JP2009191188A - Curable coating material composition, cured coating film thereof, scratch-resistant resin plate and surface window protection plate of portable information terminal using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable coating material composition for forming a cured coating film having a high hardness, its cured coating film, a scratch-resistant resin plate and a display window protecting plate of a portable information terminal using the same. <P>SOLUTION: The curable coating material composition includes hafnium, a carboxylic acid containing a double bond in the molecule and a polyfunctional (meth)acrylate compound. The cured coating film is obtained by curing the curable coating material composition. The scratch-resistant resin plate is obtained by forming a cured coating film obtained by curing the curable coating material composition on the surface of a resin substrate. The surface window protecting plate of a portable information terminal includes the scratch-resistant resin plate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a curable coating composition suitable as a display window protection plate for a portable information terminal, a cured film thereof, a scratch-resistant resin plate, and a display window protection plate for a portable information terminal using the same.

  Recently, mobile phones such as mobile phones and PHS (Personal Handy-phone System) have become popular with the Internet, and in addition to simple voice transmission functions, mobile information has a function to display text information and image information. Widely used as a terminal. In addition to such portable telephones, PDAs (Personal Digital Assistants) that have Internet functions and e-mail functions in addition to functions such as address books are also widely used.

  These portable information terminals display character information and image information by a method such as liquid crystal or EL (electroluminescence), but the display window is made of a transparent resin as a protective plate. In general, methacrylic resin plates are preferably used from the viewpoint of transparency (see, for example, Patent Documents 1 to 3). In order to prevent the surface from being scratched, this protective plate has been proposed to be provided with a cured film having scratch resistance (hard coat property) with a curable coating. A compound having at least two (meth) acryloyloxy groups therein, that is, a compound containing a polyfunctional (meth) acrylate has been mainly studied (see the patent document).

  However, the conventionally proposed display window protection plate of a portable information terminal has a problem that the hardness of the cured coating (pencil hardness) is not sufficient. With a cured film having insufficient hardness, desired scratch resistance cannot be obtained.

  On the other hand, Patent Document 4 describes a hard film having a cured body layer obtained by curing a sol composition containing hafnia sol, (meth) acrylic acid, and the like. According to this document, this hard film is described as having high hardness, and a coating solution prepared by mixing a predetermined hafnia sol containing formic acid or oxalic acid and acrylic acid is applied to the surface of the polycarbonate substrate and cured. I am letting.

  However, even with such a cured film, sufficient hardness is not obtained at present, and development of a curable coating composition capable of forming a cured film with higher hardness is desired.

Japanese Patent Laid-Open No. 2002-6676 JP 2004-143365 A JP 2004-299199 A JP 2005-336466 A

  An object of the present invention is to provide a curable coating composition capable of forming a cured film having high hardness, a cured film thereof, a scratch-resistant resin plate, and a display window protection plate of a portable information terminal using the same. That is.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found a solution means having the following constitution and have completed the present invention.
(1) A curable coating composition comprising hafnium, a carboxylic acid having a double bond in the molecule, and a polyfunctional (meth) acrylate compound.
(2) The curable coating composition according to (1) above, wherein the sol composition containing hafnium and a carboxylic acid having a double bond in the molecule is mixed with the polyfunctional (meth) acrylate compound. .
(3) A cured film obtained by curing the curable coating composition according to (1) or (2).
(4) A scratch-resistant resin plate in which a cured film obtained by curing the curable coating composition according to (1) or (2) is formed on the surface of a resin substrate.
(5) The scratch-resistant resin plate according to (4), wherein the resin substrate is made of methacrylic resin.
(6) The scratch-resistant resin plate according to (4) or (5), wherein the pencil hardness is 6H or more.
(7) A display window protection plate for a portable information terminal comprising the scratch-resistant resin plate according to any one of (4) to (6).

  The “portable information terminal” in the present invention means a generic name of a device that has a window (display) for displaying character information, image information, and the like that is large enough to be carried by a person. For example, the mobile phone, PHS, PDA, etc. exemplified above are mentioned.

  According to the present invention, since the curable coating composition contains hafnium, a carboxylic acid having a double bond in the molecule, and a polyfunctional (meth) acrylate compound, a cured film having high hardness (pencil hardness) is formed. There is an effect that can be.

  In particular, as described in (2) above, when the curable coating composition is a mixture of hafnium and a sol composition containing a carboxylic acid having a double bond in the molecule, and a polyfunctional (meth) acrylate compound. A hardened film with higher hardness can be formed.

