Method of manufacturing a paper towel and method of manufacturing a paper towel product

Abstract

Provided is a method for manufacturing a paper towel having 3 or 4 layers, which reduces the tacky feeling of the outer surface while ensuring the necessary softness. In the manufacture of a paper towel composed of a laminated sheet having 3 or 4 layers laminated, each layer contains a water-based moisturizer that exhibits hygroscopicity, the method for manufacturing the paper towel comprising: causing each layer to have a difference in the size of the arithmetic mean height Sa based on ISO 25178 between both faces thereof; applying the moisturizer to the layers; applying the moisturizer to the outer side face of each layer on the outer side of the laminated sheet in a state in which the arithmetic mean height Sa is smaller on the face of the outer side face; folding the laminated sheet after the application of the moisturizer to the layers is completed; and then storing in the storage body in the folded state.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for manufacturing a paper towel and a method for manufacturing a paper towel product. BACKGROUND

[0002] The mainstream of paper towels is 2 layers, but in recent years, the demand for paper towels of multiple layers such as 3 layers, 4 layers, and the like, which have a sense of thickness, is also increasing.

[0003] Such paper towels of multiple layers are mostly products of the high-grade type with high product prices, and paper towels of such product groups particularly require "fluffy fluffiness" corresponding to the number of layers, "smoothness of the surface", and "softness".

[0004] Furthermore, in the case of a multiple layer structure, if the weight per unit area of each layer is increased, the paper thickness can be easily thickened by the sum of the layers, and thus "fluffy fluffiness" can be exhibited.

[0005] However, in the case where the weight per unit area of each layer is increased as such, it is important to exhibit "fluffy fluffiness" on the basis of also ensuring softness, smooth quality.

[0006] With regard to paper towels, various paper towels are sold on the market, and in one field thereof, there are paper towels containing water-based moisturizing agents, which are called moisturizing paper towels or lotion paper towels.

[0007] In order to meet people who frequently use paper towels to blow their noses due to hay fever, colds, and the like, the conventional moisturizing paper towels and lotion paper towels are manufactured to have soft and smooth quality that does not cause redness or pain even if the skin is repeatedly used.

[0008] The use of paper towels differs depending on the country. This is considered to be caused by differences in lifestyle or cultural forms.

[0009] Moisturizing paper towels and lotion paper towels in Japan are mainly 2-layer paper towels, but for example, in China, 3-layer paper towels are mainstream.

[0010] Prior Art Documents

[0011] Patent Documents

[0012] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-171254 SUMMARY

[0013] Problems to be Solved by the Invention

[0014] In the conventional moisturizing paper towels or lotion paper towels having 3 layers stacked or in the manufacture thereof, a moisturizing agent is applied only to the two outer sheet materials, and the intermediate layer sheet material is not coated with a moisturizing agent.

[0015] In the conventional moisturizing paper towel or cosmetic water paper towel, in order to make the user feel softness at the time of use, it is necessary to apply a certain amount of moisturizer.

[0016] However, on the other hand, since the application amount of the moisturizer is large, a sticky feeling is generated on the outer surface of the outer sheet, and thus it is not preferable.

[0017] Therefore, an object of the present application is to provide a manufacturing method of a 3-layer or 4-layer paper towel and a manufacturing method of a paper towel product, which reduce a sticky feeling on the outer surface while ensuring necessary softness.

[0018] Means for solving the problem

[0019] The manufacturing method of the paper towel of the present application, which solves the above problem, is characterized in that,

[0020] In manufacturing a paper towel composed of a laminated sheet in which 3 layers or 4 layers are laminated,

[0021] Each layer contains a water-based moisturizer that exhibits hygroscopicity,

[0022] The manufacturing method of the paper towel includes:

[0023] Each layer has a difference in the size of the arithmetic mean height Sa based on ISO 25178 between both faces thereof;

[0024] The moisturizer is applied to the layers;

[0025] The moisturizer is applied to the outer side face of each layer on the outer side of the laminated sheet, which is the face having a small arithmetic mean height Sa; and

[0026] The laminated sheet after the application of the moisturizer to the layers is folded.

[0027] Further, in the manufacturing method of the paper towel product, the paper towel product is obtained by housing a paper towel composed of a laminated sheet in which 3 layers or 4 layers are laminated in a housing body, and is characterized in that,

[0028] Each layer contains a water-based moisturizer that exhibits hygroscopicity,

[0029] The manufacturing method of the paper towel product includes:

[0030] Each layer has a difference in the size of the arithmetic mean height Sa based on ISO 25178 between both faces thereof;

[0031] The moisturizer is applied to the layers by a flexographic printing method;

[0032] Applying the moisturizing agent to the outer side surface of each layer located outside the laminated sheet in a state where the outer side surface of each layer has the smallest arithmetic mean height Sa;

[0033] folding the laminated sheet after application of the moisturizing agent to each layer; and

[0034] Then, the container is stored in the storage body in a folded state.

[0035] Effects of the Invention

[0036] According to the present invention, a method for producing a three-layer or four-layer paper towel and a method for producing a paper towel product can be obtained in which the stickiness of the outer surface is reduced while ensuring the necessary softness. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic cross-sectional view of a three-layer embodiment.

[0038] Figure 2 This is a schematic cross-sectional view of a four-layer embodiment.

[0039] Figure 3 This is a schematic cross-sectional view of a conventional three-layer embodiment.

[0040] Figure 4 This is a schematic cross-sectional view of a conventionally envisioned four-layer embodiment.

[0041] Figure 5 This is a photo of an example of a surface where a drug solution has been applied.

[0042] Figure 6 This is a photo of an example of a surface where a drug solution has been applied.

[0043] Figure 7 This is a schematic diagram of an example of obtaining a continuous sheet at one time.

[0044] Figure 8 This is a schematic diagram of a three-layer coating example.

[0045] Figure 9 This is a schematic diagram of another coating example of three layers.

[0046] Figure 10 This is a schematic diagram of a four-layer coating example.

[0047] Figure 11 This is a schematic diagram of another coating example of three layers.

[0048] Figure 12 This is a schematic diagram of another coating example of 4 layers.

[0049] Figure 13 This is a schematic diagram of another coating example of 4 layers.

[0050] Figure 14 is a schematic view of a spray coating apparatus example.

[0051] Figure 15 is a schematic view of another coating example of 3 layers based on the spray coating apparatus example.

[0052] Figure 16 is a schematic view of another coating example of 3 layers based on the spray coating apparatus example.

[0053] Figure 17 is an explanatory view of a folding method.

[0054] Figure 18 is a schematic perspective view of a storage example for a storage case.

[0055] Figure 19 is a cross-sectional view of a storage example for a storage case. DETAILED DESCRIPTION

[0056] Hereinafter, the present application will be further explained while showing an embodiment of the present application.

[0057] An embodiment of a paper towel in which 3 layers or 4 layers are laminated is explained.

[0058] Since it is not 2 layers but 3 layers or 4 layers, it brings about a "fluffy fluffy feeling".

[0059] Figure 1 An embodiment of 3 layers (1R, 2R, 3R) is shown, Figure 2 An embodiment of 4 layers (1R, 2R, 3R, 4R) is shown. Figure 3 An embodiment of a conventional 3 layers (1R, 2R, 3R) is shown, Figure 4 An embodiment of a conventional 4 layers (1R, 2R, 3R, 4R) is shown.

[0060] Further, a coating surface F and a non-coating surface W of a moisturizer (hereinafter, also referred to as "liquid medicine", the meaning is the same) are shown. Since there is a not small moisturizer containing concentration gradient in the thickness direction from the coating surface F toward the non-coating surface W, the concentration gradient is illustrated in color tone.

[0061] Each layer is applied with a water-based moisturizer that exhibits hygroscopicity, and thus contains a moisturizer. As the water-based moisturizer that exhibits hygroscopicity, a moisturizer in which a polyhydric alcohol is a main component, particularly a moisturizer in which glycerin is a main component (i.e., containing more than 50 mass% of glycerin, preferably containing 70 mass% or more of glycerin) can be used. Glycerin exhibits hygroscopicity in addition to moisturizing property.

