Rolled paper towel and method for producing rolled paper towel

Abstract

To provide a paper towel roll capable of keeping beauty of printing without increasing cleaning of a printing plate even with a paper towel roll where paper towel of high basis weight with excellent functionality in 1 play is wound up in a roll shape, and a manufacturing method for the same.SOLUTION: In a paper towel roll, paper towel of 1 ply which has patterned printing on the surface and is applied with embossment is wound up in a roll shape. A basis weight of the paper towel is between 50 g / m2 and 200 g / m2. In the paper towel roll and a manufacturing method for the same, printing is a nearly projecting segment in a flow direction to an end side of the paper towel whose total length is 10 mm or more, and thickness of a line, of a part of the nearly projecting part, whose parallel distance in the flow direction of the paper towel being away from a straight line connecting both terminals of the segment for 3 mm or more is between 20% and 100% of the thickness of the line of the part other than parts away for 3 mm or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a roll of paper towels and a method for making a roll of paper towels. [Background technology]

[0002] 2. Description of the Related Art In recent years, rolled paper towels, such as hand towel rolls and kitchen towel rolls, made by winding thick paper into a roll, have become commercially available. Among rolled paper towels, those with printed surfaces have good cosmetic properties, and therefore various products have been developed and are commercially available.

[0003] As an example of a prior art document on a technology for printing on the surface of a tissue paper roll, Patent Document 1 describes a sanitary tissue paper roll in which a continuous sheet in which two or more strip-shaped continuous sanitary tissue papers are superimposed is wound into a cylindrical shape, the continuous sheet is embossed and has a pattern printed thereon, the dry tensile strength in the longitudinal direction is 250 to 450 cN / 25 mm width, and the dry tensile strength in the transverse direction is 120 to 190 cN / 25 mm width, the continuous sanitary tissue paper contains 80 to 95% recycled paper pulp, 5 to 20% virgin pulp, and has a basis weight of 12.5 to 14.5 g / m 2 A sanitary tissue paper roll is disclosed, characterized in that [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-069147 A Summary of the Invention [Problem to be solved by the invention]

[0005] Among paper towels, those used as kitchen towels in particular are preferred because they are often used for wiping away water and are reused, and therefore have high water absorption capacity and strength.

[0006] To increase the water absorption of a paper towel and to increase its strength, the basis weight of the paper towel can be increased. However, increasing the basis weight also increases the amount of paper dust, which is more likely to accumulate on the printing plate when printing. If paper dust accumulates on the printing plate, the print will become thicker (larger), and the printing plate will need to be cleaned. On the other hand, making the printing plate thinner will prevent paper dust from accumulating, but the aesthetic quality of the print will be reduced. For this reason, it has been difficult to obtain a one-ply rolled paper towel with a high basis weight and print.

[0007] The present invention has been made in consideration of the above circumstances, and its object is to provide a rolled paper towel and a manufacturing method thereof, which does not require frequent cleaning of the printing plate and can maintain the aesthetic quality of the print in good condition, even if the rolled paper towel is a single-ply high-basis weight paper towel wound into a roll. [Means for solving the problem]

[0008] The inventors conducted extensive research and discovered that, in a rolled paper towel having a patterned print on its surface and one ply of embossing, by specifying the basis weight of the paper towel and setting the line thickness of a specific portion of the print within a prescribed numerical range, it is possible to produce a rolled paper towel that does not require frequent cleaning of the printing plate and can maintain the aesthetic beauty of the print in good condition, thereby solving the above-mentioned problems and leading to the completion of the present invention. Specifically, the present invention provides the following:

[0009] (1) A first aspect of the present invention is a roll-shaped paper towel having a pattern printed on its surface and one ply of embossed paper towel wound into a roll, the paper towel having a basis weight of 50 g / m 2 More than 200g / m 2the print is a line segment having a total length of 10 mm or more and generally convex in the flow direction toward the end side of the paper towel, and the thickness of the line of the generally convex portion at a distance of 3 mm or more parallel to the flow direction of the paper towel from a straight line connecting both ends of the line segment is 20% or more and 100% or less of the thickness of the line of the portion other than the portion at a distance of 3 mm or more. (2) A second aspect of the present invention is a roll-type paper towel as described in (1), characterized in that the paper towel contains synthetic fibers and pulp fibers, the proportion of synthetic fibers in the paper towel being 5% or more and 45% or less, and the proportion of pulp fibers being 55% or more and 95% or less. (3) A third aspect of the present invention is the rolled paper towel according to (2), wherein the synthetic fiber has a basis weight of 8 g / m 2 More than 55g / m 2 and the pulp fiber has a basis weight of 38 g / m 2 More than 160g / m 2 It is characterized in that: (4) A fourth aspect of the present invention is a roll-type paper towel according to any one of (1) to (3), characterized in that the tensile strength in the CD direction (DCDT) of the paper towel when dry is 4 N / 25 mm or more and 80 N / 25 mm or less, and the ratio (DMDT / DCDT) of the tensile strength in the CD direction (DCDT) of the paper towel when dry to the tensile strength in the MD direction (DMDT) of the paper towel when dry is 1.2 or more and 4.5 or less. (5) A fifth aspect of the present invention is a roll-shaped paper towel according to any one of (1) to (4), characterized in that the tensile strength in the machine direction (DMDT) of the paper towel when dry is 15 N / 25 mm or more and 115 N / 25 mm or less. (6) A sixth aspect of the present invention is a rolled paper towel according to any one of (1) to (5), wherein the roll density of the roll is 0.06 g / cm 3 More than 0.19g / cm 3 It is characterized in that: (7) A seventh aspect of the present invention is a roll-shaped paper towel according to any one of (1) to (6), characterized in that the thickness of the paper towel is 0.45 mm or more and 1.8 mm or less. (8) An eighth aspect of the present invention is a roll-type paper towel according to any one of (1) to (7), characterized in that the embossing has a depth of 0.07 mm or more and 2 mm or less. (9) A ninth aspect of the present invention is a roll-shaped paper towel according to any one of (1) to (8), characterized in that the paper towel is a kitchen towel. (10) A tenth aspect of the present invention is a method for producing a rolled paper towel according to any one of (1) to (9), characterized in that the printing speed of the printing is 50 m / min or more and 600 m / min or less. Effect of the Invention

