Toilet roll and method for manufacturing same

Abstract

Toilet roll of three or more plies that has good texture and is not easily torn and method for manufacturing same SOLUTION: A multi-ply toilet roll having three or more plies, in which a basis weight per sheet is 10. 0g / m2 or more and 16. 5g / m2 or more, an outermost layer sheet is a first embossed sheet having first embossments, and an innermost layer sheet is a second embossed sheet having second embossments different from the first embossments, in the toilet roll, the densities of the embossed depressions of the first embossments are 15.0 / cm2 or more and 35.0 / cm2 or less, the densities of the embossed depressions of the second embossments are 40.0 / cm2 or more and 80.0 / cm2 or less, and the geometric mean √ (Tm * Tc) calculated as the square root of the product of the dry tensile strength Tm in the longitudinal direction and the dry tensile strength Tc in the widthwise direction of the toilet paper is 2. 40N or more and 4. 50N or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a toilet roll in which toilet paper is wound into a roll, and a method for manufacturing the same. [Background technology]

[0002] In the field of toilet paper, there is a growing demand for high-end toilet rolls that are multi-ply, with three or more sheets stacked together.

[0003] Patent Document 1 aims to provide a 3-ply or 4-ply toilet roll having decorative embossing, which is excellent in aesthetics and smoothness and softness on both the front and back sides, and which is less likely to peel off, and describes a 3-ply or 4-ply toilet roll, in which one or two plies on the front side of the toilet roll have decorative embossing, and two or three plies on the back side of the toilet roll have micro-embossing, and one ply on the back side of the one or two plies with decorative embossing and one ply on the front side of the two or three plies with micro-embossing are bonded with adhesive, and TS750 on the back side of the toilet roll has a noise level of 12 dBV when the 3 or 4 plies are laminated. 2 rms over 40dBV 2 It discloses toilet rolls that are below rms. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-023561 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when trying to improve the feel of high-end toilet rolls, such as smoothness and softness, the toilet paper tends to tear more easily when pulled out from the toilet roll.

[0006] The present invention was made in view of the above circumstances, and aims to provide a toilet roll in which multi-ply toilet paper, made of three or more overlapping sheets, is wound into a roll, which has an excellent feel to the touch and is less likely to tear when the toilet paper is pulled out from the toilet roll, and a method for manufacturing the same. [Means for solving the problem]

[0007] As a result of intensive research to solve the above problems, the present inventors have discovered a toilet roll in which multi-ply toilet paper, in which three or more sheets are superimposed, is wound into a roll, and the basis weight of each of the three or more sheets is 10.0 g / m 2 More than 16.5g / m 2 or less, wherein the outermost sheet of the three or more sheets located on the outermost side of the toilet roll is a first embossed sheet having a first embossment, and the innermost sheet of the three or more sheets located on the innermost side of the toilet roll is a second embossed sheet having a second embossment different from the first embossment, and the density of the embossed recesses of the first embossment on the outermost sheet is 15.0 pcs / cm 2 More than 35.0 pieces / cm 2 and the density of the embossed recesses of the second embossing in the innermost layer sheet is 40.0 pcs / cm 2 More than 80.0 pieces / cm 2 It has been found that the above problem can be solved by a toilet roll having a geometric mean √(Tm×Tc), calculated as the square root of the product of the dry tensile strength Tm in the longitudinal direction of the toilet paper and the dry tensile strength Tc in the width direction of the toilet paper, of 2.40 N or more and 4.50 N or less.

[0008] The inventor also developed a toilet roll in which three or more sheets of multi-ply toilet paper are wound into a roll, and the basis weight of each of the three or more sheets is 10.0 g / m 2 More than 16.5g / m 2 or less, wherein the outermost sheet of the three or more sheets located on the outermost side of the toilet roll is a first embossed sheet having a first embossment, and the innermost sheet of the three or more sheets located on the innermost side of the toilet roll is a second embossed sheet having a second embossment different from the first embossment, and the density of the embossed recesses of the first embossment on the outermost sheet is 15.0 pcs / cm 2 More than 35.0 pieces / cm 2 The density of the embossed recesses of the second embossing in the innermost layer sheet is 40.0 pcs / cm 2 More than 80.0 pieces / cm 2 The inventors have found that the above problem can be solved by providing a toilet roll having a dry tensile strength Tm in the longitudinal direction of the toilet paper of 3.50 N or more and 5.00 N or less.

[0009] Specifically, the present invention has the following configuration.

[0010] [1] A toilet roll in which multi-ply toilet paper, in which three or more sheets are stacked, is wound into a roll, The basis weight per sheet of 3 or more sheets is 10.0 g / m 2 More than 16.5g / m 2 is as follows: an outermost sheet of the three or more sheets positioned at the outermost side of the toilet roll is a first embossed sheet having a first embossment; the innermost sheet of the three or more sheets located at the innermost side of the toilet roll is a second embossed sheet having a second embossment different from the first embossment; The density of the embossed depressions of the first embossment on the outermost layer sheet is 15.0 pcs / cm 2 More than 35.0 pieces / cm 2and the density of the embossed recesses of the second embossing in the innermost layer sheet is 40.0 pcs / cm 2 More than 80.0 pieces / cm 2 is as follows: A toilet roll characterized in that the geometric mean √(Tm × Tc), calculated as the square root of the product of the dry tensile strength Tm in the longitudinal direction of the toilet paper and the dry tensile strength Tc in the width direction of the toilet paper, is 2.40 N or more and 4.50 N or less. [2] The toilet roll according to [1], characterized in that the dry tensile strength Tm of the toilet paper in the longitudinal direction is 3.50 N or more and 5.00 N or less. [3] A toilet roll in which multi-ply toilet paper, in which three or more sheets are stacked, is wound into a roll, The basis weight per sheet of 3 or more sheets is 10.0 g / m 2 More than 16.5g / m 2 is as follows: an outermost sheet of the three or more sheets positioned at the outermost side of the toilet roll is a first embossed sheet having a first embossment; the innermost sheet of the three or more sheets located at the innermost side of the toilet roll is a second embossed sheet having a second embossment different from the first embossment; The density of the embossed depressions of the first embossment on the outermost layer sheet is 15.0 pcs / cm 2 More than 35.0 pieces / cm 2 The density of the embossed recesses of the second embossing in the innermost layer sheet is 40.0 pcs / cm 2 More than 80.0 pieces / cm 2 is as follows: A toilet roll characterized in that the dry tensile strength Tm of the toilet paper in the longitudinal direction is 3.50 N or more and 5.00 N or less. [4] The toilet roll according to any one of [1] to [3], characterized in that the ratio Tc / Tm of the dry tensile strength Tc in the width direction of the toilet paper to the dry tensile strength Tm in the length direction of the toilet paper is 50.0% or more. [5] The toilet roll according to any one of [1] to [4], characterized in that, at the position where the toilet paper is unwound from the outer end of the roll to 50% of the winding length, the depth of the embossed recesses of the first embossing is 70 μm or more and 120 μm or less, and the depth of the embossed recesses of the second embossing is 60 μm or more and 100 μm or less. [6] The toilet roll according to any one of [1] to [5], characterized in that the second embossing has a dot shape uniformly arranged over the entire surface of the second embossed sheet, and the diameter of the embossed depression of the second embossing is 0.50 mm or more and 0.95 mm or less at the position where the toilet paper is unwound from the outer end of the roll to 50% of the winding length. [7] Using the tissue softness analyzer TSA, a toilet paper sample is placed on the sample stage with the inside of the roll facing up. A bladed rotor is pressed from above with a pressure of 100mN, and then rotated at a speed of 2.0 rpm. The vibration of the sample stage is measured with a vibration sensor. The TS7 value, which is the intensity of the maximum peak in the spectrum containing a frequency of 6500Hz, is 12.0dBV. 2 rms above 25.0dBV 2 The toilet roll according to any one of [1] to [6], characterized in that it is rms or less. [8] A method for manufacturing a toilet roll in which multi-ply toilet paper is wound into a roll, the multi-ply toilet paper being made up of three or more sheets stacked together, including a first embossed sheet having a first embossment and a second embossed sheet having a second embossment different from the first embossment, The density of the embossed recesses in the first embossing is 15.0 pieces / cm 2 More than 35.0 pieces / cm 2 preparing a first embossed sheet, The density of the embossed recesses in the second embossing is 40.0 pieces / cm 2 More than 80.0 pieces / cm 2 preparing a second embossed sheet, which is overlapping three or more sheets so that a first embossed sheet and a second embossed sheet are disposed on opposite sides of the toilet paper; A step of winding the three or more overlapping sheets into a toilet paper roll so that the first embossed sheet is located on the outermost side of the toilet roll and the second embossed sheet is located on the innermost side of the toilet roll; A method comprising: [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a toilet roll in which multi-ply toilet paper, in which three or more sheets are overlapped, is wound into a roll, which has an excellent feel to the touch and is less likely to tear when the toilet paper is pulled out from the toilet roll, and a method for manufacturing the same. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram illustrating the configuration of a toilet roll according to an embodiment of the present invention. FIG. [Figure 2] 1A to 1C are diagrams illustrating an example of the configuration of toilet paper according to an embodiment of the present invention. [Figure 3] FIG. 10 is a diagram illustrating a method for measuring the size and depth of an embossed depression. [Figure 4] FIG. 1 is a diagram showing an example of manufacturing equipment applicable to the manufacture of toilet rolls according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] In the field of toilet paper, a pleasant feel, such as softness and smoothness, is one of the important required qualities. However, when trying to improve the feel of toilet paper, the strength of the toilet paper generally weakens, and the toilet paper tends to tear easily when pulled out from the toilet roll.

[0014] The present invention aims to solve the above problems.

[0015] Hereinafter, a toilet roll and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to the drawings. The following embodiments and drawings are provided for illustrative purposes and are not intended to limit the present invention.

[0016] (First embodiment of the present invention) The toilet roll 100 according to the first embodiment of the present invention has a configuration in which, in the multi-ply toilet paper 10 of three or more plies that constitutes the toilet roll 100, the outermost sheet 10a is a first embossed sheet with a first embossment, and the innermost sheet 10b is a second embossed sheet with a second embossment that is different from the first embossment. Furthermore, the basis weight per sheet of the three or more sheets that constitute the toilet paper 10 is 10.0 g / m. 2 More than 16.5g / m 2 Furthermore, the geometric mean √(Tm×Tc), calculated as the square root of the product of the dry tensile strength Tm in the longitudinal direction of the toilet paper 10 and the dry tensile strength Tc in the width direction of the toilet paper, is 2.40 N or more and 4.50 N or less. (Second embodiment of the present invention) The toilet roll 100 according to the second embodiment of the present invention has a configuration in which, in the multi-ply toilet paper 10 of three or more plies that constitutes the toilet roll 100, the outermost sheet 10a is a first embossed sheet with a first embossing, and the innermost sheet 10b is a second embossed sheet with a second embossing that is different from the first embossing. Furthermore, the basis weight per sheet of the three or more sheets that constitute the toilet paper 10 is 10.0 g / m. 2 More than 16.5g / m 2 Furthermore, the dry tensile strength Tm of the toilet paper 10 in the longitudinal direction is 3.50 N or more and 5.00 N or less.

