JPH06180628A - Protecting film for touch inputting device - Google Patents

Abstract

PURPOSE:To improve the durability of the touch face of a touch inputting, device provided at the display face of a display by constituting the surface layer of a protecting film being a new touch face of an essentially transparent soft synthetic resin having its own recoverability and a friction resistance. CONSTITUTION:In the protecting file of thickness 0.1-2mm laminated on the touch face of the touch inputting device provided at the surface of the display of an input computer, the surface layer of the protecting film being the new touch face is constituted of the essentially transparent soft synthetic resin having its own recoverability and the friction resistance. As the soft synthetic resin of the surface layer being the touch face of the protecting film, a polyurethane resin is most preferable. It is necessary that the protecting film is constituted only of the specific synthetic resin, or equipped with a layer constituted of the material as one surface layer. It is necessary that the thickness of the protecting film is more than 0.1mm, and less than 2mm even when the protection film is equipped with an adhesive layer so that a sense of writing can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft synthetic resin protective film for protecting the touch surface of a touch input device which is excellent in writing feeling.

[0002]

2. Description of the Related Art In recent years, displays for computers and the like equipped with a transparent touch input device have been rapidly growing. This is because the touch input device provided on the display surface of the computer or the like inputs information with a pen or a finger. By doing so, the operation is simplified.

The display includes a CRT, a liquid crystal display element, a plasma display, and other displays, and the touch input device is provided on the front surface (display surface) of this display. Input to the touch input device is performed by turning on and off switches by resistance change and electrostatic capacitance change by a pen, a finger, etc. Usually, in this device, a large number of switches are arranged in a plane.

[0004]

Conventionally, the material constituting the touch surface of the touch input device is a hard plastic having fine irregularities for preventing reflection, a hard material such as glass, or a soft vinyl chloride resin. Soft materials have been used. However, when soft materials are used, they have a bad reputation such as slipperiness and hard feel at the time of input and are not well-received, and they have a drawback that they are easily scratched if they accidentally come into contact with sharp objects. It was On the other hand, when a soft material is used, the writing feeling is generally good, but it has a drawback that it is easily scratched by ordinary input and is inferior in durability.

[0005]

The present invention has been made to solve the above-mentioned problems, and is the following invention.

A protective film having a thickness of 0.1 to 2 mm laminated on the touch surface of a touch input device provided on the display surface of the display of the input computer, and the surface layer of the protective film serving as a new touch surface is A protective film which is essentially transparent and is made of a soft synthetic resin having self-healing property and scratch resistance.

Examples of the soft synthetic resin for the surface layer which is the touch surface of the protective film of the present invention include polyurethane resins, acrylic transparent rubber-like resins, silicone rubber-like resins, olefin-based and styrene-based elastomers, or both of them. Blended products with other resins, polymer alloys and the like can be used, but polyurethane resins are most preferable from the viewpoint of the balance of transparency, self-healing property and scratch resistance.

The protective film must be made of only this specific soft synthetic resin or have a layer made of that material as one surface layer. When this surface layer is laminated on the touch surface of the touch input device, it becomes a new touch surface. The protective film may further have one or more layers of synthetic resin, etc., and may particularly have an adhesive or pressure-sensitive adhesive layer. Further, the other layers may be partially present (for example, only in the peripheral portion). Preferably, the protective film of the present invention is made of only a specific soft synthetic resin, and when laminated on a touch input device, it is laminated using an adhesive, a pressure sensitive adhesive, a double-sided adhesive (or adhesive) tape, or the like. Moreover, when the surface itself of the protective film of the present invention has a certain degree of tackiness or adhesiveness, lamination can be performed only with the protective film.

The thickness of the protective film is required to be 0.1 mm or more from the viewpoint of improving the writing feeling, and it is not preferable that it is too thick for the recognition of input, and the protective film has an adhesive layer. Also, it is necessary to set it to 2 mm or less.
The thickness of the specific soft synthetic resin layer is 0.1 to 2 mm,
More preferably, it is 0.1 to 1.5 mm.

