JP7659965B2 - Toilet roll - Google Patents

Description

The present invention relates to toilet rolls.

There are a variety of toilet rolls on the market, differing in factors such as the number of plies, whether or not they are embossed, basis weight, paper thickness, roll length, and roll density.

One of these is a group of products that are considered long-length rolls. In other words, the basis weight per ply is not particularly low, and although it is two plies, the roll length is long and double embossed to give it a soft feel. An example of this is the product in Patent Document 1.

JP 2014-188342 A

However, in this type of long rolled product, the sheet tends to become thin and hard. When the sheet becomes hard, not only does it lose the necessary properties such as softness, but it also becomes more prone to breaking.

The main objective of the present invention is to provide a toilet roll that is soft enough and resistant to breaking even though it is a long roll.

In order to solve the above problems, the present invention provides a sanitary tissue paper roll in a two-ply stacked state,
The basis weight per ply is 10.0 to 15.0 g/m ² , the paper thickness per ply is 60 to 95 μm, the outer diameter of the paper core is 20 to 45 mm, and the winding length for two plies is 60 to 90 m;
Furthermore, the tensile modulus per ply is 6.0 to 16.0 N/mm ² and the work at break is 3.0 to 6.0 N·mm;
An embossment is formed on each of the plies, and these are laminated to form a double embossment.
The embossing pattern is a pattern in which embossing recesses each having a rectangular shape in a plan view are arranged in a lattice shape with centers spaced apart from each other in the width direction and the continuous direction of the ply,
A valley groove is formed so as to connect the corner of the recess to the corner of the adjacent recess.
This is a toilet roll characterized by the above.
The tensile modulus and breaking work are values measured in the longitudinal direction of the fiber, and are values measured on a 25 mm wide sample with a gripping jig distance of 50 mm in a tensile tester at a pulling speed of 10 mm/min.

The present invention makes it possible to provide a toilet roll that is soft and resistant to breaking even when rolled into a long length.

FIG. 1 is a diagram showing the results of a tensile test in Comparative Example 1. FIG. 2 is a diagram showing the results of a tensile test in Example 1. FIG. 1 is a schematic perspective view of a toilet roll. FIG. 11 is a plan view of an example of an embossing pattern. FIG. 5 is a cross-sectional view of a main part taken along the line in FIG. 4 .

The present invention will be explained in more detail below while explaining the embodiments of the present invention.

As shown in FIG. 3, the toilet roll of the present invention is formed by winding a strip of toilet paper 10 around a paper tube (also called a tube core) 20 into a roll to form a toilet roll 1.

This toilet paper uses 100% by mass of virgin pulp as the fiber material, and can also contain recycled paper pulp.
For example, the fiber material may be 30 to 70% by mass of virgin pulp and 30 to 70% by mass of recycled paper pulp. Recycling paper pulp is cheaper than virgin pulp, and by blending recycled paper pulp, the fiber material can be produced more cheaply than one made of 100% by mass of virgin pulp.

The recycled paper pulp is not necessarily limited, but it is particularly desirable to use high-quality recycled paper pulp (also called F-DIP, high-quality recycled paper pulp, or high-quality deinked pulp) made from high-quality recycled paper. High-quality recycled paper pulp is made from selected high-quality recycled paper such as high-quality paper, colored high-quality paper, and slightly glossy paper, and contains a large amount of hardwood kraft pulp (LBKP) derived from the raw material. This makes it easy to develop paper strength, and in particular makes it extremely easy to configure the basis weight, paper thickness, dry tensile strength, roll diameter, and roll density of the toilet paper.

The toilet paper according to the present invention is preferably made of the above-mentioned fiber material and has a basis weight (basis weight per ply) of 10.0 to 15.0 g/m ² , and more preferably 11.0 to 14.0 g/m ^2. First, if the basis weight is too small, it is difficult to achieve the necessary strength and paper thickness. Also, if the basis weight is too large, the paper thickness becomes too thick, making it difficult to achieve the desired compact roll diameter range.
The basis weight is a value measured based on JIS P 8124 (1998).

The paper thickness per ply is set to 60-95 μm, with 70-90 μm being particularly desirable. If the paper is too thin, it will be difficult to ensure the necessary strength, and the paper will lose stiffness and feel, particularly its fluffy feel. It will also be difficult to achieve an appropriate roll diameter and firmness for the product. Conversely, if the paper is too thick, it will be difficult to achieve the desired roll diameter, making it difficult to achieve compactness.

