WO2024070045A1

WO2024070045A1 - Kitchen paper roll

Info

Publication number: WO2024070045A1
Application number: PCT/JP2023/019280
Authority: WO
Inventors: 壮真亀星
Original assignee: 大王製紙株式会社
Priority date: 2022-09-30
Filing date: 2023-05-24
Publication date: 2024-04-04
Also published as: JP2024052108A

Abstract

[Problem] To provide a kitchen paper roll having excellent design and oil absorption properties even when the winding length is long. [Solution] The above problem is solved by a kitchen paper roll obtained by rolling kitchen paper in which sheets with a basis weight of 15.0 to 23.0 g/m² per ply are laminated in two plies and on which there are relief features produced by embossing, the kitchen paper roll being such that the rolling length is 22 to 32 m (pitch × number of cuts), the paper thickness is 1.5 mm per five sheets to 2.2 mm per five sheets, the embossing is of a tip-to-tip form in which the tops of convex parts on the respective sheets face each other, and the value of the ratio (D obverse/D reverse) between the embossing depth (D obverse) of the concave parts on the outer surface side of the rolling and the embossing depth (D reverse) of the concave parts on the inner surface side of the rolling is 1.2 to 1.7.

Description

Kitchen Paper Roll

The present invention relates to a kitchen paper roll.

In recent years, paper roll products have become longer. The same is true for kitchen paper rolls, which are made by rolling up paper towels. This is due to the advantages of being easy to carry after purchase, having the benefit of having to purchase and replace them less frequently, and being convenient in terms of storage space.

JP 2020-044385 A

To increase the length, the roll diameter can be increased, but this increases portability and space required for storage and sale, so it is desirable to increase the length while keeping the roll diameter at the same level as conventional products.

In order to increase the length without increasing the diameter, it has been considered to reduce the basis weight, thickness and tightly wind the roll, but simply reducing the basis weight, thickness and tightly winding the roll makes the sheet thin and prone to tearing, and the difference in quality with conventional non-long products can cause dissatisfaction among consumers.

Some kitchen paper has a textured surface created by embossing to improve design and liquid absorption. If the roll is tightly wound, the texture and gaps between the sheets can get crushed, and the desired design, absorbency, and other qualities cannot be achieved.

The main objective of the present invention is to provide a kitchen paper roll that has sufficient quality in terms of design and liquid absorption, prevents the roll from becoming too large when extended, and has unevenness due to embossing.

The kitchen paper roll that solves the above problems has the following features.
A sheet having a basis weight of 15.0 to 23.0 g/ ^m2 is laminated to two plies,
A kitchen paper roll in which the kitchen paper having embossed projections and recesses is wound up,
The roll length is 22 to 32 m (pitch x number of cuts), and the paper thickness is 1.5 mm/5 sheets to 2.2 mm/5 sheets.
The embossing is in a tip-to-tip form in which the tops of the protrusions of the sheets face each other,
the ratio (D front/D back) of the embossed depth of the recess on the unwinding surface side (D front) to the embossed depth of the recess on the winding inner surface side (D back) is 1.2 to 1.7;
This is a kitchen paper roll characterized by the above.

The present invention makes it possible to provide a kitchen paper roll that has sufficient quality in terms of design and liquid absorption, prevents the roll from becoming too large in diameter due to length, and has unevenness due to embossing.

FIG. 1 is a schematic explanatory diagram of a kitchen paper roll. FIG. 4 is a partial plan view of an embossment according to the embodiment. FIG. 4 is a partial cross-sectional view of an embossment according to an embodiment. 1A and 1B are a schematic plan view and a schematic cross-sectional view of a portion for explaining embossing depth measurement.

Next, embodiments of the present invention will be described in detail below with reference to the drawings.
As shown in FIG. 1, a kitchen paper roll 1 is formed by winding two plies of belt-shaped kitchen paper 10 around a paper tube (also called a tube core) 20 in a roll shape.

The winding length is 20 to 32 m, preferably 25 to 28 m. The winding diameter L2 is preferably 105 to 125 mm, and more preferably 110 to 120 mm.

While commercially available 2-ply kitchen paper rolls 1 are generally around 10 to 15 m long, the kitchen paper roll 1 of the present invention has a fairly long roll length of 22 to 32 m and a preferred roll diameter L2 of 105 to 125 mm, making it easy to carry after purchase and convenient in terms of storage space.

The winding length of a kitchen paper roll is a value calculated by multiplying the cutting pitch by the number of cuts. The kitchen paper roll 1 has perforations 12 formed so that it can be easily cut at predetermined intervals for easy use like sheets. The distance L4 between these perforations 12 is the cutting pitch. The cutting pitch is approximately 18 to 25 cm. The kitchen paper roll of this embodiment also falls within this range.

