TWI892122B - Wiping sheet - Google Patents

Abstract

The wiping sheet of the present invention comprises a nonwoven fabric and an aqueous cleaning solution impregnated within the nonwoven fabric, wherein the aqueous cleaning solution contains an aromatic antimicrobial agent and a non-ionic surfactant. The non-ionic surfactant is preferably a polyoxyalkylene alkyl ether. The polyoxyethylene alkyl ether preferably has an ethylene oxide number of 20 or greater. The non-ionic surfactant preferably includes polyoxyethylene alkyl ethers having an ethylene oxide number of 20 or greater and polyoxyethylene alkyl ethers having an ethylene oxide number of less than 12.

Description

Wiping sheet

The present invention relates to a wet wipe sheet.

Wet sheets (cleaning sheets) are made by impregnating nonwoven fabric with an aqueous solution containing disinfectants. Because they are simple and easy to use, and disposable, they can be used continuously to maintain a clean surface. They are therefore used not only in homes but also in food factories, kitchens, and medical facilities for environmental remediation.

To ensure good hygiene of the objects being wiped, the aqueous cleaning solution contained in wet sheets often contains an antimicrobial or bactericidal agent. For example, Patent Document 1 describes a sterilization sheet in which a base sheet is impregnated with an aqueous sterilizing agent. The aqueous sterilizing agent contained in this sterilization sheet comprises a quaternary ammonium salt surfactant, an inorganic electrolyte and/or citrate, an alkaline agent, and water.

Patent Document 2 describes a solution containing a quaternary ammonium salt-type surfactant, potassium hydroxide, an aminocarboxylic acid-type chelating agent, and water in an aqueous disinfectant contained in a sterilization sheet.

Prior Art Literature Patent Literature

Patent Document 1: Japanese Patent Publication No. 2018-027916

Patent Document 2: Japanese Patent Publication No. 2019-112342

The present invention relates to a wiping sheet comprising a nonwoven fabric and an aqueous cleaning liquid impregnated in the nonwoven fabric.

In one embodiment, the aqueous cleaning solution preferably contains an aromatic antibacterial agent and a non-ionic surfactant.

When using a wet sheet to wipe a large surface, a sufficient amount of aqueous cleaning solution is supplied at the beginning of the wiping process, thereby providing sufficient hygiene to the surface. However, as the area to be wiped increases, the hygiene effect tends to gradually decrease. This tendency also applies to the technologies described in Patent Documents 1 and 2 above.

Therefore, the present invention relates to a wiping sheet that can maintain the hygienic performance of the wiped surface at the same level as at the beginning of wiping, even when the wiping area increases and the amount of cleaning liquid released decreases.

The following describes the present invention based on its preferred embodiments.

In the present invention, "wiping" includes both cleaning and wiping, including, for example, cleaning of floors, walls, ceilings, and columns, cleaning of furniture or supplies, wiping of objects, and wiping of the body and body-related equipment.

In the following, aqueous cleaning liquid may be referred to simply as "cleaning liquid."

This invention relates to a wiping sheet comprising a nonwoven fabric and an aqueous cleaning solution impregnated within the nonwoven fabric. The inventors conducted in-depth research on the composition of an aqueous cleaning solution that maintains its hygienic properties even after wiping large areas. The results surprisingly revealed that when the aqueous cleaning solution contains an aromatic antimicrobial agent and a nonionic surfactant, the virus removal performance of the wiping sheet can be significantly and effectively enhanced after wiping large areas.

Aromatic antimicrobial agents include alcohol-based antimicrobial agents with aromatic rings and antimicrobial agents with a structure in which one or more hydrogen atoms on an aromatic hydrocarbon nucleus are substituted with a hydroxyl group.

Representative examples of alcohol-based antimicrobial agents with aromatic rings include compounds in which a hydrogen atom in a benzene ring is replaced with a C1-3 alkyl group containing a hydroxyl group, or compounds in which a hydrogen atom in a phenolic hydroxyl group of a phenol is replaced with a C1-8 alkyl group containing a hydroxyl group. Among these compounds, particularly preferred examples include compounds in which the carbon atom furthest from the hydroxyl group in an alkyl group containing a hydroxyl group is bonded to a carbon atom constituting the benzene ring or an oxygen atom in a phenolic hydroxyl group of a phenol, thereby replacing the hydrogen atom on the benzene ring or the hydrogen atom of the phenolic hydroxyl group and the alkyl group. Examples of alcohol-based antimicrobial agents with aromatic rings include benzyl alcohol, phenoxyethanol, phenylethyl alcohol, and 3-phenylpropanol.

Also, known antimicrobial agents having a structure in which one or more hydrogen atoms of an aromatic hydrocarbon nucleus are substituted by a hydroxyl group include: p-hydroxybenzoic acid esters (also known as paraoxybenzoic acid esters), cypress alcohol, 5-chloro-2-(2,4-dichlorophenoxy)phenol (commonly known as triclosan), 4,4'-dichloro-2-hydroxydiphenyl ether (commonly known as diclosan), o-benzyl-p-chlorophenol (chlorophenol), isopropylmethylphenol (3-methyl-4-isopropylphenol, IPMP), p-chloro-m-xylenol (4-chloro-3,5-dimethylphenol, PCMX), rutinol, and cresol. Known para-hydroxybenzoic acid esters include methyl para-hydroxybenzoate, ethyl para-hydroxybenzoate, propyl para-hydroxybenzoate, isopropyl para-hydroxybenzoate, butyl para-hydroxybenzoate, isobutyl para-hydroxybenzoate, benzyl para-hydroxybenzoate, sodium para-hydroxybenzoate, and other para-hydroxybenzoic acid esters and their sodium salts.

