JP2026003037A - Toilet roll - Google Patents

Abstract

[Problem] To provide a toilet roll suitable for use in toilets with flushing functions that can be easily made into long lengths. [Solution] This problem is solved by a toilet roll in which two plies of toilet paper, each consisting of two sheets bonded together via an embossed recess, are wound around a paper tube, the roll diameter being 120 mm or less and the roll length being 34.5 to 50 m, the toilet paper having a first sheet and a second sheet with first and second recesses of different depths formed by embossing, the depth of the first recess being 0.17 to 0.23 mm, the depth of the second recess being shallower than the depth of the first recess, and the toilet paper being wound with the first sheet facing outward relative to the paper tube. [Selected Drawing] None

Description

The present invention relates to toilet rolls.

As flushing toilets become more common, there is a growing demand for toilet paper that is suitable for use in flushing toilets.

In toilets with flushing functions, the defecation and urination areas are washed with warm or cold water, so it is necessary to wipe off the feces and urine along with any moisture that has adhered to the skin during the flushing process.

Therefore, toilet paper is required to be able to wipe away moisture from skin, be highly absorbent, and provide a sense of security when wiping. Laminate embossing is known as a technique for improving the ability to wipe away moisture from skin. Laminate embossing is a technique in which embossed plies are laminated together with adhesive, which increases strength, thickness, and water penetration resistance.

On the other hand, toilet paper is generally sold commercially in the form of toilet rolls wound around paper tubes. In recent years, toilet rolls have become longer, with the length of toilet paper wound around the paper tubes increasing.

Patent No. 6021532 JP 2019-10366 A

However, toilet paper made with laminated embossing technology is too thick and is not suitable for long rolls as is.

On the other hand, reducing the basis weight of each ply to increase the length of the paper can reduce the softness, fluffiness, and smoothness of the texture. In particular, reducing the basis weight of toilet paper made using laminate embossing technology can make it more likely to feel crisp and stiff due to the adhesive.

Furthermore, when used as toilet rolls, the surface of the roll feels unpleasant to the touch, and users are more likely to perceive it as being harder.

The main objective of the present invention is to provide a toilet roll that has excellent wiping ability on moist skin, high absorbency, and a sense of security when wiping, and that is also suitable for long lengths of toilet paper with a texture that is soft, fluffy, and smooth, and that has a firmness to the roll that makes it clear that it is a long length, while also having an excellent feel to the touch on the roll surface.

The first solution to the above problem is
A toilet roll in which two sheets of toilet paper are adhered together via embossed recesses and wound around a paper tube,
The winding diameter is 120 mm or less, and the winding length is 34.5 to 50 m,
The toilet paper has a basis weight per ply of 13.5 to 16.0 g/m2 and a thickness of 180 to 225 μm for two plies,
The toilet paper,
a first sheet having a first recess and a second recess formed by embossing and having different depths, and a second sheet;
the first recess has an area of 1.00 to 22.0 ^mm2 and a depth of 0.17 to 0.23 mm;
The second recess has an area of 0.25 to 0.75 ^mm2 and a depth of 0.050 to 0.090 mm;
the embossing density of the first recesses is 4 to 14/cm ² and the embossing density of the second recesses is 2 to 11/cm ² ;
The first recess has an inner surface of the laminate bonded to the second sheet, and the inner surface of the second recess is not bonded to the second sheet;
The toilet paper is wound around the paper tube with the first sheet facing outward.
This toilet roll is characterized by the following:

The second method is
In the toilet roll according to the first aspect, the second sheet has recesses formed by embossing, and the recesses are shallower in depth than the first recesses formed in the first sheet.

The third method is
The toilet roll according to the first or second means has a roll winding density of 0.74 to 1.30 m/ ^cm² and a roll density of 0.12 to 0.18 g/ ^cm³ .

The fourth method is
The toilet roll according to any one of the first to third aspects has a roll compression degree of 0.66 to 1.50.

The fifth method is
The toilet paper is a toilet roll according to the first to fourth means, which is treated with an enzyme-based paper strength agent.

The sixth method is
The toilet paper is a toilet roll according to any one of the first to fifth means, which does not contain starch or cationic starch.

The present invention provides a toilet roll that has excellent wiping ability on moist skin, high absorbency, and a sense of security when wiping, and that is suitable for long lengths of toilet paper with a soft, fluffy, and smooth texture.The roll has a firmness that makes it clear that it is a long length, and the surface of the roll has an excellent feel to the touch.

1 is a perspective view of a toilet roll according to an embodiment of the present invention. FIG. FIG. 4 is a schematic diagram for explaining the procedure for measuring the embossing depth according to the present invention. FIG. 1 is a schematic diagram for explaining a method for measuring MMD according to the present invention.

Next, an embodiment of the present invention will be described in detail below with reference to the drawings.

As shown in Figure 1, the toilet roll according to this embodiment is a cylindrically shaped toilet paper roll in which two plies of water-disintegrable toilet paper 10, consisting of a first sheet and a second sheet, are wound around a paper tube (also called a tube core) 20. Note that water-disintegrability here refers to a disintegration rate of 100 seconds or less according to JIS P 4501.

While conventional two-ply toilet rolls have a roll length of around 20 to 25 m, the toilet roll according to this embodiment has a roll length of 34.5 to 55 m, preferably 38 to 50 m, and is sometimes referred to as a long product or a 1.5 to 2 times roll product.

On the other hand, the roll diameter L1 (diameter) of the toilet roll of this embodiment is 120 mm or less, preferably 107 to 119 mm. JIS P 4501 stipulates that the roll diameter L1 of a toilet roll must be 120 mm or less, and general holders for holding toilet rolls are manufactured based on this 120 mm standard. The toilet roll of this embodiment has a roll diameter of 120 mm or less and can be set in a general holder. Here, the roll diameter L1 is a value measured using a diameter ruler manufactured by Muratec KDS Corporation or an equivalent device. The measured value is the average value of measurements taken at three different locations in the width direction. Note that the average value for products from the same production lot is the average value of five rolls. Note that the roll width L2 of the toilet roll of this embodiment is not limited, but is preferably 100 to 130 mm. The outer diameter L3 of the cardboard core is also not limited, but is 34 to 42 mm.

Here, the impression of hardness when holding a toilet roll in the hand is influenced not only by whether the roll is dense or not, but also by the collapse of the recesses caused by embossing when the toilet paper is stretched and wound, as well as the physical properties and surface characteristics of the toilet paper. Therefore, the toilet roll according to this embodiment is a two-ply toilet paper with recesses caused by embossing. This toilet paper has a basis weight per ply of preferably 13.0 to 17.0 g/m ² , more preferably 13.5 to 16.0 g/m ² , and a thickness of the two plies of preferably 175 to 238 μm , more preferably 180 to 225 μm . Within these basis weight and thickness ranges, wiping performance on moist skin, high absorbency, and a sense of security when wiping can be sufficiently improved, and the feel of the roll surface against the skin can be improved when the winding length is increased.

The basis weight (grammage) is measured in accordance with JIS P 8124. Paper thickness is measured by first conditioning the test specimen thoroughly (usually for approximately 8 hours) under the conditions specified in JIS P 8111 (1998), and then measuring the two-ply specimen under the same conditions using a PEACOCK H-type dial thickness gauge (thickness measuring device) (manufactured by Ozaki Seisakusho). Specifically, after ensuring there is no dust or dirt between the plunger and the measuring table, the plunger is lowered onto the measuring table, the dial thickness gauge's scale is adjusted to zero, the plunger is then raised, the sample is placed on the testing table, and the plunger is opened to 700 μm. The lever is then lowered in one go, and the gauge reading is taken. During measurement, the plunger is simply placed on the test table, not pressed down. The 10 mm diameter circular flat surface of the plunger terminal is positioned perpendicular to the paper surface, and the load during paper thickness measurement is approximately 70 gf. The paper thickness is the average value obtained by measuring 10 times.

Furthermore, the first sheet in the toilet paper according to this embodiment has first and second recesses of different depths formed by embossing. The first and second recesses of this first sheet are both formed on the same surface, and the other surface preferably has convex portions corresponding to the first and second recesses. The first sheet is wound around the paper tube so that it faces outward. It is particularly preferable for the recessed surface to be on the outer surface.

