Paper towel roll and the like

Abstract

To provide a paper towel roll or the like which is excellent in water absorbency, has high strength, is hardly torn even when getting wet with water, and further has a soft feeling even if the paper towel has a high basis weight.SOLUTION: In a paper towel roll or the like in which a paper towel laminated in two or more plies and three or less plies is wound around a core in a roll shape, the paper towel has a basis weight per product ply of 40g / m2 or more and 80g / m2 or less, a paper thickness per product ply of 0. 55mm or more and 1. 35mm or less, a specific volume per product ply of 9. 0cm3 / g or more and 24. 0cm3 / g or less, a tensile strength DMDT in the MD direction per product ply in a dry state based on the JISP8113 of / or more and / or less, and a tensile strength DCDT in the CD direction per product ply of wetter / wetter or more and wetter / wetter or less. 75mm 2100cN 6000cN 2100cN 75mm 75mm 75mm 6100cN, in the paper towel roll or the like, a water absorption amount per unit area is 350g / m2 or more and 810g / m2 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to through-air drying (TAD) paper towel rolls and the like. [Background technology]

[0002] In recent years, paper towel rolls and other products have become longer, but luxury products require not only longer lengths but also higher quality. Increasing the basis weight of paper towels improves water absorption, increases paper thickness, and increases strength. However, it is known that increasing strength also makes the paper stiffer and results in a poorer feel.

[0003] For example, Patent Document 1 discloses a rolled paper towel that has a core outer diameter within a certain range, is one-ply, has a high basis weight, and is highly absorbent, is easy to wind into a roll, is resistant to core crushing, is easy to use as a product, and has good logistics efficiency. However, high basis weight rolled paper towels have the problem of being strong, making the paper feel stiff, and having an inferior feel to the touch.

[0004] Therefore, when paper towels are made using the through air drying (Through Air Dryer, or simply "TAD") papermaking technology, which uses ventilation drying, the paper has an uneven surface, is thick, and has fewer inter-fiber bonds, resulting in lower strength and a better feel. Furthermore, water absorption is improved, and the strength-to-length ratio is reduced, resulting in a better feel. Furthermore, while horizontal strength is generally lower than vertical strength and is prone to tearing, reducing the strength-to-length ratio improves the balance between vertical and horizontal strength, making it less likely to tear even in the horizontal direction. However, on the other hand, TAD paper towels have the problem of being too absorbent, making them prone to tearing when absorbing water. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-20906 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above circumstances, and aims to provide a paper towel roll or the like that has good water absorption, high strength, is resistant to tearing even when wet, and has a soft texture, even if it is a paper towel with a high basis weight. [Means for solving the problem]

[0007] The inventors conducted extensive research and discovered that the above problems can be solved by specifying the basis weight, paper thickness, specific volume, tensile strength, and water absorption capacity of the paper towels in paper towel rolls, etc., in which two to three plies of paper towels are wound around a core in a roll shape, and have thus completed the present invention. (1) A first aspect of the present invention is a paper towel roll or the like in which two to three plies of paper towels are laminated and wound around a core in a roll shape, and the paper towels have a basis weight per product ply of 40 g / m 2 More than 80g / m 2 The thickness of each product ply is 0.55 mm or more and 1.35 mm or less, and the specific volume of each product ply is 9.0 cm 3 / g or more 24.0cm 3 / g or less, tensile strength in the MD direction per product ply in the dry state based on JIS P 8113 is 2100cN / 75mm or more and 6100cN / 75mm or less, tensile strength in the CD direction per product ply is 2100cN / 75mm or more and 6000cN / 75mm or less, and water absorption per unit area is 350g / m 2 More than 810g / m 2 The paper towel roll is characterized by the following:

[0008] (2) The second aspect of the present invention is the paper towel roll etc. described in (1), wherein the winding density is 0.15 m / cm 2More than 0.60m / cm 2 It is characterized by the following:

[0009] (3) A third aspect of the present invention is a paper towel roll or the like as described in (1) or (2), characterized in that the water absorption per unit mass of the paper towel is 8.0 g / g or more and 13.0 g / g or less.

[0010] (4) A fourth aspect of the present invention is the paper towel roll etc. described in (1) or (2), characterized in that the paper towel has a linear embossed pattern.

[0011] (5) A fifth aspect of the present invention is a paper towel roll or the like as described in (1) or (2), characterized in that the value of the tensile strength DMDT divided by the value of the basis weight per product ply is 41 or more and 95 or less.

[0012] (6) A sixth aspect of the present invention is a paper towel roll or the like as described in (1) or (2), characterized in that the value of the tensile strength DCDT divided by the value of the basis weight per product ply is 41 or more and 95 or less.

[0013] (7) A seventh aspect of the present invention is the paper towel roll etc. according to (1) or (2), characterized in that the roll softness is 1.2 mm or more and 4.2 mm or less.

[0014] (8) The eighth aspect of the present invention is the paper towel roll or the like according to (1) or (2), wherein the roll density is 0.05 g / cm 3 More than 0.15g / cm 3 It is characterized by the following:

[0015] (9) A ninth aspect of the present invention is the paper towel roll or the like according to (1) or (2), characterized in that the roll length is 18 m or more and 45 m or less.

[0016] (10) A tenth aspect of the present invention is the paper towel roll etc. described in (1) or (2), characterized in that the roll mass excluding the core is 170 g or more and 700 g or less.

[0017] (11) The eleventh aspect of the present invention is a paper towel roll or the like as described in (1) or (2), characterized in that the ratio of the tensile strength DMDT to the tensile strength DCDT is 0.95 or more and 1.30 or less. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a paper towel roll or the like that has good water absorption, high strength, is resistant to tearing even when wet, and has a soft texture, even when the paper towel has a high basis weight. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a perspective view of a paper towel roll according to an embodiment of the present invention. [Figure 2] 1 is a diagram showing an example of an embossed pattern on a paper towel roll or the like of the present invention. FIG. [Figure 3] 1A and 1B are diagrams showing examples of radial embossing and closed-ring structure embossing in an embossing pattern on a paper towel roll or the like of the present invention. [Figure 4] FIG. 1 is a diagram showing a method for measuring the arrangement angle of the embossed pattern in the kitchen towel roll of the present invention. [Figure 5] FIG. 1 is a diagram showing a height profile on the XY plane as observed by a microscope using shading. [Figure 6] FIG. 1 is a graph showing a height profile on the XY plane obtained by a microscope. [Figure 7] FIG. 10 is a diagram showing how to determine the embossing depth for an embossing pattern. [Figure 8] FIG. 1 is a diagram showing a method for measuring the water absorption of a paper towel sheet of the present invention. [Figure 9]1 is a diagram showing a portion of the papermaking process for the paper towel sheet of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out by appropriately modifying it within the scope of its gist.

[0021] In this specification, "paper towel rolls, etc." (hereinafter simply referred to as "rolls") refers to roll products in which paper towels, such as kitchen towels and cooking sheets, are wound into a roll. "paper towel sheets" (hereinafter simply referred to as "sheets") refers to sheet-like products in which paper towels are pulled out from a paper towel roll, etc., and cut along the perforations.

