JP2009185230A - Anti-scratch resin plate and display window protection plate in portable information terminal using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anti-scratch resin plate suitable for a display window protection plate in a portable information terminal having a highly scratch resistant cured coating film, and to provide a display window protection plate using the anti-scratch resin plate in the portable information terminal. <P>SOLUTION: The anti-scratch resin plate is formed of a resin substrate and a cured film formed on its surface. The resin substrate is formed of a methacryl resin, while the cured film is formed by curing a curable coating composition comprising a compound having at least three (meth)acryloyloxy groups in the molecule and hafnium. The display window protection plate in the portable information terminal is formed of the anti-scratch resin plate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a scratch-resistant resin plate suitable as a display window protection plate for a portable information terminal, 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 for portable information terminals has a problem that the hardness of the cured coating (pencil hardness) is low and the scratch resistance is not sufficient.

  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 or the like. According to this document, this hard film is described as having a high hardness, and a coating solution containing a predetermined hafnia sol and acrylic acid is applied to the surface of the polycarbonate substrate and cured.

  However, even with such a cured film, sufficient hardness is not obtained at present, and it is suitable as a display window protection plate for a portable information terminal on which a cured film having higher scratch resistance is formed. Development of a scratch-resistant resin plate 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 scratch-resistant resin plate suitable as a display window protective plate for a portable information terminal on which a cured film having high scratch resistance is formed, and a display window protective plate for a portable information terminal using the same. Is to provide.

  As a result of intensive studies, the present inventors have found that a curable coating composition containing, on the surface of a resin substrate made of methacrylic resin, a compound having at least three (meth) acryloyloxy groups in the molecule and hafnium. In the case of forming a cured film by curing, a new fact that a scratch-resistant resin plate suitable as a display window protection plate of a portable information terminal having a highly scratch-resistant cured film formed can be obtained. The present invention has been completed.

That is, the scratch-resistant resin plate of the present invention comprises a resin substrate and a cured coating formed on the surface thereof, the resin substrate comprises a methacrylic resin, and the cured coating comprises at least three molecules in the molecule. It is formed by curing a curable coating composition containing a compound having a (meth) acryloyloxy group and hafnium.
It is preferable that the thickness of the resin substrate is 0.1 to 3 mm.
The hafnium is preferably contained in the curable coating composition as hafnium oxide.

The display window protective plate of the portable information terminal of the present invention is made of the scratch-resistant resin plate.
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.

  Since the scratch-resistant resin plate of the present invention has a highly scratch-resistant cured film formed on the surface of a resin substrate made of methacrylic resin having excellent transparency, the scratch-resistant resin plate is displayed on a portable information terminal. By using it as a window protection plate, the display window can be effectively protected.

  The scratch-resistant resin plate of the present invention comprises a methacrylic resin plate as a substrate and a cured film formed on the surface thereof. The methacrylic resin constituting the substrate is a polymer mainly composed of methacrylic acid ester, and may be a homopolymer of methacrylic acid ester, or 50% by weight or more of methacrylic acid ester and 50% by weight of other monomers. % Or less copolymer. 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 methacrylic resin plate may have a flat surface like a normal plate (sheet) or film, or may have a curved surface like a convex lens or a concave lens. . Further, a fine structure such as fine irregularities may be provided on the surface.

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

  The thickness of the methacrylic resin plate is preferably 0.1 mm or more, more preferably 0.3 mm or more, still more preferably 0.5 mm or more, and preferably 3.0 mm or less. When the thickness of the methacrylic resin plate is within this range, sufficient rigidity can be exhibited while maintaining transparency.

  The cured film is formed by curing a curable coating composition, and the curable coating composition comprises a compound having at least three (meth) acryloyloxy groups in a molecule and hafnium. contains.

  A compound having at least three (meth) acryloyloxy groups in the molecule (polyfunctional (meth) acrylate compound) has a property of curing when irradiated with an activation energy beam such as an electron beam or ultraviolet ray. Compounds such as trimethylolpropane 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 hexa (meth) Acrylate, tris [(meth) acryloyloxyethyl] isocyanurate, tripentaerythritol octa (meth) acrylate and the like, these may be used alone or in combination. 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.

  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 the above compounds can also be used. These may be used alone or in admixture of two or more. In addition, each said compound is prepared so that it may have at least 3 (meth) acryloyloxy groups in a molecule | numerator.

The hafnium is usually contained in the curable coating composition as a hafnium compound, and is preferably contained in the curable coating composition as hafnium oxide. In order to contain hafnium as hafnium oxide in the curable coating composition, hafnium may be added to the curable coating composition in the form of a sol. As a preferred method for preparing the sol, first, hafnium is added to the solvent in the form of a hafnium halide under an inert gas atmosphere, and then water and an inorganic acid are sequentially added. The desired sol can be obtained by stirring the mixed solution under a constant temperature condition. The sol is a hafnium oxide sol (hafnia sol) represented by the general formula: HfO _x (wherein X represents an integer or a decimal number of 2 or less) after hydrolysis of hafnium halide.

