JP7359677B2 - 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 is replaced less often even if the wiping area is large. There was room for improvement. Further, the nonwoven fabrics and sheets of Patent Documents 2 and 3 do not have a high level of sustained liquid release properties and dirt collection properties. Furthermore, the sheets described in each of the patent documents have not been examined for sustained release of liquid when used by being attached to a cleaning tool, and there is still room for improvement in this respect as well.

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

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

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

FIG. 1(a) is a schematic perspective view of an embodiment of the wet wiping sheet of the present invention and a preferred mode of use as seen from the bottom side, and FIG. 1(b) is a schematic perspective view of the wet wiping sheet of the present invention. FIG. 2 is a schematic perspective view showing an embodiment in which the cleaning tool is 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. 3(a) is an embodiment of a schematic cross-sectional view taken along the II plane of the wet wiping sheet shown in FIG. 2, and FIG. 3(b) is another schematic cross-sectional view taken along the II plane This is an embodiment. 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 taken along the II-II plane of the wet wiping sheet shown in FIG. This is an embodiment. FIG. 6 is an enlarged image observed with a scanning electron microscope showing the laminated state of the first to third fiber layers in the thickness direction cross section of the wet wiping sheet. FIG. 7(a) is another enlarged observation image showing the stacked state of the second and third fiber layers in the thickness direction cross section of the wet wiping sheet, and FIG. 7(b) is the same as that shown in FIG. 7(a). This is an observation image of the first surface of the wet wiping sheet using a scanning electron microscope. FIG. 8 is a schematic perspective view showing still another embodiment of the wet wiping sheet of the present invention. FIG. 9(a) is an embodiment of a schematic cross-sectional view of the wet wiping sheet shown in FIG. This is an embodiment. FIG. 10 is a schematic diagram showing an embodiment of a manufacturing apparatus suitably used for manufacturing the wet wiping sheet of the present invention. FIG. 11 is a schematic diagram showing another embodiment of a manufacturing apparatus suitably used for manufacturing the wet wiping sheet of the present invention. FIG. 12 is a graph showing the relationship between the amount of cleaning liquid retained and the amount released when wet wiping sheets of Examples and Comparative Examples are used. FIG. 13 is a photograph showing the dirt collection performance when 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 of the surface of the object to be cleaned, and includes, for example, cleaning of floors, walls, ceilings, pillars, etc. of buildings, and cleaning of fittings and fixtures. This includes wiping down items, cleaning the body and 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.

FIGS. 1(a) and 1(b) show an embodiment of the wet wiping sheet of the present invention and a preferred usage pattern. The wet wiping sheet 1 (hereinafter also simply referred to as "wiping sheet 1") shown in FIGS. C, and a pair of side regions S, S adjacent to this and extending in the same direction as the central region C. The central region C and the side regions 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. Moreover, 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 this embodiment, the first surface 1F and the second surface 1R, which are the surfaces of the second fiber layer L1, can be used as wiping surfaces that are used in contact with the surface to be cleaned when the wiping sheet 1 is used. The wiping sheet 1 shown in FIGS. 1(a) and 1(b) has a first surface 1F used as a wiping surface.

As shown in FIGS. 1A and 1B, the wiping sheet 1 is preferably used as an embodiment of a cleaning tool 200 attached to a cleaning tool 220. A 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 section 210 is a rectangular member, and a plurality of fixing sections 211 for fixing the wiping sheet 1 are provided on the upper surface 210A of the head section 210. The head section 210 is configured such that the second surface 1R of the wiping sheet 1 and the lower surface 210B of the head section 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 is extendable or extendable by assembly, a member that has a handle, or a member that is a combination thereof.

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 section 210 coincide with each other. Therefore, when attaching the wiping sheet 1 to the cleaning tool 220, it is necessary to attach the wiping sheet 1 so that the central region C is located on the lower surface 210B of the head part and the first surface 1F faces the surface to be cleaned. It is preferable in that it improves the collection performance. In this case, the pair of side regions S, S become regions extending from the side edges of the head portion 210, so each side region S is folded back along the bending line FL or its vicinity, and each side region It is attached to the head part 210 so that the areas S, S are fixed by the fixing part 211.

