JP2011227488A - Hard coat film, polarizer, and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard coat film having excellent peeling resistance.SOLUTION: A hard coat film 31 comprises a base film 312 and a hard coat layer 311 stacked on one surface of the base film 312. The hard coat layer 311 is formed by putting an active energy ray-curing resin composition containing an active energy ray-curing resin composition, a polymerization initiator, and a surfactant into contact with a mold for curing, and water contact angle θ of the hard coat layer 311 satisfies the following expression (1): |θ-θ|≤15° (1), where θrepresents water contact angle of a hard coat layer formed on one surface of the base film, with the active energy ray-curing resin composition, by curing in a gas at 25°C without in contact with a mold.

Description

  The present invention relates to a hard coat film. The present invention also relates to a polarizing plate and an image display device using the hard coat film.

  Image display devices such as liquid crystal displays, plasma display panels, cathode ray tube (CRT) displays, and organic electroluminescence (EL) displays are often hard to prevent scratches caused by various external forces. A coat film is provided. Such a hard coat film is generally subjected to an anti-glare treatment that scatters incident light and blurs the reflected image by forming fine irregularities on the surface.

  As a method for obtaining such a hard coat film, for example, in Patent Document 1, a resin composition for forming a hard coat layer is applied to an embossing roll, and then the base film is brought into contact with the embossing roll. A method is disclosed in which the resin composition is cured by irradiating ionizing radiation without adjusting the temperature to form a hard coat layer on a base film, and then the film is peeled from the roll. . Further, in Patent Document 2, after a resin composition for forming a hard coat layer is coated on a substrate film, the coating surface is brought into contact with an embossing roll, and the activity is not particularly adjusted without adjusting the contact temperature. A method is disclosed in which the resin composition is cured by irradiating energy rays to form a hard coat layer on a substrate film, and then the film is peeled from the roll.

International Publication No. 2008/020613 Pamphlet JP 2007-76089 A

  However, in the conventional hard coat film, the hard coat layer may be peeled off from the base film, and the peel resistance of the hard coat layer from the base film is not always sufficient. Then, the objective of this invention is providing the hard coat film excellent in the peeling resistance from the base film of a hard-coat layer.

  The present invention is a hard coat film comprising a base film and a hard coat layer laminated on one surface of the base film, the hard coat layer comprising an active energy ray curable resin, a polymerization initiator, and A hard coat which is formed by curing an active energy ray-curable resin composition containing a surfactant while being in contact with a mold, and a water contact angle θ of the hard coat layer satisfies the following formula (1) A film is provided.

| Θ ₀ −θ | ≦ 15 ° (1)

(In the formula, θ ₀ is the contact of water on the hard coat layer formed by curing the active energy ray-curable resin composition on one surface of the base film in a gas at 25 ° C. without contacting the mold) Represents a corner.)

  The present invention is also a method for producing the hard coat film, wherein the active energy ray curable resin composition comprises an active energy ray curable resin, a polymerization initiator and a surfactant on one surface of the base film. Coating the active energy ray-curable resin composition, irradiating the active energy ray-curable resin composition with an active energy ray while bringing the mold at 55 ° C. or lower into contact therewith, and curing the active energy ray-curable resin composition The present invention provides a method for producing a hard coat film comprising a step of forming a hard coat layer and a step of peeling the hard coat layer from the mold.

  Furthermore, the present invention provides a polarizing plate comprising the hard coat film described above and a polarizing film laminated on the other surface of the base film of the hard coat layer, the polarizing plate, and an image A display element, and the polarizing plate provides an image display device disposed on the viewing side of the image display element such that the polarizing film is closer to the image display element than the hard coat layer. Is.

  ADVANTAGE OF THE INVENTION According to this invention, the hard coat film excellent in the peeling resistance from the base film of a hard-coat layer is provided. The hard coat film is suitably used for polarizing plates and image display devices.

It is a schematic sectional drawing which shows an example of the fundamental layer structure of the image display apparatus of this invention.

<Hard coat film>
The present invention is a hard coat film comprising a base film and a hard coat layer laminated on one surface of the base film, the hard coat layer comprising an active energy ray curable resin, a polymerization initiator, and The active energy ray-curable resin composition containing a surfactant is formed by curing while contacting with a mold, and the water contact angle θ of the hard coat layer satisfies the following formula (1).

| Θ ₀ −θ | ≦ 15 ° (1)

In the formula, θ ₀ is the contact angle of water on the hard coat layer formed by curing the active energy ray-curable resin composition on one surface of the base film in a gas at 25 ° C. without contacting the mold. The contact angle with water of the hard coat layer formed in an air atmosphere.

  The hard coat film of this invention is excellent in the peeling resistance from the base film of a hard-coat layer by satisfy | filling said Formula (1).

  The base film is not particularly limited as long as it is an optically transparent film and transmits an active energy ray capable of curing the active energy ray-curable resin. A transparent resin film can be used. Specifically, cellulose resins such as cellulose acetate such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polycarbonate resins; (meth) acrylic resins such as polyacrylate and polymethyl methacrylate; polyethylene terephthalate; Examples thereof include films made of polyester resins such as polyethylene naphthalate; chain polyolefin resins such as polyethylene and polypropylene; cyclic polyolefin resins; styrene resins; polysulfone; polyethersulfone; Among these, a film made of cellulose acetate, polyethylene terephthalate, polymethyl methacrylate, etc. is preferable from the viewpoint of transparency, mechanical strength, thermal stability, low moisture permeability, isotropic property, etc., from the viewpoint of transparency and mechanical strength. A film made of cellulose acetate is more preferred.

