JP6912212B2 - Ball game machine with excellent visibility - Google Patents

Description

The present invention relates to a ball game machine having excellent visibility.

The ball game machine includes a game board in which a plurality of holes (usually through holes) are formed in the base, and nails for changing the falling direction of the game ball are driven into these holes. In recent years, in order to enhance the entertainment of ball game machines, a translucent resin sheet has been used as a base material, and a display device such as a liquid crystal display device and / or a lighting device such as an LED (light emitting diode) has been combined. It has been proposed (Patent Documents 1, 2, etc.).

Examples of the translucent resin include polycarbonate-based resins and methacrylic-based resins. Since the surface hardness of the polycarbonate resin sheet is relatively low, it tends to be easily scratched by friction with the game ball or collision with the game ball. Since the methacrylic resin sheet has a relatively high surface hardness, it is not easily scratched by friction with the game ball or collision with the game ball. However, general methacrylic resins have insufficient impact resistance, and there is a risk of resin cracking during nailing. Therefore, Patent Document 3 discloses a methacrylic resin sheet having improved impact resistance by adding an acrylic rubber to the methacrylic resin in order to suppress resin cracking during nailing (claim 1). ).

Japanese Unexamined Patent Publication No. 2000-61047 (Patent No. 3765363) Japanese Unexamined Patent Publication No. 7-614 Japanese Unexamined Patent Publication No. 2008-049137 (Patent No. 5317437) Japanese Unexamined Patent Publication No. 2006-305909

As a method for producing a translucent resin sheet, an extrusion molding method in which a molten resin is extruded into a sheet using an extruder equipped with a sheet molding die such as a T die, and this is cooled by using a plurality of cooling rolls. Is preferable. In the extrusion molding method, when the melt viscosity of the resin is particularly high, a plurality of line-shaped defects (so-called die lines) extending in the extrusion molding direction on the translucent resin sheet corresponding to a specific position of a sheet molding die such as a T die. May be formed. It is generally considered that the die line is caused by a defect of the sheet forming die itself such as a T die and the retention of oxidatively deteriorated resin inside the sheet forming die (see paragraph 0008 of Patent Document 4). ..

When a plurality of die lines are formed on the translucent resin sheet, dark lines darker than the other parts may be seen. It is considered that the light condensing portion and the non-light condensing portion are formed by the lens effect of the die line, and the non-light condensing portion relatively dark with respect to the light condensing portion forms a dark line. The die line serves as a light condensing section, and non-light condensing sections are generated on both sides of the light condensing section of one die line, or a non-light condensing section is provided between any two die lines adjacent to each other. It is thought that it will become. On the other hand, in a liquid crystal display device having red, green, and blue dot rows, when a low-luminance emission dot row or a blue dot row having low luminosity factor forms a dark line relatively darker than other color dot rows. There is. When a translucent resin sheet having a plurality of die lines is arranged in front of a liquid crystal display device having a row of red, green, and blue dots, the dark lines formed by the plurality of die lines in the translucent resin sheet and the liquid crystal display device The dark lines formed by the blue dot trains interfere with each other, causing moire in the light emitted from the surface light source on the back surface of the dot trains, which may reduce the visibility of the display.

The present invention has been made in view of the above circumstances, and is a ball game machine provided with a liquid crystal display device and a translucent resin sheet, capable of suppressing the occurrence of moire and the resulting deterioration of display visibility. The purpose is to provide.

The present invention provides the following ball game machines [1] to [6].
[1] A ball game machine including a liquid crystal display device having red, green, and blue dot rows and a translucent resin sheet arranged in front of the liquid crystal display device.
The translucent resin sheet is an extrusion-molded sheet, and the extrusion-molding direction of the sheet is a direction inclined by 50 to 90 ° with respect to a row of blue dots of the liquid crystal display device.
[2] The ball game machine according to [1], wherein the translucent resin sheet contains a methacrylic resin (A) and / or a polycarbonate resin.
[3] The ball game machine of [2], wherein the translucent resin sheet further contains an acrylic rubber (B).
[4] The ball game machine of [3], wherein the acrylic rubber (B) is a multilayer structure particle containing at least one rubber layer.
[5] The ball game machine according to [3] or [4], wherein the content of the acrylic rubber (B) in the translucent resin sheet is 15 to 30% by mass.
[6] The ball gaming machine according to any one of [1] to [5], wherein the translucent resin sheet has a thickness of 5 to 20 mm.

According to the present invention, it is possible to provide a ball game machine provided with a liquid crystal display device and a translucent resin sheet, capable of suppressing the occurrence of moire and the resulting decrease in visibility of the display.

