Paper towel roll

Abstract

To provide a method for producing a paper towel roll by which the occurrence of paper breakage caused by drying failure in a papermaking process can be suppressed without deteriorating touch feeling, water absorptivity and resistance to breakage.SOLUTION: In the method for producing the paper towel roll by winding a sheet obtained by laminating base papers made by a TAD papermaking machine, the blending ratio of NBKP on the hot air exposure surface of the wet paper is ≥60 mass% and ≤100 mass% and larger than that on the opposite surface, the basis weight of the base paper is ≥15g / m2 and ≤30g / m2, and DMDT / DCDT is ≥0.78 and ≤2.70. There is provided a method for manufacturing a paper towel roll in which DMDT of a paper towel sheet is 2100cN / 76mm or more and 6090cN / 76mm or less, DCDT is 1800cN / 76mm or more and 5560cN / 76mm or less, a water absorption amount per unit area is 250g / or more and / or less, and a water absorption amount per unit mass is / g or more and / g or less. m2 20g 800g 7g m2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to paper towel rolls. [Background technology]

[0002] In recent years, various types of paper towel sheets and paper towel rolls made by rolling up sheets have been developed and sold.

[0003] In such paper towel rolls, the wound paper towel sheets are becoming longer and longer, but high-quality products require not only longer lengths but also other qualities such as aesthetic appeal and water absorbency.

[0004] Among high-end products, paper towel sheets obtained using the so-called TAD (Through Air Drying) papermaking technology (hereinafter also referred to as the "TAD papermaking method"), which uses air drying, are thick sheets with a soft texture and excellent water absorbency.

[0005] Because paper towel sheets made using TAD papermaking technology have the advantages described above, many paper towel rolls sold on the market also use TAD papermaking technology in their manufacturing process.

[0006] As a prior art document relating to paper towel rolls, for example, Patent Document 1 describes a paper towel roll in which sheets with embossed patterns are glued together and laminated into two plies, and the resulting paper towel sheet is wound into a roll. The paper towel sheet has a concave-convex pattern derived from the papermaking process that is different from the embossed pattern, and the basis weight of the two plies is 30 g / m. 2 More than 54g / m 2 The following is a paper thickness of 1.3 mm / 10 sheets or more and 5 mm / 10 sheets or less, 2 ply, 1 m 2 The paper towel roll is characterized by having a water absorption per roll of 220 g to 600 g, a roll length of 14 m to 44 m, and a roll diameter of 110 mm to 189 mm. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2022-116768 Summary of the Invention [Problem to be solved by the invention]

[0008] However, because paper towel sheets made using TAD papermaking technology are bulky and uneven, they have little inter-fiber bonding, making them weak and prone to tearing. Furthermore, if the moisture content of the wet paper in the papermaking process is too high, the strength will be further reduced, which will make the paper more susceptible to breakage during the papermaking process and reduce operability.

[0009] To prevent such problems, it is possible to increase the drying efficiency of the base paper, and possible measures to achieve this include: 1. reducing the basis weight, 2. reducing the beating load on the pulp, and 3. increasing the NBKP content.

[0010] However, measures 1 and 2 further weaken the strength of the base paper, making it more susceptible to breakage and further reducing runnability, while measure 3 makes the strength too high, resulting in a stiff, unattractive texture for the paper towel sheets after production.

[0011] The present invention has been made in consideration of these circumstances, and aims to provide a method for manufacturing paper towel rolls that can suppress paper breaks due to insufficient drying during the papermaking process without compromising texture, water absorbency, or tear resistance. [Means for solving the problem]

[0012] The inventors have conducted extensive research and have found that in a method for manufacturing a paper towel roll, in which an embossed pattern is imparted to at least one ply of base paper made using a TAD papermaking machine, and the resulting two- or three-ply paper towel sheet is wound into a roll, a paper towel roll can be produced that can prevent breaks due to insufficient drying during the papermaking process without compromising texture, absorbency, or tear resistance by using a specified headbox in the papermaking process, setting the NBKP blending ratio on the side of the wet paper that is first hit by the hot air from the TAD within a specified numerical range, specifying the size difference with the opposite side, setting the basis weight and DMDT / DCDT of the base paper within specified numerical ranges, and further setting the DMDT, DCDT, water absorption per unit area, and water absorption per unit mass of the paper towel sheet within specified numerical ranges, thereby solving the above-mentioned problems and leading to the completion of the present invention.

[0013] (1) A first aspect of the present invention is a method for manufacturing a paper towel roll, in which an embossed pattern is imparted to at least one ply of base paper made using a TAD paper machine, and the resulting paper towel sheet is laminated into two or three plies and wound into a roll, wherein in the papermaking process using the TAD paper machine, a headbox is used in which a slurry blowing section is branched into at least two layers, and the blending ratio of softwood bleached kraft pulp (NBKP) on the surface of the wet paper that the hot air from the TAD first hits (hot air exposed surface) is 60% by mass or more and 100% by mass or less, and the blending ratio of the NBKP on the hot air exposed surface of the wet paper is higher than the blending ratio of the NBKP on the surface opposite to the hot air exposed surface, and the basis weight per ply of the base paper is 15 g / m 2 More than 30g / m 2The ratio of the tensile strength in the MD direction when dry per two plies (DMDT) to the tensile strength in the CD direction when dry per two plies (DCDT) (DMDT / DCDT) is 0.78 or more and 2.70 or less, the tensile strength in the MD direction when dry per two plies or three plies of the paper towel sheet (DMDT) is 2100 cN / 76 mm or more and 6090 cN / 76 mm or less, and the tensile strength in the CD direction when dry per two plies (DCDT) is 1800 cN / 76 mm or more and 5560 cN / 76 mm or less, and the water absorption per unit area of ​​the paper towel sheet per two plies or three plies is 250 g / m 2 More than 800g / m 2 and the water absorption per unit mass in the two-ply or three-ply is 7 g / g or more and 20 g / g or less.

[0014] (2) A second aspect of the present invention is a method for manufacturing a paper towel roll as described in (1), characterized in that the NBKP content on the surface of the wet paper opposite the hot air exposure surface is 59 mass% or less.

[0015] (3) A third aspect of the present invention is a method for manufacturing a paper towel roll according to (1) or (2), characterized in that the blending ratio of the NBKP to the hardwood bleached kraft pulp (LBKP) in the entire base paper is NBKP:LBKP = 40-100% by mass: 0-60% by mass.

[0016] (4) A fourth aspect of the present invention is a method for manufacturing a paper towel roll according to (1) or (2), characterized in that in the papermaking process using the TAD papermaking machine, the papermaking speed is 600 m / min or more and 1400 m / min or less.

[0017] (5) A fifth aspect of the present invention is a method for manufacturing a paper towel roll according to (1) or (2), characterized in that the ratio of slurry jet speed to fabric speed (J / W ratio) in the papermaking process is 1.02 or more and 1.12 or less.

