JP2020081304A - Wiping sheet - Google Patents

Abstract

To provide a wiping sheet excellent in collectability of fine dirt such as dust and dust balls and collectability of fiber dirt such as hairs.SOLUTION: A wiping sheet is composed of a fiber sheet including pulp and a binder that is impregnated with aqueous medicine. The aqueous medicine includes carboxymethyl cellulose or salt thereof, and viscosity when the aqueous medicine is at 25°C is between 1000 mPa.s and 5000 mPa.s. The carboxymethyl cellulose or the salt thereof has the degree of etherification which is between 0.8 and 1.0. The aqueous medicine preferably contains 1 mass% to 20 mass% carboxymethyl cellulose or salt thereof. It is also preferable that the fiber roughness of the pulp is below 0.18 mg/m.SELECTED DRAWING: None

Description

The present invention relates to a wiping sheet.

Wet type cleaning sheets are commonly used for cleaning buildings such as floors, toilets and kitchens around water. The present applicant has previously proposed a cleaning sheet in which a nonwoven fabric having a basis weight of 40 to 200 g/m ² is impregnated with an aqueous detergent containing an amino-modified silicone and a thickener (see Patent Document 1). Further, the applicant used a substantially water-dispersible fiber sheet containing pulp and a binder impregnated with an aqueous agent, and the pulp having a fiber roughness of less than 0.18 mg/m 2 was used. A water-decomposable article has been proposed (see Patent Document 2).

JP, 2003-164407, A JP, 2008-291409, A

However, the sheets described in Patent Documents 1 and 2 have room for improvement in terms of enhancing both the ability to collect fine dirt such as dust and cotton dust and the ability to collect fiber dirt such as hair. It was

Therefore, an object of the present invention is to provide a wiping sheet that can solve the drawbacks of the prior art.

The present invention is a wiping sheet obtained by impregnating a fibrous sheet containing a pulp and a binder with an aqueous agent,
The aqueous drug contains carboxymethyl cellulose or a salt thereof, and the viscosity of the aqueous drug at 25° C. is 1000 mPa·s or more and 5000 mPa·s or less,
The carboxymethyl cellulose or a salt thereof provides a wiping sheet having an etherification degree of 0.8 or more and 1.0 or less.

According to the present invention, there is provided a wiping sheet which is excellent in collecting fine dirt such as dust and cotton dust and collecting fiber dirt such as hair.

Hereinafter, the wiping sheet of the present invention will be described based on its preferred embodiments. The wiping sheet of the present invention is obtained by impregnating a fibrous sheet containing pulp and a binder with an aqueous chemical. That is, the wiping sheet is a wet type sheet. Wiping in this specification includes both cleaning and wiping, and for example, cleaning of buildings such as floors, walls, ceilings and columns, cleaning of fittings and fixtures, wiping of articles, body and Includes cleaning of equipment related to the body.

The fiber sheet contains pulp and a binder. Examples of the pulp include bleached wood pulp such as softwood bleached kraft pulp (NBKP), softwood bleached sulfite pulp (NBSP), and hardwood bleached kraft pulp (LBKP); natural pulp such as cotton and hemp; rayon and lyocell. , Regenerated pulp such as cupra; mercerized pulp chemically swollen with alkali, chemically crosslinked pulp having a spiral structure, and microfibrous cellulose. These can be used alone or in combination. Of these, from the viewpoint of achieving both flexibility and strength of the sheet, it is preferable to use at least one of NBKP and NBSP, and it is more preferable to use both NBKP and NBSP.

The content of pulp contained in the fiber sheet is preferably 60% by mass or more, more preferably 70% by mass or more, and 100% by mass or less with respect to the total mass of the fiber sheet. The amount is preferably 97% by mass or less, and more preferably 97% by mass or less.

As long as the effects of the present invention are exhibited, the fiber sheet may contain fibers other than pulp as constituent fibers. Examples of other fibers include polyvinyl alcohol fibers, other polyolefin fibers, polyester fibers, and fibers using biodegradable polylactic acid. The content of these other fibers is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably substantially no content based on the total mass of the fiber sheet.

The fiber sheet constituting the wiping sheet of the present invention contains a binder. The binder is for exhibiting sufficient wet strength that can be withstood during use when the fiber sheet is impregnated with the below-mentioned aqueous agent. The content of the binder is preferably 1% by mass or more, more preferably 3% by mass or more, and further preferably 20% by mass or less, and 10% by mass based on the total mass of the fiber sheet. The following is more preferable.

