JP2023092527A - hard coat film - Google Patents

Abstract

To provide a hard coat film which is excellent in initial adhesion between an easily adhering layer and a hard coat layer provided on a cycloolefin polymer-based film, and light-resistant adhesiveness.SOLUTION: A hard coat film has a hard coat layer containing an ultraviolet curable resin, an ultraviolet absorber and a dye stacked on at least one surface of a cycloolefin polymer-based film through an easy adhering layer composed of an ultraviolet curable resin containing inorganic fine particles, wherein the ultraviolet absorber is a combination of a benzotriazole-based ultraviolet absorber and a hydroxyphenyl triazine-based ultraviolet absorber, a maximum absorption wavelength (λmax) of the ultraviolet absorber is within a range of 350-380 nm, a maximum absorption wavelength (λmax) of the dye is within a range of 395-415 nm, and the hard coat film satisfies conditions (A) to (D). (A) Thickness of the easily adhering layer of 0.1-2.0 μm, (B) thickness of the hard coat layer of 1.0-10 μm, (C) residual ratios of the hard coat layer and the easily adhering layer measured by a cross cutting method of JIS-K5600-5-6 of 100%, and (D) residual ratios of the hard coat layer and the easily adhering layer measured by the cross cutting method after having been irradiated with ultraviolet rays at an irradiance of 500 W/m2 for 100 hours (light resistance test) under an environment of a temperature of 63°C and relative humidity of 50% of 100%.SELECTED DRAWING: None

Description

The present invention relates to a hard coat film used for optical members. More particularly, the present invention relates to a hard coat film that can be used as a protective film for display device parts such as panel displays such as organic electroluminescence (EL) displays, liquid crystal displays (LCDs) and plasma displays, and display devices such as touch panels.

For example, the display surfaces of displays such as organic electroluminescence (EL) displays and liquid crystal displays (LCDs) are required to be scratch-resistant so as to prevent deterioration of visibility due to damage during handling. there is Therefore, a hard coat film obtained by providing a hard coat layer on a base film is generally used to impart scratch resistance to the display surface of the display.

In recent years, along with the thinning and weight reduction of displays, the thinning of their constituent members is progressing. For example, hard coat films used for polarizing plates of displays are becoming thinner. When the hard coat film becomes thin, the dimensional stability of the polarizing plate is lowered, and the problem of curling of the polarizing plate under high temperature or high humidity drying occurs.
Therefore, as a method for solving this problem, a cycloolefin polymer film having low hygroscopicity (low moisture permeability) and excellent dimensional stability is used as the base film of the hard coat film.

However, unlike acrylic films and polyester films, this cycloolefin polymer film has a small number of polar groups on the film surface (non-polarity). However, there is a problem that the UV-curing hard coating material used does not adhere to the surface.

In order to improve the adhesion between the cycloolefin polymer film and the hard coat layer, the surface of the cycloolefin polymer film is modified (hydrophilized) by corona treatment, plasma treatment, etc. before the hard coat is applied. A method of obtaining adhesion by forming a compatible layer at the interface between the hard coat layer and the cycloolefin polymer film substrate using a soluble hydrocarbon solvent such as toluene, and a method of providing an anchor layer on the cycloolefin polymer film ( For example, patent document 1 etc.) etc. are generally known.

JP 2006-110875 A

However, the adhesion by the surface modification (hydrophilization) method of the cycloolefin polymer film lacks stability, and even if 100% of the initial adhesion can be secured, adhesion failure is likely to occur particularly over time, resulting in durability. There is a problem that adhesion cannot be obtained.

In addition, the method of forming a compatible layer puts an excessive load on the cycloolefin polymer film substrate when applying the hard coat. There is a problem that cracks occur. In particular, the chemical cracks tend to occur more frequently as the cycloolefin polymer film substrate becomes thinner.

As for the method of providing the anchor layer, it is common to use a modified polyolefin resin for the anchor layer. Hydrocarbon solvents such as toluene cannot be used in hard coat paints, which poses a problem in paint design.

On the other hand, for the purpose of improving the durability (light resistance) of the light-emitting element of the organic EL display, it is necessary to cut ultraviolet (UV) rays on the surface side of the display. Generally, UV cut performance is based on the transmittance at a wavelength of 380 nm, but recently, the transmittance in the range of 390 nm to 410 nm has become the standard for protection of light emitting elements.

Ultraviolet absorbers, dyes, and the like are known for adjusting the transmittance in the 390 nm to 410 nm region, and hydrocarbon solvents such as toluene are good solvents for all of these. That is, for the purpose of improving the durability (light resistance) of the light emitting element of the organic EL display by the hard coat film, a hard coat paint containing an ultraviolet absorber, a pigment, etc. for adjusting the transmittance in the 390 nm to 410 nm region is used. Considering the solubility of the material, it is necessary to use a hydrocarbon solvent such as toluene as a solvent in the hard coat paint. However, it is difficult to apply due to concerns about the occurrence of chemical cracks.

Therefore, the first object of the present invention is to use a cycloolefin polymer-based film as a substrate, and to provide adhesion (initial adhesion and light-resistant adhesion) with an easy-adhesion layer and a hard coat layer provided on the substrate film. Secondly, the easy-adhesion layer provided on the base film has good solvent resistance to hydrocarbon-based solvents, and a hydrocarbon-based solvent is provided on the easy-adhesion layer. To provide a hard coat film capable of obtaining a good coating appearance even when directly coated with a hard coat paint containing a solvent. Third, it is used as a protective film for the surface of an organic EL display. In this case, it is possible to improve the durability (light resistance) of the light-emitting elements of the organic EL display without adversely affecting the display color and brightness of the organic EL display, and to suppress deterioration of the display of the organic EL display. It is to provide a coated film.

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in order to solve the above problems, the present inventors have found that the above problems can be solved by the invention having the following configuration.
That is, the present invention has the following configurations.

(First Invention)
A hard coat layer containing an ultraviolet curable resin, an ultraviolet absorber and a dye is laminated on at least one side of a cycloolefin polymer film having a thickness of 50 μm or less via an easy-adhesion layer made of an ultraviolet curable resin containing inorganic fine particles. and satisfying the following conditions (A) to (D).
(A) The thickness of the easy-adhesion layer is in the range of 0.1 to 2.0 μm.
(B) The thickness of the hard coat layer is in the range of 1.0 to 10.0 μm.
(C) The residual rate of the hard coat layer and the easily adhesive layer measured by the cross-cut method of JIS-K5600-5-6 of the hard coat film is 100%.
(D) The hard coat film was irradiated with ultraviolet rays for 100 hours (light resistance test) at an irradiance of 500 W/m ² in an environment of a temperature of 63 ° C. and a relative humidity of 50%, and then JIS-K5600-5- Both the residual rates of the hard coat layer and the easily adhesive layer measured by the cross-cut method of No. 6 are 100%.

(Second invention)
A first characterized in that the hard coat film further satisfies the following condition (E), and the light reduction rate (%) at each wavelength calculated by the following formula 1 satisfies the following conditions (F) to (P): It is a hard coat film according to the invention.
(E) The b* value is 7.0 or less.
Formula 1) Light reduction rate (%) at each wavelength = (transmittance of the cycloolefin polymer film alone at the wavelength - transmittance of the hard coat film at the wavelength) / cycloolefin polymer film alone at the wavelength The light transmittance (F) of 350 nm wavelength is 95.0% or more.
(G) The light reduction rate at a wavelength of 360 nm is 95.0% or more.
(H) The light reduction rate at a wavelength of 370 nm is 95.0% or more.
(I) The light reduction rate at a wavelength of 380 nm is 95.0% or more.
(J) The light reduction rate at a wavelength of 390 nm is 95.0% or more.
(K) The light reduction rate at a wavelength of 400 nm is 95.0% or more.
(L) The light reduction rate at a wavelength of 410 nm is 95.0% or more.
(M) Light reduction rate at a wavelength of 420 nm is 75.0% or less.
(N) The light reduction rate at a wavelength of 430 nm is 30.0% or less.
(O) Light reduction rate at 440 nm wavelength is 7.0% or less.
(P) The reduction rate of light at a wavelength of 450 nm is 2.0% or less.

