toilet roll

Abstract

To provide a toilet roll in which patterns superior in design properties are visible while being a long article, and furthermore wrinkles and kinks are reduced, and thereby surface smoothness is easy to feel.SOLUTION: A toilet roll is provided by making toilet tissue paper of 2-ply into a roll and having a roll diameter of 90-120 mm. In the toilet tissue paper, irregularities by embossing are provided, patterns formed by halftone dot printing and solid typesetting are printed on one side, a ratio of a total area of a pattern portion is 8-20%, a ratio of a total area of a halftone dot portion is 6.0% or more, a ratio of a total area of a solid portion is 4.0% or less, and a paper thickness of 1-ply is 60-90 μm. The toilet tissue paper is rolled around a paper tube of 65-90 m with a roll density of 0.83-2.05 so that the surface with the patterns printed thereon may become an outer layer side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a toilet roll in which toilet paper is wound into a roll shape. [Background technology]

[0002] Toilet rolls are everyday necessities, and because toilet spaces are limited, the length of the roll is an important factor for consumers when deciding whether to purchase them.

[0003] While the typical roll length for toilet paper rolls intended for general households was around 25m for double-ply rolls (also known as double-ply) and around 50m for single-ply rolls (also known as single-ply), longer rolls with 1.5 to 3 times that length are becoming increasingly popular in recent years (see Patent Document 1 below).

[0004] For these long toilet rolls, in order to achieve a roll diameter that can be used with commonly used household toilet paper holders, the toilet paper needs to have a low basis weight, be thin, and be wound tightly.

[0005] Incidentally, conventional toilet rolls, typically 25m long in 2-ply form or 50m long in 1-ply form, sometimes have patterns such as floral designs printed on them with ink (see Patent Document 2 below). These toilet rolls have superior design appeal. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2018-064664 [Patent Document 2] Japanese Patent Publication No. 2008-188070 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, in the case of a long-sized toilet roll, as described above, the toilet paper is made into a low rice mat, and in addition to reducing the paper thickness, it is necessary to make it a hard roll. Therefore, when printing a pattern, ink bleeding may occur, and unnecessary ink bleeding may occur on the back surface.

[0008]

[0009] Furthermore, in order to apply ink to the base paper with a thin paper thickness, the hardness of the ink-applied portion may be prominent, and it may be difficult to feel smoothness.

[0010] Furthermore, since the toilet roll has multiple layers of toilet paper stacked, in the case of a long-sized product, the pattern of the lower layer of toilet paper may be overly visible, and it may not achieve the desired design property due to the pattern.

[0011] Therefore, the main object of the present invention is to provide a toilet roll in which a design with excellent design property can be visually recognized and the smoothness of the surface can be easily felt in a long-sized toilet roll.

Means for Solving the Problems

[0012] The first means for solving the above problems is a toilet roll with a roll diameter of 90 to 120 mm formed by rolling 2-ply toilet paper, the 2-ply toilet paper is wound around a paper tube with a wound length of 65 to 90 m, Furthermore, the number of crepes is 35-50 per 10mm, Two sheets having concave portions on one side and convex portions on the other side formed by embossing are laminated such that their concave portion forming surfaces face outward, and have unevenness by double embossing of 2-ply, the embossing density is 3 to 25 pieces / cm 2 and a pattern is printed on the outer layer side of the toilet roll, and the pattern is only on the surface located on the outer layer, the porosity is 3 to 20%. A toilet roll characterized by the above.

[0013] The second means is A toilet roll according to the first means, having a roll density of 0.1 to 0.3.

Advantages of the Invention

[0014] According to the present invention as described above, there is provided a toilet roll which is a long product and yet has a design with excellent design properties that can be visually recognized, and further, a toilet roll in which the smoothness of the surface can be easily felt.

Brief Description of the Drawings

[0015] [Figure 1] A perspective view of a toilet roll according to an embodiment of the present invention. [Figure 2] A schematic diagram for explaining a measurement procedure of whiteness and color difference according to the present invention. [Figure 3] A diagram for explaining a pattern print according to the present invention. [Figure 4] A diagram for explaining an example of an emboss pattern according to the present invention.

Modes for Carrying Out the Invention

[0016] Next, the toilet roll according to the present invention will be described while referring to the drawings. As shown in FIG. 1, the toilet roll 1 according to the present invention is formed by winding a two-ply strip-shaped toilet paper 10 around a paper tube (also referred to as a tube core) 20 in a roll shape.