[0018] (6) A sixth aspect of the present invention is a method for manufacturing a paper towel roll according to (1) or (2), characterized in that the tensile strength (DMDT) in the MD direction of the base paper per two plies when dry is 1800 cN / 76 mm or more and 5200 cN / 76 mm or less.

[0019] (7) A seventh aspect of the present invention is a method for manufacturing a paper towel roll according to (1) or (2), characterized in that the tensile strength (DCDT) in the CD direction of the base paper per two plies when dry is 1700 cN / 76 mm or more and 5100 cN / 76 mm or less.

[0020] (8) The eighth aspect of the present invention is a method for manufacturing a paper towel roll according to (1) or (2), characterized in that the paper towel sheet has a concave-convex pattern derived from the papermaking process that is different from the embossed pattern.

[0021] (9) A ninth aspect of the present invention is a method for manufacturing a paper towel roll according to (1) or (2), characterized in that the paper towel sheet has a thickness of 2.0 mm / 10 plies or more and 4.5 mm / 10 plies or less.

[0022] (10) A tenth aspect of the present invention is the method for producing a paper towel roll according to (1) or (2), wherein the specific volume of the paper towel sheet is 7 cm 3 / g or more 23cm 3 / g or less. [Effects of the Invention]

[0023] According to the present invention, a method for manufacturing a paper towel roll can be provided that can suppress the occurrence of paper breaks due to insufficient drying during the papermaking process without reducing texture, water absorbency, or tear resistance. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a diagram showing a portion of the papermaking process for the paper towel sheet of the present invention. [Figure 2] FIG. 2 is a diagram showing a cross section of a wet paper in a papermaking process. [Figure 3] FIG. 1 is a diagram showing the relationship between the composition of raw materials for a product and the mechanism by which paper breakage occurs in the papermaking process, together with a moisture content graph. [Figure 4] FIG. 1 is a perspective view of a paper towel roll according to one embodiment of the present invention. [Figure 5] FIG. 2 is a diagram showing an example of an embossed pattern imparted to the sheet in the paper towel roll of the present invention. [Figure 6] FIG. 1 is a diagram showing a method for measuring the water absorption of a paper towel sheet of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] 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.

[0026] Furthermore, the MD direction of a paper towel sheet is the machine direction in which the paper towel sheet flows when it is made, and the CD direction is the direction perpendicular to the MD direction (cross direction).

[0027] <Manufacturing method for paper towel rolls> The manufacturing method of a paper towel roll 1 according to one embodiment of the present invention involves applying an embossed pattern to base paper made using a TAD papermaking machine, laminating the base paper in two or three plies, and winding the resulting paper towel sheet 1x into a roll. The papermaking process using a TAD papermaking machine will be described below.

[0028] 1 shows one embodiment of a papermaking apparatus including a TAD papermaking machine, a feature of the present invention. The papermaking apparatus 110 generally includes a twin fabric forming section 120, a water removal section 140, and a web transfer device 160 disposed between the twin fabric forming section 120 and the water removal section 140.

[0029] First, pulp slurry 104 ejected from a head box 128 is deposited between fabrics 124 and 126, and a paper web (hereinafter also referred to as wet paper) 105 is formed by a forming roll 122. In this case, the head box 128 used has a slurry ejection section that branches into at least two layers.

[0030] Next, the paper web 105 is sent to a dewatering section 170 by fabrics 124 and 126 formed into a continuous loop by a number of guide rolls 130 , and is semi-dewatered by a vacuum (reduced pressure) dewatering device 172 . Either or both of the fabrics 124 and 126 may be wire.

[0031] The paper web 105 is then fed by the fabric 126 and the web transport device 160 to the web imprinting device 180. The web imprinting device 180 is a suction device, such as a multi-slot suction box, that in addition to imprinting the paper web 105, can also force the unsupported portions of the paper web 105 into the holes of the fabric 126 to further dewater the paper web 105.

[0032] The paper web 105 is then sent by the fabric 126 to through-air dryers (TADs) 142a and 142b, which are the first half of the water removal section 140. The through-air dryers 142a and 142b have porous cylinders 144a and 144b and hoods 146a and 146b, respectively, and hot air is blown in the direction of the arrows. The paper web 105 is continuously dried by passing through these through-air dryers 142a and 142b. It is to be noted that only one of the through-air dryers 142a and 142b may be provided.

[0033] Finally, the paper web 105 is sent by the fabric 126 and press roll 132 to the Yankee dryer 150, which is the latter half of the water removal section 140. The paper web 105 is finally dried by the Yankee dryer 150, which has a hood 154, and then creped by a doctor blade 152. The base paper that has undergone the above papermaking processes is then sent to the embossing process and lamination process. Although the hoods 146a and 146b of the through-air dryers 142a and 142b and the hood 154 of the Yankee dryer 150 are arranged in opposite directions in the vertical direction in the papermaking apparatus 110 of Fig. 1, they may be arranged in the same direction. Also, the Yankee dryer 150 does not necessarily need to be provided with the hood 154.

[0034] 2, which shows a cross section of a wet paper 105 in the papermaking process, the blending ratio of softwood bleached kraft pulp (NBKP) on the surface 105a (hot air exposed surface) where the hot air first hits the wet paper 105 is 60% by mass or more and 100% by mass or less. If the blending ratio is less than 60% by mass, drying efficiency will be poor, resulting in paper breaks being more likely to occur in the papermaking process and reduced operability. The lower limit of the blending ratio of NBKP on the hot air exposed surface 105a of the wet paper 105 is preferably 70% by mass or more, and more preferably 80% by mass or more. Furthermore, the blending ratio of NBKP on the hot air exposed surface 105a of the wet paper 105 is higher than the blending ratio of NBKP on the surface 105b opposite the hot air exposed surface. If the blending ratio of NBKP on the hot air exposed surface 105a is lower than the blending ratio of NBKP on the surface 105b opposite the hot air exposed surface, drying efficiency will deteriorate, and as a result, paper breaks will be more likely to occur in the papermaking process, reducing operability.

[0035] Furthermore, the NBKP content on the surface 105b of the wet paper 105 opposite the surface exposed to hot air is preferably 59% by mass or less. If the content exceeds 59% by mass, the strength of the entire base paper increases and the texture deteriorates. Also, there are no particular problems with a content of 0% by mass, but as the content approaches 0% by mass, the drying efficiency decreases and the paper may become more susceptible to breakage during the papermaking process. The lower limit of the NBKP content on the surface 105b opposite to the hot air exposure surface of the wet paper 105 is more preferably 10% by mass or more, and more preferably 20% by mass or more, and the upper limit is more preferably 55% by mass or less, and more preferably 50% by mass or less.