[0062] In order to improve the surface properties, particularly the smoothness, liquid paraffin can be contained. In addition, 1,3-propanediol can be contained in an amount of 6.1% by mass or more and 12.6% by mass or less, as needed.

[0063] In the paper towel, in addition to the moisturizing agent such as glycerin, a known auxiliary agent can be contained. As examples of the auxiliary agent, a moisturizing auxiliary component such as sorbitol, a hydrophilic polymer gelling agent for improving the moisture retention in the paper towel, a surfactant or a softness improving agent, an oily component such as the above-mentioned liquid paraffin which assists in the appearance of smoothness, and other emulsifiers, preservatives, antifoaming agents, and the like for improving the stabilization and application properties of the moisturizing agent can be mentioned. In addition, the compounding amount of the components such as the moisturizing auxiliary component and the hydrophilic polymer gelling agent for improving the moisture retention is set to an extent which does not excessively affect the "fluffy softness", the "softness", and the "smoothness of the surface". Specifically, it can be set to 1.0% by mass or less, preferably 0.6% by mass or less, and more preferably 0.5% by mass or less.

[0064] The unit area weight of the 1 layer of the paper towel of the present embodiment is preferably 15.0 to 22.5 g / m 2 , and particularly preferably 15.5 to 20.5 g / m 2 . If the unit area weight of each layer is within this range, the "softness" and the "fluffy softness" are significantly exhibited.

[0065] Since there is a tendency that the paper becomes hard when the unit area weight is high and becomes soft when the unit area weight is low, it is considered that the unit area weight greatly affects the "softness". If the number of layers is "3 or 4" at this unit area weight, the "fluffy softness" can be significantly imparted. In addition, the unit area weight is a value measured based on JIS P 8124 (1998).

[0066] The above-mentioned water-based moisturizing agent is contained in each layer at substantially the same amount. That is, when the moisturizing agent (lotion) content at the dry standard of the product is set to 100, the moisturizing agent (lotion) content at the dry standard of each layer is in the range of 92.0 to 108.0. It is desirable that the moisturizing agent (lotion) content at the dry standard of each layer is in the range of 95.0 to 104.0.

[0067] As described above, in the conventional moisturizing paper towel (also referred to as a lotion paper towel), in order to make the user feel the softness at the time of use, it is necessary to apply a certain amount of the moisturizing agent. Therefore, in order not to cause the paper towel to be excessively soft, it is necessary to control the amount of the moisturizing agent to be applied to the paper towel. Figure 3 and Figure 4 In the conventional embodiment shown in Figs. 1 and 2, the intermediate layer (2R, Figure 3 is 2R, Figure 4In the case where the moisturizer is applied to the outer layer sheet, the amount of the moisturizer applied to the outer layer sheet tends to increase, and thus the outer surface of the outer layer sheet tends to feel sticky.

[0068] On the other hand, in the embodiment, the moisturizer is applied to the intermediate layer (intermediate sheet layer) as well as the outer layer.

[0069] The structure is advantageous in that the intermediate layer (intermediate sheet layer) is made to contain the moisturizer, and thus the entire stacked sheet becomes soft. Figure 1 The intermediate layer (intermediate sheet layer) is made to contain the moisturizer, Figure 2 The intermediate layer (intermediate sheet layer) is made to contain the moisturizer,

[0070] As a result, the amount of the moisturizer contained in the outer layer sheet can be reduced, and thus the sticky feeling on the outer surface of the outer layer sheet (the exposed surface of the stacked sheet) caused by the moisturizer can be eliminated or suppressed.

[0071] In addition, when the moisturizer (liquid medicine) content ratio under the dry standard of the product is set to 100, as long as the dry moisturizer (liquid medicine) content ratio under the dry standard of each layer is within the above range, the advantage can be exhibited substantially regardless of the weight per unit area of each layer and the content of the moisturizer in each layer.

[0072] In order to make the intermediate layer (intermediate sheet layer) contain the moisturizer as well, the moisturizer can be applied directly to the intermediate layer in addition to the outer layer.

[0073] For example, in the case where the moisturizer is applied to the outer layer sheet of the stacked sheet, the moisturizer applied to the outer layer sheet moves in such a manner that it penetrates and diffuses from the applied surface to the entire body over time. However, when external pressure such as calendering is applied to the stacked sheet, a part of the moisturizer applied to the outer layer sheet of the stacked sheet is transferred to the adjacent sheet. However, in the case where the amount of the moisturizer applied is small, the amount of the transferred moisturizer to the adjacent sheet is small.

[0074] On the other hand, in the case where the amount of the moisturizer applied is large, although the amount of the transferred moisturizer to the adjacent sheet increases, the transfer is limited, and a clear difference in the content of the moisturizer is exhibited between the outer layer sheet to which the moisturizer is applied and the adjacent sheet.

[0075] Therefore, in order to make the intermediate layer (intermediate sheet layer) contain the moisturizer necessary to ensure softness as well, the moisturizer needs to be applied directly to the intermediate layer in addition to the outer layer.

[0076] On the contrary, if a large amount of the moisturizer is applied to the outer sheet in order to ensure softness by transferring the moisturizer to the intermediate layer, a large amount of the moisturizer remains on the outer surface (exposed surface) of the outer sheet, resulting in a tacky feeling.

[0077] However, by also applying the moisturizer directly to the intermediate layer (intermediate sheet), the amount of the moisturizer applied to the outer surface (exposed surface) of the outer sheet can be reduced, and thus the generation of a tacky feeling can be eliminated or suppressed.

[0078] In order to impart softness to the paper towel, the ply base paper is usually subjected to creping processing. In the embodiments, creping processing is also preferably performed.

[0079] The number of creases is preferably 38 to 54 roots / cm.

[0080] The number of creases (roots / cm) measured by one-shot 3D can be expressed by a value obtained by counting the number of peaks of the peak-valley shape in the MD direction over a length of 1.0 to 2.0 cm in the MD direction and dividing the measured length in the MD direction.

[0081] When the shape is measured by one-shot 3D and the height profile on the X-Y plane is shown on the screen, the height of the paper towel surface is expressed by the color tone. The shape of the creases in the height direction can be confirmed from the measured profile curve. Here, since the creases are formed with valleys and peaks in a direction perpendicular to the MD direction by 90 degrees, it refers to a value obtained by counting the number of peaks of the peak-valley shape in the MD direction over a length of 1.0 to 2.0 cm and dividing the measured length in the MD direction. For one sample, the average of the measured values of five points is used as the value.

[0082] The sharpness of the peak top of the concave-convex "arithmetic mean curvature of the peak top SPC" is preferably 2.8 to 3.5 (1 / mm) (the larger the value, the sharper the fine convex of the surface).

[0083] By this creping processing, the surface roughness is different between one face and the other face of the ply base paper.

[0084] In the case where the moisturizer is applied to the ply base paper, the surface having a smaller concave-convex formed by the creping processing is preferably applied with the moisturizer.

[0085] That is, in the layer in which the surface roughness is different in the size of the arithmetic mean height Sa based on ISO 25178, the face having a small arithmetic mean height Sa is preferably applied with the moisturizer.

[0086] Further, if the moisturizer is applied to a surface having a small arithmetic average height Sa, the surface is smooth and the moisturizer is present in a sufficient amount, so that a smooth feel and softness are imparted.

[0087] Since the outer layer contains the medicinal liquid, it is preferable to perform a calendering process on the laminated sheet after the moisturizer is applied. As a result, the paper is smoothed by external pressure on the outer side of the outer layer, the applied moisturizer is uniformly spread on the surface, the surface becomes smooth, and further "smoothness of the surface" is exhibited.

[0088] Regarding the paper towel to which the moisturizer is applied, the arithmetic average height Sa of the outer surface under non-pressurized conditions (particularly, the exposed surface of the laminated sheet) is preferably 0.005 to 0.012 mm, and particularly preferably 0.006 to 0.008 mm. If the arithmetic average height Sa is within the range, the surface is smooth and exhibits a moderate concavo-convexity, so that, for example, the wiping property against lipstick, foundation, and the like is excellent.

[0089] Here, "non-pressurized conditions" means that the measurement is performed under unbleached (kina-ri) conditions.

