WO2018105340A1

WO2018105340A1 - Wet wiping sheet

Info

Publication number: WO2018105340A1
Application number: PCT/JP2017/041116
Authority: WO
Inventors: 行人成田; 翔太郎百合野; 金田　学; 斉藤　公二; 東城　武彦
Original assignee: 花王株式会社
Priority date: 2016-12-05
Filing date: 2017-11-15
Publication date: 2018-06-14
Also published as: TWI748015B; TW201833403A; MY195844A

Abstract

Provided is a wet wiping sheet which has a first surface and a second surface on the side opposite to the first surface and which comprises a fiber aggregate consisting of at least two types of fibers having different fiber diameters, wherein: the at least two types of fibers having different fiber diameters are interlaced with each other; of the fibers in the fiber aggregate, the proportion of the fibers having a smaller fiber diameter is greater on the first surface side than the second surface side; of the fibers in the fiber aggregate, the proportion of the fibers having a larger fiber diameter is greater on the second surface side than the first surface side; the first surface side has a capillarity pressure higher than the second surface side; and a wiping liquid is carried at least in the fiber aggregate on the second surface side.

Description

Wet wiping sheet

The present invention relates to a wet wiping sheet.

Conventionally, wet wiping sheets such as cleaning wipers and sanitary products are products that are used on a daily basis, and the required performance has been increased, and energetically studied, and performance has been improved steadily. For example, in order to improve wiping performance, friction resistance, and heat resistance, it has been proposed to fibrillate so that the liquid crystal polyester contains 50% by mass or more and the fiber diameter of the surface layer portion is 0.5 μm or less (Patent Document 1). reference). Moreover, in the 1st layer nearest to an absorber, when a fiber density is high and a large amount of liquid is discharged | emitted by the surface sheet, it becomes difficult to transfer a liquid to an absorber. Therefore, it has been proposed to use a non-woven fabric having low diffusibility when the liquid permeates without obstructing the liquid transfer from the top sheet to the absorber (see Patent Document 2).

JP 2013-159877 A JP 2008-144322 A

The present invention is a wet wiping sheet having a first surface and a second surface opposite to the first surface, wherein the wet wiping sheet is made of a fiber assembly of at least two types of fibers having different fiber diameters. Fibers of different fiber diameters are entangled, and among the fibers of the fiber assembly, the proportion of fibers having a thin fiber diameter is greater on the first surface side than on the second surface side, and the fibers of the fiber assembly Among them, the proportion of fibers having a large fiber diameter is higher on the second surface side than on the first surface side, the capillary pressure on the first surface side is higher than that on the second surface side, and the wiping liquid is at least It is a wet wiping sheet carried on the fiber assembly on the second surface side.

The above and other features and advantages of the present invention will become more apparent from the following description with reference to the accompanying drawings as appropriate.

It is a drawing substitute photograph which imaged the 1st surface of the wet wiping sheet | seat surfaces of this invention using the scanning electron microscope. It is a drawing substitute photograph which imaged the 2nd surface of the wet wiping sheet | seat surfaces of this invention using the scanning electron microscope. It is a drawing substitute photograph which imaged a part of section of a wet wiping sheet of the present invention using a scanning electron microscope. It is a drawing substitute photograph which imaged another part of the cross section of the wet wiping sheet of this invention using the scanning electron micrograph. It is the drawing substitute photograph which imaged a part of cross section of the typical wet wiping sheet | seat of this invention manufactured using the scanning electron microscope. It is the graph which measured and measured the liquid discharge | emission amount (g) per 1 tatami and the wiping area (tatami) with the typical wet wiping sheet | seat of this invention manufactured. 3 is a drawing-substituting photograph showing a first surface of a typical wet wiping sheet of the present invention produced.

The present inventors examined the prior art including the above proposal. In the conventional wet wiping sheet containing the wiping liquid, the wiping liquid is discharged to the wiping surface more than the amount necessary for wiping the dirt on the wiping surface in one wiping of the dirt (one wiping). For this reason, it turned out that there is room for further improvement. In particular, in order to remove the dirt, it becomes a problem when the dirt is not removed unless it is rubbed strongly. That is, the wiping liquid is discharged to the wiping target surface more than necessary to wipe off the dirt on the wiping target surface. Therefore, in the case of wiping with a large wiping area such as rugs, carpets, and floors, the wiping is often replaced with a new wet wiping sheet.

Therefore, the present invention relates to a wet wiping sheet that can be wiped lightly to remove dirt and does not need to be replaced even when the wiping area is large or the number of times of replacement is small.

The inventors of the present invention have studied various means for preventing the wiping liquid from being released to the surface to be wiped more than the amount necessary for wiping off the dirt on the surface to be wiped, particularly when rubbed strongly. As a result, as described above, by using at least two kinds of fibers having different fiber diameters and controlling the existence state of the fibers having a small fiber diameter and the capillary pressure, the present inventors have found that the above problems can be solved, and have reached the present invention. . The wiping in the present invention includes both the meanings of cleaning and wiping, and generally means wiping. For example, it shall include cleaning of buildings such as floors, walls, ceilings, pillars, etc., cleaning of fittings and fixtures, wiping of articles, wiping of the body and instruments related to the body, and the like.

