TWI748015B - Wet wiping sheet and manufacturing method thereof - Google Patents

Abstract

The wet wiping sheet of the present invention has a first side and a second side opposite to the first side, and includes a fiber assembly of at least two fibers with different fiber diameters, and the above-mentioned at least two fiber diameters are different Fiber entanglement, the ratio of fibers with smaller fiber diameters in the fibers of the fiber assembly is more on the first surface side than the second surface side, and fibers with larger fiber diameters exist in the fibers of the fiber assembly The ratio is that the second surface side is more than the first surface side, and the capillary pressure of the first surface side is higher than the second surface side, and at least the fiber assembly on the second surface side carries wiper liquid.

Description

Wet wiping sheet and manufacturing method thereof

The present invention relates to a wet wiping sheet.

In the past, wet wiping sheets such as cleaning wipes and sanitary products are products that are used daily, so the required performance has been improved and research has been actively carried out, and the performance has been improved day by day. For example, in order to improve wiping performance, friction resistance, and heat resistance, it is proposed to contain 50% by mass or more of liquid crystal polyester and to fibrillate the fiber diameter of the surface layer to 0.5 μm or less (see Patent Document 1). In addition, regarding the first layer closest to the absorber, when the fiber density is high and a large amount of liquid is discharged to the surface sheet, it becomes difficult to transfer the liquid to the absorber. Therefore, it has been proposed to use a non-woven fabric that does not hinder the transfer of liquid from the front sheet to the absorber and has low diffusibility when the liquid penetrates (refer to Patent Document 2).

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2013-159887

[Patent Document 2] Japanese Patent Laid-Open No. 2008-144322

The present invention is a wet wiping sheet, which has a first side and a second side opposite to the first side and includes at least two types of fibers with different fiber diameters, and the above-mentioned at least two types of fibers Fibers with different diameters are intertwined, and among the fibers of the above-mentioned fiber assembly, there are fibers with a smaller fiber diameter. The ratio in the first surface side is more than that in the second surface side, and the ratio of fibers with a larger fiber diameter in the fibers of the fiber assembly is more on the second surface side than the first surface side, In addition, the capillary pressure on the first surface side is higher than the second surface side, and at least the fiber assembly on the second surface side carries a wiping liquid.

The above-mentioned and other features and advantages of the present invention are made more clear from the following description with appropriate reference to the accompanying drawings.

Fig. 1 is a schematic substitute photograph obtained by photographing the first side of the wet wiping sheet of the present invention using a scanning electron microscope.

Fig. 2 is a schematic substitute photograph obtained by using a scanning electron microscope to take the second side of the wet wiping sheet of the present invention.

Fig. 3 is a schematic substitute photograph obtained by using a scanning electron microscope to take a part of the cross-section of the wet wiping sheet of the present invention.

Fig. 4 is a schematic substitute photograph obtained by using a scanning electron microscope to take another part of the cross-section of the wet wiping sheet of the present invention.

Fig. 5 is a schematic substitute photograph obtained by using a scanning electron microscope to take a part of the cross-section of the representative wet wiping sheet of the present invention.

Figure 6 is a graph obtained by measuring the liquid release amount (g) and wiping area (stacking mat) of each stacked mat using the representative wet wiping sheet of the present invention produced picture.

Fig. 7 is a schematic substitute photograph showing the first side of the representative wet wiping sheet of the present invention manufactured.

The inventors of the present invention conducted research on the prior art including the above-mentioned proposal. close In the previous wet wiping sheet containing the wiping liquid, in one dirt wipe (1 wipe), more than the amount of wiping liquid required to wipe the dirt on the wiping surface is released to the wiping surface. Therefore, it can be seen that there is room for further improvement. This is especially a problem when the dirt cannot be removed without rubbing hard to remove the dirt. That is, the amount of wiping liquid required to wipe off the dirt on the wiping target surface is released to the wiping target surface. Therefore, in the case of wiping with a large wiping area such as a rug, a carpet, and a floor, it is frequently replaced with a new wet wiping sheet in the middle of wiping.

Therefore, the present invention relates to a wet wiping sheet that removes dirt by wiping lightly and does not need to be replaced even if the wiping area is large, or the number of replacements is less.

The inventors of the present invention have conducted various studies on methods of preventing the wiping liquid from being released to the wiping target surface in an amount more than the amount required to wipe off the dirt on the wiping target surface, especially when wiping strongly. As a result, it was found that the above-mentioned problem can be solved by using at least two types of fibers having different fiber diameters as described above, and controlling the existence state and capillary pressure of fibers with a thinner fiber diameter, and completed the present invention. The so-called wiping in the present invention includes two meanings of cleaning and wiping, which means all wiping conditions. For example, it includes the cleaning of floors, walls, ceilings, columns and other buildings; the cleaning of fixtures such as sliding doors and windows or houses; the wiping of objects; the wiping of the body and body-related appliances, etc.

According to the present invention, it is possible to provide a wet wiping sheet that can remove dirt by wiping lightly and will not be replaced even if the wiping area is large, or the number of replacements is small.

Hereinafter, the wet wiping sheet of the present invention and its manufacturing method will be described based on its preferred embodiments.

First, the wet wiping sheet will be described.

