JP2016210039A - Hard coat film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard coat film which is excellent in scratch resistance, winding property and transparency, hardly causes poor appearance even when produced at high speed in order to enhance production efficiency, enhances productivity, and lowers a defective ratio.SOLUTION: There is provided a hard coat film which has a coating layer formed of a coating liquid containing a compound having a condensed polycyclic aromatic and an epoxy compound on at least one surface of a laminated polyester film, and has a hard coat layer on the coating layer, where a displacement amount of absolute reflectivity of the surface of the hard coat layer is 0.5% or less within a range of wavelength 500-600 nm.SELECTED DRAWING: None

Description

  The present invention relates to a hard coat film that can be suitably used for, for example, a capacitive touch panel member, and relates to a hard coat film having a good appearance.

  In recent years, the demand for touch panels has increased rapidly, and high efficiency in the production of touch panel members has been demanded. Although touch panels can be classified into various types, a capacitive touch panel has attracted particular attention in recent years. The capacitive touch panel is provided with an electrode layer, and there are cases using glass as a support and cases using a polyester film or the like. From the viewpoint of improving productivity through weight reduction, low cost, and roll-to-roll, there are an increasing number of film usage examples.

  In the production process of the transparent conductive layer, heat treatment is generally performed. For example, an ITO film is formed by a sputtering method, and then heat treatment at 150 ° C. may be performed in order to crystallize the ITO film. When a polyester film is used as the support, an ester cyclic trimer contained in the polyester may be deposited on the surface and become a coating defect. Therefore, a layer that does not precipitate this (hereinafter sometimes abbreviated as OLB layer) is required. A general hard coat film satisfies this characteristic, but has a drawback that the surface is smooth and has no roughness, the winding property is deteriorated, and a protective film is required. In this case, the cost for the protective film increases.

  On the other hand, a film having a surface roughened to obtain winding properties has a drawback that light is scattered on the surface and haze increases. Under such circumstances, with the recent growth of touch panels, improvement of transparency is also demanded, and a film having both winding property and transparency is demanded.

  In addition, as the touch panel becomes highly transparent, the appearance requirements have become stricter, and there is a demand to reduce coating defects that can be confirmed by interference unevenness. For this reason, it is necessary to coat with a uniform thickness to reduce the problem of interference unevenness due to the thickness difference. However, since the hard coat paint has a high viscosity, it is difficult to achieve a uniform thickness at high speed, and productivity is generally greatly reduced.

  In addition, the hard coat film is curled after heating, causing problems such as difficulty in processing such as laminating, and improvement is demanded.

JP2013-193285A JP 2011-11419 A JP 2013-97562 A JP 2013-249368 A

  This invention is made | formed in view of the said situation, The solution subject is a highly transparent film used suitably as a touchscreen, Comprising: It is excellent in abrasion resistance, winding property, and transparency, and raises production efficiency. Therefore, an object of the present invention is to provide a hard coat film in which appearance defects are difficult to see even when production is performed at high speed, productivity is increased, and the defect rate is reduced.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by a polyester film having a specific configuration, and have completed the present invention.

  That is, the gist of the present invention is that at least one side of a laminated polyester film has a coating layer formed from a coating solution containing a compound having a condensed polycyclic aromatic and an epoxy compound, and a hard layer is formed on the coating layer. A hard coat film having a coat layer, wherein the displacement of absolute reflectance on the surface of the hard coat layer is 0.5% or less in a wavelength range of 500 to 600 nm.

  According to the laminated polyester film of the present invention, the visibility is good even after undergoing severe conditions such as heat treatment for a long time, the appearance defect due to the hard coat is not noticeable, and the protective film is excellent because of its winding property. It is a polyester film that can be produced by roll-to-roll without being required, has low curl after heating, reduces the occurrence rate of defects in the subsequent process, and has excellent optical properties and visibility, and has high industrial value.

  In the present invention, a polyester film (hereinafter sometimes abbreviated as a film) is a film obtained by stretching and orienting a sheet melt-extruded from an extrusion die in accordance with a so-called extrusion method. The polyester constituting the film refers to a polyester obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), and the like.

  In the present invention, the polyester is obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Typical polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN) and the like.

  The polyester used in the present invention may be a homopolyester or a copolyester. In the case of a copolyester, it is a copolymer containing 30 mol% or less of the third component. Examples of the dicarboxylic acid component of the copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acids (for example, P-oxybenzoic acid). Or 2 or more types are mentioned, As a glycol component, 1 type, or 2 or more types, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1, 4- cyclohexane dimethanone neopentyl glycol, is mentioned.

