JP2021090660A - Wet type wiping sheet - Google Patents

Abstract

To provide a wet type wiping sheet that has achieved both liquid slow releasing performance and dirt collecting property at a high level.SOLUTION: A wet type wiping sheet 1 includes, in a plane view, a central region C extending in one direction and a pair of lateral regions S adjacent to the central region C and extending in the one direction, and is formed by carrying cleaning liquid. The wet type wiping sheet 1 is used by being mounted in such a manner that the central region C is located on an undersurface 210B of a head part 210 in a cleaning tool 220 equipped with the head part 210 having a fixing part 211 of the wiping sheet 1 on a top surface 210A, and the lateral regions S are fixed by the fixing part 211 on the top surface 210A. The central region C includes a first fiber layer L1 containing hydrophilic fibers 11 and a second fiber layer L2 adjacent to each surface of the first fiber layer L1, containing large-diameter fibers 12 with a fiber diameter of 30 μm or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wet wiping sheet.

Cellulose fibers and fiber aggregates in which fibers made from thermoplastic resins are fused or entangled are used for various purposes. The applicant has a first surface and a second surface opposite to the first surface, and is composed of a fiber aggregate of at least two kinds of fibers having different fiber diameters, and the wiping liquid is at least the second surface. We have proposed a wet wiping sheet supported on a fiber assembly on the surface side (Patent Document 1). In this sheet, the fibers are entangled with each other, and the proportion of fibers having a small fiber diameter is higher on the first surface side than on the second surface side, and the proportion of fibers having a large fiber diameter is higher than that on the first surface side. There are many on the two-sided side, and the capillary pressure on the first-sided side is higher than that on the second-sided side.

Further, in Patent Document 2, an ultrafine fiber layer containing 50% by weight or more of split-type composite fibers is arranged on at least one surface of the hydrophilic fiber layer containing 50% by weight or more of hydrophilic fibers, and three-dimensional entanglement is performed. A non-woven fabric for cleaning, which is made of a composite non-woven fabric that is integrated by a combination, is disclosed. It is also disclosed in the same document that the non-woven fabric for cleaning has an average fiber length of less than 20 mm for the fibers constituting the hydrophilic fiber layer and an average fiber length of 30 to 100 mm for the fibers constituting the ultrafine fiber layer. ing.

Patent Document 3 describes a surface layer mainly composed of a first direction and a second direction intersecting the first direction, long fibers having an average fiber diameter of 10 μm or less and having hygroscopicity, and short fibers having an average fiber diameter of more than 10 μm. A wiping sheet having a mainly configured back surface layer is disclosed. In this wiping sheet, in the front surface layer, the long fibers irregularly arc and spread uniformly in a mesh pattern, and in the back surface layer, a plurality of openings arranged in the first direction are formed, and the long fibers are described above. It is also disclosed in the same document that it straddles at least a part of the openings.

JP-A-2018-89348 Japanese Unexamined Patent Publication No. 2001-190469 International Publication No. 2016/132790 Pamphlet

The wiping sheet described in Patent Document 1 can be wiped lightly to remove stains, and even if the wiping area is large, the number of replacements is small. There was room for improvement. Further, the non-woven fabrics and sheets of Patent Documents 2 and 3 do not have both liquid sustained release property and dirt collection property at a high level. Further, the sheets described in each patent document have not been examined for the sustained release property of the liquid when used by being attached to a cleaning tool, and there is room for improvement in this respect as well.

Therefore, an object of the present invention is to provide a wet wiping sheet having both liquid sustained release property and dirt collection property at a high level.

The present invention is a wet wiping sheet having a central region extending in one direction and a pair of lateral regions extending in one direction adjacent to the central region in a plan view.
In the wet wiping sheet, the central region is located on the lower surface of the head portion of a cleaning tool having a head portion having a fixed portion of the wet wiping sheet on the upper surface, and the lateral region is formed by the fixing portion on the upper surface. It is used by being attached to the head portion so as to be fixed.
The central region has a first fiber layer containing hydrophilic fibers and a second fiber layer containing thick fibers having a fiber diameter of 30 μm or more adjacent to each surface of the first fiber layer.
A wet wiping sheet on which a cleaning liquid is supported is provided.

According to the present invention, there is provided a wet wiping sheet having both liquid sustained release property and dirt collection property at a high level.

FIG. 1 (a) is a schematic perspective view of the wet wiping sheet of the present invention as viewed from the lower surface side showing one embodiment and a preferred mode of use, and FIG. 1 (b) is a schematic view of the wet wiping sheet of the present invention. It is a perspective schematic diagram which shows one Embodiment which attached to the cleaning tool. FIG. 2 is a schematic perspective view showing an embodiment of the wet wiping sheet of the present invention. FIG. 3A is an embodiment of a schematic cross-sectional view of the wet wiping sheet shown in FIG. 2 on the I-I plane, and FIG. 3B is another schematic cross-sectional view on the I-I plane. Is an embodiment of. FIG. 4 is a schematic perspective view showing another embodiment of the wet wiping sheet of the present invention. FIG. 5 (a) is an embodiment of a schematic cross-sectional view of the wet wiping sheet shown in FIG. 4 on the II-II plane, and FIG. 5 (b) is another schematic cross-sectional view on the II-II plane. Is an embodiment of. FIG. 6 is a magnified observation image by a scanning electron microscope showing a laminated state of the first to third fiber layers in a cross section in the thickness direction of the wet wiping sheet. FIG. 7 (a) is another magnified observation image showing the laminated state of the second and third fiber layers in the cross section in the thickness direction of the wet wiping sheet, and FIG. 7 (b) is shown in FIG. 7 (a). It is an observation image by a scanning electron microscope on the 1st surface of a wet wiping sheet. FIG. 8 is a schematic perspective view showing still another embodiment of the wet wiping sheet of the present invention. 9 (a) is an embodiment of a schematic cross-sectional view of the wet wiping sheet shown in FIG. 8 on the III-III plane, and FIG. 9 (b) is another schematic cross-sectional view on the III-III plane. Is an embodiment of. FIG. 10 is a schematic view showing an embodiment of a manufacturing apparatus preferably used for manufacturing the wet wiping sheet of the present invention. FIG. 11 is a schematic view showing another embodiment of a manufacturing apparatus preferably used for manufacturing the wet wiping sheet of the present invention. FIG. 12 is a graph showing the relationship between the retention amount and the release amount of the cleaning liquid when the wet wiping sheets of Examples and Comparative Examples are used. FIG. 13 is a photograph showing the collectability of dirt when the wet wiping sheets of Examples and Comparative Examples are used.

Hereinafter, the wet wiping sheet of the present invention will be described based on its preferred embodiment. In the present invention, "wiping" includes both cleaning and cleaning of the surface of an object to be cleaned, for example, cleaning of buildings such as floors, walls, ceilings and pillars, and cleaning of fittings and equipment. , Wiping of articles, cleaning of the body and equipment related to the body, etc. are included. Further, in the present invention, the “wet” refers to a material in which a cleaning liquid is supported on a fiber aggregate constituting the sheet.