<<Wet Wipe 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, one of the surfaces forming the front and back surfaces of the wet wiping sheet (for example, the front surface) is referred to as the first surface, and the other surface (for example, the back surface) is referred to as the second surface. Hereinafter, for example, the first surface will be described as the wiping surface. The so-called wiping surface is the surface on which the wiping liquid is released. The wet wiping sheet includes at least two fiber aggregates of fibers with different fiber diameters, and at least two fibers with different fiber diameters are intertwined. There are two kinds of fibers with different fiber diameters (a thicker fiber and a relatively thin fiber) on the first surface side and the second surface side, at least the fiber with the thinner fiber diameter. In the fiber assembly, among the fibers having the above two types of fiber diameters, the ratio of fibers with smaller fiber diameters is more on the first surface side than on the second surface side (see FIG. 1). In addition, in the fiber assembly, the ratio of fibers having a relatively thick fiber diameter is more on the second surface side than on the first surface side (see FIG. 2). And the capillary pressure on the first surface side is higher than the second surface side. Furthermore, the wiping liquid is carried on at least the fiber assembly on the second surface side.

Furthermore, the above-mentioned fiber assembly system is a fiber assembly formed by entanglement of mutual fibers as the main body and compounded. In addition, the so-called wiping liquid carried on the fiber assembly at least on the second surface side means that the fiber assembly on the second surface side contains the wiping fluid, and it is also included in the fiber assembly on the first surface side. The wiping liquid is contained in the gap. Regarding the amount of the wiping liquid carried, it is preferable that the amount carried by the fiber assembly on the second surface side is greater than the amount carried by the fiber assembly on the first surface side.

First, based on Figures 1 to 4 of the drawings, the description will be made using scanning electron microscope (SEM, scanning electron microscope) photographs of the wet wiping sheet of the present invention.

Figs. 3 and 4 are photographs of different parts of the cross-section obtained by cutting the wet wiping sheet of the present invention with a cutter. Figures 3 and 4 both show that there is a fiber assembly including fibers with a thinner fiber diameter on the upper side of the figure, and the upper side is the first side (front side). Therefore, the surface on the lower side of the figure is the second surface (rear surface).

As shown in Figure 1, if the wet wipe of the present invention is observed from above through a scanning electron microscope On the first side of the sheet, it was confirmed that it contained an aggregate of fibers with a smaller fiber diameter and fibers with a larger fiber diameter. In the first side of the wet wiping sheet, there are more fibers with a smaller fiber diameter than fibers with a larger fiber diameter. It is also clear from FIG. 1 that the entire surface of the first surface is a fiber assembly including fibers with a relatively thick fiber diameter in a fiber assembly including fibers with a relatively small fiber diameter, and not a fiber assembly including fibers with a relatively small fiber diameter.

On the other hand, as shown in Fig. 2, if the second side of the wet wiping sheet of the present invention is observed from above with a scanning electron microscope, it is confirmed that the aggregates of the fibers with the thicker fiber diameter and the thinner fiber diameter The fiber. In the second surface of the wet wiping sheet, there are more fibers with a larger fiber diameter than fibers with a smaller fiber diameter. It is also clear from FIG. 2 that the entire surface of the second surface is a fiber assembly including fibers with a relatively thick fiber diameter, rather than a fiber assembly including fibers with a relatively thick fiber diameter.

Furthermore, the observation range of the scanning electron microscope in Figs. 1 and 2 is 290 μm×380 μm and magnified to 330 times. The observation range of the scanning electron microscopes in Figures 3 and 4 is 170μm×240μm and magnified to 500 times.

<fiber>

The fibers constituting the fiber assembly in the present invention are at least two types of fibers having different fiber diameters. Regarding fibers, polyester, polyamide, polyolefin, cellulose fibers, or fibers made from various metals, glass, and minerals are representative. Among them, polyester, polyamide, polyolefin, and cellulose fibers are preferred.

The polyester may be any polyester as long as it has a structure having an ester bond in the polymer main chain. For example, polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN) can be cited , Polybutylene naphthalate (PBN).

Polyolefins can be obtained from monomers having ethylenic unsaturated groups. Examples include polyethylene, polypropylene, ethylene-propylene copolymers, polyvinyl acetate, ethylene-vinyl acetate copolymers, cyclic acetals of polyvinyl alcohol, acrylic resins (including acrylic resins and methacrylic resins), PVC.

The polyolefin is as described above, and 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 nylons such as nylon 6, nylon 11, and nylon 12; co-condensation nylons such as nylon 66, nylon 610, nylon 612, nylon 6T, nylon 6I, nylon 9T, and nylon M5T can be cited. Moreover, the polyamide obtained from the following diamine component and dicarboxylic acid component can be mentioned.

As the diamine component, tetramethylene diamine, pentamethylene diamine, 2-methylpentamethylene diamine, hexamethylene diamine, heptamethylene diamine, octamethylene diamine, Nonamethylene diamine, decamethylene diamine, dodecamethylene diamine, 2,2,4-trimethyl-hexamethylene diamine, 2,4,4-trimethylhexamethylene Aliphatic diamine compounds such as methyl diamine. In addition, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, and 1,4-diaminocyclohexane can be cited Cyclohexane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminomethyl)decahydronaphthalene, bis(aminomethyl)tricyclodecane And other alicyclic diamine compounds. Furthermore, diamine compounds having aromatic rings, such as meta-xylylenediamine, paraxylylenediamine, bis(4-aminophenyl)ether, paraphenylenediamine, and bis(aminomethyl)naphthalene, can be cited.

