JP6863499B1 - Sanitary tissue paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hygienic thin paper having excellent water absorption and excellent moisture wiping property. SOLUTION: The hygienic thin paper having a multi-ply structure in which a plurality of thin papers are superposed, and at least one of the two thin papers forming the outer layer of the multi-ply structure is compared with the thin papers adjacent thereto. Sanitary tissue paper with short water absorption time and large water diffusion area. [Selection diagram] Fig. 1

Description

The present invention relates to sanitary thin paper, and more particularly to sanitary thin paper having a multi-ply structure in which two or more sheets of thin paper are superposed.

In the technical field of sanitary tissue paper such as toilet paper and tissue paper, various techniques for effectively wiping off moisture have been proposed.

For example, the toilet paper disclosed in Patent Document 1 absorbs water by stacking three or more sheets to form a set, utilizing the water absorption capacity of each sheet and the gap generated between the sheets. It is capable of having excellent water absorption.

Further, the water-decomposable sanitary paper disclosed in Patent Document 2 has three or more layers, and the water absorption time of the outer layer is shorter than the water absorption time of the inner layer, so that the water absorbed in the outer layer is quickly trapped inside. After that, water is diffused in the inner layer, which has a longer water absorption time than the outer layer, so that not only the water absorption is excellent, but also the strike-through of the water can be prevented.

JP-A-2002-172072 Japanese Patent Application Laid-Open No. 2006-334326

However, in the conventional multi-layer structure, when the moisture is wiped off, the wiped portion of the outer layer is filled with the moisture until the moisture wiped by the outer layer is diffused in the inner layer, and more moisture cannot be absorbed. , The wiped part of the outer layer is easily torn due to the influence of moisture that cannot be absorbed. Therefore, a sanitary tissue paper having excellent water absorption and excellent moisture wiping property is desired.

An object of the present invention is to provide a sanitary tissue paper having excellent water absorption and excellent moisture wiping property.

As a result of diligent studies to solve the above problems, the present inventor forms an outer layer of a multi-ply structure among a plurality of thin papers in a sanitary thin paper having a multi-ply structure in which a plurality of thin papers are superposed. By setting at least one of the two tissue papers to have a shorter water absorption time and a larger water diffusion area than the adjacent tissue papers, a sanitary tissue paper having excellent water absorption and excellent moisture wiping property can be obtained. I found it.

Specifically, the present invention has the following configuration.
[1] A sanitary thin paper having a multi-ply structure in which a plurality of thin papers are superposed, and at least one of the two thin papers forming the outer layer of the multi-ply structure among the plurality of thin papers has a water absorption time of 5 to 18 seconds. And the water diffusion area is 1700 mm ² or more,
Adjacent to the tissue paper , the water absorption time is longer than the water absorption time of the at least one tissue paper, which is 8 to 25 seconds, and the water diffusion area is smaller than the water diffusion area of the at least one tissue paper. Sanitary tissue paper that is 1500 mm ^{2 or more.}
[2] A sanitary thin paper having a multi-ply structure in which three or more thin papers are superposed.
Of the plurality of tissue papers, each of the two tissue papers forming the outer layer of the multi-ply structure has a water absorption time of 5 to 18 seconds and a water diffusion area of 1700 mm ² or more.
The tissue adjacent to it has a water absorption time of 8 to 25 seconds, which is longer than the water absorption time of each tissue paper, and an area in which the water diffusion area is smaller than the water diffusion area of each tissue paper. Sanitary tissue paper with a size of 1500 mm ^{2 or more.}
[3] Of the plurality of thin papers, at least one of the two thin papers forming the outer layer of the multilayer structure is adjacent to the two thin papers so as to have a shorter water absorption time and a larger water diffusion area than the adjacent thin papers. The sanitary tissue paper according to [1] or [2], which has a high crepe density as compared with tissue paper.

When the sanitary tissue paper according to the present invention is used so that the side of the outer layer thin paper having a shorter water absorption time and a larger water diffusion area as a moisture wiping surface as compared with the adjacent thin paper, the outer layer thin paper is wiped off. The obtained water can be absorbed relatively quickly in the thickness direction while being diffused relatively quickly in the surface direction of the thin paper of the outer layer. The thin paper adjacent to the outer layer of thin paper receives the moisture that has passed through the outer layer of thin paper in the thickness direction over a relatively large area, diffuses it at a relatively slow rate in the surface direction, and is relative in the thickness direction. Can be absorbed at a slow rate. In addition, the outer layer of tissue paper and the tissue paper adjacent to the outer layer are superposed so as to be adjacent to each other, and a gap may be formed between the two. Therefore, the sanitary tissue paper uses this gap to remove moisture. Can be retained.

According to the configuration of the present invention, since it is possible to quickly take in water inside and diffuse it internally, the water is saturated in the wiping portion of the thin paper in the outer layer, and the wiping portion is affected by the moisture that cannot be completely absorbed. It is possible to prevent the phenomenon that the tear is likely to occur. In addition, since the moving speed of the moisture taken into the inside is suppressed, the phenomenon of so-called "moisture strike-through" in which the moisture passes through the sanitary tissue paper in the thickness direction and exudes from the surface opposite to the wiping surface is suppressed. can do. Therefore, according to the present invention, it is possible to provide a sanitary tissue paper having excellent water absorption and excellent moisture wiping property.

It is a schematic diagram for demonstrating the structure of the sanitary tissue paper which concerns on embodiment of this invention. It is a schematic diagram which shows the example of the paper machine applicable to the production of thin paper. It is a schematic diagram which shows the example of the ply machine applicable to the manufacture of the secondary raw fabric roll for sanitary tissue paper. It is a schematic diagram which shows the example of the sanitary tissue paper manufactured by the ply machine of FIG. It is a micrograph of the surface of thin paper applicable to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments and drawings have been described for illustrative purposes only and are not intended to limit the present invention.

