JP2005037927A - Optical laminated film - Google Patents

Abstract

An object of the present invention is to provide an optical laminate that has lower reflectivity, less glare and reflection than conventional ones, excellent visibility, and excellent contrast in bright and dark displays when used in a liquid crystal display device. To provide a film.
An optical laminated film in which at least a hard coat layer and a low refractive index layer are laminated in this order on the surface of a base film made of a transparent resin, and the refractive index of the low refractive index layer is 1.35. An optical laminated film having a reflectance of 0.8% or less at a wavelength of 550 nm and a reflectance of 1.2% or less at a wavelength of 430 to 700 nm.

Description

  The present invention relates to an optical laminated film, and more particularly to an optical laminated film obtained by laminating a single layer film capable of efficiently realizing a low reflectance. Furthermore, it is related with the polarizing plate with an antireflection function using this optical laminated film, and an optical product using the same.

A polarizing film for a liquid crystal display device (hereinafter referred to as “LCD”) may be subjected to processing for providing an antireflection layer in order to prevent reflection. In particular, polarizing films in LCDs used outdoors and the like are required to have a high-performance antireflection function. Therefore, an antireflection film is formed as a multilayer film or a single layer film on the surface of the base film.
As a method of coating the surface of the base film with the antireflection film of the multilayer film, a method of laminating a film having a relatively high refractive index and a film having a relatively low refractive index on the transparent base film in this order. Alternatively, there is a method of obtaining a multilayer film by laminating a large number of films having relatively high refractive index and low refractive index by the laminating method (see, for example, Patent Document 1).
As a method for coating the surface of the base film, a sol-gel method, a vacuum deposition method, a sputtering method, a chemical vapor deposition (CVD) method, or the like is widely used.
Further, as a method for reducing the reflectance of the substrate film surface by coating the substrate film surface with a single-layer antireflection film, a film having a refractive index lower than the refractive index of the substrate is provided on the substrate film surface. How to create is known.
Among them, a multi-component metal oxide film is formed on glass by a sol-gel method, then the multi-component metal oxide film is phase-separated by heat treatment, and then the phase-separated metal oxide film is fluorinated. There has been proposed a method of making a porous structure by using a difference in the etching rate of each phase by etching with hydrogen acid (see, for example, Non-Patent Document 1).

  As another method, a composite film of magnesium oxide and carbon dioxide is formed on glass by a sol-gel method, and then exposed to a fluorine-containing gas at a high temperature to replace oxygen with fluorine. A method for reducing the rate has been proposed (see, for example, Non-Patent Document 2).

Examples of the method for forming a film include a sol-gel method, a vacuum deposition method, a sputtering method, and a chemical vapor deposition method, all of which include a step involving high temperature and vacuum, and in particular, a step of raising the substrate temperature. In some cases, the resin base material may be deformed or deteriorated in a high-temperature process, and it is difficult to change the optical characteristics of the film and form a desired antireflection film. Further, in the vacuum film formation process, gas is released from the resin in the vacuum apparatus, so that a high vacuum necessary for film formation cannot be obtained, and it is difficult to form an antireflection film having desired characteristics. .
Furthermore, when the anti-reflection film is composed of two or more multilayer films, it is difficult to reduce the manufacturing cost because the number of coating times of the film is two times or more, and there is a problem in controlling the film thickness of the multilayer film. was there.

On the other hand, when the antireflection film is composed of a single layer, the reflectance has a smaller incident angle dependency than the multilayer film, and the wavelength dependency is small. And it has the advantage that it is easy to promote the cost reduction of manufacture.
However, the above prior art includes a high-temperature process in the manufacturing process, and thus is not suitable as a method for forming an antireflection film on a resin substrate. Furthermore, in these methods, it is necessary to perform a heat treatment and an etching process after forming a metal oxide film once, or to perform a chemical reaction process with a gas after forming a metal oxide film once. It is difficult to reduce costs.

Therefore, in Patent Document 2, a coating liquid containing at least one organic silicon compound containing an organosilicon compound having an amino group or a hydrolyzate thereof is applied to the surface of a resin substrate, and the coating liquid is dried. Forming a primary coating on the surface of the resin base material, and forming a silicon dioxide film having a refractive index of 1.40 or less and an uneven surface on the primary coating. A method for producing a featured low reflection resin substrate is described. According to the publication, it is described that it can be simultaneously formed on the entire surface of a resin base material with good adhesion by a low temperature process.
However, when the low-reflection resin substrate described in the publication is used particularly for a liquid crystal display device, visibility (for example, luminance) may be deteriorated, and contrast of bright and dark display may be deteriorated. Therefore, further improvement is required.

JP-A-4-357134 JP 2002-328202 A S. P. Mukherjee et al. Non-Cryst. Solids, Vol. 48, p177 (1982) J. et al. H. Simons et al. Non-Cryst. Solids, Vol. 178, p166 (1994)

  Therefore, the object of the present invention is that the reflectance is lower than that of the conventional one, the glare and the reflection are less, the scratch resistance and the visibility are excellent, and further, when used in a liquid crystal display device, the contrast in bright and dark display is improved. The object is to provide an excellent optical laminated film.

  As a result of intensive studies to achieve the above object, the present inventors achieved the above object by laminating only one layer having a lower refractive index than the conventional one on a base film laminated with a hard coat layer. As a result, the present inventors have completed further research based on this finding and have completed the present invention.

Thus, according to the present invention,
(1) An optical laminated film obtained by laminating at least a hard coat layer and a low refractive index layer in this order on the surface of a base film comprising a transparent resin, and the refractive index of the low refractive index layer is 1. 35 or less, an optical laminated film having a reflectance at a wavelength of 550 nm of 0.8% or less and a reflectance at a wavelength of 430 to 700 nm of 1.2% or less,
(2) The optical laminated film according to the above (1), wherein the depth or height of the die line of the base film made of the transparent resin is 0.1 μm or less,
(3) The optical laminated film according to (1) or (2), wherein the low refractive index layer is a layer made of airgel,
(4) The optical laminate according to any one of (1) to (3), wherein the transparent resin is a resin selected from the group consisting of a polymer resin having an alicyclic structure, a cellulose resin, and a polyester resin. the film,
(5) The optical laminated film according to any one of (1) to (4), which is an antireflection protective film for an optical member,
(6) The optical laminated film according to (5), which is a polarizing plate protective film,
(7) A reflection preventing film characterized in that a polarizing film is laminated on the surface opposite to the surface on which the low refractive index layer of the base material film of the polarizing plate protective film according to (6) is provided. Functional polarizing plate,
And (8) Optical products each comprising the polarizing plate with antireflection function described in (7) are provided.

  According to the present invention, there is provided an optical laminated film having low reflectance, less glare and reflection, excellent scratch resistance and visibility, and excellent contrast in bright and dark display when used in a liquid crystal display device. Can do.

  The optical laminated film of the present invention is obtained by laminating at least a hard coat layer and a low refractive index layer in this order on the surface of a base film comprising a transparent resin.

  The transparent resin used for the base film of the optical laminated film of the present invention is not particularly limited as long as it has a thickness of 1 mm and a total light transmittance of 80% or more. For example, it has an alicyclic structure. Polymer resin, chain olefin polymer such as polyethylene and polypropylene, polycarbonate polymer, polyester polymer, polysulfone polymer, polyethersulfone polymer, polystyrene polymer, polyolefin polymer, polyvinyl alcohol Examples of the polymer include cellulose polymers, cellulose acetate polymers, polyvinyl chloride polymers, polymethacrylate polymers, and triacetyl cellulose. These polymers can be used alone or in combination of two or more. Among these, cellulose resins such as diacetyl cellulose, propionyl cellulose, triacetyl cellulose, and butyryl cellulose; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; A polymer resin having an alicyclic structure is preferable, and from the viewpoints of transparency and lightness, triacetyl cellulose, polyethylene terephthalate, and a polymer resin having an alicyclic structure are preferable, and from the viewpoint of dimensional stability and film thickness controllability. To polyethylene terephthalate and a polymer resin having an alicyclic structure are more preferable.

  The polymer resin having an alicyclic structure has an alicyclic structure in the main chain and / or side chain, and contains an alicyclic structure in the main chain from the viewpoint of mechanical strength, heat resistance, etc. Is preferred.

  Examples of the alicyclic structure of the polymer include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene) structure. From the viewpoint of mechanical strength and heat resistance, cycloalkane. A structure or a cycloalkene structure is preferable, and a cycloalkane structure is most preferable. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 in the mechanical strength, The properties of heat resistance and film formability are highly balanced and suitable. The proportion of the repeating unit containing the alicyclic structure in the alicyclic structure-containing polymer used in the present invention may be appropriately selected according to the purpose of use, but is preferably 30% by weight or more, Preferably it is 50% by weight or more, particularly preferably 70% by weight or more, and most preferably 90% by weight or more. When the ratio of the repeating unit having an alicyclic structure in the polymer having an alicyclic structure is within this range, it is preferable from the viewpoint of the transparency and heat resistance of the base film.

