JP2024072247A - Tissue paper and tissue paper products - Google Patents

Abstract

[Problem] To provide a tissue paper that is sufficiently soft and absorbent for wiping the face, and is also suitable for multiple uses. [Solution] The problem is solved by a tissue paper that is non-moisturizing and has 3 or more plies, each ply having a basis weight of more than 13.9 g/m2 and less than 17.1 g/m2, an overall paper thickness of more than 305 μm and less than 415 μm, and has concave and convex portions embossed on both surfaces, with the concave portions on one surface becoming the convex portions on the other surface, and the pattern of the concave and convex portions in plan view being a pattern in which the concave and convex portions are arranged at the intersections of a lattice. [Selected Figure] Figure 1

Description

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

One type of tissue suitable for wiping the face, such as blowing your nose or touching up your makeup, is moisturizing tissue, which contains a chemical solution that gives the tissue paper moisturizing properties. This moisturizing tissue has a high moisture content due to the moisture absorption action of the moisturizing agent, which makes it easy to feel good about the "touch" such as "softness" and "smoothness."

Conventionally, some tissue papers suitable for wiping the face have been given unevenness through embossing. The unevenness created by embossing creates patterns such as floral designs on the surface of the tissue paper, enhancing the design and giving the user the impression that the tissue paper is suitable for use in contact with the face. This type of embossing is often in the form of a type called single embossing. With single embossing, there are only recesses on one side and only protrusions corresponding to the recesses on the other side.

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 the face. In areas where multiple uses are assumed, there is a demand for tissue paper that is easy to use for wiping the face, hands, and objects, and that offers an improved usability for specific uses, such as wiping the face.

Patent No. 5978100 Patent No. 5883412

However, because moisturizing tissues have a high moisture content, they have the following drawbacks: they have a low water absorption capacity to begin with, they tear easily when touched with wet hands, they have a poor sense of thickness, and absorbed moisture easily seeps through to the other side. For this reason, conventional moisturizing tissues are not suitable for use in places where there is water, such as washbasins, and even when used to wipe the face, they are not necessarily suitable for certain situations and times, such as wiping off moisture or medicines that have adhered to the skin when touching up makeup.

In addition, when used for wiping the face, there is a need for little difference in quality between both sides; in other words, no matter which side is used for wiping, there should be little difference in the characteristics required for wiping the face, such as "softness" and "smoothness" in "touch" and absorbency. However, with conventional embossed tissue paper, particularly single embossed tissue paper, only recesses are formed on one side and corresponding protrusions are formed on the other side, resulting in a large difference in quality between the two surfaces.

As described above, there has been no conventional tissue paper that is particularly excellent for wiping the face and also easy to use for multiple purposes. Therefore, the main objective of the present invention is to provide a tissue paper that is sufficiently "soft" and "absorbent" for wiping the face, and is also suitable for multiple uses.

The first means according to the present invention for solving the above problem is:
A non-moisturizing tissue paper having three or more plies,
The basis weight of one ply is more than 13.9 g/ ^m2 and less than 17.1 g/ ^m2 ,
The total paper thickness is more than 305 μm and less than 415 μm,
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
Wet tensile strength in the longitudinal direction is greater than 200 cN/25 mm and less than 410 cN/25 mm;
The wet tensile strength in the transverse direction is greater than 75 cN/25 mm and less than 172 cN/25 mm;
This is the tissue paper according to the first aspect.

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 greater 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 according to the first or second aspect has the same arrangement of recesses and projections on both surfaces, and the difference in MMD value (variation value) between both surfaces is 0.5 or less (0.1 to 0.5).

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

The present invention provides tissue paper that is soft enough and absorbent enough for face wiping, and is also suitable for multiple uses.

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. 1 is a graph showing the results of sensory evaluation of Comparative Examples and Examples.

The present invention will be further described below with reference to embodiments thereof.
An embodiment of the tissue paper 2 having three or four plies laminated therein 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 the three-ply tissue, and FIG. 4 shows a cross-sectional view of the four-ply tissue. First, since the tissue paper has three or four plies instead of two plies, it is suitable for use in contact with the skin, particularly for wiping the face, while being easy to feel a "thickness" and "firmness," and is sufficient for other general uses such as wiping objects and wiping hands, and is unlikely to cause anxiety or dissatisfaction even when used for multiple purposes. The three-ply tissue is a form in which three plies (sheets) S1 to S3 are laminated, and the four-ply tissue is 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 13.9 to 17.1 g/m ² , preferably 14.0 to 16.5 g/m ² , and particularly preferably 14.3 to 15.2 g/m ^2. When the basis weight of each layer is within this range, the recesses and protrusions caused by the embossing of this embodiment described below are well formed, and in combination with the recesses and protrusions caused by the embossing, the "softness" is significantly exhibited.

