JP7800091B2 - Antiviral adhesive sheet and article with antiviral adhesive sheet - Google Patents

Description

This disclosure relates to antiviral adhesive sheets and articles equipped with antiviral adhesive sheets.

From a hygiene perspective, antibacterial treatment has traditionally been performed by applying an antibacterial composition to the surfaces of objects that people touch, such as interior materials for buildings and vehicles, office equipment, and touch panels.

Antibacterial compositions have been proposed, for example, in Patent Documents 1 and 2.
However, merely having antibacterial properties is not sufficient against viruses such as influenza viruses and novel coronaviruses. That is, the antibacterial compositions of Patent Documents 1 and 2 sometimes failed to provide satisfactory antiviral properties.

On the other hand, antiviral sheets have been proposed in Patent Documents 3 and 4.

Japanese Unexamined Patent Publication No. 63-265958 Patent No. 3551201 Patent No. 6145758 Patent No. 6229429

Due to the influence of the new coronavirus, antiviral sheets are sometimes attached to various items.
When an antiviral sheet is attached to an article, air bubbles may become trapped between the article and the antiviral sheet. Furthermore, after the antiviral sheet is attached to the article, gas may be generated from the article, causing air bubbles to form between the article and the antiviral sheet. Air bubbles present between the article and the antiviral sheet may reduce the design of the article. However, the antiviral sheets in Patent Documents 3 and 4 do not address the reduction in the design of the article due to air bubbles.

Furthermore, some antiviral agents are colored from the early stages or become colored over time. The antiviral agent in Patent Document 3 contains cuprous oxide particles and has a color derived from the reddish-brown color of cuprous oxide. Of the antiviral agents in Patent Document 4, the silver-based antiviral agent discolors to brown when exposed to light such as visible light and ultraviolet light. As such, the antiviral sheets in Patent Documents 3 and 4 do not consider at all the degradation of the design of the article due to the color of the antiviral agent.

Furthermore, antiviral sheets are required to have stable adhesion to a variety of articles, but the antiviral sheets in Patent Documents 3 and 4 do not consider adhesion to articles at all.

The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide an antiviral adhesive sheet that suppresses a decrease in the design of an article and has stable adhesion to the article. It also aims to provide an article with an antiviral adhesive sheet that suppresses a decrease in the design of the article and has stable adhesion to the antiviral adhesive sheet.

In order to solve the above problems, the present disclosure provides the following [1] to [2].
[1] An antiviral pressure-sensitive adhesive sheet comprising a laminate having, in this order, a surface protective layer containing a binder component and an antiviral agent, a light-transmitting base layer, and a pressure-sensitive adhesive layer,
the light-transmitting substrate layer contains a polypropylene-based resin substrate,
An antiviral adhesive sheet, wherein the antiviral agent is an organic antiviral agent.
[2] An article with an antiviral adhesive sheet, comprising the antiviral adhesive sheet according to [1] attached to an article.

The antiviral adhesive sheet of the present disclosure can prevent a decrease in the design quality of an article and can provide stable adhesion to the article. Furthermore, an article equipped with the antiviral adhesive sheet of the present disclosure can prevent a decrease in the design quality of the article and can provide stable adhesion between the article and the antiviral adhesive sheet.

FIG. 1 is a cross-sectional view showing one embodiment of an antiviral adhesive sheet of the present disclosure. FIG. 2 is a cross-sectional view showing another embodiment of the antiviral adhesive sheet of the present disclosure. FIG. 2 is a cross-sectional view showing another embodiment of the antiviral adhesive sheet of the present disclosure. FIG. 10 is a plan view illustrating an embodiment of a groove in a pressure-sensitive adhesive layer having a groove.

This disclosure is explained in detail below.

[Antiviral adhesive sheet]
The antiviral adhesive sheet of the present disclosure is an antiviral adhesive sheet including a laminate having, in this order, a surface protective layer containing a binder component and an antiviral agent, a light-transmitting base layer, and a pressure-sensitive adhesive layer, wherein the light-transmitting base layer is a polypropylene-based resin base, and the antiviral agent is an organic antiviral agent.

Figures 1 to 3 are cross-sectional views showing one embodiment of an antiviral adhesive sheet according to the present disclosure. The antiviral adhesive sheet 100 in Figures 1 to 3 includes a laminate 10 having a surface protective layer 30, a light-transmitting substrate layer 20, and a pressure-sensitive adhesive layer 40, in this order. In Figures 1 to 3, the surface protective layer 30 includes a binder component 31 and an antiviral agent 32. In Figures 1 to 3, the antiviral adhesive sheet 100 further includes a separator 50. In Figures 1 to 3, the separator 50 is located on the opposite side of the pressure-sensitive adhesive layer 40 from the light-transmitting substrate layer 20.

When the viral adhesive sheet of the present disclosure simultaneously exhibits antibacterial and antifungal properties in addition to exhibiting antiviral properties, it can also be used as an antibacterial sheet and an antifungal sheet.
Generally, even for sheets made of the same material and layer structure, the correlation between their exhibited "antiviral,""antibacterial," and "antifungal" properties may be effective or ineffective depending on the type of virus, bacteria, or mold in question; the environmental conditions; the required level of antiviral, antibacterial, or antifungal properties; etc. For this reason, the antiviral adhesive sheet of the present disclosure may be applicable not only to antiviral applications but also to antibacterial applications, depending on the type of bacteria, environmental conditions, and the required level of antibacterial properties. Note that, because mold is a type of fungus, the antiviral adhesive sheet of the present disclosure may also be applicable to antifungal applications, depending on the type of mold, environmental conditions, and the required level of antifungal properties.

In this disclosure, "antiviral" means that the antiviral activity value measured by the following method is greater than 0.0. The antiviral adhesive sheet of the present disclosure preferably has an antiviral activity value of 1.0 or greater, and more preferably 2.0 or greater. The following method complies with ISO 21702.

<Method for measuring antiviral activity value>
For the antiviral-treated and untreated products, 5 cm square test pieces are prepared. 0.4 ml of virus fluid is dropped onto the surface protective layer side of the test piece, and the test piece is covered with a 4 cm square film. This test piece is left to stand for 24 hours in an environment of 25°C and 90% RH. After standing, the virus fluid dropped onto the test piece is washed off and recovered, and the virus infectivity is measured. The antiviral activity value is calculated using the following formula (1):
R=Ut-At (1)
R: Antiviral activity value Ut: average common logarithm of virus infectivity (PFU/cm ² ) of untreated product after standing for 24 hours At: average common logarithm of virus infectivity (PFU/cm ² ) of antiviral treated product after standing for 24 hours

<Laminate>
The antiviral pressure-sensitive adhesive sheet of the present disclosure includes a laminate having, in this order, a surface protective layer, a light-transmitting substrate layer, and a pressure-sensitive adhesive layer.

The surface protection layer forms one surface of the laminate, and the pressure-sensitive adhesive layer forms the other surface of the laminate.
The laminate may have a functional layer between the surface protective layer and the light-transmitting substrate layer and/or between the light-transmitting substrate layer and the pressure-sensitive adhesive layer. Examples of the functional layer include a primer layer.

Specific examples of the layer structure of the laminate include the following (1) and (2).
(1) A laminate having a surface protective layer, a light-transmitting substrate layer, and a pressure-sensitive adhesive layer in this order.
(2) A laminate having a surface protective layer, a primer layer, a light-transmitting substrate layer, and a pressure-sensitive adhesive layer in this order.

In the antiviral pressure-sensitive adhesive sheet of the present disclosure, the haze value of the laminate measured in accordance with JIS K7136:2000 is preferably 40% or more, more preferably 50% or more, and even more preferably 55% or more. Increasing the haze value of the laminate makes it easier to identify the location where the antiviral pressure-sensitive adhesive sheet is attached. Furthermore, when the pressure-sensitive adhesive layer is a porous layer, increasing the haze value of the laminate makes it difficult to visually detect thickness variations in the porous pressure-sensitive adhesive layer, which is preferable in terms of improving the appearance.
On the other hand, if the haze value of the laminate is too high, the design applied to the article may become difficult to see. Therefore, the haze value of the laminate is preferably 90% or less, more preferably 75% or less, and even more preferably 65% or less.

In the configuration requirements shown in this specification, when multiple upper limit options and multiple lower limit options are shown for each of the numerical values, one selected from the upper limit options and one selected from the lower limit options can be combined. For example, in the case of the haze value of the above laminate, 40% or more and 90% or less, 40% or more and 75% or less, 40% or more and 65% or less, 50% or more and 90% or less,
Examples of embodiments include numerical ranges of 50% to 75%, 50% to 65%, 55% to 90%, 55% to 75%, and 55% to 65%.