[0010] According to the present invention, a rolled paper towel and a method for producing the same can be provided, which does not require frequent cleaning of the printing plate and can maintain the aesthetic quality of the print in good condition, even if the rolled paper towel is a high-basis weight paper towel that has good functionality in a single ply and is wound into a roll. [Brief description of the drawings]

[0011] [Figure 1] 1 is a perspective view showing an entire roll of paper towels according to the present invention. [Diagram 2] FIG. 2 is an enlarged view of the printed portion of the rolled paper towel of the present invention. [Diagram 3] FIG. 1 is a diagram showing a height profile on an XY plane taken by a microscope using shading. [Figure 4] FIG. 1 is a graph showing a height profile on an XY plane obtained by a microscope. [Diagram 5] FIG. 2 is a diagram showing how to determine the embossing depth for the embossed rolled paper towel of the present invention. [Figure 6]FIG. 2 is a diagram showing a method for measuring the water absorption of the roll-shaped paper towel of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the form for carrying out the present invention (hereinafter, the embodiment) will be described in detail with reference to the drawings. However, these are presented for the purpose of illustration only and are not intended to limit the present invention.

[0013] 1. Rolled paper towels FIG. 1 is a perspective view showing the appearance of a rolled paper towel 1 of the present invention. The rolled paper towel 1 of the present invention is a rolled paper towel 1 having a patterned print 10 on its surface, and one ply of embossed paper towel 1x wound into a roll. The paper towel 1x is preferably perforated in the width direction at equal intervals in the flow direction (not shown). The print 10 is printed in a pattern on the entire paper towel 1x, but FIG. 1 shows an embodiment in which only one line in the width direction is printed for ease of viewing. The paper towel 1x of the present invention can be used as various paper products, and is preferably used as a wiper or kitchen towel, more preferably as a kitchen towel. Also, although the present invention is a paper product used as a wiper or kitchen towel, it may also be used as a nonwoven fabric product.

[0014] As shown in Fig. 1, the surface of the paper towel 1x that faces the outside of the roll is referred to as surface 1a (surface of the paper towel 1x), and the surface that faces the center of the roll is referred to as back surface 1b (back surface of the paper towel 1x). It is preferable that the amount of synthetic fibers contained in the paper towel 1x due to hydroentanglement, which will be described later, is greater on the surface side (i.e., surface 1a side) of the paper towel 1x and less on the back surface 1b side. When printing is performed on the side with a greater amount of synthetic fibers, paper dust is less likely to accumulate on the printing plate, and the cosmetic appearance is also improved.

[0015] (Roll length and diameter) The roll length of the rolled paper towel 1 is 5 m or more and 24 m or less, preferably 7 m or more and 20 m or less, and more preferably 8 m or more and 16 m or less. If the roll length is less than 5 m, the roll length does not exceed a certain level, resulting in poor functionality as a rolled paper towel 1. If the roll length exceeds 24 m, the basis weight of the paper towel 1x decreases instead, resulting in a low water absorption capacity of the paper towel 1x, resulting in poor functionality as a rolled paper towel 1. Furthermore, the roll diameter DR of the rolled paper towel 1 is preferably 105 mm or more and 155 mm or less, more preferably 110 mm or more and 140 mm or less, and even more preferably 115 mm or more and 130 mm or less. If the roll diameter DR is less than 105 mm, the roll length does not exceed a certain level, resulting in poor functionality as a rolled paper towel 1. If the roll diameter DR exceeds 155 mm, the rolled paper towel 1 is too large and difficult to use, resulting in poor functionality as a rolled paper towel 1.

[0016] The roll length is measured by measuring the length of 10 pieces of paper towels 1x between the perforations of the rolled paper towels 1. After that, the number of paper towels 1x in the rolled paper towels 1 is measured, and the roll length is calculated by proportional calculation from the length of 10 pieces and the number of paper towels 1x. For example, if the length of 10 pieces is 1.80 m and the number of paper towels 1x is 150, the roll length is 1.80 m x (150 / 10) = 27 m. If the rolled paper towels 1 do not have perforations, the roll length can be measured by actual measurement. The roll diameter DR is measured using a diameter rule manufactured by Muratec KDS Co., Ltd. The measurement is performed by measuring 10 rolled paper towels 1, and the measurement results are averaged. Furthermore, the length between the perforations (the length of the paper towel 1x in the flow direction) is preferably 110 mm to 360 mm, more preferably 160 mm to 310 mm, and even more preferably 210 mm to 260 mm. By keeping it within this range, when using a rolled paper towel 1 with a high water absorption capacity (high basis weight) as in the present application, the area used is appropriate and a large amount of water can be absorbed.

