JP7359676B2 - wet wiping sheet - Google Patents

Description

The present invention relates to a wet wiping sheet.

BACKGROUND ART Fiber aggregates made by fusing or entangling cellulose fibers or fibers made from thermoplastic resins are used for various purposes. The present applicant has a first surface and a second surface opposite to the first surface, and is made of a fiber aggregate of at least two types of fibers having different fiber diameters, and the wiping liquid is applied to at least the second surface. A wet wiping sheet supported by a fiber aggregate on the surface side was proposed (Patent Document 1). In this sheet, the fibers are intertwined, and the proportion of fibers with small diameters is higher on the first side than on the second side, and the proportion of fibers with larger diameters is higher on the first side than on the first side. The capillary pressure is higher on the second surface side, and the capillary pressure on the first surface side is higher than that on the second surface side.

Furthermore, Patent Document 2 discloses that an ultrafine fiber layer containing 50% by weight or more of splittable conjugate fibers is arranged on at least one side of a hydrophilic fiber layer containing 50% by weight or more of hydrophilic fibers, and three-dimensional entanglement is achieved. A cleaning nonwoven fabric made of a composite nonwoven fabric that is integrated by bonding is disclosed. The same document also discloses that this nonwoven fabric for cleaning has an average fiber length of less than 20 mm of the fibers constituting the hydrophilic fiber layer, and an average fiber length of 30 to 100 mm of the fibers constituting the ultrafine fiber layer. ing.

Patent Document 3 describes a first direction and a second direction intersecting the first direction, a surface layer mainly composed of hygroscopic long fibers with an average fiber diameter of 10 μm or less, and a surface layer composed of short fibers with an average fiber diameter of more than 10 μm. A wipe sheet is disclosed having a backing layer primarily configured. In this wiping sheet, in the surface layer, the long fibers draw arcs irregularly and spread uniformly in a mesh shape, and in the back layer, a plurality of openings aligned in the first direction are formed, and the long fibers are arranged in the first direction. The same document also discloses that it straddles at least a portion of the aperture.

JP2018-89348A Japanese Patent Application Publication No. 2001-190469 International Publication No. 2016/132790 pamphlet

The wiping sheet described in Patent Document 1 can be wiped lightly to remove dirt, and needs to be replaced infrequently even if the wiping area is large, but it has excellent liquid release properties, operability during use, and dirt collection properties. There was room for further improvement in terms of both. Further, the nonwoven fabrics and sheets of Patent Documents 2 and 3 do not have a high level of liquid release properties, operability during use, and dirt collection properties.

Therefore, an object of the present invention is to provide a wet wiping sheet that has a high level of sustained liquid release properties, operability during use, and dirt collection properties.

The present invention provides a first fiber layer containing hydrophilic fibers, a second fiber layer adjacent to the first fiber layer and containing large diameter fibers having a fiber diameter of 30 μm or more, and a first fiber layer in the second fiber layer. a third fiber layer adjacent to the side on which no layer is arranged and containing small fibers with a fiber diameter of 2 μm or less,
The present invention provides a wet wiping sheet having a basis weight of 110 g/m ² or more and carrying a cleaning liquid.

According to the present invention, a wet wiping sheet is provided that has a high level of sustained liquid release properties, operability during use, and dirt collection properties.

FIG. 1 is a schematic perspective view showing an embodiment of the wet wiping sheet of the present invention. FIG. 2 is a schematic cross-sectional view of the wet wiping sheet shown in FIG. 1 taken along the II plane. FIG. 3 is an image of a cross section along the thickness direction of the wet wiping sheet observed with a scanning electron microscope. FIG. 4(a) is another image of the cross section along the thickness direction of the wet wiping sheet observed with a scanning electron microscope, and FIG. 4(b) is an observation of the first surface of the wet wiping sheet with a scanning electron microscope. It is a statue. FIG. 5 is a schematic perspective view showing another embodiment of the wet wiping sheet of the present invention. FIG. 6(a) is an embodiment of a schematic cross-sectional view taken along the II-II plane of the wet wiping sheet shown in FIG. This is an embodiment. FIG. 7 is a schematic diagram showing an embodiment of a manufacturing apparatus suitably used for manufacturing the wet wiping sheet of the present invention. FIG. 8 is a schematic diagram showing another embodiment of a manufacturing apparatus suitably used for manufacturing the wet wiping sheet of the present invention. FIG. 9(a) is a graph showing the relationship between the amount of cleaning liquid retained and the amount released when the wet wiping sheets of the example and comparative example are used, and FIG. It is a graph which shows the relationship between the basis weight of a 3rd fiber layer, and the use efficiency of a cleaning liquid when the wet wiping sheet of 2 is used. FIG. 10(a) is a graph showing the relationship between the amount of cleaning liquid retained and the amount released when the wet wiping sheet of the example is used, and FIG. It is a graph showing the usage efficiency of cleaning liquid when using a sheet. FIG. 11 is a graph showing resistance values when wet wiping sheets of Examples and Comparative Examples are used. FIG. 12 is a photograph showing the state of the surface to be cleaned and the state of the sheet after wiping using the wet wiping sheets of Examples and Comparative Examples.

Hereinafter, the wet wiping sheet of the present invention will be explained based on its preferred embodiment. In the present invention, "wiping" includes both cleaning and wiping, and includes, for example, cleaning floors, walls, ceilings, pillars, etc. of buildings, cleaning fittings and fixtures, wiping articles, and wiping bodies. This includes cleaning of equipment related to the body, etc. Furthermore, in the present invention, the term "wet type" refers to one in which a cleaning liquid is supported on the fiber aggregates constituting the sheet.

The wet wiping sheet of the present invention includes a fiber assembly including three fiber layers. Specifically, the wet wiping sheet includes a first fiber layer containing hydrophilic fibers and a second fiber layer containing large diameter fibers preferably having a fiber diameter of 30 μm or more (hereinafter, these fibers are also simply referred to as "large diameter fibers"). It is provided with two fiber layers and a third fiber layer containing thin fibers having a fiber diameter of preferably 2 μm or less (hereinafter, these fibers are also simply referred to as "thin fibers"). These fibers are integrated by at least one of fusing and entangling to form the fiber aggregate. The wet wiping sheet may be composed only of fiber aggregates, or may include other sheet materials, other members, or both in addition to fiber aggregates.

1 to 4 show an embodiment of the fiber aggregate included in the wet wiping sheet of the present invention. A wet wiping sheet 1 (hereinafter also simply referred to as "wiping sheet 1") shown in FIG. 1 has a substantially rectangular shape when viewed from above. As shown in the figure, the fiber aggregate 1A in the wiping sheet 1 includes hydrophilic fibers 11, large diameter fibers 12, and small diameter fibers 13. The wiping sheet 1 also has a first surface 1F and a second surface 1R located on the opposite side of the first surface 1F. The first surface 1F is a wiping surface that is used in contact with the surface to be cleaned when the wiping sheet 1 is used.