Here, the basis weight is thought to have a large effect on "softness," since a high basis weight makes the paper harder, and a low basis weight makes it softer. At this basis weight, "3-ply or 4-ply" provides a noticeable "softness" without any complaints about multi-use such as "thickness" or "firmness," making it particularly suitable for face wiping. The basis weight is a value measured based on JIS P 8124 (1998).

The overall paper thickness of the tissue paper of this embodiment is more than 305 μm and less than 415 μm. It is preferably 313 to 412 μm, and particularly preferably 340 to 373 μm. 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, "softness" and "thickness" are prominent, and combined with the unevenness caused by the embossing process, "smoothness" is also prominent.

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.

The thickness of the tissue paper of this embodiment when ten sheets are stacked is preferably more than 3.5 mm and less than 4.8 mm, and more preferably 3.6 mm to 4.7 mm. The measured value for ten sheets is less affected by crushing of the embossing. When the paper thickness is within this range, as well as the range for one sheet above, the "softness" and "thickness" become prominent, and combined with the unevenness caused by the embossing, the "smoothness" also becomes prominent. The measurement method is the same as the measurement method for one sheet above, except that 10 sheets are stacked and measured.

The tissue paper of this embodiment is a non-moisturizing tissue paper. That is, a moisturizing agent that enhances moisture absorption is not externally applied. Since it does not contain a moisturizing agent that enhances moisture absorption, the moisture content is low and the amount of water absorption is large. Here, the water absorption of the tissue paper of this embodiment is not necessarily limited, but if the amount of water absorption is 640 g/ ^m2 or more, it can be said that the tissue paper has a water absorption amount that is excellent in terms of wiping the skin while having multi-use properties. In the tissue paper of this embodiment, this amount of water absorption can be achieved by combining the unevenness caused by the embossing process, the number of plies, the paper thickness and the basis weight. The amount of water absorption is measured as follows. The test environment is 23°C and humidity 50%. The test piece is cut to 100 mm x 100 mm (±0.5 mm). The test liquid is tap water at room temperature. A tray is prepared to hold the test piece 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 liquid, 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.

In addition, the wet tensile strength of the tissue paper of this embodiment with three or four plies in the longitudinal direction is preferably more than 200 cN/25 mm and less than 410 cN/25 mm. More preferably, it is 209 cN/25 mm or more and 399 cN/25 mm or less, and particularly preferably, it is 211 cN/25 mm or more and 364 cN/25 mm or less. In addition, the wet tensile strength in the transverse direction is preferably more than 75 cN/25 mm and less than 172 cN/25 mm. More preferably, it is 77 cN/25 mm or more and 162 cN/25 mm or less, and particularly preferably, it is 101 cN/25 mm or more and 157 cN/25 mm or less. Note that this value is measured when each ply is stacked, i.e., when the three or four plies are still stacked. Wet strength is related to the strength when absorbing moisture, such as when blowing nose, when absorbing lotion when removing makeup, when popping up and taking out with wet hands, when wiping off moisture on an object, etc. In combination with other configurations, this range allows for a pop-up type tissue paper product that feels "soft" when touching the skin, especially the face, and can be pulled out horizontally without breaking, even when pulled out with wet hands, making it suitable for a variety of uses, i.e., multi-use, while being specialized for use in contact with the skin. The lengthwise direction of the paper is also called the MD direction, and is the flow direction during papermaking. The widthwise 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 pulling 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 immediately a tensile load is 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 603 cN/25 mm or more and 1223 cN/25 mm or less, and particularly preferably 623 cN/25 mm or more and 1103 cN/25 mm or less. If the dry strength in the longitudinal direction is within this range, the "softness", "thickness" and "smoothness" will be remarkable. In addition, it is within a range of sufficient strength to withstand use. 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, the softness will be inferior and it will be difficult to sufficiently loosen the fibers when forming unevenness by embossing processing according to the present invention described below.