The number of cuts is the number of kitchen paper sheets obtained by cutting along the perforations 12, and corresponds to the number of sheets. A conventional kitchen paper roll 1 has about 50 to 70 cuts. In this embodiment, the desired number of cuts is 90 to 180 cuts, and more preferably 100 to 140 cuts. Increasing the number of cuts makes the roll longer.

The winding diameter L2 is calculated by measuring the circumference of the roll at three points in the width direction using a diameter rule (Muratec KDS Co., Ltd.) and taking the average of the three measurements.

The roll width L1 is not limited, but can be 200 to 230 mm, which is similar to commercially available products. The roll width is calculated by measuring the axial length of the outer peripheral surface of the roll at three points around the roll using a JIS Class 1 metal ruler and averaging the measured values.

The paper tube diameter L3 is not necessarily limited, but is set to 35 to 45 mm. The paper tube diameter is a factor in adjusting the winding density, which will be described later. The paper tube diameter is calculated by measuring the circumference of the paper tube at three points in the width direction using a diameter rule (Muratec KDS Co., Ltd.) and taking the average value of the three points.

The kitchen paper 10 according to this embodiment is formed by laminating two plies of

crepe paper sheets

10A and 10B, and the

sheets

10A and 10B have unevenness due to embossing. The embossing is preferably a steel rubber type embossing. As shown in FIG. 2, the embossing is a tip-to-tip form in which the top of the convex portion 11A of the first sheet 10A constituting one side of the kitchen paper 10 faces the top of the convex portion 11B of the second sheet 10B constituting the other side. Another known form of embossing is a nested form in which the top of the convex portion of the first sheet constituting one side of the kitchen paper faces the non-convex portion of the second sheet constituting the other side. In the nested form, the convex portions of the sheets do not face each other, so the bulk (thickness) of the sheet can be suppressed without reducing the sheet basis weight, compared to the tip-to-tip form. Although it seems to be suitable for long lengths, the gap between sheets becomes narrower, so the oil absorption tends to be low. In particular, when the sheet is wound tightly due to long lengths, the gap between the sheets is easily crushed, and the tendency for the oil absorption to decrease is thought to be more pronounced.

In the case of kitchen paper, the first sheet 10A and the second sheet 10B may be integrated by being glued at the tops of the convex parts that contact each other. The adhesive paste 10C may be a known adhesive paste used in kitchen paper with a laminated structure. For example, it may be a cellulose-based adhesive such as polyvinyl alcohol, starch, modified starch, or carboxymethyl cellulose.

The kitchen paper roll 1 of this embodiment adopts a tip-to-tip embossing form, which tends to make the kitchen paper 10 bulky and difficult to lengthen, and has been devised to suppress the increase in diameter due to lengthening while maintaining sufficient quality in terms of design and liquid absorption. That is, the kitchen paper roll 1 of this embodiment has a tip-to-tip embossing form in which the tops of the

convex parts

11A, 11B of the

sheets

10A, 10B face each other, and the ratio (D front/D back) of the embossing depth of the concave part 13A on the unwinding surface side (D front: indicated by reference character L6 in FIG. 2) to the embossing depth of the concave part 13B on the winding inner surface side (D back: indicated by reference character L7 in FIG. 2) is 1.2 to 1.7. In FIG. 2, the first sheet 10A is the unwinding surface side, and the second sheet 10B is the winding inner surface side (the side closer to the paper tube). This difference in depth can be achieved by varying the embossing depth of the recesses, and methods for this include, for example, embossing the sheet using a metal embossing roll with a different engraving (mainly the height of the protrusions), varying the nip width (nip pressure) during embossing, or changing the way the marriage roll or nip roll is applied to the front and back when laminating the sheets. In particular, it is desirable to apply the marriage roll to the second sheet 10B on the inside side of the roll after lamination. However, the method is not limited to these exemplary methods.

This configuration is believed to result in less unevenness caused by embossing and less crushing of gaps between sheets due to tight winding caused by longer lengths in the kitchen paper roll 1, while ensuring the design (embossing clarity) of the sheet 10A on the unrolling side and minimizing the decrease in oil absorption. It is also believed that the difference in depth of the embossed recesses on the front and back of the base paper creates tension differences and deformation between the front and back of the sheet when wound, making it easier to wind into a roll.