(First Embodiment)
(Structure of hygienic tissue paper)
FIG. 1 is a schematic view for explaining the structure of sanitary tissue paper according to the embodiment of the present invention. In the figure, the same reference numerals indicate the same components.

FIG. 1A shows a sanitary thin paper according to the present embodiment having a two-ply configuration in which two thin papers (thin papers 101 and 201) are superposed. The thin paper 101 and the thin paper 201 each form an outer layer having a two-ply structure. FIG. 1B shows a sanitary thin paper according to the present embodiment having a three-ply configuration in which three thin papers (thin paper 101, 201, 301) are superposed. The thin paper 101 and the thin paper 301 each form an outer layer having a 3-ply structure. FIG. 1C shows a sanitary thin paper according to the present embodiment having a 4-ply configuration in which four thin papers (thin paper 101, 201, 401, 501) are superposed. The thin paper 101 and the thin paper 501 each form an outer layer having a 4-ply structure.

In each of the multilayer configurations illustrated in FIGS. 1 (a) to 1 (c), the thin paper 101 and the thin paper 201 are superposed so as to be adjacent to each other, and the thin paper 101 forming one outer layer is adjacent to the thin paper 101. Compared to the thin paper 201, the water absorption time is short and the water diffusion area is large.

As described above, the sanitary thin paper according to the present embodiment is a sanitary thin paper having a multi-ply structure in which a plurality of thin papers are superposed. Further, of the plurality of thin papers having a multi-ply structure, at least one of the two thin papers forming the outer layer has a property that the water absorption time is short and the water diffusion area is large as compared with the thin papers adjacent thereto. As long as such requirements are satisfied, the number of the plurality of thin papers constituting the sanitary thin paper according to the present embodiment is not limited to the illustrated example, and may be 2, 3, 4, 5, or more. Well, that is, the multi-ply may be 2-ply, 3-ply, 4-ply, 5-ply, or more plies.

<Water absorption time>
The water absorption time of the thin paper according to the present invention is based on the method for measuring the water absorption of the Japanese Industrial Standard JIS S3104 (1992) "Tissue Paper" (old). One drop of distilled water (23 ± 1 ° C., 0.1 ml) is dropped onto the test piece from a height of 10 mm with a pipette, and the water is completely absorbed from the moment the water drop comes into contact with the test piece, and the reflection on the surface of the test piece. Measure the time until disappears with a stopwatch (in units of 0.1 seconds). This test is performed a total of 5 times, and the average value is taken as the water absorption time.

The water absorption time of each thin paper is preferably about 5 to 25 seconds. The water absorption time of the thin paper forming the outer layer is preferably 5 to 18 seconds, more preferably 7 to 15 seconds. The water absorption time of the thin paper adjacent to the thin paper forming the outer layer is longer than the water absorption time of the thin paper forming the outer layer, preferably about 8 to 25 seconds, and more preferably about 10 to 20 seconds. preferable.

<Water diffusion area>
The water diffusion area of the thin paper according to the present invention is based on the method for measuring the water absorption of Japanese Industrial Standard JIS S3104 (1992) "Tish Paper" (old). One drop of distilled water (23 ± 1 ° C., 0.1 ml) was dropped onto the test piece from a height of 10 mm with a pipette, and the spread was 30 seconds after the moment when the water drop came into contact with the test piece. The maximum length (mm) of the spread in each of the direction and the CD direction is measured to obtain the product of the two. This test is performed a total of 5 times, and the average value is taken as the water diffusion area.

The water diffusion area of each thin paper ^{is preferably 1500 mm 2} or more. The water diffusion area of the thin paper forming the outer layer ^{is preferably 1700 mm 2} or more, and more preferably 1900 mm ² or more. The water diffusion area of the thin paper that forms the outer layer is smaller than the water diffusion area of the thin paper that forms the outer layer, ^{and is preferably 1500 mm 2} or more, and more preferably 1600 mm ² or more.

(Action effect)
The effects of the first embodiment of the present invention will be described with reference to FIG. 1 (a).

The thin paper 101 has the properties that the water absorption time is short and the water diffusion area is large as compared with the adjacent thin paper 201. When the sanitary thin paper is used so that the surface composed of the thin paper 101 on both the front and back surfaces serves as a wiping surface for wiping off the moisture, the wiped moisture is wiped off by the thin paper 201 without passing through the thin paper 101. At the same time, it is rapidly diffused in the surface direction of the thin paper, and at the same time, it is rapidly absorbed in the thickness direction of the thin paper. Moisture absorbed in the thickness direction while being diffused in the surface direction in the thin paper 101 in this way is absorbed by the thin paper 201 after passing through the thin paper 101 in the thickness direction.

At this time, since the water is diffused to some extent in the surface direction via the thin paper 101, the thin paper 201 can receive the water that has passed through the thin paper 101 in a relatively large area. The thin paper 201 has a property of having a longer water absorption time than the adjacent thin paper 101, but since it can receive water in such a relatively large area, the thin paper 201 is based on the difference in water absorption time between the thin papers. Moisture that 201 cannot absorb immediately is unlikely to occur.

Further, the thin paper 101 and the thin paper 201 are overlapped so as to be adjacent to each other, so that a gap may be formed between the thin paper 101 and the thin paper 201. Therefore, even if water that cannot be completely absorbed by the thin paper 201 is generated based on the difference in water absorption time between the thin papers, the sanitary thin paper utilizes the gap generated between the thin paper 101 and the thin paper 201. , Can retain moisture.

As described above, the sanitary tissue paper according to the embodiment of the present invention can absorb water by utilizing the water absorption capacity of the gaps generated between the tissue papers in addition to the water absorption capacity of each tissue paper constituting the sanitary tissue paper. As a whole thin paper, moisture can be quickly taken into the composition and can exhibit excellent water absorption. Further, due to this excellent water absorption, it is possible to prevent the phenomenon that the moisture is saturated in the wiped portion of the thin paper 101 of the outer layer and the wiped portion is easily torn due to the influence of the moisture that cannot be completely absorbed.

