CN1768280A - Polarizing plate and manufacturing method thereof, and image display device - Google Patents

Abstract

A method for manufacturing a polarizing plate comprising: bonding an antireflection film containing a transparent support and an antireflection structure including a plurality of layers different in refractive index each comprising a cured film to a polarizing film, wherein at least one layer of the plurality of layers different in refractive index is a layer having a higher refractive index than that of the transparent support and a thickness of 10 nm to 2 mum, and the antireflection film is bonded to the polarizing film after being subjected to a hydrophilization treatment so that a contact angle to water of a surface of the antireflection film to be bonded to the polarizing film falls within a range of 20 degrees to 50 degrees.

Description

Polarizing plate and its preparation method, and image display device

                    

The present invention relates to a polarizing plate using an antireflection film as at least one surface protective film, and an image display device using the antireflection film.

Background technique

The anti-reflection film is placed on the surface of the display to prevent the external reflection in various image display devices such as liquid crystal display (LCD), plasma display panel (PDP), electroluminescent display (ELD) and cathode ray tube display (CRT). Contrast reduction caused by reflection of light or glare of the image. For this reason, antireflection films are required to have high mechanical strength (such as abrasion resistance), chemical resistance, and weather resistance (such as heat and humidity resistance and light resistance).

As an antireflection layer for an antireflection film such as a high-refractive-index layer, a middle-refractive-index layer, and a low-refractive-index layer, a multilayer film in which metal oxide transparent thin films are stacked on each other has been widely used. Metal oxide transparent thin films are usually formed by chemical vapor deposition (CVD) or physical vapor deposition (PVD), especially vacuum evaporation which is one of the physical vapor deposition methods.

However, the method of forming transparent thin films of metal oxides by vapor deposition has a low yield and is not suitable for mass production. For this reason, a method of molding by coating with high productivity has been proposed.

When an antireflection film is prepared by coating, a high refractive index resin can be used to form a high refractive index layer. In addition, it can also be formed by dispersing finer inorganic particles having a high refractive index more finely and adding them to the film. The latter method is preferred due to the wide range of controllable refractive index and due to the excellent transparency and mechanical strength of the resulting film. By adding a large amount of inorganic fine particles with a high refractive index to the film while maintaining a finely dispersed state, a transparent high-refractive index layer with a relatively high refractive index is formed (see, for example, JP-A-8-110401, JP-A-8-179123, JP-A-8-179123, JP-A-11-153703, JP-A-2001-166104, JP-A-2001-188104, JP-A-2002-116323 and JP-A-2002-156508).

It is very effective to incorporate titanium dioxide fine particles having a very high refractive index into the high refractive index layer. However, titanium dioxide fine particles have a photocatalytic function. Therefore, when the high-refractive index layer (antireflection film) is used under sunlight for a long time, the fine particles decompose organic compounds contained in the high-refractive index layer, so that the mechanical strength and optical performance are significantly lowered. This phenomenon is particularly noticeable in the high-refractive index layer in which titanium dioxide fine particles remain in a finely dispersed state.

Therefore, it is desired to prepare a high-refractive index layer that can be produced by coating, contains titanium dioxide fine particles, and is also excellent in weather resistance (especially light resistance). However, this need has not been satisfactorily fulfilled.

It has been found that by performing a hydrophilization treatment to laminate the film on a polarizing film comprising polyvinyl alcohol and iodine, for example, a saponification treatment in which the film is immersed in an alkali solution, to use the film as a surface protective film of a polarizing plate , and this is where the purpose of the present invention lies, and the preceding problems are particularly prominent. This is due to the fact that the layers forming the anti-reflection structure are so thin that they are susceptible even if it is not a surface layer. Due to this effect, the following two cases are mentioned: (1) The added inorganic fine particles are destroyed and eluted under the influence of saponification treatment, especially titanium dioxide fine particles, which have inherent surface coatings that inhibit photocatalysis The substance is eluted in the alkali solution; and (2) the binder including the organic polymer used for bonding between titanium dioxide fine particles is hydrolyzed. These effects are particularly prominent in a layer containing a large amount of inorganic fine particles as a filler, especially a layer having a high refractive index.

However, in recent years, the screen size of a liquid crystal display device (LCD) has been increasing, and the number of liquid crystal display devices in which an anti-reflection film is installed has increased.

In a liquid crystal display device (LCD), a polarizer is an essential optical material. Generally, it is constructed so that the polarizing film is protected by two protective films. However, also providing an anti-reflection film having weather resistance and anti-reflection function increases the number of constituent layers of the display panel, thus being greatly limited in terms of both manufacturing cost and function performance. By imparting an anti-reflection function to a protective film of a liquid crystal display device, a display having weather resistance, physical protection performance, and anti-reflection performance can be expected with cost reduction and thickness reduction. Therefore, it has been desired to develop it.

Contents of the invention

The present invention has been accomplished under the background described above. An object thereof is to provide polarizing plates each having an anti-reflection layer excellent in mechanical strength and weather resistance at low cost and in large quantities, and this object is to provide the polarizers necessary in the processing of surface protective films each having an anti-reflection layer. The conditions of the saponification treatment step are optimized, and the elemental composition of the titanium dioxide particles, which are essential components contained in the antireflection layer, is optimized. Another object is to provide an image display device subjected to anti-reflection treatment in an appropriate manner.

The above objects of the present invention are achieved by polarizing plates using antireflection films of the following configurations (1) to (13) and image display devices of (14) and (15), respectively.

(1) A preparation method of a polarizer, comprising: bonding an anti-reflection film with a polarizing film, the anti-reflection film has a multilayer formed on one side of a transparent support body with a different refractive index and each layer includes a cured film. The formed anti-reflection structure is characterized in that at least one layer of the multilayers with different refractive indices is a layer with a refractive index higher than that of the transparent support and a thickness of 10 nm-2 μm, and the anti-reflection film is subjected to hydrophilic treatment After that, it is bonded to the polarizing film so that the contact angle of the bonding surface of the anti-reflection film with water is in the range of 20 degrees to 50 degrees.

(2) The method for producing a polarizing plate according to (1), characterized in that the hydrophilization treatment is performed so that the contact angle is in the range of 30-40 degrees.

(3) The method for producing a polarizing plate according to (1) or (2), characterized in that the hydrophilization treatment is performed so that the contact angle is in the range of 40-50 degrees.

(4) The method for producing a polarizing plate according to any one of (1) to (3), characterized in that the hydrophilization treatment includes a step of immersing the antireflection film in an alkaline solution for saponification.

(5) A preparation method of a polarizer, comprising: bonding an anti-reflection film with a polarizing film, the anti-reflection film has a multilayer formed on one side of a transparent support body with a different refractive index and each layer includes a cured film. The formed antireflection structure is characterized in that the surface of the antireflection film opposite to the surface on which the antireflection structure is formed is used as an adhesive surface, and only this adhesive surface is subjected to saponification so that the contact angle with water is between 10°- within 50 degrees.

(6) According to the preparation method of any one of (1)-(5), it is characterized in that the cured film forming the anti-reflection structure is formed by coating, drying and curing containing at least one film-forming solute and at least one A solvent coating composition is obtained.

(7) The production method of the polarizing plate produced by the method according to any one of (1) to (6), characterized in that the layer forming the antireflection structure contains inorganic fine particles.

(8) The preparation method of the polarizing plate prepared according to the method described in (7), characterized in that an anti-reflection film is used, wherein these multilayers include at least one high-refractive-index layer with a refractive index higher than that of the support and a refractive index layer. A low-refractive-index layer having a refractive index lower than that of the support, and a high-refractive-index layer is a constituent layer having a refractive index of 1.55-2.40, which contains inorganic fine particles containing titanium dioxide as a main component, and contains at least one selected from the group consisting of cobalt , aluminum and zirconium elements.

(9) The method for producing a polarizing plate according to (8), characterized in that each of the inorganic fine particles is covered with at least one compound selected from the group consisting of inorganic compounds, organometallic compounds and organic compounds that reduces or destroys photocatalytic activity.

(10) A polarizing plate characterized by being produced by the production method according to any one of (1)-(9).

(11) The polarizing plate according to (10), characterized in that in addition to the antireflection film in the surface protective film, a film for forming the polarizing plate is a surface bonded with the surface protective film and the polarizing film An optical compensation film having an optical compensation layer comprising an optically anisotropic layer which is a layer having negative birefringence and includes a compound having a discotic structural unit on the surface of the opposite surface protection film, the The disc-shaped face of the disc-shaped structural unit is inclined with respect to the surface protection film face, and the angle formed between the disc-shaped face of the disc-shaped structural unit and the surface protection film face varies in the thickness direction of the optically anisotropic layer.

(12) A liquid crystal display device having at least one polarizing plate according to (10) or (11).

(13) The liquid crystal display device as described in (12), which is characterized in that it is of a transmissive, reflective or semi-transmissive TN, STN, VA, IPS or OCB mode.

According to the contents of this specification, the antireflection film has a high refractive index layer containing inorganic fine particles containing at least one element selected from cobalt, aluminum, and zirconium and containing titanium dioxide as a main component; The low-refractive-index layer of the cured film, said copolymer includes repeating units derived from fluorine-containing vinyl monomers, and repeating units each having a (meth)acryloyl group in a side chain, the antireflection film in this specification Polarizers are prepared through saponification treatment under the saponification conditions. As a result, an antireflection film each having excellent mechanical strength and weather resistance (in particular, light resistance) can be provided as a polarizing plate for a surface protection film in large quantities at low cost.

Also, thereby it is possible to provide an image display device maintaining the aforementioned features.

Brief description of attached drawings

FIG. 1 is a schematic cross-sectional view showing a layer structure of a polarizing plate using an antireflection film excellent in antireflection performance as a surface protection film.

Fig. 2 is a schematic diagram showing an example of an apparatus for practicing the present invention.

[Description of Reference Signs and Symbols]

1 transparent support

2 hard coat

3 intermediate refractive index layers

4 high refractive index layer

5 low refractive index layer (outermost layer)

6 adhesive layers

7 polarizing film

8 Surface protection film on the opposite side

9 Adhesive layer

101 feeding

102 First Coating Station

103 The first drying area

104 The first ultraviolet irradiation equipment

105 Second Coating Station

106 second drying area

107 The second ultraviolet irradiation equipment

108 Third Coating Station

109 The third drying area

110 The third ultraviolet irradiation equipment

111 drying area

112 winder

Next, the present invention is described in detail.

The anti-reflection structure of the present invention comprises at least one low refractive index layer and at least one high refractive index layer. The films forming the respective layers are cured films, each of which can be obtained by coating, drying and curing a coating composition preferably containing at least one film-forming solute and at least one solvent. A film-forming solute herein refers to a substance that is wet-coated on a base material in a state of being dissolved or dispersed in at least one solvent used for dissolving or dispersing it, and substantially remains on the base material after the solvent is dried. Exist in film form. Incidentally, in this specification, the term "(value 1) to (value 2)" means "greater than or equal to (value 1) and less than or equal to (value 2).

[Transparent support body]

The transparent support used for the antireflection film of the present invention is preferably a plastic film. Plastic films include cellulose esters (e.g., triacetyl cellulose, diacetyl cellulose, propionyl cellulose, butyryl cellulose, acetylpropionyl cellulose, and nitrocellulose) and polyolefins (e.g., poly propylene, polyethylene and polymethylpentene) films. Triacetyl cellulose and polyolefin are preferably used for polarizing plates because of their small retardation and high optical uniformity. In particular, triacetyl cellulose is preferred when it is used for a liquid crystal display device.

When the transparent support is a triacetyl cellulose film, preferably the triacetyl cellulose solution prepared by dissolving triacetyl cellulose in a solvent (referred to as concentrated Liquid) cast triacetyl cellulose film prepared.

In particular, from the viewpoint of environmental protection, it is preferable to use a triacetyl cellulose dope prepared by dissolving triacetyl cellulose in a solvent substantially free of methylene chloride by a low-temperature dissolution method or a high-temperature dissolution method. Acetyl cellulose membrane. Detailed description can be found in Journal of Technical Disclosure ( KOUKAI GIHOU ) 2001-No.1745 of Japan Institute of Invention and Innovation.

A single-layer triacetyl cellulose film is produced by roll casting, tape casting, etc. disclosed in JP-A-7-11055, etc., and a triacetyl cellulose film including multiple layers is produced by JP-A-61-94725, Produced by the so-called co-casting method disclosed in JP-B-62-43846 and the like.

For example, raw flakes are dissolved in solvents such as halogenated hydrocarbons (e.g., dichloromethane), alcohols (e.g., methanol, ethanol, and butanol), esters (e.g., methyl formate and methyl acetate), and ethers ( For example, dioxane, dioxolane and diethyl ether). Various additives such as plasticizers, ultraviolet absorbers, degradation inhibitors, lubricants and release accelerators are added thereto, if necessary. The resulting solution (dope) is poured onto a support comprising a horizontal endless metal belt or roller using a dope feeding device (abbreviated as a mold).

For a single layer, a single dope is poured into a single layer, and for multiple layers, a low-concentration dope is co-cast on both sides of a high-concentration cellulose ester dope. The dope is then dried on the support to such an extent as to impart stiffness to the resulting membrane. The membrane is released from the support and then passed through a drying zone using various transport devices to remove the solvent.

The aforementioned solvent for dissolving triacetyl cellulose is usually dichloromethane. However, from the viewpoint of global environment and working environment, it is preferable that the solvent does not substantially contain halogenated hydrocarbons such as methylene chloride. The word "substantially free" means that the proportion of halogenated hydrocarbons in the organic solvent is less than 5% by weight (preferably less than 2% by weight). When a dope of triacetylcellulose is prepared using a solvent substantially free of methylene chloride or the like, it is preferable to use a specific dissolution method described later.

The first method is simply called the cooling dissolution method and will be described below. First, triacetylcellulose was gradually added to the solvent at a temperature around room temperature (-10 to 40° C.) while stirring. Then, the mixture is cooled to -100 to -10°C (preferably -80 to -10°C, more preferably -50 to -20°C, most preferably -50 to -30°C). Cooling can be done in a dry ice/methanol bath (-75°C) or in a cooled solution of diethylene glycol (-30 to -20°C). This cooling causes the mixture of triacetylcellulose and solvent to solidify. It is then heated to 0-200°C (preferably 0-150°C, more preferably 0-120°C, most preferably 0-50°C), thereby turning it into a solution in which triacetylcellulose is flowable in a solvent . The temperature may be raised simply by leaving the cured mixture at room temperature, or it may be raised in a warming bath.

The second method is simply called the high-temperature dissolution method, and will be described below. First, triacetylcellulose was gradually added to the solvent at a temperature around room temperature (-10 to 40° C.) while stirring. The triacetyl cellulose solution of the present invention is preferably pre-swollen by adding triacetyl cellulose to a mixed solvent containing different solvents. In this method, triacetylcellulose is preferably dissolved to a concentration of 30% by weight or less, however, the concentration is preferably as high as possible in view of drying efficiency at the time of film formation. Then, the organic solvent mixed solution is heated to 70-240°C (preferably 80-220°C, more preferably 100-200°C, most preferably 100-190°C) under a pressure of 0.2MPa-30MPa. This heated solution cannot be coated as it is, and therefore needs to be cooled to a temperature below the lowest boiling point of the solvent used. In this case, the solution is typically cooled to -10 to 50°C and brought back to normal pressure. This cooling can be performed only by standing at room temperature in a high-pressure high-temperature container or a pumping system storing the triacetylcellulose solution. More preferably, the device can also be cooled using a refrigerant such as cooling water.