The specific values of the embossing depth of the recesses 13A on the unwinding surface side (D front) and the embossing depth of the recesses 13B on the winding inner surface side (D back) are not necessarily limited, but the embossing depth of the recesses 13A of the first sheet 10A on the unwinding surface side (D front) is preferably 0.060 to 0.765 mm, more preferably 0.102 to 0.493 mm, and particularly preferably 0.120 to 0.255 mm. The embossing depth of the recesses 13B of the second sheet 10B on the winding inner surface side (D back) is preferably 0.050 to 0.450 mm, more preferably 0.085 to 0.290 mm, and particularly preferably 0.100 to 0.150 mm. Within these ranges, it is easy to ensure design and oil absorption.

The depth of the embossed

recesses

13A, 13B is measured using a one-shot 3D measuring macroscope VR-3200 or equivalent manufactured by Keyence Corporation, and image analysis software "VR-H1A" or equivalent software. Measurements are performed at a magnification of 12x and a field of view of 24mm x 18mm. However, the magnification and field of view can be changed as appropriate depending on the size of the embossment (recess). The emboss depth is determined by measuring the line roughness. The specific measurement procedure is described with reference to Figure 4. Using the above software, an "emboss depth (measurement curve) profile Q2" is obtained for a line segment Q1 that crosses the longest part of the periphery of one of the

recesses

13A, 13B in the image area (part X in the figure) shown in a plan view. From the "emboss depth (measurement curve) profile Q2" of the image portion (Y portion in the figure) shown at this viewpoint, two recess edge points P1 and P2 that are convex upward and have the strongest curve are extracted, and the minimum depth value of the portion sandwiched between the recess edge points P1 and P2 is calculated and set as the minimum depth value Min. Furthermore, the average value of the depth values of the recess edge points P1 and P2 is set as the maximum depth value Max. Then, the emboss depth is calculated as the maximum value Max - minimum value Min. However, the "emboss depth (measurement curve) profile Q2" is set as a profile curve after correction with "automatic correction" for the inclination correction in consideration of the waviness of the sheet. The measurement is made as the recess depth, taking the average value of 10 points at a position 10% from the outermost end at the beginning of use. The two recess edge points P1 and P2 that are convex upward and have the strongest curve are selected by visual inspection. Note that the selection may be made with reference to the contour E in the image of the

recesses

13A and 13B being measured from the planar viewpoint.

The kitchen paper 10 of the embodiment is embossed, but the embossing pattern is not necessarily limited. The embossing can be any suitable embossing pattern. As an example of a preferred embossing pattern, as shown in FIG. 3, a pattern having a substantially rectangular embossed section 40 in which a plurality of recesses are arranged and a non-embossed section 50 located between the sections can be exemplified. The shape of the embossed section can be a square, a rectangle, a diamond, a circle, or the like. The area of one embossed section 40 is not necessarily limited, but can be exemplified as 3 to 16 ^cm2 . The number of

recesses

13A, 13B in the embossed section can be exemplified as about 10 to 100. The non-embossed section 50 is a portion between the embossed sections 40 with no recesses and a width L8 of 3.0 to 10.0 mm.

The kitchen paper 10 according to the embodiment has a basis weight of 15.0 to 23.0 g/ ^m2 per ply. Preferably, it is 16 to 21 g/ ^m2 . The basis weight is based on JIS P 8124 (1998). However, the basis weight value is determined by measuring the basis weight of the kitchen paper 10 and dividing it by the number of layers, i.e., two sheets. This basis weight range is low for kitchen paper. If the basis weight is too thick, the roll length must be shortened, and conversely, if the basis weight is too low, the strength is reduced and the paper is easily felt thin when used. In the kitchen paper 10 according to the embodiment, due to the configuration of the recesses described above, even if the basis weight is low, the design of the recesses and the amount of oil absorption are sufficient.

The kitchen paper 10 according to the embodiment has a paper thickness of 1.5 mm/5 sheets to 2.2 mm/5 sheets. This paper thickness is measured by stacking the next 5 cuts, excluding the first cut from the end of the roll. The paper thickness when 5 sheets are stacked (10 plies) is less affected by the crushing of unevenness caused by the embossing process when measuring. However, if the paper thickness when 5 sheets is too thick, the roll length must be shortened, and conversely, if it is too thin, it will result in a decrease in strength and the thinness of the paper will be felt when using it. The paper thickness is measured by thoroughly conditioning the humidity of the test piece under the conditions of JIS P 8111 (1998), and then measuring under the same conditions using a dial thickness gauge (thickness measuring device) "PEACOCK G type" (manufactured by Ozaki Manufacturing Co., Ltd.). The paper thickness is measured without peeling off each ply. The specific measurement procedure is to make sure that there is no dirt or dust between the plunger and the measuring table, lower the plunger onto the measuring table, move the scale of the dial thickness gauge to set the zero point, then raise the plunger and place the sample on the test table, slowly lower the plunger, and read the gauge at that time. At this time, the plunger is simply placed on the table. The plunger terminal is made of metal, and the circular flat surface with a diameter of 10 mm is made to contact the paper surface perpendicularly, and the load when measuring this thickness is about 70 gf at 120 μm. The thickness is the average value obtained by performing 10 measurements. In the embodiment, when the value of the paper thickness per sheet of kitchen paper is used, for example, the value in the calculation of the roll density is the value obtained by dividing the value of 5 sheets by 5.

