Paper towel roll

Abstract

This invention provides a paper towel roll that, even when an embossed pattern is applied to a paper towel sheet obtained using TAD papermaking technology and wound into 2-3 plies using glue, exhibits good aesthetic appeal of the embossed pattern, produces less glue residue, and is less prone to ply separation. [Solution] This disclosure relates to a paper towel roll 1 obtained by laminating a paper towel sheet 1x, in which at least one ply has an embossed pattern applied to it, with glue, into 2 to 3 plies, and winding the resulting roll, wherein the number of short embossed patterns with a longest portion of 20 mm or less is greater than the number of long embossed patterns with a longest portion exceeding 20 mm, and the basis weight of the paper towel sheet 1x in the product ply is 30 g / m². 2 More than 56g / m 2 The following is the water absorption capacity per unit area of ​​one sheet of product ply paper towels: 300 g / m² 2 More than 600g / m 2 The following applies:

Description

Technical Field

[0001] The present disclosure relates to a paper towel roll.

Background Art

[0002] A paper towel sheet obtained by a so-called TAD (Through Air Dryer, Through Air Drying) papermaking technique using through-air drying is thick, has a soft texture, and is excellent in water absorption.

[0003] As a technique related to a papermaking technique using through-air drying, Patent Document 1 discloses a non-creped through-air dried tissue sheet having protrusions of about 10 to about 150 per 6.45 square centimeters (1 square inch) having a height of about 0.012 millimeters (0.005 inches) or more, an elongation rate in the machine transverse direction of about 9 percent or more, and a basis weight of about 10 to 70 grams per square meter.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the paper towel sheet obtained by the TAD papermaking technique has irregularities, even if an embossing pattern is provided, it is difficult to make it stand out, and it is difficult to ensure the decorative property by the embossing pattern. In order to ensure the decorative property by the embossing pattern in the paper towel sheet obtained by the TAD papermaking technique, it is conceivable to provide a long linear embossing pattern.

[0006] Incidentally, while paper towel sheets obtained using TAD papermaking technology have excellent water absorption, the sheets have an uneven surface. Therefore, when using plybond glue (glue) to create 2-3 plies, the adhesion between the plies weakens, making them prone to peeling. Increasing the amount of glue improves ply adhesion, but it also increases the likelihood of strike-through. When strike-through occurs, a mixture of glue and paper dust (hereinafter referred to as "glue residue") accumulates on the raised parts of the embossing roll (the parts that become the embossed pattern). If this glue residue accumulated on the raised parts of the embossing roll adheres to the product, it results in a defective product.

[0007] Reducing the size of the embossing pattern can suppress glue residue, but it becomes difficult to maintain the aesthetic appeal achieved through the embossing pattern. Furthermore, paper towel sheets produced using TAD papermaking technology have high water absorption, which can lead to ply separation due to excessive water absorption.

[0008] Therefore, the present disclosure aims to provide a paper towel roll in which an embossed pattern is applied to a paper towel sheet obtained using TAD papermaking technology, and even when wound up in 2-3 plies using glue, the embossed pattern maintains good aesthetic appeal, the amount of glue residue is small, and the plies are less prone to peeling. [Means for solving the problem]

[0009] To solve the above problems, a first aspect of the present invention is a paper towel roll obtained by laminating a sheet with an embossed pattern on at least one ply with glue, and stacking the resulting sheet into 2 to 3 plies, wherein the number of short embossed patterns with a longest portion of 20 mm or less is greater than the number of long embossed patterns with a longest portion exceeding 20 mm, and the basis weight of the paper towel sheet in the product ply is 30 g / m². 2 More than 56g / m 2 The following is true: the water absorption capacity per unit area of ​​the product ply paper towel sheet is 300 g / m². 2 More than 600g / m 2The following applies:

[0010] A second aspect of the present invention is a paper towel roll according to the first aspect, wherein the paper thickness of the product ply paper towel sheet is 0.4 mm or more and 0.8 mm or less.

[0011] A third aspect of the present invention is a paper towel roll according to the first or second aspect, wherein the ply peel strength of the paper towel sheet is 8 cN / 76 mm or more and 50 cN / 76 mm or less.

[0012] A fourth aspect of the present invention is a paper towel roll according to the first or second aspect, wherein the number of short embossed areas per unit area is 10 / 100cm². 2 More than 500 pieces / 100cm 2 That is the case.

[0013] A fifth aspect of the present invention is a paper towel roll according to the first or second aspect, wherein the root mean square height of the surface roughness on the back surface of the product ply paper towel sheet is 38 μm or more and 125 μm or less.

[0014] A sixth aspect of the present invention is a paper towel roll according to the first or second aspect, wherein the water absorption per unit weight of the paper towel sheet in the product ply is 7 g / g or more and 15 g / g or less.

[0015] A seventh aspect of the present invention is a paper towel roll according to the first or second aspect, wherein the paper towel sheet contains wet pulp, and the weight content of the wet pulp is 60% or more and 100% or less. [Effects of the Invention]

[0016] According to this disclosure, even when an embossed pattern is applied to a paper towel sheet obtained using TAD papermaking technology and wound into 2-3 plies using glue, it is possible to provide a paper towel roll that has good aesthetic appeal of the embossed pattern, produces less glue residue, and is less prone to ply peeling. [Brief explanation of the drawing]

[0017] [Figure 1] This is a perspective view of a paper towel roll according to one embodiment of the present invention. [Figure 2] This is an explanatory diagram of a method for measuring the water absorption capacity of paper towel sheets. [Figure 3] This figure shows an example of an embossed pattern. [Figure 4] This figure shows examples of radial embossing and closed-ring structure embossing patterns. [Figure 5] This figure shows the height profile on the XY plane as measured by a microscope, indicated by varying shades of gray. [Figure 6] This figure shows the height profile on the XY plane as measured by a microscope. [Figure 7] This diagram shows how to determine the depth of an embossed pattern. [Figure 8] This diagram shows the height profile of the back surface of a paper towel sheet on the XY plane, as measured by a microscope, using shades of gray. [Figure 9] This is an explanatory diagram of the longest part of the embossing. [Figure 10] This diagram shows a part of the papermaking process for paper towel rolls. [Modes for carrying out the invention]

[0018] An embodiment of the present invention will be described below with reference to the drawings. In the following description, the MD direction in a paper towel sheet refers to the flow direction (Machine Direction) when the paper towel sheet is made, and the CD direction refers to the direction perpendicular to the MD direction (Cross Direction). Also, in the following description, a paper towel roll may be simply referred to as a "roll".

[0019] <Paper towel roll> Figure 1 is a perspective view of a paper towel roll according to one embodiment of the present invention.

[0020] As shown in Figure 1, the paper towel roll 1 according to this embodiment is a paper towel roll 1 in which a sheet with an embossed pattern on at least one ply is bonded with glue, and the resulting laminated paper towel sheet 1x is wound into a roll. In this embodiment, the paper towel sheet 1x is wound around a core 1d. Preferably, the paper towel sheet 1x has perforations 1c in the roll width direction (axial direction) at approximately equal intervals in the roll winding direction (circumferential direction).