As shown in FIGS. 1 to 3, the wiping sheet 1 includes a first fiber layer L1 containing hydrophilic fibers 11, and a second fiber layer L1 containing large diameter fibers 12 and disposed adjacent to the first fiber layer L1. It has a layer L2 and a third fiber layer L3 that includes small diameter fibers 13 and is disposed adjacent to the side of the second fiber layer L2 on which the first fiber layer L1 is not disposed. These fiber layers L1, L2, and L3 together constitute a fiber assembly 1A. Each of the fiber layers L1, L2, and L3 in this embodiment is arranged over the entire area of the wiping sheet 1 in a plan view.

As shown in FIG. 1, the wiping sheet 1 has other fiber layers on the first surface 1F, which is the surface on which the first fiber layer L1 and the second fiber layer L2 of the third fiber layer L3 are not arranged. is not arranged. Similarly, no other fiber layer is arranged on the second surface 1R, which is the surface of the first fiber layer L1 on which the second fiber layer L2 and the third fiber layer L3 are not arranged. Therefore, the small diameter fibers 13 mainly exist on the first surface 1F, and the hydrophilic fibers 11 mainly exist on the second surface 1R. "Mainly present" means that when the wiping sheet 1 is viewed in a longitudinal cross-section along the thickness direction Z, the proportion of fibers present is highest in the above-mentioned plane.

The fiber layers L1, L2, L3 constituting the wiping sheet 1 may exist with clear boundaries between the fiber layers, as shown in FIGS. 1 and 2, or as shown in FIG. The boundaries between the fiber layers may be unclear. In either case, when the wiping sheet 1 is viewed along the thickness direction Z, the proportion of constituent fibers in each fiber layer changes stepwise, continuously, or in a combination thereof. is preferred.

When the boundary surface between each fiber layer is unclear, it is also preferable that the fibers constituting one fiber layer cross the boundary surface of the adjacent layer and invade the other fiber layer. With this structure, the supported cleaning liquid can be easily supplied to the surface to be cleaned through each fiber layer, resulting in improved sustained liquid release and dirt collection. Become something.

As a specific example of the above-mentioned aspect, as shown in FIGS. 2 and 3, the hydrophilic fibers 11 cross the interface between the first fiber layer L1 and the second fiber layer L2 and invade the second fiber layer L2 side. As shown in FIG. 4(a), the large diameter fibers 12 cross the boundary between the second fiber layer L2 and the third fiber layer L3 and invade the third fiber layer L3 side. , and combinations thereof. Note that the hydrophilic fibers 11 constituting the first fiber layer L1 may have penetrated further into the third fiber layer L3 side beyond the second fiber layer L2, or the small diameter fibers 13 constituting the third fiber layer L3 may have entered the third fiber layer L3 side beyond the second fiber layer L2. This does not prevent fibers that have penetrated beyond the second fiber layer L2 into the first fiber layer L1 side or that have penetrated into other fiber layers to be exposed on the outer surface of the sheet.

In particular, in the wiping sheet 1, as shown in FIGS. 4(a) and 4(b), the large diameter fibers 12 cross the boundary between the second fiber layer L2 and the third fiber layer L3 to the third fiber layer L3 side. and the surface of the third fiber layer L3 on the side where the first fiber layer L1 and the second fiber layer L2 are not arranged, that is, the side of the wiping sheet 1 where the third fiber layer L3 is arranged. It is preferable that at least the tips of the small-diameter fibers 13 and the large-diameter fibers 12 are both present on the first surface 1F. With this configuration, the highly rigid large-diameter fibers 12 scrape off dirt adhering to the surface to be cleaned and lift the dirt, and the third fiber layer L3 made of small-diameter fibers is dense and The structure has a low porosity and can efficiently collect and retain dirt. As a result, the ability to collect dirt is further improved.

From the viewpoint of exhibiting sufficient scraping performance for dirt existing on the surface to be cleaned, the number of large diameter fibers 12 present on the first surface 1F, which is the surface of the third fiber layer L3 constituting the wiping sheet 1, is as follows. , preferably 400 lines/cm ² or more, more preferably 500 lines/cm ² or more, and preferably 3200 lines/cm ² or less, still more preferably 3000 lines/cm ² or less. The number of large-diameter fibers 12 existing on the first surface 1F is calculated by dividing the total mass (g/cm ² ) per unit area on the first surface 1F of the wiping sheet 1 into the mass of one large-diameter fiber 12. (g).

The basis weight of the fiber aggregate 1A constituting the wiping sheet is preferably 110 g/m ² or more, more preferably 115 g/m ² or more, even more preferably 120 g/m ^{2 or} more in the dry state of the fiber aggregate, Further, it is preferably 360 g/m ² or less, more preferably 355 g/m ² or less, even more preferably 350 g/m ² or less. By having such a structure, the amount of cleaning liquid supported can be increased, and it becomes possible to have liquid release properties, operability during use, and dirt collection properties. In addition to this, there is also the advantage that the wiping sheet can exhibit strength that can withstand actual use. A dry state means that the amount of water contained in the fiber aggregate is 3% by mass or less. When measuring the basis weight of the wiping sheet carrying the cleaning liquid, the carried moisture may be removed using a known dryer, centrifugal separator, etc. until the above-mentioned moisture content is reached.

The basis weight of the first fiber layer L1 constituting the wiping sheet is preferably 50 g/m ² or more, more preferably 55 g/m ² or more, even more preferably 60 g/m ² or more in the dry state of the fiber aggregate. Moreover, it is preferably 160 g/m ² or less, more preferably 155 g/m ² or less, even more preferably 150 g/m ² or less. With such a configuration, the retention and sustained release properties of the cleaning liquid are further improved.

The basis weight of the second fiber layer L2 constituting the wiping sheet is preferably 35 g/m ² or more, more preferably 40 g/m ² or more, even more preferably 45 g/m ² or more in the dry state of the fiber aggregate. Moreover, it is preferably 115 g/m ² or less, more preferably 110 g/m ² or less, still more preferably 105 g/m ² or less. With such a configuration, the ability to scrape off dirt due to the high rigidity of the large-diameter fibers is increased, and the ability to collect dirt is further improved.

The basis weight of the third fiber layer L3 constituting the wiping sheet is preferably 20 g/m ² or more, more preferably 22 g/m ² or more, even more preferably 25 g/m ² or more in the dry state of the fiber aggregate. Moreover, it is preferably 50 g/m ² or less, more preferably 48 g/m ² or less, even more preferably 45 g/m ² or less. With such a configuration, the aggregate of small-diameter fibers has a structure with a low porosity, so that dirt can be efficiently collected and retained, and the dirt-collecting performance is further improved.

