JP4323365B2 - Acrylic resin board manufacturing method - Google Patents

Description

  The present invention relates to a method for producing an acrylic resin plate having excellent heat resistance.

  Acrylic resin plates are used in lenses, automobile parts, lighting parts, various electronic displays and the like because of their excellent optical properties. However, the acrylic resin plate has a drawback that its heat resistance is insufficient when heat treatment is performed at a high temperature.

  As a technique for improving the heat resistance of an acrylic resin plate, there is a method of introducing a crosslinked structure by adding a polyfunctional monomer during polymerization of methyl methacrylate. For example, for the purpose of mainly improving heat resistance and impact resistance, cast polymerization is performed by adding a polyfunctional (meth) acrylate of alkylene glycol to a composition comprising a methyl methacrylate homopolymer and methyl methacrylate. A method has been proposed (see, for example, Patent Document 1). However, this method usually does not provide sufficient heat resistance. In order to obtain sufficient heat resistance by this method, it is necessary to add a large amount of polyfunctional (meth) acrylate, and in that case, the appearance of the resulting resin molded product tends to deteriorate.

  In addition, for the purpose of improving heat resistance and appearance, a method in which at least one of cyclohexadiene and a derivative thereof and a terpenoid compound and a derivative thereof is added to methyl methacrylate and a polyfunctional (meth) acrylate to perform polymerization polymerization. Has been proposed (see, for example, Patent Document 2). However, this method usually does not provide sufficient heat resistance. Moreover, the obtained resin board becomes easy to absorb moisture.

  In addition, for the purpose of improving heat resistance and appearance, a composition comprising an alkyl methacrylate syrup obtained by blending an alkyl methacrylate monomer and a (meth) acrylate crosslinking agent and polymerizing a part thereof, and a crosslinking agent Has been proposed (see, for example, Patent Document 3). However, in this method, gelation tends to occur when a syrup is prepared by blending a crosslinking agent.

  In addition, for the purpose of improving the appearance, a method has been proposed in which the ratio between the crosslinking agent and the alkyl methacrylate polymer is defined in a certain region (see, for example, Patent Document 4). However, here, there is no description of implementation in which the polyfunctional monomer exceeds 20% by mass, and this method usually cannot provide sufficient heat resistance. Furthermore, in order to obtain a resin plate having high heat resistance and excellent appearance, there are restrictions on the composition, which becomes a hindrance to industrialization.

  In addition, a monomer mainly composed of methyl methacrylate and allyl (meth) acrylate are at least two kinds having a difference of 5 ° C. or more between a high and low 10-hour half-life temperature of 75 ° C. A method for producing an acrylic resin plate that undergoes cast polymerization using a radical polymerization initiator has been proposed (see, for example, Patent Document 5). However, in this method, the allyl group has poor polymerizability, and there is a tendency that sufficient heat resistance cannot be obtained.

Furthermore, a method for producing an optical material that undergoes radical polymerization using a polyfunctional (meth) acrylate having an olefinic group as a main component has been proposed (see, for example, Patent Documents 6 and 7). With this method, good heat resistance and low hygroscopicity can be obtained, but there is a problem that the amount of residual monomer in the resulting resin plate is large because the polyfunctional (meth) acrylate having an olefinic group is poorly polymerizable. .
Japanese Patent Publication No. 4-75241 JP 2002-265538 A JP 63-30510 A JP-A-61-225207 Japanese Patent Laid-Open No. 9-25305 Japanese Patent Publication No. 4-30410 JP-A-11-222508

  An object of the present invention is to provide a method for producing an acrylic resin plate having excellent heat resistance and a small amount of residual monomer.

  The present invention relates to 3 to 10% by mass of a monofunctional alkyl acrylate monomer and 2 to 62% by mass of a monoethylenically unsaturated monomer containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms. , 0.01 to 1 part by mass of a polymerization initiator having a 10-hour half-life temperature of 80 ° C or more per 100 parts by mass of a mixture containing 35 to 95% by mass of a polyfunctional (meth) acrylate represented by the following general formula (1) And a mercapto compound in an amount of 0.01 to 0.5 parts by mass to form a polymerizable mixture, and a method for producing an acrylic resin plate having a step of polymerizing and curing the polymerizable mixture.

