WO2020071250A1

WO2020071250A1 - Wiping sheet

Info

Publication number: WO2020071250A1
Application number: PCT/JP2019/037998
Authority: WO
Inventors: 翔太郎百合野; 行人成田
Original assignee: 花王株式会社
Priority date: 2018-10-02
Filing date: 2019-09-26
Publication date: 2020-04-09
Also published as: SG11202102900RA; TWI839394B; JPWO2020071250A1; TW202020250A; CN112788975A

Abstract

This wiping sheet (1) comprises a fiber aggregate (1A) including at least first fibers (11) and second fibers (12) that are finer than the first fibers, the fiber aggregate (1A) being obtained by entangling of these fibers, and the wiping sheet having a first surface (1F) and a second surface (1R) positioned on the opposite side from the first surface (1F). The proportion at which the second fibers (12) are present is higher in the first surface (1F) than in the second surface (1R). At least the first fibers (11) are irregularly shaped fibers in which a cross-section is non-circular. It is also suitable for a washing liquid to be supported by the fiber aggregate (1A). It is also suitable for the first fibers (11) to comprise a thermoplastic resin. It is also suitable for the tensile modulus of elasticity to be 1.3 × 10^-3 N/mm² or higher.

Description

Wiping sheet

The present invention relates to a wiping sheet.

繊維 Fibers made from a thermoplastic resin are used in various applications in the form of a nonwoven fabric in which the fibers are entangled. For example, Patent Document 1 describes a cleaning cloth provided with a fiber entangled body mainly composed of ultrafine fibers having an average fiber diameter of 0.3 to 3.0 μm and having an irregular cross section. The document describes that this cleaning cloth is used for cleaning the surface of a magnetic recording medium substrate.

Patent Document 2 discloses a nonwoven fabric composed of 20 to 80% by mass of a polyester fiber having a multi-lobal flat cross section and 20 to 80% by mass of a cellulosic fiber. This non-woven fabric has high liquid absorbing and absorbing power and releasability of liquids such as water and chemicals, and has both appropriate bulkiness and flexibility, so it can be used for personal wiping and cosmetics. It is described in.

JP 2013-124422 A US 2015/359400 A1

The present invention relates to a wiping sheet including at least a first fiber and a second fiber having a smaller diameter than the fiber, and including a fiber aggregate in which these fibers are entangled. The wiping sheet has a first surface and a second surface opposite to the first surface. In the wiping sheet, the proportion of the second fibers present is higher on the first surface than on the second surface. In the wiping sheet, at least the first fiber is a modified fiber whose cross section is non-circular.

FIG. 1 is a schematic sectional view showing an embodiment of the wiping sheet of the present invention. FIGS. 2A and 2E are schematic perspective views of the cross-sectional shape of the modified fiber used in the wiping sheet of the present invention. FIGS. 3A to 3C are enlarged plan views of the cross-sectional shapes of the modified fibers in FIGS. 1B, 1D, and 1E. FIG. 4 is a schematic view showing one embodiment of the concave and convex portion of the macroscopic pattern on the first surface of the wiping sheet of the present invention. FIG. 5 is a schematic view of a manufacturing apparatus suitably used for manufacturing the wiping sheet of the present invention. FIG. 6 is a schematic view of an uneven portion forming member for forming the uneven portion of the macroscopic pattern.

Detailed description of the invention

The cleaning cloth and the nonwoven fabric described in Patent Literatures 1 and 2 are intended for cleaning the surface of a substrate, or for wiping or cosmetics for a person, and collecting dirt when a floor or the like is cleaned. Is not disclosed at all. Further, a nonwoven fabric or the like containing ultrafine fibers has insufficient strength, and as a result, the sheet is likely to break during use.

Accordingly, the present invention is directed to a wiping sheet that overcomes the disadvantages of the prior art.

Hereinafter, the wiping sheet of the present invention will be described based on a preferred embodiment. In the present invention, "wiping" includes both the meaning of cleaning and wiping, for example, cleaning of buildings such as floors, walls, ceilings and columns, cleaning of fittings and fixtures, wiping of articles, This includes wiping of the body and equipment related to the body. In the present specification, the term “wiping sheet” simply refers to a sheet carrying a cleaning liquid and a sheet not carrying a cleaning liquid, depending on the context.

The wiping sheet includes a first fiber and a fiber aggregate including at least a second fiber having a smaller diameter than the first fiber. The first fiber and the second fiber are the first fiber, the second fiber, and the first fiber and the second fiber entangled to form the fiber aggregate. That is, the fiber aggregate used for the wiping sheet is a fiber aggregate mainly composed of entanglement of the first and second fibers. The wiping sheet may be composed of only the fiber aggregate, or may include, in addition to the fiber aggregate, another sheet material and / or another member. The wiping sheet of the present invention may be a fiber aggregate that does not carry a cleaning liquid (hereinafter, this embodiment is also referred to as a “dry type”), or may be a fiber aggregate that carries a cleaning liquid (hereinafter, referred to as a “dry type”). This mode is also referred to as “wet”.)