Specifically, the polymer resin having an alicyclic structure includes (1) a norbornene polymer, (2) a monocyclic olefin polymer, (3) a cyclic conjugated diene polymer, and (4) vinyl. Examples thereof include alicyclic hydrocarbon polymers and hydrogenated products thereof. Among these, norbornene-based polymers are more preferable from the viewpoints of transparency and moldability.
Specific examples of the norbornene-based polymer include ring-opening polymers of norbornene-based monomers, ring-opening copolymers of norbornene-based monomers and other monomers capable of ring-opening copolymerization, and hydrogenated products thereof, norbornene-based polymers Examples include addition polymers of monomers and addition copolymers with other monomers copolymerizable with norbornene monomers. Among these, from the viewpoint of transparency, a ring-opening (co) polymer hydrogenated product of a norbornene-based monomer is most preferable.
The polymer resin having the alicyclic structure is selected from known polymers disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-321302.

  The glass transition temperature of the transparent resin used for this invention becomes like this. Preferably it is 80 degreeC or more, More preferably, it is 100-250 degreeC. A base film comprising a transparent resin having a glass transition temperature in such a range is excellent in durability without causing deformation or stress during use at high temperatures.

  The molecular weight of the transparent resin used in the present invention is polyisoprene measured by gel permeation chromatography (hereinafter abbreviated as “GPC”) using cyclohexane (toluene when the polymer resin is not dissolved) as a solvent. Or it is the weight average molecular weight (Mw) of polystyrene conversion, and is 10,000-100,000 normally, Preferably it is 25,000-80,000, More preferably, it is 25,000-50,000. When the weight average molecular weight is in such a range, the mechanical strength and moldability of the film are highly balanced and suitable.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the transparent resin used in the present invention is not particularly limited, but is usually 1.0 to 10.0, preferably 1.0 to 4.0. Preferably it is the range of 1.2-3.5.

  The base film comprising the transparent resin used for the optical laminated film of the present invention is composed of only the transparent resin, but may contain other compounding agents. The compounding agent is not particularly limited, but inorganic fine particles; antioxidants, heat stabilizers, light stabilizers, weathering stabilizers, UV absorbers, near infrared absorbers and other stabilizers; resins such as lubricants and plasticizers Modifiers; coloring agents such as dyes and pigments; antistatic agents and the like. These compounding agents can be used singly or in combination of two or more, and the compounding amount is appropriately selected within a range not impairing the object of the present invention, and usually 0 to 100 parts by weight of the transparent resin. 5 parts by weight, preferably 0 to 3 parts by weight.

The film thickness of the base film is preferably 30 to 300 μm, more preferably 40 to 200 μm from the viewpoint of mechanical strength and the like.
Moreover, it is preferable that the film thickness variation of the base film is within 3% of the film thickness over the entire width of the base film. When the film thickness fluctuation | variation of a base film exists in the said range, the adhesiveness of a hard-coat layer and the surface smoothness of the low-refractive-index layer laminated | stacked on it can be improved.

In the present invention, the depth or height of the die line of the substrate film is preferably 0.1 μm or less, more preferably 0.05 μm or less, and particularly preferably 0.03 μm or less. By setting the depth or height of the die line of the base film in the above range, when the optical laminated film of the present invention is used as a polarizing plate protective film, the die line is not noticeable and excellent in visibility.
The die line can be measured using a non-contact type three-dimensional surface shape / roughness measuring machine.

In this invention, it is preferable that content of the volatile component of a base film is 0.1 weight% or less, and it is further more preferable that it is 0.05 weight% or less. When the content of the volatile component is within the above range, the dimensional stability of the base film is improved, and the lamination unevenness when the hard coat layer is laminated can be reduced. In addition, since a uniform low refractive index layer can be formed over the entire surface of the film, a uniform antireflection effect can be obtained over the entire surface of the film.
The volatile component is a substance having a molecular weight of 200 or less contained in a trace amount in the base film, and examples thereof include a residual monomer and a solvent. The content of the volatile component can be quantified by analyzing the base film by gas chromatography as the sum of substances having a molecular weight of 200 or less contained in the transparent resin.

In the present invention, the saturated water absorption of the substrate film is preferably 0.01% by weight or less, more preferably 0.007% by weight or less. When the saturated water absorption exceeds 0.01% by weight, the adhesiveness between the hard coat layer and the base film and the adhesiveness between the hard coat layer and the low refractive index layer are lowered, and the low refractive index is low for long-term use. Peeling of layers tends to occur, which is not preferable.
The saturated water absorption of the base film can be determined by immersing at 23 ° C. for 1 week and measuring the increased weight according to ASTM D530.

As the substrate film used in the present invention, one having one or both surfaces subjected to surface modification treatment may be used. By performing the surface modification treatment, the adhesion with the hard coat layer can be improved. Examples of the surface modification treatment include energy beam irradiation treatment and chemical treatment.
Examples of the energy ray irradiation treatment include corona discharge treatment, plasma treatment, electron beam irradiation treatment, ultraviolet ray irradiation treatment, and the like. From the viewpoint of treatment efficiency, corona discharge treatment and plasma treatment are preferred, and corona discharge treatment is particularly preferred.
As the chemical treatment, it may be immersed in an aqueous oxidizing agent solution such as potassium dichromate solution or concentrated sulfuric acid and then thoroughly washed with water. It is effective to shake in the immersed state, but there is a problem that the surface will dissolve or the transparency will be lowered if treated for a long time. Depending on the reactivity and concentration of the chemical used, the treatment time etc. It needs to be adjusted.

Examples of the method for forming the base film used for the optical laminated film of the present invention include a solution casting method and a melt extrusion molding method. Among these, the melt extrusion molding method is preferable because the content of volatile components in the base film and the thickness unevenness can be reduced. Furthermore, examples of the melt extrusion method include a method using a die and an inflation method, but a method using a T die is preferable in terms of excellent productivity and thickness accuracy.
When adopting a method using a T die as a method for forming a base film, the melting temperature of the transparent resin in the extruder having the T die should be 80 to 180 ° C. higher than the glass transition temperature of the transparent resin. The temperature is preferably 100 to 150 ° C. higher than the glass transition temperature. If the melting temperature in the extruder is excessively low, the fluidity of the transparent resin may be insufficient. Conversely, if the melting temperature is excessively high, the resin may be deteriorated.

In addition, as means for reducing the depth or height of the die line of the base film used in the present invention to 0.1 μm or less, (1) the tip of the die lip is plated with chromium, nickel, titanium or the like. (2) Use a die in which a film such as TiN, TiAlN, TiC, CrN, or DLC (diamond-like carbon) is formed on the inner surface of the die lip by the PVD (Physical Vapor Deposition) method or the like; (3) And (4) a method of using a die obtained by nitriding the surface of the tip of the die lip.
Such a die has high surface hardness and low friction with the resin, so that it is possible to prevent burnt dust and the like from being mixed into the obtained base film, and to make the die line 0.1 μm or less. Can do.
Further, by using a die with good surface accuracy, it is possible to reduce the thickness unevenness. The surface roughness regarding the microscopic irregularities on the surface can be expressed by “average height Ra”, and the average height Ra of the die inner surface, particularly the tip of the die lip is preferably 0.2 μm or less, more preferably Ra is 0. .1 μm or less.
The average height Ra is the same as the “arithmetic average height Ra” defined by JIS B 0601-2001. Specifically, the measurement curve has a cutoff value of 0.8 mm and a phase compensated high frequency range. Obtain a roughness curve through a filter, extract a certain reference length from the roughness curve in the direction of the average line, and sum and average the absolute values of the deviations from the average line of the extracted part to the roughness curve. It is calculated by.

  Other means for reducing the depth or height of the die line of the base film to 0.1 μm or less are to remove the material adhering to the die lip (for example, burns and dust), and to improve the releasability of the die lip. Examples thereof include making the wettability of the die lip uniform over the entire surface, reducing the resin powder, reducing the amount of dissolved oxygen in the resin pellets, and installing a polymer filter in the melt extruder.

  Moreover, as means for reducing the content of volatile components in the base film used in the optical laminated film of the present invention, (1) reducing the amount of volatile components in the transparent resin itself; (2) melt extrusion Examples thereof include a method of forming a base film by a forming method; (3) pre-drying a transparent resin used before forming the film; The preliminary drying is performed with a hot air dryer or the like, for example, in the form of pellets or the like. The drying temperature is preferably 100 ° C. or more, and the drying time is preferably 2 hours or more. By performing preliminary drying, the amount of volatile components in the base film can be reduced, and foaming of the transparent resin to be extruded can be prevented.

