JP2008107792A - Antireflection laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antireflection laminate having a refractive layer which is excellent in resistance to scuffing, has a refractive index of 1.45 or less and secures low reflectivity while being provided with hollow particles and solid particles with respect to the antireflection laminate principally used for displays of LCD, PDP or the like. <P>SOLUTION: In the antireflection laminate having the refractive layer with a refractive index of 1.45 or less, a refractive layer forming composition comprises: an ionizing radiation-curable resin; the cross-linking reactive hollow particles each of which comprises the porous or hollow interior surrounded by an outer-shell layer and the surface modified by cross-linking forming groups; and the cross-linking reactive solid particles each of which comprises the interior being neither porous nor hollow and the surface modified by cross-linking forming groups, wherein the cross-linking reactive groups comprise ionizing radiation-curable groups and, in both of the hollow particles and solid particles, have the same structure or extremely analogous structure and the refractive layer is obtained by irradiating the refractive layer forming composition with ionizing-radiation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an antireflection laminate that is installed in front of a display (image display device) such as an LCD.

  The display surface of an image display device such as a liquid crystal display (LCD), a cathode ray tube display device (CRT), or a plasma display panel (PDP) reduces the reflection caused by light rays emitted from an external light source such as a fluorescent lamp, and its visibility. Is required. For this reason, conventionally, an antireflection film utilizing the phenomenon that the reflectivity is reduced by covering the surface of a transparent object with a transparent film (low refractive index layer) having a low refractive index is provided on the display surface of the image display device. By providing, it has been studied to improve the visibility by reducing the reflectivity of the display surface.

There are various methods for reducing the refractive index, but one method includes reducing the refractive index of the entire film by containing air having a refractive index of 1 inside the film.
As such a refractive index layer containing air inside the film, for example, in Patent Document 1, an ionizing radiation curable resin composition is provided for the purpose of providing an antireflection film having a low refractive index and excellent mechanical strength. And at least a part of the surface of the silica fine particle is treated with a silane coupling agent having an outer shell layer and having a porous or hollow interior and having an ionizing radiation curable group. An antireflection film having a low refractive index layer is disclosed.

Patent Document 2 discloses a compound having at least two (meth) acryloyloxy groups in the molecule or an oligomer thereof and porous fine particles for the purpose of improving the antireflection performance of the low refractive index layer. Techniques using cured coatings from containing compositions are disclosed.
However, since the porous fine particles are inorganic, the affinity with the organic binder component is inferior unless surface treatment such as a silane coupling agent is performed. Therefore, the porous fine particles are aggregated in the cured film and are likely to be unevenly distributed. As a result, the in-plane refractive index differs depending on the location, or a film in which a transparent part and an opaque part are mixed is obtained. Such an antireflection film having a non-uniform film structure has a problem of poor scratch resistance such as steel wool resistance.

  Further, Patent Document 3 discloses porous fine particles, non-porous inorganic compound fine particles, a curable compound, and an antireflective layer, with the expectation of improving the film hardness of the refractive index layer and imparting antistatic functions to the layer. A technique using a cured coating from a composition containing a binder component selected from resins as a refractive index layer is disclosed.

  Solid particles are not porous, hollow, or dense, so the strength of the particles themselves is higher than that of hollow particles. Therefore, by containing solid particles in the refractive index layer, an improvement in strength against the pressing force in the film thickness direction (direction perpendicular to the film plane) of the refractive index layer can be expected.

JP 2005-99778 A JP 2003-262703 A JP 2003-266606 A

  However, according to the study of the present inventor, it has been found that if the method described in Patent Document 3 is adopted, the hardness of the refractive index layer may be reduced contrary to the above expectation. Specifically, it was found that when inorganic compound particles (solid particles) that are not porous are included for the purpose of improving the hardness, the scratch resistance of the refractive index layer is deteriorated and the surface hardness is rather lowered.

  Solid particles have a higher refractive index than hollow particles because they are dense inside and do not contain air. For this reason, when a large amount of solid particles are added to the refractive index layer for the purpose of improving the film strength, the refractive index of the layer is increased, and there is a problem that the antireflection performance of the antireflection film made of the layer is lowered.

  The present invention has been made to solve the above-mentioned problems, and has excellent scratch resistance and a refractive index of 1.45 or less while having hollow particles and solid particles to ensure low reflectivity. An object is to provide an antireflection laminate having a refractive index layer.

The antireflection laminate according to the present invention is an antireflection laminate having a refractive index layer having a refractive index of 1.45 or less,
The refractive index layer is a cured product obtained by irradiating a composition for forming a refractive index layer with ionizing radiation,
The refractive index layer forming composition comprises an ionizing radiation curable resin,
Cross-linking reactive hollow particles whose interior surrounded by the outer shell layer is porous or hollow and whose surface is modified with a cross-linking group;
Containing solid cross-linking reactive particles whose interior is neither porous nor hollow, and whose surface is modified with a cross-linking group;
The crosslink forming group on the surface of the hollow particle and the crosslink forming group on the surface of the solid particle are composed of a bonding group to the particle surface, a spacer part, and an ionizing radiation curable group, and have the same structure or structural differences. Even if there is, the ionizing radiation curable group has a common skeleton and is within a range in which the presence or absence of one hydrocarbon group having 1 to 3 carbon atoms is different, and is bonded to the particle surface. For the group, the skeleton is common, and the presence or absence of one hydrocarbon group having 1 to 3 carbon atoms is different. For the spacer portion, the skeleton is common, and It is within the range where only one hydrocarbon group having 1 to 3 carbon atoms or one functional group having 1 to 3 functional atoms containing different atoms and excluding hydrogen is different, or carbon of the skeleton Range in which the chain length only differs by 1 to 2 carbon atoms Characterized in that it is a bridging form having a similar structure is.

  The hollow particles contain air inside the particles, and since the refractive index of air is 1, the refractive index is lower than that of the ionizing radiation curable resin or solid particles in the refractive index layer. For this reason, the refractive index layer containing the hollow particles can be lowered in refractive index, and the reflectivity of the antireflection laminate according to the present invention can be reduced and the visibility can be improved.

  Further, since the solid particles do not have voids inside the particles, the solid particles are less likely to be crushed by pressure (external pressure) applied to the particles from the outside, and are excellent in pressure resistance, compared to hollow particles. Therefore, it becomes easy to improve the scratch resistance of the refractive index layer containing the solid particles. In the present specification, the void means a cavity containing air or a void contained in a porous structure.

  Furthermore, the hollow particles and the solid particles according to the present invention are modified on the surface of the particles with a cross-linking group having the same structure or having a large number of common parts of the primary structure. Since the cross-linking group has cross-linking reactivity, a cross-linking bond can be formed between the hollow particles, the solid particles, and the ionizing radiation curable resin. Such cross-linking bonds strengthen the bond between the particles and the resin compared to conventional antireflection layers. In addition, since the common part of the cross-linking group is very large, the affinity between the hollow particles and the solid particles is higher than before, and the aggregation between the hollow particles and the aggregation between the solid particles are It is difficult to occur, and the hollow particles and the solid particles are uniformly and densely packed in the refractive index layer. Thereby, the refractive index layer according to the present invention has a smooth surface, and can improve the scratch resistance (steel wool resistance) against scratching of the surface of the layer.

  In the antireflection laminate according to the present invention, the hollow particles and the solid particles are preferably inorganic particles. Since the inorganic particles have high hardness, when the refractive index layer is formed by mixing with the ionizing radiation curable resin, the scratch resistance of the layer can be improved.

  In the antireflection laminate according to the present invention, the hollow particles and the solid particles are at least one selected from the group consisting of metal oxides, metal nitrides, metal sulfides, and metal halides. It is preferable because particles having high strength and good pressure resistance can be obtained stably.

  In the antireflection laminate according to the present invention, the modification of the crosslink forming group on the surface of the hollow particle and the solid particle is composed of a binding group, a spacer part and an ionizing radiation curable group on the particle surface, and has the same structure Even if there are structural differences, the ionizing radiation curable groups have the same skeleton and differ only in the presence or absence of one hydrocarbon group having 1 to 3 carbon atoms. As for the bonding group to the particle surface, the group other than the spacer portion bonded to the bonding group is the presence or absence of one hydrocarbon group having 1 to 3 carbon atoms. Are different from each other, and the spacer portion has a common skeleton and has 1 to 3 hydrocarbon atoms having 1 to 3 carbon atoms, or 1 to 1 constituent atoms including heteroatoms and excluding hydrogen. The presence or absence of one functional group of 3 is different Or in the range of, or preferably for the carbon chain length of the backbone is carried out using a coupling agent having a similar structure are within the scope of different only 1-2 min carbon atoms is excellent in productivity.

  In the antireflection laminate according to the present invention, the coupling agent is 1 part by weight or more, 200 parts by weight or less, and 100 parts by weight of the solid particles with respect to 100 parts by weight of the hollow particles. The coupling agent is preferably modified using 1 part by weight or more and 200 parts by weight or less. By making the use amount of the coupling agent 1 part by weight or more, the affinity of the hollow particles and the solid particles for the ionizing radiation curable resin mainly composed of organic components is improved, and the coating liquid and the refractive index are improved. Uniform dispersion of the hollow particles and the solid particles in the layer is stably performed, and the amount of the coupling agent used is 50 parts by weight or less, thereby treating the hollow particles and the solid particles. Generation | occurrence | production of the free coupling agent which was not used can be suppressed favorably, and the softness | flexibility of the said refractive index layer can be ensured.

In one form of the antireflection laminate according to the present invention, the average particle diameter A of the solid particles and the average particle diameter B of the hollow particles are as follows:
10 nm ≦ A ≦ 40 nm;
30 nm ≦ B ≦ 60 nm; and A ≦ B,
It is preferable to have
In the laminate, the refractive index layer preferably contains 5 to 50 parts by weight of the hollow particles with respect to 100 parts by weight of the solid particles. By adopting such a range, the solid particles enter the gaps between the hollow particles in the refractive index layer, and more densely packed, thereby improving the scratch resistance of the surface of the layer, particularly steel wool resistance. The effect is particularly high.
In the present invention, the average particle diameter means a 50% particle diameter (d50 median diameter) when particles in a solution are measured by a dynamic light scattering method and the particle diameter distribution is expressed by a cumulative distribution. The average particle size can be measured using a Microtrac particle size analyzer manufactured by Nikkiso Co., Ltd. In addition, the average particle diameter in the film is measured using a transmission electron microscope (TEM; Transmission Electron Microscope). Specifically, the particles are observed at a magnification of 500 to 2,000,000, and the average value of 100 observed particles is defined as the average particle diameter.

In another form of the antireflection laminate according to the present invention, the average particle diameter A of the solid particles and the average particle diameter B of the hollow particles are as follows:
30 nm <A ≦ 100 nm;
30 nm ≦ B ≦ 60 nm; and A> B,
It is preferable to have
In the laminate, the refractive index layer preferably contains 5 to 50 parts by weight of the hollow particles with respect to 100 parts by weight of the solid particles. By making such a range, in the refractive index layer, the solid particles having a large volume increase, a gap between the solid particles and the hollow particles is generated during film formation, and air exists in the gap. The effect of reducing the reflectance of the refractive index layer is particularly high.