FIG. 1 is a cross-sectional view of a fiber assembly provided in the wiping sheet of the present invention. As shown in the figure, the fiber aggregate 1A in the wiping sheet 1 is configured to include a first fiber 11 and a second fiber 12 having a smaller diameter than the first fiber. 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, the wiping sheet 1 mainly includes a second fiber 12 which is a fiber having a small fiber diameter on a first surface 1F in FIG. 1, and a first fiber 11 on a second surface 1R. Is mainly present. The first surface 1F serves as a wiping surface when the wiping sheet is used. Note that “mainly present” means that when the wiping sheet 1 is viewed in a vertical cross section along the thickness direction Z, the ratio of any fiber present in the above-described surface is the highest.

The proportion of the second fibers 12 occupied by the first surface 1F is preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more, expressed as an area ratio. Also, it is preferably at most 100%, more preferably at most 90%, even more preferably at most 85%. The abundance ratio of the second fibers 12 in the first surface 1F is preferably 40% or more and 100% or less, more preferably 50% or more and 90% or less, and more preferably 60% or more. More preferably, it is at most 85%. By having such an abundance ratio, it is possible to enhance the performance of collecting fine particle dirt with a dense and low porosity structure formed by the fine fibers, and to enhance the sheet strength during use. In addition, the sustained release of the cleaning solution in the wet mode can be enhanced.

The abundance ratio of the first fibers 11 on the first surface 1F is preferably 0% or more, more preferably 1% or more, still more preferably 5% or more, expressed as an area ratio. Also, it is preferably at most 60%, more preferably at most 40%, even more preferably at most 35%. The proportion of the first fibers 11 occupied by the first fibers 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 more preferably 5% or more. More preferably, it is 35% or less. By having such an abundance ratio, a high porosity structure formed by the large-diameter fibers can improve the performance of collecting fiber stains such as hair and enhance the sheet strength during use. In addition, the sustained release of the cleaning solution in the wet mode can be enhanced.

Similarly, the proportion of the second fibers 12 on the second surface 1R occupied by the second fibers 12 is preferably 1% or more, more preferably 3% or more, and more preferably 5% or more in terms of area ratio. Is more preferably 60% or less, more preferably 40% or less, and even more preferably 35% or less. The proportion of the second fibers 12 occupied by the second surface 1R in the area ratio is preferably 1% or more and 60% or less, more preferably 3% or more and 40% or less, and more preferably 5% or more. More preferably, it is 35% or less.

Similarly, the proportion of the first fibers 11 occupying the second surface 1R is preferably 50% or more, more preferably 65% or more, and more preferably 70% or more, expressed in terms of area ratio. Is more preferably 100% or less, more preferably 90% or less, and even more preferably 87% or less. The abundance ratio of the first fibers 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 more preferably 70% or more. More preferably, it is 87% or less.

存在 The 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 microscope. Specifically, the image data is acquired with the first surface 1F or the second surface 1R as the observation target. Using an image processing software such as ImageJ, a threshold is set for each of the obtained images at the lightness boundary between the first fiber and the second fiber, and the lightness is binarized. Thereafter, the area having each color is calculated, and the area ratio of each fiber is calculated.

When the wiping sheet considers a virtual surface parallel to the first surface 1F, the existence ratio of the second fiber 12 in the virtual surface is expressed by an area ratio, and is a thickness on the opposite side of the first surface 1F. It is preferred that it decreases stepwise, continuously, or a combination thereof in the direction Z. In particular, an imaginary plane parallel to the first surface 1F for a portion extending from 50% to 100% of the thickness of the wiping sheet along the wiping sheet thickness direction Z with the second surface 1R as a reference (zero surface). The sheet strength and the dirt collecting property can be enhanced by setting the presence ratio of the second fibers 12 in the range of 50% or more and 100% or less in terms of area ratio. Further, the sustained release property of the cleaning liquid in the wet mode can be enhanced.

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

ワイ In the wiping sheet of the present invention, at least the first fibers 11 having a large diameter are modified fibers. Irregular fibers are those whose cross section is non-circular. 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 collection performance, at least the first fiber 11 having a large diameter is preferably an irregular fiber, and both the first fiber and the second fiber are irregular fibers. More preferably.

Examples of the modified fibers having the cross-sectional shape of such fibers include, for example, triangles shown in FIG. 2 (a), convex polygons such as quadrangular, pentagonal and hexagonal or regular polygons, and FIG. 2 (b). Examples include cross-sectional shapes such as a star polygon, an elliptical shape shown in FIG. 2C, a W-shaped shape shown in FIG. 2D, and a multi-leaf shape shown in FIG. There is no particular limitation as long as the effects of the invention are exhibited.