(Third Invention)
For the hard coat film, in an environment with a temperature of 63 ° C. and a relative humidity of 50%, an irradiance of 500 W / m ² , and after irradiating ultraviolet rays for 100 hours (light resistance test), each wavelength calculated by the following formula 2 The hard coat film according to the first or second invention, wherein the absolute value of the rate of change (Δ%) of the light transmittance in the condition satisfies the following conditions (Q) to (AA).
Formula 2) Change rate of light transmittance at each wavelength (Δ%) = Transmittance at the wavelength after the light resistance test of the hard coat film - Transmittance at the wavelength before the light resistance test of the hard coat film (Q ) The absolute value of the rate of change in light transmittance at a wavelength of 350 nm is 1.0% or less.
(R) The absolute value of the rate of change in light transmittance at a wavelength of 360 nm is 1.0% or less.
(S) The absolute value of the rate of change in light transmittance at a wavelength of 370 nm is 1.0% or less.
(T) The absolute value of the rate of change in light transmittance at a wavelength of 380 nm is 1.0% or less.
(U) The absolute value of the rate of change in light transmittance at a wavelength of 390 nm is 5.0% or less.
(V) The absolute value of the rate of change in light transmittance at a wavelength of 400 nm is 10.0% or less.
(W) The absolute value of the rate of change in light transmittance at a wavelength of 410 nm is 30.0% or less.
(X) The absolute value of the rate of change in light transmittance at a wavelength of 420 nm is 30.0% or less.
(Y) The absolute value of the rate of change in light transmittance at a wavelength of 430 nm is 10.0% or less.
(Z) The absolute value of the rate of change in light transmittance at a wavelength of 440 nm is 5.0% or less.
(AA) The absolute value of the rate of change in light transmittance at a wavelength of 450 nm is 5.0% or less.

(Fourth Invention)
The first to third inventions, wherein the maximum absorption wavelength (λmax) of the ultraviolet absorber is in the range of 350 nm to 380 nm, and the maximum absorption wavelength (λmax) of the dye is in the range of 395 nm to 415 nm. 2. A hard coat film according to any one of .

(Fifth Invention)
The hard coat film according to any one of the first to fourth inventions, wherein the ultraviolet absorber is a combination of a benzotriazole-based ultraviolet absorber and a hydroxyphenyltriazine-based ultraviolet absorber.

(Sixth Invention)
The hard coat film according to any one of the first to fifth inventions, wherein the dye is a cyanine dye.

According to the present invention, a cycloolefin polymer-based film is used as a base material, and even for such a base material with few polar groups and poor adhesion, the easy-adhesion layer and the hard coat layer provided on the base film can be combined. A hard coat film having excellent adhesion (initial adhesion and light resistance adhesion) can be provided.
Further, according to the present invention, the easy-adhesion layer provided on the base film has good solvent resistance against hydrocarbon solvents, and a hard coat paint containing a hydrocarbon-based solvent is applied on the easy-adhesion layer. It is possible to provide a hard coat film capable of obtaining a good coating appearance even when directly coated.
In addition, according to the present invention, when used as a protective film on the surface of an organic EL display, the display color and brightness of the organic EL display are not adversely affected, and the durability (light resistance) of the light emitting element of the organic EL display is improved. It is possible to provide a hard coat film capable of improving the display quality of an organic EL display and suppressing display deterioration.
In particular, the hard coat film of the present invention is suitable when a thin cycloolefin polymer film is used as a substrate.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments for carrying out the present invention will be described in detail below, but the present invention is not limited to the following embodiments.
In this specification, "○○ to △△" shall mean "○○ or more and △△ or less" unless otherwise specified.

As described in the first invention, the hard coat film of the present invention is a cycloolefin polymer film having a thickness of 50 μm or less, which is provided on at least one side with an easy-adhesion layer made of an ultraviolet-curable resin containing inorganic fine particles. It is characterized by laminating a hard coat layer containing a curable resin, an ultraviolet absorber and a dye, and satisfying the following conditions (A) to (D).
(A) The thickness of the easy-adhesion layer is in the range of 0.1 to 2.0 μm.
(B) The thickness of the hard coat layer is in the range of 1.0 to 10.0 μm.
(C) The residual rate of the hard coat layer and the easily adhesive layer measured by the cross-cut method of JIS-K5600-5-6 of the hard coat film is 100%.
(D) The hard coat film was irradiated with ultraviolet rays for 100 hours (light resistance test) at an irradiance of 500 W/m ² in an environment of a temperature of 63 ° C. and a relative humidity of 50%, and then JIS-K5600-5- Both the residual rates of the hard coat layer and the easily adhesive layer measured by the cross-cut method of No. 6 are 100%.
The structure of this hard coat film will be described in detail below.

[Base film]
First, the base film of the hard coat film will be described.
In the present invention, a cycloolefin polymer excellent in transparency, heat resistance, dimensional stability, low moisture absorption (low moisture permeability), low birefringence, optical isotropy, etc. is used as the base film for the hard coat film. system film is used. Specifically, cycloolefin units are alternately or randomly polymerized in the polymer skeleton and have an alicyclic structure in the molecular structure, and are norbornene compounds, monocyclic cyclic olefins, cyclic conjugated dienes and vinyl alicyclic compounds. A cycloolefin copolymer film or a cycloolefin polymer film, which is a copolymer containing at least one compound selected from cyclic hydrocarbons, is targeted, and either one can be appropriately selected and used.

In the present invention, the thickness of the cycloolefin polymer film is appropriately selected depending on the application. is preferably 30 μm or less, and particularly preferably 30 μm or less. On the other hand, from the viewpoint of mechanical strength, handleability, etc., the thickness is preferably 10 μm or more.

In the present invention, when a hard coat layer is formed on one side of the cycloolefin polymer film via an easy-adhesion layer, a cycloolefin polymer film is formed on the back side of the cycloolefin polymer film on which the hard coat layer is not formed. For the purpose of preventing crimping during winding and improving the runnability of the film when forming the hard coat layer, polyethylene resin that has excellent releasability from the cycloolefin polymer film by co-extrusion when forming the cycloolefin polymer film. A film in which polypropylene resin or polyester resin is laminated as a protective layer may be used. Moreover, it is also possible to use the thing which stuck protective films, such as a polyethylene resin, a polypropylene resin, or a polyester resin, in which the weak adhesive layer is formed in the back surface.

Examples of the cycloolefin polymer-based film include commercially available Zeonor (trade name: manufactured by Nippon Zeon Co., Ltd.), Optica (trade name: manufactured by Mitsui Chemicals, Inc.), Arton (trade name: manufactured by JSR Corporation), Kozek (trade name: manufactured by Kurashiki Boseki Co., Ltd.) and the like.

[Easy adhesion layer]
Next, the easy-adhesion layer of the hard coat film will be described.
In the hard coat film of the present invention, the easy-adhesion layer is made of an ultraviolet curable resin containing inorganic fine particles.
In the present invention, the resin used in the easy adhesion layer is an ultraviolet curable resin, and is particularly limited as long as it is a transparent resin that is cured by irradiation with ultraviolet rays (hereinafter abbreviated as "UV"). However, for example, an acrylic resin whose basic skeleton is composed of a polymer of an acrylic acid ester or a methacrylic acid ester, a urethane acrylate resin having a urethane bond obtained by reacting an isocyanate group and a hydroxyl group, and an acrylic group, etc. can be preferably used. In order for the easy-adhesion layer to form a three-dimensional crosslinked structure, for example, a UV-curable polyfunctional acrylate having a plurality of functional groups such as (meth)acryloyloxy groups in the molecule is preferable. . Specific examples of UV-curable polyfunctional acrylates having multiple (meth)acryloyloxy groups in the molecule include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth) acrylates, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane ethoxy triacrylate, glycerin propoxy triacrylate, Ditrimethylolpropane tetraacrylate and the like can be mentioned. The polyfunctional acrylates may not only be used alone, but may also be used in combination of two or more.

By using an ultraviolet curable resin as the binder resin of the easy-adhesion layer, a solvent other than a hydrocarbon-based solvent is used in the easy-adhesion layer-forming coating solution (hereinafter also referred to as "easy-adhesion layer coating material"). be able to. Therefore, even if the coating material for the easy-adhesion layer is applied onto a cycloolefin polymer film substrate having low solvent resistance to hydrocarbon solvents such as toluene, the occurrence of chemical cracks in the cycloolefin polymer film substrate can be prevented. be able to. In addition, by using an ultraviolet curable resin as the binder resin of the easy adhesion layer, the cured easy adhesion layer has good solvent resistance against hydrocarbon solvents such as toluene. A hydrocarbon solvent such as toluene can be used as a solvent for the hard coat layer-forming coating liquid (hereinafter also referred to as "hard coat coating material") to be applied, which is advantageous in terms of coating design.

In addition, the UV-curable resin used in the easy adhesion layer preferably uses a monomer, oligomer, or polymer having a weight average molecular weight within the range of 500 to 3600, more preferably having a weight average molecular weight within the range of 500 to 3000. A weight average molecular weight of 500 to 2,400 is more preferred. If the weight-average molecular weight is less than 500, curing shrinkage when cured by UV irradiation is large, and the phenomenon (curling) in which the hard coat film is warped toward the hard coat layer side becomes large, causing problems during the subsequent processing steps. resulting in poor processability. On the other hand, if the weight-average molecular weight exceeds 3600, the hardness of the easy-adhesion layer will be insufficient, and the solvent resistance of the easy-adhesion layer to hydrocarbon solvents will be difficult to obtain, which is not suitable.