  The thickness of the base film is preferably 20 μm or more and 250 μm or less, and more preferably 30 μm or more and 150 μm or less. When the thickness of the base film is less than 20 μm, it may be difficult to obtain sufficient hardness as a hard coat film. Moreover, it is not preferable that the thickness of the base film exceeds 250 μm from the viewpoint of the recent demand for thinning of the image display device and the cost. From the viewpoint of reducing the thickness of the entire hard coat film, the thickness of the base film is preferably 150 μm or less, more preferably 120 μm or less.

  Moreover, you may provide an antistatic layer and an easily bonding layer in the coating surface of the active energy ray curable resin composition of a base film, and / or the surface on the opposite side. The antistatic layer and the easy-adhesion layer are those that lower the coatability and adhesion of the active energy ray-curable resin composition, or those that cause excessive coloring and clouding, and the transmittance of the active energy ray is significantly reduced. There is no particular limitation as long as it is not allowed to be used, and conventionally known ones can be used.

  When the hard coat film of the present invention is used as an optical member constituting an optical application, particularly a liquid crystal display (LCD), for example, when used as a protective film for a polarizing plate, other optical members such as a polarizing film and a liquid crystal cell are used. In order to protect from ultraviolet rays, the substrate film preferably contains a UV absorber.

  The active energy ray-curable resin composition contains an active energy ray-curable resin that is polymerized and cured by irradiation with active energy rays, a polymerization initiator that generates radicals upon irradiation with active energy rays, and a surfactant. . The active energy ray-curable resin can contain, for example, a polyfunctional (meth) acrylate compound. The polyfunctional (meth) acrylate compound is a compound having at least two (meth) acryloyloxy groups in the molecule. Commercially available products may be used as the active energy ray-curable resin, the polymerization initiator, and the surfactant. In many cases, the active energy ray-curable resin composition is commercially available as an active energy ray-curable resin, a polymerization initiator, and other additives such as a surfactant added as necessary.

  Specific examples of polyfunctional (meth) acrylate compounds include, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) ) Acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, pentaglycerol tri (meth) acrylate, pentaerythritol tri (Meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerin tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipenta Rithritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tris ((meth) acryloyloxyethyl) isocyanurate; (meth) acryloyloxy on the phosphazene ring of the phosphazene compound Phosphazene-based (meth) acrylate compound into which a group is introduced; urethane obtained by reaction of a polyisocyanate having at least two isocyanate groups in the molecule with a polyol compound having at least one (meth) acryloyloxy group and a hydroxyl group (Meth) acrylate compound; for the reaction of at least two carboxylic acid halides with a polyol compound having at least one (meth) acryloyloxy group and hydroxyl group in the molecule Ri obtained polyester (meth) acrylate compound; and dimer of each compound, and the like oligomers, such as trimers. These compounds are used alone or in combination of two or more.

  The active energy ray curable resin may contain a monofunctional (meth) acrylate resin in addition to the polyfunctional (meth) acrylate compound. Examples of monofunctional (meth) acrylate compounds include hydroxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and 2-hydroxy-3. -Phenoxypropyl (meth) acrylate, glycidyl (meth) acrylate, etc. can be mentioned. These compounds may be used alone or in combination of two or more. The content of the monofunctional (meth) acrylate compound is preferably 10% by weight or less in the resin solid content of the active energy ray-curable resin composition.

  Moreover, the active energy ray-curable resin may contain a polymerizable oligomer. By including the polymerizable oligomer, the hardness of the hard coat layer can be adjusted. As the polymerizable oligomer, terminal (meth) acrylate polymethyl methacrylate, terminal styryl poly (meth) acrylate, terminal (meth) acrylate polystyrene, terminal (meth) acrylate polyethylene glycol, terminal (meth) acrylate acrylonitrile-styrene copolymer, terminal Examples thereof include macromonomers such as (meth) acrylate styrene-methyl (meth) acrylate copolymer. The content of the polymerizable oligomer is preferably 5 to 50% by weight in the resin solid content of the active energy ray-curable composition.

  Examples of the polymerization initiator contained in the active energy ray-curable resin composition include acetophenone, acetophenone benzyl ketal, anthraquinone, 1- (4-isopropylphenyl-2-hydroxy-2-methylpropan-1-one, and carbazole. Xanthone, 4-chlorobenzophenone, 4,4′-diaminobenzophenone, 1,1-dimethoxydeoxybenzoin, 3,3′-dimethyl-4-methoxybenzophenone, thioxanthone, 2,2-dimethoxy-2-phenylacetophenone, -(4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, triphenylamine, 2,4,6-trimethylbenzoyldi Phenylphosphine oxide, phenylbis (2,4,6-trimethylbenzoyl) -phosphine oxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, fluorenone, fluorene, benzaldehyde, Benzoin ethyl ether, benzoisopropyl ether, benzophenone, Michler ketone, 3-methylacetophenone, 3,3 ′, 4,4′-tetra-tert-butylperoxycarbonylbenzophenone (BTTB), 2- (dimethylamino) -1- [4 -(Morpholinyl) phenyl] -2-phenylmethyl) -1-butanone, 4-benzoyl-4'-methyldiphenyl sulfide, benzyl, and derivatives thereof. These polymerization initiators may be used alone or in combination of several kinds as necessary. The polymerization initiators exemplified above are all photopolymerization initiators that generate radicals upon irradiation with active energy rays.

  The polymerization initiator may be used in combination with a dye sensitizer. Examples of the dye sensitizer include xanthene, thioxanthene, coumarin, and ketocoumarin. Examples of the combination of the polymerization initiator and the dye sensitizer include a combination of BTTB and xanthene, a combination of BTTB and thioxanthene, a combination of BTTB and coumarin, and a combination of BTTB and ketocoumarin.

