JP7725929B2 - Antiviral hardened material - Google Patents

Description

The present invention relates to a cured product that can exhibit antiviral properties.

In light of the recent COVID-19 pandemic and other factors, technological developments are being attempted to improve the hygiene of various products, components, and commercial materials surrounding our living environments. For example, JP 2020-510734 A (Patent Document 1) reports a photocurable polymer film that exhibits antibacterial properties when irradiated with light in the visible light range. Specifically, it reports that a coating composition (see Claim 1, etc.) containing a (meth)acrylate monomer or oligomer containing an alkylene oxide having 1 to 10 carbon atoms, a photosensitizer, and a photoinitiator is applied to a substrate, followed by photocuring to produce a polymer film (see paragraphs 0044, 0047, 0091, etc.). When the polymer film is irradiated with light in the visible light range, the photosensitizer absorbs the visible light, generating active oxygen species or free radicals, thereby imparting antibacterial properties to the film (paragraphs 0004, 0030, Table 1, etc.).

Special Publication No. 2020-510734

The present inventors have now discovered a novel configuration capable of exhibiting antiviral properties. Specifically, they confirmed that good antiviral properties can be obtained by irradiating a cured product of a composition containing a certain polymerizable monomer or oligomer with ultraviolet light having a wavelength of 350 nm or less. Specifically, they discovered that there are chemical species that generate radicals when the cured product is irradiated with ultraviolet light having a wavelength of 350 nm or less at a light intensity of 0.15 mW/ ^cm2 or more, and that the radicals generated by these chemical species exhibit good antiviral properties. Furthermore, they identified a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups contained in the composition as the radical-generating chemical species present in the cured product. The present invention is based on these findings.

Therefore, the object of the present invention is to provide a cured product that can exhibit good antiviral properties.

The antiviral cured product according to the present invention is
The cured product is a composition containing a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups, and is characterized in that it exhibits antiviral properties when used by irradiating it with ultraviolet light having a wavelength of 350 nm or less at a light receiving amount of 0.15 mW/ ^cm2 or more.

The present invention provides a cured product that exhibits excellent antiviral properties.

Cured Product According to the Present Invention: A cured product capable of exhibiting antiviral properties according to the present invention (hereinafter sometimes referred to as an "antiviral cured product") can exhibit antiviral properties when irradiated with ultraviolet light having a wavelength of 350 nm or less. The antiviral cured product according to the present invention is a cured product of a composition containing a compound that generates radicals when irradiated with ultraviolet light having a wavelength of 350 nm or less, specifically, a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups. The antiviral cured product according to the present invention is a cured product of a composition containing a compound that generates radicals when irradiated with ultraviolet light having a wavelength of 350 nm or less at a light intensity of 0.15 mW/cm2 or ^more , preferably a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups. This cured product is used after exhibiting antiviral properties when irradiated with ultraviolet light having a wavelength of 350 nm or less at a light intensity of 0.15 mW/ ^cm2 or more. In the present invention, "irradiating with ultraviolet light having a wavelength of 350 nm or less at an amount of light received of 0.15 mW/ ^cm2 or more" means that a cured product is irradiated with ultraviolet light having a wavelength of 350 nm or less, and the cured product is exposed to ultraviolet light having a wavelength of 350 nm or less at an amount of light received of ^0.15 mW/cm2 or more. Note that "cured product of the composition" means a product obtained by curing the composition.

In the present invention, the mechanism by which antiviral properties are exhibited is believed to be as follows. Specifically, a cured product of a composition containing a compound that generates radicals upon irradiation with ultraviolet light having a wavelength of 350 nm or less, preferably a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups (hereinafter sometimes referred to as the "cured product of the present invention" or simply the "cured product"), is irradiated with ultraviolet light having a wavelength of 350 nm or less at a light intensity of 0.15 mW/ ^cm2 or more. This generates radicals originating from the polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups, for example, through the formation or dissociation of some of the double bonds in the cured product. The presence of these radicals on the surface of the cured product allows viruses adhering to the surface of the cured product to come into contact with the radicals, which then inactivate the viruses through the oxidative action of the radicals. In this way, the cured product of the present invention is able to exhibit good antiviral properties. Note that the above-described mechanism by which antiviral properties are exhibited is hypothetical, and the present invention is in no way limited by this hypothesis.

In the present invention, the antiviral properties of the cured product of the present invention mean that the antiviral activity value determined by the following test method in accordance with JIS R1756 (2020) in a dark place is 2 or greater.

An antiviral test is carried out in accordance with JIS R1756 (2020) Antiviral Test Method in a Dark Place, and the antiviral activity value (V) in a dark place is calculated using the following formula (1).
Antiviral activity value: V = Log ₁₀ (UV/TV) Formula (1)
TV: bacteriophage infectivity titer (pfu) 24 hours after instillation of bacteriophage solution
UV: Bacteriophage infectivity titer (pfu) immediately after dropping the bacteriophage liquid

The cured product of the present invention can exhibit antiviral properties with an antiviral activity value V, calculated by the above formula (1), of 2 or more. In general, an antiviral activity value V of 2 or more is considered to have good antiviral properties.

In addition, the reduction rate of infectious viruses after 24 hours can also be calculated using the TV and UV in the above formula (1) according to the following formula (2).
Reduction rate (%) = (UV-TV)/UV x 100 Formula (2)
The infectious virus reduction rate calculated by the above formula (2) is also used as an index representing the antiviral properties of the cured product according to the present invention, similar to the antiviral activity value V.