In the present invention, in order to enhance the virus removal effect of the wiping sheet after wiping a large area, alcohol-based antibacterial agents having an aromatic ring or para-hydroxybenzoic acid esters are preferably used as aromatic antibacterial agents. Phenoxyethanol or para-hydroxybenzoic acid esters are more preferred, and phenoxyethanol or methyl para-hydroxybenzoate is particularly preferred.

To facilitate the reduction in hygienic performance when wiping large areas with aromatic antimicrobial agents, the amount of aromatic antimicrobial agents in the aqueous cleaning solution is preferably 0.01% by mass or greater, more preferably 0.05% by mass or greater, and particularly preferably 0.1% by mass or greater. Furthermore, to ensure safety and prevent damage to substrates, the amount of aromatic antimicrobial agents in the aqueous cleaning solution is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, and particularly preferably 0.3% by mass or less.

The amount of the aromatic antibacterial agent is preferably in the range of 0.01% by mass to 1.0% by mass, more preferably 0.05% by mass to 0.5% by mass, and particularly preferably 0.1% by mass to 0.3% by mass.

Because combined use with aromatic antimicrobial agents can effectively inhibit the degradation of hygiene performance after wiping large areas, the non-ionic surfactant contained in aqueous cleaning solutions is preferably an alkylene oxide-added non-ionic surfactant such as ethylene oxide, with polyoxyethylene alkyl ether being particularly preferred.

Polyoxyethylene alkyl ethers, also known as "alcohol ethoxylates," are non-ionic surfactants obtained by ethoxylating alcohol with ethylene oxide. The inventors have discovered that by incorporating both polyoxyethylene alkyl ethers and aromatic antimicrobial agents into the aqueous cleaning solution impregnated into nonwoven fabrics, a decrease in hygienic properties, such as virus removal, can be effectively prevented even after wiping a large area.

Polyoxyethylene alkyl ether is represented by the following general formula (1). In (1), it is a repeating part of ethylene oxide, wherein "H _2m+1 C _m " is a hydrophobic group and "O(CH ₂ -CH ₂ -O) _n " is a hydrophilic group.

H _2m+1 C _m O(CH ₂ CH ₂ O) _n H (1)

In the formula, m represents an integer greater than 1, and n represents an integer greater than 2.

From the perspectives of safety, processability, and usability, the cleaning solution impregnated into the wipe sheet is preferably aqueous. For this reason, the non-ionic surfactant is preferably highly water-soluble. For this reason, the ethylene oxide number of the polyoxyethylene alkyl ether in the non-ionic surfactant is preferably 4 or greater, more preferably 8 or greater, and even more preferably 20 or greater.

Furthermore, from the perspective of hygienic performance or cleaning properties, the ethylene oxide number of the polyoxyethylene alkyl ether is preferably 50 or less, particularly preferably 47 or less.

The ethylene oxide number of the polyoxyethylene alkyl ether is preferably 4 to 50, more preferably 8 to 47, and even more preferably 20 to 47.

Furthermore, the number of ethylene oxides is represented by "n" in the above formula (1).

Furthermore, the non-ionic surfactant preferably contains two or more polyoxyethylene alkyl ethers with different ethylene oxide numbers. More preferably, it contains a polyoxyethylene alkyl ether with an ethylene oxide number of 20 or greater and a polyoxyethylene alkyl ether with an ethylene oxide number of less than 12. It is particularly preferred that it contains a polyoxyethylene alkyl ether with an ethylene oxide number of 21 or greater and a polyoxyethylene alkyl ether with an ethylene oxide number of less than 12. This is because such a composition significantly suppresses the deterioration of hygienic performance after wiping a large area. Furthermore, it prevents the various components in the cleaning solution from adsorbing to the sheet fibers, allowing for efficient release of the cleaning solution onto the target surface.

In order to achieve the above-mentioned effects significantly, in polyoxyethylene alkyl ethers having an ethylene oxide number of less than 12, the ethylene oxide number is preferably 4 or more and less than 12, and particularly preferably 8 or more and 10 or less.

Regarding the length of the alkyl chain serving as the hydrophobic group in the polyoxyethylene alkyl ether, the carbon number m in formula (1) is preferably 6 or more and 24 or less, and more preferably 8 or more and 18 or less, in order to achieve an excellent balance with the number of ethylene oxides and thereby more easily exert an excellent hygienic performance degradation inhibitory effect. When the aqueous cleaning liquid contains two or more polyoxyethylene alkyl ethers having different ethylene oxide numbers, the carbon number m of the two may be different, but in order to more easily exert an excellent hygienic performance degradation inhibitory effect, it is more preferable that the carbon number m of the two be the same.