[0022] "MD direction" refers to the direction in which the paper towel runs through the machine, and "CD direction" refers to the direction perpendicular to the MD direction. In this specification, "MD direction of the roll" refers to the direction in which the paper towel is wound (Y direction in Figure 1), and "CD direction of the roll" refers to the direction perpendicular to the direction in which the paper towel is wound (X direction in Figure 1). "Axial direction" refers to the axial direction of the roll, which is the CD direction of the roll (X direction in Figure 1).

[0023] In this specification, the term "product ply" refers to a paper towel in which the number of plies is in a product state, without peeling off the stacked plies into one sheet.

[0024] <Paper towel rolls, etc.> Fig. 1 is a perspective view of a paper towel roll 1 according to one embodiment of the present invention. As shown in Fig. 1, the paper towel roll 1 according to this embodiment is a paper towel roll 1 formed by winding two-ply or three-ply stacked paper towels 1x into a roll. Preferably, the paper towels 1x have perforations 1c formed in the width direction of the roll at approximately equal intervals in the winding direction of the roll.

[0025] 1, the surface of the paper towel 1x facing the outside of the roll is referred to as surface 1a (surface of the paper towel 1x), and the surface facing the center of the roll is referred to as back surface 1b (back surface of the paper towel 1x). Also, the edge of the paper towel 1x is referred to as the outermost edge 1e of the paper towel roll 1.

[0026] Examples of uses for the paper towel rolls etc. 1 include rolls (kitchen paper rolls) of kitchen paper (sometimes called paper towels, cooking paper, etc.) used in home kitchens and restaurant kitchens to wipe away moisture or oil and remove dirt, as well as other rolls of sanitary paper.

[0027] <Paper towels> Paper towels 1x can be made by stacking base papers after a papermaking process, embossing them as needed, and then winding them into a roll to form paper towel rolls 1. Alternatively, the base papers may be embossed before being stacked and wound into a roll.

[0028] (Paper making method) The paper towel 1x is preferably produced by a through-air drying (hereinafter simply referred to as "TAD") papermaking method. The TAD papermaking method is a method in which air drying is performed in the dehydration and drying step of the papermaking process (it is preferable not to press-dehydrate the wet paper). By producing the paper towel 1x by the TAD papermaking method, the paper towel 1x can be provided with irregularities derived from the papermaking process, resulting in a bulky, soft paper towel 1x with excellent water absorbency.

[0029] (raw materials) The paper towel 1x may contain pulp fibers. The pulp fibers are preferably composed of 100% by mass of wood pulp containing at least one of NBKP (softwood bleached kraft pulp fiber) and LBKP (hardwood bleached kraft pulp fiber). The mass ratio of NBKP to LBKP (NBKP:LBKP) is preferably 40-100% by mass:60-0% by mass, more preferably 50-90% by mass:50-10% by mass, and even more preferably 60-80% by mass:40-20% by mass or more. If the amount of NBKP exceeds the above range and exceeds the amount of LBKP, the strength increases and the softness of the sheet decreases. If the amount of NBKP is less than the amount of LBKP, the paper towel 1x becomes more likely to tear when absorbing water. By setting the mass ratio of NBKP to LBKP within the above range, the cost of the paper towel 1x becomes appropriate and the paper towel 1x becomes less likely to tear even when absorbing water.

[0030] (Wet pulp blend) The wet pulp ratio (content ratio) in the paper towel 1x is preferably 50% by mass or more and 100% by mass or less. If the wet pulp ratio is 50% by mass or more, the water absorbency of the paper towel 1x will be good. On the other hand, if the wet pulp content is less than 50% by mass, the water absorbency will be poor if the basis weight is low. The lower limit of the wet pulp content is more preferably 70% by mass or more, and even more preferably 90% by mass or more.

[0031] (Uneven pattern resulting from the papermaking process) The surface of the paper towel 1x preferably has irregularities 11 resulting from the papermaking process, as shown in Figure 2. By having irregularities 11 resulting from the papermaking process, the water absorbency of the paper towel 1x is improved.

[0032] (Number of plies) The number of plies in the paper towel 1x is 2 or more and 3 or less. If the number of plies is less than 2, the absorbency of the roll 1 is poor, and if the number of plies is more than 3, the compactness is poor. In addition, the roll is tightly wound, and the softness of the sheet is poor. The number of plies is preferably 2.

[0033] (paper thickness) The paper thickness per product ply of the paper towel 1x (hereinafter simply referred to as "paper thickness") is 0.55 mm or more and 1.35 mm or less. If the paper thickness is less than 0.55 mm, the absorbency of the paper towel 1x will be poor. If the paper thickness is more than 1.35 mm, the softness of the paper towel 1x will be poor. The lower limit of the paper thickness is preferably 0.62 mm or more, and more preferably 0.75 mm or more. The upper limit is preferably 1.15 mm or less, and more preferably 1.00 mm or less.

[0034] The paper thickness is measured by the following method. (1) The device used is a thickness gauge (a dial thickness gauge "PEACOCK" manufactured by Ozaki Manufacturing Co., Ltd.). The measurement conditions are a measurement load of 3.7 kPa, a probe diameter of 30 mm, a sample placed between the probe and the measurement table, and the gauge is read when the probe is lowered at a speed of 1 mm per second or less. (2) The paper thickness is measured at 10 points, including 5 different points in the MD direction of the paper towel 1x and 5 points shifted from these 5 points in the CD direction. The results of these 10 measurements are averaged to determine the paper thickness. Note that it is important to measure the paper thickness at 10 different points, but the exact location is not important. (3) The sample is measured by stacking 10 plies (5 sets of 10 sheets of 2 plies), calculating the paper thickness per ply, and converting it to the number of product plies. If the sample is 10 sheets of 3 plies, measurements are taken by stacking 9 plies (3 sets of 3 ply sheets), and the paper thickness per ply is calculated from the measurement results and converted to the number of product plies.

[0035] (Basic weight) The basis weight of the product ply of paper towel 1x (hereinafter simply referred to as "basis weight") is 40 g / m 2 More than 80g / m 2 The basis weight is 40 g / m or less. 2 If the basis weight is less than 80 g / m, the water absorption capacity of one paper towel will be poor. 2 If the paper towel exceeds this limit, the softness of the paper towel will be reduced. The lower limit of the basis weight is 45 g / m 2 More than 50g / m 2More preferably, the upper limit is 75 g / m 2 Less than 70 g / m 2 The following is more preferable: The basis weight is measured in accordance with JIS P 8124.