  According to the scratch-resistant resin plate of (4), since the hardened coating film is formed on the surface of the resin substrate, this scratch-resistant resin plate is used for the portable information terminal as described in (7). By using it as a display window protection plate, the display window can be effectively protected.

  The curable coating composition of the present invention contains hafnium, a carboxylic acid having a double bond in the molecule, and a polyfunctional (meth) acrylate compound. A cured film formed by curing a curable coating composition having such a composition can exhibit high hardness.

  In particular, a cured film having a higher hardness can be formed, and the sol composition containing the hafnium and the carboxylic acid having a double bond in the molecule is mixed with the polyfunctional (meth) acrylate compound. A curable coating composition is preferred.

  As a preferred method for preparing the sol composition, first, in an inert gas atmosphere, hafnium is added to the solvent in the form of hafnium halide, and then water, a carboxylic acid having a double bond in the molecule, and an inorganic acid are sequentially added. Add. A desired sol composition is obtained by stirring the mixed solution under a constant temperature condition. This sol composition has a double bond in the molecule in part or all of hafnium by adding a carboxylic acid having a double bond in the molecule when the hafnium halide is hydrolyzed. It is presumed that the carboxylic acid is in a coordinated form, and thus it is considered that the curable coating composition containing the sol composition can form a cured film having higher hardness.

  Examples of the inert gas include nitrogen, argon, helium and the like, and nitrogen is particularly preferable. Examples of the hafnium halide include, for example, hafnium tetrachloride, hafnium tetrafluoride, hafnium tetrabromide, hafnium tetraiodide, etc., and particularly preferred is hafnium tetrachloride, which is a mixture of one or more kinds. It may be used.

  Examples of the solvent include water, alcohols such as methanol, ethanol, butanol, isopropanol, and vinyl alcohol, ketones such as acetone, methyl ethyl ketone, and dioxane, amines, amides, and the like. Water and alcohols are particularly preferable. Alternatively, two or more kinds may be mixed and used.

  Examples of the carboxylic acid having a double bond in the molecule include unsaturated fatty acids having about 3 to 10 carbon atoms such as acrylic acid, methacrylic acid, crotonic acid, 4-pentenoic acid, and 5-hexenoic acid. Acrylic acid and methacrylic acid are particularly preferred, and these may be used alone or in combination.

  Examples of the inorganic acid include hydrochloric acid, nitric acid, sulfuric acid and the like, and nitric acid and sulfuric acid are particularly preferable. These may be used alone or in combination of two or more.

  The solvent is 10 to 1000 parts by weight, preferably 500 to 600 parts by weight, based on 100 parts by weight of the hafnium halide. The water should be 10 to 100 parts by weight, preferably 50 to 60 parts by weight. The carboxylic acid having a double bond in the molecule is about 10 to 1000 parts by weight, preferably about 200 parts by weight. The inorganic acid is 10 to 100 parts by weight, preferably 30 to 40 parts by weight. As stirring temperature, it is 0-100 degreeC, Preferably it is about 50 degreeC. The stirring time is preferably about 4 hours.

  In the sol composition, the proportion of hafnium is 0.1 to 10 parts by weight with respect to 100 parts by weight of the polyfunctional (meth) acrylate compound contained in the curable coating composition, and the proportion of carboxylic acid having a double bond in the molecule. Is preferably added to the curable coating composition so as to be 1 to 100 parts by weight.

  The polyfunctional (meth) acrylate compound is a curable compound having a property of being cured when irradiated with an activation energy ray such as an electron beam or ultraviolet ray, and has at least two (meth) acryloyloxy in the molecule. It means a compound having a group. In particular, a compound having three or more functional groups, that is, a compound having at least three (meth) acryloyloxy groups in the molecule is preferably used. In the present specification, the (meth) acryloyloxy group means an acryloyloxy group or a methacryloyloxy group. In addition, “(meth)” in the case of (meth) acrylate, (meth) acrylic acid and the like has the same meaning.

  Examples of the polyfunctional (meth) acrylate compound include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and trimethylol. Propane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, pentaglycerol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerin tri (meth) acrylate, dipentaerythritol Tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol Ruhekisa (meth) acrylate, tris [(meth) acryloyloxyethyl] isocyanurate, tripentaerythritol octa (meth) acrylate.