As the carboxylic acid component, aliphatic two such as succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, etc. Carboxylic acid compound. Moreover, phthalic acid compounds, such as isophthalic acid, terephthalic acid, and phthalic acid, are mentioned. Furthermore, 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 Acid, 2,7-naphthalenedicarboxylic acid and other naphthalenedicarboxylic acid compounds.

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

Cellulose fibers may be natural fibers or synthetic fibers. Examples of synthetic fibers include acylated fibers such as cellulose acetate.

In addition, these mixed fibers can also be cited, such as polyethylene/polyethylene terephthalate, polypropylene/polyethylene terephthalate, and the like.

In the present invention, among the above-mentioned fibers, polyethylene terephthalate, polypropylene, acrylic resin, nylon, and cellulose fibers are more preferred. The acrylic resin (especially acrylic) preferably has a repeating unit derived from its ester, methacrylic acid or methacrylic acid ester.

The fiber length of the fiber, that is, the average fiber length of the entire 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 still more preferably 20 mm or more and 60 mm or less.

From the viewpoint of giving the difference in capillary pressure described below, the difference between the fiber diameter of the finer fiber and the fiber diameter of the thicker fiber among the fiber diameters of fibers with different fiber diameters is preferably 1 μm or more and 29.9 μm or less, more preferably 2 μm or more and 28 μm or less, more preferably 5 μm or more and 27 μm or less.

In addition, among the fiber diameters of fibers with different fiber diameters, the fiber diameter of the finer 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 still more preferably 0.5 μm or more and 5 μm or less. Among the fiber diameters of fibers with different fiber diameters, the fiber diameter of the thicker fiber is preferably 10 μm or more and 30 μm or less, more preferably 11 μm or more and 28 μm or less, and still more preferably 15 μm or more and 25 μm or less. Fibers with thinner fiber diameters and fibers with thicker fiber diameters can be selected with the wiping function.

Fibers with different fiber diameters may be fibers of the same composition as each other, or fibers of different compositions. In the present invention, fibers of the same composition are preferred. In addition, the fiber length may be different or the same among the fibers of each other, and in the present invention, fibers of the same fiber length are preferred.

In the present invention, at least two kinds of fibers with different fiber diameters are intertwined. The ratio of fibers with a thinner fiber diameter is more on the first side than on the second side, and the ratio of fibers with a larger fiber diameter is more on the second side than on the first side, and the first side The capillary pressure on the side is higher than that on the second side. Thereby, during wiping, even when wiping hard, the amount of wiping liquid released for wiping off the dirt on the surface to be wiped can be controlled to a necessary amount. Therefore, in the case of wiping with a large wiping area such as mats, carpets, and floors, it is possible to not replace with a new wet wiping sheet during wiping or to reduce the number of replacements. The ratio of "fibers with thinner fiber diameters" and "fibers with thicker fiber diameters" only needs to be within the range that produces a difference in capillary pressure, and can be appropriately set according to the purpose and usage of the wiping sheet, and is not a general concept.

<Method of Measuring Fiber Ratio>

Use a scanning electron microscope to zoom in to a magnification of 330 times, measure the number of fibers with a thicker fiber diameter and fibers with a thinner fiber diameter in the field of view of 290μm×380μm, and derive the respective ratios. As described above, fibers with a fiber diameter of 9 μm or less are regarded as fibers with a smaller fiber diameter, and fibers with a fiber diameter of 10 μm or more are regarded as fibers with a larger fiber diameter. The measurement is performed in the same manner for 20 arbitrary positions on the sheet surface, and the average value is taken as the ratio of each fiber in the first surface and the second surface.

As we all know, the capillary pressure Pc is based on the following relationship.

The capillary pressure Pc derived from the above formula is a value obtained by using the summary statistics derived from the measurement of the non-woven fabric. Here, Pc is the capillary pressure (N/m ² ) of the non-woven fabric, γ _L is the surface tension of the liquid (N/m), θ is the contact angle between the fiber and the liquid (rad), and r is the fiber diameter (m). k is a correction coefficient that takes into account factors such as the ratio of voids per unit volume of the non-woven fabric. By calibrating with this correction coefficient, the capillary pressure can be obtained more accurately.

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 set as the average value obtained by measuring 10 times in an automatic surface tensiometer based on the plate method such as DY-200 manufactured by Kyowa Interface Science Co., Ltd. under an environment of 20°C and 65% R.H. The fiber diameter system is based on observation with a scanning electron microscope, at an observation magnification of 350 times, 30 fibers are measured per observation, and the above measurement is carried out at a total of 5 locations randomly, and the average value obtained by measuring a total of 150 fiber diameters . The contact angle between the fiber and the liquid is identified by Fourier Transform infrared spectroscopy (FTIR) to identify the constituent fibers of the non-woven fabric, and the contact angle on the resin plate of the same composition is measured. Specifically, using a fully automatic contact angle meter such as DMo-901 manufactured by Kyowa Interface Science Co., Ltd., the contact angle at 3 seconds after 1 μl was dropped on the plate was measured at 5 places, and the average value was set. Furthermore, when there are more than one fiber materials, the contact angle of each material is measured in the same way as the value when calculating Pc, which is the value obtained by weighting the contact angle based on the surface area ratio of each fiber component Set as θ in the formula.

