Wet wipe for cleaning

Abstract

To provide a cleaning wet sheet that exhibits improved performance of wiping off oil stain and liquid stain.SOLUTION: A cleaning wet sheet 100 has a base paper sheet impregnated with a chemical agent, where the chemical agent has a hydrogen ion exponent of 8.0 to 9.0, while containing 0.05 mass% to 0.15 mass% of a polyoxyethylene alkyl ether and 5.00 mass% to 15.00 mass% of ethanol.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a wet sheet for cleaning.

Background Art

[0002] When cleaning floors, around the kitchen, etc., it is convenient to use a dedicated disposable sheet. Therefore, inventions of cleaning sheets used for cleaning various surfaces to be cleaned are known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a cleaning sheet, it is important to improve the wiping performance against dirt on the surface to be cleaned. Conventionally, for example, the wiping performance against dirt has been improved by impregnating the sheet with a dedicated chemical solution. However, oil stains (stains where oil adheres and dries and adheres firmly), such as those seen around the kitchen, and liquid stains (stains where liquid adheres and dries and adheres firmly) are often difficult to remove. Therefore, further improvement in the wiping performance against these stains has been demanded.

[0005] An object of the present invention is to improve the wiping performance of a wet sheet for cleaning against oil stains and liquid stains.

Means for Solving the Problems

[0006] To solve the above problems, the invention according to claim 1 is a wet sheet for cleaning in which a base paper sheet is impregnated with a chemical solution, The chemical solution has a hydrogen ion exponent of 8.0 to 9.0 and contains 0.05% to 0.15% by mass of polyoxyethylene alkyl ether and 5.00% to 15.00% by mass of ethanol. and comprising a diamond-shaped embossed block formed by a plurality of convex embosses that are convex on the first surface of the wet wipe for cleaning and concave embosses that are convex on the second surface of the wet wipe for cleaning a plurality of the embossed blocks are continuously arranged from a first side to a second side opposite the first side to form an embossed block row a non-embossed portion where no emboss is arranged is provided between adjacent other embossed blocks a plurality of the embossed block rows are continuously arranged from a third side orthogonal to the first side to a fourth side opposite the third side the non-embossed portion is provided so as to be 25% or more and 50% or less of the area of the wet wipe for cleaning the emboss has a gourd shape with a constricted portion at a substantially central portion in the major axis direction of an elongated elliptical shape, and the angle formed by the major axis direction of the emboss and a first direction orthogonal to the first side is 5° or more and 45° or less the convex emboss is arranged so that at least one exists on a straight line extending perpendicularly from an arbitrary point on the third side to the fourth side, and the concave emboss is arranged so that at least one exists on a line extending from an arbitrary point on the third side to the fourth side It is characterized by this.

[0007] The invention according to claim 2 is the wet sheet for cleaning according to claim 1, The chemical solution is characterized by containing 8.00% to 12.00% by mass of ethanol.

Effect of the Invention

[0012] According to the present invention, the wiping performance of the wet sheet for cleaning against oil stains and liquid stains can be improved.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Best Mode for Carrying Out the Invention

[0014] Hereinafter, with reference to the drawings, a wet sheet 100 for cleaning, which is an embodiment of the present invention, will be described. However, the technical scope of the present invention is not limited to the illustrated examples, and is determined based on the description in the claims. In the following, as shown in FIG. 1, the front-rear, left-right, up-down, X-direction, Y-direction, and Z-direction will be defined and described. Also, in this specification, "~" is used in the sense of including the numerical values described before and after it as the lower limit value and the upper limit value.

[0015] [Explanation of the Configuration] First, the configuration of the wet sheet 100 for cleaning will be described.

[0016] [(1) State during Use] As shown in FIG. 1, the wet sheet 100 for cleaning is, for example, a sheet impregnated with a chemical solution on a base paper sheet, which is detachably attached to a cleaning tool 200 including a rectangular flat plate-shaped head portion 201 and a handle portion 202 attached to the upper surface of the head portion 201, and is used for floor cleaning. Here, the base paper sheet refers to the state before the wet sheet 100 for cleaning is impregnated with the chemical solution.

[0017] The wet sheet 100 for cleaning is formed in a rectangular shape as shown in FIG. 2, covers the bottom surface of the head portion 201 of the cleaning tool 200 to form a cleaning surface, is bent along a fold line S along the longitudinal edge portion 201a of the head portion 201 of the cleaning tool 200, and is locked to the upper surface of the head portion 201 to be in a state of being attached to the cleaning tool 200. Note that the longitudinal edge portion 201a refers to the edge portion along the longitudinal direction of the head portion 201. That is, it refers to the two longer edge portions among the four edge portions of the rectangular head portion 201.

[0018] [(2) Base Paper Sheet] The base paper sheet is a non-woven fabric produced by bonding between predetermined fibers by well-known techniques such as spunlace, air-through, airlaid, point bond, spunbond, and needle punch.