[0017] According to the embodiment of the present invention having the above configuration, (1) By using three or more sheets, it has a luxurious feel, and by having different embossings on both sides, the toilet paper can be both strong and soft. (2) By satisfying the combination of the basis weight, embossing conditions, and tensile strength conditions of the toilet paper, the toilet paper is less likely to tear when pulled out from the toilet roll while ensuring a good feel of the toilet paper. Such effects can be achieved.

[0018] (Toilet roll) Figure 1 is a schematic diagram illustrating the configuration of a toilet roll 100 according to an embodiment of the present invention. Figure 1(a) is a perspective view of the toilet roll 100, and Figure 1(b) is a partially enlarged view of toilet paper 10 pulled out from the toilet roll 100.

[0019] Referring to Figure 1, the toilet roll 100 according to this embodiment is formed by winding a predetermined length of toilet paper 10 around a cylindrical paper core 14. In this embodiment, the toilet paper 10 is a multi-ply toilet paper in which three or more toilet paper webs (hereinafter simply referred to as sheets) are layered on top of each other.

[0020] (Toilet roll width) The width W of the toilet roll 100 refers to the length of the toilet roll in the cross direction (CD) of the toilet paper 10 wound into the toilet roll 100. The width W of the toilet roll 100 is generally equal to the width and length of the toilet paper 10 wound into the toilet roll 100, due to the manufacturing process including a step of cutting a wide winding roll (log) to obtain toilet rolls of the product width. In an embodiment of the present invention, the width W of the toilet roll 100 is set to a length that allows it to fit into a typical toilet roll holder and be supported rotatably therein. The width W of the toilet roll 100, i.e., the width of the toilet paper 10, is set to 114 mm as specified in the JIS standard as a reference value, and may be, for example, 90 mm or more and 120 mm or less, and is often around 95 mm to 110 mm. The width W of the toilet roll 100 can be measured using, for example, a vernier caliper or a tape measure.

[0021] (Toilet roll length) In an embodiment of the present invention, the roll length L of the toilet roll 100, which is the length (total length) of the toilet paper 10 wound around the paper tube 14, is preferably 20 m or more and 50 m or less. If the roll length L of the toilet roll is within this range, the roll diameter DR of the toilet roll will not be so large that it will not fit into a typical toilet roll holder, while the length will be appropriate, reducing the frequency of changing the toilet roll during use. The roll length L can be determined, for example, by actually measuring the length of the toilet paper 10 while unwinding it from the toilet roll 100.

[0022] (Paper tube) The cardboard tube 14 is a component that serves as the core of the toilet roll 100. The cardboard tube 14 is formed from thick paper such as cardboard with a thickness of 0.5 mm to 1.5 mm. The core diameter DC, which is the outer diameter of the cardboard tube 14, is, for example, 30 mm to 50 mm, and preferably 35 mm to 45 mm.

[0023] (mass of toilet roll) In an embodiment of the present invention, the mass of the toilet roll 100, including the cardboard tube 14, is 100 g or more and 400 g or less, preferably 110 g or more and 200 g or less, and more preferably 125 g or more and 180 g or less. Toilet rolls are generally sold in packages containing 2 to 24 rolls, and if the mass of one roll of toilet roll is within this range, it can be packaged in an appropriate number to suit the commercial form. If the cardboard tube 14 is made of thick paper such as cardboard, the mass of the cardboard tube 14 is generally 10 g or less, and preferably 5 g or less.

[0024] (Toilet roll diameter) In an embodiment of the present invention, the roll diameter DR of the toilet roll 100, which is the roll diameter of the rolled toilet paper 10, is preferably 100 mm or more and 134 mm or less. If the toilet roll roll diameter DR is within this range, the toilet roll will fit into a typical toilet roll holder and can be supported rotatably therein, and will have a certain degree of roll length, reducing the frequency with which the toilet roll needs to be replaced.

[0025] The reel diameter DR can be determined, for example, by the following method. First, the circumference of the toilet roll 100 is measured using a tape measure at three positions: both ends and the center in the axial direction of the toilet roll 100. Next, each circumference measurement is divided by pi, 3.14, to calculate the reel diameter at each of the three positions, and the average of the reel diameters at the three positions is calculated. The calculated average is used as the reel diameter DR of the toilet roll 100.

[0026] (Toilet roll density) In an embodiment of the present invention, the winding density of the toilet roll 100 is 0.90 m / cm 2 More than 2.30m / cm 2 In particular, when the toilet paper 10 is 3-ply, the winding density is preferably 0.90 m / cm or less. 2 More than 1.70m / cm 2In addition, when the toilet paper 10 is 4-ply, it is preferable that the thickness is 1.00 m / cm or less. 2 More than 1.90m / cm 2 Preferably, it is 1.05 m / cm or less. 2 More than 1.50m / cm 2 More preferably, it is:

[0027] Toilet roll density [unit: m / cm 2 ] is calculated by the following formula (I): (Roll density) = (Roll length x number of plies) ÷ (cross-sectional area of ​​toilet roll) (I)

[0028] The cross-sectional area of ​​the toilet roll 100 corresponds to the area of ​​the portion of the end face of the toilet roll 100 that is made up of toilet paper 10. In other words, the cross-sectional area of ​​the toilet roll 100 is the area of ​​a circle whose diameter is the reel diameter DR minus the area of ​​a circle whose diameter is the core diameter DC, which is the outer diameter of the cardboard tube 14. The cross-sectional area of ​​the toilet roll is calculated by the following formula (II): (Cross-sectional area) = (Toilet roll diameter DR ÷ 2) 2 ×3.14-(core diameter DC÷2) 2 ×3.14···(II)

[0029] Specifically, in one example, if the toilet paper 10 is 4 ply, the toilet roll 100 has a roll length of 25 m, a roll diameter of 113 mm, and the core diameter of the paper tube 14 is 40 mm, the winding density is (25 m × 3) ÷ {(113 mm ÷ 2)} 2 ×3.14-(40mm÷2) 2 × 3.14} to get 1.14 m / cm 2 This becomes:

[0030] When the winding density of the toilet roll is within the above range, it is possible to obtain a toilet roll that is pleasant to the touch and maintains the softness of toilet paper while satisfying the above-mentioned preferred winding diameter and winding length.

[0031] (Toilet roll density) In an embodiment of the present invention, the density of the toilet roll 100 is 0.100 g / cm 3 More than 0.300g / cm 3 or less, preferably 0.100 g / cm 3 More than 0.200g / cm 3 or less, more preferably 0.100 g / cm 3 More than 0.180g / cm 3 The following is the following:

[0032] Density of toilet paper (unit: g / cm 3 ) is calculated by the following formula (III): (Density) = (Mass of toilet roll (excluding the mass of the paper tube)) ÷ Volume of toilet roll (III)

[0033] Here, the volume of the toilet roll 100 can be calculated by multiplying the area of ​​the portion of the end face of the toilet roll 100 that is made up of toilet paper 10 (the cross-sectional area of ​​the toilet roll expressed by the above formula (II)) by the width W of the toilet roll. In other words, the volume of the toilet roll is calculated by the following formula (IV): (Volume of toilet roll) = (Cross-sectional area of ​​toilet roll) × (Width of toilet roll W) (IV)

[0034] Here, by substituting formula (IV) into formula (III), (Density) = (Mass of toilet roll (excluding the mass of the paper core)) ÷ {(Cross-sectional area of ​​toilet roll) × (Width of toilet roll W)} (V) This becomes:

[0035] Specifically, for example, if the roll diameter of the toilet roll 100 is 113 mm, the core diameter of the paper tube 14 is 40 mm, the width W of the toilet roll is 109 mm, and the mass of the toilet roll (excluding the mass of the paper tube) is 131.6 g, the density is (131.6 g) ÷ [{(11.3 cm ÷ 2) 2 ×3.14-(4cm÷2) 2× 3.14) × 10.9 cm, and calculate the value to be 0.138 g / cm 3 This becomes:

[0036] When the density of the toilet roll is within the above range, the toilet paper can be obtained with a soft, fluffy feel that is pleasant to the touch.

[0037] (toilet paper) Referring to Figure 1(b), in this embodiment, the toilet paper 10 is a three-ply toilet paper made up of three overlapping sheets. However, the present invention is not limited to this, and the toilet paper 10 can also be a multi-ply toilet paper made up of four or more overlapping sheets, that is, four or more ply toilet paper.

[0038] The three-ply toilet paper 10 shown in FIG. 1(b) is a laminated sheet in which three sheets 10a, 10c, and 10b are stacked in this order. Of these three sheets, sheet 10a is the outermost sheet located on the outermost side of the toilet roll 100. In the present invention, the outermost sheet 10a is a first embossed sheet having a first embossment 15. Sheet 10b is the innermost sheet located on the innermost side of the toilet roll 100. In the present invention, the innermost sheet 10b is a second embossed sheet having a second embossment 12 that is different from the first embossment. Sheet 10c is an intermediate sheet located between the outermost sheet 10a and the innermost sheet 10b. In the example shown in FIG. 1(b), the intermediate sheet 10c is an embossed sheet having an embossment. In this example, the embossing pattern is substantially the same as the second embossments 12 formed integrally with the second embossments 12 of the innermost layer sheet 10b. However, in the embodiments of the present invention, the intermediate layer sheet 10c may be an embossed sheet or a non-embossed sheet. Furthermore, when the intermediate layer sheet 10c is an embossed sheet, there are no limitations on the embossing pattern, and it may be substantially the same as the first embossments 15 formed integrally with the first embossments 15 of the outermost layer sheet 10a, or may be substantially the same as the second embossments 12 formed integrally with the second embossments 12 of the innermost layer sheet 10b, or may be any other embossing pattern.

[0039] FIG. 2 is a schematic diagram showing an example of a layer structure of toilet paper 10 applicable to the toilet roll 100 according to an embodiment of the present invention.

[0040] As mentioned above, the present invention is applicable to any multi-ply toilet paper of 3 or more plies, but is particularly applicable to 3-ply and 4-ply toilet paper. Therefore, Figure 2 shows an example of a 3-ply toilet paper with 3 sheets stacked on top of each other and an example of a 4-ply toilet paper with 4 sheets stacked on top of each other as non-limiting configuration examples of multi-ply toilet paper 10 to which the present invention can be applied.

[0041] Fig. 2(a) shows an example of a three-ply structure, and Fig. 2(b) shows an example of a four-ply structure.

[0042] 2(a) and 2(b), the outermost layer sheet 10a constituting the outer surface 10A, of the two outer surfaces 10A, 10B of the toilet paper 10, located on the outer side of the toilet roll 100, is a first embossed sheet having a first embossing 15. Also, the innermost layer sheet 10b constituting the outer surface 10B, of the two outer surfaces 10A, 10B of the toilet paper 10, located on the inner side of the toilet roll 100, is a second embossed sheet having a second embossing 12 that is different from the first embossing.