From the above formula, it is clear that the smaller the fiber diameter (thin), the higher the capillary pressure becomes. In the present invention, the fiber diameter is reduced to increase the capillary pressure on the first surface side. If the wiping liquid contained in the fiber assembly on the first side becomes less or disappears, the wiping liquid carried by the fiber assembly on the second side is introduced to the fiber assembly on the first side due to the difference in capillary pressure In the body. Thereby, an appropriate amount of wiping liquid is supplied to the fiber assembly on the first surface side, and the first surface side is always in a state where there is an amount of wiping liquid suitable for wiping.

In addition, in the wet wiping sheet surface including voids, the area ratio of fibers with finer fiber diameters in the first surface is preferably 40% or more and 99% or less, more preferably 45% or more and 95% or less, more preferably 50% or more and 90% or less. On the other hand, it is preferable that the area ratio of the fibers with the finer fiber diameters in the second surface is 0% or more and 55% or less. The area occupied by the fibers with the finer fiber diameter in the first surface is obtained by measuring the area occupied by the fibers with the finer fiber diameter based on, for example, an image or a photograph obtained by shooting the first surface. Hereinafter, the area occupied by each fiber can be obtained 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. Furthermore, in the case of %, it becomes 100 times the value obtained by dividing.

Here, for example, the remaining 1% of 99% of the upper limit of the above-mentioned area ratio of 40% or more and 99% or less is a void. This gap is necessary for the wiping liquid to be released to the first surface. By adjusting the ratio of the gaps, even when wiping hard, the amount of wiping liquid released for wiping off the dirt on the surface to be wiped can be suppressed to a necessary amount. In addition, by setting the area ratio of the fibers with a smaller fiber diameter in the second surface in the above-mentioned manner, as a result, the number of voids increases and the amount of the wiping liquid to be carried increases. Since the area ratio of the fibers with the finer fiber diameters in the first surface is above the above lower limit, an appropriate amount of wiping liquid is released, so that no more than the necessary amount of wiping liquid is released. Therefore, the area that can be wiped becomes larger.

In the present invention, in the surface parallel to the first surface, it is preferable that the area ratio of the fiber with a smaller fiber diameter is toward the thickness direction of the opposite surface side of the first surface, stepwise, curvilinear, or other The form of such combinations is reduced. In particular, by setting the area ratio of fibers with thinner fiber diameters to a range of 50% or more and 100% or less of the thickness of the wet wiping sheet from the second surface to 50% or more and 100% or less, It can increase the loading capacity of the wiping liquid. Here, the area ratio of the fiber with the finer fiber diameter is set to be the above thickness in the range of 50% or more and 100% or less The ratio is preferably 1% or more and 90% or less, more preferably 5% or more and 70% or less, and still more preferably 7% or more and 50% or less. Furthermore, by setting the ratio of the preferable thickness as described above, it is possible to release the necessary amount of the wiping liquid that is released by wiping off the dirt on the surface to be wiped.

Here, in order to obtain information on the inside of the wet wiping sheet, a co-focus laser microscope can be used. By using a confocal laser microscope, a map of the inside of 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 non-destructively.

In the present invention, at least two layers including a liquid retaining layer and a liquid releasing layer supporting a wiping liquid are included, and the liquid releasing layer includes the first surface. Especially in order to carry more wiping liquid, from the second side as described above, for the wet wiping sheet thickness of 50% or more and 100% or less, set the area ratio of the fiber with the thinner fiber diameter. It is 1% or more and 100% or less. Thereby, it is possible to form a liquid-retaining layer that supports a large amount of wiping liquid. On the other hand, the liquid releasing layer includes parts other than the liquid retaining layer on the first surface.

In the present invention, regarding the weight per unit area of the fiber, the first surface side 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 still more preferably 10 g/m ² or more and 30 g/m ² or less. On the other hand, the second surface side 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 still more preferably 20 g/m ² or more and 25 g/m 2 m ² or less.

In the present invention, it is particularly preferable that fibers with different fiber diameters are intertwined without being thermally fused with each other. As a result, compared with the case of thermal fusion, the space between the fibers increases and the amount of wiping liquid carried increases.

The wet wiping sheet of the present invention releases the wiping liquid from the first surface to the wiping target surface by wiping once, that is, wiping the wiping target surface once. The amount of wiping liquid released per wiping is preferably 0.5 g/stack of mat or more, more preferably 0.7 g/stack of mat or more, and even more preferably 1.0 g/stack of mat or more. Regarding the upper limit of the released amount, it is actually 8 g/stack of mat or less, preferably 7 g/stack of mat or less, and more preferably 6 g/stack of mat or less. When the release amount is equal to or higher than the lower limit value, it can be wiped off sufficiently, and as the amount is equal to or lower than the upper limit value, it is less likely that the wiping liquid remains on the first surface. Here, the size of the stacked mat is 1820mm×910mm, and the stacked mat area is 1.6552m ² .

