JP5509774B2 - Curable resin composition for antifouling surface layer and optical film - Google Patents

Description

  The present invention relates to an optical film installed on the front surface of a display (image display device) such as a liquid crystal display (LCD), a cathode ray tube display (CRT), a plasma display (PDP), or an organic electroluminescence (organic EL), and a surface thereof. It relates to a composition for the layer.

In the display as described above, for example, an image display surface of a display such as a television, a personal computer, a mobile phone, a GPS (Global Positioning System), a car navigation, a pen tablet, a CAD (Computer Aided Design), a small game machine, and a portable audio. It is required to give hardness so as not to be damaged during handling. On the other hand, it is a common practice to impart hardness to the image display surface of a display by using an optical film in which a hard coat layer is provided on a base film.
Further, the display as described above is generally imparted with antifouling properties so that dirt such as fingerprints and magic ink adheres during handling and the visibility of the image display surface does not deteriorate. In Patent Document 1, a curable composition for forming a cured film for imparting chemical resistance and antifouling property and reducing the reflectance, and an antireflection film or a hard coat layer comprising the cured film are disclosed. An antireflection film having the antireflection film is disclosed directly.

  Although the fluorine-containing surface modifier (reactive fluorine compound) listed in [0132] of Patent Document 1 is excellent in antifouling properties, it is difficult to become familiar with a binder component for forming a cured film, and phase separation is prevented. As a result, repelling (dents and holes in the coating surface) and bubbles are likely to occur on the coating surface when the composition is applied, and a beautiful coating surface cannot be formed, resulting in a poor appearance.

  Moreover, this cured coating film (antireflection film) of Patent Document 1 requires hollow silica fine particles in order to reduce the refractive index. Hollow silica fine particles have a porous structure and pores inside the particles and contain air with a refractive index as low as 1 and contribute to lowering the refractive index. However, the hardness of the cured film is reduced by the porous structure and pores. There was a problem of shortage.

  Thus, there is a demand for an optical film that is further excellent in antifouling properties, hardness, and coating surface conditions.

JP 2008-040262 A

  The present invention has been made to solve the above-mentioned problems, and is a curable resin composition for an antifouling surface layer capable of forming an antifouling surface layer excellent in antifouling properties, hardness and coating surface state. And it aims at providing the optical film provided with the antifouling surface layer which consists of the hardened | cured material.

  As a result of intensive studies by the present inventors, a reactive fluorine compound was used in combination with pentaerythritol triacrylate (hereinafter sometimes referred to as PETA) or urethane acrylate composed of a reaction product of PETA and isocyanate in a specific ratio. If it is a composition, it discovered that it was excellent in antifouling property and hardness, and the state of the coating surface was good and the external appearance was favorable, and came to complete this invention.

That is, the curable resin composition for an antifouling surface layer according to the present invention that solves the above problems is (A) urethane acrylate comprising pentaerythritol triacrylate and / or a reaction product of pentaerythritol triacrylate and isocyanate, binder system comprising, (B) a reactive fluorine compound represented by the following general formula (1), and includes a reactive silica fine particles having a crosslinking reactivity with the component (a) and (B) component, the (a ) Component in an amount of 60% by mass or more based on the total mass of the binder system, and the component (B) is 0.005 based on the total mass of the total solid content of the curable resin composition for an antifouling surface layer. It is characterized by containing -3 mass%.

（一般式（１）において、ｎは１〜５の整数である。）

(In general formula (1), n is an integer of 1-5.)

  In the composition, when the component (A) and the component (B) are contained in the specific content, the anti-fouling surface layer curable resin composition according to the present invention has excellent anti-resistance when cured. While exhibiting dirtiness and hardness, defects such as repellency and bubbles on the surface of the cured film are suppressed, and the coated surface is in good condition and has an excellent appearance.

  The optical film according to the present invention is an optical film having an antifouling surface layer on the outermost surface of one side of the light transmissive substrate, and the antifouling surface layer is curable for the antifouling surface layer. It consists of the hardened | cured material of a resin composition, It is characterized by the above-mentioned.

  An optical film according to the present invention having an outermost surface layer composed of a cured product of a composition containing a specific binder component such as PETA and a specific reactive fluorine compound represented by the general formula (1) in a specific content ratio, While having excellent antifouling properties and hardness, it suppresses defects such as repellency and bubbles on the surface of the outermost surface layer, and has an effect that the state of the coated surface is good and the appearance is excellent. Moreover, the curable resin composition for antifouling surface layers according to the present invention can provide such a composition.

FIG. 1 is a schematic view showing an example of a layer structure of an optical film according to the present invention. FIG. 2 is a schematic view showing another example of the layer structure of the optical film according to the present invention. FIG. 3 is a schematic view showing another example of the layer structure of the optical film according to the present invention. FIG. 4 is a schematic view showing another example of the layer structure of the optical film according to the present invention.

  Hereinafter, the curable resin composition for an antifouling surface layer according to the present invention, an optical film, and a method for producing the optical film will be described.