It is a microscope photographed image of the liquid crystal display device (LCD-1) used in the section of [Example].

The ball game machine of the present invention is a translucent resin sheet (hereinafter, simply abbreviated as "resin sheet" or "sheet") arranged at a certain space in front of the liquid crystal display device and the liquid crystal display device. There is) and.
In the present invention, the translucent resin sheet is an extrusion-molded sheet. The translucent resin sheet has a larger area than the liquid crystal display device, and a plurality of holes (usually through holes) are formed in the non-arranged portion of the liquid crystal display device, and these holes are used to change the falling direction of the game ball. The nail is driven. In the present specification, the "sheet" is a plate-like material having no flexibility.
In the present invention, the liquid crystal display device has a color filter having a color pattern of red (R), green (G), and blue (B), and displays a dot displaying red, a dot displaying green, and blue. One pixel is composed of three dots of dots. The liquid crystal display device has a red, green, and blue dot sequence, and in one embodiment, the red, green, and blue array pattern is a striped array (see FIG. 1). As the liquid crystal display device, a known one can be used.
The ball game machine of the present invention may include a lighting device such as an LED (light emitting diode) and other components, if necessary.

Hereinafter, a method for manufacturing a ball game machine will be outlined.
First, a translucent resin sheet is molded by an extrusion molding method. Extrusion molding can be carried out by a known method, in which a molten resin is extruded into a sheet using a single-screw or twin-screw extruder equipped with a sheet molding die such as a T die, and this is cooled by a plurality of sheets. A translucent resin sheet can be molded by an extrusion molding method in which a roll is used for cooling.
Next, for the translucent resin sheet formed by the extrusion molding method, if necessary, a cutting process for cutting the resin sheet into a predetermined shape using a saw or the like, or nailing using a drill or the like. It is possible to perform hole drilling to make holes and holes for mounting various game members, and external shape processing to adjust the shape using a router or the like. The nailing hole is preferably a through hole.
A translucent resin sheet molded and processed as described above, a liquid crystal display device equipped with a light source, a lighting device such as an LED (light emitting diode) if necessary, and other components if necessary. Can be combined to manufacture a ball game machine.

As described in the section [Problems to be Solved by the Invention], in the extrusion molding method, especially when the melt viscosity of the resin is high, the translucent resin corresponds to a specific position of a sheet molding die such as a T die. A plurality of line-shaped defects (so-called die lines) extending in the extrusion molding direction may be formed on the sheet. When a plurality of die lines are formed on the translucent resin sheet, dark lines darker than the other parts may be seen. It is considered that the light condensing portion and the non-light condensing portion are formed by the lens effect of the die line, and the non-light condensing portion relatively dark with respect to the light condensing portion forms a dark line. The die line serves as a light condensing section, and non-light condensing sections are generated on both sides of the light condensing section of one die line, or a non-light condensing section is provided between any two die lines adjacent to each other. It is thought that it will become. On the other hand, in a liquid crystal display device having red, green, and blue dot rows, when a low-luminance emission dot row or a blue dot row having low luminosity factor forms a dark line relatively darker than other color dot rows. There is. When a translucent resin sheet having a plurality of die lines is arranged in front of a liquid crystal display device having a row of red, green, and blue dots, the dark lines formed by the plurality of die lines in the translucent resin sheet and the liquid crystal display device The dark lines formed by the blue dot array may interfere with each other to cause moire, which may reduce the visibility of the display.

In the ball game machine of the present invention, in order to stably suppress the occurrence of moire, the extrusion molding direction of the translucent resin sheet is set to a direction inclined by 50 to 90 ° with respect to the blue dot array of the liquid crystal display device. .. With such a configuration, it is possible to stably suppress the occurrence of moire and the resulting decrease in visibility of the display.

Hereinafter, preferred embodiments of the translucent resin sheet will be described.
The thickness of the translucent resin sheet is preferably 5 to 20 mm, more preferably 5 to 15 mm. If the thickness is less than 5 mm, the sheet tends to warp, especially in a temperature environment of 40 ° C. or higher, which tends to cause nail pulling out or the position of the nail to change. If the thickness exceeds 20 mm, the sheet becomes heavy. Therefore, the handleability tends to decrease.

The translucent resin sheet contains one or more thermoplastic resins, preferably a methacrylic resin (A) and / or a polycarbonate resin, as a main component. Examples of the polycarbonate resin include bisphenol A polycarbonate resin and the like. The methacrylic resin (A) is particularly preferable because it has a relatively high surface hardness and is not easily scratched by friction with the game ball or collision with the game ball. The content of the methacrylic resin (A) is preferably 55 to 85% by mass, more preferably 70 to 85% by mass.
In this specification, the "main component" is defined as a component of 50% by mass or more.