(Wherein R ¹ represents H or CH ₃ ).

  Furthermore, this invention is a manufacturing method of the acrylic resin laminated body which forms a transparent conductive film on at least one surface of the acrylic resin board obtained by the said manufacturing method.

  In the method for producing an acrylic resin plate of the present invention, since a specific composition is adopted, the heat resistance and the residual monomer amount can be greatly improved while maintaining the excellent optical properties of the acrylic resin. In particular, the acrylic resin plate obtained by this production method is very useful as an acrylic resin laminate in which a transparent conductive film such as an ITO film is formed thereon.

<Acrylic resin plate>
The method for producing an acrylic resin plate of the present invention comprises a monoethylenically unsaturated monomer comprising 3 to 10% by mass of a monofunctional alkyl acrylate monomer and a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms. Start of polymerization with a 10-hour half-life temperature of 80 ° C. or more per 100 parts by mass of a mixture containing 2 to 62% by mass of the monomer and 35 to 95% by mass of the polyfunctional (meth) acrylate represented by the general formula (1) A step of containing 0.01 to 1 part by mass of an agent and 0.01 to 0.5 part by mass of a mercapto compound to form a polymerizable mixture and polymerizing and curing the polymerizable mixture is included.

  Content of a monofunctional alkyl acrylate monomer is 3 to 10% by mass in the mixture. When this content is 3% by mass or more, the amount of residual monomer is reduced, and when it is 10% by mass or less, heat resistance tends to be improved. Furthermore, this content is preferably 5 to 10% by mass.

  The monofunctional alkyl acrylate monomer is preferably an alkyl acrylate having an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl acrylate ester having an alkyl group having 1 to 4 carbon atoms include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, i-butyl acrylate, and acrylic. Examples include t-butyl acid. These can also be used in combination. Of these, methyl acrylate is particularly preferable.

  Examples of monofunctional alkyl acrylate monomers other than alkyl acrylate having an alkyl group having 1 to 4 carbon atoms include, for example, 2-ethylhexyl acrylate, lauryl acrylate, tridecyl acrylate, stearyl acrylate, acrylic acid Examples include isostearyl, cyclohexyl acrylate, benzyl acrylate, isobornyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, methoxyethyl acrylate, and ethoxyethyl acrylate. . These can also be used in combination.

  Content of the monoethylenically unsaturated monomer containing the methacrylic acid alkyl ester which has a C1-C4 alkyl group is 2-62 mass% in a mixture. When the content is 2% by mass or more, the appearance is improved, and when it is 62% by mass or less, the heat resistance tends to be improved. Further, the content is preferably 5 to 50% by mass, and more preferably 10 to 45% by mass. Moreover, when the total amount of the monoethylenically unsaturated monomer containing the methacrylic acid alkyl ester which has a C1-C4 alkyl group is 100 mass parts, the methacrylic acid alkyl ester which has a C1-C4 alkyl group Is preferably 50 parts by mass or more, and the ratio of other monoethylenically unsaturated monomers is preferably 50 parts by mass or less. When the ratio is set, transparency tends to be improved, and heat resistance may be further improved.

  Examples of the alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, and methacrylic acid. Examples include t-butyl acid. These can also be used in combination. Of these, methyl methacrylate is particularly preferred.

  Examples of the monoethylenically unsaturated monomer other than the methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms include those other than the monofunctional alkyl acrylate monomer. For example, styrene, α-methylstyrene, acrylonitrile, methacrylic acid, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, isostearyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, isobornyl methacrylate, methacryl Examples include glycidyl acid, tetrahydrofurfuryl methacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, and the like. These can also be used in combination. Among them, alkyl methacrylate having an alkyl group having 8 to 20 carbon atoms such as 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, and isostearyl methacrylate is preferable from the viewpoint of a decrease in water absorption.

