JP2006306951A - Method for producing acrylic resin plate, polymerizable composition for touch panel, transparent base plate using the polymerizable composition, transparent electrode plate and touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an acrylic resin plate having good prevention for cracking of the plate in a peeling process during production and excellent in heat resistance, a polymerizable composition suitable for a transparent base plate for touch panels having good prevention for cracking of the plate and excellent in heat resistance and transparency, the transparent base plate for touch panels using the composition, a transparent electrode plate having the base plate and a touch panel having the transparent electrode plates. <P>SOLUTION: The polymerizable composition for touch panels comprises 100 pts.mass mixture consisting of 15-55 mass% monoethylenic unsaturated monomer containing an alkyl methacrylate having a 1-4C alkyl group or a syrup comprising the monomer and a (co)polymer of the monomer and 45-85 mass% polyfunctional (meth)acrylate having 2 or more (meth)acryloyl groups, 0.015-0.2 pts.mass at least one species of compounds selected from a group consisting of cyclohexadiene, its derivatives, terpenoid-based compounds and their derivatives and 0.001-0.1 pt.mass ethyl acid phosphate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing an acrylic resin plate having excellent heat resistance, a polymerizable composition suitable for a transparent substrate for a touch panel, a transparent substrate for a touch panel using the composition, a transparent electrode plate having the substrate, and this The present invention relates to a touch panel having a transparent electrode plate.

<Acrylic resin plate>
Acrylic resin plates are used for lenses, automotive parts, lighting parts, various electronic displays, etc., due to their excellent optical properties, but they have the disadvantage of insufficient heat resistance when heat treatment is performed at high temperatures. There is.

  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 this case, there is a problem that the appearance of the obtained resin molded product is deteriorated.

  In addition, for the purpose of improving heat resistance and appearance, a method in which at least one of cyclopentadiene 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. That is, when at least one of cyclopentadiene and derivatives thereof and terpenoid compounds and derivatives thereof is added, the heat resistance is lowered, and there is a problem of cracking if not peeled at a high temperature in the peeling process during production.

  In addition, for the purpose of improving heat resistance and appearance, a composition comprising an alkyl methacrylate syrup obtained by partially polymerizing an alkyl methacrylate monomer and a (meth) acrylate crosslinking agent and a crosslinking agent is cast. A polymerization method has been proposed (see, for example, Patent Document 3). However, this method has a problem that 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. Moreover, in order to obtain a resin plate having high heat resistance and excellent appearance, there are restrictions on the composition, which hinders industrialization.

  Furthermore, the 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, this method has a problem that the polymerizability of the allyl group is poor and sufficient heat resistance cannot be obtained.

  In addition, for the purpose of improving heat resistance and improving plate cracking prevention in the peeling process during production, a monoethylenically unsaturated monomer containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms; The polyfunctional (meth) acrylate is cast and polymerized by containing a polymerization initiator having a 10-hour half-life temperature of 80 ° C. or more and at least one selected from the group consisting of cyclopentadiene and derivatives thereof, and terpenoid compounds and derivatives thereof. A method has been proposed (see, for example, Patent Document 6). However, according to this method, with the repeated production of the resin plate, the mold surface is gradually contaminated by additives and resin pieces remaining on the mold surface at the time of peeling, and the plate cracking prevention property may deteriorate. Patent Document 6 discloses the use of a mold release agent, but does not mention a specific mold release agent, and further does not mention the amount used.

<Transparent electrode plate for touch panel and touch panel>
A display device-integrated input device in which a transparent touch panel is arranged on a display device such as a liquid crystal display or a cathode ray tube touches the display screen with an input pen or a finger, so that the touch panel acts as an input device to facilitate an input operation. Therefore, it is used as an operation screen of an automatic teller machine such as a portable information terminal or a bank. In particular, a resistive film type analog touch panel is most widely used because it can be applied to any operation screen.

  A resistance film type analog touch panel generally includes an upper transparent electrode plate and a lower transparent electrode plate, and the upper and lower transparent electrode plates have a transparent substrate and a transparent conductive film formed on the transparent substrate. It is an electrode plate, and the upper and lower transparent electrode plates have a configuration in which the transparent conductive films are arranged so as to face each other.

  When the upper transparent electrode plate of the touch panel having such a configuration is pressed with an input pen or a finger, the upper transparent electrode plate is bent and the transparent conductive films of the upper and lower transparent electrode plates are in contact with each other at the pressing point. And the coordinate of this contact point is detected by the measurement of electrical resistance, and input information is read.

  As a transparent electrode plate of such a touch panel, a resin plate is generally used as an upper transparent electrode plate, and a glass plate or a resin plate is used as a transparent substrate for a lower transparent electrode plate, and vacuum deposition is performed on the surface of these transparent substrates. A method in which a transparent conductive film is formed by a vacuum film forming method such as a sputtering method, a CVD (chemical vapor deposition) method, or an ion plating method is used.

  However, the lower electrode plate using a glass plate as a transparent substrate is prone to cracking when assembling and transporting the touch panel, or pressing with a pen or hand, making it difficult to reduce the thickness, making it difficult to reduce the weight, etc. There's a problem.

