JP7060411B2 - Wiping sheet - Google Patents

Description

The present invention relates to a wiping sheet.

Various proposals have been made so far for wiping sheets that wipe off dirt from various articles. For example, Patent Document 1 describes a cleaning sheet including a wiping portion made of a liquid-permeable surface sheet and a liquid absorber that absorbs the liquid wiped by the wiping portion. The cleaning sheet has a large number of convex portions that come into contact with the surface to be cleaned from the viewpoint of removing stains and the like on the floor and suppressing foaming when wiping the wax agent or the like on the floor to improve the finish. Have on the surface sheet.

Japanese Unexamined Patent Publication No. 9-131288

The stains wiped off by the wiping sheet include oil stains such as sebum and cooking oil. However, with the conventional wiping sheet, it may be spread over the surface to be wiped while absorbing oil stains, and it is difficult to completely wipe it off.

Therefore, the present invention relates to a wiping sheet that has a high wiping property of oil stains and can suppress the spread of oil stains on a wiping object due to wiping.

The present invention is a wiping sheet in which a plurality of fiber layers are laminated, and the fiber layer constituting the wiping surface of the wiping sheet has a larger interfiber distance than other fiber layers, and the plurality of fibers Each layer has an embossed recess, and the embossed recess of the fiber layer constituting the wiping surface is arranged toward the wiping surface to provide a wiping sheet.

The wiping sheet of the present invention has a high wiping property of oil stains, and can suppress the spread of oil stains on the wiped object due to wiping.

It is a partially enlarged sectional view schematically showing a preferable form of the wiping sheet of this invention. (A) is an explanatory view schematically showing the flow of oil stains in the cross-sectional view of FIG. 1, and (B) is a modified example thereof. It is a partially enlarged sectional view schematically showing another preferable form of the wiping sheet of this invention. It is a partially enlarged sectional view schematically showing still another preferable form of the wiping sheet of this invention.

Hereinafter, the wiping sheet of the present invention will be described with reference to the drawings based on the preferred embodiment thereof.

In the present invention, unless otherwise specified, the surface of the wiping sheet that comes into contact with oil stains on the surface to be cleaned is referred to as a wiping surface or a lower surface, and the surface opposite to this is referred to as an upper surface. For each of the fiber layers in which the wiping sheets are laminated, the surfaces relatively close to the wiping surface (lower surface) and the upper surface are referred to as the wiping surface (lower surface) side surface and the upper surface side surface, respectively. The normal direction of the wiping surface (lower surface) or upper surface of the wiping sheet is called the thickness direction.
Further, the term "wiping" as used herein means to come into contact with an object to be cleaned and wipe off the dirt, and the dirt to be wiped off includes various kinds of dirt, and particularly oil stains are targeted. The object to be cleaned in the wiping sheet of the present invention is not particularly limited, and examples thereof include various items to which dirt is attached.
Further, the wiping sheet of the present invention may be either dry type or wet type, and may or may not contain a component that assists in wiping off dirt other than the constituent fibers. .. If it is not included, a component that helps wipe off dirt may be used separately at the time of wiping.

FIG. 1 shows a cross section of the wiping sheet 10 of the present embodiment in the sheet thickness direction. The wiping sheet 10 is formed by laminating a plurality of fiber layers. Specifically, two fiber layers 1 and 2 are laminated to form a sheet. The fiber layer 2 constitutes the wiping surface 10A of the wiping sheet 10, and the fiber layer 1 is laminated on the upper surface side opposite to the wiping surface of the fiber layer 2 (hereinafter, the fiber layer 1 and the fiber layer 2 are laminated. They are referred to as the first fiber layer 1 and the second fiber layer 2, respectively). That is, in the present embodiment, the wiping sheet 10 is composed of two layers, the second fiber layer 2 constitutes the wiping surface 10A, and the first fiber layer 1 constitutes the upper surface 10B. However, the number of fiber layers to be laminated is not limited to the two layers in the present embodiment, and may be three or more layers. Here, the fiber layers to be laminated can be classified according to the average fiber distance, the average fiber diameter, the fiber material, and the like.