[0090] In contrast, if the moisturizer is applied to a surface of the raw sheet layer having a large concavo-convexity formed by the creping process, since the moisturizer is also hygroscopic, a large wrinkle is generated on the surface due to the hygroscopicity over time, the surface shrinks, and the smoothness of the surface is impaired.

[0091] The arithmetic average height Sa is defined by ISO 25178, and represents the average value of the absolute value of the difference in height of each point with respect to the average plane of the surface in a defined area. The smaller the value, the smaller the absolute value of the difference in height of each point with respect to the average plane of the surface, and the flatter the surface is indicated, and the larger the value, the rougher the surface is indicated.

[0092] In addition, in the case of measuring the arithmetic average height Sa, in a paper towel product in which a bundle of paper towels is housed in a package in a pop-up manner, a sample is taken out from the bundle of paper towels, and the measurement surface is set to the surface on which the peak of the fold is located (the arithmetic average curvature of the peak apex (Spc) is also the same).

[0093] Regarding the paper towel of the embodiment, the arithmetic average curvature of the peak apex (Spc) of the outer surface under non-pressurized conditions is preferably 2.8 to 3.5 (1 / mm). The arithmetic average curvature of the peak apex represents the arithmetic average value of the principal curvatures of the peak apex in a defined area. The smaller the value, the more the point of contact with another object has a curvature, and the larger the value, the more the point of contact with another object is sharp.

[0094] In addition, in the sample obtained from the ejected paper bundle, the measurement surface is the surface on which the peak side of the fold is located. When the arithmetic mean curvature of the peak top of the outer surface under non-pressurization (Spc) is 2.8 to 3.5 (1 / Mm), the surface feels smooth, and the wiping property against lipsticks, foundations, and the like is excellent.

[0095] The "arithmetic mean height Sa" and "arithmetic mean curvature of the peak top (Spc)" in this specification refer to values measured using a "one-shot 3D shape measuring instrument VR-3200 (manufactured by KEYENCE Corporation)" (hereinafter, also referred to as a "3D microscope") and a product equivalent thereto (a non-contact three-dimensional measuring instrument).

[0096] The "3D microscope" is capable of measuring a shape by means of structured illumination light irradiated from a light projecting section and from a fringe projection image of an object reflected in a monochrome C-MOS camera, and in particular, is capable of measuring the height, length, angle, volume, and the like of an arbitrary portion using the obtained fringe projection image. In observation, measurement, and image analysis of the image obtained by the "3D microscope", a software "VR-H2A" and a software equivalent thereto can be used. In addition, as to the measurement conditions, conditions in which the field area is 24 mm x 18 mm and the magnification is 12 times are set.

[0097] The specific measurement procedure of the arithmetic mean height Sa and the arithmetic mean curvature (Spc) of the outer surface under non-pressurization is as follows.

[0098] A paper towel (about 50 mm x 50 mm in size in the MD direction x CD direction) as a sample layer was placed on a measurement stage in an unbleached state so that the measuring instrument was in the front surface and the depth direction was the MD direction. In addition, the test piece used in the measurement was a flat portion of the product.

[0099] The screen of the operation software ("VR-H2A") was operated, and three images of a main image (texture), a main image (height), and a 3D image of the sample surface were obtained. Next, the "texture" image displayed by selecting "surface roughness" or the like of the software was converted into a "height" image (an image represented by the gradation of the color tone in the height direction).

[0100] Next, at least the maximum height (Sz), the arithmetic mean height Sa, and the arithmetic mean curvature of the peak top (Spc) were set as measurement parameters to perform the measurement. The size of the measurement range was 3.0 mm x 3.0 mm. If it is the above software, the measurement range can be set by selecting "numerical designation" in "addition of area". The measurement range was set so as not to include the embossed portion, and in addition, the gradation of the color tone in each measurement range on the screen was visually observed to be close to constant.

[0101] The values of the measured maximum height (Sz), the arithmetic mean height (Sa), and the arithmetic mean curvature of the peak apex (Spc) are confirmed, and in the case where the maximum height (Sz) exceeds 0.1000 mm, the value is discarded, and other measurement range is set. In addition, the maximum height (Sz), the arithmetic mean height (Sa), and the arithmetic mean curvature of the peak apex (Spc) are parameters of surface roughness prescribed by ISO 25178. Furthermore, at the time of measurement, in order to remove large undulations of the sheet, measurement is performed under the conditions where the filter has Gaussian correction, there is no S-filter, the F operation is 2-dimensional surface, the L-filter is 0.8 mm, and the terminal processing is on.

[0102] In a range of 3.0 mm square as the measurement range, plane roughness measurement of "maximum height (Sz)", "average arithmetic roughness (Sa)", and "arithmetic mean curvature of the peak apex (Spc)" is performed. The plane roughness measurement of the range of 3.0 mm square in the image is performed at a total of 5 positions, and the average of the 5 positions is taken as the measurement value of "maximum height (Sz)", "average arithmetic roughness (Sa)", and "arithmetic mean curvature of the peak apex (Spc)" of the measurement sample. The range of 3.0 mm square as the measurement range is in the central portion where strain is small in the field area of 24 mm x 18 mm. In addition, the selection of the above-mentioned 5 measurement ranges and "maximum height (Sz)", "average arithmetic roughness (Sa)", and "arithmetic mean curvature of the peak apex (Spc) can be measured simultaneously, but the measurement range Z can also be changed to measure.

[0103] The content of the moisturizer in each layer is 10.0 mass% to 35.0 mass%. Particularly preferably, it is 17.0 to 30.0 mass%. If the content is small, softness is insufficient, and if the content is large, in addition to the tacky feeling on the exposed surface, paper strength is easily reduced.

[0104] is a paper towel in which 3 layers are laminated, and the unit area weight of 1 layer is 15.0 to 22.5 g / m 2 , and the paper thickness of 3 layers is 140 to 270 μm, particularly preferably 176 to 230 μm. In the multi-layer structure of 3 layers, the paper thickness particularly easily affects "softness" and "bulkiness". In the paper towel of the present embodiment, if the paper thickness is in the range, "softness", "bulkiness of bulkiness", and "smoothness of the surface" become remarkable.

[0105] In the case where the paper towel is one in which 4 layers are laminated, the unit area weight of 1 layer is 15.0 to 22.5 g / m 2 , and the paper thickness of 4 layers is 180 to 360 μm, particularly preferably 220 to 320 μm.

[0106] The paper thickness was measured using a dial thickness gauge (thickness measuring instrument) "PEACOCK G type" (Ozaki Mfg. Co., Ltd.) after the test piece was sufficiently conditioned under the conditions of JIS P 8111 (1998), under the same conditions. Specifically, first, it was confirmed that there was no dirt, dust, or the like between the plunger and the measuring table, and the plunger was lowered onto the measuring table, the scale of the dial thickness gauge was moved to align with zero, then the plunger was raised, the test piece was placed on the measuring table, and the plunger was slowly lowered, and the thickness of the thickness gauge at that time was read. At the time of measurement, care was taken to vertically abut the terminal of the metal plunger (a circular flat surface with a diameter of 10 mm) against the paper plane. In addition, the load at the time of paper thickness measurement was about 70 gf. The paper thickness was the average of the measured values obtained by measuring the change site 10 times. With respect to the test piece, a 3-ply product sheet was taken, and the measurement was performed avoiding creases, contact embossed portions, and the like.

[0107] The dry strength in the longitudinal direction of the paper towel of the present embodiment in 3 or 4 plies is preferably 220 to 420 cN / 25 mm. If the dry strength in the longitudinal direction is within this range, "softness", "fluffy fluffiness", and "smoothness of the surface" become remarkable. In addition, it is within a range of sufficient strength for durability.

[0108] In the case where a ply base paper in which the dry strength in the longitudinal direction of 3 plies is excessively high, that is, in which the fibers are arranged closely in the longitudinal direction and are compacted at a high pressure, a sticky feeling is easily generated on the exposed surface due to poor softness and the fact that the moisturizer does not penetrate between the fibers (as is expected).

