.

The solvent of the first curable resin composition has a low boiling point or high volatility so that the viscosity of the curable resin composition immediately after coating is increased by volatilization of the solvent, and the first and second curable resin compositions This is preferable because the entire mixing can be further suppressed, the generation of coating streaks can be suppressed, and the functional separation can be reliably performed.
As such a solvent, a solvent having a boiling point of 120 ° C. or less is preferable, and examples thereof include methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), isobutyl acetate, toluene, and ethyl acetate.

(Polymerization initiator)
In order to initiate or promote the reaction of the radical polymerizable functional group or the cationic polymerizable functional group, a radical polymerization initiator, a cationic polymerization initiator, a radical and a cationic polymerization initiator, etc. are appropriately selected and used as necessary. Also good. These polymerization initiators are decomposed by light irradiation and / or heating to generate radicals or cations to advance radical polymerization and cationic polymerization.

Any radical polymerization initiator may be used as long as it can release a substance that initiates radical polymerization by light irradiation and / or heating. For example, examples of the photo radical polymerization initiator include imidazole derivatives, bisimidazole derivatives, N-aryl glycine derivatives, organic azide compounds, titanocenes, aluminate complexes, organic peroxides, N-alkoxypyridinium salts, thioxanthone derivatives, and the like. More specifically, 1,3-di (tert-butyldioxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetrakis (tert-butyldioxycarbonyl) benzophenone, 3-phenyl-5- Isoxazolone, 2-mercaptobenzimidazole, bis (2,4,5-triphenyl) imidazole, 2,2-dimethoxy-1,2-diphenylethane-1-one (trade name Irgacure 651, Ciba Japan Co., Ltd.) 1-hydroxy-cyclohexyl-phenyl- T (trade name Irgacure 184, manufactured by Ciba Japan Co., Ltd.), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one (trade names Irgacure 369, Ciba Japan ( Co., Ltd.), bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium) (trade name Irgacure 784, manufactured by Ciba Japan Co., Ltd.), etc., but is not limited thereto.

  In addition to the above, commercially available products can be used. Specifically, Irgacure 907, Irgacure 379, Irgacure 819, Irgacure 127, Irgacure 500, Irgacure 754, Irgacure 250, Irgacure 1800, Irgacure 1870 manufactured by Ciba Japan Co., Ltd. , Irgacure OXE01, DAROCUR TPO, DAROCUR1173, Japan Siber Hegner Co., Ltd. of SpeedcureMBB, SpeedcurePBZ, SpeedcureITX, SpeedcureCTX, SpeedcureEDB, Esacure ONE, Esacure KIP150, Esacure KTO46, manufactured by Nippon Kayaku Co., of (stock) KAYACURE DETX-S, KAYACURE CTX , KAYACURE BMS, K YACURE DMBI, and the like.

Moreover, the cationic polymerization initiator should just be able to discharge | release the substance which starts cationic polymerization by light irradiation and / or a heating. Examples of the cationic polymerization initiator include sulfonic acid ester, imide sulfonate, dialkyl-4-hydroxysulfonium salt, arylsulfonic acid-p-nitrobenzyl ester, silanol-aluminum complex, (η ⁶ -benzene) (η ⁵ -cyclopentadidiene). Enyl) iron (II) and the like are exemplified, and more specifically, benzoin tosylate, 2,5-dinitrobenzyl tosylate, N-tosiphthalimide and the like are exemplified, but not limited thereto.

  Examples of radical polymerization initiators used as cationic polymerization initiators include aromatic iodonium salts, aromatic sulfonium salts, aromatic diazonium salts, aromatic phosphonium salts, triazine compounds, iron arene complexes, and the like. More specifically, iodonium chloride such as diphenyliodonium, ditolyliodonium, bis (p-tert-butylphenyl) iodonium, bis (p-chlorophenyl) iodonium, bromide, borofluoride, hexafluorophosphate salt, hexafluoro Iodonium salts such as antimonate salts, chlorides of sulfonium such as triphenylsulfonium, 4-tert-butyltriphenylsulfonium, tris (4-methylphenyl) sulfonium, bromides, borofluorides, hexaf Sulfonium salts such as orophosphate salts and hexafluoroantimonate salts, 2,4,6-tris (trichloromethyl) -1,3,5-triazine, 2-phenyl-4,6-bis (trichloromethyl) -1, 2,4,6-substituted-1,3,5 triazine compounds such as 3,5-triazine, 2-methyl-4,6-bis (trichloromethyl) -1,3,5-triazine, etc. It is not limited to these.

  When a polymerization initiator is used, it is more preferable that it is contained so that it may become 1-12 mass% and 3-6 mass% with respect to the total solid of a 1st curable resin composition.

(Antistatic agent)
Specific examples of the antistatic agent include quaternary ammonium salts, pyridinium salts, various cationic compounds having cationic groups such as primary to tertiary amino groups, sulfonate groups, sulfate ester bases, and phosphate ester bases. , Anionic compounds having an anionic group such as phosphonate group, amphoteric compounds such as amino acid series and aminosulfate ester series, nonionic compounds such as amino alcohol series, glycerin series and polyethylene glycol series, and alkoxides of tin and titanium And metal chelate compounds such as acetylacetonate salts thereof, and compounds obtained by increasing the molecular weight of the compounds listed above. In addition, it has a tertiary amino group, a quaternary ammonium group, or a metal chelate portion, and has a monomer or oligomer that can be polymerized by ionizing radiation, or a polymerizable functional group that can be polymerized by ionizing radiation, and Polymerizable compounds such as organometallic compounds such as coupling agents can also be used as antistatic agents.

