JPWO2020071250A1 - Wiping sheet - Google Patents

Abstract

The wiping sheet (1) of the present invention contains at least a first fiber (11) and a second fiber (12) having a diameter smaller than that of the fiber, and the fiber aggregate (1A) formed by entwining these fibers. ), And has a first surface (1F) and a second surface (1R) located on the opposite side of the first surface (1F). The abundance ratio of the second fiber (12) is higher on the first surface (1F) than on the second surface (1R). At least the first fiber (11) is a deformed fiber having a non-circular cross section. It is also preferable that the cleaning liquid is supported on the fiber assembly (1A). It is also preferable that the first fiber (11) is a fiber made of a thermoplastic resin. It is also preferable that the tensile elastic modulus is 1.3 × 10-3 N / mm2 or more.

Description

The present invention relates to a wiping sheet.

Fibers made from thermoplastic resins are used for various purposes in the form of non-woven fabrics in which the fibers are entangled. For example, Patent Document 1 describes a washed cloth having a fiber entanglement mainly composed of ultrafine fibers having an average fiber diameter of 0.3 to 3.0 μm and an irregular cross section. It is described in the same document that this washed cloth is used for cleaning the surface of a substrate for a magnetic recording medium.

Further, Patent Document 2 discloses a non-woven fabric composed of 20 to 80% by mass of a polyester fiber having a flat cross section and 20 to 80% by mass of a cellulosic fiber. This non-woven fabric has high liquid absorption and retention power and release property of liquids such as water and chemicals, and has moderate bulkiness and flexibility, so that it can be used for interpersonal cleaning and beauty. It is described in.

Japanese Unexamined Patent Publication No. 2013-124422 US 2015/359400 A1

The present invention relates to a wiping sheet including at least a first fiber and a second fiber having a diameter smaller than that of the fiber, and comprising a fiber aggregate formed by entwining these fibers. The wiping sheet has a first surface and a second surface located on the opposite side of the first surface. In the wiping sheet, the abundance ratio of the second fiber is higher on the first surface than on the second surface. The wiping sheet is a deformed fiber in which at least the first fiber has a non-circular cross section.

FIG. 1 is a schematic cross-sectional view showing an embodiment of the wiping sheet of the present invention. 2 (a) and 2 (e) are schematic perspective views of the cross-sectional shape of the deformed fiber used in the wiping sheet of the present invention. 3 (a) to 3 (c) are plan-enlarged views of the cross-sectional shapes of the deformed fibers in FIGS. 1 (b), (d) and (e). FIG. 4 is a schematic view showing an embodiment of an uneven portion of a macroscopic pattern on the first surface of the wiping sheet of the present invention. FIG. 5 is a schematic view of a manufacturing apparatus preferably used for manufacturing the wiping sheet of the present invention. FIG. 6 is a schematic view of a concavo-convex portion forming member for forming a concavo-convex portion of a macroscopic pattern.

Detailed description of the invention

The cleaning processed cloths and non-woven fabrics described in Patent Documents 1 and 2 are intended for cleaning the surface of a substrate, for cleaning for people, or for beauty purposes, and collect dirt when cleaning the floor surface or the like. Is not disclosed at all. In addition, the strength of the non-woven fabric or the like containing ultrafine fibers is insufficient, and as a result, the sheet is liable to break during use.

Therefore, the present invention relates to a wiping sheet that solves the drawbacks of the prior art.

Hereinafter, the wiping sheet of the present invention will be described based on its preferred embodiment. In the present invention, "wiping" includes both cleaning and cleaning, for example, cleaning of buildings such as floors, walls, ceilings and pillars, cleaning of fittings and fixtures, wiping of articles, etc. Includes cleaning of the body and equipment related to the body. In addition, in this specification, the term "wiping sheet" simply refers to one in which a cleaning liquid is supported and one in which a cleaning liquid is not supported, depending on the context.

The wiping sheet comprises a fiber assembly containing at least a first fiber and a second fiber having a diameter smaller than that of the first fiber. The first fiber and the second fiber are entangled with each other by the first fiber, the second fiber, and the first fiber and the second fiber to form the above-mentioned fiber aggregate. That is, the fiber aggregate used for the wiping sheet is a composite fiber aggregate mainly composed of the entanglement of the first and second fibers. The wiping sheet may be composed of only the fiber aggregates, or may include other sheet materials, other members, or both in addition to the fiber aggregates. The wiping sheet of the present invention may be a fiber aggregate in which a cleaning liquid is not supported (hereinafter, this embodiment is also referred to as "dry type"), or may be a fiber aggregate in which a cleaning liquid is supported (hereinafter, this mode is also referred to as "dry type"). , This aspect is also referred to as "wet").

FIG. 1 shows a cross-sectional view of a fiber assembly provided in the wiping sheet of the present invention. As shown in the figure, the fiber assembly 1A in the wiping sheet 1 includes a first fiber 11 and a second fiber 12 having a diameter smaller than that of the first fiber. 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. As shown in FIG. 1, in the wiping sheet 1, the second fiber 12, which is a fiber having a small fiber diameter, is mainly present on the first surface 1F of the figure, and the first fiber 11 is present on the second surface 1R. Is mainly present. The first surface 1F is provided as a wiping surface when the wiping sheet is used. In addition, "mainly present" means that the abundance ratio of any of the 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.

The abundance ratio of the second fiber 12 on the first surface 1F is preferably 40% or more, more preferably 50% or more, still more preferably 60% or more in terms of area ratio. Further, it is preferably 100% or less, more preferably 90% or less, and further preferably 85% or less. The abundance ratio of the second fiber 12 on the first surface 1F is preferably 40% or more and 100% or less, more preferably 50% or more and 90% or less, and 60% or more in terms of area ratio. It is more preferably 85% or less. With such an abundance ratio, the dense and low porosity structure formed by the small-diameter fibers can enhance the collection performance of fine particle stains and enhance the sheet strength at the time of use. Further, the sustained release property of the cleaning liquid in the wet mode can be enhanced.