Examples of the hydrophilic fibers 11 include natural cellulose fibers such as pulp and cotton, regenerated cellulose fibers such as rayon and cupra, cellulose fibers such as purified cellulose fibers such as lyocell, polyethylene (PE), polypropylene (PP), etc. polyolefin fibers, polyester fibers such as polyethylene terephthalate (PET), PE and PET, mixed fibers of polyolefin and polyester such as PP and PET, polyamide fibers such as nylon 6 and nylon 66, vinyl fibers such as polyvinyl chloride and polystyrene. Fibers, acrylic fibers such as polyacrylonitrile, synthetic fibers such as fluorocarbon resins such as polyperfluoroethylene, etc., which have been subjected to hydrophilic treatment, may be used, and among these, pulp and rayon are preferably used. These can be used alone or in combination of two or more. Hydrophilic fiber refers to a fiber whose contact angle between the fiber surface and water is less than 90 degrees when a droplet of pure water is dropped onto the fiber in an environment of 25°C. The contact angle can be measured, for example, according to the method described in JP-A-2015-142721.

From the viewpoint of further improving the retention and sustained release properties of the cleaning liquid, the fiber diameter D1 of the hydrophilic fibers 11 is preferably smaller than the fiber diameter D2 of the large diameter fibers 12. In detail, the fiber diameter D1 of the hydrophilic fiber 11 is preferably 5 μm or more, more preferably 8 μm or more, and preferably 53 μm or less, and even more preferably 50 μm or less. The fiber diameter D1 of the hydrophilic fiber 11 can be determined, for example, by measuring the longest length in a fiber cross section perpendicular to the fiber length direction using a scanning electron microscope or the like. Such hydrophilic fibers 11 can be obtained, for example, by mechanically defibrating pulp paperboard using a hammer mill or the like, and the fibers obtained by this method are generally short fibers.

Examples of the large-diameter fibers 12 include the above-mentioned synthetic fibers, eccentric core-sheath type composite fibers or side-by-side type composite fibers containing two types of thermoplastic resins with different shrinkage rates. Therefore, composite fibers can be preferably used. Constituent components of the composite fiber include polyesters such as PE, PP, PET, co-PET, and polybutylene terephthalate (PBT), polyamides, and combinations thereof, preferably composite fibers containing two or more types of polyesters. It is a fiber. Other examples include those described in JP-A-9-296325 and the like. An example of two types of thermoplastic resins having different shrinkage rates is a combination of ethylene-propylene random copolymer and polypropylene.

From the viewpoint of both improving the feeling of use when using the wiping sheet and improving the ability to scrape off dirt, the fiber diameter D2 of the large diameter fibers 12 is preferably 30 μm or more, more preferably 35 μm or more, and preferably is 105 μm or less, more preferably 100 μm or less. The fiber diameter D2 of the large diameter fiber 12 can be measured, for example, by the method described above. Such large diameter fibers 12 can be obtained by, for example, cutting continuous tow fibers into a predetermined length with a rotary staple cutter, and the fibers obtained by this method are generally short fibers. be.

Examples of the small-diameter fibers 13 include the synthetic fibers mentioned above, and at least one of polyolefin fibers and polyester fibers is particularly preferably used.

From the viewpoint of further improving the dirt collection ability, the fiber diameter D3 of the small diameter fibers 13 is preferably 2 μm or less, more preferably 1.8 μm or less, and realistically 0.1 μm or more. The fiber diameter D3 of the small diameter fiber 13 can be measured, for example, by the method described above. Such small-diameter fibers 13 can be obtained, for example, by a method such as a melt-blowing method or an electrospinning method, and the fibers obtained by this method are generally long fibers.

From the viewpoint of achieving both reduction in frictional resistance and liquid retention, the ratio (D2/D1) of the fiber diameter D2 of the large diameter fibers 12 to the fiber diameter D1 of the hydrophilic fibers 11 is preferably 1.0 or more, more preferably is 1.2 or more, preferably 12 or less, more preferably 10 or less. In addition, from the viewpoint of easily drawing the cleaning liquid present in the first fiber layer L1 into the third fiber layer side by capillary force and increasing the usage efficiency of the supported cleaning liquid, small-diameter fibers with respect to the fiber diameter D1 of the hydrophilic fibers 11 are added. The ratio (D3/D1) of the fiber diameter D3 of No. 13 is preferably 0.008 or more, more preferably 0.010 or more, and preferably 0.08 or less, still more preferably 0.06 or less.

As described above, the wiping sheet 1 is of a wet type in which a cleaning liquid mainly composed of water is carried on the fiber aggregate, and preferably the cleaning liquid is carried on at least the first fiber layer L1. The content of water contained in the cleaning solution is preferably 80.0% by mass or more, more preferably 90.0% by mass or more, and 100% by mass or less based on the total mass of the cleaning solution. The content is preferably 99.0% by mass or less, and more preferably 99.0% by mass or less.

As the cleaning liquid supported on the wiping sheet, those having a general composition used for wet wiping sheets can be used, such as water alone or an aqueous solution containing additives. Examples of additives used in the cleaning liquid include at least one selected from the group consisting of surfactants, disinfectants, perfumes, fragrances, deodorants, pH adjusters, alcohols, brighteners, and thickeners.

The wiping sheet having the above configuration has a predetermined basis weight as a whole and has the first fiber layer L1 containing the hydrophilic fibers 11, so it can hold a large amount of cleaning liquid, and as a result, , it is possible to maintain a moist state for a long time when using the wiping sheet. Furthermore, the large-diameter fibers 12 included in the second fiber layer L2 microscopically form areas in the sheet surface direction that are easy to rebound and areas that are difficult to rebound against the pressing force generated when the sheet is pressed against the surface to be cleaned. Therefore, the contact area between the wiping sheet and the surface to be cleaned can be reduced. As a result, the frictional resistance between the wiping sheet and the surface to be cleaned can be reduced, and operability during use can be improved.

Furthermore, since the third fiber layer L3 including the small-diameter fibers 13 has a higher capillary force than other fiber layers, it becomes easier to draw the cleaning liquid held in the first fiber layer L1 toward the third fiber layer L3. As a result, a sufficient amount of cleaning liquid to remove dirt can be continuously and sustainably supplied to the surface to be cleaned, resulting in excellent sustained release of the liquid. In addition, by wiping the third fiber layer L3, which has a dense and low porosity structure, in contact with the surface to be cleaned, it is possible to improve the dirt collection and retention performance. Collectability is improved. In addition, the sheet as a whole has a predetermined basis weight and has three fiber layers with different fiber compositions, which reduces peeling and fraying of the constituent fibers and provides sufficient strength when using the wiping sheet. It also has the advantage of being able to be expressed.