The cured product of the present invention can exhibit antiviral properties with an infectious virus reduction rate of 99% or more, as calculated by (2) above. Generally, a product is evaluated as having good antiviral properties when the infectious virus reduction rate is 99% or more.

In the present invention, "ultraviolet rays with a wavelength of 350 nm or less" includes all ultraviolet rays with a wavelength of 350 nm or less. Therefore, without being limited by the source of the ultraviolet rays, they include ultraviolet rays irradiated from the sun outdoors, ultraviolet rays irradiated from the sun indoors in everyday living environments, and ultraviolet rays irradiated from light sources other than the sun. It is said that sunlight contains approximately 5% ultraviolet rays, and ultraviolet rays with a wavelength of 350 nm or less account for approximately 20% of this ultraviolet light. The ultraviolet rays irradiated from the sun indoors in everyday living environments refer, for example, to ultraviolet rays irradiated from the sun that are transmitted through window glass or the like and irradiated indoors. The received light intensity of ultraviolet rays with a wavelength of 350 nm or less originating from sunlight irradiated indoors is considered to be 0.4 mW/ ^cm2 or more and 1.5 mW/ ^cm2 or less. Light sources other than the sun include low-pressure mercury lamps (germicidal lamps), high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, gallium lamps, metal halide lamps, ultraviolet lasers, deep-ultraviolet LED lamps, etc. In the present invention, the amount of ultraviolet light received by the cured product with a wavelength of 350 nm or less is preferably 0.15 mW/ ^cm2 or more. Here, the amount of ultraviolet light received by the cured product with a wavelength of 350 nm or less means, as already explained, the amount of ultraviolet light received by the cured product with a wavelength of 350 nm or less. The amount of received light is preferably measured using a Hamamatsu Photonics H9958 measuring device. In the present invention, the cumulative amount of received light by irradiation with ultraviolet light with a wavelength of 350 nm or less is preferably 40 mJ/ ^cm2 or more, and more preferably 135 mJ/cm2 or ^more . This enables the development of good antiviral properties. Hereinafter, "ultraviolet light with a wavelength of 350 nm or less" will be referred to as "specific ultraviolet light," and "amount of received light of 0.15 mW/ ^cm2 or more" will also be referred to as "specific amount of received light."

In the present invention, the phrase "used after expressing antiviral properties by irradiating with ultraviolet light having a wavelength of 350 nm or less at a light receiving dose of 0.15 mW/ ^cm2 or more" means the following: Assuming that the antiviral properties exhibited when a cured product according to the present invention is irradiated once (once) with ultraviolet light having a wavelength of 350 nm or less at a specific light receiving dose are finite, this means that a cured product of a composition containing a compound that generates radicals upon irradiation with specific ultraviolet light at a specific light receiving dose, preferably a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups, is irradiated with specific ultraviolet light at a specific light receiving dose as needed, that is, to the extent that antiviral properties are expressed. In other words, irradiation with specific ultraviolet light at a specific light receiving dose is not necessarily required when implementing the present invention. For example, if a cured product that was placed in an environment in the past where it could be irradiated with specific ultraviolet light at a specific light receiving dose (a cured product that was actively or passively irradiated with specific ultraviolet light at a specific light receiving dose) still maintains (sustains) the desired antiviral properties when used, irradiation with specific ultraviolet light at a specific light receiving dose is not necessarily required. On the other hand, in the above examples, if the desired antiviral properties are not maintained or there is a possibility that they will be maintained during use, the cured product can be irradiated with specific ultraviolet light at a specific light-receiving intensity, thereby restoring the antiviral properties. In other words, in the present invention, the need for irradiation with specific ultraviolet light at a specific light-receiving intensity can be determined appropriately, taking into account the environment in which the cured product is placed, the conditions of use, and the time over which the cured product can exhibit antiviral properties (the lifespan of the antiviral properties in the cured product). This is expected to enable the cured product of the present invention to semi-permanently maintain the expression of antiviral properties. Hereinafter, irradiation with specific ultraviolet light at a specific light-receiving intensity may be abbreviated simply as "irradiating specific ultraviolet light" or "irradiating specific ultraviolet light."

Duration of antiviral activity : When irradiated with a specific light receiving intensity of ultraviolet light with a wavelength of 350 nm or less, the antiviral cured product of the present invention can maintain good antiviral activity, with an antiviral activity value V of 2 or more, for about 2 weeks under normal environmental and static conditions.
As described above, in the present invention, whether or not irradiation with ultraviolet light having a wavelength of 350 nm or less at a specific light receiving amount is necessary can be determined appropriately depending on the use and purpose of the cured product according to the present invention. For example, the specific ultraviolet light can be irradiated again to restore the antiviral activity before the antiviral activity is lost after about two weeks. In other words, after one irradiation with specific ultraviolet light, re-irradiation with specific ultraviolet light can be carried out as appropriate within a range in which the desired antiviral activity can be sustained, and irradiation can be carried out, for example, at a frequency of one week. Furthermore, irradiation with specific ultraviolet light can be carried out continuously or intermittently.

Hydrophilicity: The antiviral cured product of the present invention preferably has hydrophilicity. This hydrophilicity can be expressed as an index by the static contact angle with water. The static contact angle with water of the antiviral cured product of the present invention can be measured, for example, using a FACE contact angle meter CA-X150 (manufactured by Kyowa Interface Science Co., Ltd.) by dropping a 2 μL water droplet onto the antiviral cured product at room temperature and measuring the static contact angle after 20 seconds using the θ/2 method. The water contact angle of the antiviral cured product of the present invention is preferably 40 degrees or less. When water adheres to the surface of a cured product having such a water contact angle, a rolling-up effect is achieved, resulting in a surface that is less susceptible to dirt adhesion. Because the antiviral cured product of the present invention also has such hydrophilicity, it is advantageous when applied to the surface of wet-related items.