The abundance ratio of the first fiber 11 on the first surface 1F is preferably 0% or more, more preferably 1% or more, and further preferably 5% or more in terms of area ratio. Further, it is preferably 60% or less, more preferably 40% or less, and further preferably 35% or less. The abundance ratio of the first fiber 11 on the first surface 1F is preferably 0% or more and 60% or less, more preferably 1% or more and 40% or less, and 5% or more in terms of area ratio. It is more preferably 35% or less. With such an abundance ratio, the structure having a high porosity formed by the large-diameter fibers can enhance the collection performance of fiber stains such as hair, and can enhance the sheet strength at the time of use. Further, the sustained release property of the cleaning liquid in the wet mode can be enhanced.

Similarly, the abundance ratio of the second fiber 12 on the second surface 1R is preferably 1% or more, more preferably 3% or more, and 5% or more in terms of area ratio. Is more preferable, 60% or less is preferable, 40% or less is more preferable, and 35% or less is further preferable. The abundance ratio of the second fiber 12 on the second surface 1R is preferably 1% or more and 60% or less, more preferably 3% or more and 40% or less, and 5% or more in terms of area ratio. It is more preferably 35% or less.

Similarly, the abundance ratio of the first fiber 11 on the second surface 1R is preferably 50% or more, more preferably 65% or more, and more preferably 70% or more in terms of area ratio. It is more preferably 100% or less, more preferably 90% or less, and further preferably 87% or less. The abundance ratio of the first fiber 11 on the second surface 1R is preferably 50% or more and 100% or less, more preferably 65% or more and 90% or less, and 70% or more in terms of area ratio. It is more preferably 87% or less.

The abundance ratio of the first fiber 11 and the second fiber 12 on each surface can be measured as an area ratio using, for example, a confocal laser scanning microscope. Specifically, image data is acquired with the first surface 1F or the second surface 1R as observation targets. Each of the obtained images is binarized by setting a threshold value at the brightness boundary between the first fiber and the second fiber using image processing software such as ImageJ. Then, the area having each color is calculated, and the area ratio of each fiber is calculated.

When considering a virtual surface parallel to the first surface 1F of the wiping sheet, the abundance ratio of the second fiber 12 in the virtual surface is expressed as an area ratio, and the thickness on the opposite side of the first surface 1F. It is preferable that the number decreases stepwise, continuously, or in combination thereof in the longitudinal direction Z. In particular, a virtual surface parallel to the first surface 1F is provided for a portion extending from 50% to 100% of the thickness of the wiping sheet along the thickness direction Z of the wiping sheet with the second surface 1R as a reference (zero surface). By setting the abundance ratio of the second fiber 12 in the above in the range of 50% or more and 100% or less in terms of area ratio, the sheet strength and the dirt collecting property can be made high. In addition, the sustained release property of the cleaning liquid in the wet mode can be enhanced.

The ratio of the sheet thickness in which the abundance ratio of the second fiber is in the range of 50% or more and 100% or less is preferably 1% or more and 90% or less, more preferably 5% or more and 70% or less, and 7% or more. 50% or less is more preferable. This abundance ratio can be calculated as the above-mentioned area ratio by performing Raman imaging in the sheet thickness direction using, for example, a confocal laser scanning microscope.

In the wiping sheet of the present invention, at least the first fiber 11 having a large diameter is a deformed fiber. The deformed fiber has a non-circular cross section. The non-circular cross section of the fiber means that the cross section of the fiber has a shape other than a perfect circle. From the viewpoint of effectively exhibiting the sheet strength and the dirt collecting performance, it is preferable that at least the first fiber 11 having a large diameter is a deformed fiber, and both the first fiber and the second fiber are a deformed fiber. It is more preferable that it is.

Examples of the deformed fiber having the shape of the cross section of the fiber include a triangle shown in FIG. 2 (a), a convex polygon such as a quadrangle, a pentagon and a hexagon, or a regular polygon, and is shown in FIG. 2 (b). Examples include those having a cross-sectional shape such as a star-shaped polygon, an elliptical shape shown in FIG. 2 (c), a W-shape shown in FIG. 2 (d), and a multi-leaf shape shown in FIG. 2 (e). As long as the effect of the invention is exhibited, there is no particular limitation.

The first fiber 11 is a deformed fiber having at least one convex portion having a sharp top, more preferably two or more, and even more preferably three or more convex portions in its cross-sectional shape. A sharp apex is defined as (b) one straight line and one when the contour of the convex portion in the cross-sectional shape of the deformed fiber is defined by (a) two non-parallel straight lines intersecting. There are cases where it is defined by intersecting the curves of (c) and cases where it is defined by intersecting two curves. For example, the deformed fiber shown in FIG. 2 (a) has three sharp tops, the deformed fiber shown in FIG. 2 (b) has six sharp tops, and the deformed fiber shown in FIG. 2 (e) is sharp. It has eight tops. In the present invention, one kind of deformed fiber may be used alone, or two or more kinds of deformed fibers having different cross-sectional shapes may be used in combination.

The wiping sheet of the present invention has a high tensile elastic modulus because its constituent fibers contain deformed fibers. From the viewpoint of increasing the strength of the wiping sheet, the tensile elastic modulus of the wiping sheet ^{is preferably 1.3 × 10 -3} N / mm ² or more, and 1.4 × 10 ^-3 N / mm ² or more. Is more preferable, and 1.5 × 10 ^-3 N / mm ² or more is further preferable. The upper limit of the tensile elastic modulus is not particularly limited, but 5.0 × 10 ^-3 N / mm ² or less is realistic. The tensile elastic modulus can be obtained from, for example, the difference in tensile strength (N / mm) at two points and the difference in displacement (mm) in these tensile strengths. The measuring method will be described in detail in Examples described later.

From the viewpoint of achieving both sheet strength and dirt collection efficiency at a high level, it is preferable that the fineness (dtex) of the first fiber is higher than the fineness (dtex) of the second fiber. Specifically, the ratio of the fineness (dtex) of the first fiber to the fineness (dtex) of the second fiber is preferably 10 or more, more preferably 15 or more, and more preferably 25 or more. It is more preferably 2000 or less, more preferably 1500 or less, and even more preferably 1000 or less.

From the same viewpoint, the fineness of the first fiber contained in the wiping sheet is preferably 0.5 dtex or more, more preferably 1 dtex or more, further preferably 1.2 dtex or more, and the fineness thereof. The upper limit is preferably 3 dtex or less, more preferably 2.5 dtex or less, and further preferably 2 dtex or less.

