JP3577145B2 - Hard coat film - Google Patents

Description

【００５５】
表１より、実施例１〜５のハードコートフィルムについては、硬度、抗菌性とも良好であるが、比較例１については、黄色ブドウ球菌に対する効果があまり発揮されていない。比較例２については、実施例１より塗膜厚が薄くなっているので、必然的に塗膜中の抗菌剤の占める割合が多くなり、その結果Ｒａが大きくなっている。つまり樹脂の占める割合が少なくなっているので硬度が低下している。
【００５６】
【発明の効果】
以上の実施例からも明らかなように、本発明によれば、抗菌剤を含有する硬化型樹脂層表面のＲａを制御することで、安定した抗菌性能を発揮できるハードコートフィルムを提供することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hard coat film having antibacterial properties, and in particular, a hard coat film having antibacterial properties suitable for a surface substrate such as a membrane switch, a flat panel display, a display screen which can be seen through or a pen input type touch panel. About the film.
[0002]
[Prior art]
In recent years, membrane switches have been used for operation panels of various devices. When operating such a membrane switch, if bacteria and the like proliferate on the surface thereof, the possibility of infection with a disease increases. In particular, on an operation panel of a home shower toilet, a microwave oven, a washing machine, or the like, there is a high possibility that bacteria are likely to adhere, and an environment in which bacteria such as moderate temperature and humidity easily propagate is often provided.
[0003]
Further, the membrane switch is also used in a large number of devices operated by an unspecified number of people, such as a copier and an air conditioner switch. In such a device, the possibility of bacteria being attached is still high.
[0004]
Furthermore, recently, nosocomial infection, in which bacteria such as MRSA (methicillin-resistant Staphylococcus aureus) infect hospitals, has become a problem. In order to prevent such bacterial infection, it is necessary to prevent the growth of bacteria on the operation panel.
[0005]
On the other hand, the conventional antibacterial film is not able to exhibit stable antibacterial performance because a film obtained by uniformly mixing an antibacterial agent into a resin is molded into a film shape (Japanese Utility Model Application Laid-Open No. 7-9952). Was.
[0006]
In particular, when such an antibacterial film is used in applications such as a membrane switch used by an unspecified number of people in various modes, scratches are easily caused due to lack of scratch resistance, abrasion resistance and the like. In addition, there is a disadvantage that the surface appearance of a switch or the like is significantly impaired.
[0007]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide a hard coat film that can exhibit more stable antibacterial performance while maintaining the performance as a so-called hard coat material such as scratch resistance and abrasion resistance.
[0008]
[Means for Solving the Problems]
The hard coat film of the present invention has an antibacterial property in which Ra in JIS-B0601 is 0.1 to 3.0 μm and pencil hardness in JIS-K5400 is H or more on one or both sides of the plastic film. It has a mold resin layer.
[0009]
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
Hereinafter, the hard coat film of the present invention will be described in detail.
[0011]
Any plastic film can be used as long as it has a function as a support, and examples thereof include films or sheets made of polyethylene terephthalate, polybutylene terephthalate, polycarbonate, acryl, triacetate, and the like. Of these, stretching, particularly biaxially stretching, is preferred because mechanical strength and dimensional stability are improved. The thickness can be appropriately selected depending on the material to be applied, but is generally 25 to 250 μm.
[0012]
The curable resin layer formed on one or both surfaces of the plastic film has a role of imparting scratch resistance and antibacterial property to the coating film.
[0013]
Such a curable resin layer having antibacterial properties is formed mainly of a polymer binder composed of a thermosetting resin or an ionizing radiation curable resin and an antibacterial agent containing an antibacterial metal ion.
[0014]
In particular, in the present invention, Ra on the surface of the curable resin layer containing an antibacterial agent is adjusted within a certain range in order to effectively exhibit antibacterial performance. This will be described later.
[0015]
As the thermosetting resin, an organopolysiloxane-based resin, a melamine-based resin, a polyurethane-based resin, or the like can be used, but it is preferable to use an ionizing radiation-curable resin from the viewpoint of working environment and productivity.
[0016]
The ionizing radiation-curable resin is formed from a paint containing at least a resin that is cured by irradiation with an electron beam or ultraviolet rays. Specifically, it contains a photopolymerizable prepolymer, a photopolymerizable monomer, and a photopolymerization initiator, and further contains a sensitizer, a non-reactive resin, an additive such as a leveling agent, and a solvent as necessary. It is.
