CN111031880B

CN111031880B - Wiping sheet and method for producing same

Info

Publication number: CN111031880B
Application number: CN201880050906.0A
Authority: CN
Inventors: 成田行人; 金田学; 百合野翔太郎
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2017-08-09
Filing date: 2018-07-19
Publication date: 2021-05-25
Anticipated expiration: 2038-07-19
Also published as: CN111031880A; TWI780197B; JP2019030572A; MY195600A; TW201920793A; SG11202000529VA; WO2019031180A1; JP6917242B2

Abstract

A wiping sheet (10) is provided with a fiber assembly in which 1 st fibers (20) and 2 nd fibers (40) having a smaller diameter than the 1 st fibers are interwoven, and has a 1 st surface (50Y) as a wiping surface and a 2 nd surface (50X) on the opposite side thereof. The 2 nd fibers (40) are present at a higher ratio on the 1 st side than on the 2 nd side. A plurality of projections (50A) are formed on the 1 st surface (50Y) side, and the 1 st fibers (20) are present at a higher ratio than the 2 nd fibers (40) at the top (50T) of the projections (50A) with respect to the entire fibers constituting the projections (50A) at the top (50T) of the projections (50A). At the bottom (50B) of the projection (50A), the presence ratio of the 2 nd fibers (40) in the bottom (50B) is higher than the presence ratio of the 1 st fibers (20) with respect to the entire fibers constituting the projection (50A).

Description

Wiping sheet and method for producing same

Technical Field

The present invention relates to a wiping sheet and a method for producing the same.

Background

Various attempts have been made to improve the function of nonwoven fabrics by forming a rough structure on the surface of the nonwoven fabric. For example, patent document 1 describes a nonwoven fabric formed by depositing polymer fibers of at least one of nanofibers and microfibers by an electrospinning method, and having a fine uneven pattern at a specific position on a plane. It is described in the literature that the nonwoven fabric can be used to improve the function by utilizing the shape specificity obtained by the uneven micropattern structure, improve the cell affinity, the material structure, and the like, and adjust the biological functionality.

Patent document 2 describes a nonwoven fabric comprising ultrafine fibers of 1dtex or less and having irregularities on the surface. The surface of the nonwoven fabric includes a fiber bundle in which a plurality of fibers are entangled with each other, and a depression in the vicinity thereof. The number of the ultrafine fibers in the fiber bundle is larger than the number of the ultrafine fibers in the depressions. The nonwoven fabric is described in the literature as being excellent in bulkiness, soft, and soft to the touch when it is in contact with a target surface.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2006-328562

Patent document 2: japanese laid-open patent publication No. 2009-13544

Disclosure of Invention

The present invention provides a wiping sheet:

the wiping sheet comprises a fiber assembly formed by interweaving at least 1 st fiber and 2 nd fiber having a smaller diameter than the 1 st fiber, and has a 1 st surface serving as a wiping surface and a 2 nd surface located on the opposite side of the 1 st surface. The 2 nd fibers are present at a higher ratio on the 1 st side than on the 2 nd side. A plurality of convex portions are formed on the 1 st surface side. The ratio of the 1 st fibers present in the top portion is higher than the ratio of the 2 nd fibers present in the entire fibers constituting the convex portion. The presence ratio of the 2 nd fibers in the bottom portion is higher than the presence ratio of the 1 st fibers with respect to the entire fibers constituting the convex portion.

Further, the present invention provides a method for producing a wiping sheet, comprising:

as a preferred method for producing the wiping sheet, a laminate of a fiber aggregate of the 1 st fibers and a fiber aggregate of the 2 nd fibers having a smaller diameter than the 1 st fibers is arranged such that the fiber aggregate of the 2 nd fibers faces a projection-forming member having a plurality of openings. In this state, a water stream is blown from the fiber aggregate side of the 1 st fiber to interlace the 1 st fiber and the 2 nd fiber, and the fiber aggregate positioned in the opening part is protruded into the opening part.

Drawings

Fig. 1 is an enlarged view of a main part of a convex portion in the wiping sheet of the present invention.

Fig. 2 is a schematic view of an apparatus for producing a wiping sheet of the present invention.

Fig. 3 is a plan view of an embodiment of a projection forming member used in the present invention.

Fig. 4 is an enlarged view of a main part showing a process of manufacturing the wiping sheet of the present invention.

Fig. 5 is a sectional view taken along line a-a of fig. 3.

Fig. 6 is a plan view of another embodiment of the projection forming member used in the present invention.

Fig. 7 is an enlarged partial view (corresponding to fig. 4) showing another step of producing the wiping sheet of the present invention.

Fig. 8 is a sectional view taken along line B-B of fig. 6.

Fig. 9 is a graph of the frictional resistance values of the wet-type wiping sheets in example 1 and comparative example 1.

Fig. 10 is a graph of the frictional resistance values of the dry-type wiping sheets in example 2 and comparative examples 2 and 3.

Detailed Description

As articles for wiping hard surfaces such as floors and furniture, wiping sheets comprising nonwoven fabrics are often used. Patent document 1 describes a technique relating to a nonwoven fabric, but the nonwoven fabric described in the same document is intended to be applied to medical devices such as regenerative medicine, and does not mention the functionality of the nonwoven fabric for wiping or cleaning purposes.

When the nonwoven fabric having the uneven structure described in patent document 2 is used as a cleaning article, the friction resistance between the nonwoven fabric and a cleaning object may be increased due to the inclusion of the fine-diameter fibers in the nonwoven fabric, and the nonwoven fabric may be poor in handling during cleaning.

Therefore, the present invention relates to a wiping sheet which reduces frictional resistance against a wiping object and improves operability during wiping.

The wiping sheet of the present invention will be described below based on preferred embodiments thereof. In the present invention, wiping includes both cleaning and wiping, and includes, for example, cleaning of buildings such as floors, walls, ceilings, and pillars, cleaning of building interior materials and accessories, wiping of articles, and wiping of bodies and body implements.

The wiping sheet of the present invention contains a fiber aggregate. The fibers constituting the fiber assembly include at least the 1 st fiber and the 2 nd fiber having a smaller diameter than the 1 st fiber. Regarding the 1 st fiber and the 2 nd fiber, the 1 st fiber, the 2 nd fiber, and the 1 st fiber and the 2 nd fiber are interwoven to form the fiber aggregate. The fiber aggregate may carry a wiping solution. The wiping solution and the method of supporting the same are described in detail below. In the present specification, when the term "wiping sheet" is simply used, the term "wiping sheet" refers to a sheet carrying wiping liquid or a sheet not carrying wiping liquid, depending on the description.

The fiber aggregate used for the wiping sheet 10 is a fiber aggregate in which the 1 st and 2 nd fibers are mainly entangled and combined. Here, the wiping surface of the wiping sheet 10 is also referred to as a front surface or a 1 st surface, and the surface opposite to the wiping surface is referred to as a back surface or a 2 nd surface.

Fig. 1 shows a wiping sheet according to an embodiment of the present invention with a main portion of a longitudinal section enlarged. As shown in the figure, the wiping sheet 10 includes the 1 st fibers 20 and the 2 nd fibers 40. The wiping sheet 10 has a 1 st surface 50Y and a 2 nd surface 50X located on the opposite side of the 1 st surface 50Y. The 1 st surface 50Y of the wiping sheet 10 is provided as a wiping surface when the wiping sheet 10 is used. As shown in fig. 1, a fiber aggregate of the 2 nd fiber 40, which is a fiber having a small fiber diameter, is present on the upper side of the drawing, and is a wiping surface. Therefore, the lower side of the figure is the opposite side of the wiping surface, the back surface.

