JP7493328B2 - Toilet roll - Google Patents

Description

The present invention relates to a toilet roll, which is toilet paper wound into a roll.

The JIS standard specifies the length of toilet paper wound in a toilet roll as 27.5 m, 32.5 m, 55 m, 65 m, 75 m, and 100 m. There are various products in which toilet paper is wound to different lengths in response to consumer demand, but most common, commonly available products are around 55 m per ply as specified by the JIS standard.

Toilet paper is used in direct contact with the skin and is also used to wipe away feces, so softness and the ability to wipe away feces are important. Some toilet paper is embossed to provide this softness and ease of wiping away feces.

In addition, with the recent spread of shower toilets, there is now a demand for improved water absorption in toilet paper, even for popular products that are not as expensive as products made specifically for shower toilets.

When consumers purchase toilet rolls, they touch them while they are still in the toilet roll state, so they may judge the softness of the toilet paper by the hardness of the toilet roll. The diameter of a toilet roll is set at 120 mm or less in the JIS standard, and is generally around 100 to 110 mm. In order to increase the softness of the toilet roll, it is sufficient to loosely wind the toilet paper around a shaft such as a paper tube within the set diameter, but winding it too loosely can easily cause wrinkles to form between the layers of the toilet paper.

In particular, embossed toilet paper has an uneven surface, so if it is rolled loosely, the embossing is likely to be crushed when the user holds it in their hands when purchasing or replacing the toilet roll. This can also cause wrinkles. Conversely, if it is rolled tightly, the clarity of the unevenness created by the embossing is reduced.

JP 2005-348976 A JP 2018-064664 A

The main objective of the present invention is to provide a toilet roll that has an appropriate roll hardness, is less likely to cause crushing or wrinkling of the unevenness caused by the embossing when the toilet roll is held during and after production, has excellent clarity of the unevenness caused by the embossing, and has excellent water absorbency.

The first means for solving the above problem is:
A single-ply toilet paper having a paper thickness of 120 to 150 μm, a dry tensile strength in the MD direction of 190 to 310 cN/25 mm and a dry tensile strength in the CD direction of 60 to 120 cN/25 mm, and having a single embossed finish,
The length of the coil is 54.5 to 56.7 m and the coil diameter is 104 to 108 mm.
Klemm water absorption: 33-60 mm/3 min.
Softness: 2.0 to 4.5 cN,
Basis weight is 21.0 to 23.5 g/m ² ,
MMD is 7.0 to 12.0 on the front surface (the surface on which concave portions are formed by embossing) and 9.0 to 15.5 on the back surface (the surface on which convex portions are formed by embossing),
Roll hardness: 0.80 to 1.40 kgf,
The winding density is 0.83 to 0.92.
This is a toilet roll characterized by the above.
The MMD is measured by bringing the contact surface of the friction element into contact with the surface of the measurement sample to which a tension of 20 g/cm is applied in a predetermined direction at a contact pressure of 25 g, moving the friction element 2 cm in substantially the same direction as the tension at a speed of 0.1 cm/s, and measuring the friction coefficient at this time using a friction tester KES-SE (manufactured by Kato Tech Co., Ltd.) or an equivalent device. The MMD is a value obtained by dividing the friction coefficient by the friction distance (movement distance = 2 cm).
The friction element has a contact surface formed of 20 adjacent piano wires P with a diameter of 0.5 mm, and has a length and width of 10 mm. The contact surface has a unit bulge at the tip formed by 20 piano wires P (with a curvature radius of 0.25 mm).

The second method is
The embossed pattern on the toilet paper
A recess having a square bottom surface of 1.0 to 1.5 x 1.0 to 1.5 mm or a substantially square bottom surface with all four corners of the square extending diagonally outward is arranged in a lattice pattern with a center interval of 4.5 to 5.5 mm and an arrangement angle of 45° with respect to the width direction, over the entire surface of the paper,
The toilet roll according to the first aspect has valley lines extending from the four corners of the recesses between the recesses.

The third method is
The toilet roll according to the first or second aspect of the present invention contains a softener, a moisturizer, and a tackifier.

According to the present invention, a toilet roll is provided that has an appropriate roll hardness, is less likely to cause crushing or wrinkling of the embossed unevenness when the toilet roll is held, has excellent clarity of the embossed unevenness, and has excellent water absorbency.

FIG. 1 is a perspective view of a toilet roll according to an embodiment. FIG. 2 is a plan view of an embossment according to the embodiment. FIG. 4 is a schematic diagram for explaining a procedure for measuring an embossing depth according to an embodiment. FIG. 1 is a diagram for explaining a method for measuring MMD. FIG. 13 is a diagram showing the results of a water absorbency test according to the embodiment.

Next, the toilet roll of this embodiment will be explained with reference to the drawings.

