Cleaning sheet

Abstract

To provide a wet-type cleaning sheet capable of easily collecting dust of various sizes.SOLUTION: A cleaning sheet (1) is a wet-type cleaning sheet including a first sheet-like member (11), a second sheet-like member (12) overlapping the first sheet-like member, and a bonding part (31) bonding the first sheet-like member and the second sheet-like member, where at least one of the first sheet-like member and the second sheet-like member is impregnated with a chemical solution. In a wet-pressed state where the cleaning sheet is impregnated with 300% or more of the chemical solution relative to the weight of the cleaning sheet and pressed by a pressure of the 7.00 kPa-8.00 kPa, the thickness (T12) of the cleaning sheet in a non-bonded area (R12) where the bonding part (31) is not provided is 3.0 times or more the thickness of the cleaning sheet in the bonded area (R11) where the bonding part (31) is provided.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a cleaning sheet having a plurality of sheet-shaped members.

[0002] Patent Documents 1 and 2 disclose cleaning sheets having multiple sheet-like members. The cleaning sheet of Patent Document 1 has an inner layer sheet and an outer layer sheet as sheet-like members, and is attached to a cleaning tool having a plate-shaped opposing surface facing the surface to be cleaned. The cleaning sheet of Patent Document 2 has a first fiber layer and a second fiber layer as sheet-like members, and is attached to a cleaning tool or used as a standalone sheet without being attached to a cleaning tool. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-100950 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-234253 Summary of the Invention

[0004] A cleaning sheet attached to a cleaning tool is pressed against the surface to be cleaned via the cleaning tool during cleaning. At this time, the cleaning sheet is moved against the surface to be cleaned while receiving a predetermined pressure from both sides by the cleaning tool and the surface to be cleaned, and collects dust from the surface to be cleaned. Meanwhile, a cleaning sheet used without being attached to a cleaning tool is pressed against the surface to be cleaned by hand during cleaning. At this time, the cleaning sheet is moved against the surface to be cleaned while receiving a predetermined pressure from both sides by the hand and the surface to be cleaned, and collects dust from the surface to be cleaned. Users have carefully studied how cleaning sheets are used and found that with wet-type cleaning sheets, the cleaning sheet tends to adhere to the surface to be cleaned, and when the cleaning sheet receives a predetermined pressure, gaps are unlikely to form between the surface to be cleaned and the cleaning sheet, which can capture small dust particles but not large dust particles.

[0005] The present invention has been made in view of the above problems, and provides a wet cleaning sheet that can easily collect dust particles of various sizes. [Means for solving the problem]

[0006] A cleaning sheet according to one embodiment is a wet-type cleaning sheet comprising a first sheet-shaped member, a second sheet-shaped member overlapping the first sheet-shaped member, a joint joining the first sheet-shaped member and the second sheet-shaped member, and at least one of the first sheet-shaped member and the second sheet-shaped member impregnated with a chemical solution. In a wet and compressed state in which the cleaning sheet is impregnated with 300% or more of the chemical solution relative to its weight and is pressed at a pressure of 7.00 kPa to 8.00 kPa, the thickness of the cleaning sheet in a non-jointed region where the joint is not provided is 3.0 times or more the thickness of the cleaning sheet in a jointed region where the joint is provided. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view schematically showing a cleaning tool and a cleaning sheet according to a first embodiment. [Figure 2] FIG. 2 is a plan view of the cleaning sheet according to the first embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view taken along the line AA shown in FIG. [Figure 4] FIG. 4 is a schematic enlarged perspective view of part B shown in FIG. [Figure 5] FIG. 5 is a diagram for explaining the pressed wet state. [Figure 6] FIG. 6 is a photograph showing the side surface of the cleaning sheet 1. [Figure 7] FIG. 7 is a diagram for explaining the measurement of the force required to move the cleaning sheet in a wet pressing state. [Figure 8] FIG. 8 is a schematic cross-sectional view of a cleaning sheet according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (1) Overview of the embodiment At least the following matters will become clear from the description of this specification and the accompanying drawings. A first aspect of the invention is a wet-type cleaning sheet comprising a first sheet-like member, a second sheet-like member overlapping the first sheet-like member, a joint portion joining the first sheet-like member and the second sheet-like member, and at least one of the first sheet-like member and the second sheet-like member impregnated with a chemical solution. In a wet-pressed state in which the cleaning sheet is impregnated with 300% or more of the chemical solution relative to its weight and pressed at a pressure of 7.00 kPa to 8.00 kPa, the thickness of the cleaning sheet in the non-jointed region where the joint portion is not provided is 3.0 times or more the thickness of the cleaning sheet in the jointed region where the joint portion is provided. The outer surface of the cleaning sheet opposite the cleaning surface is placed along a cleaning tool or a hand. Therefore, the outer surface of the cleaning sheet facing the cleaning surface has unevenness due to the difference in thickness between the non-jointed region and the jointed region. The thickness of the non-bonded areas corresponding to the convex parts is more than three times that of the bonded areas corresponding to the concave parts, and because of this large difference, larger dust particles can be captured within the concave parts, while smaller dust particles can be captured by the convex parts in close contact with the cleaning surface.

[0009] The invention according to aspect 2 is the invention according to aspect 1, and has the following features. The difference in thickness between the non-bonded region and the bonded region is 0.3 mm or more and 2.0 mm or less. Typical dimensions of dust and dirt are, for example, 5 μm to 75 μm for dust (JIS dust type 7), 45 μm to 212 μm for sand (JIS silica sand), and 1 mm to 2 mm for breadcrumbs. By having the difference in thickness between the non-bonded region and the bonded region be 0.3 mm or more, the volume of the depression created by the non-bonded region is ensured, making it easier for dust and dirt to be retained in the depression. Furthermore, by having the difference in thickness between the non-bonded region and the bonded region be 2.0 mm or less, dust and dirt can easily hit the fibers that form the bottom of the depression, making it easier for the fibers to retain dust and dirt.