There is no particular limitation on the thickness of the transparent support. However, the thickness is preferably 1-300 μm, preferably 30-150 μm, particularly preferably 40-120 μm, most preferably 40-100 μm.

The light transmittance of the transparent support is preferably 80% or more, more preferably 86% or more. The turbidity of the transparent support is preferably 2.0% or less, more preferably 1.0% or less (the term "turbidity" used herein is defined as having the meaning usually given to it, and it is defined as the Science Council on Scientific terms of Ministry of The photographic terms are given in the Japanese Scientific Terms (Gakujyutsu Yougo Syu) published by Education, Culture, Sports, Science and Technology, and can be measured by a general-purpose turbidity meter). The refractive index of the transparent support is preferably 1.4-1.7. An infrared absorber or an ultraviolet absorber may be added to the transparent support. The infrared absorber is preferably added in an amount of 0.01 to 20% by weight, more preferably 0.05 to 10% by weight, based on the amount of the transparent support. Particles of an inert inorganic compound can also be added to the transparent support as a lubricant. Examples of the inorganic compound may include SiO ₂ , TiO ₂ , BaSO ₄ , CaCO ₃ , talc, and kaolin.

[Inorganic Fine Particles]

To the high refractive index layer of the antireflection film of the present invention, particles having a high refractive index for obtaining a desired refractive index may be added. As these particles, inorganic fine particles of titania, zirconia, alumina and the like can be mentioned. Among them, titanium dioxide is preferred because it has a particularly high refractive index. However, titanium dioxide has photocatalytic properties, and thus is particularly preferably used in the form of inorganic fine particles containing at least one element selected from cobalt, aluminum, and zirconium, and containing titanium dioxide as a main component. The main component refers to the component whose content (% by weight) is the highest among the components forming the granules.

The high-refractive-index layer of the present invention has a refractive index of 1.55-2.40, and it is a layer referred to simply as a so-called high-refractive-index layer or a middle-refractive-index layer. However, in this specification, this layer may be generally referred to as a high refractive index layer.

The inorganic fine particles containing titanium dioxide as a main component in the present invention have a refractive index of preferably 1.90-2.80, more preferably 2.10-2.80, most preferably 2.20-2.80.

Primary particles of inorganic fine particles containing titanium dioxide as a main component have a weight average particle diameter of preferably 1-200 nm, more preferably 5-150 nm, even more preferably 10-100 nm, particularly preferably 10-80 nm.

The particle size of each fine inorganic particle can be measured by means of light scattering or electron micrographs. The inorganic fine particles have a specific surface area of preferably 10-400 m ² /g, more preferably 20-200 m ² /g, most preferably 30-150 m ² /g.

In view of the crystal structure, the inorganic fine particles containing titanium dioxide as a main component preferably contain a component having a rutile, rutile/anatase mixed crystal, anatase or amorphous structure as a main component, particularly preferably a component having a rutile structure as a main component. Element. The main component refers to the component whose content (% by weight) is the highest among the components forming the granules.

The photocatalytic activity possessed by titanium dioxide can be suppressed by making the inorganic fine particles containing titanium dioxide as a main component contain at least one element selected from Co (cobalt), Al (aluminum) and Zr (zirconium). This can improve the weather resistance of the high refractive index layer of the present invention.

A particularly preferred element is Co (cobalt). These elements may also be preferably used in admixture of two or more thereof.

Based on the amount of Ti (titanium), the amount of Co (cobalt), Al (aluminum) or Zr (zirconium) is preferably 0.05-30% by weight, more preferably 0.1-10% by weight, and even more preferably 0.2-7% by weight, particularly preferably 0.3-5% by weight, most preferably 0.5-3% by weight.

Co (cobalt), Al (aluminum), and Zr (zirconium) can be made to exist in at least one of the inside or the surface of each inorganic fine particle containing titanium dioxide as a main component. However, they are preferably made to exist inside the fine inorganic particles containing titanium dioxide as a main component, most preferably both inside and on the surface thereof.

Co (cobalt), Al (aluminum), and Zr (zirconium) can be present (for example, blended) inside the inorganic fine particles containing titanium dioxide as a main component in various methods. For example, Ion Implantation Method (Vol.18, No.5, pp.262-268, 1998; Yasushi Aoki), and JP-A-11-263620, JP-T-11-512336 (terms used herein "JP-T" refers to the methods described in Japanese translation of published PCT patent application), EP 0335773 and JP-A-5-330825.

A process in which Co (cobalt), Al (aluminum) and Zr (zirconium) are added in a granulation method of inorganic fine particles containing titanium dioxide as a main component (for example, described in, JP-T-11-512336, EP No. 0335773 or JP-A-5-330825).

Co (cobalt), Al (aluminum) and Zr (zirconium) are also preferably present each in the form of oxides.

The inorganic fine particles containing titanium dioxide as a main component may also contain other elements depending on the desired purpose. Other elements may be included as dopants. Examples of these other elements may include Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Mg, Si, P, and S.

The inorganic fine particles containing titanium dioxide as a main component used in the present invention may be subjected to surface treatment. Its surface treatment can further reduce or destroy the photocatalytic activity of inorganic fine particles. This surface treatment is performed using inorganic, organic and organometallic compounds that reduce or destroy photocatalytic activity. Examples of the inorganic compound used for this surface treatment may include cobalt-containing inorganic compounds (such as CoO ₂ , Co ₂ O ₃ and Co ₃ O ₄ ), aluminum-containing inorganic compounds (such as Al ₂ O ₃ and Al(OH) ₃ ), Zirconium-containing inorganic compounds (such as ZrO ₂ and Zr(OH) ₄ ), silicon-containing inorganic compounds (such as SiO ₂ ), and iron-containing inorganic compounds (such as Fe ₂ O ₃ ).

Particular preference is given to cobalt-containing inorganic compounds, aluminum-containing inorganic compounds and zirconium-containing inorganic compounds. Particular preference is given to using cobalt-containing inorganic compounds, and hydroxides of Al and Zr, or combinations thereof.

Examples of organic compounds used for surface treatment may include polyhydric alcohols, alkanolamines, and stearic acid. On the other hand, examples of organometallic compounds may include silane coupling agents and titanate coupling agents. Among them, silane coupling agents are most preferable. In particular, it is preferable to perform the surface treatment with an organometallic compound represented by the following formula A and its derivatives.

Formula A:

(R ¹ ) _m -Si(OR ² ) _n

In formula A, R ¹ represents substituted or unsubstituted alkyl or aryl; R ² represents substituted or unsubstituted alkyl or acyl; and m represents 0 or an integer of 1-3, and n represents 1-4 Integer, provided the sum of m and n is 4.

In formula A, R ¹ represents a substituted or unsubstituted alkyl or aryl group. As the alkyl group, methyl, ethyl, propyl, isopropyl, hexyl, t-butyl, sec-butyl, hexyl, decyl, hexadecyl and the like can be mentioned. The number of carbon atoms of the alkyl group represented by R ¹ is 1-30, more preferably 1-16, particularly preferably 1-6. As the aryl group represented by R ¹ , there may be mentioned phenyl, naphthyl and the like, preferably phenyl.

Although there is no particular limitation on substituents, halogen atoms (such as fluorine, chlorine or bromine), hydroxyl, mercapto, carboxyl, epoxy, alkyl (such as methyl, ethyl, isopropyl, propyl or tertiary butyl), aryl (such as phenyl or naphthyl), aromatic heterocyclic group (such as furyl, pyrazolyl or pyridyl), alkoxy (such as methoxy, ethoxy, isopropoxy or hexyloxy), aryloxy (such as phenoxy), alkylthio (such as methylthio or ethylthio), arylthio (such as phenylthio), alkenyl (such as vinyl or 1-propene radical), alkoxysilyl (such as trimethoxysilyl or triethoxysilyl), acyloxy (such as acetoxy or (meth)acryloyl), alkoxycarbonyl (such as methoxycarbonyl or ethoxycarbonyl), aryloxycarbonyl (e.g. phenoxycarbonyl), carbamoyl (e.g. carbamoyl, N-methylcarbamoyl, N,N-dimethylcarbamoyl or N-methyl-N-octylcarbamoyl), acylamino (such as acetylamino, benzoylamino, acryloylamino or methacryloylamino) and the like.

Among them, a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, an alkoxysilyl group, an acyloxy group, or an acylamino group are more preferable. Particular preference is given to epoxy groups, polymerizable acyloxy groups such as (meth)acryloyl groups or polymerizable acylamino groups such as acryloylamino or methacryloylamino groups. However, these substituents may also be substituted.

R ² represents a substituted or unsubstituted alkyl or acyl group. Explanation of alkyl, acyl and substituent is the same as in R ¹ . ^R2 is preferably unsubstituted alkyl or unsubstituted acyl, particularly preferably unsubstituted alkyl.

m represents 0 or an integer of 1-3, and n represents an integer of 1-4, provided that the sum of m and n is 4. When there are a plurality of R ¹ or R ² , the plurality of R ¹ or R ² may be the same or different, respectively. m is preferably 0, 1 or 2, particularly preferably 1.

In the following, non-limiting specific examples of the compound represented by formula A of the present invention are shown.

(1)(C ₂ H ₅ O) ₄ -Si

(2)(C ₃ H ₇ O) ₄ -Si

(3)(i·C ₃ H ₇ O) ₄ -Si

(4)(CH ₃ CO ₂ ) ₄ -Si

(5)(CH ₃ CO ₂ ) ₂ -Si-(OC ₂ H ₅ ) ₂

(6) CH ₃ -Si-(OC ₂ H ₅ ) ₃

(7)C ₂ H ₅ -Si-(OC ₂ H ₅ ) ₃

(8)tC ₄ H ₉ -Si-(OCH ₃ ) ₃

(16)C ₃ F ₇ CH ₂ CH ₂ -Si-(OC ₂ H ₅ ) ₃

(17)C ₆ F ₁₃ CH ₂ CH ₂ -Si-(OC ₂ H ₅ ) ₃

(26)

NH ₂ CH ₂ CH ₂ CH ₂ -Si-(OCH ₃ ) ₃

(27)

HS-CH ₂ CH ₂ CH ₂ -Si-(OCH ₃ ) ₃

(30)

(CH ₃ O) ₃ -Si-CH ₂ CH ₂ CH ₂ CH ₂ -Si-(OCH ₃ ) ₃

(31)

(CH ₃ O) ₃ -Si-CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -Si-(OCH ₃ ) ₃

(43)

CH ₂ =CH-Si-(OCH ₃ ) ₃

Among these specific examples, (1), (12), (18), (19) and the like are particularly preferred.

Based on the total solid content of the high refractive index layer, the content of the compound of formula A is preferably 1-90% by weight, more preferably 2-80% by weight, particularly preferably 5-50% by weight.

Examples of titanate coupling agents may include metal alkoxides such as tetramethoxytitanium, tetraethoxytitanium and tetraisopropoxytitanium, and PLENACT (such as KR-TTS, KR-46B, KR-55, or KR -41B; manufactured by Ajinomoto Co., Inc.).

Examples of the organic compound used for surface treatment may include, preferably, polyols, alkanolamines, and organic compounds having other anionic groups, particularly preferably, organic compounds having carboxyl, sulfonic acid, or phosphoric acid groups.

Stearic acid, lauric acid, oleic acid, linolenic acid, linoleic acid and the like can be preferably used.

The organic compound used for surface treatment also preferably has a crosslinkable or polymerizable functional group. As crosslinkable or polymerizable functional groups, mention may be made of ethylenically unsaturated groups capable of addition/polymerization of free-radical species (e.g. (meth)acryloyl, allyl, benzene vinyl and vinyloxy), cationically polymerizable groups (such as epoxy, oxatanyl, and vinyloxy) and polycondensable groups (such as hydrolyzable silyl and N-methylol), and preferably have A group of bonded unsaturated groups.

These substances for surface treatment may be used in admixture of two or more thereof. It is particularly preferable to use an aluminum-containing inorganic compound and a zirconium-containing inorganic compound in combination.

The inorganic fine particles containing titanium dioxide as a main component of the present invention may also have a core/shell structure by surface treatment, as described in JP-A-2001-166104.

The inorganic fine particles containing titanium dioxide as a main component contained in the high refractive index layer preferably have a rice grain shape, a spherical shape, a cubic shape, a spindle shape or an indeterminate shape, particularly preferably an indeterminate shape or a spindle shape.

[Dispersant]

Inorganic fine particles containing titanium dioxide as a main component can be dispersed using a dispersant for use in the high refractive index layer of the antireflection film of the present invention.

It is particularly preferable to disperse the inorganic fine particles containing titanium dioxide as a main component of the present invention using a dispersant having an anionic group.

Anionic groups are effective groups with acidic protons such as carboxyl, sulfonic acid (and sulfo), phosphoric acid (and phosphono) and sulfonamido, and their salts, particularly preferably carboxyl, sulfonic acid and phosphoric acid groups and their salts, carboxyl groups and phosphoric acid groups are particularly preferred. It is necessary for the dispersant to contain one or more anionic groups per molecule.

In order to further improve the dispersibility of the inorganic fine particles, many anionic groups may be contained. It preferably contains an average of two or more anionic groups, more preferably five or more, particularly preferably 10 or more. As for the anionic groups contained in the dispersant, multiple types of anionic groups may also be contained in each molecule.

The dispersant also preferably contains crosslinkable or polymerizable functional groups. As crosslinkable or polymerizable functional groups, mention may be made of ethylenically unsaturated groups capable of addition/polymerization of free-radical species (e.g. (meth)acryloyl, allyl, styryl and vinyloxy), cationic polymerizable groups (such as epoxy, oxatanyl and vinyloxy) and polycondensable groups (such as hydrolyzable silyl and N-methylol), and preferably have ethylenic A group of unsaturated groups.

The dispersant for dispersing the inorganic fine particles containing titanium dioxide as a main component used in the high refractive index layer of the present invention preferably has an anionic group and a crosslinkable or polymerizable functional group, and has a crosslinkable or polymerizable functional group in the side chain. Linked or polymerizable group dispersants.

There is no particular limitation on the weight average molecular weight (Mw) of the dispersant having an anionic group and a crosslinkable or polymerizable functional group, and having a crosslinkable or polymerizable group in a side chain. Preferably 1000 or more. The weight average molecular weight (Mw) of the dispersant is more preferably 2,000-100,000, still more preferably 5,000-200,000, particularly preferably 10,000-100,000.

Anionic groups are effective groups with acidic protons such as carboxyl, sulfonic acid (and sulfo), phosphoric acid (and phosphono) and sulfonamido, and their salts, particularly preferably carboxyl, sulfonic acid and phosphoric acid groups and their salts, carboxyl groups and phosphoric acid groups are particularly preferred. The number of anionic groups per molecule contained in the dispersant is preferably two or more on average, more preferably 5 or more, particularly preferably 10 or more. As for the anionic groups contained in the dispersant, multiple types of anionic groups may also be contained in each molecule.

A dispersant having an anionic group and a crosslinkable or polymerizable functional group, and having a crosslinkable or polymerizable group in a side chain has an anionic group in a side chain or at a terminal. Polymerization of, for example, monomers containing anionic groups (e.g., (meth)acrylic acid, maleic acid, partially esterified maleic acid, itaconic acid, crotonic acid, 2-carboxyethyl (meth)acrylic acid ester, 2-sulfoethyl (meth)acrylate, and mono-2-(meth)acryloyloxyethyl phosphate), a method of allowing an acid anhydride to act on a polymer having a hydroxyl group, an amino group, etc., or others The synthesis of the polymer reaction of the method incorporates these anionic groups into the side chains.