The antiviral cured product according to the present invention can be applied to the surfaces of various articles. Preferably, it can be applied to the surfaces of wet-related articles that require high hygiene. In the present invention, wet-related articles refer to components used in toilets, bathrooms, kitchens, vanities, etc., and examples include bathroom wall materials, bathroom floor materials, bathroom counters, bathtubs, bathtub rims, bathroom window materials, bathroom door materials, shower booth wall materials, washbasin mirrors, vanities, washbasins, kitchen counters, kitchen doors, storage shelves, storage boards, toilet bowls, toilet seats, warm-water washing toilet seats and their cleaning nozzles, drains, faucets, and range hood materials, but are not limited to these.

The composition of the present invention and the method for producing the cured product thereof will now be described.
composition
In the present invention, the composition contains at least a compound that generates radicals upon irradiation with specific ultraviolet rays. In the present invention, the compound that generates radicals upon irradiation with specific ultraviolet rays is a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups. By including a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups in the composition, radicals can be efficiently generated by irradiation with specific ultraviolet rays on a cured product of the composition, preferably on the surface of the cured product. Furthermore, by including a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups in the composition, durability can be imparted to the cured product of the composition. This durability is advantageous when the antiviral cured product of the present invention is applied to the surface of a wet area.

In the present invention, the composition preferably contains 25% by weight or more and 99.9% by weight or less, and more preferably 40% by weight or more and 99% by weight or less, of a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups. This can further enhance the antiviral properties and durability of the cured product according to the present invention, and can also impart strength to the cured product.

In the present invention, the functional group is preferably an ethylenically unsaturated group. The ethylenically unsaturated group is preferably a vinyl group, an acryloyl group, or a methacryloyl group, and more preferably an acryloyl group or a methacryloyl group. The acryloyl group or methacryloyl group is likely to generate radicals upon irradiation with specific ultraviolet rays, and as a result, the cured product according to the present invention is more likely to exhibit antiviral properties. In this specification, the term (meth)acrylic monomer or oligomer is considered to be synonymous with the term (meth)acrylate monomer or oligomer.

Examples of (meth)acrylic monomers (oligomers) having three or more functional groups include ethoxylated isocyanuric acid triacrylate, ε-caprolactone-modified tris-(2-acryloxyethyl)isocyanurate, pentaerythritol triacrylate, trimethylolpropane triacrylate, ditrimethylolpropane trimethacrylate, ethoxylated glycerin triacrylate, ethoxylated pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, trimethylolpropane triacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polytetramethylene glycol diacrylate, glycerin triacrylate ethoxylate, and dipentaerythritol polyacrylate.

Radical Scavenger Having a Phenol Group In the present invention, the composition preferably further contains a radical scavenger having a phenol group. By including a radical scavenger having a phenol group in the composition, when a cured product of the composition is irradiated with specific ultraviolet light, the scavenger captures radicals generated within the cured product, preferably on the surface of the cured product, and the radicals can be retained on the surface of the cured product. Specifically, when a cured product of the composition is irradiated with specific ultraviolet light, a radical (.) generated in the cured product originating from a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups abstracts the radical scavenger's own phenolic hydrogen (—OH), forming a stable radical (—O.). The presence of the radical scavenger on the surface of the cured product, which has captured the radical and is in a stable state, allows viruses attached to the surface of the cured product to come into contact with the radicals, more reliably inactivating the viruses and maintaining antiviral activity for a long period of time. In this way, when the cured product of the present invention is used after being irradiated with specific ultraviolet rays, it is possible to exhibit better antiviral properties for a long period of time due to the oxidizing action of both radicals that are generated from a radical-generating compound, preferably a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups, and that exist on the surface of the cured product in a mobile state, and radicals that exist on the surface of the cured product in a fixed state after being captured by a radical scavenger.

In the present invention, the radical scavenger having a phenol group is not particularly limited as long as it is a compound with radical scavenging ability. For example, 4-methoxyphenol (MEHQ), 3,6-dihydroxybenzonorbornane, 2,5-bis(1,1,3,3-tetramethylbutyl)hydroquinone, 2,2'-methylenebis(6-cyclohexyl-p-cresol), 4,4'-butylidenebis(6-tert-butyl-m-cresol), hydroquinone, 2,6-di-tert-butyl-p-cresol, tert-butylhydroquinone, 6-tert-butyl-2,4-xylenol, 4-tert-butylpyrocatechol, 2,6-di-tert-butylphenol, etc. can be used.

In the present invention, the composition preferably contains 10 ppm to 10,000 ppm of a radical scavenger having a phenol group. By including 10 ppm or more of a radical scavenger, it is possible to stabilize the radical-generating compound, preferably a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups, thereby making it possible to obtain a cured product with excellent antiviral properties and durability. By including 10,000 ppm or less of a radical scavenger, it is possible to suppress a decrease in the curing reactivity of the composition when irradiated with specific ultraviolet light, and it is also possible to suppress discoloration of the composition and its cured product. Suppressing discoloration of the cured product is advantageous in that it allows the appearance or design of an article to which the cured product of the present invention is applied to its surface to be maintained.