According to the present invention, it is possible to provide a wet wiping sheet which can be wiped lightly to remove dirt and which is not exchanged even when the wiping area is large or the exchange frequency is small.
Hereinafter, the wet wiping sheet of the present invention and the production method thereof will be described based on preferred embodiments thereof.
First, the wet wiping sheet will be described.

<< wet wiping sheet >>
The wet wiping sheet of the present invention has a first surface and a second surface that is the opposite surface of the first surface. That is, of the surfaces forming the front and back of the wet wiping sheet, one surface (for example, the front surface) is the first surface, and the other surface (for example, the back surface) is the second surface. Hereinafter, for example, the first surface will be described as a wiping surface. The wiping surface is a surface that discharges the wiping liquid. The wet wiping sheet is composed of a fiber assembly of at least two kinds of fibers having different fiber diameters, and at least two kinds of fibers having different fiber diameters are entangled. Of the two types of fibers having different fiber diameters (thick fibers and fibers thinner than this), at least the fibers with a small fiber diameter exist on the first surface side and the second surface side. In the fiber assembly, the ratio of the fibers having the thin fiber diameters among the fibers having the two types of fiber diameters is larger on the first surface side than on the second surface side (see FIG. 1). In the fiber assembly, the proportion of fibers having a large fiber diameter is greater on the second surface side than on the first surface side (see FIG. 2). The capillary pressure on the first surface side is higher than that on the second surface side. Further, at least the wiping liquid is carried on the fiber assembly on the second surface side.

In addition, the said fiber assembly is a fiber assembly compounded mainly by the entanglement of the mutual fibers. In addition, carrying at least the wiping liquid on the fiber assembly on the second surface side is an aspect in which the fiber assembly on the second surface side contains the wiping liquid, and the fiber assembly on the first surface side also has a gap in the gap. An embodiment including a wiping liquid is also included. Preferably, the amount of the wiping liquid supported is larger than the amount supported by the fiber aggregate on the first surface side than the amount supported by the fiber aggregate on the first surface side.

First, a scanning electron microscope (SEM) photograph of the wet wiping sheet of the present invention will be described with reference to FIGS.
3 and 4 are photographs obtained by imaging different portions of the cross-section of the wet wiping sheet of the present invention cut by a cutter. In either case, it is shown that a fiber assembly composed of fibers having a small fiber diameter exists on the upper side of the figure, and the upper surface is the first surface (surface). Accordingly, the lower surface in the figure is the second surface (back surface).

As shown in FIG. 1, when the first surface of the wet wiping sheet of the present invention is observed from above with a scanning electron microscope, aggregates composed of fibers having a small fiber diameter and fibers having a large fiber diameter are confirmed. The first surface of the wet wiping sheet has more fibers with a smaller fiber diameter than fibers with a larger fiber diameter. As is clear from FIG. 1, the entire first surface is not a fiber assembly made of fibers having a small fiber diameter, but a fiber assembly made of fibers having a small fiber diameter contains fibers having a large fiber diameter. .
On the other hand, as shown in FIG. 2, when the second surface of the wet wiping sheet of the present invention is observed from above with a scanning electron microscope, an aggregate of fibers having a large fiber diameter and a fiber having a small fiber diameter are confirmed. The second surface of the wet wiping sheet has more fibers having a larger fiber diameter than fibers having a smaller fiber diameter. As is clear from FIG. 2, the entire second surface is not a fiber assembly made of fibers having a large fiber diameter, but includes fibers having a small fiber diameter in a fiber assembly made of fibers having a large fiber diameter. .
In FIGS. 1 and 2, the observation range of the scanning electron microscope is 290 μm × 380 μm, which is enlarged by 330 times. 3 and 4, the observation range of the scanning electron microscope is 170 μm × 240 μm, and is enlarged 500 times.

<Fiber>
The fibers constituting the fiber assembly in the present invention are at least two kinds of fibers having different fiber diameters. Typical examples of the fiber include polyester, polyamide, polyolefin, cellulose fiber, and fibers made from various metals, glass, and minerals. Among these, polyester, polyamide, polyolefin, and cellulose fiber are preferable.

The polyester may be any polyester as long as it has a structure having an ester bond in the polymer main chain. Examples thereof include polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and 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), and polyvinyl chloride.
As described above, the polyolefin may be a homopolymer or a copolymer.

The polyamide may be any polyamide as long as it has a structure having an amide bond in the polymer main chain. For example, polycondensation nylon such as nylon 6, nylon 11 and nylon 12, nylon 66, nylon 610, nylon 612, nylon 6T, nylon 6I, nylon 9T and nylon M5T can be mentioned. Moreover, the polyamide obtained by the following diamine component and dicarboxylic acid component is mentioned.

Examples of the diamine component include tetramethylene diamine, pentamethylene diamine, 2-methylpentane diamine, hexamethylene diamine, heptamethylene diamine, octamethylene diamine, nonamethylene diamine, decamethylene diamine, dodecamethylene diamine, 2,2,4-trimethyl. -Aliphatic diamine compounds such as hexamethylenediamine and 2,4,4-trimethylhexamethylenediamine. 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2,2 Examples include alicyclic diamine compounds such as bis (4-aminocyclohexyl) propane, bis (aminomethyl) decalin, and bis (aminomethyl) tricyclodecane. Furthermore, diamine compounds having an aromatic ring such as metaxylylenediamine, paraxylylenediamine, bis (4-aminophenyl) ether, paraphenylenediamine, bis (aminomethyl) naphthalene, and the like can be given.