[0036] The NBKP (and LBKP) blending ratio on the hot air exposed surface 105a is the NBKP (and LBKP) blending ratio of the slurry 104 discharged from the head box layer 128a, which is the side closest to the side that is first hit by the hot air when the wet paper 105 is formed, and the NBKP (and LBKP) blending ratio on the surface 105b opposite the hot air exposed surface is the NBKP (and LBKP) blending ratio of the slurry 104 discharged from the head box layer 128b, which is the side farthest from the side that is first hit by the hot air when the wet paper 105 is formed.

[0037] In relation to the blending ratio of NBKP in the wet paper 105 described above, the relationship between the blending ratio of NBKP in the papermaking process and the mechanism by which paper breakage occurs will be described with reference to FIG. In the embodiment shown in Figure 3(a), if NBKP or bleached hardwood kraft pulp (LBKP) is distributed evenly over the entire wet paper (note that in Figures 3(a) to 3(c), dark colors are shown as NBKP and light colors are shown as LBKP, but in Figure 3(a) the overall shading is shown as uniform), the paper will be difficult to dry overall, and paper breaks will occur from the inside and from the surface 105b opposite the surface exposed to hot air. In contrast, in the embodiment shown in Figure 3(b), if NBKP, which dries easily, is distributed on the surface exposed to hot air (Figure 3(b) shows that there is more dark color on the surface exposed to hot air), the inside will dry easily, making paper breaks less likely to occur. On the other hand, in the embodiment shown in Figure 3(c), if LBKP, which is difficult to dry, is placed on the surface exposed to hot air (Figure 3(c) shows that there is a lot of light color on the surface exposed to hot air) (if the proportion of NBKP is reduced), the LBKP will act as a wall, making it difficult for the inside and the surface 105b opposite the surface exposed to hot air to dry, making paper breaks more likely to occur.

[0038] The NBKP to be blended is preferably pulp made from conifers such as fir, pine, cedar, and cypress, while the LBKP is preferably pulp made from hardwoods such as eucalyptus, poplar, acacia, and oak. Recycled pulp (such as waste paper pulp from milk cartons) may also be included.

[0039] Furthermore, in the papermaking process using the TAD papermaking machine (papermaking apparatus 110), the ratio of slurry jet speed to fabric speed (J / W ratio) is preferably 1.02 or more and 1.12 or less. If the J / W ratio is less than 1.02, the DMDT / DCDT ratio, which is the ratio of tensile strengths in the base paper, becomes high, and the paper towel sheet 1x becomes more likely to tear in the CD direction. If the J / W ratio exceeds 1.12, the DMDT / DCDT ratio, which is the ratio of tensile strengths in the base paper, becomes high, and the paper towel sheet 1x becomes more likely to tear in the CD direction. The lower limit of the J / W ratio is more preferably 1.03 or more, and even more preferably 1.04 or more, and the upper limit is more preferably 1.10 or less, and even more preferably 1.08 or less.

[0040] Furthermore, in the papermaking process using the TAD papermaking machine 110, the papermaking speed is preferably 600 m / min or more and 1400 m / min or less. If the papermaking speed is less than 600 m / min, the resulting paper towel sheet 1x will be strong, but will have poor texture. If the papermaking speed exceeds 1400 m / min, the basis weight will be low, making the paper more susceptible to breakage during the papermaking process and reducing operability. Furthermore, if the paper towel sheet 1x is two-ply, the water absorbency will also be poor. The lower limit of the paper speed is preferably 650 m / min or more, and more preferably 700 m / min or more. The upper limit is preferably 1350 m / min or less, and even more preferably 1300 m / min or less. The paper speed in this case refers to the rotation speed of the Yankee dryer 150.

[0041] In the papermaking process, it is preferable that a concave-convex pattern derived from the papermaking process (fabric), which is different from the embossed pattern described below, is applied to the base paper and the paper towel sheet 1x. Without this concave-convex pattern, the water absorbency of the manufactured paper towel sheet 1x will be poor. Note that "originating from the papermaking process" means that, in the papermaking process of the paper towel sheet 1x, an uneven pattern is imparted between the head box 128 of the papermaking machine and the outlet of the Yankee dryer 150. Specifically, in a part of the papermaking apparatus 110 shown in FIG. 1, unevenness can be imparted in a (belt) press section (not shown) disposed between the press roll 132 and the Yankee dryer 150. In the (belt) press section, the paper web 105 and an uneven belt (the uneven belt loops between the (belt) press section and the Yankee dryer 150) are pressed together to impart an uneven pattern to the paper web 105. Note that the uneven belt may be an uneven fabric (wire).

[0042] The uneven pattern can be changed as needed by changing the fabric pattern (fine pattern, coarse pattern). Changing the uneven pattern will change the specific volume (paper thickness), but it is preferable to select a pattern that will keep the specific volume in the rolled state within the above-mentioned numerical range.

[0043] (base paper) The basis weight per ply of the base paper produced from the paper web 105 through the above-mentioned papermaking process is 15 g / m 2 More than 30g / m 2 The basis weight of the base paper is 15 g / m 2 If the base paper has a basis weight of less than 30.0 g / m, the paper tends to break during the papermaking process, reducing the operability. In addition, when the paper towel sheet 1x has two plies, the water absorption is poor. 2 If the strength of the paper towel sheet exceeds this, the strength will increase, but the texture will deteriorate. The minimum basis weight per ply of base paper is 16 g / m 2 It is preferable that the weight is 17 g / m or more. 2 The upper limit is preferably 29 g / m or more. 2 Preferably, it is 28 g / m or less. 2 It is more preferable that the basis weight per ply of the base paper of the paper towel sheet 1x is as follows: The basis weight per ply of the base paper of the paper towel sheet 1x can be measured in accordance with JIS P 8124.

[0044] Furthermore, the tensile strength in the MD direction (DMDT) of each of the two plies of base paper when dry is preferably 1800 cN / 76 mm or more and 5200 cN / 76 mm or less. Similarly, the tensile strength in the CD direction (DCDT) of each of the two plies of base paper when dry is preferably 1700 cN / 76 mm or more and 5100 cN / 76 mm or less. If the DMDT of each of the two plies of base paper is less than 1800 cN / 76 mm or if the DCDT of each of the two plies of base paper is less than 1700 cN / 76 mm, paper breaks are more likely to occur during the papermaking process, reducing operability. Furthermore, the paper towel sheet 1x is more likely to tear. If the DMDT per two plies of base paper exceeds 5200 cN / 76 mm, or the DCDT per two plies of base paper exceeds 5100 cN / 76 mm, the strength of the paper towel sheet 1x increases, but the feel deteriorates.