To easily suppress the degradation of wiping sheet hygiene after wiping a large area, the content of the non-ionic surfactant in the aqueous cleaning solution is preferably 0.01% by mass or greater, more preferably 0.02% by mass or greater, and particularly preferably 0.05% by mass or greater. Furthermore, to improve workability after wiping and prevent damage to the substrate, the content of the non-ionic surfactant in the aqueous cleaning solution is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, further preferably 3.0% by mass or less, and particularly preferably 2.0% by mass or less.

The content of the non-ionic surfactant in the aqueous cleaning solution is preferably in the range of 0.01 mass% to 5.0 mass%, more preferably 0.02 mass% to 4.0 mass%, further preferably 0.05 mass% to 3.0 mass%, and particularly preferably 0.05 mass% to 2.0 mass%.

To more easily suppress the degradation of the hygienic properties of the wiping sheet after wiping a large area, the content of the non-ionic surfactant in the aqueous cleaning solution is preferably 1 to 1000 parts by mass, and particularly preferably 50 to 800 parts by mass, per 100 parts by mass of the aromatic antibacterial agent.

Furthermore, to more easily suppress the degradation of the hygienic properties of the wiping sheet after wiping a large area, the amount of the non-ionic surfactant, particularly polyoxyethylene alkyl ether, is preferably 1 part by mass or more, and more preferably 10 parts by mass or more, per 100 parts by mass of the surfactant contained in the aqueous cleaning solution.

When the non-ionic surfactant contains a polyoxyethylene alkyl ether having an ethylene oxide number of 12 or greater and a polyoxyethylene alkyl ether having an ethylene oxide number of less than 12, the mass ratio C1:C2 of the polyoxyethylene alkyl ether having an ethylene oxide number of 12 or greater and the polyoxyethylene alkyl ether having an ethylene oxide number of less than 12 is preferably 100:0 to 10,000, particularly preferably 100:0 to 1,000, and most preferably 100:10 to 1,000, in order to more easily achieve the aforementioned significant effects brought about by containing the two or more polyoxyethylene alkyl ethers. Similarly, the mass ratio (C1'):C2 of the polyoxyethylene alkyl ether having a polyoxyethylene number of 20 or greater to the polyoxyethylene alkyl ether having a polyoxyethylene number of less than 12 is preferably 100:0 to 10,000, particularly preferably 100:0 to 1,000, and most preferably 100:10 to 1,000.

To further enhance the hygienic properties of the wipe sheet, the aqueous cleaning solution preferably contains a biocide. Preferred biocides include quaternary ammonium salts. Examples of quaternary ammonium salts include alkyltrimethylammonium salts, polyoxyethylenealkylmethylammonium salts, and alkylbenzyldimethylammonium salts such as benzylammonium chloride; quaternary ammonium salts containing an arylalkyl group cleaved by an ether group, a benzyl group, and two methyl groups; and alkylpyridinium salts such as alkylhexadecylpyridinium chloride. An example of a quaternary ammonium salt containing an arylalkyl group cleaved by an ether group, a benzyl group, and two methyl groups is benzethonium chloride. Examples of groups formed by cleaving an arylalkyl group with an ether group include groups formed by cleaving the alkyl chain of an arylalkyl group with an oxygen atom. For example, a general quaternary ammonium salt is represented by the following formula (2).

In the formula, ^R1 represents a straight or branched alkyl group having 6 to 28 carbon atoms, a straight or branched alkenyl group having 6 to 28 carbon atoms, an arylalkyl group having 7 to 28 carbon atoms, or a group formed by cleaving such an alkyl group, such an alkenyl group, or such an arylalkyl group with an amide, ester, or ether group. ^R2 represents a straight or branched alkyl group having 1 to 28 carbon atoms, a straight or branched alkenyl group having 1 to 28 carbon atoms, an arylalkyl group having 7 to 28 carbon atoms, a group formed by cleaving such an alkyl group, such an alkenyl group, or such an arylalkyl group with an amide, ester, or ether group, or an arylalkyl group with 7 to 28 carbon atoms. ^R3 and ^R4 represent the same or different straight or branched alkyl groups having 1 to 3 carbon atoms. ^R2 , ^R3 , and ^R4 may also form a pyridine ring. ^A- represents the anion that is the opposite ion of ammonium ion.

Examples of A ^- include carboxylate ions, sulfonate ions, and halogen ions. Among them, halogen ions are preferred, chloride ions and bromide ions are more preferred, and chloride ions are particularly preferred.

Based on its excellent hygienic properties, the quaternary ammonium salt is preferably an alkylbenzyldimethylammonium salt, and particularly preferably benzylammonium chloride.

To improve the hygienic properties of aqueous cleaning solutions, the content of quaternary ammonium salts in aqueous cleaning solutions is preferably 0.01% by mass or greater, more preferably 0.02% by mass or greater, and particularly preferably 0.03% by mass or greater. Furthermore, from a safety perspective, the content of quaternary ammonium salts in aqueous cleaning solutions is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and particularly preferably 1.0% by mass or less.

The content of quaternary ammonium salt in the aqueous cleaning solution is preferably in the range of 0.01 mass% to 5.0 mass%, more preferably in the range of 0.02 mass% to 3.0 mass%, and particularly preferably in the range of 0.03 mass% to 1.0 mass%.

In the present invention, in order to further improve the hygienic properties of the wiping sheet, it is also preferred that the aqueous cleaning solution contain an antibacterial agent other than the aromatic antibacterial agent.

