Cleaning sheet

Abstract

To provide a cleaning sheet for improving operability in an attachment / detachment work of the cleaning sheet with respect to a cleaning tool.SOLUTION: A cleaning sheet (1) is used by being attached to a cleaning tool having a cleaning surface which extends in a plane direction including a first direction and a second direction and opposes to a cleaning object. Side parts of the cleaning sheet in the second direction (D2) are folded along end edges of the cleaning surface (210) extending in the first direction (D1) so as to be detachably engaged with the cleaning tool. Cantilever bending resistance of the cleaning sheet in the second direction is higher than the cantilever bending resistance of the cleaning sheet in the first direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cleaning sheet that is attached to a cleaning tool having a cleaning surface that faces an object to be cleaned.

[0002] Patent Document 1 discloses a cleaning sheet that is attached to a cleaning tool having a cleaning surface facing the object to be cleaned. The cleaning surface of the cleaning tool extends in a planar direction including a first direction and a second direction that are perpendicular to each other. The cleaning sheet has a sheet center that is placed on the cleaning surface and sheet side portions that are provided on both sides of the sheet center in the second direction.

[0003] When attached to the cleaning tool, the center of the sheet is positioned facing the surface to be cleaned, and the side portions of the sheet are folded back along the edges of the surface to be cleaned that extend in a first direction, and are removably engaged with the cleaning tool. When a user performs a wiping operation using a cleaning tool with a cleaning sheet attached in this way, the user generally moves the surface to be cleaned in a second direction, and moves the cleaning sheet in a direction perpendicular to the fold with the fold positioned at the leading end of the movement direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-100950 Summary of the Invention

[0005] When attaching the cleaning sheet of Patent Document 1 to a cleaning tool, the cleaning surface is placed on the center of the sheet, and the side portions of the sheet are folded back starting from folds along the edges of the cleaning surface in the first direction. The side portions of the sheet of Patent Document 1 have embossed areas with embossed portions arranged in a strip shape extending in the first direction. The embossed areas are arranged from near the boundaries between the center and side portions of the sheet toward the outside in the second direction. Therefore, the cleaning sheet of Patent Document 1 is prone to forming deformation base points extending in the first direction due to the boundaries of the embossed areas. Therefore, deformation of the cleaning sheet when folded back starting from the edges of the cleaning surface in the first direction is prone to propagate in the first direction due to the deformation base points at the boundaries of the embossed areas. Therefore, while it is easy to fold the cleaning sheet continuously in the first direction, it is difficult to propagate the folding force to the edges of the cleaning sheet in the second direction, making it difficult to fold back to the edges of the side portions of the sheet in the second direction. Furthermore, when unfolding the cleaning sheet to remove it from the cleaning tool, the deformation caused by the creases due to the folds and the deformation origin at the boundary of the embossed area makes it easy for the deformation caused by unfolding the cleaning sheet to propagate in the first direction, but makes it difficult for the deformation caused by unfolding to propagate to the end of the cleaning sheet in the second direction, making it difficult to unfold the sheet to the end of the side in the second direction.

[0006] The present invention has been made in view of the above problems, and provides a cleaning sheet that can improve the operability of attaching and detaching the cleaning sheet to and from a cleaning tool. [Means for solving the problem]

[0007] The cleaning sheet according to the first aspect is attached to a cleaning tool having a cleaning surface that extends in a planar direction including a first direction and a second direction and faces an object to be cleaned. The side portion of the cleaning sheet in the second direction is folded back along an edge of the cleaning surface that extends in the first direction, and is configured to removably engage with the cleaning tool. The cantilever bending resistance of the cleaning sheet in the second direction is higher than the cantilever bending resistance of the cleaning sheet in the first direction.

[0008] A cleaning sheet according to a second aspect is attached to a cleaning tool having a cleaning 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 side portion in the second direction that is folded back along an edge of the cleaning surface that extends in the first direction, and is configured to removably engage with the cleaning tool. The tensile strength of the cleaning sheet in the second direction is higher than the tensile strength of the cleaning sheet in the first direction.

[0009] A cleaning sheet according to a third aspect is attached to a cleaning tool having a cleaning 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 side portion in the second direction that is folded back along an edge of the cleaning surface that extends in the first direction, and is configured to removably engage with the cleaning tool. The fibers of the cleaning sheet are oriented in the second direction. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view schematically showing a cleaning tool and a cleaning sheet according to an embodiment. [Figure 2] FIG. 2 is a plan view of the cleaning sheet according to the embodiment. [Figure 3] FIG. 3 is a diagram schematically illustrating a cleaning sheet according to an embodiment. [Figure 4] FIG. 4 is a cross-sectional photograph of the cleaning sheet according to the embodiment. [Figure 5] FIG. 5 is a photograph showing a plan view of the cleaning sheet according to the embodiment. [Figure 6] FIG. 6 is a diagram showing an example of a folding manner of the cleaning sheet according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] (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 the cleaning sheet according to the first aspect. The cleaning sheet is attached to a cleaning tool that extends in a planar direction including a first direction and a second direction and has a cleaning surface facing an object to be cleaned. The side portions of the cleaning sheet in the second direction are folded back along the edges of the cleaning surface extending in the first direction, and are configured to detachably engage with the cleaning tool. The cantilever bending resistance of the cleaning sheet in the second direction is higher than the cantilever bending resistance of the cleaning sheet in the first direction. When attaching the cleaning sheet to a cleaning tool, the side portions of the cleaning sheet in the second direction (hereinafter referred to as sheet side portions) are folded back along the edges of the cleaning surface extending in the first direction. The cleaning sheet has a high cantilever bending resistance in the second direction, and therefore easily transmits force along the second direction. Therefore, when a folding force is applied to the sheet side portions, the force is easily transmitted to the ends of the cleaning sheet in the second direction, making it easy to fold back the entire sheet side portions in the second direction. The deformation of the sheet side portions as they fold back is also propagated in the first direction by the edges of the cleaning surface extending in the first direction, allowing the entire sheet side portions to be folded back smoothly. Furthermore, when removing the cleaning sheet, a force to unfold the cleaning sheet is applied to the sheet side portions. At this time, this force is easily propagated to the entire sheet side portions in the second direction, making it easier to fold back the entire sheet side portions in the second direction. The deformation of the sheet side portions as they unfold is also propagated in the first direction by the creases created by the folds, allowing the entire sheet side portions to be unfolded smoothly. This allows the cleaning sheet to be smoothly attached to and detached from the cleaning tool, improving the operability of the cleaning sheet attachment and detachment process.