In the wiping sheet 10, the second fiber layer 2 constituting the wiping surface 10A has a larger average interfiber distance than the first fiber layer 1 on the upper surface 10B side. That is, the second fiber layer 2 on the wiping surface side has a wider space for oil absorption between the fibers than the first fiber layer 1 on the upper surface 10B side, and the capillary force difference between the two layers is generated. ing. As long as the difference in capillary force is generated and oil stains can be effectively transferred from the second fiber layer 2 to the first fiber layer 1, the first fiber layer 1 and the second fiber layer 2 may be directly laminated. Often, a further fiber layer may be interposed between the two layers. In the latter case, for example, a further fiber layer is interposed between the second fiber layer 2 on the wiping surface 10A side and the first fiber layer 1 on the upper surface 10B side, so that the wiping sheet 10 is provided with a fiber layer having different hydrophobicity. It is mentioned that it has a laminated structure in which is alternately arranged. As long as the wiping sheet 10 has such a laminated structure, the additional fiber layer to intervene may be a single layer or may be two or more layers. However, from the viewpoint of minimizing the residual oil stains on the second fiber layer 2 on the wiping surface side and quickly transferring as much oil stains as possible to the first fiber layer 1 on the upper surface side, the first fiber layer 1 and the second fiber. It is preferable that the layer 2 is directly laminated.

In addition, the wiping sheet 10 has embossed recesses in both the first fiber layer 1 and the second fiber layer 2 (hereinafter referred to as embossed recesses 31 of the first fiber layer 1 and embossed recesses 32 of the second fiber layer 2). ). As a result, the fiber-consolidated portions around the embossed recesses 31 and 32 of each layer are arranged in the thickness direction, and a path for the transfer of the wiped oil from the second fiber layer 2 to the first fiber layer 1 is created. In addition, it also serves as a route for transmitting the liquid drawing property due to the difference in capillary force between the two layers due to the difference in the average fiber distance described above to the wiping surface side.
In addition, the embossed recess 32 of the second fiber layer 2 constituting the wiping surface 10A is arranged toward the wiping surface 10A. As a result, the oil stain is enclosed in the space of the embossed recess, and the capillary force is directly applied to the oil stain of the object to be cleaned, so that the average interfiber distance is wider than that of the first fiber layer 1. I try to get into the space.

The wiping sheet 10 quickly takes in oil stains on the object to be cleaned (improved oil absorption and wiping property) due to the difference in the average distance between fibers and the configuration of the embossed recesses, and has liquid (oil) transferability between the fiber layers. improves. Therefore, it is possible to suppress the spread of oil stains in the contact range of the wiping sheet 10 with the surface to be cleaned. Hereinafter, this point will be described in more detail.

The above average interfiber distance can be obtained by the following formula [I].

Here, π is the pi.
That is, the average interfiber distance can be calculated by measuring the basis weight, fiber diameter, sheet thickness, and specific gravity in each layer constituting the wiping sheet.

Generally, it is known that the capillary pressure follows the following formula [II].

The Pc derived from the above formula is a value using the summary statistic derived from the measurement of the non-woven fabric. Here, Pc is the capillary pressure of the fiber (N / m ² ), γ _L is the surface tension of the liquid (N / m), θ is the contact angle (rad) between the fiber and the liquid, and r is. The radius of the capillary (m). Since the capillary radius corresponds to the interfiber distance, the average capillary pressure of the fibers can be obtained by using the value of the average interfiber distance for r.

In order to measure Pc, it is necessary to measure the surface tension of the liquid, the fiber diameter, and the contact angle between the fiber and the liquid. The surface tension is an automatic surface tension meter based on the plate method such as DY-200 manufactured by Kyowa Interface Science Co., Ltd. at 20 ° C. and 65% R.M. H. The average value measured 10 times in the environment of. The fiber diameter is measured from observation with a scanning electron microscope at an observation magnification of 350 times and 30 fibers per observation, and these are randomly measured at 5 locations and the average value of 150 fiber diameters measured. For the contact angle between the fiber and the liquid, the constituent fibers of the nonwoven fabric are identified by Fourier transform infrared spectroscopy (FTIR), and the contact angle on a resin plate having the same composition is measured. Specifically, the contact angle when 3 seconds have passed after dropping 1 μL with a fully automatic contact angle meter such as DMo-901 manufactured by Kyowa Interface Science Co., Ltd. is measured at 5 points on the plate and used as the average value. .. If there are multiple fiber materials, the contact angle is measured in the same way for each material, and the value at the time of Pc calculation is the weighted average of the contact angles based on the surface area ratio of each fiber component. Let it be θ in.