Examples of antimicrobial agents other than aromatic antimicrobial agents include glycol compounds. These glycol compounds lack an aromatic ring and have two hydroxyl groups. Examples include propylene glycol, dipropylene glycol, isopentyl glycol, ethylene glycol, butanediol, pentanediol, 1,2-hexanediol, and 1,2-octanediol. Among these, dipropylene glycol is preferred due to its improved hygienic properties.

When a diol compound used as an antibacterial agent is included in an aqueous cleaning solution, the amount of the diol compound in the aqueous cleaning solution is preferably 0.01% by mass to 1.0% by mass, more preferably 0.02% by mass to 0.5% by mass, and particularly preferably 0.05% by mass to 0.3% by mass, in order to enhance antibacterial performance or ensure safety.

Aqueous cleaning solutions may contain, in addition to nonionic surfactants, cationic surfactants, anionic surfactants, and/or amphoteric surfactants, as long as the effects of the present invention are achieved. From the perspective of cleaning performance, it is preferred that the aqueous cleaning solution contain only nonionic surfactants as surfactants, or contain amphoteric surfactants in addition to nonionic surfactants. Examples of amphoteric surfactants useful in the present invention include at least one selected from lauryldimethylamine oxide, alkyl betaines, and 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaines. When an amphoteric surfactant is included, its amount in the aqueous cleaning solution can be suitably 0.01% by mass to 0.5% by mass.

Aqueous cleaning liquids may contain additives in addition to the aforementioned ingredients, within the scope of achieving the effects of the present invention. Examples of such additives include surfactants other than the aforementioned nonionic surfactants and amphoteric surfactants, biocides other than alcohols and quaternary ammonium salts, preservatives, fragrances, perfumes, deodorants, pH adjusters, metal chelating agents, viscosity adjusters, and solvents. These additives may be used individually or in combination. These additives may be used as needed based on the desired properties of the wipe sheet. When used, the amount of each additive in the aqueous cleaning liquid is preferably not less than 0.001% by mass and not more than 20% by mass.

For reasons of hygiene and safety, the pH of the aqueous cleaning solution used in the wipe sheet at 25°C is preferably 3.0 or higher, more preferably 4.0 or higher, and more preferably 11.0 or lower, more preferably 10.0 or lower. To achieve the pH of the cleaning solution within this range, the pH can be adjusted by adding a pH adjuster to a level sufficient to achieve the effects of the present invention.

The aqueous cleaning liquid constituting the wiping sheet of the present invention is preferably primarily composed of water. The water content of the aqueous cleaning liquid is preferably 80.0% by mass or greater, more preferably 90.0% by mass or greater, and more preferably 99.8% by mass or less, more preferably 99.0% by mass or less, relative to the total mass of the cleaning liquid.

Next, we will explain the nonwoven fabric that makes up the wiping sheet.

From the perspective of liquid transfer to the wiping surface, the ratio of the aqueous cleaning liquid impregnated into the nonwoven fabric relative to the mass of the nonwoven fabric is preferably 100% by mass or greater, more preferably 200% by mass or greater. From the perspective of liquid transfer to the wiping surface, it is preferably 600% by mass or less, more preferably 500% by mass or less.

Examples of fibers that make up nonwoven fabrics include regenerated fibers, natural fibers, and synthetic fibers. From the perspectives of safety, ease of impregnation with aqueous detergents, and retention, regenerated fibers are preferably included. Examples of regenerated fibers include rayon fibers and cellulose acetate fibers. From the perspectives of safety and versatility, rayon fibers are preferred. Examples of natural fibers include cotton, linen, and collagen fibers. From the perspective of manufacturing efficiency, synthetic fibers are preferably made from fiber-forming resins. Examples of such resins include various thermoplastic resins. Examples of thermoplastic resins include polyolefin resins such as polyethylene (PE) and polypropylene (PP), polyester resins such as polyethylene terephthalate (PET), polyamide resins, vinyl resins such as polyvinyl chloride and polystyrene, acrylic resins such as polyacrylic acid and polymethyl methacrylate, and fluororesins such as polyperfluoroethylene. These resins may be used alone or in combination of two or more.

From the perspective of ease of impregnation and retention of aqueous cleaning liquids, the proportion of regenerated fibers in the nonwoven fabric is preferably 1% by mass or greater. From this perspective, the proportion of regenerated fibers in the nonwoven fabric is particularly preferably 5% by mass or greater, and even more preferably 10% by mass or greater. On the other hand, from the perspective of ease of wiping, the proportion of regenerated fibers in the nonwoven fabric is preferably 99% by mass or less, and even more preferably 90% by mass or less.

From the perspective of impregnation with aqueous detergent, the mass (g/m ² ) of regenerated fiber per 1 m ² of the nonwoven fabric in its dry state is preferably 5 g/m ² or greater, more preferably 10 g/m ² or greater. From the perspective of continuously releasing an appropriate amount of aqueous detergent during wiping, the mass (g/m ² ) of regenerated fiber per 1 m ² of the nonwoven fabric is preferably 60 g/m ² or less, more preferably 50 g/m ² or less, and even more preferably 40 g/m ² or less.