The material constituting the hard coat layer used in the optical laminated film of the present invention can exhibit a hardness of 2H or higher in a pencil hardness test (test plate is a glass plate) shown in JIS K5600-5-4. If it is, it will not be restrict | limited in particular.
Examples thereof include organic hard coat materials such as organic silicone, melamine, epoxy, acrylic, and urethane acrylate; inorganic hard coat materials such as silicon dioxide; and the like. Of these, urethane acrylate-based and polyfunctional acrylate-based hard coat materials are preferably used from the viewpoint of good adhesive strength and excellent productivity.
In the present invention, the refractive index of the hard coat layer to be used is preferably 1.5 or more, more preferably 1.53 or more, and particularly preferably 1.55 or more. An optical laminated film having excellent antireflection performance in a wide band, easy design of a low refractive index layer laminated on the hard coat layer, and excellent scratch resistance, because the refractive index of the hard coat layer is in the above range. Obtainable.
For the purpose of improving the refractive index of the hard coat layer, improving the flexural modulus, stabilizing the volume shrinkage, heat resistance, antistatic properties, antiglare properties, etc. Various fillers such as silica, alumina, and hydrated alumina may be added. Furthermore, various additives such as an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a leveling agent, and an antifoaming agent can be added.
In the case where the hard coat layer contains a filler, when adjusting the refractive index and antistatic property, it is possible to easily adjust the refractive index and antistatic property of the hard coat layer among various fillers. Titanium, zirconium oxide, zinc oxide, tin oxide, cerium oxide, antimony pentoxide, tin-doped indium oxide (ITO), antimony-doped tin oxide (IZO), aluminum-doped zinc oxide (AZO), fluorine Doped tin oxide (FTO) is preferable, and antimony pentoxide, ITO, IZO, ATO, and FTO are more preferable from the viewpoint that transparency can be maintained. The filler has a primary particle diameter of 1 nm or more and 100 nm or less, preferably 30 nm or less.
In the case of adding a filler to the hard coat layer, when imparting antiglare properties, among various fillers, those having an average particle size of 0.5 to 10 μm are preferable, and those having 1 to 7 μm are more preferable. Specific examples of fillers that impart antiglare properties include polymethyl methacrylate resin, fluorine resin, vinylidene fluoride resin, silicone resin, epoxy resin, nylon resin, polystyrene resin, phenol resin, polyurethane resin, crosslinked acrylic resin, crosslinked polystyrene. Resin fillers of resin, melamine resin, benzoguanamine resin; or inorganic fillers such as titanium oxide, aluminum oxide, indium oxide, zinc oxide, antimony oxide, tin oxide, zirconium oxide, ITO, magnesium fluoride, and silicon oxide.

The method for forming the hard coat layer is not particularly limited. For example, the hard coat layer forming coating solution is applied on a base film by a known coating method and cured by heating or ultraviolet irradiation. A method is mentioned.
The thickness of the hard coat layer is preferably 0.5 to 30 μm, more preferably 3 to 15 μm. If the thickness of the hard coat layer is too thin, it will not be possible to maintain the hardness of each layer formed on it, and conversely, if it is too thick, the flexibility of the entire optical laminated film will decrease, and it will take time to cure and decrease production efficiency May be incurred.

The low refractive index layer used in the optical laminated film of the present invention is not particularly limited as long as it is a material constituting a layer having a refractive index of 1.35 or less, but it is easy to control the refractive index and is water resistant. In terms of superiority, airgel is preferred.
The airgel is a transparent porous body in which minute bubbles are dispersed in a matrix. Most of the size of the bubbles is 200 nm or less, and the content of the bubbles is usually 10% by volume or more and 60% by volume or less, preferably 20% by volume or more and 40% by volume or less.
Specific examples of the airgel in which minute bubbles are dispersed include silica aerogel and a porous body in which hollow particles are dispersed in a matrix.
Silica airgel is a wet state composed of a silica skeleton obtained by hydrolysis polymerization reaction of alkoxysilane as disclosed in US Pat. No. 4,402,927, US Pat. No. 4,432,956, US Pat. No. 4,610,863 and the like. The gel-like compound can be produced by drying in a supercritical state above the critical point of the solvent in the presence of a solvent (dispersion medium) such as alcohol or carbon dioxide. In supercritical drying, for example, a gel compound is immersed in liquefied carbon dioxide, and all or part of the solvent contained in the gel compound is replaced with liquefied carbon dioxide having a critical point lower than that of the solvent. It can be carried out by drying under supercritical conditions of a single system of or a mixed system of carbon dioxide and a solvent. Silica airgel may be produced in the same manner as described above using sodium silicate as a raw material as disclosed in US Pat. No. 5,137,279, US Pat. No. 5,124,364, and the like.

  Here, as disclosed in JP-A-5-279011 and JP-A-7-138375, the gel-like compound obtained by hydrolysis and polymerization reaction of alkoxysilane as described above is hydrophobized. It is preferable to impart hydrophobicity to the silica airgel. Hydrophobic silica airgel imparted with hydrophobicity as described above can prevent moisture, water, and the like from entering, and prevent the performance of the silica airgel from being degraded in refractive index, light transmittance, and the like.

  This hydrophobization treatment step can be performed before or during supercritical drying of the gel compound. The hydrophobization treatment is performed to make the hydrophobization by reacting the hydroxyl group of the silanol group present on the surface of the gel compound with the functional group of the hydrophobization treatment agent and replacing it with the hydrophobic group of the hydrophobization treatment agent. . As a method of performing the hydrophobization treatment, the gel is immersed in a hydrophobization treatment solution in which the hydrophobization treatment agent is dissolved in a solvent, mixed, and so on. There is a method in which the hydrophobization reaction is performed by heating accordingly.

  Examples of the solvent used for the hydrophobic treatment include methanol, ethanol, isopropanol, xylene, toluene, benzene, N, N-dimethylformamide, hexamethyldisiloxane, and the like, but the hydrophobic treatment agent can be easily dissolved. And what is necessary is just to be able to substitute for the solvent which the gel before hydrophobization treatment contains, and it is not limited to these. Further, when supercritical drying is performed in a later step, a medium that can be easily supercritically dried, such as methanol, ethanol, isopropanol, liquefied carbon dioxide, or the like, is preferable. Examples of the hydrophobizing agent include hexamethyldisilazane, hexamethyldisiloxane, trimethylmethoxysilane, dimethyldimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, trimethylethoxysilane, dimethyldiethoxysilane, and methyltriethoxysilane. Etc.

The refractive index of silica airgel can be freely changed by the raw material compounding ratio of silica airgel.
When the low refractive index layer is a silica aerogel, the formation method is not particularly limited. For example, the gel compound is coated on the hard coat layer by a known coating method, and the supercritical drying is performed. The method of forming by performing is mentioned. Further, the hydrophobization treatment may be performed before or during supercritical drying. In the supercritical drying, for example, the gel compound is immersed in liquefied carbon dioxide, and all or a part of the solvent containing the gel compound is replaced with liquefied carbon dioxide having a lower critical point than the solvent. It can be carried out by drying under supercritical conditions of a single system of carbon dioxide or a mixed system of carbon dioxide and a solvent.

As a porous material in which hollow particles are dispersed in a matrix, hollow fine particles having voids inside fine particles as disclosed in JP-A Nos. 2001-233611 and 2003-149642 are used as binder resins. And a porous material dispersed in the substrate.
The binder resin can be selected from resins suitable for conditions such as dispersibility of hollow fine particles, transparency of the porous body, and strength of the porous body. For example, conventionally used polyester resins and acrylic resins Resin, urethane resin, vinyl chloride resin, epoxy resin, melamine resin, fluorine resin, silicon resin, butyral resin, phenol resin, vinyl acetate resin, UV curable resin, electron beam curable resin, emulsion resin, water-soluble resin, hydrophilic resin Further, a mixture of these resins, a coating resin such as a copolymer or a modified product of these resins, a hydrolyzable organosilicon compound such as alkoxysilane, and a hydrolyzate thereof can be used.
Among these, hydrolyzable organosilicon compounds such as acrylic resins, epoxy resins, urethane resins, silicon resins, alkoxysilanes, and hydrolysates thereof are preferable from the viewpoint of the dispersibility of the fine particles and the strength of the porous body.
In the present invention, when a porous body in which hollow particles are dispersed in a matrix is used as the low refractive index layer, the reflection characteristics and antifouling properties of the low refractive index layer are improved. You may mix.
The fluororesin is not limited as long as it is an amorphous fluoropolymer that is substantially free of light scattering by crystals, but tetrafluoroethylene / vinylidene fluoride / hexafluoropropylene = 37-48 wt% / 15- An amorphous fluoroolefin copolymer such as a 35% by weight / 26 to 44% by weight terpolymer and a polymer having a fluorine-containing aliphatic ring structure are preferred because of excellent mechanical properties.

The hydrolyzable organosilicon compound such as alkoxysilane and the hydrolyzate thereof are formed from one or more compounds selected from the group consisting of the following (a) to (c), and in the molecule: -(O-Si) _m -O- (wherein _m represents a natural number) has a bond.
(A) A compound represented by formula (1): SiX ₄ .
(B) At least one partial hydrolysis product of the compound represented by the formula (1).
(C) At least one complete hydrolysis product of the compound represented by the formula (1).