  In the antireflection laminate according to the present invention, at least a part of the ionizing radiation curable resin has at least one hydrogen bond forming group and three or more ionizing radiation curable groups in one molecule. Preferably formed from a compound. When the ionizing radiation curable resin has a hydrogen bond-forming group as described above, it is cured by heating to cause a polymerization reaction or a crosslinking reaction between the same functional groups or between different functional groups to form a coating film. can do. In addition, when the ionizing radiation curable resin has an ionizing radiation curable group as described above, the curable group is cured by proceeding a polymerization reaction or a crosslinking reaction by irradiation with ionizing radiation to form a coating film. be able to

  In the antireflection laminate according to the present invention, the ionizing radiation curable group is preferably an acryloyl group and / or a methacryloyl group. The acryloyl group and methacryloyl group are excellent in productivity, and the mechanical strength in the refractive index layer after curing can be easily controlled.

  In the antireflection laminate according to the present invention, the ionizing radiation curable resin, the hollow particles, and the solid particles are covalently bonded via the ionizing radiation curable group. It is preferable because the scratch resistance can be improved.

  In the antireflection laminate according to the present invention, the film thickness of the refractive index layer is preferably 0.05 μm or more and 0.15 μm or less because the refractive index layer can provide a sufficient antireflection effect.

  In the antireflection laminate according to the present invention, it is preferable that a refractive index of the solid particles is smaller than a refractive index of the ionizing radiation curable resin. If the refractive index of the solid particles is made smaller than that of the ionizing radiation curable resin, the refractive index of the refractive index layer can be further reduced.

  In the antireflection laminate according to the present invention, the refractive index layer is provided directly or via another layer as a low refractive index layer having the lowest refractive index on one surface side of the light-transmitting substrate. Is preferred.

  In the antireflection laminate according to the present invention, the other layer is preferably a hard coat layer.

  In the antireflection laminate according to the present invention, since the hollow particles and solid particles are uniformly and densely packed in the refractive index layer, the layer strength is improved and the scratch resistance is excellent.

The antireflection laminate according to the present invention is an antireflection laminate having a refractive index layer having a refractive index of 1.45 or less,
The refractive index layer is a cured product obtained by irradiating a composition for forming a refractive index layer with ionizing radiation,
The refractive index layer forming composition comprises an ionizing radiation curable resin,
Cross-linking reactive hollow particles whose interior surrounded by the outer shell layer is porous or hollow and whose surface is modified with a cross-linking group;
Containing solid cross-linking reactive particles whose interior is neither porous nor hollow, and whose surface is modified with a cross-linking group;
The crosslink forming group on the surface of the hollow particle and the crosslink forming group on the surface of the solid particle are composed of a bonding group to the particle surface, a spacer part, and an ionizing radiation curable group, and have the same structure or structural differences. Even if there is, the ionizing radiation curable group has a common skeleton and is within a range in which the presence or absence of one hydrocarbon group having 1 to 3 carbon atoms is different, and is bonded to the particle surface. For the group, the skeleton is common, and the presence or absence of one hydrocarbon group having 1 to 3 carbon atoms is different. For the spacer portion, the skeleton is common, and It is within the range where only one hydrocarbon group having 1 to 3 carbon atoms or one functional group having 1 to 3 functional atoms containing different atoms and excluding hydrogen is different, or carbon of the skeleton Range in which the chain length only differs by 1 to 2 carbon atoms Characterized in that it is a bridging form having a similar structure is.

  The hollow particles contain air having a refractive index of 1 inside the particles, and have a refractive index lower than that of the ionizing radiation curable resin or solid particles in the refractive index layer. For this reason, the refractive index layer containing the hollow particles can be lowered in refractive index, and the reflectivity of the antireflection laminate according to the present invention can be reduced and the visibility can be improved. In addition, the measurement of a refractive index is not specifically limited, A conventionally well-known method can be used. For example, a method of calculating from a reflectance curve measured with a spectrophotometer using a simulation or a method of measuring using an ellipsometer can be given.

  Further, since the solid particles do not have voids inside the particles, the solid particles are less likely to be crushed by pressure (external pressure) applied to the particles from the outside, and are excellent in pressure resistance, compared to hollow particles. Therefore, it becomes easy to improve the scratch resistance of the refractive index layer containing the solid particles.

Furthermore, the hollow particles and the solid particles according to the present invention are modified on the surface of the particles with a cross-linking group having the same structure or having a large number of common parts of the primary structure. Since the cross-linking group has cross-linking reactivity, a cross-linking bond can be formed between the hollow particles, the solid particles, and the ionizing radiation curable resin. Such cross-linking bonds strengthen the bond between the particles and the resin compared to conventional antireflection layers. In addition, since the common part of the cross-linking group is very large, the affinity between the hollow particles and the solid particles is higher than before, and the aggregation between the hollow particles and the aggregation between the solid particles are It is difficult to occur, and the hollow particles and the solid particles are uniformly and densely packed in the refractive index layer. Thereby, the refractive index layer according to the present invention has a smooth surface, and can improve the scratch resistance (steel wool resistance) against scratching of the surface of the layer.

  Hereinafter, a composition for forming a refractive index layer, which is a component for forming a refractive index layer according to the present invention, and an antireflection laminate using the composition will be described in order.

<1. Refractive index layer forming composition>
The composition for forming a refractive index layer according to the present invention includes, as an essential component, a cross-linking reactive hollow particle whose surface is modified with a cross-linking group, and a cross-linking reactivity whose surface is modified with a cross-linking group. Includes real particles and ionizing radiation curable resin. Hereinafter, the hollow particles, the solid particles, the ionizing radiation curable resin, and other components used as necessary, which are essential components of the composition for forming a refractive index layer, will be described.

<1-1-1. Hollow particles>
The hollow particle according to the present invention refers to a particle having an outer shell layer, and the inside surrounded by the outer shell layer is a porous structure or a cavity. The porous structure and the cavity contain air (refractive index: 1), and the refractive index of the layer can be reduced by containing the hollow particles in the refractive index layer.

  As the material for the hollow particles according to the present invention, inorganic and organic materials can be used. In consideration of productivity and strength, an inorganic material is preferable. In this case, the outer shell layer is formed of an inorganic material.

  When the hollow particles are formed of an inorganic material, the material of the hollow particles is preferably at least one selected from the group consisting of metal oxides, metal nitrides, metal sulfides, and metal halides. If hollow particles are used as the material, particles having a high strength outer shell and are not easily crushed by external pressure can be obtained. More preferably, the hollow particle material is formed of a metal oxide or a metal halide, and particularly preferably formed of a metal oxide or a metal fluoride. When these materials are used, hollow particles having higher strength and lower refractive index can be obtained.

  Here, as a metal element used for a metal oxide etc., Na, K, Mg, Ca, Ba, Al, Si, and B are preferable, and Mg, Ca, Al, and Si are more preferable. By using such a metal element, hollow particles that have a low refractive index and are easier to manufacture than other elements can be obtained. The above metal elements may be used alone or in combination of two or more.

  Specific examples of the organic fine particles having voids preferably include hollow polymer fine particles prepared by using the technique disclosed in JP-A-2002-80503.

In the present invention, when the hollow particles are formed of a metal oxide, it is particularly preferable to use hollow particles made of silica (silicon dioxide: SiO ₂ ) in consideration of the refractive index and productivity of the material. The hollow silica particles have fine voids inside, and air having a refractive index of 1 is contained inside the particles. Therefore, the refractive index of the particle itself is lower than that of the solid particle and the ionizing radiation curable resin, and the refractive index of the refractive index layer containing the particle can be reduced. That is, the hollow silica particles having voids have a refractive index as low as 1.20 to 1.45 compared to silica particles having no gas inside (refractive index n = 1.46 or so), and the refractive index of the refractive index layer The rate can be 1.45 or less.

<1-1-2. Method for producing hollow particles>
The type of the hollow silica particles is not particularly limited as long as the refractive index is 1.44 or less. Examples of such hollow silica particles include composite oxide sols or hollow silica fine particles disclosed in JP-A Nos. 7-133105 and 2001-233611. Specifically, such hollow silica fine particles can be produced by the following first to third steps, and the following fourth step may be further performed.

That is, as the first step, an alkali aqueous solution of a silica raw material and an inorganic oxide raw material other than silica is separately prepared in advance, or an aqueous solution in which both raw materials are mixed is prepared. Next, according to the composite ratio of the target composite oxide, the obtained aqueous solution is gradually added to an alkaline aqueous solution having a pH of 10 or more while stirring. In this way, colloidal particles made of the complex oxide are obtained. Instead of the first step, a dispersion containing seed particles in advance can be used as a starting material.
Here, the seed particle is a particle that can be used to form a cavity or a porous structure in the preparation of the hollow particle, and the particle grows using the particle as a seed to become a core particle. In the subsequent second step, all or part of the core particles are removed to form the cavity or the porous structure. By using seed particles, it is easy to control the particle size of the grown particles, and core particles having a uniform particle size can be obtained.

  Next, as a second step, at least a part of elements other than silicon and oxygen is selectively removed from the colloidal particles made of the composite oxide obtained in the above step. Specifically, the elements in the composite oxide are dissolved and removed using a mineral acid or an organic acid, or are contacted with a cation exchange resin and removed by ion exchange. Thus, composite oxide colloidal particles from which some elements have been removed are obtained.

  Subsequently, as a third step, by adding a hydrolyzable organosilicon compound or silicic acid solution to the composite oxide colloidal particles from which some elements obtained in the above step have been removed, The surface is coated with a hydrolyzable organosilicon compound or a polymer such as silicic acid solution. In this manner, silica fine particles that are the composite oxide sol described in the above publication can be obtained.

Examples of hydrolyzable organosilicon compounds include, for example, the general formula R _n Si (OR ′) _4-n (where R, R ′ are hydrocarbon groups such as alkyl groups, aryl groups, vinyl groups, acrylic groups, Alkoxysilanes represented by n = 0, 1, 2 or 3) can be used. In particular, tetraalkoxysilanes such as teramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane are preferably used.

  As an addition method, for example, a solution obtained by adding a small amount of alkali or acid as a catalyst to a mixed solution of these alkoxysilane, pure water, and alcohol is added to the colloidal particles obtained in the second step, and alkoxysilane is added. The silicic acid polymer produced by hydrolyzing is deposited on the surface of the colloidal particles. At this time, alkoxysilane, alcohol, and catalyst may be simultaneously added to the colloidal particles. As the alkali catalyst, ammonia, an alkali metal hydroxide, or an amine can be used. As the acid catalyst, various inorganic acids and organic acids can be used.

