WO2014185345A1

WO2014185345A1 - Method for producing hard-coat film

Info

Publication number: WO2014185345A1
Application number: PCT/JP2014/062441
Authority: WO
Inventors: 啓史別宮
Original assignee: コニカミノルタ株式会社
Priority date: 2013-05-14
Filing date: 2014-05-09
Publication date: 2014-11-20

Abstract

This method for producing a hard-coat film involves producing the film by: subjecting a hard-coat film, which is obtained by forming a hard-coat layer containing a hard-coat resin and a leveling agent on a resin film, to irradiation with light having a wavelength shorter than 200nm in a manner such that the cumulative amount of light having a wavelength shorter than 200nm is 50 mJ/cm² to 5000 mJ/cm², inclusive; and as a result, breaking down the leveling agent in the surface layer of the hard-coat layer, and causing the hard-coat resin in the surface layer of the hard-coat layer to absorb at least some of the light having a wavelength shorter than 200nm.

Description

Method for producing hard coat film

The present invention relates to a method for producing a hard coat film.

A hard coat film is used as a base for forming a conductive film or an antireflection film. In order to recoat the hard coat film, it is necessary to reduce the contact angle with water of the hard coat film so as not to repel the coating liquid mainly composed of water and alcohol. In general, after saponification to reduce the contact angle with water, drying, winding, and subsequent coating are required, which increases the cost. Therefore, a technique for reducing the contact angle at low cost by using corona treatment, UV treatment, plasma treatment, or the like is also used (see Patent Document 1).

Moreover, the hard coat film is used on the outermost surface of the display device, and a touch panel or a cover glass is bonded to the surface of the hard coat film in a tablet terminal or a smartphone. Here too, a low contact angle of the hard coat film is required for bonding. When a hard coat film is used in a display device, the hard coat film is made into a polarizing plate in the manufacturing process of the display device. Therefore, a hard coat film whose contact angle has been reduced in advance by conventional corona treatment, UV treatment, plasma treatment, etc. is used. In such a case, there arises a problem that the contact angle has returned to its original value due to a change with time.

The contact angle is greatly affected by the leveling agent oriented on the surface of the hard coat. Since the leveling agent is essential for ensuring the applicability (control of surface roughness etc.) of the hard coat, it is difficult to change to another material in order to reduce the contact angle. In view of this, a technique of incorporating hydrophilic fine particles has been proposed as means for reducing the contact angle (see Patent Document 2).

JP 2007-161857 A JP 2001-272503 A

However, it is not preferable to add a new material such as hydrophilic fine particles only for the purpose of lowering the contact angle of the hard coat because it causes an increase in cost and a decrease in transparency.

In view of the above circumstances, an object of the present invention is to provide a method for producing a hard coat film that realizes a continuous low contact angle of the hard coat film without adding a new material.

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

1. A hard coat film having a hard coat layer containing a hard coat resin and a leveling agent formed on a resin film is irradiated with light containing light having a wavelength shorter than 200 nm, and an integrated light quantity of light having a wavelength shorter than 200 nm is 50 mJ / cm ² or more. By irradiating to 5000 mJ / cm ² or less, the leveling agent on the surface layer of the hard coat layer is decomposed, and the hard coat resin on the surface layer of the hard coat layer has at least light with a wavelength shorter than 200 nm. A method for producing a hard coat film, wherein a part of the hard coat film is absorbed.

2. ^{2. The} method for producing a hard coat film according to 1 above, wherein an integrated light amount of light having a wavelength shorter than 200 nm is 500 mJ / cm ² or more and 3500 mJ / cm ² or less.

3. 3. The method for producing a hard coat film according to 1 or 2, wherein the light containing light having a wavelength shorter than 200 nm is excimer light.

4. 4. The method for producing a hard coat film as described in 3 above, wherein a wavelength range of light contained in the excimer light is in a range of 100 nm to 230 nm.

5. 5. The method for producing a hard coat film as described in any one of 1 to 4 above, wherein the hard coat resin is an ultraviolet curable acrylate resin.

6. 6. The method for producing a hard coat film as described in any one of 1 to 5 above, wherein the leveling agent is a fluorine-siloxane graft compound.

7. 7. The method for producing a hard coat film as described in any one of 1 to 6 above, wherein the film is a cellulose ester film.

According to the present invention, by irradiating light wavelength to the hard coat layer contains a light shorter than 200nm, such wavelength is integrated quantity of light shorter light than 200nm becomes 50 mJ / cm ² or more 5000 mJ / cm ² or less, The leveling agent on the surface layer of the hard coat layer is decomposed, and the contact angle with water of the hard coat layer is lowered. Moreover, decomposition | disassembly of hard coat resin other than surface layer and the resin film used as a base material can be suppressed by absorbing at least a part of light having a wavelength shorter than 200 nm by the hard coat resin. Therefore, the continuous low contact angle of the hard coat film can be realized without adding new materials such as hydrophilic fine particles.

It is sectional drawing which shows the structure of the hard coat film of one Embodiment of this invention.

An embodiment of the present invention will be described below with reference to the drawings. In this specification, when the numerical range is expressed as A to B, the numerical value range includes the values of the lower limit A and the upper limit B.

[Configuration of hard coat film]
As shown in FIG. 1, the hard coat film 10 is obtained by forming a hard coat layer 12 including a hard coat resin 12 a and a leveling agent 12 b on a resin film 11. In the hard coat film 10, the leveling agent 12 b on the surface layer of the hard coat layer 12 is decomposed by irradiating the hard coat layer 12 with excimer light. The hard coat resin 12a on the surface layer of the hard coat layer 12 absorbs at least part of light having a wavelength shorter than 200 nm (absorbs excimer light), and the hard coat resin 12a and the resin film 11 other than the surface layer are not decomposed. Like that.

In this way, by irradiating the hard coat layer 12 with light containing light having a wavelength shorter than 200 nm so as to have a specific integrated light amount, the leveling agent 12b on the surface layer of the hard coat layer 12 is decomposed, and the hard coat layer 12 is decomposed. Excessive decomposition of the hard coat resin 12a and the resin film 11 can be suppressed while reducing the water contact angle. Therefore, the continuous low contact angle of the hard coat film 10 can be realized without adding new materials such as hydrophilic fine particles.

