JP2003311891A - Scratch-resistant resin plate and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scratch-resistant resin plate or a scratch-resistant antistatic film having a cured film having good adhesion to a methyl methacrylate-styrene copolymer resin substrate and having sufficient surface hardness. Provide a board. SOLUTION: A compound having alicyclic ring and (meth) acryloyloxy group in a molecule is provided on a surface of a methyl methacrylate-styrene copolymer resin as a substrate.
Parts by weight, and a resin composition containing 20 to 95 parts by weight of a curable compound having at least three (meth) acryloyloxy groups in the molecule or an oligomer thereof is applied and cured to obtain a scratch-resistant resin plate. I do. At this time, if the conductive inorganic particles having an average particle diameter of 0.1 μm or less are dispersed in the resin composition, antistatic properties can be imparted to the obtained cured film. The scratch-resistant resin plate is useful as a front plate for a display, particularly a screen for a projection television.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low moisture absorption and scratch resistant resin plate made of a methylmethacrylate-styrene copolymer resin substrate having a cured film formed on the surface thereof, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, for example, as a front plate for a display including a front plate for a projection television,
Transparent resin plates have been widely used. Since the resin surface is easily scratched, an ultraviolet-curable or thermosetting compound such as an acrylate-based compound, an epoxy-based compound, or an organic silicon compound has been used as a scratch-resistant coating for surface protection. (See, for example, Patent Document 1). It is also known to disperse conductive inorganic particles in a scratch-resistant film to impart antistatic properties in order to prevent adhesion of dust and the like (see, for example, Patent Documents 2 and 3).

On the other hand, a polymethylmethacrylate plate (methacrylic resin plate) or the like is used as a base material for such a front plate for a display, but the polymethylmethacrylate board has a large expansion and contraction due to moisture absorption and warps the base material due to moisture absorption. May occur and the image may be distorted or may come into contact with a part inside the front plate. Compared to polymethylmethacrylate, methylmethacrylate-styrene copolymer resin
It is known to have low hygroscopicity, and there is an attempt to use such a methyl methacrylate-styrene copolymer resin as a front plate of a display (see, for example, Patent Document 4).

[0004]

[Patent Document 1] Japanese Unexamined Patent Publication No. 9-48950

[Patent Document 2] Japanese Patent Laid-Open No. 11-343430

[Patent Document 3] Japanese Patent Laid-Open No. 2001-328220

[Patent Document 4] JP-A-11-7251

[0005]

However, the adhesiveness of conventionally used curable coating materials such as acrylates varies depending on the resin used as the base material, and in particular, the methyl methacrylate-styrene copolymer resin is used as the base material. When a plate is used, its adhesion is greatly reduced. On the other hand, the curable coating that provides good adhesion to the methylmethacrylate-styrene copolymer resin plate should have a cured film with a low hardness and a sufficient cured film as a front plate for a display that requires scratch resistance. I couldn't.

Therefore, the present inventors have found that the scratch-resistant resin plate has a good adhesion to a methylmethacrylate-styrene copolymer resin substrate having a low hygroscopicity and further has a cured film having a sufficient surface hardness formed thereon. Alternatively, as a result of earnest research to develop a scratch-resistant antistatic plate, it was found that sufficient adhesion to a methylmethacrylate-styrene copolymer resin plate was obtained by using a specific curable compound in the coating material for curing. It was found that a cured film having properties and high surface hardness can be obtained, and the present invention has been completed.

[0007]

That is, according to the present invention, a substrate made of a methylmethacrylate-styrene copolymer resin and a cured film formed on the surface of the substrate are formed. 5 to 80 parts by weight of a compound having a cyclic ring and a (meth) acryloyloxy group, and a curable compound having at least 3 (meth) acryloyloxy groups in the molecule or an oligomer thereof 20 to 95
There is provided a scratch-resistant resin plate obtained by curing a resin composition containing parts by weight. It is also possible to disperse conductive inorganic particles having an average particle diameter of 0.1 μm or less in this cured film to impart antistatic property.

This scratch-resistant resin plate is useful as a front plate for a display, especially as a screen for a projection television. Therefore, according to the present invention, there is provided a front plate for a display comprising the above-mentioned scratch-resistant resin plate, and a screen for a projection television comprising the above-mentioned scratch-resistant resin plate.