[0017]
The structure and molecular weight of the photopolymerizable prepolymer relate to the curing of the ionizing radiation-curable coating material, and determine the properties of the ionizing radiation-curable resin, such as adhesiveness, hardness, and crack resistance. The photopolymerizable prepolymer undergoes radical polymerization when the acryloyl group introduced into the skeleton is irradiated with ionizing radiation. Those cured by radical polymerization are particularly preferred because they have a high curing rate and a high degree of freedom in resin design.
[0018]
As the photopolymerizable prepolymer, an acrylic prepolymer having an acryloyl group is particularly preferable, and an acrylic prepolymer having two or more acryloyl groups in one molecule and having a three-dimensional network structure is preferable. As the acrylic prepolymer, urethane acrylate, epoxy acrylate, melamine acrylate, polyester acrylate and the like can be used.
[0019]
The photopolymerizable monomer is used for diluting a high-viscosity photopolymerizable prepolymer, lowering the viscosity and improving workability, and for imparting coating strength as a crosslinking agent.
[0020]
Examples of the photopolymerizable monomer include monofunctional acrylic monomers such as 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and butoxyethyl acrylate, 1,6-hexadiol acrylate, neopentyl glycol diacrylate, and hydroxypropyl acrylate. One or two or more of bifunctional acrylic monomers such as biphosphate neopentyl glycol acrylate, and polyfunctional acrylic monomers such as dipentaerythritol hexaacrylate, trimethylpropane triacrylate, and pentaerythritol triacrylate are used.
[0021]
In addition, when the mixing amount of the photopolymerizable monomer increases, the coating film becomes harder than necessary. Therefore, 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, the hardness is adjusted by mixing a non-reactive resin such as a thermosetting resin having excellent flexibility, a thermoplastic acrylic resin, or an epoxy resin. be able to.
[0022]
The photopolymerization initiator is added to start the reaction of the acryloyl group in a short time by irradiation with ionizing radiation and promote 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. Types of photopolymerization initiators include those that undergo radical polymerization by cleavage, those that undergo radical polymerization by extracting hydrogen, and those that undergo cationic polymerization by generating ions.
[0023]
Examples of the photopolymerization initiator include, for example, benzoin ether-based, ketal-based, acetophenone-based, thioxanthone-based radical-type photopolymerization initiators, diazonium salts, diaryliodonium salts, triarylsulfonium salts, and the like, or composite cationic photopolymerization. Examples of the initiator include one or more of these. The photopolymerization initiator is used in a mixture of 2 to 10% by weight, preferably 3 to 6% by weight, based on the solid resin component.
[0024]
In order to cure the ionizing radiation-curable paint, it is irradiated with an electron beam or ultraviolet rays.
[0025]
Irradiation with an electron beam can be performed by using a scanning or curtain type electron beam accelerator and irradiating an electron beam having an acceleration voltage of 1000 keV or less, preferably energy of 100 to 300 keV, and a wavelength region of 100 nm or less. it can.
[0026]
When irradiating 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 to emit ultraviolet light having an energy of 50 to 300 kcal / mol in a wavelength region of 100 to 400 nm, preferably 200 to 400 nm. Irradiate.
[0027]
As the antibacterial agent used in the present invention, zeolite-based solid particles holding at least one kind of metal ion such as gold, silver, copper, zinc, lead, platinum, antimony, nickel, aluminum, cadmium, manganese, or the like, or the metal ion And solid particles carrying a metal complex. In particular, zeolite containing silver ions or silver complex salts is preferable in consideration of safety to the human body.
[0028]
The shape of the antibacterial agent is preferably in the form of particles, particularly spherical. This is for imparting uniform surface irregularities to the surface of the curable resin layer.
[0029]
In the present invention, it is necessary that the surface unevenness of the curable resin layer containing the antibacterial agent is controlled. That is, Ra of the curable resin layer in JIS-B0601 is in the range of 0.1 to 3.0 μm, preferably in the range of 0.3 to 1.5 μm, and more preferably in the range of 0.5 to 1.0 μm. It is suitable.