  A phosphazene-based (meth) acrylate compound having a (meth) acryloyloxy group introduced into the phosphazene ring of the phosphazene compound; a polyisocyanate having at least two isocyanate groups in the molecule, and at least one (meth ) Urethane (meth) acrylate compound obtained by reaction with a polyol compound having an acryloyloxy group and a hydroxyl group; a compound having at least two carboxylic acid halide groups in the molecule, and at least one (meth) acryloyl in the molecule Polyester (meth) acrylate compounds obtained by a reaction with a polyol compound having an oxy group and a hydroxyl group; oligomers such as dimers and trimers of each of the above compounds can also be used. These polyfunctional (meth) acrylate compounds are used alone or in admixture of two or more.

  The curable coating composition may contain conductive fine particles as necessary. Thereby, a cured film having antistatic performance and antistatic performance can be formed. Examples of the conductive fine particles include metal oxides such as antimony oxide, indium / tin composite oxide (ITO), tin / antimony composite oxide (ATO), antimony / zinc composite oxide, and phosphorus doping. And fine particles such as tin oxide.

  The conductive fine particles preferably have a particle size of 0.001 to 0.1 μm. When the particle size is too small, industrial production is difficult, and when the particle size is too large, the transparency of the cured film is lowered, which is not preferable.

  It is preferable that the usage-amount of electroconductive fine particles is 1-100 weight part with respect to 100 weight part of curable compounds. If the amount used is too small, a sufficient antistatic effect cannot be obtained, and if it is too large, the scratch resistance of the cured film is lowered or the film formability is lowered.

  Further, the curable coating composition may contain a solvent in order to adjust the viscosity, the thickness of the cured film, and the like. Examples of the solvent include methanol, ethanol, 1-propanol, 2-propanol (isopropyl alcohol), 1-butanol, 2-butanol (sec-butyl alcohol), 2-methyl-1-propanol (isobutyl alcohol), 2- Alcohols such as methyl-2-propanol (tert-butyl alcohol), 2-ethoxyethanol, 2-butoxyethanol, 3-methoxy-1-propanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol Alkoxy alcohols such as ketols such as diacetone alcohol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, aromatic hydrocarbons such as toluene and xylene, and esters such as ethyl acetate and butyl acetate. Le, etc. can be mentioned, which may be used alone or in combination.

  The amount of the solvent used is appropriately adjusted according to the substrate material, shape, coating method, desired thickness of the cured film, etc., but usually the total amount of the curable compound and the conductive fine particles used as necessary. The amount is about 20 to 10,000 parts by weight with respect to 100 parts by weight.

  Furthermore, the curable coating composition may contain additives such as a stabilizer, an antioxidant, a colorant, and a leveling agent as necessary. In particular, when a leveling agent is contained, the smoothness and scratch resistance of the cured film can be improved.

  As the leveling agent, silicone oil is preferable, and examples thereof include dimethyl silicone oil, phenylmethyl silicone oil, alkyl / aralkyl modified silicone oil, fluorosilicone oil, polyether modified silicone oil, fatty acid ester modified silicone oil, methyl hydrogen. Silicone oil, silanol group-containing silicone oil, alkoxy group-containing silicone oil, phenol group-containing silicone oil, methacryl-modified silicone oil, amino-modified silicone oil, carboxylic acid-modified silicone oil, carbinol-modified silicone oil, epoxy-modified silicone oil, mercapto-modified Examples thereof include silicone oil, fluorine-modified silicone oil, and polyether-modified silicone oil. These silicone oils may be used alone or in combination of two or more.

  The usage-amount of a silicone oil is 0.01-20 weight part normally with respect to 100 weight part of total amounts of a sclerosing | hardenable compound and the electroconductive fine particles used as needed. If the amount used is too small, it is difficult to obtain the intended effect, and if it is too large, the strength of the cured film is lowered, which is not preferable.

  Next, the scratch-resistant resin plate of the present invention will be described. The scratch-resistant resin plate of the present invention is formed by forming a cured film obtained by curing the above-described curable coating composition according to the present invention on the surface of a resin substrate.

  Examples of the material constituting the resin substrate include polyethylene, polypropylene, 4-methyl-pentene-1, polystyrene, ABS resin, AS resin, ACS resin, polyvinyl chloride, polyvinylidene chloride, methacrylic resin, polymethyl acrylate, General resins such as polyethylene terephthalate (PET), vinyl acetate resin, triacetyl cellulose (TAC), cellulose resin, engineering plastics such as polyamide resin, polyacetal, polycarbonate, polyphenylene oxide, polysulfone, etc., methacrylic resin, Polycarbonate is preferred, and methacrylic resin is particularly preferred.

