Cleaning wipes

Abstract

To improve dirt wiping-off performance of a cleaning wet sheet.SOLUTION: In a cleaning wet sheet 100 obtained by impregnating a liquid medicine into a base paper sheet, the base paper sheet includes modified cross-section fibers F whose cross sections have a shape where a plurality of projections F1 and a plurality of recesses F2 are alternately arranged.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] When cleaning floors and the like, it is convenient to use a dedicated disposable sheet. Thus, an invention of a cleaning sheet used to clean various surfaces is known (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-216843 A Summary of the Invention [Problem to be solved by the invention]

[0004] For such cleaning sheets, it is important to improve the wiping performance for removing dirt from the surface to be cleaned. In the past, the ability to wipe off dirt was improved by, for example, impregnating the sheet with a special chemical solution, but there was a demand for further improvement in wiping performance.

[0005] An object of the present invention is to improve the wiping performance of a wet cleaning sheet against dirt. [Means for solving the problem]

[0006] In order to solve the above problem, the invention described in claim 1 comprises: A wet cleaning sheet in which a base paper sheet is impregnated with a chemical solution, The base paper sheet includes modified cross-section fibers having a cross-section in which a plurality of convex portions and a plurality of concave portions are alternately arranged. fruit, The chemical solution has a hydrogen ion exponent of 8.0 to 9.0, and contains 0.01% by mass to 0.25% by mass of polyoxyethylene alkyl ether, 1.00% by mass to 5.00% by mass of ethanol, and 1.00% by mass to 5.00% by mass of diethylene glycol monobutyl ether. It is characterized by:

[0007] The invention described in claim 2 is the cleaning wet sheet described in claim 1, The base paper sheet includes hydrophilic fibers and hydrophobic fibers, The hydrophobic fiber includes the modified cross section fiber.

[0008] The invention described in claim 3 is the cleaning wet sheet described in claim 2, The modified cross-section fiber is a polyethylene terephthalate fiber.

[0010] Claim 4 The invention described in claim 1 3 The cleaning wet sheet according to any one of claims 1 to 5, The first surface of the wet cleaning sheet is provided with an embossing block having a plurality of convex embossments, a plurality of the embossing blocks are continuously arranged from a first side to a second side opposite to the first side to form an embossing block row; a non-embossed portion where the embossing is not arranged between adjacent ones of the embossing blocks; the embossed block rows are arranged continuously from a third side perpendicular to the first side to a fourth side opposite to the third side, The non-embossed portion is provided so as to occupy 25% or more and 50% or less of the area of ​​the cleaning wet sheet, The protruding embossments are characterized in that at least one of them is disposed on a straight line extending perpendicularly from an arbitrary point on the third side to the fourth side.

[0011] Claim 5 The invention described in claim 4 The cleaning wet sheet according to claim 1, The second surface of the cleaning wet sheet is provided with a concave embossment, which is a convex embossment, The embossing block is composed of a combination of a plurality of the convex embossments and the concave embossments, The recessed embossments are characterized in that at least one of them is disposed on a line extending from an arbitrary point on the third side to the fourth side.

[0012] Claim 6 The invention described in claim 4 or 5 The cleaning wet sheet according to claim 1, an angle between a major axis direction of the embossment and a first direction perpendicular to the first side is 5° or more and 45° or less; The embossing block is characterized in that it is rhombus-shaped.

[0013] Claim 7 The invention described in claim 4 from 6 The cleaning wet sheet according to any one of claims 1 to 5, The embossment is elliptical in shape and has a constricted portion at approximately the center in the major axis direction. Effect of the Invention

[0014] According to the present invention, the wiping performance of a wet cleaning sheet against dirt can be improved. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view of a cleaning tool to which a wet cleaning sheet according to an embodiment of the present invention is attached. [Diagram 2] FIG. 1 is a plan view showing a wet cleaning sheet according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a cross-sectional view of a modified cross-section fiber included in the wet cleaning sheet according to the embodiment of the present invention, cut along a cross section perpendicular to the longitudinal direction of the fiber. [Figure 4] FIG. 11 is a plan view showing a modified example of a wet cleaning sheet. [Figure 5A] FIG. 2 is a plan view showing an embossing pattern according to an embodiment of the present invention. [Figure 5B]FIG. 2 is a plan view showing an embossing pattern according to an embodiment of the present invention. [Figure 5C] FIG. 11 is a plan view showing an embossed pattern according to a comparative example. [Figure 5D] FIG. 11 is a plan view showing an embossed pattern according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, a wet cleaning sheet 100 according to an embodiment of the present invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited to the illustrated examples, and is determined solely based on the description of the claims. In the following description, the front-back, left-right, up-down, X-direction, Y-direction, and Z-direction are defined as shown in Fig. 1. In addition, in this specification, "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0017] [1 Configuration Description] First, the configuration of the wet cleaning sheet 100 will be described.

[0018] [(1) Condition when in use] 1, the cleaning wet sheet 100 is a base paper sheet impregnated with a chemical solution, which is used for cleaning floor surfaces by being replaceably attached to a cleaning tool 200 having, for example, a rectangular, flat head part 201 and a handle part 202 attached to the upper surface of the head part 201. Note that the base paper sheet here refers to the state of the cleaning wet sheet 100 before it is impregnated with the chemical solution.

[0019] The cleaning wet sheet 100 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, and is folded at a fold line S along the longitudinal edge portion 201a of the head portion 201 of the cleaning tool 200 to be engaged with the upper surface of the head portion 201, thereby being attached to the cleaning tool 200. The long edges 201a refer to edges along the long direction of the head portion 201. In other words, they refer to the two longer edges of the four edges of the rectangular head portion 201.

[0020] [(2) Base paper sheet] The base paper sheet is a nonwoven fabric produced by bonding selected fibers together by known techniques such as spunlace, air-through, airlaid, point bond, spunbond, needle punch, and the like.

[0021] Specifically, the base paper sheet is made of a nonwoven fabric produced by mixing hydrophilic fibers and hydrophobic fibers and then bonding these fibers.

[0022] [a Hydrophilic fiber] As hydrophilic fibers, natural fibers such as cotton, pulp, and hemp, and regenerated fibers such as rayon and cupra can be used, but from the viewpoint of maintaining water retention, it is preferable to use pulp, rayon, polypropylene spunbond fiber (PPSB), etc. The blending ratio of hydrophilic fibers in the fibers constituting the base-paper sheet is preferably 40% by mass to 80% by mass.