[0012] Aspect 2 of the invention relates to a cleaning sheet according to the second aspect. The cleaning sheet is attached to a cleaning tool that extends in a planar direction including a first direction and a second direction and has a cleaning surface facing an object to be cleaned. The side portions of the cleaning sheet in the second direction are folded back along the edges of the cleaning surface extending in the first direction, and are configured to detachably engage with the cleaning tool. The tensile strength of the cleaning sheet in the second direction is higher than the tensile strength of the cleaning sheet in the first direction. When attaching the cleaning sheet to the cleaning tool, the side portions of the sheet are folded back along the edges of the cleaning surface extending in the first direction. The cleaning sheet has high tensile strength in the second direction, is less likely to stretch in the second direction, and easily transmits force along the second direction. Therefore, when a force is applied to the side portions of the sheet to fold back, the force is easily transmitted to the ends of the cleaning sheet in the second direction, making it easy to fold back the entire side portions of the sheet in the second direction. The deformation of the sheet side portions as they fold back is also propagated in the first direction by the edges of the cleaning surface extending in the first direction, allowing the entire sheet side portions to be folded back smoothly. Furthermore, when removing the cleaning sheet, a force to unfold the cleaning sheet is applied to the sheet side portions. At this time, this force is easily propagated to the entire sheet side portions in the second direction, making it easier to fold back the entire sheet side portions in the second direction. The deformation of the sheet side portions as they unfold is also propagated in the first direction by the creases created by the folds, allowing the entire sheet side portions to be unfolded smoothly. This allows the cleaning sheet to be smoothly attached to and detached from the cleaning tool, improving the operability of the cleaning sheet attachment and detachment process.

[0013] Aspect 3 of the invention relates to a cleaning sheet according to the third aspect. The cleaning sheet is attached to a cleaning tool that extends in a planar direction including a first direction and a second direction and has a cleaning surface facing a cleaning target. The side portions of the cleaning sheet in the second direction are folded back along the edges of the cleaning surface extending in the first direction, and are configured to detachably engage with the cleaning tool. The fibers of the cleaning sheet are oriented in the second direction. The cleaning sheet has fibers oriented in the second direction, making it difficult to stretch in the second direction and easy to transmit force along the second direction. Therefore, when a force is applied to the side portions of the sheet to fold back, the force is easily transmitted to the ends of the cleaning sheet in the second direction, making it easy to fold back the entire side portions of the sheet in the second direction. The deformation of the side portions of the sheet when folded back is also propagated in the first direction by the edges of the cleaning surface extending in the first direction, allowing the entire side portions of the sheet to be smoothly folded back. Furthermore, when the cleaning sheet is to be removed, a force is applied to the side portions of the sheet to unfold the cleaning sheet. At this time, the force is easily transmitted to the entire side of the sheet in the second direction, making it easier to fold back the entire side of the sheet in the second direction. The deformation of the unfolding side of the sheet is also propagated in the first direction due to the creases created by the folds, allowing the entire side of the sheet to unfold smoothly. This allows the cleaning sheet to be smoothly attached to and detached from the cleaning tool, improving the operability of attaching and detaching the cleaning sheet.

[0014] The invention according to Aspect 4 is the invention according to any one of Aspects 1 to 3, and has the following features. The cleaning sheet has protrusions protruding in the thickness direction and recesses arranged between the protrusions. The protrusions and recesses extend in the second direction and are arranged alternately in the first direction. According to this aspect, the presence of the protrusions and recesses extending in the second direction makes the cleaning sheet less likely to stretch or bend in the second direction, making it easier to transmit force along the second direction. Therefore, when a force is applied to fold back or unfold the side portions of the sheet, the force is more easily transmitted to the ends of the cleaning sheet in the second direction, making it easier to fold back or unfold the entire side portions of the sheet in the second direction, improving operability.

[0015] The invention according to Aspect 5 has the following features in the invention according to Aspect 4. According to this aspect, the convex portions and the concave portions have minute concave portions that are concave in the thickness direction and are spaced apart in the second direction. When the cleaning sheet is moved in the second direction, the convex portions and the concave portions are aligned with the second direction, so that the cleaning sheet can be moved while reducing friction with the cleaning surface. However, because the convex portions and the concave portions are aligned with the movement direction, there is a risk that dust and dirt that once hits the convex portions and the concave portions will pass through in the second direction. However, the minute concave portions can hold the dust and dirt, and the dust and dirt that was once drawn in can be continued to be held.

[0016] The invention according to aspect 6 is the invention according to either aspect 4 or aspect 5, and has the following features. The distance in the thickness direction between the apex of the convex portion and the bottom surface of the concave portion is 0.5 mm or more and 5.0 mm or less. The pitch of the convex portions is 3.0 mm or more and 10.0 mm or less. According to this aspect, the distance in the thickness direction between the apex of the convex portion and the bottom surface of the concave portion is 0.5 mm or more, and the pitch of the convex portions is 3.0 mm or more, thereby ensuring the volume of the concave portion and making it easier to retain dust, etc. in the concave portion. Furthermore, the distance in the thickness direction between the apex of the convex portion and the bottom surface of the concave portion is 5.0 mm or less, making it easier for dust, etc. to hit the fibers forming the bottom surface of the concave portion and make it easier for the fibers to retain dust, etc. Furthermore, since the pitch of the convex portions is 10.0 mm or less, dust, etc. on the wiping surface is easily drawn into one of the concave portions.