The methacrylic resin (A) can contain a methyl methacrylate (MMA) monomer unit and, if necessary, one or more other monomer units. Other monomeric units include (meth) such as methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. Acrylic acid alkyl ester can be mentioned. The methacrylic resin (A) is preferably a linear polymer. In the methacrylic resin (A), the content of the MMA monomer unit is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, and particularly preferably 90 to 100% by mass.

The methacrylic resin (A) has a weight average molecular weight (Mw) of preferably 50,000 to 300,000, more preferably 52,000 to 250,000, and particularly preferably 55,000 to 20000. When the Mw of the methacrylic resin (A) is within the above range, mechanical properties such as toughness and impact resistance are good, and a sheet having a uniform thickness and excellent surface smoothness can be easily obtained.

From the viewpoint of moldability, the Tg of the methacrylic resin (A) is preferably 100 ° C. or higher. The upper limit of Tg of the methacrylic resin (A) is usually 130 ° C. Tg can be controlled by adjusting the molecular weight and the like. As used herein, "Tg" is the glass transition temperature.

The method for producing the methacrylic resin (A) is not particularly limited, and known polymerization methods such as a radical polymerization method and an anion polymerization method can be applied. From the viewpoint of obtaining a methacrylic resin having high thermodegradability, few foreign substances, and high transparency, solvent-free continuous radical polymerization, anion polymerization, and the like are preferable. In the above-mentioned known polymerization method, the methacrylic resin (A) in which Mw is in a desired range by adjusting the polymerization temperature, the polymerization time, the type or amount of the chain transfer agent, the type or amount of the polymerization initiator, and the like. Can be manufactured.

The translucent resin sheet further comprises an acrylic rubber (B) when the thermoplastic resin contains a methacrylic resin (A) and / or a polycarbonate resin, particularly when the thermoplastic resin contains a methacrylic resin (A). It is preferable to include it. The acrylic rubber (B) can improve the impact resistance of the resin sheet and suppress resin cracking during nailing. The acrylic rubber (B) is not particularly limited, and examples thereof include multilayer structure particles (BX) containing at least one rubber layer, block copolymer (BY), and the like. The acrylic rubber (B) is preferably multilayer structure particles (BX) because the effect of improving impact resistance can be effectively obtained.

The multilayer structure particles (BX) including at least one rubber layer are acrylic rubber particles having a so-called core-shell structure including a soft layer (rubber layer) and a hard layer. If the amount of the multilayer structure particles (BX) added is too small, the effect of improving the impact resistance cannot be effectively obtained, and the resin may crack during nailing. If the amount of the multilayer structure particles (BX) added is excessive, the transparency and surface hardness of the resin sheet may decrease. Since the effect of improving impact resistance is effectively obtained and the transparency and surface hardness of the resin sheet are improved, the content of the multilayer structure particles (BX) in the translucent resin sheet is preferably 15% by mass. As described above, it is more preferably 15 to 45% by mass, further preferably 15 to 30% by mass, particularly preferably 18 to 30% by mass, and most preferably 20 to 30% by mass.

Unless otherwise specified in the present specification, the content of multilayer structure particles (BX) shall be measured as follows. After sufficiently drying a piece of the resin sheet to remove water, its mass (W1) is measured. Next, the sheet piece is placed in a test tube, acetone is added to dissolve the sheet, and the acetone-soluble portion is removed. Then, acetone is removed using a vacuum heater / dryer, and the mass of the residue (W2) is measured. The content of multilayer structure particles (BX) is determined based on the following equation.
[Content of multilayer structure particles (BX)] = (W2 / W1) × 100 (%)

When the outermost layer of the multilayer structure particles (BX) is dissolved in acetone, the blending amount of the multilayer structure particles (BX) may not match the content obtained in the above measurement. However, in the present specification, it is assumed that the acetone-insoluble portion is a rubber component that contributes to impact resistance, and the content of the multilayer structure particles (BX) is determined.

If the particle size of the multilayer structure particles (BX) in the sheet is too small, the effect of improving the impact resistance cannot be obtained, and the resin may crack during nailing. If the particle size of the multilayer structure particles (BX) in the sheet is excessive, the nails that have been driven in tend to come off easily, especially when the amount of the multilayer structure particles (BX) added is large. The particle size of the multilayer structure particles (BX) in the sheet is preferably 0.05 to 0.3 μm because the effect of improving the impact resistance is effectively obtained and the nail pulling out is suppressed.