In the compound represented by the formula (1) in (a), X is a halogen atom such as a chlorine atom or a bromine atom; a monovalent hydrocarbon group which may have a substituent; an oxygen atom; Organic acid radicals such as nitrate radicals; β-diketonate groups such as acetylacetonate; inorganic acid radicals such as nitrate radicals and sulfate radicals; alkoxy groups such as methoxy groups, ethoxy groups, n-propoxy groups, and n-butoxy groups; or hydroxyl groups Represents.
Among these, the compound represented by the formula (1) is represented by the formula (2): R _a SiY _4-a [wherein R represents a monovalent hydrocarbon group which may have a substituent. And a represents an integer of 0 to 2, and when a is 2, R may be the same or different. Y represents a hydrolyzable group, and Y may be the same or different. ] The silicon compound represented by this is preferable.

Examples of the monovalent hydrocarbon group which may have a substituent include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group; a cyclopentyl group, A cycloalkyl group such as a cyclohexyl group; an aryl group optionally having a substituent such as a phenyl group, a 4-methylphenyl group, a 1-naphthyl group, and a 2-naphthyl group; an alkenyl group such as a vinyl group and an allyl group; Aralkyl groups such as benzyl group, phenethyl group and 3-phenylpropyl group; haloalkyl groups such as chloromethyl group and γ-chloropropyl group; 3,3,3-trifluoropropyl group, methyl-3,3,3-tri Perfluoroalkyl group such as fluoropropyl group, heptadecafluorodecyl group, trifluoropropyl group, tridecafluorooctyl group; Alkenylcarbonyloxyalkyl groups such as methacryloxypropyl groups; alkyl groups having epoxy groups such as γ-glycidoxypropyl groups and 3,4-epoxycyclohexylethyl groups; alkyl groups having mercapto groups such as γ-mercaptopropyl groups An alkyl group having an amino group such as a 3-aminopropyl group; Among these, an alkyl group having 1 to 4 carbon atoms, a perfluoroalkyl group, and a phenyl group are preferable because of easy synthesis, easy availability, and low reflection characteristics.

In the formula (2), Y represents a hydrolyzable group. Here, the hydrolyzable group refers to a group that is hydrolyzed in the presence of an acid or a base catalyst as desired to form a — (O—Si) _m —O— bond.
Specific examples of the hydrolyzable group include alkoxy groups such as methoxy group, ethoxy group and propoxy group; acyloxy groups such as acetoxy group and propionyloxy group; oxime group (—O—N═C—R ′ (R ″) )), Enoxy group (—O—C (R ′) ═C (R ″) R ′ ″), amino group, aminoxy group (—O—N (R ′) R ″), amide group (— N (R ′) — C (═O) —R ″) and the like. In these groups, R ′, R ″, and R ′ ″ each independently represent a hydrogen atom or a monovalent hydrocarbon group. Among these, Y is preferably an alkoxy group from the viewpoint of availability.

  The silicon compound represented by the formula (2) is preferably a silicon compound in which a is an integer of 0 to 2 in the formula (2). Specific examples thereof include alkoxysilanes, acetoxysilanes, oxime silanes, enoxysilanes, aminosilanes, aminoxysilanes, amidosilanes and the like. Among these, alkoxysilanes are more preferable because of their availability.

  In the formula (2), examples of the tetraalkoxysilane in which a is 0 include tetramethoxysilane and tetraethoxysilane. Examples of the organotrialkoxysilane in which a is 1 include methyltrimethoxysilane and methyltriethoxy. Examples include silane, methyltriisopropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, and the like. Examples of the diorganodialkoxysilane in which a is 2 include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane.

  The molecular weight of the compound represented by the formula (1) is not particularly limited, but is preferably 40 to 300, and more preferably 100 to 200.

  At least one partial hydrolysis product (hereinafter referred to as “compound (3)”) of the compound represented by formula (1) of (b), and represented by formula (1) of (c). At least one complete hydrolysis product of the compound (hereinafter referred to as “compound (4)”) is obtained by fully or partially hydrolyzing one or more of the compounds represented by the formula (1). Can be obtained by condensation.

Compound (3) and compound (4) are, for example, a metal tetraalkoxide represented by Si (Or) ₄ (r represents a monovalent hydrocarbon group) and a molar ratio [H ₂ O] / [Or ] Is 1.0 or more, for example, 1.0 to 5.0, preferably 1.0 to 3.0, and can be obtained by hydrolysis in the presence of water. Hydrolysis can be performed by stirring the whole volume at a temperature of 5 to 100 ° C. for 2 to 100 hours.

When hydrolyzing the compound represented by the formula (1), a catalyst may be used as necessary. The catalyst to be used is not particularly limited, but the obtained partial hydrolyzate and / or hydrolyzate is likely to have a two-dimensional cross-linked structure, and the condensed compound is easily made porous. From the viewpoint of shortening the time required, an acid catalyst is preferred.
The acid catalyst to be used is not particularly limited. For example, acetic acid, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid, malonic acid, toluenesulfonic acid, Organic acids such as acids; inorganic acids such as hydrochloric acid, nitric acid, and halogenated silane; acidic sol-like fillers such as acidic colloidal silica and oxidized titania sol; These acid catalysts can be used alone or in combination of two or more.
Instead of the acid catalyst, a base catalyst such as an aqueous solution of an alkali metal or alkaline earth metal hydroxide such as sodium hydroxide or calcium hydroxide, an aqueous ammonia or an aqueous solution of amines may be used.

  The molecular weights of the compound (3) and the compound (4) are not particularly limited, but usually the weight average molecular weight is in the range of 200 to 5,000.

The hollow fine particles are not particularly limited as long as they are fine particles of an inorganic compound, but inorganic hollow fine particles in which cavities are formed inside the outer shell are preferable, and use of silica-based hollow fine particles is particularly preferable.
As the inorganic compound, an inorganic oxide is common. As the inorganic _{oxide, SiO 2, Al 2 O 3} , B 2 O 3, TiO 2, ZrO 2, SnO 2, Ce 2 O 3, P 2 O 5, Sb 2 O 3, MoO 3, ZnO 2, WO One or two or more of ₃ or the like can be mentioned. Examples of the two or more inorganic oxides include TiO ₂ —Al ₂ O ₃ , TiO ₂ —ZrO ₂ , In ₂ O ₃ —SnO ₂ , and Sb ₂ O ₃ —SnO ₂ . These can be used alone or in combination of two or more.

  As the inorganic hollow fine particles, (A) an inorganic oxide single layer, (B) a single layer of a composite oxide composed of different kinds of inorganic oxides, and (C) a double layer of (A) and (B) above What is included can be used.

  The outer shell may be porous with pores, or the pores may be closed and the cavity sealed with respect to the outside of the outer shell. The outer shell is preferably a plurality of inorganic oxide coating layers comprising an inner first inorganic oxide coating layer and an outer second inorganic oxide coating layer. By providing the second inorganic oxide coating layer on the outer side, the fine pores of the outer shell are closed to make the outer shell dense, and furthermore, the inorganic hollow fine particles in which the inner cavity is sealed can be obtained. In particular, when a fluorine-containing organosilicon compound is used for forming the second inorganic oxide coating layer, the coating layer containing fluorine atoms is formed, so that the resulting particles have a lower refractive index and are reduced to an organic solvent. The dispersibility is good, and it is also effective for imparting antifouling properties to the low refractive index layer, which is preferable. Such fluorine-containing organic silicon compounds include 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, heptadecafluorodecylmethyldimethoxysilane, heptadecafluorodecyl. Examples thereof include trichlorosilane, heptadecafluorodecyltrimethoxysilane, trifluoropropyltrimethoxysilane, and tridecafluorooctyltrimethoxysilane.

  The thickness of the outer shell is preferably in the range of 1 to 50 nm, particularly 5 to 20 nm. If the thickness of the outer shell is less than 1 nm, the inorganic hollow fine particles may not maintain a predetermined particle shape. On the other hand, when the thickness of the outer shell exceeds 50 nm, the cavities in the inorganic hollow fine particles are small, and as a result, the ratio of the cavities may be reduced and the refractive index may not be sufficiently lowered. Furthermore, the thickness of the outer shell is preferably in the range of 1/50 to 1/5 of the average particle diameter of the inorganic hollow fine particles.

When the first inorganic oxide coating layer and the second inorganic oxide coating layer are provided as outer shells as described above, the total thickness of these layers may be in the range of 1 to 50 nm. For the densified outer shell, the thickness of the second inorganic oxide coating layer is preferably in the range of 20 to 40 nm.
The cavity may contain the solvent used when preparing the inorganic hollow fine particles and / or a gas that enters during drying, and a precursor material for forming the cavity described later remains in the cavity. Also good.
The precursor material is a porous material that remains after removing some of the constituent components of the core particles from the core particles surrounded by the outer shell. As the core particles, porous composite oxide particles made of different types of inorganic oxides are used. The precursor material may remain slightly attached to the outer shell or may occupy most of the interior of the cavity.
The solvent or gas may be present in the pores of the porous material. When the removal amount of the constituent components of the core particles at this time increases, the volume of the cavity increases, and inorganic hollow fine particles having a low refractive index are obtained. The transparent coating obtained by blending these inorganic hollow fine particles reflects with a low refractive index. Excellent prevention performance.