[0017] (Roll width and roll weight) The roll width of the rolled paper towel 1 is preferably 150 mm to 380 mm, more preferably 200 mm to 350 mm, and even more preferably 250 mm to 300 mm. By setting the roll width within this range, when using a rolled paper towel 1 with a high water absorption capacity (high basis weight) as in the present application, the area used is appropriate and a large amount of water can be absorbed. The roll weight of the rolled paper towel 1 is preferably 170 g to 460 g, more preferably 250 g to 410 g, and even more preferably 280 g to 360 g. If the roll weight is less than 170 g, the wound length will not be constant, and the function of the rolled paper towel 1 will be inferior. If the roll weight exceeds 460 g, the basis weight of the paper towel 1x will be high, and as a result, paper powder will easily accumulate on the printing plate, and the printing plate will need to be washed more frequently. The roll mass is the mass of one roll per 275 mm of roll width, not including the core (paper tube). If the roll width is not 275 mm, it is converted to the mass per 275 mm by proportional calculation.

[0018] (Core outer diameter) Furthermore, the core outer diameter DI, which is the outer diameter of the core of the rolled paper towel 1 of the present invention, is preferably 30 mm or more and 60 mm or less, more preferably 34 mm or more and 55 mm or less, and even more preferably 37 mm or more and 50 mm or less. If the core outer diameter DI is less than 30 mm, when the rolled paper towel 1 is formed, the core is too small and difficult to use, and the function of the rolled paper towel 1 is inferior. If the core outer diameter DI exceeds 60 mm, when the rolled paper towel 1 is formed, the core is too large and difficult to use, and the function of the rolled paper towel 1 is inferior. The core outer diameter DI is measured using a diameter rule manufactured by Muratec KDS Co., Ltd. Ten rolled paper towels 1 are measured, and the measurement results are averaged.

[0019] (Roll density) The roll density of rolled paper towel 1 is 0.06 g / cm 3 More than 0.19g / cm 3 It is preferable that the concentration is 0.09 g / cm or less. 3 More than 0.17g / cm 3 More preferably, it is 0.11 g / cm or less. 3 More than 0.15g / cm 3 It is more preferable that the roll density of the rolled paper towel 1 is 0.06 g / cm or less. 3 If the roll density of the rolled paper towel 1 is less than 0.19 g / cm, the embossing may become too deep when embossing is performed after printing, causing the printed portion to break, resulting in poor cosmetic appearance of the printed portion and poor functionality as the rolled paper towel 1. 3 If it exceeds this value, the embossing will be shallow and the wiping properties will be poor, resulting in poor functionality as the rolled paper towel 1.

[0020] The roll density is expressed as (roll mass) ÷ (roll volume). The roll mass is the mass of the rolled paper towel 1 per 275 mm of roll width. The roll volume is expressed as [{cross-sectional area of ​​the roll outer diameter (winding diameter DR)} - (cross-sectional area of ​​the core outer diameter)] x roll width (converted per 275 mm). For example, if the roll mass (excluding the core) per 275 mm of roll width is 337 g, the winding diameter is 119 mm, and the core outer diameter is 49 mm, the roll density = 0.13 g / cm 3 In addition, if rolled paper towel 1 does not have a core, the diameter of the central hole is taken as the core outer diameter DI.

[0021] 2. Paper towels The paper towel 1x of the present invention preferably contains synthetic fibers and pulp fibers. Examples of synthetic fibers include nylon, vinylon, polyester, acrylic, polyethylene, polypropylene, polystyrene, etc., but in order to obtain a paper towel 1x with a high basis weight and a predetermined print as in the present invention, polyethylene and polypropylene are preferred, and polypropylene is more preferred. There is no restriction on the nonwoven fabric used as the synthetic fiber, but spunbond nonwoven fabric is preferred. By using a spunbond nonwoven fabric of polypropylene, even if printing is performed on a paper towel with a high basis weight as in the present application, paper dust is less likely to accumulate on the printing plate, and the aesthetic quality of the print is also improved. In addition, the function as a roll-shaped paper towel 1 is also improved. In addition, general pulp fibers such as softwood bleached kraft pulp (NBKP) and hardwood bleached kraft pulp (LBKP) can be used as the pulp fiber. The content ratio of NBKP and LBKP in the pulp fiber is preferably NBKP:LBKP=50:50 to 100:0, more preferably NBKP:LBKP=70:30 to 100:0, further preferably NBKP:LBKP=90:10 to 100:0, and most preferably NBKP:LBKP=100:0. As the NBKP, for example, fibers made of radiata pine, slash pine, southern pine, lodgepole pine, spruce, and Douglas fir are preferable. Note that NUKP can be used instead of NBKP, and LUKP can be used instead of LBKP. In this case, the proportion (content) of synthetic fibers in the paper towel 1x is preferably 5% to 45%, more preferably 9% to 38%, and even more preferably 12% to 28%. If the proportion of synthetic fibers is less than 5%, paper dust tends to accumulate on the printing plate, and the printing plate needs to be washed more frequently. If the proportion of synthetic fibers exceeds 45%, the water absorption capacity of the paper towel 1x is poor, and as a result, the function as a roll-shaped paper towel 1 is poor. Furthermore, the proportion (content) of pulp fibers in the paper towel 1x is preferably 55% to 95%, more preferably 62% to 91%, and even more preferably 72% to 88%. If the proportion of pulp fibers is less than 55%, the water absorption capacity of the paper towel 1x will be poor, and as a result, the functionality as a roll-shaped paper towel 1 will be poor. If the proportion of pulp fibers exceeds 95%, paper dust will easily accumulate on the printing plate, and the frequency of washing the printing plate will increase (become more frequent).