In addition to the above-described UV-curable resins, the resin contained in the easy-adhesion layer includes thermoplastic resins such as polyethylene, polypropylene, polystyrene, polycarbonate, polyester, acrylic, styrene-acrylic, and cellulose, and phenolic resins. , urea resins, unsaturated polyesters, epoxy resins, silicone resins, and other thermosetting resins may be blended within limits that do not impair the effects of the present invention.

In the present invention, the easy-adhesion layer contains inorganic fine particles. By containing inorganic fine particles in the easy-adhesion layer, the adhesion (initial adhesion and light-resistant adhesion) between the cycloolefin polymer film substrate and the easy-adhesion layer can be improved, and the easy-adhesion layer and the hard Adhesion (initial adhesion and light resistance adhesion) with the coat layer can be improved. By containing inorganic fine particles in the easy-adhesion layer, the easy-adhesion layer forms unevenness on the surface, and the contact interface between the substrate film and the hard coat layer is enlarged (increased surface area of the easy-adhesion layer), and furthermore, the adhesion is facilitated. The hard coat layer enters into the unevenness of the surface of the layer and hardens, acting like a wedge (anchoring force), and the effect of improving adhesion is generated. That is, the unevenness of the surface of the outermost layer of the easy-adhesion layer can be adjusted within a range in which the adhesion to the substrate film and the hard coat layer is optimal.

Examples of inorganic fine particles include fine particles of silica, alumina, zinc oxide, titanium oxide, cerium oxide, and the like. As for the particle size, for example, fine particles having an average particle size of 5 nm to 300 nm are preferably used. If the average particle size is less than 5 nm, the above effect of improving adhesion cannot be sufficiently obtained. On the other hand, if the average particle size exceeds 300 nm, the transparency of the easy-adhesion layer may decrease.

In the present invention, the blending amount of the inorganic fine particles is preferably 5 to 40 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin of the easy adhesion layer. If the amount of the inorganic fine particles to be blended is less than 5 parts by mass, the above effect of improving adhesion cannot be sufficiently obtained. On the other hand, if the blending amount exceeds 40 parts by mass, the transparency of the easy-adhesion layer is lowered.

The easy-adhesion layer coating material for forming the easy-adhesion layer contains a photopolymerization initiator. As such a photoinitiator, commercially available acetophenones such as IRGACURE 651 and IRGACURE 184 (both trade names: manufactured by BASF), and benzophenones such as IRGACURE 500 (trade name: manufactured by BASF) are used. can.

In addition, the easy-adhesion layer can be blended with a leveling agent for the purpose of adjusting surface properties (surface free energy, water contact angle, etc.) and improving coatability. Any known leveling agent such as a system, and adducts or mixtures thereof can be used. The blending amount is appropriately determined according to, for example, adjustment of surface properties and coatability.

In addition, as other additives added to the easy adhesion layer, defoaming agents, antifouling agents, antioxidants, antistatic agents, light stabilizers, etc., are added as necessary within a range that does not impair the effects of the present invention. May be blended.

The thickness (coating thickness) of the easy-adhesion layer in the present invention is preferably in the range of 0.1 μm to 2.0 μm. When the thickness of the easy-adhesion layer is less than 0.1 μm, the effect of improving the adhesion is not sufficiently obtained, and the solvent resistance of the easy-adhesion layer to hydrocarbon solvents is difficult to obtain. On the other hand, from the viewpoint of thinning the hard coat film, the thickness of the easy-adhesion layer is desirably 2.0 μm or less.

In addition to the ionizing radiation-curable resin, the easy-adhesion layer is a paint in which the inorganic fine particles, the photopolymerization initiator, and, if necessary, a leveling agent, other additives, etc. are dissolved or dispersed in an appropriate solvent ( Easy adhesion layer coating) is applied onto the cycloolefin polymer film (base film), dried, and then cured by UV irradiation. In this case, the solvent can be appropriately selected according to the solubility of the above-mentioned resin or the like contained therein, and should be a solvent capable of uniformly dissolving or dispersing at least the solid content (resin, photopolymerization initiator, other additives, etc.). , and the use of an organic solvent having a boiling point of 50° C. to 120° C., for example, is preferred from the viewpoint of workability and drying properties during coating. Examples of such organic solvents include ester solvents such as methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate and methyl lactate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; Alcohol-based solvents such as ethanol, isopropyl alcohol, n-propyl alcohol, and butanol-based solvents can be used singly or in combination. As described above, by using an ultraviolet curable resin as the binder resin for the easy adhesion layer, a solvent other than a hydrocarbon solvent can be used as the easy adhesion layer coating solvent. This prevents chemical cracks in the cycloolefin polymer film substrate even when the coating material for the easy adhesion layer is applied onto the cycloolefin polymer film substrate, which has low resistance to hydrocarbon solvents such as toluene. can do.

Examples of the method for applying the easy-adhesion layer coating material on the base film include gravure coating, micro gravure coating, fountain bar coating, slide die coating, slot die coating, screen printing, and spray coating. It can be coated by a known coating method such as a method. The paint applied on the cycloolefin polymer film is usually dried at a temperature of about 50 to 120°C to remove the solvent while appropriately adjusting the drying conditions (temperature in the drying oven, wind speed in the oven, drying time, etc.). to form a coating film.

In addition, the amount of ultraviolet (UV) irradiation after the formation of the easy-adhesion layer coating film may be an irradiation amount necessary to give the easy-adhesion layer an appropriate hardness, depending on the type of the ultraviolet-curable resin. can be set as appropriate.

As for the amount of ultraviolet irradiation, it is preferable to set the integrated amount of light to 50 to 300 mJ/cm ² , for example. If the integrated amount of light is less than 50 mJ/cm ² , sufficient adhesion between the cycloolefin polymer film substrate and the easily adhesive layer cannot be obtained. On the other hand, if the integrated amount of light exceeds 300 mJ/cm ² , the cycloolefin polymer film substrate may be deformed and the appearance may be impaired.

Further, in the present invention, it is preferable that the surface free energy of the easy-adhesion layer surface is 22 mN/m or more.
The term "surface free energy" as used herein is defined as "free energy per unit area of the surface", and refers to excess energy on the surface of the easy-adhesion layer compared to the inside (bulk) of the layer. The higher the surface free energy of a solid, the easier it is for gases and fine particles to be adsorbed, the easier it is for liquids to get wet, and the easier it is for them to adhere to other solids.

This surface free energy can be measured by analyzing the contact angle between water and hexadecane by the Kaelble-Uy method using a contact angle meter or the like. Specifically, the surface free energy of the easy adhesion layer is measured by dropping 1 μL of water (pure water) on the surface of the easy adhesion layer using a fully automatic contact angle meter DM-701 manufactured by Kyowa Interface Science Co., Ltd. Seconds later, the contact angle was measured, 1 μL of n-hexadecane was dropped on the surface of the easy-adhesion layer, and after 30 seconds, the contact angle of water and the contact angle of n-hexadecane were measured. - is a value calculated by the method of Uy.

The value of the surface free energy of the easy-adhesion layer indicates an index of the adhesion of the hard coat layer to the resin. Since the intermolecular force between the molecules of and the molecules of the easy-adhesion layer increases, it contributes to the improvement of the adhesion of the hard coat layer. If the surface free energy is less than 22 mN/m, the adhesion to the hard coat layer may be deteriorated, and cissing defects may occur when the hard coat layer is applied.
In the present invention, it is particularly preferable that the easy-adhesion layer has a surface free energy of 25 mN/m or more.
Also, if the surface free energy of the easy-adhesion layer is too large, stains are likely to adhere, causing problems such as contamination with foreign matter and reduced scratch resistance. It is preferably 38 mN/m or less, more preferably 35 mN/m or less.

The surface free energy of the easy-adhesion layer can be adjusted, for example, by adding a leveling agent to the easy-adhesion layer (type and amount of leveling agent added, etc.).

Further, in the present invention, it is preferable that the contact angle of water on the surface of the easy-adhesion layer is 90 degrees or less.
The contact angle of water on the surface of the easy-adhesion layer was determined by dropping 1 μL of water (pure water) on the surface of the easy-adhesion layer using a fully automatic contact angle meter DM-701 manufactured by Kyowa Interface Science Co., Ltd., and after 30 seconds, It is obtained by measuring the contact angle.