From the same viewpoint, the fineness of the second fiber contained in the wiping sheet ^{is preferably 1.5 × 10 -3} dtex or more, more preferably 2.5 × 10 ^-3 dtex or more, 4 It is more preferably .5 × 10 ^{-3 dtex or more.} The fineness of the second fiber ^{is preferably 3.0 × 10 -1} dtex or less, more preferably 1.0 × 10 ^-1 dtex or less, and 5.0 × 10 ^-1 dtex or less. Is more preferable.

The first fibers 11 and the second fibers 12 constituting the wiping sheet 1 may be either synthetic fibers or natural fibers, but at least the first fibers are considered from the viewpoint of fiber molding ease and production efficiency. Is preferably a synthetic fiber made of a thermoplastic resin, and more preferably both fibers 11 and 12 are synthetic fibers made of a thermoplastic resin.

Examples of the thermoplastic resin include polyolefin resins such as polyethylene (PE) and polypropylene (PP), polyester resins such as polyethylene terephthalate (PET), polyamide resins, vinyl resins such as polyvinyl chloride and polystyrene, and polyacrylic acids. Examples thereof include acrylic resins such as polymethyl methacrylate and fluororesins such as polyperfluoroethylene. Examples of natural fibers include various cellulose fibers, for example, hydrophilic fibers such as pulp, cotton, rayon, lyocell and tencel. These fibers may be used alone or in combination of two or more.

From the viewpoint of increasing the degree of freedom of the constituent fibers and enhancing the dirt collecting performance, it is preferable that the fibers constituting the wiping sheet are entangled without being fused to each other. By having such a configuration, it is possible to improve the dirt collecting performance while maintaining the strength of the sheet, and when the wiping sheet is used as a wet mode, the cleaning liquid is supported per unit area. It also has the advantage of increasing the amount.

The fiber length of the first fiber depends on the method for producing the fiber, but is preferably 1 mm or more and 100 mm or less, more preferably 10 mm or more and 90 mm or less, and further preferably 20 mm or more and 60 mm or less. The fiber length of the second fiber depends on the method for producing the fiber, but is preferably 1 mm or more. Examples of the method for producing the first fiber 11 and the second fiber 12 include a spunbond method, a melt blown method, and an electrospinning method (electrospinning method). From the viewpoint of further increasing the production efficiency of the small-diameter fibers, it is preferable that at least the second fiber is a synthetic fiber made of a thermoplastic resin and is produced by an electric field spinning method.

The length of the longest line segment that crosses the cross section of the deformed fiber is defined as A, and the length of the longest line segment that is orthogonal to the line segment and crosses the cross section is defined as B. Occasionally (see FIGS. 3A to 3C), the ratio of length A to length B (A / B) is preferably 1.2 or more, more preferably 1.5 or more. Preferably, it is more preferably 2 or more, and the upper limit thereof is preferably 5 or less, more preferably 4 or less, and further preferably 3 or less. Specifically, the A / B value is preferably 1.2 or more and 5 or less, more preferably 1.5 or more and 4 or less, and further preferably 2 or more and 3 or less. With such a configuration, the fibers constituting the wiping sheet are easily entangled with fiber stains such as hair, and these stains can be caught on the fibers and removed from the surface to be wiped.

Regarding the above-mentioned lengths A and B, to give an example of a cross-sectional shape other than the shapes shown in FIGS. In a)), the length A is the length of one side of an equilateral triangle, and the length B is the length of a perpendicular line drawn from a certain apex to one side. Further, in a deformed fiber having an elliptical cross-sectional shape (see FIG. 2C), the length A is the major axis of the ellipse and the length B is the minor axis of the ellipse.

When the wiping sheet contains two or more types of deformed fibers having different cross-sectional shapes, the lengths A and B are the average value of A and the average value of B measured for all types of deformed fibers. That is.

From the viewpoint of having both operability at the time of wiping and dirt collecting property, the length A is preferably 1 μm or more, preferably 5 μm or more, provided that the above-mentioned range of A / B is satisfied. It is more preferably 10 μm or more, and the upper limit thereof is preferably 80 μm or less, preferably 50 μm or less, and preferably 25 μm or less. From the same viewpoint, the length B is preferably 0.2 μm or more, more preferably 1 μm or more, and further preferably 2 μm or more, provided that the above-mentioned range of A / B is satisfied. It is preferable, and the upper limit thereof is preferably 40 μm or less, preferably 20 μm or less, and preferably 15 μm or less.

As shown in FIGS. 3A to 3C, when the contour line in the cross section of the deformed fiber is viewed along the circumferential direction, the concave portions located between the plurality of convex portions P and the adjacent convex portions P. In the case of a shape having R, when the length of the line segment connecting the vertices of the adjacent convex portions P is C, and the length of the perpendicular line drawn from the line segment to the bottom position of the concave portion R is D. (See FIGS. 3A to 3C), the C / D value is preferably 0.1 or more, more preferably 1 or more, further preferably 2 or more, and its upper limit. Is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less. By having such a configuration, the surface area of the fiber alone is increased and the contact area with dirt is increased, so that the dirt collection property can be further improved.

When observing the cross section of the deformed fiber, if the length C of the line segment connecting the vertices of the adjacent convex portions P selected arbitrarily is different, the value of C for calculating the value of C / D is all. Let it be the average value of C values. Similarly, when D is different in the length of the perpendicular line in the recess R arbitrarily selected, the value of D for calculating the value of C / D is the average value of all the values of D. When referring to the values of C and D in the following description, the values are the average values of C and D.

From the viewpoint of improving the operability at the time of wiping and the efficiency of collecting dirt, the length C is preferably 0.1 μm or more, preferably 0.5 μm or more, provided that the above-mentioned C / D range is satisfied. It is more preferably 1 μm or more, and the upper limit thereof is preferably 20 μm or less, preferably 10 μm or less, and preferably 5 μm or less. From the same viewpoint, the length D is preferably 0.1 μm or more, more preferably 0.5 μm or more, and more preferably 1 μm or more, provided that the above-mentioned C / D range is satisfied. Is more preferable, and the upper limit thereof is preferably 20 μm or less, preferably 10 μm or less, and preferably 5 μm or less.