[0017] The invention according to Aspect 7 is the invention according to any one of Aspects 1 to 6, and has the following features. The cantilever bending resistance of the cleaning sheet in the second direction may be higher than the cantilever bending resistance of the cleaning sheet in the first direction, and the ratio of the cantilever bending resistance to the cantilever bending resistance of the cleaning sheet in the first direction may be 1.1 or more and 3.0 or less. According to this aspect, the cantilever bending resistance in the second direction / the cantilever bending resistance in the first direction is 1.1 or more, so that force is more easily transmitted in the second direction than in the first direction, and force is transmitted to the entire cleaning sheet in the second direction, improving operability when attaching and removing the cleaning sheet. Furthermore, the cantilever bending resistance in the second direction / the cantilever bending resistance in the first direction is 3.0 or less, so that the difference between the rigidity in the second direction and the rigidity in the first direction is not too large, and force transmissibility in both the first direction and the second direction can be achieved.

[0018] The invention according to aspect 8 is the invention according to any one of aspects 1 to 7, and has the following features. The tensile strength of the cleaning sheet in the second direction is higher than the tensile strength of the cleaning sheet in the first direction, and the ratio of the tensile strength of the cleaning sheet to the tensile strength of the cleaning sheet in the first direction is greater than 1.0 and not greater than 5.0. According to this aspect, the tensile strength in the second direction / the tensile strength in the first direction is greater than 1.0, so force is more easily transmitted in the second direction than in the first direction, and force is transmitted to the entire cleaning sheet in the second direction, improving the operability of attaching and removing the cleaning sheet. Furthermore, the tensile strength in the second direction / the tensile strength in the first direction is not too large, so force transmittance in both the first and second directions is achieved.

[0019] The invention according to Aspect 9 is the invention according to any one of Aspects 1 to 8, and has the following features. The cleaning sheet has a base layer impregnated with a chemical solution and a pair of outer layers covering both sides of the base layer in the thickness direction. The base layer contains absorbent fibers and crimped fibers. The pair of outer layers contain absorbent fibers, crimped fibers, and non-absorbent fibers. According to this aspect, the chemical solution is retained by the absorbent fibers contained in the base layer, and both sides of the base layer are covered by the outer layers. This prevents the surface that retains the chemical solution from directly contacting the object to be cleaned, thereby reducing clogging due to the surface tension of the chemical solution. The outer layer contains non-absorbent fibers, which make it difficult for the chemical solution to be retained, further reducing clogging due to the surface tension of the chemical solution. This makes it easier to move the cleaning sheet smoothly over the object to be cleaned and perform the wiping operation. In addition, crimped fibers are contained in all three layers, and the crimping of the fibers increases recovery in the thickness direction.

[0020] 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 folded before use using a plurality of sheet folds as base points. The sheet folds are arranged along the second direction and at intervals in the first direction. According to this aspect, the sheet folds are arranged along the second direction, and the creases in the sheet folds increase the bending rigidity in the second direction, making it easier to transmit force along the second direction.

[0021] Aspect 11 of the invention is the invention of aspect 9, wherein the sheet folds have the following characteristics: no folds along the first direction, but only folds along the second direction. According to this aspect, the folds make it easy for the force of folding or unfolding the sheet to propagate in the first direction. However, because only sheet folds extending in the second direction are provided, the force is easily transmitted in the second direction while being suppressed from propagating in the first direction. Therefore, the force is transmitted to the entire cleaning sheet in the second direction, making it easy to fold the entire side of the sheet in the second direction.

[0022] Aspect 12 of the invention is the same as Aspects 9 and 10 of the invention, but has the following features. The sheet folds include valley folds that form valley folds when the cleaning sheet is unfolded, and mountain folds that form mountain folds when the cleaning sheet is unfolded. The valley folds and mountain folds are provided on both sides of the center of the cleaning sheet in the first direction when the cleaning sheet is unfolded. According to this aspect, since the valley folds and mountain folds are provided on both sides of the center of the cleaning sheet in the first direction, a force transmitted in the first direction is guided to the second direction via one of the valley folds and mountain folds, and the other of the valley folds and mountain folds applies the force on one side in the opposite direction to the thickness direction, thereby transmitting the force in the planar direction. This makes it easier to transmit the overall deformation of the sheet side in the second direction to the entire cleaning sheet in the first direction.

[0023] (2) Cleaning sheet according to the embodiment The cleaning sheet 1 according to the embodiment will be described below with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same 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.

[0024] The cleaning sheet 1 is a sheet that is attached to a 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 an embodiment and the cleaning sheet 1 attached to the cleaning tool 200. The cleaning tool 200 has a cleaning surface 210 that faces the object to be cleaned. The cleaning surface 210 may be provided on a cleaning head 201. The cleaning surface 210 extends in a planar direction that includes a first direction D1 and a second direction D2. The cleaning sheet 1 comes into contact with the cleaning surface 210, and the cleaning sheet 1 cleans the object to be cleaned by the contacted cleaning surface 210. The cleaning surface 210 may be a rectangular surface.

