JPH09111020A - Hard coat film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a hard coat film capable of presenting stable antimicrobial performance while retaining its unique performance such as scratch resistance and wear resistance, etc., by forming a specific antimicrobial curable resin layer on a plastic film. SOLUTION: This hard coat film is obtained by providing one or both sides of a plastic film (pref. biaxially oriented film) with antimicrobial curable resin layer(s) 0.1-3μm in Ra value determined by the JIS B-0601 and >=H grade in pencil hardness determined by the JIS K-5400. The curable resin layer is pref. obtained from (A) a photopolymerizable prepolymer (pref. an acryloyl-contg. acrylic prepolymer such as urethane acrylate), (B) a photopolymerizable monomer (e.g. 2-ethylhexyl acrylate), (C) a photopolymerization initiator (e.g. a diazonium salt), and (D) an antimicrobial agent (pref. silver ion).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial hard coat film, and more particularly to a surface substrate such as a membrane switch, a flat panel display, a display screen that can be seen through or a pen input type touch panel. The present invention relates to a hard coat film having suitable antibacterial properties.

[0002]

2. Description of the Related Art In recent years, membrane switches have been used in operation panels of various devices. When operating such a membrane switch, if bacteria or the like propagate on the surface of the membrane switch, there is a high possibility that it will be infected with a disease. In particular, there is a high possibility that bacteria will adhere to the operation panel of a home shower / toilet, a microwave oven, a washing machine, and the like, and an environment in which bacteria are likely to propagate, such as an appropriate temperature and humidity, is often prepared.

Further, the membrane switch is used in many devices such as a copying machine and an air conditioner switch which are operated by an unspecified number of people, and in such a device, there is a high possibility that bacteria will adhere. .

Furthermore, recently, nosocomial infections in which bacteria such as MRSA (methicillin-resistant Staphylococcus aureus) are infected in hospitals have become a problem. In order to prevent the infection of such bacteria, it is necessary to prevent the propagation of bacteria on the operation panel.

On the other hand, in the conventional antibacterial film, since the resin is uniformly mixed with the antibacterial agent and formed into a film (Actual Kaihei No. 7-9952), stable antibacterial performance is exhibited. I couldn't.

In particular, when such an antibacterial film is used for applications such as a membrane switch used by a large number of unspecified persons in various modes, it is very easy because of its lack of scratch resistance and abrasion resistance. However, there is a drawback in that the surface of a switch or the like is significantly impaired by scratches on the surface.

[0007]

SUMMARY OF THE INVENTION Therefore, the present invention provides a hard coat film capable of exhibiting more stable antibacterial performance while maintaining the performance as a so-called hard coat material such as scratch resistance and abrasion resistance. With the goal.

[0008]

The hard coat film of the present invention has Ra of 0.1 to 3.0 in JIS-B0601 on one side or both sides of a plastic film.
It is characterized by having a curable resin layer having an antibacterial property and having a pencil hardness of H or more according to JIS-K5400.

In particular, it is desirable that the curable resin layer is a layer formed of at least a photopolymerizable prepolymer, a photopolymerizable monomer, a photopolymerization initiator and an antibacterial agent.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The hard coat film of the present invention will be described in detail below.

Any plastic film can be used as long as it has a function as a support, and examples thereof include a film or sheet made of polyethylene terephthalate, polybutylene terephthalate, polycarbonate, acryl, triacetate or the like. Among these, stretching processing, particularly biaxially stretching, is preferable because mechanical strength and dimensional stability are improved. The thickness can be appropriately selected depending on the applied material, but is generally 25 to 250 μm.

The curable resin layer formed on one side or both sides of the plastic film has a scratch resistance,
It has a role of imparting antibacterial properties.

The curable resin layer having such an antibacterial property is formed by an antibacterial agent containing a polymer binder mainly composed of a thermosetting resin or an ionizing radiation curable resin and an antibacterial metal ion.

In particular, in the present invention, R on the surface of the curable resin layer containing an antibacterial agent for effectively exhibiting antibacterial performance.
a is adjusted within a certain range. This will be described later.

As the thermosetting resin, resins such as organopolysiloxane resins, melamine resins and polyurethane resins can be used. Particularly, ionizing radiation curable resins are used from the viewpoints of work environment and productivity. preferable.