[0021] As shown in Figure 1, the radially outer surface of the paper towel roll 1 is referred to as the surface 1a (surface of the paper towel sheet 1x), and the radially inner surface is referred to as the back surface 1b (back surface of the paper towel sheet 1x).

[0022] Uses of paper towel roll 1 include, for example, rolls of kitchen paper (sometimes called kitchen towels, cooking paper, etc.) used in home kitchens and restaurant kitchens for wiping up moisture or oil and removing dirt, as well as rolls of other sanitary paper.

[0023] (winding diameter) The roll diameter DR of the paper towel roll 1 is preferably 127 mm or more and 180 mm or less. If the roll diameter DR of the paper towel roll 1 is less than 127 mm, the basis weight will be lower in order to achieve the desired roll length, resulting in poor water absorption. On the other hand, if the roll diameter DR of the paper towel roll 1 is larger than 180 mm, the basis weight will be higher in order to achieve the desired roll length, and if a certain amount of glue is applied to bond the sheets, the amount of glue will not be sufficient for bonding, resulting in weak peel strength and easy ply separation (sheets peeling off from each other). The lower limit of the above range for the roll diameter DR of the paper towel roll 1 is more preferably 135 mm or more, and even more preferably 140 mm or more. The upper limit of the above range for the roll diameter DR of the paper towel roll 1 is more preferably 170 mm or less, and even more preferably 157 mm or less.

[0024] The winding diameter DR of paper towel roll 1 is measured using a diameter rule manufactured by Muratec KDS Co., Ltd. Three paper towel rolls 1 are measured, and the measurement results are averaged.

[0025] (Length of volume) The length of the paper towel roll 1 is preferably between 18m and 45m. If the length of the paper towel roll 1 is shorter than 18m, the basis weight will have to be high in order to achieve the desired roll diameter DR, making it prone to ply delamination. On the other hand, if the length of the paper towel roll 1 is longer than 45m, the basis weight will have to be low in order to achieve the desired roll diameter DR, resulting in poor water absorption. The lower limit of the length of the paper towel roll 1 within the above range is more preferably 20m or more, and even more preferably 24m or more. The upper limit of the length of the paper towel roll 1 within the above range is more preferably 40m or less, and even more preferably 35m or less.

[0026] The length of a paper towel roll 1 is measured as follows: First, measure the length of 10 sheets of paper towels 1x between perforations 1c on the paper towel roll 1. Then, measure the number of sheets in the paper towel roll 1, and calculate the length proportionally from the length of 10 sheets and the number of sheets. For example, if the length of 10 sheets is 1.80m and the number of sheets is 150, then 1.80m × (150 / 10) = 27m. If the paper towel roll 1 does not have perforations 1c, measure the length directly.

[0027] (Roll width) The roll width W of the paper towel roll 1 is preferably between 150 mm and 380 mm. If the roll width W of the paper towel roll 1 is less than 150 mm, the amount of water absorbed by each paper towel sheet 1x will decrease. On the other hand, if the roll width W of the paper towel roll 1 is greater than 380 mm, the amount of water absorbed by each paper towel sheet 1x will be excessively high. The lower limit of the roll width W of the paper towel roll 1 is more preferably 200 mm or more, and even more preferably 250 mm or more. The upper limit of the roll width W of the paper towel roll 1 is more preferably 340 mm or less, and even more preferably 300 mm or less.

[0028] (core) The core 1d is a core located in the center of the paper towel roll 1, and is preferably a cylindrical paper tube that winds the paper towel sheets 1x into a roll.

[0029] The core 1d is preferably a paper tube containing BKP (Bleached Kraft Pulp), which is at least one of NBKP (Coniferous Kraft Pulp) and LBKP (Broadleaf Kraft Pulp). The BKP content is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. Of the BKP, the LBKP content is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. This range makes it easier to wrap a paper towel sheet 1x, such as in the present invention, around the core 1d.

[0030] (Core outer diameter) The outer diameter of core 1d (hereinafter referred to as "core outer diameter DI") is preferably 28 mm or more and 58 mm or less. If the core outer diameter DI is smaller than 28 mm, the basis weight will be high in order to achieve the desired winding diameter DR, making the ply more prone to delamination. On the other hand, if the core outer diameter DI is larger than 58 mm, the basis weight will be low in order to achieve the desired winding diameter DR, resulting in poor water absorption. The lower limit of the above range for core outer diameter DI is more preferably 33 mm or more, and even more preferably 40 mm or more. The upper limit of the above range for core outer diameter DI is more preferably 53 mm or less, and even more preferably 46 mm or less.

[0031] The core outer diameter DI is measured using a Diameter Rule manufactured by Muratec KDS Corporation. The measurement is performed by measuring three paper towel rolls and averaging the results.

[0032] (Core mass) The mass of core 1d per 280 mm roll width (hereinafter referred to as "core mass") is preferably 10 g or more and 25 g or less. If the core mass is less than 10 g, the core outer diameter DI becomes smaller when the basis weight of core 1d is within a certain range, and in order to achieve the desired winding diameter DR, the basis weight becomes higher, making the ply more prone to delamination. On the other hand, if the core mass is greater than 25 g, the core outer diameter DI becomes larger when the basis weight of core 1d is within a certain range, and in order to achieve the desired winding diameter DR, the basis weight becomes lower, resulting in poor water absorption. The lower limit of the above range for core mass is more preferably 12 g or more, and even more preferably 13 g or more. The upper limit of the above range for core mass is more preferably 21 g or less, and even more preferably 17 g or less.

[0033] (Roll mass <coreless>) The roll mass of paper towel roll 1, excluding the core 1d per 280 mm of roll width (hereinafter also simply referred to as "roll mass <core-free>"), is preferably 215 g or more and 540 g or less. If the roll mass <core-free> is less than 215 g, the basis weight will be low in order to achieve the desired roll length, resulting in poor water absorption. On the other hand, if the roll mass <core-free> is greater than 540 g, the basis weight will be high in order to achieve the desired roll length, making the ply more prone to peeling. The lower limit of the above range for the roll mass <core-free> of paper towel roll 1 is more preferably 250 g or more, and even more preferably 280 g or more. The upper limit of the above range for the roll mass <core-free> of paper towel roll 1 is more preferably 480 g or less, and even more preferably 445 g or less. If the roll width W of paper towel roll 1 is not 280 mm, the mass per 280 mm is converted by proportional calculation.

[0034] (Roll mass <with core>) The roll mass including the core 1d per roll width of 280 mm of the paper towel roll 1 (hereinafter, also simply referred to as "roll mass <with core>") is preferably 230 g or more and 555 g or less. If the roll mass <with core> is less than 230 g, in order to obtain a desired winding length, the basis weight becomes low and the water absorption property deteriorates. On the other hand, if the roll mass <with core> is more than 555 g, in order to obtain a desired winding length, the basis weight becomes high and ply peeling is likely to occur. The lower limit value of the above range of the roll mass <with core> of the paper towel roll 1 is more preferably 265 g or more, and still more preferably 295 g or more. Further, the upper limit value of the above range of the roll mass <with core> of the paper towel roll 1 is more preferably 495 g or less, and still more preferably 460 g or less. When the roll width W of the paper towel roll 1 is not 280 mm, it is converted to the mass per 280 mm by proportional calculation.