Fig. 6 is a graph showing the results obtained by investigating the amount of liquid released per stack when wiping the floor one by one. By measuring the amount (g) of liquid released per one stack as described above and plotting it, the behavior of liquid release can be predicted.

The measurement conditions of the release behavior are the wiping load (load W) 0.16 kN/m ² and the wiping speed (speed V) 1 m/s. In the present invention, the release amount per one stack is preferably 1 g or more, and the upper limit is preferably 10 g or less.

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

In this way, it is possible to achieve the target liquid release amount of more than 1g/stack for each wipe, and it can last for more than the 6th stack.

<Wipe liquid>

The wiping liquid is generally the wiping liquid used in the wet wiping sheet.

That is, the wiping liquid may be water alone or an aqueous solution containing a surfactant, preferably an aqueous solution containing a surfactant.

The surfactant may be any one of a nonionic surfactant, an amphoteric surfactant, a cationic surfactant, or an anionic surfactant. For example, alkyl benzene sulfonic acid, etc. can be used Nonionic surfactants such as anionic surfactants or polyoxyethylene alkyl ethers.

Additives can also be contained in the wiping liquid. Examples of additives include polymers of acrylic acid, methacrylic acid, or maleic acid or their salts, and copolymers of maleic acid and other vinyl monomers or their salts, etc., for the purpose of improving the flushing effect. In addition, water-soluble organic solvents such as bactericides, fragrances, fragrances, deodorants, abrasive particles, pH adjusters, alcohols, and the like can be cited.

Regarding the content of the surfactant and the above-mentioned additives, they are generally used in the range used in wet wiping sheets.

<<Manufacturing method of wet wiping sheet>>

In the wet wiping sheet of the present invention, at least two kinds of fibers with different fiber diameters are intertwined. The manufacturing step of the present invention includes a spunlace step, which blows water to at least two layers of fiber aggregates that are different in fiber diameters from the fiber aggregates of the fiber aggregates of each other to make a fiber aggregate Part of it enters another fiber assembly. In particular, by using the spunlace method to make a part of one fiber assembly enter another fiber assembly, the fusion between fibers such as the entanglement method using hot air is not substantially generated.

In the present invention, the blowing of the water stream is preferably performed at least from the layer side of the fiber assembly including fibers with a thinner fiber diameter of the above-mentioned laminate. In this case, it is also possible to arrange a non-woven fabric or net different from the layer on the layer containing the fiber assembly of the fiber with a thinner fiber diameter, and blow water from the non-woven or net side of the arrangement, which Then peel off the configured non-woven fabric or mesh. This aspect is a better aspect in the present invention. In addition, a further preferred aspect is that after the disposition of the non-woven fabric or net is peeled off, water is blown from the layer of the fiber assembly containing the fibers with the thinner fiber diameter.

The fiber diameters of the fiber with a thinner fiber diameter and the fiber with a thicker fiber diameter are the same as the above, and the fiber length of the fiber with a thinner fiber diameter and the fiber with a thicker fiber diameter are also as described above.

The weight per unit area of the fiber assembly including fibers with finer fiber diameters 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 It is preferably 10 g/m ² or more and 30 g/m ² or less. The weight per unit area of the fiber assembly including fibers with relatively thick fiber diameters 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 It is preferably 20 g/m ² or more and 25 g/m ² or less.

Furthermore, when a non-woven fabric different from that of the layer is arranged on a layer containing a fiber assembly of fibers with finer fiber diameters, the weight per unit area of the non-woven fabric is preferably 11 g/m ² or more and 150 g/m ² or less, It is more preferably 20 g/m ² or more and 80 g/m ² or less, and still more preferably 30 g/m ² or more and 75 g/m ² or less. Here, in the present invention, the non-woven fabric may also be a fiber assembly including fibers with a thicker fiber diameter under the layer including fibers with a thinner fiber diameter, which is preferable in the present invention State.

In the present invention, with regard to the applied water needling method, the entanglement energy applied to the laminate of the fiber assembly can be controlled by the number of water spray nozzles, the water pressure, the line speed, and other conditions.

Here, a non-woven fabric or net that is different from the layer is placed on the layer containing the fiber assembly of fibers with finer fiber diameters, and placed on the conveyor belt composed of perforated nets, and the non-woven fabric is self-arranged on the conveyor belt Or blow the water flow on the side of the net. After that, after peeling off the arranged non-woven fabric or net, the water flow is blown from the layer side of the fiber assembly containing fibers with finer fiber diameters. In this case, the number of spray nozzles, water pressure, linear velocity and other conditions for the second time can also be changed to the first time.

In the present invention, it is preferable to place the laminate containing the fiber assembly on the perforated mesh shell, and to suck from the side opposite to the side where the laminate containing the fiber assembly is placed.

The perforated mesh shell can be flat or circular, but a circular shape is efficient and therefore preferred.

In the present invention, the fiber can also be fibrillated when the spunlace method is applied, but the fiber diameter of the obtained fiber with a finer fiber diameter is preferably 0.1 μm or more and 9 μm or less.