  On the other hand, when a resin plate is used as a transparent substrate, the problems of substrate breakage, thickness reduction, and weight reduction that occur when a glass plate is used as a transparent substrate can be easily solved. Actually, various studies have been made on upper and lower electrode plates using a resin plate as a transparent substrate (see, for example, Patent Documents 7, 8, and 9). However, the transparent substrate using a resin plate such as polyethylene terephthalate resin disclosed in Patent Documents 7, 8, and 9 has insufficient transparency. In addition, since the heat resistance is insufficient, the transparent substrate surface is easily deformed easily when a transparent conductive film is formed on the transparent substrate. The adhesion of the transparent conductive film is low and the durability is insufficient. There is a problem that further processing is required.

  Further, a methacrylic resin molding material obtained by polymerizing methyl methacrylate and neopentyl glycol dimethacrylate, which is a polyfunctional (meth) acrylate, as monomers is disclosed (for example, see Patent Document 10). However, here, it is not disclosed at all that this methacrylic resin molding material can be used as a transparent substrate of a transparent electrode plate for a touch panel, and it is not suggested at all what composition is suitable as a transparent electrode plate for a touch panel. . Furthermore, since the methacrylic resin molding material described in Patent Document 10 has a low polymerization rate of 4 to 62% by mass, the polymerization rate is further increased by a process such as compression molding or extrusion molding when the molding material is used as a product. It needs to be high. For this reason, distortion occurs and it is not suitable for use on a touch panel.

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 JP 2004-161825 A JP 2000-276301 A JP 2001-14951 A JP 2001-34418 A Japanese Patent Publication No. 5-6570

  The objective of this invention is providing the manufacturing method of the acrylic resin board which was excellent in the board crack prevention property in the peeling process at the time of manufacture, and excellent in heat resistance. Furthermore, the object of the present invention is to provide a polymerizable composition suitable for a transparent substrate for a touch panel that has plate cracking prevention properties and is excellent in heat resistance and transparency, a transparent substrate for a touch panel using the composition, and the substrate. It is providing the transparent electrode plate which has this, and the touchscreen which has this transparent electrode plate.

  The present invention relates to a polyfunctional (meta) having 5 to 95% by mass of a monoethylenically unsaturated monomer containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms and two or more (meth) acryloyl groups. And at least one compound selected from the group consisting of cyclohexadiene and derivatives thereof and terpenoid compounds and derivatives thereof per 100 parts by mass of a mixture consisting of 5 to 95% by mass of acrylate, and ethyl A method for producing an acrylic resin plate comprising the steps of adding 0.001 to 0.1 parts by mass of acid phosphate to form a polymerizable composition, injecting the polymerizable composition into a mold, and performing cast polymerization. .

  In addition, the present invention provides a monoethylenically unsaturated monomer 70 to 99% by mass containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, and a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms. 5 to 95 parts by mass of a syrup consisting of 1 to 30% by mass of a (co) polymer consisting of monoethylenically unsaturated monomer units containing a polyfunctional (meta) having two or more (meth) acryloyl groups ) At least one compound selected from the group consisting of cyclohexadiene and derivatives thereof and terpenoid compounds and derivatives per 100 parts by mass of a mixture consisting of 5 to 95 parts by mass of acrylate, and ethyl and 0.001 to 0.1 parts by mass of acid phosphate is added to form a polymerizable composition, and the polymerizable composition is poured into a mold. And a method for producing an acrylic resin plate having a step of performing cast polymerization.

Moreover, this invention is polyfunctional which has 15-55 mass% of monoethylenically unsaturated monomers containing the methacrylic acid alkyl ester which has a C1-C4 alkyl group, and two or more (meth) acryloyl groups. 0.015 to 0.2 parts by mass of at least one compound selected from the group consisting of cyclohexadiene and derivatives thereof and terpenoid compounds and derivatives per 100 parts by mass of a mixture consisting of 45 to 85% by mass of (meth) acrylate , Polymerizable composition for touch panel containing 0.001 to 0.1 parts by mass of ethyl acid phosphate,
Furthermore, the monoethylenically unsaturated monomer containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms further contains an alkyl ester having a methacrylic acid alkyl group having 8 to 20 carbon atoms. And a composition.

  Alternatively, monoethylenically unsaturated monomer 70 to 99% by mass containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, and mono containing an methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms 15 to 55 parts by mass of syrup consisting of 1 to 30% by mass of (co) polymer consisting of ethylenically unsaturated monomer units, and polyfunctional (meth) acrylate 45 having two or more (meth) acryloyl groups 0.015 to 0.2 parts by mass of at least one compound selected from the group consisting of cyclohexadiene and derivatives thereof and terpenoid compounds and derivatives thereof per 100 parts by mass of a mixture consisting of ˜85 parts by mass, and ethyl acid phosphate 0 It is related with the polymeric composition for touchscreens containing 0.001-0.1 mass part.

  In addition, the present invention relates to a transparent substrate for an acrylic touch panel obtained by injecting the above polymerizable composition for a touch panel into a mold and cast polymerization, and a transparent conductive material on at least one surface of the transparent substrate. The present invention relates to a transparent electrode plate formed with a film.

