JPH0754647B2 - Multilayer film for touch switch - Google Patents

Description

The present invention relates to a laminated film for a touch switch, and more particularly to a laminated film for a touch switch formed by laminating a wear resistant layer having a surface electric resistance of 10 ¹² Ω / port or less. Is.

[Prior Art] Conventionally, a laminate of a polyester film / a conductive layer is known as a laminate film for a touch switch. Further, the polyester film is easily scratched, and in order to prevent it, a laminate of abrasion resistant layer / polyester film / conductive layer is also known (JP-A-56-55253, JP-A-60-1).
31238).

However, such a conventional laminate for a touch switch has a high surface resistance such as 10 ¹⁴ to 10 ¹⁷ Ω / mouth of the surface polyester film or abrasion resistant layer of the laminate, so that static electricity is generated by tentacles and friction. Since the static electricity is generated and stored, the static electricity causes the switch to remain input, resulting in poor operability.

[Problems to be Solved by the Invention] The object of the present invention is to eliminate the above-mentioned drawbacks, to generate static electricity,
An object of the present invention is to provide a laminated film for a touch switch, which is free from electric charge and does not cause poor operability.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following constitution, namely, an organic polymer film substrate A having a surface electric resistance of 10 ¹² Ω / port or less and a quaternary ammonium salt. Abrasion resistant layer B formed of a layer composed of a mixture of a salt copolymer and a melamine compound and a layer composed of an organosilicon compound, and a surface electric resistance of 3 × 10 ³
Ω / port or less of transparent conductive layer C is laminated in the order of A / B / C,
The laminate has a light transmittance of 70% or more, or a laminated film for a touch switch, or an organic polymer film substrate A, which has a surface electric resistance of 10 ¹² Ω / port or less and an organosilicon film. A wear resistant layer B made of a mixture of a compound and tin oxide and a transparent conductive layer C having a surface electric resistance of 3 × 10 ³ Ω / port or less are laminated in the order of B / A / C, and the light transmittance of the laminate is It is intended to provide a laminated film for a touch switch, which is 70% or more.

The organic polymer film substrate A constituting the laminate of the present invention is preferably a polymer film made of a well-known thermoplastic resin and having excellent mechanical strength and dimensional stability and high transparency, and stretched polyethylene. A terephthalate film is most suitable, but a film made of polycarbonate, polypropylene or the like is also suitable. The organic polymer film substrate A may be subjected to a known surface treatment such as corona discharge treatment or provided with a surface modification layer in order to improve the adhesiveness if necessary. The thickness of the film is usually 50
~ 250μ can be used, but 100 ~ 200μ is preferable from the strength of the waist as a touch switch.

The surface electrical resistivity 10 ¹² Omega / mouth following wear-resistant layer B constituting the laminate of the present invention, the surface electrical resistance 10 ¹² Omega / mouth for holding the following material and for holding the wear-resistant A layered or mixed material is used.

Organosilicon compounds (hereinafter referred to as “silicon compounds”) are suitable as materials that maintain wear resistance, and these are R ¹ _n SiX _m (where R ¹ is a form in which carbon is directly bonded to silicon). Methyl, phenyl, γ-methacryloxypropyl, γ
-Glycidoxypropyl, N (β-aminoethyl) γ-
An organic group such as aminopropyl, γ-methylcaptopropyl and vinyl, preferably having 1 to 7 carbon atoms, and X is C ₁
To C ₆ alkoxy group, n is 0 or 1, m is 3 or 4
Integer. ), For example, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, N (β-aminoethyl) γ- Aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltriethoxysilane, etc. are hydrolyzed to give a prepolymer by hydrolyzing the alkoxy group with a dilute acidic aqueous solution such as dilute hydrochloric acid aqueous solution or dilute sulfuric acid aqueous solution. It is a cured product of the paint obtained by mixing with the components. The cured product has a Si-O-Si group, which is a condensate of -SiOH groups contained in a hydrolyzed prepolymer of a silicon compound, and has a maximum absorption at a wavelength of 8 to 10 µ in its infrared absorption spectrum.

Since the silicon compound layer is a condensation reaction cured product as described above, curling easily occurs due to shrinkage of the coating film, but in the general formula R ¹ _n SiX _m , R ¹ is an organic group containing a glycidoxy group. In this case, curling is small, flexibility is excellent, and no crack occurs in the coating film even at 10% elongation, which is preferable.

The thickness of the silicon compound layer is preferably 0.5-10 μm, more preferably 2-6 μm. If the film thickness is less than 0.5 μ, abrasion resistance is insufficient and scratches are likely to occur. On the other hand, if the film thickness exceeds 10 μ, cracks are likely to occur in the coating film, which is not preferable.

