JP2024072248A - Tissue paper and tissue paper product - Google Patents

Abstract

To provide tissue paper which has a thickness and intensity suitable for hand wiping and has multi plies, in which irregularities by embossment are firmly formed, plies are hardly separated, the tissue paper being excellent in touch feeling.SOLUTION: There is provided tissue paper of 3 plies or more plies, basis weight of each layer is greater than 17.8 g/m2 and less than 26.0 g/m2, a paper thickness in a product ply is greater than 350 μm and less than 570 μm. In the tissue paper, humectation tension strength in a vertical direction is greater than 750 cN/25 mm and lower than 1250 cN/25 mm, and humectation tension strength in a lateral direction is greater than 190 cN/25 mm and lower than 400 cN/25 mm. The tissue paper includes 5.0 mass% or greater and less than 18.0% of a moisture keeping solution which includes 70% of glycerin, and has recess parts and salient parts on both surfaces by embossment. These salient parts and recess parts are configured so that, the recess parts on one surface are the salient parts on the other surface. A pattern in plan view of the recess parts and salient parts is a pattern in which the recess parts and the salient parts are arranged on intersection positions of a lattice, in the tissue paper.SELECTED DRAWING: Figure 1

Description

The present invention relates to tissue paper and tissue paper products.

Those who often use tissue paper to wipe objects or dry their hands prefer thick, sturdy tissue with a high basis weight, high strength base paper, and three or more plies.

On the other hand, some tissue papers are given unevenness through embossing. The unevenness caused by embossing creates patterns such as geometric or floral designs on the tissue paper surface, improving its design and its ability to scrape off dirt. It can also improve water absorption. This type of embossing is often in a form called single embossing. With single embossing, there are only recesses on one side and only protrusions corresponding to the recesses on the other side.

In addition, in the case of tissue paper with multiple plies, the plies are often pressed together to prevent them from separating during use. This ply pressing process is also called knurling or edge embossing.

Special Publication No. 2002-530170 Patent No. 5883412

However, tissue paper suitable for wiping objects and hands uses a high basis weight and high strength base paper, and is made up of three or more plies, so the unevenness created by the embossing process is not properly formed, and the compression process such as edge embossing tends to be insufficient, resulting in problems such as the plies easily separating during use.

On the other hand, there are differences in how tissue paper is used depending on the person, country, and region. This is thought to be due to differences in lifestyle and cultural patterns. For example, there are regions where soft tissue paper is used for wiping the face and firm tissue paper for wiping hands and objects, and regions where tissue paper is used for multiple purposes such as wiping the face, hands, and objects without being differentiated.

And even in the latter areas, there is a demand for tissue paper that is suitable for specific uses, such as wiping hands. In particular, in areas where multiple uses are assumed, there is a demand for tissue paper that is easy to use for specific uses, such as wiping hands, on the premise that it can be used without complaint for each of these purposes, such as wiping the face, hands, and objects. For example, particularly in China, there is a demand for tissue paper that is suitable for specific uses, while assuming multiple uses.

The main objective of the present invention is to provide a tissue paper that is suitable for multiple uses, having a thickness and strength suitable for hand wiping, excellent design due to the well-formed unevenness created by the embossing process, and is resistant to ply separation, and further has sufficient touch and wiping properties even when used for wiping the face, etc.

The first means according to the present invention for solving the above problem is:
A tissue paper having three or more plies,
The basis weight of each layer is greater than 17.8 g/ ^m2 and less than 26.0 g/ ^m2 ;
The thickness of the product ply is more than 350 μm and less than 570 μm,
The wet tensile strength in the longitudinal direction is more than 750 cN/25 mm and less than 1250 cN/25 mm, and the wet tensile strength in the transverse direction is more than 190 cN/25 mm and less than 400 cN/25 mm;
A moisturizing liquid containing 70% or more of glycerin is contained in an amount of 5.0% by mass or more and less than 18.0% by mass,
The two surfaces have concave and convex portions formed by embossing, and the concave portions on one surface correspond to the convex portions on the other surface.
The pattern of the concave and convex portions in plan view is a pattern in which the concave and convex portions are arranged at intersection positions of a lattice.
The tissue paper is characterized by the above.

The second method is
The tissue paper according to the first aspect of the present invention has a water absorption of 612 g/ ^m2 or more and a softness of more than 250 mN and less than 440 mN.

The third method is
The tissue paper according to the first aspect has 15 to 17 recesses and protrusions per ^cm2 on one side.

The fourth measure is
a steel match embossing process is performed by using a pair of embossing rolls, in which a recess formed on a surface of one embossing roll fits with a protrusion formed on a surface of the other embossing roll, and a protrusion formed on the surface of the one embossing roll fits with a recess formed on a surface of the other embossing roll,
In the tissue paper according to the first aspect, the areas of the recesses and protrusions in the embossing rolls are set to be more than 1.65 ^mm2 and less than 2.80 ^mm2 .

The fifth measure is:
The tissue paper according to the fourth aspect of the present invention has a height of the protrusions of the embossing roll that is more than 0.13 mm and less than 0.35 mm.

The sixth method is:
The tissue paper according to the fourth or fifth aspect, wherein the area ratio of the recesses of the embossing roll is 25% or more.

The seventh measure is:
The tissue paper product is characterized in that the tissue paper according to the first to sixth aspects is folded and stacked to form a pop-up bundle, and the bundle is stored in a storage box or a packaging film.

The present invention provides tissue paper that has a thickness and strength suitable for hand wiping, has excellent design due to the well-formed unevenness created by the embossing process, is resistant to ply separation, and is suitable for multiple uses such as wiping the face with a pleasant feel and sufficient wiping properties.

FIG. 2 is a schematic plan view of the tissue paper according to the embodiment. FIG. 2 is an enlarged plan view of the tissue paper according to the embodiment. FIG. 1 is a schematic cross-sectional view of a three-ply embodiment. FIG. 1 is a schematic cross-sectional view of a four-ply embodiment. FIG. 2 is a schematic diagram for explaining embossing. FIG. 2 is a surface diagram of an embossing roll for explaining embossing. FIG. 2 is a cross-sectional view of an embossing roll for explaining embossing. FIG. 1 is a schematic perspective view of a tissue paper product. 11 is a cross-sectional view of a storage example for a storage box. FIG. FIG. 13 is an explanatory diagram of a pop-up type folding form. FIG. 2 is a schematic cross-sectional view of a preferred three-ply embodiment. FIG. 1 is a schematic cross-sectional view of a preferred four-ply embodiment. FIG. 13 is a schematic cross-sectional view of another three-ply embodiment. FIG. 13 is a schematic cross-sectional view of another four-ply embodiment. FIG. 13 is a schematic diagram of an example of obtaining a primary continuous sheet. FIG. 1 is a schematic diagram of a three-ply coating example. FIG. 13 is a schematic diagram of another example of three-ply coating. FIG. 1 is a schematic diagram of a four-ply coating example. FIG. 13 is a schematic diagram of another example of a three-ply coating. FIG. 13 is a schematic diagram of another example of a four-ply coating. FIG. 13 is a schematic diagram of yet another example of a four-ply coating. FIG. 1 is a schematic diagram of an example of a spray coating facility. FIG. 1 is a schematic diagram of an example of three-ply coating using an example spray coating equipment. FIG. 13 is a schematic diagram of another example of application of three ply by example spray application equipment.

The present invention will be further described below with reference to embodiments thereof.
An embodiment of the tissue paper 2 in which 3 or 4 plies are laminated will be described. FIG. 1 shows a plan view of one sheet of the tissue paper 2, FIG. 2 shows a partially enlarged view of the plan view, FIG. 3 shows a cross-sectional view of 3 plies, and FIG. 4 shows a cross-sectional view of 4 plies. First, since it is 3 or 4 plies rather than 2 plies, it gives a sufficient "thickness" and "firmness" suitable for "hand wiping" and "object wiping" applications. Furthermore, it becomes easier to achieve the required strength. Note that 3 plies refers to a form in which three plies (sheets) S1 to S3 are laminated, and 4 plies refers to a form in which four plies (sheets) S1 to S4 are laminated. Each ply (sheet) is crepe paper.