Furthermore, this toilet paper may be two-ply, with the inner layer side of the first recess of the first sheet bonded to the inner layer side of the second sheet. The first sheet may be bonded to the inner layer side of the second sheet via an adhesive applied to the convex portions corresponding to the concave portions of the first sheet. Alternatively, the first sheet may be integrated by pressure bonding using an embossing process known as single embossing. Regardless of whether an adhesive is used or whether single embossing is used, when the first sheet and the second sheet are integrated,
Convex portions corresponding to only the first recesses of the first sheet or to both the first recesses and the second recesses may be formed on the outer surface of the second sheet. On the other hand, the inner laminate surface side of the second recesses is preferably not bonded to the second sheet with an adhesive. Although it is not necessary for the inner laminate surface side of all the first recesses to be bonded to the second sheet, it is desirable for all recesses to be bonded from the viewpoint of ply peeling.

When using an adhesive, either a water-based or oil-based adhesive may be used. However, preferred adhesives are water-soluble adhesives such as PVA (polyvinyl alcohol) and CMC (carboxymethyl cellulose). CMC, a cellulose-based water-soluble adhesive, is particularly desirable.

The adhesive itself can be an ink with adhesive properties, or a coloring component such as a pigment or dye can be added to the adhesive. In this case, the first recesses are colored and become visible, resulting in excellent design. Preferred coloring components include aqueous dyes such as phthalocyanine dyes and azo-based metal complex dyes. Examples of pigments include aluminum hydroxide, kaolin, talc, calcium carbonate, titanium dioxide, clay, and zinc oxide.

When the first recess and the second recess are provided, their individual planar shapes are not limited. In particular, it is preferable to determine the first recess in consideration of design and the like. The area of each of the first recess and the second recess is not necessarily limited. There may be a plurality of recesses with different areas. However, in a long-wound toilet roll, the toilet paper has excellent wiping ability for moist skin, high absorbency, a sense of security when wiping, and a sufficient texture such as softness, fluffiness, and smoothness. Furthermore, the toilet roll has a firm hardness while the surface of the roll is comfortable to the touch. To achieve this effect, the preferred area of the first recess is 1.00 to 22.0 mm ² , more preferably 1.50 to 21.5 mm ² . The preferred area of the second recess is 0.25 to 0.75 mm ² , more preferably 0.30 to 0.50 mm ² . Furthermore, the embossing density of the first recesses and the second recesses is not necessarily limited, but as ranges in which the above-mentioned effects of the present invention are particularly easily achieved, the embossing density of the first recesses is preferably 4 to 14 embossments/cm ² , more preferably 7 to 11 embossments/cm ^2. The embossing density of the second recesses is preferably 2 to 11 embossments/cm ² , more preferably 5 to 8 embossments/cm ^2. The embossing density is a value measured by sampling a 50 cm section from the end of winding, excluding the tail seal portion.

On the other hand, in the toilet paper according to this embodiment, the depth of the first recess is 0.17 to 0.23 mm. The depth of the second recess may be shallower than the first recess, but is preferably 0.050 to 0.090 mm. When the first and second recesses have depths like this, combined with the winding diameter and winding length described above, the texture of the toilet paper and the texture of the roll surface are particularly improved and more favorable.

The depths of the first and second recesses were measured using a Keyence Corporation One-Shot 3D Measuring Macroscope VR-3200 or equivalent and image analysis software "VR-H1A" or equivalent. Measurements were performed at a magnification of 12x and a field of view of 24mm x 18mm. However, the magnification and field of view can be adjusted as needed depending on the size of the embossment (recess). The specific measurement procedure is described with reference to Figure 2. Using the software, the embossment depth (measured cross-sectional curve) profile is obtained along line segment Q1, which intersects the longest part of the periphery of one recess 40 in the image area (part X in the figure) shown from a planar perspective. From the cross-sectional curve of this embossing depth profile, surface roughness components with wavelengths shorter than λc: 800 μm (where λc is the "filter defining the boundary between the roughness component and the waviness component" described in JIS-B0601 "3.1.1.2") are removed using a low-pass filter. Of the "contour curve Q2" of the image portion (part Y in the figure) shown from a cross-sectional viewpoint, the two recess edge points P1 and P2 where the upward curvature is strongest and the minimum value sandwiched between the recess edge points P1 and P2 are determined and defined as the minimum depth value Min. Furthermore, the average value of the depth values of the recess edge points P1 and P2 is defined as the maximum depth value Max. In this way, the embossing depth = maximum value Max - minimum value Min. The distance (length) on the X-Y plane between the recess edge points P1 and P2 is defined as the length of the longest part. The two recess edge points P1 and P2 where the upward curvature is strongest are selected visually. When making this selection, the contour E in the planar image of the recess 40 being measured may be used as a reference. Similarly, the depth of the recess is measured at the shortest point in the direction perpendicular to the longest point, and the larger value is used as the depth of the recess. The above measurements are performed on any 10 embossments on the surface of the toilet paper, and the average value is used as the final embossment depth.

The area of each of the first and second recesses is also measured by visually checking the outline of the embossed recesses from the 3D image obtained using the One-Shot 3D Measuring Macroscope VR-3200 or equivalent and the image analysis software "VR-H1A" or equivalent, and measuring the area within the outline. This is done for any 10 embossments on the surface of the toilet paper, and the average value is used as the final area of the embossed recesses.

Furthermore, in the toilet paper according to this embodiment, it is desirable that the MMD of the outer laminate surface of the first sheet on which the first and second recesses are formed be 10.0 or less. Considering the feel of the recesses, a more preferable MMD value is 8.0 to 10.0. The MMD is measured using the measuring device 100 shown in Figure 3. The friction element's contact surface is brought into contact with the surface of a measurement sample, to which a tension of 20 g/cm is applied in a predetermined direction, at a contact pressure of 25 g. The friction element is then moved 2 cm in approximately the same direction as the tension at a speed of 0.1 cm/s. The friction coefficient at this time is measured using a friction feel tester KES-SE (manufactured by Kato Tech Co., Ltd.) or its equivalent. The MMD is the friction coefficient divided by the friction distance (movement distance = 2 cm). The friction element is made of 20 adjacent piano wires P with a diameter of 0.5 mm, and has a contact surface formed to have a length and width of 10 mm. The contact surface is formed with a unit bulge, the tip of which is made of 20 piano wires P (with a curvature radius of 0.25 mm).

Furthermore, in this toilet paper, it is desirable that the second sheet also have recesses formed by embossing or the like. By forming recesses on the second sheet by embossing, the difference in elongation between the second sheet and the first sheet, on which recesses and protrusions are formed, is reduced, preventing wrinkles and paper breaks during the manufacturing process. This also facilitates the production of toilet paper with a good balance between texture (e.g., softness) and thickness, making it easier to achieve the effects of the present invention. However, it is desirable that the area of the recesses on the second sheet be smaller than the first recesses on the first sheet and approximately the same as the second recesses. It is also desirable that the embossing density be higher than the second recesses on the first sheet. Specifically, the preferred area of the recesses on the second sheet is 0.25 to 0.75 mm ² , and more preferably 0.30 to 0.50 mm ² . Furthermore, the preferred embossing density of the recesses on the second sheet is 2 to 12/cm ² , more preferably 2 to 11/cm ² , and even more preferably 4 to 8/cm ² .

Furthermore, it is desirable for this toilet paper to have a softness of 1.8 to 2.7 cN/100 mm, more preferably 2.0 to 2.6 cN/100 mm. This softness is measured using the handle-o-meter method in accordance with JIS L 1096 (2010) Method E.

In the toilet paper of this embodiment, when the MMD and softness are within the above ranges, the texture and the texture of the roll surface are particularly improved and favorable.

Here, the toilet roll according to this embodiment preferably has a roll winding density of 0.74 to 1.30 m/ ^cm2 , and more preferably a roll density of 0.12 to 0.18 g/ ^cm3 .

The roll winding density is expressed as (winding length × number of plies) ÷ (cross-sectional area of the roll). The cross-sectional area of the roll is expressed as {cross-sectional area of the roll's winding diameter (outer diameter) L1} - (cross-sectional area of the cardboard tube outer diameter L3). Therefore, for example, if the winding length is 46 m, there are 2 plies, the winding diameter L1 is 115 mm, and the cardboard tube outer diameter L3 is 38 mm, the winding density = (46 m × 2) ÷ {3.14 × (115 mm ÷ 2 ÷ 10) ² - 3.14 × (38 mm ÷ 2 ÷ 10) ² } = 0.99 m/cm ² .