[0017] The roll diameter L2 of the toilet roll 1 according to the present invention is 90 to 120 mm, preferably 100 to 119 mm. The roll diameter L2 of a toilet roll is defined as 120 mm or less in JIS P 4501, and holders for setting general toilet rolls are manufactured based on this 120 mm standard. The toilet roll according to 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 Rule manufactured by Muratec KDS Co., Ltd. or an equivalent machine. The measured value is the average value of measurements taken at three different locations in the width direction. The roll width L1 of the toilet roll in this embodiment is not limited, but is preferably 100 to 130 mm. The outer diameter L3 of the paper core is also not limited, but is preferably 34 to 42 mm in diameter.

[0018] The toilet paper according to the present invention is characterized by having an embossed surface with a pattern formed by halftone printing and solid printing on one side, where the total area of ​​the pattern portion is 8-20%, the total area of ​​the halftone portion is 6.0% or more, and the total area of ​​the solid portion is 4.0% or less, and the thickness of each ply is 60-90 μm, and is wound on a 65-90 m paper core at a winding density of 0.83-2.05 with the side printed with the pattern facing the outer layer.

[0019] The toilet roll according to the present invention, having these configurations, is less prone to ink bleed-through when printing patterns and less prone to unnecessary ink bleeding on the reverse side. Furthermore, the halftone printing areas, solid printing areas, and the patterns of the toilet paper layer below are not excessively visible, allowing for a distinctive design. In addition, the hardness of the ink-applied areas is less noticeable, making it feel smoother.

[0020] The toilet roll according to the present invention has a paper thickness of 60 to 90 μm per ply of the wound toilet paper. Preferably, it is 60 to 85 μm. A paper thickness of 60 to 90 μm per ply allows for sufficient strength and softness as toilet paper, and makes it easy to achieve a winding diameter L2 (diameter) of 90 to 120 mm when winding a length of 65 to 90 m onto a paper core. Furthermore, under the pattern printing conditions of the present invention, it is possible to prevent ink bleed-through and unnecessary ink bleeding on the back side, and to reduce the occurrence of paper breakage during manufacturing.

[0021] The paper thickness shall be measured in a single-ply state using a dial thickness gauge (thickness measuring instrument) "PEACOCK G type" (manufactured by Ozaki Seisakusho Co., Ltd.) after the test piece has been humidified for at least 8 hours under the conditions of JIS P 8111 (1998). Specifically, after confirming that there is no dust or debris between the plunger and the measuring stand, the plunger is lowered onto the measuring stand, the scale on the dial thickness gauge is moved to set the zero point, then the plunger is raised and the sample is placed on the test stand, and the plunger is slowly lowered and the gauge reading is taken. During measurement, the plunger should only be rested on the test stand and not pressed down. The terminal of the plunger is made of metal and has a circular surface with a diameter of 10 mm that strikes perpendicular to the paper surface, and the load during this paper thickness measurement is approximately 70 gf. The paper thickness shall be the average value obtained by performing 10 measurements. The same measurement shall be performed even if the toilet paper has embossed irregularities. In this case, the measurement shall be performed so that one of the recesses is entirely within the range of the measuring stand. The crushing of uneven surfaces during measurement can be ignored. In this paper thickness measurement, the difference in paper thickness caused by the crushing of recesses can be ignored.

[0022] The toilet paper according to the present invention has a basis weight of 11.5 to 16.0 g / m². 2 It is desirable to keep it within this range. Preferably, 12.0 to 15.5 g / m 2 More preferably, 12.0 to 15.0 g / m². 2 It is 12.5~16.0 g / m³. 2Within this range, the winding density and void ratio of the toilet roll according to the present invention can be easily adjusted. Furthermore, in the toilet roll according to the present invention, the dry tensile strength and wet tensile strength can be appropriately adjusted by known methods within a range that does not hinder the effects of the present invention.