  Examples of the antistatic agent include conductive polymers. The conductive polymer is not particularly limited. For example, aromatic conjugated poly (paraphenylene), heterocyclic conjugated polypyrrole, polythiophene, aliphatic conjugated polyacetylene, heteroatom-containing polyaniline, mixed type Conjugated poly (phenylene vinylene), a double chain conjugated system that has a plurality of conjugated chains in the molecule, and a conductive polymer that is a polymer obtained by grafting or block-copolymerizing the conjugated polymer chain to a saturated polymer. And the like.

Moreover, electroconductive fine particles are mentioned as another example of the said antistatic agent. Specific examples of the conductive fine particles include those made of a metal oxide. Examples of such metal oxides include ZnO (refractive index 1.90, the numerical value in parentheses below represents the refractive index), CeO ₂ (1.95), Sb ₂ O ₂ (1.71), SnO. ₂ (1.997), indium tin oxide (1.95) often referred to as ITO, In ₂ O ₃ (2.00), Al ₂ O ₃ (1.63), antimony-doped tin oxide (abbreviation) ATO, 2.0), aluminum-doped zinc oxide (abbreviation: AZO, 2.0), and the like. The conductive fine particles preferably have an average particle size of 0.1 nm to 0.1 μm. By being within such a range, when the conductive fine particles are dispersed in a binder, a composition capable of forming a highly transparent film having almost no haze and good total light transmittance can be obtained.

  When an antistatic agent is used, it is preferable that 1-30 mass parts is contained with respect to 100 mass parts of 1st binder components.

(Anti-glare agent)
Examples of the antiglare agent include fine particles, and the shape of the fine particles may be a true sphere or an ellipse, and preferably a true sphere. The fine particles may be inorganic or organic, but those formed of an organic material are preferred. The fine particles exhibit anti-glare properties, and preferably have light-transmitting properties. Specific examples of the fine particles include plastic beads, and more preferably those having optical transparency. Specific examples of plastic beads include styrene beads (refractive index 1.59), melamine beads (refractive index 1.57), acrylic beads (refractive index 1.49), acrylic-styrene beads (refractive index 1.54), Examples thereof include polycarbonate beads and polyethylene beads. The addition amount of the fine particles is preferably 0 to 30 parts by mass with respect to 100 parts by mass of the resin composition.

(Leveling agent)
A leveling agent can be added to the first curable resin composition of the present invention, and among them, it is preferable to add a fluorine or silicone leveling agent. The first curable resin composition to which the leveling agent is added can impart coating stability, slipperiness, antifouling property, and scratch resistance to the coating film surface during application or drying.

  In an optical sheet manufactured using a conventional method of laminating a hard coat layer by half-cure, a leveling agent is contained in the lower curable resin composition, and the upper curable resin composition is antifouling. When a functional additive such as an agent and a lubricant is contained, the entire upper layer and lower layer curable resin composition is mixed, so that the lower layer side leveling agent is the upper layer side curable resin composition. It was mixed in things. However, when the mixing occurs, the leveling agent sometimes hinders the function of the functional additive such as an antifouling agent or a lubricant.

  The reason for this is not clear, but antifouling agents and lubricants serve to roughen the surface of the layer, while leveling agents serve to smooth the surface of the layer and therefore cancel each other's effects. It is guessed.

  On the other hand, in the optical sheet according to the present invention, the mixing of the entire applied first and second curable resin compositions is suppressed, and the contact portions of the two compositions are appropriately mixed and irradiated with light. Since the first and second HC layers are formed by curing, the first curable resin composition contains a leveling agent, and the second curable resin composition contains an antifouling agent, a lubricant, etc. Even if a functional additive is contained, functional separation is possible.

  As addition amount of a leveling agent, 0-0.5 mass% is preferable with respect to the total solid of a 1st curable resin composition, and 0-0.2 mass% is more preferable.

The leveling agent may or may not have an ionizing radiation curable group.
A commercially available leveling agent can also be used. Examples of commercially available leveling agents that can be used in the present invention include the following.

As a commercially available leveling agent which does not have an ionizing radiation curable group, Megafac series made by DIC Corporation (MCF350-5, F472, F476, F445, F444, F443, F178, F470, F475, F479, F477, F482) , F486, TF1025, F478, F178K, etc.); X22-3710, X22-162C, X22-3701E, X22160AS, X22170DX, X224015, X22176DX, X22-176F, X224272, KF8001, X22-2000 manufactured by Shin-Etsu Chemical Co., Ltd. Etc .; Chisso Corporation FM4421, FM0425, FMDA26, FS1265, etc .; Toray Dow Corning Corporation BY16-750, BY16880, BY16848, SF8427, SF842 , SH3746, SH8400, SF3771, SH3749, SH3748, SH8410, etc .; TSF series manufactured by Momentive Performance Materials Japan (TSF4460, TSF4440, TSF4445, TSF4450, TSF4446, TSF4453, TSF4452, TSF4770, FSF4770, etc.) SILWET Series (SILWETL77, SILWETL2780, SILWETL7608, SILWETL7001, SILWETL7002, SILWETL7087, SILWETL7200, SILWETL7210, SILWETL7220, SILWETL7230, SILWETL775, SILWETL775, SILWETL775 L7602, SILWETL7604, SILWETL7604, SILWETL7605, SILWETL7607, SILWETL7622, SILWETL7644, SILWETL7650, SILWETL7657, SILWETL8500, SILWETL8600, SILWETL8610, SILWETL8620, SILWETL720) and the like.
Also, Neos's Fantient Series (FTX218, 250, 245M, 209F, 222F, 245F, 208G, 218G, 240G, 206D, 240D, etc.), KB Series, etc., BYK333, manufactured by BYK Japan, 300, etc., Kyoeisha Chemical Co., Ltd. KL600 etc. are also mentioned.