1 (a) and 1 (b) show one embodiment of the wet wiping sheet of the present invention and a preferred mode of use. The wet wiping sheet 1 (hereinafter, also simply referred to as “wiping sheet 1”) shown in FIGS. 1 (a) and 1 (b) has a substantially rectangular shape in a plan view, and has a central region extending in one direction. It has C and a pair of side regions S and S adjacent thereto and extending in the same direction as the central region C. The central region C and the lateral region S each extend in the longitudinal direction of the wiping sheet 1. Each of the side regions S can be bent along a bending line FL extending in the longitudinal direction of the wiping sheet 1. Further, the wiping sheet 1 has a first surface 1F and a second surface 1R located on the opposite side of the first surface 1F. In the present embodiment, the first surface 1F and the second surface 1R, which are the surfaces of the second fiber layer L1, can be used as the wiping surface used in contact with the surface to be cleaned when the wiping sheet 1 is used. In the wiping sheet 1 shown in FIGS. 1A and 1B, the first surface 1F is used as the wiping surface.

As shown in FIGS. 1A and 1B, the wiping sheet 1 is preferably used as an aspect of the cleaning tool 200 attached to the cleaning tool 220. The cleaning tool 220 shown in the figure includes a head portion 210 to which the wet wiping sheet 1 can be attached. As shown in FIGS. 1A and 1B, the head portion 210 is a rectangular member, and a plurality of fixing portions 211 for fixing the wiping sheet 1 are provided on the upper surface 210A of the head portion 210. In the head portion 210, the second surface 1R of the wiping sheet 1 and the lower surface 210B of the head portion 210 face each other, and the wiping sheet can be attached so as to cover the lower surface 210B. Further, the cleaning tool 220 is composed of, for example, a rod-shaped member that can be expanded and contracted or can be extended by assembly, a member having a handle, or a member that combines these.

Further, as shown in FIGS. 1A and 1B, it is preferable that the wiping sheet 1 is attached so that the longitudinal direction of the wiping sheet 1 and the longitudinal direction of the head portion 210 coincide with each other. Therefore, when the wiping sheet 1 is attached to the cleaning tool 220, it is dirty that the central region C is attached so as to be located on the lower surface 210B of the head portion and the first surface 1F faces the surface to be cleaned. It is preferable in that it enhances the collection performance of. In this case, since the pair of side regions S and S are regions extending from the side edges of the head portion 210, each side region S is folded back along the bending line FL or its vicinity, and each side The regions S and S are attached to the head portion 210 so as to be fixed by the fixing portion 211.

The wiping sheet 1 includes a fiber assembly including a plurality of fiber layers in the central region C thereof. Specifically, the central region C of the wiping sheet 1 includes a first fiber layer containing hydrophilic fibers and a large-diameter fiber having a fiber diameter of preferably 30 μm or more (hereinafter, this fiber is also simply referred to as “thick-diameter fiber”. ) Is provided, and the second fiber layer is arranged adjacent to each surface of the first fiber layer. In addition to this, a third fiber containing a small diameter fiber having a fiber diameter of preferably 2 μm or less (hereinafter, this fiber is also simply referred to as “small diameter fiber”) in the central region C on one surface of the wiping sheet 1. It is also preferable that the layer is arranged adjacent to the second fiber layer. In either case, these fibers are integrated by at least one aspect of fusion and entanglement to form the fiber assembly described above. The central region C in the wiping sheet 1 may be composed of only the fiber aggregates, or may include other sheet materials, other members, or both in addition to the fiber aggregates.

On the other hand, since the side area S is an area that is folded back when attached to the cleaning tool 220, for example, the contact area with the cleaning target surface is smaller than that of the central area C, or the side area S and the cleaning target surface. Does not come into contact with. Therefore, the lateral region S may be composed of a fiber aggregate composed of only a single layer of the first fiber layer, or may be composed of a fiber aggregate composed of the first fiber layer and the second fiber layer. .. Instead of this, it may be composed of a fiber aggregate composed of a first fiber layer, a second fiber layer and a third fiber layer so as to have the same structure as the central region C.

In the following description, the configuration of the central region C will be focused on. 2 and 3 (a) and 3 (b) show an embodiment of the fiber assembly provided in the wet wiping sheet of the present invention. The fiber assembly 1A shown in the figure contains a first fiber layer L1 containing hydrophilic fibers 11 and large-diameter fibers 12 on each surface of the fiber layer L1 and is adjacent to each surface of the first fiber layer L1. It has a three-layer structure having a second fiber layer L2 arranged therein. These fiber layers L1 and L2 are integrated to form a fiber assembly 1A. The fiber layers L1 and L2 in the present embodiment are arranged over the entire area of the wiping sheet 1 in a plan view, and the second fiber layer L2 forms the surfaces 1F and 1R, respectively.

In the wiping sheet 1 shown in FIGS. 2 and 3 (a) and 3 (b), no other fiber layer is arranged on each of the surfaces 1F and 1R on which the second fiber layer L2 is arranged. Therefore, the large-diameter fibers 12 are mainly present on both the first surface 1F and the second surface 1R. "Mainly present" means that the abundance ratio of fibers on the above-mentioned surface is the highest when the wiping sheet 1 is viewed in a longitudinal section along the thickness direction Z.

As shown in FIG. 2, the fiber layers L1 and L2 constituting the wiping sheet 1 may be present with the boundary surface of each fiber layer clearly defined, and are shown in FIGS. 3 (a) and 3 (b). As described above, the boundary surface of each fiber layer may be obscured and exist. In any case, when the wiping sheet 1 is viewed along the thickness direction Z, the abundance ratio of the constituent fibers in each fiber layer changes stepwise, continuously, or in a combination thereof. Is preferable.

When the boundary surface of each fiber layer is unclear, it is preferable that the fibers constituting one fiber layer penetrate the other fiber layer beyond the boundary surface of the adjacent layer, and such a configuration. As a result, the supported cleaning liquid can be easily supplied to the surface to be cleaned via each fiber layer, so that the sustained release property is improved. As a specific example of such an embodiment, as shown in FIGS. 3A and 3B, the hydrophilic fiber 11 crosses the boundary surface between the first fiber layer L1 and the second fiber layer L2 and is the second fiber. Examples thereof include a mode in which the large-diameter fibers 12 invade the layer L2 side and a mode in which the large-diameter fibers 12 invade the first fiber layer L1 side beyond the boundary surface between the first fiber layer L1 and the second fiber layer L2.

In particular, in the wiping sheet 1 of the present embodiment, the hydrophilic fibers 11 penetrate the second fiber layer L2 side beyond the boundary surface between the first fiber layer L1 and the second fiber layer L2, and the hydrophilic fibers It is preferable that the 11 and the large-diameter fiber 12 are present on at least one of the first surface 1F and the second surface 1R. With such a configuration, the sustained release property of the liquid to the surface to be cleaned is enhanced, and wiping in a wide range becomes possible. In addition to this, the high-rigidity large-diameter fiber 12 scrapes off the dirt adhering to the surface to be cleaned to float the dirt, so that the dirt can be efficiently collected.