To achieve the above object of the present invention, it must be irradiated as wavelength wavelength light including light shorter than 200nm is integrated quantity of light shorter light than 200nm becomes 50 mJ / cm ² or more 5000 mJ / cm ² or less There, it is preferable that wavelength of the integrated light quantity of light shorter than 200nm is 500 mJ / cm ² or more 3500mJ / cm ² or less.

In addition, the integrated light quantity of light with a wavelength shorter than 200 nm can be measured by a C8026 illuminometer manufactured by Hamamatsu Photonics.

Here, specifically, excimer light is preferably used as light including light having a wavelength shorter than 200 nm, and the wavelength range of light included in the excimer light is preferably 100 to 230 nm.

The hard coat resin 12a is preferably an ultraviolet curable acrylate resin. As the leveling agent 12b, a fluorine-siloxane graft compound is preferable. As the film 11, a cellulose ester film is preferable.

[Details of each layer]
Hereinafter, the detail of each layer which comprises a hard coat film is demonstrated.

(Hard coat layer)
<Hard coat resin>
The hard coat resin is preferably an actinic ray curable resin from the viewpoint of excellent mechanical film strength (abrasion resistance, pencil hardness). That is, it is a layer mainly composed of a resin that is cured through a crosslinking reaction upon irradiation with active rays (also called active energy rays) such as ultraviolet rays and electron beams. As the actinic radiation curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and an actinic radiation curable resin layer is formed by curing by irradiation with actinic radiation such as ultraviolet rays or electron beams. The Typical examples of the actinic radiation curable resin include an ultraviolet curable resin and an electron beam curable resin, but a resin curable by ultraviolet irradiation is particularly excellent in mechanical film strength (abrasion resistance, pencil hardness). It is preferable from the point. Examples of the ultraviolet curable resin include an ultraviolet curable acrylate resin, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, and an ultraviolet curable resin. A curable epoxy resin or the like is preferably used, and among them, an ultraviolet curable acrylate resin or an ultraviolet curable urethane acrylate resin is preferable.

As the ultraviolet curable acrylate resin, polyfunctional acrylate is preferable. The polyfunctional acrylate is preferably selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate. Here, the polyfunctional acrylate is a compound having two or more acryloyloxy groups or methacryloyloxy groups in the molecule. Examples of the polyfunctional acrylate monomer include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate. , Tetramethylolmethane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tri / tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, glycerol triacrylate relay , Dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol di Methacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylol methane trimethacrylate, tetramethylol methane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pen Pentaerythritol tetramethacrylate, glycerol trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol penta methacrylate, dipentaerythritol hexa methacrylate, etc. isocyanurate derivatives of the active energy ray-curable are preferably exemplified.

Examples of the ultraviolet curable urethane acrylate resin include, for example, a polyurethane obtained by reacting an alcohol, a polyol, and / or a hydroxyl group-containing compound such as a hydroxyl group-containing acrylate and an isocyanate or, if necessary, these reactions. It is obtained by esterifying a compound with (meth) acrylic acid. More specifically, it is an addition reaction product of polyisocyanate and an acrylate having one hydroxy group and one or more (meth) acryloyl groups in one molecule. Examples of the polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4 ′. A compound having two isocyanate groups bonded to an alicyclic hydrocarbon such as aromatic isocyanate such as diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, norbornane diisocyanate, 1,4-cyclohexane diisocyanate (hereinafter referred to as alicyclic diisocyanate and A compound having two isocyanate groups bonded to an aliphatic hydrocarbon such as trimethylene diisocyanate and hexamethylene diisocyanate (hereinafter referred to as aliphatic diisocyanate). Abbreviated as sulphonate.) Phenylene diisocyanate, aromatic diisocyanates such as toluene diisocyanate, and aromatic aliphatic diisocyanates such as xylylene diisocyanate. These polyisocyanates can be used alone or in combination of two or more, preferably aliphatic diisocyanates and alicyclic diisocyanates. Of these, isophorone diisocyanate, norbornane diisocyanate, toluene diisocyanate and hexamethylene diisocyanate are preferred. Examples of the acrylate having one hydroxy group and one or more (meth) acryloyl groups in one molecule include trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol penta (meth). Examples include polyacrylates of polyvalent hydroxy group-containing compounds such as acrylates, adducts of these polyacrylates and ε-caprolactone, adducts of these polyacrylates and alkylene oxides, and epoxy acrylates. It is done. The acrylate having one hydroxy group and one or more (meth) acryloyl groups in one molecule can be used alone or in combination of two or more.

Further, among acrylates having one hydroxy group and one or more (meth) acryloyl groups in one molecule, acrylates having one hydroxy group and 3 to 5 (meth) acryloyl groups in one molecule are preferable. Examples of such acrylates include pentaerythritol triacrylate and dipentaerythritol pentaacrylate.

Specific products of the UV curable urethane acrylate resin include: Nippon Synthetic Chemical Industry Co., Ltd., Shikou UV-1700B, UV-6300B, UV-7600B, UV-7630B, UV-7630B, UV-7640B, Kyoeisha Chemical Co., Ltd. Company-made, UA-306H, UA-306T, UA-306I, UA-510H, Shin-Nakamura Chemical Co., Ltd., NK Oligo UA-1100H, NK Oligo UA-53H, NK Oligo UA-33H, NK Oligo UA-15HA Etc.

The viscosity of the actinic radiation curable resin can be measured using a B-type viscometer under the condition of 25 ° C. after stirring and mixing the resin with a disper. A monofunctional acrylate may also be used.

Monofunctional acrylates include isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isostearyl acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, lauryl acrylate, isooctyl acrylate, tetrahydrofurfuryl acrylate, behenyl Examples thereof include acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and cyclohexyl acrylate. Such monofunctional acrylates can be obtained from Nippon Kasei Kogyo Co., Ltd., Shin-Nakamura Chemical Co., Ltd., Osaka Organic Chemical Co., Ltd., etc.

When a monofunctional acrylate is used, it is preferably contained in the range of polyfunctional acrylate: monofunctional acrylate = 80: 20 to 98: 2 in terms of the mass ratio of polyfunctional acrylate to monofunctional acrylate.