The basis weight of one ply of the tissue paper of this embodiment is more than 17.8 g/ ^m2 and less than 26.0 g/ ^m2 , preferably 19.8 g/ ^m2 or more and 24.0 g/ ^m2 or less, particularly preferably 20.1 g/m2 or more and 23.6 g/ ^m2 or less. The basis weight in this range is relatively high. Therefore, with "3 plies or 4 plies" under this basis weight, sufficient strength can be secured for "hand wiping" and "object wiping", and further, "thickness" and "firmness" are significantly felt. Furthermore, since the paper tends to become hard when the basis weight is high and soft when the basis weight is low, it is considered that the basis weight also has a large effect on "softness". By setting the basis weight of each layer within this range and providing unevenness by moisturizing liquid and embossing processing described later, "softness" and "smoothness" are easily felt, and it can be used for "face wiping" without dissatisfaction, and can be used for multi-use. The basis weight is a value measured based on JIS P 8124 (1998).

The overall paper thickness (product ply) of the tissue paper of this embodiment is more than 350 μm and less than 570 μm. It is preferably 360 μm or more and 499 μm or less, and particularly preferably 387 μm or more and 472 μm or less. In a multi-ply structure of three or more plies, the paper thickness is particularly likely to affect "softness" and "thickness". In the tissue paper of this embodiment, when the paper thickness is within this range, the "softness" and "thickness" are remarkable, and a sufficient "thickness" suitable for "hand wiping" and "object wiping" applications is felt. In addition, when combined with other configurations, it can express a satisfactory "softness" when used for "face wiping". Furthermore, combined with the unevenness caused by the embossing process, the "smoothness" is also remarkable.

The paper thickness is measured using a dial thickness gauge (thickness measuring device) "PEACOCK G type" (manufactured by Ozaki Manufacturing Co., Ltd.) under the same conditions after thoroughly conditioning the test piece under the conditions of JIS P 8111 (1998). Specifically, after making sure that there is no dirt or dust between the plunger and the measurement table, the plunger is lowered onto the measurement table, the dial thickness gauge's scale is moved to set the zero point, the plunger is then raised, the test piece is placed on the measurement table, and the plunger is slowly lowered to read the gauge at that time. When measuring, care should be taken to ensure that the metal plunger terminal (a circular flat surface with a diameter of 10 mm) is perpendicular to the paper plane. The load when measuring the paper thickness is approximately 70 gf. The paper thickness is the average value of the measured values obtained by performing this measurement 10 times at different locations. The test piece is a 3-ply product sheet taken and measured while avoiding folds and contact embossed parts.

In addition, the wet tensile strength of the tissue paper of this embodiment with three or four plies in the longitudinal direction is more than 750 cN/25 mm and less than 1250 cN/25 mm, and the wet tensile strength of the tissue paper with the transverse direction is more than 190 cN/25 mm and less than 400 cN/25 mm. More preferably, it is 767 cN/25 mm or more and 1235 cN/25 mm or less, and particularly preferably, it is 822 cN/25 mm or more and 1169 cN/25 mm or less. It is desirable that the wet tensile strength of the tissue paper with three or four plies in the transverse direction is more than 150 cN/25 mm and less than 450 cN/25 mm. More preferably, it is 205 cN/25 mm or more and 381 cN/25 mm or less, and particularly preferably, it is 224 cN/25 mm or more and 329 cN/25 mm or less. Note that this value is measured when each ply is stacked, that is, when the three or four plies are still stacked. The wet tensile strength is related to the strength when absorbing moisture, such as when wiping with wet hands, popping up the tissue paper with wet hands to take it out, wiping off moisture from objects, blowing nose, and absorbing lotion when removing makeup. If it is in this range, in combination with other configurations, it is sufficient strength, especially when wiping with wet hands and popping up the tissue paper with wet hands to take it out. In addition, in a pop-up type tissue paper product folded by a rotary interholder, which is a preferred manufacturing method described later, the lengthwise direction of the tissue paper is the pull-out direction. With the above-mentioned lengthwise wet tensile strength, the tissue paper can be pulled out smoothly without breaking even when pulled out with wet hands. The lengthwise direction of the paper is also called the MD direction, and is the flow direction during papermaking. The cross direction of the paper is also called the CD direction, and is the direction perpendicular to the flow direction (MD direction) during papermaking.

The wet tensile strength of the tissue paper in the embodiment is a value measured in accordance with JIS P 8135 (1998) and is a value measured as follows. The test piece is cut to a width of 25 mm (±0.5 mm) x length of about 150 mm in both the vertical and horizontal directions. If the tissue paper is multi-ply, it is measured as multi-ply. The test machine used is a load cell tensile tester TG-200N manufactured by Minebea Co., Ltd. or an equivalent machine. The gripping distance is set to 100 mm, and the tensile speed is set to 50 mm/min. The test piece used is one that has been cured for 10 minutes in a dryer at 105°C. After clamping both ends of the test piece to the grips of the test machine, water is applied horizontally to the center of the test piece with a width of about 10 mm using a flat brush soaked in water, and then a tensile load is immediately applied to the paper piece in the vertical direction, and the measurement is performed by reading the indicated value (digital value) when the paper breaks. Five sets of samples are prepared in each of the longitudinal and transverse directions, and measurements are taken five times in each direction, with the average of the measurements being the wet tensile strength in each direction.

Furthermore, the dry tensile strength of the tissue paper of this embodiment with 3 or 4 plies in the longitudinal direction is preferably 1958 cN/25 mm or more and 2531 cN/25 mm or less, and particularly preferably 1859 cN/25 mm or more and 2353 cN/25 mm or less. If the dry strength in the longitudinal direction is within this range, the "thickness" and "firmness" will be noticeable, and it can be said to be a high strength range that is particularly suitable for use in "hand wiping" and "wiping objects." If a ply base paper is used that does not have the longitudinal dry strength of the present invention, in which the fibers are densely arranged in the longitudinal direction and compressed under high pressure, it will be difficult for the fibers to be sufficiently loosened when the moisturizing liquid according to the present invention or the unevenness formed by embossing processing described below is used, and softness will be difficult to achieve.

In addition, the dry tensile strength of three or four plies in the horizontal direction is preferably 477 cN/25 mm or more and 691 cN/25 mm or less, and particularly preferably 509 cN/25 mm or more and 620 cN/25 mm or less. If the dry strength in the horizontal direction is within this range, it has a strength suitable for "hand wiping" and "wiping objects" with a "thickness" and "firmness", and when combined with the moisturizing solution according to the present invention described below and the unevenness caused by the embossing process, it can also be "softness" and "smoothness" that is satisfactory for "wiping the face". Furthermore, although it is not certain, the "dry tensile strength in the horizontal direction" affects the overall "skin feel" sensation, rather than individual sensations such as "softness" and "thickness". When subjects were allowed to freely touch the samples and then asked to rate the quality of the tissue paper using the overall evaluation criterion of "texture" rather than specific evaluation criteria such as "softness" or "thickness," it was found that there was a certain correlation between the evaluation of "texture" and "horizontal dry strength."

The dry (tensile) strength of the tissue paper of the embodiment is a value measured based on JIS P 8113, and is a value measured as follows. The test pieces are cut to about 25 mm (±0.5 mm) wide x 150 mm long in both the vertical and horizontal directions. The tissue paper is measured as a multi-ply. The test machine is a load cell tensile tester TG-200N manufactured by Minebea Co., Ltd. or an equivalent machine. The gripping distance is set to 100 mm, and the pulling speed is set to 100 mm/min. The measurement is performed by clamping both ends of the test piece to the grips of the test machine, applying a tensile load to the paper piece in the vertical direction, and reading the indicated value (digital value) when the paper breaks. Five sets of samples are prepared in both the vertical and horizontal directions, and measurements are taken five times for each direction, and the average of the measured values is the dry tensile strength in each direction. The sample is adjusted in accordance with JIS P 8111 (1998).

The dry tensile strength and wet tensile strength can be adjusted by adding a dry strength enhancer or a wet strength enhancer to the paper stock or wet paper. Dry strength enhancers include starch, polyacrylamide, CMC (carboxymethylcellulose) or its salts such as sodium carboxymethylcellulose, calcium carboxymethylcellulose, and zinc carboxymethylcellulose. Wet strength enhancers include polyamide polyamine epichlorohydrin resin, urea resin, acid colloid melamine resin, and thermal crosslinking coating PAM. When a dry strength enhancer is added, the amount added to the pulp slurry is about 1.0 kg/t pulp or less. The wet strength enhancer is preferably cationic, and the amount added to the pulp slurry is about 5.0 to 20.0 kg/t pulp.