The above-mentioned lengths A to D can be measured by the following measuring methods. That is, the prepared fiber aggregate was cut using a razor or the like while maintaining the cross-sectional shape of the fiber, and then the cross section was vacuum-deposited with Pt. Using a scanning electron microscope (JSM-IT100, manufactured by JEOL Ltd.), observe the cross section of the Pt-deposited fiber aggregate at a magnification of 500 to 1000 times, and use the attached software length measurement tool to observe the above in the fiber cross section. Lengths A to D were measured respectively.

The wiping sheet of the present invention may be composed of only the first fiber 11 and the second fiber 12, and may further contain other fibers in addition to these fibers. As the other fibers, the synthetic fibers and natural fibers described above can be used. These can be used alone or in combination of two or more. The cross section of the other fiber may be circular (non-deformed) or non-circular (deformed). The other fibers are preferably contained in the fiber aggregate in a proportion of 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less.

When the wiping sheet of the present invention contains other fibers, the fineness of the fibers is preferably 0.6 dtex or more, preferably 1.0 dtex or more, from the viewpoint of operability during wiping and dirt collection efficiency. It is more preferable to have 1.2 dtex or more, and it is more preferable to have 1.2 dtex or more. Further, it is preferably 4.0 dtex or less, more preferably 3.5 dtex or less, and further preferably 3.0 dtex or less.

The strength of the wiping sheet in terms of the appropriate basis weight of the fiber aggregate constituting the wiping sheet, 40 g / m ² or more preferably, 45 g / m ² or more preferably, 50 g / m ² or more is more preferably, also the upper limit thereof is preferably 140 g / ^{m 2} or less, more preferably 100 g / ^{m 2} or less, 80 g / ^{m 2} or less is more preferable. Specifically, the basis weight of the fiber aggregate constituting the wiping sheet ^{is preferably 40 g / m 2} or more and 140 g / m ² or less, more preferably 45 g / m ² or more and 100 g / m ² or less, and 50 g / m ² or more. 80 g / m ² or less is more preferable.

From the same viewpoint, the thickness of the wiping sheet is preferably 0.5 mm or more, more preferably 1.0 mm or more under a load of ^{40 N / m 2, and the upper limit thereof is 2 under the same load.} It is preferably 5.5 mm or less, and more preferably 3 mm or less.

The wiping sheet may be used as it is (so-called dry mode) at the time of wiping, or may be used in a mode in which a cleaning liquid is applied, sprayed, supported or impregnated with the fiber aggregate (so-called wet mode). You may. These modes can be selected according to the type of dirt adhering to the surface to be wiped and the physical properties of the object to be wiped. From the viewpoint of improving the cleaning efficiency on the surface to be cleaned, it is preferable that the cleaning liquid is supported on the fiber aggregate constituting the wiping sheet. That is, the wiping sheet of the present invention is preferably in a wet mode. Since the fiber aggregate contains irregular fibers, the gaps between the fibers can be increased, and as a result, the liquid retention property of the cleaning liquid in the wiping sheet is improved while improving the dirt collection property. Benefits are also played.

When the wiping sheet is used in a wet mode at the time of wiping, the cleaning liquid supported on the sheet uses water alone, an aqueous solution containing an additive, or the like having a general composition used for a wet wiping sheet. be able to. The additive used in the cleaning liquid is at least one selected from the group consisting of surfactants, bactericides, fragrances, fragrances, deodorants, pH adjusters, alcohols, abrasive particles, gloss enhancers and thickeners. Can be mentioned.

As shown in FIG. 4, the wiping sheet of the present invention composed of the fiber aggregate containing the above-mentioned deformed fibers is a substantially rectangular sheet having a longitudinal direction X and a width direction Y orthogonal to the longitudinal direction X. From the viewpoint of effectively collecting fine particle stains and fiber stains such as hair, the wiping sheet 1 has a macroscopic pattern uneven portion having a curved portion on at least one surface thereof, as shown in the figure. It is more preferable that the surface used as the wiping surface (first surface 1F in FIG. 1) has a concavo-convex portion of a macroscopic pattern having a curved portion.

As shown in the figure, a pattern concave portion 3 and a pattern convex portion 4 forming a concave-convex portion of a macroscopic pattern are formed on one surface of the wiping sheet 1. The boundary line between the pattern concave portion 3 and the pattern convex portion 4 has a curved portion when viewed macroscopically. When the uneven portion of the macroscopic pattern is formed on one surface, the other surface is flat without forming complementary irregularities derived from the uneven portion of the macroscopic pattern.

The uneven portion of the macroscopic pattern is not limited to the macroscopic pattern shown in the figure, and for example, the macroscopic pattern shown in Japanese Patent Application Laid-Open No. 2017-11382 and figures such as straight lines, curves, circles, and polygons are appropriately combined. It may be a macroscopic pattern. It should be noted that, macroscopically, the curved shape constitutes a pattern uneven portion except for a curve forming a microscale fine hole and a curve forming a drainage hole having a diameter of about 1.5 to 2 mm. This means that it can be visually confirmed that a part of the side of the figure is a curved line, and from such a viewpoint, the area of each pattern convex portion 4 surrounded by the pattern concave portion 3 is 300 mm ² or more. As described above, it is preferable to form the pattern concave portion 3 and the pattern convex portion 4. By having the uneven portion of such a macroscopic pattern, there is also an advantage that the design of the wiping sheet itself is enhanced.

When focusing on one fiber aggregate, the wiping sheet of the present invention may be composed of a fiber aggregate in which the boundary between the existence region of the first fiber and the second fiber in the sheet thickness direction is not clear. Alternatively, it may be composed of a fiber aggregate having a two-layer structure of a layer containing the first fiber and a layer containing the second fiber. Further, the wiping sheet of the present invention is composed of a fiber aggregate having a multi-layer structure of three or more layers including a layer containing a first fiber, a layer containing a second fiber, and a layer containing other fibers. May be good.

The wiping sheet of the present invention may be composed of only one fiber aggregate (whether single layer or multilayer) containing irregularly shaped fibers, or a first fiber aggregate containing first and second fibers. And may have a multi-ply laminated structure in which a second fiber aggregate with or without deformed fibers or a sheet material other than the fiber aggregate is superposed. Examples of the sheet material include non-woven fabric, woven fabric, and paper.