[0023] The toilet paper according to the present invention preferably has a ten-point average roughness [RzJIS] of 0.025 to 0.320 mm on the outer layer. More preferably, it is 0.025 to 0.315 mm. This range of ten-point average roughness [RzJIS] makes it less likely for printing to smudge, improves print clarity, and makes it easier to achieve excellent design. In particular, because the print clarity is good, the design does not deteriorate even when the ink application range is small, such as when the total area of ​​the pattern portion is 8 to 9.5% and the total area of ​​the halftone portion is 6.0 to 7.0%. The ten-point average roughness [RzJIS] is measured using a Keyence Corporation one-shot 3D measuring macroscope VR-3200 or an equivalent instrument and image analysis software "VR-H2A" or an equivalent software. The measurement is performed under conditions of 12x magnification and a field of view of 24 mm × 18 mm. However, the magnification and field of view can be adjusted as needed depending on the size of the embossing (recess). The ten-point average roughness [RzJIS] is measured by taking a 3D image and analyzing the data, avoiding the areas with ink applied to the design, and at any position if there is no embossing, or at a position that avoids the recesses caused by embossing, especially in the middle of adjacent recesses if the recesses are regularly arranged. The profile line measured in the line roughness measurement is measured and analyzed in the direction of the paper's flow. The measurement parameter is the "composite parameter RzJIS". Furthermore, for toilet rolls, the measurement point is an arbitrary position within the range of 29-31% from the outermost edge where the roll is first used, as the outermost surface reflects the smoothness of the toilet roll's surface but reduces accuracy. The measured value is the average of 10 points, and the measurement sample can be fixed to the measurement stand in a way that does not affect the measurement value.

[0024] Furthermore, the toilet paper according to the present invention preferably has a crepe count of 35 to 50 strands / 10 mm. Preferably, the crepe count is 35 to 50 strands / 10 mm, more preferably 37 to 48 strands / 10 mm, and more preferably 39 to 45 strands / 10 mm. This crepe count makes the surface feel smoother, and in particular, in the pattern printing according to the present invention described above, the hardness of the ink-applied areas becomes less noticeable, making the overall surface feel smoother. This crepe count can be adjusted by the crepe ratio during base paper manufacturing, the presence or absence of calendering, and the calendering pressure. The crepe count is measured using a Keyence Corporation one-shot 3D measuring macroscope VR-3200 or an equivalent, and image analysis software "VR-H2A" or an equivalent. The measurement is performed under conditions of a magnification of 12x and a field of view of 24 mm × 18 mm. However, the magnification and field of view can be appropriately changed depending on the size of the embossing (recess). The number of crepe strands is determined by taking a 3D image and analyzing the data, avoiding the areas with ink applied to the design, and measuring at any position if there is no embossing, or at a position that avoids the recesses caused by embossing, especially in the middle of adjacent recesses if the recesses are regularly arranged. The profile line to be measured for line roughness is specified to be perpendicular to the direction of paper flow, and the measurement and analysis are performed. The measurement parameter is "line roughness". The number of peaks in the obtained measurement cross-sectional curve over a measurement distance of 10 mm is defined as the number of crepe strands. Furthermore, for toilet rolls, the measurement location is an arbitrary position within the range of 29-31% from the outermost edge where the toilet roll is first used, as the outermost surface reflects the smoothness of the toilet roll's surface but reduces accuracy. The measurement value is the average of 10 points, and the measurement sample can be fixed to the measurement stand in a way that does not affect the measurement value.

[0025] The toilet roll according to the present invention has a pattern printed on one side of the toilet paper, and is wound onto a paper tube with the printed side facing the outer layer. In other words, the toilet roll according to the present invention has a pattern only on the side that is located on the outer layer. Printing the pattern on the outer layer allows the pattern to be directly seen from the outside, and in particular, even if the pattern is printed faintly, such as with halftone printing, it becomes easier to see clearly.

[0026] Furthermore, because toilet paper is made up of multiple layers, if the pattern of one or more layers below shows through, there is a risk that the pattern of the lower layer and the pattern of the outer layer will be mixed together and visible. However, since the toilet paper of the present invention is 2-ply, there is an unprinted layer in the inner layer of ply. Therefore, if the pattern is formed only on the outer layer within the paper thickness range defined in the present invention, the pattern of the outer layer will be clearly visible, while the pattern of the lower layer will be difficult to see. Moreover, this is even more true with the above basis weight. To ensure that the pattern is only on the outer layer, the toilet paper should be wound so that the printed side faces outwards.

[0027] The patterns according to the present invention are formed by printing and do not include those colored during the papermaking stage by supplying dyes to the papermaking raw materials. The specific design of the patterns is not particularly limited. For example, examples include patterns in which one or more types are appropriately selected and depicted from among plants such as flowers, trees, and grass; living things such as people, animals, fish, shells, and insects; nature such as mountains, rivers, seas, clouds, forests, and woods; planets and satellites such as the moon, sun, and stars; and man-made objects such as cars, airplanes, and trains. The area of ​​a single pattern is not particularly limited, but is 102 mm². 2 ~918mm 2 If done to this extent, the design will be easy to see and perceived as aesthetically pleasing, while the amount of ink in each design area will not be excessively large, making bleed-through less likely.