[0023] [b Hydrophobic fiber] Hydrophobic fibers include polyolefin fibers such as polyethylene (PE), polypropylene (PP), and polyvinyl alcohol, polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). Lev Examples of the composite fibers include polyester fibers such as polybutadiene (PBT), acrylic fibers, etc., which can be used alone or in combination of two or more. Examples of composite fibers of two or more types include a core-sheath type in which a resin with a relatively low melting point (low melting point resin) is used as the sheath and a resin with a relatively high melting point (high melting point resin) is used as the core, and a side-back type in which a low melting point resin and a high melting point resin are arranged in parallel in a predetermined direction. The blending ratio of hydrophobic fibers in the fibers constituting the base-paper sheet is preferably 20% by mass to 60% by mass.

[0024] In addition, the hydrophobic fiber used is a modified cross-section fiber, which means a fiber whose cross section, when cut perpendicular to the longitudinal direction of the fiber, is not circular like ordinary fibers. It is not necessary that all the hydrophobic fibers are modified cross-section fibers, and when two or more types of hydrophobic fibers are used in combination, at least one of them may be modified cross-section fibers. However, it is preferable that at least 20 mass % of the hydrophobic fibers are modified cross-section fibers.

[0025] Specifically, the modified cross-section fiber used is a modified cross-section fiber F having a trefoil cross section as shown in Fig. 3. The trefoil shape here refers to a shape in which three convex portions F1 that are convex toward the outer surface of the fiber and three concave portions F2 that are concave toward the center of the fiber are alternately arranged as shown in Fig. 3, and is not limited to a "leaf" shape. In this case, the modified cross section fiber preferably has a fiber thickness of 0.8 dtex to 6.0 dtex and a fiber length of 30 mm to 80 mm. As the modified cross-section fiber, it is preferable to use a PET fiber having a cross-sectional shape as shown in FIG.

[0026] In addition, as the modified cross-section fiber, one having a trilobal cross-section as shown in FIG. 3 is preferable, but is not limited to this, and the fiber may have further protrusions F1 and recesses F2, for example, a quadruple-leaf shape in which four protrusions F1 and four recesses F2 are alternately arranged, or a pentapleaf shape in which five protrusions F1 and five recesses F2 are alternately arranged.

[0027] [c Weight] The basis weight of the base paper sheet is 50 to 100 g / m2 from the viewpoint of achieving both the dirt retention ability and the flexibility of the sheet. 2 It is preferable that the basis weight is the basis weight measured in accordance with JIS P8124:2011 (hereinafter the same).

[0028] [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 of nano size (1 nm to 1000 nm), but the average fiber width is preferably 100 nm or less. The average fiber width can be calculated, for example, by using a certain number of number averages, medians, mode diameters (mode values), etc.

[0029] The CNF may be uniformly impregnated in the thickness direction of the base-paper sheet, but it is preferable that the CNF content gradually increases from the center in the thickness direction of the base-paper sheet toward the front and back surfaces, because this makes the cleaning wet sheet 100 less likely to tear even if the cleaning surface is strongly rubbed.

[0030] [(a) Pulp fibers that can be used for CNF] Pulp fibers that can be used to manufacture CNF include chemical pulps such as hardwood pulp (LBKP) and softwood pulp (NBKP); mechanical pulps such as bleached thermomechanical pulp (BTMP), stone ground pulp (SGP), pressed stone ground pulp (PGW), refiner ground pulp (RGP), chemi-ground pulp (CGP), thermo-ground pulp (TGP), ground pulp (GP), thermomechanical pulp (TMP), chemi-thermomechanical pulp (CTMP), and refiner mechanical pulp (RMP); waste paper pulp produced from brown paper, kraft envelope paper, magazine paper, newspaper paper, flyer paper, office paper, cardboard paper, white waste paper, Kent waste paper, imitation waste paper, land certificate waste paper, and recycled paper; and deinked pulp (DIP) produced by deinking waste paper pulp. These may be used alone or in combination as long as the effects of the present invention are not impaired.

[0031] [(b) CNF defibration method] Examples of defibration methods used in the production of CNF include mechanical methods such as the high-pressure homogenizer method, the microfluidizer method, the grinder grinding method, the bead mill freeze-grinding method, and the ultrasonic defibration method, but are not limited to these methods. In addition, CNF that has only been mechanically treated (not modified) using the above-mentioned defibration methods, i.e., CNF that has not been modified with functional groups, has higher thermal stability than CNF modified with functional groups such as phosphate groups and carboxymethyl groups, and can be used for a wider range of applications. However, CNF modified with functional groups such as phosphate groups and carboxymethyl groups can also be used in the present invention. In addition, for example, pulp fibers that have been mechanically defibrated may be subjected to chemical treatment such as carboxymethylation or enzyme treatment. Examples of CNF that have been chemically treated include iCNF (individualized CNF) (single nanocellulose) with a diameter of 3 nm to 4 nm, such as TEMPO-oxidized CNF, phosphate-esterified CNF, and phosphite-esterified CNF. In addition, CNF that has been subjected to only chemical or enzymatic treatment, or CNF that has been subjected to chemical or enzymatic treatment and then mechanical fiberization treatment may be used.

[0032] [(3) Chemical solution] The chemical solution to be impregnated into the base paper sheet as described above is weakly alkaline with a hydrogen ion exponent (pH) of 8.0 to 9.0, and contains 0.01 mass% to 0.25 mass%, preferably 0.10 mass% to 0.25 mass%, polyoxyethylene alkyl ether (AE), 1.00 mass% to 5.00 mass%, preferably 2.50 mass% to 5.00 mass%, ethanol, and 1.00 mass% to 5.00 mass%, preferably 3.00 mass% to 5.00 mass%, diethylene glycol monobutyl ether (DGME).

[0033] 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 dry mass of the base-paper sheet. The chemical solution is impregnated into the dried base paper sheet, and is released from the cleaning surface when the wet cleaning sheet 100 is used.

[0034] [(4) Embossing] As shown in Figures 1 and 2, the cleaning wet sheet 100 has embossments 20, which are areas where the sheet is compressed in the Z direction, to create unevenness in the sheet and scrape off dirt using the unevenness, thereby improving the wiping performance of dirt on the surface to be cleaned. The embossment 20 is formed in a so-called gourd shape, which is an elongated ellipse that is short in one direction and narrow in width in a plan view and has a constricted portion at approximately the center in the long axis direction, as shown in Fig. 2. The shape of the embossment 20 is not limited to this, and may be various shapes such as a polygon or a combination of various shapes, but from the viewpoint of improving the ability to scrape off dirt, such a gourd shape is preferable.