From the viewpoint of further increasing the strength of the wiping sheet, the wiping sheet of the present invention may further include a scrim net for supporting the fiber aggregates constituting the sheet. When the scrim net is provided, the scrim net is preferably arranged in the central region in the thickness direction of the fiber aggregate. The scrim net can be integrally entangled with the deformed fibers constituting the fiber aggregate, and examples thereof include a net-like, a lattice-like, and a strand-like forms.

A resin can be used as a raw material constituting the scrim net. Examples of the resin include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyamide resins such as nylon 6 and nylon 66, acrylonitrile resins such as polyacrylonitrile, vinyl resins such as polyvinyl chloride and polystyrene, and poly. A vinylidene resin such as vinylidene chloride can be used.

From the viewpoint of achieving both the entanglement of the constituent fibers and the scrim net and the strength of the wiping sheet, the wire diameter (diameter in the cross section) of the scrim net can be appropriately adjusted according to the degree of entanglement of the fibers, but is 10 μm or more. It is preferably 500 μm or more, more preferably 2000 μm or less, and further preferably 1000 μm or less. The wire diameter of the scrim net may be partially different or the same, and when the wire diameters are partially different, the wire diameter of the scrim is the average value. The basis weight of the scrim net ^{is preferably 1 g / m 2} or more, more preferably 3 g / m ² or more, more preferably 20 g / m ² or less, still more preferably 10 g / m ² or less.

The above has been described with respect to one embodiment of the wiping sheet of the present invention, and a suitable manufacturing method of the wiping sheet will be described below with reference to FIG. FIG. 5 shows a manufacturing apparatus 10 preferably used for manufacturing a wiping sheet. The manufacturing apparatus 10 includes a web forming portion 20, a first water flow entanglement portion 30, and a second water flow entanglement portion 40 in this order along the transport direction (MD direction). The present manufacturing method includes a step of forming a fiber aggregate containing irregularly shaped fibers by water flow confounding, and optionally includes a step of forming an uneven portion of a macroscopic pattern on one surface of the fiber aggregate. You may. In the following description, the transport direction (MD direction) and the width direction Y of the sheet coincide with each other, and the direction orthogonal to the transport direction and the longitudinal direction X of the sheet coincide with each other.

First, the web of the first fiber 11 is unwound from the card machine 21 in the web forming unit 20 via the guide roll 22. When the wiping sheet is provided with a scrim net, the scrim net 15 is unwound from the scrim roll 25 together with the web of the first fiber 11. By these feedings, the web and scrim net of the first fiber 11 are laminated.

Next, in the first water flow confounding portion 30, the web of the first fiber 11 (or the laminate of the web of the first fiber 11 and the scrim net 15) is moved in the MD direction by the first support belt 32 through which water can permeate. While being conveyed, the water flow is entangled by the high-pressure water flow ejected from the first water flow nozzle 31 (first entanglement step). Through this step, the first fibers 11 are entangled with each other to form an entanglement of the first fibers 11. In the case where the scrim net is provided, the first fibers 11 are entangled with each other by this step, and the first fiber 11 and the scrim net 15 are integrally entangled with each other, and the scrim net is arranged. An entanglement of the first fibers 11 is formed. In this step, the water pressure sprayed from the first water flow nozzle 31 is preferably 30 kg / cm ² or more and 80 kg / cm ² or less, more preferably 40 kg / cm ² or more and 60 kg / cm ² or less, and the web of the first fiber 11. The production can be carried out by preferably setting the transport speed in the MD direction to 2 m / min or more and 10 m / min or less, and more preferably 4 m / min or more and 8 m / min or less.

After the entanglement of the first fibers 11 is formed, the entanglement 12A of the second fibers 12 is laminated on the upper surface thereof, and the fiber assembly 1A is formed by water flow entanglement (second entanglement step). Specifically, the entangled body of the first fiber 11 is conveyed in the MD direction, and the entangled body 12A of the sheet-shaped second fiber 12 unwound from the raw fabric roll 41 is placed on the upper surface of the entangled body. Laminate to form a laminated body 5. By blowing a high-pressure water stream from the second water flow nozzle 43 onto the laminate 5, the constituent fibers of each confounding body are three-dimensionally entangled to form a fiber assembly 1A. The water pressure sprayed from the second water flow nozzle 43 and the transport speed of the laminated body 5 can be in the same range as the above-described first entanglement step. In the fiber aggregate 1A formed in this step, the second fiber 12 is mainly present on the upper surface thereof, and the first fiber 11 (or the entangled combination of the first fiber 11 and the scrim net 15) is present on the lower surface thereof. ) Is mainly present.

After the second water flow entanglement step, the fiber aggregate 1A may be used as it is as the wiping sheet 1 in the dry or wet mode, and if necessary, on one surface of the fiber aggregate 1A as shown in FIG. The uneven portion of the macroscopic pattern may be formed, and this may be used as the wiping sheet 1 in the dry or wet mode.

For example, when the uneven portion of the macroscopic pattern is formed on the surface (first surface 1F in FIG. 1) in which the second fiber 12 is mainly present in the fiber aggregate 1A, the uneven portion shown in FIG. 6 is formed. The forming member 50 is arranged on the surface side of the fiber assembly 1A where the second fiber 12 is mainly present, and a high-pressure water stream is sprayed from the surface opposite to the surface (second surface 1R in FIG. 1). Thereby, the pattern concave portion 3 and the pattern convex portion 4 complementary to the uneven shape of the uneven portion forming member 50 can be formed on the first surface 1F of the fiber assembly 1A. The water pressure sprayed on the fiber aggregate 1A and the transport speed of the fiber aggregate can be in the same range as the above-mentioned entanglement step.

The fiber aggregate 1A produced as described above may be used as it is as a dry wiping sheet after being formed into a rectangular shape as shown in FIG. 4, for example, and the cleaning liquid is supported on the fiber aggregate 1A ( It can also be used as a wet wiping sheet (supporting step). In the step of supporting the cleaning liquid, the amount of the cleaning liquid supported on the fiber assembly 1A is preferably 1 g / sheet or more when the dimensions of the wiping sheet 1 are set to 285 mm × 205 mm, for example, as described in Examples described later. 10 g / sheet or more is further preferable, 40 g / sheet or less is preferable, and 25 g / sheet or less is further preferable. In other words, preferably 17 g / ^{m 2} or more, more preferably 117 g / ^{m 2} or more, preferably 690 g / ^{m 2} or less, more preferably 430 g / ^{m 2} or less.