[0019] Specifically, as the base paper sheet, for example, a non-woven fabric produced by mixing hydrophilic fibers and hydrophobic fibers and then bonding these fibers is used.

[0020] [a Hydrophilic fibers] As the hydrophilic fibers, natural fibers such as cotton, pulp, and hemp, and regenerated fibers such as rayon and cupra can be used. However, from the viewpoint of maintaining water retention, it is preferable to use pulp, rayon, polypropylene spunbond fiber (PPSB), etc. Moreover, the blending ratio of the hydrophilic fibers in the fibers constituting the base paper sheet is preferably 40% by mass to 80% by mass.

[0021] [b Hydrophobic fibers] Examples of the hydrophobic fibers include polyolefin fibers such as polyethylene (PE), polypropylene (PP), and polyvinyl alcohol, polyester fibers such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), and acrylic fibers. These can be used alone or in combination of two or more. Examples of the composite fiber of two or more types include a core-sheath type having a resin with a relatively low melting point (low melting point resin) in the sheath part and a resin with a relatively high melting point (high melting point resin) in the core part, and a side-by-side type in which the low melting point resin and the high melting point resin are arranged in a predetermined direction. Moreover, the blending ratio of the hydrophobic fibers in the fibers constituting the base paper sheet is preferably 20% by mass to 60% by mass.

[0022] [c Basis weight] The basis weight of the base paper sheet is preferably 50 to 100 g / m 2 from the viewpoint of achieving both the dirt holding ability and the flexibility of the sheet. The basis weight refers to the grammage measured according to JIS P8124:2011 (the same shall apply hereinafter).

[0023] [d CNF] Cellulose nanofibers (CNF) can be added to the base paper sheet. CNF refers to fine cellulose fibers obtained by defibrating pulp fibers, and generally refers to cellulose fibers containing cellulose fine fibers with a fiber width in the nano size range (1 nm to 1000 nm). However, the average fiber width is preferably 100 nm or less. The average fiber width is calculated using, for example, the number average, median, and mode diameter (most frequent value) of a certain number.

[0024] CNF may be uniformly impregnated in the thickness direction of the base paper sheet, but it is preferably in a state where the CNF content gradually increases from the center in the thickness direction of the base paper sheet toward the front and back surfaces. This is because the wet sheet 100 for cleaning is less likely to tear even when the cleaning surface or the like is strongly rubbed.

[0025] [(a) Pulp fibers usable for CNF] Examples of pulp fibers that can be used for the production of CNF include chemical pulps such as hardwood pulp (LBKP) and softwood pulp (NBKP), bleached thermomechanical pulp (BTMP), stone ground pulp (SGP), pressurized stone ground pulp (PGW), refiner ground pulp (RGP), chemiground pulp (CGP), thermoground pulp (TGP), ground pulp (GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), refiner mechanical pulp (RMP), etc. mechanical pulps, waste paper pulp produced from tea waste paper, kraft envelope waste paper, magazine waste paper, newspaper waste paper, flyer waste paper, office waste paper, cardboard waste paper, high-quality waste paper, Kent waste paper, imitation waste paper, deed waste paper, toilet paper waste paper, etc., deinked pulp (DIP) obtained by deinking waste paper pulp, etc. These may be used alone or in combination of multiple types as long as the effects of the present invention are not impaired.

[0026] [(b) Defibrating method of CNF] Examples of the fibrillation method used for the production of CNF include mechanical methods such as the high-pressure homogenizer method, the microfluidizer method, the grinder grinding method, the bead mill cryogenic grinding method, and the ultrasonic fibrillation method, but are not limited to these methods. Note that CNF that has been subjected only to mechanical treatment (not modified) by the above fibrillation method or the like, that is, CNF without functional group modification, has high thermal stability compared to those modified with functional groups such as phosphate groups and carboxymethyl groups, and thus can be used in a wider range of applications. However, it is also possible to use CNF modified with functional groups such as phosphate groups and carboxymethyl groups in the present invention. In addition, for example, chemical treatment such as carboxymethylation or enzyme treatment may be performed on pulp fibers that have been subjected to a fibrillation treatment by a mechanical method. Examples of CNF subjected to chemical treatment include iCNF (individualized CNF) (single nanocellulose) having a diameter of 3 nm to 4 nm, such as TEMPO-oxidized CNF, phosphoric acid esterified CNF, and phosphorous acid esterified CNF. Moreover, CNF subjected only to chemical treatment or enzyme treatment, or CNF subjected to chemical treatment or enzyme treatment and then subjected to a fibrillation treatment by a mechanical method may also be used.