From the perspective of hygiene, the ratio of the mass of aqueous cleaning liquid per 1g of nonwoven fabric to the mass of regenerated fiber per ^1m2 of nonwoven fabric (g/ ^m2 ) is preferably 0.05 or greater, more preferably 0.075 or greater, and even more preferably 0.01 or greater. From the perspective of liquid transfer to the wiping surface and hygiene, the ratio of the mass of aqueous cleaning liquid per 1g of nonwoven fabric to the mass of regenerated fiber per ^1m2 of nonwoven fabric (g/ ^m2 ) is preferably 1.0 or less, more preferably 0.6 or less, and even more preferably 0.4 or less.

From the perspective of hygienic performance, the ratio of the mass of the aromatic antimicrobial agent per 1g of aqueous detergent solution for nonwoven fabric to the mass of the regenerated fiber per ^1m2 of nonwoven fabric (g/ ^m2 ) is preferably 0.0002 or greater, more preferably 0.0003 or greater, and even more preferably 0.0005 or greater. From the perspective of hygienic performance, the ratio of the mass of the aromatic antimicrobial agent per 1g of aqueous detergent solution for nonwoven fabric to the mass of the regenerated fiber per ^1m2 of nonwoven fabric (g/ ^m2 ) is preferably 0.005 or less, more preferably 0.003 or less, and even more preferably 0.001 or less.

From the perspective of hygienic performance, the ratio of the mass of the non-ionic surfactant per 1g of aqueous detergent solution for the nonwoven fabric to the mass of the regenerated fiber per ^1m2 of the nonwoven fabric (g/ ^m2 ) is preferably 0.0001 or greater, more preferably 0.0005 or greater, and even more preferably 0.0008 or greater. From the perspective of hygienic performance, the ratio of the mass of the non-ionic surfactant per 1g of aqueous detergent solution for the nonwoven fabric to the mass of the regenerated fiber per ^1m2 of the nonwoven fabric (g/ ^m2 ) is preferably 0.02 or less, more preferably 0.01 or less, and even more preferably 0.007 or less.

From the perspective of workability during wiping, the fiber density of the regenerated fiber is preferably 0.5 dtex or greater, more preferably 0.75 dtex or greater, and even more preferably 1.0 dtex or greater. Furthermore, the upper limit is preferably 3.0 dtex or less, more preferably 2.5 dtex or less, and even more preferably 2.0 dtex or less.

When a nonwoven fabric contains synthetic fibers, the proportion of synthetic fibers in the nonwoven fabric is preferably 99% by mass or less, particularly preferably 90% by mass or less, and even more preferably 80% by mass or less, in order to facilitate impregnation and retention of aqueous cleaning solutions. On the other hand, in order to improve wiping efficiency and stain removal, the proportion of synthetic fibers in the nonwoven fabric is preferably 5% by mass or more, and even more preferably 10% by mass or more.

From the perspective of wiping workability and stain removal efficiency, the fiber density of synthetic fibers is preferably 0.5 dtex or greater, more preferably 1 dtex or greater, and even more preferably 1.2 dtex or greater. Furthermore, the upper limit is preferably 4 dtex or less, more preferably 3.5 dtex or less, and even more preferably 3 dtex or less.

In nonwoven fabrics, fibers such as regenerated fibers, synthetic fibers, and natural fibers are stacked, intertwined, or bonded together to form a fiber aggregate. The fibers that make up a nonwoven fabric may or may not be fused. Wiping sheets may consist solely of nonwoven fabric or may include other sheet materials or other components in addition to nonwoven fabric.

The nonwoven fabric comprising the wiping sheet preferably has a dry basis weight of 30 g/ ^m² or greater, more preferably 35 g/ ^m² or greater, and even more preferably 40 g/ ^m² or greater. The upper limit is preferably 100 g/m² or ^less , more preferably 90 g/ ^m² or less, and even more preferably 80 g/ ^m² or less. "Dry" means the nonwoven contains 3% by mass or less of water. This dry basis weight allows the wiping sheet to be fully impregnated with aqueous detergent, thereby exhibiting excellent hygienic properties and absorbing a greater amount of removed stains, resulting in superior wiping strength.

Nonwoven fabrics that can be used include spunlace nonwovens, meltblown nonwovens, spunbond nonwovens, air-through nonwovens, resin-bonded nonwovens, and needle-punched nonwovens. Composites of these nonwovens can also be used. Of these, spunlace nonwovens are preferred because they tend to entangle with fibrous dirt such as hair and lint.

The nonwoven fabric and the wiping sheet of the present invention comprising the nonwoven fabric can be formed into a generally rectangular sheet having a longitudinal direction and a width direction perpendicular to the longitudinal direction. Furthermore, the wiping sheet may or may not have a concave-convex portion with a macroscopic pattern of curved portions on at least one side.

To provide sufficient strength during use, the wiping sheet of the present invention may further include a scrim to support the nonwoven fabric. The scrim is preferably positioned in the center of the nonwoven fabric in the thickness direction. The scrim is capable of being intertwined with the synthetic fibers that comprise the nonwoven fabric, and may take the form of a mesh, lattice, or thread.

As a raw material for the scrim, resins can be used. Examples of the resin include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyamide resins such as nylon 6 and nylon 66, acrylonitrile-based resins such as polyacrylonitrile, vinyl-based resins such as polyvinyl chloride and polystyrene, and vinylidene-based resins such as polyvinylidene chloride.