The wiping sheet 1 includes a fiber aggregate including a plurality of fiber layers in its central region C. Specifically, the central region C of the wiping sheet 1 includes a first fiber layer containing hydrophilic fibers and 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"). ), the second fiber layer being disposed adjacent to each side of the first fiber layer. In addition, in the central region C on one surface of the wiping sheet 1, third fibers containing thin fibers having a fiber diameter of preferably 2 μm or less (hereinafter, these fibers are also simply referred to as "thin fibers") It is also preferred that the layer is disposed adjacent to the second fibrous layer. In either case, these fibers are integrated by at least one of fusion and entanglement to form the fiber aggregate. The central region C of the wiping sheet 1 may be composed only of 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 areas S are folded back when attached to the cleaning tool 220, for example, the contact area with the surface to be cleaned is smaller than the central area C, or the side areas S and the surface to be cleaned are and do not come into contact with each other. Therefore, the side region S may be composed of a fiber assembly consisting of only a single layer of the first fiber layer, or may be composed of a fiber assembly consisting of the first fiber layer and the second fiber layer. . Instead, it may be configured from a fiber aggregate consisting of a first fiber layer, a second fiber layer, and a third fiber layer so as to have the same configuration as the central region C.

The following description will focus on the configuration of the central area C. FIG. 2 and FIGS. 3(a) and 3(b) show an embodiment of the fiber aggregate included in the wet wiping sheet of the present invention. The fiber assembly 1A shown in the figure includes a first fiber layer L1 containing hydrophilic fibers 11, large diameter fibers 12 on each surface of the fiber layer L1, and adjacent to each surface of the first fiber layer L1. It has a three-layer structure including a second fiber layer L2 arranged in the same direction. These fiber layers L1 and L2 together constitute a fiber assembly 1A. Each of the fiber layers L1 and L2 in this embodiment is arranged over the entire area of the wiping sheet 1 in plan view, and the second fiber layer L2 forms each surface 1F and 1R.

In the wiping sheet 1 shown in FIG. 2 and FIGS. 3A and 3B, no other fiber layer is disposed on each surface 1F and 1R, which are the surfaces on which the second fiber layer L2 is disposed. Therefore, large diameter fibers 12 are mainly present on both the first surface 1F and 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.

Each of the fiber layers L1 and L2 constituting the wiping sheet 1 may exist with a clear boundary surface between the fiber layers, as shown in FIG. 2, and as shown in FIGS. 3(a) and (b). As such, 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 preferable that the fibers constituting one fiber layer cross the boundary surface of the adjacent layer and invade the other fiber layer. By doing so, it is possible to easily supply the supported cleaning liquid to the surface to be cleaned through each fiber layer, thereby improving the sustained release of the liquid. As a specific example of such an embodiment, as shown in FIGS. 3(a) and 3(b), the hydrophilic fibers 11 cross the interface between the first fiber layer L1 and the second fiber layer L2 and connect to the second fibers. Examples include a mode in which the large diameter fibers 12 penetrate into the layer L2 side, and a mode in which the large diameter fibers 12 cross the boundary between the first fiber layer L1 and the second fiber layer L2 and penetrate into the first fiber layer L1 side.

In particular, in the wiping sheet 1 in this embodiment, the hydrophilic fibers 11 cross the boundary between the first fiber layer L1 and the second fiber layer L2 and invade the second fiber layer L2 side, and the hydrophilic fibers 11 and large diameter fibers 12 are preferably present on at least one of the first surface 1F and the second surface 1R. With such a configuration, the sustained release of the liquid to the surface to be cleaned is improved, and wiping over a wide range is possible. In addition, since the highly rigid large-diameter fibers 12 scrape off dirt adhering to the surface to be cleaned and float the dirt, dirt can be efficiently collected.

From the viewpoint of improving the sustained release of the liquid to the surface to be cleaned, the number of hydrophilic fibers 11 present 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 present on the wiping surface of the wiping sheet 1 is determined by dividing the total mass (g/cm ² ) per unit area in the planar area of the wiping sheet 1 into the mass of each hydrophilic fiber 11. (g).

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 improving the dirt scraping property and increasing the dirt collection property, 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, and Preferably it is 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. The material, shape, and fiber diameter D2 of the large diameter fibers 12 present in one second fiber layer L2 and the large diameter fibers 12 present in the other second fiber layer L2 are the same. There may be one or different.

