JP2007017946A - Antireflection film, method of forming antireflection film, polarizing plate and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antireflection film which is excellent in anti-fouling property and has compatibility between low refractive index and high pencil hardness, and also to provide a method of manufacturing a antireflection film, a polarizing plate using the antireflection film, and a liquid crystal display device. <P>SOLUTION: The reflection preventing film is constituted so that a hard coat layer is formed on a transparent supporting body, and a low refractive index layer is formed on the hard coat layer directly or through a high refractive index layer, wherein the low refractive index layer is a film consisting mainly of silicon dioxide polymer containing silica particles having voids and has a regulated ink tolerance (felt pen) of a plurality of times. Also, after the antireflection film is left as it is for 3 days under a condition of 40°C, a place where it has become impossible to wipe out an ink line by the above ink tolerance can be wiped away again for another several times. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an antireflection film, a method for producing an antireflection film, a polarizing plate and a liquid crystal display device using the antireflection film, and more specifically, an antireflection film excellent in antifouling properties and having both low refractive index and high pencil hardness, The present invention relates to a method for producing an antireflection film, a polarizing plate using the same, and a liquid crystal display device.

  From the viewpoint of antifouling properties of the antireflection film, a technique is known in which a compound having excellent antifouling properties of a fluororesin is contained in a low refractive index layer (see, for example, Patent Documents 1 to 3).

  In addition, as a technique excellent in antifouling property and low refractive index (contributing to reduction in reflectance), a technique of incorporating a fluorine-based resin in a low refractive index layer is also known (see, for example, Patent Documents 4 to 6). .

  The technique of incorporating the above-mentioned fluorine-based resin compound into the low refractive index layer cannot be written with a magic pen (in the present invention, the magic pen refers to an oil-based magic pen) by examining the type and conditions of use of the compound (magic repellent ink). It has a high resistance to magic and does not adhere to the magic ink. It exhibits a magic resistance (impossible to measure as the number of times of the present invention). In addition, the fluorine-based resin compound has a low refractive index, and has an effect of lowering the reflectance by lowering the refractive index of the low refractive index layer.

  However, the technique of incorporating a fluororesin compound in the low refractive index layer has a drawback of reducing pencil hardness. As a technique for improving pencil hardness, a technique using hollow silica fine particles and a fluorine-based organic compound is known (see, for example, Patent Documents 7 to 9). The hollow silica fine particles are excellent in terms of the low refractive index of the low refractive index layer. However, as with the above technique, the fluorine-based organic compound is intended to obtain antifouling properties (magic resistance), and has the disadvantage of reducing the pencil hardness. Have.

  The present inventor has made various studies on the above-mentioned magic resistance and pencil hardness, and obtaining a certain low refractive index, and is a film mainly composed of a silicon dioxide polymer containing fine silica particles having voids. Even if a certain range of pencil hardness and a preferred low range of refractive index are obtained and the dirt due to magic is wiped off with a soft cloth (Bencotton), and the dirt and wiping are repeated several times, it will not be wiped off. The inventors have found that an antireflection film that can be wiped off after a certain period of time can be produced.

In particular, with regard to magic resistance, conventionally, it is a problem that wiping is impossible, and it is essential that wiping is possible. The present invention, on the other hand, has found that it is possible to impart the performance that the function of wiping off can be restored after the magic cannot be wiped off, and it has never been known that the function of wiping off the magic can be restored.
JP-A-10-232301 JP 2000-66006 A JP 2002-55205 A JP 2000-159840 A JP 2001-318207 A JP 2002-53804 A JP 2002-79616 A JP 2002-317152 A JP 2002-265866 A

  In view of the above problems, an object of the present invention is to provide an antireflection film that is excellent in antifouling properties and achieves both low refractive index and high pencil hardness, a method for producing the antireflection film, a polarizing plate using the same, and a liquid crystal display device There is to do.

  The above object of the present invention is achieved by the following configurations.

1. In an antireflection film in which a hard coat layer is provided on a transparent support, and a low refractive index layer is provided directly or via a high refractive index layer on the hard coat layer,
The low refractive index layer is a film mainly composed of a silicon dioxide polymer containing silica fine particles having voids, has the following magic resistance, and the antireflection film is placed at 40 ° C. for 3 days. An anti-reflective film characterized in that when it is peeled off, the number of times that the portion that has become magic-resistant and cannot be wiped off again can be wiped up multiple times.
Magic resistance: Write a line with black oil-based magic (ZEBRA's Mackey extra fine) on the antireflection film, and wipe the line with Bencotton (Asahi Kasei) while pressing with a pressure of 1.0 kg / cm ² , If it is possible to wipe it off within 5 round trips), if it can be wiped off, write the line again with the magic at the place where the magic line was written, and check whether it can be wiped off. This operation is repeated, and the number of times that it can be written and wiped with a magic pen is taken as the value of magic resistance.

  2. 2. The antireflection film as described in 1 above, wherein the low refractive index layer contains a silicone-based nonionic surfactant having a viscosity of 1 to 500 CS at 25 ° C.

  3. 3. The antireflection film as described in 2 above, wherein a terminal of the silicone-based nonionic surfactant has a polar group.

  4). 4. The antireflection film as described in any one of 1 to 3 above, wherein the silica fine particles having voids are hollow silica fine particles.

  5. 5. The antireflection film as described in any one of 1 to 4 above, wherein the silicon dioxide polymer of the low refractive index layer is a hydrolyzate of an alkoxysilicon compound and a condensate formed by a subsequent condensation reaction. .

  6). 6. The antireflection film as described in any one of 1 to 5, wherein the transparent support is a cellulose ester film having a thickness of 20 to 60 μm.

7). In an antireflection film in which a hard coat layer is provided on a transparent support, and a low refractive index layer is provided directly or via a high refractive index layer on the hard coat layer,
The low refractive index layer is a film mainly composed of silicon dioxide polymer containing silica fine particles having voids, and contains a silicone-based nonionic surfactant having a viscosity of 1 to 500 CS at 25 ° C. An antireflection film.

  8). The antireflection film according to any one of 1 to 7 above, wherein the antireflection film is dried at a temperature of 60 to 100 ° C. after being coated with a hard coat layer, a high refractive index layer or a low refractive index layer. A method for producing a film.

  9. 8. A method for producing an antireflection film, comprising subjecting the antireflection film according to any one of 1 to 7 to a heat aging treatment at 45 ° C. or more for 24 hours or more.

  10. 8. A polarizing plate comprising the antireflection film according to any one of 1 to 7 on at least one surface.

  11. 11. A liquid crystal display device using the polarizing plate described in 10 above.

  12 12. The liquid crystal display device as described in 11 above, wherein a direct backlight is used.

  INDUSTRIAL APPLICABILITY According to the present invention, an antireflection film excellent in antifouling property and having both a low refractive index and high pencil hardness, a method for producing the antireflection film, a polarizing plate and a liquid crystal display device using the same can be provided.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

  As a result of intensive studies, the inventor has provided an antireflection film in which a hard coat layer is provided on a transparent support and a low refractive index layer is provided directly or via a high refractive index layer on the hard coat layer. The refractive index layer is a film mainly composed of silicon dioxide polymer containing silica fine particles with voids, and further contains a small amount of antifouling property and a compound (surfactant, etc.) having mobility within the layer. When the anti-reflective film is placed under a condition of 40 ° C. for 3 days, the magic-resistant portion that cannot be wiped off by the magic-proof is wiped off again by the magic-proof. It has been found that the possible number of times becomes a plurality of times and the present invention has been achieved.

  As described above, when a fluorine-based resin compound is contained in the low refractive index layer, the oil repellency and water repellency are certainly improved, but it has a drawback of reducing the pencil hardness. The present invention is a technique found in the study of a structure that can satisfy low refractive index, pencil hardness, oil repellency, and water repellency. Particularly, the location where the magic wiping cannot be wiped is 40 ° C. We found a surprising phenomenon that the number of wipings that can be wiped out again is more than once when placed under for 3 days. Furthermore, in antireflection films that exhibit such a phenomenon, both low refractive index and pencil hardness are highly compatible. It has been found that it can be done, and has achieved the object of the present invention.

  The refractive index of the low refractive index layer of the present invention is preferably in the range of 1.32 to 1.42. When the refractive index is higher than 1.42, the effect of reducing the reflectance is weak, and the refractive index can be achieved without using fine silica particles having voids. In the present invention, the refractive index of the low refractive index layer is It is preferably 1.42 or less, and more preferably in the range of 1.32 to 1.42 because magic resistance and high pencil hardness are obtained.

  The pencil hardness is preferably as high as possible, but a hardness lower than 2H can also be achieved by a method using a fluorine-based compound outside the present invention. In the present invention, a hardness higher than 2H is preferable. More preferably, it is in the range of 2H to 5H in a trade-off relationship with the refractive index of the low refractive index layer, and particularly in the range of the refractive index of the low refractive index layer of 1.32 to 1.42, a pencil. The hardness is in the range of 2H to 4H, more preferably in the range of 3 to 4H.

  Hereinafter, the present invention will be described in detail for each element.

The preferred basic layer structure of the antireflection film of the present invention is:
Transparent support-hard coat layer-low refractive index layer Transparent support-hard coat layer-high refractive index layer-low refractive index layer The high refractive index layer is a medium refractive index layer-high refractive index layer depending on the degree of refractive index. It may be divided into two layers.

  The low refractive index layer needs to be a layer mainly composed of a silicon dioxide polymer (preferably produced by a sol-gel method) containing silica fine particles having voids, and has a small amount of antifouling property. The effect of the present invention can be achieved by including a compound having mobility in the layer (in the present invention, a silicone-based nonionic surfactant).

  That is, in the antireflection film in which a hard coat layer is provided on a transparent support and a low refractive index layer is provided on the hard coat layer directly or via a high refractive index layer, the low refractive index layer has voids. A preferred embodiment for obtaining the effects of the present invention, which is a film mainly composed of a silicon dioxide polymer containing silica fine particles and contains a silicone-based nonionic surfactant having a viscosity of 1 to 500 CS at 25 ° C. It is. This is because the low refractive index layer contains silica fine particles having voids, and the antifouling compound (silicone nonionic surfactant in the present invention) is a low molecular compound having a low viscosity. It is presumed that it allows a gentle movement of the active compound in the film.

  In the present invention, the compound that can be used for imparting the above-mentioned magic resistance is preferably a silicone-based nonionic surfactant having a viscosity at 25 ° C. of 1 to 500 CS, more preferably a silicone having a viscosity of 1 to 100 CS. It is an activator of the nonionic interfacial range. Nonionic surfactant is a generic term for surfactants that do not have a group capable of dissociating into ions in an aqueous solution, but is a compound having dimethylsiloxane as a hydrophobic group, and silicone-based nonionic surfactants have hydrophilic groups particularly at the ends. A silicone compound nonionic surfactant having a polar group is preferred. The polar group is preferably an —OH group, and is a structure in which an —OH group is directly coordinated to Si in the silicone-based nonionic surfactant, and is —ROH (R is alkyl) to Si. Is more preferable.

  The silicone-based nonionic surfactant particularly preferred in the present invention is a nonionic surfactant having a hydrophobic group composed of dimethylpolysiloxane and a hydrophilic group composed of polyoxyalkylene. Among these, when a nonionic surfactant having a viscosity in the range of 1 to 500 CS is used, a portion where the magic cannot be wiped off by the magic resistance test, which is the effect of the present invention, is placed under a condition of 40 ° C. for 3 days. The number of times that the wiping can be performed again in the magic resistance test can be made a plurality of times. This is an effect that cannot be obtained by using other surfactants.

  Specific examples of these silicone-based nonionic surfactants include, for example, dimethylpolysiloxane KF-96-1000CS, KH-96-500CS, KF-96-100CS, KF-96-10CS, KF-96L-5-CS. , KF-96L-2CS (manufactured by Shin-Etsu Chemical Co., Ltd.), both-end carbinol modified silicone oil KF-6001, KF-6002 (manufactured by Shin-Etsu Chemical Co., Ltd.), both terminal hydroxy-modified silicone oil YF-3800 (manufactured by GE Toshiba Silicone), etc. Is mentioned.

  The viscosity (liquid viscosity) in the present invention is not particularly limited as long as it is verified with a standard solution for calibration of a viscometer specified in JIS Z 8809, and is of a rotary type, a vibration type or a capillary type. A viscometer can be used. As a viscometer, it can be measured with a Saybolt viscometer, a Redwood viscometer, etc., for example, Tokimec Co., Ltd., conical plate type E type viscometer, Toki Sangyo E Type Viscometer, manufactured by Tokyo Keiki Co., Ltd. B-type viscometer BL, Yamaichi Denki Co., Ltd. FVM-80A, Nametor Kogyo Viscoliner, Yamaichi Denki Co., Ltd. VISCO MATE MODEL VM-1A, and the like.

  The silicone-based nonionic surfactants conventionally used in the low refractive index layer and the hard coat layer as the leveling agent are high-viscosity polymer types. Even if these are used, the effects of the present invention can be obtained. I can't get it. In addition, the low molecular weight activator having a viscosity in the range of 1 to 500 CS preferably used in the present invention is insufficient in effect for the purpose of leveling, and a conventional high viscosity polymer for the purpose of leveling. It is preferable to use together these surfactants (made by Toray Dow Corning (formerly Nippon Unicar) FZ2222, FZ2207). Incidentally, the viscosity at 25 ° C. of the surfactant as the leveling agent is in the range of 3000 to 5000 CS.

  Further, in order to obtain a film in which the above compound can move and to obtain a certain pencil hardness, the film temperature during drying after the application of the hard coat layer, the high refractive index layer or the low refractive index layer is 100 ° C. or less, preferably It adjusts so that it may maintain at 60-100 degreeC, More preferably, 60-90 degreeC. When the temperature is lower than 60 ° C., the drying time is prolonged and the production efficiency is lowered, which is not preferable. However, drying at a temperature in the range of 60 to 100 ° C. is preferable because both the ease of movement of the compound and the production efficiency can be achieved.

  Furthermore, the antireflection film of the present invention is preferably subjected to a heat aging treatment at 45 ° C. or more for 24 hours or more. In the heat aging treatment, it is preferable to heat the roll-shaped film wound with the antireflection film in the heating aging chamber after coating and drying the antireflection layer. The temperature is preferably 45 to 100 ° C., and the heating time is preferably in the range of 24 hours to 7 days. Also in this case, it is preferable that the heating is not a high temperature and rapid heating aging, but a gentle heating aging of 50 to 80 ° C. for about 2 to 6 days.

  In this heat aging, it is particularly preferable that the film is wound into a roll after being dried under the above drying conditions.

  The transparent support preferably has a thickness of 20 to 60 [mu] m, and this thinning is required in a field where a thin and light weight is required such as a cellular phone. When the transparent support is a cellulose ester film having a film thickness of 20 to 60 μm, it is more planar than when a hard coat layer and an antireflection layer are provided on an 80 μm cellulose ester film having a normal film thickness. Problems are likely to occur.

  In particular, flatness tends to be a problem due to the heat aging. On the other hand, it is possible to obtain an antireflection film that is excellent in antifouling property for the purpose of the present invention and has both low refractive index and high pencil hardness without impairing the flatness by combining with a relatively low temperature drying condition. .

  Hereinafter, description will be made sequentially.

(Magic resistance)
Write a line with a black magic pen on the anti-reflective film, check whether the line can be removed by wiping with Ben cotton, and if wiping is possible, write a line again with a magic at the place where the magic line was written, Check if you can wipe it off. This operation is repeated, and the number of times that it can be written and wiped with a magic pen is taken as the value of magic resistance.

As the magic, an oil-based one is used, and specifically, a black oil-based magic (manufactured by ZEBRA Co., Ltd.) is preferably used. Ben cotton is a soft fabric of long fibers used for surface cleaning of precision parts and the like, and is usually white. Specifically, Ben cotton manufactured by Asahi Kasei Corporation can be preferably used. The wiping is determined by rubbing 5 times while pressing Bencotton at a pressure of 1.0 kg / cm ² and removing it.

  In order to achieve excellent antifouling properties for the purpose of the present invention and achieve both low refractive index and high pencil hardness, the magic resistance is preferably in the range of 2-50 times, more preferably in the range of 5-50 times, A range of 30 times is particularly preferred.

(Low refractive index layer)
The low refractive index layer of the present invention contains silica fine particles having voids. The term “having voids” refers to those in which microvoids are formed between the following fine particles or in the fine particles, or hollow fine particles described later, and hollow fine particles are particularly preferable. The refractive index of the low refractive index layer of the present invention is preferably in the range of 1.32 to 1.42 by using silica fine particles having voids.