From the perspective of achieving both intertwining properties between the constituent fibers and the scrim, and the strength of the wiping sheet, the thread diameter (cross-sectional diameter) of the scrim can be appropriately adjusted based on the degree of intertwining of the fibers, preferably being 10 μm or greater, more preferably 100 μm or greater, and preferably 2000 μm or less, more preferably 1000 μm or less. The thread diameters of the scrim may vary in some areas or may be the same. In the case of partially varying thread diameters, the thread diameter of the scrim is set to the average value. The basis weight of the scrim is preferably 1 g/m ² or more, more preferably 3 g/m ² or more, and preferably 20 g/m ² or less, more preferably 10 g/m ² or less.

The aforementioned wiping sheet can be used alone or attached to a cleaning tool such as a scraper to clean floors, walls, and other structures; furniture such as cabinets, window panes, mirrors, doors, and doorknobs; furniture such as mats, carpets, and tables; and for wiping kitchens, toilets, and the body, as well as sanitary products and packaging.

In particular, because the nonwoven fabric of the present invention is impregnated with a cleaning solution containing an aromatic antimicrobial agent and a non-ionic surfactant, the wiping sheet effectively suppresses the degradation of hygienic properties, such as virus removal, even after wiping a large area. This ensures excellent hygienic performance and reduces the number of sheets used, thereby reducing cleaning costs and improving cleaning efficiency.

The present invention has been described above based on the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments.

Regarding the above-mentioned embodiments, the present invention further discloses the following wiping sheet.

<1>

A wiping sheet comprises a nonwoven fabric and an aqueous cleaning liquid impregnated in the nonwoven fabric, wherein the aqueous cleaning liquid contains an aromatic antibacterial agent and a non-ionic surfactant.

<2>

In the wiping sheet described in <1> above, the content of the non-ionic surfactant in the aqueous cleaning solution is preferably 0.01 mass% or more, more preferably 0.02 mass% or more, particularly preferably 0.05 mass% or more, further preferably 5.0 mass% or less, more preferably 4.0 mass% or less, further preferably 3.0 mass% or less, and particularly preferably 2.0 mass% or less.

<3>

The wiping sheet described in <1> or <2> above, wherein the non-ionic surfactant is a polyoxyethylene alkyl ether.

<4>

The wiping sheet described in <3> above, wherein the number of ethylene oxides in the polyoxyethylene alkyl ether is 20 or greater.

<5>

The wiping sheet described in <3> or <4> above contains the polyoxyethylene alkyl ether having an ethylene oxide number of 20 or more and the polyoxyethylene alkyl ether having an ethylene oxide number of less than 12.

<6>

In the wiping sheet described in any one of <1> to <3> above, the amount of the aromatic antibacterial agent in the aqueous cleaning solution is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more, and is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, and particularly preferably 0.3% by mass or less.

<7>

The wipe sheet described in any one of <1> to <6> above, wherein the aromatic antibacterial agent is phenoxyethanol or methyl parahydroxybenzoate.

<8>

The wiping sheet described in any one of <1> to <7> above, further comprising a quaternary ammonium salt.

<9>

The wiping sheet described in <8> above, wherein the quaternary ammonium salt is benzyl ammonium chloride.

<10>

The wiping sheet as described in any one of <1> to <9> above, further comprising a diol compound.

<11>

In the wiping sheet described in <10> above, the amount of the diol compound in the aqueous cleaning solution is preferably from 0.01% by mass to 1.0% by mass, more preferably from 0.02% by mass to 0.5% by mass, and particularly preferably from 0.05% by mass to 0.3% by mass.

<12>

The wiping sheet described in <10> or <11> above, wherein the diol compound is dipropylene glycol.

<13>

A wiping sheet as described in any one of <1> to <12> above, wherein the non-woven fabric contains regenerated fiber.

<14>

The wiping sheet described in <13> above, wherein the regenerated fiber is rayon.

<15>

In the wiping sheet described in any one of <1> to <14> above, the ratio of the regenerated fiber in the nonwoven fabric is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. Furthermore, the ratio of the regenerated fiber in the nonwoven fabric is preferably 99% by mass or less, and even more preferably 90% by mass or less.

<16>

The wiping sheet according to any one of items <1> to <15> above, wherein the basis weight of the nonwoven fabric is preferably 30 g/m ² or more, more preferably 35 g/m ² or more, and further preferably 40 g/m ² or more; further, the basis weight of the nonwoven fabric is preferably 100 g/m ² or less, more preferably 90 g/m ² or less, and further preferably 80 g/m ² or less.

<17>

The wiping sheet as described in any one of <1> to <16> above, wherein the mass of the regenerated fiber per 1m ² of the non-woven fabric is preferably 5 g/m ² or more, more preferably 10 g/m ² or more, and the mass of the regenerated fiber per 1m ² of the non-woven fabric is preferably 60 g/m ² or less, more preferably 50 g/m ² or less, and further preferably 40 g/m ² or less.