In addition, the dry tensile strength of three or four plies in the horizontal direction is preferably 227 cN/25 mm or more and 593 cN/25 mm or less, and particularly preferably 264 cN/25 mm or more and 412 cN/25 mm or less. When the dry strength in the horizontal direction is within this range, the "softness", "thickness" and "smoothness" become prominent. In addition, it is within a range of sufficient strength to withstand use. Furthermore, although it is not certain, the "dry tensile strength in the horizontal direction" affects the overall sensory sensation of "touch" rather than individual sensory sensations such as "softness" and "thickness". When subjects are allowed to freely touch the sample and then asked to evaluate the tissue paper as "good" or "bad" using the overall evaluation criterion of "touch", rather than specific evaluation criteria such as "softness" and "thickness", it has been found that there is a certain correlation between the evaluation of "touch" and the "dry strength in the horizontal direction".

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 fiber material that makes up the tissue paper is pulp fiber, and is preferably NBKP (softwood 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 highly 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 allows the paper to have the necessary paper strength and "thickness" for multiple uses while also giving a noticeable sense of "softness" and "smoothness."

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 properties such as basis weight and paper thickness, and has the recesses 20 and protrusions 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 recesses and protrusions allows both surfaces to have almost the same wiping properties. In this way, since both surfaces can be used with the same quality, it is particularly suitable for 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 protrusions. In addition, since the contact area with the skin is small, it has excellent slipperiness and is easy to feel "smoothness". Furthermore, when pressed against the skin, the cushioning properties of the protrusions make it easy to feel "thickness" and "fluffiness". Furthermore, the pattern of the arrangement of the recesses and protrusions is such that the recesses 20 and protrusions 21 are alternately positioned at a constant rate in the vertical and horizontal directions on both surfaces, so that the roughness caused by the protrusions 21 is hard to feel, and as a result, it is easier to feel "smoothness". Furthermore, because the paper surfaces on both sides are uneven, it gives a sense of thickness that gives a sense of security when wiping items other than the skin, and is also excellent at wiping and scraping off dirt and dust.

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, makes it particularly suitable for use in contact with the skin, as it is non-moisturizing but has "softness," "absorbency," and "smoothness," while also being fully compatible with other general uses, i.e., multi-use.

Here, the softness of the tissue paper of this embodiment is not necessarily limited, but it is desirable that the softness is more than 70 mN and less than 128 mN. More preferably, it is 71 mN or more and 123 mN or less, and particularly preferably, it is 90 mN or more and 114 mN or less. When the softness is in the range of more than 70 mN and less than 128 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 means of embossing 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 such as metal. Figure 6 shows a three-ply embodiment in which sheets S1, S2, and S3 are paid out from three raw rolls A1, A2, and A3 and 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, 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 coarsened. This makes it easier to improve the smoothness of the top 21t of the protrusion 21 that touches the skin, and to obtain cushioning properties for the entire protrusion, and the effects of the tissue paper of this embodiment, which is particularly suitable for skin-contact applications such as the above-mentioned "softness," "absorbency," and "smoothness," while also being fully compatible with other general uses, i.e., multi-use, become more pronounced. In particular, the smoothness and cushioning effects achieved by the coarse and dense fibers at the bottom 20B (top 21t) of the recess 20 (protrusion 21) and the slope 22 in this steel match embossing are also related to the fiber ratio of NBKP:LBKP described above, especially the high blending ratio of LBKP. In other words, the above NBKP:LBKP and steel match embossing process produce a greater effect.

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 oval, 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 this range, it can be assumed that they were formed by the above-mentioned 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 formed by the embossing of the tissue paper, the height difference between the recesses 20 and the protrusions 21, etc. 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 the 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 the value. These measurements are performed with N=5, and the average value is the height difference.

Furthermore, in order to eliminate any difference in the feel of the tissue paper 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 three or more plies, particularly three or four 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 of the tissue paper, 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 for this embossing processing to form the crimped part 23 wider than the width of the conventionally known crimped part. The width L2 is not limited, including whether or not edge embossing is performed, but it is desirable to form the crimped part 23 with a width of 3 to 7 mm. This significantly reduces the risk of ply separation during use.

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 applying makeup or removing makeup, in the bathroom or restroom, one may wash his or her hands and wipe the wet hands, then wipe off any moisture that may have adhered to objects, and then wipe the 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 addition, in such a situation, multi-use properties are required, mainly for wiping the face, as well as for wiping hands and wiping objects. 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 22 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) in which the paper strength is strong becomes 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 this is sufficient with the tissue paper of this embodiment.