<Photopolymerization initiator>
The hard coat layer preferably contains a photopolymerization initiator to accelerate the curing of the actinic radiation curable resin. The amount of the photopolymerization initiator is preferably contained in a mass ratio of photopolymerization initiator: active ray curable resin = 20: 100 to 0.01: 100. Specific examples of the photopolymerization initiator include alkylphenone series, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof, but are not particularly limited thereto. It is not something.

Commercially available products may be used as such photopolymerization initiators, and preferred examples include Irgacure 184, Irgacure 907, and Irgacure 651 manufactured by BASF Japan.

<Conductive agent>
The hard coat layer may contain a conductive agent in order to impart antistatic properties. Preferred conductive agents include metal oxide particles or π-conjugated conductive polymers. An ionic liquid is also preferably used as the conductive compound.

<Leveling agent>
The hard coat layer contains a leveling agent to smooth the surface. As the leveling agent, silicone surfactants, fluorine surfactants, anionic surfactants, fluorine-siloxane graft compounds, fluorine compounds, acrylic copolymers, and the like can be used. In general, since the leveling agent has high lipophilicity, when it is oriented on the surface of the hard coat layer, the contact angle with water becomes large.

Examples of the silicone surfactant include polyether-modified silicone, and the KF series manufactured by Shin-Etsu Chemical Co., Ltd. can be used. Examples of the acrylic copolymer include commercially available compounds such as BYK-350 and BYK-352 manufactured by BYK Japan. Examples of the fluorosurfactant include Megafac RS series, Megafac F-444 Megafac F-556 manufactured by DIC Corporation. The fluorine-siloxane graft compound refers to a copolymer compound obtained by grafting polysiloxane and / or organopolysiloxane containing siloxane and / or organosiloxane alone to at least a fluorine-based resin. Such a fluorine-siloxane graft compound can be prepared by a method as described in Examples described later. Alternatively, examples of commercially available products include ZX-022H, ZX-007C, ZX-049, and ZX-047-D manufactured by Fuji Chemical Industry Co., Ltd. Moreover, as a fluorine-type compound, Daikin Industries Ltd. OPTOOL DSX, OPTOOL DAC, etc. can be mentioned. These components are preferably added in the range of 0.005 parts by mass or more and 5 parts by mass or less with respect to the solid component in the hard coat composition.

<Ultraviolet absorber>
The hard coat layer may further contain an ultraviolet absorber. The content of the ultraviolet absorber is preferably in a mass ratio of ultraviolet absorber: hard coat resin = 0.01: 100 to 10: 100. Since the ultraviolet absorber absorbs ultraviolet rays of 400 nm or less, durability can be improved. In particular, the ultraviolet absorber preferably has a transmittance of 10% or less at a wavelength of 370 nm, more preferably 5% or less, and still more preferably 2% or less. Specific examples of the ultraviolet absorber are not particularly limited. For example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex salts, inorganic powders. Examples include the body.

More specifically, for example, 5-chloro-2- (3,5-di-sec-butyl-2-hydroxylphenyl) -2H-benzotriazole, (2-2H-benzotriazol-2-yl) -6 -(Linear and side chain dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone, and the like can be used. Commercially available products may be used. For example, TINUVIN such as TINUVIN 109, TINUVIN 171, TINUVIN 234, TINUVIN 326, TINUVIN 327, and TINUVIN 328 manufactured by BASF Japan Ltd. can be preferably used.

Preferably used ultraviolet absorbers are benzotriazole ultraviolet absorbers, benzophenone ultraviolet absorbers, and triazine ultraviolet absorbers, and particularly preferably benzotriazole ultraviolet absorbers and benzophenone ultraviolet absorbers.

In addition, a discotic compound such as a compound having a 1,3,5 triazine ring is also preferably used as an ultraviolet absorber. As the UV absorber, a polymer UV absorber can be preferably used, and a polymer type UV absorber is particularly preferably used.

As the benzotriazole ultraviolet absorber, TINUVIN 109 (octyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazole-2-) manufactured by BASF Japan Ltd., which is a commercial product, is available. Yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate), TINUVIN 928 (2 -(2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol) and the like can be used. As the triazine-based ultraviolet absorber, commercially available TINUVIN 400 (2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -manufactured by BASF Japan Ltd.- Reaction product of 5-hydroxyphenyl and oxirane), TINUVIN 460 (2,4-bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3-5 Triazine), TINUVIN 405 (2- (2,4-dihydroxyphenyl) -4,6-bis- (2,4-dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidic acid ester Reaction products) and the like.

<solvent>
The hard coat layer is a component that forms the above-described hard coat layer, diluted with a solvent that swells or partially dissolves the film as a base material, and is applied onto the film by the following method as a hard coat layer composition. It is preferable to provide a hard coat layer by drying and curing.

As the solvent, ketones (methyl ethyl ketone, acetone, etc.) and / or acetate esters (methyl acetate, ethyl acetate, butyl acetate, etc.), alcohols (ethanol, methanol), propylene glycol monomethyl ether, cyclohexanone, methyl isobutyl ketone, etc. are preferable. The coating amount of the hard coat layer is suitably in the range of 0.1 to 40 μm as wet film thickness, and preferably in the range of 0.5 to 30 μm. The dry film thickness is in the range of an average film thickness of 0.01 to 20 μm, preferably in the range of 0.5 to 10 μm. More preferably, it is in the range of 0.5 to 5 μm.

As a method for applying the hard coat layer, known methods such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, and an ink jet method can be used.

<Hard coat layer forming method>
After applying the hard coat layer composition, it may be dried and cured by irradiation with active rays (also referred to as UV curing treatment), and if necessary, heat treatment may be performed after the UV curing treatment. The heat treatment temperature after the UV curing treatment is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and particularly preferably 120 ° C. or higher. By performing the heat treatment after the UV curing treatment at such a high temperature, a hard coat layer having excellent film strength can be obtained.

Drying is preferably performed by high-temperature treatment at a temperature of 90 ° C. or higher in the rate of drying section. More preferably, the temperature in the decreasing rate drying section is 90 ° C. or higher and 125 ° C. or lower.