[0022] Furthermore, the paper towel 1x preferably contains a general wet strength agent. The content of the wet strength agent (in terms of solids (active ingredients)) is preferably 0.05% to 1.0% of the pulp fiber (bone dry), more preferably 0.10% to 0.50%, and even more preferably 0.20% to 0.40%. By keeping the content of the wet strength agent within the above numerical range, a rolled paper towel 1 having a high basis weight and a predetermined print, as in the present application, can be obtained. If necessary, the paper towel 1x may contain a heat stabilizer, a lubricant, etc., within the scope of the present invention. Examples of heat stabilizers include phenolic stabilizers such as BHT (2,6-di-t-butyl-4-methylphenol).

[0023] (Basic weight) The basis weight of one paper towel is 50 g / m 2 More than 200g / m 2 60 g / m 2 More than 170g / m 2 It is preferable that the thickness is less than 100 g / m 2 More than 140g / m 2 It is more preferable that the basis weight of one paper towel is 50 g / m or less. 2 If the basis weight of the paper towel 1x is less than 200 g / m, the paper towel 1x may be easily torn or may have a reduced water absorption capacity, resulting in poor functionality of the rolled paper towel 1. 2 If the printing plate exceeds this limit, paper dust will easily accumulate on the plate, and the plate will need to be cleaned more frequently.

[0024] In addition, when the paper towel 1x contains synthetic fibers and pulp fibers as described above, the basis weight of the synthetic fibers contained in the paper towel 1x is 8 g / m 2 More than 55g / m 2 It is preferable that the thickness is less than 12 g / m 2 More than 45g / m 2 More preferably, it is 15 g / m or less. 2 More than 38g / m 2 It is more preferable that the synthetic fiber has a basis weight of 8 g / m or less. 2 If the weight is less than 55g / m, paper dust will easily accumulate on the printing plate, and the printing plate will need to be washed more frequently. 2 If it exceeds this value, the water absorption capacity of the paper towel 1x will be inferior, and as a result, the function of the rolled paper towel 1 will be inferior. Furthermore, the basis weight of the pulp fiber in one paper towel is 38 g / m 2 More than 160g / m 2 It is preferable that the thickness is less than 45 g / m 2 More than 140g / m 2 More preferably, it is 60 g / m or less. 2 More than 120g / m 2 It is more preferable that the basis weight of the pulp fiber is 38 g / m or less. 2 If the basis weight of the pulp fiber is less than 160 g / m, the water absorption capacity of the paper towel 1x will be poor, and as a result, the function of the rolled paper towel 1 will be poor. 2 If the printing plate exceeds this limit, paper dust will easily accumulate on the plate, and the plate will need to be cleaned more frequently. The basis weight of the paper towel 1x is measured in accordance with JIS P 8124. However, since it is difficult to measure the basis weight of the synthetic fiber and the pulp fiber individually after the hydroentanglement described below, they are measured, for example, by the following method.

[0025] First, prepare a 0.1M aqueous solution of acetic acid and a 0.1M aqueous solution of sodium acetate. Mix about 830g of the 0.1M aqueous solution of acetic acid and about 160g of the 0.1M aqueous solution of sodium acetate to make the pH 4, and use this as an acetate buffer. Add Cellulase Onozuka p1500 (manufactured by Yakult Pharmaceutical Co., Ltd.) to this acetate buffer so that the amount added is 1 wt%. 50 ml of acetate buffer containing Cellulase Onozuka P1500 and 0.5 g of 1x paper towel are placed in a vial and tightly capped. After shaking at 180 rpm and 40°C for 24 hours, the synthetic fiber is taken from the vial and the mass of the synthetic fiber is measured. The basis weights of the synthetic fiber and pulp fiber are calculated from the mass (0.5 g) of 1x paper towel (including synthetic fiber and pulp fiber) and the mass of the collected synthetic fiber using the following formula. Synthetic fiber basis weight = Basis weight of 1x paper towel x (mass of synthetic fiber / mass of 1x paper towel) Pulp fiber basis weight = Basis weight of 1x paper towel × [(mass of 1x paper towel – mass of synthetic fiber) / mass of 1x paper towel]

[0026] Furthermore, if it is difficult to measure using the above method, the basis weight is calculated as follows: basis weight of paper towel 1x measured according to JIS P 8124 - basis weight of synthetic fiber used = basis weight of pulp fiber; however, since the basis weights of the raw roll (base paper) after hydroentanglement and the embossed paper towel 1x differ (the basis weight is lower after embossing), the final basis weights of the synthetic fiber and pulp fiber are determined by making the following corrections. For example, the basis weight of synthetic fibers is 26 g / m 2 The basis weight of the base paper after hydroentanglement is 128 g / m 2 , the basis weight of one paper towel after embossing is 125g / m 2 In this case, the basis weight of the synthetic fiber is 26×125 / 128=25g / m 2 , the basis weight of pulp fiber is 125-25=100g / m 2 Let us assume that.