  X22-163A, X22-173DX, X22-163C, KF101, X22164A, X24-8201, X22174DX, X22164C, X222426, X222445, X222457, X222245, manufactured by Shin-Etsu Chemical Co., Ltd., as those having ionizing radiation curable groups X22245, X221602, X221603, X22164E, X22164B, X22164C, X22164D, TM0701, etc .; Chisso Corporation Silaplane series (FM0725, FM0721, FM7725, FM7721, FM7726, FM7727, etc.); SF8411, SF8413, BY16-152D, BY16-152, BY16-152C, 8388A, etc .; manufactured by Shin-Nakamura Chemical Co., Ltd. SUA1900L10, SUA1900L6, etc .; Ebecryl 1360, Ebecryl 350, KRM7039, KRM7734, etc. manufactured by Daicel-Cytec Corporation; TEGO Rad2100, 2200N, 2500, 2600, 2700, etc. manufactured by Evonik Degussa Japan Co., Ltd. ; H512X, H513X, H514X, etc. manufactured by Mitsubishi Chemical Corporation; OPTOOL DAC manufactured by Daikin Industries, Ltd .; UT3971, UT4315, UT4313 manufactured by Nihon Gosei Co., Ltd .; Defenser series manufactured by DIC Corporation (TF3001, TF3000) , TF3004, TF3028, TF3027, TF3026, TF3025, etc.), RS series (RS71, RS101, RS102, RS103, RS104, RS105) BYK3500 manufactured by BYK Japan, Inc .; Light Procoat AFC3000 manufactured by Kyoeisha Chemical Co., Ltd .; KNS5300 manufactured by Shin-Etsu Silicone; UVHC1105, UVHC8550 manufactured by Momentive Performance Materials Japan; Nippon Paint Co., Ltd. ) Manufactured ACS-1122, Ripelcoat series, and the like.

(Second hard coat layer)
The second hard coat layer of the present invention includes a second binder component having a reactive functional group c, and the total solid content with respect to all components of the second curable resin composition is 30% by mass or more. It consists of a cured product of a second curable resin composition.

  The second HC layer is a layer provided on the opposite side of the first HC layer from the light-transmitting resin substrate, and is formed simultaneously with the first HC layer by light irradiation.

  Since the second binder component has reactive functional groups capable of crosslinking reaction between the same and different types of reactive functional groups including the first reactive silica fine particles and the first binder component, In addition to increasing the crosslink density and contributing to the improvement of the hardness of the second HC layer, the first reactive silica fine particles and the first binder component are also cross-linked at the boundary with the first HC layer applied and cured simultaneously. It reacts, and contributes also to the adhesive improvement of a 1st HC layer and a 2nd HC layer.

  The film thickness of the second HC layer is not particularly limited, and may be appropriately adjusted according to the required performance of the optical sheet, and is preferably 5 to 20 μm. Further, the total thickness of the first HC layer and the second HC layer is preferably 10 to 40 μm. When the sum is 10 μm or more, the effect of the present invention due to the improvement in hardness is easily exhibited. When the sum is thicker than 40 μm, the curl of the optical sheet becomes tight and cracks are likely to occur. In addition, the cost increases.

  Hereinafter, the 2nd curable resin composition which hardens | cures and becomes the 2nd HC layer of this invention is demonstrated.

(Second curable resin composition)
The second curable resin composition of the present invention includes a second binder component having a reactive functional group c.

  In the 2nd curable resin composition, the sum total of solid content is 30 mass% or more with respect to the whole component. The solid content of the second curable resin composition includes at least a second binder component. The total solid content is 40 to 60% by mass from the viewpoint of improving applicability and suppressing the occurrence of coating streaks due to the mixing of the entire first and second curable resin compositions and maintaining good appearance. More preferred. If it is less than 30% by mass, the first curable resin composition and the second curable resin composition are mixed together, and the functions such as hardness and flexibility of the first HC layer and the second HC layer are mixed. Separation is impossible, coating streaks occur, and the appearance deteriorates.

  The second curable resin composition has a total solid content of 30% by mass or more with respect to all components of the composition in order to prevent mixing of the entire composition with the first curable resin composition. In this range, in addition to the second binder component in the second curable resin composition, an antiglare agent, an antifouling agent and an antistatic agent for the purpose of imparting functionality, and a leveling agent or solvent for controlling coating suitability. Further, for the purpose of preventing blocking, it may contain an easy lubricant and the like.

(Second binder component)
The second binder component used in the second curable resin composition has a reactive functional group c and crosslinks between the second binder components when cured to form a matrix for the second HC layer. It is an ingredient. In addition, since the reactive functional group c has cross-linking reactivity with other reactive functional groups a and b, it crosslinks with these components to form a network structure, and the first HC layer and the second HC layer. The adhesion and the hardness of the optical sheet are further increased.

  The type and number of reactive functional groups of the second binder component and the type of the second binder component are the same as those of the first binder component. The first binder component and the second binder component may be the same or different.