As is clear from the above equation, the smaller the capillary radius (average interfiber distance), the higher the capillary pressure. In the present embodiment, the capillary pressure of the first fiber layer 1 is increased by reducing the average interfiber distance. When the oil stain is wiped off by using the wiping sheet 10 of the present embodiment, the oil stain is first absorbed by the second fiber layer 2 having the wiping surface. After that, the oil stains carried on the second fiber layer 2 are drawn into the first fiber layer 1 due to the difference in capillary pressure between the first fiber layer 1 and the second fiber layer 2. As a result, the oil stains once taken into the second fiber layer 2 are transferred to the first fiber layer 1, and the second fiber layer 2 is in a state where the oil stains can always be wiped off.

The difference between the average interfiber distance of the first fiber layer 1 and the average interfiber distance of the second fiber layer 2 is preferably 0.001 mm or more, more preferably 0.005 mm or more, from the viewpoint of clarifying the difference in capillary force. It is preferable, and more preferably 0.01 mm or more. Further, the difference in the average interfiber distance is preferably 10 mm or less, more preferably 1 mm or less, still more preferably 0.5 mm or less, from the viewpoint of the stability of the liquid film formed between the fibers. Specifically, 0.001 mm or more and 10 mm or less are preferable, 0.005 mm or more and 1 mm or less are more preferable, and 0.01 mm or more and 0.5 mm or less are further preferable.

In addition to the above difference in average fiber distance, as described above, both the first fiber layer 1 and the second fiber layer 2 have embossed recesses 31 and 32 compacted by the recess wall by compression. Moreover, the embossed recess 32 of the second fiber layer 2 is arranged toward the wiping surface 10A.
As a result, in the wiping sheet 10, as described above, the oil stains on the wiping surface are enhanced, and the oil stains pass near the embossed recesses and easily move from the second fiber layer 2 to the first fiber layer 1. Become. As a result, a flow of oil stains (flow of oil stains Q as shown by arrows A1 to A5 in FIGS. 2A and 2B) is completed in the thickness direction of the wiping sheet, and the oil transferability and wiping property of the wiping sheet are completed. Is improved. Then, the spread of oil stains can be suppressed in the contact range of the wiping sheet 10 with the surface to be cleaned.
The embossed recess 31 of the first fiber layer 1 and the embossed recess 32 of the second fiber layer 2 are not limited to the case where they are completely at the same position in the thickness direction. As shown in FIG. 2B, for example, the embossed recess 31 and the embossed recess 32 may be arranged so as to be offset from each other within the range that can contribute to the oil transferability and the wiping property.

In both the first fiber layer 1 and the second fiber layer 2, the embossed recesses 31 and 32 may be on one side or both sides. Further, the embossed recess may penetrate the first fiber layer 1 or the second fiber layer 2 in the thickness direction to form a hole.

In the second fiber layer 2, the embossed recess 32 may be present on the wiping surface 10A (lower surface side) other than the wiping surface 10A (lower surface side), and may be present on the upper surface 10B side, for example, as long as it is on the wiping surface 10A (lower surface side). Further, the embossed recess 32 may penetrate the second fiber layer 2 in the thickness direction, and the second fiber layer 2 may have the embossed recesses on the lower surface side and the upper surface side (not shown).

In the first fiber layer 1, the embossed recess 31 is preferably on the wiping surface 10A (lower surface) side as shown in FIG. The embossed recess on the lower surface side of the first fiber layer 1 improves the oil transferability and wiping property of the wiping sheet.
On the other hand, in the first fiber layer 1, as shown in FIG. 3, the embossed recess may be on the upper surface side opposite to the wiping surface 10A side. Similarly, the embossed recess 31 on the upper surface 10B side of the first fiber layer 1 can also improve the oil transferability and wiping property of the wiping sheet.