In the dispersant having anionic groups in the side chain, based on the total number of repeating units, the composition ratio of repeating units containing anionic groups is in the range of 10-4-100 mole%, preferably 1-50 mole%, Particular preference is given to 5-20 mol %.

On the other hand, by the method of carrying out the polymerization reaction in the presence of an anionic group-containing chain transfer agent (such as thioglycolic acid), using an anionic group-containing polymerization initiator (such as V-501, manufactured by Wako Pure Chemical Industries, Ltd.) to perform a polymerization reaction, or other methods of synthesis can add an anionic group to the terminal.

Particularly preferred dispersants are those having anionic groups in side chains.

As crosslinkable or polymerizable functional groups, mention may be made of ethylenically unsaturated groups capable of addition/polymerization of free-radical species (e.g. (meth)acryloyl, allyl, styryl and vinyloxy), cationic polymerizable groups (such as epoxy, oxatanyl and vinyloxy) and polycondensable groups (such as hydrolyzable silyl and N-methylol), and preferably have ethylenic A group of unsaturated groups.

The number of crosslinkable or polymerizable functional groups per molecule contained in the dispersant is preferably two or more on average, more preferably 5 or more, particularly preferably 10 or more. As for the crosslinkable or polymerizable functional groups contained in the dispersant, various types of anionic groups may also be contained in each molecule.

In preferred dispersants for use in the present invention, examples of repeating units having ethylenically unsaturated groups in side chains include poly-1,2-butadiene and poly-1,2-isoprene structures or Repeating units of (meth)acrylate or amide. Those in which a specific residue (the R group in -COOR or -CONHR) is attached to each repeat unit are useful. Examples of specific residues (R groups) may include: -(CH ₂ ) _n -CR ₁ =CR ₂ R ₃ , -(CH ₂ O) _n -CH ₂ CR ₁ =CR ₂ R ₃ , -(CH ₂ CH ₂ O) _n -CH ₂ CR ₁ =CR ₂ R ₃ , -(CH ₂ ) _n -NH-CO-O-CH ₂ CR ₁ =CR ₂ R ₃ , -(CH ₂ ) _n -O-CO- CR ₁ =CR ₂ R ₃ and -(CH ₂ CH ₂ O) ₂ -X (wherein R ₁ -R ₃ each represent a hydrogen atom, a halogen atom, or an alkyl, aryl, or alkyl group having 1-20 carbon atoms Oxygen or aryloxy, and R ₁ and R ₂ or R ₃ can also be combined with each other to form a ring, n is an integer of 1-10, and X is a dicyclopentadiene residue). Specific examples of the ester residue may include -CH ₂ CH=CH ₂ (corresponding to allyl (meth)acrylate polymer described in JP-A-64-17047 ), -CH ₂ CH ₂ O-CH ₂ CH=CH ₂ , -CH ₂ CH ₂ OCOCH=CH ₂ , -CH ₂ CH ₂ OCOC(CH ₃ )=CH ₂ , -CH ₂ C(CH ₃ )=CH ₂ , -CH ₂ CH=CH-C ₆ H ₅ , -CH ₂ CH ₂ OCOCH=CH-C ₆ H ₅ , -CH ₂ CH ₂ -NHCOO-CH ₂ CH=CH ₂ and -CH ₂ CH ₂ OX (where X is a dicyclopentadienyl residue ). Specific examples of amido residues may include -CH ₂ CH=CH ₂ , -CH ₂ CH ₂ -Y (wherein Y is a 1-cyclohexene residue), and -CH ₂ CH ₂ -OCO-CH=CH ₂ and _{-CH2CH2 -} OCO-C( _CH3 )= _CH2 .

In a dispersant having an ethylenically unsaturated group, a free radical (a polymerization initiator free radical or a growing free radical during the polymerization of a polymerizable compound) is added to the unsaturated bond group, directly or via intermolecular Chain polymerization of polymerizable compounds leads to addition polymerization reactions. This leads to the formation of crosslinks and curing takes place. Alternatively, an atom in the molecule (eg, a hydrogen atom on a carbon atom adjacent to an unsaturated bond group) is carried away by a free radical to produce a polymer residue. They combine with each other to form crosslinks between the molecules, and curing takes place.

As described in JP-A-3-249653, monomers containing crosslinkable or polymerizable functional groups such as allyl (meth)acrylate, glycidyl (meth)acrylate and methacrylic acid Copolymerization of trialkoxysilylpropyl ester), butadiene or isoprene, or vinyl monomers with 3-chloropropionate moieties, followed by desorption For dehydrochlorination, crosslinkable or polymerizable functional groups can be added to the side chains. Alternatively, crosslinkable or polymerizable functional groups may be added synthetically or otherwise by polymer reaction (eg, polymerization of epoxy-containing vinyl monomers with carboxyl-containing polymers).

Units containing crosslinkable or polymerizable functional groups may constitute all repeating units except repeating units containing anionic groups. However, they represent 5 to 50 mol %, particularly preferably 5 to 30 mol %, of the total amount of crosslinkable or polymerizable repeat units.

Preferred dispersants of the present invention may be copolymers of suitable monomers other than monomers having crosslinkable or polymerizable functional groups and anionic groups. There are no particular limitations on these copolymerizable components. However, they are selected from various viewpoints such as dispersion stability, compatibility with other monomer components, and film-forming strength. Preferable examples thereof may include methyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, cyclohexyl (meth)acrylate, and styrene.

There is no particular limitation on the form of the preferred dispersant of the present invention. However, the dispersant is preferably a block copolymer or a random copolymer, and a random copolymer is particularly preferable in terms of cost and ease of synthesis.

Specific examples of dispersants preferably used in the present invention are shown below. Incidentally, unless otherwise specified, random copolymers are shown.

x x y y z z R Mw

P-(1) 80 20 0 0 - 40,000

P-(2) 80 20 0 0 - 110,000

P-(3) 80 20 0 0 - 10,000

P-(4) 90 10 0 0 - 40,000

P-(5) 50 50 0 0 - 40,000

P-(6) 30 20 50 CH ₂ CH ₂ CH ₃ 30,000

P-(7) 20 30 50 CH ₂ CH ₂ CH ₂ CH ₃ 50,000

P-(8) 70 20 10 CH(CH ₃ ) ₃ 60,000

150,000P-(9) 70 20 10

150,000

P-(10) 40 30 30 15,000

x/y/z represent the molar ratio

A A Mw

                                        20,000P-(11)

20,000

                        30,000P-(12)

30,000

                                        100,000P-(13)

100,000

                         20,000P-(14)

20,000

                     50,000P-(15)

50,000

P-(16) 15,000

A A Mw

    20,000P-(17)

20,000

P-(18) 25,000

    18,000P-(19)

18,000

                       20,00OP-(20)

20,00O

P-(21) 35,000

R ¹ R ² x y z Mw

P-(22) C ₄ H ₉ (n) 10 10 80 25,000

P-(23) C ₄ H ₉ (t) 10 10 80 25,000

P-(24) C ₄ H ₉ (n) 10 10 80 500,000

C₄H₉(n)    10    10    80    23,000P-(25)

C ₄ H ₉ (n) 10 10 80 23,000

C₄H₉(n)    80    10    10    30,000P-(26)

C ₄ H ₉ (n) 80 10 10 30,000

C₄H₉(n)    50    20    30    30,000P-(27)

C ₄ H ₉ (n) 50 20 30 30,000

C₄H₉(t)    10    10    80    20,000P-(28)

C ₄ H ₉ (t) 10 10 80 20,000

CH₂CH₂OH   50    10    40    20,000P-(29)

CH ₂ CH ₂ OH 50 10 40 20,000

  C₄H₉(n)    10    10    80    25,000P-(30)

C ₄ H ₉ (n) 10 10 80 25,000

P-(31) Mw=60,000

                    Mw＝10,000P-(32)

Mw=10,000

          Mw＝20,000P-(33)

Mw=20,000

P-(34)

Mw＝30,000

                                                                 

P-(35) Mw＝15,000 (block copolymer)

  (block copolymer) (block copolymer)

P-(36) Mw=8,000

P-(37) Mw=5,000

P-(38)

The amount of the dispersant used is preferably in the range of 1-50% by weight, more preferably in the range of 5-30% by weight, most preferably in the range of 5-20% by weight, based on the inorganic fine particles. Also, dispersants may be used in combination of two or more.

[High Refractive Index Layer and Method of Forming It]

The inorganic fine particles used for the high refractive index layer can be used in the form of a dispersion for forming the high refractive index layer.

As for the dispersion of inorganic fine particles, dispersion can be performed in a dispersion medium in the presence of the aforementioned dispersant.

As the dispersion medium, it is preferable to use a liquid having a boiling point of 60-170°C. Examples of the dispersion medium include water, alcohols (for example, methanol, ethanol, isopropanol, butanol, and benzyl alcohol), ketones (for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone) , esters (for example, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, ethyl formate, propyl formate, and butyl formate), aliphatic hydrocarbons (for example, hexane and cyclo hexane), halogenated hydrocarbons (e.g., methylene chloride, chloroform, and carbon tetrachloride), aromatic hydrocarbons (e.g., benzene, toluene, and xylene), amides (e.g., dimethylformamide, dimethyl acetamide and n-methylpyrrolidone), ethers (for example, diethyl ether, dioxane, and tetrahydrofuran), and ether alcohols (for example, 1-methoxy-2-propanol). Preference is given to toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol.

Particularly preferred dispersion media are methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone.

The inorganic fine particles are dispersed by a disperser. Examples of the disperser may include a sand mill (for example, a bead mill equipped with needles), a high-speed impeller mill, a pebble mill, a roll mill, a refiner, and a colloid mill. Sand mills and high-speed impeller pulverizers are particularly preferred. However, it is also possible to carry out a predispersion treatment. Examples of the dispersing machine used for the pre-dispersion treatment may include a ball mill, a three-roll mill, a kneader, and an extruder.

Inorganic fine particles are preferably reduced in size as small as possible in the dispersion medium, and have a weight average particle diameter of 1-200 nm, preferably 5-150 nm, more preferably 10-100 nm, particularly preferably 10-80 nm. A high refractive index layer can be formed by reducing the size of inorganic fine particles to 200 nm or less without impairing transparency.

The high refractive index layer used in the present invention is preferably formed as follows. In the dispersion prepared by dispersing inorganic fine particles in a dispersion medium in the aforementioned manner, preferably, a binder precursor necessary for forming a matrix (for example, an ionizing radiation-curable multifunctional monomer or a multifunctional oligomer) is also added. material), photopolymerization initiator, etc. to prepare a coating solution for forming a high refractive index layer. The resulting high-refractive-index layer-forming coating liquid is coated on a transparent support, and cured by a crosslinking reaction or a polymerization reaction of an ionizing radiation-curable compound such as a multifunctional monomer or a multifunctional oligomer.

Also, it is preferable to subject the binder and the dispersant in the high-refractive index layer to a crosslinking reaction or a polymerization reaction simultaneously with the coating of the layer or after the coating of the layer.

As for the binder in the high-refractive-index layer prepared in this way, for example, a preferred dispersant and ionizing radiation-curable multifunctional monomer or multifunctional oligomer are subjected to a crosslinking or polymerization reaction. This results in a form in which the anionic groups of the dispersant are incorporated into the binder. Also, in the binder in the high-refractive index layer, the anionic group has a function of maintaining the dispersed state of the inorganic fine particles, and the crosslinked or polymerized structure imparts film-forming ability to the binder, thereby improving the high Mechanical strength, chemical resistance and weather resistance of the refractive index layer.

The functional groups of the ionizing radiation-curable multifunctional monomers or oligomers are preferably photo-, e-beam- or radiation-polymerizable functional groups. Particular preference is given to photopolymerizable functional groups.

As the photopolymerizable functional group, unsaturated polymerizable functional groups such as (meth)acryloyl, vinyl, styryl, allyl and the like can be mentioned. Among them, a (meth)acryloyl group is preferable.

Specific examples of photopolymerizable multifunctional monomers having photopolymerizable functional groups may include:

(meth)acrylate diesters of alkylene glycols such as neopentyl glycol acrylate, 1,6-hexanediol (meth)acrylate and propylene glycol di(meth)acrylate;

(Meth)acrylate diesters of polyoxyalkylene glycols such as triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate and Polypropylene glycol di(meth)acrylate;

(meth)acrylate diesters of polyhydric alcohols such as pentaerythritol di(meth)acrylate; and (meth)acrylate diesters of ethylene oxide or propylene oxide adducts such as 2,2-bis{4-( Acryloyloxy-diethoxy)phenyl}propane and 2,2-bis{4-(acryloyloxy-polypropoxy)phenyl)propane.

Furthermore, epoxy (meth)acrylate, urethane (meth)acrylate, and polyester (meth)acrylate are also preferably used as the photopolymerizable multifunctional monomer.

Among them, esters of polyols and (meth)acrylic acid are preferred. More preferred are multifunctional monomers having 3 or more (meth)acryloyl groups per molecule. Specific examples thereof may include: trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, 1,2,4-cyclohexane tetra(meth)acrylate, Pentaerythritol triacrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, (two) pentaerythritol triacrylate, (two) pentaerythritol pentaacrylate, (two) pentaerythritol tetra(meth)acrylate ester, (di)pentaerythritol hexa(meth)acrylate, tripentaerythritol triacrylate and tripentaerythritol hexaacrylate.

The multifunctional monomers may also be used in admixture of two or more thereof.

A photopolymerization initiator is preferably used for the polymerization of the photopolymerizable multifunctional monomer. The photopolymerization initiator is preferably a radical photopolymerization initiator or a cationic photopolymerization initiator. A radical photopolymerization initiator is particularly preferable.

Examples of radical photopolymerization initiators may include: acetophenones, benzophenones, Michler's benzoyl benzoate, α-amyloxime esters, tetramethylthiuram Monosulfides and thioxanthones.

As a commercially available radical photopolymerization initiator, KAYACURE (DETX-S, BP-100, BDMK, CTX, BMS, 2-EAQ, ABQ, CPTX, EPD) manufactured by NIPPONKAYAKU Co., Ltd. may be mentioned. , ITX, QTX, BTC, MCA, etc.), Irgacure manufactured by Ciba-Geigy Japan, Ltd. (651, 184, 500, 907, 369, 1173, 2959, 4265, 4263, etc.), Esacure manufactured by Sartomer Co. (KIP100F, KB1, EB3, BP, X33, KT046, KT37, KIP150, TZT, etc.), etc.

In particular, photocleavable radical photopolymerization initiators are preferred. The photocleavable type radical photopolymerization initiator is described in SAISHIN UV KOKA GIJUTSU (Latest UVCuring Technique) (page 159, publisher; Kazuhiro Takausu, publisher; GIJUTSU JOHO KYOKAI, Co., Ltd., 1991 issue).

As a commercially available photocleavable type radical photopolymerization initiator, Irgacure (651, 184 or 907) manufactured by Ciba-Geigy Japan, Ltd., and the like can be mentioned.

The photopolymerization initiator is preferably used in an amount in the range of 0.1-15 parts by weight, more preferably in the range of 1-10 parts by weight, per 100 parts by weight of the multifunctional monomer.

In addition to photopolymerization initiators, photosensitizers can also be used. Specific examples of the photosensitizer may include n-butylamine, triethylamine, tri-n-butylphosphine, Michler's ketone, and thioxanthone.

As the commercially available photosensitizer, KAYACURE (DMBI or EPA) manufactured by NIPPON KAYAKU Co., Ltd., and the like can be mentioned.

The photopolymerization reaction is preferably performed by ultraviolet irradiation after coating and drying of the high-refractive index layer.

