JP2016071157A - Low refractive index film-forming composition, low refractive index film, film with low refractive index film, and touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low refractive index film-forming composition capable of providing a film with antiblocking property without having to coat a back surface with a special antiblocking agent, and to provide a low refractive index film, film with the low refractive index film, and a touch panel.SOLUTION: A low refractive index film-forming composition of the present invention contains silicon alkoxide, and a cross-linking compound having at least either of one or more methacryloyl groups and acryloyl groups in a molecule.SELECTED DRAWING: None

Description

  The present invention relates to a composition for forming a low refractive index film, a low refractive index film, a film with a low refractive index film, and a touch panel.

Antireflection members, particularly antireflection films, are generally used in image display devices such as cathode ray tube display devices (CRT), plasma display panels (PDP), and liquid crystal display devices (LCD). In order to prevent image reflection, it is arranged on the outermost surface of the image display device so as to reduce the reflectance by using the principle of optical interference.
In addition, an index matching (IM) (refractive index adjustment) film, which is one of antireflection members, is mounted on various mobile devices such as a mobile phone and a portable music terminal using a capacitive touch panel. The IM film, like the antireflection film, is laminated with layers with different refractive indexes, and the transmittance and color are controlled using light interference, making the pattern shape of the conductive film difficult to see and visibility. It is provided to improve.
The IM film has various configurations depending on the optical design, but generally has a configuration in which a high refractive index layer and a low refractive index layer are laminated (see, for example, Patent Documents 1 and 2).

The low refractive index layer for IM film is often provided with an ultrathin film having a thickness of 5 nm to 200 nm, and precise film formation control is required. Therefore, the low refractive index layer for IM film is one of the layers that are very difficult to form. Under these circumstances, conventionally, the low refractive index layer is often provided by a dry method such as sputtering, not by a wet coating method using a coater. However, due to advances in coating technology in recent years, it has become possible to control the film thickness by the wet coating method even for ultra-thin films.
When an optical adjustment layer such as a low refractive index film is formed on a thermoplastic film such as a PET film by a wet coating method, the film wound in a roll shape (roll film) is unwound and formed in the manufacturing process. Again, the film may be wound and stored.
When another layered body is stacked on a base material layer such as a PET film on which an optical adjustment layer is formed, an adhesive force or a chemical force acts between the layers to be in an attached state. Therefore, when using each layered body, it is necessary to have a force for peeling off each layered body, or it becomes difficult to peel off due to strong adhesion, or if it is forcibly removed, May cause blocking troubles such as breakage. In addition, such a coating film that is likely to cause blocking trouble is caught between the coating films when they are wound after film formation, so that the film cannot be wound well, and the roll film is locally stressed or the film is wound in an irregular manner. It may cause defects such as wrinkles on the film.

  The optical adjustment layer formed by the conventional dry method does not contain an organic component in the composition constituting the layer, and is composed only of an inorganic component. Therefore, even if the film is wound in a roll shape, Since the inorganic component does not have viscoelasticity, the optical adjustment layer and the film are hardly attached. However, in the wet coating method, since the composition constituting the layer often contains an organic component as a binder, there is a problem that the adhesion state between the optical adjustment layer and the film is more likely to occur due to the viscoelasticity of the organic component. there were. There is also a method of forming a low refractive index layer made of an inorganic component by coating using a sol-gel method. According to this method, although the adhesion state of the optical adjustment layer and the film can be avoided, the optical adjustment layer has a problem that the adhesion to the underlying resin layer (high refractive index layer) becomes poor.

  Up to now, a hard coat layer has been provided on the back side of the optical adjustment layer and the base material, and the hard coat layer contains a silicone compound to improve the anti-blocking property by improving the film surface slipperiness. Is disclosed (see, for example, Patent Document 3). In addition, a method is disclosed in which organic fine particles are mixed in a hard coat layer to form irregularities on the surface of the hard coat layer to prevent mirror surface adhesion and improve anti-blocking properties (see, for example, Patent Document 4). ). Furthermore, a method is disclosed in which inorganic fine particles are mixed in the hard coat layer to form irregularities on the surface of the hard coat layer to prevent mirror surface adhesion and improve anti-blocking properties (see, for example, Patent Document 5). ).

JP 2011-142089 A JP 2011-136562 A JP 2007-224234 A JP 2007-238732 A JP 2004-042653 A

However, in the method of Patent Document 3, after winding the film, the silicone compound oozes out on the surface of the hard coat layer, and it moves to the winding back surface (optical adjustment layer). There is a problem that a problem such as occurrence of repelling occurs.
On the other hand, although the method using organic fine particles as in Patent Document 4 is excellent in anti-blocking property, the cross-linked organic fine particles having excellent solvent resistance have a problem of high production cost and high cost. In addition, the method using inorganic fine particles as in Patent Document 5 is excellent in anti-blocking properties and can reduce the manufacturing cost, but has a problem that haze increases due to the refractive index and particle size of the inorganic fine particles.

  The present invention has been made in view of the above circumstances, and has low adhesion that has adhesion and can impart anti-blocking properties to a film without forming a special anti-blocking agent on the back surface. An object of the present invention is to provide a composition for forming a refractive index film, a low refractive index film, a film with a low refractive index film, and a touch panel.

  According to the present invention, a low refractive index film contains silicon alkoxide and a glassy material obtained by polymerizing a crosslinkable compound having at least one methacryloyl group and acryloyl group in the molecule. Therefore, the viscoelasticity of the material is lower than when the material is composed of only an organic material, so even if the materials are brought into contact with each other, the frictional resistance does not increase, and a low refractive index film is provided while maintaining adhesion. The present inventors have found that the antiblocking property of a film can be improved, and have completed the present invention.

  That is, the composition for forming a low refractive index film of the present invention comprises silicon alkoxide and a crosslinkable compound having at least one methacryloyl group and acryloyl group in the molecule. And

  The low refractive index film of the present invention comprises a compound having a siloxane bond and an acrylic resin, has a refractive index of 1.37 or more and 1.51 or less, and a dynamic friction coefficient when the film surfaces are brought into contact with each other. The static friction coefficient is 0.6 or less, and the arithmetic mean roughness Ra of the surface is 3 nm or less.

The film with a low refractive index film of the present invention is a film with a low refractive index film in which a hard coat film and a low refractive index film are provided in order from one main surface of the substrate film, The refractive index film is the low refractive index film of the present invention, and the arithmetic average roughness Ra of the surface of the low refractive index film is 3 nm or less.
It is preferable that a high refractive index film having a refractive index of 1.51 or more and 1.85 or less is provided between the hard coat film and the low refractive index film.