Surface electric resistance of silicon compound layer is 10 ¹⁴ Ω / 10 ¹⁷ Ω /
The surface electrical resistance of the silicon compound layer is 10 ¹² Ω
In order to keep the temperature below the mouth, the resistance layer and the silicon compound are laminated, or the silicon compound and the conductive powder are mixed and used.

As the low resistance layer, a cured product layer composed of a quaternary ammonium salt copolymer and a melan compound is preferable because it has excellent adhesion to the film substrate and the silicon compound. Fourth
The mixing ratio of the quaternary ammonium salt copolymer and the melamine compound is 3 to 40 for the former 100 parts by weight based on the solid content weight ratio.
It is preferably in the range of parts by weight.

If the amount of the melamine compound is less than 3 parts by weight, the curing will be insufficient and the silicon compound to be overcoated or the solvent thereof will not be able to exhibit conductivity. On the other hand, if the amount exceeds 40 parts by weight, the content of the conductive polymer decreases, and the conductivity cannot be exhibited.

The quaternary ammonium salt copolymer is a conductive polymer having at least one quaternary ammonium salt in a repeating unit and has a general formula (Wherein R ² is hydrogen or a methyl group, and R ³ is a methyl group or an ethyl group) and a quaternary ammonium compound A represented by the general formula (In the formula, R ⁴ is hydrogen or a methyl group, R ⁵ is a methyl group or an ethyl group.) A copolymer of a quaternary ammonium compound B having a copolymerization ratio of A of 100 to 60 mol%, B
Is preferably 0 to 40 mol%. If B exceeds 40 mol%, the curing reaction with the melamine compound may become insufficient,
When overcoated, there are cases in which the silicon compound or its solvent may not be able to exert conductivity due to being attacked.

As the quaternary ammonium A, for example, 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride, 2-hydroxy-3-acryloxypropyltriethylammonium chloride, and as the quaternary ammonium salt B, for example, 2-methacryloxyethyltrimethyl. Ammonium chloride, 2-acryloxytriethylammonium chloride and the like can be used.

The melamine compound is a methylolated melamine or an alkyl etherified methylol melamine represented by the following general formula.

(Wherein, R ^6, R ⁷ is _{-H, -CH 2 OH, -CH 2} -OR 8 (R 8 is C
A group selected from _{1 to} C ₄ alkyl groups). R ⁶ and R ⁷ may be the same or different. ) The thickness of the cured product layer comprising the quaternary ammonium salt copolymer and the melamine compound is preferably 0.1 to 5 μ, more preferably 0.2 to 2 μ.

Zinc oxide as the conductive powder to be mixed with the silicon compound,
Examples thereof include tin oxide, and more preferable is tin oxide doped with antimony.

The mixing ratio of the silicon compound and tin oxide is preferably 50 to 600 parts by weight with respect to the solid content of 100 parts by weight of the former,
It is more preferably 100 to 400 parts by weight. If the latter is less than 50 parts by weight, the antistatic property is insufficient, and if it exceeds 600 parts by weight, the wear resistance is deteriorated.

Since the tin oxide-containing silicon compound forms fine irregularities on the surface of the coating film, as a result, a matte effect is exhibited and reflection on the coated surface can be prevented.

Silicon dioxide is effective as a mixed powder for the purpose of imparting a matt to the silicon compound layer.
The silicon dioxide powder has an average particle size of 0.1 to 10μ, and is 3 to 5 per 100 parts by weight of the solid content of the silicon compound.
A matting effect can be exhibited by mixing at a ratio of 0 part by weight.

As the transparent conductive layer C having a surface electric resistance of 3 × 10 ³ Ω / port or less, which constitutes the laminate of the present invention, at least one of conductive layers such as a metal compound containing 50% or more of gold or silver or indium tin oxide is used. A thin film of seeds is preferred and its thickness is
10 to 1000Å is suitable. The composition of indium / tin oxide is preferably 85 to 95% by weight of indium oxide (In ₂ O ₃ ) and 15 to 5% by weight of tin oxide (S _n O ₂ ). On the other hand, the metal compound containing gold and silver may be used alone, but a gold-silver alloy is preferable in terms of transparency and corrosion resistance, and a gold content of 30 to 70% is preferable.

Next, a method for producing the laminated film of the present invention will be described.

First, the organic polymer film substrate A can be produced by heating and melting polyethylene terephthalate, polycarbonate, polypropylene resin and the like by a known method to form a sheet, and then stretching the sheet if necessary. In order to produce a highly transparent film, it is necessary to keep the cooling temperature at the time of melt molding low and to prevent the inclusion of foreign matter in order to improve the smoothness of the surface.