  Here, the methacrylic resin is a polymer mainly composed of a methacrylic acid ester, and may be a homopolymer of a methacrylic acid ester, or a methacrylic acid ester of 50% by weight or more and other monomers of 50% by weight. It may be a copolymer with: In the case of a copolymer, the ratio of the methacrylic acid ester in the total monomer is preferably 70% by weight or more, more preferably 90% by weight or more.

  As the methacrylate ester, alkyl methacrylate is preferably used, and methyl methacrylate is particularly preferably used. Examples of monomers other than methacrylic acid esters include acrylic acid esters such as methyl acrylate and ethyl acrylate, aromatic alkenyl compounds such as styrene and methyl styrene, unsaturated carboxylic acids such as acrylic acid and methacrylic acid, Examples include alkenyl cyanide compounds such as acrylonitrile and methacrylonitrile.

  The resin substrate preferably has a total light transmittance of 90% or more when applied to a display window protection plate of a portable information terminal. The total light transmittance is a value measured with a haze meter, as will be described later.

  The resin substrate may have a flat surface like a normal plate (sheet) or film, or a curved surface like a convex lens or a concave lens. Also good. Further, a fine structure such as fine irregularities may be provided on the surface.

  The resin substrate may be colored with a dye or a pigment, if necessary, or may contain an antioxidant, an ultraviolet absorber, rubber particles, or the like.

  The thickness of the resin substrate is preferably 0.1 mm or more, and preferably 3.0 mm or less. When the thickness of the resin substrate is within this range, sufficient rigidity can be exhibited while maintaining transparency.

  After applying the above-described curable coating composition according to the present invention to the surface of such a resin substrate, it is dried as necessary, and then the formed coating film is cured to form the surface of the resin substrate. A cured film having high hardness (pencil hardness) can be formed.

  The curable coating composition can be applied by a method such as a micro gravure coating method, a roll coating method, a dipping coating method, a spin coating method, a die coating method, a cast transfer method, a flow coating method, or a spray coating method.

  The coating film is suitably cured by irradiating with an activation energy ray. Examples of the activation energy rays include electron beams, ultraviolet rays, and visible rays, and are appropriately selected according to the type of curable compound. In the case where ultraviolet rays or visible rays are used as the activation energy rays, a photopolymerization initiator is usually used.

  Examples of the photopolymerization initiator include acetophenone, acetophenone benzyl ketal, anthraquinone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, carbazole, xanthone, 4-chlorobenzophenone, 4, 4'-diaminobenzophenone, 1,1-dimethoxydeoxybenzoin, 3,3'-dimethyl-4-methoxybenzophenone, thioxanthone, 2,2-dimethoxy-2-phenylacetophenone, 1- (4-dodecylphenyl) -2- Hydroxy-2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, triphenylamine, 2,4,6-trimethylbenzoyldiphenylphosphine Oxide, 1-hydro Cycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, fluorenone, fluorene, benzaldehyde, benzoin ethyl ether, benzoisopropyl ether, benzophenone, Michler ketone, 3-methylacetophenone, 3,3 ′, 4,4′-tetra-tert-butylperoxycarbonylbenzophenone (BTTB), 2- (dimethylamino) -1- [4- (morpholinyl) phenyl] -2- (phenylmethyl) -1-butanone, 4-benzoyl -4'-methyldiphenyl sulfide, benzyl and the like.

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

  A commercial item can be used for the photoinitiator illustrated above. Examples of commercially available photopolymerization initiators include “IRGACURE 651”, “IRGACURE 184”, “IRGACURE 500”, “IRGACURE 1000”, “IRGACURE 2959”, sold by Ciba Specialty Chemicals, Inc., respectively. “DAROCUR 1173”, “IRGACURE 907”, “IRGACURE 369”, “IRGACURE 1700”, “IRGACURE 1800”, “IRGACURE 819”, and “IRGACURE 784”, respectively, “KAYACURE” sold by Nippon Kayaku Co., Ltd. "ITX", "KAYACURE DETX-S", "KAYACURE BP-100", "KAYACURE BMS", and "KAYACURE 2-E" AQ "and the like.

  When using a photoinitiator, the usage-amount is 0.1 weight part or more normally with respect to 100 weight part of curable compounds. If the amount used is too small, the curing rate tends not to increase as compared with the case where no photopolymerization initiator is used. In addition, the upper limit of the usage-amount of a photoinitiator is about 10 weight part normally with respect to 100 weight part of curable compounds.