[0027] (Paper thickness and specific volume) The thickness of the paper towel 1x is preferably 0.45 mm or more and 1.8 mm or less, more preferably 0.55 mm or more and 1.45 mm or less, and even more preferably 0.75 mm or more and 1.2 mm or less. If the thickness is less than 0.45 mm, the water absorption of the paper towel 1x is poor, and as a result, the function as a roll-shaped paper towel 1 is poor. If the thickness exceeds 1.8 mm, paper powder is likely to accumulate on the printing plate, so the frequency of cleaning the printing plate increases (more frequently). The paper thickness is measured using a thickness gauge (dial thickness gauge "PEACOCK" manufactured by Ozaki Manufacturing Co., Ltd.). The measurement conditions are a measurement load of 3.7 kPa, a measuring probe diameter of 30 mm, a sample is placed between the measuring probe and the measuring table, and the gauge is read when the measuring probe is lowered at a speed of 1 mm or less per second. The measurement is repeated 10 times and the measurement results are averaged. The measurement is performed by stacking three paper towels 1x and measuring the value, which is 1 / 3 of the value, to obtain the paper thickness value. Also, the specific volume of one paper towel is 5 cm 3 / g or more 15cm 3 / g or less, and 3 / g or more 13cm 3 / g or less is more preferable, and 3 / g or more 11cm 3 / g or less. 3 If the specific volume is less than 15 cm3 / g, the water absorption capacity of the paper towel 1x is poor, and as a result, the function of the rolled paper towel 1 is poor. 3 If the density exceeds 100 / g, paper dust will easily accumulate on the printing plate, and the frequency of cleaning the printing plate will increase. The specific volume is calculated by dividing the thickness of 1x paper towel by the basis weight, and expressing the volume cm per unit g. 3 It is expressed as:

[0028] (printing) Figure 2 is an enlarged view of the print 10 portion of the rolled paper towel 1. As shown in Figure 2, the print 10 is a line segment 10a with a total length of 10 mm or more and substantially convex in the flow direction toward the end of the paper towel 1x (the end edge 1e of the outermost roll of the paper towel 1x). Note that while the substantially convex portion is substantially at a right angle in Figures 1 and 2, it may be substantially arc-shaped or substantially rectangular as long as the distance T parallel to the flow direction, which will be described later, is 3 mm or more. In the substantially convex portion, the line thickness of the portion 10d that is 3 mm or more away from the straight line 10c connecting both ends 10b of the line segment 10a in the direction parallel to the flow of the paper towel 1x is 20% to 100% of the line thickness of the portion 10e other than the portion 10d that is 3 mm or more away, preferably 35% to 95%, and more preferably 50% to 90%. If it is less than 20%, 10d becomes too thin, resulting in poor aesthetic appearance of the print. If it exceeds 100%, paper dust tends to accumulate on the printing plate (especially the printing plate in the 10d portion), so the frequency of washing the printing plate increases (increases). By setting the ratio of the line thickness of 10d to the line thickness of 10e within the above numerical range, the printing plate in the 10d portion becomes thinner than the printing plate in the 10e portion, so that paper dust is less likely to accumulate, and the frequency of washing the printing plate does not increase, and the aesthetic appearance of the print can be maintained. In this case, the thickness of the line 10d is the thickness of one point (the roughly convex convex portion) of the 10d part, and the thickness of the line 10e is the average of the line thicknesses of the central part in the flow direction at T of the 10e part (two points in the case of Figure 2).

[0029] (Embossed) The rolled paper towel 1 (paper towel 1x) of the present invention is embossed, and is preferably embossed by a roll winder. The shape of the embossed portion may be any shape, including a circle, an ellipse, a rectangle, a square, a floral pattern, a polygon, a letter, a line, a logo, etc., without any particular limitations. To obtain a paper towel 1x with a high basis weight and a predetermined embossing as in the present invention, a hexagonal shape is preferred. The embossing depth is preferably 0.07 mm to 2 mm, more preferably 0.3 mm to 1.5 mm, and even more preferably 0.5 mm to 1.0 mm. If the embossing depth is less than 0.07 mm, the unevenness of the embossing will be small (shallow), resulting in poor wiping properties and poor functionality as the rolled paper towel 1. If the depth exceeds 2 mm, the embossing will be deep when providing the embossing after printing, which may cause the printed portion to tear, resulting in poor functionality as the rolled paper towel 1.

[0030] The depth of the embossing is measured using a microscope. As a microscope, a product name "One Shot 3D Measuring Macroscope VR-3100" manufactured by KEYENCE Corporation can be used. As software for observing, measuring, and analyzing microscope images, a product name "VR-H1A" can be used. The measurement conditions are a magnification of 12 times and a field of view area of ​​24 mm x 18 mm. The measurement magnification and field of view area may be changed as appropriate depending on the desired size of the embossing.