  When the dispersion medium of the colloidal particles is water alone or the ratio of water to the organic solvent is high, a coating treatment with a silicic acid solution is also possible. The silicic acid solution is an aqueous solution of a low polymer of silicic acid obtained by dealkalizing an aqueous solution of alkali metal silicate such as water glass by ion exchange treatment. When a silicic acid solution is used, a predetermined amount of the silicic acid solution is added to the colloidal particles, and at the same time an alkali is added to polymerize and gel the silicic acid solution, thereby depositing the silicic acid polymer on the surface of the colloidal particles. In addition, it is also possible to perform a coating process by using the silicic acid solution and the alkoxysilane together. The amount of the organosilicon compound or silicic acid solution added is such that each polymer can sufficiently cover the surface of the colloidal particles.

  Furthermore, it is preferable to hydrothermally treat the silica particles obtained in the third step in the range of 50 to 300 ° C. as the fourth step. When the hydrothermal treatment temperature is set to 50 ° C. or higher, the content of alkali metal oxide and / or ammonia in the finally obtained silica particles or silica particle dispersion is effectively reduced, and the coating solution is stably stored. Property and film strength are improved. On the other hand, when the hydrothermal treatment temperature is 300 ° C. or lower, the storage stability of the coating liquid and the coating strength are improved, and aggregation of silica particles is suppressed.

  The silica particles obtained up to the third step tend to have various low-molecular compounds as ionic impurities on the particle surface. The ionic impurities are attributed to those contained in the raw material of the particles, additives added in the manufacturing process, and the like. Therefore, in the fourth step, by removing the ionic impurities by hydrothermal treatment, the amount of impurities on the surface of the silica particles can be easily reduced to a predetermined amount or less.

Specifically, the content of the alkali metal oxide in the silica particles is preferably 10 ppm or less, more preferably 5 ppm or less, and particularly preferably 2 ppm or less. Particularly, when the content of the alkali metal oxide is 5 ppm or less, the stability of the coating solution containing silica particles is improved. That is, even when the coating solution is stored for a long period of time, an increase in the viscosity of the coating solution is suppressed, and excellent storage stability can be realized. In addition, by setting the content of the alkali metal oxide in the above range, it is speculated that the reaction between the surface of the silica particles and a compound for introducing a cross-linking group such as a silane coupling agent occurs more strongly. In addition, the strength of the refractive index layer is improved (the silane coupling agent will be described later). Moreover, film forming property and the intensity | strength of the film | membrane obtained can be improved by content of an alkali metal oxide being 10 ppm or less. The content of alkali metal oxides, M 2 _{O (M} represents an alkali metal element) refers to the content of the by general AAS or ICP MS measurements can determine the content.

Further, the content of ammonia (including ammonium ions) in the silica particles is preferably 2000 ppm or less, more preferably 1500 ppm or less, and particularly preferably 1000 ppm or less. In particular, when the ammonia content is 1500 ppm or less, the stability of the coating liquid containing silica particles is improved. That is, even when the coating liquid is stored for a long period of time, an increase in the viscosity of the coating liquid is suppressed, and excellent storage stability can be realized. In addition, by setting the ammonia content within the above range, it is speculated that the reaction between the surface of the silica particles and a compound for introducing a cross-linking group such as a silane coupling agent will occur more strongly, resulting in refraction. The strength of the rate layer is also improved. Further, when the ammonia content is 2000 ppm or less, the film forming property and the strength of the obtained film can be improved in the same manner as described above. The content of ammonia (including ammonium ions) in the silica particles means the content as NH ₃ , and the content can be measured by a general chemical analysis method.

  In order to make the content of the impurity compound in the silica particles in the above range, the fourth step (hydrothermal treatment step) may be repeated a plurality of times. By repeating the hydrothermal treatment, the content of alkali metal oxide and / or ammonia (including ammonium ions) in the obtained silica-based particles can be reduced.

<1-2-1. Solid particles>
The solid particle according to the present invention refers to a particle whose inside is neither porous nor hollow. Since it does not have voids, it is less likely to be crushed by pressure (external pressure) applied to the particles from the outside, and it has excellent pressure resistance compared to hollow particles. Therefore, it becomes easy to improve the scratch resistance of the refractive index layer containing the solid particles.

  As the material for the solid particles according to the present invention, inorganic or organic materials can be used. In consideration of improvement in strength against the pressing force of the refractive index layer, it is preferable to use an inorganic material.

  When the solid particles are formed of an inorganic material, the material of the solid particles is preferably at least one selected from the group consisting of metal oxides, metal nitrides, metal sulfides, and metal halides. If solid particles are used as the material, high-strength particles can be obtained stably. More preferably, the solid particle material is a metal oxide or a metal halide, and even more preferably a metal oxide or a metal fluoride. When these materials are used, the refractive index is low and the performance as an antireflection layer tends to be good.

  The metal element used for the metal oxide or the like is preferably Na, K, Mg, Ca, Ba, Al, Si, or B, and more preferably Mg, Ca, Al, or Si. By using such a metal element, the strength can be increased and the refractive index can be decreased. The metal elements may be used alone or in combination of two or more.

In the present invention, in order to further reduce the refractive index of the refractive index layer, the refractive index of the solid particles is preferably smaller than the refractive index of the ionizing radiation curable resin. The refractive index of silica (SiO ₂ ) is 1.42 to 1.46, which is lower than the refractive index of 1.49 to 1.55 of an acrylic resin preferably used as an ionizing radiation curable resin. For this reason, it is particularly preferable to use silica (SiO ₂ ) as the solid particle material.

<1-2-2. Production method of solid particles>
The solid particles can be produced by a conventionally known production method. As such a method, for example, a sol-gel method that is a chemical method, a gas evaporation method that is a physical method, and the like can be given.

<1-3. Relationship between hollow particles and solid particles>
In one form of the antireflection laminate according to the present invention, the average particle diameter A of the solid particles and the average particle diameter B of the hollow particles are as follows:
10 nm ≦ A ≦ 40 nm;
30 nm ≦ B ≦ 60 nm; and A ≦ B,
It is preferable that A + 10 ≦ B.
In the antireflection laminate according to the present invention, the refractive index layer preferably contains 5 to 50 parts by weight of the hollow particles with respect to 100 parts by weight of the solid particles. By setting it as the above range, the solid particles enter the gaps between the hollow particles in the refractive index layer and more closely fill them, thereby improving the scratch resistance of the surface of the layer, in particular, the steel wool resistance. The effect is particularly high.

In another form of the antireflection laminate according to the present invention, the average particle size A of the solid particles and the average particle size B of the hollow particles have the following relationship:
30 nm <A ≦ 100 nm;
30 nm ≦ B ≦ 60 nm; and A> B,
It is preferable that A ≧ B + 10.
In the antireflection laminate according to the present invention, the refractive index layer preferably contains 5 to 50 parts by weight of the hollow particles with respect to 100 parts by weight of the solid particles. By setting it as the said range, the volume occupation rate of the said solid particle in the said refractive index layer becomes large, and the effect of reducing the reflectance of the said refractive index layer is especially high.
In the case of hollow particles and solid particles by conventional surface treatment, when the solid particles are larger than the hollow particles, the affinity between the different types of particles is low and aggregation of the same kind of particles is likely to occur, resulting in an increase in haze. It was. On the other hand, by using the surface treatment of the present invention for hollow particles and solid particles, even when the solid particles are larger than the hollow particles, the affinity between different types of particles is high and uniform in the layer. And it is easy to pack densely. Further, since the particles having a large particle size are mixed with each other, a gap between the filled particles is increased, and air is present. Therefore, by having the above range, the low refractive index layer of the present invention has a particularly high effect of reducing the reflectance.

  The thickness of the outer shell layer of the hollow particles according to the present invention is usually 1 nm or more, preferably 2 nm or more. When the thickness of the outer shell layer is in the above range, the particles can be easily coated and other components such as ionizing radiation curable resin are less likely to enter the particles. As a result, the decrease in internal cavities and porous structure is reduced, and the effect of low refractive index is easily obtained. On the other hand, the thickness of the outer shell layer of the hollow particles is usually 30 nm or less, preferably 20 nm or less. When the thickness of the outer shell layer is within the above range, the effect of a low refractive index can be obtained without reducing the porosity of the particles.

<1-4. Crosslink forming group>
The hollow particles and the solid particles according to the present invention have the same structure on the particle surface, or even if there are structural differences, the ionizing radiation curable groups have a common skeleton and carbon. The number of atoms of the hydrocarbon group having 1 to 3 atoms is within a range that is different, and the bonding group to the particle surface has a common skeleton and a group other than the spacer unit bonded to the bonding group. Is within a range in which the presence or absence of one hydrocarbon group having 1 to 3 carbon atoms is different, and the spacer portion has a common skeleton and has 1 to 3 carbon atoms. Within a range in which the presence or absence of one group or one functional group containing 1 to 3 heterogeneous atoms and excluding hydrogen is different, or the skeleton has a carbon chain length of 1 to 2 carbon atoms Modified with cross-linking groups that have similar structures that are only within different ranges To have. As a compound used as the said bridge | crosslinking formation group, a coupling agent is mentioned, for example, As a coupling agent, a silane coupling agent is preferable. The silyloxy moiety of the silane coupling agent can become the bonding group by hydrolysis.

  Examples of the silane coupling agent preferably used in the present invention include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, Examples include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 2-methacryloxypropyltrimethoxysilane, and 2-methacryloxypropyltriethoxysilane.

<1-4-1. Bonding group>
The binding group is a site where the cross-linking group is bonded to the hollow particles and the solid particles, and means a group capable of forming a covalent bond with the hollow particles and the solid particles. As a specific example, when 3-methacryloxypropyltrimethoxysilane which is one of the silane coupling agents is taken as an example, in the following chemical formula (1), 3-methacryloxypropyltrimethoxysilane which is the silane coupling agent 1 The —Si (OCH ₃ ) ₃ moiety 2 can be hydrolyzed to change to the bonding group —Si (OH) ₃ .

<1-4-2. Spacer>
The spacer portion according to the present invention is a site that connects the bonding group and an ionizing radiation curable group, which will be described later, in the crosslinking group, and has an affinity for the ionizing radiation curable resin made of an organic component to the crosslinking group. It also has a function to give. As a specific example, when 3-methacryloxypropyltrimethoxysilane, which is one of the silane coupling agents, is taken as an example, in the above chemical formula (1), -methacryloxypropyltrimethoxysilane— The COO (CH ₂ ) ₃ portion 3 corresponds to the spacer portion.
<1-4-3. Ionizing radiation curable groups>
The ionizing radiation curable group according to the present invention is a functional group that can be cured by a polymerization reaction or a crosslinking reaction by irradiation with an ionizing radiation curable resin, which is an essential component for forming a refractive layer, and ionizing radiation. The curable group has a function of improving the strength of the refractive index layer by polymerizing with the resin.

  As such ionizing radiation curable groups, for example, the reaction proceeds by a polymerization reaction such as photo radical polymerization, photo cation polymerization, photo anion polymerization, or addition reaction or condensation polymerization that proceeds through photodimerization. To do. In particular, a group having an ethylenically unsaturated bond such as a (meth) acryloyl group, a vinyl group, or an allyl group is directly or indirectly subjected to the action of an initiator by irradiation with ionizing radiation such as an ultraviolet ray or an electron beam. Since a radical polymerization reaction can be caused, handling including a photocuring process is relatively easy. Among these, the (meth) acryloyl group is preferred as the ionizing radiation curable group because of excellent productivity and easy control of the mechanical strength in the refractive index layer after curing. In the present invention, (meth) acryloyl means acryloyl and / or methacryloyl.