The surface of the specific soft synthetic resin layer (the surface to be the touch surface) may have fine irregularities called so-called embossing. This embossing is effective for antireflection. However, it is not preferable that the visible light transmittance of the protective film falls below 50% by providing this embossing. Furthermore, as long as it is essentially transparent, the protective sheet of the present invention may be colored or may be patterned by printing or the like. Further, a thin colored film or a patterned film may be laminated.

Hereinafter, the present invention will be described in the case where the protective film of the present invention is made of only a specific soft synthetic resin (hereinafter, simply referred to as soft synthetic resin), but the present invention is not limited to this.

The soft synthetic resin is essentially transparent (may be colored), and the visible light transmittance of the film is preferably 50% or more, particularly 80% or more. When the surface has fine irregularities, the transmittance of the film having it is preferably 50% or more.

The self-healing property means the property that scratches once generated disappear with time, and it is known that some soft synthetic resins have this property. The degree of the property can be measured, and the standard measurement method is Haydon (H
A method using an EIDON) scratch tester is known. Self-healing property of soft synthetic resin is 20 ℃, 50%
The self-healing property measured by a Haydon scratch tester with a diamond tip having a tip diameter of 15 μm as a damaged body in a relative humidity atmosphere is preferably 10 g or more, and particularly preferably 30 g or more.

Regarding the scratch resistance of the soft synthetic resin, the increase in the haze value after 100 rotations is less than 10% in the Daver abrasion test under a 500 g load using CS-10F as an abrasion wheel in the same atmosphere as described above. preferable.

The polyurethane resin is preferably a non-yellowing polyurethane resin from the viewpoint of durable yellowing. The yellow-free modified polyurethane-based resin refers to a polyurethane-based resin obtained from a non-aromatic or aromatic polyisocyanate having no isocyanate group directly bonded to an aromatic nucleus as a raw material.

As a molding method, an extrusion molding method, an injection molding method, a blow molding method, a casting method, a calender molding method, or the like can be used. Particularly, in view of the optical quality of the film which is related to the distortion of the image. Further, from the viewpoint that a crosslinkable resin can also be molded, a resin obtained by the reactive casting method is most preferable.

In the reactive casting method, a fluid reactive raw material mixture which reacts to form a soft synthetic resin is cast on a flat peelable carrier and reacted to form a thin layer of the soft synthetic resin. Then, the film or sheet is obtained by peeling from the carrier. When carrying out the reactive casting method, the reactive raw material may contain a solvent, but in the case of a polyurethane resin, a method using a reactive raw material containing substantially no solvent, that is, a reactive bulk casting method is more preferable. preferable.

The transparent, self-healing and scratch-resistant non-yellowing polyurethane resin obtained by the reactive casting method includes linear resin (thermoplastic resin) and cross-linking resin (thermosetting resin). Any of these is possible, but a crosslinkable resin is more preferable from the viewpoint of chemical resistance, stain resistance, durability and the like.

The cross-linkable polyurethane-based resin is a reactive main raw material composed of a polyfunctional active hydrogen compound (polyol or the like) and polyisocyanate, and at least one of the main raw materials and at least a part thereof is trifunctional or more. It is a polyurethane resin obtained by using a compound. On the other hand, all thermoplastic polyurethane-based resins are polyurethane-based resins obtained by using bifunctional raw materials.

The urethane-based resin obtained by the reactive casting method is a film obtained by casting a reactive raw material mixture obtained by mixing an active hydrogen compound such as a polyol and a chain extender and a polyisocyanate on a substrate and curing it. I will get it. As the polyol, polyether-based, polyester-based, polycarbonate-based, etc. can be used, but polyester-based polyols are preferable from the viewpoint of balance of durability, price, strength, scratch resistance and self-healing property. The number of functional groups is required to be larger than 1 as an average value, but it is preferably 2 to 3 from the viewpoint of the balance of strength, elongation, self-healing property and scratch resistance. If necessary, a chain extender can be used, and as the chain extender, a short chain polyol, a short chain polyamine or the like can be used. From the viewpoint of transparency and flexibility, short chain diols are preferable.

As the polyisocyanate, aromatic diisocyanate, aromatic polyisocyanate, aliphatic diisocyanate, aliphatic polyisocyanate, alicyclic diisocyanate, alicyclic polyisocyanate and the like can be used, but from the viewpoint of durable yellowing. Aliphatic or alicyclic diisocyanates or polyisocyanates are preferred.

