JP7511316B2 - Wiping Sheet - Google Patents

Description

The present invention relates to a wiping sheet.

Fibers made from thermoplastic resins are used in various applications in the form of nonwoven fabrics in which the fibers are entangled. For example, Patent Document 1 discloses a nonwoven fabric for wipers in which a wet-laid nonwoven fabric containing non-split type modified cross-section crimped fibers of 0.6 to 3.3 dtex and fibrillated fibers is subjected to a hydroentanglement process. The document states that this nonwoven fabric has excellent wiping properties, liquid absorption properties, bulkiness, and strength, and can therefore be used for applications such as dust wipers.

Patent document 2 discloses a nonwoven fabric made of 20-80% by mass of multi-lobular flat cross-section polyester fibers and 20-80% by mass of cellulosic fibers. The document states that this nonwoven fabric has high liquid absorption and release capabilities for water, chemicals, and other liquids, and also has appropriate bulk and flexibility, making it suitable for use in personal cleaning and cosmetic applications.

JP 2010-81987 A International Publication No. 2014/132690

In general, nonwoven fabrics used in wiping sheets for wiping hard surfaces such as flooring, walls, and furniture must have both dirt collection capabilities and strength. Dirt collection capabilities and strength can be adjusted by the degree of freedom of the fibers that make up the nonwoven fabric, i.e., the ease of movement of the fibers, but these effects are not compatible. For example, when a nonwoven fabric with a high degree of freedom of fibers is used, the ability to collect dirt such as hair and fine particles is improved, but the strength of the wiping sheet itself is reduced, and it may not be able to withstand practical use. On the other hand, when a nonwoven fabric with a low degree of freedom of fibers is used, the strength of the wiping sheet itself is increased, but the dirt collection capabilities are reduced.

The nonwoven fabrics in Patent Documents 1 and 2 are manufactured by combining two types of fibers to ensure the above-mentioned wiping properties, bulkiness, strength, etc., but this is not appropriate from the standpoint of raw material supply and manufacturing costs. In addition, the nonwoven fabrics described in these documents are said to be suitable for increasing the strength of the nonwoven fabric by fusing the fibers together using heat-fusible fibers, but the degree of freedom of the constituent fibers of the nonwoven fabric is reduced due to the fusing of the fibers together, and as a result, the dirt collection ability cannot be sufficiently improved.

Therefore, the objective of the present invention is to provide a wiping sheet that can solve the shortcomings of the conventional technology.

As a result of intensive research by the present inventors to solve the above problems, it was unexpectedly discovered that by using irregular fibers having a non-circular cross-sectional shape as the constituent fibers of the wiping sheet, it is possible to increase the strength of the sheet while maintaining fiber freedom that is advantageous for collecting dirt.
The present invention has been made based on the above findings, and provides a wiping sheet having a nonwoven fabric including irregularly shaped fibers having a noncircular cross-sectional shape, the fibers being entangled without being fused to each other,
The nonwoven fabric has a tensile strength of 80 N/30 mm or more and 200 N/30 mm or less,
The above-mentioned problems are solved by providing a wiping sheet in which the amount of fiber shedding, which indicates the degree of freedom of the fibers, is 2 mg or more and 50 mg or less.

The present invention provides a wiping sheet that combines strength during use with improved freedom in the fibers that make up the sheet, providing both sheet strength and dirt collection capabilities.

1(a) to (e) are perspective schematic diagrams of the cross-sectional shapes of non-circular fibers used in the wiping sheet of the present invention. 2(a) to (c) are enlarged plan views of the cross-sectional shapes of the non-circular fibers in FIG. 1(b), (d) and (e). FIG. 3 is a schematic diagram of a manufacturing apparatus used for manufacturing the wiping sheet of the present invention. FIG. 4 is a graph showing the tensile strength of the nonwoven fabric in the wiping sheets of the Examples and Comparative Examples.

The wiping sheet of the present invention will be described below based on its preferred embodiment. In the present invention, wiping includes both cleaning and wiping, and includes, for example, cleaning of floors, walls, ceilings, pillars, and other parts of buildings, cleaning of fixtures and fixtures, wiping off objects, wiping the body and tools related to the body, etc.

The wiping sheet of the present invention includes a nonwoven fabric that contains irregular fibers, and preferably is mainly composed of irregular fibers. The irregular fibers are stacked, entangled, or bonded to each other to form the nonwoven fabric. From the viewpoint of increasing the degree of freedom of the fibers and increasing the dirt collection efficiency, it is preferable that the fibers that make up the nonwoven fabric are not fused to each other. "Mainly composed of" means that the nonwoven fabric that makes up the wiping sheet contains 50% by mass or more of irregular fibers.

