JP7798548B2 - kitchen towel roll - Google Patents

Description

The present invention relates to a kitchen towel roll.

In recent years, a variety of kitchen towels have been developed. Water and oil absorption capacity is important for kitchen towels, and papermaking techniques have been developed to increase these capacities. Technology has also been developed to reduce paper thickness by using embossed patterns.

For example, Patent Document 1 discloses an indentation and projection layer of an indentation and projection belt for indenting a wet fibrous web by pressing it in the press section of a tissue papermaking machine for producing high-bulk tissue paper, the indentation and projection layer being nonwoven and having a web-carrying side with a surface that cooperates with the fibrous web, the surface having depressions or elevated portions that form a three-dimensional structure on the surface; a press section and papermaking machine for producing high-bulk crepe tissue paper web; and a method for producing the same.
Patent Document 2 discloses kitchen paper made by laminating multiple sheets, the sheets constituting the front and back surfaces being crepe paper made from pulp, the sheet constituting the front surface being embossed and having a basis weight of 20 to 40 g/m ² , a sheet density of 0.01 g/cm ³ or more but less than 0.14 g/cm ³ , a dry tensile strength in the machine direction of 2500 cN or less, and a dry tensile strength in the cross direction of 700 cN or less, and the sheet constituting the back surface having a basis weight of 20 to 50 g/m ² and a sheet density of 0.14 g/cm ³ or more but less than 0.50 g/cm ³ . It also discloses that the sheets constituting the front and back surfaces of the kitchen paper are embossed, and the tops of the embossments on each sheet are bonded together (also known as pin-to-pin).
Furthermore, Patent Document 3 discloses a method for producing a rolled paper product, which includes the steps of preparing at least one paper web and embossing the at least one web with an embossing pattern that covers at least about 22% of the total surface area of the at least one web, wherein the pattern includes at least about 80% linear embossings, and the caliper of the finished product is smaller than the caliper of the embossed base sheet.

Special Publication No. 2011-506780 Patent No. 4714290 Special table 2016-540530 publication

However, when using the above technology to manufacture kitchen roll towels, the base paper itself is bulky and the embossing makes the roll loose, making it difficult to maintain the rolled shape during transportation or use, which can reduce the product's value. Generally, these problems can be addressed by applying tension during winding to adjust the roll looseness, but bulky paper has long interfiber distances, which reduces the web strength and leads to poor productivity due to paper breaks and other issues.

Another solution is to use paper strength enhancers to compensate for the lack of strength, but this has problems such as slowing down the water absorption rate and making the paper stiff and uneasy to use.In addition, adjusting the pulp composition and beating degree can increase strength and make the paper tighter, but this causes the embossing and base paper to collapse (stretch), reducing the bulk, and impairing the bulk and decorative properties.
As described above, it has been difficult to obtain a bulky embossed kitchen towel roll that is aesthetically pleasing, has a good feel when used, and has good shape retention when rolled.

The present invention was made in consideration of the above problems, and aims to provide a bulky kitchen towel roll that is aesthetically pleasing, has a pleasant feel when used, and retains its shape well.

The inventors of the present invention conducted extensive research to solve the above-mentioned problems. As a result, they discovered that the above-mentioned problems could be solved by applying a textured pattern different from an embossed pattern to a kitchen towel sheet wound into a kitchen towel roll having a specific volume within a specified range, and by adjusting the basis weight of the two plies of the kitchen towel sheet, the root mean square height of the surface roughness of specified portions, and the winding softness of the kitchen towel roll both inside and outside the roll, thereby completing the present invention. Specifically, the present invention provides the following:

(1) A first aspect of the present invention is a kitchen towel roll comprising a kitchen towel sheet having a specific volume of 7 ^cm3 /g to 22 ^cm3 /g, the kitchen towel sheet being formed by gluing together sheets having embossed patterns and laminating them into two plies, the kitchen towel sheet having a pattern of protrusions and recesses derived from the papermaking process and different from the embossed pattern, the two plies of the kitchen towel sheet having a basis weight of 30 g/ ^m2 to 54 g/ ^m2 , the root mean square height of the surface roughness in the portion not having the embossed pattern being 35 μm to 170 μm, the outer looseness of the kitchen towel roll (a position corresponding to 10% of the winding length from the outer edge of the outermost turn of the kitchen towel roll when the kitchen towel roll is unwound) being 5 mm to 15 mm, and the inner looseness of the kitchen towel roll (a position corresponding to 90% of the winding length from the outer edge of the outermost turn of the kitchen towel roll when the kitchen towel roll is unwound) being 2 mm to 10 mm.

(2) A second aspect of the present invention is the kitchen towel roll described in (1), characterized in that the embossing depth in the embossing pattern is 0.06 mm or more and 1.1 mm or less.

(3) A third aspect of the present invention is a kitchen towel roll according to (1) or (2), characterized in that the area ratio of the convex portions on the embossing roll for applying the embossing pattern is 4% or more and 40% or less.

(4) A fourth aspect of the present invention is a kitchen towel roll according to any one of (1) to (3), characterized in that the winding density of the kitchen towel roll is 0.22 m/ ^cm² or more and 0.68 m/ ^cm² or less.

(5) A fifth aspect of the present invention is a kitchen towel roll according to any one of (1) to (4), characterized in that the ratio of the embossing depth in the embossing pattern to the overall paper thickness of the kitchen towel sheet is 0.02 or more and 0.4 or less.

Accordingly, the present invention makes it possible to provide a bulky kitchen towel roll that is aesthetically pleasing, comfortable to use, and retains its shape well.

1 is a perspective view showing the appearance of a kitchen towel roll of the present invention. FIG. 1 is a diagram showing a method for measuring the winding softness of a kitchen towel roll of the present invention. FIG. 1 is a diagram showing an example of an embossing pattern in a kitchen towel roll of the present invention. FIG. 1 is a diagram showing a height profile on the XY plane as viewed through a microscope, using gray scales. FIG. 1 is a graph showing a height profile on the XY plane obtained by a microscope. FIG. 10 is a diagram showing how to determine the embossing depth for an embossing pattern. FIG. 10 is a diagram showing the height profile of a non-embossed portion on the XY plane as viewed under a microscope, using gray scales. FIG. 1 is a diagram showing a method for measuring the water absorption of a kitchen towel roll of the present invention.