The tissue paper of this embodiment is a moisturizing tissue paper. In other words, it contains a moisturizing liquid that enhances moisture absorption. The moisturizing liquid contains 70% or more by mass of glycerin, preferably 75% or more by mass and less than 80% by mass. Glycerin exhibits moisture absorption as well as moisture retention. It is desirable for the water content to be 15 to 20% by mass. Furthermore, liquid paraffin can be contained to improve surface properties, particularly smoothness. Furthermore, 1,3-propanediol can be contained in an amount of 6.1% by mass or more and 12.6% by mass or less, if necessary. 1,3-propanediol reduces the "sticky feeling" caused by glycerin.

The tissue paper may contain moisturizing agents such as glycerin as well as known auxiliary agents. Examples of auxiliary agents include antibacterial agents, moisturizing auxiliary components such as sorbitol, hydrophilic polymer gelling agents for increasing the moisture retention in the tissue paper, surfactants and softening agents, oily components such as the liquid paraffin mentioned above for aiding in the development of smoothness, and other components such as emulsifiers, preservatives, and defoamers for stabilizing moisturizing agents and improving application properties. The blending amounts of components such as moisturizing auxiliary components and hydrophilic polymer gelling agents for increasing moisture retention should be such that they do not excessively affect "thickness," "softness," and "smoothness." Specifically, the blending amount should be 1.0% by mass or less, preferably 0.6% by mass or less, and more preferably 0.5% by mass or less.

The content of the moisturizing liquid is 3.5% by mass or more and less than 16.5%. More preferably, it is 3.9% by mass or more and 15.7% by mass or less. This content of the moisturizing liquid is the content in the entire 3-ply or 4-ply. Note that the concentration of the moisturizing liquid may vary between the two surface plies and the middle ply depending on the application form of the moisturizing liquid. For example, when the moisturizing liquid is applied to each ply and then laminated, when the moisturizing liquid is applied from one side after lamination, when the moisturizing liquid is applied from both sides after lamination, etc., the concentration of the moisturizing liquid in each ply may vary depending on the application form. To achieve this content of the moisturizing liquid, it is sufficient to apply 5.0 to 20.0% by mass of the liquid relative to the mass of the base paper, although this is not necessarily limited.

The moisturizing agent content ("chemical agent content") is the percentage of moisturizing agent contained in each sheet conditioned under the standard conditions of JIS P8111, 23°C and 50% R.H. To measure the chemical agent content, each sheet (each ply) of tissue paper coated with the chemical agent is peeled off, and the weight (a) is measured under the standard conditions of JIS P8111. The test piece is placed in a solvent of ethyl alcohol:acetone in a ratio of 50:50 in a Soxhlet extractor and kept in a light boiling state for about 3 hours to dissolve the chemical agent applied to the chemical agent-coated multi-layer sanitary tissue paper. The test piece is removed and dried at 60°C until it reaches a constant weight (b), and then the chemical agent content is calculated by subtracting the weight (b) from the weight (a), and the chemical agent content is calculated from the weight (a) and the chemical agent content.

Here, in moisturizing tissue (also called lotion tissue), a certain amount of moisturizer needs to be applied so that the user feels softness when using the tissue. The tissue paper of the embodiment is not limited in the form of application, but it is preferable that the moisturizing liquid is contained almost evenly in each ply. In other words, when the dry moisturizer (liquid) content of the product is 100, it is preferable that the dry moisturizer (liquid) content of each ply is in the range of 92.0 to 108.0. More preferably, the dry moisturizer (liquid) content of the ply is in the range of 95.0 to 104.0.

In order to ensure that the moisturizing liquid is contained almost evenly in each ply, a manufacturing method in which a moisturizing liquid that exhibits hygroscopicity is applied to each ply and then laminated is particularly desirable. To explain this in detail, FIG. 11 shows one form in which a moisturizing liquid is applied to each ply of three layers (1R, 2R, 3R). FIG. 12 shows one form in which a moisturizing liquid is applied to each ply of four layers (1R, 2R, 3R, 4R). FIG. 13 shows one form in which a moisturizing liquid is applied to both surfaces after three layers (1R, 2R, 3R) are laminated. FIG. 14 shows one form in which a moisturizing liquid is applied to both surfaces after four layers (1R, 2R, 3R, 4R) are laminated. In addition, the coated surface F and the non-coated surface W of the moisturizing liquid are shown. There is a considerable gradient in the concentration of the moisturizing agent in the thickness direction from the coated surface F to the non-coated surface W, so the concentration gradient is illustrated by a gradation.

In the configurations shown in Figures 13 and 14, the moisturizing solution is not applied directly to the intermediate plies (2R in Figure 13, 2R and 3R in Figure 14), so the amount of moisturizing solution applied to the surface plies tends to be large, which can cause the outer surface of the surface plies to become sticky. When the moisturizing solution is applied after lamination, the moisturizing solution behaves such that it penetrates and diffuses throughout the entire surface over time from the applied surface. However, if the amount of moisturizing solution applied is small, the amount of moisturizing solution transferred to adjacent plies may be small. On the other hand, if the amount of moisturizing solution applied is large, the moisturizing solution transfers to adjacent plies, but a difference in level may occur between the content of the moisturizing solution in the surface ply to which the moisturizer is applied and the content of the moisturizing solution in the adjacent plies. This concentration gradient may be gentler due to seasoning, but may not be the case. In the configurations shown in Figures 11 and 12, the moisturizing solution is applied directly to each ply, so the moisturizing solution is also applied to the intermediate plies. Therefore, if the moisturizing liquid is applied to each ply, the intermediate ply (2R in FIG. 11, 2R and 3R in FIG. 12) can also be made to contain a water-based moisturizing liquid, which makes the intermediate ply soft and the entire laminated sheet soft. As a result, the amount of moisturizing liquid contained in the outer layer ply can be reduced, which makes it easier to eliminate or suppress the "sticky feeling" caused by the moisturizing liquid on the outer surface of the surface ply (the exposed surface of the laminated sheet), and makes it easier to feel that moisture has been wiped off well, especially when "wiping with hands" or "wiping off objects."

Here, moisturized tissue paper containing a moisturizing liquid generally tends to have a low water absorption amount because the moisture content is increased due to the hygroscopicity of the moisturizing liquid. The tissue paper of this embodiment can exhibit sufficient water absorption suitable for "hand wiping" and "object wiping" applications by increasing the basis weight and paper thickness. Here, the water absorption amount of the tissue paper of this embodiment is not necessarily limited, but if the water absorption amount is 612 g/ ^m2 or more, it can be used without dissatisfaction for "hand wiping" and "object wiping" applications, and it can be said that it has a sufficient water absorption amount even for "face wiping" applications such as wiping the skin such as makeup remover. In the tissue paper of this embodiment, this water absorption amount can be achieved by combining the unevenness caused by the embossing process, the number of plies, the paper thickness and the basis weight. The water absorption amount is measured as follows. The test environment is 23°C and humidity is 50%. The test piece is cut to 100 mm x 100 mm (±0.5 mm). The test liquid is tap water at room temperature. Prepare a tray to hold the test specimen and the test liquid. The wire mesh on which the test specimen is placed has an outer frame of 120 mm x 120 mm, the wire thickness of the outer frame is 3.0 mm, the inner frame has a 10 mm grid, the wire thickness of the inner frame is 0.5 mm, and a handle is attached. The cut test specimen is placed on a measurement container such as a petri dish, and the weight of the container is measured and recorded to two decimal places. The test specimen is placed on the wire mesh to absorb the test liquid. At this time, the test specimen is not immersed in the water, but is held so that the lower limit of the test specimen touches the test liquid. After the test liquid has soaked into the surface of the test specimen, the wire mesh is lifted vertically from the container containing the test liquid, the test specimen is folded in four with tweezers, and left to stand for 25 to 26 seconds. Note that this should be within 30 seconds after being lifted vertically from the container. After that, the test specimen is grasped with tweezers, and transferred back to the container by sliding it parallel to the wire mesh, and the weight of the container is measured and recorded to two decimal places. The amount of water absorption is calculated from the difference between the weight before and after immersion and recorded to the first decimal place. The same sample is measured three times and the average value is taken as the measured value.