[0035] The embossments 20 can be formed by thermal embossing under conditions of a temperature of 80° C. to 200° C. and an embossing pressure of 0.2 MPa to 1.0 MPa. When the embossments 20 are formed by thermal embossing, the convex embossing roll may have at least an outer circumferential surface made of carbon steel, stainless steel, polypropylene, or a hardened resin such as ABS (Acrylonitrile Butadiene Styrene) resin, among which it is preferable to use one made of stainless steel from the viewpoints of durability and heat resistance. Furthermore, when embossing is performed by thermal embossing, it is preferable to perform this before the step of impregnating the wet cleaning sheet 100 with a chemical solution, from the viewpoint of facilitating the imparting of a concave-convex shape.

[0036] [a Convex embossing, concave embossing] The embossments 20 are formed as convex embossments 21 that are convex on the upper side in the Z direction (the first surface side of the wet cleaning sheet 100) and concave embossments 22 that are convex on the lower side (the second surface side of the wet cleaning sheet 100) (i.e., concave on the upper side in the Z direction). In each drawing, the convex embossments 21 are indicated by solid lines and the concave embossments 22 are indicated by dashed lines.

[0037] The convex embossment 21 is formed to have a size of 5 mm to 10 mm, preferably 6 mm to 8 mm in the long axis direction, 2 mm to 5 mm, preferably 3 mm to 4 mm in the short axis direction perpendicular to the long axis direction, and 0.5 mm to 2 mm, preferably 0.7 mm to 1.5 mm in the Z direction (height from an intermediate portion (described later)). The concave embossment 22 is formed upside down and in substantially the same shape as the convex embossment 21 in cross-sectional view, and is formed to have a shape that is convex downward in the Z direction.

[0038] [b middle part] An intermediate portion is formed between each of the embossments 20 formed on the cleaning wet sheet 100. Since the intermediate portion is a portion where no embossment 20 is formed, the intermediate portion is located lower than the convex embossment 21 and higher than the concave embossment 22 in the Z direction.

[0039] [c Embossed Pattern] In the wet cleaning sheet 100 according to the present embodiment, as shown in FIG. 2, for example, a diamond-shaped first embossed block 30 is formed by a combination of convex embossments 21 and concave embossments 22 such that an angle between a first direction (X direction in FIG. 2) perpendicular to a first side a and the long axis direction is 5° to 45°, preferably 15° to 35°. The first embossed block 30 is continuous from the first side a to the second side b to form an embossed block row 31, and the embossed block row 31 is continuous from the third side c to the fourth side d. In a plurality of adjacent first embossing block rows 31 and second embossing block rows 31, a first embossing block 30 in the first embossing block row 31 overlaps with an adjacent second embossing block 30 in the second embossing block row 31 in a second direction (Y direction in Figure 2) perpendicular to the first direction, and at least one convex embossing 21 and one concave embossing 22 are located on a straight line extending from any point on the third side c perpendicular to the fourth side d.

[0040] [d Non-embossed part] As shown in FIG. 2, between adjacent embossed blocks 30, there are provided non-embossed portions 40, which are portions of the cleaning wet sheet 100 that are not compressed in the Z direction compared to the portions where the embossments 20 are formed and have raised nap.

[0041] The non-embossed portion 40 can be formed by designing the convex embossing roll that forms the embossment 20 so as to eliminate the shape of the non-embossed portion 40, or by compressing it lightly compared to the compressed portion of the embossment 20 so that the nap remains. By providing such non-embossed portions 40 at 25% to 50% of the area of ​​the wet cleaning sheet 100, the occurrence of wiping streaks can be reduced, resulting in a wet cleaning sheet 100 with excellent wiping ability. It is most preferable that the non-embossed portions 40 be provided at 25% of the area of ​​the wet cleaning sheet 100.

[0042] When the wet cleaning sheet 100 is attached to the cleaning tool 200 and used for wiping, it is usually moved approximately perpendicular to the X or Y direction, but if the non-embossed portion 40 is formed in a straight line as shown in Fig. 2, wiping streaks may easily occur depending on the angle at which the wet cleaning sheet 100 is moved. Therefore, it is more desirable to arrange the embossed block 30 so that the non-embossed portion 40 is not in a straight line.

[0043] [2. Description of Effects] First, according to the cleaning wet sheet 100 of this embodiment, the hydrophobic fibers contained in the base-paper sheet include irregular cross-section fibers F, the cross-section of which has a shape in which a plurality of convex portions F1 and a plurality of concave portions F2 are alternately arranged, as shown in FIG. As a result, dirt on the surface to be cleaned can be scraped off by the convex portions F1 and concave portions F2, thereby improving the wiping performance against dirt compared to conventional wet cleaning sheets in which the base paper sheet is formed only from fibers with a circular cross-section.

[0044] Furthermore, according to the cleaning wet sheet 100 of this embodiment, the chemical solution used to impregnate the base-paper sheet is weakly alkaline with a hydrogen ion exponent (pH) of 8.0 to 9.0, and contains 0.01 mass % to 0.25 mass % polyoxyethylene alkyl ether (AE), 1.00 mass % to 5.00 mass % ethanol, and 1.00 mass % to 5.00 mass % diethylene glycol monobutyl ether (DGME). When the surface to be cleaned is a waxed or coated surface such as a floor, the chemical solution contained in the cleaning wet sheet may cause discoloration or peeling of the wax or coating, and this risk is particularly high when a chemical solution with high cleaning power is used to improve wiping performance. However, in this embodiment, by using the above-mentioned chemical solution, drying is relatively quick and the pH is 9 or less, the speed of deterioration of the surface to be cleaned is suppressed, thereby further improving the wiping performance against dirt while reducing the possibility of damaging the surface to be cleaned, such as a floor.

[0045] In addition, according to the cleaning wet sheet 100 of this embodiment, by arranging the embossments 20 as described above, the unevenness of the sheet can further improve the wiping performance against dirt, and the following effects can be obtained.

[0046] That is, normally, when the cleaning wet sheet 100 is attached to the cleaning tool 200 having the head unit 201 and used to wipe, it is moved in a first direction (X direction in FIG. 2) or a second direction (Y direction in FIG. 2). However, if the convex embossments are arranged in series so as to align along such a first or second direction, there may be areas on the surface to be cleaned that have not been wiped by the convex embossments (so-called "wiping streaks"). When a user sees the wiping streaks, he or she may determine that the chemical solution has run out and the sheet has dried out, even though there is still chemical solution remaining in the sheet, and discard the sheet, which may result in the use of many sheets unnecessarily.