[0045] The dry machine direction tensile strength (DMDT) of each of the two plies of base paper in the dry MD is preferably 2250 cN / 76 mm or more, more preferably 2650 cN / 76 mm or more, and more preferably 4200 cN / 76 mm or less, more preferably 3800 cN / 76 mm or less. The lower limit of the dry cross direction tensile strength (DCDT) of each of the two plies of base paper in the dry CD direction is preferably 2200 cN / 76 mm or more, more preferably 2600 cN / 76 mm or more, and more preferably 4100 cN / 76 mm or less, and even more preferably 3700 cN / 76 mm or less.

[0046] Furthermore, the ratio of the tensile strength in the MD direction (DMDT) of the base paper per two plies when dry to the tensile strength in the CD direction (DCDT) of the base paper per two plies when dry (DMDT / DCDT) is 0.78 or more and 2.70 or less. If the ratio is less than 0.78, paper breaks tend to occur more easily during the papermaking process, reducing runnability. Furthermore, the paper towel sheet 1x tends to tear more easily. If the ratio exceeds 2.70, and the DMDT is too high, the strength of the paper towel sheet 1x increases, but the texture deteriorates. If the DCDT is too low, paper breaks tend to occur more easily during the papermaking process, reducing runnability. The ratio of DMDT per two plies to DCDT per two plies of base paper (DMDT / DCDT) preferably has a lower limit of 0.82 or more, more preferably 0.86 or more, and an upper limit of 2.10 or less, more preferably 1.85 or less.

[0047] The geometric tensile strength (GMT), which is the square root of the product of DMDT and DCDT per two plies of base paper, preferably has a lower limit of 1749 cN / 76 mm or more, more preferably 2224 cN / 76 mm or more, and even more preferably 2624 cN / 76 mm or more. The upper limit is preferably 5150 cN / 76 mm or less, more preferably 4150 cN / 76 mm or less, and even more preferably 3750 cN / 76 mm or less. If the GMT per two plies of base paper is less than 1749 cN / 76 mm, paper breaks are more likely to occur during the papermaking process, reducing operability. Furthermore, the paper towel sheet 1x is more likely to tear. If the GMT per two plies of base paper exceeds 5150 cN / 76 mm, the strength of the paper towel sheet 1x increases, but the texture deteriorates. The DMDT and DCDT per two plies of base paper are measured in accordance with JIS P 8113. The measurement is performed with two sheets of base paper stacked together (two-ply state). The GMT is calculated as the square root of the product of these tensile strengths.

[0048] The blending ratio of NBKP to LBKP in the entire base paper is preferably NBKP:LBKP = 40-100% by mass:0-60% by mass. If the blending ratio is less than 40% by mass, paper breaks are more likely to occur during the papermaking process, reducing runnability. The paper towel sheet 1x itself also becomes more likely to tear. There is no particular problem with 100% by mass of NBKP, but as the NBKP content approaches 100% by mass, the strength of the paper towel sheet 1x increases, but the texture may deteriorate. The blending ratio of NBKP to LBKP in the entire base paper is more preferably NBKP:LBKP=45-90% by mass:10-55% by mass, and even more preferably 50-80% by mass:20-50% by mass.

[0049] The paper towel roll 1 is manufactured by providing an embossed pattern to at least one ply of base paper having the above characteristics and laminating two or three plies to form a paper towel sheet 1x, which is then wound into a roll. If the manufactured paper towel sheet 1x has fewer than two plies, the absorbency of the paper towel sheet 1x will be poor. If the manufactured paper towel sheet 1x has more than three plies, the strength of the paper towel sheet 1x will be increased, but the texture will be poor.

[0050] <Paper towel roll> Figure 4 is a perspective view of a paper towel roll 1 manufactured by a manufacturing method according to one embodiment of the present invention. As shown in Figure 4, the paper towel roll 1 manufactured by the manufacturing method according to this embodiment is a paper towel roll 1 wound into a roll from a paper towel sheet 1x, which is made by laminating two or three plies of base paper, each ply having an embossed pattern 10 applied to at least one ply. It is preferable that the paper towel sheet 1x has perforations formed in the width direction of the sheet at approximately equal intervals in the winding direction of the roll (not shown). 4, the surface of the paper towel sheet 1x facing the outside of the roll is referred to as surface 1a (surface of the paper towel sheet 1x), and the surface facing the center of the roll is referred to as back surface 1b (back surface of the paper towel sheet 1x). Also, the edge of the paper towel sheet 1x is referred to as the outermost edge 1e of the paper towel roll 1.

[0051] Uses of the 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 to wipe away moisture or oil and remove dirt, as well as rolls of other sanitary paper.

[0052] (winding length and winding diameter) The lower limit of the winding length of the paper towel roll 1 is preferably 18 m or more, more preferably 22 m or more, and even more preferably 25 m or more, and the upper limit is preferably 45 m or less, more preferably 40 m or less, and even more preferably 31 m or less. If the winding length is less than 18 m, the absorbency per roll of the paper towel roll 1 will be poor. If the winding length is more than 45 m, the basis weight will be low if the winding diameter DR remains the same, which will result in paper breaks during the papermaking process and reduced operability. Furthermore, if the paper towel sheet 1x is two-ply, the absorbency will also be poor.

[0053] The roll length is measured as follows. First, measure the length of 10 sheets of paper towel sheets 1x between the perforations on paper towel roll 1. Then, measure the number of sheets on paper towel 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 1.80 m and there are 150 sheets, the roll length is 1.80 m x (150 / 10) = 27 m. If paper towel roll 1 does not have perforations, measure the roll length.

[0054] The lower limit of the winding diameter DR of the paper towel roll 1 according to this embodiment is preferably 130 mm or more, more preferably 135 mm or more, and even more preferably 142 mm or more, and the upper limit is preferably 170 mm or less, more preferably 165 mm or less, and even more preferably 156 mm or less. If the reel diameter DR is less than 130 mm, and the reel length and reel density remain unchanged, the basis weight will be lower, which will result in paper breaks during the papermaking process and reduced operability. Furthermore, if the paper towel sheet 1x is two-ply, the absorbency will also be reduced. If the reel diameter DR exceeds 170 mm, and the reel length and reel density remain unchanged, the basis weight will be higher, which will result in a poorer texture for the paper towel sheet 1x.

[0055] The roll diameter DR 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.

[0056] (sheet width and roll mass) The sheet width (hereinafter also referred to as roll width) of the paper towel roll 1 has a lower limit of preferably 200 mm or more, more preferably 220 mm or more, and even more preferably 260 mm or more, and an upper limit of preferably 340 mm or less, more preferably 320 mm or less, and even more preferably 300 mm or less. If the sheet width is less than 200 mm, the absorbency per sheet of the paper towel sheet 1x will be poor. If the sheet width exceeds 340 mm, the sheet area will be too large, making the paper towel sheet 1x more likely to tear in unintended places.