[0043] In the three-ply configuration example shown in Figure 2(a), the intermediate layer sheet 10c located between the outermost layer sheet 10a and the innermost layer sheet 10b may be an embossed sheet or a non-embossed sheet. Figures 2(a-1) and 2(a-2) are non-limiting preferred specific examples of the configuration of Figure 2(a), showing an example in which the intermediate layer sheet 10c is an embossed sheet. In the example of Figure 2(a-1), the intermediate layer sheet 10c has an embossing pattern that is substantially identical to the embossing pattern 12 formed integrally with the embossing pattern 12 of the innermost layer sheet 10b. In the example of Figure 2(a-2), the intermediate layer sheet 10c has an embossing pattern that is substantially identical to the embossing pattern 15 formed integrally with the embossing pattern 15 of the outermost layer sheet 10a.

[0044] Here, the configuration shown in (a-1) of FIG. 2 corresponds to the configuration shown in (b) of FIG.

[0045] In the four-ply configuration example shown in Figure 2(b), the toilet paper 10 has two intermediate sheets 10c located between the outermost sheet 10a and the innermost sheet 10b. The two intermediate sheets 10c are shown in the figure as intermediate sheet 10c1 and intermediate sheet 10c2, in order from the side closest to the outermost sheet 10a. Each of the intermediate sheets 10c (i.e., intermediate sheets 10c1 and 10c2) may be a non-embossed sheet or an embossed sheet.

[0046] (b-1) to (b-3) in FIG. 2 are non-limiting preferred specific examples of the configuration in (b) in FIG. 2, in which the intermediate layer sheets 10c1 and 10c2 are both embossed sheets.

[0047] In the example of Figure 2 (b-1), of the two intermediate layer sheets 10c, intermediate layer sheet 10c1 has an embossing pattern that is substantially the same as the embossing 15 formed integrally with the embossing 15 on the outermost layer sheet 10a. Furthermore, intermediate layer sheet 10c2 has an embossing pattern that is substantially the same as the embossing 12 formed integrally with the embossing 12 on the innermost layer sheet 10b. In other words, the toilet paper 10 has a configuration in which a two-ply embossed sheet consisting of sheets 10a and 10c1 and a two-ply embossed sheet consisting of sheets 10b and 10c2 are laminated together.

[0048] In the example of Fig. 2(b-2), the two middle layer sheets 10c1 and 10c2 both have approximately the same embossing pattern as the embossing 12 formed integrally with the embossing 12 of the innermost layer sheet 10b. In other words, the toilet paper 10 has a laminated configuration of a single-ply embossed sheet consisting of sheet 10a alone and a three-ply embossed sheet consisting of sheets 10b, 10c2, and 10c1.

[0049] In the example of Figure 2 (b-3), the two middle layer sheets 10c1 and 10c2 both have embossing patterns that are substantially the same as the embossing 15 formed integrally with the embossing 15 on the outermost layer sheet 10a. In other words, the toilet paper 10 has a configuration in which a single-ply embossed sheet consisting of sheet 10b alone and a three-ply embossed sheet consisting of sheets 10a, 10c1, and 10c2 are laminated together.

[0050] As shown in Figure 2, toilet paper with different embossings on both sides can provide a decorative appearance and also provide a pleasant feel, such as softness and smoothness. Also, as shown in (a-1), (a-2), (b-1), (b-2), and (b-3) of Figure 2, a configuration in which all sheets that make up the toilet paper are embossed can reduce the paper thickness of the toilet paper compared to a configuration in which non-embossed sheets are included, and therefore the roll diameter can be reduced and the roll length of the toilet paper can be increased.

[0051] (sheet) Each of the sheets 10a, 10c, and 10b that make up the toilet paper 10 is obtained by papermaking a slurry containing a pulp component, which is a fiber raw material.

[0052] (pulp component) Pulp components include wood pulp, non-wood pulp, and recycled paper pulp. Examples of wood pulp produced using wood as a raw material include chemical pulps such as hardwood pulp (hardwood kraft pulp (LKP)), softwood pulp (softwood kraft pulp (NKP)), sulfite pulp (SP), dissolving pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP), and oxygen-bleached kraft pulp (OKP). Other examples include semi-chemical pulps such as semi-chemical pulp (SCP) and chemi-groundwood pulp (CGP), and mechanical pulps such as groundwood pulp (GP), and thermomechanical pulp (TMP, BCTMP), but are not limited thereto. Non-wood pulps produced from plants or animals other than wood include, but are not limited to, cotton pulps such as cotton linters and cotton lint, non-wood pulps such as hemp, wheat straw, and bagasse, and cellulose, chitin, and chitosan isolated from sea squirts and seaweed. Examples of waste paper pulp produced using waste paper (pulp produced from papermaking) as a raw material include, but are not limited to, so-called milk carton pulp, which is made from paper cartons used to fill and package liquids, such as milk cartons, and deinked pulp, which is made from newspapers, magazines, etc.

[0053] The pulp component may be one of the above types, or a mixture of two or more types. These pulp components have a significant effect on the quality of the toilet paper, so they are appropriately blended in the specified types and proportions according to the required quality.

[0054] For example, at least one selected from softwood pulp and hardwood pulp can be preferably used as the pulp component. Softwood pulp has long, strong fibers and can impart strength to the sheet produced. Hardwood pulp has short, flexible fibers and can provide uniformity, good texture, softness, and the like to the sheet produced. In an embodiment of the present invention, it is preferable to use a combination of softwood pulp and hardwood pulp, and it is more preferable to use a combination of softwood kraft pulp (NKP) and hardwood kraft pulp (LKP).

[0055] When softwood pulp and hardwood pulp are used in combination, the L / N ratio, which indicates the blending ratio (mass ratio) of softwood pulp to hardwood pulp, is preferably, for example, 10 / 90 to 90 / 10, more preferably 20 / 80 or more, even more preferably 30 / 70 or more, and more preferably 80 / 20 or less, even more preferably 70 / 30 or less.

[0056] (optional ingredient) Various chemicals may be added as optional components to the sheet to achieve the required quality and stabilize operations. Examples of optional components include dry strength agents, wet strength agents, softeners, bulking agents, dyes, fragrances, dispersants, drainage aids, pitch control agents, retention aids, and sizing agents. Examples of dry strength agents include cationized starch, polyacrylamide (PAM), and carboxymethyl cellulose (CMC). Examples of wet strength agents include polyamide epichlorohydrin, urea, melamine, and thermally crosslinkable polyacrylamide. Examples of softeners include anionic surfactants, nonionic surfactants, cationic surfactants, and zwitterionic surfactants. The above optional components may be used alone or in combination.

[0057] In the embodiment of the present invention, the types (paper quality such as material and physical properties) of the sheets 10a, 10c, and 10b to be stacked on top of each other may be the same or different depending on the required quality and the like.

[0058] (basis weight per sheet) In an embodiment of the present invention, the basis weight of each of the multiple sheets constituting the multi-ply toilet paper 10 is 10 g / m 2 More than 16.5g / m 2 The basis weight per sheet is 10 g / m 2 It is sufficient if it is 10.5g / m or more. 2 It is preferable that the content is 11 g / m or more. 2 More preferably, it is 11.4 g / m or more. 2 It is more preferable that the basis weight per sheet is 16.5 g / m or more. 2 It is sufficient if it is less than 15g / m 2 Preferably, it is 14 g / m or less. 2 More preferably, it is 13 g / m or less. 2 It is even more preferable that:

[0059] The basis weight per sheet can be determined in accordance with the provisions of Japanese Industrial Standard JIS P8124 by measuring the basis weight of the multi-ply toilet paper 10 and dividing the basis weight by the number of plies.

[0060] Specifically, for example, in an embodiment with three plies as shown in (a) and (b) of FIG. 2, the three-ply toilet paper 10 is conditioned according to the method specified in the Japanese Industrial Standard JIS P8111, and the three constituent sheets 10a, 10c, and 10b are stacked on top of each other, and the three-ply toilet paper 10 is cut into a predetermined size, for example, 10 cm x 10 cm, and the weight of the cut-out three-ply toilet paper 10 is measured, and the weight is multiplied by 0.01 m of the cut-out area of ​​the three-ply toilet paper 10. 2 The basis weight per sheet can be calculated by dividing the basis weight by the number of plies, which is 3. In embodiments where the number of plies is 4 or more, the basis weight per sheet can be calculated by dividing the basis weight of the toilet paper 10 by the number of plies.

[0061] In this way, the basis weight per sheet of the multiple sheets that make up the multi-ply toilet paper 10 is calculated as an average value, but it is preferable that the actual basis weight per sheet is all within the above range.

[0062] By setting the basis weight per sheet within the above range, it becomes easier to produce a toilet roll with the desired roll diameter. That is, in the toilet roll production process, normally, when toilet paper is wound into a roll, tension is applied to control the roll diameter, but by setting the basis weight per sheet within the above range, the sheet has a certain degree of strength and is less likely to tear, and a toilet roll with the desired roll diameter can be produced using appropriate tension.

[0063] (Embossed) Referring to Figures 1 and 2, in an embodiment of the present invention, of the two outer surfaces 10A and 10B of toilet paper 10, outer surface 10A has a first embossing 15, and outer surface 10B has a second embossing 12 that is different from the first embossing.

[0064] (First embossing) The first embossments 15 are provided as a number of embossments 15 arranged in a repeating pattern across the entire surface (whole surface) of one outer surface 10A of the toilet paper 10, primarily to impart design features to the toilet paper 10. This physical treatment of the fibers constituting the sheet can impart unevenness, bulkiness, and a fluffy softness to the sheet 10a constituting the outer surface 10A.

[0065] (Second embossing) The second embossments 12 are provided as a number of embossments 12 arranged uniformly across the entire surface (whole surface) of one outer surface 10B of the toilet paper 10, with the main purpose of modifying the physical properties of the sheet. This physically processes the fibers that make up the sheet, softening the sheet 10b that makes up the outer surface 10B.

[0066] In an embodiment of the present invention, the shape of each of the numerous embossments 12 is preferably circular when the outer surface 10B is viewed from above. In this specification, the term "circular" includes not only a perfect circle but also an approximately perfect circle, an ellipse, a polygonal shape with rounded corners, and the like. The shapes and sizes of the individual embossments 12 may be the same or different. From the perspective of the comfortable feel of the toilet paper 10, it is preferable that the shape of the embossments has as few corners as possible. The dimensions and arrangement of the numerous embossments 12 on the embossed sheet may also be determined taking into consideration the design.

[0067] Thus, in the embodiment of the present invention, by having different embossings on both the outer surface 10A and the outer surface 10B, the fabric can be soft and smooth, providing a pleasant feel against the skin.

