JP2013088635A - Coating liquid for forming hard coat layer, method for manufacturing hard coat film using the coating liquid, and method for manufacturing optical filter for display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating liquid for forming a thick hard coat layer, the coating liquid capable of suppressing generation of stripe defects as well as generation of bubble defects and coating irregularity, and to provide a method for manufacturing a hard coat film and an optical filter for a display using the coating liquid.SOLUTION: The coating liquid is used to form a hard coat layer having a thickness of 3 μm or more, and the liquid comprises a resin composition and as a solvent, isobutyl alcohol and a solvent (A) having a boiling point higher than that of isobutyl alcohol. In the liquid, the content of the isobutyl alcohol is equal to or larger than the content of the solvent (A); and the coating liquid has a viscosity of 7 to 16 mPa s. The method for manufacturing a hard coat film or an optical filter for a display comprises applying the above coating liquid on a transparent substrate or a transparent substrate with a conductive layer formed thereon.

Description

  The present invention relates to a coating liquid for forming a hard coat layer, and in particular, an electromagnetic shielding property used for an image display portion of a display such as a thick film hard coat layer forming coating liquid, specifically, a plasma display panel (PDP). It is related with the coating liquid for hard-coat layer formation useful for manufacture of the optical filter for displays which has this. Moreover, it is related with the manufacturing method of the hard coat film which uses this coating liquid, and the manufacturing method of the optical filter for displays.

  Conventionally, surface protection, durability improvement, contamination prevention, improvement of optical properties, etc. for plastic film products such as display optical filters and touch panels used in displays such as plasma display panels (PDP) and liquid crystal displays, etc. Therefore, a hard coat layer is formed on the surface. Such a hard coat layer is also required to have high transparency and visibility, and the occurrence of defects due to adhesion of fine foreign matters and the occurrence of optical distortion due to coating unevenness are serious problems.

  By the way, the film thickness of the hard coat layer is generally about 1 to 2 μm when it is formed by coating on a smooth surface. On the other hand, for example, as in Patent Document 1, a hard coat layer is coated on a surface having an uneven shape like an optical filter for display in which a hard coat layer or the like is provided on a mesh-like electromagnetic shielding layer (conductive layer). In order to form a hard coat layer that covers the uneven shape and has high surface flatness, it is necessary to make the film thickness thicker. In addition, even in the case of coating on a smooth surface, a hard coat layer containing an additive such as a filler having a large particle size or an ultraviolet absorber can ensure surface flatness or have various functions. In some cases, a thicker film thickness is required to exhibit the above (for example, Patent Document 2).

JP 2009-37237 A JP 2010-99835 A

  In order to form a hard coat layer having a thick film as described above (in the present invention, also referred to as a thick film hard coat layer, which is a hard coat layer having a thickness of 3 μm or more), in general, a coating liquid is used more than usual. It is necessary to coat thickly, and the time until the coating layer dries may become longer. At this time, if there is a fine foreign matter that dissolves in the solvent of the coating solution on the surface of the substrate to be coated, the foreign matter itself is fine, so it does not become a defect as it is during the production line. In some cases, components eluted from foreign substances flow in the direction of inclination at locations where the substrate is greatly inclined (for example, between transport rolls, etc.), resulting in streak-like optical defects (streaky defects). Further, according to the study by the present inventors, when the viscosity of the coating liquid is increased in order to prevent streak-like defects, air is entrained during coating to generate bubble defects or uneven coating. It turns out that there is a case.

  Accordingly, an object of the present invention is a coating liquid for forming a thick hard coat layer, which can suppress the occurrence of streak-like defects and can suppress the occurrence of bubble-like defects and uneven coating. To provide liquid.

  Another object of the present invention is a hard coat film including a structure having a hard coat layer on a transparent substrate, and a method for producing a hard coat film with reduced streak-like defects, bubble-like defects, and coating unevenness And a hard coat film obtained by the method.

  Furthermore, an object of the present invention is an optical filter for display including a mesh-like conductive layer and a structure having a hard coat layer on the conductive layer, which reduces streak-like defects, bubble-like defects, and coating unevenness. Another object of the present invention is to provide a method for producing a display optical filter, and a display optical filter obtained by the method.

  The above object is a coating liquid for forming a hard coat layer having a thickness of 3 μm or more, comprising a resin composition and isobutyl alcohol as a solvent and a solvent A having a boiling point higher than that of isobutyl alcohol. The content is not less than the content of the solvent A, and the viscosity is 7 to 16 mPa · s.

  When forming a hard coat layer with a thickness of 3 μm or more, that is, a thick hard coat layer, the viscosity of the coating liquid is in the above range. While being able to suppress, it can make it difficult to produce coating nonuniformity. It has also been found that the use of isobutyl alcohol (also referred to as IBA) as a solvent for dissolving the resin composition can suppress the occurrence of the above-mentioned bubble defects. Although this factor is not clear, IBA was considered to have some antifoaming effect. However, if only IBA is used as the solvent, the drying speed of the coating solution is too fast, which causes coating unevenness. Therefore, it is necessary to contain solvent A having a boiling point higher than that of IBA. The boiling point of IBA is 107.9 ° C., and the boiling point of solvent A should be higher than this temperature. The boiling point of the solvent A is preferably 110 to 160 ° C, more preferably 120 to 150 ° C, particularly preferably 130 to 150 ° C.

Preferred embodiments of the coating liquid for forming a hard coat layer according to the present invention are as follows.
(1) Content of the said isobutyl alcohol is 23-33 mass% on the basis of the mass of a coating liquid. Thereby, it is possible to sufficiently exhibit the effect of suppressing the occurrence of bubble defects of isobutyl alcohol and to further suppress the occurrence of coating unevenness.
(2) The solvent A is propylene glycol monomethyl ether acetate (also referred to as PMA). PMA has a boiling point of 146 ° C. and is useful as the solvent A in the present invention.
(3) The mass ratio (IBA / solvent A) of the isobutyl alcohol (IBA) to the solvent A is 1/1 to 10/1. Thereby, the drying rate of a coating liquid becomes appropriate and it can further suppress that a coating nonuniformity arises.
(4) The resin composition contains a polymer having a weight average molecular weight of 6,000 to 200,000. By using the polymer in the resin composition, the viscosity and solid content of the coating solution can be optimized, and the effect of the coating solution of the present invention can be further exhibited.
(5) In (4), the resin composition further comprises a monomer having a molecular weight of 3000 or less and further having a polymerizable group. When the polymer is contained, the scratch resistance of the obtained hard coat layer may be lowered. By including the monomer in the resin composition, the scratch resistance of the hard coat layer can be improved. More preferably, the monomer having a polymerizable group has a molecular weight of 700 or less.
(6) In (5), the mass ratio (polymer / monomer) of the polymer to the monomer contained in the resin composition is 1/1 to 1/10. Thereby, the viscosity and solid content of the coating liquid can be further optimized, the effects of the coating liquid of the present invention can be sufficiently exhibited, and the scratch resistance of the resulting hard coat layer can be improved.
(7) The monomer is a monomer having three or more polymerizable groups in one molecule.
(8) The polymerizable group is a photopolymerizable group. For the formation of the hard coat layer, a photo-curing type is preferable because it can be cured in a short time and has excellent productivity.
(9) The polymerizable group is a group having an ethylenically unsaturated double bond.
(10) The group having an ethylenically unsaturated double bond is a (meth) acryloyl group.