The value of the contact angle of water on the surface of the easy-adhesion layer is one indicator of adhesion to the resin used in the hard coat layer. When the angle is 90 degrees or less, the intermolecular force between the molecules of the hard coat layer resin and the molecules of the easy adhesion layer is increased, which contributes to the improvement of the adhesion of the hard coat layer. On the other hand, if the contact angle is larger than 90 degrees, the adhesion to the hard coat layer may deteriorate, or repelling defects may occur during coating of the hard coat layer.
In the present invention, it is particularly preferable that the contact angle of water on the surface of the easy adhesion layer is 85 degrees or less.
If the water contact angle is too low, the scratch resistance of the easy-adhesion layer tends to be poor, and the water contact angle is desirably 50 degrees or more.

The contact angle of water on the surface of the easy-adhesion layer can be adjusted, for example, by adding a leveling agent to the easy-adhesion layer (type and amount of leveling agent added, etc.).

[Hard coat layer]
Next, the hard coat layer of the hard coat film will be described.
In the present invention, the hard coat layer contains at least an ultraviolet curable resin, an ultraviolet absorber and a dye.
In the present invention, the resin contained in the hard coat layer particularly imparts surface hardness (pencil hardness, scratch resistance) to the hard coat layer, and can adjust the degree of cross-linking by the amount of exposure to ultraviolet rays. Therefore, it is preferable to use an ultraviolet curable resin in that the surface hardness of the hard coat layer can be adjusted.

The ultraviolet curable resin used in the present invention is not particularly limited as long as it is a transparent resin that cures when irradiated with ultraviolet rays (UV). A UV-curable polyfunctional acrylate having three or more (meth)acryloyloxy groups in one molecule to form a structure is preferred. Specific examples of UV-curable polyfunctional acrylates having three or more (meth)acryloyloxy groups in the molecule include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate. ) acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane ethoxy triacrylate, glycerin propoxy triacrylate , ditrimethylolpropane tetraacrylate, and the like. The polyfunctional acrylates may not only be used alone, but may also be used in combination of two or more.

Furthermore, the UV-curable resin used for the hard coat layer preferably uses a monomer, oligomer or polymer having a weight average molecular weight within the range of 500 to 3600, more preferably having a weight average molecular weight within the range of 500 to 3000. , and a weight average molecular weight of 500 to 2,400 are more preferred. If the weight-average molecular weight is less than 500, curing shrinkage when cured by UV irradiation is large, and the phenomenon (curling) in which the hard coat film is warped toward the hard coat layer side becomes large, causing problems during the subsequent processing steps. resulting in poor processability. On the other hand, if the weight average molecular weight exceeds 3600, the flexibility of the hard coat layer is increased, but the hardness is insufficient, which is not suitable.

When the weight-average molecular weight of the UV-curable resin used for the hard coat layer is less than 1,500, the number of functional groups per molecule is desirably 3 or more and less than 10. Further, when the weight average molecular weight of the UV curable resin is 1500 or more, the number of functional groups in one molecule is desirably 3 or more and 20 or less. Within the above range, curling can be suppressed and appropriate processability can be maintained.

As the resin contained in the hard coat layer, thermoplastic resins such as polyethylene, polypropylene, polystyrene, polycarbonate, polyester, acrylic, styrene-acrylic, cellulose, etc., and phenolic resins are used in addition to the ultraviolet-curable resins described above. Thermosetting resins such as urea resins, unsaturated polyesters, epoxies, silicone resins, etc. may be blended within a range that does not impair the hardness and scratch resistance of the hard coat layer.

In the present invention, the hard coat layer contains an ultraviolet absorber and a dye in addition to the ultraviolet curable resin.

As the ultraviolet absorbent used in the present invention, an ultraviolet absorbent having a maximum absorption wavelength (λmax) of 350 nm to 380 nm is particularly suitable.
In the present invention, for example, it is preferable to use a benzotriazole-based ultraviolet absorber, a hydroxyphenyltriazine-based ultraviolet absorber, or the like, and it is particularly preferable to use these benzotriazole-based ultraviolet absorbers and hydroxyphenyltriazine-based ultraviolet absorbers in combination. .

As the dye used in the present invention, a dye having a maximum absorption wavelength (λmax) in the range of 395 nm to 415 nm is particularly suitable.
In the present invention, for example, the dye is preferably a cyanine dye.

In the hard coat film of the present invention, the hard coat layer contains the above-described ultraviolet absorber and dye, so that the spectral characteristics (light reduction rate at each wavelength of 350 nm to 450 nm, change rate of light transmittance after light resistance test ) can satisfy the scope of the present invention.
In the present invention, the blending amount of the ultraviolet absorber is preferably 1 to 30 parts by weight with respect to 100 parts by weight of the ultraviolet curable resin of the hard coat layer. If the blending amount of the ultraviolet absorber is less than 1 part by mass, the spectral characteristics of the present invention cannot be sufficiently satisfied. On the other hand, if the blending amount exceeds 30 parts by mass, it is difficult for the b* value, which is an index of yellowness, to satisfy the range of the present invention, and the hardness and adhesion of the hard coat layer are insufficient.
Further, the amount of the dye to be blended is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin of the hard coat layer. If the blending amount of the ultraviolet absorber is less than 0.1 parts by mass, the spectral characteristics of the present invention cannot be sufficiently satisfied. On the other hand, if the blending amount exceeds 10 parts by mass, it is difficult for the b* value, which is an index of yellowness, to satisfy the range of the present invention, and the hardness and adhesion of the hard coat layer are insufficient.

It is also possible to further improve the surface hardness (scratch resistance) by incorporating inorganic oxide fine particles into the hard coat layer. In this case, the average particle size of the inorganic oxide fine particles is preferably in the range of 5 to 50 nm, more preferably in the range of 10 to 40 nm. If the average particle size is less than 5 nm, it is difficult to obtain sufficient surface hardness. On the other hand, if the average particle size exceeds 50 nm, the glossiness and transparency of the hard coat layer are likely to be reduced, and the flexibility may also be reduced.

In the present invention, examples of the inorganic oxide fine particles include alumina and silica. Among these, alumina containing aluminum as a main component is particularly suitable because it has high hardness and can be effective with a smaller addition amount than silica.

In the present invention, the content of the inorganic oxide fine particles is preferably 0.1 to 10.0 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin of the hard coat layer. If the content of the inorganic oxide fine particles is less than 0.1 parts by mass, it is difficult to obtain the effect of improving the surface hardness (scratch resistance). On the other hand, when the content exceeds 10.0 parts by mass, the haze increases, which is not preferable.

The hard coat paint for forming the hard coat layer may contain a photopolymerization initiator. As such a photoinitiator, commercially available acetophenones such as IRGACURE 651 and IRGACURE 184 (both trade names: manufactured by BASF), and benzophenones such as IRGACURE 500 (trade name: manufactured by BASF) are used. can.

A leveling agent can be used in the hard coat layer for the purpose of improving coatability. For example, known leveling agents such as fluorine-based, acrylic-based, siloxane-based, and adducts or mixtures thereof can be used. is. The blending amount can be in the range of 0.03 to 3.0 parts by mass per 100 parts by mass of the solid content of the resin of the hard coat layer. In addition, in touch panel applications, etc., it is required to have anti-adhesiveness using an optically transparent adhesive OCR for the purpose of bonding with the cover glass (CG) of the touch panel terminal, the transparent conductive member (TSP), the liquid crystal module (LCM), etc. In some cases, it is preferable to use an acrylic leveling agent or a fluorine-based leveling agent with a high surface free energy (approximately 30 mN/m or more).

Other additives to be added to the hard coat layer include antifoaming agents, surface tension modifiers, antifouling agents, antioxidants, antistatic agents, light stabilizers, etc., within the range that does not impair the effects of the present invention. may be blended according to

The hard coat layer is prepared by dissolving and dispersing the above ultraviolet absorber, pigment, photopolymerization initiator, other additives, etc. in an appropriate solvent in addition to the above ultraviolet curable resin. It is formed by applying it on the easy-adhesion layer, drying it, and then curing it by irradiating it with UV. The solvent can be appropriately selected according to the solubility of the resin to be mixed, and is a solvent capable of uniformly dissolving or dispersing at least the solid content (resin, ultraviolet absorber, dye, photopolymerization initiator, other additives, etc.). I wish I had. Examples of such solvents include aromatic solvents such as toluene, xylene and n-heptane, aliphatic solvents such as cyclohexane, methylcyclohexane and ethylcyclohexane, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate and acetic acid. Known organic solvents such as ester solvents such as butyl and methyl lactate, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, and alcohol solvents such as methanol, ethanol, isopropyl alcohol and n-propyl alcohol alone Alternatively, several types can be appropriately combined and used.
According to the present invention, since the easy-adhesion layer has good solvent resistance to hydrocarbon-based solvents, a hard coat paint containing a hydrocarbon-based solvent such as toluene is directly coated on the easy-adhesion layer. A good coating appearance can be obtained even when the coating is applied.