The roll density is expressed as (roll mass) ÷ (roll volume). The roll mass is the mass of the toilet roll per 114 mm of roll width. The roll volume is expressed as [{cross-sectional area of the roll's winding diameter (diameter) L1} - (cross-sectional area of the cardboard core outer diameter L3)] × roll width (converted per 114 mm). For example, if the roll weight (excluding the core) per 114 mm of roll width is 152 g, the winding diameter L1 = 115 mm, and the cardboard core outer diameter L3 = 38 mm, the roll density is 152 g ÷ [{3.14 × (115 mm ÷ 2 ÷ 10) ² - 3.14 × (38 mm ÷ 2 ÷ 10) ² } × (114 mm ÷ 10)] = 0.14 g/cm ³ .

Roll winding density and roll density are indicators of how tightly or loosely a toilet roll is wound. If it is too loose, the area near the paper core will be prone to excessive deformation, such as protruding, and if it is too stiff, the toilet paper will feel stiff when held in the hand.

Furthermore, in addition to the above-mentioned roll winding density and roll density, it is desirable that the toilet roll according to this embodiment also have a roll compression degree of 0.66 to 1.50.

The degree of roll compression is expressed as (cross-sectional area calculated based on paper thickness) / (cross-sectional area of the roll). The calculation method for (cross-sectional area of the roll) is the same as for (cross-sectional area of the roll) in the roll winding density above. Furthermore, (cross-sectional area calculated based on paper thickness) is a value calculated by (paper thickness) x (winding length). This value of (cross-sectional area calculated based on paper thickness) does not take into account the gaps that form when the toilet paper is wound around the paper core. On the other hand, the value of (cross-sectional area of the roll) does take into account the gaps that form when the toilet paper is wound around the paper core. Therefore, the degree of roll compression, expressed as the ratio of (cross-sectional area calculated based on paper thickness) to (cross-sectional area of the roll), is also an indicator of how tightly or loosely the toilet roll is wound. As mentioned above, if it is too loose, it will be prone to excessive deformation, such as the area near the paper core protruding, and if it is too stiff, the toilet roll will feel stiff when held in the hand. Furthermore, roll winding density is easily affected by the number of plies, and roll compression is easily affected by paper thickness.

The above roll density and roll winding density further improve and enhance the texture of the roll surface, especially when combined with the texture due to the toilet paper's structure.

On the other hand, it is desirable that the toilet paper according to this embodiment contains 55% or more by mass of the fibers constituting the paper, preferably 60% to 70% by mass, of hardwood-derived pulp. Hardwood-derived pulp has short fiber length, which tends to improve the texture of the paper surface. The toilet roll according to this embodiment tends to feel stiff when wound long, but by using 55% or more by mass of hardwood-derived pulp, the paper becomes smoother and less stiff. The texture during use is also improved. Known hardwood-derived pulp includes LBKP (hardwood kraft pulp), LUKP, and LOKP, but bleached LBKP is preferable. As for fibers other than hardwood-derived pulp, softwood pulp is preferable. In this case, chlorine-bleached softwood kraft pulp (NBKP) is preferable.

The toilet paper according to this embodiment preferably contains or is acted upon by a temporary wet strength agent and a dry strength agent. The dry strength agent increases the dry tensile strength, making it easier to achieve sufficient strength and perforation strength during use. Furthermore, when winding a paper tube to a longer length, the paper is less likely to break even if the winding tension during manufacturing is increased. Furthermore, increased dry tensile strength also increases water absorption. On the other hand, increasing dry tensile strength using only a dry strength agent reduces water disintegrability and makes the paper hard, which can lead to poor texture and usability. A temporary wet strength agent does not disintegrate in water upon short-term contact with moisture during wiping, and has sufficient water disintegrability against the amount of moisture that accumulates in the trap in a water-based toilet, while slightly reducing paper strength compared to when only a dry strength agent is used, improving texture. Therefore, by including a temporary wet strength agent in addition to a dry strength agent, the toilet paper has a better texture, is particularly strong enough to wipe away moisture from skin after using a shower toilet, has high moisture absorption properties that give a sense of security, and is more likely to prevent moisture from seeping into the hands.

The amount of temporary wet strength agent is not necessarily limited, but is preferably 0.01 to 0.04% by mass. It is preferable to add this temporary wet strength agent during manufacturing. The type of temporary wet strength agent is not necessarily limited, but examples include polyacrylamide resin, polyamidepolyamine epichlorohydrin resin, urea resin, acid colloid/melamine resin, thermally crosslinkable coating PAM, Seiko PMC Corporation's TS-20 and TS4070, polymeric aldehyde-functional compounds such as glyoxylated polyacrylamide and cationic glyoxylated polyacrylamide, copolymers of acrylamide monomers modified with divalent aldehydes such as glyoxal and other copolymerizable unsaturated monomers, and dialdehyde starch.

The amount of dry strength agent is not necessarily limited, but is preferably 0.005 to 0.15% by mass. This dry strength agent is preferably added internally. The type of dry strength agent is not necessarily limited, but examples include polyacrylamide, CMC (carboxymethyl cellulose) or its salts such as sodium carboxymethyl cellulose, calcium carboxymethyl cellulose, and zinc carboxymethyl cellulose. However, starch and cationized starch are not desirable because they tend to make the surface of the toilet paper feel crisp and hard.

A particularly preferred dry strength agent is an enzyme-based strength agent. The toilet paper in the toilet roll of this embodiment is particularly suitable for containing this enzyme-based strength agent. Unlike starch and other strength agents, which act like adhesives to add strength, enzyme-based strength agents contain enzymes that decompose polysaccharides, fibrillating fibers and fluffing the surface and interior of the fibers. Therefore, the action of the enzyme-based strength agent does not inhibit hydrogen bonding, increasing the proportion of cellulose fibers alone, which, combined with the entanglement of fibers, particularly on the surface, increases paper strength. Furthermore, while enzyme-based strength agents increase paper strength in this way, they do not inhibit hydrolysis. This improves the texture of the toilet paper, resulting in an excellent roll surface texture and excellent water absorbency, especially when the roll length is long and the roll density and roll winding density are high. The presence of the enzyme-based strength agent in the toilet paper can be confirmed using high-performance liquid chromatography (HPLC) or mass spectrometry (LC/MS) to determine whether the enzyme-based strength agent is acting on the fibers.

Here, examples of enzyme-based paper strength agents according to the present invention include those containing at least one of cellulase, hemicellulase, and xylanase. Examples of paper strength agents containing such enzymes include Hercobond 8922 (manufactured by Riken Green Co., Ltd.), Hercobond EZ4423 (manufactured by Riken Green Co., Ltd.), "Celluleucin T2" manufactured by HPI Corporation, "Meicelase (registered trademark)" manufactured by Meiji Seika Pharma, "Novozyme (registered trademark) 188" and "Celluclast" manufactured by Novozymes, and "Multifect CX10L, B, GCc, GC, Pectinase (hemicellulase)," "Spezyme CP," and "GC220" manufactured by Genencor. The amount added is not limited, but a range of 0.5 to 2.0 kg/t is desirable.

The dry tensile strength of the toilet paper according to this embodiment is not limited, but is preferably 400 cN/25 mm to 600 cN/25 mm, preferably 450 cN/25 mm to 580 cN/25 mm, in the machine direction, and 100 cN/25 mm to 200 cN/25 mm, preferably 135 cN/25 mm to 180 cN/25 mm, in the cross direction. Here, the machine direction of the paper, also known as the MD direction, is the direction in which the paper flows during papermaking. The cross direction of the paper, also known as the CD direction, is the direction perpendicular to the machine direction (MD direction) during papermaking. The dry tensile strength according to this embodiment is a value measured in accordance with JIS P 8113 (2006) and is measured as follows. Test specimens cut to approximately 25 mm (±0.5 mm) wide x 150 mm long in both the machine and cross directions are used. Test pieces are measured in multi-ply form. The test machine used is a Minebea Co., Ltd. load cell tensile tester TG-200N or an equivalent machine. The grip spacing is set to 100 mm and the tensile speed to 100 mm/min. Measurements are performed by clamping both ends of the test piece into the grips of the test machine, applying a tensile load to the paper piece in the vertical direction, and reading the indicated value (digital value) when the paper breaks. Five sets of samples are prepared in both the vertical and horizontal directions, and measurements are taken five times in each direction. The average of these measurements is taken as the dry tensile strength in each direction.