To improve the visibility of the article, the laminate preferably has a total light transmittance of 80% or more, more preferably 85% or more, and even more preferably 90% or more, as measured in accordance with JIS K7361-1:1997.

The laminate preferably has an oxygen permeability of 50 cc/ ^m2 day atm or more, more preferably 75 cc/ ^m2 day atm or more, and even more preferably 100 cc/m2 ^day atm or more, as measured in accordance with JIS K7126-2: 2006. In this specification, the conditions for measuring oxygen permeability are a temperature of 23°C and a relative humidity of 90%.
The oxygen permeability can be measured, for example, by an oxygen permeability measuring device (trade name: OX-TRAN) manufactured by MOCON (MOCON method).
By setting the oxygen permeability within the above range, air bubbles between the article and the antiviral pressure-sensitive adhesive sheet can be easily removed.
There is no particular upper limit to the oxygen permeability of the laminate, but it is preferably 2000 cc/m ² ·day·atm or less.

《Light-transparent base material layer》
The light-transmitting substrate layer serves as a support for the surface protective layer and the pressure-sensitive adhesive layer.
The antiviral pressure-sensitive adhesive sheet of the present disclosure uses a substrate layer containing a polypropylene-based resin substrate as the light-transmitting substrate layer.

The light-transmitting substrate layer may contain two or more resin substrates such as polypropylene-based resin substrates, but preferably contains only one resin substrate in order to increase gas permeability. That is, the light-transmitting substrate layer preferably contains only one polypropylene-based resin substrate as the resin substrate.
The light-transmitting substrate layer may have a layer other than the polypropylene-based resin substrate. For example, the light-transmitting substrate layer may have a resin layer on the polypropylene-based resin substrate. The resin layer has a role of adjusting haze, for example.

Polypropylene-based resin substrates are highly permeable to gas. Therefore, even if air bubbles are introduced when the antiviral pressure-sensitive adhesive sheet is attached to an article, or if bubbles are generated due to gas being generated from the article after the antiviral sheet is attached to the article, the air bubbles can be easily removed. As a result, polypropylene-based resin substrates can easily prevent a decrease in the design of the article. Furthermore, because polypropylene-based resin substrates have good shape-following properties, they can provide stable adhesion to articles with curved or uneven surfaces.

The gas permeability of polypropylene-based resin substrates can be adjusted by the resin formulation, the crystallinity of the resin, the particles in the substrate, and the thickness of the substrate, etc.

The polypropylene resin may be a homopolymer of propylene, or a copolymer of propylene and another comonomer copolymerizable with propylene (e.g., α-olefins such as ethylene, 1-butene, 1-hexene, and 1-octene; vinyl acetate, vinyl alcohol, etc.). These polypropylenes may be used alone or in combination of two or more.

When a propylene homopolymer is used as the resin constituting the polypropylene-based resin substrate, the higher the crystallinity of the polymer, the lower the gas permeability tends to be, and the lower the crystallinity of the polymer, the higher the gas permeability tends to be. When the thickness of the polypropylene-based resin substrate is in the range described below, the crystallinity of the polymer is preferably 30% or more, more preferably 40% or more, and the upper limit is preferably 80% or less, more preferably 70% or less.
When a propylene homopolymer is used as the resin constituting the polypropylene-based resin substrate, the gas permeability of the polymer can also be adjusted by adjusting the mass ratio of isotactic polypropylene to atactic polypropylene. Generally, the gas permeability of the polymer decreases when isotactic polypropylene is added compared to when the proportion of atactic polypropylene in polypropylene is 100 mass%.

The polypropylene-based resin substrate may contain particles. By containing particles in the polypropylene-based resin substrate, the gas permeability of the polypropylene-based resin substrate can be easily increased. Furthermore, by containing particles in the polypropylene-based resin substrate, the internal haze of the polypropylene-based resin substrate can be easily increased. Note that if the particle content is too high, the polypropylene-based resin substrate may become embrittled.

The polypropylene resin substrate may contain additives such as ultraviolet absorbers, light stabilizers, antioxidants, and antistatic agents.

The thickness of the polypropylene-based resin substrate is preferably 5 μm or more, more preferably 20 μm or more, and even more preferably 50 μm or more, to improve strength and handleability and increase the haze value of the laminate. The thickness of the polypropylene-based resin substrate is preferably 250 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less, to improve shape conformability and facilitate high gas permeability.

As mentioned above, the light-transmitting substrate layer may have a resin layer on a polypropylene-based resin substrate. The resin layer has the role of adjusting haze, for example. The resin layer preferably contains a binder resin and particles.

Examples of the binder resin of the resin layer include resins similar to those exemplified as binder resins of the primer layer described below.
The particles in the resin layer may be general-purpose organic particles or general-purpose inorganic particles. In order to increase the internal haze of the resin layer, the particles preferably have a refractive index that is significantly different from that of the binder resin. The average particle size of the particles is preferably 0.1 μm or more and 5.0 μm or less, and more preferably 0.2 μm or more and 3.0 μm or less.
The content of the particles relative to the binder resin may be adjusted appropriately taking into consideration the desired internal haze and coating strength of the resin layer.

The thickness of the resin layer is preferably 0.01 μm or more and 10 μm or less, more preferably 0.7 μm or more and 8 μm or less, and even more preferably 1.0 μm or more and 6 μm or less.

To improve the visibility of the article, the light-transmitting substrate layer preferably has a total light transmittance of 80% or more, more preferably 85% or more, and even more preferably 90% or more, as measured in accordance with JIS K7361-1:1997.

In this specification, the total light transmittance, internal haze value, and haze can be calculated, for example, as follows.
(1) A sample is cut out from a defect-free portion of an antiviral pressure-sensitive adhesive sheet, or from a defect-free portion of a laminate formed by stacking layers other than the pressure-sensitive adhesive layer among the layers constituting the laminate.
(2) The total light transmittance, internal haze value, and haze are measured at 20 points on the sample. The average values of the 20 measured points are used as the total light transmittance, internal haze value, and haze of each sample.

The polypropylene resin substrate preferably has an oxygen permeability measured in accordance with JIS K7126-2:2006 of 100 cc/ ^m2 ·day·atm or more, more preferably 150 cc/ ^m2 ·day·atm or more, and even more preferably 200 cc/ ^m2 ·day·atm or more.
By setting the oxygen permeability within the above range, air bubbles between the article and the antiviral pressure-sensitive adhesive sheet can be easily removed.
There is no particular upper limit to the oxygen permeability of the polypropylene-based resin substrate, but it is preferably 2500 cc/m ² ·day·atm or less.

To improve adhesion between the polypropylene resin substrate and layers that come into contact with the polypropylene resin substrate, one or both sides of the polypropylene resin substrate may be subjected to a physical or chemical treatment to facilitate adhesion, or an easy-adhesion layer may be provided.

《Surface protective layer》
The surface protective layer contains a binder component and an antiviral agent.
The surface protective layer may be formed on the entire surface of the light-transmitting base layer, or may be formed on a part of the surface. The area ratio of the surface protective layer to the surface of the light-transmitting base layer is preferably 80% or more, more preferably 90% or more, and most preferably 100%.

To enhance the antiviral property, as shown in FIGS. 1 to 3 , it is preferable that at least a part of the antiviral agent protrudes from the surface of the surface protective layer opposite the light-transmitting base layer (hereinafter referred to as the "surface of the surface protective layer").
The distribution of the antiviral agent in the thickness direction of the surface protective layer may be unevenly distributed on the surface of the surface protective layer as shown in FIGS. 1 to 3 , or may be dispersed approximately uniformly in the thickness direction of the surface protective layer, or may be distributed so that the concentration of the antiviral agent increases from the light-transmitting base material layer side toward the surface of the surface protective layer.
In the in-plane direction of the surface protective layer, the antiviral agent is preferably distributed throughout the entire surface protective layer. The distribution state in the in-plane direction may be such that there are regions where the antiviral agent is densely concentrated and regions where the antiviral agent is sparsely distributed, but it is preferable that the antiviral agent is distributed approximately uniformly.

Taking into consideration factors such as scratch resistance, processability, and ease of application to articles, the thickness of the surface protection layer is preferably 1 μm or more and 100 μm or less. The thickness of the surface protection layer is more preferably 2 μm or more and 50 μm or less, even more preferably 3 μm or more and 30 μm or less, and particularly preferably 5 μm or more and 20 μm or less.