The coating method of the hard coat paint for forming the hard coat layer is not particularly limited, but gravure coating, micro gravure coating, fountain bar coating, slide die coating, slot die coating, screen printing. After coating by a known coating method such as a coating method, a spray coating method, etc., it is usually dried at a temperature of about 50 to 120°C.

The amount of ultraviolet (UV) irradiation after the formation of the hard coat layer coating film may be any amount necessary to give the hard coat layer sufficient hard properties, and it is appropriate according to the type of the ultraviolet curable resin. can be set.

In the present invention, the thickness (coating thickness) of the hard coat layer is, for example, preferably in the range of 1.0 μm to 10.0 μm, more preferably in the range of 1.5 μm to 5.0 μm. . If the coating thickness is less than 1.0 μm, the necessary hard properties (for example, scratch resistance) are lowered, which is not preferable. On the other hand, when the coating thickness exceeds 10.0 μm, curling is likely to occur strongly, resulting in deterioration in handleability in the manufacturing process, etc., and is not preferable from the viewpoint of thinning of the hard coat film.

As described above, the hard coat film of the present invention is a cycloolefin polymer-based film having a thickness of 50 μm or less, and is provided on at least one side with an ultraviolet-curable resin and an easy-adhesion layer made of an ultraviolet-curable resin containing inorganic fine particles. A hard coat layer containing an ultraviolet absorber and a dye is laminated.

The hard coat film of the present invention further satisfies the following conditions (A) to (D).
(A) The thickness of the easy-adhesion layer is in the range of 0.1 to 2.0 μm.
(B) The thickness of the hard coat layer is in the range of 1.0 to 10.0 μm.
(C) The residual rate of the hard coat layer and the easily adhesive layer measured by the cross-cut method of JIS-K5600-5-6 of the hard coat film is 100%.
(D) The hard coat film was irradiated with ultraviolet rays for 100 hours (light resistance test) at an irradiance of 500 W/m ² in an environment of a temperature of 63 ° C. and a relative humidity of 50%, and then JIS-K5600-5- Both the residual rates of the hard coat layer and the easily adhesive layer measured by the cross-cut method of No. 6 are 100%.

Conditions (A) and (B) are as described above.
Moreover, the hard coat film of the present invention satisfies the above conditions (C) and (D). As a result, the adhesion ( A hard coat film excellent in initial adhesion and light resistance adhesion can be obtained. Further details of the adhesion test by the crosscut method of JIS-K5600-5-6 and the light resistance test will be described later in Examples.

The hard coat film of the present invention further satisfies the following condition (E), and further satisfies the following conditions (F) to (P) in terms of light reduction rate (%) at each wavelength.
(E) The b* value is 7.0 or less.
(F) The light reduction rate at a wavelength of 350 nm is 95.0% or more.
(G) The light reduction rate at a wavelength of 360 nm is 95.0% or more.
(H) The light reduction rate at a wavelength of 370 nm is 95.0% or more.
(I) The light reduction rate at a wavelength of 380 nm is 95.0% or more.
(J) The light reduction rate at a wavelength of 390 nm is 95.0% or more.
(K) The light reduction rate at a wavelength of 400 nm is 95.0% or more.
(L) The light reduction rate at a wavelength of 410 nm is 95.0% or more.
(M) Light reduction rate at a wavelength of 420 nm is 75.0% or less.
(N) The light reduction rate at a wavelength of 430 nm is 30.0% or less.
(O) Light reduction rate at 440 nm wavelength is 7.0% or less.
(P) The reduction rate of light at a wavelength of 450 nm is 2.0% or less.

Here, the light beam reduction rate at each wavelength is calculated by the following formula 1.
Formula 1) Light reduction rate (%) at each wavelength = (transmittance of the cycloolefin polymer film alone at the wavelength - transmittance of the hard coat film at the wavelength) / cycloolefin polymer film alone at the wavelength Transmittance of

The b* value defined in the above condition (E) is an index of the noble color tone, and the larger the value, the stronger the noble color tone.
A specific method for measuring the b* value and the light transmittance at each wavelength will be described later in Examples.

The hard coat film of the present invention is provided with a hard coat layer made of an ultraviolet curable resin containing the above-described ultraviolet absorber and dye, and the hard coat that satisfies the optical properties of the present invention, that is, the above conditions (E) to (P). It's a film. As a result, the hard coat film of the present invention suppresses the b* value, which is an index of yellowness, and does not adversely affect the display color of the organic EL display, and causes deterioration of some polymers, fading and discoloration of pigments, etc. damage of 350 nm to 400 nm is 95% or more, it is possible to suppress damage such as deterioration of some polymers and fading and discoloration of pigments. Furthermore, in order to improve the durability (light resistance) of the light-emitting elements of recent organic EL displays, it is required to sufficiently reduce the light transmittance of 390 nm to 410 nm in order to protect the light-emitting elements. The hard coat film of the invention can improve the durability (light resistance) of light-emitting elements of recent organic EL displays by having a light reduction rate of 95% or more at a wavelength of 390 nm to 410 nm. On the other hand, with respect to the wavelength of 420 nm to 450 nm in the visible light region, it is required to minimize the light reduction rate in order to ensure the display brightness of the organic EL display. It is possible to suppress the light drop rate at the wavelength of , and the display brightness of the organic EL display is not adversely affected.

Further, the hard coat film of the present invention was further irradiated with ultraviolet light for 100 hours under an environment of 63° C. temperature and 50% relative humidity with an irradiance of 500 W/m ² (light resistance test). It is characterized in that the absolute value of the change rate (Δ%) of the light transmittance at each wavelength satisfies the following conditions (Q) to (AA).
(Q) The absolute value of the rate of change in light transmittance at a wavelength of 350 nm is 1.0% or less.
(R) The absolute value of the rate of change in light transmittance at a wavelength of 360 nm is 1.0% or less.
(S) The absolute value of the rate of change in light transmittance at a wavelength of 370 nm is 1.0% or less.
(T) The absolute value of the rate of change in light transmittance at a wavelength of 380 nm is 1.0% or less.
(U) The absolute value of the rate of change in light transmittance at a wavelength of 390 nm is 5.0% or less.
(V) The absolute value of the rate of change in light transmittance at a wavelength of 400 nm is 10.0% or less.
(W) The absolute value of the rate of change in light transmittance at a wavelength of 410 nm is 30.0% or less.
(X) The absolute value of the rate of change in light transmittance at a wavelength of 420 nm is 30.0% or less.
(Y) The absolute value of the rate of change in light transmittance at a wavelength of 430 nm is 10.0% or less.
(Z) The absolute value of the rate of change in light transmittance at a wavelength of 440 nm is 5.0% or less.
(AA) The absolute value of the rate of change in light transmittance at a wavelength of 450 nm is 5.0% or less.

Here, the change rate (Δ%) of the light transmittance at each wavelength is calculated by the following formula 2.
Formula 2) Rate of change in light transmittance at each wavelength (Δ%) = Transmittance at the wavelength after the light resistance test of the hard coat film - Transmittance at the wavelength before the light resistance test of the hard coat film

The hard coat film of the present invention is provided with a hard coat layer made of an ultraviolet curable resin containing the above-mentioned ultraviolet absorber and dye, and the optical properties of the present invention, that is, the above conditions (Q) to (AA) are maintained even after the light resistance test. ) is a hard coat film that satisfies

The transmittance of each wavelength mentioned above contributes to the protection of the wavelengths of 350 nm to 400 nm, which cause damage such as deterioration of some polymers and fading and discoloration of dyes, and the light-emitting elements of recent organic EL displays. It is necessary to maintain its performance even after a light resistance test at a wavelength of 390 nm to 410 nm. Since it can be suppressed, deterioration of the display of the organic EL display can be suppressed. In addition, even at a wavelength of 420 nm to 450 nm in the visible light region, it is necessary to maintain the performance even after the light resistance test. The display brightness of the organic EL display can be maintained.

As described above in detail, according to the present invention, a cycloolefin polymer film is used as a base material, and even for such a base material having few polar groups and poor adhesion, it is easy to provide a polarizer on the base film. A hard coat film having excellent adhesion (initial adhesion and light resistance adhesion) to the adhesive layer and hard coat layer can be obtained. Further, according to the present invention, the easy-adhesion layer provided on the base film has good solvent resistance against hydrocarbon solvents, and a hard coat paint containing a hydrocarbon-based solvent is applied on the easy-adhesion layer. It is possible to provide a hard coat film capable of obtaining a good coating appearance even when directly coated. In addition, according to the present invention, when used as a protective film on the surface of an organic EL display, the display color and brightness of the organic EL display are not adversely affected, and the durability (light resistance) of the light emitting element of the organic EL display is improved. It is possible to provide a hard coat film capable of improving the display quality of an organic EL display and suppressing display deterioration. In particular, the hard coat film of the present invention is suitable when a thin cycloolefin polymer film is used as a substrate.