The wet tensile strength of the toilet paper according to this embodiment in the longitudinal direction is 20 cN/25 mm or more and 60 cN/25 mm or less, preferably 30 cN/25 mm or more and 55 cN/25 mm or less, and the wet tensile strength in the transverse direction is desirably 10 cN/25 mm or more and 30 cN/25 mm or less. Wet tensile strength is measured based on JIS P 8135 (1998) and is measured as follows. Test specimens are cut to approximately 25 mm (±0.5 mm) wide x 150 mm long in both the longitudinal and transverse directions. Multi-ply toilet paper is measured as multi-ply. The test machine used is a Minebea Co., Ltd. load cell tensile tester TG-200N or an equivalent machine. The grip spacing is set to 100 mm, and the tensile speed is set to 50 mm/min. The test specimens are cured in a dryer at 105°C for 10 minutes. After clamping both ends of the test piece into the grips of the testing machine, a water-soaked flat brush is used to apply water horizontally to the center of the test piece over a width of approximately 10 mm. Immediately afterwards, a tensile load is applied to the paper in the vertical direction, and the reading (digital value) is read when the paper breaks. Five sets of samples are prepared in both the vertical and horizontal directions, and measurements are taken five times in each direction, with the average of these measurements being taken as the wet tensile strength in each direction.

On the other hand, the toilet paper of this embodiment should have a water-disintegration time of 60 seconds or less, preferably 20 seconds or more and 45 seconds or less. Water-disintegration time of 60 seconds or less reduces the risk of clogging pipes when disposed of in a flush toilet or similar. Furthermore, a time of 20 seconds or more reduces the risk of the fibers immediately unraveling and tearing when wiping away a large amount of water after using a shower toilet. This water-disintegration time (ease of unraveling) is measured in accordance with JIS P 4501 (1993). To test for ease of unraveling, a 300 mL beaker containing 300 mL of water (water temperature 20±5°C) is placed on a magnetic stirrer, and the rotor speed is adjusted to 600±10 rpm. A test specimen measuring 100±2 mm square is placed in the beaker, and a stopwatch is started. The rotor speed initially drops to approximately 500 rpm due to the resistance of the test specimen, and then increases as the test specimen unravels. The stopwatch is stopped when the rotation speed recovers to 540 rotations, and the time is measured in 1-second increments. The test is performed five times and the result of the ease of unraveling is expressed as the average. The rotor is a disk with a diameter of 35 mm and a thickness of 12 mm.

On the other hand, it is desirable for the toilet paper according to this embodiment to have a penetration count of 9 or more sheets. To measure the penetration count, stack multiple sheets of toilet paper under their own weight, drip 100 μL of water from 10 mm above the topmost sheet of toilet paper, and immediately check for penetration into the bottom layer. Start with a small number of layers and increase the number of layers until penetration is no longer noticeable, and measure the maximum number of layers at which penetration can be confirmed. If the number exceeds 9 sheets, it can be said that water penetrates extremely quickly.

Furthermore, the toilet paper according to this embodiment preferably has perforations arranged at predetermined intervals along the length. The perforation spacing is not limited, but can be 100 to 120 mm. The perforation strength is preferably 580 to 700 cN/114 mm. The perforation strength is measured in accordance with the dry tensile strength measurement method based on JIS P 8113 (2006). The measurement sample is 200 mm long and the full width of the toilet paper product, with the perforation centered along the length. The measurement is performed by folding the sample in half or quarters along the length (corresponding to the MD axis) to a width that can be clamped by the chuck of the tensile tester, with a grip distance of 100 mm and a tensile speed of 100 mm/min. This measurement is performed five times, converted to a width of 114 mm, and the average value is taken as the perforation strength.

The testing machine used may be a Minebea Co., Ltd. load cell tensile testing machine TG-200N or an equivalent machine.

Furthermore, the physical properties and composition of the toilet rolls in Examples and Comparative Examples of the present invention, such as water disintegrability and number of sheets per sheet, were measured. Furthermore, sensory evaluation tests were conducted on the following items: "Roll firmness (roll hardness)," "Roll surface feel," "Daily roll replacement frequency," "Toilet paper thickness (feeling of security during use)," "Toilet paper softness," "Toilet paper fluffiness," "Toilet paper smoothness," and "Toilet paper wiping feel." This sensory evaluation test involved 20 subjects actually using the toilet rolls and evaluating each item. The evaluation also used Comparative Example 1, a conventional two-ply product, as the reference sample. The evaluation was conducted on a seven-point scale, with the reference sample receiving 4 points, and compared against each other, with 7 points representing exceptionally good, 6 points representing good, 5 points representing somewhat good, and 3 points representing somewhat poor. 2 points representing poor, and 1 point representing particularly poor, and the average score was calculated. Regarding "roll firmness (roll hardness)," samples that were harder than the reference sample were given a higher score, and samples that were softer were given a lower score.

In the examples and comparative examples, toilet paper was used that was made into two plies by laminating a first sheet and a second sheet, each having a first recess and a second recess on the same surface, with the first recess and second recess formed on the outer surface. The second sheet had a recess formed therein with the same shape and depth as the second recess of the first sheet. The shapes of the first recess and second recess in Examples 1 to 7, Comparative Example 1, and Comparative Examples 4 to 7 were the same, and the shapes of the first recess and second recess in Comparative Example 2 and Comparative Example 3 were the same.
A paper strength agent was used in each example. In Examples 1 to 7 and Comparative Examples 4 to 7, an enzyme-based paper strength agent (Hercobond 8922, manufactured by Riken Green Co., Ltd.) was used as the dry paper strength agent. Also, a temporary paper strength agent (TS4070, manufactured by Seiko PMC Co., Ltd.) was used. In Comparative Example 1, a cationized starch (DD4280, manufactured by Seiko PMC Co., Ltd.) was used as the dry paper strength agent. Also, a temporary paper strength agent (TS4070, manufactured by Seiko PMC Co., Ltd.) was used.
Other physical properties and compositions of the examples and comparative examples are shown in Table 1. The measurement methods are as described above.

As the results shown in Table 1 show, the "firmness of the roll (hardness of the roll)" tends to increase as the winding length increases. The examples according to the present invention have a longer winding length than comparative examples 1 to 3, and are rated as having firmer rolls and harder rolls. However, despite this, the feel of the roll surface is rated higher than comparative examples 1 to 3.

Furthermore, in all categories related to the texture of the toilet paper, including "thickness of the toilet paper (sense of security when using)," "softness of the toilet paper," "fluffiness of the toilet paper," "smoothness of the toilet paper," and "wiping feel of the toilet paper," the results were superior to those of Comparative Examples 1 to 3, which were wound short and loosely.

Furthermore, looking at Comparative Examples 4 to 7, it appears that the ratings tend to be slightly lower than those of Examples 1 to 7 according to the present invention.

In other words, the examples of the present invention provide toilet paper that is excellent in wiping away moisture from skin, has high absorbency, and provides a sense of security when wiping, while also providing a satisfactory texture that is soft, fluffy, and smooth.Furthermore, the roll is firm yet has an excellent feel to the touch on the surface.

1...toilet roll, 10...toilet paper, 20...paper tube (tube core), L1...toilet roll winding diameter (diameter), L3...toilet roll tube core diameter, L2...toilet roll width.

The present invention relates to toilet rolls.

As flushing toilets become more common, there is a growing demand for toilet paper that is suitable for use in flushing toilets.

In toilets with flushing functions, the defecation and urination areas are washed with warm or cold water, so it is necessary to wipe off the feces and urine along with any moisture that has adhered to the skin during the flushing process.

Therefore, toilet paper is required to be able to wipe away moisture from skin, be highly absorbent, and provide a sense of security when wiping. Laminate embossing is known as a technique for improving the ability to wipe away moisture from skin. Laminate embossing is a technique in which embossed plies are laminated together using adhesive, which increases strength, thickness, and water penetration resistance.

On the other hand, toilet paper is generally sold commercially in the form of toilet rolls wound around paper tubes. In recent years, toilet rolls have become longer, with the length of toilet paper wound around the paper tubes increasing.