  In the present invention, the outermost layer preferably contains 80% by weight or more of polyester having an ester cyclic trimer content of 0.5% by weight or less. When a polyester having an ester cyclic trimer content of more than 0.5% by weight is used, or when the content is less than 80% by weight, the resulting laminated polyester is kept at 150 ° C. for a long time. When used in severe processing conditions such as heat treatment, sputtering under high tension conditions, durability testing under high-temperature and high-humidity conditions, the film haze is greatly increased. After processing, it may not be suitable for optical members in terms of optical characteristics and visibility.

  The thickness of the outermost layer of the film of the present invention is usually 4 μm or more, preferably 5 μm or more, and more preferably 6 μm or more. When the thickness of the outermost layer is less than 4 μm, the ester cyclic trimer precipitation sealing effect of the outermost layer may be reduced.

  The total film thickness of the film of the present invention is usually in the range of 10 to 100 μm. When the total film thickness is less than 10μm, when forming the ITO film by sputtering method to form a transparent conductive film, the film strength is lost to the processing tension, wrinkles occur and the transparent conductive film is formed properly There is a fear that it cannot be done. Further, if it is 100 μm or more, the processing area at the time of sputtering is small due to the outer diameter limitation by the machine, and thus the productivity tends to be deteriorated.

  In the polyester layer of the film of the present invention, particles may be blended mainly for the purpose of imparting slipperiness and preventing scratches in each step. The kind of the particle to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness. Specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples of the particles include magnesium, kaolin, aluminum oxide, and titanium oxide. Further, the heat-resistant organic particles described in JP-B-59-5216, JP-A-59-217755 and the like may be used. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used. On the other hand, the shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as required.

  Although it does not specifically limit as an average particle diameter of the particle | grains mix | blended in a polyester film, Usually, 0.02-3 micrometers, Preferably it is 0.02-2.5 micrometers, More preferably, it is the range of 0.02-2 micrometers. It is. When particles having an average particle size of less than 0.02 μm are used, sufficient slipperiness cannot be imparted, so that the winding characteristics in the film production process tend to be inferior. On the other hand, when the average particle size exceeds 3 μm, the degree of roughening of the film surface becomes too large and the film haze may increase.

  Furthermore, the particle content in the polyester layer is usually in the range of 0.0005 to 0.5% by weight, preferably 0.001 to 0.3% by weight. When the particle content is less than 0.0005% by weight, the slipperiness of the film may be insufficient, resulting in poor appearance such as scratches during film processing. On the other hand, when adding over 0.5 weight%, the transparency of a film may be inadequate.

  In the present invention, the method of blending the particles with the polyester is not particularly limited, and a known method can be adopted. For example, it can be added at any stage of producing the polyester, but it is preferably added as a slurry dispersed in ethylene glycol or the like at the stage of esterification or before the start of the polycondensation reaction after completion of the transesterification reaction, The polycondensation reaction may proceed. Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a vented kneading extruder and a polyester raw material, or a blending of dried particles and a polyester raw material using a kneading extruder. It is done by methods.

  Moreover, in order to improve adhesiveness with a hard-coat layer, formation of an anchor layer is essential for the polyester film in this invention. Further, surface treatment such as corona treatment or plasma treatment may be performed.

  The formation of the anchor layer constituting the laminated polyester film of the present invention will be described. Regarding the anchor layer, it may be provided by so-called in-line coating, which treats the film surface during the process of forming a polyester film, or may adopt so-called off-line coating which is applied outside the system on the film once produced. .

  It is an essential requirement for the anchor layer to have a coating layer formed by coating a coating solution containing a compound having a condensed polycyclic aromatic and an epoxy compound.

  The in-line coating is not limited to the following, but for example, in the sequential biaxial stretching, the coating treatment can be performed particularly before the lateral stretching after the longitudinal stretching is finished. When an anchor layer is provided on a polyester film by in-line coating, the anchor layer can be applied simultaneously with film formation, and the anchor layer can be processed at a high temperature in the heat treatment step of the polyester film after stretching. Performances such as adhesion to various surface functional layers that can be formed on the layer and heat-and-moisture resistance can be improved. Moreover, when coating before extending | stretching, the thickness of an anchor layer can also be changed with a draw ratio, and compared with an off-line coating, uniform coating can be performed with a thin film. That is, a film suitable as a polyester film can be produced by in-line coating, particularly coating before stretching.