Embodiments of the present invention are described in detail below. However, the following embodiments are presented for illustrative purposes, and the present invention is in no way limited to the embodiments described below.

<Kitchen towel roll>
Figure 1 is a perspective view showing the appearance of a kitchen towel roll 1 of the present invention. The kitchen towel roll 1 of the present invention is a kitchen towel sheet 1x formed by laminating two plies of embossed-pattern sheets with glue and winding them into a roll. It is preferable that the kitchen towel sheet 1x has perforations in the width direction at equal intervals in the machine direction (not shown).

1, the surface of kitchen towel sheet 1x facing the outside of the roll is referred to as surface 1a (surface of kitchen towel sheet 1x), and the surface facing the center of the roll is referred to as back surface 1b (back surface of kitchen towel sheet 1x). Furthermore, the outer edge of the outermost roll (end of winding) of kitchen towel sheet 1x is referred to as outer edge 1e.
In this case, the MD (Machine Direction) direction is the direction in which the kitchen towel sheet 1x is wound (the direction in which the kitchen towel sheet 1x is manufactured, also called the flow direction), and the CD (Cross Direction) direction is the direction perpendicular to the MD direction (also called the width direction).

(Roll length and diameter)
The roll length of the kitchen towel roll 1 is preferably 14 m or more and 44 m or less. The roll diameter DR of the kitchen towel roll 1 is preferably 110 mm or more and 189 mm or less. A roll length of less than 14 m results in poor retention of the roll shape, while a roll length of more than 44 m results in high roll density and low bulk. A roll diameter DR of less than 110 mm results in high roll density and low bulk, while a roll diameter DR of more than 189 mm results in poor retention of the roll shape and a low roll density, resulting in a poor usability despite the bulk.

The winding length is more preferably 21 m or more and 37 m or less, and even more preferably 25 m or more and 33 m or less. The winding diameter DR is more preferably 130 mm or more and 176 mm or less, and even more preferably 140 mm or more and 163 mm or less.
The roll length is determined by first measuring the length of 10 sheets of kitchen towel sheets 1x between the perforations of the kitchen towel roll 1. Then, the number of sheets in the kitchen towel roll 1 is measured, and the roll length is calculated 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 the number of sheets is 150, the roll length is 1.80 m x (150/10) = 27 m. If the kitchen towel roll 1 does not have perforations, the roll length can be measured by actual measurement. The roll diameter DR is measured using a diameter ruler manufactured by Muratec KDS Corporation. Ten kitchen towel rolls 1 are measured, and the measurement results are averaged.
The length between perforations (the length of the sheet in the machine direction) is preferably 100 mm to 270 mm, more preferably 125 mm to 240 mm, and even more preferably 150 mm to 210 mm. By keeping the length within this range, when using a bulky kitchen towel roll 1 such as the present application, the area used can be appropriate, resulting in a good usability.

(Roll width and roll mass)
The roll width of the kitchen towel roll 1 is preferably 150 mm to 380 mm, more preferably 200 mm to 340 mm, and even more preferably 250 mm to 300 mm. By keeping the width within this range, when using a bulky kitchen towel roll 1 such as that of the present application, the area used can be appropriate, resulting in a good usability.
The roll mass of the kitchen towel roll 1 is preferably 160 g to 550 g, more preferably 230 g to 450 g, and even more preferably 270 g to 380 g. By keeping the mass within this range, when using a bulky kitchen towel roll 1 such as that of the present application, it is possible to achieve a good usability without being bulky.
The roll mass is the mass per 280 mm of roll width excluding the core (paper tube). If the roll width is not 280 mm, it is converted to the mass per 280 mm by proportional calculation.

(Roll density and winding density)
The roll density of the kitchen towel roll 1 is preferably 0.04 g/ ^cm3 or more and 0.15 g/ ^cm3 or less, and the winding density is preferably 0.22 m/ ^cm2 or more and 0.68 m/ ^cm2 or less. If the roll density of the kitchen towel roll 1 is less than 0.04 g/ ^cm3 or the winding density is less than 0.22 m/ ^cm2 , the rolled shape of the kitchen towel roll 1 cannot be maintained. If the roll density of the kitchen towel roll 1 exceeds 0.15 g/ ^cm3 or the winding density exceeds 0.68 m/ ^cm2 , the bulk of the kitchen towel roll 1 will be low and the water absorption will be poor.
The roll density of the kitchen towel roll 1 is preferably 0.05 g/ ^cm3 or more and 0.13 g/ ^cm3 or less, and more preferably 0.06 g/ ^cm3 or more and 0.09 g/ ^cm3 or less. The winding density of the kitchen towel roll 1 is more preferably 0.25 m/ ^cm2 or more and 0.54 m/ ^cm2 or less, and even more preferably 0.28 m/ ^cm2 or more and 0.40 m/ ^cm2 or less.

The winding density is expressed as (winding length × number of plies) ÷ (cross-sectional area of the roll). The cross-sectional area of the roll is expressed as {cross-sectional area of the outer diameter part of the roll (winding diameter DR) - (cross-sectional area of the outer diameter part of the core (cardboard tube))}. The core outer diameter DI is the diameter of the center hole of the roll.
For example, if the winding length is 27 m, there are 2 plies, the winding diameter DR is 150 mm, and the core outer diameter DI is 39 mm, then the winding density = (27 m × 2) ÷ {3.14 × (150 mm ÷ 2 ÷ 10) ² - 3.14 × (39 mm ÷ 2 ÷ 10) ² } = 0.33 m/cm ^2. If kitchen towel roll 1 does not have a core, the diameter of the center hole is taken as the core outer diameter DI.
The roll density is expressed as (roll mass) ÷ (roll volume). The roll mass is the mass of the kitchen towel roll 1 per 280 mm of roll width. The 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)] × roll width (converted per 280 mm). For example, if the roll mass (excluding the core) per 280 mm of roll width is 382 g, the winding diameter is 150 mm, and the core's outer diameter is 39 mm, the roll density = 382 g ÷ [{3.14 × (150 mm ÷ 2 ÷ 10) ² - 3.14 × (39 mm ÷ 2 ÷ 10) ² } × (280 mm ÷ 10)] = 0.083 g/cm ^3. If the kitchen towel roll 1 does not have a core, the diameter of the central hole is taken as the core outer diameter DI.