<Microvoid>
As the low refractive index layer, a layer formed using inorganic fine particles as micro voids between fine particles or inside fine particles can be used. The average particle diameter of the fine particles is preferably from 0.5 to 200 mm, more preferably from 1 to 100 nm, further preferably from 3 to 70 nm, and most preferably from 5 to 40 nm. The particle diameter of the fine particles is preferably as uniform (monodispersed) as possible.

  As the inorganic fine particles, amorphous inorganic fine particles are preferable, and in the present invention, silicon dioxide, that is, silica is used.

  The microvoids in the inorganic fine particles can be formed, for example, by crosslinking silica molecules forming the particles. Crosslinking silica molecules reduces the volume and makes the particles porous. (Porous) inorganic fine particles having microvoids are prepared by a sol-gel method (described in JP-A-53-112732 and JP-B-57-9051) or a precipitation method (described in APPLIED OPTICS, 27, 3356 (1988)). Can be directly synthesized as a dispersion. Further, the powder obtained by the drying / precipitation method can be mechanically pulverized to obtain a dispersion. Commercially available porous inorganic fine particles (for example, silicon dioxide sol) may be used. The inorganic fine particles having microvoids are preferably used in a state of being dispersed in an appropriate medium in order to form a low refractive index layer. As the dispersion medium, water, alcohol (for example, methanol, ethanol, isopropyl alcohol) and ketone (for example, methyl ethyl ketone, methyl isobutyl ketone) are preferable.

  Microvoids between particles can be formed by stacking at least two fine particles. When spherical particles having the same particle diameter (completely monodispersed) are closely packed, microvoids between particles with a porosity of 26% by volume are formed. When spherical fine particles having the same particle diameter are simply filled with cubic particles, microvoids between fine particles having a porosity of 48% by volume are formed. In an actual low-refractive index layer, the particle size distribution of fine particles and intra-particle microvoids exist, so the porosity varies considerably from the above theoretical value. When the porosity is increased, the refractive index of the low refractive index layer is lowered. When microvoids are formed by stacking fine particles, the size of the microvoids can be adjusted to an appropriate value (does not scatter light and cause no problem with the strength of the low refractive index layer) by adjusting the particle size of the fine particles. You can adjust. Furthermore, by making the particle diameters of the fine particles uniform, it is possible to obtain an optically uniform low refractive index layer in which the size of microvoids between particles is uniform. As a result, the low refractive index layer is microscopically a microvoided porous film, but can be made optically or macroscopically uniform. The interparticle microvoids are preferably closed in the low refractive index layer by fine particles and a polymer. The closed air gap also has an advantage that light scattering on the surface of the low refractive index layer is less than that of an opening opened on the surface of the low refractive index layer.

  By forming the microvoids, the macroscopic refractive index of the low refractive index layer becomes lower than the sum of the refractive indexes of the components constituting the low refractive index layer. The refractive index of the layer is the sum of the refractive indices per volume of the layer components. The refractive index of the constituent component of the low refractive index layer such as fine particles or polymer is larger than 1, whereas the refractive index of air is 1.00. Therefore, a low refractive index layer having a very low refractive index can be obtained by forming microvoids.

  The low refractive index layer preferably contains the polymer in an amount of 5 to 50% by mass. The polymer has a function of adhering fine particles and maintaining the structure of a low refractive index layer including voids. The amount of the polymer used is adjusted so that the strength of the low refractive index layer can be maintained without filling the voids. The amount of the polymer is preferably 10 to 30% by mass of the total amount of the low refractive index layer. In order to adhere the fine particles with the polymer, (1) the polymer is bonded to the surface treatment agent of the fine particles, (2) the fine particles are used as a core, and a polymer shell is formed around the fine particles. It is preferable to use a polymer as the binder. The polymer to be bonded to the surface treatment agent (1) is preferably the shell polymer (2) or the binder polymer (3). The polymer (2) is preferably formed around the fine particles by a polymerization reaction before preparing the coating solution for the low refractive index layer. The polymer (3) is preferably formed by adding a monomer to the coating solution for the low refractive index layer and performing a polymerization reaction simultaneously with or after the coating of the low refractive index layer. It is preferable to carry out a combination of two or all of the above (1) to (3), and to carry out a combination of (1) and (3) or a combination of (1) to (3). Particularly preferred. (1) Surface treatment, (2) shell, and (3) binder will be described sequentially.

(1) Surface treatment It is preferable that the inorganic fine particles are subjected to a surface treatment to improve the affinity with the polymer. The surface treatment can be classified into physical surface treatment such as plasma discharge treatment and corona discharge treatment, and chemical surface treatment using a coupling agent. It is preferable to carry out only chemical surface treatment or a combination of physical surface treatment and chemical surface treatment. As the coupling agent, an organoalkoxy metal compound (eg, titanium coupling agent, silane coupling agent) is preferably used. When the fine particles are made of silicon dioxide, surface treatment with a silane coupling agent can be carried out particularly effectively. Specific examples of the silane coupling agent include methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane. Methoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropyltriacetoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxy Propyltriethoxysilane, γ- (β-glycidyloxyethoxy) propyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, γ-acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, Examples include N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane and β-cyanoethyltriethoxysilane.

  Examples of silane coupling agents having a disubstituted alkyl group with respect to silicon include dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, and γ-glycidyloxypropylmethyldiethoxysilane. Γ-glycidyloxypropylmethyldimethoxysilane, γ-glycidyloxypropylphenyldiethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldi Ethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimethyl Kishishiran, .gamma.-mercaptopropyl methyl diethoxy silane, .gamma.-aminopropyl methyl dimethoxy silane, .gamma.-aminopropyl methyl diethoxy silane, methyl vinyl dimethoxy silane, and methyl vinyl diethoxy silane.

  Among these, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, γ-acryloyloxypropyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane having a double bond in the molecule. Γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldiethoxy as those having a disubstituted alkyl group with respect to silicon Silane, methylvinyldimethoxysilane and methylvinyldiethoxysilane are preferred, γ-acryloyloxypropyltrimethoxysilane and γ-methacryloyloxy Propyltrimethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane and γ-methacryloyloxypropylmethyldiethoxysilane are particularly preferred.

  Two or more coupling agents may be used in combination. In addition to the silane coupling agents shown above, other silane couplings may be used. Other silane coupling agents include alkyl esters of orthosilicate (eg, methyl orthosilicate, ethyl orthosilicate, n-propyl orthosilicate, i-propyl orthosilicate, n-butyl orthosilicate, sec-butyl orthosilicate, orthosilicate). Acid t-butyl) and its hydrolyzate. The surface treatment with the coupling agent can be carried out by adding the coupling agent to the fine particle dispersion and allowing the dispersion to stand at a temperature from room temperature to 60 ° C. for several hours to 10 days. In order to accelerate the surface treatment reaction, inorganic acids (for example, sulfuric acid, hydrochloric acid, nitric acid, chromic acid, hypochlorous acid, boric acid, orthosilicic acid, phosphoric acid, carbonic acid), organic acids (for example, acetic acid, polyacrylic acid, Benzenesulfonic acid, phenol, polyglutamic acid), or salts thereof (eg, metal salts, ammonium salts) may be added to the dispersion.

(2) Shell The polymer forming the shell is preferably a polymer having a saturated hydrocarbon as the main chain. A polymer containing a fluorine atom in the main chain or side chain is preferred, and a polymer containing a fluorine atom in the side chain is more preferred. Polyacrylic acid esters or polymethacrylic acid esters are preferred, and esters of fluorine-substituted alcohols with polyacrylic acid or polymethacrylic acid are most preferred. The refractive index of the shell polymer decreases as the content of fluorine atoms in the polymer increases. In order to lower the refractive index of the low refractive index layer, the shell polymer preferably contains 35 to 80% by mass of fluorine atoms, and more preferably contains 45 to 75% by mass of fluorine atoms. The polymer containing a fluorine atom is preferably synthesized by a polymerization reaction of an ethylenically unsaturated monomer containing a fluorine atom. Examples of ethylenically unsaturated monomers containing fluorine atoms include fluoroolefins (eg, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole), Mention may be made of esters of fluorinated vinyl ethers and fluorine-substituted alcohols with acrylic acid or methacrylic acid.

  The polymer forming the shell may be a copolymer composed of a repeating unit containing a fluorine atom and a repeating unit not containing a fluorine atom. The repeating unit containing no fluorine atom is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer containing no fluorine atom. Examples of ethylenically unsaturated monomers that do not contain fluorine atoms include olefins (eg, ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride), acrylic acid esters (eg, methyl acrylate, ethyl acrylate, acrylic acid 2- Ethyl hexyl), methacrylic acid esters (for example, methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate), styrene and its derivatives (for example, styrene, divinylbenzene, vinyltoluene, α-methylstyrene), vinyl ether ( For example, methyl vinyl ether), vinyl esters (for example, vinyl acetate, vinyl propionate, vinyl cinnamate), acrylamide (for example, N-tertbutylacrylamide, N-cyclohexylacrylic) Amides), methacrylamide and acrylonitrile.

  When the binder polymer (3) described later is used in combination, a crosslinkable functional group may be introduced into the shell polymer to chemically bond the shell polymer and the binder polymer by crosslinking. The shell polymer may have crystallinity. When the glass transition temperature (Tg) of the shell polymer is higher than the temperature at the time of forming the low refractive index layer, it is easy to maintain microvoids in the low refractive index layer. However, if Tg is higher than the temperature at which the low refractive index layer is formed, the fine particles are not fused, and the low refractive index layer may not be formed as a continuous layer (resulting in a decrease in strength). In that case, it is desirable to use a binder polymer (3) described later in combination, and form the low refractive index layer as a continuous layer with the binder polymer. By forming a polymer shell around the fine particles, core-shell fine particles are obtained. The core-shell fine particles preferably contain 5 to 90% by volume of a core composed of inorganic fine particles, and more preferably 15 to 80% by volume. Two or more kinds of core-shell fine particles may be used in combination. Further, inorganic fine particles having no shell and core-shell particles may be used in combination.

(3) Binder The low refractive index layer of the present invention can be used in combination with a binder polymer other than the silicon dioxide polymer according to the present invention as long as the effects of the present invention are not impaired. Alternatively, a polymer having a polyether as a main chain is preferable, and a polymer having a saturated hydrocarbon as a main chain is more preferable. The binder polymer is preferably crosslinked. The polymer having a saturated hydrocarbon as the main chain is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer. In order to obtain a crosslinked binder polymer, it is preferable to use a monomer having two or more ethylenically unsaturated groups. Examples of monomers having two or more ethylenically unsaturated groups include esters of polyhydric alcohols and (meth) acrylic acid (for example, ethylene glycol di (meth) acrylate, 1,4-dichlorohexane diacrylate, pentaerythritol). Tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate), vinylbenzene and its derivatives For example, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloyl ethyl ester, 1,4-divinylcyclohexanone), vinyl sulfone (eg, divinyl sulfone), acrylamide (eg, methylene bisacrylamide) and methacrylamide Can be mentioned. The polymer having a polyether as the main chain is preferably synthesized by a ring-opening polymerization reaction of a polyfunctional epoxy compound. Instead of or in addition to the monomer having two or more ethylenically unsaturated groups, a crosslinked structure may be introduced into the binder polymer by the reaction of a crosslinkable group. Examples of crosslinkable functional groups include isocyanate groups, epoxy groups, aziridine groups, oxazoline groups, aldehyde groups, carbonyl groups, hydrazine groups, carboxyl groups, methylol groups, and active methylene groups. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane can also be used as a monomer for introducing a crosslinked structure. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. The cross-linking group is not limited to the above compound, and may be one that exhibits reactivity as a result of decomposition of the functional group. As the polymerization initiator used for the polymerization reaction and the crosslinking reaction of the binder polymer, a thermal polymerization initiator or a photopolymerization initiator is used, and the photopolymerization initiator is more preferable. Examples of photopolymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds , Fluoroamine compounds and aromatic sulfoniums. Examples of acetophenones include 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxydimethylphenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-4-methylthio-2-morpholinopropiophenone and 2 -Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone. Examples of benzoins include benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether. Examples of benzophenones include benzophenone, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone and p-chlorobenzophenone. Examples of phosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

  The binder polymer is preferably formed by adding a monomer to the coating solution for the low refractive index layer, and at the same time as or after the coating of the low refractive index layer, by a polymerization reaction (further crosslinking reaction if necessary). Even if a small amount of polymer (for example, polyvinyl alcohol, polyoxyethylene, polymethyl methacrylate, polymethyl acrylate, diacetyl cellulose, triacetyl cellulose, nitrocellulose, polyester, alkyd resin) is added to the coating solution for the low refractive index layer Good.

<Hollow particles>
It is particularly preferable that the low refractive index layer contains the following hollow fine particles.

  The hollow fine particles referred to here are (1) composite particles composed of porous particles and a coating layer provided on the surface of the porous particles, or (2) hollow inside, and the content is a solvent, gas or Cavity particles filled with a porous material. In addition, the coating liquid for low refractive index layers should just contain either (1) composite particle | grains or (2) cavity particle | grains, and may contain both.

  The hollow particles are particles having cavities inside, and the cavities are surrounded by particle walls. The cavity is filled with contents such as a solvent, a gas, or a porous material used at the time of preparation. It is desirable that the average particle size of such inorganic fine particles is in the range of 5 to 300 nm, preferably 10 to 200 nm. The inorganic fine particles used are appropriately selected according to the thickness of the transparent film to be formed, and may be in the range of 2/3 to 1/10 of the film thickness of the formed transparent film such as a low refractive index layer. desirable. These inorganic fine particles are preferably used in a state of being dispersed in an appropriate medium in order to form a low refractive index layer. As the dispersion medium, water, alcohol (for example, methanol, ethanol, isopropyl alcohol), ketone (for example, methyl ethyl ketone, methyl isobutyl ketone), and ketone alcohol (for example, diacetone alcohol) are preferable.

  The thickness of the coating layer of the composite particles or the thickness of the particle walls of the hollow particles is desirably in the range of 1 to 20 nm, preferably 2 to 15 nm. In the case of composite particles, when the thickness of the coating layer is less than 1 nm, the particles may not be completely covered, and the low refractive index effect may not be sufficiently obtained. On the other hand, when the thickness of the coating layer exceeds 20 nm, the porosity (pore volume) of the composite particles may be lowered, and the low refractive index effect may not be sufficiently obtained. In the case of hollow particles, when the particle wall thickness is less than 1 nm, the particle shape may not be maintained, and even if the thickness exceeds 20 nm, the effect of low refractive index may not be sufficiently exhibited. is there.

The coating layer of the composite particle or the particle wall of the hollow particle contains silica as a main component. The coating layer of the composite particle or the particle wall of the hollow particle may contain a component other than silica, specifically, Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO _2. and _{CeO 2, P 2 O 3,} Sb 2 O 3, MoO 3, ZnO 2, WO 3 and the like. Examples of the porous particles constituting the composite particles include those made of silica, those made of silica and an inorganic compound other than silica, and those made of CaF ₂ , NaF, NaAlF ₆ , MgF, and the like. Among these, porous particles made of a composite oxide of silica and an inorganic compound other than silica are particularly preferable. Examples of inorganic compounds other than silica include Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , P ₂ O ₃ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ , WO _{3 and the} like. 1 type or 2 types or more can be mentioned. In such porous particles, the molar ratio MOX / SiO ₂ when the silica is represented by SiO ₂ and the inorganic compound other than silica is represented by oxide (MOX) is 0.0001 to 1.0, preferably It is desirable to be in the range of 0.001 to 0.3. It is difficult to obtain a porous particle having a molar ratio MOX / SiO ₂ of less than 0.0001, and even if it is obtained, conductivity is not exhibited. On the other hand, if the molar ratio MOX / SiO _{2 of} the porous particles exceeds 1.0, the ratio of silica decreases, so that particles having a small pore volume and a low refractive index may not be obtained.

  The pore volume of such porous particles is desirably in the range of 0.1 to 1.5 ml / g, preferably 0.2 to 1.5 ml / g. If the pore volume is less than 0.1 ml / g, particles having a sufficiently reduced refractive index cannot be obtained. If the pore volume exceeds 1.5 ml / g, the strength of the fine particles is lowered, and the strength of the resulting coating may be lowered. is there.

  Incidentally, the pore volume of such porous particles can be determined by a mercury intrusion method. Examples of the contents of the hollow particles include a solvent, a gas, and a porous substance used at the time of preparing the particles. The solvent may contain an unreacted particle precursor used when preparing the hollow particles, the catalyst used, and the like. Moreover, what consists of the compound illustrated by the said porous particle as a porous substance is mentioned. These contents may be composed of a single component or may be a mixture of a plurality of components.