  In addition, the above purpose is to apply the coating liquid of the present invention on the surface of the transparent substrate to form a coating layer (before drying), and to dry the coating layer (before drying), Alternatively, it is achieved by a method for producing a hard coat film comprising a step of forming a hard coat layer by curing after drying.

  By forming the hard coat layer using the coating liquid of the present invention, the hard coat layer can suppress the occurrence of streak-like defects, bubble-like defects and coating unevenness as described above even in the case of a thick-film hard coat layer. A film can be produced.

In the manufacturing method of the hard coat film of this invention, it is preferable that the film thickness ( _Dw ) from the transparent substrate surface of the said coating layer (before drying) is 25 micrometers or less. Thereby, the hard coat film by which generation | occurrence | production of the stripe-shaped defect was suppressed can be manufactured further. The film thickness (D _w ) of the coating layer (before drying) is set by the resin material content in the resin composition in the coating liquid and the film thickness of the hard coat layer to be formed. The film thickness (D _w ) of the coating layer (before drying) is further preferably 10 to 25 μm, particularly preferably 12 to 20 μm.

Further, the thickness from the transparent substrate surface of the hard coat layer (D _d) is preferably a 3 to 20 [mu] m. If it is a hard-coat layer of the film thickness of this range, the hard-coat film by which generation | occurrence | production of the stripe-shaped defect, the bubble-shaped defect, and the coating nonuniformity was suppressed can be manufactured.
The film thickness (D _d ) of the hard coat layer is further preferably 5 to 15 μm, and particularly preferably 6 to 12 μm.

  In addition, the above-described object is a process of forming a coating layer (before drying) by applying the coating liquid of the present invention on the conductive layer of a transparent substrate having a mesh-like conductive layer on one surface, and It is achieved by a method for producing an optical filter for display, comprising: drying the coating layer (before drying) or forming a hard coat layer by curing after drying.

  In order to cover the uneven shape of the mesh-like conductive layer formed on the surface of the transparent substrate and to form a hard coat layer with high surface flatness, a thick hard coat layer is formed by thickly coating the coating liquid. It is necessary. By forming the hard coat layer using the coating liquid of the present invention, it is possible to produce an optical filter for display in which the occurrence of streak-like defects, bubble-like defects, and coating unevenness is suppressed as described above.

The preferable aspect of the manufacturing method of the optical filter for displays of this invention is as follows.
(1) the coating layer having a thickness from the transparent substrate surface (before drying) (D _w), the ratio of average height (H) from the transparent substrate surface of the mesh of the conductive layer (D _w / H) is 6.5 or less. The film thickness (D _w ) of the coating layer (before drying) is set by the content of the resin material in the resin composition in the coating liquid and the film thickness of the hard coat layer to be formed. If the ratio of the film thickness (D _w ) to the average height (H) of the mesh-like conductive layer (D _w / H) is equal to or less than the above numerical value, the optical filter for display in which the generation of streak-like defects is further suppressed Can be manufactured. (D _w / H) is preferably from 4.5 to 6.5, more preferably 5.0-6.0.
(2) The difference (D _d −H) between the film thickness (D _d ) of the hard coat layer from the surface of the transparent substrate and the average height (H) of the mesh of the conductive layer from the surface of the transparent substrate. ) Is 1 to 5 μm. If the hard coat layer is formed on the mesh of the conductive layer within this range, it is possible to produce an optical filter for display in which generation of streak-like defects, bubble-like defects, and coating unevenness is further suppressed.

  The coating liquid for forming a hard coat layer of the present invention contains isobutyl alcohol as a solvent for dissolving the resin composition, and the viscosity is optimized within the above range. Even if the hard coat layer is formed, the occurrence of streak-like defects due to fine foreign matters is suppressed, and the occurrence of bubble-like defects and coating unevenness is also suppressed. Therefore, it can be said that the manufacturing method of the hard coat film using the coating liquid of this invention or the manufacturing method of the optical filter for a display is a method which can suppress the generation | occurrence | production of the said fault etc. and can manufacture a product with a high yield. The hard coat film or display optical filter obtained by the production method of the present invention can be said to be a product that can be produced at low cost because it is obtained with high quality and high yield.

It is a schematic sectional drawing which shows an example of the manufacturing method of the hard coat film using the coating liquid for hard-coat layer formation of this invention. It is a schematic sectional drawing which shows an example of the manufacturing method of the optical filter for displays using the coating liquid for hard-coat layer formation of this invention. It is a schematic sectional drawing which shows an example of the optical filter for displays of this invention.

  The coating liquid for forming a hard coat layer of the present invention is a coating liquid for forming a thick film hard coat layer having a thickness of 3 μm or more, and a resin composition and isobutyl alcohol (IBA) as a solvent for dissolving the resin composition. And a solvent A having a boiling point higher than that of IBA, and the content of isobutyl alcohol is not less than the content of the solvent A. The resin composition includes at least a resin material, and optionally includes additives such as a polymerization initiator. And the viscosity of the coating liquid is adjusted to 7-16 mPa * s. The viscosity can be adjusted by the type and content of the resin material, the type of solvent, and the like. In the present invention, the hard coat layer refers to a layer having a hardness of H or higher in a pencil hardness test specified by JIS K5600 (1999).