- Binder component -
The binder component is preferably a resin in order to improve processability. Examples of resins used as binder components include thermoplastic resins and cured products of curable resin compositions. Among resins, cured products of curable resin compositions are preferred in order to improve scratch resistance. In this specification, the term "cured product of a curable resin composition" may be abbreviated as "cured product."

Examples of cured products of curable resin compositions include cured products of thermosetting resin compositions and cured products of ionizing radiation-curable resin compositions. Cured products of ionizing radiation-curable resin compositions are preferred for their durability of antiviral properties and improved production efficiency.

A thermosetting resin composition is a composition that contains at least a thermosetting resin and cures when heated. Examples of thermosetting resins include acrylic resins, urethane resins, phenolic resins, urea-melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. In addition to these thermosetting resins, thermosetting resin compositions also contain curing agents, curing catalysts, and other additives as needed.

Ionizing radiation-curable resin compositions are compositions containing compounds having ionizing radiation-curable functional groups (hereinafter also referred to as "ionizing radiation-curable compounds"). Representative examples of ionizing radiation-curable resin compositions include electron beam-curable resin compositions and ultraviolet light-curable resin compositions. Among these, electron beam-curable resin compositions are preferred due to their advantages, such as high scratch resistance, little odor because no polymerization initiator is required, and resistance to coloration.

The ionizing radiation-curable functional group is a group that crosslinks and cures upon irradiation with ionizing radiation, and preferred examples thereof include functional groups having an ethylenic double bond such as a (meth)acryloyl group, a vinyl group, and an allyl group. Further examples of the ionizing radiation-curable functional group include an epoxy group and an oxetanyl group.
In this specification, the term "(meth)acryloyl group" refers to an acryloyl group or a methcroyl group, and the term "(meth)acrylate" refers to an acrylate or a methacrylate.

Ionizing radiation refers to electromagnetic waves or charged particle beams that have an energy quantum capable of polymerizing or crosslinking molecules. Ionizing radiation typically includes ultraviolet (UV) rays or electron beams (EB), but also includes other types of electromagnetic waves such as X-rays and gamma rays, as well as charged particle beams such as alpha rays and ion beams.

The ionizing radiation-curable compound can be appropriately selected from polymerizable monomers and polymerizable oligomers that have conventionally been used as ionizing radiation-curable resins. The ionizing radiation-curable compound is preferably a compound having two or more ethylenically unsaturated bond groups, and even more preferably a polyfunctional (meth)acrylate compound having two or more ethylenically unsaturated bond groups. Either a monomer or an oligomer can be used as the polyfunctional (meth)acrylate compound. Among these, oligomers are preferred due to their excellent mechanical properties, flexibility, and suitability for application. In addition to the oligomer, a monomer can also be added to adjust viscosity.

For scratch resistance, processability, and antiviral properties, the weight-average molecular weight of the oligomer of a multifunctional (meth)acrylate compound is preferably 1,000 to 10,000, more preferably 2,000 to 6,000. The number of functional groups per oligomer molecule is preferably 2 to 10, more preferably 2 to 6. Among the multifunctional (meth)acrylate compounds, examples of bifunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxydiacrylate, bisphenol A tetrapropoxydiacrylate, and 1,6-hexanediol diacrylate.

Examples of trifunctional or higher (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and isocyanuric acid-modified tri(meth)acrylate.

Examples of the polyfunctional (meth)acrylate oligomer include acrylate polymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate.
Among these, urethane (meth)acrylate oligomers are preferred for reasons such as ensuring coating film hardness and toughness. The urethane (meth)acrylate oligomer preferably contains a caprolactone-modified urethane (meth)acrylate oligomer. By including a caprolactone-modified urethane (meth)acrylate oligomer, flexibility can be imparted while ensuring coating film hardness and toughness, making it easier to improve processability. The proportion of the caprolactone-modified urethane (meth)acrylate oligomer in the urethane (meth)acrylate oligomer is preferably 10% by mass or more and 90% by mass or less, and more preferably 20% by mass or more and 80% by mass or less.
Urethane (meth)acrylates can be obtained, for example, by reacting a polyhydric alcohol and an organic diisocyanate with a hydroxy (meth)acrylate.

The above ionizing radiation-curable compounds can be used alone or in combination of two or more.

When the ionizing radiation curable compound is an ultraviolet ray curable compound, the ionizing radiation curable resin composition preferably contains additives such as a photopolymerization initiator and a photopolymerization accelerator.
The photopolymerization initiator may be one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzil dimethyl ketal, benzoyl benzoate, α-acyloxime ester, thioxanthones, and the like.
The photopolymerization accelerator can reduce polymerization inhibition caused by air during curing and increase the curing rate, and examples thereof include one or more selected from p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester, and the like.

The content of the cured product of the curable resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and most preferably 100% by mass, based on the total amount of binder components.

-Antiviral agent-
The antiviral pressure-sensitive adhesive sheet of the present disclosure uses an organic antiviral agent as the antiviral agent. The organic antiviral agent can suppress discoloration at an early stage and discoloration over time, and therefore can easily suppress deterioration of the design of the article. The organic antiviral agent may be used alone or in combination of two or more types.

Examples of organic antiviral agents include one or more selected from the following (1) to (3). These organic antiviral agents are preferably present in the form of particles in the surface protective layer in order to improve the gas permeability in the surface protective layer and to facilitate increasing the haze value. The shape of the particles is not particularly limited, and examples include spheres, ellipsoids, polyhedrons, and scales.
(1) Antiviral agents containing imidazole compounds (2) Antiviral agents containing styrene polymer derivative compounds and unsaturated carboxylic acid derivative compounds (3) Antiviral agents containing styrene resins

(1) Antiviral Agents Containing Imidazole Compounds Imidazole compounds are compounds that contain an imidazole skeleton as a structural unit of the molecule. In the present disclosure, it is preferable to use, among various imidazole compounds, those that maintain the particle shape within the surface protective layer. Imidazole compounds that easily maintain the particle shape are preferably those that are poorly soluble in water and organic solvents, and examples thereof include methyl benzimidazol-2-ylcarbamate (also known as carbendazim) and polymerized imidazole compounds.
However, care must be taken because even methyl benzimidazol-2-ylcarbamate (also known as carbendazim) and polymerized imidazole compounds may dissolve in certain solvents. For example, for methyl benzimidazol-2-ylcarbamate (also known as carbendazim), it is preferable to use methyl ethyl ketone, ethyl acetate, or the like as a solvent.

(2) Antiviral Agent Comprising a Styrene Polymer Derivative Compound and an Unsaturated Carboxylic Acid Derivative Compound In the present disclosure, the "antiviral agent comprising a styrene polymer derivative compound and an unsaturated carboxylic acid derivative compound" may be an "antiviral agent comprising a styrene polymer derivative compound and an unsaturated carboxylic acid derivative compound," or may be a "mixture of an antiviral agent comprising a styrene polymer derivative compound and an antiviral agent comprising an unsaturated carboxylic acid derivative compound," or a combination thereof.
The constituent components of the styrene polymer derivative compound and the unsaturated carboxylic acid derivative compound preferably have at least one structure selected from the group consisting of styrene, sodium sulfonate, acrylic acid, maleic acid, and fumaric acid, and more preferably have both at least one structure of styrene and sodium sulfonate and at least one structure selected from the group consisting of acrylic acid, maleic acid, and fumaric acid.

The ratio of the styrene polymer derivative compound to the unsaturated carboxylic acid derivative compound contained in the antiviral agent is not limited, but a mass ratio of 30:70 to 70:30 is preferred, and a mass ratio of 40:60 to 60:40 is even more preferred. This mass ratio makes it easier to exert antiviral properties against both enveloped and non-enveloped viruses. Furthermore, if antiviral properties are to be exerted only against enveloped viruses, it is sufficient to contain only the styrene polymer derivative compound.

The reason why an antiviral agent containing a styrene polymer derivative compound and an unsaturated carboxylic acid derivative compound exhibits antiviral activity is thought to be as follows, although it is not limited to the mechanism speculated below.
Influenza viruses invade host cells by binding to sugar chain receptors (the sugar chain ends in neuraminic acid) on the surface of the host cells, but copolymers containing styrene sulfonate have ionic groups similar to those of neuraminic acid, and therefore bind to and capture the viruses instead of the host cells, thereby preventing the viruses from binding to the receptors on the host cells and thus exerting their antiviral effects.In addition, unsaturated carboxylic acid derivative compounds generate hydroxyl groups (OH-) upon contact with water, and the hydroxyl groups are thought to exert their antiviral effects.

