JP4217766B2 - Touch panel with laminated hard coat film - Google Patents

Description

【００２７】
製造例５〜７
製造例２〜４において、ポリエステル・フィルムの非冷却面に換えて冷却面にアンカーコート及び紫外線硬化性樹脂のハードコートを施した点を除いてはこれらの実施例と同様にして、透明ハードコート・フィルム得た。
このフィルムについても、製造例１〜４と同様の事項を測定した。その結果を表−２に示す。
【００２８】
【表２】

【００２９】
製造例８〜１１
厚さ１２５μのポリカーボネート・フィルム（製造例８及び９）、及び同じくポリエステルスルフォン・フィルム（製造例１０及び１１）のシートに紫外線硬化性樹脂をワイヤーバーを用いて塗布した後、紫外線で硬化して３μ（製造例８及び１０）及び５μ（製造例９及び１１）のハードコート層を形成した。
このフィルムについても鉛筆硬度、反り、全光線透過率及びヘイズを測定した。その結果を表−３に示す。
【００３０】
【表３】

【００３１】
実施例１及び２
製造例１及び３の透明ハード・コートフィルムを使用し、このフィルムのハードコート層と反対の面に２５μのポリアクリル酸エステルからなる粘着剤を塗布し、タッチパネルの表面に重ね合わせて圧着ロールに通し、さらに、温度１５０℃で３０分間加熱した後室温に急冷して、ハードコート・フィルムを積層したタッチパネルを製造した。
【００３２】
比較例１及び２
製造例５及び６の透明ハードコート・フィルムを用い、これを実施例１及び２と同様にしてタッチパネルに積層した。
実施例１及び２と、比較例１及び２で得られたタッチパネルの状態を調べ、結果を表−４に示す。表 ４において、「殆どなし」とは全くみられないか、みられるとしても１０ｃｍ×１０ｃｍ当たり５個以下である場合をいう。
【００３３】
【表４】