The paper thickness is measured by thoroughly conditioning the test piece under the conditions of JIS P 8111 (1998) (usually for about 8 hours), and then measuring the thickness of one ply under the same conditions using a dial thickness gauge (thickness measuring device) "PEACOCK G type" (manufactured by Ozaki Manufacturing Co., Ltd.). Specifically, after making sure that there is no dirt or dust between the plunger and the measurement table, the plunger is lowered onto the measurement table, the dial thickness gauge's scale is moved to set the zero point, the plunger is then raised and the sample is placed on the test table, the plunger is slowly lowered and the gauge at that time is read. At this time, the plunger is simply placed on the test 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 during the paper thickness measurement is about 70 gf. The paper thickness is the average value obtained by performing 10 measurements. The dry tensile strength according to the present invention is specified in JIS P 8113.

The outer diameter of the paper tube is preferably 20 to 45 mm, and more preferably 35 to 45 mm. The outer diameter of the paper tube is not fundamentally related to the characteristics of the toilet paper, but is regulated by factors related to the winding length and winding density of two plies.

The winding length for two plies is 60 to 90 m, with 65 to 85 m being particularly desirable.

The toilet paper in the embodiment is made of a fiber material composition of virgin pulp and, if necessary, recycled paper pulp, and has a basis weight, paper thickness, paper tube outer diameter, and roll length in two plies, so that, despite its long length, it can easily fit into a commercially available toilet roll holder and can be easily removed from the holder.
In addition, these "fit" and "ease of removal" are evaluated as "ease of hanging" and "ease of turning" in the test results described below.

The toilet paper of the present invention has a tensile modulus per ply of 6.0 to 16.0 N/mm ² , more preferably 6.5 to 10.0 N/mm ² , and a breaking work of 3.0 to 6.0 N·mm, more preferably 3.5 to 5.5 N·mm, and is a paper that satisfies softness and is difficult to break.
The tensile modulus and breaking work are values measured in the longitudinal direction of the fiber, and are values measured on a 25 mm wide sample with a gripping jig distance of 50 mm in a tensile tester at a pulling speed of 10 mm/min.

In addition, it is more desirable for the elongation at break to be 6.0 to 12.0%.

There are long-length commercially available products that have similar values for basis weight and thickness. However, the tensile modulus and work of rupture of these commercial products are different.

Typically, the tensile test results for Comparative Example 1 are shown in Figure 1, whereas the tensile test results for Example 1 are shown in Figure 2.

A supplementary explanation regarding this test will be given below.
That is, when a toilet paper sheet is gently touched, if the sheet is stretchy, the stress from the sheet is reduced and the user feels that the sheet is soft.
In this way, assuming "gently touching the sheet", the optimum method for determining the quality of the sheet is to set the tensile speed of the gripping jig in the tensile tester to 10 mm/min and obtain the tensile modulus value at a displacement of 0. The displacement of 0 is defined as the point where the elongation (stroke) is 0 when the load is 0.2 N using a 25 mm wide sample in accordance with JIS P 8113.
Usually, the tensile strength is measured at a pulling speed of 100 mm/min, and the breaking elongation is larger in Comparative Example 1. This is because the breaking strength of the sheet is high, and the sheet (paper quality) is hard, which is different from the elongation of the soft sheet shown in Example 1, as shown in FIG.

Furthermore, when the tensile speed was 10 mm/min, the work to break for Example 1 was higher than that for Comparative Example 1, and it can be said that Example 1 was less likely to break due to elongation.

A sheet having a tensile modulus of elasticity of 6.0 to 16.0 N/mm ² and a breaking work of 3.0 to 6.0 N·mm per ply can be said to be a paper that satisfies the softness requirements and is difficult to break.
In fact, the evaluation based on the tensile modulus and work of break values has a high correspondence with the sensory evaluation, as will be shown in the test evaluation described later.

Methods for obtaining toilet rolls that are long yet soft and resistant to breaking include, for example, using a calendar in a ply machine to iron the crepe shape, so that the stretch caused by the crepe is maintained even after processing, and devising an embossing method.

Regarding embossing, further examples include the ridges of the embossing that partially destroy the fibers relative to the overall flow, making the material stretchable and shrinkable under a small load (provisionally named "Mt. Fuji embossing"); and the embossing can be double embossed.
When double embossing is used, there is a gap between the sheets and both the front and back are smooth, resulting in a soft and smooth quality.In contrast, with single embossing, which is commonly used for long products, it is difficult to obtain a product with sufficient softness, as will be shown in the test examples described later.