From the viewpoint of enhancing the sustained release of the liquid to the surface to be cleaned, the number of hydrophilic fibers 11 existing on the first surface 1F, which is the wiping surface of the wiping sheet 1, is preferably 30 fibers / cm ² or more, and further. It is preferably 50 lines / cm ² or more, preferably 6000 lines / cm ² or less, and more preferably 5000 lines / cm ² or less. The number of hydrophilic fibers 11 existing on the wiping surface of the wiping sheet 1 is the total mass (g / cm ² ) per unit area in the flat area of the wiping sheet 1, and the mass of the hydrophilic fibers 11 per one. It can be a value divided by (g).

Examples of the hydrophilic fiber 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) and the like. Polyolefin fiber, polyester fiber such as polyethylene terephthalate (PET), PE and PET, mixed fiber of polyolefin and polyester such as PP and PET, polyamide fiber such as nylon 6 and nylon 66, vinyl type such as polyvinyl chloride and polystyrene. Examples thereof include fibers, acrylic fibers such as polyacrylonitrile, and fibers obtained by hydrophilizing synthetic fibers such as fluororesins such as polyperfluoroethylene, and among these, pulp and rayon are preferably used. These can be used alone or in combination of two or more. The hydrophilic fiber means a fiber in which the 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 Japanese Patent Application Laid-Open No. 2015-142721.

From the viewpoint of further improving the retention and sustained release of the cleaning liquid, the fiber diameter D1 of the hydrophilic fiber 11 is preferably smaller than the fiber diameter D2 of the large diameter fiber 12. Specifically, 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, further preferably 50 μm or less. For the fiber diameter D1 of the hydrophilic fiber 11, for example, the longest length in the fiber cross section orthogonal to the fiber length direction can be measured using a scanning electron microscope or the like. Such hydrophilic fibers 11 can be obtained by, for example, mechanically defibrating pulp paperboard with a hammer mill or the like, and the fibers obtained by this method are generally short fibers.

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

From the viewpoint of improving the scraping property of dirt and enhancing the collecting property of dirt, the fiber diameter D2 of the large diameter fiber 12 is preferably 30 μm or more, more preferably 32 μm or more, and preferably 105 μm or less, further. It is 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 a large-diameter fiber 12 can be obtained by, for example, cutting continuous tow fibers to a predetermined length with a rotary staple cutter, and the fibers obtained by the method are generally short fibers. is there. The large-diameter fibers 12 existing in one second fiber layer L2 and the large-diameter fibers 12 existing in the other second fiber layer L2 have the same material, shape, and fiber diameter D2. It may be present or different.

From the viewpoint of improving both liquid retention and dirt collection, the ratio (D2 / D1) of the fiber diameter D2 of the thick fiber 12 to the fiber diameter D1 of the hydrophilic fiber 11 is preferably 1.0 or more. , More preferably 1.2 or more, preferably 12.0 or less, still more preferably 10.0 or less. When the fiber diameters D2 of the large-diameter fibers 12 are different in each of the second fiber layers L2, the large-diameter fibers 12 existing in the respective second fiber layers L2 may satisfy the above ratio.

As described above, the wiping sheet 1 is a wet mode in which a cleaning liquid mainly composed of water is supported on the fiber aggregate, and the cleaning liquid is preferably supported on at least the first fiber layer L1. The content of water contained in the cleaning liquid is preferably 80.0% by mass or more, more preferably 90.0% by mass or more, and 100% by mass or less with respect to the total mass of the cleaning liquid. It is preferable, and it is more preferable that it is 99.0% by mass or less.

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

Since the wiping sheet 1 having the above configuration has the first fiber layer L1 containing the hydrophilic fibers 11, a large amount of cleaning liquid can be retained, and as a result, the wiping sheet is kept wet when used. Can be kept for a long time. Further, the large-diameter fiber 12 contained in the second fiber layer L2 can improve the scraping property of dirt adhering to the surface to be cleaned and enhance the collecting property of dirt.

In particular, the wiping sheet 1 is provided with the second fiber layer L2 on each surface of the first fiber layer L1 in the central region C thereof, so that the cleaning liquid is excellently released during wiping. Specifically, since the second fiber layer L2 has a large-diameter fiber 12 having a larger fiber diameter than the hydrophilic fiber 11, the structure has a large inter-fiber distance and many voids. In addition to this, since the large diameter fiber 12 has high fiber rigidity due to the large fiber diameter, it is likely to repel the pressing force generated when the wiping sheet 1 is used, and the central region C is pressed. However, the voids existing in the second fiber layer L2 are maintained.

Generally, the wet wiping sheet is used by a method such as gripping it by hand or attaching it to the cleaning tool 220 described above. When the wet wiping sheet is used, the central region of the sheet is manually and the surface to be cleaned. It is pressed between the cleaning tools and the surface to be cleaned. At this time, the cleaning liquid supported on the wiping sheet is pushed out from the fiber aggregate arranged in the central region by the pressing force generated by the use of the wiping sheet, and is discharged to the sheet surface. As shown in the prior art, a sheet having a single layer structure composed of only the first fiber layer L1 or a second fiber layer L2 is arranged only on one surface of the first fiber layer L1 and the first fiber layer L1. When the two-layer structure sheet is used for wiping, the cleaning liquid is directly discharged from the first fiber layer by pressing the wiping sheet against the surface to be cleaned. The cleaning liquid tends to be excessively discharged to the side of the manual or cleaning tool that comes into direct contact with the cleaning tool, or to the side of the contact surface between the first fiber layer arranged in the central region and the surface to be cleaned. As a result, the cleaning liquid is sufficiently released immediately after the start of wiping, but when wiping using this sheet continuously, the amount of liquid released may be reduced and the dirt collection and removal performance may not be sufficiently exhibited. ..

In this regard, according to the wiping sheet of the present invention, since the second fiber layer is arranged in the central region C on each surface of the first fiber layer L1, the cleaning liquid supported on the first fiber layer L1 is both. It is supplied to the second fiber layers L2 and L2. The cleaning liquids supplied to both the second fiber layers L2 and L2 are retained in the voids of the respective fiber layers L2, and the cleaning liquids that are not retained are gradually released to the sheet surface so as to seep out. As a result, the cleaning liquid is continuously supplied to the surface of the wiping sheet 1 in contact with the surface to be cleaned in the central region C, and an appropriate amount for wiping is discharged. Further, the cleaning liquid is not unnecessarily discharged to the surface side of the wiping sheet 1 that is not in contact with the surface to be cleaned, that is, the manual or cleaning tool 220 side. As a result, the wiping sheet of the present invention has excellent sustained release properties of the cleaning liquid and excellent dirt collection and removal performance. Further, since the wiping sheet 1 has a central area C and a side area S, the wiping sheet 1 can be easily attached to the cleaning tool 220 by the side area S while carrying the cleaning liquid in the side area S as well. In addition, the central region C allows wiping with the above-mentioned advantages. In addition to this, the second fiber layer L2 containing the large-diameter fibers 12 and having many voids can reduce the contact area between the wiping sheet and the surface to be cleaned, so that the frictional resistance between the wiping sheet and the surface to be cleaned can be reduced. There is also an advantage that the operability at the time of use can be improved.