  The film with a low refractive index film of the present invention is provided with a high refractive index hard coat film having a refractive index of 1.51 or more and 1.85 or less and a low refractive index film in order from one main surface of the base film. A film with a low refractive index film, wherein the low refractive index film is the low refractive index film of the present invention, and an absolute value of a refractive index difference between the base film and the high refractive index hard coat film. Is 0 or more and 0.48 or less, and the arithmetic average roughness Ra of the surface of the low refractive index film is 3 nm or less.

  The touch panel of the present invention comprises at least one of the low refractive index film of the present invention and the film with a low refractive index film of the present invention.

  The composition for forming a low refractive index film of the present invention contains silicon alkoxide and a crosslinkable compound having at least one methacryloyl group and acryloyl group in the molecule. A low refractive index film excellent in blocking property and adhesion can be obtained.

  Since the low refractive index film of the present invention contains a compound having a siloxane bond and an acrylic resin, a film excellent in antiblocking property and adhesion can be obtained when provided on a base film.

  Since the film with a low refractive index film of the present invention includes the low refractive index film of the present invention, it is excellent in anti-blocking property and adhesion.

  Since the touch panel of the present invention includes at least one of the low refractive index film of the present invention and the film with the low refractive index film of the present invention, a phenomenon in which the electrode portion can be seen can be suppressed.

The form for implementing the composition for low refractive index film | membrane formation of this invention, the film with a low refractive index film, a film with a low refractive index film, and a touch panel is demonstrated.
The following embodiments are specifically described for better understanding of the gist of the invention, and do not limit the present invention unless otherwise specified.

[Composition for forming low refractive index film]
The composition for forming a low refractive index film according to this embodiment contains silicon alkoxide and a crosslinkable compound having at least one methacryloyl group and acryloyl group in the molecule.

"Silicon alkoxide"
The silicon alkoxide used in the composition for forming a low refractive index film of the present embodiment is at least one compound represented by the following formula (I) or a hydrolyzate thereof.
Si (OR ₁ ) _m R _2n (I)
(In the formula, R ₁ and R ₂ are alkyl groups, m is an integer of 1 to 4, n is an integer of 0 to 3, and m + n = 4.)
Examples of such silicon alkoxides include tetraalkoxysilane compounds, alkyltrialkoxysilane compounds, dialkyldialkoxysilane compounds, and other organosilicon compounds. Preferably, these compounds are hydrolyzed. The resulting silica sol is used. These may be used alone or in combination of two or more. The reason why such a silicon alkoxide is used is that the refractive index n of silica is as low as n = 1.45, and the low refractive index film formed of silica sol obtained by hydrolyzing the above compound has a film strength. This is because it is strong and has excellent durability required for the low refractive index film.

Specific examples of the silicon alkoxide include a silicone coupling agent and silicone oil.
Examples of the silicon coupling agent include methyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, methylmethoxysilane, n-propyltrimethoxysilane, n-butyltriethoxysilane, n-hexyltrimethoxysilane, n -Hexyltriethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane and other silane coupling agents, vinyltrimethoxysilane, vinyltriethoxysilane and other vinylsilane coupling agents Aminosilane coupling agents such as 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane Acryloxysilane coupling agents, methacryloxysilane coupling agents such as 3-methacryloxypropyltrimethoxysilane, mercaptosilane coupling agents such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane, γ- Examples thereof include glycidoxypropyltrimethoxysilane.
Examples of the silicone oil include dimethyl silicone oil, methyl hydrogen silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, polyether-modified silicone oil, and amino-modified silicone oil.
Among these, in particular, acryloxysilane coupling agents such as 3-acryloxypropyltrimethoxysilane, methacryloxysilane coupling agents such as 3-methacryloxypropyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane By mixing at least one selected from the group during the hydrolysis reaction of the silicon alkoxide, the affinity between the silicon alkoxide and the resin obtained by curing the crosslinkable compound is significantly improved, and the adhesion is increased. Therefore, the low refractive index film can obtain a high film strength.

"Crosslinkable compounds"
Examples of the crosslinkable compound having at least one methacryloyl group and acryloyl group in the molecule used in the composition for forming a low refractive index film of the present embodiment include one or more methacryloyl groups and acryloyl in the molecule. Although it will not specifically limit if it has at least 1 type of group, The polyfunctional acrylate excellent in reactivity, transparency, a weather resistance, hardness, etc. is desirable. Specific examples of the polyfunctional acrylate include, for example, (meth) trimethylolpropane triacrylate, (meth) ditrimethylolpropane tetraacrylate, (meth) pentaerythritol triacrylate, (meth) pentaerythritol tetraacrylate, (meth) dipenta Examples include polyol polyacrylates such as erythritol hexaacrylate, epoxy (meth) acrylates, polyester (meth) acrylates, urethane acrylates, and polysiloxane acrylates. These polyfunctional acrylates may be used alone or in combination of two or more.

The compounding ratio of the silicon alkoxide and the crosslinkable compound is preferably in the range of 5:95 to 90:10 by mass ratio. When the compounding ratio of the silicon alkoxide is less than 5% by mass, the anti-blocking property is lowered. On the other hand, when the compounding ratio of the silicon alkoxide exceeds 90% by mass, the low refractive index film and the substrate are adhered when the low refractive index film made of the composition for forming a low refractive index film of the present embodiment is laminated on the substrate. Sex cannot be maintained.
In addition, the adhesiveness in this embodiment means that evaluation is performed based on JIS-K05600-5-6, and the JIS evaluation classification result is 0-2.

"Inorganic fine particles"
The composition for forming a low refractive index film of the present embodiment may be composed only of the above silicon alkoxide and a crosslinkable compound. However, when the refractive index is further reduced, inorganic fine particles with a low refractive index are used. It may be added.
As the inorganic fine particles, those having an average primary particle diameter of 3 nm to 100 nm are preferable. Here, the reason why the lower limit of the average primary particle diameter of the inorganic fine particles is 3 nm is that it is difficult to stably produce inorganic fine particles having an average primary particle diameter of less than 3 nm in the current technology. This is because it is limited and very expensive. In addition, fine particles having an average primary particle diameter of less than 3 nm have a large specific surface area, so that a large amount of dispersant must be used, and the refractive index cannot be lowered sufficiently. On the other hand, the reason why the upper limit of the average primary particle size of the inorganic fine particles is 100 nm is that the Mie scattering generated by the inorganic fine particles having a dispersed particle size exceeding 100 nm is highly scattering, and the loss of transmitted light due to Mie scattering is ignored. Because it becomes impossible. By setting the upper limit of the average primary particle diameter of the inorganic fine particles to 100 nm, it is possible to suppress the loss of transmitted light due to Mie scattering.