  For offline coding, conventionally known coating methods such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating, etc. can be used. Regarding the coating method, there is a description example in “Coating method” published by Yasuharu Harasaki in 1979. The drying conditions are not limited to the following, but heat treatment is usually performed at 50 to 120 ° C. for 30 to 60 seconds, preferably 70 to 100 ° C. for 30 to 60 seconds.

  Moreover, you may use together heat processing and active energy ray irradiation, such as ultraviolet irradiation, as needed. In addition, a conventionally well-known apparatus and an energy source can be used as an energy source for hardening by active energy ray irradiation. Moreover, 30-150 nm is preferable and, as for the thickness of an anchor layer, 50-100 nm is more preferable. If the thickness of the anchor layer is less than 30 nm, the adhesion with the hard coat layer tends to be poor. On the other hand, if it exceeds 150 nm, the appearance of the hard coat surface may be deteriorated.

  The laminated body of this invention has a hard-coat layer on the application layer of the above-mentioned polyester film. By having such a hard coat layer, scratches on the surface of the transparent substrate can be suppressed. Moreover, the low molecular component which precipitates from a bright base material (For example, when a transparent base | substrate is a transparent resin film which consists of polyester, the oligomer component of polyester, etc.) can be suppressed. In addition, it is preferable to apply a hard coat on both sides, so that curling of the film can be suppressed. In the present specification, the “hard coat layer” refers to a layer that uses # 0000 steel wool and is not damaged after 10 reciprocations with a 100 g weight.

  The film thickness (after drying) of each hard coat layer is preferably in the range of 0.1 to 10 μm, and more preferably in the range of 0.5 to 8 μm.

  Moreover, in this invention, in order to make winding property favorable, it is preferable that the dynamic friction coefficients of the front and back are 0.6 or less. If it is not less than 0.6, the winding property may be insufficient.

  In the present invention, from the viewpoint of workability, the heating curl is preferably 10 mm or less, and more preferably 5 mm or less. If it is 10 mm or more, there may be a problem that the film curls during heat processing and the running property is deteriorated.

  The hard coat layer is formed of a curable resin such as a thermosetting resin or a radiation curable resin as a main component. In the present invention, a radiation curable resin is preferable from the viewpoint of the hardness of the hard coat layer and the flatness of the obtained laminate, and an ultraviolet curable resin is particularly preferable.

  The hard coat layer in the present invention is preferably made of the following radiation curable resin as a main component. Here, “as a main component” means that it is 20% by mass or more, preferably 25% by mass or more, based on the mass of the hard coat layer.

  A radiation curable resin is a monomer, oligomer, or polymer that can be crosslinked and cured by radiation. As the radiation curable resin in the present invention, it is possible to increase the crosslink density after curing, from the viewpoint that the effect of improving the surface hardness can be increased, and the effect of improving the transparency can be increased. A polyfunctional (meth) acrylate compound such as a polyfunctional (meth) acrylate monomer, a polyfunctional (meth) acrylate oligomer, or a polyfunctional (meth) acrylate polymer is preferable. Here, “(meth) acrylate” represents acrylate and / or methacrylate.

  Such a polyfunctional (meth) acrylate compound is a compound containing a (meth) acryloyl group in the molecule, and preferably contains at least two (meth) acryloyl groups in the molecule. As a result, the crosslinking reaction of the radiation curable resin easily proceeds, and the effect of improving the surface hardness can be enhanced. In addition, the polyfunctional (meth) acrylate compound in this invention may contain other polymerizable functional groups other than a (meth) acryloyl group in a molecule | numerator. Here, the “(meth) acryloyl group” represents an acryloyl group and / or a methacryloyl group.

Specific examples of the polyfunctional (meth) acrylate compound containing at least two (meth) acryloyl groups in the molecule include, for example, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri ( (Meth) acrylate, trimethylolethane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, alkyl-modified dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Alkyl modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa Monomers such as (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate), melamine (meth) acrylate, and oligomers of about 2 to 20 mer composed of at least one of these, and polymer composed of at least one of these Can be mentioned. Such polyfunctional (meth) acrylate compounds may be used alone or in combination of two or more.

  The number of repeating units of the polyfunctional (meth) acryl oligomer / polymer is not particularly limited. For example, the number average molecular weight is preferably 150 to 1,000,000, preferably 1,000 to 500,000, and the effect of improving the coating appearance is enhanced. Can do. When the number average molecular weight is less than 150 or exceeds 1,000,000, the viscosity tends to be too low or too high, and the effect of improving the coating appearance tends to be low.