(3) Antiviral Agent Containing Styrene Resin The antiviral agent containing a styrene resin is an antiviral agent that does not contain the unsaturated carboxylic acid derivative compound.

In the present disclosure, the antiviral agent is preferably in the form of particles.
The average particle size of the antiviral agent is preferably 1 μm or more and 10 μm or less, more preferably 2 μm or more and 9 μm or less, and even more preferably 3 μm or more and 7 μm or less.
By making the average particle size 1 μm or more, it is possible to improve the stability of the ink for the surface protective layer, to increase the haze value of the surface protective layer, and to increase the gas permeability of the surface protective layer.
By setting the average particle size to 10 μm or less, it is possible to easily prevent the antiviral agent from excessively protruding from the surface of the surface protective layer, which makes it possible to easily prevent deterioration in the appearance, scratch resistance, and contamination resistance of the antiviral pressure-sensitive adhesive sheet, and also makes it possible to easily prevent wear on coating device components such as a coating roll and a doctor blade.
In this specification, the average particle size refers to the mass average value d50 measured in particle size distribution measurement by laser diffraction method.

When the average particle size of the antiviral agent is defined as D and the thickness of the surface protective layer is defined as T, D/T is preferably 1.0 or less, more preferably 0.8 or less, and even more preferably 0.6 or less. Setting D/T to 1.0 or less makes it easier to prevent the antiviral agent from excessively protruding from the surface of the surface protective layer.
The lower limit of D/T is not particularly limited, but is usually 0.01 or more, preferably 0.05 or more.

With regard to the content of the antiviral agent in the surface protective layer, the lower limit is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, and more preferably 2.0 parts by mass or more, and the upper limit is preferably 20.0 parts by mass or less, more preferably 15.0 parts by mass or less, more preferably 10.0 parts by mass or less, more preferably 7.5 parts by mass or less, and more preferably 5.0 parts by mass or less, relative to 100 parts by mass of the binder component.
By setting the content of the antiviral agent to 0.5 parts by mass or more, it is possible to easily achieve the desired antiviral performance and increase the haze value of the surface protective layer, and also to easily increase the gas permeability of the surface protective layer.
By setting the content of the antiviral agent to 20.0 parts by mass or less, deterioration in coating film physical properties such as coating film strength and scratch resistance can be easily suppressed, and wear of coating device components such as a coating roll and a doctor blade can be easily suppressed.

-Other ingredients-
The surface protective layer may contain additives such as antioxidants, light stabilizers, ultraviolet absorbers, anti-wear agents, and surface conditioners, as long as the effects of the present disclosure are not impaired.

Examples of the antioxidant include a phenol-based antioxidant, a sulfur-based antioxidant, a phosphorus-based antioxidant, and an amine-based antioxidant. The content of the antioxidant is preferably 0.1 parts by mass or more and 10.0 parts by mass or less, and more preferably 0.5 parts by mass or more and 5.0 parts by mass or less, relative to 100 parts by mass of the binder component.
The light stabilizer may be a hindered amine compound. The content of the light stabilizer is preferably 0.1 parts by mass or more and 10.0 parts by mass or less, and more preferably 1.0 parts by mass or more and 5.0 parts by mass or less, relative to 100 parts by mass of the binder component.
Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, and triazine-based ultraviolet absorbers, and triazine-based ultraviolet absorbers are preferred. The content of the ultraviolet absorber is preferably 0.1 parts by mass or more and 20.0 parts by mass or less, and more preferably 0.5 parts by mass or more and 15.0 parts by mass or less, relative to 100 parts by mass of the binder component.
Examples of the anti-wear agent include nanometer-sized particles such as silica and alumina. The average primary particle size of the anti-wear agent is preferably 10 nm or more, and the upper limit is preferably 700 nm or less to improve transparency. The content of the anti-wear agent is preferably 0.1 parts by mass or more and 30.0 parts by mass or less, more preferably 0.3 parts by mass or more and 10.0 parts by mass or less, relative to 100 parts by mass of the binder component.
Examples of the surface conditioner include silicone-based surface conditioners. The content of the surface conditioner is preferably 0.1 parts by mass or more and 10.0 parts by mass or less, and more preferably 0.3 parts by mass or more and 5.0 parts by mass or less, relative to 100 parts by mass of the binder component.

<<Adhesive layer>>
The pressure-sensitive adhesive layer can be formed from a general-purpose pressure-sensitive adhesive resin composition.
Examples of the pressure-sensitive adhesive layer include the following embodiments (1) to (3).
(1) A pressure-sensitive adhesive layer having a substantially flat surface opposite to the light-transmitting base layer. (2) A pressure-sensitive adhesive layer having grooves on the surface opposite to the light-transmitting base layer. (3) A porous pressure-sensitive adhesive layer.

(1) Pressure-sensitive adhesive layer having a substantially flat surface opposite to the light-transmitting base layer The antiviral pressure-sensitive adhesive sheet of Fig. 1 has a pressure-sensitive adhesive layer according to embodiment (1). The pressure-sensitive adhesive layer according to embodiment (1) can be formed, for example, by applying an adhesive resin composition to the surface of the light-transmitting base layer opposite to the surface protective layer, drying the composition, and then laminating a separator with a flat surface.
The adhesive resin composition preferably contains, for example, a resin having adhesive properties, and further contains, as necessary, a salt, a solvent, and an additive. Embodiments of the adhesive resin composition will be described later.
The pressure-sensitive adhesive layer of the embodiment (1) can more easily prevent a decrease in the visibility of the design of the article.

In the embodiment (1), the thickness of the pressure-sensitive adhesive layer is preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 75 μm or less, even more preferably 15 μm or more and 50 μm or less, and even more preferably 15 μm or more and 25 μm or less.
By setting the thickness of the pressure-sensitive adhesive layer to 5 μm or more, it is possible to easily increase adhesion to an article. By setting the thickness of the pressure-sensitive adhesive layer to 100 μm or less, it is possible to easily suppress a decrease in workability due to an increase in the total thickness of the antiviral pressure-sensitive adhesive sheet, and it is possible to easily increase the gas permeability of the antiviral pressure-sensitive adhesive sheet.

In embodiment (1), the surface opposite the light-transmitting substrate layer being substantially flat means that the arithmetic mean roughness Ra measured in accordance with JIS B0601:2001 with a cutoff value of 0.25 mm is 0.10 μm or less. Ra is preferably 0.05 μm or less.

(2) Pressure-sensitive adhesive layer having grooves on the surface of the pressure-sensitive adhesive layer opposite to the light-transmitting base layer The antiviral pressure-sensitive adhesive sheet of FIG. 2 has a pressure-sensitive adhesive layer according to embodiment (2). The pressure-sensitive adhesive layer according to embodiment (2) can be formed, for example, by applying an adhesive resin composition to the surface of the light-transmitting base layer opposite to the surface protective layer, drying the composition, and then laminating a separator having convex portions on its surface. The pressure-sensitive adhesive layer according to embodiment (2) can also be formed by applying an adhesive resin composition to a separator having convex portions on its surface, drying the composition, and then laminating a light-transmitting base layer to the pressure-sensitive adhesive layer. That is, a shape complementary to the shape of the convex portions of the separator is formed in the pressure-sensitive adhesive layer, thereby forming a pressure-sensitive adhesive layer having grooves.
The adhesive resin composition preferably contains, for example, a resin having adhesive properties, and further contains, as necessary, a salt, a solvent, and an additive. Embodiments of the adhesive resin composition will be described later.
In the pressure-sensitive adhesive layer of embodiment (2), gas escapes through the grooves, making it easy to remove air bubbles after alignment, and shortening the application time.

In the second embodiment, the thickness of the pressure-sensitive adhesive layer is preferably 15 μm or more and 120 μm or less, more preferably 25 μm or more and 100 μm or less, and even more preferably 30 μm or more and 80 μm or less.
By making the thickness of the adhesive layer 15 μm or more, it is possible to easily form grooves and increase adhesion to the article, and by making the thickness of the adhesive layer 120 μm or less, it is possible to easily prevent a decrease in workability due to an increase in the total thickness of the antiviral adhesive sheet.

In embodiment (2), the grooves are preferably formed across the adhesive layer to facilitate gas escape. Figures 4(a) and (b) show embodiments of groove patterns. The diagonal lines in the figures represent groove patterns. Note that the groove pattern is not limited to the patterns in the embodiments of Figures 4(a) and (b), as long as it allows gas to escape easily.