[0068] In addition, in an embodiment of the present invention, the toilet paper 10 may optionally be provided with an embossed portion 13 for bonding that is arranged in a partial area rather than the entire paper surface in order to prevent ply peeling.

[0069] In an embodiment of the present invention, the numerous embossments 15 arranged on the outer surface 10A of the toilet paper 10 may be embossed recesses where the embossed portions are recessed from the surface, or may be embossed protrusions where the embossed portions protrude from the surface. Also, the numerous embossments 12 arranged on the outer surface 10B of the toilet paper 10 may be embossed recesses where the embossed portions are recessed from the surface, or may be embossed protrusions where the embossed portions protrude from the surface.

[0070] If the numerous embossments 15 arranged on the outer surface 10A of the toilet paper 10 are embossed recesses that do not protrude from the surface, the surface of the toilet paper 10 will be smoother, which is preferable, compared to when the embossments are embossed protrusions that protrude from the surface. Similarly, if the numerous embossments 12 arranged on the outer surface 10B of the toilet paper 10 are embossed recesses that do not protrude from the surface, the surface of the toilet paper 10 will be smoother, which is preferable, compared to when the embossments are embossed protrusions that protrude from the surface. In the following, for ease of explanation, the outer surface 10A and the outer surface 10B will be described as having embossed recesses 15 and embossed recesses 12, respectively, but this is not intended to limit the invention. Furthermore, since the embossed recesses 15 and embossed recesses 12 can be formed using the same method, the following description will focus on the method of forming the embossed recesses 12.

[0071] The embossed recesses 12 can be formed by embossing at least the sheet 10b that constitutes the outer surface 10B.

[0072] (embossed) Embossing refers to a process in which embossed recesses are formed on one of the two surfaces of a sheet (which may be a single sheet or a laminated sheet) to be embossed, and embossed protrusions, consisting of the reverse side of the embossed recesses, are formed on the other surface. Embossing can be performed by known methods. For example, embossing may be performed using "matched" embossing rolls, in which a male (convex) embossing roll and a female (concave) embossing roll of approximately complementary shapes engage with each other; or it may be performed using so-called "mismatched" embossing rolls, in which the male (convex) embossing roll and the female (concave) embossing roll are not identical in shape and apply a shear force to the sheet when they engage with each other; or it may be performed using a male (convex) embossing steel roll and a plain rubber roll.

[0073] When forming embossed depressions 12 on the outer surface 10B of the toilet paper 10, the embossing is performed by bringing a male (convex) embossing roll into contact with the surface of the sheet 10b that will become the outer surface 10B of the toilet paper 10.

[0074] In the three-ply embodiment shown in Figures 1(b) and 2(a-2), not only is sheet 10b embossed, but also the underlying sheet 10c, while sheet 10a is embossed separately. This three-ply construction can be achieved by performing one embossing process (second embossing) on ​​sheets 10b and 10c, another embossing process (first embossing) on ​​sheet 10a, and then stacking these three sheets 10b, 10c, and 10a together.

[0075] The following describes the embossing of sheets 10b and 10c, focusing on two plies, sheets 10b and 10c, of the three-ply structure of toilet paper 10. Generally, embossing of two-ply sheets is classified into so-called double embossing, in which each of the two sheets making up the two plies is embossed and then they are stacked together, and so-called single embossing, in which the two sheets are stacked together and then the entire stack is embossed.

[0076] In the embodiment of the present invention, the embossing on the sheets 10b and 10c may be double embossing or single embossing.

[0077] Here, single embossing, in which two sheets are stacked and then embossed, can keep the overall paper thickness of the toilet paper relatively low compared to double embossing, in which two sheets are stacked after being embossed to increase the paper thickness. Therefore, single embossing can achieve the following effects compared to double embossing. (1) The roll length can be increased for the same roll diameter. Therefore, it can better accommodate the trend toward longer rolls of toilet paper. (2) Generally, when embossing, increasing the embossing depth increases the bulk and, as a result, the thickness of the paper increases. With single embossing, the increase in paper thickness due to embossing is smaller than with double embossing, so the embossing depth can be made greater. This can improve the softness of the sheet.

[0078] Furthermore, double embossing results in relatively larger gaps between the constituent sheets compared to single embossing, which can improve the water retention of the toilet paper.

[0079] (embossing depth)

[0080] 3(a), in this specification, when toilet paper 10 with a winding length L is unwound from the toilet roll 100, the outer end of the toilet paper 10 in the longitudinal direction (MD) of the toilet paper 10 will be referred to as the 0% position, and the inner end of the roll will be referred to as the 100% position. Also, the intermediate position, which is half the winding length L of the toilet paper 10 as viewed from the outer end of the roll, i.e., the length L / 2, will be referred to as the 50% position. Similarly, the position at 10% of the winding length L of the toilet paper 10 as viewed from the outer end of the roll will be referred to as the 10% position, and the position at 90% of the winding length L of the toilet paper 10 as viewed from the outer end of the roll will be referred to as the 90% position.

[0081] In an embodiment of the present invention, the embossment depth D, which is the depth of the embossed depressions 12 in the innermost sheet of the toilet paper 10 measured at the 50% position, in other words, the position where the toilet paper 10 has been unwound from the outer edge of the roll to 50% of the winding length (i.e., the depth of the embossed depressions of the second embossment), is preferably 60 μm or more and 100 μm or less, and more preferably 63 μm or more and 95 μm or less. Hereinafter, in this specification, the embossment depth D measured at the 50% position will also be referred to as embossment depth D(50%).

[0082] In an embodiment of the present invention, the embossing depth D (50%), which is the depth of the embossed depressions 15 in the outermost layer sheet of the toilet paper 10, is preferably 70 μm or more and 120 μm or less, and more preferably 75 μm or more and 110 μm or less.

[0083] The embossing depth can be controlled by a combination of adjustments, such as the pulp composition of the sheet that makes up the toilet paper (type of pulp components, blending ratio, etc.), the setting of the embossing depth D in the toilet roll manufacturing process (adjusting the tooth profile of the embossing roll used for embossing, the embossing roll pressure applied during embossing, etc.), and adjusting the tension applied to the sheet.

[0084] (Method for measuring embossing depth) The measurement method for embossing depth D is explained below. Embossing depth D can be determined by measuring the height difference of the embossment using a shape-measuring laser microscope. The shape-measuring laser microscope scans the XY plane within the observation field, dividing it into multiple pixels, with a laser light source, via an objective lens, and detects the reflected light from each pixel with a light-receiving element. The objective lens is then driven in the height (Z-axis) direction, and height information and the amount of reflected light are detected, with the Z-axis position with the highest amount of reflected light as the focal point. By repeating this scan, a fully focused ultra-deep-depth image and height image (information) can be obtained. The laser light source is a pinhole confocal optical system, ensuring high measurement accuracy.

[0085] As a shape measurement laser microscope, for example, a product name "One-Shot 3D Measuring Macroscope VR-3200" manufactured by KEYENCE Corporation can be used. As software for observing, measuring, and analyzing images from the laser microscope, for example, a product name "VR-H2A" can be used. In this embodiment, measurements are performed under conditions of a measurement magnification of 12x and a field of view area of ​​24mm x 18mm. Note that the measurement magnification and field of view area may be changed as appropriate depending on the desired size of the embossment.

[0086] As shown schematically in Figure 3(b), the measurement of the depth D of the embossed depressions 12 is performed on the inner surface 10B of the roll of toilet paper 10 on which the embossed depressions are provided. Additionally, the measurement of the depth D of the embossed depressions 15 is performed on the outer surface 10A of the roll of toilet paper 10 on which the embossed depressions are provided. Since the measurement method for both is the same, the measurement method for measuring the depth of the embossed depressions 12 will be described below.

[0087] Referring to FIG. 3(c), first, the longest part a where the linear distance between two opposing points on the periphery Erim of the embossed recess 12 is longest is found.

[0088] Using the shape measurement laser microscope, a two-point measurement is performed to obtain a cross-sectional curve profile. Next, select "Waviness curve" from the "Line roughness measurement settings" and set the cutoff λc to 800 μm, and then obtain the waviness curve U shown in Figure 3(d).

[0089] Referring to Figure 3(d), two inflection points P1 and P2 that are convex upward on this undulation curve U are found, and then the minimum value between the inflection points P1 and P2 is found and this minimum value is taken as the minimum depth value Min. Furthermore, the average value of the depth values ​​at the inflection points P1 and P2 is taken as the maximum depth value Max. In this way, the embossing depth D is found using the following formula (VI). Embossing depth D = Maximum value Max - Minimum value Min (VI) The distance (length) on the XY plane between the inflection points P1 and P2 is defined as the length of the longest part a.

[0090] Similarly, referring to (c) of Figure 3, the embossing depth D is also measured for the longest part b, where the linear distance between two opposing points on the periphery Erim of the embossed depression 12 in the direction perpendicular to the longest part a is the longest. The larger of the embossing depths D of the longest part a and the longest part b is used as the embossing depth D of that one embossed depression 12. The above measurements are performed on any 10 embossed depressions 12 on the surface of the sheet 10b of the toilet paper 10, and the average value is used as the final embossing depth D.

[0091] When measuring the embossing depth D, it is measured at a portion corresponding to a predetermined position, such as the 50% position mentioned above. This is because the embossing depth D varies depending on the degree of crushing of the embossing between the start (100% position) and end (0% position) of the toilet paper 10 on the toilet roll 100. This reduces the influence of the measurement position as a factor in fluctuations in the measurement value.

[0092] (Diameter of embossed recess) In an embodiment of the present invention, when the outer surface 10B of the embossed toilet paper 10 is viewed from above, the embossed depressions 12 (second embossments) are preferably circular. The diameter of the embossed depressions 12 (hereinafter simply referred to as the embossment diameter) is preferably 0.50 mm or more and 0.95 mm or less, more preferably 0.55 mm or more and 0.90 mm or less, and even more preferably 0.60 mm or more and 0.85 mm or less. The diameter of the embossed depressions 15 (first embossments) (embossment diameter) is preferably 0.80 mm or more and 1.30 mm or less, more preferably 0.83 mm or more and 1.27 mm or less, and even more preferably 0.86 mm or more and 1.24 mm or less.

[0093] The longest part a obtained when measuring the embossment depth D is used as the embossment diameter. The longest part a is obtained for any 10 embosses that were used to measure the embossment depth D, and the average value is used as the final embossment diameter.

[0094] When measuring the embossment diameter, it is measured at the part corresponding to the 50% position mentioned above. This is because the embossment diameter varies depending on the degree of crushing of the embossment between the start (100% position) and end (0% position) of the toilet paper 10 on the toilet roll 100. This reduces the influence of the measurement position as a factor in fluctuations in the measurement value.