<18>

In the wiping sheet described in any one of <1> to <17> above, the ratio of the aqueous cleaning liquid impregnated in the nonwoven fabric to the mass of the nonwoven fabric is preferably 100% by mass or more, more preferably 200% by mass or more, and the ratio of the aqueous cleaning liquid impregnated in the nonwoven fabric is preferably 600% by mass or less, more preferably 500% by mass or less.

<19>

The wiping sheet as described in any one of <1> to <18> above, wherein the ratio of the mass of the aqueous cleaning solution per 1g of the nonwoven fabric to the mass of the regenerated fiber per ^1m2 of the nonwoven fabric (g/ ^m2 ) is preferably 0.05 or more, more preferably 0.075 or more, and even more preferably 0.01 or more; and the ratio of the mass of the aqueous cleaning solution per 1g of the nonwoven fabric to the mass of the regenerated fiber per ^1m2 of the nonwoven fabric (g/ ^m2 ) is preferably 1.0 or less, more preferably 0.6 or less, and even more preferably 0.4 or less.

<20>

The wiping sheet as described in any one of <1> to <19> above, wherein the ratio of the mass of the aromatic antimicrobial agent per 1g of the aqueous cleaning solution of the nonwoven fabric to the mass of the regenerated fiber per ^1m2 of the nonwoven fabric (g/ ^m2 ) is preferably 0.0002 or more, more preferably 0.0003 or more, and even more preferably 0.0005 or more; and the ratio of the mass of the aromatic antimicrobial agent per 1g of the aqueous cleaning solution of the nonwoven fabric to the mass of the regenerated fiber per ^1m2 of the nonwoven fabric (g/ ^m2 ) is preferably 0.005 or less, more preferably 0.003 or less, and even more preferably 0.001 or less.

<21>

The wiping sheet according to any one of items <1> to <20>, wherein the ratio of the mass of the non-ionic surfactant per 1g of the aqueous cleaning solution of the non-woven fabric to the mass of the regenerated fiber per ^1m2 of the non-woven fabric (g/ ^m2 ) is preferably 0.0001 or more, more preferably 0.0005 or more, and further preferably 0.0008 or more; and the ratio of the mass of the non-ionic surfactant per 1g of the aqueous cleaning solution of the non-woven fabric to the mass of the regenerated fiber per ^1m2 of the non-woven fabric (g/ ^m2 ) is preferably 0.02 or less, more preferably 0.01 or less, and further preferably 0.007 or less.

[Example]

The present invention is described in more detail below using examples. However, the scope of the present invention is not limited to these examples. Unless otherwise specified, "%" means "mass %."

[Examples 1 to 10 and Comparative Examples 1 to 5]

The cellulose-containing nonwoven fabric used was a hydroentangled spunlace of synthetic and cellulose-containing fibers, with a scrim (polypropylene, approximately 100 μm diameter, 5 g/ ^m² basis weight) in the center of the thickness. The nonwoven fabric had a fiber composition of PET (1.7 dtex): acrylic (1.0 dtex): rayon (1.7 dtex) in a mass ratio of 70:15:15. Its dry basis weight was 70 g/ ^m² , and its dimensions were 285 mm x 205 mm.

The nonwoven fabric is impregnated with an aqueous cleaning solution at 350% by mass relative to the mass of the nonwoven fabric to produce the target wet wiping sheet.

The aqueous cleaning solution was prepared as follows: in addition to 0.05% amphoteric surfactant (lauryldimethylamine oxide), 2% alcohol, 1% solvent (methylpropylene glycol), 0.01% preservative (1,2-benzoisothiazolin-3-one), and 0.01% metal chelating agent, the components listed in Table 1 were also present in the amounts listed therein. A pH adjuster was also included to maintain a pH of 9.0. The pH of the cleaning solution at 25°C before immersion was adjusted using a pH meter (HORIBA, pH meter F22). The water content in the cleaning solution was at least 90.0% by mass. The amounts of each component in Table 1 refer to the active ingredient content of the preparation, not the total amount of the preparation.

[Virus Removal Activity Value]

A load of 0.64 kN/ ^m² was applied to the wet wiping sheets of the Examples and Comparative Examples. Twenty floors (equivalent to 32.4 ^m² ) were wiped continuously at a wiping speed of 1 m/s using a floor covering (Combit New Advance 101, manufactured by WOOD ONE). The cleanability of the floor covering before wiping was determined by washing it with a 70% ethanol solution and drying it with Kimtowel (registered trademark). The wipe sheets of the Examples and Comparative Examples were evaluated after wiping according to the "Bacteria Removal Performance Test for Wet Wipes" established by the Japan Cleaning Paper and Cotton Industries Association.

Influenza A virus was selected as the virus type. The number of viruses was prepared to be 1.1×10 ⁹ /mL. 0.01mL of the virus preparation solution was inoculated on a stainless steel plate and spread to an area of 15mm×90mm using a cell spreader. The plate was wiped using the wiping sheet of the embodiment and the comparative example after the above wiping. The wiping operation was performed 5 times back and forth on the plate at intervals of about 2 seconds while applying a load of 0.78kN/m ² to the wiping sheet. After the wiping operation was completed, the stainless steel plate was placed in an environment of 25°C for 5 minutes, and then the wiping part was wiped back and forth 10 times using a rag (made). The wipe was pre-soaked with 1.5 mL of SCDLP (Soybean Casein Digest Lecithin Polysorbate) medium. The medium was then stirred with a vortex mixer to obtain a virus suspension. A blank sample was prepared by performing the above procedure without wiping with the wipe.