In particular, according to a preferred embodiment of the present invention, both the large-diameter fibers 12 and the small-diameter fibers 13 are exposed on the first surface 1F, which is the wiping surface, so that the large-diameter fibers 12 with high rigidity are used for cleaning. While scraping off the dirt existing on the target surface, the third fiber layer L3 can collect and retain the dirt, which improves the dirt collection performance, especially the collection performance of particulate dirt such as dust and sand dust. will further improve. Additionally, compared to the case where only the small-diameter fibers contact the surface to be cleaned, the frictional resistance between the wiping sheet and the surface to be cleaned can be further reduced, further improving operability during use. can.

Another embodiment of the wiping sheet 1 is shown in FIG. 5 and FIGS. 6(a) and (b). The embodiment to be described below will be described with a focus on points that are different from the embodiments described above, and the description of the embodiments described above applies as appropriate to points that are not particularly described. Points similar to those in the embodiment described above are designated by the same reference numerals, and description thereof will be omitted.

In the embodiments shown in FIGS. 5 and 6(a) and (b), the arrangement form of the second fiber layer L2 existing between the first fiber layer L1 and the third fiber layer L3 is different. Specifically, as shown in FIGS. 5 and 6(a) and (b), in the sheet surface direction, the region where the second fiber layer L2 exists between the first fiber layer L1 and the third fiber layer L3 R1 (hereinafter also referred to as "existence region R1") and region R2 (hereinafter referred to as "non-existence region R1") where the second fiber layer L2 does not exist between the first fiber layer L1 and the third fiber layer L3. It is preferable that a region (also referred to as "region R2") is formed. A plurality of non-existing regions R2 shown in the figure are formed as belt-shaped regions in which existing regions R1 and non-existing regions R2 are alternately formed so as to extend in one direction. Alternatively, the non-existing region R2 may be formed in a dotted manner in the sheet surface direction. As shown in FIG. 5, the first fiber layer L1 and the third fiber layer L3 are each arranged throughout the sheet surface direction.

In particular, in the non-existing region R2, the fibers constituting the first fiber layer L1 such as the hydrophilic fibers 11 and the fibers constituting the third fiber layer L3 such as the small diameter fibers 13 are directly fused or intertwined. It is also preferable to be there. In the embodiment shown in FIGS. 5 and 6(a) and (b), in the non-existing region R2, the hydrophilic fibers 11 forming the first fiber layer L1 and the small diameter fibers 13 forming the third fiber layer L3 and are directly fused or intertwined. With this configuration, in the presence region R1, it is possible to improve both operability during use and dirt collection performance. In addition, since the cleaning liquid held in the first fiber layer L1 can be directly drawn into the third fiber layer L3 side, the cleaning liquid can be continuously and sustainably supplied to the surface to be cleaned, and the sustained release of the liquid can be further improved. Excellent. Furthermore, since the usage efficiency of the supported cleaning liquid can be further increased, it becomes possible to wipe a wider area with one wiping sheet.

From the viewpoint of improving the ability to scrape off dirt and the ability to remove entanglements, and further enhance the ability to collect dirt, the large-diameter fibers 12 included in the second fiber layer L2 are as shown in FIGS. As shown in 6(b), crimped fibers are preferable, and it is also preferable that the large diameter fibers 12 are exposed on the first surface 1F side. A crimped fiber is a fiber whose crimps have a spiral shape, a zigzag shape, a U-shape, or a combination thereof. When the large diameter fibers 12 are crimped fibers, the large diameter fibers 12 may be the above-mentioned composite fibers or fibers that can develop a spiral crimp by applying heat (hereinafter also referred to as latent crimped fibers). ) can be preferably used. Since the large diameter fibers 12 are crimped fibers, when the wiping sheet 1 is pressed against the surface to be cleaned, the second fiber layer L2 plays a role like a spring, so that the large diameter fibers 12 are held by the first fiber layer L1. There is also an advantage that the cleaning liquid can be more easily supplied to the third fiber layer L3 side, and the liquid utilization efficiency and liquid sustained release properties are further improved.

When the large diameter fibers 12 are crimped fibers, the number of crimps in the crimped fibers is preferably 1 or more, more preferably 2 or more, from the viewpoint of further improving dirt collection performance. The upper limit is preferably 10 or less, more preferably 8 or less. The number of crimp of the crimped fiber can be measured according to the method described in JIS L 1015.

As the constituent components of the large-diameter fiber 12, synthetic fibers containing the above-mentioned components, eccentric core-sheath type or side-by-side type composite fibers are preferably used, but from the viewpoint of further improving the sustained release property of the liquid, The large diameter fiber 12 is preferably a composite fiber of PET and co-PET or a composite fiber of PET and PE, and more preferably a composite fiber of PET and PE. In the case of an eccentric core-sheath type composite fiber, it is also preferable to use PET as the core and co-PET or PE as the sheath. In particular, composite fibers made of such components have the advantage of crimping the large-diameter fibers 12 to scrape or entangle dirt from the surface to be cleaned, thereby further improving dirt collection performance. It is advantageous.

As long as the effects of the present invention are achieved, the first fiber layer L1 constituting the wiping sheet 1 may be composed only of the hydrophilic fibers 11, and in addition to this, other fibers such as the above-mentioned synthetic fibers may be used. It may further contain fibers. Similarly, the second fiber layer L2 may be composed only of the large-diameter fibers 12, and may further contain other fibers such as the cellulose fibers and synthetic fibers described above. Similarly, the third fiber layer L3 may be composed only of the small-diameter fibers 13, and may further contain other fibers such as the cellulose fibers and synthetic fibers described above. These can be used alone or in combination of two or more. Other fibers that may be included in each fiber layer may have a circular cross section (non-shaped) or may have a non-circular (non-shaped) cross section. The other fibers are preferably contained in each fiber layer in a proportion of 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less. In particular, it is preferable to use synthetic fibers containing a heat-fusible resin as the other fibers, since the constituent fibers can be fused to each other by application of heat, and the strength of the entire sheet can be increased.

From the viewpoint of ensuring sufficient strength during use of the wiping sheet 1, the thickness of the wiping sheet 1 is preferably 0.5 mm or more, and 0.8 mm or more in a dry state and under a load of 40 N/ ^m2 . It is more preferable that the thickness is 11.0 mm or less under the same load, and even more preferably that it is 10.0 mm or less.

The above has been a description of one embodiment of the wiping sheet of the present invention, and below, a preferred method of manufacturing the wiping sheet will be described with reference to FIGS. 7 and 8. 7 and 8 show a manufacturing apparatus 100 suitably used for manufacturing wiping sheets. This manufacturing method includes a step of laminating a fiber layer containing large diameter fibers 12 on the upper surface of a fiber layer containing hydrophilic fibers 11 to form a first laminate S1 (first lamination step); A step of laminating a fiber layer containing small diameter fibers 13 on the upper surface of the fiber layer to form a second laminate S2 (second lamination step), and a step of integrating the second laminate S2 (integration step). It is broadly divided into.

The manufacturing apparatus 100 shown in FIGS. 7 and 8 is equipped with a breathable conveyor belt 110 that is an endless belt. The conveyance belt 110 is provided with two conveyance rolls 111, 111, and is configured to draw a circular orbit in a single direction (conveyance direction MD).