  The viscosity of the coating liquid for forming a general hard coat layer having a thickness of 1 to 2 μm is usually about 2 to 3 mPa · s. However, if the coating liquid is thickly applied to form a thick hard coat layer, the time until the coating layer dries may be long. At this time, as described above, the fine foreign matter that dissolves in the solvent of the coating solution at a position where the substrate is largely inclined, such as between the conveyance lines in the production line (as it is fine, it does not cause a defect). In some cases, the elution components flow in the tilt direction and cause streak-like defects. On the other hand, if the viscosity is too high in order to suppress the fluidity of the coating liquid, air may be involved at the time of coating, resulting in bubble defects or uneven coating. In the present invention, by setting the viscosity of the coating liquid within the above range, the fluidity of the coating liquid is suppressed, streak-like defects are prevented, and coating unevenness is less likely to occur. The viscosity of the coating liquid is preferably 11 to 16 mPa · s. Further, the use of IBA as a solvent suppresses the occurrence of bubble defects. As shown in Examples described later, the present inventors have found that IBA has an effect of suppressing bubble defects by examining the occurrence frequency of bubble defects using various solvents. Although this factor is not clear, it was considered that IBA has some defoaming effect due to properties such as surface tension. The content of IBA is preferably 23 to 33% by mass based on the mass of the coating solution. If it is this range, while being able to fully exhibit the effect which suppresses generation | occurrence | production of a bubble defect, it can make it difficult to produce coating nonuniformity more. As shown in Examples described later, when the IBA content is low, the effect of suppressing the occurrence of bubble defects is low, and when the IBA content is high, uneven coating tends to occur. The content of IBA is more preferably 26 to 30% by mass based on the mass of the coating solution.

  In the present invention, if only IBA is used as the solvent, the drying rate of the coating solution is too high, causing coating unevenness. Therefore, the solvent A having a boiling point higher than that of IBA is contained. Usually, the drying rate of the coating liquid can be suppressed by using a solvent having a high boiling point. Since the boiling point of IBA is 107.9 ° C., the boiling point of solvent A should be higher than this temperature. The boiling point of the solvent A is preferably 110 to 160 ° C, more preferably 120 to 155 ° C, and particularly preferably 130 to 150 ° C. Examples of the solvent A include propylene glycol monomethyl ether acetate (PMA) (boiling point: 146 ° C.), ethylene glycol monoethyl ether (boiling point: 135.6 ° C.), propylene glycol monomethyl ether (boiling point: 120 ° C.), propylene glycol mono Ethyl ether (boiling point: 132.2 ° C.), cyclohexanone (boiling point: 155.6 ° C.), 1-hexanol (boiling point: 157.1 ° C.), 2-methyl-1-pentanol (boiling point: 148.0 ° C.), Examples include toluene (boiling point: 110.6 ° C.), o-xylene (boiling point: 144.4 ° C.), m-xylene (boiling point: 139.1 ° C.), and the like. As the solvent A, propylene glycol monomethyl ether acetate (PMA) is particularly preferable. The mass ratio of IBA to solvent A (IBA / solvent A) is preferably 1/1 to 10/1. Thereby, the drying rate of a coating liquid becomes appropriate and it can further suppress that a coating nonuniformity arises. The mass ratio of IBA to solvent A (IBA / solvent A) is more preferably 1.5 / 1 to 7.5 / 1, and particularly preferably 3.5 / 1 to 6/1.

  In addition to the IBA and the solvent A, the coating liquid of the present invention may contain other solvents for the purpose of increasing the solubility according to the type of the resin material. Other solvents include hydrocarbons such as hexane, octane, cyclopentane and cyclohexane, alcohols such as 1-propanol, isopropanol and 1-butanol, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ethyl acetate, butyl acetate, Organic solvents such as esters such as isobutyl acetate can be mentioned.

  Moreover, in this invention, it is preferable that the resin material in the resin composition used for the coating liquid for hard-coat layer formation contains the polymer whose weight average molecular weight is 6000-200000. By using the polymer as a resin material, the viscosity and solid content of the coating liquid can be optimized, and the effect of the coating liquid of the present invention (suppression of occurrence of streaky defects and bubble defects, coating (Suppression of occurrence of unevenness in work) can be sufficiently exhibited. In the present invention, the “weight average molecular weight” of an acrylic compound refers to a value measured in terms of polystyrene using a gel permeation chromatography (GPC) method.

  The polymer contained in the resin material may be any polymer as long as it has an average molecular weight in the above range, and may or may not have a polymerizable group. Since the hardness as a hard-coat layer may fall when a weight average molecular weight is too large, as for a weight average molecular weight, 7000-80000 are still more preferable. These polymers may be composed of one kind or two or more kinds of polymers.

Examples of the polymer include poly (meth) acrylate methyl, poly (meth) acrylate butyl, poly (acrylonitrile / styrene), and poly ((meth) acrylate 2-hydroxymethyl / (meth) acrylic acid. Methyl), poly (2-hydroxymethyl (meth) acrylate / butyl (meth) acrylate), and copolymers of these resins and silicone resins,
Polyol compounds (for example, ethylene glycol, propylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butyl-1, Polyols such as 3-propanediol, trimethylolpropane, diethylene glycol, dipropylene glycol, polypropylene glycol, 1,4-dimethylolcyclohexane, bisphenol A polyethoxydiol, polytetramethylene glycol, the polyols and succinic acid, maleic acid Polyester polyols which are reaction products of polybasic acids such as itaconic acid, adipic acid, hydrogenated dimer acid, phthalic acid, isophthalic acid, terephthalic acid, etc., or their acid anhydrides, and the above-mentioned polyols and ε-capro Polycaprolactone polyols which are reaction products with kuton, reaction products of the above-mentioned polyols with the above polybasic acids or ε-caprolactone of these acid anhydrides, polycarbonate polyols, polymer polyols, etc.) and organic polyisocyanates (for example, , Tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane-4,4′-diisocyanate, dicyclopentanyl diisocyanate, hexamethylene diisocyanate, 2,4,4′-trimethylhexamethylene diisocyanate, 2,2′-4- Trimethylhexamethylene diisocyanate) and hydroxyl group-containing (meth) acrylates (for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxy Loxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, cyclohexane-1,4-dimethylol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol penta (meth) acrylate, And polyurethane (meth) acrylate, which is a reaction product of dipentaerythritol hexa (meth) acrylate, glycerin di (meth) acrylate, and the like. These compounds can be used alone or in combination. Commercially available products include Beamset 371 (Arakawa Chemical Industries), Macromonomer AA-6, AA-10, AS-6, AB-6, AA-10, AN-6S (above, manufactured by Toagosei Co., Ltd.), HCX-201-54 (manufactured by Adeka Corporation), Foret M-80 (manufactured by Soken Chemical Co., Ltd.) and the like can be mentioned.