  In the second curable resin composition, the amount of the second binder component is appropriately adjusted in consideration of applicability and the like if the total solid content is 30% by mass or more with respect to all components of the composition. Can be used. It is preferable that 20-100 mass% is contained with respect to the total solid of a 2nd curable resin composition.

(Other components of the second curable resin composition)
The second curable resin composition has a total solid content of 30% by mass or more with respect to all components of the composition in order to prevent mixing of the entire composition with the first curable resin composition. Within this range, in addition to the second binder component in the second curable resin composition, the same solvent as the first curable resin composition, second reactive silica fine particles, polymerization initiator, antistatic An agent, an antiglare agent, an antifouling agent, a lubricant, and the like can be appropriately added. Furthermore, various additives such as various sensitizers may be mixed. When an antistatic agent and / or an antiglare agent are included, antistatic properties and / or antiglare properties can be further imparted to the second HC layer.

The solvent can be appropriately selected and used without particular limitation as long as the total solid content including at least the second binder component with respect to all components of the second curable resin composition is 30% by mass or more.
Examples thereof include solvents such as methyl isobutyl ketone, propylene glycol monomethyl ether, normal propanol, isopropanol, normal butanol, sec-butanol, isobutanol, and tert-butanol. Further, ketone solvents such as methyl ethyl ketone and ester solvents such as ethyl acetate are also included.

  As the solvent for the second curable resin composition, those mentioned for the first curable resin composition can be used. A solvent having a boiling point of 120 ° C. or lower is preferable, and examples thereof include methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), isobutyl acetate, toluene, and ethyl acetate.

(Second reactive silica fine particles)
The second reactive silica fine particles have a reactive functional group d having cross-linking reactivity with other reactive functional groups a to c on the surface of the silica fine particles having an average primary particle diameter of 1 to 100 nm, When the second curable resin composition is cured to form a second HC layer, it undergoes a crosslinking reaction with these crosslinkable components, and the adhesion between the first HC layer and the second HC layer, the optical sheet Contributes to improved hardness. The second reactive silica fine particles can be used by appropriately adjusting according to the required performance of the optical sheet, even if the second reactive silica fine particles are not contained in the second curable resin composition. good.

  As for the second reactive silica fine particles, the average primary particle size, the type of the reactive functional group d, and the modification method thereof are the same as those of the first reactive silica fine particles. The first reactive silica fine particles and the second reactive silica fine particles may be the same or different.

  The ratio of the content of the second reactive silica fine particles to the total solid content of the second curable resin composition may be appropriately adjusted according to the required physical properties of the optical sheet. From the viewpoint of improving hardness, the content is preferably 50% by mass or less, and more preferably 0 to 30% by mass. When it exceeds 50% by mass, the flexibility of the surface layer is deteriorated, and the hardness of the second HC layer may be lowered. Further, when the saponification treatment is carried out, the silica fine particles which are hardened by the reactive silica fine particles are undesirably dropped and outflowed.

  In a preferred embodiment of the optical sheet according to the present invention, the second curable resin composition does not contain reactive silica fine particles, and the solid content mainly contains the second binder component. Forming the second HC layer made of a cured product of the resin composition ensures flexibility due to the upper second HC layer not containing silica fine particles, and the lower first HC containing silica fine particles. The layer functions as a base layer, and is preferable in that the first and second HC layers are combined to exhibit excellent hardness.

(Anti-fouling agent)
The antifouling agent is a component used for preventing or reducing contamination on the surface of the optical sheet.
Examples of the antifouling agent include silicone-containing and fluorine-containing antifouling agents, which may be used alone or in combination.

Specific examples of the antifouling agent include a fluorine-containing antifouling agent (trade name: OPTOOL DAC, manufactured by Daikin Industries, Ltd.).
When the antifouling agent is used, the content of the antifouling agent is preferably 0.01 to 1.0% by weight with respect to the total solid content of the second curable resin composition.

(Lubricant)
The easy lubricant is a component used for improving the scratch resistance of the optical sheet surface.
Examples of the lubricant include inorganic fine particles or organic fine particles, which may be used alone or in combination.
Specific examples of the lubricant include silica fine particles (trade name MIBKSIR, manufactured by Catalyst Kasei Kogyo Co., Ltd.).
When the lubricant is used, the content of the lubricant is preferably 0.1 to 3.0% by weight with respect to the solid content of the second curable resin composition.

(Other layers of optical sheet)
As described above, the optical sheet according to the present invention is basically composed of the light-transmitting resin substrate, the first HC layer, and the second HC layer. However, in consideration of the function or application as an optical sheet and without departing from the gist of the present invention, the following one is further provided on the surface of the second HC layer opposite to the first HC layer. Alternatively, two or more layers may be provided. When these other layers are provided, after forming the first and second HC layers, the composition of the other layers may be applied and cured, or the first and second curable layers may be formed. The resin composition may be applied simultaneously by simultaneous multilayer coating and cured to form. When forming by simultaneous multilayer coating, in the composition of other layers, the total solid content with respect to all components of the composition is 30% by mass or more.

  The thicknesses of the other layers vary depending on the lamination conditions including the first and second HC layers, and may be adjusted as appropriate.

(Antistatic layer)
The antistatic layer is made of a cured product of a curable resin composition for an antistatic layer containing an antistatic agent and a curable resin. The thickness of the antistatic layer is preferably about 30 nm to 3 μm.

  As the antistatic agent, the same materials as those mentioned above for the antistatic agent for the HC layer can be used.

  As a curable resin contained in the curable resin composition for an antistatic layer, a known resin can be appropriately selected and used alone or in combination of two or more.