As a specific example, when 3-methacryloxypropyltrimethoxysilane, which is one of the silane coupling agents, is taken as an example, in the chemical formula (1), CH of 3-methacryloxypropyltrimethoxysilane, which is the silane coupling agent 1, is used. ₂ = C (CH ₃ ) -part 4 corresponds to an ionizing radiation curable group.

FIGS. 1 and 2 are diagrams schematically showing the modification mechanism of the particle surface, taking as an example the case of using a silane coupling agent which is a kind of a compound that becomes a cross-linking group.
In FIG. 1, as a first step, the silane coupling agent 101 generates a crosslink forming group 102 having a bonding group by a hydrolysis reaction 110.
Subsequently, as a second step, the cross-linking group 102 forms a cross-linking group 104 that is hydrogen-bonded to the polar group on the particle surface by the hydrogen bond 111 to the polar group 103 on the particle surface.
Further, as the third step, the hydrogen-bonded cross-linking group 104 is heated and dehydrated 112 to produce the target particle 105 whose surface is modified with the cross-linking group.

In FIG. 2, as a first step, the silane coupling agent 101 generates a cross-linking group 102 having a bonding group by a hydrolysis reaction 110,
Subsequently, as a second step, the cross-linking group 102 generates a dehydration-condensed cross-linking group 106 by a dehydration condensation reaction 113.
Further, as a third stage, the dehydration-condensation product 107 of the cross-linking group formed by hydrogen bonding with the polar group on the particle surface is formed by the dehydration-condensed cross-linking group 106 by the polar group 103 and the hydrogen bond 111 on the particle surface.
As a fourth step, the dehydrated condensate 107 is heated and dehydrated 112 to produce the desired particles 108 whose surfaces are modified by the dehydration-condensed cross-linking groups.

  As an example for modifying the surface of the silica particles with a cross-linking group, the treatment amount of the silane coupling agent to the silica particles is preferably 1% by weight or more, more preferably 2% by weight or more with respect to the silica particles. To do. If it is the said range, the affinity of the silica particle with respect to an ionizing radiation curable resin composition can be made favorable. On the other hand, the treatment amount of the silane coupling agent to the silica particles is preferably 50% by weight or less, more preferably 30% by weight or less based on the silica particles. If it is the said range, generation | occurrence | production of the free silane coupling agent which was not used for the process of a silica particle can be suppressed favorably, the restoring property with respect to an external impact improves, and generation | occurrence | production of a crack and a crack is suppressed.

  The silica particle surface modification method using a silane coupling agent is not particularly limited as long as the dispersibility in an organic solvent and the affinity with an ionizing radiation curable resin can be improved. be able to. For example, the surface of the silica particles can be modified by adding a predetermined amount of a silane coupling agent to the dispersion of silica particles and performing an acid treatment, an alkali treatment, or a heat treatment as necessary.

  In addition, when using a silane coupling agent other than those described above, a suitable way to distinguish is whether the particle surface after modification is hydrophobic or hydrophilic. Specifically, the surface of the particles is modified with the silane coupling agent, dried and then made into a fine powder with a size of 1 mm or less using an agate mortar or the like. Identify by.

  In the present invention, not all of the silane coupling agent is introduced into the surface of the silica particles, and may be present as a monomer or a condensate in the composition for forming a refractive index layer containing an ionizing radiation curable resin or the like. . Since the silane coupling agent is excellent in affinity with the ionizing radiation curable resin and the silica particles, the silica particles can be stably dispersed in the composition for forming a refractive index layer. In addition, the silane coupling agent is incorporated in the film and acts as a cross-linking agent when cured by irradiation with ionizing radiation or heating, so compared with the case where the entire amount of the silane coupling agent is introduced to the silica particle surface. Thus, the performance of the refractive index layer is easily improved.

  The above is a case where hollow particles and solid particles are formed of silica, but when the particles are formed of a material other than silica, surface modification suitable for each material may be appropriately performed.

  Moreover, even if it is a compound other than the said coupling agent, as long as it has the said characteristic, you may use as a compound for introduce | transducing the bridge | crosslinking formation group which concerns on this invention.

<1-5. Ionizing radiation curable resin>
In the present invention, the ionizing radiation curable resin is a resin that can be reacted and cured by irradiation with ionizing radiation. In view of productivity, preferred resins include thermosetting resins, ultraviolet curable resins, and resins that can be cured by using heat and radiation in combination.

  The content of the ionizing radiation curable resin in the refractive index layer is preferably 10% by weight or more, more preferably 20% by weight or more, and particularly preferably 30% by weight or more. On the other hand, it is preferably 70% by weight or less, more preferably 60% by weight or less, and particularly preferably 50% by weight or less. If it is within the above range, it is easy to exhibit a film strength that is low in refractive index and causes no problem in actual use.

  The ionizing radiation curable resin has an appropriate refractive index for ensuring antireflection performance, is easy to ensure adhesion with a light-transmitting substrate, and is a material that easily secures the mechanical strength of the refractive index layer. I just need it.

  The ionizing radiation curable resin preferably contains a compound having at least one hydrogen bond forming group and three or more ionizing radiation curable groups in one molecule. Thereby, at least a part of the ionizing radiation curable resin is formed of a compound having at least one hydrogen bond forming group and three or more ionizing radiation curable groups in one molecule. Here, the hydrogen bonding group means a functional group capable of forming a coating film by curing by heating a polymerization reaction or a crosslinking reaction between the same functional groups or different functional groups by heating. .

  By using a compound having an ionizing radiation-curable group that is cured by ionizing radiation and a hydrogen bond-forming group that is thermally cured alone or in combination with a curing agent, the composition for forming a refractive index layer is applied to the surface of the object to be coated. When this is applied and dried, and combined with irradiation with ionizing radiation and heating, chemical bonds such as crosslinks are formed in the coating film, and the coating film is easily cured efficiently. In addition, when the hollow particles and solid particles are formed of inorganic particles (especially silica), the hydroxyl group present on the surface of the particles and the compound are likely to form a covalent bond, and the hollow particles and / or the middle particles are easily formed. Since the actual particles and the radiation curable resin form a cross-linked bond, the strength of the refractive index layer can be improved.

  Examples of the ionizing radiation curable group used in a compound having at least one hydrogen bond forming group and three or more ionizing radiation curable groups in one molecule include photo radical polymerization, photo cation polymerization, photo Examples thereof include a functional group that undergoes a polymerization reaction such as anionic polymerization, an addition polymerization reaction that proceeds through photodimerization, or a condensation polymerization reaction. In particular, a group having an ethylenically unsaturated bond such as a (meth) acryloyl group, a vinyl group, or an allyl group is directly or indirectly subjected to the action of an initiator by irradiation with ionizing radiation such as an ultraviolet ray or an electron beam. Since a radical polymerization reaction can be caused, handling including a photocuring process is relatively easy. Among such functional groups, a (meth) acryloyl group is preferable because of excellent productivity and easy control of mechanical strength in the refractive index layer after curing.

  Examples of the hydrogen bond-forming group used in a compound having at least one or more hydrogen bond-forming groups and three or more ionizing radiation-curable groups in one molecule include alkoxy groups, hydroxyl groups, carboxyl groups, and amino groups. And epoxy groups. Among such functional groups, a hydroxyl group is excellent in affinity with these inorganic particles when hollow particles or solid particles are formed with inorganic particles (especially silica). Dispersibility in the inside can be improved. Hydroxyl groups are easily introduced into the compound, and when hollow particles or solid particles are used as inorganic particles, they are adsorbed on the hydroxyl groups on the surface of the particles. Can be uniformly dispersed. Therefore, the lifetime of the refractive index layer forming composition can be improved, and a film in which the transparency of the film and the film strength are not easily lowered due to aggregation of hollow particles and solid particles can be formed.

  As the compound having at least one hydrogen bond forming group and three or more ionizing radiation curable groups in one molecule, those having a hydrogen bond forming group such as a hydroxyl group are usually used. The hydrogen bond-forming group may be produced as a by-product during synthesis and mixed as a part of the monomer. Specifically, di (meth) acrylates such as ethylene glycol di (meth) acrylate and pentaerythritol di (meth) acrylate monostearate; trimethylolpropane tri (meth) acrylate and tris such as pentaerythritol tri (meth) acrylate (Meth) acrylates: Polyfunctional (meth) acrylates such as pentaerythritol tetra (meth) acrylate derivatives and dipentaerythritol penta (meth) acrylates.

  In addition to these, there are epoxy acrylate resins having a hydroxyl residue (for example, “Epoxy ester” manufactured by Kyoeisha Chemical Co., Ltd., “Lipoxy” manufactured by Showa High Polymer Co., Ltd.), urethane acrylate resins (various isocyanates and Resins obtained by polyaddition of a monomer having a hydroxyl group via a urethane bond (for example, “Shikou (registered trademark)” manufactured by Nippon Synthetic Chemical Industry Co., Ltd. and “urethane acrylate” manufactured by Kyoeisha Chemical Co., Ltd.)) Oligomers having a number average molecular weight (gel permeation chromatography; polystyrene-equivalent number average molecular weight measured by GPC (Gel Permeation Chromatography) method) containing a hydrogen bond-forming group such as 20,000 or less are also preferably used.

  These monomers and oligomers are excellent in the effect of increasing the crosslink density of the film, and have a high fluidity and excellent coating suitability because the number average molecular weight is as small as 20,000 or less.

  Furthermore, if necessary, a (co) polymer containing a monomer having a hydrogen bond-forming group, a reactive polymer having a number average molecular weight of 20,000 or more having a (meth) acrylate group in the main chain or side chain, etc. It can be preferably used. As these reactive polymers, for example, commercially available products such as “macromonomer” (manufactured by Toagosei Co., Ltd.) can be used, and a copolymer of methyl methacrylate and glycidyl methacrylate is polymerized in advance. Alternatively, a reactive polymer having a (meth) acrylate group may be obtained by condensing the glycidyl group of the copolymer with a carboxyl group of methacrylic acid or acrylic acid. In the present invention, the (co) polymer means a polymer and / or a copolymer.

  In the present invention, it is possible to easily adjust various properties of the refractive index layer by appropriately combining a monomer and / or oligomer having a number average molecular weight of 20,000 or less and a polymer having a number average molecular weight of 20,000 or more.

  The content of the compound having at least one hydrogen bond-forming group and three or more ionizing radiation curable groups in one molecule is preferably 10 parts by weight with respect to 100 parts by weight of the ionizing radiation curable resin. More preferably, the content is 30 parts by weight or more. On the other hand, the content of the compound is preferably 100 parts by weight or less with respect to 100 parts by weight of the resin. If it is the said range, the mechanical strength of a refractive index layer can be strengthened.