In the embodiment, the winding density of the toilet roll is preferably 1.0 to 1.8, and more preferably 1.2 to 1.7. If the winding density is low, the roll is loosely wound and the texture can be maintained, but the winding length is short compared to the roll diameter, resulting in excessive logistics costs. Conversely, if the winding density is high, the texture will be significantly reduced. The winding density is calculated as described below.

On the other hand, in the toilet paper according to the present invention, a softener can be blended to adjust the paper strength and improve the surface properties. However, the softener here is not an externally applied agent to the toilet paper like a moisturizer or lotion, but is an internally added agent to the papermaking raw material. With an externally applied agent like a lotion, the paper strength decreases when the agent is applied, making it difficult to wind the paper at a high tension to compact it, making production extremely difficult. In addition, it is difficult to achieve the desired winding density and to keep the price low. The blending amount of the softener is preferably 0.8 to 2.0 kg/t. A preferred softener contains a nonionic surfactant (component A) having an alkyl group and/or an alkenyl group and a cationic surfactant (component B) having an alkyl group and/or an alkenyl group. In particular, it is desirable for the nonionic surfactant (component A) to have an alkyl group having 6 to 24 carbon atoms and/or an alkenyl group having 6 to 24 carbon atoms as a hydrophobic portion. If the carbon number of the A component is less than 6, the softening effect may not be enhanced, and if the carbon number exceeds 24, dispersibility may be poor when added to a papermaking system.

In addition, when manufacturing the toilet paper of the present invention, the fiber raw material can be beaten as appropriate, but with the toilet paper of the present invention, the beating process can be omitted by blending recycled paper pulp.

The crepe ratio during papermaking can also be set appropriately. A crepe ratio of 15-27% is preferable, and 18-23% is more preferable. When processing into rolls, the winding diameter may be adjusted by draw or tension, so by setting the crepe ratio within the above range, the paper is less likely to tear even when moderate draw or tension is applied, and the paper does not become excessively thick, making it preferable.

Furthermore, it is preferable that the toilet paper is embossed. The embossing can be a suitable embossing pattern such as a micro embossing, a dot embossing, or a design embossing. However, when embossing is applied, the depth of the embossing pattern is preferably 1.90 mm or less. More preferably, it is preferably within the range of 0.7 mm to 1.90 mm. If it is deeper than 1.90 mm, it becomes difficult to make it compact. Also, if the embossing depth is shallower than 0.75 mm, the bulkiness and design due to the embossing tend to be insufficient.
It should be noted that the dimensions of the embossing refer to the actual dimensions of the convex portions formed on an embossing (metal) roll, and do not refer to the embossing imparted to actual paper, since the mating surface of the embossing roll is an elastic roll made of rubber or the like.
A preferred example of the embossment is one in which depressions with square bottoms are arranged so that each vertex of the positive bottom of the depression is connected to the vertex of the square bottom of the adjacent depression by a valley line, as in the above-mentioned "Mt. Fuji embossment." This embossment is likely to produce the desired effect of obtaining a sheet with soft and smooth quality.

A specific example of the aforementioned "Mt. Fuji embossing" is shown below.
As shown in Figures 4 and 5, the "Mt. Fuji embossment" has rectangular-bottom recesses 40, 40 arranged in a lattice pattern across the entire surface of the page at a predetermined center distance L9, and valley grooves 41, 41... are formed connecting the four corners of the bottom surface.
It is particularly desirable for the "Mt. Fuji embossment" to have a rectangular bottom surface of 1.0 to 1.5 x 1.0 to 1.5 mm, a center distance L9 of 4.5 to 5.5 mm, and the recesses 50, 50... to be arranged in a lattice pattern at an angle of 40° to 50° with respect to the width direction (the angle is indicated by the symbol ∠B in FIG. 4).

The "Mt. Fuji embossing" can be achieved in a so-called single embossing form, where a concave portion on one side becomes a convex portion on the other side, but it is preferable to achieve a so-called double embossing form, where both sides become concave.

The toilet roll according to the present invention can be manufactured by winding the toilet paper base paper obtained in the papermaking process in accordance with known manufacturing procedures. More specifically, in the paper tube forming process for manufacturing a long paper tube, a long paper tube is manufactured, the toilet paper manufactured in the papermaking process is wound around this long paper tube to manufacture a log, and this log is then cut in the width direction to the product width (width of symbol L3 in FIG. 3) to make individual toilet rolls. In particular, when manufacturing the log, the toilet roll can be manufactured by adjusting the tension when winding the toilet paper around the paper tube.