The first fiber 11 is a modified fiber having preferably at least one, more preferably two or more, and more preferably three or more convex portions having a sharp apex in the cross-sectional shape thereof. The sharp peak is defined as (a) one straight line and one straight line when the contour of the convex portion in the cross-sectional shape of the deformed fiber is defined by, for example, (a) two non-parallel straight lines intersecting with each other. And (c) a case where two curves intersect with each other. For example, the deformed fiber shown in FIG. 2A has three sharp peaks, the deformed fiber shown in FIG. 2B has six sharp peaks, and the deformed fiber shown in FIG. It has eight tops. In the present invention, one type of modified fiber may be used alone, or two or more types of modified fibers having different cross-sectional shapes may be used in combination.

The wiping sheet of the present invention has a high tensile modulus due to the fact that the constituent fibers include irregular fibers. In light of increasing the strength of the wiping sheet, the tensile elastic modulus of the wiping sheet is preferably equal to or greater than 1.3 × 10 ⁻³ N / mm ^{2 and} equal to or greater than 1.4 × 10 ⁻³ N / mm ^2. Is more preferably 1.5 × 10 ⁻³ N / mm ² or more. Although the upper limit of the tensile modulus is not particularly limited, it is practically 5.0 × 10 ⁻³ N / mm ² or less. The tensile elastic modulus can be determined from, for example, a difference between two tensile strengths (N / mm) and a difference between displacements (mm) in these tensile strengths. The measuring method will be described in detail in Examples described later.

から From the viewpoint of achieving a high level of both sheet strength and dirt collection efficiency, the fineness (dtex) of the first fiber is preferably 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 preferably 25 or more. More preferably, it is preferably 2000 or less, more preferably 1500 or less, even more preferably 1000 or less.

From the same viewpoint, the fineness of the first fibers 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 upper limit is preferably 3 dtex or less, more preferably 2.5 dtex or less, even more preferably 2 dtex or less.

From the same viewpoint, the fineness of the second fiber included in the wiping sheet is preferably 1.5 × 10 ⁻³ dtex or more, more preferably 2.5 × 10 ⁻³ dtex or more, and more preferably 4 × 10 ⁻³ dtex or more. More preferably, it is not less than 0.5 × 10 ⁻³ dtex. 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 ⁻² dtex or less. Is more preferable.

The first fibers 11 and the second fibers 12 constituting the wiping sheet 1 may be any of synthetic fibers and natural fibers. However, from the viewpoint of easy molding and production efficiency of the fibers, at least the first fibers 11 and the second fibers 12 may be used. 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. An acrylic resin such as polymethyl methacrylate, a fluororesin such as polyperfluoroethylene, and the like can be given. Examples of the natural fiber include various cellulose fibers, for example, hydrophilic fibers such as pulp, cotton, rayon, lyocell, and tencel. These fibers can be used alone or in combination of two or more.

から From the viewpoint of increasing the degree of freedom of the constituent fibers and improving the dirt collection performance, it is preferable that all the fibers constituting the wiping sheet are entangled without being fused to each other. By having such a configuration, it is possible to enhance the dirt collection performance while maintaining the strength of the sheet, and when the wiping sheet is used in a wet mode, the cleaning liquid per unit area is supported. The advantage of increased volume is also provided.

繊維 The fiber length of the first fiber depends on the method of 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 even more 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 method such as a spunbond method, a melt blown method, and an electrospinning method (electrospinning method). From the viewpoint of further increasing the production efficiency of the fine fiber, it is preferable that at least the second fiber is a synthetic fiber made of a thermoplastic resin and produced by an electrospinning method.

Of the line segments crossing the cross section of the deformed fiber, the length of the longest line segment was A, and the length of the longest line segment orthogonal to the line segment and crossing the cross section was B. Sometimes (see FIGS. 3A to 3C), the ratio (A / B) of the length A to the length B is preferably 1.2 or more, more preferably 1.5 or more. It is more preferably 2 or more, and the upper limit is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less. Specifically, the value of A / B is preferably 1.2 or more, 5 or less, more preferably 1.5 or more and 4 or less, and even more preferably 2 or more and 3 or less. By having such a configuration, the fibers constituting the wiping sheet are easily entangled with fiber stains such as hair, and these stains can be hooked on the fibers and removed from the surface to be wiped.

With respect to the above-described length A and length B, examples of cross-sectional shapes other than the shapes shown in FIGS. 3A to 3C are as follows. 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 drawn from one vertex to one side. Further, in a modified fiber whose cross-sectional shape is elliptical (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 modified fibers having different cross-sectional shapes, the lengths A and B are the average of A and the average of B measured for all types of modified fibers. That is.