The high refractive index layer used in the present invention may also contain the compound represented by formula A and/or its derivative compound.

The binder in the high refractive index layer preferably further has a silanol group. Also including silanol groups in the binder will further improve the mechanical strength, chemical resistance and weather resistance of the high refractive index layer.

Silanol groups can be added to the adhesive in the following manner. For example, a compound represented by formula A having a crosslinkable or polymerizable functional group is added to a coating composition for forming a high refractive index layer. The obtained coating composition is coated on a transparent support, so that the dispersant, the multifunctional monomer or oligomer, and the compound represented by formula A undergo crosslinking reaction or polymerization reaction.

The compound represented by formula A to be added to the adhesive is particularly preferably a compound having a (meth)acryloyl group as a crosslinkable or polymerizable functional group. Examples thereof may include 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane.

The binder in the high refractive index layer also preferably has an amino group or a quaternary ammonium group.

The binder having an amino group or a quaternary ammonium group in the high refractive index layer can be formed as follows. For example, a monomer having a crosslinkable or polymerizable functional group and an amino group or a quaternary ammonium group is added to the coating composition for forming a high refractive index layer. The resulting coating composition is coated on a transparent support so that a crosslinking reaction or a polymerization reaction with a dispersant and a multifunctional monomer or a multifunctional oligomer proceeds.

The monomer having an amino group or a quaternary ammonium group functions as a dispersion aid of the inorganic fine particles in the coating composition. Also, after coating, a crosslinking reaction or a polymerization reaction with a dispersant and a multifunctional monomer or a multifunctional oligomer is performed to obtain an adhesive. This can maintain favorable dispersibility of inorganic fine particles in the high-refractive index layer, and can produce a high-refractive index layer excellent in mechanical strength, chemical resistance, and weather resistance.

As preferred monomers with amino or quaternary ammonium groups, mention may be made of N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, hydroxypropyl chloride Trimethylammonium (meth)acrylate, dimethylallyl ammonium chloride, and the like.

Based on the amount of the dispersant, the amount of monomers having amino or quaternary ammonium groups is preferably in the range of 1-40% by weight, more preferably in the range of 3-30% by weight, particularly preferably in the range of 3-20% by weight Inside. The binder is formed by cross-linking or polymerization while coating the high refractive index layer or after coating the high refractive index layer. This enables these monomers to function effectively prior to coating the high refractive index layer.

The crosslinked or polymerized binder has a structure in which the main chain of the polymer is crosslinked or polymerized. Examples of the main chain of the polymer may include polyolefin (saturated hydrocarbon), polyether, polyurea, polyurethane, polyester, polyamine, polyamide, and melamine resins. Polyolefin backbones, polyether backbones and polyurea backbones are preferred, polyolefin backbones and polyether backbones are more preferred, polyolefin backbones are most preferred.

The polyolefin backbone includes saturated hydrocarbons. The polyolefin backbone can be obtained, for example, by addition polymerization of unsaturated polymerizable groups. The polyether backbone comprises repeating units linked to each other by ether linkages (-O-). Polyether backbones can be obtained, for example, by ring-opening polymerization of epoxy groups. The polyurea backbone comprises repeating units linked to each other by urea linkages (-NH-CO-NH-). Polyurea backbones can be obtained, for example, by polycondensation reactions between isocyanate groups and amino groups. The polyurethane backbone consists of repeating units linked to each other by urethane linkages (-NH-CO-O-). The polyurethane main chain can be obtained, for example, by polycondensation reaction between isocyanate groups and hydroxyl groups (including N-methylol). The polyester backbone comprises repeating units linked to each other by ester bonds (-CO-O-). The polyester main chain can be obtained, for example, by polycondensation reaction between carboxyl groups (including acid halide groups) and hydroxyl groups (including N-methylol groups). The polyamine backbone comprises repeating units linked to each other by imino bonds (-NH-). The polyamine backbone can be obtained, for example, by ring-opening polymerization of ethyleneimine. The polyamide backbone comprises repeating units linked to each other by amido bonds (-NH-CO-). The polyamide backbone can be obtained, for example, by reaction between isocyanate groups and carboxyl groups (including acid halide groups). The melamine resin backbone can be obtained, for example, by polycondensation reaction between triazine groups (eg, melamine) and aldehydes (eg, formaldehyde). Incidentally, in the melamine resin, the main chain itself has a crosslinked or polymerized structure.

The anionic group is preferably connected to the main chain via a linking group as a side chain of the adhesive.

The linking group linking the anionic group to the main chain of the binder is preferably -CO-, -O-, an alkylene group, an arylene group, and a divalent group selected from combinations thereof. The crosslinks or polymeric structures chemically link (preferably, covalently link) two or more backbones. Cross-linked or polymeric structures preferably covalently link three or more backbones. The crosslinked or polymeric structure preferably includes CO-, -O-, -S-, nitrogen atoms, phosphorus atoms, aliphatic residues, aromatic residues, and divalent groups selected from combinations thereof.

The binder is preferably a copolymer of a repeating unit having an anionic group and another repeating unit having a crosslinked or polymerized structure. The proportion of repeating units having anionic groups in the copolymer is preferably 2-96 mol%, more preferably 4-94 mol%, most preferably 6-92 mol%. The repeating unit may have two or more anionic groups. The proportion of repeating units having a crosslinked or polymerized structure in the copolymer is preferably 4-98 mol%, more preferably 6-96 mol%, most preferably 8-94 mol%.

The repeat unit of the binder can also have both anionic groups and cross-linked or polymeric structures. The binder may also contain other repeat units (repeat units having neither anionic groups nor crosslinked or polymeric structures).

The further repeat unit is preferably a repeat unit having silanol groups, amino groups or quaternary ammonium groups.

In the repeating unit having a silanol group, the silanol group is directly connected to the main chain of the adhesive, or is connected to the main chain through a linking group. The silanol group is preferably connected as a side chain to the main chain via a linking group. The linking group linking the silanol group and the main chain of the binder is preferably -CO-, -O-, an alkylene group or an arylene group, or a divalent group selected from a combination thereof. When the binder contains a repeating unit having a silanol group, the proportion thereof is preferably 2-98 mol%, more preferably 4-96 mol%, most preferably 6-94 mol%.

In the repeating unit having an amino group or a quaternary ammonium group, the amino group or the quaternary ammonium group is directly connected to the main chain of the adhesive, or is connected to the main chain through a linking group. The amino group or quaternary ammonium group is preferably connected to the main chain as a side chain through a linking group. The amino group or quaternary ammonium group is preferably a secondary amino group, a tertiary amino group or a quaternary ammonium group, more preferably a tertiary amino group or a quaternary ammonium group. The group connected to the nitrogen atom of the secondary amino group, tertiary amino group or quaternary ammonium group is preferably an alkyl group, more preferably an alkyl group with 1-12 carbon atoms, and even more preferably an alkyl group with 1-6 carbon atoms. The counterion of the quaternary ammonium group is preferably a halide ion. The linking group linking the amino group or the quaternary ammonium group to the main chain of the adhesive is preferably -CO-, -NH-, -O-, an alkylene group, an arylene group, and a divalent group selected from combinations thereof. When the binder contains a repeating unit having an amino group or a quaternary ammonium group, the proportion thereof is preferably 0.1-32 mol%, more preferably 0.5-30 mol%, most preferably 1-28 mol%.

Incidentally, even when the repeating unit having an anionic group or the repeating unit having a crosslinked or polymerized structure contains a silanol group, and an amino group or a quaternary ammonium group, the same effect can be obtained.

The crosslinked or polymerized binder is preferably formed as follows. The coating composition for forming a high refractive index layer is coated on a transparent support. Simultaneously with coating or after coating, a crosslinking or polymerization reaction is performed.

The inorganic fine particles have the effect of controlling the refractive index of the high-refractive index layer, and the function of suppressing curing and shrinkage.

In the high refractive index layer, the inorganic fine particles are preferably dispersed as finely as possible and have a weight average particle diameter of 1 to 200 nm. The inorganic fine particles in the high refractive index layer have a weight average particle diameter of preferably 5-150 nm, more preferably 10-100 nm, particularly preferably 10-80 nm.

By reducing the size of the inorganic fine particles to 200 nm or less, it is possible to form a high refractive index layer that has no influence on transparency.

The content of the fine inorganic particles in the high refractive index layer is preferably 10 to 90% by weight, more preferably 15 to 80% by weight, particularly preferably 15 to 75% by weight, based on the weight of the high refractive index layer. Inorganic fine particles may be used in the high refractive index layer in combination of two or more.

When the antireflection film has a low-refractive-index layer on the high-refractive-index layer, the high-refractive-index layer preferably has a higher refractive index than the transparent support.

For the high-refractive index layer, ionizing radiation-curable compounds containing aromatic rings, ionizing radiation-curable compounds containing halogens other than fluorine (for example, Br, I, or Cl), compounds containing An adhesive obtained by cross-linking or polymerizing ionizing radiation-curable compounds of atoms such as S, N, or P.

In order to form a low-refractive-index layer on the high-refractive-index layer, and thereby make an anti-reflection film, the refractive index of the high-refractive index layer is preferably 1.55-2.40, more preferably 1.60-2.20, again preferably 1.65-2.10, most preferably 1.80 -2.00.

In addition to the aforementioned components (such as inorganic fine particles, polymerization initiators, and photosensitizers), resins, surfactants, antistatic agents, coupling agents, thickeners, anti-coloring agents can also be added to the high refractive index layer , colorants (pigments or dyes), defoamers, leveling agents, flame retardants, ultraviolet absorbers, infrared absorbers, tackifiers, polymerization inhibitors, antioxidants, surface modifiers, conductive metal fine particles, etc. .

However, it is also possible to make the high-refractive index layer contain particles having an average particle diameter of 0.2 to 10 μm described later, and thus it can also be used as an anti-glare layer for obtaining an anti-glare function.

The high refractive index layer can be designed to have an appropriate thickness according to the desired purpose. When the high refractive index layer is used as an optical interference layer described later, the thickness is preferably 30-200 nm, more preferably 50-170 nm, particularly preferably 60-150 nm. When the high refractive index layer is also used as a hard coat layer, the thickness is preferably 0.5-10 μm, more preferably 1-7 μm, particularly preferably 2-5 μm.

For the formation of the high refractive index layer, it is preferable to perform the crosslinking reaction or polymerization reaction of the ionizing radiation curable compound in an environment with an oxygen concentration of 10% by volume or less.

By forming the high-refractive index layer under an environment with an oxygen concentration of 10% by volume or less, the mechanical strength, chemical resistance, and weather resistance of the high-refractive index layer can be improved, and the high-refractive index layer and the phase with the high-refractive index layer can be improved. Adhesion between adjacent layers.

It can be carried out in an environment where the oxygen concentration is preferably 6% by volume or lower, more preferably 4% by volume or lower, particularly preferably 2% by volume or lower, and most preferably 1% by volume or lower. A crosslinking reaction or polymerization reaction of the ionizing radiation curable compound forms a high refractive index layer.

The oxygen concentration was adjusted to 10% by volume or less in the following manner. The air (nitrogen concentration: about 79% by volume, oxygen concentration: about 21% by volume) is preferably replaced by another gas, particularly preferably by nitrogen (flush with nitrogen).

Preferred coating solvents for the high refractive index layer are methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

The coating solvent may contain solvents other than ketone solvents. Examples may include: alcohols (e.g., methanol, ethanol, isopropanol, butanol, and benzyl alcohol), esters (e.g., methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, formic acid ethyl ester, propyl formate and butyl formate), aliphatic hydrocarbons (for example, hexane and cyclohexane), halogenated hydrocarbons (for example, methylene chloride, chloroform and carbon tetrachloride), aromatic hydrocarbons ( such as benzene, toluene, and xylene), amides (e.g., dimethylformamide, dimethylacetamide, and n-methylpyrrolidone), ethers (e.g., diethyl ether, dioxane, and tetrahydrofuran), and ether Alcohols (eg, 1-methoxy-2-propanol).

The content of the ketone solvent in the coating solvent is preferably 10% by weight or more based on the total amount of solvent contained in the coating composition. It is preferably 30% by weight or more, more preferably 60% by weight or more.

In the pencil hardness test according to JIS K5400, the strength of the high refractive index layer is preferably H or greater, more preferably 2H or greater, most preferably 3H or greater.

However, according to the Taber test of JIS K5400, it is preferable that the test piece has a small amount of abrasion before and after the test.

The high-refractive index layer preferably has lower haze when it does not contain particles imparting an anti-glare function. The turbidity is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less.

The high refractive index layer is preferably formed directly on the transparent support or formed on the transparent support through another layer.

[Low Refractive Index Layer]

The low-refractive-index layer of the antireflection film of the present invention is a cured copolymer comprising, as essential constituents, a repeating unit derived from a fluorine-containing vinyl monomer and a repeating unit each having a (meth)acryloyl group on a side chain. film formed. The copolymer-derived component preferably accounts for 70% by weight or more of the solids content of the film, more preferably 80% by weight or more, particularly preferably 90% by weight or more. The mode of adding a curing agent such as a multifunctional (meth)acrylate is not preferable from the viewpoint of simultaneously realizing a lower refractive index and a higher film hardness and compatibility.

The refractive index of the low refractive index layer is preferably 1.20-1.49, more preferably 1.20-1.45, particularly preferably 1.20-1.44.

The thickness of the low refractive index layer is preferably 50-400 nm, more preferably 50-200 nm. The haze of the low refractive index layer is preferably 3% or less, more preferably 2% or less, most preferably 1% or less. The specific strength of the low-refractive index layer in a 1-kg load pencil hardness test is preferably H or greater, more preferably 2H or greater, most preferably 3H or greater.

However, in order to enhance the antifouling performance of the antireflection film, the water contact angle of the surface is preferably 90° or greater, more preferably 95° or greater, particularly preferably 100° or greater.

Next, the copolymer used for the low refractive index layer of the present invention is described.

As fluorine-containing vinyl monomers, mention may be made of fluoroolefins (such as fluoroethylene, difluoroethylene, tetrafluoroethylene, hexafluoroethylene and hexafluoropropylene), partially or fully fluorinated alkyl groups of (meth)acrylic acid Ester derivatives (eg, BISCOAT 6FM (trade name, manufactured by Osaka Organic Chemical Industry, Ltd.) and M-2020 (trade name, manufactured by Daikin Industries, Ltd.)) and fully or partially fluorinated vinyl ethers. Perfluoroolefins are preferred. Hexafluoropropylene is particularly preferred from the viewpoints of refractive index, solubility, transparency, usability, and the like. Increasing the compositional ratio of these fluorine-containing vinyl monomers can lower the refractive index, but lowers the coating film strength. In the present invention, the fluorine-containing vinyl monomer is added so that the fluorine content of the copolymer is preferably 20-60% by weight, more preferably 25-55% by weight, particularly preferably 30-50% by weight.

The copolymer of the present invention has a (meth)acryloyl group as a repeating unit that is an essential constituent in the side chain. The method of adding (meth)acryloyl groups to the copolymer is not particularly limited. Examples thereof may include: method (1), synthesizing a polymer having a nucleophilic group such as a hydroxyl group or an amino group, and then making (meth)acrylic acid chloride, (meth)acrylic anhydride, (meth)acrylic acid, and methanesulfonic acid Mixed acid anhydride, etc. act on it; method (2), in the presence of a catalyst such as sulfuric acid, (meth)acrylic acid acts on a polymer having a nucleophilic group; method (3), making both isocyanate groups such as methyl Acryloyloxypropyl isocyanate has a compound of (meth)acryloyl group acting on the polymer with nucleophilic group; ) acrylic acid acts on it; method (5), making a compound having both an epoxy group such as glycidyl methacrylate and a (meth)acryloyl group act on a polymer having a carboxyl group; and method (6), Vinyl monomers each having a 3-chloropropionate moiety were polymerized, followed by dehydrochlorination. In the present invention, method (1) or (2) among these methods is selected for adding a (meth)acryloyl group to a polymer having a hydroxyl group.