Further, according to the present invention, 5 to 80 parts by weight of a compound having an alicyclic ring and a (meth) acryloyloxy group in the molecule on the surface of a substrate made of a methylmethacrylate-styrene copolymer resin, and the molecule A resin composition containing 20 to 95 parts by weight of a curable compound having at least 3 (meth) acryloyloxy groups or an oligomer thereof is applied to form a curable film, and then the curable film is cured. This also provides a method for producing a scratch-resistant resin plate. At this time, if the resin composition contains conductive inorganic particles having an average particle diameter of 0.1 μm or less, the resulting cured film can have antistatic properties.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. In the present invention, a methyl methacrylate-styrene copolymer resin is used as the resin substrate. In this copolymer, the amount of styrene can be generally about 10 to 90% by weight, preferably 20% by weight or more, more preferably 30% by weight or more, and preferably 60% by weight or less, It is preferably 50% by weight or less. When the amount of styrene in this copolymer is less than 10% by weight, the hygroscopicity becomes large, and when the amount exceeds 90% by weight, the mechanical properties of the resin substrate deteriorate. This copolymer may contain an impact resistant component. It is also possible to use a crosslinked methyl methacrylate-styrene copolymer resin.

The resin substrate may have a flat surface such as a plate (sheet) or a film, or may have a surface having a curvature such as a convex lens or a concave lens. . In addition, fine irregularities may be provided on the surface. The thickness of the resin substrate greatly varies depending on the use of this scratch-resistant resin plate, but generally 0.5 to 1
A substrate having an appropriate thickness may be selected from the range of about 0 mm depending on the application. From the standpoint of the self-supporting property of the scratch-resistant resin plate finally obtained, it is preferable to use a resin substrate having a thickness of 1.5 mm or more.

Such a methyl methacrylate-styrene copolymer resin is used as a substrate, and a cured film is formed on the surface thereof. In the present invention, as a resin composition (paint) for forming a cured film, an alicyclic ring (meta) is included in the molecule.
A curable compound having an acryloyloxy group (hereinafter sometimes referred to as alicyclic (meth) acryloyloxy compound), and a curable compound having at least three (meth) acryloyloxy groups in the molecule or an oligomer thereof (hereinafter , A polyfunctional (meth) acryloyloxy compound may be used). The (meth) acryloyloxy group means an acryloyloxy group or a methacryloyloxy group, and other (meth) acrylate,
“(Meth)” when referring to (meth) acrylic acid and the like has the same meaning.

The composition of this paint is such that the total resin solid content is 1
As 00 parts by weight, the alicyclic (meth) acryloyloxy compound is 5 to 80 parts by weight, and the polyfunctional (meth) acryloyloxy compound is 20 to 95 parts by weight. The alicyclic (meth) acryloyloxy compound is preferably used in an amount of 10 parts by weight or more, and the polyfunctional (meth) acryloyloxy compound is preferably used in an amount of 90 parts by weight or less. When the amount of the alicyclic (meth) acryloyloxy compound is too small, the adhesion to the methyl methacrylate-styrene copolymer resin substrate may be insufficient, and when the amount is too large, the cured film The surface hardness may decrease. On the other hand, if the amount of the polyfunctional (meth) acryloyloxy compound is too small, the surface hardness of the cured film may decrease.

The alicyclic (meth) acryloyloxy compound, which is one component of the coating material, is a compound having an alicyclic ring and a (meth) acryloyloxy group in the molecule, as described above. The alicyclic ring here may be a carbon monocycle such as a cyclohexane ring, or a carbon polycycle such as a bicyclo [2.2.1] heptane ring (also known as a norbornane ring) or a tricyclodecane ring. Alternatively, it may be a heterocycle such as a tetrahydrofuran ring. Examples of such alicyclic (meth) acryloyloxy compounds include dimethylol-tricyclodecanedi (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, and 2- (meth).
Examples thereof include acryloyloxyethyl hexahydrophthalic acid, isobornyl (meth) acrylate, pentaerythritol tri (meth) acrylate isophorone diisocyanate urethane prepolymer and the like. Although all of these compounds are monomers, they may be used as they are or in the form of oligomers such as dimers and trimers.