[0010] The invention according to Aspect 3 has the following features in the invention according to Aspect 1 or Aspect 2. The second sheet-shaped member is positioned closer to the cleaning surface than the first sheet-shaped member. The hydrophilicity of the second sheet-shaped member is lower than that of the first sheet-shaped member. According to this aspect, the first sheet-shaped member has high hydrophilicity and easily retains chemical solution. Therefore, when the second sheet-shaped member is used as the cleaning surface, the chemical solution is gradually released from the first sheet-shaped member located on the inside, allowing the chemical solution to be continuously released.

[0011] The invention according to Aspect 4 is the invention according to any one of Aspects 1 to 3, and has the following features: The first sheet-like member is a nonwoven fabric. The second sheet-like member is a fiber bundle. According to this aspect, the second sheet-like member, which is a fiber bundle, entangles and holds dust on the cleaning surface, and the first sheet-like member, which is a nonwoven fabric, ensures the rigidity of the cleaning sheet, making it easier to maintain the planar shape of the cleaning sheet.

[0012] The invention according to aspect 5 has the following features in the invention according to aspect 4. The joints are arranged at intervals along the orientation direction of the fibers of the fiber bundle. Between the joints in the orientation direction, cut portions where the fiber bundle is cut are arranged at intervals along the orientation direction. The cut portions are arranged at intervals in an orthogonal direction perpendicular to the orientation direction. The fibers cut by the cut portions form standing portions that can stand upright on the nonwoven fabric using the joints as base points. The fibers arranged between the cut portions in the orthogonal direction are not joined to the nonwoven fabric but are arranged straddling adjacent joints in the orientation direction. According to this aspect, the standing portions stand upright on the first sheet-like member and are likely to come into contact with the cleaning surface, making it easy to collect dust. Furthermore, because fibers straddling the joints are arranged adjacent to the standing portions, dust is likely to become entangled in the fibers and continue to be retained. Furthermore, when the amount of chemical solution in the standing portions decreases as cleaning continues, the chemical solution can continue to be released through the fibers adjacent to the standing portions and spanning the joints, and the fibers of the first sheet-like member that are exposed when the standing portions stand up. Furthermore, the fibers that are arranged spanning the joints are connected to the joints, and the chemical solution can penetrate from the joint side, so the chemical solution can continue to be released.

[0013] The invention according to aspect 6 is the invention according to aspect 5, and has the following features. The length of the upright portions in the orientation direction is 1 mm or more and 30 mm or less. Because the length of the upright portions is 1 mm or more and 30 mm or less, the upright portions move within a range of movement of a radius of 30 mm or less, and the upright portions can fit into the unevenness of the cleaning surface and capture dust. Furthermore, when the upright portions move within a range of movement of a radius of 30 mm or less, the first sheet-like member is exposed in the portions (recesses) where the first sheet-like member is not covered by the upright portions, allowing the nonwoven fabric of the first sheet-like member to perform finishing wiping. Furthermore, if the range of movement of the upright portions is too wide, the dimensions of the portions (recesses) where the first sheet-like member is not covered by the upright portions will increase, and there is a risk that the dust that was once drawn in will escape. However, because the radius of the range of movement of the upright portions is 30 mm or less, which is not too wide, dust can continue to be captured within the recesses.

[0014] The invention according to Aspect 7 is the invention according to any one of Aspects 4 to 6, and has the following features: The first sheet-shaped member is arranged on one outer surface of the cleaning sheet. The second sheet-shaped member is arranged on the other outer surface of the cleaning sheet. According to this aspect, dust can be drawn in by the second sheet-shaped member arranged on the other outer surface of the cleaning sheet, and finishing wiping can be performed by the first sheet-shaped member arranged on one outer surface of the cleaning sheet.

[0015] The invention according to aspect 8 has the following features in the invention according to aspect 7. The force required to place one outer surface of the cleaning sheet against the surface to be cleaned and move it 300 mm in a planar direction in the wet pressing state is 2.0 to 3.0 times the force required to place the other outer surface of the cleaning sheet against the surface to be cleaned and move it 300 mm in a planar direction in the wet pressing state. According to this aspect, since the wiping weight of one outer surface and the other surface differs by more than two times, the user can sense which outer surface is being used for cleaning by feel without visually checking. Furthermore, if the wiping weight of one outer surface and the other surface differs too much, the user may feel that the feel is too different and may feel uncomfortable during use. Since the wiping weight of one outer surface and the other surface is three times or less, the user can use the cleaning sheet with a similar feel while being aware of the difference between the outer surfaces.

[0016] The invention according to Aspect 9 is the invention according to any one of Aspects 4 to 6, and has the following features: The second sheet-shaped members are arranged on both outer surfaces of the cleaning sheet. The first sheet-shaped members are arranged between the second sheet-shaped members. According to this aspect, the first sheet-shaped members ensure the rigidity of the cleaning sheet and maintain its flat state, while the second sheet-shaped members arranged on both sides of the cleaning sheet can draw in dust. Furthermore, because the second sheet-shaped members are arranged on both sides of the cleaning sheet, the user can experience the same feeling when cleaning using either outer surface.