The width of the groove is not particularly limited, but is preferably 0.05 mm or more and 1 mm or less.
The depth of the groove is not particularly limited, but is preferably 2% to 50% of the thickness of the pressure-sensitive adhesive layer.
The ratio of the area of the grooves to the total area of the adhesive layer is not particularly limited, but is preferably 10% or more and 75% or less.

(3) Porous Adhesive Layer The antiviral adhesive sheet of FIG. 3 has an adhesive layer according to the embodiment (3).
The pressure-sensitive adhesive layer of the third embodiment allows gas to escape through the holes, making it easy to remove bubbles after alignment and shortening the application time. In addition, the pressure-sensitive adhesive layer of the third embodiment can easily increase the haze value of the laminate.

The porous adhesive layer is a layer that is composed of pores and a resin portion formed by the adhesive that forms the adhesive layer.
Pores in the pressure-sensitive adhesive layer may have, for example, the following forms: (i) spherical pores 41 and (ii) concave openings 42, as shown in Fig. 3. The pores in Fig. 3 are a combination of (i) spherical pores 41 and (ii) concave openings 42. The (ii) concave openings 42 are formed on the surface of the pressure-sensitive adhesive layer, i.e., at the interface between the light-transmitting base layer and the pressure-sensitive adhesive layer, and at the interface between the pressure-sensitive adhesive layer and the separator.
The pressure-sensitive adhesive layer having the above-described configuration is prone to thickness unevenness, but by increasing the haze value of the laminate, thickness unevenness of the pressure-sensitive adhesive layer can be made less visible, making it easier to improve the appearance.

The porous pressure-sensitive adhesive layer can be formed, for example, from a pressure-sensitive adhesive resin composition containing bubbles.
When the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive resin composition containing bubbles, the (i) spherical voids are formed when the bubbles remain as voids, and the (ii) concave openings are formed when the bubbles present on one surface of the pressure-sensitive adhesive layer and its vicinity, and on the other surface of the pressure-sensitive adhesive layer and its vicinity, burst. In Fig. 3, the surface of one side of the pressure-sensitive adhesive layer and its vicinity means the interface between the light-transmitting substrate layer 20 and the pressure-sensitive adhesive layer 40 and its vicinity. In Fig. 3, the surface of the other side of the pressure-sensitive adhesive layer and its vicinity means the interface between the pressure-sensitive adhesive layer 40 and the separator 50 and its vicinity.
In the pressure-sensitive adhesive sheet of the present disclosure, the pores preferably have the above-mentioned (ii) concave openings, which can more easily prevent air bubbles from being mixed in when the antiviral pressure-sensitive adhesive sheet is attached.

(ii) It is preferable that the recessed openings are evenly distributed on the surface of the pressure-sensitive adhesive layer facing the light-transmitting base layer and on the other surface of the pressure-sensitive adhesive layer. Having recessed openings evenly distributed on both surfaces can more easily prevent air bubbles from being mixed in when the antiviral pressure-sensitive adhesive sheet is attached. Furthermore, having recessed openings evenly distributed on both surfaces can make thickness variations in the porous pressure-sensitive adhesive layer less noticeable.

Regarding the above (ii) that the recessed openings are evenly distributed, more specifically, it is preferable that the following conditions are satisfied.
When the average diameter of the recessed openings present on the surface of the pressure-sensitive adhesive layer facing the light-transmitting base layer is defined as D ^ave ₁ and the average diameter of the recessed openings present on the surface of the pressure-sensitive adhesive layer facing the other side is defined as D ^ave ₂ , it is preferable that the following condition (1) is satisfied:
|D ^ave ₁ - D ^ave ₂ |/D ^ave ₂ ≦0.5 (1)
Regarding the condition (1), it is more preferable that |D ^ave ₁ - D ^ave ₂ |/D ^ave ₂ ≦0.25, and even more preferable that |D ^ave ₁ - D ^ave ₂ |/D ^ave ₂ ≦0.15.

When the pores in the pressure-sensitive adhesive layer have the above-mentioned (i) spherical pores, the average diameter D ^ave ₃ of the spherical pores preferably satisfies the following condition (2).
D ^ave ₁ ≦ D ^ave ₃ ≦ D ^ave ₂ or D ^ave ₂ ≦ D ^ave ₃ ≦ D ^ave ₁ (2)

Regarding the above conditions (1) and (2), it is practically impossible to determine the average diameters D ^ave ₁ , D ^ave ₂ , and D ^ave ₃ of the openings and the like for all concave openings and spherical holes. Therefore, in this specification, within an observation range of 1500 μm × 1100 μm, diameters are measured at three locations in descending order of diameter, namely, the largest concave openings and the largest spherical holes, and the average value is used as the average diameter of each opening.

When the (ii) concave openings among the pores in the pressure-sensitive adhesive layer satisfy condition (1), the physical properties of the pressure-sensitive adhesive layer can be made more uniform, which makes it easier to achieve more uniform adhesiveness over the entire surface of the pressure-sensitive adhesive layer, thereby facilitating better workability when attaching the antiviral pressure-sensitive adhesive sheet to an article.
Furthermore, among the pores in the pressure-sensitive adhesive layer, (i) spherical pores satisfying condition (2) also make the physical properties of the pressure-sensitive adhesive layer more uniform, as with condition (1), and therefore facilitate improved workability when attaching the antiviral pressure-sensitive adhesive sheet to an article.

There are no particular restrictions on the average diameter of the (i) spherical pores and (ii) concave openings as long as they satisfy the above conditions (1) and (2). While it is difficult to generalize because it varies depending on the thickness of the adhesive layer, it is typically between 1 μm and 300 μm. Considering improved workability, the lower limit is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, while the upper limit is preferably 250 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less.

In consideration of improving workability, the density of the porous pressure-sensitive adhesive layer is preferably 0.1 g/ ^cm3 or more as a lower limit, more preferably 0.2 g/ ^cm3 or more, and even more preferably 0.3 g/ ^cm3 or more as an upper limit, and is preferably 0.8 g/ ^cm3 or less, more preferably 0.7 g/ ^cm3 or less, and even more preferably 0.6 g/ ^cm3 or less as an upper limit.

The adhesion amount of the porous pressure-sensitive adhesive layer is preferably 13 g/m or ^more and 70 g/m ^or less, more preferably 15 g/m or ^more and 60 g/m or ^less , and even more preferably 20 g/m or ^more and 50 g/m or ^less . In this specification, the adhesion amount of the pressure-sensitive adhesive layer means the adhesion amount of the solid content.
By setting the adhesion amount of the porous pressure-sensitive adhesive layer to 13 g/ ^m2 or more, it is possible to easily increase the haze value of the laminate and also to easily improve adhesion to the article. Furthermore, by setting the adhesion amount of the pressure-sensitive adhesive layer to 13 g/ ^m2 or more, it is possible to easily form the recessed openings described above in (ii).
By setting the adhesion amount of the porous pressure-sensitive adhesive layer to 70 g/ ^m2 or less, it is possible to easily suppress a decrease in workability due to an increase in the total thickness of the antiviral pressure-sensitive adhesive sheet.

-Adhesive resin composition-
The resin composition used to form the pressure-sensitive adhesive layer (sometimes referred to herein as an "adhesive resin composition") preferably contains, for example, a resin having adhesive properties, and further contains a salt, a solvent, and an additive as necessary. For a porous pressure-sensitive adhesive layer, an adhesive resin composition containing bubbles is preferred.

Examples of adhesive resins include various rubber-based resins such as urethane rubber, styrene butadiene polymer (styrene butadiene rubber), polyisoprene, natural rubber, acrylonitrile butadiene rubber, ethylene propylene rubber (EPR), ethylene propylene diene terpolymer rubber (EPDM), polynorbornene, polybutadiene, nitrile rubber, chloroprene rubber, butyl rubber, halogenated butyl rubber, ethylene-vinyl acetate rubber (EVA), silicone rubber, fluororubber, ethylene acrylic rubber, polyester elastomer, epichlorohydrin rubber, and polysulfide rubber; various adhesive resins such as acrylic polymer, polyurethane, chlorinated polyethylene, polyethylene, polystyrene, polyimide, polyvinyl chloride, and polypropylene; and various thermoplastic elastomers such as polyolefin, polyurethane, polyester, polyamide, and polystyrene. Resin compositions containing these resins may be cured products of the resin compositions. The cured products of the resin compositions may be one-component cured products or two-component cured products.
Among these resins, acrylic resins with good weather resistance are preferred. That is, the pressure-sensitive adhesive layer preferably contains an acrylic resin composition, more preferably a cured product of the acrylic resin composition. The cured product of the acrylic resin composition may be a one-component cured product or a two-component cured product.