[0035] (Roll density) The roll density of the paper towel roll 1 is preferably 0.04 g / cm 3 or more and 0.13 g / cm 3 or less. If the roll density of the paper towel roll 1 is less than 0.04 g / cm 3 , the basis weight becomes low and the water absorption property deteriorates. On the other hand, if the roll density of the paper towel roll 1 is more than 0.13 g / cm 3 , the basis weight becomes high and ply peeling is likely to occur. The lower limit value of the above range of the roll density of the paper towel roll 1 is more preferably 0.05 g / cm 3 or more, and still more preferably 0.06 g / cm 3 or more. Further, the upper limit value of the above range of the roll density of the paper towel roll 1 is more preferably 0.11 g / cm 3 or less, and still more preferably 0.09 g / cm 3 or less.

[0036] Roll density is expressed as (roll mass <without core>) ÷ (roll volume). As mentioned above, roll mass <without core> is the mass of one paper towel roll per roll width W280mm, excluding the core 1d. Roll volume is the volume of one paper towel roll per roll width W280mm. If the roll width W is not 280mm, it is converted to the volume per 280mm using proportional calculation. Roll volume is expressed as roll cross-sectional area × roll width W (converted to per 280mm).

[0037] For example, if the roll mass (without core) is 344g, the winding diameter DR is 150mm, and the core outer diameter DI is 44mm, then the roll density = 344g ÷ [{3.14 × (150mm ÷ 2 ÷ 10) 2 -3.14 × (44mm ÷ 2 ÷ 10) 2} × (280 mm ÷ 10) = 0.076 g / cm³ 3 This is the result.

[0038] (winding density) The winding density of paper towel roll 1 is 0.20 m / cm. 2 More than 0.56m / cm 2 Preferably, the winding density of the paper towel roll 1 is 0.20 m / cm². 2 Making it smaller would increase the basis weight, making the ply more prone to peeling. On the other hand, if the winding density of paper towel roll 1 is 0.56 m / cm 2 If the density is increased beyond this, the basis weight decreases, resulting in poorer water absorption. The lower limit of the winding density within the above range for paper towel roll 1 is 0.24 m / cm². 2 It is more preferable that it be greater than or equal to 0.30 m / cm 2 It is even more preferable that the above conditions are met. Furthermore, the upper limit of the above range for the winding density of the paper towel roll 1 is 0.50 m / cm 2 It is more preferable that the following is the case: 0.45 m / cm 2 The following is even more preferable:

[0039] Winding density is expressed as (winding length × number of plies) ÷ (roll cross-sectional area). For example, in the case of a winding length of 28.5m, 2 plies, winding diameter DR 150mm, and core outer diameter DI 44mm, winding density = (28.5m × 2) ÷ {3.14 × (150mm ÷ 2 ÷ 10)} 2 -3.14 × (44mm ÷ 2 ÷ 10) 2} = 0.35 m / cm 2 This is the result.

[0040] <Paper towel sheets> It is preferable that the paper towel sheet 1x is embossed on at least one ply (the ply of the surface 1a), and then the sheet is bonded with glue (e.g., plybond glue) to laminate it onto the product plies (2-3 plies), with 2 plies being more preferable. If the product plies are 3 plies, it is preferable that the surface 1a consists of 2 plies and the back surface 1b consists of 1 ply. This configuration makes it less likely for glue residue to be generated. Alternatively, a mixture of glue and water may be used instead of plybond glue.

[0041] (Wet pulp weight content) Furthermore, the paper towel sheet 1x contains wet pulp, and it is preferable that the weight content of wet pulp in the product ply is 60% by mass or more and 100% by mass or less. If the weight content of wet pulp is less than 60% by mass, the water absorption will be poor when the basis weight is low. The lower limit of the weight content of wet pulp is more preferably 70% by mass or more, and even more preferably 80% by mass or more. Here, wet pulp refers to pulp with a solid content of 70% by mass or less, and also includes slush pulp (also called flow-fed pulp) with a solid content of about 3% by mass, and the proportion of this flow-fed pulp should be 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more. The solid content of dry pulp (sheet) is about 90%.

[0042] (Basic weight) The basis weight per ply of a 1x paper towel sheet (hereinafter simply referred to as "basis weight of a 1x paper towel sheet") is 30 g / m². 2 More than 56g / m2 The basis weight of a 1x paper towel sheet is 30 g / m². 2 Making it smaller results in poorer water absorption. On the other hand, the basis weight of a 1x paper towel sheet is 56 g / m². 2 Making it larger than this will make the ply more prone to peeling. The lower limit of the above range for the basis weight of a 1x paper towel sheet is 34 g / m². 2 Preferably, it is 38 g / m 2 It is more preferable that the above is true. Also, the upper limit of the above range for the basis weight of a 1x paper towel sheet is 50 g / m². 2 Preferably, it is 46 g / m 2 The following is more preferable: The basis weight of a paper towel sheet 1x can be measured according to JIS P 8124. Note that "product ply" means 2 plies if the paper towel sheet 1x is 2 plies, and 3 plies if the paper towel sheet 1x is 3 plies.

[0043] (Paper thickness per 10 plies) The paper thickness per 10 plies of a 1x paper towel sheet is preferably between 2.0 mm / 10 plies and 4.0 mm / 10 plies. If the paper thickness per 10 plies of a 1x paper towel sheet is less than 2.0 mm / 10 plies, the water absorption will be poor. On the other hand, if the paper thickness per 10 plies of a 1x paper towel sheet is greater than 4.0 mm / 10 plies, the plies will peel off easily. The lower limit of the above range for the paper thickness per 10 plies of a 1x paper towel sheet is more preferably 2.3 mm / 10 plies or more, and even more preferably 2.6 mm / 10 plies or more. The upper limit of the above range for the paper thickness per 10 plies of a 1x paper towel sheet is more preferably 3.6 mm / 10 plies or less, and even more preferably 3.3 mm / 10 plies or less.

[0044] The paper thickness per 10 plies of a 1x paper towel sheet can be measured using a thickness gauge (the "PEACOCK" dial thickness gauge manufactured by Ozaki Seisakusho Co., Ltd.). The measurement conditions are a measurement load of 37.85 gf / cm².2 The measuring probe has a diameter of 30 mm. The sample is placed between the probe and the measuring platform, and the gauge is read when the probe is lowered at a speed of 1 mm or less per second. As the sample, 10 plies of a 1x paper towel sheet (5 sets of 2 plies) are used for measurement. The measurement is repeated 10 times at different locations, and the average of the measurement results is used as the final paper thickness. In the case of 3 plies, 9 plies (3 sets of 3 plies) are measured, and the equivalent of 10 plies is calculated proportionally.

[0045] (Product ply paper thickness) The paper thickness per product ply of a paper towel sheet 1x is preferably between 0.40 mm / product ply and 0.80 mm / product ply. If the paper thickness per product ply of a paper towel sheet 1x is less than 0.40 mm / product ply, the water absorption will be poor. On the other hand, if the paper thickness per product ply of a paper towel sheet 1x is greater than 0.80 mm / product ply, the ply will peel off easily. The lower limit of the above range for the paper thickness per product ply of a paper towel sheet 1x is more preferably 0.45 mm / product ply or more, and even more preferably 0.50 mm / product ply or more. The upper limit of the above range for the paper thickness per product ply of a paper towel sheet 1x is more preferably 0.72 mm / product ply or less, and even more preferably 0.68 mm / product ply or less.