Further, since the thin paper 201 has a longer water absorption time and a smaller water diffusion area than the adjacent thin paper 101, the moisture passing through the thin paper 101 relatively quickly is then relatively slow in the thin paper 201. Therefore, it diffuses in the surface direction and is absorbed in the thickness direction at the same time. That is, the moisture wiped off by the sanitary tissue paper moves rapidly in the tissue paper 101 and then slowly in the tissue paper 201. Therefore, the sanitary tissue paper not only quickly takes in the moisture inside but also takes it inside. However, the water can be retained inside for a relatively long time. As a result, the so-called "moisture strike-through" phenomenon in which the wiped water seeps out from the surface opposite to the wiped surface of the sanitary tissue paper can be suppressed.

Therefore, according to the embodiment of the present invention, it is possible to provide a sanitary tissue paper having excellent water absorption and excellent moisture wiping property.

As described above, the action and effect according to the first embodiment of the present invention have been described with reference to the sanitary tissue paper having a two-ply structure shown in FIG. 1 (a). The 3-ply sanitary tissue paper shown in FIG. 1 (b) and the 4-ply sanitary tissue paper shown in FIG. 1 (c) are similar to the 2-ply sanitary tissue paper shown in FIG. 1 (a). It includes 101 and 201, and similar description may be applied to its action and effect. Even for sanitary paper with a multi-ply configuration of 5 plies or more (not shown), at least one of the two thin papers forming the outer layer of the multi-ply configuration has a shorter water absorption time and a smaller water diffusion area than the adjacent thin paper. As long as it has great properties, it can exert the above-mentioned effects.

(Tissue paper)
Tissue paper, which is a component of sanitary tissue paper, is obtained by making a slurry containing a pulp component which is a fiber raw material. Since thin paper corresponds to a base paper for producing sanitary thin paper, the thin paper is also hereinafter referred to as "base paper" or "base paper sheet".

(Pulp component)
Examples of the pulp component include wood pulp, non-wood pulp, and deinked pulp. Examples of wood pulp include broadleaf pulp (blightwood kraft pulp (LKP)), coniferous tree pulp (coniferous kraft pulp (NKP)), sulfite pulp (SP), dissolved pulp (DP), soda pulp (AP), and unbleached craft. Examples thereof include chemical pulp such as pulp (UKP) and oxygen bleached kraft pulp (OKP). Further, semi-chemical pulp such as semi-chemical pulp (SCP) and chemiground wood pulp (CGP), mechanical pulp such as crushed wood pulp (GP) and thermomechanical pulp (TMP, BCTMP) can be mentioned, but are not particularly limited. Examples of the non-wood pulp include cotton pulp such as cotton linter and cotton lint, non-wood pulp such as hemp, straw and bagasse, and cellulose, chitin and chitosan isolated from squirrel and seaweed, but are not particularly limited. .. Examples of the deinked pulp include deinked pulp made from used paper, but the deinking pulp is not particularly limited. As the pulp component, one of the above may be used alone, or two or more of them may be mixed and used. Since these pulp components greatly affect the quality of sanitary tissue paper, they are appropriately blended in a predetermined type and blending ratio according to the required quality.

For example, as the pulp component, at least one selected from softwood pulp and hardwood pulp can be preferably used. Softwood pulp has long fibers and strength, and can impart strength to the thin paper to be made. In addition, hardwood pulp has short fibers, and the thin paper produced can provide uniformity and texture. In the embodiment of the present invention, it is preferable to use softwood pulp and hardwood pulp in combination, and it is more preferable to use softwood kraft pulp (NKP) and hardwood kraft pulp (LKP) in combination.

When softwood pulp and hardwood pulp are used in combination as a pulp component, the L / N ratio indicating the mixing ratio (mass ratio) of softwood pulp and hardwood pulp is preferably, for example, 10/90 to 90/10. It is more preferably 20/80 or more, further preferably 30/70 or more, further preferably 80/20 or less, and further preferably 70/30 or less.

(Arbitrary ingredient)
Various chemicals may be added to the base paper sheet as optional components for the required quality and stable operation. Examples of the optional component include a dry paper strength agent, a wet paper strength agent, a softener, a bulking agent, a dye, a fragrance, a dispersant, a drainage improver, a pitch control agent, a yield improver, a sizing agent, and the like. Can be done. Examples of the dry paper strength agent include cationized starch, polyacrylamide (PAM), carboxymethyl cellulose (CMC) and the like. Examples of the wet paper strength agent include polyamide epichlorohydrin, urea, melamine, and heat-crosslinkable polyacrylamide. Examples of the softener include anionic surfactants, nonionic surfactants, cationic surfactants, and zwitterionic surfactants. The above optional components may be used alone or in combination of two or more.

(Basis weight)
The basis weight of the base paper sheet can be ^{, for example, 7 to 30 g / m 2} according to the required quality of the thin paper and the sanitary thin paper. For example, the basis weight of the base paper sheet ^{can be preferably 9 g / m 2} or more, and preferably 25 g / m ² or less. Basis weight is measured according to the provisions of Japanese Industrial Standard JIS P8124.

(Production method)
The sanitary tissue paper according to the embodiment of the present invention is
-A process of manufacturing a primary raw fabric roll in which a base paper sheet is wound while making a thin paper (base paper sheet), which is a component of the process.
-The base paper sheet is unwound from each of the plurality of primary raw fabric rolls on which the base paper sheet is wound, and the plurality of base paper sheets are overlapped with each other to form a laminated sheet having a multi-ply structure, and the laminated sheet is wound around a winding core. The process of manufacturing secondary raw paper rolls for sanitary tissue paper,
・ Laminated sheets are unwound from the secondary raw paper roll for sanitary tissue paper, and if necessary, through processes such as slitting, embossing, perforation, folding, winding, and cutting, a bundle of paper of a predetermined amount and size is used. It can be manufactured through steps such as processing into sanitary tissue paper (products) in the form of forms or rolls.