  Content of the polyfunctional (meth) acrylate shown by the said General formula (1) is 35-95 mass% in a mixture. When this content is 35% by mass or more, the heat resistance is improved, and when it is 95% by mass or less, the appearance tends to be good. This content is preferably 45 to 90% by mass, and more preferably 50 to 85% by mass.

The compound represented by the general formula (1), for example, bis (oxymethyl) tricyclo [5,2,1,0 ^2,6] decane acrylate, bis (oxymethyl) tricyclo [5, 2, 1, 0 ^2,6 ] decanedimethacrylate. These can also be used in combination.

  Moreover, other polyfunctional (meth) acrylate can also be used together as needed. Specific examples thereof include ethylene glycol dimethacrylate, ethylene glycol diacrylate, 1,3-propanediol dimethacrylate, 1,3-propanediol diacrylate, 1,4-butylene glycol dimethacrylate, and 1,4-butylene glycol diacrylate. Acrylate, 1,6-hexanediol dimethacrylate, 1,6-hexanediol diacrylate, 2-methyl-1,3-propanediol dimethacrylate, 2-methyl-1,3-propanediol diacrylate, neopentyl glycol diacrylate Methacrylate, neopentyl glycol diacrylate, 2,2′-dimethyl-1,4-butanediol dimethacrylate, 2,2′-dimethyl-1,4-butanediol diacrylate, trimethylolpropane trimethacrylate, Trimethylolpropane triacrylate, pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane hexa methacrylate, ditrimethylolpropane hexaacrylate, dipentaerythritol hexamethacrylate, dipentaerythritol hexaacrylate, and the like. Two or more kinds of the other polyfunctional (meth) acrylates described above may be used in combination as necessary. The amount of the other polyfunctional (meth) acrylate is preferably 15% by mass or less in the mixture, and more preferably 10% by mass or less. If it is 15% by mass or less, the low hygroscopicity tends to be improved, and the appearance may be improved.

  In the present invention, 0.01 to 1 part by weight of a polymerization initiator having a 10-hour half-life temperature of 80 ° C. or more per 100 parts by weight of a mixture containing the above-mentioned monomers as main components, and a mercapto compound 0.01 to 0.5 parts by mass is added to obtain a polymerizable mixture.

  Examples of the polymerization initiator having a 10-hour half-life temperature of 80 ° C. or more include 1,1′-azobis (cyclohexane-1-carbonitrile) (10-hour half-life temperature 88 ° C.), 2,2′-azobis (2 , 4,4-trimethylpentene) (10-hour half-life temperature 110 ° C.), 2-cyano-2-propyrazoformamide (10-hour half-life temperature 104 ° C.), dicumyl peroxide (10-hour half-life temperature 117 ° C.) T-butylcumyl peroxide (10-hour half-life temperature 121 ° C.), di-t-butyl peroxide (10-hour half-life temperature 126 ° C.), t-butyl peroxy-3,3,5-trimethylhexanoate (10-hour half-life temperature 100 ° C.), t-butyl peroxylaurate (10-hour half-life temperature 95 ° C.), t-butyl peroxyacetate (10-hour half-life temperature 03 ° C.), di-t-butylperoxyhexahydroterephthalate (10-hour half-life temperature 83 ° C.), di-t-butyl peroxyazelate (10-hour half-life temperature 99 ° C.), t-butyl peroxyallyl carbonate (10-hour half-life temperature 94 ° C), t-butyl peroxyisopropyl carbonate (10-hour half-life temperature 97 ° C), 1,1-di-t-butylperoxycyclohexane (10-hour half-life temperature 97 ° C), t -Hexylperoxyisopropyl monocarbonate (10 hour half-life temperature 95 ° C), 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane (10 hour half-life temperature 95 ° C), 1,1- And di-t-hexylperoxy-3,3,5-trimethylcyclohexane (10 hour half-life temperature 87 ° C.). These can also be used in combination. The upper limit of the 10-hour half-life temperature is preferably 130 ° C.