As the binder, for example, an anionic binder such as a binder having a carboxyl group, polyvinyl alcohol, starch or a derivative thereof, sodium alginate, tranto gum, guar gum, xanthan gum, gum arabic, carrageenan, galactomannan, gelatin, casein, albumin, pullplan, Examples thereof include polyethylene oxide, viscose, polyvinyl ethyl ether, sodium polyacrylate, sodium polymethacrylate, polyacrylamide, hydroxylated derivatives of polyacrylic acid, polyvinylpyrrolidone/vinylpyrrolidone vinyl acetate copolymer and the like. When the wiping sheet of the present invention is water-dispersible as described below, it is preferable to use an anionic binder and polyvinyl alcohol among these binders. These binders can be used alone or in combination.

The anionic binder is an anionic binder that easily forms a carboxylate in water. Examples thereof include polysaccharide derivatives, synthetic polymers and natural products.

Examples of the polysaccharide derivative include carboxymethyl cellulose or a salt thereof, carboxyethyl cellulose or a salt thereof, carboxymethylated starch or a salt thereof, and the like.

Examples of the synthetic polymer include salts of polymers or copolymers of unsaturated carboxylic acids, salts of copolymers of unsaturated carboxylic acids and monomers copolymerizable with the unsaturated carboxylic acids, and the like. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic anhydride, maleic acid and fumaric acid. Examples of monomers copolymerizable with them include esters of these unsaturated carboxylic acids, vinyl acetate, ethylene, acrylamide, vinyl ether and the like. A particularly preferable synthetic polymer is one using acrylic acid or methacrylic acid as the unsaturated carboxylic acid, and specifically, polyacrylic acid, polymethacrylic acid, a salt of acrylic acid/methacrylic acid copolymer, acrylic acid or methacrylic acid. Examples thereof include salts of copolymers of an acid and an alkyl acrylate or an alkyl methacrylate.

Examples of natural products include sodium alginate, xanthan gum, gellan gum, taragant gum, pectin and the like.

From the viewpoint of increasing the wet strength of the fiber sheet, the binder is more preferably an alkali metal salt of carboxymethyl cellulose (CMC). From the same viewpoint, the CMC contained as a binder has an etherification degree of preferably 0.8 or more, more preferably 0.85 or more, and preferably 1.2 or less, more preferably 1.1 or less. is there.

The etherification degree can be measured, for example, by the following method. That is, 0.5 g to 0.7 g of CMC or CMC salt (anhydrous) is precisely weighed as a measurement sample, wrapped in filter paper, heated in a porcelain crucible to incinerate, and then cooled. .. The cooled sample after ashing is transferred to a 500 mL beaker, to which about 250 mL of water and 35 mL of 0.05 mol/L sulfuric acid are added to form a mixed solution, and the mixed solution is boiled for 30 minutes and then cooled. A phenolphthalein indicator was added to the mixed solution after cooling, and the excess acid remaining in the mixed solution was back-titrated with an aqueous 0.1 mol/L potassium hydroxide solution. The etherification degree is calculated from the equations (1) and (2).

A=[((axf)-(bxf'))/C]-P... Formula (1)
Degree of etherification (mol/C6)=G×A/(10000−(J×A)... Formula (2)
(A: amount of 0.05 mol/L sulfuric acid consumed [mL/g] per 1 g of measurement sample, a: amount of 0.05 mol/L sulfuric acid used [mL], f: titer of 0.05 mol/L sulfuric acid Coefficient, b: titration amount of 0.1 mol/L potassium hydroxide [mL], f′: titer coefficient of 0.1 mol/L potassium hydroxide, C: mass of measured sample [g], P: alkalinity [ mL/g], G: molecular weight of glucose (162), J: difference between molecular weight of CH ₂ COONa and hydrogen (80))

The above-mentioned alkalinity P can be measured by the following method, for example. About 1 g of CMC or CMC salt (anhydrous) is precisely weighed into a 300 mL beaker as a measurement sample, and about 200 mL of water is added and mixed to obtain a mixed solution. To this mixed solution, 5 mL of 0.05 mol/L sulfuric acid is added, boiled for 10 minutes, and then cooled. A phenolphthalein indicator is added to the cooled mixture and titrated with a 0.1 mol/L potassium hydroxide aqueous solution. In addition, a blank test is performed, and the alkalinity P is calculated from the following formula (3).
P=(bs)*f'/C... Formula (3)
(B: titration amount of 0.1 mol/L potassium hydroxide [mL], s: titration amount of 0.1 mol/L potassium hydroxide in blank test [mL], f′: 0.1 mol/L potassium hydroxide Titer coefficient, C: mass of measurement sample [g])