[0046] The paper thickness per product ply of a 1x paper towel sheet is determined by measuring the paper thickness per 10 plies as described above, and then converting the measured value to the paper thickness per product ply.

[0047] (specific volume) The specific volume (product ply) of one paper towel sheet is 11 cm³. 3 / g or more 17cm 3 It is preferable that the value be less than or equal to / g. The specific volume of 1x paper towel sheet is 11cm³ 3 If the amount is less than / g, the water absorption will be reduced. On the other hand, the specific volume of 1x paper towel sheet is 17cm³. 3Increasing the value above / g makes the ply more prone to peeling. It also increases the likelihood of strike-through, resulting in more glue residue adhering to the product. The lower limit of the specific volume within the above range for a 1x paper towel sheet is 12cm³. 3 It is more preferable that it be 13cm or more per g. 3 It is even more preferable that it be 1 / g or more. Also, the upper limit of the above range for the specific volume of a paper towel sheet 1x is 16cm³. 3 It is more preferable that it be less than / g, and 15cm 3 It is even more preferable that it be less than or equal to / g. The specific volume of a paper towel sheet 1x is calculated by dividing the paper thickness per ply of the paper towel sheet 1x by the basis weight per ply, and the volume per unit (g) (cm³). 3 It is represented as ).

[0048] (DMDT) The Dry Machine Direction Tensile Strength (DMDT) of a paper towel sheet 1x (product ply) in the MD direction during dry conditions, according to JIS P 8113, is preferably 7N / 25mm or more and 14N / 25mm or less. More preferably, the lower limit of the above range for the tensile strength DMDT of the paper towel sheet 1x is 8N / 25mm or more, and even more preferably 9N / 25mm or more. More preferably, the upper limit of the above range for the tensile strength DMDT of the paper towel sheet 1x is 13N / 25mm or less, and even more preferably 12N / 25mm or less.

[0049] (DCDT) The Dry Cross Direction Tensile Strength (DCDT) of a paper towel sheet 1x (product ply) in the CD direction when dry, according to JIS P 8113, is preferably 7N / 25mm or more and 14N / 25mm or less. More preferably, the lower limit of the DCDT of the paper towel sheet 1x is 8N / 25mm or more, and even more preferably 9N / 25mm or more. More preferably, the upper limit of the DCDT of the paper towel sheet 1x is 13N / 25mm or less, and even more preferably 12N / 25mm or less.

[0050] The tensile strengths DMDT and DCDT of a 1x paper towel sheet are measured in accordance with JIS P 8113.

[0051] (DGMT) The Dry Geometric Tensile Strength (DGMT), which is the square root of the product of the tensile strength DMDT and tensile strength DCDT of a 1x (2-ply) paper towel sheet, is preferably 7N / 25mm or more and 14N / 25mm or less. More preferably, the lower limit of the above range for the DGMT of a 1x paper towel sheet is 8N / 25mm or more, and even more preferably 9N / 25mm or more. More preferably, the upper limit of the above range for the DGMT of a 1x paper towel sheet is 13N / 25mm or less, and even more preferably 12N / 25mm or less.

[0052] The DGMT of a 1x paper towel sheet is calculated from the tensile strengths DMDT and DCDT measured in accordance with JIS P 8113.

[0053] If the tensile strengths DMDT, DCDT, and DGMT of a 1x paper towel sheet are reduced to below the lower limit of the above range, the basis weight will decrease, resulting in poor water absorption. On the other hand, if the tensile strengths DMDT, DCDT, and DGMT of a 1x paper towel sheet are increased to above the upper limit of the above range, the basis weight will increase, making the ply more prone to peeling.

[0054] (Sheet length) The length of the paper towel sheet 1x in the roll winding direction (circumferential direction) between perforations 1c and adjacent perforations 1c (hereinafter referred to as "sheet length") is preferably 100 mm or more and 250 mm or less. If the sheet length of the paper towel sheet 1x is less than 100 mm, the amount of water absorbed per sheet will decrease. On the other hand, if the sheet length of the paper towel sheet 1x is greater than 250 mm, the amount of water absorbed per sheet will become unnecessarily large. The lower limit of the above range for the sheet length of the paper towel sheet 1x is more preferably 130 mm or more, and even more preferably 150 mm or more. The upper limit of the above range for the sheet length of the paper towel sheet 1x is more preferably 230 mm or less, and even more preferably 210 mm or less.

[0055] (Water absorption) The water absorption capacity per unit area of ​​a 1x (product ply) paper towel sheet is 300 g / m². 2 More than 600g / m 2 The following applies: Water absorption per unit area is 300 g / m². 2 Making it smaller results in poor water absorption. On the other hand, the water absorption per unit area is 600 g / m². 2 Making it larger than that would increase the basis weight, making the ply more prone to peeling. The lower limit of the above range for water absorption per unit area of ​​a 1x paper towel sheet is 350 g / m². 2 Preferably, it should be 380 g / m² or more. 2 It is more preferable that the values ​​are as above. Furthermore, the upper limit of the above range for the amount of water absorbed per unit area of ​​a paper towel sheet 1x is 550 g / m². 2 Preferably, it is 500g / m² 2 The following is more preferable:

[0056] The water absorption per unit weight of a paper towel sheet 1x (product ply) is preferably 7 g / g or more and 15 g / g or less. If the water absorption per unit weight is less than 7 g / g, the water absorption will be poor. On the other hand, if the water absorption per unit weight is greater than 15 g / g, strike-throughs are more likely to occur, and more glue residue will adhere to the product. The lower limit of the above range for the water absorption per unit weight of a paper towel sheet 1x is more preferably 8 g / g or more, and even more preferably 10 g / g or more. The upper limit of the above range for the water absorption per unit weight of a paper towel sheet 1x is more preferably 14 g / g or less, and even more preferably 13 g / g or less.

[0057] (Method for measuring water absorption) Next, we will explain how to measure the water absorption capacity of each paper towel sheet 1x. Figure 2 is an explanatory diagram of the method for measuring the water absorption capacity of paper towel sheets.

[0058] To measure the water absorption capacity of a paper towel sheet 1x, first, a paper towel sheet 1x stacked on a product ply is taken and cut using a 7.6cm square template to create a rectangular test piece 20 (see Figure 2) with sides of 7.6cm. Next, the weight of the test piece 20 before water absorption is measured using an electronic balance. Then, the test piece 20 is set in a holder 21 (see Figure 2). The holder 21 is a jig that fixes the test piece 20 at three points and is made of metal that does not absorb moisture.

[0059] Next, fill a commercially available tray with distilled water to a depth of 2 cm, and immerse the test piece 20, which is set in the holder 21, in the distilled water for 2 minutes. After 2 minutes of immersion, remove the test piece 20 and the holder 21 from the distilled water, and as shown in Figure 2, hang the holder 21 and the test piece 20 from a rod placed in an empty water tank with the designated corner 20a facing upwards, close the lid of the water tank, and leave it for 5 minutes.