  As a method for producing such inorganic fine particles, for example, the method for preparing composite oxide colloidal particles disclosed in paragraphs [0010] to [0033] of JP-A-7-133105 is suitably employed. Specifically, when the composite particles are composed of silica and an inorganic compound other than silica, the inorganic compound particles are produced from the following first to third steps.

First Step: Preparation of Porous Particle Precursor In the first step, an alkali aqueous solution of a silica raw material and an inorganic compound raw material other than silica is separately prepared in advance, or a silica raw material and an inorganic compound raw material other than silica are prepared in advance. A mixed aqueous solution is prepared, and this aqueous solution is gradually added to an aqueous alkaline solution having a pH of 10 or more while stirring according to the composite ratio of the target composite oxide to prepare a porous particle precursor.

  As the silica raw material, alkali metal, ammonium or organic base silicate is used. As an alkali metal silicate, sodium silicate (water glass) or potassium silicate is used. Examples of the organic base include quaternary ammonium salts such as tetraethylammonium salt, and amines such as monoethanolamine, diethanolamine, and triethanolamine. The ammonium silicate or the organic base silicate includes an alkaline solution obtained by adding ammonia, a quaternary ammonium hydroxide, an amine compound or the like to a silicic acid solution.

  Moreover, the alkali-soluble conductive compound is used as a raw material for inorganic compounds other than silica.

Although the pH value of the mixed aqueous solution changes simultaneously with the addition of these aqueous solutions, an operation for controlling the pH value within a predetermined range is not particularly required. The aqueous solution finally has a pH value determined by the type of inorganic oxide and the mixing ratio thereof. There is no restriction | limiting in particular in the addition rate of the aqueous solution at this time. Further, in the production of composite oxide particles, a dispersion of seed particles can be used as a starting material. The seed particles are not particularly limited, but inorganic oxides such as SiO ₂ , Al ₂ O ₃ , TiO ₂ or ZrO ₂ or fine particles of these composite oxides are used. Usually, these sols are used. I can do it. Furthermore, the porous particle precursor dispersion obtained by the above production method may be used as a seed particle dispersion. When the seed particle dispersion is used, the pH of the seed particle dispersion is adjusted to 10 or more, and then the aqueous solution of the compound is added to the above-described alkaline aqueous solution while stirring. Also in this case, it is not always necessary to control the pH of the dispersion. In this way, when seed particles are used, it is easy to control the particle size of the porous particles to be prepared, and particles with uniform particle sizes can be obtained.

  The silica raw material and inorganic compound raw material described above have high solubility on the alkali side. However, when both are mixed in this highly soluble pH region, the solubility of oxo acid ions such as silicate ions and aluminate ions decreases, and these composites precipitate and grow into fine particles, or seed particles. Particle growth occurs by depositing on the top. Therefore, it is not always necessary to perform pH control as in the conventional method for precipitation and growth of fine particles.

The composite ratio of silica and inorganic compound other than silica in the first step is that the inorganic compound relative to silica is converted to oxide (MOx), and the molar ratio of MOx / SiO ₂ is 0.05 to 2.0, preferably It is desirable to be within the range of 0.2 to 2.0. Within this range, the pore volume of the porous particles increases as the proportion of silica decreases. However, even when the molar ratio exceeds 2.0, the pore volume of the porous particles hardly increases. On the other hand, when the molar ratio is less than 0.05, the pore volume becomes small. When preparing hollow particles, the molar ratio of MOx / SiO ₂ is preferably in the range of 0.25 to 2.0.

Second step: Removal of inorganic compound other than silica from porous particles In the second step, inorganic compounds other than silica (elements other than silicon and oxygen) are obtained from the porous particle precursor obtained in the first step. At least a portion is selectively removed. As a specific removal method, the inorganic compound in the porous particle precursor is dissolved and removed using a mineral acid or an organic acid, or is contacted with a cation exchange resin for ion exchange removal.

  The porous particle precursor obtained in the first step is a particle having a network structure in which silicon and an inorganic compound constituent element are bonded via oxygen. By removing the inorganic compound (elements other than silicon and oxygen) from the porous particle precursor in this way, porous particles having a larger porosity and a larger pore volume can be obtained. Further, if the amount of removing the inorganic oxide (elements other than silicon and oxygen) from the porous particle precursor is increased, the hollow particles can be prepared.

  In addition, prior to removing inorganic compounds other than silica from the porous particle precursor, a silicic acid solution obtained by removing the alkali metal salt of silica from the porous particle precursor dispersion obtained in the first step. Alternatively, it is preferable to form a silica protective film by adding a hydrolyzable organosilicon compound. The thickness of the silica protective film may be 0.5 to 15 nm. Even if the silica protective film is formed, the protective film in this step is porous and thin, so that it is possible to remove inorganic compounds other than silica described above from the porous particle precursor.

  By forming such a silica protective film, inorganic compounds other than silica described above can be removed from the porous particle precursor while maintaining the particle shape. Moreover, when forming the silica coating layer described later, the pores of the porous particles are not blocked by the coating layer, and therefore, the silica coating layer described later is formed without reducing the pore volume. I can do it. Note that when the amount of the inorganic compound to be removed is small, it is not always necessary to form a protective film because the particles are not broken.

  When preparing hollow particles, it is desirable to form this silica protective film. When preparing the hollow particles, the inorganic compound is removed to obtain a hollow particle precursor comprising a silica protective film, a solvent in the silica protective film, and an undissolved porous solid, and the hollow particles When a coating layer to be described later is formed on the precursor, the formed coating layer becomes a particle wall to form hollow particles.

The amount of the silica source added for forming the silica protective film is preferably small as long as the particle shape can be maintained. If the amount of the silica source is too large, the silica protective film becomes too thick, and it may be difficult to remove inorganic compounds other than silica from the porous particle precursor. The hydrolyzable organic silicon compound used for the silica protective film formed of the general formula _{R n Si (OR ') 4} -n [R, R': an alkyl group, an aryl group, a vinyl group, such as acrylic group An alkoxysilane represented by a hydrocarbon group, n = 0, 1, 2, or 3] can be used. In particular, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane are preferably used.

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

  In the case where the dispersion medium of the porous particle precursor is water alone or the ratio of water to the organic solvent is high, it is possible to form a silica protective film using a silicic acid solution. When a silicic acid solution is used, a predetermined amount of the silicic acid solution is added to the dispersion, and at the same time an alkali is added to deposit the silicic acid solution on the surface of the porous particles. In addition, you may produce a silica protective film using a silicic acid liquid and the said alkoxysilane together.

Third step: Formation of silica coating layer In the third step, a hydrolyzable organosilicon compound or silicic acid solution is added to the porous particle dispersion prepared in the second step (in the case of hollow particles, a hollow particle precursor dispersion). Is added to coat the surface of the particles with a polymer such as a hydrolyzable organosilicon compound or a silicic acid solution to form a silica coating layer.

The hydrolyzable organic silicon compound used for the silica coating layer formed, the above-mentioned such general formula _{R n Si (OR ') 4} -n [R, R': an alkyl group, an aryl group, a vinyl group, An alkoxysilane represented by a hydrocarbon group such as an acryl group, n = 0, 1, 2, or 3] can be used. In particular, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane are preferably used.

  As an addition method, a solution obtained by adding a small amount of alkali or acid as a catalyst to a mixed solution of these alkoxysilanes, pure water, and alcohol is used as a dispersion of the porous particles (in the case of hollow particles, hollow particle precursor). In addition, the silicic acid polymer produced by hydrolyzing alkoxysilane is deposited on the surface of the porous particles (in the case of hollow particles, hollow particle precursors). At this time, alkoxysilane, alcohol, and catalyst may be simultaneously added to the dispersion. As the alkali catalyst, ammonia, an alkali metal hydroxide, or an amine can be used. As the acid catalyst, various inorganic acids and organic acids can be used.

  When the dispersion medium of the porous particles (cavity particle precursor in the case of hollow particles) is water alone or a mixed solvent with an organic solvent and the mixed solvent has a high ratio of water to the organic solvent, a silicate solution You may form a coating layer using. The silicic acid solution is an aqueous solution of a low silicic acid polymer obtained by dealkalizing an aqueous solution of an alkali metal silicate such as water glass by ion exchange treatment.

  The silicic acid solution is added to the dispersion of porous particles (in the case of hollow particles, hollow particle precursors), and at the same time, alkali is added to make the low-silicic acid polymer into porous particles (in the case of hollow particles, hollow particle precursors). ) Deposit on the surface. A silicic acid solution may be used in combination with the alkoxysilane for forming a coating layer. The addition amount of the organosilicon compound or silicic acid solution used for forming the coating layer only needs to be sufficient to cover the surface of the colloidal particles, and the finally obtained silica coating layer has a thickness of 1 to 20 nm. In such an amount, it is added in a dispersion of porous particles (in the case of hollow particles, hollow particle precursor) in a dispersion. When the silica protective film is formed, the organosilicon compound or the silicate solution is added in such an amount that the total thickness of the silica protective film and the silica coating layer is in the range of 1 to 20 nm.

  Next, the dispersion liquid of the particles on which the coating layer is formed is heat-treated. By the heat treatment, in the case of porous particles, the silica coating layer covering the surface of the porous particles is densified, and a dispersion of composite particles in which the porous particles are coated with the silica coating layer is obtained. In the case of the hollow particle precursor, the formed coating layer is densified to form hollow particle walls, and a dispersion of hollow particles having cavities filled with a solvent, gas, or porous solid content is obtained.

  The heat treatment temperature at this time is not particularly limited as long as it can close the fine pores of the silica coating layer, and is preferably in the range of 80 to 300 ° C. When the heat treatment temperature is less than 80 ° C., the fine pores of the silica coating layer may not be completely closed and densified, and the treatment time may take a long time. Further, when the heat treatment temperature exceeds 300 ° C. for a long time, fine particles may be formed, and the effect of low refractive index may not be obtained.

  The refractive index of the inorganic fine particles thus obtained is as low as less than 1.44. Such inorganic fine particles are presumed to have a low refractive index because the porosity inside the porous particles is maintained or the inside is hollow.

In the low refractive index layer used in the present invention, in addition to the silica fine particles, a silicon dioxide polymer is an essential component. The silicon dioxide polymer is a hydrolyzate of an alkoxysilicon compound (hereinafter also referred to as alkoxysilane) and subsequent condensation. It preferably contains a condensate formed by the reaction. In particular, it is preferable to contain a SiO ₂ sol prepared by adjusting an alkoxysilicon compound represented by the following general formula (1) and / or (2) or a hydrolyzate thereof.

General formula (1) R1-Si (OR2) ₃
General formula (2) Si (OR2) ₄
(In the formula, R1 represents a methyl group, an ethyl group, a vinyl group, or an organic group containing an acryloyl group, a methacryloyl group, an amino group or an epoxy group, and R2 represents a methyl group or an ethyl group)
Hydrolysis of the alkoxysilicon compound is performed by dissolving the alkoxysilicon compound in a suitable solvent. Examples of the solvent to be used include ketones such as methyl ethyl ketone, alcohols such as methanol, ethanol and isopropyl alcohol butanol, esters such as ethyl acetate, and mixtures thereof.

  A slightly larger amount of water than the amount required for hydrolysis is added to a solution obtained by dissolving the alkoxysilicon compound in a solvent, and the temperature is 15 to 35 ° C., preferably 20 to 30 ° C. for 1 to 48 hours, preferably 3 Stir for ~ 36 hours.

  In the hydrolysis, a catalyst is preferably used. As such a catalyst, an acid such as hydrochloric acid, nitric acid, sulfuric acid or acetic acid is preferably used. These acids are used in an aqueous solution of about 0.001N to 20.0N, preferably about 0.005 to 5.0N. The water in the catalyst aqueous solution can be water for hydrolysis.

  The alkoxy silicon compound is hydrolyzed for a predetermined time, the prepared alkoxy silicon hydrolyzed solution is diluted with a solvent, and other necessary additives are mixed to prepare a coating solution for a low refractive index layer. The low refractive index layer can be formed on the base material by applying and drying on a base material such as a film.

  In the present invention, the alkoxysilicon compound used for the preparation of the low refractive index layer coating solution is preferably represented by the following general formula (3).

General formula (3) R4-nSi (OR ') n
In the general formula, R ′ represents an alkyl group, R represents a hydrogen atom or a monovalent substituent, and n represents 3 or 4.

  Examples of the alkyl group represented by R ′ include groups such as a methyl group, an ethyl group, a propyl group, and a butyl group, which may have a substituent, and the substituent exhibits properties as an alkoxysilane. If it is, there is no restriction | limiting in particular, For example, although you may substitute by halogen atoms, such as a fluorine, an alkoxy group, etc., More preferably, it is an unsubstituted alkyl group, and especially a methyl group and an ethyl group are preferable.

  The monovalent substituent represented by R is not particularly limited, and examples thereof include an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aromatic heterocyclic group, and a silyl group. Of these, an alkyl group, a cycloalkyl group, and an alkenyl group are preferable. These may be further substituted. Examples of the substituent for R include a halogen atom such as a fluorine atom and a chlorine atom, an amino group, an epoxy group, a mercapto group, a hydroxyl group, and an acetoxy group.

Specific preferred examples of the alkoxysilane represented by the general formula include tetramethoxysilane, tetraethoxysilane (TEOS), tetra n-propoxy silane, tetraisopropoxy silane, tetra n-butoxy silane, tetra t- Butoxysilane, tetrakis (methoxyethoxy) silane, tetrakis (methoxypropoxy) silane,
Further, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-butyltrimethoxysilane, i-butyltrimethoxysilane, n-hexyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3 -Mercaptopropyltrimethoxysilane, acetoxytriethoxysilane, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) trimethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, (3, 3, - trifluoropropyl) trimethoxysilane, pentafluorophenyl phenylpropyl trimethoxysilane, further, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane and the like.

  Alternatively, quantified silicon compounds such as silicate 40, silicate 45, silicate 48, and M silicate 51 manufactured by Tama Chemical, in which these compounds are partially condensed may be used.

  Since the alkoxysilane has a silicon alkoxide group that can be hydrolyzed and polycondensed, these alkoxysilanes are crosslinked by hydrolysis and condensation to form a network structure of the polymer compound. A layer containing uniform silicon oxide is formed on the base material by applying it on the base material and drying it as a refractive index layer coating solution.

  The hydrolysis reaction can be carried out by a known method and dissolved in the presence of a predetermined amount of water and a hydrophilic organic solvent such as methanol, ethanol or acetonitrile so that the hydrophobic alkoxysilane and water can be easily mixed. -After mixing, a hydrolysis catalyst is added to hydrolyze and condense the alkoxysilane. Usually, by carrying out hydrolysis and condensation reaction at 10 ° C. to 100 ° C., a liquid silicate oligomer having two or more hydroxyl groups is generated, and a hydrolyzed solution is formed. The degree of hydrolysis can be appropriately adjusted depending on the amount of water used.

  In the present invention, as a solvent to be added to alkoxysilane together with water, methanol and ethanol are preferable because they are inexpensive and the properties of the resulting film are excellent and the hardness is good. Although isopropanol, n-butanol, isobutanol, octanol, and the like can be used, the hardness of the obtained film tends to be low. The amount of the solvent is 50 to 400 parts by mass, preferably 100 to 250 parts by mass with respect to 100 parts by mass of the tetraalkoxysilane before hydrolysis.

  In this way, a hydrolyzed solution is prepared, diluted with a solvent, and if necessary, an additive is added and mixed with components necessary to form a low refractive index layer coating solution. A coating solution is used.

<Hydrolysis catalyst>
Examples of the hydrolysis catalyst include acids, alkalis, organic metals, metal alkoxides, etc. In the present invention, inorganic acids or organic acids such as sulfuric acid, hydrochloric acid, nitric acid, hypochlorous acid, and boric acid are preferable. In particular, carboxylic acids such as nitric acid and acetic acid, polyacrylic acid, benzenesulfonic acid, paratoluenesulfonic acid, methylsulfonic acid and the like are preferable, and among these, nitric acid, acetic acid, citric acid, tartaric acid and the like are preferably used. In addition to the citric acid and tartaric acid, levulinic acid, formic acid, propionic acid, malic acid, succinic acid, methyl succinic acid, fumaric acid, oxaloacetic acid, pyruvic acid, 2-oxoglutaric acid, glycolic acid, D-glyceric acid, D- Gluconic acid, malonic acid, maleic acid, oxalic acid, isocitric acid, lactic acid and the like are also preferably used.

  Of these, those which volatilize the acid during drying and do not remain in the film are preferred, and those having a low boiling point are preferred. Therefore, acetic acid and nitric acid are particularly preferable.