[0017] The invention according to Aspect 10 is the invention according to any one of Aspects 1 to 9, and has the following features. The cleaning sheet is attached to a cleaning tool having a facing surface that extends in a planar direction including a first direction and a second direction and faces a cleaning target. The cleaning sheet has a pair of sheet side portions that are folded along the first-direction edge of the facing surface and engage with the cleaning tool, and a sheet central portion that is disposed on the facing surface between the pair of sheet side portions. A plurality of the joint portions are arranged at intervals in the second direction in the sheet central portion. When wiping using a cleaning tool with a cleaning sheet attached, a user generally moves the cleaning surface in the second direction, moving the cleaning sheet in a direction perpendicular to the fold with the fold positioned at the leading end of the movement direction. At this time, because the joint portions are arranged at intervals in the second direction, the jointed regions and non-jointed regions alternately come into contact with each other, allowing the convex non-jointed portions to contact and draw in dust, and the concave jointed portions to retain dust.

[0018] The invention according to aspect 11 has the following feature in the invention according to aspect 10: At least one of the orientation direction of the fibers of the first sheet-like member and the orientation direction of the fibers of the second sheet-like member is the first direction. According to this aspect, when the cleaning sheet is moved in the second direction to perform a wiping operation, dust becomes more likely to become entangled in the fibers.

[0019] The invention according to aspect 12 is the invention according to aspect 9 or aspect 10, and has the following features. The first sheet-shaped member is arranged over the entire area of ​​the cleaning sheet in the second direction. The second sheet-shaped member is arranged over the entire area of ​​the center of the sheet in the second direction. In the second direction, the outer edge of the second sheet-shaped member is located more inward than the outer edge of the first sheet-shaped member. According to this aspect, since the second sheet-shaped member is arranged over the entire area of ​​the center of the sheet in the second direction, dust can be collected by the fiber bundles of the second sheet-shaped member over the entire area of ​​the center of the sheet in the second direction. Furthermore, the second sheet-shaped member is located more inward than the first sheet-shaped member in the second direction, and an area where the first sheet-shaped member is arranged but the second sheet-shaped member is not arranged is formed on the side of the sheet. This area is thinner than the area where two layers of sheet-shaped members are arranged, making it easier to engage with a cleaning tool and less likely to come off the engaging portion.

[0020] The invention according to Aspect 13 has the following features in the invention according to Aspect 12. The first sheet-like member has compressed portions formed by compressing the first sheet-like member at least in the thickness direction. The compressed portions are provided at least on the side portions of the sheet. According to this aspect, the compressed portions can increase the rigidity of the side portions of the sheet. The rigidity of the cleaning sheet is ensured even in areas where the second sheet-like member is not arranged, making it easier to continue wiping with the cleaning sheet.

[0021] (2) Cleaning sheet according to the first embodiment The cleaning sheet 1 according to the first embodiment will be described below with reference to the drawings. In the following description of the drawings, identical or similar parts are denoted by identical or similar reference numerals. However, it should be noted that the drawings are schematic, and the dimensional ratios and the like may differ from those of the actual product. Therefore, specific dimensions and the like should be determined with reference to the following description. Furthermore, the drawings may include parts with different dimensional relationships and ratios.

[0022] The cleaning sheet 1 may be attached to the cleaning tool 200 when in use, or may be a cleaning sheet that is not attached to the cleaning tool 200 and is used as a standalone sheet. The cleaning sheet 1 of this embodiment is attached to the cleaning tool 200 when in use. An example of the cleaning tool 200 is the cleaning tool 200 shown in FIG. 1. FIG. 1 is a perspective view that schematically shows the cleaning tool 200 according to the embodiment and the cleaning sheet 1 attached to the cleaning tool 200. The cleaning tool 200 has a facing surface 210 that faces the object to be cleaned. The facing surface 210 may be provided on the cleaning head 201. The facing surface 210 extends in a planar direction that includes the first direction D1 and the second direction D2. The cleaning sheet 1 comes into contact with the facing surface 210, and the abutting cleaning sheet 1 cleans the object to be cleaned. The facing surface 210 may be a rectangular surface.

[0023] The cleaning tool 200 may have an engaging portion 230 that detachably engages with the cleaning sheet 1 at a location other than the facing surface 210, such as a surface opposite the facing surface 210. The engaging portion 230 detachably engages with the cleaning sheet 1 folded back along an edge of the facing surface 210 extending in the first direction D1. The edge of the facing surface 210 extending in the first direction D1 is an edge of the rectangular surface of the facing surface 210 in the second direction D2. The cleaning tool 200 may have a gripping portion 250 that is connected to the facing surface 210 and gripped by a user. The length of the facing surface 210 in the first direction D1 may be longer than the length of the facing surface 210 in the second direction D2. In this embodiment, the length of the facing surface 210 in the first direction D1 is 2.0 times or more the length of the facing surface 210 in the second direction D2. In a configuration in which the length of opposing surface 210 in first direction D1 is long in second direction D2 of opposing surface 210, cleaning tool 200 may be designed assuming that a user will move cleaning tool 200 back and forth in second direction D2. The cleaning tool may be for flooring (with a long grip so that the user can clean the floor while standing) or may be for handheld use (with a short grip so that the user can clean an area that can be reached by hand).