In the wiping sheet 10 of the present embodiment, it is also preferable that the embossed recesses on the wiping surface of the second fiber layer 2 penetrate the second fiber layer 2 in the thickness direction and reach the first fiber layer 1 ( See FIG. 4). In this case, the first fiber layer 1 has an embossed recess on the lower surface side. In such an embodiment in which the first fiber layer 1 and the second fiber layer 2 are integrally formed to form a series of embossed recesses, when oil stains are transferred from the second fiber layer 2 to the first fiber layer 1, the oil stains are transferred from the second fiber layer 2 to the first fiber layer 1. The movement of oil stains in the plane direction can be reduced, and the oil stains can be quickly transferred in the thickness direction.

The embossed recess 32 of the second fiber layer 2 constituting the wiping surface preferably has a size of 0.01 mm or more, preferably 0.05 mm or more, when viewed in a plan view from the viewpoint of oil stain uptakeability. Is more preferable, and 0.1 mm or more is further preferable. Further, from the viewpoint of the number of embossed recesses, the size of the embossed recesses 32 is preferably 10 mm or less, more preferably 8 mm or less, and further preferably 5 mm or less when viewed in a plan view. Specifically, it is preferably 0.01 mm or more and 10 mm or less, more preferably 0.05 mm or more and 8 mm or less, and further preferably 0.1 mm or more and 5 mm or less.
Further, the depth of the embossed recess 32 of the second fiber layer 2 is preferably 0.01 mm or more, more preferably 0.05 mm or more, still more preferably 0.1 mm or more, from the viewpoint of suppressing the spread of the wiped oil stains. Further, the depth of the embossed recess 32 is preferably 10 mm or less, more preferably 8 mm or less, still more preferably 5 mm or less, from the viewpoint of workability. Specifically, it is preferably 0.01 mm or more and 10 mm or less, more preferably 0.05 mm or more and 8 mm or less, and further preferably 0.1 mm or more and 5 mm or less.

It is preferable that the embossed recess 31 of the first fiber layer 1 on the upper surface side also has the same size and depth as the embossed recess 32 of the second fiber layer 2 described above in a plan view.

(Measuring method of embossed recesses 32 and 31)
The size of the embossed recess 32 in a plan view can be measured using an optical microscope (for example, a digital microscope (trade name) manufactured by KEYENCE) with the wiping surface viewed in a plan view. When the embossed 31 is exposed on the upper surface side of the first fiber layer 1, it can be measured by the same method as described above. When the embossed recess 31 is directed to the second fiber layer 2 side of the first fiber layer 1, the wiping sheet to be measured is cut out for each layer by a cutting means such as a razor blade, and the measurement is performed by the same method as described above. be able to.
Further, the depths of the embossed recesses 32 and 31 can be measured by the same method as described above by cutting out the cross section of the wiping sheet to be measured in the thickness direction by a cutting means such as a razor blade.

The embossed recess can be formed by various commonly used methods. For example, thermal embossing treatment, ultrasonic embossing treatment and the like can be mentioned.
In the present embodiment, the first fiber layer 1 and the second fiber layer 2 may be individually embossed and then laminated, or the first fiber layer 1 and the second fiber layer 2 are laminated and integrated. The sheet may be embossed. In particular, in order to form a series of embossed recesses that penetrate the second fiber layer 2 and reach the first fiber layer 1, embossing is performed after laminating the first fiber layer 1 and the second fiber layer 2. Is preferable.

The fibers constituting the first fiber layer 1 and the second fiber layer 2 used in the present embodiment are not particularly limited as long as the oil transferability and wiping property of the wiping sheet of the present embodiment are not impaired. For example, polyester, polyamide, polyolefin, cellulose fiber, and fibers made from various metals, glass, and minerals are typical. Of these, polyester, polyamide, polyolefin, and cellulose fiber are preferable. Further, these mixed fibers, for example, polyethylene / polyethylene terephthalate, polypropylene / polyethylene terephthalate and the like can also be mentioned.
Among the above fibers, polyethylene terephthalate, polypropylene, acrylic resin, nylons and cellulose fibers are more preferable. The acrylic resin (particularly acrylic acid) preferably has an ester thereof, methacrylic acid or a repeating unit obtained from the ester thereof.