  In the present embodiment, the “average primary particle size” means the particle size of each particle itself. As a measuring method of the average primary particle diameter, the major axis of each metal oxide particle, for example, 100 or more metal oxide particles, preferably using a scanning electron microscope (SEM), a transmission electron microscope (TEM), etc. Includes a method of measuring the major axis of each of the 500 metal oxide particles and calculating the arithmetic average value thereof.

The refractive index of the inorganic fine particles is preferably 1.17 or more and 1.40 or less, more preferably 1.17 or more and 1.35 or less, and further preferably 1.17 or more and 1.30 or less. .
The inorganic fine particles are not particularly limited as long as the above refractive index is satisfied, but mesoporous silica fine particles having voids on the inner side are particularly preferable. Note that the refractive index of the mesoporous silica fine particles represents the refractive index of the entire particles, and does not represent the refractive index of only the outer shell silica forming the mesoporous silica fine particles. At this time, when the radius of the void in the mesoporous silica fine particles is a and the radius of the outer shell of the mesoporous silica fine particles is b, the porosity x represented by the following formula (II) is preferably 10 to 60%, more preferably Is 20 to 60%, more preferably 30 to 60%.
Formula (II): x = (4πa 3/3) / (4πb 3/3) × 100
If the hollow silica fine particles are made to have a lower refractive index and a higher porosity, the outer shell thickness is reduced and the strength of the particles is reduced. Therefore, from the viewpoint of scratch resistance, the low refractive index is less than 1.17. The particles do not hold. A method for producing mesoporous silica fine particles is described in, for example, Japanese Patent Application Laid-Open Nos. 2001-233611 and 2002-79616.

  The content of the inorganic fine particles in the composition for forming a low refractive index film of the present embodiment may be appropriately adjusted according to the target refractive index, but is preferably 0% by mass or more and 90% by mass or less, and 0% by mass. % To 70% by mass is more preferable.

"Initiator, additive"
The composition for forming a low refractive index film of the present embodiment may appropriately contain a photopolymerization initiator, a monomer having one or two functional groups, and the like.
The kind and amount of the photopolymerization initiator are appropriately selected according to the crosslinkable compound used. As the photopolymerization initiator, for example, benzophenone, diketone, acetophenone, benzoin, thioxanthone, quinone, benzyldimethyl ketal, alkylphenone, acylphosphine oxide, phenylphosphine oxide, and the like are known. The photoinitiator of this is mentioned.
In addition, the composition for forming a low refractive index film of the present embodiment includes an antifoaming agent within a range that does not impair the effects of the invention in order to improve the characteristics of the composition for forming a low refractive index film and the low refractive index film. In addition, various general additives such as an antioxidant, an ultraviolet absorber, a light stabilizer, and a polymerization inhibitor may be appropriately contained.
However, it is desirable not to use the silicone compound because it moves to the surface of the coating film and moves back to the back surface after winding the film, which may adversely affect post-processing.

"Diluent"
In order to satisfy the following viscosity, the composition for forming a low refractive index film of the present embodiment may appropriately contain an organic solvent as a diluent.
The organic solvent is not particularly limited as long as it has good compatibility with the other components of the composition for forming a low refractive index film of the present embodiment. For example, an aromatic solvent such as an alcohol solvent, toluene, xylene, etc. Examples include solvents, aliphatic solvents such as hexane and heptane, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ether solvents, ester solvents, amide solvents, cellosolve solvents, ether ester solvents and the like. These organic solvents may be used individually by 1 type, and may be used in combination of 2 or more types.

The viscosity of the composition for forming a low refractive index film of the present embodiment is preferably 0.2 mPa · s or more and 500 mPa · s or less, and more preferably 0.5 mPa · s or more and 200 mPa · s or less. .
When the viscosity of the composition for forming a low refractive index film is less than 0.2 mPa · s, when the coating film is formed using this composition for forming a low refractive index film, the film thickness of the coating film becomes too thin. It is not preferable because it is difficult to control the thickness. On the other hand, when the viscosity of the composition for forming a low refractive index exceeds 500 mPa · s, the viscosity is too high, and handling of the composition for forming a low refractive index film at the time of coating becomes difficult.

  In this embodiment, as a method for measuring the viscosity of the composition for forming a low refractive index film, the Ubbelohde method of Japanese Industrial Standard JIS Z8803 can be mentioned.

As a method for producing the composition for forming a low refractive index film of the present embodiment, a curable resin composition comprising silicon alkoxide and a crosslinkable compound having at least one methacryloyl group and acryloyl group in the molecule. There is no particular limitation as long as it is a method that can uniformly mix a photopolymerization initiator, a diluent, and, if necessary, an additive and the like.
In the method for producing the composition for forming a low refractive index film of the present embodiment, examples of the mixing device used for mixing the above components include a stirrer, a self-revolving mixer, a homogenizer, an ultrasonic homogenizer, and the like. It is done.

  According to the composition for forming a low refractive index film of the present embodiment, it contains silicon alkoxide and a crosslinkable compound having at least one methacryloyl group and acryloyl group in the molecule. When the low refractive index film is formed, the proportion of the glassy material (acrylic resin) in the low refractive index film can be increased, so that a low refractive index film excellent in antiblocking property and adhesion can be obtained. .

[Low refractive index film]
The low refractive index film of this embodiment contains a compound having a siloxane bond and an acrylic resin, has a refractive index of 1.37 or more and 1.51 or less, and a dynamic friction coefficient when the film surfaces are brought into contact with each other. And the coefficient of static friction is 0.6 or less, and the arithmetic average roughness Ra of the surface is 3 nm or less.

The low refractive index film of the present embodiment has a refractive index of 1.37 or more and 1.51 or less, and more preferably 1.40 or more and 1.50 or less.
By making the refractive index within the above range, the low refractive index film of the present embodiment has a function as an optical adjustment film, and when applied to an image display device, the visibility of the display screen is good. can do. If the refractive index of the low refractive index film is lowered to less than 1.37, the proportion of inorganic fine particles in the composition becomes too high, causing problems in film formability and film strength. On the other hand, when the refractive index of the low refractive index film exceeds 1.51, it does not function as a low refractive index film.

In the low refractive index film of the present embodiment, when the film surfaces are brought into contact with each other, the dynamic friction coefficient when the film surfaces are rubbed together is 0.6 or less and 0.4 or less. Is preferred.
When the dynamic friction coefficient exceeds 0.6, the low refractive index film is caught when unwinding or winding the film provided with the low refractive index film. The film may be wound up by a crack and cause defects such as wrinkles on the film. Moreover, when a dynamic friction coefficient exceeds 0.6, blocking will generate | occur | produce at the time of unwinding after storage, films will stick, and possibility that a layer breaks will become high.