The ionizing radiation curable resin is formed from a coating material containing at least a resin which is cured by irradiation with electron beams or ultraviolet rays. Specifically, it contains a photopolymerizable prepolymer, a photopolymerizable monomer, a photopolymerization initiator, and further contains a sensitizer, a non-reactive resin, an additive such as a leveling agent, and a solvent, if necessary. Is.

The photopolymerizable prepolymer has its structure and molecular weight related to the curing of the ionizing radiation curable coating material, and defines the properties such as the adhesiveness, hardness and crack resistance of the ionizing radiation curable resin. The photopolymerizable prepolymer undergoes radical polymerization when the acryloyl group introduced into the skeleton is irradiated with ionizing radiation. Those that cure by radical polymerization have a fast curing speed and a large degree of freedom in resin design.
Particularly preferred.

As the photopolymerizable prepolymer, an acrylic prepolymer having an acryloyl group is particularly preferable, which has two or more acryloyl groups in one molecule and has a three-dimensional network structure. As the acrylic prepolymer, urethane acrylate, epoxy acrylate, melamine acrylate, polyester acrylate and the like can be used.

The photopolymerizable monomer is used for diluting the high-viscosity photopolymerizable prepolymer, lowering the viscosity, improving workability, and imparting coating strength as a crosslinking agent. .

As the photopolymerizable monomer, monofunctional acrylic monomers such as 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, butoxyethyl acrylate, 1,6
-Bifunctional acrylic monomers such as hexadiol acrylate, neopentyl glycol diacrylate, hydroxypavirin ester neopentyl glycol acrylate, dipentaerythritol hexaacrylate,
One or more of polyfunctional acrylic monomers such as trimethylpropane triacrylate and pentaerythritol triacrylate are used.

Further, since the coating film becomes harder than necessary when the amount of the photopolymerizable monomer mixed is increased, the mixing ratio may be appropriately selected so as to obtain a desired hardness or a desired flexibility. For example, when the hard coat film of the present invention is used for a bent portion, it has excellent flexibility and thermosetting property,
The hardness can be adjusted by mixing a non-reactive resin such as a thermoplastic acrylic resin or an epoxy resin.

The photopolymerization initiator is added in order to start the reaction of the acryloyl group by irradiation of ionizing radiation in a short time and accelerate the reaction, and has a catalytic action. The photopolymerization initiator is required particularly when curing is performed by ultraviolet irradiation, and may not be required when irradiating a high energy electron beam. As the kind of the photopolymerization initiator, there are radical polymerization by cleavage, radical polymerization by abstracting hydrogen, and cationic polymerization by generating ions.

Examples of the photopolymerization initiator include radical-type photopolymerization initiators such as benzoin ether type, ketal type, acetophenone type and thioxanthone type, diazonium salts, diaryl iodonium salts, triaryl sulfonium salts and complex type cations. Examples of the photopolymerization initiator include one type or two or more types thereof. The photopolymerization initiator is used in a mixture of 2 to 10% by weight, preferably 3 to 6% by weight, based on the resin solid content.

To cure the ionizing radiation curable paint,
Irradiate with electron beam or ultraviolet ray.

When irradiating with an electron beam, a scanning or curtain type electron beam accelerator is used, and an accelerating voltage of 1000 ke
It can be performed by irradiating with an electron beam having an energy of V or less, preferably 100 to 300 keV and having a wavelength region of 100 nm or less.

When irradiating with ultraviolet rays, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a metal halide lamp or the like is used, and the wavelength is 100 to 400 nm, preferably 2 nm.
50 to 300 kcal in the wavelength region of 00 to 400 nm
Irradiate with ultraviolet light having an energy of / mol.

Antibacterial agents used in the present invention include gold, silver,
Zeolite-based solid particles carrying at least one metal ion such as copper, zinc, lead, platinum, antimony, nickel, aluminum, cadmium, manganese, or solid particles carrying a metal complex coordinated with these metal ions, etc. Is mentioned. Zeolite containing silver ion or silver complex salt is particularly preferable in consideration of safety to human body.

The shape of the antibacterial agent is preferably a particulate shape, particularly a spherical shape. This is to impart uniform surface irregularities to the surface of the curable resin layer.

In the present invention, it is necessary that the surface roughness of the curable resin layer containing the antibacterial agent is controlled. That is, Ra in JIS-B0601 of the curable resin layer is in the range of 0.1 to 3.0 μm, preferably 0.3.
To 1.5 μm, more preferably 0.5 to 1.
The range of 0 μm is preferable.