<1-6. Other ingredients>
In the composition for forming a refractive index layer for forming the refractive index layer, components other than the ionizing radiation curable resin, hollow particles, and solid particles, which are essential components, as long as the effects of the present invention are not impaired as necessary. May also be included. Components other than the ionizing radiation curable resin, hollow particles, and solid particles include solvents, polymerization initiators, curing agents, crosslinking agents, UV blockers, UV absorbers, surface conditioners (leveling agents), and others. Of the ingredients. Of the above materials, as an example, a surface conditioner (leveling agent), a polymerization initiator, and a curing agent will be described below.

<1-6-1. Surface conditioner (leveling agent)>
The refractive index layer may contain a surface conditioner (leveling agent) having compatibility with any of ionizing radiation curable resin, hollow particles and solid particles, and the leveling agent is preferably a silicon compound. . By including such a silicon-based compound, the film surface can be easily flattened, and slipperiness that contributes to the improvement of scratch resistance required for the antireflection laminate can be easily provided. “Compatibility” means that a silicon compound can be used to confirm the flatness and slipperiness of the coating film in the coating film containing the ionizing radiation curable resin, hollow particles and solid particles. Even when the amount is added, it means having an affinity to such an extent that a decrease in transparency due to white turbidity of the refractive index layer or an increase in haze cannot be confirmed.

  In the present invention, it is preferable that at least a part of the silicon-based compound is fixed to the outermost surface of the coating film by forming a covalent bond with the ionizing radiation curable resin by a chemical reaction. Thereby, slipperiness can be stably provided and long-term scratch resistance of the antireflection laminate can be maintained.

  The silicon compound preferably has a structure represented by the following chemical formula (2).

化学式（２）中、Ｒ^ａはメチル基等の炭素数１〜２０のアルキル基やフェニル基を示し、Ｒ^ｂは非置換、もしくはアミノ基、エポキシ基、カルボキシル基、水酸基、又は(メタ)アクリロイル基で置換された炭素数１〜２０のアルキル基、炭素数１〜３のアルコキシ基、又はポリエーテル変性基を示し、各Ｒ^ａ、Ｒ^ｂは互いに同一でも異なっていても良い。また、ｍは０〜２００、ｎは０〜２００の整数である。

In the chemical formula (2), R ^a represents an alkyl group having 1 to 20 carbon atoms such as ^a methyl group or a phenyl group, and R ^b is unsubstituted, or an amino group, an epoxy group, a carboxyl group, a hydroxyl group, or (meth) acryloyl. A C1-C20 alkyl group substituted with a group, a C1-C3 alkoxy group, or a polyether-modified group, wherein each R ^a and R ^b may be the same or different from each other; M is an integer from 0 to 200, and n is an integer from 0 to 200.

  Silicone compounds having a basic skeleton like the above general formula are generally known to have low surface tension and excellent water repellency and releasability, but various functional groups are introduced into the side chain or terminal. Thus, further effects can be imparted. For example, reactivity can be imparted by introducing an amino group, an epoxy group, a carboxyl group, a hydroxyl group, a (meth) acryloyl group, an alkoxy group, etc., and a covalent bond is easily formed by a chemical reaction with the ionizing radiation curable resin. Become.

  Such a compound can be obtained as a commercial product. For example, polyether-modified silicone oil TSF4460 (trade name, manufactured by GE Toshiba Silicone Co., Ltd.), X22-164E (trade name, manufactured by Shin-Etsu Silicone Co., Ltd.) Various modified silicone oils can be obtained according to the purpose.

  Such silicon compounds may be used alone or in combination of two or more depending on the expected effect. By appropriately combining these compounds, various properties such as antifouling property, water / oil repellency, slipperiness, scratch resistance, durability, and leveling property can be adjusted to achieve the intended function.

  The content of the silicon-based compound is preferably 1.5% by weight or more, more preferably 2% by weight or more, and preferably 5% by weight based on the total weight of the ionizing radiation curable resin, the hollow particles and the solid particles. % By weight or less, more preferably 4% by weight or less. This is because if the content is 2% by weight or more, sufficient slipperiness can be imparted to the antireflection laminate, and if it is 4% by weight or less, the strength of the coating film can be easily secured.

<1-6-2. Polymerization initiator>
The polymerization initiator is not necessarily required in the present invention. However, ionizing radiation curable resins, hollow particles modified with crosslink forming groups and solid particles modified with crosslink forming groups, and ionizing radiation curable groups of other optional resins are polymerized by ionizing radiation irradiation. When reaction is difficult to occur, it is preferable to use an appropriate initiator in accordance with the reaction mode of the other resin and the particles.

  For example, when the ionizing radiation curable group of the ionizing radiation curable resin is a (meth) acryloyl group, a photo radical polymerization initiator is used. Examples of photo radical polymerization initiators include acetophenones, benzophenones, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, thiuram compounds, fluoro An amine compound etc. can be mentioned. More specifically, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, benzyldimethylketone, 1- (4-dodecyl) Phenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane -1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one, benzophenone, etc. Can do. Among these, 1-hydroxy-cyclohexyl-phenyl-ketone and 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-hydroxy-1- {4- [4- (2-Hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one is preferred because even a small amount initiates and accelerates the polymerization reaction upon irradiation with ionizing radiation . Any one of the above radical photopolymerization initiators can be used alone, or both can be used in combination. These may be commercially available, for example, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propane-1 -ON is available from Ciba Specialty Chemicals under the trade name Irgacure 127 (Irgacure 127, Irgacure is a registered trademark).

  When using a radical photopolymerization initiator, the radical photopolymerization initiator is preferably used in a proportion of 3 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the resin component mainly composed of ionizing radiation curable resin. Blend.

<1-6-3. Curing agent>
A hardening | curing agent is normally mix | blended in order to accelerate | stimulate the thermosetting reaction of the hydrogen bond forming group contained in some ionizing radiation curable resins. In addition, when hollow particles and solid particles are formed of silica, and at least a part of the particles are surface-treated silica particles, silanol groups present on the surface, the silane coupling agent used for the surface treatment, And in order to accelerate | stimulate thermosetting reactions, such as the unreacted part of the condensate of the said silane coupling agent, a hardening | curing agent is mix | blended.

  When the thermosetting polar group is a hydroxyl group, the curing agent usually has a compound having a basic group such as methylolmelamine, or a hydrolyzable group that generates a hydroxyl group by hydrolysis of a metal alkoxide or the like. A compound can be mentioned. As the basic group, an amine, nitrile, amide, or isocyanate group is preferably used, and as the hydrolyzable group, an alkoxy group is preferably used. In the latter case, in particular, an aluminum compound represented by the following chemical formula (3) and / or a derivative of the compound has good compatibility with a hydroxyl group, and is particularly preferably used.

Chemical formula (3)
AlR ₃
(In the chemical formula (3), the residues R ₃ may be the same or different and are halogen, alkyl having 10 or less carbon atoms, preferably 4 or less, alkyl, alkoxy, acyloxy, or hydroxy, and these groups may be all or Some may be replaced by chelating ligands)

  The compound can be selected from an aluminum compound and / or an oligomer and / or complex derived from the compound, and an inorganic acid aluminum salt or an organic acid aluminum salt.

  Specific examples include aluminum-sec-butoxide, aluminum-iso-propoxide, and complexes thereof with acetylacetone, ethyl acetoacetate, alkanolamines, glycols, and derivatives thereof.

  When a curing agent is used, the curing agent is preferably blended at a ratio of 0.05 parts by weight or more and 30.0 parts by weight or less with respect to a total of 100 parts by weight of the resin component mainly composed of ionizing radiation curable resin. To do.

<1-7. Refractive index layer>
The refractive index layer composed of each of the above components is generally a refractive index layer obtained by adding a solvent to each of the other essential components in addition to the above-described essential components and performing a dispersion treatment according to a general preparation method. A forming composition is prepared. And a refractive index layer can be formed by apply | coating the said composition to a base material, and drying and hardening after that. Since the solvent is required depending on the viscosity and fluidity when the above components are mixed, the composition for forming a refractive index layer may be prepared without using the solvent. Hereinafter, the adjustment method of a solvent, the composition for refractive index layer formation, and the formation method of a refractive index layer are demonstrated.

<1-7-1. Solvent>
When the ionizing radiation curable resin is used in a relatively large amount, the monomer and / or oligomer in the resin can function as a liquid medium, so that the refractive index layer forming composition can be obtained without using a solvent. May be prepared. Accordingly, a solvent may be used in order to prepare a composition for forming a refractive index layer having excellent coating properties by appropriately dissolving and dispersing solid components and adjusting the concentration.

  The solvent used for dissolving and dispersing the solid component of the refractive index layer is not particularly limited, and various organic solvents such as alcohols such as isopropyl alcohol, methanol and ethanol; ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. An ester such as ethyl acetate and butyl acetate; a halogenated hydrocarbon; an aromatic hydrocarbon such as toluene and xylene; or a mixture thereof.

  Among the above solvents, it is preferable to use a ketone-based organic solvent. When a composition for forming a refractive index layer is prepared using a ketone-based solvent, it becomes easy to apply thinly and uniformly on the surface of a light-transmitting substrate or the substrate of an antireflection laminate, and after coating, the solvent Since the evaporation rate is moderate and it is difficult to cause uneven drying, a large-area coating film having a uniform thickness can be easily obtained.

  Another reason that the solvent is preferably a ketone-based organic solvent is that even when a refractive index layer is formed on a hard coat (scratch-resistant function) layer having fine irregularities on the surface, it is applied uniformly. It is because it becomes easy to work. Specifically, when a hard coat layer is used as the support layer on the substrate side of the antireflection laminate, the surface of the hard coat layer is finely uneven to give the layer a function as an antiglare layer. In some cases, a refractive index layer as a low refractive index layer is formed on the intermediate refractive index layer or the high refractive index layer, or without the intermediate refractive index layer or the high refractive index layer. is there. When a composition for forming a refractive index layer is prepared using a ketone solvent, it can be applied evenly on such a fine uneven surface, and uneven coating can be easily prevented. The hard coat layer, medium refractive index layer, and high refractive index layer will be described later.

  As a ketone solvent, it contains a single solvent composed of one kind of ketone, a mixed solvent composed of two or more kinds of ketone, and one or two or more kinds of ketone solvents, and loses the properties as a ketone solvent. Examples of such mixed solvents may be mentioned. Of these, it is preferable to use a mixed solvent of different types. In this case, the ketone solvent is preferably contained in an amount of 70% by weight or more, particularly 80% by weight or more of the whole solvent.

  The amount of the solvent can be dissolved and dispersed uniformly in each component, and is adjusted as appropriate so that the hollow particles and solid particles do not aggregate even when left after preparation, and the concentration is not too dilute during coating. To do. It is preferable to prepare a high-concentration refractive index layer-forming composition by reducing the amount of the solvent added within a range that satisfies this condition. Thereby, it can preserve | save in the state which reduced the capacity | capacitance, It can dilute and use to a suitable density | concentration at the time of a coating operation. When the total amount of the solid content and the solvent is 100 parts by weight, the solvent is 50 to 95.5 parts by weight, more preferably 10 to 30 parts by weight based on the total solids of 0.5 to 50 parts by weight. By using the solvent in a proportion of 70 to 90 parts by weight with respect to parts, a composition for forming a refractive index layer that is particularly excellent in dispersion stability and suitable for long-term storage can be obtained.