  The average particle size of the inorganic hollow fine particles is not particularly limited, but is preferably 5 to 2000 nm, and more preferably 20 to 100 nm. If it is smaller than 5 nm, the effect of lowering the refractive index due to hollowness is small. Conversely, if it is larger than 2000 nm, the transparency is extremely deteriorated, and the contribution due to diffuse reflection increases. Here, the average particle diameter is a number average particle diameter by observation with a transmission electron microscope.

  The method for producing inorganic hollow fine particles as described above is described in detail, for example, in JP-A-2001-233611, and the inorganic hollow fine particles that can be used in the present invention are produced based on the method described therein. In addition, commercially available inorganic hollow fine particles can also be used.

  The blending amount of the inorganic fine particles is not particularly limited, but is preferably 10 to 30% by weight with respect to the entire low refractive index layer. When the blending amount of the inorganic fine particles is within this range, an optical laminated film having both low refractive index properties and scratch resistance can be obtained.

  The inorganic fine particles can also be used in the form of a dispersion. The type of the organic solvent used in the dispersion is not particularly limited. For example, lower aliphatic alcohols such as methanol, ethanol, isopropanol (IPA), n-butanol, isobutanol; ethylene glycol, ethylene glycol mono Ethylene glycol derivatives such as butyl ether and ethylene glycol monoethyl ether; diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether; diacetone alcohol; aromatic hydrocarbons such as toluene and xylene; aliphatic carbonization such as n-hexane and n-heptane Hydrogen; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; These organic solvents can be used alone or in combination of two or more.

  The formation method is not particularly limited when the low refractive index layer is a porous body in which hollow particles are dispersed in a matrix. For example, hollow fine particles having voids at least inside the fine particles on a hard coat layer are bound as binders. Examples thereof include a method in which a coating solution containing a resin is applied by a known coating method and, if necessary, drying / heating treatment is performed. The temperature of the heating performed as necessary is usually 50 to 200 ° C, preferably 80 to 150 ° C.

In the present invention, the refractive index of the low refractive index layer is 1.35 or less, preferably 1.34 to 1.25, and more preferably 1.34 to 1.30. By setting the refractive index of the low refractive index layer within the above range, an optical laminated film having an excellent balance between antireflection performance and scratch resistance can be obtained.
In the present invention, the thickness of the low refractive index layer is 10 to 1000 nm, preferably 30 to 500 nm.

  An example of the layer structure of the optical laminated film of the present invention is shown in FIG. An optical laminated film 50 shown in FIG. 1 includes a base film layer 11, a hard coat layer 21, and a low refractive index layer 31 from the lower side in the figure.

  In the optical laminated film of the present invention, other layers can be interposed between the base film and the hard coat layer. Examples of other layers include primer layers (not shown).

The primer layer is formed for the purpose of imparting and improving the adhesion between the base film and the hard coat layer. Materials constituting the primer layer include polyester urethane resins, polyether urethane resins, polyisocyanate resins, polyolefin resins, resins having a hydrocarbon skeleton and / or a polybutadiene skeleton in the main chain, polyamide resins, and acrylic resins. , Polyester resin, vinyl chloride-vinyl acetate copolymer, chlorinated rubber, cyclized rubber, or modified products in which polar groups are introduced into these polymers.
Among these, a modified product of a resin having a hydrocarbon skeleton and / or a polybutadiene skeleton in the main chain and a modified product of a cyclized rubber are preferable.

  As the resin having a hydrocarbon skeleton and / or a polybutadiene skeleton in the main chain, a resin having a polybutadiene skeleton or a skeleton obtained by hydrogenation of at least a part thereof, specifically, a polybutadiene resin, a hydrogenated polybutadiene resin, a styrene-butadiene, Examples thereof include a styrene block copolymer (SBS copolymer) and a hydrogenated product thereof (SEBS copolymer). Among these, a modified product of a hydrogenated product of styrene / butadiene / styrene block copolymer is preferable.

  The polar group to be introduced is preferably a carboxylic acid or a derivative thereof, specifically, an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid or fumaric acid; maleyl chloride, maleimide, maleic anhydride, citraconic anhydride Derivatives such as unsaturated carboxylic acid halides, amides, imides, anhydrides, esters, etc .; and the like, and because of excellent adhesion, modification with unsaturated carboxylic acid or unsaturated carboxylic acid anhydride Products are preferred, acrylic acid, methacrylic acid, maleic acid and maleic anhydride are more preferred, and maleic acid and maleic anhydride are particularly preferred. These unsaturated carboxylic acids and the like may be modified by mixing two or more kinds.

The method for forming the primer layer is not particularly limited, and examples thereof include a method in which a primer layer forming coating solution is applied on a substrate film by a known coating method.
The thickness of the primer layer is not particularly limited, but is usually 0.01 to 5 μm, preferably 0.1 to 2 μm.

The optical laminated film of the present invention may further have an antifouling layer (not shown) on the low refractive index layer in order to protect the low refractive index layer and improve the antifouling performance.
The material constituting the antifouling layer is not particularly limited as long as the function of the low refractive index layer is not hindered and the required performance as the antifouling layer is satisfied. Usually, a compound having a hydrophobic group can be preferably used. As specific examples, a perfluoroalkylsilane compound, a perfluoropolyethersilane compound, or a fluorine-containing silicone compound can be used. As a method for forming the antifouling layer, for example, a physical vapor deposition method such as vapor deposition or sputtering, a chemical vapor deposition method such as CVD, a wet coating method, or the like can be used. The thickness of the antifouling layer is not particularly limited, but is usually preferably 20 nm or less, and more preferably 1 to 10 nm.

  The optical laminated film of the present invention has a reflectance of 0.8% or less at a wavelength of 550 nm and a reflectance of 1.2% or less at a wavelength of 430 to 700 nm, preferably a reflectance of 0.7% at a wavelength of 550 nm. The reflectance at a wavelength of 430 to 700 nm is 1.1% or less, and more preferably, the reflectance at a wavelength of 550 nm is 0.7% or less and the reflectance at a wavelength of 430 to 700 nm is 1.0% or less. is there. When the reflectance is in the above range, there is no glare on the surface due to the reflected light, and thus the display content is excellent in visibility. Furthermore, since the reflectance is small over a wide band, the color tone of the display content can be accurately reproduced without coloring the reflected light. Here, the reflectance in the wavelength of 430-700 nm makes the maximum value the reflectance in wavelength 430-700 nm among the reflectance in wavelength 430-700 nm.

Since the optical laminated film of the present invention is excellent in optical properties and has a low reflectance, it is preferably used as an antireflection protective film for optical members.
Anti-reflection protective films generally reduce contrast and image reflection due to reflection of external light in image display devices such as liquid crystal display devices, plasma display panels, EL elements, cathode ray tube display devices, and optical devices such as touch panels. Used to prevent. These antireflection protective films are often provided as an antireflection protective film for optical members usually formed in the uppermost layer on the viewing side in each optical device.

  The optical laminated film of the present invention is preferably applied as a protective film for a polarizing plate in a liquid crystal display device as the optical member.

  The polarizing plate with an antireflection function of the present invention is formed by laminating a polarizing film on the surface opposite to the surface on which the low refractive index layer of the base film of the optical laminated film of the present invention is provided.

The polarizing film that can be used in the present invention is not particularly limited as long as it has a function as a polarizer. For example, a polyvinyl alcohol (PVA) -based or polyene-based polarizing film can be used.
In the present invention, the polarizing film to be used preferably has a polarization degree of 99.9% or more, more preferably 99.95% or more. When the polarization degree of the polarizing film is in the above range, there is no reduction in contrast due to reflection, and the reproducibility when the liquid crystal display is black is excellent. As for the degree of polarization, the transmittance (H ₀ ) when two polarizing films are superposed so that their polarization axes are parallel to each other, and the transmittance (H ₉₀ ) when they are superposed orthogonally are JIS Z8701 It can be measured using a spectrophotometer with a 2-degree field of view (C light source), and can be obtained from the following equation using these. Note that H ₀ and H ₉₀ are Y values corrected for visibility.
Polarization degree (%) = [(H ₀ −H ₉₀ ) / (H ₀ + H ₉₀ )] ^1/2 × 100
The manufacturing method of a polarizing film is not specifically limited. As a method for producing a PVA-based polarizing film, a method of stretching uniaxially after iodine ions are adsorbed on a PVA-based film, a method of adsorbing iodine ions after stretching a uniaxially stretched PVA-based film, A method of simultaneously performing iodine ion adsorption and uniaxial stretching, a method of stretching a uniaxial film after dyeing a PVA film with a dichroic dye, a method of stretching a uniaxial film and then adsorbing with a dichroic dye, a PVA system The method of performing simultaneously dyeing | staining with a dichroic dye and uniaxial stretching to a film is mentioned. In addition, as a method for producing a polyene polarizing film, a method of heating and dehydrating in the presence of a dehydration catalyst after stretching a PVA film uniaxially, a method of stretching a polyvinyl chloride film uniaxially and then in the presence of a dehydrochlorination catalyst And publicly known methods such as heating and dehydrating.