[0060] Next, the holder 21 and test piece 20 are removed from the water bath, the holder 21 is detached from the test piece 20, and the weight of the test piece 20 is measured using an electronic balance. Then, the amount of distilled water absorbed per unit area of ​​the test piece 20 (water g / sheet m) is determined from the change in weight of the test piece 20 before and after immersion in distilled water. 2 , 1m 2 Correct. Abbreviated as g / m 2 Calculate the amount of water absorbed per unit area (water g / sheet m). 2 By dividing this by the basis weight of the product ply of test piece 20, the water absorption per unit area (water g / sheet m) can be calculated. 2 ) / Basis weight (sheet g / sheet m 2 ) = Calculate the amount of water absorbed per unit weight (water g / sheet g, per gram; abbreviated as g / g). Measurements are taken 5 times for each sample, and the average value is used.

[0061] (Ply peel strength) The ply peel strength (the strength required to separate sheets) of the paper towel sheet 1x is preferably 8 cN / 76 mm or more and 50 cN / 76 mm or less. If the ply peel strength is less than 8 cN / 76 mm, the ply will peel off easily. On the other hand, if the ply peel strength is greater than 50 cN / 76 mm, the number of embossed patterns will increase or the amount of glue will increase, resulting in stronger ply adhesion, making strike-through more likely and increasing the amount of glue residue adhering to the product. Alternatively, the basis weight will decrease, resulting in poor water absorption. The lower limit of the above range for the ply peel strength of the paper towel sheet 1x is more preferably 10 cN / 76 mm or more, and even more preferably 12 cN / 76 mm or more. The upper limit of the above range for the ply peel strength of the paper towel sheet 1x is more preferably 38 cN / 76 mm or less, and even more preferably 30 cN / 76 mm or less.

[0062] The ply peel strength measurement method is in accordance with the tensile test method of JIS P 8113, using a tensile testing machine (STB-1225S, manufactured by A&D Co., Ltd.), and is performed under the standard conditions specified in JIS P 8111. First, a test piece measuring 76 mm in width and 130 mm in flow direction is taken from a sample of paper towel roll 1. Next, a 50 mm ply is peeled in the flow direction. One side of the peeled ply is fixed to the upper grip (width 80 mm) by clamping it 15 mm in the flow direction. The other side of the ply is also fixed to the lower grip (width 76 mm) by clamping it 15 mm in the flow direction. The distance between the grips is 70 mm. Next, the ply is pulled (peeled) at a tensile speed of 100 mm / min, and strength data is collected at least one point per 1 mm (at least 50 points for 50 mm). The data is averaged from a distance of 5 mm to 55 mm (measurement length 50 mm) after the start of measurement, and this is taken as the peel strength (N / 25 mm). However, if the distance from 5 mm to 55 mm after the start of measurement includes perforation 1c, the distance after the start of measurement can be changed to a range that does not include perforation 1c, such as from 20 mm to 70 mm (measurement length 50 mm).

[0063] (Embossed) Figure 3 shows an example of an embossed pattern. Figure 4 shows an example of radial embossing and closed-ring structure embossing. Note that the dashed line in Figure 4 represents the entire embossed pattern.

[0064] As shown in Figures 3 and 4, the paper towel sheet 1x is embossed and has an embossed pattern 10 in which two or more patterns are arranged at regular intervals. The presence of the embossed pattern 10 dramatically improves the aesthetic appeal of the paper towel sheet 1x and the paper towel roll 1. The embossed pattern 10 is applied to at least one ply (the ply on the surface 1a side of the paper towel sheet 1x). By providing the embossed pattern 10 on the paper towel sheet 1x, the amount of glue applied becomes appropriate, making it difficult to peel off and improving its aesthetic appeal. On the other hand, if the embossed pattern 10 is not provided on the paper towel sheet 1x, the aesthetic appeal decreases and it becomes difficult to adhere the plies. Note that the paper towel sheet 1x in this embodiment has a different uneven pattern 13 derived from the papermaking process than the embossed pattern 10.

[0065] As shown in Figures 3 and 4, it is preferable that the embossed pattern 10 includes radial embossing 11 and closed-ring structure embossing 12, and that each of the radial embossing 11 and the closed-ring structure embossing 12 is arranged alternately at equal intervals. Including radial embossing 11 dramatically improves the water diffusion properties of the paper towel sheet 1x, and including closed-ring structure embossing 12 dramatically improves the water retention properties of the paper towel sheet 1x. Furthermore, arranging the radial embossing 11 and the closed-ring structure embossing 12 alternately at equal intervals improves aesthetic appeal, allows for appropriate glue application, and results in appropriate peel strength. On the other hand, in the case of an embossed pattern that does not include at least one of the radial embossing 11 and the closed-ring structure embossing 12, aesthetic appeal decreases, the amount of glue applied becomes inappropriate, and peeling becomes more likely. It is preferable that the embossed pattern 10 is not parallel to either the MD direction or the CD direction.

[0066] (Radial embossing) The radial emboss 11 is not particularly limited in its overall shape, but it is preferable to have multiple linear embossings extending outward from the center (in a direction away from the center) or embossings of shapes made up of linear lines. By including the radial emboss 11 in the emboss pattern 10, water diffuses along the emboss, resulting in good water diffusion in the paper towel sheet 1x.

[0067] (Closed ring structure embossing) The closed-ring structure embossing 12, like the radial embossing 11, is not particularly limited in its overall shape, but it is preferable that it includes a linear or geometric embossing in the center surrounded by a geometric embossing on the outside to form a closed-ring structure. By including the closed-ring structure embossing 12 in the embossing pattern 10, water is retained inside the embossing, resulting in good water retention in the paper towel sheet 1x.

[0068] The shape of the lines forming the embossed pattern 10 can be a solid line, a dashed line, a dotted line, or a double dotted line, and the thickness can be any thickness. Among these, a solid line is preferable because it has good diffusion and water retention properties for absorbed water.

[0069] (Embossing depth) The embossing depth on the front side of the paper towel sheet 1x (product ply) (hereinafter also simply referred to as "embossing depth") is preferably 0.06 mm or more and 1.05 mm or less. If the embossing depth is less than 0.06 mm, the ply is more likely to peel off. On the other hand, if the embossing depth is greater than 1.05 mm, strike-through occurs more easily, and more glue residue adheres to the product. The lower limit of the above range for the embossing depth of the paper towel sheet 1x is more preferably 0.10 mm or more, and even more preferably 0.14 mm or more. The upper limit of the above range for the embossing depth of the paper towel sheet 1x is more preferably 0.55 mm or less, and even more preferably 0.35 mm or less.

[0070] Embossing depth is measured using a microscope. The KEYENCE VR-3100 One-Shot 3D Measurement Macroscope can be used. The KEYENCE VR-H1A software can be used for observing, measuring, and analyzing the microscope images. Measurement conditions are 25x magnification and a field of view of 12mm x 9mm. The magnification and field of view may be adjusted as needed depending on the desired embossing size.