  The addition amount of the polymerization initiator having a 10-hour half-life temperature of 80 ° C. or more is 0.01 to 1 part by mass per 100 parts by mass of the mixture. When the addition amount is 0.01 parts by mass or more, the heat resistance is improved and the residual monomer amount tends to decrease. Moreover, there exists a tendency for a residual initiator to reduce that it is 1 mass part or less, and for heat stability to become favorable. Furthermore, this addition amount is preferably 0.02 to 0.5 parts by mass.

  A polymerization initiator having a 10-hour half-life temperature of less than 80 ° C. can be used in combination with such a polymerization initiator. Examples of the polymerization initiator having a 10-hour half-life temperature of less than 80 ° C. include t-butyl peroxyisobutyrate (10-hour half-life temperature 77 ° C.), t-butyl peroxy-2-ethylhexanoate (10 Time half-life temperature 72 ° C), t-butyl peroxypivalate (10-hour half-life temperature 55 ° C), t-hexyl peroxypivalate (10-hour half-life temperature 53 ° C), t-butylperoxyneodecano Ate (10-hour half-life temperature 47 ° C.), 2,2′-azobisisobutyronitrile (10-hour half-life temperature 65 ° C.), 2,2′-azobis (2,4-dimethylvaleronitrile) (10 hours And a 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile) (10 hour half-life temperature 30 ° C.). These can also be used in combination.

  Examples of the mercapto compound include t-butyl mercaptan, n-butyl mercaptan, n-octyl mercaptan, t-dodecyl mercaptan, n-dodecyl mercaptan, and the like.

  The addition amount of a mercapto compound is 0.01-0.5 mass part per 100 mass parts of mixtures. When the added amount is 0.01 parts by mass or more, the amount of residual monomers decreases, and when it is 0.5 parts by mass or less, the heat resistance tends to be improved. Furthermore, this addition amount is preferably 0.03 to 0.3 parts by mass.

  The polymerizable mixture contains the above-described components as main components, but if necessary, a colorant, a release agent, an antioxidant, a stabilizer, an antistatic agent, an antibacterial agent, a flame retardant, and an impact resistance modifier. A quality control agent, a light stabilizer, an ultraviolet absorber, a light diffusing agent, a polymerization inhibitor, a polymerization regulator such as terpinolene, and the like can be added.

  An acrylic resin plate can be obtained by polymerizing and curing the polymerizable mixture described above. Various conventionally known methods can be used as a polymerization and curing method for the polymerizable mixture. Particularly preferred is a so-called casting polymerization method in which a polymerizable mixture is injected into a mold, polymerized and cured, and then peeled off from the mold. Below, the method of casting polymerization which uses methyl acrylate as a monofunctional alkyl acrylate monomer and methyl methacrylate as a methacrylic acid alkyl ester which has a C1-C4 alkyl group is illustrated. However, the present invention is not limited to this.

First, methyl acrylate, methyl methacrylate, bis (oxymethyl) tricyclo [5,2,1,0 ^2,6] Dekanji (meth) acrylate, further copolymerizable other monoethylenically unsaturated optionally The monomer is charged into a suction bottle and stirred to obtain a mixture. A polymerization initiator, a mercapto compound, and a polymerization regulator as necessary are added to the mixture, and vacuum deaeration is performed to obtain a polymerizable mixture. This polymerizable mixture is poured into a mold constituted by sandwiching a gasket between a pair of tempered glass sheets, placed in a heating furnace and polymerized and cured at 40 to 70 ° C. for 2 to 5 hours, and at 100 to 150 ° C. for 1 to 6 hours. And peeling from the mold to obtain an acrylic resin plate.