Above the conveyor belt 110, there is a first fiber layer forming section 120 which forms a first fiber layer L1 containing hydrophilic fibers 11 in a laminated manner, and a second fiber layer L2 containing large diameter fibers 12 which forms a layer on top of the first fiber layer L1. A second fiber layer forming section 130 that forms a layer on the upper surface of the second fiber layer L2 is provided, and a third fiber layer forming section 140 that forms a third fiber layer L3 containing small diameter fibers 13 on the upper surface of the second fiber layer L2. . By passing through the forming portions 120, 130, and 140 in this order, it is possible to form the first laminate S1 and then form the second laminate S2.

Further, at a position facing each of the forming units 120 and 130, and on the lower surface side of the first laminate S1, there is a suction box for sucking the above-mentioned web toward the conveyor belt to form the first laminate S1. 150 are provided. In this way, the present manufacturing apparatus has a similar configuration to a manufacturing apparatus used in a general air-laid method.

The third fiber layer forming unit 140 in this embodiment is in the form of a raw fabric roll, and unrolls the third fiber layer L3 containing the small diameter fibers 13 as a long belt-shaped sheet to form the second fiber layer L2. It can be stacked on top.

An integration processing device 160 for integrating each fiber layer in the second laminate S2 is provided downstream of each forming section 120, 130, 140 in the transport direction MD. The integration processing device 160 shown in FIG. 7 is in the form of a water entangling device that integrates the laminated bodies by spraying a high-pressure water stream. In this embodiment, a water-permeable support belt 161 is provided at a position facing the integrated processing device 160 and is made of an endless belt stretched over a pair of support rolls 162 and is permeable to water. By spraying a high-pressure water stream onto the third fiber layer L3 side of the second laminate S2 introduced between the support belt 161 and the support belt 161, the constituent fibers can be intertwined and integrated.

The integration processing device 160 shown in FIG. 8 is a heating device that heats and integrates the second laminate S2. The integrated processing device 160 is capable of transporting the second stacked body S2 into its interior and heating the second stacked body S2. The manner of heating the second laminate S2 in the integrated processing device 160 includes, for example, a heater, spraying of heated gas, or infrared irradiation, and preferably spraying of heated gas. In this embodiment, when latent crimped fibers are used as the large diameter fibers 12, the second laminate S2 is integrated by heating, and the latent crimped fibers are crimped by applying heat, so that the crimped fibers are separated from the crimped fibers. The large diameter fiber 12 can be made as follows.

A preferred method for manufacturing a wiping sheet using the manufacturing apparatus 100 shown in FIGS. 7 and 8 is as follows. First, a fiber layer containing large-diameter fibers 12 is laminated on the upper surface of a fiber layer containing hydrophilic fibers 11 to form a first laminate S1 (first lamination step). In detail, from the first fiber layer forming section 120, the hydrophilic fibers 11 and, if necessary, other fibers such as synthetic fibers are supplied preferably uniformly in the belt surface direction, and the first fibers are A layer L1 is formed on the conveyor belt 110. After that, the large diameter fibers 12 and other fibers such as synthetic fibers are supplied from the second fiber layer forming section 130, and the second fiber layer L2 is laminated on the first fiber layer L1. , forming a first stacked body S1.

When forming the second fiber layer L2 over the entire area of the target wiping sheet 1 in the sheet surface direction, constituent fibers such as the large-diameter fibers 12 are supplied over the entire surface direction of the first fiber layer L1 and then supplied to the next process. do it. In addition, in order to form the non-existing region R2 on the wiping sheet 1, for example, in the surface direction of the first fiber layer L1, a region where constituent fibers such as the large diameter fibers 12 are supplied and a region where the large diameter fibers 12 and other parts to which constituent fibers are not supplied may be respectively formed and subjected to the next step. In this case, the region to which the constituent fibers such as the large-diameter fibers 12 are supplied becomes the presence region R1 in the wiping sheet 1, and the region to which the constituent fibers such as the large-diameter fibers 12 are not supplied becomes the non-present region R2.

Next, the third fiber layer L3 made of a fiber sheet containing the small-diameter fibers 13 is supplied from the third fiber layer forming section 140, and the third fiber layer L3 is laminated on the second fiber layer L2. A stacked body S2 is formed (second stacking step).

Subsequently, each fiber layer in the second laminate S2 is integrated by hydroentangling or heating (integration step). As shown in FIG. 7, when the integrated processing device 160 is in the form of a hydroentangling device, the second laminate S2 is conveyed in the MD direction by the support belt 161 while a high-pressure water stream is ejected from the integrated processing device 160. Confounding is handled by Through this process, the fibers of the second laminate S2 are intertwined with each other to form a fiber assembly 1A.

When the integrated processing device 160 is in the form of a hydroentangling device, the water pressure sprayed onto the second laminate S2 is preferably 30 kg/cm ² or more, more preferably 40 kg/cm ² or more, and preferably 80 kg/cm 2 or more. cm ² or less, more preferably 60 kg/cm ² or less. Further, the transport speed of the second laminate S2 in the MD direction is preferably 2 m/min or more, more preferably 4 m/min or more, and preferably 10 m/min or less, and even more preferably 8 m/min or less. can be manufactured.

As shown in FIG. 8, when the integrated processing device 160 is a heating device, the second fibrous layer L2 and the third fibrous layer L3 are preferably heated by spraying heated gas onto the second laminate S2. A part of the constituent fibers is melted, and the fibers making up the second laminate S2 are fused and integrated. In addition to this, if the first fiber layer L1 contains other fibers such as synthetic fibers containing heat-fusible resin, the heat-fusible resin contained in the other fibers may be melted by application of heat. , Due to this, the hydrophilic fibers 11 are further fused together and integrated. In addition, when a latent crimped fiber is used as the large-diameter fiber 12, crimping occurs due to the application of heat, resulting in a crimped fiber.

The heating temperature in the heating device can be adjusted as appropriate depending on the raw materials and melting points of the constituent fibers, but is preferably 130°C or higher, more preferably 140°C or higher, and preferably 200°C or lower, even more preferably 180°C or higher. below ℃. Further, the heat treatment time in the heating step can be preferably 10 seconds or more and 100 seconds or less within the above-mentioned temperature range. When spraying heated gas, the flow rate of the heated gas is preferably 540 m ³ /min or more, more preferably 550 m ³ /min or more, provided that the temperature and heating time are within the above-mentioned ranges, and Preferably it is 4600 m ³ /min or less, more preferably 4500 m ³ /min or less.