  The present invention further includes an upper transparent electrode plate and a lower transparent electrode plate, wherein the upper transparent electrode plate and the lower transparent electrode plate are formed on a transparent substrate and at least one surface of the transparent substrate. In the touch panel in which the upper transparent electrode plate and the lower transparent electrode plate are arranged so as to face each other, the upper transparent electrode plate and the lower transparent electrode plate At least one of the electrode plates is a transparent electrode plate as described above.

  According to the method for producing an acrylic resin plate of the present invention, since a specific composition is adopted, the heat resistance, appearance, and plate in the peeling process during production are maintained while maintaining the excellent optical properties of the acrylic resin. The crack prevention property can be greatly improved. This acrylic resin plate is suitable for, for example, nameplates of various electrical devices, various glazings such as partitions, front plates of various displays such as CRTs, liquid crystal televisions, projection televisions, etc., and front plates of information display units such as liquid crystals of information terminals. Can be used for

  In addition, according to the polymerizable composition for a touch panel of the present invention, the heat resistance that can withstand the inorganic thin film forming process and the electrode thermosetting process in the touch panel manufacturing process while maintaining the excellent optical properties inherent in the acrylic resin. And a composition that can greatly improve the appearance and plate cracking prevention in the peeling process during production. Furthermore, because the resin plate can be used for the substrate of the transparent electrode plate for the touch panel, it is possible to easily prevent damage to the touch panel, to reduce the weight, and to reduce the wall thickness. Application to shapes is possible.

<Acrylic resin plate>
Regarding the method for producing an acrylic resin plate of the present invention, first, the case where a mixture composed of a monoethylenically unsaturated monomer and a polyfunctional (meth) acrylate is used will be described. Moreover, the polymerizable composition for a touch panel of the present invention is also described.

  The mixture in this case is a polyfunctional compound having 5 to 95% by mass of a monoethylenically unsaturated monomer containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms and two or more (meth) acryloyl groups. It consists of 5 to 95 mass% of (meth) acrylate.

  Content of the monoethylenically unsaturated monomer containing the methacrylic acid alkyl ester which has a C1-C4 alkyl group is 5-95 mass% in a mixture. When the content is 5% by mass or more, the appearance is improved, and when it is 95% by mass or less, the heat resistance tends to be improved. Further, the content is preferably 10 to 55% by mass, and more preferably 15 to 50% by mass. When using as a transparent substrate for touch panels, it is preferably 15 to 55% by mass, and more preferably 20 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 when imparting high transparency to the resin plate, and the ratio of the 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 monoethylenically unsaturated monomers other than methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms include, for example, styrene, α-methylstyrene, acrylonitrile, acrylic acid, methacrylic acid, methyl acrylate, acrylic acid Ethyl, n-butyl acrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, isostearyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, isobornyl methacrylate, glycidyl methacrylate, tetrahydro methacrylate Examples include furfuryl, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, and the like. These can also be used in combination. In particular, it is preferable to reduce the water absorption for touch panel applications. For this purpose, it has 8 to 20 carbon atoms such as 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, and isostearyl methacrylate. It is preferable to use an alkyl methacrylate having an alkyl group.

  Content of the polyfunctional (meth) acrylate which has a 2 or more (meth) acryloyl group is 5-95 mass% in a mixture. When this content is 5% 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. When used as a transparent substrate for a touch panel, it is preferably 45 to 85% by mass, and more preferably 55 to 80% by mass.

  The polyfunctional (meth) acrylate having two or more (meth) acryloyl groups is a polyfunctional acrylate having two or more acryloyl groups or a polyfunctional methacrylate having two or more methacryloyl groups. These can also be used together. As this polyfunctional (meth) acrylate, for example, the following general formula (1)

(In the formula, R ¹ and R ² represent H or CH _3. )
A compound represented by the following general formula (2)

(In the formula, R ³ and R ⁴ represent H or CH ₃ , R ⁵ and R ⁶ represent H or a hydrocarbon group having 3 or less carbon atoms, and n represents an integer of 0 to 4)
, Trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane hexa (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like. These can also be used in combination.

  In these, the compound represented by General formula (1) or General formula (2) is preferable.

Examples of the compound represented by the general formula (1) include bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] decanediacrylate and bis (oxymethyl) tricyclo [5.2.1. 0 ^2,6 ] decanedimethacrylate and the like. These can also be used in combination. By using these compounds, the hygroscopicity of the obtained resin can be reduced.

  Examples of the compound represented by the general formula (2) include ethylene glycol di (meth) acrylate, 1,3-propanediol di (meth) acrylate, 1,4-butylene glycol dimethacrylate, and 1,6-hexanediol. Di (meth) acrylate, 2-methyl-1,3-propanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2,2′-dimethyl-1,4-butanediol di (meth) acrylate, etc. Is mentioned. These can also be used in combination. Of the compounds represented by the general formula (2), neopentyl glycol dimethacrylate is most preferable from the viewpoint of improving transparency.