(Core outer diameter)
Furthermore, the core outer diameter DI of the kitchen towel roll 1 of the present invention, which is the outer diameter of the core, is preferably 25 mm to 55 mm, more preferably 30 mm to 50 mm, and even more preferably 35 mm to 45 mm. Having the core outer diameter DI within the above range makes it easier to optimize the winding softness both inside and outside the roll. Furthermore, because the kitchen towel roll 1 maintains its wound shape without being bulky, the kitchen towel roll 1 can be easily stored in a kitchen towel holder, and the kitchen towel roll 1 is also easy to handle during production.
The core outer diameter is measured using a diameter ruler manufactured by Muratec KDS Co., Ltd. Ten kitchen towel rolls 1 are measured, and the measurement results are averaged.
Furthermore, the mass of the core (paper tube) per 280 mm roll width is preferably 5 g or more and 22 g or less, more preferably 7 g or more and 17 g or less, and even more preferably 9 g or more and 13 g or less.

(Rolling softness)
Furthermore, the outer winding softness of the kitchen towel roll 1 is 5 mm to 15 mm, and the inner winding softness is 2 mm to 10 mm. If the outer winding softness is less than 5 mm or the inner winding softness is less than 2 mm, the kitchen towel sheet 1x will be crushed when in a rolled state, resulting in low water absorbency. If the outer winding softness exceeds 15 mm or the inner winding softness exceeds 10 mm, the winding will be too soft and the rolled shape will not be maintained.
In this case, "outside of the roll" refers to a position that corresponds to 10% of the roll length from the outer edge 1e of the outermost turn of kitchen towel roll 1 when kitchen towel roll 1 is unwound, and "inside of the roll" similarly refers to a position that corresponds to 90% of the roll length from the outer edge 1e of the outermost turn of kitchen towel roll 1 when kitchen towel roll 1 is unwound. The outer looseness of kitchen towel roll 1 is preferably 6 mm to 13 mm, and more preferably 7 mm to 11 mm. The inner looseness of kitchen towel roll 1 is preferably 3 mm to 9 mm, and more preferably 4 mm to 8 mm.
The rolling softness is measured by the following method.

The winding looseness can be defined as the amount of deformation of the kitchen towel roll 1 when a load of 625 g is applied to the kitchen towel roll 1. More specifically, the winding looseness is measured using a measuring device 40 shown in FIG. 2. The measuring device 40 includes a base 41, support rods 42a and 42b, a movable weight support plate 43, and a 625 g weight 44. The two support rods 42a and 42b rise vertically from the base 41, and insertion holes for the support rods 42a and 42b are provided at both ends of the rectangular movable weight support plate 43. The kitchen towel roll 1 is placed on the base 41 between the support rods 42a and 42b, and the support rods 42a and 42b are inserted into the movable weight support plate 43 from above the kitchen towel roll 1, and the movable weight support plate 43 is placed on the top of the kitchen towel roll 1. The height of the movable weight support plate 43 in this state is defined as the initial height _h1 . Furthermore, when weight 44 is placed on movable weight placing plate 43, the weight of weight 44 causes movable weight placing plate 43 to slide through support rods 42a and 42b, deforming and sinking kitchen towel roll 1. The height _h2 at this time is measured, and ( _h2 - _h1 ) is calculated as the amount of deformation in the diameter of kitchen towel roll 1. Next, kitchen towel roll 1 is rotated 120 degrees, and the same procedure is used to calculate the winding looseness. It is rotated another 120 degrees, and the same procedure is repeated. The average of three measurements is used as the measurement value.

<Kitchen towel sheet>
(Basic weight)
The basis weight of the two plies of the kitchen towel sheet 1x is 30 g/ ^m2 or more and 54 g/ ^m2 or less. If the basis weight of the two plies is less than 30 g/ ^m2 , the water absorption capacity of the kitchen towel sheet 1x will be poor. If the basis weight exceeds 54 g/ ^m2 , the kitchen towel sheet 1x will become stiff and difficult to wipe. The basis weight of the two plies of the kitchen towel sheet 1x is preferably 34 g/ ^m2 or more and 50 g/ ^m2 or less, and more preferably 38 g/ ^m2 or more and 46 g/ ^m2 or less. The basis weight is measured in accordance with JIS P 8124.

The basis weight per ply of the kitchen towel sheet 1x is preferably 14 g/m2 or more and 28 g/ ^m2 or less, more preferably 16 g/ ^m2 or more and 26 g/ ^m2 or less, and even more preferably 18 g/ ^m2 or ^more and 24 g/m2 or less, for both the front surface 1a and the back surface ^1b . The basis weight per ply is determined by measuring the basis weight of two plies, peeling the plies, measuring the mass of the front surface 1a and the back surface 1b, and calculating the basis weight of the front surface 1a and the back surface 1b from the mass ratio.
Furthermore, in the kitchen towel sheet 1x, the basis weight of the back surface 1b is preferably 0.1 g/ ^m² to 1 g/ ^m² higher than the basis weight of the front surface 1a. Because the front surface 1a has an embossed pattern (described below), it tends to have a lower water absorption capacity than the back surface 1b. By increasing the basis weight of the back surface 1b, the water absorption capacity of the back surface 1b can be increased, thereby increasing the overall water absorption capacity. It is more preferable that the basis weight of the back surface 1b be 0.1 g/ ^m² to 0.8 g/ ^m² higher than the basis weight of the front surface 1a, and even more preferably 0.2 g/ ^m² to 0.5 g/ ^m² higher.