These raw materials can be used alone or as a mixture. In addition, if necessary UV absorber
It is also possible to add stabilizers such as antioxidants and light stabilizers, urethanization catalysts, extenders, colorants, flame retardants and other additives.

Preferred crosslinkable polyurethane resins are polyols having an average hydroxyl value of 100 to 500, particularly 150 to 400, at least a part of which is trifunctional or more, and an average number of functional groups of 2.
It is a cross-linked polyurethane resin obtained by reacting the above non-yellowing polyisocyanate. The polyol is preferably triol alone (may be a mixture of two or more triols) or a mixture of triol and diol. The hydroxyl value of each polyol is not particularly limited, but the average hydroxyl value of all polyols is more preferably 200 to 400. This polyol may contain the above-mentioned chain extender which is a short-chain polyol, and the average hydroxyl value is the average hydroxyl value calculated including this.

The non-yellowing polyisocyanate is preferably an aliphatic or alicyclic polyisocyanate, more preferably trifunctional or higher functional polyisocyanate or a mixture thereof with a diisocyanate. As the tri- or higher functional polyisocyanate, diuretate-nurate modified buret modified and trimethylolpropane modified urethane modified with trihydric alcohol are preferable.

The present invention will be described below with reference to examples.
The present invention is not limited to these examples.

[0026]

【Example】

[Example 1]

[0027]

The mixture was stirred and mixed at 80 ° C. for 3 hours under heating and melting to prepare a uniform polyol system liquid.

In the above (and the same below),
"Parts" indicate parts by weight, and "" indicates the commercial product name.

Nurate-modified hexamethylene isocyanate having an NCO content of 21.4% 90.00 parts Isophorone diisocyanate 5.00 parts Hydrogenated MDI 5.00 parts Dibutyltin dilaurate 0.06 parts Stirring with heating at 80 ° C. for 3 hours To produce a uniform isocyanate system liquid.

These system liquids were continuously discharged and stirred and mixed at a weight ratio of polyol / isocyanate = 100 / 90.41, using a die, and continuously supplied with a release-treated smooth polyethylene terephthalate. A film (thickness: 0.1 mm) was uniformly coated with a film thickness of 0.3 mm and cast. This liquid film is placed in a continuous polymerization oven for 12
After heating at 0 ° C. for 20 minutes to essentially complete the polymerization,
It was wound with a base film. The base film and the product film were separated while paying out the obtained roll-shaped two-layer film to obtain a transparent protective film having self-healing property and scratch resistance. The performance and evaluation of the obtained film are shown in Table 1.

In Tables 1 and 2 below, protective films (Examples 1 to 8) produced in the following Examples, commercially available soft vinyl chloride resin films (referred to as "soft vinyl chloride"), and glass sheets (Comparative Examples 1 to 1) 2) shows performance and evaluation when the protective film of the present invention was used in place of it. The self-healing property and Taber abrasion are based on the above-mentioned evaluation method. The light transmittance, the tensile strength, and the tensile elongation are the evaluation results by the standard method (JIS). The writing feeling and the input recognizability are evaluation results when the protective film or the like of the present invention is laminated on a CRT with a touch input device (double-sided adhesive tape is used only in the peripheral portion except in Example 8) and information is input with a touch pen. , ○ and × 2
Shown in stages.

[Examples 2 to 6] Polyol system liquids having the following compositions were prepared by the same method as in Example 1,
An isocyanate system liquid was produced and a transparent protective film having self-repairing property and scratch resistance was obtained by a continuous casting method. The film thickness and film performance are shown in Table 1. For all compositions, 0.3% by weight of extender ("BYK-300"), 0.2% by weight of light stabilizer ("MARKLA-7H"), 0.2% by weight Antioxidant ("IRGANOX1010"), 0.3% by weight of UV absorber ("TINUVIN328") in the polyol system liquid, and 30% to the total of both system liquids.
ppm of urethanization catalyst (dibutyltin dilaurate) was blended into the isocyanate system liquid.