[0027] [(3) Chemical solution] As the chemical solution impregnated into the base paper sheet as described above, a weakly alkaline solution with a hydrogen ion index (pH) of 8.0 to 9.0, containing 0.05% by mass to 0.15% by mass of polyoxyethylene alkyl ether (AE), 5.00% by mass to 15.00% by mass of ethanol, preferably 8.00% by mass to 12.00% by mass, is used.

[0028] In addition, the chemical solution is impregnated in an amount of 150% by mass to 450% by mass, preferably 180% by mass to 350% by mass, based on the mass of the base paper sheet when it is dried. The chemical solution is impregnated into the dried base paper sheet and is to be released from the cleaning surface when the wet sheet 100 for cleaning is used.

[0029] [(4) Embossing] As shown in FIGS. 1 and 2, on the cleaning wet sheet 100, in order to improve the wiping performance against the dirt on the surface to be cleaned by causing unevenness on the sheet and scraping off the dirt by the unevenness, an emboss 20 which is a portion where the sheet is compressed in the Z direction is arranged. As shown in FIG. 2, for example, the emboss 20 is formed in a so-called gourd shape which is an elongated elliptical shape with a short length and a narrow width in one direction in plan view and has a constricted portion at substantially the center in the major axis direction. The shape of the emboss 20 is not limited to this, and for example, various shapes such as polygons or a combination of each shape may be used, but from the viewpoint of improving the scraping property of dirt, it is preferable to have such a gourd shape.

[0030] Such an emboss 20 can be formed, for example, by thermal embossing under the conditions of a temperature of 80°C to 200°C and an embossing pressure of 0.2 MPa to 1.0 MPa. When forming the emboss 20 by thermal embossing, as the convex embossing roll, at least the outer peripheral surface can be made of carbon steel, stainless steel, or a cured resin such as polypropylene or ABS (Acrylonitrile Butadiene Styrene) resin, etc. Among them, from the viewpoints of durability and heat resistance, it is preferable to use the one made of stainless steel. Also, when performing embossing by thermal embossing, it is preferable to perform it before the step of impregnating the cleaning wet sheet 100 with a chemical solution from the viewpoint of ease of imparting the uneven shape.

[0031] [a convex emboss, a concave emboss] As the emboss 20, a convex emboss 21 which is convex on the upper side in the Z direction (the first surface side of the cleaning wet sheet 100) and a concave emboss 22 which is convex on the lower side (the second surface side of the cleaning wet sheet 100) (that is, concave on the upper side in the Z direction) are formed. In each figure, the convex emboss 21 is shown by a solid line and the concave emboss 22 is shown by a broken line.

[0032] The convex emboss 21 has a major axis direction of 5 mm to 10 mm, preferably 6 mm to 8 mm, a minor axis direction orthogonal to the major axis direction of 2 mm to 5 mm, preferably 3 mm to 4 mm, and is formed in the Z direction (height from the middle part (described later)) of 0.5 mm to 2 mm, preferably 0.7 mm to 1.5 mm. The concave emboss 22 is formed in a shape that is upside down with respect to the convex emboss 21 in a cross-sectional view and has substantially the same shape, and is formed in a shape that protrudes downward in the Z direction.

[0033] [b Middle part] A middle part is formed between the embosses 20 formed on the cleaning wet sheet 100. Since the middle part is a portion where the emboss 20 is not formed, it is lower than the convex emboss 21 and higher than the concave emboss 22 in the Z direction.

[0034] [c Emboss pattern] In the cleaning wet sheet 100 according to the present embodiment, for example, as shown in FIG. 2, a diamond-shaped first emboss block 30 composed of a combination of a convex emboss 21 and a concave emboss 22, in which the angle formed by the first side a and the first direction (X direction in FIG. 2) orthogonal thereto and the major axis direction is 5° to 45°, preferably 15° to 35°, forms an emboss block row 31 continuously from the first side a to the second side b, and a plurality of the emboss block rows 31 are continuously arranged from the third side c to the fourth side d. In adjacent first emboss block rows 31 and second emboss block rows 31, the first emboss block 30 in the first emboss block row 31 overlaps with an adjacent second emboss block 30 in the second emboss block 31 row in the second direction (Y direction in FIG. 2) orthogonal to the first direction, and at least one convex emboss 21 and concave emboss 22 are arranged on a straight line extending perpendicularly from an arbitrary point on the third side c to the fourth side d.

[0035] [d Non-embossed part] As shown in Fig. 2, between adjacent embossed blocks 30, a non-embossed portion 40 is provided, which is a portion having fluff and where the cleaning wet sheet 100 is not compressed in the Z direction compared to the portion where the emboss 20 is formed.

[0036] The non-embossed portion 40 can be formed by designing the convex embossing roll that forms the emboss 20 so as to exclude the shape of the non-embossed portion 40, or by lightly compressing it compared to the portion where the emboss 20 is compressed to such an extent that fluff remains. By providing such a non-embossed portion 40 in an amount of 25% to 50% with respect to the area of the cleaning wet sheet 100, the generation of wiping streaks can be reduced, and the cleaning wet sheet 100 excellent in wiping performance can be obtained. Note that it is most preferable to provide the non-embossed portion 40 in an amount of 25% with respect to the area of the cleaning wet sheet 100.