In the present invention, (meth) acrylate represents acrylate and / or methacrylate.
The light of the present invention includes not only electromagnetic waves having wavelengths in the visible and non-visible regions, but also particle beams such as electron beams, and radiation or ionizing radiation that collectively refers to electromagnetic waves and particle beams.
In the present invention, the “hard coat layer” refers to a layer having a hardness of “H” or higher in a pencil hardness test (4.9 N load) defined in JIS K5600-5-4 (1999).
In the definition of film and sheet in JIS-K6900, a sheet is a thin and generally flat product whose thickness is small relative to the length and width. A film has a thickness compared to the length and width. A thin, flat product that is extremely small and has an arbitrarily limited maximum thickness, usually supplied in the form of a roll. Accordingly, it can be said that a sheet having a particularly thin thickness is a film, but the boundary between the sheet and the film is not clear and is difficult to distinguish clearly. Therefore, in the present invention, both a thick sheet and a thin sheet are used. Including meaning, it is defined as “film”.
In the present invention, the resin is a concept including a polymer in addition to a monomer and an oligomer, and means a component that becomes a matrix of the HC layer and other functional layers after curing.
In the present invention, the molecular weight means a weight average molecular weight which is a polystyrene equivalent value measured by gel permeation chromatography (GPC) in a THF solvent when having a molecular weight distribution, and when having no molecular weight distribution, It means the molecular weight of the compound itself.
In the present invention, the average particle size of the fine particles means a value measured using a Microtrac particle size analyzer manufactured by Nikkiso Co., Ltd. in the case of fine particles in the composition. It means the average value of 10 particles observed by a transmission electron microscope (TEM) photograph of the cross section of the membrane.
The contact angle in the present invention is a microscope contact angle meter CA-QI series manufactured by Kyowa Interface Science Co., Ltd. at 25 ° C. in accordance with JIS R 3257 (1999) “Test method for wettability of substrate glass surface”. It is the value measured using.

(Curable resin composition for antifouling surface layer)
A curable resin composition for an antifouling surface layer according to the present invention includes (A) a binder system containing (A) pentaerythritol triacrylate and / or urethane acrylate composed of a reaction product of pentaerythritol triacrylate and isocyanate, and (B). The reactive fluorine compound represented by the following general formula (1) is included, the component (A) is included in an amount of 60% by mass or more based on the total mass of the binder system, and the component (B) is an antifouling surface layer. It is characterized by including 0.005-3 mass% with respect to the total mass of the total solid of the curable resin composition.

（一般式（１）において、ｎは１〜５の整数である。）

(In general formula (1), n is an integer of 1-5.)

  In the curable resin composition for an antifouling surface layer (hereinafter sometimes simply referred to as an antifouling composition), the component (A) and the component (B) are included at the specific content. The curable resin composition for an antifouling surface layer according to the present invention suppresses defects such as repellency and foam on the surface of the cured film while exhibiting excellent antifouling properties and hardness when cured, and is applied to the coating. The surface condition is good and the appearance is excellent.

  Hereinafter, the binder system containing the component (A), which is an essential component of the curable resin composition for an antifouling surface layer according to the present invention, the component (B), and other components that may be appropriately included as necessary. The components will be described.

(Binder system)
The binder system is a system that is cured to become a matrix of a cured film.
A binder system contains 60 mass% or more of (A) components, such as PETA mentioned later at least with respect to the total mass of the said binder system. The binder system may contain other binder components.

(A: urethane acrylate comprising a reaction product of pentaerythritol triacrylate and / or pentaerythritol triacrylate and isocyanate)
In the antifouling composition, (A) component PETA or urethane acrylate composed of a reaction product of pentaerythritol triacrylate and isocyanate (hereinafter sometimes simply referred to as PETA-derived urethane acrylate) is based on the total mass of the binder system. When the antifouling composition is cured, it has a function of suppressing defects such as repellency and bubbles on the surface of the cured film while imparting excellent hardness to the cured film. . The reason for this is not clear, but it is presumed that PETA and PETA-derived urethane acrylate have high affinity with the reactive fluorine compound described later and do not phase separate from the reactive fluorine compound.

  The content ratio of the component (A) with respect to the total mass of the binder system may be 60% by mass or more, and preferably 70% by mass.

As an isocyanate used as a raw material of the PETA-derived urethane acrylate, any isocyanate having an isocyanate group (—NCO) may be used. The isocyanate preferably has 1 to 10 isocyanate groups per molecule, and more preferably 2 to 5 isocyanate groups.
The basic structure of isocyanate includes chain saturated hydrocarbons, chain unsaturated hydrocarbons, cyclic saturated hydrocarbons and cyclic unsaturated hydrocarbons and those containing heteroatoms, and substituents such as carbonyl gas. And combinations thereof.
As the isocyanate of the present invention, isophorone diisocyanate (CAS registration number 4098-71-9) represented by the following general formula (2), hexamethylene diisocyanate (CAS registration number 822-06-0) represented by the following general formula (3) ), A compound represented by the following general formula (4) (CAS registration number 3779-63-3) and 1,3-cyclohexanediyl bismethylene diisocyanate (CAS registration number 38661-72-2) represented by the following general formula (5) ) Is preferable from the viewpoint of transparency, hardness, viscosity, coated surface quality, and discoloration suppression after a durability test.

PETA-derived urethane acrylate is a reaction product of PETA and the above isocyanate, and is formed by condensation of the hydroxyl group of PETA and the isocyanate group of isocyanate.
The PETA-derived urethane acrylate may be one in which an isocyanate having two or more isocyanate groups in one molecule reacts with two or more PETAs by the isocyanate groups.
The acryloyl group contained in one molecule of the PETA-derived urethane acrylate may be appropriately adjusted according to the desired properties, but is preferably 3 to 15 and more preferably 3 to 9 from the viewpoint of increasing the hardness of the cured film.