The length A is preferably 1 μm or more, and more preferably 5 μm or more on condition that the above-mentioned A / B range is satisfied, from the viewpoint of both the operability at the time of wiping and the collecting property of dirt. More preferably, it is more preferably at least 10 μm, and the upper limit is preferably at most 80 μm, more preferably at most 50 μm, and preferably at most 25 μm. 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. The upper limit is preferably 40 μm or less, more 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 plurality of convex portions P and the concave portions located between the adjacent convex portions P. In the case of a shape having R, the length of a line segment connecting the vertices of adjacent convex portions P is C, and the length of a perpendicular line drawn from the line segment to the lowest position of the concave portion R is D (See FIGS. 3A to 3C), the value of C / D is preferably 0.1 or more, more preferably 1 or more, still more preferably 2 or more, and the upper limit thereof. Is preferably 5 or less, more preferably 4 or less, and still more preferably 3 or less. By having such a configuration, the surface area of the single fiber increases and the contact area with the dirt increases, so that the dirt collecting performance 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 arbitrarily selected adjacent convex portions P is different, the value of C for calculating the value of C / D is all The average value of the values of C is used. Similarly, when the length of the perpendicular line in the concave portion R arbitrarily selected is different from D, the value of D for calculating the value of C / D is an average value of all the values of D. In the following description, when a value of C and D is referred to, the value is an average value of C and D.

From the viewpoint of improving the operability and the collection efficiency of dirt during wiping, the length C is preferably 0.1 μm or more, and more preferably 0.5 μm or more, provided that the above-described C / D range is satisfied. More preferably, it is more preferably 1 μm or more, and the upper limit is preferably 20 μm or less, more 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 on condition that the above-mentioned C / D range is satisfied. Is more preferable, and the upper limit thereof is preferably 20 μm or less, more 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 assembly was cut using a razor or the like while maintaining the cross-sectional shape of the fiber, and the cross-section was vacuum-deposited with Pt. Using a scanning electron microscope (JSM-IT100, manufactured by JEOL Ltd.), the cross section of the Pt-deposited fiber assembly was observed at a magnification of 500 to 1000 times, and the above-mentioned fiber cross section was measured using the attached software length measurement tool. The lengths A to D were measured respectively.

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

When other fibers are included in the wiping sheet of the present invention, the fineness of the fibers is preferably 0.6 dtex or more, and more preferably 1.0 dtex or more, from the viewpoints of operability and dirt collection efficiency during wiping. More preferably, it is more preferably 1.2 dtex or more. Further, it is preferably at most 4.0 dtex, more preferably at most 3.5 dtex, even more preferably at most 3.0 dtex.

In light of appropriate strength of the wiping sheet, the basis weight of the fiber aggregate constituting the wiping sheet is preferably equal to or greater than 40 g / m ^2, more preferably equal to or greater than 45 g / m ^{2, and} further preferably equal to or greater than 50 g / m ^2. 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. It is more preferably 80 g / m ² or less.

From the same viewpoint, the thickness of the wiping sheet is preferably 0.5 mm or more under a load of 40 N / m ² , more preferably 1.0 mm or more, and the upper limit is 2 mm under the same load. It is preferably at most 0.5 mm, more preferably at most 3 mm.

The wiping sheet may use the fiber aggregate as it is (a so-called dry mode) at the time of wiping, or may use the cleaning liquid applied to the fiber assembly, sprayed, supported or impregnated (a so-called wet mode). May be. These modes can be selected according to the type of dirt attached to the surface to be wiped and the physical properties of the object to be wiped. From the viewpoint of increasing the cleaning efficiency on the surface to be cleaned, it is preferable that the fiber assembly constituting the wiping sheet carry a cleaning liquid. That is, the wiping sheet of the present invention is preferably of a wet type. Since the fiber aggregate contains deformed fibers, the voids between the fibers can be increased, and as a result, the liquid retention of the cleaning liquid in the wiping sheet is improved while increasing the dirt collection performance. There are also benefits.

At the time of wiping, when the wiping sheet is used in a wet mode, as the cleaning liquid carried on the sheet, water alone or an aqueous solution containing an additive, such as a general composition used for a wet wiping sheet, is used. be able to. As the additive used in the cleaning liquid, at least one selected from the group consisting of a surfactant, a bactericide, a fragrance, a fragrance, a deodorant, a pH adjuster, an alcohol, abrasive particles, a gloss imparting agent and a thickener. Is mentioned.

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

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

The concavo-convex portions of the macroscopic pattern are not limited to the macroscopic pattern shown in the figure. For example, the macroscopic pattern shown in Japanese Patent Application Laid-Open No. 2017-113282 and a graphic such as a straight line, a curve, a circle, and a polygon are appropriately combined. It may be a macroscopic pattern. Note that the macroscopically curved shape constitutes a pattern uneven portion except for a curve constituting a micro-scale fine hole and a curve constituting a drainage hole having a diameter of about 1.5 to 2 mm. This means that it is possible to visually confirm that a part of the side of the figure is a curve, and from such a viewpoint, the area of each pattern convex portion 4 surrounded by the pattern concave portion 3 becomes 300 mm ² or more. Thus, it is preferable to form the pattern concave portions 3 and the pattern convex portions 4. Providing such a macroscopic pattern of irregularities also has the advantage of improving the design of the wiping sheet itself.

The wiping sheet of the present invention may be constituted by a fiber assembly in which the boundary of the existing region between the first fiber and the second fiber in the sheet thickness direction is not clear when focusing on one fiber assembly. Alternatively, it may be constituted by a fiber aggregate having a two-layer structure of a layer containing the first fibers and a layer containing the second fibers. Further, the wiping sheet of the present invention is composed of a fiber aggregate having a multilayer structure of three or more layers including a layer containing a first fiber, a layer containing a second fiber, and a layer containing another fiber. Is also good.