The polarizing plate with an antireflection function of the present invention can be produced by laminating a polarizing film on the surface opposite to the surface on which the low refractive index layer of the base film of the optical laminated film of the present invention is provided. it can.
Lamination | stacking with a base film and a polarizing film can be bonded together using appropriate adhesion means, such as an adhesive agent and an adhesive. Examples of the adhesive or pressure-sensitive adhesive include acrylic, silicone, polyester, polyurethane, polyether, rubber, and the like. Among these, an acrylic type is preferable from the viewpoint of heat resistance and transparency.

  FIG. 2 shows a sectional view of the layer structure of the polarizing plate with antireflection function of the present invention. The polarizing plate 81 with an antireflection function shown in FIG. 2 is provided on the surface side of the base film 11 of the optical laminated film of the present invention where the low refractive index layer 31 is not provided, with an adhesive or pressure-sensitive adhesive layer 61 interposed therebetween. The polarizing film 71 and the protective film 41 are laminated.

  In the polarizing plate with antireflection function of the present invention, as shown in FIG. 2, another protective film (see FIG. 2) is provided on the surface on which the base film of the polarizing film is not laminated via an adhesive or a pressure-sensitive adhesive layer. 2 (see number 41 of 2) may be laminated. As a protective film, what consists of material with low optical anisotropy is preferable. The material having low optical anisotropy is not particularly limited, and examples thereof include cellulose esters such as triacetyl cellulose and polymer resins having an alicyclic structure, but transparency, low birefringence, and dimensional stability. A polymer resin having an alicyclic structure is preferable from the viewpoint of superiority. Examples of the polymer resin having an alicyclic structure include those described in the base film portion of the present invention. In the present invention, the protective film used may be isotropic or birefringent. When the protective film has birefringence, the protective film can also serve as a retardation plate to be laminated when forming the liquid crystal display device, and the thickness of the member can be reduced. Examples of the adhesive or pressure-sensitive adhesive include those similar to the adhesive or pressure-sensitive adhesive used for laminating the polarizing plate protective film and the polarizing film. The thickness of the polarizing plate with antireflection function of the present invention is not particularly limited, but is usually in the range of 60 μm to 2 mm.

  The optical product of the present invention includes the polarizing plate with an antireflection function of the present invention. Preferable specific examples of the optical product of the present invention include a liquid crystal display element and a touch panel used for a liquid crystal display device.

  As an example of an optical product including the polarizing plate with an antireflection function of the present invention, FIG. The liquid crystal display element shown in FIG. 3 includes a lower polarizing plate 91, a retardation plate 92, a liquid crystal cell 93, and a polarizing plate 81 with an antireflection function of the present invention in order from the bottom. The antireflection function-equipped polarizing plate 81 is formed on the liquid crystal cell 93 by being bonded to the polarizing plate surface via an adhesive or an adhesive (not shown). In the liquid crystal cell 93, for example, as shown in FIG. 4, two electrode substrates 95 each having a transparent electrode 94 are arranged at a predetermined interval with the transparent electrodes 94 facing each other, and a liquid crystal 96 is disposed in the gap. It is produced by enclosing. In FIG. 4, 97 is a seal.

The liquid crystal mode of the liquid crystal 96 is not particularly limited. As the liquid crystal mode, for example, a TN (Twisted Nematic) type, an STN (Super Twisted Nematic) type, a HAN (Hybrid Alignment Nematic) type, an MVA (Multiple Vertical Alignment) type, an IPS (Incremental Alignment) type, an IPS (Incremental Alignment) type, an IPS (Incremental Alignment) type. Bend) type.
Further, the liquid crystal display element shown in FIG. 3 has a normally white mode in which a bright display is applied when the applied voltage is low, a dark display when the applied voltage is high, a dark display when the applied voltage is low, and a normally black mode which is bright when the applied voltage is high. Can be used.
In order to form a liquid crystal display device using this liquid crystal display element, other members, for example, appropriate components such as a brightness enhancement film, a prism array sheet, a lens array sheet, a light guide plate, a light diffusion plate, and a backlight are appropriately used. One layer or two or more layers may be disposed at any position. These arrangement methods may be performed by the conventional arrangement method of the liquid crystal display device.

  The optical product of the present invention includes a polarizing plate with an antireflection function capable of achieving a low reflectance over a wide band. Therefore, particularly when used in a liquid crystal display device, the visibility is excellent (there is no glare or reflection) and the contrast of bright and dark display is excellent.

The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. Parts and% are based on weight unless otherwise specified.
Evaluation in this example is performed by the following method.
(1) Film thickness of the base film (reference film thickness, film thickness fluctuation value)
The film is cut every 100 mm in the length direction, and the cut film is measured every 0.48 mm in the width direction of the film using a contact web thickness meter (manufactured by Meisho Co., Ltd., RC-101). The arithmetic average value of the measured values is defined as a reference film thickness T (μm). The film thickness variation is calculated from the following equation, with the maximum value of the measured film thickness being T _MAX (μm) and the minimum value being T _MIN (μm).
Film thickness variation (%) = (T _MAX −T _MIN ) / T × 100
(2) Depth or height of die line of substrate film Using a non-contact three-dimensional surface shape / roughness measuring machine (manufactured by Zygo Co., Ltd.), with a field of view of 5.6 mm in width and 4.4 mm in length, the length is 480 Divide and divide the side by 640 and observe at 640 × 480 squares.
(3) Content of volatile component of base film 200 mg of the base film is put into a sample container of a glass tube having an inner diameter of 4 mm from which moisture and organic substances adsorbed on the surface are completely removed. Next, the container is heated at a temperature of 100 ° C. for 60 minutes, and the gas coming out of the container is continuously collected. The collected gas is analyzed by a thermal desorption gas chromatography mass spectrometer (TDS-GC-MS), and the total amount of components having a molecular weight of 200 or less is measured as a residual volatile component.
(4) Saturated water absorption rate of substrate film It is determined by immersing at 23 ° C. for 1 week and measuring the increased weight according to ASTM D530.
(5) Refractive Index of Hard Coat Layer and Low Refractive Index Layer Using a high-speed spectroscopic ellipsometer (manufactured by JA Woollam, M-2000U), measurement wavelength 245 to 1000 nm, incident angles 55 °, 60 ° and 65 Measured at °, and the value calculated based on the measured value is taken as the refractive index.
(6) Polarization degree of polarizing film The transmittance (H ₀ ) when two polarizing films are superposed so that their polarization axes are parallel, and the transmittance (H ₉₀ ) when they are superposed orthogonally, Measured using a spectrophotometer with a two-degree field of view (C light source) of JIS Z8701, and the degree of polarization is obtained from the following equation. Note that H ₀ and H ₉₀ are Y values corrected for visibility.
Polarization degree (%) = [(H ₀ −H ₉₀ ) / (H ₀ + H ₉₀ )] ^1/2 × 100
(6) Reflectance Using a spectrophotometer (manufactured by JASCO Corporation: “UV-visible near-infrared spectrophotometer V-570”), the reflection spectrum was measured at an incident angle of 5 °, and the reflectance at a wavelength of 430 to 700 nm. And the maximum value of the reflectance at a wavelength of 550 nm and the reflectance at a wavelength of 430 to 700 nm is defined as the reflectance at a wavelength of 430 to 700 nm.

(7) Visibility The obtained polarizing plate with antireflection function was cut out to an appropriate size (10 inches square), and the liquid crystal as shown in FIG. A liquid crystal display element is manufactured by incorporating into a display element. Next, a simple liquid crystal panel is prepared by placing the liquid crystal display element on a commercially available light box (trade name: Light Viewer-7000PRO, manufactured by Hakuba Photo Industry Co., Ltd.). The panel is visually observed and evaluated in the following three stages.
○: Glare (discomfort or difficulty in viewing due to excessively bright spots or surfaces in the field of view, meaning glare directly or indirectly received from the light source) or reflection Not at all.
Δ: Some glare or reflection is seen.
X: Glare and reflection can be seen on the entire screen.
The liquid crystal display element shown in FIG. 3 is configured by laminating a polarizing plate 81 with an antireflection function on one side of a liquid crystal cell 93 and a lower polarizing plate 91 via a retardation plate 92 on the other side. In the liquid crystal cell 93, after an alignment film is formed on the surface of the transparent electrode 94 of the electrode substrate 95 provided with the transparent electrode 94, the two transparent electrodes 94 face each other on the electrode substrate 95 provided with the transparent electrode 94. The liquid crystal 96 is formed by being disposed at a predetermined interval and enclosing the liquid crystal 96 in the gap. Reference numeral 97 denotes a seal. The liquid crystal display element is held by being fixed to a plastic frame.
In the polarizing plate 81 with an antireflection function, the optical laminated film 50 is laminated on the polarizing film 71 via the layer 61 made of an adhesive or an adhesive.