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. Moreover, phthalic acid compounds, such as isophthalic acid, terephthalic acid, ortho phthalic acid, are mentioned. Further, 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, And naphthalenedicarboxylic acid compounds such as 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid.

These diamine components and dicarboxylic acid components, including nylons, may be used alone or in combination.

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

Moreover, these mixed fibers, for example, polyethylene / polyethylene terephthalate, polypropylene / polyethylene terephthalate and the like can also be mentioned.

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

The fiber length of the fiber, that is, the average fiber length of the whole fiber used in the present invention is preferably 1 mm or more and 100 mm or less, more preferably 10 mm or more and 90 mm or less, and further preferably 20 mm or more and 60 mm or less.

Among the fiber diameters of fibers having different fiber diameters, the difference between the fiber diameter of the thin fibers and the fiber diameter of the thick fibers is preferably 1 μm or more and 29.9 μm or less from the viewpoint of imparting a difference in capillary pressure described later, and is 2 μm or more. 28 μm or less is more preferable, and 5 μm or more and 27 μm or less is more preferable.
Of the fiber diameters of fibers having different fiber diameters, the fiber diameter of the thin fibers is preferably 0.1 μm or more and 9 μm or less, more preferably 0.3 μm or more and 7 μm or less, and further preferably 0.5 μm or more and 5 μm or less. Among the fiber diameters of fibers having different fiber diameters, the fiber diameter of a thick fiber is preferably 10 μm or more and 30 μm or less, more preferably 11 μm or more and 28 μm or less, and further preferably 15 μm or more and 25 μm or less. A fiber having a small fiber diameter and a fiber having a large fiber diameter are selected in accordance with the wiping function.

The fibers having different fiber diameters may be the same component fibers or different component fibers, but the same component fibers are preferred in the present invention. Also, the fiber lengths may be the same or different, but in the present invention, fibers having the same fiber length are preferred.

In the present invention, at least two types of fibers having different fiber diameters are entangled. The ratio of the presence of fibers having a small fiber diameter is greater on the first surface side than the second surface side, and the ratio of the presence of fibers having a large fiber diameter is greater on the second surface side than the first surface side, and the first surface. The capillary pressure on the side is higher than that on the second surface side. Thereby, even if it wipes strongly at the time of wiping, the quantity of the wiping liquid discharge | released in order to wipe off the stain | pollution | contamination of a wiping object surface can be controlled to required amount. Therefore, even in the case of wiping with a wide wiping area such as rugs, carpets, and floors, it is not necessary to replace with a new wet wiping sheet during the wiping, or the number of replacements can be reduced. The ratio between the “fibers with a small fiber diameter” and the “fibers with a large fiber diameter” may be within a range in which a difference in capillary pressure occurs, and can be set as appropriate depending on the use, use mode, etc. of the wiping sheet. Absent.
<Measurement method of fiber ratio>
The magnification is magnified to 330 times with a scanning electron microscope, the number of fibers having a large fiber diameter and a fiber having a small fiber diameter in the field of view range of 290 μm × 380 μm is measured, and the ratio of each is derived. As described above, a fiber having a fiber diameter of 9 μm or less is defined as a fiber having a thin fiber diameter, and a fiber having a fiber diameter of 10 μm or greater is defined as a fiber having a large fiber diameter. Arbitrary 20 points on the sheet surface are measured in the same manner, and the average value is set as the ratio of the fibers on the first surface and the second surface.

Generally, it is known that the capillary pressure Pc follows the following relational expression.

The capillary pressure Pc derived from the above equation is a value using the summary statistic derived from the measurement of the nonwoven fabric. Here, Pc is the capillary pressure (N / m ² ) of the nonwoven fabric, γ _L is the surface tension (N / m) of the liquid, θ is the contact angle (rad) between the fiber and the liquid, and r is Fiber diameter (m). k is a correction coefficient considering factors such as the ratio of voids per volume of the nonwoven fabric, and the capillary pressure can be obtained more accurately by calibrating with this correction coefficient.

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 a plate method such as DY-200 manufactured by Kyowa Interface Science Co., Ltd. H. It is set as the average value measured 10 times in the environment. The fiber diameter was measured with 30 scanning magnifications at an observation magnification of 350 times from observation with a scanning electron microscope, and this was taken as an average value obtained by randomly measuring 150 fiber diameters at a total of 5 locations. The contact angle between the fiber and the liquid is determined by identifying the constituent fibers of the nonwoven fabric by Fourier transform infrared spectroscopy (FTIR) and measuring the contact angle on a resin plate having the same composition. Specifically, the contact angle when 3 seconds elapses 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 five locations on the plate, and the average value is obtained. . In addition, when there are a plurality of fiber materials, the contact angle is measured in the same manner for each material, and the value at the time of Pc calculation is a weighted average of the contact angles based on the surface area ratio of each fiber component. Of θ.

