JP4558289B2 - Acrylic resin, resin plate and manufacturing method thereof, transparent electrode plate for touch panel, and touch panel - Google Patents

Description

  The present invention relates to an acrylic resin having good heat resistance, appearance, and shape stability, a resin plate made of the acrylic resin and a method for producing the same, and a transparent substrate excellent in heat resistance, transparency, and conductive film adhesion The present invention relates to a transparent electrode plate for a touch panel and a touch panel having the transparent electrode plate.

<Acrylic resin plate>
Acrylic resin plates are used in lenses, automobile parts, lighting parts, various electronic displays and the like because of their excellent optical properties. However, acrylic resin plates have the disadvantages that heat resistance is insufficient when heat treatment is performed at high temperatures, and that shape changes such as warpage are likely to occur due to water absorption.

  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). For the purpose of improving heat resistance and appearance, a method of polymerizing a composition containing methyl methacrylate and polyfunctional (meth) acrylate has been proposed (see, for example, Patent Document 2). However, these methods usually cannot provide sufficient heat resistance and shape stability. In order to obtain sufficient heat resistance by these methods, 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. Furthermore, the obtained resin molded product also tends to warp due to water absorption.

  In addition, for the purpose of improving heat resistance and appearance, a composition comprising an alkyl methacrylate monomer and a (meth) acrylate crosslinking agent and polymerizing a part thereof, and an alkyl methacrylate syrup and a crosslinking agent A method of casting polymerizing an object 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 polymerizability of the allyl group is poor and sufficient heat resistance tends not to be obtained.

<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 6, 7, and 8). However, the transparent substrate using a resin plate such as polyethylene terephthalate resin disclosed in Patent Documents 6, 7, and 8 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.

Also disclosed is a methacrylic resin molding material obtained by polymerizing methyl methacrylate and neopentyl glycol dimethacrylate, which is a polyfunctional (meth) acrylate, as monomers (see, for example, Patent Document 9). 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 9 has a low polymerization rate of 4 to 62% by mass, when this molding material is made into a product, the polymerization rate is further increased by a process such as compression molding or extrusion molding. 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 2000-276301 A JP 2001-14951 A JP 2001-34418 A Japanese Patent Publication No. 5-6570

An object of the present invention is to provide heat resistance, appearance, shape stability is good acrylic resins or Ranaru acrylic resin plate and a manufacturing method thereof. Furthermore, the objective of this invention is providing the transparent electrode plate for touchscreens which has a transparent substrate excellent in heat resistance, transparency, and thin film adhesiveness, and the touchscreen which has this transparent electrode plate.

（式中、Ｒ¹はＨまたはＣＨ₃を示す。） The present invention relates to a monoethylenically unsaturated monomer comprising 3 to 30% by mass of a methacrylic acid alkyl ester unit having an alkyl group having 8 to 20 carbon atoms and a methacrylic acid alkyl ester unit having an alkyl group having 1 to 4 carbon atoms. and body unit 2 to 35 wt%, an acrylic resin plate made of acrylic resin containing a polyfunctional (meth) acrylate units of 3 5 to 95 mass% derived from a compound represented by the following general formula (1) is there.

(In the formula, R ¹ represents H or CH _3. )

Furthermore, the present invention provides a monoethylenically unsaturated monomer comprising 3 to 30% by mass of a methacrylic acid alkyl ester having an alkyl group having 8 to 20 carbon atoms and a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms. It is a manufacturing method of the acrylic resin board which has the process of superposing | polymerizing and hardening the polymeric mixture containing 2-35 mass% and the compound 3 5-95 mass% shown by the said General formula (1).

  Furthermore, this invention is an acrylic resin laminated body formed by forming a transparent conductive film on at least one surface of the said acrylic resin board.

  Furthermore, this invention is a transparent electrode plate for touch panels which has the said acrylic resin laminated body.

  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. A transparent electrode plate, wherein the upper transparent electrode plate and the lower transparent electrode plate are arranged at intervals such that the transparent conductive films face each other, the upper transparent electrode plate and At least one of the lower transparent electrode plates is a touch panel that is the transparent electrode plate for a touch panel.