[0025] The cleaning tool 200 may have an engagement portion 230 that detachably engages with the cleaning sheet 1 at a location other than the cleaning surface 210, such as the surface opposite the cleaning surface 210. The engagement portion 230 detachably engages with the cleaning sheet 1 folded back along an edge of the cleaning surface 210 extending in the first direction D1. The edge of the cleaning surface 210 extending in the first direction D1 is an edge of the rectangular surface in the second direction of the cleaning surface 210. The cleaning tool 200 may have a grip portion 250 that is connected to the cleaning surface 210 and gripped by a user. The length of the cleaning surface 210 in the first direction D1 may be longer than the length of the cleaning surface 210 in the second direction D2. In this embodiment, the length of the cleaning surface 210 in the first direction D1 is at least 2.0 times the length of the cleaning surface 210 in the second direction D2. In a configuration in which the length of cleaning surface 210 in first direction D1 is long in second direction D2 of cleaning 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).

[0026] The cleaning sheet 1 is a sheet-like fibrous structure that functions to clean the surface of a cleaning target, such as a floor, furniture, or home appliance, by wiping off dust and dirt therefrom. FIG. 2 is a plan view of the cleaning sheet 1. FIG. 3 is a schematic cross-sectional and perspective view of the cleaning sheet 1. FIG. 4 is a cross-sectional photograph of a cleaning sheet according to an embodiment. FIG. 5 is a plan view of a cleaning sheet according to an embodiment. 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 first side 31 and a second side 32 that extend in the planar direction. The second side 32 is the side opposite to the first side 31. In this embodiment, the shape of the first side 31 and the shape of the second side 32 are substantially the same, and both form wiping surfaces that wipe the cleaning target. A user can clean with the first surface 31 by bringing the second surface 32 into contact with the cleaning surface 210 of the cleaning tool 200, and can also clean with the second surface 32 by bringing the first surface 31 into contact with the cleaning surface 210 of the cleaning tool 200. In other words, dust and dirt on the cleaning target can be wiped off with both the first surface 31 and the second surface 32. Therefore, the description of the first surface 31 can be replaced with the description of the second surface 32, and the plan view seen from the first surface 31 side shown in FIG. 2 can be replaced with a plan view seen from the second surface 32 side.

[0027] The side portions of the cleaning sheet 1 in the second direction D2 are folded back along the edges of the cleaning surface 210 extending in the first direction D1, and are configured to releasably engage with the cleaning tool 200. The cleaning sheet 1 may have a sheet center portion R1 placed on the cleaning surface 210, and sheet side portions R2 located on both sides of the sheet center portion R1 in the second direction D2, folded back along the edges of the cleaning surface 210 extending in the first direction D1, and releasably 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 cleaning surface 210, etc., 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.

[0028] The cleaning sheet 1 of this embodiment is configured to improve the operability of attaching and detaching the cleaning sheet 1 to and from the cleaning tool 200. Next, the configuration of the cleaning sheet 1 for improving the operability of attaching and detaching the cleaning sheet 1 to and from the cleaning tool 200 will be described in detail. The modes for improving the operability of attaching and detaching the cleaning sheet 1 to and from the cleaning tool 200 can be broadly divided into first to third modes. In the first mode, the cantilever bending resistance of the cleaning sheet 1 in the second direction D2 is higher than the cantilever bending resistance of the cleaning sheet 1 in the first direction D1. When attaching the cleaning sheet 1 to the cleaning tool 200, the sheet side portion R2, which is the side portion of the cleaning sheet in the second direction, is folded back along the edge of the cleaning surface 210 extending in the first direction D1. The cleaning sheet 1 according to the first mode has a high cantilever bending resistance in the second direction D2 and is therefore easy to transmit force along the second direction D2. Therefore, when a folding force is applied to the sheet side portion R2, the force is easily transmitted to the end of the cleaning sheet 1 in the second direction D2, making it easy to fold the entire sheet side portion R2 in the second direction D2. The folding deformation of the sheet side portion R2 is also propagated in the first direction D1 by the edge of the cleaning surface 210 extending in the first direction D1, allowing the entire sheet side portion R2 to be smoothly folded back. When removing the cleaning sheet 1, a force to unfold the cleaning sheet 1 is applied to the sheet side portion R2. At this time, the force is easily transmitted to the entire sheet side portion R2 in the second direction D2, making it easy to fold the entire sheet side portion R2 in the second direction D2. The unfolding deformation of the sheet side portion R2 is also propagated in the first direction D1 by the crease formed by the fold created by folding the sheet around the edge of the cleaning surface 210 extending in the first direction D1, allowing the entire sheet side portion R2 to be smoothly unfolded. Therefore, the cleaning sheet 1 can be smoothly attached to and detached from the cleaning tool 200, improving the operability of the work of attaching and detaching the cleaning sheet 1.

[0029] The cantilever bending resistance of the cleaning sheet 1 is measured using an electric cantilever softness tester, CAN-1MCA, manufactured by Daiei Scientific Instruments Co., Ltd. First, a cleaning sheet is cut into a length of 150 mm x 25 mm to obtain a sample to be measured. The sample for measuring bending resistance in the first direction is 150 mm long in the first direction and 25 mm long in the second direction, and the sample for measuring bending resistance in the second direction is 150 mm long in the second direction and 25 mm long in the first direction. Next, the sample is placed on a test table. The sample is slid along a 45-degree inclined surface of the test table at a speed of 5 mm / sec, and the measured movement distance is taken as the cantilever bending resistance (mm).

[0030] The cantilever bending resistance in the first direction D1 may be 20 mm or more and 75 mm or less, and the cantilever bending resistance in the second direction D2 may be 50 mm or more and 115 mm or less.