As is clear from the above formula, the capillary pressure increases as the fiber diameter decreases (thinners). In the present invention, the capillary pressure on the first surface side is increased by reducing the fiber diameter. When the amount of wiping liquid contained in the fiber assembly on the first surface side is reduced or eliminated, the wiping liquid carried on the fiber assembly on the second surface side is reduced due to the difference in capillary pressure. It is drawn into the body. As a result, an appropriate amount of wiping liquid is supplied to the fiber aggregate on the first surface side, and an amount of wiping liquid suitable for wiping always exists on the first surface side.

In addition, the area ratio of the fiber having a small fiber diameter on the first surface of the wet wiping sheet surface including voids is preferably 40% or more and 99% or less, more preferably 45% or more and 95% or less, and more preferably 50% or more. 90% or less is more preferable. On the other hand, the area ratio occupied by the fine fibers on the second surface is preferably 0% or more and 55% or less. The area occupied by the fibers having a small fiber diameter on the first surface is obtained, for example, by measuring the area occupied by the fibers having a small fiber diameter from an image or a photograph obtained by imaging the first surface. Hereinafter, the area occupied by each fiber 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 fiber by the area to be measured. In the case of% display, the value is 100 times the divided value.

Here, for example, the remaining 1% of the upper limit of 99% in the area ratio of 40% to 99% is a void. This gap is necessary for the wiping liquid to be discharged with respect to the first surface. By adjusting the ratio of the voids, the amount of wiping liquid released to wipe off the dirt on the surface to be wiped can be suppressed to a necessary amount even if the surface is wiped strongly. Further, by setting the area ratio occupied by the fibers having a small fiber diameter on the second surface as described above, as a result, the number of voids increases and the amount of wiping liquid carried increases. When the area ratio of the fibers having a small fiber diameter on the first surface is equal to or more than the lower limit value, an appropriate amount of the wiping liquid is released, so that it is not released more than the necessary amount. Therefore, the area that can be wiped widens.

In the present invention, in the plane parallel to the first surface, the area ratio occupied by the fibers having a small fiber diameter is stepped, curved, or a combination thereof in the thickness direction on the opposite surface side of the first surface. It is preferable that the value is decreased. In particular, from the second surface, the amount of wiping liquid supported is 50% or more and 100% or less of the thickness of the wet wiping sheet, and the area ratio occupied by the thin fiber is 50% or more and 100% or less. Can be increased. Here, the ratio of the thickness that makes the area ratio occupied by the fibers having a small fiber diameter in the range of 50% to 100% is preferably 1% to 90%, more preferably 5% to 70%, 7% or more and 50% or less are more preferable. In addition, by setting it as the preferable ratio of thickness as mentioned above, the quantity of the wiping liquid discharge | released in order to wipe off the stain | pollution | contamination of a wiping object surface can be discharge | released.

Here, a confocal laser microscope can be used to obtain information inside the wet wiping sheet. By using a confocal laser microscope, a spectrum inside the sample can be obtained. For example, by performing Raman imaging of the sample in the depth direction, the component distribution inside the sample can be observed nondestructively.

In the present invention, the liquid discharge layer includes at least two layers, ie, a liquid retaining layer that carries the wiping liquid and a liquid discharge layer, and the liquid discharge layer includes the first surface. In particular, in order to carry a large amount of wiping liquid, as described above, from the second surface, 50% to 100% of the thickness of the wet wiping sheet, and the area ratio occupied by the fibers having a small fiber diameter are 1%. More than 100%. As a result, a liquid retaining layer that carries most of the wiping liquid can be obtained. On the other hand, the liquid discharge layer is a part other than the liquid retention layer including the first surface.

In the present invention, the basis weight of the fiber is preferably 1 g / m ² or more and 100 g / m ² or less, more preferably 5 g / m ² or more and 50 g / m ² or less, and more preferably 10 g / m ² or more and 30 g / m ² on the first surface side. The following is more preferable. On the other hand, on the second surface side, 10 g / m ² or more and 50 g / m ² or less is preferable, 15 g / m ² or more and 30 g / m ² or less is more preferable, and 20 g / m ² or more and 25 g / m ² or less is more preferable.

In the present invention, it is particularly preferable that fibers having different fiber diameters are entangled without being thermally fused to each other. By doing in this way, the space | gap between fibers increases compared with the case where it heat-seal | fuses, and the load of a wiping liquid increases.

In the wet wiping sheet of the present invention, the wiping liquid is discharged from the first surface to the wiping target surface by wiping once, that is, wiping the wiping target surface once. The amount of the wiping liquid released after each wiping is preferably 0.5 g / tatami or more, more preferably 0.7 g / tatami or more, and further preferably 1.0 g / tatami or more. The upper limit of the amount released is realistically 8 g / tatami or less, preferably 7 g / tatami or less, more preferably 6 g / tatami or less. When the discharge amount is equal to or greater than the lower limit value, sufficient wiping can be performed, and when the discharge amount is equal to or less than the upper limit value, a wiping liquid residue hardly occurs on the first surface. Here, the tatami mat has a size of 1820 mm × 910 mm and a tatami mat area of 1.6552 m ² .

FIG. 6 is a graph showing the results of examining the amount of liquid released per tatami when wiping the flooring floor one tatami. Thus, the liquid discharge | release amount per tatami (g) is measured, By plotting this, the discharge | release behavior of a liquid can be estimated.
The measurement conditions of the release behavior are a wiping load (load W) of 0.16 kN / m ² and a wiping speed (speed V) of 1 m / s. In the present invention, the amount released per tatami is preferably 1 g or more, and the upper limit is preferably 10 g or less.