Specifically, the first fiber layer L1 includes pulp fibers as the hydrophilic fibers 11 and PET fibers as other fibers, and the eccentric layer L1 has a core made of PET and a sheath made of co-PET as the large diameter fibers 12. When blowing heated gas using the second fiber layer L2 containing latent crimped fibers which are core-sheath type composite fibers and the third fiber layer L3 containing polypropylene fibers as the small diameter fibers 13, the temperature is 150°C or higher. A heated gas of 170° C. or less can be sprayed at a flow rate of 2000 m ³ /min or more and 2500 m ³ /min or less, and for a heat treatment time of 20 seconds or more and 80 seconds or less.

Through the above steps, a fiber assembly 1A in which the fiber layers L1, L2, and L3 are laminated and integrated is manufactured. If it is desired to further strengthen the integration of each layer, a fusion process using heat embossing or ultrasonic embossing can be further performed. Further, the fiber aggregate 1A that has undergone hydroentanglement may be further subjected to the above-described heat treatment or fusion treatment.

In the manufacturing process of the wiping sheet 1, the large-diameter fibers 12 may be non-crimped fibers, crimped fibers that have developed crimps in advance, or latent crimped fibers. May be used. Particularly, in order to manufacture a wiping sheet containing crimped fibers as the large-diameter fibers 12, when performing an integration process by hydroentangling, crimped fibers that are crimped in advance can be used.

The fiber aggregate 1A manufactured as described above is formed into a predetermined shape, such as a rectangular shape, and then a cleaning liquid is supported on the fiber aggregate 1A to form a wet wiping sheet (supporting step, not shown). ). As a method for supporting the cleaning liquid in the supporting step, for example, the fiber aggregate 1A may be immersed in the cleaning liquid, or the fiber aggregate 1A may be sprayed with the cleaning liquid. In order to make at least the first fiber layer L1 carry the cleaning liquid, for example, the cleaning liquid may be sprayed or brought into contact with the first fiber layer L1 side of the fiber assembly 1A.

In the supporting step, the amount of cleaning liquid supported on the fiber aggregate 1A is preferably 960 g/m ² or more, more preferably 1120 g/m ² or more, preferably 1760 g/m ² or less, and even more preferably 1600 g/m ² or less. . In other words, the supporting ratio of the cleaning liquid to the mass of the fiber aggregate 1A in a dry state is preferably 300% by mass or more, more preferably 350% by mass or more, and preferably 550% by mass or less, even more preferably is 500% by mass or less.

The wiping sheet produced in this way can be used alone or attached to cleaning tools such as wipers to clean floors, walls, buildings, cupboards, window glasses, mirrors, etc., both outdoors and indoors. It can also be used for fittings such as doors and doorknobs, rugs, carpets, furniture such as tables and tables, kitchens, toilets, body cleaning, sanitary products, and packaging.

Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above embodiments. For example, although the third fiber layer L3 used in the manufacturing method has been described as a fiber sheet including the small diameter fibers 13, it is not limited to this format. For example, the third fiber layer L3 may be formed by directly spinning the small diameter fibers 13 onto the first laminate S1 using a melt-blowing method, an electrospinning method, or the like. Thereafter, a wet wiping sheet can be manufactured by performing an integration step and a supporting step.

Regarding the embodiment of the present invention described above, the following wet wiping sheet is further disclosed.

<1>
A first fiber layer containing hydrophilic fibers, a second fiber layer adjacent to the first fiber layer and containing large diameter fibers having a fiber diameter of 30 μm or more, and the first fiber layer in the second fiber layer are arranged. a third fiber layer that is adjacent to the side that is not covered and includes small fibers with a fiber diameter of 2 μm or less,
A wet wiping sheet having a basis weight of 110 g/m ² or more and carrying a cleaning liquid.

<2>
The large diameter fibers have penetrated into the third fiber layer side beyond the interface between the second fiber layer and the third fiber layer,
Wet wiping according to <1>, wherein the large diameter fibers and the small diameter fibers are present on the surface of the third fiber layer on the side where the first fiber layer and the second fiber layer are not arranged. sheet.
<3>
having a first surface and a second surface located on the opposite side of the first surface,
The wet wiping sheet according to <2>, wherein the surface of the third fiber layer constitutes the first surface.
<4>
The wet wiping sheet according to <3>, wherein the first surface is a wiping surface that is used in contact with a surface to be cleaned during use.
<5>
The number of the large diameter fibers present on the surface of the third fiber layer is preferably 400 fibers/cm ² or more, more preferably 500 fibers/cm ² or more, and preferably 3200 fibers/cm ² The wet wiping sheet according to any one of <2> to <4>, further preferably 3000 pieces/cm ² or less.
<6>
A region where the second fiber layer does not exist is formed between the first fiber layer and the third fiber layer,
The region is a wet type according to any one of <1> to <5>, in which the fibers constituting the first fiber layer and the fibers constituting the third fiber layer are directly fused or intertwined. wiping sheet.

<7>
A region where the second fiber layer exists between the first fiber layer and the third fiber layer, and a region where the second fiber layer does not exist between the first fiber layer and the third fiber layer. The wet wiping sheet according to any one of <1> to <6>, wherein a plurality of strip-shaped regions are formed alternately so as to extend in one direction.
<8>
The wet wiping sheet according to any one of <1> to <7>, wherein the large diameter fibers are crimped fibers.
<9>
The number of crimps in the crimped fiber is preferably 1 or more, more preferably 2 or more, and the upper limit thereof is preferably 10 or less, and even more preferably 8 or less. The wet wiping sheet described in 8>.
<10>
The wet wiping sheet according to any one of <1> to <9>, wherein the large diameter fiber is a composite fiber of polyethylene terephthalate and polyethylene.
<11>
The basis weight is preferably 110 g/m ² or more, more preferably 115 g/m ² or more, even more preferably 120 g/m ² or more, and preferably 360 g/m ² or less, more preferably 355 g/m ² The wet wiping sheet according to any one of <1> to <10>, further preferably 350 g/m ² or less.
<12>
The basis weight of the first fiber layer is preferably 50 g/m ² or more, more preferably 55 g/m ² or more, even more preferably 60 g/m ² or more, and preferably 160 g/m ² or less, more preferably The wet wiping sheet according to any one of <1> to <11>, wherein the weight is 155 g/m ² or less, more preferably 150 g/m ² or less.

<13>
The basis weight of the second fiber layer is preferably 35 g/m ² or more, more preferably 40 g/m ² or more, even more preferably 45 g/m ² or more, and preferably 115 g/m ² or less, more preferably The wet wiping sheet according to any one of <1> to <12>, wherein the weight is 110 g/m ² or less, more preferably 105 g/m ² or less.
<14>
The wet wiping sheet according to any one of <1> to <13>, wherein the third fiber layer has a basis weight of 20 g/m ² or more and 50 g/m ² or less.
<15>
The basis weight of the third fiber layer is more preferably 22 g/m ² or more, still more preferably 25 g/m ² or more, more preferably 48 g/m ² or less, still more preferably 45 g/m ² or less. The wet wiping sheet according to any one of <1> to <14> above.
<16>
The fiber diameter of the hydrophilic fiber is preferably 5 μm or more, more preferably 8 μm or more, and preferably 53 μm or less, further preferably 50 μm or less, according to any one of <1> to <15> above. Wet wiping sheet listed.
<17>
The fiber diameter of the large diameter fiber is preferably 30 μm or more, more preferably 35 μm or more, and preferably 105 μm or less, further preferably 100 μm or less, according to any one of <1> to <16> above. Wet wiping sheet listed.