The weight-average molecular weight of the adhesive resin is preferably 250,000 or more, more preferably 260,000 or more, and even more preferably 270,000 or more, and is preferably 12,000,000 or less, more preferably 10,000,000 or less, and even more preferably 8,000,000 or less as the lower limit. When the weight-average molecular weight of the resin is within the above range, it is easy to obtain appropriate adhesion. Furthermore, when the weight-average molecular weight of the resin is within the above range, it is easy to form a porous adhesive layer.
The weight average molecular weight in this specification is an average molecular weight measured by GPC analysis and converted into standard polystyrene.

As the salt, various salts such as inorganic salts and organic salts can be used.
Preferred examples of inorganic salts include sulfates, sulfites, carbonates, hydrogencarbonates, nitrates, nitrites, chlorates, hypochlorites, chlorites, perchlorates, permanganates, chromates, phosphates, hydrogenphosphates, chlorides, bromides, and iodides of metals such as sodium, magnesium, aluminum, potassium, calcium, iron, nickel, copper, zinc, silver, lead, tin, and barium; and also ammonium sulfate, ammonium carbonate, ammonium hydrogencarbonate, ammonium nitrate, ammonium chloride, and potassium aluminum sulfate (alum).

Examples of organic salts include salts of carboxylic acids having 1 to 18 carbon atoms, such as formates, acetates, propanoates, butanoates, and pentanoates, of metals such as sodium, magnesium, aluminum, potassium, calcium, iron, nickel, copper, zinc, silver, lead, tin, and barium; and ammonium salts of carboxylic acids having 1 to 18 carbon atoms.
In addition to the above, examples of the organic salt include ammonium-based, pyridinium-based, imidazolium-based, pyrrolidinium-based, choline-based, phosphonium-based, sulfonium-based, and pyrazolium-based ionic liquids.

In the adhesive resin composition, the salt content per 100 parts by mass of the adhesive resin is preferably 1 part by mass or more, more preferably 1.3 parts by mass or more, even more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and particularly preferably 6.0 parts by mass or more, and the upper limit is preferably 80 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less.

The adhesive composition may contain a solvent in consideration of ease of application, that is, ease of forming an adhesive layer.
The solvent may be either water or an organic solvent.

The solvent content in the adhesive resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and even more preferably 40% by mass or more, relative to the total amount of the adhesive resin and solvent, and the upper limit is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less.

Other additives can be appropriately selected and used depending on the desired performance, and examples thereof include surfactants, foam stabilizers, foaming agents (foaming agents), foaming aids, foam stabilizers, antifoam agents (foam suppressors, foam breakers), emulsifiers, dispersants, wetting agents, propellants, thickeners, curing agents, crosslinking agents, polymerization initiators, colorants (pigments, dyes), plasticizers, adhesives, fillers, antifouling agents, viscoelasticity modifiers, rust inhibitors, slip agents, driers, stabilizers, ultraviolet absorbers, antibacterial agents, antifungal agents, and flame retardants.
When a porous adhesive layer is to be formed, it is preferable to use a surfactant, a foam stabilizer, a foaming agent (foaming agent), a foaming assistant, or a foam stabilizer so that the adhesive resin composition can easily contain bubbles.

The content of other additives can be set appropriately depending on the desired performance and is not particularly limited, but is preferably at least 0.1 parts by mass, more preferably at least 0.5 parts by mass, relative to 100 parts by mass of the adhesive resin, and the upper limit is preferably no more than 10 parts by mass, more preferably no more than 8.5 parts by mass, even more preferably no more than 5 parts by mass, and even more preferably no more than 1.9 parts by mass.

As described above, the adhesive resin composition for forming the porous adhesive layer is preferably an adhesive resin composition containing bubbles. The method for obtaining a composition containing bubbles is not particularly limited, but can be, for example, as follows.
First, the adhesive resin and solvent are used to prepare a form such as a colloid, suspension, sol, or emulsion, and then a salt and, if necessary, additives are added to prepare a stock solution. By stirring the stock solution while supplying nitrogen gas, bubbles can be incorporated into the stock solution, and an adhesive resin composition containing bubbles can be prepared.

When supplying nitrogen gas, the density of the bubble-containing adhesive resin composition can be adjusted by adjusting the amount of nitrogen gas supplied. Furthermore, adjusting the density of the bubble-containing adhesive resin composition makes it easier for the adhesive layer formed using this to satisfy the above-mentioned pore shape, density, etc.

The density of the adhesive resin composition containing bubbles is preferably 0.1 g/ ^cm3 or more, more preferably 0.2 g/ ^cm3 or more, and even more preferably 0.3 g/ ^cm3 or more, and the upper limit is preferably 0.8 g/ ^cm3 or less, more preferably 0.7 g/ ^cm3 or less, and even more preferably 0.6 g/ ^cm3 or less.

The pressure-sensitive adhesive layer may contain additives such as light stabilizers and UV absorbers.

<Primer layer>
The antiviral pressure-sensitive adhesive sheet may have a primer layer to improve interlayer adhesion. The primer layer can be formed, for example, between the light-transmitting substrate layer and the surface protective layer.

The primer layer preferably contains a binder resin.
Examples of binder resins include one or more selected from urethane resins, acrylic polyol resins, acrylic resins, ester resins, amide resins, butyral resins, styrene resins, urethane-acrylic copolymers, polycarbonate-based urethane-acrylic copolymers (urethane-acrylic copolymers derived from polymers having a carbonate bond in the polymer main chain and two or more hydroxyl groups), vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-vinyl acetate-acrylic copolymer resins, chlorinated propylene resins, nitrocellulose resins, and cellulose acetate resins. The binder resin may be a resin obtained by crosslinking and curing the above-mentioned resins with a curing agent such as an isocyanate-based curing agent or an epoxy-based curing agent. Among these, a polyol-based resin such as an acrylic polyol resin crosslinked and cured with an isocyanate-based curing agent is preferred, and an acrylic polyol resin crosslinked and cured with an isocyanate-based curing agent is more preferred.

The primer layer preferably contains an ultraviolet absorber and/or a light stabilizer to further improve weather resistance. General-purpose ultraviolet absorbers and light stabilizers can be used.

The thickness of the primer layer is preferably 0.01 μm or more and 10 μm or less, more preferably 0.7 μm or more and 8 μm or less, and even more preferably 1.0 μm or more and 6 μm or less.

Among the layers constituting the laminate, a laminate obtained by laminating layers other than the pressure-sensitive adhesive layer preferably has an internal haze value of 50% or more, more preferably 60% or more. When the pressure-sensitive adhesive layer is a porous layer, by setting the internal haze value within the above range, thickness unevenness of the porous pressure-sensitive adhesive layer can be made less visible.
In order to improve the visibility of the article, the internal haze is preferably 80% or less, and more preferably 70% or less.
The internal haze value can be measured by, for example, laminating a transparent substrate on the front and back surfaces of a laminate obtained by laminating layers other than the pressure-sensitive adhesive layer among the layers constituting the laminate, thereby filling in the surface irregularities on the front and back surfaces.

<Separator>
The antiviral adhesive sheet preferably has a separator on the laminate, with the adhesive layer and the separator being in contact with each other. By having the separator in the antiviral adhesive sheet, the handleability of the antiviral adhesive sheet can be improved.

The material of the separator is not particularly limited, but may be a plastic film such as polyethylene terephthalate, paper, or nonwoven fabric.
The thickness of the separator is preferably 10 μm or more and 200 μm or less, and more preferably 50 μm or more and 150 μm or less. When the thickness of the separator is in this range, workability when peeling off the separator can be improved.
The separator may have a surface that has been subjected to a release treatment with a release agent such as a silicone-based release agent.

The antiviral adhesive sheet of the present disclosure may have a protective film with low adhesiveness on the surface protective layer opposite the light-transmitting base layer. The protective film serves to protect the surface protective layer during the distribution process of the antiviral adhesive sheet. The protective film is peeled off from the surface protective layer before and after the antiviral adhesive sheet is attached to an article.