In the present invention, the maximum liquid carrying amount that can be carried on the wet wiping sheet, that is, the initial liquid carrying amount is preferably 1 g / sheet or more, more preferably 10 g / sheet or more, and further preferably 12 g / sheet or more. The upper limit of the initial liquid carrying amount is realistically 40 g / sheet or less, preferably 30 g / sheet or less, more preferably 20 g / sheet or less.

By doing in this way, it becomes possible to discharge a liquid of 1 g / tatami or more per target wiping, and it is possible to sustain more than 6 tatami mats.

<Wiping solution>
Generally, the wiping liquid used in the wet wiping sheet is applied as the wiping liquid.
That is, the wiping liquid may be water alone or an aqueous solution containing a surfactant, but an aqueous solution containing a surfactant is preferable.

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

The wiping solution may contain an additive. Examples of additives include polymers of acrylic acid, methacrylic acid or maleic acid, or salts thereof, and copolymers of maleic acid with other vinyl monomers or salts for the purpose of enhancing the rinsing effect. Is mentioned. Moreover, water-soluble organic solvents, such as a disinfectant, a fragrance | flavor, a fragrance | flavor, a deodorizer, an abrasive particle, a pH adjuster, alcohol, etc. are mentioned.

The content of the surfactant and the additive as described above is generally used within the range used in the wet wiping sheet.

<< Method for manufacturing wet wiping sheet >>
In the wet wiping sheet according to the present invention, at least two types of fibers having different fiber diameters are entangled. In the production process of the present invention, a water stream is sprayed on a laminate of at least two layers of fiber aggregates having different fiber diameters in the fiber aggregates constituting each layer, and one fiber aggregate is in contact with the other fiber aggregate. Includes a water entanglement process that allows a portion to enter. In particular, by interleaving part of the other fiber assembly into one fiber assembly by the hydroentanglement method, fusion between fibers as in the confounding method using hot air does not substantially occur.

In the present invention, it is preferable that the water stream is sprayed at least from the layer side of the fiber assembly made of fibers having a thin fiber diameter of the laminate. In this case, a non-woven fabric or net different from this layer is arranged on the fiber assembly layer composed of fibers having a thin fiber diameter, and water is sprayed from the arranged non-woven fabric or net side, and then arranged. The nonwoven fabric or net may be peeled off. This aspect is a more preferable aspect in the present invention. In addition, it is a further preferable aspect to further spray a water stream from a layer of a fiber aggregate composed of fibers having a small fiber diameter after peeling the arranged nonwoven fabric or net.

The fiber diameters of the thin fiber diameter and the thick fiber diameter are the same as described above, and the fiber lengths of the thin fiber diameter and the large fiber diameter are also as described above.

The basis weight of the fiber assembly composed of fibers having a thin fiber diameter of the laminate is preferably 1 g / m ² or more and 100 g / m ² or less, more preferably 5 g / m ² or more and 50 g / m ² or less, and more preferably 10 g / m ² or more and 30 g. / M ² or less is more preferable. The basis weight of the fiber aggregate composed of fibers having a large fiber diameter of the laminate is preferably 10 g / m ² or more and 50 g / m ² or less, more preferably 15 g / m ² or more and 30 g / m ² or less, and more preferably 20 g / m ² or more and 25 g. / M ² or less is more preferable.

In addition, when a non-woven fabric different from this layer is disposed on the fiber assembly layer composed of fibers having a small fiber diameter, the basis weight of the non-woven fabric is preferably 11 g / m ² or more and 150 g / m ² or less, and 20 g / m. ^{2 to} 80 g / m ² is more preferable, and 30 g / m ^{2 to} 75 g / m ² is more preferable. Here, in the present invention, the nonwoven fabric may be a fiber assembly composed of fibers having a large fiber diameter under a fiber assembly layer composed of fibers having a small fiber diameter. is there.

In the present invention, in the hydroentanglement method (water needling) to be applied, the entangling energy applied to the laminated body of fiber assemblies can be controlled by the number of water jet nozzles and the conditions such as water pressure and line speed.

Here, a non-woven fabric or a net different from this layer is arranged on a layer of fiber aggregates composed of fibers having a thin fiber diameter, placed on a conveyor belt constituted by a perforated mesh, and arranged on the conveyor belt. Spray water from the nonwoven fabric or net side. Then, after the arranged non-woven fabric or net is peeled off, a water stream is further sprayed from the layer side of the fiber assembly made of fibers having a small fiber diameter. In this case, conditions such as the number of water jet nozzles for the second time, water pressure, and line speed may be changed from those for the first time.

In the present invention, it is preferable to place a laminated body composed of fiber aggregates on a perforated mesh outer shell, and suck from the side opposite to the side where the laminated bodies composed of fiber aggregates are placed.
The perforated mesh outer shell may be flat or circular, but a circular shape is efficient and preferable.

In the present invention, when the hydroentanglement method is applied, the fibers may be fibrillated, but the fiber diameter of the obtained thin fibers is preferably 0.1 μm or more and 9 μm or less.