The wiping sheet manufactured in this way can be attached to a cleaning tool such as a wiper or a building such as a floor or a wall surface, a cabinet, a window glass, a mirror, a door, a door knob, or the like. It can also be used for rugs, carpets, furniture such as desks and dining tables, kitchens, toilets, body cleaning, hygiene products, packaging, etc.

Although the present invention has been described above based on its preferred embodiment, the present invention is not limited to the above embodiment. In order to form a fiber aggregate containing fibers other than the first and second fibers, for example, in the web forming unit 20, a second card machine is arranged, and a web of other fibers is placed from the card machine. May be fed out and laminated. Then, by performing an entanglement step, a fiber aggregate containing other fibers in addition to the first fiber can be formed.

Further, the following wiping sheet is disclosed with respect to the above-described embodiment of the present invention.
<1>
It comprises at least a first fiber and a second fiber having a diameter smaller than that of the fiber, and has a fiber aggregate formed by entwining these fibers, and is located on the first surface and the opposite side of the first surface. A wiping sheet having a second surface and
The abundance ratio of the second fiber is higher on the first surface than on the second surface.
A wiping sheet in which at least the first fiber is a deformed fiber whose cross section is non-circular.

<2>
The wiping sheet according to <1>, wherein both the first fiber and the second fiber are the deformed fibers.
<3>
The wiping sheet according to <1> or <2>, wherein the deformed fiber has a shape of a triangular cross section, a convex polygon such as a quadrangle, a pentagon, and a hexagon, or a regular polygon.
<4>
The wiping sheet according to any one of <1> to <3>, wherein the deformed fiber has a multi-leaf shape in its cross section.
<5>
The wiping sheet according to any one of <1> to <4>, which is composed of only the fiber aggregate.
<6>
The wiping sheet according to any one of <1> to <4>, which comprises another sheet material or other member in addition to the fiber aggregate.

<7>
The abundance ratio of the second fiber on the first surface is preferably 40% or more, more preferably 50% or more, further preferably 60% or more, and further preferably 60% or more, in terms of area ratio. The wiping sheet according to any one of <1> to <6>, wherein it is preferably 100% or less, more preferably 90% or less, and further preferably 85% or less.
<8>
The abundance ratio of the second fiber on the second surface is preferably 1% or more, more preferably 3% or more, further preferably 5% or more, and further preferably 5% or more, in terms of area ratio. , 60% or less, more preferably 40% or less, still more preferably 35% or less, the wiping sheet according to any one of <1> to <7>.
<9>
The abundance ratio of the first fiber on the first surface is preferably 0% or more, more preferably 1% or more, further preferably 5% or more, and further preferably 5% or more, in terms of area ratio. , 60% or less, more preferably 40% or less, still more preferably 35% or less, the wiping sheet according to any one of <1> to <8>.
<10>
The abundance ratio of the first fiber on the second surface is preferably 50% or more, more preferably 65% or more, further preferably 70% or more, and further preferably 70% or more, in terms of area ratio. The wiping sheet according to any one of <1> to <9>, wherein it is preferably 100% or less, more preferably 90% or less, and further preferably 87% or less.

<11>
The wiping sheet according to any one of <1> to <10>, wherein the constituent fibers of the fiber aggregate are not fused to each other.
<12>
The wiping sheet according to any one of <1> to <11>, wherein the cleaning liquid is supported on the fiber assembly.
<13>
The wiping sheet according to <12>, wherein the cleaning liquid is an aqueous solution containing an additive.
<14>
The additive is at least one selected from the group consisting of surfactants, bactericides, fragrances, fragrances, deodorants, pH adjusters, alcohols, abrasive particles, gloss enhancers and thickeners. The wiping sheet according to <13>.
<15>
The wiping sheet according to any one of <1> to <14>, wherein the first fiber is a fiber made of a thermoplastic resin.

<16>
The wiping sheet according to any one of <1> to <15>, wherein the tensile elastic modulus is 1.3 × 10 ^-3 N / mm ^{2 or more.}
<17>
The tensile elastic modulus is ^{preferably 1.3 × 10 -3} N / mm ² or more, more preferably 1.4 × 10 ^-3 N / mm ² or more, and 1.5 × 10 ^-3 N. The wiping sheet according to any one of <1> to <16>, wherein it is more preferably / mm ² or more, and preferably 5.0 × 10 ^-3 N / mm ^{2 or less.}
<18>
The wiping sheet according to any one of <1> to <17>, wherein the ratio of the fineness of the first fiber to the fineness of the second fiber is 10 or more and 2000 or less.
<19>
The ratio of the fineness of the first fiber to the fineness of the second fiber is preferably 10 or more, more preferably 15 or more, further preferably 25 or more, and 2000 or less. The wiping sheet according to any one of <1> to <18>, wherein the amount is preferably 1500 or less, and more preferably 1000 or less.
<20>
The fineness of the first fiber is preferably 0.5 dtex or more, more preferably 1 dtex or more, further preferably 1.2 dtex or more, and the upper limit thereof is preferably 3 dtex or less. , 2.5 dtex or less, more preferably 2 dtex or less, the wiping sheet according to any one of <1> to <19>.

<21>
The wiping sheet according to any one of <1> to <20>, wherein both the first fiber and the second fiber are synthetic fibers.
<22>
The wiping sheet according to any one of <1> to <21>, which has a substantially rectangular shape.
<23>
A pattern concave portion and a pattern convex portion forming the uneven portion of the macroscopic pattern are formed on one surface of the wiping sheet, and the boundary line between the pattern concave portion and the pattern convex portion is viewed macroscopically. The wiping sheet according to any one of <1> to <22>, which has a curved portion.
<24>
The wiping sheet according to <23>, wherein the other surface is flat when the uneven portion is formed on one surface.