[0037] When the cleaning wet sheet 100 is attached to the cleaning tool 200 for wiping cleaning, it is usually moved substantially perpendicular to the X direction or the Y direction. However, as shown in Fig. 2, when the non-embossed portion 40 is formed in a straight line, there is a possibility that wiping streaks are likely to occur depending on the angle of moving the cleaning wet sheet 100. Therefore, it is more desirable to arrange the embossed blocks 30 so that the non-embossed portion 40 does not form a straight line.

[0038] [Description of Effects] According to the cleaning wet sheet 100 of the present embodiment, as the chemical solution impregnated in the base paper sheet, a weakly alkaline one with a hydrogen ion index (pH) of 8.0 to 9.0, containing 0.05% by mass to 0.15% by mass of polyoxyethylene alkyl ether (AE) and 5.00% by mass to 15.00% by mass of ethanol is used. Thereby, since it contains a surfactant strong against oil stains and liquid stains such as polyoxyethylene alkyl ether and the ethanol content is relatively high, the oil stains can be floated, and the wiping performance against oil stains and liquid stains can be improved. In addition, since drying is relatively fast and the pH is 9 or less, the deterioration speed of the surface to be cleaned is suppressed, so the possibility of damaging the surface to be cleaned can be suppressed while improving the wiping performance against oil stains and liquid stains.

[0039] Moreover, according to the cleaning wet sheet 100 of the present embodiment, since the embossments 20 are arranged as described above, the wiping performance against dirt can be further improved due to the unevenness of the sheet, and the following effects can be obtained.

[0040] That is, usually, when the cleaning wet sheet 100 is attached to the cleaning tool 200 having the head portion 201 and wiping cleaning is performed, it is moved in the first direction (the X direction in FIG. 2) or the second direction (the Y direction in FIG. 2). However, if the convex embossments are arranged in series so as to be aligned along such a first direction or the second direction, there may be a portion on the surface to be cleaned where wiping by the convex embossments is not performed (so-called "wiping streaks"). A user who visually recognizes the wiping streaks may discard the sheet, judging that the chemical solution has dried out although the chemical solution still remains in the sheet, and may use an unnecessarily large number of sheets.

[0041] On the other hand, when the cleaning wet sheet 100 having the embossment pattern as described above and arranged such that at least one convex embossment 21 exists on a straight line extending perpendicularly from an arbitrary point on the third side c to the fourth side d is attached, when wiping cleaning is performed at least in the second direction (the Y direction in FIG. 2), the convex embossments 21 overlap each other to have an overlapping margin, so the generation of wiping streaks can be reduced.

[0042] Further, without providing the embossing 20 on the entire surface of the wet wipe 100 for cleaning, by providing the non-embossed portion 40 between each embossing block 30 in an amount of 25% to 50% based on the area of the wet wipe 100 for cleaning, when wiping and cleaning with the wet wipe 100 for cleaning, the convex embossing 21 protruding more than the non-embossed portion 40 receives a greater pressure, so that the releasability of the chemical liquid is improved and the generation of wiping streaks can be further reduced. Further, since the convex embossing 21 receives a greater pressure, the scraping property of the convex embossing 21 is improved, and dust tends to accumulate in the non-embossed portion 40, so that the dust collection property can be enhanced. Also, even if the scraping property of the convex embossing 21 and the dust collection property of the wet wipe 100 for cleaning are enhanced, an increase in wiping resistance can be suppressed to the extent that the non-embossed portion 40 is less likely to contact the surface to be cleaned due to the convex embossing 21.

[0043] Further, the embossing block 30 is in a rhomboid shape composed of the embossing 20 such that the angle formed by the first direction and the major axis direction is 5° to 45°, preferably 15° to 35°. When a plurality of embossing block rows 31 continuously arranged from the first side a to the second side b are continuously arranged from the third side c to the fourth side d, the embossing blocks 30 are necessarily arranged so as to be displaced with respect to the first direction of the wet wipe 100 for cleaning. Also, when the user performs wiping and cleaning, a margin is created in the angle at which the wet wipe 100 for cleaning is moved.

[0044] Further, since the embossing 20 is in an elliptical shape and has a constricted portion at approximately the center in the major axis direction, the scraping performance of dirt can be enhanced.

[0045] [3 Modification Example] Hereinafter, modification examples of the above embodiment will be described.

[0046] [(1) Adoption of a Sheet with a Multilayer Structure] In the above description, the case where a single-layer nonwoven fabric formed by mixing hydrophilic fibers and hydrophobic fibers is used as the base paper sheet has been described. Instead of this, a sheet having a multilayer structure including a hydrophilic fiber layer mainly composed of hydrophilic fibers and a hydrophobic fiber layer mainly composed of hydrophobic fibers may be used.