[0036] (specific volume) The specific volume of the product ply for one paper towel is 9.0 cm 3 / g or more 24.0cm 3 / g or less. Specific volume is 9.0 cm 3 If the specific volume is less than 24.0 cm3 / g, the absorbency of one paper towel is poor. 3 If the specific volume exceeds 10.5 cm / g, the paper towel 1x becomes easily crushed and easily torn when absorbing water. 3 / g or more is preferable, and 13.0cm 3 / g or more is more preferable. The upper limit is 18.5 cm 3 / g or less is preferable, and 17.8cm 3 The specific volume of 1x paper towel is calculated by dividing the paper thickness of a predetermined number of plies (for example, product plies) of 1x paper towel by the basis weight of the predetermined number of plies, and then calculating the volume cm per unit g. 3 It is expressed as:

[0037] (Embossed) It is preferable that the paper towel 1x be laminated into two or three plies, with two plies being more preferable, after embossing at least the ply on the surface 1a. When laminating into two or three plies, it is preferable to use, for example, ply bond glue and apply the glue for adhesion. By bonding in this way to form two plies, the water absorption is increased and the adhesion between the plies is strong, so that the paper towel 1x is less likely to tear or peel off even when wet. Furthermore, water may be used instead of ply bond glue, or glue and water may be mixed.

[0038] (embossed pattern) The embossing of the paper towel 1x more preferably has an embossed pattern 12 in which two or more types of patterns are arranged at regular intervals. The presence of the embossed pattern 12 makes the stacked plies less likely to peel off. It is even more preferable that the embossed pattern 12 is provided on the ply on the surface 1a side of the paper towel 1x.

[0039] 3 is a diagram showing an example of the embossed pattern 12 of the paper towel 1x of this embodiment. The embossed pattern 12 preferably includes radial embossments 13 and closed-ring structure embossments 14, and the radial embossments 13 and the closed-ring structure embossments 14 are alternately arranged at equal intervals. The inclusion of the radial embossments 13 and the closed-ring structure embossments 14 improves the water absorbency of the paper towel 1x.

[0040] The lines forming the embossed pattern 12 may be solid, broken, one-dot chain, or two-dot chain, and may be of any thickness. Among these, solid lines are preferred because they have good water absorption properties.

[0041] (radial embossing) The overall shape of the radial embossing 13 is not particularly limited, but it is preferable that the embossing pattern 12 has a plurality of linear embossings extending from the center to the outside or a plurality of embossings in a shape made up of straight lines. When the embossing pattern 12 includes the radial embossing 13, the water absorbency is improved.

[0042] (closed ring structure embossed) The closed-ring structure embossment 14 is not particularly limited in overall shape, as with the radial embossment 13, but preferably has a linear or geometric embossment provided in the center that surrounds the closed-ring structure on the outside. The inclusion of the closed-ring structure embossment 14 in the embossed pattern 12 improves water absorption.

[0043] (embossing size) The lower limit of the size (area) of the embossed pattern 12 including one radial embossment 13 and one closed-ring structure embossment 14 is 16 cm 2 More than 28cm is preferable.2 More than 45cm is preferable. 2 More preferably, the upper limit is 250 cm 2 Less than 180cm is preferable 2 Less than 110cm is preferable. 2 More preferably, the size of the embossed pattern 12 is 16 cm 2 Less than 250cm 2 If it exceeds this value, the paper thickness is likely to fluctuate and the water absorbency is poor.

[0044] The size of the embossed pattern 12 is determined by calculating the area of ​​a rectangle E that includes (circumscribes) all of the embossed pattern 12, as shown in Figure 3. The sizes of the long and short sides of this rectangle E can be changed as appropriate depending on the size of the embossed pattern 12 (radial embossments 13 and closed-ring structure embossments 14).

[0045] (embossed area ratio) The lower limit of the embossed area ratio of the paper towel 1x (hereinafter simply referred to as "embossed area ratio") is preferably 4% or more, more preferably 6% or more, and even more preferably 8% or more. The upper limit of the embossed area is preferably 30% or less, more preferably 25% or less, and even more preferably 15% or less. If the embossed area ratio is less than 4%, the paper thickness is prone to fluctuate and water absorbency is poor. If the embossed area ratio exceeds 30%, the paper towel 1x becomes hard and the sheet softness is poor.

[0046] The embossed area ratio is determined by measuring the surface 1a side (outer surface of roll 1) of paper towel 1x, which corresponds to the top 10% of the roll 1, with a ruler or tape measure, measuring the area, and converting it into a ratio per unit area (area ratio). When the embossing is difficult to see with the naked eye or when the embossing width is narrow, it is preferable to measure the area using a one-shot 3D shape measuring machine (VR-6000, manufactured by Keyence Corporation). The top 10% of the roll 1 refers to the outermost 10% of the roll 1; for example, if the roll 1 is 30 m long, it refers to the first 3 m of use.

[0047] The above area ratio is calculated by the following procedure. (1) Inside a rectangle E that includes one embossing pattern 12 as shown in Figure 3, for embossments that are 0.1 mm or more and 4 mm or less in thickness and 5 mm or more in length, measure the total length by adding up the embossment lengths, and calculate the area of ​​the embossment by multiplying the total length (mm) by the thickness (mm). (2) If the thickness of the embossments is not uniform in (1), calculate the area of ​​each embossment by multiplying the length (mm) of the embossment by the thickness (mm), and then add up the areas of all the embossments. (3) The ratio of the embossed area to the area of ​​rectangle E in Figure 3 (length (mm) x width (mm)) is defined as (total embossed area / area of ​​rectangle E) x 100, which is the embossed area ratio (%). (4) If it is difficult to determine the embossed area ratio, the area ratio of the convex portions of the embossing roll used in embossing can be considered as the area of ​​one sheet 10 of paper towel 1x.

[0048] The size of one side of this rectangle E can be changed as appropriate depending on the size of the embossed pattern 12. Furthermore, if an embossed pattern 12 adjacent to an embossed pattern 12 is included within a rectangle that encompasses all of the embossed patterns 12, the length of that adjacent embossed pattern 12 is also measured and included in the total length. If the size of one side of rectangle E cannot be clearly determined by the embossed pattern 12, the size of rectangle E is set to 10 cm x 10 cm, and the total length of the embossments included in this rectangle E is measured. The total length is determined using the method described above.

[0049] (embossing depth) The lower limit of the embossing depth on the front side of the paper towel 1x (hereinafter simply referred to as "embossing depth") is preferably 0.06 mm or more, more preferably 0.10 mm or more, and even more preferably 0.14 mm or more. The upper limit of the embossing depth is preferably 1.05 mm or less, more preferably 0.55 mm or less, and even more preferably 0.35 mm or less. If the embossing depth is less than 0.06 mm, the paper thickness will be low and water absorbency will be poor. If the embossing depth exceeds 1.05 mm, the surface roughness of the back side 1b of the paper towel 1x will be high and the softness of the sheet will be poor.

[0050] The embossing depth is measured using a microscope. The microscope used can be a Keyence Corporation product called the "One-Shot 3D Shape Measuring Instrument VR-3100." The software used to observe, measure, and analyze microscope images can be a Keyence Corporation product called the "Analysis Software VR-H1A." Measurement conditions are a magnification of 25x and a field of view of 12mm x 9mm. The measurement magnification and field of view can be changed as appropriate depending on the desired size of the embossing.