From the viewpoint of improving both liquid retention and dirt collection properties, 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 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 second fiber layer L2, the large-diameter fibers 12 present in each second fiber layer L2 may satisfy the above-mentioned ratio.

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.

Since the wiping sheet 1 having the above configuration has the first fiber layer L1 containing the hydrophilic fibers 11, it can hold a large amount of cleaning liquid, and as a result, the wiping sheet can maintain a wet state when in use. Can be kept for a long time. Further, the large diameter fibers 12 included in the second fiber layer L2 can improve the ability to scrape off dirt attached to the surface to be cleaned, thereby increasing the ability to collect dirt.

In particular, the wiping sheet 1 has excellent sustained release of the cleaning liquid during wiping by providing the second fiber layer L2 on each surface of the first fiber layer L1 in the central region C thereof. In detail, the second fiber layer L2 has large diameter fibers 12 that have a larger fiber diameter than the hydrophilic fibers 11, and thus has a structure in which the distance between the fibers is large and there are many voids. In addition, since the large diameter fibers 12 have high fiber rigidity due to their large fiber diameters, they easily rebound against the pressing force that occurs when the wiping sheet 1 is used, and the central region C is in a pressed state. However, the voids existing in the second fiber layer L2 are maintained.

In general, a wet wiping sheet is used by holding it manually or by attaching it to the cleaning tool 220 described above. or between the cleaning tool and the surface to be cleaned. At this time, due to the pressing force generated by the use of the wiping sheet, the cleaning liquid supported on the wiping sheet is pushed out from the fiber aggregate arranged in the central area and released onto the sheet surface. A sheet with a single layer structure consisting of only the first fiber layer L1, as shown in the prior art, or a sheet with a first fiber layer L1 and a second fiber layer L2 disposed only on one side of the first fiber layer L1. When a two-layer sheet is used for wiping, the cleaning liquid is directly released from the first fiber layer when the wiping sheet is pressed against the surface to be cleaned. The cleaning liquid is likely to be discharged excessively to the side of the hand or cleaning tool that comes into direct contact with the first fiber layer, or to the side of the contact surface between the first fiber layer disposed in the central region and the surface to be cleaned. As a result, a sufficient amount of cleaning liquid is released immediately after wiping starts, but if this sheet is used continuously for wiping, the amount of liquid released may decrease and the dirt collection and removal performance may not be fully realized. .

Regarding this point, 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 carried on the first fiber layer L1 can be applied to both sides. It is supplied to the second fiber layers L2, L2. The cleaning liquid supplied to both the second fiber layers L2, L2 is held in the gaps between the respective fiber layers L2, and the cleaning liquid that is not held is gradually released onto the sheet surface so that it oozes out. As a result, the cleaning liquid is continuously supplied to the surface in contact with the surface to be cleaned in the central region C of the wiping sheet 1, and an appropriate amount for wiping is discharged. Further, the cleaning liquid is not unnecessarily discharged to the side of the wiping sheet 1 that is not in contact with the surface to be cleaned, that is, to the hand or the cleaning tool 220 side. As a result, the wiping sheet of the present invention has excellent sustained release properties of cleaning liquid and excellent dirt collection and removal performance. In addition, since the wiping sheet 1 has a central region C and a side region S, the wiping sheet 1 can be easily attached to the cleaning tool 220 by the side region S while supporting the cleaning liquid in the side region S as well. In addition, the central region C allows wiping to be performed with the advantages described above. In addition, the second fiber layer L2, which includes large-diameter fibers 12 and has many voids, can reduce the contact area between the wiping sheet and the surface to be cleaned, thereby reducing the frictional resistance between the wiping sheet and the surface to be cleaned. This also has the advantage of improving operability during use.

Another embodiment of the wiping sheet 1 is shown in FIGS. 4-7. 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.

The wiping sheet 1 shown in FIG. 4 and FIGS. 5(a) and 5(b) is composed of a fiber assembly 1A including hydrophilic fibers 11, large-diameter fibers 12, and small-diameter fibers 13 at least in the central region C. Specifically, as shown in the figure, the wiping sheet 1 includes a first fiber layer L1 containing hydrophilic fibers 11 and large diameter fibers 12 in its central region C, and each side of the first fiber layer L1 a second fiber layer L2 arranged adjacent to the second fiber layer L2, and a third fiber including the small diameter fibers 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 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. 4 and FIGS. 5(a) and (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, and The second surface 1R is formed by the surface 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 this embodiment, the small diameter fibers 13 mainly exist on the first surface 1F, and the large diameter fibers 12 mainly exist on the second surface 1R. In this embodiment, the first surface 1F on which the third fiber layer L3 is arranged is preferably used as the wiping surface.