<Application>
Applications of the antiviral pressure-sensitive adhesive sheet of the present disclosure include the following (1) to (12):
(1) Surface materials for interior walls, floors, ceilings, etc. of buildings such as houses, offices, stores, hospitals, and clinics.
(2) Surface materials for exterior parts such as exterior walls, roofs, eaves ceilings, door pockets, etc. of buildings such as houses, offices, stores, hospitals, and clinics.
(3) Surface materials (interior or exterior parts) of building fixtures such as windows, window frames, doors, and door frames; surface materials of fixture accessories (handles, etc.); surface materials of building fixture jigs.
(4) Surface materials for construction components such as handrails, waist walls, moldings, thresholds, lintels, and top boards.
(5) Surface materials for outdoor (exterior) parts such as fences, gates, drying rack pillars and handrails.
(6) Surface materials for furniture such as chests of drawers, desks, chairs, cupboards, kitchen sinks, etc.; surface materials for furniture accessories (handles, etc.); surface materials for furniture fixtures.
(7) Surface materials for the housings of various home appliances such as television receivers, radio receivers, refrigerators, microwave ovens, washing machines, electric fans, and air conditioners; surface materials for accessories of home appliances (handles, switches, touch panels, etc.); surface materials for fixtures of home appliances.
(8) Surface materials for office equipment such as various computing devices such as electronic copiers, facsimiles, printers, and personal computers; surface materials for the housings of various office equipment such as ATM devices at financial institutions such as banks and post offices; surface materials for accessories of various office equipment (keyboards, touch panels, etc.); surface materials for jigs of various office equipment.
(9) Surface materials for the interior or exterior parts (walls, floors, ceilings, handrails, supports, control panels, levers, handles, steering wheels, and other control equipment) of vehicles such as automobiles, railway cars, ships, and aircraft.
(10) Partitions in various buildings; shielding plates or curtains to prevent droplet infection of viruses at counters of stores, offices, government offices, etc., accounting settlement locations, etc.; face protection equipment such as protective masks (face guards) and protective glasses (goggles); or surface materials thereof.
(11) Business forms such as slips; bankbooks; cards such as cash cards, credit cards, and point cards of financial institutions; or the surface materials thereof.
(12) Glass, resin, etc. bottles; metal cans; resin soft packaging materials such as resin retort containers; packaging materials such as various tubes; or surface materials thereof.

[Article with antiviral adhesive sheet]
An article with an antiviral adhesive sheet according to the present disclosure is formed by attaching the above-described antiviral adhesive sheet according to the present disclosure onto an article.

Examples of the article include the articles exemplified for use with the antiviral adhesive sheet.
An article with an antiviral adhesive sheet according to the present disclosure preferably contains a resin. Articles containing a resin may release gas over time. The antiviral adhesive sheet constituting the article with an antiviral adhesive sheet according to the present disclosure has a light-transmitting substrate layer made of a polypropylene resin substrate, and therefore has good gas permeability. Therefore, even if gas is generated from the article over time, accumulation of air bubbles between the article and the antiviral adhesive sheet can be suppressed, making it easier to suppress deterioration of the design of the article.

The present disclosure provides, for example, the following [1] to [12].
[1] An antiviral pressure-sensitive adhesive sheet comprising a laminate having, in this order, a surface protective layer containing a binder component and an antiviral agent, a light-transmitting base layer, and a pressure-sensitive adhesive layer,
the light-transmitting substrate layer contains a polypropylene-based resin substrate,
An antiviral adhesive sheet, wherein the antiviral agent is an organic antiviral agent.
[2] The antiviral pressure-sensitive adhesive sheet according to [1], wherein the content of the antiviral agent per 100 parts by mass of the binder component is 0.5 parts by mass or more and 20.0 parts by mass or less.
[3] The antiviral adhesive sheet according to [1] or [2], wherein the average particle size of the antiviral agent is 1 μm or more and 10 μm or less.
[4] The antiviral pressure-sensitive adhesive sheet according to any one of [1] to [3], wherein the organic antiviral agent is one or more selected from the following (1) to (3):
(1) An antiviral agent containing an imidazole compound. (2) An antiviral agent containing a styrene polymer derivative compound and an unsaturated carboxylic acid derivative compound. (3) An antiviral agent containing a styrene resin. [5] The antiviral pressure-sensitive adhesive sheet according to any one of [1] to [4], wherein the polypropylene resin substrate has a thickness of 5 μm or more and 250 μm or less.
[6] The antiviral pressure-sensitive adhesive sheet according to any one of [1] to [5], wherein the pressure-sensitive adhesive layer has a substantially flat surface opposite to the light-transmitting base layer.
[7] The antiviral pressure-sensitive adhesive sheet according to any one of [1] to [5], wherein the pressure-sensitive adhesive layer has a groove on the surface opposite to the light-transmitting base layer.
[8] The antiviral adhesive sheet according to any one of [1] to [5], wherein the adhesive layer is a porous layer.
[9] The antiviral pressure-sensitive adhesive sheet according to any one of [1] to [8], wherein the laminate has a total light transmittance of 80% or more as measured in accordance with JIS K7361-1:1997.
[10] The antiviral pressure-sensitive adhesive sheet according to any one of [1] to [9], which has a separator on the laminate, and the pressure-sensitive adhesive layer and the separator are in contact with each other.
[11] An article with an antiviral adhesive sheet, comprising the antiviral adhesive sheet according to any one of [1] to [10] attached to an article.
[12] The article with the antiviral adhesive sheet according to [11], wherein the article contains a resin.

Next, the present disclosure will be explained in more detail using examples, but the present disclosure is not limited to these examples in any way.

1. Evaluation The following measurements and evaluations were carried out on the antiviral pressure-sensitive adhesive sheets of the Examples and Comparative Examples. The measurements and evaluations were carried out in an atmosphere with a temperature of 23°C ± 5°C and a relative humidity of 40% to 65%. The results are shown in Table 1.

1-1. Suppression of bubbles due to outgassing from the substrate The separator was peeled off from the antiviral adhesive sheets of the Examples and Comparative Examples, and the sheets were attached to a 2 mm thick transparent acrylic plate (50 mm long x 50 mm wide) to obtain an article with an antiviral adhesive sheet. The articles with the antiviral adhesive sheet were left in a 60°C environment for 48 hours, and then visually evaluated by a healthy person in their 30s in a bright room environment according to the following criteria.
A: No air bubbles were observed between the acrylic plate and the adhesive layer.
C: Air bubbles are observed between the acrylic plate and the adhesive layer.

1-2. Discoloration over time The total light transmittance of the antiviral adhesive sheets of the Examples and Comparative Examples was measured immediately after production. The measurement was performed in an atmosphere with a temperature of 23°C ± 5°C and a relative humidity of 40% to 65%. A direct-reading haze meter manufactured by Toyo Seiki Seisakusho was used as the measuring device.
Next, the antiviral adhesive sheets of the examples and comparative examples were left in an environment of 40°C and 90% relative humidity for one week, and then the total light transmittance was measured. When the antiviral adhesive sheet discolors, the transmittance at specific wavelengths decreases, and therefore the total light transmittance also decreases. Therefore, discoloration over time can be evaluated based on the total light transmittance.
The difference between the measured value immediately after production and the measured value after leaving for one week was rated as "A" if it was 0% or more but less than 0.5%, "B" if the difference was 0.5% or more but less than 1%, and "C" if the difference was 1% or more.

The separator was peeled off from the antiviral adhesive sheets of the Examples and Comparative Examples, and the sheets were attached to a wood grain pattern decorative sheet, taking care not to mix in any large air bubbles. Immediately after attachment, a healthy person in their 30s visually evaluated the visibility of the sheet in a bright room according to the following criteria.
A: The wood grain pattern is clearly visible.
B: The wood grain pattern is slightly blurred but still visible.
C: The wood grain pattern is barely visible.

1-4. Adhesion The separator was peeled off from the antiviral adhesive sheets of the Examples and Comparative Examples and attached to a 40 mm diameter vinyl chloride rod to obtain an article with an antiviral adhesive sheet. The articles with the antiviral adhesive sheet were left in an environment of 23°C ± 5°C and a relative humidity of 40% to 65% for 48 hours, and then visually evaluated in a bright room by a healthy person in their 30s according to the following criteria.
A: The stick and the antiviral adhesive sheet are in good contact with each other.
C: Part of the antiviral adhesive sheet is floating from the stick.

1-5. Haze Value and Total Light Transmittance The haze value and total light transmittance of the laminate constituting the antiviral pressure-sensitive adhesive sheet of each of the Examples and Comparative Examples were measured using a direct-reading haze meter manufactured by Toyo Seiki Seisakusho, Ltd.

1-6. Antiviral Activity Value The antiviral activity value of the antiviral pressure-sensitive adhesive sheets of the examples was measured according to the "Method for measuring antiviral activity value" in the main specification. The antiviral activity value was measured against influenza virus. Antiviral activity values of 2 or more were rated "A," and antiviral activity values of less than 2 were rated "C."