4 to 7 show another embodiment of the wiping sheet 1. The embodiments described below will be described focusing on points different from the above-described embodiments, and the above-described description of the embodiments will be appropriately applied to points not particularly described. The same points as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The wiping sheet 1 shown in FIGS. 4 and 5 (a) and 5 (b) is composed of a fiber assembly 1A in which at least the central region C contains hydrophilic fibers 11, large-diameter fibers 12, and small-diameter fibers 13. Specifically, as shown in the figure, the wiping sheet 1 includes a first fiber layer L1 containing hydrophilic fibers 11 and a large-diameter fiber 12 in the central region C thereof, and each surface of the first fiber layer L1. A third fiber containing a second fiber layer L2 arranged adjacent to the above and a small diameter fiber 13, and arranged adjacent to the side of the second fiber layer L2 on which the first fiber layer L1 is not arranged. It has a layer L3. These fiber layers L1, L2, and L3 are integrated to form a fiber assembly 1A. Each of the fiber layers L1, L2, and L3 in the present embodiment is arranged over the entire area of the wiping sheet 1 in a plan view.

As shown in FIGS. 4 and 5 (a) and 5 (b), the first surface 1F of the wiping sheet 1 is formed by the surface of the third fiber layer L3 on the side where the second fiber layer L2 does not exist. The two surfaces 1R are formed by the surfaces of the second fiber layer L2 on the side where the first fiber layer and the third fiber layer L3 are not arranged. Further, no other fiber layer is arranged on the second surface 1R. Therefore, in the present embodiment, the small-diameter fibers 13 are mainly present on the first surface 1F, and the large-diameter fibers 12 are mainly present on the second surface 1R. In the present embodiment, the first surface 1F on which the third fiber layer L3 is arranged is preferably used as the wiping surface.

In each of the fiber layers L1, L2, and L3 constituting the wiping sheet 1, the boundary surface of each fiber layer may be clearly present as in the above-described embodiment, and the boundary surface of each fiber layer may be present. It may be obscured and exist. In any case, when the wiping sheet 1 is viewed along the thickness direction Z, the abundance ratio of the constituent fibers in each fiber layer changes stepwise, continuously, or in a combination thereof. Is preferable.

Further, as in the above-described embodiment, when the boundary surface of each fiber layer is unclear, the fibers constituting one fiber layer invade the other fiber layer beyond the boundary surface of the adjacent layer. It is also preferable to have. As such a specific example, as shown in FIG. 6, an embodiment in which the hydrophilic fiber 11 penetrates the second fiber layer L2 side beyond the interface between the first fiber layer L1 and the second fiber layer L2. , And the large-diameter fiber 12 invades the first fiber layer L1 side beyond the interface between the first fiber layer L1 and the second fiber layer L2, or as shown in FIG. 7A. Examples thereof include a mode in which the large-diameter fiber 12 penetrates the third fiber layer L3 side beyond the boundary surface between the second fiber layer L2 and the third fiber layer L3, and a combination thereof. The hydrophilic fibers 11 constituting the first fiber layer L1 further penetrate the third fiber layer L3 side beyond the second fiber layer L2, and the small diameter fibers 13 constituting the third fiber layer L3 are the first. It is not prevented that the fibers that have penetrated the first fiber layer L1 side beyond the two fiber layers L2 are further invaded, or that the fibers that have invaded the other fiber layers are exposed on the outer surface of the sheet.

In particular, in the wiping sheet 1, as shown in FIGS. 7A and 7B, the large-diameter fibers 12 cross the boundary surface between the second fiber layer L2 and the third fiber layer L3 and are on the third fiber layer L3 side. It is preferable that at least the tip portions of the small-diameter fibers 13 and the large-diameter fibers 12 are present on the first surface 1F, which is the surface of the third fiber layer L3. With such a configuration, the high-rigidity large-diameter fiber 12 scrapes off the dirt adhering to the surface to be cleaned to lift the dirt, and the third fiber layer L3 made of the small-diameter fiber is dense and dense. With a structure having a low porosity, dirt can be efficiently collected and retained, and as a result, the dirt collecting property is further improved.

From the viewpoint of exhibiting sufficient scraping property against dirt existing on the surface to be cleaned, the number of large-diameter fibers 12 existing on the first surface 1F of the wiping sheet 1 is preferably 20 fibers / cm ² or more, and further. It is preferably 50 lines / cm ² or more, preferably 4000 lines / cm ² or less, and more preferably 2000 lines / cm ² or less. ^{The number of large-diameter fibers 12 existing on the first surface 1F is the total mass (g / cm 2} ) per unit area of the wiping sheet 1 on the first surface 1F, and the mass of the large-diameter fibers 12 per fiber. It can be a value divided by (g).

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

From the viewpoint of further enhancing the collectability of dirt, the fiber diameter D3 of the small diameter fiber 13 is preferably 2 μm or less, more preferably 1.8 μm or less, and 0.1 μm or more is realistic. The fiber diameter D3 of the small diameter fiber 13 can be measured by, for example, the method described above. Such a small diameter fiber 13 can be obtained by a method such as a melt blown method or an electric field spinning method, and the fiber obtained by the method is generally a long fiber.

Further, from the viewpoint of making it easier for the cleaning liquid existing in the first fiber layer L1 to be drawn into the third fiber layer L3 side by the capillary force and improving the usage efficiency of the supported cleaning liquid, the hydrophilic fiber 11 has a smaller diameter than the fiber diameter D1. The ratio (D3 / D1) of the fiber diameter D3 of the fiber 13 is preferably 0.008 or more, more preferably 0.010 or more, preferably 0.08 or less, still more preferably 0.06 or less.

As described above, the wiping sheet 1 further including the third fiber layer L3 containing the small diameter fibers 13 has a higher capillary force in the third fiber layer L3 than the other fiber layers, so that the first fiber layer L1 and the first fiber layer L3 The cleaning liquid held in the 2nd fiber layer L2 can be easily drawn into the 3rd fiber layer L3 side. As a result, a sufficient amount of cleaning liquid for removing dirt can be continuously and continuously supplied to the surface to be cleaned, and the liquid is excellent in sustained release property. In addition to this, by wiping the third fiber layer L3, which has a dense and low porosity structure, in contact with the surface to be cleaned, the dirt collection performance and the dirt retention performance can be improved, so that dirt can be removed. Collectability is further improved.

In particular, according to a preferred embodiment of the wiping sheet further including the third fiber layer L3, both the large-diameter fibers 12 and the small-diameter fibers 13 are exposed on the first surface 1F, so that the first surface 1F and the cleaning sheet are present. When the surface to be cleaned is brought into contact with the surface and wiped, the high-rigidity large-diameter fibers 12 can scrape the dirt existing on the surface to be cleaned, and the scraped dirt can be collected and held by the third fiber layer L3. Therefore, the collecting property of dirt, particularly the collecting property of fine particle dirt such as dust and sand dust is further improved. Further, since the frictional resistance between the wiping sheet and the surface to be cleaned can be further reduced as compared with the case where only the small diameter fibers come into contact with the surface to be cleaned, the operability during use can be further improved. There is also an advantage.