  The added amount is 0.001 to 10 parts by mass, preferably 0.005 to 5 parts by mass with respect to 100 parts by mass of the alkoxysilicon compound (for example, tetraalkoxysilane) to be used. In addition, the amount of water added may be equal to or greater than the amount that the partial hydrolyzate can theoretically hydrolyze to 100%, and an amount equivalent to 100 to 300%, preferably an amount equivalent to 100 to 200% is added.

  The hydrolysis solution is allowed to stand for a predetermined time after the start of hydrolysis, and used after the progress of hydrolysis reaches a predetermined level. The standing time is a time during which the above-described crosslinking by hydrolysis and condensation proceeds sufficiently to obtain desired film characteristics. Specifically, depending on the type of acid catalyst used, for example, acetic acid is preferably 15 hours or more at room temperature, and nitric acid is preferably 2 hours or more. The aging temperature affects the aging time. Generally, the aging proceeds quickly at high temperatures, but when heated to 100 ° C. or higher, gelation occurs, so heating at 20 to 60 ° C. and keeping the temperature are appropriate.

  The above-mentioned hollow fine particles and additives are added to the silicate oligomer solution thus formed by hydrolysis and condensation, and necessary dilution is performed to prepare a low refractive index layer coating solution, which is applied to the above-mentioned transparent support. By applying and drying, a layer containing an excellent silicon oxide film as a low refractive index layer can be formed.

  In the present invention, in addition to the above alkoxysilane, for example, a modified product modified with a silane compound (monomer, oligomer, polymer) having a functional group such as an epoxy group, an amino group, an isocyanate group, or a carboxyl group. It may be used alone or in combination.

<Additive>
If necessary, the low refractive index layer coating solution may further contain additives such as a silane coupling agent and a curing agent. The silane coupling agent is a compound represented by the general formula (2).

  Specific examples include vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and 3- (2-aminoethylaminopropyl) trimethoxysilane.

  Examples of the curing agent include organic acid metal salts such as sodium acetate and lithium acetate, and sodium acetate is particularly preferable. The amount of addition to the silicon alkoxysilane hydrolysis solution is preferably in the range of about 0.1 to 1 part by mass with respect to 100 parts by mass of the solid content present in the hydrolysis solution.

  The coating solution for the low refractive index layer used in the present invention includes various leveling agents, surfactants, in addition to the silicone-based nonionic surfactant having a viscosity of 1 to 500 CS at 25 ° C., which is preferable in the present invention. It is preferable to add a low surface tension substance such as silicone oil.

  Specific examples of the silicone oil include L-45, L-9300, FZ-3704, FZ-3703, FZ-3720, FZ-3786, FZ-3501, and FZ-3504 of Nippon Unicar Co., Ltd. , FZ-3508, FZ-3705, FZ-3707, FZ-3710, FZ-3750, FZ-3760, FZ-3785, FZ-3785, Y-7499, Shin-Etsu Chemical KF96L, KF96, KF96H, KF99, KF54 , KF965, KF968, KF56, KF995, KF351, KF352, KF353, KF354, KF355, KF615, KF618, KF945, KF6004, FL100 and the like.

  When these components are added in an excessive amount, they cause repelling during coating. Therefore, it is preferable to add them in a range of 0.01 to 3% by mass with respect to the solid component in the coating solution.

<solvent>
Solvents used in the coating solution for coating the low refractive index layer are alcohols such as methanol, ethanol, 1-propanol, 2-propanol and butanol; ketones such as acetone, methyl ethyl ketone and cyclohexanone; benzene, toluene, Aromatic hydrocarbons such as xylene; glycols such as ethylene glycol, propylene glycol, hexylene glycol; ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, diethyl cellosolve, diethyl carbitol, propylene glycol monomethyl Examples include glycol ethers such as ether; N-methylpyrrolidone, dimethylformamide, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, water, etc., and these may be used alone or in combination of two or more. That.

<Application method>
As a method of applying the low refractive index layer, known methods such as dipping, spin coating, knife coating, bar coating, air doctor coating, blade coating, squeeze coating, reverse roll coating, gravure roll coating, curtain coating, spray coating, die coating, etc. A coating method or a known inkjet method can be used, and a coating method capable of continuous coating or thin film coating is preferably used. The coating amount is suitably 0.1 to 30 μm, preferably 0.5 to 15 μm in terms of wet film thickness. The coating speed is preferably 10 to 80 m / min.

  In the present invention, it is also preferable to further provide the following high refractive index layer to form an antireflection layer having a plurality of layers.

(High refractive index layer)
The high refractive index layer is not particularly limited as long as a predetermined refractive index layer is obtained, but is preferably composed of metal oxide fine particles having a high refractive index, a binder, and the like. In addition, you may contain an additive.

  In addition, the high refractive index layer may be called a medium refractive index layer in the case of a refractive index of 1.55 to 1.75, and a high refractive index layer in the case of a refractive index of 1.75 to 2.20. The thickness of the high refractive index layer and the medium refractive index layer is preferably 5 nm to 1 μm, more preferably 10 nm to 0.2 μm, and most preferably 30 nm to 0.1 μm. The coating can be performed in the same manner as the coating method for the low refractive index layer.

<Metal oxide fine particles>
Although metal oxide fine particles are not particularly limited, for example, titanium dioxide, aluminum oxide (alumina), zirconium oxide (zirconia), zinc oxide, antimony-doped tin oxide (ATO), antimony pentoxide, indium-tin oxide (ITO), Iron oxide or the like can be used as a main component. A mixture of these may also be used. When titanium dioxide is used, photocatalytic activity can be achieved by using metal oxide particles having a core / shell structure in which titanium dioxide is the core and the shell is coated with alumina, silica, zirconia, ATO, ITO, antimony pentoxide, or the like. It is preferable in terms of suppression.

When ATO or ITO is used, the effect as an antistatic layer can be exhibited, and the surface specific resistance is preferably adjusted in the range of 1.0 × 10 ⁶ Ω / □ to 1.0 × 10 ¹⁰ Ω / □. The surface specific resistance is measured using a terraohm meter model VE-30 manufactured by Kawaguchi Electric Co., Ltd. for 24 hours under conditions of 25 ° C. and 55% RH.

  The refractive index of the metal oxide fine particles is preferably 1.80 to 2.60, more preferably 1.90 to 2.50. The average particle diameter of the primary particles of the metal oxide fine particles is 5 nm to 200 nm, more preferably 10 to 150 nm. If the particle size is too small, the metal oxide fine particles tend to aggregate and the dispersibility deteriorates. If the particle size is too large, the haze increases, which is not preferable. The shape of the inorganic fine particles is preferably a rice grain shape, a needle shape, a spherical shape, a cubic shape, a spindle shape or an indefinite shape.

  The metal oxide fine particles may be surface-treated with an organic compound. Examples of the organic compound used for the surface treatment include polyols, alkanolamines, stearic acid, silane coupling agents, and titanate coupling agents. Among these, the above-mentioned silane coupling agent is most preferable. Two or more kinds of surface treatments may be combined.

  By appropriately selecting the kind and addition ratio of the metal oxide, a high refractive index layer and a medium refractive index layer having a desired refractive index can be obtained.

<binder>
The binder is added to improve the film formability and physical properties of the coating film. As the binder, for example, actinic radiation curable resin, acrylamide derivative, polyfunctional acrylate, acrylic resin or methacrylic resin that can be used in the hard coat layer can be used.

(Metal compounds, silane coupling agents)
As other additives, a metal compound, a silane coupling agent, or the like may be added. Metal compounds and silane coupling agents can also be used as binders.

  As the metal compound, a compound represented by the following general formula (4) or a chelate compound thereof can be used.

General formula (4): AnMBx-n
In the formula, M represents a metal atom, A represents a hydrolyzable functional group or a hydrocarbon group having a hydrolyzable functional group, and B represents an atomic group covalently or ionically bonded to the metal atom M. x represents the valence of the metal atom M, and n represents an integer of 2 or more and x or less.

  Examples of the hydrolyzable functional group A include halogens such as alkoxyl groups and chloro atoms, ester groups and amide groups. The metal compound belonging to the above formula (4) includes an alkoxide having two or more alkoxyl groups bonded directly to a metal atom, or a chelate compound thereof. Preferable metal compounds include titanium alkoxides, zirconium alkoxides, silicon alkoxides, and chelate compounds thereof from the viewpoints of the effect of reinforcing the refractive index and coating film strength, ease of handling, material cost, and the like. Titanium alkoxide has a high reaction rate and a high refractive index and is easy to handle. However, since it has a photocatalytic action, its light resistance deteriorates when added in a large amount. Zirconium alkoxide has a high refractive index but tends to become cloudy, so care must be taken in dew point management during coating. Silicon alkoxide has a slow reaction rate and a low refractive index, but is easy to handle and has excellent light resistance. Since the silane coupling agent can react with both the inorganic fine particles and the organic polymer, a tough coating film can be formed. Moreover, since titanium alkoxide has the effect of accelerating the reaction of the ultraviolet curable resin and metal alkoxide, the physical properties of the coating film can be improved by adding a small amount.

  Examples of the titanium alkoxide include tetramethoxy titanium, tetraethoxy titanium, tetra-iso-propoxy titanium, tetra-n-propoxy titanium, tetra-n-butoxy titanium, tetra-sec-butoxy titanium, tetra-tert-butoxy titanium, and the like. Is mentioned.

  Examples of the zirconium alkoxide include tetramethoxy zirconium, tetraethoxy zirconium, tetra-iso-propoxy zirconium, tetra-n-propoxy zirconium, tetra-n-butoxy zirconium, tetra-sec-butoxy zirconium, tetra-tert-butoxy zirconium and the like. Is mentioned.

  The silicon alkoxide and the silane coupling agent are compounds represented by the following general formula (5).

Formula (5): RmSi (OR ′) n
In the formula, R is an alkyl group (preferably an alkyl group having 1 to 10 carbon atoms), or a reaction such as a vinyl group, a (meth) acryloyl group, an epoxy group, an amide group, a sulfonyl group, a hydroxyl group, a carboxyl group, or an alkoxyl group. R ′ represents an alkyl group (preferably an alkyl group having 1 to 10 carbon atoms), and m + n is 4.

  Specifically, tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, tetrapenta Ethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, hexyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane , Γ-glycidoxypropyltrimethoxysilane, 3- (2-aminoethylaminopropyl) trimethoxysilane and the like.

  Preferred chelating agents for forming a chelate compound by coordination with a free metal compound include alkanolamines such as diethanolamine and triethanolamine, glycols such as ethylene glycol, diethylene glycol and propylene glycol, acetylacetone and acetoacetic acid. Examples thereof include ethyl and the like having a molecular weight of 10,000 or less. By using these chelating agents, it is possible to form a chelate compound that is stable against moisture mixing and is excellent in the effect of reinforcing the coating film.

  The addition amount of the metal compound is preferably less than 5% by mass in terms of metal oxide in the medium refractive index composition, and less than 20% by mass in terms of metal oxide in the high refractive index composition. Is preferred.

(Transparent support)
Next, a transparent support (hereinafter also referred to as a transparent film) that can be used in the present invention will be described.

  As the transparent film used in the present invention, it is preferable that it is easy to manufacture, has good adhesion with the hard coat layer, is optically isotropic, and is optically transparent. Can be mentioned.

  The term “transparent” as used in the present invention means that the visible light transmittance is 60% or more, preferably 80% or more, and particularly preferably 90% or more.

  Although it will not specifically limit if it has said property, For example, a cellulose-ester type film, a polyester-type film, a polycarbonate-type film, a polyarylate-type film, a polysulfone (a polyether sulfone is also included) film, a polyethylene terephthalate, polyethylene Polyester film such as naphthalate, polyethylene film, polypropylene film, cellophane, cellulose diacetate film, cellulose triacetate, cellulose acetate butyrate film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene film, Polycarbonate film, cycloolefin polymer film (Arton (manufactured by JSR), Onex, ZEONOR (manufactured by Nippon Zeon Co., Ltd.), polymethylpentene film, polyetherketone film, polyetherketoneimide film, polyamide film, fluororesin film, nylon film, polymethylmethacrylate film, acrylic film, glass plate, etc. Can be mentioned. Among them, cellulose triacetate film, polycarbonate film, and polysulfone (including polyethersulfone) are preferable, and in the present invention, cellulose ester film (for example, Konica Minoltack, product names KC8UX2MW, KC4UX2MW, KC8UY, KC4UNY, KC5UN, KC12UR ( Konica Minolta Opto Co., Ltd.)) is preferably used from the viewpoints of production, cost, transparency, isotropy, adhesion and the like. These films may be films produced by melt casting film formation or films produced by solution casting film formation.

The optical properties of the transparent film thickness direction retardation R _t is from 0 to 300 nm, retardation R ₀ in the plane direction those 0~1000nm is preferably used.

  In the present invention, it is preferable to use a cellulose ester film as the transparent film. As the cellulose ester, cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate are preferable. Among them, cellulose acetate butyrate, cellulose acetate phthalate, and cellulose acetate propionate are preferably used.

  In particular, when the substitution degree of the acetyl group is X and the substitution degree of the propionyl group or butyryl group is Y, the hard coat layer and the antireflection layer are formed on the transparent film having a mixed fatty acid ester of cellulose in which X and Y are in the following ranges. An antireflection film provided with is preferably formed.

2.3 ≦ X + Y ≦ 3.0
0.1 ≦ Y ≦ 1.2
In particular, 2.5 ≦ X + Y ≦ 2.85
It is preferable that 0.3 ≦ Y ≦ 1.2.

  When cellulose ester is used as the transparent film used in the present invention, the cellulose used as a raw material for the cellulose ester is not particularly limited, and examples thereof include cotton linters, wood pulp (derived from coniferous trees and hardwoods), kenaf and the like. . Moreover, the cellulose ester obtained from them can be mixed and used in arbitrary ratios, respectively. When the acylating agent is an acid anhydride (acetic anhydride, propionic anhydride, butyric anhydride), these cellulose esters use an organic solvent such as acetic acid or an organic solvent such as methylene chloride, and It can be obtained by reacting with a cellulose raw material using a protic catalyst.

When the acylating agent is acid chloride (CH ₃ COCl, C ₂ H ₅ COCl, C ₃ H ₇ COCl), the reaction is carried out using a basic compound such as an amine as a catalyst. Specifically, it can be synthesized with reference to the method described in JP-A-10-45804. In addition, the cellulose ester used in the present invention is obtained by mixing and reacting the amount of the acylating agent in accordance with the degree of substitution. In the cellulose ester, these acylating agents react with hydroxyl groups of cellulose molecules. Cellulose molecules are composed of many glucose units linked together, and the glucose unit has three hydroxyl groups. The number of acyl groups derived from these three hydroxyl groups is called the degree of substitution (mol%). For example, cellulose triacetate has acetyl groups bonded to all three hydroxyl groups of the glucose unit (actually 2.6 to 3.0).

  The cellulose ester used in the present invention is a mixed fatty acid ester of cellulose in which a propionate group or a butyrate group is bonded in addition to an acetyl group such as cellulose acetate propionate, cellulose acetate butyrate, or cellulose acetate propionate butyrate. Is particularly preferably used. The butyryl group forming butyrate may be linear or branched.

  Cellulose acetate propionate containing a propionate group as a substituent has excellent water resistance and is useful as a film for liquid crystal image display devices.

  The measuring method of the substitution degree of an acyl group can be measured according to the provisions of ASTM-D817-96.

  The number average molecular weight of the cellulose ester is preferably 70000 to 250,000, since it has high mechanical strength when molded and an appropriate dope viscosity, and more preferably 80000 to 150,000.

  These cellulose esters are pressurized by applying a cellulose ester solution (dope) generally called a solution casting film forming method onto, for example, an endless metal belt for infinite transport or a support for casting of a rotating metal drum. It is preferable to manufacture the dope from a die by casting (casting).

  The organic solvent used for the preparation of these dopes is preferably capable of dissolving the cellulose ester and having an appropriate boiling point, for example, methylene chloride, methyl acetate, ethyl acetate, amyl acetate, methyl acetoacetate, acetone, tetrahydrofuran 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol, 1,3-difluoro-2 -Propanol, 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3 , 3,3-pentafluoro-1-propanol, nitroethane, 1,3-dimethyl-2-imidazolidinone, etc. It is possible, organic halogen compounds such as methylene chloride, dioxolane derivatives, methyl acetate, ethyl acetate, acetone, methyl acetoacetate, and the like are preferable organic solvents (i.e., good solvent), and as.

  Moreover, as shown in the following film forming process, it is used from the viewpoint of preventing foaming in the web when the solvent is dried from the web (dope film) formed on the casting support in the solvent evaporation process. The boiling point of the organic solvent is preferably 30 to 80 ° C. For example, the good solvent described above has a boiling point of methylene chloride (boiling point 40.4 ° C), methyl acetate (boiling point 56.32 ° C), acetone (boiling point 56.56 ° C). 3 ° C.), ethyl acetate (boiling point 76.82 ° C.) and the like.