2. Preparation of Materials An ink for a surface protective layer and a composition for a pressure-sensitive adhesive layer having the following compositions were prepared.
<Ink 1 for surface protective layer>
70 parts by mass of multifunctional urethane acrylate oligomer; 30 parts by mass of bifunctional urethane acrylate oligomer; 3 parts by mass of antiviral agent (antiviral agent containing particles A1 and A2 below in a mass ratio of 1:1, average particle diameter 5 μm)
(Particles A1: particles containing a styrene polymer derivative compound, a polystyrene sulfonic acid derivative manufactured by Shima Trading Co., Ltd., product name "VERSA-TL3")
(Particles A2: particles containing an unsaturated carboxylic acid derivative compound, particles formed by drying a solvent-based unsaturated polycarboxylic acid polymer manufactured by BYK under the trade name "BYK-P104")
Solvent (ethyl acetate) 40 parts by mass

<Ink for surface protective layer 2>
- 70 parts by mass of multifunctional urethane acrylate oligomer - 30 parts by mass of bifunctional urethane acrylate oligomer - 3 parts by mass of antiviral agent (an inorganic antiviral agent containing silver ions in a carrier, product number "PG711" manufactured by Koa Glass Co., Ltd., the carrier is glass, average particle size 3 μm)
Solvent (ethyl acetate) 40 parts by mass

<Adhesive resin composition 1>
Acrylic adhesive (product name "RC-910W" manufactured by Nichiei Shinka Co., Ltd.)

<Adhesive resin composition 2>
Acrylic adhesive (product name "RC-915" manufactured by Nichiei Shinka Co., Ltd.)

<Preparation of Adhesive Resin Composition 3 (Adhesive Resin Composition Containing Bubbles)>
An acrylic one-component curing adhesive (trade name "Powertight WQ-1000" manufactured by Kansai Paint Co., Ltd.) was stirred with a stirrer to prepare a bubble-containing adhesive resin composition. The density of the resulting bubble-containing adhesive resin composition was 0.4 g/ ^cm3 .

3. Preparation of antiviral adhesive sheet [Example 1]
The ink 1 for surface protection layer was applied by roll coating to one side of a light-transmitting substrate layer (a substrate layer having a particle-containing resin layer on one side of an 80 μm-thick polypropylene resin substrate) and dried at 60° C. for 1 minute. Thereafter, the resin component was cured by irradiating with an electron beam (acceleration voltage: 175 kV, 5 Mrad (50 kGy)) to form a surface protection layer with a thickness of 10 μm.
Next, the adhesive resin composition 1 was applied to the surface of the light-transmitting base layer opposite to the surface on which the surface protective layer was formed, and dried to form a 20 μm-thick adhesive layer. In this way, a laminate having the surface protective layer, the light-transmitting base layer, and the adhesive layer in this order was obtained.
Next, a separator (a 75 μm-thick polyethylene terephthalate film) was laminated onto the surface of the laminate facing the pressure-sensitive adhesive layer, thereby obtaining the antiviral pressure-sensitive adhesive sheet of Example 1. In the antiviral pressure-sensitive adhesive sheet of Example 1, the surface of the pressure-sensitive adhesive layer opposite the light-transmitting base layer is substantially flat.

[Example 2]
A surface protective layer was formed in the same manner as in Example 1 using the same light-transmitting substrate layer as in Example 1.
Next, adhesive resin composition 2 was applied to the surface of the light-transmitting base layer opposite to the surface on which the surface protective layer was formed, and dried to form a 35 μm-thick adhesive layer. In this way, a laminate having the surface protective layer, the light-transmitting base layer, and the adhesive layer in this order was obtained.
Next, a paper separator having convex portions on its surface was laminated onto the surface of the laminate facing the pressure-sensitive adhesive layer, thereby obtaining an antiviral pressure-sensitive adhesive sheet of Example 2. The antiviral pressure-sensitive adhesive sheet of Example 2 has grooves on the surface of the pressure-sensitive adhesive layer opposite the light-transmitting base layer.

[Example 3]
A surface protective layer was formed in the same manner as in Example 1 using the same light-transmitting substrate layer as in Example 1.
Next, adhesive resin composition 3 containing bubbles was applied to the surface of the light-transmitting base layer opposite to the surface on which the surface protective layer was formed, and dried at 100°C for 2 minutes to form a porous adhesive layer. The adhesion amount of the adhesive layer after drying was 30 g/ ^m2 . The density of the formed adhesive layer was 0.4 g/ ^cm3 . In this way, a laminate having a surface protective layer, a light-transmitting base layer, and an adhesive layer in this order was obtained.
Next, a separator (a polyethylene terephthalate film with a thickness of 75 μm) was laminated onto the surface of the laminate facing the pressure-sensitive adhesive layer, thereby obtaining an antiviral pressure-sensitive adhesive sheet of Example 3. In the antiviral pressure-sensitive adhesive sheet of Example 3, the pressure-sensitive adhesive layer is a porous layer.

[Comparative Example 1]
An antiviral pressure-sensitive adhesive sheet of Comparative Example 1 was obtained in the same manner as in Example 1, except that the light-transmitting base material layer was changed to the light-transmitting base material layer described below, and the ink 1 for surface protective layer was changed to the ink 2 for surface protective layer.
Light-transmitting substrate layer of Comparative Example 1: a single layer of polyethylene terephthalate substrate having a thickness of 75 μm.

[Comparative Example 2]
An antiviral adhesive sheet of Comparative Example 2 was obtained in the same manner as in Example 2, except that the light-transmitting base material layer was changed to the light-transmitting base material layer used in Comparative Example 1 and the ink 1 for surface protective layer was changed to the ink 2 for surface protective layer.

[Comparative Example 3]
An antiviral pressure-sensitive adhesive sheet of Comparative Example 3 was obtained in the same manner as in Example 2, except that the light-transmitting base layer was changed to the light-transmitting base layer used in Comparative Example 1.

[Comparative Example 4]
An antiviral pressure-sensitive adhesive sheet of Comparative Example 4 was obtained in the same manner as in Example 1, except that the ink 1 for surface protective layer was changed to the ink 2 for surface protective layer.

As shown in Table 1, the antiviral adhesive sheets of Examples 1 to 3 did not show any bubbles due to outgassing and were able to suppress discoloration over time, confirming that they were able to suppress a decline in the design of the article. Furthermore, it was confirmed that the antiviral adhesive sheets of Examples 1 to 3 had stable adhesion to the article.

10: Laminate 20: Light-transmitting substrate layer 30: Surface protective layer 31: Binder component 32: Antiviral agent 40: Pressure-sensitive adhesive layer 41: Pores (spherical pores)
42: Pore (concave opening)
50: Separator 100: Antiviral adhesive sheet

Claims (9)

An antiviral pressure-sensitive adhesive sheet comprising a laminate having, in this order, a surface protective layer containing a binder component and an antiviral agent, a light-transmitting base layer, and a pressure-sensitive adhesive layer,
the light-transmitting substrate layer contains a polypropylene-based resin substrate,
the pressure-sensitive adhesive layer is a porous layer,
An antiviral adhesive sheet, wherein the antiviral agent is an organic antiviral agent. The antiviral adhesive sheet according to claim 1, wherein the content of the antiviral agent per 100 parts by mass of the binder component is 0.5 parts by mass or more and 20.0 parts by mass or less. The antiviral adhesive sheet according to claim 1 or 2, wherein the average particle size of the antiviral agent is 1 μm or more and 10 μm or less. The antiviral pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the organic antiviral agent is one or more selected from the following (1) to (3):
(1) Antiviral agents containing imidazole compounds (2) Antiviral agents containing styrene polymer derivative compounds and unsaturated carboxylic acid derivative compounds (3) Antiviral agents containing styrene resins The antiviral adhesive sheet according to any one of claims 1 to 4, wherein the polypropylene resin substrate has a thickness of 5 μm or more and 250 μm or less. The antiviral pressure-sensitive adhesive sheet according to any one of claims 1 to 5 , wherein the laminate has a total light transmittance of 80% or more as measured in accordance with JIS K7361-1:1997. The antiviral pressure-sensitive adhesive sheet according to any one of claims 1 to 6 , further comprising a separator on the laminate, the pressure-sensitive adhesive layer being in contact with the separator. An article with an antiviral adhesive sheet, comprising the antiviral adhesive sheet according to any one of claims 1 to 7 attached to the article. The article with the antiviral adhesive sheet according to claim 8 , wherein the article contains a resin.