Moreover, the low-refractive-index film of this embodiment has a static friction coefficient of 0.6 or less and preferably 0.5 or less when the film surfaces are brought into contact with each other.
When the coefficient of static friction exceeds 0.6, the film has a tackiness when the films are rubbed together, and when the coated film is wound up with a roll, it becomes sticky or stuck. Therefore, the film may be caught when the film is wound and the film cannot be wound uniformly, or the film may be broken when the film is unwound.

The low refractive index film of the present embodiment has a surface arithmetic average roughness Ra of 3 nm or less, preferably 2 nm or less, and more preferably 1 nm or less.
If the arithmetic average roughness Ra of the surface of the low refractive index film exceeds 3 nm, when an electrode is formed on the low refractive index film, unevenness cannot be applied to form an optimum film, and the electrode performance is reduced. Since it may deteriorate, it is not preferable.
Further, the low refractive index film of the present embodiment preferably has a peak-to-valley value of 30 nm or less, more preferably 20 nm or less, when scanning a 20 μm × 20 μm range with an atomic force microscope. More preferably, it is as follows. A smaller peak-to-valley value is preferable because there is no unevenness on the film surface.

The low refractive index film of this embodiment preferably has a film thickness of 5 nm to 100 nm, more preferably 10 nm to 150 nm.
By setting the film thickness of the low refractive index film within the above range, the low refractive index film of the present embodiment can reduce the reflected light in the visible light wavelength region, for example, when applied to an image display device The visibility of the display screen can be improved. If the film thickness of the low refractive index film is less than 5 nm, it is difficult to form the low refractive index film. On the other hand, when the film thickness of the low refractive index film exceeds 100 nm, the surface of the low refractive index film is unclear, which is not preferable.

The low refractive index film of the present embodiment preferably has a haze value of 1.5% or less, and more preferably 1.0% or less.
In the present embodiment, the “haze value” is a ratio (%) of diffuse transmitted light to total light transmitted light, and a haze meter NDH-2000 (manufactured by Nippon Denshoku Co., Ltd.) is used on the basis of air. It means a value measured based on the industrial standard JIS-K-7136.
Specifically, the haze value of the base material provided with the low refractive index film is measured as a blank, and the difference from the haze value of the test piece in which the low refractive index film is provided on the base material is low. The haze value of only the refractive index film is measured.

The method for producing a low refractive index film according to the present embodiment includes a step of forming a coating film by applying the composition for forming a low refractive index film according to the above-described embodiment onto an object to be coated such as a base material, And a step of curing the coating film.
Examples of the coating method in the step of forming the coating film include bar coating, flow coating, dip coating, spin coating, roll coating, spray coating, meniscus coating, gravure coating, and suction coating. A normal wet coating method such as a construction method or a brush coating method is used.

As a curing method in the step of curing the coating film, a method of irradiating the coating film with energy rays and photocuring is used.
The energy ray used for photocuring is not particularly limited as long as the coating is cured. For example, energy such as ultraviolet rays, far infrared rays, near ultraviolet rays, infrared rays, X rays, γ rays, electron beams, proton rays, neutron rays, etc. A line is used. Among these energy rays, it is preferable to use ultraviolet rays because the curing speed is fast and the device is easily available and handled.
By photocuring the coating film, the crosslinkable compound is polymerized to produce an acrylic resin, and a low refractive index film excellent in strength such as anti-blocking property and scratch resistance can be obtained.

In the case of curing by ultraviolet irradiation, ultraviolet rays are applied at an energy of 100 to 3,000 mJ / cm ² using a high-pressure mercury lamp, metal halide lamp, xenon lamp, chemical lamp, etc. that generates ultraviolet rays in a wavelength band of 200 nm to 500 nm. The method of irradiating etc. is mentioned.

  According to the low refractive index film of this embodiment, since it is formed using the composition for forming a low refractive index film of this embodiment, the proportion of acrylic resin (glassy material) can be increased. Therefore, the acrylic resin can lower the viscoelasticity of the coating film and is excellent in anti-blocking property and adhesion.

[Film with low refractive index film]
(First embodiment)
The film with a low refractive index film of the present embodiment has a base film and a hard coat film and a low refractive index film provided in this order from one main surface of the base film, and has a low refractive index. The film is the low refractive index film of the above-described embodiment, and the arithmetic average roughness Ra of the surface of the low refractive index film is 3 nm or less.
Here, the surface of the low refractive index film is a surface opposite to the surface in contact with the hard coat film in the low refractive index film.

In the film with a low refractive index film of the present embodiment, the arithmetic average roughness Ra of the surface of the low refractive index film is 3 nm or less, preferably 2 nm or less, and more preferably 1 nm or less.
When the arithmetic average roughness Ra of the surface of the low refractive index film exceeds 3 nm, when forming an electrode on the surface of the low refractive index film, the unevenness on the surface of the low refractive index film affects the optimum film formation. This is not preferable because the electrode performance may be deteriorated.

  In the film with a low refractive index film of the present embodiment, the composition for forming a low refractive index film of the above-described embodiment is formed on one main surface of the base film (one main surface of the base film using a known coating method). A low-refractive-index film is formed by forming a coating film on the hard coat film formed on) and photocuring the coating film.

The substrate film is not particularly limited as long as it is a plastic substrate. For example, polyethylene terephthalate, triacetyl cellulose, acrylic, acrylic-styryl copolymer, acrylonitrile-butadiene-styrene copolymer, polystyrene, polyethylene, polypropylene , Polycarbonate, vinyl chloride and the like are used.
The base film may be in the form of a sheet or film, but is preferably in the form of a film.

The hard coat film is provided on the lower layer of the low refractive index film, that is, one main surface of the base film (between the base film and the low refractive index film) in order to prevent the base film from being damaged.
The hard coat film is not particularly limited as long as it has the ability to prevent the base film from being scratched. Even if the hard coat film is formed of a composition for forming an ultraviolet curable hard coat film, It may be formed of a composition for forming a coat film. The hard coat film may contain particles.

The refractive index of the hard coat film is preferably 1.51 or more and 1.85 or less, and more preferably 1.51 or more and 1.70 or less.
By setting the refractive index of the hard coat film within the above range, the refractive index of the hard coat film becomes close to the refractive index of the base film to be formed, and optical interference between the base film and the hard coat film is reduced. A hard coat film that is suppressed and has good visibility can be obtained.