[0057] The lower limit of the roll mass of the paper towel roll 1 is preferably 240 g or more, more preferably 260 g or more, and even more preferably 280 g or more, and the upper limit is preferably 500 g or less, more preferably 470 g or less, and even more preferably 430 g or less. If the roll mass is less than 240 g, and the winding length remains unchanged, the basis weight will be lower, which will result in paper breaks during the papermaking process and reduced operability. Furthermore, if the paper towel sheet 1x is two-ply, the absorbency will also be reduced. If the roll mass exceeds 500 g, and the winding length remains unchanged, the basis weight will be higher, which will result in a poorer texture for the paper towel sheet 1x.

[0058] The roll mass is the mass per 280mm of sheet width, excluding the paper tube 2 (core) of the paper towel roll 1. If the sheet width is not 280mm, convert it to the mass per 280mm by proportional calculation.

[0059] (roll density) The roll density of the paper towel roll 1 according to this embodiment has a lower limit of 0.04 g / cm 3 It is preferable that the concentration is 0.05 g / cm or more. 3 More preferably, it is 0.06 g / cm or more. 3 The upper limit is more preferably 0.12 g / cm. 3 Preferably, it is 0.11 g / cm or less. 3 More preferably, it is 0.10 g / cm or less. 3 It is more preferable that: Roll density is 0.04g / cm 3 If the roll density is less than 0.12 g / cm, the roll volume remains unchanged, but the basis weight decreases, which leads to increased paper breakage during the papermaking process and reduced operability. Furthermore, the paper towel sheet 1x is more likely to tear, and its water absorbency also decreases. 3 If the volume of the roll does not change, the basis weight will increase instead, resulting in a poor texture for the paper towel sheet 1x.

[0060] Roll density is expressed as (roll mass) ÷ (roll volume). Roll mass is the mass of a paper towel roll 1 per 280 mm of sheet width. Roll volume is expressed as [{cross-sectional area of ​​the roll's outer diameter (winding diameter DR)} - (cross-sectional area of ​​the core's outer diameter DI)] × sheet width (converted per 280 mm). For example, if the roll mass (excluding the core) per 280 mm of sheet width is 382 g, the winding diameter DR is 150 mm, and the core's outer diameter DI is 39 mm, then 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:

[0061] (winding density) The winding density of the paper towel roll 1 according to this embodiment has a lower limit of 0.28 m / cm 2 It is preferable that the thickness is 0.30 m / cm or more. 2 More preferably, it is 0.32 m / cm or more. 2 The upper limit is more preferably 0.45 m / cm. 2 Preferably, it is 0.43 m / cm or less. 2 More preferably, it is 0.41 m / cm or less. 2 It is more preferable that the winding density is 0.28 m / cm or less. 2 If the winding density is less than 0.45 m / cm, the paper towel roll 1 will be wound too loosely, and the paper towel sheet 1x will be easily torn when pressure is applied to the roll during the processing process. 2 If the tension exceeds this value, the paper towel roll 1 is pulled to be tightly wound, which makes the paper more likely to break during the winding process, resulting in reduced operability.

[0062] 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 / cm 2 This becomes:

[0063] (Core outer diameter) Furthermore, the core outer diameter DI, which is the outer diameter of the core (paper tube 2) of the paper towel roll 1 of the present invention, preferably has a lower limit of 20 mm or more, more preferably 30 mm or more, and even more preferably 36 mm or more. The upper limit is preferably 60 mm or less, more preferably 55 mm or less, and even more preferably 52 mm or less. If the core outer diameter DI is less than 20 mm, the paper towel roll 1 will have difficulty rotating in the holder, making the paper towel sheet 1x more likely to tear when pulled during use. If the core outer diameter DI exceeds 60 mm, the winding density will increase if the winding diameter DR remains unchanged, resulting in increased paper breakage and reduced operability.

[0064] The core outer diameter DI 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. If the core does not have a paper tube 2, the diameter of the cavity in the core is measured.

[0065] (core mass) The lower limit of the mass (core mass) of the paper tube 2 of the paper towel roll 1 of the present invention is preferably 10 g or more, more preferably 12 g or more, and even more preferably 14 g or more, and the upper limit is preferably 25 g or less, more preferably 20 g or less, and even more preferably 17 g or less. By having the core mass within the above numerical range, it is possible to produce a paper towel sheet 1x and a paper towel roll 1 that can suppress the occurrence of paper breaks due to poor drying during the papermaking process without compromising texture, absorbency, or tear resistance.

[0066] The core mass of the paper towel roll 1 is the mass of the core (paper tube 2) per 280 mm of sheet width in the paper towel roll 1, and if the sheet width is not 280 mm, it is converted to the mass per 280 mm by proportional calculation. From the viewpoint of strength, the core cardboard tube 2 preferably contains bleached pulp (BKP). The content of BKP in the cardboard tube is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. Similarly, from the viewpoint of strength, the content of LBKP in the BKP contained in the core cardboard tube 2 is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more.

[0067] <Paper towel sheet> The paper towel sheet 1x according to this embodiment preferably contains wet pulp. The wet pulp content is preferably 50% by mass or more. If the wet pulp content is less than 50% by mass, the water absorption capacity of the paper towel sheet 1x decreases. Although there is no particular upper limit for the wet pulp content, if it is too high, the strength of the paper towel sheet 1x tends to increase, which may result in a poor texture. The wet pulp content in the paper towel sheet 1x is more preferably 70% by mass or more, and even more preferably 90% by mass or more. In this case, wet pulp refers to pulp with a moisture content of preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, which is significantly different from the moisture content of dry pulp (about 10% by mass). Wet pulp also includes slush pulp (moisture content of about 95 to 97% by mass).

[0068] (Basic weight) The minimum basis weight per ply of a paper towel sheet is 14.7 g / m 2 It is preferable that the content is 15.7 g / m or more. 2 More preferably, it is 16.6 g / m or more.2 The upper limit is more preferably 29.4 g / m or more. 2 Preferably, it is 28.5 g / m or less. 2 More preferably, it is 27.5 g / m or less. 2 It is more preferable that the basis weight per ply is 14.7 g / m or less. 2 If the basis weight per ply is less than 29.4 g / m, paper breakage occurs easily during the papermaking process of the paper towel sheet 1x, and the operability decreases. Also, if the paper towel sheet 1x is two-ply, the water absorption decreases. 2 If you exceed this limit, the texture of one paper towel sheet will deteriorate. The basis weight per ply of the paper towel sheet 1x can be measured based on JIS P 8124.

[0069] (paper thickness) Furthermore, the paper thickness of the paper towel sheet 1x is preferably 2.0 mm / 10 ply or more and 4.5 mm / 10 ply or less. If the paper thickness is less than 2.0 mm / 10 ply, the absorbency of the paper towel sheet 1x will be poor. If the paper thickness is more than 4.5 mm / 10 ply, the paper towel sheet 1x will be more likely to tear if the basis weight of the paper towel sheet 1x remains unchanged. The thickness of the paper towel sheet 1x is preferably 2.3 mm / 10 plies or more, more preferably 2.6 mm / 10 plies or more, and more preferably 4.2 mm / 10 plies or less, more preferably 4.0 mm / 10 plies or less.