[0024] The cleaning sheet 1 is a sheet-like fibrous structure that cleans surfaces such as floors, furniture, and home appliances by wiping away dust and dirt. Fig. 2 is a plan view of the cleaning sheet 1. Fig. 3 is a schematic cross-sectional view taken along line AA in Fig. 2. Fig. 4 is an enlarged perspective view of part B in Fig. 2. For ease of explanation, the cross-sectional view shows components spaced apart in the thickness direction T, but in an actual product, the components may abut against each other. The cleaning sheet 1 has a planar direction including a first direction D1 and a second direction D2, and a thickness direction T perpendicular to the planar direction. The cleaning sheet 1 has a pair of outer surfaces that are surfaces on the outside of the thickness direction T. The outer surfaces extend in the planar direction and have a first surface 21 and a second surface 22. The second surface 22 is the surface opposite the first surface 21. Both the first surface 21 and the second surface 22 may constitute wiping surfaces for wiping the surface. A user can clean with first surface 21 by bringing second surface 22 into contact with opposing surface 210 of cleaning tool 200, and can also clean with second surface 22 by bringing first surface 21 into contact with opposing surface 210 of cleaning tool 200. In other words, dust and dirt on the cleaning target can be wiped off with both first surface 21 and second surface 22. The plan view shown in Figure 2 is a view from the first surface 21 side.

[0025] The side portions of the cleaning sheet 1 in the second direction D2 are folded back along the edges of the facing surface 210 extending in the first direction D1, and are configured to detachably engage with the cleaning tool 200. The cleaning sheet 1 may have a sheet center portion R1 disposed on the facing surface 210, and sheet side portions R2 disposed on both sides of the sheet center portion R1 in the second direction D2, folded back along the edges of the facing surface 210 extending in the first direction D1, and detachably engage with the cleaning tool 200. The sheet center portion R1 is located in the center of the cleaning sheet 1 in the second direction D2, and the sheet side portions R2 are located on both sides of the sheet center portion R1 in the second direction D2. Note that the ranges of the sheet center portion R1 and the sheet side portions R2 vary depending on the dimensions of the facing surface 210, and therefore may vary depending on the cleaning sheet 1. However, the sheet center portion R1 is a portion that includes the center of the cleaning sheet 1 in the second direction D2, and the sheet side portions R2 may be a certain range extending inward in the second direction D2 from the side edges in the second direction D2 of the cleaning sheet 1. The length in the second direction D2 of each sheet side portion R2 may be shorter than the length in the second direction D2 of the sheet center portion R1.

[0026] The cleaning sheet 1 has a plurality of sheet-shaped members. The sheet-shaped members may be members whose dimensions in the planar directions (first and second directions) are longer than their dimensions in the thickness direction T. The sheet-shaped members may be fiber sheets such as nonwoven fabrics or woven fabrics, or fiber bundles formed by collecting fibers. The sheet-shaped members have a first sheet-shaped member 11 and a second sheet-shaped member 12 overlapping the first sheet-shaped member 11. The first sheet-shaped member 11 and the second sheet-shaped member 12 overlap in the thickness direction T. The sheet-shaped member may include at least the first sheet-shaped member 11 and the second sheet-shaped member 12, and may further include other sheet-shaped members. The first sheet-shaped member 11 and the second sheet-shaped member 12 are joined by a joint 31. Examples of the joint 31 include a welded portion such as a thermally welded portion, or a bonded portion using an adhesive. The cleaning sheet 1 has a bonded region R11 where a bonded portion 31 is provided in a plan view, and a non-bonded region R12 where no bonded portion 31 is provided in a plan view. The non-bonded region R12 includes not only a region where the first sheet-shaped member 11 and the second sheet-shaped member 12 overlap without being bonded, but also a region where only the first sheet-shaped member 11 is arranged and a region where only the second sheet-shaped member 12 is arranged.

[0027] The cleaning sheet 1 is a wet-type cleaning sheet 1 impregnated with a chemical solution. The chemical solution is a cleaning chemical, and examples of its components include water, a surfactant, alcohol, and glycerin. The cleaning sheet 1 may be impregnated with 300% or more of the chemical solution based on its weight. The chemical solution may be impregnated into at least one of the first sheet-shaped member 11 and the second sheet-shaped member 12, or may be impregnated into both the first sheet-shaped member 11 and the second sheet-shaped member 12. To measure the amount of impregnated chemical solution, one cleaning sheet impregnated with the chemical solution is removed from the package and the weight of that sheet is measured. Next, the cleaning sheet is washed with distilled water to rinse off the chemical solution, and then the cleaning sheet is dried. The weight of the dried cleaning sheet is measured. The amount of impregnated chemical solution can be calculated by the difference between the initial weight of the cleaning sheet and the gravity of the cleaning sheet after drying. When the amount of chemical solution impregnated as measured in this manner is 300% or more of the weight of the cleaning sheet after drying, it is considered that 300% or more of the chemical solution is impregnated into the cleaning sheet relative to its weight.

[0028] A wet cleaning sheet 1 adheres more closely to the surface to be cleaned than a dry cleaning sheet. As a result, gaps are less likely to form between the surface of the surface to be cleaned and the cleaning sheet 1, which can capture small dust particles but not large dust particles. The cleaning sheet 1 of this embodiment is configured to easily capture dust particles of various sizes, both large and small, compared to wet cleaning sheets. Next, the configuration for easily capturing dust particles of various sizes will be described in detail.

[0029] When wiping a surface to be cleaned with the cleaning sheet 1, the cleaning sheet 1 is pressed from both sides by the cleaning tool (or hand) and the surface to be cleaned. The applicant's extensive research has revealed that the pressure the cleaning sheet 1 receives during this wiping cleaning is generally 7.00 kPa to 8.00 kPa. In the cleaning sheet 1 of this embodiment, the thickness T12 of the cleaning sheet 1 in the non-bonded region R12 in a wet, pressed state is 3.0 times or more the thickness T11 of the cleaning sheet 1 in the bonded region R11. The outer surface of the cleaning sheet 1 opposite the surface to be cleaned is placed along the cleaning tool or hand. Therefore, the outer surface of the cleaning sheet 1 facing the surface to be cleaned has irregularities due to the difference in thickness between the non-bonded region R12 and the bonded region R11. The thickness of the non-bonding area R12 corresponding to the convex portion is more than three times that of the bonding area R11 corresponding to the concave portion, and because of this large difference, larger dust particles can be captured within the concave portion, and smaller dust particles can be captured by the convex portion in close contact with the cleaning surface.