From the same viewpoint, the alkali metal salt of CMC contained as a binder has a viscosity of a 1% by mass aqueous solution at 25° C. of preferably 10 mPa·s or more, more preferably 15 mPa·s or more, and preferably 40 mPa·s. Hereafter, it is more preferably 35 mPa·s or less. Similarly, the CMC salt has a viscosity of a 5 mass% aqueous solution at 25° C. of preferably 2500 mPa·s or more, more preferably 2700 mPa·s or more, and preferably 4000 mPa·s or less, more preferably 3800 mPa·s. .. Similarly, CMC contained as a binder has a viscosity of a 5 mass% aqueous solution at 60° C. of preferably 1200 mPa·s or less. The viscosity of the CMC aqueous solution is measured, for example, by using a TVB-10 type viscometer (manufactured by Toki Sangyo Co., Ltd.), attaching an appropriate rotor, and rotating the rotor at 60 rpm to start the measurement. It can be a later value.

The wiping sheet of the present invention is obtained by impregnating the above-mentioned fiber sheet with a water-based chemical. The aqueous drug is an aqueous solution containing carboxymethyl cellulose (CMC) or a salt thereof, and the viscosity of the aqueous drug at 25° C. is preferably 1000 mPa·s or more, more preferably 1100 mPa·s or more, and preferably 5000 mPa·s or less, More preferably, it is 3000 mPa·s or less. The viscosity of the water-based drug is measured by the same method as the method for measuring the viscosity of CMC in a binder using an extract extracted from the wiping sheet by, for example, squeezing, pressing, or solid-liquid separating the wiping sheet. be able to. In order to adjust the viscosity of the aqueous drug to the above range, for example, the content of CMC or a salt thereof is adjusted, the content of water is adjusted, or CMC having an etherification degree described later is used. It can be adjusted appropriately.

As the salt of CMC contained in the aqueous drug, a metal salt of CMC is preferably used, and examples thereof include alkali metal salts such as sodium salt and potassium salt, and alkaline earth metal salts such as calcium salt and magnesium salt. Of these, the aqueous drug more preferably contains a salt of CMC, and further preferably contains a sodium salt of CMC, from the viewpoint of handleability during production and use.

The CMC or salt thereof contained in the aqueous drug has an etherification degree of CMC of preferably 0.8 or more, more preferably 0.85 or more, and 1.0 or less. It is preferably 0.95 or less. The etherification degree of CMC or its salt contained in the aqueous drug and the viscosity of the aqueous solution can be measured in the same manner as the method for measuring the viscosity of CMC in the binder.

According to the wiping sheet of the present invention having the above configuration, the pulp fibers can physically collect various stains by being entangled or caught in fine stains such as dust and cotton dust and fiber stains such as hair. .. In addition to this, the wiping sheet of the present invention, by containing CMC or a salt thereof in the water-based agent, highly develops the interaction between the pulp fiber and various stains, which is caused by increasing the viscosity of the water-based agent, and thus the various stains. Will be able to be successfully collected as if adsorbed to the sheet. As a result, the ability to collect fine dirt such as dust and cotton dust and the ability to collect fiber dirt such as hair become excellent.

In particular, according to a preferred embodiment of the present invention, by setting the viscosity of the water-based agent in the above-mentioned preferred range, the collecting property of fine dirt and fiber dirt is further enhanced, and the surface to be cleaned after cleaning is sticky, etc. Is also reduced and the usability after cleaning is enhanced. Further, by setting the degree of etherification of CMC used in the water-based medicine to the above-mentioned preferable range, in addition to the ability to collect fine dirt such as dust and cotton dust, the ability to collect fiber dirt such as hair is further improved. There is also an advantage that it can be increased.

The content of CMC or a salt thereof contained in the aqueous drug is preferably 1% by mass or more, more preferably 2% by mass or more, and 20% by mass or less based on the total mass of the aqueous drug. It is preferably 8% by mass or less. When the content of the CMC or the salt of CMC in the water-based agent is in such a range, the interaction between the constituent fibers of the sheet and the stain can be further enhanced, and as a result, the fine stain and the fiber stain can be collected. The sex can be further enhanced. When the aqueous drug contains a CMC salt, the content is based on the mass of the CMC salt, not the mass in terms of CMC.