[0095] (embossing density) In the embodiment of the present invention, the density of the embossments 12 (second embossments) is 40.0 pieces / cm 2 More than 80.0 pieces / cm 2 or less, preferably 45 cells / cm 2 More than 75 pieces / cm 2 More preferably, 50 cells / cm or less. 2 More than 70 pieces / cm 2 The density of the embossments 15 (first embossments) is 15.0 pieces / cm 2 More than 35.0 pieces / cm 2 or less, preferably 16.5 cells / cm 2 More than 33.0 pieces / cm2 More preferably, 18.0 cells / cm or less. 2 More than 30.0 pieces / cm 2 The following is the result.

[0096] In this specification, the embossing density is the value obtained by counting the number of embossed depressions in a 10 cm x 10 cm area and converting it to a value per 1 cm x 1 cm, and is the average value of five depressions in a 10 cm x 10 cm area.

[0097] (Effects of embossing conditions) In an embodiment of the present invention, when the embossing densities of the first embossing and the second embossing are within the above-mentioned ranges, the toilet paper 10 has a moderate softness and a smooth surface, resulting in an excellent feel. Furthermore, when the embossing depth (50%) is within the above-mentioned range, the toilet paper 10 has a moderate thickness, improving the texture such as softness, while allowing the roll diameter of the toilet roll 100 to be kept compact. Furthermore, when the diameter (50%) of the embossed recesses is within the above-mentioned range, the smoothness of the toilet paper surface is improved, and burst strength can be maintained within a moderate range.

[0098] (Embossment for joining) 1(a), in an embodiment of the present invention, the toilet paper 10 may optionally be provided with bonding embossed portions 13 for bonding the constituent sheets 10a, 10c, and 10b to one another. The bonding embossed portions 13 are provided only in a partial area of ​​the paper surface to prevent ply peeling of the sheets 10a, 10c, and 10b that constitute the individual layers of the toilet paper 10, and define bonding areas that integrally bond the sheets 10a, 10c, and 10b.

[0099] 1(a), the bonding embossed portions 13 may be formed on both side edges in the width direction (CD direction) of the toilet paper 10 so as to extend along the longitudinal direction (MD direction). The pattern of the bonding embossed portions 13 formed in this manner is also particularly referred to as edge embossing.

[0100] The edge embossment is preferably provided so as not to overlap the center in the width direction (CD) of the toilet paper. This prevents the edge embossment from degrading the texture of the center of the toilet paper surface. The edge embossment may be provided, for example, within a range of 10 to 50 mm from each edge in the width direction of the toilet paper.

[0101] In the edge embossing, the group of multiple bonding embossed portions 13 may be provided continuously in the longitudinal direction, or may be provided intermittently in the longitudinal direction.

[0102] The bonding embossed portions 13 are preferably formed so as not to protrude outward in the thickness direction from either the front or back of the toilet paper 10. By doing so, the surfaces of the bonding embossed portions 13 on both the front and back of the toilet paper become recesses that are at the same level as the surface of the toilet paper or have a height (depth) that is less than that, so the smooth feel of the surface of the toilet paper is not impaired.

[0103] When the toilet paper 10 is a four-ply or more toilet paper made up of four or more overlapping sheets, a bonding embossment (edge ​​embossment) to prevent ply separation may be applied to stacks of several sheets at a time, and then the stacks of several sheets thus bonded together, or the stacks of several sheets thus bonded and a single sheet may be ply-processed using an adhesive. However, in an embodiment of the present invention, the bonding embossment (edge ​​embossment) to prevent ply separation is preferably applied to all of the four or more sheets at once. By performing bonding embossing on all of the multi-ply sheets at once, there is no need to use ply glue to bond the plies, which can improve manufacturing efficiency.

[0104] (Tear-off perforations) In an embodiment of the present invention, the toilet paper 10 may optionally have tearing perforations (not shown) extending in the width direction of the toilet paper at regular intervals along the length of the toilet paper 10, in order to facilitate separation of the toilet paper 10 from the toilet roll 100 after it has been pulled out. These regular intervals along the length are set to, for example, 100 to 300 mm, taking into consideration the amount of paper needed when using the toilet and ease of use, but are not limited to this and can be set as desired.

[0105] The number, dimensions, widthwise distribution, etc. of the tear perforations are determined so that the toilet paper 10 does not tear unintentionally and so that the toilet paper 10 easily tears when a shear force is applied to the toilet paper 10. From the perspective of ease of tearing, the tear perforations preferably extend through the thickness of the toilet paper 10 and across both widthwise edges of the toilet paper 10. The tear perforations can be created using any known perforation processing device.

[0106] (tensile strength) In an embodiment of the present invention, the dry tensile strength Tm of the toilet paper 10 in the longitudinal direction (machine direction, MD) is not limited, but is preferably 2.00 N or more and 5.50 N or less, and more preferably 3.50 N or more and 5.00 N or less.

[0107] In an embodiment of the present invention, the dry tensile strength Tc of the toilet paper 10 in the width direction (cross direction, CD) is not limited, but is preferably 4.80 N or less, and more preferably 1.60 N or more and 4.80 N or less.

[0108] When the dry tensile strengths Tm and Tc are within the above ranges, the toilet paper is soft and feels good to the touch, has appropriate strength, and is less likely to tear when pulled out from the toilet roll.

[0109] (Tensile strength ratio (Tc / Tm) Tc / Tm, calculated as the ratio of the dry tensile strength Tm in the longitudinal direction of the toilet paper 10 to the dry tensile strength Tc in the width direction of the toilet paper 10, is preferably 46.1 or more and 80.0 or less, more preferably 48.0 or more and 78.0 or less, and even more preferably 50.0 or more and 75.0 or less.

[0110] When the tensile strength ratio Tc / Tm is within the above range, the aspect ratio is small, the bursting strength can be kept within an appropriate range, and the toilet paper can be made more resistant to tearing.

[0111] (geometric mean tensile strength) The geometric mean of the tensile strength of the toilet paper is calculated as the square root of the product of the dry tensile strength Tm in the longitudinal direction of the toilet paper 10 and the dry tensile strength Tc in the width direction of the toilet paper, √(Tm×Tc).

[0112] The geometric mean √(Tm×Tc) of the tensile strength of the toilet paper 10 is 2.40 N or more and 4.50 N or less, preferably 2.45 N or more and 4.40 N or less, and more preferably 2.50 N or more and 4.20 N or less.

[0113] When the geometric mean of the tensile strength of the toilet paper 10 is within the above range, the toilet paper 10 has sufficient strength while also being soft, making it difficult to tear and providing an excellent feel to the touch.

[0114] (Method for measuring tensile strength) The tensile strength of toilet paper in this specification is a value obtained by cutting a sample of toilet paper long enough to meet a width of 15 mm and a span length of 100 mm, measuring it at a pulling speed of 50 mm / min, and calculating the average of 10 measurements. The tensile strength (longitudinal) is measured with the longitudinal direction of the toilet paper as the span length direction and the width direction of the toilet paper as the width direction of the sample. The tensile strength (transverse) is measured with the width direction of the toilet paper as the span length direction and the longitudinal direction of the toilet paper as the width direction of the sample. For example, a horizontal tensile tester (manufactured by Kumagai Riki Kogyo Co., Ltd.) can be used to measure tensile strength. The tensile strength in the examples described below was measured in an environment conforming to ISO187 (temperature 23±1°C, relative humidity 50±2%).

[0115] The tensile strength can be controlled by changing the ratio of the pulp components and the degree of beating. For example, when softwood pulp (N) and hardwood pulp (L) are used together as the pulp components of sheets 10a, 10c, and 10b that make up toilet paper 10, the tensile strength in the longitudinal direction (machine direction, MD) can be increased by increasing the N / L ratio. Furthermore, the tensile strength in the longitudinal direction and cross direction (transverse direction, CD) can be increased by increasing the degree of beating of the pulp components (reducing freeness).

[0116] (TSA measurements) Techniques for quantifying parameters that serve as indicators of three characteristics that affect the human feel (touch) of toilet paper—softness, smoothness / roughness, and stiffness—through acoustic and deformation measurements using a tissue softness measuring device (TSA) are disclosed in several patent documents, such as JP 2023-106059 A. Methods for measuring TS7 and TS750 values ​​using a tissue softness measuring device (TSA) and the measuring devices used are described in more detail in, for example, JP 2023-106059 A and Japanese Patent No. 7006755. For details of various measurement methods using a tissue softness measuring device (TSA), please refer to the above patent documents.

[0117] The TS7 value and TS750 value can be measured, for example, by a tissue softness measuring device TSA (manufactured by emtec; Tissue Softness Analyzer).

[0118] The TS7 value is a parameter that primarily indicates "softness," one of the three characteristics of toilet paper. Specifically, the intensity (amplitude) of the maximum peak in a single spectrum based on the horizontal movement of the measuring device's blade serves as an indicator of "softness." A lower TS7 value indicates a softer and fluffier feel (surface softness and bulk softness), and the sample is evaluated as softer. Specifically, when the raised fibers, which are protrusions originating from the constituent fibers of the sample's measurement surface, come into contact with the TSA measuring device's blade, horizontal vibration of the blade is induced according to the bending of the raised fibers. For example, softer raised fibers bend more, resulting in a relatively smaller amplitude of the blade's horizontal vibration and a smaller TS7 value. The amplitude of the blade's horizontal vibration depends on the softness and hardness of the raised fibers (the rigidity of individual fibers), the internal structure of the sample material (bulk, fiber bonding strength), micro- and macro-compressibility, and added chemicals (softeners, starch, dry strength agents). Therefore, the TS7 value can be controlled by changing these factors.

[0119] The TS750 value is a parameter that primarily indicates "smoothness / roughness" of the three toilet paper characteristics mentioned above. During measurement, when the measuring device's blade moves horizontally, the sample's position fluctuates depending on the structural dimensions of the sample pressed by the blade (for example, dimensions resulting from the toilet paper's creep or embossing), inducing vertical vibration of the sample. The induced vibration frequency depends on the structural dimensions of the sample and the blade's rotation speed, and the vibration amplitude (strength) depends on the structural height. The lower the TS750 value, the better the smoothness tends to be.

[0120] (TS7 external surface) In this specification, the TS7 outer surface is the intensity (TS7 value) of the maximum peak in the spectrum containing a frequency of 6500 Hz, obtained by using a tissue softness measuring device TSA to measure the vibration of a toilet paper sample placed on a sample stage with the outer surface 10A of the roll (i.e., the measurement surface) facing up, by pressing a bladed rotor from above with a pressing pressure of 100 mN and then rotating the sample stage at a rotation speed of 2.0 per second, and measuring the vibration of the sample stage with a vibration sensor.

[0121] In an embodiment of the present invention, the TS7 outer surface is preferably 25.0 dBV 2 ms or less, and more preferably 10.0 dBV 2 ms or more 25.0dBV 2 In an embodiment of the present invention, the TS7 external face is 25 dBV 2 When the hardness is 10 ms or less, the outer surface 10A of the roll of toilet paper 10 has good softness.