  Moreover, the intensity | strength and irradiation time of an activation energy ray are suitably adjusted according to the kind of curable compound, the thickness of the coating film, etc. The activation energy ray may be irradiated in an atmosphere of an inert gas, and examples of the inert gas include nitrogen and argon.

  The thickness of the formed cured film is preferably 1 to 10 μm, more preferably 2 to 6 μm. If the thickness is too small, the hardness (pencil hardness) may be insufficient, and if it is too large, cracks are likely to occur when exposed to high temperature and high humidity. The thickness of the cured coating can be adjusted by adjusting the amount per area of the curable coating composition applied to the surface of the resin substrate and the solid content concentration contained in the curable coating composition.

  In the scratch-resistant resin plate of the present invention obtained as described above, a cured film having high hardness (pencil hardness) is formed on the surface of the resin substrate. Specifically, the pencil hardness is 6H or more. The pencil hardness is a value measured according to JIS K 5600-5-4. Therefore, the scratch-resistant resin plate of the present invention can be suitably used as a display window protection plate for portable information terminals typified by mobile phones. Further, it can be used as various members in fields requiring high hardness (high pencil hardness) such as a finder portion of a digital camera or a handy type video camera, a display window protection plate of a portable game machine, and the like.

  In order to produce a display window protection plate for a portable information terminal from the scratch-resistant resin plate of the present invention, first, processing such as printing and drilling is performed as necessary, and cutting processing is performed to a required size. Then, if the cut-resistant scratch-resistant resin plate is set on the display window of the portable information terminal, a display window with high hardness (pencil hardness) can be obtained.

  Examples of the present invention will be described below, but the present invention is not limited thereto. In the following examples, “%” and “part” representing the content or amount used are based on weight unless otherwise specified. Moreover, the measuring method of each physical property is as follows.

(Film thickness)
The thickness of the cured film of the obtained scratch-resistant resin plate was measured using a film thickness measuring device [“F-20” manufactured by Filmmetrics Co., Ltd.].

(Total light transmittance)
The total light transmittance of the scratch-resistant resin plate was measured using a haze meter ["HR-100" manufactured by Murakami Color Research Laboratory Co., Ltd.].

(Pencil hardness)
The pencil hardness of the obtained scratch-resistant resin plate was measured according to JIS K 5600-5-4.

  Sol composition A was obtained as follows. That is, first, under a nitrogen atmosphere, 5.44 g of hafnium tetrachloride was added to 31.8 g of ethanol and stirred, and then 3.07 g of water was added and completely dissolved. Next, 11.25 g of acrylic acid and 1.79 g of 60% nitric acid were sequentially added to this solution, and the total amount was adjusted to 60 g with ethanol. This mixed solution was stirred at about 50 ° C. for 4 hours, and ethanol corresponding to the weight loss was added to make 60 g. After cooling to room temperature, insolubles were removed by suction filtration to obtain a colorless and transparent sol composition A [hafnium / acrylic acid].

  Dipentaerythritol hexaacrylate 12.5 parts and pentaerythritol tetraacrylate 12.5 parts as a curable compound, photopolymerization initiator [IRGACURE 184, 3.44 parts of Ciba Specialty Chemicals Co., Ltd., and “IRGACURE 907” 0.31 part], 0.01 part of BYK-307 from BYK Japan as a leveling agent, and 37 parts of isobutyl alcohol and 37 parts of 1-methoxy-2-propanol as a solvent were mixed. To 90 parts of these mixed solutions, 10 parts of the above-mentioned sol composition A was mixed to prepare a curable coating. Incidentally, the ratio of hafnium to 100 parts by weight of the polyfunctional (meth) acrylate compound (curable compound) contained in the curable coating is 2.0 parts, and the ratio of carboxylic acid (acrylic acid) having a double bond in the molecule. Is 7.5 parts.

  This paint was applied to one side of a methacrylic resin plate (Sumitex E, Sumitomo Chemical Co., Ltd.) having a thickness of 3 mm and a size of 50 mm × 50 mm by a bar coat method, followed by drying at room temperature for 1 minute, and further at 60 ° C. for 2 minutes. The coating film was formed on the surface of the methacrylic resin plate by drying for a minute.

Next, the coating film was cured by irradiating with a high-pressure mercury lamp at an illuminance of 80 W / cm ² for 20 seconds, and a scratch-resistant resin plate (a high-strength coating plate having a thickness of 5 μm formed on the surface of the methacrylic resin plate (high A pencil hardness resin plate) was obtained.