EXAMPLES Next, the embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.
In the descriptions below, "parts" means parts by mass unless otherwise stated, and "%" means % by mass unless otherwise stated.

(Example 1)
[Preparation of coating solution for forming easy-adhesion layer]
100 parts of an acrylate-based UV-curable resin coating (Luxidia CH-C-1623 (trade name); manufactured by DIC Corporation) containing silica fine particles (average particle size: 100 nm) of the present invention is added to methyl ethyl ketone/1-methoxy-2 - Diluted with propanol = 50/50 (parts by weight) to prepare an easy-adhesion layer-forming coating solution (hereinafter referred to as "easy-adhesion layer coating material") having a solid content concentration of 10%.

[Preparation of Coating Solution for Forming Hard Coat Layer]
Acrylate-based UV-curable resin coating containing the benzotriazole-based UV absorber of the present invention (HFC-UVA-1 (trade name); manufactured by Harima Kasei Co., Ltd. Maximum absorption wavelength of benzotriazole-based UV absorber: 370 nm) 85 parts as a main component, 3.5 parts of Irgacure 184 (photopolymerization initiator, manufactured by BASF), 0.5 parts of a surface modifier (Ftergent 681; manufactured by Neos Co., Ltd.), and the hydroxyphenyl triazine of the present invention Ultraviolet absorber (Tinuvin 477 (trade name); manufactured by BASF Japan Ltd. Maximum absorption wavelength: 356 nm) 10 parts, cyanine dye of the present invention (NK-9994 (trade name); manufactured by Hayashibara Co., Ltd. Maximum absorption wavelength ; 405 nm) 1.0 part, diluted with toluene/methyl ethyl ketone/propylene glycol monomethyl ether acetate = 15/35/50 (parts by weight), and coated for forming a hard coat layer with a final solid content concentration of 30% A liquid (hereinafter referred to as "hard coat paint") was prepared.

[Preparation of hard coat film]
On one side of Zeonor Film ZD12 (manufactured by Nippon Zeon Co., Ltd.) with a thickness of 26 μm as a cycloolefin polymer film, the above paint for easy adhesion layer is applied using a bar coater, and dried in a drying oven at 60 ° C. for 1 minute. It was dried with hot air and solidified to form an easily adhesive layer coating film having a coating thickness of 0.2 μm. Using a UV irradiation device set at a height of 60 mm from the coating surface, this was cured by irradiating UV rays at a dose of 50 mJ/cm ² to form an easy-adhesion layer to obtain an easy-adhesion layer-coated film.
Next, on the easy adhesion layer of this easy adhesion layer-coated film, the above hard coat paint is applied using a bar coater and dried with hot air in a drying oven at 80° C. for 1 minute to obtain a coating thickness of 4. A coating layer of 5 μm was formed. The hard coat film of Example 1 was produced by curing this by irradiating with UV rays at a dose of 100 mJ/cm ² using a UV irradiator set at a height of 60 mm from the coating surface.

(Example 2)
A hard coat film of Example 2 was produced in the same manner as in Example 1, except that Zeonor Film ZF16 (manufactured by Nippon Zeon Co., Ltd.) having a thickness of 50 μm was used as the cycloolefin polymer film of Example 1.

(Example 3)
A hard coat film of Example 3 was produced in the same manner as in Example 1, except that Zeonor Film ZF12 (manufactured by Nippon Zeon Co., Ltd.) having a thickness of 13 μm was used as the cycloolefin polymer film of Example 1.

(Example 4)
[Preparation of paint for easy adhesion layer]
100 parts of an acrylate-based UV-curable resin paint (Beamset NOP-102 (trade name); manufactured by Arakawa Chemical Industries, Ltd.) containing silica fine particles (average particle size: 100 nm) of the present invention, 1-methoxy-2- It was diluted with propanol to prepare an easy-adhesion layer paint having a solid content concentration of 10%.

[Preparation of hard coat film]
A hard coat film of Example 4 was produced in the same manner as in Example 1, except that the easy-adhesion layer coating composition having the above composition was used.

(Example 5)
[Preparation of paint for hard coating]
Acrylate-based UV-curable resin (NK Ester A-9550 (trade name); manufactured by Shin-Nakamura Chemical Co., Ltd.) is used as the main agent, and the benzotriazole-based UV absorber of the present invention (Tinuvin 970 (trade name); BASF Japan 10 parts of maximum absorption wavelength; part, the hydroxyphenyltriazine-based ultraviolet absorber of the present invention (Tinuvin 477 (trade name); manufactured by BASF Japan Ltd.) 10 parts, the cyanine dye of the present invention (NK-9994 (trade name); manufactured by Hayashibara Co., Ltd.) 1 0 part and diluted with toluene/methyl ethyl ketone/propylene glycol monomethyl ether acetate=15/35/50 (parts by weight) to prepare a hard coat paint having a final solid concentration of 30%.

[Preparation of hard coat film]
A hard coat film of Example 5 was produced in the same manner as in Example 1, except that the hard coat paint having the above composition was used.

(Example 6)
[Preparation of paint for hard coating]
Based on 74 parts of an acrylate-based UV-curable resin (NK Ester A-9550 (trade name); manufactured by Shin-Nakamura Chemical Co., Ltd.), the benzotriazole-based UV absorber of the present invention (ADEK STAB LA-29 (trade name) ; manufactured by ADEKA Corporation. Maximum absorption wavelength: 350 nm) 10 parts, Irgacure 184 (photopolymerization initiator, manufactured by BASF) 3.5 parts, surface modifier (Ftergent 681; manufactured by Neos Co., Ltd.) at 0 .5 parts, the hydroxyphenyltriazine-based ultraviolet absorber of the present invention (Tinuvin 477 (trade name); manufactured by BASF Japan Co., Ltd.) 10 parts, the cyanine dye of the present invention (NK-9994 (trade name); manufactured by Hayashibara Co., Ltd. ) and diluted with toluene/methyl ethyl ketone/propylene glycol monomethyl ether acetate = 15/35/50 (parts by weight) to prepare a hard coat paint having a final solid concentration of 30%.

[Preparation of hard coat film]
A hard coat film of Example 6 was produced in the same manner as in Example 1, except that the hard coat paint having the above composition was used.

(Example 7)
The cyanine dye of the present invention (NK-9994 (trade name); manufactured by Hayashibara Co., Ltd.) in the hard coat paint in Example 1 was replaced with the cyanine dye of the present invention (NK-10490 (trade name); manufactured by Hayashibara Co., Ltd.). Maximum absorption wavelength; A hard coat film was produced.

(Example 8)
A hard coat film of Example 8 was produced in the same manner as in Example 1, except that the coating thickness of the easy adhesion layer in Example 1 was changed to 1.8 μm.

(Example 9)
A hard coat film of Example 9 was produced in the same manner as in Example 1, except that the coating thickness of the hard coat layer in Example 1 was changed to 8.0 μm.

(Comparative example 1)
[Preparation of paint for hard coating]
Acrylate UV curable resin (NK Ester A-9550 (trade name); manufactured by Shin Nakamura Chemical Co., Ltd.) 96 parts as the main agent, Irgacure 184 (photopolymerization initiator, manufactured by BASF) 3.5 parts, surface 0.5 part of a modifier (Futergent 681; manufactured by Neos Co., Ltd.) was mixed and diluted with toluene/methyl ethyl ketone/propylene glycol monomethyl ether acetate = 15/35/50 (parts by weight) to obtain a final solid content. A hard coat paint having a concentration of 30% was prepared.

[Preparation of hard coat film]
A hard coat film of Comparative Example 1 was produced in the same manner as in Example 1, except that the hard coat paint having the above composition was used.

(Comparative example 2)
[Preparation of paint for hard coating]
Based on 75 parts of an acrylate-based UV-curable resin (NK Ester A-9550 (trade name); manufactured by Shin-Nakamura Chemical Co., Ltd.), a dihydroxybenzophenone-based UV absorber (Uvinul 3050 (trade name); BASF Japan Co., Ltd. ) made.Maximum absorption wavelength: 345 nm) 10 parts, Irgacure 184 (photopolymerization initiator, manufactured by BASF) 3.5 parts, surface modifier (Ftergent 681; manufactured by Neos Co., Ltd.) 0.5 parts, Hydroxyphenyltriazine-based ultraviolet absorber (Tinuvin477 (trade name); manufactured by BASF Japan Co., Ltd.) 10 parts, cyanine dye (NK-9994 (trade name); manufactured by Hayashibara Co., Ltd.) 1.0 parts, and toluene /methyl ethyl ketone/propylene glycol monomethyl ether acetate = 15/35/50 (parts by weight) to prepare a hard coat paint having a final solid concentration of 30%.