<18>
The wet wiping sheet according to any one of <1> to <17>, wherein the fine fibers have a fiber diameter of preferably 2 μm or less, more preferably 1.8 μm or less, and 0.1 μm or more.
<19>
The ratio (D2/D1) of the fiber diameter of the large diameter fiber to the fiber diameter D1 of the hydrophilic fiber is preferably 1.0 or more, more preferably 1.2 or more, and preferably 12 or less, even more preferably 10 or less, the wet wiping sheet according to any one of <1> to <18> above.
<20>
The ratio (D3/D1) of the fiber diameter D3 of the small diameter fiber to the fiber diameter D1 of the hydrophilic fiber is preferably 0.008 or more, more preferably 0.010 or more, and preferably 0.08 or less, The wet wiping sheet according to any one of <1> to <19> above, which is more preferably 0.06 or less.
<21>
The thickness in a dry state and under a load of 40 N/ ^m2 is preferably 0.5 mm or more, more preferably 0.8 mm or more, preferably 11.0 mm or less, and 10.0 mm or less. The wet wiping sheet according to any one of <1> to <20>, which is more preferably.

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

[Example 1]
As the hydrophilic fibers 11, pulp with an average fiber diameter of 12 μm was used. As the large-diameter fiber 12, an eccentric core-sheath type fiber having an average fiber diameter of 44 μm and having a PET core and a co-PET sheath was used. As the small diameter fibers 13, PP fibers having an average fiber diameter of 1 μm were used. Hydrophilic fibers 11 (pulp): PET fibers are contained in a mass ratio of 4.0:6.0, and the first fiber layer L1 is made of a mixed cotton material whose constituent fibers have an average fiber diameter of 11.4 μm, and large diameter fibers. A second fiber layer L2 made of 12 fibers and a third fiber layer L3 made of a nonwoven fabric made of 13 small diameter fibers were used. The basis weight of the first fiber layer L1 was 110 g/m ² . The basis weight of the second fiber layer L2 was 75 g/m ² . The basis weight of the third fiber layer L3 was 30 g/m ² . These fiber layers were integrated by an air-laid method and a spunlace method to obtain a fiber aggregate 1A having a basis weight of 215 g/m ² .

In this example, each of the fiber layers L1, L2, and L3 was formed over the entire area in the sheet surface direction, as shown in FIG. 1, and no non-existing region R2 was formed. Further, the large diameter fibers 12 are crimped fibers, and the large diameter fibers 12 cross the boundary between the second fiber layer L2 and the third fiber layer L3 and enter the third fiber layer L3 side, and the large diameter fibers 12 enter the third fiber layer L3 side. Both large diameter fibers 12 and small diameter fibers 13 were present on the surface of L3.

Next, the above-described fiber aggregate 1A was impregnated with a cleaning liquid to produce a wet wiping sheet. The cleaning liquid was impregnated so that at least the first fiber layer L1 was supported. The amount of impregnation of the cleaning liquid was 400% by mass as a mass ratio to the mass of the fiber aggregate 1A in a dry state. The composition of the cleaning liquid was an aqueous solution containing 0.3% by mass of polyoxyethylene lauryl ether. The wiping sheet was rectangular, and its dimensions were 285 mm x 205 mm.

[Examples 2 to 4]
A wet wiping sheet was used in the same manner as in Example 1, except that the basis weight of the third fiber layer L3 was changed to 7 g/m ² , 15 g/m ² , or 45 g/m ² to produce the fiber aggregate 1A. Manufactured.

[Example 5]
Example 1 was carried out in the same manner as in Example 1, except that as the large-diameter fiber 12, an eccentric core-sheath type fiber having a PET core and a PE sheath and an average fiber diameter of 50 μm was used, and the second fiber layer L2 made of the fiber was used. A wet wiping sheet was manufactured. The large diameter fibers 12 in this example were crimped fibers, and both the large diameter fibers 12 and the small diameter fibers 13 were present on the surface of the third fiber layer L3.

[Example 6]
As shown in FIG. 5, the second fiber layer L2 was formed so that a plurality of existence regions R1 and non-existence regions R2 existed alternately in a band shape, and the fiber assembly 1A was manufactured. A wet wiping sheet was manufactured in the same manner.

[Example 7]
A wet wiping sheet was produced in the same manner as in Example 1, except that the cleaning liquid to be impregnated was changed to only ion-exchanged water.

[Comparative example 1]
A wet wiping sheet comprising a fiber aggregate consisting of a fiber web and a reticulated sheet was produced according to the method described in JP-A No. 2007-154359. The fiber web contained rayon:acrylic fiber:PET fiber in a mass ratio of 25:25:50, and had a basis weight of 60 g/ ^m2 . Further, the mesh sheet was made of PP and had a basis weight of 5 g/m ² . The basis weight of the fiber aggregate was 65 g/m ² . This fiber aggregate was impregnated with a cleaning liquid in an amount of 400% by mass based on the mass of the fiber aggregate in a dry state. The composition of the cleaning liquid was a 0.3% by mass aqueous solution of polyoxyethylene lauryl ether. The wiping sheet was rectangular, and its dimensions were 285 mm x 205 mm.

[Comparative example 2]
A wet wiping sheet was produced in the same manner as in Example 1, except that the fiber aggregate was produced without providing the third fiber layer L3. The wet wiping sheet of this comparative example has a fiber aggregate having a basis weight of 60 g/m ² and has a two-layer structure consisting of a first fiber layer L1 and a second fiber layer L2.

[Comparative example 3]
A wet wiping sheet was produced in the same manner as in Comparative Example 1, except that only ion-exchanged water was impregnated as the cleaning liquid.

[Evaluation 1: Evaluation of sustained release properties of cleaning solution]
A load of 0.16 kN/ ^m2 was applied to the wet wiping sheets of Examples 1 to 6 and Comparative Examples 1 to 2 to form a rectangular tile floor (Lixil) with dimensions of 0.6 m x 0.6 m per sheet. Wiping was carried out on 36 sheets (equivalent to 12.96 m ² ) of Charlotte II (manufactured by Co., Ltd.) as the surface to be cleaned. Wiping was performed at a wiping speed of 1 m/s by moving the sheet back and forth four times over an area equivalent to half a tatami mat (0.9 m x 0.9 m), covering the entire surface to be cleaned. Based on the initial loading amount (g) of the cleaning liquid on the wiping sheet used, the amount (g) of cleaning liquid released onto the tile floor by wiping and the residual amount (g) of the cleaning liquid remaining on the wiping sheet are calculated as follows: Each time an area equivalent to a tatami mat (1.8 m x 0.9 m) was wiped, measurements were taken to evaluate the sustained release properties of the cleaning liquid. In addition, the percentage of the remaining amount (g) of the cleaning solution after wiping (after wiping 36 tile floors) with respect to the initial supported amount (g) of the cleaning solution was calculated to evaluate the usage efficiency of the cleaning solution. The results are shown in FIGS. 9(a) and (b) and FIGS. 10(a) and (b). In the graphs shown in FIGS. 9A and 10A, the left side of the horizontal axis indicates the start of wiping, and the right side of the horizontal axis indicates the end of wiping.