(paper thickness)
The paper thickness of the kitchen towel sheet 1x is 1.3 mm/10 sheets or more and 5 mm/10 sheets or less. If the paper thickness is less than 1.3 mm/10 sheets, the kitchen towel sheet 1x will have a poor feel when used, and if it exceeds 5 mm/10 sheets, the feel will be poor despite its bulk. The paper thickness of the kitchen towel sheet 1x is preferably 2.0 mm/10 sheets or more and 4.4 mm/10 sheets or less, and more preferably 2.6 mm/10 sheets or more and 3.8 mm/10 sheets or less.
The paper thickness is measured using a thickness gauge (a dial thickness gauge "PEACOCK" manufactured by Ozaki Seisakusho 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 is read when the probe is lowered at a speed of 1 mm per second or less. Five sets of 1x kitchen towel sheets, each laminated in two plies, are stacked to measure 10 sheets. The measurement is also repeated 10 times at different locations, and the measurement results are averaged.

(embossed pattern)
The kitchen towel roll 1 (kitchen towel sheet 1x) of the present invention is embossed and has an embossed pattern. Furthermore, the kitchen towel sheet 1x of the present invention is formed by laminating two plies after embossing the sheet. When laminating the two plies, a ply bond glue is applied and bonded. By bonding the plies together in this way, the plies are strongly bonded together, and the kitchen towel sheet 1x is less likely to tear or peel off even when wet.

The ply on the surface 1a of the kitchen towel sheet 1x has an embossed pattern. By applying an embossed pattern to the surface 1a, glue can be applied to the embossed portions of the embossed pattern for adhesion, which reduces ply peeling in the kitchen towel sheet 1x and allows for a consistent water absorption rate. The embossed pattern is not particularly limited as long as it is a pattern commonly used on kitchen towels, such as a dotted or linear pattern. A linear embossed pattern is preferred. Specifically, the linear embossed pattern may be, as shown in FIG. 3, a pattern that includes two types of figures: a roughly circular figure with another pattern inside, and a figure that is roughly line-symmetrical vertically and horizontally as a whole and includes a combination of multiple curves and figures. For the roughly circular figure, it is preferable that the roughly circular figure be double.
Furthermore, the dimensions of the embossed pattern are such that the rectangle E (E is not the embossed pattern) surrounding the embossed pattern is preferably a square with sides of 2 cm to 25 cm, more preferably a square with sides of 5 cm to 20 cm, and even more preferably a square with sides of 8 cm to 15 cm. The lengthwise direction of this rectangle E is preferably parallel to the flow direction of the kitchen towel roll 1, and the widthwise direction is preferably parallel to the width direction of the kitchen towel roll 1, although they may be tilted. The use of such a pattern can improve the feel of use in a bulky kitchen towel sheet 1x as described herein, provide excellent aesthetic appeal, and make it easier for the kitchen towel roll 1 to maintain its rolled shape.

In this case, for embossments in the linear embossing pattern that are 0.1 mm or more and 4 mm or less in thickness and 5 mm or more in length, the total length when the lengths of the embossments are added together is preferably 50 cm/100 ^cm2 or more and 550 cm/100 ^cm2 or less, more preferably 80 cm/100 ^cm2 or more and 410 cm/100 ^cm2 or less, and even more preferably 110 cm/100 ^cm2 or more and 300 cm/100 ^cm2 or less.
The total length is measured as the sum of the embossment lengths of all embossments with a thickness of 0.1 mm to 4 mm and a length of 5 mm or more within a rectangle E that includes all of the embossed patterns, as shown in Figure 3, and is taken as the total length per 100 ^cm2 . The size of one side of this rectangle E can be changed as appropriate depending on the size of the embossed pattern. If the rectangle that includes all of the embossed patterns includes an embossed pattern adjacent to an embossed pattern included within the rectangle, the length of that adjacent embossed pattern is also measured and included in the total length. If the size of one side of rectangle E cannot be clearly determined based on the embossed pattern, the size of rectangle E is set to 10 x 10 cm, and the total length of the embossments included in this rectangle E is measured. By keeping the total length within the above range, the bulky kitchen towel sheet 1x of the present application can be made to have a good feel in use and also have a good aesthetic appearance. The total length is determined by actual measurement using the method described above, but it may also be measured using a conventional microscope.

In the embossing pattern, the embossing depth is preferably 0.06 mm or more and 1.1 mm or less. If the embossing depth is less than 0.06 mm, the aesthetic appeal of the kitchen towel roll 1 is poor. If the depth exceeds 1.1 mm, the kitchen towel roll 1 becomes loose and the rolled shape cannot be maintained.
The depth of the embossing in the embossing pattern is more preferably 0.10 mm or more and 0.80 mm or less, and further preferably 0.20 mm or more and 0.55 mm or less.

The depth of the embossment is measured using a microscope. A microscope such as the KEYENCE One-Shot 3D Measuring Microscope VR-3100 can be used. Software such as the VR-H1A can be used to observe, measure, and analyze microscope images. Measurement conditions are a magnification of 25x and a field of view of 12mm x 9mm. The measurement magnification and field of view can be changed as needed depending on the desired size of the embossment.

FIG. 4 shows a height profile on the X-Y plane taken with a microscope, with the height of the surface of the kitchen towel sheet 1x represented by shading. The linear areas in FIG. 4 that 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 kitchen towel sheet 1x. Furthermore, during measurement, three wraps of the kitchen towel sheet 1x are removed from the kitchen towel roll 1, and the fourth wrap of the kitchen towel sheet 1x is used to perform the measurement on the two-ply sheet. Furthermore, if there are perforations, these are avoided during the measurement.
First, a line segment AB is drawn as shown in Figure 4 to obtain the height profile shown in Figure 5. The line segment AB can be drawn across the embossments. The line segment AB is drawn in the width direction (CD) of the kitchen towel sheet 1x. However, if the spacing between embossments is narrow, e.g., 2 mm or less, resulting in a low height of the convex portions described below, the line segment may be drawn diagonally or in the machine direction. The height profile is a (measured) cross-sectional curve S representing the unevenness of the actual sample surface of the kitchen towel sheet 1x. However, it also contains noise (steep peaks due to fiber clumps, whisker-like fibers, or fiber-free areas on the surface of the kitchen towel sheet 1x). Therefore, when calculating the height difference of the unevenness, it is necessary to remove such noise peaks.