[0031] In the second embodiment, the tensile strength of the cleaning sheet 1 in the second direction D2 is higher than the tensile strength of the cleaning sheet 1 in the first direction D1. The cleaning sheet 1 according to the second embodiment has a relatively high tensile strength in the second direction, is less likely to stretch in the second direction, and easily transmits force along the second direction. Therefore, when a force is applied to the side of the sheet, the force is easily transmitted to the end of the cleaning sheet in the second direction, making it easy to fold or unfold the entire side of the sheet in the second direction. This allows the cleaning sheet to be smoothly attached to and detached from a cleaning tool, improving the operability of attaching and detaching the cleaning sheet.

[0032] The tensile strength of the cleaning sheet 1 can be measured by the following method. (1) Prepare a tensile tester and set the chuck distance to 40 mm and the chuck tension speed to 100 mm / min. (2) Cut a sample to 100 mm x 25 mm (longitudinal x transverse). The sample for measuring tensile strength in the first direction is 100 mm long in the first direction x 25 mm long in the second direction, and the sample for measuring tensile strength in the second direction is 100 mm long in the second direction x 25 mm long in the first direction. (3) Place one longitudinal end of the sample in the upper chuck of the tensile tester so that it is clamped to a depth of approximately 10 mm. (4) Similarly, place the other longitudinal end of the sample in the lower chuck of the tensile tester so that it is clamped to a depth of approximately 10 mm. (5) Start the tensile test at a chuck tension speed of 100 mm / min and continue the tensile test until the sample breaks. (6) The maximum tensile strength value during the 150 mm displacement is recorded. (7) The above procedure is repeated four more times, and the average value of the maximum tensile strength values ​​measured five times is calculated. An example of the tensile tester is an autograph tensile tester model AG-1KNI manufactured by Shimadzu Corporation.

[0033] The tensile strength in the first direction may be 5N / 25mm or more and 20N / 25mm or less, and the tensile strength in the second direction may be 20N / 25mm or more and 100N / 25mm or less.

[0034] In the third embodiment, the fibers of the cleaning sheet 1 are oriented in the second direction D2. The cleaning sheet 1 of the third embodiment has fibers oriented in the second direction, making it difficult to stretch in the second direction and easy to transmit force along the second direction. Therefore, when force is applied to the side of the sheet, the force is easily transmitted to the edge of the cleaning sheet in the second direction, making it easy to fold or unfold the entire side of the sheet in the second direction. This allows the cleaning sheet to be smoothly attached to and detached from a cleaning tool, improving the operability of attaching and detaching the cleaning sheet.

[0035] The orientation direction of the fibers of the cleaning sheet 1 corresponds to the conveying direction (so-called MD direction) when the nonwoven fabric is manufactured, and the orientation of the constituent fibers of the nonwoven fabric can be confirmed by magnifying and observing the orientation using a magnifying observation means (e.g., a microscope or a scanning electron microscope).

[0036] The cleaning sheet may have any of the configurations of the first to third aspects, but preferably may have any of the configurations of the first to third aspects. The cleaning sheet of the first aspect may have any of the configurations of the second and third aspects, the cleaning sheet of the second aspect may have any of the configurations of the first and third aspects, and the cleaning sheet of the third aspect may have any of the configurations of the first and second aspects. Next, preferred configurations for any of the cleaning sheets of the first to third aspects will be described.

[0037] The length of the cleaning sheet 1 in the first direction D1 may be longer than the length of the cleaning sheet 1 in the second direction D2, and may be 1.1 or more times and 5.0 or less times the length of the cleaning sheet 1 in the second direction D2. In this embodiment, the length of the cleaning sheet 1 in the first direction D1 is 540 mm, and the length in the second direction D2 is 218 mm. The ratio of the length of the sheet side portion R2 in the first direction D1 to the length of the sheet side portion R2 in the second direction D2 may be 2.0 or more and 20.0 or less.

[0038] The cantilever bending resistance of the cleaning sheet 1 in the second direction D2 is higher than that in the first direction D1 of the cleaning sheet 1, and the ratio of the cantilever bending resistance to the cantilever bending resistance in the first direction D1 of the cleaning sheet 1 may be 1.1 or more and 3.0 or less. Because the cantilever bending resistance in the second direction D2 / the cantilever bending resistance in the first direction is 1.1 or more, force is more easily transmitted in the second direction D2 than in the first direction D1, and force is transmitted to the entire second direction D2 of the cleaning sheet 1, improving operability when attaching and removing the cleaning sheet. Furthermore, because the cantilever bending resistance in the second direction / the cantilever bending resistance in the first direction is 3.0 or less, the difference between the rigidity in the second direction D2 and the rigidity in the first direction D1 is not too large, and force transmissibility in both the first direction D1 and the second direction D2 can be achieved.

[0039] The tensile strength of the cleaning sheet 1 in the second direction D2 is higher than the tensile strength of the cleaning sheet 1 in the first direction D1, and the ratio of the tensile strength of the cleaning sheet 1 to the tensile strength of the cleaning sheet 1 in the first direction D1 may be greater than 1.0 and not greater than 5.0. According to this aspect, the tensile strength in the second direction D2 / the tensile strength in the first direction is greater than 1.0, so force is more easily transmitted in the second direction D2 than in the first direction D1, and force is transmitted to the entire second direction D2 of the cleaning sheet 1, improving the operability of attaching and removing the cleaning sheet 1. Furthermore, the tensile strength in the second direction D2 / the tensile strength in the first direction D1 is not too large, so that the difference between the tensile strength in the second direction D2 and the tensile strength in the first direction D1 is not too large, and force transmissibility in both the first direction D1 and the second direction D2 can be achieved.

[0040] The cleaning sheet 1 may be configured to include at least one fiber layer, and preferably may include multiple fiber layers. The cleaning sheet 1 may be a dry sheet or a wet sheet. The cleaning sheet 1 may have a three-layer structure, and in the case of a wet cleaning sheet 1, the middle layer of the three layers may function as a water-retaining layer that retains chemical solution, and the outer layers may be configured to form a wiping surface for wiping the object to be cleaned and to be able to release chemical solution.