Since some of these alicyclic (meth) acryloyloxy compounds are commercially available, such commercially available products can also be used. Examples of commercially available products include "New Frontier IBA" [Daiichi Kogyo Seiyaku Co., Ltd., isobornyl acrylate], "Aronix M-1".
56 "[Toagosei Co., Ltd., isobornyl acrylate]," Light acrylate HOA-HH "[Kyoeisha Chemical Co., Ltd., 2-acryloyloxyethyl hexahydrophthalic acid]," Light acrylate DCP-A "[Kyoeisha Chemical Co., Ltd. , Dimethylol-tricyclodecane diacrylate], "light acrylate THF-A" [Kyoeisha Chemical Co., Ltd., tetrahydrofurfuryl acrylate], "light acrylate UA-3061" [Kyoeisha Chemical Co., Ltd., pentaerythritol triacrylate isophorone diisocyanate urethane pre Polymer] and the like.

The polyfunctional (meth) acryloyloxy compound, which is another component of the paint, is as described above.
At least 3 (meth) acryloyloxy groups in the molecule
It is a compound or an oligomer thereof. In this compound, the number of (meth) acryloyloxy groups in the molecule must be at least 3, but, for example, 4, 5, 6
A larger number such as 7, 7, or 8 may be used. Examples of such a polyfunctional (meth) acryloyloxy compound include:
Trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, glycerin tri (meth) acrylate, pentaglycerol tri (meth) acrylate, pentaerythritol tri-
Or polyvalent such as tetra- (meth) acrylate, dipentaerythritol tri-, tetra-, penta- or hexa- (meth) acrylate, tripentaerythritol tetra-, penta-, hexa- or hepta- (meth) acrylate Poly (meth) acrylate of alcohol; a compound having at least two isocyanate groups in the molecule is reacted with a (meth) acrylate monomer having a hydroxyl group at a ratio such that the hydroxyl groups are equal to or more than the moles of the isocyanate group. Examples of the urethane (meth) acrylate obtained include three or more (meth) acryloyloxy groups in one molecule; tri (meth) acrylate of tris (2-hydroxyethyl) isocyanuric acid. Monomers are exemplified here, but these monomers may be used as they are, for example, those in the form of oligomers such as dimers and trimers may be polyfunctional (meth) acryloyloxy compounds. You may use as.

Since some of these polyfunctional (meth) acryloyloxy compounds are commercially available, such commercially available products can also be used. As a commercially available product, for example, "NK Hard M101" [Shin Nakamura Chemical Co., Ltd.,
Urethane acrylate type], “NK ester A-TMM-3
L ”[Shin Nakamura Chemical Co., Ltd., pentaerythritol triacrylate],“ NK Ester A-TMMT ”[Shin Nakamura Chemical Co., Ltd., pentaerythritol tetraacrylate],“ NK Ester A-9530 ”[Shin Nakamura Chemical Co., Ltd. Company, dipentaerythritol hexaacrylate], “KAYARADDPCA” [Nippon Kayaku Co., Ltd., dipentaerythritol hexaacrylate] and the like.

The alicyclic (meth) acryloyloxy compound and polyfunctional (meth) acryloyloxy compound described above are cured, for example, by irradiating them with an energy ray such as electron beam, radiation or ultraviolet ray, or by heating. It can be done.

The resin composition (paint) containing an alicyclic (meth) acryloyloxy compound and a polyfunctional (meth) acryloyloxy compound has an average particle size of 0.1.
Conductivity can be imparted by dispersing conductive inorganic particles having a size of μm or less. Examples of the conductive inorganic particles used here include antimony-doped tin oxide, phosphorus-doped tin oxide, antimony oxide, zinc antimonate, titanium oxide, and tin-doped indium oxide (I
(TO: indium tin oxide).

When the conductive inorganic particles are used, the average particle size thereof is required to be 0.1 μm or less, and usually 0.001 μm or more. When the average particle diameter of the conductive inorganic particles exceeds 0.1 μm, the haze of the obtained scratch-resistant resin plate tends to increase, and the transparency tends to decrease. When the conductive inorganic particles are used, the amount thereof is 100 parts by weight based on 100 parts by weight of the alicyclic (meth) acryloyloxy compound and the polyfunctional (meth) acryloyloxy compound.
Usually, about 2 to 25 parts by weight is suitable, and preferably 1
It is 5 parts by weight or less, more preferably 10 parts by weight or less.
When the amount of the conductive inorganic particles is less than 2 parts by weight based on 100 parts by weight of the total of the alicyclic (meth) acryloyloxy compound and the polyfunctional (meth) acryloyloxy compound, the conductivity of the cured film obtained is not always required. It may not be enough. If the amount exceeds 25 parts by weight, the total light transmittance may decrease and haze may increase.