[0030] The pressure-wet state is a state in which the cleaning sheet 1 is impregnated with 300% or more of the chemical solution relative to its weight and is pressed with a pressure of 7.00 kPa to 8.00 kPa. FIG. 5 is a diagram illustrating the pressure-wet state. The pressure-wet state can be reproduced, for example, by the following method. First, the cleaning sheet 1 is impregnated with 300% or more of the chemical solution relative to its weight. The chemical solution can be, for example, a mixture of 94% water, 5% alcohol, 0.5% surfactant, and 0.5% antiseptic. Next, as shown in FIG. 5(A), both sides of the cleaning sheet 1 impregnated with the chemical solution are covered with plate-like members 401. The plate-like members 401 may be any member that does not absorb the chemical solution and is not damaged by a pressure of 7.00 kPa to 8.00 kPa; for example, a metal ruler can be used. Next, as shown in FIG. 5(B), the plate-shaped member 401 is pressed against the cleaning sheet 1 from both sides, applying a pressure of 7.00 kPa to 8.00 kPa to the cleaning sheet 1. The means for applying this pressure is not particularly limited, but for example, the plate-shaped member 401 may be clamped with clips to press the cleaning sheet 1 from both sides. FIG. 5(B) shows the pressed and wet state. The thickness in the pressed and wet state can be measured by taking a photograph of the cleaning sheet from the side in the pressed and wet state and enlarging the image. The difference between the thickness T12 of the cleaning sheet 1 in the non-bonded region R12 and the thickness T11 of the cleaning sheet 1 in the bonded region R11 can be compared based on the maximum thickness of each region. FIG. 6 is a photograph showing the side of the cleaning sheet 1 in the pressed and wet state according to this embodiment.

[0031] The difference between the thickness T12 of the non-bonded region R12 and the thickness T11 of the bonded region R11 may be 0.3 mm or more and 2.0 mm or less. Typical dimensions of dust and dirt are, for example, 5 μm to 75 μm for dust (JIS dust type 7), 45 μm to 212 μm for sand (JIS silica sand), and 1 mm to 2 mm for breadcrumbs. By making the difference between the thickness of the non-bonded region and the thickness of the bonded region 0.3 mm or more, the volume of the recess created by the non-bonded region R12 is ensured, making it easier for dust and dirt to be retained in the recess. Furthermore, by making the difference between the thickness T12 of the non-bonded region R12 and the thickness T11 of the bonded region R11 2.0 mm or less, dust and dirt can easily reach the fibers that form the bottom of the recess, making it easier for the fibers to retain dust and dirt. The pitch of the joints 31 in the first direction D1 may be 10 mm or more and 50 mm or less, and the pitch of the joints 31 in the second direction D2 may be 10 mm or more and 60 mm or less. The thickness T12 of the cleaning sheet 1 may be 3.0 times or more, and preferably 4.0 times or more, the thickness T11 of the cleaning sheet 1 in the joint region R11. The thickness T12 of the cleaning sheet 1 may be 10.0 times or less, and preferably 7.0 times or less, the thickness T11 of the cleaning sheet 1 in the joint region R11.

[0032] The second sheet-shaped member 12 may be positioned closer to the cleaning surface than the first sheet-shaped member 11. The cleaning surface refers to at least one of the first and second surfaces 21 and 22 that constitute the outer surfaces of the cleaning sheet 1. Preferably, the second sheet-shaped member 12 may be positioned on at least one of the first and second surfaces 21 and 22. The hydrophilicity of the second sheet-shaped member 12 may be lower than that of the first sheet-shaped member 11. The first sheet-shaped member 11 has high hydrophilicity and easily retains chemical solution. Therefore, when the second sheet-shaped member 12 is used as the cleaning surface, the chemical solution is gradually released from the first sheet-shaped member 11 located inside, allowing the chemical solution to be continuously released. The hydrophilicity can be measured and compared using the Byreck method of JIS 1907.

[0033] Various configurations can be adopted to make the hydrophilicity of the first sheet-like member 11 higher than that of the second sheet-like member 12, but examples include a configuration in which the weight of the hydrophilic fibers in the first sheet-like member 11 is higher than the weight of the hydrophilic fibers in the second sheet-like member 12, and a configuration in which the weight of the hydrophobic fibers in the second sheet-like member 12 is higher than the weight of the hydrophobic fibers in the first sheet-like member 11.

[0034] The first sheet-shaped member 11 and the second sheet-shaped member 12 may be made of any of fiber bundles, nonwoven fabric, and woven fabric. Preferably, the first sheet-shaped member 11 is nonwoven fabric, and the second sheet-shaped member 12 is fiber bundles. According to this aspect, the second sheet-shaped member 12, which is a fiber bundle, entangles and holds dust on the cleaning surface, and the first sheet-shaped member 11, which is a nonwoven fabric, ensures the rigidity of the cleaning sheet 1, making it easier to maintain the planar shape of the cleaning sheet 1. The fiber bundles are bundles of fibers that are continuous in a certain direction. The direction in which the fibers in the fiber bundles extend is the fiber orientation direction.