Since the wiping sheet of the present invention contains CMC or a salt thereof in the water-based agent, the CMC on the surface of the wiping sheet to be used for cleaning (the surface facing the surface to be cleaned) or the CMC or the salt thereof is compared to the prior art. The abundance of salt is high. In particular, even when CMC is contained as a binder, CMC used as a binder is less likely to be eluted into an aqueous drug. Therefore, the content of CMC or a salt thereof contained in the aqueous drug can be measured by the following method. Can be determined. That is, the content of CMC or its salt contained in the aqueous drug can be calculated from the existing amount of Na element obtained using the energy dispersive X-ray spectrometer.

The content of water contained in the water-based agent is preferably 50% by mass or more based on the total weight of the water-based agent from the viewpoint of achieving both improved dirt trapping property and wet strength of the fiber sheet. , 60% by mass or more, more preferably 80% by mass or less, and further preferably 70% by mass.

From the same viewpoint, the viscosity of a 1% by mass aqueous solution of CMC or a salt thereof used for an aqueous drug at 25° C. is preferably 30 mPa·s or more, more preferably 1000 mPa·s or more, and 5000 mPa·s. It is preferably s or less, more preferably 4000 mPa·s or less. The viscosity of a 5% by mass aqueous solution of CMC or a salt thereof used for an aqueous drug is preferably 1000 mPa·s or more, more preferably 1100 mPa·s or more, and 5000 mPa·s or less. Is preferable and 3000 mPa·s or less is more preferable.

The pulp forming the fiber sheet in the wiping sheet preferably has a fiber roughness within a specific range. The fiber roughness is a scale representing the thickness of fibers such as pulp in which the thickness of the fibers is not constant in the length direction, and the smaller the value, the thinner the fibers. Specifically, the fiber roughness of the pulp is preferably less than 0.18 mg/m, and more preferably less than 0.17 mg/m. The lower limit of the fiber roughness is not particularly limited, and the smaller the value, the more preferable. However, if the fiber roughness is as low as about 0.1 mg/m, particularly about 0.15 mg/m, the effect of the present invention is sufficiently exhibited. It When the fiber roughness of the pulp is in such a range, the wiping sheet of the present invention has more excellent ability to collect fine dirt such as dust and cotton dust and fiber dirt such as hair. In addition to this, the wet strength of the wiping sheet is high, and there is an advantage that sufficient strength can be exhibited during use.

From the viewpoint that the wiping sheet after use can be easily discarded and the cleanliness of the surrounding environment is maintained, it is preferable that the fiber sheet constituting the wiping sheet is water dispersible. That is, the wiping sheet is preferably water dispersible. Water dispersible means that when the sheet is put into a large amount of water, the shape of the sheet collapses and the constituent fibers of the sheet disperse in water, but the shape of the sheet does not collapse due to the impregnation of an aqueous drug. .. In this way, since the sheet has a water dispersible property, the shape of the sheet collapses when the used wiping sheet is discarded in the presence of a large amount of water such as a flush toilet, It can be easily drained into sewage.

The degree of water dispersibility can be measured, for example, according to JIS P 4501 as the ease of loosening, and the lower this value, the better the water dispersibility of the sheet. The fibrous sheet means that it can be dispersed in water if the time for loosening (hydrolysis time) measured according to JIS P 4501 is less than 100 seconds, and preferably 80 seconds or less.

From the viewpoint of achieving both the wet strength of the fiber sheet and the dirt collecting performance, the impregnated amount of the aqueous agent is preferably 100 mass% or more, and 180 mass% or more, based on the dry mass of the fiber sheet. More preferably, it is 300% by mass or less, and further preferably 250% by mass or less.

The aqueous drug used in the present invention may contain other components generally used in a wiping sheet, in addition to the above components, as long as the effects of the present invention are exhibited. As other components, for example, a water-soluble organic solvent, a binder crosslinking agent, a surfactant, an antiseptic agent, a chelating agent, an electrolyte substance, a dye, a fragrance, an antioxidant, a pH adjusting agent and the like can be appropriately contained.