In general, it is known that the drying process changes from a constant state to a gradually decreasing state when drying starts. The decreasing section is called the decreasing rate drying section. In the constant rate drying section, the amount of heat flowing in is all consumed for solvent evaporation on the coating film surface, and when the solvent on the coating film surface decreases, the evaporation surface moves from the surface to the inside and enters the decreasing rate drying section. Thereafter, the temperature of the coating film surface rises and approaches the hot air temperature, so that the temperature of the actinic radiation curable resin composition rises, the resin viscosity decreases, and the fluidity increases.

As a light source for UV curing treatment, any light source that generates ultraviolet rays can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.

Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually in the range of 50 to 1000 mJ / cm ² , preferably in the range of 50 to 300 mJ / cm ² . In the UV curing treatment, oxygen removal (for example, replacement with an inert gas such as nitrogen purge) can be performed to prevent reaction inhibition by oxygen. The cured state of the surface can be controlled by adjusting the removal amount of the oxygen concentration. When irradiating actinic radiation, it is preferably performed while applying tension in the film transport direction, and more preferably while applying tension in the width direction. The tension to be applied is preferably 30 to 300 N / m. The method for applying the tension is not particularly limited, and the tension may be applied in the transport direction on the back roller, or the tension may be applied in the width direction or the biaxial direction by a tenter. Thereby, a film having further excellent flatness can be obtained.

Next, after the hard coat layer is cured, light including light having a wavelength shorter than 200 nm is irradiated. For example, an excimer light source or a low-pressure mercury lamp can be used. Light having a wavelength shorter than 200 nm decomposes the leveling agent on the surface layer of the hard coat layer, and at least a part of light having a wavelength shorter than 200 nm is absorbed by the hard coat resin on the surface layer of the hard coat layer. As a result, the contact angle with water of the hard coat layer can be lowered, and decomposition of the hard coat resin other than the surface layer and the resin film serving as the substrate can be suppressed. This reduction in contact angle is considered to be achieved by the decomposition of the leveling agent, and therefore hardly changes with time.

When irradiating excimer light as light containing light having a wavelength shorter than 200 nm, it is preferable that the wavelength range of the light contained in the excimer light be in the range of 100 nm to 230 nm. This is because if the wavelength is too short, the hard coat resin is deteriorated, and if the wavelength is too long, the leveling agent cannot be decomposed. As the light source having such a wavelength, for example, a xenon lamp can be used.

Xe used in a xenon lamp is a rare gas, and since the atoms of the rare gas are chemically bonded to form no molecule, it is called an inert gas. However, rare gas atoms (excited atoms) that have gained energy by discharge or the like can be combined with other atoms to form molecules. For Xe,
e + Xe → e + Xe ^*
Xe ^* + Xe + Xe → Xe ₂ ^* + Xe
Thus, when the excited excimer molecule Xe ₂ ^* transitions to the ground state, excimer light of 172 nm is emitted.

In order to obtain excimer light, a method using dielectric barrier discharge is known. Dielectric barrier discharge refers to lightning generated in a gas space by arranging a gas space between both electrodes via a dielectric (transparent quartz in the case of an excimer lamp) and applying a high frequency high voltage of several tens of kHz to the electrode. It is a similar very thin discharge called micro-discharge.

In addition to the dielectric barrier discharge, electrodeless electric field discharge is also known as a method for efficiently obtaining excimer light. The electrodeless field discharge is a discharge due to capacitive coupling, and is also called an RF discharge. The lamp, the electrode, and the arrangement thereof may be basically the same as those of the dielectric barrier discharge, but the high frequency applied between the two electrodes is lit at several MHz. In the electrodeless field discharge, a spatially and temporally uniform discharge can be obtained in this way.

The xenon lamp emits ultraviolet light having a short wavelength of 172 nm at a single wavelength and thus has excellent luminous efficiency. With this high energy of 172 nm, the leveling agent on the surface layer of the hard coat layer can be decomposed in a short time.

Also, since the excimer lamp has high light generation efficiency, it can be turned on with low power. In addition, light having a long wavelength that causes a temperature increase due to light is not emitted, and energy of a single wavelength is irradiated in the ultraviolet region, so that an increase in the surface temperature of the irradiation object is suppressed. For this reason, it is also suitable for irradiation to a resin film that is easily affected by heat.

(the film)
The resin film used in this embodiment may be an unstretched film or a stretched film. A stretched film is preferable from the viewpoint of strength improvement and thermal expansion suppression. For example, acrylic resin, polycarbonate resin, cycloolefin resin, polyester resin, polylactic acid resin, polyvinyl alcohol resin, cellulose resin, and the like can be used. Among these, it is preferable to use a cellulose resin in consideration of heat resistance.

<Cellulosic resin>
Cellulosic resins used for the resin film include cellulose ethers such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cyanoethyl cellulose, triacetyl cellulose (TAC), diacetyl cellulose (DAC), cellulose acetate propionate (CAP). ), Cellulose esters such as cellulose acetate butyrate (CAB), cellulose acetate phthalate, cellulose acetate trimellitate, and cellulose nitrate, and cellulose esters are preferred. Alternatively, aromatic carboxylic acid esters described in paragraph numbers [0010] to [0027] of JP-A No. 2002-179701 are used, and in particular, celluloses of paragraph numbers [0028] to [0036] of JP-A No. 2002-17979. Acylate is preferably used.

The cellulose used as the raw material for the cellulose resin is not particularly limited, and examples thereof include cotton linter, wood pulp, and kenaf. Moreover, although the cellulose resin obtained from these can be used individually or in mixture of arbitrary ratios, it is preferable to use 50 mass% or more of cotton linters.

When the molecular weight of the cellulose ester is large, the elastic modulus is increased. However, when the molecular weight is excessively increased, the viscosity of the solution of the cellulose ester becomes too high, and the productivity is lowered. The molecular weight of the cellulose ester is preferably 70000-200000 in terms of number average molecular weight, more preferably 100000-200000. The cellulose ester used in the present embodiment preferably has a weight average molecular weight of Mw, a number average molecular weight of Mn, and a Mw / Mn ratio of 1.4 to 3.0, more preferably 1.4 to 2. 3.