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]
As the first fiber, a deformed fiber having a multi-leaf shape in cross section of the fiber made of a thermoplastic resin (see FIG. 2 (e)) was used to perform water flow entanglement to produce a fiber aggregate. The constituent fibers of the fiber aggregate are multileaf fibers (made of PET, fineness 1.7 dtex, average fiber diameter 13.5 μm) as the first fibers and round fibers (made of PP, fineness 7.) as the second fibers. 0 × 10 ^-3 dtex, average fiber diameter 1 μm) was used. The fiber composition of the fiber aggregate was assumed to be contained in a mass ratio of first fiber: second fiber = 90:10. After molding the size of the fiber aggregate to 285 mm × 205 mm, it was ^{impregnated with a cleaning liquid of 290 g / m 2} to obtain a desired wet wiping sheet. As the cleaning liquid, a 0.1% by mass aqueous solution of a surfactant (Emargen (registered trademark) 108, manufactured by Kao Corporation) was used. The basis weight of the wiping sheet was 67 g / m ² .

[Example 2]
Examples except that a perfect circular fiber (made of PP, fineness 1.7 × 10 ^-1 dtex, average fiber diameter 5.0 μm) different from the perfect circular fiber used in Example 1 was used as the second fiber. A wet wiping sheet was produced in the same manner as in 1. That is, the wiping sheet of this embodiment contains a multi-leaf fiber as the first fiber and a perfect circular fiber as the second fiber.

[Comparative Example 1]
As the first fiber, a fiber aggregate was produced by performing water flow entanglement using only a fiber having a perfectly circular cross-sectional shape of a fiber made of a thermoplastic resin. The round fiber as the first fiber was made of PET, had a fineness of 1.45 dtex, and had an average fiber diameter of 11.5 μm. Other conditions were the same as in Example 1, and a wet wiping sheet was produced. The wiping sheet of this comparative example does not contain a second fiber.

[Comparative Example 2]
As the first fiber, a fiber aggregate was produced by performing water flow entanglement using only a deformed fiber having a multi-leaf shape in the cross section of the fiber made of a thermoplastic resin. The multileaf fiber as the first fiber was made of PET, had a fineness of 1.7 dtex, and had an average fiber diameter of 13.5 μm. Other conditions were the same as in Example 1, and a wet wiping sheet was produced. The wiping sheet of this comparative example does not contain a second fiber.

[Comparative Example 3]
As the second fiber, a fiber aggregate was produced by performing water flow entanglement using only a small-diameter fiber having a perfectly circular cross-sectional shape of the fiber made of a thermoplastic resin. The round fiber as the second fiber was made of PP, had a fineness of 7.0 × 10 ^-3 dtex, and had an average fiber diameter of 1 μm. Other conditions were the same as in Example 1, and a wet wiping sheet was produced. The wiping sheet of this comparative example does not contain the first fiber.

[Comparative Example 4]
In this comparative example, water flow entanglement is performed using the first and second fibers whose cross-sectional shapes are both perfectly circular, and the abundance ratio of the second fiber is higher than that of the second surface on the first surface. Manufactured a fiber aggregate that was elevated in. The constituent fibers of the fiber aggregate are a perfect circular fiber (made of PET, fineness 1.45 dtex, average fiber diameter 11.5 μm) as the first fiber and a perfect circular fiber (made of PP, fineness 7.0) as the second fiber. × 10 ^-3 dtex, average fiber diameter of about 1 μm) was used. The fiber composition of the fiber aggregate contained the first fiber: the second fiber = 90:10 in a mass ratio. Other conditions were the same as in Example 1, and a wet wiping sheet was produced. That is, in the wiping sheet of this comparative example, the second fiber is mainly present on the first surface, and the first fiber is mainly present on the second surface. The abundance ratio (area ratio) of the second fiber on the first surface was 73%, and the abundance ratio (area ratio) of the second fiber on the second surface was 10%.

[Evaluation of tensile elastic modulus]
The tensile elastic modulus was measured for the wiping sheets of Examples and Comparative Examples. Specifically, a tensile strength tester (manufactured by Shimadzu Corporation, AG-IS 100N) is used to prepare a dry sample having a length of 150 mm and a width of 30 mm in the length direction at a span of 100 mm and a speed of 300 mm / min. The tensile strength (N / mm) and the displacement (mm) at that time were measured. The tensile elastic modulus (N / mm ² ) was calculated by subtracting the difference in displacement in these tensile strengths from the difference in tensile strength between 0N / mm and 0.17N / mm. The higher the tensile elastic modulus, the higher the sheet strength. The results are shown in Table 1.

[Evaluation of fine particle collection performance]
In this evaluation, 7 types of test powder (grains) specified in JIS Z 8901 are used as a model for fine particle stains on a flooring floor (DAG floor, manufactured by Kitae Co., Ltd.) with a length (cleaning direction) of 90 cm and a width of 90 cm. 11 kinds of test powders (particle size: 1 to 8 μm) or 11 kinds of test powders (diameter: 5 to 75 μm) or 11 kinds of test powders (particle size: 1 to 8 μm) were sprayed in an area of 15 cm to 30 cm in length and 90 cm in width from the front in the wiping direction in an area of 0.1 g. The wiping sheet of the example or the comparative example was wiped against this flooring by reciprocating twice in the wiping direction every 30 cm in width. This operation was performed for 6 sets. As for the direction of the sheet at the time of wiping, the width direction Y in FIG. 4 was set to the same direction as the wiping direction. The change in sheet mass before and after wiping was measured, and the fine particle collection performance was evaluated according to the following criteria. The results are shown in Table 1.

<Calculation formula>
Fine particle dust collection rate (%) = 100 × ((mass of wiping sheet after wiping [g])-(mass of wiping sheet before wiping [g])) /0.1 [g])
<Collection performance>
⊚: The fine particle dust collection rate is 90% or more, and the fine particle dust collection performance is very high.
◯: The fine particle dust collection rate is 70% or more and less than 90%, and the fine particle dust collection performance is high.
Δ: The fine particle dust collection rate is 50% or more and less than 70%, and the fine particle dust collection performance is slightly low.
X: The fine particle dust collection rate is less than 50%, and the fine particle dust collection performance is low.