The wiping sheet 10 protrudes from the 2 nd surface 50X toward the 1 st surface 50Y, thereby forming a convex portion 50A. A plurality of projections 50A are formed in the surface direction of the wiping sheet 10. The convex portion 50A takes a shape in which the 1 st surface 50Y of the wiping sheet 10 is raised from the flat surface 50Y'. On the 2 nd surface 50X side, a region corresponding to the convex portion 50A is recessed from the flat surface 50X' of the 2 nd surface 50X toward the 1 st surface 50Y to form a concave portion 50C. The entire area of the 2 nd surface 50X can be made flat by the method of manufacturing the wiping sheet 10. In the present specification, the 1 st surface 50Y (wiping surface) is described as not including the convex portion 50A.

Each projection 50A is a solid portion whose inside is filled with the 1 st fiber 20 and/or the 2 nd fiber 40. The shape and size of each projection 50A may be the same or different. In view of the ease of manufacturing the wiping sheet 10, the projections 50A are preferably identical in shape and size.

The protrusions 50A may be regularly arranged on the 1 st surface 50Y side of the wiping sheet 10, or may be irregularly arranged. When the protrusions 50A are regularly arranged on the 1 st surface 50Y, they may be regularly arranged, for example, along the longitudinal direction and/or along the width direction of the wiping sheet 10. In any case where the convex portions 50A are arranged regularly or irregularly, the plurality of convex portions 50A are formed on the 1 st surface 50Y side as the wiping surface, so that the frictional force between the surface to be wiped and the wiping sheet 10 can be effectively reduced when the wiping operation using the wiping sheet 10 is performed, and the wiping operation can be easily performed.

As shown in fig. 1, in the wiping sheet 10, the 1 st fibers 20 and the 2 nd fibers 40 are present in a biased manner in the longitudinal sectional view. Specifically, the 2 nd fibers 40 of the wiping sheet 10 are present at a higher ratio on the 1 st surface 50Y as the wiping surface than on the 2 nd surface 50X as the surface opposite to the wiping surface. With this configuration, the wiping effect of the wiping sheet 10 can be improved by forming the plurality of projections 50A on the 1 st surface 50Y side.

As described above, the 2 nd fibers 40 of the wiping sheet 10 are present at a higher ratio on the wiping surface than on the surface opposite to the wiping surface. When focusing on the 1 st surface 50Y as the wiping surface, the 1 st fibers 20 are present in the top 50T of the projection 50A formed on the 1 st surface 50Y side at a higher ratio than the 2 nd fibers 40 with respect to the entire fibers constituting the projection 50A. On the other hand, in the bottom portion 50B of the projection 50A, the presence ratio of the 2 nd fibers 40 in the bottom portion 50B is higher than the presence ratio of the 1 st fibers 20 with respect to the entire fibers constituting the projection 50A. By setting the presence ratio of the 1 st and 2

nd fibers

20 and 40 constituting the convex portion 50A to the above-described condition, it has been unexpectedly found that the frictional force between the surface to be wiped and the wiping sheet 10 can be effectively reduced.

The frictional force between the surface to be wiped and the wiping sheet 10 is preferably 10cm × 25Application of 55N/m to cm-sized wiping sheet 10²The resistance to wiping of the surface to be wiped with the pressure of (3) is 10N or less, more preferably 5N or less, and still more preferably 4N or less. The lower limit of the resistance is not particularly limited, and the lower the resistance, the better, if the resistance is as low as about 0.8N, the wiping operation can be smoothly performed.

The resistance at the time of wiping was measured specifically by the following method. An alligator type jig was attached to the tip of a tension and pressure gauge (RX-20, manufactured by Aikoh Engineering), and the head of a quick wiper (manufactured by kao corporation) equipped with a wiping sheet having a size of 285mm × 205mm was attached to the jig. The resistance was measured as the maximum load recorded on a pull pressure gauge when the head was placed on a floor (Conbit new advance101, manufactured by WOODONE corporation) and scanned for 1m at a speed of 1 cm/sec.

The top 50T of the projection 50A is a region from the apex of the projection 50A to (1/3) H when the height of the projection 50A is H. On the other hand, the bottom 50B of the projection 50A is a region from the flat surface 50Y' of the 1 st surface 50Y to (1/3) H.

From the viewpoint of more effectively reducing the frictional force between the surface to be wiped and the wiping sheet 10, the ratio of the 1 st fibers 20 and the 2 nd fibers 40 at the top portions 50T of the protrusions 50A is preferably 3 times or more the number of the 1 st fibers as compared with the number of the 2 nd fibers in the entire fibers constituting the protrusions 50A. From the same viewpoint, the presence ratio of the 1 st fibers 20 and the 2 nd fibers 40 in the bottom portion 50B of the projection 50A is preferably 2 or more times the number of the 2 nd fibers as compared with the number of the 1 st fibers in terms of the number of the entire fibers constituting the projection 50A.

The frictional force between the surface to be wiped and the wiping sheet 10 may depend on the shape of the convex portion 50A. From the viewpoint of more effectively reducing the frictional force, the width W of the convex portion 50A is preferably 400 μm or more, more preferably 800 μm or more, and still more preferably 900 μm or more. The width W is preferably 10mm or less, more preferably 8mm or less, and still more preferably 5mm or less. The width W is preferably 400 μm to 10mm, more preferably 800 μm to 8mm, and still more preferably 900 μm to 5 mm. As shown in fig. 1, the width W is measured with a position where the convex portion 50A starts to rise from the flat surface 50Y' of the 1 st surface 50Y of the wipe sheet 10 as a starting point. When focusing attention on 1 convex portion 50A, the width W of the convex portion 50A means the widest width to be measured when the measured width W of the convex portion 50A is different in any direction. When attention is paid to the plurality of convex portions 50A, the width W of the convex portion 50A is an arithmetic average of the widths of the convex portions 50A to be measured when the measured widths of the convex portions 50A are different from each other.

From the same viewpoint, the height H of the projection 50A is preferably 110 μm or more, more preferably 500 μm or more, and still more preferably 900 μm or more. The height H is preferably 25mm or less, more preferably 20mm or less, and still more preferably 18mm or less. The height H is preferably 110 μm or more and 25mm or less, more preferably 500 μm or more and 20mm or less, and still more preferably 900 μm or more and 18mm or less. As shown in fig. 1, the height H is a distance from the flat surface 50Y' of the 1 st surface 50Y of the wipe sheet 10 to the apex of the convex portion 50A. When focusing attention on the plurality of convex portions 50A, the height of each convex portion 50A is an arithmetic average of the heights of the convex portions 50A to be measured when the heights of the convex portions 50A are different from each other.

The formation density of the convex portions 50A on the 1 st surface 50Y side may also affect the frictional force between the surface to be wiped and the wiping sheet 10. From the viewpoint of more effectively reducing the frictional force, when a virtual circle having a diameter of 20mm is drawn at an arbitrary position on the 1 st surface 50Y, the number of the convex portions 50A present in the virtual circle is preferably 10 or more, more preferably 15 or more, and still more preferably 20 or more. The number of the projections 50A is preferably 60 or less, more preferably 50 or less, and still more preferably 40 or less. The number of the convex portions 50A is preferably 10 or more and 60 or less, more preferably 15 or more and 50 or less, and further preferably 20 or more and 40 or less.