Other ingredients
Compound (a) containing a sulfonic acid group
In the present invention, the cured product of the present invention preferably contains sulfonic acid groups at least on the surface. By containing sulfonic acid groups on the surface of the cured product, the cured product can exhibit hydrophilicity in addition to antiviral properties, as described above. Having hydrophilicity, for example, when the cured product of the present invention is applied to the surface of a wet item, is advantageous in that it improves drainage and drying properties, making it possible to prevent the adhesion of stains such as water stains due to residual water, and further prevents the adhesion of oil. According to a preferred embodiment of the present invention, the cured product of the present invention contains sulfonic acid groups on its surface. According to a more preferred embodiment of the present invention, the cured product of the present invention contains more sulfonic acid groups on the surface than in its interior. In other words, it is preferable that the sulfonic acid groups segregate on the surface of the cured product of the present invention.

As described below, the cured product of the present invention can be obtained as follows. First, a composition is applied to a substrate, and the (wet) coating of the composition applied to the substrate is dried to obtain a (dried) coating. The (dried) coating of the composition is then cured to obtain a cured film of the composition. Herein, the dried (wet) coating, i.e., the (dry) coating, is also referred to as an "uncured film" because it is subsequently cured. As described above, the segregation of sulfonic acid groups on the surface of the cured product of the present invention is believed to be achieved by, but not limited to, the following process. By drying the (wet) coating of the composition, i.e., by volatilizing the solvent and, optionally, the volatile compound (b) (details of which will be described later) contained in the (wet) coating along with compound (a), compound (a), which was uniformly dispersed in the composition, segregates to the surface of the uncured film as the drying (volatilization) progresses, taking advantage of the polarity difference and compatibility with volatile compound (b). This is achieved by curing the uncured film while the drying of the (wet) coating is nearly complete and the segregation of compound (a) to the surface of the uncured film is maximized.

In the present invention, the type of compound that provides sulfonic acid groups to the cured product is not particularly limited, but for example, the composition before curing may contain a compound having a sulfonic acid group. Examples of such compounds include compounds having a sulfonic acid group and at least one ethylenically unsaturated group in the molecule. Specific examples include sodium or potassium salts of 2-((meth)acryloyloxy)ethanesulfonic acid, 3-((meth)acryloyloxy)propane-1-sulfonic acid, and acrylamido-tertiary-butylsulfonic acid. Preferred are linear alkylsulfonic acids having a (meth)acryloyloxy group and their salts, such as 2-((meth)acryloyloxy)ethanesulfonic acid and potassium 3-((meth)acryloyloxy)propane-1-sulfonate (potassium 3-sulfopropyl methacrylate). Additionally, compounds having a sulfonic acid group and at least one ethylenically unsaturated group in the molecule include methacrylic sulfonic acid, sodium or potassium salt of p-styrenesulfonic acid, alkylsulfosuccinic acid alkenyl ether salt, polyoxyethylene (meth)acrylate sulfate ester salt, alkylsulfosuccinic acid alkenyl ester salt, and glycerol-1-allyl-3-alkylphenyl-2-polyoxyethylene sulfate. The above-mentioned sulfonic acid group-containing compound (a) has sufficient reactivity with the polyfunctional (meth)acrylic monomers or oligomers having three or more functional groups described above, and can impart high durability to the cured product of the present invention.

Volatile Compounds (b)
In the present invention, the cured product according to the present invention preferably contains a volatile compound (b) having a smaller molecular weight than the sulfonic acid group-containing compound (a) and having a hydrophilic group in the molecule. Here, the volatile compound refers to a compound having a boiling point of 280°C or less, more preferably 260°C or less. Furthermore, the hydrophilic group in the volatile compound (b) is preferably a hydroxyl group or a carboxyl group. In one embodiment of the present invention, the cured product contains the volatile compound (b), for example, the composition before curing may contain the volatile compound (b). Examples of such volatile compounds (b) include volatile compounds having a smaller molecular weight than the sulfonic acid group-containing compound (a) and having one ethylenically unsaturated group and a hydrophilic group in the molecule. Specific examples include hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate and structural isomers thereof, hydroxybutyl (meth)acrylate and structural isomers thereof, tetrahydrofurfuryl (meth)acrylate, (meth)acryloylmorpholine, N-vinylformamide, (meth)acrylic acid, etc. Among these, hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, and (meth)acrylic acid are preferred as the volatile compound (b) from the viewpoint of compatibility with the compound (a).

The cured product of the present invention can be obtained by applying the composition to a substrate, drying the (wet) coating on the substrate, and curing the uncured film. In this process, it is believed that sufficient compatibility between the sulfonic acid group-containing compound (a) and the volatile compound (b) allows compound (b) to segregate to the surface of the uncured film together with compound (a) when the (wet) coating of the composition is dried by heating, thereby enabling compound (a) to be uniformly distributed on the surface of the uncured film. Furthermore, it is believed that the volatile compound (b) remaining in the uncured film can easily polymerize with the polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups and the sulfonic acid group-containing compound (a) when the uncured film is cured, thereby further increasing the strength of the cured film.

The molecular weight of the volatile compound (b) is not particularly limited as long as it is smaller than the molecular weight of the compound (a), but is preferably 500 or less. When the molecular weight of the volatile compound (b) is 500 or less, the volatile compound (b) can be efficiently volatilized when drying a (wet) coating of the composition. Furthermore, when the volatile compound (b) is volatilized together with the solvent component described below, it is thought that phase separation occurs between the compound (a) containing sulfonic acid groups, which has been compatibilized by the inclusion of the volatile compound (b), and the polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups. It is thought that this phase separation promotes segregation of the compound (a) containing sulfonic acid groups to the surface of the uncured film.
The molecular weight of the volatile compound (b) is more preferably 100 to 200. This allows the compound (b) to volatilize without reducing the strength of the cured product when an uncured film of the composition is cured (polymerized).