  The content of the polymerization initiator is preferably in the range of 1 to 10% by weight and more preferably in the range of 3 to 6% by weight with respect to the active energy ray curable resin. When the content of the polymerization initiator is less than 1% by weight, the curing reaction does not proceed sufficiently, and an uncured active energy ray-curable resin adheres to the mold, or a hard coat film having excellent hardness is obtained. It may not be possible. Moreover, when content of a polymerization initiator exceeds 10 weight%, the polymerization degree of active energy ray-curable resin will fall, and the hard coat film which has the outstanding hardness may not be obtained.

  As described above, the base film preferably contains a UV absorber, and the UV absorber usually absorbs ultraviolet rays having a wavelength of less than 360 to 380 nm. In the (first) curing step of the present invention, as described in detail later, it is preferable to cure the active energy ray-curable resin composition by irradiating active energy rays from the base film side. Therefore, it is desirable that at least one polymerization initiator included in the active energy ray-curable resin composition has an absorption wavelength of 380 nm or more. Examples of such a polymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), phenylbis (2,4,6-trimethylbenzoyl) -phosphine oxide, and the like. When all of the polymerization initiators contained in the active energy ray-curable resin composition are polymerization initiators having an absorption wavelength of less than 380 nm, the active energy ray curability is also obtained after the above-described (first) curing step. Many of the resins may remain uncured, and if such uncured active energy ray-curable resin remains attached to the mold after the substrate film is peeled off, it may cause contamination or the mold surface. This is not preferable because the shape cannot be accurately transferred.

  Here, “having an absorption wavelength of 380 nm or more” means that when an active energy ray having a wavelength of 380 nm or more is irradiated, radicals necessary and sufficient to start the polymerization reaction are generated and function effectively as a polymerization initiator. It means to do.

  As a UV absorber contained in the base film, it is possible to use only a polymerization initiator having no absorption wavelength at 380 nm or more by using a UV absorber having an absorption wavelength on the lower wavelength side. Become. In such an approach, the hard coat film obtained by the production method of the present invention is used in an image display device, with respect to an optical member such as a liquid crystal cell. It is effective when it is arranged on the backlight side of the liquid crystal panel. However, in the case where the hard coat film is disposed on the viewing side, that is, the front side (for example, the front side of the liquid crystal panel in a liquid crystal display) with respect to an optical member such as a liquid crystal cell in an image display device, From the viewpoint of protecting optical members such as liquid crystal cells from ultraviolet rays, a UV absorber that absorbs ultraviolet rays having a wavelength of less than 360 to 380 nm is added to the base film, and at least one kind contained in the active energy ray-curable resin is added. A polymerization initiator having an absorption wavelength of 380 nm or more is preferable.

  As the surfactant contained in the active energy ray-curable resin composition, a leveling agent for improving smoothness, a release agent for improving mold releasability with a mold, an antifouling property, etc. Examples thereof include an antifouling agent for developing fingerprint resistance and a conductive agent for preventing charging of the film. These additives are not particularly limited as long as they do not inhibit the polymerization reaction of the active energy ray-curable resin, and do not reduce the hardness after the polymerization reaction or the adhesion to the substrate film. Can be used.

  As the surfactant, a hydrocarbon surfactant, a fluorine surfactant, a silicon surfactant and the like can be appropriately selected and used, and two or more of these can be used in combination as required. . Among these, those containing a fluorine-based surfactant, a silicon-based surfactant, or both are more preferable from the viewpoint of functionality.

  Examples of fluorosurfactants include perfluoroalkyl group-containing carboxylates, perfluoroalkyl group-containing sulfonates, perfluoroalkyl group-containing phosphates, perfluoroalkyl group-containing carboxylates, perfluoroalkyl. Group-containing sulfonic acid esters, perfluoroalkyl group-containing phosphate esters, perfluoroalkyl group / lipophilic group-containing oligomers, perfluoroalkyl group / hydrophilic group / lipophilic group-containing oligomers, or the above-mentioned perfluoro And the like in which the alkyl group is replaced with a perfluoroalkenyl group.

  Examples of silicone surfactants include polyether-modified polysiloxanes, polyester-modified polysiloxanes, alkyl-modified polysiloxanes, aralkyl-modified polysiloxanes, higher fatty acid-modified polysiloxanes, epoxy-modified polysiloxanes, amino-modified Examples thereof include organically modified polysiloxanes and derivatives thereof such as polysiloxanes, carboxyl-modified polysiloxanes, alcohol-modified polysiloxanes and the like.

  In addition, a surfactant containing both a fluorine atom and a silicon atom can also be used, and examples thereof include a fluorination in which part or all of the hydrogen of the alkyl group of the silicon surfactant is substituted with fluorine. Examples thereof include modified polysiloxanes.

  The active energy ray-curable resin composition may contain a solvent in order to improve the coating property. Examples of the solvent include aliphatic hydrocarbons such as hexane and octane; aromatic hydrocarbons such as toluene and xylene; alcohols such as ethanol, 1-propanol, isopropanol and 1-butanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone. Esters such as ethyl acetate, butyl acetate and isobutyl acetate; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether and propylene glycol monoethyl ether; ethylene glycol monomethyl Appropriately selected from esterified glycol ethers such as ether acetate and propylene glycol monomethyl ether acetate It can be used Te. These organic solvents may be used alone or in combination as necessary. Since the solvent is preferably evaporated and dried after the coating process and before the (first) curing process, the boiling point of the solvent is preferably in the range of 60 to 160 ° C. Moreover, it is preferable that the saturated vapor pressure in 20 degreeC is the range of 0.1-20 kPa. The kind and content of the solvent are appropriately selected according to the kind and content of the active energy ray-curable compound to be used, the material and shape of the base film, the coating method, the thickness of the intended hard coat layer, and the like.