The hard coat film preferably has a thickness of 100 nm to 10 μm, more preferably 300 nm to 5 μm.
By setting the film thickness of the hard coat film within the above range, hard coat performance and production stability can be obtained. When the thickness of the hard coat film is less than 100 nm, the hard coat performance is insufficient. On the other hand, if the thickness of the hard coat film exceeds 10 μm, the film may curl due to curing shrinkage and may not be wound well.

The film with a low refractive index film of the present embodiment preferably has a high refractive index film between the hard coat film and the low refractive index film, and the refractive index of the high refractive index film is 1.51 or more and It is preferably 1.85 or less and 0.1 or more larger than the refractive index of the hard coat film.
By setting the refractive index of the high refractive index film within the above range, the film with a low refractive index film of the present embodiment has good optical characteristics and good visibility of the display device. . For example, when applied to a touch panel, the bone appearance phenomenon can be suppressed and the visibility of the display screen can be improved.
Note that the refractive index of the high refractive index film must be larger than the refractive index of the low refractive index film, but is appropriately set according to the optical design.

A high refractive index film | membrane is obtained by apply | coating the composition for high refractive index film | membrane containing the particle | grains of a high refractive index on one main surface of a base film, for example.
The high refractive index particles are not particularly limited. For example, particles such as zirconium oxide, titanium oxide, aluminum oxide, zinc oxide, tin oxide, antimony-doped tin oxide, and tin-doped indium oxide are used.
The solvent for the composition for forming a high refractive index film is not particularly limited, and an organic solvent and water can be used alone or in combination.
If necessary, additives such as colloidal silica, inorganic polymers, resins, leveling agents, and surfactants may be added to the high refractive index film forming composition.

The high refractive index film preferably has a thickness of 5 nm to 200 nm, more preferably 10 nm to 100 nm.
By setting the film thickness of the high refractive index film within the above range, the optical characteristics are improved and, for example, effects such as index matching can be exhibited.

The film with a low refractive index film of the present embodiment preferably has a haze value of 2.0% or less, more preferably 1.1% or less, when measured on the basis of air. More preferably, it is% or less.
In the present embodiment, the “haze value” means a value similar to that of the low refractive index film of the above-described embodiment.

  According to the film with a low refractive index film of the present embodiment, since the low refractive index film of the above-described embodiment is provided, the anti-blocking property and the adhesiveness are excellent.

(Second embodiment)
The film with a low refractive index film of the present embodiment is a base film and a high refractive index hard coat having a refractive index of 1.51 or more and 1.85 or less provided in order from one main surface of the base film. A low refractive index film is the low refractive index film of the above-described embodiment, and the absolute value of the refractive index difference between the base film and the high refractive index hard coat film is It is 0 or more and 0.48 or less, and the arithmetic average roughness Ra of the surface of the low refractive index film is 3 nm or less.
Here, the surface of the low refractive index film is a surface on the opposite side to the surface in contact with the high refractive index hard coat film in the low refractive index film.

  As a base film, the thing similar to the above-mentioned 1st embodiment is used.

In order to prevent the base film from being damaged, the high refractive index hard coat film is formed on the lower layer of the low refractive index film, that is, on one main surface of the base film (between the base film and the low refractive index film). Provided.
The high refractive index hard coat film is not particularly limited as long as it has the ability to prevent damage to the base film, and even if it is formed of an ultraviolet curable high refractive index hard coat film forming composition. Further, it may be formed of a thermosetting high refractive index hard coat film forming composition. The high refractive index hard coat film may contain particles.

The refractive index of the high refractive index hard coat film is preferably 1.51 or more and 1.85 or less. Moreover, it is preferable that a refractive index difference with the base film mentioned above is small.
By setting the refractive index of the high refractive index hard coat film within the above range, optical interference between the base film and the hard coat film is suppressed, and a high refractive index hard coat film with good visibility is obtained.

The absolute value of the difference in refractive index between the base film and the high refractive index hard coat film is 0 or more and 0.48 or less, and preferably 0.1 or more and 0.3 or less.
By setting the absolute value of the difference in refractive index between the base film and the high refractive index hard coat film within the above range, desired optical characteristics can be obtained, for example, a good index matching layer can be obtained. When the absolute value of the refractive index difference between the base film and the high refractive index hard coat film exceeds 0.48, a low refractive index film having a refractive index of less than 1.37 must be formed. However, in order to form such a low refractive index film, since the ratio of silicon alkoxide in the composition for forming a low refractive index film is excessively increased, film formability and film strength are inferior.

The high refractive index hard coat film preferably has a film thickness of 100 nm or more and 10 μm or less, and more preferably 0.5 μm or more and 5 μm or less.
By setting the film thickness of the high refractive index hard coat film within the above range, hard coat performance and production stability can be obtained. When the film thickness of the high refractive index hard coat film is less than 100 nm, the hard coat performance is insufficient. On the other hand, if the film thickness of the high refractive index hard coat film exceeds 10 μm, the film may curl due to curing shrinkage and may not be wound well.

  In the film with a low refractive index film of the present embodiment, the composition for forming a low refractive index film of the above-described embodiment is formed on one main surface of the base film (one main surface of the base film using a known coating method). A low-refractive-index film is formed by forming a coating film on the high-refractive-index hard coat film formed above) and photocuring the coating film.

In the film with a low refractive index film of the present embodiment, the arithmetic average roughness Ra of the surface of the low refractive index film is 3 nm or less, preferably 2 nm or less, and more preferably 1 nm or less.
If the arithmetic average roughness Ra of the surface of the low refractive index film exceeds 3 nm, the surface of the low refractive index film is affected by the unevenness of the surface of the low refractive index film, so that an optimum film is formed. The film cannot be formed, and the electrode performance may deteriorate.

The film with a low refractive index film of the present embodiment preferably has a haze value of 2.0% or less, more preferably 1.1% or less, when measured on the basis of air. More preferably, it is% or less.
In the present embodiment, the “haze value” means a value similar to that of the low refractive index film of the above-described embodiment.

  According to the film with a low refractive index film of the present embodiment, since the low refractive index film of the above-described embodiment is provided, the anti-blocking property and the adhesiveness are excellent.

[Touch panel]
The touch panel of this embodiment includes at least one of the low refractive index film of the above-described embodiment and the film with a low refractive index film of the above-described embodiment.