The wiping sheet of the present invention may be composed of only one fiber aggregate (irrespective of a single layer or a multilayer) containing deformed fibers, or a first fiber aggregate containing first and second fibers. And a multi-ply laminate structure in which the second fiber aggregate with or without the deformed fiber or a sheet material other than the fiber aggregate is laminated. Examples of the sheet material include a nonwoven fabric, a 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 aggregate constituting the sheet. When a scrim net is provided, it is preferable that the scrim net is arranged in the central region in the thickness direction of the fiber assembly. The scrim net can be integrally entangled with the deformed fiber constituting the fiber assembly, and may be in the form of a net, a grid, a strand, or the like.

樹脂 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; A vinylidene-based 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 diameter of the scrim net (diameter in the cross section) can be appropriately adjusted according to the degree of entanglement of the fiber, but is 10 μm or more. Is preferably 500 μm or more, more preferably 2000 μm or less, and even more preferably 1000 μm or less. The wire diameter of the scrim net may be partially different or the same, and when the wire diameter is partially different, the wire diameter of the scrim is taken to be the average value. In addition, the basis weight of the scrim net is preferably 1 g / m ² or more, more preferably 3 g / m ² or more, preferably 20 g / m ² or less, and further preferably 10 g / m ² or less.

While the above is an explanation of an embodiment of the wiping sheet of the present invention, a preferred method of manufacturing the wiping sheet will be described below with reference to FIG. FIG. 5 shows a manufacturing apparatus 10 suitably used for manufacturing a wiping sheet. The manufacturing apparatus 10 includes a web forming unit 20, a first hydroentanglement unit 30, and a second hydroentanglement unit 40 in this order along the transport direction (MD direction). The present manufacturing method includes a step of forming a fiber aggregate including deformed fibers by hydroentanglement, and, if necessary, 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 conveying direction (MD direction) matches the sheet width direction Y, and the direction orthogonal to the conveying direction matches the sheet longitudinal direction X.

First, the web of the first fibers 11 is fed out from the card machine 21 in the web forming section 20 via the guide roll 22. When the wiping sheet is provided with a scrim net, the scrim net 15 is fed from the scrim roll 25 together with the web of the first fibers 11. The web of the first fibers 11 and the scrim net are stacked by these feedings.

Next, in the first hydroentanglement section 30, the web of the first fibers 11 (or the laminate of the web of the first fibers 11 and the scrim net 15) is moved in the MD direction by the first support belt 32 through which water can pass. While being conveyed, the water is entangled by a high-pressure water jet ejected from the first water jet nozzle 31 (first entanglement step). Through this step, the first fibers 11 are entangled with each other to form an entangled body of the first fibers 11. In the case where the scrim net is provided, by this step, the first fibers 11 are entangled with each other, and the first fibers 11 and the scrim net 15 are integrally entangled, and the scrim net is arranged. An entangled body of the first fibers 11 is formed. In this step, the water pressure blown from the first water stream 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 fibers 11 The transport speed in the MD direction is preferably 2 m / min or more and 10 m / min or less, more preferably 4 m / min or more and 8 m / min or less.

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

After the second hydroentanglement step, the fiber assembly 1A may be used as it is as a wiping sheet 1 of a dry type or a wet type, and if necessary, 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 a dry or wet mode.

For example, in the case where an uneven portion having a macroscopic pattern is formed on the surface (first surface 1F in FIG. 1) of the fiber assembly 1A where the second fibers 12 mainly exist, the uneven portion shown in FIG. The forming member 50 is arranged on the surface of the fiber assembly 1A on which the second fibers 12 mainly exist, and a high-pressure water flow is blown from the opposite surface (the second surface 1R in FIG. 1). Thereby, the pattern concave portion 3 and the pattern convex portion 4 complementary to the concave and convex shape of the concave and convex portion forming member 50 can be formed on the first surface 1F of the fiber assembly 1A. The water pressure blown to the fiber assembly 1A and the transport speed of the fiber assembly can be in the same range as in the above-described entanglement step.

The fiber assembly 1A manufactured as described above may be used as a dry wiping sheet as it is, for example, after being formed into a rectangular shape as shown in FIG. 4, and the cleaning solution is carried on the fiber assembly 1A ( Supporting step), it can also be used as a wet wiping sheet. In the washing liquid carrying step, the carrying amount of the washing liquid carried on the fiber assembly 1A is preferably 1 g / sheet or more when the dimensions of the wiping sheet 1 are 285 mm × 205 mm, for example, as described in Examples below. 10 g / sheet or more is more preferable, 40 g / sheet or less is preferable, and 25 g / sheet or less is more 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 manner is attached to a cleaning tool such as a wiping sheet alone or a wiper, and a floor, a building such as a wall surface, a cupboard, a window glass, a mirror, a door, a door fitting and other fittings, It can also be used for furniture such as rugs, carpets, dining tables, kitchens, toilets, body cleaning, sanitary products, packaging, and the like.