[0109] In addition, the dry strength in the transverse direction of 3 or 4 plies is preferably 60 to 160 cN / 25 mm. If the dry strength in the transverse direction is within this range, "softness", "fluffy fluffiness", and "smoothness of the surface" become remarkable. In addition, it is within a range of sufficient strength for durability.

[0110] Also, although it is not certain, the "dry tensile strength in the transverse direction" affects the overall "skin touch" functionality, rather than the "softness", "fluffiness" such individual functionality. When the subjects evaluated the paper towel not in terms of the specific evaluation criteria of "softness", "fluffiness", but in terms of the comprehensive evaluation criteria of "skin touch" after freely touching the test sample, it was found that the evaluation of the "skin touch" had a certain correlation with the "dry strength in the transverse direction".

[0111] In addition, the wet paper strength in the transverse direction of 3 or 4 plies of the paper towel of the present embodiment is preferably 50 to 90 cN / 25 mm.

[0112] The ratio of the wet tensile strength in the transverse direction / wet tensile strength in the transverse direction is preferably 0.62 to 0.76. In addition, this value is a measured value in the state of maintaining 3 layers. By setting such a difference in strength, in the usage mode from when it changes from dry to wet, such as when wiping the nose, the user will feel a "firmness (strength, sense of security)". Also, it is difficult to feel a change in the strength of the paper in such a usage mode, and it will have an impact on the sense of "smoothness" in use.

[0113] In addition, the longitudinal direction of the paper is also referred to as the MD direction, and is the flow direction at the time of papermaking. The transverse direction of the paper is also referred to as the CD direction, and is the direction perpendicular to the flow direction (MD direction) at the time of papermaking.

[0114] In addition, the dry (tensile) strength of the paper towel of the embodiment is a value measured based on JIS P 8113, and is a value measured as follows. As for the test piece, a test piece cut to 25 mm (±0.5 mm) in width x about 150 mm in length was used in both the longitudinal direction and the transverse direction. As for the paper towel, the measurement was performed in the state of maintaining multiple layers. As for the testing machine, a Minebea Co., Ltd. force sensor tensile testing machine TG-200N and the like were used. In addition, the clamping interval was set to 100 mm, and the tensile speed was set to 100 mm / min. The measurement was performed in the following steps: the both ends of the test piece were fastened to the clamps of the testing machine, a tensile load was applied to the paper sheet in the up-down direction, and the indicated value (digital value) at the time of paper breakage was read. Five sets of test pieces were prepared in both the longitudinal direction and the transverse direction, respectively, and each was measured 5 times, and the average value of the measured values was taken as the dry tensile strength in each direction. The adjustment of the test piece was performed based on JIS P 8111 (1998).

[0115] Further, the wet (tensile) strength of the paper towel in the embodiment is a value measured in accordance with JIS P 8135 (1998), and is a value measured as follows. As to the test piece, a test piece cut to a width of 25 mm (±0.5 mm) x a length of about 150 mm was used in both the longitudinal direction and the transverse direction. In the case where the paper towel is multilayered, the measurement was performed while maintaining the multilayered state. As to the tester, a Minebea Co., Ltd. tensile tester TG-200N or the like was used. In addition, the clamping interval was set to 100 mm, and the tensile speed was set to 50 mm / min. As to the test piece, a test piece that was cured in a drier at 105°C for 10 minutes was used. The measurement was performed in the following manner: after fastening both ends of the test piece to the clamps of the tester, water was applied to the central portion of the test piece horizontally using a flat pen at a width of about 10 mm, and then, immediately after, a tensile load was applied to the paper sheet in the up-and-down direction, and the indicated value (digital value) at the time of paper breakage was read. Five sets of test pieces were prepared in each of the longitudinal direction and the transverse direction, and each was measured five times, and the average of the measured values was taken as the wet tensile strength in each direction.

[0116] The adjustment of the dry tensile strength and the wet tensile strength can be performed by internally adding a dry paper strength enhancer, a wet paper strength enhancer to the paper stock or the wet paper. As the dry paper strength enhancer, starch, polyacrylamide, CMC (carboxymethyl cellulose) or carboxymethyl cellulose sodium, carboxymethyl cellulose calcium, carboxymethyl cellulose zinc as a salt thereof, etc. can be used. As the wet paper strength enhancer, polyamide polyamine epichlorohydrin resin, urea resin, acid colloid / melamine resin, heat-crosslinking coated PAM, etc. can be used. In addition, in the case where the dry paper strength enhancer is internally added, the amount of addition with respect to the pulp slurry is about 1.0 kg / pulp t or less. Further, the wet paper strength enhancer is preferably a cationic enhancer, and the amount of addition with respect to the pulp slurry is about 5.0 to 20.0 kg / pulp t.

[0117] The fiber material constituting the paper towel is pulp fiber, and is preferably NBKP (softwood kraft pulp) and LBKP (hardwood kraft pulp) used for paper towels. It is also possible to mix and blend waste paper pulp, but since it is difficult for the waste paper pulp to exhibit "softness", it is extremely preferable that the NBKP and the LBKP of virgin pulp alone constitute the paper towel. As the mixing ratio, the mass ratio of NBKP:LBKP = 25:75 to 40:60. If it is within this range, the paper strength and "fluffy fluffiness" required for nose blowing can be felt, and "softness" and "smoothness" can be significantly felt.

[0118] The compression work under 3 layers of 4 groups for a total of 12 layers, or 4 layers of 3 groups for a total of 12 layers is preferably 1.85 to 2.50 gf / cm / cm 2, and particularly preferably 2.18 to 2.35 gf / cm / cm 2 .

[0119] Further, the compression recovery is preferably 46.0 to 54.5%, and particularly preferably 48.0 to 53.0%.

[0120] [Method for manufacturing the paper towel]

[0121] The paper towel and the paper towel product in which the paper towel is bunched and housed in a package body according to the present embodiment can be manufactured by the following manufacturing steps.

[0122] First, a primary blank roll JR (also referred to as a large diameter roll) is manufactured by a papermaking apparatus example X2 shown in Fig. 1 in the following manner. Figure 7

[0123] A paper material, in which a suitable reagent is added to a pulp slurry and is previously adjusted, is supplied to a wire 32w of a wire section 32 from a top box 31 to form a wet paper W (forming step), and then the wet paper W is transferred to a felt 34 of a press section 33, and is subjected to dewatering by being sandwiched by a pair of dewatering rolls 34, 35 (dewatering step).

[0124] Next, after the wet paper after dewatering is attached to a surface of a Yankee dryer 36 to be dried, peeling is performed by a doctor blade 37 to become a dried base paper S1 having a crepe (a once-continuous sheet described later) (creping processing, drying step).

[0125] Then, the dried base paper S1 is wound by a winding unit 38 having a roll 39 in a manner such that a back surface of the dried base paper S1 faces the shaft side of the primary blank roll JR (in a manner to become an inner surface of winding) to form the primary blank roll JR (primary blank roll winding step).

[0126] The primary blank roll JR also differs depending on the performance of the papermaking apparatus X2, but is generally 1000 to 5000 mm in diameter, 1500 to 9200 mm in length (width), and 5000 to 80000 m in roll length.

[0127] In addition, a calendering step (not shown) can be provided at a front stage of the primary blank roll winding step to perform a smoothing treatment of the front and back surfaces of the dried base paper S1 after being peeled by the doctor blade 37.

[0128] Here, the back surface of the dried base paper S1 refers to a surface opposite to a surface that contacts a cylinder of the Yankee dryer 36. In addition, although related to the presence or absence of the calendering step, generally, the surface that contacts the mirror surface of the Yankee dryer is smoother and has superior surface properties.

[0129] ​As explained before, the outer side surface (exposed surface) of the outer side layer of the laminated sheet becomes at least a surface (smooth and excellent in surface properties) which comes into contact with a mirror-finished Yankee dryer, and a moisturizer is applied to the smooth and excellent surface. Thus, the outer side surface (exposed surface) of the outer side layer can be made a surface having a small arithmetic mean height Sa based on ISO 25178.

[0130] As a result, the laminated sheet gives the consumer a smooth and soft feeling of use.