【００３４】
表−４から明らかなとおり、実施例１及び２と比較例１及び２で得られたタッチパネルには、ハードコート層のクラックが殆どみられなかった。また、実施例１及び２のタッチパネルには、気泡のかみ込み、フィルムの浮き、剥がれもみられなかった。ただ、比較例１及び２のタッチパネルには、フィルムの浮き、剥がれ、気泡のかみ込みが若干みられたが、これは、使用する透明ハードコート・フィルムの選択、反りの矯正により解消される問題である。[0001]
[Industrial application fields]
The present invention relates to a touch panel manufacturing method for a touch panel of various displays such as CRT (cathode ray tube), LCD (liquid crystal display) and the like, which is prevented from being damaged by laminating a hard coat film on the surface. Specifically, it relates to laminating a transparent hard coat film on the surface of the touch panel after the touch panel is formed .
[0002]
[Prior art]
The touch panel is a device that inputs data by directly touching the display screen with a finger, a pen, or the like. In recent years, various displays visualized with the development of electronic devices have increased, and visualized touch panels have been used in various fields because information input operations are simple.
[0003]
The touch panel uses a polymer transparent film as a substrate, cuts a transparent conductive film formed by sputtering or other means on one side of the transparent conductive thin film such as indium tin oxide (ITO), and forms a circuit by a conventional method. Manufactured by doing. It is also known to apply a hard coat in order to improve the scratch resistance of the outer surface touched by a finger, pen, or the like.
[0004]
A conventional hard coat is applied at the stage of a transparent conductive film before being processed into a touch panel, and a hard coat layer is directly formed on one side of a transparent film to be a substrate, or a transparent with a hard coat layer provided. A transparent conductive film in which a hard coat layer is formed by laminating a hard coat film and a transparent conductive thin film layer is formed on the opposite side surface is usually produced as a roll-shaped product, which is a sheet having a desired size. It is formed into a touch panel.
[0005]
A typical example of the process from the hard-coated transparent conductive film to the formation of the touch panel is shown below.
1. Cutting (by cutting method, punching method, etc.)
2. Heat treatment Circuit printing Etching 5. 5. Washing with water Drying 7. 7. Conductive paste printing 8. Heat or UV curing 10. Dot spacer printing 10. Heat or UV curing Uncut cutting 12. Hard terminal mounting 13. Assembly 14. Inspection [0006]
[Problems to be solved by the invention]
Thus, the problem of the conventional touch panel formed from the transparent conductive film provided with the hard coat layer is that cracks (cracks) are observed in the hard coat layer.
According to the present inventors, such cracks in the hard coat layer can occur when cutting a transparent conductive film provided with a hard coat layer for touch panel formation, or when subjected to bending with a small radius of curvature. Sex has been predicted. In addition, if there are cracks generated in this way, the surface of the film is damaged by the chemical solution in the subsequent etching process, and it is also predicted that such cracks and scratches will be expanded by heat in the subsequent heating process. It was.
[0007]
Therefore, the present inventors considered to apply a hard coat after forming the touch panel in order to solve such a problem that occurs during the formation of the touch panel.
Accordingly, an object of the present invention is to provide a touch panel that solves the problem of cracks in a hard coat layer in the prior art.
[0008]
[Means for Solving the Problems]
The present invention relates to a method for applying a hard coat by laminating a transparent hard coat film on the surface of a touch panel once formed, whereby a hard coat layer is formed during touch panel formation in a conventional touch panel. This is a solution to the problem of cracks occurring as a cause.
[0009]
The transparent hard coat film used in the present invention is obtained by forming a hard coat layer on one side of a transparent film to be a substrate.
[0010]
Examples of the transparent film serving as a substrate include polyester films, polycarbonate films, polyester sulfone films, and the like.
The polyester film is formed by melt-extruding a polyester obtained by reacting a dibasic acid and a glycol, preferably polyethylene terephthalate, polyethylene isophthalate, polytetramethylene terephthalate, polytetramethylene isophthalate or the like alone A polymer and a copolymer having a main repeating unit as a constituent unit, or a polymer mixture mainly composed of these polyesters. In addition, polyester copolymers obtained from terephthalic acid, ethylene glycol, and ethylene oxide adducts such as propylene glycol and bisphenol A as the third component can also be used.
[0011]
Polyesters useful for transparent films are particularly preferred, having a reduced specific viscosity of at least 0.2 dl / g measured at 25-30 ° C. using a mixed solvent of chlorochlorophenol or phenol; tetrachloroethane = 6: 4. Is 0.5 to 1.3 dl / g.
[0012]
Hard coat layer formed on one surface of the transparent film is a thermosetting resin, an ultraviolet curable resin, a resin such as electron beam curable resin is applied to form cured.
The thermosetting resin is a resin such as epoxy, melamine, acrylic, ester, epoxy melamine, ester melamine, acrylic melamine, urethane, alkyd, silicon, carbon functional silane, or silicon functional silane.
The ultraviolet ray and electron beam curable resin is a resin formed of a compound having a functional group that causes a crosslinking reaction by ultraviolet rays or an electron beam, represented by a polyfunctional acrylic resin or the like.
[0013]
These resins can be applied to the transparent film by a known coating method. That is, gravure roll coating, Mayer bar coating, doctor blade coating, reverse roll coating, Eyanay coating, kiss coating, fountain coating, calendar coating, and the like.
In application, it is generally used in the form of a solution, an emulsion or the like. After the resin is applied to the transparent film, it is cured by heating, ultraviolet irradiation or electron beam irradiation, or a combination thereof.
[0014]