The wiping sheet 10 of the present invention may be a dry wiping sheet in which wiping liquid is not carried (hereinafter, this embodiment is also referred to as a "dry wiping sheet"), or may be a wet wiping sheet in which wiping liquid is carried (hereinafter, this embodiment is also referred to as a "wet wiping sheet"). When the wiping sheet 10 of the present invention is a wet wiping sheet, it is preferable that the wiping liquid is carried on at least the fiber assembly located on the 2 nd surface side. Further, the term "wiping solution is carried on at least the fiber aggregate located on the 2 nd surface side" means that: the embodiment in which the fiber aggregate on the opposite side of the wiping surface contains the wiping liquid also includes the embodiment in which the fiber aggregate on the wiping surface side contains the wiping liquid also in the gap. Further, the wiping solution is preferably carried in a large amount in the fiber aggregate on the opposite side of the wiping surface.

In particular, when the wiping sheet 10 of the present invention is a wet wiping sheet, it is advantageous in that the effect of reducing the frictional resistance during wiping becomes more remarkable because the ratio of the 1 st fibers 20 and the 2 nd fibers 40 at the top portions 50T and the bottom portions 50B of the protrusions 50A, the width W and the height H of the protrusions 50A on the 1 st surface 50Y side, and/or the formation density of the protrusions 50A satisfy specific ranges in addition to the formation of the plurality of protrusions 50A.

In view of further improving the wiping effect of the wiping sheet 10 by forming the plurality of protrusions 50A and in view of stably supporting a large amount of wiping liquid when the wet wiping sheet 10 is used, the area ratio of the 2 nd fibers in the wiping surface of the wiping sheet 10 including the voids is preferably 40% to 99%, more preferably 45% to 95%, and further preferably 50% to 90%. On the other hand, the area ratio of the 2 nd fibers in the surface opposite to the wiping surface is preferably 0% or more and 55% or less. The area occupied by the 2 nd fibers in the wiping surface is obtained by measuring the area occupied by the fibers having a small fiber diameter from an image or photograph obtained by taking an image of the wiping surface, for example. Hereinafter, the area occupied by the fibers can be determined in the same manner as described above. Therefore, the area ratio is a value obtained by dividing the area occupied by the fibers by the area to be measured. In the case of% expression, the value is 100 times the value obtained by division.

Here, for example, the remaining 1% of 99% of the upper limit of the area ratio of 40% or more and 99% or less is a void. This void is necessary to release the wiping solution to the wiping surface when the wet wiping sheet 10 is used. By adjusting the ratio of the voids, particularly when the wet-type wiping sheet 10 is used, the amount of wiping liquid released for wiping off stains on the surface to be wiped can be suppressed to a necessary amount even if wiping is performed with force. Further, by providing the area ratio occupied by the 2 nd fibers in the surface opposite to the wiping surface in the above manner, as a result, the number of voids increases, and the amount of wiping liquid carried in the wet wiping sheet 10 increases. If the area ratio of the 2 nd fibers in the wiping surface is too small, the wiping liquid is discharged in an amount more than necessary. Therefore, the erasable area becomes small.

In the wiping sheet 10, the area ratio of the 2 nd fibers 40 in the plane parallel to the wiping surface preferably decreases stepwise, curvilinearly, or in combination thereof in the thickness direction on the opposite side of the wiping surface. In particular, by setting the region of 50% or more and 100% or less of the thickness of the wiping sheet 10 from the surface opposite to the wiping surface to the area ratio occupied by the 2 nd fibers 40 in the range of 50% or more and 100% or less, the amount of wiping liquid to be carried can be increased when the wet wiping sheet 10 is used. Here, the ratio of the thickness where the area ratio of the 2 nd fibers 40 is 50% or more and 100% or less is preferably 1% or more and 90% or less, more preferably 5% or more and 70% or less, and further preferably 7% or more and 50% or less. By setting the thickness ratio to a preferable value as described above, the wiping liquid released for wiping the surface to be wiped with dirt can be released in a necessary amount in the case of the wet wiping sheet 10. The thickness of the wiping sheet 10 is, as shown in fig. 1, the distance T from the surface opposite to the wiping surface to the apex of the convex portion 50A.

Here, to obtain internal information of the wiping sheet 10, a confocal laser microscope may be used. By using a confocal laser microscope, a spectrum in the sample can be obtained, and by performing raman imaging on the sample in the depth direction, for example, the distribution of components in the sample can be observed without being destroyed.

The wet-type wiping sheet 10 includes at least 2 layers of a liquid retaining layer for supporting a wiping liquid and a release layer for the wiping liquid, the release layer including a wiping surface. In particular, in order to carry a large amount of wiping liquid, as described above, the region of 50% to 100% of the thickness of the wiping sheet 10 from the surface opposite to the wiping surface is set so that the area ratio occupied by the 2 nd fibers is 1% to 100%. This makes it possible to provide a liquid retaining layer for supporting a large amount of wiping liquid. On the other hand, the release layer is a portion other than the liquid retention layer including the wiping surface.

The wiping sheet 10 preferably has a higher capillary pressure on the wiping surface side than on the opposite side of the wiping surface. Accordingly, particularly when used as the wet-type wiping sheet 10, the amount of wiping liquid released for wiping the surface to be wiped can be controlled to a necessary amount even if wiping is performed with a large force during wiping. Therefore, in the case of wiping a carpet tile (rug), carpet (carpet), floor, or the like having a large wiping area, it is not necessary to replace the wiping sheet 10 with a new one during wiping, or the number of replacements can be reduced.

Here, the capillary pressure is known from the following relationship.

Pc＝2kγ_L/r×cosθ

Wherein Pc is the capillary pressure (N/m) of the fiber aggregate²)，γ_LThe surface tension (N/m) of the liquid, θ the contact angle (rad) of the fiber and the liquid, r the fiber diameter (m), and k the correction factor.

Pc derived by the above equation is a value using a summary statistic derived by measurement of the fiber aggregate. To measure Pc, it is necessary to measure the surface tension of the liquid, the fiber diameter, the contact angle of the fiber with the liquid, and the calibration coefficient. The surface tension is an average value obtained by measuring 10 times in an environment of 20 ℃ and 65% R.H. by an automatic surface tension meter based on the plate method such as DY-200 manufactured by Kyowa interface science. The fiber diameter was an average value obtained by measuring the fiber diameter of 150 fibers by measuring 30 fibers per observation at an observation magnification of 350 times, randomly observing 5 sites in total, and observing the fiber diameter by a scanning electron microscope. The contact angle of the fiber with the liquid is: constituent fibers of the fiber aggregate were identified by fourier transform infrared spectroscopy (FTIR), and the contact angle on a resin flat plate of the same composition was measured. Specifically, the contact angle was measured at 5 positions on a flat plate using a fully automatic contact angle meter such as DMo-901 manufactured by Kyowa interface science, and the contact angle was measured at 3 seconds after 1. mu.L of the mixture was dropped, and the average value was obtained. When there are a plurality of fiber materials, the contact angle is measured in the same manner for each material, and as a value at the time of Pc calculation, a value obtained by weighting the average contact angle based on the surface area ratio of each fiber component is represented by θ in the formula. The correction coefficients are: the capillary pressure Pc was derived by measuring the Klemm water absorption specified in JIS P8141, measuring the water absorption weight of the liquid from the water absorption height and dividing the water absorption weight by the total amount of the capillary cross-section constituting the nonwoven fabric, and the correction coefficient k was calculated from the Pc measured in this manner.

As is clear from the above formula, the capillary pressure increases as the fiber diameter decreases. The wiping sheet 10 is reduced in fiber diameter to increase the capillary pressure on the wiping surface side.

The fibers constituting the wiping sheet 10 are at least 2 types of fibers different in fiber diameter. The fibers are independent of each other, and are represented by polyester, polyamide, polyolefin, cellulose fibers, or fibers made of various metals, glasses, and minerals. Among them, polyester, polyamide, polyolefin, and cellulose fiber are preferable.

The polyester may be any polyester as long as it has an ester bond in the polymer main chain. Examples thereof include: polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN).