By thus setting Ra within a certain range, the antibacterial agent can be projected onto the surface of the curable resin layer to the extent that the antibacterial performance can be effectively exhibited.

If the Ra is extremely small, in other words, if it is less than 0.1 μm, the antibacterial agent is completely buried in the curable resin layer and the antibacterial effect cannot be exerted. When Ra is too large, in other words, when it exceeds 3.0 μm, the ratio of the antibacterial agent jumping out from the surface of the curable resin layer increases, and the antibacterial agent is easily chipped off due to a slight friction or the like. This is because the hard coat performance that is sufficient, that is, H or higher cannot be obtained with the pencil hardness described below. In particular, by adjusting Ra in the range of 0.5 to 1.0 μm, it is possible to obtain a transparent curable resin layer that can be used in a transparent touch panel or the like.

The average particle size of the antibacterial agent is 0.1 to 50 μm,
It is preferably 1 to 20 μm. 0.1μ
If it is less than m, the antibacterial agent will be buried in the coating film and the antibacterial effect cannot be exhibited. On the other hand, if it exceeds 50 μm, the proportion of the antibacterial agent in the coating film will increase and the hardness will decrease.

The amount of the antibacterial agent added is based on the total weight of the resin.
0.1 to 30% by weight, preferably 2 to 20% by weight
Range. If it is less than 0.1% by weight, the antibacterial agent in the resin coating film becomes too sparse and sufficient antibacterial performance cannot be obtained.
This is because if it exceeds 30% by weight, the proportion of the antibacterial agent in the resin coating film increases, and the performance such as scratch resistance and abrasion resistance deteriorates.

In order to obtain the so-called hard coat material performance such as scratch resistance and abrasion resistance, the hardness of the curable resin layer must be at least H or more, preferably 2H or more in terms of pencil hardness according to JIS-K5400. Is.
2H from the viewpoint of scratch resistance, wear resistance, and bendability
~ 5H is more preferred. If the Ra exceeds 3.0 μm, the pencil hardness of the resin layer becomes less than H, scratches are likely to occur, and the surface appearance when used as a surface base material is significantly impaired.

In order to form a curable resin layer having such a composition, when an ionizing radiation curable resin is used, an ionizing radiation curable resin coating material containing an antibacterial agent is applied to a plastic film, and an electron beam or an ultraviolet ray is applied. Is formed by irradiation.

The ionizing radiation curable coating composition can be applied to the plastic film by a conventional coating method such as a bar, blade, gravure, spin or spray coating method.

When the ionizing radiation-curable coating material is cured by irradiating it with an electron beam or an ultraviolet ray, the presence of oxygen and the thickness of the coating film are closely related to the curing. Radicals generated by irradiation with ionizing radiation supplement oxygen, thereby suppressing curing. Therefore, when the thickness of the coating film is small, the surface area occupying the volume of the coating film becomes large, and the coating is easily affected by curing in air. Further, when the coating film is thick, it is difficult for ionizing radiation to penetrate to the inside, and even if the surface is hardened, internal hardening is not sufficient and the uncured portion of the coating interface exists, so the curable resin layer Will cause poor adhesion with the plastic film. In order to prevent such curing inhibition and uncuring, particularly in the case of electron beam irradiation, irradiation can be performed under an inert gas such as N ₂ gas. Further, the inhibition of curing can be prevented by adjusting the thickness of the coating film, selecting a photopolymerizable prepolymer or a photopolymerizable monomer having a fast curing rate, and increasing the mixing amount of the photopolymerization initiator.

[0038]

The present invention will be described in more detail with reference to the following examples. In addition, "part" and "%" are based on weight unless otherwise specified. Ra represents the center line average surface roughness.

[Example 1] On a 125 μm thick polyester film, a curable resin layer coating solution having the following composition was applied with a Meyer bar and sufficiently cured at 150 ° C., according to JIS-B0601. Ra is 0.5 μm
Then, a hard coat film having a curable resin layer having a thickness of 4 μm was obtained.

-Organopolysiloxane resin 77.2 parts (Si coat A2: Daihachi Chemical Industry Co., Ltd.)-Antibacterial agent 1.8 parts (Zeomic AW10D, particle size 2 μm: Sinanen Co.)-Methyl ethyl ketone 21.0 parts

[Example 2] Zeomic AW1 of Example 1
JIS-B0 in the same manner as in Example 1 except that Sylwell B03 (Fuji Silysia Chemical Ltd.) was used instead of 0D.
A hard coat film having a curable resin layer having a Ra of 0.5 μm and a thickness of 4 μm was obtained.