  In general formula (2), when n is 1 or more, the appearance is good, and when n is 4 or less, the heat resistance tends to be improved. In addition, compared with the compound represented by the general formula (1), when the compound represented by the general formula (2) is used, the polymerization shrinkage tends to increase. It is preferable that it is 70 mass%. When this content is 5% by mass or more, the heat resistance is improved, and when it is 70% by mass or less, the appearance tends to be good. Furthermore, when using as a transparent substrate for touch panels, the content is preferably 45% by mass or more.

  Moreover, when using the compound represented by General formula (2) as polyfunctional (meth) acrylate, the monoethylenically unsaturated monomer containing the methacrylic acid alkyl ester which has a C1-C4 alkyl group is used. It is preferable that content is 30-95 mass% in a mixture. When the content is 30% by mass or more, the appearance is improved, and when it is 95% by mass or less, the heat resistance tends to be improved. Furthermore, when using as a transparent substrate for touch panels, it is preferable that content of the monoethylenically unsaturated monomer containing the alkyl methacrylate which has a C1-C4 alkyl group is 55 mass% or less.

  Next, the case of using a syrup composed of a monoethylenically unsaturated monomer and a (co) polymer and a mixture composed of a polyfunctional (meth) acrylate will be described.

  In this case, the mixture is composed of 70 to 99% by mass of a monoethylenically unsaturated monomer containing an alkyl methacrylate having 1 to 4 carbon atoms and an alkyl methacrylate having 1 to 4 carbon atoms. 5 to 95 parts by mass of syrup consisting of 1 to 30% by mass of a (co) polymer consisting of monoethylenically unsaturated monomer units containing an ester, and a polyfunctional compound having two or more (meth) acryloyl groups ( It is a mixture containing 5 to 95 parts by weight of (meth) acrylate.

  The content of syrup in 100 parts by mass of the mixture is 5 to 95 parts by mass. Furthermore, this content is preferably 10 to 70 parts by mass, more preferably 15 to 55 parts by mass, and even more preferably 20 to 45 parts by mass when used as a transparent substrate for a touch panel. .

  Content of the monoethylenically unsaturated monomer containing the methacrylic acid alkyl ester which has a C1-C4 alkyl group which comprises syrup is 70-99 mass% in syrup. When this content is 70% by mass or more, the heat resistance is improved, and when it is 99% by mass or less, the appearance tends to be improved. Specific examples of the methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms in the monoethylenically unsaturated monomer containing the methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, and other monoethylenic unsaturated monomers Specific examples of the saturated monomer and suitable composition ratios of the two include the same ones as described above.

  Content of the (co) polymer which comprises syrup is 1-30 mass% in syrup. When this content is 1% by mass or more, the appearance is improved, and when it is 30% by mass or less, the heat resistance tends to be improved. The (co) polymer is composed of a monoethylenically unsaturated monomer unit containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms. That is, a methacrylic acid alkyl ester homopolymer having an alkyl group having 1 to 4 carbon atoms, or an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms and a monoethylenically unsaturated monomer that can be copolymerized therewith It is a copolymer with the body. The “(co) polymer” means “homopolymer or copolymer”. Specific examples of methacrylic acid alkyl esters having an alkyl group having 1 to 4 carbon atoms used in this (co) polymer, other specific examples of monoethylenically unsaturated monomers, and suitable composition ratios of both Is the same as described above.

  Content of polyfunctional (meth) acrylate in 100 mass parts of mixtures is 5-95 mass parts. When this content is 5 parts by mass or more, the heat resistance is improved, and when it is 95 parts by mass or less, the appearance tends to be good. Furthermore, this content is preferably 30 to 90 parts by mass, more preferably 45 to 85 parts by mass, even more preferably 55 to 80 parts by mass when used as a transparent substrate for a touch panel. . Specific examples of the polyfunctional (meth) acrylate include the same as described above. Moreover, when using the compound represented by the said General formula (2) as polyfunctional (meth) acrylate, it is preferable that content of the compound is 5-70 mass parts in 100 mass parts of mixtures. When this content is 5 parts by mass or more, the heat resistance is improved, and when it is 70 parts by mass or less, the appearance tends to be good. Furthermore, when using as a transparent substrate for touch panels, the content is preferably 45 parts by mass or more.

  In the present invention, at least one selected from the group consisting of cyclohexadiene and a derivative thereof and a terpenoid compound and a derivative thereof is used per 100 parts by mass of the mixture described above. A polymerizable composition is prepared by adding 0.015 to 0.2 parts by mass of the compound and 0.001 to 0.1 parts by mass of ethyl acid phosphate.

  At least one compound selected from the group consisting of cyclohexadiene and derivatives thereof and terpenoid compounds and derivatives thereof is a component that functions as a polymerization regulator. Hereinafter, this is referred to as “compound (a)”. Examples of the compound (a) include 1,4-cyclohexadiene, 1-methyl-1,4-cyclohexadiene, α-terpinene, β-terpinene, γ-terpinene, terpinolene, limonene, myrcene, α-pinene, β-pinene, terpinol and the like can be mentioned. In particular, terpinolene is preferable.

  The amount of compound (a) added is 0.015 to 0.2 parts by mass per 100 parts by mass of the mixture. If this addition amount is 0.015 parts by mass or more, it is difficult to break the plate in the peeling step during production, and if it is 0.2 parts by mass or less, the residual monomer tends to decrease and the thermal stability tends to be good. Here, the peeling process at the time of production is a process from the end of polymerization and curing until the acrylic resin plate is peeled from the mold. Furthermore, this addition amount is preferably 0.02 to 0.15 parts by mass.