The polyolefin is obtained from a monomer having an ethylenically unsaturated group. Examples thereof include: polyethylene, polypropylene, ethylene-propylene copolymer, polyvinyl acetate, ethylene-vinyl acetate copolymer, cyclic acetal of polyvinyl alcohol, acrylic resin (including acrylic resin and methacrylic resin), polyvinyl chloride. Polyolefins As mentioned above, both homopolymers and copolymers may be used.

The polyamide may be any polyamide as long as it has an amide bond structure in the polymer main chain. Examples thereof include: condensation nylons such as nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 612, nylon 6T, nylon 6I, nylon 9T, nylon M5T. Further, a polyamide obtained by using the following diamine component and dicarboxylic acid component can be exemplified.

As the diamine component, there can be mentioned: aliphatic diamine compounds such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2, 4-trimethyl-hexamethylenediamine, and 2,4, 4-trimethyl-hexamethylenediamine. Further, there may be mentioned: alicyclic diamine compounds such as 1, 3-bis (aminomethyl) cyclohexane, 1, 4-bis (aminomethyl) cyclohexane, 1, 3-diaminocyclohexane, 1, 4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2-bis (4-aminocyclohexyl) propane, bis (aminomethyl) decahydronaphthalene, and bis (aminomethyl) tricyclodecane. Further, there may be mentioned: diamine compounds having an aromatic ring such as m-xylylenediamine, p-xylylenediamine, bis (4-aminophenyl) ether, p-phenylenediamine, and bis (aminomethyl) naphthalene.

Examples of the carboxylic acid component include: aliphatic dicarboxylic acid compounds such as succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid. Further, phthalic acid compounds such as isophthalic acid, terephthalic acid, and phthalic acid are exemplified. Further, there may be mentioned: naphthalenedicarboxylic acid compounds such as 1, 2-naphthalenedicarboxylic acid, 1, 3-naphthalenedicarboxylic acid, 1, 4-naphthalenedicarboxylic acid, 1, 5-naphthalenedicarboxylic acid, 1, 6-naphthalenedicarboxylic acid, 1, 7-naphthalenedicarboxylic acid, 1, 8-naphthalenedicarboxylic acid, 2, 3-naphthalenedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid and 2, 7-naphthalenedicarboxylic acid.

Also included are nylons, and these diamine components and dicarboxylic acid components may be used alone or in combination.

The cellulose fiber may be natural fiber or synthetic fiber, and examples of the synthetic fiber include cellulose acylate such as acetate.

Further, a mixed fiber of these, for example, polyethylene/polyethylene terephthalate, polypropylene/polyethylene terephthalate, and the like can be cited.

In the present invention, among the fibers, polyethylene terephthalate, polypropylene, acrylic resins, nylons, and cellulose fibers are more preferable. The acrylic resin (particularly acrylic acid) preferably has a repeating unit obtained from an ester thereof, methacrylic acid or an ester thereof.

The fiber length of the fibers, that is, the average fiber length of the entire fibers used in the present invention varies depending on the method for producing the fibers, and is generally preferably 1mm or more and 100mm or less, more preferably 10mm or more and 90mm or less, and further preferably 20mm or more and 60mm or less.

The diameter of the 1 st fiber 20 is preferably 10 μm or more and 30 μm or less, and more preferably 15 μm or more and 25 μm or less. On the other hand, the diameter of the 2 nd fibers 40 is preferably 0.1 μm or more and 9 μm or less, and more preferably 0.5 μm or more and 5 μm or less.

The fibers having different fiber diameters may be fibers having the same composition as each other or fibers having different compositions, and the fibers having the same composition are preferable in the present invention. The fiber length may be different from or the same as each other, and fibers having the same fiber length are preferable in the present invention.

The weight per unit area and the wiping surface side of the fibers constituting the wiping sheet 10 are preferably 1g/m²Above and 100g/m²Hereinafter, more preferably 5g/m²Above and 50g/m²Hereinafter, more preferably 10g/m²Above and 30g/m²The following. On the other hand, the surface opposite to the wiping surface is preferably 10g/m²Above and 50g/m²Hereinafter, more preferably 15g/m²Above and 30g/m²Hereinafter, more preferably 20g/m²Above and 25g/m²The following.

In relation to the basis weight of the fibers constituting the wiping sheet 10, the thickness T of the wiping sheet 10 is preferably 1mm or more, more preferably 1.2mm or more, and still more preferably 1.5mm or more under a load of 40 Pa. Further, under the same load, it is preferably 5mm or less, more preferably 4mm or less, and still more preferably 3mm or less. The thickness T of the wiping sheet 10 is preferably 0.8mm or more and 3mm or less under a load of 370Pa, more preferably 0.9mm or more and 2.8mm or less, and still more preferably 1mm or more and 2.5mm or less. By setting the thickness T of the wiping sheet 10 within this range, the wiping sheet 10 has sufficient rigidity and strength, and the operability during wiping becomes good.

In the present invention, it is particularly preferable that the fibers having different fiber diameters are interlaced without being thermally fused to each other. In this way, the voids between the fibers are increased compared to the case of thermal fusion. As a result, when the wiping solution is carried on the wiping sheet 10, the amount of the wiping solution carried increases.

The wet-type wiping sheet 10 wipes the wiping target surface 1 time by 1 wiping, and the amount of the wiping solution released from the wiping surface to the wiping target surface is preferably 0.5 g/so as to be amiza, more preferably 0.7 g/so as to be amiza, and further preferably 1.0 g/so as to be amiza. The upper limit of the amount released is actually 8 g/tatza or less, preferably 7 g/tatza or less, and more preferably 6 g/tatza or less. If the amount of the release is too small, the wiping cannot be performed sufficiently, and if the amount is too large, wiping liquid tends to remain on the wiping surface. Here, the tatamiza was 1820mm × 910mm, and the area was 1.6552m²。

The release behavior was measured under the condition that the wiping load (load W) was 0.16kN/m²And a wiping speed (speed V) of 1 m/s. When the wiping sheet of the present invention carries the wiping solution, the amount of the released tatamiza per se is within the above range when measured under such measurement conditions.

The maximum amount of liquid that can be carried by the wiping liquid on the wiping sheet 10, i.e., the initial amount of liquid carried, is preferably 1 g/sheet or more, more preferably 10 g/sheet or more, and still more preferably 12 g/sheet or more, when the size of 1 wiping sheet 10 is 285mm × 205mm, as described in the examples below. The upper limit of the initial liquid supporting amount is actually 40 g/sheet or less, preferably 30 g/sheet or less, and more preferably 20 g/sheet or less.

In this way, a liquid release of 1 g/more of the tatamiza per wipe is possible and can be continued to the 6 th more of the tatamiza.

The wiping liquid used for the wiping sheet 10 is generally the same as the user in a wet wiping sheet. That is, the wiping solution may be water alone or an aqueous solution containing a surfactant, and preferably an aqueous solution containing a surfactant.

The surfactant may be any of a nonionic surfactant, an amphoteric surfactant, a cationic surfactant, and an anionic surfactant. For example, an anionic surfactant such as alkylbenzenesulfonic acid or a nonionic surfactant such as polyoxyethylene alkyl ether can be used.

The wiping solution may also contain additives. Examples of the additive include polymers of acrylic acid, methacrylic acid, or maleic acid, or salts thereof, and copolymers of maleic acid and other vinyl monomers, or salts thereof, for the purpose of improving the flushing effect. Examples of the solvent include water-soluble organic solvents such as bactericides, perfumes, fragrances, deodorants, abrasive particles, pH adjusters and alcohols.

The surfactant and additives as described above are typically present in the range used in wet wipe sheets.