In the touch panel, when the refractive index difference between the ITO electrode and the transparent base material (plastic base material such as polyethylene terephthalate) is large, a so-called bone appearance phenomenon occurs in which the ITO electrode portion is easily visible.
Therefore, the low refractive index film of this embodiment having a refractive index of 1.37 or more and 1.51 or less, a film with a low refractive index film having a high refractive index film having a refractive index of 1.51 or more and 1.85 or less, Alternatively, by providing a film with a low refractive index film having a high refractive index hard coat film having a refractive index of 1.51 or more and 1.85 or less as a layer between the transparent substrate and the ITO electrode, The difference in refractive index of the ITO electrode can be relaxed to suppress the bone appearance phenomenon.

  The method for providing at least one of the low refractive index film of the above-described embodiment and the film with the low refractive index film of the above-described embodiment on the touch panel is not particularly limited, and may be implemented by a known method. For example, the structure etc. which patterned the ITO electrode on the coating-film surface of the film with a low refractive index film | membrane of the above-mentioned embodiment, and laminated | stacked the alignment film and the liquid crystal layer etc. are mentioned.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to a following example.

[Example 1]
"Production of siloxane bond-forming substances"
25 parts by mass of tetraethoxysilane, 1.5 parts by mass of nitric acid, 1.5 parts by mass of water, and 72 parts by mass of isopropyl alcohol are mixed and stirred at room temperature for 6 hours to obtain the siloxane bond of Example 1 A forming material (silica sol) was obtained.

"Preparation of a composition for forming a low refractive index film"
10 parts by mass of the resulting siloxane bond-forming substance, 1 part by mass of dipentaerythritol hexaacrylate, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} 2-methyl-propan-1-one 0.05 parts by mass, 1-butanol 29.65 parts by mass, propylene glycol monomethyl ether (PGM) 29.65 parts by mass, and butyl cellosolve 29.65 parts by mass By mixing, the composition for forming a low refractive index film of Example 1 was obtained.

"Production of plastic substrate with hard coat film"
30 parts by mass of dipentaerythritol hexaacrylate, 69 parts by mass of methyl isobutyl ketone, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl -Propan-1-one 1 mass part was mixed, and the composition for hard-coat film formation was obtained.

The obtained composition for forming a hard coat film was applied on a 100 μm-thick polyethylene terephthalate (PET) film by a bar coating method so as to have a dry film thickness of 1 to 2 μm, and dried by heating at 80 ° C. did.
Next, using a high pressure mercury lamp (120 W / cm), the coating film was exposed to ultraviolet rays so as to have an energy of 300 mJ / cm ² , and the coating film was cured to obtain a plastic substrate with a hard coat film.

"Formation of low refractive index film"
The composition for forming a low refractive index film of Example 1 was applied to the obtained plastic substrate with a hard coat film by a bar coating method so as to have a dry film thickness of 30 nm, and dried by heating at 80 ° C. did.
Next, using a high pressure mercury lamp (120 W / cm), the coating film was exposed to ultraviolet rays with an energy of 300 mJ / cm ² , and the coating film was cured to form a low refractive index film. An index film and a film with a low refractive index film provided with the index film were obtained.

[Example 2]
"Preparation of a composition for forming a low refractive index film"
16 parts by mass of the siloxane bond-forming substance of Example 1, 0.4 parts by mass of dipentaerythritol hexaacrylate, and 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl ] 0.02 parts by weight of phenyl} -2-methyl-propan-1-one, 27.86 parts by weight of 1-butanol, 27.86 parts by weight of propylene glycol monomethyl ether, and 27.86 parts by weight of butyl cellosolve. By mixing, the composition for forming a low refractive index film of Example 2 was obtained.

"Production of plastic substrate with hard coat film, formation of low refractive index film"
A low refractive index film was formed on a plastic substrate with a hard coat film in the same manner as in Example 1 except that the composition for forming a low refractive index film in Example 2 was used. A film and a film with a low refractive index film provided with the film were obtained.

[Example 3]
"Preparation of a composition for forming a low refractive index film"
4 parts by mass of the siloxane bond-forming substance of Example 1, 1.6 parts by mass of dipentaerythritol hexaacrylate, and 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl ] 0.08 parts by mass of phenyl} -2-methyl-propan-1-one, 31.44 parts by mass of 1-butanol, 31.44 parts by mass of propylene glycol monomethyl ether, and 31.44 parts by mass of butyl cellosolve. By mixing, the composition for forming a low refractive index film of Example 3 was obtained.

"Production of plastic substrate with hard coat film, formation of low refractive index film"
A low refractive index film was formed on a plastic substrate with a hard coat film in the same manner as in Example 1 except that the composition for forming a low refractive index film of Example 3 was used. A film and a film with a low refractive index film provided with the film were obtained.

[Example 4]
"Production of siloxane bond-forming substances"
20 parts by mass of tetraethoxysilane, 3 parts by mass of 3-methacryloxypropyltrimethoxysilane, 1.5 parts by mass of nitric acid, 1.5 parts by mass of water, and 74 parts by mass of isopropyl alcohol are mixed and brought to room temperature. The mixture was stirred for 6 hours to obtain the siloxane bond-forming substance (silica sol) of Example 4.

"Preparation of a composition for forming a low refractive index film"
A composition for forming a low refractive index film of Example 4 was obtained in the same manner as in Example 1, except that the siloxane bond-forming substance of Example 4 was used.

"Production of plastic substrate with hard coat film, formation of low refractive index film"
A low refractive index film was formed on a plastic substrate with a hard coat film in the same manner as in Example 1 except that the composition for forming a low refractive index film of Example 4 was used. A film and a film with a low refractive index film provided with the film were obtained.

[Example 5]
"Preparation of a composition for forming a low refractive index film"
16 parts by mass of the siloxane bond-forming substance of Example 4, 0.4 parts by mass of dipentaerythritol hexaacrylate, and 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl ] 0.02 parts by weight of phenyl} -2-methyl-propan-1-one, 27.86 parts by weight of 1-butanol, 27.86 parts by weight of propylene glycol monomethyl ether, and 27.86 parts by weight of butyl cellosolve. By mixing, the composition for forming a low refractive index film of Example 5 was obtained.

"Production of plastic substrate with hard coat film, formation of low refractive index film"
A low refractive index film is formed on a plastic substrate with a hard coat film in the same manner as in Example 1 except that the composition for forming a low refractive index film of Example 5 is used. A film and a film with a low refractive index film provided with the film were obtained.

[Example 6]
"Preparation of a composition for forming a low refractive index film"
4 parts by mass of the siloxane bond-forming substance of Example 4, 1.6 parts by mass of dipentaerythritol hexaacrylate, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl ] 0.08 parts by mass of phenyl} -2-methyl-propan-1-one, 31.44 parts by mass of 1-butanol, 31.44 parts by mass of propylene glycol monomethyl ether, and 31.44 parts by mass of butyl cellosolve. By mixing, the composition for forming a low refractive index film of Example 6 was obtained.