As shown in FIGS. 9(a) and (b), the wet wiping sheets of the examples have a higher amount of cleaning liquid supported than the wet wiping sheets of the comparative examples, and the wet state of the wiping sheets is maintained for a longer period of time. It can be seen that the sustained release properties of the cleaning liquid are good. In particular, in Examples 1 and 4, in which the basis weight of the third fiber layer L3 is set to a suitable range, the amount of cleaning liquid supported is further increased, and a large amount of cleaning liquid is easily released continuously at the initial stage of wiping. It can be seen that since the efficiency of use of the cleaning liquid is high, the sustained release of the cleaning liquid from the start to the end of wiping is particularly excellent, and it is possible to wipe a wide area with a single wiping sheet.

In addition, as shown in FIGS. 10(a) and (b), Example 5 in which the resin constituting the large diameter fibers 12 in the second fiber layer L2 is changed to a suitable one, and the area where the second fiber layer L2 does not exist Example 6, in which R2 was formed, has a higher amount of cleaning liquid supported and a higher usage efficiency of the cleaning liquid, so it is particularly excellent in sustained release of the cleaning liquid from the start to the end of wiping, and can be used with a single wiping sheet. It can also be seen that it is possible to wipe a wide area.

[Evaluation 2: Evaluation of operability]
The wiping sheets of Example 7 and Comparative Example 3 were used to evaluate the operability based on the wiping resistance value. A weight of 1 kg and a plane size of 75 mm x 80 mm (load: equivalent to 1.63 kN/ ^m2 ) was placed on the wet wiping sheet to be evaluated to clean the entrance tile floor (manufactured by Nittai Kogyo Co., Ltd., Romani II) with a rough surface. The resistance force (N) when used as a target surface was measured. To measure the resistance force, a hook-shaped clip is attached to the tip of a push-pull gauge (RX-20, manufactured by Aiko Engineering Co., Ltd.), and a special jig on which the wiping sheet to be evaluated is attached is attached to the clip. The maximum load recorded on the push-pull gauge when this dedicated jig was scanned for 20 mm on a tile floor at a speed of 300 mm/min was defined as the resistance force (N). The measurement was performed five times, and the arithmetic mean value was calculated. The lower the resistance, the higher the operability during use. The results are shown in FIG.

As shown in FIG. 11, it can be seen that the wet wiping sheet of the example has lower frictional resistance and higher operability during use than the wet wiping sheet of the comparative example. Furthermore, after the measurement, the wet wiping sheet of the example showed no defects such as peeling or fraying of the constituent fibers, and it was found that it had sufficient strength even when wiping a rough surface to be cleaned.

[Evaluation 3: Evaluation of dirt collection ability]
Using the wiping sheets of Example 7 and Comparative Example 3, an outdoor concrete floor to which dust and grit had adhered was wiped as a surface to be cleaned, and dirt collection performance was evaluated. Wiping in this evaluation was performed by placing a weight of 1.5 kg and 50 mm x 80 mm (load: equivalent to 3.75 kN/ ^m2 ) on the wiping sheet, and moving it back and forth in the front and rear directions three times over a 15 cm area. Ta. The results are shown in FIG. In the image of the surface to be cleaned in FIG. 12, the black and gray parts are the parts where dirt remains, and the white parts are the parts from which the dirt has been removed.

As shown in Figure 12, the wiping sheet of the example can be wiped without fraying or breaking the fibers after wiping, scraping off dirt attached to the surface to be cleaned, and collecting dirt on the sheet. It can be seen that it can be maintained. On the other hand, in the wiping sheet of the comparative example, peeling of fibers was observed after wiping was completed, and the dirt collection performance was not sufficient.

1 Wet wiping sheet 1A Fiber aggregate 1F First surface 1R Second surface 11 Hydrophilic fiber 12 Large diameter fiber 13 Small diameter fiber L1 First fiber layer L2 Second fiber layer L3 Third fiber layer Z Thickness direction 100 Manufacturing equipment

Claims (7)

A first fiber layer containing hydrophilic fibers, a second fiber layer adjacent to the first fiber layer and containing large diameter fibers having a fiber diameter of 30 μm or more, and the first fiber layer in the second fiber layer are arranged. a third fiber layer that is adjacent to the side that is not covered and includes small fibers with a fiber diameter of 2 μm or less,
No other fiber layer is arranged on the first surface of the third fiber layer, which is the side on which the first fiber layer and the second fiber layer are not arranged,
the first surface is a wiping surface;
A wet wiping sheet having a basis weight of 110 g/m ² or more and carrying a cleaning liquid. A first fiber layer containing hydrophilic fibers, a second fiber layer adjacent to the first fiber layer and containing large diameter fibers having a fiber diameter of 30 μm or more, and the first fiber layer in the second fiber layer are arranged. a third fiber layer that is adjacent to the side that is not covered and includes small fibers with a fiber diameter of 2 μm or less,
A region where the second fiber layer does not exist is formed between the first fiber layer and the third fiber layer,
In the region, the fibers constituting the first fiber layer and the fibers constituting the third fiber layer are directly fused or intertwined,
A wet wiping sheet having a basis weight of 110 g/m ² or more and carrying a cleaning liquid. The large diameter fibers have penetrated into the third fiber layer side beyond the interface between the second fiber layer and the third fiber layer,
The wet method according to claim 1 or 2, wherein the large diameter fibers and the small diameter fibers are present on the surface of the third fiber layer on the side where the first fiber layer and the second fiber layer are not arranged. wiping sheet. The wet wiping sheet according to any one of claims 1 to 3, wherein the large diameter fibers are crimped fibers. The wet wiping sheet according to any one of claims 1 to 4, wherein the large diameter fiber is a composite fiber of polyethylene terephthalate and polyethylene. The wet wiping sheet according to any one of claims 1 to 5, wherein the third fiber layer has a basis weight of 20 g/m ² or more and 50 g/m ^{2 or} less. Any one of claims 1 to 6, wherein no other fiber layer is arranged on a second surface of the first fiber layer, which is a side on which the second fiber layer and the third fiber layer are not arranged. The wet wiping sheet described in item 1.

Images