  Instead of this tempered glass sheet, for example, a mirror surface SUS sheet, a glass sheet with fine irregularities on the surface, an endless belt made of mirror surface SUS that runs oppositely can be used as a mold. Further, the polymerization temperature and time may be appropriately selected as desired.

  The thickness of the acrylic resin plate is preferably 0.5 to 5 mm. When the plate thickness is 0.5 mm or more, when the plate is produced by bulk polymerization, cracks tend not to occur when the acrylic resin plate is peeled from the mold. Moreover, when it is 5 mm or less, there is a tendency that it is difficult to break the plate during polymerization.

  The acrylic resin plate obtained by the present invention is greatly improved in heat resistance and residual monomer amount while maintaining the excellent optical properties of the acrylic resin. Such acrylic resin plates are, for example, peripheral materials for exothermic light sources such as incandescent lamp covers and halogen lamp covers, parts of heating household appliances such as clothes dryers, microwave ovens, ovens, eyeglass lenses, sunglasses lenses, and cameras. In-vehicle materials such as lenses, video camera lenses, goggles lenses, contact lenses and other optical lenses, meter covers and other in-vehicle parts, in-vehicle audio equipment parts, in-vehicle display device parts, in-vehicle navigation system parts, Furthermore, it can be used for various display members such as a front plate of various display devices such as a plasma display device, a liquid crystal display device, and a projection display device, and a light guide plate of a liquid crystal display.

<Transparent conductive film>
The acrylic resin plate obtained in the present invention can be formed into an acrylic resin laminate by forming a transparent conductive film on at least one surface thereof. The transparent conductive film may be a transparent and conductive thin film. For example, an inorganic thin film or an organic polymer thin film can be used.

  Examples of the material for the inorganic thin film include transparent metal oxides such as tin oxide, indium oxide, and ITO (tin-added indium oxide). Of these, ITO is preferable. Examples of the material for the organic polymer thin film include polyisothianaphthene.

  As a method for forming a transparent conductive film on an acrylic resin plate, various conventionally known film forming methods can be used. Examples of film forming methods include vacuum film forming methods such as vacuum deposition, sputtering, CVD, and ion plating.

  Here, a specific example of film formation by sputtering of an ITO thin film will be described. First, in the cleaning step, the transparent substrate is washed with pure water or alkaline water and dried in the atmosphere at a temperature of 120 ° C. or higher, preferably 120 to 150 ° C. for 1 to 4 hours. Then, ITO is sputtered at a temperature of 100 to 150 ° C., preferably 120 to 150 ° C. under vacuum. When used as a transparent electrode plate for a touch panel, the thickness of the transparent conductive film is preferably 10 to 50 nm, and more preferably 25 to 40 nm. If the thickness within these ranges is adopted, it is possible to reduce the weight and thickness as compared with the transparent electrode plate for a touch panel using a glass substrate.

  An acrylic resin laminate in which a transparent conductive film such as ITO is formed on at least one surface on an acrylic resin plate can be used for applications of transparent conductive materials. For example, electrical component circuit materials such as capacitors and resistors, copying materials such as electrophotography and electrostatic recording, transparent electrodes for signal input for liquid crystal displays, electrochromic displays, electroluminescence displays, touch panels, etc. In addition to photoelectric conversion elements such as batteries and optical amplifiers, it can be used for various applications such as antistatic members, electromagnetic wave shielding members, surface heating elements, and sensors. Especially, it is preferable to utilize as a transparent electrode plate for touch panels.

  Hereinafter, the present invention will be described more specifically with reference to examples. In the following description, “part” is based on mass. Each evaluation in the table was performed according to the following method.

(1) Evaluation of acrylic resin plate:
(1-1) Deflection temperature under load:
In order to evaluate the heat resistance of the acrylic resin plate, the deflection temperature under load was measured according to the measurement method shown in JIS-K7207.

(1-2) Haze:
In order to evaluate the optical characteristics of the acrylic resin plate, haze was measured in accordance with the measurement method shown in JIS-K7136.