[0030]
By setting the Ra within a certain range, the antibacterial agent can be protruded from the surface of the curable resin layer to an extent that the antibacterial performance can be effectively exhibited.
[0031]
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 cannot exert the antibacterial effect. If it is too large, in other words, if it exceeds 3.0 μm, the ratio of the antibacterial agent jumping out of the surface of the curable resin layer will increase, and it will be easily lost due to a little friction, etc. This is because hard coat performance, that is, H or more cannot be obtained with a pencil hardness described below. In particular, by adjusting Ra to a range of 0.5 to 1.0 μm, it is possible to obtain a transparent curable resin layer usable for a transparent touch panel or the like.
[0032]
The average particle size of the antibacterial agent can be 0.1 to 50 µm, preferably 1 to 20 µm. If the thickness is less than 0.1 μm, the antibacterial agent is buried in the coating film and cannot exert an antibacterial effect, while if it exceeds 50 μm, the proportion of the antibacterial agent in the coating film increases and the hardness decreases. .
[0033]
The addition amount of the antibacterial agent is in the range of 0.1 to 30% by weight, and preferably in the range of 2 to 20% by weight, based on the total weight of the resin. If the amount is less than 0.1% by weight, the antibacterial agent in the resin coating is too sparse and sufficient antibacterial performance cannot be obtained, while if it exceeds 30% by weight, the ratio of the antibacterial agent in the resin coating is high. This is because the performance such as scratch resistance and wear resistance is reduced.
[0034]
In order to obtain performance as a so-called hard coat material such as scratch resistance and abrasion resistance, the hardness of the curable resin layer must be at least H, more preferably 2H or more in pencil hardness according to JIS-K5400. In particular, 2H to 5H is more preferable from the viewpoint of scratch resistance, wear resistance, and bending property. When the above-mentioned Ra exceeds 3.0 μm, the pencil hardness of the resin layer becomes less than H, so that the resin layer is easily scratched and the surface appearance when used as a surface substrate is significantly impaired.
[0035]
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 paint containing an antibacterial agent is applied to a plastic film and irradiated with an electron beam or ultraviolet rays. Formed.
[0036]
The application of the ionizing radiation-curable paint to the plastic film can be performed by a usual coating method, for example, a coating method such as bar, blade, gravure, spin, and spray.
[0037]
When an ionizing radiation-curable paint is cured by irradiation with an electron beam or ultraviolet rays, the presence of oxygen and the thickness of the coating film are closely related to the curing. Radicals generated by the irradiation with ionizing radiation supplement oxygen, thereby suppressing curing. For this reason, when the thickness of the coating film is small, the surface area occupying the coating film volume increases, and the coating is easily affected by curing in the air. In addition, if the thickness of the coating film is large, ionizing radiation hardly penetrates into the interior, and even if the surface is cured, the interior is not sufficiently cured, and the presence of an uncured portion at the application interface causes the curable resin layer to be hardened. Poor adhesion between the film and the plastic film. In order to prevent such curing inhibition and uncuring, especially in the case of electron beam irradiation, irradiation can be performed under an inert gas such as N ₂ gas. In addition, curing inhibition can be prevented by adjusting the thickness of the coating film, selecting a photopolymerizable prepolymer and a photopolymerizable monomer having a high curing rate, and increasing the mixing amount of the photopolymerization initiator.
[0038]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. Note that “parts” and “%” are based on weight unless otherwise specified. Ra represents the center line average surface roughness.
[0039]
[Example 1]
On a 125 μm-thick polyester film, a curable resin layer coating liquid having the following composition was applied using a Meyer bar, and was sufficiently cured at 150 ° C., and Ra in JIS-B0601 was 0.5 μm and the thickness was 0.5 μm. A hard coat film having a 4 μm-thick curable resin layer was obtained.
[0040]
・ 77.2 parts of organopolysiloxane resin (Si coat A2: Daihachi Chemical Industry Co., Ltd.)
-Antibacterial agent 1.8 parts (Zeomic AW10D, particle size 2 μm: Sinanen)
・ Methyl ethyl ketone 21.0 parts
[Example 2]
A curable resin layer having a Ra of 0.5 μm in JIS-B0601 and a thickness of 4 μm in the same manner as in Example 1 except that Silwell B03 (Fuji Silysia Chemical Ltd.) was used instead of Zeomic AW10D of Example 1. Was obtained.