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 the evaluation item. Comparative Example 4 and Comparative Example 5 are moisturized 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 the scores from 1 to 5 given by 20 evaluators. The higher the score, the higher the evaluation. The sensory evaluation test was performed by placing the sample (tissue paper) of each example in the washroom, and having the subject freely wet his/her hands with water, place it around his/her face, wipe the wet area of the skin or object, etc., and rating the items of "softness,""firmness,""ease of wiping off water from the face," and "difference in texture between the front and back sides." In addition, for "difference in texture between the front and back sides," a higher score was given to a sample with no difference in texture between the front and back sides.

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、実施例２～実施例７の範囲の評価が高い。この評価にかんして、図１１にグラフ化すると、本発明ではない非保湿の比較例１～比較例３は、３プライであっても４プライであっても「しっかり感」の評価は高いものの「柔らかさ」、「顔についた水の拭き取り易さ」の評価が低い。物品の拭き取り等には適するものの肌、特に顔に触れる用途において適していないことが示されている。特に、非保湿でありながら水分の拭き取りに適していないことが示されている。他方で、本発明ではない保湿ティシューである比較例４および比較例５は、３プライ同士で比較すると「柔らかさ」については、本発明の実施例１及び実施例２と同程度であるが、「しっかり感」が低く、保湿で水分率が高いため、顔についた水の拭き取り易さ」の評価がさほど高くない。本発明の実施例１～実施例８は、比較例と異なり、各官能評価の折れ線が密に示されており、特に「柔らかさ」及び「顔についた水の拭き取り易さ」の評価が高い。すなわち、「柔らかさ」及び「顔についた水の拭き取り易さ」に優れているともに「しっかり感」も感じられ、「表面と裏面の肌触りの違い」も感じ難い。したがって、本発明によれば、「柔らかさ」、「吸水性」に優れ、各表面の肌触りの差がなく、顔の拭き取り用途に適しつつ、「しっかり感」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 evaluation of the range of Examples 2 to 7 is high. Regarding this evaluation, when graphed in FIG. 11, the non-moisturizing Comparative Examples 1 to 3, which are not the present invention, are high in the evaluation of "firmness" whether they are 3-ply or 4-ply, but low in the evaluation of "softness" and "ease of wiping off water from the face". It is shown that although they are suitable for wiping off objects, they are not suitable for use in contact with the skin, especially the face. In particular, they are not suitable for wiping off water, despite being non-moisturizing. On the other hand, the moisturizing tissues of Comparative Examples 4 and 5, which are not the present invention, are comparable in "softness" to Examples 1 and 2 of the present invention when compared with each other using 3-ply, but are low in "firmness" and have a high moisture content due to moisturizing, so the evaluation of "ease of wiping off water from the face" is not very high. Unlike the comparative examples, the broken lines of each sensory evaluation are densely shown for Examples 1 to 8 of the present invention, and the evaluations of "softness" and "ease of wiping off water from the face" are particularly high. That is, it is excellent in "softness" and "ease of wiping off water from the face", while also having a "firm feel" and little sense of "difference in texture between the front and back sides". Therefore, according to the present invention, tissue paper is provided that is excellent in "softness" and "water absorbency", has no difference in texture between the two sides, is suitable for wiping the face, and has a "firm feel" that makes 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 rolls, S...processed raw 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 vertical direction of the paper, 23...pressed section, L2...width of pressed section, 100...tissue paper product.

Claims (8)

A non-moisturizing tissue paper having three or more plies,
The basis weight of one ply is more than 13.9 g/ ^m2 and less than 17.1 g/ ^m2 ,
The total paper thickness is more than 305 μm and less than 415 μm,
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. Wet tensile strength in the longitudinal direction is greater than 200 cN/25 mm and less than 410 cN/25 mm;
The wet tensile strength in the transverse direction is greater than 75 cN/25 mm and less than 172 cN/25 mm;
The tissue paper according to claim 1. 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 on 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. The tissue paper according to claim 1 or 2, in which the arrangement of the recesses and protrusions on both surfaces is the same, and the difference in the MMD values on both surfaces is 0.5 or less. A tissue paper product in which the tissue paper according to any one of claims 1 to 7 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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