[Evaluation of hair collection performance]
In this evaluation, a flooring floor (DAG floor, manufactured by Kitakei Co., Ltd.) in which 20 10 cm hairs were sprayed per 1 tatami mat (1820 mm × 910 mm) was wiped for 6 tatami mats. As for the direction of the sheet at the time of wiping, the width direction Y in FIG. 4 was set to the same direction as the wiping direction. The number of hairs collected on the wiping sheet after wiping was measured, and the hair collection performance was evaluated according to the following criteria. The results are shown in Table 1.

<Calculation formula>
Hair collection rate (%) = 100 x (Number of hairs collected on the wiping sheet [lines]) / (Number of sprayed hairs [lines])
<Collection performance>
⊚: The hair collection rate is 80% or more, and the hair collection performance is very high.
◯: The hair collection rate is 60% or more and less than 80%, and the hair collection performance is high.
Δ: The hair collection rate is 40% or more and less than 60%, and the hair collection performance is slightly low.
X: The hair collection rate is less than 40%, and the hair collection performance is low.

[Evaluation of sustained release of cleaning solution]
^{A load of 0.16 kN / m 2} is applied to the wet wiping sheets of Examples and Comparative Examples, and a flooring floor (Combit New Advance 101, manufactured by Wood One Co., Ltd.) is used as a wiping target surface at a wiping speed of 1 m / s, and is 20 tatami mats. Wiping was performed continuously for 1 minute ( ^{equivalent to 32.4 m 2).} From the liquid release amount (g) for each tatami mat, how much was released at each wiping area with respect to the initial impregnation amount of the cleaning liquid was measured, and the sustained release property of the cleaning liquid was evaluated according to the following criteria. The results are shown in Table 1. The higher the cleaning solution release rate, the better the sustained release property.

<Evaluation>
⊚: The cleaning liquid release rate at the time of 20 tatami mats of wiping area is 70% or more.
◯: The cleaning liquid release rate at the time of 20 tatami mats of wiping area is 50% or more and less than 70%.
Δ: The cleaning liquid release rate at the time of the wiping area of 20 tatami mats is 30% or more and less than 50%.
X: The cleaning liquid release rate at the time of the wiping area of 20 tatami mats is less than 30%.

As shown in Table 1, the wiping sheet of the present invention contains irregularly shaped fibers and fibers having a diameter smaller than the fibers as its constituent fibers, so that the sheet strength is high, and fine particle stains and fiber stains such as hair are stained. It can be seen that it has a high collection performance. It can also be seen that the wiping sheet of the present invention has a high sustained release property of the cleaning liquid and is capable of wiping over a wide range when it is in a wet mode.

According to the present invention, it is possible to provide a wiping sheet having both high strength and high dirt collection performance.

Claims (23)

It comprises at least a first fiber and a second fiber having a diameter smaller than that of the fiber, and has a fiber aggregate formed by entwining these fibers, and is located on the first surface and the opposite side of the first surface. A wiping sheet having a second surface and
The abundance ratio of the second fiber is higher on the first surface than on the second surface.
A wiping sheet in which at least the first fiber is a deformed fiber whose cross section is non-circular. The wiping sheet according to claim 1, wherein both the first fiber and the second fiber are the deformed fibers. The wiping sheet according to claim 1 or 2, wherein the deformed fiber has a convex polygonal shape or a regular polygonal shape in its cross section. The wiping sheet according to any one of claims 1 to 3, wherein the deformed fiber has a multi-leaf shape in its cross section. The wiping sheet according to any one of claims 1 to 4, which is composed of only the fiber aggregate. The wiping sheet according to any one of claims 1 to 4, further comprising another sheet material or other member in addition to the fiber assembly. The wiping sheet according to any one of claims 1 to 6, wherein the abundance ratio of the second fiber on the first surface is 40% or more and 100% or less in terms of area ratio. The wiping sheet according to any one of claims 1 to 7, wherein the abundance ratio of the second fiber on the second surface is 1% or more and 60% or less in terms of area ratio. The wiping sheet according to any one of claims 1 to 8, wherein the abundance ratio of the first fiber on the first surface is 0% or more and 60% or less in terms of area ratio. The wiping sheet according to any one of claims 1 to 9, wherein the abundance ratio of the first fiber on the second surface is 50% or more and 100% or less in terms of area ratio. The wiping sheet according to any one of claims 1 to 10, wherein the constituent fibers of the fiber aggregate are not fused to each other. The wiping sheet according to any one of claims 1 to 11, wherein the cleaning liquid is supported on the fiber assembly. The wiping sheet according to claim 12, wherein the cleaning liquid is an aqueous solution containing an additive. The additive is at least one selected from the group consisting of surfactants, bactericides, fragrances, fragrances, deodorants, pH adjusters, alcohols, abrasive particles, gloss enhancers and thickeners. Item 13. The wiping sheet according to Item 13. The wiping sheet according to any one of claims 1 to 14, wherein the first fiber is a fiber made of a thermoplastic resin. The wiping sheet according to any one of claims 1 to 15, wherein the tensile elastic modulus is 1.3 × 10 ^-3 N / mm ^{2 or more.} The wiping sheet according to any one of claims 1 to 16, wherein the tensile elastic modulus is 1.3 × 10 ^-3 N / mm ² or more and 5.0 × 10 ^-3 N / mm ^{2 or less.} The wiping sheet according to any one of claims 1 to 17, wherein the ratio of the fineness of the first fiber to the fineness of the second fiber is 10 or more and 2000 or less. The wiping sheet according to any one of claims 1 to 18, wherein the ratio of the fineness of the first fiber to the fineness of the second fiber is 15 or more and 1500 or less. The wiping sheet according to any one of claims 1 to 19, wherein the fineness of the first fiber is 0.5 dtex or more and 3 dtex or less. The wiping sheet according to any one of claims 1 to 20, wherein both the first fiber and the second fiber are synthetic fibers. A pattern concave portion and a pattern convex portion forming the uneven portion of the macroscopic pattern are formed on one surface of the wiping sheet, and the boundary line between the pattern concave portion and the pattern convex portion is viewed macroscopically. The wiping sheet according to any one of claims 1 to 21, which has a curved portion. The wiping sheet according to claim 22, wherein the other surface is flat when the uneven portion is formed on one surface.

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