(8) Contrast The simple liquid crystal display panel created in (7) above is installed in a dark room, and the luminance at a position of 5 ° from the front at the time of dark display and light display is measured by a color luminance meter (manufactured by Topcon, color luminance). Measured using a total of BM-7). Then, the ratio between the brightness of the bright display and the brightness of the dark display (= brightness of the bright display / brightness of the dark display) is calculated and used as the contrast. The greater the contrast, the better the visibility.

(9) Scratch property The steel wool # 0000 is applied to the surface of the polarizing plate where the hard coat layer and the low refractive index are laminated, and the steel wool is subjected to 10 reciprocations with a load of 0.05 MPa applied. After that, the surface state of the polarizing plate is visually observed. ◯ indicates that there is no scratch, Δ indicates that a slight scratch is observed, and X indicates that a scratch is clearly observed.

(Production Example 1) Production of base film 1A A pellet of a norbornene polymer (product name “ZEONOR 1420R”, manufactured by Nippon Zeon Co., Ltd .; glass transition temperature 136 ° C., saturated water absorption less than 0.01% by weight) It dried for 4 hours at 110 degreeC using the distribute | circulated hot air dryer. And this pellet was coated with a coat hanger type T-die with a lip width of 650 mm with an average surface height Ra = 0.05 μm and a chrome-plated tip of the die lip provided with a leaf disk-shaped polymer filter (filtration accuracy 30 μm). Using a short shaft extruder, the substrate was melt extruded at 260 ° C. to obtain a base film having a width of 600 mm. The content of the volatile component of the obtained base film was 0.01% by weight or less, and the saturated water absorption was 0.01% by weight or less. The base film 1A had a reference film thickness of 40 μm, a film thickness variation of 2.3%, and a die line depth of 0.028 μm.

(Production Example 2) Preparation of hard coating agent 1 Antimony pentoxide modified alcohol sol (solid content concentration 30%, manufactured by Catalytic Chemical Co., Ltd.) 100 parts by weight, UV curable urethane acrylate (trade name: Shigamine UV7000B, Nippon Synthetic Chemical) 10 parts by weight) and a photopolymerization initiator (trade name: Irgacure 184, Ciba Geigy) 0.4 parts by weight were mixed to obtain an ultraviolet curable hard coat agent 1.

(Production Example 3) Preparation of hard coating agent 2 30 parts of an acrylic ultraviolet curable composition (manufactured by Nippon Kayaku Co., Ltd., trade name “KAYANOVAFOP-5000”) is mixed with a homogenizer, and is made of an ultraviolet curable resin composition. A coating agent 2 was obtained.

(Production Example 4) Preparation of polymethyl methacrylate of the high refractive index layer composition (Mitsubishi Rayon Co., ACRYPET VH) 32 parts, was mixed well methyl ethyl ketone 4900 parts until dissolved polymethylmethacrylate, TiO ₂ fine particles ( 68 parts of Cai Kasei, NanoTek TiO ₂ (rutile), toluene slurry 15%) were added and mixed well with a disper to obtain a composition for a high refractive index layer.

(Production Example 5) Preparation of coating solution 1 for low refractive index layer 90 parts of methyl methacrylate, 40 parts of n-butyl acrylate, 20 parts of γ-methacryloxypropyltrimethoxysilane, xylene in a reactor equipped with a reflux condenser and a stirrer After adding 130 parts and mixing, the mixture was heated to 80 ° C. with stirring. To this mixture, 4 parts of azobisisovaleronitrile dissolved in 10 parts of xylene was added dropwise over 30 minutes, and further at 80 ° C. for 5 hours. A silyl group-containing vinyl resin solution with a solid content concentration of 50% was obtained by reaction. The number average molecular weight in terms of polystyrene of this silyl group-containing vinyl resin by gel permeation chromatography was 12000, and it was estimated that the polymer contains an average of 6 silyl groups per molecule.
Next, a reactor equipped with a reflux condenser, 100 parts of methyltrimethoxysilane, 10 parts of dimethyldimethoxysilane, 50 parts of the silyl group-containing vinyl resin solution, 10 parts of aluminum tris (ethyl) acetoacetate, and 30 parts of isopropyl alcohol were added. After mixing, 30 parts of ion exchange water was added and reacted at 60 ° C. for 4 hours, and then cooled to room temperature, and 7 parts of acetylacetone was added to obtain a coating solution 1 for low refractive index layer.

(Production Example 6) Preparation of coating solution 2 for low refractive index layer 356 parts of methanol was added to 208 parts of tetraethoxysilane, 18 parts of water and 18 parts of 0.01N hydrochloric acid were mixed, and this was used with a disper. Mix well. The mixture was stirred for 2 hours in a constant temperature bath at 25 ° C., and the weight average molecular weight was adjusted to 850 to obtain a tetrafunctional silicone resin. Next, hollow silica isopropanol (IPA) dispersion sol (solid content: 20% by mass, average primary particle diameter: about 35 nm, outer shell thickness: about 8 nm, manufactured by Catalyst Kasei Kogyo Co., Ltd.) is used as the hollow silica fine particle component for this tetrafunctional silicone resin. , Hollow silica fine particles / 4-functional silicone resin (condensed compound equivalent) is added so that the mass ratio is 85/25 based on the solid content, and then diluted with methanol so that the total solid content becomes 10 mass%. Thus, a coating solution 2 for a low refractive index layer was obtained.

(Production Example 7) Preparation of coating solution 3 for low refractive index layer A tetramethoxysilane oligomer (trade name: Methyl silicate 511, manufactured by Colcoat Co.) and methanol were mixed to a weight ratio of 47:75. A liquid was prepared. Subsequently, water, ammonia water (ammonia 28% by weight), and methanol were mixed at a weight ratio of 60: 1.2: 97.2 to prepare a liquid B. And A liquid and B liquid were mixed by the weight ratio of 16:17, and the coating liquid 3 for low refractive index layers was obtained.

(Production Example 8) Preparation of Polarizing Film After a PVA film having a thickness of 45 μm (polymerization degree 2400, saponification degree 99.9%) was swollen in pure, mixing of 1% by weight of iodine and 3% by weight of potassium iodide The PVA film was dyed in an aqueous solution. Next, the film was immersed in a 4.5% by weight boric acid aqueous solution, stretched 5.3 times in the longitudinal direction, and subsequently immersed in a 5% by weight borax aqueous solution, so that the total stretching ratio in the longitudinal direction was 5.5 times. It extended | stretched so that it might become. After stretching, moisture on the film surface was removed and dried at 50 ° C. to prepare a polarizing film. The polarizing film had a thickness of 18 μm and a degree of polarization of 99.95%.

(Example 1)
Using a high-frequency oscillator (corona generator HV05-2, manufactured by Tamtec) on both surfaces of the base film 1A obtained in Production Example 1, a wire electrode having a diameter of 1.2 mm with an output voltage of 100%, an output of 250 W Then, a corona discharge treatment was performed for 3 seconds under the conditions of an electrode length of 240 mm and a work electrode distance of 1.5 mm to obtain a base film 1B whose surface was modified so that the surface tension was 0.072 N / m.
The hard coat agent 1 obtained in Production Example 2 was continuously applied to one side of the base film 1B using a die coater so that the thickness of the hard coat layer after curing was 5 μm. Subsequently, after drying this at 80 degreeC for 5 minute (s), the hard-coat agent was hardened by performing ultraviolet irradiation (integrated light quantity 300mJ / cm < ² >), and hard coat layer laminated | multilayer film 1C was obtained. The thickness of the hard coat layer after curing was 5 μm, the refractive index was 1.62, and the surface roughness was 0.2 μm.

  The low-refractive-index layer coating solution 2 obtained in Production Example 6 as a material constituting the low-refractive index layer on the hard coat layer laminated film 1C is applied by a wire bar coater, and is 120 ° C., 5 ° C. in air. By performing heat treatment for a minute, an optical laminated film 1D having a low refractive index layer having a thickness of 100 nm was obtained. The refractive index of this low refractive index layer was 1.34.

  The substrate obtained in Production Example 1 as the polarizing film and protective film obtained in Production Example 8 on the surface opposite to the surface on which the hard coat agent and the low refractive index layer of the obtained optical laminated film 1D were provided. The material film 1A was bonded together in this order via an acrylic adhesive (manufactured by Sumitomo 3M, “DP-8005 clear”) to obtain a polarizing plate 1E with an antireflection function. Optical performance was evaluated using this polarizing plate 1E. The evaluation results are shown in Table 1.