Patent No. 6021532 JP 2019-10366 A

However, toilet paper made with laminated embossing technology is too thick and is not suitable for long rolls as is.

On the other hand, reducing the basis weight of each ply to increase the length of the paper can reduce the softness, fluffiness, and smoothness of the texture. In particular, reducing the basis weight of toilet paper made using laminate embossing technology can make it more likely to feel crisp and stiff due to the adhesive.

Furthermore, when used as toilet rolls, the surface of the roll feels unpleasant to the touch, and users are more likely to perceive it as being harder.

The main objective of the present invention is to provide a toilet roll that has excellent wiping ability on moist skin, high absorbency, and a sense of security when wiping, and that is also suitable for long lengths of toilet paper with a soft, fluffy, and smooth texture, and that has a firmness to the roll that makes it clear that it is a long length, while also having an excellent feel to the touch on the roll surface.

The first solution to the above problem is
A toilet roll in which two plies of toilet paper are wound around a paper tube, with at least a portion of the two sheets being bonded together via embossed recesses,
The winding diameter is 120 mm or less, and the winding length is 34.5 to 55 m,
The toilet paper has a basis weight per ply of 13.0 or more and less than 16.0 g/m ² , and a thickness of 175 to 238 μm for two plies;
The toilet paper,
A first sheet having recesses formed by embossing and a second sheet,
The embossing density of the recesses in the first sheet is 2 to 14/ ^cm² ,
The toilet paper is wound around the paper tube with the first sheet facing outward.
This toilet roll is characterized by the following:

The second method is
In the toilet roll according to the first aspect, the second sheet has recesses formed by embossing, and the recesses are shallower in depth than the first recesses formed in the first sheet.

The third method is
The toilet roll according to the first or second means has a roll winding density of 0.74 to 1.30 m/ ^cm² and a roll density of 0.12 to 0.18 g/ ^cm³ .

The fourth method is
The toilet roll according to any one of the first to third aspects has a roll compression degree of 0.66 to 1.50.

The fifth method is
The toilet paper is a toilet roll according to the first to fourth means, which is treated with an enzyme-based paper strength agent.

The sixth method is
The toilet paper is a toilet roll according to any one of the first to fifth means, which does not contain starch or cationic starch.

The present invention provides a toilet roll that has excellent wiping ability on moist skin, high absorbency, and a sense of security when wiping, and that is suitable for long lengths of toilet paper with a soft, fluffy, and smooth texture.The roll has a firmness that makes it clear that it is a long length, and the surface of the roll has an excellent feel to the touch.

1 is a perspective view of a toilet roll according to an embodiment of the present invention. FIG. FIG. 4 is a schematic diagram for explaining the procedure for measuring the embossing depth according to the present invention. FIG. 1 is a schematic diagram for explaining a method for measuring MMD according to the present invention.

Next, an embodiment of the present invention will be described in detail below with reference to the drawings.

As shown in Figure 1, the toilet roll according to this embodiment is a cylindrically shaped toilet paper roll in which two plies of water-disintegrable toilet paper 10, consisting of a first sheet and a second sheet, are wound around a paper tube (also called a tube core) 20. Note that water-disintegrability here refers to a disintegration rate of 100 seconds or less according to JIS P 4501.

While conventional two-ply toilet rolls have a roll length of around 20 to 25 m, the toilet roll according to this embodiment has a roll length of 34.5 to 55 m, preferably 38 to 50 m, and is sometimes referred to as a long product or a 1.5 to 2 times roll product.

On the other hand, the roll diameter L1 (diameter) of the toilet roll of this embodiment is 120 mm or less, preferably 107 to 119 mm. JIS P 4501 stipulates that the roll diameter L1 of a toilet roll must be 120 mm or less, and general holders for holding toilet rolls are manufactured based on this 120 mm standard. The toilet roll of this embodiment has a roll diameter of 120 mm or less and can be set in a general holder. Here, the roll diameter L1 is a value measured using a diameter ruler manufactured by Muratec KDS Corporation or an equivalent device. The measured value is the average value of measurements taken at three different locations in the width direction. Note that the average value for products from the same production lot is the average value of five rolls. Note that the roll width L2 of the toilet roll of this embodiment is not limited, but is preferably 100 to 130 mm. The outer diameter L3 of the cardboard core is also not limited, but is 34 to 42 mm.

Here, the impression of hardness when holding a toilet roll in the hand is influenced not only by whether the roll is dense or not, but also by the collapse of the recesses caused by embossing when the toilet paper is stretched and wound, as well as the physical properties and surface characteristics of the toilet paper. Therefore, the toilet roll according to this embodiment is a two-ply toilet paper with recesses caused by embossing. This toilet paper has a basis weight per ply of preferably 13.0 to 17.0 g/m ² , more preferably 13.5 to 16.0 g/m ² , and a thickness of the two plies of preferably 175 to 238 μm , more preferably 180 to 225 μm . Within these basis weight and thickness ranges, wiping performance on moist skin, high absorbency, and a sense of security when wiping can be sufficiently improved, and the feel of the roll surface against the skin can be improved when the winding length is increased.

The basis weight (grammage) is measured in accordance with JIS P 8124. Paper thickness is measured by first conditioning the test specimen thoroughly (usually for approximately 8 hours) under the conditions specified in JIS P 8111 (1998), and then measuring the two-ply specimen under the same conditions using a PEACOCK H-type dial thickness gauge (thickness measuring device) (manufactured by Ozaki Seisakusho). Specifically, after ensuring there is no dust or dirt between the plunger and the measuring table, the plunger is lowered onto the measuring table, the dial thickness gauge's scale is adjusted to zero, the plunger is then raised, the sample is placed on the testing table, and the plunger is opened to 700 μm. The lever is then lowered in one go, and the gauge reading is taken. During measurement, the plunger is simply placed on the test table, not pressed down. The 10 mm diameter circular flat surface of the plunger terminal is positioned perpendicular to the paper surface, and the load during paper thickness measurement is approximately 70 gf. The paper thickness is the average value obtained by measuring 10 times.

Furthermore, the first sheet in the toilet paper according to this embodiment has first and second recesses of different depths formed by embossing. The first and second recesses of this first sheet are both formed on the same surface, and the other surface preferably has convex portions corresponding to the first and second recesses. The first sheet is wound around the paper tube so that it faces outward. It is particularly preferable for the recessed surface to be on the outer surface.

Furthermore, this toilet paper may be two-ply, with the inner layer side of the first recess of the first sheet bonded to the inner layer side of the second sheet. The first sheet may be bonded to the inner layer side of the second sheet via an adhesive applied to the convex portions corresponding to the concave portions of the first sheet. Alternatively, the first sheet may be integrated by pressure bonding using an embossing process known as single embossing. Regardless of whether an adhesive is used or whether single embossing is used, when the first sheet and the second sheet are integrated,
Convex portions corresponding to only the first recesses of the first sheet or to both the first recesses and the second recesses may be formed on the outer surface of the second sheet. On the other hand, the inner laminate surface side of the second recesses is preferably not bonded to the second sheet with an adhesive. Although it is not necessary for the inner laminate surface side of all the first recesses to be bonded to the second sheet, it is desirable for all recesses to be bonded from the viewpoint of ply peeling.

When using an adhesive, either a water-based or oil-based adhesive may be used. However, preferred adhesives are water-soluble adhesives such as PVA (polyvinyl alcohol) and CMC (carboxymethyl cellulose). CMC, a cellulose-based water-soluble adhesive, is particularly desirable.

The adhesive itself can be an ink with adhesive properties, or a coloring component such as a pigment or dye can be added to the adhesive. In this case, the first recesses are colored and become visible, resulting in excellent design. Preferred coloring components include aqueous dyes such as phthalocyanine dyes and azo-based metal complex dyes. Examples of pigments include aluminum hydroxide, kaolin, talc, calcium carbonate, titanium dioxide, clay, and zinc oxide.