  The molecular weight of one PETA-derived urethane acrylate molecule may be appropriately adjusted according to the desired properties, preferably 1000 to 20000, and more preferably 1000 to 10,000.

  Commercially available products of PETA-derived urethane acrylate include, for example, trade name BS577 manufactured by Arakawa Chemical Industries, Ltd. (reactant of isophorone diisocyanate represented by the above general formula (2) as alcohol, PETA as alcohol, molecular weight 1000, hexafunctional ), Trade name H120 manufactured by Negami Kogyo Co., Ltd. (PETA as alcohol, 1,3-cyclohexanediyl bismethylene diisocyanate represented by the above general formula (5) as isocyanate (hexahydrometaxylylene diisocyanate or hydrogenated xylylene diisocyanate) And a product name HDPIPD (reactant of isophorone diisocyanate represented by the above general formula (2) as an isocyanate, molecular weight 3000, hexafunctional). Nippon Gosei the beauty (trade name) manufactured by UV7640B (PETA as an alcohol, a reaction product of isophorone diisocyanate represented by the above general formula as an isocyanate (2), the molecular weight 1500,6 functional), and the like.

(Other binder components)
The binder system may contain other binder components other than the component (A) without departing from the gist of the present invention. Examples of the other binder component include a binder component having a photocurable group such as an ionizing radiation curable unsaturated group, which is used in a conventionally known HC layer or the like. For example, a polyalkylene oxide chain-containing polymer and dipentaerythritol hexa (meth) acrylate and 1,6-hexanediol di (meth) acrylate, isocyanuric acid EO-modified triacrylate, isocyanuric acid EO described in JP2008-165040A Bifunctional or higher functional compounds such as modified diacrylate, trimethylolpropane triacrylate, polyester triacrylate, pentaerythritol tetraacrylate, etc., and (meth) acrylate oligomers, and compounds having a molecular weight of less than 10,000 are listed. It is done.

(B: Reactive fluorine compound)
The reactive fluorine compound of the present invention is a compound represented by the following general formula (1).

（一般式（１）において、ｎは１〜５の整数である。）

(In general formula (1), n is an integer of 1-5.)

  The component (B) is contained in an amount of 0.005 to 3% by mass with respect to the total mass of the total solid content of the antifouling composition, preferably 0.01 to 2% by mass, and 0.05 to 1% by mass. More preferred. When the content ratio of the component (B) is 0.005% by mass or more, sufficient antifouling properties are exhibited. When the content ratio of the component (B) exceeds 3% by mass, the compatibility with the binder component such as the component (A) contained in the binder system is lowered, and defects such as repellency and bubbles on the surface of the cured film are likely to occur. And the coating surface condition deteriorates.

  The compound represented by the general formula (1) is a method described in Patent Document 1 using a compound represented by the above general formula (4), a compound represented by the following general formula (6), and 2-hydroxyethyl acrylate. It is obtained by.

（一般式（６）において、ｎは１〜５の整数である。）

(In general formula (6), n is an integer of 1-5.)

  In addition, as a commercial product of the compound represented by the general formula (1), trade name OPTOOL DAC manufactured by Daikin Industries, Ltd. is also available.

  In addition to the components (A) and (B), the antifouling composition may contain a solvent, reactive silica fine particles, a polymerization initiator, an antistatic agent, and the like as necessary. Hereinafter, other components that may be contained in the antifouling composition will be described.

(solvent)
As the solvent, cellosolve solvents, ester solvents, propylene glycol solvents, ketone solvents, alcohol solvents and aromatic hydrocarbons described in Patent Document 1 can be used.
In addition, methyl ethyl ketone and propylene glycol monomethyl ether can also be preferably used.
In the antifouling composition of the present invention, as a solvent, it is possible to contain a solvent selected from the group consisting of (C) methyl ethyl ketone and propylene glycol monomethyl ether in terms of solubility or dispersibility of the components (A) and (B). It is preferable because it is particularly excellent.
When using a solvent for the antifouling composition of the present invention, the solvent (C) is preferably contained in an amount of 50 to 100% by mass, more preferably 70 to 100% by mass, based on the total mass of the solvent. preferable.
The said solvent may be used individually by 1 type, and may mix and use 2 or more types.

(Reactive silica fine particles)
The antifouling composition of the present invention may contain reactive silica fine particles for the purpose of improving the hardness of the cured film. The reactive silica fine particles are excellent in hardness and have a photocurable group such as an acryloyl group on the surface of the fine particles. Therefore, the reactive silica fine particles can be crosslinked with the binder component and the reactive fluorine compound contained in the binder system. Can be given hardness. When the antifouling composition of the present invention is used to form an antifouling hard coat layer, it is preferable that reactive silica fine particles are contained.
As the reactive silica fine particles, conventionally known fine particles may be used. For example, reactive silica fine particles described in JP-A-2008-165040 can be used.
The average particle diameter of the reactive silica fine particles is preferably 1 to 100 nm from the viewpoint of transparency (haze) of the cured film.
In addition, when the optical film of the present invention is saponified, the average particle diameter of the reactive silica fine particles is preferably 20 nm or more from the viewpoint of saponification resistance. By being in this range, when the optical film is immersed in an aqueous sodium hydroxide solution (saponification bath) and saponification is performed, the reactive silica fine particles are removed from the surface of the optical film and are removed. It is easy to suppress the falling off of the cured product of the reactive fluorine compound.
When reactive silica fine particles are used, the content thereof is preferably 1 to 60% by mass and more preferably 30 to 50% by mass with respect to the total mass of the total solid content of the antifouling composition. . By being in this range, the hardness of the antifouling surface layer can be improved while suppressing the haze increase, the decrease in adhesion to the light-transmitting substrate, and the deterioration of the coated surface due to the occurrence of repellency and the like.
Further, particles (reactive atypical silica fine particles) in which silica fine particles described in JP-A-2009-108123 are linked in a chain and surface-treated with a silane coupling agent can also be used.