"Production of plastic substrate with hard coat film, formation of low refractive index film"
A low refractive index film is formed on a plastic substrate with a hard coat film in the same manner as in Example 1 except that the composition for forming a low refractive index film of Example 6 is used. A film and a film with a low refractive index film provided with the film were obtained.

[Example 7]
"Production of siloxane bond-forming substances"
20 parts by mass of tetraethoxysilane, 3 parts by mass of 3-glycidoxypropyltrimethoxysilane, 1.5 parts by mass of nitric acid, 1.5 parts by mass of water, and 74 parts by mass of isopropyl alcohol are mixed at room temperature. The mixture was stirred for 6 hours to obtain the siloxane bond-forming substance (silica sol) of Example 7.

"Preparation of a composition for forming a low refractive index film"
A composition for forming a low refractive index film of Example 7 was obtained in the same manner as in Example 1 except that the siloxane bond-forming substance of Example 7 was used.

"Production of plastic substrate with hard coat film, formation of low refractive index film"
A low refractive index film was formed on a plastic substrate with a hard coat film in the same manner as in Example 1 except that the composition for forming a low refractive index film of Example 7 was used. A film and a film with a low refractive index film provided with the film were obtained.

[Example 8]
"Preparation of a composition for forming a low refractive index film"
20 parts by mass of the siloxane bond-forming substance of Example 4, 26.67 parts by mass of 1-butanol, 26.67 parts by mass of propylene glycol monomethyl ether, and 26.66 parts by mass of butyl cellosolve were mixed. A composition for forming a low refractive index film was obtained.

"Production of plastic substrate with hard coat film, formation of low refractive index film"
A low refractive index film is formed on a plastic substrate with a hard coat film in the same manner as in Example 1 except that the composition for forming a low refractive index film of Example 8 is used. A film and a film with a low refractive index film provided with the film were obtained.

[Example 9]
"Production of siloxane bond-forming substances"
4 parts by mass of 3-methacryloxypropyltrimethoxysilane, 0.5 parts by mass of nitric acid, 0.5 parts by mass of water and 72 parts by mass of isopropyl alcohol were mixed and stirred at room temperature for 6 hours. The siloxane bond-forming substance (silica sol) of Example 9 was obtained.

"Preparation of a composition for forming a low refractive index film"
5 parts by mass of the resulting siloxane bond-forming substance, 1 part by mass of dipentaerythritol hexaacrylate, and mesoporous silica fine particles (trade name: SI-01, primary particle diameter of 5 nm to 15 nm, manufactured by Sumitomo Osaka Cement Co., Ltd.) are used as a homogenizer. 2.5 parts by mass of a dispersion (solid content 20% by mass) dispersed in isopropyl alcohol and 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} 2-methyl-2-propan-1-one 0.05 parts by mass, 1-butanol 30.48 parts by mass, propylene glycol monomethyl ether (PGM) 30.48 parts by mass, and butyl cellosolve 30.48 parts by mass. By mixing, the composition for forming a low refractive index film of Example 9 was obtained.

"Production of plastic substrate with hard coat film, formation of low refractive index film"
A low refractive index film was formed on a plastic substrate with a hard coat film in the same manner as in Example 1 except that the composition for forming a low refractive index film of Example 9 was used. A film and a film with a low refractive index film provided with the film were obtained.

[Comparative Example 1]
"Preparation of a composition for forming a low refractive index film"
Comparative Example 19.9 parts by weight of the siloxane bond-forming substance of Example 1, 26.7 parts by weight of 1-butanol, 26.7 parts by weight of propylene glycol monomethyl ether, and 26.7 parts by weight of butyl cellosolve were mixed. 1, a composition for forming a low refractive index film was obtained.

"Production of plastic substrate with hard coat film, formation of low refractive index film"
A low refractive index film was formed on a plastic substrate with a hard coat film in the same manner as in Example 1 except that the composition for forming a low refractive index film of Comparative Example 1 was used. A film and a film with a low refractive index film provided with the film were obtained.

[Comparative Example 2]
"Preparation of a composition for forming a low refractive index film"
2 parts by mass of dipentaerythritol hexaacrylate and 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one 1 part by mass, 32.64 parts by mass of 1-butanol, 32.63 parts by mass of propylene glycol monomethyl ether, and 32.63 parts by mass of butyl cellosolve are mixed, and the composition for forming a low refractive index film of Comparative Example 2 Got.

"Production of plastic substrate with hard coat film, formation of low refractive index film"
A low refractive index film was formed on a plastic substrate with a hard coat film in the same manner as in Example 1 except that the composition for forming a low refractive index film of Comparative Example 2 was used. A film and a film with a low refractive index film provided with the film were obtained.

[Comparative Example 3]
"Preparation of a composition for forming a low refractive index film"
20 parts by mass of the siloxane bond-forming substance of Example 7, 26.66 parts by mass of 1-butanol, 26.67 parts by mass of propylene glycol monomethyl ether, and 26.67 parts by mass of butyl cellosolve were mixed. A composition for forming a low refractive index film was obtained.

"Production of plastic substrate with hard coat film, formation of low refractive index film"
A low refractive index film was formed on a plastic substrate with a hard coat film in the same manner as in Example 1 except that the composition for forming a low refractive index film of Comparative Example 3 was used. A film and a film with a low refractive index film provided with the film were obtained.

[Comparative Example 4]
"Preparation of a composition for forming a low refractive index film"
15 parts by mass of the siloxane bond-forming substance prepared in Example 1, 2.5 parts by mass of a hollow silica IPA dispersion (primary particle size 100 nm to 120 nm, solid content 20% by mass), 27.5 parts by mass of 1-butanol Then, 27.5 parts by mass of propylene glycol monomethyl ether and 27.5 parts by mass of butyl cellosolve were mixed to obtain a composition for forming a low refractive index film of Comparative Example 4.

"Production of plastic substrate with hard coat film, formation of low refractive index film"
A low refractive index film was formed on a plastic substrate with a hard coat film in the same manner as in Example 1 except that the composition for forming a low refractive index film of Comparative Example 4 was used. A film and a film with a low refractive index film provided with the film were obtained.

  About the film with a low refractive index film obtained in Examples 1 to 9 and Comparative Examples 1 to 4, the dynamic friction coefficient, anti-blocking property, haze value, scratch resistance, adhesion, refractive index, and arithmetic average roughness Ra, Evaluation was made by the following method. The evaluation results are shown in Tables 1 and 2.