When the composition ratio of the (meth)acryloyl group-containing repeating unit increases, the coating film strength increases, but the refractive index also increases. The proportion of the (meth)acryloyl group-containing repeating unit varies depending on the type of the repeating unit derived from the fluorine-containing vinyl monomer. In general, however, the repeating unit preferably accounts for 5-90% by weight, more preferably 30-70% by weight, particularly preferably 40-60% by weight.

As far as the copolymers used in the present invention are concerned, the differences include tackiness with the base material, Tg of the polymer (favorable for film hardness), solubility in solvents, transparency, slipperiness, and dust and stain repellency. From this point of view, other vinyl monomers other than repeating units derived from fluorine-containing vinyl monomers and repeating units each having a (meth)acryloyl group on a side chain can also be suitably copolymerized. These vinyl monomers can be used in various combinations according to the desired purpose, and based on the amount of the copolymer, their total amount is preferably in the range of 0-65 mol%, more preferably in the range of 0-40 mol%. range, particularly preferably added within the range of 0-30 mol%.

There is no particular limitation on the vinyl monomer units that can be used in combination. Examples may include: olefins (such as ethylene, propylene, isoprene, vinyl chloride, and vinylidene chloride), acrylates (such as methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, and 2- hydroxyethyl methacrylate), methacrylates (methyl methacrylate, ethyl methacrylate, butyl methacrylate and 2-hydroxyethyl methacrylate), styrene derivatives (e.g. styrene, p-hydroxy Methylstyrene and p-methoxystyrene), vinyl ethers (such as methyl vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, hydroxyethyl vinyl ether and hydroxybutyl vinyl ether) , vinyl esters (such as vinyl acetate, vinyl propionate, and vinyl cinnamate), unsaturated carboxylic acids (such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, and itaconic acid), acrylamides (such as N,N-dimethylacrylamide, N-tert-butylacrylamide and N-cyclohexylacrylamide) and methacrylamide (N,N-dimethylmethacrylamide) and acrylonitrile.

As a preferred form of the copolymer used in the present invention, the form of the following formula (1) can be mentioned:

In formula (1), L represents a linking group having 1-10 carbon atoms; m represents 0 or 1; X represents a halogen atom or a methyl group; A represents a repeating unit derived from a given vinyl monomer, and A single component or multiple components may be included; and x, y and z represent the molar percentages of their respective constituents, and these values satisfy 30≤x≤60, 5≤y≤70 and 0≤z≤65, respectively.

In formula (1), L represents a linking group with 1-10 carbon atoms, and more preferably a linking group with 1-6 carbon atoms, particularly preferably a linking group with 2-4 carbon atoms, It may have a linear or branched structure, or may have a ring structure, and may have a hetero atom selected from O, N and S.

Preferable examples thereof may include: ^* -(CH ₂ ) ₂ -O- ^** , ^* -(CH ₂ ) ₂ -NH- ^** , ^* -(CH ₂ ) ₄ -O- ^** , ^* -(CH ₂ ) ₆ -O- ^** , ^* -(CH ₂ ) ₂ -O-(CH ₂ ) ₂ -O- ^** , ^* -CONH-(CH ₂ ) ₃ -O- ^** , ^* -CH ₂ CH( OH)CH ₂ -O- ^** and ^* -CH ₂ CH ₂ OCONH(CH ₂ ) ₃ -O- ^** ( ^* represents the linking position at the polymer main chain side, ^** represents the (meth)acryloyl side connection position). m stands for 0 or 1.

In formula (1), X represents a hydrogen atom or a methyl group. Hydrogen atoms are more preferred from the viewpoint of curing reactivity.

In formula (1), A represents a repeating unit derived from a given vinyl monomer, and is not particularly limited as long as it is a constituent of a monomer copolymerizable with hexafluoropropylene. It can be appropriately selected from various viewpoints including adhesion to the base material, Tg of the polymer (favorable for film hardness), solubility in solvents, transparency, slipperiness, and dust and stain resistance. It may comprise a single vinyl monomer or a plurality of vinyl monomers depending on the desired purpose.

Preferable examples thereof may include: vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, t-butyl vinyl ether, cyclohexyl vinyl ether, isopropyl vinyl ether, hydroxyethyl vinyl ether, hydroxy Butyl vinyl ether, glycidyl vinyl ether and allyl vinyl ether; vinyl esters such as vinyl acetate, vinyl propionate and vinyl butyrate; methacrylates such as methyl (meth)acrylate , ethyl (meth)acrylate, hydroxyethyl (meth)acrylate, glycidyl methacrylate, allyl (meth)acrylate and (meth)acryloxypropyltrimethoxysilane; styrene derivatives such as styrene and p-hydroxymethylstyrene; and unsaturated carboxylic acids such as crotonic acid, maleic acid and itaconic acid, and derivatives thereof. Vinyl ether derivatives and vinyl ester derivatives are more preferred, and vinyl ether derivatives are particularly preferred.

x, y, and z represent mole percentages of their respective constituents, and represent values satisfying 30≤x≤60, 5≤y≤70, and 0≤z≤65, respectively. The cases of 35≤x≤55, 30≤y≤60 and 0≤z≤20 are preferred. Particular preference is given to the cases 40≤x≤55, 40≤y≤55 and 0≤z≤10.

As a particularly preferred form of the copolymer used in the present invention, the form of the following formula (2) may be mentioned:

In formula (2), X, x, and y are the same as described in formula (1); B represents a repeating unit derived from a given vinyl monomer, and may include a single component or multiple components; z1 and z2 represent the molar percentages of their respective constituents, and represent values satisfying 0≤z1≤65 and 0≤z2≤65 respectively; n represents an integer satisfying 2≤n≤10.

In formula (2), X, x and y represent the same ones as in formula (1), and the preferred ranges thereof are also respectively the same.

n represents an integer satisfying 2≤n≤10. Preferably 2≤n≤6, particularly preferably 2≤n≤4.

B represents a repeating unit derived from a given vinyl monomer, and may comprise a single component or multiple components. Examples thereof correspond to those listed for A in formula (1).

Z1 and Z2 represent mole percentages of their respective constituents, and represent values satisfying 0≤z1≤65 and 0≤z2≤65, respectively. They each preferably satisfy 0≤z1≤30 and 0≤z2≤10, particularly preferably 0≤z1≤10 and 0≤z2≤5.

The copolymer represented by the formula (1) or (2) can be synthesized, for example, by adding a (meth)acryloyl group to a copolymer including a hexafluoropropylene component and a hydroxyalkyl vinyl ether component by any of the methods described above.

Non-limiting preferred examples of copolymers useful in the present invention are shown below.

x x y y m m L1 x

P-1 50 0 1 *-CH ₂ CH ₂ O-** H

P-2 50 0 1 *-CH ₂ CH ₂ O-** CH ₃

P-3 45 5 1 *-CH ₂ CH ₂ O-**H

P-4 40 10 1 *-CH ₂ CH ₂ O-**H

P-5 30 20 1 *-CH ₂ CH ₂ O-**H

P-6 20 30 1 *-CH ₂ CH ₂ O-**H

P-7 50 0 0 0 0 —— H

P-8 50 0 1 *-C ₄ H ₈ O-**H

P-9 50 0 1 h

P-10 50 0 1 h

^* represents the side of the polymer main chain, ^** represents the side of the (meth)acryloyl group

x x y y m m L1 x

P-11 50 0 1 *-CH ₂ CH ₂ NH-**H

      HP-12 50 0 1

h

P-13 50 0 1 _CH3

P-14 50 0 1 _CH3

                        HP-15 50 0 1

h

                             HP-16 50 0 1

h

P-17 50 0 1 h

             CH₃ P-18 50 0 1

_CH3

P-19 50 0 1 _CH3

P-20 40 10 1 *-CH ₂ CH ₂ O-** CH ₃

^* represents the side of the polymer main chain, ^** represents the side of the (meth)acryloyl group

a a b b c c L1 A

P-21 55 45 0 *-CH ₂ CH ₂ O-** -

P-22 45 55 0 *-CH ₂ CH ₂ O-** -

P-23 50 45 5

              P-24 50 45 5

                   

P-25 50 45 5

P-26 50 40 10 *-CH ₂ CH ₂ O-**

P-27 50 40 10 *-CH ₂ CH ₂ O-**

P-28 50 40 l0 *-CH ₂ CH ₂ O-**

^* represents the side of the polymer main chain, ^** represents the side of the (meth)acryloyl group

x y y Z1 Z2 n n X B

P-29 50 40 5 5 2 H

P-30 50 35 5 10 2 H

P-31 40 40 10 10 4 CH ₃

a a b b Y Y Z

     

P-32 45 5

  

P-33 40 10

x x y y z z Rf L

P-34 60 40 0 -CH ₂ CH ₂ C ₈ F ₁₇ -n -CH ₂ CH ₂ O-

P-35 60 30 10 -CH ₂ CH ₂ C ₄ F ₈ Hn -CH ₂ CH ₂ O-

P-36 40 60 0 -CH ₂ CH ₂ C ₆ F ₁₂ H -CH ₂ CH ₂ CH ₂ CH ₂ O-

x x y z z n n Rf

P-37 50 50 0 2 -CH ₂ C ₄ F ₈ Hn

P-38 40 55 5 2 -CH ₂ C ₄ F ₈ Hn

P-39 30 70 0 4 -CH ₂ C ₈ F ₁₇ -n

P-40 60 40 0 2 -CH ₂ CH ₂ C ₈ F ₁₆ Hn

The synthesis of the copolymer used in the present invention can be carried out in the following manner. The precursors such as hydroxyl-containing polymers are synthesized by various polymerization methods as follows: solution polymerization, precipitation polymerization, suspension polymerization, bulk polymerization and emulsion polymerization. Then, a (meth)acryloyl group is added thereto by a polymerization reaction. The polymerization reaction can be carried out in known batch, semi-continuous, continuous and other types of operations.

The method of initiating polymerization includes a method including using a radical initiator, a method using light or radiation, and other methods. These polymerization methods and methods of initiating polymerization are described, for example, in Teiji Tsuruta, Polymer Synthesis Method ( KOUBUNSHI GOSEI HOUHOU ), Revised Edition, (published by The Nikkan Kogyo Shimbun, Ltd., 1971) and Experiment Method of Polymer Synthesis ( KOUBUNSHI GOUSEI NO JIKKEN HOUHOU ), by Takayuki Ootsu and Masaetsu Kinoshita, Published by Kagaku-Dojin Publishing Company, INC., 1972, pp. 124-154.

Among the above-mentioned polymerization methods, a solution polymerization method using a radical initiator is particularly preferable. Examples of the solvent used in the solution polymerization method may include various organic solvents such as ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, benzene, toluene, acetonitrile, dichloromethane, chloroform, dichloroethane, methanol, ethanol, 1-propanol, 2-propanol and 1-butanol, they can be used alone or in combination of two or more, or can also be used as a mixed solvent with water.

The polymerization temperature needs to be adjusted according to the molecular weight of the final polymer, the kind of initiator, and the like. It can be 0°C or lower to 100°C or higher. However, the polymerization reaction is preferably carried out at a temperature in the range of 50-100°C.

The reaction pressure can be appropriately selected. It is usually 1-100 kg/cm ² , particularly preferably about 1-30 kg/cm ² . The reaction time is about 5-30 hours.

The solvent used for the precipitation of the obtained polymer is preferably isopropanol, hexane, methanol or the like.

The low-refractive-index layer-forming composition of the present invention is usually in a liquid form, and contains the copolymer as an essential constituent. It is prepared by dissolving various additives and a radical polymerization initiator in a suitable solvent, if necessary. In this step, the concentration of the solid content is appropriately selected according to the desired purpose. Usually about 0.01-60% by weight, preferably 0.5-50% by weight, particularly preferably about 1%-20% by weight.

As described above, it is not necessarily beneficial to add an additive such as a hardener from the viewpoint of the film hardness of the low-refractive index layer. However, it is also possible to add a hardener such as a multifunctional (meth)acrylate compound, a multifunctional epoxy compound, a polyisocyanate compound, an aminoplast, or a polybasic acid or Its acid anhydride, or a small amount of inorganic fine particles such as silica. When they are added, they are added in an amount preferably in the range of 0-30% by weight, more preferably 0-20% by weight, particularly preferably 0-10% by weight, based on the total solid content of the low-refractive index layer film.

However, known silicone-containing or fluorine-containing antifouling agents, lubricants, and the like may also be appropriately added in order to impart features such as antifouling properties, water repellency, chemical resistance, and sliding properties. When these additives are added, they are preferably added in an amount in the range of 0-20% by weight, more preferably in the range of 0-10% by weight, particularly preferably 0%, based on the total solid content of the low-refractive index layer. -5% by weight was added.

The free radical initiator can be in the form of generating free radicals by the action of heat or in the form of generating free radicals by the action of light.

As the compound that initiates radical polymerization by the action of heat, organic or inorganic peroxides, organic azo and diazo compounds, and the like can be used.

In particular, mention may be made of organic peroxides such as benzoyl peroxide, halobenzoyl peroxide, lauroyl peroxide, acetyl peroxide, dibutyl peroxide, cumene hydroperoxide and butyl hydroperoxide oxides, inorganic peroxides such as hydrogen peroxide, ammonium persulfate and potassium persulfate; azo compounds such as 2-azo-bis-isobutyronitrile, 2-azo-bis-propionitrile and 2-azo- Di-adiponitrile, diazo compounds such as diazoaminobenzene and p-nitrobenzenediazo, and the like.

When a compound that initiates radical polymerization by photoaction is used, curing of the film is performed by active energy ray irradiation.

Examples of such radical photopolymerization initiators may include: acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, Peroxides, 2,3-dialkyldiketone compounds, disulfide compounds, fluoroamine compounds, and aromatic sulfonium compounds. Examples of acetophenone may include: 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxydimethylphenylketone, 1-hydroxycyclohexylphenylketone, 2-methylacetophenone Base-4-methylthio-2-morpholinopropiophenone and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone. Examples of benzoins may include: benzoin benzenesulfonate, benzoin tosylate, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether. Examples of benzophenones may include: benzophenone, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone, and p-chlorobenzophenone. Examples of phosphine oxides may include 2,4,6-trimethylbenzoyldiphenylphosphine oxide. Sensitizing dyes can also be preferably used together with these radical polymerization initiators.

It is necessary that the compound which initiates radical polymerization only by the action of heat or light is added in an amount capable of initiating carbon-carbon double bond polymerization. Generally, the amount is preferably 0.1 to 15% by weight, more preferably 0.5 to 10% by weight, particularly preferably 2 to 5% by weight, based on the total solid content of the low-refractive index layer-forming composition.

The solvent contained in the low-refractive index layer coating liquid composition is not particularly limited as long as it can uniformly dissolve or disperse the composition containing the fluorine-containing copolymer therein without causing precipitation. A plurality of solvents can also be used in combination. Preferable examples thereof may include: ketones (such as acetone, methyl ethyl ketone and methyl isobutyl ketone), esters (such as ethyl acetate and butyl acetate), ethers (such as tetrahydrofuran and 1,4-di oxane), alcohols (such as methanol, ethanol, isopropanol, butanol, and ethylene glycol), aromatic hydrocarbons (such as toluene and xylene), and water.