  Further, when a polymer having a large weight average molecular weight as described above is used as the resin material in the resin composition in the hard coat layer forming coating liquid of the present invention, the scratch resistance is reduced as a function of the hard coat layer. Therefore, the resin composition preferably further includes a monomer having a molecular weight of 3000 or less and having a polymerizable group. The molecular weight of the monomer having the polymerizable group is preferably 700 or less, and more preferably 200 to 600. The molecular weight of the monomer may be a weight average molecular weight or a formula weight obtained from a chemical formula. In this case, the monomer may be an oligomer. By using the polymer and the monomer together, it is possible to optimize the viscosity and solid content of the hard coat layer to sufficiently exhibit the effects of the present invention, and to improve the scratch resistance of the hard coat layer.

  Further, the blending ratio of the polymer and the monomer in the resin composition is not particularly limited, and further, the viscosity and solid content of the coating liquid are optimized, and the effects of the coating liquid of the present invention are sufficiently exhibited. In order to improve the scratch resistance of the obtained hard coat layer, the mass ratio of the polymer to the monomer (polymer / monomer) is preferably 1/1 to 1/10, more preferably 1/3 to 1/7. preferable.

  The monomer is preferably a monomer having three or more polymerizable groups in one molecule from the viewpoint of reactivity, and the polymerizable group of the monomer may be either a thermally polymerizable group or a photopolymerizable group. The polymerizable group is preferably a photopolymerizable group in that it can be cured in a short time by ultraviolet irradiation and is excellent in productivity.

  The polymerizable group may be any group such as a group having an ethylenically unsaturated double bond or a cyclic ether group such as an epoxy group or an oxetane group. However, in terms of reactivity, an ethylenically unsaturated double bond may be used. And a (meth) acryloyl group is particularly preferable.

  Any monomer (or oligomer) having a polymerizable group (preferably 3 or more per molecule) may be used. For example, the monomer (or oligomer) having a (meth) acryloyl group may be a monomer or an oligomer composed of the same components as those exemplified in the above polymer, such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth). Acrylate, 4-hydroxybutyl (meth) acrylate, 2-ethylhexyl polyethoxy (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, phenyloxyethyl (meth) acrylate, tricyclodecane mono (meth) acrylate, Dicyclopentenyloxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, acryloylmorpholine, N-vinylcaprolactam, 2-hydroxy-3-phenyloxypropyl (meth) a Acrylate, o-phenylphenyloxyethyl (meth) acrylate, neopentyl glycol di (meth) acrylate, neopentyl glycol dipropoxy di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, tricyclodecane dimethylol Di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, nonanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate , Pentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tris [(meth) acryloxyethyl] isocyanurate (Meth) acrylate monomers such as ditrimethylolpropane tetra (meth) acrylate, bisphenol type epoxy resin such as bisphenol A type epoxy resin, bisphenol F type epoxy resin and bisphenol type epoxy (meth) acrylic acid ) (Meth) acrylate oligomers such as acrylate. These compounds can be used alone or in combination. In particular, it is preferable to mainly use hard polyfunctional monomers such as pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate.

  When a monomer having a photopolymerizable group is used as the resin material, it is preferable to add a photopolymerization initiator to the resin composition. As the photopolymerization initiator, any compound suitable for the properties of the resin material to be used can be used.

  For example, acetophenone such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1 Benzoin series such as benzyldimethyl ketal, benzophenone, 4-phenylbenzophenone, benzophenone series such as hydroxybenzophenone, thioxanthone series such as isopropylthioxanthone, 2-4-diethylthioxanthone, and other special ones include methylphenyl glyoxylate Etc. can be used. Particularly preferably, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1, Examples include benzophenone. These photopolymerization initiators are optionally selected from one or more known and commonly used photopolymerization accelerators such as a benzoic acid system such as 4-dimethylaminobenzoic acid or a tertiary amine system. Can be mixed and used at a ratio of Moreover, it can be used by 1 type, or 2 or more types of mixture of only a photoinitiator. In particular, 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals, Irgacure 184) is preferable.

  Generally the quantity of a photoinitiator is 0.1-10 mass% with respect to the resin material, Preferably it is 0.1-5 mass%.

  Furthermore, the resin composition in the coating liquid for forming a hard coat layer may contain a small amount of an ultraviolet absorber, an infrared absorber, an anti-aging agent, a paint processing aid, a colorant and the like. In particular, it is preferable to contain an ultraviolet absorber (for example, a benzotriazole-based ultraviolet absorber or a benzophenone-based ultraviolet absorber), whereby yellowing of the filter can be efficiently prevented. The amount is generally 0.1 to 10% by mass, preferably 0.1 to 5% by mass, based on the resin material.

  The coating liquid for forming a hard coat layer of the present invention is, for example, in a concentration containing the above-mentioned resin composition in the above-mentioned viscosity range in a solvent containing the above-mentioned IBA and solvent A using a conventionally known mixer or the like. It can be prepared by dissolving or dispersing.

  Next, a method for producing a hard coat film of the present invention (in the present invention, including a structure including a hard coat layer on a transparent substrate) and a display optical filter will be described with reference to the drawings.

[Method for producing hard coat film]
FIG. 1 is a schematic cross-sectional view showing an example of a method for producing a hard coat film using the hard coat layer forming coating solution of the present invention. In the production method of the present invention, first, the hard coat layer forming coating solution of the present invention is applied to the surface of the transparent substrate 12 to form a coating layer (before drying) 14w (FIG. 1A). ). Any conventionally known method may be used for coating. For example, it can be performed using a suitable coating apparatus such as a gravure coater, knife coater, slot die coater, roll coater, Meyer bar coater, blade coater and the like. At this time, since the coating liquid of the present invention is used, the coating is performed so as to form a hard coat layer having a thickness of 3 μm or more. Next, the hard coat layer 14d is formed by drying the coating layer (before drying) 14w, evaporating the solvent, and further curing as necessary (FIG. 1B). Drying may be performed at normal temperature or may be performed by heating as necessary. For curing, a suitable method can be used depending on the kind of the polymerizable group and the initiator. In the case of light curing, many light sources that emit light in the ultraviolet to visible range can be used as the light source. For example, ultra-high pressure, high pressure, low pressure mercury lamp, chemical lamp, xenon lamp, halogen lamp, mercury lamp, carbon arc lamp, incandescent lamp And laser light. The irradiation time cannot be determined unconditionally depending on the type of lamp and the intensity of the light source, but is about several seconds to several minutes. In order to accelerate curing, the laminate may be heated to 40 to 120 ° C. in advance and irradiated with ultraviolet rays or the like.

  Since the production method of the present invention uses the coating liquid of the present invention, even in the case of a thick film hard coat layer, a hard coat in which the occurrence of streaky defects, bubble defects and coating unevenness is suppressed as described above. A film can be produced.