Unless otherwise specified in the present specification, the average particle size of the multilayer structure particles (BX) in the latex containing the multilayer structure particles (BX) is measured using a light scattering photometer DLS-600 manufactured by Otsuka Electronics Co., Ltd. It shall be. The average particle size of the multilayer structure particles (BX) in the latex shall be determined by measuring by the dynamic light scattering method using a sample collected from the latex after the completion of polymerization and analyzing by the cumulant method.

In the present specification, unless otherwise specified, the average particle size of the multilayer structure particles (BX) in the sheet shall be determined by cross-sectional observation with a transmission electron microscope (TEM). Specifically, a part of the resin sheet is cut out, cut in the thickness direction by a microtome under freezing conditions, the obtained section is dyed with ruthenium acid, and then the cross section of the dyed rubber particles is observed by TEM. .. The average value of 100 particles is defined as the average particle size.

As the multilayer structure particles (BX), the outermost layer is hard containing at least one methacrylic acid ester unit 40 to 100% by mass and, if necessary, another monomer unit 0 to 60% by mass copolymerizable. It is a layer, and at least one inner layer (layer inside the outermost layer) is at least one kind of acrylic acid ester unit 40 to 99.9% by mass, and if necessary, another monomer unit that can be copolymerized 0 to 0. Acrylic multilayer structure particles (BX-1) which are a soft layer (rubber layer) containing 60% by mass and 0.1 to 5% by mass of a polyfunctional monomer unit are preferable. As used herein, the "polyfunctional monomer" is a cross-linking agent (cross-linking monomer) containing two or more polymerizable functional groups.

From the viewpoint of developing heat resistance, the hard layer constituting the outermost layer of the acrylic multilayer structure particles (BX-1) preferably has a Tg of 25 ° C. or higher when the layer is formed alone. Further, at least one inner layer is composed of a soft layer (rubber layer), and from the viewpoint of exhibiting impact resistance, it is preferable that the Tg when the soft layer is formed alone is less than 25 ° C.

The ratio of the outermost layer to the acrylic multilayer structure particles (BX-1) is not particularly limited, but is 10 to 80% by mass in order to ensure good dispersibility during melt-kneading with the methacrylic resin (A). It is preferable that it is within the range of.

The monomer for the hard layer of the acrylic multilayer structure particles (BX-1) preferably contains methyl methacrylate from the viewpoint of transparency. If necessary, one or more copolymerizable unsaturated monomers and / or polyfunctional monomers which are cross-linking agents can be used for the hard layer in accordance with the methacrylic ester. Examples of the copolymerizable unsaturated monomer include acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, -2-ethylhexyl acrylate, cyclohexyl acrylate, and benzyl acrylate. Examples of the polyfunctional monomer include allyl (meth) acrylate, ethylene glycol di (meth) acrylicate, and divinylbenzene.

As the monomer for the soft layer (rubber layer) of the acrylic multilayer structure particles (BX-1), one or more kinds of acrylic acid esters and one kind that can be copolymerized if necessary from the viewpoint of impact resistance. The above other monomers and one or more polyfunctional monomers are used. Examples of the acrylate ester include methyl acrylate, ethyl acrylate, butyl acrylate, -2-ethylhexyl acrylate, cyclohexyl acrylate, and benzyl acrylate. The acrylic acid ester used for the soft layer (rubber layer) preferably contains butyl acrylate and / or -2-ethylhexyl acrylate. Examples of other monomers copolymerizable with the acrylic acid ester include diene compounds such as 1,3-butadiene and isoprene; aromatic vinyl compounds such as styrene, vinyltoluene, and α-methylstyrene. Examples of the polyfunctional monomer include those similar to the above-mentioned hard layer.

The multilayer structure of the acrylic multilayer structure particles (BX-1) is arbitrary as long as the outermost layer is a hard layer and at least one inner layer is a soft layer. The multi-layer structure includes a two-layer structure of soft layer-hard layer, a three-layer structure of hard layer-soft layer-hard layer, and soft layer-hard layer-soft layer-hard layer from the inner layer to the outer layer. The four-layer structure of the above, and the four-layer structure of hard layer-soft layer-soft layer-hard layer and the like can be mentioned.

The acrylic multilayer structure particles (BX-1) can be produced by a known emulsion polymerization method. First, one or more raw material monomers are emulsion-polymerized to form core particles, and then one or more other monomers are emulsion-polymerized in the presence of the core particles to form a shell around the core particles. Let me. Then, if necessary, one or more types of monomers are further emulsion-polymerized in the presence of particles consisting of a core and a shell to form another shell. By repeating such a polymerization reaction, the target acrylic multilayer structure particles (BX-1) can be produced as an emulsified latex.