(Polymerization initiator)
If necessary, radicals and cationic polymerization initiators may be appropriately selected and used. Examples of the radical polymerization initiator include Irgacure 184 (1-hydroxy-cyclohexyl-phenyl-ketone) manufactured by Ciba Japan Co., Ltd.
When using a polymerization initiator, it is preferable that the content is 1-10 mass% with respect to the total mass of the total solid of an antifouling composition.

(Antistatic agent)
As the antistatic agent, conventionally known antistatic agents can be used. For example, cationic antistatic agents such as quaternary ammonium salts, fine particles such as tin-doped indium oxide (ITO), and organic conductive materials such as polythiophene. Can be used.
When using an antistatic agent, it is preferable that the content is 1-30 mass% with respect to the total mass of the total solid of an antifouling composition.

(Anti-glare agent)
Conventional anti-glare agents such as fine particles such as styrene beads (refractive index 1.59) may be used as the anti-glare agent. When using a particulate antiglare agent, the content is preferably 2 to 30% by mass with respect to the total mass of the total solid content of the antifouling composition.

(Antimicrobial agent)
As the antibacterial agent, commercially available industrial antibacterial agents can be used. Industrial antibacterial agents include organic antibacterial agents and inorganic antibacterial agents, either of which may be used.

  Examples of inorganic antibacterial agents include NOVALON AG330, AG020, AG300, and AG1100 manufactured by Toagosei Co., Ltd.

  Examples of the organic antibacterial agent include NK Economer ADP-51, ADP-33, AL, AL-4G, AL-8G, AL-12G, ML, ML-4G, ML- manufactured by Shin-Nakamura Chemical Co., Ltd. Examples thereof include 8G and ML-12G, BZBEHS (X8129), BZBEHP (X8128), AL00GT and the like manufactured by Nikka Chemical Co., Ltd.

  When using an antibacterial agent, it is preferable that the content is 0.001-10 mass% with respect to the total mass of the total solid of an antifouling composition.

(Optical film)
The optical film according to the present invention is an optical film having an antifouling surface layer on the outermost surface of one side of the light transmissive substrate, and the antifouling surface layer is curable for the antifouling surface layer. It consists of the hardened | cured material of a resin composition, It is characterized by the above-mentioned.

FIG. 1 is a schematic view showing an example of a layer structure of an optical film according to the present invention.
An antifouling surface layer 20 made of a cured product of the curable resin composition for an antifouling surface layer is provided on one surface side of the light transmissive substrate 10.

FIG. 2 is a schematic view showing another example of the layer structure of the optical film according to the present invention.
An antifouling hard coat layer 21 made of a cured product of a curable resin composition for an antifouling surface layer containing reactive silica fine particles is provided on one surface side of the light transmissive substrate 10.

FIG. 3 is a schematic view showing another example of the layer structure of the optical film according to the present invention.
An antistatic layer 40 and an antifouling hard coat layer 21 are provided on one side of the light transmissive substrate 10 from the light transmissive substrate 10 side.

FIG. 4 is a schematic view showing another example of the layer structure of the optical film according to the present invention.
An antifouling layer comprising a cured product of the curable resin composition for the antistatic layer 40, the low refractive index layer 50, and the antifouling surface layer, on the one surface side of the light transmissive substrate 10 from the light transmissive substrate 10 side. 22 is provided.

  Hereinafter, a light-transmitting substrate and an antifouling surface layer, which are essential components of the optical film according to the present invention, and a hard coat layer, a high refractive index layer, and a medium refractive index layer that can be provided as necessary. The antiglare layer and the antistatic layer will be described.

(Light transmissive substrate)
The light-transmitting substrate of the present invention is not particularly limited as long as it satisfies the physical properties that can be used as the light-transmitting substrate of the optical laminate, and is used for conventionally known hard coat films and optical films. TAC, polyethylene terephthalate (PET), cycloolefin polymer, or the like can be appropriately selected and used.
The average light transmittance of the light-transmitting substrate in the visible light region of 380 to 780 nm is preferably 50% or more, more preferably 70% or more, and particularly preferably 85% or more. The light transmittance is measured using a value measured in the air at room temperature using an ultraviolet-visible spectrophotometer (for example, UV-3100PC manufactured by Shimadzu Corporation).
Further, the light-transmitting substrate may be subjected to a surface treatment such as a saponification treatment or a primer layer. In addition, additives such as an antistatic agent may be added.
The thickness of the light-transmitting substrate is not particularly limited, and is usually about 30 to 200 μm, preferably 40 to 200 μm.