[0070] The thickness of a paper towel sheet 1x can be measured using a thickness gauge (a dial thickness gauge called "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 measuring table, and the gauge reading when the probe is lowered at a speed of 1 mm per second or less. The sample is measured using 10 plies of paper towel sheet 1x (5 sets for 2-ply, 3 sets for 3-ply, and the value is proportionally calculated to 10 plies). The measurement is repeated 10 times at different locations, and the average of the measurement results is used as the final thickness of paper towel sheet 1x.

[0071] (seat length) Furthermore, the sheet length between perforations in the paper towel sheet 1x (the length of the paper towel sheet 1x in the roll winding direction) preferably has a lower limit of 100 mm or more, more preferably 130 mm or more, and even more preferably 150 mm or more. The upper limit is preferably 250 mm or less, more preferably 220 mm or less, and even more preferably 210 mm or less. If the sheet length is less than 100 mm, the water absorbency per sheet of the paper towel sheet 1x will be poor. If the sheet length exceeds 250 mm, the sheet area will be too large, making the paper towel sheet 1x more likely to tear in unintended places. By ensuring that the sheet length is within the above numerical range, a paper towel sheet 1x can be produced that has good texture, absorbency, and tear resistance, and furthermore, a paper towel roll 1 can be produced that can prevent paper breaks due to insufficient drying during the papermaking process.

[0072] (specific volume) The specific volume of one paper towel sheet is 7cm 3 / g or more 23cm 3 / g or less. The specific volume of one paper towel sheet is 7 cm 3 If the specific volume of the paper towel sheet 1x is less than 23 cm3 / g, the water absorbency of the paper towel sheet 1x will be poor. 3 If the paper towel sheet exceeds 1 / g, and the basis weight of 1x paper towel sheet remains unchanged, the paper thickness and specific volume will increase instead, making the sheet more likely to tear. The specific volume of one paper towel sheet is limited to 9 cm 3 / g or more is preferable, and 11cm 3 / g or more is more preferable. The upper limit is 22 cm 3 / g or less, and 3 The specific volume is calculated by dividing the paper thickness per ply of 1x paper towel sheet by the basis weight per ply (the paper thickness per product ply is the basis weight per product ply) to obtain the volume (cm ) per unit (g). 3 )

[0073] (DMDT and DCDT) The dry machine direction tensile strength (DMDT) of the paper towel sheet 1x per two or three plies when dry is 2100 cN / 76 mm or more and 6090 cN / 76 mm or less. If the DMDT is less than 2100 cN / 76 mm, the paper towel sheet 1x itself becomes easily torn. If the DMDT exceeds 6090 cN / 76 mm, the strength of the paper towel sheet 1x increases, but the texture deteriorates. The DMDT per two or three plies of the paper towel sheet 1x has a lower limit of preferably 2600 cN / 76 mm or more, more preferably 3100 cN / 76 mm or more, and an upper limit of preferably 4920 cN / 76 mm or less, more preferably 4450 cN / 76 mm or less.

[0074] Furthermore, the dry cross direction tensile strength (DCDT) of the paper towel sheet 1x per two or three plies when dry is 1800cN / 76mm or more and 5560cN / 76mm or less. If the DCDT is less than 1800cN / 76mm, the paper towel sheet 1x itself becomes more prone to tearing. If the DCDT exceeds 5560cN / 76mm, the strength of the paper towel sheet 1x increases, but the texture deteriorates. The DCDT per two or three plies of the paper towel sheet 1x has a lower limit of preferably 2400 cN / 76 mm or more, more preferably 2800 cN / 76 mm or more, and an upper limit of preferably 4470 cN / 76 mm or less, more preferably 4040 cN / 76 mm or less.

[0075] Furthermore, the ratio (DMDT / DCDT) of the tensile strength in the MD direction of the paper towel sheet 1x when dry per 2 or 3 plies (DMDT) to the tensile strength in the CD direction of the paper towel sheet 1x when dry per 2 or 3 plies (DCDT) is preferably 0.78 or more, more preferably 0.82 or more, and even more preferably 0.86 or more. The upper limit is preferably 2.70 or less, more preferably 2.10 or less, and even more preferably 1.85 or less. If the ratio is less than 0.78, the paper towel sheet 1x itself becomes easily torn. Furthermore, the paper towel sheet 1x becomes easily torn. If the ratio exceeds 2.70, if the DMDT is too high, the strength of the paper towel sheet 1x increases but the texture deteriorates, and if the DCDT is too low, the paper towel sheet 1x itself becomes easily torn. The ratio of DMDT to DCDT (DMDT / DCDT) is calculated as the value per two plies of DCDT when DMDT is used per two plies, and as the value per three plies of DCDT when DMDT is used per three plies.

[0076] The geometric tensile strength (GMT), which is the square root of the product of DMDT and DCDT per 2-ply or 3-ply, preferably has a lower limit of 1944 cN / 76 mm or more, more preferably 2497 cN / 76 mm or more, and even more preferably 2947 cN / 76 mm or more. The upper limit is preferably 5820 cN / 76 mm or less, more preferably 4690 cN / 76 mm or less, and even more preferably 4240 cN / 76 mm or less. If the GMT per 2-ply or 3-ply is less than 1944 cN / 76 mm, the paper towel sheet 1x itself becomes easily torn. If the GMT per 2-ply or 3-ply exceeds 5820 cN / 76 mm, the strength of the paper towel sheet 1x increases, but the texture deteriorates. When the GMT is calculated as per 2-ply DMDT, the DCDT is also calculated as the value per 2-ply, and when the DMDT is calculated as per 3-ply DMDT, the DCDT is also calculated as the value per 3-ply. The DMDT and DCDT for 2-ply or 3-ply paper towel sheets are measured in accordance with JIS P 8113. The GMT is calculated as the square root of the product of these tensile strengths. If the paper towel sheet is 3-ply, the measurement is also performed in accordance with JIS P 8113, but the conditions are changed to 3-ply.

[0077] (Embossed) The paper towel roll 1 (paper towel sheet 1x) of this embodiment is embossed and has an embossed pattern 10. Furthermore, the paper towel sheet 1x of the present invention is embossed into at least one ply, which is then laminated to form two or three plies. When laminating two or three plies, it is preferable to use, for example, ply bond glue to apply the glue and perform the bonding process. By bonding the two or three plies in this way, the plies are bonded together strongly, and the paper towel sheet 1x is less likely to tear or separate even when wet. Furthermore, water may be used instead of ply bond glue, or a mixture of glue and water may be used. If the paper towel sheet 1x has fewer than two plies, the paper towel sheet 1x is prone to wrinkles, resulting in a loss of aesthetic appeal. If the paper towel sheet 1x has more than three plies, the texture of the paper towel sheet 1x deteriorates.