Such conductive inorganic particles can be obtained by, for example, vapor phase decomposition method, plasma evaporation method, alkoxide decomposition method, coprecipitation method,
It can be manufactured by a hydrothermal method or the like. The surface of the conductive inorganic particles may be surface-treated with, for example, a nonionic surfactant, a cationic surfactant, an anionic surfactant, a silicon coupling agent, an aluminum coupling agent, or the like. .

In order to produce a coating from the above alicyclic (meth) acryloyloxy compound and polyfunctional (meth) acryloyloxy compound or by dispersing conductive inorganic particles therein, these components are mixed. do it. When mixing, it is preferable to use a solvent. When using a conductive inorganic particles, and when using a solvent, for example, after mixing the conductive inorganic particles and the solvent to disperse the conductive inorganic particles in the solvent, alicyclic (meth) acryloyloxy compound and You may mix with a polyfunctional (meth) acryloyloxy compound, or after mixing an alicyclic (meth) acryloyloxy compound and a polyfunctional (meth) acryloyloxy compound with a solvent, add conductive inorganic particles there. You may mix.

The solvent may be any solvent which can dissolve the alicyclic (meth) acryloyloxy compound and the polyfunctional (meth) acryloyloxy compound and can be volatilized after coating, and a conductive inorganic material as a coating component. When the particles are used, any particles can be used as long as they can be dispersed. For example, diacetone alcohol, methanol, ethanol, isopropyl alcohol, 1-methoxy-2-
Examples include alcohols such as propanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, aromatic hydrocarbons such as xylene, esters such as ethyl acetate, water, and the like. The above mixed solvent may be used.

The resin composition (paint) containing an alicyclic (meth) acryloyloxy compound and a polyfunctional (meth) acryloyloxy compound, and optionally conductive fine particles, further contains another resin component. You may have.

Other resin components that may be optionally contained include
For example, malonic acid / trimethylolethane / (meth) acrylic acid, malonic acid / trimethylolpropane / (meth) acrylic acid, malonic acid / glycerin / (meth) acrylic acid, malonic acid / pentaerythritol / (meth) acrylic acid , Succinic acid / trimethylolethane / (meth)
Acrylic acid, succinic acid / trimethylolpropane / (meth) acrylic acid, succinic acid / glycerin / (meth) acrylic acid, succinic acid / pentaerythritol / (meth) acrylic acid, glutaric acid / trimethylolethane / (meth) acrylic Acid, glutaric acid / trimethylolpropane / (meth) acrylic acid, glutaric acid / glycerin / (meth) acrylic acid, glutaric acid / pentaerythritol /
(Meth) acrylic acid, adipic acid / trimethylolethane / (meth) acrylic acid, adipic acid / trimethylolpropane / (meth) acrylic acid, adipic acid / pentaerythritol / (meth) acrylic acid, adipic acid / glycerin / ( (Meth) acrylic acid, sebacic acid / trimethylolmethane / (meth) acrylic acid, sebacic acid / trimethylolpropane / (meth) acrylic acid, sebacic acid /
Glycerin / (meth) acrylic acid, sebacic acid / pentaerythritol / (meth) acrylic acid, fumaric acid / trimethylolethane / (meth) acrylic acid, fumaric acid / trimethylolpropane / (meth) acrylic acid, fumaric acid / glycerin / (Meth) acrylic acid, fumaric acid / pentaerythritol / (meth) acrylic acid, itaconic acid / trimethylolethane / (meth) acrylic acid, itaconic acid / trimethylolpropane / (meth) acrylic acid, itaconic acid / pentaerythritol / (Meth) acrylic acid,
Mixed polyester of saturated or unsaturated dibasic acid and (meth) acrylic acid by combination of compounds such as maleic anhydride / trimethylolethane / (meth) acrylic acid, maleic anhydride / glycerin / (meth) acrylic acid Is mentioned.

When blending such other resin components,
The amount is usually up to about 30% by weight of the total resin solid content. Such other resin component may be dissolved in a solvent together with the alicyclic (meth) acryloyloxy compound and the polyfunctional (meth) acryloyloxy compound, or when using the conductive inorganic particles, it may be added together with it. Alternatively, the alicyclic (meth) acryloyloxy compound, the polyfunctional (meth) acryloyloxy compound and the conductive inorganic particles may be mixed before or after the mixing.