(Anti-fouling layer)
According to the preferable aspect of the present invention, for the purpose of preventing the stain on the outermost surface of the optical sheet, an antifouling layer can be provided on the outermost surface of the optical sheet opposite to the light-transmitting resin substrate. The antifouling layer makes it possible to further improve the antifouling property and scratch resistance of the optical sheet. The antifouling layer comprises a cured product of a curable resin composition for an antifouling layer comprising an antifouling agent and a curable resin composition.

  The antifouling agent and curable resin contained in the curable resin composition for the antifouling layer can be appropriately selected from known antifouling agents and curable resins, and one or more can be used.

(Low refractive index layer)
The low refractive index layer is a layer having a lower refractive index than the layer adjacent to the base material side of the layer, and is made of a cured product of the curable resin composition for the low refractive index layer. In the curable resin composition for a low refractive index layer, a known low refractive index curable resin or fine particles can be appropriately used so that the refractive index is lower than that of the adjacent layer.

FIG. 2 is a diagram schematically illustrating another example of the layer configuration of the optical sheet according to the present invention.
In the optical sheet 1 of FIG. 2, the first HC layer 20, the second HC layer 30, and the antistatic layer 40 are laminated in this order on one surface side of the light transmissive resin base material 10.

(Optical sheet manufacturing method)
The method for producing an optical sheet according to the present invention includes (i) a step of preparing a light-transmitting resin substrate,
(Ii) Reactive functional groups a, b, and c having cross-linking reactivity between the same type and different types of reactive functional groups, respectively, and having an average primary particle size 1 having a reactive functional group a on the particle surface The first reactive silica fine particle of ˜100 nm and the first binder component having the reactive functional group b are included, and the total solid content with respect to all the components of the first curable resin composition is 30% by mass or more. A first curable resin composition and a second binder component having a reactive functional group c, and the total solid content with respect to all components of the second curable resin composition is 30% by mass or more Preparing a second curable resin composition;
(Iii) The first curable resin composition and the second curable resin composition are simultaneously applied to one side of the light transmissive resin base material in this order from the light transmissive base material side, and the coating film The process of
(Iv) including light-irradiating the coating films of the first and second curable resin compositions, curing the coating films, and forming a first hard coat layer and a second hard coat layer. It is characterized by.

  In the method for producing an optical sheet according to the present invention, in each of the first and second curable resin compositions, the total solid content is 30% by mass or more with respect to all the components, whereby the hard coat layer is formed together. Even if it is a composition for forming, the contact part of two compositions mixes moderately, suppressing mixing of the whole composition when apply | coating simultaneously. And since it hardens | cures in a light irradiation process, maintaining the composition of each upper and lower layers in this way, generation | occurrence | production of a coating stripe can be suppressed and the external appearance of an optical sheet can be made favorable. In addition, since the contact portions of the two compositions are mixed appropriately, it is possible to separate functions such as hardness and flexibility of each layer, but no layer interface occurs, and generation of interference fringes on the optical sheet can be suppressed. .

In the case of the conventional method of half-curing and forming a laminate, only a small amount of the composition in the lower layer is irradiated with light once, but curing proceeds only with the components of the lower layer composition on the surface of the lower layer. Resulting in.
On the other hand, in the method for producing an optical sheet according to the present invention, since the half-curing is not performed, the first reactive silica fine particles of the composition on the surface of the coating film of the first curable resin composition as the lower layer or It is presumed that the second binder component of the second curable resin composition in which the first binder component is an upper layer can sufficiently react and the adhesion between the two layers and the hardness of the optical sheet are improved.

  Hereinafter, each step will be described.

  In the step (i), the light-transmitting resin base material described in the optical sheet is prepared.

In the step (ii), the first and second curable resin compositions described in the optical sheet are prepared.
The first curable resin composition is usually prepared by mixing and dispersing a reactive silica fine particle, a first binder component, a polymerization initiator, and the like in a solvent according to a general preparation method. A paint shaker or a bead mill can be used for mixing and dispersing. When the first binder component has fluidity, the first curable resin composition can be applied to the substrate without using a solvent, and therefore a solvent may be used as necessary.
The second curable resin composition can be prepared in the same manner as the first curable resin composition.

  Note that either step (i) or step (ii) may be performed first or simultaneously.

In the step (iii), the coating method is not particularly limited as long as it is a method capable of uniformly coating the first and second curable resin compositions on one side of the light transmissive resin base material. ,
Conventionally known methods can be used. In particular, it is preferable to apply an extrusion type die coater as in Patent Document 2 because it is simple.

  FIG. 3 is a schematic diagram of simultaneous multilayer coating using a two-slot extrusion type die coater. The first curable resin composition 21 and the second curable resin composition 31 are respectively discharged from the slits 61 and 62 of the die coater head 50 of the extrusion type die coater to form a coating film. Of the two slits of the extrusion type die coater, the first curable resin composition 21 is located on the downstream side of the slit 61 located on the upstream side with respect to the traveling direction of the light-transmitting resin base material. Application is performed by discharging the second curable resin composition 31 from 62.

  When other layers are provided on the second HC layer by simultaneous multilayer coating, a slot for discharging the composition of the other layers is further provided on the downstream side with respect to the traveling direction of the light-transmitting resin base material. Other layers can be provided. For example, although not shown, using a three-slot die coat, the first curable resin composition is formed on the light-transmitting resin substrate, the second curable resin composition is further formed thereon, and the antistatic layer is further cured thereon. It is also possible to obtain an optical sheet having a layer structure shown in FIG. 2 by simultaneously applying multiple layers of the functional resin composition and curing it by light irradiation.