[0078] It is preferable that an embossed pattern 10 be applied to the ply on the surface 1a side of the paper towel sheet 1x. By applying the embossed pattern 10 to the surface 1a side, glue can be applied to the embossed portion and two plies can be laminated together. If the paper towel sheet 1x does not have the embossed pattern 10, the water absorbency of the paper towel sheet 1x will be poor. Also, since ply bond glue will be applied to the entire surface of the paper towel sheet 1x, the texture will be poor.

[0079] FIG. 5 is a diagram showing an example of an embossed pattern 10 in the paper towel roll of this embodiment. It is preferable that the embossed pattern 10 includes radial embossments 11 and closed-ring structure embossments 12, and that the radial embossments 11 and the closed-ring structure embossments 12 are alternately arranged at equal intervals. By including the radial embossments 11 and the closed-ring structure embossments 12 in the embossed pattern 10, it is possible to obtain a paper towel sheet 1x that has excellent texture and water absorbency.

[0080] The overall shape of the radial embossments 11 is not particularly limited, but it is preferable that the embossments have a linear shape extending from the center to the outside or a plurality of embossments in a shape made up of straight lines. When the embossing pattern 10 includes the radial embossments 11, the texture of the paper towel sheet 1x is improved. Like the radial embossments 11, the overall shape of the closed-ring structure embossments 12 is not particularly limited, but it is preferable that the central embossment has a straight line or a figure surrounded by a figure embossment that forms a closed ring on the outside. When the embossment pattern 10 includes the closed-ring structure embossments 12, the water absorbency of the paper towel sheet 1x is improved.

[0081] The embossed pattern 10 includes linear embossed portions 100, and the proportion of linear embossed portions 100 included in the embossed pattern 10 is preferably 20% or more. If the proportion is less than 20%, the embossed pattern 10 cannot contribute to improving the texture and water absorbency, and the paper towel sheet 1x will have poor texture and water absorbency. The proportion of the linear embossed portions 100 contained in the embossed pattern 10 is more preferably 50% or more, and even more preferably 90% or more.

[0082] In this case, the linear embossed portion 100 refers to an embossment having a thickness of 0.1 mm to 4 mm and a length of 5 mm or more. The proportion of the linear embossed portion 100 is determined as follows. First, any 100mm x 100mm area on the surface of the paper towel sheet 1x with the embossed pattern 10 is divided into 10mm squares. Then, the proportion of the linear embossed portion 100 is calculated using the following formula. Note that if a single square contains both linear embossing and dot embossing, the square with the larger embossing occupancy is used. (Number of squares containing linear embossing / Number of squares containing any embossing) x 100 = Percentage of linear embossing in 100 (%)

[0083] The ply on the back surface 1b of the paper towel sheet 1x is not particularly limited as to whether it has the embossed pattern 10, as long as it has a concavo-convex pattern 13 derived from the papermaking process that is different from the embossed pattern 10 described below. Nested embossing or pin-to-pin embossing may be provided, or no embossing may be provided, but nested embossing or no embossing is preferred, and no embossing is more preferred. Furthermore, when the paper towel sheet 1x is three-ply, the ply between the ply on the front surface 1a side and the ply on the back surface 1b side may or may not have an embossed pattern, but it is preferable that the two plies on the front surface have an embossed pattern and the back surface is not embossed.

[0084] (Water absorption) The water absorption per unit area of ​​the paper towel sheet 1x according to this embodiment in 2-ply or 3-ply is 250 g / m 2 More than 800g / m 2 The water absorption per unit area is 250g / m 2 If the thickness is less than 800g / m, the absorbency of the paper towel sheet 1x will be poor. 2 If the basis weight of the paper towel sheet 1x does not change, the paper thickness and specific volume will increase instead, making it more likely to tear. The lower limit of the water absorption per unit area of ​​a 2-ply or 3-ply paper towel sheet is 300 g / m 2 It is preferable that the weight is 350 g / m or more. 2 The upper limit is more preferably 750 g / m or more. 2 Preferably, it is 700 g / m or less. 2 More preferably, it is:

[0085] Furthermore, the water absorption per unit mass of the paper towel sheet 1x in a 2-ply or 3-ply configuration is 7 g / g or more and 20 g / g or less. If the water absorption per unit mass is less than 7 g / g, the water absorption of the paper towel sheet 1x will be poor. If the water absorption per unit mass exceeds 20 g / g, if the basis weight of the paper towel sheet 1x remains unchanged, the paper thickness and specific volume will increase, making the sheet more likely to tear. The water absorption per unit mass of the 2-ply or 3-ply paper towel sheet 1x preferably has a lower limit of 8 g / g or more, more preferably 9 g / g or more, and an upper limit of 18 g / g or less, more preferably 17 g / g or less.

[0086] The method for measuring the amount of water absorption of each paper towel sheet 1x will be described below with reference to FIG. First, a two-ply paper towel sheet 1x is taken and cut using a square template with each side measuring 7.6 cm to prepare a rectangular test piece 20 with each side measuring 7.6 cm. The mass of the test piece 20 before water absorption is measured using an electronic balance. The test piece 20 is set in a holder 21 (a jig that fixes three points of the test piece, made of a metal that does not absorb water).

[0087] Next, 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. 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 6, the holder 21 and the test piece 20 are hung from a rod placed in an empty water tank with the corner 20a facing up, and the lid of the water tank is closed and left for 5 minutes.

[0088] Thereafter, 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 with an electronic balance. From the change in mass of the test piece 20 before and after immersion in distilled water, the amount of distilled water absorbed per unit area of ​​the test piece 20 (g of water / sheet m 2 , 1m 2 Hit. Abbreviated as g / m 2 ) is calculated. Furthermore, the water absorption per unit area (g of water / sheet m 2 ) by the basis weight of the product ply of the test piece 20 to obtain the water absorption per unit area (water g / sheet m 2 ) / basis weight (sheet g / sheet m 2 ) = Water absorption per unit mass (g of water / g of sheet, per 1g. Abbreviated as g / g). Measurements are carried out five times for each sample, and the average value is used.

[0089] When the paper towel sheet 1x is a 3-ply sheet, it is preferable to measure it in the same manner as when it is a 2-ply sheet. This measurement is carried out 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.

[0090] As described above, according to this embodiment, a method for manufacturing a paper towel roll can be provided that can suppress the occurrence of paper breaks due to insufficient drying during the papermaking process without compromising texture, absorbency, or tear resistance.

[0091] 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]

[0092] 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.