Due to the above-mentioned configuration, particularly the embossing characteristics, the kitchen paper 10 according to the embodiment achieves a high oil absorption value (oil absorption value) of 33.0 to 43.0 according to the following formula (1): Formula (1)... [oil absorption value (oil absorption value)] = oil absorption amount [g/ ^m2 ] × [roll density] / 1 ply per U.S. basis weight (g/ ^m2 ). Roll density is calculated as follows: (paper thickness of 2 plies × roll length) / ((radius of roll diameter) ² ×π - (radius of paper tube diameter) ² ×π).
That is, if the roll density is high, the roll will be tightly wound, and the unevenness caused by the embossing will be easily crushed, resulting in a decrease in oil absorption. On the other hand, even if the roll density is improved by reducing the paper thickness by decreasing the basis weight, the oil absorption will also decrease due to the lower basis weight. Therefore, taking these points into consideration, if the value of the oil absorption performance (oil absorption performance value) is within the above range, it can be said that the oil absorption performance of the kitchen paper roll as a whole is high. A comparison with commercially available and conventional products will be made later.

The roll density of the kitchen paper roll 1 of this embodiment is not limited, but is preferably 1.20 or less, and more preferably 0.95 to 1.19. If the roll density is too high, the embossing is likely to be crushed, as mentioned above. This is particularly true in the case of double embossing.

The oil absorption amount in the embodiment is measured as follows (1) to (5).
(1) After curing the test piece in a dryer at 105° C. for 3 minutes, the mass of the test piece is measured using an electronic balance (such as A&D HR300). The size of the test piece is 100 mm×100 mm.
(2) In a tray larger than the test specimen (for example, inner dimensions: 215 mm x 160 mm), salad oil (Nissin salad oil: manufactured by Nisshin Oillio Group, Ltd.) at 25°C is poured to a depth of about 20 mm.
(3) The test piece is spread out on a rigid flat net (e.g., 120 mm x 120 mm, mesh size 30 mm) that is larger than the test piece, and then lowered into the tray containing the salad oil so that the test piece is immersed in the oil so that it comes into contact with the oil surface.
(4) When the salad oil has soaked into the surface of the test piece, raise the flat net directly above the oil surface, leave it there for 26 to 27 seconds, then pick up a corner of the test piece with tweezers and transfer the test piece to a pre-weighed measurement container. At this time, do not allow more than 30 seconds from when the flat net is raised above the oil surface and left at rest until it is transferred to the measurement container.
(5) The mass of the measuring vessel containing the test piece is measured using an electronic balance, and the mass of the test piece after oil absorption is calculated by subtracting the mass of the measuring vessel from the measured value. The amount of oil absorption per ^m2 is then calculated using the following formula.
Oil absorption (g/ ^m2 ) = ((mass of oil-absorbed test piece measured in (4) above) - (mass of test piece after 3 minutes curing measured in (1) above)) x 100 (Note: one test piece is 100 ^cm2 x 100)

The tensile strength of the kitchen paper 10 of the embodiment is not necessarily limited, but the tensile strength in the longitudinal direction is preferably 650 to 1350 cN/25 mm, more preferably 780 to 1220 cN/25 mm, and the tensile strength in the transverse direction is preferably 250 to 550 cN/25 mm, more preferably 320 to 480 cN/25 mm. The tensile strength refers to the tensile strength when dry (dry tensile strength). If the tensile strength is within this range, it can be said that the strength is necessary when in use.
The tensile strength is measured in accordance with JIS P 8113:2006 using a test piece having a paper width of 25 mm.