8 and 9 (a) and 9 (b) show still another embodiment of the wiping sheet 1. In the embodiment shown in the figure, 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. 8 and 9 (a) and 9 (b), a region in which the second fiber layer L2 exists between the first fiber layer L1 and the third fiber layer L3 in the sheet surface direction. Region R2 where the second fiber layer L2 does not exist between R1 (hereinafter, this is also referred to as “existing region R1”) and the first fiber layer L1 and the third fiber layer L3 (hereinafter, this is “non-existent”). It is preferable that the region R2) is formed at least in the central region C. The non-existing region R2 shown in the figure is formed in a plurality of strip-shaped regions in which the existing region R1 and the non-existing region R2 are alternately formed so as to extend in one direction. Instead of this, the non-existing region R2 may be formed in a scattered pattern in the direction of the seat surface. As shown in FIG. 8, the first fiber layer L1, the second fiber layer L2 located on the second surface 1R side, and the third fiber layer L3 are arranged in the entire area in the central region C in the sheet surface direction.

In particular, in the non-existent 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 entangled. It is also preferable to have. In the embodiments shown in FIGS. 8 and 9 (a) and 9 (b), the hydrophilic fibers 11 constituting the first fiber layer L1 and the small diameter fibers 13 forming the third fiber layer L3 are formed in the non-existent region R2. Is directly fused or entangled with. With such a configuration, the collectability of dirt can be further improved in the existing region R1. Further, since the cleaning liquid held in the first fiber layer L1 can be directly drawn to the third fiber layer L3 side, the cleaning liquid can be continuously and continuously supplied to the surface to be cleaned, and the sustained release property of the liquid further increases. Excellent. Further, since the utilization efficiency of the supported cleaning liquid can be further improved, it is possible to wipe a wider area with one wiping sheet.

In each of the above-described embodiments, from the viewpoint of improving the dirt scraping property and entanglement property and further enhancing the dirt collecting property, FIGS. 5 (b), 7 (a) and (b), and FIG. 9 As shown in (b), the large-diameter fiber 12 contained in at least one of the two second fiber layers L2 is preferably a crimped fiber, and the large-diameter fiber 12 contained in both the second fiber layers L2 is It is more preferably crimped fiber. Further, the crimp fibers are preferably present at least on the wiping surface side, and are preferably exposed on the sheet surface. The crimped fiber is a fiber having a spiral, zigzag, U-shaped or a combination thereof in the form of crimping. When the large-diameter fiber 12 is a crimped fiber, the large-diameter fiber 12 is also referred to as the above-mentioned composite fiber or a fiber capable of exhibiting spiral crimping by applying heat (hereinafter, this is also referred to as a latent crimped fiber. ) Can be preferably used. Since the large-diameter fiber 12 is a crimped fiber, the second fiber layer L2 acts like a spring when the wiping sheet 1 is pressed against the surface to be cleaned, so that the wiping sheet 1 is 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 utilization efficiency of the liquid and the sustained release property are further improved.

When the large-diameter fiber 12 is a crimped fiber, the number of crimped fibers is preferably 1 or more, more preferably 2 or more, and further preferably 2 or more, from the viewpoint of further enhancing the dirt collecting performance. The upper limit is preferably 10 or less, and more preferably 8 or less. The number of crimped fibers can be measured according to the method described in JIS L 1015. When the crimped fibers are present in each of the second fiber layers L2, the above-mentioned number of crimped fibers may be satisfied independently in each of the second fiber layers L2.

Synthetic fibers containing the above-mentioned components and eccentric core-sheath type or side-by-side type composite fibers are preferably used as the constituent components of the large-diameter fiber 12, from the viewpoint of further enhancing 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. When the eccentric core sheath type composite fiber is used, it is also preferable to use PET as a core and co-PET or PE as a sheath. In particular, the composite fiber composed of such a component causes crimping on the large-diameter fiber 12 to scrape or entangle dirt from the surface to be cleaned to further improve the dirt collecting performance. Is advantageous.

The basis weight of the fiber aggregate constituting the wiping sheet in the dry state of the fiber aggregate, preferably 50 g / ^{m 2} or more, more preferably 55 g / ^{m 2} or more, more preferably 60 g / ^{m 2} or more, It is preferably 420 g / m ² or less, more preferably 410 g / m ² or less, and further preferably 400 g / m ² or less. By having such a configuration, the amount of the cleaning liquid supported is increased, and the liquid is sustained release, operability during use, and dirt collection. In addition to this, there is an advantage that the strength that can withstand the actual use of the wiping sheet can be developed. The 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 on which the cleaning liquid is carried, the carried water may be removed until the above-mentioned water content is reached by using a known dryer, centrifuge or the like.

The basis weight of the first fibrous layer L1 constituting the wiping sheet in the dry state of the fiber aggregate, preferably 20 g / ^{m 2} or more, more preferably 25 g / ^{m 2} or more, more preferably be 30 g / ^{m 2} or more Further, it is preferably 220 g / m ² or less, more preferably 210 g / m ² or less, and further preferably 200 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 10 g / m ² or more, more preferably 15 g / m ² or more, still more preferably 20 g / m 2 or more independently in the dry state of the fiber aggregate. It is m ² or more, preferably 115 g / m ² or less, more preferably 110 g / m ² or less, and further preferably 105 g / m ² or less. With such a configuration, the dirt scraping property due to the high rigidity of the large-diameter fiber is improved, and the dirt collecting property is further improved.

When the third fiber layer L3 is further provided, 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 in the dry state of the fiber aggregate. It is more preferably 25 g / m ² or more, preferably 50 g / m ² or less, more preferably 48 g / m ² or less, still more preferably 45 g / m ² or less. With such a configuration, the aggregate of the small-diameter fibers has a structure having a low porosity, so that dirt can be efficiently collected and retained, and the dirt collecting property is further improved.

As long as the effects of the present invention are exhibited, the first fiber layer L1 constituting the wiping sheet 1 may be composed of only the hydrophilic fibers 11, and in addition to this, other synthetic fibers and the like described above may be used. It may further contain fibers. Similarly, the second fiber layer L2 may be composed of only the large-diameter fibers 12, and may further contain other fibers such as the above-mentioned cellulose fibers and synthetic fibers. Similarly, when the third fiber layer L3 is further provided, the third fiber layer L3 may be composed of only the small diameter fibers 13, and in addition to this, other other fibers such as the cellulose fibers and synthetic fibers described above may be provided. It may further contain fibers. These can be used alone or in combination of two or more. The other fibers that can be contained in each fiber layer may have a circular (non-deformed) cross section or a non-circular (non-deformed) 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, by using a synthetic fiber containing a thermosetting resin as another fiber, the constituent fibers can be fused to each other by applying heat, and the strength of the entire sheet can be exhibited with high strength, which is preferable.

From the viewpoint of ensuring sufficient strength when the wiping sheet 1 is used, the thickness of the wiping sheet 1 is preferably 0.5 mm or more, preferably 0.8 mm or more, in a ^{dry state and under a load of 40 N / m 2.} It is more preferably 11.0 mm or less, and further preferably 10.0 mm or less under the same load.