[0122] (TS7 interior) In this specification, the TS7 inner surface is the intensity (TS7 value) of the maximum peak in the spectrum containing a frequency of 6500 Hz, obtained by using a tissue softness measuring device TSA to measure the vibration of a toilet paper sample 10 placed on a sample stage with the inner surface 10B of the roll facing up, by pressing a bladed rotor from above with a pressing pressure of 100 mN, and then rotating the sample stage at a rotation speed of 2.0 rpm. In an embodiment of the present invention, the TS7 inner surface is preferably 12.0 dBV. 2 ms or more 25.0dBV 2 ms or less, and more preferably 15.0 dBV 2 ms or more 23.0dBV 2 ms or less. If the TS7 inner surface value is within this range, the surface of the toilet paper will be soft and comfortable against the skin.

[0123] (TS7 inner surface / TS7 outer surface) In an embodiment of the present invention, the ratio of the above-mentioned TS7 inner surface to the TS7 outer surface, that is, the ratio of the TS7 inner surface to the TS7 outer surface, is measured by a tissue softness measuring device TSA. A toilet paper sample is placed on a sample stage with the inner surface 10B of the roll facing up, and a bladed rotor is pressed from above with a pressing pressure of 100 mN, and then rotated at a rotation speed of 2.0 per second. The vibration of the sample stage is measured with a vibration sensor. The ratio is the intensity of the maximum peak (TS7 value) of the spectrum containing a frequency of 6500 Hz. Using the TSA device, a toilet paper sample is placed on a sample stage with the outer surface 10A of the roll facing up, and a bladed rotor is pressed from above with a pressing pressure of 100 mN, and then rotated at a rotation speed of 2.0 per second. The vibration of the sample stage is measured with a vibration sensor, and the ratio R (TS7 inner surface / TS7 outer surface), which is the intensity of the maximum peak (TS7 value) of the spectrum containing a frequency of 6500 Hz, to the TS7 outer surface, is 0.85 or more, preferably 0.90 or more, and more preferably 0.95 or more. If the ratio R (TS7 inner surface / TS7 outer surface) is within the above range, the toilet paper will have no noticeable difference in softness between the front and back surfaces when being wound up.

[0124] (TS750 external surface) In this specification, the TS750 outer surface is the intensity of the first maximum peak (TS750 value) of the spectrum seen from the low frequency side, obtained by using a tissue softness measuring device TSA to measure the vibration of a toilet paper 10 placed on a sample stage with the outer surface 10A of the toilet roll 100 facing up, by pressing a bladed rotor from above with a pressing pressure of 100 mN, and then rotating the sample stage at a rotation speed of 2.0 per second. In an embodiment according to the present invention, the TS750 outer surface is preferably 10 dBV. 2 rms over 35dBV 2 rms or less, preferably 12 dBV 2 rms over 30dBV 2 rms or less, and more preferably 15 dBV 2 rms over 28dBV 2 is less than rms.

[0125] When the TS750 outer surface is within the above range, the outer surface 10A of the toilet paper 10 is smooth and has an excellent texture. If the TS750 outer surface is too small, it will have a slippery texture, and if it is too large, it will be less smooth and the texture may be poor.

[0126] (TS750 interior) In this specification, the TS750 inner surface is the intensity (TS750 value) of the first maximum peak in the spectrum seen from the low frequency side, obtained by using a tissue softness measuring device TSA to measure the vibration of a toilet paper 10 placed on a sample stage with the inner surface 10B of the toilet roll 100 facing up, by pressing a bladed rotor from above with a pressing pressure of 100 mN, and then rotating the sample stage at a rotation speed of 2.0 per second. In an embodiment according to the present invention, the TS750 inner surface is preferably 10 dBV. 2 rms over 30dBV 2 rms or less, preferably 12 dBV 2 rms over 28dBV 2 rms or less, and more preferably 15 dBV 2 rms over 26dBV 2 is less than rms.

[0127] When the TS750 inner surface is within the above range, the inner surface 10B of the toilet paper 10 is smooth and has an excellent texture. If the TS750 inner surface is too small, the texture approaches a slippery feel, and if it is too large, the smoothness decreases and the texture may deteriorate.

[0128] (TS750 inside / TS750 outside) In an embodiment of the present invention, the ratio of the above-mentioned TS750 inner surface to the TS750 outer surface, that is, the ratio of the TS750 inner surface to the TS750 outer surface, is measured by a tissue softness measuring device TSA. The toilet paper 10 is placed on a sample stage with the inner surface 10B of the toilet roll 100 facing up, and a bladed rotor is pressed from above with a pressing pressure of 100 mN, and then rotated at a rotation speed of 2.0 per second. The vibration of the sample stage is measured with a vibration sensor. The ratio is the intensity of the first maximum peak (TS750 value) of the spectrum seen from the low frequency side. Using a TSA measuring device, a toilet paper roll 10 is placed on a sample stage with the outer surface 10A of the toilet roll 100 facing up, and a bladed rotor is pressed from above with a pressing pressure of 100mN, and then rotated at a rotation speed of 2.0 per second. The vibration of the sample stage is measured with a vibration sensor, and the ratio R (TS750 inner surface / TS750 outer surface), which is the intensity of the first maximum peak (TS750 value) of the spectrum viewed from the low frequency side, to the TS750 outer surface, is 0.85 or more, preferably 0.89 or more, and preferably 0.92 or more.

[0129] When the ratio R (TS750 inner surface / TS750 outer surface) is within the above range, the embossed texture is smooth and there is little sense of unevenness, resulting in toilet paper that does not feel different between the front and back when used.

[0130] (Examples of toilet roll manufacturing method and manufacturing equipment according to an embodiment of the present invention) An example of a method and equipment applicable to manufacturing the toilet roll 100 according to an embodiment of the present invention will be described with reference to Figure 4. The toilet roll 100 can be manufactured, for example, as follows. In this example, a toilet roll 100 consisting of four plies of toilet paper 10 with the layer structure shown in Figure 2 (b-1) will be manufactured.

[0131] (Manufacturing raw rolls) Primary raw rolls (not shown) are manufactured to produce each of the sheets 10a, 10c1, 10c2, and 10b that are components of the toilet paper 10. In detail, a papermaking machine (not shown) is used to make and wind wide, long sheets (several times to twenty-odd times the width of the toilet roll) from papermaking slurry (paper stock), to manufacture the primary raw rolls (not shown) for the sheets 10a, 10c1, 10c2, and 10b.

[0132] As the paper machine, for example, known paper machines such as twin wire former, cylinder former, suction press former, and crescent former can be used.

[0133] The papermaking machine may be equipped with a creping section that performs creping. In the creping section, during the raw roll manufacturing process, a creping doctor can impart very fine wavy wrinkles called crepes to the sheet as needed while the sheet (web) being made is being dried. Creping can impart softness, bulkiness (bulk), absorbency, aesthetic appearance (crepe shape), and a pleasant feel to the sheet.

[0134] The paper machine may also be equipped with a calendering unit. In the calendering unit, the dried sheet may be subjected to calendering treatment, in which a pair of calender rolls sandwich and press the sheet from above and below, as needed. This compresses the sheet, adjusting and uniforming the paper thickness, and smoothing the surface. The calendering unit may be provided separately from the paper machine, and calendering may be performed in any manufacturing process after the raw roll manufacturing process. Calendering may be performed in multiple stages.

[0135] (Toilet roll manufacturing) 4 is a schematic diagram showing an example of a manufacturing facility applicable to the manufacture of the toilet roll 100 according to an embodiment of the present invention. The method described below and the manufacturing facility shown in FIG. 4 are for illustrative purposes only and do not limit the present invention.

[0136] In this example, a toilet roll 100 is manufactured from four plies of toilet paper 10 having the layer structure shown in (b-1) of Figure 2. Also, in this example, the toilet roll 100 is manufactured using two secondary raw rolls R1 and R2.

[0137] A two-ply laminated sheet L1 (hereinafter also simply referred to as sheet L1) made by overlapping sheets drawn from two primary raw rolls (not shown) is wound up in advance using a known plying machine or winder, etc. to produce a secondary raw roll R1. Similarly, a two-ply laminated sheet L2 (hereinafter also simply referred to as sheet L2) made by overlapping sheets drawn from two primary raw rolls (not shown) is wound up in advance using a known plying machine or winder, etc. to produce a secondary raw roll R2.

[0138] The secondary web rolls R1 and R2 are rotatably attached to a web roll stand 70, and are driven to rotate by a web sheet feeding device (not shown) to feed out the sheets L1 and L2.

[0139] Each of the sheets L1 and L2 is a two-ply sheet made up of two sheets of the same or different paper quality superimposed on one another. The sheets L1 and L2 may be the same or different laminated sheets.

[0140] The sheets L1 and L2 unwound from the secondary raw rolls R1 and R2 are transported to an embossing unit 76 located downstream of the raw roll stand 70. Downstream of the embossing unit 76, a winding unit 77 and an end processing unit 78 are further located in this order.

[0141] The embossing unit 76 is, in short, a unit that embosses the sheets L1 and L2 to form embossed sheets.

[0142] The embossing section 76 includes an embossing roll unit 71 and a bonding embossing roll unit 75 .

[0143] The embossing roll unit 71 has an embossing roll and a backup roll. The embossing roll of the embossing roll unit 71 is rotatable, and has an outer peripheral surface formed with a concave-convex pattern corresponding to the embossing recesses 12 shown in FIG. 1.

[0144] A rotatable guide roller 73 for guiding the sheet to the embossing roll unit 71 is provided on the upstream side of the embossing roll unit 71 .

[0145] A bonding embossing roll unit 75 is disposed downstream of the embossing roll unit 71. The bonding embossing roll unit 75 has an embossing wheel and a backing roll that face each other. The backing roll is rotatable so as to rotate synchronously with the embossing roll of the embossing roll unit 71, and an embossing pattern corresponding to the bonding embossing section 13 is formed on the outer circumferential surfaces of the embossing wheel and the backing roll.

[0146] An embossing roll unit 79 similar to the embossing roll unit 71 is provided upstream of the bonding embossing roll unit 75 .

[0147] The embossing roll unit 79 has an embossing roll and a backup roll. The embossing roll of the embossing roll unit 79 is rotatable, and has an outer peripheral surface formed with a concave-convex pattern corresponding to the embossing recesses 15 shown in FIG. 1.

[0148] On the upstream side of the embossing roll unit 79, a rotatable guide roller 72 for guiding the sheet to the embossing roll unit 79 is provided.

[0149] Sheet L1 (i.e., a sheet stack including the second embossed sheet) that has passed through embossing roll unit 71 and been embossed (second embossing) and sheet L2 (i.e., a sheet stack including the first embossed sheet) that has passed through embossing roll unit 79 and been embossed (first embossing) are superimposed on each other on guide roller 74. Next, sheets L1 and L2 are superimposed on each other to form laminated sheet L3, which is passed between the embossing wheel and backing roll of bonding embossing roll unit 75 and wrapped around the backing roll. At this time, if necessary, the embossing wheel is pressed against the rotating backing roll with a predetermined pressure by a fluid pressure cylinder, thereby subjecting laminated sheet L3 to bonding embossing and providing bonding embossed portions 13 to prevent ply peeling.