  Translucent fine particles may be added to the active energy ray-curable resin composition for the purpose of imparting internal haze to reduce glare and the like. The translucent fine particles are not particularly limited, and conventionally known fine particles can be used. For example, organic fine particles made of acrylic resin, melamine resin, polyethylene, polystyrene, organic silicone resin, acrylic-styrene copolymer, calcium carbonate, silica, aluminum oxide, barium carbonate, barium sulfate, titanium oxide, glass, etc. Inorganic fine particles and the like can be used as translucent fine particles. Organic polymer balloons and glass hollow beads can also be used. These translucent fine particles may be used individually by 1 type, and 2 or more types may be mixed and used for them. The shape of the translucent fine particles may be any of a spherical shape, a flat shape, a plate shape, a needle shape, an indefinite shape, and the like.

  The particle diameter and refractive index of the light-transmitting fine particles are not particularly limited, but the particle diameter is preferably in the range of 0.5 μm to 20 μm from the viewpoint of effectively expressing internal haze. For the same reason, the difference between the refractive index after curing of the active energy ray-curable resin and the refractive index of the translucent fine particles is preferably in the range of 0.04 to 0.15. Content of translucent fine particle is 3-60 weight part with respect to 100 weight part of active energy ray-curable resins, Preferably it is 5-50 weight part. When the content of the light-transmitting fine particles is less than 3 parts by weight with respect to 100 parts by weight of the active energy ray-curable resin, sufficient internal haze for reducing glare cannot be obtained. On the other hand, if it exceeds 60 parts by weight, the transparency of the hard coat film may be impaired, and when the hard coat film is arranged on the viewing side in the liquid crystal display device, light scattering is too strong, for example, black display However, the contrast may be lowered due to the reason that light leaking obliquely with respect to the front direction of the liquid crystal panel is strongly scattered by the hard coat layer in the front direction.

  The mold is for imparting a desired shape to the surface of the hard coat layer, and has a surface shape composed of a transfer structure of the desired shape. The surface shape of the mold may be a smooth surface such as a mirror surface, or may be an uneven shape for imparting antiglare properties to the hard coat film. The uneven pattern may be a regular pattern, a random pattern, or a pseudo random pattern in which one or more random patterns of a specific size are spread, but the surface shape of the hard coat film From the viewpoint of preventing the reflected image from becoming iridescent due to the interference of the reflected light caused by the above, it is preferably a random pattern or a pseudo-random pattern.

  The shape of the mold is not particularly limited, and it may be a flat plate shape or a cylindrical or cylindrical roll, but from the viewpoint of continuous productivity, such as a mirror surface roll or an embossing roll, It is preferably a columnar or cylindrical mold. In this case, a predetermined surface shape is formed on the side surface of the columnar or cylindrical mold.

  The material of the base material of the mold is not particularly limited and can be appropriately selected from metal, glass, carbon, resin, or a composite thereof, but metal is preferable from the viewpoint of workability and the like. Suitable metal materials include aluminum, iron, or an alloy mainly composed of aluminum or iron from the viewpoint of cost.

  As a method for obtaining a mold, for example, a method of polishing a base material, sandblasting, and then applying electroless nickel plating to create a roll mold (Japanese Patent Laid-Open No. 2006-53371); After plating or nickel plating, polishing, sandblasting, and chromium plating (Japanese Patent Laid-Open No. 2007-188792); after copper plating or nickel plating, polishing and sandblasting After applying, a method of performing an etching step or a copper plating step, and then performing a chromium plating (Japanese Patent Laid-Open No. 2007-237541); applying a copper plating or a nickel plating to the surface of the mold substrate, polishing, A photosensitive resin film is applied and formed on the polished surface, a pattern is exposed on the photosensitive resin film, developed, and developed. Etching treatment using the film as a mask, peeling off the photosensitive resin film, further etching treatment, dulling the uneven surface, and then chrome plating the formed uneven surface; and tools such as lathes Examples include a method of cutting a base material to be a mold with a cutting tool using a machine (International Publication No. 2007/077892 pamphlet).

  The surface irregularity shape of the mold consisting of a random pattern or a pseudo-random pattern is, for example, an FM screen method, a DLDS (Dynamic Low-Discretion Sequence) method, a method using a microphase separation pattern of a block copolymer, a bandpass filter method, or the like The random pattern generated by the above can be formed by exposing and developing on the photosensitive resin film, and performing an etching process using the developed photosensitive resin film as a mask.

In the present invention, as a standard, the contact angle of water on the hard coat layer formed by curing the active energy ray-curable resin composition on one surface of the base film in a gas at 25 ° C. without contacting the mold. θ ₀ is measured, and θ ₀ and the water contact angle θ of the hard coat layer of the present invention formed by curing the active energy ray-curable resin composition while being in contact with the mold, Equation (1) is satisfied. Note that | θ ₀ −θ | in Equation (1) means the absolute value of the difference between θ ₀ and θ. When the value of | θ ₀ −θ | exceeds 15 °, the hard coat layer may be easily peeled off from the base film.