(1-3) Residual monomer amount:
To evaluate the bis acrylic resin plate in (oxymethyl) tricyclo [5,2,1,0 ^2,6] Dekanji (meth) amount of residual monomer of acrylate, sample 0 was pulverized into pellets with a nipper .1 g was added to 20 ml of methylene chloride, allowed to stand at 23 ° C. for 4 days, the supernatant solution was injected into a gas chromatograph, and the amount of residual monomer was measured. The measurement conditions of the gas chromatograph are shown below.
Apparatus: HP6890 manufactured by Hewlett-Packard Company
Data processor: HP ChemStation Column used: HP-5 0.32 mmφ × 30 m × 0.25 μm film thickness Column temperature conditions: 40 ° C./1 min hold → 290 ° C./3 min hold, 20 ° C./min temperature rise INJ temperature: 280 ° C
Carrier gas (He) flow rate: 20.0 ml / min.

(1-4) Appearance:
In order to evaluate the appearance of the acrylic resin plate, ten samples were prepared, and the number of samples free from defects such as whitening and sink marks was visually indicated as n / 10.

(2) Evaluation of acrylic resin laminate:
(2-1) Total light transmittance:
In order to evaluate the transparency of the acrylic resin laminate, the total light transmittance was measured based on the measurement method described in JIS-K7361.

(2-2) Deformation of substrate:
Whether or not the acrylic resin plate (substrate) is deformed is observed with the naked eye in a series of manufacturing processes of drying the substrate before forming the transparent conductive film (ITO) and then forming the film by sputtering. When there was no deformation in the plate, it was evaluated as “◯” (good), and when the deformation occurred, it was evaluated as “x” (bad).

(2-3) ITO state:
Regarding the state of the transparent conductive film (ITO), observe the film forming process by sputtering method, and if no optical distortion or crack is observed, evaluate it as “Good” (good) and optical distortion or crack Was evaluated as “x” (defect).

(2-4) Surface resistivity:
The surface resistivity of the transparent conductive film was measured by the four probe method.

(2-5) Adhesiveness:
Using a cutter, scratches were made on the transparent conductive film (ITO) in a grid pattern of 11 pieces in the vertical and horizontal directions at intervals of 1 mm so as to reach the resin substrate, and 100 squares of 1 × 1 mm were produced. An adhesive tape (manufactured by Nichiban, product name cellophane tape) was closely adhered on the mesh, and was peeled off in a 45 ° front direction. At this time, the number (n) of the cells remaining without peeling off the transparent conductive film was indicated as n / 100. Specifically, the value of n is preferably 96 or more, and more preferably 100. It can be said that the larger the value of n, the higher the adhesion of the transparent conductive film.

<Manufacture of acrylic resin plate>
[Example 1]
And 7 parts of methyl acrylate, and 10 parts of methyl methacrylate, bis (oxymethyl) tricyclo [5,2,1,0 ^2,6] and decane dimethacrylate 80 parts, mixtures 100 per parts of 3 parts isostearyl methacrylate 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile) (10 hour half-life temperature 30 ° C.) as a polymerization initiator, 0.05 part, t-hexylperoxypivalate (10 hour half-life) (Temperature 53 ° C.) 0.1 part, t-hexylperoxyisopropyl monocarbonate (10 hour half-life temperature 95 ° C.) 0.1 part, mercapto compound t-dodecyl mercaptan 0.05 part, terpinolene 0.03 as a polymerization regulator The parts were mixed, charged into a suction bottle, stirred, and vacuum degassed to obtain a polymerizable mixture.

  This polymerizable mixture was poured into a mold formed by sandwiching a gasket between a pair of tempered glass sheets having a distance of 1.7 mm, removed from the bubbles, placed in a heating furnace, and heated at 55 ° C. for 1 hour and at 50 ° C. for 1 hour. Subsequently, polymerization was carried out at 135 ° C. for 3 hours. Thereafter, the mold was cooled to 40 ° C. or lower and peeled to obtain an acrylic resin plate having a thickness of 1 mm.