Ethyl acid phosphate is a component that functions as a release agent, and is a monoester represented by C ₂ H ₅ OP (O) (OH) ₂ , (C ₂ H ₅ O) ₂ P (O) (OH). Represented diesters or mixtures thereof. A mixture is preferred. The mixing ratio of monoester and diester is preferably 1 to 9 to 9 to 1, more preferably 3 to 7 to 7 to 3, and still more preferably 5 to 5. The amount of ethyl acid phosphate added is 0.001 to 0.1 parts by weight per 100 parts by weight of the mixture. When this addition amount is 0.001 part by mass or more, even if the resin plate is repeatedly produced, it becomes difficult to break the plate in the peeling step during production, and when it is 0.1 part by mass or less, the acrylic resin There exists a tendency for the low water absorption of a board and the surface of a resin board to become favorable. Further, this addition amount is preferably 0.005 to 0.05 parts by mass.

  Various kinds of conventionally known radical polymerization initiators can be used for the polymerization of the polymerizable composition. Specific examples of the radical polymerization initiator include t-butyl peroxypivalate, t-hexyl peroxypivalate, t-butyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, and t-butylperoxide. Oxyisopropyl carbonate, t-hexylperoxyisopropyl monocarbonate, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2 2,2'-azobisisobutyronitrile and the like. As for the addition amount of a radical polymerization initiator, 0.001-1 mass part is preferable with respect to 100 mass parts of polymeric compositions.

  Below, the method of the casting polymerization which uses methyl methacrylate as a methacrylic acid alkylester which has a C1-C4 alkyl group is illustrated. However, the present invention is not limited to this. First, methyl methacrylate, polyfunctional (meth) acrylate, (co) polymer containing methyl methacrylate units as required, and other monoethylenically unsaturated monomers copolymerizable as necessary In a suction bottle and stirred to make a mixture. A polymerization initiator, a polymerization regulator [compound (a)], and ethyl acid phosphate are added to the mixture, and vacuum deaeration is performed to obtain a polymerizable composition. This polymerizable composition is poured into a mold formed by sandwiching a gasket between a pair of tempered glass sheets, placed in a heating furnace, and polymerized at 40 to 70 ° C. for 2 to 5 hours, and at 100 to 150 ° C. for 1 to 6 hours. It can be cured and peeled 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, or 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 polymerizable composition contains the above-mentioned components as main components, but if necessary, a colorant, a mold release agent other than ethyl acid phosphate, an antioxidant, a stabilizer, an antistatic agent, an antibacterial agent, Flame retardants, impact modifiers, light stabilizers, ultraviolet absorbers, light diffusing agents, polymerization inhibitors, chain transfer agents and the like can be added as long as the effects of the present invention are not impaired. In order to further reduce the amount of residual monomer in the resulting resin plate, it is preferable to add a chain transfer agent such as mercaptan.

  In addition, the curable composition is applied and cured on at least one inner surface of the mold, and then the polymerizable mixture is injected into the mold and cast polymerization is performed, whereby the cured coating on the inner surface of the mold is applied to the resin plate surface. It is good also as an acrylic resin laminated body which makes it transfer and has a cured coating film on at least one surface. In this case, the acrylic resin laminate is excellent in scratch resistance.

  The acrylic resin plate of the present invention is greatly improved in heat resistance, appearance, shape stability, and plate crack prevention in the peeling process during production 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 of 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.

  An acrylic resin laminate in which a transparent conductive film such as ITO is formed on at least one surface of an acrylic resin plate can be used for the use of a transparent conductive material. 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.

<Transparent electrode plate for touch panel>
The transparent electrode plate for a touch panel of the present invention uses an acrylic resin plate obtained from the polymerizable composition for a touch panel of the present invention as a transparent substrate, and is formed on at least one surface of the acrylic resin plate. It has a transparent conductive film. 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 130 ° C. for 1 to 4 hours. And the sputtering process of ITO is performed in the temperature of 100-140 degreeC under a vacuum, Preferably it is 120 degreeC. Thereafter, the electrode and the lead electrode are applied with a silver paste and cured at a temperature of 130 to 170 ° C., preferably 150 ° C.

  The transparent electrode plate for a touch panel preferably has a deflection temperature under load of 150 ° C. or higher. If the deflection temperature under load is 150 ° C. or higher, the resin substrate tends to be difficult to deform when the silver paste is cured. The deflection temperature under load of the transparent electrode plate is the same as the deflection temperature under load of the acrylic resin plate constituting the transparent electrode plate when the thickness of the transparent conductive film is as thin as 1 μm or less. Therefore, in this case, the deflection temperature under load of the acrylic resin plate may be measured and used as the deflection temperature under load of the transparent electrode plate.

  0.5-2 mm is preferable and, as for the thickness of the acrylic resin board used for the transparent electrode plate for touchscreens, 0.5-1 mm is more preferable. Moreover, 10-50 nm is preferable and, as for the thickness of a transparent conductive film, 25-40 nm is more preferable. 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.