  Polyfunctional (meth) acrylate compounds containing at least two (meth) acryloyl groups in the molecule as described above are, for example, Aronics M-400, M-450, M-305, M-309, M-310, M-315, M-320, TO-1200, TO-1231, TO-595, TO-756 (above, manufactured by Toagosei), KAYARD D-310, D-330, DPHA, DPHA-2C (above, Nipponization) Such as Nikarac MX-302 (manufactured by Sanwa Chemical Co., Ltd.).

  The hard coat layer on each surface may be applied with the same paint or with another paint. When another paint is applied, if the difference in the heat shrinkage rate of the hard coat layer is large, the difference in the shrinkage rate of the hard coat layer is increased, and the heating curl may be deteriorated. Therefore, the difference in the main component amount of the coat layer in each layer is preferably within 10%.

  The hard coat layer preferably contains particles in order to develop antiblocking properties. The form of such particles is not particularly limited as long as the desired effect can be obtained, and may be organic particles or inorganic particles. Examples of the organic particles include organic polymer particles such as core-shell particles obtained by surface-treating silicone resin, crosslinked acrylic resin, crosslinked polyester, crosslinked polystyrene, and styrene resin with acrylic. Examples of inorganic particles include spherical silica particles, alumina particles, calcium carbonate particles, and the like. Among these, from the viewpoint that transparency can be maintained, those having a refractive index difference from the binder resin of 0 to 0.05 or less can be suitably used.

  Moreover, when the average particle diameter of the particles is 0.01 to 1 μm, the handling property is excellent and the transparency is more easily maintained. From this viewpoint, the average particle size is more preferably 0.5 μm or less, and particularly preferably 0.4 μm or less.

  The content of the particles in the hard coat layer is usually 0.1 to 80% by mass on the basis of the mass of the hard coat layer, and if it is within this range, the handling property is excellent and the transparency is more easily maintained. Become. From this viewpoint, the content is more preferably 1.0% by mass or more, and particularly preferably 5.0% by mass or more.

  In the hard coat layer, the curable composition may further contain a radical polymerization initiator. Examples of the radical polymerization initiator include a compound that generates active radical species by radiation (light) irradiation (radiation (light) polymerization initiator), a compound that thermally generates active radical species (thermal polymerization initiator), and the like. Can be mentioned. If necessary, a radiation (light) polymerization initiator and a thermal polymerization initiator can be used in combination.

  The radiation (photo) polymerization initiator is not particularly limited as long as it can be decomposed by light irradiation to generate radicals to initiate polymerization. For example, acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2 , 2-dimethoxy-1,2-diphenylethane-1-one, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy Roxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propane -1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2 , 4,6-trimethylbenzoyldiphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) and the like.

  As a commercial item of a radiation (photo) polymerization initiator, for example, Ciba Specialty Chemicals Co., Ltd. trade name: Irgacure 127, 184, 369, 651, 500, 819, 907, 784, 2959, CGI 1700, CGI 1750, CGI1850, CG24-61, Darocur 1116, 1173, manufactured by BASF Inc. Product name: Lucirin TPO, manufactured by UCB Corp. Product name: Ubekrill P36, manufactured by Fratteri Lamberti, Inc. Product names: Ezacure KIP150, KIP65LT, KIP100F, KT37, KT55, KTO46 , KIP75 / B and the like.

  Examples of the thermal polymerization initiator include peroxides and azo compounds. Specific examples include benzoyl peroxide, t-butyl-peroxybenzoate, and azobisisobutyronitrile. .

  The content of the radical polymerization initiator in the hard coat layer is preferably 0.01 to 10% by mass and more preferably 0.1 to 5% by mass based on the mass of the hard coat layer. If it is less than 0.01% by mass, the hardness may be insufficient, and if it exceeds 10% by mass, the inside may not be sufficiently cured.

  The curable composition may contain other polymerizable compounds. Examples of the polymerizable compound include vinyl compounds.

  Examples of the vinyl compounds include divinylbenzene, ethylene glycol divinyl ether, diethylene glycol divinyl ether, and triethylene glycol divinyl ether.

  The curable composition may further contain other additives. Examples of the additives include antistatic agents, leveling agents, ultraviolet absorbers, antioxidants, light stabilizers, pigments, dyes, filling agents, dispersants, plasticizers, surfactants, thixotropic agents, etc. Can do.

  As the leveling agent, it is preferable to appropriately select and use a silicone-based or fluorine-based leveling agent. Examples of the silicone leveling agent include polydimethylsiloxane, polymethylalkylsiloxane, polyether-modified polydimethylsiloxane, polysiloxane having a (meth) acryl group, and the like.