Since the average molecular weight and molecular weight distribution of cellulose ester can be measured using high performance liquid chromatography, the number average molecular weight (Mn) and the weight average molecular weight (Mw) are calculated using this, and the ratio is calculated. be able to. Measurement conditions are as follows.

Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Sciences)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Co., Ltd.) Mw = 1,000,000-500 calibration curves with 13 samples were used. The 13 samples are preferably used at approximately equal intervals.

The total acyl group substitution degree of cellulose ester is preferably 1.0 to 2.9, more preferably 1.5 to 2.9. The total degree of acyl group substitution can be measured according to ASTM-D817-96.

<Additive>
The film of the present embodiment includes a plasticizer that imparts processability, flexibility, and moisture resistance to the film, an ultraviolet absorber that imparts an ultraviolet absorption function, fine particles (matting agent) that impart slipperiness to the film, and deterioration of the film. You may contain the antioxidant etc. which prevent this.

《Plasticizer》
There is no particular limitation on the plasticizer used, but it has a functional group capable of interacting with the adhesive layer so as not to cause haze or bleed out or volatilization from the film. preferable.

Examples of such functional groups include hydroxyl groups, ether groups, carbonyl groups, ester groups, carboxylic acid residues, amino groups, imino groups, amide groups, imide groups, cyano groups, nitro groups, sulfonyl groups, sulfonic acid residues, Examples thereof include a phosphonyl group and a phosphonic acid residue, and a carbonyl group, an ester group and a phosphonyl group are preferred.

Examples of such plasticizers include phosphate ester plasticizers, phthalate ester plasticizers, trimellitic acid ester plasticizers, pyromellitic acid plasticizers, polyhydric alcohol ester plasticizers, glycolate plasticizers. Agents, citrate plasticizers, fatty acid ester plasticizers, carboxylic acid ester plasticizers, polyester plasticizers, and the like can be preferably used. Particularly preferred are non-phosphate ester plasticizers such as polyhydric alcohol ester plasticizers, glycolate plasticizers, and polycarboxylic acid ester plasticizers.

The polyhydric alcohol ester is composed of an ester of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule.

<Ultraviolet absorber>
The film of this embodiment may contain an ultraviolet absorber. A layer having an ultraviolet absorbing function may be formed on the film.

As the ultraviolet absorber having an ultraviolet absorbing function, those having an excellent ability to absorb ultraviolet rays having a wavelength of 370 nm or less and little absorption of visible light having a wavelength of 400 nm or more are preferably used. Specific examples of preferably used ultraviolet absorbers include triazine compounds, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. However, it is not limited to these. Further, a polymeric ultraviolet absorber described in JP-A-6-148430 is also preferably used.

《Matting agent》
To the film of this embodiment, fine particles such as a matting agent can be added in order to impart slipperiness. Examples of the fine particles include fine particles of an inorganic compound or fine particles of an organic compound.

Examples of inorganic compounds include fine particles such as silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, and tin oxide. In this, it is preferable that it is a compound containing a silicon atom, and especially a silicon dioxide fine particle is preferable. Examples of the silicon dioxide fine particles include AEROSIL 200, 200V, 300, R972, R972V, R974, R202, R812, R805, OX50, and TT600 manufactured by Aerosil Co., Ltd.

Examples of organic compounds include acrylic resins, silicone resins, fluorine compound resins, and urethane resins.

"Antioxidant"
Antioxidants are also referred to as deterioration inhibitors. When placed in a high humidity and high temperature state, the optical film may deteriorate. Antioxidants have the role of delaying or preventing the optical film from being decomposed by, for example, the residual solvent amount of halogen in the optical film or phosphoric acid of the phosphoric acid plasticizer, so it is contained in the optical film. It is preferable to do so.

As such an antioxidant, a hindered phenol compound is preferably used, and in particular, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di- -T-butyl-4-hydroxyphenyl) propionate] and triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] are preferred. Further, for example, hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di- A phosphorus processing stabilizer such as t-butylphenyl) phosphite may be used in combination.

(Other layers)
The hard coat film of this embodiment can be provided with other layers such as an antireflection layer and a conductive layer.

<Antireflection layer>
The hard coat film of this embodiment can be used as an antireflection film having an antireflection function for external light by coating an antireflection layer on the hard coat layer.

The antireflection layer is preferably laminated in consideration of the refractive index, the film thickness, the number of layers, the layer order, and the like so that the reflectance is reduced by optical interference. The antireflection layer is composed of a low refractive index layer having a lower refractive index than the protective film as the support, or a combination of a high refractive index layer and a low refractive index layer having a higher refractive index than the protective film as the support. Preferably it is. Particularly preferably, it is an antireflection layer composed of three or more refractive index layers, and three layers having different refractive indexes from the support side are divided into medium refractive index layers (high refractive index layers having a higher refractive index than the support). Are preferably laminated in the order of a layer having a lower refractive index) / a high refractive index layer / a low refractive index layer. Alternatively, an antireflection layer having a layer structure of four or more layers in which two or more high refractive index layers and two or more low refractive index layers are alternately laminated is also preferably used. As the layer structure, the following structure is conceivable, but is not limited thereto.
Cellulose ester film / hard coat layer / low refractive index layer cellulose ester film / hard coat layer / high refractive index layer / low refractive index layer cellulose ester film / hard coat layer / medium refractive index layer / high refractive index layer / low refractive index Layer hard coat layer / cellulose ester film / hard coat layer / low refractive index layer hard coat layer / cellulose ester film / hard coat layer / high refractive index layer / low refractive index layer hard coat layer / cellulose ester film / hard coat layer / Medium refractive index layer / high refractive index layer / low refractive index layer low refractive index layer / hard coat layer / cellulose ester film / hard coat layer / low refractive index layer

<Low refractive index layer>
The low refractive index layer preferably contains silica-based fine particles, and the refractive index is preferably in the range of 1.30 to 1.45 when measured at 23 ° C. and wavelength of 550 nm.

The film thickness of the low refractive index layer is preferably in the range of 5 nm to 0.5 μm, more preferably in the range of 10 nm to 0.3 μm, and in the range of 30 nm to 0.2 μm. Most preferred.