[0071] Figure 5 shows the height profile on the XY plane as measured by a microscope, represented by shades of gray. Figure 6 shows the height profile on the XY plane as measured by a microscope, represented by a graph. Figure 7 shows how to determine the depth of the embossing pattern. Note that in Figure 5, the height of the surface 1a of the paper towel sheet 1x is represented by shades of gray, and the linear areas with different shades from the surrounding areas indicate individual embossing.

[0072] The depth of the embossing is determined by measuring the height difference of the embossing using the microscope described above. The measurement is performed on the surface 1a side of the paper towel sheet 1x. In addition, three turns of paper towel sheet 1x are removed from the paper towel roll 1, and the measurement is taken using the fourth turn of paper towel sheet 1x in its product ply sheet state. If there are perforations 1c, they are avoided during measurement.

[0073] First, draw line segment AB as shown in Figure 5 to obtain the height profile shown in Figure 6. Line segment AB should be drawn across the embossing. Line segment AB should be drawn in the width direction (CD direction) of the paper towel sheet 1x. However, if the spacing between embossings is narrow, for example, 2 mm or less, and the height of the raised parts described below becomes low, the line segment may be drawn diagonally or in the direction of the flow. The height profile is a (measured) cross-sectional curve S that represents the surface irregularities of the actual paper towel sheet 1x sample. However, it also contains noise (steep peaks caused by fiber clumps on the surface of the paper towel sheet 1x, fibers extending in a whisker-like manner, or areas without fibers), and it is necessary to remove such noise peaks when calculating the height difference of the irregularities.

[0074] Therefore, the (measured) cross-sectional curve S in Figure 6 is smoothed with a weighted average radio button filter size of ±12 to obtain the cross-sectional curve W in Figure 7. Note that smoothing using the weighted average radio button filter can be obtained automatically using the analysis software mentioned above. Then, in the graph shown in Figure 7, the average of the maximum values ​​on the vertical axis of the convex part H1 and the convex part H2 adjacent to convex part H1 is calculated, and the minimum value on the vertical axis at the concave part D1 sandwiched between convex parts H1 and H2 is found. The value obtained by subtracting the minimum value from the average of the maximum values ​​obtained in this way is taken as the provisional embossing depth. Then, as shown in Figure 7, the same measurement is performed at a total of two consecutive locations on the cross-sectional curve (a total of two consecutive locations: the concave part D1 and the concave part D2 sandwiched between convex parts H3 and H4) (at this point, two measurement results are obtained). Subsequently, the roll 1 is rotated 90 degrees three times in the flow direction of the paper towel sheet 1x, and the same measurements as above are taken at each position (a total of 4 measurement positions in the flow direction). The average value of these 8 positions (2 x 4) is then adopted as the embossing depth. While visually checking the embossed area in Figure 5, the height profile in Figure 6 is checked to determine the recessed and raised areas.

[0075] Furthermore, since the paper towel sheet 1x of the present invention has a ridged pattern 13 (see Figure 3) derived from the papermaking process, which is different from the embossed pattern, variations in the height of the convex parts on either side of the recess are observed. Therefore, if the difference in the vertical axis values ​​between the convex parts flanking the recess (for example, convex parts H3 and H4 flanking the recess D2) is 0.2 mm or more, measurements should be taken at locations that avoid that area.

[0076] (Root mean square height of surface roughness) The root mean square height Sq of the surface roughness of the back surface 1b of the paper towel sheet 1x (product ply) is preferably 38 μm or more and 125 μm or less. It is preferable that the back surface 1b of the paper towel sheet 1x does not have an embossed pattern 10. If the root mean square height Sq of the surface roughness of the back surface 1b is less than 38 μm, the water absorption will be poor. On the other hand, if the root mean square height Sq of the surface roughness of the back surface 1b is greater than 125 μm, strike-through will occur more easily, and more glue residue will adhere to the product. The lower limit of the above range for the root mean square height Sq of the surface roughness of the back surface 1b is more preferably 50 μm or more, and even more preferably 58 μm or more. The upper limit of the above range for the root mean square height Sq of the surface roughness of the back surface 1b is more preferably 95 μm or less, and even more preferably 83 μm or less.

[0077] The root mean square height (Sq) of the surface roughness of the back surface 1b is measured using a microscope. The KEYENCE VR-6100 one-shot 3D measuring microscope can be used. The VR6000 application can be used for observing, measuring, and analyzing the microscope images. The measurement conditions are 38x magnification and a field of view of 8mm x 6mm. The magnification and field of view may be changed as appropriate.

[0078] Figure 8 shows the height profile of the back surface of a paper towel sheet on the XY plane, as measured by a microscope, using shades of gray.

[0079] The image obtained, shown in Figure 8, is then filtered. Specifically, an S-filter (low-pass filter) is used to remove components on a scale smaller than the cutoff wavelength, and an L-filter (high-pass filter) is used to remove components on a scale larger than the cutoff wavelength. Here, the S-filter is set to 500 μm and the L-filter to 8 mm. Once the S-filter and L-filter are selected, the root mean square height (Sq) is automatically calculated.

[0080] The root mean square height Sq of the surface roughness of the reverse side 1b is measured on the reverse side 1b using the fourth turn of paper towel sheet 1x, after removing three turns of paper towel sheet 1x from the paper towel roll 1, in the state of the product ply (2-3 ply) sheet. If there are perforations 1c, these are avoided during measurement. Measurements are taken at two locations in the width direction (CD direction) of the paper towel roll 1, and then the paper towel roll 1 is rotated 90 degrees three times in the flow direction (MD direction) of the paper towel sheet 1x, and the same measurement is taken at each position (a total of 4 measurement locations in the flow direction). The average of these 8 locations (2 x 4) is finally adopted as the root mean square height Sq.

[0081] (Number of embossed areas) Of the embossing patterns 10, the number of short embossings with a longest part of 20 mm or less per unit area (hereinafter simply referred to as "number of short embossings") is greater than the number of long embossings with a longest part of more than 20 mm per unit area (hereinafter simply referred to as "number of long embossings"), and is 10 per 100 cm. 2 More than 500 pieces / 100cm 2 Preferably, the number of short embossed pieces should be 10 pieces / 100cm. 2 If the number of embossing patterns is reduced to less than 500 per 100cm, the embossing becomes less visible, the aesthetic appeal of embossing pattern 10 is diminished, and the ply becomes more prone to peeling. On the other hand, if the number of short embossing patterns is 500 per 100cm 2 If the number of embossed marks exceeds a certain limit, strike-throughs become more likely, and more glue residue adheres to the product. The lower limit of the above range for the number of short embossed marks is 30 marks / 100cm.2 It is more preferable to have more than 50 pieces / 100cm 2 It is even more preferable that this is the case. Also, the upper limit of the above range for the number of short embossing marks is 300 marks / 100cm. 2 It is more preferable that the following conditions be met: 150 pieces / 100cm 2 The following is even more preferable:

[0082] Of the embossing patterns 10, the number of long embossings with a maximum length exceeding 20mm is 0 per 100cm. 2 More than 50 pieces / 100cm 2 Preferably, the number of long embossed areas should be 50 per 100 cm. 2 If the number of embossed marks exceeds a certain limit, strike-throughs become more likely, and more glue residue adheres to the product. The upper limit of the above range for the number of embossed marks on long-length embossed surfaces is 30 marks / 100cm. 2 It is more preferable that the following conditions be met: 10 pieces / 100cm 2 The following is even more preferable:

[0083] (How to count embossing marks) This section explains how to count the embossing in embossing pattern 10. Embossings in embossing pattern 10 that are spaced apart from each other are considered as one. That is, embossings where lines touch are counted as one embossing. For example, the radial embossing 11 shown in Figure 4 includes one embossing 11a which contains a central rectangular embossing and diamond-shaped embossings that radiate outwards from it, and four V-shaped embossings 11b to 11e which are placed between the diamond-shaped embossings of embossing 11a. In other words, the number of embossings in radial embossing 11 is five. Also, the closed ring structure embossing 12 shown in Figure 4 includes one outermost ring-shaped embossing 12a, an inner ring-shaped embossing and a linear embossing 12b touching it, an inner rectangular embossing 12c, and an innermost rectangular embossing 12d. In other words, the number of embossings in closed ring structure embossing 12 is four.