The toilet roll of this embodiment has a paper thickness of 120 to 150 μm, a dry tensile strength in the MD direction of 190 to 310 cN/25 mm or more and a dry tensile strength in the CD direction of 60 to 120 cN/25 mm, and one ply of embossed toilet paper is wound to a length of 54.5 to 56.7 m around a tube shaft with an outer diameter of 35 to 45 mm, with a roll diameter of 104 to 108 mm.

By adopting these configurations, the roll has an appropriate hardness, and the unevenness caused by the embossing is less likely to be crushed or wrinkled when the toilet roll is held during and after production, and the unevenness caused by the embossing is excellent in clarity. Furthermore, it is even better if the Klemm water absorbency is 33 to 60 mm/3 minutes. Each configuration will be described in detail below.

JIS P 4501 stipulates that the roll diameter of a toilet roll is 120 mm or less, and holders for setting general toilet rolls are made based on this 120 mm standard. The roll diameter L2 (diameter) of the toilet paper in this embodiment is 104 to 108 mm, which is a roll diameter that can be easily set in a general holder. Here, the roll diameter is a value measured using a diameter rule manufactured by Muratec KDS Corporation or an equivalent machine. 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.

The toilet roll according to this embodiment has a roll length of 54.5 to 56.7 m for one ply of toilet paper. Conventional one ply products for general households have a roll length of around 55 m, and the toilet roll according to this embodiment is ensured to have a roll length similar to that of general products. The roll length is measured while unrolling the toilet roll without applying tension. For example, it may be measured while folding back in a zigzag pattern every 5 m from the unrolling stage.

The core diameter of a toilet roll is set at 38 mm ± 1 mm in JIS P 4501, and although this standard is used as a reference, in reality there are various core diameters depending on the product. The outer diameter of the tube shaft according to this embodiment is 35 to 45 mm, which is within the range of general products, and can be used sufficiently in toilet roll holders that rotate the toilet roll by passing the shaft through a shaft core. Furthermore, by setting the outer diameter of the tube shaft according to this embodiment, it is possible to achieve an appropriate roll hardness when the toilet paper according to the present invention is wound to the above-mentioned winding length. In addition, it is possible to make it difficult for the unevenness caused by the embossing process to be crushed or wrinkled when the toilet roll is held.

The width of the toilet roll is not limited, but is generally 110 to 120 mm, and it is desirable for the toilet roll of this embodiment to be in this range as well.

The toilet paper according to this embodiment is one ply, and its thickness is 120 to 150 μm. If it is two plies or more, the roll cannot have an appropriate hardness in relation to other configurations. In other words, the effect of the present invention is not realized. This paper thickness is somewhat thick among popular toilet paper products. By setting the paper thickness within the range of the present invention, the unevenness caused by the embossing process becomes clear. Here, the method of measuring the paper thickness is to sufficiently condition the test piece under the conditions of JIS P 8111 (1998) (usually for about 8 hours), and then measure the thickness in one ply state under the same conditions using a dial thickness gauge (thickness measuring instrument) "PEACOCK G type" (manufactured by Ozaki Manufacturing Co., Ltd.). Specifically, after confirming that there is no dirt or dust between the plunger and the measuring table, the plunger is lowered onto the measuring table, the dial thickness gauge is moved to set the zero point, and then the plunger is raised and the sample is placed on the test table, and the plunger is slowly lowered and the gauge at that time is read. In this case, the toilet paper according to the present invention has unevenness due to the embossing process, so one of the concave (convex) parts of the embossing must be within the range of the measurement table. If the embossing pattern is composed of a group of concaves with different depths, the deepest concave part must be located. During this measurement, the plunger is simply placed on the paper without being pressed down. The plunger terminal is made of metal, and the circular flat surface with a diameter of 10 mm is placed perpendicularly against the paper plane, and the load during this paper thickness measurement is approximately 70 gf. The paper thickness is the average value obtained by performing 10 measurements. Here, when measuring the paper thickness, it is assumed that the embossment (concave) will be crushed, but the paper thickness according to the present invention is a value measured including such crushing, and such crushing can be ignored. In this paper thickness measurement, the difference in paper thickness caused by the crushing of the concave part can be ignored.