  A cured film having a thickness of 5 μm is formed on the surface of the tacryl resin plate by performing the same operation as in Example 1 except that 5.94 parts of “IRGACURE 184” of Ciba Specialty Chemicals Co., Ltd. is used as the photopolymerization initiator. A scratch-resistant resin plate on which was formed was obtained.

[Comparative Example 1]
Except that the sol composition A was not added, the same operation as in Example 1 was performed to obtain a scratch-resistant resin plate in which a cured film having a thickness of 5 μm was formed on the surface of the methacrylic resin plate.

[Comparative Example 2]
Sol composition B was obtained as follows. That is, first, in a nitrogen atmosphere, 5.44 g of hafnium tetrachloride was added to 31.9 g of ethanol and stirred, and then 3.07 g of water was added and completely dissolved. Next, 7.40 g of formic acid, 1.79 g of 60% nitric acid, and 55.3 g of ethanol were sequentially added to this solution, followed by stirring at 50 ° C. for 4 hours. Then, it cooled to room temperature and obtained sol composition B (hafnia sol).

  12.5 parts dipentaerythritol hexaacrylate and 12.5 parts pentaerythritol tetraacrylate as curable compounds, 1.25 parts photopolymerization initiator [IRGACURE 184 from Ciba Specialty Chemicals Co., Ltd.], Big Chemie as leveling agent 0.01 part of “BYK-307” manufactured by Japan Co., Ltd. and 37 parts of isobutyl alcohol and 37 parts of 1-methoxy-2-propanol were mixed as a solvent. The above sol composition B (20 parts) was mixed with 80 parts of these mixed solutions to prepare a curable coating. Incidentally, the ratio of hafnium to 100 parts by weight of the polyfunctional (meth) acrylate compound (curable compound) contained in the curable coating is 0.5 part.

  This paint was applied to one side of a plasma-treated methacrylic resin plate (Sumipex E, Sumitomo Chemical Co., Ltd.) having a thickness of 3 mm and a size of 50 mm × 50 mm, followed by drying at room temperature for 1 minute. Furthermore, it dried at 60 degreeC for 2 minute (s), and formed the coating film on the surface of a methacrylic resin board.

Next, the coating film was cured by irradiating with a high pressure mercury lamp at an illuminance of 80 W / cm ² for 60 seconds to obtain a scratch-resistant resin plate having a cured coating film having a thickness of 3 μm formed on the surface of the methacrylic resin plate. .

In the plasma treatment of the methacrylic resin plate, the plasma irradiation apparatus uses Plasma Treat FG1001 (Nippon Plasma Treat Co., Ltd.), the dry air supply amount is 2 m ³ / h, and the irradiation width is about 20 mm. there were. The voltage during plasma irradiation was 218 to 222 V, and the current was 5.6 to 5.7 V.

  About each scratch-resistant resin board obtained above, pencil hardness was measured in accordance with the measuring method described above. The results are shown in Table 1.

  As is apparent from Table 1, the scratch-resistant resin plate of Comparative Example 1 to which no sol composition A was added, that is, hafnium and carboxylic acid (acrylic acid) having a double bond in the molecule was not contained. The pencil hardness was 4H, and it was not possible to form a cured film with high hardness. The scratch-resistant resin plate of Comparative Example 2 that did not contain a carboxylic acid having a double bond in the molecule (acrylic acid) had a pencil hardness of 5H.

  In contrast, the scratch-resistant resin plates of Examples 1 and 2 have higher pencil hardness than the scratch-resistant resin plates of Comparative Examples 1 and 2, and a cured film having high scratch resistance is formed. .

Claims (7)

  A curable coating composition comprising hafnium, a carboxylic acid having a double bond in the molecule, and a polyfunctional (meth) acrylate compound.   The curable coating composition according to claim 1, wherein the sol composition containing hafnium and a carboxylic acid having a double bond in the molecule is mixed with the polyfunctional (meth) acrylate compound.   A cured film obtained by curing the curable coating composition according to claim 1.   A scratch-resistant resin plate formed by forming a cured film obtained by curing the curable coating composition according to claim 1 on the surface of a resin substrate.   The scratch-resistant resin plate according to claim 4, wherein the resin substrate is made of methacrylic resin.   The scratch-resistant resin plate according to claim 4 or 5, wherein the pencil hardness is 6H or more.   A display window protection plate for a portable information terminal comprising the scratch-resistant resin plate according to any one of claims 4 to 6.