In the present invention, after the hydroentangling step, the fiber assembly on the second surface side where the ratio of fibers with a larger fiber diameter is larger is supported with a wiping liquid. The content of the wiping liquid (loading amount of the fiber assembly) is preferably 1 g/sheet or more, more preferably 10 g/sheet or more, and still more preferably 12 g/sheet or more. The upper limit of the content of the wiping liquid is actually 40 g/sheet or less, preferably 30 g/sheet or less, and more preferably 20 g/sheet or less.

Regarding the method containing the wiping liquid, it can be listed: spraying liquid in a roll-to-roll production line; passing a liquid storage tank under roll-to-roll; pouring liquid after cutting and lamination, etc., preferably roll-to-roll The method of spraying liquid in the roll production line.

<Method for manufacturing fiber assembly including fibers with finer fiber diameters in fiber assembly>

A fiber assembly containing fibers with a finer fiber diameter may also be a commercially available fiber assembly containing fibers with a finer fiber diameter. In the present invention, it is preferably by a melt-type electrospinning method (melt electrospinning method) Make it.

The device for implementing the melt-type electrospinning method is not particularly limited as long as it can realize the melt-type electrospinning method. As this device, a heat-melting module for heating and melting a thermoplastic resin is provided, and an electrospinning module is provided for applying a voltage to the heated-melted thermoplastic resin to extend the thermoplastic resin fibrously. Furthermore, the device is provided with a capturing component for capturing the extended ultrafine fibers into the collector by electric attraction.

The heating method for heating and melting the component may be any method as long as it is a method performed by a melt-type electrospinning method.

In addition, the electrospinning component may be any component as long as it is a component performed by a melt-type electrospinning method. Furthermore, the heating part preferably has the temperature control and the extension The stretched fiber passes through the heating space above 30mm.

The capturing component can also be composed of a collector for capturing ultrafine fibers.

The obtained spun yarn is collected in a collector, layered and expanded in a sheet form (net-like) to produce a non-woven fiber assembly.

In the present invention, there is no weaving step, and there is no need for a heat-shrinkable mesh. Compared with the manufacturing method such as the step of heat-shrinking the high-shrinkage fiber of the non-woven fabric and the step of applying the spunlace method, the number of steps is less It can be mass-produced simply and inexpensively.

<<Use of Wet Wipe Sheet>>

The wet wiping sheet of the present invention can be provided with various functions by the structure of voids or layers, the control of wettability, and the like. Therefore, the wet wiping sheet of the present invention can be used, for example, in buildings such as floor and wall surfaces; sliding doors and windows such as cabinets, window glass, mirrors, doors, door handles, etc.; furniture such as cushions, carpets, desks, dining tables, and kitchens, toilets, etc. Wipe the fixed device and so on. In addition, it can be used for cleaning wipes, and can also be used for cleaning the face, body, etc., or sanitary products, civil engineering, packaging, etc.

Here, Figures 5 to 7 show the representative wet wiping sheet of the present invention manufactured in the above-mentioned manner. Specifically, a fiber assembly including fibers with a thinner fiber diameter is formed by a melt-type electrospinning method. The fiber is polypropylene, and the obtained spinning diameter, that is, the fiber diameter is 0.6 to 3 μm. As an aggregate of fibers with a relatively thick fiber diameter, a non-woven fabric of polyethylene terephthalate, rayon, and acrylic with a fiber diameter of 10 to 18 μm is used.

The weight per unit area of the non-woven fabric containing the aggregate of fibers with a relatively thick fiber diameter is 65 g/m ² , and the weight per unit area of the fabric aggregate containing the fibers with the thinner fiber diameter is 55 g/m ² . Between two non-woven fabrics containing an aggregate of fibers with a relatively thick fiber diameter, a high-pressure jet of water is blown again from the fiber assembly side containing fibers with a relatively thin fiber diameter, so that a part of the fiber assembly enters the other fiber In the collection. The weight per unit area of the fibers in the entire sheet obtained was 120 g/m ² .

The photograph obtained by observing the section of the sheet with a scanning electron microscope is shown in FIG. 5.

The upper side of the figure becomes the first surface (wiping surface).

Thereafter, the wiping liquid was injected from the side of the non-woven fabric containing the aggregate of fibers with a relatively thick fiber diameter. As a result, the content of the wiping liquid reached 7.8 g/sheet. Using the wet wiping sheet manufactured in this way, the relationship between the amount of liquid released per one stack (g) and the wiping area (stack) is plotted and shown in Figure 6.

As shown in Figure 6, the amount of liquid released per one stack up to the seventh stack is 1g or more. In addition, the release rate of the 14th stack was 81%. Furthermore, the impregnation rate is calculated by the method of impregnating liquid mass/fiber mass×100, which is 380%.

The friction resistance is 1.6N, which is less than that of a sheet with a fiber diameter of 0.3 to 3 μm on the entire surface, but it is roughly the same as a microfiber sheet with a fiber diameter of 10 to 18 μm on the entire surface.

Here, the friction resistance is obtained by installing the wiping head in a tension pressure gauge, scanning so that the angle of the tension pressure gauge becomes parallel to the wiping plane, measuring the maximum stress, and drawing it.