The toilet paper according to this embodiment has a dry tensile strength of 190 to 310 cN/25 mm in the MD direction (longitudinal direction) and 60 to 120 cN/25 mm in the CD direction (horizontal direction). More preferably, the dry tensile strength of 235 to 250 cN/25 mm in the MD direction (longitudinal direction) and 90 to 110 cN/25 mm in the CD direction (horizontal direction). By setting the dry tensile strength within the above range, the toilet roll does not feel excessively hard when used. In addition, even with the winding length and winding diameter of the toilet roll, the unevenness caused by the embossing is excellent in clarity, and there are no wrinkles or there are very few wrinkles that are greatly improved. In other words, the unevenness caused by the embossing is not excessively stretched during manufacturing, and wrinkles are very unlikely to occur. The dry tensile strength is measured based on the tensile test of JIS P 8113 (2006). The test pieces are cut to about 25 mm (±0.5 mm) wide x 150 mm long in both the vertical and horizontal directions. The tester is a load cell tensile tester TG-200N manufactured by Minebea Co., Ltd. or an equivalent. The gripping distance is set to 100 mm. The measurement is performed by clamping both ends of the test piece to the grips of the tester, applying a tensile load in the vertical direction to the paper piece, and reading the indicated value (digital value) when the paper breaks. The tensile speed is 100 mm/min. Five sets of samples are prepared in both the vertical and horizontal directions, and measurements are taken five times each. The average of the measured values is the dry tensile strength in each direction. The sample is adjusted in accordance with JIS P 8111 (1998). The dry tensile strength can be adjusted by a known method as long as it does not interfere with the effects of the present invention.

On the other hand, in order to adjust the dry tensile strength and further improve the softness of the toilet paper, it is desirable that a softener, a moisturizer, and a tackifier are added to the toilet paper according to this embodiment. These softeners, moisturizers, and tackifiers are added internally during papermaking to adjust the softness and paper strength of the base paper itself. The softeners, tackifiers, and tackifiers can be appropriately selected from among the internal softeners, internal moisturizers, and tackifiers for pulp slurry used in toilet paper. Examples of the softener include fatty acid ester compounds. The fatty acid ester compounds may be either cationic fatty acid ester compounds or nonionic fatty acid ester compounds, and multiple types may be added. Furthermore, for example, one or more of the fatty acid ester-based softeners disclosed in U.S. Pat. No. 3,296,065 and the like, quaternary ammonium salt-type cationic surfactants disclosed in JP-A-48-22701 and the like, non-cationic surfactants disclosed in JP-A-2-99690 and JP-A-2-99691 and the like, urethane alcohols or their salts or cationized products disclosed in JP-A-60-139897 and the like, polyphosphates disclosed in JP-A-2-36288 and the like, polysiloxanes disclosed in JP-A-2-224626 and JP-A-3-900 and the like can be appropriately selected and used. Preferred examples include those containing a nonionic surfactant (component A) having an alkyl group and/or an alkenyl group and a cationic surfactant (component B) having an alkyl group and/or an alkenyl group. In the latter case, it is particularly desirable that the nonionic surfactant (component A) has an alkyl group having 6 to 24 carbon atoms and/or an alkenyl group having 6 to 24 carbon atoms as the hydrophobic portion. If the carbon number of component A is less than 6, the softening effect may not be enhanced, and if the carbon number exceeds 24, dispersibility may be poor when added to a papermaking system. Examples of moisturizing agents include cationic polyethylene emulsions, fatty acid amides, and fatty acid amide compounds. Examples of thickeners include polyethylene oxide (polyethylene glycol) thickeners.

The toilet paper according to this embodiment preferably has a softness of 2.0 to 4.5 cN as measured by the handle-o-meter method in accordance with JIS L 1096 (2010) Method E. More preferably, it is 2.4 to 4.5 cN, and especially 2.5 to 4.0 cN. This range can be adjusted by adding fabric softeners, moisturizers, viscosity agents, and even embossing patterns. If the softness is in the range of 2.0 to 4.5 cN, the toilet paper will feel soft when in use.

The toilet paper according to this embodiment is not necessarily limited in basis weight, but the basis weight is desirably 21.0 to 23.5 g/ ^m2 . Preferably, it is 21.5 to 23.0 g/ ^m2 . More preferably, it is 21.8 to 22.8 g/ ^m2 . By setting the basis weight within this range within the above-mentioned range of paper thickness, it is easy to adjust the dry tensile strength to the range and excellent water absorbency is expressed. In particular, when making the unevenness by embossing clearer, if the paper thickness is thick and the basis weight is high, the fibers in the pressed parts may become tighter and the water absorbency may decrease, but in the configuration of the toilet roll according to this embodiment, the water absorbency is further increased within the above-mentioned range of paper thickness and basis weight.

The toilet paper according to this embodiment is embossed. The toilet paper is embossed, so it becomes soft in the bending direction, and the unevenness of the surface makes it excellent at wiping off feces. In addition, when the toilet paper is embossed, the unevenness of the paper surface creates spaces between the layers when it is wound into a roll, and these spaces make it easier for the roll to express its softness. The embossing is a type of embossing called single embossing, in which only recesses are present on one side and only protrusions corresponding to the recesses are present on the other side. The toilet roll according to this embodiment is wound with the recessed side as the outer side.