[0041] The cleaning sheet 1 may have a base layer 11 impregnated with a chemical solution and a pair of outer layers 12 covering both sides of the base layer 11 in the thickness direction. The outer layer 12 may be composed of a hydrophobic nonwoven fabric or a hydrophilic nonwoven fabric. When the outer layer 12 is composed of a hydrophobic nonwoven fabric, the cleaning target can be wiped with relatively little force, and the constituent fibers are less likely to become worn even when the cleaning sheet 1 is wet, thereby achieving superior dirt removal performance. The hydrophobic nonwoven fabric constituting the outer layer 12 is not particularly limited as long as it can form the wiping surface of the cleaning sheet 1, and any hydrophobic nonwoven fabric can be used. Such a hydrophobic nonwoven fabric may be composed of only hydrophobic fibers or a nonwoven fabric composed of hydrophilic and hydrophobic fibers, as long as it has hydrophobic properties as a nonwoven fabric. The thickness and basis weight of the hydrophobic nonwoven fabric constituting the outer layer 12 are not particularly limited as long as they do not impair the effects of the present invention, and any thickness and basis weight can be used.

[0042] The base layer 11 may be formed of a hydrophilic nonwoven fabric capable of retaining the chemical solution of the cleaning sheet 1. By forming the base layer 11 from a hydrophilic nonwoven fabric, the cleaning sheet 1 can appropriately release the chemical solution retained in the base layer 11 to the object to be cleaned via the outer layer 12. The hydrophilic nonwoven fabric forming the base layer 11 is not particularly limited as long as it is capable of retaining the chemical solution, and any hydrophilic nonwoven fabric can be used. The thickness and basis weight, etc. of the hydrophilic nonwoven fabric forming the base layer 11 are not particularly limited as long as they do not impede the effects of the present invention, and any thickness, basis weight, etc. can be adopted. When the three layers of the outer layer 12 and the base layer 11 are one nonwoven fabric as in this embodiment, the basis weight of one outer layer 12 and the basis weight of the base layer 11 are, for example, 15 g / m 2 More than 20g / m 2 or less, and the basis weight of the other outer layer 12 may be 35.0 g / m 2 More than 40g / m 2 In addition, when the three layers of the outer layer 12 and the base layer 11 are made of different nonwoven fabrics, the basis weight of the outer layer 12 may be, for example, 20 g / m 2 More than 40g / m 2 The basis weight of the base layer 11 may be, for example, 35 g / m2 More than 65g / m 2 It may be the following:

[0043] The base layer 11 may contain absorbent fibers and crimped fibers. The pair of outer layers 12 may contain absorbent fibers, crimped fibers, and non-absorbent fibers. According to this embodiment, the absorbent fibers contained in the base layer 11 retain the chemical solution, and by covering both sides of the base layer with the outer layers, the surface retaining the chemical solution does not come into direct contact with the object to be cleaned, thereby reducing clogging due to the surface tension of the chemical solution. The outer layer 12 contains non-absorbent fibers, which make it difficult for the chemical solution to be retained by these fibers, further reducing clogging due to the surface tension of the chemical solution. This makes it easier to move the wiper smoothly over the object to be cleaned and perform the wiping operation. In addition, crimped fibers are contained in all three layers, and the crimping of the fibers increases recovery in the thickness direction T.

[0044] Here, absorbent fibers are fibers with a high affinity for water, such as pulp fibers and cellulose-based absorbent fibers. Non-absorbent fibers are fibers with a low affinity for water, such as polyethylene terephthalate. Crimped fibers are fibers that shrink into an Ω-shape or spiral shape when thermally processed, and have the property of becoming bulky. The outer layer 12 of this embodiment contains rayon as an absorbent fiber, polyethylene terephthalate as a non-absorbent fiber, and crimped fibers, and is impregnated with a cleaning chemical solution. The base layer 11 contains rayon and crimped fibers as absorbent fibers, but does not contain non-absorbent fibers, and is impregnated with a cleaning chemical solution. The weight ratio of fibers in the base layer 11 is 70% absorbent fiber and 30% crimped fiber, with the absorbent fiber accounting for the highest weight ratio. The weight ratio of fibers in the outer layer 12 is 30% absorbent fiber, 20% non-absorbent fiber, and 50% crimped fiber, with the weight ratio of crimped fiber being the highest.

[0045] It is preferable that the crimped fibers of the cleaning sheet 1 are not fused together at their intersections. This configuration allows each crimped fiber to easily shrink and deform, maintaining the cushioning properties of the cleaning sheet 1. The crimped fibers may also include a retaining portion that holds other fibers together. This configuration reduces fiber loss due to the presence of the retaining portion, improving the strength and rigidity of the cleaning sheet 1 and improving durability. The retaining portion may be formed by a portion formed when the crimped fibers shrink during thermal processing, wrapping around surrounding fibers such as rayon.

[0046] The cleaning sheet 1 may have protrusions 41 protruding in the thickness direction and recesses 42 arranged between the protrusions 41. The protrusions 41 and recesses 42 may extend in the second direction D2 and be arranged alternately in the first direction D1. The presence of the protrusions 41 and recesses 42 extending in the second direction D2 makes the cleaning sheet 1 less likely to stretch or bend in the second direction D2, making it easier to transmit force along the second direction D2. Therefore, when a force to fold back or unfold the sheet side portion R2 is applied, the force is more easily transmitted to the end of the cleaning sheet 1 in the second direction D2, making it easier to fold back the entire sheet side portion in the second direction, improving operability.