When the first recess and the second recess are provided, their individual planar shapes are not limited. In particular, it is preferable to determine the first recess in consideration of design and the like. The area of each of the first recess and the second recess is not necessarily limited. There may be a plurality of recesses with different areas. However, in a long-wound toilet roll, the toilet paper has excellent wiping ability for moist skin, high absorbency, a sense of security when wiping, and a sufficient texture such as softness, fluffiness, and smoothness. Furthermore, the toilet roll has a firm hardness while the surface of the roll is comfortable to the touch. To achieve this effect, the preferred area of the first recess is 1.00 to 22.0 mm ² , more preferably 1.50 to 21.5 mm ² . The preferred area of the second recess is 0.25 to 0.75 mm ² , more preferably 0.30 to 0.50 mm ² . Furthermore, the embossing density of the first recesses and the second recesses is not necessarily limited, but as ranges in which the above-mentioned effects of the present invention are particularly easily achieved, the embossing density of the first recesses is preferably 4 to 14 embossments/cm ² , more preferably 7 to 11 embossments/cm ^2. The embossing density of the second recesses is preferably 2 to 11 embossments/cm ² , more preferably 5 to 8 embossments/cm ^2. The embossing density is a value measured by sampling a 50 cm section from the end of winding, excluding the tail seal portion.

On the other hand, in the toilet paper according to this embodiment, the depth of the first recess is 0.17 to 0.23 mm. The depth of the second recess may be shallower than the first recess, but is preferably 0.050 to 0.090 mm. When the first and second recesses have depths like this, combined with the winding diameter and winding length described above, the texture of the toilet paper and the texture of the roll surface are particularly improved and more favorable.

The depths of the first and second recesses were measured using a Keyence Corporation One-Shot 3D Measuring Macroscope VR-3200 or equivalent and image analysis software "VR-H1A" or equivalent. Measurements were performed at a magnification of 12x and a field of view of 24mm x 18mm. However, the magnification and field of view can be adjusted as needed depending on the size of the embossment (recess). The specific measurement procedure is described with reference to Figure 2. Using the software, the embossment depth (measured cross-sectional curve) profile is obtained along line segment Q1, which intersects the longest part of the periphery of one recess 40 in the image area (part X in the figure) shown from a planar perspective. From the cross-sectional curve of this embossing depth profile, surface roughness components with wavelengths shorter than λc: 800 μm (where λc is the "filter defining the boundary between the roughness component and the waviness component" described in JIS-B0601 "3.1.1.2") are removed using a low-pass filter. Of the "contour curve Q2" of the image portion (part Y in the figure) shown from a cross-sectional viewpoint, the two recess edge points P1 and P2 where the upward curvature is strongest and the minimum value sandwiched between the recess edge points P1 and P2 are determined and defined as the minimum depth value Min. Furthermore, the average value of the depth values of the recess edge points P1 and P2 is defined as the maximum depth value Max. In this way, the embossing depth = maximum value Max - minimum value Min. The distance (length) on the X-Y plane between the recess edge points P1 and P2 is defined as the length of the longest part. The two recess edge points P1 and P2 where the upward curvature is strongest are selected visually. When making this selection, the contour E in the planar image of the recess 40 being measured may be used as a reference. Similarly, the depth of the recess is measured at the shortest point in the direction perpendicular to the longest point, and the larger value is used as the depth of the recess. The above measurements are performed on any 10 embossments on the surface of the toilet paper, and the average value is used as the final embossment depth.

The area of each of the first and second recesses is also measured by visually checking the outline of the embossed recesses from the 3D image obtained using the One-Shot 3D Measuring Macroscope VR-3200 or equivalent and the image analysis software "VR-H1A" or equivalent, and measuring the area within the outline. This is done for any 10 embossments on the surface of the toilet paper, and the average value is used as the final area of the embossed recesses.

Furthermore, in the toilet paper according to this embodiment, it is desirable that the MMD of the outer laminate surface of the first sheet on which the first and second recesses are formed be 10.0 or less. Considering the feel of the recesses, a more preferable MMD value is 8.0 to 10.0. The MMD is measured using the measuring device 100 shown in Figure 3. The friction element's contact surface is brought into contact with the surface of a measurement sample, to which a tension of 20 g/cm is applied in a predetermined direction, at a contact pressure of 25 g. The friction element is then moved 2 cm in approximately the same direction as the tension at a speed of 0.1 cm/s. The friction coefficient at this time is measured using a friction feel tester KES-SE (manufactured by Kato Tech Co., Ltd.) or its equivalent. The MMD is the friction coefficient divided by the friction distance (movement distance = 2 cm). The friction element is made of 20 adjacent piano wires P with a diameter of 0.5 mm, and has a contact surface formed to have a length and width of 10 mm. The contact surface is formed with a unit bulge, the tip of which is made of 20 piano wires P (with a curvature radius of 0.25 mm).

Furthermore, in this toilet paper, it is desirable that the second sheet also have recesses formed by embossing or the like. By forming recesses on the second sheet by embossing, the difference in elongation between the second sheet and the first sheet, on which recesses and protrusions are formed, is reduced, preventing wrinkles and paper breaks during the manufacturing process. This also facilitates the production of toilet paper with a good balance between texture (e.g., softness) and thickness, making it easier to achieve the effects of the present invention. However, it is desirable that the area of the recesses on the second sheet be smaller than the first recesses on the first sheet and approximately the same as the second recesses. It is also desirable that the embossing density be higher than the second recesses on the first sheet. Specifically, the preferred area of the recesses on the second sheet is 0.25 to 0.75 mm ² , and more preferably 0.30 to 0.50 mm ² . Furthermore, the preferred embossing density of the recesses on the second sheet is 2 to 12/cm ² , more preferably 2 to 11/cm ² , and even more preferably 4 to 8/cm ² .

Furthermore, it is desirable for this toilet paper to have a softness of 1.8 to 2.7 cN/100 mm, more preferably 2.0 to 2.6 cN/100 mm. This softness is measured using the handle-o-meter method in accordance with JIS L 1096 (2010) Method E.

In the toilet paper of this embodiment, when the MMD and softness are within the above ranges, the texture and the texture of the roll surface are particularly improved and favorable.

Here, the toilet roll according to this embodiment preferably has a roll winding density of 0.74 to 1.30 m/ ^cm2 , and more preferably a roll density of 0.12 to 0.18 g/ ^cm3 .

The roll winding density is expressed as (winding length × number of plies) ÷ (cross-sectional area of the roll). The cross-sectional area of the roll is expressed as {cross-sectional area of the roll's winding diameter (outer diameter) L1} - (cross-sectional area of the cardboard tube outer diameter L3). Therefore, for example, if the winding length is 46 m, there are 2 plies, the winding diameter L1 is 115 mm, and the cardboard tube outer diameter L3 is 38 mm, the winding density = (46 m × 2) ÷ {3.14 × (115 mm ÷ 2 ÷ 10) ² - 3.14 × (38 mm ÷ 2 ÷ 10) ² } = 0.99 m/cm ² .

The roll density is expressed as (roll mass) ÷ (roll volume). The roll mass is the mass of the toilet roll per 114 mm of roll width. The roll volume is expressed as [{cross-sectional area of the roll's winding diameter (diameter) L1} - (cross-sectional area of the cardboard core outer diameter L3)] × roll width (converted per 114 mm). For example, if the roll weight (excluding the core) per 114 mm of roll width is 152 g, the winding diameter L1 = 115 mm, and the cardboard core outer diameter L3 = 38 mm, the roll density is 152 g ÷ [{3.14 × (115 mm ÷ 2 ÷ 10) ² - 3.14 × (38 mm ÷ 2 ÷ 10) ² } × (114 mm ÷ 10)] = 0.14 g/cm ³ .

Roll winding density and roll density are indicators of how tightly or loosely a toilet roll is wound. If it is too loose, the area near the paper core will be prone to excessive deformation, such as protruding, and if it is too stiff, the toilet paper will feel stiff when held in the hand.

Furthermore, in addition to the above-mentioned roll winding density and roll density, it is desirable that the toilet roll according to this embodiment also have a roll compression degree of 0.66 to 1.50.

The degree of roll compression is expressed as (cross-sectional area calculated based on paper thickness) / (cross-sectional area of the roll). The calculation method for (cross-sectional area of the roll) is the same as for (cross-sectional area of the roll) in the roll winding density above. Furthermore, (cross-sectional area calculated based on paper thickness) is a value calculated by (paper thickness) x (winding length). This value of (cross-sectional area calculated based on paper thickness) does not take into account the gaps that form when the toilet paper is wound around the paper core. On the other hand, the value of (cross-sectional area of the roll) does take into account the gaps that form when the toilet paper is wound around the paper core. Therefore, the degree of roll compression, expressed as the ratio of (cross-sectional area calculated based on paper thickness) to (cross-sectional area of the roll), is also an indicator of how tightly or loosely the toilet roll is wound. As mentioned above, if it is too loose, it will be prone to excessive deformation, such as the area near the paper core protruding, and if it is too stiff, the toilet roll will feel stiff when held in the hand. Furthermore, roll winding density is easily affected by the number of plies, and roll compression is easily affected by paper thickness.