The fiber material that makes up the tissue paper is pulp fiber, and is preferably NBKP (coniferous kraft pulp) and LBKP (hardwood kraft pulp) used in tissue paper. Recycled paper pulp may be blended, but since recycled paper pulp is difficult to express "softness," it is extremely desirable for the paper to be composed only of virgin NBKP and LBKP. The blending ratio, by mass, is NBKP:LBKP = 35:65 to 48:52. This range particularly affects the formation of unevenness by embossing, and while the paper strength and "thickness" required for "hand wiping" and "object wiping" applications can be felt, the "softness" and "smoothness" can also be felt remarkably for "face wiping" applications.

As shown in Figs. 1 to 4, the tissue paper 2 of this embodiment characteristically has recesses 20 and protrusions 21 embossed on both surfaces, with the recesses 20 on one surface corresponding to the protrusions 21 on the other surface. Furthermore, the pattern of the recesses 20 and protrusions 21 in plan view is a pattern in which the recesses 20 and protrusions 21 are arranged at the intersections of a lattice. Note that this pattern can also be said to be a pattern in which the recesses 20 and protrusions 21 are arranged at the intersections of virtual lines L drawn in a lattice on the tissue paper surface, as shown in Fig. 1. Note that the intersection angle of the lattice, i.e., the intersection angle between the virtual lines, is not necessarily limited. It is preferably 60 to 120°, and particularly preferably 90±5°. Furthermore, the angle ∠α of the virtual line L with respect to the vertical direction of the paper is preferably 30 to 60°, and particularly preferably 45±1°.

The tissue paper 2 of this embodiment has the above-mentioned paper quality physical properties such as basis weight and paper thickness, and has concave portions 20 and convex portions 21 on both surfaces, so that the difference in surface properties between the two surfaces is easily felt, and similar water absorption and softness are obtained on both surfaces, and the depth of the concave portions and convex portions gives both surfaces approximately the same wiping properties. In this way, both surfaces can be used with the same quality, so there is no difference in the feeling when touching the skin, and it is particularly suitable for applications such as "wiping hands" and "wiping the face". To explain more specifically, first, the tissue paper of this embodiment is easy to feel cushioning because the parts that first come into contact with the skin on both surfaces when used are the tops of the convex portions. In addition, the contact area with the skin is small, and combined with the inclusion of a moisturizing liquid, it has excellent slipperiness and is easy to feel "smoothness". Furthermore, when pressed against the skin, the cushioning properties of the convex portions make it easy to feel a "sense of thickness" and "softness". Furthermore, this pattern of concave and convex portions has concave portions 20 and convex portions 21 alternately positioned at regular intervals in the vertical and horizontal directions on both surfaces, so the roughness caused by the convex portions 21 is less noticeable, and as a result, it is easier to feel "smooth." Furthermore, because the paper surfaces on both surfaces are uneven, it is easy to feel a "thickness" that leads to a sense of security when wiping items other than skin, and it is also excellent in terms of wiping and scraping off dust and dirt.

In the case of the number of plies, basis weight and paper thickness of the tissue paper of this embodiment, it is usually difficult to form a characteristic embossed shape in which the concave portions 20 and convex portions 21 are embossed on both surfaces, and the concave portions 20 and convex portions 21 correspond to the convex portions 21 on the other surface. By setting the content of the moisturizing liquid containing 70% or more of glycerin to 5.0% by mass or more and less than 18.0% by mass, as in the embodiment, it is possible to form the concave portions 20 and convex portions 21 with a firm design. In other words, by embossing the laminated sheet containing the moisturizing liquid and having increased flexibility, it is possible to form the concave portions 20 and convex portions 21 with excellent design of the embodiment. In this case, if the moisturizing liquid is applied to each ply as described above, the intermediate ply is also flexibly deformed during embossing, making it easy to form the concave portions 20 and convex portions 21, and moreover, the concave portions 20 and convex portions 21 are unlikely to return to flat over time, making it possible to form the concave portions 20 and convex portions 21 with a firm design.

The tissue paper 2 of this embodiment has recesses 20 and protrusions 21 on both surfaces, and their characteristic arrangement, combined with the paper thickness, number of plies, and basis weight configuration, as well as the inclusion of moisturizing liquid, makes it suitable for "wiping hands" and "wiping objects" in terms of "thickness," "firmness," and strength, while also being suitable for use in contact with the skin in terms of "softness," "absorbency," and "smoothness," making it fully suitable for multiple uses.

Here, the softness of the tissue paper of this embodiment is not necessarily limited, but it is desirable that the softness is more than 250 mN and less than 440 mN. More preferably, it is 268 mN or more and 410 mN or less, and particularly preferably, it is 285 mN or more and 363 mN or less. When the softness is in the range of more than 240 mN and less than 440 mN, it can be said that the softness is sufficient, particularly in terms of multi-use properties and excellent skin wiping properties. This softness can be achieved by the above-mentioned embossed recesses and protrusions, their characteristic arrangement, and the configuration of the paper thickness, number of plies, and basis weight. Note that this softness is a value measured by the handle-o-meter method in accordance with JAPAN TAPPI No. 34, and the sample length is 100 mm. The clearance is 5 mm. The measurement is performed by peeling off the two-ply sheet one by one, and then stacking the sheets. The value of the softness is the average value of 20 measurements, five times each on the front and back sides in the vertical and horizontal directions.

On the other hand, the embossing means for forming the recesses 20 and protrusions 21 in the tissue paper 2 of this embodiment is not necessarily limited, but it is preferable to form them by steel match embossing as shown in Figures 5 to 7. In steel match embossing, as shown in Figure 6, the recesses 30 formed on the surface of one embossing roll 40A and the protrusions 31 formed on the surface of the other embossing roll 40B fit together, and the protrusions 31 formed on the surface of the one embossing roll 40A and the recesses 30 formed on the surface of the other embossing roll 40B fit together, forming unevenness on the paper surface by passing the processed base paper S between a pair of hard embossing rolls 40A and 40B made of metal or the like. Figure 7 shows an embodiment of a three-ply process in which sheets S1, S2, and S3 are paid out from three raw rolls A1, A2, and A3, each sheet is coated with a chemical solution by a chemical solution coating means 90, and then stacked to form the processed base paper S, which is passed between the embossing rolls 40A and 40B. In this steel match embossing process, as shown in FIG. 7, the convex portion 31 of one embossing roll is positioned to fit into the concave portion 30 of the other embossing roll, and the concave portions 20 and convex portions 21 are formed by embossing on both surfaces in this embodiment, with the concave portion 20 on one surface corresponding to the convex portion 21 on the other surface. Note that the material of the embossing roll peripheral surface in steel match embossing is not necessarily limited to steel. It may be formed of a hard material such as another metal.

In this steel match embossing process, the fibers are easily compressed at the bottom 20B of the recess 20 (the top 21t of the protrusion 21 on the opposite side) as shown in Figures 3 and 4 during processing, while the slope 22 is easily stretched and the fibers are easily broken down. This improves the smoothness of the top 21t of the protrusion 21 that touches the skin, and makes it easier to obtain cushioning properties for the entire protrusion, improving the suitability for skin-contact applications such as the previously mentioned "softness," "absorbency," and "smoothness." Furthermore, the paper quality physical properties such as basis weight and paper thickness do not reduce the "firmness" and "thickness" that are suitable for "hand wiping" and "object wiping" applications. Therefore, the effects of the tissue paper of this embodiment, which can be fully adapted to multiple uses, become more pronounced. In particular, the smoothness and cushioning effect achieved by the fiber density at the bottom 20B (top 21t) and slope 22 of the recess 20 (protrusion 21) in this steel match embossing process is also related to the fiber ratio of NBKP:LBKP described above, especially the high ratio of LBKP in a slightly higher proportion. In other words, the effect is more pronounced with the above NBKP:LBKP and steel match embossing. Also, as described above, the inclusion of a moisturizing liquid promotes fiber movement, firmly forming the recess 20 and protrusion 21.