[0028] The pattern according to the present invention is formed by halftone printing and solid printing. The total area ratio of the pattern portion is 8 to 20%, preferably 8 to 10%. This pattern portion is the sum of the halftone portion and the solid portion. The total area ratio refers to the ratio of the pattern portion to the area of ​​one side of the toilet paper. Since the pattern on printed toilet paper is repeated at a predetermined pitch due to the manufacturing process, the method for calculating the total area ratio of the pattern portion is to cut 10 sheets of toilet paper in 50cm increments from the tip excluding the tail seal portion, calculate the ratio of the area of ​​the pattern portion to the area of ​​one side of each sheet (width of the toilet paper × 50cm), and use the average value of the 10 sheets. The area of ​​the pattern portion in the sample can be measured by optically scanning the sample and measuring it with known software.

[0029] If the total area of ​​the patterned portion accounts for 8-20%, the toilet paper will not feel stiff due to the application of ink during use, and wrinkles and creases will not occur during manufacturing, especially when using the tension required for other roll configurations according to the present invention, such as roll length and roll diameter. Although halftone printing is microscopically composed of ink-applied and non-ink-applied portions, the halftone portion in this invention refers to the entire area that is recognized as a single pattern by halftone printing, including not only the ink-applied portions but also the non-ink-applied portions. The ratio of halftone portions to solid areas in a single pattern is preferably 60:40-90:10, and particularly preferably 65:35-85:15.

[0030] The shape of each halftone dot in the halftone printing method according to the present invention is not particularly limited. For example, it can be a rhombus, square, rectangle, circle, ellipse, polygon, star, etc.

[0031] Furthermore, the toilet paper according to the present invention has a total area ratio of 6.0% or more for the halftone portion and a total area ratio of 4.0% or less for the solid area portion. By setting the total area ratio of the halftone portion to 6.0% or more and the total area ratio of the solid area portion to 4.0% or less, ink bleed-through due to application is less likely without severely reducing the recognizability of the design, and the design quality can be ensured. In addition, the toilet paper as a whole does not become rigid, and wrinkles and creases that occur during the above manufacturing process are less likely to occur. Furthermore, in combination with the other configurations of the present invention, when formed into a toilet roll, the solid area is not excessively recognized through the non-designed portion of the toilet paper on the outer surface, resulting in a toilet roll that is easily recognized as having the intended design.

[0032] Furthermore, the ratio of the total area of ​​the halftone portion and the total area of ​​the solid portion are calculated in the same way as the ratio of the total area of ​​the pattern portion. Ten sheets of toilet paper are cut from the tip, excluding the tail seal, in 50cm increments, and the ratio of the total area of ​​the halftone portion and the solid portion to the area of ​​one side of each sheet (width of the toilet paper × 50cm) is calculated and the average of the ten sheets is used. The area of ​​the halftone portion and the solid portion in the sample can also be measured by optically scanning the sample and measuring it using known software.

[0033] In this invention, the dot area ratio in the dot area is 20-60%, particularly preferably 30-50%. The dot area ratio is the proportion of the dot area where ink is actually applied. If the dot area ratio is less than 20%, the clarity of the design will be poor, and if the dot area ratio exceeds 60%, it will approach solid printing, the faintness of the design due to dot printing will be lost, the design quality will decrease, and the design area will tend to become rigid. In addition, especially when using water-based ink, the moisture will cause the paper to shrink, and wrinkles and creases are likely to occur in the paper at the total area ratio of the design according to this invention.

[0034] The pattern on the toilet paper according to the present invention is preferably printed by flexographic printing (relief printing) using aqueous ink. However, intaglio printing such as gravure printing, and lithographic printing such as offset printing can also be employed. In particular, for aqueous ink, if the viscosity is 10 to 50 cps, the vehicle is 30 to 60% by mass, and the water content is 70 to 40% by mass, the clarity of the pattern can be made sufficient, and even if water penetrates into the paper, wrinkles and creases are less likely to occur. The viscosity is the value measured by a B-type viscometer.

[0035] When printing the pattern according to the present invention, regardless of the halftone part and the solid part, the line count of the anilox roll used is not necessarily limited, but 250 to 600 / inch, more preferably 250 to 500 / inch is desirable. It is suitable for forming the pattern according to the present invention.

[0036] The toilet roll according to the present invention has toilet paper having the above-mentioned pattern wound around a paper tube with a winding density of 0.83 to 2.05 m / cm 2 , and a winding length of 65 to 90 m. The winding length of 65 to 90 m of the toilet paper is more than twice as long as that of a conventional popular product for general households, which is about 25 m for 2-ply. The winding length is measured while unwinding the toilet roll without applying tension. For example, it may be measured while folding it back in a zigzag pattern by 5 m at a time from the unwinding.