Hereinafter, the main manufacturing process of sanitary tissue paper will be described with reference to the drawings.

(Manufacturing of tissue paper)
With reference to FIG. 2, a step of manufacturing a primary raw fabric roll in which a base paper sheet is wound while making a thin paper (base paper sheet) applicable to the embodiment of the present invention will be described.

[Paper machine]
FIG. 2 schematically shows an example of a paper machine for producing a primary raw fabric roll in which a base paper sheet is wound while making a thin paper (base paper sheet) applicable to the embodiment of the present invention.

The paper machine 1 includes a wire part 40, a press part 42, a dry part 44, a calendar part 45, and a reel part 46.

The wire part 40 includes wires 2 and 3 in which a papermaking net is formed as an endless belt, and a head box 8 for spraying pulp slurry. In this embodiment, a twin wire former type paper machine is used, but known paper machines such as a circular net former type, a suction prestoformer type, and a crescent former type may be used.

The pulp slurry supplied to the paper machine is made into a slurry by adding water and, if necessary, an optional component such as a paper strength agent to the pulp component and beating it.

In the wire part 40, the pulp slurry 9 is thinly sprayed from the head box 8 toward the nip portions of the wires 2 and 3.

Next, the wire 2 and the wire 3 are crimped by the forming roll 12, and the sprayed pipe slurry is squeezed out of water from the mesh of the wires 2 and 3 to become the wet paper 10. The process in the wire part 40 is also collectively referred to as a "wet paper manufacturing process".

Next, the wet paper 10 on the wire 3 is sent to the press part 42 by the rotation of the wire 3. The press part 42 includes a dryer felt 22 having the felt formed of an endless belt, and a plurality of felt rolls arranged so as to abut against the dryer felt 22 and rotating with the running of the dryer felt 22.

The wet paper 10 sent from the wire part 40 is placed on the surface of the dryer felt 22, and the moisture of the wet paper 10 is absorbed by the fibers of the dryer felt 22, so that the wet paper 10 is dehydrated. The process in the press part 42 is also collectively referred to as a "dehydration process".

Next, the wet paper 10 dehydrated by the press part 42 is sent to the dry part 44. The dry part 44 includes a heatable columnar Yankee dryer 26, which dries the wet paper 10 to remove moisture. That is, steam is blown into the inside, and the wet paper 10 is pressure-bonded to the outer peripheral surface of the heated Yankee dryer 26 to be dried, and the wet paper sheet is made into a dry state sheet. A hood 28 having a hot air injection port facing the outer peripheral surface of the Yankee dryer 26 may be further provided, and the hot air from the hood 28 may also be added to the wet paper 10 to be dried. The sheet dried on the outer peripheral surface of the Yankee dryer 26 is peeled off from the surface of the Yankee dryer 26 while being formed with very fine wrinkles called crepes by the crepe doctor 29. The process in the dry part 44 is also collectively referred to as a "drying process". In particular, the series of steps involved in applying crepe to the sheet is also referred to as "creping". Crepe is performed to give the sheet softness, bulkiness (bulk feeling), absorbency, aesthetic appearance (crepe shape), and feel.

The peeled sheet 31 is sent to the calendar part 45. The calendar part includes a pair of calendar rolls 53 and 54, and the sheet 31 is sandwiched and pressed from above and below by the pair of calendar rolls. As a result, the sheet 31 is compressed, and the paper thickness is adjusted and made uniform, and the surface is smoothed. This process is also collectively referred to as "calendar processing".

The sheet 31 sent from the calendar part 45 is then sent to the reel part 46. In the reel part 46, the sheet 31 is fixed to the winding core 38 of the reel 34, the reel 34 is rotated, and the sheet 31 is wound up. As a result, a paper roll 36 in which the sheet 31 is wound into a roll is obtained. The process in the reel part 46 is also collectively referred to as a "winding process". The sheet 31 wound in this way becomes a thin paper (base paper sheet) applicable to the embodiment of the present invention.

The paper roll 36 in which the thin paper (base paper sheet) 31 is wound up can be used as a primary roll for producing sanitary thin paper according to the embodiment of the present invention.

(Manufacturing of secondary raw fabric rolls for sanitary tissue paper)
Next, with reference to FIG. 3, a step of manufacturing a secondary raw fabric roll for sanitary thin paper according to the embodiment of the present invention from the primary raw fabric roll will be described. In this example, a 3-ply secondary raw fabric roll in which three base paper sheets are laminated is manufactured. However, the present embodiment is not limited to this, and is applicable to the production of a multi-ply secondary raw fabric roll in which two or more base paper sheets are laminated.

[Ply machine]
FIG. 3 is a schematic view showing an example of a ply machine applicable to the production of a secondary raw fabric roll for sanitary tissue paper according to an embodiment of the present invention.

The base paper sheets 31a, 31b, 31c unwound from each of the three primary rolls 36a, 36b, 36c are laminated on the paper roll 51 so as to form a multi-ply configuration. The laminated body of the base paper sheets (hereinafter, also referred to as “laminated sheet”) 52 is guided by the reel drum 56 and rolled onto the winding core while being cut to a predetermined width by the slitter part 55 as needed. .. As a result, as shown in the side view of FIG. 4A, a secondary raw fabric roll 58 for sanitary tissue paper in which the laminated sheet 52 is wound in a roll shape is obtained. FIG. 4B is a partially enlarged view of the laminated sheet 52 showing the portion of IVb of FIG. 4A. As shown in FIG. 4B, the laminated sheet 52 is a stack of a plurality of base paper sheets 31. In this example, three base paper sheets 31 are overlapped, but this number is an example and is not intended to limit the present invention.