The low-refractive index layer may contain fillers (for example, inorganic fine particles and organic fine particles), silane coupling agents, lubricants (silicone compounds such as dimethyl silicone, etc.), surface-active agent etc. In particular, it is preferable to contain inorganic fine particles, a silane coupling agent, and a lubricant.

The inorganic fine particles are preferably silicon dioxide (silica) fine particles, fluorine-containing particles (magnesium fluoride, potassium fluoride, and barium fluoride particles), and the like. Particular preference is given to silicon dioxide (silica) fine particles. The weight-average particle diameter of primary particles of these inorganic fine particles is preferably 1-150 nm, more preferably 1-100 nm, most preferably 1-80 nm. These inorganic fine particles are preferably more finely dispersed in the outermost layer. The shape of the inorganic fine particles is preferably a rice grain shape, a spherical shape, a cubic shape, a spindle shape, a fibrous shape, a ring shape, or an indeterminate shape.

As a silane coupling agent, the compound represented by Formula A, and/or its derivative compound can be used. It is preferably a silane coupling agent containing a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, an alkoxysilyl group, an acyloxy group or an acylamino group. A silane coupling agent containing an epoxy group, a polymerizable acyloxy group ((meth)acryloyloxy group), or a polymerizable acylamino group (acryloylamino group or methacryloylamino group) is particularly preferred.

The compound represented by the formula A is particularly preferably a compound having a (meth)acryloyl group as a crosslinkable or polymerizable functional group. Examples thereof may include: 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane.

Lubricants are preferably dimethyl silicones and fluorochemicals having polysiloxane segments incorporated into them.

The low refractive index layer is preferably formed in the following manner. A coating composition is applied in which the fluorine-containing compound and other contained given components, if desired, are dissolved or dispersed. Simultaneously with coating or after coating, a crosslinking reaction or a polymerization reaction is performed by light irradiation, electron beam irradiation, or by heating.

Especially when the low-refractive index layer is formed by a crosslinking reaction or polymerization reaction of an ionizing radiation curable compound, the crosslinking reaction or polymerization reaction is preferably performed in an environment with an oxygen concentration of 10% by volume or less. By forming the low-refractive index layer in an environment with an oxygen concentration of 10% by volume or less, an outermost layer excellent in mechanical strength and chemical resistance can be obtained.

The oxygen concentration is preferably 6 vol% or less, the oxygen concentration is also preferably 4 vol% or less, and the oxygen concentration is particularly preferably 2 vol% or less, most preferably 1 vol% or less.

The oxygen concentration is preferably adjusted to 10% by volume or less in the following manner. The air is preferably replaced by another gas (nitrogen concentration: about 79% by volume, oxygen concentration: about 21% by volume), particularly preferably by nitrogen (flushing with nitrogen).

[hard coat]

The hard coat layer of the antireflection film of the present invention is provided on the surface of the transparent support in order to impart mechanical strength to the antireflection film. In particular, it is preferably provided between the transparent support and the high refractive index layer.

The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of an ionizing radiation curable compound. For example, it can be obtained by coating a coating composition containing ionizing radiation-curable multifunctional monomers and multifunctional oligomers on a transparent support, and performing a crosslinking reaction of the multifunctional monomers and multifunctional oligomers. Or formed by polymerization reaction.

The functional groups of the ionizing radiation-curable multifunctional monomers and multifunctional oligomers are preferably photo-, e-beam or radiation polymerizable functional groups. Among them, photopolymerizable functional groups are preferable.

As the photopolymerizable functional group, unsaturated polymerizable functional groups such as (meth)acryloyl, vinyl, styryl, allyl and the like can be mentioned. Among them, a (meth)acryloyl group is preferable.

Specific examples of the photopolymerizable multifunctional monomer having a photopolymerizable functional group may include those listed for the high refractive index layer, which are preferably polymerized using a photopolymerization initiator and a photosensitizer. The photopolymerization reaction is preferably performed by ultraviolet irradiation after coating and drying the hard coat layer.

In order to impart mechanical strength thereto, it is preferable to add inorganic fine particles having an average particle diameter of 0.001 to 0.1 μm to the hard coat layer.

Specific examples of the inorganic fine particles may include particles of silica, titania, zirconia, alumina, tin oxide, ITO, zinc oxide, and calcium carbonate. The smaller the difference in refractive index from the binder, the greater the reduction in light scattering. For this purpose, preference is given to using silicon dioxide or aluminum oxide.

The added amount of the inorganic fine particles is preferably about 5 to 50% by weight. When the amount is too large, crispness is insufficient. However, when the amount is too small, the effect of adding inorganic fine particles is insufficient.

To impart brittleness thereto according to the desired purpose, oligomers and/or polymers having a weight average molecular weight of 500 or more are preferably added to the hard coat layer.

As oligomers and polymers, there may be mentioned (meth)acrylate type, cellulose type and styrene type polymers, urethane acrylate, polyester acrylate and the like. Preferably, poly(glycidyl(meth)acrylate) and (allyl(meth)acrylate) having a functional group in a side chain, and the like can be mentioned.

Based on the total weight of the hard coat layer, the content of oligomers and/or polymers in the hard coat layer is preferably 5-50% by weight, more preferably 15-40% by weight, particularly preferably 20-30% by weight.

As mentioned above, the high refractive index layer can also be used as a hard coat layer. When the high-refractive-index layer is also used as the hard coat layer, the layer is preferably finely dispersed in the hard-coat layer with high-refractive-index inorganic fine particles by the process described in the high-refractive-index layer, thereby allowing the fine particles to be contained therein And formed.

It is also possible to make the hard coat layer further contain particles having an average particle diameter of 0.2 to 10 μm as described below, thereby also serving as an antiglare layer for obtaining an antiglare function.

The thickness of the hard coat layer can be appropriately designed according to the desired purpose. The thickness of the hard coat layer is preferably 0.2-10 μm, more preferably 1-9 μm, particularly preferably 5-8 μm.

In the pencil hardness test according to JIS K5400, the strength of the hard coat layer is preferably H or greater, more preferably 2H or greater, most preferably 3H or greater.

However, according to the Taber test of JIS K5400, it is preferable that the amount of wear of the test piece before and after the test is small.

As for the formation of the hard coat layer, when formed by a crosslinking reaction or polymerization reaction of an ionizing radiation curable compound, the crosslinking reaction or polymerization reaction is preferably performed in an environment with an oxygen concentration of 10% by volume or less. By forming the layer in an environment with an oxygen concentration of 10% by volume or less, a hard coat layer excellent in mechanical strength and chemical resistance can be formed.

In an environment with an oxygen concentration of preferably 6% by volume or lower, more preferably an oxygen concentration of 4% by volume or lower, particularly preferably an oxygen concentration of 2% by volume or lower, most preferably 1% by volume or lower, by ionizable A crosslinking reaction or polymerization reaction of the radiation curable compound forms the layer.

The oxygen concentration was adjusted to 10% by volume or less in the following manner. The air is preferably replaced by another gas (nitrogen concentration: about 79% by volume, oxygen concentration: about 21% by volume), particularly preferably by nitrogen (flushing with nitrogen).

Preferably, a coating composition for forming a hard coat layer is coated on the surface of a transparent support to form a hard coat layer.

The coating solvent is preferably a ketone solvent listed for the high refractive index layer. By using a ketone solvent, the adhesion between the surface of the transparent support (particularly, a triacetylcellulose support) and the hard coat layer is further improved.

Particularly preferred coating solvents are methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone.

The coating solvent may contain solvents other than the ketone solvents mentioned for the high refractive index layer.

In the coating solvent, the content of the ketone solvent is preferably 10% by weight or more based on the total amount of solvent contained in the coating composition. It is preferably 30% by weight or more, more preferably 60% by weight or more.

[Surface Irregularity of Anti-reflection Film]

The antireflection film used in the present invention may also have irregularities formed on the surface on the side having the high refractive index layer, thereby obtaining antiglare performance.

Anti-glare performance is related to the average surface roughness (Ra). The irregularity of the surface is preferably such that when a 1-mm area is randomly taken from a 100- ^{cm area} , the average surface roughness (Ra) is, preferably 0.01-0.4 μm, more preferably 0.03-0.3 μm, more preferably 0.05- 0.25 μm, particularly preferably 0.07-0.2 μm/1-mm ² extracted surface area.

The average surface roughness (Ra) is described in TECHNO COMPACT SERIES (6) ( Measurement/Evaluation Method of Surface Roughness ( HYOUMEN ARASANO SKUTEI · HYOUKAHOU ), author; JIROU NARA, publisher; Sougou Gijyutu Center Co., Ltd.).

The shape of the irregularities of the surface of the antireflection film used in the present invention can be evaluated by an atomic force microscope (AFM).

As a method of forming the irregularities of the surface, a known method can be used. In the present invention, a method of forming irregularities by pressing a plate having an irregular shape under high pressure on the surface of the film (for example, embossing) and making an arbitrary layer of the antireflection film contain particles serving as an antiglare layer is preferable A method of forming irregularities on the surface of an antireflection film.

For the method of forming irregularities on the surface by embossing, known processes can be used. However, it is particularly preferable to form the irregularities by the process described in JP-A-2000-329905.

When any layer of the antireflection film is made to contain particles forming the antiglare layer, the particles used for the antiglare layer are preferably particles having an average particle diameter of 0.2 to 10 μm. The average particle diameter described herein is the weight average particle diameter of secondary particles (primary particles in which particles are not flocculated).

As these particles, inorganic particles and organic particles may be mentioned. Specific examples of the inorganic particles may include particles of silica, titania, zirconia, alumina, tin oxide, ITO, zinc oxide, calcium carbonate, barium sulfate, talc, kaolin, calcium sulfate, and the like. Silica and alumina are preferred.

The organic particles are preferably resin particles. Specific examples of the resin particles may include particles made of silicone resin, melamine resin, benzoguanamine resin, polymethylmethacrylate resin, polystyrene resin, and polyvinyl difluoride. Preference is given to particles made of melamine resins, benzoguanamine resins, polymethylmethacrylate resins and polystyrene resins. Particles made of polymethylmethacrylate resins, benzoguanamine resins and polystyrene resins are particularly preferred.

In order to form irregularities, the particles used in the anti-glare layer are preferably resin particles.

The average particle diameter of the particles is preferably 0.5-7.0 μm, more preferably 1.0-5.0 μm, particularly preferably 1.5-4.0 μm.

The refractive index of the particles is preferably 1.35-1.80, more preferably 1.40-1.75, more preferably 1.45-1.75.

Particles with a smaller particle size distribution are preferred. The following equation represents an indication of the S value of the particle size distribution of the particles, and is preferably 2 or less, more preferably 1.0 or less, particularly preferably 0.7 or less.

S＝[S(0.9)-D(0.1)]/D(0.5)

D(0.1): 10% equivalent particle diameter of the integral value of volume equivalent particle diameter;

D(0.5): 50% equivalent particle diameter of the integral value of volume equivalent particle diameter; and

D(0.9): 90% equivalent particle diameter of the integral value of the volume equivalent particle diameter.

However, the refractive index of the particles is not particularly limited. However, preferably, the refractive index is approximately the same as that of the anti-glare layer (the difference in refractive index is within 0.005), or the difference is 0.02 or more.

By roughly balancing the refractive index of the particles and the refractive index of the antiglare layer, the contrast of the antireflection film mounted on the image display surface is improved.

By causing a difference between the refractive index of the particles and the refractive index of the anti-glare layer, the visibility (such as glare defects or viewing angle characteristics) when the anti-reflection film is mounted on the surface of the liquid crystal display device is improved.

When a difference is produced between the refractive index of the particles and that of the anti-glare layer, it is preferably 0.03-0.5, more preferably 0.03-0.4, particularly preferably 0.05-0.3.

Particles for imparting antiglare properties may be contained in any layer formed in the antireflection film. These particles are preferably added to a hard coat layer, a low-refractive index layer or a high-refractive index layer, particularly preferably a hard coat layer or a high-refractive index layer. It is also possible to incorporate these particles into multiple layers.

[Other layers of anti-reflection film]

In order to produce an antireflection film having more excellent antireflection properties, it is preferable to provide an intermediate refractive index layer having a refractive index between that of the high refractive index layer and that of the transparent support.

The intermediate refractive index layer is preferably prepared in the same manner as described for the high refractive index layer of the present invention. The refractive index can be adjusted by controlling the content of inorganic fine particles in the film.

In the antireflection film, layers other than the aforementioned layers may also be provided. For example, adhesive layers, barrier layers, sliding layers and antistatic layers may also be provided. Shielding is provided to block electromagnetic waves or infrared rays.

However, when the antireflection film is mounted on a liquid crystal display device, for the purpose of improving viewing angle characteristics, an undercoat layer in which particles having an average particle diameter of 0.1 to 10 μm are added may be reformed, or the particles may be added to a hard coat layer, thereby making it a light-scattering hardcoat. The average particle diameter of the particles is preferably 0.2-5.0 μm, more preferably 0.3-4.0 μm, particularly preferably 0.5-3.5 μm.

The refractive index of the particles is preferably 1.35-1.80, more preferably 1.40-1.75, again preferably 1.45-1.75.

Particles with a smaller particle size distribution are preferred. The above equation represents an indication of the S value of the particle size distribution of the particles, and is preferably 1.5 or less, more preferably 1.0 or less, particularly preferably 0.7 or less.

However, the difference in refractive index between the particles and the undercoat layer is preferably 0.02 or more. More preferably, the difference in refractive index is 0.03-0.5, more preferably, the difference in refractive index is 0.05-0.4, and particularly preferably, the difference in refractive index is 0.07-0.3.

As the particles added to the undercoat layer, inorganic particles and organic particles mentioned for the antiglare layer may be mentioned.

An undercoat layer is preferably formed between the hard coat layer and the transparent support. Moreover, it can also be used as a hard coat.

When particles having an average particle diameter of 0.1-10 [mu]m are added to the inner coat, the haze of the inner coat is preferably 3-60%. More preferably 5-50%, again preferably 7-45%, particularly preferably 10-40%.

[Method of forming anti-reflection film, etc.]

Each layer of the antireflection film can be formed by a coating method such as a metal bar coating method, a gravure coating method, a micro gravure coating method, or a die coating method. From the viewpoint of minimizing the amount of wet coating, microgravure and gravure are preferred, and thereby eliminate drying unevenness. From the standpoint of film thickness uniformity in the width direction and film thickness uniformity in the length direction over a long period of time after coating, a positive gravure method in which a support is uniformly sandwiched between a plate cylinder and an impression cylinder is particularly preferred ; or the reverse microgravure method, which is set so that the scraping pressure of the coating liquid of the blade is less likely to fluctuate in the width direction and the length direction. It is preferable from the standpoint of processing cost for forming at least two-layer antireflection film of a plurality of optical films of the present invention through the steps of single charging of a support film, forming respective optical films, and rolling up the film. When the antireflection film has a three-layer structure, it is more preferable to form three layers in a single step. This processing method can be achieved by providing multiple sets of coating stations, and drying and curing zones, and the number of these multiple sets is as many as the number of optical films in series, or there are more than the number of optical films.