The composition for forming a low refractive index layer preferably contains at least one kind of particles having an outer shell layer and porous or hollow inside as silica-based fine particles. In particular, the particles having the outer shell layer and porous or hollow inside are preferably hollow silica-based fine particles.

The composition for forming a low refractive index layer may contain an organosilicon compound represented by the following general formula (OSi-1) or a hydrolyzate thereof, or a polycondensate thereof.

General formula (OSi-1): Si (OR) ₄
In the organosilicon compound represented by the general formula, R represents an alkyl group having 1 to 4 carbon atoms. Specifically, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and the like are preferably used.

In addition, a solvent, and if necessary, a silane coupling agent, a curing agent, a surfactant and the like may be added. Further, it may contain a thermosetting and / or photocurable compound mainly containing a fluorine-containing compound containing a fluorine atom in a range of 35 to 80% by mass and containing a crosslinkable or polymerizable functional group. Specifically, a fluorine-containing polymer or a fluorine-containing sol-gel compound is used. Examples of the fluorine-containing polymer include hydrolysates and dehydration condensates of perfluoroalkyl group-containing silane compounds [eg (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane], and fluorine-containing monomers. Examples thereof include fluorine-containing copolymers having units and cross-linking reactive units as constituent units. In addition, you may add a solvent, a silane coupling agent, a hardening | curing agent, surfactant, etc. as needed.

《High refractive index layer》
The refractive index of the high refractive index layer is preferably adjusted to a range of 1.4 to 2.2 by measuring at 23 ° C. and a wavelength of 550 nm. The thickness of the high refractive index layer is preferably 5 nm to 1 μm, more preferably 10 nm to 0.2 μm, and most preferably 30 nm to 0.1 μm. The means for adjusting the refractive index can be achieved by adding metal oxide fine particles and the like. The metal oxide fine particles used preferably have a refractive index of 1.80 to 2.60, more preferably 1.85 to 2.50.

The kind of metal oxide fine particles is not particularly limited, and Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P and S A metal oxide having at least one element selected from can be used.

<Conductive layer>
In the hard coat film, a conductive layer may be formed on the hard coat layer. As the conductive layer provided, a generally well-known conductive material can be used. For example, metal oxides such as indium oxide, tin oxide, indium tin oxide, gold, silver, and palladium can be used. These can be formed as a thin film on the hard coat film by vacuum deposition, sputtering, ion plating, solution coating, or the like. Alternatively, the conductive layer can be formed using an organic conductive material that is a π-conjugated conductive polymer.

In particular, a conductive material that is excellent in transparency and conductivity, and that has a main component of any one of indium oxide, tin oxide, and indium tin oxide obtained at a relatively low cost can be suitably used. Although the thickness of the conductive layer varies depending on the material to be applied, it cannot be said unconditionally. However, the surface resistivity is 1000Ω or less, preferably 500Ω or less, and considering the economy, A range of 10 nm or more, preferably 20 nm or more and 80 nm or less, preferably 70 nm or less is suitable. In such a thin film, visible light interference fringes due to uneven thickness of the conductive layer are unlikely to occur.

〔Polarizer〕
A polarizing plate using the hard coat film of this embodiment will be described. The polarizing plate can be produced by a general method.

For example, it is preferable that the hard coat layer side of the hard coat film of the present embodiment is bonded to at least one surface of a polarizing film produced by immersing and stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. The other surface may use the hard coat film or the above-described film. In addition, commercially available products such as KC8UX, KC4UX, KC4UY, KC8UY, KC6UA, KC4UA, KC4UE, KC4CZ, KC8UCR, KC4FR (manufactured by Konica Minolta Advanced Layer Co., Ltd.), Arton Film (manufactured by JSR Corporation), Zeor Film Nippon Zeon Co., Ltd.) can be used.

The polarizing film, which is the main component of the polarizing plate, is an element that transmits only light having a polarization plane in a certain direction. A typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol film. There are those in which iodine is dyed on a system film and those in which dichroic dye is dyed, but it is not limited to this.

For the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxial stretching or dyeing, or after uniaxial stretching after dyeing, a film subjected to durability treatment with a boron compound is preferably used. The thickness of the polarizing film is in the range of 5 to 30 μm, preferably in the range of 8 to 15 μm.

The polarizing plate is formed by bonding the hard coat surface of the hard coat film of the present embodiment on the surface of the polarizing film. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.

〔Example〕
Hereinafter, specific examples of the present invention will be described as examples. For comparison with the present invention, comparative examples will also be described. The present invention is not limited to the following examples. In the following description, “parts” or “%” indicates “parts by mass” or “mass%” unless otherwise specified.

<Film>
KC4UAW (thickness: 40 μm), which is a triacetylcellulose film manufactured by Konica Minolta, Inc., was prepared as a film serving as a base material for the hard coat film.

<Hard Coat Layer Composition A>
The materials were mixed at the following ratio, and filtered through a polypropylene filter having a pore diameter of 0.4 μm to prepare a hard coat layer composition A.
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.) 55 parts by mass Trimethylolpropane triacrylate (A-TMPT, manufactured by Shin-Nakamura Chemical Co., Ltd.) 45 parts by mass ( Photopolymerization initiator)
Irgacure 184 (manufactured by BASF Japan) 6 parts by mass (leveling agent)
Fluorine-siloxane graft compound (35% by mass) 2 parts by mass (solvent)
Propylene glycol monomethyl ether 20 parts by weight Methyl acetate 30 parts by weight Methyl ethyl ketone 70 parts by weight

<Preparation of fluorine-siloxane graft compound>
The above-mentioned fluorine-siloxane graft compound was prepared by synthesizing a radical polymerizable fluororesin as described below using the following materials.
Radical polymerizable fluororesin (A): Cefal coat CF-803 (hydroxy group number 60, number average molecular weight 15000; manufactured by Central Glass Co., Ltd.)
One-end radically polymerizable polysiloxane (B): Silaplane FM-0721 (number average molecular weight 5000; manufactured by Chisso Corporation)
Radical polymerization initiator: Perbutyl O (t-butylperoxy-2-ethylhexanoate; manufactured by NOF Corporation)
Curing agent: Sumidur N3200 (biuret type prepolymer of hexamethylene diisocyanate; manufactured by Sumika Bayer Urethane Co., Ltd.)