The number of recesses 20 or protrusions 21 formed by embossing in the tissue paper of this embodiment is not necessarily limited, but is preferably 7 to 17 per ^cm2 on one side, and more preferably 15 to 17. This number makes it easier to achieve effects that are particularly suitable for skin-contact applications, such as "softness,""absorbency," and "smoothness," while also being fully compatible with other general uses, i.e., multiple uses.

The shape of the recesses 20 (protrusions 21) created by the embossing of the tissue paper of this embodiment is not necessarily limited, but is preferably a circle, an ellipse, or a rectangle with rounded corners. Since there are no corners, it is easy to feel a "smoothness" when it touches the skin.

Here, the areas of the recesses 30 and protrusions 31 formed on each of the embossing rolls 40A, 40B for forming the recesses 20 and protrusions 21 on the tissue paper of this embodiment are not necessarily limited, but are preferably greater than 1.65 ^mm2 and less than 2.80 ^mm2 . Tissue paper having the recesses 20 and protrusions 21 formed by such embossing rolls 40A, 40B is particularly excellent in "softness" and "smoothness". The areas of the recesses and protrusions in the tissue paper are in the range of greater than 1.65 ^mm2 and less than 2.80 ^mm2 , and if the tissue paper has recesses 20 and protrusions 21 with areas slightly smaller than the above range, it can be assumed that they were formed by the embossing rolls 40A, 40B.

The area ratio of the recesses 30 in the embossing rolls 40A and 40B is not necessarily limited, but is preferably 25% or more. When the recesses 20 and protrusions 21 are formed by embossing using the embossing rolls 40A and 40B, the effect of the tissue paper of this embodiment becomes more pronounced. In the embossing process, the recesses and protrusions of the embossing rolls 40A and 40B are transferred to the paper surface, so although they do not match perfectly, the area ratio of the recesses 20 on the tissue paper surface can be roughly estimated by measuring the area ratio of the recesses 30 on the embossing roll.

Furthermore, the height of the convex parts 31 formed on each of the embossing rolls 40A and 40B for forming the concave parts 20 and the convex parts 21 on the tissue paper of this embodiment is preferably more than 0.13 mm and less than 0.35 mm. At this height of the convex parts 31 of the embossing roll, the clearance between the embossing rolls 40A and 40B is adjusted to an appropriate embossing pressure, so that the concave parts 20 and the convex parts 21 are transferred and formed on the paper surface. The height difference between the concave parts and the convex parts of the tissue paper is not necessarily limited, but is preferably in the range of more than 0.13 mm and less than 0.35 mm, which is almost the same as the height of the convex parts 31 of the embossing rolls 40A and 40B. In particular, the difference in the height difference on both surfaces is within 30%, preferably within 10%, and particularly preferably within 5%. Since it is desirable that the tissue paper of this embodiment has no difference in the feeling of use of each surface due to the concave parts and the convex parts, it is desirable that the difference in the height of the concave parts 20 and the convex parts 21 by the embossing process is small on each surface.

The area of the recesses 20 caused by the embossing of the tissue paper and the height difference between the recesses 20 and the protrusions 21 are measured using a "One Shot 3D Shape Measuring Machine VR-3200 (manufactured by Keyence Corporation)" (hereinafter also referred to as "3D Macroscope") and its equivalents (non-contact three-dimensional measuring devices). The "3D Microscope" can measure the shape of an object from a stripe projection image captured by a monochrome C-MOS camera using structured illumination light irradiated from a light projecting section, and in particular, can use the obtained stripe projection image to measure the height, length, angle, volume, area, etc. of any part. The software "VR-H2A" and its equivalents can be used to observe, measure, and analyze the images obtained by the "3D Microscope". The measurement conditions are a field of view area of 24 mm x 18 mm and a magnification of 12 times. When measuring a tissue paper product in which a bundle of tissue paper is stored in a packaging body in a pop-up style, the measurement surface of the sample taken from the bundle of tissue paper is the surface with the fold.

The height difference between the recess 20 and the protrusion 21, and the height difference between adjacent recesses 20 and protrusions 21 are measured. This height difference is obtained by line roughness measurement. The height difference is first displayed as a color image of each point on the image, and the positions of the recess 20 and the protrusion 21 are visually confirmed. An arbitrary recess is selected, and among the protrusions between this recess and multiple adjacent recesses, the protrusion that is located at the highest position relative to the selected recess is selected. Next, a line is drawn across the bottom of the selected recess and the top of the selected protrusion to obtain a line height profile. The difference between the highest point and the lowest point of this line height profile is the height difference. However, taking into account the waviness of the sheet, the inclination correction is set to "automatic correction", and the emboss depth is obtained from the difference between the highest point and the lowest point of the height profile from the profile curve after correction. The measurement is the average value of five points at a position 30% from the outermost end at the start of use, and the value of the emboss height difference is taken as the value of the emboss height difference.

Furthermore, in order to eliminate any difference in the feel of use on each surface, it is desirable that the arrangement of the recesses 20 and protrusions 21 on both surfaces of the tissue paper of this embodiment be the same. Here, with regard to surface properties in particular, it is desirable that the difference in MMD (variation value) between both surfaces be 0.5 or less, and preferably 0.1 to 0.5.

The MMD is measured as follows. The contact surface of the friction element is brought into contact with the surface of the measurement sample to which a tension of 20 g/cm is applied in a predetermined direction with a contact pressure of 25 g, and the friction element is moved 2 cm in approximately the same direction as the tension is applied at a speed of 0.1 cm/s, and the friction coefficient at this time is measured using a friction tester KES-SE (manufactured by Kato Tech Co., Ltd.). The friction element is made of 20 adjacent piano wires P with a diameter of 0.5 mm, and has a contact surface formed so that both the length and width are 10 mm. The contact surface is formed with a unit bulge at the tip formed by 20 piano wires P (radius of curvature 0.25 mm). Note that when measuring the MMD, the contact embossed parts and wrinkled parts are not measured in advance.

On the other hand, since the tissue paper of this embodiment has a multi-ply structure of 3 or more plies, particularly 3 or 4 plies, it is particularly desirable to perform ply crimping processing to crimp the plies together so that the plies do not separate during use. Ply crimping processing is also called knurling processing, edge embossing processing, etc. In particular, considering the multi-use nature, it is desirable to make the product a pop-up type product, and if such a pop-up type product is to be made, it is particularly desirable to perform edge embossing processing. Furthermore, in terms of the basis weight, paper thickness, and number of plies of the tissue paper of this embodiment, it is desirable to form the crimped processing part 23 wider than the width of the conventionally known crimped part in this engine embossing processing. The width L2 is not limited, including whether or not edge embossing is performed, but it is desirable to form the crimped processing part 23 with a width of 3 to 7 mm. This can significantly reduce the risk of ply separation during use. The edge embossing process to form the pressure-bonded portion 23 is preferably performed by applying chemicals using a chemical application means 90, followed by steel match embossing using embossing rolls 40A and 40B, and then by using an edge embossing roll 50, as shown in FIG. 5.

The product form of the tissue paper of this embodiment is not necessarily limited, but it is preferable to make it a pop-up type product in which a folded and stacked bundle is stored in a storage box or wrapped in film. The action and effect of the tissue paper of this embodiment is easily achieved. Another reason is that a pop-up type product is suitable for bathrooms and restrooms with mirrors where makeup and makeup removal are often done. That is, when putting on makeup or removing makeup, in the bathroom or restroom, one may wash his/her hands and wipe the wet hands, then wipe off any moisture that may have adhered to objects, and then wipe his/her face. In such a situation, it is necessary to take out the tissue paper with wet hands, so a pop-up type product is suitable. In such a situation, multiple uses are required, such as "wiping hands" and "wiping objects", and "wiping the face". Therefore, the product form of the tissue paper of this embodiment is preferably a pop-up type product.

The product form 100 of the tissue paper of this embodiment will now be described in detail with reference to the form in which the tissue paper is stored in a storage box in Figures 8 to 10. The storage box 10 in which the stack 1 of tissue paper 2 is stored is a rectangular hexahedral box also known as a carton box. This storage box 10 forms the product's exterior and has a paper box 10A with a circular perforation line on the top surface 10U that forms the removal opening, and a resin film 26 that covers the area surrounded by the perforation line from the inside of the paper box.