The fiber material of the

sheets

10A and 10B in the embodiment is pulp fiber, and the pulp composition can be a known composition for kitchen paper 10. It is preferable that the composition contains 90 to 100% by mass of virgin pulp. A pulp composition that exhibits the unique effects of the present invention is one in which softwood pulp such as NBKP (softwood kraft pulp) or NUKP (softwood unbleached pulp) is mixed with hardwood pulp such as LBKP (hardwood kraft pulp) or LUKP (hardwood unbleached pulp) in an appropriate ratio. It is preferable that the pulp composition contains more softwood pulp than hardwood pulp. In particular, it is preferable that the ratio of softwood pulp to hardwood pulp is 50:50 to 80:20. Since softwood pulp has longer fibers than hardwood pulp, liquids tend to spread along the long softwood pulp fibers in pulp compositions that contain a large amount of softwood pulp, making the effects of the present invention particularly likely to be realized. In addition, the paper tends to develop a firm stiffness, making it particularly suitable for use in kitchen paper used for wiping off and absorbing liquids.

The effects of the kitchen paper roll according to the present invention will be further explained below with reference to examples and comparative examples of kitchen paper roll 1.

The toilet paper in each example was extracted from kitchen paper. The physical properties and composition of each example are shown in Table 1.

Furthermore, a sensory evaluation test was conducted to compare Example 2 and Comparative Example 4 with regard to the clarity of the embossing on the sheet on the unwound surface. The test was conducted by 17 people, and the average of the scores of the 15 people excluding the highest and lowest scores was used as the evaluation score. The evaluation was conducted by using Comparative Example 4 as the standard and evaluating Example 2. In other words, scores were assigned as follows: 4 points for the same as Comparative Example 4, 5 points for slightly good, 6 points for good, 7 points for very good, 3 points for slightly poor, 2 points for poor, and 1 point for very poor, and the average was calculated to make a judgment.

According to the results in Table 1, the Examples tend to have a higher oil absorption than the nested Comparative Examples 1, 2, 5, and 6, which have higher basis weights. In the nested cases, the winding length is about 21 m, and in Comparative Example 1, which has deep embossed recesses, it is about the same as Example 1, which is over 26 m. In the nested cases, it tends to be difficult to achieve a sufficient length and oil absorption.
Furthermore, in the examples, the depth of the embossed recesses is shallow and the basis weight is low, but the oil absorption is more sufficient than in the comparative examples.
Looking at the oil absorption performance values, Comparative Example 2 has a high basis weight and a long winding length, but is nested, so the oil absorption performance is low when viewed as a whole roll. Comparative Example 3 has a high basis weight and is tip-to-tip, but is short in winding length, so the oil absorption performance is low when viewed as a whole roll.
In addition, comparing the working example with Comparative Example 4, Comparative Example 4 has a lower oil absorption. Even in the case of tip-to-tip, it is considered that the oil absorption decreases when the winding length is increased simply by reducing the basis weight. In addition, the oil absorption performance of the entire roll is not sufficiently improved. The embossing is crushed and the embossed shape is distorted, but it is also considered that the paper layers are close to each other in the parts other than the recessed parts due to the embossing, that is, the gap between the sheets is crushed.
In addition, the result regarding the clarity (design) of the embossment on the surface layer gave Example 2 a score of 4.6 points, exceeding that of Comparative Example 4. The sum of the depths of the recesses on the front and back was deeper in Comparative Example 4, but the results showed that the embossment of Example 2 was clearer.
As shown in the above embodiments, the configuration of the present invention can provide a kitchen paper roll that has sufficient quality in terms of design and liquid absorption, is prevented from becoming larger in diameter due to lengthening, and has unevenness due to embossing.

The kitchen paper roll of the present invention can be used for home use as well as commercial use (for example, in airport cafeterias and hospitals used by an unspecified number of people).

1...kitchen paper roll, 10...kitchen paper, 10A, 10B...crepe paper, 12...perforation, 20...paper tube (tube core), L2...winding diameter (diameter) of kitchen paper roll, L3...diameter of toilet roll tube core, L1...width of kitchen paper roll, L4...cut pitch, 10C...adhesive glue, L6...D front, L7...D back 40...embossed section, 50...non-embossed section,
11A, 11B...convex portions, 13A, 13B...concave portions, L8...width of non-embossed section.

Claims

A sheet having a basis weight of 15.0 to 23.0 g/ m2 is laminated to two plies,
A kitchen paper roll in which the kitchen paper having embossed projections and recesses is wound up,
The roll length is 22 to 32 m (pitch x number of cuts), and the paper thickness is 1.5 mm/5 sheets to 2.2 mm/5 sheets.
The embossing is in a tip-to-tip form in which the tops of the protrusions of the sheets face each other,
the ratio (D front/D back) of the embossed depth of the recess on the unwinding surface side (D front) to the embossed depth of the recess on the winding inner surface side (D back) is 1.2 to 1.7;
The kitchen paper roll is characterized by the above.