[0035] In the cleaning sheet 1 attached to the cleaning tool 200, the joints 31 may be spaced apart in the second direction D2 at the center R1 of the sheet. When using the cleaning tool 200 to perform a wiping operation, the user generally moves the cleaning surface in the second direction, moving the cleaning sheet in a direction perpendicular to the fold with the fold positioned at the leading edge of the movement direction. Because the joints 31 are spaced apart in the second direction, the joint regions R11 and the non-joint regions R12 alternately come into contact with each other, allowing the non-joint regions, which have a convex shape, to contact dust, and the joint regions R11, which have a concave shape, to retain dust. The form in which the joints 31 are spaced apart in the second direction may be any form in which the joints 31 are spaced apart in the second direction D2 on an imaginary line parallel to the second direction D2 (e.g., the cross section shown in FIG. 3 ).

[0036] In the cleaning sheet 1 attached to the cleaning tool 200, at least one of the orientation direction of the fibers of the first sheet-shaped member 11 and the orientation direction of the fibers of the second sheet-shaped member 12 may be the first direction D1. According to this aspect, when the cleaning sheet 1 is moved in the second direction D2 to perform a wiping operation, dust becomes more likely to become entangled in the fibers. Preferably, both the orientation direction of the fibers of the second sheet-shaped member 12 and the orientation direction of the fibers of the second sheet-shaped member 12 may be the first direction D1.

[0037] In the cleaning sheet 1 attached to the cleaning tool 200, the first sheet-shaped member 11 may be disposed over the entire area of ​​the cleaning sheet 1 in the second direction D2, and the second sheet-shaped member 12 may be disposed over the entire area of ​​the sheet center in the second direction. In the second direction, the outer edge of the second sheet-shaped member 12 may be located more inward than the outer edge of the first sheet-shaped member 11. Because the second sheet-shaped member 12 is disposed over the entire area of ​​the sheet center R1 in the second direction D2, the fiber bundles of the second sheet-shaped member 12 can sweep in dust over the entire area of ​​the sheet center R1 in the second direction D2. Furthermore, the second sheet-shaped member 12 is located more inward than the first sheet-shaped member 11 in the second direction D2, and an area where the first sheet-shaped member 11 is disposed but the second sheet-shaped member 12 is not disposed is formed in the sheet side portion R2. This region is thinner than the region where the two layers of sheet-like member are arranged, and is therefore easier to engage with the cleaning tool and less likely to come off the engaging portion 230.

[0038] In this embodiment, the second sheet-like member 12 is disposed across the entire sheet center portion R1 and a portion of the sheet side portions R2 in the second direction D2. Only the first sheet-like member 11 is disposed outside the outer edge of the second sheet-like member 12 in the second direction D2. In the region outside the second sheet-like member 12 in the second direction D2, cut portions 35 may be formed in the first sheet-like member 11. The cut portions 35 are portions where the first sheet-like member 11 is cut, and may be disposed at intervals in the first direction D1 and the second direction D2. The cut portions 35 are provided only in the sheet side portions R2, not in the sheet center portion R1. This configuration ensures the rigidity of the sheet center portion R1 while reducing the rigidity of the sheet side portions R2, thereby achieving both the effect of maintaining the shape of the cleaning sheet 1 during cleaning and the ease of engagement with the engagement portion 230 of the cleaning tool 200.

[0039] In the cleaning sheet 1 attached to the cleaning tool 200, the first sheet-like member 11 may have compressed portions 37 formed by compressing the first sheet-like member 11 at least in the thickness direction. The compressed portions 37 may be provided at least on the sheet side portions R2. According to this embodiment, the compressed portions 37 can increase the rigidity of the sheet side portions R2. The rigidity of the cleaning sheet 1 is ensured even in areas where the second sheet-like member 12 is not disposed, making it easier to continue wiping with the cleaning sheet 1. The compressed portions 37 may be at least portions where the first sheet-like member 11 is compressed in the thickness direction. In this embodiment, the compressed portions 37 are formed together with the joint portions. More specifically, by pressing the first sheet-like member 11 and the second sheet-like member 12 in the thickness direction to form a welded portion, the joint portions 31 can be formed in the areas where the first sheet-like member 11 and the second sheet-like member 12 overlap, and the compressed portions 37 can be formed in the areas where only the first sheet-like member 11 is disposed. Therefore, the joint portion 31 may be connected to the compressed portion 37. In a modified example, the compressed portion 37 may be formed separately from the joint portion 31.

[0040] The joints 31 may be arranged at intervals along the fiber orientation direction of the fiber bundle. Between the joints 31 in the orientation direction, cut sections 32, where the fiber bundle is cut, may be arranged at intervals along the orientation direction. The cut sections 32 may be arranged at intervals in an orthogonal direction perpendicular to the orientation direction. The fibers cut by the cut sections may form standing sections 33 that can stand up against the nonwoven fabric using the joints as base points. The fibers arranged between the cut sections 32 in the orthogonal direction may be arranged across adjacent joints 31 in the orientation direction without being joined to the nonwoven fabric. FIG. 4(A) shows a state in which the standing sections 33 are not standing up, and FIG. 4(B) shows a state in which the standing sections 33 are standing up. According to this embodiment, the standing sections 33 stand up against the first sheet-like member 11 and easily come into contact with the cleaning surface, making it easy to collect dust. Furthermore, because fibers 34 are arranged adjacent to the standing portions 33 and straddling the joints 31, dust tends to become entangled in the fibers, and the fibers tend to continue to hold the dust. Furthermore, when the amount of chemical solution in the standing portions 33 decreases as cleaning continues, the chemical solution can continue to be released through the fibers 34 adjacent to the standing portions 33 and straddling the joints, and the fibers of the first sheet-like member 11 that are exposed when the standing portions 33 stand up. Furthermore, the fibers 34 arranged straddling the joints 31 are connected to the joints 31, and the chemical solution from the joints 31 side penetrates them, so the chemical solution can continue to be released.