In the present invention, after the hydroentanglement step, the wiping liquid is supported on the fiber assembly on the second surface side in which the ratio of fibers having a large fiber diameter is high. The content of the wiping liquid (supported amount of fiber aggregate) is preferably 1 g / sheet or more, more preferably 10 g / sheet or more, and further preferably 12 g / sheet or more. The upper limit of the content of the wiping liquid is realistically 40 g / sheet or less, preferably 30 g / sheet or less, and more preferably 20 g / sheet or less.
Examples of the method of containing the wiping liquid include a method of spraying the liquid in a roll-to-roll line, a method of passing the liquid storage pool by roll-to-roll, a method of applying the liquid after cutting and laminating, and the like in the roll-to-roll line. A method of spraying the liquid is preferable.

<The manufacturing method of the fiber assembly which consists of a fiber with a thin fiber diameter among fiber assemblies>
As the fiber assembly composed of fibers having a small fiber diameter, a commercially available fiber assembly composed of fibers having a small fiber diameter may be used. However, in the present invention, the melt type electrospinning method (melting electrospinning method) is used. ).

The apparatus for carrying out the melt type electrospinning method is not particularly limited as long as it can realize the melt type electrospinning method. The apparatus includes a heating and melting unit for heating and melting the thermoplastic resin, and an electrostatic spinning unit that applies a voltage to the heated and melted thermoplastic resin to extend the thermoplastic resin into a fibrous shape. Yes. Furthermore, a collecting unit for collecting the elongated microfibers on the collector by electric attraction is provided.

The heating means of the heating and melting unit may be any means as long as it is performed by the melt-type electrostatic spinning method, and any means may be used.
Also, the electrospinning unit may be any unit as long as it is a unit performed by the melt type electrospinning method, and any unit may be used. In addition, it is preferable that a heating part has a heating space part which can control temperature and can pass the elongate fiber 30 mm or more.
The collection unit may be composed of a collector for collecting ultrafine fibers.

The obtained spinning is collected by a collector, laminated and spread into a sheet (web), and a non-woven fiber assembly is produced.

In the present invention, there is no weaving process, and a heat-shrinkable net-like net is not required, compared with a manufacturing method in which a process of applying a hydroentanglement method and a process of thermally shrinking a highly shrinkable fiber of a nonwoven fabric are performed, The number of processes is small, simple and inexpensive mass production is possible.

<< Use of wet wiping sheet >>
The wet wiping sheet of the present invention can be provided with various functions by controlling voids, layer structure, wettability and the like. For this reason, the wet wiping sheet of the present invention is, for example, a building such as a floor surface, a wall surface, a closet, a window glass, a mirror, a door, a door knob and other furniture, a rug, a carpet, a table and other furniture, a kitchen, a toilet, etc. Can be used for wiping equipment. It can also be used for cleaning wipers, and can also be used for cleaning the face and body, as well as sanitary goods, civil engineering, and packaging.

Here, FIGS. 5 to 7 show typical wet wiping sheets of the present invention produced as described above. Specifically, a fiber assembly composed of fibers having a small fiber diameter was formed by a melt type electrospinning method. The fiber was polypropylene, and the obtained spinning diameter, that is, the fiber diameter was 0.6 to 3 μm. Polyethylene terephthalate, rayon, and acrylic mixed cotton non-woven fabric having a fiber diameter of 10 to 18 μm was used as an aggregate of fibers having a large fiber diameter.

The basis weight of the nonwoven fabric composed of an aggregate of fibers having a large fiber diameter was 65 g / m ² , and the basis weight of a fiber aggregate composed of the manufactured fibers having a small fiber diameter was 55 g / m ² . A high-pressure jet water stream is sprayed again from the side of the fiber assembly made of thin fibers between two non-woven fabrics of the aggregate made of thick fibers, so that one fiber assembly I got a part in. The basis weight of the fiber in the whole obtained sheet was 120 g / m ² .

The photograph which observed the sheet | seat cross section of this sheet | seat with the scanning electron microscope is FIG.
The upper side of the figure is the first surface (wiping surface).

Then, as a result of injecting the wiping liquid from the nonwoven fabric side of the aggregate composed of fibers having a large fiber diameter, the content could be 7.8 g / sheet. FIG. 6 shows a plot of the relationship between the liquid discharge amount per tatami (g) and the wiping area (tatami) using the wet wiping sheet thus manufactured.

As shown in FIG. 6, the liquid discharge amount per 1 tatami was 1 g or more until the 7th tatami mat. In addition, the release rate of the 14th tatami mat was 81%. In addition, the impregnation rate was determined as impregnating liquid mass / fiber mass × 100, and was 380%.
The frictional resistance was 1.6 N, which was lower than that of a sheet having a fiber diameter of 0.3 to 3 μm, but almost the same as a microfiber sheet having a fiber diameter of 10 to 18 μm.

Here, the frictional resistance is measured by attaching a wiper head to the push-pull gauge, scanning so that the angle of the push-pull gauge is parallel to the wiping plane, measuring the maximum value of the stress, and plotting it. Asked.

FIG. 7 is a photograph of the first surface after wiping using the above-described wet wiping sheet, and it is observed that uneven portions are not uniform and are clogged with dirt. In FIG. 7, the above-described photographic observation suggests that dirt that could not be removed in the past has also been removed.