  Examples of the ultraviolet absorber include benzotriazole-based, benzophenone-based, salicylic acid-based, and cyanoacrylate-based ultraviolet absorbers.

  Examples of the antioxidant include hindered phenol-based, sulfur-based, and phosphorus-based antioxidants.

  Examples of the light stabilizer include hindered amine light stabilizers.

  Each of these additives may be used alone or in combination of two or more. Moreover, as content of these other additives, 10 mass% or less is preferable in a total solid, and 3 mass parts or less are preferable.

  The curable composition is usually used after being diluted with a solvent in order to adjust the viscosity (coating property) and the thickness of the coating film. As a viscosity of the said curable composition, it is 0.1-50,000 mPa * second / 25 degreeC normally, Preferably it is 0.5-10,000 mPa * second / 25 degreeC.

  Examples of the solvent include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone cyclopentanone and cyclohexanone; esters such as ethyl acetate and butyl acetate; alcohols such as isopropyl alcohol and ethyl alcohol; benzene, toluene, xylene and methoxybenzene Aromatic hydrocarbons such as 1,2-dimethoxybenzene; phenols such as phenol and parachlorophenol; halogenated hydrocarbons such as chloroform, dichloromethane, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, and chlorobenzene It is done. These solvents can be used alone or in combination of two or more.

  The content of the solution is preferably 70% by mass or less, more preferably 30% by mass or more and 60% by mass or less.

  In the present invention, the hard coat film preferably has a haze of 2% or less. If it exceeds 2%, it may affect the beauty of characters when used in a capacitance type film.

  In the present invention, it is an essential condition that the amount of displacement of the absolute reflectance of the hard coat surface of the hard coat film is 0.5% or less in the wavelength range of 500 to 600 nm. If it is larger than 0.5%, it is easy to see the defect of interference, the appearance defect rate increases, and the productivity decreases.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. The measuring method used in the present invention is as follows.

(1) Measurement of intrinsic viscosity of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. It was dissolved and measured at 30 ° C.

(2) Measurement of average particle diameter of particles contained in polyester raw material (d50)
The particle size was measured by a sedimentation method based on Stokes' resistance law using a centrifugal sedimentation type particle size distribution analyzer SA-CP3 manufactured by Shimadzu Corporation.

(3) Measuring method of amount of ester cyclic trimer contained in polyester raw material About 200 mg of polyester raw material is weighed and dissolved in 2 ml of a mixed solvent of chloroform / HFIP (hexafluoro-2-isopropanol) ratio 3: 2. . After dissolution, add 20 ml of chloroform, and then add 10 ml of methanol little by little. The precipitate is removed by filtration, and the precipitate is further washed with a mixed solvent having a chloroform / methanol ratio of 2: 1. The filtrate / washing solution is collected, concentrated by an evaporator, and then dried. After the dried product was dissolved in 25 ml of DMF (dimethylformamide), this solution was supplied to liquid chromatography (manufactured by Shimadzu Corporation: LC-7A) to determine the amount of ester cyclic trimer in DMF. Divided by the amount of the polyester raw material dissolved in the / HFIP mixed solvent to obtain the amount of ester cyclic trimer (weight%). The amount of ester cyclic trimer in DMF was determined from the peak area ratio between the standard sample peak area and the measured sample peak area (absolute calibration curve method).

  The standard sample was prepared by accurately weighing the pre-sorted ester cyclic trimer and dissolving it in DMF accurately weighed. The concentration of the standard sample is preferably in the range of 0.001 to 0.01 mg / ml.

The conditions of the liquid chromatograph were as follows.
Mobile phase A: Acetonitrile Mobile phase B: 2% acetic acid aqueous solution Column: “MCI GEL ODS 1HU” manufactured by Mitsubishi Chemical Corporation
Column temperature: 40 ° C
Flow rate: 1 ml / min Detection wavelength: 254 nm

(4) Measurement of average particle diameter of particles contained in anchor layer The anchor layer was observed using TEM (H-7650 manufactured by Hitachi, accelerating voltage 100 V), and the average value of the particle diameters of 10 particles was averaged. The particle size was taken.

(5) Measurement of anchor layer thickness The coated surface was dyed with RuO4 and embedded in an epoxy resin. Thereafter, the section prepared by the ultrathin section method was stained with RuO4, and the cross section of the coating layer was measured using TEM (H-7650 manufactured by Hitachi, accelerating voltage 100 V).