[0041] The length of the upright portions 33 in the orientation direction may be 1 mm or more and 30 mm or less. Because the length of the upright portions 33 is 1 mm or more and 30 mm or less, the upright portions 33 can move within a range of movement with a radius of 30 mm or less, allowing the upright portions 33 to fit into the unevenness of the cleaning surface and capture dust. Furthermore, when the upright portions 33 move within a range of movement with a radius of 30 mm or less, the first sheet-like member 11 is exposed in the areas (recesses) where the first sheet-like member 11 is not covered by the upright portions 33, allowing the nonwoven fabric of the first sheet-like member 11 to perform finishing wiping. Furthermore, if the range of movement of the upright portions 33 is too wide, the dimensions of the areas (recesses) where the first sheet-like member 11 is not covered by the upright portions 33 will increase, which may result in dust being drawn in and released. However, because the radius of the range of movement of the upright portions 33 is 30 mm or less, which is not too wide, dust can continue to be captured within the recesses.

[0042] In this embodiment, the orientation direction of the fibers of the fiber bundle is the first direction D1, and the orthogonal direction is the second direction. The joints 31 are arranged at intervals in the first direction D1. The joints 31 are linear and extend from the center of the cleaning sheet 1 in the second direction D2 toward the outside in the second direction D2 while being inclined with respect to the second direction D2. The cut portions 32 are arranged between the joints 31 in the first direction D1. The joints 31 are discontinuously arranged linearly and extend from the center of the cleaning sheet 1 in the second direction D2 toward the outside in the second direction D2 while being inclined with respect to the second direction D2. The joints 31 and the cut portions 32 are arranged alternately in the first direction D1. The outer edges of the joints 31 in the second direction D2 reach the outer edges of the second sheet-like member 12 in the second direction D2. The outer edges of the cut portions 32 are located more inward in the second direction D2 than the outer edges of the joints 31 in the second direction D2.

[0043] A first sheet-like member 11 may be arranged on one outer surface of the cleaning sheet 1, and a second sheet-like member 12 may be arranged on the other outer surface of the cleaning sheet 1. According to this embodiment, the second sheet-like member 12 arranged on the other outer surface of the cleaning sheet 1 draws in dust, and the first sheet-like member 11 arranged on one outer surface of the cleaning sheet performs finishing wiping. In this embodiment, the first sheet-like member 11 is arranged on the entire first surface 21, and the second sheet-like member 12 and the first sheet-like member 11 are arranged on the second surface 22.

[0044] The force required to place one outer surface of the cleaning sheet 1 against the surface to be cleaned and move it 300 mm in a planar direction in a wet pressed state may be 2.0 to 3.0 times the force required to place the other outer surface of the cleaning sheet against the surface to be cleaned and move it 300 mm in a planar direction in a wet pressed state. Because the wiping weight of one outer surface and the other surface differs by more than two times, the user can sense which outer surface is being used for cleaning by feel without visually checking. Furthermore, if the wiping weight of one outer surface and the other surface differs too much, the user may feel that the feel is too different and may experience discomfort during use. Because the wiping weight of one outer surface and the other surface is no more than three times that of the other, the user can use the cleaning sheet with a similar feel while being aware of the difference in the outer surfaces.

[0045] The force required to move the cleaning sheet 1 in a wet, compressed state can be measured by the following method. Figure 7 is a diagram illustrating the measurement of the force required to move the cleaning sheet 1 in a wet, compressed state. An autograph 301 is used as the measuring device. The lower chuck of the autograph 301 is removed, and flooring 302 is set on the autograph as the cleaning surface. A level is used to set the surface of the flooring 302 at 0 degrees. A string is threaded through the hole in a hook 303 fixed to the flooring 302, and one end of the string 304 is clamped in the upper chuck 305 of the autograph 301. The distance between the upper chuck 305 of the autograph 301 and the hole in the hook 303 is 300 mm. A cleaning sheet 1 impregnated with 300% or more of the chemical solution is attached to the cleaning head 201. The other end of the string 304 is branched into two, and metal fittings 306 are attached to the two ends. The metal fittings 306 are then attached to the engagement portions of the cleaning head 201. The metal fittings 306 are placed at intervals in a direction perpendicular to the direction in which the cleaning sheet 1 is pulled. A weight 307 is placed on the cleaning head 201 so that the pressure applied to the cleaning sheet 1 is 7.00 kPa to 8.00 kPa. In this state, the cleaning sheet 1 is pulled via the cleaning head 201 using the autograph 301. The pulling speed is 500 mm / min, the pulling distance is 300 mm, and the maximum measured value is taken as the force (unit: N) that moves the cleaning sheet 1 in a wet, pressed state. When measuring the next cleaning sheet moving force, the flooring surface is wiped with a dry cloth.