In the acrylic resins or Ranaru acrylic resin plate and a manufacturing method of the present invention, because it uses a specific composition, while maintaining excellent optical properties inherent acrylic resin, further heat resistance, Appearance and shape stability can be greatly improved. In addition, an acrylic resin laminate formed by forming a transparent conductive film such as an ITO film on the acrylic resin plate is very useful as a transparent electrode plate for a touch panel.

  The transparent electrode plate for a touch panel of the present invention has heat resistance that can withstand an inorganic thin film forming process and an electrode thermosetting process while maintaining the excellent optical properties inherent in acrylic resins, and has extremely thin film adhesion. Since it is excellent, the surface treatment of the resin substrate is not required. 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 and resin plate>
The acrylic resin used in the present invention is monoethylene containing 3 to 30% by mass of a methacrylic acid alkyl ester unit having an alkyl group having 8 to 20 carbon atoms and a methacrylic acid alkyl ester unit having an alkyl group having 1 to 4 carbon atoms. sex and unsaturated monomer units 2 to 35 wt%, is intended to include a polyfunctional (meth) acrylate units of 3 5 to 95 mass% derived from a compound represented by the general formula (1).

  Here, the content of each unit is a value indicating the overall proportion of monomer units of one or more polymers constituting the resin. That is, the acrylic resin of the present invention may be a resin composed of one kind of copolymer obtained by copolymerizing together three monomers constituting each unit described above, A resin obtained by polymerizing at least a part of at least one of the three monomers constituting the unit and polymerizing the remaining monomers in the presence of the polymer may be used. The resin in the latter case can be obtained, for example, by polymerizing a syrup comprising a (co) polymer of alkyl methacrylate and a desired monomer.

  Content of the methacrylic acid alkylester unit which has a C8-C20 alkyl group is 3-30 mass% in resin. When this content is 3% by mass or more, shape stability is improved, and when it is 30% by mass or less, heat resistance tends to be improved. This content is further preferably 5 to 20% by mass.

  Examples of the methacrylic acid alkyl ester unit having an alkyl group having 8 to 20 carbon atoms include units derived from 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, isostearyl methacrylate, and the like. These can also be used in combination.

  Content of the monoethylenically unsaturated monomer unit containing the methacrylic acid alkylester unit which has a C1-C4 alkyl group is 2-35 mass% in resin. When the content is 2% by mass or more, the appearance is improved, and when it is 35% by mass or less, heat resistance and shape stability tend to be improved. This content is preferably 5 to 25% by mass. Moreover, when the total amount of the monoethylenically unsaturated monomer unit containing the methacrylic acid alkyl ester unit which has a C1-C4 alkyl group is 100 mass parts, the methacrylic acid which has a C1-C4 alkyl group The proportion of the alkyl ester unit is preferably 50 parts by mass or more, and the proportion of the other monoethylenically unsaturated monomer units 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 methacrylic acid alkyl ester unit having an alkyl group having 1 to 4 carbon atoms include, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, Examples thereof include units derived from t-butyl methacrylate. These can also be used in combination. Among them, a methyl methacrylate unit is particularly preferable.

  The monoethylenically unsaturated monomer unit other than the methacrylic acid alkyl ester unit having an alkyl group having 1 to 4 carbon atoms includes various units other than the methacrylic acid alkyl ester unit having an alkyl group having 8 to 20 carbon atoms. Can be mentioned. For example, styrene, α-methylstyrene, acrylonitrile, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, cyclohexyl methacrylate, benzyl methacrylate, isobornyl methacrylate, glycidyl methacrylate, tetrahydromethacrylate Examples include units derived from furfuryl, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, and the like. These can also be used in combination.

The content of the polyfunctional (meth) acrylate units of which are derived from a compound represented by the general formula (1) is, in the resin, is 35 to 95 mass%. 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.

Examples of the polyfunctional (meth) acrylate, lower following general formula (1)

（式中、Ｒ¹はＨまたはＣＨ₃を示す。）
で示される化合物を使用する。

(In the formula, R ¹ represents H or CH _3. )
The compound shown by is used .

In these, the compound unit shown by General formula (1) is preferable. Examples of 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 ] decane dimethacrylate. These can also be used in combination.

Acrylic resin This is a resin containing each monomer unit described above as a main structural unit. The resin that is used as the acrylic resin plate.

  The acrylic resin plate of the present invention is greatly improved in heat resistance, appearance, 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.