  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 inorganic acid include hydrochloric acid, nitric acid, formic acid, sulfuric acid and the like, and formic acid and nitric acid are particularly preferable, and these may be used alone or in combination.

  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 inorganic acid is 10 to 300 parts by weight, preferably 140 to 160 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 hafnia sol, the ratio of hafnium to 100 parts by weight of the compound having at least three (meth) acryloyloxy groups in the molecule contained in the curable coating composition is 0.1 to 100 parts by weight, preferably 3 to 10 parts by weight. It is preferable to add to a curable coating composition so that it may become a weight part.

  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.

  After the curable coating composition described above is applied to the surface of the methacrylic resin plate, it is dried if necessary, and then the formed coating film is cured, so that the surface of the methacrylic resin plate is scratch-resistant. A high cured film 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 this thickness is too small, the scratch resistance may be insufficient. If it is too large, cracks are likely to occur when exposed to high temperatures 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 methacrylic resin plate and the concentration of the solid content contained in the curable coating composition.

  The scratch-resistant resin plate of the present invention has a highly scratch-resistant cured film formed on the surface of a methacrylic resin plate, and is suitably used as a display window protection plate for portable information terminals typified by mobile phones and the like. be able to. Further, it can be used as various members in fields requiring scratch resistance, such as a finder portion of a digital camera or a handheld 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 scratch resistance 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.].

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

  A hafnia sol was obtained as follows. That is, first, under 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 the 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. 20 parts of the above-mentioned hafnia sol was mixed with 80 parts of these mixed solutions to prepare a curable paint. Incidentally, the ratio of hafnium to 100 parts of the compound (curable compound) having at least three (meth) acryloyloxy groups in the molecule contained in the curable coating is 6 parts.

  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.

  A cured film having a thickness of 3 μm was formed on the surface of the methacrylic resin plate by performing the same operation as in Example 1 except that 12.5 parts of dipentaerythritol hexaacrylate and 12.5 parts of pentaerythritol triacrylate were used as the curable compound. A scratch-resistant resin plate on which was formed was obtained.

[Comparative Example 1]
Except for using 25 parts of methyl acrylate as the curable compound, 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 3 μm was formed on the surface of the methacrylic resin plate.

[Comparative Example 2]
Except for using 25 parts of tetraethylene glycol diacrylate as the curable compound, the same operation as in Example 1 was performed to obtain a scratch-resistant resin plate having a 3 μm thick cured film formed on the surface of the methacrylic resin plate. It was.

[Comparative Example 3]
Except that no hafnia sol was 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 3 μm was formed on the surface of the methacrylic resin plate.

[Comparative Example 4]
Except for using a 2 mm thick polycarbonate resin plate as the resin substrate, the same operation as in Example 1 was performed to obtain a scratch-resistant resin plate having a 3 μm thick cured film formed on the surface of the polycarbonate resin plate. .

  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 clear from Table 1, the scratch-resistant resin plates of Examples 1 and 2 have higher pencil hardness than the scratch-resistant resin plates of Comparative Examples 1 to 4, and a cured film having high scratch resistance is formed. I can see that

  On the other hand, the scratch resistant resin plate of Comparative Example 1 using methyl acrylate as the curable compound and the scratch resistant resin plate of Comparative Example 2 using tetraethylene glycol diacrylate both have a pencil hardness of 2H, The cured film showed low scratch resistance.

  Although the composition of the curable compound is the same as in Example 1, the hafnia sol is not added, that is, the scratch-resistant resin plate of Comparative Example 3 that does not contain hafnium has a pencil hardness of 4H, The scratch resistance was lower than that of the scratch-resistant resin plate of Example 1.

  Although the composition of the curable coating is the same as in Example 1, the scratch-resistant resin plate of Comparative Example 4 using a polycarbonate resin plate as the resin substrate has a pencil hardness of B, and the cured film has scratch resistance. The result was lower than that of the scratch-resistant resin plate of Example 1. The following reason is guessed as this reason.

  That is, methacrylic resin is excellent in transparency and has higher rigidity than polycarbonate resin. Moreover, the curable coating containing a compound having at least three (meth) acryloyloxy groups in the molecule has a stronger affinity for the methacrylic resin than for the polycarbonate resin. That is, the scratch-resistant resin plate of Example 1 can form a specific cured film with high adhesion on a highly rigid resin substrate, so that the hardness of the cured film can be sufficiently exhibited. As a result, in the evaluation result of the pencil hardness, the scratch-resistant resin plate of Example 1 showed a higher result than the scratch-resistant resin plate of Comparative Example 4.

Claims (4)

It consists of a resin substrate and a cured film formed on its surface,
The resin substrate is made of methacrylic resin,
The cured film is formed by curing a curable coating composition containing a compound having at least three (meth) acryloyloxy groups in the molecule and hafnium. Board.   The scratch-resistant resin plate according to claim 1, wherein the resin substrate has a thickness of 0.1 to 3 mm.   The scratch-resistant resin plate according to claim 1 or 2, wherein the hafnium is contained in the curable coating composition as hafnium oxide.   A display window protection plate for a portable information terminal comprising the scratch-resistant resin plate according to claim 1.