<1-7-2. Preparation Method of Refractive Index Layer Composition>
Each of the above essential components and each desired component can be mixed in any order to prepare a refractive index layer forming composition. If the hollow particles or solid particles are colloidal, they can be mixed as they are. If it is powdery, a medium such as beads is added to the obtained mixture, and the mixture is appropriately dispersed with a paint shaker, bead mill, or the like to obtain a composition for forming a refractive index layer.

<1-7-3. Method for forming refractive index layer>
In order to form the refractive index layer, the composition for forming a refractive index layer obtained as described above is applied to the surface of the object to be coated, dried, and then cured by irradiation with ionizing radiation and / or heating.

  Examples of the method for applying the refractive index layer forming composition include spin coating, dipping, spraying, slide coating, bar coating, roll coater, meniscus coater, flexographic printing, screen printing, Examples thereof include a bead coater method. Moreover, what is necessary is just to use a well-known method suitably for drying, irradiation of ionizing radiation, and / or a heating after application | coating.

  The thickness of the refractive index layer obtained by applying the composition for forming a refractive index layer is preferably 0.05 μm or more and 0.15 μm or less. When the film thickness of the refractive index layer is 0.05 μm or more, sufficient film forming properties as the refractive index layer can be obtained. Moreover, material cost can be reduced by making the film thickness of the said refractive index layer into 0.15 micrometer or less.

<2. Antireflection laminate>
The antireflection laminate according to the present invention comprises a transparent resin substrate and a refractive index layer as essential elements, and in order to improve the strength and / or optical properties of the laminate, a hard coat layer, an antiglare layer, and an antistatic layer A functional layer such as the above may be formed.

<2-1. Layer structure of antireflection laminate>
A cross-sectional view of an example of the antireflection laminate according to the present invention is conceptually shown in FIG. In the cross-sectional views of FIG. 3 and subsequent figures, the thickness direction (vertical direction in the figure) is greatly enlarged and exaggerated from the scale in the plane direction (left and right direction in the figure) for ease of explanation. The antireflection laminate 10 shown in FIG. 3 has a hard coat layer 40 and a refractive index layer (low refractive index layer) 30 on the surface of the transparent resin substrate 20 on the viewer 80 side from the side close to the transparent resin substrate 20. Is formed.
In the antireflection laminate according to the present invention, the refractive index layer is provided on one surface side of the transparent resin base material as the low refractive index layer having the smallest refractive index, either directly or via another layer. It is preferable. Moreover, it is preferable that the said other layer is a hard-coat layer. By adopting such a layer configuration, since the refractive index layer having a low refractive index and excellent scratch resistance is provided on the most observer-side surface of the antireflection laminate, the reflectivity of the display surface is reduced. And good visibility can be obtained. Further, when the refractive index layer is provided on the observer side of the transparent resin substrate via the hard coat layer, the hard coat layer is subjected to an impact that the refractive index layer can withstand, The damaged area of the layer can be reduced, and the transparent resin substrate and other layers on the display side can be protected.
Hereinafter, the transparent resin base material, which is an essential base material other than the refractive index layer, and other functional layers such as a hard coat layer provided as necessary, which form the antireflection laminate according to the present invention, will be described in order. .

<2-2. Transparent resin substrate>
The transparent resin base material constituting the antireflection laminate may be a plate or a film (or a sheet; the same applies hereinafter). However, since the functional layers such as the refractive index layer and the hard coat layer are laminated, the substrate is preferably thin. The higher the transparency of the transparent resin substrate, the better. However, the light transmittance in the visible light region of 380 to 780 nm is preferably 70% or more, more preferably 80% or more. The light transmittance can be measured using a spectrophotometer (for example, UV-3100PC manufactured by Shimadzu Corporation) and a value measured in the air at room temperature.

  Preferred examples of the base material include triacetate cellulose (TAC), polyethylene terephthalate (PET), diacetyl cellulose, acetate butyrate cellulose, polyether sulfone, acrylic resin, polyurethane resin, polyester, polycarbonate, polysulfone, and polyether. And films formed of various resins such as trimethylpentene, polyetherketone, (meth) acrylonitrile, and cyclic polyolefin.

  The thickness of the substrate is preferably 30 μm or more, more preferably 50 μm or more, while the thickness of the substrate is preferably 200 μm or less.

  When a polar group having thermosetting properties is used for the radiation curable resin, the composition for forming a refractive index layer is directly or directly on the surface of the transparent resin base material to be coated. By applying, drying, and curing through this layer, the adhesion of the coating film to the surface of the object to be coated can be obtained by the action of the polar group.

<2-3-1. Hard coat layer>
In the antireflection laminate according to the present invention, it is preferable that the refractive index layer is provided on the observer side of the transparent resin substrate via a hard coat layer. By adopting such a layer structure, the hard coat layer reduces the damage area of the refractive index layer when subjected to an impact that the refractive index layer can withstand, and is a transparent resin on the display side. It has a function of protecting the substrate and other layers.
The hard coat layer is usually formed using an ionizing radiation curable resin. In the present specification, the “hard coat layer” means a layer having a hardness of H or higher in a pencil hardness test shown in JIS K5600-5-4: 1999.

As the ionizing radiation curable resin for forming the hard coat layer, a resin having an acrylate functional group is preferable. Specific examples include relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyether resins, and polyhydric alcohols. . Also, di (meth) acrylates such as ethylene glycol di (meth) acrylate and pentaerythritol di (meth) acrylate monostearate; tri (meth) such as trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate Examples of polyfunctional compounds such as acrylates; polyfunctional (meth) acrylates such as pentaerythritol tetra (meth) acrylate derivatives and dipentaerythritol penta (meth) acrylate; and oligomers such as epoxy acrylate and urethane acrylate it can.
Further, a hard coat layer in which the inorganic particles or the organic particles whose surfaces are coated within a range not impairing the transparency, a covalent bond is formed between the particles and the hard coat component, and the hardness is improved may be used.

  About the photoinitiator used with the said ionizing radiation curable resin, the method of film forming, etc., it selects from the thing illustrated previously suitably, and uses it.

  The film thickness after curing of the hard coat layer is preferably 0.1 μm or more, more preferably 0.8 μm or more, while the film thickness is preferably 100 μm or less, more preferably 20 μm or less. If the film thickness is 0.1 μm or more, sufficient hard coat performance can be easily obtained, and if it is 100 μm or less, sufficient strength can be easily obtained against external impact.

  In the present invention, the hard coat layer made of the ionizing radiation curable resin may have the functions of a medium refractive index layer, a high refractive index layer, and an antistatic layer as described later.

<2-3-2. Antiglare layer>
The antiglare layer is usually composed of an ionizing radiation curable resin and particles for the antiglare layer. By including particles for the antiglare layer, antiglare performance can be imparted in addition to scratch resistance.

  The ionizing radiation curable resin can be appropriately selected from those preferably used for the hard coat layer.

  As the shape of the particles for the antiglare layer, for example, a spherical shape may be used. Examples of the spherical shape include a true spherical shape and an elliptical shape. Preferably, a spherical shape is used.

  The material for the antiglare layer particles may be either inorganic or organic. The particles for the antiglare layer usually exhibit antiglare properties, and it is preferable to use a transparent material. Examples of such particles for the antiglare layer include silica beads as inorganic beads, and plastic beads as organic beads.

  When plastic beads are used, those having a refractive index of 1.40 to 1.60 are preferably used. The reason for limiting the refractive index of the plastic beads to the above range is as follows. That is, the refractive index of an ionizing radiation curable resin, particularly an acrylate or methacrylate resin is usually 1.45 to 1.55, and plastic beads having a refractive index as close as possible to the refractive index of the ionizing radiation curable resin should be selected. This is because the antiglare property can be improved without impairing the transparency of the coating film.

  Specific examples of plastic beads having a refractive index close to that of ionizing radiation curable resin include acrylic beads (refractive index: 1.49) such as polymethyl methacrylate beads, polycarbonate beads (refractive index: 1.58), Polystyrene beads (refractive index: 1.50), styrene beads (refractive index: 1.59), melamine beads (refractive index: 1.57), polyvinyl chloride beads (refractive index: 1.54), polyacryl styrene beads (Refractive index: 1.57), acrylic-styrene beads (refractive index: 1.54), polyethylene beads (refractive index: 1.53), and the like. As long as the refractive index is in the above range, other materials can be used.

  The particle diameter of these antiglare layer particles is preferably 3 μm or more and 8 μm or less. Further, the content of the particles for the antiglare layer is preferably 2 parts by weight or more, more preferably 10 parts by weight or more with respect to 100 parts by weight of the ionizing radiation curable resin, while the content is preferably 30 parts by weight. Part or less, more preferably 25 parts by weight or less.

  When the antiglare layer is formed by applying and curing the coating liquid, it is preferable to ensure dispersion of the particles for the antiglare layer in the coating liquid. Specifically, in the coating liquid in which the particles for the antiglare layer are mixed in the ionizing radiation curable resin, it may be necessary to well agitate and disperse the particles for the antiglare layer that are precipitated during use. In order to eliminate such inconvenience, silica beads having a particle size of usually 0.5 μm or less, preferably 0.1 μm or more and 0.25 μm or less as an anti-settling agent in the coating solution to form an antiglare layer. May be added. In addition, although this silica bead is effective in preventing sedimentation of the organic filler as it is added, it may affect the transparency of the coating film. Therefore, it is preferable that the content of the silica beads is within a range that does not impair the transparency of the coating film and can prevent sedimentation. Specifically, it is preferable to add silica beads less than about 0.1 parts by weight with respect to 100 parts by weight of the ionizing radiation curable resin.

  The film thickness after curing of the antiglare layer is preferably 0.1 μm or more, more preferably 0.8 μm or more, while the film thickness is preferably 100 μm or less, more preferably 20 μm or less. If the film thickness is 0.1 μm or more, sufficient hard coat performance can be easily obtained, and if it is 100 μm or less, sufficient strength can be easily obtained against external impact.

In the antiglare layer, the average particle diameter of the particles for the antiglare layer is R (μm), the ten-point average roughness of the unevenness on the surface of the antiglare layer is Rz (μm), and the unevenness average interval on the surface of the antiglare layer is When Sm (μm) is set and the average inclination angle of the concavo-convex portion is θa, it is preferable to satisfy the following four expressions simultaneously.
30 ≦ Sm ≦ 200,
0.90 ≦ Rz ≦ 1.60,
1.3 ≦ θa ≦ 2.5,
0.3 ≦ R ≦ 10

According to another preferred embodiment of the antiglare layer, when the refractive indexes of the antiglare layer particles and the ionizing radiation curable resin are n1 and n2, respectively, the following formula is satisfied: An antiglare layer having a haze value inside the antiglare layer of 55% or less is preferred.
Δn = | n1-n2 | <0.1

<2-3-3. Antistatic layer>
The anti-reflective laminate has an anti-static layer as necessary to prevent the generation of static electricity and prevent the adhesion of dust, and to prevent external static electricity damage when it is assembled in a liquid crystal display. It may be formed. In this case, the antistatic layer preferably has a surface resistance of 10 ¹² Ω / □ or less after the formation of the antireflection laminate. However, even when the surface resistance is 10 ¹² Ω / □ or more, by providing the antistatic layer, it is easier to suppress the adhesion of dust than the antireflection laminate having no antistatic layer.