[0051] Figure 5 shows a height profile on the XY plane taken with a microscope, with the height of the surface of the paper towel 1x represented by shading. The linear areas in Figure 5 that are shaded differently from the surrounding area represent individual embossments. The depth of the embossment is determined by measuring the height difference of the embossment using the microscope described above. The measurement is performed on the surface 1a side of the paper towel 1x. Furthermore, when measuring, three wraps of paper towel 1x are removed from the paper towel roll, etc. 1, and the fourth wrap of paper towel 1x is used to measure the product ply in sheet form. Furthermore, if there are perforations 1c, these are avoided when measuring.

[0052] First, a line segment AB is drawn as shown in Figure 5 to obtain the height profile shown in Figure 6. Line segment AB should be drawn across the embossments. Line segment AB is drawn in the width direction (CD) of the paper towel 1x. However, if the spacing between embossments is narrow, e.g., 2 mm or less, and the height of the convex portions described below is low, the line segment may be drawn diagonally or in the machine direction (MD). The height profile is a (measured) cross-sectional curve S that represents the unevenness of the actual paper towel 1x sample surface. However, it also contains noise (steep peaks due to fiber clumps, whisker-like fibers, or fiber-free areas on the surface of the paper towel 1x). Therefore, when calculating the height difference of the unevenness, it is necessary to remove such noise peaks.

[0053] Therefore, the (measured) cross-sectional curve S in Figure 6 was smoothed using the 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 achieved automatically using the analysis software described above. Then, in the graph shown in Figure 7, the average of the maximum values ​​on the vertical axis of the convex portion H1 and the convex portion H2 adjacent to the convex portion H1 was calculated, and the minimum value on the vertical axis of the concave portion D1 sandwiched between the convex portions H1 and H2 was determined. The value obtained by subtracting the minimum value from the average of the maximum values ​​thus obtained was used as the provisional emboss depth. Then, as shown in Figure 7, similar measurements were performed at two consecutive locations on the cross-sectional curve (the concave portion D1 and the concave portion D2 sandwiched between the convex portions H3 and H4) (two consecutive measurement results were obtained at this point). Then, roll 1 is rotated three times by 90 degrees in the direction of the paper towel 1x flow, and the same measurement as above is carried out at each position (for a total of four measurement positions in the direction of the paper towel 1x), and the average value of the total eight positions (2 x 4) is finally adopted as the embossing depth. Note that while visually checking the embossed area in Figure 5, the height profile in Figure 6 is checked to determine the concave and convex areas.

[0054] Note that the paper towel 1x of the present invention has a different concave-convex pattern from the embossed pattern 12, resulting from the papermaking process, and therefore there is variation in the height of the convex portions on either side of the concave portion. Therefore, if the difference in the vertical axis between the convex portions sandwiching the concave portion (for example, convex portions H3 and H4 sandwiching concave portion D2) is 0.2 mm or more, measurements are taken at a location that avoids that portion.

[0055] (Embossed pattern arrangement angle) The arrangement angle of adjacent identical patterns in the embossed pattern 12 (hereinafter also referred to as the "arrangement angle of the embossed pattern") is preferably 20° or more, more preferably 25° or more, and even more preferably 30° or more, relative to the CD direction of the paper towel 1x. It is also preferably 80° or less, more preferably 70° or less, and even more preferably 60° or less. If the arrangement angle of the embossed pattern 12 is less than 20° or more than 80°, the paper towel 1x is prone to wrinkling during processing, resulting in a less soft sheet.

[0056] The arrangement angle of the embossed pattern 12 is measured by the following method. (1) Select one embossment to be used as the measurement standard and determine the reference point of this embossment. For example, as shown in Figure 4, the paper towel 1x is placed so that the MD direction (Y direction) is vertical and the CD direction (X direction) is horizontal. Then, any closed-ring structure embossment 14 in the center of the paper towel 1x is selected, and its center point is set as the reference point 14a. (2) Two embossments adjacent to the reference embossment on the left and right in the CD direction are identified, and measurement points for these embossments are determined. As shown in Figure 4, a straight line passing through reference point 14a and parallel to the CD direction is drawn and designated as reference line 14x. The left closed-ring structure embossment and the right closed-ring structure embossment, which are located above reference line 14x and closest to reference point 14a in the CD direction, are designated as 14B and 14C, respectively, and their center points are designated as measurement points 14b and 14c. (3) Draw an auxiliary line passing through the reference point and the measurement point, and measure the angle between the reference line and the auxiliary line. As shown in Figure 4, an auxiliary line 14y passing through reference point 14a and measurement point 14b, and an auxiliary line 14z passing through reference point 14a and measurement point 14c are drawn. Then, the angle θ1 formed by reference line 14x and auxiliary line 14y, and the angle θ2 formed by reference line 14x and auxiliary line 14z are measured with a protractor and are defined as the arrangement angles. In Figure 4, θ1 is 35° and θ2 is 55°. Note that when θ exceeds 90°, the angle obtained by subtracting θ from 180° is defined as the arrangement angle. For example, when θ is 120°, the angle is defined as 60° (= 180° - 120°).

[0057] (Linear embossed pattern) The embossed pattern 12 preferably has a linear embossed pattern 12. If the embossed pattern 12 is not linear but, for example, dot-shaped, the embossed pattern 12 is easily crushed and has poor water absorbency. Here, a linear embossed pattern 12 refers to one having a width of 0.1 mm to 4 mm and a length of 5 mm or more.

[0058] The proportion of linear embossed portions 12a in the embossed pattern 12 is preferably 20% or more, more preferably 50% or more, and even more preferably 90% or more. If the proportion of linear embossed portions 12a is less than 20%, the water absorbency of the paper towel 1x will be poor.

[0059] The proportion of the linear embossed portion 12a is calculated as follows: First, an arbitrary 100 mm x 100 mm area on the surface of the paper towel 1x on which the embossed pattern 12 is formed is divided into 10 mm squares. Then, the proportion of the linear embossed portion 12a is calculated using the following formula: Proportion (%) of linear embossed portion 12a = (number of squares including linear embossed portion 12a) ÷ (number of squares including linear embossed portion 12a + number of squares including embossments other than linear embossed portion 12a) × 100

[0060] It should be noted that "a square including an embossment other than the linear embossed portion 12a" refers to a square that does not satisfy the conditions of the linear embossed portion 12a among the radial embossment 13 or the closed ring structure embossment 14. In addition, when one square includes both the linear embossment 12a and the dot embossment, the square is considered to be the embossed square with the larger occupancy.

[0061] (Embossed on the back) There is no particular restriction on whether the ply on the back surface 1b of the paper towel 1x has an embossed pattern 12, as long as it has irregularities resulting from the papermaking process that are different from the embossed pattern 12, but it is preferable that the ply has no embossing. If the back surface 1b has an embossing, the surface roughness increases and the softness of the sheet decreases.