(Example 2)
The hard coat layer laminated film 1C obtained in Example 1 was put in a rotating chamber of a spin coater, and mixing of the coating solution 3 for low refractive index layer obtained in Production Example 7 was started on this film 1C. After a lapse of time, spin coating was performed for 10 seconds under the condition of a rotation speed of 700 rpm to form a gel-like thin film. The rotating chamber of the spin coater was previously set in a methanol atmosphere.
Next, this gel-like thin film was immersed in a curing solution having a composition in which water, 28% ammonia water, and methanol were mixed at a mass ratio of 162: 4: 640 for 5 minutes, and then cured at room temperature for one day. Further, the gel-like thin film thus cured was immersed in a 10% isopropanol solution of hexamethyldisilazane to perform a hydrophobic treatment.
Next, the gel-like thin film thus hydrophobized is immersed in isopropanol and washed, and then placed in a high-pressure vessel, and the inside of the high-pressure vessel is filled with liquefied carbon dioxide gas. By performing supercritical drying under conditions, an optical laminated film 2D in which a silica airgel thin film (low refractive index layer) having a film thickness of 100 nm was formed on the laminated film 1C was obtained. The refractive index of this silica airgel thin film (low refractive index layer) was 1.34.
A polarizing plate 2E with an antireflection function is obtained by laminating the polarizing film and the base film 1A in the same manner as in Example 1 except that the optical laminated film 2D is used instead of the optical laminated film 1D as the optical laminated film. It was. And optical performance was evaluated using this polarizing plate 2E. The evaluation results are shown in Table 1.

(Example 3)
An optical laminated film 3D is obtained by forming a hard coat layer in the same manner as in Example 1 except that the hard coat agent 2 obtained in Production Example 3 is used instead of the hard coat agent 1 as the hard coat agent. It was. At this time, the thickness of the hard coat layer was 5 μm, the refractive index was 1.53, and the surface roughness was 0.2 μm.
Next, a polarizing film 3E with an antireflection function is obtained by laminating the polarizing film and the base film 1A in the same manner as in Example 1, except that the optical laminated film 3D is used instead of the optical laminated film 1D as the optical laminated film. Got. Optical performance was evaluated using this polarizing plate 3E. The evaluation results are shown in Table 1.

(Example 4)
A hard coat layer laminated film 4C was formed by forming a hard coat layer in the same manner as in Example 1 except that the hard coat agent 2 obtained in Production Example 3 was used instead of the hard coat agent 1 as the hard coat agent. Obtained. The hard coat layer had a thickness of 5 μm, a refractive index of 1.53, and a surface roughness of 0.2 μm.
Next, a low refractive index layer coating solution 3 obtained in Production Example 7 was used as a low refractive index layer coating solution on the hard coat layer laminated film 4C. An optical laminated film 4D was obtained by forming a refractive index layer. The refractive index of this low refractive index layer was 1.34.
Next, a polarizing film 4E with an antireflection function is obtained by laminating the polarizing film and the base film 1A in the same manner as in Example 1 except that the optical laminated film 4D is used instead of the optical laminated film 1D as the optical laminated film. Obtained. Optical performance was evaluated using this polarizing plate 4E. The evaluation results are shown in Table 1.

(Example 5)
Instead of the base film 1A, a polyethylene terephthalate film (trade name “Cosmo Shine A4300”, thickness 50 μm, saturated water absorption 0.3% by weight, hereinafter referred to as “base film 2A” is used instead of the base film 1A. The optical laminated film 5D was obtained by forming a hard-coat layer and a low-refractive-index layer in the same manner as in Example 1 except that.
Next, a polarizing film 5E with an antireflection function is obtained by laminating the polarizing film and the base film 1A in the same manner as in Example 1 except that the optical laminated film 5D is used instead of the optical laminated film 1D as the optical laminated film. Obtained. Optical performance was evaluated using this polarizing plate 5E. The evaluation results are shown in Table 1.

(Example 6)
A polarizing plate using a triacetyl cellulose film instead of the base film 1A as the base film (trade name “Super High Contrast Polarizing Plate SKN-18243T”, Polarity 99.993%, hereinafter “Base” An optical laminated film 6D was obtained by forming a hard coat layer and a low refractive index layer in the same manner as in Example 1 except that the material film 3A ”was used. Since the polarizing film and the protective film are laminated on the optical laminated film 6D, the optical performance was evaluated using the polarizing film with the antireflection function as it is. The evaluation results are shown in Table 1.

(Comparative Example 1)
A hard coat layer was prepared in the same manner as in Example 1 except that the hard coat agent 2 obtained in Production Example 3 was used instead of the hard coat agent 1 on one side of the surface-modified base film 1B. A hard coat layer laminated film 7C was obtained. The hard coat layer had a thickness of 5 μm, a refractive index of 1.53, and a surface roughness of 0.2 μm.
This hard coat layer laminated film 7C was put into a rotating chamber of a spin coater, and the coating solution 3 for low refractive index layer obtained in Production Example 7 was put on this film 7C after 1 minute had elapsed and then rotated. Spin coating was performed for 10 seconds under the condition of several 700 rpm to form a gel-like thin film. The rotating chamber of the spin coater was previously set in a methanol atmosphere.
Next, the laminated film 7C on which this gel-like thin film was formed was heat-treated at 120 ° C. for 10 minutes in a gear oven, to obtain an optical laminated film 7D. The refractive index of the low refractive index layer of the optical laminated film 7D was 1.39.
Next, reflection was performed by laminating the polarizing film and the base film 1A in the same manner as in Example 1 except that the optical laminated film 7D was used instead of the optical laminated film 1D as the optical laminated film. A polarizing plate 7E with a prevention function was obtained. Optical performance was evaluated using this polarizing plate 7E. The evaluation results are shown in Table 1.

(Comparative Example 2)
A hard coat layer was formed on one side of the surface-modified base film 1B in the same manner as in Example 1 except that the hard coat agent 2 obtained in Production Example 3 was used instead of the hard coat agent 1 as the hard coat agent. A hard coat layer laminated film 8C was obtained by forming the film. The hard coat layer had a thickness of 5 μm, a refractive index of 1.53, and a surface roughness of 0.2 μm.
On this hard coat laminated film 8C, the high refractive index composition obtained in Production Example 4 was applied using a die coater so as to have a thickness of 127 nm, and dried at 80 ° C. The refractive index of this high refractive index layer was 1.70. A low refractive index layer is formed on the high refractive index layer in the same manner as in Example 1 except that the low refractive index layer coating liquid 1 obtained in Production Example 5 is used as the low refractive index layer coating liquid. By doing so, an optical laminated film 8D was obtained. The refractive index of the low refractive index layer was 1.33.
Subsequently, the polarizing plate 8E with an antireflection function was obtained by laminating the polarizing film and the base film 1A in the same manner as in Example 1 except that the optical laminated film 8D was used instead of the optical laminated film 1D as the optical laminated film. Obtained. Optical performance was evaluated using this polarizing plate 8E. The evaluation results are shown in Table 1.

From the results in Table 1, the following can be understood. According to the present invention, an optical laminated film obtained by laminating at least a hard coat layer and a low refractive index layer in this order on the surface of a base film comprising a transparent resin, the refractive index of the low refractive index layer Is 1.35 or less, an optical laminated film having a reflectance of 0.8% or less at a wavelength of 550 nm and a reflectance of 1.2% or less at a wavelength of 430 to 700 nm is excellent in antireflection property and scratch resistance. When used in a liquid crystal display device, it has excellent visibility and contrast for bright and dark display.
On the other hand, a low-refractive index layer having a refractive index exceeding 1.35 (Comparative Example 1) or a low-refractive index layer having a refractive index of 1.35 or less but having a reflectance within the scope of the present invention. What has been removed (Comparative Example 2) is not only inferior to scratching and visibility, but also has poor contrast in bright and dark display.

It is layer structure sectional drawing of the optical laminated film of this invention. It is layer structure sectional drawing of the polarizing plate with an antireflection function of this invention. It is layer structure sectional drawing of an example of a liquid crystal display provided with the polarizing plate with an antireflection function of this invention. FIG. 4 is a cross-sectional view of the layer structure of the liquid crystal cell shown in FIG. 3.

Explanation of symbols

  11: base film, 21: hard coat layer, 31: low refractive index layer, 41: protective film, 50: optical laminated film, 61: adhesive or pressure-sensitive adhesive layer, 71: polarizing film, 81: with antireflection function Polarizing plate, 91: lower polarizing plate, 92: retardation plate, 93: liquid crystal cell, 94: transparent electrode, 95: electrode substrate, 96: liquid crystal, 97: seal

Claims (8)

An optical laminated film obtained by laminating at least a hard coat layer and a low refractive index layer in this order on the surface of a base film comprising a transparent resin, wherein the refractive index of the low refractive index layer is 1.35 or less. An optical laminated film having a reflectance at a wavelength of 550 nm of 0.8% or less and a reflectance at a wavelength of 430 to 700 nm of 1.2% or less. The optical laminated film according to claim 1, wherein a depth or height of a die line of the base film made of the transparent resin is 0.1 μm or less. The optical laminated film according to claim 1, wherein the low refractive index layer is a layer made of airgel. The optical laminated film according to any one of claims 1 to 3, wherein the transparent resin is a resin selected from the group consisting of a polymer resin having an alicyclic structure, a cellulose resin, and a polyester resin. It is an antireflective protective film of an optical member, The optical laminated film of any one of Claims 1-4. 6. The optical laminated film according to claim 5, which is a polarizing plate protective film. A polarizing plate with an antireflection function, characterized in that a polarizing film is laminated on a surface opposite to the surface on which the low refractive index layer of the base film of the polarizing plate protective film according to claim 6 is provided. . An optical product comprising the polarizing plate with an antireflection function according to claim 7.

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