The aqueous agent used in the present invention preferably contains a water-soluble organic solvent from the viewpoint of improving the cleaning property and the dispersibility of the components in the aqueous agent. As the water-soluble organic solvent, for example, alcohols, polyols and glycol ethers can be contained. Examples of alcohols include monohydric alcohols such as methanol, ethanol and isopropyl alcohol. Examples of polyols include alkylene glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, and 1,3-butanediol, diethylene glycol, dipropylene glycol (DPG), polyethylene glycol, polypropylene glycol, sorbitol, and the like. Examples thereof include polyalkylene glycols, glycerins such as glycerin, diglycerin, and triglycerin.

Examples of the glycol ether include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol. Examples include monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monophenyl ether and the like. These polyols and glycol ethers can be used alone or in combination of two or more.

The content of the water-soluble organic solvent is preferably 5% by mass or more, and more preferably 10% by mass or more, based on the total mass of the aqueous agent, from the viewpoint of enhancing the dirt trapping property. It is preferably 30% by mass or less, and more preferably 25% by mass. When two or more water-soluble organic solvents are used in combination, the content is based on their mass. When the content of the water-soluble organic solvent is within such a range, the stickiness of the sheet is reduced and the feeling of use after cleaning is improved.

From the viewpoint of sufficiently exhibiting the wet strength of the fiber sheet at the time of cleaning, the water-based agent preferably contains the above-mentioned binder crosslinking agent. When an anionic binder such as CMC is used as the binder contained in the fiber sheet, a polyvalent metal salt is preferably used as the crosslinking agent, and a water-soluble salt of the polyvalent metal is more preferably used. As the polyvalent metal, one or more metals selected from the group consisting of alkaline earth metals such as calcium, strontium and barium, manganese, zinc, cobalt and nickel can be used. Examples of these metal salts include hydroxides, chlorides, sulfates, nitrates, carbonates, formates and acetates of the above-mentioned metals. More preferably, the metal ion is added in an amount of 0.25 mol or more, particularly 0.5 mol or more, relative to 1 mol of the carboxyl group in the binder. When the fiber sheet is made water-dispersible by containing the binder crosslinking agent, the wet strength and the water dispersibility can be well-balanced.

The content of the cross-linking agent contained in the aqueous drug is preferably 1% by mass or more and 2% by mass or more with respect to the total mass of the aqueous drug, from the viewpoint of successfully obtaining the balance between the wet strength and the water decomposability. Is more preferable, 5% by mass or less is preferable, and 4% by mass or less is further preferable.

From the viewpoint of enhancing the dirt collection performance, it is also preferable that the aqueous agent contains a surfactant. Examples of the surfactant used in the present invention include ionic surfactants, nonionic surfactants and amphoteric surfactants. Examples of the ionic surfactant include cationic surfactants such as benzalkonium cetyl phosphate, benzethonium chloride, benzalkonium chloride and cetylpyridinium chloride, and anionic surfactants such as alkylbenzene sulfonic acid. .. Examples of the nonionic surfactant include polyoxyethylene alkyl ether and the like. Examples of the amphoteric surfactant include alkyldimethylaminoacetic acid betaine, alkyldimethylamine oxide, alkylcarboxybetaine, alkylsulfobetaine and the like. These may be used alone or in combination as long as the effects of the present invention are exhibited.

When the aqueous agent contains a surfactant, the content of the surfactant is preferably 0.05 mass with respect to the total mass of the aqueous agent from the viewpoint of improving the dirt trapping performance and the feeling of use. % Or more, more preferably 0.1% by mass or more, preferably 3% by mass or less, more preferably 1% by mass. When two or more kinds of surfactants are contained, the content is the total amount of the surfactants.

From the viewpoint of enhancing the storage stability of the product, the aqueous drug preferably contains a preservative. Examples of the preservatives include benzoic acid and its salts, parabens such as alkyl paraoxybenzoate and benzyl paraoxybenzoate, phenoxyethanol, ethylhexanediol and the like. These may be used alone or in combination.
The content of the preservative is preferably 0.1% by mass or more and 0.8% by mass or less based on the total mass of the aqueous drug. When two or more preservatives are contained, the content is the total amount of preservatives.