Although the present invention has been described based on the preferred embodiments, the present invention is not limited to the above embodiments. In order to form a fiber aggregate including fibers other than the first and second fibers, for example, in the web forming unit 20, a second card machine is disposed, and a web of another fiber is formed from the card machine. May be fed out and laminated. Thereafter, by performing a confounding step, a fiber aggregate including other fibers in addition to the first fibers can be formed.

Regarding the above-described embodiment of the present invention, the following wiping sheet is further disclosed.
<1>
A fiber aggregate including at least a first fiber and a second fiber having a smaller diameter than the fiber is provided. The fiber aggregate is formed by entanglement of the fibers, and is located on a first surface and on a side opposite to the first surface. A wiping sheet having a second surface,
The proportion of the second fibers present is higher on the first surface than on the second surface,
A wiping sheet, wherein at least the first fiber is a modified fiber whose cross section is non-circular.

<2>
The wiping sheet according to <1>, wherein both the first fibers and the second fibers are the modified fibers.
<3>
The wiping sheet according to <1> or <2>, wherein the cross-sectional shape of the modified fiber is a convex polygon such as a triangle, a quadrangle, a pentagon, and a hexagon or a regular polygon.
<4>
The wiping sheet according to any one of the above <1> to <3>, wherein the modified fiber has a multi-lobed cross-sectional shape.
<5>
The wiping sheet according to any one of the above <1> to <4>, which is composed of only the fiber aggregate.
<6>
The wiping sheet according to any one of <1> to <4>, further including another sheet material or another member in addition to the fiber assembly.

<7>
The presence ratio of the second fibers on the first surface is preferably 40% or more, more preferably 50% or more, still more preferably 60% or more, expressed as an area ratio. , 100% or less, more preferably 90% or less, even more preferably 85% or less, the wiping sheet according to any one of the above <1> to <6>.
<8>
The presence ratio of the second fiber on the second surface is preferably 1% or more, more preferably 3% or more, still more preferably 5% or more, expressed as an area ratio. , 60% or less, more preferably 40% or less, and even more preferably 35% or less, the wiping sheet according to any one of the above <1> to <7>.
<9>
The proportion of the first fibers occupied by the first fibers on the first surface is preferably 0% or more, more preferably 1% or more, still more preferably 5% or more, expressed as an area ratio. , 60% or less, more preferably 40% or less, even more preferably 35% or less, the wiping sheet according to any one of the above <1> to <8>.
<10>
The proportion of the first fiber on the second surface occupied by the first fiber is preferably 50% or more, more preferably 65% or more, still more preferably 70% or more, expressed as an area ratio. Wiping sheet according to any one of <1> to <9>, wherein the wiping sheet is preferably 100% or less, more preferably 90% or less, and even more preferably 87% or less.

<11>
The wiping sheet according to any one of <1> to <10>, wherein the constituent fibers of the fiber assembly are not fused to each other.
<12>
The wiping sheet according to any one of <1> to <11>, wherein a cleaning liquid is carried 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 a surfactant, a bactericide, a fragrance, a fragrance, a deodorant, a pH adjuster, an alcohol, abrasive particles, a gloss imparting agent, and a thickener. The wiping sheet according to <13>.
<15>
The wiping sheet according to any one of <1> to <14>, wherein the first fibers are fibers made of a thermoplastic resin.

<16>
The wiping sheet according to any one of the above items <1> to <15>, having a tensile elasticity of 1.3 × 10 ⁻³ N / mm ² or more.
<17>
The tensile modulus is preferably at least 1.3 × 10 ⁻³ N / mm ^2, more preferably at least 1.4 × 10 ⁻³ N / mm ^{2, and} more preferably at least 1.5 × 10 ⁻³ N / mm ^2. / Mm ² or more, and preferably 5.0 × 10 ⁻³ N / mm ² or less, the wiping sheet according to any one of the above items <1> to <16>.
<18>
The wiping sheet according to any one of <1> to <17>, wherein a 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 2,000 or less. The wiping sheet according to any one of <1> to <18>, wherein the wiping sheet is preferably 1500 or less, more preferably 1,000 or less.
<20>
The fineness of the first fiber is preferably 0.5 dtex or more, more preferably 1 dtex or more, still more preferably 1.2 dtex or more, and the upper limit thereof is preferably 3 dtex or less. The wiping sheet according to any one of <1> to <19>, wherein the wiping sheet is more preferably 2.5 dtex or less, and further preferably 2 dtex or less.

<21>
The wiping sheet according to any one of <1> to <20>, wherein the first fibers and the second fibers are both synthetic fibers.
<22>
The wiping sheet according to any one of <1> to <21>, which has a substantially rectangular shape.
<23>
On one surface of the wiping sheet are formed a pattern concave portion and a pattern convex portion that constitute the concave and convex portion of the macroscopic pattern, and the boundary between the pattern concave portion and the pattern convex portion is macroscopically viewed. The wiping sheet according to any one of the above <1> to <22>, having 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 by way of examples. However, the scope of the present invention is not limited to such embodiments.