The method for producing an acrylic resin plate according to the present invention includes a monomethacrylate comprising 3 to 30% by mass of a methacrylic acid alkyl ester having 8 to 20 carbon atoms and a methacrylic acid alkyl ester having 1 to 4 carbon atoms. with ethylenically unsaturated and monomer 2 to 35% by weight, the polymerization mixture the step of polymerizing and curing comprising a compound 3 5-95 weight% represented by the general formula (1). Specific examples of each monomer used here are as 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.

  For the polymerization of the polymerizable mixture, conventionally known various radical initiators can be used. Specific examples of the radical initiator include t-butyl peroxypivalate, t-hexyl peroxypivalate, t-butyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, t-butylperoxy. Isopropyl carbonate, t-hexylperoxyisopropyl monocarbonate, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2, Examples include 2'-azobisisobutyronitrile.

  The following is a method of cast polymerization using isostearyl methacrylate as the alkyl methacrylate having 8 to 20 carbon atoms and methyl methacrylate as the alkyl methacrylate having 1 to 4 alkyl groups. Illustrate. However, the present invention is not limited to this.

  First, isostearyl methacrylate, methyl methacrylate, polyfunctional (meth) acrylate, (co) polymer containing methyl methacrylate units as required, and other monoethylenic copolymerizable if necessary The unsaturated monomer is charged into a suction bottle and stirred to obtain a mixture. A radical polymerization initiator is added to the mixture and vacuum deaeration is performed. This mixture is poured into a mold formed 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. The acrylic resin plate can be obtained by peeling from the mold.

  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 of the present invention 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 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, a chain transfer agent, and the like can be added.

<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.

  Moreover, the acrylic resin laminated body which formed transparent conductive films, such as ITO, on at least one surface on the acrylic resin board of this invention can be utilized 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 such as 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 has the acrylic resin plate of the present invention as a transparent substrate, and a transparent conductive film formed on at least one surface of the acrylic resin plate. 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 employed, it is possible to reduce the weight and thickness as compared with a 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. 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) 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 by n / 10.

(2) Evaluation of acrylic resin laminate:
(2-1) Warpage amount:
In order to evaluate the shape stability of the acrylic resin laminate, a shape stability test was performed to measure the amount of warpage. Specifically, a sample of 190 mm × 190 mm × 1.0 mm (thickness) is left in a constant temperature and humidity chamber at 23 ° C. and 50% RH for one day, and then placed in a constant temperature and humidity chamber at 60 ° C. and 90% RH. It was hung with a clip and allowed to stand for 10 days, again left in a constant temperature and humidity room at 23 ° C. and 50% RH for 1 hour, then cooled, and the amount of warpage was measured. In the measurement of the amount of warpage, the sample is placed on a horizontal board in a direction that is convex upward, and the distance a (mm) from the board surface to the lower side of the part farthest from the board surface is measured with a caliper, The ratio of the distance to the sample length was defined as the amount of warpage (%). That is,
Warpage (%) = a / 190 × 100
It becomes. Here, in the case of a convex warp on the transparent conductive film side, the warp amount is represented as a positive value, and in the case of a concave warp on the transparent conductive film side, the warp amount is represented as a negative value.

(3) Evaluation of transparent electrode plate for touch panel:
(3-1) 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.

(3-2) Deformation of substrate:
For a series of touch panels, whether or not the acrylic resin plate (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 The transparent electrode plate was observed with the naked eye, and when the acrylic resin plate was not deformed, it was evaluated as “◯” (good), and when it was deformed, it was evaluated as “x” (bad).

(3-3) 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).

(3-4) Adhesiveness:
Using a cutter, scratches were 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 resin substrate, and 100 squares of 1 × 1 mm were produced. . Adhesive tape (manufactured by Nichiban Co., Ltd., cellophane tape) was closely adhered on the mesh, and was peeled off rapidly by 45 °. 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]
Isostearyl methacrylate (manufactured by Shin Nakamura Chemical Co., Ltd. "NK Ester S-1800M") and 10 parts, and 10 parts of methyl methacrylate, bis (oxymethyl) tricyclo [5,2,1,0 ^2,6] Dekanji Per 100 parts of a mixture with 80 parts of methacrylate, 0.05 part of 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile) as a polymerization initiator, 0.05 part of t-hexylperoxypivalate, 0.05 part of t-hexylperoxyisopropyl monocarbonate and 0.03 part of terpinolene were mixed, charged into a suction bottle and stirred, and vacuum deaeration was performed 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 off, and heated at 130 ° C. for 4 hours to obtain an acrylic resin plate having a thickness of 1 mm.