[0037] And the toilet roll according to the present invention has the above-mentioned winding length and a winding density of 0.83 to 2.05 m / cm 2 Preferably, it is 0.95 to 1.45 m / cm 2 More preferably, it is 1.00 to 1.30 m / cm 2The winding density according to this invention is a value calculated by multiplying 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) × (winding diameter / 2) × π - (paper tube outer diameter / 2) × (paper tube outer diameter / 2) × π. In other words, it is the area obtained by subtracting the area of ​​the paper tube opening end from the area of ​​the end face. In the case of the above winding length, the winding density is particularly 0.83 to 2.05 m / cm². 2 Materials within this range are easy to manufacture and have very few wrinkles or creases. Furthermore, when holding the roll by its circumference, it feels appropriately firm, giving a sense of a substantial length, while avoiding excessive softness or a stiff feel. 2.05 m / cm 2 Beyond this point, it tends to feel stiffer than its actual length. On the other hand, 0.83 m / cm 2 If the length is less than this, the roll may feel excessively soft relative to its length, making it difficult to achieve a firm feel.

[0038] The toilet roll according to the present invention has the above winding density and a roll density of 0.10 to 0.30 g / cm³. 3 It is desirable that this be the case. More preferably, 0.10 to 0.25 g / cm³. 3 The roll density is expressed as (roll mass) ÷ (roll volume). The roll mass is the mass of the toilet roll per 114 mm roll width. The roll volume is expressed as [{cross-sectional area of ​​the roll's winding diameter L1 portion} - (cross-sectional area of ​​the paper core's outer diameter L3 portion)] × roll width (converted to 114 mm). Roll density is also an indicator of how densely and tightly the toilet roll is wound, or how loosely it is wound. If it is too loose, it is prone to excessive deformation, such as the paper core popping out, and if it is too hard, the toilet paper will feel hard when you hold the toilet roll.

[0039] Furthermore, in the toilet roll according to the present invention, the proportion of the total area of ​​the patterned portion is set to 8-20%, the proportion of the total area of ​​the halftone portion is set to 6.0% or more, and the proportion of the total area of ​​the solid color portion is set to 4.0% or less. This allows the pattern to be clearly recognizable, prevents bleed-through, and minimizes wrinkles and creases. In other words, when increasing the length of the roll and the winding density, it is necessary to increase the tension when winding the toilet paper onto the paper tube to form the toilet roll. In toilet paper with a pattern, the stretch of the paper differs between the printed portion where ink is applied and the non-printed portion where ink is applied. Therefore, increasing the tension makes the toilet paper prone to wrinkles and creases when it becomes a toilet roll, but this problem is solved in the toilet roll according to the present invention. In other words, the present invention provides a toilet roll that is particularly easy to recognize the pattern, does not bleed through, feels sufficiently soft when held in the hand, and is free from wrinkles and creases.

[0040] Furthermore, it is desirable that the toilet roll according to the present invention has a porosity of 3 to 20%. The porosity (%) according to the present invention is the value calculated by (actual porosity of the entire roll) / (theoretical roll volume) × 100. The actual porosity of the entire roll is (actual cross-sectional area (cm²) 2 The theoretical roll volume is calculated as ((theoretical roll volume (cm)) × (roll width (cm)) and the theoretical roll volume is calculated as (roll length (cm) × 2 × paper thickness (1 ply, cm)) × (roll width (cm)). The void ratio (actual void ratio of the entire roll, %) is calculated as ((theoretical roll volume (cm) 3 ))-(Actual roll volume (cm³) 3 ))) / (Theoretical roll volume (cm 3 It is calculated as )) × 100(%). The roll width L1 should be approximately 100-130 mm. The void ratio is an indicator of how much space exists within a toilet roll, and it shows the degree to which the paper is tightly wound. This indicator is adjusted by the embossing, paper thickness, and winding stiffness. When the paper is thick, the void ratio is high, which can be due to excessively deep and hard embossing that is difficult to crush, or because the paper layer itself is thick, and in either case it may feel hard. According to the present invention, when the void ratio is high, the roll tends to feel hard, and when the void ratio is low, the roll tends to feel soft. Furthermore, when the void ratio exceeds 20%, the print may bleed through to the other side, making it difficult to see the design on the roll, and when it falls below 3%, the print may appear blurry due to printing smudges.