A known surfactant can be used for emulsion polymerization. The surfactant can be appropriately selected from the viewpoint of the stability of the polymerization system and the particle size of the produced acrylic multilayer structure particles, and an anionic surfactant is preferable. Examples of the anionic surfactant include carboxylic acid salts such as sodium stearate, sodium myristate, and sodium N-lauroyl sarcosinate.

The polymerization initiator used for emulsion polymerization is not particularly limited, and examples thereof include inorganic peroxides such as potassium persulfate and ammonium persulfate. A chain transfer agent can be used for emulsion polymerization, if necessary. Examples of the chain transfer agent include alkyl mercaptans such as n-dodecyl mercaptan, n-lauryl mercaptan, tert-dodecyl mercaptan, and sec-butyl mercaptan.

The acrylic multilayer structure particles (BX-1) are produced by emulsion polymerization, and can be recovered as a powdery polymer by coagulation, dehydration, drying and the like by a known method.

The block copolymer (BY) is not particularly limited, and the methacrylic acid ester polymer block (b1) containing a methacrylic acid ester such as methyl methacrylate as a main component and acrylic containing an acrylic acid ester such as butyl acrylate as a main component. A block copolymer (BY-1) containing an acid ester polymer block (b2) is preferable. The number of methacrylic acid ester polymer blocks (b1) in the block copolymer (BY) is not particularly limited, and may be singular or plural. Similarly, the number of acrylic acid ester polymer blocks (b2) in the block copolymer (BY) is not particularly limited, and may be singular or plural.

From the viewpoint of melt moldability, the thermoplastic resin used for extrusion molding has a melt flow rate (MFR) of preferably 0, which is measured under the condition of 230 ° C. and a 3.8 kg load in accordance with JIS K 7210. .1 g / 10 minutes or more, more preferably 0.1 to 30 g / 10 minutes, particularly preferably 0.5 to 20 g / 10 minutes, most preferably 1.0 to 10 g / 10 minutes.

The translucent resin sheet may contain any component other than the above, if necessary.
The translucent resin sheet can contain one or more other resins. Examples of other resins include silicone-based rubbers; styrene-based thermoplastic elastomers such as SEPS, SEBS, and SIS; and olefin-based rubbers such as IR, EPR, and EPDM. The amount of other resin that can be contained in the translucent resin sheet is preferably 10% by mass or less, more preferably 5% by mass or less, and most preferably 0% by mass.

The translucent resin sheet can contain one or more kinds of various additives. Additives include lubricants, UV absorbers, fillers, antioxidants, heat deterioration inhibitors, light stabilizers, mold release agents, polymer processing aids, antistatic agents, flame retardants, dye pigments, light diffusers, Examples include organic dyes, matting agents, phosphors and the like. The total amount of the additives that can be contained in the translucent resin sheet is preferably 7% by mass or less, more preferably 5% by mass or less, and particularly preferably 4% by mass or less.

Lubricating agent is a component that imparts lubricity to the resin sheet during melt extrusion or processing and lowers the friction coefficient of the resin sheet. By adding this component, in processing such as cutting or drilling of the resin sheet. By the lubrication effect, the frictional heat between the resin sheet and the tool can be suppressed, and the deterioration of the appearance quality of the processed surface of the resin sheet and the fusion of the resin to the tool can be suppressed. Examples of the lubricant include hydrocarbons, fatty acids, fatty alcohols, fatty acid esters, fatty acid amides, metal soaps and the like.

As the fatty acid used as a lubricant, fatty acids having 12 or more carbon atoms such as lauric acid, palmitic acid, stearic acid, behenic acid, oleic acid, and erucic acid are preferable. Among the above, fatty acids having 16 to 24 carbon atoms such as palmitic acid, stearic acid, behenic acid, oleic acid, and erucic acid are more preferable, and saturated fatty acids having 16 to 24 carbon atoms such as palmitic acid, stearic acid, and behenic acid. Fatty acids are particularly preferred. As the aliphatic alcohol used as a lubricant, saturated aliphatic alcohols having 12 to 18 carbon atoms such as lauryl alcohol, palmityl alcohol and stearyl alcohol are more preferable, and palmityl alcohol and stearyl alcohol have 16 to 18 carbon atoms. Saturated fatty alcohols are particularly preferred.

As the fatty acid ester used as a lubricant, an ester (including a partial ester) of the above fatty acid and a monovalent or polyvalent (divalent or higher) alcohol containing the above fatty alcohol is preferable, and the fatty acid having 16 to 22 carbon atoms is used. Fatty acid monoglyceride, which is a partial ester with glycerin, is more preferred.