[0047] The protrusions 41 and the recesses 42 may be provided on at least one of the first surface 31 and the second surface 32 of the cleaning sheet 1; in this embodiment, they are provided on both the first surface 31 and the second surface 32. The protrusions 41 and the recesses 42 may be formed only on the outer layer 12, or may be formed on both the base material layer 11 and the outer layer 12. In the cleaning sheet 1 of this embodiment, the base material layer 11 has a substantially uniform thickness, and the protrusions 41 and the recesses 42 are formed only on the outer layer 12. The protrusions 41 and the recesses 42 may be provided over the entire area of ​​the cleaning sheet 1 in the second direction D2. The boundary between the protrusions 41 and the recesses 42 may be the midpoint in the thickness direction T between the apex of the protrusion 41 and the bottom of the recess 42. The length of the protrusions 41 in the first direction D1 may be the same as or different from the length of the recesses 42 in the first direction D1.

[0048] The distance T40 in the thickness direction between the apex of the convex portion 41 and the bottom surface of the concave portion 42 may be 0.5 mm or more and 5.0 mm or less. The pitch P41 of the convex portions 41 may be 3.0 mm or more and 10.0 mm or less. The pitch P42 of the concave portions 42 may be 3.0 mm or more and 10.0 mm or less. The pitch is the distance between the centers of the convex portions (concave portions) in the first direction D1. 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 setting the distance T40 in the thickness direction between the apex of the convex portion 41 and the bottom surface of the concave portion 42 to be 0.5 mm or more and the pitch P41 of the convex portions 41 to be 3.0 mm or more, the volume of the concave portions 42 is ensured, and dust and the like can be easily retained in the concave portions 42. Furthermore, since the distance T40 in the thickness direction between the apex of the convex portion 41 and the bottom surface of the concave portion 42 is 5.0 mm or less, dust and the like can easily come into contact with the fibers forming the bottom surface of the concave portion, making it easier for the fibers to hold the dust and dirt. Furthermore, since the pitch of the convex portions is 10.0 mm or less, dust and the like on the wiping surface can easily be drawn into one of the concave portions.

[0049] The protrusions 41 and the recesses 42 may have micro recesses 43 recessed in the thickness direction T and spaced apart in the second direction D2. The micro recesses 43 may be recessed from the apex of the protrusions 41 in the protrusions 41, and may be recessed from the bottom of the recesses 42 in the recesses 42. The micro recesses 43 may penetrate the cleaning sheet 1 in the thickness direction T. The micro recesses 43 may be provided in the protrusions 41, in the recesses 42, or in both the protrusions 41 and the recesses 42. The micro recesses 43 may have a first micro recess 431 provided in the protrusions 41 and a second micro recess 432 provided in the recesses 42. The length T431 of the first micro recess 431 penetrating the cleaning sheet 1 in the thickness direction T corresponds to the thickness of the cleaning sheet 1 at the protrusions 41. In this embodiment, the length T431 of the first micro recess 431 in the thickness direction T is 1.3 mm to 1.5 mm. The length T432 of the second fine recesses 432 penetrating the cleaning sheet 1 in the thickness direction T corresponds to the thickness of the cleaning sheet 1 at the recesses 42. In this embodiment, the length T432 of the second fine recesses 432 in the thickness direction T is 0.3 mm to 0.45 mm. Because the protrusions 41 and recesses 42 are aligned with the second direction D2, the cleaning sheet 1 can move with reduced friction with the cleaning surface when moved in the second direction D2. However, because the protrusions 41 and recesses 42 are aligned with the movement direction, dust and debris that hit the protrusions 41 and recesses 42 may pass through in the second direction D2. However, the fine recesses 43 can retain the dust and debris, allowing the dust and debris to continue to be retained once drawn in. Note that the fine recesses 43 only need to be spaced apart at least in the second direction D2, and as shown in FIG. 3, they only need to be spaced apart in the first direction D1 as well. The length of the minute recesses 43 in the thickness direction T may be, for example, 0.5 mm or more and 2.0 mm or less.

[0050] The method for manufacturing the cleaning sheet 1 configured in this manner is not particularly limited, and conventional methods for manufacturing cleaning sheets 1 can be appropriately adopted. The method for manufacturing the cleaning sheet 1 of this embodiment may include at least steps 1, 2, and 3. In step 1, a fiber layer is formed by entangling fibers using a nozzle extending in a stripe shape. In step 2, the fiber layer is placed on a mesh belt and a high-pressure water stream is applied. At this time, fibers present at the intersections of the mesh are pressed against the surrounding area by the water stream, and openings that become voids in the fibers are formed at positions that overlap with the intersections of the mesh. These openings form fine recesses 43. In step 3, heat is applied to the fiber layer, and convex portions 41 and concave portions 42 are formed by thermal contraction of the crimped fibers.

[0051] The cleaning sheet 1 may be folded before use and stored in the container, or may be stored unfolded. The cleaning sheet 1 of this embodiment is folded around multiple sheet folds before use. FIG. 6 is a diagram showing an example of a folding mode of the cleaning sheet 1. FIG. 6(A) shows a state in which the cleaning sheet 1 is not folded along any of the sheet folds, and for convenience of explanation, the sheet folds are shown. In the front view shown in FIG. 6, the sheet folds may include a valley fold FL1 that folds the cleaning sheet into a valley fold and a mountain fold FL2 that folds the cleaning sheet 1 into a mountain fold. The valley fold FL1 forms a valley fold crease when the cleaning sheet is unfolded, and the mountain fold FL2 forms a mountain fold crease when the cleaning sheet is unfolded.

[0052] The cleaning sheet 1 is folded in two from the unfolded state shown in Fig. 6(A) around a valley fold FL1 located in the center in the first direction D1. Fig. 6(B) shows the state folded in two. In this folded state, one end of the cleaning sheet 1 in the first direction D1 (the end on the valley fold FL1 side located in the center in the first direction) is folded around a mountain fold FL2, and the other end of the cleaning sheet 1 in the first direction D1 is folded around the valley fold FL1. Fig. 6(C) shows the state in which both end portions of the cleaning sheet 1 in the first direction D1 are folded.