In the present invention, the molar ratio of the amount of volatile compound (b) to the sum of the amounts of polyfunctional (meth)acrylic monomers or oligomers having three or more functional groups, compound (a) containing sulfonic acid groups, and volatile compound (b) is preferably greater than 0.5 and less than 0.99. A molar ratio of compound (b) greater than 0.5 can ensure sufficient moisture resistance, while a molar ratio of less than 0.99 increases the compatibility between compound (a) and compound (b), allowing compound (a) to segregate on the surface of the cured product, thereby imparting sufficient hydrophilicity to the cured product.

It is more preferable that the ratio (molar ratio) of the amount of compound (b) is greater than 0.5 and less than 0.8. This prevents a decrease in the durability of the cured product due to an increase in the ratio of compound (b) to the polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups in the composition. The ratio (molar ratio: former/latter) of the amount of compound (b) to the polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups is preferably 1.1 or greater and 2.5 or less. This allows a highly durable cured product to be obtained.

In the present invention, the composition preferably contains a solvent to improve the wettability of the composition to the substrate and to adjust the viscosity of the composition. From the viewpoint of compatibility with other compounds contained in the composition, examples of such solvents include, but are not limited to, alcohols such as methanol, ethanol, IPA (isopropanol), and n-butanol; cellosolves such as methoxyethanol and methoxypropanol; ketones such as acetone; DMF (N,N'-dimethylformamide); and water. A mixture of multiple solvents may be used as needed.

Polymerization Initiator In the present invention, as described below, when an uncured film of the composition is cured (polymerized) by heat, the composition may contain a known radical polymerization initiator, curing catalyst, polymerization accelerator, etc. Furthermore, when an uncured film of the composition is cured (polymerized) by radiation, for example, active energy rays such as ultraviolet rays or visible light, the composition may contain a known photopolymerization initiator. An example of the photopolymerization initiator is Omnirad 500 manufactured by IGM.

Method for Producing the Cured Product of the Present Invention The cured product of the present invention can be produced, for example, as follows.

Preparation of Substrate First, a substrate to which the composition is to be applied is prepared.
In the present invention, the substrate is not particularly limited as long as it is a material to which the composition can be applied. From the viewpoint of the use of the cured product according to the present invention, the substrate is preferably a wet-related component that is used in an environment where it is periodically exposed to water and requires hygiene. Examples of wet-related components include, but are not limited to, bathroom wall materials, bathroom floor materials, bathroom counters, bathtubs, bathtub rims, bathroom window materials, bathroom door materials, shower booth wall materials, washbasin mirrors, vanity units, washbasins, kitchen counters, kitchen doors, storage shelves, storage boards, toilet bowls, toilet seats, warm-water washing toilet seats and their washing nozzles, drains, faucets, and range hood materials.
In terms of materials, the substrate is not particularly limited, and examples thereof include metal, glass, resin, paper, and wood materials. Among these, a resin material is preferable. Examples of the resin material include thermosetting resins and thermoplastic resins. As the thermosetting resin, one or more types selected from urea resin, melamine resin, phenolic resin, unsaturated polyester resin, epoxy resin, and silicone resin can be used. The thermoplastic resin may be one or more selected from polypropylene resin (PP), polyethylene resin (PE), polyacetal resin (POM), polybutylene terephthalate resin (PBT), polyvinyl chloride resin (PVC), polystyrene resin (PS), acrylonitrile-butadiene-styrene copolymer resin (ABS), polyphenylene sulfide resin (PPS), polyethylene terephthalate resin (PET), polymethyl methacrylate resin (PMMA), polyamide resin (PA), polyether ether ketone resin (PEEK), polytrimethylene terephthalate resin (PTT), polycarbonate resin (PC), and polytetrafluoroethylene (PTFE) (tetrafluoroethylene resin). In the present invention, a thermoplastic resin is preferably used as the resin. More preferably, the resin is one or more selected from PP, PE, POM, PBT, PVC, ABS, PPS, PET, PMMA, PA, and PC. Among these, one or more selected from PP, POM, PBT, ABS, and PMMA are even more preferred. When the substrate is an acrylic resin material, the composition to be applied to the substrate contains a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups, and therefore, for example, the substrate made of an acrylic resin material has good affinity (for example, adhesion) with the composition or the coated product thereof.

Coating Step The composition is then coated onto a substrate to form a (wet) coating of the composition.
In the present invention, the composition can be applied to a substrate by any known method, such as brush coating, spray coating, dip coating, spin coating, or curtain coating.

Drying step: Next, the (wet) coating formed on the substrate is dried to obtain an uncured film. At this time, it is sufficient that the (wet) coating can be dried, and if necessary, it may be dried by heating. By (heating) drying, the solvent and volatile compound (b) contained in the (wet) coating are volatilized. In this step, in parallel with the evaporation of the solvent and volatile compound (b) from the (wet) coating (in other words, following the migration of the solvent and volatile compound (b) to the surface of the uncured film), it is thought that the compound (a) that was uniformly dispersed in the (wet) coating before (heating) drying will segregate to the surface of the uncured film by utilizing the polarity difference and compatibility with the volatile compound (b).