In the method of manufacturing the hard coating film of the present invention, the thickness (D _w) from the coating layer (before drying) 14 w transparent substrate surface as shown in FIGS. 1 (a) but is not particularly limited, 25 [mu] m or less It is preferable that This is because if the film thickness (D _w ) is too large, the coating layer (before drying) 14 _w flows, and a streaky defect may occur in the obtained hard coat layer. If it is said film thickness ( _Dw ), the hard coat film by which generation | occurrence | production of the stripe-shaped fault was suppressed further can be manufactured. The film thickness (D _w ) of the coating layer (before drying) 14w is set by the content of the resin material in the coating liquid and the film thickness of the hard coat layer 14d to be formed. The film thickness (D _w ) of the coating layer (before drying) 14 _w is further preferably 10 to 25 μm, particularly preferably 12 to 20 μm.

Then, the film thickness of the transparent substrate 12 surface of the hard coat layer 14d of FIG. 1 (b) (D _d) is preferably 3 to 20 [mu] m. If it is a hard-coat layer of the film thickness of this range, the hard-coat film by which generation | occurrence | production of the stripe-shaped defect, the bubble-shaped defect, and the coating nonuniformity was suppressed can be manufactured. The film thickness (D _d ) of the hard coat layer is further preferably 5 to 15 μm, and particularly preferably 6 to 10 μm.

  As described above, the hard coat film of the present invention obtained by the production method of the present invention can be said to be a product that can be produced at low cost because it is obtained with high quality and high yield.

  In addition, in the manufacturing method of the hard coat film of this invention, what is necessary is just to form the hard-coat layer 14d on the surface of the above-mentioned transparent substrate 12, for example, the transparent substrate 12 like the manufacturing method of the optical filter for displays mentioned later. Another layer may be formed on the surface of the transparent substrate 12 opposite to the surface on which the hard coat layer 14d is formed, or on the surface of the hard coat layer 14d.

[Method for producing optical filter for display]
FIG. 2 is a schematic cross-sectional view showing an example of a method for producing a display optical filter using the hard coat layer forming coating solution of the present invention. In the production method of the present invention, first, the coating liquid for forming a hard coat layer of the present invention is applied on the conductive layer 23 of the transparent substrate 22 having the mesh-shaped conductive layer 23 on one surface, A layer (before drying) 24w is formed (FIG. 2A). The mesh-like conductive layer 23 may be formed by any method, for example, by a method described later. Any conventionally known method may be used for coating. For example, it can be performed using a suitable coating apparatus such as a gravure coater, knife coater, slot die coater, roll coater, Meyer bar coater, blade coater and the like. At this time, in order to cover the uneven shape of the mesh-like conductive layer 23 formed on the surface of the transparent substrate 22 and to form a hard coat layer having a high surface flatness, the coating liquid of the present invention is used. Coating is performed so as to be a thick hard coat layer having a thickness of 3 μm or more (as a thickness from the surface of the transparent substrate 22). Next, the coating layer (before drying) 24w is dried to evaporate the solvent, and if necessary, further hardened to form the hard coat layer 24d (FIG. 2B). Drying may be performed at normal temperature or may be performed by heating as necessary. For curing, a suitable method can be used depending on the kind of the polymerizable group and the initiator. In the case of light curing, many light sources that emit light in the ultraviolet to visible range can be used as the light source. For example, ultra-high pressure, high pressure, low pressure mercury lamp, chemical lamp, xenon lamp, halogen lamp, mercury lamp, carbon arc lamp, incandescent lamp And laser light. The irradiation time cannot be determined unconditionally depending on the type of lamp and the intensity of the light source, but is about several seconds to several minutes. In order to accelerate curing, the laminate may be heated to 40 to 120 ° C. in advance and irradiated with ultraviolet rays or the like.

  Since the manufacturing method of the present invention uses the coating liquid of the present invention, even in the case of a thick hard coat layer covering the uneven shape of the conductive layer 23, as described above, streaky defects, bubble defects and coating An optical filter for display in which the occurrence of unevenness is suppressed can be manufactured.

In the method of manufacturing an optical filter for display of the present invention is not particularly limited in the coating layer shown in FIGS. 2 (a) thickness of from (before drying) 24w transparent substrate 22 surface (D _w) The ratio (D _w / H) of the mesh of the conductive layer 23 to the average height (H) from the surface of the transparent substrate 22 is preferably 6.5 or less. This is because if the film thickness (D _w ) is too thick compared to the mesh height (H), the coating layer (before drying) 24 _w flows and streaky defects may occur in the resulting hard coat layer. If the film thickness (D _w ) is a thickness that satisfies the above (D _w / H), an optical filter for display in which the occurrence of streak-like defects is further suppressed can be produced. The film thickness (D _w ) of the coating layer (before drying) 24w is set by the content of the resin material in the coating liquid and the film thickness of the hard coat layer to be formed. (D _w / H) is preferably from 4.5 to 6.5, more preferably 5.0-6.0.

And the film thickness ( _Dd ) from the transparent base material 22 surface of the hard-coat layer 24d shown in FIG.2 (b), and the height (H) from the transparent base material 22 surface of the mesh of the conductive layer 23 The difference (D _d −H) is preferably 1 to 5 μm. If the hard coat layer is formed on the mesh of the conductive layer within this range, it is possible to produce an optical filter for display in which generation of streak-like defects, bubble-like defects, and coating unevenness is further suppressed.

  As described above, the optical filter for display obtained by the production method of the present invention can be said to be a product that can be produced at low cost because it is obtained with high quality and high yield.

  In the method for producing an optical filter for display of the present invention, a hard coat layer 24d may be formed on the conductive layer 23 formed on the surface of the transparent substrate 22 described above. As an example, on the surface of the transparent substrate 22 opposite to the surface on which the conductive layer 23 and the hard coat layer 24d are formed, between the transparent substrate 22 and the conductive layer 23, or on the surface of the hard coat layer 24d, Another layer may be formed.

[Optical filter for display]
The optical filter for display of the present invention is not particularly limited as long as the production method of the present invention is used. FIG. 3 is a schematic sectional view showing an example of the optical filter for display according to the present invention.