(6) Thickness of laminated polyester and hard coat layer A film piece was fixed and molded with an epoxy resin, then cut with a microtome, and the cross section of the film was observed with a transmission electron micrograph. Two of the cross-sections are observed in parallel with the film surface, and the interface is observed by light and dark. The distance between the two interfaces and the film surface was measured from 10 photographs, and the average value was defined as the laminated thickness.

(7) Refractive index of hard coat layer The refractive index was calculated using an Abbe refractometer manufactured by Atago Optical Co., Ltd. The refractive index was measured at 23 ° C. using sodium D line.

(8) Measurement of film haze The film haze was measured for the sample film according to JIS-K-7136 using a haze meter “HM-150” manufactured by Murakami Color Research Laboratory.

(9) Friction coefficient A film is pasted on a smooth glass plate having a width of 10 mm and a length of 100 mm, and a film cut out to a width of 18 mm and a length of 120 mm is pressed against a metal pin having a diameter of 8 mm. The frictional force was measured by sliding in the longitudinal direction of the plate at a load of 30 g and 40 mm / min, and the friction coefficient at the point of sliding by 10 mm was evaluated as the dynamic friction coefficient. When the coefficient of dynamic friction is 0.8 or more, the slipperiness may be poor, and is preferably 0.7 or less, more preferably 0.6 or less. In addition, when the value is μd> 1.0, it is difficult to accurately determine the value. The measurement was performed in an atmosphere of room temperature 23 ± 1 ° C. and humidity 50 ± 0.5% RH.

(10) Scratch resistance of steel wool (SW) Scratch of the coated film surface tested 10 times with # 0000 steel wool loaded with 100g load using a Gakushin type abrasion resistance tester manufactured by Tester Sangyo Co., Ltd. The state was evaluated visually.
○: When there are fewer than 10 scratches ×: When there are 10 or more scratches

(11) Absolute reflectance In advance, a black tape (vinyl tape VT-50 manufactured by Nichiban Co., Ltd.) is pasted on the measurement back surface of the polyester film, and a spectrophotometer (UV-visible spectrophotometer V-570 manufactured by JASCO Corporation) and automatic absolute Using a reflectivity measuring device AM-500N), a synchronous mode, an incident angle of 5 °, an N polarization, a response Fast, a data collection interval of 1.0 nm, a bandwidth of 10 nm, a scanning speed of 1000 m / min, and a coating layer surface of a wavelength range of 500 An absolute reflectance of ˜600 nm was measured and evaluated.
○: The displacement amount of the reflectance of 500 to 600 nm is within 0.5%. ×: The displacement amount of the reflectance of 500 to 600 nm exceeds 0.5%.

(12) Heating curl The sample film was cut into 5 cm x 5 cm, heated at 150 degrees x 90 minutes, the surface that was lifted was the top, the film was placed on a horizontal desk, the height of each corner was measured, and the average Values were measured and evaluated.

(13) Appearance inspection of coated film The surface opposite to the hard coat surface of the film coated with the hard coat was painted with black magic. This is done to make it easier to see the defects on the hard coat surface. Visual inspection was performed under a three-wavelength light.
○: Neither interference interference nor streaks can be confirmed ×: Either interference interference or streaks can be confirmed

(14) Film visibility evaluation method after transparent conductive film lamination (practical property substitution evaluation)
In the laminated polyester film, a sintered body material of 95% indium oxide and 5% by weight tin oxide in an atmosphere of 0.4 Pa composed of 95% argon gas and 5% oxygen gas is provided on the opposite surface of the hard coat layer. An ITO film (transparent conductive thin film) having a thickness of 25 nm was formed by the reactive sputtering method used. The ITO film was crystallized by heat treatment at 150 ° C. for 1 hour. The transparency and visibility of the obtained film were determined according to the following criteria.
<Criteria>
○: Transparency / Visibility, good (no problem for practical use)
×: Transparency / visibility poor (practical problem level)

(15) Blocking resistance Each sample was cut into 10 cm square to prepare two sample pieces. One sample piece is fixed to the mirror surface of the SUS plate so that the hard coat layer is facing, and another sample piece is overlaid so that the hard coat layer surfaces are in contact with each other, and then the 5 kg roller is reciprocated five times. Crimped and subjected to blocking test. A load (area 25 cm 2) was applied obliquely from the 45 ° direction, slip was generated between the hard coat layer surfaces, and the load was measured when the stacked test specimens later moved in the load direction.
○: When the load for moving the test piece is 10 kg or less ×: When the load for moving the test piece is heavier than 10 kg