The heat drying method can be a known method using infrared rays or hot air, etc. The heating temperature is typically between room temperature and 200°C, preferably between 35°C and 150°C, and more preferably between 40°C and 100°C. The drying time can be determined appropriately within a range that allows the solvent and volatile compound (b) to be sufficiently volatilized, and can be determined depending on the material and size of the member to which the composition is applied. For example, it can be within 30 minutes, preferably within 20 minutes, and more preferably within 15 minutes.

Next, the uncured film is cured by copolymerizing the polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups, the compound (a) containing a sulfonic acid group, and optionally the remaining volatile compound (b).
The curing of the uncured film is preferably carried out while the solvent and volatile compound (b) are sufficiently volatilized by the (heat) drying step and the state in which the compound (a) having sulfonic acid groups is segregated to the surface of the uncured film is maintained to the maximum extent. This is believed to ensure that the cured product of the present invention has sulfonic acid groups segregated to its surface. As a result, the antiviral cured product of the present invention is also believed to be able to exhibit sufficient hydrophilicity.
Even if the volatile compound (b) remains in the uncured film, the compound (b) can easily polymerize with the polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups and the compound (a) containing a sulfonic acid group when the uncured film is cured, and therefore it is thought that the strength of the cured film can be further increased.

The uncured film can be cured using any known method for polymerizing a compound containing an ethylenically unsaturated group, such as heat curing, active energy ray curing, or a combination thereof.

When polymerizing and curing by heat curing, known polymerization initiators can be used. Furthermore, as with the drying process of the (wet) coated material described above, known heating methods such as infrared heating or hot air heating can be used. In the case of heat curing, the drying and curing processes of the (wet) coated material can also be carried out simultaneously in a single process.

When polymerization and curing are performed using actinic radiation, examples of the radiation include visible light of 400 to 800 nm, ultraviolet light of 400 nm or less, and electron beams. However, ultraviolet light is preferred because it allows for simple and rapid polymerization. When curing with ultraviolet light, a known photopolymerization initiator is used. The photopolymerization initiator is added in an amount of 0.01 to 20% by mass, preferably 1 to 10% by mass, of the polymerizable compound contained in the composition. UV sources include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, gallium lamps, metal halide lamps, ultraviolet lasers, deep-ultraviolet LED lamps, and sunlight. The irradiation atmosphere may be air or an inert gas such as nitrogen or argon.

The thickness of the cured product according to the present invention produced as described above may be appropriately determined depending on the intended use and within a range in which the effects of the present invention can be achieved. For example, the thickness is preferably in the range of 0.1 μm to 300 μm, more preferably in the range of 1 to 100 μm, and even more preferably in the range of 1 to 20 μm.
According to a preferred embodiment of the present invention, the cured product according to the present invention is a membrane-like material. In the present invention, the term "membrane-like material" is synonymous with "sheet-like material" or "film-like material."

Between each of the above processes, there may be a transfer process in which the substrate is moved on a belt conveyor or the like, or a waiting process required to move between processes.

Antiviral Member According to one aspect of the present invention, there is provided an antiviral member comprising a substrate and the above-described antiviral cured product formed on the surface of the substrate.

One aspect of the present invention provides a system for expressing or maintaining antiviral activity , comprising the above-described antiviral material and irradiation means capable of irradiating with ultraviolet light having a wavelength of 350 nm or less. In this system, the antiviral activity of the antiviral material can be expressed or maintained by irradiating the antiviral material with ultraviolet light having a wavelength of 350 nm or less.

Irradiation means capable of irradiating ultraviolet rays with wavelengths of 350 nm or less are not particularly limited as long as they are capable of irradiating ultraviolet rays with wavelengths of 350 nm or less. Specifically, the ultraviolet rays irradiated by the above-mentioned irradiation means include ultraviolet rays irradiated from the sun outdoors, ultraviolet rays irradiated from the sun indoors in everyday living environments, and ultraviolet rays irradiated from light sources other than the sun. Irradiation means other than the sun, i.e., light sources other than the sun, include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, gallium lamps, metal halide lamps, ultraviolet lasers, and deep-ultraviolet LED lamps.

Plumbing System According to one aspect of the present invention, there is provided a plumbing system comprising the antiviral expression or maintenance system described above.

The present invention will be specifically explained based on the following examples, but the present invention is not limited to these examples.

Preparation of the composition
Composition 1
Composition 1 was prepared by stirring a solution containing 7 g (12.2 mmol) of dipentaerythritol hexaacrylate containing 500 ppm of 4-methoxyphenol (MEHQ) as a radical scavenger, 0.14 g of Omnirad 500 as a photopolymerization initiator, and 15 g of methoxyethanol as a solvent with a stirrer for 60 minutes.
The photopolymerization initiator Omnirad 500 is a mixture of 1-hydroxycyclohexyl phenyl ketone and benzophenone in a weight ratio of 1:1.

Composition 2
0.08 g (0.32 mmol) of potassium 3-sulfopropyl methacrylate was dissolved in 0.5 g of water, and then 3.5 g (6.1 mmol) of dipentaerythritol hexaacrylate containing 500 ppm of 4-methoxyphenol (MEHQ) as a radical scavenger, 3.5 g (7.7 mmol) of trimethylolpropane triacrylate containing 100 ppm of 4-methoxyphenol (MEHQ) as a radical scavenger, 0.4 g (3.1 mmol) of hydroxymethyl methacrylate, 0.14 g of Omnirad 500 as a photopolymerization initiator, and 15 g of methoxyethanol as a solvent were added, and the mixture was stirred with a stirrer for 60 minutes to prepare Composition 2.