  As shown in FIG. 3, in the display optical filter 30, a mesh-like conductive layer 33 is formed over the entire surface of a rectangular transparent substrate 32. An intermediate layer may be formed between the transparent substrate 32 and the conductive layer 33 (not shown). A hard coat layer 34d is formed thereon, and a high refractive index layer 35 and a low refractive index layer 36 are further formed thereon as an antireflection layer. A near-infrared layer 37 and an adhesive layer 38 are formed on the other surface of the transparent substrate 32 on which the conductive layer 33 is formed. The optical filter 30 is placed on the glass substrate 31 via the adhesive layer 38. Used by sticking to. Although the high refractive index layer 35 and the low refractive index layer 36 may be omitted as the antireflection layer, it is preferable that an antireflection layer is formed as an optical filter in order to suppress reflection of external light. As shown in FIG. 3, the antireflection layer may be a layer combined with the high refractive index layer 35 and the low refractive index layer 36, or only the low refractive index layer 36.

  In order to conduct electricity from the conductive layer 33 to the outside, the optical filter 30 has a functional layer such as a hard coat layer around the optical filter removed by laser irradiation or the like to expose the conductive layer, or conductive adhesive. It includes a structure in which a tape is sandwiched between conductive layers and grounded to the outside (not shown).

  In the present invention, since the hard coat layer 34d is formed by the manufacturing method using the hard coat layer forming coating liquid of the present invention, the streaky defects, the bubble defects and the It can be said that the production of uneven coating is suppressed, the optical filter for display is obtained with high quality and high yield, and can be manufactured at low cost.

  In the manufacturing method of the hard coat film and display optical filter of the present invention, and the hard coat film and display optical filter of the present invention obtained by these methods, any object can be used as long as the object of the present invention can be achieved. Materials and processes may be used. A preferred embodiment will be described below.

[Transparent substrate]
The transparent substrate is generally a transparent plastic film. The material is not particularly limited as long as it is transparent (meaning “transparent to visible light”). Examples of plastic films include polyester [eg, polyethylene terephthalate (PET), polybutylene terephthalate], polymethyl methacrylate (PMMA), acrylic resin, polycarbonate (PC), polystyrene, triacetate resin, polyvinyl alcohol, polyvinyl chloride, poly Examples thereof include vinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane and the like. Among these, polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), etc. are highly resistant to loads during processing (heat, solvent, bending, etc.) and particularly highly transparent. preferable. In particular, PET is preferable because it has excellent processability. In addition, organic dyes contained in the near-infrared absorbing layer and the like are likely to be deteriorated in durability by receiving ultraviolet rays, but polyesters such as PET are preferable because they tend to absorb such ultraviolet rays. You may provide the easily bonding layer for improving the adhesiveness of each functional layer on the surface of a transparent base material. The easy-adhesion layer is, for example, a thermosetting resin such as a copolyester resin and a polyurethane resin, or a metal oxide fine particle such as SiO ₂ , ZrO ₂ , TiO ₂ , or Al ₂ O ₃ , preferably an average. What adjusted the refractive index by mix | blending metal oxide fine particles with a particle size of 1-100 nm is used.

  The thickness of the transparent substrate varies depending on the use of the optical filter and the like, but is generally 1 μm to 10 mm, 1 μm to 5 mm, and particularly preferably 25 to 250 μm.

[Conductive layer]
The mesh-like conductive layer is generally set to be 10Ω / □ or less, preferably in the range of 0.001 to 5Ω / □, particularly 0.005 to 5Ω / □. As the mesh-like conductive layer, metal fibers and metal-coated organic fiber metals made into a mesh, copper foil on a transparent film etched into a mesh and provided with openings, conductive on the transparent film And the like, in which a conductive ink is printed in a mesh shape.

  In the case of a mesh-shaped conductive layer, the mesh preferably has a wire diameter of 1 μm to 1 mm and an aperture ratio of 40 to 95% made of metal fibers and / or metal-coated organic fibers. A more preferable wire diameter is 10 to 500 μm, and an aperture ratio is 50 to 95%. When the wire diameter exceeds 1 mm in the mesh-like conductive layer, the electromagnetic wave shielding property is improved, but the aperture ratio is lowered and cannot be made compatible. If it is less than 1 μm, the strength as a mesh is lowered and handling becomes difficult. Further, when the aperture ratio exceeds 95%, it is difficult to maintain the shape as a mesh. When the aperture ratio is less than 40%, the light transmittance is reduced, and the amount of light from the display is also reduced. In addition, the aperture ratio of a mesh means the area ratio which the opening part occupies in the projection area of the said mesh. 1-15 micrometers is preferable and, as for the height from the transparent base material surface of the mesh of a conductive layer, 3-10 micrometers is more preferable.

  As the metal of the mesh-like conductive layer and the metal of the metal-coated organic fiber, copper, stainless steel, aluminum, nickel, titanium, tungsten, tin, lead, iron, silver, carbon or alloys thereof, preferably copper, Stainless steel and nickel are used.

  As the organic material for the metal-coated organic fiber, polyester, nylon, vinylidene chloride, aramid, vinylon, cellulose and the like are used.

  When a conductive foil such as a metal foil is subjected to pattern etching, copper, stainless steel, aluminum, nickel, iron, brass, or an alloy thereof, preferably copper, stainless steel, or aluminum is used as the metal of the metal foil.

  If the thickness of the metal foil is too thin, it is not preferable in terms of handleability and workability of pattern etching, and if it is too thick, it affects the thickness of the film obtained, and the time required for the etching process becomes long. The thickness is preferably about 1 to 200 μm.

  The shape of the etching pattern is not particularly limited, and examples thereof include a grid-like metal foil in which square holes are formed, and a punching metal-like metal foil in which circular, hexagonal, triangular or elliptical holes are formed. It is done. Further, the holes are not limited to those regularly arranged, and may be a random pattern. The area ratio of the opening portion on the projection surface of the metal foil is preferably 20 to 95%, more preferably 40 to 95%, and particularly preferably 60 to 95%.

  In addition to the above, as a mesh-like conductive layer, dots are formed on the film surface by a material soluble in a solvent, and a conductive material layer made of a conductive material insoluble in a solvent is formed on the film surface, A mesh-like conductive layer obtained by bringing the film surface into contact with a solvent to remove the dots and the conductive material layer on the dots may be used.

  A metal plating layer may be further provided on the conductive layer in order to improve conductivity. The metal plating layer can be formed by a known electrolytic plating method or electroless plating method. As the metal used for plating, it is generally possible to use copper, copper alloy, nickel, aluminum, silver, gold, zinc, tin or the like, preferably copper, copper alloy, silver, or nickel, In particular, it is preferable to use copper or a copper alloy from the viewpoint of economy and conductivity.

  Moreover, you may give anti-glare performance. When this anti-glare treatment is performed, a blackening treatment may be performed on the surface of the (mesh) conductive layer. For example, oxidation treatment of a metal film, black plating such as chromium alloy, application of black or dark ink, and the like can be performed.