In order to reduce the value of | θ ₀ −θ | to 15 ° or less, for example, a method of controlling the temperature of the mold, a method of using a surfactant having a low surface tension reducing ability, and a reduction in the amount of the surfactant added. Although the method, a method of applying a special surface treatment such as fluorine coating to the mold to reduce the surface free energy of the mold, etc. can be adopted as appropriate, the leveling property, after curing, without excessively reducing the amount of surfactant added By controlling the temperature of the mold, it is possible to obtain sufficient effects due to the addition of surfactants such as film slipperiness and water repellency, and because the production of molds and production equipment is relatively easy. A method of adjusting the value of θ ₀ −θ | to 15 ° or less is preferable. Specifically, for example, by controlling the temperature of the mold to 55 ° C. or less, the value of | θ ₀ −θ | can be made 15 ° or less.

<Method for producing hard coat film>
Next, the manufacturing method of the hard coat film of this invention is demonstrated. The hard coat film of the present invention comprises a step of coating an active energy ray-curable resin composition containing an active energy ray-curable resin, a polymerization initiator and a surfactant on one surface of a base film, Irradiating the active energy ray-curable resin composition with an active energy ray while contacting a mold of 55 ° C. or less to cure the active energy ray-curable resin composition to form a hard coat layer; And a step of peeling the hard coat layer from the mold. That is, it includes [1] coating step, [2] curing step, and [3] peeling step in this order, and will be described in detail below.

[1] Coating process The above-mentioned active energy ray-curable resin is coated on one surface of the above-described base film to form a coating layer. As such a coating method, a known method can be appropriately selected. Specifically, a wire bar coating method, a roll coating method, a gravure coating method, a knife coating method, a slot die coating method, a spin coating method, a spray coating method, a slide coating method. Method, curtain coating method, ink jet method and the like. Among these, the slot die coating method is desirable from the viewpoint of preventing foreign matters and the like from being mixed into the active energy ray-curable resin composition during coating as much as possible.

[2] Curing process (first curing process)
Next, the coating layer is cured by irradiating the coating layer with the above-described mold and an active energy ray while bringing the surface temperature of the casting mold to 55 ° C. or less and contacting. Thereby, the surface shape of the mold is transferred to the coating layer, and a hard coat layer is formed. In this way, the contact temperature, that is, the mold surface temperature is set to 55 ° C. or lower, and curing is performed while contacting the mold, whereby a desired water contact angle can be obtained. It becomes possible to improve peeling resistance. On the other hand, when the contact temperature is lower than 20 ° C., there is a concern that the surface of the mold may be condensed.

  In order to achieve the contact temperature described above, it is preferable that the mold is provided with a cooling mechanism in order to protect it from overheating due to irradiation with active energy rays. Examples of such a cooling mechanism include a structure in which a cooling pipe is provided inside the mold, the cooling pipe inside the mold is connected to a chiller unit installed outside, and the refrigerant is circulated. With this cooling mechanism, it is possible to cool the surface of the mold, thereby adjusting the contact temperature to the above-described temperature.

  Although there is no restriction | limiting in particular in the method of sticking a coating layer and a casting_mold | template, In order to prevent that a bubble mixes between a coating layer and a casting_mold | template, it is preferable to use pressure bonding apparatuses, such as a nip roll. When a nip roll is used, the nip pressure is not particularly limited, but is preferably 0.05 MPa or more and 1.0 MPa or less. When the nip pressure is less than 0.05 MPa, bubbles are likely to be mixed between the coating layer and the mold. On the other hand, if the nip pressure exceeds 1.0 MPa, the base film may be broken due to a slight shift during transport of the base film, or the coating layer may protrude from the end of the base film and cause contamination. There is a case.

  The active energy ray can be appropriately selected from γ rays, X rays, ultraviolet rays, near ultraviolet rays, visible rays, near infrared rays, infrared rays, electron beams, etc., depending on the type of the active energy ray curable resin and the polymerization initiator. Of these, ultraviolet rays and electron beams are preferred, and ultraviolet rays are preferred from the viewpoint of excellent curability and productivity because they are particularly easy to handle and high energy is obtained.

  As an ultraviolet light source, 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 arc lamp, or the like can be used. However, there is no particular limitation as long as the light source generates ultraviolet rays. An ArF excimer laser, a KrF excimer laser, an excimer lamp, synchrotron radiation, or the like can also be used. Among these, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a xenon arc lamp, and a metal halide lamp can be preferably used.

  Examples of a combination of an ultraviolet irradiation device and a light source for irradiating ultraviolet rays include a UV irradiation device “F600” or “LH10” manufactured by Fusion UV SYSTEMS, an H bulb (equivalent to a mercury lamp), a D bulb or a V bulb (metal halide). Lamp combination), "GS series" manufactured by GS Yuasa Co., Ltd., and a combination of mercury lamp and metal halide lamp, UV irradiation devices such as "QRM-2288" and "QRM-2300" manufactured by Oak Manufacturing Co., Ltd. And a combination of a metal halide lamp and a high-pressure mercury lamp, and a combination of “Unicure System” manufactured by USHIO INC. With a metal halide lamp and a high-pressure mercury lamp. The ultraviolet irradiation device and the light source may be used alone or in combination, or plural different combinations may be used.

The integrated light quantity of UVA in UVA is preferably 40 mJ / cm ² or more, and more preferably 70 mJ / cm ² or more. When the integrated light quantity is less than 40 mJ / cm ² , the curing of the ultraviolet curable resin becomes insufficient, and the uncured ultraviolet curable resin may adhere to the mold. On the other hand, the upper limit of the integrated light amount is not particularly limited as long as it is within the above-described contact temperature range.