<Manufacture of polyester>
[Method for producing polyester (A1)]
Using 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol as starting materials, 0.09 parts by weight of magnesium acetate tetrahydrate as a catalyst is placed in the reactor, the reaction start temperature is set to 150 ° C., and the methanol is distilled off gradually. The reaction temperature was raised to 230 ° C. after 3 hours. After 4 hours, the transesterification reaction was substantially terminated. After adding 0.04 part by weight of ethyl acid phosphate to this reaction mixture, 0.04 part by weight of antimony trioxide was added, and a polycondensation reaction was carried out for 4 hours. That is, the temperature was gradually raised from 230 ° C. to 280 ° C. On the other hand, the pressure was gradually reduced from normal pressure, and finally 0.3 mmHg. After the start of the reaction, the reaction was stopped at a time corresponding to an intrinsic viscosity of 0.63 due to a change in stirring power of the reaction tank, and the polymer was discharged under nitrogen pressure. The obtained polyester (A1) had an intrinsic viscosity of 0.65 and an ester cyclic trimer content of 0.97% by weight.

[Production method of polyester (A2)]
Polyester (A1) is pre-crystallized at 160 ° C. in advance and then solid-phase polymerized in a nitrogen atmosphere at a temperature of 220 ° C. to obtain a polyester having an intrinsic viscosity of 0.75 and an ester cyclic trimer content of 0.46% by weight. (A2) was obtained.

[Production method of polyester (A3)]
In the polyester (A1) production method, after adding 0.04 part by weight of ethyl acid phosphate, 0.2 part by weight of silica particles dispersed in ethylene glycol having an average particle diameter of 1.6 μm and 0.04 part of antimony trioxide are added. A polyester (A3) was obtained using the same method as the production method of the polyester (A1) except that the polycondensation reaction was stopped at a time corresponding to an intrinsic viscosity of 0.65 by adding parts by weight. The obtained polyester (A3) had an intrinsic viscosity of 0.65 and an ester cyclic trimer content of 0.82% by weight.

Examples of compounds constituting the anchor layer are as follows.
(Example compounds)
・ Polyester resin (condensed polycyclic aromatic compound): (I)
Water dispersion of polyester resin copolymerized with the following composition: Monomer composition: (acid component) 2,6-naphthalenedicarboxylic acid / 5-sodium sulfoisophthalic acid / (diol component) ethylene glycol / diethylene glycol = 92/8/80 / 20 (mol%)

・ Acrylic resin (II)
In the presence of alkoxy polyethylene glycol methacrylate as a reactive emulsifier, copolymerization was carried out mainly with acrylic acid alkyl ester, methacrylic acid alkyl ester, methacrylic acid, N-methylolacrylamide, glass transition point 50 ° C., acid value 14 mgK
OH, acrylic resin with an average particle size of 0.05 μm

Epoxy compound: (III) Denacol EX-521 (manufactured by Nagase ChemteX), which is polyglycerol polyglycidyl ether
・ Oxazoline compounds: (IV)
Acrylic polymer Epocros WS-500 having an oxazoline group and a polyalkylene oxide chain (manufactured by Nippon Shokubai, containing about 38% by weight of 1-methoxy-2-propanol solvent)
Melamine compound: (V) Hexamethoxymethylmelamine Particles: (VI) Silica sol with an average particle size of 65 nm

Examples of compounds constituting the hard coat layer are as follows (examples of compounds)
・ Hard coat main agent (α)
M-402 (DPHA-based dipentaerythritol penta ratio made by Toa Gosei 30-40% containing polyfunctional acrylate compound containing acryloyl group)
・ Particle (β1)
Reactive silica with an average particle size of 20 nm (JGC Catalysts Conversion DP1039SIV)
・ Particle (β2)
Acrylic particles with an average particle size of 500 m / initiator (σ)
Irugacure127 (Ciba Japan)

Production Example 1
Two of the above-mentioned polyesters (A2) and (A3) mixed at a ratio of 85% by weight and 15% by weight are used as the raw material for the surface layer, and 100% by weight of the polyester (A1) is used as the raw material for the intermediate layer. Each was supplied to an extruder, melted at 285 ° C., and then on a casting drum cooled to 40 ° C., in two types and three layers, the thickness composition ratio of surface layer: intermediate layer: surface layer was 6: 11: 6 Co-extruded and cooled and solidified to obtain a non-oriented sheet.