[0047] In contrast, when a cleaning wet sheet 100 is attached having the above-mentioned embossing pattern and in which at least one convex embossment 21 is arranged on a straight line extending perpendicularly from any point on the third side c to the fourth side d, when wiping is performed at least in the second direction (the Y direction in Figure 2), the convex embossments 21 will have an overlapping margin, thereby reducing the occurrence of wiping streaks.

[0048] Furthermore, by not providing embossments 20 over the entire surface of the cleaning wet sheet 100, but providing non-embossed sections 40 between each embossed block 30, covering 25% to 50% of the area of ​​the cleaning wet sheet 100, when wiping with the cleaning wet sheet 100, the convex embossments 21 that protrude beyond the non-embossed sections 40 are subjected to greater pressure, improving the release of chemicals and further reducing the occurrence of wiping streaks. Furthermore, by receiving a larger pressure on the convex embossments 21, the scraping ability of the convex embossments 21 is improved, and dirt is more likely to accumulate in the non-embossed portions 40, thereby improving the dirt collection ability. Even if the scraping ability of the convex embossments 21 and the dirt collection ability of the cleaning wet sheet 100 are improved, the convex embossments 21 make it more difficult for the non-embossed portions 40 to come into contact with the surface to be cleaned, thereby suppressing an increase in wiping resistance.

[0049] Furthermore, since the embossed block 30 is rhombus-shaped and made of the embossments 20 whose angle with respect to the first direction is 5° to 45°, preferably 15° to 35°, when a plurality of embossed block rows 31, each row being arranged continuously from the first side a to the second side b, are arranged continuously from the third side c to the fourth side d, the embossed blocks 30 are inevitably arranged so as to be misaligned with respect to the first direction of the wet cleaning sheet 100. Also, this allows more leeway in the angle at which the wet cleaning sheet 100 can be moved when the user is wiping.

[0050] Furthermore, the embossment 20 has an elliptical shape with a constricted portion approximately in the center in the long axis direction, so that the dirt scraping performance can be improved.

[0051] [3 Variations] Below, a modification of the above embodiment will be described.

[0052] [(1) Adoption of multi-layered sheets] In the above, a single-layer nonwoven fabric formed by mixing hydrophilic fibers and hydrophobic fibers is used as the base-paper sheet. However, instead of this, a multi-layered sheet having a hydrophilic fiber layer mainly made of hydrophilic fibers and a hydrophobic fiber layer mainly made of hydrophobic fibers may be used.

[0053] Specifically, for example, a three-layer structure may be formed in which the surface layers on both sides are hydrophobic fiber layers mainly made of hydrophobic fibers and the middle layer is a hydrophilic fiber layer mainly made of hydrophilic fibers, and the fibers of the hydrophobic fiber layer and the hydrophilic fiber layer are configured so that they are entangled with each other at the boundary region between the fibers of the hydrophobic fiber layer and the fibers of the hydrophilic fiber layer. In order to improve the dirt wiping performance of the cleaning wet sheet, it is necessary that the modified cross-section fibers are included so as to be exposed on the surface of the base-paper sheet. In this case, the modified cross-section fibers are included as hydrophobic fibers constituting the hydrophobic fiber layer.

[0054] In this case, the chemical solution impregnated into the hydrophilic fiber layer is less likely to be released onto the surface to be cleaned adjacent to the hydrophobic fiber layer, and the chemical solution can be selectively released onto the surface to be cleaned, thereby suppressing the release of the chemical solution that is not effective for cleaning. Furthermore, 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 drug solution.

[0055] [(2) Use of fibers with multiple cross-section shapes] In the above, a case has been described in which the hydrophobic fiber contained in the base-paper sheet is one type of fiber having a cross-sectional shape in which three convex portions F1 and three concave portions F2 are alternately arranged as shown in FIG. 3, but a mixture of fibers having multiple types of irregular cross-sections may also be used. For example, the base paper sheet includes both a modified cross-section fiber having a cross-sectional shape in which three convex portions F1 and three concave portions F2 are alternately arranged as shown in FIG. 3, and a modified cross-section fiber having a cross-sectional shape in which a larger number of convex portions F1 and concave portions F2 are alternately arranged.

[0056] In this case, by including a plurality of types of modified cross-section fibers which are suitable for wiping different types of dirt, it is possible to effectively improve wiping performance against a greater number of types of dirt.

[0057] [(3) Changing the embossing pattern] In the above, the case where the embossed block 30 consisting of a combination of the convex embossments 21 and the concave embossments 22 is formed on the wet cleaning sheet 100 has been exemplified, but it is sufficient that the embossed block 30 has at least the convex embossments 21. However, providing the concave embossments 22 is preferable because it allows the cleaning wet sheet 100 to be turned over for use, thereby making it possible to increase the cleaning area.

[0058] In addition, in Figures 1 and 2, a diamond-shaped embossed block 30 is shown as an example, which is made of an embossment 20 in which the angle between the first direction and the long axis direction is 5° to 45°, and preferably 15° to 35°. However, the shape of the embossed block 30 is not limited to this, and the embossed block 30 may be, for example, an embossed block 30 made of an embossment 20 in which the angle between the first direction and the long axis direction is 0° or 90°.

[0059] In addition, in Figures 1 and 2, the convex embossings 21 and the concave embossings 22 in each embossing block 30 are illustrated as having the same angle between the long axis direction and the first direction, but this is not limited to this, and as shown in Figure 4, the convex embossings 21 and the concave embossings 22 in the first embossing block 30 may be arranged so that the orientation of the long axis direction is different from the orientation of the long axis direction of the convex embossings 21 and the concave embossings 22 in the second embossing block 30 adjacent to the first embossing block 30. Moreover, the convex embossments 21 and the concave embossments 22 in the first embossing block 30 may be arranged so that their angles differ from each other.

[0060] In addition, 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, but this is not limited to this.

[0061] In addition, in each of the drawings, the convex embossment 21 and the concave embossment 22 are both substantially the same gourd shape in plan view, but the convex embossment 21 and the concave embossment 22 may have different shapes.

[0062] However, in any of the above embossing patterns, it is preferable that the convex embossments 21 and the concave embossments 22 are arranged substantially symmetrically on the first and second sides of the wet cleaning sheet 100. In this way, the first and second sides of the wet cleaning sheet 100 have the same level of cleaning function, and the cleaning area per sheet can be increased.