Composition 3
0.08 g (0.32 mmol) of potassium 3-sulfopropyl methacrylate was dissolved in 0.5 g of water, and then 7 g (12.2 mmol) of dipentaerythritol hexaacrylate containing 500 ppm of 4-methoxyphenol (MEHQ) as a radical scavenger, 0.4 g (3.1 mmol) of hydroxymethyl methacrylate, 0.14 g of Omnirad 500 as a photopolymerization initiator, and 15 g of methoxyethanol as a solvent were added, and the mixture was stirred with a stirrer for 60 minutes to prepare Composition 3.

Preparation of cured film samples
Preparation of substrate : An acrylic plate (Acrylite EX (registered trademark) manufactured by Mitsubishi Chemical Corporation) (size: 100 × 100 × 2 mm) mainly composed of polymethyl methacrylate (PMMA) was prepared as the substrate. The water contact angle of this substrate was approximately 70°. The method for measuring the water contact angle will be described later.

Application of Composition to Substrate Compositions 1 to 3 were applied to the substrate by spray coating.

The substrate on which the (wet) coating of the dry composition was formed was immediately placed in a hot air drying oven (YAMATO Scientific DKN402) and heated at a drying temperature of 70°C for 10 minutes to volatilize the solvent.

The substrate with the cured /uncured film formed thereon was removed from the hot air drying oven, and the uncured film was irradiated with ultraviolet light (ANUP4154, manufactured by Panasonic Electric Works) at an integrated exposure dose of 1000 mJ/ ^cm2 . In this way, cured film samples 1 to 7 and 9 to 15 with a thickness of approximately 10 μm were formed on the surface of the substrate.
Sample 8 is the same substrate as above.

Evaluation The prepared samples 1 to 15 were evaluated as follows.

Antiviral <Light source>
The following light sources were prepared. The spectra of each light source were evaluated using a fiber multichannel spectrometer, Flame (detection wavelength: 200-400 nm; manufactured by Ocean Photonics, Inc.), and it was confirmed that germicidal lamps, high-pressure mercury lamps, sunlight, and fluorescent lamps contained ultraviolet light with wavelengths of 350 nm or less.
Germicidal lamp (low-pressure mercury lamp): Toshiba germicidal lamp GL15, center wavelength 254 nm, received light intensity 0.15 mW/cm ² (measuring device: Hamamatsu Photonics H9535-254 was used to measure the received light intensity at a wavelength of 254 nm)
High-pressure mercury lamp: Panasonic, ANUP54, central wavelength 254 nm, 313 nm, 365 nm, 405 nm, etc. (average central wavelength: approximately 334 nm), received light amount 125 mW/cm ² (measuring device: Hamamatsu Photonics H9958, measured the received light amount at wavelength 365 nm)
Sunlight: central wavelength of over 200 nm, received light amount of 0.9 mW/cm ² (measuring device: Hamamatsu Photonics H9958, measured the received light amount at wavelength of 365 nm)
Fluorescent lamp: Toshiba Lightech, FHF32EX-N-H, central wavelengths 313 nm, 365 nm, and over 405 nm (average central wavelength 361 nm), received light amount 0.004 mW/cm ² (measuring instrument: Hamamatsu Photonics H9958, measured the received light amount at wavelength 365 nm)
LED-1: manufactured by Iwasaki Electric, LHPUV385, central wavelength 365 nm, received light amount 25.8 mW/cm ² (measuring device: Hamamatsu Photonics H9958 was used to measure the received light amount at a wavelength of 365 nm)
LED-2: Iwasaki Electric, LHPUV365, central wavelength 385 nm, received light amount 60.2 mW/cm ² (measuring device: Hamamatsu Photonics H9958 was used to measure the received light amount at a wavelength of 365 nm)
Black light: Spectronics Corporation, Mini MAX Series Model UV-5A, central wavelength 365 nm, received light intensity 0.45 mW/cm ² (measuring device: Hamamatsu Photonics H9958, measured the received light intensity at a wavelength of 365 nm)

<Light irradiation>
Each of Samples 1 to 15 was irradiated with light using a light source shown in Table 1 for a period of time shown in Table 1. Thereafter, each sample was allowed to stand for the period of time shown in Table 1.
In the "resting time after light irradiation" column in Table 1, a simple time such as "1 hour" means that the sample was rested in a dark place for that time at room temperature after light irradiation. Also, "hot water 50°C x 15 minutes" means that the sample was rested in a dark place for 15 minutes with the entire film immersed in hot water at 50°C.

<Method for evaluating antiviral activity>
Samples 1 to 15 were irradiated with light as described above and then allowed to stand for a predetermined period of time, and the antiviral activity was evaluated by the following method.
The antiviral activity was evaluated in accordance with JIS R1756 (2020) in a dark place. Specifically, an antiviral test was performed using bacteriophage Qβ, and the antiviral activity value (V) in a dark place was calculated using the following formula (1).
Antiviral activity value: V = Log ₁₀ (UV/TV) Formula (1)
TV: bacteriophage infectivity titer (pfu) 24 hours after instillation of bacteriophage solution
UV: Bacteriophage infectivity titer (pfu) immediately after dropping the bacteriophage liquid
In the present invention, when the antiviral activity value is V≧2, the sample is determined to exhibit good antiviral properties.
The reduction rate of infectious virus after 24 hours was calculated using the following formula (2).
Reduction rate (%) = (UV-TV)/UV x 100 Formula (2)
The antiviral activity values and infectious virus reduction rates of Samples 1 to 15 were as shown in Table 1.