Cured resin of the hard coat layer is required stiffness that can achieve the object of abrasion resistance, the pencil hardness, scratch Pencil manual scraping method was measured in accordance with general coating test method JIS K5400 The value is desirably 2H or more. More preferably, it is 3H or more. At 3H or higher, there is almost no damage even when rubbed with steel wool.
[0015]
The transparent hard coat film used in the present invention thus obtained is then laminated on the formed touch panel, but when the film warps due to heating / quenching is large, it peels off after the lamination process, floats, etc. In some cases, wrinkles may occur during lamination processing, or air may not be discharged and air bubbles may remain. However, even in such a case, the object of the present invention for preventing cracks is still achieved.
What is suitable as the transparent hard coat film used in the present invention is a range of +5 mm to -10 mm in warpage of the film when heated at 150 ° C. ± 10 ° C. for 30 minutes according to the measurement method described later and then suddenly brought to room temperature. Is preferable, and more preferably within a range of ± 0 mm to −5 mm. When the warp is too large, or when the direction of the warp is not preferable, a treatment for correcting the warp can be performed prior to the lamination process.
[0016]
As a means for correcting the warp of the transparent hard coat film, for example, a non-coated surface of the hard coat film is coated with a resin such as thermosetting, ultraviolet curable, or electron beam curable, and cured to form a coating film. There are means such as forming. As the resin used for the coating film on the surface opposite to the hard coat layer, for example, the same resin as the hard coat layer on the surface can be used.
[0017]
Lamination | stacking to the touchscreen of the transparent hard coat film used by this invention is performed by sticking, for example. In this case, various adhesives can be used, but pressure sensitive adhesives are common.
Pressure sensitive adhesives include natural rubber, synthetic isoprene rubber, SBR, polyisobutylene, NBR, polyvinyl ether, polyacryl, polyacrylic acid ester, or a copolymer thereof, styrene / isoprene / styrene / butadiene / block copolymer Examples thereof include elastic bodies such as coalescence, silicone, polyterpene, rosin and derivatives thereof, coumarone-indene resin, and petroleum hydrocarbon resin.
[0018]
【The invention's effect】
The touch panel formed by laminating the transparent hard coat film used in the present invention hardly showed cracks in the hard coat layer often seen in conventional products. Therefore, it should be said that the industrial significance is great in that the occurrence of defective products in the processing process can be suppressed.
[0019]
[Measuring method]
1) Pencil hardness It was expressed as a pencil scratch value by a hand-scratching method measured according to the paint general test method of JIS K5400. The pencil used was a Mitsubishi pencil uni for pencil hardness test that was inspected by the Japan Paint Inspection Association.
2) Warpage A hot-air circulating oven was set at a temperature of 150 ° C. ± 10 ° C., heated for 30 minutes with the hard coat layer facing down, taken out, quenched at room temperature for 15 minutes, and then JIS B7 51 on a flat glass plate. Measurement was performed using No. 6 metal straight C-type first grade (15 cm length). The size of the measurement material is 8 cm × 5 cm.
Plus (+) warpage: Hard coat surface warps concavely.
Minus (-) Warp: Hard coat surface warps convexly.
3) Haze and total light transmittance Measured with a NDH-1001DP haze meter manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS K7105.
[0020]
【Example】
Hereinafter, the present invention will be described more specifically with reference to production examples of the transparent hard coat film used in the present invention and examples of the touch panel laminated with the transparent hard coat film .
[0021]
Production Examples 1-3
Polyethylene terephthalate having a reduced specific viscosity of 0.63 dl / g to which 70 ppm of silica having a particle size of 0.9 μm was added was dried and then melt-extruded at 290 ° C., 25 ° C. ( Production Examples 1 and 2) or 35 ° C. ( Production Example 3). The film was quenched and solidified using a casting drum set to 1 to obtain an unstretched film having a thickness of 1360 μm.
This unstretched film was stretched 3.25 times in the longitudinal direction at 85 ° C. using a roll stretching machine, and then stretched 3.35 times in the transverse direction at 95 ° C. using a tenter. Subsequently, it was heat-set at 215 ° C. to obtain a successively biaxially stretched polyester film having a thickness of 125 μm.
[0022]
The uncooled surface of the film was coated with a mixture of terephthalic acid, isophthalic acid and 5-sodium isophthalic acid (48 mol%, 47 mol% and 5 mol%, respectively), ethylene glycol and neopentyl glycol (40 mol% and 60 mol respectively). %) Was applied to the aqueous composition (water: isopropyl alcohol weight ratio = 85: 15) at a solid concentration of 5% by a roll coating method. It dried and formed the anchor coat film of 0.1 g / m < ² >.
[0023]
Next, an ultraviolet curable resin composed of a copolymer of acrylic acid, het acid anhydride, propylene oxide and xylylene diisocyanate is applied on the anchor coat film by a reverse roll coater, and then cured by ultraviolet rays. A 5 μm hard coat layer was formed.
[0024]
Furthermore, in Production Example 1, a thermosetting acrylic resin was applied to the back surface (non-coated surface) of the film on which the hard coat layer was formed with a gravure coater to form a 1 μm dry film.
The obtained transparent hard coat film was measured for pencil hardness, warpage, total light transmittance and haze.
[0025]
Production Example 4
In order to make the hard coat layer matt, a transparent hard hard disk is prepared in the same manner as in Production Examples 1 to 3 except that the amount of silica having a particle size of 0.9 μm added to the ultraviolet curable resin is 0.3% by weight. A coat film was obtained. For this film, the same measurement as in Production Examples 1 to 3 was performed.
The measurement results of Production Examples 1 to 4 are shown in Table-1.
[0026]
[Table 1]