Fig. 7 is a photograph of the first side after wiping with the above-mentioned wet wiping sheet. It is observed that the unevenness of the uneven part is filled with dirt. In FIG. 7, according to the above-mentioned photo observation, it is suggested that the dirt that has not been cleaned before is also removed.

As described above, with the present invention, it is possible to provide a wet wiping sheet that removes dirt by wiping lightly, and does not need to be replaced even if the wiping area is large, or the number of replacements can be reduced. Furthermore, it is possible to provide a method for manufacturing a wet wiping sheet that can be easily and mass-produced.

Regarding the above-mentioned embodiments, including the above-mentioned wet wiping sheet, the present invention discloses The following wet wiping sheet and its manufacturing method.

(1) A wet wiping sheet, which has a first side and a second side opposite to the first side, and includes at least two types of fibers with different fiber diameters, and the above-mentioned at least two types of fibers Fibers with different diameters are entangled, and the ratio of fibers with smaller fiber diameters in the fibers of the fiber assembly is more on the first surface side than on the second surface side, and the fibers of the fiber assembly have larger fiber diameters The ratio of the presence of fibers is more on the second surface side than the first surface side, and the capillary pressure of the first surface side is higher than the second surface side, and at least on the fiber assembly on the second surface side. Contains wiping liquid.

(2) The wet wiping sheet as described in (1), wherein the above-mentioned at least two kinds of fibers with different fiber diameters are entangled without being thermally fused with each other.

(3) The wet wiping sheet as described in (1) or (2), wherein on the first surface of the wet wiping sheet, there are an aggregate of fibers with a smaller fiber diameter and fibers with a larger fiber diameter.

(4) The wet wiping sheet as described in any one of (1) to (3), wherein the area ratio of fibers with finer fiber diameters in the first surface is 40% or more and 99% or less , Preferably 45% or more and 95% or less, more preferably 50% or more and 90% or less.

(5) The wet wiping sheet as described in any one of (1) to (4), wherein the fiber diameter of the fibers with different fiber diameters is 0.1μm or more and 9μm or less , Preferably 0.5 μm or more and 5 μm or less.

(6) The wet wiping sheet as described in any one of (1) to (5), wherein the fiber diameter of fibers with different fiber diameters is greater than that of 10 μm and less than 30 μm. It is preferably 15 μm or more and 25 μm or less.

(7) The wet wiping sheet as described in any one of (1) to (6), wherein fibers with different fiber diameters are fibers of the same composition as each other.

(8) The wet wiping sheet as described in any one of (1) to (6), wherein fibers with different fiber diameters are fibers with different components from each other.

(9) The wet wiping sheet as described in any one of (1) to (8), wherein the wet wiping sheet includes at least two layers of a liquid retaining layer and a liquid releasing layer supporting the wiping liquid , And the liquid releasing layer includes the above-mentioned first surface.

(10) The wet wiping sheet as described in any one of (1) to (9), wherein from the second side, the thickness of the wet wiping sheet is 50% or more and 100% or less, and the fiber The ratio of the area occupied by the finer fibers is set to 1% or more and 100% or less, and a liquid-retaining layer that supports more wiping liquid is arranged on the second surface side.

(11) The wet wiping sheet as described in any one of (1) to (10), wherein the wiping liquid is released from the first surface to the surface to be wiped by wiping the surface to be wiped once. The amount is 0.5g/stacked mat or more, preferably 0.7g/stacked mat or more, more preferably 1.0g/stacked mat or more (the area of the stacked mat is 1.6552m ² ).

(12) The wet wiping sheet as described in any one of (1) to (11), wherein the wiping liquid is released from the first surface to the wiping surface by wiping the wiping target surface once. The amount is 8 g/stacked mat or less, preferably 7g/stacked mat or less, and more preferably 6g/stacked mat or less (the area of the stacked mat is 1.6552m ² ).

(13) The wet wiping sheet as described in any one of (1) to (12), wherein the amount of wiping liquid carried is the amount carried by the fiber assembly on the side opposite to the first side many.

(14) A method for manufacturing a wet wiping sheet, which is the method for manufacturing a wet wiping sheet as described in any one of (1) to (13), the manufacturing method comprising: A spunlace step, which blows a water stream to a laminate comprising at least two layers of fiber aggregates with different fiber diameters of the fibers constituting the fiber aggregates of the mutual layers, so that a part of one fiber aggregate enters the other fiber aggregate , And blowing of the water flow is performed at least from the layer side of the fiber assembly including fibers with finer fiber diameters of the laminate.

(15) The method for producing a wet wiping sheet as described in (14), wherein the above-mentioned spunlace step is to arrange a non-woven fabric or mesh that is different from the layer on a layer of fiber aggregates containing fibers with finer diameters The water flow is blown from the side of the non-woven fabric or net that is placed, and after the water flow is blown, the non-woven fabric or web that is placed is peeled off.

(16) The method for producing a wet wiping sheet as described in (15), wherein after the non-woven fabric or net is peeled off, it is then removed from the layer side of the fiber assembly containing fibers with finer fiber diameters of the laminate Perform water blowing.