Each of the fiber layers L1, L2, and L3 constituting the wiping sheet 1 may exist with a clear boundary surface between each fiber layer, similarly to the above-described embodiment, and the boundary surface between each fiber layer may be It may exist in an unclear manner. 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.

Furthermore, as in the above-described embodiment, if the boundary surface between each fiber layer is unclear, the fibers constituting one fiber layer may cross the boundary surface of the adjacent layer and invade the other fiber layer. It is also preferable to be there. As a specific example of this, as shown in FIG. 6, the hydrophilic fibers 11 cross the boundary between the first fiber layer L1 and the second fiber layer L2 and invade the second fiber layer L2 side. , and a mode in which the large diameter fibers 12 cross the interface between the first fiber layer L1 and the second fiber layer L2 and invade the first fiber layer L1 side, or as shown in FIG. 7(a), Examples include an embodiment in which 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 a combination 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. 7(a) and 7(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. It is preferable that at least the tips of the small diameter fibers 13 and the large diameter fibers 12 exist on the first surface 1F, which is the surface of the third fiber layer L3. 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 low porosity structure allows dirt to be efficiently collected and retained, resulting in further improved dirt collection performance.

From the viewpoint of exhibiting sufficient scraping properties for dirt present on the surface to be cleaned, the number of large diameter fibers 12 present 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 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).

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.

In addition, from the viewpoint of easily drawing the cleaning liquid present in the first fiber layer L1 into the third fiber layer L3 side by capillary force and increasing the usage efficiency of the supported cleaning liquid, the diameter of the hydrophilic fiber 11 is smaller than the fiber diameter D1. The ratio of fiber diameters D3 (D3/D1) of the fibers 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 further includes the third fiber layer L3 including the small diameter fibers 13, since the capillary force in the third fiber layer L3 is higher than that in other fiber layers, the first fiber layer L1 and the third fiber layer L3 are It becomes easier to draw the cleaning liquid held in the second fiber layer L2 to the third fiber layer L3 side. 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. Collecting performance 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 and present on the first surface 1F. When wiped while in contact with the surface to be cleaned, the large diameter fibers 12 with high rigidity scrape off dirt existing on the surface to be cleaned, and the third fiber layer L3 can collect and retain the dirt that has been scraped off. Therefore, the ability to collect dirt, especially the ability to collect particulate dirt such as dust and grit, is further improved. Additionally, compared to the case where only the small-diameter fibers come into contact with the surface to be cleaned, the frictional resistance between the wiping sheet and the surface to be cleaned can be further reduced, making it possible to further improve operability during use. There is also an advantage.

Still another embodiment of the wiping sheet 1 is shown in FIGS. 8 and 9(a) and (b). 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 (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 R2) is formed at least in the central region C. 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. 8, the first fibrous layer L1, the second fibrous layer L2 located on the second surface 1R side, and the third fibrous layer L3 are each arranged over the entire area in the sheet surface direction in the central region C.

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. 8 and 9(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 such a configuration, it is possible to further improve dirt collection performance in the presence region R1. 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.

In each of the above-described embodiments, from the viewpoint of improving dirt scraping properties and entanglement properties to further enhance dirt collection properties, Figs. 5(b), 7(a) and (b), and Fig. 9 As shown in (b), the large diameter fibers 12 contained in at least one of both second fiber layers L2 are preferably crimped fibers, and the large diameter fibers 12 contained in both second fiber layers L2 are preferably crimped fibers. More preferably, the fibers are crimped fibers. Moreover, it is preferable that the crimped fibers exist at least on the wiping surface side, and it is also preferable that the crimped fibers are exposed on the sheet surface. 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. When crimped fibers are present in each second fiber layer L2, the number of crimp described above may be satisfied independently in each second fiber layer L2.

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.

The basis weight of the fiber aggregate 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, and , preferably 420 g/m ² or less, more preferably 410 g/m ² or less, even more preferably 400 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 20 g/m ² or more, more preferably 25 g/m ² or more, and still more preferably 30 g/m ² or more in the dry state of the fiber aggregate. Moreover, it is preferably 220 g/m ² or less, more preferably 210 g/m ² or less, even more 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 of each other in the dry state of the fiber aggregate. m ² or more, and 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.