As described above, according to the present invention, it is possible to provide a wet wiping sheet that can be wiped lightly to remove dirt, and does not need to be replaced even when the wiping area is large, or can be replaced less frequently. Furthermore, it is possible to provide a method for manufacturing a wet wiping sheet that is simple and capable of mass production.

Regarding the above-described embodiment, the present invention discloses the following wet wiping sheet including the wet wiping sheet and a manufacturing method thereof.

(1) A wet wiping sheet having a first surface and a second surface that is the opposite surface of the first surface, and comprising a fiber assembly of at least two types of fibers having different fiber diameters,
The at least two kinds of fibers having different fiber diameters are entangled,
Of the fibers in the fiber assembly, the proportion of fibers having a small fiber diameter is greater on the first surface side than on the second surface side, and among the fibers in the fiber assembly, fibers having a large fiber diameter exist. The ratio is higher on the second surface side than on the first surface side, and the capillary pressure on the first surface side is higher than that on the second surface side,
A wet wiping sheet in which a wiping liquid is carried on at least the fiber assembly on the second surface side.
(2) The wet wiping sheet according to (1), wherein the at least two kinds of fibers having different fiber diameters are entangled without being thermally fused to each other.
(3) The wet wiping sheet according to (1) or (2), wherein an aggregate of fibers having a small fiber diameter and a fiber having a large fiber diameter are present on the first surface of the wet wiping sheet.
(4) The area ratio of fibers having a small fiber diameter on the first surface is 40% or more and 99% or less, preferably 45% or more and 95% or less, and more preferably 50% or more and 90% or less. The wet wiping sheet according to any one of (3).
(5) The wet fiber according to any one of (1) to (4), wherein among the fibers having different fiber diameters, the fibers having a small fiber diameter are 0.1 μm or more and 9 μm or less, preferably 0.5 μm or more and 5 μm or less. Wiping sheet.
(6) The wet wiping according to any one of (1) to (5), wherein a fiber having a larger fiber diameter among fibers having different fiber diameters is 10 μm to 30 μm, preferably 15 μm to 25 μm. Sheet.
(7) The wet wiping sheet according to any one of (1) to (6), wherein fibers having different fiber diameters are fibers having the same component.
(8) The wet wiping sheet according to any one of (1) to (6), wherein the fibers having different fiber diameters are fibers having different components.
(9) The wet wiping sheet is composed of at least two layers of a liquid retaining layer that carries the wiping liquid and a liquid discharge layer, and the liquid discharge layer includes any one of the first surfaces (1) to (8) The wet wiping sheet according to claim 1.
(10) From the second surface, 50% or more and 100% or less of the thickness of the wet wiping sheet, the area ratio occupied by fibers having a small fiber diameter is 1% or more and 100% or less, and the wiping is performed on the second surface side. The wet wiping sheet according to any one of (1) to (9), wherein a liquid retaining layer supporting a large amount of liquid is disposed.
(11) The amount of wiping liquid released from the first surface to the wiping target surface by wiping the wiping target surface once is 0.5 g / tatami or more, preferably 0.7 g / tatami or more, more preferably 1 The wet wiping sheet according to any one of (1) to (10), which is 0.0 g / tatami mat or more (tatami mat has an area of 1.6552 m ² ).
(12) The amount of wiping liquid released from the first surface to the wiping target surface by wiping the wiping target surface once is 8 g / tatami or less, preferably 7 g / tatami or less, more preferably 6 g / tatami or less. The wet wiping sheet according to any one of (1) to (11), wherein the tatami mat has an area of 1.6552 m ² .
(13) The wet wiping sheet according to any one of (1) to (12), wherein the amount of the wiping liquid supported is larger than the amount supported on the fiber assembly on the opposite side of the first surface.

(14) The method for producing a wet wiping sheet according to any one of (1) to (13),
A water stream in which a water stream is sprayed on a laminate composed of at least two layers of fiber aggregates having different fiber diameters in the fiber aggregates constituting each layer, and a part of the other fiber aggregate is introduced into one of the fiber aggregates. Including the confounding process,
A method for producing a wet wiping sheet, wherein the water stream is sprayed at least from the layer side of a fiber assembly made of fibers having a thin fiber diameter of the laminate.
(15) In the hydroentanglement step, a non-woven fabric or a net different from the layer is arranged on a layer of a fiber assembly composed of fibers having a small fiber diameter, and spraying of the water flow is performed from the arranged non-woven fabric or net side. Done
The method for producing a wet wiping sheet according to (14), wherein after the water stream is sprayed, the provided non-woven fabric or net is peeled off.
(16) The method for producing a wet wiping sheet according to (15), wherein after the non-woven fabric or net is peeled off, the water flow is further sprayed from the layer side of the fiber assembly made of fibers having a thin fiber diameter of the laminate. .
(17) The method for producing a wet wiping sheet according to any one of (14) to (16), wherein a fiber aggregate composed of fibers having a small fiber diameter is formed by a melt-type electrostatic spinning method. .
(18) The laminate according to any one of (14) to (17), wherein a laminate composed of a fiber assembly is placed on a perforated mesh outer shell, and suction is performed from a side opposite to the side on which the laminate composed of the fiber assembly is placed. Manufacturing method of wet wiping sheet.
(19) The method for producing a wet wiping sheet according to any one of (14) to (18), wherein the fibers are fibrillated by a hydroentanglement method.