Examples of the fatty acid amide used as a lubricant include amides and bisamides of the above fatty acids. Examples of such fatty acid amides include lauric acid amides, palmitic acid amides, stearic acid amides, bechenic acid amides, hydroxylstearic acid amides, oleic acid amides, erucic acid amides, N-oleyl palmitate amides, N-stearyl stealic acid amides, and N. Examples thereof include −stearyl oleic acid amide, N-oleyl stearate amide, N-stearyl erucate amide, methylol stearate amide, methylene bisstearic acid amide, methylene biscapric acid amide, and ethylene bislauric acid amide.

An ultraviolet absorber is a compound having an ability to absorb ultraviolet rays. The ultraviolet absorber is a compound that is said to have a function of mainly converting light energy into heat energy. Examples of the ultraviolet absorber include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic acid anilides, malonic acid esters, formamidines and the like. Among them, benzotriazoles, triazines, and _{ultraviolet absorbers having a maximum molar extinction coefficient ε max} of 1200 dm ³ · mol ^-1 cm ^-1 or less at a wavelength of 380 to 450 nm are preferable.

Benzotriazoles are highly effective in suppressing deterioration of optical properties such as coloring due to exposure to ultraviolet rays. Examples of benzotriazoles include 2- (2H-benzotriazole-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (manufactured by BASF; trade name: TINUVIN329), 2- (2H-). Benzotriazole-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol (manufactured by BASF; trade name TINUVIN234) and 2,2'-methylenebis [6- (2H-benzotriazole) -2-yl) -4-tert-octylphenol] (manufactured by ADEKA; LA-31) and the like are preferable.

An ultraviolet absorber having a maximum molar extinction coefficient ε _max of 1200 dm ³ · mol ^-1 cm ^-1 or less at a wavelength of 380 to 450 nm can suppress the yellowness of the obtained molded product. Examples of such an ultraviolet absorber include 2-ethyl-2'-ethoxy-oxalanilide (manufactured by Clariant Japan Co., Ltd .; trade name: Sandeuboa VSU).

Among the above-mentioned ultraviolet absorbers, benzotriazoles and the like are preferably used from the viewpoint of suppressing resin deterioration due to ultraviolet exposure.

Further, when it is desired to efficiently absorb a wavelength in the vicinity of 380 nm, a triazine-type ultraviolet absorber is preferably used. Examples of such an ultraviolet absorber include 2,4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine (manufactured by ADEKA; LA-F70). Examples thereof include hydroxyphenyltriazine-based ultraviolet absorbers (manufactured by BASF; TINUVIN477-D and TINUVIN460).

The antioxidant is effective in preventing oxidative deterioration of the resin by itself in the presence of oxygen. For example, phosphorus-based antioxidants, hindered phenol-based antioxidants, thioether-based antioxidants, and the like can be mentioned. Among them, phosphorus-based antioxidants and hindered phenol-based antioxidants are preferable from the viewpoint of the effect of preventing deterioration of optical properties due to coloring, and the combined use of phosphorus-based antioxidants and hindered phenol-based antioxidants is more preferable. ..

Phosphorus antioxidants include 2,2-methylenebis (4,6-di-t-butylphenyl) octylphosphite (manufactured by ADEKA; trade name: ADEKA STAB HP-10), tris (2,4-dit). -Butylphenyl) phosphite (manufactured by BASF; trade name: IRGAFOS168) and 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa 3 , 9-Diphosphaspiro [5.5] undecane (manufactured by ADEKA; trade name: ADEKA STAB PEP-36) and the like are preferable.

Examples of the hindered phenolic antioxidant include pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (manufactured by BASF; trade name IRGANO01010) and octadecyl-3. -(3,5-di-t-butyl-4-hydroxyphenyl) propionate (manufactured by BASF; trade name IRGANO01076) and the like are preferable.

The heat deterioration inhibitor can prevent the heat deterioration of the resin by capturing the polymer radicals generated when exposed to high heat under a substantially oxygen-free state. Examples of the heat deterioration inhibitor include 2-t-butyl-6- (3'-t-butyl-5'-methyl-hydroxybenzyl) -4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd .; trade name: Sumilyzer GM), and 2,4-di-t-amyl-6- (3', 5'-di-t-amyl-2'-hydroxy-α-methylbenzyl) phenylacrylate (manufactured by Sumitomo Chemical Co., Ltd .; trade name Sumilyzer GS), etc. preferable.