The wiping sheet of the present invention may be composed of a single layer of nonwoven fabric containing irregular fibers, or may be composed of a multi-layered nonwoven fabric having a layer containing irregular fibers and a layer not containing irregular fibers. The wiping sheet of the present invention may also be composed of a multi-layered nonwoven fabric having a layer containing a first irregular fiber and a layer containing a second irregular fiber different from the first irregular fiber.

The wiping sheet of the present invention may be composed solely of a nonwoven fabric (whether single-layer or multi-layer) containing irregular fibers, or may have a multi-ply structure in which a nonwoven fabric containing irregular fibers is layered with a nonwoven fabric not containing irregular fibers or with another sheet material other than a nonwoven fabric.

When the wiping sheet of the present invention is made of a single-layer nonwoven fabric, the proportion of the irregular fibers in the wiping sheet of the present invention is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, from the viewpoint of achieving a better balance between sheet strength and dirt collection properties. Fibers that can be contained in the wiping sheet of the present invention other than the irregular fibers are fibers with a perfectly circular cross section. When the wiping sheet is made of a single-layer nonwoven fabric, such fibers are preferably contained in a proportion of at most 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

The irregular fiber contained in the wiping sheet of the present invention refers to a fiber whose cross-sectional shape is non-circular. The cross-sectional shape of the fiber is non-circular means that the cross-sectional shape of the fiber is other than a perfect circle. Examples of irregular fibers 2 having such a cross-sectional shape of the fiber include those having a cross-sectional shape such as a triangle shown in FIG. 1(a), a convex polygon or regular polygon such as a square, a pentagon, or a hexagon, a star-shaped polygon shown in FIG. 1(b), an ellipse shown in FIG. 1(c), a W-shape shown in FIG. 1(d), and a multi-leaf shape shown in FIG. 1(e), but are not particularly limited as long as the effect of the present invention is achieved. It is preferable that the irregular fiber has at least one convex portion having a sharp apex in its cross-sectional shape, more preferably two or more, and even more preferably three or more. The sharp apex refers to a convex outline in the cross-sectional shape of the irregular fiber, for example, (a) defined by the intersection of two non-parallel straight lines, (b) defined by the intersection of one straight line and one curved line, or (c) defined by the intersection of two curved lines. For example, the irregular fiber shown in FIG. 1(a) has three sharp apexes, the irregular fiber shown in FIG. 1(b) has six sharp apexes, and the irregular fiber shown in FIG. 1(e) has eight sharp apexes. In the present invention, one type of irregular fiber may be used alone, or two or more types of irregular fibers having different cross-sectional shapes may be used in combination.

From the viewpoint of improving production efficiency, it is preferable that the irregular fibers are made from a fiber-forming resin as a raw material. Examples of such resins include various thermoplastic resins. Examples of thermoplastic resins include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyamide resins, vinyl resins such as polyvinyl chloride and polystyrene, acrylic resins such as polyacrylic acid and polymethyl methacrylate, and fluororesins such as polyperfluoroethylene. One of these can be used alone or two or more can be used in combination.

From the viewpoint of ease of use during wiping and dirt collection efficiency, the fineness of the irregular fibers contained in the wiping sheet is preferably 0.8 dtex or more, more preferably 1 dtex or more, and even more preferably 1.2 dtex or more, and the upper limit is preferably 4 dtex or less, more preferably 3.5 dtex or less, and even more preferably 3 dtex or less.

When the wiping sheet contains fibers with a perfectly circular cross section, the fineness of the fibers is preferably 0.6 dtex or more, more preferably 1.0 dtex or more, and even more preferably 1.2 dtex or more, from the viewpoint of ease of use during wiping and dirt collection efficiency. It is also preferably 4.0 dtex or less, more preferably 3.5 dtex or less, and even more preferably 3.0 dtex or less.