(Anti-fouling surface layer)
The antifouling surface layer of the present invention is a layer provided on the outermost surface on one side of the light transmissive substrate, that is, the side opposite to the light transmissive substrate of the optical film of the present invention.
The antifouling surface layer is composed of a cured product of the curable resin composition for the antifouling surface layer, and thus has excellent antifouling properties and hardness while suppressing defects such as repellency and bubbles on the surface. The coated surface is good and the appearance is excellent.

The antifouling surface layer of the present invention may be provided directly on one side of the light transmissive substrate as shown in FIG. 1, or an antistatic layer or a high layer described later on one side of the light transmissive substrate. It may be provided via other layers such as a refractive index layer.
The thickness of the antifouling surface layer may be appropriately adjusted according to desired properties, and may be, for example, 100 nm to 20 μm.

When the curable resin composition for an antifouling surface layer contains reactive silica fine particles, the cured film is excellent in hardness, so that the antifouling surface layer is hard as shown in FIGS. It can also be suitably used as a coat layer.
When used as an antifouling hard coat layer, the thickness may be appropriately adjusted according to desired properties, and may be, for example, 1 to 20 μm.

When the curable resin composition for an antifouling surface layer is excellent in antifouling properties, the antifouling surface layer can be suitably used as an antifouling layer as shown in FIG.
When used as an antifouling layer, the thickness may be adjusted as appropriate according to the desired properties, for example, 50 to 500 nm.

A contact angle with respect to a liquid such as water or hexadecane is used as an index for evaluating antifouling properties such as fingerprint wiping property of an optical film. In general, the greater the contact angle to such a liquid, the higher the antifouling property.
In the optical film according to the present invention, the contact angle of the antifouling surface layer with respect to water and hexadecane is 102 ° or more and 50 ° or more, respectively, from the viewpoint of improving the antifouling property of the antifouling surface layer, particularly the fingerprint wiping property. It is preferable that
In addition, when the light-transmitting substrate is a triacetylcellulose substrate, the contact angle with respect to water and hexadecane after the saponification treatment of the antifouling surface layer is increased from the point of improving the antifouling property and saponification resistance, It is preferably 92 ° or more and 45 ° or more. Even after the saponification treatment, the large contact angle to the liquid indicates that the antifouling property is high.
Here, the saponification treatment refers to immersing the optical film in a 2N sodium hydroxide aqueous solution at a temperature of 55 ° C. for 2 minutes.
In the optical film of the present invention, the surface tension of the curable resin composition for an antifouling surface layer is preferably 24 mN / m or less from the viewpoint of obtaining a good coated surface, and more preferably 22 mN / m or less.
The surface tension can be measured by a Wilhelmy method by preparing a composition in a methyl isobutyl ketone solution having a solid content of 50% using a dynamic wettability tester manufactured by Reska Co., Ltd.

(Hard coat layer)
The hard coat layer is a layer showing a hardness of “H” or higher in the pencil hardness test (4.9 N load) specified in JIS K5600-5-4 (1999), and the hardness of the optical film according to the present invention is determined. Has a function to enhance.
The hard coat layer may be a conventionally known hard coat layer, may be composed of a cured product of a composition containing only a binder component, or the reactive silica mentioned in the above antifouling composition. Fine particles, a polymerization initiator, and the like may be included in the composition.
As the binder component, a conventionally known binder component of a hard coat layer can be used. For example, those mentioned in the antifouling surface layer can be used.
What is necessary is just to adjust the film thickness of a hard-coat layer suitably, for example, what is necessary is just 1-20 micrometers.

(High refractive index layer and medium refractive index layer)
The high refractive index layer and the middle refractive index layer are layers provided for adjusting the reflectance of the optical film according to the present invention, and the high refractive index layer is disposed on the light-transmitting substrate side of the antifouling surface layer. The middle refractive index layer is a layer provided adjacent to the light transmissive substrate side of the high refractive index layer.
The high refractive index layer and the medium refractive index layer usually contain mainly a binder component and particles for adjusting the refractive index. As the binder component, those mentioned in the antifouling surface layer can be used.
Examples of the particles for adjusting the refractive index include fine particles having a particle diameter of 100 nm or less. Examples of such fine particles include zinc oxide (refractive index: 1.90), titania (refractive index: 2.3 to 2.7), ceria (refractive index: 1.95), and tin-doped indium oxide (refractive index: 1). .95), at least one selected from the group consisting of antimony-doped tin oxide (refractive index: 1.80), yttria (refractive index: 1.87), and zirconia (refractive index: 2.0). it can.
Specifically, the high refractive index layer preferably has a refractive index of 1.50 to 2.80.
The medium refractive index layer has a low refractive index for the high refractive index layer, and preferably has a refractive index of 1.50 to 2.00.

(Antistatic layer)
The antistatic layer is a layer having a function of suppressing the generation of static electricity to prevent the adhesion of dust or preventing external static electricity failure when incorporated in a liquid crystal display or the like.
The antistatic layer comprises a cured product of a composition containing an antistatic agent and a binder component. What is necessary is just to adjust the film thickness of an antistatic layer suitably, and it is preferable that they are 30 nm-3 micrometers.
As the performance of the antistatic layer, it is preferable that the surface resistance after forming the optical film is 10 ¹² Ω / □ or less. In addition, a surface resistance value can be measured using High Leister HT-210 made from Mitsubishi Yuka Co., Ltd.
As the antistatic agent, conventionally known ones can be used. For example, a cationic compound, an anionic compound, an amphoteric compound, a nonionic compound, an organometallic compound and a metal chelate compound described in JP-A-2008-165040 are used. be able to.
It is preferable that content of an antistatic agent is 1-30 mass% with respect to the total mass of the total solid of the composition for antistatic layers.
As the binder component that is cured to form the antistatic layer, a binder component of a conventionally known antistatic agent may be used, and those listed above for the antifouling surface layer may be used.