A 10-fold dilution series of virus suspension was prepared using Eagle's Minimum Essential Medium (EMEM). The viral infectivity titer per 0.1 mL of the virus suspension was determined using a plaque assay, and the viral infectivity titer (PFU/stainless steel plate) was calculated.

Using control materials, the same procedure was performed to calculate the common logarithm mean of the measured viral infection titers (PFU/stainless steel plate). Furthermore, a 150% solution of 0.05% polysorbate 80 in physiological saline was used instead of the detergent to impregnate fine white cloth No. 3 (285 mm x 205 mm), as specified in JIS L0803 for color fastness tests. Fine white cloth No. 3 had been previously cleaned and sterilized according to the test method.

The virus removal activity values were quantified using the following formula. The results are shown in Table 1.

Virus removal activity value = X'-Y'

X': The average common logarithm of the viral infection titer (PFU/stainless steel plate) obtained by repeated testing three times on the photomicrograph.

Y': The average common logarithm of the viral infection titer (PFU/stainless steel plate) obtained by repeated testing three times on the wipe sheet used as the test object.

Based on the virus removal activity values calculated using the above formula, virus removal performance is scored according to the following criteria.

S: >4.0

A: 3.5~4.0

B: 2.5~3.4

C: 2.0~2.4

D: 0~1.9

The results shown in Table 1 demonstrate that the addition of a non-ionic surfactant and an aromatic antimicrobial agent to the aqueous cleaning solution significantly improved the wiping sheet's virus removal activity after wiping 20 floors. This demonstrates that the wiping sheet of the present invention effectively suppresses the degradation of the hygienic properties of the surface being wiped from the initial stage of wiping, even when the amount of cleaning solution released decreases as the wiping area increases.

[Industrial Availability]

According to the present invention, even when the amount of cleaning liquid released decreases as the wiping area increases, the sanitary performance of the wiped surface can be effectively suppressed from the initial wiping stage.

Claims (15)

A wiping sheet comprises a nonwoven fabric and an aqueous cleaning solution impregnated in the nonwoven fabric. The aqueous cleaning solution contains an aromatic antimicrobial agent, a nonionic surfactant, and a quaternary ammonium salt. The nonionic surfactant contains a polyoxyethylene alkyl ether, wherein the polyoxyethylene alkyl ether includes polyoxyethylene alkyl ethers having an ethylene oxide number of 20 or greater and polyoxyethylene alkyl ethers having an ethylene oxide number of 8 or greater and less than 12. The aromatic antimicrobial agent contains phenoxyethanol and/or methyl parahydroxybenzoate. The wiping sheet as claimed in claim 1, wherein the wiping sheet is used for wiping floors. The wiping sheet of claim 1 or 2, wherein the content of the non-ionic surfactant in the aqueous cleaning solution is not less than 0.01 mass % and not more than 5.0 mass %. The wiping sheet of claim 1 or 2, wherein the amount of the aromatic antimicrobial agent in the aqueous cleaning solution is not less than 0.01 mass % and not more than 0.3 mass %. The wiping sheet of claim 1 or 2, wherein the quaternary ammonium salt contains benzyl ammonium chloride. The wiping sheet of claim 1 or 2, further comprising a diol compound. The wiping sheet as claimed in claim 6, wherein the above-mentioned diol compound contains dipropylene glycol. For the wiping sheet of claim 1 or 2, the mass of the regenerated fiber per 1 ^m2 of the nonwoven fabric is not less than 5 g/ ^m2 and not more than 60 g/ ^m2 . The wiping sheet of claim 1 or 2, wherein the ratio of the aqueous cleaning liquid impregnated in the nonwoven fabric relative to the mass of the nonwoven fabric is not less than 100 mass % and not more than 600 mass %. The wiping sheet of claim 1 or 2, wherein the ratio of the mass of the aqueous cleaning solution per 1 g of the nonwoven fabric to the mass of the regenerated fiber per 1 m ² of the nonwoven fabric (g/m ² ) is not less than 0.05 and not more than 1.0. The wiping sheet of claim 1 or 2, wherein the ratio of the mass of the aromatic antimicrobial agent per 1 g of the aqueous cleaning solution of the nonwoven fabric to the mass of the regenerated fiber per 1 m ² of the nonwoven fabric (g/m ² ) is not less than 0.0002 and not more than 0.005. The wiping sheet of claim 1 or 2, wherein the ratio of the mass of the non-ionic surfactant per 1 g of the aqueous cleaning solution of the non-woven fabric to the mass of the regenerated fiber per 1 m ² of the non-woven fabric (g/m ² ) is not less than 0.0001 and not more than 0.02. The wiping sheet of claim 1 or 2, wherein the ratio of recycled fiber in the nonwoven fabric is not less than 10% by mass and not more than 90% by mass. The wiping sheet of claim 1 or 2, wherein the amount of synthetic fiber in the nonwoven fabric is not less than 10% by mass and not more than 90% by mass. The wiping sheet of claim 1 or 2, wherein the basis weight of the nonwoven fabric in a dry state is not less than 30 g/ ^m2 and not more than 100 g/ ^m2 .