  Among the good solvents described above, methylene chloride or methyl acetate, which is excellent in solubility, is preferably used.

  In addition to the organic solvent, it is preferable to contain 0.1 to 40% by mass of an alcohol having 1 to 4 carbon atoms. It is particularly preferable that the alcohol is contained at 5 to 30% by mass. After casting the dope described above onto a casting support, the solvent starts to evaporate and the alcohol ratio increases and the web (dope film) gels, making the web strong and peeling from the casting support. It is also used as a gelling solvent for facilitating the dissolution, and when these ratios are small, it also has a role of promoting dissolution of the cellulose ester of the non-chlorine organic solvent.

  Examples of the alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol and the like.

  Of these solvents, ethanol is preferred because it has good dope stability, relatively low boiling point, good drying properties, and no toxicity. It is preferable to use a solvent containing 5 to 30% by mass of ethanol with respect to 70 to 95% by mass of methylene chloride. Methyl acetate can be used in place of methylene chloride. At this time, the dope may be prepared by a cooling dissolution method.

  When a cellulose ester film is used for the antireflection film of the present invention, it is preferable to contain the following plasticizer. Examples of plasticizers include phosphate ester plasticizers, phthalate ester plasticizers, trimellitic acid ester plasticizers, pyromellitic acid plasticizers, glycolate plasticizers, citrate ester plasticizers, and polyesters. A plasticizer or the like can be preferably used.

  For phosphate plasticizers, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenylbiphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc. For phthalate ester plasticizers, diethyl phthalate, dimethoxy Ethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, diphenyl phthalate, dicyclohexyl phthalate, and other trimellitic acid plasticizers include tributyl trimellitate, triphenyl trimellitate, triethyl For pyromellitic acid ester plasticizers such as trimellitate, tetrabutylpyromellitate, In the case of glycolate plasticizers such as lupyromelitate and tetraethylpyromellitate, triacetin, tributyrin, ethylphthalylethyl glycolate, methylphthalylethylglycolate, butylphthalylbutylglycolate, etc. Citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tri-n-butyl citrate, acetyl tri-n- (2-ethylhexyl) citrate and the like can be preferably used. Examples of other carboxylic acid esters include trimethylolpropane tribenzoate, butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters.

  As the polyester plasticizer, a copolymer of a dibasic acid such as an aliphatic dibasic acid, an alicyclic dibasic acid, or an aromatic dibasic acid and a glycol can be used. The aliphatic dibasic acid is not particularly limited, and adipic acid, sebacic acid, phthalic acid, terephthalic acid, 1,4-cyclohexyl dicarboxylic acid and the like can be used. As the glycol, ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol and the like can be used. These dibasic acids and glycols may be used alone or in combination of two or more.

  The amount of these plasticizers used is preferably from 1 to 20% by weight, particularly preferably from 3 to 13% by weight, based on the cellulose ester, in terms of film performance, processability and the like.

  For the long film for the antireflection film of the present invention, an ultraviolet absorber is preferably used.

  As the ultraviolet absorber, those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties.

  Specific examples of the ultraviolet absorber preferably used in the present invention include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. However, it is not limited to these.

  Specific examples of the benzotriazole-based ultraviolet absorbers include the following ultraviolet absorbers, but the present invention is not limited thereto.

UV-1: 2- (2'-hydroxy-5'-methylphenyl) benzotriazole UV-2: 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole UV-3 : 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole UV-4: 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl)- 5-Chlorobenzotriazole UV-5: 2- (2'-hydroxy-3 '-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl) benzotriazole UV-6: 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol)
UV-7: 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole UV-8: 2- (2H-benzotriazol-2-yl) -6 (Linear and side chain dodecyl) -4-methylphenol (TINUVIN171, manufactured by Ciba)
UV-9: Octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H-benzotriazol-2-yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl- 4-Hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate (TINUVIN109, manufactured by Ciba)
Moreover, although the following specific example is shown as a benzophenone series ultraviolet absorber, this invention is not limited to these.

UV-10: 2,4-dihydroxybenzophenone UV-11: 2,2'-dihydroxy-4-methoxybenzophenone UV-12: 2-hydroxy-4-methoxy-5-sulfobenzophenone UV-13: Bis (2-methoxy -4-hydroxy-5-benzoylphenylmethane)
As the ultraviolet absorber preferably used in the present invention, a benzotriazole-based ultraviolet absorber and a benzophenone-based ultraviolet absorber that are highly transparent and excellent in preventing the deterioration of the polarizing plate and the liquid crystal are preferable, and unnecessary coloring is less. A benzotriazole-based ultraviolet absorber is particularly preferably used.

  Moreover, the ultraviolet absorber whose distribution coefficient described in Unexamined-Japanese-Patent No. 2001-187825 is 9.2 or more improves the surface quality of a long film, and is excellent also in applicability | paintability. In particular, it is preferable to use an ultraviolet absorber having a distribution coefficient of 10.1 or more.

  Further, the polymer ultraviolet absorbers described in the general formula (1) or general formula (2) described in JP-A-6-148430 and the general formulas (3), (6), and (7) of Japanese Patent Application No. 2000-156039 ( Alternatively, an ultraviolet absorbing polymer) is also preferably used. As a polymer ultraviolet absorber, PUVA-30M (manufactured by Otsuka Chemical Co., Ltd.) and the like are commercially available.

  Moreover, in order to provide slipperiness to the cellulose-ester film used for this invention, the microparticles | fine-particles similar to what is described with the coating layer containing the below-mentioned actinic radiation curable resin can be used.

<Fine particles>
The cellulose ester film that can be used in the present invention preferably contains fine particles.

  As fine particles, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, Mention may be made of magnesium silicate and calcium phosphate. Fine particles containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable.

  The average primary particle size of the fine particles is preferably 5 to 50 nm, and more preferably 7 to 20 nm. These are preferably contained mainly as secondary aggregates having a particle size of 0.05 to 0.3 μm. The content of these fine particles in the cellulose ester film is preferably 0.05 to 1% by mass, particularly preferably 0.1 to 0.5% by mass. In the case of a cellulose ester film having a multilayer structure by the co-casting method, it is preferable to contain fine particles of this addition amount on the surface.

  Silicon dioxide fine particles are commercially available, for example, under the trade names Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.). I can do it.

  Zirconium oxide fine particles are commercially available under the trade names of Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used.

  Examples of the polymer include silicone resin, fluorine resin, and acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.) It is marketed by name and can be used.

  Among these, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large effect of reducing the friction coefficient while keeping the turbidity of the cellulose ester film low. In the cellulose ester film used in the present invention, the dynamic friction coefficient on the back side of the hard coat layer is preferably 1.0 or less.

<Method for producing cellulose ester film>
Next, the manufacturing method of the cellulose-ester film which can be used for this invention is demonstrated.

  The cellulose ester film that can be used in the present invention is prepared by dissolving a cellulose ester and an additive in a solvent to prepare a dope, casting a dope on a belt-shaped or drum-shaped metal support, It is performed by a step of drying the stretched dope as a web, a step of peeling from the metal support, a step of stretching or maintaining the width, a step of further drying, and a step of winding the finished film.

  The process for preparing the dope will be described. The concentration of cellulose ester in the dope is preferably higher because the drying load after casting on the metal support can be reduced. However, if the concentration of cellulose ester is too high, the load during filtration increases and the filtration accuracy increases. Becomes worse. The concentration for achieving both of these is preferably 10 to 35% by mass, and more preferably 15 to 25% by mass.

  The solvent used in the dope of the present invention may be used alone or in combination of two or more. However, it is preferable from the viewpoint of production efficiency that a good solvent and a poor solvent of cellulose ester are mixed and used. The more solvent is preferable from the viewpoint of solubility of the cellulose ester. The preferable range of the mixing ratio of the good solvent and the poor solvent is 70 to 98% by mass for the good solvent and 2 to 30% by mass for the poor solvent. With a good solvent and a poor solvent, what dissolve | melts the cellulose ester to be used independently is defined as a good solvent, and what poorly swells or does not melt | dissolve is defined as a poor solvent. Therefore, depending on the acyl group substitution degree of the cellulose ester, the good solvent and the poor solvent change. For example, when acetone is used as the solvent, the cellulose ester acetate ester (acetyl group substitution degree 2.4) and cellulose acetate propionate are good. As a solvent, cellulose acetate (acetyl group substitution degree 2.8) is a poor solvent.

  Although the good solvent used for this invention is not specifically limited, Organic halogen compounds, such as a methylene chloride, dioxolanes, acetone, methyl acetate, methyl acetoacetate, etc. are mentioned. Particularly preferred is methylene chloride or methyl acetate.

  Moreover, although the poor solvent used for this invention is not specifically limited, For example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone, etc. are used preferably. Moreover, it is preferable that 0.01-2 mass% of water contains in dope.

  A general method can be used as a method of dissolving the cellulose ester when preparing the dope described above. When heating and pressurization are combined, it is possible to heat above the boiling point at normal pressure. It is preferable to stir and dissolve while heating at a temperature that is equal to or higher than the boiling point of the solvent at normal pressure and that the solvent does not boil under pressure, in order to prevent the generation of massive undissolved materials called gels and mamacos. Moreover, after mixing a cellulose ester with a poor solvent and making it wet or swell, the method of adding a good solvent and melt | dissolving is also used preferably.

  The pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or a method of increasing the vapor pressure of the solvent by heating. Heating is preferably performed from the outside. For example, a jacket type is preferable because temperature control is easy.

  The heating temperature with the addition of the solvent is preferably higher from the viewpoint of the solubility of the cellulose ester, but if the heating temperature is too high, the required pressure increases and the productivity deteriorates. A preferable heating temperature is 45 to 120 ° C, more preferably 60 to 110 ° C, and still more preferably 70 ° C to 105 ° C. The pressure is adjusted so that the solvent does not boil at the set temperature.

  Alternatively, a cooling dissolution method is also preferably used, whereby the cellulose ester can be dissolved in a solvent such as methyl acetate.

  Next, this cellulose ester solution is filtered using a suitable filter medium such as filter paper. As the filter medium, it is preferable that the absolute filtration accuracy is small in order to remove insoluble matters and the like. However, if the absolute filtration accuracy is too small, there is a problem that the filter medium is likely to be clogged. For this reason, a filter medium with an absolute filtration accuracy of 0.008 mm or less is preferable, a filter medium with 0.001 to 0.008 mm is more preferable, and a filter medium with 0.003 to 0.006 mm is more preferable.

  There are no particular restrictions on the material of the filter medium, and ordinary filter media can be used. However, plastic filter media such as polypropylene and Teflon (registered trademark), and metal filter media such as stainless steel do not drop off fibers. preferable. It is preferable to remove and reduce impurities, particularly bright spot foreign matter, contained in the raw material cellulose ester by filtration.

A bright spot foreign substance is when two polarizing plates are placed in a crossed Nicol state, a cellulose ester film is placed between them, light is applied from the side of one polarizing plate, and observed from the side of the other polarizing plate. It is a point (foreign matter) where light from the opposite side appears to leak, and the number of bright spots having a diameter of 0.01 mm or more is preferably 200 / cm ² or less. More preferably, it is 100 pieces / cm < ² > or less, More preferably, it is 50 pieces / m < ² > or less, More preferably, it is 0-10 pieces / cm < ² > or less. Further, it is preferable that the number of bright spots of 0.01 mm or less is small.

  The dope can be filtered by an ordinary method, but the method of filtering while heating at a temperature not lower than the boiling point of the solvent at normal pressure and in a range where the solvent does not boil under pressure is the filtration pressure before and after filtration. The increase in the difference (referred to as differential pressure) is small and preferable. A preferred temperature is 45 to 120 ° C, more preferably 45 to 70 ° C, and even more preferably 45 to 55 ° C.

  A smaller filtration pressure is preferred. The filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and further preferably 1.0 MPa or less.

  Here, the dope casting will be described.

  The metal support in the casting (casting) step preferably has a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support. The cast width can be 1 to 4 m. The surface temperature of the metal support in the casting step is set to −50 ° C. to a temperature at which the solvent boils and does not foam. A higher temperature is preferable because the web can be dried faster, but if it is too high, the web may foam or the flatness may deteriorate. A preferable support temperature is appropriately determined at 0 to 100 ° C, and more preferably 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent. The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing hot air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short. When using warm air, considering the temperature drop of the web due to the latent heat of vaporization of the solvent, while using warm air above the boiling point of the solvent, there may be cases where wind at a temperature higher than the target temperature is used while preventing foaming. . In particular, it is preferable to perform drying efficiently by changing the temperature of the support and the temperature of the drying air during the period from casting to peeling.

  In order for the cellulose ester film to exhibit good flatness, the residual solvent amount when peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass. Especially preferably, it is 20-30 mass% or 70-120 mass%.

  In the present invention, the amount of residual solvent is defined by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.

  Further, in the drying step of the cellulose ester film, the web is peeled off from the metal support, and further dried, and the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less, Especially preferably, it is 0-0.01 mass% or less.

  In the film drying process, generally, a roll drying method (a method in which a plurality of rolls arranged on the upper and lower sides are alternately passed through and dried) or a tenter method is used while drying the web.

  In order to produce the cellulose ester film for the antireflection film of the present invention, the web is stretched in the conveying direction where the residual solvent amount of the web immediately after peeling from the metal support is large, and both ends of the web are gripped with clips or the like. It is particularly preferable to perform stretching in the width direction by a tenter method. A preferable draw ratio in both the machine direction and the transverse direction is 1.05 to 1.3 times, and more preferably 1.05 to 1.15 times. It is preferable that the area is 1.12 to 1.44 times, and preferably 1.15 to 1.32 times due to longitudinal and lateral stretching. This can be determined by the draw ratio in the longitudinal direction × the draw ratio in the transverse direction. If one of the stretching ratios in the machine direction and the transverse direction is less than 1.05, the flatness deterioration due to ultraviolet irradiation when forming the hard coat layer is not preferable. Moreover, even if a draw ratio exceeds 1.3 times, since planarity deteriorates and haze also increases, it is not preferable.

  In order to stretch in the machine direction immediately after peeling, it is preferable to stretch by peeling tension and subsequent transport tension. For example, it is preferable to peel at a peeling tension of 210 N / m or more, and particularly preferably 220 to 300 N / m.

  The means for drying the web is not particularly limited, and can be generally performed with hot air, infrared rays, a heating roll, microwave, or the like, but is preferably performed with hot air in terms of simplicity.

  The drying temperature in the web drying step is preferably increased stepwise from 30 to 150 ° C, and more preferably from 50 to 140 ° C in order to improve dimensional stability.

  Although the film thickness of a cellulose-ester film is not specifically limited, 10-200 micrometers is used preferably. In particular, it was difficult to obtain an antireflection film excellent in flatness and hardness with a thin film of about 10 to 70 μm. However, according to the present invention, a thin antireflection film excellent in flatness and hardness can be obtained. Moreover, since it is excellent also in productivity, it is preferable that the film thickness of a cellulose-ester film is 10-70 micrometers. More preferably, it is 20-60 micrometers.

  Moreover, the cellulose ester film made into the multilayer structure by the co-casting method can also be used preferably. Even when the cellulose ester has a multilayer structure, it has a layer containing an ultraviolet absorber and a plasticizer, and it may be a core layer, a skin layer, or both.

  The antireflection film of the present invention preferably has a width of 1.4 to 5 m. Moreover, the centerline average roughness (Ra) of the surface which provides the hard-coat layer of a cellulose-ester film can use a 0.001-1 micrometer thing.

  When the width of the cellulose ester film becomes wider, the illuminance unevenness of the irradiated light during UV curing cannot be ignored, not only the flatness deteriorates, but also the hardness unevenness. When the antireflection layer is formed on this, the reflection unevenness There was a problem that became prominent. Since the antireflection film of the present invention can provide sufficient hardness with a small amount of irradiation, even if there is unevenness of the irradiation amount in the width direction of the irradiation light, unevenness of the hardness in the width direction is unlikely to occur, and the flatness is excellent. Since an antireflection film is obtained, a remarkable effect is recognized with a wide cellulose ester film. In particular, those having a width of 1.4 to 5 m are preferably used, and particularly preferably 1.4 to 3 m. If it exceeds 5 m, conveyance becomes difficult.

<Physical properties>
The moisture permeability of the cellulose ester film used in the present invention, 40 ° C., or less 850g / m ² · 24h at 90% RH, preferably ^{20~800g / m 2 · 24h, 20~750g} / m 2 · 24 h is particularly preferable. The moisture permeability can be measured according to the method described in JIS Z 0208.