(Anti-glare layer)
The antiglare layer is composed of a cured product of a composition containing a binder component and an antiglare agent, and the binder component may be the same as that described for the antifouling surface layer.
Examples of the antiglare agent include fine particles, and examples thereof include styrene beads (refractive index 1.59), melamine beads (refractive index 1.57), and acrylic beads (refractive index 1.49). The average particle size of the fine particles is preferably 100 to 500 nm.
The content of the antiglare fine particles is preferably 2 to 30% by mass with respect to the total mass of the binder component.

(Low refractive index layer)
The low refractive index layer is composed of a cured product of a composition containing a low refractive index component such as silica or magnesium fluoride and a binder component or a composition containing a fluorine-containing resin such as a vinylidene fluoride copolymer. It can be a low refractive index layer.
The composition for forming the low refractive index layer may contain hollow particles in order to reduce the refractive index of the low refractive index layer.
A hollow particle refers to a particle having an outer shell layer and the inside surrounded by the outer shell layer being a porous structure or a cavity. The porous structure or cavity contains air (refractive index: 1), and the refractive index of the low refractive index layer is obtained by including hollow particles having a refractive index of 1.20 to 1.45 in the low refractive index layer. Can be reduced.
The average particle diameter of the hollow particles is preferably 1 to 100 nm.
As the hollow particles, those conventionally used for a low refractive index layer can be used, and examples thereof include fine particles having voids described in JP-A-2008-165040.

(Optical film manufacturing method)
The method for producing an optical film of the present invention comprises a step of applying the antifouling composition to the outermost surface on one side of a light transmissive substrate, and irradiating with light to cure to form an antifouling surface layer. Including.
The antifouling composition may be applied directly on the light transmissive substrate, or may be applied on other layers such as the antistatic layer as described above formed on the light transmissive substrate. good. Further, if the antifouling composition is the outermost surface, it may be applied simultaneously with the composition of other layers such as an antistatic layer.

  The antifouling composition is usually prepared by mixing and dispersing a polymerization initiator and the like in addition to the components (A) and (B) in a solvent according to a general preparation method. A paint shaker or a bead mill can be used for mixing and dispersing. When the component (A) has fluidity, the antifouling composition can be applied to the substrate without using a solvent, and therefore a solvent may be used as necessary.

  The coating method may be a conventionally known method, and is not particularly limited. Spin coating method, dip method, spray method, slide coating method, bar coating method, roll coater method, meniscus coater method, flexographic printing method, screen printing Various methods such as a method and a pea coater method can be used.

For light irradiation, ultraviolet rays, visible light, electron beams, ionizing radiation, etc. are mainly used. In the case of ultraviolet curing, ultraviolet rays emitted from light such as an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, and a metal halide lamp are used. The irradiation amount of the energy ray source is about 50 to 500 mJ / cm ² as an integrated exposure amount at an ultraviolet wavelength of 365 nm.
Light irradiation prevents oxygen inhibition on the antifouling composition surface, prevents wiping off the component (B) after curing of the antifouling composition, and prevents it from falling off due to saponification, as well as an oily component contained in magic ink From the point of preventing re-dissolution of the component (B), it is preferable to carry out under a nitrogen atmosphere, for example, at an oxygen concentration of 1000 ppm or less.
In addition to light irradiation, when heating, it processes normally at the temperature of 40 to 120 degreeC.
After applying the antifouling composition, it may be dried before light irradiation. Examples of the drying method include reduced-pressure drying or heat drying, and a method combining these drying methods. Moreover, when drying at normal pressure, it is preferable to dry at 30-110 degreeC. For example, when methyl ethyl ketone is used as a solvent for the antifouling composition, the temperature is in the range of room temperature to 80 ° C., preferably 40 ° C. to 70 ° C., and the time is 20 seconds to 3 minutes, preferably 30 seconds to 1 minute. The drying process can be performed.

(Formation of other layers)
When other layers are formed on the light-transmitting substrate, the other layer composition is applied before the antifouling composition is applied, and the other layers are formed by light irradiation and / or heating. That's fine.

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

  As reactive silica fine particles, trade name MIBK-SD (average primary particle size 12 nm, solid content 30%, MIBK solvent, photocurable group is methacryloyl group) manufactured by Nissan Chemical Industries, Ltd. was used.

As the PETA-derived urethane acrylate (1) of component (A), trade name BS577 (molecular weight 1000, hexafunctional) manufactured by Arakawa Chemical Industries, Ltd. was used.
As a PETA origin urethane acrylate (2) of (A) component, the brand name H120 (hexafunctional) by Negami Kogyo Co., Ltd. was used.
As the PETA-derived urethane acrylate (3) of the component (A), trade name HDPIPD (molecular weight 3000, hexafunctional) manufactured by Negami Kogyo Co., Ltd. was used.