The above is the description of the wiping sheet of the present invention. Hereinafter, taking the wiping sheet having a four-layer structure shown in FIG. 4 as an example, a suitable manufacturing method of the sheet will be described with reference to FIGS. 10 and 11. To do. 10 and 11 show a manufacturing apparatus 100 suitably used for manufacturing the wiping sheet 1 having a four-layer structure shown in FIG. In this production method, a step of laminating a fiber layer containing a hydrophilic fiber 11 on an upper surface of a fiber layer containing a large-diameter fiber 12 to form a first laminated body S1 (first laminating step) and a step of laminating the hydrophilic fiber 11 A step of further laminating a fiber layer containing a large-diameter fiber 12 on the upper surface of the containing fiber layer to form a second laminated body S2 (second laminating step), and a step of further laminating the fine-diameter fiber 13 on the upper surface of the second laminated body S2. It is roughly divided into a step of laminating the fiber layers to form the third laminated body S3 (third laminating step) and a step of integrating the laminated bodies (integration step).

The manufacturing apparatus 100 shown in FIGS. 10 and 11 is provided with a breathable transport belt 110 made of an endless belt. The transport belt 110 is provided with two transport rolls 111 and 111 so as to draw an orbit in a single direction (convey direction MD). Above the transport belt 110, a first forming portion 120 in which a second fiber layer L2 containing a large-diameter fiber 12 is laminated and formed, and a first fiber layer L1 containing a hydrophilic fiber 11 are placed on the upper surface of the second fiber layer L2. A second forming portion 130 to be laminated, a third forming portion 140 in which a second fiber layer L2 containing a large diameter fiber 12 is laminated on the upper surface of the first fiber layer L1, and a third fiber layer containing a small diameter fiber 13. A fourth forming portion 145 for laminating and forming L3 on the upper surface of the second fiber layer L2 is provided. By passing through the forming portions 120, 130, 140, and 145 in this order, the third laminated body S3 can be formed through the formation of the first laminated body S1 and the second laminated body S2.

Further, on the lower surface side of the first laminated body S1 and the second laminated body S2 at positions facing each of the forming portions 120, 130, 140, the above-mentioned fiber layer is attracted to the transport belt side and the first laminated body is formed. A suction box 150 for forming the body S1 and the second laminated body S2 is provided. As described above, the present manufacturing apparatus has the same configuration as the manufacturing apparatus used in the general airlaid method.

The fourth forming portion 145 in the present embodiment is in the form of a raw fabric roll, and the third fiber layer L3 containing the small diameter fibers 13 is fed out as a long strip-shaped sheet, and the second laminated body S2 has a second. It can be laminated on the upper surface of the fiber layer L2.

On the downstream side of each of the forming portions 120, 130, 140, 145 in the transport direction MD, an integration processing device 160 for integrating each fiber layer in the third laminated body S3 is provided. The integrated processing device 160 shown in FIG. 10 is an embodiment of a water flow confounding device that integrates a laminated body by spraying a high-pressure water flow. In the present embodiment, a support belt 161 composed of endless belts spanning a pair of support rolls 162 and allowing water to permeate is provided at a position facing the integrated processing device 160, and the integrated processing device 160 is provided. A high-pressure water stream is sprayed onto the third fiber layer L3 located on the upper surface side of the third laminated body S3 introduced between the and the support belt 161 so that the constituent fibers can be entangled and integrated.

The integrated processing device 160 shown in FIG. 11 is an embodiment of a heating device that heats and integrates the third laminated body S3. The integrated processing device 160 is capable of transporting the third laminated body S3 inside the integrated processing device 160 to heat the third laminated body S3. Examples of the heating mode of the third laminated body S3 in the integrated processing apparatus 160 include a heater, spraying of heated gas, infrared irradiation, and the like, and spraying of heated gas is preferable. In the present embodiment, when the latent crimped fiber is used as the large diameter fiber 12, the second laminated body S2 is integrated by heating, and the latent crimped fiber is crimped by applying heat to the crimped fiber. The large-diameter fiber 12 can be used.

A suitable manufacturing method of the wiping sheet using the manufacturing apparatus 100 shown in FIGS. 10 and 11 is as follows. First, the fiber layer containing the hydrophilic fibers 11 is laminated on the upper surface of the fiber layer containing the large-diameter fibers 12 to form the first laminated body S1 (first laminating step). Specifically, the large-diameter fibers 12 and, if necessary, other fibers are supplied from the first forming portion 120 so as to be uniform in the belt surface direction, and the first fiber layer L1 is supplied to the transport belt 110. Form on top. After that, the hydrophilic fiber 11 and other fibers such as synthetic fibers are supplied from the second forming portion 130, and the first fiber layer L1 is laminated on the second fiber layer L2, and the first fiber layer L1 is laminated on the second fiber layer L2. 1 Laminated body S1 is formed.

Next, the large-diameter fibers 12 and other fibers are supplied from the third forming portion 140, and the second fiber layer L2 is laminated on the first fiber layer L1 to form a third layer structure. 2 Laminated body S2 is formed (second laminating step). In forming the second laminated body S2 by the third forming portion 140, when the second fiber layer L2 is formed over the entire surface direction of the target wiping sheet 1, the large-diameter fibers are formed over the entire surface direction of the first fiber layer L1. The constituent fibers such as 12 may be supplied and used in the next step. Further, in order to form the non-existing region R2 on the target wiping sheet 1, for example, in the plane direction of the first fiber layer L1, a portion to which the constituent fibers such as the large diameter fiber 12 are supplied and the large diameter fiber A portion such as 12 to which the constituent fibers are not supplied may be formed and used in the next step. In this case, the portion to which the constituent fibers such as the large diameter fibers 12 are supplied becomes the existing region R1 in the wiping sheet 1, and the portion to which the constituent fibers such as the large diameter fibers 12 are not supplied becomes the non-existing region R2.

Next, the third fiber layer L3 made of a fiber sheet containing the fine diameter fibers 13 is supplied from the fourth forming portion 145, and the third fiber layer L3 is laminated on the second fiber layer L2 to form a four-layer structure. The third laminated body S3 is formed (third laminated step).

Subsequently, each fiber layer in the third laminated body S3 is integrated by water flow entanglement or heating (integration step). As shown in FIG. 10, when the integrated processing device 160 is an aspect of a water flow confounding device, the high-pressure water flow ejected from the integrated processing device 160 while the third laminated body S3 is conveyed in the MD direction by the support belt 161. Is entangled by. By going through this step, the fibers of the third laminated body S3 are entangled with each other to form the fiber aggregate 1A.

When the integrated processing device 160 is an embodiment of a water flow confounding device, the water pressure sprayed on the third laminated body S3 is preferably 30 kg / cm ² or more, more preferably 40 kg / cm ² or more, and preferably 80 kg / cm /. It is cm ² or less, more preferably 60 kg / cm ² or less. The transport speed of the third laminated body S3 in the MD direction is preferably 2 m / min or more, more preferably 4 m / min or more, preferably 10 m / min or less, still more preferably 8 m / min or less. Can be manufactured.