[Preparation of hard coat film]
Comparative A hard coat film of Example 2 was produced.

(Comparative Example 3)
[Preparation of paint for hard coating]
80 parts of an acrylate-based UV-curable resin paint containing a benzotriazole-based UV absorber (HFC-UVA-1 (trade name); manufactured by Harima Kasei Co., Ltd.; the maximum absorption wavelength of the benzotriazole-based UV absorber; 370 nm). As a main agent, 3.5 parts of Irgacure 184 (photopolymerization initiator, manufactured by BASF), 0.5 parts of a surface modifier (Ftergent 681; manufactured by Neos Co., Ltd.), and a hydroxyphenyltriazine-based ultraviolet absorber (Tinuvin 477) (trade name); manufactured by BASF Japan Ltd. Maximum absorption wavelength: 356 nm) 10 parts, merocyanine dye (FDB-009 (trade name) manufactured by Yamada Chemical Industry Co., Ltd. maximum absorption wavelength: 402 nm) 6 parts and diluted with toluene/methyl ethyl ketone/propylene glycol monomethyl ether acetate=15/35/50 (parts by weight) to prepare a hard coat paint having a final solid concentration of 30%.

[Preparation of hard coat film]
A hard coat film of Comparative Example 3 was produced in the same manner as in Example 1, except that the hard coat paint having the above composition was used.

(Comparative Example 4)
[Preparation of paint for easy adhesion layer]
100 parts of an acrylate UV-curable resin paint (Luxidia EPS-1306 (trade name); manufactured by DIC Corporation) that does not contain silica fine particles is added to methyl ethyl ketone/1-methoxy-2-propanol = 50/50 (parts by weight). to prepare an easy-adhesion layer paint having a solid content concentration of 10%.

[Preparation of hard coat film]
A hard coat film of Comparative Example 4 was produced in the same manner as in Example 1, except that the easy-adhesion layer coating composition having the above composition was used.

(Comparative Example 5)
[Preparation of paint for easy adhesion layer]
100 parts of a polyolefin resin (Surflen P-1000 (trade name); manufactured by Mitsubishi Chemical Corporation), which is a thermoplastic resin, was diluted with butyl acetate to prepare an easy adhesion layer paint having a solid concentration of 10%.

[Preparation of hard coat film]
A hard coat film of Comparative Example 5 was produced in the same manner as in Example 1, except that the easy-adhesion layer coating composition having the above composition was used.

<Evaluation>
The hard coat films of Examples and Comparative Examples produced as described above were evaluated for the following items, and the results are summarized in Tables 1, 2 and 3.

<Thickness of coating film>
The formed thicknesses of the coating films of the easy-adhesion layer and the hard coat layer were measured using a Thin-Film Analyzer F20 (trade name) (manufactured by FILMETRICS).

<Adhesion (initial adhesion)>
Adhesion was evaluated by a checkerboard peeling test according to the crosscut method of JIS-K5600-5-6. Specifically, for each hard coat film produced in Examples and Comparative Examples, a cutter knife was applied to the hard coat layer formation surface under a normal environment, that is, under a constant temperature and humidity environment (25 ° C., 50% RH). 11 vertical and 11 horizontal incisions were made in a grid pattern at intervals of 1 mm to cut a total of 100 squares, and adhesive tape No. 252 manufactured by Sekisui Chemical Co., Ltd. was pasted thereon. After uniformly pressing with a spatula, the layer was peeled off in the direction of 180 degrees, and the remaining number of hard coat layers was defined as the remaining rate (%).
For the initial adhesion of the easy-adhesion layer, the peel test was performed on the easy-adhesion layer-coated film.

<Solvent resistance>
Solvent resistance was evaluated by dripping toluene onto the surface of the cycloolefin polymer film alone used in Examples and Comparative Examples, or each easily adhesive layer-coated film prepared in Examples and Comparative Examples so that the diameter was about 10 mm. After 3 minutes had elapsed, the surface was wiped off with gauze, and the appearance of the surface on which the chemical had been dropped was visually evaluated. ○ The solvent resistance of the evaluated product was judged to be good.
○: No change in the appearance of the chemical dripping surface ×: Change in the appearance of the chemical dripping surface

<b* value>
The b* value was measured for each hard coat film produced in Examples and Comparative Examples using a spectrophotometer U-3310 manufactured by Hitachi High-Technologies Corporation.

<Light transmittance at each wavelength>
The light transmittance of the hard coat film at each wavelength was measured using a spectrophotometer U-3310 manufactured by Hitachi High-Technologies Corporation. The measurement was performed at a wavelength range of 250 nm to 800 nm and a scan speed of 600 nm/min. After detecting the light transmittance at each wavelength, the "light reduction rate (%) at each wavelength" shown in Equation 1 below was calculated. When the transmittance of the cycloolefin polymer film alone at the wavelength was 0.0%, the light reduction rate at each wavelength was taken as 100%.
Formula 1) Light reduction rate (%) at each wavelength = (Transmittance of the cycloolefin polymer film alone at the wavelength - Transmittance of the hard coat film at the wavelength) / (Transmittance of the cycloolefin polymer film alone at the wavelength)

<Light resistance test>
An accelerated lightfastness test (according to JIS B 7751:2007, under the following conditions) was performed on each hard coat film produced in Examples and Comparative Examples using an ultraviolet carbon fade meter.
Light source: UV carbon arc lamp Temperature: 63°C
Relative humidity: 50%
Irradiance: 500W/ ^m2
Radiation time: 100 hours Period and time of rainfall: No setting

<Adhesion after light resistance test>
Adhesion after the light resistance test was performed by the same cross-cut test method as for the above adhesion, and the remaining number of hard coat layers was defined as the residual rate (%).
The adhesion of the easy-adhesion layer after the light resistance test is determined by the peeling test of the hard coat film in which a hard coat layer is provided on the easy-adhesion layer. Delamination of the layer was determined.

<Rate of change in light transmittance at each wavelength>
The rate of change in light transmittance at each wavelength of the hard coat film after the light resistance test was measured under the same conditions using the same spectrophotometer U-3310 as the light transmittance at each wavelength above. After detecting the light transmittance, the "rate of change in light transmittance (Δ%) at each wavelength" shown in Equation 2 below was calculated. In addition, when the rate of change was negative, it was evaluated as an absolute value.
Formula 2) Change rate of light transmittance at each wavelength (Δ%) = Transmittance at the wavelength after the light resistance test of the hard coat film - Transmittance at the wavelength before the light resistance test of the hard coat film

As is clear from the results in Table 1 above, the hard coat films of Examples 1 to 9 and Comparative Examples 1 to 3 of the present invention using an easy-adhesion layer made of an ultraviolet curable resin containing silica fine particles have excellent initial adhesion. and light fastness adhesion (adhesion after the light resistance test). By using an easy-adhesion layer made of an ultraviolet curable resin containing silica fine particles, the adhesion (initial A hard coat layer having excellent adhesion and light resistance) can be formed. That is, according to the present invention, a cycloolefin polymer-based film is used as a substrate, and an easy-adhesion layer and a hard coat layer are provided on the substrate film even for such a substrate having few polar groups and poor adhesion. It is possible to obtain a hard coat film excellent in adhesion (initial adhesion and light resistance adhesion) with.
In Comparative Example 4 in Table 1, the easy adhesion layer residual rate, the residual rate after the light resistance test, the hard coat layer residual rate, and the residual rate after the light resistance test are all 0%. This means that peeling occurs at the easy-adhesion layer. When peeling occurs at the easy-adhesion layer, the hard coat layer thereon is also peeled off together.

Table 1 above shows the evaluation results of the solvent resistance of the cycloolefin polymer film and the easy-adhesion layer. Hydrocarbon solvents such as toluene are good solvents for the UV absorber and dye used in the hard coat layer composed of the UV curable resin containing the UV absorber and dye of the present invention. However, the cycloolefin polymer film used in the present invention has poor solvent resistance to hydrocarbon solvents such as toluene and is easily dissolved. Direct coating causes chemical cracks, making it difficult to obtain a good coating appearance. Therefore, the easy-adhesion layer made of an ultraviolet curable resin containing inorganic fine particles (silica fine particles in the examples) of the present invention has good solvent resistance against hydrocarbon solvents such as toluene. Even when a solvent-containing hard coat paint is directly applied, a good coating appearance can be obtained. However, in the case of Comparative Example 5 using an easy-adhesion layer made of a thermoplastic resin, unlike the easy-adhesion layer made of an ultraviolet-curable resin containing inorganic fine particles of the present invention, the resistance to hydrocarbon solvents such as toluene was Since the solvent resistance cannot be improved, when a hard coat paint containing a hydrocarbon solvent such as toluene is applied, a good coating appearance cannot be obtained, making it difficult to produce a hard coat film. Met.