[0062] (seat length) The lower limit of the sheet length (length in the Y direction shown in FIG. 1) between adjacent perforations 1c of paper towel 1x is preferably 100 mm or more, more preferably 130 mm or more, and even more preferably 150 mm or more. The upper limit of the sheet length is preferably 250 mm or less, more preferably 230 mm or less, and even more preferably 210 mm or less. If the sheet length is less than 100 mm, the absorbency of paper towel 1x will be poor, and if it exceeds 250 mm, the absorbency of paper towel 1x will be higher than necessary.

[0063] (DMDT) The dry machine direction tensile strength (DMDT) value of the product ply of the paper towel 1x when dry is 2100 cN / 75 mm or more and 6100 cN / 75 mm or less. If the DMDT is less than 2100 cN / 75 mm, the paper towel 1x is prone to tearing, and if it exceeds 6100 cN / 75 mm, the softness of the paper towel 1x is reduced. The lower limit of the DMDT is preferably 2800 cN / 75 mm or more, and more preferably 3600 cN / 75 mm or more. The upper limit is preferably 5450 cN / 75 mm or less, and more preferably 4800 cN / 75 mm or less.

[0064] (DCDT) The dry cross-direction tensile strength (DCDT) value of the product ply of paper towel 1x when dry is 2100 cN / 75 mm or more and 6000 cN / 75 mm or less. If the DCDT is less than 2100 cN / 75 mm, the paper towel 1x is prone to tearing, and if it exceeds 6000 cN / 75 mm, the softness of the paper towel 1x is poor. The lower limit of DCDT is preferably 2800 cN / 75 mm or more, and more preferably 3600 cN / 75 mm or more. The upper limit is preferably 5400 cN / 75 mm or less, and more preferably 4800 cN / 75 mm or less.

[0065] The DMDT and DCDT of paper towel 1x are measured in accordance with JIS P 8113 on the part of paper towel 1x that does not include perforation 1c.

[0066] (Aspect ratio of tensile strength) The ratio of the tensile strength DMDT to the DCDT (= DMDT ÷ DCDT), i.e., the aspect ratio of the tensile strength (hereinafter simply referred to as the "aspect ratio"), is preferably 0.95 or more and 1.30 or less. If the aspect ratio is less than 0.95 or more than 1.30, the softness of the paper towel 1x will be inferior. The lower limit of the aspect ratio is more preferably 0.96 or more, and even more preferably 0.98 or more. The upper limit is more preferably 1.20 or less, and even more preferably 1.10 or less.

[0067] (DMDT / Basm weight) The value obtained by dividing the tensile strength DMDT value by the basis weight per product ply is preferably 41 or more and 95 or less. If this value is less than 41, the paper towel 1x will be easily torn, and if it exceeds 95, the softness of the paper towel 1x will be poor. The lower limit of the value expressed as (DMDT / basis weight) is more preferably 51 or more, and even more preferably 53 or more. The upper limit is more preferably 90 or less, and even more preferably 83 or less.

[0068] (DCDT / Basm weight) The value obtained by dividing the tensile strength DCDT value by the basis weight per product ply is preferably 41 or more and 95 or less. If this value is less than 41, the paper towel 1x will be easily torn, and if it exceeds 95, the softness of the paper towel 1x will be poor. The lower limit of the value expressed as (DCDT / basis weight) is more preferably 51 or more, and even more preferably 53 or more. The upper limit is more preferably 90 or less, and even more preferably 83 or less.

[0069] (Water absorption <unit area>) The water absorption per unit area of ​​1 paper towel (hereinafter simply referred to as "water absorption <unit area>") is 350 g / m 2 More than 810g / m 2 Water absorption <unit area> is 350g / m or less. 2 If the absorbency is less than 810g / m, the absorbency of 1x paper towel will be inferior. 2 If the amount exceeds this, the softness of the paper towel will be reduced and it will be more likely to break when absorbing water. The lower limit of the water absorption capacity (unit area) is 400g / m 2 More than 500g / m 2 More preferably, the upper limit is 750 g / m 2 Preferably less than 660 g / m 2 The following is more preferred:

[0070] (Water absorption <unit mass>) The water absorption per unit mass of the paper towel 1x (hereinafter simply referred to as "water absorption <unit mass>") is preferably 8.0 g / g or more and 13.0 g / g or less. If the water absorption <unit mass> is less than 8.0 g / g, the water absorption of the paper towel 1x will be poor. If the water absorption <unit mass> is more than 13.0 g / g, the softness of the paper towel 1x will be poor and it will be more likely to break when absorbing water. The lower limit of the water absorption <unit mass> is more preferably 8.5 g / g or more, and even more preferably 9.0 g / g or more. The upper limit is more preferably 12.0 g / g or less, and even more preferably 11.3 g / g or less.

[0071] The amount of water absorbed by 1 paper towel in a dry state is measured according to the following method. (1) 1x paper towel stacked in two plies is taken and cut using a square template with one piece measuring 76 mm to prepare a rectangular test piece 20 (see FIG. 8) with one side measuring 76 mm. (2) After measuring the mass of the test piece 20 before water absorption using an electronic balance, the test piece 20 is set in a holder 21 (a jig that fixes three points of the test piece 20, the jig being made of a metal that does not absorb water). (3) Distilled water is poured into a commercially available tray to a depth of 2 cm, and the test piece 20 set in the holder 21 is immersed in the distilled water for 2 minutes. (4) After immersion for 2 minutes, the test piece 20 is removed from the distilled water together with the holder 21, and as shown in Figure 8, the holder 21 and the test piece 20 are hung on a rod placed in an empty water tank with the corner 20a facing up, the lid of the water tank is closed, and the test piece is left for 5 minutes. (5) Then, the holder 21 and the test piece 20 are taken out of the water tank, the holder 21 is removed, and the mass of the test piece 20 is measured using an electronic balance. (6) Water absorption amount <unit area> is calculated from the change in mass of the test piece 20 before and after immersion in distilled water, and is the amount of distilled water absorbed per unit area of ​​the test piece 20 (water g / sheet m 2 , 1m 2 Per. Abbreviated as g / m 2 ) is calculated. (7) Water absorption <unit mass> is the amount of water absorption per unit area (g of water / sheet m 2 ) by the basis weight of the product ply of the test piece 20. Specifically, the water absorption per unit area (water g / sheet m 2 ) ÷ Basis weight (sheet g / sheet m 2 ) = Water absorption <unit mass> (g of water / g of sheet, per 1g. Abbreviated as g / g). (8) Measurements are carried out five times for each sample, and the average value is used.

[0072] If the paper towel 1x is three-ply, it is preferable to measure it as a three-ply towel using the same procedure as for two-ply towels. This measurement is performed in accordance with JIS P 8111 at a temperature of 23±1°C and humidity of 50±2%. The distilled water is kept at 23±1°C.

[0073] <Paper towel rolls, etc.> The paper towel roll or the like 1 obtained by winding the above-mentioned paper towel 1x around a core 1d in a roll shape preferably has the following characteristics.

[0074] <Core (paper tube)> The paper tube (hereinafter also referred to as "core") (1d in Fig. 1) that is present at the center of the paper towel roll or the like 1 and around which the paper towels 1x are wound into a roll is preferably a cylindrical paper tube.