  The acrylic resin plate used for the transparent electrode plate for a touch panel is preferably uncolored. Further, an antireflection film can be formed on the side without the transparent conductive film. When the thickness of the transparent electrode plate for a touch panel is 1 mm, the total light transmittance is a value based on the total light transmittance measurement method shown in JIS-K7361, and is preferably 91% or more. If the total light transmittance is 91% or more, sufficient transparency as a transparent electrode plate for a touch panel can be obtained.

<Touch panel>
The touch panel of the present invention comprises an upper transparent electrode plate and a lower transparent electrode plate, and the upper transparent electrode plate and the lower transparent electrode plate are formed on a transparent substrate and at least one surface of the transparent substrate. A transparent electrode plate having a film, wherein the upper transparent electrode plate and the lower transparent electrode plate are arranged so as to face each other so that the transparent conductive films face each other. And at least one of this lower transparent electrode plate is the transparent electrode plate for touchscreens of this invention, It is characterized by the above-mentioned.

  Hereinafter, the suitable example of the transparent electrode plate for touchscreens of this invention and a touchscreen using the same is demonstrated using FIGS. 1-3. FIG. 1 is a schematic sectional view showing an example of the transparent electrode plate for a touch panel of the present invention, and FIG. 2 is a schematic plan view thereof. FIG. 3 is a schematic cross-sectional view showing an example of a touch panel using the transparent electrode plate shown in FIGS. 1 and 2 as a lower transparent electrode plate.

  The touch panel shown in FIG. 3 has a structure in which a lower transparent electrode plate 1 and an upper transparent electrode plate 7 are arranged to face each other with a spacer 6 therebetween. As shown in FIGS. 1 and 2, the lower transparent electrode plate 1 includes a transparent substrate 2, a transparent conductive film 3 formed on one surface of the transparent substrate 2, and end portions on the transparent conductive film 3. The electrode 4 is connected to the electrode 4, and the lead electrode 5 is connected to the electrode 4. The upper transparent electrode plate 7 has the same structure as the lower transparent electrode plate 1. That is, the upper transparent electrode plate 7 similarly has a transparent substrate 8, a transparent conductive film 9, an electrode 10, and the like.

  The lower transparent electrode plate 1 and the upper transparent electrode plate 7 have the transparent conductive films 3 and 9 inside, a dot spacer 11 interposed between the transparent electrode plates 1 and 7, and the electrodes 4 and 10. It arrange | positions through the spacer 6 at fixed intervals so that a direction may cross | intersect. When the touch panel having such a configuration is pressed from above the upper transparent electrode plate 7 with a pen or a finger, the upper transparent electrode plate 7 is deformed and the lower transparent conductive film 3 and the upper transparent conductive film 9 are brought into contact conduction. The input is complete.

  Since the transparent electrode plate for a touch panel of the present invention has high transparency and high rigidity, it is preferably used as the lower transparent electrode plate 1. 1 to 3 show such an example. However, the present invention is not limited to this. For example, the transparent electrode plate for a touch panel of the present invention may be used as the upper transparent electrode plate 7 or may be used for both the lower transparent electrode plate 1 and the upper transparent electrode plate 7.

  Hereinafter, the present invention will be described more specifically with reference to examples. In the following description, “part” is based on mass, and “%” is based on mass except for the measured value of haze. 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 heat resistance, the deflection temperature under load was measured in accordance with the measurement method shown in JIS-K7207.

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

(1-3) Plate crack prevention:
In order to evaluate plate cracking prevention properties, the production of acrylic resin plates was repeated up to 10 times with the same mold without washing the mold in the middle. Even after 10 repetitions, after the polymerization and curing were completed, the mold was cooled to 40 ° C. or lower, and “10” was indicated when the acrylic resin plate did not crack before being peeled from the mold. When a plate crack occurred when the number of repetitions was 10 times or less, the number of times before the plate crack occurred was indicated by “n”.

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

(2) Evaluation of transparent electrode plate for touch panel:
(2-1) Total light transmittance:
In order to evaluate the transparency of the transparent electrode plate for a touch panel, the total light transmittance was measured according to the measurement method shown in JIS-K7361.

(2-2) Deformation of substrate:
A series of touch panels for determining whether or not the acrylic resin laminate (substrate) is deformed, drying the substrate before forming the transparent conductive film (ITO), then forming the film by sputtering, and applying and curing the silver paste after forming the film When the acrylic resin laminate was not deformed, it was evaluated as “◯” (good), and when deformation occurred, it was evaluated as “x” (defective).

(2-3) ITO state:
The state of the transparent conductive film (ITO) was observed in a series of manufacturing processes for transparent electrode plates for touch panels such as film formation by sputtering and silver paste coating and curing after film formation, and optical distortion and cracks were observed. When it was not, it was evaluated as “◯” (good), and when optical distortion or crack was observed, it was evaluated as “x” (bad).

(2-4) Adhesiveness:
Using a cutter, scratches are made on the transparent conductive film of the transparent electrode plate for touch panels in a grid pattern of 11 pieces vertically and horizontally at intervals of 1 mm so as to reach the cured coating, and 100 squares of 1 × 1 mm are produced. did. Adhesive tape (Nichiban, trade name “Cerotape”) was closely adhered on the mesh, and was peeled off rapidly 45 ° forward. 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, more preferably 100. It can be said that the larger the value of n, the higher the adhesiveness of the transparent conductive film, and the better the transparent electrode plate for touch panel.