Further, as is clear from the results in Table 2 above, the hard coat film of the present invention is provided with a hard coat layer made of an ultraviolet curable resin containing the above-described ultraviolet absorber and dye, and has the predetermined optical properties of the present invention. , that is, a hard coat film that satisfies the above conditions (E) to (P). As a result, the hard coat film of the present invention suppresses the b* value, which is an index of yellowness, and does not adversely affect the display color of the organic EL display, and causes deterioration of some polymers, fading and discoloration of pigments, etc. 95% or more can be obtained at a wavelength of 350 nm to 400 nm, which causes damage, and damage such as deterioration of some polymers and fading and discoloration of pigments can be suppressed. Furthermore, in order to improve the durability (light resistance) of the light-emitting elements of recent organic EL displays, it is required to sufficiently reduce the light transmittance of 390 nm to 410 nm in order to protect the light-emitting elements. The hard coat film of the invention can obtain a light reduction rate of 95% or more at a wavelength of 390 nm to 410 nm, and can improve the durability (light resistance) of light emitting elements of recent organic EL displays. On the other hand, with respect to the wavelength of 420 nm to 450 nm in the visible light region, it is required to minimize the light reduction rate in order to ensure the display brightness of the organic EL display. It is possible to suppress the light drop rate at the wavelength of , and the display brightness of the organic EL display is not adversely affected.

In addition, as is clear from the results in Table 3 above, the hard coat film of the present invention was provided with a hard coat layer made of an ultraviolet curable resin containing the above-mentioned ultraviolet absorber and dye, and even after the light resistance test, the hard coat layer of the present invention remained. is a hard coat film that satisfies the optical properties of the above conditions (Q) to (AA).
The transmittance of each wavelength mentioned above contributes to the protection of the wavelengths of 350 nm to 400 nm, which cause damage such as deterioration of some polymers and fading and discoloration of dyes, and the light-emitting elements of recent organic EL displays. It is necessary to maintain its performance even after a light resistance test at a wavelength of 390 nm to 410 nm. Since it can be suppressed, deterioration of the display of the organic EL display can be suppressed. In addition, even at a wavelength of 420 nm to 450 nm in the visible light region, it is necessary to maintain the performance even after the light resistance test. The display brightness of the organic EL display can be maintained.

On the other hand, in Comparative Example 1 using a hard coat layer made of an ultraviolet curable resin containing neither an ultraviolet absorber nor a dye, the transmittance of 380 nm to 410 nm cannot be reduced, so the organic EL display There is a problem that the display of Further, in Comparative Example 2 using a different type of ultraviolet absorber from the ultraviolet absorber preferably used in the present invention, the light reduction rate at each wavelength is insufficient, and the light transmittance at each wavelength after the light resistance test The rate of change in is large, and there are problems that the display of the organic EL display deteriorates and that the durability (light resistance) of the light-emitting element cannot be improved. Furthermore, in Comparative Example 3 using a different type of dye from the dye preferably used in the present invention, although there is no problem in the light reduction rate at each wavelength, the b* value, which is an index of yellowness, is high. There is a problem that the color of the display is adversely affected, and the rate of change in light transmittance at each wavelength after the light resistance test is extremely large, and there is a problem that the durability (light resistance) of the light emitting element of the organic EL display cannot be improved. be. On the other hand, in Comparative Example 4 in which the easy-adhesion layer made of the ultraviolet curable resin containing inorganic fine particles of the present invention was not used (that is, the ultraviolet curable resin containing no inorganic fine particles), the adhesion to the substrate film was poor ( See Table 1 above), there is a problem that the hard coat layer made of an ultraviolet-curing resin containing an ultraviolet absorber and a dye is missing, making it impossible to protect the organic EL display.

Claims (4)

A hard coat layer containing an ultraviolet curable resin, an ultraviolet absorber and a dye is laminated on at least one side of a cycloolefin polymer film having a thickness of 50 μm or less via an easy-adhesion layer made of an ultraviolet curable resin containing inorganic fine particles. is,
The ultraviolet absorber is a combination of a benzotriazole-based ultraviolet absorber and a hydroxyphenyltriazine-based ultraviolet absorber,
The maximum absorption wavelength (λmax) of the ultraviolet absorber comprising the combination of the benzotriazole-based ultraviolet absorber and the hydroxyphenyltriazine-based ultraviolet absorber is in the range of 350 nm to 380 nm, and the maximum absorption wavelength (λmax) of the dye. is in the range of 395 nm to 415 nm,
A hard coat film characterized by satisfying the following conditions (A) to (D).
(A) The thickness of the easy-adhesion layer is in the range of 0.1 to 2.0 μm.
(B) The thickness of the hard coat layer is in the range of 1.0 to 10.0 μm.
(C) The residual rate of the hard coat layer and the easily adhesive layer measured by the cross-cut method of JIS-K5600-5-6 of the hard coat film is 100%.
(D) The hard coat film was irradiated with ultraviolet rays for 100 hours (light resistance test) at an irradiance of 500 W/m ² in an environment of a temperature of 63 ° C. and a relative humidity of 50%, and then JIS-K5600-5- Both the residual rates of the hard coat layer and the easily adhesive layer measured by the cross-cut method of No. 6 are 100%. The hard coat film further satisfies the following condition (E), and the light reduction rate (%) at each wavelength calculated by the following formula 1 satisfies the following conditions (F) to (P). 1. The hard coat film according to 1.
(E) The b* value is 7.0 or less.
Formula 1) Light reduction rate (%) at each wavelength = (transmittance of the cycloolefin polymer film alone at the wavelength - transmittance of the hard coat film at the wavelength) / cycloolefin polymer film alone at the wavelength The light transmittance (F) of 350 nm wavelength is 95.0% or more.
(G) The light reduction rate at a wavelength of 360 nm is 95.0% or more.
(H) The light reduction rate at a wavelength of 370 nm is 95.0% or more.
(I) The light reduction rate at a wavelength of 380 nm is 95.0% or more.
(J) The light reduction rate at a wavelength of 390 nm is 95.0% or more.
(K) The light reduction rate at a wavelength of 400 nm is 95.0% or more.
(L) The light reduction rate at a wavelength of 410 nm is 95.0% or more.
(M) Light reduction rate at a wavelength of 420 nm is 75.0% or less.
(N) The light reduction rate at a wavelength of 430 nm is 30.0% or less.
(O) Light reduction rate at 440 nm wavelength is 7.0% or less.
(P) The reduction rate of light at a wavelength of 450 nm is 2.0% or less. For the hard coat film, in an environment with a temperature of 63 ° C. and a relative humidity of 50%, an irradiance of 500 W / m ² , and after irradiating ultraviolet rays for 100 hours (light resistance test), each wavelength calculated by the following formula 2 3. The hard coat film according to claim 1, wherein the absolute value of the rate of change (Δ%) of the light transmittance at the time satisfies the following conditions (Q) to (AA).
Formula 2) Change rate of light transmittance at each wavelength (Δ%) = Transmittance at the wavelength after the light resistance test of the hard coat film - Transmittance at the wavelength before the light resistance test of the hard coat film (Q ) The absolute value of the rate of change in light transmittance at a wavelength of 350 nm is 1.0% or less.
(R) The absolute value of the rate of change in light transmittance at a wavelength of 360 nm is 1.0% or less.
(S) The absolute value of the rate of change in light transmittance at a wavelength of 370 nm is 1.0% or less.
(T) The absolute value of the rate of change in light transmittance at a wavelength of 380 nm is 1.0% or less.
(U) The absolute value of the rate of change in light transmittance at a wavelength of 390 nm is 5.0% or less.
(V) The absolute value of the rate of change in light transmittance at a wavelength of 400 nm is 10.0% or less.
(W) The absolute value of the rate of change in light transmittance at a wavelength of 410 nm is 30.0% or less.
(X) The absolute value of the rate of change in light transmittance at a wavelength of 420 nm is 30.0% or less.
(Y) The absolute value of the rate of change in light transmittance at a wavelength of 430 nm is 10.0% or less.
(Z) The absolute value of the rate of change in light transmittance at a wavelength of 440 nm is 5.0% or less.
(AA) The absolute value of the rate of change in light transmittance at a wavelength of 450 nm is 5.0% or less. 4. The hard coat film according to claim 2, which has a b* value of 2.8 or more and 7.0 or less.