Figure 2 shows an example of device configuration. Figure 2 shows such an example: the first coating station (102) included in the area from the feeder (101) to the winder (112) of the wound film that completes a process between feeding and winding , the first drying area (103), the first ultraviolet irradiation equipment (104), the second coating station (105), the second drying area (106), the second ultraviolet irradiation equipment (107), the third coating station ( 108), the third drying zone (109), the third ultraviolet irradiation equipment (110) and the post-drying zone (111). In this way, up to three layers of functional layers such as three layers of middle refractive index layer, high refractive index layer and low refractive index layer, three layers of hard coat layer, high refractive index layer and low refractive index layer can be formed in one process, or Three layers of hard coat, anti-glare layer and low refractive index layer. As other preferred forms, mention may be made of forms employing the following processing method: a method in which, if necessary, with an equipment configuration that reduces a plurality of coating stations to two, only intermediate refractive index layers are formed in one process and a two-layer high refractive index layer, and feed back the detection results of the surface condition, thickness, etc. to increase the yield, or manufacture a two-layer anti-glare anti-reflection film comprising an anti-glare layer and a low refractive index layer at low cost; and another A method in which a hard coat layer, an intermediate refractive index layer, a high refractive index layer, and a low refractive index layer are formed in one process using an apparatus configuration increased in number to four, resulting in a significant reduction in coating cost. However, the post-drying zone (111) is also used to facilitate curing when a thermosetting material is used as the main raw material, whereas it is not required when an ionizing radiation curable resin is used as the main raw material.

[Surface of anti-reflection film]

In the present invention, in the case of the antireflection film, the dynamic friction coefficient of the surface on the side having the high refractive index layer is preferably 0.25 or less in order to improve mechanical strength (eg, abrasion resistance). The coefficient of dynamic friction herein refers to when a rigid stainless steel ball with a diameter of 5 mm moves at a speed of 60 cm/min under a load of 0.98 N along the surface with a high refractive index layer side and a diameter of 5 mm The coefficient of kinetic friction between rigid stainless steel balls. It is preferably 0.17 or less, particularly preferably 0.15 or less.

However, in terms of the antireflection film, in order to improve the antifouling performance, the contact angle with water on the side having the high refractive index layer is preferably 90° or more, more preferably 95° or more, particularly preferably 100° or larger.

When the antireflection film does not have an antiglare function, haze is preferably low.

When the antireflection film has an antiglare function, its haze is preferably 0.5-50%, more preferably 1-40%, most preferably 1-30%.

[Structure of anti-reflection film]

One example of the configuration of the antireflection film of the present invention is described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a layer configuration of an antireflection film having excellent antireflection performance. This antireflection film has a layer structure of a transparent support 1 , a hard coat layer 2 , an intermediate refractive index layer 3 , a high refractive index layer 4 , and a low refractive index layer (outermost layer) 5 in this order. Transparent support 1 , intermediate refractive index layer 3 , high refractive index layer 4 , and low refractive index layer 5 each have a refractive index satisfying the following relationship.

Refractive index of high refractive index layer>Refractive index of intermediate refractive index layer>Refractive index of transparent support>Refractive index of low refractive index layer

With regard to the layer configuration shown in FIG. 1, as described in JP-A-59-50401, it is preferable that the middle refractive index layer, the high refractive index layer, and the low refractive index layer respectively satisfy the following mathematical expression (1), mathematical expression Formula (II) and mathematical expression (III), so that an anti-reflection film with more excellent anti-reflection performance can be prepared.

Mathematical expression (I):

(hλ/4)×0.7<n ₃ d ₃ <(hλ/4)×1.3

In the mathematical expression (I), h is a positive integer (usually 1, 2 or 3), _n3 is the refractive index of the intermediate refractive index layer, and _d3 is the layer thickness (nm) of the intermediate refractive index layer. λ is the wavelength (nm) of visible light, and is a value within the range of 380-680 nm. Mathematical expression (II):

(iλ/4)×0.7<n ₄ d ₄ <(iλ/4)×1.3

In the mathematical expression (II), i is a positive integer (usually 1, 2 or 3), n ₄ is the refractive index of the high refractive index layer, and d ₄ is the layer thickness (nm) of the high refractive index layer. λ is the wavelength (nm) of visible light, and is a value within the range of 380-680 nm. Mathematical expression (III):

(jλ/4)×0.7<n ₅ d ₅ <(jλ/4)×1.3

In the mathematical expression (III), j is a positive odd number (usually 1), n ₅ is the refractive index of the low refractive index layer, and d ₅ is the layer thickness (nm) of the low refractive index layer. λ is the wavelength (nm) of visible light, and is a value within the range of 380-680 nm.

With respect to the layer configuration shown in FIG. 1, it is particularly preferable that the middle refractive index layer, the high refractive index layer, and the low refractive index layer each satisfy the following Mathematical Expression (IV), Mathematical Expression (V) and Mathematical Expression (VI) .

Here, λ is 500 nm, h is 1, and j is 1.

Mathematical expression (IV):

(hλ/4)×0.80<n ₃ d ₃ <(hλ/4)×1.00

Mathematical expression (V):

(iλ/4)×0.75<n ₄ d ₄ <(iλ/4)×0.95

Mathematical expression (VI):

(jλ/4)×0.95<n ₅ d ₅ <(jλ/4)×1.05

It is preferable to make the hard coat layer, the intermediate refractive index layer and the high refractive index layer contain particles having an average particle diameter of 0.2-10 μm to prepare an antireflection film having an antiglare function.

[Protective film for polarizer]

In order to form the polarizing plate of the present invention, so that use antireflection film as the surface protection film (protective film of polarizing plate) of polarizing film, must be connected with the surface of the transparent support body opposite to the side with antireflection structure, promptly be connected with polarizing film The surface of the side is hydrophilic to improve the stickiness of the bonding surface.

As a transparent support for the antireflection film, a triacetyl cellulose film is particularly preferably used.

As a process for preparing the protective film of the polarizer of the present invention, the following two processes can be designed: (1) coating each layer (for example, high refractive index layer, hard coat layer, etc.) on one side of the transparent support that has been saponified in advance and outermost layer); and (2) coating each layer (for example, high refractive index layer, hard coat layer and outermost layer) on one side of a transparent support, and then subjecting the face connected to the polarizing film to saponification The process of processing. Among them, in the process (1), even the surface coated with the hard coat layer is hydrophilic. This makes it difficult to secure the adhesion between the support and the hard coat layer. For this reason, process (2) is preferred.

[saponification treatment]

(1) Dipping method

The immersion method is a method of immersing the antireflection film in an alkali solution under appropriate conditions so that all the surfaces of the film that are reactive with alkali are subjected to saponification treatment. This method does not require specific equipment, and thus is preferable from the viewpoint of cost. The alkaline solution is preferably an aqueous sodium hydroxide solution. The concentration is preferably 0.5-3 mol/l, particularly preferably 1-2 mol/l. The solution temperature of the alkaline solution is preferably 30-70°C, particularly preferably 40-60°C.

The combination of saponification conditions is preferably a combination of relatively moderate conditions. However, adjustments can be made depending on the material and structure of the anti-reflection film as well as the target contact angle.

After dipping the membrane in the alkali solution, preferably, the membrane is sufficiently washed with water or dipped in dilute acid to neutralize the alkali component so that no alkali component remains in the membrane.

The surface of the transparent support opposite to the surface having the antireflection layer is made hydrophilic by saponification treatment. The protective film of the polarizing plate is used in such a manner that the hydrophilic surface of the transparent support is bonded to the polarizing film.

This hydrophilic surface is effective in improving the adhesion to the adhesive layer containing polyvinyl alcohol as a main component.

In terms of saponification treatment, it is preferable that the surface of the transparent support opposite to the side having the high refractive index layer has a lower contact angle with water from the viewpoint of adhesion to the polarizing film. On the other hand, with the dipping method, the surface with the high-refractive-index layer is simultaneously destroyed by alkali, so it is important to adjust the required minimum reaction conditions. When the surface of the transparent support opposite to the side with the antireflection structure, i.e. the bonding surface of the antireflection film, the contact angle with water is used as an index of the damage of the antireflection layer by alkali, the contact angle is 20°- 50 degrees, preferably 30 degrees to 50 degrees, more preferably 40 degrees to 50 degrees, especially if the support is made of triacetyl cellulose. A contact angle of 50 degrees or more is not preferred because it brings about problems with adhesion to polarizing films. On the other hand, a contact angle of less than 20 degrees is not preferable because it causes too much damage to the antireflection film, resulting in impaired mechanical strength and light resistance.

(2) Alkaline solution coating method

As a method of avoiding damage to the antireflection film by the previous dipping method, it is preferable to use an alkali solution coating method of applying an alkali solution only on the surface opposite to the surface having the antireflection film, followed by heating, washing with water, and drying under appropriate conditions. Incidentally, coating in this case refers to an operation in which only the saponification-treated side is brought into contact with an alkali solution or the like. In this step, saponification treatment is preferably performed so that the contact angle of the adhesive surface of the antireflection film with water is 10 to 50 degrees. In addition to coating, such methods include spraying, contacting the surface with a solution-containing tape, etc., or other operations. With this method, additional equipment and steps for applying the alkaline solution are required. For this reason, this method is inferior to the impregnation method (1) from the viewpoint of cost. On the other hand, since the alkaline solution is in contact with only the saponification-treated face, the surface opposite thereto may have a layer using a material sensitive to the alkaline solution. For example, a deposited film or a sol-gel film is subjected to various influences such as corrosion, dissolution or peeling off by an alkaline solution, and therefore it is not desirable to provide such a film by dipping. However, with this coating method, the membrane does not come into contact with the solution, so it can be used without any problem.

Either of the saponification methods (1) and (2) can be carried out after the film is unwound from the roll-shaped support, and the respective layers are formed, so it can also be carried out by another series of operations after the previous antireflection film processing step . Also, by continuously performing the step of bonding the polarizing plates including the unwound support together, the polarizing plate can be formed more efficiently than the same step on a per-sheet basis.

[Polarizer]

A preferred polarizing plate of the present invention has the antireflection film of the present invention as at least one protective film of a polarizing film (protective film of a polarizing plate). With regard to the protective film of the polarizer, as mentioned above, the surface of the transparent support opposite to the side having the high refractive index layer, that is, the surface on the side connected to the polarizing film, preferably has a contact angle with water of 20 degrees to 50 degrees. In the range.

By using the antireflection film of the present invention as a protective film of a polarizer, a polarizer having excellent mechanical strength and light resistance and an antireflection function can be produced. This can greatly reduce the cost and reduce the thickness of the display.

However, by using the antireflection film of the present invention as a protective film of a polarizer, and using an optical compensation film having optical anisotropy described later as another protective film of a polarizer to prepare a polarizer, it is also possible to prepare a polarizer capable of improving The contrast ratio of the liquid crystal display device in the bright room, and the polarizer greatly expands the vertical and lateral viewing angles.

[Optical compensation layer]

The polarizing plate of the present invention may be provided with a film having an optical compensation layer, ie, an optical compensation film, on the surface of the polarizing film opposite to the surface on which the antireflection film is provided as the surface protection film.

By using a polarizing plate on which a film having an optical compensation layer (retardation layer) is provided for a liquid crystal display device, the viewing angle characteristics of the screen of the liquid crystal display device can be improved.

As the optical compensation layer, known ones can be used. However, it is preferable to use an optical compensation layer having a layer comprising a compound having a discotic structural unit and having optical anisotropy, characterized in that the angle formed between the discotic compound and the surface of the optical compensation film extends from the surface of the optical compensation film in the thickness direction to Inward variation, as described in JP-A-2001-100042.

The angle preferably increases with distance from the surface of the optical compensation film on the side connected to the polarizing film.

When using the optical compensation film as a protective film for a polarizing film, the surface on the side connected to the polarizing film is preferably subjected to saponification treatment. This treatment is preferably carried out according to the saponification treatment described above.

Also preferred is an embodiment in which the optically anisotropic layer further contains cellulose ester, another embodiment in which an alignment layer is formed between the optically anisotropic layer and a transparent support, and a transparent optical compensation layer having an optically anisotropic layer. Still another embodiment in which the support has optical negative uniaxial properties and the optical axis exists in a direction perpendicular to the surface of the transparent support, and satisfies the following conditions.

      20≤{(nx+ny)/2-nz}×d≤400

In the above conditional expression, nx: represents the refractive index along the direction of the delayed phase axis in the layer (the direction with the largest refractive index); ny: represents the refractive index along the direction of the advanced phase axis in the layer (the direction with the smallest refractive index) ; nz: represents the refractive index in the thickness direction of the layer; and d: represents the thickness of the optical compensation layer.

[image display device]

The polarizing plate with an antireflection film can be used in image display devices such as liquid crystal display devices (LCD) or electroluminescent displays (ELD). In the case of polarizers, the transparent support side of the antireflection film is attached to the image display surface.

FIG. 1 shows a preferred embodiment of using a polarizing plate using an anti-reflection film as a transparent protective film for an LCD. In Fig. 1, the transparent support (1) of the antireflection film is connected with the polarizing film (7) via an adhesive layer (6) comprising polyvinyl alcohol, and another protective film (8) of the polarizing film is bonded to the antireflective film. The surface of the polarizing film (7) opposite to the surface of the reflective film is connected through an adhesive layer (6). The polarizer has an adhesive layer (9) on the surface of another protective film (8) opposite to the surface connected to the polarizing film, and directly, or via another layer, is connected to the glass of the liquid crystal element of the liquid crystal display device, and use.

The polarizing plate using an antireflection film used in the present invention can be preferably used in twisted nematic (TN), super twisted nematic (STN), vertically aligned (VA), in-plane switching (IPS), optically compensated bending cell (OCB) ), or other modes of transmissive, reflective or semi-transmissive liquid crystal display devices.

However, when it is used for a transmissive or semi-transmissive liquid crystal display device, a commercially available brightness-enhancing film (polarization separation film having a polarized light selection layer, for example, D- BEF) can obtain a display with higher visibility.

Also, the polarizing plate can be used as a polarizing plate of a reflective liquid crystal display device or as a surface protection plate of an organic EL display to reduce reflected light from the surface and inside by using in combination with a λ/4 plate.

[Example]

The present invention will be described more specifically by way of examples below, however, the scope of the present invention is not limited thereto.

[Example 1]

(Preparation of coating solution for hard coat layer)

To 230 parts by weight of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), 76 parts by weight of ethylene oxide-modified trimethylol was added under stirring. propane triacrylate (BISCOAT360, manufactured by Osaka Organic Chemical Industry, Ltd.), 181 parts by weight of methyl ethyl ketone, 55 parts by weight of cyclohexanone, 8 parts by weight of a photopolymerization initiator (Irgacure 184, manufactured by Ciba-Geigy Japan, Ltd.) and 450 parts by weight of silica sol (MEK-ST, manufactured by NISSAN CHEMICAL INDUSTRIES, Ltd.). The resulting mixture was filtered through a filter made of polypropylene and having a pore size of 0.4 µm to prepare a coating liquid for a hard coat layer.

(Preparation of Titanium Dioxide Fine Particle Dispersion)

As the titanium dioxide fine particles, titanium dioxide fine particles containing cobalt and surface-treated with aluminum hydroxide and zirconium hydroxide (MPT-129C, manufactured by ISHIHARA SANGYO KAISHA, Ltd., TiO ₂ :Co ₃ O ₄ :Al ₂ O ₃ : ZrO ₂ =90.5:3.0:4.0:0.5 weight ratio).

To 257.1 g of these particles were added 38.6 g of the following dispersant and 704.3 g of cyclohexanone, and the resulting mixture was dispersed in a DYNO-Mill to prepare a titanium dioxide dispersion having a weight average particle diameter of 70 nm.

(Preparation of Coating Liquid for Intermediate Refractive Index Layer)

To 88.9 g of the above-mentioned titanium dioxide dispersion, 58.4 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), 3.1 g of a photopolymerization initiator were added under stirring. (Irgacure907, manufactured by Specialty Chemicals, Ltd.), 1.1 g of a photosensitizer (KAYACURE-DETX, manufactured by Nippon Kayaku Co., Ltd.), 482.4 g of methyl ethyl ketone, and 1869.8 g of cyclohexanone, in After sufficient stirring, the resulting mixture was filtered through a filter made of polypropylene with a pore size of 0.4 μm to prepare a coating liquid for an intermediate refractive index layer.