  Irradiation with ultraviolet rays may be performed only once or may be performed twice or more. Moreover, there is no restriction | limiting in particular in the number of the light sources (ultraviolet irradiation device) used in a hardening process, One lamp may be sufficient and two or more lamps may be sufficient.

[3] Peeling Step After the curing step, the hard coat film (a laminate of the base film and the hard coat layer) is peeled from the mold. The peeling method is not particularly limited. For example, when the mold is in a roll shape, a crimping device such as a nip roll is installed at a separation point between the hard coat film and the mold, and the film from the mold is used as a fulcrum. The method of peeling is preferably used. This effectively prevents the film from peeling off from the mold during irradiation with active energy rays, maintains the close contact between the mold and the film, and efficiently and stably peels off the film that has reached the fulcrum. It becomes possible to do.

  Thus, although the hard coat film of the present invention can be obtained, it is preferable to further irradiate active energy rays from the hard coat layer side for the purpose of further promoting the curing reaction of the hard coat layer. This process is called the second curing process and will be described below.

[4] Second curing step The active energy rays used in the second curing step can be appropriately selected from γ rays, X rays, ultraviolet rays, near ultraviolet rays, visible rays, near infrared rays, infrared rays, electron beams, etc. Among these, ultraviolet rays and electron beams are preferred, and ultraviolet rays are preferred from the viewpoint of excellent curability and productivity because handling is easy and high energy is obtained. Moreover, it is preferable to use the thing of the same kind as the active energy ray used in the case of the 1st hardening process mentioned above as an active energy ray. When different types of active energy rays are used, it is necessary to use a plurality of resins and polymerization initiators accordingly, and the design of the resin composition may be complicated.

  As the light source of the ultraviolet irradiation device used in the second curing step, 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 arc lamp, or the like may be used. However, it is not limited to these, and there is no particular limitation as long as it is a light source that generates ultraviolet rays. An ArF excimer laser, a KrF excimer laser, an excimer lamp, synchrotron radiation, or the like can also be used. Among these, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a xenon arc lamp, and a metal halide lamp can be preferably used. The ultraviolet irradiation device and the light source may be used alone or in combination, or plural different combinations may be used.

  Note that the type of ultraviolet irradiation device or light source used in the second curing step may be different from that in the first curing step as long as the polymerization initiator contained in the hard coat layer functions effectively. For example, a metal halide lamp may be used in the first curing step, and a high-pressure mercury lamp may be used in the second curing step.

The integrated light quantity of UVA in the second curing step is preferably 200 mJ / cm ² or more, more preferably 300 mJ / cm ² or more. There is no particular limitation on the upper limit of the integrated light quantity.

  The ultraviolet irradiation in the second curing step may be performed only once or may be performed twice or more. Also. There are no particular limitations on the number of ultraviolet irradiation devices or light sources used in the second curing step, and there may be only one lamp or two or more lamps. In addition, when performing an ultraviolet irradiation twice or more in a 2nd hardening process, the said integrated light quantity is a total value of the said integrated light quantity about the ultraviolet-ray of a 2nd hardening process.

  In the second curing step, in order to prevent the curing of the active energy ray-curable resin from being inhibited by oxygen, an inert gas is filled between the laminate composed of the base film and the hard coat layer and the irradiation device. It is preferable. The inert gas is appropriately selected from nitrogen, argon, neon, and the like, but nitrogen is preferable from the viewpoint of easy handling and cost. Further, the oxygen concentration at that time is preferably 0.1% or less.

  There is no restriction | limiting in particular in the specific irradiation method of the active energy ray in a 2nd hardening process, For example, you may irradiate in the state which made the base film closely_contact | adhere on rolls, such as a backup roll, A guide roll and a guide roll An active energy ray irradiating device may be installed in the hollow portion between the two. Further, when the active energy ray is irradiated twice or more, the irradiation method may be the same or different. For example, both the first time and the second time may be irradiated with an active energy ray using a backup roll, the first time is irradiated with an active energy ray using a backup roll, and the second time is a guide roll and a guide roll. An active energy ray irradiating device may be installed in the hollow portion between and the active energy rays may be irradiated.

  An irradiation method using a backup roll equipped with a cooling mechanism is preferable in order to prevent thermal damage to the base film caused by active energy rays and generation of hot soot. The surface temperature of the cooled backup roll is generally in the range of 10 ° C to 70 ° C, preferably in the range of 20 ° C to 60 ° C. When using a backup roll, you may install the scraping apparatus for preventing a flaw from entering a base film in the entrance side of a 2nd hardening process, or both the entrance side and exit side.

  In order to protect the hard coat layer and the base film, a protective film may be bonded to one side or both sides of the laminate of the base film and the hard coat layer as necessary.

  Although the hard coat film of this invention can be used as various optical members, it is used suitably as a protective film of a polarizing plate, for example. Further, the polarizing plate can be used for an image display device.

<Polarizing plate>
The polarizing plate of this invention has the hard coat film mentioned above and the polarizing film laminated | stacked on the other surface of the said base film of the said hard coat film. A polarizing film has a function which takes out linearly polarized light from incident light, The kind is not specifically limited. As an example of a suitable polarizing film, there can be mentioned a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin. Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol, which is a saponified product of vinyl acetate, partially formalized polyvinyl alcohol, and a saponified product of an ethylene / vinyl acetate copolymer. As the dichroic pigment, iodine or a dichroic organic dye is used. Further, a polyene-oriented film of a polyvinyl alcohol dehydrated product or a polyvinyl chloride dehydrochlorinated product can also be a polarizing film. The thickness of the polarizing film is usually about 5 to 80 μm.