Example 1:
The film obtained in Production Example 1 is stretched 3.4 times in the longitudinal direction at a film temperature of 85 ° C. using the roll peripheral speed difference, and then shown in Table 1 below on both sides of the longitudinally stretched film. The anchor layer is applied so that the film thickness after heat treatment is 0.1 μm, guided to a tenter, stretched 4.3 times at 120 ° C. in the transverse direction, heat treated at 225 ° C., and then the film is placed on a roll A laminated polyester film having a thickness of 23 μm was obtained. Next, on the coated layer on one side of the prepared polyester film (hereinafter referred to as “A-side”), the coating solutions shown in Table 1 and Table 2 below are diluted with MIBK and offline so that the coating thickness after drying and curing is 2 μm. Then, after applying by a reverse gravure coating method, heat treatment was performed at 90 ° C. for 60 seconds, and then irradiation was performed at 300 mJ / cm ² with a high-pressure mercury lamp irradiation apparatus (EUV482A: manufactured by Celitec). On the opposite side (hereinafter referred to as B side) of the obtained film, the coating solutions shown in Table 1 and Table 2 below are diluted with MIBK, and reversely applied offline so that the coating thickness after drying and curing is 2 μm. Table 3 below shows the characteristics of heat treatment at 90 ° C. for 60 seconds, followed by irradiation at 300 mJ / cm ² with a high-pressure mercury lamp irradiation device (EUV482A: manufactured by Celitec) after coating by the gravure coating method.

Example 2:
A polyester film was obtained in the same manner as in Example 1, except that the thickness of the anchor layers on both sides was changed to 0.1 μm in Example 1. The properties of the obtained film are shown in Table 3 below.

Example 3:
In Example 1, a polyester film was obtained in the same manner as in Example 1 except that the A-side hard coat layer was changed to the hard coat liquid 2 shown in Tables 1 and 2. The properties of the obtained film are shown in Table 3 below.

Example 4:
In Example 1, the hard coat layer on the A and B sides was changed to the hard coat solution 3 shown in Tables 1 and 2 and the thickness of the hard coat layer was changed to 0.5 μm. A polyester film was obtained by this method. The properties of the obtained film are shown in Table 3 below.

Comparative Example 1:
In Example 1, the same method as in Example 1 was applied except that the hard coat layer on the A side was changed to the hard coat solution 3 shown in Tables 1 and 2 and the thickness of the hard coat layer was changed to 0.5 μm. A polyester film was obtained. The properties of the obtained film are shown in Table 3 below.

Comparative Example 2:
In Comparative Example 1, a polyester film was obtained in the same manner as in Example 1 except that the A-side hard coat layer was changed to the hard coat liquid 4 shown in Tables 1 and 2. The properties of the obtained film are shown in Table 3 below.

Comparative Example 3:
In Comparative Example 2, a polyester film was obtained in the same manner as in Example 1 except that the hard coat layer on the B surface was changed to the hard coat liquid 4 shown in Tables 1 and 2. The properties of the obtained film are shown in Table 3 below.

Comparative Example 4:
In Example 1, a polyester film was obtained in the same manner as in Example 1 except that the A-side anchor layer was changed to the anchor liquid 2 shown in Tables 1 and 2. The properties of the obtained film are shown in Table 3 below.

Comparative Example 5:
In Example 3, a polyester film was obtained in the same manner as in Example 1 except that the A-side anchor layer was changed to the anchor liquid 2 shown in Tables 1 and 2. The properties of the obtained film are shown in Table 3 below.

Comparative Example 6:
In Example 4, a polyester film was obtained in the same manner as in Example 1 except that the A-side anchor layer was changed to the anchor liquid 2 shown in Tables 1 and 2. The properties of the obtained film are shown in Table 3 below.

Comparative Example 7:
In Example 1, a polyester film was obtained in the same manner as in Example 1 except that the coating thickness of the A-side anchor layer was changed to 0.15 μm. The properties of the obtained film are shown in Table 3 below.

Comparative Example 8:
In Example 1, a polyester film was obtained in the same manner as in Example 1 except that the coating thickness of the A-side anchor layer was changed to 0.02 μm. The properties of the obtained film are shown in Table 3 below.

  The hard coat film of the present invention can be suitably used as, for example, a capacitive touch panel member.

Claims (2)

A hard coat film having a coating layer formed from a coating liquid containing a compound having a condensed polycyclic aromatic and an epoxy compound on at least one surface of a laminated polyester film, and having a hard coat layer on the coating layer. A hard coat film having a displacement of absolute reflectance on the surface of the hard coat layer of 0.5% or less in a wavelength range of 500 to 600 nm. The hard coat film according to claim 1, wherein the hard coat film has a haze of 2% or less, and the hard coat layer has a refractive index of 1.4 to 1.5.