[0075] (Core material) The pulp fibers contained in the base paper of the material (paper) used for the core 1d preferably contain a total of 50% or more, more preferably a total of 70% or more, and even more preferably a total of 90% or more, of softwood bleached kraft pulp (NBKP) and hardwood bleached kraft pulp (LBKP). If the total is 50% or more, the core 1d is less likely to be crushed, but as the total approaches 100%, costs increase.

[0076] Furthermore, the blending ratio of LBKP to the total amount of LBKP and NBKP is preferably 50% or more, more preferably 70% or more, and even more preferably 90% or more. If the blending ratio of LBKP to the total amount of NBKP and LBKP is less than 50%, the cost will be high.

[0077] It is also preferable that the paper used for the core 1d is made of a plurality of overlapping sheets. If the core 1d is made of a single sheet of paper, the core 1d becomes thin and easily crushed. It is preferable that two sheets of paper are overlapped.

[0078] (core mass) The lower limit of the mass of the core 1d is preferably 10 g or more, more preferably 12 g or more, and even more preferably 14 g or more. The upper limit is preferably 25 g or less, more preferably 20 g or less, and even more preferably 17 g or less. If the mass of the core is less than 10 g, the strength of the core is reduced and the roll is prone to crushing during storage. Therefore, it may be necessary to increase the basis weight to compensate for the core strength, resulting in poor softness. If the mass of the core exceeds 25 g, the roll density will decrease when the core diameter is increased, resulting in poor sheet softness.

[0079] (Apparent basis weight of core) The lower limit of the apparent basis weight of the core 1d is 250 g / m 2 More than 300g / m 2 More preferably, 380 g / m 2 More preferably, the upper limit is 650 g / m 2 Preferably less than 520 g / m 2 Less than 450 g / m is more preferable. 2 More preferably, the core 1d has an apparent basis weight of 250 g / m 2 If the apparent basis weight of the core 1d is less than 650 g / m, the core mass will be low when the core outer diameter remains the same, resulting in a low core strength and a need to increase the basis weight of the sheet, resulting in poor softness. 2 If the core thickness exceeds 1d, the cost of the core will be high or the core will be too hard and difficult to cut. The paper used for the core 1d can be calendered.

[0080] The apparent basis weight of the core 1d is expressed as (mass of the core) ÷ (external surface area of ​​the core). The mass and external surface area of ​​the core are the mass and external surface area of ​​the core converted per roll width. For example, if the mass of the core per roll width of 281 mm is 16 g and the outer diameter of the core is 44 mm, the apparent basis weight of the core = 16 ÷ {(3.14 × 44 mm / 1000) × (281 mm / 1000)} = 412 g / m 2Here, core 1d is usually made by gluing two sheets of core base paper together with adhesive or the like, and there are some areas where the two sheets of core base paper overlap, making it thicker, so it is different from a simple sheet rolled up, and therefore the "apparent" basis weight is used.

[0081] (Core outer diameter) The lower limit of the outer diameter of the core 1d (DI shown in FIG. 1) (hereinafter simply referred to as "core outer diameter") is preferably 20 mm or more, more preferably 30 mm or more, and even more preferably 38 mm or more. The upper limit of the core outer diameter is preferably 60 mm or less, more preferably 55 mm or less, and even more preferably 50 mm or less. If the core outer diameter is less than 20 mm, the basis weight may need to be increased to achieve a constant winding diameter of the roll 1, resulting in poor softness. If the core outer diameter exceeds 60 mm, the basis weight may need to be reduced to achieve a constant winding diameter of the roll 1, resulting in poor water absorbency.

[0082] The core outer diameter is measured using a diameter rule manufactured by Muratec KDS Co., Ltd. Three paper towel rolls, etc.1 are measured and the measurement results are averaged.

[0083] (roll diameter) The lower limit of the roll diameter DR of the roll 1 (see FIG. 1) is preferably 130 mm or more, more preferably 135 mm or more, and even more preferably 155 mm or more. The upper limit of the roll diameter DR is preferably 205 mm or less, more preferably 190 mm or less, and even more preferably 170 mm or less. If the roll diameter DR is less than 130 mm, the specific volume will be low and the water absorbency of the paper towel 1x will be poor. If the roll diameter DR exceeds 205 mm, the specific volume will be high, making the sheet more likely to collapse and tear when absorbing water.

[0084] The winding diameter DR of the roll 1 is measured using a diameter rule manufactured by Muratec KDS Co., Ltd. Three rolls 1 are measured, and the measurement results are averaged.

[0085] (Volume length) The winding length of the roll 1 is preferably 18 m or more and 45 m or less. If the winding length is less than 18 m, the absorbency of the paper towel 1x will be poor. If the winding length is more than 45 m, the roll density of the roll 1 will be high and the softness of the paper towel 1x will be poor. The lower limit of the winding length is more preferably 22 m or more, and even more preferably 27 m or more. The upper limit of the winding length is more preferably 40 m or less, and even more preferably 31 m or less.

[0086] The roll length is measured as follows. First, measure the length of 10 sheets of paper towels 1x between perforation 1c on roll 1 and the adjacent perforation 1c. Then, measure the number of sheets on roll 1, and calculate the roll 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 there are 150 sheets, the roll length is 1.80m x (150 / 10) = 27m. Note that if paper towel roll 1 does not have perforation 1c, measure the roll length.

[0087] (winding density) The winding density of roll 1 is 0.15 m / cm 2 More than 0.60m / cm 2 The winding density is preferably 0.15 m / cm or less. 2 Less than or 0.60m / cm 2 If the density exceeds 0.18m / cm, the softness of the paper towel will be reduced. 2 More preferably, 0.20 m / cm or more 2 The upper limit is 0.51 m / cm. 2 Less than 0.43m / cm is more preferable. 2 The following is even more preferred:

[0088] The winding density is expressed as (winding length x number of plies) ÷ (cross-sectional area of ​​the roll). The cross-sectional area of ​​the roll is expressed as {cross-sectional area of ​​the roll outer diameter (winding diameter DR) - (cross-sectional area of ​​the core outer diameter DI)}. For example, in the case of a winding length of 27 m, 2 plies, a winding diameter DR of 150 mm, and a core outer diameter DI of 39 mm, the winding density = (27 m x 2) ÷ {3.14 x (150 mm ÷ 2 ÷ 10) 2 -3.14×(39mm÷2÷10) 2}=0.33m / cm2 This becomes:

[0089] (sheet width) The lower limit of the sheet width (hereinafter also referred to as "roll width") (W shown in FIG. 1) of the paper towel 1x is preferably 200 mm or more, more preferably 220 mm or more, and even more preferably 260 mm or more. The upper limit is preferably 320 mm or less, more preferably 310 mm or less, and even more preferably 290 mm or less. If the sheet width W is less than 200 mm, the absorbency of the paper towel 1x will be poor, and if it exceeds 320 mm, the absorbency of the paper towel 1x will be higher than necessary.