Next, a preferred method for producing the wiping sheet 10 shown in fig. 1 will be described with reference to fig. 2 to 8. Fig. 2 shows a manufacturing apparatus 1 suitably used for manufacturing the wiping sheet 10. The production apparatus 1 includes a web forming section 2, a weaving section 3, an electrospinning section 4, and a projection forming section 5.

The web forming section 2 is a member forming a web of the 1 st fibers 20. The web forming section 2 includes a carding machine 21 that forms a web with the 1 st fibers 20 as a raw material of the wiping sheet 10.

The interlaced part 3 is a member that interlaces the 1 st fiber 20 web with water flow. The interlaced part 3 includes a 1 st water flow nozzle 31 for blowing water flow to the 1 st fiber 20 web and a 1 st support belt 32 including an endless belt. The 1 st water jet nozzle 31 is positioned above the 1 st fiber 20 web and the 1 st support belt 32, and can blow a high-pressure water jet over the entire width of the 1 st fiber 20 web. The 1 st support belt 32 is disposed to face the 1 st water jet nozzle 31, and has a structure (not shown) in which water to be blown passes through the belt, and the belt has a lattice-like pattern or a perforated structure. The interlaced body of the 1 st fibers 20 interlaced by the water jet from the 1 st water jet nozzle 31 is conveyed to the electrospinning part 4 by the 1 st support belt 32.

The electrospinning unit 4 generates the 2 nd fiber 40 including the nanofibers by the electrospinning method, and deposits the 2 nd fiber on one surface of the interlaced body of the 1 st fiber 20 interlaced by the water flow nozzle 31 of the interlacing unit 3. The electrospinning unit 4 includes a spraying unit 41 for spraying the starting material liquid for the 2 nd fiber 40 and electrospinning the starting material liquid, and a capturing electrode 42 for capturing the sprayed starting material liquid as the 2 nd fiber 40. The spraying section 41 is constituted by a supply section for the raw material liquid of the 2 nd fiber 40, an electrode, a voltage applying section, and the like (not shown). A positive voltage or a negative voltage is applied to the ejection section 41. The trap electrode 42 is disposed to face the ejection portion 41. The capture electrode 42 includes a conductive member and is grounded.

When a voltage is applied to the ejection part 41, the raw material liquid of the 2 nd fibers 40 is charged by electrostatic induction until being ejected from the ejection part 41, and is ejected in a charged state. The raw material liquid ejected in the charged state causes self-repulsion of the raw material liquid by the action of an electric field, and the 2 nd fibers 40 are produced as nano-sized fine fibers (nanofibers). The generated 2 nd fibers 40 are randomly stacked on one surface of the interlaced body of the 1 st fibers 20 traveling in the vicinity of the capturing electrode 42, and become a fiber aggregate. By this electrospinning step, a laminate 50 including a fiber assembly of the 1 st fibers 20 and the 2 nd fibers 40 is formed. The obtained laminate 50 is conveyed to the convex portion forming section 5.

As the raw material liquid of the 2 nd fiber 40 in the electrospinning method, a liquid in which a polymer compound constituting the 2 nd fiber 40 is dissolved or dispersed in a solvent, or a melt in which a polymer compound is melted can be used. A method using a liquid obtained by dissolving or dispersing a polymer compound in a solvent may be referred to as a solution electrospinning method, and a method using a melt obtained by melting a polymer compound may be referred to as a melt electrospinning method. In the present invention, any electrospinning method can be used.

In the convex portion forming portion 5, a water flow is blown to the stacked body 50 of the fiber aggregate of the 1 st fibers 20 and the fiber aggregate of the 2 nd fibers 40, and the 1 st fibers and the 2 nd fibers are interlaced to form convex portions. The projection forming section 5 includes a 2 nd water flow nozzle 51 for blowing a water flow to the 1 st fiber 20 side of the laminate 50, a projection forming member 52 for forming projections on the 2 nd fiber 40 side by the water flow, a 2 nd support belt 53 provided below the projection forming member 52, and a conveying belt 54 for conveying the laminate 50 having the projections formed thereon to a downstream manufacturing process.

As shown in fig. 2, the 2 nd water flow nozzle 51 is positioned on the 1 st fiber 20 side of the laminate 50, and can blow water flow over the entire width direction area of the laminate 50. The projection forming member 52 is located below the laminate 50 and is disposed so as to face the fiber aggregate of the 2 nd fiber. As shown in fig. 3, the projection forming member 52 has a plurality of circular opening portions 52a regularly formed over the entire area thereof. The projection forming member 52 is not particularly limited as long as it has an opening portion, and a perforated metal, a plastic net, or the like can be used. The shape of the opening portion 52a is also not particularly limited, and may be an ellipse, or a polygon such as a triangle, a quadrangle, or a pentagon, in addition to the circle shown in fig. 3. The convex portion forming member 52 may be integrated with the 2 nd support tape 53 by sewing, bonding, or the like.

As shown in fig. 2 and 4, the water stream blown from the 2 nd water stream nozzle 51 toward the 1 st fiber 20 side surface 50X presses the 2 nd fiber 40 side surface 50Y of the laminate 50 in close contact with the upper surface of the convex portion forming member 52. At the same time, the fiber aggregate of the 1 st fiber 20 and the 2 nd fiber 40 positioned in the opening part 52a is protruded into the opening part 52a to form a plurality of convex parts 50A. At this time, classification of the 1 st fibers 20 and the 2 nd fibers 40 occurs, and in the top portion 50T of the projection 50A, the presence ratio of the 1 st fibers 20 in the top portion 50T is higher than the presence ratio of the 2 nd fibers 40 with respect to the entire fibers constituting the projection 50A. At the same time, in the bottom portion 50B of the projection 50A, the presence ratio of the 2 nd fibers 40 in the bottom portion 50B is higher than the presence ratio of the 1 st fibers 20 with respect to the entire fibers constituting the projection 50A. Through these steps, the laminate 50 having the plurality of projections 50A formed thereon can be obtained.

As shown in FIG. 5, the width L of the opening portion 52a of the projection-forming member 52 is preferably 400 μm or more and 10 mm. By providing the width L, the stacked body 50 can be formed into the convex portion 50A having a good appearance and capable of reducing the resistance at the time of wiping.

As shown in fig. 5, the thickness T of the projection-forming member 52 is preferably 800 μm or more and 3mm or less, and more preferably 900 μm or more and 2mm or less. By having a thickness in this range, a favorable projection 50A can be formed in the laminate 50.

As another embodiment of the projection forming part 5 (hereinafter, referred to as embodiment 2), as shown in fig. 6 and 7, two kinds of

projections

50A and 2 nd projection 520A (hereinafter, projection 50A is also referred to as projection 1 in embodiment 2) may be formed on the laminate 50 by using the 2 nd projection forming member 520 in addition to the projection forming member 52. In embodiment 2, as shown in fig. 6, the 2 nd projection forming member 520 is disposed so as to overlap with the upper portion of the projection forming member 52. The 2 nd projection forming member 520 has a plurality of square opening portions 520a regularly formed over the entire surface thereof. As shown in fig. 8, the width La of the square opening portion 520a becomes larger than the width L of the opening portion 52a of the convex portion forming member 52. By using the two kinds of

projection forming members

52 and 520 in a superposed manner, the 1 st projection 50A can be formed in a shape that is raised from the top of the 2 nd projection 520A, for example, on the 1 st surface 50Y side of the wiping sheet 10 (hereinafter, also referred to as wiping sheet 10' in embodiment 2) in a plurality of and regularly arranged.