  The polarizing plate of the present invention may be obtained by laminating the hard coat film of the present invention on one side or both sides (usually one side) of the polarizing film, and a transparent protective layer on one side of the polarizing film. It may be laminated and the hard coat film of the present invention laminated on the other surface. At this time, the hard coat film also has a function as a transparent protective layer of the polarizing film. When the surface of the hard coat film is provided with an uneven surface, the hard coat layer also has a function as an antiglare layer. A transparent protective layer is laminated | stacked by the method of bonding a film using an adhesive agent etc., the method of apply | coating a coating liquid, etc. Similarly, the hard coat film of the present invention can be bonded to a polarizing film using an adhesive or the like.

  The transparent protective layer is preferably excellent in transparency, mechanical strength, thermal stability, moisture shielding properties, and the like. Examples of such a protective layer include triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate. Cellulose resins such as cellulose acetate; Polycarbonate resins; (Meth) acrylic resins such as polyacrylate and polymethyl methacrylate; Polyester resins such as polyethylene terephthalate and polyethylene naphthalate; Chain polyolefins such as polyethylene and polypropylene Examples thereof include a film made of a resin; a cyclic polyolefin resin; a styrene resin; a polysulfone; a polyether sulfone; These films may be optically isotropic, or may have optical anisotropy for the purpose of compensating the viewing angle when incorporated in an image display device. .

  When the polarizing plate of the present invention is disposed on a liquid crystal cell to produce a liquid crystal panel, when the polarizing plate is disposed on one or both sides of the liquid crystal cell, the hard coat layer (or antiglare layer) of the polarizing plate of the present invention. The polarizing plate is arranged so that the polarizing film is closer to the liquid crystal cell than the polarizing film. At this time, the polarizing plate may be disposed on the viewing side, the backlight side, or both. When the polarizing plate is arranged on the viewing side, the hard coat layer prevents scratches and the like due to external force, and also prevents glare and reflection of external light when functioning as an antiglare layer. On the other hand, when the polarizing plate is arranged on the backlight side, the hard coat layer prevents scratches caused by external forces that may occur in the assembly process of the liquid crystal display, for example, scratches due to contact with the diffusion plate and the like. When it functions also as a glare layer, it plays the role of the diffusion plate which prevents a moire etc. with respect to the light which injects into a liquid crystal panel from a backlight.

<Image display device>
The image display device of the present invention is a combination of a hard coat film produced by the method of the present invention and an image display device that displays various information on a screen. In the image display device of the present invention, the type of the image display device is not particularly limited. In addition to the liquid crystal display (LCD) using the liquid crystal panel, a cathode ray tube (CRT) display, a plasma display (PDP), an electrolytic emission Examples thereof include a display (FED), a surface conduction electron-emitting device display (SED), an organic EL display, a laser display, and a projector television screen.

  The hard coat film according to the present invention is preferably disposed on the viewing-side surface of the image display element of these displays. In this case, the image display device includes a polarizing plate and an image display element, and the polarization The plate is disposed on the viewing side of the image display element such that the polarizing film is closer to the image display element than the hard coat layer. However, the hard coat film according to the present invention may be incorporated into the image display device as in the case where the hard coat film is disposed on the backlight side of the image display element. Since the image display device of the present invention is provided with the hard coat film according to the present invention, the image display device is hardly damaged and has excellent strength.

  FIG. 1 is a schematic cross-sectional view showing an example of a basic layer configuration of the image display apparatus of the present invention. The image display device 100 shown in FIG. 1 includes a backlight 10, a light diffusion plate 50, and a liquid crystal panel 60 in this order. The liquid crystal panel 60 includes an image display element 40, a polarizing plate 20 disposed on the backlight side of the image display element 40 (in the negative z-axis direction in FIG. 1), and a viewing side of the image display element 40 (z in FIG. 1). And a polarizing plate 30 arranged in the positive direction of the axis. The polarizing plate 30 disposed on the viewing side of the image display element 40 includes a hard coat film 31 and a polarizing film 33. The hard coat film 31 includes a base film 312 and a hard coat layer 311 stacked on one surface of the base film 312, and a polarizing film 33 is stacked on the other surface of the base film 312. In the image display device 100, the polarizing plate 30 is disposed on the viewing side of the image display element 40 such that the polarizing film 33 is closer to the image display element 40 than the hard coat layer 311. The perpendicular line of the light emitting surface of the backlight 10 is substantially parallel to the Z axis. Further, the perpendicular lines of the light incident surfaces of the light diffusion plate 50, the polarizing plate 20, the image display element 40, and the polarizing plate 30 are substantially parallel to the Z axis.

  The hard coat film 31 of the present invention used for the polarizing plate 30 of the image display device 100 of the present invention includes a base film 312 and a hard coat layer 311 laminated on one surface of the base film 312. The coat layer 311 is formed by curing an active energy ray curable resin composition containing an active energy ray curable resin, a polymerization initiator, and a surfactant while being in contact with a mold, and the hard coat layer 311 The water contact angle θ satisfies the above formula (1). The hard coat film 31 of the present invention is excellent in the peel resistance from the base film 312 of the hard coat layer 311.

  The image display device of the present invention is not limited to the configuration shown in FIG. 1, and various modifications can be made. For example, the polarizing plate 20 disposed on the backlight side of the image display element 40 in FIG. 1 may be the polarizing plate 30 including the hard coat film 31 of the present invention. May be arranged on both the viewing side and the backlight side, or may be arranged only on one side of the backlight side. When the polarizing plate 30 is disposed on the backlight side, the polarizing film 33 is placed on the image display element 40 so that the hard coat layer 311 is on the backlight side with respect to the polarizing film 33. It is preferable to arrange the polarizing plate 30 so as to be close to each other. Moreover, the light diffusing plate 50 and the backlight 10 are not necessarily required and may be omitted.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further more concretely, this invention is not limited by these examples.