The above roll density and roll winding density further improve and enhance the texture of the roll surface, especially when combined with the texture due to the toilet paper's structure.

On the other hand, it is desirable that the toilet paper according to this embodiment contains 55% or more by mass of the fibers constituting the paper, preferably 60% to 70% by mass, of hardwood-derived pulp. Hardwood-derived pulp has short fiber length, which tends to improve the texture of the paper surface. The toilet roll according to this embodiment tends to feel stiff when wound long, but by using 55% or more by mass of hardwood-derived pulp, the paper becomes smoother and less stiff. The texture during use is also improved. Known hardwood-derived pulp includes LBKP (hardwood kraft pulp), LUKP, and LOKP, but bleached LBKP is preferable. As for fibers other than hardwood-derived pulp, softwood pulp is preferable. In this case, chlorine-bleached softwood kraft pulp (NBKP) is preferable.

The toilet paper according to this embodiment preferably contains or is acted upon by a temporary wet strength agent and a dry strength agent. The dry strength agent increases the dry tensile strength, making it easier to achieve sufficient strength and perforation strength during use. Furthermore, when winding a paper tube to a longer length, the paper is less likely to break even if the winding tension during manufacturing is increased. Furthermore, increased dry tensile strength also increases water absorption. On the other hand, increasing dry tensile strength using only a dry strength agent reduces water disintegrability and makes the paper hard, which can lead to poor texture and usability. A temporary wet strength agent does not disintegrate in water upon short-term contact with moisture during wiping, and has sufficient water disintegrability against the amount of moisture that accumulates in the trap in a water-based toilet, while slightly reducing paper strength compared to when only a dry strength agent is used, improving texture. Therefore, by including a temporary wet strength agent in addition to a dry strength agent, the toilet paper has a better texture, is particularly strong enough to wipe away moisture from skin after using a shower toilet, has high moisture absorption properties that give a sense of security, and is more likely to prevent moisture from seeping into the hands.

The amount of temporary wet strength agent is not necessarily limited, but is preferably 0.01 to 0.04% by mass. It is preferable to add this temporary wet strength agent during manufacturing. The type of temporary wet strength agent is not necessarily limited, but examples include polyacrylamide resin, polyamidepolyamine epichlorohydrin resin, urea resin, acid colloid/melamine resin, thermally crosslinkable coating PAM, Seiko PMC Corporation's TS-20 and TS4070, polymeric aldehyde-functional compounds such as glyoxylated polyacrylamide and cationic glyoxylated polyacrylamide, copolymers of acrylamide monomers modified with divalent aldehydes such as glyoxal and other copolymerizable unsaturated monomers, and dialdehyde starch.

The amount of dry strength agent is not necessarily limited, but is preferably 0.005 to 0.15% by mass. This dry strength agent is preferably added internally. The type of dry strength agent is not necessarily limited, but examples include polyacrylamide, CMC (carboxymethyl cellulose) or its salts such as sodium carboxymethyl cellulose, calcium carboxymethyl cellulose, and zinc carboxymethyl cellulose. However, starch and cationized starch are not desirable because they tend to make the surface of the toilet paper feel crisp and hard.

A particularly preferred dry strength agent is an enzyme-based strength agent. The toilet paper in the toilet roll of this embodiment is particularly suitable for containing this enzyme-based strength agent. Unlike starch and other strength agents, which act like adhesives to add strength, enzyme-based strength agents contain enzymes that decompose polysaccharides, fibrillating fibers and fluffing the surface and interior of the fibers. Therefore, the action of the enzyme-based strength agent does not inhibit hydrogen bonding, increasing the proportion of cellulose fibers alone, which, combined with the entanglement of fibers, particularly on the surface, increases paper strength. Furthermore, while enzyme-based strength agents increase paper strength in this way, they do not inhibit hydrolysis. This improves the texture of the toilet paper, resulting in an excellent roll surface texture and excellent water absorbency, especially when the roll length is long and the roll density and roll winding density are high. The presence of the enzyme-based strength agent in the toilet paper can be confirmed using high-performance liquid chromatography (HPLC) or mass spectrometry (LC/MS) to determine whether the enzyme-based strength agent is acting on the fibers.

Here, examples of enzyme-based paper strength agents according to the present invention include those containing at least one of cellulase, hemicellulase, and xylanase. Examples of paper strength agents containing such enzymes include Hercobond 8922 (manufactured by Riken Green Co., Ltd.), Hercobond EZ4423 (manufactured by Riken Green Co., Ltd.), "Celluleucin T2" manufactured by HPI Corporation, "Meicelase (registered trademark)" manufactured by Meiji Seika Pharma, "Novozyme (registered trademark) 188" and "Celluclast" manufactured by Novozymes, and "Multifect CX10L, B, GCc, GC, Pectinase (hemicellulase)," "Spezyme CP," and "GC220" manufactured by Genencor. The amount added is not limited, but a range of 0.5 to 2.0 kg/t is desirable.

The dry tensile strength of the toilet paper according to this embodiment is not limited, but is preferably 400 cN/25 mm to 600 cN/25 mm, preferably 450 cN/25 mm to 580 cN/25 mm, in the machine direction, and 100 cN/25 mm to 200 cN/25 mm, preferably 135 cN/25 mm to 180 cN/25 mm, in the cross direction. Here, the machine direction of the paper, also known as the MD direction, is the direction in which the paper flows during papermaking. The cross direction of the paper, also known as the CD direction, is the direction perpendicular to the machine direction (MD direction) during papermaking. The dry tensile strength according to this embodiment is a value measured in accordance with JIS P 8113 (2006) and is measured as follows. Test specimens cut to approximately 25 mm (±0.5 mm) wide x 150 mm long in both the machine and cross directions are used. Test pieces are measured in multi-ply form. The test machine used is a Minebea Co., Ltd. load cell tensile tester TG-200N or an equivalent machine. The grip spacing is set to 100 mm and the tensile speed to 100 mm/min. Measurements are performed by clamping both ends of the test piece into the grips of the test machine, applying a tensile load to the paper piece in the vertical direction, and reading the indicated value (digital value) when the paper breaks. Five sets of samples are prepared in both the vertical and horizontal directions, and measurements are taken five times in each direction. The average of these measurements is taken as the dry tensile strength in each direction.

The wet tensile strength of the toilet paper according to this embodiment in the longitudinal direction is 20 cN/25 mm or more and 60 cN/25 mm or less, preferably 30 cN/25 mm or more and 55 cN/25 mm or less, and the wet tensile strength in the transverse direction is desirably 10 cN/25 mm or more and 30 cN/25 mm or less. Wet tensile strength is measured based on JIS P 8135 (1998) and is measured as follows. Test specimens are cut to approximately 25 mm (±0.5 mm) wide x 150 mm long in both the longitudinal and transverse directions. Multi-ply toilet paper is measured as multi-ply. The test machine used is a Minebea Co., Ltd. load cell tensile tester TG-200N or an equivalent machine. The grip spacing is set to 100 mm, and the tensile speed is set to 50 mm/min. The test specimens are cured in a dryer at 105°C for 10 minutes. After clamping both ends of the test piece into the grips of the testing machine, a water-soaked flat brush is used to apply water horizontally to the center of the test piece over a width of approximately 10 mm. Immediately afterwards, a tensile load is applied to the paper in the vertical direction, and the reading (digital value) is read when the paper breaks. Five sets of samples are prepared in both the vertical and horizontal directions, and measurements are taken five times in each direction, with the average of these measurements being taken as the wet tensile strength in each direction.