The secondary raw fabric roll 58 for sanitary tissue paper thus obtained is then subjected to product processing. Specifically, a laminated sheet is unwound from a secondary raw fabric roll for sanitary tissue paper, and if necessary, undergoes processes such as slitting, embossing, perforation, folding, winding, and cutting, and a predetermined amount and It is processed into sanitary tissue paper in the form of bundles of paper size or sanitary tissue paper in the form of rolls.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIG. 1 (b). Unless otherwise stated, the configurations applicable to the first embodiment are applicable to the present embodiment. This embodiment is applicable to sanitary tissue paper having a multi-ply structure in which a plurality of tissue papers of 3 or more are superposed. The number of the plurality of thin papers constituting the sanitary thin paper according to the present embodiment is not limited to the illustrated example, and may be 3, 4, 5, or more, that is, the multiply is 3. It may be a ply, a 4-ply, a 5-ply, or a higher ply.

As described above, the sanitary thin paper shown in FIG. 1B has a three-ply configuration in which three thin papers (thin paper 101, 201, 301) are superposed. The thin paper 101 and the thin paper 301 each form an outer layer having a 3-ply structure. The thin paper 101 and the thin paper 201 are superposed so as to be adjacent to each other, and the thin paper 101 forming one outer layer has a property that the water absorption time is short and the water diffusion area is large as compared with the thin paper 201 adjacent thereto. ..

In addition, in the second embodiment, the tissue paper 301 and the tissue paper 201 are superposed so as to be adjacent to each other, and the tissue paper 301 forming the other outer layer is compared with the tissue paper 201 adjacent thereto. It has the property that the water absorption time is short and the water diffusion area is large.

That is, in the sanitary thin paper according to the second embodiment, each of the two thin papers (thin papers 101 and 301) forming the outer layer of the multi-ply structure in which a plurality of thin papers are superposed is combined with the adjacent thin papers (thin paper 201). In comparison, the water absorption time is short and the water diffusion area is large. As long as this requirement is satisfied, the two thin papers (thin papers 101 and 301) can be used regardless of the length of the water absorption time and the size of the water diffusion area between the two thin papers (thin papers 101 and 301) forming both outer layers. It may be the same or different.

(Action effect)
The effects of using sanitary tissue paper so that the side of the outer layer of tissue paper, which has a shorter water absorption time and a larger water diffusion area than the adjacent tissue paper, serves as a moisture wiping surface will be described in the first embodiment. As you did. That is, according to the embodiment of the present invention, it is possible to provide a sanitary tissue paper having excellent water absorption and excellent moisture wiping property. In addition, in the second embodiment, since the outer layer of tissue paper having a shorter water absorption time and a larger water diffusion area than the adjacent tissue paper is provided on both sides of the sanitary tissue paper, it is not necessary to specify the moisture wiping surface. It can exert a further effect of improving the degree of freedom of use when wiping off water.

As described above, the action and effect according to the second embodiment of the present invention have been described with reference to the sanitary tissue paper having a 3-ply structure shown in FIG. 1 (b).

This embodiment can also be applied to the sanitary tissue paper having a 4-ply structure shown in FIG. 1 (c). In the sanitary thin paper shown in FIG. 1 (c), each of the two thin papers (thin paper 101, 501) forming the outer layer of the multi-ply structure (4-ply structure) in which a plurality of (4) thin papers are overlapped is used. Compared with the thin paper (thin paper 201, 401) adjacent thereto, the water absorption time may be short and the water diffusion area may be large. As long as this requirement is satisfied, the relationship between the length of the water absorption time and the size of the water diffusion area between the two thin papers (thin papers 101 and 501) forming both outer layers does not matter. Further, the relationship between the length of the water absorption time and the size of the water diffusion area between the two thin papers (thin papers 201 and 401) adjacent to each of the two thin papers (thin papers 101 and 501) forming both outer layers does not matter. The two outer layers of thin paper (thin paper 101, 501) may be the same or different. Further, the two thin papers (thin paper 201, 401) adjacent to each of the two outer layers of thin paper (thin paper 101, 501) may be the same or different.

By making the combination of the thin paper forming the outer layer and the thin paper adjacent thereto having the same configuration on both the front and back sides of the sanitary thin paper, it is not necessary to specify the surface to be wiped with moisture, and the degree of freedom of use when wiping moisture is improved. The effect of the above-described embodiment is further enhanced. In addition, on both the front and back sides of the sanitary thin paper, the combination of the thin paper forming the outer layer and the thin paper adjacent thereto has a different configuration, thereby imparting different functions to both the front and back sides while ensuring excellent water absorption and moisture wiping property. be able to.

Similarly, the present embodiment can be applied to sanitary paper having a multi-ply configuration of 5 plies or more (not shown). As long as each of the two thin papers forming the outer layer of the multi-ply structure has a property that the water absorption time is short and the water diffusion area is large as compared with the thin papers adjacent thereto, the invention according to the present embodiment described above. It can exert an action effect. At this time, the length of the water absorption time and the size of the water diffusion area of the thin paper included in the multi-ply configuration and different from the thin paper forming the outer layer and the adjacent thin paper are not limited.

(Other embodiments)
Unless otherwise stated, the configurations applicable to the first and second embodiments are applicable to the present embodiment. This embodiment is applicable to sanitary tissue paper having a multi-ply structure in which two or more tissue papers are superposed.

(Means for Achieving the Invention)
In order to realize the sanitary thin paper according to the above-described embodiment of the present invention, at least two types of thin paper having different water absorption times and water diffusion areas are required. Specifically, at least two types of tissue paper are required: one tissue paper having a relatively short water absorption time and a large water diffusion area, and another tissue paper having a relatively long water absorption time and a small water diffusion area.

(Achievement method)
Examples of methods for obtaining two types of tissue paper having such a relationship include a method for obtaining two types of tissue paper by different raw materials, a method for obtaining two types of tissue paper by different conditions other than the raw materials, and a method for obtaining these two types of tissue paper. A method consisting of any combination can be mentioned.