[0031] FIG. 3 shows a height profile on the XY plane taken by a microscope, and the height of the surface of the paper towel is represented by shading. The hexagonal shaped areas in FIG. 3, which are shaded differently from the surrounding areas, represent individual embossments. The depth of the embossment is determined by measuring the height difference of the embossment using the microscope. The measurement is performed on the surface 1a side of the paper towel 1x. When measuring, three turns of the paper towel 1x are removed from the rolled paper towel 1, and the fourth turn of the paper towel 1x is used to measure the paper towel in its state. If there are perforations or printed areas, these are avoided during the measurement. First, a line segment AB is drawn as shown in FIG. 3 to obtain a height profile as shown in FIG. 4. The line segment AB may be drawn so as to cross the embossments. The line segment AB is drawn in the width direction (CD direction) of the paper towel 1x, but if the distance between the embossments is, for example, 2 mm or more, the line segment may be drawn diagonally or in the flow direction. The height profile is a (measured) cross-sectional curve S that represents the unevenness of the actual sample surface of the paper towel 1x, but it also includes noise (steep peaks due to fiber clumps on the surface of the paper towel 1x, fibers that grow in whiskers, and areas without fibers), and it is necessary to remove such noise peaks when calculating the height difference of the unevenness. Therefore, the (measured) cross-sectional curve S in FIG. 4 is smoothed by setting the filter size of the weighted average radio button to ±12 to obtain the cross-sectional curve W in FIG. 5. The smoothing using the filter of the weighted average radio button can be obtained automatically by using the above-mentioned analysis software. Then, in the graph shown in FIG. 5, the average value of the maximum values ​​on the vertical axis of the graph of the convex part H1 and the convex part H2 adjacent to the convex part H1 is calculated, and the minimum value on the vertical axis of the concave part D1 sandwiched between the convex parts H1 and H2 is obtained. The value obtained by subtracting the minimum value from the average value of the maximum values ​​thus obtained is set as the provisional emboss depth. Then, as shown in FIG. 5, the same measurement is performed on a total of two consecutive locations on the cross-sectional curve (a total of two consecutive locations of the concave part D1 and the concave part D2 sandwiched between the convex parts H2 and H3) (two measurement results are obtained at this point). Then, the roll of paper towel 1 is rotated 90 degrees three times in the flow direction of the paper towel 1x, and the same measurement as above is taken at each position (a total of four measurement positions in the flow direction), and the average value of the total of eight positions (2 x 4) is ultimately adopted as the embossing depth.

[0032] (Water absorption) In the present invention, 1m of paper towel 1x 2 The water absorption per m is preferably 270 g to 600 g, more preferably 310 g to 560 g, and even more preferably 360 g to 490 g. 2If the water absorption capacity per unit area is less than 270 g, the water absorption capacity of the paper towel 1x is inferior, and as a result, the function of the rolled paper towel 1 is inferior. 2 If the water absorption per unit exceeds 600g, paper dust will tend to accumulate on the printing plate, and the frequency of cleaning of the printing plate will increase (or become more frequent). Furthermore, the water absorption per gram of the paper towel 1x is preferably 2.5 g to 5.7 g, more preferably 2.9 g to 5.3 g, and even more preferably 3.3 g to 4.8 g. If the water absorption per gram is less than 2.5 g, the water absorption of the paper towel 1x will be poor, and as a result, the function of the rolled paper towel 1 will be poor. The water absorption of each paper towel is measured as follows.

[0033] First, a paper towel 1x is taken and cut using a square template with each piece being 7.6 cm (3 inches) to prepare a rectangular test piece 200 with each side being 7.6 cm. Thereafter, the mass of the test piece 200 before water absorption is measured using an electronic balance. Then, the test piece 200 is set in a holder 220 (a jig that fixes three points of the test piece 200, the jig being made of a metal that does not absorb water). Next, distilled water is poured into a commercially available tray to a depth of 2 cm, and the test piece 200 set in the holder 220 is immersed in the distilled water for 2 minutes. After immersion for 2 minutes, the test piece 200 is taken out of the distilled water together with the holder 220, and a band 210 is attached to one corner 200d of the test piece 200 as shown in FIG. 6. The band 210 is made by cutting the same paper towel 1x as the sample to be measured into a size of 2 mm wide x 15 mm long, and attaching it to a part 6 mm from the corner 200d of the test piece 200 toward the center. Next, the holder 220 and the test piece 200 are hung on a rod installed in an empty water tank so that the corner 200a facing the corner 200d is on top, and the lid of the water tank is closed and left for 10 minutes. Thereafter, the holder 220 and the test piece 200 are taken out of the water tank, the band 210 and the holder 220 are removed, and the mass of the test piece 200 is measured with an electronic balance. From the change in mass of the test piece 200 before and after immersion in distilled water, 2 Water absorption per unit (g(water) / m 2(paper towels). In addition, 1m 2 Water absorption per unit (g(water) / m 2 (Paper towel)) by the basis weight of 200 test pieces to obtain 1 m 2 Water absorption per unit (g(water) / m 2 (Paper towel) / grammage(g(Paper towel) / m 2 Calculate the amount of water absorbed per gram (g (water) / g (paper towel)) = the amount of water absorbed per gram (g (water) / g (paper towel)). Measurements are carried out five times for each sample, and the average value is used. This measurement is performed according to JIS P 8111 at a temperature of 23±1°C and a humidity of 50±2%. The distilled water is kept at 23±1°C.

[0034] (DMDT and DCDT) The tensile strength in the MD direction of the paper towel 1x when dry based on JIS P 8113 (DMDT) is preferably 15N / 25mm or more and 115N / 25mm or less, more preferably 20N / 25mm or more and 100N / 25mm or less, and even more preferably 35N / 25mm or more and 80N / 25mm or less. The tensile strength in the CD direction (DCDT) when dry is preferably 4N / 25mm or more and 80N / 25mm or less, more preferably 6N / 25mm or more and 65N / 25mm or less, and even more preferably 10N / 25mm or more and 50N / 25mm or less. If the DMDT is less than 15N / 25mm or the DCDT is less than 4N / 25mm, paper powder tends to accumulate on the printing plate, and the frequency of washing the printing plate increases (increases). If the DMDT exceeds 115 N / 25 mm or the DCDT exceeds 80 N / 25 mm, the strength of the paper towel 1x is low and the function as the rolled paper towel 1 is inferior. In this case, the MD direction and the CD direction are such that the manufacturing direction (flow direction) of the paper towel 1x during manufacturing is the MD direction, and the CD direction is a direction perpendicular to the MD direction.