The basis weight of the fiber sheet is preferably 20 g/m ² or more, more preferably 30 g/m ² or more, and preferably 100 g/m ² or less, from the viewpoint of achieving both the sheet strength and the impregnation property of the aqueous agent. Yes, and more preferably 80 g/m ² or less. From the same viewpoint, the wet thickness of the fiber sheet is preferably 0.1 mm or more, more preferably 0.2 mm or more, and preferably 1.0 mm or less, more preferably 0.8 mm or less. Here, as for the thickness of the wiping sheet, 1 part by weight of the dry fiber sheet is impregnated with 2 parts by weight of water to be in a wet state, and the thickness of the wet state fiber sheet under a pressure of 360 Pa is measured by a dial gauge type. Alternatively, it is measured by a laser displacement meter.

The wiping sheet of the present invention comprises, for example, wet-making a sheet-like pulp aggregate from a dispersion liquid containing pulp, press-dewatering or semi-drying the pulp aggregate, and then applying a binder for drying or coating. It can be manufactured by drying to a fibrous sheet containing pulp and binder, which is then impregnated with an aqueous agent. Examples of the wet paper machine used for wet papermaking include a short-net paper machine, a fourdrinier paper machine, a twin-wire paper machine, an on-top paper machine, a hybrid paper machine, and a round net paper machine. Examples of the drying device used for drying the sheet include a through air dryer and a Yankee dryer. Examples of the method of impregnating the fiber sheet with the aqueous agent include coating with a gravure coater, a die coater, or a spray.

The fiber sheet may be a single-layer structure sheet or a multi-layer structure sheet. Further, a large number of irregularities may be formed on one surface or both surfaces of the fiber sheet, and a large number of apertures penetrating in the thickness direction of the fiber sheet may be formed. The multi-layered sheet can be manufactured by, for example, stacking single-layered sheets and joining them with a binder, a water-soluble adhesive or the like, or by performing a joining process such as embossing.

The wiping sheet of the present invention having the above configuration is excellent in the ability to collect fine dirt such as dust and cotton dust, and the ability to collect fiber dirt such as hair while having sufficient sheet strength during use. It is a thing. The wiping sheet of the present invention is a sheet alone or is attached to a cleaning tool such as a wiper, and a building such as a floor surface, a wall surface, a cupboard, a window glass, a mirror, a door, a door knob, etc., a rug, a carpet, a desk. It is suitable for cleaning furniture such as dining tables, toilets, washrooms, kitchens, and other equipment and other equipment and items.

In addition to the above-mentioned applications, the wiping sheet of the present invention is used as a wet tissue, a makeup remover sheet, an insect repellent sheet, a sunscreen sheet, etc., for the human face, scalp, arms, legs, joints, armpits and other bodies. It is preferably used for cleaning the skin surface of. Further, when the wiping sheet of the present invention is configured to be water-dispersible, the used wiping sheet can be poured into water as it is and discarded, so that the wiping sheet can be easily discarded and the cleanliness of the surrounding environment is improved. There is also an advantage.

Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above-described embodiments.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the scope of the invention is not limited to such embodiments.

[Example 1]
As the pulp, a mixture of 90% by mass of NBKP was used. This pulp was dispersed in water to obtain a slurry having a fiber concentration of 2% by mass. CMC sodium salt (manufactured by Nippon Paper Industries Co., Ltd., Sunrose (registered trademark), model number: FT-3) as a binder was provided on one surface of a wet paper obtained by introducing this slurry into a short-net paper machine and performing wet paper making. 5 mass% aqueous solution of was applied by spraying. This wet paper was dried with a dryer to obtain a paper having a single layer structure in which a binder was applied on one surface. The basis weight of the obtained single-layer structure paper was 40 g/m ² . The obtained single-layer papers were superposed such that the coating surfaces of the binders face each other, and in that state, embossing was performed at room temperature to obtain a water-dispersible fiber sheet having a basis weight of 80 g/m ² . The resulting fibrous sheet had dimensions of length 250 mm x width 250 mm. The binder content was 5% by mass based on the total mass of the fiber sheet.

Then, the obtained fibrous sheet was impregnated with an aqueous chemical agent by spray coating, in which CMC sodium salt (manufactured by Nippon Paper Industries Co., Ltd., Sunrose (registered trademark), model number: FT-3) was mixed at a ratio shown in Table 1 below. Then, a wiping sheet was obtained. The aqueous agent was adjusted to have a viscosity at 25° C. of 1181 mPa·s and impregnated into a fiber sheet. The impregnated amount of the aqueous agent was 210% by mass based on the dry mass of the fiber sheet. The aqueous agent was an aqueous solution containing a surfactant, a water-soluble organic solvent, and a binder crosslinking agent in addition to CMC sodium salt.