As the polymer processing aid, polymer particles having a particle size of 0.05 to 0.5 μm, which are usually produced by an emulsion polymerization method, are used. Such polymer particles may be single-layer particles composed of polymers having a single composition and a single extreme viscosity, or may be multilayer particles composed of two or more kinds of polymers having different compositions or extreme viscosities. .. In particular, particles having a two-layer structure having a polymer layer having a relatively low ultimate viscosity in the inner layer and a polymer layer having a relatively high ultimate viscosity of 5 dl / g or more in the outer layer are preferable. The average degree of polymerization of the polymer processing aid is preferably 3,000 to 40,000.

As described above, according to the present invention, there is provided a ball game machine provided with a liquid crystal display device and a translucent resin sheet, capable of suppressing the occurrence of moire and the resulting decrease in visibility of the display. be able to.

Examples and comparative examples according to the present invention will be described.
[Manufacturing Example 1]
(Manufacturing of acrylic three-layer structure particles)
In a reactor with a reflux cooler, 145 parts by mass of ion-exchanged water, 0.45 parts by mass of sodium stearate (SS), 0.08 parts by mass of sodium lauryl sarcosinate (LSS), and 0.05 parts by mass of sodium carbonate (SC). After adding parts by mass and stirring and dissolving, 32.9 parts by mass of methyl methacrylate (MMA), 2.1 parts by mass of methyl acrylate (MA), and 0.07 allyl methacrylate (ALMA) as a cross-linking agent. The temperature was raised to 80 ° C. while adding a mass portion and stirring. Next, 1.8 parts by mass of a 2% potassium persulfate aqueous solution was added, the temperature was raised to 80 ° C., and the mixture was held for 60 minutes to obtain latex.
In the presence of the above latex, 2.2 parts by mass of a 2% aqueous potassium persulfate solution was added, 36.99 parts by mass of butyl acrylate (BA), 8.01 parts by mass of styrene (ST), and methacrylic acid as a cross-linking agent. A monomeric mixture consisting of 0.9 parts by mass of allyl acid (ALMA) was continuously added over 60 minutes and retained for 30 minutes after the addition was completed.
Next, 1.0 part by mass of a 2% aqueous potassium persulfate solution was added in the presence of the above latex, and 18.8 parts by mass of methyl methacrylate (MMA), 1.2 parts by mass of methyl acrylate (MA), and n-octyl mercaptan were added. A monomer mixture consisting of 0.04 parts by mass of (n-OM) was continuously added over 30 minutes, and held for 60 minutes after the addition was completed.
As described above, from the center side, the acrylic is composed of a hard layer (first layer), a soft layer (second layer, rubber layer), and a hard layer (third layer), and has an average particle size of 0.23 μm. A latex containing 40% by mass of system three-layer structure particles (BX-1a) was obtained.

(Preparation of methacrylic resin composition and methacrylic resin)
Obtained by emulsion polymerization of 90 parts by mass of MMA and 10 parts by mass of MA for dispersion of acrylic three-layer structure particles (BX-1a), the average particle size is 0.13 μm, and the degree of polymerization is 960. The latex of the first methacrylic resin (A-1) was prepared.
A latex obtained by mixing a latex of acrylic three-layer structure particles (BX-1a) and a latex of a first methacrylic resin (A-1) at a mass ratio of 67:33 is coagulated, filtered, and washed by a known method. It was dehydrated and dried to obtain a first methacrylic resin composition (C-1). The MFR (melt flow rate) of the first methacrylic resin composition (C-1) (impact resistant methacrylic resin composition) was 1.5 g / 10 minutes.

Separately, a powdery second methacrylic resin obtained by suspend polymerization of 94 parts by mass of MMA and 6 parts by mass of MA, having an average particle size of 0.13 μm and a degree of polymerization of 1550. A-2) ("Parapet (registered trademark) EH" manufactured by Kuraray Co., Ltd. was prepared. The MFR of this second methacrylic resin (A-2) was 1.3 g / 10 minutes.

(Manufacturing of acrylic resin sheet)
43 parts by mass of the first methacrylic resin composition (C-1) and 57 parts by mass of the second methacrylic resin (A-2) are made uniform in a tumbler (mixer). Mixed in. The obtained resin mixture is used as a single-screw extruder with a T-die (manufactured by Hitachi Zosen Corporation, screw diameter: 50 mmφ, L / D = 32 (where L is the effective length of the screw and D is the screw diameter. The molten resin mixture was extruded into a sheet from the T-die and cooled using a plurality of cooling rolls to obtain an acrylic resin sheet (S-1) having a width of 350 mm and a thickness of 10 mm. ..