  The cellulose ester film used in the present invention has a breaking elongation measured by the following measurement of preferably 10 to 80%, more preferably 20 to 50%.

(Measurement of elongation at break)
A film containing an arbitrary residual solvent is cut into a sample width of 10 mm and a length of 130 mm, and a sample stored for 24 hours at 23 ° C. and 55% RH is obtained by performing a tensile test at a pulling speed of 100 mm / min with a distance between chucks of 100 mm. I can do it.

  The visible light transmittance of the cellulose ester film used in the present invention as measured by the following measurement is preferably 90% or more, and more preferably 93% or more.

(Measurement of transmittance)
The transmittance T is 380, 400, 500 nm from the spectral transmittance τ (λ) obtained every 10 nm in the wavelength region of 350-700 nm using a spectral altimeter U-3400 (Hitachi, Ltd.). Transmittance can be calculated.

  The haze by the following measurement of the cellulose ester film used in the present invention is preferably less than 1%, particularly preferably 0 to 0.1%.

(Haze value)
According to JIS K-6714, it can be measured using a haze meter (1001DP type, manufactured by Nippon Denshoku Industries Co., Ltd.) and can be used as an index of transparency.

  The in-plane retardation value (Ro) of the cellulose ester film used in the present invention is preferably 0 to 70 nm or less. More preferably, it is 0-30 nm or less, More preferably, it is 0-10 nm or less. The retardation value (Rt) in the film thickness direction is preferably 0 to 400 nm, preferably 10 to 200 nm, and more preferably 30 to 150 nm.

  The retardation value (Ro) (Rt) can be obtained by the following equation.

Ro = (nx−ny) × d
Rt = ((nx + ny) / 2−nz) × d
Here, d is the thickness (nm) of the film, the refractive index nx (also referred to as the maximum refractive index in the plane of the film, the refractive index in the slow axis direction), ny (in the direction perpendicular to the slow axis in the film plane). ) (Refractive index of the film in the thickness direction).

  The retardation values (Ro) and (Rt) and the slow axis angle can be measured using an automatic birefringence meter. For example, the wavelength can be obtained at 590 nm in an environment of 23 ° C. and 55% RH using KOBRA-21ADH (Oji Scientific Instruments).

  The slow axis is preferably in the width direction ± 1 ° of the film or in the longitudinal direction ± 1 °.

  Next, a hard coat layer is applied on the surface of the cellulose ester film as a base material.

<Hard coat layer>
A method for coating a hard coat layer on the transparent support of the present invention will be described.

  The hard coat layer is a layer mainly composed of a resin that is cured through a crosslinking reaction or the like by irradiation with active rays such as ultraviolet rays or electron beams. As the hard coat layer, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and the hard coat layer is formed by curing by irradiating an active ray such as an ultraviolet ray or an electron beam. Typical examples of the hard coat layer include an ultraviolet curable resin and an electron beam curable resin, and a resin that is cured by ultraviolet irradiation is preferable.

  As the ultraviolet curable resin, for example, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, or an ultraviolet curable epoxy resin is preferable. Used. Of these, ultraviolet curable acrylate resins are preferred.

  The UV curable acrylic urethane resin generally includes 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter referred to as acrylate) in addition to a product obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer. It can be easily obtained by reacting an acrylate monomer having a hydroxyl group such as 2-hydroxypropyl acrylate. For example, those described in JP-A-59-151110 can be used.

  For example, a mixture of 100 parts Unidic 17-806 (Dainippon Ink Co., Ltd.) and 1 part Coronate L (Nihon Polyurethane Co., Ltd.) is preferably used.

  Examples of UV curable polyester acrylate resins include those that are easily formed when 2-hydroxyethyl acrylate and 2-hydroxy acrylate monomers are generally reacted with polyester polyols. JP-A-59-151112 Can be used.

  Specific examples of the ultraviolet curable epoxy acrylate resin include an epoxy acrylate as an oligomer, a reactive diluent and a photopolymerization initiator added thereto, and reacted to form an oligomer. The thing as described in 105738 can be used.

  Specific examples of UV curable polyol acrylate resins include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate, etc. I can list them.

  Specific examples of photopolymerization initiators for these ultraviolet curable resins include benzoin and its derivatives, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof. You may use with a photosensitizer. The photopolymerization initiator can also be used as a photosensitizer. When using an epoxy acrylate photopolymerization initiator, a sensitizer such as n-butylamine, triethylamine, or tri-n-butylphosphine can be used. The photopolymerization initiator or photosensitizer used in the ultraviolet curable resin composition is 0.1 to 15 parts by mass, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the composition.

  Examples of the resin monomer include general monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, cyclohexyl acrylate, vinyl acetate, and styrene as monomers having one unsaturated double bond. In addition, monomers having two or more unsaturated double bonds include ethylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, 1,4-cyclohexane diacrylate, 1,4-cyclohexyldimethyl adiacrylate, and the above trimethylolpropane. Examples thereof include triacrylate and pentaerythritol tetraacryl ester.

  Commercially available UV curable resins that can be used in the present invention include ADEKA OPTMER KR / BY series: KR-400, KR-410, KR-550, KR-566, KR-567, BY-320B (Asahi Denka ( Co., Ltd.); Koeihard A-101-KK, A-101-WS, C-302, C-401-N, C-501, M-101, M-102, T-102, D-102, NS -101, FT-102Q8, MAG-1-P20, AG-106, M-101-C (manufactured by Guangei Chemical Co., Ltd.); Seica Beam PHC2210 (S), PHC X-9 (K-3), PHC2213, DP -10, DP-20, DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, SCR900 (manufactured by Dainichi Seika Kogyo Co., Ltd.) KRM7033, KRM7039, KRM7130, KRM7131, UVECRYL29201, UVECRYL29202 (manufactured by Daicel UCB); RC-5015, RC-5016, RC-5020, RC-5031, RC-5100, RC-5102, RC-5120 RC-5122, RC-5152, RC-5171, RC-5180, RC-5181 (manufactured by Dainippon Ink & Chemicals, Inc.); 340 clear (manufactured by China Paint Co., Ltd.); Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (Sanyo Chemical Industries, Ltd.); SP -1509, SP-1507 (manufactured by Showa Polymer Co., Ltd.); RCC-15C (manufactured by Grace Japan Co., Ltd.), Aronix M-6100, M-8030, M-8060 (manufactured by Toagosei Co., Ltd.), etc. Can be selected as appropriate.

  Specific examples of compounds include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate, and the like. .

  The cured resin layer thus obtained may contain fine particles of an inorganic compound or an organic compound in order to adjust the scratch resistance, slipperiness and refractive index, and to impart antiglare properties to the produced antireflection film.

  Examples of inorganic fine particles used in the hard coat layer include silicon oxide, titanium oxide, aluminum oxide, tin oxide, indium oxide, ITO, zinc oxide, zirconium oxide, magnesium oxide, calcium carbonate, calcium carbonate, talc, clay, and calcined kaolin. And calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. In particular, silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide and the like are preferably used.

  Organic particles include polymethacrylic acid methyl acrylate resin powder, acrylic styrene resin powder, polymethyl methacrylate resin powder, silicon resin powder, polystyrene resin powder, polycarbonate resin powder, benzoguanamine resin powder, melamine resin powder. Polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, or polyfluoroethylene resin powder can be added to the ultraviolet curable resin composition. Particularly preferred are cross-linked polystyrene particles (for example, SX-130H, SX-200H, SX-350H, manufactured by Soken Chemical) and polymethyl methacrylate-based particles (for example, MX150, MX300, manufactured by Soken Chemical).

  The average particle size of these fine particle powders is preferably 0.01 to 5 μm, more preferably 0.1 to 5.0 μm, and particularly preferably 0.1 to 4.0 μm. Moreover, it is preferable to contain 2 or more types of microparticles | fine-particles from which a particle size differs. The proportion of the ultraviolet curable resin composition and the fine particles is desirably blended so as to be 0.1 to 30 parts by mass with respect to 100 parts by mass of the resin composition.

  The UV curable resin layer is a hard coat layer having a center line average roughness (Ra) defined by JIS B 0601 of 0.001 to 0.1 μm, or an antiglare layer having Ra of about 0.1 to 1 μm. It is preferable that The center line average roughness (Ra) is preferably measured with an optical interference type surface roughness measuring instrument, and can be measured using, for example, a non-contact surface fine shape measuring device WYKO NT-2000 manufactured by WYKO.

(Refractive index of hard coat layer)
The refractive index of the hard coat layer according to the present invention is preferably from 1.5 to 2.0, particularly from 1.6 to 1.7 from the viewpoint of optical design for obtaining a low reflective film. The refractive index of the hard coat layer can be adjusted depending on the refractive index and content of the fine particles or inorganic binder to be added.

(Hard coat layer thickness)
From the viewpoint of imparting sufficient durability and impact resistance, the thickness of the hard coat layer is preferably 0.5 to 15 μm, more preferably 1 to 10 μm.

  These hard coat layers can be coated by a known method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, or an ink jet method. After application, it is heat-dried and UV-cured.

As a light source for curing an ultraviolet curable resin by a photocuring reaction to form a cured film layer, any light source that generates ultraviolet rays can be used without any limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. The irradiation conditions vary depending on individual lamps, irradiation of actinic rays is usually 5~500mJ / cm ^2, but is preferably 5 to 100 mJ / cm ^2, particularly preferably 20~80mJ / cm ^2.

  In the conventional antireflection film, an antireflection film having a pencil hardness of 4H or more and excellent flatness cannot be obtained at such a low irradiation amount. In the case of an antireflection film that does not require much hardness, the amount of irradiation can be further reduced, so that the antireflection film can be produced at a speed far exceeding the coating speed limited by the ability of the UV irradiation section, and the productivity Is significantly improved. In addition, when adding inorganic fine particles or an inorganic binder to the hard coat layer to increase the refractive index or impart conductivity, it has been necessary to significantly increase the amount of ultraviolet irradiation in the past, causing deterioration in film flatness. It became one of. In particular, in a wide film with a width of 1.4 to 5 m and a thin film with a film thickness of 20 to 60 μm, the flatness deterioration was remarkable, but the present invention can reduce the conventional irradiation amount, and the flatness An excellent antireflection film can be obtained.

  Moreover, when irradiating actinic radiation, it is preferable to carry out while applying tension | tensile_strength in the conveyance direction of a film, More preferably, it is performing applying tension | tensile_strength also in the width direction. The tension to be applied is preferably 30 to 300 N / m. The method for applying tension is not particularly limited, and tension may be applied in the transport direction on the back roll, or tension may be applied in the width direction or biaxial direction by a tenter. This makes it possible to obtain a film having further excellent flatness.

  The ultraviolet curable resin layer composition coating solution may contain a solvent, or may be appropriately contained and diluted as necessary. Examples of the organic solvent contained in the coating solution include hydrocarbons (toluene, xylene), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone), It can be appropriately selected from esters (methyl acetate, ethyl acetate, methyl lactate), glycol ethers, and other organic solvents, or a mixture thereof can be used. Propylene glycol monoalkyl ether (1 to 4 carbon atoms of the alkyl group) or propylene glycol monoalkyl ether acetate ester (1 to 4 carbon atoms of the alkyl group) is 5% by mass or more, more preferably 5 to 80%. It is preferable to use the organic solvent containing at least mass%.

  In addition, it is particularly preferable to add a silicon compound to the ultraviolet curable resin layer composition coating solution. For example, polyether-modified silicone oil is preferably added. The number average molecular weight of the polyether-modified silicone oil is, for example, 1000 to 100000, preferably 2000 to 50000. If the number average molecular weight is less than 1000, the drying property of the coating film decreases, and conversely, the number average When the molecular weight exceeds 100,000, it tends to be difficult to bleed out to the coating surface.

  Commercially available silicon compounds include DKQ8-779 (trade name, manufactured by Dow Corning), SF3771, SF8410, SF8411, SF8419, SF8421, SF8428, SH200, SH510, SH1107, SH3749, SH3771, BX16-034, SH3746, SH3749, SH8400, SH3771M, SH3772M, SH3773M, SH3775M, BY-16-837, BY-16-839, BY-16-869, BY-16-870, BY-16-004, BY-16-891, BY-16 872, BY-16-874, BY22-008M, BY22-012M, FS-1265 (above, product names manufactured by Toray Dow Corning Silicone), KF-101, KF-100T, KF351, KF3 2, KF353, KF354, KF355, KF615, KF618, KF945, KF6004, Silicone X-22-945, X22-160AS (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), XF3940, XF3949 (trade name, manufactured by Toshiba Silicone Co., Ltd.) ), Disparon LS-009 (manufactured by Enomoto Kasei Co., Ltd.), Granol 410 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.), TSF4440, TSF4441, TSF4445, TSF4446, TSF4452, TSF4460 (manufactured by GE Toshiba Silicone), BYK-306, BYK- 330, BYK-307, BYK-341, BYK-344, BYK-361 (manufactured by BYK-Japan) L series (for example, L7001, L-7006, L-7604, L-9000) manufactured by Nippon Unicar Co., Ltd. Y Over's, FZ series (FZ-2203, FZ-2206, FZ-2207) and the like, it is preferably used.

  These components enhance the applicability to the substrate and the lower layer. When added to the outermost surface layer of the laminate, it not only improves the water repellency, oil repellency and antifouling properties of the coating film, but also exhibits an effect on the scratch resistance of the surface. These components are preferably added in a range of 0.01 to 3% by mass with respect to the solid component in the coating solution.

  The hard coat layer of the present invention may contain conductive metal oxide fine particles. The conductive metal oxide fine particles are preferably metal oxide fine particles selected from Zr, Sn, Sb, As, Zn, Nb, In, and Al. Specifically, aluminum oxide, tin oxide, and indium oxide. , ITO, zinc oxide, and aluminum silicate. In particular, ITO or the like is preferably used.

  The hard coat layer is a clear hard coat layer having a center line average roughness (Ra) defined by JIS B 0601 of 0.001 to 0.1 μm, or an antiglare hard coat layer having Ra of 0.1 to 1 μm. Is preferred. The center line average roughness (Ra) is preferably measured with an optical interference type surface roughness measuring instrument, and can be measured using, for example, a non-contact surface fine shape measuring device WYKO NT-2000 manufactured by WYKO.

  The refractive index on the antireflection layer side in the case where the hard coat layer according to the present invention is composed of two or more layers and the optical interference antireflection layer is laminated has a refractive index of 1 from the viewpoint of optical design for obtaining a low reflection film. It is preferable that it is .57-2.00. The refractive index of the hard coat layer can be adjusted depending on the refractive index and content of the fine particles or inorganic binder to be added. For increasing the refractive index, Ti, Zr, Sn, Sb, As, Zn, Nb, In, and Al are used. The selected metal oxide fine particles are preferred.

<Back coat layer>
It is preferable to provide a backcoat layer on the surface opposite to the side on which the hard coat layer is provided of the cellulose ester film that is the base material for producing the antireflection film of the present invention. The back coat layer is provided in order to correct curling caused by providing a hard coat layer or other layers. That is, the degree of curling can be balanced by imparting the property of being rounded with the surface on which the backcoat layer is provided facing inward. The back coat layer is preferably applied also as an anti-blocking layer. In that case, it is preferable that fine particles are added to the back coat layer coating composition in order to provide an anti-blocking function.

  As fine particles added to the back coat layer, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, tin oxide, and oxidation. Mention may be made of indium, zinc oxide, ITO, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. Fine particles containing silicon are preferable in terms of low haze, and silicon dioxide is particularly preferable.

  These fine particles are commercially available under the trade names of, for example, Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, and TT600 (manufactured by Nippon Aerosil Co., Ltd.). . Zirconium oxide fine particles are commercially available under the trade names of Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used. Examples of the polymer include silicone resin, fluorine resin, and acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.) It is marketed by name and can be used.

  Among these, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large anti-blocking effect while keeping haze low. The antireflection film used in the present invention preferably has a coefficient of dynamic friction on the back side of the hard coat layer of 0.9 or less, particularly 0.1 to 0.9.

  The fine particles contained in the backcoat layer are 0.1 to 50% by weight, preferably 0.1 to 10% by weight, based on the binder. When the back coat layer is provided, the increase in haze is preferably 1% or less, more preferably 0.5% or less, and particularly preferably 0.0 to 0.1%.

  Specifically, the back coat layer is formed by applying a composition containing a solvent for dissolving or swelling a cellulose ester film. The solvent to be used may include a solvent to be dissolved and / or a solvent to be swollen in addition to a solvent to be dissolved, a composition in which these are mixed at an appropriate ratio depending on the curl degree of the transparent resin film and the type of the resin, and This is done using the coating amount.