The embossing pattern is not necessarily limited. Any suitable embossing pattern such as microembossing, dot-type embossing, design embossing, etc. may be used. However, a suitable embossing pattern has a recessed area of 1.0 to 2.5 ^mm2 , a density of 0.01 to 0.5 pieces/ ^mm2 , and an embossing depth of 0.02 to 0.5 mm. The softness of the toilet paper is improved, and the softness of the rolled paper such as a toilet roll is also increased, making it easier for consumers to feel that the paper is soft when held in their hands, and the unevenness caused by the embossing process is not easily crushed and has excellent clarity. In particular, as shown in FIG. 2, the recesses 31 (FIG. 2A) are square in shape with a bottom surface of diagonal L4×diagonal L4=1.0-1.5×1.0-1.5 mm, or the recesses 32 are substantially square in shape with the four corners of the square extending diagonally outward (FIG. 2B), and are arranged in a lattice pattern with a center distance L5 of 4.5-5.5 mm and an arrangement angle of 45° with respect to the width direction, and between the recesses 31 (32) there are valley lines 33 extending from the four corners of the recesses. It is preferable that the valley lines 33 are arranged in a gradually gradual bow shape in cross section so that the four corners of the recesses 31 (32) are the deepest and the middle between the recesses is the shallowest. In this embossing pattern, the valley lines distribute tension during winding toward 45° in the width direction, and the unevenness caused by the embossing becomes very clear in the winding length of the toilet roll according to the present invention, and wrinkles are unlikely to occur. In addition, the toilet paper itself is excellent in terms of softness and feces wiping ability. The embossing depth is the average depth of the recesses.

The depth of the recesses created by the embossing process is measured using a one-shot 3D measuring macroscope VR-3200 manufactured by Keyence Corporation or an equivalent device, and image analysis software "VR-H1A" or an equivalent software. Measurements are performed under conditions of a magnification of 12 times and a field of view area of 24 mm x 18 mm. However, the magnification and field of view area can be changed as appropriate depending on the size of the embossment (recess). The specific measurement procedure will be explained with reference to Figure 3. Using the above software, etc., an emboss depth (measured cross-sectional curve) profile is obtained at line segment Q1 that crosses the longest part of the periphery of one embossment (recess) 40 in the image area (part X in the figure) shown in a plan view. From the cross-sectional curve of this emboss depth profile, surface roughness components with wavelengths shorter than λc: 800 μm (where λc is the "filter defining the boundary between roughness and waviness components" described in JIS-B0601 "3.1.1.2") are removed by a low-pass filter, and the "contour curve Q2" of the image portion (Y portion in the figure) shown from the cross-sectional viewpoint is obtained. Two recess edge points P1, P2 that are upwardly convex and have the strongest curve, and the minimum value sandwiched between the recess edge points P1, P2 are obtained, and this is defined as the minimum depth value Min. Furthermore, the average value of the depth values of the recess edge points P1, P2 is defined as the maximum depth value Max. In this way, the emboss depth = maximum value Max - minimum value Min. The distance (length) on the XY plane of the recess edge points P1, P2 is defined as the length of the longest portion. The two recess edge points P1, P2 that are upwardly convex and have the strongest curve are selected by visual inspection. In addition, when making this selection, the contour E in the plan view image of the embossment (depression) 40 being measured may be used as a reference. Similarly, the depth of the embossment (depression) is also measured for the shortest part in the direction perpendicular to the longest part, and the larger value is adopted as the depth of the embossment (depression). The above measurements are performed on any 10 embossments on the toilet paper surface, and the average value is taken as the final embossment depth.

The toilet paper according to this embodiment has an MMD value, which is an index of surface properties, of 7.0 to 12.0, preferably 8.0 to 10.0 on the surface (surface having concave portions), and 9.0 to 15.5, preferably 10.0 to 11.0 on the back surface (surface having convex portions). In addition, since the toilet paper according to this embodiment has concaves and convexes formed in the form of a single embossing, the MMD value, which is an index of surface properties, is higher on the back surface (surface having convex portions) than on the front surface (surface having concave portions). If the MMD is within this range, the toilet paper will feel smooth without feeling rough as toilet paper when used. Moreover, since the MMD value is a surface property, it is affected by the concaves and convexes caused by the embossing process. If the toilet roll is wrapped with tissue paper having concaves and convexes caused by the embossing process in this range, the softness will be felt extremely when held in the hand. In addition, friction between the toilet paper layers in the rolled state is moderate, making it less likely for wrinkles or embossing to be crushed during production, and the embossing is clear and wrinkles are prevented.
The MMD is measured using a measuring device 100 shown in FIG. 4. The contact surface of the frictional element is brought into contact with the surface of the measurement sample to which a tension of 20 g/cm is applied in a predetermined direction at a contact pressure of 25 g, and the frictional element is moved 2 cm in the direction substantially the same as the direction in which the tension is applied at a speed of 0.1 cm/s, and the friction coefficient at this time is measured using a friction tester KES-SE (manufactured by Kato Tech Co., Ltd.) or an equivalent device. The value obtained by dividing the friction coefficient by the friction distance (movement distance = 2 cm) is the MMD. The frictional element is made of 20 piano wires P with a diameter of 0.5 mm arranged adjacent to each other, and has a contact surface formed so that both the length and width are 10 mm. The contact surface is formed with a unit bulge at the tip formed by 20 piano wires P (radius of curvature 0.25 mm).