[0042]
[Example 3]
Instead of the coating liquid of Example 1, a coating liquid for a curable resin layer having the following composition was used, and in the same manner as in Example 1 except that Ra in JIS-B0601 was 1.0 μm, and the thickness was 1.0 μm. A hard coat film having a 4 μm curable resin layer was obtained.
[0043]
Acrylic polyol 31.0 parts (Acrydic A801P: Dainippon Ink and Chemicals, Inc.)
・ 12.5 parts of polyisocyanate (Bernock DN950: Dainippon Ink and Chemicals, Inc.)
・ 1.8 parts of antibacterial agent (Zeomic AW10D, particle size about 2 μm: Sinanen)
・ 26.9 parts of methyl ethyl ketone ・ 26.9 parts of toluene
[Example 4]
On one surface of a polyester film having a thickness of 125 μm, a resin coating containing an antibacterial agent having the following composition was prepared, applied with a Meyer bar, and irradiated with ultraviolet light for 2 to 3 seconds using an ultraviolet irradiation device, according to JIS-B0601. In Example 1, a hard coat film having a curable resin layer having a Ra of 0.3 μm and a thickness of 4 μm was obtained.
[0045]
・ 23.1 parts of alicyclic epoxy resin (OPTMER KR550: Asahi Denka Kogyo Co., Ltd.)
・ 1.8 parts of antibacterial agent (Silwell B03: Fuji Silysia Chemical Ltd.)
・ Methyl ethyl ketone 37.5 parts ・ Toluene 37.5 parts
[Example 5]
A coating liquid for a curable resin layer having the following composition was applied on a 125 μm-thick polyester film with a Mayer bar, and irradiated with ultraviolet light for 2 to 3 seconds using an ultraviolet irradiation device to obtain Ra of 0.2 μm. Thus, a hard coat film having a curable resin layer having a thickness of 4 μm was obtained.
[0047]
・ 29.0 parts of polyfunctional acrylate (Aronix 3700: Toagosei Co., Ltd.)
-Antibacterial agent 1.8 parts (Zeomic AW10D, particle size 2 μm: Sinanen)
・ 34.6 parts of methyl ethyl ketone ・ 34.6 parts of toluene
[Comparative Example 1]
A hard coat film was obtained in the same manner as in Example 1 except that the amount of the antibacterial agent was doubled, Ra was 0.05 μm, and the coating thickness was 20 μm.
[0049]
[Comparative Example 2]
A hard coat film was obtained in the same manner as in Example 1 except that Ra was increased to 4.1 μm or more by reducing the thickness of the coating film.
[0050]
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.
[0051]
"Antibacterial property" was obtained by dropping 1 ml of Escherichia coli solution (100,000 cells / ml) and Staphylococcus aureus solution (100,000 cells / ml) on each hard coat film and culturing at 35 ° C for 24 hours. Thereafter, the bacterial solution was washed away with physiological saline, and the number of Escherichia coli and the number of Staphylococcus aureus present in this solution were measured.
[0052]
"Pencil hardness" was measured using Haydon-14 (Shinto Kagaku) according to a pencil scratch test in JIS-K5400.
[0053]
"Ra" was measured using a surface coder SE-3C (Kosaka Laboratories) in accordance with the surface roughness measurement in JIS-B0601.
[0054]
[Table 1]

[0055]
Table 1 shows that the hard coat films of Examples 1 to 5 have good hardness and antibacterial properties, but Comparative Example 1 does not show much effect on Staphylococcus aureus. In Comparative Example 2, since the thickness of the coating film was smaller than that in Example 1, the proportion of the antibacterial agent in the coating film necessarily increased, and as a result, Ra increased. That is, since the proportion of the resin is small, the hardness is low.
[0056]
【The invention's effect】
As is clear from the above examples, according to the present invention, it is possible to provide a hard coat film that can exhibit stable antibacterial performance by controlling Ra on the surface of a curable resin layer containing an antibacterial agent. it can.

Claims (2)

One side or both sides of the plastic film has a curable resin layer having an antibacterial property in which Ra in JIS-B0601 is 0.1 to 3.0 μm and pencil hardness in JIS-K5400 is H or more. A hard coat film, characterized in that: 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.