Further, in order to coat and cure a coating material containing an alicyclic (meth) acryloyloxy compound and a polyfunctional (meth) acryloyloxy compound on a resin substrate, usually, the polymerization is initiated in this coating material. The agent is blended. The polymerization initiator may be one normally used for curing an acrylic curable compound. Further, a leveling agent and other various additives may be included, if necessary.

The coating material thus obtained is applied to the surface of a methyl methacrylate-styrene copolymer resin substrate and then cured to obtain a scratch-resistant resin plate. In order to apply the above-mentioned coating material onto the substrate, a usual method such as a bar coater method or a roll coater method can be adopted.
Thus, the curable film is formed on the surface of the resin substrate.
After that, by irradiating with energy rays or heating, the curable coating on the substrate surface is cured into a cured coating,
A scratch-resistant resin plate is obtained. This cured film is alicyclic (meth) acryloyloxy compound and polyfunctional (meth)
The acryloyloxy compound is cured, or the conductive inorganic particles are dispersed therein.

When the resin is cured by irradiation with energy rays, examples of the energy rays used include ultraviolet rays, electron beams, and radiation. The intensity and irradiation time of the energy rays used include the alicyclic (meth) acryloyloxy compound and It is appropriately selected depending on the type and composition of the polyfunctional (meth) acryloyloxy compound. In the case of curing by heating, the heating temperature and the heating time are appropriately selected depending on the type and composition of the alicyclic (meth) acryloyloxy compound and polyfunctional (meth) acryloyloxy compound used. When the coating material used for coating contains a solvent, the solvent may be volatilized and then the coating may be cured after coating, or the solvent may be volatilized and the coating may be cured simultaneously.

The thickness of the cured film thus obtained is 0.
It is preferably about 5 to 50 μm, more preferably 1 μm
More preferably, it is more than about 20 μm, and more preferably about 20 μm or less. The thickness of the cured film is 50 μm
If it exceeds the range, cracks are likely to occur, and if the thickness is less than 0.5 μm, the scratch resistance tends to be insufficient. Various functional layers such as a low reflection layer and an antifouling layer may be further provided on the cured film.

Since the scratch-resistant resin plate of the present invention has a low hygroscopicity, the amount of warp of the plate is small even after long-term use, and the surface hardness of the cured film is sufficient. Therefore, for example, a cathode ray tube (CRT), a liquid crystal display device (LCD), a plasma display panel (PDP),
It is useful as a front plate for a display that transmits light from a display screen in various displays such as an electroluminescence display (ELD) and a light emitting diode display.

Also, like a projection television,
When used as a front plate for a projection type display that projects an image on the surface of the front plate, the amount of moisture absorbed from the surface is less than when a methacrylic resin plate is used,
Since the warp of the plate is small, the image is well reflected and an image without distortion can be obtained. Therefore, the scratch-resistant resin plate of the present invention is also useful as a screen for a projection display.

In particular, a large front panel for a display having a diagonal size of 40 inches or more and a screen for a projection display have a large size, so that they are likely to expand and contract due to moisture absorption, which causes a problem of warpage. It is desirable that the scratch-resistant resin plate provided for such an application has a water absorption rate of 1% or less when immersed in warm water of 60 ° C. for 24 hours, which makes it difficult to absorb water even after long-term exposure to warm water. . Incidentally, this water absorption rate, by dividing the mass increase due to immersion by the mass before immersion,
Desired.

[0034]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 Dipentaerythritol hexaacrylate [“NK Ester A-9530” obtained from Shin Nakamura Chemical Co., Ltd.] 1
2.5 parts by weight, 12.5 parts by weight of dimethylol-tricyclodecane diacrylate [“light acrylate DCP-A” obtained from Kyoeisha Chemical Co., Ltd.] and 1-methoxy-2.
A coating material was prepared by adding 1.25 parts by weight of 1-hydroxycyclohexyl phenyl ketone [“Irgacure 184”, a polymerization initiator obtained from Ciba Specialty Chemicals Co., Ltd.] to 75 parts by weight of propanol. This coating was applied to one side of a methyl methacrylate-styrene copolymer resin plate [a copolymer of methyl methacrylate and styrene having a weight ratio of 60/40 was formed into a plate having a thickness of 3 mm by an extrusion molding machine] on one side. Apply by
A curable film was formed by drying, and the resin was irradiated with ultraviolet rays to be cured to obtain a resin plate with a cured film. The thickness of the cured film was about 4 μm. This resin plate was evaluated by the following methods, and the results are shown in Table 1.