  In order to enhance the curl prevention function, it is effective to increase the mixing ratio of the solvent for dissolving the solvent composition to be used and / or the solvent for swelling, and to decrease the ratio of the solvent not to be dissolved. This mixing ratio is preferably (solvent to be dissolved and / or solvent to be swollen) :( solvent to be dissolved) = 10: 0 to 1: 9. Examples of the solvent for dissolving or swelling the transparent resin film contained in such a mixed composition include dioxane, acetone, methyl ethyl ketone, N, N-dimethylformamide, methyl acetate, ethyl acetate, trichloroethylene, methylene chloride, and ethylene chloride. , Tetrachloroethane, trichloroethane, chloroform and the like. Examples of the solvent that does not dissolve include methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butanol, cyclohexanol, and hydrocarbons (toluene, xylene).

  These coating compositions are preferably applied to the surface of the transparent resin film with a wet film thickness of 1 to 100 μm using a gravure coater, dip coater, reverse coater, wire bar coater, die coater, spray coating, ink jet coating or the like. Is particularly preferably 5 to 30 μm. Examples of the resin used as the binder of the backcoat layer include vinyl chloride-vinyl acetate copolymer, vinyl chloride resin, vinyl acetate resin, vinyl acetate-vinyl alcohol copolymer, partially hydrolyzed vinyl chloride-vinyl acetate copolymer. Polymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, ethylene-vinyl alcohol copolymer, chlorinated polyvinyl chloride, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, etc. Vinyl polymer or copolymer, nitrocellulose, cellulose acetate propionate (preferably acetyl group substitution degree 1.8-2.3, propionyl group substitution degree 0.1-1.0), diacetyl cellulose, cellulose Cellulose derivatives such as acetate butyrate resin, maleic acid and / or Or acrylic acid copolymer, acrylic ester copolymer, acrylonitrile-styrene copolymer, chlorinated polyethylene, acrylonitrile-chlorinated polyethylene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, acrylic resin Rubber resins such as polyvinyl acetal resin, polyvinyl butyral resin, polyester polyurethane resin, polyether polyurethane resin, polycarbonate polyurethane resin, polyester resin, polyether resin, polyamide resin, amino resin, styrene-butadiene resin, butadiene-acrylonitrile resin, Examples thereof include, but are not limited to, silicone resins and fluorine resins. For example, as an acrylic resin, Acrypet MD, VH, MF, V (manufactured by Mitsubishi Rayon Co., Ltd.), Hyperl M-4003, M-4005, M-4006, M-4202, M-5000, M-5001, M-4501 (manufactured by Negami Kogyo Co., Ltd.), Dialnal BR-50, BR-52, BR-53, BR-60, BR-64, BR-73, BR-75, BR-77, BR-79, BR -80, BR-82, BR-83, BR-85, BR-87, BR-88, BR-90, BR-93, BR-95, BR-100, BR-101, BR-102, BR-105 BR-106, BR-107, BR-108, BR-112, BR-113, BR-115, BR-116, BR-117, BR-118, etc. (Mitsubishi Rayon Co., Ltd.) acrylic and The methacrylic monomers are commercially available various homopolymers and copolymers, etc. was prepared as a raw material, it is also possible to select the preferred mono from this appropriate.

  Particularly preferred are cellulose resin layers such as diacetylcellulose and cellulose acetate propionate.

  The order of coating the back coat layer may be before or after the hard coat layer of the cellulose ester film is coated, but when the back coat layer also serves as an anti-blocking layer, it is preferably coated first. Alternatively, the backcoat layer can be applied in two or more steps.

<Polarizer>
The polarizing plate of the present invention will be described.

  The polarizing plate can be produced by a general method. The back surface side of the antireflection film of the present invention is subjected to alkali saponification treatment, and a completely saponified polyvinyl alcohol aqueous solution is used on at least one surface of a polarizing film prepared by immersing and stretching the treated antireflection film in an iodine solution. It is preferable to bond them together. The antireflection film may be used on the other surface, or another polarizing plate protective film may be used. In contrast to the antireflection film of the present invention, the polarizing plate protective film used on the other surface has an in-plane retardation Ro of 590 nm, an optical compensation having a phase difference of 20 to 70 nm and Rt of 100 to 400 nm. A film is preferred. These can be produced, for example, by the method described in JP-A-2002-71957 and Japanese Patent Application No. 2002-155395. Alternatively, it is preferable to use a polarizing plate protective film that also serves as an optical compensation film having an optically anisotropic layer formed by aligning a liquid crystal compound such as a discotic liquid crystal. For example, the optically anisotropic layer can be formed by the method described in JP-A-2003-98348. By using it in combination with the antireflection film of the present invention, a polarizing plate having excellent flatness and a stable viewing angle expansion effect can be obtained.

  As the polarizing plate protective film used on the back side, KC8UX2MW, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3 (manufactured by Konica Minolta Opto Co., Ltd.) and the like are also preferably used as commercially available cellulose ester films.

  The polarizing film, which is the main component of the polarizing plate, is an element that transmits only light having a polarization plane in a certain direction. A typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol film. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed. As the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxially stretching or dyed, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound. On the surface of the polarizing film, one side of the antireflection film of the present invention is bonded to form a polarizing plate. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.

  A conventional polarizing plate using an antireflection film is inferior in flatness, and when a reflected image is seen, a fine wavy unevenness is recognized, and a pencil hardness of only about 2H is obtained, under conditions of 60 ° C. and 90% RH. As a result of the durability test, the wavy unevenness increased. On the other hand, the polarizing plate using the antireflection film of the present invention has excellent antireflection performance, excellent flatness, and excellent pencil hardness of 3H or more. Yes. In addition, even in a durability test under the conditions of 60 ° C. and 90% RH, the wavy unevenness does not increase, and even with a polarizing plate having an optical compensation film on the back side, viewing angle characteristics after the durability test It was possible to provide good viewing angle characteristics without fluctuation.

<Display device>
By incorporating the polarizing plate of the present invention into a display device, the display device of the present invention having various visibility can be manufactured. The antireflection film of the present invention is a reflective type, transmissive type, transflective type LCD or TN type, STN type, OCB type, HAN type, VA type (PVA type, MVA type), IPS type, etc. Preferably used. In addition, the antireflection film of the present invention has significantly less color unevenness in the reflected light of the antireflection layer, and has a low reflectance and excellent flatness, and is a plasma display, field emission display, organic EL display, inorganic EL display, electronic It is also preferably used for various display devices such as paper. In particular, a large-screen display device with a 30-inch screen or more has the effect of less color unevenness and wavy unevenness, and eyes are not tired even during long-time viewing.

  The backlight of the liquid crystal display device is preferably a direct backlight type. Specific examples of the direct backlight system include the following.

(1) Japanese Patent Application Laid-Open No. 2001-215497 On a display screen due to variation in the position of fluorescent tubes in a backlight device of a large-sized liquid crystal display panel by forming a fluorescent tube arrangement positioning portion and / or a fluorescent tube support portion and a reflecting plate by integral molding. Brightness unevenness is improved, and the backlight structure is simplified.

(2) Japanese Patent Application Laid-Open No. 2001-305535 In a direct type backlight that is placed under a transmissive liquid crystal display device and irradiates light to the transmissive liquid crystal display device, the direct type backlight includes at least a circuit board, a light emitting element, and a pyramid shape. And a light emitting surface (diffusion sheet). The pyramidal hole has a shape that extends from the light emitting element toward the light emitting surface and has a structure that expands in a stepped manner, and is opposed to the diffusion sheet. In the light emitting surface of a direct type backlight using a point light source such as an LED, and having a reflective surface having a curvature that reflects the primary reflected light from the central part of the diffusion sheet to the peripheral edge of the diffusion sheet Reduce brightness unevenness.

(3) Japanese Patent Application Laid-Open No. 2003-215585 A direct type backlight body includes a plurality of fluorescent tubes arranged side by side, a housing that houses these fluorescent tubes, and a diffusion plate that is disposed so as to cover an opening of the housing Consists of. Then, a plurality of ribs are integrally formed on the lower surface of the diffusion plate made of translucent resin. Note that these ribs provided on the lower surface of the diffusion plate are linear protrusions parallel to the longitudinal direction of the diffusion plate. Thereby, the intensity | strength of the longitudinal direction of a diffusion plate can go up and the curvature of a diffusion plate can be prevented.

(4) JP 2004-29091 A total of 100 parts by mass of 99.7 to 80% by mass of polycarbonate resin and 0.3 to 20% by mass of transparent fine particles having an average particle diameter of 1 to 30 μm and 0.005 to 0 of a fluorescent brightening agent With a light diffusion plate for direct-type backlight made of polycarbonate resin having a thickness of 0.5 to 3.0 mm formed from a resin composition consisting of 1 part by mass, it has excellent surface luminescence and little luminance unevenness, In addition, it is possible to provide a light diffusion plate made of polycarbonate resin having an excellent color tone, particularly a light diffusion plate made of polycarbonate resin suitable for a direct type backlight system of a large liquid crystal display or a large liquid crystal television.

(5) Japanese Patent Application Laid-Open No. 2004-102119 A reflector for direct type backlight arranged behind a plurality of straight tube type light sources for illuminating a liquid crystal display panel and reflecting light from the light sources to the liquid crystal display panel side Then, by forming a polycarbonate resin sheet having a thickness of 0.6 to 1.5 mm by matched die molding, a plurality of peak portions are formed in parallel at an equal pitch, and the bottom portion 12 is formed between the peak portions. It is formed and the light source is arranged at a position directly above the center of the bottom, and it is easy to increase the size, and even if the size is increased, there is almost no local luminance unevenness due to deformation and excellent reflection performance. A reflector for a direct backlight of a liquid crystal display device can be provided.

  In particular, in the liquid crystal display device using the polarizing plate of the present invention, the present invention is effective for a thin liquid crystal display device having a size of 15 inches or more and having a large influence of heat with a short distance between the light source and the polarizing plate.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1
[Production of Cellulose Ester Film 1]
A cellulose ester solution (dope) was prepared using the cellulose ester, plasticizer, ultraviolet absorber, fine particles, and solvent shown below, and a cellulose ester film 1 was prepared by a solution casting film forming method.
Cellulose ester;
Cellulose triacetate 100kg
(Acetyl group substitution degree 2.9 Mn = 16000 Mw / Mn = 1.8)
Plasticizers;
Trimethylolpropane tribenzoate 5kg
Ethyl phthalyl ethyl glycolate 5kg
UV absorbers;
Tinuvin 109 (Ciba Specialty Chemicals Co., Ltd.) 1.0kg
Tinuvin 171 (Ciba Specialty Chemicals Co., Ltd.) 1.0kg
Fine particles;
Aerosil R972V (Nippon Aerosil Co., Ltd.) 0.3kg
solvent;
440 kg of methylene chloride
110 kg of ethanol
A cellulose ester solution (dope) was prepared using the above cellulose ester, plasticizer, ultraviolet absorber, fine particles, and solvent.

  That is, the solvent was put into an airtight container, the remaining materials were put in order with stirring, and completely dissolved and mixed while heating and stirring. The fine particles were added dispersed in a part of the solvent. After the temperature was lowered to the temperature at which the solution was cast and allowed to stand overnight, a defoaming operation was performed, and then the solution was Azumi Filter Paper No. Filtration using 244 gave a cellulose ester solution.

  Next, the cellulose ester solution whose temperature was adjusted to 33 ° C. was fed to a die and uniformly cast from a die slit onto a stainless steel belt. The cast part of the stainless steel belt was heated from the back with hot water of 37 ° C. After casting, the dope film on the metal support (which is called a web after casting on the stainless steel belt) is dried by applying hot air of 44 ° C., and the residual solvent in the peeling is peeled off at 120 mass%. The web end is gripped with a tenter while the residual solvent amount is from 35% by mass to 10% by mass, and is stretched in the width direction. It extended | stretched so that it might become 1.1 times the draw ratio. After stretching, the width is maintained for several seconds, then the tension in the width direction is relaxed, then the width is released, and further transported for 20 minutes in the third drying zone set at 125 ° C. for drying. The cellulose ester film 1 having a width of 1.5 m and a film thickness of 80 μm was produced.

[Coating of hard coat layer and back coat layer]
On the cellulose ester film 1, the following hard coat layer coating solution is filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a hard coat layer coating solution, which is applied using a micro gravure coater, and 100 After drying at a temperature of 1 ° C. for 1 minute, the coating layer is cured using an ultraviolet lamp with an irradiance of 100 mW / cm ² and an irradiation amount of 0.1 J / cm ² to form a hard coat layer having a dry film thickness of 10 μm. A hard coat film was produced.

(Hard coat layer coating solution)
The following materials were stirred and mixed to obtain a hard coat layer coating solution.

Acrylic monomer: KAYARAD DPHA (dipentaerythritol hexaacrylate, Nippon Kayaku) 220 parts by mass Irgacure 184 (manufactured by Ciba Specialty Chemicals) 20 parts by mass Propylene glycol monomethyl ether 110 parts by mass Ethyl acetate 110 parts by mass The coat layer composition was applied by an extrusion coater so as to have a wet film thickness of 10 μm, and dried at 85 ° C. to provide a back coat layer.

(Backcoat layer composition)
Acetone 54 parts by weight Methyl ethyl ketone 24 parts by weight Methanol 22 parts by weight Diacetylcellulose 0.6 part by weight Ultrafine silica 2% acetone dispersion (Aerosil 200V manufactured by Nippon Aerosil Co., Ltd.)
0.2 parts by mass [Preparation of antireflection film]
On the hard coat film produced as described above, an antireflection layer was applied in the order of a high refractive index layer and then a low refractive index layer as described below, and antireflection films 1 to 14 were produced.

(Refractive index)
The refractive index of each refractive index layer was calculated | required from the measurement result of the spectral reflectance of a spectrophotometer about the sample which coated each layer on the hard coat film produced above independently. The spectrophotometer uses U-4000 type (manufactured by Hitachi, Ltd.), and after roughening the back side of the measurement side of the sample, light absorption treatment is performed with black spray to prevent reflection of light on the back side. The reflectance in the visible light region (400 nm to 700 nm) was measured under the condition of regular reflection at 5 degrees.

(Preparation of antireflection layer: high refractive index layer)
On the hard coat film, the following high refractive index layer coating composition was coated with an extrusion coater, dried at 80 ° C. for 1 minute, then cured by irradiation with ultraviolet rays of 0.1 J / cm ² , and further at 100 ° C. for 1 Partial drying was performed, and a high refractive index layer was provided so as to have a thickness of 78 nm.

  The refractive index of this high refractive index layer was 1.62.

<High refractive index layer coating composition>
<Preparation of liquid A>
To 37 parts by mass of zinc antimonate fine particle dispersion (CELNAX CX-Z610M-F2, manufactured by Nissan Chemical Industries, Ltd., solvent MeOH solid content 60%), 100 parts by mass of isopropyl alcohol was added dropwise with stirring.

  Next, a B liquid having the following composition was prepared and added to the A liquid while slowly stirring to prepare a high refractive index layer coating composition.

<Preparation of liquid B>
Isopropyl alcohol 473 parts by mass Propylene glycol monomethyl ether 287 parts by mass Methyl ethyl ketone 96 parts by mass Dipentaerythritol hexaacrylate (KYARAD DPHA made by Nippon Kayaku) 7.4 parts by mass Photopolymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals)
11.5 parts by mass Photopolymerization initiator (Irgacure 907 manufactured by Ciba Specialty Chemicals)
4.9 parts by mass Leveling agent (FZ2222 made by Nippon Unicar) 0.3 parts by mass (Preparation of antireflection layer: low refractive index layer)
The high refractive index layer was coated by coater extrusion a low refractive index layer coating composition 1 below, after drying 1 minute at 100 ° C., ultraviolet rays and cured 0.1 J / cm ² irradiation to further The film was dried at 100 ° C. for 5 minutes, a low refractive index layer was provided so as to have a thickness of 95 nm, and an antireflection film 1 was produced. The refractive index of this low refractive index layer was 1.36.

(Preparation of low refractive index layer coating composition 1)
<Preparation of tetraethoxysilane hydrolyzate A>
Tetraethoxysilane 28.9 parts by mass Ethanol 55.3 parts by mass Acetic acid 2.6 parts by mass Pure water 13.2 parts by mass Tetraethoxysilane hydrolyzate A by stirring the above material in a 25 ° C water bath for 30 hours. Was prepared.