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, more 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.

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, when the third fiber layer L3 is further provided, the third fiber layer L3 may be composed only of the small diameter fibers 13, and in addition to this, other fibers such as the above-mentioned cellulose fibers and synthetic fibers may be used. It may further contain fibers. 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 the wiping sheet of the present invention. Below, a preferred method for manufacturing the wiping sheet with a four-layer structure shown in FIG. 4 will be explained with reference to FIGS. 10 and 11. do. 10 and 11 show a manufacturing apparatus 100 suitably used for manufacturing the four-layered wiping sheet 1 shown in FIG. 4. This manufacturing method includes a step of laminating a fiber layer containing hydrophilic fibers 11 on the upper surface of a fiber layer containing large-diameter fibers 12 to form a first laminate S1 (first lamination step); A step of further laminating a fiber layer containing large diameter fibers 12 on the upper surface of the containing fiber layer to form a second laminate S2 (second lamination step); The process is roughly divided into a process of laminating the fiber layers to form the third laminate S3 (third lamination process) and a process of integrating the laminate (integration process).

The manufacturing apparatus 100 shown in FIGS. 10 and 11 is equipped with a breathable conveyor belt 110 made of 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 forming section 120 for forming a second fiber layer L2 containing large-diameter fibers 12 in a laminated manner, and a first fiber layer L1 containing hydrophilic fibers 11 is formed on the upper surface of the second fiber layer L2. A second forming section 130 that forms a laminate, a third forming section 140 that forms a second fibrous layer L2 containing large diameter fibers 12 on top of the first fibrous layer L1, and a third fibrous layer containing small diameter fibers 13. A fourth forming portion 145 is provided to form the layer L3 in a laminated manner on the upper surface of the second fiber layer L2. By passing through the forming portions 120, 130, 140, and 145 in this order, it is possible to form the first stacked body S1, the second stacked body S2, and then form the third stacked body S3.

Further, at positions facing each of the forming portions 120, 130, and 140, and on the lower surface side of the first laminate S1 and the second laminate S2, the above-mentioned fiber layer is sucked toward the conveyor belt to form a first laminate. A suction box 150 is provided for forming the body S1 and the second laminate S2. In this way, the present manufacturing apparatus has a similar configuration to a manufacturing apparatus used in a general air-laid method.

The fourth forming section 145 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 layer in the second laminate S2. It can be laminated on the upper surface of the fiber layer L2.

An integration processing device 160 for integrating each fiber layer in the third laminate S3 is provided downstream of each forming section 120, 130, 140, 145 in the transport direction MD. The integration processing device 160 shown in FIG. 10 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. A high-pressure water jet is sprayed onto the third fiber layer L3 located on the upper surface side of the third laminate S3 introduced between the support belt 161 and the support belt 161, so that the constituent fibers can be intertwined and integrated.

The integration processing device 160 shown in FIG. 11 is a heating device that heats and integrates the third laminate S3. The integrated processing device 160 is capable of transporting the third stacked body S3 into its interior and heating the third stacked body S3. The manner of heating the third laminate S3 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. 10 and 11 is as follows. First, a fiber layer containing hydrophilic fibers 11 is laminated on the upper surface of a fiber layer containing large-diameter fibers 12 to form a first laminate S1 (first lamination step). Specifically, the large diameter fibers 12 and, if necessary, other fibers are supplied from the first forming section 120, preferably uniformly in the belt surface direction, to form the first fiber layer L1 onto the conveyor belt 110. Let it form on top. Thereafter, the hydrophilic fibers 11 and other fibers such as synthetic fibers are supplied from the second forming section 130, and the first fiber layer L1 is laminated on the second fiber layer L2. 1 laminate S1 is formed.

Next, the large-diameter fibers 12 and other fibers are supplied as needed from the third forming section 140, and the second fiber layer L2 is laminated on the first fiber layer L1 to form a three-layer structure. A two-layered body S2 is formed (second lamination step). When forming the second laminate S2 by the third forming section 140, when forming the second fiber layer L2 over the entire surface direction of the target wiping sheet 1, large diameter fibers are formed over the entire surface direction of the first fiber layer L1. The constituent fibers such as No. 12 may be supplied and used for the next step. 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, a third fiber layer L3 made of a fiber sheet containing small diameter fibers 13 is supplied from the fourth forming section 145, and the third fiber layer L3 is laminated on the second fiber layer L2 to form a four-layer structure. A third stacked body S3 is formed (third stacking step).