The tissue paper 2 stored in a bundle in the storage box 10 is removed one by one from the removal opening 25 through a slit 24 that is exposed by cutting away the area surrounded by the perforation lines. The slit 24 supports the part of the tissue paper 2t exposed from the removal opening 25, preventing it from falling into the carton.

The stack 1 of tissue paper 2 is made by folding and stacking tissue paper 2. More specifically, as can be seen from FIG. 10, the rectangular tissue paper 2 is essentially folded in half, and the folded edge 2e is positioned on the inner fold of the folded tissue paper adjacent above and below, and the tissue paper is stacked in a staggered manner. Note that "essentially" here means that some folding of the edge formed during manufacturing is allowed.

When the topmost folded piece of tissue paper 2 in this stack 1 is pulled upward, the adjacent folded piece directly below is pulled upward by friction and is lifted. The top surface of the stack 1 of tissue paper 2 in this structure is stored in a storage box 10 having an outlet 25 on the above-mentioned top surface 10U, facing said top surface. When the first sheet (the one located on the top surface) is pulled out from said outlet 25, particularly the slit 24, a part of the other sheet located just below it is exposed. Note that the number of layers of tissue paper 2 in this invention is not limited, but an example of the typical number of layers for this type of product is 120 to 240 sheets.

The interfolder that folds the bundle 1 may be a folding plate-based equipment also called a multi-stand type, stand type, or folding plate type, or a pair of folding rolls that fold the bundle 1. In the embodiment, a rotary type interfolder is preferably used. In the case of a tissue paper product with a multi-ply structure of three or more plies, the number of layers is large and the layers are likely to shift, but the rotary type interfolder applies a weaker tension to the continuous sheet than other equipment, so the layers are less likely to shift and the folding quality is easy to improve. Therefore, the "thickness" is less likely to decrease during processing. When folding is performed with a rotary type interfolder, the machine direction (MD) is the pull-out direction. Therefore, when a product that has been folded with a rotary type interfolder is pulled out with wet hands, the wet tensile strength in the machine direction is important, but the tissue paper of this embodiment can achieve this.

[Example of tissue paper manufacturing method]
Furthermore, a preferred method for producing the tissue paper according to this embodiment and a tissue paper product in which the tissue paper is bundled and stored in a package will be described with particular reference to Figs.

First, a primary roll JR (also called a jumbo roll) is manufactured using the papermaking equipment example X shown in Figure 15 as follows.

The pulp slurry is mixed with appropriate chemicals from the head box 31 to prepare a pre-prepared stock, which is then fed onto the wire 32w of the wire part 32 to form a wet paper web SW (forming process), which is then transferred to the felt 33F of the press part 33 and then sandwiched between a pair of dewatering rolls 34, 35 for dewatering (dewatering process).

Next, the dewatered wet paper is attached to the surface of the Yankee dryer 36 and dried, and then scraped off with a doctor blade 37 to produce a dried base paper P1 with crepes (primary continuous sheet, described below) (creping and drying process).

Then, this dried base paper P1 is wound up by a winding means 38 having a winding drum 39 so that the back surface of the dried base paper P1 faces the shaft side of the primary base roll JR (so that it becomes the inner winding surface), to produce the primary base roll JR (primary base roll winding process).

This primary raw roll JR will generally have a diameter of 1,000 to 5,000 mm, a length (width) of 1,500 to 9,200 mm, and a winding length of 5,000 to 80,000 m, although this will vary depending on the performance of the papermaking equipment X.

In addition, a calendaring process (not shown) may be performed on the dried base paper P1 that has been scraped off by the doctor blade 37 prior to the primary base paper winding process to smooth the front and back surfaces.

Here, the back surface of the dried base paper P1 means the surface opposite to the surface that was in contact with the cylinder of the Yankee dryer 36. Although it depends on whether or not a calendaring process is performed, the surface that was in contact with the mirror-finished Yankee dryer is generally smoother and has better surface properties.
As described above, at least the outer surface (exposed surface) of the outer layer of the laminated sheet is the surface that was in contact with the Yankee dryer with a mirror surface (smooth and excellent surface), and it is preferable to apply a moisturizing agent to this smooth and excellent surface. This makes it possible to make the outer surface (exposed surface) of the outer layer smooth. As a result, the laminated sheet gives consumers a smooth and soft feel when used.

The primary continuous sheet P1 has a crepe rate of 10 to 30%, preferably 12 to 25%, and more preferably 13 to 20%. If the crepe rate is less than 10%, the tissue paper 2 will be easily broken during subsequent processing and will have little stretch and stiffness. On the other hand, if the crepe rate exceeds 30%, it will be difficult to control the tension of the sheet during processing, making the tissue paper 2 prone to breaking, and after production, combined with moisture absorption by the moisturizing agent, wrinkles will occur, making the tissue paper 2 more likely to look unattractive.

Three primary raw rolls JR (four in the case of four plies) produced in the papermaking process are set in an interfolder, and a single layer of continuous sheet is unwound from each primary raw roll, and a moisturizing agent is applied to it, for example, using the application method described below.

In the case of three plies, the moisturizer is applied to each of the single-layer continuous sheets, or the single-layer continuous sheets are stacked in two layers and the moisturizer is applied to both sides of the two layers, and the other layers are single-layered. In the case of four plies, the moisturizer is applied to each of the single-layer continuous sheets, or the single-layer continuous sheets are stacked in two layers and the moisturizer is applied to both sides of the two layers, and similarly, the other single-layer continuous sheets can be stacked in two layers and the moisturizer can be applied to both sides of the two layers.

After the moisturizing agent is applied, the laminated continuous sheet can be calendered. There are no particular limitations on the type of calender, but a soft calender or chilled calender is preferred for the reasons of improving surface smoothness and adjusting the paper thickness. A soft calender is a calender that uses a roll covered with an elastic material such as urethane rubber, and a chilled calender is a calender made of a metal roll.

The number of calendar sections can be changed as appropriate. Installing multiple calendar sections has the advantage that sufficient smoothing can be achieved even at high processing speeds, while only one has the advantage that it can be installed in a small space. The type of calendar, nip line pressure, number of nips, etc. in the calendar process are also used as control factors in papermaking, and it is preferable to change these control factors as appropriate depending on the desired quality of the tissue paper, i.e., paper thickness and surface properties.

Then, as shown in Figure 6, a steel match embossing process is performed. This integrates the laminated sheets, improves the design, and achieves the effects of the embodiment.

The folding process is carried out immediately following the moisturizing liquid application process and the steel match embossing process. In this folding process, the obtained laminated sheet is folded in sequence in a folding device known as a rotary interfolder (not shown) in such a way that one side of the preceding laminated sheet and one side of the succeeding laminated sheet are inserted into the valley fold of the laminated sheet, and the laminated sheets are stacked into a bundle.

The stack of laminated sheets is cut into short bundles of a specified length, and these short bundles of laminated sheets are stored in a package (paper packaging box, plastic packaging bag, etc.), so that when used, the laminated sheets can be removed one by one from the package in a pop-up manner.

The moisturizing liquid can be applied using a roll transfer device such as a flexographic printer or a gravure printer, or a spray application device.

When applying an aqueous moisturizing liquid containing glycerin as the main component, which exhibits hygroscopic properties, and when applying to a sheet traveling at high speed, flexographic printing or spray application is particularly preferred.

If the chemicals are applied using the flexographic printing method, there are advantages to using a resin printing plate roll (transfer roll) that can accommodate the unevenness of the crepe paper and stabilize the amount of coating, even when the processing speed is high. There are also advantages to changing the line count and cell capacity of the anilox roll, and the line count and apex area ratio of the flexographic printing plate roll, which can easily accommodate a wide range of chemical viscosities and stabilize the amount of coating.

In addition, it is preferable to use a flexographic printing method using a doctor chamber for the chemical application process. The doctor chamber method applies the chemical directly to the surface of the anilox roll (concave transfer roll) to create a film, and has the advantage that the chemical is less likely to be contaminated by paper powder or air, making the physical properties of the chemical stable. In addition, the chemical transferred from the anilox roll is uniform, so it can be applied effectively even in the case of a small amount of coating.