Therefore, the (measured) cross-sectional curve S in Figure 5 was smoothed using the filter size of the weighted average radio button, ±12, to obtain the cross-sectional curve W in Figure 6. Note that smoothing using the filter of the weighted average radio button can be automatically obtained using the above-mentioned analysis software. Then, in the graph shown in Figure 6, the average of the maximum values on the vertical axis of the convex portion H1 and the convex portion H2 adjacent to the convex portion H1 was calculated, and the minimum value on the vertical axis of the concave portion D1 sandwiched between the convex portions H1 and H2 was determined. The value obtained by subtracting the minimum value from the average of the maximum values thus obtained was used as the provisional emboss depth. Then, as shown in Figure 6, similar measurements were performed at two consecutive locations on the cross-sectional curve (the concave portion D1 and the concave portion D2 sandwiched between the convex portions H3 and H4) (two consecutive locations in total, resulting in two measurement results at this point). The kitchen towel roll 1 is then rotated three times by 90 degrees in the direction of the flow of the kitchen towel sheet 1x, and the same measurements as above are taken at each position (for a total of four measurement positions in the flow direction), and the average value of the total eight positions (2 x 4) is ultimately used as the embossing depth.
Since the kitchen towel sheet 1x of the present invention has a pattern of protrusions and recesses derived from the papermaking process, which is different from the embossed pattern, there is variation in the height of the left and right convex portions sandwiching the concave portion. Therefore, if the difference in the vertical axis between the convex portions sandwiching the concave portion (for example, convex portions H3 and H4 sandwiching concave portion D2) is 0.2 mm or more, measurements are performed at a location that avoids that portion.

Furthermore, the ratio of the embossing depth in the embossing pattern to the overall paper thickness of the kitchen towel sheet 1x, i.e., the ratio of the embossing depth in the embossing pattern to the overall paper thickness of the kitchen towel sheet 1x, is preferably 0.02 or more and 0.4 or less. If the ratio is less than 0.02, the aesthetic appeal of the kitchen towel roll 1 will be poor. If the ratio exceeds 0.4, the kitchen towel roll 1 will become loosely wound and will not be able to maintain its rolled shape. It is more preferable that the ratio of the embossing depth in the embossing pattern to the overall paper thickness of the kitchen towel sheet 1x be 0.04 or more and 0.35 or less, and even more preferably 0.08 or more and 0.20 or less.

There are no particular restrictions on whether the ply on the back surface 1b of the kitchen towel sheet 1x has an embossed pattern, as long as it has a different, uneven pattern resulting from the papermaking process than the embossed pattern. It may have nested embossing or pin-to-pin embossing, or it may not have embossing; however, nested embossing or no embossing is preferred, and no embossing is more preferred. Conventional kitchen towels ensure water absorption using pin-to-pin or nested patterns, but when using thick base paper as in the present application, as mentioned above, embossing can cause the paper to collapse, resulting in poor aesthetic appeal. For this reason, it is preferable that the front surface 1a have linear embossing and the back surface 1b have no embossing.

In this case, the root mean square height Sq of the surface roughness of the kitchen towel sheet 1x in the portion without the embossed pattern (hereinafter also referred to as the non-embossed portion) is 35 μm to 170 μm, preferably 50 μm to 150 μm, and more preferably 60 μm to 100 μm. If the root mean square height Sq of the surface roughness is less than 35 μm, the kitchen towel sheets 1x will slip against each other when wound up, making it impossible to maintain the rolled shape. If Sq exceeds 170 μm, the kitchen towel roll 1 will become loose and will not be able to maintain the rolled shape.
The root mean square height Sq of the surface roughness of the non-embossed portion is measured using a microscope. As with the embossing depth described above, a microscope with the product name "One-Shot 3D Measuring Microscope VR-3100" manufactured by KEYENCE Corporation can be used. Software with the product name "VR-H1A" can be used for observing, measuring, and analyzing microscope images. Measurement conditions are a magnification of 38x and a field of view area of 8mm x 6mm. The measurement magnification and field of view area may be changed as appropriate depending on the desired size of the embossing.

For the image obtained as shown in Figure 7, filters are set in the same way as for the embossing depth described above. Specifically, an S-filter (low-pass filter) is set to remove components on a scale smaller than the cutoff wavelength, and an L-filter (high-pass filter) is set to remove components on a scale larger than the cutoff wavelength from the image. Here, the S-filter is set to 500 μm, and the L-filter is set to 8 mm. By selecting the S-filter and L-filter, the root-mean-square height Sq is automatically calculated.
As with the embossing depth, the non-embossed portion is measured by removing three laps of kitchen towel sheet 1x from kitchen towel roll 1 and using the fourth lap of kitchen towel sheet 1x to measure the two-ply sheet. Any perforations are also avoided during the measurement. Measurements are taken at two locations across the width of the kitchen towel roll, and then the kitchen towel roll 1 is rotated three times by 90 degrees in the machine direction of kitchen towel sheet 1x, and the same measurements are taken at each location (for a total of four measurement locations in the machine direction). The average of these eight locations (2 x 4) is ultimately used as the root-mean-square height Sq.

(Water absorption amount)
In the present invention, the water absorption per ^m2 (per unit weight) of the two plies of the kitchen towel sheet 1x is preferably 220 g or more and 600 g or less. If the water absorption per ^m2 is less than 220 g, the kitchen towel sheet 1x will have a poor feel when used, and if it exceeds 600 g, the kitchen towel sheet 1x will have a thicker paper and will have a poorer aesthetic appearance. The water absorption per ^m2 is more preferably 270 g or more and 550 g or less, and even more preferably 370 g or more and 480 g or less.
Furthermore, the water absorption per gram (per unit weight) of the two plies of the kitchen towel sheet 1x is preferably 6 g or more. If the water absorption per gram is less than 6 g, the kitchen towel sheet 1x will have a poor feel when used. The water absorption per gram is more preferably 7 g or more and 14 g or less, and even more preferably 8 g or more and 12 g or less.