Furthermore, the toilet paper according to this embodiment has a Klemm absorbency of 33 to 60 mm/3 minutes, preferably 35 to 50 mm/3 minutes. If the Klemm absorbency is 33 mm/3 minutes or more, it is an unprecedented high absorbency among general-purpose products with a roll length of about 55 m per ply. Regarding the upper limit, in the case of a single ply, if it is too high, the sense of security decreases, for example, when wiping urine or using it in a shower toilet. If it is 60 mm/3 minutes or less, it does not absorb excessively and is easy to use with confidence even as a general-purpose product with one ply. In addition, it is easy to ensure water disintegration. Here, the Klemm absorbency according to this embodiment is measured in accordance with JIS P 8141. The sample is 15 mm wide and 200 mm long or more according to JIS P 8141, but while JIS P 8141 specifies a measurement time of 10 minutes, this Klemm absorbency is measured for 3 minutes, and the distance penetrated after 3 minutes is taken as the measurement time. This is because toilet paper is highly hydrolyzable and may not be measured after 10 minutes of immersion, and the amount of water absorbed in a much shorter time than 10 minutes, specifically up to about 3 minutes, is important in actual use of toilet paper. In addition, the Klemm absorbency in a short time of 3 minutes is also affected by the unevenness of the embossing. In the unevenness of the embossing, the fibers are strongly compressed in deep and clear recesses, and weakly compressed in shallow and unclear recesses. The fiber density differs depending on the clarity and depth of the embossing, so the Klemm absorbency in a short time differs.

Furthermore, it is desirable that the number of sheets that penetrate the toilet paper according to this embodiment when 100 μL of water is dripped onto it is 9 or more. To measure the number of sheets that penetrate, multiple sheets of toilet paper are stacked under their own weight alone, and 100 μL of water is dripped onto the toilet paper 10 mm above the topmost sheet, and the penetration into the bottom layer is immediately confirmed after the dripping. Starting with a small number of layers, the number of layers is increased until penetration is no longer noticeable, and the maximum number of sheets at which penetration can be confirmed is measured. 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 a water absorbency of 0.72 mL or more at a basis weight of 21.5 g/ ^m2 or less. Furthermore, it is preferably 0.68 mL or ^more at a basis weight of more than 21.5 g/ ^m2 and less than 21.9 g/ ^m2 , and 0.62 mL or more at a basis weight of more than 21.9 g/m2 and more than 22.3 g/ ^m2 . As the basis weight increases, the water absorbency may decrease, but within the above range, the water absorbency can be said to be excellent.

Here, the absorbency test was conducted by using 20 sheets of toilet paper stacked as a sample, dripping water onto a single point on the sample at a constant rate, and confirming the amount of water dripped when a detector detects that the sample can no longer retain the water and that it has penetrated to the opposite side from the side where it was dripped. Specifically, 20 sheets of toilet paper are stacked together and fixed in the stacked state with a sample holder. Next, water is dripped onto one side of the sample at a rate of 10 ± 2 mL/min from a position 10 mm above the sample. A water detector is placed below the sample in contact with it, and the amount of water dripped when the detector detects that water has penetrated the sample is taken as the absorbency.

On the other hand, the toilet roll according to this embodiment desirably has a winding hardness of 0.80 to 1.40 kgf. The winding hardness according to this invention is the value obtained by winding a diameter rule (manufactured by Muratec KDS Corporation or an equivalent machine) around the toilet roll and measuring the force required to pull it three graduations on a push-pull gauge (manufactured by Imada Corporation or an equivalent machine). If the winding hardness is 0.80 to 1.20 kgf, it is difficult to feel that it is hard compared to the winding length. With the above-mentioned configuration according to this invention, it is easy to adjust the winding hardness to this value.

On the other hand, the toilet roll according to the present embodiment preferably has a winding density of 0.83 to 0.92. The winding density is a value calculated by dividing the actual cross-sectional area by the theoretical cross-sectional area. The actual cross-sectional area is a value calculated by multiplying the winding length by the paper thickness. On the other hand, the theoretical cross-sectional area is a value calculated by (winding diameter/2) x (winding diameter/2) x π - (outer diameter of the paper tube/2) x (outer diameter of the paper tube/2) x π. In other words, it is the area obtained by subtracting the area of the open end side of the paper tube from the area of the end face. If the winding density is in the range of 0.83 to 1.10, the roll will not feel hard compared to the winding length when held by the hand at the circumferential surface. In particular, if it exceeds 1.10, it will start to feel excessively hard, and if it is 0.96 or more, it will feel like a tightly wound roll. On the other hand, if it is less than 0.83, there is a risk that the center of the roll will protrude from the end face.