As shown in FIG. 11, when the integrated processing device 160 is a heating device, the second fiber layer L2 and the third fiber layer L3 are formed by spraying a heating gas preferably on the third laminated body S3. A part of the constituent fibers is melted, and the fibers constituting the third laminated body S3 are fused and integrated. In addition to this, when the first fiber layer L1 contains other fibers such as synthetic fibers containing a thermosetting resin, the thermosetting resin contained in the other fibers is melted by applying heat. Due to this, the hydrophilic fibers 11 are further fused and integrated. At the same time, when the latent crimp fiber is used as the large diameter fiber 12, the crimp is developed by applying heat, and the fiber becomes a crimp fiber.

The heating temperature in the heating device can be appropriately adjusted depending on the raw material of the constituent fibers, the melting point, and the like, but is preferably 130 ° C. or higher, more preferably 140 ° C. or higher, and preferably 200 ° C. or lower, further preferably 180 ° C. It is below ° C. Further, the heat treatment time in the heating step can be preferably 10 seconds or more and 100 seconds or less in the above temperature range. ^{When spraying the 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, and more preferably 550 m 3 / min or more, provided that the flow rate of the heated gas is within the above-mentioned temperature and heating time range. It is preferably 4600 m ³ / min or less, and ^{more preferably 4500 m 3} / min or less.

Specifically, the first fiber layer L1 containing pulp fibers as hydrophilic fibers 11 and PET fibers as other fibers, and eccentricity in which PET is a core and co-PET is a sheath as large-diameter fibers 12. Heated gas with respect to the third laminated body S3 forming the two second fiber layers L2 containing latent crimp fibers which are core-sheath type composite fibers and the third fiber layer L3 containing polypropylene fibers as the small diameter fibers 13. When spraying, the heated gas at 150 ° C. or higher and 170 ° C. or lower ^{can be sprayed at a flow rate of 2000 m 3} / min or more and 2500 m ³ / min or less with a heat treatment time of 20 seconds or more and 80 seconds or less.

Through the above steps, a fiber aggregate 1A having a four-layer structure 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 treatment by heat embossing or ultrasonic embossing can be further performed. Further, the above-mentioned heat treatment and fusion treatment may be further performed on the fiber aggregate 1A that has undergone water flow entanglement.

As shown in FIG. 2, when forming a fiber aggregate 1A having a three-layer structure having a first fiber layer L1 and two second fiber layers L2, a first laminating step and a second laminating step are performed. After forming the second laminated body S2, the second laminated body S2 may be directly subjected to the integration step without performing the third laminating step by the fourth forming portion 145. That is, the first laminating step, the second laminating step, and the integrating step may be performed in this order. In this case, from the viewpoint of strengthening the integration of each fiber layer, it is preferable to integrate them by heat treatment, and the first fiber layer L1 is composed of the hydrophilic fiber 11 and other fibers containing a thermosetting resin. It is preferable to configure it so as to include.

In the manufacturing process of the wiping sheet 1, as the large-diameter fiber 12, a fiber that does not develop crimping may be used, a crimped fiber that has developed crimping in advance may be used, or a latent crimped fiber may be used. You may use it. In particular, in order to produce a wiping sheet containing crimped fibers as the large-diameter fibers 12, when the integration treatment is performed by water flow confounding, crimped fibers that have been crimped in advance can be used. Further, the large-diameter fiber 12 contained in one of the second fiber layers L2 was defined as a fiber in which crimping was not exhibited, and the large-diameter fiber 12 contained in the other second fiber layer L2 was designated as a fiber in which crimping was exhibited. When the wiping sheet is manufactured, the fibers laminated in the first forming portion 120 and the third forming portion 140 may be different from each other.

In order to make the composition of the fiber layer in the central region C different from the configuration of the fiber layer in the side region S, for example, the supply width of the fibers supplied from the first forming portion 120 and the third forming portion 140 Alternatively, the width of the fiber sheet supplied from the fourth forming portion 145 may be adjusted by increasing or decreasing as appropriate. In particular, such a manufacturing method has an advantage that the manufacturing cost can be reduced because it is not necessary to supply the constituent raw materials of each fiber layer to the side region S, which is less likely to contribute to wiping than the central region C.

The fiber aggregate 1A produced 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 of supporting the cleaning liquid in the supporting step, for example, the fiber aggregate 1A may be immersed in the cleaning liquid, or the cleaning liquid may be sprayed on the fiber aggregate 1A. In order to support the cleaning liquid on at least the first fiber layer L1, for example, the fiber aggregate 1A may be immersed in the cleaning liquid.

In loading step, loading of the cleaning solution to be 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, more preferably 1600 g / ^{m 2} or less .. In other words, the carrying ratio of the cleaning liquid to the mass of the dried fiber aggregate 1A is preferably 300% by mass or more, more preferably 350% by mass or more, and preferably 550% by mass or less, more preferably 550% by mass or less, as a mass percentage. Is 500% by mass or less.

Further, before or after the cleaning liquid is supported on the fiber assembly 1A, or at the same time as the cleaning liquid is supported, the fiber assembly 1A can be folded back at a predetermined position to form a bending line FL (bending step, not shown). ). The fiber aggregate 1A folded back at a predetermined position can be used as a wet wiping sheet and then distributed on the market as a package in which a plurality of the sheets are laminated and housed in a packaging bag. The folding line FL can be formed, for example, at the boundary between the central region C and the lateral region S, respectively.

The wet wiping sheet produced in this manner can be attached to a cleaning tool having a structure as shown in FIG. 1 by itself or preferably on a floor surface, a wall surface, or the like, whether outdoors or indoors. For cleaning and cleaning of buildings, cupboards, windowpanes, mirrors, doors, doorknobs and other fittings, rugs, carpets, furniture such as desks and dining tables, kitchens, toilets, bodies, etc., sanitary goods, packaging, etc. Can be used.

Although the present invention has been described above based on the preferred embodiment, the present invention is not limited to the above embodiment. For example, the third fiber layer L3 used in the manufacturing method has been described as an embodiment of a fiber sheet containing the small diameter fibers 13, but the present invention is not limited to this form. For example, the small diameter fiber 13 may be directly spun at a position where the central region C is to be formed on the second laminated body S2 by a melt blown method, an electric field spinning method, or the like to form the third fiber layer L3. After that, a wet wiping sheet can be manufactured by performing an integration step and a supporting step.