<Manufacture of acrylic resin plate>
[Example 1]
10 parts of isostearyl methacrylate (made by Shin-Nakamura Chemical Co., Ltd., trade name “NK ester S-1800M”), 10 parts of methyl methacrylate, and bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] Per 100 parts of a mixture with 80 parts of decanedimethacrylate, 0.05 part of 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile) as a polymerization initiator, and 0.0 part of t-hexylperoxypivalate. 05 parts, 0.05 part of t-hexylperoxyisopropyl monocarbonate, 0.03 part of terpinolene, 0.01 part of ethyl acid phosphate (manufactured by Johoku Chemical Industry Co., Ltd., trade name “JP-502”) are mixed, and the suction bottle is mixed. The mixture was stirred in and vacuum degassed to obtain a polymerizable composition.

  This polymerizable composition 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 bubbles, placed in a heating furnace, and placed in a heating furnace for 1 hour at 55 ° C and 1 at 50 ° C. Polymerization was carried out for 3 hours at 135 ° C. Thereafter, the mold was cooled to 40 ° C. or lower and peeled off, and heated at 130 ° C. for 4 hours to obtain an acrylic resin plate having a thickness of 1 mm. When this acrylic resin plate was repeatedly produced without washing the mold, the acrylic resin plate was not cracked during cooling after polymerization and curing, even after being repeated 10 times. No cracking occurred. Further, this resin plate had a good appearance without whitening or sinking. Further, the haze was measured and found to be 0.2%, indicating good transparency. The deflection temperature under load exceeded 200 ° C. Table 1 shows main raw material compositions and evaluation results of the polymerizable composition of this example.

[Examples 2 to 21, Comparative Examples 1 to 14]
An acrylic resin plate was produced in the same manner as in Example 1 except that the polymerizable composition comprising the raw material compositions shown in Tables 1 to 5 was employed. The evaluation results are shown in Tables 1-5.

<Transparent electrode plate>
Each acrylic resin laminate obtained in Examples 1 to 21 and Comparative Examples 1 to 14 was washed with pure water, placed in a hot air drying furnace, and dried in the atmosphere at 120 ° C. for 2 hours. Next, ITO was formed as a transparent conductive film on the resin plate by sputtering to obtain a transparent electrode plate. 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 120 ° C.

<Manufacture of transparent electrode plate for touch panel>
Each of the transparent electrode plates is cut into a width of 250 mm and a length of 180 mm, and a silver paste is applied to the transparent electrode plate in a predetermined pattern and cured at 150 ° C. to form electrodes and lead electrodes. The touch panel having the configuration shown in FIGS. A transparent electrode plate for each was manufactured. The film thickness of this electrode and the lead electrode was adjusted to about 10 μm. The evaluation result of each obtained transparent electrode plate for touch panels is shown in Tables 1-5.

<Touch panel>
Each of the touch panel transparent electrode plates was used as the lower transparent electrode plate 1 to fabricate touch panels having the configuration shown in FIG. Specifically, each of the transparent electrode plates for a touch panel was used as the lower transparent electrode plate 1. As the upper transparent electrode plate 7, an ITO film having a film thickness of about 25 nm is formed on a polyethylene terephthalate film (product name “Tetron Film” manufactured by Teijin Limited) with a thickness of 188 μm by the same method as the lower transparent electrode plate. What was formed into a film was used. As the spacer 6, a double-sided tape having a thickness of 100 μm was used.

  Further, the lower transparent conductive film 3 is coated with a photocurable acrylic resin in a predetermined pattern and cured by irradiating with ultraviolet rays, whereby dot spacers 11 having a height of 10 μm and a diameter of 50 μm are staggered at a pitch of 3 mm. It was formed so that it might be arranged in. Further, an insulating film (not shown) was formed on the electrode 4 and the electrode 10. Then, by assembling a structure in which the lower transparent electrode plate 1 and the upper transparent electrode plate 7 are arranged to face each other with a spacer 6 therebetween, a touch panel having a size corresponding to 12 types, that is, 250 mm wide × 180 mm long is manufactured. did.

The abbreviations in the table indicate the following compounds.
“MMA”: methyl methacrylate “ISMA”: isostearyl methacrylate “TDMA”: bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane dimethacrylate “PMMA”: number average molecular weight 450,000 Methyl methacrylate polymer “NPG”: Neopentylglycol dimethacrylate “EAP”: Ethyl acid phosphate “DEG”: Diethylene glycol “142D”: “Megafuck 142D” (trade name, manufactured by Dainippon Ink & Chemicals, Inc.)
“AOT”: Sodium di (2-ethylhexyl) sulfosuccinate (manufactured by Mitsui Cytec)
"BAP": Butyl acid phosphate (manufactured by Johoku Chemical Industry Co., Ltd.)
“LCA”: “Viewlight LCA-H” (trade name, manufactured by Sanyo Chemical Industries)

  As shown to Tables 1-3, in Examples 1-21, the favorable result was obtained about the heat resistance of the acrylic resin board, transparency, external appearance, and board crack prevention property. Furthermore, in Examples 1-9 and 12-19, the favorable result was obtained about transparency, external appearance, and adhesiveness of the transparent electrode plate for touch panels. The touch panel also worked properly.