Next, the method for manufacturing the toilet roll of this embodiment will be described. The method for manufacturing the toilet roll of this embodiment includes a papermaking process for obtaining base paper, and a winding process for winding the base paper with a winder device. Each process will be described below.

[Papermaking process]
The papermaking process in this embodiment can be carried out using a papermaking machine for crepe paper using the dry crepe method. First, in the papermaking process, a pulp slurry is prepared. The freeness of the pulp slurry is appropriately adjusted between 410 and 680 cc.

In the pulp slurry of this embodiment, the fiber raw material is 70 to 100% virgin pulp by mass. Other fiber raw materials such as waste paper pulp can be contained in an amount of 0 to 30% by mass. It is particularly preferable that the raw material is 100% virgin pulp by mass, since it is easy to adjust the texture such as softness and smoothness and the paper strength. However, when waste paper pulp is blended, there is an advantage that it can be manufactured more inexpensively than one consisting of 100% virgin pulp by mass. In addition, in the process of regenerating pulp from waste paper, the fibers of waste paper pulp tend to become finer than the pulp fibers before regeneration, and due to the nature of such fibers, the fibers become dense and the paper strength can be increased without increasing the paper thickness. On the other hand, if it is blended excessively, the texture such as flexibility decreases. Therefore, in consideration of the characteristics of the waste paper pulp, the blending ratio may be set in the range of 0 to 30% by mass. The type of waste paper pulp is not necessarily limited, but waste paper pulp made from milk carton waste paper and high-quality waste paper is particularly preferable. These contain a large amount of hardwood kraft pulp (LBKP) derived from the raw materials, making them easy to develop paper strength.

The virgin pulp is preferably softwood kraft pulp (NBKP) and hardwood kraft pulp (LBKP). The blend ratio of these is preferably NBKP:LBKP 20:80 to 50:50.

Next, 0.9 to 1.0 kg/t pulp of softener, 1.4 to 1.6 kg/t pulp of moisturizer, and 0.45 to 0.55 kg/t pulp of adhesive are supplied to the pulp slurry. However, the softener, moisturizer, and adhesive do not need to be supplied at the same time, and can be supplied separately at an appropriate position before the papermaking raw material is discharged onto the papermaking net. Preferably, the softener is supplied in a mixing tank, and the moisturizer is supplied in a seed box. The adhesive is supplied prior to these. By blending the softener and moisturizer in the above ratios, the softness of the toilet paper is improved, and it is also easier to create unevenness due to embossing.

The softener, moisturizer, and thickener can be appropriately selected from among the internal softeners, internal moisturizers, and thickeners for pulp slurry used in the manufacture of toilet paper. As the softener, for example, one or more of the fatty acid ester-based softeners disclosed in U.S. Pat. No. 3,296,065, quaternary ammonium salt-type cationic surfactants disclosed in JP-A-48-22701, non-cationic surfactants disclosed in JP-A-2-99690 and JP-A-2-99691, urethane alcohols or their salts or cationized products disclosed in JP-A-60-139897, polyphosphates disclosed in JP-A-2-36288, polysiloxanes disclosed in JP-A-2-224626 and JP-A-3-900, etc. can be appropriately selected and used. Preferably, the surfactant contains a nonionic surfactant (component A) having an alkyl group and/or an alkenyl group and a cationic surfactant (component B) having an alkyl group and/or an alkenyl group. In the latter case, it is particularly preferable that the nonionic surfactant (component A) has an alkyl group having 6 to 24 carbon atoms and/or an alkenyl group having 6 to 24 carbon atoms as the hydrophobic part. If the carbon number of component A is less than 6, the softening effect may not be enhanced, and if the carbon number exceeds 24, the dispersibility when added to a papermaking system may be poor.

Moisturizing agents include cationic polyethylene emulsions and fatty acid amides.

As a thickening agent, polyethylene oxide-based thickening agents are preferred because they can further improve the texture.

In particular, in adjusting the papermaking raw materials in the papermaking process of this embodiment, it is advisable to use a slightly larger amount of adhesive. This increases the dry tensile strength, reduces the tension (draw) in the winder, and slows down the speed during embossing to form clear unevenness. On the other hand, a slightly larger amount of softener and a slightly smaller amount of moisturizer are used. This reduces the hardness of the paper caused by the adhesive, making it easier to achieve the softness required for toilet paper and toilet rolls after embossing, and also makes it less likely for wrinkles to occur during production.