[0046] (3) Cleaning sheet according to the second embodiment Next, the cleaning sheet according to the second embodiment will be described in detail. FIG. 8 is a schematic cross-sectional view of a cleaning sheet 1X according to the second embodiment. The cross-sectional view in FIG. 8 is taken along line AA in FIG. 2. In the cleaning sheet 1X according to the second embodiment, second sheet-like members 12 are arranged on both outer surfaces of the cleaning sheet 1. The first sheet-like members 11 are arranged between the second sheet-like members 12. In the cleaning sheet 1X according to the second embodiment, the first and second surfaces have the same shape. According to this aspect, the first sheet-like members 11 ensure the rigidity of the cleaning sheet and maintain its flat state, while the second sheet-like members 12 arranged on both sides of the cleaning sheet can attract dust. Furthermore, because the second sheet-like members 12 are arranged on both sides of the cleaning sheet, the user can experience the same feeling when cleaning using either outer surface. Furthermore, when the second sheet-like member 12 has a raised portion, the first sheet-like member 11 is exposed in the portions (recesses) on either outer surface where the first sheet-like member 11 is not covered by the raised portion, and finishing wiping can be performed using the nonwoven fabric of the first sheet-like member 11.

[0047] Although the present invention has been described in detail using the above-described embodiments, it will be apparent to those skilled in the art that the present invention is not limited to the embodiments described herein. The present invention can be implemented in modified and altered forms without departing from the spirit and scope of the present invention as defined by the claims. Therefore, the description in this specification is intended to be illustrative and does not have any limiting meaning on the present invention. [Explanation of symbols]

[0048] 1. 1X: Cleaning sheet 11: First sheet-like member 12: Second sheet-like member 21: 1st surface (outer surface) 22: 2nd surface (outer surface) 31: Joint 32: Cutting section 33: Standing part 34: Fibers spanning the joint 35: Notch 37: Compression section 200: Cleaning tools 201: Cleaning head 210: Opposite surface 230: Engagement part 250: Grip part R1: Center of seat R2: Seat side R11: Junction area R12: Non-bonded area D1: First direction (orientation direction) D2 :Second direction T: Thickness direction

Claims

1. a first sheet-like member; a second sheet-like member overlapping the first sheet-like member; a joint portion at which the first sheet-like member and the second sheet-like member are joined; a wet cleaning sheet in which at least one of the first sheet-shaped member and the second sheet-shaped member is impregnated with a chemical solution, a cleaning sheet in which the cleaning sheet is impregnated with a chemical solution that is 300% or more of its weight, and in a wet pressed state in which the cleaning sheet is pressed at a pressure of 7.00 kPa to 8.00 kPa, the thickness of the cleaning sheet in a non-bonded region where no bonded part is provided is 3.0 times or more the thickness of the cleaning sheet in a bonded region where the bonded part is provided.

2. The cleaning sheet according to claim 1 , wherein the difference in thickness between the non-bonded region and the bonded region is 0.3 mm or more and 2.0 mm or less.

3. the second sheet-shaped member is disposed closer to the cleaning surface than the first sheet-shaped member, 3. The cleaning sheet according to claim 1, wherein the second sheet-shaped member has a lower hydrophilicity than the first sheet-shaped member.

4. the first sheet-like member is a nonwoven fabric, The cleaning sheet according to claim 1 or 2, wherein the second sheet-like member is a fiber bundle.

5. The joints are arranged at intervals along the orientation direction of the fibers of the fiber bundle, cut portions, at which the fiber bundles are cut, are arranged at intervals along the orientation direction between the joint portions in the orientation direction, The cut portions are arranged at intervals in an orthogonal direction orthogonal to the orientation direction, the fibers cut by the cutting portion constitute standing portions that can stand up relative to the nonwoven fabric using the joining portions as base points, The cleaning sheet according to claim 4 , wherein the fibers arranged between the cut portions in the orthogonal direction are not joined to the nonwoven fabric, but are arranged so as to straddle the joined portions adjacent to each other in the orientation direction.

6. The cleaning sheet according to claim 5 , wherein the length of the upright portions in the orientation direction is 1 mm or more and 30 mm or less.

7. the first sheet-shaped member is disposed on one outer surface of the cleaning sheet; The cleaning sheet according to claim 4 , wherein the second sheet-shaped member is disposed on the other outer surface of the cleaning sheet.

8. 8. The cleaning sheet according to claim 7, wherein a force required to move one outer surface of the cleaning sheet in the wet pressed state in a planar direction by 300 mm while contacting the cleaning surface with one outer surface of the cleaning sheet is 2.0 to 3.0 times greater than a force required to move the other outer surface of the cleaning sheet in the wet pressed state in a planar direction by 300 mm while contacting the cleaning surface with the other outer surface of the cleaning sheet.

9. the second sheet-like members are disposed on both outer surfaces of the cleaning sheet; The cleaning sheet according to claim 7 , wherein the first sheet-shaped members are disposed between the second sheet-shaped members.

10. The cleaning sheet is attached to a cleaning tool having a surface that extends in a planar direction including a first direction and a second direction and faces an object to be cleaned, the cleaning sheet has a pair of sheet side portions folded back along edges of the opposing surface in the first direction to be engaged with the cleaning tool, and a sheet center portion disposed on the opposing surface between the pair of sheet side portions, The cleaning sheet according to claim 1 or 2, wherein a plurality of the joints are arranged at intervals in the second direction in the central portion of the sheet.

11. The cleaning sheet according to claim 10 , wherein at least one of the orientation direction of the fibers of the first sheet-like member and the orientation direction of the fibers of the second sheet-like member is the first direction.

12. the first sheet-shaped member is disposed over the entire area of ​​the cleaning sheet in the second direction, the second sheet-like member is disposed over the entire area of ​​the center portion of the seat in the second direction, The cleaning sheet according to claim 10 , wherein an outer edge of the second sheet-shaped member is located more inward than an outer edge of the first sheet-shaped member in the second direction.

13. The first sheet-like member has a compressed portion formed by compressing the first sheet-like member at least in a thickness direction, The cleaning sheet according to claim 12, wherein the compressed portions are provided at least on the side portions of the sheet.

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