From the viewpoint of maintaining the strength of the wiping sheet during wiping, the tensile strength of the nonwoven fabric constituting the wiping sheet is preferably 80 N/30 mm or more, more preferably 85 N/30 mm or more, and even more preferably 90 N/30 mm or more, and the upper limit is preferably 200 N/30 mm or less, more preferably 150 N/30 mm or less, and even more preferably 120 N/30 mm or less. Specifically, the tensile strength of the nonwoven fabric constituting the wiping sheet is preferably 80 N/30 mm or more and 200 N/30 mm or less, more preferably 85 N/30 mm or more and 150 N/30 mm or less, and even more preferably 90 N/30 mm or more and 120 N/30 mm or less. This tensile strength may be satisfied in either the machine direction (MD) or the cross direction (CD) of the nonwoven fabric, and it is more preferable that it is satisfied in both. The method for measuring the tensile strength of the nonwoven fabric will be described in detail in the examples described later.

From the viewpoint of increasing the degree of freedom of the fibers of the wiping sheet and increasing the ability to collect dirt such as hair, the amount of fiber shedding from the nonwoven fabric constituting the wiping sheet is preferably 2 mg or more, more preferably 3 mg or more, and even more preferably 5 mg or more, and the upper limit is preferably 50 mg or less, more preferably 25 mg or less, and even more preferably 10 mg or less. Specifically, the amount of fiber shedding is preferably 2 mg or more and 50 mg or less, more preferably 3 mg or more and 25 mg or less, and even more preferably 5 mg or more and 10 mg or less. The method for measuring the amount of fiber shedding will be described in detail in the examples described later.

In this specification, the "amount of fiber shedding" is a value indicating the degree of freedom of the fibers in the wiping sheet. In other words, the amount of fiber shedding quantitatively indicates the ease of movement of the fibers against external forces, and the greater the amount of fiber shedding, the higher the degree of freedom of the fibers. If the amount of fiber shedding is less than the lower limit of the above range, the friction and bonding between the fibers is strong, so the strength of the wiping sheet itself is high, but the degree of freedom of the fibers is reduced, and the dirt collection ability is reduced. On the other hand, if the amount of fiber shedding exceeds the upper limit of the above range, the friction and bonding between the fibers is weak, so the degree of freedom of the fibers is high and the dirt collection ability is high, but the strength of the wiping sheet itself is reduced. The amount of fiber shedding in such a range can be appropriately adjusted, for example, by appropriately selecting the type of irregular fiber or changing the conditions of water flow entanglement in the manufacturing method of the wiping sheet described later.

When the length of the longest line segment among the line segments that cross the cross section of the irregular fiber is A, and the length of the longest line segment among the line segments that are perpendicular to the line segment and cross the cross section is B (see Figures 2(a) to (c)), the value of A/B is preferably 1.2 or more, more preferably 1.5 or more, and even 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 and 5 or less, more preferably 1.5 or more and 4 or less, and even more preferably 2 or more and 3 or less. With this configuration, the fibers that make up the wiping sheet are easily entangled with dirt such as hair, and these dirt can be hooked on the fibers and removed from the surface to be wiped.

Regarding the above-mentioned length A and length B, examples of cross-sectional shapes other than those shown in Figures 2(a) to (c) include irregular fibers whose cross-sectional shape is an equilateral triangle, where length A is the length of one side of the equilateral triangle, and length B is the length of a perpendicular line drawn from a vertex to one side. Also, in irregular fibers whose cross-sectional shape is an ellipse, length A is the major axis of the ellipse, and length B is the minor axis of the ellipse.

When the wiping sheet contains two or more types of irregular fibers with different cross-sectional shapes, the above A and B refer to the average values of A and B measured for all types of irregular fibers.

From the viewpoint of achieving both operability during wiping and dirt collection, the length A is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, provided that the above-mentioned range of A/B is satisfied, and the upper limit is preferably 80 μm or less, preferably 50 μm or less, and preferably 25 μm or less.

From a similar perspective, length B is preferably 0.2 μm or more, more preferably 1 μm or more, and even more preferably 2 μm or more, provided that the above-mentioned A/B range is satisfied, and the upper limit is preferably 40 μm or less, preferably 20 μm or less, and preferably 15 μm or less.

As shown in Figures 2(a) to (c), when the contour line in the cross section of the irregular fiber is viewed in the circumferential direction, if the shape has multiple protrusions P and recesses R located between adjacent protrusions P, then when the length of the line segment connecting the vertices of adjacent protrusions P is C and the length of the perpendicular line dropped from the line segment to the bottom position of the recess R is D (see Figures 2(a) to (c)), the value of C/D is preferably 0.1 or more, more preferably 1 or more, and even 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. With this configuration, the surface area of the fiber alone increases, increasing the contact area with dirt, thereby further improving the dirt collection ability.