[Example 2] Polycaprolactone triol having a hydroxyl value of 196.4 40.66 parts Polycaprolactone triol having a hydroxyl value of 540.3 11.62 parts Polycaprolactone diol having a hydroxyl value of 37.6 5.81 parts NCO content 21 4% Nurate-modified hexamethylene isocyanate 37.73 parts Isophorone diisocyanate 2.10 parts Hydrogenated MDI 2.10 parts

[Example 3] Polycaprolactone triol having a hydroxyl value of 196.4 14.14 parts Polycaprolactone triol having a hydroxyl value of 540.3 28.28 parts Polycaprolactone diol having a hydroxyl value of 37.6 4.71 parts NCO content 21 4% Nurate-modified hexamethylene isocyanate 47.58 parts Isophorone diisocyanate 2.64 parts Hydrogenated MDI 2.64 parts

[Example 4] Polycaprolactone triol having a hydroxyl value of 196.4 45.14 parts 1,4-butanediol 9.03 parts Nurate-modified hexamethylene isocyanate having an NCO content of 21.4% 25.20 parts Isophorone diisocyanate 20 .62 parts

[Example 5] Polycaprolactone triol having a hydroxyl value of 196.4 49.91 parts 1,4-butanediol 5.00 parts Nurate-modified hexamethylene isocyanate having an NCO content of 21.4% 40.59 parts Isophorone diisocyanate 4 .51 copies

Example 6 Poly (oxypropylene) triol having a hydroxyl value of 397.0 50.00 parts Biuret-modified hexamethylene diisocyanate having a hydroxyl value of 20.3 50.00 parts

[Example 7] Using the same raw material mixture as in Example 1, a polyethylene terephthalate film (thickness: 0.05 mm) was embossed and then treated with a release agent.
The same reaction casting method as above was performed to obtain a transparent, self-repairing, and scratch-resistant antireflection protective film.

[Embodiment 8] Using the same raw material mixture as in Embodiment 1, a polyethylene terephthalate film (thickness: 0.05, which is embossed on the surface and then treated with a release agent) is used.
mm) was subjected to the same reaction casting method to obtain a transparent, self-repairing, and scratch-resistant antireflection protective film.

An acrylic pressure-sensitive adhesive was applied as a solution on the smooth surface of this film, and the solution was dried and laminated with a low-density polyethylene film (thickness 0.01 mm) as a release film. The obtained film could be easily adhered to the display after peeling the release film.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

The protective film of the present invention is excellent in self-healing property and scratch resistance, and has a good writing feeling on the touch surface. In addition, the protective film is not only excellent in light transmittance and other physical properties, but also has little deterioration in input recognition.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor St. Kuriyama 2-1-2 Marunouchi, Chiyoda-ku, Tokyo Asahi Glass Co., Ltd.

Claims (6)

[Claims] 1. A protective film having a thickness of 0.1 to 2 mm laminated on a touch surface of a touch input device provided on a display surface of a display, and the surface layer of the protective film serving as a new touch surface is essential. A protective film that is made of a soft synthetic resin that is transparent and has self-healing property and scratch resistance. 2. The visible light transmittance of the protective film is 50% or more, and the tip diameter is 1 at 23 ° C. and 50% relative humidity.
The self-healing property of the soft synthetic resin measured with a HEIDON scratch tester with a 5 micron diamond tip as a scratch body is 10 g or more, and CS-10F is used as a wear wheel under the same atmosphere, and Taber wear under a load of 500 g. The protective film according to claim 1, wherein the haze value of the soft synthetic resin after 100 rotations in the test is less than 10%. 3. The protective film according to claim 1, wherein the soft synthetic resin is a non-yellowing polyurethane resin. 4. The protective film according to claim 1, which has fine irregularities for antireflection on the touch surface side of the protective film. 5. A non-yellowing polyurethane-based soft synthetic resin film having a thickness of 0.1 to 2 mm, which is obtained by forming a reactive raw material mixture into a film by a reactive casting method to form a soft synthetic resin as a protective film. And claim 1
Film. 6. A crosslinkable polyurethane resin film obtained by using a reactive raw material containing a trifunctional or higher functional polyol and / or a trifunctional or higher functional polyisocyanate as the yellow-free modified soft polyurethane resin film. 5
Protective film.