Next, examples and comparative examples of the toilet roll of the present invention will be shown to clarify the effects of the present invention.

The configuration of the toilet roll and the physical properties and composition of the toilet paper for each example are as shown in Table 1 below.

The fiber material is 30% softwood kraft pulp (NBKP) and 70% hardwood kraft pulp (LBKP).

The embossing was performed in the "Mt. Fuji embossing" described above, and the embossing pattern had a depth of 1.45 mm.
Calendering was carried out on the paper machine and on the ply machine.

The evaluation involved 20 subjects actually using the toilet rolls of each example for one week, and then making absolute evaluations on a 7-point scale for each of the categories of "softness,""smoothness,""moisture,""fluffiness," and "tear resistance."
The evaluation was based on the following criteria: 7 points: very good, 6 points: good, 5 points: slightly good, 4 points: neutral, 3 points: slightly bad, 2 points: bad, 1 point: very bad.

The measurement methods for the measurements in the table are as follows:

[Basis weight]
Measurement was performed in accordance with JIS P 8124 (1998).

[Paper thickness]
Under the conditions of JIS P 8111 (1998), the thickness was measured according to the above-mentioned thickness measurement method using a dial thickness gauge (thickness measuring instrument) "PEACOCK G type" (manufactured by Ozaki Seisakusho).

[Roll winding density] = theoretical cross-sectional area / roll cross-sectional area Roll cross-sectional area = cross-sectional area of entire roll - cross-sectional area of paper tube Theoretical cross-sectional area = paper thickness x winding length

[Tensile strength and elongation at break]
Tensile speed (vertical) 100 mm/min, (horizontal) 50 mm/min, sample width 25 mm,
Distance between gripping jigs: 100 mm
Measure the strength and elongation at break for two plies. Measuring equipment: Minebea Co., Ltd. "Tension and compression testing equipment TG-200N"

[Tensile modulus (vertical)]
The measurement was carried out five times for one ply at a tensile speed of 10 mm/min, a sample width of 25 mm, and a gripping jig distance of 50 mm, and the average value was taken as the tensile modulus.
Measurement tester: Shimadzu Corporation "EZS-20NX"
Software: "TRAPEZIUMX"

[Work of Breaking (Vertical)]
The integrated value of the load-displacement curve obtained with a tensile speed of 10 mm/min, a sample width of 25 mm, and a gripping jig distance of 50 mm for one ply.
Measurement tester: Shimadzu Corporation "EZS-20NX"
Software: "TRAPEZIUMX"

Table 2 contains an example called a "Reference Example." This is so named because, even though it is within the scope of the present invention, it is not a sufficiently high evaluation.

Based on these comparative examples and examples, it can be said that by adopting the configuration of the present invention, it is possible to produce a toilet roll that is soft enough and resistant to breaking even when rolled into a long length.

1...toilet roll, 10...toilet paper, 20...paper tube (core), L1...toilet roll roll diameter, L2...toilet roll core diameter, L3...toilet roll width.

Claims (3)

Two plies of sanitary tissue paper are stacked and rolled up,
The basis weight per ply is 10.0 to 15.0 g/m ² , the paper thickness per ply is 60 to 95 μm, the outer diameter of the paper core is 20 to 45 mm, and the winding length for two plies is 60 to 90 m;
Furthermore, the tensile modulus per ply is 6.0 to 16.0 N/mm ² and the work at break is 3.0 to 6.0 N·mm;
An embossment is formed on each of the plies, and these are laminated to form a double embossment.
The embossing pattern is a pattern in which embossing recesses each having a rectangular shape in a plan view are arranged in a lattice shape with centers spaced apart from each other in the width direction and the continuous direction of the ply,
A toilet roll comprising: a valley groove formed in the recess so as to connect a corner of the recess to a corner of an adjacent recess.
The tensile modulus and breaking work are values measured in the longitudinal direction of the fiber, and are values measured on a 25 mm wide sample with a gripping jig distance of 50 mm in a tensile tester at a pulling speed of 10 mm/min. The toilet roll according to claim 1, wherein the basis weight per ply is 11.0 to 14.0 g/m2 ^. The toilet roll according to claim 1, wherein the breaking elongation is 6.0 to 12.0%.

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