According to the 2 nd embodiment in which the two kinds of

projection forming members

52 and 520 are used in a superposed manner, the 1 st projection 50A and the 2 nd projection 520A including a macroscopic pattern (a rhombic lattice pattern in the 2 nd embodiment) larger than the 1 st projection 50A are provided on the 1 st surface 50Y side of the wiping sheet 10', and the 1 st projection 50A is located in the 2 nd projection 520A to form a two-step level difference. In this case, at the top of the 1 st projection 50A, the presence ratio of the 1 st fibers 20 in the top is higher than the presence ratio of the 2 nd fibers 40 with respect to the entire fibers constituting the 1 st projection 50A, and at the bottom of the 1 st projection 50A, the presence ratio of the 2 nd fibers 40 in the bottom is higher than the presence ratio of the 1 st fibers 20 with respect to the entire fibers constituting the 1 st projection 50A.

In embodiment 2 in which two types of projection-forming

members

52 and 520 are used in a superimposed manner, as shown in fig. 7, the laminated body 50 is pressed so that the surface 50Y on the 2 nd fiber 40 side comes into close contact with the 2 nd projection-forming member 520 by the water flow blown from the 2 nd water flow nozzle 51 toward the surface 50X on the 1 st fiber 20 side. At this time, the 1 st fibers 20 and the 2 nd fibers 40 enter the opening part 520A, and a plurality of 2 nd convex parts 520A having a shape corresponding to the shape of the opening part of the 2 nd convex part forming member 520 are regularly formed. Further, by the water flow blown from the 2 nd water flow nozzle 51, the 2 nd convex portions 520A are pressed so that the 2 nd fiber 40 side surface 50Y comes into close contact with the convex portion forming member 52, and the 1 st convex portions 50A are formed on the top portions of the 2 nd convex portions 520A in a plurality of regularly arranged states. In this way, the 1 st projection 50A is formed in a plurality of projections rising from the top of one 2 nd projection 520A, and thus the 1 st projection 50A and the 2 nd projection 520A have a shape having two levels of height difference. Through this step, a laminate 50 having a plurality of projections 50A formed thereon can be obtained, as in the case of the embodiment in which the projection-forming member 52 is used alone.

The wiping sheet 10' of embodiment 2 obtained by the above-described steps protrudes from the 1 st fiber 20 side surface (2 nd surface) 50X toward the 2 nd fiber side surface (1 st surface) 50Y to form the 1 st convex portion 50A and the 2 nd convex portion 520A. The 1 st projection 50A and the 2 nd projection 520A are raised from the flat surface of the 1 st surface 50Y. As described above, the 1 st projection 50A is located inside the 2 nd projection 520A, and has a shape rising from the top of the 2 nd projection 520A. By having these shapes, a convex portion having a two-step difference in height is formed when viewed from the flat surface of the 1 st surface 50Y. The 2 nd surface 50X may be a flat surface over the entire area thereof by the method of manufacturing the wiping sheet 10' according to embodiment 2, and the areas corresponding to the 1 st convex portions 50A and the 2 nd convex portions 520A may be recessed.

As shown in fig. 8, the width La of the opening 520a of the 2 nd projection forming member 520 is preferably 400 μm or more and 10mm or less, and more preferably 420 μm or more and 8mm or less. By providing the width La, the 2 nd convex portion 520A having a good appearance and a reduced resistance at the time of wiping can be formed in the laminated body 50.

As shown in FIG. 8, the thickness Ta of the 2 nd projection forming member 520 is preferably 600 μm or more and 4mm or less, and more preferably 700 μm or more and 3mm or less. By having a thickness in this range, the 2 nd convex part 520A having a good appearance and capable of reducing the resistance at the time of wiping can be formed in the laminated body 50.

Returning again to fig. 2, finally, the laminate 50 having the convex portions 50A formed by the convex portion forming portion 5 is conveyed downstream from the convex portion forming portion 5 by the conveyor belt 54, and the target dry wiping sheet 10 (or wiping sheet 10') is obtained. Further, after the laminate 50 having the convex portions 50A formed by the convex portion forming portion 5 is conveyed downstream from the convex portion forming portion 5 by the conveyor belt 54, the wiping liquid may be further supplied from the surface side corresponding to the 2 nd surface of the wiping sheet 10 and carried. Through this process, the target wet-type wiping sheet 10 (or wiping sheet 10') can be obtained.

The amount of wiping liquid to be carried when producing the wet-type wiping sheet 10 (or wiping sheet 10') is preferably 6 g/sheet or more, more preferably 8 g/sheet or more, and still more preferably 10 g/sheet or more, when it is 285mm × 205mm, as described in the example of the size of 1 wiping sheet explained below. The upper limit of the content of the wiping solution is preferably 40 g/sheet or less, more preferably 30 g/sheet or less, and further preferably 20 g/sheet or less. The wiping solution can be carried by spraying, coating, dipping, or the like.

The wiping sheet 10 (or wiping sheet 10') produced in this manner can be used alone or attached to a cleaning tool such as a wiper, and is used for wiping floors, walls, and other buildings, building materials such as cabinets, window glasses, mirrors, doors, and door handles, furniture such as carpets, tables, kitchens, bathrooms, bodies, sanitary goods, packaging, and the like.

The present invention has been described above based on preferred embodiments thereof, but the present invention is not limited to the above embodiments. For example, in fig. 2, the number of the 1 st and 2 nd

water flow nozzles

31 and 51, the water pressure, and the like may be the same or different.

The wiping sheet 10 (or wiping sheet 10') of the above embodiment is a wiping sheet containing two types of fibers of the 1 st and 2 nd fibers, and may be a wiping sheet containing three or more types of fibers instead.

The present invention further discloses the following wiping sheet and a method for manufacturing the same in relation to the above embodiment.

＜1＞

A wiping sheet comprising a fiber assembly comprising at least 1 st fibers and 2 nd fibers having a smaller diameter than the 1 st fibers, the fibers being entangled, the wiping sheet having a 1 st surface serving as a wiping surface and a 2 nd surface located on the opposite side of the 1 st surface; and is

The 2 nd fiber exists in the 1 st surface at a higher ratio than in the 2 nd surface;

a plurality of convex portions are formed on the 1 st surface side;

the presence ratio of the 1 st fibers in the top portion is higher than the presence ratio of the 2 nd fibers with respect to the entire fibers constituting the convex portion;

the presence ratio of the 2 nd fibers in the bottom portion is higher than the presence ratio of the 1 st fibers with respect to the entire fibers constituting the convex portion.

＜2＞

A wiping sheet as described above in the above < 1 > wherein the 1 st fibers and the 2 nd fibers are interlaced with each other without being heat-fused.

＜3＞

The above-mentioned wiping sheet having < 1 > or < 2 > is preferably such that the area ratio of the 2 nd fibers in the 1 st surface is 40% or more and 99% or less, more preferably 45% or more and 95% or less, further preferably 50% or more and 90% or less, and the area ratio of the 2 nd fibers in the 2 nd surface is preferably 0% or more and 55% or less.

＜4＞

A wiping sheet according to any one of the above-mentioned items < 1 > to < 3 > in which a plurality of the above-mentioned projections are regularly arranged.

＜5＞

The wiping sheet according to any one of the above-mentioned < 1 > to < 4 >, wherein the region corresponding to the convex portion on the 2 nd surface side is recessed from the flat surface of the 2 nd surface toward the 1 st surface to form a concave portion.

＜6＞

A wiping sheet as described in any of the above items < 1 > to < 4 >, wherein the entire area of the 2 nd surface is a flat surface.

＜7＞

A wiping sheet as described in any of the above items < 1 > to < 6 >, wherein the protrusions are solid portions whose interiors are filled with fibers.