The wiping sheet of the present invention can be used without particular limitation on various types of surfaces to be cleaned as long as it is accompanied by wiping off oil stains. For example, it can be used for wiping buildings such as floors and walls, cabinets, windowpanes, mirrors, doors, fittings such as doorknobs, furniture such as rugs, carpets and desks, kitchens and toilets. It can also be used as a cleaning wiper, and can also be used for cleaning the face and body, sanitary goods, civil engineering, packaging, etc.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

(Example of manufacturing fiber layer)
The fiber layers A and B used in each of the examples and comparative examples described later were manufactured as follows.

(Fiber layer A)
Using polypropylene resin pellets (Moplen HP461Y (trade name), manufactured by Lyondell Basell) with a melt flow rate (MFR) of 1300 g / 10 min (230 ° C, 2.16 kg), die air flow rate 300 Nm ³ / hr, hot air velocity 79.8 m. A sheet-shaped fiber layer A was produced by the melt blown method under the conditions of / s and a conveyor speed of 5 m / mim.

(Fiber layer B)
A sheet-shaped fiber layer B was produced in the same manner as the fiber layer A except that the die air flow rate was 100 Nm ³ / hr and the hot air velocity was 26.6 m / s.

The fiber diameters, sheet thicknesses, and basis weights of the obtained fiber layers A and B were as follows.
(1) Fiber diameter Fiber layer A: 4.25 μm Fiber layer B: 14.11 μm
For the fiber layer A, JSM-6510 (trade name, manufactured by JEOL Ltd.) is used as a scanning electron microscope (SEM), and for the fiber layer B, VHX-1000 (trade name, Keyence) is used as an optical microscope. Manufactured by).
(2) Sheet thickness Fiber layer A: 437.27 μm Fiber layer B: 526.93 μm
The measurement was performed using a micrometer SMD-565 (trade name, manufactured by TECLOCK) as a thickness gauge.
(3) Basis weight Fiber layer A: 48.24 g / m ² Fiber layer B: 46.37 g / m ²
The measurement was performed using a balance GH-202 (trade name, manufactured by A & D Co., Ltd.).
(4) Specific gravity The specific gravity was 0.886 g / ml as measured by a pycnometer for polypropylene resin pellets as a raw material.

(5) Average interfiber distance Based on the measured values of (1) to (4) above, the average interfiber distance of each of the fiber layers A and B was calculated using the above formula [I].
Fiber layer A: 10.68 μm Fiber layer B: 39.68 μm
That is, the fiber layer B had a larger inter-fiber distance than the fiber layer A.

In each Example and each Comparative Example, each wiping sheet sample was prepared as follows using the above fiber layers A and B.

(Example 1)
Using an embossed mold having a cylinder diameter of 76 mm, a mold width of 205 mm, and an area ratio of 22.5%, one side of each of the fiber layer A and the fiber layer B was embossed. At this time, the processing speed was 3 m / min, the pressure was 2.48 kg / cm ² , and the linear pressure was 0.005488 MPa.
After the embossing treatment, the fiber layer B was used as a fiber layer constituting the wiping surface, and the fiber layer A was laminated on the fiber layer. At that time, both the embossed recess of the fiber layer B and the embossed recess of the fiber layer A were arranged so as to face the wiping surface side. Further, the fiber layer B and the fiber layer A were joined by heat fusion. In this way, the wiping sheet sample of Example 1 was prepared.

(Example 2)
When the fiber layer B and the fiber layer A were laminated, the wiping sheet sample of Example 2 was prepared in the same manner as in Example 1 except that the embossed recesses of the fiber layer A were laminated so as to be arranged on the upper surface side. Made.

(Example 3)
Before the embossing treatment, the fiber layer B and the fiber layer A were laminated by heat fusion and integrated.
The wiping surface side of the integrated sheet (the surface on the side where the fiber layer B is arranged) was embossed under the same conditions as in Example 1 to prepare a wiping sheet sample of Example 3. In the wiping sheet sample of Example 3, the embossed recess penetrated the fiber layer B and reached the fiber layer A.

(Comparative Example 1)
Two fiber layers A not subjected to the embossing treatment were laminated to prepare a wiping sheet sample of Comparative Example 1.

(Comparative Example 2)
Two fiber layers B not subjected to the embossing treatment were laminated to prepare a wiping sheet sample of Comparative Example 2.

(Comparative Example 3)
A wiping sheet sample of Comparative Example 3 was prepared in the same manner as in Example 1 except that the fiber layer B and the fiber layer A were not embossed.