[0090] (Roll mass <without core>) The roll mass of the roll 1 without the core 1d per 280 mm of roll width (hereinafter simply referred to as "roll mass <without core>") is preferably 170 g or more and 700 g or less. If the roll mass <without core> is less than 170 g, the absorbency of the paper towel 1x will be poor. If the roll mass <without core> is more than 700 g, the roll density will be high and the softness of the paper towel 1x will be poor. The lower limit of the roll mass <without core> is more preferably 330 g or more, and even more preferably 430 g or more. The upper limit of the roll mass <without core> is more preferably 600 g or less, and even more preferably 550 g or less.

[0091] Roll mass (without core) is the mass per 280mm of roll width, excluding the core (paper tube) 1d in paper towel rolls, etc. 1. If the roll width is not 280mm, convert to the mass per 280mm by proportional calculation.

[0092] (roll density) The roll density of Roll 1 is 0.050 g / cm 3 More than 0.150g / cm 3 The roll density is preferably 0.050 g / cm or less. 3 If the roll density is less than 0.150 g / cm, the softness of the paper towel will be poor. 3If the density exceeds 0.060 g / cm, the paper towel roll etc. 1 will be tightly wound and the softness of the paper towel 1 will be poor. The lower limit of the roll density is 0.060 g / cm 3 More preferably, 0.070 g / cm or more 3 The upper limit is 0.140 g / cm. 3 Less than 0.095 g / cm is more preferable. 3 The following is even more preferred:

[0093] Roll density is expressed as (roll mass) ÷ (roll volume). Roll mass is the mass of roll 1 per 280 mm of roll width. Roll volume is expressed as [{cross-sectional area of ​​roll outer diameter (winding diameter DR)} - (cross-sectional area of ​​core outer diameter DI)] × roll width (converted per 280 mm). For example, if the roll mass (excluding core) per 280 mm of roll width is 382 g, the winding diameter DR is 150 mm, and the core outer diameter DI is 39 mm, roll density = 382 g ÷ [{3.14 × (150 mm ÷ 2 ÷ 10) 2 -3.14×(39mm÷2÷10) 2}×(280mm÷10)]=0.08g / cm 3 This becomes:

[0094] (Roll softness) The roll softness of roll 1 (hereinafter simply referred to as "roll softness") is preferably 1.2 mm or more and 4.2 mm or less. If the roll softness is less than 1.2 mm, the paper towel roll, etc. 1 will be tightly wound, the sheet will be easily crushed, and the softness of the paper towel 1x will be poor. If the roll softness exceeds 4.2 mm, the paper towel roll, etc. 1 will be easily crushed, the sheet will be crushed, and the water absorbency of the paper towel 1x will be poor. The lower limit of the roll softness is more preferably 1.5 mm or more, and even more preferably 1.8 mm or more. The upper limit is more preferably 3.5 mm or less, and even more preferably 3.0 mm or less. Note that "roll softness" refers to an index of how much the paper towel roll, etc. 1 will be crushed when the side of the paper towel roll, etc. 1 is pressed by hand.

[0095] The softness of the roll 1 is measured using a compression tester (KES-G5 compression tester manufactured by Kato Tech Co., Ltd.) as follows: The direction parallel to the axial direction of the roll 1 is defined as the height direction, and the direction perpendicular to the rotation axis of the roll 1 is defined as the radial direction.

[0096] (1) Place the paper towel roll or the like 1 horizontally on the table of the testing machine so that the axial direction of the roll 1 is horizontal. (2) A KES-G5 compression element (contact area 2.0 cm) was placed at the "axial center" of Roll 1. 2 ) is pressed from above in the radial direction at a speed of 10 mm / min. The "axial center" of roll 1 is determined by measuring the roll width W with a metal ruler or tape measure, and determining the position where the measurement value is 1 / 2, and then pressing the compression element into this position. (3) The pressure with which the compressor presses the roll is 5 gf / cm 2 The indentation depth when the pressure is 150gf / cm 2 The indentation depth at this time is T m As, (T m -T0) is measured as "roll softness". (4) Next, the roll 1 is rotated 90 degrees in the circumferential direction around its axis as the axis of rotation, and the pressing depth T m and T0 are measured, and T m and T0 (T m -T0). (5) For the measurement, three rolls 1 are measured twice (at two angles) as described above, and the average of the six measurement results (= two times / roll x 3 rolls) is taken as the roll softness.

[0097] <Paper towel rolls and other packaging> Preferably, two or three rolls of the above-mentioned paper towel rolls, etc. 1 are lined up and wrapped in film to form a package of paper towel rolls, etc., and more preferably, three rolls are lined up and wrapped in film. Specifically, two or three rolls are lined up adjacent to each other so that the axial directions of the rolls 1 are parallel to each other and wrapped in film. The packaging form may be, for example, caramel packaging or gusset packaging.

[0098] <Manufacturing method for paper towel rolls, etc.> The paper towel roll 1 can be produced, for example, in the following order: (1) papermaking and creping, (2) embossing and adhesive treatment, and (3) roll winding. In the paper towel 1x production (papermaking) process, it is preferable to use the TAD papermaking method.

[0099] In the papermaking process (1), it is preferable that a concave-convex pattern derived from the papermaking process (fabric), different from the above-mentioned embossed pattern, is applied to the paper towel 1x. By having this concave-convex pattern, the water absorption capacity of the paper towel 1x can be further increased.

[0100] "Derived from the papermaking process" means that, during the papermaking process of paper towel 1x, a concave-convex pattern is imparted between the head box 41 of the papermaking machine and the outlet of the Yankee dryer 46. Specifically, in a portion of the papermaking process shown in FIG. 9, pulp slurry 40a is sprayed (supplied) from the head box 41 between the first fabric (forming fabric) 42 and the second fabric (concave-convex fabric) 43, and is drawn onto the second fabric (concave-convex fabric) 43 by the forming roll 44, forming a wet paper 40b. Next, the wet paper 40b is dried together with the second fabric (concave-convex fabric) 43 in a through-air dryer 45, resulting in the formation of concave-convex patterns in the dried sheet 40c. Note that, although FIG. 9 shows the through-air dryer 45 equipped with two units, it may also be equipped with only one unit. Also, although a Yankee hood is depicted on the Yankee dryer 46, the hood may be omitted. Crepe may also be imparted in the Yankee dryer 46.

[0101] The texture pattern can also be changed as needed by changing the fabric pattern (fine pattern, coarse pattern). Selecting a fine pattern reduces water absorption. On the other hand, selecting a coarse pattern increases the paper thickness, resulting in a tighter winding and a less soft sheet. Therefore, balance is important when selecting the texture pattern.

[0102] As described above, according to this embodiment, it is possible to provide a paper towel roll or the like that has good water absorbency, high strength, is tear-resistant, and has a soft texture, even when the paper towel has a high basis weight.

[0103] Although the present invention has been described above using embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. Furthermore, it is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention. [Example]

[0104] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the examples shown below.