[0131] Here, regarding the once-continuous sheet S1 (laminated base paper) constituting the primary blank roll JR, specifically, the weight per unit area based on JIS P 8124 is 10 to 25 g / m 2 , preferably 12 to 20 g / m 2 , and more preferably 13 to 16 g / m 2 . If the weight per unit area is less than 10 g / m 2 , it is preferable in terms of softness of the paper towel 1, but it cannot ensure appropriate strength. On the other hand, if the weight per unit area exceeds 25 g / m 2 , the paper towel 1 becomes too hard, and the skin touch deteriorates.

[0132] Further, the once-continuous sheet S1 has a creping rate of 10 to 30%, preferably 12 to 25%, and more preferably 13 to 20%. If the creping rate is less than 10%, it becomes a paper towel 1 which is easy to break the paper at the time of processing in the latter stage and has small elongation and no toughness. On the other hand, if the creping rate exceeds 30%, it easily becomes a paper towel 1 which is difficult to control the tension of the sheet at the time of processing, is easy to break the paper, and after the manufacture, also combines with the moisture absorption of the moisturizer, wrinkles occur, and the appearance is poor.

[0133] [Layering process (method and manufacturing apparatus of secondary blank roll)]

[0134] The primary blank rolls of the primary blank roll JR manufactured by the papermaking process are set to three (four in the case of four layers) layering apparatuses also called layering machines, and a single layer of the continuous sheet is fed from each primary blank roll, and a moisturizer is applied, for example, by the coating method described later.

[0135] In the case of 3 layers, the moisturizer is applied to the single layer of the continuous sheet, respectively, or, after the single layer of the continuous sheet is overlapped into 2 layers, the moisturizer is applied from both surfaces of the 2 layers, and for the other layers, the moisturizer is applied in a single layer.

[0136] In the case of 4 layers, the moisturizer is applied to the single layer of the continuous sheet, respectively, or, after the single layer of the continuous sheet is overlapped into 2 layers, the moisturizer is applied from both surfaces of the 2 layers, and similarly, after the other single layer of the continuous sheet is overlapped into 2 layers, the moisturizer can be applied from both surfaces of the 2 layers.

[0137] (calendering)

[0138] After the moisturizer is applied, the laminated continuous sheet can be subjected to calendering.

[0139] The type of calender is not particularly limited, but for the sake of improving the smoothness of the surface and adjusting the thickness of the paper, a soft calender or a hard calender is preferred. The soft calender refers to a calender using a roller coated with an elastic material such as polyurethane rubber, and the hard calender refers to a calender composed of a metal roller.

[0140] The number of calendering sections can be appropriately changed. If a plurality of calendering sections are provided, it has an advantage that the sheet can be sufficiently smoothed even if the processing speed is fast, on the other hand, if one, it has an advantage that it can be provided even if the space is narrow.

[0141] The type of calender, the line pressure of the calender, the number of calendering sections, and the like in the calendering are also controlled as factors in the papermaking, and these factors are preferably appropriately changed depending on the quality of the paper towel, i.e., the thickness of the paper, the surface properties, which are required.

[0142] Then, as needed, in order to achieve the integration of the laminated sheet, and in order to impart designability, embossing can be performed.

[0143] (folding step)

[0144] It is preferred that the folding step be provided continuously with the moisturizer application step or with the subsequent calendering step.

[0145] In this folding step, as shown in Figure 17 , the obtained laminated sheet is folded in a manner that the single side of the preceding laminated sheet S1 and the single side of the subsequent laminated sheet S3 are inserted into the valley fold portion of the laminated sheet S2 in the folding apparatus called a rotary staggered folder (not shown) and the like, sequentially, thereby being laminated into a paper bundle.

[0146] (packaging step)

[0147] The laminated sheet is cut into a shorter paper bundle in a predetermined length, and the shorter laminated sheet is housed in a packaging body (a paper packaging box, a plastic packaging bag, or the like), and in use, the laminated sheet is sequentially taken out from the packaging body in a pop-up manner.

[0148] 〔moisturizer application method〕

[0149] The application method of the moisturizer can be performed by a flexographic printing machine, a gravure printing machine, or the like, a roller transfer device, a spray coating device, or the like.

[0150] In the case of a water-based moisturizer (liquid medicine) in which glycerin, which is a main component for exhibiting hygroscopicity, is applied, and in the case of applying to a sheet material that travels at a high speed, a flexographic printing method or a spray application is particularly preferable.

[0151] In the embodiment, a flexographic printing method can also be employed.

[0152] If the liquid medicine application can be performed by a flexographic printing method, the following advantages and the like are obtained: that is, the flexographic printing plate cylinder (transfer cylinder) is made of resin, and even if the processing speed is high, the application amount can be stabilized while coping with the unevenness of the embossed paper; and by changing the thread count or the mesh volume of the anilox roll or the thread count or the dot area ratio (vertex area ratio) of the flexographic printing plate cylinder, the application amount can be stabilized while easily coping with a wide range of viscosity of the liquid medicine.

[0153] In addition, the liquid medicine application in the liquid medicine application process is particularly preferably a flexographic printing method using a doctor chamber. The doctor chamber method is a method in which a film is produced by directly applying liquid medicine to the surface of an anilox roll (transfer concave roll), has the characteristics that paper dust or air is not easily mixed into the liquid medicine, the physical properties of the liquid medicine are easily stabilized, and the liquid medicine transferred by the anilox roll is uniform, and thus even in the case of low amount application, the application can be appropriately performed.

[0154] (Flexographic printing)

[0155] In the liquid medicine application process, an example in which a flexographic printing machine is used as the liquid medicine application unit 90 is illustrated. In the case of applying liquid medicine to a laminated continuous sheet material, the material of the flexographic printing plate cylinder is particularly preferably silicone rubber.

[0156] The thread count of the flexographic printing plate cylinder is 10 to 60 threads, preferably 15 to 40 threads, and particularly preferably 20 to 35 threads. If the thread count is less than 10 threads, uneven application is often generated, and on the other hand, if the thread count exceeds 60 threads, paper dust is easily clogged.

[0157] The thread count of the anilox roll is 10 to 300 threads, preferably 25 to 200 threads, and particularly preferably 50 to 100 threads. If the thread count is less than 10 threads, uneven application is often generated, and on the other hand, if the thread count exceeds 300 threads, paper dust is easily clogged. The mesh volume of the anilox roll is 10 to 100 cc, preferably 15 to 70 cc, and particularly preferably 30 to 60 cc. If the mesh volume is less than 10 cc, the desired application amount is not obtained, and on the other hand, if the mesh volume exceeds 100 cc, the amount of liquid medicine scattered will increase.

[0158] Here, it is important to be able to stably apply the liquid medicine in the liquid medicine application process, and the line number of the above-mentioned blanket roll and anilox roll related to the operation stability is important. In addition, as a method of transferring the liquid medicine stored in the storage tank to the anilox roll, an appropriate method such as a doctor cavity form, a contact roll form, or the like is adopted. The mode examples of each of the modes in which these flexographic printing are adopted are described in detail.

[0159] <Doctor cavity mode embodiment example>

[0160] In the flexographic printing machine 90 of the doctor cavity form of the flexographic printing, the doctor cavity 92 in which the liquid medicine is stored is disposed in opposition to the rotatable anilox roll 93, and the liquid medicine is transferred from the doctor cavity 92 to the anilox roll 93B. In addition, the rotatable blanket (transfer) roll 94 that comes into contact with the anilox roll 93 and comes into contact with the sheet S1 or S2 is provided, and the liquid medicine is transferred from the anilox roll 93 to the blanket roll 94.

[0161] Further, pressure is applied between the elastic roll 95 that is disposed in opposition to the blanket roll 94 across the sheet S1 or S2 and the blanket roll 94, and the liquid medicine is applied from the blanket roll 95 to the continuous sheet stack.

[0162] As described later, in the case where the elastic roll 95 is used and in the case where the elastic roll 95 is not used, the blanket (transfer) roll 94 can also be disposed in opposition to each other with pressure applied therebetween, and the liquid medicine is applied from the blanket roll 95 to the continuous sheet stack.