  This resin plate had a good appearance without whitening or sink marks. 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 the main raw material composition and evaluation results of the polymerizable mixture of this example.

[Example 2-9, Comparative Example 1-6]
An acrylic resin plate was produced in the same manner as in Example 1 except that the raw material compositions shown in Table 1 and Table 2 were adopted. The evaluation results are shown in Tables 1 and 2.

<Deposition of transparent conductive film>
Each acrylic resin plate obtained in Examples 1 to 9 and Comparative Examples 1 to 6 was washed with pure water, placed in a hot air drying furnace, and dried with hot air at 120 ° 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 120 ° C. Tables 1 and 2 show the amounts of warpage of the obtained acrylic resin laminates after the shape stability test.

<Manufacture of transparent electrode plate for touch panel>
Each of the acrylic resin laminates is cut into a width of 250 mm and a length of 180 mm, and a silver paste is applied thereto in a predetermined pattern and cured at 150 ° C. to form an electrode and a lead electrode. The configuration shown in FIGS. 1 and 2 Each of the transparent electrode plates for touch panels was manufactured. The film thickness of this electrode and the lead electrode was adjusted to about 10 μm. Tables 1 and 2 show the evaluation results of the obtained transparent electrode plates for touch panels.

<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 188 μm thick polyethylene terephthalate film (product name: Tetron film, manufactured by Teijin Ltd.) in the same manner as the lower transparent electrode plate. What was done 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.

表１に示すように、実施例１〜９では、アクリル系樹脂板の耐熱性、透明性、外観、アクリル樹脂積層体の形状安定性、タッチパネル用透明電極板の透明性、外観、密着性について良好な結果が得られた。また、タッチパネルも正常に動作した。

As shown in Table 1, in Examples 1 to 9 , heat resistance, transparency, appearance of acrylic resin plate, shape stability of acrylic resin laminate, transparency, appearance, adhesion of transparent electrode plate for touch panel Good results were obtained. The touch panel also worked properly.

  On the other hand, as shown in Table 2, in Comparative Examples 1 to 4, the amount of warpage of the acrylic resin laminate was large and the shape stability was poor. In Comparative Examples 5 and 6, the acrylic resin plate has low heat resistance, and deformation occurs during heating at 120 ° C. during ITO film formation or 150 ° C. during electrode formation, which is unsuitable for a touch panel. there were.

It is typical sectional drawing which shows an example of the transparent electrode plate for touchscreens of this invention. FIG. 2 is a schematic plan view thereof. It is a schematic plan view which shows an example of the transparent electrode plate for touchscreens of 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 (7)

Monoethylenically unsaturated monomer units 2 to 3 containing 3 to 30% by mass of methacrylic acid alkyl ester units having an alkyl group having 8 to 20 carbon atoms and methacrylic acid alkyl ester units having an alkyl group having 1 to 4 carbon atoms. An acrylic resin plate made of an acrylic resin containing 35% by mass and 35 to 95% by mass of a polyfunctional (meth) acrylate unit derived from a compound represented by the following general formula (1).

(In the formula, R ¹ represents H or CH _3. ) Monoethylenically unsaturated monomer 2 to 35% by mass containing 3 to 30% by mass of methacrylic acid alkyl ester having an alkyl group having 8 to 20 carbon atoms and methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms And the manufacturing method of the acrylic resin board which has the process of superposing | polymerizing and hardening the polymeric mixture containing 35-95 mass% of compounds shown by following General formula (1).

(In the formula, R ¹ represents H or CH _3. ) Acrylic resin laminate obtained by forming a transparent conductive film in claim 1 Symbol placement on at least one surface of the acrylic resin plate. The acrylic resin laminate according to claim 3 , wherein the transparent conductive film is an ITO film. The transparent electrode plate for touchscreens which has the acrylic resin laminated body of Claim 3 or 4 . The transparent electrode plate for a touch panel according to claim 5 , wherein the deflection temperature under load is 150 ° C or higher. 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 A touch panel in which 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, the upper transparent electrode plate and the lower transparent electrode plate A touch panel, wherein at least one of the transparent electrode plates for a touch panel according to claim 5 or 6 .

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