The papermaking speed (machining speed) when making the base paper should be 850 to 920 m/min. This allows enough time for the fibers to blend together and for chemicals such as fabric softeners to take effect.

Drying of the wet paper in the papermaking process can be carried out in a drum dryer. The dry paper dried in the drum dryer is creped with a creping doctor, appropriately calendared, and then wound up into a roll of raw paper. Here, in this embodiment, the crepe is formed with a creping doctor blade angle of 89 to 91° during creping. The bevel angle may be 17 to 19°. The crepe rate is about 19 to 22%. By increasing the creping doctor blade angle, a firm crepe is formed on the base paper, and the thick base paper results in toilet paper with clear unevenness during embossing.

The dry tensile strength of the base paper should be about 1.1 to 1.3 times the dry tensile strength of the toilet paper when made into a toilet roll.

[Winding process]
The winding process in this embodiment can be performed by a winder device having an embossing facility built in. In this embodiment, prior to or in parallel with the winding process, a base paper unwound from a raw roll is processed and then wound around a long paper tube having a length multiple times the product width of the toilet roll produced, to form a log, which is an intermediate product having the same diameter as the diameter of the final toilet roll product and a width corresponding to multiples of the final product.

In this winding process, the raw paper roll wound with the base paper obtained in the papermaking process is set in a winder device. In the winder device, the base paper unwound from the raw paper roll is first embossed. The embossing in this embodiment is single embossing using the steel rubber method. The steel rubber method is an embossing method in which the base paper is passed between a metal embossing roll on whose surface convex portions corresponding to the embossed pattern are formed and a mating rubber roll with a resin surface, and the embossing pattern on the embossing roll's circumferential surface is transferred to the base paper by pressing the embossing roll's circumferential surface against the base paper. In this case, recesses are formed on the surface of the base paper facing the embossing roll, and protrusions corresponding to the recesses are formed on the surface in contact with the rubber roll.

The height of the convex portion formed on the embossing roll may be adjusted as appropriate depending on the embossing depth, but is preferably 1.2 to 1.5 mm. The Shore hardness of the rubber roll can be adjusted within an appropriate range, but in this embodiment, it is preferable to perform embossing using a rubber roll made of a material with a slightly high Shore hardness of more than 60, more preferably more than 70. In the comparative example, a rubber roll with a Shore hardness of 45 to 50 is used. In general, increasing the Shore hardness of the rubber roll leads to a blurred embossing, but if the material is low, the rubber roll will deform and the embossing will not be performed properly. In the present invention, the Shore hardness of the rubber roll is appropriately increased to make the unevenness caused by the embossing process continuously clear.

In this embodiment, the embossing pattern of the embossing roll is not necessarily limited, but as described above, it is preferable that the area of the recess is 1.0 to 2.5 ^mm2 , the density is 0.01 to 0.5, and the embossing depth is 0.02 to 0.5 mm to form the unevenness. The softness of the toilet paper is improved, and the softness in the roll state like a toilet roll is increased, so that the consumer feels it is soft when holding it in his hand, and the unevenness caused by the embossing is not easily crushed and is excellent in clarity. In particular, it is preferable that the pattern shown in FIG. 2 above is transferred. The tension during winding is distributed, and the unevenness caused by the embossing becomes extremely clear in the winding length of the toilet roll according to the present invention, and wrinkles are unlikely to occur. In addition, the softness of the toilet paper itself and the wiping ability of feces are also excellent. The embossing depth is the average value of the depth of the recess.

The base paper on which the unevenness is formed by embossing is wound around a long paper tube with an outer diameter of 35 to 45 mm by the surface winding method. The winding length is 54.5 to 56.7 m to produce the toilet roll of this embodiment. At this time, the tension is adjusted so that the winding diameter is 104 to 108 mm. Here, when manufacturing the toilet roll of this embodiment, it is preferable to adjust the draw value between the winding belt and the drum. This draw value is a value calculated by {(winding belt speed) - (winding drum speed)} / (winding belt speed). In other words, it represents the level of tension during winding. By adjusting the draw value, the processing speed during embossing can also be adjusted. In this embodiment, the draw value is 5.0% or less, preferably 3.0% or less. By setting the draw value to 5.0% or less, the speed during embossing can be slowed down to form clear unevenness, and further, wrinkles and crushing of the unevenness during winding are preferably prevented.

Prior to winding, perforations can be applied using a perforation line forming section equipped with a perforation roll built into the winder device.

Once the logs have been produced as described above, they are cut to the product width in a downstream log cutter to make individual toilet rolls.

Next, the examples and comparative examples of the toilet roll of the present invention were tested for roll softness, paper (toilet paper) softness, smoothness, moistness, thickness, and clarity of embossed unevenness. Furthermore, several examples and comparative examples with different basis weights were produced and tested for Klemm's water absorbency, number of sheets permeated with 100 mL of water, and water absorption capacity.