[0105] Paper towel rolls of Examples 1 to 14 and Comparative Examples 1 to 6 shown in Tables 1 and 2 were manufactured through the following processes: (1) papermaking and creping, (2) embossing and laminating, and (3) roll winding. The paper towel rolls of all Examples and Comparative Examples were measured for the above-mentioned parameters and evaluated as follows. Note that parameters other than those evaluated below were measured according to the standards or measurement methods described above.

[0106] 1. Absorbency of paper towels A sensory evaluation of the "water absorbency" of manufactured paper towels was conducted by 30 monitors. Three rounds of paper towels were removed from the paper towel roll, and one sheet (sheet length (MD) 180 mm) was cut from the fourth round of paper towels and used to wipe away 40 g of water that had been sprinkled on a table. The monitors evaluated the paper towels using the same method as they normally would, choosing either "the sheet has excellent water absorbency" or "the sheet has poor water absorbency," and the evaluation was made on a four-point scale depending on the number of people who selected "the sheet has poor water absorbency." The evaluation criteria are as follows: ◎: 0-1 people chose "The sheet has poor water absorption" 〇: 2-4 people chose "The sheet has poor water absorption" △: 5-7 people chose "The sheet has poor water absorption" ×: Eight or more people chose "The sheet has poor water absorption."

[0107] 2. Paper towels are hard to tear A sensory evaluation of the "tear resistance" of manufactured paper towels was conducted by 30 monitors. Three rounds of paper towels were removed from a paper towel roll, and one sheet was cut from the fourth round of paper towels and rolled back and forth on a dry table 10 times. The test was conducted with the choice of "the sheet did not tear" or "the sheet tore." The number of people who chose "the sheet tore" was used to evaluate the sheet on a four-point scale. The evaluation criteria are as follows: ◎: 0-1 people selected "The sheet was torn" Yes: 2-4 people selected "The seat was torn" △: 5-7 people selected "The seat was torn" ×: 8 or more people selected "The sheet was torn"

[0108] 3. Paper towels are less likely to tear when absorbing water A sensory evaluation was conducted by 30 monitors to measure the "resistance to tearing when absorbing water" of manufactured paper towels. Three rounds of paper towels were removed from a paper towel roll, and one sheet (180 mm in sheet length (MD)) was cut from the fourth round of paper towels. 40 g of water was sprinkled on a table and used to wipe away the water. The subjects were asked to choose "the sheet did not tear" or "the sheet tore." The number of people who chose "the sheet tore" gave a four-point rating. The evaluation criteria are as follows: ◎: 0-1 people selected "The sheet was torn" Yes: 2-4 people selected "The seat was torn" △: 5-7 people selected "The seat was torn" ×: 8 or more people selected "The sheet was torn"

[0109] 4. Softness of paper towels A sensory evaluation of the "softness" of paper towels after production was conducted by 30 monitors. Three rounds of paper towels were removed from the paper towel roll, and one sheet (180 mm in sheet length (MD)) was cut from the fourth round of paper towels. The panelists were asked to choose between "soft sheet" or "hard sheet," and the number of people who chose "hard sheet" was used to evaluate the sheet on a four-point scale. The evaluation criteria were as follows: ◎: 0-1 people chose "The seat is hard" Yes: 2-4 people chose "The seat is hard" △: 5-7 people chose "The seat is hard" ×: Eight or more people chose "The seat is hard"

[0110] [Table 1]

[0111] [Table 2]

[0112] As is clear from the results shown in Tables 1 and 2, the paper towel rolls, etc. of Examples 1 to 14 were good in water absorbency, tear resistance, tear resistance when absorbing water, and softness. In contrast, the paper towel rolls, etc. of Comparative Examples 1 to 6 were poor in any of water absorbency, tear resistance of the sheet, tear resistance when absorbing water, and softness.

[0113] Therefore, it has been confirmed that the paper towel rolls of the present invention can provide paper towel rolls that have good water absorption, high strength, are resistant to tearing, and have a soft texture, even when they are high-basis weight paper towels. [Explanation of symbols]

[0114] 1: Paper towel rolls, etc. 1a: surface 1b: Back side 1c: Perforation 1d: Core (paper tube) 1e: outermost edge 1x: Paper towel 10: Sheet 11: Irregularities caused by the papermaking process 12: Embossed pattern 12a: Linear embossed part 13: Radial embossing 14: Closed ring structure embossing 14A: Closed ring structure embossed A 14B: Closed ring structure embossed B 14C: Closed ring structure embossed C 14a: Reference point (of closed ring structure embossed A) 14b: Measurement point (of closed ring structure embossment B) 14c: Measurement point (of closed ring structure embossment C) 14x:Reference line 14y, 14z: Auxiliary line 20: Test piece 20a: Corner 21: Holder 40a: Pulp slurry 40b: Wet paper 40c: dry sheet 41: Head box 42: First fabric (forming fabric) 43: Second fabric (textured fabric) 44: Forming roll 45:Through air dryer 46: Yankee Dryer

Claims

1. A paper towel roll or the like in which two to three plies of paper towels are laminated and wound around a core in a roll shape, The paper towels are Basis weight per product ply: 40 g / m ２ 80g / m or more ２ below, The thickness of each product ply is 0.55 mm or more and 1.35 mm or less. Specific volume per product ply is 9.0 cm ３ / g or more 24.0cm ３ / g or less, The tensile strength in the MD direction per product ply when dry based on JIS P 8113 is 2100 cN / 75 mm or more and 6100 cN / 75 mm or less, and the tensile strength in the CD direction per product ply is 2100 cN / 75 mm or more and 6000 cN / 75 mm or less, Water absorption per unit area: 350g / m ２ 810g / m or more ２ Below is the A paper towel roll characterized by:

2. Winding density is 0.15 m / cm ２ 0.60m / cm or more ２ 2. The paper towel roll of claim 1, wherein:

3. 3. The paper towel roll according to claim 1, wherein the water absorption per unit mass of the paper towel is 8.0 g / g or more and 13.0 g / g or less.

4. 3. The paper towel roll of claim 1, wherein the paper towel has a linear embossed pattern.

5. 3. The paper towel roll according to claim 1, wherein the value of the tensile strength DMDT divided by the value of the basis weight per ply of the product is 41 or more and 95 or less.

6. 3. The paper towel roll according to claim 1, wherein the value obtained by dividing the tensile strength DCDT by the basis weight per ply of the product is 41 or more and 95 or less.

7. 3. The paper towel roll according to claim 1, wherein the roll softness is 1.2 mm or more and 4.2 mm or less.

8. Roll density is 0.05 g / cm ３ 0.15g / cm or more ３ 3. The paper towel roll or the like according to claim 1 or 2, wherein:

9. 3. The paper towel roll according to claim 1, wherein the roll length is 18 m or more and 45 m or less.

10. 3. The paper towel roll according to claim 1, wherein the roll mass excluding the core is 170 g or more and 700 g or less.

11. 3. The paper towel roll according to claim 1, wherein the ratio of the tensile strength DMDT to the tensile strength DCDT is 0.95 or greater and 1.30 or less.

Images