Furthermore, the water absorption per ^m2 between the two plies of the kitchen towel sheet 1x is preferably 100 g or more and 300 g or less. If the water absorption per ^m2 between the two plies is less than 100 g, the kitchen towel sheet 1x will have a poor feel when used, and if it exceeds 300 g, the kitchen towel sheet 1x will be thick and bulky, resulting in poor aesthetic appeal. In this case, the water absorption per ^m2 between the two plies is the value obtained by subtracting the water absorption per ^m2 of one ply (front surface 1a) and the water absorption per ^m2 of one ply (back surface 1b), described below, from the water absorption per ^m2 of the two plies.
The water absorption per square ^meter between the two plies is more preferably 130 g or more and 280 g or less, and even more preferably 160 g or more and 260 g or less. The water absorption of each kitchen towel sheet 1x is measured as follows.

Figure 8 shows a method for measuring the water absorption of the kitchen towel roll 1 of the present invention. First, a two-ply kitchen towel sheet 1x is taken and cut using a square template with each piece measuring 7.6 cm (3 inches) to prepare a rectangular test piece 200 with each side measuring 7.6 cm. The mass of the test piece 200 before water absorption is measured using an electronic balance. The test piece 200 is set in a holder 220 (a jig that fixes three points of the test piece 200, made of a metal that does not absorb moisture).
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 and holder 220 are removed from the distilled water, and as shown in FIG. 8, a band 210 is attached to one corner 200d of the test piece 200. The band 210 is made by cutting the same kitchen towel sheet 1x as the sample to be measured into a size of 2 mm wide x 15 mm long, peeling off the ply, and using the backside ply, attaching it to a portion of the test piece 200 6 mm from the corner 200d toward the center. Next, the holder 220 and test piece 200 are hung from a rod placed in an empty water tank with the corner 200a opposite the corner 200d facing up, and the tank lid is closed and left for 10 minutes. Thereafter, the holder 220 and test piece 200 are removed from the water tank, the band 210 and holder 220 are removed, and the mass of the test piece 200 is measured using an electronic balance. From the change in mass of the test piece 200 before and after immersion in distilled water, the amount of distilled water absorbed per 1 ^m2 of the test piece 200 (g water/ ^m2 of sheet) is calculated. Furthermore, by dividing the amount of water absorbed per 1 ^m2 (g water/ ^m2 of sheet) by the basis weight of two plies of the test piece 200, the amount of water absorbed per 1 ^m2 (g water/ ^m2 of sheet)/basis weight (g sheet/ ^m2 of sheet) = amount of water absorbed per 1 g (g water/g of sheet). Measurements are performed five times for each sample, and the average value is used.
The water absorption of one ply was measured by cutting a kitchen towel sheet 1x, which was stacked on two plies, using a square template with each side measuring 7.6 cm (3 inches) to obtain a rectangular test piece 200 with each side measuring 7.6 cm, and then peeling the plies off to obtain the test piece 200 for measuring the water absorption of one ply. The measurement method was the same as for two plies.
The measurement is carried out in accordance with 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.

In the present invention, the water absorption per ^m2 of one ply (front surface 1a) of kitchen towel sheet 1x is preferably 50 g to 160 g, more preferably 60 g to 145 g, and even more preferably 70 g to 130 g. On the other hand, the water absorption per ^m2 of one ply (back surface 1b) of kitchen towel sheet 1x is preferably 50 g to 165 g, more preferably 60 g to 150 g, and even more preferably 70 g to 135 g.
The water absorption per gram of one ply (front surface 1a) of the kitchen towel sheet 1x is preferably 3.0 g or more, more preferably 3.5 g to 7.0 g or less, and even more preferably 4.0 g to 6.0 g or less. On the other hand, the water absorption per gram of one ply (back surface 1b) of the kitchen towel sheet 1x is preferably 3.1 g or more, more preferably 3.6 g to 7.1 g or less, and even more preferably 4.1 g to 6.1 g or less.

(specific volume)
The specific volume of the kitchen towel sheet 1x is 7 cm ³ /g or more and 22 cm ³ /g or less. If the specific volume of the kitchen towel sheet 1x is less than 7 cm ³ /g, the required bulkiness of the kitchen towel sheet 1x cannot be achieved, and if it exceeds 22 cm ³ /g, the feel in use is poor despite the bulk. The specific volume is preferably 9 cm ³ /g or more and 20 cm ³ /g or less, and more preferably 12 cm ³ /g or more and 17 cm ³ /g or less. The specific volume is expressed as the volume in cm ³ per unit g, obtained by dividing the paper thickness per two plies of the kitchen towel sheet 1x by the basis weight per two plies.

(DMDT and DCDT)
The two plies of the kitchen towel sheet 1x preferably have a dry machine direction tensile strength (DMDT) of 4.5 N/25 mm or more and 21 N/25 mm or less, and a dry cross direction tensile strength (DCDT) of 4.5 N/25 mm or more and 21 N/25 mm or less, based on JIS P 8113. If the DMDT or DCDT is less than 4.5 N/25 mm, the kitchen towel sheet 1x will be prone to tearing upon water absorption, resulting in a poor feel in use. If the DMDT or DCDT is greater than 21 N/25 mm, the density of the kitchen towel sheet 1x will be high, making it stiff and resulting in a poor feel in use.
The DMDT is more preferably 6.0 N/25 mm or more and 17 N/25 mm or less, and even more preferably 7.5 N/25 mm or more and 12 N/25 mm or less. The DCDT is more preferably 6.0 N/25 mm or more and 17 N/25 mm or less, and even more preferably 7.5 N/25 mm or more and 12 N/25 mm or less.
The ratio of DMDT to DCDT (DMDT/DCDT) is preferably 0.9 or more and 1.6 or less, more preferably 1.0 or more and 1.4 or less, and even more preferably 1.0 or more and 1.2 or less.