[0027]
Production Examples 5-7
In Production Examples 2 to 4, a transparent hard coat was applied in the same manner as in these Examples, except that the non-cooled surface of the polyester film was subjected to anchor coating and UV curable resin hard coating on the cooled surface. -A film was obtained.
For this film, the same matters as in Production Examples 1 to 4 were measured. The results are shown in Table-2.
[0028]
[Table 2]

[0029]
Production Examples 8 to 11
An ultraviolet curable resin was applied to a sheet of 125 μm thick polycarbonate film ( Production Examples 8 and 9 ) and a polyester sulfone film ( Production Examples 10 and 11 ) using a wire bar, and then cured with ultraviolet light. Hard coat layers of 3 μ ( Production Examples 8 and 10 ) and 5 μ ( Production Examples 9 and 11 ) were formed.
This film was also measured for pencil hardness, warpage, total light transmittance and haze. The results are shown in Table-3.
[0030]
[Table 3]

[0031]
Examples 1 and 2
Using the transparent hard coat film of Production Example 1 and 3, apply the adhesive made of 25μ polyacrylate on the opposite side of the hard coat layer of this film, and overlay it on the surface of the touch panel to the pressure roll Further, after heating for 30 minutes at a temperature of 150 ° C., it was rapidly cooled to room temperature to produce a touch panel on which a hard coat film was laminated.
[0032]
Comparative Examples 1 and 2
Using the transparent hard coat film of Production Examples 5 and 6, this was laminated on the touch panel in the same manner as in Examples 1 and 2.
The state of the touch panel obtained in Examples 1 and 2 and Comparative Examples 1 and 2 was examined, and the results are shown in Table-4. In Table 4, “nearly none” refers to the case where it is not observed at all, or is not more than 5 per 10 cm × 10 cm.
[0033]
[Table 4]

[0034]
As is clear from Table-4, the touch panels obtained in Examples 1 and 2 and Comparative Examples 1 and 2 showed almost no cracks in the hard coat layer. In addition, in the touch panels of Examples 1 and 2, there was no bubble entrapment, film floating, or peeling. However, in the touch panels of Comparative Examples 1 and 2 , the film floated, peeled off, and some of the air bubbles were bitten, but this was solved by the choice of the transparent hard coat film to be used and the correction of the warp. It is.

Claims (1)

A hard-coated touch panel is formed by applying a transparent hard coat film on the surface of the touch panel after the touch panel is formed , applying an adhesive on the surface opposite to the hard coat layer, laminating them , pressing them, and then laminating them by heating. A hard coat with a pencil hardness of 2H or higher only on the surface on the non-cooled surface side when the transparent hard coat film is rapidly cooled and solidified using a casting drum of a transparent polyethylene terephthalate film as a substrate. A method for producing a hard-coated touch panel, wherein a layer is formed and the warpage of the film evaluated based on the following measurement method (A) is in the range of +5 mm to -10 mm.
(A) A hot-air circulating oven was set at a temperature of 150 ° C. ± 10 ° C., heated for 30 minutes with the hard coat layer facing down, taken out, quenched at room temperature for 15 minutes, and then JIS B7516 on a flat glass plate. Measuring method using a metal straight scale C-type first grade (15 cm length). The size of the measurement material is 8 cm × 5 cm.
Plus (+) warpage: Hard coat surface warps concavely.
Minus (-) Warp: Hard coat surface warps convexly.