[0041] Furthermore, the toilet paper according to the present invention has a whiteness of 80% or more in the areas without pattern printing, and the color difference ΔE = ((ΔL)) between the Lab value measured directly in the patterned area of ​​the lower layer and the Lab value measured by passing the patterned area through the white area of ​​the upper layer of toilet paper without pattern printing. 2 +(Δa) 2 +(Δb) 2 ) 1 / 2 However, it is desirable that it be in the range of 2.20 or less. More preferably, it is less than 2.00. Furthermore, it is desirable that the color difference ΔE' between the Lab value measured through the unprinted white portion of the upper layer of toilet paper and the Lab value of the unprinted white portion of the upper layer of toilet paper be 6.0 or less. With these whiteness levels, ΔE and ΔE', as shown in Figure 3, the pattern 40 of the lower layer, visible through the unprinted white areas of the upper layer of toilet paper, is not excessively clear or visible, but rather vaguely and faintly visible. At the same time, the pattern composed of the directly visible solid areas 41 and halftone areas 42 of the upper layer becomes clearly visible. As a result, the contrast between the directly visible patterns 41 and 42 and the lower layer pattern 40 visible through the white areas of the toilet paper creates a unique and distinctive design. In particular, when the pattern printing is 8-20%, the pattern area is not excessively wide, and the effect of the contrast between the directly visible printed areas, the white areas, and the printed areas visible through the upper layer is pleasantly noticeable.

[0042] Herein, the procedure for measuring whiteness and color difference ΔE, ΔE' according to the present invention is as shown in Figure 2: Five sheets of white cardboard 31 are stacked on a horizontal measuring table, and the sample 33 to be measured is placed on top of them. Furthermore, a piece of toilet paper 34 taken from the same toilet roll as the sample 33 is placed on top of the sample 33, with the part without a pattern covering the patterned portion 32 to be measured. Finally, a piece of white cardboard 35 with a φ20 mm window cutout 36 is placed on top of that, so that the patterned portion 32 to be measured is located within the window cutout 36.

[0043] Then, the whiteness and Lab value (the Lab value measured through the unprinted white portion of the upper layer of toilet paper) of the pattern to be measured are measured using a spectrophotometer through the toilet paper 34 at the window cutout 36. Next, the toilet paper 34 stacked on top of the sample 32 is removed so as not to move the measurement point, and the whiteness and Lab value (the Lab value measured directly through the unprinted portion of the lower layer of toilet paper) of the pattern to be measured are measured using a spectrophotometer. Next, the sample is removed again, and the whiteness and Lab value (the Lab value of the unprinted white portion of the upper layer of toilet paper) of the top layer of the five stacked white cardboard 31 are measured using a spectrophotometer (blank value). The spectrophotometer used is a PF7000 spectrophotometer / colorimeter manufactured by Nippon Denshoku Industries Ltd. or an equivalent instrument. The color differences ΔE and ΔE' are calculated from the measured Lab values.

[0044] The number of colors that make up the pattern applied to the toilet paper according to the present invention is not limited, but from the viewpoint of cost, equipment, and because toilet paper is low density and prone to bleeding, it is desirable to use 1 to 3 colors. In addition, the solid areas and halftone areas may have different colors. When measuring the Lab value of the above pattern, if there are multiple colors in a single pattern, it is desirable to measure all of the parts with different colors and ensure that all measured values ​​fall within the above numerical range.

[0045] The fibers in the toilet paper according to the present invention are not limited, but preferably consist of 70-100% virgin pulp and 0-30% recycled paper pulp. Adding recycled paper pulp allows for cheaper production compared to toilet paper made from 100% virgin pulp. Furthermore, recycled paper pulp tends to have finer fibers than the pulp fibers before recycling during the pulp regeneration process. Due to these fiber properties, the paper strength is easily increased without increasing the paper thickness, resulting in denser fibers. On the other hand, excessive addition reduces flexibility and other textures. Therefore, considering the characteristics of recycled paper pulp, its blending ratio should be determined within the range of 0-30% by mass. While the type of recycled paper pulp is not necessarily limited, recycled paper pulp made from recycled milk cartons and high-quality recycled paper is particularly desirable. These contain a large amount of coniferous kraft pulp (NBKP) derived from the raw materials, making them more likely to exhibit paper strength.

[0046] The pulp used should preferably be softwood kraft pulp (NBKP) and hardwood kraft pulp (LBKP). The ideal mixing ratio of NBKP to LBKP is 20:80 to 50:50. NBKP can also be derived from recycled milk cartons. Toilet paper manufactured using a fiber material consisting of virgin pulp and the above-mentioned high-quality recycled paper pulp should have a recycled paper-derived mechanical pulp content of 5% or less by mass, an ash content of 3% or less by mass, and a whiteness of approximately 80-85%.