[Antireflection layer]
Among the antireflection layers, the high refractive index layer is doped with ITO, ATO, Sb ₂ O ₃ , SbO ₂ , In ₂ O ₃ , SnO ₂ , ZnO, and Al in the resin component (preferably UV curable resin). It is preferable to use a layer (cured layer) in which conductive metal oxide fine particles (inorganic compounds) such as ZnO and TiO ₂ are dispersed. The metal oxide fine particles preferably have an average particle size of 10 to 10,000 nm, preferably 10 to 50 nm. In particular, ITO (especially having an average particle diameter of 10 to 50 nm) is preferable. The film thickness is generally in the range of 10 to 500 nm, preferably 20 to 200 nm.

  Of the antireflection layer, the low refractive index layer is composed of fine particles such as silica and fluororesin, preferably 10 to 40% by weight (preferably 10 to 30% by weight) of hollow silica resin component (preferably UV curable resin). A layer (cured layer) dispersed therein is preferable. The film thickness is generally in the range of 10 to 500 nm, preferably 20 to 200 nm. As the hollow silica, those having an average particle diameter of 10 to 100 nm, preferably 10 to 50 nm, and a specific gravity of 0.5 to 1.0, preferably 0.8 to 0.9 are preferable.

  As the resin component used for these antireflection layers, the same resin components as those for ordinary hard coat layers can be used. Generally, it is a thermosetting resin such as phenol resin, resorcinol resin, urea resin, melamine resin, epoxy resin, acrylic resin, urethane resin, furan resin, silicone resin, or ultraviolet curable resin. An ultraviolet curable resin is preferable from the viewpoint of excellent productivity. When an ultraviolet curable resin is used, it is used as an ultraviolet curable resin composition (consisting of an ultraviolet curable resin, a photopolymerization initiator, etc.). As the ultraviolet curable resin, the above-mentioned polymers, monomers and the like can be used.

  The visible light transmittance as a whole is preferably 85% or more together with the hard coat layer described above. Both the visible light transmittance of the high refractive index layer and the low refractive index layer are preferably 85% or more.

  When composed of the hard coat layer and the above two layers, for example, the total thickness of the hard coat layer is 5 to 20 μm, the thickness of the high refractive index layer is 50 to 150 nm, and the thickness of the low refractive index layer is 50 to 50 μm. It is preferable that it is 150 nm.

  The antireflection layer can be formed in the same manner as the hard coat layer described above. In this case, each layer of the hard coat layer and the antireflection layer may be applied and cured one by one, or all the layers may be applied and then cured together. In the case of continuous processing, the coating surface may be scratched unless it is cured after application of each layer. Therefore, it is preferable to coat and cure each layer one by one.

[Near-infrared absorbing layer]
The near-infrared absorbing layer formed on the other surface of the transparent substrate on which the conductive layer is formed is generally obtained by forming a layer containing a pigment or the like on the surface of the substrate film. The near-infrared absorbing layer can be obtained, for example, by applying a coating liquid containing the above-described pigment and binder resin, and if necessary, drying and curing. Alternatively, it can also be obtained by applying a coating solution containing the above-mentioned pigment and binder resin and simply drying it. When used as a film, it is generally a near-infrared cut film, such as a film containing a pigment or the like. The dye generally has an absorption maximum at a wavelength of 800 to 1200 nm. Examples include phthalocyanine dyes, metal complex dyes, nickel dithiolene complex dyes, cyanine dyes, squarylium dyes, polymethine dyes, Examples include azomethine dyes, azo dyes, polyazo dyes, diimonium dyes, aminium dyes, and anthraquinone dyes, and cyanine dyes, phthalocyanine dyes, and diimonium dyes are particularly preferable. These dyes can be used alone or in combination. Examples of the binder resin include thermoplastic resins such as acrylic resins.

  The near-infrared absorbing layer may be provided with a function of adjusting color tone by providing a neon emission absorbing function (neon cut function). For this purpose, a neon-emission absorption layer (neon cut layer) may be provided, but a neon-emission selective absorption dye may be included in the near-infrared absorption layer.

  Examples of selective absorption dyes for neon emission include cyanine dyes, squarylium dyes, anthraquinone dyes, phthalocyanine dyes, polymethine dyes, polyazo dyes, azurenium dyes, diphenylmethane dyes, and triphenylmethane dyes. it can. Such a selective absorption dye is required to have a selective absorption of neon emission near 585 nm and a small absorption at other visible light wavelengths, so that the absorption maximum wavelength is 575 to 595 nm and the absorption spectrum half width is What is 40 nm or less is preferable.

  Also, when combining multiple types of near-infrared or neon luminescent absorbing dyes, if there is a problem with the solubility of the dye, if there is a reaction between the dyes due to mixing, if there is a decline in heat resistance, moisture resistance, etc. All the near-infrared absorbing dyes need not be contained in the same layer, and may be contained in another layer.

  Further, as long as the optical properties are not greatly affected, coloring pigments, ultraviolet absorbers, antioxidants and the like may be further added.

  As near-infrared absorption characteristics, it is preferable that the transmittance of 850 to 1000 nm is 20% or less, and further 15%. Further, as the selective absorption, it is preferable that the transmittance at 585 nm is 50% or less. Especially in the former case, there is an effect of reducing the transmittance in a wavelength region where malfunction of a remote controller of a peripheral device is pointed out. In the latter case, an orange color having a peak at 575 to 595 nm is color reproducibility. This has the effect of absorbing the orange wavelength, thereby improving the redness and improving the color reproducibility. As for the film thickness of a near-infrared absorption layer, 0.5-50 micrometers is common.

[Adhesive layer]
As the transparent pressure-sensitive adhesive layer, any resin can be used as long as it has an adhesion function of adhering to the glass substrate. For example, an acrylic adhesive formed from an ethylene-vinyl acetate copolymer (EVA), an ethylene-methyl acrylate copolymer, butyl acrylate, a rubber adhesive, SEBS (styrene / ethylene / butylene / styrene) and TPE-based pressure-sensitive adhesives and adhesives mainly composed of a thermoplastic elastomer (TPE) such as SBS (styrene / butadiene / styrene) can also be used.

  The film thickness is generally in the range of 5 to 500 μm, particularly 10 to 100 μm. In general, the optical filter can be equipped by pressure-bonding the pressure-sensitive adhesive layer to a glass plate of a display.