[Example 1]
As the first fiber, hydroentanglement was performed using a modified fiber (see FIG. 2 (e)) in which the cross-sectional shape of the fiber made of a thermoplastic resin was multilobal, to produce a fiber aggregate. The constituent fibers of the fiber assembly are multilobal fibers (made of PET, fineness of 1.7 dtex, average fiber diameter of 13.5 μm) as the first fibers, and perfect circular fibers (made of PP, fineness of 7.25) as the second fibers. 0 × 10 ⁻³ dtex, average fiber diameter 1 μm). The fiber composition of the fiber assembly included the mass ratio of first fiber: second fiber = 90: 10. After the fiber assembly was formed into a size of 285 mm × 205 mm, the cleaning solution was impregnated with 290 g / m ² to obtain a target wet wiping sheet. As the cleaning liquid, a 0.1% by mass aqueous solution of a surfactant (Emulgen (registered trademark) 108, manufactured by Kao Corporation) was used. The basis weight of the wiping sheet was 67 g / m ² .

[Example 2]
Except that a perfect circular fiber different from the perfect circular fiber used in Example 1 (made of PP, fineness: 1.7 × 10 ⁻¹ dtex, average fiber diameter: 5.0 μm) was used as the second fiber, Similarly to 1, a wet wiping sheet was produced. That is, the wiping sheet of the present embodiment includes multilobal fibers as the first fibers and true circular fibers as the second fibers.

[Comparative Example 1]
As the first fiber, only a fiber made of a thermoplastic resin and having a perfect circular cross section was subjected to hydroentanglement to produce a fiber aggregate. The perfect circular fiber as the first fiber was made of PET, had a fineness of 1.45 dtex and an average fiber diameter of 11.5 μm. The other conditions were the same as in Example 1, and a wet wiping sheet was manufactured. The wiping sheet of this comparative example does not include the second fiber.

[Comparative Example 2]
As the first fiber, the hydroentanglement was performed using only the deformed fiber having a multi-lobed cross-sectional shape of the fiber made of the thermoplastic resin to produce a fiber assembly. The multilobal 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. The other conditions were the same as in Example 1, and a wet wiping sheet was manufactured. The wiping sheet of this comparative example does not include the second fiber.

[Comparative Example 3]
As the second fiber, the hydroentanglement was performed using only a small-diameter fiber whose cross-sectional shape of the fiber made of a thermoplastic resin was a perfect circle, to produce a fiber assembly. The perfect circular fiber as the second fiber was made of PP, had a fineness of 7.0 × 10 ⁻³ dtex, and an average fiber diameter of 1 μm. The other conditions were the same as in Example 1, and a wet wiping sheet was manufactured. The wiping sheet of this comparative example does not include the first fiber.

[Comparative Example 4]
In this comparative example, the hydroentanglement is performed using the first and second fibers, both of which have a perfect circular cross-sectional shape, so that the proportion of the second fibers on the first surface is larger than that on the second surface. To produce a fiber assembly that is high. The constituent fibers of the fiber assembly include a perfect circular fiber (made of PET, fineness of 1.45 dtex, average fiber diameter of 11.5 μm) as the first fiber and a perfect circular fiber (made of PP, fineness of 7.0 as the second fiber). × 10 ⁻³ dtex, average fiber diameter of about 1 μm). The fiber composition of the fiber assembly included the first fiber: the second fiber = 90: 10 in a mass ratio. The other conditions were the same as in Example 1, and a wet wiping sheet was manufactured. That is, in the wiping sheet of this comparative example, the second fibers mainly exist on the first surface, and the first fibers mainly exist on the second surface. The existing ratio (area ratio) of the second fibers on the first surface was 73%, and the existing ratio (area ratio) of the second fibers on the second surface was 10%.

(Evaluation of tensile modulus)
The tensile modulus of the wiping sheets of the examples and the comparative examples was measured. In detail, using a tensile strength tester (AG-IS 100N, manufactured by Shimadzu Corporation), a dry-type sample having a length of 150 mm and a width of 30 mm was sampled in the length direction at a span of 100 mm and a speed of 300 mm / min. Then, the tensile strength (N / mm) and the displacement (mm) at that time were measured. The tensile modulus (N / mm ² ) was calculated by dividing the difference in displacement in tensile strength between the difference in tensile strength between 0 N / mm and 0.17 N / mm. The higher the tensile modulus, the higher the sheet strength. Table 1 shows the results.