[0047] The toilet roll according to the present invention has an embossed surface. When toilet paper is embossed, the toilet paper itself becomes softer, and the uneven surface improves its ability to wipe away feces. In addition, because the embossed surface of the toilet paper has an uneven surface, it becomes difficult to see the pattern of the underlying layer through the paper, resulting in a superior design.

[0048] The toilet paper according to the present invention may be a double-embossed toilet paper in which each ply is given an embossed surface and laminated into two plies. Preferably, it is a double-embossed toilet paper. Double-embossed toilet paper is more suitable for achieving the winding density and stiffness according to the present invention. Furthermore, among double-embossed toilet paper, it is preferable to have a 2-ply double-embossed toilet paper in which two sheets, each with a recessed surface on one side and a raised surface on the other, are laminated so that the recessed surfaces face outwards. This makes it easier to create gaps between the plies, making it more difficult to see the pattern of the lower layer through the paper surface, resulting in superior design. In particular, for this double-embossed toilet paper, the basis weight should be 11.5 to 15.0 g / m². 2 It is preferable to keep it within this range. More preferably, 11.5 to 14.0 g / m². 2 That is the case.

[0049] The specific patterns of the raised and recessed areas created by embossing are not necessarily limited. The embossed patterns can be any appropriate pattern, such as micro-embossing, dot embossing, or design embossing. However, it is desirable that the raised and recessed areas created by the embossing are arranged in a way that does not impair the visibility of the printed design. For example, a pattern in which the recessed areas are simply arranged regularly, so as to be perceived as a separate background unrelated to the design, is desirable. More specifically, patterns in which squares, triangles, polygons, circles, ellipses, or square-shaped stars (extended squares) are arranged regularly in a vertical and horizontal direction are desirable. Such patterns can be designed so that the design created by the raised and recessed areas of the embossing and the design of the printed design do not interfere with each other, but rather create a synergistic design effect.

[0050] A particularly preferred pattern for embossed recesses (recesses) is, as shown in Figure 4, a pattern in which square recesses 41 (Figure 4A) with a base of diagonal L5 × diagonal L5 = 1.0~1.5 × 1.0~1.5 mm, or recesses 51 that form a roughly square shape with the four corners of the square extending outward from the diagonal (Figure 4B), are arranged in a grid pattern with a center spacing L6 of 4.5~5.5 mm and an arrangement angle of 45° with respect to the width direction, and valley lines 53 extending from the four corners of the recesses between the recesses 51. It is desirable that the valley lines 53 are arranged in a gradually curving cross-section such that the four corners of the recesses 51 are the deepest and the middle of the recesses is the shallowest. This embossed pattern does not reduce the design quality of the printed image and is also likely to be superior in terms of softness, flexibility, and ease of wiping away feces. Furthermore, the valley lines 53 directed at a 45° angle in the width direction distribute the tension during winding, resulting in extremely clear embossed irregularities in the winding length of the toilet roll according to the present invention, and making it less likely for wrinkles to occur.

[0051] Here, the preferred embossing density according to the present invention is 3 to 25 embossings / cm². 2 Preferably, 4 to 20 pieces / cm 2 It is 3-25 pieces / cm 2 With this embossing density, the synergy between the design created by embossing and the design created by printing according to the present invention makes it less likely for the printed pattern to look cheap, even if the total area of ​​the pattern portion is less than 10% and the total area of ​​the halftone portion is 6.0%, and the improvement in design quality is easily perceived. Embossing density is measured using a Keyence VR-3200 one-shot 3D measuring macroscope or an equivalent instrument, and image analysis software "VR-H2A" or an equivalent software. Measurements are taken under conditions of 12x magnification and a field of view of 24mm x 18mm. The area of ​​a region containing multiple embossed units that constitute the embossing pattern is measured, and the number of embossed units in that region is counted. "Region containing multiple embossed units" refers to the smallest unit, or multiple times the smallest unit, that can constitute the entire embossing pattern dividing the toilet paper surface into equal areas. Embossing density (units / mm²) 2 The magnification and field of view area are calculated as follows: (Number of embossed areas in the area including multiple embossed units) ÷ (Area of ​​the area including multiple embossed units). However, the magnification and field of view area can be appropriately changed depending on the size of the embossing (recesses). [Examples]

[0052] Next, the "smoothness of the sheet," "smoothness of the roll surface," "resistance to showing through to the other side," and "print clarity (absence of print smudging)" of the toilet rolls of the present invention were confirmed for the examples and comparative examples. The composition of the toilet rolls and the physical properties and composition of the toilet paper for each example, as well as the test results, are shown in Table 1 below. The examples and comparative examples consist of two sheets of double-embossed toilet paper, each with a recessed surface on one side and a raised surface on the other, which are laminated together so that the recessed surfaces face outwards. The embossing pattern in each example is the arrangement of the recesses shown in Figure 4(B).