(1) Dynamic friction coefficient The dynamic friction coefficient was measured based on Japanese Industrial Standard JIS-K-7125.
The case where the dynamic friction coefficient was less than 0.5 was evaluated as “◎”, the case where 0.5 or more and less than 0.6 was evaluated as “◯”, and the case where 0.6 or more was evaluated as “×”.

(2) Anti-blocking property The low refractive index films of the film with a low refractive index film were rubbed together to perform sensory evaluation. When the films with low refractive index films were rubbed together, the slippery film was evaluated as “◯”, and the non-slipable film was evaluated as “x”.

(3) Haze value The haze value of a film with a low refractive index film was measured based on Japanese Industrial Standards JIS-K-7136 using a haze meter NDH-2000 (manufactured by Nippon Denshoku) with air as a reference.
For the measurement of the haze value, a test piece of 100 mm × 100 mm was produced from the produced film with a low refractive index film, and the test piece was used.
The evaluation result of A is a non-defective product, and as the evaluation result changes from B to D, the transparency is deteriorated.
A: Less than 1.0% B: 1.0% or more and less than 1.5% C: 1.5% or more and 2.0% or less D: Greater than 2.0%

(4) Scratch resistance On a low refractive index film of a film with a low refractive index film, # 0000 steel wool was slid 10 times under a load of 250 g / cm ² . The surface of the hard coat film after reciprocation was visually observed, and the scratch resistance was evaluated according to the following criteria.
The evaluation result of A is a non-defective product, and as the evaluation result changes from B to E, the hard coat property is low.
A: 0 scratches B: 1-10 scratches C: 11-20 scratches D: 20-30 scratches E: 31 or more scratches

(5) Adhesion Adherence based on Japanese Industrial Standards: JIS-K-5600-5-6 "General coating test methods-Part 5: Mechanical properties of coating films-Section 6: Adhesion (cross-cut method)" Sexuality was evaluated. Here, “◎” indicates a JIS evaluation result classification 0, “◯” indicates a JIS evaluation result classification 1, “△” indicates a JIS evaluation result classification 2, and JIS evaluation result classification 3-5. Some were marked as “x”.

(6) Refractive index The refractive index of the low refractive index film | membrane of the film with a low refractive index film | membrane was measured using the prism coupler model 2010 (made by Merikon).

(7) Arithmetic mean roughness Ra
The range of 20 μm × 20 μm was scanned with an atomic force microscope (AFM) (trade name: SPA300 / SPI3700, manufactured by SII), the arithmetic average roughness Ra was calculated, and the surface roughness was measured according to the following criteria. Evaluation was performed.
×: Arithmetic average roughness Ra is 3 nm or more Δ: Arithmetic average roughness Ra is 2 nm or more and less than 3 nm ○: Arithmetic average roughness Ra is less than 2 nm

From the results in Table 1 and Table 2, when Examples 1 to 9 and Comparative Examples 1 to 4 are compared, the films with a low refractive index film of Examples 1 to 9 are anti-blocking, transparent, and scratch resistant. It was confirmed that the low refractive index film was excellent in adhesion and arithmetic average roughness Ra.
From the results of Table 1 and Table 2, when Examples 1 to 3 and Comparative Example 1 are compared, the low refractive index film-attached films of Examples 1 to 3 have improved adhesion of the low refractive index film. I was able to confirm.
From the results of Table 1 and Table 2, when Examples 1 to 9 and Comparative Example 2 are compared, it can be confirmed that the anti-blocking properties of the films with low refractive index films of Examples 1 to 9 are improved. It was.
From the results of Table 1 and Table 2, when Examples 4 to 6 and Comparative Example 3 are compared, the films with low refractive index films of Examples 4 to 6 are anti-blocking, scratch resistant, and low refractive index films. It was confirmed that the adhesion was improved.
From the results of Tables 1 and 2, when Example 7 and Comparative Example 4 are compared, the film with a low refractive index film of Example 7 has anti-blocking properties, scratch resistance, and adhesion of the low refractive index film. It was confirmed that there was an improvement.

About the film with a low refractive index film obtained in Examples 1 to 9, a 20 μm × 20 μm range was scanned with an atomic force microscope (AFM) (trade name: SPA300 / SPI3700, manufactured by SII). Peak-to-valley value (PV value) was calculated.
As a result of scanning by AFM, the low refractive index film containing no particles such as mesoporous silica of Examples 1 to 8 showed no noticeable irregularities over the entire surface of 20 μm × 20 μm, and a uniform film was obtained. On the other hand, in the low refractive index film of Example 9 containing mesoporous silica particles, unevenness was observed over the entire film surface.
Moreover, the PV value of Examples 1-8 was 30 nm or less, and the PV value of Example 9 was 76.4 nm. The PV value of Example 8 was 11.5 nm.
From this result, it was confirmed that the film surface of the low refractive index film of this example in which inorganic fine particles were not mixed was uniform.

  Since the composition for forming a low refractive index film of the present invention contains silicon alkoxide and a crosslinkable compound having at least one methacryloyl group and acryloyl group in the molecule, anti-blocking properties It is possible to form an excellent low refractive index film, and the low refractive index film can be applied to a touch panel or the like.

Claims (6)

  A composition for forming a low refractive index film, comprising a silicon alkoxide and a crosslinkable compound having at least one methacryloyl group and acryloyl group in a molecule.   It contains a compound having a siloxane bond and an acrylic resin, has a refractive index of 1.37 or more and 1.51 or less, and has a dynamic friction coefficient and a static friction coefficient of 0.6 or less when the film surfaces are brought into contact with each other. A low refractive index film having a surface arithmetic average roughness Ra of 3 nm or less. A film with a low refractive index film in which a hard coat film and a low refractive index film are provided in order from one main surface of the base film,
The low refractive index film is the low refractive index film according to claim 2,
A film with a low refractive index film, wherein the arithmetic average roughness Ra of the surface of the low refractive index film is 3 nm or less.   The low refractive index film according to claim 3, further comprising a high refractive index film having a refractive index of 1.51 or more and 1.85 or less between the hard coat film and the low refractive index film. the film. A film with a low refractive index film in which a high refractive index hard coat film having a refractive index of 1.51 or more and 1.85 or less and a low refractive index film are provided in order from one main surface of the base film. And
The low refractive index film is the low refractive index film according to claim 2,
The absolute value of the refractive index difference between the base film and the high refractive index hard coat film is 0 or more and 0.48 or less,
A film with a low refractive index film, wherein the arithmetic average roughness Ra of the surface of the low refractive index film is 3 nm or less.   A touch panel comprising at least one of the low refractive index film according to claim 2 and the film with a low refractive index film according to any one of claims 3 to 5.