  In the present invention, the first and second curable resin compositions at the time of simultaneous multilayer coating on the coater gap 70 and the light transmissive resin base material 10, which are the distance between the die coater head 50 and the light transmissive resin base material 10. It is preferable that the total thickness 80 of the coating film of the object has a relationship of coater gap 70 <(twice the thickness 80). By simultaneously applying multiple layers while maintaining such a relationship, a coating bead formed between the light-transmitting resin substrate 10 and the die coater head 50 is stabilized. In particular, this coating bead tends to become unstable as the layer formed by coating becomes thinner, causing unevenness on the coated surface and deteriorating the appearance, but the relationship between the coater gap 70 and the thickness 80 By keeping this, the coated bead can be stabilized. In addition, a coating bead means the liquid pool produced | generated between a coating device and a base material.

  Moreover, it is preferable that the thickness of the coating film of the 1st and 2nd curable resin composition makes the thickness of the coating film of the 1st curable resin composition relatively thick. By doing in this way, a coating speed can be made quick and an optical sheet can be manufactured with high productivity.

  Moreover, as an application quantity of the 1st and 2nd curable resin composition on a transparent resin base material, it differs with the performance by which the obtained optical sheet is requested | required, and the film thickness after drying is the above-mentioned What is necessary is just to adjust suitably so that it may become the film thickness of the 1st HC layer described in the optical sheet, and the 2nd HC layer.

Moreover, you may dry a coating film between the (iii) process and the (iv) process as needed.
Examples of the drying method include reduced-pressure drying or heat drying, and a method combining these drying methods. Moreover, when drying at normal pressure, it is preferable to dry at 30-110 degreeC. For example, when methyl isobutyl ketone is used as the solvent of the first or second curable resin composition, it is usually room temperature to 80 ° C., preferably 40 ° C. to 70 ° C., for 20 seconds to 3 minutes, The drying step is preferably performed in a time of about 30 seconds to 1 minute.

In the step (iv), ultraviolet rays, visible light, electron beams, ionizing radiation, etc. are mainly used for light irradiation. In the case of ultraviolet curing, ultraviolet rays or the like 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 500 mJ / cm ² as an integrated exposure amount at an ultraviolet wavelength of 365 nm.
In addition to light irradiation, heating may be performed. When heating, the treatment is usually performed at a temperature of 40 ° C to 120 ° C. Moreover, you may react by leaving it to stand for 24 hours or more at room temperature (25 degreeC).

(Formation of other layers)
In the case of forming another layer on the opposite side of the second HC layer from the first HC layer, before curing the coating film of the first and second curable resin compositions, or the above step (iv) After that, the curable resin composition of another layer may be applied, dried, and irradiated with light and / or heated to form another layer.

  Hereinafter, the present invention will be described more specifically with reference to examples. These descriptions do not limit the present invention.

As the silica fine particles (1), Nissan Chemical Industries, Ltd .: IPA-ST (L), average primary particle size 44 nm, colloidal silica, solid content 40% liquid was used.
As reactive irregular shaped silica fine particles (1), JGC Catalysts & Chemicals, Inc .: DP1039 (major axis length of 125 nm in which silica fine particles having an average primary particle size of 25 nm are bonded by an average of inorganic chemical bonds, solid content of 40 mass% The dispersion medium MIBK solvent and the reactive functional group were a methacryloyl group).

As the binder component (1), Nippon Kayaku Co., Ltd .: 6-functional dipentaerythritol hexaacrylate (product name: DPHA) was used.
As the binder component (2), Nippon Kayaku Co., Ltd .: Trifunctional pentaerythritol triacrylate (product name: PET30) was used.
As the binder component (3), Arakawa Chemical Industries, Ltd .: 30 functional or higher polymer acrylate (product name: BS371) having a weight average molecular weight of 40000 was used.

As a polymerization initiator, Ciba Japan Co., Ltd. product: Irgacure 184 was used.
As the triacetyl cellulose base material, Konica 4KY (thickness 40 μm) manufactured by Konica Corporation was used.
A two-slot die coater was used as the simultaneous multilayer coating apparatus.
Abbreviations for each compound are as follows.
DPHA: Dipentaerythritol hexaacrylate PETA: Pentaerythritol triacrylate MIBK: Methyl isobutyl ketone IPA: Isopropanol MEK: Methyl ethyl ketone TAC: Triacetyl cellulose

(Preparation of reactive silica fine particles (1))
The silica fine particles (1) were subjected to solvent substitution from IPA to MIBK using a rotary evaporator to obtain a MIBK dispersion having 40% by weight of silica particles. By adding 5 parts by weight of 3-methacryloxypropylmethyldimethoxysilane to 100 parts by weight of this MIBK dispersion and subjecting to heat treatment at 50 ° C. for 1 hour, surface-treated reactive silica fine particles having an average primary particle size of 44 nm ( A 1 wt% solid MIBK dispersion of 1) was obtained.

(Preparation of curable resin composition)
Components of the composition shown below were blended to prepare curable resin compositions 1-1 to 1-7 and 2-1 to 2-6, respectively.