As a comparative non-PETA-derived urethane acrylate (4), Nippon Kayaku Co., Ltd. product name DPHA40H (dipentaerythritol pentaacrylate as alcohol, reaction product of hexamethylene diisocyanate as isocyanate, molecular weight 7000, 10 functional) is used. It was.
As a non-PETA-derived urethane acrylate (5) for comparison, the product name UV1700B (dipentaerythritol pentaacrylate as an alcohol and isophorone diisocyanate as an isocyanate, molecular weight 2000, 10 functional) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. is used. It was.
As comparative non-PETA-derived urethane acrylate (6), trade name UN904 (dipentaerythritol pentaacrylate as alcohol, reaction product of hexamethylene diisocyanate as isocyanate, molecular weight 4900, 10 functional) manufactured by Negami Kogyo Co., Ltd. was used. .

As the other binder component (1), DPHA (hexafunctional, molecular weight 578) manufactured by Nippon Kayaku Co., Ltd. was used.
As other binder component (2), trade name M315 (molecular weight 423, trifunctional acrylate monomer) manufactured by Toagosei Co., Ltd. was used.
As the other binder component (3), trade name M215 (molecular weight 333, bifunctional acrylate monomer) manufactured by Toagosei Co., Ltd. was used.
As another binder component (4), trade name beam set DK1 (weight average molecular weight 20000, solid content 75%, MIBK solvent) manufactured by Arakawa Chemical Industries, Ltd. was used.

As the reactive fluorine compound of the component (B), trade name OPTOOL DAC manufactured by Daikin Industries, Ltd. was used.
As a comparative antifouling agent (1), DIC Corporation trade name MCF350-5 (fluorine-containing antifouling agent having no photocurable group)
As a comparative antifouling agent (2), trade name BYKUV3500 (silicon (silicone) -containing antifouling agent having a photocurable group) manufactured by Big Chemie Japan Co., Ltd.
As a polymerization initiator, Irgacure (Irg) 184 manufactured by Ciba Japan Co., Ltd. was used.
As the light-transmitting substrate (1), a TAC substrate manufactured by Fuji Film Co., Ltd., trade name TF80UL (thickness 80 μm) was used.
As the light-transmitting substrate (2), a PET substrate manufactured by Toray Industries, Inc., trade name U46 (thickness 125 μm, primer layer thickness 100 nm) was used.

Abbreviations for each compound are as follows.
PETA: Pentaerythritol triacrylate DPHA: Dipentaerythritol hexaacrylate DPPA: Dipentaerythritol pentaacrylate MIBK: Methyl isobutyl ketone MEK: Methyl ethyl ketone PGME: Propylene glycol monomethyl ether PET: Polyethylene terephthalate TAC: Triacetyl cellulose

(Preparation of curable resin composition for antifouling surface layer)
Components of the composition shown below were blended to prepare curable resin compositions 1 to 3 for an antifouling surface layer.

(Curable resin composition for antifouling surface layer 1)
PETA: 100 parts by mass Optool DAC: 0.2 parts by mass (solid content conversion)
Irg184: 4 parts by mass MIBK: 50 parts by mass MEK: 50 parts by mass

(Curable resin composition 2 for antifouling surface layer)
PETA: 75 parts by mass Other binder components (1) DPHA: 25 parts by mass Optool DAC: 0.2 parts by mass (solid content conversion)
Irg184: 4 parts by mass MIBK: 50 parts by mass MEK: 50 parts by mass

(Curable resin composition 3 for antifouling surface layer)
PETA: 75 parts by mass Reactive silica fine particles: 25 parts by mass (in terms of solid content)
Optool DAC: 0.2 parts by mass (in terms of solid content)
Irg184: 4 parts by mass MIBK: 50 parts by mass MEK: 50 parts by mass

(Production of optical film)
Example 1
On one side of the TAC substrate (TF80UL), the antifouling surface layer curable resin composition 1 is applied and dried in a heat oven at a temperature of 70 ° C. for 60 seconds to evaporate the solvent in the coating film. In a nitrogen atmosphere, the coating film was cured by irradiating ultraviolet rays with an integrated light amount of 200 mJ / cm ² to form an antifouling surface layer having a thickness of 10 μm, and an optical film was produced.

(Example 2)
Optical film in the same manner as in Example 1 except that 50 parts by mass of PETA of the curable resin composition 1 for antifouling surface layer and 50 parts by mass of the urethane acrylate BS577 as the component (A) were added. Got.

(Example 3)
In Example 1, it replaced with PETA of the curable resin composition 1 for antifouling | stain-resistant surface layers, and obtained the optical film like Example 1 except having used 100 mass parts of urethane acrylate BS577 of (A) component. It was.

(Example 4)
In Example 1, an optical film was obtained in the same manner as in Example 1 except that the curable resin composition 2 for an antifouling surface layer was used instead of the curable resin composition 1 for an antifouling surface layer. .

(Examples 5 to 10)
In Example 4, each optical film was obtained in the same manner as in Example 4 except that the composition of the binder system was changed as shown in Table 1.

(Example 11)
In Example 1, it replaced with the curable resin composition 1 for antifouling surface layers, and obtained the optical film like Example 1 except having used the curable resin composition 3 for antifouling surface layers. .

(Examples 12 and 13)
In Example 1, the content in terms of solid content of the reactive fluorine compound (OPTOOL DAC) as the component (B) is shown in Table 1 with respect to the total mass of the total solid content of the curable resin composition for an antifouling surface layer. An optical film was obtained in the same manner as in Example 1 except that the values shown were changed.

(Examples 14 and 15)
In Example 2, each optical film was obtained in the same manner as in Example 2 except that the composition of the binder system was changed as shown in Table 1.