[0035] Furthermore, the ratio (DMDT / DCDT) of the tensile strength in the MD direction when dry (DMDT) to the tensile strength in the CD direction when dry (DCDT) of the paper towel 1x is preferably 1.2 to 4.5, more preferably 1.4 to 4.0, and even more preferably 1.6 to 3.5. If the ratio exceeds 4.5, the DCDT will be low and the paper towel 1x will be prone to tearing or tearing during printing, resulting in poor functionality as a rolled paper towel 1.

[0036] (WMDT and WCDT) The tensile strength in the MD direction of the paper towel 1x when wet based on the old JIS S 3104 (WMDT) is preferably 13N / 25mm or more and 100N / 25mm or less, more preferably 18N / 25mm or more and 85N / 25mm or less, and even more preferably 25N / 25mm or more and 73N / 25mm or less. The tensile strength in the CD direction when wet (WCDT) is preferably 3N / 25mm or more and 65N / 25mm or less, more preferably 4N / 25mm or more and 55N / 25mm or less, and even more preferably 9N / 25mm or more and 45N / 25mm or less. If the WMDT is less than 13N / 25mm or the WCDT is less than 3N / 25mm, the strength of the paper towel 1x is low, and it is easily torn during printing, and the function as the roll-shaped paper towel 1 is inferior. If the WMDT exceeds 100N / 25mm or the WCDT exceeds 65N / 25mm, paper dust will tend to accumulate on the printing plate, and the frequency of cleaning of the printing plate will increase.

[0037] Furthermore, the ratio (WMDT / WCDT) of the wet tensile strength in the MD (WMDT) to the wet tensile strength in the CD (WCDT) of the paper towel 1x is preferably 1.3 to 4.6, more preferably 1.5 to 4.1, and even more preferably 1.7 to 3.6. If the ratio exceeds 4.6, the WCDT will be low and the paper towel 1x will be prone to tearing or tearing during printing, resulting in poor functionality as a rolled paper towel 1.

[0038] Furthermore, the ratio ((WMDT / DMDT)×100(%)) of the tensile strength in the MD direction when wet to the tensile strength in the MD direction when dry of the paper towel 1x is preferably 50% or more and 95% or less, more preferably 65% ​​or more and 93% or less, and even more preferably 70% or more and 91% or less. Similarly, the ratio ((WCDT / DCDT)×100(%)) of the tensile strength in the CD direction when wet to the tensile strength in the CD direction when dry of the paper towel 1x is preferably 43% or more and 89% or less, more preferably 60% or more and 86% or less, and even more preferably 65% ​​or more and 83% or less. If the ratio ((WMDT / DMDT) x 100 (%)) is less than 50%, or if the ratio ((WCDT / DCDT) x 100 (%)) is less than 43%, the paper towel 1x will be prone to tearing when wet or when printed, resulting in poor functionality as a rolled paper towel 1.

[0039] (Elongation at break) The breaking elongation in the MD direction of the paper towel 1x is preferably 20% or more and 65% or less, more preferably 28% or more and 53% or less, and even more preferably 33% or more and 48% or less. The breaking elongation in the CD direction of the paper towel 1x is preferably 50% or more and 100% or less, more preferably 60% or more and 95% or less, and even more preferably 70% or more and 90% or less. By setting the breaking elongation in the MD direction or CD direction of the paper towel 1x within the above range, it becomes easier to control the pressure at which the paper towel 1x contacts the printing plate during printing, and it is possible to obtain a roll-shaped paper towel 1 that does not require frequent washing of the printing plate and can maintain the aesthetic quality of the print in a good condition. The breaking elongation in each direction of the paper towel 1x is measured based on JIS P 8113.

[0040] 3. Method for manufacturing paper towels and rolled paper towels As for the manufacturing method of paper towel 1x and rolled paper towel 1, when paper towel 1x is a kitchen towel containing synthetic fibers and pulp fibers, it can be manufactured, for example, in the following order: (1) laminating pulp fibers onto a specified spunbond nonwoven fabric and hydroentangling, (2) printing, (3) embossing, and (4) roll winding. At this time, in (1) hydroentanglement of the manufacturing method, pulp fibers are hydroentangled with synthetic fibers to obtain a nonwoven fabric containing synthetic fibers and pulp fibers. The hydroentanglement method is preferably performed by, for example, the method described in JP 2018-193634 A. In addition, in (2) printing of the manufacturing method, printing is performed on the surface by passing the base paper through a printing plate, and at this time, the printing speed is preferably 50 m / min to 600 m / min, more preferably 100 m / min to 450 m / min, and even more preferably 150 m / min to 300 m / min. By setting the printing speed within the above range, even if printing is performed on a paper towel 1x with a high basis weight as in the present application, paper powder is less likely to accumulate on the printing plate, and the aesthetic properties of the print can be improved. Furthermore, in (3) embossing treatment of the manufacturing method, it is preferable to perform a thermal embossing treatment using a matched steel (steel match) with a roll winder, and the embossing pattern is preferably a hexagonal shape.