The present invention will be described below with reference to examples.
1. Hard coat layer formation test [Examples 1-8, Comparative Examples 1-7]
(1) Preparation of coating liquid for forming hard coat layer In the following resin materials and photopolymerization initiator, as shown in Table 1, each solvent (isobutyl alcohol (IBA) and propylene glycol monomethyl ether acetate (PMA), methyl ethyl ketone (MEK) ), Isopropyl alcohol (IPA), cyclohexanone) were added in various addition amounts, and dissolved by stirring to prepare a coating solution.
・ Resin material:
Foret M-80 (manufactured by Soken Chemical Co., Ltd., weight average molecular weight of about 80,000 (GPC method (polystyrene conversion)): dipentaerythritol hexaacrylate ADPH (manufactured by Shin-Nakamura Chemical Co., Ltd.) = 1: 5 (solid content mass ratio)
・ Photopolymerization initiator:
Irgacure 184 (manufactured by Ciba Specialty Chemicals)); 2.0 mass% (solid content of resin material)

(2) Formation of hard coat layer Each of the coating solutions prepared above is applied to the surface of the conductive mesh of the electromagnetic wave shielding conductive layer mesh (line width 25 μm, pitch 200 μm, conductive mesh height 3.5 μm). a micro gravure using company made coater, coating layer ratio mesh height (H) of the thickness of (before _{drying) (D w) (D w} / H) is shown in Table 1 the value (See Fig. 2 (a)). The film thickness (D _w ) of the coating layer (before drying) was adjusted by the gravure roll engraving specifications and the roll rotation speed during coating. In addition, 100 m was coated with each coating solution. Thereafter, the coating layer (before drying) was dried at 70 ° C. for 30 seconds, and then cured with a high-pressure mercury lamp at a UV irradiation amount of 300 mJ / cm ^2. The hard coating layer having the film thickness (D _d ) shown in Table 1 Formed.

(3) Evaluation The appearance of the hard coat layer formed using each coating solution was visually inspected, and the number of bubble defects and streak defects between 100 m was measured. The case where any defect was 5 or less was evaluated as ◯, the case where any defect was 6 to 11 was evaluated as Δ, and the case where any defect was 12 or more was evaluated as ×. As for coating unevenness, the case where no unevenness was observed was indicated by ◯, the case where slight unevenness was observed was indicated by Δ, and the case where unevenness was clearly recognized was indicated by ×.

  As shown in Table 1, the hard coat layer using the coating liquid containing IBA of Examples 1 to 8 and PMA as the solvent A (IBA content ≧ PMA content) and having a viscosity of 7 to 16 mPa · s was evaluated for defects. In the coating unevenness evaluation, it was Δ or more. On the other hand, even if IBA and PMA are included, Comparative Example 1 with a viscosity of 5 mPa · s has many streak-like defects, and the defect evaluation is x, and Comparative Examples 2 and 3 with a viscosity of 18 mPa · s are bubble-like defects. The defect evaluation was x, and the coating unevenness evaluation was x.

  Furthermore, even if the viscosity was 14 mPa · s, Comparative Examples 4 to 7 in which the IBA content was less than the content of the solvent A had very many bubble defects, and the defect evaluation was x.

  Further, Example 8 in which the content of IBA was 23% by mass had slightly more bubble defects, and the defect evaluation was Δ. On the other hand, in Example 1 where the IBA content was 36% by mass, the coating unevenness evaluation was Δ. However, because the IBA content was high, the coating liquid drying rate was high and smoothing was difficult. It was thought that. Therefore, it was recognized that the content of IBA is preferably 23 to 33% by mass.

  In addition, this invention is not limited to the structure and Example of said embodiment, A various deformation | transformation is possible within the range of the summary of invention.

  According to the present invention, a high-quality hard coat film or an optical filter for display can be provided at a low cost.

12, 22, 32 Transparent base material 23, 33 Conductive layer 14w, 24w Coating layer (before drying)
14d, 24d, 34d Hard coat layer 30 Optical filter 31 Glass substrate 35 High refractive index layer 36 Low refractive index layer 37 Near-infrared absorbing layer 38 Adhesive layer

Claims (15)

A coating liquid for forming a hard coat layer having a thickness of 3 μm or more,
The resin composition includes isobutyl alcohol as a solvent and solvent A having a boiling point higher than that of isobutyl alcohol, the content of isobutyl alcohol is equal to or higher than the content of the solvent A, and the viscosity is 7 to 16 mPa · s. A coating liquid characterized by that.   The coating liquid according to claim 1, wherein the content of the isobutyl alcohol is 23 to 33% by mass based on the mass of the coating liquid.   The coating solution according to claim 1 or 2, wherein the solvent A is propylene glycol monomethyl ether acetate.   The coating liquid according to claim 1, wherein a mass ratio of the isobutyl alcohol (IBA) to the solvent A (IBA / solvent A) is 1/1 to 10/1.   The coating liquid according to any one of claims 1 to 4, wherein the resin composition contains a polymer having a weight average molecular weight of 6,000 to 200,000.   The coating liquid according to claim 5, wherein the resin composition further contains a monomer having a molecular weight of 3000 or less and having a polymerizable group.   The coating liquid according to claim 6, wherein a mass ratio (polymer / monomer) of the polymer to the monomer contained in the resin composition is 1/1 to 1/10. Applying the coating liquid according to any one of claims 1 to 7 on the surface of the transparent substrate to form a coating layer (before drying); and
A method for producing a hard coat film, comprising: drying the coating layer (before drying) or forming a hard coat layer by drying and then curing. The manufacturing method according to claim 8, wherein the coating layer (before drying) has a film thickness (D _w ) from the surface of the transparent substrate of 25 μm or less. The manufacturing method according to claim 8 or 9, wherein a film thickness (D _d ) of the hard coat layer from the surface of the transparent substrate is 3 to 20 µm.   The hard coat film manufactured by the manufacturing method of any one of Claims 8-10. The coating liquid of any one of Claims 1-7 is applied on the said conductive layer of the transparent substrate which has a mesh-shaped conductive layer on one surface, and a coating layer (before drying) is formed. And a step of forming the hard coat layer by drying the coating layer (before drying) or by curing after drying, and a method for producing an optical filter for display. The ratio (D _w / H) of the thickness (D _w ) of the coating layer (before drying) from the surface of the transparent substrate to the average height (H) of the mesh of the conductive layer from the surface of the transparent substrate is The manufacturing method according to claim 12, which is 6.5 or less. The difference (D _d -H) between the film thickness (D _d ) of the hard coat layer from the transparent substrate surface and the average height (H) of the mesh of the conductive layer from the transparent substrate surface, The manufacturing method according to claim 12 or 13, which is 1 to 5 µm.   The optical filter for displays manufactured by the manufacturing method of any one of Claims 12-14.

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