(Comparative Example 4)
The wiping sheet sample of Comparative Example 4 was prepared in the same manner as in Example 1 except that two fiber layers A were laminated instead of the fiber layer B and the fiber layer A. In this sample, the embossed recesses of the two laminated fiber layers A were arranged toward the wiping surface side.

(Comparative Example 5)
The wiping sheet sample of Comparative Example 5 was prepared in the same manner as in Example 1 except that two fiber layers B were laminated instead of laminating the fiber layer B and the fiber layer A. In this sample, the embossed recesses of the two laminated fiber layers B were arranged toward the wiping surface side.

(Comparative Example 6)
When the fiber layer B and the fiber layer A were laminated, the embossed recesses of the fiber layer B were arranged and laminated toward the upper surface side opposite to the wiping surface in the same manner as in the first embodiment. A wiping sheet sample of Comparative Example 6 was prepared.

(Comparative Example 7)
When the fiber layer B and the fiber layer A are laminated, the same as in Example 1 except that the embossed recesses of the fiber layer B and the embossed recesses of the fiber layer A are both arranged and laminated toward the upper surface side. Then, the wiping sheet sample of Comparative Example 7 was prepared.

(Comparative Example 8)
A wiping sheet sample of Comparative Example 8 was prepared in the same manner as in Example 1 except that the fiber layer B was not embossed.

(Comparative Example 9)
A wiping sheet sample of Comparative Example 9 was prepared in the same manner as in Example 1 except that the fiber layer A was not embossed.

(Comparative Example 10)
Except that the embossing treatment was performed on the upper surface side (the surface on which the fiber layer A is arranged) instead of the wiping surface side (the surface on which the fiber layer B is arranged) of the integrated sheet. A wiping sheet sample of Comparative Example 10 was prepared in the same manner as in Example 3. In the wiping sheet sample of Comparative Example 10, the embossed recess penetrated the fiber layer A and reached the fiber layer B.

(test)
The following tests (1) to (3) were performed on each of the above samples in an environment with a room temperature of 20 ° C. and a humidity of 65%.

(1) Oil retention amount (oil absorption, oil transferability between fiber layers)
In advance, the sample was cut into a size of 5 cm square, and the fiber layer A and the fiber layer B were weighed separately.
As a sample of oil stains, 1 μL (about 30 mg) of colored oleic acid droplets are dropped on a composite flow long floor material, and a 5 cm square sample (laminate of fiber layer B and fiber layer A) is placed on the wiping surface (wiping surface). It was covered from the fiber layer B side). A weight of 550 g was placed on the sample, left for 5 seconds, and then the fiber layer A and the fiber layer B were weighed separately again.
The mass of each fiber layer of the sample before and after sucking the oleic acid droplets was compared, and the amount of oil retained in each fiber layer of the sample was evaluated. The reason why oleic acid is used as the oil stain is that it is a common component of sebum stain in a general living environment.

(2) Wiping property The sample was cut out to a size of 5 cm square.
As a sample of oil stains, 1 μL (about 30 mg) of stained oleic acid droplets was dropped on a composite flooring material, and a 5 cm square sample was placed on the composite flow long floor material. While placing a 550 g weight on the sample, perform a wiping operation for 5 seconds in a circular motion to check whether the oleic acid droplets have been wiped off from a white fluorescent lamp 190 cm away from the composite flow long floor material. The degree of light reflection was visually confirmed and evaluated according to the following criteria.
4: The oleic acid droplets can be wiped off within 3 seconds to the extent that reflection cannot be confirmed (to the extent that the shine of the oil cannot be visually recognized).
3: The oleic acid droplets can be wiped off to the extent that reflection cannot be confirmed (to the extent that the shine of the oil cannot be visually recognized), but it takes more than 3 seconds.
2: The shine of the oil remains, and the oleic acid droplets cannot be completely wiped off.
1: There is a lot of oil shine and a lot of oleic acid droplets remaining.