When observing the cross section of the irregular fiber, if the lengths C of the line segments connecting the vertices of arbitrarily selected adjacent convex portions P are different, the value of C for calculating the value of C/D is the average value of all the values of C. Similarly, if the lengths D of the perpendicular lines at arbitrarily selected concave portions R are different, the value of D for calculating the value of C/D is the average value of all the values of D. In the following description, when the values of C and D are mentioned, the values in question are the average values of C and D.

From the viewpoint of improving operability and dirt collection efficiency during wiping, the length C is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more, provided that the above-mentioned C/D range is satisfied, and the upper limit is preferably 20 μm or less, preferably 10 μm or less, and preferably 5 μm or less.

From a similar perspective, the length D is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more, provided that the above-mentioned C/D range is satisfied, and the upper limit 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 measurement method. That is, the produced nonwoven fabric was cut using a razor or the like while maintaining the cross-sectional shape of the fibers, and then 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 nonwoven fabric was observed at a magnification of 500 to 1000 times, and the above-mentioned lengths A to D on the fiber cross section were each measured using the length measurement tool of the attached software.

From the viewpoint of exhibiting the rigidity and strength of the wiping sheet, the basis weight of the nonwoven fabric constituting the wiping sheet is preferably 40 g/m ² or more, more preferably 45 g/m ² or more, and even more preferably 50 g/m ² or more, and the upper limit is preferably 140 g/m ² or less, more preferably 100 g/m ² or less, and even more preferably 80 g/m ² or less. Specifically, the basis weight of the nonwoven fabric 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 even more preferably 50 g/m ² or more and 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/ ^m2 , and more preferably 1.0 mm or more, and the upper limit is preferably 2.5 mm or less under the same load, and more preferably 3 mm or less.

When wiping, the wiping sheet may be used as is (a so-called dry mode), or may be used in a mode in which the nonwoven fabric is coated, sprayed, supported or impregnated with a cleaning liquid (a so-called wet mode). 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 of the surface to be wiped, it is preferable that the nonwoven fabric constituting the wiping sheet supports a cleaning liquid. Since the nonwoven fabric contains irregular fibers, the gaps between the fibers can be made large, which has the advantage of improving the liquid retention of the cleaning liquid in the wiping sheet.

When the wiping sheet is used in a wet mode during wiping, the cleaning liquid carried by the sheet can be water alone or an aqueous solution containing additives, which has a general composition used in wet wiping sheets. Additives used in cleaning liquids include surfactants, disinfectants, fragrances, air fresheners, deodorants, pH adjusters, alcohol, and abrasive particles.

The fiber length of the irregular fibers depends on the manufacturing method of the fibers, but is generally 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 above has been an explanation of one embodiment of the wiping sheet of the present invention. Below, a preferred manufacturing method for the wiping sheet will be explained with reference to FIG. 3. FIG. 3 shows a manufacturing apparatus 10 that is suitable for use in manufacturing the wiping sheet. The manufacturing apparatus 10 includes a web forming section 20 and a hydroentanglement section 30, in this order, along the conveying direction (MD direction). The configuration of the manufacturing apparatus 10 shown below is the same as that of a general manufacturing apparatus for nonwoven fabrics using the spunlace method.

The web forming section 20 forms a web of irregularly shaped fibers 2. The web forming section 20 is equipped with a carding machine 21 that forms a web from the irregularly shaped fibers 2, which are the raw material of the wiping sheet. The web of irregularly shaped fibers 2 formed by the carding machine 21 is transported to the hydroentanglement section 30.

The water flow entanglement unit 30 entangles the web of irregular fibers 2 with a water flow to form a nonwoven fabric 1A containing irregular fibers 2. The water flow entanglement unit 30 includes a water flow nozzle 31 that sprays a water flow onto the web of irregular fibers 2, and a support belt 32 that is an endless belt. The water flow nozzle 31 is located above the web of irregular fibers 2 and the support belt 32, and is capable of spraying a high-pressure water flow over the entire width direction (CD direction) of the web of irregular fibers 2. The support belt 32 is arranged opposite the water flow nozzle 31, and has a structure with holes in various patterns such as a lattice pattern to allow the sprayed water to pass through (not shown). The nonwoven fabric 1A containing irregular fibers 2 entangled by the water flow sprayed from the water flow nozzle 31 is transported to a downstream process by the support belt 32.