[0047] Specifically, for example, a three-layer structure may be adopted in which the surface layers on both sides are hydrophobic fiber layers mainly composed of hydrophobic fibers, and the middle layer is a hydrophilic fiber layer mainly composed of hydrophilic fibers. In the boundary region between the fibers of the hydrophobic fiber layer and the fibers of the hydrophilic fiber layer, the fibers of each layer may be configured to be intertwined with each other.

[0048] In this case, the chemical solution impregnated in the hydrophilic fiber layer is less likely to be released to the surface to be cleaned adjacent to the hydrophobic fiber layer, and the chemical solution can be selectively released to the surface to be cleaned, and the release of the chemical solution that is not effective for cleaning can be suppressed. In addition, by configuring the hydrophobic fibers and the hydrophilic fibers to be intertwined with each other, the air held in the intertwined portions can further enhance the retention of the chemical solution.

[0049] [(2) Change of embossing pattern] In the above description, the case where the embossing block 30 composed of a combination of the convex embossing 21 and the concave embossing 22 is formed on the cleaning wet sheet 100 has been exemplified. However, the embossing block 30 only needs to include at least the convex embossing 21. However, by providing the concave embossing 22, the cleaning wet sheet 100 can be turned over and used, and the cleaning area can be further expanded, which is preferable.

[0050] In FIGS. 1 and 2, the diamond-shaped embossing block 30 composed of the embossing 20 with the angle between the first direction and the major axis direction being 5° to 45°, preferably 15° to 35° has been exemplified. However, the shape of the embossing block 30 is not limited to this. For example, the embossing block 30 composed of the embossing 20 with the angle between the first direction and the major axis direction being 0° or 90° may also be used.

[0051] In FIGS. 1 and 2, the convex embossments 21 and concave embossments 22 in each emboss block 30 are exemplified as having the same angle between the major axis direction and the first direction. However, the present invention is not limited to this. As shown in FIG. 3, the orientation of the major axis direction of the convex embossments 21 and concave embossments 22 in the first emboss block 30 may be arranged to be different from the orientation of the major axis direction of the convex embossments 21 and concave embossments 22 in the second emboss block 30 adjacent to the first emboss block 30. Also, the convex embossment 21 and the concave embossment 22 in the first emboss block 30 may be arranged such that their angles are different from each other.

[0052] In each figure, the first side a and the second side b are the short sides of the cleaning wet sheet 100, and the third side c and the fourth side d are the long sides of the cleaning wet sheet 100. However, the present invention is not limited to this.

[0053] In each figure, the convex embossment 21 and the concave embossment 22 are both substantially the same gourd shape in plan view. However, the convex embossment 21 and the concave embossment 22 may have different shapes.

[0054] However, in any of the above emboss patterns, it is preferable that the convex embossment 21 and the concave embossment 22 in the cleaning wet sheet 100 are arranged to be substantially symmetric between the first surface and the second surface. By doing so, the first surface and the second surface of the cleaning wet sheet 100 have approximately the same cleaning function, and the cleaning area per sheet can be increased.

Example

[0055] Next, the evaluation results of the examples and comparative examples of the present invention will be described. Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited thereto.

[0056] [Comparison by Composition of Chemical Solution] First, the results of evaluating the difference in wiping performance against stains due to the composition of the chemical solution impregnated in the base paper sheet will be described.

[0057] [(1) Sample preparation] Wet wipes for cleaning of the following Examples and Comparative Examples were prepared.

[0058] [a Example 1-1] As the base paper sheet, a non-woven fabric (rectangular shape with a long side of 300 mm and a short side of 200 mm) made of 40 mass% PET fiber, 40 mass% rayon fiber, and 20 mass% PP / PE binder and produced by bonding with spunlace, with a basis weight of 60 g / m 2 was used. Note that no embossing process was applied. As the chemical solution impregnated in the base paper sheet, one containing 10.00 mass% ethanol and 0.10 mass% polyoxyethylene alkyl ether (AE) (the remaining components being purified water) and having a pH of 8.8 was used, and it was impregnated at 200 mass% with respect to the mass of the base paper sheet when dry.

[0059] [b Comparative Example 1-1] As the chemical solution impregnated in the base paper sheet, the chemical solution described as Example 1 in Patent Document 1 was used. Other points were the same as in Example 1-1. Note that the specific components of the chemical solution used are as follows. Purified water: 99.434% Benzalkonium chloride 50% aqueous solution: 1.0×10 -1 % (Benzalkonium chloride: 5.0×10 -2 %) Cetylpyridinium chloride: 3.0×10 -2 % Polyaminopropyl biguanide 20% aqueous solution: 1.0×10 -1 % (Polyaminopropyl biguanide: 2.0×10 -2 %) Grapefruit seed extract: 1.0×10 -2 % Phenoxyethanol: 3.0×10-1 % Citric acid: 5.0×10 -3 % Sodium citrate: 1.0×10 -3 % Aloe extract: 1.0×10 -2 % Glycerin: 1.0×10 -2 %

[0060] [(2) Test content] Using the wet wipes for cleaning according to the above Examples and Comparative Examples, the following stain removal test was conducted.