<< Synthesis of radical polymerizable fluororesin >>
Into a glass reactor equipped with a mechanical stirrer, thermometer, condenser and dry nitrogen gas inlet, the above-mentioned cefal coat CF-803 (1554 parts by mass), xylene (233 parts by mass), and 2-isocyanatoethyl methacrylate ( 6.3 parts by mass) and heated to 80 ° C. in a dry nitrogen atmosphere. After reacting at 80 ° C. for 2 hours and confirming that the absorption of isocyanate disappeared by the infrared absorption spectrum of the sampled material, the reaction mixture was taken out to obtain 50% by mass of a radically polymerizable fluororesin via a urethane bond. .

<< Preparation of fluorine-siloxane graft compound >>
In a glass reactor equipped with a mechanical stirrer, thermometer, condenser and dry nitrogen gas inlet, the above synthesized radical polymerizable fluororesin (26.1 parts by mass), xylene (19.5 parts by mass), acetic acid n-butyl (16.3 parts by mass), methyl methacrylate (2.4 parts by mass), n-butyl methacrylate (1.8 parts by mass), lauryl methacrylate (1.8 parts by mass), 2-hydroxyethyl methacrylate (1 8 parts by mass), FM-0721 (5.2 parts by mass), and perbutyl O (0.1 parts by mass) were heated to 90 ° C. in a nitrogen atmosphere, and held at 90 ° C. for 2 hours. Perbutyl O (0.1 part) was added, and the mixture was further maintained at 90 ° C. for 5 hours to obtain a 35 mass% fluorine-siloxane graft compound solution having a weight average molecular weight of 171,000. The weight average molecular weight was determined by GPC. The mass% of the fluorine-siloxane graft compound was determined by HPLC (liquid chromatography).

<Hard Coat Layer Composition B>
The materials were mixed at the following ratio, and filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a hard coat layer composition B.
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.) 55 parts by mass Trimethylolpropane triacrylate (A-TMPT, manufactured by Shin-Nakamura Chemical Co., Ltd.) 45 parts by mass ( Photopolymerization initiator)
Irgacure 184 (manufactured by BASF Japan) 6 parts by mass (leveling agent)
BYK-UV3510 (polyether-modified polydimethylsiloxane, 2 parts by mass (solvent) manufactured by Big Chemie Japan Co., Ltd.)
Propylene glycol monomethyl ether 20 parts by weight Methyl acetate 30 parts by weight Methyl ethyl ketone 70 parts by weight

<Example 1>
On the above film, the hard coat layer composition A is applied using an extrusion coater, dried at a constant rate drying zone temperature of 50 ° C. and a reduced rate drying zone temperature of 50 ° C., and an oxygen concentration of 1.0 volume. % with a nitrogen purge so that the following atmosphere at 100 mW / cm ² illuminance in the irradiated portion using an ultraviolet lamp to cure the coated layer to the amount of radiation as 0.2 J / cm ^2, dry film thickness 2.5μm A hard coat layer was formed. Subsequently, the hard coat layer was irradiated with excimer light under the following conditions using an excimer irradiation apparatus (MECL-M-1-200) manufactured by M.D. A hard coat film was produced.
(Excimer light irradiation conditions)
Lamp filled gas: Xe
Wavelength: 172nm
Excimer light intensity: 130 mW / cm ² (172 nm)
Distance between sample and light source: 2mm
Oxygen concentration in irradiation device: 0.3% (nitrogen purge)
Integrated light quantity of light having a wavelength shorter than 200 nm: 1600 mJ / cm ²

<Example 2>
A hard coat film of Example 2 was obtained in the same manner as in Example 1 except that the hard coat layer composition B was used instead of the hard coat layer composition A.

<Example 3>
The hard coat of Example 3 was used in the same manner as in Example 1 except that the hard coat layer composition B was used in place of the hard coat layer composition A, and the cumulative amount of light having a wavelength shorter than 200 nm was 500 mJ / cm ^2. A film was obtained.

<Example 4>
The hard of Example 4 is the same as Example 1 except that the hard coat layer composition B is used in place of the hard coat layer composition A and the integrated light quantity of light having an wavelength shorter than 200 nm is 2000 mJ / cm ^2. A coated film was obtained.

<Example 5>
The hard coat of Example 5 was used in the same manner as in Example 1 except that the hard coat layer composition B was used instead of the hard coat layer composition A, and the integrated light quantity of light having a wavelength shorter than 200 nm was 3500 mJ / cm ^2. A film was obtained.

<Comparative Example 1>
A hard coat film of Comparative Example 1 was obtained in the same manner as in Example 1 except that no excimer light was irradiated.

<Comparative example 2>
A hard coat film of Comparative Example 2 was obtained in the same manner as in Example 1 except that the hard coat layer composition B was used in place of the hard coat layer composition A and no excimer light was irradiated.

<Comparative Example 3>
A hard coat film of Comparative Example 3 was obtained in the same manner as Example 1 except that corona treatment (discharge amount: 130 W / m ² / min) was performed instead of excimer light irradiation.

<Comparative example 4>
A hard coat film of Comparative Example 4 was obtained in the same manner as in Example 1 except that UV treatment (300 mJ / cm ² ) was performed instead of excimer light irradiation.

<Comparative Example 5>
The hard coat of Comparative Example 5 was made in the same manner as in Example 1 except that the hard coat layer composition B was used instead of the hard coat layer composition A, and the integrated light quantity of light having a wavelength shorter than 200 nm was 30 mJ / cm ^2. A film was obtained.

<Comparative Example 6>
The hard coat film of Comparative Example 6 was prepared in the same manner as in Example 1 except that the hard coat layer composition B was used in place of the hard coat layer composition A, and the integrated light quantity at the time of excimer light irradiation was 6000 mJ / cm ^2. Obtained.

<Evaluation of Examples and Comparative Examples>
About the hard coat film of an Example and a comparative example, the measurement of the water contact angle immediately after preparation, the measurement of the water contact angle two weeks after preparation, and the abrasion resistance evaluation by the steel wool test were performed. The results are shown in Table 1.