(1) Total Light Transmittance According to Tt ASTM D 1003, the total transmitted light quantity with respect to the incident light quantity of visible light was measured. (2) Haze Measured according to ASTM D 1003. (3) Steel wool hardness Steel wool No. 0000 10 at a load of 500 g / cm ²
The state of occurrence of scratches on the cured film after reciprocating was visually confirmed. (4) Adhesion of cured film After immersing the sample plate in warm water at 80 ° C for 1 hour and cooling it to room temperature, 100 cross-cuts of the cross-cut film provided on the cured film are peeled by the cross-cut tape method according to JIS K 5400. The presence or absence was observed.

Examples 2 to 3 A cured film having a thickness of about 4 μm was prepared in the same manner as in Example 1 except that the following components were used in place of dipentaerythritol hexaacrylate [“NK ester A-9530”]. A resin plate on which was formed was obtained. The two kinds of compounds used here are the same, but the manufacturers are different, so each was tested. The resin plate thus obtained was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Example 2: Pentaerythritol tetraacrylate (“NK obtained from Shin-Nakamura Chemical Co., Ltd.”
Ester A-TMMT "]. Example 3: Pentaerythritol tetraacrylate [" KAYARAD PET30 "obtained from Nippon Kayaku Co., Ltd.].

Example 4 Urethane acrylate-based curable compound [“NK Hard M101” available from Shin-Nakamura Chemical Co., Ltd. Mixture of compounds having 3 to 6 acryloyloxy groups in one molecule, solid content 80] 15.6 parts by weight (solid content: 12.
5 parts by weight), and 12.5 parts by weight of dimethylol-tricyclodecane diacrylate [“light acrylate DCP-A” obtained from Kyoeisha Chemical Co., Ltd.].
-Methoxy-2-propanol 71.9 parts by weight was added to make a total of 100 parts by weight, and 1-hydroxycyclohexyl phenyl ketone [Irgacure 18 obtained from Ciba Specialty Chemicals Co., Ltd.
4 ", polymerization initiator] 1.25 parts by weight were added and mixed to prepare a paint. Using this paint, the same procedure as in Example 1 was carried out to obtain a resin plate having a cured film of about 4 μm thick formed thereon. This resin plate was evaluated in the same manner as in Example 1 and the results are shown in Table 1.

Example 5 Dipentaerythritol Hexaacrylate [“NK Ester A-9530” Obtained from Shin-Nakamura Chemical Co., Ltd.] 1
2.5 parts by weight, 12.5 parts by weight of dimethylol-tricyclodecane diacrylate [“light acrylate DCP-A” obtained from Kyoeisha Chemical Co., Ltd.] and 1-methoxy-2.
-To 75 parts by weight of propanol, 1.25 parts by weight of 1-hydroxycyclohexyl phenyl ketone [“Irgacure 184”, a polymerization initiator obtained from Ciba Specialty Chemicals Co., Ltd.] was added, and a diantimony pentoxide dispersion liquid was added. “ELCOM PC-1” obtained from Catalyst Kasei Co., Ltd.
4 ", a concentration of 20% by weight, and an average particle size of dispersed diantimony pentoxide of 20 to 30 nm] was added in an amount of 10 parts by weight to prepare a scratch-resistant paint. In the same manner, a resin plate having a cured film with a thickness of about 4 μm was prepared, which was evaluated in the same manner as in Example 1 and the results are shown in Table 1. Also, the results were obtained here. The surface resistance value of the cured film was measured according to JIS K 6911 for the cured resin plate with a cured film of 5.9.
It was × 10 ¹⁰ Ω / □.