<Low refractive index layer coating composition 1>
Tetraethoxysilane hydrolyzate A 67.5 parts by mass KBM503 (silane coupling agent, manufactured by Shin-Etsu Chemical Co., Ltd.) 4.7 parts by mass Compound A 5.8 parts by mass Hollow silica fine particle dispersion (ELCOM K0-1001 SIV catalytic chemistry Manufactured solvent isopropyl alcohol, methanol solid content 20%) 19.3 parts by mass Propylene glycol monomethyl ether (PGME) 450 parts by mass Isopropyl alcohol (IPA) 450 parts by mass [heat treatment of antireflection film]
The produced antireflection film 1 was wound into a roll and subjected to heat treatment at 80 ° C. for 3 days in a heat treatment chamber.

  Similarly to the production of the antireflection film 1, the low refractive index layer coating composition 1 was changed to the low refractive index coating composition described in Table 1 below, and antireflection films 2 to 14 were produced.

  The compounds described in Table 1 are as follows.

Compound _{A: C 3 F 7 - (} OC 3 F 6) 24 -O- (CF 2) 2 -C 2 H 4 -O-CH 2 Si (OCH 3) 3
Compound B: Heptadecafluorodecyltrimethoxysilane Leveling agent FZ2222: Nihon Unicar 10% propylene glycol monomethyl ether solution Surfactant C1: Fluorosurfactant (Neos Co., Ltd., Footent 250)
Surfactant C2: Polydimethylsiloxane (Shin-Etsu Chemical KF-96-1000CS)
Surfactant C3: polydimethylsiloxane (Shin-Etsu Chemical KF-96-500CS)
Surfactant C4: Polydimethylsiloxane (Shin-Etsu Chemical KF-96-100CS)
Surfactant C5: Polydimethylsiloxane (Shin-Etsu Chemical KF-96-10CS)
Surfactant C6: Polydimethylsiloxane (manufactured by Shin-Etsu Chemical KF-96L-5CS)
Surfactant C7: Polydimethylsiloxane (Shin-Etsu Chemical KF-96L-2CS)
Surfactant C8: Carbinol-modified silicone oil at both ends (KF-6001 manufactured by Shin-Etsu Chemical)
Surfactant C9: Carbinol modified silicone oil at both ends (KF-6002 manufactured by Shin-Etsu Chemical)
Surfactant C10: Hydroxy modified silicone oil at both ends (YF-3800 manufactured by GE Toshiba Silicone)
<Viscosity of surfactant>
Each solution was adjusted to a temperature of 25 ° C. and measured using VISCO MATE MODEL VM-1A manufactured by Yamaichi Denki Co., Ltd., which was verified with a viscometer calibration standard solution defined in JIS Z 8809.

[Evaluation]
<Pencil hardness>
Using pencils with different hardnesses, a hardness test was performed based on the test method shown in JIS K5400 under a load of 1 kg. Each antiglare antireflection film was divided into 10 in the width direction, and the pencil hardness at each position was measured.

<Magic resistance>
Write a line with black oil-based magic (ZEBRA's Mackey extra fine) on the anti-reflection film, and wipe the line with Bencotton (Asahi Kasei Co., Ltd.) (within a pressure of 1.0 kg / cm ² , within 5 reciprocations) ), If it can be wiped off, write the line again with the magic at the place where the magic line was written, and check whether it can be wiped off. This operation is repeated, and the number of times that it can be written and wiped with a magic pen is taken as the value of magic resistance.

  Further, after the antireflection film was placed in a temperature controller set at 40 ° C. for 3 days, the same test was conducted.

  The structure of the low refractive index layer of the antireflection film and the evaluation results are shown in Table 1 below.

  The antireflective films 6 to 14 having the configuration of the low refractive index layer according to the present invention and the magic resistance satisfying the provisions of the present invention have a low refractive index of 1.38 to 1.39 and a pencil. It is clear that the hardness is 2H or more, and it is an antireflection film that is excellent in antifouling property, which is an object of the present invention, and that achieves both low refractive index and high pencil hardness.

Example 2
[Production of Cellulose Ester Film 2]
A cellulose ester film 2 was produced in the same manner as in Example 1 except that the film thickness was changed to 40 μm.

[Coating of hard coat layer and back coat layer]
Using the cellulose ester film 2, the following hard coat layer coating solution is filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a hard coat layer coating solution, which is applied using a micro gravure coater, After drying for 1 minute at the temperature shown in Table 2, using an ultraviolet lamp, the irradiance of the irradiated part is 100 mW / cm ² , the irradiation amount is 0.1 J / cm ² , the coating layer is cured, and the hard coat has a dry film thickness of 10 μm. A layer was formed to prepare a hard coat film.

(Hard coat layer coating solution)
The following materials were stirred and mixed to obtain a hard coat layer coating solution.

UV curable resin (NK Hard B-420, manufactured by Shin-Nakamura Chemical Co., Ltd.) 55 parts by mass Acetone 27 parts by mass Methyl isobutyl ketone 9 parts by mass Cyclohexanone 9 parts by mass Next, on the side opposite to the side coated with the hard coat layer, Examples A back coat layer was provided in the same manner as in 1.

[Preparation of antireflection film]
On the hard coat film prepared above, an antireflection layer was applied in the order of a high refractive index layer and then a low refractive index layer as described below to prepare antireflection films 15 to 19.

(Preparation of antireflection layer: high refractive index layer)
A high refractive index layer was provided in the same manner as in Example 1 except that the drying temperature after application of the high refractive index layer was changed as shown in Table 2.

(Preparation of antireflection layer: low refractive index layer)
After providing a low refractive index layer in the same manner as the antireflection film 13 of Example 1, the film was dried at the drying temperature shown in Table 2, and the prepared antireflection film was wound into a roll and heated to 70 ° C. in a heat treatment chamber. Were subjected to heat treatment for 5 days to produce antireflection films 15 to 19.

[Evaluation]
<Flatness>
Laser displacement meter: Keyence Corporation, Model: LT-8100, Resolution: 0.2 μm, Scan with laser displacement meter in width direction to measure fine undulations on surface, anti-glare antireflection film The flatness of was evaluated.

  The measuring method is to place the film on a flat and horizontal table, fix both ends of the width to the table with tape, and set the measuring camera parallel to the table. It set so that the space | interval of a sample film might be set to 25 mm, and it scanned and measured with the moving speed of 5 cm / min. The measurement was performed from the back side provided with an antireflection layer in order to observe deformation such as undulation of the film itself. The value obtained by the measurement is the state and size of minute irregularities on the film. The smaller the unevenness due to the deformation of the film, the better the flatness.

◎: Unevenness due to film deformation is less than 1.0 ○: Unevenness due to film deformation is less than 1.0 to 2.0 μm Δ: Unevenness due to film deformation is less than 2.0 to 4.0 μm ×: Due to film deformation The unevenness is 4.0 μm or more. Besides, magic resistance and pencil hardness were evaluated in the same manner as in Example 1.

  The obtained results are shown in Table 2 below.

  Comparing the antireflection films 15 to 19 of the present invention, the flatness and pencil hardness are further improved while maintaining the antifouling property by lowering the drying temperature of the hard coat layer, the high refractive index layer and the low refractive index layer. It can be seen that it is improved.

Example 3
In accordance with the following method, polarizing plates 1 to 19 were prepared using the antireflection films 1 to 19 and a cellulose ester optical compensation film KC8UCR-5 (manufactured by Konica Minolta Opto Co., Ltd.) each as a polarizing plate protective film. Produced.

(A) Production of polarizing film 100 parts by mass of polyvinyl alcohol (hereinafter abbreviated as PVA) having a saponification degree of 99.95 mol% and a polymerization degree of 2400 was melt-kneaded with 10 parts by mass of glycerin and 170 parts by mass of water. After defoaming, the film was melt extruded from a T die onto a metal roll to form a film. Then, it dried and heat-processed and obtained the PVA film. The obtained PVA film had an average thickness of 40 μm, a moisture content of 4.4%, and a film width of 3 m.

  The aforementioned PVA film was processed in the order of pre-swelling, dyeing, uniaxial stretching by a wet method, fixing treatment, drying, and heat treatment to produce a polarizing film. The PVA film was pre-swelled by immersing it in water at 30 ° C. for 30 seconds and immersed in an aqueous solution at 35 ° C. having an iodine concentration of 0.4 g / liter and a potassium iodide concentration of 40 g / liter for 3 minutes. Subsequently, the film was uniaxially stretched 6 times in an aqueous solution of boric acid concentration 4% at 50 ° C. under a tension of 700 N / m. The potassium iodide concentration 40 g / liter, boric acid concentration 40 g / liter, Fixation was performed by immersing in an aqueous solution at 30 ° C. with a zinc chloride concentration of 10 g / liter for 5 minutes. Thereafter, the PVA film was taken out, dried with hot air at 40 ° C., and further subjected to heat treatment at 100 ° C. for 5 minutes. The obtained polarizing film had an average thickness of 13 μm, and the polarizing performance was a transmittance of 43.0%, a polarization degree of 99.5%, and a dichroic ratio of 40.1.

(B) Production of Polarizing Plate Next, according to the following Steps 1 to 5, the polarizing film and the polarizing plate protective film were bonded together to produce a polarizing plate.

  Step 1: The optical compensation film and the optical films 1 to 19 with an antireflection layer were immersed in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried. A surface of the optical films 1 to 19 with the antireflection layer provided with the antireflection layer was previously protected with a peelable protective film (PET).

  Similarly, the optical compensation film was immersed in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried.

  Process 2: The above-mentioned polarizing film was immersed for 1 to 2 seconds in the polyvinyl alcohol adhesive tank of 2 mass% of solid content.

  Step 3: Excess adhesive adhered to the polarizing film in Step 2 was lightly removed, and it was sandwiched between the optical compensation film alkali-treated in Step 1 and the optical films with antireflection layers 1 to 19 and laminated.

Process 4: It bonded together at the speed | rate of about 2 m / min with the pressure of 20-30 N / cm < ² > with the two rotating rollers. At this time, care was taken to prevent bubbles from entering.

  Step 5: The sample prepared in Step 4 in a dryer at 80 ° C. was dried for 2 minutes to prepare Polarizing Plates 1-19.

  A polarizing plate on the outermost surface of a liquid crystal display panel (VA type) using a commercially available direct type backlight was carefully peeled off, and polarizing plates 1 to 19 having the same polarization direction were attached thereto.

  The liquid crystal display panels 1 to 19 obtained as described above were placed on a desk 80 cm high from the floor, and a daylight direct fluorescent lamp (FLR40S • D / M-) was placed on the ceiling 3 m high from the floor. X: Matsushita Electric Industrial Co., Ltd.) 40W × 2 were used as one set, and 10 sets were arranged at 1.5 m intervals. At this time, when the evaluator is in front of the display surface of the liquid crystal display panel, the fluorescent lamp is arranged so that the fluorescent lamp comes to the ceiling from the evaluator's overhead to the rear. The liquid crystal display panel was tilted by 25 ° from the vertical direction with respect to the desk, and a fluorescent lamp was reflected so that the visibility of the screen (visibility) was evaluated as follows.

A: You don't have to worry about the movement of the nearest fluorescent light, and you can clearly read characters with a font size of 8 or less. B: The reflection of the nearby fluorescent light is a little worrisome, but you don't care about the distance. Can manage to read characters with a font size of 8 or less C: It is difficult to read characters with a font size of 8 or less. Worrying, the portion of the reflection cannot read characters with a font size of 8 or less. As a result of evaluation, the polarizing plate and liquid crystal display panel of the present invention using the antireflection films 6 to 19 of the present invention Is also an evaluation result of B or more, and the visibility was better than the comparative sample in which the evaluation result was C or less. Moreover, although it was a liquid crystal display panel having a large influence of heat due to the use of a direct type backlight, the liquid crystal display panel using the antireflection film of the present invention showed no deterioration in visibility over a long period of time.

  Further, the anti-fouling film of the present invention is evaluated by changing the magic resistance recovery test condition of 40 ° C. for 3 days to 1 week of liquid crystal display panel lighting (15 to 25 ° C. room temperature) to evaluate the antifouling property on the surface of the liquid crystal display panel. It was confirmed that the liquid crystal display panel of the present invention using 6 to 19 was good in recovering the magic wiping property.

Example 4
A 1.1 mm thick soda lime glass obtained from Nippon Sheet Glass Co., Ltd. was blasted with a monodispersed alumina crystal “Sumicorundum AA-5” (average particle size 5 μm) obtained from Sumitomo Chemical Co., Ltd. The blast pressure was 0.5 kg / cm ² (50 kPa), and the blast time was 120 seconds. The glass thus blasted is ultrasonically cleaned and dried, then immersed in 10% by weight hydrofluoric acid at 40 ° C. for 1,200 seconds, then thoroughly washed with pure water and dried to obtain a mold glass. Produced.

10 g of urethane acrylate UV curable resin “UA-1” obtained from Shin-Nakamura Chemical Co., Ltd. and 10 μg of ethyl acetate, and photopolymerization initiator “Lucirin TPO” obtained from BASF (chemical name: 2, 0.5 g of 4,6-trimethylbenzoyldiphenylphosphine oxide) was dissolved to prepare a coating solution. This coating solution was coated on one side of the cellulose ester film 1 used in Example 1 in the dark using a # 16 bar coater. After drying this in an oven at 80 ° C. for 5 minutes, the uncured coated surface is brought into close contact with the roughened surface of the mold glass prepared above using a hand roller so that no bubbles enter. The ultraviolet curable resin was cured by irradiating ultraviolet rays with a light amount of 450 mJ / cm ² from the cellulose ester film 1 side using a high pressure mercury lamp.

  The cellulose ester film 1 coated with the ultraviolet curable resin was peeled from the glass mold to obtain a film having fine irregularities formed on the surface. When the surface shape of the obtained antiglare hard coat film was measured by a non-contact three-dimensional surface shape / roughness measuring instrument “New View 5010” manufactured by Zygo Corporation, the surface has an inclination angle of 1 ° or less. The ratio of the surface was 19%, the ratio of the surface having an inclination angle of 5 ° or more was 8%, and the standard deviation of the height was 0.17 μm.

  A high refractive index layer and a low refractive index layer were provided on the produced antiglare hard coat film in the same manner as in Example 1.

  When the same evaluation as Example 1 was performed about the obtained anti-glare antireflection film, the antireflection film having the constitution of the present invention was excellent in antifouling property and achieved both low refractive index and high pencil hardness. It has been found that a dazzling antireflection film can be obtained.

Claims (12)

In an antireflection film in which a hard coat layer is provided on a transparent support, and a low refractive index layer is provided directly or via a high refractive index layer on the hard coat layer,
The low refractive index layer is a film mainly composed of a silicon dioxide polymer containing silica fine particles having voids, has the following magic resistance, and the antireflection film is placed at 40 ° C. for 3 days. An anti-reflective film characterized in that when it is peeled off, the number of times that the portion that has become magic-resistant and cannot be wiped off again can be wiped up multiple times.
Magic resistance: Write a line with black oil-based magic (ZEBRA's Mackey extra fine) on the antireflection film, and wipe the line with Bencotton (Asahi Kasei) while pressing with a pressure of 1.0 kg / cm ² , If it is possible to wipe it off within 5 round trips), if it can be wiped off, write the line again with the magic at the place where the magic line was written, and check whether it can be wiped off. This operation is repeated, and the number of times that it can be written and wiped with a magic pen is taken as the value of magic resistance. 2. The antireflection film according to claim 1, wherein the low refractive index layer contains a silicone nonionic surfactant having a viscosity of 1 to 500 CS at 25 ° C. 3. The antireflection film according to claim 2, wherein a terminal of the silicone-based nonionic surfactant has a polar group. The antireflection film according to any one of claims 1 to 3, wherein the silica fine particles having voids are hollow silica fine particles. The antireflection according to any one of claims 1 to 4, wherein the silicon dioxide polymer of the low refractive index layer is a hydrolyzate of an alkoxysilicon compound and a condensate formed by a subsequent condensation reaction. the film. The antireflection film according to claim 1, wherein the transparent support is a cellulose ester film having a thickness of 20 to 60 μm. In an antireflection film in which a hard coat layer is provided on a transparent support, and a low refractive index layer is provided directly or via a high refractive index layer on the hard coat layer,
The low refractive index layer is a film mainly composed of silicon dioxide polymer containing silica fine particles having voids, and contains a silicone-based nonionic surfactant having a viscosity of 1 to 500 CS at 25 ° C. An antireflection film. The antireflection film according to any one of claims 1 to 7, wherein a hard coat layer, a high refractive index layer or a low refractive index layer is applied, and then dried at a temperature of 60 to 100 ° C. The manufacturing method of a prevention film. A method for producing an antireflection film, comprising subjecting the antireflection film according to any one of claims 1 to 7 to a heat aging treatment at 45 ° C or more for 24 hours or more. A polarizing plate comprising the antireflection film according to claim 1 on at least one surface. A liquid crystal display device using the polarizing plate according to claim 10. The liquid crystal display device according to claim 11, wherein a direct type backlight is used.