The measuring method and evaluation criteria for water contact angle are as follows. The hard coat film immediately after preparation was conditioned at a temperature of 23 ° C. and a relative humidity of 55% RH for 24 hours. Under this temperature and humidity, the contact angle of water on the surface of the hard coat layer with a contact angle meter CA-A (Kyowa Interface Chemistry) (Manufactured by Co., Ltd.), and the water droplet diameter was 1.0 mm. Further, the contact angle with water was measured in the same manner for the hard coat film two weeks after the production. If the contact angle with water was 65 ° or less immediately after the production and two weeks after the production, it was judged that there was no practical problem.

The steel wool test method and scratch resistance evaluation criteria are as follows. For the hard coat films of Examples 3 to 5 and Comparative Examples 5 and 6, the surface of the hard coat layer was reciprocated 10 times with steel wool applied with a load of 500 g / cm ² (manufactured by Nippon Steel Wool Co., Ltd., # 0000). The occurrence of scratches was visually observed.

(Evaluation criteria)
○: Less than 5 scratches Δ: There are 5 or more and less than 10 scratches ×: There are 10 or more scratches

From Table 1, in Examples 1 and 2 having different hard coat layer compositions, the water contact angle immediately after the production and the water contact angle two weeks after the production show substantially the same value. It can be seen that there is no difference in the water contact angle depending on the difference between the objects A and B.

Also, from Table 1, in Comparative Examples 1 and 2 where the hard coat layer surface modification treatment (excimer light irradiation, corona treatment or UV treatment) was not performed, the water contact angle immediately after production and two weeks after production, respectively. Since the contact angle with water shows the same value, it can be said that the contact angle with water does not decrease unless surface modification treatment is performed.

Further, from Table 1, in Comparative Example 3 in which the hard coat layer was corona-treated and in Comparative Example 4 in which the hard coat layer was UV-treated, the contact angle with water decreased to some extent immediately after the production, but after 2 weeks from the production, the treatment was performed. It has returned to the same level as that of Comparative Example 1. Therefore, since the contact angle to water is not low, the hard coat film that has been surface-modified is stored, and the hard coat film is made into a polarizing plate in the manufacturing process of the display device. Not available. In addition, in the UV treatment, the contact angle with water immediately after the production does not decrease so much and it cannot be said that it is sufficient.

Also, from Table 1, in Examples 1 to 5 and Comparative Examples 5 and 6 irradiated with excimer light, the water contact angle after 2 weeks from the production hardly changed from the water contact angle immediately after the production. Therefore, it can be said that continuous contact angle reduction can be realized by using excimer light as the surface modification treatment of the hard coat layer.

Further, from Table 1, when Examples 2 to 5 and Comparative Examples 5 and 6 in which the accumulated amount of excimer light is different are seen, in Comparative Example 5 where the accumulated light amount is as small as 50 mJ / cm ² , the water contact angle is 70 ° immediately after the production. And big. This is probably because the leveling agent on the surface layer of the hard coat layer was not sufficiently decomposed and the contact angle with water did not decrease so much because the integrated light quantity was insufficient. On the other hand, in Examples 2 to 5 and Comparative Example 6 in which the integrated light quantity is 50 mJ / cm ² or more, the contact angle with water is 65 ° or less immediately after the production. This is presumably because the leveling agent on the surface of the hard coat layer was sufficiently decomposed and the contact angle with water was sufficiently lowered because the integrated light quantity was sufficient.

Further, from Table 1, the scratch resistance of Examples 3 to 5 and Comparative Example 6 is seen. When the integrated light quantity of light having a wavelength shorter than 200 nm is 50 to 5000 mJ / cm ² , the scratches are less than 5 and practical. On the other hand, if the integrated light quantity of light with a wavelength shorter than 200 nm is 6000 mJ / cm ² , there are as many as 10 or more scratches and there is a practical problem. Therefore, if the integrated light amount of light with a wavelength shorter than 200 nm is 50 to 5000 mJ / cm ² , the intensity of the hard coat layer has no practical problem, but the integrated light amount of light with a wavelength shorter than 200 nm is 6000 mJ. When it is increased to / cm ² or the like, it is considered that the hard coat resin on the surface of the hard coat layer deteriorates and becomes brittle, and is easily damaged. Therefore, it is considered that the integrated light quantity of light having a wavelength shorter than 200 nm is appropriately 50 to 5000 mJ / cm ² .

From the above, the hard coat films of Examples 1 to 5 achieve a continuous low contact angle and scratch resistance.

The hard coat film of the present invention is used as a base for forming a conductive film, an antireflection film or the like, or is used on the outermost surface of a display device, and a touch panel or a cover glass is bonded to the surface of a tablet terminal or a smartphone. Can be used.

10 Hard Coat Film 11 Film 12 Hard Coat Resin 12a Hard Coat Resin 12b Leveling Agent

Claims

A hard coat film having a hard coat layer containing a hard coat resin and a leveling agent formed on a resin film is irradiated with light containing light having a wavelength shorter than 200 nm, and an integrated light quantity of light having a wavelength shorter than 200 nm is 50 mJ / cm 2 or more. By irradiating to 5000 mJ / cm 2 or less, the leveling agent on the surface layer of the hard coat layer is decomposed, and the hard coat resin on the surface layer of the hard coat layer has at least light with a wavelength shorter than 200 nm. A method for producing a hard coat film, wherein a part of the hard coat film is absorbed.
2. The method for producing a hard coat film according to claim 1, wherein an integrated light amount of light having a wavelength shorter than 200 nm is 500 mJ / cm 2 or more and 3500 mJ / cm 2 or less.
3. The method for producing a hard coat film according to claim 1, wherein the light containing light having a wavelength shorter than 200 nm is excimer light.
The method for producing a hard coat film according to claim 3, wherein a wavelength range of light included in the excimer light is in a range of 100 nm to 230 nm.
5. The method for producing a hard coat film according to claim 1, wherein the hard coat resin is an ultraviolet curable acrylate resin.
The method for producing a hard coat film according to any one of claims 1 to 5, wherein the leveling agent is a fluorine-siloxane graft compound.
The method for producing a hard coat film according to any one of claims 1 to 6, wherein the film is a cellulose ester film.