Each example and comparative example has an embossed pattern as shown in Figure 2B (diagonal distance 1.0 x 1.0, pitch 5.0 mm). The configuration of the toilet roll and the physical properties and composition of the toilet paper for each example are shown in Tables 1 and 2 below.

For the sensory evaluation, 18 test subjects actually used the toilet rolls of each example for one week and evaluated them in the following categories: "softness of the roll," "softness of the paper," "smoothness of the paper," "moist feeling of the paper," "thickness of the paper," and "sharpness of the embossing." The comparative example was given a score of 4 points, followed by 5 points for better than the comparative example, 4 points for the same as the comparative example, 3 points for slightly better than the comparative example, 2 points for better than the comparative example, and 1 point for much better than the comparative example, and the average of these scores was calculated to make a judgment. The test for the sharpness of the embossing involved the evaluator visually judging whether the embossing was sharp from the start to the end of the roll.

The methods for testing Klemm absorbency, the number of sheets permeated with 100 mL of water, and absorbency are as described above. The Klemm absorbency is the average value calculated from five measurements for each sample number. The results are shown in Table 2. Klemm absorbency is the distance permeated three minutes after the start of measurement, in accordance with JIS P 8141. The number of sheets permeated with 100 mL of water started at five, and was increased accordingly. The sample holder for absorbency is a ring-shaped frame with a sufficient drip area so that water dripped into the center does not penetrate to the frame.

As shown in Table 1, the Examples according to the present invention performed better than the Comparative Examples in all sensory evaluations. In addition, the water absorption capacity of both the Examples and Comparative Examples decreased as the basis weight increased. This is thought to be because in toilet paper with unevenness due to embossing, the paper is pressed by the embossing process, so when the basis weight is high, the paper tends to become denser in the thickness direction. However, as shown in Figure 5, it can be seen that the Examples have higher water absorption capacity than the Comparative Examples at the same basis weight. In addition, in the tests of the number of sheets permeated and Klemm's water absorbency, the Comparative Examples performed better than the Examples.

Taking these results together, the toilet roll of the present invention has excellent roll softness, is less likely to crush or wrinkle the unevenness caused by the embossing when the toilet roll is held, has excellent clarity of the unevenness caused by the embossing, and has excellent water absorption performance.

1...toilet roll, 10...toilet paper, 20...paper tube (tube core), L1...toilet roll winding diameter (diameter), L2...diameter of toilet roll tube core, L3...toilet roll width, 31, 32...recesses, 33...valley line portion.

Claims (2)

A single-ply toilet paper having a paper thickness of 120 to 150 μm, a dry tensile strength in the MD direction of 190 to 310 cN/25 mm and a dry tensile strength in the CD direction of 60 to 120 cN/25 mm, and having a single embossed finish.
The length of the coil is 54.5 to 56.7 m and the coil diameter is 104 to 108 mm.
Klemm water absorption: 33-60 mm/3 min.
Softness: 2.0 to 4.5 cN,
Basis weight is 21.0 to 23.5 g/m ² ,
MMD is 7.0 to 12.0 on the front surface (the surface on which concave portions are formed by embossing) and 9.0 to 15.5 on the back surface (the surface on which convex portions are formed by embossing),
Roll hardness: 0.80 to 1.40 kgf,
The winding density is 0.83 to 0.92;
Includes internal softeners, internal moisturizers, and viscosity agents for pulp slurry
A toilet roll characterized by:
The MMD is measured by bringing the contact surface of the friction element into contact with the surface of the measurement sample to which a tension of 20 g/cm is applied in a predetermined direction at a contact pressure of 25 g, moving the friction element 2 cm in substantially the same direction as the tension at a speed of 0.1 cm/s, and measuring the friction coefficient at this time using a friction tester KES-SE (manufactured by Kato Tech Co., Ltd.) or an equivalent device. The MMD is a value obtained by dividing the friction coefficient by the friction distance (movement distance = 2 cm).
The friction element has a contact surface formed of 20 adjacent piano wires P with a diameter of 0.5 mm, and has a length and width of 10 mm. The contact surface has a unit bulge at the tip formed by 20 piano wires P (with a curvature radius of 0.25 mm). The embossed pattern on the toilet paper
A recess having a square bottom surface of 1.0 to 1.5 x 1.0 to 1.5 mm or a substantially square bottom surface with all four corners of the square extending diagonally outward is arranged in a lattice pattern with a center interval of 4.5 to 5.5 mm and an arrangement angle of 45° with respect to the width direction, over the entire surface of the paper,
2. The toilet roll according to claim 1, further comprising a valley portion extending from each of the four corners of the recess between adjacent recesses.

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