Subsequently, each fiber layer in the third laminate S3 is integrated by hydroentangling or heating (integration step). As shown in FIG. 10, when the integrated processing device 160 is in the form of a hydroentangling device, the third laminate S3 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 By going through this process, the fibers of the third laminate S3 are intertwined with each other to form a fiber aggregate 1A.

When the integrated processing device 160 is in the form of a hydroentangling device, the water pressure sprayed onto the third laminate S3 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 third laminate S3 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. 11, 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 third laminate S3. A part of the constituent fibers is melted, and the fibers making up the third laminate S3 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. Heating gas is applied to the third laminate S3 in which two second fiber layers L2 containing latent crimped fibers, which are core-sheath composite fibers, and a third fiber layer L3 containing polypropylene fibers as the small diameter fibers 13 are formed. In the case of spraying, heated gas of 150° C. or more and 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 for a heat treatment time of 20 seconds or more and 80 seconds or less.

Through the above steps, a fiber assembly 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 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.

As shown in FIG. 2, when forming a three-layer fiber assembly 1A having a first fiber layer L1 and two second fiber layers L2, a first lamination step and a second lamination step are performed. After forming the second stacked body S2, the second stacked body S2 may be directly subjected to the integration process without performing the third stacking process by the fourth forming section 145. That is, the first lamination step, the second lamination step, and the integration 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 by heat treatment, and the first fiber layer L1 is made of hydrophilic fibers 11 and other fibers containing heat-fusible resin. It is preferable that the configuration includes the following.

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. In addition, the large diameter fibers 12 included in one second fiber layer L2 are fibers that have not developed crimp, and the large diameter fibers 12 included in the other second fiber layer L2 are fibers that have developed crimp. When manufacturing a wiping sheet, different fibers may be laminated in the first forming section 120 and the third forming section 140.

In order to make the configuration of the fiber layer in the central region C and the configuration of the fiber layer in the side regions S different, for example, the supply width of the fibers supplied from the first forming section 120 and the third forming section 140 must be changed. Alternatively, the width of the fiber sheet supplied from the fourth forming section 145 may be adjusted by increasing or decreasing as appropriate. In particular, such a manufacturing method has the advantage that manufacturing costs can be reduced because there is no need to supply constituent raw materials for each fiber layer to the side regions S, which are less likely to contribute to wiping than the central region C.

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 support the cleaning liquid, for example, the fiber aggregate 1A may be immersed in the cleaning liquid.

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.

Furthermore, the fiber assembly 1A can be folded back at a predetermined position to form a fold line FL before or after the fiber assembly 1A carries the cleaning liquid, or at the same time as carrying the cleaning liquid (the folding step is not shown). ). The fiber aggregate 1A folded back at a predetermined position can be made into a wet wiping sheet and then distributed on the market as a packaged product in which a plurality of sheets are laminated and housed in a packaging bag. The bending lines FL can be formed, for example, at the boundaries between the central region C and the side regions S, respectively.

The wet wiping sheet produced in this manner can be used alone or preferably attached to a cleaning tool having the structure shown in Fig. 1 to clean floors, walls, etc., both outdoors and indoors. For cleaning and wiping objects to be cleaned such as buildings, cabinets, window glass, mirrors, doors, doorknobs and other fittings, rugs, carpets, furniture such as desks and dining tables, kitchens, toilets, bodies, etc., sanitary products, packaging, etc. Can be used.

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 at the planned formation position of the central region C on the second laminate S2 by melt-blowing, electrospinning, or the like. Thereafter, a wet wiping sheet can be manufactured by performing an integration step and a supporting step.

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. Hydrophilic fiber 11 (pulp) A first fiber layer L1 made of a mixed cotton material containing PET fibers in a mass ratio of 4.0:6.0 and having an average fiber diameter of 11.4 μm; Two second fiber layers L2 made of large diameter fibers 12 were formed on each side of the fibers. 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 in both cases. These fiber layers were integrated by an air-laid method to obtain a three-layer fiber assembly 1A having a basis weight of 260 g/m ² .