[Example 2]
The same procedure as in Example 1 was repeated except that the CMC sodium salt used in Example 1 was mixed in the proportions shown in Table 1 below and the fiber sheet was impregnated with the aqueous chemical agent whose viscosity at 25° C. was adjusted to 4887 mPa·s. I got a wiping sheet.

[Examples 3 to 5]
A wiping sheet was obtained in the same manner as in Example 1 except that the CMC sodium salt shown below was used to impregnate the fiber sheet with the aqueous chemicals mixed in the proportions shown in Table 1 below. The etherification degree of the CMC sodium salt used in each example and the viscosity of the aqueous drug at 25° C. are as shown in Table 1 below.

Examples 3 to 5 used the following CMC sodium salt.
-Example 3: CMC sodium salt (manufactured by Nippon Paper Industries Co., Ltd., Sunrose (registered trademark), model number: F350HC)
-Example 4: CMC sodium salt (manufactured by Nippon Paper Industries Co., Ltd., Sunrose (registered trademark), model number: F60HC)
-Example 5: CMC sodium salt (manufactured by Nippon Paper Industries Co., Ltd., Sunrose (registered trademark), model number: F04LC)

[Comparative Example 1]
A wiping sheet was obtained in the same manner as in Example 1 except that the fibrous sheet was impregnated with an aqueous drug containing no CMC or its salt. The viscosity of the aqueous drug of this comparative example at 25° C. was as shown in Table 1 below.

[Comparative Examples 2 to 7]
A wiping sheet was obtained in the same manner as in Example 1 except that the fiber sheet was impregnated with the aqueous drug prepared by mixing the CMC sodium salt used in Example 1 in the ratio shown in Table 1 below. The viscosities at 25° C. of the aqueous medicines of the comparative examples were as shown in Table 1 below.

[Comparative Examples 8 to 10]
A wiping sheet was obtained in the same manner as in Example 1 except that the CMC sodium salt shown below was used to impregnate the fiber sheet with the aqueous chemicals mixed in the proportions shown in Table 1 below. The etherification degree of the CMC sodium salt used in each comparative example and the viscosity of the aqueous drug at 25° C. are as shown in Table 1 below.

The following CMC sodium salts were used in Comparative Examples 8 to 10.
Comparative Example 8: CMC sodium salt (manufactured by Nippon Paper Industries Co., Ltd., Sunrose (registered trademark), model number: F10LC)
Comparative Example 9: CMC sodium salt (manufactured by Nippon Paper Industries Co., Ltd., Sunrose (registered trademark), model number: F20LC)
Comparative Example 10: CMC sodium salt (manufactured by Nippon Paper Industries Co., Ltd., Sunrose (registered trademark), model number: F50LC)

[Evaluation of hair collecting properties]
In this evaluation, with a load of 500 g applied to the wiping sheets of the examples and comparative examples, 20 cm of 10 cm of hair as fiber stains were spread per 1 tatami (length 1820 mm x width 910 mm) vinyl chloride plate (Sangetsu stock). Made by the company, product name: Cushion floor Ishime Bianco (HM-2074)) surface was cleaned for 0.5 tatami. The wiping sheet was made to reciprocate 5 times in the sheet width direction with the longitudinal direction of the wiping sheet aligned with the length direction of the vinyl chloride plate. The number of hairs collected on the wiping sheet was measured after the completion of 5 reciprocating cleanings, and the collection ratio (%) was calculated from the following calculation formula to evaluate the hair collecting property. The higher the collection rate, the more excellent the hair collection property. The results are shown in Table 1. In Table 1, the comparative examples indicated by "-" were not evaluated.

<Calculation formula>
Hair collection rate (%)=100×(number of hairs collected on wiping sheet [end] after cleaning)/(number of scattered hairs [head])

[Evaluation of cotton dust collection properties]
In the present evaluation, the wiping sheets of Examples and Comparative Examples were loaded with 500 g of load, and 0.1 g of acrylic fiber having a fiber length of about 2 to 5 mm as model cotton dust was spread per 0.1 tatami mat on the vinyl chloride plate. The surface was cleaned by 0.5 tatami mat. The moving direction and the number of times of the wiping sheet were the same as in the evaluation of the hair collecting property. The state of the vinyl chloride plate before cleaning with the model cotton dust sprayed thereon and the state of the vinyl chloride plate after 5 reciprocating cleanings were visually observed, and the collectability of the cotton dust was evaluated based on the following criteria. .. In Table 1, the comparative examples indicated by "-" were not evaluated.