The illustrated example shows a flexographic printing machine used as the chemical application means 90 in the chemical application process. When applying chemicals to a laminated continuous sheet, it is particularly desirable for the flexographic printing plate roll to be made of silicone rubber. The number of lines of the flexographic printing plate roll is 10 to 60 lines, preferably 15 to 40 lines, and particularly preferably 20 to 35 lines. If the number of lines is less than 10 lines, coating will be uneven, while if the number of lines is more than 60 lines, paper dust will easily clog.

The number of lines of the anilox roll is 10 to 300 lines, preferably 25 to 200 lines, and particularly preferably 50 to 100 lines. If the number of lines is less than 10 lines, coating unevenness will occur, while if the number of lines is more than 300 lines, paper dust will easily clog. The cell capacity of the anilox roll is 10 to 100 cc, preferably 15 to 70 cc, and particularly preferably 30 to 60 cc. If the cell capacity is less than 10 cc, the desired coating amount will not be obtained, while if the cell capacity is more than 100 cc, the amount of chemical solution splashing will be large.

Here, it is important that the chemicals can be applied stably in the chemical application process, and the line count of the printing plate roll and the anilox roll, which are related to operational stability, is important. In addition, the method of transferring the chemicals stored in the storage tank to the anilox roll can be appropriately selected, such as the doctor chamber method or the touch roll method. Examples of forms that adopt each of these flexographic printing methods are described in detail below.

In the doctor chamber type flexographic printing machine 90 for flexographic printing, a doctor chamber 92 containing a chemical solution is arranged opposite a rotatable anilox roll 93, and the chemical solution is transferred from the doctor chamber 92 to the anilox roll 93. In addition, a printing plate (transfer) roll 94 that contacts the anilox roll 93 and the sheet P1 or P2 is rotatably installed, and the chemical solution is transferred from the anilox roll 93 to the printing plate roll 94. Then, while applying pressure between the printing plate roll 94 and an elastic roll 95 that faces the printing plate roll 94 with the sheet P1 or P2 sandwiched between them, the printing plate roll 94 applies the chemical solution to the laminated continuous sheet. As described later, the elastic roll 95 can be used or not used, and the printing plate (transfer) roll 94 can be placed opposite each other and pressure can be applied between them to apply the chemical solution to the laminated continuous sheet from the printing plate roll 95.

A suitable example of controlling the amount of moisturizer applied is to base it on the degree of difference in peripheral speed of the anilox roll 93 relative to the printing plate roll 94, since this allows the amount of moisturizer applied to be controlled during the operation process.

<First Moisturizing Agent Application Form>
Various types of moisturizing agent application forms can be adopted. Figure 16 shows a three-ply moisturizing agent application form, in which the monolayer sheet unwound from three primary rolls is fed to an application device having three flexographic printers 90, with the two-layer sheet P2, which merges into two layers along the way, and the monolayer sheet P1 as is. The chemical solution is applied to each outer surface of the two-layer sheet P2. The chemical solution is also applied to the outer surface of the monolayer sheet P1. The two-layer sheet P2 and the monolayer sheet P1 are merged at a merging portion 50 to form a three-layer laminated sheet P3. Thereafter, as described above, the sheets are passed through a steel match embossing process and guided to an interfolder.

Figure 17 shows another three-ply moisturizer application form, where the single-layer sheet unwound from the three primary rolls merges with the three-layer sheet along the way, and is separated into a two-layer sheet P2 and a single-layer sheet P1 at a separation section 51, and is supplied to an application device having three flexographic printers 90. The chemical solution is applied to each outer surface of the two-layer sheet P2. It then merges with the single-layer sheet P1 at the merging section 50 to form a three-layer sheet, and the chemical solution is then applied to the outer surface of the single-layer sheet P1 by another flexographic printer 90, forming a three-layer laminated sheet P3.

Figure 18 shows a four-ply moisturizer application form, where two single-layer sheets unwound from four primary rolls join together along the way to form a two-layer sheet, and the chemical solution is applied to each outer surface of the two-layer sheet P2. Similarly, the other two single-layer sheets join together along the way to form a two-layer sheet, and the chemical solution is applied to each outer surface of the two-layer sheet P2. The two-layer sheets P2 then join together at the joining point 50 to form the four-layer laminated sheet P4.

<Second Moisturizing Agent Application Form>
A sheet coated with a water-based moisturizer (chemical solution) containing glycerin as a main component, which exhibits hygroscopicity, tends to elongate and lose strength. When this coating is performed particularly at high speed, in the first moisturizer coating form, there is a so-called free-run portion in which the sheet is not restrained by anything between each coating position. As a result, a sheet coated with a water-based moisturizer (chemical solution) elongates and loses strength, causing the sheet to break. In contrast, it is preferable to use a second moisturizer coating form, that is, a coating form in which at least each sheet is in contact with a roll traveling at the same speed as the sheet, during the course from each chemical solution coating position to the three-ply stacking position.

Figure 19 shows an example of the second moisturizer application form for three plies, in which each flexographic printer 90 does not have an elastic roll 95 as in the first moisturizer application form. Instead, the sheet is nipped between the printing plate (transfer) roll 94 of the first flexographic printer 90A and the printing plate (transfer) roll 94 of the second flexographic printer 90B, and the sheet is nipped between the printing plate (transfer) roll 94 of the second flexographic printer 90B and the printing plate (transfer) roll 94 of the third flexographic printer 90C. The two-layer sheet P2 is coated with a chemical solution from both sides by the first flexographic printer 90A and the second flexographic printer 90B, and then the chemical solution is applied to the outer surface of the single-layer sheet P1 by the third flexographic printer 90C.

Figure 20 shows an example of the second moisturizer application form of 4 plies. As shown in the figure, the sheet is nipped between the printing plate (transfer) roll 94 of the first flexographic printing machine 90A and the printing plate (transfer) roll 94 of the second flexographic printing machine 90B, the sheet is nipped between the printing plate (transfer) roll 94 of the second flexographic printing machine 90B and the printing plate (transfer) roll 94 of the third flexographic printing machine 90C, and the sheet is nipped between the printing plate (transfer) roll 94 of the third flexographic printing machine 90C and the printing plate (transfer) roll 94 of the fourth flexographic printing machine 90D. The two-layer sheet P2 has a chemical solution applied to both sides by a first flexographic printer 90A and a second flexographic printer 90B, while the other two-layer sheet P2 has a chemical solution applied to both sides by a fourth flexographic printer 90D and a third flexographic printer 90C, which then join together to form four-layer P4.

Figure 21 shows another example of the second moisturizing agent application form for 4 plies. As shown in the figure, the sheet is nipped between the printing plate (transfer) roll 94 of the first flexographic printing machine 90A and the printing plate (transfer) roll 94 of the second flexographic printing machine 90B; the sheet is nipped between the printing plate (transfer) roll 94 of the second flexographic printing machine 90B and the printing plate (transfer) roll 94 of the fourth flexographic printing machine 90D; and the sheet is nipped between the printing plate (transfer) roll 94 of the second flexographic printing machine 90B and the printing plate (transfer) roll 94 of the third flexographic printing machine 90C. At these nip positions, the chemical solution is applied to both sides of the two-layer sheet P2, the single-layer sheet P1 that will be the middle sheet, and the single-layer sheet P1 that will be the outer layer sheet.

<Third moisturizer application form>
As the third moisturizing agent application form, spray application is also possible.Specifically, spray application can adopt nozzle type spray method, rotor dampening spray method, etc.The type of the spray nozzle in the nozzle type spray method includes an empty cone type nozzle that sprays in an annular shape, a full cone type nozzle that sprays in a circular shape, a full pyramid type nozzle that sprays in a square shape, a full rectangular nozzle, a fan nozzle, etc., and the nozzle diameter, the number of nozzles, the nozzle arrangement pattern, the number of nozzles arranged, or the spray distance, the spray pressure, the spray angle, and the concentration, viscosity, etc. of the spray liquid can be appropriately selected and used so that the chemical solution is sprayed uniformly in the width direction of the secondary continuous sheet.

In addition, nozzle-type sprayers can use two types of atomization methods: a one-fluid method or a two-fluid method. In the one-fluid spray method, compressed air is used to directly apply pressure to the medicinal liquid to be sprayed, spraying the mist from the nozzle, or air is sucked into the nozzle through a fine hole opened in the side of the nozzle near the outlet, spraying the mist. In addition, two-fluid spray methods include an internal mixing type in which compressed air is mixed with the liquid to be sprayed inside the nozzle and atomized, an external mixing type in which compressed air is mixed with the liquid to be sprayed outside the nozzle and atomized, and a collision type in which atomized mist particles are collided with each other to further homogenize and atomize the mist particles.