[0053] The smoothness of the toilet paper sheets was evaluated by taking two sections of toilet paper from a toilet roll, with one section being the space between adjacent perforations. Participants were then asked to touch these two sections of toilet paper and rate the smoothness of the sheet surface on a scale of 1 to 5. The evaluation criteria were as follows: 5 for "satisfied," 4 for "somewhat satisfied," 3 for "neither satisfied nor dissatisfied," 2 for "somewhat dissatisfied," and 1 for "dissatisfied." The values ​​in Table 1 are average values ​​rounded to a single decimal place. The number of participants was 30.

[0054] The smoothness of the toilet roll surface was evaluated by having subjects actually touch the outer surface of the toilet roll and rate it on a scale of 1 to 5. The evaluation criteria for smoothness were as follows: 5 for "satisfied," 4 for "somewhat satisfied," 3 for "neither satisfied nor dissatisfied," 2 for "somewhat dissatisfied," and 1 for "dissatisfied." The values ​​in Table 1 are average values ​​rounded to a single digit. The number of subjects was 30.

[0055] The ability to prevent ink bleeding through was evaluated by having subjects visually observe the back side (non-printed area) of the toilet paper corresponding to the printed area on the outer edge. The evaluation criteria were as follows: 5 for "no bleeding at all," 4 for "no bleeding," 3 for "neither," 2 for "some bleeding," and 1 for "bleed-through." The values ​​in Table 1 are average values ​​rounded to a single digit. The number of subjects was 30.

[0056] Print clarity was evaluated by having subjects visually observe the printed area on the outer surface of the toilet roll and assigning a score to the following criteria: 5 for "clear with no smudging," 4 for "slightly smudging but generally clear," 3 for "some smudging but generally clear," 2 for "some smudging and slightly unclear," and 1 for "overall smudging and unclear." The values ​​in Table 1 are average values ​​rounded to a single digit. The number of subjects was 30.

[0057] [Table 1]

[0058] Examples 1 to 7 use thin paper to achieve a longer length, but by using halftone printing, they achieve sufficient design quality with a total design area of ​​8% or more, while also preventing bleed-through. In contrast, Comparative Examples 1, 3, and 4 have a total design area ratio within the scope of the present invention, but the entire design is printed in solid color. In these examples, bleed-through was observed.

[0059] Comparative Example 2 consists of halftone areas and solid areas, but the proportion of the total area of ​​the solid areas is higher than in the present invention. In Comparative Example 2, bleed-through was also confirmed.

[0060]

[0061] Furthermore, when examining print clarity in particular, double embossing yielded better results when the 10-point average roughness (RzJIS) was within the range of the present invention.

[0062] As described above, the toilet roll according to the present invention is easy to manufacture even when extended in length, allows for the visibility of aesthetically pleasing patterns, and provides a smooth surface that is easy to perceive. [Explanation of Symbols]

[0063] 1...Toilet roll, 10...Toilet paper, 20...Paper tube (core), L1...Toilet roll winding diameter, L2...Toilet roll core diameter, L3...Toilet roll width, 51...Recess, 53...Valley line section, 40...Lower layer design, 41...Upper layer solid area, 42...Upper layer halftone area.

Claims

1. A toilet roll made of 2-ply toilet paper with a roll diameter of 90 to 120 mm, The aforementioned two-ply toilet paper is wound onto a paper tube in a length of 65 to 90 meters. Furthermore, the number of crepes is 35 to 50 per 10 mm. Two sheets, each with a recessed surface on one side and a raised surface on the other due to embossing, are laminated together so that the recessed surfaces face outwards, resulting in a two-ply double-embossed surface. Embossing density: 3-25 embossings / cm² ２ And, The toilet roll has a design printed on its outer layer, and the design is present only on the surface located on the outer layer. The porosity is 3-20%. A toilet roll characterized by the following features.

2. The toilet roll according to claim 1, wherein the roll density is 0.1 to 0.

3.

3. The toilet roll according to claim 1 or 2, wherein the winding density is 0.83 to 2.05.

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