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

[Example 1]
Pulp having an average fiber diameter of 12 μm was used as the hydrophilic fiber 11. As the large-diameter fiber 12, an eccentric core-sheath type fiber having an average fiber diameter of 44 μm having PET as a core and co-PET as a sheath was used. A first fiber layer L1 made of a mixed cotton body containing hydrophilic fiber 11 (pulp) PET fiber = 4.0: 6.0 and having an average fiber diameter of 11.4 μm, and the fiber layer L1. Two second fiber layers L2 made of large diameter fibers 12 were formed on each surface of the above. 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 . These fiber layers were integrated by the airlaid method to obtain a fiber aggregate 1A having a three-layer structure ^{having a basis weight of 260 g / m 2.}

The fiber layers L1 and L2 in this example were formed in the entire area in the central region C in the sheet surface direction. Further, the large-diameter fibers 12 existing in both second fiber layers L2 are all crimped fibers, and the hydrophilic fibers 11 cross the boundary surface between the first fiber layer L1 and the second fiber layer L2 and are the second fibers. It penetrated the layer L2 side, and both the hydrophilic fiber 11 and the large-diameter fiber 12 were present on each surface of the second fiber layer L2.

Next, the above-mentioned fiber assembly 1A was impregnated with a cleaning liquid to produce a wet wiping sheet composed of the fiber structure having a three-layer structure shown in FIG. The cleaning liquid was impregnated so as to support at least the first fiber layer L1. The impregnation amount of the cleaning liquid was 400% by mass as a mass ratio to the mass of the dry fiber aggregate 1A. The composition of the washing liquid was an aqueous solution containing 0.3% by mass of polyoxyethylene lauryl ether. The wiping sheet was rectangular and had dimensions of 285 mm x 205 mm.

[Example 2]
A third fiber layer L3 using PP fibers having an average fiber diameter of 1 μm as the fine diameter fibers 13 is further laminated on one surface of the second fiber layer L2, and the fiber layers are integrated by the spunlace method to aggregate the fibers. A wet wiping sheet having a four-layer structure in which the central region C is shown in FIG. 8 was obtained in the same manner as in Example 1 except that the body 1A was obtained. The basis weight of the third fiber layer L3 was 30 g / m ^2, and the basis weight of the fiber assembly 1A was 290 g / m ² . In the wet wiping sheet of this example, the non-existing region R2 was formed.

[Comparative Example 1]
A wet wiping sheet including a fiber aggregate composed of a fiber web and a net-like sheet was produced according to the method described in JP-A-2007-154359. The fiber web contained a mass ratio of rayon: acrylic fiber: PET fiber = 25:25:50 and had a ^{basis weight of 60 g / m 2.} The net-like 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 washing liquid of 400% by mass as a mass ratio to the mass of the dry fiber aggregate. 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 had dimensions of 285 mm x 205 mm.

[Evaluation 1: Evaluation of sustained release of cleaning solution]
A rectangular tile floor (manufactured by LIXIL Corporation, Charlotte II) having a dimension of 0.6 m × 0.6 m per sheet by applying a load of ^{0.16 kN / m 2} to the wet wiping sheets of Examples and Comparative Examples. 36 sheets ( ^{equivalent to 12.96 m 2} ) were wiped as the surface to be cleaned. Wiping was performed over the entire surface to be cleaned by moving the sheet four times in a range equivalent to a half tatami mat (0.9 m × 0.9 m) at a wiping speed of 1 m / s. Based on the initial carrying amount (g) of the cleaning liquid on the wiping sheet used, the amount of the cleaning liquid released to the tile floor by wiping (g) and the residual amount of the cleaning liquid remaining on the wiping sheet (g) are one. The area equivalent to tatami mats (1.8 m × 0.9 m) was measured every time the wiping was performed, and the sustained release property of the cleaning liquid was evaluated. In addition, the percentage of the residual amount (g) of the cleaning liquid after the completion of wiping (after wiping 36 tile floors) with respect to the initial loading amount (g) of the cleaning liquid was calculated, and the utilization efficiency of the cleaning liquid was evaluated. The results are shown in FIG. In the graph shown in FIG. 12, 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 FIG. 12, the wet wiping sheet of the example has a higher amount of the cleaning liquid supported than the wet wiping sheet of the comparative example, the wet state of the wiping sheet is maintained for a long time, and the cleaning liquid is gradually added. It can be seen that the release property is good. In particular, in Example 2 in which the third fiber layer L3 is further provided, the amount of the cleaning liquid supported is further increased, and the cleaning liquid is continuously released in a large amount from the start to the end of wiping. Therefore, from the start to the end of wiping. It can also be seen that the cleaning solution is particularly excellent in sustained release, and that a large area can be wiped with a single wiping sheet.

[Evaluation 2: Evaluation of dirt collection property]
Using the wiping sheets of Example 1 and Comparative Example 1, the outdoor concrete floor to which dust and sand had adhered was wiped as the surface to be cleaned, and the dirt collection performance was evaluated. Wiping in this evaluation is performed by placing a weight with a mass of 1.5 kg and a plane dimension of 50 mm × 80 mm (load: ^{equivalent to 3.75 kN / m 2} ) on a wiping sheet and reciprocating within a range of 15 cm three times in the front-rear direction. It was. The results are shown in FIG.

As shown in FIG. 13, the wiping sheet of the example can be wiped without peeling or breaking of fibers after wiping as compared with the wiping sheet of the comparative example, and stains adhering to the surface to be cleaned can be removed. It can be seen that dirt can be collected and retained on the sheet by scraping.

1 Wet wiping sheet 1A Fiber assembly 1F 1st surface 1R 2nd surface 11 Hydrophilic fiber 12 Large diameter fiber 13 Small diameter fiber L1 1st fiber layer L2 2nd fiber layer L3 3rd fiber layer C Central area S Side area Z Thickness direction 100 Manufacturing equipment 200 Cleaning tool

Claims (7)

A wet wiping sheet having a central region extending in one direction and a pair of lateral regions extending in one direction adjacent to the central region in a plan view.
In the wet wiping sheet, the central region is located on the lower surface of the head portion of a cleaning tool having a head portion having a fixed portion of the wet wiping sheet on the upper surface, and the lateral region is formed by the fixing portion on the upper surface. It is used by being attached to the head portion so as to be fixed.
The central region has a first fiber layer containing hydrophilic fibers and a second fiber layer containing thick fibers having a fiber diameter of 30 μm or more adjacent to each surface of the first fiber layer.
A wet wiping sheet on which a cleaning liquid is supported. The wet wiping sheet according to claim 1, further comprising a third fiber layer including fine-diameter fibers having a fiber diameter of 2 μm or less, which is adjacent to the side of the second fiber layer where the first fiber layer is not arranged. The large-diameter fiber has penetrated into the third fiber layer side beyond the boundary surface between the second fiber layer and the third fiber layer.
The wet wiping sheet according to claim 2, wherein the large-diameter fibers and the small-diameter fibers are present on the surface of the third fiber layer. A region where the second fiber layer does not exist is formed between the first fiber layer and the third fiber layer.
The wet wiping sheet according to claim 2 or 3, wherein the region is a direct fusion or entanglement of the fibers constituting the first fiber layer and the fibers constituting the third fiber layer. The wet wiping sheet according to any one of claims 2 to 4, wherein the basis weight of the third fiber layer is 20 g / m ² or more and 50 g / m ^{2 or less.} The wet wiping sheet according to any one of claims 1 to 5, wherein the large-diameter fiber is a crimped fiber. The wet wiping sheet according to any one of claims 1 to 6, wherein the large-diameter fiber is a composite fiber of polyethylene terephthalate and polyethylene.

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