  When the antistatic layer is formed of a resin, the antistatic layer contains a resin and an antistatic agent. Here, as the resin for forming the antistatic layer, the same resin as that used in the hard coat layer may be used.

  Examples of the antistatic agent contained in the antistatic layer-forming resin include various cationic antistatic agents having a cationic group such as a quaternary ammonium salt, a pyridinium salt, and first to third amino groups; sulfonic acid Anionic antistatic agents having anionic groups such as bases, sulfate ester bases, phosphate ester bases, phosphonate bases; amphoteric antistatic agents such as amino acids and aminosulfate esters; amino alcohols, glycerols, polyethylene glycols Nonionic antistatic agents such as those based on conductive polymers of conductive polymers such as polyacetylene, polyaniline, and polythiophene (for example, 3,4-ethylenedioxythiophene (PEDOT)); tin and titanium Such as organometallic compounds such as alkoxides and their acetylacetonate salts Various surfactant type antistatic agents such as genus chelate compounds; and the above-mentioned antistatic agent increasing the molecular weight of the polymeric antistatic agent and the like. In addition, a tertiary amino group, a quaternary ammonium group, a monomer or oligomer having a metal chelate portion and polymerizable by ionizing radiation, and an organometallic compound such as a coupling agent having a functional group polymerizable by ionizing radiation And other polymerizable antistatic agents.

  Examples of other antistatic agents include fine particles having a particle size of 100 nm or less, such as tin oxide, tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO), indium-doped zinc oxide (AZO), antimony oxide, and indium oxide. be able to. In particular, when the particle size is 100 nm or less, which is equal to or less than the wavelength of visible light, it is easy to ensure the transparency of the antistatic layer, and the advantage that the transparency of the antireflection laminate is hardly impaired is exhibited.

  By mixing the antistatic agent in the coating liquid for forming the hard coat layer and the antiglare layer, two properties of antistatic performance and hard coat performance, or two properties of antistatic performance and antiglare performance are provided. It becomes easy to obtain a coating film having improved properties at the same time.

<2-3-4. High refractive index layer and medium refractive index layer (refractive index layer having a refractive index of 1.46 to 2.00)>
The high refractive index layer and the medium refractive index layer usually mainly contain an ionizing radiation curable resin and particles for adjusting the refractive index. As the ionizing radiation curable resin, the same as the hard coat layer can be used. Moreover, what is necessary is just to make it the same as a hard-coat layer also about the photoinitiator used as needed, various additives, a formation method, etc.

  Examples of the particles for adjusting the refractive index include fine particles having a particle diameter of 100 nm or less. Examples of such fine particles include zinc oxide (refractive index: 1.90), titania (refractive index: 2.3 to 2.7), ceria (refractive index: 1.95), and tin-doped indium oxide (refractive index: 1). .95), at least one selected from the group consisting of antimony-doped tin oxide (refractive index: 1.80), yttria (refractive index: 1.87), and zirconia (refractive index: 2.0). it can.

  The particles for adjusting the refractive index are preferably those having a refractive index higher than that of the ionizing radiation curable resin. The refractive index is determined by the content of the particles for adjusting the refractive index in the high refractive index layer and the middle refractive index layer. That is, since the refractive index increases as the content of the particles for adjusting the refractive index increases, the refractive index can be freely adjusted in the range of 1.46 to 2.00 by changing the composition ratio of the ionizing radiation curable resin and the particles. Can be controlled.

  The medium refractive index layer and the high refractive index layer are vapor-deposited inorganic oxides having a high refractive index such as titanium oxide and zirconium oxide formed by vapor deposition methods such as chemical vapor deposition (CVD) and physical vapor deposition (PVD). It can be made into a film or a coating film in which inorganic oxide particles having a high refractive index such as titanium oxide are dispersed. As the medium refractive index layer, a light transmissive layer having a refractive index of 1.46 to 1.80 can be used, and as the high refractive index layer, a light transmissive layer having a refractive index of 1.65 or more can be used. .

  In the antireflection laminate according to the present invention, when the above-described medium refractive index layer and / or high refractive index layer is provided, the medium refractive index layer is located at a position closer to the display side than the refractive index layer (low refractive index layer). When providing a high refractive index layer, and further providing a medium refractive index layer and a high refractive index layer, in order to reduce reflectivity, the medium refractive index layer, the high refractive index layer, and A low refractive index layer is provided. Moreover, in such a form, when providing a hard-coat layer further, the said hard-coat layer is provided in the surface at the side of the transparent resin base material of the said medium refractive index layer.

<2-4. Modified example of layer structure of antireflection laminate>
4 to 7 are cross-sectional views schematically showing other examples of the layer configuration of the antireflection laminate according to the present invention.
FIG. 4 illustrates the antireflection laminate 10 in which a refractive index layer (low refractive index layer) is provided on the viewer 80 side of the transparent resin substrate 20.
In FIG. 5, the antireflective layer in which the high refractive index layer 50 and the refractive index layer (low refractive index layer) are provided in this order on the viewer 80 side of the transparent resin substrate 20 from the side close to the transparent resin substrate. A laminate 10 is illustrated.
In FIG. 6, the hard coat layer 40, the medium refractive index layer 60, the high refractive index layer 50, and the refractive index layer (low refractive index layer (low refractive index) are arranged on the viewer 80 side of the transparent resin substrate 20 from the side close to the transparent resin substrate. The antireflection laminate 10 in which the rate layer 30 is provided in this order is illustrated.
In FIG. 7, the antistatic layer 70, the hard coat layer 40, the high refractive index layer 50, and the refractive index layer (low refractive index layer) are arranged on the viewer 80 side of the transparent resin substrate 20 from the side close to the transparent resin substrate. The antireflection laminate 10 in which the (layer) 30 is provided in this order is illustrated.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and has the same operational effects can be used. Included in the technical scope.

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

<3-1-1. Preparation of surface-modified hollow particles (surface-modified hollow silica fine particles A)>
As a hollow particle, an isopropanol dispersion of hollow silica fine particles (manufactured by Catalyst Chemical Industry Co., Ltd.) is solvent-substituted from isopropyl alcohol to methyl isobutyl ketone (hereinafter sometimes referred to as MIBK) using a rotary evaporator, and silica fine particles are obtained. A 20% by weight dispersion was obtained. By adding 5% by weight of 3-methacryloxypropylmethyldimethoxysilane to 100% by weight of this methyl isobutyl ketone dispersion and subjecting it to heat treatment at 50 ° C. for 1 hour, the surface-treated hollow silica fine particles 20% by weight of methyl isobutyl ketone A dispersion was obtained.

<3-1-2. Preparation of surface-modified hollow particles (surface-modified hollow silica fine particles C)>
As a hollow particle, an isopropanol dispersion of hollow silica fine particles (manufactured by Catalytic Chemical Industry Co., Ltd.) was subjected to solvent substitution from isopropyl alcohol to methyl isobutyl ketone using a rotary evaporator to obtain a dispersion of silica fine particles of 20% by weight. . By adding 5% by weight of 3-glycidoxypropylmethyldimethoxysilane to 100% by weight of this methyl isobutyl ketone dispersion and heat-treating it at 50 ° C. for 1 hour, 20% by weight of methyl isobutyl having a surface-treated hollow silica fine particle was treated. A ketone dispersion was obtained.

<3-2-1. Preparation of surface-modified solid particles (surface-modified solid silica fine particles A)>
As solid particles, 5% by weight of 3-methacryloxypropylmethyldimethoxysilane is added to 100 parts by weight of methyl isobutyl ketone-dispersed silica sol (MIBK-ST: trade name, manufactured by Nissan Chemical Industries, Ltd., silica solid content 20% by weight). Then, a surface-treated solid silica fine particle 20% by weight methyl isobutyl ketone dispersion was obtained by heat treatment at 50 ° C. for 1 hour.

<3-2-2. Preparation of surface-modified solid particles (surface-modified solid silica fine particles B)>
To a solution consisting of 7.8% by weight of mercaptopropyltrimethoxysilane and 0.2% by weight of dibutyltin dilaurate in dry air, 20.6% by weight of isophorone diisocyanate was added dropwise at 50 ° C. over 1 hour with stirring. The mixture was stirred at 60 ° C. for 3 hours. To this, 71.4% by weight of pentaerythritol triacrylate was added dropwise at 30 ° C. over 1 hour, and then heated and stirred at 60 ° C. for 3 hours to obtain Compound (1). Next, under nitrogen flow, methanol silica sol (methanol solvent colloidal silica dispersion: trade name, manufactured by Nissan Chemical Industries, Ltd., silica solid content 30% by weight) 88.5% by weight (solid content 26.6% by weight), synthesis A mixed solution of 8.5% by weight of Compound (1) and 0.01% by weight of p-methoxyphenol was stirred at 60 ° C. for 4 hours. Subsequently, 3% by weight of methyltrimethoxysilane was added to the reaction mixture as compound (2), stirred at 60 ° C. for 1 hour, 9% by weight of orthoformate methyl ester was added, and heated at the same temperature for 1 hour. A methanol dispersion liquid of 35% by weight of solid silica fine particles whose surface was treated was obtained by the treatment.

<3-2-3. Preparation of surface-modified solid particles (surface-modified solid silica fine particles C)>
As solid particles, methyl isobutyl ketone-dispersed silica sol (MIBK-ST: trade name, manufactured by Nissan Chemical Industries, Ltd., silica solid content: 20% by weight) is added to 5% by weight of 3-glycidoxypropylmethyldimethoxysilane in 100 parts by weight. By adding and heat-treating at 50 ° C. for 1 hour, a surface-treated solid silica fine particle 20 wt% methyl isobutyl ketone dispersion was obtained.

<Example 1>
<3-3-1. Preparation of composition for forming low refractive index layer>
Components having the following composition were mixed to prepare a composition for forming a low refractive index layer.

Surface-modified hollow silica fine particles A (20% by weight methyl isobutyl ketone hollow silica fine particles)
: 15.0 parts by weight of surface modified solid silica fine particles A (solid silica fine particles 20% by weight methyl isobutyl ketone)
: 0.4 parts by weight pentaerythritol triacrylate (PETA)
: 1.2 parts by weight dipentaerythritol hexaacrylate (DPHA)
: 0.4 parts by weight Irgacure 127 (trade name, manufactured by Ciba Specialty Chemicals)
: 0.1 part by weight X-22-164E (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
: 0.15 parts by weight Methyl isobutyl ketone: 83.5 parts by weight

<3-3-2. Preparation of composition for forming hard coat layer>
The composition of the following composition was mix | blended and the composition for hard-coat layer formation was prepared.