[0163] Regarding the control of the application amount of the moisturizer, the degree of the circumferential speed difference of the anilox roll 93 with respect to the blanket roll 94 is implemented, which is appropriate because the control of the application amount of the moisturizer can be performed during the operation.

[0164] <3-layer 1st moisturizer application mode>

[0165] The moisturizer application mode can adopt various modes.

[0166] Figure 8 An example of the 3-layer moisturizer application mode is shown, and regarding the single-layer sheet that is fed out from the three primary bobbins, the 2-layer sheet S2 that is merged into 2 layers in the middle and the single-layer sheet S1 that is kept as it is are supplied to the application device that has three flexographic printing machines 90.

[0167] The liquid medicine is applied to each of the outer sides of the 2-layer sheet S2. The liquid medicine is also applied to the outer sides of the single-layer sheet S1.

[0168] The 2-layer sheet S2 and the single-layer sheet S1 are merged into a 3-layer sheet stack S3 at the merging portion 50. Then, as described above, the calendering process, the embossing process, and the like are performed, and the sheet is guided to the interleaving support.

[0169] Here, according to the present application, the outer side surfaces of the respective layers on the outer side of the laminated sheet S3 are coated with a moisturizing agent (liquid medicine) in a state where the outer side surfaces are surfaces having a small arithmetic average height Sa, and thus, considering the arrangement of the sheets, a laminated sheet of 3 layers can be obtained as Figure 1

[0170] Figure 9 is a view showing a moisturizing agent coating method for 3 layers, and with respect to single-layer sheets fed out from 3 primary material rolls, the single-layer sheets are merged into 3-layer sheets in the middle, are separated into a 2-layer sheet S2 and a single-layer sheet S1 at a separation section 51, and are supplied to a coating device having 3 flexographic printing machines 90.

[0171] The liquid medicine is coated on the outer side surfaces of the 2-layer sheet S2. Then, the 2-layer sheet S2 is merged with the single-layer sheet S1 at the merging section 50 to form a 3-layer sheet, and then the outer side surfaces of the single-layer sheet S1 are also coated with the liquid medicine by the other flexographic printing machines 90, to form a laminated sheet S3 of 3 layers.

[0172] <4-layer 1st moisturizing agent coating method>

[0173] Figure 10 is a view showing a moisturizing agent coating method for 4 layers, and 2 single-layer sheets fed out from 4 primary material rolls are merged into 2-layer sheets in the middle, and the liquid medicine is coated on the outer side surfaces of the 2-layer sheets S2.

[0174] Similarly, the other 2 single-layer sheets are merged into 2-layer sheets in the middle, and the liquid medicine is coated on the outer side surfaces of the 2-layer sheets S2.

[0175] Then, the 2-layer sheets S2 are merged with each other at the merging section 50 to form a laminated sheet S4 of 4 layers.

[0176] <2nd moisturizing agent coating method>

[0177] A sheet coated with a water-based moisturizing agent (liquid medicine) having glycerin as a main component to exhibit hygroscopicity has a tendency to generate an elongation amount and to decrease in strength.

[0178] In particular, in the case where this coating is performed at a high speed, in the above-described 1st moisturizing agent coating method, there is a so-called free running portion in which the sheet is not restrained between the respective coating positions.

[0179] As a result, the sheet coated with the water-based moisturizing agent (liquid medicine) has a case where an elongation amount is generated, and the strength decreases, so that the paper is broken.

[0180] In contrast to this, the 2nd moisturizing agent coating method, that is, a coating method in which each sheet is brought into contact with a roller running at the same speed as the sheet at least during a process from each liquid medicine coating position to a laminated position of 3 layers, is preferable.

[0181] ​<3-layer 2nd moisturizer application method>

[0182] Figure 11 is a diagram showing a 3-layer 2nd moisturizer application method example. As with the 1st moisturizer application method example, each flexographic printing machine 90 is not provided with an elastic roller 95.

[0183] Instead, it is configured to hold the sheet by the blanket (transfer) roller 94 of the 1st flexographic printing machine 90A and the blanket (transfer) roller 94 of the 2nd flexographic printing machine 90B, and to hold the sheet by the blanket (transfer) roller 94 of the 2nd flexographic printing machine 90B and the blanket (transfer) roller 94 of the 3rd flexographic printing machine 90C.

[0184] The 2-layer sheet S2 is applied with the chemical liquid from both faces by the 1st flexographic printing machine 90A and the 2nd flexographic printing machine 90B, and then the outer surface of the single-layer sheet S1 is applied with the chemical liquid by the 3rd flexographic printing machine 90C.

[0185] <4-layer 2nd moisturizer application method>

[0186] Figure 12 is a diagram showing a 4-layer 2nd moisturizer application method example.

[0187] As shown in the diagram, it is configured to hold the sheet by the blanket (transfer) roller 94 of the 1st flexographic printing machine 90A and the blanket (transfer) roller 94 of the 2nd flexographic printing machine 90B, to hold the sheet by the blanket (transfer) roller 94 of the 2nd flexographic printing machine 90B and the blanket (transfer) roller 94 of the 3rd flexographic printing machine 90C, and to hold the sheet by the blanket (transfer) roller 94 of the 3rd flexographic printing machine 90C and the blanket (transfer) roller 94 of the 4th flexographic printing machine 90D.

[0188] The 2-layer sheet S2 is applied with the chemical liquid from both faces by the 1st flexographic printing machine 90A and the 2nd flexographic printing machine 90B, and on the other hand, another 2-layer sheet P2 is applied with the chemical liquid from both faces by the 4th flexographic printing machine 90D and the 3rd flexographic printing machine 90C, and they are merged to form a 4-layer S4.

[0189] Figure 13 is a diagram showing a 4-layer 2nd moisturizer application method example.

[0190] As shown in the diagram, it is configured to hold the sheet by the blanket (transfer) roller 94 of the 1st flexographic printing machine 90A and the blanket (transfer) roller 94 of the 2nd flexographic printing machine 90B, to hold the sheet by the blanket (transfer) roller 94 of the 2nd flexographic printing machine 90B and the blanket (transfer) roller 94 of the 4th flexographic printing machine 90D, and to hold the sheet by the blanket (transfer) roller 94 of the 2nd flexographic printing machine 90B and the blanket (transfer) roller 94 of the 3rd flexographic printing machine 90C.

[0191] In their clamping positions, the two faces of the 2-ply sheet S2, the single-ply sheet S1 as the intermediate sheet, and the single-ply sheet S1 as the outer sheet are each coated with a chemical solution.

[0192] <3rd moisturizer coating method>

[0193] As the 3rd moisturizer coating method, spray coating can also be performed.

[0194] The spray coating can specifically adopt a nozzle-type spray method, a rotary wetting spray method, or the like. As the type of the spray nozzle in the nozzle-type spray method, a hollow cone nozzle that sprays mist in a ring shape, a solid cone nozzle that sprays mist in a circular shape, a solid pyramid that sprays mist in a square shape, a solid rectangular nozzle, a fan nozzle, or the like can be given, and the nozzle diameter, the number of nozzles, the nozzle arrangement method, the number of nozzle arrangements, or the spray distance, the spray pressure, the spray angle, and the concentration and viscosity of the spray liquid can be appropriately selected and used, so that the chemical solution is uniformly sprayed with respect to the width direction of the secondary continuous sheet.

[0195] Further, as the method of atomization in the nozzle-type spray device, either a one-fluid method or a two-fluid method can be selected. Among them, the one-fluid spray method is a method of spraying mist by directly applying pressure to the chemical solution to be sprayed using compressed air to eject mist from the nozzle, or sucking air into the nozzle from a small hole provided in the side surface of the nozzle near the spray outlet to eject mist. Further, the two-fluid spray method can be given as follows: an internal mixing type that mixes and atomizes compressed air and the liquid to be sprayed inside the nozzle; an external mixing type that mixes and atomizes compressed air and the liquid to be sprayed outside the nozzle; and a collision type that makes the mist particles after micro-atomization collide with each other to further uniformize and atomize the mist particles.