On the other hand, the rotor dampening spray method sends the liquid to be sprayed onto a rapidly rotating disk, and the centrifugal force of the disk breaks the liquid into fine mist droplets. The mist droplet size is controlled by changing the rotation speed of the disk, and the amount of liquid sprayed (amount applied) is controlled by changing the amount of liquid sent onto the disk. Rotor dampening applicators have the advantage that they can apply a small amount of spray liquid evenly to the surface of pigment coated paper while suppressing the scattering of mist droplets, and that it is easy to adjust the spray speed, mist droplet size, etc.

Figure 22 shows an example of a rotor dampening spray device 200. This is a device in which a rotating rotor 200A is provided in a cover storage chamber (not shown) that is provided as needed, and the chemical solution is sprayed onto a laminated continuous sheet from the nozzle 200B of the rotating rotor. An embodiment of obtaining a three-ply laminated sheet using the rotor dampening spray device 200 is shown in Figures 23 and 24. The application form will be immediately apparent without further explanation.

Samples of tissue paper according to the embodiment and tissue paper according to the comparative example were prepared, and the following sensory tests were conducted for each item in the sensory test column as an evaluation item. Comparative Examples 1 to 3 are non-moisturizing tissues. Comparative Examples 4 and 5 are moisturizing tissues to which a moisturizing solution has been applied. The physical properties and composition values of each sample were measured as follows. The physical properties and composition values and test results of each sample are shown in Table 1. The measurement methods for basis weight, paper thickness, dry tensile strength, wet tensile strength, flexibility, MMD, area of recesses, and height difference were as described above.

The embossing in each example was performed using the same embossing roll. Therefore, the formation arrangement of the concaves and convexes was the same. The embossing was steel match embossing. The area of the concaves in the tissue paper in the examples was more than 1.65 ^mm2 and less than 2.80 ^mm2 , the number of concaves or convexities by the embossing was 15 to 17 per ^cm2 on one side, the height difference between the concaves and convexities was more than 0.13 mm and less than 0.35 mm on each surface, and the total area ratio of the concaves on one side was adjusted to 25% or more. Some numerical values differ from those of the comparative examples.

[Sensory Test]
The score is the average of scores from 1 to 5 given by 20 evaluators. The sensory evaluation test was conducted by placing the sample (tissue paper) according to each example in the washroom, and having subjects freely wet their hands with water, place it around their face, wipe the skin or objects that had become wet with water, and then rating the items of "softness,""firmness," and "ease of wiping between hands." The higher the score, the higher the evaluation.

上記結果によれば、実施例１～実施例８は、総合評価が比較例と比して、高い評価となっている。特に「柔らかさ」と「しっかり感」と「手の間の拭き取りやすさ」の評価がバランスよく高くなっており、「手拭き」、「物品の拭き取り」用途に適しつつ、「顔拭き」にも不満なく使用できるといえ、マルチユースに対応できる。特に、実施例２～実施例７の範囲の評価が高い。非保湿の比較例１～比較例２は、４プライの多プライであるが坪量が低い。比較例３は、坪量が本発明と同程度で３プライとなっているが、乾燥引張強度が過度に高い。比較例１～比較例２は、「手の間の拭き取りやすさ」の評価は十分であるが、「柔らかさ」と「しっかり感」が十分ではない。特に「しっかり感」が十分ではない。他方で比較例３は、「しっかり感」は十分であるが「柔らかさ」が十分ではない。つまり、比較例１～比較例３は、「手拭き」用途に適しながらマルチユースに対応できていない。他方で、比較例４及び比較例５は、保湿ティシューであるが、「柔らかさ」は十分であるが「しっかり感」が十分に発現されていない。つまり、「顔拭き」等には適するが「手拭き」や「物品の拭き取り」には不十分であり、マルチユースに適していない。
以上のことから、本発明によれば、「しっかり感」に優れ、強度も十分であり、「手拭き」用途に適しつつ、顔の拭き取りにも十分な「柔らかさ」もあって、マルチユースにも使用しやすいティシュペーパーが提供される。

According to the above results, the overall evaluation of Examples 1 to 8 is higher than that of the comparative examples. In particular, the evaluations of "softness", "firmness" and "ease of wiping between hands" are well balanced and high, and while it is suitable for "hand wiping" and "wiping off objects", it can also be used without complaint for "face wiping", and can be used for multi-use. In particular, the evaluations of the range of Examples 2 to 7 are high. The non-moisturizing Comparative Examples 1 and 2 are multi-ply with 4 plies, but have a low basis weight. Comparative Example 3 has a basis weight of about the same as the present invention and is 3 plies, but the dry tensile strength is excessively high. Comparative Examples 1 and 2 are sufficient in the evaluation of "ease of wiping between hands", but "softness" and "firmness" are not sufficient. In particular, the "firmness" is not sufficient. On the other hand, Comparative Example 3 has a sufficient "firmness" but not sufficient "softness". In other words, Comparative Examples 1 to 3 are suitable for "hand wiping" use, but are not suitable for multi-use. On the other hand, Comparative Examples 4 and 5 are moisturizing tissues, and although they have sufficient "softness", they do not fully express "firmness". In other words, they are suitable for "wiping the face" etc., but are insufficient for "wiping hands" or "wiping objects", and are not suitable for multi-use.
As described above, the present invention provides tissue paper that is excellent in "firmness," has sufficient strength, and is suitable for "hand wiping," while also being "soft" enough for wiping the face, making it easy to use for multiple purposes.

2...tissue paper, 1...bundle, 10...storage box, 10U...upper surface, S1-S4...sheets (plies), A1-A3...raw roll, S...processed base paper, 24...slit, 25...outlet, 20...recess, 20B...bottom, 21...protrusion, 21t...top, 22...slope, 40A, 40B...embossing roll, L...imaginary line, ∠α...angle between imaginary line L and the longitudinal direction of the paper, 23...pressing section, L2...width of pressing section, 50...edge embossing roll, 100...tissue paper product. 90...chemical application means, 200...rotor dampening spray device, F...coated surface, P1-P4...sheets (plies), W...non-coated surface.

Claims (7)

A tissue paper having three or more plies,
The basis weight of each layer is greater than 17.8 g/ ^m2 and less than 26.0 g/ ^m2 ;
The thickness of the product ply is more than 350 μm and less than 570 μm,
The wet tensile strength in the longitudinal direction is more than 750 cN/25 mm and less than 1250 cN/25 mm, and the wet tensile strength in the transverse direction is more than 190 cN/25 mm and less than 400 cN/25 mm;
The moisturizing agent contains 70% or more of glycerin and is 3.5% or more and less than 16.5% by mass.
The two surfaces have concave and convex portions formed by embossing, and the concave portions on one surface correspond to the convex portions on the other surface.
The pattern of the concave and convex portions in plan view is a pattern in which the concave and convex portions are arranged at intersection positions of a lattice.
The tissue paper is characterized by the above. The tissue paper according to claim 1, having a water absorption of 612 g/ ^m2 or more and a softness of more than 250 mN and less than 440 mN. 2. The tissue paper according to claim 1, wherein the number of recesses and protrusions per square centimeter on one side is 15 to ¹⁷ . a steel match embossing process is performed by using a pair of embossing rolls, in which a recess formed on a surface of one embossing roll fits with a protrusion formed on a surface of the other embossing roll, and a protrusion formed on the surface of the one embossing roll fits with a recess formed on a surface of the other embossing roll,
The tissue paper according to claim 1, wherein the areas of the recesses and protrusions in the embossing rolls are greater than 1.65 ^mm2 and less than 2.80 ^mm2. The tissue paper according to claim 4, wherein the height of the convex portion of the embossing roll is more than 0.13 mm and less than 0.35 mm. The tissue paper according to claim 4 or 5, in which the area ratio of the recesses of the embossing roll is 25% or more. A tissue paper product in which the tissue paper according to any one of claims 1 to 6 is folded and stacked to form a pop-up bundle, and the bundle is placed in a storage box or a packaging film.

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