(Curable resin composition 1-1)
Reactive silica fine particles (1): 30 parts by mass (solid content: 12 parts by mass)
DPHA: 13 parts by mass BS371: 13 parts by mass Irgacure 184: 4 parts by mass MEK: 80 parts by mass

(Curable resin composition 1-2)
Reactive silica fine particles (1): 65 parts by mass (solid content: 26 parts by mass)
DPHA: 13 parts by mass BS371: 13 parts by mass Irgacure 184: 4 parts by mass MEK: 45 parts by mass

(Curable resin composition 1-3)
Reactive silica fine particles (1): 100 parts by mass (solid content: 40 parts by mass)
DPHA: 13 parts by mass BS371: 13 parts by mass Irgacure 184: 4 parts by mass MEK: 10 parts by mass

(Curable resin composition 1-4)
Reactive silica fine particles (1): 78 parts by mass (solid content: 22 parts by mass)
DPHA: 29 parts by mass BS371: 29 parts by mass Irgacure 184: 4 parts by mass

(Curable resin composition 1-5)
Reactive irregularly shaped silica fine particles (1): 100 parts by mass (solid content: 40 parts by mass)
DPHA: 13 parts by mass BS371: 13 parts by mass Irgacure 184: 4 parts by mass MEK: 10 parts by mass

(Curable resin composition 1-6)
Reactive silica fine particles (1): 12.5 parts by mass (solid content: 5 parts by mass)
DPHA: 13 parts by mass BS371: 13 parts by mass Irgacure 184: 4 parts by mass MEK: 97.5 parts by mass

(Curable resin composition 1-7)
Silica fine particles (1): 100 parts by mass (solid content: 40 parts by mass)
DPHA: 13 parts by mass BS371: 13 parts by mass Irgacure 184: 4 parts by mass MEK: 10 parts by mass

(Curable resin composition 2-1)
PET 30:30 parts by mass MEK: 70 parts by mass

(Curable resin composition 2-2)
PET 30: 40 parts by mass MEK: 60 parts by mass

(Curable resin composition 2-3)
PET30: 50 parts by mass MEK: 50 parts by mass

(Curable resin composition 2-4)
DPHA: 50 parts by mass MEK: 50 parts by mass

(Curable resin composition 2-5)
PET30: 60 parts by mass MEK: 40 parts by mass

(Curable resin composition 2-6)
DPHA: 25 parts by mass MEK: 75 parts by mass

(Example 1: Production of optical sheet)
On one side of the TAC substrate, a two-slot die coater is used as the first curable resin composition so that the curable resin composition 1-1 is adjacent to the TAC substrate (becomes a lower layer when cured). In addition, as the second curable resin composition, the curable resin composition 2-1 is applied onto the curable resin composition 1-1 (so as to become an upper layer when cured), and the coating speed is 50 m / min. Were simultaneously applied to form a coating film.
Immediately after drying at 70 ° C. for 1 minute, ultraviolet rays were irradiated at 100 mJ / cm ² by an ultraviolet irradiation device provided in the vicinity of the coating machine, the coating film was cured, and the thickness was 15 μm on each TAC substrate. The first HC layer and the second HC layer were formed in this order.

(Examples 2-6 and Comparative Examples 1-3)
Optical sheets of Examples 2 to 6 and Comparative Examples 1 to 3 were produced in the same manner as Example 1 except that the first and second curable resin compositions were changed to those shown in Table 1, respectively.

(Comparative Example 4)
First, curable resin composition 1-3 is applied to one side of a TAC substrate, dried in a hot oven at a temperature of 70 ° C. for 1 minute, the solvent in the coating film is evaporated, and the integrated light intensity is 50 mJ / cm. ² is then cured, and then the curable resin composition 2-4 is applied to the half-cured first HC layer and dried in a hot oven at a temperature of 70 ° C. for 60 seconds. The coating film of the first and second curable resin compositions is fully cured by evaporating the solvent in the coating film and irradiating ultraviolet rays so that the integrated light quantity becomes 200 mJ / cm ^2. A first HC layer (lower layer) and a second HC layer (upper layer) having a thickness of 15 μm were formed.

(Evaluation of optical sheet)
About the produced optical sheet | seat of Examples 1-6 and Comparative Examples 1-4, an external appearance, interference fringe, pencil hardness, and adhesiveness were evaluated as follows. The results are also shown in Table 1.
Moreover, about Example 4 and Comparative Example 1, the TEM photograph (1000-times multiplication factor) of the film thickness direction cross section of an optical sheet is shown in FIG. 4, FIG. 5, respectively. Moreover, the photograph of the hard-coat layer surface of the optical sheet of the comparative example 1 is shown in FIG.

(Evaluation: Appearance)
Visual observation was performed under reflected light conditions to determine the presence or absence of coating streaks.
○: Appearance is good (no coating streaks)
×: Appearance defect (with coating streaks)

(Evaluation: Interference fringes)
A black tape was attached to the substrate side of the optical sheet and observed under a three-wavelength tube lamp.
○: No interference fringes ×: Interference fringes

(Evaluation: Pencil hardness)
Pencil hardness test: The hardness of the pencil scratch test is as follows. The prepared optical sheet is conditioned at a temperature of 25 ° C. and a relative humidity of 60% for 2 hours, and then the test pencil (hardness 4H) specified by JIS-S-6006 is used. The pencil hardness test (4.9 N load) specified in JIS K5600-5-4 (1999) was performed and measured according to the following criteria.
○: 4H pass (5 lines, no scratch or 1)
X: 4H failure (2 lines or more in 5 lines)