In particular, a nonwoven fabric having the above-mentioned tensile strength and fiber shedding amount can be produced by adjusting the conditions of hydroentanglement. Specifically, the water pressure sprayed from the water flow nozzle 31 onto the web of irregular fibers 2 is preferably 30 kg/ ^cm2 or more and 80 kg/ ^cm2 or less, more preferably 40 kg/ ^cm2 or more and 60 kg/ ^cm2 or less, and the conveying speed in the MD direction of the web of irregular fibers 2 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.

Through these steps, a nonwoven fabric 1A can be formed in which the irregular fibers 2 are entangled without being fused to each other. After forming the nonwoven fabric 1A, the nonwoven fabric 1A may be dried, if necessary, using a heater or the like (not shown).

Finally, the manufactured nonwoven fabric 1A can be used as a dry wiping sheet 1 as is, or can be made into a wet wiping sheet 1 by further applying a cleaning liquid to the nonwoven fabric 1A.

The wiping sheet produced in this manner can be used alone or attached to a cleaning tool such as a wiper to clean floors, walls, and other surfaces in buildings, fittings such as cupboards, window panes, mirrors, doors, and doorknobs, rugs, carpets, furniture such as dining tables, kitchens, toilets, and body cleaning, as well as for hygiene products and packaging.

Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above embodiments. For example, as described above, the wiping sheet of the present invention may be composed only of a nonwoven fabric containing irregular fibers, or may have other layers in addition to the nonwoven fabric. When the wiping sheet is composed of a nonwoven fabric and other layers laminated together, the surface of the nonwoven fabric containing irregular fibers facing outward serves as the wiping surface.

The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited to these examples.

Example 1
As shown in FIG. 1(a), a nonwoven fabric was produced by hydroentangling using irregular fibers whose cross-sectional shape was triangular. The hydroentangling conditions were a water pressure of 50 kg/ ^cm2 sprayed from the water nozzle 31 and a conveying speed of the irregular fiber web of 5 m/min. The dimensions of the nonwoven fabric were 285 mm x 205 mm, and the nonwoven fabric was left as it was (i.e., in a dry state) to produce the desired wiping sheet. Polypropylene (PP) was used as the raw material resin for the irregular fibers. The fineness of the irregular fibers was 1.45 dtex. The basis weight of the nonwoven fabric was 60 g/ ^m2 .

Example 2
As shown in Fig. 1(b), a wiping sheet was obtained in the same manner as in Example 1, except that a nonwoven fabric was produced using irregular fibers having a star-shaped hexagonal cross section. The fineness of the irregular fibers was 1.3 dtex. The basis weight of the nonwoven fabric was 60 g/ ^m2 .

Example 3
As shown in Fig. 1(c), a wiping sheet was obtained in the same manner as in Example 1, except that a nonwoven fabric was produced using irregular fibers having an elliptical cross-sectional shape. The fineness of the irregular fibers was 2.2 dtex. The basis weight of the nonwoven fabric was 60 g/ ^m2 .

Example 4
As shown in Fig. 1(d), a wiping sheet was obtained in the same manner as in Example 1, except that a nonwoven fabric was produced using irregular fibers having a W-shaped cross section. The fineness of the irregular fibers was 2.85 dtex. The basis weight of the nonwoven fabric was 60 g/ ^m2 .

Example 5
As shown in Fig. 1(e), a wiping sheet was obtained in the same manner as in Example 1, except that a nonwoven fabric was produced using irregular fibers having a multi-lobal cross-sectional shape. The fineness of the irregular fibers was 1.7 dtex. The basis weight of the nonwoven fabric was 60 g/ ^m2 .

Comparative Example 1
A wiping sheet was obtained in the same manner as in Example 1, except that the nonwoven fabric was produced using fibers having a circular cross-sectional shape. The fineness of the fibers was 1.45 dtex. The basis weight of the nonwoven fabric was 60 g/ ^m2 .

Comparative Example 2
A wiping sheet was obtained in the same manner as in Example 5, except that the conditions for the hydroentanglement were a water pressure of 50 kg/ ^cm2 sprayed from the water nozzle 31 and a conveying speed of the irregular fiber web of 1 m/min.

Comparative Example 3
A dry wiping sheet was obtained using a nonwoven fabric produced by a wet spunlace method using pulp and polyester fibers as the raw materials for the fibers. The fiber fineness was 2.5 dtex. The basis weight of the nonwoven fabric was 75 g/ ^m2 .

Comparative Example 4
A wiping sheet was obtained in the same manner as in Comparative Example 1, except that the nonwoven fabric was produced at a fiber web conveying speed of 1 m/min. The fiber fineness was 1.45 dtex. The basis weight of the nonwoven fabric was 60 g/ ^m2 .