  On the other hand, as shown in Tables 4 and 5, in Comparative Examples 1, 2, and 4 to 13, when the acrylic resin plate was repeatedly produced using the same mold without washing the mold in the middle, the acrylic resin A plate crack occurred during the peeling process of the plate. In Comparative Example 3, the appearance of the acrylic resin plate deteriorated. Moreover, in Comparative Example 14, the heat resistance of the acrylic resin plate was low.

It is typical sectional drawing which shows an example of the transparent electrode plate for touchscreens obtained by this invention. It is a schematic plan view which shows an example of the transparent electrode plate for touchscreens obtained by this invention. It is typical sectional drawing which shows an example of the touchscreen which uses the transparent electrode plate shown in FIG. 1 and FIG. 2 as a lower transparent electrode plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower transparent electrode plate 2 Transparent substrate 3 Transparent conductive film 4 Electrode 5 Lead electrode 6 Spacer 7 Upper transparent electrode plate 8 Transparent substrate 9 Transparent conductive film 10 Electrode 11 Dot spacer

Claims (8)

  5 to 95% by mass of a monoethylenically unsaturated monomer containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, and a polyfunctional (meth) acrylate 5 having two or more (meth) acryloyl groups 0.015 to 0.2 parts by mass of at least one compound selected from the group consisting of cyclohexadiene and derivatives thereof, and terpenoid compounds and derivatives thereof per 100 parts by mass of a mixture consisting of 95% by mass; A method for producing an acrylic resin plate comprising a step of containing 001 to 0.1 parts by mass to form a polymerizable composition, injecting the polymerizable composition into a mold, and performing cast polymerization.   Monoethylenic unsaturated monomer containing 70 to 99% by mass of monoethylenically unsaturated monomer containing alkyl ester having 1 to 4 carbon atoms and monoethylenic monomer containing alkyl ester of methacrylate having 1 to 4 carbon atoms 5 to 95 parts by mass of syrup consisting of 1 to 30% by mass of (co) polymer consisting of unsaturated monomer units, and 5 to 95 polyfunctional (meth) acrylates having two or more (meth) acryloyl groups And at least one compound selected from the group consisting of cyclohexadiene and derivatives thereof, and terpenoid compounds and derivatives thereof, and 0.01 to 0.2 parts by mass of ethyl acid phosphate per 100 parts by mass of the mixture consisting of -0.1 parts by mass to form a polymerizable composition, the polymerizable composition is poured into a mold, and cast polymerization Method for producing an acrylic resin plate having a step of performing.   15 to 55% by mass of a monoethylenically unsaturated monomer containing a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, and a polyfunctional (meth) acrylate 45 to 5 having two or more (meth) acryloyl groups Per 100 parts by mass of a mixture of 85% by mass, at least one compound selected from the group consisting of cyclohexadiene and derivatives thereof and terpenoid compounds and derivatives thereof, and 0.01 to 0.2 parts by mass of ethyl acid phosphate, The polymeric composition for touchscreens containing 001-0.1 mass part.   The monoethylenically unsaturated monomer containing a methacrylic acid alkyl ester having a C1-4 alkyl group further contains a methacrylic acid alkyl ester having a C8-20 alkyl group. Item 4. The polymerizable composition for a touch panel according to item 3.   Monoethylenic unsaturated monomer containing 70 to 99% by mass of monoethylenically unsaturated monomer containing alkyl ester having 1 to 4 carbon atoms and monoethylenic monomer containing alkyl ester of methacrylate having 1 to 4 carbon atoms 15 to 55 parts by mass of syrup consisting of 1 to 30% by mass of (co) polymer consisting of unsaturated monomer units, and polyfunctional (meth) acrylates 45 to 85 having two or more (meth) acryloyl groups And at least one compound selected from the group consisting of cyclohexadiene and derivatives thereof, and terpenoid compounds and derivatives thereof, and 0.01 to 0.2 parts by mass of ethyl acid phosphate per 100 parts by mass of the mixture consisting of Polymeric composition for touchscreens containing -0.1 mass part.   The transparent substrate for acrylic touch panels obtained by inject | pouring the polymerizable composition for touchscreens of any one of Claim 3 thru | or 5 in a casting_mold | template, and cast polymerization.   A transparent electrode plate in which a transparent conductive film is formed on at least one surface of the transparent substrate for an acrylic touch panel according to claim 6.   A transparent electrode comprising an upper transparent electrode plate and a lower transparent electrode plate, the upper transparent electrode plate and the lower transparent electrode plate having a transparent substrate and a transparent conductive film formed on at least one surface of the transparent substrate In the touch panel in which the upper transparent electrode plate and the lower transparent electrode plate are arranged so as to be opposed to each other, the upper transparent electrode plate and the lower transparent electrode plate At least one is the transparent electrode plate of Claim 7, The touch panel characterized by the above-mentioned.

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