[Measurement of water contact angle of hard coat film]
About the hard coat film mentioned later, the contact angle meter for water was measured using the Kyowa Interface Chemical Co., Ltd. contact angle meter and CA-X type.

[Measurement of peel resistance of hard coat film]
About the hard coat film mentioned later, based on JISK5400, the cross-cut test was done and the peeling resistance from the base film of a hard-coat layer was evaluated. Evaluation was performed by cutting the hard coat layer of the hard coat film into 100 squares of 10 squares × 10 squares so that 1 square is 1 mm square using CCJ-1 manufactured by Cortec as a guide. Using cello tape (registered trademark) CT-24, a peel test was performed three times, and the peeled state of the hard coat layer from the base film was compared.

[Example 1]
The following ultraviolet curable resin composition was used as an active energy ray curable resin composition.
・ UV curable resin: Trade name “NK HARD KCR2803-50A”
(Shin Nakamura Chemical Co., Ltd. urethane acrylate resin, resin solid content concentration: 60% by weight, diluent solvent: ethyl acetate, polymerization initiator: TPO (chemical name: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) Is contained in an amount of 5.0% by weight based on the resin solid content of the ultraviolet curable resin composition.)
・ Surfactant: Trade name “MegaFuck F-477”
(Added so as to be 0.5% by weight with respect to the resin solid content of the perfluoroalkyl group, hydrophilic group, lipophilic group-containing oligomer and ultraviolet curable resin composition.)

A triacetyl cellulose (TAC) film with a thickness of 80 μm (trade name “TDY80UL”, manufactured by Fuji Film Co., Ltd.) was applied with a die coater so that the film thickness after drying was 5 μm, and set to 60 ° C. And dried for 20 seconds in the dryer. Subsequently, the laminate of the obtained TAC film and the coating layer of the ultraviolet curable resin composition is placed on an embossing roll whose surface temperature is controlled at 38 ° C., at an ambient temperature of 25 ° C., and the coating layer is on the embossing roll side. It was pressed with a nip roll so as to adhere. In this state, UV light is irradiated once from the TAC film side using an Oak UV irradiation device as an ultraviolet irradiation device and a metal halide lamp as a light source so that the integrated light quantity of UVA is 200 mJ / cm ^2. The work layer was cured to form a hard coat layer.

Next, after peeling the TAC film from the embossing roll together with the hard coat layer, from the hard coat layer side, using a UV irradiation device manufactured by Oak as an ultraviolet irradiation device and a high-pressure mercury lamp as a light source, A hard coat film was prepared by irradiating ultraviolet rays once so that the integrated light quantity of UVA was 500 mJ / cm ² . Table 1 shows the results of the contact angle θ with water of the hard coat layer in the film and the peel resistance of the hard coat layer from the base film.

[Examples 2 and 3 and Comparative Example 1]
A hard coat film was prepared in the same manner as in Example 1 except that the surface temperature of the embossing roll was changed as shown in Table 1. Table 1 shows the results of the contact angle θ with water of the hard coat layer in these films and the peel resistance of the hard coat layer from the base film.

[Reference sample]
A hard coat film was prepared in the same manner as in Example 1 except that it was cured at room temperature (25 ° C.) and in an air atmosphere without being brought into contact with the embossing roll. Table 1 shows the water contact angle θ ₀ of the hard coat layer in the film.

DESCRIPTION OF SYMBOLS 10 ... Backlight, 20, 30 ... Polarizing plate, 31 ... Hard coat film, 311 ... Hard coat layer, 312 ... Base film, 33 ... Polarizing film, 40 ... Image display element, 50 ... Light diffusing plate, 60 ... Liquid crystal Panel, 100 ... Liquid crystal display device.

Claims (7)

A hard coat film comprising a base film and a hard coat layer laminated on one surface of the base film,
The hard coat layer is formed by curing an active energy ray curable resin composition containing an active energy ray curable resin, a polymerization initiator and a surfactant while being in contact with a mold, and the hard coat layer A hard coat film satisfying the following formula (1).
| Θ ₀ −θ | ≦ 15 ° (1)
(In the formula, θ ₀ is the contact of water on the hard coat layer formed by curing the active energy ray-curable resin composition on one surface of the base film in a gas at 25 ° C. without contacting the mold) Represents a corner.)   The hard coat film according to claim 1, wherein the surfactant is a fluorine-based surfactant and / or a silicon-based surfactant.   A step of applying an active energy ray-curable resin composition containing an active energy ray-curable resin, a polymerization initiator and a surfactant to one surface of the base film, and the applied active energy ray-curing property A step of irradiating the resin composition with an active energy ray while contacting a mold at 55 ° C. or lower to cure the active energy ray-curable resin composition to form a hard coat layer; and removing the hard coat layer from the mold A method of producing a hard coat film.   The method for producing a hard coat film according to claim 3, wherein the mold is a mirror roll or an emboss roll.   A polarizing plate comprising the hard coat film according to claim 1 and a polarizing film laminated on the other surface of the base film of the hard coat film.   A polarizing plate provided with the hard coat film manufactured by the method of Claim 3 or 4, and the polarizing film laminated | stacked on the other surface of the said base film of the said hard coat film. The polarizing plate according to claim 5 or 6, and an image display element,
The said polarizing plate is an image display apparatus arrange | positioned at the visual recognition side of the said image display element so that the said polarizing film may be near the said image display element rather than the said hard-coat layer.

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