In this example, each of the fiber layers L1 and L2 was formed over the entire central region C in the sheet surface direction. In addition, the large diameter fibers 12 present in both second fiber layers L2 are all crimped fibers, and the hydrophilic fibers 11 cross the interface between the first fiber layer L1 and the second fiber layer L2 to form the second fibers. Both the hydrophilic fibers 11 and the large diameter fibers 12 penetrated into the layer L2 side and were present on each surface of the second fiber layer L2.

Next, the above-described fiber aggregate 1A was impregnated with a cleaning liquid to produce a wet wiping sheet consisting of a three-layered fiber structure shown in FIG. 2. 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.

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

[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 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.

[Evaluation 1: Evaluation of sustained release properties of cleaning solution]
A load of 0.16 kN/m ² was applied to the wet wiping sheets of Examples and Comparative Examples, and a rectangular tile floor (manufactured by Lixil, Charlotte II) having dimensions of 0.6 m x 0.6 m per sheet was prepared. 36 sheets (equivalent to 12.96 ^m2 ) were wiped as the cleaning target surface. 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 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 sheets of Examples have a higher amount of cleaning liquid supported than the wet wiping sheets of Comparative Examples, and the wet state of the wiping sheets is maintained for a long time, and the cleaning liquid slows down. It can be seen that the release properties are good. In particular, in Example 2 in which the third fiber layer L3 is further provided, the amount of cleaning liquid supported is further increased, and a large amount of cleaning liquid is continuously released from the start to the end of wiping, so that It also shows that it has particularly excellent sustained release properties of the cleaning liquid and can wipe a wide area with a single wiping sheet.

[Evaluation 2: Evaluation of dirt collection ability]
Using the wiping sheets of Example 1 and Comparative Example 1, 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.

As shown in FIG. 13, compared to the wiping sheet of the comparative example, the wiping sheet of the example can wipe without peeling or breaking the fibers after wiping, and removes dirt attached to the surface to be cleaned. It can be seen that the dirt can be collected and retained on the sheet by scraping.

1 Wet wiping sheet 1A Fiber aggregate 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 region S Side region Z Thickness direction 100 Manufacturing equipment 200 Cleaning tool

Claims (6)

A wet wiping sheet having, in plan view, a central region extending in one direction and a pair of side regions adjacent to the central region and extending in the one direction,
The wet wiping sheet is a cleaning tool including a head portion having a fixing portion of the wet wiping sheet on the upper surface, and the central region is located on the lower surface of the head portion, and the side regions are located on the lower surface of the head portion, and the side regions are arranged by the fixing portion on the upper surface. It is used by being attached to the head part so as to be fixed,
The central region has a first fiber layer containing hydrophilic fibers, and a second fiber layer adjacent to each surface of the first fiber layer and containing large diameter fibers having a fiber diameter of 30 μm or more,
further comprising a third fiber layer adjacent to the side on which the first fiber layer is not disposed in one of the second fiber layers and containing small-diameter fibers having 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 that carries cleaning liquid. A wet wiping sheet having, in plan view, a central region extending in one direction and a pair of side regions adjacent to the central region and extending in the one direction,
The wet wiping sheet is a cleaning tool including a head portion having a fixing portion of the wet wiping sheet on the upper surface, and the central region is located on the lower surface of the head portion, and the side regions are located on the lower surface of the head portion, and the side regions are arranged by the fixing portion on the upper surface. It is used by being attached to the head part so as to be fixed,
The central region has a first fiber layer containing hydrophilic fibers, and a second fiber layer adjacent to each surface of the first fiber layer and containing large diameter fibers having a fiber diameter of 30 μm or more,
further comprising a third fiber layer adjacent to the side on which the first fiber layer is not disposed in one of the second fiber layers and containing small-diameter fibers having 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 that carries cleaning liquid. The large diameter fibers cross the boundary between the second fiber layer and the third fiber layer and invade the third fiber layer,
The wet wiping sheet 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. The wet wiping sheet according to any one of claims 1 to 3, wherein the third fiber layer has a basis weight of 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 4 , wherein the large diameter fibers are crimped fibers. The wet wiping sheet according to any one of claims 1 to 5 , wherein the large diameter fiber is a composite fiber of polyethylene terephthalate and polyethylene.

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