  This resin plate had a good appearance without whitening or sink marks. The haze of the resin plate was measured and found to be 0.2%, indicating good transparency. Moreover, the deflection temperature under load exceeded 200 ° C. and was excellent in heat resistance. Furthermore, the residual monomer amount was small (1.31%). Table 1 shows the main raw material composition of the polymerizable mixture of this example, and Table 2 shows the evaluation results.

[Examples 2 to 8, Comparative Examples 1 to 9]
An acrylic resin plate was produced in the same manner as in Example 1 except that the main raw material composition was changed as shown in Tables 1 and 3 (the raw materials not listed in the table are the same as in Example 1). . The evaluation results are shown in Tables 2 and 4.

<Deposition of transparent conductive film>
Each acrylic resin plate obtained in Examples 1 to 8 and Comparative Examples 1 to 9 was washed with pure water, placed in a hot air drying furnace, and dried in air at 150 ° C. for 2 hours. Next, ITO was formed as a transparent conductive film on the resin plate by a sputtering method to obtain an acrylic resin laminate. The film thickness of the transparent conductive film was adjusted to about 30 nm. Moreover, in this sputtering, In ₂ O ₃ / SnO ₂ having a mass ratio of 95/5 is used as a target, exhausted to 10 ⁻³ Pa, argon / oxygen having a volume ratio of 92.5 / 7.5 is used as an introduction gas, RF sputtering was performed under heating at 150 ° C. The evaluation results are shown in Tables 2 and 4.

The abbreviations in each table indicate the following compounds.
· "MA": methyl acrylate, "EA": ethyl acrylate, "ISMA": isostearyl methacrylate "TDMA": bis (oxymethyl) tricyclo [5,2,1,0 ^2,6] Dekanji Methacrylate “HPIC”: t-hexylperoxyisopropyl monocarbonate (10 hours half-life temperature 95 ° C.)
"TDM": t-dodecyl mercaptan "nDM": n-dodecyl mercaptan "C6DA": 1,6-hexanediol diacrylate As shown in Tables 1 and 2, in Examples 1 to 8, acrylic Good results were obtained with respect to heat resistance, transparency, residual monomer amount of the resin plate, transparency, appearance, surface resistivity, and adhesion of the acrylic resin laminate.

  On the other hand, as shown in Tables 3 and 4, in Comparative Examples 1 to 5, there was a problem that the amount of residual monomer in the acrylic resin plate was large, and the surface resistivity and adhesion of the acrylic resin laminate deteriorated. . In Comparative Examples 6 and 7, the appearance of the acrylic resin plate deteriorated. Moreover, in Comparative Examples 8 and 9, the heat resistance of the acrylic resin plate was low, deformation occurred during heating at 150 ° C. during the production of the acrylic resin laminate, and the surface resistivity and adhesion deteriorated.

Claims (4)

Monofunctional acrylic acid alkyl ester monomer 3 to 10% by mass, monoethylenically unsaturated monomer 2 to 62% by mass containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, and the following general formula 0.01 to 1 part by mass of a polymerization initiator having a 10-hour half-life temperature of 80 ° C. or more per 100 parts by mass of the mixture containing 35 to 95% by mass of the polyfunctional (meth) acrylate represented by (1), and a mercapto compound A method for producing an acrylic resin plate comprising a step of containing 0.01 to 0.5 parts by mass to form a polymerizable mixture and polymerizing and curing the polymerizable mixture.

(In the formula, R ¹ represents H or CH _3. )   The method for producing an acrylic resin plate according to claim 1, wherein the monofunctional alkyl acrylate monomer is an alkyl acrylate having an alkyl group having 1 to 4 carbon atoms.   The manufacturing method of the acrylic resin laminated body which forms a transparent conductive film on at least one surface of the acrylic resin board obtained by the manufacturing method of Claim 1 or Claim 2.   4. The method for producing an acrylic resin laminate according to claim 3, wherein the transparent conductive film is an ITO film.