＜8＞

A wiping sheet as described in any of the above items < 1 > to < 6 >, wherein the protrusions are solid portions whose interiors are filled with the 1 st fibers and/or the 2 nd fibers.

＜9＞

The wiping sheet according to any of the above-mentioned < 1 > to < 8 >, wherein the convex portions are regularly arranged on the 1 st surface side of the wiping sheet.

＜10＞

The wiping sheet according to any one of the above-mentioned items < 1 > to < 9 >, wherein the projections are regularly arranged along the longitudinal direction and/or along the width direction of the wiping sheet.

＜11＞

The wiping sheet according to any one of the above-mentioned < 1 > to < 10 >, wherein the width of the projection is 400 μm or more and 10mm or less, and the height is 110 μm or more and 25mm or less.

＜12＞

The wiping sheet of any of the above-mentioned < 1 > to < 11 >, wherein the width of the convex portion is further preferably 800 μm or more, more preferably 900 μm or more, and the width W is further preferably 8mm or less, more preferably 5mm or less.

＜13＞

A wiping sheet as described in any of the above < 1 > to < 12 > having the convex portion and a 2 nd convex portion including a macroscopic pattern larger than the convex portion on the 1 st surface side, the convex portion being located in the 2 nd convex portion to form a two-step level difference;

at the top of the convex portion, the ratio of the 1 st fibers present in the top portion is higher than the ratio of the 2 nd fibers present in the entire fibers constituting the convex portion, and at the bottom of the convex portion, the ratio of the 2 nd fibers present in the bottom portion is higher than the ratio of the 1 st fibers present in the entire fibers constituting the convex portion.

＜14＞

The wiping sheet of < 13 > above, wherein the convex portions are formed on the top of the 2 nd convex portion larger than the convex portions.

＜15＞

The wiping sheet of < 13 > above, wherein a plurality of the above-mentioned projections are formed on the top of the 2 nd projection.

＜16＞

As described above < 1 > toThe wiping sheet of any of < 15 > wherein the frictional force between the surface to be wiped and the wiping sheet is preferably 55N/m to a wiping sheet of 10cm by 25cm size²The resistance at the time of wiping with the pressure of (3) is 10N or less, more preferably 5N or less, and still more preferably 4N or less.

＜17＞

The wiping sheet according to any one of the above-mentioned items < 1 > to < 16 >, wherein the ratio of the 1 st fibers and the 2 nd fibers present at the top of the protrusions is 3 times or more the number of the 1 st fibers as compared with the number of the 2 nd fibers in the entire fibers constituting the protrusions.

＜18＞

The wiping sheet according to any one of the above-mentioned items < 1 > to < 17 >, wherein the ratio of the 1 st fibers and the 2 nd fibers present in the bottom of the protrusions is 2 times or more the number of the 2 nd fibers as compared with the number of the 1 st fibers in the entire fibers constituting the protrusions.

＜19＞

The wiping sheet according to any one of the above-mentioned items < 1 > to < 18 >, wherein the 1 st and 2 nd fibers are polyester, polyamide, polyolefin, cellulose fiber, or fibers made of various metals, glasses, or minerals, preferably polyester, polyamide, polyolefin, or cellulose fiber.

＜20＞

A wiping sheet as defined in any of the above items < 1 > to < 19 >, wherein the 1 st and 2 nd fibers are preferably fibers of the same composition.

＜21＞

A wiping sheet as described in any of the above < 1 > to < 20 >, wherein the diameter of the 1 st fiber is preferably 10 μm or more and 30 μm or less, more preferably 15 μm or more and 25 μm or less.

＜22＞

A wiping sheet as described in any of the above < 1 > to < 21 >, wherein the diameter of the 2 nd fibers is preferably 0.1 μm or more and 9 μm or less, more preferably 0.5 μm or more and 5 μm or less.

＜23＞

The wiping sheet according to any one of the above-mentioned < 1 > to < 22 >, wherein the wiping liquid is carried on at least the fiber aggregate positioned on the 2 nd surface side.

＜24＞

The wiping sheet of < 23 > has a release layer for the wiping solution and a liquid retaining layer for supporting the wiping solution, wherein the release layer includes the 1 st surface.

＜25＞

The wiping sheet according to any one of the above-mentioned < 1 > to < 24 >, wherein, when a virtual circle having a diameter of 20mm is drawn at an arbitrary position on the 1 st surface, the number of the convex portions present in the virtual circle is 10 or more and 60 or less.

＜26＞

The wiping sheet as described in any of the above-mentioned < 1 > to < 25 >, wherein the wiping surface side is 1g/m with respect to the basis weight of the fibers constituting the wiping sheet²Above and 100g/m²The following.

＜27＞

A wiping sheet as defined in any of the above-mentioned < 1 > to < 26 >, wherein the thickness of the wiping sheet is 1mm or more and 5mm or less under a load of 40 Pa.

＜28＞

A method for producing a wiping sheet, which is a method for producing a wiping sheet as defined in any one of the above-mentioned < 1 > to < 27 >;

in a state that a laminated body of a fiber assembly of a 1 st fiber and a fiber assembly of a 2 nd fiber having a diameter smaller than that of the 1 st fiber is arranged in such a manner that the fiber assembly of the 2 nd fiber faces a convex part forming member having a plurality of open hole parts, a water flow is blown from the fiber assembly side of the 1 st fiber to interlace the 1 st fiber and the 2 nd fiber and to cause the fiber assembly positioned in the open hole parts to protrude into the open hole parts.

＜29＞

A method for producing a wiping sheet having the above-mentioned < 28 > wherein a fiber aggregate of the 2 nd fibers is formed by a melt electrospinning method.

Examples

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 this embodiment.

[ example 1]

The wiping sheet 10 having the structure shown in fig. 1 was manufactured using the manufacturing apparatus 1 and the convex portion forming member 52 shown in fig. 2 to 5. As the 1 st fibers 20, those containing PET in mass ratio: acrylic acid: rayon 7: 1.5: 1.5A concrete body having an average diameter of 11.4. mu.m. As the 2 nd fibers 40, polypropylene having an average diameter of 1 μm obtained by an electrospinning method was used. The weight per unit area of the 1 st fiber 20 was set to 60g/m²The weight per unit area of the 2 nd fibers 40 was set to 5g/m². The wiping sheet 10 was rectangular and had dimensions 285mm × 205mm and a thickness T of 1.6 mm. The height H of the convex portion 50A on the 1 st surface 50Y side of the wiping sheet 10 was 0.7mm, and the width W was 2 mm. The projections 50A are arranged in 34 pieces on average in an imaginary circle having a diameter of 20 mm. The area ratio of the 2 nd fibers 40 in the 1 st plane 50Y is 90%, and the area ratio of the 2 nd fibers 40 in the 2 nd plane 50X is 5%. The ratio of the 1 st fibers 20 present in the top portion 50T to the 2 nd fibers 40 is 2 times (67% by area ratio) on an area basis with respect to the entire fibers constituting the projection 50A, and the ratio of the 2 nd fibers 40 present in the bottom portion 50B to the 1 st fibers 20 is 1.1 times (52% by area ratio) on an area basis with respect to the entire fibers constituting the projection 50A.

The wiping sheet 10 of example 1 is a wet wiping sheet carrying wiping liquid. The wiping liquid is carried on at least the fiber assembly positioned on the 2 nd surface side. The amount of the wiping solution was 20 g/sheet. An aqueous solution of a surfactant (EMULGEN108, manufactured by kaowski) at 0.01 mass% was used as the wiping solution.

[ example 2]

A wiping sheet was produced in the same manner as in example 1, except that the wiping sheet of example 1 did not carry the wiping solution. That is, the wiping sheet of example 2 was a dry wiping sheet.