Next, the wear resistance layer having a surface electric resistance of 10 ¹² Ω / mouth or less was prepared by dissolving the quaternary ammonium salt copolymer and the melamine compound in a solvent to adjust the concentration to 1 to 10%, and a curing catalyst was added if necessary. After coating the coating on one side of the organic polymer film with a normal roll coater, spray method, etc. and heating and curing,
On the surface of the coating film, R ¹ _n SiX _m (wherein R ¹ is an organic group in which carbon is directly bonded to silicon, X is a C _{1 to} C ₆ alkoxy group, n is 0 or 1, m is an integer of 4 or 3.) A dilute acidic aqueous solution, for example, a dilute hydrochloric acid aqueous solution of N / 1000 to N / 10 is added to the compound to hydrolyze it into a prepolymer, and then a curing agent if necessary. , A curing catalyst, additives, etc., and further diluted with a solvent to adjust the concentration to 5-40%, and then apply it by a roll coater, spray method, etc., and heat it, or irradiate it with ultraviolet rays, β rays, γ rays. To cure.

The coating film can be made matte by mixing silicon dioxide particles with the above-mentioned coating material containing the hydrolyzed prepolymer as a main component.

In addition, when tin oxide is mixed with a paint containing a hydrolyzed prepolymer as a main component, the paint alone can exhibit abrasion resistance and antistatic property, and in this case, it can be directly applied to the organic polymer film.

Next, the transparent conductive layer C is formed by applying 50% of indium tin oxide or gold or silver on the non-coated surface of the above coated laminated film.
The metal compound containing the above is formed into a thin film by a method such as electron beam evaporation or sputtering. Surface electric resistance is 3 × 10 ³ Ω
In order to keep the thickness below / hole, the thickness of the deposited film is at least 30Å or more for indium tin oxide, preferably 50 to 30
0Å, 50 for metal compounds containing 50% or more of gold or silver
It is recommended to set it up to 300Å.

Abrasion resistant layer B containing the organosilicon compound of the present invention
Has significantly better wear resistance than a wear resistant layer made of an inorganic silicon compound such as silicon oxide. Since the layer of silicon oxide cannot heat the organic polymer film substrate A, only a powdery substance is attached and the film itself has no strength. On the other hand, the organic silicon compound has a uniform and integrated film formed without requiring significant heating, and has much higher abrasion resistance than the silicon oxide layer.

The characteristic value of the present invention is measured by the following measuring method.

(1) Abrasion resistance Wear-resistant layer (B
Rub the layer) 10 times and visually check for scratches on the rubbed portion.

(2) Surface electric resistance value A sample cut into a width of 35 mm is placed on a rubber sheet having a rubber hardness of about 60 degrees. Two 2mm thick palladium plates spaced 3
The measurement electrode set to 5 mm was placed at a position orthogonal to the sample, a load of 500 g was applied, and the resistance value between the electrodes was directly read using a digital tester (VOAC707 manufactured by Iwasaki Tsushinki).

(3) Switch operability After rubbing the surface of the touch switch with a nylon cloth 10 times, immediately operate the switch to check for any switch malfunction. This evaluation is repeated 10 times.

(4) Light transmittance Measured according to JIS K6714-58.

(5) 60 degree specular gloss The degree of matte is expressed in terms of gloss. The smaller the value of glossiness, the stronger the degree of matting. The glossiness was measured according to JIS K5400-79.

[Examples] Next, embodiments of the present invention will be described based on Examples.

Example 1 The following coating AC was applied to one side of a biaxially stretched polyethylene terephthalate film (thickness 100 μ) at a solid content of 1
Apply with a roll coater to g / m ² and apply at 140 ℃ for 5
Dry for minutes. Subsequently, the following paint TC-1 was applied on the coating surface.
Was coated with a roll coater so that the solid coating amount was 4 g / m ^2, and dried at 150 ° C. for 3 minutes to obtain a coated laminated film. 1 _{n 2} O ₃ / S _n O on the non-coated surface of the obtained coated laminated film
₂ , 90/10 thin film of indium tin oxide was formed into a thin film with a thickness of 200Å by a sputtering method to obtain a laminated film for a touch switch. The degree of vacuum is 10 for sputtering.
^It was carried out at ^-3 Torr with the introduction of argon gas. The transparent conductive surface of the thus obtained laminated film for a touch switch was chemically etched to form a circuit. In other words, Nikkei Electronics June 8, 1981, 122
As described on page 137, strip-shaped transparent electrodes were placed opposite to each other to form a switch matrix which was combined vertically and horizontally. Details are as in the literature.