When Samples 1 to 7, which are cured films of a composition containing a polyfunctional acrylic monomer having three or more functional groups, were irradiated with ultraviolet light having a wavelength of 350 nm or less at a light intensity of 0.15 mW/ ^cm2 , the antiviral activity value V was greater than 2 and the infectious virus reduction rate was greater than 99%, confirming that good antiviral properties were exhibited.
In contrast, even when Sample 8, which is a cured film of a composition containing an acrylic monomer having only one functional group, was irradiated with ultraviolet light having a wavelength of 350 nm or less at a light intensity of 0.15 mW/ ^cm2 , the antiviral activity value V was less than 2 and the reduction rate of infectious viruses was only about 84%, meaning that sufficient antiviral properties were not exhibited.
Furthermore, even in the case of Samples 9 to 13, which are cured films of a composition containing a polyfunctional acrylic monomer having three or more functional groups, when no light irradiation was performed, when irradiated with light having a wavelength of more than 350 nm, or when irradiated with light at an intensity of less than 0.15 mW/ ^cm2 , the antiviral activity value V was less than 2, and the reduction rate of infectious viruses was also smaller than that of Samples 1 to 7, and sufficient antiviral properties were not exhibited.

As already explained, the manifestation of antiviral activity according to the present invention is limited. Therefore, even when Samples 14 and 15, which are cured films of a composition containing a polyfunctional acrylic monomer having three or more functional groups, were irradiated with ultraviolet light having a wavelength of 350 nm or less at a light intensity of 0.15 mW/ ^cm2 , it was confirmed that the antiviral activity value V or the rate of reduction of infectious viruses was low when the sample was left to stand for a long period of time (two weeks) after light irradiation or when it was placed in a harsh environment (when it was immersed in 50°C warm water for one hour).
However, in the present invention, when or before it becomes difficult to maintain (sustain) the expression of the desired antiviral properties, it is possible to restore the antiviral properties by again irradiating the cured film of the present invention with ultraviolet light having a wavelength of 350 nm or less at an amount of received light of 0.15 mW/ ^cm2 or more. In other words, the antiviral film of the present invention can maintain the expression of good antiviral properties by appropriately irradiating it with ultraviolet light having a wavelength of 350 nm or less at an amount of received light of ^0.15 mW/cm2 or more, taking into account the conditions and environment of use, etc.

The static contact angle with water was measured for Samples 1 to 15. Specifically, a FACE contact angle meter CA-X150 (manufactured by Kyowa Interface Science) was used to drop a 2 μL water droplet onto the sample at room temperature, and the static contact angle after 20 seconds was measured by the θ/2 method. The sample was washed with distilled water, dried, and then measured at three points, and the average value was taken as the contact angle. The water contact angles of Samples 1 to 15 were as shown in Table 1.

Durability 1
Samples 1 to 15 were immersed in a 5 wt % aqueous solution of sodium hydroxide for 48 hours, then thoroughly rinsed with running water, dried, and visually evaluated for appearance. The evaluation criteria were as follows:
○: No change in appearance ×: Change in appearance

Durability 2
20 g of detergent containing an abrasive (Bathroom Look Polishing Wash, manufactured by Lion) was dropped onto Samples 1 to 15, and the samples were rubbed 100 times with a resin brush (EKL0034, manufactured by TOTO) while applying a load of 3 kg. Then, hydrophilicity evaluation (Evaluation 3) was performed. The obtained water contact angles were evaluated according to the following criteria.
◯: The water contact angle was 45° or less, and the difference in water contact angle before and after rubbing was less than 10°. △: The water contact angle was 45° or less, and the difference in water contact angle before and after rubbing was 10° or more. ×: The water contact angle was 45° or more. The results are shown in Table 1.

Claims (8)

A cured product of a composition comprising a polyfunctional (meth)acrylic monomer or oligomer having three or more (meth)acryloyl groups and a radical scavenger having a hydroxyphenyl group,
the cured product exhibits antiviral properties when irradiated with ultraviolet light having a wavelength of 350 nm or less at a light receiving amount of 0.15 mW/ ^cm2 or more, and the exhibited antiviral properties are maintained for a finite period of time in the absence of the irradiation ;
The composition contains 40% by weight or more and 99% by weight or less of the polyfunctional (meth)acrylic monomer or oligomer having three or more (meth)acryloyl groups . The cured product according to claim 1 , wherein the cumulative amount of ultraviolet light having a wavelength of 350 nm or less received is 40 mJ/cm ² or more. The cured product according to claim 1 or 2, wherein the composition contains 10 ppm or more and 10,000 ppm or less of the radical scavenger. The antiviral cured product according to any one of claims 1 to 3, wherein when it becomes difficult or there is a possibility that the expressed antiviral activity will not be maintained, or when the expressed antiviral activity has decreased, the antiviral cured product can be used by irradiating it again to restore the antiviral activity. The cured product according to any one of claims 1 to 4 , which contains sulfonic acid groups at least on the surface. The cured product according to any one of claims 1 to 5 , wherein the surface has a water contact angle of 40 degrees or less. An antiviral member comprising a substrate and the cured product according to any one of claims 1 to 6 formed on the surface of the substrate. An antiviral activity development or maintenance device comprising the antiviral member according to claim 7 and irradiation means capable of irradiating ultraviolet light having a wavelength of 350 nm or less,
an apparatus, characterized in that the antiviral member is able to exhibit or maintain antiviral properties by irradiating the antiviral member with ultraviolet light having a wavelength of 350 nm or less from the irradiation means.