[0093] The paper towel rolls of Examples 1 to 13 and Comparative Examples 1 to 5 shown in Tables 3 and 4 were manufactured through the following steps: (1) papermaking and creping, (2) embossing and bonding (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. For each of the following evaluations, 1 point was considered a failure and 2 points or more was considered a pass. Furthermore, each parameter other than the following evaluations was measured according to the standards or measurement methods described above.

[0094] 1. The texture of a paper towel sheet The texture of the paper towel sheets when held in the hand after production was evaluated by 30 monitors, and the number of people who felt that the texture of the sheets was poor was rated on a 4-point scale. The evaluation criteria were as follows: 4: 0-1 people felt that the seat had poor texture 3: 2-4 people felt that the seat had poor texture 2: 5-7 people felt that the seat had poor texture. 1: Eight or more people felt that the seat had poor texture

[0095] 2. Absorbency of paper towel sheets The water absorbency of the paper towel sheets after production was evaluated on a four-point scale based on the amount of water absorbed per unit area and the amount of water absorbed per unit mass, according to the evaluation criteria shown in Table 1 below. [Table 1]

[0096] 3. Paper towel sheets are tear-resistant The tear resistance of the paper towel sheets after production was evaluated using DMDT and DCDT on a four-point scale, according to the evaluation criteria shown in Table 1 below. [Table 2]

[0097] 4. Difficulty in breaking wet paper during the papermaking process (operability) The TAD was used during the production of paper towel rolls, and the reduction in paper breaks was evaluated compared to when equivalent paper towel rolls were produced under other operating conditions. The evaluation was made on a four-point scale based on the "reduction rate of paper breaks per hour." The evaluation criteria were as follows: 4: "Reduction rate of number of paper breaks per hour" is 10% or more 3: "Reduction rate of number of paper breaks per hour" is 5% or more but less than 10% 2: "Reduction rate of number of paper breaks per hour" is 0% or more but less than 5% 1: The "reduction rate of paper breaks per hour" is less than 0% (including cases where it has increased)

[0098] [Table 3]

[0099] [Table 4]

[0100] As is clear from the results shown in Tables 3 and 4, the paper towel rolls of Examples 1 to 13 had good texture, absorbency, and tear resistance in the sheet, and were also less likely to break during the papermaking process. In contrast, Comparative Examples 1 to 5 were all poor in either texture, absorbency, and tear resistance in the sheet, or in tear resistance when wet during the papermaking process. Therefore, it has been confirmed that the paper towel roll manufacturing method of the present invention can provide a paper towel roll manufacturing method that can suppress the occurrence of paper breaks due to poor drying during the papermaking process without compromising texture, absorbency, or tear resistance. [Explanation of symbols]

[0101] 1 paper towel roll 1a surface 1b back side 1e The outermost edge of a paper towel roll 1x Paper Towel Sheet 2 Paper tube 10 Embossing Pattern 11 Radial Embossing 12 Closed ring structure embossing 13 Concave and convex patterns 20 test specimens 20a Corner 21 Holder 100 Linear embossed part 104 Pulp Slurry 105 Paper web (wet paper) 105a Hot air exposed surface 105b The surface opposite to the surface exposed to hot air 110 Paper making equipment 120 Twin Fabric Forming Section 122 Forming Roll 124,126 Fabric 128, 128a, 128b Headbox (Layer) 130 Guide Roll 132 Press Roll 140 Water Removal Section 142a, 142b Through air dryer 144a, 144b Porous cylinder 146a, 146b, 154 Hood 150 Yankee Dryer 152 Doctor Blade 160 Web transfer device 170 Dewatering Section 172 Vacuum (reduced pressure) dehydration equipment 180 Web stamping device

Claims

1. A method for producing a paper towel roll, comprising: providing an embossed pattern to at least one ply of base paper made using a TAD paper machine; laminating the resulting two-ply or three-ply paper towel sheet; and winding the resulting paper towel sheet into a roll; In the papermaking process using the TAD papermaking machine, a headbox is used in which the slurry blowing section is branched into at least two layers, and the blending ratio of softwood bleached kraft pulp (NBKP) on the surface where the hot air from the TAD first hits the wet paper (hot air exposed surface) is 60 mass% or more and 100 mass% or less, and the blending ratio of the NBKP on the hot air exposed surface of the wet paper is higher than the blending ratio of the NBKP on the surface opposite to the hot air exposed surface, The basis weight of one ply of the base paper is 15 g / m ２ 30g / m or more ２ The ratio (DMDT / DCDT) of the tensile strength in the MD direction when dry per two plies to the tensile strength in the CD direction when dry per two plies when dry is 0.78 or more and 2.70 or less, The paper towel sheet has a tensile strength DMDT in the MD direction when dry per 2-ply or 3-ply of 2100 cN / 76 mm or more and 6090 cN / 76 mm or less, and a tensile strength DCDT in the CD direction when dry per 2-ply of 1800 cN / 76 mm or more and 5560 cN / 76 mm or less, The water absorption per unit area of ​​the paper towel sheet in two or three plies is 250 g / m ２ 800g / m or more ２ and the water absorption per unit mass in two or three plies is 7 g / g or more and 20 g / g or less.

2. The method for manufacturing a paper towel roll according to claim 1, wherein the blending ratio of the NBKP on the surface of the wet paper opposite the surface exposed to the hot air is 59% by mass or less.

3. 3. The method for producing a paper towel roll according to claim 1, wherein the blending ratio of the NBKP to the hardwood bleached kraft pulp (LBKP) in the entire base paper is NBKP:LBKP = 40 to 100% by mass: 0 to 60% by mass.

4. 3. The method for manufacturing a paper towel roll according to claim 1, wherein the papermaking speed in the papermaking process using the TAD papermaking machine is 600 m / min or more and 1400 m / min or less.

5. 3. The method for manufacturing a paper towel roll according to claim 1, wherein the ratio of slurry jet speed to fabric speed (J / W ratio) in the papermaking process is 1.02 or more and 1.12 or less.

6. 3. The method for manufacturing a paper towel roll according to claim 1, wherein the tensile strength DMDT of the base paper in the machine direction when dry per two plies is 1800 cN / 76 mm or more and 5200 cN / 76 mm or less.

7. 3. The method for manufacturing a paper towel roll according to claim 1, wherein the tensile strength (DCDT) in the CD direction of the base paper per two plies when dry is 1700 cN / 76 mm or more and 5100 cN / 76 mm or less.

8. The method for manufacturing a paper towel roll according to claim 1 or 2, wherein the paper towel sheet has a concave-convex pattern derived from a papermaking process that is different from the embossed pattern.

9. 3. The method for manufacturing a paper towel roll according to claim 1, wherein the paper towel sheet has a thickness of 2.0 mm / 10 plies or more and 4.5 mm / 10 plies or less.

10. The specific volume of the paper towel sheet is 7 cm ３ / g or more 23cm ３ The method for producing a paper towel roll according to claim 1 or 2, wherein the water content is 1 / g or less.

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