[0061] [a Creation of pseudo stains] At the center of the long side of a rectangular stainless steel plate with a long side of 320 mm and a short side of 180 mm, the following two types of pseudo stains were attached along the short side direction. In both cases, after dropping 0.5 ml, it was dried at 60° for 1 hour.

[0062] [(a) Pseudo stain 1: Cafe au lait] It is assumed to be a liquid stain. Specifically, "Mild Cafe au Lait" manufactured by Ezaki Glico Co., Ltd. was used.

[0063] [(b) Pseudo stain 1: Curry] It is assumed to be an oil stain. Specifically, "Curry Chef Beef Curry" manufactured by Ezaki Glico Co., Ltd. was used.

[0064] [b Conducting the wiping test] The wiping test was conducted by the following method.

[0065] (i) Place the sheet of Example 1-1 or Comparative Example 1-1 so that the long side of the sheet is along the short side direction of the stainless steel plate at the right end of the stainless steel plate (one end of the long side direction of the stainless steel plate located on the right side as seen by the tester). (ii) Place a rubber plate (rectangular with a long side of 100 mm and a short side of 100 mm, mass 275 g) on the sheet so that the long side of the rubber plate is along the short side of the stainless steel plate. (iii) Push the weight horizontally and move it 200 mm together with the sheet in the direction of the left end of the stainless steel plate (the other end opposite to the above-mentioned one end in the long side direction of the stainless steel plate, which is located on the left side as viewed from the tester). The time required for the movement is 4 seconds. (iv) Push the weight horizontally and move it 200 mm together with the sheet in the direction of the right end of the stainless steel plate. The time required for the movement is 4 seconds.

[0066] Repeat the steps (iii) and (iv) 25 times, and after each time, check the state of the pseudo stain on the stainless steel plate. Hereinafter, one execution of the steps (iii) and (iv) is referred to as one wiping. In addition, the same test was conducted twice.

[0067] [(3) Test Results] The test results are shown in Table I. Regarding the test results, the number of wiping times until each stain falls off (the state where the stain cannot be visually recognized) is described.

[0068]

Table 1

[0069] [(4) Evaluation] Comparing the results of the wiping test according to Example 1-1 with the results of the wiping test according to Comparative Example 1-1, for both curry (oil stain) and caffeol (liquid stain), in both Test 1 and Test 2, the number of wiping times required until the stain falls off is less for Example 1-1. From this, it can be seen that by using a chemical solution impregnated in the wet sheet for cleaning, which is weakly alkaline with a hydrogen ion index (pH) of 8.0 to 9.0 and contains 0.05 mass% to 0.15 mass% of polyoxyethylene alkyl ether (AE) and 5.00 mass% to 15.00 mass% of ethanol, the wiping performance of the wet sheet for cleaning against oil stains and liquid stains can be improved.

[0070] [Comparison by the configuration of the two embossings] Subsequently, the results of evaluating the effects on the wiping streak amount, wiping amount, and wiping resistance according to the pattern of the embossing formed on the cleaning wet sheet will be described.

[0071] [(1) Sample preparation] The test sheets of the following examples and comparative examples were prepared.

[0072] [a Example 2-1: 25% non-embossed part] Basis weight 40 g / m 2 ~50 g / m 2 Two hydrophobic fiber layers composed of 80% by mass of PET and 20% by mass of PP / PE binder, and a basis weight of 40 g / m 2 ~50 g / m 2 One hydrophilic fiber layer composed of 70% by mass of pulp and 30% by mass of PPSB were prepared, and the two sides of the hydrophilic fiber layer were entangled by the water entanglement method so as to be sandwiched by the hydrophobic fiber layers, and then cut into 300 mm × 200 mm to prepare one base paper sheet. Then, thermal embossing was performed under the conditions of a temperature of 95°C and an embossing pressure of 0.4 MPa as follows.

[0073] That is, as shown in FIG. 2, a diamond-shaped first embossed block 30 composed of a combination of a gourd-shaped convex emboss 21 and a concave emboss 22, in which the angle formed by the first direction (X direction in FIG. 2) and the major axis direction is 30°, is continuously arranged in a plurality from the first side a to the second side b facing the first side a. An embossed block row 31 is continuously arranged in a plurality from the third side c to the fourth side d. At this time, in adjacent first embossed block rows 31 and second embossed block rows 31, the first embossed blocks 30 in the first embossed block row 31 overlap with adjacent second embossed blocks 30 in the second embossed block row 31 in the first direction, and at least one convex emboss 21 exists on a line vertically extended from an arbitrary point on the third side c to the fourth side d. The emboss 20 is arranged so that a non-embossed portion 40 is provided between the embossed blocks 30 at 25.0% of the area of the base paper sheet.