(Evaluation of particulate collection performance)
In this evaluation, seven types of test powder (particles) specified in JIS Z 8901 were used as a model of fine particle contamination on a flooring floor (DAG floor, manufactured by Kitae Corporation) having a length (wiping direction) of 90 cm × width 90 cm. 0.1 g of a test powder (particle diameter: 5 to 75 μm) or 11 kinds of test powders (particle diameter: 1 to 8 μm) was sprayed in a range of 15 cm to 30 cm from the front of the wiping direction in an area of 15 cm length × 90 cm width. With respect to this flooring, the wiping sheet of the example or the comparative example was wiped by reciprocating twice in the wiping direction every 30 cm in width. This operation was performed for six sets. Regarding the direction of the sheet during wiping, the width direction Y in FIG. 4 was the same as the wiping direction. The change in the sheet mass before and after wiping was measured, and the performance of collecting fine particles was evaluated based on the following criteria. Table 1 shows the results.

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

(Evaluation of hair collection performance)
In this evaluation, a flooring floor (DAG floor, manufactured by Kitae Corporation) on which 20 hairs of 10 cm were sprayed per tatami (1820 mm × 910 mm) was wiped for 6 tatami mats. Regarding the direction of the sheet during wiping, the width direction Y in FIG. 4 was the same as the wiping direction. The number of hairs collected on the wiping sheet after wiping was measured, and the hair collecting performance was evaluated based on the following criteria. Table 1 shows the results.

<Calculation formula>
Hair collection rate (%) = 100 × (number of hairs collected on wiping sheet [books]) / (number of hairs sprayed [books])
<Capture performance>
A: Hair collection rate is 80% or more, and hair collection performance is very high.
：: Hair collection rate is 60% or more and less than 80%, and hair collection performance is high.
Δ: Hair collection rate is 40% or more and less than 60%, and the hair collection performance is slightly low.
×: 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 was applied to the wet wiping sheets of Examples and Comparative Examples, and a wiping speed of 1 m / s was applied to a flooring floor (Conbit New Advance 101, manufactured by Wood One Co., Ltd.) as a wiping target surface. Wiping was performed continuously for ³ minutes (corresponding to 32.4 m ² ). From the liquid release amount (g) for each tatami mat, the amount of release at each wiping area was measured with respect to the initial impregnation amount of the cleaning liquid, and the sustained release of the cleaning liquid was evaluated based on the following criteria. Table 1 shows the results. The higher the washing liquid release rate, the better the sustained release property.

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

As shown in Table 1, the wiping sheet of the present invention has a high sheet strength, a fine particle stain, and a fiber stain such as hair by containing a modified fiber and a fiber having a smaller diameter than the fiber as constituent fibers. It can be seen that it has a high trapping performance. Further, it can be seen that the wiping sheet of the present invention has a high sustained release property of the cleaning liquid when used in a wet mode, and enables wiping in a wide range.

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

Claims

A fiber aggregate including at least a first fiber and a second fiber having a smaller diameter than the fiber is provided. The fiber aggregate is formed by entanglement of the fibers, and is located on a first surface and on a side opposite to the first surface. A wiping sheet having a second surface,
The proportion of the second fibers present is higher on the first surface than on the second surface,
A wiping sheet, wherein at least the first fiber is a modified fiber whose cross section is non-circular.
The wiping sheet according to claim 1, wherein both the first fibers and the second fibers are the irregular fibers.
The wiping sheet according to claim 1 or 2, wherein the modified fiber has a cross-sectional shape of a convex polygon or a regular polygon.
The wiping sheet according to any one of claims 1 to 3, wherein the modified fiber has a multi-lobed cross-sectional shape.
ワイ The wiping sheet according to any one of claims 1 to 4, wherein the wiping sheet 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 another member in addition to the fiber assembly.
The wiping sheet according to any one of claims 1 to 6, wherein the presence ratio of the second fibers on the first surface is represented by an area ratio and is 40% or more and 100% or less.
The wiping sheet according to any one of claims 1 to 7, wherein the presence ratio of the second fibers on the second surface is 1% or more and 60% or less as an area ratio.
The wiping sheet according to any one of claims 1 to 8, wherein the presence ratio of the first fibers on the first surface is 0% or more and 60% or less as an area ratio.
The wiping sheet according to any one of claims 1 to 9, wherein the proportion of the first fibers on the second surface occupied by the first fibers 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 assembly are not fused to each other.
The wiping sheet according to any one of claims 1 to 11, wherein a cleaning liquid is carried 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 a surfactant, a bactericide, a fragrance, a fragrance, a deodorant, a pH adjuster, an alcohol, abrasive particles, a gloss imparting agent, and a thickener. Item 14. A wiping sheet according to item 13.
The wiping sheet according to any one of claims 1 to 14, wherein the first fibers are fibers 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 a ratio of the fineness of the first fiber to the fineness of the second fiber is 15 or more and 1500 or less.
20. 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.
On one surface of the wiping sheet are formed a pattern concave portion and a pattern convex portion that constitute the concave and convex portion of the macroscopic pattern, and the boundary between the pattern concave portion and the pattern convex portion is macroscopically viewed. The wiping sheet according to any one of claims 1 to 21, wherein the wiping sheet has a curved portion.
23. The wiping sheet according to claim 22, wherein when the uneven portion is formed on one surface, the other surface is flat.