(Achievement method in terms of raw materials)
As a method of obtaining two types of thin paper by using different raw materials, for example, a method of adjusting the mixing ratio (L / N ratio) of softwood pulp and hardwood pulp in the pulp component, a chemical agent (for example, a softener, a sizing agent, etc.) ), A method of adjusting the amount of the addition thereof, and any combination thereof.

(Adjustment of L / N ratio)
In the case of the method of adjusting the L / N ratio, when other conditions are the same, the higher the blending ratio of hardwood pulp (L), the smaller the water diffusion area of the thin paper tends to be, and the blending of softwood pulp (N). The higher the ratio, the larger the water diffusion area of the thin paper tends to be. Therefore, in one tissue paper used for the outer layer, the water diffusion area can be adjusted by increasing the blending ratio of the softwood pulp as compared with other tissue papers adjacent thereto.

(Adjustment of drug type and addition amount)
In the case of a method for adjusting the type of a drug (for example, a softener, a sizing agent, etc.) and the amount of the drug added, the measures that can be taken differ depending on the characteristics of the drug. When the softener imparts flexibility by introducing a lipophilic group into the pulp component, the water absorption time of the thin paper tends to be longer as the amount of the softener added is larger. In that case, the water absorption time of the outer layer of thin paper can be adjusted by reducing the amount of the softener added as compared with the thin paper adjacent to it. Further, the sizing agent is generally added for the purpose of imparting water repellency, and the larger the amount of the sizing agent added, the longer the water absorption time of the thin paper tends to be. In that case, the water absorption time of the outer layer of thin paper can be adjusted by reducing the amount of the sizing agent added as compared with the thin paper adjacent to it. Further, the water absorption time of the two types of thin paper may be adjusted simply by using chemicals having different characteristics.

(Achievement method other than raw materials)
Further, as a method of obtaining two types of thin paper by different conditions other than raw materials, for example, adjustment of crepe ratio, adjustment of jet wire ratio (J / W ratio), adjustment of density, adjustment of paper thickness, suitable for processing. Adjustment etc. can be mentioned.

(Adjustment of crepe rate)
A method of obtaining two types of thin paper by adjusting the crepe ratio of the thin paper will be described with reference to FIGS. 2 and 5.

(Crepe rate)
The crepe ratio of thin paper in the present embodiment is defined based on the peripheral speed difference between the Yankee dryer and the take-up reel in the paper machine (peripheral speed of the take-up reel ≤ peripheral speed of the Yankee dryer), and is defined by the following equation. Calculated according to (I).
Crepe rate (%) = 100 x (Yankee dryer peripheral speed (m / min) -winding reel peripheral speed (m / min)) / winding reel peripheral speed (m / min) ... (I)

With reference to FIG. 2, specifically, in the paper machine 1, the base paper sheet obtained by varying one or both of the peripheral speed of the Yankee dryer 26 and the peripheral speed of the take-up reel 34 ( The crepe rate of (thin paper) 31 can be adjusted.

The crepe rate of each thin paper can be, for example, 10 to 40% from the viewpoint of required quality and operability. For example, the crepe rate of each tissue paper is preferably 28% or less, more preferably 26% or less. Further, for example, the crepe rate of each thin paper sheet is preferably 15% or more. By setting the crepe ratio within the above range, it is possible to impart an appropriate uneven structure to the surface to obtain good touch and water absorption, and prevent deterioration of durability during use.

5 (a) and 5 (b) show micrographs of thin paper with different crepe densities obtained by different crepe rates during the production of thin paper.

<Crepe density>
The crepe density of the thin paper according to the present invention refers to the number of crepe ridges on the surface of the thin paper on a line segment having a unit length of 1 cm in the MD direction. The crepe density can be measured as follows. First, a magnified image of the sheet surface is taken using an optical microscope. The magnification may be as long as the number of crepe piles can be confirmed, and can be, for example, about 40 times. At the time of photographing, in order to make it easy to confirm the crepe pile from the photographed image, the imaged surface may be irradiated with light to shade the surface of the thin paper with light. Next, the number of crepe ridges on a line segment having a unit length of 1 cm (actual size) in the MD direction is visually counted from the captured image. If the size of the captured image is less than 1 cm in the MD direction, the number of crepe ridges on the line segment of the predetermined length (actual size) in the MD direction is visually counted, and the MD direction is based on the numerical value. The number of crepes per 1 cm of unit length may be calculated. For example, the number of crepe ridges on a line segment of 0.5 cm (actual size) in the MD direction is visually counted, and the number of crepes measured is doubled to calculate the number of crepes per 1 cm of unit length in the MD direction. You may try to do it. The measured value shall be the average value of any three places (three lines) of the captured image.

The tissue paper shown in FIG. 5 (a) has a crepe density of 48 sheets / cm, and the tissue paper shown in FIG. 5 (b) has a crepe density of 40 sheets / cm. The crepe density in this case is obtained by visually counting the number of crepe peaks on the line segment of 0.5 cm (actual size) in the MD direction from the photographed image shown in FIG. 5, and doubling the measured number. The number of crepes per 1 cm of unit length in the MD direction is used.

According to the present inventor, when the other conditions are the same, the higher the crepe density, the larger the water diffusion area of the thin paper and the shorter the water absorption time, and the lower the crepe density, the larger the water diffusion area of the thin paper. Was found to tend to be smaller and the water absorption time to be longer. Further, the crepe density tends to increase as the crepe rate increases, and the crepe density tends to decrease as the crepe rate decreases. The crepe density of tissue paper can be controlled by adjusting the crepe rate during the production of tissue paper.