[Measurement of tensile strength]
The tensile strength of the wiping sheets of the examples and comparative examples was measured. In detail, a tensile strength tester (AG-IS 100N, manufactured by Shimadzu Corporation) was used to measure the maximum load (N) until the sample broke when a sample with a length of 150 mm and a width of 30 mm was pulled at a span of 100 mm and a speed of 300 mm/min. The tensile strength (N/30 mm) in the conveying direction (MD direction) and the width direction (CD direction) perpendicular to the MD direction was measured six times, and the average value and standard deviation of the measured values of the tensile strength were calculated. The results are shown in FIG. 4 and Table 1.

[Measurement of fiber shedding amount]
The amount of fiber shedding was measured for the nonwoven fabrics of the examples and comparative examples. In detail, the nonwoven fabric to be evaluated was placed in contact with a circular urethane foam rotating at a rotation speed of 2.3 m/s under a load of 5.5 N/ ^m2 , and friction was applied for 1.5 minutes. After that, the fibers attached to the urethane foam were collected with an adhesive tape, and the mass (mg) of the fibers was measured. The greater the amount of fiber shedding, the higher the degree of freedom of the fibers. The results are shown in Table 1.

[Evaluation of hair collection ability]
The wiping sheets of the examples and comparative examples were evaluated for hair collection ability. In detail, a flooring (Combit New Advance 101, manufactured by Wood One Co., Ltd.) with 10 hairs scattered thereon was used as the wiping target surface, and a pressure of 0.16 kN/ ^m2 was applied to wipe an area of 0.27 ^m2 , and the hair collection ability at that time was evaluated according to the following criteria. The results are shown in Table 1.
A: 70% or more of the hair was captured, and the capture performance was very good.
B: 50% or more and less than 70% of the hair was captured, and the capture performance was good.
C: 0% or more and less than 50% of the hair was collected, and the collection performance was poor.

As shown in FIG. 4 and Table 1, the wiping sheets of Examples 1 to 5 using irregular fibers have higher tensile strength in the MD and CD directions compared to the wiping sheet of Comparative Example 1 not using irregular fibers. Also, as shown in Table 1, the wiping sheets of Examples 1 to 5 have a greater amount of fiber shedding compared to the wiping sheets of Comparative Examples 2 and 3, meaning that the fibers have a higher degree of freedom and higher hair collection ability. In particular, when comparing Example 5 and Comparative Example 2 using the same fibers, it is found that a sheet that can achieve both tensile strength and hair collection ability can be manufactured by weakening the conditions for hydroentanglement.

From the above, it can be seen that the wiping sheet of the present invention achieves both strength during use of the sheet and improved freedom of the constituent fibers of the sheet, is durable for practical use during wiping, and has improved ability to collect dirt such as hair.

Reference Signs List 1 Wiping sheet 1A Nonwoven fabric 2 Deformed fiber 10 Manufacturing device 20 Web forming section 30 Water flow entanglement section MD Transport direction

Claims (2)

A wiping sheet comprising a single layer of spunlace nonwoven fabric containing irregular fibers having a non-circular cross-sectional shape,
The non-circular fiber has a cross-sectional shape that is a star-shaped hexagon, a W-shape, or a multi-lobe shape, and has a shape having a plurality of convex portions and concave portions located between adjacent convex portions when the contour line of the cross-sectional shape is viewed in the circumferential direction,
Among the line segments that cross the cross section of the irregular fiber, the length of the longest line segment is defined as A, and among the line segments that are perpendicular to the line segment and cross the cross section, the length of the longest line segment is defined as B. The value of A/B is 1.2 or more and 3.0 or less,
a length of a line segment connecting vertices of adjacent convex portions is C, and a length of a perpendicular line drawn from the line segment to the bottom position of each convex portion is D, the value of C/D is 2.0 or more and 4.0 or less,
The nonwoven fabric is formed by hydroentanglement of fibers constituting the nonwoven fabric without fusion with each other,
The nonwoven fabric contains 100 % by mass of the irregular fibers ,
The tensile strength of the wiping sheet is 90 N/30 mm or more and 120 N/30 mm or less,
A wiping sheet having a fiber shedding amount, which indicates the degree of freedom of the fibers, of 5 mg or more and 10 mg or less. The wiping sheet according to claim 1 , wherein the nonwoven fabric has a basis weight of 40 g/m ² or more and 140 g/m ² or less.

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