[0053] The sheet folds may be arranged along the second direction D2 and at intervals in the first direction D1. The sheet folds are arranged along the second direction D2, and the creases of the sheet folds increase the bending rigidity in the second direction D2, making it easier to transmit force along the second direction D2.

[0054] Furthermore, the sheet folds may not include folds along the first direction D1, but may only include folds along the second direction D2. When the sheet folds along the first direction D1 when folded before use, the force of folding or unfolding the cleaning sheet 1 is likely to propagate in the first direction D1 due to the creases extending in the first direction D1. However, since only sheet folds extending in the second direction D2 are provided, the force is easily transmitted in the second direction while being suppressed from propagating in the first direction. This makes it easier to transmit the force to the entire cleaning sheet 1 in the second direction D2, and to fold back the entire sheet side portion R2 in the second direction. Note that the folds along the first direction D1 include not only folds parallel to the first direction but also folds extending in a direction inclined at an angle of 10 degrees or less relative to the first direction. Similarly, the folds along the second direction D2 include not only folds parallel to the second direction but also folds extending in a direction inclined at an angle of 10 degrees or less relative to the second direction.

[0055] The valley fold FL1 and the mountain fold FL2 may be provided on both sides of the center of the cleaning sheet 1 in the first direction D1 when it is unfolded. Because the valley fold FL1 and the mountain fold FL2 are provided on both sides of the center of the cleaning sheet 1 in the first direction D1, the force transmitted in the first direction D1 is guided to the second direction via one of the valley fold or the mountain fold, and the other of the valley fold or the mountain fold acts on the force on one side in the opposite direction to the thickness direction, transmitting the force in the planar direction. This makes it easier to transmit the overall deformation of the sheet side in the second direction to the entire cleaning sheet in the first direction.

[0056] 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]

[0057] 1: Cleaning sheet R1: Center of seat R2: Seat side 200: Cleaning tools 210:Cleaning surface D1: 1st direction D2 :Second direction T: Thickness direction

Claims

1. A cleaning sheet to be attached to a cleaning tool that extends in a planar direction including a first direction and a second direction and has a cleaning surface facing an object to be cleaned, a side portion of the cleaning sheet in the second direction is folded back along an edge of the cleaning surface extending in the first direction and configured to be removably engaged with the cleaning tool, The cleaning sheet has a cantilever bending resistance in the second direction that is higher than a cantilever bending resistance in the first direction.

2. A cleaning sheet to be attached to a cleaning tool that extends in a planar direction including a first direction and a second direction and has a cleaning surface facing an object to be cleaned, a side portion of the cleaning sheet in the second direction is folded back along an edge of the cleaning surface extending in the first direction and configured to be removably engaged with the cleaning tool, The cleaning sheet has a higher tensile strength in the second direction than the tensile strength in the first direction.

3. A cleaning sheet to be attached to a cleaning tool that extends in a planar direction including a first direction and a second direction and has a cleaning surface facing an object to be cleaned, a side portion of the cleaning sheet in the second direction is folded back along an edge of the cleaning surface extending in the first direction and configured to be removably engaged with the cleaning tool, The cleaning sheet has fibers oriented in the second direction.

4. the cleaning sheet has protrusions protruding in a thickness direction and recesses disposed between the protrusions, The cleaning sheet according to claim 1 , wherein the protrusions and the recesses extend in the second direction and are alternately arranged in the first direction.

5. The cleaning sheet according to claim 4 , wherein the protrusions and the recesses are provided with minute recesses recessed in the thickness direction at intervals in the second direction.

6. a distance in the thickness direction between the apex of the convex portion and the bottom surface of the concave portion is 0.5 mm or more and 5.0 mm or less; The cleaning sheet according to claim 4 , wherein the pitch of the protrusions is equal to or greater than 3.0 mm and equal to or less than 10.0 mm.

7. 4. The cleaning sheet according to claim 1, wherein a cantilever bending resistance of the cleaning sheet in the second direction is higher than a cantilever bending resistance of the cleaning sheet in the first direction, and a ratio of the cantilever bending resistance of the cleaning sheet to the cantilever bending resistance of the cleaning sheet in the first direction is 1.1 or more and 3.0 or less.

8. 4. The cleaning sheet according to claim 1, wherein the tensile strength of the cleaning sheet in the second direction is higher than the tensile strength of the cleaning sheet in the first direction, and a ratio of the tensile strength of the cleaning sheet in the second direction to the tensile strength of the cleaning sheet in the first direction is greater than 1.0 and not greater than 5.

0.

9. The cleaning sheet has a base layer impregnated with a chemical solution and a pair of outer layers covering both sides of the base layer in a thickness direction, The substrate layer includes absorbent fibers and crimped fibers, The cleaning sheet according to claim 1 , wherein the pair of outer layers comprises absorbent fibers, crimped fibers, and non-absorbent fibers.

10. the cleaning sheet is folded along a plurality of sheet folds before use; The cleaning sheet according to claim 1 , wherein a plurality of the sheet folds are provided along the second direction and spaced apart in the first direction.

11. The cleaning sheet according to claim 10 , wherein the sheet fold does not include folds along the first direction, and only includes folds along the second direction.

12. the sheet folds include valley folds that form valley folds when the cleaning sheet is in an unfolded state, and mountain folds that form mountain folds when the cleaning sheet is in the unfolded state, The cleaning sheet according to claim 10 , wherein the valley fold and the mountain fold are provided on both sides of the center of the cleaning sheet in the first direction in the unfolded state.

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