[0063] (4) Use of hydrophilic fibers with irregular cross sections In the above, the hydrophobicity contained in the base paper sheet sex Although the case where the modified cross-section fiber is used as the fiber has been described, the modified cross-section fiber is not limited to this as long as it is arranged so as to be exposed on the surface of the base paper sheet. For example, a modified cross-section hydrophilic fiber may be used, or both a modified cross-section hydrophilic fiber and a modified cross-section hydrophobic fiber may be used. However, in order to efficiently improve the wiping performance against dirt, it is preferable to use hydrophobic fibers having a modified cross section. EXAMPLES

[0064] Next, the results of evaluation of the examples of the present invention and the comparative examples will be described. The present invention will be specifically described below with reference to the examples, but the present invention is not limited to these.

[0065] [1 Comparison of fiber composition of base paper sheets] First, the results of evaluating the difference in wiping performance against dirt depending on the composition of the fibers constituting the base-paper sheet will be described.

[0066] [(1) Sample Creation] The following wet cleaning sheets were prepared according to the following examples and comparative examples.

[0067] [a Example 1-1] As a base sheet, the basis weight is 100g / m 2A nonwoven fabric (rectangular with long sides of 300 mm and short sides of 200 mm) made of 90% by mass PET fiber and 10% by mass PP / PE binder and bonded using spunlace was used, and purified water, which acted as a chemical solution, was impregnated into the fabric in an amount of 400% by mass based on the dry mass of the base paper sheet. The PET fiber used was a fiber with a modified cross section, which when cut perpendicular to the longitudinal direction of the fiber, has a trefoil shape as shown in Figure 3; specifically, Toray Industries, Inc.'s "Trilobal PET" (1.4 dtex, fiber length 38 mm) was used. No embossing was applied.

[0068] [b Comparative example 1-1] As a base sheet, the basis weight is 100g / m 2 A nonwoven fabric (rectangular with long sides of 300 mm and short sides of 200 mm) made of 90% by mass PET fiber and 10% by mass PP / PE binder and bonded using spunlace was used, and purified water, which acted as a chemical solution, was impregnated into the fabric in an amount of 400% by mass based on the dry mass of the base paper sheet. The PET fiber used was a fiber that has a circular cross section when cut perpendicular to the longitudinal direction of the fiber, specifically, "Regular Hydrophilic PET" (1.4 dtex, fiber length 38 mm) manufactured by Toray Industries, Inc. No embossing was applied.

[0069] [(2) Test Content] The following stain removal test was carried out using the cleaning wet sheets according to the above examples and comparative examples.

[0070] [a Creation of artificial dirt] Ten simulated liquid stains were created in a row along the short side of a rectangular PP board with a long side of 400 mm and a short side of 180 mm in the center of the long side. Specifically, the stains were created in ten locations, 1.5 cm apart, from a position 1.5 cm away from one of the long sides to a position 15 cm away. As a simulated stain, Ezaki Glico Co., Ltd.'s "Mild Cafe au Lait" was used, and 0.3 ml was dropped onto each spot and then dried at 60°C for 1 hour.

[0071] [b. Wipe test] The wipe test was carried out in the following manner.

[0072] (i) The sheet of Example 1-1 or Comparative Example 1-1 is placed on the right end of the PP plate (one end of the long side of the PP plate, located on the right side as seen by the tester) with the long side of the sheet aligned along the short side of the PP plate. (ii) Place the head of the cleaning tool (rectangular with a long side of 250 mm and a short side of 100 mm) on the sheet so that the long side of the head is aligned with the short side of the PP board, and then place a weight on top of the head. The total weight of the head of the cleaning tool and the weight is 2000 g. (iii) The weight is pushed horizontally, and together with the sheet and head, it is moved 200 mm toward the left end of the PP plate (the other end opposite the above-mentioned end in the long side direction of the PP plate, which is located on the left side as seen by the tester). The time required for the movement is 4 seconds. (iv) The weight is pushed horizontally and moved 200 mm toward the right end of the PP board together with the sheet and head. The time required for the movement is 4 seconds.

[0073] The above steps (iii) and (iv) were repeated five times, and the state of the artificial dirt on the PP plate was checked after each step. Hereinafter, each step of steps (iii) and (iv) is referred to as one wiping.

[0074] [(3) Test results] The test results are shown in Table I. The test results were evaluated visually based on the number of artificial stains wiped off after three wiping cycles and after five wiping cycles, as follows:

[0075] In other words, for each of the 10 artificial stains, the number of remaining artificial stains was counted as 1 if more than half the area before the test was remaining, 0.5 if less than half the area before the test was remaining, and 0 if it was no longer visible to the naked eye. This was then subtracted from the initial number (10) to calculate the number of artificial stains wiped off.

[0076] [Table 1]

[0077] (4) Evaluation Comparing the results of the wiping test for Example 1-1, in which irregular cross-section fiber was used as the PET fiber, with the results of the wiping test for Comparative Example 1-1, in which fiber with a circular cross-section was used as the PET fiber, Example 1-1 showed a greater number of artificial stains wiped off both after three wipes and after five wipes. From this point of view, it can be seen that by using modified cross-section fibers with a cross-sectional shape as shown in Figure 3 for the base paper sheet of the wet cleaning sheet, the wiping performance of the wet cleaning sheet against dirt can be improved.

[0078] [2. Comparison of chemical solution composition] Next, the results of an evaluation of the difference in the wiping performance against dirt and the effect on the surface to be cleaned (floor surface) depending on the composition of the chemical solution impregnated into the base-paper sheet will be described.

[0079] [(1) Sample Creation] The following wet cleaning sheets were prepared according to the following examples and comparative examples.

[0080] [a Example 2-1] Base sheet weight: 60g / m 2 The nonwoven fabric (rectangular shape with long sides of 300 mm and short sides of 200 mm) was made of 40% by mass of PET fiber, 40% by mass of rayon fiber, and 20% by mass of PP / PE binder, and was bonded by spunlace. It was not embossed. The chemical solution used to impregnate the base paper sheet contained 2.50 mass% ethanol, 1.50 mass% diethylene glycol monobutyl ether (DGME), and 0.05 mass% polyoxyethylene alkyl ether (AE) (the remaining components were purified water), and had a pH of 8.8. The base paper sheet was impregnated with 300 mass% of the dry mass of the base paper sheet.

[0081] [b Example 2-2] The chemical solution used to impregnate the base paper sheet contained 2.50% by mass of ethanol, 3.00% by mass of DGME, and 0.10% by mass of AE (the remaining components were purified water) and had a pH of 8.6. The other points were the same as in Example 2-1.