(Evaluation: Adhesion)
A 100 mm grid with a 1 mm square is added to the second HC layer side of the optical sheet, and a continuous peel test is performed 5 times using Nichiban Co., Ltd. industrial 24 mm cello tape (registered trademark). The quantity of eyes was measured, and the adhesion was evaluated by measuring the degree of adhesion based on the following criteria.
Adhesion degree (%) = (number of cells not peeled / total number of cells 100) × 100
○: 90% or more ×: less than 90%

(Summary of results)
From Table 1, the optical sheet of Examples 1-6 obtained the favorable evaluation result.
In the TEM photograph of the cross section in the film thickness direction of the optical sheet of Example 4 shown in FIG. 4, mixing of the entire first and second curable resin compositions is suppressed and included in the first curable resin composition. Silica fine particles obtained by curing reactive silica fine particles are mainly present on the first HC layer (lower layer) side.
However, in Comparative Example 1 in which the solid content mass with respect to all components of the curable resin composition is less than 30% by mass, the first curable resin composition and the second curable resin composition are mixed as a whole. The thickness of the optical sheet of Comparative Example 1 in FIG. 5 is that the deformed silica fine particles of the reactive irregular silica fine particles contained in the first curable resin composition are widely distributed to the second HC layer. It can be seen from the TEM photograph of the cross section in the direction. Moreover, as shown in the photograph of the optical sheet surface of Comparative Example 1 in FIG. 6, coating streaks occurred on the optical sheet surface, resulting in poor appearance.
In Comparative Example 2 in which the silica fine particles contained in the first curable resin composition have no reactive groups, the pencil hardness is reduced due to insufficient strength of the first HC layer due to the absence of crosslinking of the reactive silica fine particles with the binder component. Was not enough.
In Comparative Example 3 where the composition of the lower layer did not contain reactive silica fine particles, the hardness was insufficient because there was no underlayer.
Also, using the same first and second curable resin compositions as in Example 4, instead of simultaneous multilayer coating, half-curing of the first curable resin composition was performed, and then the half-cured coating film and In Comparative Example 4 in which the optical sheet was obtained by combining the coating film of the second curable resin composition to obtain an optical sheet, the upper layer curable resin composition was appropriately coated with a lower layer by curing the lower layer with a half cure. Since it was not mixed with the curable resin composition, a layer interface was present and interference fringes were generated. In addition, since the lower layer was cured by half cure, the optical sheet had insufficient adhesion.

DESCRIPTION OF SYMBOLS 1 Optical sheet 10 Light transmission resin base material 20 1st hard-coat layer 21 1st curable resin composition 30 2nd hard-coat layer 31 2nd curable resin composition 40 Antistatic layer 50 Die coater head 61, 62 Slit 70 Coater gap 80 Total thickness 90 of coating film of first and second curable resin composition Interface 100 between first hard coat layer and triacetyl cellulose substrate 100 Second hard coat layer Air interface 110 coating streaks

Claims (5)

(I) preparing a light transmissive resin base material;
(Ii) Reactive functional groups a, b, and c having cross-linking reactivity between the same type and different types of reactive functional groups, respectively, and having an average primary particle size 1 having a reactive functional group a on the particle surface The first reactive silica fine particle of ˜100 nm and the first binder component having the reactive functional group b are included, and the total solid content with respect to all the components of the first curable resin composition is 30% by mass or more. A first curable resin composition and a second binder component having a reactive functional group c, and the total solid content with respect to all components of the second curable resin composition is 30% by mass or more Preparing a second curable resin composition;
(Iii) The first curable resin composition and the second curable resin composition are simultaneously applied to one side of the light transmissive resin base material in this order from the light transmissive base material side, and the coating film The process of
(Iv) including light-irradiating the coating films of the first and second curable resin compositions, curing the coating films, and forming a first hard coat layer and a second hard coat layer. A method for producing an optical sheet, comprising:   The first curable resin composition and the second curable resin composition each further contain a solvent, and the total solid content with respect to all components of the first curable resin composition is 40 to 60% by mass. And the sum total of solid content with respect to all the components of said 2nd curable resin composition is 40-60 mass%, The manufacturing method of the optical sheet of Claim 1 characterized by the above-mentioned. An optical sheet in which the first hard coat layer and the second hard coat layer are provided in this order from the light transmissive resin base material side on one surface side of the light transmissive resin base material,
The light-transmitting resin base material, the reactive functional groups a, b, and c having cross-linking reactivity between the same and different reactive functional groups, respectively, and having the reactive functional group a on the particle surface A first reactive silica fine particle having a primary particle size of 1 to 100 nm and a first binder component having a reactive functional group b, the total solid content of all the components of the first curable resin composition is 30 The first curable resin composition having a mass% or more and the second binder component having the reactive functional group c, and the total solid content with respect to all the components of the second curable resin composition is 30 mass. % Of the second curable resin composition is prepared,
The first curable resin composition and the second curable resin composition are simultaneously applied to one surface side of the light transmissive resin base material in order from the light transmissive resin base material side to form a coating film,
It is obtained by irradiating the coating film of the first and second curable resin compositions with light, curing the coating film, and forming the first hard coat layer and the second hard coat layer. An optical sheet characterized in that there is no layer interface between the hard coat layer and the second hard coat layer.   The first curable resin composition and the second curable resin composition each further contain a solvent, and the total solid content with respect to all components of the first curable resin composition is 40 to 60% by mass. The total of the solid content with respect to all the components of said 2nd curable resin composition is 40-60 mass%, The optical sheet of Claim 3 characterized by the above-mentioned.   5. The optical sheet according to claim 3, wherein the hardness of a pencil hardness test (4.9 N load) specified in JIS K5600-5-4 (1999) is 4H or more.