Comparative Example 1 Urethane acrylate curable compound [“NK Hard M101” available from Shin-Nakamura Chemical Co., Ltd., mixture of compounds having 3 to 6 acryloyloxy groups in one molecule, solid content 80] % By weight] 31.3 parts by weight (solids content 25 parts by weight) and 68.7 parts by weight of 1-methoxy-2-propanol 1-hydroxycyclohexyl phenyl ketone [Irgacure obtained from Ciba Specialty Chemicals Co., Ltd. 184 ", polymerization initiator] 1.25 parts by weight were added and mixed to prepare a paint. Using this coating material, the same operation as in Example 1 was carried out to produce a resin plate having a cured film with a thickness of about 4 μm formed thereon. About this resin plate, Example 1
Evaluation was carried out in the same manner as in, and the results are shown in Table 1.

Comparative Example 2 Without using dipentaerythritol hexaacrylate ["NK ester A-9530"], dimethylol-
A resin plate on which a cured film having a thickness of about 4 μm was formed in the same manner as in Example 1 except that the coating material was prepared by using 25 parts by weight of tricyclodecane diacrylate [“light acrylate DCP-A”]. Was produced. This resin plate was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0043]

[Table 1]

Example 6 A resin plate with a cured film was produced in the same manner as in Example 1 except that the thickness of the methyl methacrylate-styrene copolymer resin plate was changed to 2 mm. This resin plate, 8
It was vacuum dried at 0 ° C. for 4 hours. Then add 24 ° C water to 23 ° C.
After soaking for 24 hours and after being soaked in warm water at 60 ° C. for 24 hours, the water absorption rate [= {(mass after immersion−mass before immersion) / mass before immersion} × 100%] is measured to obtain hygroscopicity. Was evaluated. As a result, the water absorption rate after being immersed in water at 23 ° C for 24 hours was 0.39%, and the water absorption rate after being immersed in warm water at 60 ° C for 24 hours was 0.83%.

Comparative Example 3 A methacrylic resin plate having a thickness of 2 mm (“SUMIPEX E” obtained from Sumitomo Chemical Co., Ltd.) was used in place of the methyl methacrylate-styrene copolymer resin plate having a thickness of 3 mm. A resin plate with a cured film was produced in the same manner as in Example 1. When this resin plate was evaluated for hygroscopicity in the same manner as in Example 6, the water absorption rate when it was immersed in water at 23 ° C. for 24 hours was 0.44%, and when it was immersed in warm water at 60 ° C. for 24 hours. The water absorption was 1.30%.

[0046]

EFFECTS OF THE INVENTION According to the present invention, a specific combination of a substrate resin and a cured coating provided on the surface thereof has a cured coating excellent in adhesion and surface hardness, and also has a small hygroscopicity and scratch resistance. A resin plate is obtained. In producing the scratch-resistant resin plate, specific conductive inorganic particles are dispersed in the resin composition for forming a cured film, and the conductive inorganic particles are dispersed in the resulting cured film. A scratch-resistant resin plate that also has antistatic properties can be obtained. This resin plate is particularly useful as a front plate for various displays such as a screen for a projection television.

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Claims (7)

[Claims] 1. A substrate comprising a methylmethacrylate-styrene copolymer resin and a cured film formed on the surface of the substrate, wherein the cured film contains an alicyclic ring and (meta) in the molecule.
5 to 80 parts by weight of a compound having an acryloyloxy group,
And a curable compound having at least 3 (meth) acryloyloxy groups in the molecule or an oligomer thereof 20 to
A scratch-resistant resin plate, which is obtained by curing a resin composition containing 95 parts by weight. 2. The scratch-resistant resin plate according to claim 1, wherein conductive inorganic particles having an average particle diameter of 0.1 μm or less are dispersed in the cured film. 3. The scratch-resistant resin plate according to claim 1, which has a water absorption rate of 1% or less when immersed in warm water of 60 ° C. for 24 hours. 4. A front plate for a display, comprising the scratch-resistant resin plate according to claim 1. 5. A screen for a projection television, comprising the scratch-resistant resin plate according to claim 1. 6. A surface of a substrate made of a methyl methacrylate-styrene copolymer resin, 5 to 80 parts by weight of a compound having an alicyclic ring and a (meth) acryloyloxy group in the molecule, and at least 3 in the molecule. Curable compound having (meth) acryloyloxy group or its oligomer 2
A method for producing a scratch-resistant resin plate, which comprises applying a resin composition containing 0 to 95 parts by weight to form a curable film, and then curing the curable film. 7. The resin composition further has an average particle diameter of 0.1 μm.
The method according to claim 6, comprising the following conductive inorganic particles.