[0041] Although the present invention has been described above using the embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope described in the above embodiments and examples. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. In addition, it is clear from the description of the claims that forms with such modifications or improvements can also be included in the technical scope of the present invention. EXAMPLES

[0042] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the examples shown below.

[0043] The rolled paper towels of Examples 1 to 19 and Comparative Examples 1 to 8 shown in Table 1 were produced through the steps of (1) hydroentanglement, (2) printing, (3) embossing, and (4) rolling. The above-mentioned parameters were measured for all the rolled paper towels of the Examples and Comparative Examples, and the following evaluations were performed. All the measurement results and evaluations are shown in Table 1.

[0044] Basis weight: The basis weight of the paper towel was actually measured and evaluated as follows. 40g / m 2 Less than: 1 point 40g / m 2 More than 50g / m 2 Less than: 2 points 50g / m 2 More than 60g / m 2 Less than: 3 points 60g / m 2 More than 100g / m 2 Less than: 4 points 100g / m 2 Above: 5 points

[0045] Cosmetic properties of printed area: The printed area of ​​the paper towel was observed and subjected to a sensory evaluation as follows. Particularly excellent: 5 points, excellent: 4 points, good: 3 points, poor: 2 points, particularly poor: 1 point The average value of 30 people was calculated and rounded off to one significant digit.

[0046] Frequency of cleaning of printing plate: The frequency of cleaning of printing plate in the printing process for paper towels was compared with the frequency of cleaning of printing plate in the printing process for toilet rolls, which are usually printed on the surface, and evaluated as follows. 150% or more: 1 point 130% or more but less than 150%: 2 points 120% to less than 130%: 3 points 110% to less than 120%: 4 points Less than 110%: 5 points

[0047] [Table 1]

[0048] As shown in Table 1, the rolled paper towels of Examples 1 to 19 all had sufficient basis weight, excellent decorativeness of the printed area, and required less frequent cleaning of the printing plate. On the other hand, the rolled paper towels of Comparative Examples 1 to 8 had insufficient basis weight, poor decorativeness of the printed area, or required more frequent cleaning of the printing plate. As described above, the rolled paper towel of the present invention is a rolled paper towel in which a single ply of high basis weight paper towel that has good functionality is wound into a roll, and which does not require frequent cleaning of the printing plate and can maintain the aesthetic quality of the print. A rolled paper towel and a method for producing the same can be provided. [Explanation of symbols]

[0049] 1 roll of paper towels 1a surface 1b back side 1e. The edge of the outermost roll of paper towels 1x Paper Towel 10 Printing 10a Line Segment 10b Both ends 10c A straight line connecting both ends 10d Parts separated by 3 mm or more in the flow direction 10e Parts other than 10d 200 test pieces 200a, 200d corner 210 Obi 220 Holder

Claims

1. A rolled paper towel having one ply of embossed paper towel having a patterned print on a surface thereof and wound into a roll, The paper towel has a basis weight of 50 g / m ２ More than 200g / m ２ is as follows: The water absorption of the paper towel per m 2 is 270 g or more and 600 g or less, The breaking elongation in the MD direction is 20% or more and 65% or less, The print is a line segment having a total length of 10 mm or more and a generally convex shape in the flow direction toward the end side of the paper towel, The rolled paper towel is characterized in that the line thickness of the generally convex portion at a distance of 3 mm or more from a straight line connecting both ends of the line segment in a direction parallel to the flow direction of the paper towel is 35% to 95% of the line thickness of the portion other than the portion at a distance of 3 mm or more.

2. The paper towel comprises synthetic fibers and pulp fibers; 2. The rolled paper towel according to claim 1, wherein the proportion of synthetic fibers in the paper towel is 5% or more and 45% or less, and the proportion of pulp fibers in the paper towel is 55% or more and 95% or less.

3. The synthetic fiber has a basis weight of 8 g / m ２ 55g / m or more ２ and the basis weight of the pulp fiber is 38 g / m ２ 160g / m or more ２ 3. The roll of paper towel according to claim 2, characterized in that:

4. The tensile strength in the CD direction (DCDT) of the paper towel when dry is 4 N / 25 mm or more and 80 N / 25 mm or less; The rolled paper towel according to any one of claims 1 to 3, characterized in that the ratio (DMDT / DCDT) of the tensile strength in the MD direction when dry (DMDT) to the tensile strength in the CD direction when dry (DCDT) of the paper towel is 1.2 or more and 4.5 or less.

5. 5. The rolled paper towel according to claim 1, wherein the tensile strength in the machine direction (DMDT) of the paper towel when dry is 15 N / 25 mm or more and 115 N / 25 mm or less.

6. The roll density of the rolled paper towel is 0.06 g / cm ３ 0.19g / cm or more ３ 6. The rolled paper towel of claim 1, wherein:

7. 7. The rolled paper towel according to claim 1, wherein the paper towel has a thickness of 0.45 mm or more and 1.8 mm or less.

8. 8. The roll-shaped paper towel according to claim 1, wherein the embossing depth is 0.07 mm or more and 2 mm or less.

9. 9. The roll of paper towel according to claim 1, wherein the paper towel is a kitchen towel.

10. 10. The method for producing a rolled paper towel according to claim 1, wherein the printing speed of the printing is 50 m / min or more and 600 m / min or less.

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