(17) The method for producing a wet wiping sheet as described in any one of (14) to (16), wherein the above-mentioned fiber assembly is formed by a melt-type electrospinning method and includes fibers with a finer fiber diameter The fiber assembly.

(18) The method for producing a wet wiping sheet as described in any one of (14) to (17), wherein a laminate containing a fiber assembly is placed on a perforated net shell, and the fiber assembly is freely placed The side of the laminated body is sucked on the opposite side.

(19) The method for producing a wet wiping sheet as described in any one of (14) to (18), wherein the fibers are fibrillated by a hydroentanglement method.

The present invention has been described together with its embodiments and examples. However, as long as the inventors do not specify otherwise, the present invention is not limited to any details of the description, and it is considered that it should not deviate from the scope of the attached patent application. Explain the spirit and scope of the invention in a wide range release.

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 in Japan on August 9, 2017. The contents are referred to here and incorporated into this text as part of the description of this specification.

Claims (17)

A wet wiping sheet, which has a first side and a second side opposite to the first side, and includes at least two types of fibers with different fiber diameters, and the above-mentioned at least two types of fibers with different fiber diameters Intertwined, the ratio of the fibers with the smaller fiber diameters in the fibers of the fiber assembly is more on the first surface side than the second surface side, and the fibers with the larger fiber diameters in the fibers of the fiber assembly exist The ratio is more on the second surface side than the first surface side, and the capillary pressure of the first surface side is higher than the second surface side, and at least the fiber assembly on the second surface side carries the wiping liquid, And by wiping the wiping target surface once, the amount of the wiping liquid released from the first surface to the wiping target surface is 0.5 g/stack of mats or more (wherein, the area of the mat is 1.6552 m ² ). Such as the wet wiping sheet of claim 1, wherein at least two kinds of fibers with different fiber diameters are intertwined without being thermally fused with each other. The wet wiping sheet of claim 1 or 2, wherein the first surface of the wet wiping sheet includes an aggregate of the fibers with the smaller fiber diameter and the fibers with the larger fiber diameter. The wet wiping sheet of claim 1 or 2, wherein the area ratio of the fibers with the finer fiber diameters in the first side is 40% or more and 99% or less. Such as the wet wiping sheet of claim 1 or 2, in which the fibers of the above-mentioned fibers with different fiber diameters Among the diameters, the fiber diameter of the above-mentioned smaller fiber diameter is 0.1 μm or more and 9 μm or less. The wet wiping sheet of claim 1 or 2, wherein among the fiber diameters of the fibers with different fiber diameters, the fiber diameter of the fibers with the thicker fiber diameter is 10 μm or more and 30 μm or less. The wet wiping sheet of claim 1 or 2, wherein the fibers with different fiber diameters are fibers of the same composition as each other. The wet wiping sheet of claim 1 or 2, wherein the fibers with different fiber diameters are fibers with different components from each other. The wet wiping sheet of claim 1 or 2, wherein the wet wiping sheet includes at least two layers of a liquid retaining layer and a liquid releasing layer supporting the wiping liquid, and the liquid releasing layer includes the first noodle. Such as the wet wiping sheet of claim 1 or 2, wherein from the second side, the area occupied by the fibers with the thinner fiber diameter is 50% or more and 100% or less of the thickness of the wet wiping sheet The ratio is set to 1% or more and 100% or less, and a liquid-retaining layer that supports a large amount of the wiping liquid is arranged on the second surface side. Such as the wet wiping sheet of claim 1 or 2, wherein the amount of the wiping liquid released from the first surface to the wiping surface by wiping the wiping target surface once is 8g/stack The seating area is 1.6552m ² ). The wet wiping sheet of claim 1 or 2, wherein the amount of the wiping liquid carried is larger than the amount carried by the fiber assembly on the side opposite to the first surface. A method for manufacturing a wet wiping sheet, which is the method for manufacturing a wet wiping sheet according to any one of claims 1 to 12. The laminated body of at least 2 layers of fiber assembly with different fiber diameters of the fibers of the assembly blows water, so that a part of one fiber assembly enters the other fiber assembly, at least from the laminated body containing the thinner fiber diameter The layer side of the fiber assembly of the fiber is blown by the above-mentioned water flow, and the laminated body containing the above-mentioned fiber assembly is placed on the perforated net shell, and suction is performed from the side opposite to the side where the laminated body containing the above-mentioned fiber assembly is placed. . The method for manufacturing a wet wiping sheet according to claim 13, wherein the above-mentioned spunlace step is to arrange a non-woven fabric or mesh that is different from the layer on a fiber assembly layer containing fibers with finer fiber diameters. The side of the non-woven fabric or net that is arranged is blown by the water flow, and after the water flow is blown, the non-woven fabric or the net that is arranged is peeled off. The method for manufacturing a wet wiping sheet according to claim 14, wherein after the non-woven fabric or net is peeled off, water is blown from the layer side of the fiber assembly including fibers with finer fiber diameters of the laminate. The method for manufacturing a wet wiping sheet according to claim 13, wherein a fiber assembly including fibers with a thinner fiber diameter in the above-mentioned fiber assembly is formed by a melt-type electrospinning method. The method for manufacturing a wet wiping sheet according to claim 13, wherein the above-mentioned fiber is fibrillated by a spunlace method.

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