[0196] On the other hand, as the rotary wetting spray method, it is a method of sending the liquid to be sprayed to a high-speed rotating disc, atomizing the liquid into fine mist by the centrifugal force of the disc, controlling the diameter of the mist particles by changing the rotation speed of the disc, and controlling the amount of the spray liquid (the amount of application) by changing the amount of the liquid sent to the disc. The rotary wetting coating device has the following advantages: for a small amount of the spray liquid, it can be uniformly coated on the surface of the pigment-coated paper while suppressing the scattering of the mist, and it is easy to adjust the spray speed, the diameter of the mist particles, and the like.

[0197] Figure 14 is an example of a rotary wetting spray device 100. The rotary rotating body 100A is provided in a cover housing chamber (not shown) provided as needed, and the chemical solution is sprayed and applied to the laminated continuous sheet from the spray outlet 100B of the rotary rotating body.

[0198] Figure 15 andFigure 16 The manner of obtaining a 3-ply laminated sheet using the rotary wetting spray device 100 is shown.

[0199] The manner of application is apparent without further detailed explanation.

[0200] The paper bundle of the paper towels folded and laminated by the interleaved holders, such as the rotary interleaved holders, is housed in a package, such as a paper-made packaging box, a film container, in a conventional manner.

[0201] Figure 18 and Figure 19 A paper towel product X1 is shown. A paper bundle 10 of the paper towels folded and laminated in multiple sheets 1 is housed in a housing box having a take-out opening or a take-out opening forming portion formed on an upper surface 20U, and configured so that, when one sheet 1 is taken out from the take-out opening at the time of use, a part of the one sheet of the lower adjacent laminate is exposed from the take-out opening.

[0202] [Housing box]

[0203] The housing box housing the paper bundle 10 of the paper towels 1 is a box body of a regular hexahedron shape also called a carton. The housing box forms the product appearance, and has a carton 20 having a ring-shaped perforated line 25 as a take-out opening forming portion on an upper surface 20U, and a resin-made film 22 covering the range surrounded by the above-mentioned perforated line 25 from the inside of the carton.

[0204] The paper towels 1 housed in the paper bundle in the housing box are taken out one by one from the take-out opening via the above-mentioned gap 24. Then, the part of the paper towel exposed from the take-out opening is supported by the gap 24 to prevent falling into the inside of the carton.

[0205] The paper bundle 10 of the paper towels 1 is folded and laminated in the paper towels 1. More specifically, from the uppermost one of the paper towels 1, the flaps are folded inwardly and laminated in the order of the uppermost one, the second uppermost one, the third uppermost one, and so on. Figure 17 It is also understood that the square paper towels 1 are substantially folded in half so that the edges of the flaps are located on the inner surfaces of the folds of the upper and lower adjacent paper towels, and are overlapped and laminated in an interleaved manner. Here, substantially means to allow several folds of the edges to be formed on the upper surface.

[0206] With regard to the paper bundle 10 of the paper towels 1 of the present laminated structure, when the flap of the uppermost one is pulled upward, the flap of the other one adjacent to the immediately lower side thereof is lifted upward by being pulled upward by friction. Also, the paper bundle 10 of the paper towels 1 of the structure is housed so that the uppermost surface thereof faces the upper surface of the housing box having the take-out opening and the like on the upper surface 20U. When the first one (the one on the uppermost surface) is pulled out from the take-out opening, particularly from the gap 24, a part of the other one located immediately below thereof is exposed. Also, the number of laminated sheets of the paper towels 1 in the present invention is not limited, and if the usual number of laminated sheets of such a product is exemplified, it is 120 to 240 sheets.

[0207] The interleaving folder that performs the folding process can be a device that performs the folding process by a folding plate also called a multi-stand type, a stand type, or a folding plate type, or a device that performs the folding process by a pair of folding rollers also called a rotary type, in addition to the rotary interleaving support described above.

[0208] In the embodiment, it is preferable to use an interleaving folder of the rotary type. In the case of a paper towel product of a multi-layer structure of three or more layers, the number of layers is large and displacement of each layer is likely to occur, but with the interleaving folder of the rotary type, the tension applied to the continuous sheet is weak compared to other devices, and the like, and thus displacement of each layer is less likely to occur, and the folding quality is likely to be good. Therefore, in particular, during processing, the case where the "fluffy feeling" is reduced is less likely to occur.

[0209] Further, it is preferable to perform calendering on the layered sheet. By performing calendering on the layered sheet, it is easy to create a difference in paper thickness between the outer layer and the middle layer. In addition, in particular, in the case where the folding process is performed by the interleaving folder of the rotary type, it is preferable to impart a moisturizer within the interleaving folder. Further, if a first calendering process is performed before the moisturizer is imparted and a second calendering process is performed after the moisturizer is imparted, it is easy to produce a paper towel in which the "fluffy feeling" can be felt and the "softness" and "smoothness" can be significantly felt.

[0210] However, the reason why the "arithmetic average roughness Sa", the "compression work", and the "compression recovery" of the surface measured by one-shot 3D are suitable for "tissue off" is roughly considered as follows.

[0211] The value of the "arithmetic average roughness Sa" is small, and a smooth surface property is imparted.

[0212] The value of the "compression work" is large, and good softness is imparted so that the stage at which compression starts is fast and long.

[0213] The value of the "compression recovery" is small, which means that it is difficult to restore the original state once pressed in, and thus the controllability of the pressure becomes good, and it is helpful to easily control the increase and decrease of the force for wiping off lipstick or foundation.

[0214] Example

[0215] A sample of the paper towel of the embodiment and the paper towel of the existing example was produced, and regarding each item of the functional test column, the following functional test was performed as an evaluation item. The physical property value, the composition value, and the like of each sample were measured as follows. The physical property value, the composition value, and the test results of each sample are shown in Tables 1 and 2 for three layers, and Tables 3 and 4 for four layers.

[0216] [Weight per unit area]

[0217] The measurement was performed in accordance with JIS P 8124 (1998).

[0218] 〔Paper thickness〕

[0219] The measurement was performed in accordance with the above-mentioned thickness measurement method using a dial thickness gauge (thickness measuring instrument) "PEACOCK G type" (manufactured by Ozaki Mfg. Co., Ltd.) under the conditions of JIS P 8111 (1998) as described above.

[0220] 〔Dry tensile strength〕

[0221] The measurement was performed in accordance with the above-mentioned thickness measurement method using a dial thickness gauge (thickness measuring instrument) "PEACOCK G type" (manufactured by Ozaki Mfg. Co., Ltd.) under the conditions of JIS P 8111 (1998) as described above.

[0222] 〔Wet tensile strength〕

[0223] The measurement was performed in accordance with the tensile test of JIS P 8135 (1998).

[0224] As for the test piece, a test piece cut to a width of 25 mm (±0.5 mm) x a length of about 150 mm was used in both the longitudinal direction and the transverse direction. In the case of a paper towel having a plurality of layers, the measurement was performed while maintaining the state of the plurality of layers. As for the testing machine, a tensile testing machine TG-200N manufactured by Minebea Co., Ltd. was used. The clamping interval was set to 100 mm. The measurement was performed in accordance with the following procedure: both ends of a test piece that had been cured for 10 minutes in a dryer at 105°C were fastened to the clamps of the testing machine, then, using a flat pen containing water, water was horizontally applied to the central portion of the test piece at a width of about 10 mm, and then, immediately after that, a tensile load was applied to the paper sheet in the up-and-down direction, and the indicated value (numerical value) at the time of paper breakage was read. The tensile speed was 50 mm / min. Five sets of test samples were prepared in each of the longitudinal direction and the transverse direction, and each was measured 5 times, and the average of the measured values was taken as the wet tensile strength in each direction.

[0225] 〔Softness〕

[0226] The measurement was performed in accordance with the Handle-O-Meter method based on the JIS L 1096 E method. Therein, the test piece was set to a size of 100 mm x 100 mm, and the gap was set to 5 mm. One layer was measured 5 times in each of the longitudinal direction and the transverse direction, and the average of all 10 times was expressed in units of cN / 100 mm. The softness is one of the indices of softness.