Surface-modified solid silica fine particle B (solid silica fine particle 35% by weight methyl isobutyl ketone)
: 25.0 parts by weight urethane acrylate (purple light UV1700-B: trade name, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
: 25.0 parts by weight Irgacure 184 (trade name, manufactured by Ciba Specialty Chemicals)
: 0.2 part by weight Methyl ethyl ketone: 49.8 parts by weight

<3-4. Preparation of substrate / hard coat layer / low refractive index layer film>
On the 80 μm thick triacetate cellulose (TAC) film (manufactured by Fuji Photo Film Co., Ltd.), the composition for forming a hard coat layer having the above composition is bar-coated, and after removing the solvent by drying, an ultraviolet irradiation device (fusion UV) System Japan Co., Ltd., light source H pulp), substrate / hard coat having a hard coat layer with a film thickness of about 15 μm by irradiating with ultraviolet rays at an irradiation dose of 10 mJ / cm ² and curing the hard coat layer A layer film was obtained.

On the obtained base material / hard coat layer film, the above-mentioned composition for forming a low refractive index layer is bar-coated, and after removing the solvent by drying, an ultraviolet irradiation device (Fusion UV System Japan Co., Ltd., Using a light source H bulb), UV irradiation was performed at an irradiation dose of 200 mJ / cm ² , and the coating film was cured to obtain an antireflection laminate of substrate / hard coat layer / low refractive index layer.
The film thickness of the low refractive index layer was set so that the minimum value of the reflectance measured using a spectrophotometer (UV-3100PC) manufactured by Shimadzu Corporation was around 550 nm.

  Since PETA and DPHA are almost entirely polymerized, the content of solid silica particles in the ionizing radiation curable resin composition is considered to be substantially the same as the content of solid silica particles in the ionizing radiation curable resin. It's okay.

The following four points were measured for the antireflection laminate of the base material / hard coat layer / low refractive index layer obtained as described above.
<3-5-1. Reflectance measurement>
Using a spectrophotometer (UV-3100PC) manufactured by Shimadzu Corporation, the minimum reflectance when the incident angle and the reflection angle were 5 ° was measured.

<3-5-2. Haze value measurement>
The haze value of the outermost surface of the antireflection laminate was measured according to JIS K7105: 1981 “Testing method for optical properties of plastic”.

<3-5-3. Scratch evaluation test (steel wool resistance)>
Using # 0000 steel wool, the presence or absence of scratches was visually confirmed when the load was changed and the surface of the optical laminate was reciprocated 20 times. The evaluation criteria were as follows.

○: No scratches △: Several scratches (1-10) are observed ×: Many scratches (10 or more) are observed

<3-5-4. Hardness evaluation test (pencil hardness measurement)>
The surface of the optical layered body was evaluated by visually observing the presence or absence of scratches on the surface of the optical layered body by drawing five lines under a load of 500 g using a predetermined pencil. The pencil hardness when not scratched was checked. The results are shown in Table-1.

<Example 2>
An antireflection laminate was produced in the same manner as in Example 1 except that the particle diameter of the surface-modified solid silica fine particles A was changed. The evaluation results are shown in Table 1 together with the particle diameters of the surface-modified solid silica fine particles.

<Example 3>
An antireflection laminate was produced in the same manner as in Example 1 except that the particle diameter of the surface-modified hollow silica sol A and the particle diameter of the surface-modified solid silica fine particles A were changed. The evaluation results are shown in Table 1 together with the particle diameter of the surface-modified hollow silica sol A and the particle diameter of the surface-modified solid silica fine particles A.

<Example 4>
An antireflection laminate was produced in the same manner as in Example 1 except that the MIBK-dispersed hollow silica fine particle dispersion and the MIBK-dispersed solid silica sol were mixed and surface-modified at the same time. The evaluation results are shown in Table 1 together with the particle diameters of the surface-modified solid silica fine particles.

<Comparative Example 1>
An antireflection laminate was produced in the same manner as in Example 1 except that the surface-modified solid silica fine particles A were not used. The evaluation results are shown in Table-1.

<Comparative example 2>
An antireflection laminate was produced in the same manner as in Example 1 except that untreated MIBK-dispersed solid silica sol MIBK-ST was used in place of the surface-modified solid silica fine particles A. The evaluation results are shown in Table-1.

<Comparative Example 3>
An antireflection laminate was produced in the same manner as in Example 2 except that the surface-modified solid silica fine particles B were used in place of the surface-modified solid silica fine particles A. The evaluation results are shown in Table-1.

<Comparative Example 4>
An antireflection laminate was prepared in the same manner as in Example 3 except that the surface-modified solid silica fine particles B were used in place of the surface-modified solid silica fine particles A. The evaluation results are shown in Table-1.

<Comparative Example 5>
Low refractive index layer in the same manner as in Example 1 except that the surface-modified solid silica fine particles C are used instead of the surface-modified solid silica fine particles A and the surface-modified hollow silica fine particles C are used instead of the surface-modified hollow silica fine particles A. A forming composition was prepared. The composition became cloudy, and aggregates were observed on the film surface when the antireflection laminate was produced.

FIG. 1 is a diagram schematically showing the mechanism of modification of the particle surface by the cross-linking group according to the present invention. FIG. 2 is a diagram schematically showing another mechanism of modification of the particle surface by the cross-linking group according to the present invention. FIG. 3 is a cross-sectional view schematically showing an example of the antireflection laminate according to the present invention. FIG. 4 is a cross-sectional view schematically showing an example of the antireflection laminate according to the present invention. FIG. 5 is a cross-sectional view schematically showing an example of the antireflection laminate according to the present invention. FIG. 6 is a cross-sectional view schematically showing an example of the antireflection laminate according to the present invention. FIG. 7 is a cross-sectional view schematically showing an example of the antireflection laminate according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silane coupling agent 2 Part used as coupling group 3 Spacer part 4 Ionizing radiation curable group 10 Antireflection laminated body 20 Transparent resin base material 30 Refractive index layer (low refractive index layer)
40 hard coat layer 50 high refractive index layer 60 middle refractive index layer 70 antistatic layer 80 observer

Claims (16)

An antireflection laminate having a refractive index layer having a refractive index of 1.45 or less,
The refractive index layer is a cured product obtained by irradiating a composition for forming a refractive index layer with ionizing radiation,
The refractive index layer forming composition comprises an ionizing radiation curable resin,
Cross-linking reactive hollow particles whose interior surrounded by the outer shell layer is porous or hollow and whose surface is modified with a cross-linking group;
Containing solid cross-linking reactive particles whose interior is neither porous nor hollow, and whose surface is modified with a cross-linking group;
The crosslink forming group on the surface of the hollow particle and the crosslink forming group on the surface of the solid particle are composed of a bonding group to the particle surface, a spacer part, and an ionizing radiation curable group, and have the same structure or structural differences. Even if there is, the ionizing radiation curable group has a common skeleton and is within a range in which the presence or absence of one hydrocarbon group having 1 to 3 carbon atoms is different, and is bonded to the particle surface. For the group, the skeleton is common, and the presence or absence of one hydrocarbon group having 1 to 3 carbon atoms is different. For the spacer portion, the skeleton is common, and It is within the range where only one hydrocarbon group having 1 to 3 carbon atoms or one functional group having 1 to 3 functional atoms containing different atoms and excluding hydrogen is different, or carbon of the skeleton Range in which the chain length only differs by 1 to 2 carbon atoms Antireflection stack which is a crosslinking group having a similar structure is.   The antireflection laminate according to claim 1, wherein the hollow particles and the solid particles are inorganic particles.   The reflection according to claim 1 or 2, wherein the hollow particles and the solid particles are at least one selected from the group consisting of metal oxides, metal nitrides, metal sulfides, and metal halides. Prevention laminate.   The modification of the crosslink-forming group on the surface of the hollow particle and the solid particle consists of a binding group, a spacer part and an ionizing radiation curable group on the particle surface, and has the same structure or structural differences. Even if there is, the ionizing radiation curable group has a common skeleton and is in a range in which the presence or absence of one hydrocarbon group having 1 to 3 carbon atoms is different, and is a bonding group to the particle surface. In terms of, the skeleton is common and the groups other than the spacer portion bonded to the bonding group are within the range in which the presence or absence of one hydrocarbon group having 1 to 3 carbon atoms is different, and the spacer portion As for, the skeleton is common and the presence or absence of one functional group having 1 to 3 hydrocarbon groups having 1 to 3 carbon atoms or 1 to 3 functional atoms having different atoms and excluding hydrogen is different. Or the carbon chain length of the skeleton is Characterized in that it is carried out using a coupling agent having a similar structure are within the scope of atom 1-2 min only different antireflective laminate according to any one of claims 1 to 3.   1 to 200 parts by weight of the coupling agent with respect to 100 parts by weight of the hollow particles, and 1 to 200 parts by weight of the coupling agent with respect to 100 parts by weight of the solid particles. The antireflective laminate according to claim 4, wherein the antireflective laminate is modified by using a part or less. The average particle size A of the solid particles and the average particle size B of the hollow particles have the following relationship:
10 nm ≦ A ≦ 40 nm;
30 nm ≦ B ≦ 60 nm; and A ≦ B,
The antireflection laminate according to any one of Claims 1 to 5, wherein   The antireflective laminate according to claim 6, wherein the refractive index layer contains 5 to 50 parts by weight of the hollow particles with respect to 100 parts by weight of the solid particles. The average particle size A of the solid particles and the average particle size B of the hollow particles have the following relationship:
30 nm <A ≦ 100 nm;
30 nm ≦ B ≦ 60 nm; and A> B,
The antireflection laminate according to any one of Claims 1 to 5, wherein   The antireflective laminate according to claim 8, wherein the refractive index layer contains 5 to 50 parts by weight of the hollow particles with respect to 100 parts by weight of the solid particles.   At least a part of the ionizing radiation curable resin is formed of a compound having at least one or more hydrogen bond forming groups and three or more ionizing radiation curable groups in one molecule, The antireflection laminate according to any one of claims 1 to 9.   The antireflection laminate according to any one of claims 1 to 10, wherein the ionizing radiation curable group is an acryloyl group and / or a methacryloyl group.   The ionizing radiation curable resin, the hollow particles, and the solid particles are covalently bonded through the ionizing radiation curable group according to any one of claims 1 to 11. Antireflection laminate.   13. The antireflection laminate according to claim 1, wherein a film thickness of the refractive index layer is 0.05 μm or more and 0.15 μm or less.   14. The antireflection laminate according to claim 1, wherein a refractive index of the solid particles is smaller than a refractive index of the ionizing radiation curable resin.   15. The light-transmitting base material according to claim 1, wherein the refractive index layer is provided directly or via another layer as a low refractive index layer having the smallest refractive index. The antireflection laminate according to any one of the above.   The antireflection laminate according to claim 15, wherein the other layer is a hard coat layer.

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