On the other hand, the toilet paper of this embodiment should have a water-disintegration time of 60 seconds or less, preferably 20 seconds or more and 45 seconds or less. Water-disintegration time of 60 seconds or less reduces the risk of clogging pipes when disposed of in a flush toilet or similar. Furthermore, a time of 20 seconds or more reduces the risk of the fibers immediately unraveling and tearing when wiping away a large amount of water after using a shower toilet. This water-disintegration time (ease of unraveling) is measured in accordance with JIS P 4501 (1993). To test for ease of unraveling, a 300 mL beaker containing 300 mL of water (water temperature 20±5°C) is placed on a magnetic stirrer, and the rotor speed is adjusted to 600±10 rpm. A test specimen measuring 100±2 mm square is placed in the beaker, and a stopwatch is started. The rotor speed initially drops to approximately 500 rpm due to the resistance of the test specimen, and then increases as the test specimen unravels. The stopwatch is stopped when the rotation speed recovers to 540 rotations, and the time is measured in 1-second increments. The test is performed five times and the result of the ease of unraveling is expressed as the average. The rotor is a disk with a diameter of 35 mm and a thickness of 12 mm.

On the other hand, it is desirable for the toilet paper according to this embodiment to have a penetration count of 9 or more sheets. To measure the penetration count, stack multiple sheets of toilet paper under their own weight, drip 100 μL of water from 10 mm above the topmost sheet of toilet paper, and immediately check for penetration into the bottom layer. Start with a small number of layers and increase the number of layers until penetration is no longer noticeable, and measure the maximum number of layers at which penetration can be confirmed. If the number exceeds 9 sheets, it can be said that water penetrates extremely quickly.

Furthermore, the toilet paper according to this embodiment preferably has perforations arranged at predetermined intervals along the length. The perforation spacing is not limited, but can be 100 to 120 mm. The perforation strength is preferably 580 to 700 cN/114 mm. The perforation strength is measured in accordance with the dry tensile strength measurement method based on JIS P 8113 (2006). The measurement sample is 200 mm long and the full width of the toilet paper product, with the perforation centered along the length. The measurement is performed by folding the sample in half or quarters along the length (corresponding to the MD axis) to a width that can be clamped by the chuck of the tensile tester, with a grip distance of 100 mm and a tensile speed of 100 mm/min. This measurement is performed five times, converted to a width of 114 mm, and the average value is taken as the perforation strength.

The testing machine used may be a Minebea Co., Ltd. load cell tensile testing machine TG-200N or an equivalent machine.

Furthermore, the physical properties and composition of the toilet rolls in Examples and Comparative Examples of the present invention, such as water disintegrability and number of sheets per sheet, were measured. Furthermore, sensory evaluation tests were conducted on the following items: "Roll firmness (roll hardness)," "Roll surface feel," "Daily roll replacement frequency," "Toilet paper thickness (feeling of security during use)," "Toilet paper softness," "Toilet paper fluffiness," "Toilet paper smoothness," and "Toilet paper wiping feel." This sensory evaluation test involved 20 subjects actually using the toilet rolls and evaluating each item. The evaluation also used Comparative Example 1, a conventional two-ply product, as the reference sample. The evaluation was conducted on a seven-point scale, with the reference sample receiving 4 points, and compared against each other, with 7 points representing exceptionally good, 6 points representing good, 5 points representing somewhat good, and 3 points representing somewhat poor. 2 points representing poor, and 1 point representing particularly poor, and the average score was calculated. Regarding "roll firmness (roll hardness)," samples that were harder than the reference sample were given a higher score, and samples that were softer were given a lower score.

In the examples and comparative examples, toilet paper was used that was made into two plies by laminating a first sheet and a second sheet, each having a first recess and a second recess on the same surface, with the first recess and second recess formed on the outer surface. The second sheet had a recess formed therein with the same shape and depth as the second recess of the first sheet. The shapes of the first recess and second recess in Examples 1 to 7, Comparative Example 1, and Comparative Examples 4 to 7 were the same, and the shapes of the first recess and second recess in Comparative Example 2 and Comparative Example 3 were the same.
A paper strength agent was used in each example. In Examples 1 to 7 and Comparative Examples 4 to 7, an enzyme-based paper strength agent (Hercobond 8922, manufactured by Riken Green Co., Ltd.) was used as the dry paper strength agent. Also, a temporary paper strength agent (TS4070, manufactured by Seiko PMC Co., Ltd.) was used. In Comparative Example 1, a cationized starch (DD4280, manufactured by Seiko PMC Co., Ltd.) was used as the dry paper strength agent. Also, a temporary paper strength agent (TS4070, manufactured by Seiko PMC Co., Ltd.) was used.
Other physical properties and compositions of the examples and comparative examples are shown in Table 1. The measurement methods are as described above.

As the results shown in Table 1 show, the "firmness of the roll (hardness of the roll)" tends to increase as the winding length increases. The examples according to the present invention have a longer winding length than comparative examples 1 to 3, and are rated as having firmer rolls and harder rolls. However, despite this, the feel of the roll surface is rated higher than comparative examples 1 to 3.

Furthermore, in all categories related to the texture of the toilet paper, including "thickness of the toilet paper (sense of security when using)," "softness of the toilet paper," "fluffiness of the toilet paper," "smoothness of the toilet paper," and "wiping feel of the toilet paper," the results were superior to those of Comparative Examples 1 to 3, which were wound short and loosely.

Furthermore, looking at Comparative Examples 4 to 7, it appears that the ratings tend to be slightly lower than those of Examples 1 to 7 according to the present invention.

In other words, the examples of the present invention provide toilet paper that is excellent in wiping away moisture from skin, has high absorbency, and provides a sense of security when wiping, while also providing a satisfactory texture that is soft, fluffy, and smooth.Furthermore, the roll is firm yet has an excellent feel to the touch on the surface.

The following aspects can also be proposed.
A toilet roll in which two sheets of toilet paper are adhered together via embossed recesses and wound around a paper tube,
The winding diameter is 120 mm or less, and the winding length is 34.5 to 50 m,
The toilet paper has a basis weight per ply of 13.5 to 16.0 g/m2 and a thickness of 180 to 225 μm for two plies,
The toilet paper,
a first sheet having a first recess and a second recess formed by embossing and having different depths, and a second sheet;
the first recess has an area of 1.00 to 22.0 ^mm2 and a depth of 0.17 to 0.23 mm;
The second recess has an area of 0.25 to 0.75 ^mm2 and a depth of 0.050 to 0.090 mm;
the embossing density of the first recesses is 4 to 14/cm ² and the embossing density of the second recesses is 2 to 11/cm ² ;
The first recess has an inner surface of the laminate bonded to the second sheet, and the inner surface of the second recess is not bonded to the second sheet;
The toilet paper is wound around the paper tube with the first sheet facing outward.
This is an embodiment of the toilet roll characterized by the above.

1...toilet roll, 10...toilet paper, 20...paper tube (core), L1...toilet roll reel diameter (diameter), L3...toilet roll core diameter, L2...toilet roll width.

Claims (6)

A toilet roll in which two sheets of toilet paper are adhered together via embossed recesses and wound around a paper tube,
The winding diameter is 120 mm or less, and the winding length is 34.5 to 50 m,
The toilet paper has a basis weight per ply of 13.5 to 16.0 g/m2 and a thickness of 180 to 225 μm for two plies,
The toilet paper,
a first sheet having a first recess and a second recess formed by embossing and having different depths, and a second sheet;
the first recess has an area of 1.00 to 22.0 ^mm2 and a depth of 0.17 to 0.23 mm;
The second recess has an area of 0.25 to 0.75 ^mm2 and a depth of 0.050 to 0.090 mm;
the embossing density of the first recesses is 4 to 14/cm ² and the embossing density of the second recesses is 2 to 11/cm ² ;
The first recess has an inner surface of the laminate bonded to the second sheet, and the inner surface of the second recess is not bonded to the second sheet;
The toilet paper is wound around the paper tube with the first sheet facing outward.
A toilet roll characterized by: The toilet roll according to claim 1, wherein the second sheet has recesses formed by embossing, the recesses being shallower in depth than the first recesses formed in the first sheet. The toilet roll according to claim 1 or ² , wherein the roll winding density is 0.74 to 1.30 m/ ^cm² and the roll density is 0.12 to 0.18 g/cm³. The toilet roll according to any one of claims 1 to 3, having a roll compression ratio of 0.66 to 1.50. The toilet roll according to any one of claims 1 to 4, wherein the toilet paper is treated with an enzyme-based paper strength agent. The toilet roll according to any one of claims 1 to 5, wherein the toilet paper does not contain starch and cationic starch.