In one embodiment of the present invention, tissue paper having a relatively high crepe density as shown in FIG. 5 (a) is used as the tissue paper forming the outer layer of the multiply configuration, as shown in FIG. 5 (b). Tissue paper with a relatively low crepe density is used for the tissue paper adjacent to the tissue paper forming the outer layer of the multi-ply structure. As a result, it is possible to obtain a sanitary thin paper in which at least one of the two thin papers forming the outer layer of the multi-ply structure has a short water absorption time and a large water diffusion area as compared with the adjacent thin paper.

According to the present embodiment, a plurality of thin papers having a desired relationship with respect to water absorption time and water diffusion area can be easily obtained by simply adjusting only the crepe ratio without changing other conditions. In addition, the crepe density of tissue paper can be used as an index of the applicability of the tissue paper to the production of sanitary tissue paper.

The crepe density of the thin paper forming the outer layer is preferably 30 to 60 sheets / cm, and more preferably 35 to 55 sheets / cm. The crepe density of the thin paper adjacent to the thin paper forming the outer layer is lower than the crepe density of the thin paper forming the outer layer, preferably 20 to 50 sheets / cm, and 25 to 45 sheets / cm. Is more preferable.

In one example, for example, by adjusting the crepe rate of each tissue paper to 15 to 25%, a plurality of tissue papers having a crepe density in the range of 40 to 50 sheets / cm applicable to the present embodiment can be obtained. Can be done.

(Adjustment of J / W ratio)
With reference to FIG. 2, a method of obtaining two types of thin paper by adjusting the J / W ratio will be described.

(J / W ratio)
The jet wire ratio (J / W ratio) is also referred to as the ejection speed (extracted water flow velocity, slurry supply velocity) when the pulp slurry 9 is ejected from the head box 8 in the wire part 40 with reference to FIG. ) Is the jet speed (J), and the traveling speed of the wire is the wire speed (W).

The J / W ratio is an index for controlling the fiber orientation in thin paper. If the jet speed (J) is slow and the wire speed (W) is fast, the J / W ratio will be less than 1. On the contrary, if the jet speed (J) is high and the wire speed (W) is slow, the J / W ratio becomes larger than 1. In any of these cases, fiber orientation is likely to occur in the MD direction in the formed tissue paper. When the J / W ratio is around 1, the fiber orientation in tissue paper is relatively isotropic.

Therefore, when water droplets are dropped on the produced tissue paper, the smaller the J / W is when the J / W ratio is less than 1, and the larger the J / W is when the J / W ratio is larger than 1, the more the water content is. It is easy to diffuse in the MD direction in which the fibers are oriented. On the other hand, when the J / W ratio is around 1, the moisture is easily absorbed in the thickness direction of the thin paper, and is relatively difficult to be diffused in the MD direction.

Therefore, the water diffusion area can be adjusted by assuming that the outer layer of thin paper is manufactured under conditions where the J / W ratio is different from that of the adjacent thin paper. The J / W ratio can be controlled by adjusting one or both of the jet speed and the wire speed.

(Adjustment of density)
A method of obtaining two types of thin paper by adjusting the density of the thin paper will be described.

(density)
The density of thin paper can be obtained from the basis weight and thickness of thin paper, and is calculated by the following formula (II).
Density (g / cm ³ ) = Basis weight (g / m ² ) / Paper thickness (μm) ・ ・ ・ (II)

The density of each tissue paper can be ^{, for example, 0.050 to 0.300 g / cm 3} according to the required quality of the tissue paper and the sanitary tissue paper. For example, the density of tissue paper is preferably, to 0.100 g / cm ³ or more, and preferably may be a 0.200 g / cm ³ or less.

The density of tissue paper can affect water permeability. In the case of the method of adjusting the density, when other conditions are the same, the lower the density, the shorter the water absorption time tends to be, and the higher the density, the longer the water absorption time tends to be. Therefore, in one thin paper used for the outer layer, the water absorption time can be adjusted by lowering the density as compared with other thin papers adjacent thereto.

With reference to FIG. 2, the density of the thin paper is determined, for example, by changing the pressing conditions in the calendar part 45 to adjust the paper thickness, and changing the amount of the pulp slurry 9 sprayed from the head box 8 in the wire part 40. It can be adjusted by the method of adjusting the basis weight or a combination thereof.

(Adjustment of paper thickness)
A method of obtaining two types of thin paper by adjusting the thickness of the thin paper will be described.

(Paper thickness)
The thickness of thin paper is measured according to the Japanese Industrial Standards JIS P8118 (2014).

The thickness of each tissue paper can be, for example, 30 to 250 μm according to the required quality of the tissue paper and the sanitary tissue paper. For example, the thickness of the thin paper can be preferably 50 μm or more, and preferably 200 μm or less.

When the basis weight of the thin paper is the same, the thinner the paper, the higher the density, and the thicker the paper, the lower the density. As described above, the lower the density of the tissue paper, the shorter the water absorption time tends to be, and the higher the density, the longer the water absorption time tends to be. Therefore, when the basis weight of the thin paper is the same, the water absorption time can be shortened and the water absorption time can be adjusted by increasing the thickness of one thin paper used for the outer layer as compared with other thin paper adjacent to it. It will be possible.

(Adjustment of processing orientation)
A method of obtaining two types of thin paper by adjusting the processing orientation of the thin paper will be described with reference to FIGS. 2, 3 and 4.

In the thin paper (base paper sheet) 31 made by the paper machine 1 of FIG. 2, the Yankee surface, which is the surface crimped to the outer peripheral surface of the Yankee dryer 26, becomes the outside of the winding of the primary roll 36, and the Yankee surface. The non-Yankee surface, which is the opposite surface, is wound around the primary original roll 36 so as to be inside the primary original roll 36.