[Example 1]
As a liquid crystal display device, a transmissive TFT liquid crystal display device (LCD-1) having red, green, and blue dot sequences (display area: length 228 mm x width 304 mm, resolution: 1024 (RGB) x 768 (XGA), Hitachi A company-made "TX38D03VM1AAA") was prepared. The liquid crystal display device (LCD-1) is oriented so that the extrusion molding direction of the acrylic resin sheet (S-1) is inclined by 90 ° with respect to the blue dot array of the liquid crystal display device (LCD-1) (orthogonal direction). ), An acrylic resin sheet (S-1) was placed. Table 1 shows the angles of the acrylic resin sheet in the extrusion molding direction with respect to the blue dot array of the liquid crystal display device.

[Example 2, Comparative Examples 1 and 2]
In Example 2 and Comparative Examples 1 and 2, the liquid crystal in the same manner as in Example 1 except that the angle of the extrusion molding direction of the acrylic resin sheet with respect to the blue dot row of the liquid crystal display device was changed as shown in Table 1. An acrylic resin sheet (S-1) was placed on the front surface of the display device (LCD-1).

[Evaluation items and evaluation methods]
The evaluation items and evaluation methods are as follows.
(Pitch of die line of acrylic resin sheet)
The pitch of the die line of the acrylic resin sheet was measured in a dark room by the following method.
A xenon lamp ("xenon short arc lamp" manufactured by Ushio, Inc.) is prepared as a light source, and an acrylic resin sheet (S-1) and a screen are vertically arranged on the light path of the emitted light to form an acrylic resin. The light transmitted through the sheet (S-1) was projected onto the screen. As the screen, a white resin screen having a smooth surface and an overall uniform surface was used. The presence or absence of die lines was visually confirmed based on whether or not shades appeared in the projected image projected on the screen, and if shades appeared, the die line pitch was calculated from the number of die lines within a 1 cm width. A total of 3 evaluation areas of 1 cm x 1 cm were randomly defined (the 3 evaluation areas are R1 to R3, respectively), and measurements were performed on any 3 points in each evaluation area R1 to R3, and the average value was obtained. Asked.

(Pitch of blue dot row of liquid crystal display device)
Using a portable microscope (“Digital Field Microscope DG-2A” manufactured by SCARA Co., Ltd.), observe the liquid crystal display device (LCD-1) with all pixels lit, and observe the pitch of the blue dot sequence (=). The pitch of the dark lines formed by the blue dot sequence) was determined. The obtained photographed image is shown in FIG. The pitch of the blue dot row was 0.32 mm.

(Presence or absence of moire)
With all the pixels of the liquid crystal display device (LCD-1) lit, visually observe the laminated structure of the acrylic resin sheet (S-1) / liquid crystal display device (LCD-1) and evaluate the presence or absence of moire. did. The evaluation criteria are as follows.
○ (Good): No moire was seen.
△ (Yes): Some moire was seen.
× (impossible): Moire was clearly seen.

[Evaluation results]
The evaluation results are shown in Table 1.
As shown in Table 1, in Comparative Examples 1 and 2 in which the extrusion molding direction of the acrylic resin sheet was set to an angle direction of 0 to 40 ° with respect to the blue dot row of the liquid crystal display device, moire was observed. On the other hand, in Examples 1 and 2 in which the extrusion molding direction of the acrylic resin sheet was set to an angle direction of 50 to 90 ° with respect to the blue dot row of the liquid crystal display device, the occurrence of moire could be effectively suppressed.

The present invention is not limited to the above-described embodiments and examples, and the design can be appropriately changed as long as the gist of the present invention is not deviated.

Claims (6)

A ball game machine including a liquid crystal display device having red, green, and blue dot rows and a translucent resin sheet arranged in front of the liquid crystal display device.
The translucent resin sheet is an extrusion-molded sheet, and the extrusion-molding direction of the sheet is a direction of 90 ° with respect to a row of blue dots of the liquid crystal display device. The ball game machine according to claim 1, wherein the translucent resin sheet contains a methacrylic resin (A) and / or a polycarbonate resin. The ball game machine according to claim 2, wherein the translucent resin sheet further contains an acrylic rubber (B). The ball game machine according to claim 3, wherein the acrylic rubber (B) is a multilayer structure particle including at least one rubber layer. The ball game machine according to claim 3 or 4, wherein the content of the acrylic rubber (B) in the translucent resin sheet is 15 to 30% by mass. The ball gaming machine according to any one of claims 1 to 5, wherein the translucent resin sheet has a thickness of 5 to 20 mm.

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