[0074] Further, a chemical solution containing an aqueous cleaning agent, a preservative, a disinfectant, and alcohol was impregnated into the base paper sheet after heat embossing at 300% by mass based on the mass of the base paper sheet when it was dry.

[0075] [b Example 2-2: Non-embossed portion 37.5%)] As shown in FIG. 4A, the non-embossed portion 40 was provided to be 37.5% of the area of the base paper sheet. Other points are the same as those in Example 2-1.

[0076] [c Example 2-3: Non-embossed portion 50%)] As shown in FIG. 4B, the non-embossed portion 40 was provided to be 50.0% of the area of the base paper sheet. Other points are the same as those in Example 2-1.

[0077] [d Comparative Example 2-1: Non-embossed portion 0%, arranged in series] As shown in FIG. 4C, gourd-shaped convex embossments and concave embossments with the major axis direction parallel to the first direction were alternately arranged on the entire surface of the base paper sheet to create a test sheet having no non-embossed portion 40. Other points are the same as in Example 2-1.

[0078] [e Comparative Example 2-2: 0% non-embossed portion, zigzag] A gourd-shaped embossment is provided with a plurality of first convex embossments and second convex embossments having different major axis directions. The first convex embossments adjacent to each other in the minor axis direction are arranged such that a part of both first convex embossments overlaps in the minor axis direction and is displaced in the major axis direction, and the second convex embossments adjacent to each other in the minor axis direction are arranged such that a part of both second convex embossments overlaps in the minor axis direction and is displaced in the major axis direction. Such a plurality of first convex embossments and second convex embossments are adjacently arranged so that the major axis directions are substantially perpendicular to each other, and are continuously arranged from the first side a of the base paper sheet toward the second side b opposite to the first side a. Also, concave embossments were arranged in the same embossment pattern as the convex embossments so as to alternate with the convex embossments, and a test sheet having no non-embossed portion 40 as shown in FIG. 4D was created. Other points are the same as in Example 2-1.

[0079] [f Comparative Example 2-3: 100% non-embossed portion] A test sheet having only the non-embossed portion 40 was created without performing embossing. Other points are the same as in Example 2-1.

[0080] [(2) Test content] The wet wipes for cleaning of Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-3 were respectively attached to a cleaning tool having a rectangular flat head portion of 250 mm × 100 mm to create wipes with wet wipes for cleaning of Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-3, and Tests 1 to 3 below were performed using the wipes with wet wipes for cleaning.

[0081] [a Test 1: Swipe streak test] (i) Place the wiper with a wet sheet on which weights are placed so that the total weight is 400 g on the right end of the blackboard (one end in the long side direction of the blackboard, located on the right side as seen by the tester) with the head facing straight. For the blackboard, a wooden wall-mounted blackboard (size: 450 mm × 300 mm) manufactured by BUNMARU CO., LTD. was used. (ii) Push the weights and the wiper with the wet sheet from the right end to the left end of the blackboard (the other end opposite to the above-mentioned one end in the long side direction of the blackboard, located on the left side as seen by the tester) and move it 300 mm. (iii) Regarding the generated wiping streaks, visually evaluate them as ○ when there are almost no wiping streaks on the cleaning surface (the wet area is about 90% - 100% of the entire cleaning surface), △ when there are a few wiping streaks (the wet area is about 80% - 90% of the entire cleaning surface), and × when there are many wiping streaks (the wet area is 80% or less of the entire cleaning surface).

[0082] [b Test 2: Wiping Performance Test] (i) After dropping 15 ml of artificial dirt formulated at a ratio of beef tallow: olive oil: chloroform: fluorescent paint = 12.5:12.5:74.4:0.6 (mass ratio) on a stainless steel plate of 480 mm × 320 mm and spreading it, dry it with a hot air dryer (temperature 60°C) for 5 minutes, and measure the weight of the stainless steel plate. (ii) Place the wiper with a wet sheet on which weights are placed so that the total weight is 500 g on the right end of the stainless steel plate (one end in the long side direction of the stainless steel plate, located on the right side as seen by the tester) with the head facing straight. (iii) Push and move the weights and the wiper with the wet sheet from the right end to the left end of the stainless steel plate (the other end opposite to the above-mentioned one end in the long side direction of the stainless steel plate, located on the left side as seen by the tester), dry only the stainless steel plate again with a hot air dryer (temperature 60°C) for 5 minutes, and measure the weight. (iv) Calculate the wiping amount of each wet sheet for cleaning from the difference between the weight of the stainless steel plate before the test measured in (i) and the weight of the stainless steel plate after the test measured in (iii). (v) Perform the operations in (i) - (iv) twice and calculate the average value of the wiping amount.