[0084] (How to count the number of embossed areas per unit area) This section explains how to count the number of embossed areas per unit area. To count the number of embossed areas per unit area, remove three turns of paper towel sheets 1x from the paper towel roll 1, and count the embossed areas of the fourth and fifth turns of paper towel sheets 1x by visual inspection or using a microscope. Count the number of embossed areas within a 10cm x 10cm area at two locations along the axis of each of the fourth and fifth turns of paper towel sheets 1x (the axis of the paper towel roll 1). If a frame defining the 10cm x 10cm area crosses an embossed area, the embossed areas crossed by the frame are not counted. Then, average the values ​​from the two locations (a total of four locations) along the width direction (the axis of the paper towel roll 1) of the fourth and fifth turns of paper towel sheets 1x.

[0085] (Longest part of the embossing) Figure 9 is an explanatory diagram of the longest part of the embossing. Note that in Figure 9, for clarity, the line indicating the longest part L is shown adjacent to the embossing E; however, in reality, it represents the length along the embossing E.

[0086] The longest part of an embossed surface, in the case of a linear embossing, refers to the longest portion that can be drawn in a single stroke. For embossings with a specific shape that is not linear, it refers to the longest straight-line distance within that shape. The length of the longest part of an embossed surface is measured using a measuring tape or microscope.

[0087] For example, in the linear embossing E shown in Figures 9(a) and (b), the longest part that can be drawn in a single stroke is the distance from one end to the other of each embossing E, which is the longest part L of the embossing. Similarly, in the annular embossing E shown in Figure 9(c), the longest part that can be drawn in a single stroke is the distance from a predetermined position P to one side in the circumferential direction and back to the predetermined position P, which is the longest part L of the embossing. Furthermore, in the embossing E shown in Figure 9(d), which has a shape where two lines intersect, the longest part that can be drawn in a single stroke is the portion shown in Figure 9(d), which is the longest part L of the embossing. Finally, in the embossing E shown in Figures 9(e) and (f), which has a predetermined shape that is not linear, the longest part L of the embossing is the longest straight-line distance within that shape. Furthermore, in the embossing 11a of the radial embossing 11 shown in Figure 4, the longest part that can be drawn in a single stroke is the entire embossing, as shown by the dashed line in Figure 4, and the longest part L of the embossing extends from a predetermined position P to one side and returns to the same predetermined position P. Also, in the embossing 12b of the closed ring structure embossing 12 shown in Figure 4, the longest part that can be drawn in a single stroke is the part of the circle excluding the two straight lines and a portion of the area between the two straight lines, as shown by the dashed line in Figure 4, and the longest part L of the embossing extends from a predetermined position P1 to a predetermined position P2.

[0088] <How to manufacture paper towel rolls> Figure 10 shows a part of the papermaking process for paper towel rolls.

[0089] Paper towel roll 1 can be manufactured, for example, in the following order: papermaking and creping, embossing and bonding, and roll winding.

[0090] In the papermaking process, raw pulp is mixed in a predetermined ratio and manufactured in a paper machine to obtain a 1-ply raw material sheet. In the papermaking process for the paper towel sheet 1x, drying is performed using through-air drying (TAD) papermaking technology. At this time, in the papermaking process, a different uneven pattern 13 (see Figure 3) originating from the papermaking process (fabric), distinct from the embossing pattern 10 described above, is applied to the paper towel sheet 1x. Having this uneven pattern 13 further increases the water absorption capacity of the paper towel sheet 1x.

[0091] As shown in Figure 10, for example, a paper machine 30 used in the papermaking process includes two fabrics 31, 32, a forming roll 33, at least one (two in Figure 10) through-air dryer 34, a Yankee dryer 35, and a headbox 36.

[0092] The first fabric 31 is, for example, a TAD fabric having an uneven surface, and is provided to loop around the forming roll 33 and a plurality of guide rolls 37a, and rotates in a predetermined direction. The forming roll 33 is positioned upstream in the flow direction of the paper web (wet paper) 38b. The second fabric 32 is, for example, a forming wire (papermaking mesh), and is provided to loop around a plurality of guide rolls 37b, and rotates in a predetermined direction. The second fabric 32 is positioned opposite the first fabric 31 along the forming roll 33.

[0093] The headbox 36 injects (supplies) pulp slurry 38a between the first fabric 31, which is aligned with the forming roll 33, and the second fabric 32, which is opposite to it. The pulp slurry 38a from the headbox 36 is sandwiched between the first fabric 31 and the second fabric 32 by the forming roll 33, forming a paper web (wet paper) 38b.

[0094] The first fabric 31 passes through the through-air dryer 34 downstream of the forming roll 33. The paper web 38b, having passed through the forming roll 33, separates from the second fabric 32 before the through-air dryer 34 and passes through the through-air dryer 34 together with the first fabric 31. The through-air dryer 34 removes water from the paper web 38b and dries it. There may be one or two through-air dryers 34.

[0095] The Yankee dryer 35 is positioned downstream of the through-air dryer 34. The paper web 38b that has passed through the through-air dryer 34 is separated from the first fabric 31 and conveyed along the drum of the Yankee dryer 35. The Yankee dryer 35 gives the paper web 38b final drying. In Figure 10, a Yankee hood is shown on the Yankee dryer 35, but the hood is not required. Crepes may be applied in the Yankee dryer 35. When drying the paper web 38b, it is preferable that the rate of change in moisture content of the paper web 38b before and after the through-air dryer 34 is greater than the rate of change in moisture content before and after the Yankee dryer 35.

[0096] "Originating from the papermaking process" means that in the papermaking process of paper towel sheets 1x, a pattern of irregularities is applied between the headbox 36 of the papermaking machine 30 and the outlet of the Yankee dryer 35. In particular, the irregularities are formed when the paper web 38b is dried together with the first fabric 31 in the through air dryer 34. Specifically, the irregularity pattern 13 is applied by the first fabric 31, which has irregularities, in a part of the papermaking process shown in Figure 10. The irregularity pattern 13 can be changed as appropriate by changing the pattern (fine pattern, coarse pattern) of the first fabric 31. Changing the irregularity pattern 13 changes the specific volume (paper thickness), but it is preferable to select a pattern such that the specific volume in the roll state falls within the numerical range described above.