A mold release agent is used on the outer peripheral surface of the Yankee dryer 26 in order to facilitate the peeling of the dried sheet 31. Therefore, the release agent adheres to the Yankee surface of the thin paper, so that the Yankee surface has a smaller water diffusion area than the non-Yankee surface. Therefore, in the ply processing process in which a plurality of thin papers (base paper sheets) are laminated to form a multi-ply structure (laminated sheet), the thin paper that forms the outer layer of the multi-ply structure has a relatively large water diffusion area. By arranging the non-yanky surface so as to be outside the multi-ply configuration, the water diffusion area of the outer layer of tissue paper can be increased. At this time, by arranging the thin paper adjacent to it in such a direction that the Yankee surface having a relatively small water diffusion area comes into contact with the thin paper of the outer layer, moisture is provided between the outer thin paper and the adjacent thin paper. A difference in water diffusion area with respect to the surface on the wiping side can be provided.

In the examples shown in FIGS. 3 and 4, in the process of ply processing in which a plurality of thin paper sheets (base paper sheets) 31 are laminated to form a multi-ply structure (laminated sheet) 52, the outer layer of the multi-ply structure 52 is formed. The thin papers 31a and 31c are arranged so that the Yankee surface, which has a relatively small water diffusion area, is on the outside of the multiply configuration. On the other hand, in the ply machine shown in FIG. 3, the outer layer is formed so that the non-Yankee surface is on the outside by reversing the pull-out direction of the base paper sheets 31a and 31c of the primary rolls 36a and 36c. The orientation of the thin paperboard to be placed can be reversed. Alternatively, in the paper machine shown in FIG. 2, the base paper sheet 31 is wound in the opposite direction, and the base paper sheet 31 is wound so that the Yankee surface is inside the primary original roll 36. In the ply machine shown, the thin paper that forms the outer layer of the multi-ply configuration without reversing the pull-out directions of the base paper sheets 31a and 31c has a non-Yankee surface having a relatively large water diffusion area on the outside of the multi-ply configuration. It can be arranged in such an orientation. In this way, the water diffusion area can be adjusted by adjusting the processing direction. It should be noted that the processing orientation in the above description is exemplary and is not intended to limit the present invention.

As described above, regarding the means for achieving the present invention, various methods for obtaining two types of thin paper having a relationship in which one thin paper has a shorter water absorption time and a larger water diffusion area than other thin papers have been described.

One embodiment of the present invention includes crepe ratio, L / N ratio, density, paper thickness, type of agent (eg, softener, sizing agent) and its addition amount, J / W ratio, and processing orientation (Yankee surface). -Adjusts at least one of the non-Yankee planes). Preferably, in one embodiment of the invention, only the crepe rate is adjusted, with the other conditions being the same. According to this embodiment, very easy adjustment is possible.

One embodiment of the present invention includes crepe ratio, L / N ratio, density, paper thickness, type of agent (eg, softener, sizing agent) and its addition amount, J / W ratio, and processing orientation (Yankee surface). -Adjusts at least two of the non-Yankee planes). Preferably, in one embodiment of the invention, the other conditions are the same and the L / N ratio and density are adjusted. In this embodiment, thin paper having a relatively high blending ratio of softwood pulp and a low density is used as the thin paper forming the outer layer, and thin paper having a relatively high blending ratio of broad-leaved pulp and a high density is used as the thin paper adjacent thereto. Therefore, the relationship between the desired water absorption time and the water diffusion rate can be easily realized. Also, preferably, in one embodiment of the present invention, the processing orientation and density are adjusted under the same conditions. As described above, according to the embodiment of the present invention, the desired relationship between the water absorption time and the water diffusion rate can be easily realized by adjusting a few parameters.

(Use of the invention)
Examples of sanitary tissue paper to which the present invention can be applied include tissue paper, dust paper, paper towels, kitchen paper, and toilet paper.

The sanitary tissue paper according to the embodiment of the present invention can be preferably used for "wiping", that is, "removing / removing" with a "wiping / wiping" operation. Further, not only that, it can also be preferably used for the purpose of simply "contacting" and "removing / removing" without the "wiping / wiping" operation.

1 Paper Machine 2, 3 Wire 8 Head Box 9 Pulp Slurry 10 Wet Paper 12 Forming Roll 22 Dryer Felt 26 Yankee Dryer 28 Hood 31 Sheet / Base Paper 34 Reel 36 Paper Roll 38 Core 40 Wire Part 42 Press Part 44 Dry Part 45 Calendar Part 46 Reel Part 51 Paper roll 52 Laminated sheet 53 Calendar roll 54 Calendar roll 55 Slitter part 56 Reel drum 58 Secondary wire roll 101, 201, 301, 401, 501 Thin paper

Claims (3)

A sanitary tissue paper having a multi-ply structure in which a plurality of tissue papers are superposed.
Of the plurality of thin papers, at least one of the two thin papers forming the outer layer of the multiply configuration has a water absorption time of 5 to 18 seconds and a water diffusion area of 1700 mm ² or more.
The tissue adjacent to it has a water absorption time of 8 to 25 seconds, which is longer than the water absorption time of the at least one tissue paper, and an area where the water diffusion area is smaller than the water diffusion area of the at least one tissue paper. Sanitary tissue paper characterized by being 1500 mm ² or more. The plurality is an integer of 3 or more, and is
Of the plurality of thin papers, each of the two thin papers forming the outer layer of the multiply configuration has a water absorption time of 5 to 18 seconds and a water diffusion area of 1700 mm ² or more.
The tissue adjacent to it has a water absorption time of 8 to 25 seconds, which is longer than the water absorption time of each tissue paper, and an area in which the water diffusion area is smaller than the water diffusion area of each tissue paper. The sanitary tissue paper according to claim 1, wherein the tissue paper has a size of 1500 mm ² or more. Of the plurality of thin papers, at least one of the two thin papers forming the outer layer of the multi-ply configuration is adjacent to the plurality of thin papers so that the water absorption time is shorter and the water diffusion area is larger than that of the adjacent thin papers. The sanitary tissue paper according to claim 1 or 2, which has a higher crepe density as compared with tissue paper.

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