[0082] [c Example 2-3] The chemical solution used to impregnate the base paper sheet contained 5.00% by mass of ethanol, 5.00% by mass of DGME, and 0.25% by mass of AE (the remaining components were purified water) and had a pH of 9.0. The other points were the same as in Example 2-1.

[0083] [d Examples 2-4] The chemical solution used to impregnate the base paper sheet contained 1.00% by mass of ethanol, 1.00% by mass of DGME, and 0.01% by mass of AE (the remaining components were purified water), and had a pH of 8.0. The other points were the same as in Example 2-1.

[0084] [e Comparative Example 2-1] The chemical solution used for impregnating the base paper sheet did not contain ethanol, DGME, or AE, and had a pH of 7.2 (purified water). The other points were the same as in Example 2-1.

[0085] [f Comparative Example 2-2] The chemical solution used to impregnate the base paper sheet contained 0.50% by mass of ethanol, 0.50% by mass of DGME, and 0.00% by mass of AE (the remaining components were purified water) and had a pH of 10.0. The other points were the same as in Example 2-1.

[0086] [g Comparative Example 2-3] The chemical solution used to impregnate the base paper sheet contained 7.00% by mass of ethanol, 1.00% by mass of DGME, and 0.01% by mass of AE (the remaining components were purified water) and had a pH of 8.3. The other points were the same as in Example 2-1.

[0087] [h Comparative Example 2-4] The chemical solution used to impregnate the base paper sheet contained 2.50% by mass of ethanol, 10.00% by mass of DGME, and 0.01% by mass of AE (the remaining components were purified water) and had a pH of 8.7. The other points were the same as in Example 2-1.

[0088] [(2) Test Content] The following stain removal test was carried out using the cleaning wet sheets according to the above examples and comparative examples.

[0089] [a Creation of artificial dirt] The following two types of artificial soil were created:

[0090] [(a) Artificial dirt 1: Crayon] A crayon stain was applied to the centre (the central part in both the long and short sides) of a rectangular PP board with a long side of 300 mm and a short side of 180 mm to simulate sebum stains. Specifically, a 30 mm square was drawn using oil crayons (approximately 75%) and pigment (approximately 25%) manufactured by Daiso Industries Co., Ltd., and then dried at room temperature for 2 minutes.

[0091] [(b) Artificial stain 2: Cafe au lait] A cafe au lait stain was applied to the centre (the central part in both the long and short directions) of a rectangular PP board with a long side of 300 mm and a short side of 180 mm, to simulate liquid stains. Specifically, 0.5 ml of "Mild Cafe au Lait" manufactured by Ezaki Glico Co., Ltd. was dropped onto the sample, followed by drying at 60°C for 1 hour.

[0092] [b. Wipe test] The wipe test was carried out in the following manner.

[0093] (i) A sheet of an example or comparative example is placed on the right end of the PP plate (one end of the long side of the PP plate, located on the right side as seen by the tester) with the long side of the sheet aligned along the short side of the PP plate. (ii) Place the head of the cleaning tool (rectangular with a long side of 250 mm and a short side of 100 mm) on the sheet so that the long side of the head is aligned with the short side of the PP board, and then place a weight on top of the head. The total weight of the head of the cleaning tool and the weight is 300 g. (iii) The weight is pushed horizontally, and together with the sheet and head, it is moved 200 mm toward the left end of the PP plate (the other end opposite the above-mentioned end in the long side direction of the PP plate, which is located on the left side as seen by the tester). The time required for the movement is 4 seconds. (iv) The weight is pushed horizontally and moved 200 mm toward the right end of the PP board together with the sheet and head. The time required for the movement is 4 seconds.

[0094] The above steps (iii) and (iv) were repeated 30 times, and the state of the artificial dirt on the PP plate was checked every 3 times. Hereinafter, each step of steps (iii) and (iv) is referred to as one wiping.

[0095] [c. Testing the impact on floor surfaces] Tests on the impact on floor surfaces were conducted using the following method.

[0096] (i) Prepare flooring (composite flooring, Home Floor manufactured by DIY Century Co., Ltd., product number: HF-100N) and cut it into 5 cm squares. Then measure the color of the flooring using a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd.; product number NF333_simple spectrophotometer). (ii) The floor material is wrapped in a cleaning wet sheet of the Example or Comparative Example, placed in a sealed bag, and left at room temperature for 18 hours. (iii) After leaving it for 18 hours, remove the flooring from the sealed bag and dry it in a 40℃ thermostatic chamber for one day. Then measure the color of the dried flooring with the same color difference meter as in (i) and measure the color difference ΔE from the original color. Note that the larger the ΔE value, the greater the degree of discoloration.

[0097] [(3) Test results] The results of the tests are shown in Table II.

[0098] The removal of dirt in the wiping test was evaluated as follows. That is, for crayon (pseudo soil 1), the number of times it was wiped off until the soiling was removed (the soiling was no longer visible to the naked eye) was indicated as ◎ if it took 10 or fewer wipes, ◯ if it took more than 11 but no more than 20 wipes, △ if it took more than 21 but no more than 30 wipes, and × if it took 31 or more wipes (the soiling was not removed after 30 wipes). In addition, for cafe au lait (pseudo stain 2), if it took 5 or fewer wipes to remove the stain, it was marked with an ◎, if it took more than 6 but no more than 10 wipes, it was marked with an ◯, if it took 11 or more but no more than 15 wipes, it was marked with a △, and if it took 16 or more wipes, it was marked with an ×.

[0099] The impact on the floor was evaluated as follows: In other words, when ΔE was 2.5 or more, it was determined that discoloration had occurred in the flooring material, and when there were three or more blister-like floating areas of Φ1 mm or more on a 5 cm square area of ​​flooring material, it was determined that peeling had occurred in the flooring material.

[0100] [Table 2]

[0101] (4) Evaluation A comparison of Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-4 reveals that by using a chemical solution with a hydrogen ion exponent (pH) of 8.0 to 9.0 containing 0.01% by mass to 0.25% by mass of polyoxyethylene alkyl ether (AE), 1.00% by mass to 5.00% by mass of ethanol, and 1.00% by mass to 5.00% by mass of diethylene glycol monobutyl ether (DGME) as the chemical solution to be impregnated into the base paper sheet, it is possible to improve the wiping performance for dirt on the surface to be cleaned without increasing the risk of discoloration, peeling, and other effects on the floor surface.