After the circuit was created, the switch was assembled by facing the counter electrode through the spacer. Table 1 shows the evaluation results of this switch.

Paint AC quaternary ammonium salt copolymer The former is a copolymer of 80 mol% and the latter is 20 mol% and is an aqueous solution with a concentration of 30%. ) 100 parts by weight and 13 parts by weight of a melamine compound (“Nikalac” MW12-LF manufactured by Sanwa Chemical Co., Ltd., concentration 70%) are dissolved in 280 parts by weight of a solvent of water / methanol = 1/1 (weight ratio). I prepared it.

Paint TC-1 γ-glycidoxypropyltrimethoxysilane N / 100
-Paint prepared by dissolving 100 parts by weight of a prepolymer (solid content concentration 58%) obtained by hydrolysis with an aqueous hydrochloric acid solution in 210 parts by weight of toluene, and then adding and dissolving 6 parts by weight of acetylacetone aluminum salt as a curing agent. TC-1 was obtained.

Comparative Example 1 In Example 1, the application of the coating AC was omitted, the coating TC-1 was directly applied to the polyethylene terephthalate film, and then an indium tin oxide thin film was formed in the same manner as in Example 1 to prepare a circuit. I assembled the touch switch. The evaluation results are shown in Table 1.

Example 2 On one side of a biaxially stretched poly (ethylene terephthalate) film (thickness 188 μ), the paint TC-1 of Example 1 and tin oxide (ELCOM, TL-20 manufactured by Catalysts & Chemicals Industries Co., Ltd.) were added as solid weight. The ratio of 100/100 mixed and dispersed paint is 5
Apply with a roll coater to g / m ² and apply at 150 ℃ for 3
After drying for a minute, a coated laminated film was obtained. The thickness of the non-coated surface of the obtained coated laminated film was 100 by sputtering.
A thin film of gold of Å was formed to obtain a laminated film for a touch switch. The laminated film was formed into a circuit and made into a switch in the same manner as in Example 1. Table 1 shows the evaluation results of this switch.

Example 3 The coating AC of Example 1 was coated on one side of a biaxially stretched polyethylene terephthalate film (thickness 125 μ) with a roll coater so that the solid coating amount was 2 g / m ² , and the temperature was 140 ° C.
And dried for 10 minutes. Subsequently, the paint TC-1 of Example 1 and silicon dioxide ("Syloid" 150 manufactured by Fuji Davisson Co., Ltd., average particle size 2.5 µ) were applied to the surface of the coating film at a solid content weight ratio of 100.
A coating material mixed / dispersed in 100/100 was applied with a roll coater so that the solid coating amount was 5 g / m ² and dried at 150 ° C. for 3 minutes, and then a thin film of indium tin oxide was prepared as in Example 1. Formed, created circuits, made into switches. The evaluation results are shown in Table 1.

Comparative Example 2 In the same manner as in Example 1, the coating AC and the coating TC-1 were not applied, but only the light-conducting conductive film was formed, and a switch was formed in the same manner. The evaluation results are shown in Table 1.

Comparative Example 3 Palladium was formed to a thickness of 150 Å in place of indium tin oxide in Example 1. In this case, as shown in Table 1, there was no problem in the function as a switch, but the light transmittance was significantly lowered.

Claims (4)

[Claims] 1. An organic polymer film substrate A comprising a layer having a surface electric resistance of 10 ¹² Ω / port or less and comprising a mixture of a quaternary ammonium salt copolymer and a melamine compound, and an organosilicon compound. A wear-resistant layer B formed of layers and a transparent conductive layer C having a surface electric resistance of 3 × 10 ³ Ω / port or less are laminated in the order of B / A / C, and the light transmittance of the laminate is 70% or more. A laminated film for a touch switch, which is characterized. 2. The transparent conductive layer C having a surface electric resistance of 3 × 10 ³ Ω / port or less is made of indium tin oxide or gold or silver.
The laminated film for a touch switch according to claim (1), which is a metal compound containing 50% or more. 3. An organic polymer film substrate A having a surface electric resistance of 10 ¹² Ω / port or less, a wear resistant layer B made of a mixture of an organic silicon compound and tin oxide, and a surface electric resistance of 3 × 10 5.
A transparent conductive layer C of ³ Ω / port or less is laminated in the order of B / A / C,
A laminated film for a touch switch, wherein the laminated body has a light transmittance of 70% or more. 4. The transparent conductive layer C having a surface electric resistance of 3 × 10 ³ Ω / port or less is made of indium tin oxide or gold or silver.
The laminated film for a touch switch according to claim (3), which is a metal compound containing 50% or more.