(Preparation of Coating Liquid for High Refractive Index Layer)

To 586.8 g of the aforementioned titanium dioxide dispersion, 47.9 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), 4.0 g of a photopolymerization initiator were added under stirring. (Irgacure907, manufactured by Ciba-Geigy, Japan, Ltd.), 1.3 g of a photosensitizer (KAYACURE-DETX, manufactured by Nippon Kayaku Co., Ltd.), 455.8 g of methyl ethyl ketone, and 1427.8 g of cyclohexane ketone. The resulting mixture was filtered through a filter made of polypropylene with a pore size of 0.4 µm to prepare a coating liquid for a high refractive index layer.

(Preparation of Coating Liquid for Low Refractive Index Layer)

The inventive copolymer (P-1) was dissolved in methyl isobutyl ketone at a concentration of 7% by weight. To the resulting solution was added 3% by weight of a terminal methacrylate group-containing silicone resin X-22-164C (manufactured by Shin-Etsu Chemical Co., Ltd.) on a solid content basis, and a solid content of Irgacure 907 (trade name) as a photoradical generator at a basis of 5% by weight. After sufficiently stirring, the resulting mixture was filtered through a filter made of Teflon with a pore diameter of 0.45 μm (absolute filtration diameter) to prepare a coating liquid for a low-refractive index layer.

(Preparation of anti-reflection film 1)

The coating solution for the hard coat layer was applied onto an 80 μm thick triacetylcellulose film (TD-80UF; manufactured by Fuji Photo Film Co., Ltd.) using a micro gravure coater. After drying at 90°C, it was irradiated with ultraviolet rays at an illuminance of 400 mW/ ^cm2 and an irradiation amount of 350 mJ/ ^cm2 using a 160 W/cm air-cooled metal halide lamp (manufactured by EYEGRAPHICS Co., Ltd.) while blowing nitrogen gas Flush so as to obtain an environment with an oxygen concentration of 1.0% by volume or less. As a result, the coating layer was cured to form a 4.9 μm thick hard coat layer.

A coating solution for a middle refractive index layer, a coating solution for a high refractive index layer, and a coating solution for a low refractive index layer were successively coated on the hard coat layer using a microgravure coater having 3 coating stations.

The drying conditions of the intermediate refractive index layer were adjusted to dry at 100° C. for 30 seconds. The ultraviolet irradiation curing conditions were adjusted as follows: While purging with nitrogen gas so as to obtain an environment with an oxygen concentration of 0.5% by volume or less, the illuminance was adjusted to 400 mW/cm ² and an irradiation dose of 350 mJ/cm ² .

The intermediate refractive index layer after curing had a refractive index of 1.630 and a film thickness of 67 nm.

The drying conditions of the high refractive index layer were adjusted to dry at 100° C. for 30 seconds. The ultraviolet irradiation curing conditions were adjusted as follows: While purging with nitrogen gas so as to obtain an environment with an oxygen concentration of 0.5% by volume or less, the illuminance was adjusted to 500mW/cm ² and an irradiation dose of 500mJ/cm ² .

The high refractive index layer after curing had a refractive index of 1.905 and a film thickness of 107 nm.

The drying conditions of the low-refractive index layer were adjusted to dry at 90° C. for 30 seconds. The ultraviolet irradiation curing conditions were adjusted as follows: While purging with nitrogen gas so as to obtain an environment with an oxygen concentration of 0.5% by volume or less, two 240 W/cm air-cooled metal halide lamps (manufactured by EYEGRAPHICS Co., Ltd.) were used to adjust The illuminance was 500 mW/cm ² and the irradiation amount was 1000 mJ/cm ² .

The low refractive index layer after curing had a refractive index of 1.440 and a film thickness of 83 nm.

Thus, an antireflection film 1 was produced.

(Preparation of anti-reflection film sample 2)

In addition, in the process of preparing the antireflection film sample 1, the titanium dioxide particles used for the intermediate refractive index layer and the high refractive index layer were changed to titanium dioxide fine particles surface-treated with aluminum hydroxide (TTO-55B, by ISHIHARA SANGYO KAISHA, Ltd., TiO ₂ : Al ₂ O ₃ =92.0:8.0 weight ratio) was used, thereby producing an antireflection film 2 .

(Preparation of Polarizer)

Under the conditions shown in Table 1, the obtained anti-reflection films were subjected to different degrees of saponification and washed thoroughly with water. Then, each membrane was neutralized in dilute sulfuric acid aqueous solution, followed by extensive washing with water. Thereafter, the film was sufficiently dried at 100° C. to obtain a protective film for a polarizing plate.

A 75 μm thick polyvinyl alcohol film (manufactured by Kurary Co., Ltd.) was impregnated to adsorb iodine in an aqueous solution including 1000 parts by weight of water, 7 parts by weight of iodine, and 105 parts by weight of potassium iodide. Then, the film was uniaxially stretched to 4.4 times its original length in a 4% by weight aqueous solution of boric acid, and then dried while maintaining the stretched state, thereby producing a polarizing film.

Using a polyvinyl alcohol-based adhesive as an adhesive, the triacetylcellulose side of the saponification-treated antireflection film (protective film for a polarizing plate) was bonded to one surface of the polarizing film. Also, using the same polyvinyl alcohol-based adhesive, on the other side of the polarizing film, a triacetyl cellulose film that had been subjected to the same process as Example Sample 1 in Table 1 was bonded. saponification treatment.

[Table 1] sample Anti-reflection film alkaline substance Equivalent concentration Lye temperature processing time Example sample 1 1 NaOH 1.5mol/l 55°C 100 seconds Example sample 2 1 NaOH 1.5mol/l 55°C 60 seconds Example sample 3 1 NaOH 1.5mol/l 55°C 15 seconds Example sample 4 1 NaOH 1.5mol/l 40℃ 30 seconds Example sample 5 1 NaOH 1.5mol/l 35°C 60 seconds Example sample 6 1 NaOH 2.5mol/l 70°C 15 seconds Example sample 7 1 NaOH 2.5mol/l 70°C 30 seconds Comparative example sample 1 1 NaOH 1.5mol/l 55°C 180 seconds Comparative example sample 2 1 NaOH 1.5mol/l 55°C 180 seconds

(Evaluation of anti-reflection surface of polarizing plate)

The following items were evaluated on the antireflection film side of each of the prepared polarizers. Table 2 shows the contact angle with water of the surface of each sample in Table 1 opposite to the surface having the antireflection film and the evaluation results.

(1) Steel wool scraping

Each sample was scraped back and forth 10 times with #0000 steel wool under a load of 200 g, and the degree of scratching of each sample was evaluated based on the following criteria:

◎: no scratches at all;

○: slightly scratched, but not obvious;

Δ: Scratched, but the low-refractive index layer remained; and

×: completely scratched

(2) Pencil scratch test

Conduct the pencil scratch test described in JIS K 5400. The anti-reflection film was kept at a temperature of 25° C. and a relative humidity of 60% for 2 hours. Then, using the measurement pencil specified in JIS S 6006, under a load of 500g, evaluate with n=5, the pencil with the highest hardness in which no scratches are observed at all, or one or less scratches can be observed Hardness, as the pencil hardness of the anti-reflective coating.

(3) Evaluation of weather resistance

Using a xenon arc lamp type weather resistance tester (XF mode) adjusted to outdoor average sunlight conditions through a borosilicate glass filter and a quartz filter, the relative The weather resistance test was carried out in an environment with a humidity of 50% and the irradiation time was 0 hour, 300 hours, 600 hours and 900 hours respectively.

The moisture content of each polarizer after exposure was controlled at a temperature of 25[deg.] C. and a relative humidity of 60% for 2 hours.

On the surface of each polarizing plate on the face with the antireflection film, 11 vertical cuts and 11 horizontal cuts were cut in a lattice pattern using a cutter, whereby a total of 100 squares were cut. A polyester adhesive tape (NO. 31B) manufactured by Nitto Denko Co., Ltd. was adhered thereto with pressure so that the adhesive test was repeated 3 times at the same position. Whether or not peeling occurred was observed with the naked eye, and evaluated according to the following 1 to 4 scales.

◎: Peeling was not observed at all within 100 sheets;

○: Peeling of 2 pieces or less was observed within 100 pieces;

Δ: Peeling of 3 to 10 sheets was observed within 100 sheets; and

×: Peeling of 10 or more sheets was observed in 100 sheets.

[Table 2] sample contact angle with water steel wool scraping pencil hardness Weather resistance evaluation Example sample 1 26 degrees ○ 3H ◎ Example sample 2 30 degrees ○ 3H ◎ Example sample 3 46 degrees ◎ 3H ◎ Example sample 4 46 degrees ◎ 3H ◎ Example sample 5 39 degrees ◎ 3H ◎ Example sample 6 28 degrees ○ 3H ◎ Example sample 7 29 degrees ○ 3H ◎ Comparative example sample 1 19 degrees △ h △ Comparative example sample 2 19 degrees x 2B x

Table 2 shows that the polarizing plate of the present invention can realize excellent mechanical strength and weather resistance.

[Example 2]

(Evaluation of Image Display Devices)

The TN liquid crystal display device on which the thus-prepared polarizing plate of the present invention is mounted has excellent antireflection performance and very excellent visibility.

[Example 3]

(Preparation of Polarizing Plate with Widened Viewing Angle)

The surface of the optical compensation film (Wide View Film SA-12B, manufactured by Fuji Photo Film, Co., Ltd.) having an optical compensation layer was subjected to saponification treatment by the dipping method under the same conditions as the film 1 of Example 1, Wherein the disc-shaped surface of the disc-shaped structural unit is inclined relative to the surface of the transparent support, and the angle formed between the disc-shaped surface of the disc-shaped structural unit and the surface of the transparent support varies in the thickness direction of the optically anisotropic layer. The same polyvinyl alcohol-based adhesive was used to bond the optical compensation layer of the optical compensation film instead of the saponified triacetyl cellulose in the polarizing plate 1 of Example 1. As a result, a viewing angle-enlarged polarizing plate whose both surfaces are protected by the antireflection film and the optical compensation film is formed.

(Evaluation of Image Display Devices)

A liquid crystal display device manufactured by bonding the optical compensation layer of the thus-produced polarizing plate on the glass surface on the observation side of the transmission type TN element has a higher performance in a bright room than a polarizing plate without using the optical compensation film mounted thereon. The liquid crystal display device has excellent contrast, and has very wide vertical and lateral viewing angles, more excellent anti-reflection performance, and very excellent visibility and display quality.

Meanwhile, for STN, IPS, VA or OCB mode transmissive, reflective or semi-transmissive liquid crystal display devices, the antireflection film of the present invention can be used for the polarizing plate and the Between glass cells filled with liquid crystals, or as a film on the face of the liquid crystal cell that forms the two protective films of the polarizer on the viewing side. As a result, the visibility of each mode display can be improved.

This application is based on Japanese Patent Application JP 2003-91770 filed on March 28, 2003 and Japanese Patent Application JP 2003-341323 filed on September 30, 2003, the entire contents of which are hereby incorporated herein by reference.

Claims (17)

1, a kind of preparation method of polaroid, it comprises: antireflection film and polarizing coating is bonding, described antireflection film contains transparent support and the anti-reflection structure that comprises that multilayer that refractive index is different and each layer comprise cured film, wherein the one deck at least in the multilayer that refractive index is different is that refractive index and thickness that refractive index is higher than described transparent support are the layer of 10nm-2 μ m, and described antireflection film is through bonding with described polarizing coating after the hydrophilicity-imparting treatment, makes the surface that described antireflection film and polarizing coating are bonding and the contact angle of water spend in-50 scopes of spending 20.

2, method according to claim 1, wherein said hydrophilicity-imparting treatment comprises the step that described antireflection film is immersed in the aqueous slkali that is used for saponification.

3, a kind of preparation method of polaroid, it comprises: antireflection film and polarizing coating is bonding, described antireflection film contains transparent support and the anti-reflection structure that comprises that multilayer that refractive index is different and each layer comprise cured film, wherein will with its on be formed with anti-reflection structure the surface of surperficial relative antireflection film as the surface bonding with described polarizing coating, and only with this adhesive surface through saponification handle make its with the contact angle of water in the scopes that 10 degree-50 are spent.

4, method according to claim 1, but wherein said cured film is by coating, dry and solidify the coating composition that contains at least a film forming solute and at least a solvent and obtain.

5, method according to claim 3, but wherein said cured film is by coating, dry and solidify the coating composition that contains at least a film forming solute and at least a solvent and obtain.

6, method according to claim 1, the one deck at least in the different multilayer of wherein said refractive index contains inorganic particle.

7, method according to claim 3, the one deck at least in the different multilayer of wherein said refractive index contains inorganic particle.

8, method according to claim 6, the multilayer that wherein said refractive index is different comprises that at least one refractive index is higher than the high refractive index layer and the described low-index layer that is lower than the refractive index of support of at least one refractive index of the refractive index of described support, and described high refractive index layer has the refractive index of 1.55-2.40 and contains titania and at least a inorganic particle that is selected from the element of cobalt, aluminium and zirconium.

9, method according to claim 7, the multilayer that wherein said refractive index is different comprises that at least one refractive index is higher than the high refractive index layer of refractive index of described support and the low-index layer that at least one refractive index is lower than the refractive index of described support, and described high refractive index layer has the refractive index of 1.55-2.40 and contains titania and at least a inorganic particle that is selected from the element of cobalt, aluminium and zirconium.

10, method according to claim 8, wherein said inorganic particle are had at least a compound that is selected from mineral compound, organometallics and the organic compound that reduces or destroy photocatalytic activity separately and are covered.

11, method according to claim 9, wherein said inorganic particle are had at least a compound that is selected from mineral compound, organometallics and the organic compound that reduces or destroy photocatalytic activity separately and are covered.

12, the polaroid of preparation method's preparation according to claim 1.

13, the polaroid of preparation method's preparation according to claim 3.

14, polaroid according to claim 12, wherein said polaroid comprise a plurality of surface protection films that comprise described antireflection film; The antireflection film that comprises in described a plurality of surface protection films, have an optical compensation films, optical compensating layer that contains optical anisotropic layer that provides on the one side of optical compensation films is provided for it, described with will be relative with the bonding face of polarizing coating; Described optical anisotropic layer is the layer with negative birefringence; and contain compound with disk-shaped structure unit; the dish face of described disk-shaped structure unit is with respect to the face tilt of described surface protection film, and the angle that forms between the face of the dish face of described disk-shaped structure unit and described surface protection film changes at the thickness direction of optical anisotropic layer.

15, polaroid according to claim 13, wherein said polaroid comprise a plurality of surface protection films that comprise described antireflection film; The antireflection film that comprises in described a plurality of surface protection films, have an optical compensation films, optical compensating layer that contains optical anisotropic layer that provides on the one side of optical compensation films is provided for it, described with will be relative with the bonding face of polarizing coating; Described optical anisotropic layer is the layer with negative birefringence; and contain compound with disk-shaped structure unit; the dish face of described disk-shaped structure unit is with respect to the face tilt of described surface protection film, and the angle that forms between the face of the dish face of described disk-shaped structure unit and described surface protection film changes at the thickness direction of optical anisotropic layer.

16, the liquid crystal indicator that contains polaroid as claimed in claim 12.

17, the liquid crystal indicator that contains polaroid as claimed in claim 13.

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