While the invention has been described in conjunction with embodiments and examples thereof, it is not intended that the invention be limited in any detail to the description, unless otherwise specified, and that the spirit and nature of the invention as set forth in the appended claims be considered as such. I think it should be interpreted broadly without violating the scope.

This application claims priority based on Japanese Patent Application No. 2016-236112 filed in Japan on December 5, 2016 and Japanese Patent Application No. 2017-154681 filed on August 9, 2017 in Japan. Which are hereby incorporated by reference herein as part of their description.

Claims

A wet wiping sheet having a first surface and a second surface opposite to the first surface, and comprising a fiber assembly of at least two types of fibers having different fiber diameters,
The at least two kinds of fibers having different fiber diameters are entangled,
Of the fibers in the fiber assembly, the proportion of fibers having a small fiber diameter is greater on the first surface side than on the second surface side, and among the fibers in the fiber assembly, fibers having a large fiber diameter exist. The ratio is higher on the second surface side than on the first surface side, and the capillary pressure on the first surface side is higher than that on the second surface side,
A wet wiping sheet in which a wiping liquid is carried on at least the fiber assembly on the second surface side.
The wet wiping sheet according to claim 1, wherein the at least two types of fibers having different fiber diameters are entangled without being thermally fused to each other.
The wet wiping sheet according to claim 1 or 2, wherein an aggregate of the fibers having a small fiber diameter and a fiber having a large fiber diameter are present on the first surface of the wet wiping sheet.
The wet wiping sheet according to any one of claims 1 to 3, wherein an area ratio of the fibers having a small fiber diameter on the first surface is 40% or more and 99% or less.
The wet wiping sheet according to any one of claims 1 to 4, wherein among the fibers having different fiber diameters, the fibers having a small fiber diameter are 0.1 µm or more and 9 µm or less.
The wet wiping sheet according to any one of claims 1 to 5, wherein, among the fiber diameters of the fibers having different fiber diameters, the fiber having a large fiber diameter is 10 μm or more and 30 μm or less.
The wet wiping sheet according to any one of claims 1 to 6, wherein the fibers having different fiber diameters are fibers having the same component.
The wet wiping sheet according to any one of claims 1 to 6, wherein the fibers having different fiber diameters are fibers having different components.
The wet wiping sheet is composed of at least two layers of a liquid retaining layer that carries the wiping liquid and a liquid discharge layer, and the liquid discharge layer includes the first surface. Wet wiping sheet.
50% or more and 100% or less of the thickness of the wet wiping sheet from the second surface, and the area ratio occupied by the fibers having a small fiber diameter is 1% or more and 100% or less, and the wiping liquid is disposed on the second surface side. The wet wiping sheet according to any one of claims 1 to 9, wherein a liquid-retaining layer supporting a large amount of the liquid is disposed.
The amount of the wiping liquid discharged from the first surface to the wiping target surface by wiping the wiping target surface once is 0.5 g / tatami or more (however, the area of the tatami mat is 1.6552 m 2 ). The wet wiping sheet according to any one of claims 1 to 10.
The amount of the wiping liquid discharged from the first surface to the wiping target surface by wiping the wiping target surface once is 8 g / tatami or less (the tatami mat has an area of 1.6552 m 2 ). The wet wiping sheet according to any one of 1 to 11.
The wet wiping sheet according to any one of claims 1 to 12, wherein the amount of the wiping liquid supported is larger than the amount supported on the fiber assembly on the opposite side of the first surface.
A method for producing a wet wiping sheet according to any one of claims 1 to 13,
A water stream in which a water stream is sprayed on a laminate composed of at least two layers of fiber aggregates having different fiber diameters in the fiber aggregates constituting each layer, and a part of the other fiber aggregate is introduced into one of the fiber aggregates. Including the confounding process,
A method for producing a wet wiping sheet, wherein the water stream is sprayed at least from the layer side of a fiber assembly made of fibers having a thin fiber diameter of the laminate.
The hydroentanglement step is performed by arranging a non-woven fabric or a net different from the layer on a fiber assembly layer composed of fibers having a small fiber diameter, and spraying the water flow from the arranged non-woven fabric or net side,
The manufacturing method of the wet wiping of Claim 14 which peels the distribute | arranged said nonwoven fabric or net | network after spraying a water flow.
The method for producing a wet wiping sheet according to claim 15, wherein after the non-woven fabric or net is peeled off, a water stream is further sprayed from the layer side of the fiber assembly made of fibers having a thin fiber diameter of the laminate.
The method for producing a wet wiping sheet according to any one of claims 14 to 16, wherein, among the fiber aggregates, a fiber aggregate composed of fibers having a small fiber diameter is formed by a melt type electrospinning method.
The wet type according to any one of claims 14 to 17, wherein a laminate made of the fiber assembly is placed on a perforated mesh outer shell, and suction is performed from a side opposite to the side on which the laminate made of the fiber assembly is placed. Manufacturing method of wiping sheet.
The method for producing a wet wiping sheet according to any one of claims 14 to 18, wherein the fibers are fibrillated by a hydroentanglement method.