[0150] The bonding embossment 13, which is provided in a portion of the sheet to prevent ply separation, is optional and not essential in embodiments of the present invention. However, in the present invention, the number of plies of the toilet paper 10 is three or more, and as the number of plies increases, ply separation tends to occur more easily. Therefore, when the number of plies is four or more, bonding embossment is preferably provided to prevent ply separation of the sheet in the toilet paper 10. The bonding embossment is preferably provided on all sheets of the multi-ply of multi-ply toilet paper at once.

[0151] In this example, at least the uneven portions of the embossing rolls of the embossing roll unit 71 and the embossing roll unit 79 and the bonding embossing roll unit 75 are formed of metal, but the surface portion of the backup roll is formed of a hard rubber-like elastic material such as elastically deformable hard synthetic rubber.

[0152] In this way, wide toilet paper L3, which is a laminated sheet in which sheet L1 (a laminate including the second embossed sheet) and sheet L2 (a laminate including the first embossed sheet) are laminated, is formed in the embossing unit 76. The wide toilet paper L3 is sent to the winding unit 77 located downstream thereof.

[0153] In the winding section 77, the leading end of the wide toilet paper L3 delivered from the embossing section 76 is wound around the wide (i.e., axially long) paper tube 14L, which is the core, via adhesive (pickup glue).

[0154] A predetermined length of the wide toilet paper L3 is wound around the paper tube 14L to form a roll 86 that will become a wide toilet roll 100L (i.e., a large dimension in the CD direction), and the end of the wide toilet paper L3 is cut off by cutting means (not shown). The resulting roll 86 is sent to the end processing section 78.

[0155] The end processing section 78 glues the end of the end of the roll 86 delivered from the winding section 77 to the surface (outer circumferential surface of the roll) of the roll 86 with adhesive (tail seal glue) to form a wide toilet roll 100L, preventing the wide toilet roll 100L from unwinding.

[0156] Prior to cutting the wide toilet paper L3 into predetermined lengths in the winding section 77, tearing perforations that traverse the width of the wide toilet paper L3 may be formed at regular intervals along the longitudinal direction (MD direction) of the wide toilet paper L3. Any known perforation forming means can be used to form the tearing perforations. The formation of such tearing perforations is optional and not essential in the embodiment of the present invention.

[0157] The wide toilet roll 100L is then transported from the end processing section 78 to a cutting section (not shown) where it is cut into individual toilet rolls 100 at a predetermined width according to product specifications, etc.

[0158] Meanwhile, in the winding section 77, the tip end of the wide toilet paper L3 (i.e., the end of the wide toilet paper L6 on the original roll side) produced by cutting the wide toilet paper L3 at predetermined lengths is wound around a new axially long core (wide paper tube 14L) arranged in the winding section 77 via adhesive, and the wide toilet paper L3 is again wound around this axially long core by a predetermined length.

[0159] The above-described manufacturing method and manufacturing apparatus are merely examples, and do not limit the manufacturing method according to the present invention or applicable manufacturing apparatus.

[0160] In the above example, two 2-ply secondary raw rolls R1 and R2 were mounted on the manufacturing apparatus of FIG. 4, and sheets L1 and L2 were stacked within the apparatus of FIG. 4. Here, in the manufacturing apparatus shown in FIG. 4, the secondary raw rolls R1 and R2 do not necessarily have to be 2-ply rolls; by changing the number of plies of the sheet wound around each of the secondary raw rolls R1 and R2, toilet paper having the configuration illustrated in FIG. 2 can be similarly obtained. Furthermore, the number of secondary raw rolls is not limited to two, as long as the desired number of plies and ply configuration can ultimately be obtained. Instead of the secondary raw rolls, one-ply primary raw rolls may be used for the required number of plies.

[0161] Alternatively, in the winding section 77, instead of the toilet roll 100L, a roll with a longer winding length may be formed, and this may be used as a tertiary roll and loaded onto another device with a winding function, such as a winder, to produce a toilet roll through a process of forming a log of a predetermined length.

[0162] <Method for manufacturing toilet roll according to an embodiment of the present invention> A method for manufacturing a toilet roll according to an embodiment of the present invention, in which multi-ply toilet paper is wound into a roll, is formed by stacking three or more sheets, each sheet including a first embossed sheet having a first embossment and a second embossed sheet having a second embossment different from the first embossment. The method generally includes the following steps. (a) The density of the embossed recesses in the first embossing is 15.0 pieces / cm 2 More than 35.0 pieces / cm 2 A step of preparing a first embossed sheet (i.e., in the example of FIG. 4, an embossing step for the sheet L2 in the embossing roll unit 79), which is as follows: (b) The density of the embossed depressions in the second embossing is 40.0 / cm 2 More than 80.0 pieces / cm 2 A step of preparing a second embossed sheet (i.e., in the example of FIG. 4, an embossing step for the sheet L1 in the embossing roll unit 71), which is as follows: (c) stacking three or more sheets so that the first embossed sheet and the second embossed sheet are disposed on opposite sides of the toilet paper (i.e., in the example of FIG. 4, stacking at guide roller 74); and (d) A process of winding three or more stacked sheets into a toilet paper roll so that the first embossed sheet is positioned on the outermost side of the toilet roll and the second embossed sheet is positioned on the innermost side of the toilet roll (i.e., in the example of Figure 4, a winding process in the winding section 77).

[0163] The manufacturing method according to an embodiment of the present invention may include one or more of the following steps before the above steps (a) and (b) (where p and q are each an integer of 1 or greater, and p+q is the number of plies in the multi-ply toilet paper): (x) forming a sheet; (y) preparing a p-ply sheet L1 consisting of p sheets; (z) A step of preparing a sheet L2 of q plies consisting of q sheets.

[0164] In the manufacturing method according to the embodiment of the present invention, after the step (b), (z) A process of cutting the manufactured toilet roll to a product width; may also include:

[0165] Furthermore, the manufacturing method according to the embodiment of the present invention may include or omit steps other than those described above as necessary, as long as the effects of the present invention can be achieved.

[0166] For example, either or both of the first and second embossing processes described above may be carried out in advance by a separate processing machine.

[0167] The present invention should be interpreted only from the matters described in the claims, and even in the above-described embodiments, all changes and modifications encompassed by the concept of the present invention are possible in addition to the matters described. In other words, all matters in the above-described embodiments are not intended to limit the present invention, and can be arbitrarily changed depending on the application or purpose, including all configurations not directly related to the present invention. [Example]

[0168] Papermaking was performed using the same papermaking slurry (stock) containing softwood bleached kraft pulp (NBKP) and hardwood bleached kraft pulp (LBKP), and multiple primary rolls were wound with the sheets produced. Two of the primary rolls were used to stack sheets unwound from each primary roll using a known plying machine to obtain a two-ply secondary roll R1. Similarly, another two-ply secondary roll R2 was obtained. Using the manufacturing equipment shown in Figure 4 and the manufacturing method described above, a two-ply sheet L1 unwound from the secondary roll R1 was subjected to a second embossing process, and a two-ply sheet L2 unwound from the secondary roll R2 was subjected to a first embossing process. These sheets L1 and L2 were then stacked to form a laminated sheet L3, producing a toilet roll. As a result, toilet paper having a layer structure as shown in (b-1) of Figure 2 was wound up so that the side having the second embossed depressions was on the inside of the roll as shown in (a) of Figure 1, and the toilet paper having the first embossed depressions was on the outside of the roll, thereby obtaining 4-ply toilet paper rolls of Examples 1 to 10 and Comparative Examples 1 and 2.

[0169] In Examples 1 to 3, 5 to 10, and Comparative Examples 1 and 2, the papermaking slurry used a pulp composition of NBKP:LBKP = 50% by mass:50% by mass. In Example 4, the pulp composition of NBKP:LBKP = 60% by mass:40% by mass. The beating degree of the pulp was as shown in the table.

[0170] The toilet rolls of the Examples and Comparative Examples were subjected to the following measurements and evaluations. The measurements were carried out in an environment conforming to Japanese Industrial Standard JIS P8111 (temperature 23±1°C, humidity 50±2% RH) by conditioning the samples.

[0171] <Measurement> [Toilet roll length [m]] While unwinding the toilet paper from the manufactured toilet roll, the length of the toilet paper wound around the paper tube was measured from the end (0% position) to the beginning (100% position). Measurements were taken in 1m increments and any fractional parts were rounded down.

[0172] [Toilet roll diameter [mm]] The outer diameter of the produced toilet roll was measured with a vernier caliper and rounded off to the nearest whole number.

[0173] [winding density [m / cm 2 ] It was calculated according to the following formulas (I) and (II). (Roll density) = (Roll length x number of plies) ÷ (cross-sectional area of ​​toilet roll) (I) (Cross-sectional area) = (Toilet roll diameter DR ÷ 2) 2 ×3.14-(core diameter DC÷2) 2 ×3.14···(II)

[0174] [Toilet roll width [mm]] The roll width of the produced toilet roll was measured with a vernier caliper and rounded off to the nearest whole number.

[0175] [Core diameter of paper tube [mm]] The outer diameter of the paper tube of the produced toilet roll was measured with a vernier caliper and rounded off to the nearest whole number.

[0176] [Roll mass [g]] Each manufactured toilet roll was placed on a scale and the mass of the toilet roll was measured.

[0177] [Mass of paper tube [g]] Each paper tube removed from the toilet roll was placed on a scale and the mass of the paper tube was measured.

[0178] [Mass of roll (excluding the mass of the paper core) [g]] The mass was calculated by subtracting the mass of the paper tube (actual measured value) from the mass of the toilet roll (actual measured value).

[0179] [Roll density [g / cm 3 ] The density of the toilet roll was calculated according to the following formula (V). (Density) = (Mass of toilet roll (excluding the mass of the paper core)) ÷ {(Cross-sectional area of ​​toilet roll) × (Width of toilet roll W)} (V)

[0180] [Basis weight (per sheet) [g / m 2 ] The toilet paper was pulled out from the toilet roll, and the basis weight of the 4-ply toilet paper was measured in accordance with Japanese Industrial Standard JIS P8124, and divided by the number of plies, 4, to determine the basis weight per sheet. Specifically, the 4-ply toilet paper was conditioned according to the method specified in Japanese Industrial Standard JIS P8111, and the conditioned 4-ply toilet paper was cut into a 10 cm x 10 cm piece with the four sheets still stacked, and the weight of the cut-out 4-ply toilet paper was measured, and the weight was multiplied by 0.01 m of the cut-out area of ​​the 4-ply toilet paper. 2 The basis weight of the four-ply toilet paper was measured by dividing by 4, the number of plies, to determine the basis weight per sheet.

[0181] [Toilet paper thickness [μm]] After conditioning the humidity in accordance with Japanese Industrial Standard JIS P8111, the toilet paper was pulled out from the toilet roll and the thickness of the toilet paper was measured in accordance with ISO12625-3.