<Cotton dust collecting property>
◯: No model cotton dust remained on the plate surface after cleaning.
Δ: A part of the model cotton dust remains on the plate surface after the cleaning is completed, but it is smaller than that before the cleaning.
X: Model cotton dust remains on the plate surface even after the cleaning is completed, which is almost the same as the state before the cleaning.

[Evaluation of water dispersibility of wiping sheet]
The water dispersibility of the wiping sheets of Examples and Comparative Examples was evaluated according to JIS P4501. Place a 300 mL beaker containing 300 mL of water (water temperature 20 ± 5°C) on a magnetic stirrer, and adjust the rotation speed of the rotor (disk diameter 35 mm, thickness 12 mm) to 600 ± 10 rotations/minute. did. A fiber sheet having a size of 114 mm (×114 mm) was put thereinto, and a stopwatch was started. When the number of rotations of the rotor recovered to 540 rotations, the stopwatch was stopped, and the time was incremented by 1 second. This measurement was performed 3 times, and the arithmetic average value was taken as the water-disintegration time (seconds). .) and the water disintegration time was 100 seconds or more, the water dispersibility was determined to be poor (indicated by “x” in Table 1).The results are shown in Table 1 below. The comparative examples indicated by "-" were not evaluated.

[Evaluation of strength of wiping sheet]
The strength of the sheet is evaluated by visually observing the state of the sheet when the wiping sheet of the example or the comparative example is subjected to the above-mentioned [Evaluation of hair collecting property] and [Evaluation of cotton dust collecting property]. The sheet strength was observed and evaluated according to the following criteria.

<Sheet strength>
◯: No sheet breakage or collapse of shape was observed after completion of cleaning, and the sheet strength was high.
Δ: A part of the sheet was broken or collapsed during cleaning, but the sheet had a strength that can be used for cleaning.
X: Breakage and collapse of the shape of the sheet were observed during cleaning, and the sheet strength was so low that it could not be used for cleaning.

As shown in Table 1, the wiping sheet of each example containing a salt of CMC having a suitable range of etherification degree and impregnated with an aqueous agent having a viscosity of a suitable range contains CMC or a salt thereof. Comparative Example 1 impregnated with a non-aqueous agent, or the wiping sheet of Comparative Examples 2-10 impregnated with CMC having a degree of etherification not in the preferred range or impregnated with an aqueous agent having a viscosity not in the preferred range. Thus, both the collection properties of cotton dust and the collection properties of hair become excellent and excellent. Since the wiping sheet of Comparative Example 7 had a low sheet strength to the extent that the sheet was broken during cleaning, the evaluation of the collecting property was not performed.

Further, all of the wiping sheets of Examples and Comparative Examples except Comparative Example 7 had sufficient sheet strength at the time of use, but the shape of the sheet easily collapsed in a large amount of water, and the water dispersibility was poor. It was good. Since the sheet strength of the wiping sheet of Comparative Example 7 was so low that the sheet was broken during cleaning, the water dispersibility was not evaluated.

Therefore, the wiping sheet of the present invention is excellent in both the ability to collect fine dirt such as dust and cotton dust, and the ability to collect fiber dirt such as hair, by including CMC or a salt thereof in the aqueous agent. It becomes a thing. Further, the wiping sheet of the present invention has a sufficient sheet strength when used even when the fibrous sheet has a water-dispersible structure.

Claims (5)

A wiping sheet obtained by impregnating a fiber sheet containing pulp and a binder with an aqueous agent,
The aqueous drug contains carboxymethyl cellulose or a salt thereof, and the viscosity of the aqueous drug at 25° C. is 1000 mPa·s or more and 5000 mPa·s or less,
The said carboxymethyl cellulose or its salt is the wiping sheet whose etherification degree is 0.8 or more and 1.0 or less. The wiping sheet according to claim 1, wherein the aqueous drug contains 1% by mass or more and 20% by mass or less of carboxymethyl cellulose or a salt thereof. The wiping sheet according to claim 1 or 2, wherein the fiber roughness of the pulp is less than 0.18 mg/m. The wiping sheet according to claim 1, wherein the fiber sheet is water dispersible. The wiping sheet according to any one of claims 1 to 4, wherein the aqueous drug is impregnated in an amount of 100% by mass or more and 300% by mass or less with respect to a dry mass of the fiber sheet.