[0097] In the embossing and bonding process, after embossing the sheet, each sheet is laminated to form product plies (for example, 2 to 3 plies (preferably 2 plies)). When laminating the product plies, a glue containing polyvinyl alcohol (PVOH) is applied for bonding. Using a glue containing PVOH makes it less likely for glue residue to accumulate.

[0098] As described above, the paper towel roll 1 according to this embodiment is a paper towel roll 1 in which sheets with an embossed pattern 10 applied to at least one ply are bonded together with glue, and the laminated paper towel sheets 1x, which are then wound into a roll, are formed. The number of short embossed patterns with a longest portion of 20 mm or less is greater than the number of long embossed patterns with a longest portion exceeding 20 mm, and the number of short embossed patterns is 10 per 100 cm. 2 More than 500 pieces / 100cm 2 The basis weight of one sheet of this product is 30 g / m². 2 More than 56g / m 2 The following is the water absorption capacity per unit area of ​​one sheet of product ply paper towels: 300 g / m² 2 More than 600g / m 2 The following applies:

[0099] Therefore, according to this embodiment, even when an embossed pattern 10 is applied to a paper towel sheet 1x obtained by TAD papermaking technology and wound up in 2 to 3 plies using glue, it is possible to provide a paper towel roll 1 in which the aesthetic appearance of the embossed pattern 10 is good, the amount of glue residue is small, and the plies are less likely to peel off.

[0100] Although the present invention has been described above based on the above embodiments, the present invention is not limited to the contents of the above embodiments, and can naturally be modified as appropriate without departing from the present invention. In other words, all other embodiments, examples, and operational techniques made by those skilled in the art based on these embodiments are of course included in the scope of the present invention. [Examples]

[0101] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited in any way by the following examples.

[0102] (Examples 1-18 and Comparative Examples 1-7) Paper towel rolls (kitchen towels) for Examples 1-18 and Comparative Examples 1-7, as shown in Tables 1 and 2, were manufactured through the processes of TAD papermaking and creping, embossing and bonding, and roll winding. Each paper towel roll was then measured or evaluated for the following four items: "water absorption of the paper towel," "resistance to ply peeling," "aesthetic quality of the embossed pattern," and "minimal glue residue." Each parameter was measured according to the standards or measurement methods described above.

[0103] (The absorbency of paper towels) The evaluation of "paper towel absorbency" is based on the amount of water absorbed per unit area of ​​the paper towel sheet (product ply), and the evaluation criteria are as follows: ◎: Water absorption capacity is 380g / m 2 That's all. ○: Water absorption capacity is 350g / m 2 More than 380g / m 2 less than △: Water absorption capacity is 300g / m 2 More than 350g / m 2 less than ×: Water absorption capacity is 300g / m 2 less than

[0104] (Resistance to ply peeling) The evaluation of "resistance to ply peeling" was based on a sensory evaluation by 30 monitors. When monitors used paper towels wet with water, they were asked to choose either "ply peels easily, making it difficult to use" or "ply peels difficult, making it easy to use." The evaluation criteria were as follows: ◎: "The ply doesn't peel off easily and is easy to use" - 28 or more people ○: "The ply is difficult to peel off and easy to use" was selected by 26 to 27 people. △: "The ply is difficult to peel off and easy to use" was selected by 24 to 25 people. ×: "The ply is difficult to peel off and easy to use" was selected by 23 or fewer people.

[0105] (The aesthetic appeal of embossed patterns) The evaluation of "Aesthetic Appeal of Embossed Patterns" was a sensory evaluation conducted by 30 monitors regarding the aesthetic appeal of the embossed patterns. For the evaluation of "Aesthetic Appeal of Embossed Patterns," the 30 monitors used each paper towel roll and selected either "Good" or "Bad" regarding the aesthetic appeal of the embossed patterns. The evaluation was then conducted according to the following criteria. ◎: More than 28 people rated it as "Good". ○: 26 to 27 people answered "Good" △: 24 to 25 people gave a "Good" rating. ×: 23 or fewer people answered "Good".

[0106] (Low amount of glue residue) The evaluation of "low amount of glue residue" was a sensory evaluation conducted by 30 monitors regarding the amount of glue residue attached to the paper towel rolls. Each of the 30 monitors used a different paper towel roll and selected either "low" or "high" the amount of glue residue. The evaluation was then conducted according to the following criteria. ◎: More than 28 people answered "few". ○: "Few" is between 26 and 27 people. △: "Few" is between 24 and 25 people. ×: "Few" is 23 people or less

[0107] The results obtained are shown in Tables 1 and 2.

[0108] [Table 1]

[0109] [Table 2]

[0110] As shown in Tables 1 and 2, in the paper towel rolls (paper towel sheets) of Examples 1 to 18, there were no "×" ratings in the evaluations of "water absorption of paper towels," "resistance to ply peeling," "aesthetic quality of embossed patterns," and "minimal glue residue." On the other hand, in the paper towel rolls (paper towel sheets) of Comparative Examples 1 to 7, at least one of the evaluations of "water absorption of paper towels," "resistance to ply peeling," "aesthetic quality of embossed patterns," and "minimal glue residue" received an "×" rating.

[0111] Thus, according to this disclosure, it has been confirmed that even when an embossed pattern is applied to a paper towel sheet obtained using TAD papermaking technology and wound into 2-3 plies using glue, it is possible to provide a paper towel roll with good aesthetic appeal of the embossed pattern, a small amount of glue residue, and resistance to ply peeling. [Explanation of Symbols]

[0112] 1: Paper towel roll 1x: Paper towel sheets 1b: Back side 10: Embossed pattern

Claims

1. A paper towel roll is formed by laminating two to three sheets of paper towel material, each sheet having an embossed pattern on at least one ply, with glue bonding, and then winding the resulting roll into a paper towel roll. Of the aforementioned embossed patterns, the number of short embossed patterns with a longest portion of 20 mm or less is greater than the number of long embossed patterns with a longest portion exceeding 20 mm. The basis weight of the paper towel sheet in the product ply is 30 g / m². ２ 56g / m or more ２ The following: The water absorption capacity per unit area of ​​the product ply paper towel sheet is 300 g / m². ２ More than 600g / m ２ The following is A paper towel roll characterized by the following features.

2. The paper thickness of the paper towel sheet in the product ply is 0.4 mm or more and 0.8 mm or less. The paper towel roll according to feature 1.

3. The ply peel strength of the aforementioned paper towel sheet is 8 cN / 76 mm or more and 50 cN / 76 mm or less. A paper towel roll according to claim 1 or 2.

4. The number of short embossed areas per unit area is 10 per 100 cm². ２ More than 500 pieces / 100cm ２ That is A paper towel roll according to claim 1 or 2.

5. The root mean square height of the surface roughness on the back surface of the paper towel sheet of the product ply is 38 μm or more and 125 μm or less. A paper towel roll according to claim 1 or 2.

6. The water absorption capacity per unit weight of the paper towel sheet in the product ply is 7 g / g or more and 15 g / g or less. A paper towel roll according to claim 1 or 2.

7. The aforementioned paper towel sheet contains wet pulp, and the weight content of the wet pulp is 60% or more and 100% or less. A paper towel roll according to claim 1 or 2.

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