Comparative example 1

As the wet wiping sheet, a wet sheet for a Scotch Brite (registered trademark) floor manufactured by 3M company was used. The wet-type wiping sheet contains a fiber aggregate of small-diameter fibers and large-diameter fibers, but the projections of the present invention are not formed on the wiping surface.

Comparative example 2

As a dry wiping sheet, a wet sheet for Scotch Brite (registered trademark) flooring manufactured by 3M corporation was used by drying at 20 ℃ under an environment of 65% relative humidity for 24 hours. The wiping sheet contains a fiber aggregate of small-diameter fibers and large-diameter fibers, but the convex portions of the present invention are not formed on the wiping surface.

Comparative example 3

As the dry wiping sheet, an ultra-fine absorbent dry sheet manufactured by yazaki industries, inc. The wiping sheet contains a fiber aggregate of small-diameter fibers and large-diameter fibers, but the convex portions of the present invention are not formed on the wiping surface.

[ evaluation ]

55N/m was applied to the wiping sheets of the examples and comparative examples²The floor (Conbit new advance101, manufactured by WOODONE corporation) was set to a surface to be wiped, and the pressure of (1.8 m)²The area of (2) was wiped, and the resistance at that time was measured by the above-mentioned method. The results are shown in fig. 9 and 10.

As a result of comparing the resistances in example 1 and comparative example 1 as wet-type wiping sheets, the resistance in example 1 was 2.7N as shown in fig. 9. On the other hand, the resistance of comparative example 1 was 15.7N. From these results, it is clear that the wet-type wiping sheet 10 of example 1 has a low frictional resistance during wiping and a high workability.

As a result of comparing the resistances in example 2 and comparative examples 2 and 3 as dry wiping sheets, the resistance of example 2 was 1.8N as shown in fig. 10. On the other hand, the resistance of comparative example 2 was 2.2N, and the resistance of comparative example 3 was 4.1N. From these results, it is understood that the dry wiping sheet 10 of example 2 has less frictional resistance during wiping and higher workability, as the wet wiping sheet 10 of example 1.

As is clear from comparison between example 1 and comparative example 1, and example 2 and comparative example 2, in particular, it is clear that the friction resistance is remarkably reduced when the wiping sheet of the present invention is used in a wet state.

Industrial applicability

According to the present invention, a wiping sheet which reduces frictional resistance during wiping and improves operability during wiping, and a method for producing the same are provided.

Claims

1. A wiping sheet comprising a fiber assembly comprising at least 1 st fibers and 2 nd fibers having a smaller diameter than the 1 st fibers and interwoven with these fibers, the wiping sheet having a 1 st surface serving as a wiping surface and a 2 nd surface located on the opposite side of the 1 st surface,

the 2 nd fibers are present at a higher ratio on the 1 st side than on the 2 nd side,

a plurality of convex parts are formed on the 1 st surface side,

the ratio of the 1 st fibers present in the top portion is higher than the ratio of the 2 nd fibers present in the entire fibers constituting the projection,

2. The wiping sheet according to claim 1, wherein the 1 st fibers and the 2 nd fibers are interwoven with each other without being thermally fused.

3. The wiping sheet according to claim 1 or 2, wherein the area ratio of the 2 nd fibers in the 1 st surface is 40% or more and 99% or less,

and the area ratio of the 2 nd fibers in the 2 nd surface is 0% to 55%.

4. The wiping sheet according to claim 1 or 2, which is regularly provided with a plurality of the convex portions.

5. The wiping sheet according to claim 1 or 2, wherein a region corresponding to the convex portion on the 2 nd surface side is formed with a concave portion that is concave from the flat surface of the 2 nd surface toward the 1 st surface.

6. The wiping sheet according to claim 1 or 2, wherein the entire area of the 2 nd face becomes a flat face.

7. The wiping sheet according to claim 1 or 2, wherein the convex portion is a solid portion whose inside is filled with fibers.

8. The wiping sheet according to claim 1 or 2, wherein the convex portion is a solid portion whose inside is filled with the 1 st fiber and the 2 nd fiber.

9. The wiping sheet according to claim 1 or 2, wherein the convex portions are regularly arranged along a longitudinal direction and/or along a width direction of the wiping sheet.

10. The wiping sheet according to claim 1 or 2, wherein the projections have a width of 400 μm or more and 10mm or less and a height of 110 μm or more and 25mm or less.

11. The wiping sheet according to claim 1 or 2, wherein the width of the projections is 800 μm or more and 8mm or less.

12. The wiping sheet according to claim 1 or 2, which has the convex portion and a 2 nd convex portion including a macroscopic pattern larger than the convex portion on the 1 st surface side, and the convex portion is located in the 2 nd convex portion to form a two-step level difference,

at the top of the convex portion, the ratio of the 1 st fibers to the total fibers constituting the convex portion is higher than the ratio of the 2 nd fibers,

and at the bottom of the convex portion, the existence ratio of the 2 nd fiber in the bottom is higher than the existence ratio of the 1 st fiber with respect to the whole fiber constituting the convex portion.

13. The wiping sheet according to claim 12, wherein the convex portion is formed at the top of the 2 nd convex portion larger than the convex portion.

14. The wiping sheet according to claim 12, wherein a plurality of the projections are formed on the top of the 2 nd projection.

15. The wiping sheet according to claim 1 or 2, wherein 55N/m is applied to a wiping sheet of 10cm x 25cm size²The resistance to wiping of the surface to be wiped is 10N or less.

16. The wiping sheet according to claim 1 or 2, wherein the 1 st fibers and the 2 nd fibers in the top portions of the protrusions are present in a ratio of 3 or more times as many as the 2 nd fibers on a number basis relative to the entire fibers constituting the protrusions.

17. The wiping sheet according to claim 1 or 2, wherein the ratio of the 1 st fibers and the 2 nd fibers present in the bottom of the convex portion is 2 times or more the number of the 2 nd fibers as compared with the number of the 1 st fibers in the entire fibers constituting the convex portion.

18. The wiping sheet according to claim 1 or 2, wherein the 1 st and 2 nd fibers are each independently a polyester, a polyamide, a polyolefin, a cellulose fiber, a fiber made of various metals, glasses, or minerals.

19. The wiping sheet according to claim 1 or 2, wherein the 1 st fiber and the 2 nd fiber are fibers of the same composition.

20. The wiping sheet according to claim 1 or 2, wherein the diameter of the 1 st fiber is 10 μm or more and 30 μm or less.

21. The wiping sheet according to claim 1 or 2, wherein the diameter of the 2 nd fiber is 0.1 μm or more and 9 μm or less.

22. The wiping sheet according to claim 1 or 2, wherein the wiping liquid is carried on at least the fiber aggregate positioned on the 2 nd surface side.

23. The wiping sheet according to claim 22, which has a release layer for the wiping solution and a liquid retaining layer for supporting the wiping solution, the release layer comprising the 1 st surface.

24. The wiping sheet according to claim 1 or 2, wherein when a virtual circle having a diameter of 20mm is drawn at an arbitrary position on the 1 st surface, the number of the convex portions present in the virtual circle is 10 or more and 60 or less.

25. The wiping sheet according to claim 1 or 2, wherein the wiping surface side is 1g/m in terms of the weight per unit area of the fibers constituting the wiping sheet²Above and 100g/m²The following.

26. The wiping sheet according to claim 1 or 2, wherein the thickness of the wiping sheet is 1mm or more and 5mm or less under a load of 40 Pa.

27. A method for producing a wiping sheet according to any one of claims 1 to 26,

28. The method for producing a wiping sheet according to claim 27, wherein the fiber aggregate of the 2 nd fibers is formed by a melt electrospinning method.