[0083] [c Test 3: Rubbing Resistance Test] (i) Place the wiper with a wet sheet on which weights are placed so that the total weight is 500 g on the composite flooring with the head facing forward. The composite flooring used was the Home Floor (product number: HF-100N) manufactured by DIY Century Co., Ltd. (ii) Drill a hole in the head connecting part of the wiper body and attach a push-pull gauge (DS2-200N manufactured by IMADA Co., Ltd.) to the hole. (iii) Measure the maximum resistance value when the wiper with a wet sheet to which the push-pull gauge is attached is pulled 50 cm. (iv) Perform the operation in (iii) 5 times and calculate the average value of the rubbing resistance.

[0084] [(3) Test Results] The results of Test 1 to Test 3 are shown in Table II.

[0085] [Table 2]

[0086] [(4) Evaluation] Comparing the results of Test 1, it can be seen that Examples 2-1 to 2-3 provided with the non-embossed portion 40 can reduce the generation of wiping streaks compared to Comparative Examples 2-1 and 2-2 without the non-embossed portion 40. This is presumably because the pressure applied to the convex emboss 21 increases due to the provision of the non-embossed portion 40, and the release property of the chemical solution is enhanced. On the other hand, comparing Examples 2-1 to 2-3 and Comparative Example 2-3, although slightly, the generation of wiping streaks increased as the ratio of the non-embossed portion 40 increased. This is presumably because as the ratio of the non-embossed portion 40 increases, the number of convex embosses 21 decreases accordingly, the contact area with the blackboard decreases, and the release property of the chemical solution decreases.

[0087] Also, when comparing the results of Test 2, Examples 2-1 to 2-3 with the non-embossed portion 40 provided show a larger wiping amount compared to Comparative Examples 2-1 and 2-2 without the non-embossed portion 40. Thus, it can be seen that the wiping performance has been improved. On the other hand, when comparing Examples 2-1 to 2-3, it can be seen that Example 2-1 with 25% of the non-embossed portion 40 can wipe off the most dirt, and the wiping amount of dirt decreases as the non-embossed portion 40 increases. As described above, this is presumably because as the ratio of the non-embossed portion 40 increases, the number of convex embossments 21 decreases accordingly, reducing the chemical solution release property and the dirt scraping property.

[0088] Also, when comparing the results of Test 3, only in Comparative Example 3-3 without the embossment 20 on the entire surface did the wiping resistance increase, but there was no significant difference in the wiping resistance among Comparative Examples 2-1 and 2-2 without the non-embossed portion 40 and Examples 2-1 to 2-3 with the non-embossed portion 40. This is presumably because since the non-embossed portion 40 is less likely to be grounded to the surface to be cleaned, the wiping resistance across the entire cleaning wet sheet 100 does not change much.

Explanation of Reference Numerals

[0089] 100 Cleaning wet sheet 20 Embossment 21 Convex embossment 22 Concave embossment 30 Embossment block 31 Embossment block row 40 Non-embossed portion 200 Cleaning tool 201 Head portion a First side b Second side c Third side d Fourth side

Claims

1. A wet sheet for cleaning in which a base paper sheet is impregnated with a chemical solution, wherein the chemical solution has a hydrogen ion exponent of 8.0 to 9.0 and contains 0.05% by mass to 0.15% by mass of polyoxyethylene alkyl ether and 5.00% by mass to 15.00% by mass of ethanol, the wet sheet for cleaning is provided with a diamond-shaped embossed block formed by a plurality of convex embosses that are convex on the first surface of the wet sheet for cleaning and concave embosses that are convex on the second surface of the wet sheet for cleaning, a plurality of the embossed blocks are continuously arranged from a first side to a second side opposite to the first side to form an embossed block row, a non-embossed portion where no emboss is arranged is provided between adjacent other embossed blocks, a plurality of the embossed block rows are continuously arranged from a third side orthogonal to the first side to a fourth side opposite to the third side, the non-embossed portion is provided so as to be 25% or more and 50% or less of the area of the wet sheet for cleaning, the emboss has a gourd shape with a constricted portion at a substantially central portion in the major axis direction of an elongated elliptical shape, and an angle formed by the major axis direction of the emboss and a first direction orthogonal to the first side is 5° or more and 45° or less, the convex emboss is arranged so that at least one exists on a straight line extending perpendicularly from an arbitrary point on the third side to the fourth side, and the concave emboss is arranged so that at least one exists on a line extending from an arbitrary point on the third side to the fourth side. A wet sheet for cleaning characterized by this.

2. The wet sheet for cleaning according to claim 1, wherein the chemical solution contains 8.00% by mass to 12.00% by mass of ethanol.

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