Example 3 Instead of the coating liquid of Example 1, a curable resin layer coating liquid having the following composition was used.
Otherwise in the same manner as in Example 1, a hard coat film having a curable resin layer with Ra of 1.0 μm in JIS-B0601 and a thickness of 4 μm was obtained.

-Acrylic polyol 31.0 parts (Acridic A801P: Dainippon Ink and Chemicals, Inc.)-Polyisocyanate 12.5 parts (Barnock DN950: Dainippon Ink and Chemicals, Inc.)-Antibacterial agent, 1.8 parts (Zeomic AW10D) , Particle size of about 2 μm: Sinenen) ・ Methyl ethyl ketone 26.9 parts ・ Toluene 26.9 parts

Example 4 A resin coating containing an antibacterial agent having the following composition was prepared on one side of a 125 μm-thick polyester film, applied with a Mayer bar, and then irradiated with ultraviolet rays for 2 to 3 seconds with an ultraviolet irradiation device. To illuminate JIS-B0601
A hard coat film having a curable resin layer having a Ra of 0.3 μm and a thickness of 4 μm was obtained.

-Alicyclic epoxy resin 23.1 parts (Optomer KR550: Asahi Denka Co., Ltd.)-Antibacterial agent 1.8 parts (Silwell B03: Fuji Silysia Chemical Ltd.)-Methyl ethyl ketone 37.5 parts-Toluene 37.5 parts

Example 5 On a 125 μm thick polyester film, a curable resin layer coating solution having the following composition was applied with a Mayer bar, and then applied with an ultraviolet irradiation device.
Irradiate with ultraviolet ray for ~ 3 seconds, Ra is 0.2μm, thickness 4
A hard coat film having a μm curable resin layer was obtained.

-Polyfunctional acrylate 29.0 parts (Aronix 3700: Toagosei Co., Ltd.)-Antibacterial agent 1.8 parts (Zeomic AW10D, particle size 2 μm: Sinanen Co.)-Methyl ethyl ketone 34.6 parts-Toluene 34.6 parts

[Comparative Example 1] The amount of the antibacterial agent was doubled and Ra
Was 0.05 μm, and a hard coat film was obtained in the same manner as in Example 1 except that the coating film thickness was 20 μm.

Comparative Example 2 A hard coat film was obtained in the same manner as in Example 1 except that Ra was 4.1 μm or more by reducing the thickness of the coating film.

The hard coat films obtained in Examples 1 to 5 and Comparative Examples 1 and 2 were evaluated as follows. Table 1 shows the results.

As for the antibacterial property, 1 ml of Escherichia coli solution (100,000 cells / ml) and Staphylococcus aureus solution (100,000 cells / ml) were dropped on each hard coat film and incubated at 35 ° C. for 24 hours. Then, the bacterial solution was washed away with physiological saline, and the number of E. coli and the number of Staphylococcus aureus present in this solution were measured.

The "pencil hardness" was measured using Haydon-14 (Shinto Kagaku Co., Ltd.) according to the pencil scratch test in JIS-K5400.

"Ra" was measured by using a surface coder SE-3C (Kosaka Laboratory Ltd.) according to the surface roughness measurement in JIS-B0601.

[0054]

[Table 1]

From Table 1, the hard coat films of Examples 1 to 5 have good hardness and antibacterial properties, but Comparative Example 1 does not exhibit the effect against Staphylococcus aureus. In Comparative Example 2, the coating film thickness is smaller than that in Example 1, so that the proportion of the antibacterial agent in the coating film inevitably increases and, as a result, Ra increases. That is, the ratio of the resin is small, so the hardness is lowered.

[0056]

As is apparent from the above examples, according to the present invention, R on the surface of the curable resin layer containing the antibacterial agent is
By controlling a, a hard coat film capable of exhibiting stable antibacterial performance can be provided.

Claims (2)

[Claims] 1. A Ra according to JIS-B0601 of 0.1 to 3.0 on one side or both sides of a plastic film.
A hard coat film having a curable resin layer having an antibacterial property and having a pencil hardness of H or more according to JIS-K5400. 2. The hard coat film according to claim 1, wherein the curable resin layer is a layer formed of at least a photopolymerizable prepolymer, a photopolymerizable monomer, a photopolymerization initiator and an antibacterial agent. .