[0182] [Embossing depth (50%) [μm]] According to the above-mentioned method of measuring and calculating the difference in height of the embossing using a shape measurement laser microscope, the embossing depth (μm) of the embossed recesses at the 50% position was measured for the surface of the toilet paper that is on the outside of the toilet roll (outer surface of the roll) and the surface of the toilet paper that is on the inside of the roll (inner surface of the roll).

[0183] [Embossing density (inner surface, outer surface) [pieces / cm 2 ] The embossing density was calculated by counting the number of embossed depressions in a 10 cm x 10 cm area of ​​the sample and converting it to per 1 cm x 1 cm, and the average value for five locations in the 10 cm x 10 cm area was calculated.

[0184] [Embossment diameter [μm]] According to the above-mentioned method using a shape measuring laser microscope, the diameter (μm) of the embossing of the embossed depressions at the 50% position was measured for the surface of the toilet paper on the outside of the toilet roll (outer surface of the roll) and the surface of the toilet paper on the inside of the roll (inner surface of the roll).

[0185] [Tensile strength (Tm, Tc)] Toilet paper was cut into long samples with a width of 15 mm and a span length of 100 mm, and measurements were taken at a tensile speed of 50 mm / min, with the average of 10 measurements calculated. Tensile strength (Tm: longitudinal) was measured with the longitudinal direction of the toilet paper as the span length direction and the width direction of the toilet paper as the width direction of the sample. Tensile strength (Tc: transverse) was measured with the width direction of the toilet paper as the span length direction and the longitudinal direction of the toilet paper as the width direction of the sample. A horizontal tensile tester (manufactured by Kumagai Riki Kogyo Co., Ltd.) was used to measure tensile strength. Tensile strength measurements were taken in an environment conforming to ISO 187 (temperature 23±1°C, relative humidity 50±2%).

[0186] [Tensile strength ratio (Tc / Tm)] The tensile strength ratio (Tc / Tm), which is the aspect ratio of the tensile strength of the toilet paper, was calculated as the dry tensile strength Tc (percentage) of the toilet paper in the width direction relative to the dry tensile strength Tm of the toilet paper in the length direction.

[0187] [Geometric mean of tensile strength (√(Tm×Tc))] The geometric mean of the tensile strength of the toilet paper was calculated as the square root of the product of the dry tensile strength Tm of the toilet paper in the longitudinal direction and the dry tensile strength Tc of the toilet paper in the cross direction, √(Tm × Tc).

[0188] [TS7 value] Using the TSA tissue softness measuring device, a toilet paper sample was placed on a sample stage with the measurement surface facing up. A bladed rotor was pressed from above with a pressure of 100 mN, and the sample was then rotated at a speed of 2.0 revolutions per second. The vibration of the sample stage was measured with a vibration sensor, and the TS7 value, which is the intensity of the maximum peak in the spectrum containing a frequency of 6500 Hz, was determined. The TS7 value when the surface of the toilet paper on the outside of the toilet roll was used as the measurement surface, was defined as the TS7 outer surface, and the TS7 value when the surface of the toilet paper on the inside of the toilet roll was used as the measurement surface, was defined as the TS7 inner surface. The ratio R (TS7 inner surface / TS7 outer surface) was also calculated from the obtained TS7 inner and TS7 outer surfaces.

[0189] [TS750 value] Using the TSA tissue softness analyzer, a toilet paper sample was placed on a sample stage with the measurement surface facing up. A bladed rotor was pressed from above with a pressure of 100 mN, and the sample was rotated at a speed of 2.0 revolutions per second. The vibration of the sample stage was measured with a vibration sensor, and the TS750 value, which is the intensity of the first maximum peak in the spectrum seen from the low-frequency side, was calculated. The TS750 value when the surface of the toilet paper on the outside of the toilet roll was used as the measurement surface was taken as the TS750 outer surface, and the TS750 value when the surface of the toilet paper on the inside of the toilet roll was used as the measurement surface was taken as the TS750 inner surface. The ratio R (TS750 inner surface / TS750 outer surface) was also calculated from the obtained TS750 inner and TS750 outer surface values.

[0190] <Evaluation> Sensory evaluation was carried out for the following items, and the results were indicated by symbols.

[0191] [The feel of toilet paper] Six testers evaluated the feel of the toilet paper by examining the feel of both sides of the toilet paper when pulling it out from the toilet rolls of the Examples and Comparative Examples. The evaluation was based on the feel of softness, which is a combination of surface roughness, unevenness, strength, smoothness, etc., and was ranked from best to worst as ◯: good, △: fair, ×: bad.

[0192] [Toilet paper tear resistance] An unused toilet roll was placed in a toilet paper holder, and tear resistance was evaluated based on whether or not tearing occurred when a 1-meter length of toilet paper was pulled out from the outer end of the roll at the beginning of use. 30 toilet rolls were prepared for each type of sample, and six experimenters each tested five toilet rolls per type of sample. For each sample, the number of toilet rolls that had tears was counted, and a total of 3 or less was marked with a circle, 4 to 6 with a triangle, and more than 6 with an x. The fewer the number of toilet rolls that had tears, the less likely the toilet paper was to tear when pulled out from the toilet roll, and the more preferable it was.

[0193] Table 1 shows the test results.

[0194] [Table 1]

[0195] As shown in Table 1, the toilet rolls of the Examples and Comparative Examples were all toilet rolls in which four sheets of toilet paper were overlapped and wound into a roll.

[0196] The dry tensile strengths of Comparative Examples 1 and 2 in the longitudinal direction were low at 2.33 N and 1.70 N, respectively, and the toilet paper was prone to tearing when pulled out. In this case, the geometric mean of the dry tensile strengths in the longitudinal and transverse directions of the cited documents 1 and 2 was less than 2.40 N.

[0197] The toilet rolls of the examples were soft to the touch and did not tear easily when pulled out. The dry tensile strength of the toilet rolls of the examples in the longitudinal direction of the toilet paper was 3.50 N or more and 5.00 N or less. Furthermore, the geometric mean √(Tm × Tc), calculated as the square root of the product of the dry tensile strength Tm in the longitudinal direction of the toilet paper and the dry tensile strength Tc in the width direction of the toilet paper, was 2.40 N or more and 4.50 N or less. [Explanation of symbols]

[0198] 10. Toilet paper 10A outermost surface 10B Innermost 10a outermost sheet 10b Innermost sheet 10c mid-layer sheet 12 Embossment / embossed recess 13 Bonding embossing / edge embossing 100 toilet rolls a,b Longest part D Embossing depth DC Core Diameter DR winding diameter Erim L roll length W width

Claims

1. A toilet roll in which multi-ply toilet paper, in which three or more sheets are stacked, is wound into a roll, The basis weight per sheet of the three or more sheets is 10.0 g / m ２ 16.5g / m or more ２ is as follows: an outermost sheet of the three or more sheets positioned at the outermost side of the toilet roll is a first embossed sheet having a first embossment; an innermost sheet of the three or more sheets positioned at the innermost side of the toilet roll is a second embossed sheet having a second embossment different from the first embossment; The density of the embossed recesses of the first embossing in the outermost layer sheet is 15.0 pieces / cm ２ More than 35.0 pieces / cm ２ is as follows: The density of the embossed recesses of the second embossing in the innermost layer sheet is 40.0 pieces / cm ２ More than 80.0 pieces / cm ２ is as follows: The geometric mean √(Tm × Tc), calculated as the square root of the product of the dry tensile strength Tm in the longitudinal direction of the toilet paper and the dry tensile strength Tc in the width direction of the toilet paper, is 2.40 N or more and 4.50 N or less. A toilet roll.

2. The toilet roll according to claim 1, wherein the dry tensile strength Tm of the toilet paper in the longitudinal direction is 3.50 N or more and 5.00 N or less.

3. The toilet roll according to claim 1, wherein the ratio Tc / Tm of the dry tensile strength Tc in the width direction of the toilet paper to the dry tensile strength Tm in the longitudinal direction of the toilet paper is 50.0% or more.

4. The toilet roll according to claim 1, characterized in that, at a position where the toilet paper is unwound from the outer end of the roll to 50% of the winding length, the depth of the embossed depressions of the first embossing is 70 μm or more and 120 μm or less, and the depth of the embossed depressions of the second embossing is 60 μm or more and 100 μm or less.

5. The toilet roll according to claim 1, characterized in that the second embossings have dot shapes uniformly arranged over the entire surface of the second embossed sheet, and the diameter of the embossed depressions of the second embossings is 0.50 mm or more and 0.95 mm or less at a position where the toilet paper has been unwound from the outer end of the roll to 50% of the winding length.

6. Using a tissue softness measuring device (TSA), a toilet paper sample was placed on a sample stage with the inner surface of the roll facing up. A bladed rotor was pressed from above with a pressing pressure of 100 mN, and then rotated at a rotation speed of 2.0 per second. The vibration of the sample stage was measured with a vibration sensor. The TS7 inner surface, which is the intensity of the maximum peak (TS7 value) of the spectrum containing a frequency of 6500 Hz, was 12.0 dBV. ２ rms above 25.0dBV ２ 2. The toilet roll according to claim 1, wherein the rms is less than or equal to 1.

7. A method for producing a toilet roll in which multi-ply toilet paper is wound into a roll, the multi-ply toilet paper being made up of three or more sheets stacked together, the sheets including a first embossed sheet having a first embossment and a second embossed sheet having a second embossment different from the first embossment, the method comprising: The density of the embossed recesses of the first embossing is 15.0 pieces / cm ２ More than 35.0 pieces / cm ２ preparing the first embossed sheet, The density of the embossed recesses of the second embossing is 40.0 pieces / cm ２ More than 80.0 pieces / cm ２ preparing the second embossed sheet, overlapping the three or more sheets so that the first embossed sheet and the second embossed sheet are disposed on both sides of the toilet paper; A step of winding the three or more stacked sheets into a roll so that the first embossed sheet is located on the outermost side of the toilet roll and the second embossed sheet is located on the innermost side of the toilet roll; A method comprising:

8. A toilet roll in which multi-ply toilet paper, in which three or more sheets are stacked, is wound into a roll, The basis weight per sheet of the three or more sheets is 10.0 g / m ２ 16.5g / m or more ２ is as follows: an outermost sheet of the three or more sheets positioned at the outermost side of the toilet roll is a first embossed sheet having a first embossment; an innermost sheet of the three or more sheets positioned at the innermost side of the toilet roll is a second embossed sheet having a second embossment different from the first embossment; The density of the embossed recesses of the first embossing in the outermost layer sheet is 15.0 pieces / cm ２ More than 35.0 pieces / cm ２ is as follows: The density of the embossed recesses of the second embossing in the innermost layer sheet is 40.0 pieces / cm ２ More than 80.0 pieces / cm ２ is as follows: The toilet roll has a dry tensile strength Tm in the longitudinal direction of the toilet paper of 3.50 N or more and 5.00 N or less.

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