(WMDT and WCDT)
Furthermore, the two plies of the kitchen towel sheet 1x preferably have a wet machine direction tensile strength (WMDT) of 1.5 N/25 mm or more and 8.0 N/25 mm or less, both based on the former JIS S 3104, and a wet cross direction tensile strength (WCDT) of 1.5 N/25 mm or more and 8.0 N/25 mm or less. If the WMDT or WCDT is less than 1.5 N/25 mm, in a kitchen towel sheet 1x with high water absorption as in the present application, the kitchen towel sheet 1x will be prone to tearing when absorbing water, resulting in an inferior feel in use, and if the WMDT or WCDT exceeds 8.0 N/25 mm, the density of the kitchen towel sheet 1x will be high, making it stiff and resulting in an inferior feel in use.
The WMDT is more preferably 2.0 N/25 mm or more and 6.0 N/25 mm or less, and even more preferably 2.5 N/25 mm or more and 4.5 N/25 mm or less. The WCDT is more preferably 2.0 N/25 mm or more and 6.0 N/25 mm or less, and even more preferably 2.5 N/25 mm or more and 4.5 N/25 mm or less.
The ratio of WMDT to WCDT (WMDT/WCDT) is preferably 0.9 or more and 1.6 or less, more preferably 1.0 or more and 1.4 or less, and even more preferably 1.0 or more and 1.2 or less.

(Ply Peel Strength)
The ply peel strength of the kitchen towel sheet 1x is preferably 0.04 N/75 mm or more and 2.1 N/75 mm or less. If the ply peel strength is less than 0.04 N/75 mm, the plies will peel off from each other, resulting in a poor usability, while if the ply peel strength exceeds 2.1 N/75 mm, the kitchen towel sheet 1x will be stiff and result in a poor usability.
The ply peel strength of the kitchen towel sheet 1x is more preferably 0.10 N/75 mm or more and 1.2 N/75 mm or less, and even more preferably 0.15 N/75 mm or more and 0.6 N/75 mm or less.
The ply peel strength can be measured using a tensile tester (STB-1225S, manufactured by A&D Co., Ltd.) in accordance with the tensile test method of JIS P 8113, under the standard conditions specified in JIS P 8111. First, a test piece measuring 75 mm in the width direction and 200 mm in the machine direction is taken from the kitchen towel roll sample 1. Next, the ply is peeled 35 mm in the machine direction. One side of the peeled ply is clamped and fixed 15 mm in the machine direction between upper grippers (75 mm wide). The other ply is also clamped and fixed 15 mm in the machine direction between lower grippers (75 mm wide). The pitch (spacing) of the grippers is 20 mm. Next, the sample is pulled (peel) at a pulling speed of 100 mm/min, and strength data is collected. Data is obtained every 20 μm, and the data from 40 mm to 150 mm (measurement length 110 mm) after the start of measurement is averaged to determine the peel strength (N/75 mm). However, if the perforation is included in the distance from 40 mm to 150 mm after the start of measurement, the distance after the start of measurement can be shortened from 40 mm to, for example, 90 mm (measurement length 50 mm) as long as it does not include the perforation.

(Method for manufacturing kitchen towel sheets and kitchen towel rolls)
The kitchen towel sheet 1x and the kitchen towel roll 1 can be manufactured, for example, in the following order: (1) papermaking and creping, (2) embossing, and (3) roll winding. The manufacturing process preferably uses through-air dryer technology. In this case, a textured pattern derived from the papermaking process (fabric), different from the embossing pattern described above, is applied to the kitchen towel sheet 1x during the papermaking process. This textured pattern increases the water absorption capacity of the kitchen towel sheet 1x. "Derived from the papermaking process" means that the textured pattern is applied between the headbox of the papermaking machine and the entrance of the Yankee dryer during the papermaking process of the kitchen towel sheet 1x. The textured pattern is formed by drying the sheet together with the fabric in the through-air dryer section.
The unevenness pattern can be changed as needed by changing the fabric pattern (fine pattern, coarse pattern). Changing the unevenness pattern changes the specific volume (paper thickness), but it is preferable to select a pattern that ensures that the specific volume (paper thickness) of the base paper falls within the numerical range described below. It is also preferable to select a pattern that ensures that the root mean square height Sq of the surface roughness of the non-embossed portion of the kitchen towel sheet 1x falls within the numerical range described above.

When using base paper made using this through-air dryer, the area ratio of the convex portions on the embossing roll for applying the embossing pattern is preferably 4% to 40%. If the area ratio is less than 4%, the decorative properties of the kitchen towel sheet 1x and the kitchen towel roll 1 will be poor. If the area ratio is more than 40%, the bulk will be low and the water absorption will be poor.
The area ratio of the convex portions is preferably 6% to 30%, and more preferably 9% to 18%. The shapes of the convex portions and embossments alone can be any shape, including circular, elliptical, rectangular, square, floral, logo, and lettering, but linear embossing is preferred, as described above. As described above, the embossing is preferably provided only on the surface 1a of the kitchen towel sheet 1x.

In this case, the basis weight of two plies of base paper used to manufacture the kitchen towel sheet 1x (twice the basis weight of one ply) is preferably 31 g/ ^m² to 58 g/ ^m² , more preferably 35 g/ ^m² to 54 g/ ^m² , and even more preferably 39 g/ ^m² to 50 g/ ^m² . Furthermore, the paper thickness is preferably 1.4 mm/10 sheets to 5.4 mm/10 sheets, more preferably 2.1 mm/10 sheets to 4.8 mm/10 sheets, and even more preferably 2.7 mm/10 sheets to 4.2 mm/10 sheets. Furthermore, the specific volume is preferably 7 ^cm³ /g to 22 ^cm³ /g, more preferably 9 ^cm³ /g to 20 ^cm³ /g, and even more preferably 12 ^cm³ /g to 17 ^cm³ /g.