(3) Evaluation of liquid spreading A sample was cut out to a size of 5 cm square.
As a sample of oil stains, 3 mg of colored oleic acid was added dropwise to the composite flooring material. A 5 cm square sample and a 500 g weight were placed on it and left for 3 seconds. Then, the sample was moved together with the weight at a speed of 8 cm per second for 40 cm (5 seconds) in one direction, and the sample and the weight were immediately removed from the composite flooring. Next, the removed sample and weight are placed on a composite flooring material to which oleic acid has not been dropped, and the sample and weight are moved at the same speed by 40 cm (5 seconds), and the sample and weight are immediately removed from the composite flooring material. Removed. Such wiping work was performed a total of 4 times (total moving distance: 160 cm), and the distance at which oleic acid was extended was measured.
The measurement was performed 3 times for each sample, and the liquid spread was evaluated by the average value of the measured values of the 3 times.
The smaller the measured value, the better the wiping property.

The results are shown in Table 1. In the table, "-" indicates that there is no embossing in the item of the position of the embossed recess, and the first fiber layer 1 and the second fiber layer 2 are fused in the item of oil retention evaluation. Each shows that it is difficult to measure.

As is clear from Table 1, in Comparative Examples 1 and 2 in which there is no difference in the distance between the fibers between the fiber layers, the transferability of the oil from the fiber layer on the wiping surface side to the fiber layer on the upper surface side is poor, and the oil on the floor surface is poor. The wiping property was so bad that a lot of shine remained. Therefore, it was 160 cm, which was the worst in the liquid spreading on the floor surface by wiping. Further, Comparative Examples 3, 8 and 9 which do not satisfy the requirement that the embossed recesses are provided in both layers, Comparative Examples 4 and 5 which have the embossed recesses but have no difference in the distance between the fibers between the fiber layers, and the embossed recesses are the first. In Comparative Examples 6, 7 and 10 which did not have on the wiping surface (lower surface) side of the 2 fiber layer 2, the oil transferability to the fiber layer on the upper surface side was not sufficient, and the wiping property was inferior. Furthermore, in the liquid spreading evaluation, it could not be suppressed within 40 cm (it cannot be wiped off by one wiping operation).
On the other hand, in Examples 1 to 3, which are the wiping sheets of the present invention, the fiber layer on the upper surface side absorbs three times or more more oleic acid than the fiber layer on the wiping surface side, and the fiber layer on the upper surface side. It had a high oil transferability to. In addition, in Examples 1 to 3, the oleic acid droplets could be quickly wiped off within 3 seconds, showing high wiping performance. Further, in Examples 1 to 3, the liquid spreading evaluation was 6 cm or less in each case, the spread of oil stains due to wiping was suppressed to an extremely small size, and it was difficult to leave oil stains on the cleaning surface.

1 1st fiber layer 2 2nd fiber layer 10 Wiping sheet 10A Wiping surface 10B Top surface 31, 32 Embossed recess

Claims (6)

A wiping sheet in which multiple fiber layers are laminated,
The fiber layer constituting the wiping surface of the wiping sheet has a larger interfiber distance than the other fiber layers.
Each of the plurality of fiber layers has an embossed recess, and the embossed recess of the fiber layer constituting the wiping surface is arranged toward the wiping surface.
In the fiber layer constituting the wiping surface and the other fiber layers, fiber compaction portions are arranged in the thickness direction around the wall of the recess of the embossed recess, respectively.
The fiber layer constituting the wiping surface has a flat surface facing the other fiber layer, and the fiber layer portion including the fiber compaction portion of the fiber layer constituting the wiping surface is flat. A wiping sheet that is directly laminated with a fiber layer portion including the fiber compaction portion of the other fiber layer via a surface . The wiping sheet according to claim 1, wherein the other fiber layer has the embossed recess on the surface on the wiping surface side. The wiping sheet according to claim 1 or 2, wherein the embossed recess of the fiber layer constituting the wiping surface is arranged so as to penetrate through the other fiber layer. The wiping sheet according to any one of claims 1 to 3, wherein the other fiber layer has the embossed recess on the surface opposite to the wiping surface side. The wiping sheet according to any one of claims 1 to 4, wherein the embossed recess of the fiber layer constituting the wiping surface has a size of 0.01 mm or more and 10 mm or less when viewed in a plan view. Claim 1 in which, in each of the fiber layer constituting the wiping surface and the other fiber layer, the fiber layer portion including the fiber compaction portion in the region between the embossed recesses is a solid convex portion. The wiping sheet according to any one of 5 to 5.

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