(Example 16)
In Example 1, it replaced with MEK50 mass part of the solvent, and except having used PGME50 mass part, it carried out similarly to Example 1, and obtained the optical film.

(Example 17)
In Example 1, an optical film was obtained in the same manner as in Example 1 except that the substrate was replaced with the TAC substrate (TF80UL) and the PET substrate (U46) was used.

(Comparative Examples 1 and 2)
In Example 1, the content in terms of solid content of the reactive fluorine compound (OPTOOL DAC) as the component (B) is shown in Table 1 with respect to the total mass of the total solid content of the curable resin composition for an antifouling surface layer. An optical film was obtained in the same manner as in Example 1 except that the values shown were changed.

(Comparative Examples 3 to 9)
In Example 4, each optical film was obtained in the same manner as in Example 4 except that the composition of the binder system was changed as shown in Table 1.

(Comparative Example 10)
In Example 1, an optical film was obtained in the same manner as in Example 1 except that MCF350-5 was used in place of the reactive fluorine compound as the component (B) instead of Optool DAC.

(Comparative Example 11)
In Example 1, an optical film was obtained in the same manner as in Example 1 except that BYKUV3500 was used in place of the reactive fluorine compound of component (B) instead of OPTOOL DAC.

  Table 1 below summarizes the composition of the reactive silica fine particles and other binder components that are essential and optional components of the compositions used in Examples 1 to 17 and Comparative Examples 1 to 11.

(Evaluation of optical film)
About the optical film of the said Example and comparative example, as shown below, it measured about abrasion resistance, antifouling property (saponification resistance), the state of a coating surface, and pencil hardness. The results are shown in Table 2.

(Measurement of scratch resistance)
Using the # 0000 steel wool, the outermost surface of the optical film of the above examples and comparative examples was visually observed under a fluorescent lamp for the presence or absence of scratches on the coating film after changing the friction load by 100 g by 10 reciprocations. The highest load that was not damaged was measured.

(Evaluation of antifouling and saponification resistance)
The optical films of the above examples and comparative examples were immersed in a 2N sodium hydroxide aqueous solution at a temperature of 55 ° C. for 2 minutes (saponification treatment), and the contact angles for water and hexadecane on the outermost surface before and after the saponification treatment were In accordance with JIS R 3257 (1999) “Test method for wettability of substrate glass surface”, the measurement was performed using a microscope contact angle meter CA-QI series manufactured by Kyowa Interface Science Co., Ltd. at 25 ° C.

(Evaluation of paint surface)
About the optical film of the said Example and the comparative example, the light of the projector was permeate | transmitted and the image | video was observed visually, and the following references | standards evaluated.
Evaluation ○: There are no coating spots (repels, coating lines, and bubble defects). Evaluation ×: There are coating spots (repels, coating lines, or bubble defects).

(Measurement of pencil hardness)
About the optical film of the said Example and a comparative example, after conditioning for 2 hours on the conditions of temperature 25 degreeC and relative humidity 60%, the pencil hardness test (4.9N load) prescribed | regulated to JISK5600-5-4 (1999). The highest hardness that was not damaged was determined.

(Summary of results)
From Table 2, the optical films of Examples 1 to 17 obtained good results with respect to scratch resistance, antifouling property, coating surface condition and hardness.
However, in Comparative Example 1 in which the content of the reactive fluorine compound as the component (B) was small, the state of the coating surface was poor and the slipping property of the coating film surface was insufficient, so that the scratch resistance was also low. After the saponification treatment, the contact angle with water and hexadecane was greatly reduced.
In Comparative Example 2 in which the content of the reactive fluorine compound as the component (B) was large, the scratch resistance was low, and the coating surface state was poor.
In Comparative Examples 3 to 9 in which the content of PETA or PETA-derived urethane acrylate is low, the reactive fluorine compound has a small amount of PETA or PETA-derived urethane acrylate as the component (A), and a phase with a binder component other than the component (A) Solubility decreased, and the state of the coated surface was poor during the drying process.
In Comparative Examples 10 and 11 using a conventional antifouling agent instead of the reactive fluorine compound of the component (B), the contact angle with respect to water and hexadecane after saponification treatment was greatly reduced, and the antifouling property was low. .

1, 2, 3, 4 Optical film 10 Light transmissive substrate 20 Antifouling surface layer 21 Antifouling hard coat layer 22 Antifouling layer 30 Silica fine particles cured with reactive silica fine particles 40 Antistatic layer 50 Low refractive index layer

Claims (2)

(A) Binder system containing pentaerythritol triacrylate and / or urethane acrylate composed of a reaction product of pentaerythritol triacrylate and isocyanate , (B) a reactive fluorine compound represented by the following general formula (1) , and the above ( Reactive silica fine particles having cross-linking reactivity with the component (A) and the component (B) are included, the component (A) is included in an amount of 60% by mass or more based on the total mass of the binder system, and the component (B) Is contained in an amount of 0.005 to 3% by mass based on the total mass of the total solid content of the antifouling surface layer curable resin composition.

(In general formula (1), n is an integer of 1-5.) An optical film having an antifouling surface layer on the outermost surface on one side of a light-transmitting substrate,
The said antifouling surface layer consists of hardened | cured material of the curable resin composition for antifouling surface layers of the said Claim 1 , The optical film characterized by the above-mentioned.

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