[0102] That is, in all of Examples 2-1 to 2-4, which have a hydrogen ion exponent (pH) of 8.0 to 9.0 and contain 0.01% to 0.25% by mass of polyoxyethylene alkyl ether (AE), 1.00% to 5.00% by mass of ethanol, and 1.00% to 5.00% by mass of diethylene glycol monobutyl ether (DGME), the stain removal performance for both crayon and cafe au lait was rated as ◎ or ◯, and no discoloration or peeling occurred on the floor surface.

[0103] In contrast to this, first, in Comparative Example 2-1, which does not contain any of polyoxyethylene alkyl ether, ethanol, and diethylene glycol monobutyl ether, the stain removal was rated as △ for crayon and × for cafe au lait. In addition, for Comparative Example 2-2, which does not contain polyoxyethylene alkyl ether and contains ethanol and 0.50 mass % diethylene glycol monobutyl ether, the stain removal was rated fair for both crayon and cafe au lait. In addition, in Comparative Example 2-2 with a pH of 10.0, Comparative Example 2-3 containing 7.00 mass % of ethanol, and Comparative Example 2-4 containing 10.00 mass % of diethylene glycol monobutyl ether, discoloration and peeling occurred on the floor surface.

[0104] [Comparison of 3 embossing configurations] Next, the results of evaluation of the effect of the embossing pattern formed on the wet cleaning sheet on the amount of wiping streaks, the amount of wiping removed, and the wiping resistance will be described.

[0105] [(1) Sample Creation] The following test sheets were prepared for the examples and comparative examples.

[0106] [a Example 3-1: Non-embossed portion 25%] Weight 40g / m 2 ~50g / m 2The two hydrophobic fiber layers are made of 80% PET and 20% PP / PE binder by weight, and the fabric weight is 40 g / m 2 ~50g / m 2 A hydrophilic fiber layer consisting of 70% by mass of pulp and 30% by mass of PPSB was prepared, and then entangled by a water flow entanglement method so that both sides of the hydrophilic fiber layer were sandwiched between the hydrophobic fiber layers. The resulting base paper sheet was then cut to a size of 300 mm x 200 mm, and subjected to thermal embossing processing as described below under conditions of a temperature of 95°C and an embossing pressure of 0.4 MPa.

[0107] That is, as shown in FIG. 2, a plurality of diamond-shaped first embossed blocks 30 each consisting of a combination of a gourd-shaped convex embossment 21 and a concave embossment 22, each of which has an angle of 30° between the first direction (the X-direction in FIG. 2) and the long axis direction, are arranged in succession from a first side a to a second side b opposite the first side a, and a plurality of embossed block rows 31 are arranged in succession from a third side c to a fourth side d. In this case, in adjacent first embossed block rows 31 and second embossed block rows 31, the first embossed block 30 in the first embossed block row 31 overlaps with the adjacent second embossed block 30 in the second embossed block row 31 in the first direction, and the embossments 20 are arranged so that at least one convex embossment 21 is present on a line extending perpendicularly from an arbitrary point on the third side c to the fourth side d, and non-embossed portions 40 are provided between each embossed block 30 so as to cover 25.0% of the area of ​​the base paper sheet.

[0108] In addition, the base paper sheet after the thermal embossing process was impregnated with a chemical solution containing an aqueous detergent, an antiseptic, a disinfectant, and alcohol in an amount of 300% by mass based on the dry mass of the base paper sheet.

[0109] [b Example 3-2: Non-embossed portion 37.5%)] As shown in FIG. 5A, the non-embossed portion 40 was provided so as to cover 37.5% of the area of ​​the base-paper sheet. The other points are the same as in Example 3-1.

[0110] [c Example 3-3: Non-embossed portion 50%)] As shown in FIG. 5B, the non-embossed portion 40 was provided so as to cover 50.0% of the area of ​​the base-paper sheet. The other points are the same as in Example 3-1.

[0111] [d Comparative Example 3-1: Non-embossed portion 0%, arranged in series] As shown in Fig. 5C, gourd-shaped convex embossments and concave embossments whose long axis directions are parallel to the first direction were arranged alternately over the entire surface of the base paper sheet to create a test sheet that did not have a non-embossed portion 40. The other points were the same as those of Example 3-1.

[0112] [e Comparative Example 3-2: Non-embossed portion 0%, zigzag shape] The gourd-shaped embossing has a plurality of first convex embossments and second convex embossments whose orientations in the long axis direction are different from each other, and the first convex embossments adjacent to each other in the short axis direction are arranged so that portions of both first convex embossments overlap in the short axis direction and are shifted in the long axis direction, and the second convex embossings adjacent to each other in the short axis direction are arranged so that portions of both second convex embossments overlap in the short axis direction and are shifted in the long axis direction. Such a plurality of first convex embossments and second convex embossments were adjacent to each other so that their major axis directions were at approximately right angles to each other, and were continuously arranged from a first side a of the base paper sheet toward a second side b opposite to the first side a. In addition, concave embossments were arranged in the same embossing 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. 5D was prepared. The other points are the same as in Example 3-1.

[0113] [f Comparative Example 3-3: Non-embossed area 100%] A test sheet was prepared without embossing, having only a non-embossed portion 40. The other points were the same as in Example 3-1.

[0114] [(2) Test Content] The cleaning wet sheets of Examples 3-1 to 3-3 and Comparative Examples 3-1 to 3-3 were each attached to a cleaning tool having a rectangular flat head portion of 250 mm x 100 mm to prepare wipers with cleaning wet sheets of Examples 3-1 to 3-3 and Comparative Examples 3-1 to 3-3. The following Tests 1 to 3 were performed using the wipers with cleaning wet sheets.

[0115] [a Test 1: Wipe streak test] (i) A wet wiper with a weight of 400g in total was placed on the right edge of the blackboard (the edge of the long side of the blackboard located on the right side as seen by the tester) so that the head of the wiper faces directly. The blackboard used was a wooden wall-mounted blackboard (450mm x 300mm in size) manufactured by Umajirushi Co., Ltd. (ii) Push the weight and the wiper with wet sheet from the right end of the blackboard to the left end (the other end opposite the above-mentioned end along the long side of the blackboard, located on the left side as seen by the tester) and move it 300 mm. (iii) The resulting wiping streaks were visually evaluated as follows: ◯: almost no wiping streaks on the cleaning surface (wet area was about 90% to 100% of the entire cleaning surface), △: slight wiping streaks (wet area was about 80% to 90% of the entire cleaning surface), and ×: many wiping streaks (wet area was 80% or less of the entire cleaning surface).