The ratio of the embossing depth in the embossing pattern to the thickness of the base paper of the kitchen towel sheet 1x (i.e., the ratio of the embossing depth in the embossing pattern to the thickness of the base paper of the kitchen towel sheet 1x) is preferably 0.01 to 0.38, more preferably 0.03 to 0.33, and even more preferably 0.07 to 0.18. By keeping it within this range, in the case of a bulky kitchen towel sheet 1x such as that of the present application, it is possible to improve the feel of use and also improve the aesthetic appeal.
Furthermore, in order to improve the feel and aesthetic appeal of the kitchen towel sheet 1x, the difference between the specific volume of the kitchen towel sheet 1x and the specific volume of the base paper (difference between the specific volume of the kitchen towel sheet 1x and the specific volume of the base paper) is preferably from -3 cm ³ /g to 2 cm ³ /g, more preferably from -2 cm ³ /g to 1 cm ³ /g, even more preferably from -1 cm ³ /g to 0.5 cm ³ /g, and particularly preferably from -0.5 cm ³ /g to 0 cm ³ /g.

It goes without saying that the present invention is not limited to the above-described embodiments, and encompasses various modifications and equivalents that fall within the spirit and scope of the present invention.

Through the steps of (1) papermaking and creping, (2) embossing, and (3) rolling, kitchen towel sheets and kitchen towel rolls of Examples 1 to 21 and Comparative Examples 1 to 10 were manufactured. The kitchen towel rolls of all of the above Examples and Comparative Examples were measured and evaluated for the above-mentioned parameters.
The number and thickness of the embossing patterns were changed as appropriate for each example and comparative example, and all embossing was performed only on the front side of the kitchen towel sheet. For rolls with widths other than 280 mm, the roll mass was calculated per 280 mm width and reported.

The manufactured kitchen towel sheets and kitchen towel rolls were evaluated for the following items.

(Maintaining the roll shape)
Ten kitchen towel rolls were dropped from a height of 75 cm with the height direction of the roll perpendicular to the ground, and an evaluation was made as to whether the roll shape was maintained (presence or absence of deviation of 3 mm or more).
⊚: The roll shape was maintained for 9 to 10 rolls.
◯: The roll shape was maintained for 7 to 8 rolls.
Δ: The roll shape was maintained for 5 to 6 rolls.
x: The rolled shape was maintained for 3 to 4 rolls.
XX: The rolled shape was maintained for 2 to 0 rolls.

(cosmetic)
Twenty monitors visually evaluated the appearance of the kitchen towel rolls by selecting "good" or "bad." The evaluation criteria were as follows, with ◎, ○, and △ being considered acceptable.
◎: When 18 to 20 people answered "good."
○: When 14 to 17 people answered "good."
△: When 10 to 13 people answered "good."
×: When 6 to 9 people choose "Good."
××: When there are no "good" answers or there are between 1 and 5 people.

(Water absorption)
When using the kitchen towel sheet, the monitors were asked to evaluate whether the sheet was able to wipe away water sufficiently by selecting "sufficient" or "insufficient." The evaluation criteria were as follows, with ◎, ○, and △ being considered as passing.
◎: When "sufficient" is between 18 and 20 people.
○: When "sufficient" is between 14 and 17 people.
△: When "sufficient" is between 10 and 13 people.
×: When "sufficient" is between 6 and 9 people.
××: When there are not enough people or there are more than 1 person but less than 5 people.

(wipeability)
The monitors evaluated the ease of wiping when using the kitchen towel sheet by selecting "easy" or "difficult." The evaluation criteria are as follows, with ◎, ○, and △ being considered pass.
◎: When 18 to 20 people say it's "easy."
○: When 14 to 17 people say it's "easy."
△: When 10 to 13 people say it's "easy."
×: When 6 or more but less than 9 people say "easy."
××: When there are no "easy" people or when there are between 1 and 5 people.

The results obtained are shown in Tables 1 to 3.

From the above, it can be seen that the kitchen towel roll of the present invention is bulky, has good aesthetic appeal and a pleasant feel when used, and retains its rolled shape well.

1 Kitchen towel roll 1a Surface 1b Back surface 1e Outer edge of outermost roll of kitchen towel sheet 1x Kitchen towel sheet 40 Measuring device 41 Base portion 42a, 42b Support rod 43 Movable weight mounting plate 44 Weight 200 Test piece 200a, 200d Corner portion 210 Band 220 Holder

Claims (4)

A kitchen towel roll is formed by laminating two plies of sheets each having an embossed pattern and bonding them with glue, and the resulting kitchen towel sheet has a specific volume of 7 cm ³ /g or more and 22 cm ³ /g or less, and is wound into a roll.
The kitchen towel sheet has a concave-convex pattern derived from a papermaking process that is different from the embossed pattern,
the embossing pattern is a linear embossing pattern,
In the linear embossing pattern, for embossments having a thickness of 0.1 mm or more and 4 mm or less and a length of 5 mm or more, the total length when the lengths of the embossments are added is 50 cm/100 cm2 ^or more and 550 cm/100 cm2 ^or less,
the basis weight of two plies of the kitchen towel sheet is 30 g/m or more ^and 54 g/m ^or less, and the root mean square height of the surface roughness in the portion where the embossed pattern is not provided is 35 μm or more and 170 μm or less;
The looseness of the outer portion of the kitchen towel roll (a position corresponding to 10% of the length from the outer edge of the outermost turn of the kitchen towel roll when the kitchen towel roll is unwound) is 5 mm or more and 15 mm or less, and the looseness of the inner portion of the roll (a position corresponding to 90% of the length from the outer edge of the outermost turn of the kitchen towel roll when the kitchen towel roll is unwound) is 2 mm or more and 10 mm or less,
A kitchen towel roll characterized in that the winding density of the kitchen towel roll is 0.28 m/cm ² or more and 0.40 m/cm ² or less . The kitchen towel roll of claim 1, wherein the embossing depth in the embossing pattern is 0.06 mm or more and 1.1 mm or less. The kitchen towel roll according to claim 1 or 2, characterized in that the area ratio of the convex portions on the embossing roll used to apply the embossing pattern is 4% or more and 40% or less. 4. The kitchen towel roll according to claim 1 , wherein the ratio of the embossing depth in the embossing pattern to the overall paper thickness of the kitchen towel sheet is 0.02 or more and 0.4 or less.