[0227] 〔MMD〕

[0228] The coefficient of friction at this time was measured using a frictional sensation tester KES-SE (manufactured by KATO TECH Co., Ltd.) while the contact surface of the friction member was moved at a speed of 0.1 cm / s for 2 cm in substantially the same direction as the direction in which the tension was applied, with the contact surface of the friction member being brought into contact with the surface of the test sample to which a tension of 20 g / cm was applied in the prescribed direction at a contact pressure of 25 g. The value obtained by dividing the coefficient of friction by the friction distance (moving distance = 2 cm) was MMD. The friction member had a contact surface formed by bringing 20 piano wires P each having a diameter of 0.5 mm adjacent to each other, and formed so as to have a length and a width of 10 mm. Unit protrusions each formed of the tips of 20 piano wires P (curvature radius: 0.25 mm) were formed on the contact surface.

[0229] In addition, in the measurement of MMD, the portion including the contact embossed portion, the fold was not measured in advance.

[0230] On the other hand, the test sample was an average value measured by arbitrarily collecting one set each from the upper portion, the central portion, and the lower portion of the paper bundle of the laminated sheet.

[0231] Note 1 in the table (determination of the liquid application surface): two test pieces each obtained by cutting a 2 cm square from each sheet were floated on a spoon with the front side and the back side upward in water, and the side with less water on the test piece after 30 seconds was regarded as the application surface (described as "CT"), and the other side was regarded as the non-application surface (described as "NCT"). In the case where the application surface was not clear, it was described as "-".

[0232] Note 2 in the table is a value obtained by plane roughness measurement in one-shot 3D.

[0233] [Functional test]

[0234] The comparative example 2 was evaluated as "4.0" which was an average value of the scores of the grades of scores 1 to 7 made by 12 evaluators. The higher the score, the higher the evaluation.

[0235] The products of comparative examples 1 to 4 were commercially available products in China. The reference examples were products prepared by the applicant.

[0236] [Table 1]

[0237]

[0238] [Table 2]

[0239]

[0240] [Table 3]

[0241]

[0242] [Table 4]

[0243]

[0244] From the above results, it was found that a 3-ply or 4-ply paper towel which has reduced tackiness of the outer surface while ensuring necessary softness can be obtained.

[0245] In the above experimental examples, the determination of the liquid medicine application surface was simply performed, but in more detail, it was found that it is preferable to perform as follows.

[0246] (1) A flat pan to which 500 mL of water is added, a spoon, and a test sample are prepared.

[0247] (2) In the 3-ply or 4-ply laminated sheet, except for the embossed and creased portions, 2 cm x 2 cm is cut out, and one sheet is divided into individual sheets (3 sheets, 4 sheets).

[0248] (3) The valley side of the divided individual sheets is taken as the A side (test piece A), and the back side thereof is taken as the B side (test piece B). Marking is performed on the A side with a red ballpoint pen.

[0249] (4) The test piece A with the A side facing upward and the test piece B with the B side facing upward are placed on the spoon head of a medicine spoon (about 20 cm in length) for each sheet.

[0250] (5) The test piece A and the test piece B are simultaneously and quietly floated on the water surface in the flat pan.

[0251] (6) After 30 seconds, the state of the water film on the test pieces and the light reflection state are observed by visual observation (photograph).

[0252] (7) The side (test piece) on which the reflection of water on the surface of the test piece is more obvious is taken as the liquid medicine non-application surface "NCT", and the opposite side (test piece) thereof is taken as the liquid medicine application surface "CT".

[0253] (8) The determination is performed by visual observation (photograph), and in the case where there is no significant difference, both sides are recorded as "-".

[0254] In Figure 5 and Figure 6 , test examples are shown.

[0255] The test piece A is related to Figure 5In the case of the sheet B, the surface seen is the B surface = non-liquid-applied surface, and water is wetted from the back surface, and on the upper surface (B surface = non-liquid-applied surface), a larger portion is exposed to water. This is considered to be because, for the moisture passing through the gaps (fine pores) of the paper from the lower side, the surface tension is high due to the small amount of liquid on the upper surface, and the moisture easily spreads on the upper surface.

[0256] In contrast, the case of the sheet B is focused on Figure 6 In the case of the sheet B, the surface seen is the B surface = non-liquid-applied surface, and water is wetted from the back surface, and on the upper surface (B surface = non-liquid-applied surface), a larger portion is exposed to water. This is considered to be because, for the moisture passing through the gaps (fine pores) of the paper from the lower side, the surface tension is high due to the small amount of liquid on the upper surface, and the moisture easily spreads on the upper surface.

[0257] Further, as to the "liquid content", each sheet is adjusted to 10.0 mass% to 35.0 mass% in a standard state of 23°C, 50% R.H according to JIS P8111.

[0258] In measuring the liquid content, each sheet of the liquid-applied multi-ply sanitary tissue paper was peeled, and the weight (a) was measured in a standard state according to JIS P8111. The test sheet was put into a solvent of a ratio of 50:50 of ethanol: acetone using a Soxhlet extractor, and was kept in a state of slight boiling for about 3 hours, and the liquid applied to the liquid-applied multi-ply sanitary tissue paper was dissolved out. The test sheet was taken out, and was dried at 60°C until it became constant, and the weight (b) was measured.

[0259] Explanation of Reference Numerals

[0260] 90: liquid-applied unit; 100: rotary wetting spray device; 1R to 4R: ply; F: applied surface; S1 to S4: sheet (ply); W: non-applied surface.

Claims

1. A method for manufacturing a paper towel, characterized in that: When manufacturing a paper towel composed of a laminated sheet of 3 or 4 layers, Each layer contains a water-based moisturizer that exhibits hygroscopic properties. The method for manufacturing the paper towel comprises: The two surfaces of each layer have a difference in arithmetic mean height Sa based on ISO 25178; applying the moisturizing agent to each of the layers; Here, the moisturizing agent is applied to the outer side surface of each layer located outside the laminated sheet in a state where the outer side surface of each layer has the smallest arithmetic mean height Sa; and Folding the laminated sheet after the application of the moisturizing agent to each layer is completed, The arithmetic mean height Sa of the outer side surface of each layer located outside the laminated sheet under no pressure is 0.005 mm to 0.012 mm. The arithmetic mean curvature Spc of the peak apex under no pressure of the outer side surface of each layer located on the outer side of the laminated sheet is 2.8 mm -1 ~3.5 / mm -1 , The weight per unit area of ​​one layer of the three-layer laminated sheet is 15.0 g / m 2 ~22.5g / m 2 , the thickness of the 3-layer laminated sheet is 140μm to 270μm, The basis weight of one layer of the four-layer laminated sheet is 15.0 g / m 2 ~22.5g / m 2 The paper thickness of the 4-layer laminated sheet is 180 μm to 360 μm.

2. The method for manufacturing a paper towel according to claim 1, wherein: The content of the moisturizing agent in each layer is 10.0% by mass to 35.0% by mass.

3. The method for manufacturing a paper towel according to claim 1, wherein: Coating is performed by flexographic transfer printing.

4. A method for manufacturing a tissue product, wherein a tissue composed of three or four stacked sheets is stored in a storage container, wherein: Each layer contains a water-based moisturizer that exhibits hygroscopic properties. The method for manufacturing the paper towel product comprises: The two surfaces of each layer have a difference in arithmetic mean height Sa based on ISO 25178; applying the moisturizing agent to each layer by flexographic transfer printing; Applying the moisturizing agent to the outer side surface of each layer located outside the laminated sheet in a state where the outer side surface of each layer has the smallest arithmetic mean height Sa; folding the laminated sheet after application of the moisturizing agent to each layer; as well as Then, it is stored in the storage body in a folded state. The arithmetic mean height Sa of the outer side surface of each layer located outside the laminated sheet under no pressure is 0.005 mm to 0.012 mm. The arithmetic mean curvature Spc of the peak apex under no pressure of the outer side surface of each layer located on the outer side of the laminated sheet is 2.8 mm -1 ~3.5mm -1 , The weight per unit area of ​​one layer of the three-layer laminated sheet is 15.0 g / m 2 ~22.5g / m 2 , the thickness of the 3-layer laminated sheet is 140μm to 270μm, The basis weight of one layer of the four-layer laminated sheet is 15.0 g / m 2 ~22.5g / m 2 The paper thickness of the 4-layer laminated sheet is 180 μm to 360 μm.

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