[0116] [b Test 2: Wipeability test] (i) 15 ml of simulated soil made from a mixture of beef tallow, olive oil, chloroform and fluorescent paint in a ratio of 12.5:12.5:74.4:0.6 (mass ratio) is dropped and spread onto a 480 mm x 320 mm stainless steel plate, and then the plate is dried for 5 minutes in a hot air dryer (temperature 60°C) and the weight of the stainless steel plate is measured. (ii) Place a wet sheet wiper with weights added so that the total weight is 500 g on the right end of the stainless steel plate (one end of the long side of the stainless steel plate that is located on the right side as seen by the tester) so that the head part faces directly. (iii) Push and move the weight and the wet sheet wiper from the right end of the stainless steel plate to the left end (the other end opposite the above-mentioned end in the long side direction of the stainless steel plate, located on the left side as seen by the tester), and dry only the stainless steel plate again in a hot air dryer (temperature 60°C) for 5 minutes and measure the weight. (iv) The wiping amount of each cleaning wet sheet is calculated 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) Steps (i) to (iv) are repeated twice, and the average amount of wiped off is calculated.

[0117] [c Test 3: Wipe resistance test] (i) A wiper with a wet sheet attached, weighted to a total weight of 500 g, was placed on the composite flooring with the head facing directly. The composite flooring used was DIY Century Home Floor (product number: HF-100N). (ii) A hole is drilled in the head connection part of the wiper body, and a push-pull gauge (DS2-200N manufactured by Imada Co., Ltd.) is attached to the hole. (iii) Measure the maximum resistance when the wet sheet wiper equipped with a push-pull gauge is pulled 50 cm. (iv) (iii) above is repeated five times and the average wiping resistance is calculated.

[0118] [(3) Test results] The results of Tests 1 to 3 are shown in Table III.

[0119] [Table 3]

[0120] (4) Evaluation Comparing the results of Test 1, it can be seen that the occurrence of wiping streaks is reduced in Examples 3-1 to 3-3, which are provided with the non-embossed portion 40, compared to Comparative Example 3-1 and Comparative Example 3-2, which are not provided with the non-embossed portion 40. This is thought to be because the pressure applied to the convex embossments 21 is increased by the amount of the non-embossed portion 40, improving the release of the chemical solution. On the other hand, when comparing Examples 3-1 to 3-3 and Comparative Example 3-3, the occurrence of wiping streaks increased, albeit slightly, as the ratio of the non-embossed portion 40 was increased. This is thought to be because as the ratio of the non-embossed portion 40 is increased, the number of protruding embossments 21 decreases accordingly, reducing the contact area with the blackboard and decreasing the release of the chemical solution.

[0121] Furthermore, when comparing the results of Test 2, it can be seen that the wiping performance is improved since the wiping amount is greater in Examples 3-1 to 3-3, which have a non-embossed portion 40, than in Comparative Examples 3-1 and 3-2, which did not have a non-embossed portion 40. On the other hand, when comparing Example 3-1 to Example 3-3, it is found that Example 3-1, which has 25% non-embossed portion 40, is able to wipe off the most dirt, and the amount of dirt wiped off decreases as the non-embossed portion 40 increases. This is thought to be because, as described above, as the ratio of the non-embossed portion 40 increases, the number of convex embossments 21 decreases accordingly, decreasing the release of the chemical solution and the ability to scrape off dirt.

[0122] Furthermore, when comparing the results of Test 3, only Comparative Example 3-3, which did not have an embossing 20 on the entire surface, had a stronger wiping resistance, but there was no significant difference in wiping resistance between Comparative Examples 3-1 and 3-2, which did not have a non-embossed portion 40, and Examples 3-1 to 3-3, which had a non-embossed portion 40. This is believed to be because the non-embossed portion 40 is less likely to come into contact with the surface to be cleaned, and therefore the wiping resistance of the entire wet cleaning sheet 100 does not change significantly. [Explanation of symbols]

[0123] 100 Cleaning Wet Sheets 20 Embossing 21 Convex embossing 22 Concave embossing 30 Embossed Block 31 Embossed Block Row 40 Non-embossed section 200 Cleaning equipment 201 Head a First side b Second side c Third side d Fourth side F: irregular cross-section fiber F1 Convex F2 recess

Claims

1. A wet cleaning sheet in which a base paper sheet is impregnated with a chemical solution, The base paper sheet includes modified cross-section fibers having a cross-section in which a plurality of convex portions and a plurality of concave portions are alternately arranged, The cleaning wet sheet is characterized in that the chemical solution has a hydrogen ion exponent of 8.0 to 9.0, and contains 0.01% by mass to 0.25% by mass of polyoxyethylene alkyl ether, 1.00% by mass to 5.00% by mass of ethanol, and 1.00% by mass to 5.00% by mass of diethylene glycol monobutyl ether.

2. The base paper sheet includes hydrophilic fibers and hydrophobic fibers, The wet cleaning sheet according to claim 1, wherein the hydrophobic fibers include the modified cross-section fibers.

3. 3. The cleaning wet sheet according to claim 2, wherein the modified cross-section fiber is a polyethylene terephthalate fiber.

4. The first surface of the wet cleaning sheet is provided with an embossing block having a plurality of convex embossments, a plurality of the embossing blocks are arranged continuously from a first side to a second side opposite to the first side to form an embossing block row; a non-embossed portion where the embossing is not arranged between adjacent ones of the embossing blocks; the embossed block rows are arranged continuously from a third side perpendicular to the first side to a fourth side opposite to the third side, The non-embossed portion is provided so as to occupy 25% or more and 50% or less of the area of ​​the cleaning wet sheet, The cleaning wet sheet according to any one of claims 1 to 3, characterized in that at least one of the convex embossments is arranged on a straight line extending perpendicularly from an arbitrary point on the third side to the fourth side.

5. The second surface of the wet cleaning sheet is provided with a concave embossment, which is a convex embossment, The embossing block is composed of a combination of a plurality of the convex embossments and the concave embossments, The wet cleaning sheet according to claim 4, wherein at least one of the recessed embossments is disposed on a line extending from an arbitrary point on the third side to the fourth side.

6. an angle between a major axis direction of the embossment and a first direction perpendicular to the first side is 5° or more and 45° or less; 6. The wet cleaning sheet according to claim 4, wherein the embossed block is rhombus-shaped.

7. 7. The wet cleaning sheet according to claim 4, wherein the embossment is elliptical in shape and has a constricted portion at approximately the center in the major axis direction.

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